THE CYCLOPAEDIA OF ANATOMY AND PHYSIOLOGY VOL. V. (SUPPLEMENTARY VOLUME.) LONDON : PRINTED BY SPOTTISWOODE AND CO. NEW-STBBET SQXTABE. THE CYCLOPAEDIA OP ANATOMY AND PHYSIOLOGY. EDITED BY ROBERT B. TODD, M.D. F.R.S. FELLOW OF THE EOYAL COLLEGE OF PHYSICIANS; PHYSICIAN TO KING'S COLLEGE HOSPITAL; AND FORMERLY PROFESSOR OF PHYSIOLOGY AND OF GENERAL AND MORBID ANATOMY IN K.ING*S COLLEGE, LONDON, ETC. ETC. VOL. V. (SUPPLEMENTARY VOLUME,) LONDON LONGMAN, BROWN, GREEN, LONGMANS, & ROBERTS. 1859 QU? CONTRIBUTORS. JOHN ADAMS, Es«. Surgeon to the London Hospital, and Lecturer on Anatomy. ROBERT ADAMS, M.D. Surgeon to the Richmond Hospital, and Lecturer on Anatomy and Surgery, Dublin. B. ALCOCK, M.B. W. P. ALISON, M.D. F.R.S.E. Formerly Prof, of the Pract. of Med. in the Univ. of Edin.&c. JOHN ANDERSON, ESQ. M.E.S. J. APJOHN, M.D. M.R.I.A. Prof, of Chem. in the University of Dublin. VICTOR AUDOUIN, M.D. Paris. Professeur-Administrateur auMusee d'HistoireNaturelle. B. G. BABINGTON, M.D. F.R.S. Late Physician to Guy's Hospital. LIONEL S. BEALE, M.B. F.R.S. Prof, of Physiology in King's College, London. THOMAS BELL, Sec. R.S. Professor of Zoology in King's College, London. CHARLES BENSON, M.D. M.R.I.A. Prof, of Med. to the Royal Coll. of Surgeons, Ireland. *J. BISHOP, F.R.S., London. JOHNBOSTOCK, M.D. F.R.S. (the late), London. W. BOWMAN, F.R.S. Surgeon to the King's College Hospital and to the Royal Ophthalmic Hospital, Moorfields, and late Pro- fessor of Physiology, King's College, London. J. K BOWMAN, ESQ. (the late). Prof, of Practical Chemistry in King's Coll., London. W. T. BRANDE, F.R.S. Formerly Professor of Chemistry to the Royal Insti- tution, &c. J. E. BRENAN, M.D. (the late). W. BRINTON, M.D. Lect. on Physiology at St. Thomas's Hosp., London. W. B. CARPENTER, M.D. F.R.S. Prof, of Med. Jurisprudence, Univ. Coll., London. T. SPENCER COBBOLD, M.D. F.L.S. Lecturer on Botany at St. Mary's Hospital, London. JOHN COLDSTREAM, M.D. Fell. Roy. Coll. Phys. Edinb. &c. W. WHITE COOPER, F.R.C.S. Sen. Surgeon to the North London Eye Infirmary, Ophthalmic Surgeon to St. Mary's Hospital. DAVID CRAIGIE, M.D. F.R.S.E. Fellow of the Royal Coll. of Physicians, Edinb. &c. T. BLIZARD CURLING, F.R.S. Lect. on Surg., and Surgeon to the Lond. Hospital. F. CUVIER, Paris. G. P. DESHAYES, M.D., Paris. A. T. S. DODD, ESQ. (the late). I. DRUMMOXD, M.D., Edinburgh. P. M. DUNCAN, M.D. Physician to the Infirmary, Colchester. II. DUTROCHET, M.D. W. F. EDWARDS, M.D. F.R.S. (the late). H. MILNE EDWARDS, M.D. Prof, of Nat. History to the College of Henry IV., and to the Central School of Arts and Manufactures, Paris. ARTHUR FARRE, M.D. F.R.S. Professor of Midwifery in King's College, and Physi- cian Accoucheur to King's College Hospital. HEINRICH FREY, M.D. Prof, of Gen. and Comp. Anat. at Zurich. R. D. GRAINGER, F.R.S. Lect. on Anat. and Phys. at St. Thomas's Hospital. R. E. GRANT, M.D. F.R.S. L. &E. Fell, of the Roy. Coll. of Physicians, Edinb., and Prof, of Comp. Anatomy and Zoology in Univ. College, &c. W. A. GUY, M.D. Prof. For. Med. King's College, London, and Phy- sician to King's College Hospital. M. H ALL, M. D. F. R.S. L. & E., Lond. (the late). HENRY HANCOCK, ESQ. Lect. on Surgery at, and Surgeon to, the Charing- Cross Hospital. R. HARRISON, M.D. M.R.I.A. (the late), Prof, of Anat. and Surg. in the Univ. of Dublin. JOHN HART, M.D. M.R.I.A. Prof, of Anat. to the Royal Coll. of Surg., Dublin. .A. HIGGINSON, ESQ., Liverpool. J. HUTCHINSON, M.D., London. T. HUXLEY, ESQ., F.R.S., London. ARTHUR JACOB, M.D. M.R.I.A. Professor of Anatomy and Physiology to the Royal College of Surgeons in Ireland. GEORGE JOHNSON, M.D. Physician to King's ColL Hosp., Lond. C. HANDFIELD JONES, M.D. F.R.S. Physician to St. Mary's Hospital, London. T. RUPERT JONES, ESQ. Assistant Sec. Geolog. Soc. London. T. RYMER JONES, F.R.S. Prof, of Comp. Anat in King's College, London. T. WHARTON JONES, F.R.S., London. SAMUEL LANE, ESQ. Lecturer on Anatomy, St. George's Hospital, London. EDWIN LANKESTER, M.D. F.R.S. Lecturer on Materia Medica and Botany. J. LEUCKARDT, M.D., Gottingen. A. KOLLIKER, Prof, of Anat. and Phys. in the Univ. of Wurzbtirg. Right Rev. F. T. MACDOUGALL, D.C.L. Lord Bishop of Labuan and Sarawak, Borneo. BENJ. M'DOWEL, M.D. Professor of Anatomy in the University of Dublin, and Physician to the Whitworth Hospital, Dublin. CONTRIBUTORS, JOSEPH MACLISE, ESQ., London. JOHN MALYN, ESQ. (the late). ROBERT MAYNE, M.D. Lect. on Anat. & Phys. Richmond Hospital, Dublin. W. A. MILLER, M.D. F.R.S. Professor of Chemistry in King's College, London. W. F. MONTGOMERY, M.D. M.R.LA. Fellow of, and Professor of Midwifery in, the King and Queen's College of Physicians in Ireland. GEO. NEWPORT, F.R.S. F.L.S. (the late). R. OWEN, F.R.S. F.G.S. Late Hunterian Professor of Comparative Anatomy and Physiology to the Royal College of Surgeons, London. JAMES PAGET, F.R.S. Surgeon to, and Lect. on Anat. & Phys. at, St. Bar- tholomew's Hospital. RICHARD PARTRIDGE, F.R.S. Prof, of Descrip. and Surg. Anat. King's College, and Surgeon to King's College Hospital, London. BENJAMIN PHILLIPS, F.R.S. London, Surgeon to the Westminster Hospital. SIMON ROOD PITTARD, ESQ. Associate of King's College, London. W. H. PORTER, ESQ. Prof, of Surgery to the Royal Coll. of Surg. in Ireland. G. OWEN REES, M.D. F.R.S. Physician to Guy's Hospital. J. REID, M.D. (the late), Prof, of Medicine in the University of St. Andrews. EDWARD RIGBY, M.D. F.L.S. Late Lect. on Midwifery at St. Bartholomew's Hosp. J. FORBES ROYLE, M.D. F.R.S. F.G.S. Prof, of Materia Medica in King's College, London, H. HYDE S ALTER, M.D. F.R.S. Physician to Charing-Cross Hospital. S. JAMES A. SALTER, M.B., London. HENRY SEARLE, ESQ., London (the late). W. SHARPEY, M.D. F.R.S. Prof, of Anat. andPhysiol. in Univ. Coll., London. JOHN SIMON, F.R.S. Surgeon to, and Lect. on Path, at, St. Thomas's Hosp. J. Y. SIMPSON, M.D. Fellow of the Royal College of Physicians, and Pro- fessor of Midwifery in the University of Edinburgh. SAMUEL SOLLY, F.R.S. Surgeon to St. Thomas's Hospital. GABRIEL STOKES, M.D. J. A. SYMONDS, M.D. Physician to the Bristol General Hospital. ALLEN THOMSON, M.D. F.R.S. Prof, of Anatomy in the University of Glasgow. JOHN TOMES, ESQ. F.R.S. Surgeon-Dentist to the Middlesex Hospital. WM. TREW, ESQ. (the late). W. VROLIK, Prof. Anat.and Phys. at the Athenaeum of Amsterdam. RUDOLPH WAGNER, M.D. Prof, of Anat. and Phys. in the Roy.Univ. Gottingen. W. H. WALSHE, M.D. Prof. Med. Univ. Coll. London, Physician to Uni- versity College Hospital, &c. N. WARD, ESQ. Demonstrator of Anatomy, and Assistant Surgeon to the London Hospital. R. WILLIS, M.D. THOMAS WILLIAMS, M.D., Swansea. W. J. ERASMUS WILSON, F.R.S. Consulting Surgeon to the St. Pancras Infirmary. J. WOOD, ESQ. Demonstrator of Anatomy in King's Coll. Lond., Assistant Surgeon to King's Coll. Hospital. CONTENTS THE SUPPLEMENTARY VOLUME Page Ovum Dr. Allen Thomson 1 Pancreas Dr. Hyde Salter 81 Pelvis John Wood, Esq. ... 114 Reproduction, Vege— | table (Vegetable \Dr. J. B. Sanderson 211 Ovum) J Respiration, Organs of Dr. Thomas Williams 258 Page Stomach and In- ' testine J Sympathetic Nerve ... Dr. Drummond 423 Tegumentary Organs T. Huxley, Esq 473 Ruminantia Dr.T. Spencer Cobbold 506 Uterus and its Ap- "| pendages J Dr. Brinton 293 Dr. Arthur Farre ... 545 SUPPLEMENT. OVUM. — In Animal Anatomy and Physi- ology, the Egg, the product of parental sexual generation, from which the young of animals are produced. The Functions of Reproduction, as observed in the higher orders of animals and in the human species, are generally divided into two classes of processes ; the one of which com- prehends those operations by which the parents contribute to the production of the germs from which the young are formed ; the other, those processes or changes which occur more immediately in the product of genera- tion itself, and which relate to the formation or development of the new being from a germ or ovum. In the Article GENERATION of this Cyclopaedia, the functions belonging to the first of these divisions have been described ; and it is proposed in the present Article to treat of the second class of reproductive phe- nomena, or those which relate more imme- diately to the origin, formation, and growth of the new bettig, and which are usually described under the titles of Ovology, Embryology, and Foetal Development. In this, as in the former article, the history of the functions as they occur in the human species will receive the greatest share of our attention ; but in describing the process of development of the young, still more than in the history of the functions of the parents that are preliminary to the production of a perfect germ, it is necessary to extend our observations to the various members of the animal kingdom, and even in some degree also to plants, from which, as much as from direct observations or experiments in man, has been derived our knowledge of the individual facts and of the general laws relating to the process of embryonic development. The arrangement followed in that part of the article which treats of Development will be adapted more immediately to the consi- deration of human reproduction ; and the statements in regard to animals, or to organ- ised beings in general, will be made chiefly subordinate to, or illustrative of, the functions in the human species ; but the facts in human and comparative embryology are so intimately connected, that it will be expedient to incor- porate with the article such a description of the formative process in different animals as may present a sketch of the general nature of Supp. this interesting process in the whole animal kingdom.* In pursuing this plan, the topics to be dis- cussed may be arranged under the following heads : viz. — Jst. Nature of the Ovum in general, with reference to the different forms of the repro- ductive function in various animals. 2nd. The structure, properties, mode of origin, and formation of the Ovum. 3rd. The changes which the ovum under- goes in the process of Fecundation, and (in so far as the ovum itself is concerned) the cir- cumstances which influence that process. 4th. The external circumstances which in- fluence the development of the ovum and embryo, especially Incubation and Utero- gestation. 5th. The Phenomena of Foetal Development in general, and the history of the origin and development of each system, organ, and tex- ture of the body in particular. 6th. The Functions of the Embryo or Foetus as compared with those of the adult. The wide-spread importance of embryolo- gical anatomy and physiology is now so generally acknowledged by all who have made them a subject of study, that to them no apology is required for the length of this treatise. To those who have not made them an object of their special attention, it will be enough at this place to advert to the exten- sive range of topics which must be embraced in an attempt to trace the history of the first origin and subsequent evolution of all the parts of so complex and various a struc- ture as the body of animals ; and to remind them that this department of science pro- fesses to describe not merely the successive changes of external form and relation by which the several organs, springing from im- perceptible beginnings, arrive at their perfect condition, but also the more minute pheno- mena of histological development, or changes of the several textures, which accompany the more obvious formative processes ; that, as in many instances the complete knowledge of * It was originally intended to have treated in the same article of the embryology of plants ; but the extent and importance of that subject in con- nection with general physiology makes it necessary to postpone its consideration to a separate article, under the head of VEGETABLE OVUM. it OVUM. the 'stract are nv.d funcricvn r,f ah organ is only to be obtained by the observation of its foetal conditions, the study of development is acces- sory or supplementary to many departments of anatomy and physiology ; that, in recent times, no branch of inquiry relating to organic nature has made more rapid progress, has presented a greater amount of new dis- coveries, or has influenced in a greater degree the views of scientific men on allied subjects, than the science of embryology ; that it is coextensive with, and illustrative of, the whole range of comparative anatomy; that no system, therefore, of zoological classi- fication can be regarded as philosophical or complete which neglects the facts and princi- ples of foetal development : finally, that some departments of pathological anatomy receive considerable illustration from our science, and that more especially the scientific study and comprehension of teratology or congenital malformations is founded entirely on an accu- rate knowledge of the phenomena and laws of development. Our subject, therefore, is not only interesting by itself, but deeply important as an essential branch of philosophical ana- tomy and physiology.* Before proceeding with the particular his- tory of the ovum, and its development in man and the higher animals, which will form the greater part of the following article, some topics of a general and preliminary nature present themselves for our consideration. The investigation of the process of repro- duction in the lower animals has made so much progress during the last few years, that it becomes necessary to place before the reader a sketch of the aspect in which more modern researches enable the physiologist to view the relation of the ovum to the sexual generative function, and to the other means by which individuals are multiplied, or species are reproduced in the whole animal kingdom. In the Article GENERATION, the commonly received distinction was drawn between the sexual and the non-sexual modes of genera- tion ; and under the latter form a variety of processes of Gemmation and Division were alluded to as occasional or constant substi- * A variety of circumstances have contributed to cause delay in the appearance of the present article, some of them of a nature beyond the con- trol of the author. He is sensible, however, that an apology is due by him to the readers of this work on account of the protraction of that delay. He has only to say, that in the contemplation of the vastness and imperfectly known condition of the subject, he has ever felt more disposed to engage in the investigation of some of its details, than to appear before the public as a systematic writer in regard to it. The delay may have this advantage, however, that it will enable him to in- troduce a greater number of new discoveries, a more accurate statement of individual facts, and more correct and extended general views of the subject than might have been possible at an earlier period, and that it will afford him an opportunity of cor- recting and amplifying various statements con- tained in the previous Article GENERATION, which the progress of discovery since the time of its pub- lication has rendered necessary. tutes in a certain number of animals for the more permanent sexual form of the reproduc- tive process. At the time of the publication of that article, the sexual organs had not been discovered in a considerable number of the lower animals : but since then, the assiduous and accurate researches of embryologists have gradually diminished the number of animals so situated, by bringing to light the male and female reproductive organs, or their essential products, in nearly every species of the animal kingdom ; so that now only a very few, and those of the simplest organisation, remain, in which the bisexual condition has not been detected. These animals belong exclusively to the division of the animal king- dom recently established by Zoologists, as Protozoa, comprehending the Polygastric In- fusoria, Rhizopoda and Porifera.* In all other animals it is now ascertained that fecundated ova, formed by an act of sexual generation, are the means of securing the permanent reproduction of the species ; but in several of them, as is especially well known among the Polypine tribes, a vast multiplication of individuals, sometimes living separately, but more frequently associated in groups, or living in united colonies, takes place by a non-sexual process of reproduction, which may be compared in many instances to the growth or repetition of the parts of a tree or plant by budding. Recent investigations have made it more and more apparent, that the non-sexual multi- plication of animals ought to be distinguished into several kinds, according to the different circumstances in which it may occur. In a few, as already remarked, it is entirely with- out known sex : in others, the non-sexual pro- cess of gemmation, or division, gives rise to new individuals, which are simply the repe- titions of the perfect or complete animals ; and in a third set, the non-sexual multiplication occurs more frequently in an incomplete con- dition of the animal, and often consists in the production of one or more series of dissimilar forms of animals, the last generation of which alone becomes sexually complete, and propa- gates the species by fecundated ova. This constitutes the variety of the reproductive process recently distinguished by the name of Alternating Generation. Three forms, therefore, of non-sexual animal reproduction, or multiplication, are to be dis- tinguished from the sexual mode of generation, as in the following enumeration : — I. True sexual generation, direct or indi- rect, in all animals, excepting the Protozoa. II. Non-sexual multiplication, occurring only in some of the invertebrated animals ; 1st. In Protozoa, in which sexual organs have not yet been discovered. * The first two of these divisions maybe described as simple unicellular microscopic animalcules, the third rather as a compound or congeries of micros- copic animalcules : the Porifera, or Sponges, are in- cluded in this division of Protozoa, because the balance of evidence is decidedly in favour of their animal nature. OVUM. 2nd. In Animals known to be capable of s-xuul generation ; including two varieties, viz. a. Multiplication of similar individuals, either in a mature or immature condition. I). Multiplication of individuals, generally dissimilar from those producing them, and becoming at last mature or complete in the exercise of the true generative function. Some account of these various forms of the reproductive process, and especially of the last, as established by recent discovery, sup- plementary to that contained in the Article GENERATION, may be introduced here, with a view to serve as a foundation for general views of the nature of the ovum, and its relation to the reproductive process in ge- neral. I. OF THE OVUM IN GENERAL, AS RELATED TO THE SEXUAL PROCESS OF GENERATION. The term orum is in this article entirely restricted to the product of sexual genera- tion. This body is formed in the ovary of the female parent (or in the female organ of a hermaphrodite parent) by a graduaf process of growth or development. When it arrives at a state of maturity, it is spontaneously dis- charged from the place of its formation, a process which in the higher animals has re- ceived the name of Ovulation. If left to its own unassisted powers, no organic change of importance follows in the ovum, and it remains incapable of producing an embryo. But if, at or near the time when the ovum, in a state of maturity, leaves the ovary, it be sub- jected to the influence of the male product or sperm by the contact of a very minute portion of that substance, it then undergoes the change of Fecundation, by which it has communicated to it the power of having de- veloped within it a new being specifically resembling its parents. Although there are many great apparent differences in the form and structure of the ova of animals*, yet a general comparison of their organisation shows that they consist in nearly all of parts that are essentially the same. These parts in the ovarian ovum are the following, beginning with that which appears most essential : 1st, The Germinal Vesicle, or Germ-cell; a nucleated organ'c cell of microscopic size, generally situated near the surface of the ripe ovarian ovum : this is embedded superficially in, 2nd, The Vitelhis, Yelk) or Yolk, a mass of oleo-albu- minous matter, partly fluid, and partly cellular and granular, generally of propor- tionally much greater size than the germ-cell, and serving to furnish materials for the changes of that body, and for the develop- ment of the new being. Both of these parts are enclosed by, 3rd, The ViicUine, or Yolk- Membrane, a vesicular, nearly structureless, membrane, which contains the rest, and gives to the whole usually more or less of a sphe- rical form. To the assemblage of these parts, constituting the ovarian ovum, and which may be looked upon as most immediately im- portant in connection with the formative pro- cess, there are generally added, after it has left the ovary, and in the progress of its descent through the female passages, some others, such as the albumen, outer membrane and shell of the bird's egg. In their simplest form these additional parts constitute an ex- ternal covering of the egg, to which the name of Chorion is often applied. If the ovum be traced back to its earliest origin in the ovary, it is found to consist at first of the germinal vesicle, germ-cell or its nucleus (Jig. 1, c.). To this cell the sub- stance of the yolk is added in the progress of its formation, generally in a gradual manner, but in some animals more suddenly. Fig. 2. Ovarian Ovum of a Klammifer. a, entire ; 6, burst, showing1 the germ-cell, with yolk granules flowing out of the vitelline membrane ; c, the ovarian ovum at an early stage of its formation, consisting of the germ-celf surrounded by a few yolk granules. * The most important of these will be noticed in ft later part of the article. Spermatic Filaments (From P. Wagner and LeuchliardC). a, spermatozoa of the squirrel. 6, spermatozoa of the dog, in the interior of the developing cell. The Spermatic Substance, or Sperm of the male, when examined in its state of maturity, as it is applied to the ovum, and effects in it the peculiar change of fecundation, is observed to consist essentially of an immense number of minute bodies, generally consisting of a thicker particle, with a fine filament attached, B 2 OVUM. and almost always exhibiting, when recently mixed with water, vivid vibratory or undula- tory movements, but in a few animals present- ing other forms, and without motion. rri " cells, which are descended from the original embryo-cell. From this blastodermic mass or membrane, These the embryo, or foetus, or new animal, and in spermatic filaments or particles are developed the higher animals some accessory parts by a peculiar process in the interior of the which are temporarily united with the embryo * ,, } •• • . i i . , i*,ii- * /M i .• 4-^k ifo I \ivfn rMMonneif'^ jin/i avr* CTTJI — cells (sperm-cells) secreted in the male organ or testis. When the ovarian ovum has arrived at maturity, the germ cell disappears as such, and if fecundation shall have taken place, that vesicle is succeeded by another minute cell, with which the origin and development of the new animal are most intimately associated. This secondary organic cell of the fecundated ovum has therefore been called the Embryo- cell. The first changes, preparatory to the commencement of the development of an embryo, consist in the formation out of the embryo-cell and yolk substance of an organised cellular mass, or of a membranous covering of the whole qr a part of the yolk: this is the germ-mass, Blastoderm, or germinal membrane, Fis. 3. cJio Fecundated Ovum of a Mammifer, with the Embryo Cell and its division. a, ovum with the first embryo-cell ; b, division of embryo-cell and cleavage of the yolk round it ; c, second division and cleavage ; d, farther division ; and e, germ-mass or Blastoderm forming ; /, dia- gram of the embryo with its membranes, the am- nion, allantois, &c., within the chorion. The process by which this primary organised part is produced varies somewhat in different animals; but it appears to consist in a mul- tiplication of the embryo-cell by changes of the nature of cytogenesis, accompanied with more or less of a cleavage or sub-division of the substance of the yolk, and its com- bination with the progeny of the embryo-cell. The general result is, that the first rudiments of the new being take their origin in organic previous to its birth, originate, and are gra- dually formed, by a various process of pro- gressive organic growth of an epigenetic character, which is termed Development, or Embryo-genesis. In by far the greater number of animals an ovum gives rise to only one embryo or indi- vidual, and this one becomes by itself, when its growth is complete, the perfect sexual animal, capable of contributing its share to the pro- duction of fecundated ova. But in a certain number of animals, to which allusion will be made more fully afterwards, the immediate product of development from the ovum is not at once, and by itself, converted into a com- plete sexual individual ; but by an intermediate non-sexual process of production, one or more new individuals are formed out of the body of that first developed, and to the last so formed is committed the office of sexual reproduction, or true generation. The essential conditions and phenomena, therefore, of the sexual process of generation, as related to the ovum, and as limited by the foregoing considerations, may be shortly stated to be the following; — 1st. The formation of the ovarian ovum of the female sex, containing the germ-cell. 2nd. The formation of the sperm-cells of the male sex, and the development of their peculiar spermatic elements. 3rd. The mutual action of these two pro- ducts in the fecundation of the ovum. 4th. The disappearance of the germ-cell of the ovarian ovum, and the formation of the embryo-cell in the fecundated egg. 5th. The multiplication of the embryo-cell by cytogenesis, and the formation from that body, and from the yolk, or a part of it, of the blastodermic mass or membrane. 6th. The process of embryo-genesis, or development of the systems, organs, and textures of the new animal. It is right to state that the original germ- cell has not yet been ascertained to exist in the ovum of every animal, nor has its successor, the embryo-cell, been observed in all instances ; but they have been detected in so very large a proportion, that it appears extremely pro- bable that in all sexual animals the generative process consists in the process above described, or in some modification of it. I refrain at present from farther details as to these phe- nomena, and have stated the results only in their most general form, because I shall have occasion to return upon some of them in a subsequent part of the article. Looking back on this general statement of the com- mencement and progress of the genetic process in animals, it will be seen that the new being may be considered as taking its immediate origin from the progeny of cells descended from the embryo-cell. That OVUM. cell appears with great probability to take its origin from the germ-cell, or its nu- cleus, or from some part of it, in combination with a determinate portion of the sperm product, or descendent of the sperm-cell ; and we are so far justified, therefore, in ascribing the genetic process by which the new being is formed to the mutual action of the products of two different kinds of cells, viz., the germ- cell and the sperm-cell. * In conclusion, the ovum may be defined to be a distinct vesicular body originally formed from a ce 1, presenting throughout its exist- ence the organic cellular structure, consisting of oleo-albuminous materials, formed by the female of an animal species, and capable, when acted on by the spermatic product of the male, of undergoing the successive changes of embryo-genesis, by which, either directly or through intervening generations, the species of animals is reproduced and continued. The structural distinctive characters of an ovum are, therefore, its enclosure within a distinct vesicular covering, and its original organic cellular constitution in the germ-cell : its most important physiological characteristic is its susceptibility of the changes of embry- onic development under the influence of the sperm-cell or its product. II. OF THE NON-SEXUAL MODE or GENE- RATION. The necessity of distinguishing several kinds of non-sexual reproduction according to its occurrence in animals entirely without sex, or believed to be so, and in those which mav also be propagated in the sexual mode, has already been adverted to. A farther distinc- tion of the non-sexual reproduction may be made according to the nature of the process itself: thus, some forms of it consist in the development of buds, so intimately united with the parent substance, that scarcely any difference can be perceived between their mode of formation and that of continuous growth, as in Hydra and various Polypes : other forms consist in the development of new individuals from germs so isolated in their form and cellular in their structure, that it might seem at first sight arbitrary to distinguish them from ova, as in Aphides ; others appear to hold an intermediate place and character between these two forms, as in ISalpa: while, in a fourth set, a more complex and varied series of changes occurs, which may be regarded with probability as modifications of the gemmal or germinal processes, as in Medusoid Polypi, Taenia, &c. But it will be apparent from what follows that we are as yet very far from that exact knowledge of the nature and first origin of buds, gemmae, or other kinds of germs, from which animals may be multiplied in the non-sexual modes, which would enable us to form satisfactory general * These views have been stated with great clear- ness by Prof. Owen in his various writings, especi- ally in his Essay on Parthenogenesis, and Lectures on Generation, &c., in Medical Times, 1849, and by Dr. Carpenter in his Principles of Physiology, Ge- neral and Comparative. 1851. conclusions as to their mutual relations, and their similarity or difference, as compared on the one hand with organic growth, and on the other with oval development. As the accurate determination of these re- lations is in a great measure impossible, it will be expedient for the present to state only very briefly the general characters of the several non-sexual modes of reproduction, before selecting for more particular consider- ation some varieties of the process, the recent investigation of which seems calculated to influence in a considerable degree future ge- neral views of the whole subject of reproduc- tion. We shall also defer for the present any minute consideration of the relation of these processes to the growth or development of cells, for we shall have occasion to treat more at length of that subject in a subsequent part of this article, and in that of vegetable ovum.* At this place it is only necessary to re- mind the reader, that all processes of develop- ment, whether in the earliest or at more ad- vanced stages of formation, appear to consist essentially in, or are more or less intimately connected with, a multiplication of organic cells in the parts that are developed. In the unicellular beings, fissiparous and gemmiparous multiplication may easily be recognised to be processes of cell growth ; the one consisting in the division of the parent cell into a pro- geny of two by a nearly equal partition of its substance ; the other, in an extension and gradual enlargement of a small or limited por- tion of the original cell. But in many of the instances of fission and gemmation on the larger scale with which we are acquainted, observa- tion has not yet pointed out the primary cell, if it exists, from which the process of division or extension begins jand,indeed, most instances of fissiparous division may. as Dr. Carpenter has remarked, be referred to a peculiar modifi- cation of gemmation. The process of budding or gemmation is usually stated to occur in one of two modes. 1st, by the extension of a part of the parent body which remains in organic connection with it during the development of the new individual from the bud ; the attached bud either sprouting from the exterior, or being developed in the interior of the parent stock. 2nd, by the development of the new individual from a small detached portion of the substance of the parent, which undergoes the principal formative changes after its separation. These separate buds have been called gemmae, gem- mules, bulbils, &c., and two kinds of them may also be distinguished according as they are thrown off from the external surface of the parent body, or are formed and become loose within its interior. These gemmules have frequently attained to some degree of development by the time of their separation, and very often are provided with cilia over their surface, which cause them to move * For a very lucid and agreeable statement of these relations the reader is referred to Dr. Carpen- ter's able Treatise on General and Comparative Phys'.ology. 1851. B 3 OVUM. rapidly through fluids. From the first they exhibit a minutely cellular and granular struc- ture : but it does not appear that they are originally formed from any single nucleated cell : they appear rather from the first to he a congeries of cell progenies. They are desti- tute of an external envelope ; hut, nevertheless, it may often be difficult to distinguish between them and true ova. The tendency to the multiplication of indi- viduals by non-sexual reproduction is greatest among those animals which are of the simplest organisation, and more especially among those in which the cellular structure predominates; not that it is confined to them, nor that it occurs in all animals so constituted, but that it is much more frequent and complete in the simplest animals of each class in which it has been observed ; as if it were more liable to occur in those species in which the process of individual development had proceeded to the least extent of advancement in the formation of the living textures of their bodies. There is accordingly a remarkable similarity in the nature of the processes of non-sexual multi- plication and ordinary growth in these very simple animals j and it is well known that the same relation subsists between a low organi- sation of animals, and their disposition or power to repair individual parts of their bodies lost by injury or accident.* 1st. Of the Process of Reproduction in Pro- tozoa, or animals in which the sexual distinction has not yet been discovered. Among the Protozoa reproduction takes place in two modes, viz., 1st, by the process of gemmation or fission, and, 2nd, by develop- ment from separated gemmules or germs. For an account of the first of these processes, the reader is referred to the articles POLYGASTRIA and PoRiFERA.-f- Among the Polygastria multiplication by division is much more frequent than that by gemmation. It consists in the fission or di- vision of the whole unicellular body into two nearly equal parts, each of which becomes, when separate, a perfect animalcule like the original one : in some the division is trans- verse, in others longitudinal, and occasionally it occurs in either of these modes in different individuals of the same species. The nucleus of the unicellular polygastria has been fre- quently observed to undergo division previous to the formation of the fissure, by which the division of the external wall is completed. — a fact which has led some physiologists, as Ehrenberg, M. Barry, and Owen, to attribute to the nucleus an important influence in this process of cleavage ; the first of these ob- servers having even conceived the nucleus to act the part of a male or fecundating organ. * See Mr. Pagefs recent interesting lectures on this subject, published in Medical Gazette, 1849. f A considerable number of the poly gastric infu- soria described by Ehrenberg in his great work on that class, are now very generally regarded as be- longing to the vegetable rather than to the animal kingdom, such as the families Closterina, Volvocina, and Bacillaria. This latter view is not, however, adopted by many of those who have made a study of this class of animals. In some of the polygastria in which the process of multiplication is either of a fissi- parous or gemmiparous kind, as in Vorticella, Uvella, and Polythalamous llhizopoda, the new individuals remain in connection, and are associated together in branched pediculated groups, in connected masses of a globular form, or in regular spiral united series.* The Porifera, or sponges, appear to be re- produced by a different kind of gemmation from that now described in polygastria, — viz., by separate gemmules or small portions of the substance of the sponge, which, soon after having been detached from the main stock, are moulded into a spherical form, and, being pro- vided with cilia, move about in the water with great vivacity for a considerable period. These gemmules are thrown off in numbers propor- tional in some measure to the activity of the nutrition of the sponge, and therefore princi- pally during the early part of summer. Towards the approach of winter a different kind of re- productive bodies is observed to be formed, — viz. small capsules containing globular germs, which, after development within the capsule, pass out of it and produce a new sponge for every capsule or germ. These bodies have been called ova, and certainly they bear very great resemblance to them ; but too little is known of their nature and origin to enable us to form an opinion whether they are to be regarded as precisely of the same nature as ova or not. In the mean time they may be named the capsular germs.'j' But it appears that, among the polygastria, and rhizopoda also, there are sometimes formed, by a peculiar process not ascertained to be of a sexual kind, minute reproductive bodies of a cellular structure, which, if they are not true ova, are at least substitutes for them.f * See an interesting paper by Dr. Carpenter on the Genus Nummulina and other Foraminifera in Quart Journ. of Geol. Soc. Feb. 1850. Some ju- dicious and interesting remarks on this class of animals, and on the relations and characters of the Protozoa in general, are contained in a recent paper by Mr. Huxley in the Annals of Natural History (1851, vol. viii. p. 437.), in which he has described a curious monocellular genus named Thalassicolla, •which occurs in masses, and forms spicula some- what like a minute sponge. f See Laurent's elegant memoir, Recherches sur 1'Hydre et 1'Eponge d'eau douce. 1842. J Allusion is not made here to the production of granules by the diffluence of an infusorian animal- cule erroneously taken by Ehrenberg for the depo- sition of ova, but to a very different process. Du- jardin, who pointed out this error (Hist. Nat. des Infusoires, p. 101.), is of opinion that, besides the processes of fission and gemmation, we know nothing with certainty of the reproduction of infusoria ; but he admits that it is possible that the minute bodies into which an infusorian breaks up by diffluence might prove the germs of new individuals. Dr. Carpenter has mentioned several instances of a kind similar to those alluded to in the text, and has expressed the opinion that something of the nature of sexual pro- duction may yet be discovered to take place in these animals (Prin. of Gen. and Com p. Physiol. p. 240, and p. 917.). Observations of a similar kind are re- OVUM. Some recent observations appear to throw additional light on this subject, and to make it probable that in some circumstances this process is in some sort analogous, or at least equivalent, to one of sexual reproduction. The first accurate observation of the de- velopment of a progeny of young cells within the body of a polygastrian was communicated by Focke in 1844 to the meeting of natu- ralists at Bremen, and the fact of the pro- duction of internal germs or bodies resembling ova or spores within the body of these ani- malcules has recently received full confir- mation from the observations of Stein and of Cohn.* In Cohn's observations, which were made on a parauiaecian polygastrian, the Loxodes Fig. 4. formation and extrusion of ova or germs in Loxodes lursaria {from Cohn). a, animalcule, containing two young; b, contain- ing six ; c, one of the embryos escaping ; d, e, two ciliated embryos. bursaria, which is usually multiplied like the rest, in the fissiparous mode, sometimes by longitudinal, at others, by transverse division, it was found that at certain periods there were formed within the bodies finely granular colourless cells, in some only one, more fre- quently several, and occasionally as many as six or seven, nearly of a uniform size, and ferred to under the head of ' sporiferous reproduction,' by Prof. Rymer Jones, in the article POLYGASTIUA. * Stein, "Untersuch. lib. die Entwick. der Infuso- rien, Wiegmann's Archiv., 1849, vol. 1. p. 134. in Ac-tinophrys, Acineta, and Chilodon uncinatus. Cohn, in Zeitsch. fiir Wissensch. Zoologie, Xov. 1851, p. -2-J-. each presenting two contractile vesicles like the parent. The escape of these bodies, by their passage through an aperture temporarily formed in the wall of the infusorian, was carefully observed ; the exit of each embryo occupied about twenty minutes. Soon after their escape they exhibited active ciliary mo- tion, and moved about with all the appearance of embryo-infusoria. Although the farther development of these bodies was not traced, the observations on this animal, and on an- other, the Urostyla grandis, afford sufficient proof that the infusoria may be propagated by minute separate germs, as well as by division of their bodies. A similar production, but more numerous, of an internal progeny, has been observed in the microscopic parasitic animalcule termed Gregarina, which infests the intestinal canal of a number of insects, earth worms and some other invertebrate animals.* The simple Gregarina consists of a single cell filled with granular substance, and con- taining a distinct nucleus. It has no intestinal canal, nor other internal organisation ; is gene- rally of an elongated shape, and creeps about by motions of slow contraction of its substance. The formation of the progeny or smaller bodies within the Gregarina is attended with a remarkable change in the parent animal, which has been carefully observed by Stein. This change, in which the animal appears double for a time, had been previously no- ticed by Kolliker and others, and had been interpreted by Kolliker as the conversion of a single animal into two, by a process analo- -F/g. 5. GregarnuE {from Kolliker.) a, single; 6, c, d, united ; e,f, g, the formation of the navicella-like progeny ; h, three of these ua- viceliae (from Stein). * These animals were first accurately described by Leon Dufour in 1837 (Ann. des Sc. Xat. vol. vii. p* 10.). They have since been studied with great B 4 OVUM. gous to transverse fission. Stein, on the other hand, has been convinced by a very at- tentive observation of the different stages of this process, that it is of an opposite character, and that, previous to the development of the young progeny, two of the Gregarinae have become fused, or united into one. As the two are about to unite, they gradually change their form from that of elongated plana/ia- like animalcules, to that nearly of hemispheres, closely pressed together ; then a complete fusion or union occurs, and the whole of the granules of both having become amalgamated in one sphere, the development of the internal progeny takes place gradually from the mass. This progeny consists in a vast multitude of minute bodies, shaped like the Navicellae (among the Diatomaceae), but different from these bodies, and very probably constituting the reproductive germs or embryos of Gre- garina?. The development of this Navi- cella-like progeny into the Gregarina does not appear as yet to have been traced ; as in this animal, like many other parasites, the progeny is required to migrate during its de- velopment from one stage to another, and the little bodies are passed out of the alimentary canal of the insect before undergoing farther changes. The views and observations of Stein, how- ever, should they be confirmed by others, would prove the very remarkable fact, that the phenomenon of conjugation, or fusion of two unicellular individuals, hitherto supposed to be confined to some of the simpler plants, as Closterium, Spirogyra and Zygnema, &c., may occur also in animals of a similar simple structure. These observations on the Gregarina are not altogether of an isolated kind. In a recent interesting notice of this subject by V. Siebold *, he has called attention to the ob- servation of Kolliker on the conjugation or fusion of two individuals of Actinophrys -{-, a spherical infusorian animalcule analogous to the Amoeba or Rhizopoda, by its slowly con- tractile, amorphous texture, and its long, ra- diating, contractile processes. Kolliker ob- served two individuals of this animalcule to approach each other, adhere, and gradually to fuse into one, which soon assumed the same globular form, with the radiated contractile processes, as each of the two that formed it, and differing only from them by the increase success by various observers, as V. Siebold (Beitrag. Z. Naturgesch. Wirbellos. Thieve, 1839, p. 63.'). Henle (Muller's Archiv, 1845, p. 369.), and Stein in the same, 1848, p. 182. Kolliker (Zeitsch. f. Wiss. Zool. 1848 and 1849), and as many as eighty dif- ferent species of them have now been discovered * Zeitsch. f. Wissensch. Zool. March, 1851, p. 62. f Op. cit. 1849, p. 207. In this very interesting memoir Kolliker has proved the animal nature of the Actinophrys by his observations on its contrac- tility, and on the manner in Avhich the particles of solid matters, vegetable and animal, are involved in its substance for the purpose of digestion, and their remains again rejected when that process is com- pleted. of size which it sustained. This very curious observation has been confirmed by Stein, in an allied genus Podophyra, both of the sessile and pediculated kind ; and V. Siebold has ob- served the same phenomenon in a species of Acineta belonging to the same family of Infusoria. Cohn, also, has repeated and con- firmed Kolliker's observations in the Acti- nophrys sol, and has made a farther discovery of great interest in connection with the pro- cess of conjugation in these animals, having observed after the union, both in the Acineta and Actinophrys, the development, at certain periods, between the united individuals, of a spherical body of considerable size, vesicular form, and containing within it a nuclear forma- tion of variable magnitude. Although the farther development of this body has not yet been traced, it seems not improbable to V. Siebold that it may be analogous to the reproductive capsule or sporo-cyst of the conjugating Closterium or Zygnema*, from which bodies it seems to be certain that a number of reproductive spores are produced. Since the foregoing was written, indeed, renewed researches by Stein -j- have come under my notice which are confirmatory of the view previously stated as to the repro- ductive process in Gregarina, and explain in a great degree the apparently incomplete observations of Pineauj and others as to the varying conditions of Vorticella, and also extend our knowledge of the production of germs of the Infusoria. Stein observed the Vorticella microstoma to lose its pedicle, become free, assume the globular form, and at last to be enclosed in a cyst produced by exudation from its own body. After a time the band-like nucleus of the encysted Vorti- cella is divided into a number of small discoid bodies, not by a regular or progressive process of cell-cleavage, but at once and directly. These minute bodies gradually increase in size at the expense of the granular and fluid substance surrounding them in the cyst, and ultimately escape in the form exactly of Monas colpoda (of Ehrenberg). These very soon fix themselves ; and a fine pedicle is developed at the place of attachment. In other instances the Vorticella-cyst was observed to send forth long contractile processes from its sur- face, and then assumed very much the form and appearance of an Acineta or Actinophrys; and in this case a new Vorticella was formed in the interior in the manner of a bud. The Vorticella, therefore, it would appear, is ca- pable of reproduction in two modes, — by the development of embryoes from the divided nucleus, which Stein on this account proposes to call nucleus germinativus (the testis of Ehrenberg) ; and by gemmation from an intermediate Acineta form. The first form Stein would regard as the equivalent of sex- * See the Article VEGETABLE OVUM for an ac- count of this process in the lower forms of plants, t Zeitsch. fur Wissensch. Zool. Feb. 1852. j Ann. dcs Scien. Nat. 1845 and 1848. OVUM. ual production ; the second as coming under the category of alternate generation ; and the Vorticella embryo of the Acineta-form either repeats its gemmal multiplication, or becomes encysted, and gives rise then by its nuclear division to embryonal production. Other new forms of Infusoria are described by Stein under the names Spirochona gemmipara, Dendrocometes paradoxus, and Lageno- phrys vaginicola, ampulla, and nassa, in which the mode of reproduction is somewhat similar. These observations at once show the im- portance of the views entertained by some authors as to the share the nucleus may take in new production, and strongly indicate that much still remains to be known from ob- servation of the processes of reproduction among the Infusoria. Should these observations be confirmed, another analogy, in addition to those already observed, will be shown to exist between the organisation and functions of the Protozoa, and those of the lowest plants.* The ten- dency of various other recent researches, to which it has been impossible to refer more particularly in this place, seems to be to show that, in addition to the more common and obvious mode of multiplication by division and gemmation, by which the Infusoria, when vigorous and well nourished, are reproduced, there are other means by which, in dif- ferent circumstances, the more permanent re- production of the species may be secured; that minute cells are formed within them for that purpose, which may at present be called reproductive cell-germs rather than ova, till a more complete knowledge shall have been obtained of their nature and of the circumstances attending their formation ; and that it is very probable that in the protozoa, as in the simplest plants, the com- bination of the contents of two cells, to all appearance similar, may, as in the process of conjugation, be the necessary preliminary step to the development of the reproductive germs. It ought at the same time to be kept in view that the Infusoria may, like many other animals, be subject, some to metamorphosis, and others to alternate generations. Already, since the publication of the great work of Ehrenberg, most important modifications of his system of these animals have been found necessary, and it seems almost certain that it is destined to undergo still farther changes, many of those forms which are now recog- nised as belonging to distinct genera and species being possibly no more than different stages of development of the same animal. 2nd. Of the possibility of primary r, direct, or non-parental production of animals, or of so- called spontaneous and equivocal generation. From what has before been stated as to the very general, and almost universal, existence of the sexual mode of generation among ani- mals, and from the reasons that have been given for the belief that in those few and simple animals in which a sexual distinction * See the recent work of Alex. Braun, entitled Die Verjungung in der Xatur, Freiburg, 1849. has not yet been ascertained, there may still be propagation by means of minute germs, the reader will already have drawn a con- clusion as to the very' in sufficient nature of the proof that can now be adduced in favour of the view that certain animals may arise independently of pre-existing individuals of the same species. The hypothesis might, per- haps, be at once dismissed with the remark of a recent writer*, " that it is safer to trust to generally prevailing laws, than to confide in such of our observations as are contrary to them." But as in the article GENERATION f, the author was led by a careful examination of the evidence then available on the subject, to admit the probability of the non-parental mode of production as an exceptional occur- rence, at least among the lowest tribes of animals and plants, and as that hypothesis has since gradually lost more and more of its pro- bability, from the accumulated opposing proofs resulting from more recent researches, so as, in his opinion, to be now no longer tenable, it may be proper at this place to review briefly the bearing of the present more advanced knowledge "of the generative process upon this long and keenly debated question. Admitting, in the meantime, that the ova, or separate germs of Infusoria, have not yet been discovered with certainty, there are not wanting direct experiments which demonstrate that in an infusion of organic matter which would, when exposed to the air, naturally furnish a rapid succession of these produc- tions, the development of living organisms is entirely suspended, if the arrangements are made such as to render it impossible for any germ or other part of a previously existing infusorian animalcule or plant to be communicated to the infusion. The experi- ments of Schultze and of Schwann are valuable, as appearing to have secured, in a great measure, the above-mentioned con- ditions, without otherwise interfering with the validity of the result. The first of these ob- Fig.6. Apparatus employed by Schultze to prevent the access of germs by the air to an infusion. a, flask for infusion ; b, tube, with caustic potash ; c, tube, with sulphuric acid. * Eschricht, in Edinr. Xew Phil. Journ. vol. xxxi. 1841. p. 355. t P. 42U. 10 OVUM. servers* placed in a glass flask an infusion of organic matter, a portion of which was known from comparative trials, when left exposed to the open air, soon to have animalcules deve- loped in it in great quantity, and he connected this vessel with a tubular apparatus, by two apertures, in such a manner that the air, which was made to pass frequently through the vessel containing the infusion, should be drawn through strong sulphuric acid, or potash solu- tion, before reaching it ; and Schwann | ar- ranged a similar experiment, having in view to secure the like conditions, by causing the air, which had access to the infusion, to be pre- viously passed through an iron tube at a red heat. Before the commencement of these experiments, the infusion and the apparatus were carefully subjected to the temperature of boiling-water, by which it was presumed the vitality of all ova, or germs, or other or- ganic particles must have been destroyed : and the result was the same in both the series of experiments, — viz., that, after a consider- able lapse of time, no animalcules nor con- fervoid plants were formed : but when the atmospheric air was afterwards allowed to pass freely over the same infusion, without being subjected to the processes before men- tioned, a rapid production of infusory ani- malcules took place in the usual manner. The results of these experiments appear to be on the whole satisfactory, and nearly to decide the question as far as relates to the probability of the introduction of the germs of Infusoria, &c., into infusions by the air. But, indeed, the failure of many experiments of this kind, when not performed with the most scrupulous accuracy, need not excite surprise, when the very indestructible nature of some kinds of infusory animalcules is con- sidered. It has long been known, and has been ascertained by the careful experiments of Spallanzani, Bauer, and Doyere, that some of the Rotifera and Tardigrada are capable of supporting a high temperature without loss of life, and of being kept for years even in the state of complete dryness, without loss of vitality : and, although it must be admitted that these animals differ greatly in their or- ganisation from the Polygastric Infusoria, and the latter appear to be very liable to destruc- tion from slight causes, yet it is possible that their germs may resist destruction in a greater degree than their adult forms : and, should only one of these animalcules, or its germ, be left in any situation favourable to its development, it is easily understood, from what is known of the production of these beings, with what rapidity a vast multitude of them may be brought into existence by their ordinary process of fissiparous increase. Most physiologists are inclined to reject as fanciful and inaccurate the alleged observa- tions of the actual conversion of particles of organised or organic matter into living in- * Poggendorff's Annalen, 1837, and Edin. New Phil. Journ. vol. xxiii. p. 165. t In paper on Fermentation, &c. in Poggen- dorff's Annalen, 1837, p. 184. fusoria. At all events, statements of this kind are to be received with the greatest caution : such, for example, as the observa- tions stated to have been made by Pineau*, who affirms that he has seen the direct con- version of particles of disintegrating muscular fibre, isinglass, and wheat-flour, into various forms of living infusoria. The spermatic filaments also, which, so long as they were looked upon as independ- ent animals, were referred to as examples of an undoubted spontaneous generation, furnish no evidence in favour of that hypothesis in the view in which they are now regarded by physiologists : for they are to be considered rather as a peculiar product of organic growth within the spermatic cells, somewhat ana- logous to the fine moving processes of the ciliated texture, than as distinct organisms, -f- In so far, therefore, as the theory of spon- taneous generation may have been supposed to derive support from the formation of the lower forms of plants and animals in infusions of organic matter, that hypothesis must be considered as having lost the greater share of its probability, if, indeed, it has not been entirely disproved : but it must at the eame time be admitted that a more precise ac- quaintance with the nature of the germs from which these organisms take their origin is still required to render the arguments derived from this source entirely conclusive.^ The external and internal parasites which infest the bodies of almost all animals have in former times been held to afford a still stronger presumption in favour of sponta- neous generation than the production of in- fusoria ; but it will be found that in this instance, to a much greater extent than in the other, the probability of the view has gradu- ally passed away before the increasing know- ledge which modern research has afforded of the various modes of propagation of these animals. The ready communication of various Epi- zoa, or external parasites, from one animal to another is now well known, and accurate ob- servations have demonstrated that in almost all instances this communication may be traced to the implantation of ova, or pregnant individuals into their parasitic abode, as in the researches on the Sarcoptes scabiei, &c. The parasitic fungi, also, of various cuta- neous diseases, as tinea, porrigo, plica po- lonica, foul ulcers, &c. ; the yeast-plant, the vinegar-plant, and other minute fungi con- nected with fermentation ; the contagious algas of the batrachia and fishes ; the muscar- dine of the silkworm, are all well proved to be communicable by the deposit of their spores, or some part of their substance, upon the external surfaces of the bodies of the animals on which they grow, or by their intro- duction into cavities opening on the exterior. Alltheinternal parasites, orEntozoa strictly * Ann. d. Sc. Nat. March, 1845, p. 182. t See Article SEMEN. J Consult, especially, on the whole of this subject, Dujardin's Hist. Nat. cles Infusoires, 1842. OVUM. 11 so called, are now known to be capable of true sexual generation, by means of ova, in their perfect or complete condition, and the whole class is remarkable for the great de- velopment of the sexual organs, and the pro- digious numbers of ova which they bring forth. But it has been ascertained that their ova are rarely developed into new being.s in the place of the abode of the adult entozoa : they are commonly subject, therefore, to migration from one organ to another in the same indi- vidual, or from one animal to another, or from the parasitic to the free-living condition ; and they have recently been discovered to present very remarkable changes of external form and internal organisation in their va- rious habitations ; so great, indeed, that many of them, previously believed to belong to species, and even to genera and families widely different, are now recognised as dif- ferent conditions of the same animal or species, and that many forms, whose mode of generation was unknown, are found to be derived by indirect production from ova, in a manner which will be more particularly de- scribed under the next section. Thus it appears that the only entozoa which are destitute of sexual organs, viz. those belonging to the division cystica, are very probably only imperfect forms of Taenia or other cestoids, which, so long as they are in the encysted or confined condition, do not reach their full development : but many of which, during their incomplete condition, are capable of being multiplied by a process analo- gous to gemmation. The greater number of the entozoa breed only when in the alimentary canal of animals, and the ova are excreted along with the foeces : it is obvious, therefore, that very many ova must be destroyed, and that a few only are liable to gain those peculiar situa- tions which are fitted to maintain them in their earlier conditions, or in their later stages, to bring them, as parasites, to their full state of development. The entozoa are usually found, therefore, in their most advanced stage, in the alimentary canal. There seems, on the whole, little dif- ficulty in accounting for the entrance of en- tozoa from without into the alimentary canal, or the pulmonary air-cells and other open cavities : and every new fact that has been observed relative to the occurrence of entozoa in man and animals, leads to the conclusion that the ova, or perhaps more frequently the earlier larval or undeveloped forms of the entozoa, gain access to these situations by introduction from without, and most fre- quently along with food and drink ; in those instances at least in which the entozoa migrate from one animal to another, or from an animal to the free state before returning to the parasitic condition. But the entozoa, which are, in general, in an incomplete state when situated in the close cavities or solid textures of the organs of animals, sometimes injiku their way from these situations into the alimentary canal, there to undergo their final development. Such appears to be the case with the Strongylus armatus, living in an incomplete state in aneurismal sacs of the blood-vessels of the horse, and in a fully developed state in the intestine ; the Stron- gylus vagans, in cysts of the porpoise, and afterwards free in the lungs ; the Ligula or Bothriocephalus solidus, in cysts of the ab- dominal cavity of fishes, and afterwards in their perfect state in the alimentary canal of sea-birds. The Trichina and Echinorrhynchi, imbedded in the muscular flesh in great quan- tities, are no doubt imperfect forms of other worms, which must migrate from these situa- tions to attain to their complete state. With regard to the manner in which the en- tozoa inhabiting the close cavities of the body, or imbedded in the solid substance of organs, either in the free or encysted condition, gain access to these situations, which has to many appeared inexplicable, excepting on the hypo- thesis of their arising actually in the places which they inhabit, observations are no less decided in proving them to be of external in- troduction. In the first place it may be stated that, al- though the ova of a considerable number of the entozoa are of so considerable a size as to render it improbable that they have passed as such through the capillary vessels, yet few, if any, of these larger kinds are observed en- cysted, and in others the ova are extremely minute, and might, without difficulty, be car- ried through most of the capillary vessels. In the next place it may be mentioned that the embryoes, or earlier forms of various parasites, and the ova of others, have been observed in considerable numbers in the cir- culating blood of various animals *, as showing that by this means the entozoa may be carried in their small and early condition into any part of the body of an animal which is fitted to afford the conditions favourable to their farther development. But in what manner have these bodies gained an entrance into the blood-vessels, or, in other instances, how may entozoa have penetrated into cavities or the parenchyma of organs, without being conveyed through the blood-vessels ? To this question, also, recent observations seem to furnish a satisfactory answer : for it has been ascertained that, in a number of instances, smaller or larger en- tozoa, but especially the former, pierce the tissues of animals with great apparent facility, being frequently provided in the young state with an apparatus of sharp hooks for that special purpose. Some of them have been observed in the act of passing through the * I may here refer to the original observations of Schmitz, (Berlin, 1826), and the more recent ones of Valentin Gruby, Gluge, Vogt, and others. See Valentin, Repertorium for 1842 and 1843. The Annual Report in Miiller's Archiv. for the same years, and in Wiegmann's Archiv. for Xaturgeseh. Valentin's account of the Ova of Distoma in the fluid covering the medulla oblongata of a foetal sheep (Miiller's Archiv. 1840, p. 317), and V. Siebold's Article 'Parasites' in R. Wagner's Handworterbuch, der Physiologic. 12 OVUM. solid substance of organs or through mem- branes ; and from the various stages of ad- vancement of others already referred to, seen in different parts of the same animal, little doubt can prevail that they must have done the same : but the aperture through which they make their way, besides being in most instances very minute, seems to close very rapidly and completely after them. So that the occurrence of entozoa in entirely isolated cavities — such as the aqueous cham- ber of the eye, or in the parenchyma of solid organs, — does not now present to our minds any valid objection to the view that in all in- stances they are introduced from without ; and it will be apparent, from the same con- siderations, that even the occurrence of en- tozoa in the foetus, of which there are un- doubted instances, and to which great import- ance has been attached as an argument in favour of their spontaneous origin, may be explained on the supposition of their ova, or young, passing from the maternal parent, through the blood-vessels of the umbilical cord, as is known to happen with various poisons. The whole history, then, of this remarkable class of animals, as it is now known, tends to support the general conclusion that they are all capable in their complete state of sexual reproduction, and that they gain the various sites of their parasitic habitations by intro- duction of their ova, or embryoes, or of more advanced stages of their growth from without, either directly into the open cavities, or more indirectly, by piercing the coats of vessels, membranes, *&c., into the close cavities and the parenchyma of solid organs.* A candid review of the whole evidence on this question leads to the inevitable conclusion, that, though all the difficulties or doubts which surround it are by no means completely removed, the hypothesis of primary or spontaneous generation receives little or no direct support from the accurate observation of the mode of origin of those animals which alone were supposed to afford proofs of such a kind of production; and that this view must, therefore, on the strongest grounds of analogy, be in the meantime aban- doned, for that which attributes the origin and reproduction of all organised beings to an undeviating connection through ova or germs, seeds or spores, between new individuals and others of identical species which have pre- viously existed. And if the present some- * As to the bearing of a knowledge of the habits &c. of the Entozoa upon the question of their spon- taneous origin, consult the able essay by Eschricht ; " Inquiries concerning the Origin of Intestinal Worms &c." in Edin. New Phil. Journ. vol. xxxi. p. 314. 1841, the article on Parasites by V. Siebold, in R. Wagner's Handwork der Physiol. ; E. Blanchard's Researches on the Structure &,c.f of Intestinal Worms, in Ann. d. Sc. Nat. 1848 and 1849, parti- cularly vol. vii. p. 121. Dujardin's systematic work, Hist. Nat. des Helminthes, 1845. And in connec- tion with this and the whole subject of spontaneous generation, the Systematic Treatises on Physiology of Uurdach, J. Miiller, Valentin, and Longet. what imperfect state of knowledge does not permit us to affirm this absolutely, as the result of direct observation, the exceptions are so few and unimportant, that they may be disregarded in the overwhelming evidence of a positive character in favour of the opinion, derived from analogy, that every organic being, if not produced in actual union with another, derives its origin from a germ or some such connecting part that has proceeded from a being of the same kind. If this be the present state of the argument in respect to the hypothesis of the first origin of organic beings, it need scarcely be added that the opinion which has attributed the pro- duction of various animals to conversion or gradual transmutation out of other species or genera, has still less of real to be adduced in its support. In the long series of ages in which authentic observations have been made on animals, no such examples have been ascertained, and there are no established facts which give any substantial grounds for believing that in the natural or wild state of animals there is any departure from that un- deviating succession of specific resemblance between parent and offspring, which seems to form one of the most constant of the laws of organic nature with which we are ac- quainted. 3rd. Production of dissimilar individuals among sexual animals by a non-sexual process : so-called Alternate Generations. From the foregoing general views it ap- pears that in all Vertebrated Animals, and in by far the greater number of Invertebrated animals, the process of permanent reproduc- tion consists in the development of the new being from the blastodermic mass formed by a peculiar process of cytogenesis in the fecundated ovum. But, as has already been shortly stated, there are some varieties among them in regard to the degree of directness with which the product of development from the ovum arrives at that state of maturity, or sexual completeness, in which it is capable of renewing the act of sexual generation. These varieties may be classed as follows: — 1st. The product of the ovum, being single, attains by a gradual process of development, when it leaves the ovum at birth, to nearly the same form and structure as its parents : this is generally called Embryological Development. 2nd. The product of the ovum, being single, is born or leaves the egg at an early period, and while comparatively imperfect, or, as it is called, in a larva state, and by one or more successive changes of development of a marked kind, afterwards reaches the specific or ty- pical form : these changes are usually called Metamorphoses. 3rd. The product of deve- lopment from the ovum does not itself become a complete animal, but gives rise, by a peculiar mode of generation of a non-sexual character, and therefore different from that by which fecundated ova are formed, to a new body, or to successive progenies of new bodies, one or more of which ultimately attains to the specific resemblance of the sexual parents by which OVUM. 13 the ova were produced. This is the " Alter- nating Generation" of Steenstrup, or what we might with Mr. Owen, in contrast to Me- tamorphosis, call a process of Metagenesis* ; and of which the single and multiple varieties might be distinguished according as the inter- mediate progeny consists of one or of suc- cessive new productions. In the two first and best known forms of sexual generation, the term Development has been usually given to a gradual process of changing and advancing growth by which the new animal is formed out of the ovum, till the period when it leaves it, or is said to be born ; and the term Metamorphosis has been generally applied to certain more marked and sudden changes of growth, apparently depending on the circumstance of the embryo or young animal having left the ovum, or having been born, at an early period in a com- paratively incomplete state of growth. But in establishing such a distinction between these terms, it is not meant to be affirmed that the changes which a young animal sub- ject to metamorphosis undergoes are indi- vidually or on the whole greater than those which occur in an animal which attains to its full growth by a process of development ; but merely that the one series of changes is less gradual than the other; and that the more marked changes which accompany metamor- phoses are related to certain conditions neces- sary to enable the animal which is born at an early period immediately to perform those acts which belong to its independent existence. It would indeed not be difficult to show that the changes which a mammal or a bird under- goes during its viviparous or oviparous de- velopment, are quite as remarkable and com- plete as those which occur in the change of a Batrachian reptile from its aquatic to that of its air-breathing condition, or of an insect from its larva to its complete form. In both of these instances one individual only is developed from the ovum, and that individual itself at last reaches sexual com- pleteness, and as being well understood they need not be longer dwelt upon here. But in the varieties of the reproductive process which are now to be more particularly noticed, the individual that proceeds directly from the ovum does not itself pass through the whole series of changes which are necessary to bring it to the form of the fully developed animal; but before it possesses any sexual organs, or has attained to sexual maturity, it produces from a minute germ formed in its body by a non-sexual process, a new indi- vidual, or a succession of individuals, the last of which only attains to the specific resem- blance of the parents, and acquiring sexual organs propagates the species by means of ova. This is the modification of the repro- ductive process already termed Metagenesis, and which has received so much attention under the name of ** Alternate Generations" since the publication of Steenstrup's cele- * Adopting a terra which has been used by Mr. Owen in his Lectures. Med. Times, vol. xx. 1849. brated treatise under the title of " Generations- Wechsel" in 1842* No examples of this peculiar modification of the reproductive process have been known to occur in the Vertebrata, and with one ex- ception they are confined to the lower and simpler of the classes of Invertebrated animals. They are not, however, entirely confined to the very lowest classes of these animals as dis- tinguished by the Zoologist, but rather to the simpler and less developed members of each of the several classes in which instances of them have been hitherto observed. The essential nature of this form of repro- duction consists, then, in the development from the ovum of an individual which is dis- similar from the parent or parents producing the ovum, and in the succeeding production from that individual, by a non-sexual process, of a progeny of one or more, or a succession of individuals, of which the last of the series resumes the parental form. While in animals, therefore, reproduced by the ordinary form of generation, the species is composed of entirely similar individuals, or of individuals differing only in sex ; in those animals which are sub- ject to the alternate or intermediate genera- tion, the species includes a variety of indi- viduals usually of dissimilar form ; of which some are without sex, and others are com- plete as regards the development of sexual organs. It has appeared to some authors that the phenomena in question are to be regarded as no more than peculiar modifications of the processes of development or metamorphosis, of such a nature that the product of the ovum becomes multiple instead of, as is more usual, remaining in its single individuality. But to admit the correctness of this view, it would be necessary to employ these terms in a sense widely different from that commonly given to them ; and, indeed, to modify the ideas of these processes of embryological development in a greater degree than seems warranted by what is at present known of their nature. The name of larva is usually given to the imperfectly developed animal that is born or leaves the egg at a comparatively early period, and fitted for independent existence in that state ; and in the changes of metamorphosis by which that larva attains to the complete specific form, great as these changes may in some instances be, we recognise that it is the individual produced from the ovum which itself undergoes these changes ; whereas in the various kinds of alternate generation, it is always by the formation of an entirely new individual, arising from a minute germ con- nected with the first, but to be distinguished from its parts, and without a sexual process, that the species is at last completed. The new individual may be single or there may be a multitude of them ; they may remain con- nected with the one producing them or they * A work which appeared originally in the Danish language, and in German in 1842, and of which an excellent translation into English has been pub- lished by the Ray Society in 1845. 1-A OVUM. may be detached and live independently, but they nevertheless constitute different animals, and cannot be regarded in any other light than as so many individuals distinct from the one producing them, although all are de- scended from one ovum, or all are necessary to make up the entire species. And it is further to be observed that each of these several animals may be subject to in- dividual metamorphosis, and that in some classes there is so gradual a transition from individual change to new production that it may be difficult to determine to which of these forms of reproductive development their phenomena ought to be referred. In that part of the article which treats specially of development our attention may again be called to some of the more remark- able examples of individual metamorphosis that are known : at present it is intended rather to bring prominently forward those instances of alternate generation which have been discovered since the publication of the Article GENERATION, or which, if previously known, may now be viewed in a different light, in consequence of being brought into comparison with other observations of a similar kind and of more recent discovery. We may first consider some examples of this process, or of one very analogous to it, in which the new animal is single. Echinodermata. — In several orders of this class a variety of the reproductive process has of late years been pointed out, in regard to which it may be doubted whether it is most of the nature of a metamorphosis or a meta- genesis, but which, as it has been considered by J. Miiller, the discoverer of the most in- teresting and remarkable of its phenomena, as in some measure analogous to the alternating generation, I will mention in this place ; the more so, that it might almost be looked upon as forming the connecting link between the direct and the alternating processes of repro- duction. In some of the Echinodermata it appears from the earlier observations of Sars that the young produced from the ova are developed directly into the parental form, passing how- ever through several marked modifications in the early stages of development. Thus, some of the star-fishes (Asteracanthion gtarialis, Sars) leave the egg as a ciliated free moving animalcule, then they become pediculated and attach themselves, have four club-shaped pro- cesses developed on them, and, lastly, they pass by the development of the rays and the internal organs into the complete form ; but here the whole, or nearly the whole, germinal mass of the ovum is converted into the embryo or larva, and the whole, or nearly the whole, of this undergoes the farther changes of con- version into the complete and sexual animal.* From the researches of J. Miiller it ap- * Sars, Fauna Littor. Norvegiae, 1846 ; and Ann. des Sciences Nat. ; Agassiz, Lectures on Comparative Embryology, New York, 1849 ; and a Letter from Desor to J. Mttller, in Archiv. fur Physiol. 1849, p. 79. pears that the mode of development now described is exceptional among the Echino- dermata, and that in other families of the erder Asteriadas, and in the Ophiura and Echinidoc, an embryo or larva of a peculiar kind, is formed by direct development from the fe- candated ovum, which is not itself converted into the complete animal, but rather serves as a temporary stock from which the perfect animal is subsequently formed in a manner that may be compared to gemmation. But it does not appear that more than one individual is developed from each primary larva stock, and this gradually dies away, so soon as its attached offspring has made some advance in its formation. This body, described under the name of Bipinnaria asterigera, as con- nected with an Asterias, is a comparatively large animal, with a long pediculated body, twelve or fourteen tentacles, an alimentary canal, consisting of mouth, gullet, stomach, in Fig. 7. Bipinnaria. asterigera (from Midler}. A, the young larva before the Echinoderm is formed. B, a more advanced larva, with the Asterias on its summit. c, the Asterias torn up to show its stomach, a continuation of the alimentary canal of the larva. OVUM. testine, and anus, and moves actively through the water. Sars who had observed this body in 1835, was the first to suggest in 1844^ that it might be the early condition of a star-fish*, and This view was confirmed by the admirable researches of J. Mullerf, and by observations of Koren and DanielsonJ, who have shown that the Asterias is gradually formed out of a small granular mass which surrounds the stomach of the Bipinnaria, and becomes se- parated from the stock when in a compara- tively early state of advancement. The larva stock moves about afterwards for a few days, Fig. 8. Pluteus paradoxus (.from Mutter}. A, Pluteus before the commencement of the formation of the Ophiura. B, Ophiura formed on the side of the gullet. * Wiegmann's Archiv. 1844, part i. p. 176. t Mem. of the Berlin Acad. 1846 and 1848. j Ann. des Sc. Nat. 1847, p. 348. and then appears to die without giving rise to any farther progeny. The gemmiparous larva of some other kinds of the Echinodermata was first described by J. Miiller as a distinct animal, under the name of Pluteus, before he was acquainted with the phenomena of its subsequent de- velopment: in 1846 he traced the relation between one kind of this body which he had called Pluteus paradoxus, and the Ophiura, and between another kind of Pluteus and Echinus, ascertaining it to be the same that has just been stated to exist between the Bipinnaria and the Asterias. The Pluteus presents the form of a quadrangular pyramidal frame, with four large ciliated limbs at the angles, and four smaller ones suspended from the middle below, while the upper part is surmounted by a sort of dome. It bears some resemblance to a Beroe, and might be de- scribed as the ciliograde larva of an Echino- derm. The form differs, however, somewhat for various species of Ophiura and Echinus. In the centre of the dome and round the mouth of the Pluteus a granular mass is de- scribed, and from the side of this, non-sym- metrically, the gemmation of the new indi- vidual proceeds. The Pluteus moves at first with great activity through the water, pro- pelled by its ciliated limbs and cirrhi; but as the new Ophiura or Echinus buds from it and spreads more and more over its dome, the Pluteus shrinks, becomes less active, and at last disappears.* Various other, forms of the Pluteus-like animal have been described by Miiller, and the process of gemmation has been traced by which the new Echinoderm takes its rise within them. The result of these discoveries is already to throw an entirely new light on the nature and organisation of this class of ani- mals ; but the species of all of those observed is not yet determined, and something still remains to be learned of the exact mode of origin of the new animal. By some-J* the process has been looked upon merely as a secondary development from the remains of the yolk attached to the parts first formed ; but the researches of Miiller do not appear to give support to such a view ; and would rather appear to show (as in Auricularia, fig. 9.), that the new animal is formed from a minute germ in a determinate part of the parent animal without that germ being traced to the yolk of the egg. In a farther series of researches on the larva? and metamorphoses of the Echino- dermata J, J. Miiller has pointed out that the Ho!othurida2 are formed from a larva body somewhat analogous to the Pluteus, but that, instead of a process of new formation, the whole of the larva is converted by a very remarkable metamorphosis into the Holo- thuria; and he has been enabled, from his * J. Mtiller, in Mem. of Berlin Acad. 1846 and 1848 ; Derbes, in Ann. des Sc. Nat. 1847. f As Carpenter, loc. cit. p. 939. j Memoirs of the Acad. of Scien. of Berlin, Nov. 1849, and April 1850, published in 1851, p. 35. OVUM. own researches and the comparison of some others, to bring the whole of the Echino- derinata under a general view, the result of which is the determination of the three fol- Fig. 9. Auricularia, or larva of Echinoderm (from Mutter). A, young larva of Auricularia. b, alimentary canal ; a, Echinoderm beginning to be formed. B, larger larva _of the same kind, a Echinoderm farther advanced. " lowing varieties of metamorphoses and pro- duction among them. In all of them the embryo, immediately developed from the ovum, has a bilateral symmetrical form, and passes by the subsequent metamorphosis into the radiated type. This change is, however, more or less direct, or by intermediate forms. 1. In the first variety the change of the bilateral larva, or embryo, into an Echino- derm takes place at its earliest period, when the embryo has a general covering of cilia, but not the special ciliated borders or limbs of the Pluteus. A part of the body of the embryo takes the form of the Echinoderm ; the rest of it is absorbed into the body of the new animal. This occurs in a part of the Asteriadae, as in Echinaster, Asteracan- thion, and others, described by Sars, Agassiz, Desor, and Miiller. 2. In the second variety the change occurs when the larva is fully organised, that is, when it possesses digestive organs and a spe- cial motor apparatus of ciliated borders or limbs. The Echinoderm is placed upon the Pluteus somewhat in the manner of a picture on an easel, or a piece of embroidery in its frame and stand, and incorporates a part of the digestive cavity with itself. The remains of the larva gradually disappear, as in Ophiura and Echinus ; or are broken off and die, as in Bipinnaria. 3. In the third variety the change of the larva takes place twice. First, it passes from the bilateral type with ciliated borders into the radiate type, and having taken some- thing of the shape of a barrel, it acquires a larval locomotive apparatus consisting of ci- liated hoops; and then from this state the Echinoderm is developed without any part of the larva being separated. Either the Echinoderm is formed of a part of the Vermi- form larva, and the rest of the larva is ab- sorbed into the Echinoderm, as in Tornaria ; or the whole larva is simultaneously trans- formed into the Echinoderm, as in Holothuria. From Busch's observations it appears that the Comatula passes very rapidly through the stage of the bilateral form into that which Miiller has called pupa with ciliated crowns. It is also an interesting fact in connection with the history of animal metamorphoses, that the early condition of the Comatula is that of a pedunculated Crinoid. Miiller has remarked that these pheno- mena partake in part of the nature of meta- morphosis, and in part of that of the non-sexual gemination of the alternate generations. As the Echinoderm arises like a bud in the larva, there is alternate generation ; but as the es- sential internal organs (that is, the alimentary canal from the stomach to the anus, but not the mouth and gullet) are taken into the new animal, there is also true metamorphosis. " I understand," says he, " by alternate ge- nerations nothing more than the succession of two forms of organism, of which the one arises in or upon the other as a minimum, or as a bud ; the second, that is, the deve- loped bud, is destined for sexual generation, producing from its ova the non-sexual larva, which again is destined for gemmation."* Adopting the view that the Echinodermata present an example of alternate generation, it is to be observed that the product is single in all the instances known : but in all the other forms of intermediate or alternate generation hereafter to be noticed, the product of non- sexnal gemmation is multiple. Polypina. — The animals usually compre- hended in the general denomination of Polypes or Polypina present very various kinds of structure and degrees of complication in their organisation ; and recent researches, as to their mode of development, which point out that some of them are subject to a process of alternate or dissimilar generation, would ap- pear to indicate a very different distribution * Loc. cit. p. 106. The researches of J. Miiller on this subject have been published in a separate form, as well as in the Mem. of the Berlin Acad. These Memoirs, and others on the same subject, will be found also in Miillers Archiv. 1846, p. 108; 1847, p. 160; 1848, p. 113; 1849, pp. 79. 84. 364. 400 ; and 1850, p 452. OVUM. 17 of these animals in the zoological system than that which has hitherto been followed. Most Naturalists are now disposed to separate from the true Polypina the Bryozoa, or so-called C'iliobrachiate Polypes, which, though pre- senting a considerable resemblance to the Polypes in their external anthoid appearance, yet approach much more nearly to the Tu- iiicated Acephalous Mollusca by their internal organisation; and remarkable affinities have been pointed out between some of the Poly- pina and Acalephce, which show that these classes, though very dissimilar in their external forms and mode of life, are in reality very closely allied in structure. The greater number of the Polypina are ag- gregate^or compound animals, that is, consist naturally of groups of individuals united or associated together on a common stem and branches, or on a more solid stock. But the common fresh water Polype, or Hydra, and the various Actinias of the sea coast, are, to a certain extent, exceptions to this general rule, and, as we shall see, differ also in regard to their mode of reproduction from most of the other families of this division of animals. The Actinia is usually a single animal : no doubt it is multiplied occasionally by buds, but these are thrown off and become developed usually in an isolated position. The Hydra sometimes occurs as a single animal, but more frequently during summer, and when well nourished, as a compound one ; the multiple individuals being developed by gemmation from the first or principal stock, and also themselves forming younger progenies by budding; but the indi- viduals so formed on the Hydra generally / Fig. 10. the hermaphrodite parent ; but in Hydra it would appear that it is principally in the au- tumn, on the approach of cold weather, that the sexual mode of propagation is substituted Fig. 11. Hydra viridis in different stages of extension and contraction, reproducing gemmiparously, attached to the roots of duck-weed. (From Eoesel.} separate from the parent stock when they have attained to maturity, migrate, and esta- blish themselves as independent animals, to form new buds. Both of these animals are capable of pro- pagation by ova formed in the sexual way : in Actinia this seems to be the more common mode of its multiplication, the ova being fecundated and developed within the body of Supp. Hydra viridis. A, Hydra of autumn, bearing an ovum, o,and two spermatic capsules, s, s. B, spermatic capsule burst artificially, showing spermatozoa. c (from Laurent), ova with young Hydra in various stages of development hanging out of them. D, D' (from Laurent), portions of the body of summer Hydra, with a bud sprouting. D, the ear- liest ; D', more advanced, showing the texture to be the same as the rest of the body. c 18 OVUM. for that of gemmation which takes place throughout the whole of the summer.* The ova of Hydra are simple vesicular cap- sules of a brownish colour formed in the sub- stance of the wall of the animal's body, and separated from it previous to the development of the young ; while the spermatic filaments are formed in smaller conical capsules placed nearer to the base of the tentacula either in the same or in different individuals.-}- The for- mation of the young Polype has been observed by Laurent j to take place directly from the internal substance of the ovum, in which, how- ever, he has not traced in a sufficiently complete manner the individual steps of the changes of development (see fig. 1 1 . c.). The origin of the ovum in this animal is shown to be quite dif- ferent from that of a bud : the former having the shape of a distinct vesicle from an early period, the latter not being perceptibly more than an extension of some part of the sub- stance of the wall of the body, and precisely of the same colour and structure (see fg. 11. D,D'.). The Hydra, therefore, while propagating very frequently by gemmation, is capable of reproduction also by fecundated ova, which are directly developed into the parental form. But many of the true Compound Polypes pre- sent examples, in their multiplication by gem- mation, of the production of intermediate forms of animals between the ova and the perfect sexual individual, — a mode of repro- duction, therefore, which may be referred to Steenstrup's general law of Alternate Gene- rations. Thus, to begin with the simplest form of these animals bearing the nearest resemblance to the Hydra, in the Coryne and Syncoryne, at certain seasons of the year, multiplication takes place from the stem or root by gemma- tion, the buds being developed in the form of attached Polypes ; but at other times there are developed from the buds, without the con- currence of sexual organs, a set of delicate Medusa-like animals, similar to the Oceania, or those of the naked-eyed kind : these soon be- come detached, swim about freely in the water, acquire some of them male and others female sexual organs, and produce fecundated ova. * This effect of the cold season in changing the mode of production from gemmation to oviparous formation, thus checking growth, but providing for the preservation of the species through the winter, is, as remarked by Dr. Carpenter, an interesting ana- logy with the change that is known to occur in the mode of production of the Aphis insect ; see Prin- ciples of Physiology. -j- The co-existence of ovigerous and spermigerous capsules on the body of the Hydra has been observed by many, as, first by B. de Jussieu, in 1743 ; (Ab- hand. der Swed. Acad. 1746, vol. viii. p. 211): by Trembley, in 1744 (Mem. sur les Potypes d'Eau douce) ; by Rb'sel (Insecten-Belustigung) j Pallas, in 1776 (Karakteristik der Thier-pflanzen, p. 53) ; and more recently by Ehrenberg, in 1836 and 1838 (Verhand. der Naturforsch. FreundeJ in Berlin, 1838, p. 14) ; V.Siebold (Lehrbuch derVergleich. Anat.) ; and by myself (Edin. New Phil. Journ. 1847). J Nouv. Rech. sur les Hydros d'Eau douce, 1814, Voyage de la Bonite. These ova give rise, by their development, to a ciliated moving embryo : this soon becomes fixed to a spot, and is gradually converted into a Polype, similar to that from which the Medusa-like animals were formed.* Fig. 12. Syncoryne, developing a 3Iedusoid progeny. Oceania (From Desor.') A, natural size. B, a portion enlarged, showing the budding of Medusoids in different stages. c, one of the Medusoids, naturally detached. D, another, farther advanced ; o t, ovary, or tes- ticle, placed on the alimentary canal ; o', ova. R. Wagner appears to have been the first to observe Medusoid bodies produced from the Polype animals, as in Coryne aculeata, in 1833f , but the more full observation of the remarkable phenomenon of their formation is due to the researches of Sars, Lowen, Steen- strup, and VanBeneden, who have ascertained the relations of the Polype larva and Medusoid progeny, and the production of ova from the latter. DujardinJ has also carefully traced the production of the free Medusoid bodies from a Syncoryne, which he has called Stauridia, and has farther ascertained the sexual condition of these Medusoids, observed the formation of their ova, and the subsequent development of these ova into Polypes. * See fig. of Syncoryna Sarsii, from Sars, Fauna Litt. Norveg. 1846; and Steenstrup's figures of Coryne fritillaria, tab. 1. figs. 41. 43, and Desor, in Ann. des Sc. Nat. 1840, pi. 2. figs. 13. to 16. f Isis for 1833, p. 256. Also in Coryne vulgaris, in Icones Zootom. Tab. xxi. 1841. I Annal. des Sc. Nat. 1845. OVUM. 19 In a certain number of the Campanulariae, Sertulariae, and Tubulariae, of which the in- ternal structure is more complex than in the Coryne, and in which the Polype always na- turally presents a branched form, or groups of distinct Polype heads formed upon a common stem by gemmation, it is now well ascertained that the Polype state is not the only nor the complete condition of the animal, but that by Fig. 13. Branch of Sertidaria geniculata, magnified, shewing polypes, and ovigerous capsules. a process, in some instances similar to that above described, in others, somewhat different from it, a set of bodies, charged with the office of the sexual production of the ova, are deve- loped in place of the more ordinary Polype heads or individuals. In the Campanularia ge- latinosa, according to Van Beneden, the gene- rative heads are close bell-shaped capsules, within which small Medusoid bodies are deve- loped by a process apparently analogous to gemmation, or, at all events, without sexual .generation, and each of these Medusoids be- coming free, move about in the adjacent fluid as independent animals. The farther destina- tion or changes of these Medusoid bodies have not yet been observed, but from parallel observations in other similar animals, it is believed that they afterwards attain to sexual completeness, and form ova which are de- veloped into the Polype form.* * See the View of Campanularia geniculata, by Van Beneden, in Mem. de 1'Acad. de Bruxelles, 1844, vol. xvii. ; and Ann. des Sc. Nat. torn. xx. p. 350, 1843. See also the very interesting account of Tu- But the interesting observations of Loven*, and also some previous observations of Lis- ter y, would show that in the Campanularia Fig. 14. Campanularia. ( From Desor.) A, po rtion of a branched stem, magnified, c, non- sexual head or individual ; gg, two capsules, or modified heads, producing Medusoids by gemma- tion, in different stages ; m, Medusoid escaping ; m' m", Medusoids more advanced, moving freely by the contractions of their disc. geniculata, and in Tubularia, the Medusa-like bodies may in some instances not be detached from the Polype heads or capsules, and may even not be developed fully into the Medusa form, but nevertheless produce their ova in that attached situation, and thus give rise to ciliated embryoes, which, when excluded, move for a time, and then, like the others arising from the detached Medusa?, become converted into Polypes. According to Desor, of Boston J, the same Campanularia may at one time produce two kinds of capsules, the one set containing ova the other spermatozoa ; the Medusoid progeny not being developed, and the ova giving rise to forms similar to the parent Polype : and M- S. Schultze, of Greifswald, has confirmed this statement§, apparently without the know- bularia, in Dalyell's Remarkable Animals of Scot- land. * In Wiegmann's Archiv, 1837. f Phil. Trans. 1834. t Ann. des Sc. Nat. 1849, xii. p. 208. § Muller's Archiv, 1850, p. 53. c 2 20 OVUM. Fig. 15, •^V^PP* Campanularia geniculata (A and B from Loven, as copied by Steenstrup). A, modified or bell-shaped polype head or cap- stile, producing the female individuals at g,g>g'} the earliest of these budding from the granular stem gf. B, the female heads expanded from the bell : one of them containing two ova, oo; the other con- taining two ciliated embryoes, of which one is issu- ing at the summit of the attached medusoid, e e. c (from Schultze), male heads of the same spe- cies of Campanularia ; p, upper part of the polype head, or bell-shaped capsule ; c, sexual capsule, or modified attached Medusoid, containing spermato- zoa ; , a pile of medusa discs separating, and new tentacula formed on the polype at the base ; r, the same, with more of the discs separated; the strobila returning to its polype state and budding at the side. Development of Medusae. ( From Sars, Steenstrup, and Dalyell.} a, b, ciliated free moving embryo from the ovum ; c, embryo attached by its pedicle ; d, its tentacula beginning to be formed ; e, with four, /, with eight tentacula ; g, the fully developed polype, producing other polypes by gemmation ; h, i, k, transverse di- vision and development of Medusae from the polype stock or strobila ; /, a pile consisting of four Me- dusoids just about to separate ; m, n, and lower be capable of multiplying itself, or producing other similar attached Polypes by gemmation from its side or base, or from a running stolon below it. The subsequent change of each of these polypoids is remarkable. It has been described by Sars and Dalyell as follows : — The body undergoing some elongation be- comes partially divided by transverse grooves, into a range or column of imperfect Medusae, attached still to each other by their adjacent surfaces, but presenting at their borders, in various degrees of advancement, the division into rays or lobes which belong to the Me- dusa; the upper or terminal one having deve- loped upon it a set of radiated processes dis- tinct from the tentacles of the Polype and much longer than those of the rest. These young Medusae are successively separated from the stock by the deepening of the transverse clefts between them. They then move about as independent animals, and proceed in their farther growth and development to sexual and other completeness. These bodies, therefore, are subject to two kinds of multiplication, which are very different : by simple gemma- tion a number or a colony of Strobilae may be produced, and by transverse fission and deve- lopment a number of Medusae may be thrown off from each Strobila. A considerable number of the Medusa pro- geny having been separated, the Strobila stock generally returns to its polypoid condition, Fig. 17. Production of Medusas (Aurelia aurita) from Po- lype stock. (From Desor.) A, Medusa-form larvae on the stock above the polype, which remains at the base, a. B, lower surface of a detached Medusa. c, D, natural size. Young Medusas forming from the polype above its disc. c 3 22 OVUM. and may remain for a long time in that state ; continuing to multiply by budding into others of the same kind, and occasionally giving rise by the process of fission to its Medusa progeny. The observations of J. Reid * have shown that the Polype or polypoid stock may remain for a very long time in this condition without forming any Medusa progeny; and these obser- vations, as well as those of Steenstrup and of Desor, appear to show that these Polypes bear a considerable resemblance in their internal structure to the Medusae which they produce by gemmation. The latter author, indeed, is inclined to believe that the new Medusa ani- mals are produced not by a mere transverse fission of the Polype, but by successive gem- mation on its summit, that is, round its mouth and within the tentacula; and he states that he has observed the Polype remaining with its tentacles at the base of the Strobila of Medusae. The observations of Dalzell and Fig. 18. Medusa larva. (From J. Reid.} A, Polype before it has undergone any gemma- tion of Medusae, showing the mouth and four canal openings. B, the strobila or larva forming Medusae. c, lower surface of one of the young Medusa?, after separation. J. Reid appear, however, inconsistent with this view ; but it is possible that there may be varieties in respect to the mode of formation of the Medusa progeny, so that in one set the tentacles of the Polype may be included in the upper Medusa, and when all the progeny is separated, new tentacles may be formed on the Polype stock at the base, while in others the budding Medusa may be within the circle of the tentacula of the Polype. It appears from recent investigations that * Ann. and Mag. of Nat. Hist. 1848. others of the Acalephae also undergo remark- able processes of non-sexual multiplication. According to Huxley's recent most interesting researches*, the Physsophoridae, Diphydae, and Physalia, are to be regarded as compound organisms in which the floating processes of most various form are analogous to Polype or attached Medusa individuals, which are the bearers of sexual organs, in some of one kind, in others of both, and others of which are neuter, on the same compound stock.f These are probably a progeny developed by budding from a single individual, which is the parent stem. By these discoveries a remarkable relation is shown to exist between the medusoid and polypoid animals. Some we have been ac- customed to see principally in their largest and most developed condition as Medusae, others are best known in that polypoid condi- tion in which they remain for the longest time ; but we must regard that condition in which sexual reproduction takes place as the complete one, and this we have seen is in both the Acaleph or Medusa form, while the Polype or polypoid state, however permanent it may appear, is to be looked upon as a pre- paratory stage, in which, it is true, multiplica- tion of its own kind may occur by gemmation, but which can only effect the true reproduc- tion of the species by forming its progene of Medusans to which is committed the offic of producing the fecundated ova. This, there- fore, is another example of multiple metage- nesis, or alternating generation, j Mollusca. — Among the Mollusca the only examples of alternate generation that are yet known have been observed in the Tunicated Acephala : and among these, three modifica- tions of the reproductive process are known in the Bryozoa, Ascidia, and Salpidae. The Bryozoa, or so-called Ciliobrachiate Polypes, long ranked with the Polypes on account of their union in branched groups, their radiated arms, and retractile body, but now regarded as more nearly allied by their internal organisation to the Tunicated Mol- lusca, present a very marked example of the multiplication by budding of the progeny of a single ovum. These animals never continue for any considerable time as single or distinct individuals, but, multiplying by gemmation, form numerous colonies, in which the new individuals remain connected with the pri- mitive one from which they have proceeded and with each other. They thus always con- stitute compound groups spreading from the first individual as from a centre. All the in- dividuals of the group may acquire sexual completeness, and the male and female organs are united in each individual : the ova are fecundated within the cavity of the mantle; * Phil. Trans. 1849, Pt. ii. f Professor Goodsir has informed me that his ob- servations on Stephanomaia are quite confirmatory of this view. | See also on this subject the interesting treatise by Prof. E. Forbes, on the Naked-eyed Medusas, in Ray Soc. Pub. 1848. OVUM. 23 on leaving the parent body they become deve- loped into a ciliated embryo, which, for a time, moves freely about, then becomes fixed, un. dergoes farther changes in being developed, Fig. 19. A series illustrating the development by ova of Pedi- cellaria. (After Van Beneden.) and now from its own body in some, and in others only from the spreading part of the stem or base which supports it, proceeds the gemmation of other individuals of the colony, all of which apparently are capable of sexual generation when they arrive at maturity.;}: The Ascidian Tunicata present another mo- dification of the reproductive process now under consideration. Two forms of these animals exist, both perfect, viz. the simple and the compound; but these are not related to each other in the same manner as the two kinds of Salpians; for each kind is capable of propagating its like by generation. The soli- tary ones rarely multiply by gemmation, and when the}' do so the individuals separate from the stock; but the compound animals always undergo this mode of multiplication, and the multitude of individual Ascidians are in this form collected together in a mass of various shape, in which the circulation of fluids is for a time common among the different indivi- duals. The individual animals produced from the stock by gemmation attain to sexual com- pleteness, and propagate by means of ova, in the same manner as the solitary or distinct Ascidiae do. The young of these animals undergo a re- markable metamorphosis : they are first ex- cluded from the egg in the form of a moving tailed body, somewhat like a minute tadpole^; and this caudal organ of motion is lost pre- vious to their becoming fixed, and the deve- lopment of the more complex organisation.f Although the changes to which both the Bryozoa and Ascidian Tunicata are subject in * Van Beneden, in Mem. de Bruxelles, torn, xviii. See the Article Polypifera, for an account of these researches. t See Mr. Rupert Jones's excellent Article TUNI- CATA for an account of these phenomena, and the special Memoirs of Milne-Edwards, sur les Ascidies Composees, &c., Paris, 1832; Lchvig and Kolliker, in Ann. des Sc. Nat, April, 1846; Van Beneden, sur les Ascidies Simples, Brussels, 1847. their early state present some very striking phenomena of metamorphosis, yet there is nothing in either which fully deserves the name of alternate generation, for all the individuals of which these compound animal structures consist are alike sexually perfect, and there does not appear to subsist any necessary con- nection between the nonsexual process of multiplication, and the subsequent exercise of the sexual function. There are, in fact, scarcely any intermediate stages of non-sexual exist- ence such as are described in the true in- stances of alternate generation. It is deserving of notice, however, that Lowig and Kolliker are of opinion that in some of the Botryllidae numerous embryoes are at once developed from a single ovum by its division, these indi- viduals subsequently multiplying by gemma- tion into the perfect sexual animals. Fig. 20, Bowerbankia densa. (After Jarre.) a, one of the animals fully expanded. b, a similar animal completely retracted. c, an immature animal. d, one of the gemma? in its earliest state. SalpidfB. — The most marked example of alternating generation among the Tunicata is that which, since its first discovery by Chamisso, in 18 19, has been known to occur in the Salpidae. This process has been so well and fully described in the article TUNICATA, that it is not necessary to give more than a short outline of it in this place. These animals are known in two states, viz. solitary and ag- c 4, OVUM. gregated ; the latter being not organically united like the compound polypes, but merely adher- ing more or less strongly to one another so as to form a chain. The aggregated, but not the solitary kind, possess sexual organs; and it would appear, though this is not yet deter- mined with certainty, that all the individuals of one chain are of a similar sex either male or female. Fig. 21. Solitary and aggregated Salpce. (From Sars.) A, solitary Salpa, with chain of aggregated ones, g, budding from it. B, this chain magnified, shewing the successive sets in different stages. c, one of the more advanced aggregated Salpae from a chain,/, the place of a foetus formed by sex- ual generation. D, foetus from another more advanced, magni- fied ; A, the yolk, by which it adhered to the pa- rent ; g, the place of the germ for the aggregated chain. All the individuals of a chain of aggregated Salpae are produced from a solitary one by a process of internal gemmation, or gradual deve- lopment from an internal stolon, or gdrm-stock, from which they are detached gradually and in successive groups : all the individuals of the chain are contained within a tube, and become united to each other after their development, presenting a series of groups of different de- grees of advancement ; but the individuals in each group being nearly at the same stage of development. The distinct or single Salpae, which, with the exception of the want of the sexual organs, do not differ materially from the in- dividuals of the aggregated chain, are produced from fecundated ova which are developed within the body of the parent. These ova differ from the germs from which the aggregated in- dividuals take their origin in the possession of a yolk, and external envelope. Their de- velopment proceeds to its termination within the parent body, and the young Salpa is already provided with the internal stolon for the gem- mation of its chain progeny, before it passes into its separate state ot existence. The solitary Salpae may be looked upon, therefore, probably as incomplete or larva forms, and the aggregated are the fully deve- loped sexual individuals. The generation of this animal, therefore, is precisely an example of that succession of two different kinds of individuals which has been distinguished as alternation of generations ; each fecundated ovum of the sexual individuals being developed into an animal which never acquires sexual organs, and which produces by a process ap- parently of the nature of gemmation, a nu- merous brood of individuals associated in a chain ; all of which are sexually perfect, one set developing only spermatozoa, and the females among them being the producers of the ova, which are the source of the new generation.* Although no other instances of alternate generation have yet been observed in the class of Mollusca, yet it is possible that modi- fications of this process may hereafter be dis- covered. An observation related by Agassiz f, in regard to the development of the ovum in one of the Eolidae, deserves to be recorded, as it may be found to constitute an approach to the metagenetic process. After having de- scribed the usual process of division of the yolk in which the first stages of development consist, and the farther progress of formation in the Eolis, he says, — " But the most curious phenomenon which takes place is this ; that the whole yolk does not constantly go to form one single individual. But there may be instances when the mass of yolk, which has been subdivided into cells, is itself di- vided into two or three or more masses, which grow independently, several individual animals arising from one mass of yolk, which thus divides." Entozoa. — Among the Entozoa the process of reproduction is effected by very various means. All the Nematoidea, or round worms, are of distinct sexes ; and their fecundated ova are developed into the parental form without any metamorphosis of a marked kind, (ex- cepting perhaps in the Echinorrhynchi, the * See Savigny, Me'm. sur les Anim. sans Vertcb. 1816 ; Chamisso, De Salpis, 1819 ; Meyen, Ueber die Salpen ; Eschricht, in the Isis, 1842 ; Sars, Fauna Littor. Norvegiae, 1846 ; Krohn, Ann. des Scien. Nat. July, 1846 ; who first pointed out the existence of spermatozoa in certain individuals of the aggre- gated chain. t Lect. on Comparative Embryology, Boston, 1849, p. 81. OVUM. 25 process of generation in which is not fully understood,) nor any intermediate process of gemmation. A few of them, however, ap- pear to become encysted in the parenchyma of organs in their young or undeveloped condition, and some in a form different from the parent, as in the Trichina of the muscles, the so called Filaria of the peritoneal cavity of fishes, and the Vibrio tritici. These en- cysted Nematoidea have not been observed to be possessed of sexual organs*, and they are not known to be multiplied by gemma- tion ; it is probable, therefore that, to attain the place of their full development, they must be subject to migrations from one animal to another, either directly or in other ways, as through water and vegetables. The ova of these animals appear to possess a remarkable tenacity of lite, as exhibited by their long and obstinate resistance to the noxious effects of external agents, -f- The Cystic, Cestoid, and Trematode orders of the Entozoa present a more varied process of ceneration, the investigation of which has of late years attracted considerable attention, and which has led to most interesting results as to the nature and relations of several forms of these animals, which were previously re- garded as of a most anomalous kind. The Cestoid and Trematode Entozoa have long been known to possess the sexual organs in the hermaphrodite arrangement, and to pro- duce fecundated ova ; while the Cystic En- tozoa have been observed to multiply only without sexual organs, and by a process analogous to gemmation, and their first origin has been till lately involved in the deepest obscurity. We shall presently see that many, if not the whole of them, may be either un- developed or metamorphosed aberrant forms of cestoid or trematode animals. J This view appears first to have been sug- gested by Steenstrup, in connection with his researches on alternate generations § ; and it * See a Memoir by V. Siebold, on the Nonsexual Nematoidea, in Wiegmann's Archiv, 1838. t Dr. Henry Nelson and I have observed the de- velopment of the ova in Ascaris mystax to proceed for several days, while the parent bodies containing them were immersed in oil of turpentine. J For a notice of the generation of the minute parasitic animalcule called Gregarina, see the^ pre- vious account of the reproduction of Infusoria,^ § See Ray Society's Translation, 1845, p. 100. " It is not unlikely," says Steenstrup, " that in course of time, it may happen with them (Cystic Entozoa), as it has with the whole division of the asexual Trematoda of Siebold, viz. Cercaria, &c., that they must be rejected from the system as being earlier forms of development, or earlier generations of other animals." V. Siebold remarks in a note at p. 157, of his Lehrbuch der Vergleich. Anat. part i. published in 1845, " Here the doubt arises whether the asexual Cystica really deserve to be considered as independent animals. It is very probable that the vesicular worms are undeveloped Cestoids," &c. See also note at p. 111. Von Siebold has developed these views more fully in a recent Mem. in the Zeitsch. fur Wissensch. Zool. July, 1850, translated in the Ann. des Scien. Nat. vol. xv. 1851, p. 1/7; and in the article Parasites, in Wagner's Handwor- terbuch der Physiologic. E. Blanchard in his Keen. has since been adopted, in somewhat dif- ferent forms, by V. Siebold, Blanchard, Du- jardin, and Van Beneden, and rendered extremely probable by the researches of these and some other observers. Previous to the adoption of this view, helminthologists, looking upon the Cystic Entozoa as dis- tinct and independent animals, were at a loss whether to regard them as ascertained excep- tions to the sexual mode of propagation, or to continue to prosecute their inquiries in the hope of being able to discover a process of generation in them analogous to that prevail- ing in the greater majority of the animal kingdom ; and many were thus misled into the error of searching for ova where none existed or were required. Thus Gulliver erroneously de- scribed certain calcareous particles in the mem- brane of Cysticercus as the ova of the animal*, and H. D. Goodsir, in his instructive paper on the production of the young in that animal, and in the other forms of Cystic Entozoa f, failed to distinguish between that which might be merely a process of gemmation and the origin of the embryoes from true ova.J Cystic Entozoa. — The Cystic Entozoa pre- sent themselves in three principal forms, viz. Acephalocyst, Caenurus, and Cysticercus. The two first are usually found as compound or aggregated animals; the last is more fre- quently seen in the single or isolated condition. Some of the vesicular hydatid tumours, constituting the various kinds of so called acephalocysts, have long been known to con- tain small Echinococci floating in the fluid of their interior. Repeated observations have demonstrated the existence of these animals in the acephalocysts ; and it seems very pro- bable that, in the end, it will be necessary to withdraw the distinctions between the various kinds of these cysts, as they will all, by suffi- ciently accurate observation, be found, at some period of their growth, to contain in a more or less complete condition, the small animals of Echinococci, or their remains. § The Echinococci are produced by non- sexual generation, or by gemmation from the membrane of the vesicle, probably from the middle or germinal membrane, as it has been sur 1'Organis. des Vers, in Ann. des Scien. Nat. 1847 vol. vii. p. 120. excludes entirely the Cystica from a separate place in the systematic arrangement, bring- ing them under Cestbidea, and affirms decidedly that the distinction between them ought now to cease, as they are shown to be different states of the same animals. He refers to De Blainville as having previously entertained the same view. See also Dujardin, in Annal. des Scien. Nat. for 1813, and Hist. Nat. des Helminthes, 1845; Miescher, Be- richt iib. die Vcrhand. der Naturforsch. Gesellsch. in Basel, 1840; and Van Beneden, Ann. des Scien. Nat. 1851, p. 309 ; and a work on the Entozoa, pub- lished at Brussels, in 1850, which I have not seen. * Med. Chir. Trans, of Lond. vol. xxiv. 1841. f Trans. Roy. Soc. Edin. vol. xv. 1844, and in Anat. and Path. Observations, 1845. j See also Rose, in Med. Chir. Trans, vol. xxxi. 1848. 8 See V. Siebold's Report on Zoology, in Ray Society's publications, for 1845 and 1847 ; also Bur- dach's Physiol. B. ii. 26 OVUM. called by H. D. Goodsir ; and they have been cells, from which it is supposed other young observed, in some instances, attached in pedi- animals or heads may be formed.* culated vesicles, singly or in groups, to the inner Fig. 23. Fig. 22. Echinococcus hominis. (From Wilson.') A and B, grouped and single Echinococci, at- tached by peduncles to the inner membrane of the cyst, c, a contracted, and D, an expanded Echino- coccus; a, the peduncle. E, a more advanced animal, shrivelled. surface of the cyst.* While enclosed in the pediculated vesicles, the head of each echino- coccus is retracted within the short vesicular body in a manner which seems to be general among the young of encysted Entozoa. They are aftersvards set free, and in this state are found floating as minute whitish particles in the fluid of the cyst. They then present the appear- ance of minute heads of Taeniae, with a short body scarcely larger than the head ; the latter part being furnished with a terminal double circle of booklets, and four suckers.f The mode of gemmation may probably vary in different circumstances, more particularly in regard to the extent to which the progeny of gemmation may or may not repeat the for- mation of others of the same kind ; but every thing that is known of the acephalocvstic productions seems to point to the view that they are all nearly allied, and that they are abnormal or aberrant conditions of Taenia- larvae, which, when they become encysted, are incapable of development into the cestoid form which belongs to those that have reached the free intestinal habitation. The Casnurus, which has been met with principally in the brain and some other parts of the sheep and some other Ruminating ani- mals, consists of a large cyst or vesicle with a number of small heads projecting on its ex- ternal surface: each head resembles closely that of an echinococcus animalcule, presenting the same circle of booklets and four suckers. According to H. D. Goodsir, they are at- tached to the middle membrane of the cyst, from which they sprout at first, carrying the outer one along with them : the neck contains * E. Wilson's paper in Med. Chir. Trans, xxviii. 1845 ; and H. D. Goodsir, Anat, and Path. Obs. f See Curling, in Med. Chir. Trans, vol. xxiii. ; and Mttller, in Jahrsbericht of Archiv, 1836. p. 10G. Caenurus cerebralls, magnified. (After Bremser.} ««, part of the general vesicle; b, an expanded head ; c, a shorter head, showing the double circle of booklets. The Cysticercus has been described in two forms ; 1st, in its simply vesicular state, and 2nd, in its fasciolated condition, or in its transition, as it may beheld, to the cestoid, or tape form. The vesicular Cysticercus has Fig. 24. Cysticerci. A, Cysticercus longicollis (from Bremser), en- larged. B, Cysticercus from the human eye (ex- tracted by Dr. Mackenzie), magnified five dia- meters. only one head ; but the structure of that part is precisely the same as in the Caenurus and Echinococcus, and, we may add, not far different from that of the Taenia itself. They are usually developed singly, that is each vesicle with one head : but some ob- servers f allege that they have seen internal vesicles near the neck, which they look upon as young, or as a progeny of gemmation in that situation. The Cysticercus fasciolaris, as it has been observed in the rat and mouse, presents the remarkable fact of a Tsenia in various states of development, from the vesicular condition of * H. D. Goodsir, loc. cit. f As Rose and II. D. Goodsir, loc. cit. OVUM. 27 the true Cysticercus, to a form in which the caudal vesicle has diminished to such an extent as almost to have disappeared, while at the same time the body has been divided into segments by transverse grooves, as in the Taenia ; and in some instances these seg- ments have even acquired sexual organs while the animal was still encysted, a circumstance which has never been observed in any true Cysticercus. Fig. 25. Cysticercus fasciolaris of the Mouse, and Tcenia crassicollis of the Cat. A, Cysticercus fasciolaris from the liver of the mouse, natural size. B, the head of the same, magnified. (From Dujardin.) c, head and first segments of the body of Taenia crassicollis of the cat, showing the double circle of hooks ; a few of the smaller under circle being seen where one or two of the larger ones have fallen off. A close comparison of the structure of the Cysticercus fasciolaris of the rat and mouse in its various stages of development with the Taenia crassicollis of the domestic cat, has shown an almost complete similarity between these animals, and has suggested the view that the encysted Taenia (which the Cysti- cercus fasciolaris in truth is) may attain its full development as a Taenia in the intestinal canal of those animals which prey upon the smaller Rodentia, in whose liver it begins to be developed in its first simple vesicular form, and gives the greatest probability to the sup- position that there may be a similar general relation between the Cystic and Cestoid En- tozoa, not of the same animals, but between the tapeworms of different tribes of predaceous animals and the vesicular worms of others serving them as food.* * Dujardin, Hist. Xat. des Helminthes, 1845. E. Blanchard (who does not appear to have fully appre- ciated the necessity of change of habitation for the entire development of the taenia), Sur 1'Organisation des Vers, Ann. des Scien. Nat. J848, torn. x. p. 348. V. Siebold, in Zcitsch. f. Wiss. Zool. 1850, and Ann. -••iences Xat. 1851. I am indebted to Dr. Henry- Nelson, for an account of some interesting researches on this subject which formed a part of his Inaugural Dissertation "On the Development of the Entozoa," on obtaining the degree of M. D. at the University of Edinburgh, in 1850. The limits of this article The different phases of development, there- fore, in which the so-called Cysticercus fascio- laris has been seen in the same and in dif- ferent animals which they inhabit, leave little doubt that they are encysted Taeniae, which proceed to a much more advanced stage of development than is usual with the vesicular and encysted form of these Entozoa ; and we are warranted, from the great similarity of structure, in adopting the view that the true vesicular Cysticerci, the Casnuri and Echino- cocci, are morbid or metamorphosed and aberrant conditions of the embryoes of various Taeniae, which may be capable, to a greater or less degree, in different kinds of animals, of multiplying their own incomplete forms by a process of non-sexual gemmation, but which never, in the encysted condition (except in the instances already referred to of the fascio- lated kind), attain to sexual completeness ; but which either undergo a retrograde change, and thus form tumours and various pathological deposits in the seat of their cysts, or become developed to such an extent as to be injurious or destructive to the animal in which they reside.* Free Tapeworms. — Three principal forms of cestoid worms are now distinguished from one another, viz. Taeniae, Bothriocephali, and Tetrarhynchi ; the two first have long been known and sufficiently well characterised in their fully grown condition, though little under- stood in their early or incomplete states ; the history of the third, until recently, has been involved in great obscurity, as it has been most variously described by different ob- servers both in the earlier and more advanced stages of its growth. It appears now to be ascertained that all of these cestoids are com- plete animals, with a single head, a body composed of a multitude of segments, each of which contains male and female sexual organs, which are developed only when the entozoon is living free in the alimentary canal of animals belonging principally to the Verte- brata. The Taeniae inhabit chiefly the alimen- tary canal of mammals and birds ; the Bothrio- cephali and Tetrarhynchi more frequently that of fishes and reptiles, and the latter a few mollusca. The Tetrarhynchi have been more frequently described in the encysted and im- perfect condition than in the full-grown form, and in such varieties, that V. Siebold has mentioned about sixty different kinds of worms described by various authors under distinct ap- pellations, which might, according to him, be prevent me from entering into the details of Dr. Nelson's observations, which have not yet been pub- lished. It is enough to mention that a very careful comparison of the Cysticercus fasciolaris of the mouse and rat, in various stages of its development, with the Taenia crassicollis of the cat, enabled him to confirm, in a most satisfactory manner, the view which, unknown to Dr. Nelson, had previously been taken by V. Siebold, that these cystic and cestoid forms are different stages of one and the same animal. See also Leuckart on Cysticerci, in Wieg- mann's and Erichson's Archiv for 1848. * See Gulliver, in Med. Chir. Trans. 1841. 28 OVUM. brought under the genus Tetrarhynchus. In fact, this kind of animal undergoes such re- markable changes in its transition from its first simple Echinococcus-like encysted form to its free segmented sexual Taenia-like shape, that it is not wonderful that its history should have been obscure, and that great doubts should still prevail with someHelminthologists as to its origin, development, and zoological relations.* It has already been observed, that none of these three kinds of Cestoid Entozoa attain to sexual completeness while they are en- cysted ; and it seems probable that they are all subject, more or less, to migration, in order to gain their free habitation in the alimentary canal of animals, where their segments ac- quire the male and female generative organs. The fecundated ova, produced in enormous numbers from each segment, do not in general, so far as is known, become developed into embryoes in the intestine of the animal in- habited by the Cestoid, but are evacuated along with the faeces, either separately after being discharged from the oviducts of the Cestoid, or before their discharge by the disjunction of the more ripe terminal segments from the rest of the animal. The migrations to which the ova and young of the Taenioid animals are thus made subject have hitherto opposed so great an obstacle to the observa- tion of their development, that we are as yet in possession of very few continued series of observations in which the whole progress of development from the ovum to the complete segmented animal has been traced. Some important contributions of this kind have, however, recently been made, and the great modifications which the views of comparative embryologists have undergone, from the novel and various aspects in which many of the phenomena of development are to be regarded in instances of alternate generations, have already indicated paths of inquiry by which this very curious and intricate history may ere long be completely unravelled. The ac- companying figures from Dujardin's work show the progress of formation of a small Taenia inhabiting the Shrew, and give a suf- ficiently good idea of the nature of this pro- cess in a Taenia, which consists of compara- tively few segments (Jig. 96. a to z.). Von Siebold has traced with care a part of the process of development of a minute Cestoid inhabiting the pulmonary sac of the red snail (Arion empiricontm) in the encysted condition. Into this situation the minute Taeniae are introduced from the exterior : they consist of the head with its double circlet of ten hooks each, and four suckers, and a body which is at first entirely destitute of segments, not longer than the head, and form- ing a soft vesicle, within which (as in other * Von Siebold proposes to substitute the genus Tetrarhynchus for the following five genera distin- guished by Dujardin, viz., Rhynchobothrius, Antho- cephalus, Tetrarhynchus, Gymnorhynchus, and Di- bothriorhynchus. Zeitsch. f. Wiss. Zool. 1850, and Ann. des Sc. Nat. 1851. Cystic Entozoa previously mentioned) the head is retracted, so as to give the whole a globular shape. V. Siebold regards it as nearly certain that these minute Taenia? only attain to their segmented and complete sexual condition when they have been located in the alimentary canal of Vertebrata (Birds and others) preying upon the snails in which the younger forms of the Taenite reside. Development of Tcenia pistillum of the Shrew. {From Dujardin.} a, embryo within the ovum, just about to quit it, with three pairs of hooks ; b, embryo that has left the ovum, the hooks capable of rapid and exten- sive movements ; c, embryo moving freely (of the Taenia serpentumm of the magpie) ; d, e, very young embryoes of Taenia pistillum ; /, g, h, i, different stages of growth of this Taenia ; the separation of the segments gradually increasing, and the develop- ment of the reproductive organs in the posterior ones ; k (more magnified), the proglottis, or free moving separated segment of this Tamia. OVUM. 29 The instance already referred to, of the iden- tity of the Cysticercus of the liver of the mouse and rat with the Teenia crassicollis of the cat, and a variety of detached observations which prove that the Bothriocephalus and Tetra- rhynchus pass through similar changes from a small Echinococcus-like animalcule to the developed cestoid form, lead to the corro- boration of the same general view that the encysted condition of these Entozoa is an incomplete non-sexual embryo or larva, from which, when it passes into the free state, there is formed by a process of transverse Fig. 27. Tasnla solium. (From BlanchardS) A, one of the longer mature posterior segments with the sexual organs fully developed ; o, o, rami- fied ovary full of ova ; o', the oviduct ; t, the tubu- lar testis ; t', the penis, &c. B, head, neck and anterior recently formed seg- ments. fission a segmented individual or compound animal, in which each segment, as it arrives at maturity, attains to sexual completeness. In this process the new segments are always developed between the head and those already formed. If the character of sexual complete- ness is to be taken as the distinguishing mark of individuality, each segment of the Cestoid may be looked upon as a distinct animal, and the separation of them by transverse fission may be compared to the separation of Medusa individuals from the Strobila polype stock. The Cestoid Entozoa might in the same manner be considered as subject to a peculiar process of alternate generation. In the preceding sketch of the nature of the reproductive process in the Cestoid Ento- zoa, I have followed chiefly the views of V. Siebold as explained in the interesting Me- moir already referred to. It is right to state, however, that the phenomena have been viewed in a different light by several observers of high authority. Thus, Blanchard and Van Beneden consider the first stage of the Tetra- rhynchus-embryo to be a Scolex, in which, after it has been encysted, the Tetrarhynehus is formed : this, according to Blanchard, is its complete condition ; but, according to Van Beneden, the so-called Tetrarhynehus is con- verted into a Rhynchobothrius, and this is in the last place changed into a separate Tre- matode animal.* Dujardin had previously taken the same view as applied to the separate and independent nature of the joints of the Taenia, which he regarded as individual Tre- matode animals, and described under the name ofProglottis(seet/?g.26.^.)f ; but though there may be some points of analogy between the single segments of Taenia and a Trematode, yet the absence of head, differences in the alimentary canals, and other circumstances, render the correctness of this view, at all events, still doubtful, i Trematoda. — These animals, the most common of which are known as Flukes (ex- cluding the Planariae), comprehend a set of internal parasites of a structure bearing some resemblance to the Cestoidea, but single, that is, not jointed or segmented. The nervous and vascular systems attain to a considerable degree of development : the alimentary canal, which has a mouth but no anus, is in some bifurcated, and in others more or less ramified. The male and female generative organs are united in one individual, and pervade a large portion of the body of the adult animal. The facts which have been ascertained in recent times concerning the generation of some of the Trematoda constitute one of the most remarkable parts of the history of this process among the Invertebrata. Their ge- neral result may be shortly stated thus : — the fully grown and sexual Trematode animal, as observed chiefly in the Distomata, produces ova, which may pass through the earlier stages of their development either in the viviparous or oviparous mode, more fre- quently the latter. Each of these ova has formed from it an embryo in which no re- semblance to the Trematode parent is to be recognised, but presenting the simple struc- ture of a ciliated animalcule like a polygastric infusorian or a Gregarina. This embryo is * Bull, de 1'Acad. Roy. de Belgique, 1849, No. 1., and Ann. des Scien. Nat. vol. xi. 1849, p. 13. ; also a work by the same author on the Entozoa, Brussels, 1850, of which I have only seen an extract in a letter addressed to Milne-Edwards, in the Ann. des Scien. Nat. 1851. torn xv. p. 309. t Hist. Nat. des Helminthes, 1845. j See also Leblond, in Ann. des Scien. Nat. 1836, and Miescher, Bericht Naturforsch. Gesellsch. Basle, 1840 ; the Works of Rudolphi on Entozoa; the Article ENTOZOA in this Cyclopaedia, by Owen; Kblliker's Memoir on the Development of Inverte- brate Animals, in Miiller's Archiv, 1843 ; Eschricht on Bothriocephali, 1840, &c. &c. 30 OVUM. not itself converted by any direct process of development or metamorphosis into a perfect Distoma, but lias gradually formed from germ- cells within it a progeny, sometimes of one, more frequently a number of bodies, which, when they arrive at maturity, present each one an external form and internal structure and locomotive powers, entitling them to be con- sidered as independent animals. Nor are these directly converted into Distomata ; but again there is formed within the body of each, and in the same gradual manner from germ-cells, a new progeny of animals nearly similar to those producing them and equally differing from the complete Distomata. Each of this new progeny, as it increases in size, has formed within it by development from germ-cells the third progeny of the series, and the last of the cycle ; but these are different from their immediate parents, and in their internal or- ganisation soon manifest the type of the true Trematode. These animals are endowed for a time with very active locomotive powers, to which a long caudal appendage con- tributes ; their two progenitors have been confined in the parasitic condition, but these Fig. 28. Series of changes in the development and generations of Distoma. (From Steenstrup.~) o, Ovum with embryo or larva developed in it. e, this embryo in a free moving state ; e>, another embryo in its interior. (These are of Monostomum mutabile, from V. Siebold.) E, this last embryo farther advanced. 1, first stage, soon after it becomes free ; 2 and 3, farther on, with g, the second generation, within them in various stages. G, 1, one of this second generation at an early period of its advancement ; 2 and 3, farther on, with c, c, Cercariae or Distoma-larvae, within them ; g', one of the granular globules from which the Distoma larvae and previous generations arise near the posterior part of the body. c, one of the Cercariae or Distoma larva with its caudal appendage, p, the same, passed into its en- cysted or pupa state, having previously lost its tail. D, Distomata. 1, young Distoma immediately after it has quitted the cyst, and has penetrated a short distance into the body of the snail ; 2, Distoma found deep in the viscera. are in general freed from confinement, and move about with great vivacity for a time in the water surrounding the animals which their progenitors have infested. In this state they have long been known as Cercariae, and as they have been supposed to be the young of Distomata, have attracted peculiar notice among Helminthologists.* The free Cercariae are not, however, directly converted into Distomata; but appear always to undergo a previous metamorphosis in a chrysalis state, or enclosed in a pupa cyst. * Kitsch, Beitragzur Infusorienkunde, &c., Halle, 1817; Bojanus, in Isis, 1818; A remarkable and interesting series of papers by V. Baer, in Nov. Act. Nat. Curios. 1826, vol. xiii. ; Rud. Wagner, in Isis, 1834 ; V. Siebold, in Burdach's Physiol. vol. ii. of German edit. p. 187., or vol. iii. of French transl., p. 32., &c. Previous to the formation of this cyst the Cercarise adhere to, and bore into, the sub- stance of the animal infested by the Disto- mata; the tail is cast off, an exudation from their own bodies forms the cyst, which en- closes them : within this they remain for many weeks, and even months, moving all the while, and undergoing changes of develop- ment, by which they are at last converted into the complete Distoma. The greater number of the observations from which this remarkable process of gene- ration has been ascertained to occur are due to V. Siebold and Steenstrup ; but the whole succession of changes has not yet been ob- served in any one species, and it is to the latter observer especially that the scientific world is indebted for the ingenious com- bination and interpretation of the scattered OVUM. 31 observations of previous inquirers, as well as the addition of new facts, from which an almost entire certainty is acquired that the various phenomena do actually succeed each other in the order above stated, and that the occurrence of alternate or intermediate gene- rations in these animals is established. Von Siebold had in 1835 described in the Monostomum mutabile the development of the first embryo from the ovum in the Gregarina- like or animalcular form, and had shown the next change to consist in the formation within the first embryo of a second body endowed with locomotive power, and independent vita- lity, and differing both from its immediate parent and from the acKilt.* V. Siebold, as well as others, had ascertained the Cercariae to be themselves incomplete animals, and to proceed from others by a process of internal production of a non-sexual kind. Steenstrup therefore di- rected his attention particularly to trace these Cercariae on the one hand, in their development into complete Distomata, and on the other, backwards through their progenitors towards the first origin from an ovum. His observa- tions were made principally in three kinds of Cercaria, which, along with their antecedent and succeeding conditions, are found in great numbers in the fresh water snails, Lymneus stagnalis, Paludina vivipara, Planorbis, &c., and which had been previously named Cer- caria echinata, C. armata, and C. ephemera. In these, especially in the first, the conversion of an encysted Cercaria by metamorphosis into a Distoma, and the descent of the Cercaria (by metagenesis) through two progenitors, not themselves Distomata, was ascertained, but he did not succeed in tracing these bodies back to their origin from ova. By a com- parison, however, of the body formed within the animalcular embryo of the ovum of the Monostomum mutabile, as observed by V. Siebold, with the first progenitor of the Cerca- ria, to which it was found to present a remark- able similarity, the chain of evidence seemed to be complete, and Steenstrup found himself in a position to announce the general views of alternate generation, which have ever since their first publication attracted the greatest attention, and contributed in a powerful de- gree to modify and direct the investigation of the generative processes in the lower animals. To the immediate progenitor of the Cercaria Steenstrup gave the name of nurse (altrix, Amme), in allusion to its nursing or nourishing function, and to the immediate progenitor of this one he gave the appellation of " parent or grand-nurse." These terms may be objection- able, but an unnecessary amount of criticism seems to have been bestowed on them by some writers. They are adopted hypotheti- cally by Steenstrup ; they do not appear to withdraw him from the matter-of-fact state- ment of his observations; and they seem to be, in many respects, short and convenient terms in the description of the phenomena. These bodies have in the Cercaria echinata all the appearance of distinct animals, that is, a * See Wiegmann's Archiv, 1835. body with a head separated by a neck or col- lar, a tail or caudal projection, and two pro- cesses of the integument similar to limbs, a mouth and alimentary cavity, and they move with all the appearance of spontaneity ; but it ought to be remarked that the form and powers of these nursing or formative cases differ considerably in various other species, and in some present so little of the external form or endowments of an independent ani- mal, that the more general appellations of germ-cases, or germ-sacs, or sporo-cysts, may be more appropriate to them.* It is chiefly among the aquatic Gastero- pod Mollusca, and a few land ones, that these observations have been made ; but V. Siebold has extended them to some of the Trematoda inhabiting the air-sacs and other parts of water fowls, which no doubt come from the same Mollusca, and obtain access to the seat of their final parasitic habitation from the water or along with food, into which they have come as Cercaria?, after having previously been parasitic in the Mollusca. It is easy to understand how the ova of the Distomata discharged from the bodies of the water fowl may gain their place in the Mollusca. V. Siebold has observed in a very interesting manner also the passage of the Cercariae into the bodies of water insects (larvae of Ephemera and Perlida), which he placed together with a quantity of Lymneus stag- nalis, from the various parts of whose bodies the Cercariae were discharged in numbers out of their nursing capsules : the penetration of the integument of the insect by the Cercaria and the mode of casting its tail being precisely the same as that observed by Steenstrup in the Mollusca.f Both these observers agree that the first and second germ-cases (or nurses), and the Cercariae, or Distoma-larvae, arise by a process of gradual development from extremely minute granular spherules, which are at first situated in the posterior region of the body, or between the alimentary cavity and the integument. These are certainly not ova : but we are at a loss to state to what class of reproductive germs they may be referred with greatest accuracy.:}: It is known that the bodies which inhabit the aqueous chamber of the eyes of many fishes are imperfect Distomata. Steenstrup has frequently observed these larvae in the pupa state adhering to the inside, and some- times to the outside, of the cornea, and he has occasionally noticed a delicate streak through the cornea, indicating the track through which the animal has penetrated ; and he considers it as extremely probable that all the Trema- toda of the eyes of fishes, of which a vast variety has been described by Nordmann$, are * See Victor Carus, iiber den Generations -wechsel, for a figure of these more simple forms of sporo- cysts. t See the Article PARASITES, in R. Wagner's Handworterbuch der Physiologic. t See Fig. 28. , only half round the ovum ; g. germinal vesicle. two kinds of organised particles, — viz., of smaller granules nearly similar to those which form the whole yolk in the last group, and of larger cells, usually non-nucleated, and fat vesi- cles, which constitute the greater part of the mass. The first or granular part of the yolk constitutes a thin disc, limited to one region of the surface, — viz., the upper side in the vicinity of the place occupied by the germinal vesicle, while the cellular substance of the yolk forms the larger spherical mass of the egg. Besides these two, there are also various intermediate forms, which seem to be stages of transition between the other kinds of struc- tural elements. ripe ovarian ovulum, is situated in the centre of the granular disc, and after its disappear- ance, the process of segmentation is limited to that disc. The germinal or blastodermic mem- brane, or layer of cells, extends, therefore," at first, no farther than this granular disc, and consequently it is only a very small part of the ovum which directly contributes to lay the first foundations of the embryo, or its accessory parts ; while the larger mass of cellular yolk comes only secondarily to take a part in the process of embryo nourishment. Hence, in such ova, the distinction may be broadly drawn between the germinal or for- mative, and the nutritive parts of the yolk. Such is the invariable relation of the parts of the ovum to development in the whole class of birds, with some differences in scaly rep- tiles, in cartilaginous fishes, and perhaps also in cephalopodous mollusca, and a few other invertebrata. Third group. — In another group of animals the structure and relations of the parts of the ovum are different from, but in some degree also intermediate between, those of the two groups previously described. In this one the yolk, or ovulum, may be stated to be of middle size ; its structural elements appear to be of two kinds, — viz., the smaller germinal or formative granules, and the larger, or nutritive corpuscles ; but these last are in less quantity, are subject to considerable variety, and exhibit less of the cellular structure which characterises the ova of the previous group. The germinal layer occupies a larger portion of the surface of the yolk than in the large-yolk ed ova (second group), but in ge- neral less than in the small-yolked ova (first group), and its extent is subject to consider- able variety ; in some, covering not more than a half, in others, extending nearly over the whole surface of the yolk. The segmentation is co-extensive with the germinal part, and more or less of the yolk, therefore, contributes at the first to form the primitive parts of the embryo. Such is the condition of the ovum in the Scaleless Reptiles or Amphibia, and Osseous Fishes. The ova of the higher Crus- tacea, Arachnida, Insecta, and some other Invertebrata may perhaps be included in the same group. It will be perceived that in the three groups now mentioned, a distinction has been drawn between a part of the yolk, which is imme- diately employed in the formation of the em- bryo, and another, which is only remotely connected with that process. In the bird's egg, it has been stated that the latter part of the yolk is in large quantity, and that in the minute mammiferous ovum the first part only exists, and that in batrachia the two kinds of yolk substance are more nearly equally ba- lanced. This difference among the ova of animals has been long known to physiologists in a general way ; but its true nature, as con- nected with a difference of structure of the two kinds of yolk substance, and their relation to the earliest development of the embryo, has OVUM. of late attracted considerable attention, and appears to have been first clearly stated by Reichert in 1840, and afterwards in 1843 * ; and in accordance with the views of that au- thor, we may with propriety distinguish the formative (or germinal) from the nutritive parts of the yolk. In the fowl's egg, for ex- ample (in which it must be admitted these two parts were long confounded together), the cicatricula, together with its so called nucleus, and a part, perhaps, of the lighter- coloured substance which occupies the centre of the yolk and the canal extending from it to the cicatricula, constitutes the formative or germinal part ; and the larger mass of the more deeply-coloured portion of the yolk forms the nutritive vitelline substance. In the mammiferous ovum, on the other hand, the latter part is either entirely absent, or is in small quantity, and the whole of the yolk substance may be looked upon as directly formative, or as analogous to that which forms only the cicatricula of the fowl's egg. Among more recent writers the distinction of these parts has been particularly insisted upon, and illustrated by M. Costef, and also by Messrs. Prevost and Lebert.J The difference in the relative amount of the formative and nutritive yolk substance, as well as in the size of the whole ovum, in birds and mammalia, is manifestly to be regarded as more immediately connected with the dif- ferent manner in which the embryo is to be supplied with the materials necessary for its growth in the two cases ; in the oviparous mode of development, the whole amount of nourishment required being provided in the egg itself, and detached along with it from the parent ; in the truly viviparous mode, a con- tinual addition of new materials for growth, being made by transmission from the maternal parent in the placenta, or in some analogous structure, which accompanies utero-gestation. The smaller proportional size of the nutri- tive part in Batrachia and Osseous Fishes (though most of these animals are truly ovi- parous), may be attributed to the very early period of development, and consequent small size of the embryo at the time when in these aquatic animals it leaves the egg, and, taking upon itself an independent life, gathers nou- rishment in the same manner as the adult animal. $ * Entwickelungsleben im Wirbelthierreich ; 4to. Berlin, 1840 ; and in Beitrage zur Kenntniss des heutigen Entwickelungsgeschichte; 8vo. Berlin, 1843, p. 22. t Cours d'Embryoge'nie Compare'e, torn. i. Paris, 1837 ; and Histoire gen. et partic. du Developpement de PHomme et des Animaux, Paris, toin. i. 4to., 1848. t In Anna!. 'des Scien. Nat. for 1844. 3rd Ser. torn. i. p. 193 and 265. § At the same time it is to be kept in mind that there are exceptions to these relations, which make it extremely difficult to state any general law of connection between the structure of the ovum and the mode of gestation and place of development of the embryo ; as in the case of a few of the lizards and serpents, and some cartilaginous fishes, in which although the egg agrees in general structure with The above arrangement is by no means offered as exhausting the divisions which might be formed of the ova of animals, but rather as bringing forward prominently the most remarkable characteristics of those of vertebrata. It is not improbable that a more accurate acquaintance with the structure of the ova in the animals thus grouped, and more especially of the In vertebrata, may lead to some considerable modifications of the divisions here adopted; but the main distinction upon which they are founded is so important, that even with our present incomplete acquaintance with them, it seems advisable to call attention to it at this place. As I shall have occasion to refer frequently to these groups in the sub- sequent description of the ova of various animals, in the absence of more appropriate appellations, I will, for the sake of brevity, designate them severally, as follows, — viz., 1st group, Small-yolked ova, as in Mammalia ; 2nd group, Large-yolked ova, as in Birds, Scaly Reptiles, and Cartilaginous Fishes; 3rd group, Middle-sized yolkcd ova, as in Batrachia, Os- seous Fishes, &c. § 2. Further comparison of the ova of animals in general, as respects their size, number, form, and the relation of their parts. Size of ova. — In addition to what has been said on this subject in the previous section, it may farther be remarked that, in the second and third groups, the size of the ova of dif- ferent genera and species is to a certain extent proportional to that of the adult animal, or of the fully-developed foetus; but in the first group, or at least in Mammalia, in which the nutritive part of the yolk may be considered as wholly or nearly entirely absent, there is a much greater uniformity in the size of the ova; and, accordingly, the largest mammi- ferous animal may take origin from an ovum which, when mature, is even smaller than those of species of animals many hundred times less in bulk ; while in the class of Birds we observe the nearly regular increase of the size of the ovum in proportion to that of the parent animal, from the smallest hum- ming bird up to the ostrich, or the still larger egg of the ^Epyornis, an extinct bird, of which some of the bones, along with the eggs, have recently been discovered in Madagascar.* that of animals which are generally oviparous, it is retained in the oviduct or uterus of the female during a part or even the whole of the time of foetal develop- ment; and there are also exceptions in the." third group — viz. that of batrachia and osseous fishes as in the Land Salamander and Viviparous Blenny. To this mode of gestation the name of Ovoviviparous has been given. There are many varieties of a similar kind among the Invertebrata, and on the whole it may be stated that there is no constant correspondence between the size of the ovum and the mode of gestation. The Marsupiata also, and the Monotremata among the Mammalia, exhibit interesting modifications, in the first a partial, and in the second, probably a complete residence of the ovum in the uterus of the female parent during de- velopment; while the ovum in these animals ap- proaches, in some respects, the type which is more commonly oviparous. * The circumference of this extraordinary egg OVUM. 49 In illustration of the most striking of these differences of size in the ova of animals, the following examples may be referred to : — The human ovum is a body not more than a.iu- of an inch in diameter ; so minute, in fact, that we can scarcely form any estimate of its weight or quantity of matter. Let us assume, what seems probable, that it weighs about -j-J^j. of a grain. Now, if we take the weight of a full-grown foetus as between six and seven pounds, or 45,000 grains, and the adult human body as about 120 or 130 Ibs., or 900,000 grains, it appears that while the full- grown foetus bears the proportion of one- twentieth of the weight of the adult, the ovum is scarcely a thousand-millionth part. In the fowl, the entire egg, when newly laid, weighs about 2 ounces, or 900 grains, and is nearly one twenty-second part of the weight of the adult body, supposing it to be some- what under 3 Ibs. The chick, produced by incubation, is about 600 grains in weight, or about two-thirds of the egg, and is, there- fore, somewhat less than a thirtieth part of the weight of the adult. Again, let us take the weight of an osseous fish (as in a female cyclopterus lurnpus recently measured by myself), at 9 Ibs. 8 ounces, or 66,500 grains ; one of the ova, which were fully developed and filled two enormous ovaries, weighed one- seventh of a grain ; and the foetus of such a fish, when it first leaves the egg, might pro- bably weigh not more than one-tenth of a grain ;so that the egg would be in the propor- tion of 1 to 500,000, as compared with the body of the fish. It is to be observed, however, that this great disparity of size belongs principally to the nutritive part of the egg, and that there is a nearer approach to uniformity in the size of the germinal vesicle ; but in this, too, we shall afterwards see that the size is greatest in the ova of the second group, in which the whole ovum attains the greatest magnitude. In the mammiferous ovum, the germinal vesicle is about -g±-Q or ^i_ of an inch in diameter ; but in the fowl's egg it is of a diameter about ten times greater, and in cartilaginous fishes it is even of a somewhat larger size ; but still in no egg does this vesicle depart altogether from that small and almost microscopic magnitude which may be regarded as characteristic of the elementary organic structures. The size of the ovary, when full of developed ova, is also deserving of notice, as giving some over its long diameter, is stated to have been nearly three feet, and over its short diameter two feet four inches ; its greatest length nearly thirteen inches. M. Isidore Geoffroy estimates that it must have contained 10£ qua'rts of substance, or nearly six times as much as an ostrich's egg, 148 times as much as an ordinary hen's egg, and 50,000 times as much as that of a humming bird. Notwithstand- ing, however, that in the class of birds there is a general correspondence between the size of the egg and the stature of the adult, this correspondence is not regular or constant, and Prof. Owen has illus- trated this fact in a striking manner by reference to the Apteryx of XP.W Zealand, which produces a proportionally very large egg. indication of the relative amount of repro- ductive power in the three groups before dis- tinguished. Thus, in the human species, the two ovaries weigh about 500 grains ; in the fowl, when developed at the breeding season, the ovary, with its yolks, may weigh 1,500 grains ; and in the lump fish, above mentioned, the ovaries weighed together 3 Ibs. and 3 ounces, or 22,300 grains. Thus the ovaries were to the body, in the first, as 1 to 1,800 ; in the second, as 1 to 13 ; and in the third, as" 1 to 3.* The following table may serve to exhibit these proportions in a general way : — Weight in Grains of the — Ovum. Ovaries. Foetus. Adult. Mammifer - 0001 500 45,000-0 900,000. Fowl - - 900-000 1500 600*0 20,000. Osseous fish - 0-135 22,300 O'l 66,500. Number of ova. — The number or quantity of the ova which the females of different animals are capable of producing in a given time, or during the whole of their lives, is so various, that only a very vague statement can be made in regard to it. The very great pro- ductiveness or fecundity of osseous fishes, and of many of the invertebrata, is well known. The ovary of the herring has been found to contain 25,000 ova. In the Cyclopterus lumpus, before referred to, the number of ova estimated as being contained in the ripe ovaries together was about 155,000; and in the ovaries of a Holibut or Hippoglossus, of 156 Ibs. weight, I found about three and a half millions. The queen ant of the African termites is said to lay 80,000 eggs in 24 hours ; and the common hair worm, or Gor- dius, as many as 8,000,000 in less than a day. The Entozoa appear to produce the greatest number of all animals — a fact which is somewhat surprising, when we consider how few of these animals comparatively reach their adult condition. In many of the above animals this enormous production is not a single act, but is repeated again and again in successive seasons. In birds and those animals belonging to the second group, in which the eggs are propor- tionally of large size, comparatively few of the ova, of which the germs are visible in the ovaries, come to maturity ; and in the natural state only a small number are productive. But it is well known that great variations may be caused in this respect by the condition of the animal ; and that in a state of domesticity, and under high feeding, a much greater num- ber of eggs may, in some birds, come to ma- turity, as in the common fo\vlt in some kinds of which, indeed, an egg is laid daily for two- thirds of the year — a production which would amount to upwards of 30 Ibs. or ten times the weight of the whole animal ; and, if * The Article "Zeugung" by Leuckart, con- tained in two parts of K. Wagner's Handworterbuch der Physiologic, and which I have only received since the above was written, may be consulted as containing fuller information on the same and the following subject. 50 OVUM. the product of different successive years be taken together, a fowl may, at the most, bring forth about 1,200 eggs. I have attempted to count and estimate the whole number of ovula in the undeveloped state to be seen in the ovary of the common fowl, and I find it to amount to 30,000 or 40,000. A great many of these ovula must, therefore, be unproduc- tive in the higher oviparous animals, their germs either remaining undeveloped or being absorbed in the ovaries. In mammalia, and in the human species, although only a few ovula approach to maturity at a time, and a small number only of the ova, as compared with the whole of those contained in the ovaries, serve for pro- duction of the offspring, it is known that a considerable number is discharged from the Graafian vesicles of the ovaries in the unim- pregnated state. Thus, in the human female (as will be more fully stated hereafter), one or more ovula are discharged from the ovarian vesicles at every successive four-weekly men- strual period during about 30 years of life, and thus not less than 400 ovula may be ex- cluded from the ovaries ; but this number is probably greatly below that of the whole ovula or their germs, which the human ovaries contain ; and the ovaries of many quadrupeds present, undoubtedly, a greater number. External form and relation of the parts. — The ovum, being composed of cellular, gra- nular, and fluid substance, and being enclosed by an entire vesicular membrane, has gene- rally, at least in its early condition, a spherical form. In the mature state, this form is in many instances retained ; but there is also not unfrequently a departure from it, in conse- quence of the addition of the external parts unequally deposited on the surface of the more globular yolk within them. This sphe- rical form of the ovarian ovum points to its isolated mode of production, and its destina- tion for a separate existence, and is character- istic of the elementary nature of its organic structure. In the class of birds, the egg is always covered in by an external hard calcareous shell ; and in the greater number the external form given by this is somewhat elongated, and not unfrequently, as in the common fowl, with a difference of the size and curvatures at the opposite ends, caused by the manner of the descent through the female passages. There are, however, considerable differences among the different families of birds, as in the nearly globular form of the predaceous, the more elongated form with nearly equal ends in some of the ducks, the well-known shape of the gallinae and others allied to them, and the greater disparity at the opposite ends, as in the seafowl.* [n those of the scaly reptiles which are oviparous, there is also a firm external cover- ing ; but only in some of them, as in most chclonia and in the crocodiles, is there a hard * See on this subject the works of Hewetson and others. calcareous shell. In the greater number of the sauria and ophidia, the external covering is of a tough membranous or parchment-like consistence, formed of several layers of con- densed fibro-alburninous substance, in which either no calcareous matter, or only a small quantity of it, is contained. In those serpents and lizards, again, which are ovoviviparous, the egg, when it descends into the oviduct, is not covered there with the firm external en- velope, but with a thinner and softer mem- brane, similar somewhat to the membrane lining the shell in birds. External forms of different eggs of Birds and Reptiks. A. Batrachian reptile, frog or toad; spherical shape, the dark yolk within, the gelatinous albumen externally ; swollen by imbibition of water. B. Triton or Salamander; elongated external membrane, coloured spherical yolk within. c. Oval of unequal curves at the two ends, as in gallinaceous, passerine, and many other birds. D. Very unequal size of the two ends, as common among sea-fowl. E. Equal oval, as among some ducks, the crocodile, lizard, &c. F. Short oval or nearly spherical, as in predaceous birds, chelonia, &c. In the oviparous cartilaginous fishes, a peculiar horny capsule is formed round the yolk and albumen, as they pass through the oviduct at a place where a particular gland is provided for its formation. These capsules are of a fibrous structure, of an oblong, some- what quadrilateral shape, as in the skate and shark, and, at each angle, are prolonged into tubular processes or filaments, of great length in some sharks, which when short and open, may allow of the passage of water to the embryo contained for a long time within the ovum; and serve also the purpose, when long and convoluted, of entangling and attaching the egg capsule among seaweed and floating bodies. I have found that in the Myxine glutinosa the globular yolk is enclosed in a horny cap- OVUM. 51 sule of similar consistence and structure, but of a simple elongated ellypsoidal shape, and in place of four terminal angular tubes, a number of trumpet-shaped tubufar processes project- ing from the middle of the two ends, which probably serve the same purposes as the differently shaped appendages of the ova of the shark and skate. Fig. 33. T) External form of ova of Oviparous Cartilaginous Fishes. A. Ovum of the common skate fish, a portion re- moved from one side of the coriaceous envelope to show the yolk floating in the white : one-third the natural size. B. Ovum of the shark, squalus catulus, also opened : half the natural size. c. Ovum of the Myxine glutinosa, entire : natural size. D. Enlarged view of one of the 2£— 30 tubular funnel-shaped processes from the same ovum; the attached end is at D. In birds, it is well known that the yolk and germ, with their enclosing vitelline membrane, are produced in the ovary, while the albumen, chalazae, membrane, and shell are more rapidly formed and are added during the passage of the egg through the oviduct. It is by an entirely similar process that these accessory parts are formed in the scaly reptiles, the eggs of which agree with those of birds in the most essential points. The albumen, however, is generally in less quantity and softer, and the twisted chalazae have not been observed. The mem- brane which immediately covers the albumen has the same structure'as that of the bird's egg; and the calcareous shell, when it exists, as in turtles and crocodiles, is more porous and thinner. In cartilaginous fishes there is also a glairy albumen investing the yolk, and secreted from the oviduct. In most animals of the second group, or with the large-yolked ova, the vitelline substance consists almost entirely of oily and albuminous matter enclosed in or- ganised cells, the nature of which differs, as previously explained, in the vicinity of the germ and in the other parts of the yolk ; this substance contains, besides, the peculiar co- louring matter which has given the name to this part of the egg. In all of them a cicatri- cula exists, which is the seat of the germinal vesicle, and of the first formation of the rudiments of the embryo. The ovum of the frog, when newly expelled from the oviduct of the parent, consists of the yolk-ball, closely surrounded by a tough layer of peculiar albuminous matter deposited on it in the course of its passage through the oviduct. This substance has the property of imbibing a large, but yet a limited, quantity of water whenever it is immersed in it ; and thus, within a short time after the expulsion of the egg from the female, the external sub- stance has assumed a gelatinous consistence, ana has enlarged to such an extent as to be on every side equal in thickness to the dia- meter of the dark-coloured yolk within. I shall have occasion afterwards to state more particularly the important relation which subsists between this process of imbibition and the action of the spermatic substance in fecundation. In the common frog, the ova are thus united in large masses, floating in the water of stagnant pools or rivulets : in the common toad, they are united in long cords, which become entangled among aquatic plants. In the newts, the external covering of the ovum is membranous, homogeneous and transparent, and of an elongated oval shape, and there is merely fluid intervening between it and the spherical yolk and its membrane ; but when the ova are deposited by the parent in the folded leaves of water-plants or other situations, a small quantity of a peculiar glu- tinous matter, not readily acted on by water, is excreted along with the ova, which serves to fix the ova in a suitable place during the development of the young.* Various ex- amples of a similar kind occur among the oviparous animals of the invertebrata, more especially among insects and mollusca, when the ova are destined to remain exposed, and require protection during a considerable time before development takes place. In batrachia the yolk is variously coloured in different species : thus, in the common frog, toad, and some others, the surface or ger- minal part of the yolk is of a black or dark- brown colour, owing to a deposit of pigment granules in the cells of the germinal layer, while the remainder of the yolk internally is grey. In some other batrachia the colour is light brown. In the larger water-newt, or triton, the yolk is of a brilliant light yellow ; while in the smaller one, or lissotriton, it is * See the interesting description of this process by Rusconi, in Amours des Salamandres Aquatiques ; Milan, 4to. 1821. I have often confirmed his ob- servations on this process in ponds, and with animalg kept in vessels in the house. E 2 OVUM. ash-coloured. In the land-newt, which is oyo- viviparous, the yolk is of considerable size, and of a dark yellow, approaching to orange. In osseous fishes, which are almost all oviparous, the ovule receives, apparently in the ovarian capsule itself, before leaving that cavity, an external covering (or chorion) of considerable firmness. This membrane ap- pears to consist of a substance deposited on the external surface of the vitelline membrane, and becomes coagulated under the action of water ; so that its density increases greatly after the ova are deposited, while it is sepa- rated at the same time from the yolk by the imbibition of water. The ova are in spawning either deposited separately, or are united in chains or bundles, and in some less common examples* in peculiar nida- mental structures, more after the manner of some of the mollusca. The structure of the ovarian ovule, or yolk, and its relation to the germ, differs somewhat from that of the batrachia ; for while in the latter animals the yolk substance consists of granules and cells of nearly uniform size, and the germinal layer covers the greater part of the surface, in osseous fishes this layer is more circum- scribed, riot extending at first over more than a third, or, at most, a half of the yolk, and the remainder of the yolk, which contains a much greater quantity of transparent fluid than in most other vertebrate animals, presents al- most invariably a peculiar heap or mass of large oil globules, which float to the upper part of the fluid below the germinal layer.f The minute ovula of mammalia, when they have reached maturity in the Graafian capsules of the ovary, are nearly spherical bodies, of from T-LJ. to -jphr of an inch in diameter, and consist of a mass of finely granular yolk sub- stance, more loose in the interior and more dense towards the surface, and enclosed in a thick firm and transparent vesicular envelope, the vitelline membrane, or so-called zona pellucida. While still within the Graafian capsules, they occupy a situation near the most projecting part of the capsule, or towards the external surface of the ovary, being there imbedded in a layer of granular cells, the discus proligerus of Von Baer, which lines the ovicapsule, and lies on the exterior of the clear coagulable fluid with which this capsule is filled. A portion of this lining membrane of granular cells, remains adherent to the ovum after it leaves theGraafian capsule, and has passed into the Fallopian tube; but as it descends towards the uterus, these cells gra- dually loosen and fall away from the surface of the ovum, the zona pellucida or vitelline membrane of which is thus finally left free. In the farther progress of its descent, there is formed, in some mammalia at least (rabbit), * As Gobius. See Prof. Owen's Lectures on the Compar. Anat. and Physiol. of Vertebrated Animals, part i. p. 304. A. Hancock on the Nidification of the Gasterosteus aculeatus, &c., in Annals of Natu- ral History, Oct. 1852. t See a "paper by Dr. Davy on the chemical pro- perties of the vitellus of Osseous fishes in Trans, tfoy. Soc. for 1851. on the surface of the zona by a new deposit, in others, perhaps, by conversion of the zona itself, the external membrane of the ovum, which at a later stage constitutes the chorion. But, in accordance with the destination of the ovum in this tribe of animals for true utero- gestation, this external membrane has then no longer the character of mere inactive limita- tion of the exterior of the ovum, or defence from injury, which belongs to it in the lower animals ; but it becomes an organised and growing texture of active functions, which is the more immediate means of uniting organi- cally the blood-vessels of the mother and foetus, in such a manner as to allow of the transmission of nourishment from the one to the other. Varieties of form of the ova among the invertebrata are too numerous to allow of their being described in this place. In the greater number, an external envelope, besides the vitelline membrane, exists ; but it must be admitted, that there are some in which these two coverings cannot be distinguished. In some, as in insects, arachnida, polypes, &c., the chorion, or outer surface, presents pecu- liar markings, ridges, tubercles, or long spines, and is strong and opaque ; in others, it is Fig. 34. Ovum of Cristatella mucedo. (From Turpin, Annal. des Scien. Nat. 1837. torn, vii.) Showing peculiar spinous projections from the outer shell. smooth, delicate, and transparent, so as to allow the whole internal structure of the ovum to be seen through it, and thus to afford most favourable opportunities of wit- nessing the early changes of development. In most of the invertebrata the germinal part of the yolk covers the whole, or a con- siderable part, of its surface ; they present, however, great varieties of colour and struc- ture, and may, probably, belong to various modifications of the second and third groups before distinguished. It does not appear that any essential dif- ference has yet been observed in the structure of the ova of those animals which are subject to alternate generation, and those of animals in which the adult form is directly developed from the ovum. § 3. Of the ovary in general as the forma- tive organ for the ova of animals. OVUM. 53 The name of ovary is in all animals applied cle and enclosing membrane that is formed to the organ, however varied in its structure in the ovary, while the external or cortical and relations, in which the ova are formed, parts of the ovum are added to these in their As already indicated, however, it is to be descent through the female passages after observed, that in the higher animals, it is leaving the ovary. There are some examples only the ovule, or yolk, with its germinal vesi- in which it would appear that the whole Fig. 35. Relation of the ovaries, ovum, oviduct and uterus in Mammalia. A. Gravid uterus, &c. of the rabbit, ten days advanced in pregnancy ; a' a, right and left ovaries, four corpora lutea in the right, two in the left; b' b, fimbriated openings of tf c, the Fallopian tubes; did, the right and left cornua of the uterus; d', with four dilatations from contained ova, d, with two dilatations, one of which is opened to show the ovum ; e, the body of the uterus ; /, the vagina. B. A diagrammatic transverse section of the human uterus, at twelve or fourteen days after conception, somewhat less than the natural size ; e, the uterine cavity, near which the ovum with its villous chorion is involved in the substance of the decidua indicated by the dotted shading ; c' c, the Fallo- pian tubes cut short, by one of which the ovum had previously descended while still of small size. c. Enlarged view of the exterior of the human ovum, of twelve or fourteen days after conception, showing the villi of the chorion projecting from its surface. E 3 OVUM. formative process of the ovum, including the addition of the external coverings, is completed within the ovary; and, on the other hand, there are a few instances in which, as in the trematoua and cestoid en- tozoa, the germinal vesicle and yolk sub- stance of the ovule are formed in separate organs, instead of in the usual manner entirely in the ovary. The varieties of the ovaries in different animals may be considered under two heads — viz., 1st. Their relation to the passages or outlets as influencing the mode of discharge of the ova from them ; and 2nd, their internal structure as related to the form of the ovum produced. Fig. 36 Ovary and oviduct of a laying Fowl, killed twelve hours after laying the last egg. a. Left ovary ; b, opening of the infundibulum of the oviduct ; c, d, glandular portion of the oviduct ; at d, the isthmus ; e, an egg in the uterine portion of the oviduct, in -which the shell is begun to be deposited ; /, the rectum, ending in the cloaca ; g, the undeveloped right oviduct occasionally met with. a. Relations of the form of the ovaries to the discharge of ova. — In the majority of verte- brated animals the ovary or ovaries are quite detached from the conducting tube or ovi- duct ; the ovules are formed in close capsules of the ovary, by the bursting or fissure of the wall of which they escape ; the oviduct opens at its upper end into the abdominal cavity, and there receives the ovum which has been discharged from the ovary. This is the general arrangement in mammalia, birds, reptiles, am- phibia, and cartilaginous fishes. There is some difference in the form of the ovary in the higher and lower of these animals. In mam- malia and birds, in chelonia and the crocodiles among the reptiles, and in cartilaginous fishes the ovary is more or less solid, and the ovules are developed in capsules which project towards the external surface ; but in the lizards Fig 37. (.From Cams and Otto.) Female of the Falco buteo opened, showing the left larger oviduct and ovary, and the smaller right oviduct and ovary, of a, the right and left ovaries ; b, the left infundibulum ; c, d, the left oviduct ; /, the rectum, ending in the cloaca, which has been opened, showing at h> h the openings of the right and left oviducts, and at i' i those of the ureters ; g, the vestige of the right oviduct. OVUM. 55 and serpents, and in the batrachia, this organ is hollow, and the capsules in which the ovules are formed burst in dehiscence into an internal cavity, whence the ovules escape into the abdomen by the rupture or open- ing of the sack of the oviduct, generally at one, but sometimes, as in the frog, at a greater number of places. In the higher animals, in which the ovules escape from the external surface of the ovary, their en- trance into the oviduct is in general secured by the temporary apposition of the dilated upper end or infundibulum of the oviduct to the ovary, or the capsule containing a ripe ovule ; in the other animals, in which the ova come from the interior of the hollow ovary, the apposition of the oviduct does not ap- Fig. 38. Common adder, in which the ova have descended to occupy both oviducts, five in the right, and three in the left : the infundibulum is shown in each ovi- duct ; a' a, the right and left ovaries, each forming a sac, opening anteriorly near the infundibulum for the discharge of the ova, which, when ripe, fall into the interior of the sac, and thence pass into the oviduct. pear to be so direct, and there are various other means by which the ova, when they have escaped into the abdominal cavity, reach the open extremity of the oviduct. It is in the class of fishes that the transi- tion occurs from the higher to the lower type of organisation of the ovaries and oviducts. In all of them the ovules are formed in ova- rian follicles, and escape by dehiscence from these follicles ; but there are several modifi- cations of the relation between the oviduct and ovary among them. 1st. In the sharks and rays, as already stated, the arrangement is nearly similar to that existing in higher ani- mals. The ova, which are of large size, come to maturity singly, or in small numbers at once : on being discharged externally from the ovarian capsules, they pass into the oviduct, and there receive a considerable addition from this organ. The majority of them, as previously stated, are oviparous, and in them a hard covering is formed by a peculiar glandular organ connected with the oviduct ; in a few which are ovo viviparous, as the common dog- fish, torpedo, &c., the external covering of the ovum is membranous and soft. 2nd. In the sturgeon and in the lamprey the oviduct is very short ; still, as it opens superiorly into the abdominal cavity, the relation may be considered the same as in the previous ex- amples. 3rd. In the genus salmo and in Fig. 39. Ovaries and oviduct of an osseous Fish. A. Sketch of the two largely developed saccu- lated ovaries of an osseous fish, with 'the short ovi- ducts proceeding from near their posterior ex- tremities. B. Diagrammatic section of a portion of the ova- rian sac, showing two of the ovarian plates, from which the developed ova hang in small pediculated vesicles or ovisacs. E 4- 50 OVUM. the eel among the osseous fishes, the oviduct is entirely wanting, and the numerous ova, which are discharged by external dehiscence from the ovary into the cavity of the abdomen, escape from that cavity by an orifice (porus abdominalis) situated on each side close to the anus. 4th. In other osseous fishes, the ovary and oviduct are united, or the ovary forms a saccular organ, in the interior of the wall of which the ovi- capsules are situated, occupying a variable extent of it in different genera ; and the wall of the oviduct, usually very short, is continued from that of the ovary to the outlet from the animal's body. The ova, therefore, which drop by internal dehiscence into the cavity of the ovary, pass directly out by the short ovi- duct in the laying of the spawn. Most osseous fishes are oviparous; but in a few, as the viviparous blenny, the anableps, paecilia, and some siluroids, the ova, on escaping from their capsules into the cavity of the ovary, remain there during the development of the embryo. In the invertebrate animals there are very many varieties in the form and relations of the productive and conducting parts of the female generative organs. Three principal Fig. 40. Oviduct and ovary in a continuous tube in Insects and Entozoa. A. (From R. Wagner). Upper part of the ovi- duct or ovary of the Acheta campestris. B. (From ~H. Nelson.) Upper part of the oviduct or ovary of the Ascaris mystax. In both of these figures the germ-cells and germinal vesicles, with their nuclei, are seen surrounded by the granular matter which afterwards collects round them as vitelline or yolk substance. varieties may be distinguished among them 1st. A form similar to that just now described as generally prevalent among osseous fishes, in which the ovary and oviduct are con- tinuous, but in which the ova, being formed in ovarian capsules, are dropped by dehiscence into the upper part of the oviducts. Such is still the structure in cephalopoda and some other mollusca. 2nd. A form in which the oviduct may be said to be, as in the last, con- tinuous with the ovary, but in which there is no true dehiscence of the ovules from ovarian capsules, as they are formed at once in the internal cavities of the ovary, which directly open into, or are mere prolongations of, the oviducal tubes. In this form the oviducts may be considered to stand in the relation of excretory ducts to the ovarian glands. In many of this class the ovaries present very various forms ; in some the continuity of the ovarian and oviducal tubes is very obvious and simple, as in the ne- matoid entozoa, insects, &c. ; while in others, the ovary is more complex and race- mose, and the oviducal tubes comparatively simple. 3rd. That form in which the ovaries are variously disseminated over the body of the animals, and in which there are no true oviducts, but the ova escape on various parts of the internal or external surface of the body.* b. Structure of the ovaries themselves, as related to the production of the cvula. — In mammalia these organs consist of a pair of solid oval flattened bodies, attached by inter- vening fibrous tissue to the posterior surface of the broad ligaments of the uterus, and are covered completely, excepting at this attached part, by peritoneum. Below this serous co- vering there is also a layer of firm fibrous tissue, or tunica albuginea. The internal sub- stance, or parenchyma, or stroma, as it has been called, consists of a firm basis of fibro- cellular texture, of considerable vascularity. The fibres, as well as the blood-vessels of this substance, radiate principally from the at- tached border of the organ towards the oppo- site, or free side, and the rest of the surface. The ovicapsules, or so-called vesicles or fol- licles of De Graaf, in the human ovary, are situated in this stroma; and at or after the period of puberty are found of some size ; a variable number, from twelve to thirty, or more, being of from ¥V to i °f an inch, and a few even a little larger. These mem- branous vesicles, filled with fluid, are situated chiefly towards the surface of the free side of the ovary. A larger number of undeveloped capsules, of minute size, also exist in the * See Von Baer's Entwickelungsgesch. der Thiere ; Owen's Lectures on Invertebrate Animals, 1843, and on Fishes, 1846 ; Rathke (on Development of Fishes, &c.), in Geschjchte der Thierwelt, Th. 3. ; J. Miiller (on Sharks), in Mem. of Berlin Acad. 1842; John Davy (on the Torpedo), in Philos. Trans, for 1834; and the works of Von Siebold and Stannius, R. Wagner, Carus, and others on Compar. Anat. See also in this Cyclopaedia, the articles Monotremata, Pisces, Reptifia, and Organs of Ge- neration. 57 Relation of the ova and ovaries in Mammalia. A. (From Coste, as reduced by Longet.) Human ovary, enlarged four diameters, partially dissected at ooo, to show the Graafian follicles in the ovarian stroma : one of these, more advanced^ has had its double tunic, o r, cut into and reflected ; the granular membrane, m g, has also been partially opened, showing the thickened portion or granular disc, d g, in which the ovum is imbedded near the most projecting part. At o r', another Graafian follicle has been burst, and the ovum in its granular disc is seen expelled from it. B. Transverse section of human ovary, to show the general arrangement of the developed Graafian follicles towards the surface ; twice the natural size. c. Diagrammatic representation, in section, of two.Graafian follicles, in different stages of advance- ment in the ovary of a mammifer, enlarged about ten diameters, p. Peritoneal covering of the ovary, st, ovarian stroma; ov, the two layers of the ovisac; mg, membrana granulosa, near which is the discus granulosus, with the ovum imbedded. stroma ; and it has been observed, that these are present from a very early period in the ovaries, as first noticed by Cams, and since by myself and others in the child at birth. The more developed of these ovi-capsules are enclosed by a strong theca or membrane, consisting of two layers ; the external thinner and firmer, of a fibrous and vascular struc- ture, the internal thicker and softer, of a fibro-cellular structure and also of consider- able vascularity. The capsules are filled with a fluid nearly transparent, which coagulates under the action of heat ; and inside the theca, or lining it and covering the fluid, there is a layer of nucleated cells united together in the form of a soft, easily-lacerated membrane, somewhat like an epithelial lining of the cap- sule. It is in this cellular layer (tunica gra- nulosa of Von Baer) that the ovum is placed, being situated in the thicker portion of it (cumulus proligerus), directed towards the surface of the ovary. When one of the ovicapsules and its con- tained ovule has reached maturity, which takes place in one or more of them at regu- larly recurrent periods, besides the swelling of the ovicapsule itself from the increase of its fluid and other causes, the stroma of the ovary between the capsule and the surface undergoes considerable thinning, and the ovi- capsule comes thus to project more imme- diately from the surface of the ovary. An increased vascularity is also apparent in the same situation ; and finally a small circum- scribed fissure near the middle of the most projecting part occurs, allowing the escape of the ovule and the granular layer and fluid from the ovicapsule. The ovule, surrounded by a portion of the cellular layer in which it was embedded, is 58 OVUM. received by the open fimbriated extremity of the Fallopian tube. The empty ovicapsule now undergoes a remarkable change by the deposit in its inte- rior of the substance termed corpus luteum, the quantity and nature of which vary greatly according as the escape of the ovule is fol- lowed or not by pregnancy. Of this change more will be said hereafter. The result in both cases is the ultimate closure and obliteration of the ovicapsules. In birds, scaly reptiles, and cartilaginous fishes, the greater size of the ovules when in a state of maturity is connected with a modi- Fis. 42. Relation of the ova to the ovary in Birds. A. Ovary of a fowl, showing at a a a the most developed ova hanging from the ovary in their pedi- culated capsules ; the non- vascular bands are seen on their most projecting sides; at bb, the empty capsules or calyces of ova that have been previously discharged ; at c c, the more compact part near the root of the ovary, where the ova are less developed. B. Diagrammatic section of one of the most ad- vanced of the capsules ; o, the extended ovarian substance forming the capsule ; p, its pedicle ; c, indicates in this and the preceding figure the most common position of the cicatricula or germ-disc and vesicle; o v, the two layers of the ovicapsule or ovisac, into which the blood-vessels penetrate : the dotted line v m, marks the vitelline membrane. fication of the structure of the ovary and the ovicapsules. Previous to the age for breeding, the ovary of birds — in which animals only one ovary and oviduct is usually developed or attains to functional activity — is a solid organ of a less firm texture than that of mammalia, and is adherent to the vertebral column in the mid- dle of the dorsal region. It contains at an earlier period a much greater number of ovi- capsules of a considerable size than are per- ceptible in mammalia. The stroma or ova- rian substance is in less proportion, therefore, to the ovicapsules and ova. As the ovules become more developed, they increase rapidly in size ; and we then perceive that they bear a different relation to the ovicapsules from that which has previously been described in mammalia, as they fill com- pletely the ovicapsules, and there is no fluid or loose cellular layer between the outer sur- face of the vitelline membrane and the lining membrane of the theca.* As some of the yolks approach maturity their increase in size is proportionally much greater, and the theca or ovicapsule, and along with it the ovarian substance, is distended in like proportion ; and in this manner the ovary of the fowl at the breeding season has lost its appearance of compactness or solidity, and seems to be composed almost entirely of a larger num- ber of pediculated ovarian capsules of the most various sizes, filled with the yolks or ovules in all stages of development. Never- theless, a little attention shows the solid part of the ovary still remaining at the part at- tached to the vertebral column, forming the ground, as it were', from which the pedicles of the enlarged capsules spring, and contain- ing still a very large number of minute undeveloped ovules in their correspondingly small ovicapsules. The large ovicapsules of the developed ovary of the bird consist of two layers, which are loosely united together by blood-vessels and binding tissue towards the pedicle and over the greater part of the capsule, but are more firmly knit together at the free border. At the latter place the blood-vessels of the theca, which are on all the other parts dis- tributed in wide or comparatively large chan- nels very thickly set, suddenly become so small and delicate as to give, at first sight, the appearance of an absence of vascularity in the course of a band of about ^th of an inch in breadth, and extending across a large portion of the free circumference of the cap- sule.f This is the so-called stigma, at which, when the ovule is to escape from the ovary and to be transferred into the oviduct, the rupture of the theca occurs. * There may probably be an epithelial lining of this membrane. See H. Meckel's paper, afterwards referred to, Zeitsch. fiir Wissensch. Zool. vol. iii., 1852, p. 420. f The length of this band or stigma is about equal to the long diameter, or a third of the circum- ference of the capsule at its widest part. It is some- times crossed by a second band of the same kind. OVUM. 59 Each developed ovule, therefore, in these oviparous animals, comes to be contained in a pediculated capsule, which is formed by the extension of the substance of the ovary ; but from the great extent to which the dilatation of the capsule occurs, the true ovarian stroma is reduced to a very small amount, and scarcely more remaining than the theca of the capsule itself and the ovarian coverings. In the other animals possessing the large yolked ova, nearly the same structure of the ovary prevails. In chelonia and crocodiles, it is indeed almost identical with that in birds. In lizards and serpents, the hollow state of the ovary produces some difference in the general form ; and in cartilaginous fishes (sharks and rays) other differences in the structure of the ovary may exist ; but in all these animals the essential points of rela- tion between the ovarian substance and cap- sules, and the large ovules, are the same as that now described in birds. The lining membrane of the ovicapsule of birds is thick and tough, and on its inner sur- Fig 43. pta mil \ r- ^vfil fj% i to ;> Structure of the ovisac in the Fowl's ovary. A. Inner surface of a portion of the ovisac of a fully-developed ovarian capsule, magnified about six diameters, showing an appearance which might be mistaken for glandular depressions produced by the peculiar disposition of the veins. B. The same, from a calyx from which the ovum has been discharged some days before ; a whitish flaky membrane is deposited on portions of the surface. c. The same, from an undeveloped capsule of a quarter of an inch in diameter, across the stigmatic band. D. The disposition of the blood-vessels near the stigmatic band, which seems at first sight non- vascu- lar, but is in reality traversed by ramifying small vessels proceeding from the neighbouring larger veins, and crossing the stigmatic band. E. Two of the large mouths of the veins, which give the semblance of follicular pits represented in A and c, but which are quite closed, with the smaller vessels ending in them, as seen from the inner surface of the ovisac. face presents a soft appearance somewhat si- milar to that of a mucous membrane. In ex- amining the inner surface of this membrane, Dr. Sharpey and the author had their atten- tion arrested by an appearance such as might, on first sight, be attributed to a number of follicular or glandular pits. This appearance, as we first observed it, is represented in Jig. 43. (A, B, c) as it was seen in a fully-developed capsule — in one a third of an inch in diameter — and in a calyx from which the yolk had been discharged some days previously. We supposed, indeed, at first that the appearance depended on the presence of the orifices of follicular depressions or glands on the inner surface of the membrane. A more attentive examination of this membrane by Dr. Sharpey has shown that the appearance is not due to depressions of the inner surface of the membrane or to the mouths of follicles opening upon it, but is caused by a peculiar form of the blood-vessels seen through the entire and smooth inner surface of the mem- brane. The apparent depressions are in fact the sudden terminations or beginnings of veins of considerable size seen through a delicate and transparent portion of the membrane which closes them towards the inner surface. They may be made very obvious by merely coarsely brushing the smooth blunt edge of any instrument over the membrane, and thus causing the blood to flow from the vessels in other parts in these sinuses or dilated veins. It would appear that the smaller capillary vessels in which the arteries terminate, in ap- proaching the inner surface of the capsule, ramify with considerable minuteness, and at each of the marks or apparent depressions referred to suddenly fall into or end in the 60 OVUM. comparatively large veins which constitute the hollow spaces. The ends of these veins, then, look towards the inner surface of the membrane; and the appearance of a divided cavity in some of the supposed follicles is merely caused by two or more veins meet- ing in a common dilatation at this place. The capillary vessels, in passing into these large commencements of the veins seem to converge from its circumference to its centre. In the enlarged ovarian capsules of the turtle, a somewhat similar arrangement may be observed ; but I have not had an oppor- tunity of tracing its relation to the blood- vessels ; nor have I had the means of ascer- taining whether anything of the same kind exists in other reptiles with large yolks. In the skate 1 have not been able to perceive any similar arrangement ; and in the Graafian vesicle of mammalia the lining membrane presents internally a smooth surface destitute of any appearance of depressions or of pecu- liar venous sinuses. The appearance which I have just now described had not escaped the notice of Von Baer ; for at p. 23 of his work on develop- ment, he mentions the existence of clearer points in the inner membrane of the theca, and states his opinion that they may be open mouths of blood-vessels, by means of which the yolk may be nourished by the direct access of blood to it. In the naked amphibia and osseous fishes, the ovaries (of which the general form has been previously noticed) present a still greater decrease in the proportion of the stroma to the ovicapsules and ova. These capsules are themselves also of much more delicate struc- ture than in the higher animals ; but the rela- tion of the ovules to the ovicapsules in their formation, and the mode of their escape by the rupture of the theca, are essentially analogous to those of birds and reptiles. In the earliest condition, it is true, the ovary may present a greater amount of solidity in some of these animals : but from the prodigious number of the germs of the ovules and the small quan- tity of the ovarian stroma, as soon as the ovary has made some progress in develop- ment, it acquires the appearance rather of a mere mass of ova connected together by a membrane and fine thread-like pedicles, than of a solid or consistent organ containing them. The delicate ovicapsules containing the ovules embrace them closely as in the large-yolked group of animals, there being little or no fluid between the capsules and the vitelline membrane. The structure of the ovaries in the inver- tebrate animals presents so many varieties that it would occupy too much space to allude to them here. I refer the reader for information regarding them to the article ORGANS OF GENERATION, and others on par- ticular classes and orders of animals in dif- ferent parts of this work. For our present purpose the structure of these organs has been sufficiently indicated in the previous section. In conclusion, it maybe right to recapitulate the general nature of the ovary or formative organ in its relation to the production of ova. A comparison of the forms previously indicated leads to the general view that the ovary is to be regarded as analogous to the glandular organs. In the great majority of animals highest in the scale, the ovisacs are close fol- licles from which the product of formation (or secretion) escapes by the bursting of the wall of the follicle — in the highest animals, on the external surface of the organ, in those coming next in the series, towards an internal cavity. In other instances, principally among the lower animals, the structure is more ana- logous to that we are accustomed to consider as characteristic of the true glands, in which the secreted cellular product is formed within the same or a continuation of the tubular ducts themselves by which they make their escape. The more complex structure of the capsules in which the large-yolked ovules are produced in birds constitutes a special appa- ratus, which, though without follicular com- plication, may be looked upon as a modifica- tion or higher degree of development of the glandular structure of the ovary, provided for the rapid formation of the larger mass of nutritive substance which is present in these ova. § 4. More detailed description of the ovum of birds as the type of the 1st group. Having in the previous section given a sketch of the general resemblances and dif- ferences observed among the ova of various animals, I now proceed to describe more in detail an example from each of the three groups previously distinguished, and more particularly those of Birds and Mammalia, which demand the greatest share of our atten- tion in the study of development ; and first as to the ovum of the common fowl. Quantity of matter , composition, $c. — The average dimensions of the fowl's egg in this country are the following : The long diameter 2% inches, short diameter If inch. The aver- age weight of eggs of this size is a little more than 2 oz. avoird., or 920 grains.* The extremes in weight which I have ob- served among eggs of the fowl naturally formed are 750 and 1060 grains. Double-yolked eggs are, as might be expected, much larger, reaching often a weight of 1400 grains, or 3^ oz. The yolk weighs about a third of the whole ; the albumen, membrane, and shell forming the remaining two thirds. These parts of the egg are in the following propor- tions to each other in 100 parts ; the albu- * The following is a comparative view of the average size and weight of the eggs of the com- mon fowl, duck, turkey, and goose. Length Breadth (in inches). Fowl - 2-25 1-7 Duck - 2-5 1-75 Turkey 2-7 1-9 Goose - 3-3 2-4 Weight (in grains). 920 nearly 2 oz. 1100 2£ oz. 1300 3 oz. 2600 6 oz. OVUM. til men 58, the yolk 31£, and the shell with its lining membrane, 10£. When eggs are kept exposed, they gradually sustain a small loss, due chiefly to the eva- poration of water, and amounting to about one grain per day. When putrefaction ensues, an additional loss from chemical changes occurs. During incubation, the loss of weight is more considerable, amounting in twenty-one days to 16 or 17 per cent., or nearly one sixth of their entire substance.* The loss by an egg during incubation, therefore, is eight times as great as that which occurs in an egg kept at the usual atmospheric tem- perature for the same period — a circumstance which depends partly on the higher tem- perature, but principally on the evolution of carbon from the oily matters of the incubated egg, in combination with the oxygen of the air, or as carbonic acid, &c. Of the 17 parts per cent, lost during incu- bation, not more than 5£ or 6 consist of water, and the remaining two thirds, that is 10 or 1 1 parts, are derived from the oily and other substances of the egg which undergo chemical changes attendant upon the process of orga- nisation and respiration of the embryo. By evaporation to dryness of the whole egg without the shell and membrane, about 27 per cent, of the substance are left; the oily ingredients of this residue, amounting to about lOf, are almost all contained in the yolk, and the remaining 16i parts of solid matter are nearly equally divided between the yolk and the white. The yolk, therefore, is much richer in the fixed and solid parts than the white ; but its specific gravity, as will afterwards be seen, is considerably reduced by the larger quantity of oily matter it con- tains : the per-centage of solid matter (inde- pendently of the oleaginous substance) con- tained in the yolk and albumen, is in the pro- portion of 32 in the first to 14 in the second.f The solid residue obtained by evaporation of the white at a low temperature, amounting to nearly one seventh of the whole, consists chiefly of albumen ; along with which there is also some animal matter which has hitherto been named by chemists as extractive, and a small amount of salts, which are principally alkaline sulphates, muriates and phosphates, with phosphate of lime, some free soda and sulphur. The yolk contains little more than half its weight of water, or 54 per cent. The remain- ing 46 parts consist of about 17 of albumen, or analogous principles, 28 of oily matter, and 1£ of salts. These last are chiefly alkaline mu- riates and sulphates, phosphate of lime and magnesia, and traces of iron, sulphur, and * See Prout, On the fixed Principles of the Egg, Philos. Trans, and Annals of Philos. for 1822. Also, by the same author, On the Changes of the Egg in Incubation, in the same Journal, for 1823. ; and, Paris, On the Physiology of the Egg, in Linnean Soc. Trans, vol. x. p. 30*4, and Annals of Philos. 1821. j- See Prevost and Morin, in Journ. de Pharmacie for 1846, and Sacc, in the Eggs of the Bantam Fowl, in Annal. des Scien. Nat. for 1847, p. 69. phosphorus. The albumen has an alkaline, the yolk a neutral, reaction.* The membrane lining the shell consists apparently of a protein compound, analogous somewhat to that of the elastic yellow tissue. The shell consists of earthy salts deposited in a delicate matrix of animal matter, which last constitutes not more than 3 per cent, of the whole. The earthy ingredients are in great part carbonate of lime, together with a little carbonate of magnesia, and phosphate of lime and magnesia. Of the ingredients of the egg before men- tioned, the albumen and other animal prin- ciples, together with the sulphur and salts, are no doubt more immediately employed in the growth of the embryo; while the oily matter, besides contributing, as it appears, in some part, to the same purpose, serves more directly and in greater quantity for the re- spiratory process, in which it is consumed largely during incubation. The alkalinity of the white of egg appears to depend on the presence of caustic soda, which albumen has the property of separating from its carbonate. The following tabular view exhibits in a general way the change in the relative pro- portion of the ingredients of the egg resulting from incubation -j- : — Shell and membrane Albumen, &c. - Oily matter, &c. Water - ... J water - 5-6 \ I Oily matt., &c. 11-4 J Fresh Incubated egg. egg. - 10-67 10- - 17-8 19-4 - 18-83 6-5 - 52-7 47-1 17- 100-00 100-00 When an egg is examined immediately on being laid and while yet warm, or still better when taken from the egg-bag of the fowl pre- vious to laying, the yolk and white fill com- pletely the interior; but immediately on cooling, a small space or vacuity appears ge- nerally towards the obtuse end of the egg, and this air-space increases gradually in size as the eggs are longer kept and the natural evapora- tion of water proceeds. This space is formed by the separation of the two principal layers of the lining membrane of the shell. During incubation the air-space increases much more rapidly; and indeed towards the end of this * Composition of the yolk, according to Gobley, in Journal de Pharmacie, 8e. ser. torn. ix. p. 174. Water, about - - - • 53" Vitelline, albumen, and protein com- pounds - 16-5 Oily matters ----- 29- Salts, &c. 1-5 100-0 These salts are the following — viz., chloride of sodium and potassium, sulphate of potassa, muriate of ammonia, phosphates of lime and magnesia, lactic acid, colouring matter, iron, f From Sacc, loc. citat. OVUM. process, and in eggs that have been long kept, the space has extended over the whole width of the egg, and the quantity of gas contained in this space is sufficient to cause the eggs to float in water. The extent of the air-space may be ascertained in some degree by the greater or less feeling of coldness of the shell of the egg near the obtuse end, when it is applied to the skin of a delicate part, such as the eyelid, in consequence of the heat being less rapidly carried off by that part of the shell within which the air-space has been formed, than at others with which the albumen is in contact. Dr. Paris found this air, amounting to about half a cubic inch, to be nearly pure atmo- spheric air, with a small quantity of carbonic acid towards the end of the period of incuba- tion. MM. Baudrimont and St. Ange find it to contain in general more oxygen than atmospheric air, and no carbonic acid j whence they conclude that the shell has a peculiar power of passing outwards the carbonic acid formed during incubation and taking in oxygen.* The formation of the air-space is manifestly a compensation for the loss of sub- stance in whatever way occasioned, that may take place from the egg. We shall have oc- casion afterwards to consider in how far it may be important in connection with the phenomena of incubation. The specific gravity of the whole egg, when newly laid, and before evaporation has taken place, is generally as high as 1090, being raised considerably above the common spe- cific gravity of the fluids and soft parts of animals by the superior density of the shell ; but as the air space increases, the whole spe- cific gravity will be lowered. The specific gravity of the albumen and yolk differ in a considerable degree; that of the yolk , though containing the largest amount of solid matter, being lowest in con- sequence of the large quantity of oily matter belonging to it ; and thus when the albumen becomes more fluid during incubation, the yolk naturally rises towards its upper part, or displaces some of the albumen which lay above it in the newly laid egg. It is also an interesting circumstance, that the specific gravity of the lower and upper parts of the yolk differs perceptibly ; that of the upper part being reduced by the greater quantity of oily matter contained in the cells situated in the vicinity of the cicatricula. The up- turning of the side of the yolk bearing the cicatricula, which is familiarly known, has long excited attention ; and several explana- tions have been suggested of its cause; arid, among others, the chalazae have been supposed to balance the yolk in such a manner as to secure this position. But Von Baer showed that this view was erroneous, and that the less specific gravity of the upper part, or of that portion of the yolk in which the cicatri- cula is placed, is the true cause of the phe- * Recherches Anat. et Physiol. sur PCEuf des Vertebras, Mem. Gouronn. ; published in Mem.des Savans Etrangers smooth outline or margin to the whole cor- puscle. If subjected to pressure, or cautiously ruptured with needle points, they break readily at one or more places, and allow the escape from their interior of the thick granular fluid, which flows slowly out of them in a stream. The granules are in large quantity, as compared with the fluid in which they are suspended, and are most of them of an ex- tremely minute size, probably below an inch in diameter. * See Mutter's Physiology, vol. ii. Although the yolk corpuscles present the distinct external margin now mentioned, and thus constitute capsules containing the gra- nular fluid, yet we cannot, in most instances, detect any vesicular membranous envelope surrounding them. One may sometimes ob- serve a delicate limiting line ; but it has been impossible for me to determine whether it consisted really of a membrane or of a thin condensed layer of the granular substance or plasma containing it. At an earlier period it is probable that these corpuscles have mem- branous envelopes, but when fully formed the greater number are certainly destitute of them ; for occasionally a larger corpuscle may be observed to divide into smaller ones, the outlines of which are nearly as distinct as that of the larger corpuscles. Nor is any nucleus in general to be per- ceived in these corpuscles. I have occasion- ally seen in those from which the granular matter was escaping, and which had thus be- come less opaque than usual, a slight ap- pearance of a clear hyaline circular space, but it scarcely deserved the name of nucleus ; and if these spherical bodies are to be regarded as cells, which 1 think they ought, it must be in a somewhat different acceptation from that in which the term cell has hitherto been gene- rally applied to vesicular organised structures. But recent researches on the early condition of cells seem to have rendered it necessary that we should include under this denomina- tion several simple spherical minute forms of organised or organising matter, which were not at first regarded as true cells by the authors of the cellular view of organic struc- ture ; and when we consider the mode of their formation, it is more than probable that the vitelline corpuscles now under consideration may be included among the number.* They probably constitute, at all events, as Schwann has first shown, one stage of deve- lopment of a cellular structure ; and, in the meantime, they may with propriety be styled the larger granular yolk corpuscles. There is considerable uniformity in the ap- pearance and structure of these corpuscles in nearly the whole of the deeper-coloured por- tion of the yolk ; but immediately below the vitelline membrane, several layers of them are of a smaller size, and the outermost layer of all consists of cells which are much smaller and more compressed, distinctly nucleated and of a short cylindrical or prismatic shape. In some places also, corresponding to the con- centric lighter lines which run through the yellow yolk, some approach is seen to the next kind of yolk cells or corpuscles, which I shall have to describe — viz., those of the cavity. The substance of the yolk-cavity and canal, which in the unboiled egg may be distin- guished from the other part by its lighter * The above observation has a general application to such minute spherical masses of matter as are destitute of external envelope or nucleus: but in reference to the corpuscles of the yolk, I ought to observe that Schwann regarded them as cells in various stages of growth. OVUM. 73 colour, and in the boiled egg by its softer consistence and less granular appearance, is found by microscopic examination to consist of organised corpuscles floating in a larger portion of fluid, and different (from those of the external part of the yolk. The transition from the one kind of corpuscles to the other in these two portions of the yolk, is not sudden ; but many gradations of intermediate forms are to be met with on the confines of the two regions. In the central part of the cavity or latebra, which, when boiled, appears like a thick milky fluid, corpuscles very different from those of the external part are to be found (see Jig. 52, c). They are almost all of a very regular spherical form with a delicate and clear, but distinct vesicular wall ; the interior of the vesicle is occupied by a perfectly limpid fluid, and by one or several highly refracting globules of various sizes, not exactly similar to nuclei, but rather like oil globules, floating within the cell and moving with freedom from one part of it to another. The diameter of the clear vesicles varies from T£^ to ffa of an inch, the •most being about -^^ ; therefore about half the size of the granular corpuscles of the yellow yolk. The internal oil globules are of very various sizes, the largest being generally about a third or a fourth of the diameter of the enclosing vesicle. Mingled with these vesicles, there are also floating in the fluid of the yolk cavity in considerable numbers, but in less quantity than the vesicles them- selves, a set of simple highly refracting globules, exactly similar to those contained within the vesicles from which we may sup- pose they have been set free. These oil-like globules are of every variety of size, from the minutest point up to y^. or TT^ of an inch. Towards the surface of the yolk cavity and canal, and extending below the cicatricula, where the vitelline substance gradually passes into the darker yellow yolk, the microscope shows some mixture of and transitions be- tween the several cells or corpuscles before described, those of the intermediate structure being in greatest numbers ; these exhibit very various gradations of deposit within them, from the finest granular particles in some, to larger and fewer oil-like globules in others. In most of these transition corpuscles a delicate vesicular wall is perceptible. In the more ad- vanced of these transition forms, as the minute granules are in the process of uniting into larger and larger oil globules, and at last coa- lesce into a very few or into a single one, the condensation of the exterior layer increases to form a vesicular wall, and a separation of an albuminous fluid from the oil globules takes place within (see^g. 52, B). It is these vesi- cular globules of the cavity which, according to Reichert, are the more immediate source of additions to the germinal membrane in the course of development ; for the cavity and canal expand, as it were, at the expense of the yellow yolk, and as these inner globules increase the extension of the haloes and change of colour of the yolk in the first days of incubation spreads rapidly over its surface below the germinal vesicle. 3. Cicatricula or proligerous disc. — There does not appear to be any marked difference as to the minute structure of the mass of the yolk and its cavity in the newly laid egg and in the mature ovarian ovulum ; but the cica- tricula undergoes a great change during the. passage of the ovum through the oviduct, which is indicated in a marked manner by the difference in its microscopic structure. During this period, besides the loss of the germinal vesicle, the cicatricula has undergone the peculiar process of segmentation and cell formation, upon the details of which it is my intention to return in connection with the special history of that process in the ovum of mammalia, batrachia, and other animals. The cicatricula of the laid egg is, in fact, after having undergone this process, the organised blastoderm or germinal membrane in which, under the influence of the heat of incubation, the rudiments of the embryo take their origin. It already consists, before incubation, of two layers]of organised cells, which'are the indica- tion or earliest condition of the upper or serous, and lower or mucous layers, which were de- scribed by Pander and Von Baer as taking their origin only after incubation for some hours.* fSee/g. 52, D.) The cells of the upper layer are about Ty>Tny of an inch in diameter. They are closely set and very slightly connected together in a continuous layer one cell thick, presenting a smoother upper surface next the vitelline membrane. Each cell consists of an external vesicular wall, a distinct nucleus, and some granular deposit. The nucleus is highly re- fracting. The cells of the lower layer are nearly double the size of the upper ones, more regularly spherical and less closely connected together. They do not in general present any single nucleus, but rather a small mass of granules and oil-like spherules within them, giving them much of the appearance, though smaller in size, of the corpuscles found be- tween the cavity and rest of the yolk. In the cicatricula or proligerous disc of the ovarian yolk, on the other hand, containing the germinal vesicle set in its centre, the microscope shows no truly organised cells, but only a mass of simple spherules of very various sizes, but the largest of which for the most part are less than half the diameter of the cells in the upper layer of the blas- toderm of the laid egg. They are without any nucleus, and have all the appearance of simple solid spherules from ^- to ^(jW of an inch in diameter, of considerable refracting power, and, indeed, very similar to the nuclei of the cells in the upper blastodermic layer. Vitelline membrane. — The condensed layer of structureless membrane which has gene- * The most exact descriptions of the minute structure of the cicatricula are those of Schwann in his Microscopic Researches ; of Reichert, in his Beitrage zur heutige Entwickelungsgeschichte, &c. ; and Remak, in his BeitrSge zur Entwick. des HUhnchens, &c., 1850. 74, OVUM. rally received this name in the fowl's egg, and which I have hitherto regarded as corre- sponding with the immediate membranous in- vestment of the yolk (zona pellucida) in mammalia, and in all animals, constitutes, both in the mature ovarian yolk and in the laid egg, an entire thin transparent covering of the yolk substance, without any aperture that has been discovered in it at any time ; delicate and easily torn, but yet of such con- sistence that under water any portion of it may easily be removed and examined. In the egg which has passed through the oviduct, the vi- telline membrane floats free from the cicatri- cula and surface of the yolk substance ; but, so long as it remains in the ovarian capsule, these parts cohere somewhat together j so that, in general, on removing a part of the yolk membrane, a more or less complete lining of the nucleated or outermost layer of yolk cells comes away with it. The microscopic exami- nation of this membrane in the fully formed yolk does not, as already stated, show any very distinct structure beyond an obscure fi- brillar and molecular marking, of such fineness, indeed, as to require a high magnifying power (500 to 600 diameters) to bring it into view ; and in many parts the membrane appears per- fectly homogeneous. In the earlier stages of the yolk's growth, however, we shall see that this membrane is not to be distinguished from the layer of closely set nucleated cells, the outer- most part of which appears to become fused together into the membrane as the yolks ad- vance to maturity (see fig. 53, K vm). We shall presently see that the vesicular envelope which is generally termed the yolk membrane in the bird's egg, and in the ova of all animals pos- sessing the large yolks, is probably a different structure from the perfectly homogeneous ve- sicle which in many other animals arises at a much earlier period of the growth of the ovule, and remains in them as the external covering of the yolk to the end. Early condition and first formation of the ovarian ovum in birds. — It has already been stated that the ovula exist at a very early period of life in the female bird ; constituting in their earliest undeveloped condition minute cells closely surrounded by the simple vesi- cular capsules and the solid substance of the ovary, which at [this period has not lost its primitive compact form. As the bird ap- proaches maturity, a considerable number of the ovula situated nearest the surface in- creasing in size make an advance in their structure by undergoing certain changes which will immediately be more particularly adverted to. Having attained various sizes from •£$ to -£ of an inch, they project slightly as rounded bodies from the surface of the ovary, and remain in this condition till the approach of the breeding season, when some of them destined to reach their full state of develop- ment, are at last discharged from their ovarian capsules. A much greater number, however, must remain in the undeveloped condition, awaiting future seasons of evolution ; and a very considerable proportion of the whole germs of the ovary rather pass through a retrograde process and gradually disappear without having attained to any considerable size. Of the smaller or undeveloped ova, such as those of less than ^ of an inch in dia- meter, some are of a dull whitish or milky colour, the deeper-coloured external yolk substance not having been yet formed, and the yolk substance consisting almost entirely of small spherules or globules, not of true cells or of the granular corpuscles which appear at a later stage. Those between -^ and £ of an inch are for the most part of a lighter yellow than the larger ovula ; but above the latter size the colour has attained nearly its full in- tensity from the deposit externally of the deep-coloured yolk substance. In all the ovula above -J^ of an inch it is easy to see the germinal vesicle situated on the surface of the yolk, when the capsule is opened, embedded in a more opaque and compact layer of substance which repre- sents the discus proligerus, extending at this period nearly over the whole surface of the yolk. But in those less than ^ or ^ of an inch, the vesicle is not to be seen on the surface. On carefully opening or breaking up the substance of the yolk, the vesicle is easily found in the softer internal substance which flows out from the centre. From the central part of the small ovule, the vesicle appears gradually to pass outwards towards a deter- minate part of the surface, making its way through the proligerous layer or primitive yolk granules ; and thus, in examining ovula at this stage, I have been able to perceive occasionally that the vesicle was situated ,in a more or less deep depression on the inner surface of that layer, which therefore must be perforated, as it were, by the vesicle in its passage towards the surface. The sub- stance of the disc afterwards collects round the vesicle internally, and is accumulated in greater quantity (cumulus) in that situation. This change of place of the germinal vesicle from the centre or interior to the surface of the yolk in the progress of development of the ovula occurs in some degree throughout the animal kingdom ; but it is especially re- markable in the eggs of birds and other animals with large yolks, in consequence of the peculiar connection of the vesicle with the proligerous disc. In the batrachia also, the change is very obvious, and the progress of the vesicle outwards has been well described by Von Baer and others. In this latter class of animals the proligerous layer covers a much greater part, or indeed in most of them nearly the whole of the yolk ; but the germinal vesicle occupies always a determinate place in the centre of the layer ; showing that the development of the various parts of the ovum proceeds from the first with a fixed relation of position between the germinal ve- sicle and other parts. In birds, as in all other animals, the ger- minal vesicle, which we shall see is the fun- damental part of the ovum, is proportion- ally large in the earlier stage of growth of the ovule, being at the first from a fourth to a OVUM. 75 half of the diameter of the whole ovule. In the progress of growth, it enlarges some- what, but only in the earlier periods, and in less proportion than the yolk, and undergoes no farther increase during the greater part of the time that the yolk acquires the greatest addition of new matter. It is worthy of remark, however, that the germinal vesicle is originally of a large size in the eggs of birds and other Jarge-yolked ova ; that it is also of very considerable size, even proportionally larger, in the batrachia ; and that in mammalia, and other animals with the smaller and gra- nular yolk, its size bears in general a propor- tion to that of the yolk. The substance of the yolk appears, in the first place, to be simply granular, or to be composed entirely of minute molecules such as those which always form the yolk in mam- malia. These are united together by a some- what glairy fluid ; larger spherules gradually appear among them ; and next the distinction between the substance of the proligerous disc and of the yolk cavity becomes apparent. Lastly, rthe deep-coloured yolk corpuscles are produced, layer after layer being deposited from the exterior, so that the outermost are the last formed. Externally a closer-set layer of nucleated cells covers the surface, in con- nection with which the vitelline membrane is formed. The vitelline membrane is not formed at an early period in the bird's egg : it cannot indeed be perceived in ovula of a tenth of an inch in diameter. We shall presently see that its relations and mode of formation are peculiar in the bird's egg. Morphology of the bird's egg as ascertained from its first origin and development. — The ovaries of the common fowl, and indeed of most large birds, are less favourable for the investigation of the first origin and earliest condition of the ovule, than those of the smaller tribes j this arises, not so much from the dense structure of the ovary in the undeveloped state, as from the great opa- city produced in the ovules themselves, almost from the first, by the deposit of thick-set yolk granules. In some of the smaller singing birds, the thrush, yellow-hammer, or chaf- finch, the parts are clearer and more trans- parent ; and it will be found that the pheno- mena of earliest formation are most easily investigated in them. According to Dr. Martin Barry's observa- tions, in birds as well as in other animals, the germinal vesicle is the part of the ovum which is first formed. In the pigeon and common fowl, he has observed these vesicles in the ova- rian substance at a very early period*; and he believes their origin as simple cells to precede that of the ovarian vesicles, or follicles, or, as he has termed them, ovisacs, which surround them at a somewhat later period, but still in the earliest stages of the formative process. By other observers the ovarian vesicles have * See Philos. Trans, for 1838, p. 309. In this, coinciding with the opinion previously expressed by Von Baer. Fig. 53. Earliest stages of the formation of the ovarian egg in the Bird. A, B, c, D, E, F, actual representations of portions of the ovarian stroma and ovisacs of the thrush ; G, H, i, K, diagrammatic sections of the same. A. In the ovarian stroma are seen the earliest state of the ova and ovisacs that can be perceived, consisting, first, of minute granular spots ; next, of clear points within a minute granular mass ; and third, of small germinal vesicles, surrounded with the minutely granular dark yolk substance. Compare with G, in the diagrammatic figure. B and c. Different stages of formation of the ovi- sac round the small ova : the epithelium is seen to line the sac : the germinal vesicle with occasionally a single macula is now apparent. D. The epithe- lium of the ovisac shown in focus over the whole surface : in the other figures it is only shown in 76 OVUM. focus at the margin. E. The ovisac and ovum more advanced ; o, v, ovisac, with epithelial lining ; v, minutely granular yolk ; g, germinal vesicle. F. Part of an ovule of £ of an inch in diameter highly magnified : v, minutely granular or primi- tive yolk substance ; g, germinal vesicle ; 2, thick consolidated membranous layer which formed a ve- sicular covering for the primitive ovule, and which corresponds to the zona pellucida of the mammi- ferous ovule. i and K are intended to illustrate, diagrammati- cally, the view, that after the disappearance of the zona, and the formation of larger granular yolk cells, the outer layer of the cells of this substance forms the permanent vitelline membrane of the bird's egg ; v, d, remains of minutely granular yolk, form- ing the vitelline disc round the germinal vesicle ; s, g, large corpuscles of the yolk ; v, m, outer layer of the cells of the same, on which the vitelline mem- brane is afterwards formed. been looked upon as the primitive or first- formed structures connected with the origin of the ova, the germinal vesicles subsequently making their appearance within them. We shall return to this point hereafter in con- nection with the history of the mammiferous ovum. My own observations agree with those of Barry, as I have sometimes observed very small germ-vesicles or cells in the ova- rian stroma without any follicular covering. But it must be admitted, at the same time, that in birds the ovisac or ovarian vesicle is formed so early that it is observed almost always coexisting with the germinal vesicle or rudiments of the ovule ; so that, if the latter takes the precedence of the ovisac, it must be by a very short period. According to Barry, there is seen almost from the first, in the clear germinal vesicle, a minute distinct granule or round spot, which constitutes the first state of the macula germi- nativa. Very soon the vesicle is surrounded by a small quantity of a clear fluid in which are rapidly deposited globules or granules constituting the first rudiments of yolk substance. There is no vitelline membrane, however, in birds, at the first ; nor are the larger cells which at a later period inter- vene between the ovisac and the primitive yolk, formed in the earliest stage. The smallest ovisacs which Barry observed, and which con- sisted of perfectly simple vesicular linings of the cavities containing the rudimentary ova, in the pigeon and common fowl, were from ^^ to ^-3- of an inch in diameter.* At a somewhat later period, the number of maculae (nuclei) in the vesicle, and of the yolk granules externally, had increased, and a delicate membrane, which he describes as vitelline membrane, and believed apparently to be the same which afterwards surrounds] the large yolk in the fully-developed ovum, has made its appearance. At this period also * Vide loc. cit. Plate v., figs. 18, 19, and 22 of pigeon ; figs. 23 and 24 of common fowl. The mem- brane which Barry described as vitelline in the earliest stages of growth of the bird's egg was pro- bably not so, but the outline merely of the albumi- nous substance in which the primitive yolk granules are deposited. This will be made more apparent in our description of the formation of the ova of Batracbja. there begin to be formed within the ovisac a set" of larger nucleated corpuscles or cells, which are external to the true ovum, and which may be considered as corresponding with the so-called granular contents (sub- stantia and tunica granulosa) of the Graafian follicle in mammalia. The early structure and development of the ovum of birds have more recently been described, with considerable detail, from ob- servations on the chaffinch and common fowl by Dr. H. Meckel*,; and as the observations of this author have led him to take a somewhat different view of the relations of some of the parts of the ova of birds and other animals from that which has hitherto been generally adopted, it will be proper to give a particular account of them in this place. Many phy- siologists have felt the incongruity of the comparison generally made between the mi- nute and simple ovum of the mammifer, and the large and more complex yolk of the bird, and most are disposed to acknowledge the necessity of making some more marked distinction between the granular and the cellular yolk substance in the two great groups to which these ova respectively be- long. It has before been stated, that Von Baer on his discovery of the mammiferous ovum, regarded it as corresponding, not to the whole ovum of birds, but to the vesicle of Pur- kinje. The discovery, in 1834, of the germinal vesicle in the mammiferous ovum, of the ex- istence of which Von Baer had no distinct knowledge, induced Valentin and others to maintain that the essential parts of the ovum are the same in the bird and the mammifer. But it may be doubted whether physiologists may not have proceeded further than they were warranted by observation in regarding the vitelline membrane and large corpuscles of the yellow yolk of birds as essentially corre- sponding parts with the zona pellucida and the smaller granular yolk of the mammifer. For the membrana vitelli of the bird's egg may, perhaps, be more analogous to the outer- most layer of the membrana granulosa of the Graafian follicle, and the large cellular yolk to a part of the same substance or the fluid of the Graafian follicle ; while the minutely gra- nular yolk in which the cicatricula originates and the germinal vesicle together are the true representatives of the small ovum of the mam- mifer. It seems undoubted, that what we term the yolk membrane in the fowl's egg does not exist in the early stages, and is formed indeed only as the ovarian egg approaches maturity, and it is admitted that no large cells similar to those of the bird's yolk exist within the cavity of the zona pellucida of the mammi- ferous ovum. If this view is correct, we may expect to find a representative in the egg of the bird and of other animals having similar ova, of the very marked enclosing vesicle, which has received the name of zona pellucida * See his paper, Die Bildung der fur partielle Fiirchung bestimmten Eier der Vogel, &c., in Sie- bold and Kolliker's Zeitsch. fur Wissenschaft. Zool. vol. lii. p. 420, 1«52. OVUM. 77 in the mammiferous ovum. Now, according to H. Meckel there is, not from the very first, but in the earlier stages of formation of the yolk of the fowl and of other birds, a homo- geneous vesicular membrane enclosing the primitive or granular yolk, or what he terms the true egg substance. As the cellular yolk is formed, this membrane, to which he thinks himself warranted in giving the name of zona pellucida, disappears, and already in ova above J, the two layers of the ovisac ; m g, membrana granulosa, near which is the discus granulosus, with the ovum imbedded. [82] OVUM. but in some animals, in which the vesicles are proportionately more expanded, they extend beyond the general line of the surface in various places, and even sometimes give the ovary somewhat of the mammillated or grape- like appearance more common among ovipa- rous animals. The follicle is filled to distension with a clear albuminous fluid, which escapes with force when an incision is made through the Fig. 55*. Ovarian ovum of the Dog. (From Bischoff.} a, magnified representation of the ovarian ovum of the dog, nearly mature, situated in the discus proligerus and part of the cells of the granular membrane ; b, several detached granular cells. d, another ovarian ovum of the same animal perfectly ripe, immediately previous to the rupture of the Graafian follicle ; the cells of the proligerous disc have become of a pediculated shape ; e, some of these cells detached. e, the ovum from the same specimen as in fig. a, freed artificially from the granular cells of the disc, showing externally the thick clear zona or external membrane, and internally the opaque 3rolk substance : in the latter the germinal vesicle is obscured by the opacity of the substance sur- rounding it. /, the same ovum burst by pressure, showing the contents of the ovum which have escaped, viz. the finely granular yolk substance and the germinal vesicle with its macula. membrane. Close to the inner surface of the follicle, and surrounding the fluid, is situated the layer of nucleated granular cells which has been termed tunica or membrana granulosa, from the opaque granular appearance of the cells composing it. These cells form a com- plete vesicular lining of the follicle; but throughout the greater part they cohere with only a moderate degree of firmness, so that the membrane readily tears when the follicle is opened. The minute ovum is imbedded in a thicker portion of this layer, the cumulus or dis- cus proligerus of Von Baer, and is almost in- variably situated close to the inner surface of the most projecting part of the Graafian follicle (see fig. 54*. A. and c., mg.) where in some animals, but not in the human ovary, the ovum may be detected in the undissected fol- licle through its coats and the ovarian cover- ings. The cells of the membrana granulosa are in general about -^Vu" in diameter. They adhere with considerable firmness to the surface of the zona ; so that when the follicle is opened and its contents are allowed to run upon a plate of glass for examination, the ovum is always found placed in its disc in a circum- scribed attached portion of the membrana granulosa of about twice its own diameter. The ovum is itself of a nearly perfect sphe- rical form when freed from pressure ; but as it lies thus imbedded in the membrana granulosa, and moistened on a plate of glass, it gives rise to a slight rounded elevation in that membrane, which may easily be detected with the naked eye when the specimen is viewed sideways. When the contents of the Graafian follicle are discharged naturally during life, a small aperture occurs nearly in the centre of the most projecting part of the wall of the follicle ; and as the ovum lies near this place in the membrana granulosa, it is liable to be evacuated first, along with a portion of that membrane, which is soon torn away from the rest by the pressure of the fluid behind it, impelled by the contraction of the walls of the follicle and surrounding ovarian substance. During the descent of the ovum through the Fallopian tube the cells of the proligerous disc immediately surrounding the ovum alter their form, and are subsequently detached from the zona, so as to leave its external surface quite free and smooth. I have not, any more than Bischoff, been able to observe the four retaining straps or retinacula described by Martin Barry in his first series of Researches, as portions of the membrana granulosa na- turally thicker than the rest, and which, radiating nearly at right angles from the pro- ligerous disc, serve, as it were, to guide the ovum and its disc towards the aperture by which it escapes on the bursting of the fol- licle. The accompanying figure from Coste (56*.) gives that author's view of a structure somewhat similar to the retinacula of Barry. The size of the mammiferous ovum itself is much more uniform among the different families of Mammalia than that of the Graafian follicle, OVUM. [83] Fig. 56*. Ovum, of the Rabbit in the tunica granulosa. (.From Coste.) The middle part of one of M. Coste's figures has been here copied to show the peculiar arrangement of the granular cells round the disc and ovum, which according to him are of the same nature with those described by Dr. Martin Barry as retinacula. It may be doubtful whether this structure is constant. and bears no regular proportion in different families of animals to the stature of the whole body. In the mature state this variation ex- tends from T£o to 2^0 or g-i^ ". The following are the results of a few measurements made by myself and others of the external diameter of the mature ovarian ovum, viz., man T-|^, dog o, cat yi^, rabbit T^, rat ^, mouse Pig ^o> cow ?in, guinea-pig ^".^ The external tunic, or zona pellucida (a term founded on the description of Von Baer*, from its presenting the appearance of a transparent ring between the opaque granular yolk-mass within and the granular cells externally), is of great proportional thickness ; viz., from T-gW to 2sW/r> or from i to T\ of the whole diameter of the ovum. When entirely freed from the granular cells, its external surface appears smooth ; and the inner surface, which is exactly parallel to the outer, is also re- markably smooth. The substance of this tunic is very tough, and possesses considerable elasticity ; so that the ovum and its zona may be flattened by external pressure to a great extent ; and yet it regains its nearly spherical form when the pressure is removed. It is of glassy transparency and homogeneous ; neither any laminated, nor fibrous, nor other structure being perceptible under the highest magnify- ing power. It is easy to obtain evidence that it is one thick membrane, and not composed of two layers with intervening fluid, as some have held, by cleaving it with fine needle- points, when the cut edge becomes fully ap- * Epistola de Ovi Mammalium et Hominis genesi, Lipsiae, 1827. parent. It has recently been stated by Remak*, that in the mature ovarian ovum of the rabbit, when freed from the granular cells, radiated lines may be perceived running quite through the zona pellucida ; these linear radiations, he conceives, indicate a peculiar structure of the zona, somewhat similar to the perforated con- dition of the outer membrane of the ovum in osseous fishes. I have perceived some of this radiated appearance ; but I am inclined to be- lieve that it depends not on any structure of the zona itself, but rather on the marking produced by the adhesion of parts of the cells of the tunica granulosa, which become pedi- culated in very ripe ova, and have then a ra- diated appearance on the zona under pres- sure ; as represented by Bischoff in his view of the ovum of the dog, of which fig. 55 D. is a copy. I shall have occasion afterwards to state the nature of the fine canals which have been observed in the outer tunic of fishes' eggs. It has been customary among ovologists, till very recently, to look upon the zona as corresponding to the external membrane of the yolk in the bird's egg. But from what has been already said in connection with that subject, the propriety of draw- ing a distinction between these two enve- lopes has been fully shown. I prefer, there- fore, to retain the name of zona pellucida, though it may not be perhaps the best de- signation, as it prevents all confusion which might be introduced by views of its analogies. It will hereafter be more fully demonstrated that it not only differs in its mode of origin from the true vitelline membrane of birds, but that it also has a different destination in connection with embryonic development, in- asmuch as, though formed in the ovary, it remains and constitutes the basis of, or be- comes incorporated with, the important struc- ture which at a later period becomes the chorion. In the foregoing description of the mem- brane of the mammiferous ovum, I have adopted the view first advocated by Coste-j-, and by Thomas Wharton Jones J ; and more fully brought out and established by the re- searches of Bischoff in his admirable works on the development of the Rabbit and the Dog. § It may be proper to remark farther, that though the name of zona pellucida has been employed to designate the thick single tough membrane by which, as is now well ascertained, the yolk of the mammiferous ovum is invariably enclosed from an early period of its formation in the ovary, this term is used synonymously with that of vitelline membrane, and as applied to * Muller's Archiv. &c. for 1854, p. 252. f Recherches sur la Ge'ne'ration des Mammiferes, 4to. Paris, 1834, fig. 2.; and Embryoge'nie Com- pared, torn. i. p. 200, Paris, 1837. I In a paper read to the Royal Society of London in 1835 ; printed in the London Medical Gazette for 1838, p. 680. § Entwickelungsgeschichte des Kanincheneies, Braunschweig, 4to. 1842 ; and Entwickelungsg. des Hundeies, Braunschweig, 4to. 1845. [G 2] [84] OVUM. the only covering with which the ovarian ovum is provided at the time of its leaving the Graa- fian vesicle, excepting that which it retains for a time derived from the cells of the tunica granulosa in the proligerous disc. Von Baer indeed, from whose description the term pellu- cid area or zone has been borrowed, was not fully aware of its consisting only of one thick membrane ; and more than once, both in the Epistola and in the Commentary upon it, expresses himself doubtfully as to whether this pellucid space or halo* might not be formed of an external envelope which he terms the cortical membrane, and of another situated within it. It is well known that when the mammi- ferous ovum has been fecundated, and arrives in the cavity of the uterus, and begins then rapidly to expand, it is covered by a mem- brane which soon undergoes great extension, and acquires a villous structure on its external surface, by which it may always be easily re- cognised. This villous envelope of the ute- rine ovum, universally now known as the chorion, is the product no doubt of changes which only occur in their completeness after fecundation, and as an accompaniment of embryonic development ; but still as it ap- pears probable that the zona pellucida is in- timately connected with the first condition of the chorion, and as the first formation of the latter membrane is by many believed to take place independently of fecundation or fcetal development, it is necessary for me to make some remarks in this place on the relations of the zona pellucida to the external cover- ing which the ovum obtains in the first periods of its residence within the female passages. This is a subject on which embryological writers are by no means agreed, and several of them indeed have themselves changed their opinions in regard to it in the progress of their researches. Von Baer, the correctness of whose general views on the phenomena of development we have occasion to admire in almost every part of the subject of which he has treated, was at first of opinion that the chorion might arise in Mammalia from the outer of the two layers of which he at that time (though also doubt- ingly) conceived the external covering of the ovarian ovum to consist, and he looked upon this as a great difference or departure from analogy between the bird's egg and the ovum of the mammifer : but in his work on Deve- lopment -j-, published eight years later than the Epistoia and Commentary, he states his convic- tion from his observations, that in some mam- miferous animals at least, such as the pig and sheep, the chorion is formed by external de- posit on the surface of the ovarian ovum du- ring its descent into the uterus, and therefore takes its origin more in analogy with the ex- * Spatium pellucidum, halo vel peripheria lu- cida. See Commentary on the Epistola, as trans- lated by Breschet in his Repertoire, 1828, p. 52. t Beobachtung. und Reflexion, liber Entwicke- lungsgescb. &e., Konigsberg, 1837, part ii. p. 185. ternal covering of the bird's egg. At the same time he confesses that he was not able to reconcile this view with what he had seen in the dog and rabbit. Valentin, in his Manual of the History of Development*, regarded it as most probable that the chorion is formed by the deposition and consolidation of an albuminous matter on the surface of the ovum during its descent through the first part of the Fallopian tubes; but though taking, as it appears, a perfectly correct view of this subject, he did not bring forward observations sufficient to establish the opinion which he had founded chiefly on analogical considerations. We owe to Thomas Wharton Jones the first direct observation of the actual deposit of a layer of albuminous matter round the surface of the zona pellucida. But although Mr. Jones, in the observation which he made on the ovum of the rabbit within the Fallopian tubes on the third day after conception, was quite assured that a new structure had made its appearance in considerable thickness on the surface of the zona, yet he at first sup- posed that this might proceed from some change in the remains of the granular tunic which adhered to that membrane after it had left the Graafian follicle.f He afterwards, however, became aware of the source of this fallacy, and adopted the view that the mam- miferous ovum receives a superadded struc- ture, contributing to the formation of the chorion, in its descent through the tubes. In the first series of his Embryological Re- searches, Martin Barry described not only the zona pellucida as recognised by other ob- servers, but also a distinct vitelline membrane within it; and he conceived that the zona became afterwards the chorion. But in his second series he became aware, both from the statements of Wharton Jones and from his own observations, that a new deposit occurs in the rabbit's ovurn ; and this new deposit he now regarded as " the true chorion." He retained, however, for a time his view of the separate existence of a vitelline membrane ; and thus described articulately three mem- branes as belonging to the mammiferous ovum, viz., vitelline membrane, zona pellucida, and chorion. J The first membrane he believed to disappear previous to the period of full ma- turity : the two last he regarded as together the source of the chorion of a later stage. Bischoff also had not been aware from his earliest observations that any new deposit occurred round the ovum of the rabbit in the tubes; and even after he had become ac- quainted with this fact, and had observed it himself, as he did not detect a similar deposit on the ovum of the dog, he adhered to the * Handbuch der Entwick. &c. des Menschen, Berlin, 1835, pp. 38, 39. t On the First Changes in the Ova of the Mam- mifera, in consequence of Impregnation, and on the Mode of Origin of the Chorion, in Phil. Trana. 1837, part. ii. p. 339. I See Phil. Trans, for 1839, p. 316. OVUM. [85] view which he had previously taken, that the zona becomes the chorion, or at least that a new deposit is not in all Mammalia necessary for the formation of that membrane. Fig. 57*. Fig. 58*. Ova of the Rabbit from the Fallopian tube three days after impregnation. A, shows on a dark ground one of these ova, of which B is an explanatory outline, y, s, are the yolk segments of which there were eight; z, the zona ; a, the thick layer of albumen which in this animal is always deposited on the exterior of the zona after the granular cells have been removed from it. c and D. Other ova from the same animal ; in D, are shown three projections of the albuminous covering which have been taken for villi of the chorion ; but which according to Bischoff are not so. This ovum was farthest clown in the Fallopian tube. In a series of observations made by myself on the ovum of the dog and rabbit during their descent from the ovary to the uterus, in the summer of 1840, I was induced to adopt the opinion that a new deposit does really occur on the surface of the ovum in both of these animals. I repeatedly ob- served the large gelatinous or firm thick albuminous covering on the rabbit's ovum when it had just entered the cavity of the uterus ; and in several instances 1 thought I could perceive the first formation of the villi of the chorion by sprouting or budding from the surface of the newly deposited sub- stance, which, as in Wharton Jones' and Barry's observations, it was quite easy to dis- tinguish from the membrane of the zona. In the ovum of the dog I admit, with Bischoff, the appearance is very different ; but yet my observations appeared to me to demonstrate that in that animal also a substance is super- added to the surface of the zona, for that mem- brane, which presents at an earlier period a Ovum of the Dog from the Fallopian tube ten days after impregnation. A. The yolk has undergone division into eight segments, and there is a thin irregular deposit of albumen on the outer surface of the zona. (This is represent* d too light in the figure.) B. Explanatory outline of the same ; y, s, yolk segments ; z, zona pellucida ; a, layer of albumen, from which in connection Avith the zona the chorion takes its origin. perfectly distinct and smooth outline on its ex- ternal surface, becomes in the course of the descent through the Fallopian tubes and by the time of its first arrival in the uterus, not only irregularly flocculent on its surface, but also thickened ; in fact, presents all the appearance of a granulo-mucous substance having been deposited upon it. It may be proper to explain here, that it has now been fully shown by Bischoff's excellent observations, that in both the animals men- tioned, and also in the guinea-pig, the cells of the tunica granulosa, which adhere to the surface of the zona when it leaves the Graafian follicle,are completely separated from it within the first two or three days of the residence of the ovum within the tube, so as to leave the external surface of the zona perfectly smooth. Bischoff has shown, indeed, as I have also repeatedly observed, that a change has oc- curred in the cells of the proligerous disc, adherent to the ovum while it is still within the ovary, which indicates its approaching maturity. This change consists, as already stated, in these cells becoming somewhat spindle-shaped or pyriform, their narrow or pointed ends being attached to and radiating from the surface of the zona. (See as before fg. 55. D.) It is quite easy, therefore, after this separation takes place, to distinguish any change by addition of new matter or otherwise which the surface of the zona may undergo. No one can fail to perceive the [o 3] [86] OVUM. addition to the ovum of the rabbit, the diame- ter of which is thus increased between two and three times, so as to give it somewhat the aspect of the ovum of a Batrachian in minia- ture ; and in the dog it has appeared to me that the increased thickness and more opaque and flocculent roughness of the surface of the zona were sufficient proofs of a new deposit having taken place. This deposit, no doubt, becomes very completely incorporated with the substance of the zona, and is not easily to be distinguished from it ; but in one or two instances I have thought that I was able to perceive a line of demarcation between them. Several of Bischoff 's very faithful figures seem to me even to represent this deposit as it has occurred on the ova of the dog. But his statements in his work on the Development of the Guinea- Pig * are so precise against the occurrence of such a deposit, that further ob- servations will be required fully to determine the question whether it is of constant oc- currence or essential to the formation of the chorion. Later observations lead me to think that I may have been in error in supposing that the villi of the chorion grow directly from the al- buminous deposit. These villi, which, as I have said, form a most characteristic feature of the external covering of the mammiferous ovum in the course of development, begin to be formed only when the ovum has reached the cavity of the uterus. The time of the formation of these villi, as well as their size, varies, however, con- siderably in different animals, and probably also to some extent in the same animal, -j- They are developed from the external surface, and their structure is at first nearly homo- geneous, or at least only slightly granular ; they afterwards acquire a cellular structure, and in the course of foetal development be- come at an early period the seat of a compli- cated vascular growth, by which the relations of the maternal parent and offspring are main- tained through utero-gestation. But the fuller description of this part of the growth of the chorion belongs rather to the history of de- velopment after fecundation. My present object has been only to show the relation of this membrane to the zona or ovarian cover- ings of the ovum. The contents of the ovum or parts within the zona consist of the yolk-mass or yolk- substance, and the germinal vesicle. The first of these constitutes a spherical mass of varia- ble consistence, in which granules, or molecules and globules of various sizes, from the most minute up to about ^^0 or 7oW> are sus- pended in a fluid. The proportion of the gra- nules to the fluid varies to a considerable ex- tent in different animals, the ovum being much more opaque, and usually of a dull-yellow co- lour when the granules are in large quantity, as is the case in most Carnivora, and may be easily seen in the dog or cat. The clear fluid in * Entwickelungsg. des Meerschweinchens, 4to. Giessen, 1852. t Barry and Bischoff. Fig. 59*. Ovarian ovum of the Rabbit. (From Coste.} a, ovarian ovum extracted from a nearly ripe Graafian follicle, and freed from the adherent granular cells ; the close set granules of the yolk substance, among which the germinal vesicle is perceived with a slightly oval macula or nucleus, are well represented. b, the same burst by pressure ; the yolk granules adhering together by a viscid clearer fluid sub- stance are seen escaping from the large aperture in the zona along with the germinal vesicle. which the granules are suspended varies also in its consistence, being of a marked viscid qua- lity in some instances, and thin and limpid in others; so that in some animals, when the zona is punctured, the yolk-substance flows freely out, while in others, and this is the case in the human ovum, the yolk-substance holds together as one consistent mass. The yolk- substance does not adhere in the slightest to the interior of the the zona, but on the con- trary is readily detached from it ; and in some instances, in the entire unimpregnated ovum, a space is seen between the yolk-substance and the zona, formed apparently by the imbibition of water between them. This separation be- tween the yolk-substance and zona appears to be, at a later period, a constant and pro- bably important change in connection with fecundation and development. The granules of the yolk-substance are ge- nerally rather more densely set together and OVUM. [87] more firmly united towards the external surface, mined by observation in the Mammalia, nor This circumstance has given rise to the belief has any one as yet succeeded in observing a among some observers in the existence of an canal or pore leading from the surface of the additional delicate membrane enclosing the yolk-substance towards the germinal vesicle yolk-mass ; but the most attentive observa- in the mammiferous ovum. tion by Bischoff, Wharton Jones, myself, and others has failed to detect such a membrane ; and there is reason to think that the con- fident belief in its existence has had its origin in part at least in a desire to establish a more complete analogy between the ovum of birds and Mammalia, and to find accordingly a vitelline membrane as well as a chorion present in the ova of the latter. The germinal vesicle is usually about a sixth of the diameter of the whole ovum ; but it is sometimes larger, or between a fifth and a fourth. It possesses a delicate membranous wall of a spherical or spheroidal form and ho- mogeneous structure : it is barely possible to observe the double line of the thickness of this wall with the quarter of an inch lens in the microscope. In most animals the ger- minal vesicle is readily distinguishable from the rest of the ovum by its superior clear- ness, excepting in those instances in which it is hidden by the great opacity of the yolk- substance ; but then it may generally be made manifest by flattening the ovum by compres- sion between plates of glass. The fluid which fills its cavity, which is generally very clear, contains some minute granules in suspension; and besides these there is apparent within it the macula germinativa or germinal nucleus. This last, which is in general well defined in the mammiferous ovum, varies slightly in different animals : in some presenting the appearance of a round globule, with a deli- cate circumscribing line almost amounting to a vesicular covering ; but more frequently it consists only of a small spherical or dis- coid mass of fine granules. In a germinal vesicle of -g^" in diameter, such as that of the rabbit, the diameter of the macula is about one-fourth of that of the vesicle, or 7?1og//. In the earlier stages of formation of the ovum the germinal vesicle is of smaller size ; but it is then proportionally larger than the other parts. It is the part of the ovum first formed ; the yolk-substance, which is subse- quently deposited in gradually increasing quantity round it, together with the zona, grow at a more rapid rate than the vesicle, and thus the latter remains in the mature state proportionally smaller. As the yolk- substance is at first deposited nearly in equal quantity on every side of the vesicle, it for a time contains the vesicle in its cen- tre ; but as the formation of the ovum pro- ceeds the vesicle is found in general to have approached the surface at one side of the yolk-substance ; and in the mature ovum the vesicle seems to be imbedded in the most com- pact and superficial layer of fine granules of the yolk-substance. This place no doubt cor- responds in Mammalia, as has been ascer- tained in Eatrachia, to the point from which after fecundation the first cleavage of the yolk proceeds; but this fact has not yet been deter- Fig. 60*. Ovum of the Rabbit from the E spermatozoa. opian tube with The accompanying figure is introduced to show the usual position of the spermatozoa in relation to the zona and albuminous layer in the ovum of Mammalia during and after impregnation. This ovum is magnified 250 diameters. It was taken along with five others from the lower part of the Fallopian tube 68 or 70 hours after impregnation. The segmentation appears to have proceeded to the fifth stage. There is a thick covering of albumen, over the zona, and a number of spermatozoa are represented involved in the albuminous substance ; some were also seen on the surface of the zona, and some, varying in number in the different ova observed from five to seven or nine, were clearly ascertained to be situated within the zona on the surface of and in the grooves between the yolk segments. The position of these last is not s'uffi- ciently clearly represented in the figure. In the situation now described the germinal vesicle, though not by any means firmly fixed, is yet sufficiently embraced by the yolk- substance to prevent it from changing place when the ovum is moved in different direc- tions. In the instances of the more fluid condition of the yolk it flows freely out from within the zona when this has been broken ; but in those ova in which the yolk-substance is more viscid, as in the human ovum, we ge- nerally fail to isolate the vesicle from the rest of the substance. The macula or nucleus appears to be at- tached to the inner surface of the membrane of the germinal vesicle. This is especially seen to be the case in the Pig, in which the macula seems to be somewhat pyriform or pediculated (see Jig. 61*). No important changes have been observed [G 4] [88] OVUM. Fig. 61 •. the cow. Upon the question how far these varieties in the structure of the ovum may be supposed to be related to the origin of Double- monsters and Twins, I must refer to Pro- fessor Vrolik's interesting article Teratology.* For the assistance of those who may wish to engage in researches of the same nature as those by which the above facts have been as- certained, I will state shortly the manner in which the ova of Mammalia may be procured either from the ovary or after they have left that organ. 1st. For the examination of the earlier ovarian ova and follicles, thin sec- tions of the ovarian substance are to be made, especially towards the surface of the ovary; and some of these are to be teased out with needle points, and examined with the aid of compression, &c. 2nd. For the more mature ovarian ovum, &c., the outer covering of the ovary is to be removed from the surface of one or more of the pro- minent follicles ; and the latter may then, if large, be carefully dissected out of the ovary, and laid on a glass plate, where it is to be opened with a sharp-pointed knife, and its contents are to be gently pressed out on the glass. The ovum may in general be easily detected in a part of the tunica granu- losa with a low magnifying lens, or even sometimes with the naked eye. In the ovary vitellus jfo" ; the germinal vesicle fa" ; the ma- of the dog the ovum may sometimes be seen cula yjLj" ; thickness of the zona yfaf. The ovum without any dissection towards the most Ovarian ovum of the Sow. This ovum is represented in order to show the peculiar pyriform shape of the macula iu the ger- minal ves'icle, to the wall of which the macula appears to be attached. This ovum was taken from a Graafian follicle of TL" in diameter. The following are the dimensions of its several parts which are magnified 250 diameters in the figure. The ovum across the exterior of the zona " ; the is surrounded by the thick layer of cells which form the granular disc, dp. A few cells of the thinner membrana granulosa are represented at tg. to occur in the germinal vesicle during the ovarian existence of the ovum. It usually prominent part of the surface of the ma- ture follicles, t 3rd. To procure the ova after they have left the ovary, or while they are in the tubes, two methods may be pur- sued : either the whole length of the tube disappears in Mammalia previous to the es- ™*f be .°Pened *ith very finely-pointed and cape of the ovum from the Graafian follicle ; sharP SCIS?ors> and rth« surface *hen sPread ?ut and examined carefully with a low magnifying power under a good elumination, but this must not be done under water ; or another but in this class of animals the phenomena attending the disappearance have not yet been fully investigated. There are some ids fc grounds for believing that immediately pre- P vious to the bursting of the vesicle there may be changes of the macula and other contents of the vesicle of a corresponding nature with those which have been more clearly observed in Batrachia and Fishes. Dr. Martin Barry seems to have observed something of this kind, and M. Coste has figured, but not so far r be followed according to the re- commendation of Martin Barry, founded on a suggestion thrown out by Cruickshank, as follows : The Fallopian tubes being divided into several portions, the contents of each portion are to be separately pressed out by passing a blunt instrument firmly along the outside of the tube, and, being placed on suit- as I am aware described, the development of able Plates of glass, are to be subjected to the cells in the germinal vesicle of a ripe ovarian necessary examination. The latter method human ovum. R. Wagner states, that occasionally a double macula may be seen in the germinal vesicle. f I have on one occasion observed two germinal vesicles within the same ovum in the dog. Bischoff has on three occasions observed two ovules in the same Graafian follicle of the rabbit. "| This had been previously noticed b Von Baer in the dog and pig. And Bidder detected two ovules embedded in the same granular membrane of one Graafian vesicle of * See the'plate in his great work marked " Mam- miferes ; Homme." PI. J. Fig. 6. is particularly convenient in small animals : in the larger I have followed both plans. The method of Barry certainly saves much time and trouble, and is on the whole sure enough.]; 4th. Of the plan for obtaining the ova from the uterus, when of considerable size, as it belongs rather to the history of develop- ment, I will only say here that the greatest caution is necessary in cutting through the walls of the uterus in different layers so as to p. 973. Cyclopaed. of Anat. and * Vol. Physiol. t See Von Baer's Commentary on his Epistola, f See Prodromus Hist. Generationis, Fig. xxxi. in Breschet's Repertoire, 1828, p. 38. j Muller's Archiv. Jahrsbericht, p. 1G9. J See Barry's Second Series of Researches, &c., § Mttller's Archiv. 1842, p. 86. Phil. Trans. 1839, p. 366. OVUM. [89] avoid injuring the ova, and that the examina- tion must be made at first in the dry state. Origin and Formation of the Mammiferous Ovum. — This subject has already been ad- verted to in the previous section in connection with the history of the formation of the bird's egg. Dr. Martin Barry was led, by his numer- ous observations, to form the conclusion, that the germinal vesicle is the first part which makes its appearance in the ovarian stroma at the commencement of the formation of the ova. All observers seem now to be agreed, that of the parts belonging strictly to the ovum itself, the germinal vesicle is the first formed ; but the observations of Valentin, Bischoff and others appear rather to support the view, which is opposed to that of Barry, that the Graafian follicles may be detected in the ovarian stroma before any part of the ovule is distinguishable. The ovules are formed at a comparatively early period in the ovary. Carus was the first to point out * that in the ovary of the human female child the follicles con- taining distinct ovules are perceptible at birth. Vallisnieri had long previously, it appears, made a similar observation. Bis- choff has, with more precision, pointed out, that there is considerable variation in dif- ferent children of the same aize as to the degree of advancement of the germs of ova within the ovarium ; in some nothing more than a perfectly uniform ovarian stroma is perceptible at birth, while in others the follicles are distinctly formed, even at an earlier period. By the age of ten or eleven years a number of the vesicles are found to be approaching ma- turity, and almost all have left their earliest condition. Both Barry and Bischoff, how- ever, are of opinion that new sets of Graafian follicles and ova may continue to arise within the ovaries during the whole child-bearing period of the human female; and there can be little doubt that this takes place in most of the lower animals. Bischoff describes the Graafian follicles as taking their origin from minute heaps of granules in the ovarian stroma; but he has not been able to confirm the statement of Valentin that the earliest follicles proceed from primitive gland tubes stretching from the attached border towards the surface of the ovary, f In various animals the follicles and ova begin to be formed at an earlier period than in the human female : according to. Bischoff, they arise very early both in the cow and pig. When the primary follicle can be perceived, it consists of a small vesicle scarcely more than Sijoo// in diameter. To this primary vesicle artin Barry has given the appropriate name of Ovisac. Soon afterwards, when the vesicle has expanded somewhat, it is found to con- tain the rudiment of the ovum ; first in the shape of the very small germinal vesicle, gene- * Muller's Archiv. for 1832, p. 379. t Handbuch der Entwickelungsgeschichte, 1835, p. 389. ; and Muller's Archiv for 1838, p. 529. Fig. 62 *. Development of the Ovarian ovum of Mammalia. (From Bischoff.} A represents a very small portion of the ovary of a foetal dog. The commencing Graafian follicles are visible in the granular or cellular stroma of the ovary, constituting dark heaps of more opaque granules or small cells. B, fragment of the ovary of a dog three weeks after birth. The Graafian follicles are now seen in the fibro-granular ovarian stroma, each surrounded by a homogeneous and fibrous covering, and filled with granules. c, fragment of the ovary of a pig three weeks old. The Graafian follicles are now seen to be formed of a fine transparent vesicular membrane, and round the larger ones fibres are beginning to be deposited. The wall of the follicles are lined internally with delicate epithelial cells. The ger- minal vesicles now visible within consist of a fine clear cell with a nucleus or dot, and a few vitelline granules have begun to be deposited round the germinal vesicles. g, one of these Graafian follicles burst with a needle, showing the contents of the follicle; there being as yet no zona or vitelline membrane. rally surrounded by a small quantity of granu- lar fluid. Soon afterwards the outer follicle is lined with a few extremely delicate or hya- line hemispherical cells, which have somewhat the appearance of those of epithelium, and which thus give rise to a clear space between [90] OVUM. the membrane or wall of the follicle, and all that yet exists of the ovule. Next, the yolk substance is formed round the germinal vesicle ; first of all, as has been shown by Leuckartf, by the deposit of a clear viscid fluid, and next by the formation of dark or opaque small granules in this fluid adjacent to the germinal vesicle. Somewhat later the zona pellucida, Fig. 63 *. Ovarian follicle and ovum of the Rabbit at an early stage. The follicle here represented was about yL- in diameter : in the figure it is shown as it appears tinder slight pressure. All the parts of the ovum are distinct, and its large size in proportion to the follicle and tunica granulosa is apparent. In the lower of the two figures the follicle is represented as having been burst by pressure and the ovum •with the tunica granulosa in the act of escaping from within : the yielding character and elasticity of the zona is shown by the change of form during the escape, and the ovum afterwards regaining its spherical shape, o, the wall of the follicle ; t g, the tunica granulosa; z, the zona partially freed from the cell covering. The macula with the germinal vesicle is remarkably distinct, and is surrounded by a quantity of fine molecular substance. which cannot be said to have existed from the first, comes to be apparent outside the opaque granular substance of the yolk, and close to the epithelial cells which line the follicle: it seems as if it owed its origin to the condensa- tion of the outermost layer of the clear base- ment matter from which the yolk-substance is formed. The membrana granulosa consists for a time of a single layer of nucleated epithelial cells situated between the ovule and the Graafian follicle. The latter not being yet expanded by fluid, is at this period completely filled by the ovum. Such is the state of the parts, now all present, in follicles of from T£Q to jnyj/' in dia- meter. Subsequently the follicle increases in size much more rapidly than the ovum ; the membrana granulosa follows closely the wall of the follicle in its rapid expansion by the increasing accumulation of fluid within ; and the ovum is now found to be imbedded in a particular portion of the layer of granular cells constituting the cumulus. According to the best observations, then, as to the formation of the mammiferous ovum, it appears that the ovarian follicle, which we may look upon as the primary gland cell, is first produced ; that within it at a very early period the germinal vesicle with its nu- cleus next arises, and that very soon after the origin of this primary part the yolk-substance commences by a deposit of fluid and granules round the germinal vesicle ; that the Graa- fian follicle is lined by a layer of nucleated cells resembling epithelium, which constitute the commencement of the tunica granulosa ; that the zona pellucida, which forms the outer- most covering of the ovum when it leaves the ovary, is formed at an early period, but some- what later than the commencement of the other parts of the ovum ; and that it probably owes its origin to a membranous condensation of the outermost part of the clear primitive yolk-substance ; and that, finally, the tunica granulosa increases in quantity and extent, is expanded along with the follicle by the fluid within it, and being deposited at its thickened cumulus round the ovum encloses it in a part of its substance. The structure of the ovum is, on the whole, very similar throughout all the families of the class Mammalia in which it has been examined, excepting one, viz., the Monotremata. In Marsupialia, in which, from the remarkable deviation from the more common mode of gestation, it has been supposed that the ovum might present some peculiarities, it does not appear, from the observations of Professor Owen, that any remarkable difference is to be detected. In the ovisac there was observed a somewhat larger quantity of granular sub- stance than usual ; but the diameter of one of the largest ova in the Macropus Parryi or Kangaroo was not greater than T^", and the germinal vesicle was only Te*g-t/', which is proportionally small ; so that it cannot be held that in this animal there was apparent any + Article Zeugung in Wagner's Hand wort erbuch approach to the oviparous type, der Physiologic, 1853. In the Monotremata, however, the ovum is OVUM. [91] of much larger size, and appears to occupy the whole or the greater part of the ovarian follicle or capsule ; more in the manner of that in birds and scaly reptiles. According to Professor Owen*, the ovaries of the Orni- thorhynchus present numerous elevations on their surface caused by the projection of ovi- sacs of different sizes and in different stages of development. The largest of these sacs have a diameter of two lines ; and, as in birds, though in a less marked manner, the right oviduct and ovary are less developed than the left. The unimpregnated ovum nearly com- pletely fills the ovisac or ovarian capsule. The germinal vesicle is of a comparatively large size, being about ^5^" in diameter. The vitelline substance is rich in nucleated (?) cells or granules, intermixed with clear co- lourless oil globules. The vitelline membrane is moderately thick and smooth, and refracts light strongly. The ovum is separated from the inner surface of the ovarian capsule by a very small quantity of fluid, and by a stratum of granules or cells. The ova found in the uterus of the Orni- thorhynchus were of a deep-yellow colour, with a smooth polished surface, and had no adhesion to the inner uterine membrane. In one animal the yolks were found enclosed in a more transparent mass, which was sur- rounded by a cortical membrane of some te- nacity, presenting in fact some resemblance to the albumen and shell membrane of a bird's egg. Leuckart f thinks it probable that Owen may have been misled as to the size of the ova by the examination of specimens which had been preserved in alcohol ; but Professor Owen informs me, that he was fully on his guard against such an error, and was quite satisfied of the approach in the struc- ture of these ova to the oviparous type of birds and reptiles. I have examined the ovaries in a specimen of Echidna hystrix, which has been preserved in alcohol ; and although the somewhat de- teriorated state of the specimen, and the cir- cumstance of the ovaries not being in the fully developed condition, were not the most favourable for minute observation, I was con- vinced that the ovarian ova of this animal, like those of its congener the Ornithorhyn- chus, belong rather to the oviparous than to the usual mammiferous type. The yolks, which quite filled the ovisacs, were soine of them about ^ " m diameter : they contained a large quantity of granular globules similar to the yolk corpuscles of birds ; the yolk, in fact, consisted of the nutritive as well as the formative substance ; and the whole aspect of the ovary, as well as of the individual yolks, recalled to my mind that of an oviparous animal in a somewhat undeveloped state. * See Prof. Owen's Article Monotremata in this Cyclopaedia, and his Memoirs in the Philos. Trans, for 1832 and 1835. See in particular figures 191, 192, and 194 of the article Monotremata, Cylopsed. of Anat. vol. iii. p. 393, et seq. •f Article Zeugung, p. 783. The ova of a considerable number of the Invertebrate animals belong to the same group under which I have placed that of Mammalia; that is, they consist principally of formative or granular yolk-substance, un- dergo complete segmentation, and have a simple zona or structureless covering ; but yet the varieties in structure, relations, ancj mode of production among these ova them- selves, and their differences from the ova of Mammalia are so great, that I think it will conduce to greater clearness and prevent repetition, to defer treating of the ova of In- veitebrata till after I shall have given the description of the remaining ova of the Ver- tebrate animals, to which we shall now pro- ceed. Third Group of the Ova of \rertebrate Animals. — Under this head I have now to state some details as to the structure, relations, and mode of formation of the ova of amphibious reptiles or chiefly the Batrachia, and of osseous fishes. The ova of both of these tribes of ani- mals appear to occupy an intermediate place be • tween the very small and granular-yolked ova of the Mammalia and the large cellular-yolked ova of birds and scaly reptiles. They agree in both possessing a yolk of moderate size, in the substance of the yolk being principally or largely of the formative kind, and in the possession of a proportionally large germinal vesicle, in which the macula is not a single nucleus, but rather a large collection of nuclei or maculae. In both of them the segmentation is partial or not complete, affecting chiefly the superficial part of the yolk, in which the formative or germinal portion of the yolk is placed, but varying considerably in the depth and the extent of the surface which it involves in different species and genera, more espe- cially among the Amphibia. In the predomi- nance of the formative yolk and in its rela- tions to the process of segmentation, there- fore, they approach the Mammalia, while in the large size and structure of the germinal vesicle in all, and in the considerable amount of nutritive yolk in some, they more nearly resemble the group of large-polked ova. It will be proper, on account of the differences between them, to describe separately the ova of Amphibia and those of Osseous fishes. Amphibia. — Batrachia. — The ripe ovarian ovum of the common frog cr toad is a nearly spherical body of from TaT to J^ of an inch in diameter, of a dark colour, contained with- in and closely embraced by a thin vascular sac formed by the dilatation of the ovisacs which hang into the general ovarian cavity. Tin's capsule or ovisac is attached to the rest of the ovarian substance by a broad band rather than by a narrow pedicle; and when the yolk or ovarian ovum is mature, it escapes from the ovisac by the formation of an aper- ture in the remote or free side of this capsule, somewhat in the same manner as occurs in the calyces of the bird, but with a wider aper- ture. Through the apertures of the general ovarian capsule the numerous ova pass into the abdominal cavity, during the first period OVUM. of sexual union, and they are thence taken up singly by the open upper extremities of the two oviducts ; through the whole of which canals they descend, and in their passage receive an additional covering of a peculiar gelatinous or albuminous substance, which adheres closely to the surface of the yolk membrane, and is firm and of comparatively little bulk while the ova are still within the oviduct, but which after exclusion rapidly. swells by the im- bibition of a large quantity of water, so as to become several times its original thickness, and to assume a soft gelatinous consistence. The ova which have passed through the oviducts remain for a time accumulated in large numbers in a dilated part of the canals near their lower end, until the whole or greater part of those which are ready to descend from the ovary have passed down ; and then, while the male still continues united with the female, the ova are rapidly excluded, and the male sheds the spermatic fluid in abundance, partly on the ova as they pass into the water, and partly after separating from the female, upon the spawn as it floats in the water. The importance of the imbibition of water by the gelatinous covering immediately on the exclusion of the ova and just at the time when the spermatic fluid has been placed upon them, in securing the access of the sperma- tozoa to the surface of the vitelline membrane through the stiff jelly, and in thus promoting fecundation, will be afterwards more particu- larly adverted to. In the tailed Amphibia, such as the differ- ent kinds of Newt (Salamandra, Triton, and Lissotriton) there is not the same union of the male and female as in the tailless or Anu- rous Batrachia ; and impregnation takes place by the entrance of the spermatic fluid, shed in the water by the male while placed near the fe- male, into the oviducts of the latter. In these animals the external covering consists of an elliptical membranous capsule filled with a clear fluid and containing the coloured sphe- rical yolk ; but there is also externally a small quantity of gelatinous substance which in some of them serves to attach the ova to leaves of plants orjrther objects. In the common larger and smaller newts the ova are in smaller number than in the frog or toad, and are excluded one by one by the female, which deposits them singly in a folded leaf or other place of security.* The yolk of the ripe ovarian ovum in Am- phibia consists of a thick opaque mass of vitelline substance, within which and towards one side the large germinal vesicle is placed. The vitelline substance is usually of a darker colour on the exterior and lighter in the cen- tre. In the common toad the superficial part is almost black ; in the common frog, Rana tcmporaria, it is of a very dark brown ; and it is in different other species of various hues, as * I have frequently observed this process, which has been beautifully described and figured by Mauro Rusconi in his work, " Amours des Sala- mandres Aquatiques, Milan, 1821." stated in a former part of this article. The dark superficial part does not in general cover the whole surface of the yolk, but is deficient on one side ; and its extent as compared with the inner paler part, which appears where the dark part terminates, varies in different spe- cies and is greater in proportion to the de- gree of advancement of the ova. In some species, as in the Alytes obstetricans, of which C. Vogt has given an excellent description-}-, it does not, when the ovum is mature, occupy more than a half of the surface ; but in the common frog and toad it covers so much of the surface of the yolk when it is about to leave the ovary, that the gray internal part is only seen as a defined round spot on the opposite side. In the undeveloped ovarian ova, however, the dark part is much more limited in its extent, thus allowing a greater part of the lighter-coloured internal part to be seen. Fig. 64 *. Ovum of the Frog. a. (From Newport.') An ovum of the frog half an hour after impregnation, covered with its gelatinous mass. The dark part of the egg or yolk is seen to be surrounded by a vitelline membrane. Sperma- tozoa were seen everywhere in the gelatinous en- velope, but are not represented in the figure. b. Vertical section of the yolk or ovarian ovum of the frog which has been hardened in alcohol, showing the germinal vesicle within and the canal of the yolk which leads down to it from the upper or germinal pole. The external line indicates the vitelline membrane. c. Diagrammatic representation of the same sec- tion, showing, according to the views of Ransom, the relation of the canal or depression of the yolk to the germinal vesicle. The micropyle, if it exists in these ova, may be situated in the vitelline membrane immediately above this canal. This figure also shows the relations of the dark and light coloured parts of the yolk substance. f Entwickelungsg. der Geburtshoelferkrote, Solo- thurn, 1842.. OVUM. [93] It is towards the centre of the dark super- ficial part of the yolk that the first changes of embryonic development always take place ; and it is apparent that this dark part corre- sponds more immediately to the germinal part of ihe yolk. It is beneath the central part of this dark covering that the germinal vesicle is situated in the ripe ovum. When taken from the ovary previous to impregnation, the ova float in water indifferently as regards the position of their parts ; but after impregna- tion, when the imbibition of water allows of the free rotation of the} oik within its cover- ings, it is invariably found that the dark or germinal part of the yolk is directed upwards, and the whiter or grey spot downwards ; — a circumstance by which the difference between the fecundated and the unfecundated ova may readily be detected. We may dis- tinguish therefore, as the upper, dorsal, or germinal pole of the ovum, the central point of the dark part, and name the opposite point in the centre of the light-coloured space the lower or ventral pole. The thickness of the dark layer of substance which covers the upper part of the ovum is throughout its greater part considerable ; viz. about one-eighth to one-tenth of the whole diameter of the yolk. It thins off somewhat at its edges below. Within this darkest layer the colour of the yolk-substance is slightly shaded off into the grey substance of the in- terior : the consistence of the inner substance is less than that of the superficial layer, and it contains a cavity situated considerably nearer the upper than the lower surface of the yolk, in which the germinal vesicle is situated. This vesicle is not perfectly sphe- rical in its form, but somewhat flattened from above downwards, and it is surrounded by a peculiar mass of fine granules. The yolk-substance contains no cells nor large corpuscles ; the greater part of it consists in the mature state of peculiar flat or tabular cor- puscles, the largest of which are about 2 aW" in diameter. Most of these are quadrangular in shape, but somewhat rounded on the edges and at their angles. There are also numerous smaller particles of the same kind of every di- mension from that already stated down to the smallest granules, and with some variation of shape, together with a considerable amount of molecules of very minute size, of which those in the darker part have the appearance of pigment granules. These last are accumu- lated in greatest quantity towards the surface ; but they do not constitute a separate layer, being rather interspersed with the tabular cor- puscles. There are also to be seen in the upper or germinal part a few rounded corpus- cles, somewhat larger than the tabular particles, which seem to be formed by the aggregation of smaller molecules ; but these have no ex- ternal envelope nor clear nucleus, and only bear a distant resemblance to the cells which, after impregnation, are formed in the germinal part of the yolk-substance. The peculiar quadrilateral tabular corpuscles refract light strongly, so as to present distinct outlines ; they have also considerable firmness, resisting pressure, but by force may be broken up somewhat in the same manner as would occur in small plates of wax. From this cir- cumstance they have generally been regarded as of a fatty nature, and were described by Vogt as stearine tables; but Virchow*, from a careful investigation of their reaction with different substances, throws a doubt upon this view, and is more inclined to regard these cor- puscles, both in Batrachia and in the ovum of the carp-fish, as composed of some albuminous or protein principle, the exact nature of which he has been unable to determine. He admits that they may also contain some oil. They are probably very analogous to the larger firm angular particles which were first de- scribed by J. Muller as forming the greater part of the yolk-substance in the Sharks and Rays, and which also exist in the ova of Cephalopodous Mollusca.-f- The germinal vesicle of the Batrachian ovum is of very large proportionate size. According to Vogt, in the Alytes obstetrlcans its diameter is nearly equal to one-third of that of the entire yolk mass. In the common frog and toad it is somewhat less, but nearly -fa of an inch. This vesicle may be obtained separate for examination by breaking open the yolk care- fully under water ; but it is much easier to observe its position, form, and structure in the ovum which has been hardened by some re-agent, — a plan which has been successfully adopted by a variety of observers. Cramer f recommends for this purpose alcohol, or more particularly dilute chromic acid; Newport $ employed alcohol, as I also have done with success ; more recently Remak || states that he has found a mixture of a solution of sul- phate of copper with alcohol, to which a few drops of rectified wood spirit are added, pecu- liarly fitted to give the proper consistence to the various parts, without inducing any de- structive change in their structure or appear- ance. All observers agree that there is scarcely any other animal in which the re- lations of the germinal vesicle to the other parts of the yolk can be more favourably in- vestigated. The enclosing wall of the vesicle is of ex- treme tenuity, so thin, indeed, that some have doubted its existence. I have been able, how- ever, to distinguish the double outline of its thickness with a good magnifying power of 350 diameters. The outer surface of the vesicle is not always of a regular circular or spherical form, but often presents within the yolk, both at earlier and more advanced stages, a notched * Zeitsch. fur Wissensch. Zool. vol. v. p. 241. t See J. Muller, uber die Glatten Hai des Aristo- teles, 1842, p. 36. J Bemerk. iiber das Zellenleben in der Entwick. des Froscheies, in Miillers Archiv. 1848, p. 20. § Researches on the Impregnation of the Am phibia, First Series, in Phil. Trans, for 1851, p. 169. et seq. || Untersuch. uber die Entwickel. der Wirbel- thiere, Berlin, 1855, p. 127. OVUM appearance: when, however, the vesicle has been extracted from the yolk, I have gene- rally found this appearance to be removed and perfect sphericity restored. It would appear also, from Vogt's observations in Alytes, that this appearance is not constant : it may depend on the viscidity of the contents, and the ex- treme softness and thinness of the enclosing membrane of the vesicle. It is only in the earliest stages of ovarian for- mation that any appearance of distinct maculae, such as they have been described in other animals, is to be perceived ; for from a very early period these spots or nuclei are already very numerous. As the ova approach matu- rity the contents of the germinal vesicle un- dergo very considerable and rapid changes, by which a number of corpuscles, some loose, others aggregated, and subsequently delicate cells, are formed, and completely fill the whole cavity of the vesicle. The germinal vesicle is situated, in the ripe ovarian ovum, nearer the upper than the lower part of the yolk. When the egg has been hardened by the re-agents already re- ferred to, there can be perceived in the middle of the upper surface, or exactly in the upper or germinal pole of the yolk, a minute depression, which was first noticed by Prevost and Du- mas *, and which they, erroneously, according to most of the observers who have followed them, conceived to be connected with an aper- ture or pore in the external membranes of the ovum. Von Baer showed that this depres- sion leads into a canal which extends from the upper pole of the yolk, through the yolk- substance, to the surface of the germinal vesicle. The existence of this canal has been fully established, and its situation well repre- sented by Newport. The interval between the upper surface of the yolk and the germinal vesicle appears to become less as the ovum approaches maturity. The vitelline membrane of the mature ovarian ovum in the frog is thin and homoge- neous. In the ova which have escaped from the ovary into the abdominal cavity it is still so thin, that they are very liable to be broken by the slightest force applied unequally on their surface; but in their descent through the oviduct considerable consistence is given by the addition of the layers of albumen to the vitelline membrane. Besides the simple vitel- line membrane, there appears to be a second envelope formed within the albuminous de- posit. Remakj", indeed, describes the vitelline membrane itself as consisting of two layers, besides the superadded membrane within the albumen. Formation of the Ovum, and Changes in its Progress. — The ovary of the Batrachia is peculiarly well adapted for making observa- tions on the development of the ova, as the stroma is in small quantity and transparent, and as it contains at most seasons a considerable * 2me Mem. sur la Generation, &c., in Annal. des Scien. Nat 1824, torn. ii. p. 104. t Loc. cit. p. 127. number of ova in different stages of their for- mation and progress. If examined in the autumn or in spring before pairing, there are generally found three sets of ova ; one uniformly large and dark-coloured, obviously belonging to those which are about to be brought forth in the ensuing breeding season ; another set, also of uniform size, but less than the first, and in which only a partial deposit of colouring matter has taken place, probably constitute the ova for the next season after the first ; and, third, a number of ova of inferior magnitude to either of the other sets, and of most various sizes, down to the most minute, which we may suppose to comprise those de- stined for succeeding breeding seasons. It seems probable that three seasons are neces- sary for the full development of the ova in the common frog and toad. The earliest ova are seen within the ovi- capsules or ovisacs, in the delicate ovarian stroma ; the more advanced are enclosed in their pediculated capsules or calyces. The germinal vesicle is the part of the ovum first distinctly recognisable; but so soon as it, or any part of the ovum can be distinguished, the delicate membrane of the ovisac or ova- rian follicle is also seen surrounding it. Leuckart* was never able to perceive a fol- licle without there being already also an ovum within it. It would appear, therefore, either that the follicle and germinal vesicle arise together, or that observations have not yet determined which of them has the priority. It has been stated by some, that in the very earliest periods a single macula or nucleus may be observed in the germinal vesicle f ; but it is rare to find the germinal vesicle in this state, and I have generally observed the macula, even in the earliest stages, to be multiple, or to con- sist of several maculae. Still it is undoubted that, in the earliest period, there are fewer maculae than at more advanced periods, and that their number gradually increases. About the time of maturation of the ovum the con- tents of the germinal vesicle undergo further changes, to which reference will hereafter be made. From a very early period, though perhaps not from the first, the germinal vesicle is sur- rounded by a thick viscid substance, which closely adheres to its surface. This substance is at first remarkably clear, especially at its outer part, where it has a hyaline appearance : a little later it becomes gradually more and more opaque, as if by the deposit in or mix- ture with its clearer substance of fine mole- cules or granules. This appears to be the primitive yolk-substance ; which in these ani- mals therefore, as inmost others, is ascertained to consist of a clear basis or matrix, in which the granular part is suspended. The out- * Loc. cit. t Mr. Newport describes the germinal vesicle of the frog's ovum as nucleated, even when half-grown. He also speaks of the corpuscles of the yolk sub- stance as "nucleated cells" (1st Series, p. 176.) ; but this is quite inconsistent with the statements of most other observers. OVUM. [95] Fig. 65 Formation of the ovarian ovum in the Frog. A, and B. Magnified representations of an ovarian follicle and its contents in an early stage of the formation of the ovum. The follicle is ^y in diameter : in A the follicular membrane and its epithelial lining are chiefly brought into focus; in B the parts of the ovum" within are represented when the microscope was adjusted so as to place them in focus. The wall of the ovarian follicle con- sists of a structureless membrane or ovicapsule, and an external covering of thin flattened cells; the epithelial cells of the follicle within are seen in pro- file towards the margin, and full towards the centre (in A) where their granular contents and nuclei are distinct. In the centre of B the large germinal vesi- cle with numerous maculae is seen ; around it a clear space which is a part of the basement substance of the primitive yolk, and between this and the wall of the follicle there is seen superiorly the dark granular mass which has been called yolk nucleus. The clear primitive yolk is also surrounded by a finely granu- lar vitelline substance which has begun to be de- posited. line of the clear part remains remarkably smooth and well-defined for a time, and inner surface of the ovicapsule. The homoge- neous membrane of the latter is found at an early period to be lined by a single layer of very distinct largely nucleated cells, which lie flatly applied against its inner surface, but bulge or project roundly on their other sides towards the ovum. This layer of cells no doubt cor- responds to the tunica granulosa of the ovisac in other animals, and has a similar destina-* tion. There is as yet, neither in the earlier ova nor in those half-grown, any zona or other proper vitelline membrane ; and it it? obvious that what some authors* have described as such could be nothing more than the distinct surface of the primitive yolk. Whether this surface becomes condensed into a membrane, or at what time this may occur, has not yet been determined by observation. Besides these parts in the early Batrachian ovum, there is another which has frequently been seen by various observers from Von Baer downwards, and which, as it is different from anything that has been observed in the ova of other Vertebrata, deserves some atten- tion ; I refer to a dark mass of granules situ- ated excentrically or towards the side of the clear primitive yolk-substance, and between it and the tunica granulosa of the ovisac, and which, from its supposed connection with the formation of the yolk-substance, has been called the yolk-nucleus. This mass may easily be seen in ovisacs of the common frog of from y4^ to ^^ of an inch in diameter. It is then about one-tenth of the diameter of the ovisac. It is very opaque as compared with the other parts, being composed of ag- gregated heaps or small balls of finer granules. The opaque granules of the yolk have been supposed to be derived from this body, and it has been alleged that, as the yolk-substance increases, this yolk-nucleus gradually disap- pears or spreads itself round the germinal vesicle, y Leuckart, however, states that this body is not invariably present, and that it is subject to considerable varieties, and he is not inclined to attribute to it any important function in connection with the formation of parts of the ovum. I have in general ibund it present, and think it more probable that it may be destined to form the external and larger corpuscles of the yolk, while the clearer part immediately surrounding the germinal vesicle may contribute to the production both of these and of the finer substance in which the germinal vesicle is found imbedded. But farther observations will be required for the determination of these points. As the growth of the ovarian ova proceeds, the deposit of fine granules in and around the primitive albuminous yolk-mass increases rapidly ; and the yolk- nucleus, becoming less distinct, finally disappears at an early but somewhat variable period. The yolk-sub- * As Cramer, loc. cit. p. 21. See V. Carus in Zeitsch. fur Wissen. Zool. vol. there appears to be some fluid or different ii.Tp. 103.; and Ecker in his new edition of K. substance interposed between it and the Wagner's Icones Physiolog. descript. of Tab. xxiii. [96] OVUM. stance contains at first only fine granules ; but in the second season of development there are found mixed with these, especially towards the surface, corpuscles of a somewhat larger size, and these are gradually converted into the quadrilateral tabular particles. The distinc- tion of colour between the surface and the deeper parts, and between the upper and lower portions of the yolk, also now appears; but it is not till the third season of development that, along with a proportional enlargement of the yolk, the darkest kind of pigment is deposited among the corpuscles on the upper surface. The gradual extension of this coloured layer over a greater portion of the surface ofuthe yolk from the upper towards the lower part has already been stated. The extent of the coloured portion marks in fact, in a great measure, the proportion which the immedi- ately germinal part of the yolk bears to that not concerned in the first process of em- bryonic development ; or it indicates at least the extent of the yolk which is immediately involved in the process of segmentation. The vitelline membrane, I have already said, is absent during the early stages of develop- ment of the ovum ; it appears to be present in the third season, but I have not been able to determine precisely its mode of origin. Farther observations are still necessary to ascertain whether, as in Mammalia and some other animals, a zona is formed by the con- densation of the outer part of the primitive yolk-substance, or whether this membrane proceeds from another source. From the gradual flattening and disappearance of the inner cells of the ovarian follicle, and the close adhesion of their remains to the vitelline membrane in the later stages, I am led to be- lieve, that the covering with which the yolk leaves the ovary may owe its origin to the amalgamation of one or more layers of fused or united cells of the tunica granulosa, or to the union of these with the zona or primi- tive vitelline membrane, should such exist. There is no true cellular yolk, but the granular yolk is of proportionally large size ; and if we are disposed to regard the yolk as containing both a formative and nutritive part, these are united or combined in a more close manner than in the larger ova of ovipara. The ova of Batrachia differ, on the other hand, greatly from those of Mammalia in their re- lation to the Graafian follicle ; more especially in the fact of the ovum completely filling the follicle, and the entire absence, excepting in the epithelial lining, of fluid or other deposit between that layer and the surface of the ovum. The history of development shows that the peculiar structure of the ovum of Batrachia, as well as that of osseous fishes, has some connection with the large proportion of the yolk which becomes immediately germinal, and with the comparatively early period of advancement at which the young leave the egg and assume an independent mode of life. Before concluding this account of the ovum of the Amphibia, it will be proper to notice the changes that have been observed in the germinal vesicle near the time of the discharge of the ova, and in its descent through the tubes till its exclusion. All observers are agreed that the germinal vesicle is no longer visible in the excluded ovum, whether fecun- dation shall have occurred or not ; and the solution or disappearance of this vesicle is now looked upon, in these as well as in other animals, as a natural concomitant of the maturation of the ovum independently of fecundation. The recent and very precise observations of Newport* have shown, that in a considerable number of the ova about to leave the ovary but still situated within that organ, the germinal vesicle has disappeared, and that it is invariably gone in all those which have passed into the abdominal cavity. Very shortly before disappearing, and when the ovum is approaching maturity, a remark- able change has been observed in the contents of the germinal vesicle ; which is of great interest, in consequence of its probable intimate rela- tion to the process of segmentation and cell- formation, which follow fecundation and are the precursors of true embryonic develop- ment. These changes have been described first by Cramer, and afterwards by Newport; the latter author, apparently, not having been aware of the observations of the former. In early spring (February) Cramer f found the fine granules into which the maculae of the germinal vesicle had previously been re- solved by multiplication, beginning to unite together into heaps or small masses; and somewhat later he found these masses to become surrounded by a fine membrane or envelope, giving them all the appearance of small cells with a granular nucleus. There are often several hundred such cells at this period in the germinal vesicle of the brown frog, varying slightly in size and shape. At a still later period the greater part of the granular nuclei or contents of these cells become dis- solved, leaving only a few remaining in each ; and finally these also disappear, so as to ren- der the cells entirely clear. Now, all observers are agreed, that in the yolk-substance of the ovarian ovum, previous to the rupture of the germinal vesicle, there are not to be perceived any other solid par- ticles excepting those already mentioned, viz., granules or heaps of granules, and the peculiar quadrangular tables ; but many observers have perceived that immediately after the disap- pearance of the germinal vesicle, and during the whole time previous to fecundation, as well as after that change, the yolk-substance con- tains, mixed with the darker corpuscles, other clearer and spherical vesicular globules, some- what larger than the tabular corpuscles. Vogt described them as scattered through the whole of the superficial yolk-substance in the Alytes obstetricans, and Cramer pointed out that these vesicular corpuscles are identical with the cells which he had observed to be formed in the germinal vesicle immediately before its * Researches, &c., 1st Series, p. 177. t Muller's Archiv. 1848, p. 23. OVUM. [97 disappearance. He attributed their origin, therefore, to this source ; and regarded it as probable that these cells, which may perhaps be descendants of the original maculae of the germinal vesicle (but this is a point which he leaves undetermined), constitute afterwards the nuclei round which the tabular and granu- lar substance of the yolk group themselves ; and thus probably form, subsequent to seg- mentation, the nuclei or foundation of the cells which are the seat of true embryonic development. Newport's description of these changes differs somewhat from that of Cramer, but is not altogether at variance with the view now suggested as to the nature of the process with which they are connected. He states *, that towards the period of maturity he found the germinal vesicle filled with secondary cells, and that each of these contained other or tertiary cells within them, and in the in- terior of these last were granules which he called quaternary. " In the midst of these numerous cells, and in the centre of the ger- minal vesicle, I was able to distinguish," says he, " in some specimens, one or two cells of larger size than the rest, and which I regarded as the remains of the germinal spot or cen- tral nucleus." He further states -f , that these internal cells were, he conceived, afterwards thrown loose by the solution of the parent cells. As to the mode of disappearance of the germinal vesicle, Von Baer had stated f that, it gradually rises from its deeper situation, towards the surface of the yolk, and that, finally bursting or being dissolved there, its contents are allowed to flow over the sur- face of the yolk. This process he also described in several other animals as pro- ceeding in a similar manner; and he sup- posed that the germinal substance from the vesicle was thus diffused over that part of the ovum which is most closely related to the subsequent changes of development. He re- garded the canal of the yolk as the remains of a passage through which the vesicle had been carried to the surface. Newport, on the other hand, is quite confident that no such passage of the vesicle to the surface occurs in the ova of Batrachia, and that the vesicle most pro- bably dissolves or disappears in its situation below the germinal part of the yolk. From the facts he has pointed out, Newport in- fers that the germinal vesicle is burst or de- stroyed by the development of the progeny of cells within it, and that the cells thus set free are mingled with the rest of the yolk. It belongs rather to the history of the changes which the ovum undergoes after fecundation, than to our present subject, to trace the re- lation between the cell progeny of the germinal vesicle now described, and the cells of em- bryonic formation afterwards developed ; but it may be proper here merely to mention that * Loc. cit. p. 176. t Loc. cit. p. 177. I Epistola de Ovi, &c., Fig. Supp. xxr. from the concurrent testimony of several ob- servers, it seems probable that the origin of the blastodermic cells is closely connected with a combination of the vesicles or cells from the germinal vesicle with the other solid elements of the yolk-substance. To this process of cell formation the change of seg- mentation seems, in the Batrachia, as in all other animals, to be the necessary prelude. It may be proper here also to state, in conclusion, that Newport has shown that the process of segmentation begins by a fis- sure which passes in a determinate direction through the canal of the yolk. Although the statement of Prevost and Du- mas as to the existence of an aperture in the membranes of the ovum, through which they supposed the spermatozoa might be introduced in fecundation, has not yet been confirmed by subsequent observers, but has on the contrary, met with an explicit denial from Von Baer, Newport, and Remak, after a very careful examination by these authors ; and although it would appear, from New- port's statement, that the spermatozoa penetrate the vitelline membrane of the frog's egg over a considerable portion of its surface, yet the discoveries which have in the last few years been made as to the ex- istence of the micropyle in fishes and some other animals, are of so unexpected a kind, that we must not regard this point as altoge- ther settled. Dr. Ransom, indeed, in some observations communicated to me, has stated his belief that a micropyle may still be dis- covered in the membrane of the Batrachian ovum. The statement of Prevost and Du- mas on this subject is so precise that it deserves to be recorded in their own words. — " On remarque ensuite qu'il existe au centre de 1'hemisphere brun une tache circulaire tres reguliere, jaune, et marquee d'un point opaque dans son milieu. Celuici provient d'un petit trou dont les deux mem- branes sont percees, ce qui met a decouvert la bouillie brune que renferme 1'ovule. Pour s'en assurer il sufnt de vider 1'ceuf et d'exa- miner a la loupe les membranes transparentes qui sont restees intactes dans toutes leurs parties, sauf 1'endroit qu'on a pique pour evacuer la pulpe qu'elles contenaient." * The observations of Von Baer, Rusconi, Newport, and myself have shown that with certain differences in the form and structure of the external membranes, the colour of the yolk-substance, &c., previously referred to, the structure of the ovum, and the phenomena of change at the time of its discharge, are essen- tially the same in the Newts as in the common Frog. A few observations which I have made on the Menobranchus lateralis and Siredon mexicanum, show that the Perennibran- chiate Amphibia agree very closely with the * See Deuxieme Me'moire sur la Generation :— DeVeloppement de Poeuf des Batraciens, &c., par MM. Prevost et Dumas, in Annal. dea Scien. Nat. torn. ii. 1824, p. 104. [98] OVUM. Salamandrina in regard to the structure and formation of their ova. Osseous Fishes. — The ovarian ova of Os- seous Fishes, while they bear a general resem- blance to those of Vertebrata, among which they come nearest to those of Batrachia, are distinguished by several marked peculiarities. They are of middle size, and possess a strong external covering formed within the ovary. The yolk-substance contains several kinds of elements ; and the germinal vesicle is of con- siderable size. The external membrane is thick, strong, and elastic, and of a peculiar porous structure. The yolk-substance con- tains a large quantity of clear fluid, in which the albuminous granules and yolk corpuscles and the oil globules are suspended, the latter usually of large size and few in number ; the germinal layer or disc is limited to a part of the yolk, varying in size from about a sixth to a half of the circumference, and the process of segmentation in this part after fecundation is consequently more limited than in Mam- Fig. 66 *. Ovum of the Gasterosteus at the time of impregnation. (From Ransom. ) A. An ovum of the Stickleback eight or ten minutes after impregnation, showing the clear re- spiratory space formed immediately upon the access of spermatozoa between the external membrane and the surface of the yolk. Towards the upper part of the figure the situation of the micropyle is indicated by the small projections in the external membrane ; towards the same or upper part of the yolk the germinal disc or layer is easily distinguished from the clearer part of the yolk ; and in the middle a few large coloured oil globules. B. The same ovum about three minutes after im- pregnation, showing somewhat in profile the funnel of the micropyle descending into a depression on the upper surface of the germinal part of the egg. In consequence of impregnation, however, the funnel of the micropyle has begun to rise out of the hollow, and the respiratory space to be formed by the separation of the external membrane from the sur- face of the yolk. malia and most Batrachia ; but more extended than in birds or scaly reptiles. The germinal vesicle contains subdivided or multiple ma- culae. I now proceed to give a few details with respect to these several parts of the ovum. The yolk-mass or yolk-substance consists, in the more mature ovarian ova, of three parts : viz., the clear fluid, which is in great abun- dance and occupies chiefly the centre and the lower part of the ovum; the superficial layer of fine granules, with the vesicular corpuscles; and the large oily globules, which from their less specific gravity are usually situated to- wards the surface and on the upper side. In a number of fishes the clear fluid, which has an acid reaction, becomes immediately turbid or quite thick by the deposit of granular substance when water is added to it. This change is very apparent in the ova of the trout or sal- mon, which, when placed in water, retain their natural clearness and colour so long only as the coverings are entire ; but immediately on their being divided so as to allow of the action of water on the contents, the whole yolk is sudden- ly precipitated as a thick and somewhat tena- cious granular mass. The albuminous matter which surrounds ova that have been spawned has an alkaline reaction. It is an interesting fact, that in these ova, when imbibition of water takes place as a consequence of fecun- dation, no precipitate follows ; but that in unfecundated ova left for some time in the same circumstances without fecundation, though unbroken, turbidity ensues ; so that by the difference of internal appearance the fertile ova soon come to be easily distin- guished from those which have not been fe- cundated.* The solid elements of the yolk- substance appear to be in general of three kinds for some time before the ovum has arrived at maturity : viz., 1st, a quantity of small granules comparable to the granular yolk-substance of the primitive ovum ; 2nd, collections of clearer vesicles and globules interspersed with the first, and in general partly mixed with them and partly situated in a deeper layer ; and, 3rd, the large oil glo- bules. These last are usually somewhat co- loured ; they are comparatively large, and m some fishes are very few in number, and even reduced at last to only one, which is then of proportionally large size. In all fishes, the number of oil globules appears from the observations of Retzius gradually to diminish as the ova approach maturity.f The large oil globules float quite freely in the fluid of the yolk; so that from their greater lightness they always rise towards the side of the ovum which is turned uppermost; but the other elements of the yolk-substance, and especially the small granules of the germ- disc, come in the mature ovarian ovum to occupy one side of the yolk, and, as they form a coherent layer, do not move readily from this place. The smaller granular par- * See a paper by Dr. Davy in the Proceed, of Roy. Soc. of Lond. 1852, p. 149. t See Retzius in Muller's Archiv. for 1855, p. 34. OVUM. [99] tides become more and more circumscribed in a layer on one side of the egg as it ap- proaches maturity, so as to form a germinal disc ; and this occurs independently of fecun- dation. The germinal vesicle is not easily perceived in the ovarian ovum when it has attained some size. This proceeds in part from its ex- treme delicacy and transparency, and also from the opacity of the granules of the yolk within which it is situated. But it is to be observed also, that it disappears proportionally sooner than in other vertebrate animals. It is of con- siderable size in proportion to the rest of the ovum, having a diameter not unfrequentlyof -^ or g\/' m ova °f sV- It 'ls never to be found in ova that have left their capsules in the ovary ; and according to Lereboullet's* observations in the pike and perch, it has already disap- peared for a considerable time before it attains complete maturity. In the earlier stages of the growth of the ovum the germinal vesicle contains numerous distinct maculae ; but in the progress of development these multiply to a great degree, so that the vesicle is at last completely filled with fine clear cells, or bril- liant vesicles, and extremely minute granules. When the vesicle bursts, its contents are dis- persed over the yolk, and very probably are mingled or combined with the layer of germi- nal granules ; but it is not probable, as Lere- boullet supposes, that the whole of the forma- tive layer of the germ (afterwards undergoing segmentation) is produced from the effused contents of the germinal vesicle. This mul- tiplication of the maculae and filling of the germinal vesicle with fine cells appears to be of an analogous kind to that which has been described by Vogt and Newport in the Ba- trachia ; and it seems not improbable that in both classes of animals the dispersed maculae may in some way or other, not yet fully ascer- tained, contribute to the origin and develop- ment of the blastodermic cells in the forma- tion of which the process of segmentation re- sults. It appears certain at least that, after the disappearance of the germinal vesicle and the dispersion of its contents, a marked change takes place in the disposition of the germinal part of the egg by its granular disc or layer becoming more circumscribed and distinct ; and, as Lereboullet supposes, it may then be mingled with the brilliant points which pro- ceed from the contents of the germinal ve- sicle. The process of segmentation, into the de- scription of which it is not intended at pre- sent to enter, is co-extensive with the granu- lar layer or germinal disc of the ovum. The larger yolk globules and the fat cells are not immediately concerned in this process.^ * Resume* d'un Travail sur I'Embryogenie da Brochet, de la Perche, et de PEcrevisse, in Annal. des Scien. Xat. 1854, torn. i. p. 237. et seq. t M. Coste (Comptes rendus, 1850, vol. xxx. p. 692.) has described the germinal disc as being formed only after fecundation ; but from the obser- vations of Vogt, Aubert, Lereboullet, and Ransom, it is ascertained that it exists previously. The membranes of the ripe ovarian ovum of osseous fishes have been described by most recent observers as two in number; viz. 1st, the external tough membrane which some have called chorion or shell-membrane, and others vitelline membrane, which possesses a peculiar structure, hereafter to be described more particularly ; and, 2nd, an extremely delicate film of membrane lying close to the yolk-substance and destitute of visible struc- ture. The latter of these membranes is just discernible in the ovarian egg at the later periods of its growth ; but in ova of two thirds their full size I have failed to perceive it. Dr. Ransom has observed, that in the Stickleback, Gasterosteus aculeatus,this mem- brane becomes more distinctly marked off* from the substance of the yolk subsequent to impregnation, and that it follows the inflec- tions of the surface of that substance during segmentation ; from which he infers, that it is not to be compared with the vitelline membrane as heretofore described by authors in the ova of other animals. The observa- tions which have been obligingly communi- cated to me by Dr. Ransom leave no doubt as to the existence of this inner membrane, and have shown the new and interesting fact that it is possessed of some vital contractile power. It seems probable that it proceeds from a consolidation of the outermost layer of the basement or clear substance of the yolk, in a manner somewhat analogous to the zona pellucida. But I refrain from saying more of it at present, as Dr. Ransom will ere long probably communicate his observations to the public in detail. The external membrane of the Fish's egg which has been deposited in spawning or has been extracted from the ovary when approach- ing maturity, presents a remarkably well de- fined line internally, and is also generally smooth on its outer surface. In some fishes, however, as the perch, it is covered externally with villous, reticular, or other appendages, which serve to connect the ova in masses or strings, in the same manner as occurs with the albuminous matter added to the ova of some Batrachia, but in a less degree. In other in- stances, as the Stickleback, these villi or project- ing processes are limited to one portion of the exterior. This membrane possesses consider- able thickness and tenacity, and usually gives the ovum a nearly regular spherical form when imbibition is complete, as is the case after impregnation. Previous to that change, how- ever, the outer covering of the Fish's egg is more yielding, and possesses so little elasticity, that it usually retains dimples or impressions made upon it from without. Two peculiarities of structure have been observed in this mem- brane which both merit farther attention, and one of which is of great interest. The first of these to which I will refer is the dotted or porous structure of the external membrane. Von Baer* had remarked that the external membrane of the ova of the Cyprinus * Entwickelungsgesch. der Fische, Leipzig, 1835. [H2] [100] OVUM. g enus was not entirely homogeneous, but was marked through its thickness with fine lines set perpendicularly to the surface. Vogt observed a similar structure, and described it more fully in the Salmonidae.* More recently attention has been particularly called to it by the fuller description of the structure of the egg cover- ings in the Perca fluviatilis by Professor MUller of Berlin. In this fish MUller described the radiated lines as produced by fine tubes which pierce the whole thickness of the ex- ternal membrane, beginning with cup or funnel- shaped dilatations on the exterior, preserving a nearly equal diameter throughout, and ter- minating on the inner surface.-]- The tubes have a slight spiral winding as they pass through. That they are really hollow tubes MUller ascertained by finding that he was able to press portions of the coloured oily contents of the yolk through them. Miiller farther ob- served, that in the perch each tube is set in a small prism, which terminates by a hexagonal end on the outer surface. According to Dr. Fig. 67 *. Part of the ovarian ovum of the Salmon. Semi-diagrammatic view of the section of a por- tion of the yolk, porous membrane and external layer of cells in an ovarian ovum of the salmon of 31/ in diameter, a, portion of the yolk substance showing the various granules, granular and nu- cleated corpuscles, and oil globules composing it ; h, section of the porous or dotted external mem- brane ; e, portion of the outer surface of the same turned towards the observer so as to show the punctated or dotted marking produced by the ex- ternal apertures of the fine canals which run through the membrane ; d, the flat surfaces of the nucleated cells (epithelial or granular) which line the ovi- capsule, between which and h they are seen edge- ways lying close along the outer surface of the dotted membrane ; a granular or dotted appearance in the contents of these cells seems to indicate their conversion into the dotted membrane, which is pro- bably formed in successive layers from the exterior. The diameter of these cells is ^0"t that of their nuclei 3Sy. * Embryoge'me des Saumons, Nenfchatel, 1842. t Muller's Archiv. for 1854, p. 186. Ransom's observations, however, it appears that the structure described by Miiller in the perch is peculiar to that fish, and belongs only to an outer covering superadded to the surface of the dotted membrane, which last resembles in all respects that of other fishes. This outer covering appears to be of cellular origin ; and Dr. Ransom thinks it may be due to the separation of the tunica granulosa along with the ovum. The diameter of these tubes in the perch is about 10*o6". In most other fishes the fine lines which ap- pear to be tubular are much smaller. I have observed them in several fishes, and have rarely found more than ten of these tubes in the breadth of fvinr"' anc* tne tuoes them- selves or double lines bounding them were not more than rafon/' or •&&&" in breadth. In looking at the flat surface of the membrane the ends of these tubes give the appearance of a finely dotted structure to the membrane. It is quite possible, however, even where they are finest, to perceive the circle or lumen of the tube by using a high magnifying power ; and I have thought that I could also in the salmon perceive a hexagonal marking of the intervals between the pores (see tfg. 68 * D) ; but in this fish the size of the pores is only a third of that of the tubes in the perch as described by Miiller, and the structure must be of a different kind accord- ing to Ransom's observation. All recent ob- servers have recognised this structure in the external membrane of the fish's ovum. Miiller conceived that the tubes he had observed in the perch might be connected with the intro- duction of the spermatozoa into the ovum ; but Dr. Ransom does not find these tubes to pass entirely through the outer membrane of the perch's ovum, and has observed that the part of the true vitelline or dotted membrane which admits the spermatozoa is destitute of the additional layer ; and it will immediately be shown that in all fishes a special and more direct passage for the admission of these bodies through the dense membrane is provided, con- stituting the second peculiarity of structure in the covering of the Fish's ovum before re- ferred to. The interesting discovery of an aperture in the external membrane of the ovum of osseous fishes is due to Dr. Ransom of Nottingham, who observed it first in two species of Stickle- back or Gasterosteus, and afterwards in other fishes. This author made the farther interest- ing observation in the first-mentioned fish, that in impregnation the spermatozoa entered the ovum only through this aperture or mi- cropyle. As this is the first instance in which the existence of this aperture and its relation to the process of fecundation have been ascertained by direct observation in a vertebrate animal, I will describe it more fully from Dr. Ransom's paper to the Royal So- ciety of London*, and from farther inform- ation which he has obligingly furnished to me in private. I may also mention that I have fully confirmed Ransom's observations as to * Proceedings of Roy. Soc. 1854, Nov. 23rd. OVUM. Fig. 68*. ;^£:g XY-. •;.'•'•;• ':•>:' >:.'i;'r:' .-.•.•' Micropyle of the ovum in Osseous Fisfies. A. Enlarged view of a quadrangular portion of the surface of the mature ovarian egg of the Stickleback containing the micropyle from above. In the outer part of this figure the'general dotted appearance of the membrane is seen, and here and there the pedicu- lated flask-like processes attached to the membrane in this fish in the vicinity of the micropyle ; the radiated shading represents the appearance of the funnel-shaped depression leading to the aperture of the micropyle, which is seen in the centre of the space it encloses. B. Transverse section of the dotted membrane and funnel of the micropyle of the same egg some- what more enlarged, seen in profile ; the aperture of the micropyle is seen towards the point of the funnel. This view is semidiagrammatic, and the fine canals passing through the membrane are re- presented fewer and wider than they are in nature. The diameter of the whole ovum was about ±" ; the thickness of the external membrane ^^' ; the width of the base of the funnel about T|5// ; the depth of the funnel ^" ; the diameter of the micro- pyle aperture at the apex 5^5". c. Small portion of the membrane at the apex of the funnel containing the aperture of the micropyle pressed flat, magnified 500 diameters; from the trout's egg. D. A similar portion of the membrane magnified 1000 diameters. The lumen of the canals is seen, and an indication of hexagonal division of the spaces between them, represented somewhat too distinctly in the figure. the existenc6 pf ,tfre •rnuTOpyle " itf tl ie*0va/ o * several fishes ; and though I have not yet been so fortunate as to perceive the sperma- tozoa actually passing into the ovum through this aperture, the accuracy of Ransom's obser- vations on this as well as on other points leave little doubt as to the fact stated by him. The micropyle in the Gasterosteus, as de- scribed by Ransom and observed by myself, • is a considerable funnel-shaped depression in the outer membrane, which projects inwards on the granular substance of the yolk, so as to indent this layer to some depth, and pro- bably to reach near to the germinal vesicle, which lies imbedded within the germinal layer. The inner narrow end of the funnel terminates in a distinct rounded or elliptical mark, with a fine but distinct line bounding it, which has all the appearance of a foramen, and which is either an open passage or one which is closed only by an extremely delicate structure. The funnel-shaped depression leading to the micropyle may be easily seen on the surface of the egg of the salmon or trout when slightly dried of the adhering moisture, and is of such a size that it may be perceived with the naked eye or with a lens of low magnifying power. In order to perceive the micropyle itself, how- ever, or pore in the point of the funnel, it is necessary to remove from the egg that portion of the dotted shell membrane containing the funnel; and having freed it from the adherent granules of the yolk-substance by careful wash- ing, for which Ransom has recommended a solution of acetate of potash, this part of it may be viewed under pressure with great ease with a magnifying power of 200 or 300 diame- ters. The porous structure of the membrane is then seen to continue very nearly up to the margin of the micropyle. This last has a diameter of from 3^00" to ^oW* The ap- pearance of a double outline surrounding the micropyle proceeds from the circumstance that, in looking through the funnel we see at once two portions of the narrowing wall of the passage of different widths. In Ransom's experiments, very soon after spermatic fluid was placed in the water round the ovum of the Stickleback, several of the spermatozoa were perceived to pass in at the micropyle ; and immediately upon this water was imbibed, and the space named the respira- tory chamber was formed between the yolk surface and the external membrane; a change which in this fish did not take place in the unfecundated ova, but which in some others occurs without impregnation. It is from this fact apparently that Ransom is inclined to the opinion that the micropyle may be closed by a very delicate membrane, which in fecundation is removed or broken through by the entrance of the spermatozoa; but with regard to this point there is still some uncer- tainty. The germinal vesicle previous to its disappearance is imbedded below the super- ficial layer of yolk-substance in a stratum of granular matter ; and Ransom conceives that at the time of the rupture of the vesicle, this ^ranular matter being mingled with the con- [H 3] [J02] OVUM. tears of ike vesicle,. the more immediately germinal part of the egg is formed from the mixture of the two. However this may be, it seems not improbable, from the observations now referred to, that the spermatozoa are conveyed directly to the germinal part of the egg by the funnel of the micropyle. I shall afterwards have to state the more numerous instances in which, following its first discovery by J. Miiller in the Holo- thuria, a micropyle has been detected in the ova of Invertebrate animals ; and I may at- tempt to show the great importance of this aperture in connection with fecundation in ova with thick external coverings to which the spermatic substance does not gain access till the later periods of their formation. The ac- companying figures of the micropyle in the Stickleback will give a sufficiently clear view of this remarkable structure. At present it may be permitted to remark that, if we consider the size of this aperture, and the ease with which it may be found in the ova of fishes by an observer whose at- tention has been called to its existence, to- gether with the fact of its having been so long overlooked previously, there is much ground for caution as to negative statements as to the existence of a similar aperture in the ova of other animals. I have already made al- lusion to this subject in the previous sections, in which I have stated that Dr. Ransom has expressed to me his firm conviction, founded on observations, that the micropyle exists also in the ova of Batrachia. At the same time it is quite probable that such an aperture may only exist or be required for the admission of the spermatozoa when fecundation is of late oc- currence, and when the covering membrane of the ovum is so dense as to resist the pene- tration of the spermatozoa through its solid substance. It is right also to mention that the exist- ence of this aperture, or rather the funnel lead- ing to it, did not entirely escape the observa- tion of preceding physiologists. The accurate Von Baer, in his work on the development of Fishes*, has described in the Bream (Cy- prinus blicca) a funnel-shaped depression of the external membrane, which reached nearly to the surface of the germ ; and he ob- served that this funnel was effaced as soon as the imbibition of water took place. He considered this aperture as most probably owing to the escape of the germinal vesicle from the surface of the yolk and through the coverings of the ovum, "in the same manner as he had described in the frogf, and did not therefore conceive it to serve any immediate purpose in connection with the introduction of the spermatozoa. Dr. Ransom has ob- served that the effacement of the funnel which he had seen in the Stickleback is not inva- riably the consequence of fecundation in the Fish's ovum; for in the salmon and trout * Entwickelungsgeschichte der Fische, Leipzig1, 1835, p. 9. figs. 1. and 2. t De Ovi Mammal. &c., pi. xxv. Fig. 69*. Development of the ova of Gasterosteus. A. B. c. D. Four ova of the Stickleback in the earlier stages of their development within their ovisacs. In that figured at A, which is the earliest, ^" in diam., the germinal vesicle placed near the cen- tre has scarcely any perceptible membrane or wall, hut resembles a gelatinous mass in which the small number of maculae are developed : there is as yet no yolk, but only a slightly turbid fluid substance filling the space between the ovisac and the ger- minal vesicle: delicate epithelial cells project from the inner surface of the ovisac. In B. ^y the maculse have increased in number, the germinal vesicle, as well as all the other parts, has increased in size, the fine granules of the yolk sub- stance have begun to be deposited towards the periphery, but there is as yet no vitelline mem- brane. The wall of the ovisac is now more distinct, and besides the internal cells, there are seen on the exterior the nuclei of external flattened cells. In c. -fig" the maculai have become more numerous and distinct; the yolk granules are more opaque and in greater quantity, and the mass of the j-olk more circumscribed, a clear space now intervening between it and the wall of the ovisac. OVUM. [103] In D. TJ5", although the number of maculae has greatly increased by endogenous multiplication, the germinal vesicle has not now undergone an enlarge- ment proportional to that of other parts of the egg and ovisac : the granules of the yolk, especially to- wards the surface, are much increased, and a narrow clear marginal space on the surface now indicates the commencement of the formation of a zona or vitelline membrane. This appearance ia also slightly perceptible in fig. c. The "dimensions of the several parts in these dif- ferent specimens were as follows : A. B. C. D. Ovisac - - -0025 -004 -0056 -007 Yolk — — -0042 -005 Germinal vesicle - -001 -0016 -0025 -0026 Maculae - - -00015 -00018 -00025 -0003 he found the funnel-shaped aperture to re- main for some time after the completion of fecundation, and in none of the fishes he has observed does he conceive the aperture of the micropyle to be closed. The ova of osseous fishes appear to take their origin within the rudimentary follicles or ovisacs of the ovary mueh in the same manner as those of the Batrachia. The ear- liest part of the ovum that can be distinctly seen within the follicle is a vesicle of about half the diameter of the primitive follicle it- self. A little later this vesicle is seen to be surrounded with a dear, jelly-like substance, in which some small dark granules are depo- sited chiefly towards the surface of the vesi- cle. There is as yet no enclosing membrane, but the follicle is seen to be lined by a layer of extremely delicate hyaline ceils, often dif- ficultly perceptible. The earliest recognisable part of the ovum, therefore, is the germinal vesicle ; which, as in other animals, has soon deposited round it the clear gelatinous base- ment-substance of the yolk, in which the opaque yolk granules soon make their appear- ance. There is not at first any vitelline or other membrane enclosing the primitive parts of the egg, and indeed it is a considerable time before any such membranes are formed. The deposit of vitelline granules increases ra- pidly, so as to give the yolk considerable opa- city ; afterwards larger globules appear, and seem to increase by endogenous multiplica- tion. * The oil globules are at first small, and equally diffused through the whole yolk ; it is only in the later stages of for- mation that they unite into fewer and larger globules.f The granular or primitive yolk- substance continues to surround more imme- diately the germinal vesicle till the period when this vesicle is ruptured, and is probably spread over the germinal disc of the egg. Si- milar granules also occupy, however, in a layer the surface of this part of the egg pre- vious to the rupture of the germinal vesicle ; so that it is not probable that the germinal disc owes its origin, as Coste states^:, entirely to the effusion of the contents of the germinal vesicle. * Lereboullet, loc. cit. t Retzius, loc. cit. j Hist. ge'n. et part, du Develop?, des Corps organ, torn. i. The ovum receives its firm porous mem- brane while within the ovarian capsule, but only in the latter part of the time of its forma- tion. This membrane lies very close to the inside of the ovisac, is at first comparatively thin and destitute of apparent structure, and gradually increases in thickness towards the time of its approach to maturity. At the same time a remarkably thin pellicle may be distinguished close to the surface of the granular yolk-substance, scarcely meriting the name of membrane. As already remarked, it is difficult to determine what is the true homo- logical signification of these membranes. The inner one might by some be regarded as a re- presentative of the zona pellucida, or a conso- lidated pellicle on the surface of the yolk, though it must be admitted that Ransom's ob- servation, that it follows the segmentation, is opposed to this view, and makes it more probable that it is only a part of the yolk itself. The origin of the external porous membrane I am inclined to connect rather with the interior of the ovarian follicle ; but whether by exudation from it, or by amalga- mation of the innermost layer of epithelial cells of the follicle, I have not yet been able to determine. I am inclined to regard the latter as most probable, and that this is the true vitelline membrane. The manner in which the micropyle takes its origin has not yet been ascertained. It will afterwards be shown, that in a consider- able proportion of those invertebrate animals in which this aperture in the egg coverings is found, it has existed from a very early period, and proceeds from the remains of the pedicle by which the ovum is originally con- nected with the ovarian substance. Such a pediculated connection has certainly not yet been observed by most of those who have in- vestigated the ovarian ovum of fishes.* Rathke, indeed, observed the appearance of the remains of a pedicle in the detached ova of the Blennius viviparus -j- ; according to Ransom the micropyle in the Pike is not a depression, but projects from the surface like a trumpet-shaped process; and in the earliest stage of development of the ovarian ovum of Trigla hirundo, according to Ley- dig J, the shape is somewhat pyriform or pediculated, in the same manner as in some of the invertebrate animals. On the other hand, Ransom expressly states that he has never been able to observe the slightest connection in Gasterosteus be- tween the pedicle of the ovum by which it is attached to the ovary, and the mi- cropyle. This aperture he says is always situated at that side of the ovum towards which the germinal vesicle and the germinal disc are placed ; but these parts have no regular connection with the pedicle. The pe- * The pedicle here spoken of is not that of the ovarian capsule containing the ovum, but of the ovum itself within the capsule, \ Abhandlung. zur Entwick. part. ii. p. 4. t MUller's Archiv. for 1854, p. 376. fig. 6. OVUM. dicle, he affirms consists only of the ovarian structure, and of no part of the membranes of the ovum. From his observations on Gaster- osteus, in which the projecting bodies from the porous or outer membrane in the vicinity of the micropyle enable this part to be easily recognised, he feels confident that if any pediculated connection had existed it could hardly have escaped notice. When the ovarian ovum has attained ma- turity it falls into the cavity of the ovary, or that which may be regarded as ovary and oviduct united, by the rupture of the ovarian capsule in which it is contained. The walls of the ovi-capsules have by this time become extremely thin ; but according to Von Baer a small stigma or non-vascular mark may be dis- tinguished where the rupture takes place. After the ova have fallen into the common cavity they are surrounded by a considerable amount of secreted albuminous matter, by which in some fishes the ova are covered when excluded. In some this albuminous se- cretion serves to unite the spawn in chains or networks. In other fishes the ova are covered externally with villous projections ; but the manner in which these are formed has not yet, so far as I am aware, been observed. One of the most remarkable, but as yet quite unexplained, varieties in the external coverings of the ovum in one of the osseous fishes, is that discovered and recently de- scribed by Ernst Hackel, as occurring in the family of Scomberesoces** This consists in the formation, in the space between the sur- face of the yolk and the vitelline membrane (that is, the porous membrane), of a layer of long and very distinct fibres, which are wound somewhat spirally, but irregularly, over the surface of the yolk. Hackel has traced the gradual formation of these in fresh specimens of Belone from points on the surface of the yolk-substance; and in other genera he has observed several varieties in the forms of the fibres. They are on an average about -S-^Q-Q" thick, and long enough to surround the egg several times ; and they appear to resemble the fibres of the elastic yellow tissue more than any other animal substance, but do not entirely agree with them. In the meantime we must suspend our judgment as to this very extraordi- nary addition to the surface of the ovum until farther observations shall have been made as to their distribution in various fishes or other animals, and as to their relation to the deve- lopment of the embryo, f * Muller's Archiv. 1855, p. 23. See plates IV. andV. f Some time after the above was in the hands of the printer, I received the first and second parts of the seventh volume of the Zeitsch. fur Wissen. Zool., containing a notice of the discovery of the micropyle in the Salmo salar, and S. fario, by Professor Bruch of Basle. The observations leading to this discovery were made in the winter of 1854-5 ; and it is right to state here, that Dr. Ransom's dis- covery of the micropyle in the gasterosteus, which •was communicated to the Royal Society on the 23rd of November, 1854, was made in the months of June and July previous; and these observations had been Invertebrate Animals. — The ova of Inverte brata may be considered under two princi- pal divisions, according as they present more of the large-celled or of the finely granular yolk-substance. The ova of the first kind are usually of a larger size ; they possess a larger germinal vesicle, and often a divided or multiple macula ; and the process of seg- mentation in them is either partial, that is, limited to one part of the surface of the yolk, or it occurs in a different manner on the upper and lower sides of the ovum. In these there is, in fact, nutritive as well as formative yolk. In the other division of animals the yolk is finally molecular, or is mainly composed of smaller granules, and is chiefly of the formative kind ; segmentation usually involves the whole yolk, or if not so, is very nearly complete : the germinal vesicle is generally clear, and the macula most frequently single, and well marked. It is true that the form and struc- ture of the ova of Invertebrata presents many and considerable varieties, as might indeed be expected among animals of such diversity of organisation as belongs to the great divisions of the Radiata, Articulata, and Mollusca ; but still it is to be observed that as a greater degree of simplicity exists in the form and structure of the primordial elements than in the more developed textures and organs of ani- mals, so also we find that much closer analogies may be traced among these elements in the lowest classes of the animal kingdom. We meet, therefore, with little difficulty, even in the most diverse tribes of the Invertebrate animals in tracing the correspondence of the essential parts of the ovum; and we are enabled also to trace a more close analogy between these and the corresponding parts in the Vertebrata than might have been expected. We are there- fore warranted in applying to them similar designations ; and we have daily increasing reason to trust to observations made on the ovology of the lower animals as the means of extending the knowledge of the reproductive functions in Vertebrata and in Man. Thus the recent discovery of the micropyle aperture in some animals, and the certain and clear ob- servation of the penetration of the sperma- communicated to Professor Sharpey and myself in August and September. In the beginning of January, 1855, Dr. Ransom informed me by letter of his having found the micropyle also in the Trout, and a few days later in the Salmon. I then saw the micropyle in the ova of both of these fishes ; and I have since examined it minutely in the Stickleback, and have confirmed in every particular Dr. Ransom's statements. The existence of the micropyle in these Vertebrate animals has thus been established by several independent observations ; and I believe that no one who uses the proper means can fail to detect it in these and other fishes. Professor Bruch's ob- servations were chiefly made on the ova after im- pregnation, which may explain the reason of his having failed to perceive the connection pointed out between this aperture and the depression in the centre of the germ disc. Bruch was like myself unsuccessful in perceiving the entrance of sperma- tozoa by the micropyle. His measurement of the micropyle in the Salmon and Trout does not agree with mine, making it much smaller. OVUM. [105] tozoa into the ovum in others, suggest novel and more general and extended views of the process of fecundation, and while they add certainty to the more limited observations of the same kind made upon animals higher in the scale, tend to prevent the adoption of partial views in regard to these functions of the animal economy. It is principally among the more highly or- ganised Invertebrata that we meet with that form of ovum in which the nutritive is com- bined in considerable quantity with the forma- tive yolk, and in which segmentation is partial, such as the Cephalopoda, Insecta, Arachnida, Myriapoda, Crustacea, and some of the Arti- culate Worms. In by far the greater number of the Mollusca, such as Gasteropoda and Acephala, the ova belong to the smaller kind with more or less complete segmentation, as also in most of the Annelida, as Hirudinea and Lumbricina, the Nematoid, Cestoid and Trematode worms, with the Planariae, the Rotifera, Echinodermata, Bryozoa, Acalephae and Polypina. I now proceed to give a short statement of the principal facts that have been ascertained as to the structure of the ovum in these ani- mals, and to state some details with regard to some of those which are either best known or which present phenomena of the greatest interest. 1 st. Large-yolked Ova with partial Cleavage. Cephalopoda. — The ova of this class of ani- mals have already been referred to in connec- tion with those of birds, scaly reptiles, and cartilaginous fishes, to which they present in some respects a greater analogy than to those of almost any of the Invertebrata. The con- siderable size of the germinal vesicle with its multiple maculae, the large mass of the coloured yolk (nutritive), composed of conglomerated masses of yolk corpuscles, and the very limited extent of the process of segmentation, which affects only a round disc of the germinal part of the egg, are all characters in which the ova of the Cephalopoda, at least the Sepia and Loligo, which have been fully examined, are ascertained to be similar to those of the large- yolked group. We owe the most of our knowledge of the ova of this class and their development to Kolliker's interesting treatise, published in 1844.* The ova of the Sepia are deposited singly, but are attached in numbers close together by pedicles to the stalks of Algse and other marine productions. Those of Loligo arc arranged in sm?ll masses, in which a number are enclosed in a general bag or covering of gelatinous matter, which is at- tached along with others of the same kind by means of pedicles. I have found those of Sepiola also thus enclosed in small pyriform capsules. The ovum of Cephalopoda possesses a firm laminated external covering or chorion, which in some is darkened on the surface by the colouring matter or ink, in others is trans- * Entwickelungs-gesch. der Cephalopoden, 4to. Zurich, 1814. parent and' colourless. Immediately within this outer membrane is situated a structureless vitelline membrane, containing the mass of yolk-substance, which is separated from the membrane by a slight interval. It appears to be ascertained that the chorion is formed by superposition on the surface of the ovum dur- ing its descent through the oviduct. In the ovary the ova are contained in slender capsules, attached to the rest of the ovary by narrow pedicles. When ripe the ova escape from the capsules, in some species by an ir- regular laceration, in others by a more regular and defined opening, and, falling into the cavity of the ovary, pass thence into the oviduct, through which they are finally excluded. Fe- cundation is believed to occur soon after the escape of the ova from their ovicapsules or in the earlier part of their descent through the oviduct ; but this process has not, so far as I am aware, been directly observed. The ova of the common Sepia officinalis have an oval form, one end being much nar- rower than the other. It is at this the pointed extremity or narrow pole of the egg that the germinal vesicle is situated, while the egg is in the ovary, close under the vitelline membrane; and it is at this part also that, at a subsequent period, the process of segmentation and the first formation of the embryo take place. The narrow end is therefore the germinal pole. This extremity of the egg is always turned to the opposite side from the pedicle of the cap- sule, which is attached to the middle of the blunt or wider end. One of the most remarkable peculiarities in these ova, is the extraordinary change which the outer part of the yolk and the vitelline membrane undergo during the greater part of the time occupied by the growth of the ovum in the ovary. This change, of which the appearance had been known to some previous observers, was first accurately- described and explained by Kolliker. From his observations it appears that at first the ovarian ova are quite smooth on the surface, and that at the time of complete ma- turity of the ovum, or after its escape from the ovary, the vitelline membrane and surface of the yolk are also quite smooth ; but that in the intervening time, that is, during the greater part of the period of its growth, the surface of the yolk is indented or marked with peculiar grooves, into which folds of the vitel- line membrane pass so as to line them to the bottom, somewhat after the manner in which the pia mater descends into the sulci of the brain, but without the same convoluted form. This has been represented by Kolliker in the Sepia, and 1 have observed it in this genus, and have con- firmed in every particular that author's state- ments as to this change. It appears that at first these inflections of the yolk and membrane begin as longitudinal folds, extend- ing between the wide and narrow poles of the ovum, and, gradually increasing, become at last so deep as almost to meet each other in the interior of the yolk. Subsequently they are traversed by more numerous depressions. [106] OVUM. which subdivide them ; and as these cross folds are formed the longitudinal ones beome gradu- ally shallower. The surface of the egg then presents the reticulated appearance which is shown in fig. 70.* On making a section through such an egg, hardened in alcohol or any other suitable reagent, it is easy to per- ceive that the ovicapsule takes no part in the inflections, but that they consist entirely in the grooving of the yolk, and the corresponding bending into the grooves of the vitelline mem- brane. This state is maintained till the ovum is approaching maturity, when the depth of the grooves or folds speedily diminishes; and these come at last to be completely effaced in those ova which have left the ovicapsule. In Loligo, it is stated by Kolliker, there are only the longitudinal folds. No satisfactory opinion has been offered as to the cause of this peculiar structure. Fig. 70 *. Ova of the Sepia. (From Kolliker.') A. Three ovarian ova of the Sepia in somewhat different stages of advancement attached by their pedicles to the ovary, and represented several times magnified. They all show the reticulated mark- ings on the surface produced by the folding in of the vitelline membrane ; g, the place of the germi- nal vesicle and possibly also of a micropyle at the Bonall pole of the egg, in which segmentation after- wards occurs. B. Direct view of this germinal pole of one of the ova, showing the absence of the folds towards the centre in which the germinal vesicle is situated. c. Cross section of one of the ova, showing at o the unfolded or smooth ovarian capsule, and at v m the folded vitelline membrane. Towards the narrow pole of the ovum, the folds now described become less marked ; and they are entirely absent just at the pole itself, so that the germinal vesicle may be seen in the smooth space which is left between them. At this place I had some expectation to find an aperture of the nature of a micropyle ; and I accordingly sought for it in some specimens of the ovarian ova of Sepia which I had pre- served in alcohol, but without success, per- haps on account of the opacity produced in the membranes by the alcohol, and the adhe- sion of the yolk substance to them. Professor Kolliker has since informed me that he believes the micropyle to exist in these ova, which I think extremely probable. The germinal vesicle, according to this ob- server, remains entire and visible till the ova are mature, as may be seen by the examination of specimens hardened in alcohol. It dis- appears just about the time of the ova leaving the ovarian capsule ; but in several instances he found it still remaining in ova that were already free. It was always gone in those ova which had regained the smoothness of their exterior. The yolk-substance of the mature ova con- sists entirely, excepting immediately at the seat of the germinal disc, of corpuscles some- what similar to the vitelline tablets of the Frog's egg. At an earlier period there are heaps of fine granules of the same size, from which the corpuscles are therefore probably formed. In the earliest stage the vitelline substance is entirely composed of fine molecules — the pri- mitive yolk — which appear to be formed in the same manner as in other animals. The Cephalopoda furnish a remarkable ex- ample among the Invertebrata of a very limited or partial segmentation. This process, upon the detailed description of which I will not enter here, usually commences in a spot either in or more frequently near to the germinal pole, by the formation of the primitive groove which extends across the disc. The forma- tion of the second groove, which crosses the first, the production of other radiating grooves, the separation of annular sets of segments from the periphery, and the suc- cessive steps of the process which follow, are probably determined by the same circum- stances which have been referred to as re- lated to this phenomenon in the cicatricula of the Bird's egg. Gasteropoda. — In the greater number, if not almost all, of the remaining Mollusca, the ova differ greatly from those of the Cephalo- poda, and approach more nearly to those I have classed under the groups possessing the small or middle sized yolk, which is princi- pally or entirely formative, and which under- goes a more or less complete segmentation.* In the Pteropoda and in those of gasteropodous Mollusca, which have the male and fe- male organs in the same individual, there is a remarkable combination of the ovary and testis in a single hermaphrodite organ, usually * The genus Sagitta, among the Pteropoda, is, however, probably an exception to this statement, as in it, according to Darwin, the embryonal part of the yolk is distinct from the rest, or rather covers it like a ring. U07J jenital Organs of Phyllirhoe bucephalum, one of the Hermaphrodite Gasteropoda. Gegenbaur.*) (From H.MiiUerand A. The compound or hermaphrodite organs dissected out and represented several times magnified ; o t, the two productive organs each composed of ovigerous and seminiferous parts ; v d, the common excretory ducts for both kinds of organ ; v st the seminal vesicle ; «, the uterus ; p, a part of the penis ; c, the common external vent. B. One of the lobes of the common productive organ laid open and more highly magnified. Towards the surface o o, the ova are seen in different stages of development in the ovarian stroma ; in the interior t t, the substance of the testis with spermatic cells and spermatozoa in various degrees of advancement ; some of the filaments being very long ; v d, the common excretory duct for ova and spermatozoa. enclosed in the liver, the nature of which was for along time involved in obscurity, and occa- sioned much doubt and difficulty to naturalists. The explanation of this peculiar structure we owe first to H. Meckel*, and Leuckart-f- ; and more recently H. Meckel and Gegenbaur have described this organ particularly in one of the heteropodous Mollusca, viz. Phyllirrhoe buce- phalum.J The outer part of this curious organ constitutes the ovary, the inner the testis ; and the products of these respective organs, in leaving the seat of their first formation, pass together into an inner common cavity, and thence downwards in the excretory duct. There is, therefore, a common outlet for both. The ova and spermatozoa most frequently pass out at different times ; but occasionally both these reproductive elements are seen to- gether in the passages. It seems probable therefore that they in general meet for im- pregnation only in 'the lower part of the pas- sages ; but this apparently is not yet fully de- termined, and the modes of union may be * Miiller's Archiv. for 1844, p. 483., see plates xiv. and xv. t Zur Morphologic und Anatomie der Geschlechts Organ. 1847, p. 128. I Zeitsch. fur Wissen. Zool. vol. v. p. 355. pi. xix. various in different genera or families. At all events, the primitive ova and spermatozoa seem to come into contact with each other previous to the addition of the enveloping membrane. * The ova of the Mollusca are in general of small size. The yolk consists of a viscid al- buminous substance, containing suspended in it minute granules, and a variable quantity of coloured oil globules. The germinal vesicle is proportionally of considerable size ; and the macula is distinct and granular. Leuekart*f* states that he and Nordmann have ascertained that in Lymneus, the first part of the ovum which is formed is the germinal vesicle, that the yolk-substance begins as a clear trans- parent albuminous matter surrounding the germinal vesicle, and, as we have seen in various other animals, the granular yolk matter is gradually deposited in this clearer part of the vitelline substance, occupying at first princi- * The hermaphrodite gland exists in the Ptero- poda, Apneusta, Nudibranchia, Infero-branchia, Tec- tibranchia, and Pulmonata. The Mollusca which have separate sexual organs belong chiefly to the orders Cyclobranchia, Scutibranchia,Tubulibranchia, and Cirnbranchia, some Heteropoda, Pectinibranchia, and operculate Pulmonata or Cydostoma. t Article Zeugnng, p. 800. [108] OVUM. pally its outer part. The vitelline membrane does not exist at first, but seems to be formed at a later period by the consolidation of an external layer of the primitive yolk substance. The time of the disappearance of the ger- minal vesicle has not been determined in many of these Mollusca. Previous to seg- mentation a phenomenon occurs, which has now been observed in a large number of ani- mals, but which first attracted special atten- tion in the gasteropodous Mollusca; viz., the separation of one or more clear hyaline liquid globules of considerable size from the surface of the yolk substance, into the space be- tween it and the vitelline membrane. This was first observed by Dumortier*, and de- scribed by Pouchetf, by Van Beneden in the Aplysia J, by Nordmann in Tergipes Ed- wardsii $, by C. Vogt in Actoeon || , and by various others. A precisely similar phenome- non has also been observed in some of the Vertebrata, as in Mammalia by Wharton Jones, Barry, and Bischoff, and in Batrachia by Newport. But though this separation of one or more hyaline globules from the yolk- substance at the time of segmentation appears to be a very general accompaniment of that process, it must be confessed that its import, either in connection with fecundation or de- velopment, has not yet been ascertained. Acephala. — In Acephalous Mollusca the ova are generally of small size, the yolk-sub- stance principally finely granular, the germinal vesicle clear, with a distinct macula, which last not unfrequently presents the form of a double or elongated biscuit-shaped particle. The vitelline membrane is distinct and possesses considerable strength ; and there is generally a considerable space occupied by clear fluid between it and the surface of the yolk. The most interesting feature of the ova of these Mollusca is the funnel-shaped aperture which most of them possess, leading through the vitelline or external membrane into the space occupied by the yolk. This aperture, styled micropyle by J. Miiller in the Ho- lothuria, the first instance in which it was discovered, in 18591F, was observed in the ova of Unio and Anodonta by Leuckart ** and Keber. ff The latter author supposed that he had observed the penetration of a spermatozoon into the ovum through this aperture, and has described with great form- ality and minuteness all the phenomena which he conceived were related to that process. Although Keber was correct in asserting the existence of the micropyle in these Mollusks, * Embryol. des Mollusques, in Annal. des Scien. Nat. for 1837, p. 136. f Id. lib. for 1838, vol. x. p. 63. See also Pou- chet's further observations in his work, Theorie positive de 1'Ovulation spontanee, pi. xvi. J Annal. des Scien. Nat. 1841, p. 126. § Id. lib. 1846, p. 147. || Sur PEmbryol. des Mollusques Gasteropodes, id. lib. 1846, p. 33. f Archiv. 1852, p. 19. "* Article Zeugung, p. 801, Ann. 1853. ft De Introitu spermatozoorum in ovula, &c. Konigsberg, 4to. 1853. Fig. 112 Ova of Unio in different stages of development. (A. B. C. and D., from Hassling ; E. from Keber.} A. The early stage of the ovum, when the ger- minal vesicle alone is distinguishable lying in a bulging part of the ovarian substance. B. The same somewhat more advanced; the ovicapsule and vitelline membrane have assumed the pediculated form, and the yolk granules sur- round the germinal vesicle. c. The ovum now enlarged and spherical in form, the yolk granules increased in quantity, and the pedicle narrowed so as to form a short micropyle tube ; s, the small body taken by Keber for a sper- matozoon, existing long previous to the occurrence of fecundation. D. The ovum, &c. at a later stage ; g, the ger- minal vesicle ; v, the yolk ; t/, the separated portion of the yolk ; s, as in c. now enlarged. E. A nearly similar stage of the ovum as figured by Keber. Some of the contents of the separated portion of the yolk are escaping through the micro- pyle aperture ; s, Keber's alleged spermatozoon. it appears that the body described by him as spermatozoon cannot have been of that nature, seeing that it has been proved by other observers that the appearance on which Keber's supposition was founded existed long before fecundation, and remained long after the commencement of embryonic formation in the same condition.* The existence of a similar aperture or micro- pyle in several other Acephalous Mollusca has been ascertained by the recent investiga- tions of various authors ; but the actual en- trance of the spermatozoa by the aperture, has not, so far as I aware, been satisfactorily observed. There seem, however, to be suffi- cient grounds for believing that in the Ace- phala, as in other animals in which it is found, the micropyle is immediately related to the process of impregnation, by affording a ready access of the spermatozoa to the yolk through the more resistent membranes of the ovum. The accompanying figures from Keber and his critic Hessling give a sufficiently clear view of * Hessling, in Zeitsch. fiirWissensch. Zool., 1854, vol. v. p. 380. ; and Bischoff, "Wiederlegung des von Dr. Keber bei den Naiaden, &c. Giessen, 4to. 1854. OVUM. [109] the nature of this structure in the mature ovum of Anodonta. In this family of Mollusca the micropyle forms a small but very apparent funnel-shaped projection from the surface of the outer mem- brane ; and its hollow nature may easily be ascertained by the fact that the fluid and granular yolk-substance may be forced through it from within. The yolk ball is placed ex- centrically within the vitelline membrane, the inner surface of which it touches just at the place where the micropyle is situated. From a variety of observations, it has been Fig. 73*. Structure and Fonnation of Ova in Acephala. (From Lecaze Duthiers.} a. Portion of the ovary with three pediculated ovicapsules and contained ova from Cardium rusti- cum, magnified 400 diameters ; the micropyle is afterwards formed at the place where the pedicles are detached from the secreting coeca of the ovary. b. Unripe ovum of Spondylus gaederopus magni- fied 170 diameters, showing the remains of the cap- sule at the upper part, and the projection of the vitelline membrane at the same place where the micropyle is situated. c. Ripe ovum of the same burst by pressure, showing the escape of some yolk granules through the micropyle and into the space between the yolk and the outer membrane. In^this and the previous figure the double state of the macula is represented. shown that the micropyle of the Acephalous Mollusca owes its origin to the early pediculated attachment of the ovum. This has been fully brought out by the observations of Hessling in Unio and Anodonta, of Leydig in Venus, and of Lecaze Duthiers in Cardium and some other genera.* From these observations it appears that the ova first arise in the ova- rian stroma by the formation of the ger- minal vesicles, as in most other animals, each vesicle possessing a distinct single macula. These vesicles come very soon to be surrounded by some of the primitive or finely granu- lar yolk, which gradually increases in quantity. These parts are from a very early period en- closed by a membrane which may be regarded as vitelline, but which is differently disposed from that in any of the animals previously re- ferred to ; for, instead of having a regular and complete spheroidal or vesicular form, this membrane is elongated at one part into a pedicle, so as to give the whole of the early ova a pyriform shape, and so as to attach them to the ovarian substance by the pediculated parts of the vitelline membrane. In Venus de- Fig. 74*. Ovarian ova of Venus decussata. (From Leydig.') a. A group of five ova in their earliest stage projecting from the ovary in their pediculated capsules : the germinal vesicles with single macula, the vitelline granules, vitelline membrane, and ovicapsule are all distinct. b. Two ovicapsules within which at a more ad- vanced stage the ova have become detached from their pedicles, the remains of which at the upper ends of the ova form the micropyle. A considerable amount of albumen has been deposited between the ovum and the ovicapsule. * Ann*! des Scien. Nat 1854, ii. p. 155. [no] OVUM. cussata, according to Leydig*, the ova are ar- ranged in aggregated pediculated groups, from which it seems probable that they are originally produced in numbers by the multiplication or division of multiple germs, somewhat in the same manner as will afterwards be stated to have been observed by Meissner among the Gordian Nematoid Worms. An albuminous layer is afterwards formed externally, and may be instrumental at last, from its increasing thickness, in separating the ovum from its pe- diculated attachment to the ovary. There seems therefore to be little doubt that in these Mollusca, and in a certain number of other Invertebrate animals in which the micropyle has been observed, this apparatus is produced by the remains of an original or early ovarian pedicle. In the Unio and Anodonta it is certainly not formed by the peculiar process of development from within the ovum, which has been elaborately described by Keber.-j* It will afterwards be shown, however, as in- deed may be concluded from what has already been stated in regard to osseous fishes, that in other animals the micropyle may arise in other modes and without the early existence of the pedicle now described. When the ova are detached by the rupture of the pedicle in the Acephala, they lie, in different stages of advancement, but all pro- vided with the micropyle, in the general ovarian cavity. The coverings of the Acephalous ovum appear to be composed at least of two layers, of which the inner may per- haps be looked upon as the vitelline mem- brane, the outer as a chorion ; but sufficient data have not yet been furnished to determine the homological rank of these membranes. The early connection, in a pediculated form, with the ovarian stroma might point to a different view of their nature. Leydig states that while in Unio and Anodonta the albu- men is deposited within the membranes, in Venus it is added externally. The micropyle appears to be closed previous to the com- mencement of embryonic development. Arthropoda. — The ova of Articulate animals might with most propriety be classed with the large-yolked group, at least as regards the ova of Insecta, Arachnida, and the higher Crustacea. In addition to the germinal vesicle and finely granular yolk-substance, they all contain a large proportion of clear or oil glo- bules of considerable size ; and the process of segmentation is generally limited to a small portion of the yolk surface. The ova of .these three classes present, however, many subordinate differences in their structure and mode of production, which renders it neces* sary to give a short separate account of them in this place. Insecta. — The ova of insects are more especially distinguished by the extraordinary varieties of their external form and appearance. These varieties affect, however, principally, or depend upon modifications of the external M tiller's Archiv. 1854, p. 320. Hessling and Bischoff, loc. cit covering, chorion or shell-membrane, as it has been called. They differ also from those of most other animals in a frequent departure from the regular symmetrical form. Some are nearly hemispherical, others more oval ; many are somewhat bent in an antero-posterior direction *; many present the most curious elevations and irregularities on their external surface — reticulated ridges or fringes, and de- pressions, tubercles, hairs or spines, or other long processes, sometimes single, at other times in numbers. These modifications of the external coverings of the eggs of Insects appear to have reference chiefly to the protection of the ova from the effects of external injury, and to serve various mechani- cal purposes connected with their deposition and attachment ; but they are not, in most at least, attended with any important varieties in the internal structure, which, on the whole, presents considerable uniformity throughout the whole class. The ova of all insects, we shall afterwards see, are provided with one or more apertures corresponding to the micro- pyle. t All recent observers agree that, in the ova of Insects, in addition to the external shell- covering, there is a delicate transparent vitel- line membrane. The germinal vesicle is of pro- portionately large size. Its macula is at first single ; but in the course of the growth of the ovum it becomes multiple, or diffused as a finely granular or molecular substance throughout the vesicle.f The germinal vesicle is situated in a vitelline or germinal area composed of fine granules, in which without doubt the limited process of segmentation afterwards takes place ; but fuller observations are still much required in regard to the segmentation of the yolk in insects, which has as yet been very rarely seen. The germinal vesicle appears to be burst and diffused at a comparatively early stage of the growth of the egg. The external membrane consists in general of more than one layer of substance. The outer and inner are described as being gene- rally more clear, dense, and homogeneous; the middle one, in some insects at least, pre- senting greater varieties of structure, and not unfrequently being composed of united nu- cleated cells. It is in these several layers of the outer membrane that the micropyle ap- paratus, recently discovered, is situated. The existence of a micropyle in the ova of Insects was first published by Meissner, in September, 1854 £ ; but the discovery appears to have been made simultaneously by Leuckart, who has given a most interesting and elaborate description of this apparatus, and of the minute structure of the membranes, in a great variety of insects, in a memoir recently pub- lished by him.$ Meissner described several varieties of the * This has reference to the position they occupy during their formation in the passages of the female parent. f See R. Wagner's Prodromug Hist. General. I Zeitsch. fur Wissen. Zool. vol. v., p. 272. § Memoir on the Micropyle and Minute Structure, OVUM. [HI] Fig. 75*. tained by that author, were extended over a very large number of Insects. Among nearly a thousand different kinds, he succeeded in de- tecting the existence of the micropyle in not less than two hundred ; and his detailed ob- servations on this apparatus, and the structure of the membranes, extend to one hundred and Fig. 76*. Micropyle in the ovum of Insects. (From Meissner.') a. A portion of the upper pole of the ovum of Musca vomitoria from the Vagina. There are shown in succession the vitelline membrane, chorion and outer envelope, and at the upper part in profile the micropyle aperture situated in the middle of a nipple-like projection of the chorion, and with a number of spermatozoa involved in it. b. Direct view of the upper pole of the ovum of an insect belonging to the Pyralida. The micro- pyle aperture is seen in the centre of the radiated markings of the chorion. micropyle apparatus in the ova of Insects be- longing to the following genera, viz., Musca, Tipula, Culex, Lampyris, Elater, Teleopho- rus, Adela, Pyralida, Tortrix, Euprepia, Li- paris, Pieris, Panorpa, and in more than one species of several of these genera. The same author also observed and described in Musca vomitoria a number of spermatic filaments entangled in the micropyle. Leuckart's observations, which are fuller and more minute than those of Meissner, and differ in some of their results from those ob- &c., of the Ova of Insects, chiefly pupiparous, in Miiller's Archiv. Xos. 1. 2. and 3., February and July, 1855, p. 90., ft seq., with five plates, with 122 figures. There can be no doubt that both of these authors made the independent discovery of this curious structure. Perhaps the priority claimed by Leuckart, may be accorded to him, as he had pre- viously stated the probability of its existence in his article " Zeugung," published in 1852, p. 906. Micropyle of the ovum of Lepidoptera. Leuckart.) (From A. Side view of the upper part of the ovum o Sphinx Populi, showing the micropyle, the radiated markings surrounding it, and the cellular and other structure of the coverings of the ovum. B. More enlarged and direct view of the vicinity of the micropyle in the same. The dotted or punc- tated structure belonging to the chorion is here re- presented. eighty species. This must furnish ample proof of the universality of the existence of the micropyle in this class of animals, when we consider the minuteness of the object and the difficulty of obtaining specimens in a con- dition suitable for the investigation. Leuckart has stated, indeed, that in all instances in which the ova were ripe and favourable for examina- tion, he was enabled to assure himself of the presence of this apparatus. In a certain number of instances, amounting to about a dozen, Leuckart farther found that the spermatozoa adhere to the micropyle, and that a certain number of them pass into the ovum by this aperture. He observed that a [U2] OVUM. Fig. 77*. Ovum and Micropyle of Dipterous Insects. (From Leuckart,) A. Ovum of Melophagus ovinus (Muscida). 1. The entire ovum, presenting at its upper part the adherent mass of spermatozoa close to the micro- pyle. 2. This upper part more highly magnified, showing a section of the micropyle, above which the point of the conical mass of spermatozoa glued together by an albuminous substance is inserted, while externally the filaments float free. 3. The micropyle apertures seen directly from above. B. Side view of the upper part of the ovum of another insect of the same order, showing a single micropyle aperture and the dotted structure of the chorion. small mass, formed of the spermatozoa which have met with the ovum in its descent through the female passage, comes to be lodged in the depression of the micropyle, and is fixed in that situation by a lid or covering of albu- minous matter. It is somewhat remarkable that the greater part of this mass remains for a long time apparently without any change, even when embryonic development has ad- vanced to a considerable extent ; but he as- certained that a few of the spermatozoa be- longing to the mass, usually not more than three or four, really enter the ovum and effect the change of fecundation. We are, however, as yet at a loss to conjecture what farther purpose may be served by the mass of per- sistent spermatozoa near the micropyle. Leuckart has also made the novel and interesting observation, that the depression and aperture of the micropyle become at a later period converted into a deeper funnel, which is connected directly with the mouth of the embryo, and undoubtedly serves, ac- cording to this author, to convey nourishment from without to the embryo. The head of the embryo lies, according to Leuckart and other observers*, in all instances, at that end or pole of the ovum which is uppermost in the oviduct, as may be most easily observed in ova of the cylindrical form, such as those of the common house-fly ; but according to Leuckart, the micropyle is not, as Meissner had stated, always at that end, being some- times at one, sometimes at the other, and oc- casionally at both poles. The provision for the escape of the embryo, however, is usually at the upper or anterior pole, while the lower or hinder pole more generally serves to fix the ovum, as it is often pediculated or other- wise modified in its form in connection with this purpose. In some Insects, as is shown in the accom- panying figure of the ovum in Pulex irritans, the micropyle consists of a number of foramina nearly of uniform size. Ovum of Pulex irritans. (From Leuckart.) A. Entire ovum, magnified, showing the micro- pyle apparatus with a number of foramina at both B. Portion of the chorion with the micropyle foramina, more highly magnified. In a previous part of this article allusion has already been made to the great facility with which the development of the ova of in- sects may be traced, in their successive stages, as they lie in different parts of the tubular ovaries and oviducts. According to the In- teresting observations of R. Wagner f , the upper end of the fine ovarian tubes are filled with a number of germinal vesicles. Wag- ner supposed indeed that these were at first nucleoli or germinal maculae, and that a vesicle was developed round each macula ; but Leuck- art:}: and Stein$ were never able to detect the germinal vesicles before they already possessed the macula. The primitive yolk arises as in most other animals — first, by the collection of a clear substance immediately round the germinal vesicle, and by the subsequent de- posit in this matrix of the fine granules of the vitelline substance ; later still the deli- cate vitelline membrane is formed, perhaps by the consolidation of a film of the primitive yolk-substance. As the ova attain a larger size, each one being situated in the lower part of its compartment * See Kolliker, de prima Insector. Genesi, 4to. Turici, 1842. f Prodromus, Hist. Gener. p. 9., and Beitrage zur Entwickel., &c. p. 42. See fig. 40. Append, of CYCLOP. ANAT. AND PHYSIOL. i Zeugung, p. 803. § Vergleich. Anat. und Physiol. der Insecten, Berlin, 1847. OVUM. [113] Development of the ova of Lepidopterous Insects. (From Hermann Meyer.} b. A small portion of the upper part of the ova- rian tube from the larva of Saturnia Carpini. The entire lines mark the basement membrane of the tube; externally elongated epithelial cells are placed on it ; internally a number of larger and smaller free nuclei are imbedded in an albuminous fluid. «. A similar portion of the ovarian tube from Bombyx Mori more developed. The external epi- thelial cells are visible now only as elongated nuclei ; a part of the internal cells now form a lining to the wall of the tube, while others of a larger size, which have become complete cells, towards the centre, form the primitive ova ; of these last only a few undergo farther development. c. One of the loculi or chambers of the oviduct of Hyponomeuta variabilis. The wall of the tube with its external epithelial nuclei as before, enclos- ing now the entire loculus and the small portions of the adjacent ones represented in the figure. The lower half of the loculus is occupied by the deve- Supp. loped hemispherical ovum in which the several parts, viz. germinal vesicle with macula, yolk and vitelline membrane, are seen. The lining cells of the oviduct are seen to be elongated and modified in structure preparatory to their forming along with the albumen one of the external coverings of the ovum (chorion). In the middle of the upper half of the loculus there are the remains of five aborted primitive ova, d. Section of the coverings of the ovum of Har- pyia vinula, which may be taken as an example of the hemispherical ovum of Lepidopterous insects. of the oviduct, there are to be seen in the in- tervals between the ova numbers of large clear globules or cells, which have been supposed to furnish the materials for the growth of the ovum ; but it appears more probable that these are merely abortive ova or germinal vesicles, which, though at first similar in size and structure to those which have been farther developed, have undergone a retrograde pro- cess, and are ultimately removed by absorp- tion. The production of the chorion or shell membrane does not take place till the ovum has attained nearly its full size. It appears to proceed in part from the consolidation, over the whole surface, of one or more layers of albuminous fluid secreted from the wall of the oviduct. But the observations of Hermann Meyer* have shown, in an in- teresting manner, that a part of the outer membrane is also derived from a conversion into it of the inner cellular or epithelial lining of the oviduct, at the place where it is in closest contact with the surface of the ovum. Many of the varieties in the appearance and structure of the external covering may pro- bably depend on the different modes of deve- lopment of these cells. As to the origin of the micropyle, it does not appear to proceed, as has been supposed by Meissner, from the mere deficiency of these cells in a certain space; and it is not dependent, either, on its pre- ex- istence in the vitelline membrane. On the contrary, according to Leuckart, it is formed in the chorion before it appears in the vitel- line membrane ; and it is not in -any way con- nected with an early pediculated condition of the ovum, which, as is well known, never at any time exists in insects. Before leaving the history of the ovum in this class, it may be proper to make the fol- lowing addition to what was stated in an earlier part of the article in reference to the remarkable modification of the reproductive process, by which, in the Aphides and several other insects, many individuals are produced without the formation of true ova, or the con- currence of the two different sexual products. The learned editor of the American transla- tion of Von Siebold's " Comparative Anatomy of the Invertebrate Animals," Dr. Waldo Burnett, has given, at p. 464. of that work, a short statement of his own observations on the origin and mode of formation of the re- peated broods or colonies of Aphides, made on a large species of that insect, viz., A. * Zeitsch. fur Wissen. Zool., vol. i. p. 190. [114] OVUM. Caryae, and of his views as to the nature of this process of non-sexual reproduction in general. The viviparous Aphides, according to Dr. Burnett, are neither male nor female, and do not possess, as has been supposed, any ovaries or oviducts. The new colony already begins to be visible within the body of its parent before the latter has itself been brought forth. The substance in which the new progeny takes its origin consists, at first, either of a single nucleated cell of ^V^" in diameter, or of a small mass of these cells at- tached in the same place as that occupied by the ovary in the oviparous females. These masses increase in quantity, are subdivided by a kind of notching into more numerous masses ; and each of these being inclosed in a capsule, the whole come to be arranged in a continuous row or series. There is not, however, any germinal vesicle nor segmenta- tion, as in the sexual ova ; and when develop- ment of the new insects is complete, it is by fulling into the abdominal cavity, and by es- caping through a genital aperture (porus genitalis) that the offspring is excluded. With regard to the origin of the cellular mass or germ from which the non-sexual progeny proceeds, Dr. Burnett states that a small mass, of a different appearance from the germinal part of the ovum, is seen to be in- cluded within the arches of the embryo ; and the next colony is produced from this mass. He regards this process as analogous rather to one of internal gemmation than of true generation, coinciding therefore more nearly with the views of Leuckart and Carpenter than of Steenstrup and Owen. Arachnida. — The ova of nearly all the higher Arachnida do not differ much in their internal structure from those of Insects ; but they do not present the same varieties of ex- ternal form. Their mode of first origin is also very different. All the higher Arachnida are, like Insects, of separate sexes. The Tar- digrada are hermaphrodite; and in these as well as some other simpler Arachnida, as Pycnogonida .and Acari, the ovum, though proportionally of large size, is of extremely simple structure, approaching very nearly to that of the lowest classes of Invertebrate animals. The ova of the higher Arachnida are gene- rally spheroidal ; the chorion or external membrane is generally smooth ; the vitelline membrane is slender, clear, and structure- less ; the yolk-substance is not unfrequently coloured, often purplish, consisting of a consi- derable quantity of large oily-looking globules, smaller granules of various sizes, and larger corpuscles which have been looked upon as cells, but which Leuckart states are only ag- gregated masses of granules held together by a viscid substance. The germinal vesicle is proportionally large, placed eccentrically, and possesses a macula, which in some genera is simple and flattened, as in the Scorpion, in others multiple and granular, as in Epeira. The formation of the ova may be observed in Arachnida with great ease, from the manner in which they are disposed in the ovary, pro- jecting like bunches of grapes from the central part of that organ, in almost every stage or degree of advancement. The process has been carefully observed by Wittich* and others. So soon almost as the ovum begins to be formed, it causes a bulging or projec- tion of the membrane from the surface of the ovary ; and when that has somewhat increased in size, the ova hang or project from the sur- face in small pediculated ovi-capsules. Ac- cording to Wittich, V. Cams f, and Leuckart, the part of the ovum which earliest makes its appearance within the small ovicapsules is the germinal vesicle. At first it appears quite sim- ple and without a macula, which last soon after- Fig. 80*. Ovarian ova of the Spider. ( From Wittich.') a. Small fragment of the ovary of Epeira diadema from which three ova project in the early stage of their development previous to the formation of the yolk : the germinal vesicles are enclosed in the membrane formed by the bulging out of the ovarian substance. b. Two ova similarly situated, but more advanced ; the primitive granular yolk substance intervening between the germinal vesicle and vitelline mem- brane. c. An ovum still more developed ; the germinal vesicle occupies the upper part ; in the finely gran- ular yolk substance below is seen the dark body regarded by some as a yolk nucleus, presenting an appearance of concentric lamellar structure ; towards c. in the figure, or close to the connecting pedicle, the large nucleated cells are seen, which usually occupy that situation, and appear to give rise to the cellular yolk substance. d. More advanced ovum greatly increased in bulk, the pedicle diminished, and the yolk com- pletely occupied by the larger cells or corpuscles ; the yolk nucleus has disappeared or is obscured. e. 8f f. Different forms of the yolk nucleus or dark body, which for a variable time is placed within the ovum during its formation. * Die Entstehung des Arachnideneies im Eier- stock, &c., Muller's Archiv. for 1849, p. 113. f Zeitsch. fur Wissen. Zool., vol. ii., 1850, p. 97. OVUM. [115] wards appears as a small dot or nucleolus. The yolk begins, in the same manner as we have had occasion to state in many other animals, first by the clear deposit of a basement sub- stance round the germinal vesicle, and the subsequent formation of opaque granules in it ; the vitelline membrane is of later for- mation. As the egg increases in size, the larger corpuscles and the fat globules gra- dually appear. The ovarian ova of several spiders contain besides the usual parts another body of a peculiar kind, the nature of which seems still involved in some doubt. This body is eccentrically placed near the yolk mass of the primitive ovum, and is of considerable size, viz. about ?h/', of a yellowish colour, and, during the earlier part of its existence at least, consisting of concentric layers of a hard granular matter. V. Cams* has compared this body to the yolk-nucleus of the Frog's ovum ; and both he and Von Siebold seem disposed to consider it as in some way or other the source of the granular substance of the yolk ; but according to Wittich this view is not well founded, as he has observed the body remain- ing in the ovum till it reaches maturity, though it loses its concentric laminated structure, and becomes clearer and vesicular. Von Siebold, on the contrary, states that it gradually disap- pears. The large clear or oily globules appear, according to Carus, to be produced from near the pedicle of the ovum, at a place where there is fixed a group of cells apparently destined for their formation. No observations have as yet been made, so far as I am aware, on the existence of a mi- cropyle in the ova of Arachnida. Almost all the Arachnida are oviparous. The Scorpions are an exception, however, bearing their young alive ; and it is deserving of notice that in this family the embryo is deve- loped in the ovum while it still remains in the ovary. In the greater number of this class em- bryonic development commences in a blasto- derm, which covers only a part of the surface of the yolk, situated in what may be called its lower part or pole •}• ; and the segmentation of the yolk is therefore limited or partial, as in Insects. In the higher Arachnida the steps of this process do not appear to have been yet satisfactorily observed. I may refer, however, to the researches of Kaufuiann of Lucerne on the development of the Tardigrada, as afford- ing clear and beautiful illustrations of the process of segmentation, which is shown to be complete in the lower Arachnida.J Crustacea. — All the animals of this class are of distinct sex ; but in the allied Cirrhipedia hermaphroditism most frequently prevails. In some of the Cirrhipedes, however, it has been shown by Mr. Darwin $ that the sexes are * Loc cit, p. 99. t See the Researches of Herhold De General. Aranearum in Ovo, 1824 ; and Rathke, zur Mor- phol. Reisebemerkung. 1837; and in Burdach's Physiologie. I Zeitsch. fur Wissen. Zool., vol. iii., p. 220. See Plate vi.f figs. 3. to 11. § Monograph of the Sub-class Cirrhipedia, &c., printed by the Ray Society, 1854, p. 27, &c. also distinct, as in some of the species of the genera Ibla, Scalpellum, Alcippe, and Crypto- phialus. In these instances the males are very minute, and are attached, almost like pa- rasites, to certain parts of the more developed females, the place of their attachment varying in different species. It is interesting to ob- serve that these males, as in the case of several of the Epizoa, are often of the most rudimen- tary organisation.* The ova of the greater number of Crustacea, especially the more highly organised genera, belong, like those of most of the Articutata, to the group in which a considerable amount of nutritive yolk is present along with the for- mative part, and in which the process of seg- mentation in the latter is partial. The forma- tive disc is situated on the lower surface of the ovum ; and from that part the development of the embryo emanates. Even among the higher decapodous Crustacea, however, the ova are of very various sizes -j-; and in the lowest genera, as among the Entomostraca, the ova are proportionally the largest, although they are of the simplest structure, and present the smallest amount of nutritive yolk ; so that, in this as in other classes of animals, magnitude alone is no true criterion of the internal structure of the ovum. The ova of this class have been described principally by Rathke J, by Erdl$, R. Wag- ner |j , Leuckartl, Leydig**, and others ; but the knowledge both of their structure and their mode of formation is yet far from being sufficiently minute or complete. They pre- sent, indeed, many varieties, which renders it difficult to give any general description of them. The following may however be stated. The ova of Crustacea are often variously and brilliantly coloured. The yolk-substance con- sists of a large quantity of clear globules of considerable size, having the aspect of oil globules, in which the colouring matter chiefly resides. In some ova these globules attain the size of ^^ of an inch. There is also a more fluid granular matter in the yolk, and in the more mature ova there is a layer or disc of granular corpuscles on one side which after- wards is the seat of segmentation and embry- onic formation. The germinal vesicle is of considerable size, in some instances possess- * It is also a remarkable fact, pointed out by Mr. Darwin in his interesting Researches, that even among the hermaphrodite species there are some- times distinct male individuals attached parasiti- cally to the hermaphrodite animals ; these have been called complementary males. t Thus, for example, the ova of the river craw- fish (Astacus fluviatilis) are twice as large as those of the common lobster. J Entwickel. des Flusskrebses, 1829; in Bur- dach's Physiologie, vol. ii. 1837 ; in his Abhandl. zur Bildung und Entwickel. Gesch. &c., 1833 ; in Dissert, de Animal. Crustac. Generat 1844 ; and various other treatises. § Entwickel. des Hummereies, 1843. || Prodrom. Hist. Generat., 1836. *B" Article Zeugung. ** On Argulus foUaceus in Zeitsch. fur Wissen. Zool., vol. ii. [116] OVUM. ing a single nucleus, in others multiple ma- culae. The formation of the ova may be observed with ease in any of the smaller isopodous Crustacea. According to Leuckartin Oniscus or Armadillo, it is essentially the same as in the Arachnida. The ova consist at first of germinal vesicles, originating below the epi- thelial lining membrane of the ovarian sac. The yolk-substance first appears as a clear deposit round each germinal vesicle ; minute opaque granules are then formed in this sub- stance, and subsequently the larger albuminous and oil globules gradually make their appear- ance. The vitelline membrane, which is very delicate and structureless, is added at a com- paratively late period, in the Oniscus for ex- ample, when the ova are about y^/' in diameter. In many of the Crustacea the ova also acquire a chorion or shell membrane of con- siderable strength. On arriving at the lower part of the female passages, the ova of many genera also receive an addition of a peculiar so-called albuminous secretion, which becomes coagulated in water, and thus, when the eggs are laid, serves to glue them together in heaps or to cause them to adhere to the hinder feet, caudal plates, &c., of the parent, where, as is well known, they remain during the whole Fig. 81*. Ephippial ovum of the Daphnidce. ( From Haird.} The figure represents a profile view of the female of Moina rectirostris (one of the Daphnidas) show- ing at a. the ephippial ovum in its usual place on the back of the animal. progress of embryonic development. In the Monoculi and some other Entomostraca, there are marsupia or pouches appended to the genital orifices of the parent, in which the ova are retained during the formation of the young. In all the bisexual Crustacea the ova are fecundated while still within the body of the female parent ; but the phenomena and period of this process have not yet been acurately determined, partly perhaps in consequence of the peculiar form and motionless condition of the spermatic corpuscles belonging to the greater number of this class. No micropyle has yet been observed in the crustacean ovum. From the observations of several naturalists it is now well ascertained that in the ento- mostracous Crustacea, there commonly occurs a production of young individuals without impregnation, somewhat in the same manner as previously described in the Aphides. " In the Daphnia," says Dr. Baird*, "it is now clearly ascertained that a single copulation is sufficient, not only to fecundate the mother for life, but all her female descendants for several successive generations ;" and it was considered probable by Jurine, that in some species this might extend to the fifteenth gene- ration. In the Daphnia and other similar Ento- mostraca, the ova are transferred from the ovary into a cavity situated below the shell on the back of the animal, which has been called uterus, perhaps erroneously, and there undergo development. But at certain seasons many of these Entomostraca produce ova of a different kind from those now referred to. To these the name of winter or hybernating ova has been given, as they appear to be adapted, from the strength and impermeability of their external coverings, to resist the in- jurious effects of cold and other atmospheric influences during the winter season. These ova are generally in smaller number than those of the ordinary kind, frequently two, some- times only one; and they are contained and undergo development in a peculiar case, which is formed on the back of the animal below the shell, nearly in the same situation as the matrix for the ordinary ova. This case, which afterwards separates "from or is abandoned by the animal, forms a sort of hump or saddle on its back, and has hence been named the ephippium, and the eggs have been called ephippial ova. These ephippial ova, according to Baird, are already fecundated by the original impregnation of the female parent, and do not require, for themselves nor for their progeny for several generations, any renewed or special impregnation. It appears from the observations of Jurine, Strauss, and Baird, that at the time when the ephippial ova are about to be formed, a sudden change takes place in the appearance of the ova, by the deposit of a quantity of dark granu- lar substance. This appears to be transferred * Nat. Hist, of the British Entomostraca, Ray Soc. Public., p. 79. OVUM. [117] into the cavity behind, in which an increased growth of substance round the ova and within the shell gives rise to the production of a two- valved case for containing the ova. Accord- ing to S. Fisher of St. Petersburg *, the for- mation of the ephippial ova may be noticed during the whole season, from the middle of July onwards ; and it may therefore be inferred that these ova have for their object the pre- servation of the species in the heat of summer when the ponds are liable to be dried up, as well as by resisting the cold of winter. Von Sieboldf states that these hibernating ova contain no germinal vesicle ; and Dr. Burnett, in his translation of Von Siebold's work, has adduced various arguments in fa- vour of the view that this is an instance of "internal gemmiparity" (as he regards the corresponding phenomenon in Aphides) rather than the production of true ova. "Sufficient data are still wanting, however, to form a de- cided opinion on this subject, as we cannot at present distinguish between the ova of the Entomostraca which are the result of fecun- dation, and those which are formed and de- veloped independently of the concurrence of the male.J Anmdata. — In the class of Annulate Worms, including the Leeches, Earthworms, Nereids, and Amphitrites$ , although considerable va- rieties present themselves in the modes of reproduction, there is yet a greater degree of uniformity in the structure of the ova than in some of the classes previously referred to. In the greater number the ova are nearly spherical in form, of rather small size ; the yolk-substance is generally finely granular, and segmentation is complete; the germinal vesicle is clear, with a distinct single macula, or one which is elongated or only slightly divided into subordinate particles. In most ova of Annulata there is, in addition to the inner transparent vitelline membrane, a cho- rion or external membrane of considerable strength, and not unfrequently a superadded layer of albuminous substance, which unites the ova in groups or cocoons, or serves to attach them to other bodies. \ In Clepsine, among the Hirudinea, the yolk- substance differs from the common form above described, being composed rather of larger- sized globules ; and in another genus belong- ing to the same order, Piscicola, according to Leydig \, there are peculiarities of structure * Mem. of the St. Petersburg Acad., 1848, torn, vi., p. 162. f Compar. Anat. j See Burnett, loc. cit, p. 353; Zencker, tiber die Daphuoidae in Muller's Archiv., 1851, p. 112; and Leydig, tiber Artemia salina und Branchipus stagnafis, in Zeitsch. fur Wissen. ZooL, voL iii. 1851, p. 297. § Suctoria, terricola, errantia, and tubicola. || For a clear and comprehensive account of the reproduction of the Annelida in general, and with special reference to the genus Hermella, one of the suctorial Annulata, the excellent memoir of Quatre- fages, in the Annal. des Scien. Nat., 1848, vol. x. p. 153, in which, in addition to his own researches, are duly recorded those of previous observers. \ Zeitsch. fur Wissen. Zool., vol. i. p. 123. which have not as yet been referred to any general law. In the ova of these animals the covering is double, consisting of a delicate in- ternal vitelline membrane, and an external envelope or chorion, to which a layer of dis- tinct flattened and nucleated cells is adherent; and within the vitelline membrane there is a collection of nucleated cells which displace and partially surround the usual finely granu- lar or formative yolk-substance. Leuckart* informs us that the same peculiarity exists in Pontobdella; but the nature and destination of this inner cellular part of the ovum does not appear as yet to be understood in either of the animals mentioned. In the Piscicola, Leydig observed the ovum, while within the ovarian cavity, to be com- pletely surrounded for a time and enclosed by a consistent mass or covering of spermato- zoa; and it has been observed that in this animal the germinal vesicle has not in general disappeared till some time after the ovum has thus encountered and been enveloped by the mass of spermatic substance. In the Lumbricus, Meissner-f- has made the novel and interesting observation, that pre- vious to the encounter of the spermatozoa with the ovum, the latter loses the vitelline membrane which before covered it, and that the spermatozoa then penetrate, in great numbers, the whole surface of the exposed yolk. Fig. 82*. Ova of tfie Lumbricus during fecundation. (From The figures represent three views of the ova of Lumbricus agricola, a. §• b. on their flat sides, c. seen edgeways. Over the surface spermatozoa are seen penetrating the vitelline substance, giving to it on a large scale the appearance of a ciliated surface. The ovum which has now reached the receptaculum seminis is without vitelline membrane, the yolk being thus directly exposed to the action of the spermatic masses ; but the vitelline membrane ex- isted at an earlier period and disappeared by solu- tion in the course of the descent of the ovum. The development of the ova in Hermella has been minutely described by Quatrefages ; and this may be taken as an example of the general nature of this process among the * Article Zeugung, p. 809. t On the penetration of spermatozoa, &c., in Zeitsch. fur Wissen. Zool. voL vi. [13] [118] OVUM. Annelida. According to this description, the first germs of the ova consist of minute ger- minal vesicles formed in the ovarian sub- stance; they soon acquire the single macula or nucleus. After undergoing some enlarge- ment, these germs fall into the abdominal cavity, and there acquire, by deposit round them, the clear primitive vitelline substance. In this substance opaque granules, which are at. first colourless, are subsequently deposited; and as these extend outwards from the ger- minal vesicle, and accumulate in quantity so as to increase the bulk of the whole ovum, a delicate vitelline membrane is added exter- nally. The germinal vesicle attains a diameter of about -g-^o"* a"d its macula of ^5^5"; and when the several parts of the ovum which have been mentioned have appeared, and the yolk is now coloured, the whole ovum has a diameter of about -s^". The superficial part of the yolk consists of minute coloured granules. Within this there are larger oil-like globules free of colour, and in the innermost part a somewhat viscous transparent fluid.* According to Ley dig, the germinal vesicle in Piscicola becomes enveloped by a second vesicle or cell-wall before the formation of the yolk-substance ; but it is suggested by Leuckart that he may have been misled in this by the appearance often presented by the clear and somewhat highly refracting substance which in many animals precedes the formation of the opaque yolk. If this is not so, the fact observed by Leydig would constitute a marked departure from the usual homological relations of the ovum.f Rotifera. — Although most zoologists are now disposed, on the ground of the analogies in the most important parts of their general structure, to place the Rotifera among or close to the Articulate Worms, yet in some re- spects their mode of reproduction presents a marked correspondence with that of the lower Crustacea. Thus they have, in com- mon with some of the lower Crustacea, the occasional separate condition of the sexes, the preponderance of females, the imperfect development of the males, the proportionally large size of the ova, and the production of winter ova as well as the ordinary kind ; on the other hand, the simpler structure of the ovum and its complete segmenta- tion are more similar to what is observed among the Vermes. f * Quatrefages, it is to be observed, designates the enveloping membrane ovarian and not vitel- line membrane, which last he holds is wanting in these ova. f Farther interesting views of the ova of this class will be found in Milne Edward's memoir in the Annal. des Scien. Nat. for 1845, vol. xxiii. p. 145 ; and in his article ANNELIDA in this Cyclopaedia, to which I must refer the reader ; in Grube's Unter- such, uber die Entwickel. der Clepsine, Konigsberg, 1844. H. Koch, Ein Worte zur Entwick. von Eunice, with an Appendix by Kolliker, on Exogone and Cystonereis. \ See Leydig, On the Structure and Systematic Position of the Rotifera, &c., in Zeitsch. fUr Wissen, The relation of the sexes in Rotifera has only recently been in any degree under- stood, and that only in a few genera ; and there are still many points requiring elucida- tion. The greater number of the animals, in fact, which till lately have been known or de- scribed in this class have been females ; and as yet the males or male organs have been as- certained only in a few genera. Some are certainly of separate sexes, as Notommata, and the allied Rotifer of which the male was first discovered by Brightwell*, and of which the development was described by Dalrymple f, Others seem to be hermaphro- dite, as in Megalotrocha, described by Kol- liker^; ; in Euchlanis, by Schmidt § ; and in Lacinularia socialis, by Leydig. || But ac- cording to Huxley % there may still be some doubts as to the bodies described as spermatozoa, and as to the arrangement of the male organs in the Lacinularia. Fig. 83*. Ovarian ova of Rotifera. (From Huxley.") The figures represent the formation and develop- ment of the true or ovarian ova of Lacinularia socialis (one of the Rotifera). A. and B. are small fragments of the ovarian substance showing the primitive ova with their germinal vesicles and maculae ; in B. one of the ova more advanced than the rest. c. represents the mature ovum. D. the same undergoing the first stage of segmentation. The ova of Rotifera have been observed by Ehrenberg and many other microscopists. They are of comparatively large size, but yet belong to the group of ova possessing the simpler kind of structure, the yolk substance being quite finely granular, and undergoing a complete segmentation. The germinal vesicle is large, and possesses a distinct single ma- cula ; and the whole ovum is inclosed in a clear vitelline membrane. No micropyle has yet been discovered, nor have the time and Zool., vol. vi. ; and C. Vogt on the same subject in vol. vii. of the same work. * Ann. of Nat. Hist, for Sept. 1848, p. 153. t Philos. Transact., 1849, p. 331. t Froriep's Neue Notizen, 1843, p. 17. § Vergleich. Anat. p. 268. || Zeitsch. fur Wissen. Zool., vol. iii. Tf Microscop. Soc. Trans, p. 1. in vol. i. of Microsc. Journal, 1853. OVUM. [119] phenomena of fecundation been minutely ob- served. The formation of these ova may be traced with facility in the substance of the ovary, in consequence of the transparency of the ani- mals. The nucleated germinal vesicle seems first to make its appearance ; the granular }olk substance follows; and the vitelline membrane is last formed.* The Rotifera present another example of the formation in the autumn season or before winter, of that variety of the reproductive body which has been called winter egg, and which has already been noticed under the Entomostraca. These bodies were observed by Ehrenberg in Hydatina and Brachionus, by Dalrymple in Notommata, and by Huxley and Leydig in Lacinularia. They are twice the size of the ordinary ova, are formed in very small numbers, probably only two, as is most common in Daphnia, and contain no apparent germinal vesicle. Mr. Huxleyf- ap- pears to have pointed out very clearly the dis- tinction between true or ordinary ova and these reproductive bodies. He says, at p. 16 of his paper, " The true ova are single cells which have undergone a special development, the ephippial ova are aggregations of cells, in fact larger or smaller portions, sometimes the whole of the ovary, which become enveloped in a shell and simulate true ova." Mr. Huxley Fig. 84*. Formation of Ephippial ovum in Lacinularia Socialis. (From Huxley.) A. represents a portion of the ovary massed together and undergoing a change of structure pre- paratory to its conversion into the ephippial ovum. B. the ovum now complete, the external invest- ment distinct. c. the same having now its contents divided into two portions. The ephippial ova differ from the ordinary ones in their mode of formation, and in having'three investments. has traced minutely the process of conversion of the substance of the ovary into such an ephippial ovum, or rather the protecting covering of the two ova which are contained in the ephippium ; and his observations seem to show a manifest difference between these and the ordinary ova. The same follows also from Mr. Dalrymple's researches on No- tommata. The correspondence of the num- * Leuckart, loc. cit. t Loc. cit. ber and general structure of these ova in Daphnia and the Rotifera is also deserving of notice. These winter ova, besides being much larger than the ordinary ones, differ from them also in structure, having three investing membranes; and they appear designed, like those of the same kind in other animals, to resist the cold of winter and other hurtful influences. It would appear that these ephipphial ova, like those of Daphnia, do not require fecunda- tion. Leydig, though distinguishing the two kinds of ova, regards the hybernating ova as only modifications of the ordinary ones ; while Huxley considers them rather as pecu- liar buds like those of Aphis or Gyrodactylus.* Turbellaria. — Under this class three orders of the animals allied to the Planaria may be brought, according to the researches of Qua- trefages and others, viz., the two kinds of Planaria with simple and ramified alimen- tary canal, or Rhabdoccela and Dendrocoela, and the Nemertides or Mioccela. The first two orders are hermaphrodite ; in the third the sexes are distinct. The ovology of this class is known principally from the interesting and beautiful researches of Quatrefages f; but the history of the structure and formation of the ova is still far from being complete. The ova of the Planariae are of various magnitudes, and present some differences in their structure. For the most part they con- tain only the finely granular yolk, but with oc- casionally some oil globules interspersed. It is only in the earliest stages that the germinal vesicle is perceived with ease, in consequence, probably, of the opacity of the yolk-substance, and the dark colour of the external envelopes. In most of the genera the germinal vesicles and the yolks are formed in separate organs, as in the trematode animals, to which the Planarias are nearly allied, but in some, as Macrpstomum, these two organs come to be combined in one. At first the yolk-mass, in descending and meeting with the germinal vesicles, unites a number of them into a con- nected chain ; but somewhat later the ova are separated into distinct spheres, and a vitelline membrane is formed to enclose each of them. Just as occurs in the body of the adult Planariae, there is also in the ova a remarkable tendency to subdivision by fission. Thus, in the commencement of the development of the ovum, it is liable to become divided into distinct masses, so as to give rise to the de- velopment of a number of embryoes from one ovum. Such, at least, is the view entertained by some ; but there may be doubts as to whether the ovum so divided is really simple, * See on this subject also, Burnett's translation of Yon Siebold's Comparative Anatomy, p. 150. f Me'm. sur quelques Planarie'es Marines, in Annal. des Scien. Nat. 1845, torn. iv. p. 169 ; and Me'm. sur la Famille des Nemertiens (Nemertea), id. lib. 1846, torn, vi., p. 269. The Rhabdocoala are known chiefly by the researches of Schmidt, Die Rhabdocoelen Strudelwiirmer des siissen Was- sers, Jena, 1848; and of Schultz, Beitrage zur Geschichte der Turbellarien, 1851. M] [120] OVUM. or is rather a collection or aggregation of a number of germs surrounded by a common yolk ; in fact, as has been suggested, an ova- rian sac containing a number of ova.* The manner in which the spermatozoa reach the ova for fecundation does not appear to have been ascertained with accuracy. Entozoa. — The ovology of the Helmintha or Entozoa has received considerable atten- tion from physiologists, both on account of the interesting nature of the phenomena pre- sented by its study, and because of the anxiety to discover the mode of production of these parasites within the bodies of other animals. From the researches on this subject which have been prosecuted with great assiduity by a number of observers in recent times, not only have many doubtful points been solved as to the origin of the Entozoa, and the views of naturalists greatly modified in regard to the history of these animals, but considerable assistance has also been received in the elu- cidation of general questions in ovology. I will give a short sketch of what has been most recently ascertained on this subject under the three divisions of the Nematoidea, including all the Round Worms, the Trematoda, and the Cestoidea including the Cystica. All the animals belonging to the first division are bisexual, and the production of the embryo is direct from the ovum, without metagenesis or metamorphosis ; in the two other divisions hermaphroditism prevails, and development is indirect, or accompanied by metagenesis and metamorphosis in the greater number. Nematoidea. — The genital organs in the first of these orders present the same favourable circumstances as those of Insects for the ob- servation of the structure and formation of the reproductive elements in their successive stages, as in the different parts of these tubu- lar organs there are to be found at once the spermatic cells and spermatozoa, and the ger- minal cells and ova in every conceivable de- gree of advancement from their earliest ap- parition to the state of maturity. In the Ascarides and most of the round worms, the upper closed extremities of the two genital tubes of the female correspond with an ovary, or rather as a portion of it which may be regarded as a germ -form- ing organ ; for in this upper part of the tube are produced only the nuclei or nucleated cells, from which the germinal vesicles derive their origin. A second portion of the tube, in which the granular yolk substance is added, is to be looked upon also as a con- stituent part of the ovary, and may be called the yolk-forming or vitelligenous organ. Next follows a constricted part of the tube, which may be termed oviduct, in which the ova meet with the spermatic corpuscles and undergo fecundation. From this the ova pass into the fourth compartment, a dilated portion which has been called a uterus, and below this * Burnett's transl. of Siebold's Compar. Anat. p. HO. the two genital tubes finally unite into a com- mon vagina. In the Ascarides, the process of formation Fig. 85*. Development and fecundation of the ova of Ascaris mystax. A. Earliest stage of the ova as they are found in the ccecal or uppermost part of the ovarian tube ; some from the highest part are mere molecules, others a little farther down are minute nucleated cells (germinal vesicles or germs of the ova), and round these the primary yolk granules are be- ginning to collect. B. Ova from the second part of the ovarian tube in which they are closely pressed together and arranged in a radiated manner round the axis or centre of the tube. To the right, four of these ova are represented adhering together ; to the left, two ova are shown with their flat surfaces, and one with its thin edge towards the observer. The ex- ternal dotted line represents the surface of the basement substance of the yolk in which the opaque vitelline granules are deposited ; there is as yet no vitelline membrane ; the germinal vesicle and macula are very distinct. c. An ovum from the oviduct ; a faint marginal line indicates the place where the vitelline mem- brane is afterwards formed. The germinal vesicle still visible, though obscured by the yolk granules ; the ovum has now assumed an ovoid shape. D. Softened state of the ovum at a slightly later stage, when it has met with the spermatic cor- OVUM. [121] puscles ; which are held by Nelson thus to pene- trate or gain access to the vitelline substance. K. Ovum more advanced ; the vitelline and albuminous membranes formed; clear highly re- fracting spaces resembling altered spermatic cor- puscles are seen in the yolk substance. F. Ovum after fecundation; uniform structure of the yolk substance previous to the appearance of the embryonic cell and commencement of segmenta- tion. The chorion has now become tuberculated. of the ova appears to consist, first, in the production of minute cell-germs in the upper- most part of the ovarian tube immediately adjoining its coecal termination. It does not appear to be fully ascertained whether these germs are originally, as some have supposed, the maculae or nuclei, or rather, as others hold, the germinal cells or vesicles themselves : the latter opinion appears to be the most probable. Second, the granules of the yolk-substance very soon collect round the exterior of the ger- minal vesicles. These granules appear at first to be suspended in fluid ; but a little later, as they come to collect round the germinal vesicles, they are united together in a mass by a firmer but clear basement substance, and when the minute ova have somewhat in- creased in size, the outline of this clearer basement substance of the yolk is distinguish- able. There is not, however, at first any ex- ternal or vitelline membrane ; of this Dr. Nelson and I have convinced ourselves by re- peated observations in Ascaris mystax.* The ova, as they continue to descend in the vitelligenous part of the tube in immense numbers closely pressed together, assume the form of subtriangular flattened bodies, and come to be arranged in series of three, four, or more, in a short spiral round the centre of that part of the ovarian tube which constitutes the yolk organ, as round a central axis, but without being united together by any com- mon stalk or other structure. A prodigious number of ova are thus packed together in a very small space. In passing through the next part of tube, which forms an oviduct, the ova are detached from the spiral and closely-set position, and being surrounded by fluid, which must here be secreted within the tube, descend one by one through its narrower part. At this place they encounter the spermatic corpuscles when they are present, and undergo the change of fecundation ; but whether fecundated or not, the ova now lose their germinal vesicles, alter their form from that of flattened triangles to oval, become for a time much more yielding and soft, and somewhat later begin to acquire an external covering which they have not previously possessed. The peculiar motionless and tailless sper- matic corpuscles appear, therefore, to come into contact with the ova when the yolk is exposed directly to their action. According to the interesting observations of Dr. Henry * See Nelson's paper on the Reproduction of the Ascaris Mystax in the Trans. Roy Soc. of Lond. 1852, p. 563., pi. 28, figs. 48. and 50. Development of Spermatic Corpuscles in Ascaris mystax. This figure is introduced to show the several stages of development of the peculiar acaudal and motionless spermatic corpuscles of the Ascaris mystax. A. shows various stages of the primary sperm - cells or rather sperm-germs; in the more advanced of which towards the right, internal cells are seen forming by endogenous production within the primary germ-cells. B. & c. show the second stage, in which the sepa- rated germ-cells have each become covered by a finely granular mass collected round them ; in B. this process is beginning ; in c. it is completed, and the sperm cells thus formed have assumed an ovoid shape. D. Two views of sperm-cells in the third stage, in which a quadrifid division of the whole cell has taken place preparatory to the escape or separation of the spermatozoon-cells, usually four in number, proceeding from each sperm-cell. E. Various views of these spermatozoon cells in which the radiated linear marking (seen in D.) has disappeared, and is again resolved into granules ; the nucleus is seen from above in the left-hand figure ; in the three others being viewed in profile the appearance of the bell-shaped spermatic cor- puscle with the nucleolus is perceptible. F. Exhibits from right to left the various pro- gressive stages of the bell-shaped corpuscle into the test tube form ; the remains of the nucleolus and granular substance are seen towards the mouth of the flask-shaped bodies. o. Illustrates the effect of water in developing " Sarcode " on the exterior of these corpuscles in two different stages of their advancement. [122] OVUM. Nelson,* a peculiar softening of the ova, which may be caused by the rapid imbibition of fluid at the time the changes above mentioned are taking place, renders them peculiarly liable to be impressed by the spermatic corpuscles at Fig. 87*. Development of ova in Mernris albt'cans, belonging to the Gordiacei. (From Meissner.} a. Germ-cells from the upper or coecal end of the ovarian tube, their nuclei undergoing subdivision. b. Various stages of farther multiplication of the internal cells, which in the more advanced are seen to approach the surface of the original cell, and to cause the bulging of its membrane by the enlarge- ment of the internal cells, which last constitute the primitive ova. * Loc. cit., p. 576. c. §• d. Groups of primitive ova thus formed ; some of them much more developed than others, present- ing internally the nucleated germinal vesicles and yolk'granules and attached in pediculated capsules, which are formed by the extension of the membrane of the primary germ cells. e. A group of these ova more advanced; the opaque granular yolk increased in quantity so as to obscure in part the germinal vesicles ; the pedicles much narrowed and somewhat elongated ; the ex- ternal ova are nearly mature ; those in the centre remain abortive. f. Two similar ova now ripe, a part of one of them is artificially burst, showing the escape of the yolk granules and germinal vesicle with a double macula. The remains of the pedicles when detached from the central mass constitute, according to Meissner, the micropyle aperture. this period; and Nelson is of opinion that these corpuscles even penetrate completely into the yolk-substance, and ultimately com- bine with it. Little doubt can be entertained that a combination of the spermatic and vitel- line elements in some manner takes place at this time, whether by the direct interpene- tration after the mode described by Nelson, some may be inclined to doubt; but at all events the spermatozoa act immediately on the vitelline substance at this stage of the progress of the ovum. * As the ovum descends in the next part of the tube or uterus, the external membrane becomes more dense, additional layers are deposited upon it, and at last it acquires more * Professor Bischoff has, in his recently published tract " Wiederlegung des von Dr. Keber bei den Naiaden und Dr. Nelson bei den Ascariden behaupte- ten Eindringens der Spermatozoiden in das Ei," &c., Giessen, 4to., 1854, called in question the accuracy of Nelson's observations, and asserted that Nelson's spermatozoa are only epithelial particles belonging to the female passages. In a subsequently pub- lished paper, entitled, " Bestatigung des von Dr. Newport bei den Batrachiern und Dr. Barry bei den Kaninchen behaupteten Eindringens der Sper- matozoiden in das Ei, Giessen, 25th March, 1854," although Bischoff has seen reason to alter his pre- vious views as to the phenomena of fecundation in the Ascaris mystax, he still in that paper, and in a special memoir on the subject, published in the Zeitsch. fur Wissensch. Zool., 1854, vol. vi. p. 377. adheres to the view that the bodies which I, along with Nelson and Meissner, regard as spermatozoa are no more than epithelial cells. I have elsewhere shown that this view is altogether untenable, and that no doubt can now prevail as to the corpuscles in question being the product of development from the spermatic cells of the male Ascaris, and as to the possibility of their direct action on the ova within the female previous to the formation of the vitelline membrane. Meissner has also given the most satisfactory evidence on the same point in his memoir on the penetration of the sperma- tozoa into the ova of animals, contained in the same volume of the last quoted work, though this author takes a different view from Nelson and my- self as to the manner in which the spermatozoa are admitted into the ovum in Ascaris mystax, believing in the existence of a vitelline membrane and micro- pyle, in the same manner as in Mermis and other Gordiacei, which he has so well described. With regard to this view as applied to the Ascaris mystax, Bischoff's observations, Nelson's, and my own, give me the greatest confidence in asserting that there is at first no vitelline membrane in this animal at the time when the ova first meet with the spermatic corpuscles. OVUM. [123] or less of a minutely tuberculated structure on its external surface. The ovum becomes of a regular short oval or nearly spherical form. If fecundation shall have" occurred, the embryonic vesicle or cell makes its ap- pearance, and the phenomena of segmentation follow in rapid succession. Fig. 88*. Formation and fecundation of the ova of Nematoid Worms. (According to Meissner.) a. A portion of the ovarian axis and early ova attached to it from the ovarian tube of Strongylus armatus. The axis column occupies the centre of the tube, and the ova are suspended to it by pedicles, supposed by Meissner to form micropyle apertures when they are detached. b. View given by Meissner of a set of the nearly ripe ova of Ascaris mystax, which he conceives are thus connected by pedicles to a central axis. c. Two mature" ova of the same surrounded and in part penetrated by spermatic corpuscles. At the narrow angles of these ova a spermatozoon is seen passing into the interior by what Meissner has regarded as a micropyle formed by the detached pedicle. In the ovum to the right a spermatic cor- puscle is seen in the vitelline substance. The existence of such a micropyle aperture and pedicu- lated attachment of the ova in the Ascarides 1 re- gard as doubtful. In others of the Nematoid Worms and more especially in Strongylus and the Gordiacei, it would appear from the researches of Meiss- ner, that the first germs of ova which take origin in the uppermost part of the ovarian tube multiply by an endogenous production, and that in this manner groups or bunches of the primitive ova are produced which are con- nected together by pedicles arising from the Fig. 89*. Formation of ova and fecundation in Gordius Sub- bifurcus. (From Meissner.) a. A small portion of the ovarian tube with groups of the ova partly within and partly escaping from it. b. Three of the mature ova from the lower part of the oviduct surrounded by the spermatozoa. The ova are now isolated, and the pedicle of each is open, and is regarded by Meissner as a micropyle, by which spermatozoa, as represented in two of them, enter the ova. The germinal vesicle is still to be seen. elongated membrane of the original germ-cell which remains as a covering of the whole. A certain number of these ova make progress in development while others probably become abortive. As the ova enlarge they are more spread out in the tube and take something of the spiral disposition which exists in the Asca- rides, but with this difference, as already noted, that the various ova remain connected to- gether by the attachment of their pedicles to a central axis or stem running down the middle of the ovarian tube. On the subse- quent detachment of the ova by the break- ing of these pedicles, according to Meissner, a micropyle aperture is formed in each ovum for the admission of the spermatozoa. The accompanying drawings from Meissner's Memoir will give a sufficiently clear idea of his views on this subject. The ova of the nematoid worms constitute a marked example of the simpler kind of ovum in which the formative yolk is present, and [124] OVUM. in most but not in all of which segmentation is complete. This process was first made known through the interesting researches of Kdlliker*, in Muller's Archiv., 1843, p. 68, and Bagge, in his Inaugural Dissertation.-j- The memoir of Reichert in Muller's Archiv., 1847, contains very correct views as to the formation of the spermatic cells. The accompanying figure from Meissnerjl, gives a representation of a remarkable form of the external capsule of the ova occurring in some of the Gordiacei (Mermis nigrescensj. Fig. 90*. Mature ova of Mermis nigrescens. {From Meissner.) This figure is introduced to show the very pe- culiar capsule in which the ovum is enclosed. a. Ovum taken from the uterus with embryo enclosed ; the chorion and shell capsule with cha- lazae or brush-like processes attached to the latter. b, c. The shell capsule c burst across the equa- torial groove, allows the ovum b to escape with the chorion and embryo contained within it. The ova of Trematoda are generally of a long-oval form, and of middle size. They are enveloped by a shell membrane of consider- able firmness, and which is not unfrequently of a dark brown colour. The yolk-sub- stance contains fat corpuscles simple and compound ; and there is a germinal vesicle present, which, however, from the deep colouration and other circumstances, is often very difficult of detection. In these animals an interesting peculiarity in the arrangement of the reproductive organs exists, in the separation of the germ-forming and yolk-forming portions from each other ; in the first of these organs germinal vesicles or clear nucleated cells alone being produced, in the other the opaque granular fatty matter which furnishes the vitellus. This arrange- ment was first described by Von Siebold in 1836.$ The germ organ is generally in the form of a rounded sac, which is filled with the nucleated germ-cells or vesicles in various * See his admirable memoir on the first changes in the fecundated ovum, principally referring to the Entozoa. f Dissert, inaug. de Evolutione Strongyli auri- cularis et Ascaridis acuminatae, Erlangae, 1841. t ZeiLsch. fur Wissen. Zool. vii. pi. ii. § Wiegmann's Archiv., 1836, p. 217, Tafl. vi., and Muller's Archiv. 1836, p. 232, Tafl. x., fig. 1. stages of development. The vitelline organ is double, each one consisting of ccecal tubes, in which the opaque granular yolk-substance is secreted.* The ducts of these two organs meet in a common cavity or uterus, and the germs descending into this cavity are there enveloped by a portion of the vitelline mass, and shortly afterwards an enclosing vitelline membrane is formed. These animals being hermaphrodite, the vas deferens of the male organ or testicle leads into the uterine cavity ; and it would appear, therefore, that in many cases, if not in all, impregnation takes place by the access of the spermatic corpuscles to the elements of the yolk and germinal vesicle, just at the time when they are brought toge- ther to form the ovum. This separation of the germ-forming and yolk-forming parts of the ovarian organ, which is so apparent in the Trematoda, is not in truth so great a departure from the more familiar structure of other animals as might at first be thought ; for, as Leuckart has well observed, there are other examples of the same disposition, or an approach to it. Thus in Insects and in Nematoid Worms, as we have seen, it is from distinct parts of the genital tube that the germs and yolk are produced ; and more or less of the same arrangement exists in all instances in which the form of the ovary is tubular. The Cestoidea present a great similarity to the Trematoda in the arrangement of the organs by which the ovum is formed. Indeed, notwithstanding the difference of their antece- dent stages of development, the structure of the mature sexual joint or proglottis of the tapeworm, offers so great a resemblance to that of some of the Trematoda, that they have been regarded as identical by several recent obser- vers. In each sexual joint of the tapeworm, the testicle and the two parts of the ovarian organ coexist, and, as stated in an earlier part of this article, arrive at maturity simul- taneously in the posterior or oldest segments of the body. Van Beneden has, in his recent work on the Cestoid Wormsf , described very clearly the structure and relations of the ger- migenous and vitelligenous parts of the repro- ductive organs in the complete segments or proglottides of a variety of Cestoid worms. The ova originate in the first mentioned of these organs as germinal vesicles, and, passing into the vitelligenous part, meet with the yolk-masses formed there. Near the same place is situated the seminal vesicle, from which, doubtless, the spermatic substance easily reaches the ovum as it descends in the course of its formation. The ova then ac- quire an external envelope, and pass into the cavity termed a uterus. As they corne to be accumulated in gradually increasing quantity in the latter cavity, they distend it to a great degree, so as to cause it to pervade in various forms, ramified and others, the whole body of * See also Thaer on this subject, in Muller's Archiv., 1850, p. 626. f Mem. sur les Vers Cestoides. Acad. Roy. de Belgique, torn. xxv. 1850, see plate B. OVUM. [125] the proglottis ; and finally they are dis- charged from this, usually after the separation of the joint from the main tapeworm, by the irregular rupture of the outer wall, or by a genital aperture. Here, then, we have another instance of the combi nation of the several com- ponent elements of the ovum together with the sperm, previous to the enclosure of the whole by a membrane so as to give the form of a complete ovum. The ova of most of the Cestoidea, as in the common tapeworms, are of proportionally small size. The external envelope is firm, thick, and nearly homogeneous ; sometimes, however, presenting a slight appearance of fine radiated strias passing through it, which recalls the structure of the thick membrane of the Fish's ovum. The vitelline substance is very finely granular, or almost clear ; the germinal vesicle is perceived with difficulty, but is of large size.* In some Cestoids the external envelope is of a brown colour, as in the Trematoda, and in others presents pecu- liar forms and prolongations from its surface. A delicate vitelline membrane is described within the outer covering by some authors.f The segmentation of the yolk appears to be complete ; but this process has been observed only in a few instances. Of the ova of the Cystic Entozoa nothing need here be said, seeing that it has already been shown that the several genera of this order, viz., Cysticercus, Ccenurus, and Echi- nococcus, are only larral and aberrant forms of the Cestoid worms, and being immature animals, never produce ova, excepting through their more advanced stage of cestoid develop- ment. Echinodermata. — The different orders and families of this class are all of distinct sex, so far as is yet known, with the single exception of one of the Holothurida, viz., Synapta(S. Duvernaea), described by Quatrefages^l as presenting a combination of the testicles and ovaries in one organ, resembling in some measure that which exists in the Gasteropo- dous Mollusca. In the females of Echinus, Asterias, and Holothuria, the ova have been studied with care by different observers. In all of them the ova present, when mature, more or less of a deep yellow, orange, or red colour, which belongs to the yolk-substance. This sub- stance is finely granular, and is enclosed, at least in some, as Echinus, by a delicate vitelline membrane ; but in others, as Holo- thuria, there is a considerable deposit of an albuminous layer of a peculiar structure, which, from its adhering closely to the vitel- * See Kolliker in Mullet's Archiv. for 1843, p. 92 ; Tafl. vii., fig. 44. f Details as to the structure of these ova will be found in the work of Von Siebold in Burdach's Physiologie, vol. ii. ; in Dujardin's Hist. Nat. des Helminthes, see pi. ix. and xii. ; in Blanchard's memoirs in the Annal. des Scien. Nat. for 1848, p. 321 ; in Van Beneden's work ; and in Kuchen- meister's more recent Handbuch der Parasiteu des Menschen, &c., Leipzig, 1855. J Annal. des Scien. Nat., 1842, xvii. line membrane, obscures the latter envelope, and thus has made its existence doubtful to some observers. This albuminous deposit also exists in Echinus, but is in that animal distinguishable from the vitelline membrane.* The colour and opacity of the yolk-sub- stance in the mature state of the ovum usually prevent our perceiving the germinal vesicle ; but in the earlier stages of formation, when the ovum is of lighter colour or even quite clear and transparent, a germinal vesicle with a single distinct macula is easily per- ceived. This vesicle has disappeared in the ova which are deposited. The segmentation of the yolk is complete in the Echinodermata : the process has been fully traced by Sars in Asterias f, and by various observers in some other genera. It was in the ovum of Holothuria tubulosa that Professor Johannes Muller first made the novel and interesting discovery of an aperture leading through the thick external membrane towards the yolk ; an observation which has been confirmed by various other physiologists J, and has been productive of important con- sequences in its extension to a number of other animals in which such an aperture was not previously suspected to exist. MUller brought this observation before the Berlin Academy, and it was noticed in the printed report of the proceedings in 1851. A more detailed account of his observations on this subject is given by Muller in his Archiv. for 1854 (p. 60.). The very thick covering of the ovum of Holothuria presents an appear- ance of radiated lines running through it per- pendicularly to the surface, which resembles in some degree the marking in the membrane of the Fish's ovum, but is not so distinct, and does not appear, as in it, to be produced by visible tubes or pores passing through the membrane. The canal of the micropyle pierces the whole thickness of the radiated membrane ; but Muller conceived that it did not perforate the delicate vitelline membrane placed on its inner surface. Leydig, however, and Leuck- art are of opinion that the canal passes com- pletely into the interior of all the egg-coverings, and reaches the surface of the yolk, so that it may convey the spermatozoa to that body. The entrance of the spermatozoa has not, however, as yet been actually observed. According to Leydig, the thick membrane may consist of several layers united together, such as, internally the vitelline membrane, the thick albuminous part in the middle, and ex- ternally the nucleated layer formed by the remains of the ovarian capsule. Leuckart and Leydig have also pointed out the fact that the formation of the canal of the micropyle in the egg of Holothuria proceeds from or is con- nected with the original attached and pedicu- * Derbes, in Annal. des Scien. Nat. 1847, 3e Se'r. vol. viii., p. 80, and Leydig in Muller's Archiv. for 1854, p. 312. f Wiegmann's Archiv. 1844, and Annal. des Scien. Nat, 3e se'r., vol. ii. p. 190. J Leuckart in Bischoff's Wiederlegung, &c., 1854, and Leydig, loc. cit. [126] OVUM. lated condition of the ovum in the ovary, that it is in fact the remains of the divided pedicle after the ovum is separated from the place of its original formation. serve Ovum and Micropyle in Holoihuria tubulosa. (From Ley dig.} a, b. A small portion of the ovary from the inner surface, containing ova in various earlier stages of their development ; three of them project from the inner surface, of which a is the most de- veloped. In this one the pediculated attachment and enclosure of the ovum by the nucleated ovarian membrane is seen, the yolk granules and the ger- minal vesicle with its macula. c. A more advanced ovum now separated from the ovary. Externally the nucleated remains of the ovicapsule are represented ; inside this the thick albuminous layer marked with radiated lines, and lined closely by the vitelline membrane ; both these, as well as the ovicapsule, being perforated by the micropyle formed at the place where the pedicle formerly existed. The micropyle "aperture has also been ob- irved in other Echinodermata, viz. by J. Mliller in Ophiothrix fragilis, in which he states its diameter to be yaW* anc* by n*s son Max Miiller in Sternaspis thalassemoides.* This aperture has not yet been observed in the ovum of Echinus. In the fecundated ova of this genus, however, Derbes observed spermatozoa to have passed through the thick external albuminous covering, but not within the more delicate vitelline membrane ; but in this animal the external covering is more like a layer of soft albumen than a dense mem- brane as in Holothuria. The ova of Echinodermata take their origin, like those of other animals, by the formation of the germinal vesicles. These have been * The micropyle was represented in the ovum of Holothuria tubulosa by R. Wagner in his Icones Zootomicae, tab. xxxii., fig. 12., before its nature was known. The first discovery of a micropyle in the animal ovum is therefore due to J. Miiller. The next observations of a similar nature are those of Leuckart and Keber. observed by Leuckart in the Holothuria tu- bulosa, beginning to be formed in the ovarian substance, which they cause to bulge or pro- ject when they enlarge, so as to hang into the ovarian cavity. The yolk-granules then come to be deposited round the vesicles, rendering the ova opaque, but during all this time the ovum is attached and enveloped by the original capsule derived from the ovary ; the albu- minous layer is then deposited, and the ovum being detached, the micropyle remains, as al- ready stated, as the perforation in the pedicle of attachment.* Polypma. — Although the greater number of the Polypi are commonly multiplied by a process of gemmation, as has already been stated in a former part of this article, yet they are all capable of attaining sexual complete- ness, and are also reproduced by means of fecundated ova. From the varieties, however, presented by the form both of the gemmules and true ova in different genera of Polypes, considerable difficulty has been experienced in determining the exact circumstances in which the ova are produced, and the distinc- tion between the germs from which true ova and those from which gemmae are formed. This is more especially the case among the ciliobrachiate Polypes or Bryozoa, which in their general organisation approach very nearly the tunicate Mollusca, but which in their mode of reproduction resemble closely some of the Polypes. The ova of the common Hydca, already re- ferred to in a previous part of this article, present the character common to the class, of being enveloped by a firm covering or shell membrane, which seems to be formed from modified cells, and which is sometimes beset with rough processes or projecting bristles or barbed spines somewhat like those of the Bryozoa. In the Tubularidae and Sertularidae the ova are formed in ovigerous capsules, which may be regarded as modified individuals or polype-heads of the compound animal formed by gemmation. In some instances these are detached from the parent stem, as in Tubu- laria indivisaf ; in other genera they remain attached, and their ova, or the ciliated em- bryos developed from them, are discharged from the cavities in which they are formed J ; but as the phenomena of the production of these ova have been fully described by Pro- fessor Rymer Jones in the article POLYPIFER A, it is unnecessary to enter into farther details with regard to the process in this place. * In addition to the memoirs previously quoted, descriptions of the ova of Echinodermata will be found in the following : viz., those of Comatula by J. Muller, in Mem. of the Berlin Academy for 1841 ; of Asteracanthion, in Wagner's Prodromus, and in the 5th Part of Carus and Otto's Tabulae Anat. Compar. ; those of Echinus by Derbes, loc. cit. ; and by Krohn in Beitr. zur Entwick. der Seeigel- larven, Heidelberg, 1849, &c. f Sir John Dalzell, Remarkable Animals of Scotland, &c. J Dumortier and Van Beneden's Researches, in Mem. of the Acad. of Belgium, 1842, torn. xvi. OVUM. In Hydractinia rosea, Van Beneden ascer- tained the existence of the germinal vesicle and nucleus within the ova while still con- tained in the capsule ; and it appears that in all true ova of the Hydrozoa the vitellus, which consists of finely granular substance, undergoes a complete segmentation in the same manner as in other animals in which it presents a similar structure. In the common fresh-water polype, in which ovigerous capsules, or ova, and spermatic cap- sules were found coexistent on the same in- dividuals, I observed sometimes the spermatic capsules brought into contact with the surface of the ova by the bending round of the body of the polype at the time when the spermatozoa were being discharged. This took place pre- vious to the formation of the firm external covering ; but I could not determine whether fecundation had thus taken place or whether any spermatozoa had penetrated the ovum. In some of the Hydrozoa, as in the com- mon green polype, the ova are single, while in others as in thdra fusca, figured by R. Wag- ner*, there are several ova enclosed in the same capsule. It is remarkable that, while in some Hy- drozoa the ova are developed from animals which retain the polype form in their com- plete sexual condition, or from modified po- lype heads, in others, as in Coryne, Fritil- laria and Campanularia dichotoma, it is only from a medusoid progeny separated from the polype stock that the true fecundated ova are produced. In Anthozoa, the most of which, as Actinia, Alcyonium, Veretillum, Gorgonia, and the Corallines are hermaphrodite, the ova consist of finely granular yolk, germinal vesicle and macula, and undergo complete segmentation. The Bryozoa may be most appropriately considered in this place, as they present con- siderable analogy to the compound polypes in the mode of their reproduction. They are of separate sexes, and appear to be propagated in three modes, viz. : 1st, by gemmation ; 2nd, by true fecundated ova ; and Srdly, by bodies which have long been regarded as ova, but which according to Professor Allman's recent researches may rather be considered as peculiar encysted gemmules, and may pro- bably be analogous to the so-called winter ova of Daphnia and Lacinularia to which reference has previously been made. The development of the true ova of Pedi- cellina observed by Van Beneden has been already described.f In this instance the ova are arranged in clusters surrounded by a transparent capsule. In each ovum the finely granular yolk undergoes a complete segmen- tation. The germinal vesicle possesses a sin- gle macula. According to Van Beneden and Dumor- tierj, the ova of Alcyonella are developed in ovarian sacs connected with the inner end of * Icones Zootomicae. t See p. 23. and Jig. 19. of this article. t Mem. sur les Polypes d'Eau douce. Acad. de Belgique, 1812. the stomach. They are described as com- mencing by the formation of germinal vesicles with nuclei or maculae, and as having subse- quently the granular yolk-substance deposited round each vesicle ; and these authors de- scribe the same ova as acquiring at a later period the peculiar horny or cellular covering which forms the two-valved shell membrane long known as belonging to the winter ova of this and several other genera of fresh- water polypes. But with regard to the na- ture of these bodies and the mode of their formation some doubts may arise in conse- quence of the researches of Professor Allman. The bodies in question are at first nearly spherical and of a light or milky colour ; they become later of an oval form, and flattened or discoid, and the cells of the shell -covering are then developed, and acquire the deep brown colour which very generally prevails among these bodies when arrived at maturity, and which makes it impossible to trace farther the changes within the ovum. These cells are developed to a greater extent round the widest margin of the disc, so as to form there a thick ring or border, which is afterwards cleft in two when the valves of the shell open to allow the escape of the embryo. The same authors have described the pro- pagation of the Paludicella to take place in summer by means of buds, and in winter by Fig. 92*. Formation and Structure of the ova of Lophopus Bakeri. (From Van Beneden.) These represent, according to Professor Allman, not the true ova, but the Winter ova or " Stato- blasts." a. The ovum previous to the deposit of the cellular covering and marginal plate, b. This co- vering now in progress of formation, c. and d. pro- file and front view of the ovum, when completed, showing the structure of the cellular border which is afterwards cleft in two at the edge, when the em bryo is about to escape. e. An ovum at an earlier stage showing the ovi- capsule in part removed from one side of the ovum and its cellular covering. [128] OVUM, means of true ova, as well as by attached buds, which last are then covered by a strong corneous envelope, and have received Fig. 93*. winter ova, or the bodies provided with the corneous envelope, are formed chiefly towards the autumn and winter season ; and the strength of their covering has generally been re- garded as a provision for the protection of the germ from the hurtful influences of the winter season. During two seasons I have observed the production of these bodies from the Plu- matella repens ; and I have kept them through the winter till the polypes were developed, and issued from them in the ensuing summer. From his careful observation of these bo- Fig. 94*. Formation of buds in Paludicella. (From Van Beneden and Dumortier.) a. One of the Polypes of Paludicella Ehrenbergii contracted within its cell, showing at the upper part towards the right the commencement of the formation of the bud by the growth of cells be- tween the outer and inner layers of the cell-wall. b. The same bud a little more advanced and more highly magnified, represented by itself. The vesicular cells which separate the ectocyst and en- docyst are seen more distinctly. c. A more advanced stage of the same, internally ; the part from which the embryo polyped arises is seen bulging out from the rest. This figure has been introduced to show the difference between the process by which a true bud arises and that by which ova are produced. the name of propagula. In Fredericella they describe a propagation by means of buds and by ova provided with the strong horny envelope. In Alcyonella and Lopho* pus, besides the usual propagation by buds, and by the common ova, these authors have stated that there is also a viviparous produc- tion of ciliated embryos from ova which re- main within the parent animals ; but they have not stated particularly the manner in which these ova originate, nor their difference from those which receive the corneous en- velope. The difficulties presented by these varieties seem to be in some measure re- moved by the view offered by Professor All- man of the nature of the bodies last men- tioned, to which I will now advert. It has Ions been known that the so-called Winter ovum and embryo of Lophopus Crystallinus, (From Van Beneden and Dvmortier.) This is the same as that represented by Turpin under the name of " Cristatella mucedo." In A. the flat surface, and in B, the narrow edge of the ovum, is represented. The two valves of the egg cover- ing have opened superiorly, and the embryo, which already possesses three crowns of tentacles, is seen escaping. dies in several genera, Professor All man has arrived at the conclusion that they are not, as was previously supposed, true ova, but rather separated gemmules; and he conceives that Van Beneden, who has described their form and structure so well, must have confounded them with some other bodies in their first or earlier stages, or has failed to distinguish be- tween them and the true ova. This distinc- tion Allman has succeeded in making by as- certaining that the true ova and these bodies do not arise in the same situation, and that these winter ova or gemmules do not in their earliest stages present any germinal vesicle or macula as the true ova do, and do not after- wards undergo any segmentation. They are formed, according to Allman, in the funiculus which connects the bottom of the stomach with the inside of the cell of the polypide, the same body which was described by Van Be- neden and Dumortier as an ovary, but which Allman regards rather as analogous to the gemmiferous stolon of the solitary Salpae. These bodies Professor Allman proposes to call stato- blasts. He farther discovered that there is a true ovary with genuine ova which may be distinctly observed in Alcyonella, and which is situated in the walls of the endocyst OVUM. [129] near the anterior extremity of the cell. A number of ova were found in the ovary con- taining the distinct germinal vesicle with macula. He also observed the segmentation of these ova in the usual manner, and the conversion of the segmented mass into a ciliated embryo, within which the new polype is subsequently developed.-f- Should these observations prove correct and be applicable to the other instances of similar winter ova among the Bryozoa, they may tend to remove some of the difficulties which exist in regard to the various repro- ductive bodies occurring in these animals ; but farther researches seem still necessary to point out in these and in other polypine ani- mals more fully and minutely the relation be- tween the three kinds of reproductive bodies, viz., true ova, separated gemmules, and at- tached buds. AcalephcB. — It is remarkable that notwith- standing the very close relation in which these animals stand to the Anthozoid Polypes, the form of their ova is not the same. The Dis- cophora (Medusae) are of distinct sexes : the Ctenophora (Beroes) are hermaphrodite ; the Siphonophora (Diphyidae) are various, or bear, in the manner of compound animal stocks, a variety of zoids, sometimes of one sex alone, at other times of different sexes on the same stem. The structure of the ova in Medusas is extremely simple. They are originally formed from minute cytoblasts which soon acquire a single nucleus or macula, and are enclosed in a delicate external membrane. These consti- Fii*. 95*. Development of the ova of Acalepha. These figures give magnified views of the diffe- rent stages of formation of the ova taken from the ovary of a large Rhizostoma. a. The primitive germ. b. The germinal vesicle now present in the primitive ovum. c. d. The same more advanced and enlarged, the macula has appeared in the ger- minal vesicle, and a few yolk granules are deposited in the clear vitelline substance, e. The yolk gra- nules greatly increased in quantity and becoming opaque, a vitelline membrane is now formed, f. The same somewhat more advanced, the yolk gra- nules are now collecting together to form cor- puscles. The macula is assuming the elongated form. t Proceedings of British Association for 1855. See also Professor Allman's interesting Report on the Polyzoa to the British Association. See Trans, for 1850, p. 320. Supp. tute the germinal vesicles, round which the granular yolk-substance is gradually deposited in increasing quantity. The complete segmen- tation of the yolk has been observed by Von Siebold in Cyanea aurita.* The yolk-sub- stance is often highly coloured, violet or yellow. In the former part of this article I have referred to the manner in which some compound Hydroida are propagated through their medusoid progeny. These medusoid individuals, like the ordinary Medusae, are of separate sex ; and they must therefore be looked upon as the complete stage of the polypine animals from which they have proceeded, whether they have their young developed while the parent remains at- tached to the nursing polype stock, or have assumed the separate and independent mode of life in a more complete state of develop- ment. There are many varieties in the de- gree of perfection to which they attain even while remaining attached to the polype ; but the general principle of formation is the same throughout the whole of the hydroid animals, the remarkable and constant fact with regard to the mode of their reproduction being this, that the immediate product of development from the ovum which has been formed by sexual generation from a Medusa or medusoid animal is invariably an attached Polype, and that the medusa or medusoid is the product of a non-sexual process of gemmation from this polype stem. Protozoa. — With regard to the Protozoa, or Infusoria and Rhizopoda, it is unnecessary to add anything here to what has been stated in the several articles on these subjects and in a former part of this one, excepting the remark, that continued researches appear to show that as the sexual distinction has not been de- tected, and may probably be absent in these animals, the nucleus of the monocellular forms of these beings may hold the place of the germinal vesicle in them, and that the processes of division and production of in- ternal gemmules takes the place of true ovu- lation. At the same time it must be admitted that it is by no means improbable that the sexual relations may yet be discovered in the lowest monocellular animal bodies, as has re- cently been the case in some of the simpler and monocellular Alga?, and that as our knowledge of the process of reproduction in these beings is still very limited, it may be destined to un- dergo even greater progressive changes than those which it has suffered from the researches of the last few years.f Porifera. — The bodies which have usually been regarded as the ova of Sponges, and to which a reference was made in the earlier part of this article, are of two kinds, viz. gem- mules or detached ciliated portions of the * Beitr. zur Naturgesch. der Wirbellos. Thiere, 1839. f See the papers of Focke, Cohn, and Stein re- ferred to in the first part of this article, and the more recent work of Stein, "Die Infusionsthiere auf ihre Entwickelungsgeschichte untersucht." 4to. Leipzig, 1854. M [130] OVUM. substance of the sponge, and certain spherical bodies enclosed by dense capsules, which are produced towards winter, and which appear to contain a number of germs, each of which is capable of being developed into a Protean animalcule, from which probably a sponge may proceed.* But it may be doubted whe- ther these last-mentioned capsules are true ova or may not rather be of the nature of the gem- mules, winter ova, or statoblasts of Professor Allman; and it is important to notice that Mr. Huxley has recently discovered in Te- thya a different set of bodies, which contain all the essential parts of true ova, viz. vitel- line membrane, yolk, germinal vesicle, and macula, and that these bodies, which are si- tuated between the cortical and central sub- stance, are imbedded in a mass of cells together with spermatozoa.f Although the individual living particles of the sponge closely resemble simple ciliated infusoria, and the mass may, therefore, be viewed as an aggregate of these minute beings, yet its analogies with and transitions towards the fungiform polypes are so great, that we may expect ere long that the phenomena of its reproduction may be placed in a new and clearer aspect by the continuation of the researches now noticed, and by others of a similar kind. RECAPITULATION AND CONCLUSION. Having now stated in detail the principal facts that have come under our knowledge with regard to the form, structure, and mode of origin of the ova of different animals, it may be proper, in bringing this article to a close, to endeavour shortly to deduce from these facts the most general results to which they appear to lead. These results, together with some re- flections on our subject, may be stated under the following heads, viz. 1. Definition of the ovum, as related to its own structure, and its history in connection with the reproduction of the species. 2. Recapitulation of the most general facts ascertained by the comparison of the ova of different animals. 3. Morphology of the ovum ; homology of its parts; and rela- tion of the ovum to other organic structures. 4. Phenomena attendant on the maturation of the ovum. 5. Relation of the ovum to fecundation by the male sperm. 6. Immediate effects of fecundation on the ovum ; and re- lation of the ovum after fecundation to the first commencement of the process of em- bryonic development. 1. Definition of the ovum, as related to its own structure, and its history in connection with the reproduction of the species. In the commencement of this article the ovum was shortly defined as " the product of parental sexual generation from which the young of animals are developed (produced)." This definition appears correct and sufficiently comprehensive ; but should it appear desirable to substitute for it a more precise description of the characteristics of the animal ovum, the * See Carter in Annals of Nat. Hist. vol. iv. p. 89. f See Mr. Huxley's paper in Annals of Nat. Hist., 2nd series, vol." vii. p. 370. following may be proposed as applicable to the ovum throughout the whole animal king- dom, without involving any merely theore- tical view of its structure and constitution, viz. " the ovum may be shortly described as a detached spheroidal mass of organised substance, of variable size, enclosed by a vesicular membrane, and containing in the earlier periods of its existence an internal cell or nucleus ; these parts, formed by the female individual or organ of animals, are capable, when fecundated by the male sperm of the same species, of giving rise, by the series of histogenetic and organogenetic changes known under the general term of develop- ment, to an embryo, from which either directly or mediately the individuals of the animal species to which the parents belong are re- produced." We thus separate from the category of true ova all those bodies of an apparently reproductive kind which are not the direct product of an act of sexual generation. To such bodies, the nature of which is as yet doubtful, and probably somewhat various, the indefinite appellations of buds, bud-germs, gemmae, spores, winter ova, ephippial ova, statoblasts, &c., have been given according to the circumstances in which they are se- verally produced. In all animals, then, with the exception of the Polygastric Infusoria and Rhizopoda, the occurrence of sexual generation and the for- mation of true ova are proved to be the regular and constant means for the permanent reproduction or maintenance of the species. In the exceptional instances now mentioned, and even in some others possessed of the sexual distinction, the best known and most common multiplication of individuals takes place by a subdivision of the parent body, either by fissiparous cleaving or by gemma- tion; but in them also it can scarcely be doubted that there are other means by which the permanence of the species is maintained. All the most accurate recent investigations lead to the conclusion that the production of the young of all organised beings, even the simplest of the Protozoa, does only occur by direct connection through some organised medium with other beings of a similar kind or species. We are forced, therefore, to con- clude that in the propagation or production of these simple beings, in circumstances where their more ordinary fissiparous or gemmi- parous mode of multiplication cannot be ad- mitted to have taken place, there must have passed from the bodies of the progenitors minute particles of organised substance (ca- pable, as we know, of being suspended in the atmosphere, and of resisting during a long period many of those influences which gene- rally prove inimical to animal development), which particles, when brought into circum- stances favourable to the progress of the vital processes, undergo the cycle of changes ne- cessary for the reproduction of beings similar to those from which they sprang. If there is any constant law which seems more certainly OVUM. [131] than others to result from all recent researches into the history of organic nature, it is this necessary connection by descent of one being or set of beings from another. In all animals, with the exception of the simplest tribes already referred to, the descent from parent to offspring is through a product formed and perfected only by the concurrence of male and female organs ; but we are still at a loss to determine whether the unseen germinal bodies by which the Protozoa are reproduced are of the same or of a different nature. The structure of some of these ger- minal bodies as described in the earlier part of this article (p. 7., &c.), bears a very great resemblance to that of true ova ; but yet the sexual distinction of the parent animals has not yet been discovered. The recent re- searches of naturalists indeed show that our whole knowledge of the history of the Pro- tozoa may be considered as only in its infancy. The discoveries as to the encysted stage of existence among the Vorticellae and Gre- garinae and others, the phenomena of conju- gation observed in Gregarina and Actino- phrys, the entire knowledge lately gained of the form, structure, and habits of the Fora- minifera, all point to important future dis- coveries and modifications of our hitherto crude and imperfect views of these tribes of beings, and must make us refrain from at- tempting at present to form any opinion or even conjecture as to the modes of their re- production ; while at the same time the recent discoveries as to the existence of the sexual distinction in the simplest forms of plants encourage the hope that ere long the repro- duction of the Protozoa may, in a similar manner, be removed from the obscurity in which it now lies hidden. It does not appear necessary from these considerations that our definition should make any direct reference to animal bodies of the nature of which our knowledge is still so imperfect. The result of development from a fecun- dated ovum in all vertebrate and in a con- siderable number of invertebrate animals, is the formation of an embryo which, by a pro- cess of progressive growth, arrives at matu- rity, and assumes the form, structure, and habits, either, as the case may be, of a her- maphrodite animal, or of the parent of either sex. In a certain number of these instances, as in Batrachia, Insects, Crustacea, and others, growth is not altogether continuously pro- gressive, but is subject to one or more breaks or changes as it were, which are marked by some change in the mode of life, or some difference in structure of the individual. To such marked changes in the course of the development or growth of an individual ani- mal proceeding from a fecundated ovum, the name of Metamorphosis is given. But from the facts narrated in the earlier part of this article, it appears that in a cer- tain number of the invertebrate animals, such as those which have been referred to under the heads of Echinodermata, Polypina, Aca- lepha, Tunicate Mollusca, Trematode and Cestoid Entozoa, Annelida and Insecta, a very different result may, either regularly and constantly in some, or only occasionally in others, attend the first development from the fecundated ovum. To this modification of the developing and reproductive process the appellations of Alternate Generation or Meta- genesis have been given, of which terms the latter may perhaps be the most appropriate. The phenomena which have been described under this head are so very various, that it is difficult, if not impossible, to give a short and general statement of their nature. The dif- ference between this and the better known form of direct generation may, however, be stated nearly as follows : — In the Metagenetic form of reproduction the individual formed by the development of the fecundated ovum is generally different in aspect, structure, and mode of life from the parent or parents by which the ova were produced ; this individual, or zoi'd, though possessed, in many instances, of an organisation and of powers which fit it for the efficient performance of many of the most important acts of independent animal existence, is yet wanting in the attribute of perfect animal maturity, viz., the sexual or- gans and activity, and is consequently incapa- ble by itself of an act of true generation, or, in other words, of the formation of fecundated ova, by which alone the species can be per- manently reproduced. In such instances, then, it is only by the formation from these intermediate beings of others which are sexu- ally perfect, that the generative act can be repeated. There are two phenomena re- quiring to be distinguished in connection with the most common forms of this process ; the one the frequent multiplication of the im- perfect intermediate beings, or zoi'ds ; and the other the production either directly or by a succession of acts of development from the intermediate beings of those which are sexu- ally perfect, or which resume the form be- longing to the parents from which the fecun- dated ova were derived. It seems proper, therefore, to distinguish between an act of true sexual generation, and that by which new beings are formed from the intermediate individuals (or so-called nurses of Steen- strup, or zoi'ds of other authors) ; the first consisting invariably in development from a fecundated ovum ; the second being probably more analogous to a process of budding or gemmation from a parent stock. It must be confessed, however, that we have still much to learn regarding the phenomena of this pro- cess, before we can form any general notion of its nature. The whole subject is replete with the deepest interest not only in connec- tion with the history of reproduction, but in its influence, as stated in some parts of the preceding article, on the whole range of zoo- logical classification and distinction. Our extended definition comprehends an allusion to these phenomena. Lastly, the ovum may be considered as having two phases or stages of existence ; the one in connection only with the female [K21 [132] OVUM. parent or female organ, in which the greater part of the organised material first to be employed in development is provided, and in which the ovum arrives at a certain stage of maturity ; and the other in its relation to fe- cundation, or to the influence of the product of the male by which its developing powers are awakened or called forth. The mature ovarian ovum may therefore, in one sense, be looked upon as complete, if we regard only its own structure ; but here its progress would be arrested without the occurrence of fe- cundation, and if we view it, therefore, with reference to its more important destination as the means of continuing the animal species, the ovum can only be regarded as perfect when that hitherto inscrutable change has been effected on its substance by admixture with the minute elements of the sperm in fecundation. The constancy of this law in the whole animal king- dom, with the exception of those of the Pro- tozoa already referred to, makes it proper that our definition should make reference to fecund- ation as the means of perfecting the ovum. To the nature of this process itself a further al- lusion will hereafter be made. 2. Recapitulation of the most general facts ascertained by the comparison of the ova of different animals. The ova of animals in their complete state may be considered as consisting ot two sets of parts which are of very different relative importance in connection with the develop- ment of the embryo : the first of these sets of parts belong to the ovarian ovum, and are formed previous to their quitting that organ ; the others are subsequently formed, and may be looked upon as accessory. These last often present great varieties, so as to cause the ex- ternal form and appearance of the ova of ani- mals to differ widely, while the ovarian part much more nearly corresponds. To this ovarium ovum we shall principally confine our present remarks. An extended comparison of the ovarian ova of animals belonging to almost every family of the animal kingdom has shown that, notwithstanding great differences in size, and some variation in form and structure, they all agree in consisting of three essential and nearly similar parts before the period of their detach- ment from the ovary : these are, 1st, The in- ternal nucleated cell or germinal vesicle with its macula or maculae ; 2nd, The vitellus, or yolk-substance ; and 3rd, The enclosing vesi- cular envelope, or vitelline membrane. In all animals there is, also, a general similarity in the manner in which these parts are formed and combined so as to constitute the ovarian ovum ; the germinal vesicle is the first produced, and may be regarded as the ovigerm ; the yolk- substance next gradually envelopes it or is deposited round the germinal vesicle, and in general the vitelline membrane which encloses the whole is the latest formed. The most marked differences among the ova of animals are connected with the struc- ture of the yolk and the relation which it bears to the formation of the germinal part out of which the embryo is afterwards developed* Founding upon this difference, three groups' two principal and one subordinate, may be distinguished among the ova of animals: — 1st, The group of small-yolked ova, to which belong those of Mammalia and a considerable number of invertebrate animals, such as most Mollusca, the lower Crustacea, most Anne- lida, the Entozoa, Rotifera, Echinodermata, Acalepha, and Polypina. In this group, the ovum is generally of small or of moderate size, as a whole ; the vitelline substance con- sists entirely or chiefly of fluid with fine gra- nular particles, and the entire yolk undergoes segmentation : the entire yolk mass, therefore, is directly formative, or is employed from the first in the formation of the blastoderm or organised substratum in which the embryo is developed : the germinal vesicle is in this group usually of small size, and has only a single macula, or one composed of very few particles. The second principal group comprehends the large-yolked ova, such as those of Birds, Scaly Reptiles, Cartilaginous Fishes, and the Cephalopoda, to which, perhaps, may be added Insects, Arachnida, and most Crustacea. In this group, the largely developed yolk contains, suspended in its basement, homogeneous sub- stance, two kinds of organised corpuscles, viz., 1st, A certain portion of the small granular part, similar to that of the small yolked ova, which occupies a limited but determinate place in the ovum, and in its centre the germinal ve- sicle is situated ; and 2nd, A larger portion of spherules, cell-like or other corpuscles of greater magnitude. It is the first or finely granular portion only which is immediately germinal, or which is subject to segmentation and forms the basis of the blastoderm ; the remainder, or large cellular portion, is only secondarily employed in supplying nourishment to the embryo or its accompanying organised parts in the progress of their development. In the ova of this group, therefore, we distinguish the formative or directly germinal portion of the yolk-substance from the indirectly nutritive portion. In these ova, the germinal vesicle is also proportionally large, and the contents of the vesicle, though consisting in the earliest stages of their formation of a single macula, or of a very small number, very soon become converted into very numerous maculae, or into a fine granular pulp. The third, or subordinate group, may com- prehend the ova of Amphibia, or scaleless rep- tiles, and osseous fishes, to which, perhaps, may be added some of the invertebrate ani- mals mentioned under the second group. The ova of this group are intermediate in their structure between those of the first and se- cond : they have certainly the greatest affinity with the large-yolked group, but there are many gradations among the ova of this kind, among allied species of animals, and it is chiefly on the ground of the incompleteness of the segmentation that I have thought it proper to arrange them in a separate group. It may be remarked further, that in all ani- OVUM. [133] mals, whatever may be the ultimate structure of the yolk, the primitive yolk, or that which is first formed, is invariably of the finely gra- nular kind, — the cellular or large corpuscular yolk-substance is of later formation. These two parts remain distinct from each other, and the finely granular or formative yolk is that in which the germinal vesicle is invariably im- bedded. In those instances, such as the Bird, Reptile, &c., in which the large cellular yolk greatly preponderates over the formative yolk- substance, the latter assumes in the later stages of formation the shape of a flatfish disc on one side of the greater mass of the yolk, with the germinal vesicle placed in its centre. The vitelline membrane presents some va- rieties in structure, being in some animals very delicate and homogeneous; in others, as Mammalia, remarkably thick, tough, and elastic, but without visible structure ; in a third set, exhibiting peculiar structure, such as the finely tubular perforations of the ex- ternal membrane of the fishes' ovum, or the radiated markings in the ova of Holothuria or Cestoidea ; but in these last three in- stances the vitelline membrane is probably associated with additional layers of substance derived from a different source from that which forms the homogeneous membrane. A remarkable peculiarity has recently been discovered in the enclosing membrane of the ovarian ovum of some animals, in the aper- ture or micropyle which has been observed in osseous fishes, insects, some Crustacea*, the Acephalous Mollusca, some Annelida, Holothuria, and some other Echinodermata. There seems reason to believe that a similar aperture exists in the ovum of Batrachia and Cephalopoda ; and it is very probable that it may yet be discovered in other animals. At the same time it is right to state that in Mammalia and several other animals it has been most carefully sought for without suc- cess. This aperture appears to be designed to admit the spermatozoa into the cavity of the ovum, or into contact with the yolk-sub' stance and germ, in those instances especially in which the egg coverings are thick and touiih, and fecundation is late of occurring. The relation of the ova to the ovaries or organs in which they are produced, exhibits considerable varieties in different animals. 1. The most common is that in which the germs of the ova arise within minute close follicles or vesicles, which are imbedded in the more or less solid or loose stroma of the ovary ; the follicle enlarging with the ovum as its other parts are added till the period of of maturity, when, periodically, the follicles open for the escape of the ova. 2* In a second form, as in Nematoid Worms and Insects, the germs of the ova are produced free in the upper part of an ovarian tube, * It has been inadvertently stated in a preceding part of this article (p. 116.) that the micropyle had not been observed in the ova of Crustacea, whereas Meissner has ascertained its presence in that of Gamraarus. (See his Memoir in Zeitsch. fur Wissen. Zool. vol. v. p. 284.) and the yolk-substance, &c. are added gra- dually as the egg germs descend through suc- cessive portions of the tube : here no true de- hiscence is necessary to allow of the escape of the ova. 3. In a third form, as in Trema- tode and Cestoid Entozoa, distinct organs are provided for the formation of the ovigerms and the yolk-substance, and these last are brought together and combined into the sphe- rical form of an ovum in another part of the genital apparatus. 4. In the greater number of animals the germs for each ovum appear to arise singly, and the ova are thus isolated from the first ; but it would appear that in some animals these germs arise in groups, perhaps by development from a common germ, so that they are from the earliest period connected together by pedicles. Yet, with all these differences, there is to be perceived, on the whole, a general similarity in the plan of formation of the parts of the ovum itself in different animals. This plan may be generally stated as follows. The germinal vesicle is universally the first part of the ovum which makes its appearance ; it does not appear to be nucleated or to pos- sess its macula from the first in all instances, and this macula cannot therefore be regarded as the centre of its formation. The germinal vesicle is generally at first only a minute point ; it soon enlarges, however, and either possesses from the first, or at a very early period acquires, its macula or nucleus. In animals with the solid follicular ovary, each follicle is occupied by a single ovum, which begins within it as a minute germinal vesicle. The delicate wall of the follicle is also per- ceptible at the same time as the ovigerm ; in- deed, there is reason to believe that it even precedes the commencement of the formation of the ovum, though this is a point not yet fully determined. In those animals, on the other hand, in which the ovary is tubular, the ovigerms appear, in some instances at least, to arise in groups within cells ; and it may be a question whether these cells bear to the ovi- germs arising within them the relation of the ovarian follicles of solid or closed ovaries. Whether this be so or not, that relation is in most instances speedily changed, as the ova soon become free, or, in others, are attached by a pedicle to a common stalk. The wall of the ovarian follicle consists at first of an extremely delicate vesicular mem- brane, which is the same as that to which the name of ovicapsule or ovisac has been given* At a very early period, and while the ovum con- sists of no more than the germinal vesicle, the homogeneous wall of the follicle is lined with a layer of flat cells somewhat analogous to some forms of epithelium : this is the com- mencement of the structure which in Mam- malia afterwards forms the tunica granulosa, and the fluid and cellular contents of the Graafian follicle. It appears to have various destinations in different animals. The second stage in the formation of the ovum is the deposit of the vitelline substance around the germinal vesicle. In most ani- mals the yolk-substance, when it first begins [K31 [134J OVUM to be formed, is scarcely granular, and in some instances quite clear, consisting of a viscous blastema, and as it increases separating the ger- minal vesicle within from the ovarian follicle, which expands proportionally. Very soon, however, and in many animals indeed from the first, fine opaque granules make their ap- pearance, as if by precipitation or deposit, in the clearer basement substance, and thus the primitive yolk-substance of the ovum in all animals is formed. In most instances there is a time during which the ovum, consisting of germinal vesicle, with a small quantity of primitive yolk, exists, without any other co- vering than that given to it by the ovarian follicle ; but as the deposit of the finely granular yolk increases, and at a very variable period in different animals, the vitelline mem- brane is formed round its exterior. The ad- dition of this covering may be regarded as the third stage in the formation of the ovum. The manner of the origin of the vitelline membrane has not yet been accurately ob- served ; and it is probable (as will be hereafter stated) that the coverings known under this name may have different modes of origin ; but if we restrict our attention at present to such simple ova as those of Mammalia, I believe it may be stated as extremely probable that the so-called zona pellucida which constitutes the vitelline membrane of the Mammiferous ovum, takes its origin by the consodidation of the superficial part of the basement substance of the primitive yolk. It appears probable that in the large-yolked ova, such as those of the bird, the vitelline membrane, which we find enclosing the whole mass of the yolk, owes its origin to a dif- ferent source ; and I am inclined to believe that in this and in many other animals the membrane which we term vitelline, as being the immediate investment of the yolk, is not of the same nature with the zona pellucida, or the simple homogeneous vesicle of the smaller ova, but rather a structure of later formation, which owes its origin to the fusion, or amalgamation, or to some other change in the outermost layer of cells which form the nutritive yolk of these animals. In connection with this view, it is import- ant to remark, that at that earlier stage of formation of the bird's egg when it consists entirely of formative or primitive yolk, there is an approach to the formation of a zona, in the existence of a very distinct, clear, and consistent marginal portion of the yolk blas- tema, from which the yolk granules seem to retire. When the large cellular or nutritive yolk is formed, this temporary zona seems to disappear, and to be replaced externally by the permanent vitelline membrane already mentioned. In those animals in which the ovigerms arise by development within cells so as to be connected in groups (Gordiacei), and in some others, the vitelline membrane, or a substitute for it, seems to be formed from the earliest period in a different manner from that now described. The germinal vesicle is unimacular in ge- neral in the small-yolked ova, and multima- cular in the large-yolked ova, and also in the intermediate kinds. In the latter it is rare to observe the earliest stage in which the ma- cula is still single : the multiplication of the maculae takes place with remarkable rapidity, and apparently by a process of endogenous development, or possibly by division. The ultimate destination of these macula is still a subject of doubt. 3. Morphology of the ovum ; homology of its parts, and relation of the ovum to other organic structures. Should the views be correct which have now been stated with regard to the relations of the parts in the mature ovarian ovum, and the manner in which they are formed, it will be apparent that a strict homology or ana- tomical correspondence can be pointed out in regard only to some of the parts which are recognised under similar designations, as re- spectively belonging to the ova of different animals. All physiologists will probably be disposed to look upon the germinal vesicle or ovigerm as corresponding or homologous in the ova of all animals, and, notwithstanding the great differences known as to its more simple or multiple condition, the same view may also be taken of the structure known as nucleus or macula. The primitive or finely granular yolk-substance, more especially that which immediately surrounds the germinal vesicle, and is afterwards employed in the formation of the blastoderm or embryogerm, seems also to have a similar origin, structure, and relation in all animals. But beyond this it is more difficult to trace the homological correspondence ; for under the names of cellular yolk-substance and vitelline mem- brane it appears that there have been brought together parts of which the origin, structure, and relations may be dissimilar in different animals. There seems at least to be sufficient reason, from what is already known of the varieties of the enclosing membrane, or so- called vitelline membrane, to establish a dis- tinction between several forms of that struc- ture; as, for example, between the vitelline membrane, which exists from the earliest period as a pediculated sac in connection with the ovarium, as in Holothuria ; that which is derived from the extension of the wall of the original germ-cell in grouped ova, such as have been described by Meissner in Gordiacei ; that which is later formed round the ovum of Mammalia as a zona pellucida, by the consolidation of the outer layer of the primitive basement substance of the yolk ; and that which in the bird and other animals whose ova are similarly constituted, appears to derive its origin in part, at least, from coalesced cells corresponding to those of the tunica granulosa of the ovarian capsule on the exterior of the cellular yolk. With regard to the cellular yolk itself, we must refrain from any attempt to establish its homology till we shall be more fully ac- quainted with the mode of its production ; for it is still undetermined whether it arises by cell formation within the primitive vitelline OVUM. [135] membrane through some change in the sub- stance of the primitive yolk, or whether it is derived, as I am inclined to believe may be the case in birds and some other animals, in a space external to these parts, and more in connection with the cellular contents of the ovarian follicle. In limiting, then, our comparison to the parts of the ovum in a bird and a mammifer, we may regard the germinal vesicles as homo- logous in both ; the finely granular germinal disc of the bird's ovarian egg as homologous with the whole vitellus of the maminiferous ovum ; the zona pellucida of the mammiferous ovum as temporarily represented by the clear outer band of the primitive yolk, which is seen in the bird's ovarian ovum when of a diameter of from T\j to 2\y of an inch ; the cellular yolk of the bird's egg, and its enclosing vitelline mem- brane as probably homologous with the fluid and granular contents and lining tunica granu- losa of the ovarian follicle of the mammifer, and not by any means with the corpus luteum of a later period, as has been suggested by some. The albumen of the bird's egg has its homo- logue perhaps in the similar deposit which the ova of several Mammalia acquire in their descent through the Fallopian tube. The chorion of the ovum of Mammalia, being an after growth, has probably no true homologue in the bird's egg, unless we should regard the shell membrane and shell as occupying this place. Many ovologists have thought it of import- ance to establish a comparison between the ovum or its parts, and some one or other of those microscopic structures which, since the publication of the discoveries of Schleiden and Schwann, have been known as organised cells. Schwann himself, though looking upon the entire animal ovum as a cell, entertained some doubts as to the exact nature of the comparison to be instituted for its several parts. These doubts are not yet removed, and the progress of knowledge has tended rather to diminish than to increase the ap- propriateness of the comparison, more espe- cially from the somewhat various and indefinite nature of the bodies which are now recognised as organised cells. It cannot be denied that, if we regard merely the structure of the simpler ova of small animals, we find in them the general characteristics of an organised cell, as these have been usually understood; that is, we find the external structureless vesicular cell- wall, the internal granular contents, and the internal nucleus or inner cell with its nu- cleolus. But when we consider more fully the whole history even of the most simple ova, and extend our regard to the structure and history of the more complex forms of ova, we perceive many circumstances which render the comparison with detached animal cells inapplicable. Leuckart remarks, in his article Zeugung, previously referred to (p. 815.), that if we attempt to deduce the most general result from what has been ascertained as to the formation of the ovum, it is this, that " the animal ovum is formed by deposit round the germinal vesicle." The progressive forma- tion of the parts of the ovum, therefore, would appear to differ widely from that which Schwann held to occur in most cells. But our whole knowledge of the various forms and modes of production of cell-like struc- tures has been extended, and has undergone some modification since the time of Schwann ; and there are now known to be not a few cell structures which are formed by external de- posit of matter round a nucleus, nearly in the same manner as occurs in the ovum. In this view, therefore, the simpler kinds of ova might be regarded as examples of " deposit cells." The great variation in the magnitude of different ova, and the prodigious size which some of them attain, as compared with the minute and generally microscopic size of the organised cells of the animal body, cannot by itself be received as a conclusive argument against the cellular constitution of the ovum ; but the complexity of its structure, its rela- tion to fecundation, the peculiar micropyle of the outer wall in some, the separation of the germinal from the nutritive part of the yolk- substance, and the new formation of cells after segmentation in a limited or more ex- tended space over the yolk in the interior of the vitelline membrane, are so widely different from any thing belonging to the history of other cells in the animal body, that we are forced to regard the ovum rather as a struc- ture of a peculiar kind than as a mere modi- fication of a cell. The germinal vesicle it might be held, both in its structure and its mode of origin, merits, more justly than the whole ovum, the com- parison with an organised cell. But even in its history there are points of difference, and we are still too little acquainted with the mode and consequences of its disappearance at the time of the maturation of the ovum, to warrant our making more than a vague and general comparison of the germinal vesicle to an organised cell. In admitting that the ovum, or its germinal vesicle, present some of the features of the organic cellular structure, we ought always to bear in mind that they are the source of all the other cells from which the animal body is developed. The manner of the very first origin of the germ of the ovum is still involved in obscurity, for we only know of the existence of an ovi- germ when the germinal vesicle has attained an appreciable size. Whence the first germs of the germinal vesicles proceed can as yet be matter only of conjecture. Without enter- ing here upon the debated ground of the origin of organised cells in general *, I would venture to express the opinion, that as there is no ovigerm without a parent, so there is no new organisation without previously existing, and at some time or other connected, orga- nisation. Hence, notwithstanding the appa- * See upon this subject the very interesting and suggestive Review by Mr. Huxley in the Brit, and For. Med. Chir. Review for October, 1853. [**] [136] OVUM. rent isolation of the origin of cells in blastema or intercellular substance, it might still be held that the unseen germs of new cells con- tained in that blastema may have derived their origin from other cells or organised parts proceeding from cells. And thus, in regard to the first origin of the ova of animals, it is fair to conjecture that the germs from which they spring have taken their descent from parent cells or structures derived from cells through the organs appropriate to their form- ation. But here observation fails to assist us further, and we are lost in the region of speculation. If, however, with the reservations now stated, it should be thought desirable to compare the ovum to the organic cellular structures, the germinal vesicle may be re- garded as the simple cell of the ovum, the whole ovum as a complex cell ; the first of these being formed probably by expansion from a minute point or molecule, the second by superposition or external deposit round the internal cell ; but both at the same time presenting features which are peculiar to themselves, and different from those which characterise other cells of the animal eco- nomy. The different and separate formation of the germinal vesicle and yolk, which is perceptible to some extent in the ova of most animals, is placed in its most striking point of view by those instances in which, as in Tre- matode and Cestoid Entozoa, there are dis- tinct germigenous and vitelligenous organs, and those in which, as in Nematoidea and Insecta, the ovary is tubular, and the forma- tion of the several parts of the ovum goes on progressively in different parts of the tube. 4. Phenomena attendant on the maturation of the ovum, and its discharge from the ovary. The ovum naturally undergoes in the ovary a progressive development till it arrives at the state of maturity, when it is usually separated from the ovary by a process of dehiscence, is conducted through the female passages either to be excluded or laid, as in oviparous ani- mals, or to be retained in a uterus or other part of the female organs in viviparous ani- mals during uterogestation. The maturation of the ova and their separation from the ovary is in many animals periodical and inde- pendent of fecundation. This natural peri- odical separation of the ova has been termed Ovulation by some authors.* The change which the germinal vesicle undergoes at the period of the maturation of * The observations of Bischoff had long ago shown that in the periodical dehiscence of ova which accompanies the heat of female quadrupeds, the ova may be detected, though unfecundated, in the course of their descent through the Fallopian tubes and uterus (Periodische Losreifung, &c., 1842), and some observations appear also to have shown that the same is the case in the human female at the periodical return of menstruation. (See a paper by H. Letheby, M. B. in the Philos. Trans, for 1851, p. 57., where two cases are described in which ovules or their remains were detected in the Fallopian tubes of unimpregnated women who had died at or about the menstrual period.) the ovum has naturally attracted much at- tention, from the hope that through the ob- servation of this phenomenon some explanation might be obtained of the first origin of the germ round which, after fecundation has taken place, the segmenting and organising stratum is collected, from which the blastoderm is produced ; but it must be allowed that as yet little success has attended our efforts to de- tect the connection, if it exists, between these two processes. In almost all animals the germinal vesicle is lost to view at the time of the maturation of the ovum, and generally before or about the time when the ovum leaves the ovary. In large-yolked ova the macuke of the germinal vesicle become very numerous by their multiplication and sub-divi- sion at an early period ; while in the small- yolked ova, as has been observed in a few animals at least, the increase in the number of the maculae does not take place till imme- diately before the diffluence or disappearance of the vesicle. The more minute phenomena of this diffluence are as yet very imperfectly known. In some animals, as Mammalia and Birds, it has been observed that shortly before the diffluence of the vesicle, its delicate wall undergoes a softening or approaching solution, so as to make it impossible to separate the vesicle entire. After this, when the diffluence is complete, the contents dis- appear from the situation they have previously occupied, but what becomes of them has not yet been determined. In some instances, as Birds and Batrachia, it has been observed that, after the diffluence of the germinal ve- sicle, the germinal part of the yolk, which previously consisted exclusively of small opaque granules, is now mingled throughout with clear hyaline spherules, somewhat similar to the dispersed maculae of the germinal vesicle ; but it is only matter of conjecture that these clear spherules have been derived from the germinal vesicle or its maculae. In a few instances, as in Ascaris, it has been thought that the entire nucleus or macula of the germinal vesicle has remained undivided, and it has been supposed that it has of itself constituted the germ of the embryo-cell, which afterwards occupies the centre of the first segmenting mass of the yolk, and whose progeny by division exists as nuclei in the interior of the successively in- creasing segments of the cleaving germinal portion of the yolk. A recent observation by J. Muller seems to lead the way to a different view of this phenomenon. He has observed * in one of the Mollusca, the Ento- choncha mirabilis, that the germinal vesicle does not disappear or undergo a change at the time of the maturation of the ovum, but remains discernible as the foundation of the clear embryonic -cell which occupies the centre of the yolk mass when segmentation is about to take place. Rernak f has been led, by his observations on the Batrachian ovum, to * Archiv. der Physiol. 1852. Leydig in the same. + Untersuch. iiber die Eutwickel. der Wir- berthiere. OVUM. [137] doubt the correctness of the view hitherto generally adopted as to the entire disappear- ance of the germinal vesicle in that instance, and holds it as probable that a part of it at least remains in connection with the forma- tion of the embryonic cell. These statements are sufficient to show that the phenomena of the dehiscence of the germinal vesicle and its relation to the subsequent changes in the ovum induced by fecundation are as yet very imperfectly understood, and that the discovery has still to be made of the link in the chain of connection between the last stage of existence of the ovigerm, and the first origin of the nucleus round which the subsequent organising process of segmentation begins. But that some such connection exists, all who have made a study of this part of the his- tory of the ovum are inclined to believe, 5. Relation of the ovum to fecundation by the male sperm. The act of fecundation is necessary for the perfection of all true ova. In the production of gemma? or buds, in the multiplication of nonsexual individuals, and in the various examples of Metagenesis previously referred to, the germs from which the new products arise may be nucleated cells or groups of these, and may without doubt be the descend- ants of the original cell-germs of ova; but for their development into the new beings produced from them, no combination, so* far as is yet known, with the product of cells of a different kind, as in fecundation, is necessary. It is otherwise with all true ova. Their germs may be the descendants through the ovary of an original cell-germ, from which the animal bearing the ovary was produced ; but for the generation of an ovum the ovigerm must be subjected to the influence of the sperm, and for its development there is re- quired a new process of organisation, inaugu- rated by segmentation, which is the invariable consequence of fecundation, and is the first obvious change in a fecundated ovum leading to embryonic formation. The developed form of the spermatic sub- stance * is in by far the greater number of ani- mals that of minute ovoid or rounded particles of various form, with each of which is connected a long and extremely delicate filament, which moves with vivacity in a vibrating or oscil- latory manner when immersed in water and various bland animal solutions. There are other less common forms of spermatozoa, such as those of Crustacea and Nematoidea, which have not the filamentous appendage, and are motionless. The vibratory motion of filamentous spermatozoa bears some resem- blance to that of some kinds of fine cilia, and is the most apparent indication of the active state of their vitality.f It is now ascertained beyond doubt that in a number of animals the spermatozoa come into direct contact with the yolk substance * See the article SEMES. t See especially the recent researches of Kolliker on the Sperm in Zeitsch. fur, Wissensch. Zool. v ol. vii. and embryogerm, or with the internal con- tents of the ovum. The actual entrance of the spermatozoa into the ovum has been observed in Mammalia, Batrachia, Osseous Fishes, Insects, Nematoid Worms, some Mollusca, and Echinodermata ; and there have been ascertained circumstances regarding the ova of other animals which warrant the inference that the spermatozoa enter the ovum in many more than those in which the phenomenon has already been actually ob- served. After long continued doubt and much discussion of this point, physiologists are therefore now generally agreed that in all instances a direct action of the sperma- tozoa in substance on the contents of the egg is necessary to fecundation. The manner of access of the spermatozoa to the interior of the ovum is probably various in different animals. In a few, as Trematode and Cestoid Entozoa, the sperm is mixed with the contents of the ovum, viz., the germinal vesicle and yolk, at the time when these are brought together from the separate organs in which they are formed : in some, as the Nematoid Worms, and probably also in some other animals, the sperm comes in contact with the ovum previous to the formation of an en- veloping membrane ; in a third set it seems probable that, as in Lumbricus, and perhaps in some Mollusca and Hirudinea, the vitelline membrane which had existed at an earlier period is dissolved or removed previous to fecundation, and the ovum or yolk substance and germ are thus left directly exposed to the action of the spermatozoa, which in Lum- bricus have been observed in great numbers penetrating the substance of the yolk. In the majority of animals, however, the sperm only reaches the ovum at a later stage of its formation, when it is already covered by the vitelline membrane or other envelopes, and through these coverings, therefore, the spermatozoa must pass to gain access to the yolk and germ. In a certain number of ani- mals the vitelline or enveloping membrane appears to be quite entire and closed on all sides, so that, as in Mammalia, in which Martin Barry was the first in 1843 to perceive with certainty the entrance of the spermatozoa into the ovum, these bodies must in some way, not yet fully known, pass through the consistent wall of the enclosing membrane ; but in other animals, as first discovered by J. Mtiller, a special aperture or perforation of the egg- covering exists, apparently destined to allow of the more rapid entrance of the spermatic bodies. This micropyk apparatus, sometimes consisting of one, and at others of a number of apertures, has now been observed in several Echinodermata, in Acephalous Mollusca, in all Insects, and in Osseous Fishes ; and it is more than probable that it exists in a considerable number of other animals in which it has not yet been detected. But still, making due allowance for the probable extension of discovery in this direction, the care and accuracy with which the micropyle apparatus has since its first discovery been sought for without success in Mammalia and [138] OVUM. some other animals, in which, had it been present, it could scarcely have escaped so careful a scrutinj', warrant the belief that in a certain number of animals the spermatozoa do actually penetrate the apparently entire egg- covering. It is not my design to enter here upon the consideration of the mode and nature of the action exerted by the spermatic matter or the spermatozoa in producing the changes of fecundation. Upon this subject the reader may with great advantage and interest consult the latter part of the article Semen in this Cyclopaedia by R. Wagner and Leuckart, the papers of the late Mr. Newport in several recent volumes of the Philosophical Trans- actions, and the learned article by Professor Leuckart on Generation contained in the fourth volume of R. Wagner's Handbuch der Physiologic. I will only remark in passing that from Mr. Newport's and other researches it appears that while the actual mixture of an appreciable quantity of the spermatic sub- stance is necessary to induce fecundation, the extreme rapidity with which the action takes place, the minuteness of the quantity of the spermatic matter which is sufficient to induce it, and the fact now observed in a variety of instances that the spermatozoa which have entered the ovum remain apparently little changed for a considerable time after the changes of the ovum consequent on fecunda- tion have made some progress, — lead to the conclusion that there is something in the nature of this action inconsistent with the idea that it is one of mere combination in substance of the developed contents of the male and female generative products. But whether this is to be referred to the class of " contact actions " of which themselves so little is known, or to what other kind of action it may be compared, the ascertained facts do not enable us in the least to deter- mine. The almost universal presence of vi- bratory motion in the spermatozoa during the time in which they retain their fecundating power, naturally led physiologists to connect that motion with the fecundating action ; but on the other hand, the occasional, though rare examples in which the spermatozoa are en- tirely motionless, seem sufficient to cause the rejection of the view that the force which produces the vibratory motion is identical with that which calls forth the series of histogenetic and organogenetic changes which result from fecundation. ' But the consideration of this subject would lead us into the discussion of the whole question of vital forces, which in its present unsatisfactory state it is desirable to avoid. The physiologist agrees, for the sake of con- venience of expression, to adopt the terms of power, property, force, &c., to denote the con- ditions necessary for the occurrence of certain actions or changes. He employs the term vital force merely as the indication of the supposed cause or causes of an ascertained regular sequence of vital phenomena ; but all philosophical accuracy rejects the idea of any unseen separate and single force which is at work in bringing about the sequence in ques- tion. The fecundating power of the semen is an expression used only for convenience to denote the invariable sequence or relation as cause and effect which has been observed to subsist between the contact of spermatic matter with the ovum, and the changes in the latter which follow on the act of fecundation. We might with as much propriety have given a name to a separate power residing in the egg or its germ which render it susceptible of fecundation, as of a special power belonging to the semen by which that susceptibility of the ovum is acted upon. The efficient cause of the process of fecundation can only be educed, as in all physical as well as vital changes, from a perfect knowledge of all its phenomena, and the statement of the efficient cause of such actions is only the expression of the most general and best known law to which a full acquaintance with the phenomena enables them to be reduced. Fecundation is to be regarded as a purely vital change, seeing that it takes place only in the usual conditions of vitality ; but, like all other vital changes, it appears more probable that a variety of conditions of the organic matter rather than any one known property or condition are necessary for its occurrence. In endeavouring to deduce the most ge- neral phenomena which accompany this re- markable change, it may be said that fe- cundation consists essentially in the mutual action of two different organised bodies, which are respectively formed from two different cells ; the ovigerm and the sperm- germ. If we may form any general con- elusion from what may be so well observed in Nematoid Worms, the development of the ovum and the spermatic cells from their re- spective germs is remarkably similar, for in both the internal cell is developed from a minute molecule from within, while the ex- ternal part is deposited from without. The spermatozoa are formed in connection with the nucleus or nuclei of the sperm-cell ; and the germinal part of the ovum, though it con- sists mainly of the granular part of the yolk, which is directly formative, very probably comprehends also in some shape or other the effused contents of the germinal vesicle. In this way, then, we may conjecture that in the act of fecundation the products of the original cell-germs meet and combine or mutually influence each other. The cell-germs, then, are the links in the chain of organic connec- tion between either or both the parents and the progeny capable of being developed from the fecundated ovum. Such a view, though still in a great measure speculative, seems to be in accordance with the facts known as to the perfect transmission of the structure and qualities of either or of both parents to the offspring.' 6. Immediate effects of fecundation on the ovum ; segmentation, and first changes of the ovum related to the commencement of em- bryonic development. It does riot come within the scope of the present article to describe in detail the pro- cess of fecundation, or the phenomena which follow it, but it may be proper to state here in a general way the relation which subsists between the earliest changes occurring after fecundation, and the commencement of those phenomena of a histogenetic nature which precede the formation of the embryo itself. The most obvious and constant of these changes is that known as the cleavage of segmentation of the yolk, —a process which has been observed in the ova of all animals, and is not less interesting from its own na- ture, than from the bearing of its phenomena upon the explanation of the earliest organising process of embryonic development, and upon the whole subject of histogenesis. The segmentation affects only that part of the ovum of animals which is directly ger- minal or formative ; and it results in the pro* duction of that layer of organised cells, of variable extent, in the centre of which, in a determinate position and direction, the rudi- ments of the embryo are first formed. The process of segmentation is, therefore, the pre- lude to the formation of the Blastoderma or germinal membrane of Pander. The extent, therefore, to which segmenta- tion affects the yolk differs greatly according to the amount of the yolk-substance which is directly germinal ; that being in some animals the whole, and in others only a fraction of the yolk, in proportion to the part which is only indirectly nutritive. In that group of ova, then, to which those of Mammalia belong, and which we have called the small-yolked, the entire yolk, or, at all events, its superficial layer, being directly formative, or being in- volved from the first in the production of the Blastoderm, the segmentation is complete, or the process of cleavage affects the whole mass of the finely granular yolk within the 2ona or vitelline membrane. In those ova again, such as we find in the bird among vertebrate, and the cuttlefish among the invertebrate animals, in which the formative yolk has the most limited extent, and consists only of a finely granular disc near the surface of the much larger mass of the cellular nutritive yolk, the segmentation is confined to that disc alone, and is therefore, in some respects, widely different from that which occurs in Mam- malia. In the intermediate group of ova be- longing to Batrachia and Osseous Fishes, there are many gradations of transition from the complete to the partial cleavage, so that in some, as the common frog, it is nearly, but not entirely, over the whole yolk ; while in others, as in the salmon or osseous fishes, it does not extend over more than a third of the surface of the yolk.* * The more important phenomena of the yolk- germ cleavage or segmentation have been ascer- tained principally by the following observations: viz. 1st. of Prevost and Dumas in Batrachia, as early as the year 1824, and subsequently of Rusconi and Von Baer in the same animal ; 2nd. of Bischoff and Barrj- in Mammalia, in 1838-39, their obser- vations being confirmed by myself in 1810, and greatly extended by Bischoff before the publication of his work upon the development of the rabbit, in 1842 j 3rd. of Bagge in 1841, and of Kolliker in OVUM. [139] In the greater number of instances there is recognised in the mass of the whole yolk, or in its germinal part, immediately previous to its undergoing segmentation, a clear simple cell, generally nucleated, which was not be- fore perceptible ; to this the name of embryo- cell has been given, in order to distinguish it from the germinal vesicle, from which it has hitherto been believed it is in some measure distinct. In other instances a clear spherule or space only is observed in the place of the embryo -cell, and in a few animals no clear part of this nature has yet been detected. The division of the embryo-cell accompanies, or rather immediately precedes, that of the germ-yolk, so that each mass formed by the cleavage, grooving, or segmentation, as the case may be, contains as its nucleus or centre an embryo-cell, or clear spherule of its own, descended from the first cell or spherule of the same description. The process of segmentation, whether it involves the whole ovum, or is limited to a larger or smaller disc of the yolk, proceeds in most animals with a certain degree of geo- metric regularity, so that the number of germ- yolk segments are successively multiplied so as to be in the numbers 2, 4, 8, 16, 32, 64, &c., until by the ultimate division a vast number of small globular masses are formed, which occupy principally the surface of the yolk over all its germinal portion.* The last result of the segmentation is the production of the blastoderma or germinal membrane in which, by other changes, the rudiments of the embryo subsequently make 1843, on Xematoid Worms ; 4th. of C. Vogt in the Salmonidae and in the Alytes Obstetricans in 1842 ; 5th. of the same author, of Quatrefages, and many others in various invertebrate animals ; 6th. in its most limited form the phenomenon was first well described by Kolliker in Cephalopoda in 1844 ; and 7th. in birds by Bergmann in 1846, by Coste in 1848, and by myself in the following years. The observations on this subject are far too numerous for quotation; those especially which have been made in experiments by artificial fecundation are most favourable to the investigation of the seg- mentation and other phenomena which follow immediately on fecundation. And in all these instances, as well as in very numerous others, the occurrence of segmentation and the regularity of its phenomena are so constant that we may regard it as one of the best established series of facts in organic nature. The observations with regard to segmentation in the ova of insects, which are still imperfect, form the only exception to the foregoing statement with which I am acquainted. * Reference is here made chiefly to the best- known and most common kind of segmentation, in which this process consists in the massing of the granular and fluid substance of the yolk round the embryo-cells or clear spheres as centres ; but it is right to state that there is another form of this process, as yet only observed in some of the Cestoid and Nematoid Entozoa, in which the yolk, either clear or granular in its structure, does not appear to follow the divisions of the embryo-cells, but the gradually increasing progeny of the latter assi- milate or combine more and more with the yolk, so that at last, when the germinal part of the ovum is entirely occupied with new cells, the original yolk has quite disappeared. The nature of this process, as compared with the more common form of yolk segmentation, is not perhaps as yet fully understood. [HO] OVUM. their appearance. According to most ovo- logists, the last globules formed by segmenta- tion are the nucleated organised cells im- mediately constituting the blastoderma. A different view of the process, however, in Mammalia, has been taken by Bischoff, very decidedly set forth in his two most recent works on the development of the guinea-pig and the deer; according to which the last resulting spherules formed by segmentation are not true cells, and that previous to the formation of the blastodermic cells, the yolk- germ falls completely into an amorphous or homogeneous finely granular substance, out of which, secondarily, the blastodermic cells are produced by a process of cytogenesis. It seems probable that, in the different classes of animals, there may be considerable variety in the degree of perfection in organisation or ad- vance in cell-structure to which the segments of the yolk have attained at the period when the development of the embryo begins to ma- nifest itself. But in the higher animals at least the weight of evidence appears to me in favour of the view that the process of segmentation results directly in the formation of blastodermic cells. The fact now established by the obser- vations of Reichert in Entozoa, in 1841, of Ransom in osseous fishes, and more particu- larly those of Remak in Batrachia, that a de- licate membrane is formed over the surface of each of the segments as they appear, and that the last and smallest segments possess a deli- cate membranous envelope, appear to show that, in these animals, each segment has the structure of an organised cell, and is very si- milar to, if not identical with, those of the blastodermic lamina. The origin of the embryo-cell is still in- volved in obscurity. Most ovologists are dis- posed to connect it in some way or other with the previously existing germinal vesicle, or some part of its contents, and more especially the nucleus. For the solution of this ques- tion, as already remarked, a more accurate knowledge of what happens to the germinal vesicle at the time of that disappearance which has been so commonly observed at the period of the maturation of the ova of almost all ani- mals, will be required. Does the macula re- main, as has been alleged by some, to form the nucleus or the whole of the embryo-cell? Or, in other cases, if the multiplied maculae are dispersed among the granules of the ger- minal yolk, are they again collected together into a mass or spherule to form the embryo- cell? Or, again is the embryo-cell formed out of other materials, and not necessarily either partially connected with, or wholly de- rived from, the germinal vesicle ? And finally, might it not be, according to some recent ob- servations, such as those of J. Miiller on En- tochoncha and those of Remak on the frog, that the disappearance of the germinal vesicle is not attended with the dispersion of its con- tents, but is a phenomenon caused only in a certain number of animals by the solution of the delicate external wall of the vesicle, and by some change in the position and consist- ence of its contents ? Further observations will be required to determine this point ; but if in the meantime we regard it as most pro- bable that the embryo-cell is in some way or other connected in its origin with the germinal vesicle, we might further found upon this the speculative view that the blastodermic cells and the blastema from which unques- tionably, by a histogenetic process of cell-di- vision and multiplication, the various textures and organs of the animal body are produced, may be regarded as the descendants of the original cell-germ from which the ovum was developed combined with the sperm. We should thus trace the organic cellular connec- tion between the succession of parents and offspring, which I have stated to be one of the most general facts in organised nature. The observations respecting the very re- markable movements of the yolk, before and during the earlier stages of the segmenting process which have now been recorded by several physiologists, must excite the liveliest interest, and suggest subject for much reflection as to the evidence they may afford of the causes of this change, or, if we may use the expression, of the forces by which segmenta- tion is brought about. There seems to be little doubt that the embryo-cell (and its nu- cleus first of all) is the earliest to become di- vided, and that the process of cleavage then proceeds from the surface of the segmenting mass inwards towards the cell ; but in what relation the nucleus, granular substance of the yolk, and ovicell-membrane stand to each other in this process, must be left to be de- termined by future researches. Of the other early changes in the ovum which immediately follow fecundation and precede embryonic development little need here be said. They consist principally in the greater degree of consolidation and compact- ness acquired by the germinal part of the yolk, and in the formation in most animals of a clear space between the surface of the yolk- substance and the enclosing vitelline mem- brane. It is in this clear space, or, as it has been called by Newport, respiratory chamber, that the spermatozoa have been observed in those instances in which they have been as- certained to penetrate into the cavity of the ovum. There is another phenomenon of the same period, which has now been so frequently observed, and which is of so peculiar a nature, that it must not be passed over without no- tice ; I allude to the appearance in the re- spiratory space of one or more clear and highly refracting spherules, nearly of the size of the germinal vesicle, but quite independent of it. These clear hyaline-like globules have been observed in the ova of Gasteropodous Mol- lusca after fecundation by almost all those who have attended to the ovology of this class of animals, among whom may be mentioned Dumortier, Pouchet, Van Beneden, Nord- mann, and Vogt; in the Annelida by Quatre- fages ; in Mammalia by Bischoff' and Barry ; and in Batrachia by Newport. From the observations of Quatrefages in Hermella they appear to be excluded or expressed, as it were, from the clear basement-substance of OVUM. the yolk ; and Bischoff states that they gra- dually disappear, or are dissolved without obvious change. We are at a loss to deter- mine what office these globules may have in connection with the changes of the ovum at the time they appear. Lastly, I would notice the interesting re- lation which appears to subsist between the situation of the germinal vesicle and the cen- tre of the germinal membrane afterwards formed, or the germinal pole of the ovum, and the conformity in the direction of the line of the first cleavage of the yolk with that of the principal axis of the embryo in verte- brate animals. The first fact has been observed in all animals, and the latter has been ascer- tained by Mr. Newport's researches in Ba- trachia, and by observations which I have myself made in the bird's egg during its de- scent through the oviduct. These facts, as yet inscrutable in their nature, point to in- teresting laws relating to the connection of the first phenomena of development, which may be worked out by the further prosecution of these inquiries. In the preceding part of this article we have considered chiefly the anatomical struc- ture of the ova of animals, and have made little mention of their chemical composition. The knowledge of the latter subject is as yet very imperfect. In a recent Memoir* Messrs. Valenciennes and Fremy have given an ac- count of an extended series of experimental researches in which they have been engaged, with a view to determine the differences in the chemical composition of the ova of dif- ferent animals, and although this investigation is still necessarily incomplete and fragmentary, they appear already to have arrived at some interesting results. The following are some of the more important of these results. The albumen or white is not exactly of the same composition in the eggs of different birds ; but it generally contains albumen with salts and a compound of sulphur in solution. In the yolk of birds' eggs they recognise the principle first distinguished by Dumas and Cahours as Vitellmey a substance precipitable by mixture with a large quantity of water, and apparently more nearly resembling fibrine than albumen in its composition and some of its properties. The phosphuretted fat of the yolk is somewhat similar to the cerebral fatty matter. The glairy white of the eggs of cartilagi- nous fishes is very different from that of birds' eggs, being neither soluble in water nor coa- gulable by heat nor acids to the same degree. It seems to contain only traces of organic matter. The angular and tabular particles of the yolk of cartilaginous fishes are com- posed of a principle which these authors re- gard as peculiar, and have named IcJithine. This substance is insoluble in water, alcohol, and ether, and, on being dissolved by hydro- chloric acid, gives no violet colour, as albu- men does. It is dissolved by all the concen- * See Journal de Pharmacie, &c., vol. xxv. pp. 321. and 415., and vol. xxvi. p. 5., 1854. trated acids, and by dilute acetic and phos- phoric acids. Its composition is stated to be as follows: carb. 51 ; hyd.a6*7; nit. 15; ox. 25*4 ; phosph. 1*9. In the ova of osseous fishes these authors do not find the same organic principle, but have detected two others in variable propor- tions. One of these, which they have named Ichtkidine, exists only in small "quantity, and is absent in some fishes : it is quite soluble in water. The other which is more generally prevalent and in larger though variable quan- tity is precipitated by water into a viscous substance. This has been named Ichthuline. Messrs. Valenciennes and Fremy have ascer- tained the interesting fact that while these principles, especially ichthuline, exist in large quantity in the ova at an early stage of their growth in the ovary, they gradually diminish in quantity or are changed as the ova ap- proach maturity, and give place chiefly to albumen, which holds the phosphuretted fat in suspension. In the salmon's egg there is a large proportion of ichthuline, which is the cause of their becoming opaque when water enters the yolk. These authors propose in- deed this character as a test of the maturity of the ova, as they are not rendered opaque by water when mature. It would be inte- resting to know whether fecundation produces any immediate chemical change on the prin- ciples of the yolk. The composition of ich- thuline is stated to be as follows : carb. 52'5 ; hyd. 8 ; nit. 15'2; ox. 22'7 ; phosph. 0'6 ; sulph. 1. The ova of Batrachia seem to resemble most nearly those of cartilaginous fishes, in so far that the tabular particles of the yolk are composed of ichthine. The external ge- latinous covering is described as a tissue of hyaloid membrane which absorbs water in a determinate quantity. The ova of Ophidia and Sauria resemble nearly those of birds in the composition of the white and yolk, containing the principle vitelline in the latter. The yolk of the Viper presents the singular peculiarity of becoming gelatinous by immersion in water. In the ova of several Chelonia they have detected a different principle from vitelline to which they give the name of vitelline. This principle is soluble in potash, and has the following composition : carb. 49'4< ; hyd. 7'4 ; nit. 15'6 ; ox. and phosph. 26'7. Among the invertebrate animals Messrs. Valenciennes and Fremy have examined the ova in several classes. In the Crustacea they have given much attention to the in- vestigation of the curious colouring principle of the ova, which appears to be the same as that existing in the shell, and which being green in the moist state passes into red in a variety of circumstances. They have isolated this colouring matter by a very simple pro- cess, and give an interesting account of its properties, especially of the circumstances causing it to change to red, such as the ac- tion of alcohol, boiling, desiccation, placing in a vacuum, friction, &c. The ova of Arachnida am! Insects are [142] OVUM. quite different from those of Crustacea in their composition, containing albumen, fatty matters, and a large quantity of a substance precipitable by water. The ova of Mollusca differ greatly in com- position from those of other animals : more particularly in the entire absence of fat from them. From these researches it appears that there are considerable differences in the chemical composition of the ova of animals of different great groups, and even among those not far removed from each other in the zoological scale, and that there are also considerable differences according to the state of advance- ment of the ova of the same animal, more especially it would appear that a marked change of composition takes place at the period of complete maturity. The researches referred to appear to have brought to light several new organic principles which are modifications of albumen or belong to the same class, and which may be considered as Vitelline principles as belonging to the yolk of different animals : such are Vitelline, Ich- thine, Ichthidine, Ichthuline, and Emydine. The full citations of different works and memoirs on the subjects of this article render it unnecessary to give any detailed bibliogra- phical list at its termination. I may, how- ever, call the attention of the reader to the following works already cited, as forming the principal basis of modern knowledge of ovo- logy and development, viz.: The Inaugural Dissertation of Pander on the Development of the Chick, published in 1817. The His- tory of the Egg before Impregnation, by Purkinje, in 1825. The Epistola of Von Baer, in 1827. The contributions of Von Baer and Rathke to Burdock's Physiology, in 1827 and 1828. The various Memoirs by Rathke at different times, and Von fitter's Lectures on Development, completed in 1837. The Systematic Manual of Develop- ment by G. Valentin, in 1835. The Prodro- mus and contributions by R. Wagner, in 1836. and the Manual of Physiology by the same author. J. Mullens Physiology, and especially the English translation of the more recent edition. The researches of Martin Barry, in 1838 and 1839. The various contributions of JBischof, beginning in 1838: His Systematic Treatise on Development in 1842, and his Monographs on the Development of the Rabbit in 1842, of the Dog in 1845, of the Guinea Pig in 1852, and of the Deer in 1855. The researches of Coste beginning in 1833; his work on Comparative Embryology in 1837, and his large and beautifully illustrated work, as yet unfinished, beginning in 1850. The works of C. Vogt on the Alytes Obste- tricans (Batrachia) and on the Embryology of the Salmonidae, in 1842. Lastly, the re- cent and valuable researches of Remak on the Development of Vertebrata in 1853-1855; and the republication of R. Wagner's Icones Physiologicae by Ecker. The works relating to the invertebrate animals are much too numerous for quotation. I will only mention the researches of Kolliker on the Cepha- lopoda, of Qiialrefages, Vogty and others on the Mollusca, Annelida, &c., and those of J. Miiller on the Echinodermata. I would also refer the reader to the excel- lent report on the progress of discovery in regard to the Ovum by Thomas W. Jones in the Brit, and For. Medical Review for Oct. 1843, to Bischoff's article on the History of Discovery in Development, and its application to the explanation of Malformations in Wag- ner's Dictionary of Physiology, to Leuck- art's Article on Generation in the same work, and to Vrolik's Memoir on the Explanation of Monstrosity from the History of Deve- lopment, and to his article Teratology in this Cyclopaedia. A large amount of information on the whole of our subject will also be found in C. Vogt's interesting Letters on Living and Fossil Animals in 1851 ; in Victor Carus's System of Animal Morphology in 1853 ,- in Van der Hceven's Manual of Zoo- logy, with additions by Leuckart in 1850- 1856 ; and in the English works of Carpenter, Oiven, and Rymer Jones on Comparative Anatomy and Physiology. In now bringing this article to a close, the author owes an apology to the conductors and the readers of this Cyclopaedia for the extreme tardiness with which it has appeared. The delay has arisen, in part, from personal circumstances which need not be mentioned here, and in part from the nature of the sub- ject of which the article treats. In the ori- ginal plan of the article, it was intended that it should comprehend, along with the history of the ovum, an account of the development of the embryo. But as time advanced, and every successive year added new and im- portant matter to our knowledge of the science, and greatly modified the statement of facts previously regarded as established, it became more and more difficult, especially in the hands of one interested in the experimental investigation of many of the individual facts, to present a systematic and at the same time clear and brief description of the researches of physiologists on the subject of develop- ment. The author regrets deeply that he should thus be prevented from furnishing the readers of the Cyclopaedia with this part of the article as originally intended. But at the same time he believes that when the recent rapid progress of many departments of the subject is considered, and the vast number of details which would be required to embrace even the shortest account of the origin and formation of all the textures and organs of the animal body, the knowledge of which forms a science that is coextensive with the whole range of anatomy and physiology, it may be thought that he has in present cir- cumstances judged rightly in abandoning the attempt to compress into a limited space the statement of so extensive and important a branch of physiological inquiry. (Allen Thomson, M. D.) PANCREAS. 81 PANCREAS (TUy/cpeas*, Gr.; Pancreas, Lat. ; le Pancreas, Fr. ; die Bauchspeicheldruse, Germ. ; Pancrea, Ital.). The pancreas is an azygous, non-symmetrical, glandular organ, possessing a duct, and, therefore, belonging to the category of true glands; connected anatomically with the alimentary canal, and physiologically with the function of digestion. On taking 'even the most superficial and general view of this organ, two or three things cannot fail to strike the attention : one is, the close affinity and strong contrariety which it at the same time displays to the salivary glands f — affinity in point of appearance and structure, being, like them, a typical represen- tation of a conglomerate gland, — contrariety in point of situation and function, the one being placed at the very threshold of the ali- mentary canal, the other at an advanced po- sition in it ; the one acting on raw material, and having in part at least a mechanical use J, the other having to do with material far gone in the process of assimilation, and possessing a function, whatever it may be, certainly not mechanical in any degree. Another striking circumstance is its wide diffusion. It exists in all vertebrata ; — mam- malia, birds, reptiles, and most fishes, all possess a pancreas, and that quite independent of what the nature of their food may be, animal, vegetable, or mixed ; a fact that one would have imagined would itself have pre- vented the adoption of the old views with regard to its function. Another circumstance, not less striking, is its constant relation to the duodenum : \\hatever may be the other modifications of the alimentary canal, from the straight and simple tube of some carnivora to the volu- minous apparatus of the vegetable feeders, or whatever may be the modified form of the pancreas itself, still, if the organ exists, its relation to the duodenum is invariable ; if there is a duodenal fold, it is placed in it ; and if there is not, it makes the closest approxi- mation to an analogous position that is pos- sible : indeed the uniformity of this relation is so invariable, even under circumstances where it would appear to be indifferent, that one cannot but regard it as one of those in- stances of conformity to type in which uni- formity appears to exist for uniformity's sake. The arrangement of the subject of this paper that most naturally suggests itself, is to treat first of the structure, and then of the functions of the organ. I shall therefore arrange my observations under the following .heads : — 1st. The descriptive anatomy of the human pancreas, including an account of so much of its structure as may be made out by a naked- eye examination. 2nd. Its minute or general anatomy. * Trav xpeaj1, all flesh. t This striking resemblance suggested to the older anatomists the name of "salivary gland of the abdomen," an appellation first given to it by Siebold. — Historia Systematis Salivalis. I See Bernard's experiments on the secretion of saliva. Supp, 3rd. Its comparative anatomy, including those modifications both of the form and ulti- mate structure of the gland that the animal series exhibits. 4th. The physiology of the pancreas, — the role that it plays in the function of digestion. Lastly. A short account of some of the most striking pathological changes that the organ is liable to. I. HUMAN ANATOMY. Situation. — The pancreas is so placed that for its display it is necessary to open the ca- vity of the great omentum. This may be done either by dividing the gastro-hepatic omentum and depressing the stomach, or by detaching the gastric layer of the epiploon and turning the stomach up, or by dividing the transverse mesocolon and turning up both transverse colon and stomach. In either of these ways the cavity of the omentum is opened, and the organs concealing the pancreas are removed. Placed transversely across the upper part of the abdominal cavity, and closely applied to its posterior wall, the pancreas extends from the duodenal fold on the right to the hi! urn of the spleen on the left, across, therefore, the epigastric into both hypochondriac regions. It is not perfectly transverse, however, but ex- tends from the right a little upwards as well as to the left ; it corresponds to the level of the first and second lumbar vertebrae and to the splitting of the two laminae of the trans- verse mesocolon : it is post-peritoneal, being invested by that membrane only on its an- terior surface. Relations. — By its right extremity it is closely engaged in the curvature of the duo- denum, to the inner border of which it is intimately attached, and which it often re- ceives into a groove more or less deep, formed by a projection of the gland to a slight extent on the anterior and posterior surface of the intestine. Sometimes this groove is very slight, and the relation of the margins of the gland and intestine merely that of apposU tion ; at others, the inner margin of the duo- denal fold will be deeply imbedded in the gland substance, the projection both in front and behind being considerable. More fre- quently, however, the gland trespasses much further behind the intestine than it does in front, so much so occasionally as to separate it in a great degree from its posterior rela- tions. The structures on which the posterior surface of the pancreas rests are, the vena cava, the bodies of the vertebrae, the aorta, the crura of the diaphragm, the left kidney, its supra-renal capsule and renal vessels, the lower part of the solar plexus with the com- mencement of the plexuses thence pro- ceeding, as the aortic and superior mesenteric ; the splenic vein passing from left to right, the superior mesenteric vein and artery, the vena portae, the common bile duct, many lym- phatic vessels and glands, and the commence- ment of the thoracic duct and vena azygos. To all these structures it is intimately at- tached by cellular tissue, and to the irregular surface which they form it is, as it were, moulded or modelled, so that when it is care- 82 PANCREAS. fully dissected away, it presents eminences for instance, the longitudinal furrow occupied and depressions corresponding to them, as, by the splenic vein, and the deep groove in Human Pancreas, shown in situ by throwing up the stomach. This drawing was taken from a young subject in which the curvature of the head of the pancreas, following that of the duodenum, was par- ticularly well shown. •which the superior mesenteric artery and the vena portae are received. In front it is in relation with the posterior surface of the stomach, which rests on it when empty (tanquam pulvinar, Scemm.), and moves freely upon it ; but when this organ is distended with food, it recedes from it, and its lesser curvature comes into more immediate relation with the gland. In cases in which the stomach is situated lower down than usual, as in emaciated individuals, where a great part of the small intestine occupies the cavity of the pelvis, the pancreas comes into relation in front either with the liver, or with the anterior wall of the abdomen, from which the gastro-hepatic omentum alone separates it, and through which it may be easily felt. This disturbance of the normal relations al- ways exists, according to Cruveilhier, when- ever the vertebral column can be felt im- mediately behind the walls of the abdomen. The pancreas is also in relation, in front, with the angle formed by the ascending and trans- its entire length ; it is in relation also with the Spigelian lobe of the liver, with the first portion of the duodenum, and the cceliac axis. The lower border is bounded by the inferior horizontal portion of the duodenum, from which it is separated, near the middle line, by the superior mesenteric vein and artery, which notch it, and which also separate it from its reflected portion or head. The right extremity is engaged in the duo- denal fold in the manner described, and is in relation with the ductus choledochus. From the intimacy of its attachments to the duode- num, it always accompanies this intestine in its displacements, so that when the duodenum is situated lower down than usual, which happens in displacements of the stomach downwards, the head of the pancreas is al- ways removed in the same direction. The left extremity is in relation with the left kidney, and with the spleen upon which it is sometimes flattened and blunted, and sometimes slightly enlarged, and to which it verse colon and with the commencement of is attached bv the intervention of the splenic the duodenum. The upper border is in relation with the splenic artery, for the reception of which it is grooved, and which often runs in a canal formed in the substance of the gland through veins, which send many branches into its sub- stance : sometimes it does not extend quite so far as the spleen by half an inch or an inch. Shape. — From its elongated form, the pan- PANCREAS. 63 creas has been described by anatomists as possessing a body and two extremities ; and of these extremities one, which is enlarged and clubbed, has been called the head; the other, tapering and acuminated, has been called the tail; the middle portion, the great mass of the gland, being the body : other describers* have suppressed the body altogether, and de- scribed as the tail all that portion which is not included in the curved intumescence at the right extremity, which they designate the head. Indeed the imaginations of anatomists have been largely drawn on to supply analogies whereby to illustrate the shape of this organ. Some have compared it to a hammer, — some to a clog's tongue; among them all I think the best is that which compares it to a pistol. But, passing by these fanciful resemblances, the pancreas, from its transverse elongation and antero-posterior flattening, presents for description a right and left extremity, an upper and lower border, and an anterior and posterior surface ; and these parts 1 shall de- scribe in succession in the order in which I have mentioned them. The right extremity, to which the name head has been assigned, is that portion which is engaged in the duodenal curvature, and to which, from its occasional separation from the rest of the gland, the name of lesser pancreas has also been given-f- : it differs from the rest of the gland in being thicker and more mas- sive, curved instead of straight, and situated on a more posterior plane. It is thus formed : — when the pancreas, in passing from left to right, has arrived at the duodenum, it be- comes closely attached to that viscus, and follows its course, first downwards, and then to the left, passing by its extremity, behind the superior mesenteric vessels, for which it thus forms a sort of groove or channel. It is by the fusion and massing of this curvature that the head is formed ; but in very young subjects, and in the lower animals, the curva- ture of the pancreas is as conspicuous as that of the duodenum, and by separating it from its attachments, and straightening it out, all ap- pearance of head vanishes, and it becomes a long prism, or flattened cylinder of even thick- ness throughout. In the human adult, however, it is impos- sible thus to unravel and straighten the right extremity ; and the fusion of the parts has often proceeded to such an extent as entirely to obliterate the original curvature, the groove for the vena portas and superior mesenteric vessels being the only trace of its concavity. The left extremity gradually tapers, getting both narrower and thinner ; it is sometimes bifurcated, sometimes blunted and flattened against the spleen, and sometimes slightly enlarged ; it presents nothing for special de- scription. The upper border is much thicker than the lower, so much so, that some anatomists have described the gland as being prismatic. * Meckel, Manuel d' Anatomic. f Some anatomists, as Professor Ellis, make the head synonymous with the lesser pancreas, inde- pendently of this separation. In the middle the coeliac axis rests upon it ; to the right the hepatic artery and first portion of the duodenum are in contact with it, and to the left it is deeply grooved by the splenic artery. This groove does not run along the top of the border, parallel to it, but crosses it ob- liquely from behind forwards as it passes to the left extremity, curving over it, as it were, so that while the commencement of the ar- tery is behind the pancreas, its terminal branches are in front (see^g. 54.). Some- times this groove is converted into a canal, by the gland closing over it. The loiver border, much thinner, is tilted rather forwards to the right, by the passage of the superior mesenteric vessels beneath it, which separate it from the third portion ot the duodenum ; on the left the inferior me- senteric vein passes beneath it to join the splenic. The anterior surface looks upwards as well as forwards, and is convex both transversely and longitudinally ; it is the only portion of the gland that is covered by peritoneum : from this circumstance, as well as from its being the free surface, it is very smooth. The posterior surface contrasts strongly with the anterior, for being uncovered by peri- toneum, and closely applied to all those struc- tures against which it lies, it presents many irregular elevations and depressions, corre- sponding with the uneven surface which these structures contribute to form. Size and weight. — The size and weight of the pancreas are liable to great variety, and hence different authors have stated them very variously. Wharton * gives its weight as five ounces ; Meckel, from four to six ; Cruveilhier states its limit as six ounces, but thinks that a healthy pancreas may be as small as two ounces and a half; Soemmerring also considers six ounces a maximum, but carries his minimum as low as an ounce and a half. According to Krause and Glendinning, its usual weight is from two and a quarter to three and a half ounces. Its size is stated by Meckel as six inches long and one thick*; Ellis gives its length as seven inches ; Quain and Sharpey, from six to eight inches, with an average breadth of an inch and a half; according to Wharton, its length is about five inches, its greatest breadth one and a half, and its thickness one inch. Of all these weights and measurements I think that of Wharton, which is the earliest, comes nearest the truth ; only his measurement of length is too little. From a large number of obser- vations I find the average weight to be from four to five ounces, the length seven inches, the greatest breadth an inch and a half, and the thickness three quarters of an inch. It is smaller in wome/i than men, but only in proportion to the difference of size. Scemmerring saysf that it is proportionately larger in the foetus and the new-born infant * Adenographia, p. 72. I "In nonduui nato homine et brevi adeo post parttim, majus pro corporis mole videtur quam in adulto.'' Corp. Hum. Fab. o 2 PANCREAS. than in the adult ; a statement that my own frequent observations have verified. The specific gravity of this gland, accord- ing to Muschenbroeck*, is, compared to water, as 2029 to 1000. General appearance. — The best view of the external appearance of the pancreas is obtained on its anterior surface where it can be seen, through the peritoneum covering it, without any disarrangement of its structure. It is seen to be of a pale, clear, flesh colour, in which it strongly contrasts with the white cellular tissue investing it, with the yellow fat with which it is often surrounded, and with the grey and dingy coloured absorbent glands which lie contiguous. On looking more closety, it is seen to be mapped out into lobules, and this mapping out is sometimes more conspi- cuously marked by the septa of areolar tissue that separate the* lobules being loaded with fat. The lobules are of very various shapes and sizes, from an eighth to three quarters of an inch in diameter, closely packed so as to fit into one another, and presenting an even general surface. But on a closer examination we see that these lobules are themselves sub- divided by less conspicuous septa into a great number of smaller lobes ; and these again, especially if assisted by a little separation with a fine knife or needle, are seen to consist of numerous minute granules, or acini, as they are termed, which, as far as the scrutiny of the naked eye goes, appear to constitute the ultimate structure of the gland ; but, as we shall see more fully presently, the microscope shows these in their turn to consist of aggre- gations of follicles, and therefore to be truly compound. Thus a mere inspection of the external surface of the pancreas gives an indication of its internal structure ; we see the acini by their aggregation constituting the lobules, the lobules the lobes, and the lobes the whole organ ; the association by which these parts are bound together being more and more intimate as we descend from the greater to the less ; but all of them, even the smallest, that come under the cognisance of the unassisted vision, being truly composite : this is a common character, and indeed a fmeral description, of all conglomerate glands, he pancreas in consistence is moderately firm, the lobules having a considerable degree of hardness, but the whole gland having a certain laxness about it, from the way in which the lobes are hung together by areolar tissue. There is no proper capsule to the pancreas : the areolar tissue which invests it does so very unequally in different parts, and is strictly continuous on the one hand with that which attaches it to neighbouring parts, and on the other with that which penetrates between its lobules to the internal parts of the organ. On the anterior surface tjjis areolar tissue is so deficient that the structure of the gland is in no way concealed by it. Internal structure. — On cutting into the pancreas, we see that it is the same through- out its mass as it is on its surface ; that it is * Introdt ad Philosoph. Natur., p. 556. solid and homogeneous ; that one part exactly resembles another ; that there is the same aggregation of the acini into lobules and of lobules into lobes, and the same nesting in capsules of areolar tissue by the elasticity of which the acini and lobules are made to pro- trude from the cut surface, whereby it be- comes granulated and nodular ; and this irregularity of surface is almost the only difference between the appearance of a section and that of the external surface as just now described. A good idea of the absolute and relative size of the different elements may be obtained by a section : the lobes may be said to have an average diameter of £ of an inch ; the lobules J^, or \ of the lobes ; the acini TfL of an inch* ; but all the measurements are liable to the greatest variety. The areolar tissue, less abundant than in the salivary glands, consists almost entirely of the white fibrous element, and the areolae are very lax and large : it is most abundant near the centre of the gland around the duct, and about the head of the pancreas, where it forms a firm and intimate union between the gland substance and the duodenum. The duct of the pancreas, which has been called the canal of Wirsung, from its dis- covery by that anatomist in the year 1642, passes from left to right throughout the en- tire length of the organ, beginning within a few lines of its splenic extremity, by the union, at an acute angle, of two or more minute ramusculi, and emptying itself into the duodenum at or near the junction of its vertical and inferior-horizontal portions. Its course is somewhat sinuous ; it lies, on the average, about equidistant between the upper and lower margin, but nearer the pos- terior than the anterior surface. It is alto- gether concealed by the gland structure, even its point of entrance into the wall of the intestine. After originating in the manner described, it receives continuously in its course small branches which enter it at right angles, and which, unlike the main duct, are perfectly straight and not sinuous, and mostly single and unbranched, each coming from its own appropriate lobe, without receiving any accessory branches from neighbouring ones ; so that they look, as Cruveilhier has said, like the legs of a centipede, of the which the main duct forms the body. By these tributary ducts the calibre of the main canal is gradu- ally increased till it reaches a diameter, at the right extremity of the gland, of ^th of an inch. It is of an opaque white, and there- fore easily distinguishable from the gland substance. Its walls are thin and elastic, but dense and firm. In the tenuity of its walls it stands in strong contrast with the ducts of the salivary glands ; but, like them, it is con- tinuous, by its external loose fibrous coat, with the areolar tissue of the gland. Just before entering the intestine the duct com- * This last measurement is taken from the rabbit, as it is difficult to isolate the acini of the human pancreas, or to take their measurement in situ, without isolation ; but the measurement in the human subject very nearly approaches it. PANCREAS. monly receives a large tributary branch, often nearly as large as itself, coining from the head of the pancreas. This occasionally remains permanently distinct, and opens into the in- testine by a separate orifice (see Jig. 55. B, c), a condition always present, according to Fig. 55. Diagram of the principal Varieties to which the ter- mination of the pancreatic duct and its relation to the bile-duct is liable in the human subject, arranged in their order of frequency. A. The normal arrangement, showing a, the bile- duct, and b, the pancreatic, terminating by one orifice. B. Showing the separate termination of c, the ac- cessory duct from the head, or lesser pancreas. c. The main duct, b, terminating by an orifice distinct from the choledoch. D. Two parallel and equal ducts b, c, are here seen joining the bile-duct at its orifice. This is a case of " double pancreatic duct." Meckel, in the early fetus, so that this irre- gularity is essentially nothing but an exten- sion of a fetal condition into adult life. When this duplicity of orifice exists, the separate duct from the head of the pancreas has its own little papilla, proportionately smaller than the normal one, and separated from it about fths of an inch or an inch. It is usually lower down, though sometimes higher up, than the main orifice. It has been ob- served by Cruveilhier, that when there is one duct opening by a distinct orifice appropriated to itself alone, there is always another open- ing into the duodeuum in the normal way in common with the ductus choledochus. Ac- cording to other authorities*, however, the pancreatic duct and the bile duct will some- times open on the mucous membrane of the duodenum by two entirely distinct orifices, when the former is single and there is no secondary one, as seen in fig. 55. c. Oc- casionally the pancreatic duct is double throughout its whole length, the two running side by side and communicating, just before * Scemmening, Corp. Human. Fabrica. their junction, with the ductus choledochus, as shown in Jig. 55. D. Scemmerrin? asserts that there are sometimes three ducts dis- tinct throughout and opening separately. All the varieties of method of termination of the pancreatic duct have been collected and ana- lysed byTiedemann* ; and he has come to the interesting conclusion that they all have their analogues in the different arrangements found in the various species of the lower animals. The method of termination of the pancre- atic duct, and its relation to the ductus cho- ledochus, is rather curious. The duct, unlike the ducts of the salivary glands, which have a long course after leaving the gland before they terminate, passes at once from the gland to the intestine at a point where the former is closely applied to the latter, so that it is quite covered up and has no peritoneal in- vestment. At this situation it comes into contact, at an acute angle, with the ductus choledochus, which has descended to this point either in a groove of the pancreas, between it and the intestine, or in a complete channel through the gland substance. The pancreatic is placed to the left of the choledoch duct ; and, maintaining this relation, the two perforate obliquely the duodenum about the middle of its second portion and at the left side of its posterior wall. Side by side they perforate in succession the muscular, the fibrous, and the mucous coats, which they elevate into a ridge when injected or when a probe is passed into them, and after an oblique course of about eight lines, they open into the bottom of a little papilla situated in a transverse fold near the junction of the middle with the third portion of the duodenum.f In their transit through the walls of the intestine they are separated by a valve-like process, composed of the tissues that constitute their walls, which gradually gets thinner and thinner till it terminates at the base of the little olive-shaped ampulla about two lines in depth, into which the cavity of the papilla is dilated ; and since the mucous membrane lining this ampulla is of the same structure as that lining the intestine, and unlike that lining the ducts, these latter must be said to open by two distinct orifices at the base of the papilla, and not by one at its apex, as is usually described ; in fact the lining membrane of the cavity of the papilla is part of the general mucous surface of the * Sur les differences que le canal excreteur du pancre'as presente dans Thomme et dans les mam- miferes. Journal Compl. des Sciences Medicales, torn. iv. p. 370. t The point of immergence of the pancreatic duct is variously stated by various authors. Scem- merring gives it as from three to twelve fingers breadth :,below the pylorus ; Meckel, from three to four inches, but possibly amounting to ten ; Quain, three to four inches ; Cruveilhier, at the lower part of the second portion of the duodenum ; JJe Graaf, quatuor digitis transversis sub pyloro ; Gavard, five fingers breadth from the pylorus ; and so on. That given in the text, which coincides with Cruveil- hier, is the normal one ; the extremes are very ex- ceptional. G 3 86 PANCREAS. duodenum.* Towards its orifice the duct more or less enlarges itself ; but at its very aperture, on the contrary, it undergoes a contraction. The appearance of a valve guarding the orifice depends merely on the partition which separates its mouth from that of the choledoch duct. Occasionally near the orifice, occasionally higher up, there is a valve-like process projecting from its inner surface ; but this is not constant either in its situation or its existence. From the narrowness of the duodenal ori- fice of the pancreatic duct, from the movable and yielding nature of the eminence upon which it opens, and from the oblique course of the duct through the walls of the duo- denum, it follows that the pancreatic fluid and the bile may pass freely into the duode- num, but cannot regurgitate" from it into the ducts. "On this subject," says Cruveilhier -f-, "I have made several experiments. I have forcibly injected both water and air into the duodenum, included between two ligatures, but nothing escaped; on the other hand, I have injected the same fluids from the duct into the duodenum, which I was thus able to distend at pleasure. But then, on com- pressing the bowel with great force, I have never been able to cause the slightest re- flux into the ducts." The spur-like process formed by the lining membrane reflected upon itself at the junction of the ductus choledochus and the pancreatic duct, ex- tending down to the duodenal orifice, does not prevent the fluid of one canal from passing into the other. Thus the pancreatic fluid might regurgitate into the ductus choledochus, and, on the other hand, the bile might enter the pancreatic duct, if these canals were not habitually full. Moreover, this spur-shaped process between the two canals cannot arrest the flow either of the bile or pancreatic fluid, by being applied to the orifice of the one or the other duct. Fig. 56. is a diagrammatic representation of the manner in which the ducts traverse the walls of the duodenum and terminate in the papilla, and of their relation to one another, and to the coats of the intestine. Vessels. — The arteries of the pancreas, which, for the size of the gland, are large and numerous, are, like those of other conglomerate glands, contributed from many sources, and are derived from the branches of the coeliac axis, and from the superior mesenteric. The principal are the pancreatico-duodenalis of the hepatic and the pancreatic branches of the splenic artery, — one of which, the pancrea- tica magna, sometimes runs nearly the whole * Soemmerring considers the apposition of the two ducts in the wall of the intestine a junction, and the partition between them merely a valve : indeed, it is to that portion of the bile duct, so joined by the pancreatic, that he restricts the ap- pellation ductus choledochus. " Ductus choledochus, id est ductus hepaticus, cysticus, et pancreaticus in unum conflati." (Corp. Hum. Fab.) A definition as unphysiological as it is inconsistent with critical anatomy. f Descriptive Anatomy. length of the gland, accompanying the duct from left to right. The branches from the Fig. 50. Diagram of the normal method of termination of the pancreatic and bile-ducts in the human siibject, showing their oblique transit through the successive elements of the wall of the intestine, their gradual approximation to one another, their final union at the base of the ampulla or cavity of the papilla, and the spur-like process separating them, a is the bile-duct ; b, the pancreatic ; c, d, and e, the muscular and mucous coats of the intestine. superior mesenteric are mostly derived from that small twig which, given off just at the lower border of the pancreas, anastomoses with the pancreatico-duodenalis. The veins empty themselves into the superior mesenteric and splenic. The lymphatic vessels have not, that I know of, been demonstrated, nor have I been able to detect them myself: they are supposed to enter the lumbar glands in the neighbourhood. The nerves are derived from the solar plexus, and enter the gland at different parts, accom- panying the branches from the arteries of the coeliac axis. II. MICROSCOPICAL ANATOMY. Gland substance. — The subject of the micro- scopical anatomy of the pancreas is one of great difficulty, and, until I came to examine it for myself, I had no idea how great. The deli- cacy and tenuity of the structures, even when seen most advantageously ; the destruction of all their natural relations, and consequent im- pairment of the value of observations by cut- ting, tearing, or compression ; the rapid change that takes place in the microscopical elements themselves, in whatever medium they are placed for examination, by deliquescence, so- lution, or endosmosis; the conflicting character of different appearances ; and the discrepancy of many of them with the interpretations PANCREAS. 87 given by the most trustworthy authorities, all conspire to invest the practical investigation of the subject with an amount of difficulty and doubt greater, I think, than that which would beset almost any other path of micro- scopical research. And I may add to this, what would naturally be its accompaniment, a deficiency on the part of the authors that I have consulted, in that very kind of informa- tion that the practical difficulties of original research make one crave in others. The only observations on which I think reliance is to be placed for the solution of the difficulties that the examination of a structure so in- volved and delicate as the one under consi- deration presents, are observations made with the microscope on the parts, fresh, in situ, unaffected by re-agents, and undisturbed by such manipulation as shall interfere with the normal relations of their minute anatomy; and such observations I cannot find. Miiller's descriptions and drawings on this subject, in his admirable monograph, " De Glandularum Secernentium Structura Penitiori," are either taken from the parts unmagnified, or magnified with such low powers as make them valueless for the solution of the special difficulties of the case. The same observation applies to the accounts of the minute structure of the pan- creas contained in the ordinary works on de- scriptive anatomy, from their being descrip- tions of the minute structure as seen by the naked eye, or as made out by a coarse kind of disintegration, or by mercurial injections. The most satisfactory microscopical ex- aminations of the pancreas may be made, I think, from those of the Rodents; for in them the gland being spread out in its proper me- sentery in an arborescent or seaweed-like form, it is in some parts so thin as to trans- mit sufficient light for its examination without any compression or dissection whatever ; in- deed, along the edges and in some of the smallest lobules, the ultimate follicles are dis- tributed in a single layer only. This arrange- ment makes a careful and satisfactory scrutiny much easier ; and I shall, therefore, in this part of my paper, draw principally from the appearances of the gland in these animals, as the rat, rabbit, mouse ; at the same time the close approximation in ultimate structure to the human pancreas will make my observa- tions apply as well to the gland in man as in these lower mammalia. On putting a minute lobule of the pancreas of a rat or mouse under the microscope, we see a number of follicles grouped together, of various forms and sizes, constituting, by their grouping, the acini of the gland, or ultimate granules visible to the naked eye ; and when the acinus is constituted by a small number of follicles, and isolated, the whole of it may be brought under the field of the microscope at once (as in fig. 57.). These follicles are formed by the involution of the limitary mem- brane of the gland, and they contain the se- creting epithelium, and within that (at least under some circumstances) a central cavity. These elements of the follicle — the basement membrane, the epithelium, and the cavity I shall consider in succession. Fig. 57. Minute lobule or acinus of the pancreas of a Mouse, showing the two forms or stages of tlie epithelium, and the varied forms and sizes of the. ultimate fol- licles (magnified 180 diameters). a. The basement or limitary membrane. — It is to the modification and arrangement of this fundamental tissue that the pancreas (in common with all other glands, either folli- cular or tubular, simple or compound) owes its shape and appearance as a conglomerate gland, and its position in the gland series as a " compound gland with canals of the ramified type having follicular extremities."* From this membrane, as from a starting-point, the distribution and anatomy of all the other ele- ments of the gland structure proceed. The branched character of the ducts, the parti- cular manner- in which the follicles are grouped, the racemose or panniculated cha- racter of their clusters, the isolation of the epithelium within them, the amount and ar- rangement of the areolar tissue without them, and the form of the capillary network, all result from the particular way in which this basement membrane is laid down. To this simple truth anatomists have been a long time in coming. Malpighi first, in 1665, an- nounced the fact that the compound glands were mere multiplications or repetitions of the simple ones, and that all glands consisted of tubes with blind dilated or undilated extre- mities, which received the secretion from the blood and poured it into the excretory duct This view, after having some doubt thrown upon it by the researches of Ruysch and the experiments of Haller, has been entirely con- firmed and greatly elaborated by the labours of Muller, who, in his great work on the inti- * Mttller, Physiol. by Baly, vol. i. p. 444. G 4- 88 PANCREAS. mate structure of glands, has contributed more than any other author to our knowledge of this particular section of general anatomy. In the human pancreas the follicles are so closely packed that their individual shape cannot well be seen ; but in the rodents the arborescent arrangement of the gland exhibits them well ; and they are seen, when isolated, to be ovoidal or nearly spherical *, although, in the central part of the lobules they become variously polygonal from mutual compression. The outline, however, even where they are not compressed, is not that of smooth sphe- rules, but presents slight convexities cor- responding to the epithelium within them ; but the endosmosis of water, by detaching the epithelium from the basement membrane, and at the same time distending the follicle, causes these convexities to disappear. There is great difference in the size of the follicles, some being as much as ^-th of an inch in diameter, some as small as -g^o-th ; and the extremes in size will often be contiguous, a very small one packed among many large. The average size of a pancreatic follicle is about y^-g-th of an inch. The number of fol- licles in a single group varies still more, being from half a dozen to a hundred or even more. In the rodents these groups are often entirely separate from one another on every side ; but in most of the mammalia their isolation is not so complete, and they are more or less massed and fused together. Fig. 58. loose and unattached appearance, the simi- larity of their granular contents to that of the secretion when free, and the want of definite- ness of outline in many of them, which seem dissolving in their own contents, the cell-wall having disappeared, and the cluster of con- tained granules merely marking its situation. (See Jig. 57.) In neither of the stages can I detect nuclei. From the great opacity of the more advanced cells, and their grouping towards the centre of the follicle, they give a portion of pancreas, viewed with a low power, a mottled appearance, a dark spot marking the centre of each follicle, and the number of dark spots showing the number of follicles, which, in some parts, from their close packing, could not be otherwise counted When the follicles are ruptured, the epi- thelium escapes, and the two forms may be seen floating freely about. Pig. 58. repre- sents some of the more advanced cells ; they are magnified 400 diameters, and are seen to be filled with the particular granular matter which imparts to them their darkness and opacity, and which differs only from the free granular matter floating about in the secretion in being localized and confined by the vesicular envelope of the cell. What might be called the granular or molecular base of the pan- creatic fluid, is evidently the contents of these mature cells, liberated by the rupture or solu- tion of the cell-wall. The cells that have attained this appear- ance, although they may be grouped together, as seen in jig., 57. are never adherent to one another. The less advanced cells, however Fig. 59. Isolated cells of mature secreting epithelium from the pancreas of the Rat, showing their opaque granular contents. (Magnified 400 diameters.} /3. The epithelium is of the glandular type, spheroidal or polygonal in shape, varying in diameter from y-V^ri to --oVo-th of an inch, and presenting two distinct appearances, in- dicating, I think, two stages of development — an early stage, and one of more complete maturity. The cells of the early stage are smaller, more spherical, homogeneous in structure, and most abundant at the peri- phery of the follicles or in immediate contact with the basement membrane. The more advanced cells are larger, of more varied shape, full of granular contents, and loosely aggregated towards the centre of each follicle. I consider the form first described to be the early stage because the cells are so small, are in contact with or near the cell-generating surface, and are free from secretion con- tents. The others, I imagine to be the more advanced stage, from their greater size, their * In Cruveilhier's Anatomy, p. 533. note, it is said that the ultimate follicles of the pancreas are cylindrical, while those of the salivary glands are slightly dilated. ( ?) Epithelium liberated by rupture of the follicles, show- ing the method of detachment, and the nmtual lateral adhesion, of the cells. From the Mouse. (Mag- nified 200 diameters.) or those in contact with the membrane of the follicle, are often so closely adherent, that when they escape from their containing fol- licle they -form little crescentic masses, as seen in Jig. 59., the convexity coinciding with the follicle-membrane, the concavity with the central space, and the adherent surfaces of the cells presenting the appearance of radiat- ing lines, passing from convexity to concavity at right angles to them : this close package of the epithelium gives it a columnar appearance ; and, indeed, some of the little crescentic groups referred to closely resemble the scraps of sheaths of columnar epithelium shed from an intestinal villus during digestion. Sometimes, instead of the follicles being filled with distinct epithelium cells, they ap- pear to contain a number of variously-sized globules, of a smooth, homogeneous, and highly refracting appearance, surrounded by a me- dium of much less refracting power, and PANCREAS. 89 finely granular. These globules are of various shapes, according as they are isolated or com- Fig. 60. Appearance of homogeneous globules of various sizes and shapes, occasionally seen in the follicle of the pancreas. From the Rat. {Magnified 200 dia- meters.') pressed by neighbouring ones. They range in size from ^-^ to ^i. of an inch, and are evi- dently not contained in any cell-membrane. (Seejfg. 60.) The appearance, in my opinion, results from a spontaneous solution of the epithelium in the follicles, and a separation of the different elements of the secretion ; but what are the particular circumstances that de- termine it I do not know; the longer the object is kept under the microscope, the more marked is the appearance, and the larger the globules, from their running one into the other : it is possible that endosmosis may have something to do with it, for I do not remember ever to have seen the appearance in specimens promptly examined immediately after death.* 7. Occasionally there is an appearance of a central cavity in each follicle, the epithelium lining it in a single columnar-looking layer, and leaving a central space unoccupied. The central space thus left is very small, not ex- ceeding in diameter that of the thickness of the epithelial layer lining the follicle; it is only now and then that this appearance can be detected, and even then it requires careful focussing to see it satisfactorily : it may either arise from the epithelium being shed in suc- cessive generations of layers, — one passing from the follicle as the succeeding crop is produced, — or it may be explained by the mere liquefaction of the central and older cells, which, escaping in a fluid form from the fol- licle, leave the peripheral cells with a definite * Since writing the above, I have had satisfac- tory evidence that the appearance is owing to en- dosmosis. I have seen the globules form under the microscope from their first trace to their attainment of a size equal to that shown in the figure. Some- times the endosmotic current is so strong as to cause visible movement in the contents of the follicles ; the globules are the endosmosed fluid, the intervening material the granular contents of the follicle ; in fact, the secretion. I have thought it worth while to retain the figure and description, as it is an appearance that might very easily give rise to error. and even surface. At any rate, it is a rare thing to see the appearance clearly, and when it is visible, it requires accurate focussing for its satisfactory display ; for if either the nearer or more distant surface of the follicle is in focus instead of the centre, all appear- ance of cavity vanishes, and the follicle seems to be full of epithelium. Perhaps it is in part owing to this, and in part to the fact that the condition accompanies a particular and transitory stage of the secretion, that it is Fig. 61. A group of follicles from the pancreas of a Rat, viewed so as to bring their central cavity into focus. (Magnified 150 diameters.') not more frequently visible. I have repre- sented it mfig. 61., as seen in a group of fol- licles from the pancreas of a rat : it displays the proportional thickness of the central ca- vity and the epithelial lining, and shows one or two follicles, where, from being out of focus, the cavity is not visible and the follicle appears solid throughout. It was sketched immediately after death. Duct. — The duct of the pancreas, like that of other conglomerate glands, consists of three coats : a middle, elastic, dense, fibrous, and white ; an external, loose, and areolar ; and an internal epithelial. Between the middle and internal there is probably a basement mem- brane, described, indeed, by some authors, but which I have been unable to detect. The middle coat consists of a firm, dense, and matted stratum of fibrous tissue, mainly longitudinal in direction, but closely inter- woven and netted together, very much re- sembling white fibrous tissue in appearance, but evidently not consisting of this entirely, as the striation is not removed by acetic acid. A certain amount of clarification, however, is produced by adding the acid, and the fibres that remain visible afterwards appear to con- sist of a particular form of yellow fibrous tissue, extremely fine, so as to lose the cha- racteristic appearance of double outline and even calibre. These fibres are exclusively longitudinal and parallel, except towards the outer surface of the duct where they inter- lace. Besides these, acetic acid displays, irregularly and sparingly scattered, some trans- verse and some longitudinal, the nuclei of some unstriped muscular fibres. These fibres I have never been able to isolate or see satis- factorily, for the density and opacity of the fibrous tissue previous to the addition of acetic acid renders them invisible : they lie near the inner surface, and, from the paucity of the nuclei, must be very few. The external coat is merely the loose areolar web which connects the duct to the 90 PANCREAS. gland substance, and is continuous with that which pervades the whole gland : it differs not, therefore, from that which has been already described. Fig. 62. Tesselated appearance of columnar epithelium lining the pancreatic duct. {Magnified 200 diameters.) The epithelium is columnar, arranged ap- parently in a single stratum, and presenting a beautiful honeycomb appearance of closely- packed hexagons and pentagons, when looked at on its free surface. Further up, however, near the extremities of the ultimate ducts, the epithelium changes its character, and becomes more globular, as is shown in Jig. 63, which represents a portion of the epithelial lining of a duct, about 7^ of an inch dia- meter, from the human subject. A certain ap- proximation is here seen to the form of se- creting epithelium, with which, however, it strongly contrasts in its clearness and free- dom from granular contents. Fig. 63. Portion of epithelium lining a small duct ^th of an inch in diameter. From a Babbit. (Magnified 300 diameters.) There is every probability of the existence of a basement membrane here as in other sub-epithelial situations, and it is probably continuous with that which alone constitutes the walls of the ultimate ducts : for the fibrous and muscular elements gradually diminish as the ducts get finer, until in the smallest that are seen all fibrous appearance has vanished, and a homogeneous membrane alone remains. According to Henle the homogeneous wall of the smallest ducts consists of fibres fused and run together in a plane ; — a supposition that would imply the non-existence of this mem- brane in the larger ducts, where they are not so fused. Capillaries. — The arrangement of the ca- pillaries remarkabfy resembles that of fat. They form a close and pretty even-meshed net work, open on all sides, among the meshes of which the follicles lie, just as the vesicles do in the case of fat ; so that the closeness of the plexus is a measure of the size of the follicles. Their general appearance is well seen in the accompanying figure (fig. 64.). Fig. 64. Arrangement of the capillaries of the pancreas. From a minute lobule of the pancreas of a young Babbit. (Magnified 80 diameters.) III. COMPARATIVE ANATOMY. Invertcbrata. — Certain organs connected with the alimentary canal have in some of the higher invertebrata received the name of pan- creas ; but they have done so rather from their position and inferred function than from any certain evidence of their use, or from their anatomical structure. In Gasteropoda we find the first indications of the organ, and it presents in them the form of a single, long, blind, glandular sac, communicating with the beginning of the intestine ; such a pancreas may be seen in the different species of Aplysia and Doris, Tritonia and Scyllaea. Cephalopoda. — The Tetrabranchiate Cepha- lopods possess, attached to the upper part of the intestine, a laminated sac, which receives the canal into which the two main hepatic ducts unite, and which diverts the bile by a peculiar development of one of its laminae, from flowing into the gizzard. Professor Owen considers that the follicular structure of this and the other folds of membrane sufficiently indicate its glandular character, PANCREAS. 91 and regards the entire laminated pouch as a more developed form of pancreas than the simple caecum, which we have just described as representing that gland in some of the Gasteropods. Vertebrata. — Fishes. — At the commence- ment of the intestinal canal, close to the pylorus, are found, in most osseous fishes, certain caeca or blind tubes, budding out from the wall of the canal, which from their position have received the name of pyloric appendages, and have been regarded by most anatomists as the analogue of the pancreas in higher animals. In their most simple form — that of a single, or two or three short buddings of the intestinal wall, not differing from it in the structures that form them, the analogy would hardly suggest itself, but by gradual steps we are conducted from this simple re- presentative of the organ, through a series of forms of increasing complexity, to a structure bearing some analogy to a conglomerate gland, and at any rate deserving to be considered a special glandular appendage to the alimentary canal; the caeca becoming more and more numerous as we ascend in the scale, and the whole organ more and more concentrated. Thus in the Sandlance (Ammodytes lancea), and Polypterus there is but one pyloric cae- cum ; in most of the Labyrinthibranchs, in many species of Amphiprion, in the Angler (Lophius piscatorius), Turbot (Pleuronectes •dura***), and Mormyrus there are two ; in the Perch(PercaJtuviatilis),the percoid Popes, the Asprodes and Diploprions, three ; in the Miller's Thumb (Coitus gobio), and Father Lasher (Coitus scorpitis), from four to nine ; in the Gurnard (Trigla), from five to nine ; in Scorpaena and Holocentrum, six and up- wards ; in the Pilchard (Cupea pilcardus), and Lump-fish (Cyclopterus lumpus), there are fifty, and upwards of fifty in the Tunny (Scomber thynnus] ; in the Cod (Gadus mor- rhua\ there are upwards of 120 : and in the Sturgeon (Acipenser sturio} and Paddle-fish they cannot be counted.* But the increased complexity, and divergence from the simple caecal form, is not produced only by the greater number of the appendages. As they increase in number, they more and more coalesce at their bases, so that many caeca open by few orifices, and thus the character of the gland is gradually changed, becomes clustered and branched, and passes from the tubular to the racemose type. Thus, in the Pilchard, fifty tubes communicate with the intestine by thirty orifices; in the Lump-fish the same number by six ; in the Tunny, by five ; in the Sword-fish (Xiphias gladius}, there are but two orifices ; and in the Stur- geon, the whole mass of caeca, by continually uniting and re-uniting, come at last to empty themselves into a single tube, equivalent, in fact, to a short and wide pancreatic duct. The reasons which have induced anato- mists to regard this organ as the analogue of the pancreas are these. * Owen's Lectures on Comparative Anatomy. In the first place, the situation; it is placed at the pyloric extremity of the intestine ; and besides this general similarity in situation, there is this special one, that the hepatic duct has the same relation to it as it has to the pancreas in higher animals. If there is but one orifice, as in the Sturgeon, the hepatic duct opens at its base; if many, at the base of one of them. Secondly. If they were merely multiplica- tions of surfaces to which food was to be ex- posed, we should find food getting into them; but this is never the case. I have not been able to detect any alimentary materials in even the largest of them ; their function there- fore must be that of pouring forth some special secretion. Again, it is not the way, the particular method, in which surface is multiplied ; that is done by modifications of the lining mem- brane of the intestine, the mucous structures, alone— by folds, villi, crypts — and not by extension of the whole intestinal wall, mus- cular and sub-mucous, as welL Lastly, the filling up of all the intervening stages from simple tube to conglomerate pan- creas goes a great way to prove the essential identity of the extreme forms. But what is very remarkable with regard to these appendages is their entire absence in many classes of fish. In all the Abdominal Malacopterygii, except the Salmonidae and Clupeidae, they are wanting ; in most of the Labroids, Gabioids, Cyprinoids, and Lucioids, they are absent ; in the Apodous Malacop- terygii, in the Lophobranchs and Plectognats there is no trace of them ; nor in the genera Antennarius, Malthaeus, and Batrachus. In some cases they appear to be wanting in con- sequence of their place being supplied by a more elaborate mucous surface, as in the highly developed stomach of the Anarrhichas, and the glandular palate and long intestine of the Caiff(Cypn*xt)i in others, their absence seems to be but a part of a general simplicity of the alimentary apparatus, as, for instance, in the Dermopterous fish. In the Eel, where there are no caeca, the mucous membrane at the pylorus suddenly becomes thick, vascular, and spongy, and continues so for about an inch ; and on pressure an abundant secretion may be squeezed out of its wall, of an appearance exactly identical with that found in the pyloric appendages where they are present. It is difficult to seize on the law of their existence ; we may, however, say that they are, for the most part, wanting in fish that live on vegetable substances, although there are many similarly circumstanced that are carnivorous and very voracious. Their de- velopment, or their relative size, their number and complication, are probably in proportion to the activity of digestion and rapidity of growth ; the Salmonidae, the Clypeidae and Scomberidae, seem to indicate this : in these last these pyloric caeca exhibit a remarkable complexity. In the Turbot (Pleuronectes mcunmus) these caeca are seen in their most rudimentary 02 PANCREAS. form; they are two in number, ample, conical, 66.) : the upper five unite together at their and recurved, projecting back from the duo- bases, and open into the duodenum, close to denum at its very commencement, so as to give it a barbed or arrow-head appearance, as seen in the drawing (Jig. 65.). The stomach in this fish is very small, and the duodenum Fig. 65. Pyloric caeca of the Turlot. a, oesophagus ; b, stomach ; c, intestine. (Drawn one -third the natural diameter.) very large, and the food probably passes into the intestine with but little delay. The caeca in this case must be considered an exception to the rule I have above laid down, that they are never filled with the contents of the alimentary canal ; for in the specimen I examined they were completely stuffed with taeniae, with which also the intestine was filled. Fig. 66. Pyloric caca of the Sprat (Clupaa sprattus). a, oesophagus ; 6, stomach ; c, intestine. (Na- tural size.) In the Sprat, the pyloric caeca are nine in number, long, slender, and simple (see fig. the pylorus by one orifice ; the last four open separately, each by its own orifice, in linear series along the duodenum. In the Gadidce, as in the whiting (Jig. 67.), the caeca are arranged in the form of a ring, Fig. 67. Alimentary canal of the Whiting (Merlangus vul- garis), showing the pile of ca;ca around the pylorus. (One lialfthe natural diameter.) constituting a frill around the intestine, and consits of four bunches, each containing about thirty caeca. These unite and re-unite till they terminate, each bunch, in a single duct ; so that there are finally four orifices, so placed as to fall on two converging sides of a triangle, of which the orifice of the hepatic duct would form the apex. As each bunch contains thirty caeca, there are a hundred and twenty Fig. 68. One of the four bunches of pyloric appendages of the Whiting, isolated; showing their union and reunion till at length they end in a single tube. PANCREAS. 93 Fig. 69. in all. The appearance of the frill of pyloric increase in length from the first three down- caeca is shown in fi". 67, and one of the wards, and the third from the stomach is bunches separate in fig. 68. generally the longest. They then gradually In the Salmon this apparatus of caeca is dimmish, slightly in calibre, considerably in much more voluminous. It is not condensed length, to those furthest down the intestine, around a particular portion of the intestine, which are about three inches long. Altogether but extends linearly, from close to the duo- the secreting surface of these caeca must con- denom for a distaiice of about eight inches siderably exceed that of the rest of the ali- along the intestinal wall ; each caecum opens mentary canal, and the whole apparatus, taken by its own separate orifice. There is no together, is next to the liver, by far the coalescence or fusion, so that on looking on largest of the viscera. Each double row con- the inside of the intestine there are seen as tains about thirty, so that altogether thecc many orifices as caeca ; they form a double are sixty caeca, and as the average length of row on each side, so that altogether there each caecum is 6£ inches, the whole length are four rows, and are arranged with the of secreting surface must be 390 inches, or utmost regularity. The amount of secreting upwards of 32 feet. surface of these caeca must be very great; In their internal ultimate structure these caeca some of them are ten inches long, and as exhibit considerable variety ; in many the mu- bi" round as a tobacco-pipe; they rapidly cous surface is closely laminated ; in some it is covered with flattened, fused villi with crypts thickly planted between their bases. In the Herring (fig. 70.) the structure is very peculiar : on looking vertically on the internal surface it is seen to be mapped out into hexagonal and pentagonal cells about T^ of an inch in diameter, very evenly and geo- metrically arranged, and each filled with a mass of epithelium. The septa between them appear to consist of sub- mucous fibrous tissue, and on making a section and looking at it laterally they are seen to project between the acervuli of epithelium, and rather beyond them, and to have no epithe- lial investment of themselves. The masses of epithelium are seen to be of a spheroidal form and very smooth outline, though I could not distinguish any basement membrane or capsule wall of which they might be supposed to be the contents, or any special structure determining their outline. I have thought this structure suffi- ciently peculiar to give a figure of it. A represents the appearance on looking down on the surface; B, a view of the wall in section, seen with a lower magnifying power. Many anatomists deny the true pancreatic nature of these pyloric caeca, and assert that many fish pos- sess, over and above them, a true glandular pancreas, analogous in struc- ture to the pancreas of higher animals. Weber first described such an organ in the carp, as interlaced with the lobules of the liver, and, so to speak, confounded with them, but having a proper excretory canal opening into the intestine by the side of the cystic ; he also thought that he had seen traces of a pancreatic duct in the pike. Much more recently Alessan- drini described the same excreting duct, as also the volume and position of the pancreas, in the same fish. In the Silurus g/anis MM. Brandt and Portion of the alimentary canal of the Salmon (Salmo solar), showing one double row of ccecal appendages and the pyloric extremity of the other. a, oesophagus ; b, stomach ; c, pylorus ; d, small intestine ; e, gall-duct. (One-third the natural diameter.) KutzeboLirg have taken for the pan PANCREAS. creas a glandular body very like the liver in appearance, stretched as a layer between the Mucus membrane of the interior of the pyloric caecum of a Herring ( Clupcea harengus). A, the surface seen vertically, showing the honey- comb appearance formed by the septa separating the masses of epithelium. (Magnified 150 dia- meters.) B, a section vertical to the surface, showing the flattened spheroidal shape of the acuvuli of epithe- lium, and the amount of projection of the septa between them. (Magnified 60 diameters.) folds of thegastro-hepatic omentum, enveloping the cystic canal and accompanying it as far as the intestine. These three examples of mala- cocopterygious fish have no pyloric caeca, and this glandular structure might be considered as replacing them ; but Alessaudrini has also de- scribed in the sturgeon, the walls of whose in- testinal canal are particularly glandulous and in which the pancreatic caeca form an elaborate apparatus, a proper pancreas with an excretory duct opening into the intestine in the middle of a tubiform papilla about an inch from the pyloric orifice. In this last case Cuvier be- lieved tbe bod}' indicated as the pancreas to be a lobe of the liver. " The tubiform pa- pilla," he says, " truly exists ; indeed I have found two, besides that appertaining to the choledoch duct. In one of the examples it formed a sort of cul-de-sac ; in the other the fibre which was introduced conducted to a canal which took a direction towards the liver. I have clearly seen an excretory duct in a very large silurus, piercing the intestine of the s'ide of the choledoch ; but that canal was, in my opinion, hematic, for the glandular substance taken as tbe pancreas was evidently continuous with the right lobe of the liver, and formed, as it were, a middle lobe ; its appearance was in other respects the same, except that its colour was rather clearer in consequence of its substance being less thick at that part. The duct discovered in the pike certainly exists, as far as my re- searches go ; but that, again, is an hepatic canal, for I have not seen any body distinct from the liver from which it takes its origin, or which could be considered as a pancreas. The same must be said of the carp, where Meckel could discover neither a pancreas nor pancreatic duct, in spite of the indications of Weber." Still more recently Stanmus lias enumerated many fish in which a parenchy- matous pancreas may be found ; but the de- scription added to his enumeration is so meagre and general that nothing can be veri- fied upon it. Rcptilia. — In the reptiles we make a great approach to the structure of the pancreas of higher animals both in general form and struc- tural appearance. It exists in them all, and generally maintains that intimate relation to the end of the stomach and commencement of the intestine which we see so constant in birds and mammalia. In the Batrachia, the pancreas is situated in a proper mesentery or meso-gastrium of its own, extending between the "lesser cur- vatur of the stomach and the duodenum, and, according to Cuvier, is more developed in terrestrial batrachians than in aquatic, in those that take their nourishment out of the water than in those that hunt and seize it in the water. In the Frog (Jig. 71.) the pancreas is shaped not unlike that of the human sub- ject, but its broad end is in the opposite position ; it is about three quarters of an inch long, weighs '27 of a grain, and is of a yellowish white colour and soft consistence; it is in close apposition with the duodenum all the way Fig. 7 1. Pancreas of the Frog, shown by throwing up the stomach, and exhibiting the under surface of the tnesogastriutn. a, oesophagus ; b, stomach ; c, pylorus ; d, duo- denum ; e, small intestines ; /, liver ; p, pancreas ; s, spleen. (Natural size.) along. From near the large end it sends up a process clothing and concealing the gall duct as far as the gall bladder, the neck of which it invests. The whole of the gall duct, till the point of its immergence into the in- testine, is thus concealed in the substance of the gland, and it might at first sight be mis- taken for the pancreatic duct ; but, by care- fully nicking it and introducing a fine hair, the hair may be passed up to the liver. The most careful dissection could not reveal a proper duct ; probably small ducts from different PANCREAS. 95 parts of the gland open into the biliary duct as it passes through. The organ maintains the same relations in the Toad ; in the com- mon toad it is yellow, straight, and elon- gated. In the Tritons it is perceived with difficulty; Cuvier describes it as appearing like a semi-transparent riband sending one bifurcation to the spleen, and another to the duodenum at the point of insertion of the biliary canals. In the Siren it resembles in miniature, as far as external appearance goes, the pancreas of the sturgeon, and joins the intestine by many parallel canals considerably in front of the cystic. In Ophidian reptiles, the pancreas varies greatly both in volume and form ; sometimes it is elongated, often globular and pyramidal, sometimes divided into two triangular lobes, and this variety of form obtains even in con- generic species ; thus, in the Ccecilia albi- ventrii it is thick, and pyramidal, and in the Cfecilia intcrrupta, lumbrico'ides, and den- fata, it is straight, elongated and slightly forked. It is always placed to the right of the commencement of the intestinal canal and head of the stomach. Its substance is red with a tint of yellow, and soft, more rarely firm and consistent, and often divided into distinct lobes. In this respect it does not at all resemble the salivary glands of these ani- mals, but those only of mammifera. Its inti- mate union with the spleen is very remarkable in the true serpents, whilst in the genus Anguis and CfEcilia the contact and adhesion at this point does not exist. In the Saurian reptilia the pancreas is often applied against the pyloric portion of the stomach and the commencement of the duo- denum ; or it may be said to have two branches parallel to the stomachal sac, one of which accompanies the biliary canal, and the other adheres to the spleen, and these reuniting terminate at a point more or less approaching the pylorus ; it is almost always contiguous to the choledoch canal, which often traverses it before arriving at the intestine. According to Cuvier, its volume is greater in saurians living on vegetable food ; and its smallness in those that are carnivorous he believes to be com- pensated, as in fish, by the agency of the mucous and intestinal secretion of the abun- dant glandular apparatus with which their alimentary canal is furnished. In the Lacer- tidce, and Iguanidcs, the pancreas is very much developed. Chelonia. " In many respects," says Cuvier, " the animals of this order are in the same conditions as birds. The jaws are similarly armed, the salivary glands are but little de- veloped, and as the volume and importance of the pancreas in birds has appeared to us to be in inverse ratio to the means of masti- cation and insalivation, we might antecedently conclude that the chelonia would also pos- sess a considerable pancreas." At the same time he adds, that the superior masticatory power of the horny jaws of the chelonia over the bills of birds, and their taking their prey generally in the water, considerably impairs the closeness of the analogy. In the com- mon turtle^ the pancreas (j%. 72.) firmly ad- Fig. 72. Pancreas of the Turtle, with the duodenal curvature thrown up, shouring its loose and branched cha- racter, its embrace of the spleen, its long caudate process accompanying the duodenum, and its duct entering the intestine higher up. s, spleen ; m, branch of superior mesenteric artery ; c, gall-bladder. heres to and embraces the spleen ; from that point it radiates towards the duodenum, being thick, amassed, and irregularly arborescent above and to the right, and continued in a long and tapering tail to the left : it is closely attached to the duodenum along its whole extent, a distance of about fifteen inches. The duct, nearly as large as in the human subject, passes to the right, and enters obliquely the choledoch duct, as that canal is perforating the thick intestinal wall, in a way very analogous to that already described in the human sub- ject. The gland substance has a very peculiar appearance ; it is dense, opaque, nearly white, and along its edges the lobules are scattered in the clear gelatinous-looking cellular tissue in which the gland is embedded, and appear to be quite distinct from each other ; but on dissecting them out from this gelatinous bed, they are seen to be attached by little pedicles — in some of gland substance, in some apparently merely of the duct of the lobule and its vessels — to the rest of the gland. It is the most arborescent and ramified pancreas I have seen, next to the rodents, but not so flattened, nor spread out so much in one plane. When looked at as an opaque object with a low power (one inch focal distance), the mapping out of the follicles is very prettily seen ; but the same circumstance that lends them their 96 PANCREAS. white opacity, — their fulness, that is, of a densely opaque granular material — prevents their being seen to advantage as transparent objects, or with a high power ; they are so opaque that nothing of their structure can be distinguished. When ruptured by pressure, their contents escape, and are seen to consist of two very distinct materials ; one, the afore- said fine granular matter ; the other of clear, spherical, uninuclear cells of about ^J—Q of an inch diameter. One would imagine ante- cedently that these would hold the relation to each other of secreting epithelium and elaborated secretion ; but the cells are so clear, so free from granular contents, and there is such a complete absence of any intermediate appearance, that I am at a loss in what way to interpret them.* The duct opens by a single orifice, and in a way admirably adapted for preventing the regress of the secretion, or the entry of the contents of the alimentary canal into it. If the aperture in the centre of the papilla by which the bile duct terminates is opened up, it is found to lead into a lacuna, or cul-de-sac, of about half an inch in length, embedded obliquely in the walls of the in- testine. At the bottom of this lacuna is a second papilla, the real termination of the pancreatic duct. Now, if the movableness of the external papilla and the smallness of its aperture were not sufficient to prevent the ingress of the contents of the alimentary canal, yet the very force that might drive in some of these contents through the outer papilla, would press the walls of the lacuna firmly against the orifice of the internal one, and so effectually close it ; nothing could be more efficient than this form of double orifice. The duct in all reptilia always enters the duodenum, generally separate, sometimes in conjunction with the choledoch, and is almost always simple. Aves. The pancreas of birds is propor- tionally larger than in any other animals ; and when we remember their deficiency in salivary apparatus, its great development would at once suggest a function, in some degree, at least, supplementary to those organs. An- other circumstance peculiar to birds and in- dicative of the importance of the part that the gland plays, is that the ducts are generally many, two and three, and that they open by separate orifices, and often at a considerable distance from one another ; so that the secre- tion may be poured forth on different and widely separate portions of the alimentary con- tents at one and the same time, a circum- stance that must greatly increase and expedite its action. Birds, we know, seize and swallow their food generally without any mastication, and therefore it is not until it gets to the gizzard * The follicles appear to contain only the granular material, and in a minute duct I saw a number of the nucleated cells. It is possible that they may be a form of epithelium restricted to the terminal ducts, by whose rupture and compression they escaped, as the granular matter did from the fol- licles. that it is subjected to any mechanical force capable of breaking it up. This, therefore, takes place immediately before entering the duodenum, and this throws the function of mastication close down to the pancreas, so that from its situation, as well as in other respects, it should have an insalivating function. It is always enclosed between the two arms of the duodenal flexure (Jig. 73.); the duo- Fig. 73. Pancreas of the common Goose (Anas anser), show- ing its relation to the duodenum, its duplex form, and its ducts. (Natural size.} denal portion of the gland being, so to speak' alone developed. It is retained in this posi- tion by the gastro-hepatic and gastro-colic omenta, which sometimes simply attach it to the border of the intestine, and sometimes allow it to be free and floating. There is considerable variety in its shape, but it is always more or less elongated and slender : sometimes it is undivided and single, in some species deeply cleft, in others consisting of two portions, or a double pancreas, quite dis- tinct, each having its own duct ; sometimes it is divided into three as in the pigeon. But PANCREAS. 97 these arrangements are liable to considerable variety, and perfectly independent of the in- timate structure and function of the gland, for in different individuals of the same species, the arrangement of the ducts is generally the same, however the segmentation of the gland may vary. The gland substance is firm, much more dense than in other orders, and not di- vided so distinctly into lobes and lobules : it has a finely granular and mottled appearance, in colour pink, or a little yellowish, or brownish. The pancreas seldom communicates with the intestine in birds by a single canal, the ducts are generally either two or three in number, and each continues independent and separate to its orifice. They do not communicate either with one another or with the biliary canal : although, however, exceptions are very rare, Cuvier has met with an instance in the stork, in which the single pancreatic and hepatic ducts united and opened by a common orifice. The following table, altered from Cuvier, shows the number of the pancreatic ducts in several orders of birds, and their relative si- tuation with regard to the hepatic and cystic ducts ; it also shows the relation of these last to one another. That canal which is first indi- cated has its insertion the nearest to the py- lorus ; P. stands for pancreatic, H. for hepatic •, and C. for cystic. We see from this table, that, as a rule, the 1. RAPTORES. Brown Vulture Common Eagle Golden Eagle Aquila Ossifraga - Owl - 1 P. H. H. 1 P. IP. H. P C. H. 2 P. 2 P. C. P. 2 P. 3 P. 3 P. 3 P. H. C. C. C. Duv. Duv. ! Cuvier. Perrault. Cuvier. Night -jar - - I H. Crow - - - I IP. Picus (Genus) - 1 P. Green Woodpecker 1 P. Parrot - - 1 H. Blue Macaw 1 H. II. ISSESSORES. P. C. 2 P. H. C. III. SCANSORES. 2^P. 3 P. 2 P. 3 P. C. 1 P. 2 P. 2H. V. GRALLATORES. VI. NATATORES. Grebe Great Diver Apterodytes Gull - Petrel Swan Duck 3 P. C. H. Cuvier. Cuvier. Meckel. Cuvier. Cuvier. Duv. IV. RASORES. Crax (Genus) 1 P. 2 P. 1 H. 2H. Perrault. Crax Globicera 1 P. 2 P. C. 1 H. 2H. Perrault. Common Cock 1 P. 2 P. 3 P. H. C. Duv. Quail -.- P. H. C. Cuvier. Pigeon 1 H. 1 P. 2 P. 2H. Duv. Bustard 1 P. 2 P. H. C. Perrault. Ib. 1 P. 2 P. 3 P. H. C. Meckel. Cassary P. C. H. Perrault. Rhea Americana - H. P. C. Meckel. Ostrich H. P. Perrault. Stork P. H. C. Cuvier. Bittern H. P. C. Duv. Heron 1 P. H. 2 P. 3 P. C. Cuvier. Grus pavonica 1 P. H. 2 P. C. Duv. Grus virgo 1 P. 2 P. H. C. Perrault. Curlew H. C. Duv. Ib. - 1 P. 2 P. H. C. Cuvier. Gold-headed trum- Duv. peter IP. H. C. Flamingo 1 P. 2 P. 3 P. C. H. Cuvier. Ib. - - - 1 P. C. H. Meckel. Parra Jacana H. 1 P. 2 P. Cuvier. 1 P. 2 P. 3 P. H. C. Meckel. C. H. P. Duv. 1 P. 2 P. H. 3 P. Cuvier. 1 P. 2 P. H. 1 C. 2C. Meckel. 1 P. 2 P. H. C. 3 P. Meckel. 1 P. 2 P. H. C. Cuvier. \ P. 2 P. H. C. Duv. 98 PANCREAS. pancreatic secretion is the first poured into the intestines, and the cystic bile the last : and always when there are three pancreatic ducts, the secretion reaches the intestine early by one of them, and the others have their openings close to the bile ducts, either before or between them. It is not safe, however, to draw any physiological conclusions from these relative positions, even supposing them to be constant ; for the ducts are so close to one another, that the mixture of the fluids must take place immediately, and their action on the food be simultaneous. In one instance, however, this is not the case ; in the ostrich the bile duct opens close to the pylorus, while the pancreatic is three feet removed from it ; this is the greatest separation of the two ducts of any with which I am acquainted in the animal kingdom. It would present, if ostriches were commoner birds, great facilities for ex- periment, and implies an action in both the secretions entirely independent and auto- cratic. Mammalia. — The chief differences between the pancreas in other mammalia and man re- late merely to its colour, its consistence, its more or less marked division into lobes, its form, its volume, its union into a single mass, or its separation into two distinct parts, lastly, its position and relations with different por- tions of the peritoneum. Its form is generally more or less that of a narrow band, divisible into two portions ; one, the duodenal, following the curvature of the duodenum, and placed vertically or obliquely; the other, gastro- splenic, extending transversely, and therefore opposite the other, from the duodenum to the spleen, against which it always abuts; the latter is always developed, the former is often incon- siderable or suppressed, and must be con- sidered merely as an accessory portion. The various forms and arrangements of the pancreas do not appear to have anything to do with it? essential structure or function, or the parti- cular exigencies of the animal ; they seem to depend entirely on the relations of the neigh- bouring organs, the presence or absence of an abundant mesentery, the free movement of the duodenum, &c., and to be influenced by con- siderations of package. In the Ourang the form very much resem- bles that of man ; in most other Quadrumaiia Fig. 74. Pancreas of the Rat (natural size), shown by throwing up the duodenum, together with its proper mesentery, and the free process of peritoneum ex Ending thence to the left, in which the gland ramifies. Its arborescent form and great extent are well shotvn. PANCREAS. 99 it is irregular. In the Carnivora it is always large in proportion to the size of the animal*, both the duodenal and gastro-splenic portions being highly developed. In the ox, from the distinctness of the two portions, the organ has a bilobed appearance. In the horse, from the gastro-splenic portion being double, it has a trilobed form. But the most remarkable pan- creas is that of the Rodents; it is spread out in an arborescent manner, in an extensive mesen- tery that imparts free movement to the long duodenum, and extends towards the left in a sort of omentum, which underlays the stomach. (Fig. 74.) Confined thus between the two layers of a mesentery, the ramified lobes of the pancreas lie all in one plane. Although their distribution is somewhat irregular, they more or less radiate in their general direction from the point at which the duct enters the intestine, which in the rabbit is nine inches or a foot from the pylorus. That part of it which occu- pies the duodenal mesentery must be consi- dered the representative of the duodenal por- tion, and that spread out in the omentum underlaying and attached to the stomach, as the gastro-splenic. Altogether, this arbores- cent pancreas of the Rodents is very volumi- nous, particularly in the rat, from which the drawing was taken. The pancreatic duct has in Mammalia gene- rally the same branched character as in man, the greater and lesser branches corresponding to the lobes and lobules ; usually there is but one orifice, rarely more, and most commonly it enters the intestine near the pylorus, although sometimes a great way removed from it. In most of the Carnivora it is, as a rule, united with the choledoc duct : in some cases it pre- sents at the point of its immergence into the intestinal canal a sort of ampulla, in which the secretions probably mingle before their entry into the intestine. There are, however, con- siderable varieties of insertion — in the lion two pancreatic ducts join the choledoc sepa- rately, one near the other. But whether the ducts enter bv a common orifice, or by two neighbouring ones, or whether there are one or two pancreatic ducts, has, probably, no physiological import whatever, as it cannot make any difference whether the secretions are brought into contact just before or just after entering the bowel ; and this belief of the non-essential character of these varieties is strengthened, or rather proved, by their oc- currence in closely allied species of the same genus, and even in different individuals of the same species. Cuvier says that he has ob- served, although very rarely, in the domestic cat, a lateral reservoir for the pancreatic secre- tion, analogous to the gall bladder. Its duct, about the size of the cystic, was an inch and a half long before it united with a trunk formed by the union of two pancreatic ducts, a prin- cipal and an accessory, and, together with this, formed a common duct analogous to the ductus communis choledochus. Tiedemann has de- tected a similar pancreatic reservoir in the * See the physiological portion of this article, page li' l. common seal. The greatest distance from the pylorus at which the pancreatic duct enters the intestine occurs, I believe, in the Rodents. In the rabbit this distance amounts to a foot or upwards; and this arrangement, by giving a considerable length of small intestine whose contents are not acted on by the pancreatic secretion, has afforded special facilities for ex- periment. III. PHYSIOLOGY. Anatomy always implies physiology, — structure, function ; and the mind passes from the one to the other by a ready and almost irresistible transit. In fact, organisation is but the accumulation, in certain parts, of certain material agents, the sum of whose common action gives as its result the func- tion of the organ, and both the nature of the elements so accumulated, and the method in which they are built up, are determined by, and have sole reference to, the work to be done. Physiology invariably stands to anatomy, even in its ultimate and minutest details, in the relation of final cause. Now, there are certain anatomical conditions that always indicate physiological importance ; among these are volume and constancy, — constancy in existence, and constancy in structure. In all these respects we should be led to infer from the consideration of the anatomy of the pancreas that it possesses essential functions ; for it is always of con- siderable size, has a very wide range of exist- ence, throughout the whole of Vertebrata, from the lowest fish to the highest mammal, and is analogically represented in many In- vertebrata ; and, lastly, in structure it exhibits with very few exceptions, throughout this wide range, a remarkable sameness. The opinions entertained by the old ana- tomists with regard to the office of the pan- creas were many and various. The earliest anatomical writers do not seem to have been aware of its existence*; some thought that its object was to underlay the stomach as a cushion or pillow, and to serve for the dis- tribution of vessels ; others, that it admitted the chyle from the intestines ; others, that it purified the dregs of the chyle ; others, that it served for the spleen a purpose ana- logous to that of the gall bladder for the liver ; others, that by it were thrown off the gross and used-up dregs of the blood ; others, that the organ was formed for the reception of the excretion of the nerves ; others, finally, taught that the pancreatic secretion was not only useful, but played a vital and essential part in the organism. The first opinion, which was of very ancient date, was held by Vesaliusf ; but it is at once refuted by a reference to those animals, birds and fish, for example, in which the pancreas is frequently remote from the stomach. The second view, that the pancreatic duct admitted the chyle from the intestines, is assigned to Baccius and Folius, who both maintained that it * Hippocrates nowhere mentions it. f De Humani Corporis Fabrica, i. 5. cap. 4. De Omento. H 2 100 PANCREAS. served for the transit of the chyle from the intestine to the liver and spleen. Very early investigation, however, showed the fallacy of this view, as it proved that the fluid of which the pancreatic duct was the channel always passed to the intestine and never front it. The fourth opinion is ascribed to Ves- lingius, who says, in speaking of the pan- creas*, Usus hujus canalis obscurus non est, ncnn cum acrem quendam fellique non dissi- milem succum exhibeat, palam est excreinentum tale, per coctionem ulterior em a chylo separatum, allici infra hunc atque in duodenum intcstinum expurgari. This view, which is simply re- futed by saying that the secretion obtained from the pancreas does not in any way resemble bile, that it is not " felli non dissimilem," was supported by Asellius. Riolanus, and others. De Graaf accounts for it by supposing that the tube introduced into the duct for the purpose of obtaining the secretion became covered with the bile accumulated about the common orifice of the two ducts, which it might very well do, either on being inserted or withdrawn, and that this, becoming mixed with the pancreatic secretion which it had withdrawn, gave rise to the erroneous opinion that that secretion had a resemblance to bile. The fourth opinion, that the pancreatic duct was the excretory canal of the spleen, which was maintained by Bartholini, is refuted by the simplest anatomical considerations, and was further disproved by De Graaf, who, to show its fallacy, extirpated the spleen of a dog, and, two months after the extirpation, obtained the pancreatic secretion unaltered. The fifth view was based on similar supposed anatomical relations between the pancreatic duct and spleen. It is assigned to Lindanus, and was refuted by the same considerations as the last. The theory that the pancreas carried off the excretion of the nerves was based on the old view that the nerves distilled the animal humours and spirits. AH these views are perhaps rather amusing than in- teresting, and are among the curiosities of science. They show us how much our me- dical forefathers were disposed to take for granted, and how disposed they were to run alone when the shell was still on their heads. The true doctrine that the pancreas furnished an important secretion of its own was first advocated by Francois de le Boe Sylvius -f-, who first insisted on its acidity, and who at- tached great importance to its pathological conditions. Indeed, he made its derangements the cause of nearly all the ills that flesh is heir to ; in the same way that Spigelius did his lobe of the liver. It was in consequence of the interest which the lessons of Silvius excited that De Graaf, his pupii, undertook his admirable researches De Succo Pancrea- t>co, and succeeded, in 1662, in first obtaining the pancreatic secretion from the living ani- mal : the most important point was thus ascertained, and the materials supplied for further investigation. * Syntagma Anatom. cap. 4. t Tlies. 37., De Usu Lienis et glandular. With the view of obtaining the fluid, De Graaf first put a ligature round the duo- denum, including part of the pancreas, but failed in obtaining the desired result, in con- sequence, as he imagined, of the ligature about the pancreas cutting off the supply of blood from which the secretion was ob- tained, and so putting a stop to it. He then put a ligature round the duct at the point of its immergence into the intestine, but again failed in getting any secretion, which he attributes to its escape by the small ducts wounded in exposing the larger one. His third attempt consisted in binding together two pieces of wood, compressing the intestine over the point of entrance of the duct so as to close it. This time he was successful : the duct was distended with a clear and limpid fluid, but he could not obtain it in sufficient quantity to subject it to any ex- amination. With the view of obtaining sonic notable quantity, he instituted a fourth ex- periment by making a longitudinal incision into the duodenum, and inserting into the orifice of the duct the narrow mouth of a little flask ; but again he failed, from the air included in the flask barring the entrance of the secretion. To obviate this, in his fifth experiment he perforated the upper part of the flask with a little hole, and this time he succeeded, in the space of five hours, in get- ting the flask more than half full. But the secretion obtained was bitter in taste and yellow in colour, and, attributing this to a certain admixture of bile from the uncleansed intestine, he improvised the following in- genious apparatus to obviate that source of fallacy. He took a long-necked flask, with a hole bored in the upper part of its belly, and around the neck of this flask he fastened a cord furnished with rings, by means of which it could be firmly fastened to the intestine ; a quill of a wild duck, cut so as to form a little slender tube, was then fixed into the neck of the flask, and made to fit tightly by pasted paper being rolled round it. Into the smaller extremity of this quill tube was fixed a plug made of some soft wood fitting sufficiently tight not to be forced in by the pressure of the soft parts it would come in contact with, but sufficiently easy to be withdrawn by a string fastened to it, and which passed through the quill into the flask and out of the flask through the little hole. The object of the plug was to prevent the in- testinal contents from blocking up the quill and so obstructing the flow of the pancreatic secre- tion. Then (" sublato ejulatu vicinis molesto, duarum laryngis cartilaginum particulas ex- scindendo," as he says of the poor dog with great simplicity and coolness) the abdominal cavity is laid open, an incision is made into the duodenum, the quill, closed with the little plug, inserted, the flask sewed to the intestine by means of the rings, the parietes sewed up so as to allow the protrusion of the flask, the plug withdrawn by the string, and the flask covered so as to prevent the entry of any foreign matter through the little hole. To PANCREAS. 101 obviate the escape of the secretion through a second pancreatic duct, which, he says, he found very common, he closed this second orifice by an ingenious method of compres- sion. With this apparatus he succeeded in getting a free supply of pancreatic fluid, as clear as spring water, but slightly viscid, and van ing in taste, from salt to acid, rough, acidulo-saline, or insipid. De Graaf's memoir is well worth reading, and is, considering the time in which it was written, and in spite of the necessary admixture of a good deal of mediaeval physiology, a model of sagacious forethought and patient research. He insists strongly on the acidity of the fluid, not only in the dog, but in man, and affirms that he and many others found it to possess an acid taste in a man who had been suddenly killed, and whose body was still warm. But it is necessary to bear in mind his coarse and superficial means of examination, and the bias with which he undertook his researches from his strong attachment to both the physio- logical and pathological views of Sylvius. Schuyl*, also a disciple of Sylvius, adopted a process analogous to that of De Graaf, and succeeded in obtaining a quantity of the secretion, amounting to two or three ounces, in three hours ; he pretends that what he collected had an acid taste, and affirms, more- over, that it coagulated milk. The researches of Wepferf, Pechlin J, Brunner$, and Bohn j| did not confirm the assertions of De Graaf and Schuyl. These observers found the pancreatic secretion turbid, whitish, not acid, but having a taste slightly saline, like that of lymph. Succeeding experimenters agreed no better with regard to the qualities of this liquid. Viridetlf said that he found it acid in most animals, and pretended that it sen- sibly reddened litmus. Hduermann**, on the contrary, denied that it had this effect. Fordyce f f found that of the dog to be co- lourless, watery, and salt in taste, and affirmed it to be composed of water, mucus, soda and phosphorus. Meyer JJ has examined the pan- creatic juice in a cat, which he found in the vesicular reservoir which is sometimes met with in that animal. It appeared transparent, viscid, and had an alkaline taste ; it coloured the mallow dye red, and red litmus paper blue. Meyer says further that he found in it albumen, chlorides of sodium and ammonia, and a peculiar matter giving a violet pre- cipitate, with chloride of tin. Lastly, Ma- genclie found §§ the pancreatic juice in a dog to be yellowish, inodorous, and with a saline taste. He adds that the liquid is alkaline, * Tractatus pro Veteri Medicina. Leyde. 1670. t De Cicuta Aquatica, p. 200. j De Purgantium Medic. Facult. Leyde. 1672. § Experiment Xova circa Pancreas. " Amst. 1C83. J| Circulus Anatomico-physiologicus. Leipsig, De Prima Coctione, p. 266. '* Physiologic, th. iii. p. 807. ft Versuche Uber das Verdauungsgeschaft, Leip- sig, 1793. JJ Journ. compl. et Diet, du Sc. Me'd. t.iii. p. 283. §§ Pre'cis Ele'mentaire de Physiologie, t, ii. p. 267. that it coagulates with heat, and that in birds it is altogether albuminous ; at least, that, ex- posed to heat, it coagulates like albumen. With such various opinions as to the qua- lities of the secretion, it is not surprising that the views of its function should have been discrepant, and accordingly we find that many hypotheses, often far-fetched and extra- vagant, were adopted to explain the part which the pancreatic fluid played in digestion. Some thought that it had for its destination the separation of the chyle from the excre- ments ; others, that it served to temper the acridity of the bile; others, again, thought that it diluted the chyme, or that it dissolved that portion of the food which had not been digested in the stomach ; that it contributed to its assimilation, &c. Haller, after ex- hausting himself with conjectures, can only say, " Plura possunt esse officia liquoris non- dum satis noti ;" and Magendie, fifty years later, admits that it is impossible to say what the role of the pancreatic fluid may be. Such, then, were the opinions expressed, or rather the ignorance confessed on this subject, when in 1823 the Academy of Paris proposed the function of digestion as the subject of a prize dissertation, and two of the essays sent in, which were considered by the Academy worthy of honourable mention — the one by Professors Tiedemann and Gmelin, and the other by MM. Lenret and Lassaigne — threw so much additional light on the subject, and furnished results which so long constituted the staple of our certain knowledge of the function of the pancreas, and so much of which still remains unquestioned, that they deserve special consideration. Lenret and Lassaigne, thinking that the failures of recent experimenters to get any of the secretion arose from the smallness of the duct in the animals employed, selected the horse, and succeeded in obtaining three ounces in half an hour of a limpid liquid, with a slightly salt taste, alkaline reaction, specific gravity of 1-0026, and containing '9 per cent, of solid matter. Sulphuric, nitric, and hydrochloric acid slightly troubled it, and alcohol formed a more abundant cloud, precipitated after a time in white "flocculi ; an aqueous solution of chlorine determined a light flocculent preci- pitate ; infusion of gall-nuts occasioned a yellowish deposit ; lastly, nitrate of silver and protonitrate of mercury showed the existence of chlorides, and oxalate of ammonia that of lime. On treating the solid residuum with alcohol and evaporating, it yielded a transpa- rent viscid matter, with a salt and sharp taste, the non-crystallizable portion of which con- sisted of an azotised substance precipitable by many metallic salts and solution of gall-nuts. That portion of the residuum of the pan- creatic juice which had been exhausted by the alcohol was then heated with distilled water, when this latter showed on evaporation a certain viscosity, indicating the solution of an animal principle in it. The result of the en- tire qualitative analyses, the further details of which I need not give, was as follows : — ii 3 102 PANCREAS. Water - Animal matter soluble in alcohol Animal matter soluble in water Traces of albumen Mucus - Free soda Chloride of sodium Chloride of potassium Phosphate of lime 99-1 00*9 Oxide of iron -J - a trace 100-0 " Not content," say these observers, " with this first experiment, we undertook a second with the same success *, and the results fur- nished by analyses were absolutely the same : from which we infer that the pancreatic juice possesses a perfect analogy with the saliva both of man and the horse, these two liquids containing absolutely the same fixed principles, nitrogenous and saline, and almost exactly the same quantity of water.-f- The attempts of these authors to obtain the pancreatic secre- tion of a dog, after the manner of De Graaf, were all unsuccessful; ten times they tried, and as often failed ; a few drops were all they could procure. Their data, therefore, are all taken from the secretion as they found it in the horse. Tiedemann and Gmelin J obtained the pan- creatic fluid from the dog, the sheep, and the horse — that is, from one carnivorous and two herbivorous animals ; and their results present the most striking discrepancies with those of the contemporaneous experiments of Lenret and Lassaigne. In the dog this fluid, which was obtained abundantly, was limpid, with a faint blueish, opalescent cast, and a mucilaginous feeling like the white of egg diluted with water, a slight but sensibly saline taste, the first por- tion faintly acid, the portion last secreted slightly alkaline, and so abundantly albumi- nous as to be rendered semi-solid by heat nitric acid, &c. A hundred parts of the se- cretion contained — Solids - - 8-72 Water - - 91-28 100-00 100 parts of solid matter contained Organic substances, osmazome with a peculiar animal matter coloured red by chlorine (with alkaline acetates and chlorides) - - 44-32 Caseous substance, possibly with another animal substance, solu- ble in water, but not in alcohol (with salts of soda) _ lg'44 Albumen, with a small quantity of salts - ... 42-83 105-59 Exceeding - 5-59 * They do not say the quantity they obtained this time. f Loc. cit. p. 106. | Recherches Experimentales Physiologiques et Chimiques sur la Digestion. Jourdan's transla- tion, p. 24. et seq. The secretion of the sheep was acid, and, like the other, ropy between the fingers like white of egg, and limpid ; it was perfectly so- lidified by heat, and contained — Solids (desiccated) 5-19 Water - - 94 81 100-00 Of these solids nearly 60 per cent, were albumen. The secretion in the horse resem- bled in all its reactions that of the sheep, except that the albumen was not so abundant. The summary conclusions at which these authors arrive, are that the pancreatic fluid contains — 1 . In solids, in the dog 8*72, in the sheep 5 per cent. 2. The solids consist of — a. A large amount of albumen, about half of the dry residuum. b. Osmazome. c. A substance reddened by chlorine, found only in the dog. d. A caseous substance, probably allied to salivary matter. e. A small amount of free acid, probably acetic, present in all these specimens. It is worthy of remark, that that por- tion of the pancreatic fluid which was secreted last was slightly alkaline : this change probably depended on the enfeeblement of the nervous influence resulting from the operation. /. The ash consisted of alkaline carbo- nate, chloride, phosphate, and sulphate, and carbonate and phosphate of lime. g. The alkaline sulpho-cyanide is not met with in the pancreatic secretion. h. The alkali consists of a large quantity of potash, and a very small portion of soda salts. If we compare the composition of the pan- creatic secretion in the dog and the sheep with that of the saliva, we find the following differences : — 1. The solid residue of the saliva does not equal half that of the pancreas. 2. The saliva contains mucus and a peculiar animal (salivary') matter. If it contains al- buminous or caseous matter, these subtances are, in every case, in very small quantity. On the contrary, the pancreatic fluid contains an abundance of albumen and caseous matter, but not a trace of mucus, and true salivary matter, if it exists, is in very small quantity. 3. The saliva is neutral, or contains a little alkaline carbonate. The pancreatic secretion contains a little free acid. 4. The saliva contains sulpho-cyanide of potassium ; in the pancreatic fluid there is none. 5. The other salts are nearly the same. 6. It results, therefore, that those physio- logists who think the pancreatic secretion identical with saliva are in error. There is, then, an entire discrepancy be- tween these two authorities with regard to the pancreatic secretion — its physical quali- ties, reaction, amount of solids, chemical con- stitution, the conclusions they infer, &c. PANCREAS. 103 Very lately this subject has been taken up by several able physiologists, and Bernard*, Frcrichs -J-, and Bidder and Schmidt J, have given to the world the results of careful and elaborate researches both into the physical and chemical characters of the fluid and its physiological action. I shall describe first the observations of these inquirers on the qualities of the secretion, and, afterwards and sepa- rately, their views of its physiological office. It is very remarkable, that the differences in the accounts given by these recent investi- gators are vcr}- closely analogous to those ex- isting between the results of the researches above described. They all agree, however, as to the invariable alkalinity of the secretion, the absence of sulpho-cyanides, the existence of a specific nitrogenous principle, and, in general, to its possession of strong differen- tial characters when compared with saliva. According to Bernard, the pancreatic secre- tion obtained artificially during the life of the animal is of two very distinct kinds, which he characterizes as normal and morbid; the for- ner obtained when the experiment is made under favourable circumstances, before inflam- mation has attacked the pancreas, or which is collected from a dog possessing a permanent pancreatic fistula; the latter alwajs secreted in great abundance when the symptoms of in- flammatory reaction appear in the pancreas and in the wound in the abdomen. The normal secretion, which, adopting Ber- nard's view, is of course the secretion, he de- scribes as a colourless, limpid, viscid, ropy fluid, without any characteristic odour, and having a saline taste very like that of the serum of the blood. It is constantly alkaline. Exposed to heat, it is converted into a solid white mass ; the coagulation is as entire and complete as that of white of egg, the whole becomes solid, not a drop of free liquid re- maining. The other reagents of albumen equally precipitate it. The alkalies produce no precipitate, and redissolve the organic matter when it has been previously coagulated by heat, alcohol, or the mineral acids. But, although exhibiting the same reactions, Ber- nard believes that this nitrogenous principle is essentially distinct from albumen, not only in a physiological point of view, but in its in- herent nature; and, as a proof of this, he cites the fact, that when it has been coagulated by alcohol and dried, it is easily and entirely redissolved in water, whilst albumen, similarly treated, is not dissolved to any appreciable extent. <) These characteristics of the fluid, which are given from the dog, Bernard says obtain equally in rabbits, horses, and birds. The n-orbid pancreatic fluid, which is alone thrown out when the experiment is tardily or * Arch. Gen. de MeU, 4th Ser. torn. 19. p. 68—86. f Wagner's Hanchvorterbuch der Physiol. j Die Verdauunggeschaft und der Stoffwechsel, Leipsig, 1852. § Bernard believes this to be the active matter of the secretion, as it imparts to the water the pe- culiar viscosity aud physiological properties of the pancreatic fluid. roughly performed, and uhich always succeeds to the other when the experiment is happy, is watery, without any viscosity, has a saline and nauseous taste, is of very low specific gravity, and gives hardly any precipitate on the appli- cation of heat, nitric acid, &c. It is poured out very abundantly : Bernard collected from a dog more than half an ounce in an hour, whereas of the normal he found 31 grains a maximum. The normal is not transformed into the morbid secretion suddenly, but gra- dually, losing, as it becomes more "and more watery, its physiological properties, of which at last it is quite destitute. This observation of Bernard's is very important, as showing the facility and extent to which the fluid may be changed, and doubtless it goes some way to explain the discrepancies of the ac- counts which different observers have ren- dered, but it is not entirely sufficient for this, as, in some hands, a watery fluid with but little albuminous matter and of very low specific gravity seems to have been obtained at once, even under circumstances the most favour- able. Frerichs, who has made a most complete analysis of this fluid *, and with whose ac- count Lehiuann-{- agrees, describes it as co- lourless, clear, very slightly tenacious, without taste or smell, of alkaline reaction and a spe- cific gravity as low as 1-008 to P009 ; heat, alcohol, and acid, produce but a slight turbi- dity; of solid constituents he found it contain but 1*36 per cent, in the ass, and 1*62 in the dog. Schmidt's account is something interme- diate between the other two; he describes the fluid as ropy and viscid, and as being coagu- lated by heat into a milky mass, from which white flocculi subside, leaving above a clear, strongly alkaline fluid. He agrees with Bernard in the solubility by water of the precipitated and dried albuminous matter ; he states the specific gravity of the fluid at P03I, and the quantity of solid constituents at 9'924 per cent.; in one case the amount of solids reached 11*56 per cent. The following are the quantitative analyses of Frerichs and Schmidt : — Pancreatic juice of ass (Frerichs). Water - ... 986'40 Solid residue - - 13'60 Fat - Alcohol extract Water extract Soluble salts Insoluble salts 026 0-15 3-09 8-90 P20 Pancreatic juice of dog (Schmidt). Water- - - - 900'76 Solid residue - - 99-24 Organic matter Inorganic 90-J8 8-86 * Op. cit. p. 842—849. t Physiol. Chem. (translated by Day), p. 112. et seq. H 4 104 PANCREAS. The exact nature of Frerichs' water extract — Schmidt's organic matter — is not deter- mined ; it is a substance resembliny albumen or casein, but not identical with albuminate of soda, with casein, or with ptyalin. It coagu- lates only imperfectly when heated (probably from its containing an alkali), is precipitated by acetic acid, but slowly redissolved in an excess, especially if heated ; it is precipitated by nitric acid and by alcohol; on the addition of chlorine- water it separates in grayish flakes. It is to this substance that the pancreatic fluid owes its principal chemical and physiological properties. Bernard found a considerable quantity, and Frerichs a smaller amount ('026 per cent ) of a buffer-like fat. The pancreatic secretion is peculiarly prone to putrefactive change. Bernard found that when exposed to a low temperature, it might be kept for many days, and that by the reduction of the temperature the viscidity was increased, approaching a jelly-like firmness. If, on the other hand, it was kept at a temperature of 40° to 45° centigrade (about 105° Fahr.), it became rapidly modified, and in the lapse of a few hours quite altered, giving out a nauseous odour, presenting a cloudy deposit, and losing its property of coagulation by heat. In the heat of summer and in stormy weather, this change takes place almost instantaneously, so that great care is necessary in maintaining at a low temperature both the pancreatic fluid and the animal furnishing it, lest the alteration should take place whilst it is still in the vessel in which it is being collected. Frerichs found that after exposure to the air for a few hours it developed a distinct odour of putrefaction. Bernard observed that the deposit that was produced at the moment of the alteration of the fluid, had sometimes a peculiar soft, silky appearance, and he always found in that case, on examining it by the microscope, a large quantity of acicular crystals, having the cha- racters of crystals of margarine or margaric acid. The secretion is not constant, but intermit- tent, and is entirely regulated by the process and stages of digestion ; all observers agree in this. Bernard killed three dogs in three dif- ferent conditions with regard to the function of digestion — one just after a meal, as diges- tion was just commencing ; another four hours after a meal, when digestion was at its height ; and a third after a twenty-four hours' fast. In the first, the tissue of the pancreas was slightly turgid with blood, and the secretion the most abundant, and this he has always found to be the case ; he collected upwards of two grammes an hour ; in the second, the pancreas was highly turgid — " gonfle de sang, et comme erectile," and the amount secreted less than a gramme an hour ; in the third it was white, exsanguine, the duct empty and collapsed, and the amount secreted in 'many hours hardly enough to moisten the inside of the little reservoir adapted for its reception. The information respecting the absolute quantitative relations of the secretion is very defective. We have seen that Lenret and Lassaigne obtained three ounces from the horse in half an hour, and Bernard from the dog thirty-one grains an hour; Frerichs col- lected three hundred and eighty grains from an ass in three quarters of an hour, and forty- five from a hound in twenty-five minutes ; but these statements, as well as 'those of Colin *, become valueless from the fact that the ani- mals experimented on were not weighed. The most reliable estimate is that of Bidder and Schmidt ; they say a dog yields a grain and a half per hour for every two Ibs. of weight ; therefore an adult man weighing about 140 Ibs., would secrete in twenty-four hours nearly five ounces of pancreatic juice, containing 225 grains of solid residue. But it is doubtful whether any safe data as to quantity are fur- nished, or can be furnished, by any experi- ments made by measuring the amount pro- cured artificially from the living animal ; the abnormal condition of the gland produced by the experiment must be such, and the conse- quent disturbance of the secretion so great, as to throw doubt on the most careful and exact estimates. The case in which the quantity seems most likely to be normal is that in which the secretion is obtained, as in some of Ber- nard's experiments, from a permanent fistulous opening. All observers confirm Bernard's statement as to the exsanguine and passive condition of the gland in animals fasting. The natural stimulus of the secretion is, no doubt, the digestive process going on in neighbouring organs, producing, through the medium of the sympathetic nervous connec- tions, a vascular engorgement of the pancreas and an exalted nutrition of its secreting agents. Possibly the pressure from a dis- tended stomach may have something to do with it ; and there is reason to think that the presence of food in the duodenum is both a stimulus to the secretion and to its discharge ; for on the application of chemical and me- chanical stimuli to the inner surface of the duodenum near the orifice of the duct, the amount discharged is sensibly increased. Possibly food of one nature in the duodenum may be a more exciting stimulus to the se- cretion than another. Whether this is so, whether the amount secreted would be ex- cited more by an animal than a vegetable food, whether it bears the same relation to the volume of the gland in Carnivora and Herbivora, or whether the volume of the gland is always a direct measure of the amount secreted, are questions upon which, as yet, our information is very defective. They are, however, not unimportant questions ; for there is every reason to believe that the quantity secreted is always in proportion to the exigencies of the digestive process, and their solution might therefore throw some light upon the function of the secretion. There can be no doubt that muscular move- ment and pressure facilitate the discharge of the fluid, as most observers, from De Graaf * Comptcs Rcndus, vol. xxxi. p. 374., and vol. xxxii. p. 85. PANCREAS. 105 downwards, have remarked that the act of in- spiration, and violent respiratory or struggling efforts, always increase the rapidity of its flow. The following is a tabular view of the state- ments of different observers of the principal characters of the pancreatic secretion : I Ticdeinann and Gmelin. Lenret and Lassaigne. Bernard. Frerichs. Bidder and Schmidt. General Physical Qualities. Limpid with a blue- white cast, like white of egg diluted with water, slight, but sensibly saline taste. Limpid with a slightly salt taste. Colourless, limpid, viscous and stringy ; odourless ; taste sa- line. Colourless, clear, with its long diameter half an inch in extent, and directed transversely. To it is articulated the base of the coccyx. The anterior or pelvic surface is smooth and directed forwards and downwards, form- ing the posterior wall of the true pelvis. It is widest above, opposite the lateral masses of the base (e). A little below this point it is about three-fourths of an inch nar- rower (A). It then widens again to the extent of nearly half an inch (/ ), and then gradually tapers to the apex. It is consider- ably arched from side to side, especially at its superior part, where it has a transverse cur- vature, varying from half to three quarters of an inch in central altitude. Longitudinally, also, this surface is curved to a still greater degree, and with greater variations, upon the comparative extent of which, in male and female, anatomists are much disagreed. On each side of the median line are four holes, the anterior sacral foramina, separated from each other by three rounded transverse processes of bone about half an inch wide (4), and placed at equal distances of rather more than half an inch from the median line. The two upper holes are of equal size, and much larger than the two lower. Each is con- nected to its fellow on the opposite side by four raised transverse lines (5), which mark the foetal separation of this bone into five ver- tebrae ; and extending outwards and down- wards from each hole is a groove continued obliquely downwards to the borders of the bone (6). Below the last sacral hole, on each side, is a shallow notch, in the outline of the bone (c, c'), which is transformed into a foramen by the attachment of the upper transverse tubercles of the coccyx. There are many openings for nutritive arteries in this surface, directed generally towards the centre of the bone. The posterior surface (./%. B) is rough for muscular attachments, and directed upwards and backwards. It is narrower than the op- posing parts of the anterior at the upper part of the bone generally, by rather more than half an inch. According to Mr. Ward, a transverse section of the sacrum, an inch below the base (at the second sacral ver- tebra), shows that in this place the posterior surface is wider than the anterior by three sixteenths of an inch, so that the sacral wedge is here reversed in obliquity, which he con- siders of importance in resisting anterior dislocation of the sacrum. Above this point, the anterior surface is three sixteenths of an inch wider, and below, it resumes its supe- riority in width by four sixteenths. In some cases the back and front are of equal width ; in others the anterior diameter exceeds the posterior throughout. Its general curvatures are convex, following the concavities of the anterior surface. In the median line are four spinous processes (2), the first of which has been described with the base, connected by a sharp vertical ridge of bone, and corresponding to the four upper PELVIS. 119 pieces or vertebrae of which the sacrum is com- The last of these, and sometimes the two lower posed, the whole being called the sacral crest, are divided by a notch (10), which opens u Fig. 78. A, anterior surface and lose of sacrum ; B, lateral and posterior view of the same bone; c, anterior surface and base of coccyx. the sacral canal at its inferior termination, where it is much compressed antero-poste- riorly. On each side of the sacral crest is a narrow vertical groove, corresponding to the vertebral laminae, and bounded externally by four rough tubercles, the articular (4), the last of which are confounded with the bifurcated inferior spine, and project downwards in two inferior sacral horns (5), which are smoothed into facets posteriorly, to articulate with the coccyx. They correspond to the articular processes of the vertebras. Immediately ex- ternal to them, and on the same level, are the four posterior sacral foramina (6), of irregular size, but much smaller than the anterior, to which they are opposed in situation. The broad surfaces of bone between them present another continuous shallow vertical groove, external to which are three or four tubercles, the transverse (7), arranged vertically parallel with the holes, and corresponding to the tips of the transverse processes of the vertebrae. The highest of these are sometimes smoothed into a facet externally (8), by impinging upon the iliac tuberosity, and the fourth (9) is al- ways the largest and most prominent for the attachment of the superficial posterior sacro- iliac ligaments. Close to the lateral boun- dary, opposite the two upper transverse tubercles, are two very rough, digital impres- sions for the insertion of powerful posterior sacro-iliac ligaments. The latei-al surfaces of the sacrum (fig. B) are broad above, and taper gradually downwards. When opposite the two last sacral vertebrae, they become narrow borders (rf). Above, at the three upper vertebrae, they oppose the inner surface of the ilia — below, they form the inner margin of the great sciatic notch. At the upper broader portion these surfaces are bevelled off pos- teriorly, the posterior surface of the bone being at this part narrower than the anterior, and its plane being less distinctly different from that of the lateral surfaces. It is over- hung by the tuberosities of the ilia. Close to the upper and anterior margins, occupying the two anterior thirds of the lateral aspect of the base, and extending as far downwards as the third sacral vertebra, at which point the anterior surface of the sacrum becomes, as before mentioned, broader, is a large, angular articular surface, the iliac or auricular (e), de- pressed along the centre, and exactly cor- responding to the shape and irregular surface of the opposing articular surface of the ilium with which this bone is here jointed. The salient angle corresponds to the rounded an- terior border'of the lateral masses of the base, and the retiring angle, to the digital depres- sion at the edge of the posterior surface. Two prominent portions may be particularly observed on this articular facet, one at the salient angle (e) on the first sacral vertebra, and another at the termination of the in- ferior limb (f) on the third sacral vertebra. They correspond to similar depressions in the opposed ilium. The sacrum is traversed longitudinally down the middle, but nearer to the posterior than to the anterior surface, by the inferior termination of the spinal canal, which com- municates with the anterior and posterior sacral foramina, the terminal nerves of the cauda equina being contained and distributed within it. Internal structure of the sacrum. — The in- terior is composed of a closely reticulated mass of spongy bone, enclosed in thin, laminated surfaces. For its size, it is the lightest bone in the body, from being made up chiefly of cancellous structure. The laminae, spines, and articular processes are, however, chiefly composed of dense bone. 120 PELVIS. The COCCYX (fig. c), the hitckle, or whistle bone (named from its supposed resemblance to a cuckoo's bill, from KOKKV£, Or.; Os coccygu, Lat. ; rOs coccyx, Fr. ; das Steissbein, or Schwanzbein, Germ.), is an appendage to the apex of the sacrum, and terminates the spinal column inferiorly. It forms the posterior boundary of the lower part of the cavity, and inferior outlet of the pelvis, assisting to complete its walls, to sustain its contents, and to attach some muscles of the leg and perineum. Its position is oblique from behind, forwards and downwards, but being normally movable on the sacrum, it yields to pressure in both ways. It is usually composed of four, rarely five pieces or tu- bercles, which are generally, but not always, soldered to each other, and diminished in size and completeness downwards. When in one piece, it presents a tapering, elongated, knob- bed appearance with an anterior and posterior surface, two lateral borders, and a base and apex. The base presents a plane, oval, arti- cular surface (#), corresponding to the apex of the sacrum, with which it is articulated, and sometimes ankylosed. Behind this, on each side, projects upwards and backwards a cornuated process (A), tipped with an ellip- tical articular facet, directed upwards and forwards, to articulate with the inferior sacral horns. Below these, the borders commence, presenting three alternate notches (), similar in character to the last, but thinner and more feeble, passing from the first three bones of the sacrum to the superior border of the iliac notch. The former of these assist to prevent downward and backward displacement, and the latter upward and backward displacement ; the position of the former being more anterior than superior, and the position of the latter more inferior than anterior in the proper position of the pelvis. By far the most powerful of the ligaments of this articulation, and that which must be con- sidered as the chief means of supporting the great downward pressure at this joint, are the posterior sacro -iliac ligaments. These are di- vided into deep and superficial layers of fibres. The deep layer (fig. 89. page 144. e) passes from a well-marked prominence on the anterior surface of the iliac tuberosity, downwards and inwards, to the superior lateral part of the pos- terior surface of the sacrum, principally to the two upper pieces, external to the foramina ; the fibres spreading out in interlacing bundles to- wards the broader surface of implantation on the sacrum, becoming longer as they become more superficial, and leaving meshes for the interposition of masses of loose fat, and the passage of numerous small veins. The erector spinae muscles arise from the surface of this ligament, and cover it. To obtain a good view of these fibres, a transverse section along the brim of the true pelvis should be carried backward through the sacrum, as shown in the figures. This will show the manner in which the tuberosities of the ilium hang over the sacrum, suspended, as it were, between them by these ligaments. It will be more par- ticularly explained when treating on the me- chanics of the pelvis. The superficial posterior sacro'iliac ligament (Jig. 8 1 ., next page, a) has been termed oblique, from the direction of its fibres ; or long, from the extent of them. It is attached above to the posterior superior spine of the ilium, and passes downwards and ob- liquely a little inwards to be implanted jnto the fourth transverse tubercle of the sacrum ex- ternal to the hole. To the sides of this liga- ment, which is almost subcutaneous, are at- tached the fascia lumborum and great gluteus muscle. This ligament is described by Cru- veilhier to be attached to the third sacral vertebra. In all the cases I have seen, it is attached to the fourth transverse tubercle, which is the most prominent tubercular pro- jection in the dried bone. Bichat erroneously calls it " sacro-spinous." Attached to the same sacral tubercle, and passing horizontally outwards to be im- planted into the posterior surface of the in- ferior posterior spine of the ilium, a point exactly corresponding to the termination of the horizontal limb of the sacro-iliac articular surface, is another well-marked ligament (fig. 81. b), which, being separated by a dis- tinct cellular interval from the deep ligaments and distinguished by the more deeply seated position and horizontal direction of its fibres from the oblique ligament (a), and from the the name of the inferior or short^ superficial posterior sacro-iliac Sgament. This ligament has been hitherto apparently confounded with the great sacro-sciatic, which is attached to its lower border by a thin fibrous extension. fts. 81. 124 PELVIS. great sacro-sciatic ligament (r), I think merits pelvis postictnn magnum, fg. 81. c) is attached - - • ~ • ' • —*--~i behind, to the posterior inferior spine ot the ilium by a membranous expansion (e); to the superficial posterior sacro-iliac ligaments with which its fibres are blended; to the posterior surface and borders of the two last pieces of the sacrum ; and to the posterior sacro- coccy- gean ligament and borders of the two or three upper coccygeal bones. From this broad at- tachment its fibres pass downwards, forwards, and outwards to be implanted into the whole length of the raised inner border of the great tuberosity of the ischium. The fibres of this ligament are arranged in fasciculi, which cross each other in an X-like manner, so as to present, at the extremities, an expanded appearance, and in the centre a thick con- tracted rounded outline. The fibres which are placed superiorly in one extremity of insertion cross at the contracted part to become inferior at the other extremity, while those which are internal cross in the opposite direction to become external. Its superior border, consequently, is directed outwards and forwards, and its inferior border inwards, and both present a curvilinear outline. At its insertion into the sciatic tuberosity, the fibres of the lower border present a falciform margin having the concavity directed upwards along the inner edge of the tuberosity, where it is united to the fascia covering the obturator in- ternus muscle. Its superficial or external fibres are continued over the tuberosity in- feriorly into the tendons of the biceps flexor cruris, and semi-tendinosus muscles. Near the posterior extremity, this ligament is almost invariably perforated by a small hole, through which passes the coccygeal branch of the ischiadic artery. To the whole length of its external or posterior surface is attached the great glutens muscle, which causes it when dissected to be very rough and flocculent. At the posterior half of its inner surface it is blended intimately with the lesser sacro-sciatic ligament, anterior to which it is smooth, and forms part of the boundary of the ischio- rectal fossa. The lesser or internal sacro-sciatic ligament (ligamentum pelvis posticum parvum, Jig. 81. d) lies internal to the last, in common with which it is attached posteriorly to the side of the two last pieces of the sacrum and of the two upper pieces of the coccyx. At its an- terior extremity it is contracted into a pointed insertion into the spine of the ischium. The direction of this ligament is horizontally for- wards and outwards, and its shape is triangular, so that its anterior contracted portion diverges from the great sacro-sciatic ligament, leaving a triangular opening between them through which pass the obturator muscle out of, am' the pudic vessels and nerves into the pelvis This ligament, thus passing from the sacrum across to the ischium, converts the sacro- sciatic notch into a triangular or oval foramen through which pass the pyramidalis muscle, the gluteal, ischiadic and pudic vessels, and the superior gluteal and great and lesser sciatic and pudic nerves out of the pelvis. With its Posterior view of the ligaments of the pelvis. a, oblique posterior sacro-iliac ligament ; b, infe- rior posterior superficial sacro-iliac ligament; c, great sacro-sciatic ligament ; d, lesser sacro-sciatic ligament ; e, membranous expansion over the pyri- formis muscle. The ligaments which may be considered as accessory to this articulation are three in number — the ilio-lumbar ligament above, and the greater and lesser sacro-sciatic ligaments below. The ilio-lumbar ligament (fig. 80. c} is a triangular fascicular ligament, thickest at the edges, and passing from the tip of the last lumbar transverse process, to which its apex is attached, horizontally outwards, and a little backwards to the posterior fifth of the inner lip of the crest of the ilium, along which its fibres spread as far forward as the inner projecting point of the posterior curve. To the outer side and behind this ligament is attached the quadratus lumborum muscle with the tendon of the transversalis abdo- minis, and to its front the psoas magnus muscle. Meckel describes this ligament as sometimes reaching as high as the transverse process of the fourth lumbar vertebra. He also describes a second ligament lower than the preceding, but arising from the iliac crest a little behind it. They are called by him, respectively, the upper and lower anterior pelvic ligaments, the latter corresponding to the sacro-vertebral ligament before described. The great sacro-sciatic ligament (ligamentum PELVIS. 125 anterior or internal surface are blended the fibres of the ischio-coccygeus muscle, which exclude it from the ischio-rectal fossa, and render it rough when dissected. Soemmering describes the lower part of the powerful lumbar fascia as a ligament connect- ing the ilia to each other posteriorly and to the lower spines of the sacrum. This fascia does, doubtless, act powerfully in clasping the ilia upon the sacrum between them. He calls it the lateral sacro-iliac ligament, or the posterior lateral iliac ligament. The important part which these three ac- cessory ligaments play in the mechanism of the pelvis will be hereafter shown. The movements of the sacro-iliac joint are very limited indeed, its principal characteristic being compactness and strength, with just sufficient sliding motion downwards and back- wards to break the shock of concussion pass- ing from the lower extremities to the trunk. This is said by some to be increased in preg- nancy and by parturition. The pubic symphysis (fig. 80. 2) is an azygos joint uniting the innominate bones by their pubic portions in front. The osseous surfaces composing it are oval, with the long diameter directed downwards and backwards, and ge- nerally an inch and a half long, by three quarters broad. The planes of these sur- faces not being directly opposed to each other, leave a larger interval of separation in front than behind. This interval is filled by a fibro- cartilaginous disc, which is correspondingly thicker in front, where the fibrous components are so numerous and strong as to constitute almost an interosseous ligament, and pass from one bone to the other in an oblique and concentric direction. Towards the central and posterior part this disc is generally mainly cartilaginous in structure, and is often, in females, separated in the middle by a chink forming two smooth, plane, oval contiguous articular surfaces, of various dimensions, some- times irregularly laminar, at others with a de- licate investing membrane. In parturient wo- men these surfaces often extend over nearly the whole of the articulation, and are well marked in a figure given by Dr. Hunter, in the second volume of Medical Observations and Inquiries. In males, this separation is seldom present. The whole of the disc may, however, by maceration, generally be separated into two plates {fig. 82. a, a), of a denser and more cartilaginous structure than the rest, each strongly adherent to the bone by mammil- liform fibrous processes (b), which pass into corresponding depressions in the osseous sur- faces (c), and are connected to each other on opposite sides, by continuation of their fibres, arranged in oblique and concentric layers, which interlace obliquely with each other, (rf) Dr. W. Hunter remarks, with Sandifort and Albinos, that the two cartilaginous plates (a,ff), covering the opposed surfaces of theossa pubis, are usually connected by a structure rather liga- mentous than cartilaginous ; and in a memoir on the pubic symphysis, gives an engraving of this arrangement. In several instances I have seen the fibrous processes which connect the plates with the bone very well marked, leav- Ftg. 82. Symphysis pubis after maceration. a, cartilaginous plates of Dr. Hunter ; ft, mam- millary processes on their osseous surface ; c, cor- responding osseous depressions to receive them ; d, inter-laminar concentric nbro-cartilaginous tissue divided vertically in the centre. ing on the bone, after maceration, deep conical pits. The above figure was taken from a ma- cerated preparation of this joint. According to the observations of Tenon, these processes are directed into the bone downward and backward, as well as outward, and tend to prevent displacement of the cartilage in that direction. The inter-laminar fibro-cartuUigin- ous tissue is very elastic and yielding, swelling out on the cut surface when lateral pressure is made on the bone, somewhat in the manner of the intervertebral discs. It often evinces a tendency to split in a lamellar direction after maceration. Around the circumference the concentric fibres become much more numerous and strong, and are continued into the peri- pheral ligaments. These are an anterior, pos- terior, a superior, and an inferior ligament. The anterior pubic ligament (fig. 80. rf) is a thick layer, passing between the anterior sur- faces of the bones, strengthened by and blended with the oblique fibres of the aponeurosis of the external oblique muscle continued to the opposite pubic bone in front of the joint. The posterior pubic ligament is the most feeble. It is composed of transverse fibres, somewhat scattered, and is remarkable in being raised by the posterior border of the pubic fibro-car- tilage into a vertical ridge, in old persons often very evident to the touch. It gives attachment to the superior true ligaments of the bladder, and the anterior fibres of the levator ani muscle. The superior pubic ligament (e) is formed by a thick, smooth layer of fibres often raised by a central ridge like the posterior, passing between the crests of the pubes, the super- ficial fibres extending over the greater part of the crests, and giving origin to the recti ab- dominales and pyramidales abdominal muscles, and lineaalba. 126 PELVIS. The inferior or sub-pubic ligament, (Hga~ mentum arcuatum, f~) is the most powerful, passing from one descending ramus of the pubis to the other in an arched form. Its place of attachment to the pubis is often a well-marked surface, triangular, with the base upward, and half an inch in depth, cor- responding in this respect to the outline of the section of this ligament. This ligament and the anterior are the most intimately con- nected with the fibro-cartilage of the joint. It unites below with the two layers of the deep perineal fascia or triangular ligament, be- tween which it gives origin to the vertical compressors urethra, and forms the superior boundary of the pubic arch, the apex of which it rounds off and smoothens. The movements of the pubic symphysis are confined to a slightly yielding sliding motion giving elasticity to the resistance of the pelvic ring. The obturator or thyroid membrane (g) is a fascial aponeurosis rather than a ligament, which closes in the oval foramen of that name. It is composed of layers of fibres, intermin- gling in a circular direction, and generally congregated more in some places than others. These are attached to the rough narrow bor- der of the descending branch of the ischium externally, but at the internal half of its cir- cumference it is attached to the posterior sur- face of the ascending branch of the ischium and descending branch of the pubis, overlap- ping in this situation the borders of these bones posteriorly. Superiorly, it is inter- rupted by passing over from one edge of the sub-pubic notch to the other, so as to form the lower boundary of a foramen for the pas- sage of the obturator nerves and vessels. Opposite the cotyloid notch its fibres are continued into the capsular ligament invest- ing the hip joint. By its anterior surface, it gives attachment to the obturator external muscle, and, by its posterior surface, to the internal muscle of the same name. It is some- times deficient in one or more places. GENERAL APPEARANCE OF THE ARTICU- LATED PELVIS. — When the bones of the pelvis are articulated together, its whole ap- pearance is that of a section of a cylinder or bent tube, having an anterior, posterior, and two lateral, and a superior and inferior aspects. Its anterior aspect (fig. 80.) is bounded on each side by a line passing from the anterior superior iliac spine, along the anterior border of the cotyloid cavity to the ischiadic tube- rosity on each side. It presents the pubic symphysis directed downwards and forwards in the median line, and the obturator fora- mina directed forwards, outwards, and down- wards on each side. As first noticed by Ouvier, this oblique direction of the sym- phvsis pubis is peculiar to the human species, that of animals being parallel with the axis of the body. In addition to these parts, already described, are two large notches formed by the approximation of the inno- minate bones. Of these the superior one, which maybe called the ventral notch, is formed by the vertical and horizontal portions of the anterior border of the innominate bones on each side with the peculiarities before men- tioned in its description. In the natural posi- tion of the pelvis this notch exposes to the view most of the internal surfaces of the pelvis to be described from the superior aspect. The inferior notch is formed by the oblique ascent towards the symphysis pubis of the branches of the ischium and pubis, forming what is termed the sub-pubic arch. Its apex is limited by the arched sub-pubic ligament, and there, in the male, it is generally about an inch wide, and at the base, between the ischiadic tuberosities, about three inches wide. The edges of this arch are in both sexes projected forwards, more or less, so as to present an in- clined surface to the plane of the arch. This eversion as well as the measurements are, however, considerably greater in the female pelvis, hereafter to be considered. The lateral aspects of the pelvis present the anterior half of the external surface of the ilia above ; the cotyloid cavities directed outwards, -forward and downwards, in the middle ; and the descending branch and hinder part of the tuberosity of the ischia below, the latter being directed outwards and backwards. The posterior aspect presents the posterior surface of the sacrum and coccyx in the cen- tre, the most prominent point, in the erect position of the body, being the divided spine of the fourth sacral vertebra. On each side, next in succession, occur the overhanging and projecting tuberosities of the ilia, constituting two prominences next in importance, conceal- ing the sacro-iliac articulations, and caus- ing the lateral parts of the three upper sacral bones to appear as a deep groove on each side for the reception and origin of the powerful erector muscles of the back. Be- tween these points also the last lumbar ver- tebra appears sunk between the two iliac crests, so that its upper surface is on a level with their most elevated central portion. Below the sacrum, the coccyx projects downwards and forwards in a salient median point, which separates and completes the inner boundary of the sciatic notches on each side, converted into foramina by the greater and lesser sacro- sciatic ligaments. The distance of the edges of the sacrum and coccyx from the spines and tuberosities of the ischia, and consequently the size of the openings, is less in the male than in the female ; but the depth of the notches vertically is greater in the former. Above these are seen the posterior half of the external iliac surface, or external iliac fossa, surmounted by the rising crest. The superior aspect (fig. 80.) reveals to view the whole of the internal surface of the pelvis, which presents two well contrasted portions, divided by a rounded edge or border, of which the superior is wide, expanded, and deficient in front, and is called the large, or false pelvis ; and the inferior, narrower, more complete, and more compact, is called the small, or true pelvis; while the border which separates them PELVIS. 127 is commonly expressed as the brim, or su- perior outlet of the true pelvis. The false pelvis is formed laterally by the con- cave surface of the internal iliac fossae directed upwards, forwards, and inwards ; and poste- riorly by the lateral masses of the base of the sacrum, directed upwards and forwards. In the middle is also seen, in the articulated pelvis, the anterior surface of the body of the last lumbar vertebra, filling up, with the pelvi- lumbar ligaments, the notch otherwise left be- tween the ilia behind. The superior border of the false pelvis is formed by the ilio-lumbar ligaments (\\ hich exclude the iliac tuberosities), and the anterior three- fourths of the iliac crest, the most prominent point of which, in the proper position of the pelvis, is the centre of the posterior curve. It is terminated sud- denly, in front, by the anterior superior iliac spine, where the ventral notch commences: by the deficiency of osseous structure at this part. The brim of the pelvis is a heart-shaped opening, formed posteriorly by the body of the first sacral vertebra which overhangs the cavity of the true pelvis, so as to form a pro- jection called the promontory of the sacrum (i), corresponding to the indentation in the emble- matical heart-shape. On each side of this, the rounded arched anterior borders of the lateral masses of the sacral base continue the brim across the sacro-iliac joint, to the thick rounded ridge on the inner surface of the ilium, which is prolonged behind the ilio-pectineal eminence to the horizontal branch of the pubis where the brim becomes identified with the pectineal line. Finally, the brim is completed anteriorly by the shelving border of the body of the pubis, immediately behind the crest, and by the rounded superior part of the pubic symphysis. The part of the brim of the pelvis which is formed by the two portions of the innominate bone is sometimes called the linea ilio-pectinea, or, by some, the linea innominata. Sometimes the brim is called the inlet of the true pelvis. The cavity of the true pelvis is formed laterally by the plane sloping inner surfaces of the lower part of the ilia, opposite the cotyloid cavities, and of the descending branches of the ischia, the latter being termed by obstetricians the planes of the ischia ; in front, by the posterior surfaces of the branches and symphysis of the pubis, and by the as- cending branches of the ilia ; and behind, by the whole concave anterior surface of the sacrum and coccyx, the former being some- times called the hollow of the sacrum. From the oblique position of the pelvis, the posterior wall, which is the deepest, also reaches the highest, and the lateral walls the lowest ; the sub-pubic arch cutting out the anterior wall and leaving only the short symph\sis pubis to represent it. The interval between the sa- crum and ossa innominata behind, forming the sacro-sciatic notch, is completed and bounded by the sacro-sciatic ligaments, the inner sur- faces of which are seen in this view. The inner surface of the coccyx is also seen to have an aspect directed upwards and for- wards, and the spines of the ischia to project considerably inwards, so as to present two opposite points, the distance between which may sometimes be of great importance in parturition. This projection is much greater in the male than the female> and will be al- luded to in the relative measurements of the pelvis. The cavity of the pelvis contracts uniformly downwards at the sides by reason of the inclination of the innominate bones ; but, from the vertical curvature of the sacrum, the antero-posterior diameter is much greater in the middle than at the superior or inferior outlets, which are hence termed straits. The presence of the obturator foramina antero- laterally, and of the sacro-sciatic foramina postero-laterally, must also be remarked as constituting four openings, diagonally op- posed to each other, capable, from the yield- ing nature of the structures filling them, of enlarging these diameters under sufficient pressure The great projection, forwards, of the coccyx and lower end of the sacrum may be considered as compensated for by the de- ficiency of the anterior wall in the sub-pubic arch directly opposite to them, gradually widening downwards as they advance. Both the forward direction of the coccyx, and the width of the pubic arch, are peculiar to the human species, and have reference to the erect posture. The inferior aspect of the pelvis presents to view the inferior strait, or outlet of the true pelvis ; which, on account of its more limited extent than the superior outlet, reveals no- thing of the interior save the overhanging promontory of the sacrum. It is remarkable in presenting three bony prominences, viz., the two tuberosities of the ischia laterally, and the coccyx posterit rly, separated by three notches, placed opposite to each prominence respectively, viz., the sacro-sciatic, postero- lateraily, and the sub-pubic notch anteriorly. The sacro-sciatic notches being closed by the great sacro-sciatic ligament, the completely formed opening thus assumes a lozenge shape, of which the lower part of the pubic symphysis and the tip of the coccyx form the extremi- ties of the long diameter ; the tuberosities of the ischia those of the short diameter ; the oblique united rami of the ischia and pubes the antero-lateral, and the great sacro-sciatic ligaments the postero-lateral sides. Of these boundaries it is to be especially remarked, that the coccyx and those parts of the liga- ments which are attached to it, are not fixed like all the previously described boundaries of the pelvis, but movable, on the sacro- coccygeal articulation, and consequently, the diameters of this outlet dependent upon them, viz., the antero-posterior and the oblique or diagonal, are increased or diminished by the movements of this joint backwards or for- wards. The only fixed diameter of the in- ferior outlet of the pelvis is the transverse one between the ischial tuberosities. Of the prominent osseous points here seen, the lateral ischial tuberosities descend much lower than the symphysis pubis and coccyx, en ac- 128 PELVIS. count of the wavy outline and oblique direc- tion of the innominate bones. It is upon these tuberosities only, consequently, that the trunk rests in the sitting posture, and not upon a tripod formed by them and the coccyx, as has been erroneously supposed by some older writers. The boundaries of the inferior outlet, from the same cause, do not, like those of the superior, lie all in one plane or level, but are bent, as it were, at the ischial tuber- osities, into two planes ; an anterior, termin- ated by, and nearly in a line with, the symphysis pubis, looking downwards and a little for- wards ; and a posterior, terminated by and in- cluding the coccyx, directed downwards and backwards, parallel with the superior pelvic plane, but varying with the extension of the coccyx downwards. The plane of this outlet, however, is usually considered to be marked by a straight line joining the lower border of the symphysis pubis and the tip of the coccyx ; and its general direction to coincide with a line drawn perpendicular to this plane down- wards and backwards. Differences of the pelvis in the sexes. — Of all the bones in the human skeleton, those of the pelvis offer the most distinct characters between the male and female sex. In the female {fig. 83.), the bones are lighter, shorter, and broader, less evidently marked by tuberosities and indentations re- sulting from the attachments of the tendinous structures, and have in a less degree the peculiarities, before described, of the articu- lations, as well as those resulting from their peculiar mechanism. The iliac crest is less arched, and presents less distinctly the £-like curve, the iliac wings are thinner and more expanded, and the internal iliac fossce larger, mare shallow, and directed more anteriorly, and the iliac ridge extending between the cotyloid and sacro-iliac joints is less massy, less suddenly arched, and longer. The ischia do not converge so much towards the inferior outlet, and with the tuberosities are less massy, wider apart, and shorter, and the spines are less marked, and directed less inwards, and the transverse diameter of the inferior strait is greater. The ascending branches and the descending branches of the pnbes are thinner, narrower, and more oblique, turn their inner borders more forwards, and at the same time afford a more rounded expansion to the pubic arch, at the expense of the obturator foramina, which are thereby rendered smaller and more triangular in the female. The symphysis of the pubis is not so deep, and the fibre-cartilage is wider, thicker, and more vertical in position ; the united angles are more flattened posteriorly, and the horizontal branch is longer, thinner, and directed more transversely outwards, rendering the distance between the symphysis and the cotyloid cavity, and consequently the projection of the hips greater, and an increased transverse diameter of the brim. The sacrum is wider and less arched trans- versely, and its promontory does not so much overhang the pelvic cavity, and thus the su- perior outlet has less of the heart shape, being in females more properly termed oval. This difference of shape is also contributed to by the less lateral obliquity of the superior branch of the pubes. Whether the sacrum is less arched trans- versely in the female, I endeavoured to ascertain by observations taken from eighteen subjects, of which half were male and half female. A strip of lead ith of an inch thick was made to assume the form of the transverse curve of the sacrum, by being pressed across the anterior surface just below the promontory, and the breadth from one sacro-iliac joint to the other care- fully marked off. From this, a line was drawn on paper, following the curvature re- tained by the lead, the extremities of which line were joined by a straight line, forming a chord to the sacral arc. The distance of the centre of this chord from the centre of the sacral curve was then measured. In the nine males, the height of the arch thus obtained varied from six to nine lines ; in the nine females, five to nine lines, — the greatest num- ber of the males being seven lines, and the greatest number of the females being six lines. In the single case of the female where the measurement was nine lines, the subject was old. When we consider, that in the great majority of instances the breadth of the sacrum measured along the curve wras greater by ^ to ^ an inch in the female, these results will yield a still greater relative depth to the transverse sacral curve of the male. Besides this transverse arch, the vertical curvature of the sacrum is relatively much less in the female. This is more apparent in the direction of the three upper sacral pieces, which are generally little 'curved, and often almost plane in the female, while, in the male, the curve is most apparent in the centre and more uniformly distributed over the whole sacral surface. Upon this point, how- ever, much difference of opinion prevails amongst anatomists ; Meckel and Ward agree- ing with the opinion here enunciated, while Cloquet and Cruveilhier maintain that the curvature of the sacrum in the female is deeper and more regular. The experiments of Mr. Ward, however, correspond more entirely with my own observations on this point. Mr. Ward observes, in addition, that the male sacrum often approaches the form of the female, but the female rarely to that of the male. In old women, however, I have often seen a great vertical curvature of the sacrum. The coccyx is more moveable, more fre- quently in several jointed pieces, less pro- jected forwards, and less frequently ankylosed to the sacrum in the female. The sacro-sciatic notches in the female are wider and not so deep as in the male ; the dis- tance from the ischiadic spine and tuberosity to the sacrum and coccyx being greater, and the sacro-sciatic ligaments longer and more slender. The peculiarities above mentioned give to the female pelvis a wider, shallower, more PELVIS. 129 open, and less massy appearance than that of the male, and give rise to a still more im- portant distinction derived from the measure- ments from one point to another, and from the relative diameters of the cavity and out- lets of the pelvis. Another distinction will be presently found in the relative angles which the sacrum and whole pelvis form with the axis of the spinal column, and this again will influence the relative direction of the axes of the cavity and outlets. Fig. 83. Anterior view of the female pelvis, with lines of m eas urement. a b, conjugate diameter of brim; c d, diagonal ditto ; ef, transverse ditto ; g h, transverse diameter of inferior outlet. Tlie measurements of the pelvis. — The most evident distinctions between the adult pelves of the sexes are derived from their com- parative dimensions, and result from the im- portant bearing they have upon the me- chanism of parturition in the female. For this purpose, an average is taken from the measurements of many well-formed pelves, and one with the average results is adopted as the standard pelvis. The measurements referring to the width of the pelvis are commonly spoken of as the diameters of the pelvis. They are taken at the brim, in the cavity, and at the inferior outlet, and are usually an anterior-posterior or conjugate, two diagonal or oblique, and a transverse. At the brim of the pelvis, the antero-pos- terior or conjugate diameter is the distance between the upper part of the posterior sur- face of the symphysis pubis and the pro- montory of the sacrum (a, b, jig. 83.); the oblique, between the point of the brim nearest the pectineal eminence and the sacro-iliac joint of the opposite side (c, d) ; and the transverse diameter is the distance between the ilia at a point halfway between the sacro- iliac joint and pectineal eminence (e,f). In the cavity, the antero-posterior diameter extends between the centre of the pubic sym- physis, and the body of the third piece of the sacrum; while the oblique and transverse correspond to those of the upper outlet, on the same plane. At the inferior strait, the antero-posterior extends from the lower extremity of the Supp. symphysis pubis to the tip of the coccyx ; and the transverse, from the middle of the inner border of one ischiadic tuberosity to the other (g, //). An oblique diameter at the inferior outlet is not one commonly given by writers, although possessed of some import- ance in certain cases of deformity. In the table on the next page, there is the average of six measurements taken on the recent subject, before the shrinking of the ligaments, from the centre or junction of the ischio-pubic rami to the centre of the great sciatic liga- ment opposite. The antero-posterior diameter of this strait is capable of much increase by the mobility of the coccyx, which will also affect, in some measure, the oblique diameters, in an opposite degree, from the stretching of the great sciatic ligaments, a point which I think has scarcely been sufficiently noticed by accoucheurs. Besides these, the distances between many other points may be of great importance to the accoucheur. Such are those pointed out by Naegele, to be presently noticed ; the distances between the spines of the ischia, so much greater in the female ; and another, which I have not hitherto seen definitively given, viz. the distance between the lower edge of the symphysis pubis and the sacral promontory, a measurement of considerable importance in the use of pelvimeters, to ascertain the conjugate diameter of the brim. This may be called the lower or inclined conjugate diameter, and it will be found to be, in most instances, half an inch more than the direct or superior conjugate diameter, being, in fact, the longest side of a triangle, having the conjugate diameter, and the breadth of the pubic symphysis for the other sides. The measurement of the circumference of the brim of the pelvis, and the proportion con- tributed to it by the sacrum, ilia and pubes respectively, announce a manifest difference between the pelves of the two sexes. In glancing over the appended table, it will be seen that the male pelvis exceeds the female in most of its vertical dimensions, while the female pelvis is larger in the horizontal di- ameters. The depth of the true pelvis, however, measured at the sacro-coccygeal column, is greater in the female, on account of the greater size of the sacrum in that sex, and also because of the less total vertical curvature. The depth from the pectineal eminence to the lowest point of the ischiadic tuberosities laterally, and at the pubic sjm- physis anteriorly, show, on the contrary, a great superiority in the male ; as also does the total depth of the whole pelvis, from the highest point of the ilium to the most de- pending part of the ischium, while the width between the iliac spines and crests are much greater in the female. The horizontal dia- meters of the pelvis may be said to depend upon the ilio-pubic element^ while the depth or vertical measurement depends solely on the ilio-ischion clement, so that, in the female, the former may be considered to prevail, and in the male, the latter element. This is re- 130 PELVIS. markable, as constituting the different pelvic properties of certain classes of animals. It will also be observed that the transverse diameter of the brim is the greatest in the dry bones, but this is so diminished by the presence of the iliac and psoas muscles and fascia, that, in the living female subject, the oblique is generally the best adapted to receive the long diameter of the fetal skull. The soft structures diminish the antero- posterior diameters of the brim by about a quarter of an inch , and the transverse, by half an inch ; the diameters of the cavity being lessened about a quarter of an inch ; a fact which it is necessary to bear in mind in estimating the width in the living subject. The measure- ments in the third double column were taken from fourteen male and eighteen female sub- jects in the dissecting room of King's College, London, and are compared in the first column with the contrasted measure- ments of the male and female pelvis given by Meckel, and quoted by most English writers on the subject; and in the second column with those given by John James Watt, in his work on the pelvis. Meckel. Watt. Diameters. Male. Female. Male. Female. Male. Female. in. lines. in. lines. in. lines. in. lines. in. lines. in. lines. Of the brim — Transverse 4 6 5 0 4 6 5 6 4 7 5 2 Oblique 4 5 4 5 4 2 5 0 4 7 5 0 Antero-posterior 4 0 4 4a 4 0 4 9a 4 0 4 5a Of the cavity — Transverse 4 0 4 8 Oblique 5 0 5 4 Antero-posterior 5 0 4 8 . . 4 8 4 8 Of the inferior strait — Transverse (inter-sciatic) 3 0 4 5b 3 2 4 Ob 3 5 39 4 4 b 4C\ A ntero -posterior 3 3 4 4 3 0 4 6 A 3 5 U 4 0 c Measurements. Between the anterior superior iliac spines - 7 8 8 6 d 9 0 11 Od 8 8 10 0 d Between the centres of iliac crests 8 3 9 4 e Depth of true pelvis — Between the upper and lower border of symphysis pubis - Between the ilio-pectineal eminence and ischial tu- 1 10 1 6 2 0 1 7 berosity - 4 10 3 6 4 5 3 8 Between the sacral promontory and tip of coccyx 4 10 5 0 4 6 ( 5 in. to | 6 in. Depth of whole pelvis — Between the iliac crest and ischial tuberosity 8 7 7 5f Between the anterior superior iliac spine and ischial tuberosity 6 5 6 0 „ posterior superior iliac spine and ischial tuberosity 6 0 5 5 Between the lower border of pubic symphysis and sacral promontory - 4 7 „ spines of ischia ------- 3 5 4 3 „ sacro-iliac joints (greatest breadth of sacrum) 4 3 4 8 * » 4 inches (Burns, Ramsbotham, Lee, Cloquet, Velpeau, and Baudelocque). Boivin). 4-3 inches (Rigby). 4 inches (Burns, Lee, and Cloquet). 4£ inches (Monro and Murphy). Increased to 5 inches or more by the mobility of the coccyx. 10 inches (Burns). 9'6 inches (Cloquet). 10 inches (Cloquet). 11 inches (Burns). 7 inches (Cloquet). 4 to 4J inches (Cloquet). inches (Monro and The circumferential measurement of the brim in well-formed males gave in my own mea- surements 2 inches to each of the ilia, 3 inches to each of the pubes, and 4| to the sacrum, which, allowing £ inch to each of the sacro- iliac cartilages and ^ inch to the pubic, gives a total circumference of 15^ inches. In the well-made female the ilia were found to be each 2£, the pubes each 3£, and the sacrum 5 inches, giving, with the same allowance for the sacro-iliac cartilages and £ inch for the pubic, a total of 17£ inches. Thus the superior size of the brim in the female seems to depend more upon the ilia than upon the pubes, although the direct distance between the ilio-pectineal eminence and the sacro-iliac joint differs little in the sexes, because of the greater curve made by the female ilia. The circumferential extent of the borders, at the plane of the inferior outlet in a female pelvis of average diameters, and dried with the sacro- sciatic ligaments attached, was 14 inches. In the fresh state it generally amounts to lo, as the ligaments shrink by drying, and would be extended to 16 inches, or more, by the ex- tension of the coccyx and the elasticity of the ligamentous portions.* * The circumferential measurement appears to be one not generally estimated as much as its utility in detecting variations of size depending upon shape would seem to call for, in the female pelvis. A reference to the subjoined table of variations of dia- PELVIS. 131 Burns gives also, in the female pelvis, the following distances: — 1. Between the symphysis pubis and inferior iliac spine, nearly - - 4 in. 2. „ sacro-iliac joint and the pubic crest of same side - - 4i „ 3. „ sacral promontory and the obturator notch - - 3£ „ •i. „ sacral promontory and the acetabula 3^ „ 5. „ acetabula anteriorly - 4} „ 6. „ posterior ridge of ilium and the su- perior and inferior anterior spines - 5 „ 7. „ centre of iliac crest and the brim of the pelvis, direct - 3£ „ One of these measurements was repeated by Velpeau, Stoltz, and Naegele, viz. from the sacral promontory to the centre of the cotyloid cavity, or sacro-cotyloid. Naegele in 54 and Stoltz in 40 female pelves, found the mean distance to be 3 pouces, 3 to 4 lignes (pied du Roi). Dr. Murphy, considering that the true salient point or promontory lies on a level above the real pelvic brim, at the sacro- lumbar fibro-cartilage, gives also three more measurements made in the " inclined plane of the promontory," one antero-posteriory be- tween the fibro-cartilage and the upper border of the symphysis, which he places at 4 inches, and two lateral, from the same point to the pectineal eminences, which are on an average about 3^ inches, but which are seldom equal, because of the great tendency to deviation of this promontory from the median line. The latter seem to coincide almost with those given by Dr. Burns between nearly the same points, and the former with the conjugate diameter of the brim. External measurements of the female pelvis, made on the living subject, have also been given, though from few data, as follows : — 1. External antero-posterior diameter, 7 to 8 inches. 2. External transverse, between iliac crests, 13 to 16 inches. 3. From great trochanter to the opposite sacro-iliac joint, 10 to 12 inches. 4. Depth of pelvis from top of sacrum to coccyx, 4 to 5 inches. From the first of these, according to Bau- delocque and Velpeau, 3 inches must be de- ducted for the thickness of the parietes, and from the second 4 inches. Boivin and Lacha- pelle doubted the utility of these measure- meter, will show how frequently the diameters are compensator}- to each other ; as this compensation may occur in diameters not usually measured, the circumferential extent seems in many cases to be required. Dr. Churchill gives the circumference of the brim as varying from 13 to 14£ inches in the female, much less than I have generally found it on the fresh subject after the soft parts were removed. ments generally, because of the great varia- bility in the thickness of the pelvic walls; and Dr. Davis has more recently found the thick- ness of the base of the sacrum to vary from 2 to 3 inches in 17 dead subjects. The measurements of Naegele and Otto, with a view to determine the presence of obliquely deformed pelves, are of great im- portance in the practice of midwifery, and may be best given in this place. Out of forty- two female pelves of medium size, the best formed they could obtain, these observers found the following measurements : — Mea- Greatest sure- Diffe- ment. rence. 1. From the sciatic tuberosity "1 in. lines. lines. of one side to the posterior 1 superior iliac spine of the [ 6 6 3 other side - - J 2 From the anterior superior "j iliac spine of one side to 1 the posterior superior of [ 7 3 3 the other side - - ] 3. From the spine of the last i lumbar vertebra to the an- 1 terior superior iliac spine 6 8 4 to 5 on both sides 4. From the great trochanter" of one side to the posterior 8r superior iliac spine of the O other 5. From the middle of the in-' ferior border of the sym- physis pubis to the pos- 6 4 2 terior superior iliac spine on both sides Danyan, pursuing Naegele's system, found the great rarity of perfectly regular female pel- ves. Out of eighty female pelves he found fifty- nine differ, in the first measurement, from 1 to 6 lines. In the second measurement he found a difference, in fifty-eight pelves, of 1 to 11 lines ; in the third, fifty-one differed from 1 to 7 lines ; in the fourth, sixty-two from 1 to 9 lines ; and in the fifth measurement, fortv- eight pelves had a difference of from 1 to' 9 lines. The table on the next page shows the great variety in the diameters of female pelves which may be considered as normal pelves. In males Dupuytren found the distance between the tuberosities of the ischia, in twenty-three subjects, to vary from 2 to 3i inches; and Velpeau, in forty subjects, to vary from 1| to 4 inches. In fourteen subjects I have found the least distance to be 3 inches, and the greatest 4 inches in the male, and measuring from the exact centres of the inner margin of the tuberosities. These observations on the male are of some im- portance with a view to the operation of lithotomy, when the stone is of great size. INCLINATION OF THE PELVIS.— By making, in a well-formed subject, a direct vertical section of the spinal column, and drawing a line through the centres of the bodies of the axis and last lumbar vertebra, and by com- paring with the transverse plane of such a K 2 132 PELVIS. line those of the superior and inferior outlets pelvis to the vertebral column is obtained, of the pelvis, the general inclination of the The line so drawn will generally be found to VARIATIONS in the Diameters of healthy Female Pelves. Dr. Murphy (in 18 Cases). Taken by the writer in the King's College dissecting rooms (in 18 Cases). Extremes. Most fre- quent. Extremes. Most fre- quent. Inclined plane of promontory — inches. inches. inches. inches. Antero-posterior - *3| or 3| to 5| 41 to 41 To left pectineal eminence- *3 or 31 to 4| 31 to 3| To right pectineal eminence *2| or 3£ to 5|j 33 Brim — Antero-posterior *3| or 31 to 51 4 3^ to 4f 41 Transverse f3| or 4i to 5| 53 5 to 5| 5 oblique (R.ght; : *4| or 4f to 5i *4| or 4f to 51 5 and 5y 4|to5i 5 and 51 Between promontory and lower edge of symphysis pubis - . 3TT) to 51 4f and 5 Cavity — Antero-posterior *4^ or \\ to 5| 5 4| to 5| 4ij and 51 Transverse *3| or 41 to 5£ 5 - . Between ischiadic spines _ _ 31 to 41 41 Outlet — Antero-posterior Transverse J3| to §4| §31 tof 5 4 to 4i 4| to 4| 31 to 41 3f to 4f 4 Oblique (6 cases only) _ 31 to 41 4 Angle of pubic arch - 45° to 100° 70° to 90° Like male pelvis, diameters small. Smallest pelvis, transverse diameter of cavity 4|, of outlet 4|. Belong to the same pelves respectively (compensating diameters). pass also through the bodies of the first dorsal and second lumbar vertebrae across their centres. The curved line of the vertebras, in most well-formed subjects, cuts the straight line at these two points, in passing from the cervical to the dorsal, and from the latter to the lumbar curve. The plane of the pelvic brim has been termed by Naegele and the brothers G. and E. Weber the superior plane of the pelvis, and that of the inferior outlet the inferior plane. These observers measured the angle formed by these planes with the ground-level in the standing position, i. e. with the horizon, or with a plane drawn horizontally, at right angles, to the above-mentioned transverse vertical plane, which, in the erect posture, was found to be perpendicular to the base of support. The angle which the superior plane of the pelvis forms with the transverse vertical plane or with the horizon is termed by them the angle of inclination of the pelvis, or the pelvi- vertebral angle (fig- 84. page 134*.), (ae, ec). It is remarkable that, in man only, are the boundaries of the superior outlet in one plane, i. e. in man only is the direction of the superior pubic ramus in the same plane with that of the cotylo-sacral rib of the ilium. In all other ani- mals, as far as my own observations go, the pubis is bent backward or forward, so as to make an angle with the ilium, and the pelvi- vertebral angle is thus resolved into two angles, a vertebro-iliac and an ilio-pubic, The angle of the superior plane was found by the Webers on the dead body, by fixing the connected spinal column and pelvis of a recent well-made subject, in plaster of Paris, to preserve the natural position, then making through the whole a direct vertical section, and afterwards measuring off the angles. On making a transverse vertical section through the centres of the heads of the femurs and cotyloid cavities, they also found that, when the body is in the erect position and the pelvis at the proper angle, the coty- loid notch and depression, and the fibres of the ligamentum teres, have an almost directly vertical direction, and fall exactly in the trans- verse vertical plane of the vertebrae (see fg. 87. page 140., in which the line a a' lies in the plane of the transverse vertical section). It will be further seen, by inspecting the figure, that this plane, being continued downwards, crosses the obturator foramina, and falls very nearly in the line of suture of the ischio-pubic rami. And this will be found to be the case, with a plumb line dropped from the sacral pro- montory, which is cut by the above plane in the erect position of the pelvis. A detached pelvis may be placed in the erect living po- sition, consequently, by keeping the poste- rior part of the notch the most depending point of the cotyloid brim, and its inclinations will then accord with those taken in connec- tion with the spine. In the consideration of these pelvic angles it must be borne in mind that the direction of the curve of the three last lumbar vertebrae, below the point where the great dorsal con- cavity terminates, is such that, if prolonged upwards, the axial line would pass out at the junction of the manubrium with the body of the sternum. This makes the pelvi-lumbar angle much less in man than the whole pelvi- vertebral ; a circumstance to be borne in mind in comparing them with those of animals. In fact, the transvertical section just mentioned passes through the body of the third lumbar vertebra considerably posterior to its centre in most cases (see a, b^g. 84. page 134.). PELVIS. 133 By an inverse method, proceeding on Roederer's plan from the horizontal plane (Jig. 84. #, rf), Naegele determined, with great care, the angle of the inferior plane of the pelvis in the living female. In 500 well-formed living females placed in the erect position, he mea- sured the respective distances from the ground, of the tip of the coccyx, and of the lower border of the pubic symphysis. He found that in 454 the extremity of the coccyx was higher than the symphysis pubis, the greatest difference being 22 lines. In twenty-six only was it lower, the greatest difference here being 9 lines, and in twenty they were equal in height from the ground. In eleven pelves where he had the opportunity of verifying his observations after death, he found and figured one perfect pelvis, in which the tip of the coccyx was 8 lines higher than the lower border of the symphysis, which corresponded very nearly with the mean elevation of the coccyx above the symphysis, viz. 7' I lines, drawn from the observations above detailed. From this he deduced the inferior angle of inclination of the pelvis (fg d) to be 10° to 1 1° with the horizon (g, d). In a similar manner, in fifteen living males the brothers Weber ascertained the range of the altitudes of the coccyx and pubis to be from 10 millimetres, the extreme difference when the coccyx was lower, to 33*3 millimetres when the coccyx was higher than the lower border of the symphysis pubis, the mean height of the coccyx above the pubis being thus 23-1 millimetres. Then, by measuring the distance between the plumb lines dropped from each of these points, the coccyx and pubis, they ascertained the mean distance to be 75'8 millimetres. From these measurements they obtained the angle of the inferior pelvic plane with the horizon 160>51. By measuring, in two dead subjects, the depth of the symphysis pu- bis, and the direct vertical distance from the tip of the coccyx to the sacral promontory, thev deduced the angle of the superior pelvic plane. The superior angle, however, cannot with any certainty be calculated from the inferior in the living subject, on account of the un- certain length and curve of the sacro-coccygeal column. In a well-formed or standard pelvis the two lines of the superior and inferior planes, when prolonged anteriorly, cut each other about l£ inch anterior to and below the pelvis (at r), containing an angle of about 50° (e cf) ; but this will vary with the length of the sacro-coccygeal column. According to Naegele the point at which the superior plane emerges posteriorly is also very variable. Most frequently it is the spinous process of the second lumbar vertebra, often that of the first, and sometimes between the second and third. Generally the upper border of the symphysis pubis uas 3 inches, 9 to 10 lines lower than the sacral promon- tory, and on a level with the union of the second and third coccygeal bones. The sacro- vertebral projection I have generally found to be about the level of the anterior superior iliac spine in the male, and a little below this point in the female, in a straight position of the body. The following table shows the pelvic angles of inclination in the sexes, and their difference in this respect, and is drawn from the above- mentioned experiments of the Webers on male, and of Naegele on female subjects. Male Female (Nae- Angle of Inclination (Weber). gele). of superior plane, or pelvic brim. With transverse > vertical plane - 3 155° 150° to 151° With horizon 65° 59° to 60° Of inferior plane, or outlet. With transverse \ vertical plane - $ 106° 51' 101° to 102° With horizon 16° 51' 10° to 11°* B}r the inspection of the above table the greater inclination of the pelvis to the spine in the male will become evident, constituting another distinguishing characteristic of the sexes. The older observers estimated the pelvic angles too low, as in the incorrect drawings of Albinus, Levret, and Cloquet, where the superior angle is given as 35° with the horizon, andr by Osiander, at 30°. Carus gives the superior at 55°, and the inferior at 11° with the horizon. Angles of the anterior and posterior pelvic walls with the transpose vertical plane. — The pelvic inclination, in the opinion of Cru veilhier, depends upon the angle which the sacrum forms with the spinal column, giving more or less of obliquity to the innominate bones on each side. This angle (fig. 84. next page, a e i, and fig. 1 1 2. I. fa g, page 173), which may be called the sacro-vertebral angle, I have, in as many opportunities as have oc- curred to me, endeavoured to ascertain and establish, with a view of comparing it with the pelvi-vertebral angle in the two sexes. To do this I made a vertical section of the pelvis (with as many vertebrae as possible attached to it), from behind forward in the median line, which showed clearly the angle made by the sacrum. Then, by intersecting the line of the transverse vertical plane of the spinal column drawn as before mentioned, by a line drawn in the mean direction of the three first sacral vertebrae through the centre of their bodies, angles closely approximative to the sacro- vertebral angle in the living subject were ob- tained, showing the following results: — * Weber, however, found the angle of the inferior plane with the horizon to be but little less marked than that of the male ; making it 4°'5 more than the angle of Xaegele here given. Naegele remarks that the inferior angle is much more variable than the superior in ordinary cases. K 3 134 PELVIS. In twenty-five males, Nine were from 11 6° to 112°, five from 115° to 117°, nine from 120° to 125°, and two only 130°. In twenty-five females, Nine were from 120° to 125°, eight from 128° to 130°, five from 133° to 140°, two were 145°, and one, an aged subject, 118° only. Fig. 84, Diagram (slightly altered from Naegele) of a well- formed female pelvis, showing the angles of inclina- tion and axes. From these we may deduce 117° as the average sacro-vertebral angle in the male, and 130° as the same angle in the female. This remarkable average difference of 13° shows the much greater suddenness of the altera- tion of direction in the spinal column at its sacral extremity in the male subject, and is much greater than the difference of 5° to 6° in the pelvic inclination of the sexes com- pared in the tables of Weber and Naegele. But, in order more clearly to ascertain it the pelvic inclination invariably depended upon the variations of the sacro-vertebral angle, I compared the sacro-vertebral and pelvi- verte- bral angles in nine male and nine female sub- jects. In the former, I found the difference between these angles to vary from 5° to 35°, and, in the latter, to vary from 5° to 25°. In one instance only, in a male, the sucro-verte- bral was as large as the pelvi-vertebral angle. From these observations, which were very carefully taken, it would seem that the total pelvic inclination does not exactly depend upon the sacro-vertebral angle ; and that, in males, where the average pelvic obliquity is a little greater, the average sacro-vertebral angle is much and disproportionately less. These results contradict, also, the assumption somewhat indefinitely stated by Blumenbach and others, on the authority of Bonaccioli, of Ferrara, that the sacrum inclines more backward, and that the sacro-vertebral angle is more promi- nent in the female than in the male. If the long diameter of the pubic symphysis be continued in its direction downwards and backwards, it will, in a well-formed female pelvis, cut the transverse vertical plane of the spine, also prolonged, at an angle of 50° to 55° (^.84.a &&), which will be found to be about the complementary or opposite angle to the sacro-vertebral angle in the female. This shows the general parallelism of the anterior or pubic wall of the pelvis, with the upper part of the posterior or sacral wall, although, on account of the rapid thinning of the latter as it descends, its pelvic surface seems to diverge from the pubis. Naegele found the anterior pelvic wall to be often at right angles to the plane of the inlet, but the posterior generally somewhat more than a right angle. The great obliquity of the symphysis pubis to the transverse vertical plane of the vertebrae is one of the great characteristics of the human pelvis, as will be seen hereafter in the consider- ation of the comparative anatomy of the pelvis. The angle formed by the symphysis pubis with the horizon is given by Cuvier from 75° to 95°. This is much too large ; from 35° to 40° is the true angle of the symphysis with the horizon in the human subject. Ilio-lschlal angle. — While the pubis in the human subject is continued in the same right line with the mean direction of the ilium, which coincides with the cotylo-sacral rib of that bone, the ischium is inclined backwards^ forming an angle of 1 10° to 115° with the same rib of bone (see^g. .? 12. 1. a c d, page 73.), so that, while the pubes are directed transversely with regard to the pelvic cavity, the ischia are directed vertically along, and forming the sides of the cavity. This arrangement will also be found to be an important characteristic of the human pelvis, when compared with those of the inferior mammalia, in which the reverse of this arrangement will be found to prevail, viz., the continuation of the ischia in the line of the ilia, and the formation of an Mo-pubic angle. Angle of IschiO'publc arch. — The angle at which the ischio-pubic rami tend toward each other, has been placed by Watt at 60° to 80° in the male, and 90° in the female ; and by Scemmerring at 75° for the male, and 95° for the female (see Jigs. 83, 80.). AXES OF THE PELVIS. — The term axis is applied anatomically to the line of direction of any surface or plane, and, as it implies a right line, drawn at right angles to that surface or plane, it can only be applied with propriety to the outlets of the pelvis. As applied by some authors to the line which indicates PELVIS. 135 the central point in any given plane of the pelvic cavity, it then becomes really a curved line, made up of an infinite number of perpen- diculars drawn from any number of planes radiating from a centre placed anterior to the symphysis pubis. Since it is with regard to the mechanism of parturition principally that the axes of the pelvis are of importance, the angles formed by them, with the vertebral plane (transverse vertical), are stated in refer- ence to the standard female pelvis more par- ticularly. In the male subject, these angles will be somewhat greater, from the greater inclination of the pelvis in that sex. The axis of the brim is a line drawn from the centre of the superior plane, and at right angles to it (fig. 84. /, w). This line cuts the prolonged vertebral plane exactly half-way between the symphysis pubis and the upper part of the third sacral vertebra, and forms with it an angle of about 60° (a o /). It may be taken also as the most nearly approxima- tive axis of the pelvic cavity above that point. When prolonged at each end, it passes out at the umbilicus, and impinges upon one of the two last coccygeal bones, in a well-formed female. It is evident, however, that from the, great variety of the sacro-coccygeal curves, that the point where this line meets the coccyx will be variable. Hence, the observa- tion of Watt, that a line joining the tip of the coccyx and the centre of the superior plane cuts the latter at an angle of 75°, is too defi- nitive. M. Naegele, however, found that in a large number of female pelves, this line did meet the coccyx at some point or other. The axis of the inferior outlet (w, p) is drawn at right angles to the centre of the in- ferior plane, and falls midway between the sciatic tuberosities. From the mobility of the coccyx, it will vary with the motion of that bone from its ordinary position to a position of extreme extension. In the ordinary posi- tion of the coccyx, this axis forms, with the vertebral plane, an angle of about 10°, and meets it near the centre of the upper surface of the body of the first sacral vertebra, im- pinging there upon the sacral promontory. When the coccyx is in a position of extreme extension, however, its tip describes the curve ?», *, this axis is thrown more forward (n, q\ and forms a less angle with the verte- bral plane ; while the plane of the inferior outlet itself is depressed (g, s), and its angle with the horizon (s g d] diminished. The curved line (/, o, n, p), which indicates the continued centres of the planes of the pelvic cavity, may be divided into three por- tions indicated in the figure by the two dotted planes (c, h and c, r). The part from the plane of the outlet to the upper dotted plane (c, h}, impinging upon the third sacral ver- tebra, may be considered to coincide, for all practical purposes, with the line of axis of the brim (/, m). The inferior dotted plane (c, r), drawn, like the former, from the point of junc- tion of the planes of the brim and inferior outlet, to the tip of the last sacral vertebra, includes, with the upper dotted plane just mentioned, a parabolic curve (o, n), which does not quite coincide with the arc of a circle drawn from the ante-pubic centre (c). These two portions of the axes of the cavity arefaed, from the immobility of the pelvic walls which include them. But, below the inferior dotted plane to that of the outlet, the axis is di- rected more forwards (n, 140° 140° made, male It will be remarked that the greatest dif- ference from the adult is observable in the sacro-vertebral angle, which is from 10° to 15° greater than the average female adult, and from 23° to 28° greater than the average male adult. I should here state, also, that the results of my own measurements of the angle of the superior pelvic plane in adult male subjects, have given somewhat less angles than that stated by Weber. According to Ouveilhier, a horizontal line, from the upper border of the pubis, meets the posterior wall much lower in the infant than in the adult, though the point at which he places it in the adult, viz., a little below the base of the sacrum, is much too high in the natural position of the pelvis, as will be seen by inspection of the diagram (fg. 84.). In all the infant pelves 1 have just given, the tip of the coccyx reached as low as the lower border of the symphysis pubis ; both these points exactly coinciding with a line drawn perpendicular to the transverse verti- cal plane. This may, perhaps, be attributed to the greater flatness of the sacro-coccygeal wall in the infant, extending it further down- ward. In No. 5. the male child at full term, the angle of inclination of the pubic tympkyat to the transverse vertical plane was only 25°, but in the last female child it was, 40°, both being less than the mean adult angle, 50°, before given, and showing, like the sacro- vertebral angle, a greater tendency to parallel- ism with the spine, as in the inferior animals, an analogy which is also seen in the elongated conjugate diameter. Resulting from this tardy development of the pelvis, the bladder and greatest portion of the rectum, in the child at birth, are con- tained almost entirely in the abdominal cavity, on a level with the ilia or false pelvis, and only descend gradually afterward into their adult position with the slow development of the pelvic bones, assuming their permanent position about the period of puberty, a cir- cumstance very necessary to be borne in mind in operations on these viscera in chil- dren below that age. Hence one cause of the greater prominence of the belly in children from the additional number of its visceral contents. PELVIS. 137 According to Dupuytren, the female pelvis differs very little' from that of the male till puberty, at which period it has a general triangular form in both sexes, but, after that period, it becomes rapidly developed, and soon assumes its distinctive sexual cha- racter. The transverse diameters begin to exceed the conjugate, and, in the female, attain a great preponderance, constituting one of the great characteristics of the fully formed human pelvis, as distinguished from that of the lower animals. In Autenrieth's method of calculating the pelvic dimensions, the dorsal, or posterior part, bears a proportion to the anterior or abdominal part, as 10 to from 11 to 14*, in the infant of t\vo years ; while, in the adult pelvis, it was as 10 to from 16 to 22. In advanced adult age, the pelvic inclination is said by Cruveilhier to be increased in con- sequence of the forward curvature, or droop- ing of the spinal column, which tends to arrive at the horizontal position, as in quadru- peds. To keep the centre of gravity between the lower .extremities, the femurs, in old persons, are more flexed upon the pelvis, so as to be more directed towards the line of the superior pelvic plane. 1 have found, however, that in old subjects, although the angle of the pelvic plane with that of the whole spinal column is increased, yet the angle with the lumbar vertebrae only, is not so much changed, and that, apparently, the increased muscular traction on the sacrum and posterior part of the ilia by the muscles of the back act- ing upwards, and of those of the front of the thigh acting downwards, upon the anterior part of the pelvic lever, in order to pre- serve the erect position, produce this in- creased obliquity of the pelvis, which is ge- nerally accompanied by a corresponding de- crease of the sacro-vertebral angle. This will be more fully comprehended when consider- ing the mechanism of the pelvis. MUSCULAR ATTACHMENTS OF THE PEL- VIS.— To afford a fixed point for the attach- ment of the numerous and powerful muscles acting on the trunk and extremities is one of the important offices of the pelvis. These may be classed as posterior spinal and abdo~ minal groups acting on the trunk and spinal column ; extensor, flexor, adductor, abductor, and rotator groups acting on the lower extre- mity ; and perineal grou])s forming the move- able floor of the pelvis and acting on the genital and excretory organs. 1 . ^Muscles acting on the trunk and spine. — The posterior spinal group. — The longissimus dorsi and multijidus spints, to the upper part of the posterior surface of the sacrum ; the interspma/es, to the superior border of the sacral crest; and, according to some, the ex- tensor coccygis, to the contiguous posterior surfaces of the sacrum and coccyx ; the sacro- lumbalis, to the middle part of the posterior third of the iliac crest, and to the contiguous sacral surface ; and the laHsshnus dorsi, through the lumbar fascia to the external lip of the posterior half of the iliac crest and to the sacral crest. This muscle acts on the arm. The abdominal group. — The obliquus exter- nus and internus, and transversalis abdo- minis, to the external lip, middle ridge, and internal lips respectively of the iliac crest, and also by their aponeurotic tendons to the angle, crest, spine, and pectineal line of the pubis (the external oblique tendon, under the name of Poupart's ligament, stretching across, from the anterior superior iliac spine to the spine of the pubis, and, under the name of Gim- bernat's ligament, passing backwards to the linea-ilio pectinea; and the internal oblique and transversalis tendons enclosing the rectus abdominis muscle, and uniting to form the conjoined tendon) ; the quadratus lumborum, to the posterior fourth of the inner lip of the iliac crest ; the rectus and pyramidalis abdo- miius, to the crest of the pubis; and the psoas parvus, when present, to the pectineal eminence. 2. Muscles acting on the leg. — The flexor group. — The rectus femoris, to the anterior in- ferior iliac spine and outer part of the coty- loid rim; the iliacus, to the whole anterior concave surface of the iliac wing — the psoas magnus is not attached to the pelvis, but acts upon it by passing over it along the pelvic brim ; and the sartorius, to the anterior supe- rior iliac spine and notch below it. The extensor group. — The biceps flexor cntris, semitendinosus, and semimembranosus, to the depending middle and posterior parts of the ischial tuberosity ; and the gluteus maxiinus, to the quadrilateral gluteal impres- sion on the dorsum of the ilium, to the pos- terior surfaces of the two lower pieces of the sacrum, and of the two or three upper pieces of the coccyx, to the oblique sacro-iliac and great sacro-sciatic ligaments, and to the lum- bar fascia. The adductor group. — The adductor magnus, to the anterior part of the ischial tuberosity, and to the united ischio-pubic rami ; the ad- ductor longus, to the anterior surface of the angle of the pubis ; the adductor brevis below the foregoing, to the same surface ; the pec- tineus, to the spine, pectineal line, and hori- zontal ramus of the pubis ; and the gracilist to the rough internal border of the ischio- pubic rami and symphysis pubis. The abductor grouji. — The gluteus medius, to the dorsum of the ilium, between the crest and superior curved line ; the gluteus minimus, to the same surface between the curved lines ; and the tensor vaginte femoris, to the outer surface of the anterior superior iliac spine. The rotator groitp. — The pyriforrnis, to the anterior surface of the sacrum between the four upper sacral holes, and passing out through the great sciatic notch ; the obturator externus, to the inner half of the external cir- cumference of the obturator foramen, and to the external surface of the membrane closing it; the obturator internus, to the internal surface of the same ligament, and to the borders of the foramen, and also to the surface of bone oppo- site the cotyloid cavity (this muscle passes out through the small sciatic notch, over which 133 PELVIS. it is bent as over a pulley) ; the gemcllus su- perior, to the outer surface of the ischiadic spine; the gemellus inferior, to the posterior extremity of the ischiadic tuberosity ; and the quadratus femoris, to the external border of the same tuberosity. 3. Muscles acting on the perineum and ge- nitals.— The posterior perineal group. The levator ani, to the middle of the inner surface of the symphysis pubis, to the inner surface of the ischiadic spine, and to the tip of the coccyx; the ischio-coccygeus, to the same inner surface of the ischiadic spine, to the lateral border of the coccyx, and to the inner surface of the small sacro-sciatic ligament ; and the sphincter ani, to the tip of the coccyx. The anterior perineal group. — The trans- versus perinei, to the middle of the inner border of the ischial tuberosity; the accelerator urinfB (or, in the female, the sphincter vagince), to the anterior part of the inner border of the ischial tuberosity ; the erector penis (or, in the female, clitoridis), to the ascending ramus of the ischium ; and the compressors urethra;, to the descending ramus of the pubis, and to the sub-pubic ligament. FASCIAL ATTACHMENTS. — Besides the fore- going, the pelvis also affords attachment to many important fascics, which are susceptible of division into lumbar, abdominal, crural, pelvic, and perineal. The lumbar fascia is formed by the junction of the tendon of the latissimus dorsi muscle with the fascia vertebralis, and the united posterior tendons of the internal oblique and external division of the transversalis tendon, and it is attached along the sacral crest and posterior surface of the fourth sacral bone, and to the posterior half of the iliac crest, enclosing the sacro-lumbalis muscle. The abdominal fascia; are three in number, viz., the fascice transversalis, attached along the inner lip of the iliac crest, to Poupart's ligament, and to the crest, spine, and pec- tineal line of the pubis ; the fascia of the qua- dratus lumborum muscle, or anterior division of the tendon of the transversalis, attached to the inner lip of the posterior fourth of the iliac crest, and to the ilio-lumbar ligament; and the iliac fascia, attached to the ilio-lumbar ligament, along the inner margin of the iliac crest, and to the anterior superior iliac spine. The crural fascia or fascia lata is divided into three portions, named, from their respective attachments to the three portions of the inno- minate bone, iliac, pubic, and ischiadic. The outer lip of the iliac crest, the anterior superior spine, and Poupart's ligament, give attachment to the iliac portion, which separates the lateral abdominal from the external leg muscles ; the spine, crest, angle, pectineal line, and descend- ing ramus of the pubis, to the pubic portion, which separates the internal leg muscles from the anterior abdominal tmd anterior perineal group of muscles ; and the tuberosity and ascending ramus of the ischium to the ischiadic portion, which separates the posterior leg muscles from the posterior muscles of the perineal group. The pelvic fascia is composed of two por- tions, the rccto-vesical and obturator, which, having a common attachment to the anterior surface and promontory of the sacrum, to the anterior and lateral parts of the pelvic brim, and to the iliac fascia, separate opposite the line of origin of the levator ani muscle, which arises between them, from the symphysis pubis to the ischiadic spine. The obturator division is attached to the inner margins of the ischiadic tuberosity and ischio-pubic rami, being con- nected with the falciform margin of the great sacro-sciatic ligament behind, and secluding the obturator muscle from the ischio-rectal fossa ; the recto-vesical division, forming the anterioi ind lateral true ligaments of the bladder, is attached to the posterior surface of the symphysis pubis above the origin of the levator ani, and to the inner surface of the ischiadic spine. The perineal fascia is divided into two por- tions, deep and superficial, which enclose be- tween them the superficial muscles of the anterior perineal group, and also the bulb of the urethra and the crura of the penis. The deep perineal fascia or triangular ligament is subdivided into two layers, anterior and pos- terior, which enclose between them the mem- branous urethra, with its compressor muscles and Cowper's glands. They are both attached to the lower border of the pubic symphysis and sub-pubic ligament, and to the inner border of the united ischio-pubic rami, and intervene between the posterior and anterior perineal groups of muscles. The superficial perineal fascia covers in the anterior perineal region, and is attached to the anterior part of the inner border of the ischio-pubic rami, and to the anterior surface of the angle of the pubis. The crura of the penis, or, in the female, those of the clitoris, may also be mentioned as implanted on the rough inner border of the ischio-pubic rami about their junction ; as well as the round uterine ligament, in the fe- male, to the anterior surface of the pubis. MECHANICS OF THE HUMAN PELVIS. — When we consider the pelvis with regard to its architectural adaptations, and compare it with the principles of engineering, we are struck with the beautiful simplicity of the means by which it combines strength with elasticity, and lightness with capacity and unity of design. The weight of the trunk is to be transmitted through the lumbar ver- tebrae to the sacrum, and from thence to points of support, which vary with the posi- tion of the inferior extremities. In the erect position, these points are the femora. In the sitting position they are the tuberosities of the ischia. The experiments of Weber have proved that though the centre of gravity of the trunk itself (without the legs) is placed in the transverse vertical plane as high as the sterno-xiphoid joint, yet the centre of gravity of the whole body, as marked by the point of section of the before-mentioned transverse- vertical with a horizontal plane, is placed only PELVIS. 139 8'7 millimetres above the sacro-lumbar joint, or just above the pelvic arch. All weight on the arch, such as that of the trunk, is sup- ported most easily when its line of gravity falls through this part, and coincides with that of the whole body in the transverse vertical plane, and the trunk will be found to be thrown into such a position, when supporting heavy weights, as will tend to produce this effect. And, according to the researches of Ilokitanski, when the sacro- vertebral angle and pelvic inclination is increased, as by hip disease, there is always a compensatory curve of the spine backward, to keep the centre of gravity above this point. In artificial constructions for the purpose of transmitting a weight downwards from a central to two lateral points, a segment of a circle, or arch is most commonly made use of, and generally consists of two lateral curved portions, composed of separate parts or voussoirs, with an interposed substance between them called a keystone or crown- piece, of a wedge shape, and placed with the broad end uppermost. This wedge shape exactly corresponds to the interval which would be left between the lateral curved pieces, having their ends cut square. Any force operating on the keystone from above tends only to drive the broader part of the wedge further between the lateral pieces, at the same time pressing them nearer to each other, and so to increase the firmness of the arch, so long as the extremities are firmly fixed in the ground and prevented from start- ing outwards, which is generally accomplished by means of abutments. Constructed upon this plan, the pelvis pre- sents two lateral curved thickened buttresses or columns, passing from the cotyloid to the sacro-iliac articulations, and two others pass- ing on a plane posterior to these from the tuberosities of the ischia along their de- scending rami, and through the ilia to the same sacro-iliac articulations; and interposed between each of these corresponding lateral pieces is the common keystone of both the arches thus formed, the wedge-shaped sacrum. The sacrum thus forms the common cul- minating point of two arches, viz., the cotylo- sacral or standing arch, and the ischio-sacral or sitting arch. And the planes of these two arches are so directed as to coincide or be- come applied to each other at the top of the great sciatic notch, as may be seen by reference to the diagram (fg. 86. A, a a'). In this comparison, however, it must be borne in mind, that the extreme tenacity and strength of the material used, bone, obviates the ne- cessity of the use of many pieces in the lateral portions, such as the "voussoirs" of stone arches, and is more analogous to the iron materials sometimes used for this purpose. And it is in these lines of pressure that we find the bulk and strength of the osseous structure of the pelvis most displayed. The span of the cotylo-sacral arch being greater, and more elliptical in the female than in the male, where it is almost circular, renders them less able to support heavy weights; and on account of the greater distance to Fig. 86. A, diagram of the pelvic arches — b, a, b', cotylo- sacral arch ; c, a, c1, ischio-sacral arch ; 5, d, I/, cotylo-pubic tie ; c, d, d, ischio-pubic tie. B, diagram of pelvic levers : — c, a, line of gravity ; F, b, pubic lever; F, w, cotylo-sacral lever; w, P, posterior spinal or iliac lever ; F, c, direction of spinal power ; w, c, direction of spinal weight ; F, cotyloid fulcrum ; d, femoral support. which it separates the femurs, contributes to produce the waddling gait in running which is characteristic of this method of female pro- gression. Instead of abutments to prevent the extre- mities of the arch starting outwar.ls, we often see, in artificial constructions, a connecting link or tie extending between these extremi~ ties to hold them together, or the circle of which the arch is a segment is completed below, as in tunneling. Such a tie and completion of the circle we have in the horizontal rami of the pubic bones, for the cotylo-sacral arch, and in the united ischio-pubic rami, for the ischio-sacral arch ; and they are connected in front, at the pubic symphysis, exactly as these two arches themselves are behind at the sacro-iliac joints. By the vertical ischio-pubic arch thus formed, that portion of the pressure which has a tend- ency to push forward and upward the extre- mities of the ischio-sacral arch, is supported and thrown upon the cotylo-sacral arch, the whole weight of the trunk, in a sitting posture, being thus divided between them The ischio- pubic rami are the parts of the pelvis most liable to fracture, according to Cruveilhier, from the application of force acting on the ischia. The cotylo-pubic arch not only resists the starting outward of the ends of the cotylo- 140 PELVIS. sacral arch, but it resists their displacement inwards, which would result from the pressure of the femora in the direction of the necks of these bones. The effect of this pressure, when the pubes yield to it, is shown in the de- formity which has been termed the rostrated pelvis, resulting from the crushing of these bones together. The cotylo-pubic arch also receives, in its concavity, part of the weight of the abdominal viscera, though, from the attachment of these to the spine, their chief weight is concentrated upon the common centre of pelvic arches, — the sacrum. The ilia are also generally supposed to support the intestines in a great measure ; but this support, on account of their great obliquity in the erect position, cannot be so important as is commonly imagined, except, as in the case of the coecum and rectum, through peritoneal attachments. The human pelvis, when thus taken .in conjunction with the thorax, forms the base of a cone, the apex of which is the neck, a disposition for supporting the contained viscera which the erect position demands, and which contrasts strongly with the structure of quadrupeds. Again, the cotylo-sacral and pubic arches on each side, united at their extremities in the acetabula, form two lateral arches, on the centres of which rest the thigh bones. Against the lateral pressure exercised by the thigh bones, these two arches, connected, at their anterior and posterior extremities, by the symphysis pubis and sacrum, form, as Mayo observes, an elastic hoop. The ischia also contribute to this resistance against lateral pressure, and form, with the two other por- tions of the innominate bones, a sort of arched tripod, on the apex of which the femur is supported. In addition to the buttresses already de- scribed, there is, placed vertically above the cotyloid cavity, a thick rib of bone, which transmits to the arched crest of the ilium, and through it and the sacro-iliac joint to the sacrum, a portion of the direct vertical pressure from the heads of the thigh bones. This thickened portion of the iliac wing has been mentioned in the general description of the bone as impinging on the iliac crest in the middle of its anterior curve. The division of the pressure thus produced, no doubt calls into action much more com- pletely the elastic resistance of the pelvis, in sudden increase of weight. Thus in the sacro-iliac joint meet three buttresses or thickened lines of pressure, of which the direct cotylo-sacral is the central and principal one, the ischio-sacral the lowest and next in strength, and the superior or indirect cotylo' sacred the weakest. But, besides merely supporting quiescent superincumbent weight, the pelvic arches are required to resist and break the force of shocks and concussions meeting with the inertia of the trunk, and passing from the lower extremities of the body to the vital and delicate cranial and thoracic structures. These dynamic requirements are met by pe- culiar modifications of the simple arch, com- bining with it, by an admirable adaptation, the qualities of an elastic spring. First, the cotylo-sacral arch, on which the greatest number and force of shocks falls, is not placed vertically, but obliquely upivards and backwards, while the cotylo-pubic arch, being united to it at its extremities, and con- tinued in the same plane over the femoral supports, forms the anterior arm of a bent lever of the first order, of which the cotylo- sacral arch is the posterior curved arm, the spinal column the weight, and the heads of the femurs the fulcrum (see Jigs. 87. and 86. B). Fig. 87. Drawing of a section of the pelvis in the cotylo- sacral arch, removing the left iliac wing, a, a', line of fulcrum falling in the transverse vertical plane of trunk; c,c', line of weight passing through centre of sacro-iliac joint ; b,V, line of power or pubic pro- jection ; d, d1, line of sacral projection ; e,f, cotylo- sacral curve ; a!, U, pubic arm of lever ; a', c', co- tylo-sacral arm ; a', d', length of gluteal arm ; c', d', posterior spinal arm; g, posterior iliac projec- tion. The anterior or pubic arm of this lever giving insertion to the powerful extensor muscles of the thigh, which represent the power, is thrown upwards by the operation of downward force on the crown of the cotylo-sacral arch, calling these muscles into contractile reaction, which overcomes gradu- ally the force of any shock operating at the posterior extremity of the pelvic lever over the fulcrum of the thigh bones. In well- formed male pelves, the pubic arm of this lever is increased in power by being longer than the cotylo-sacral by £ or £ of an inch, the one being 2 inches, the other 1£ inch, in PELVES. 141 direct distance from the centre of the cotyloid support (fig. 87. a' b' ', a' f the same side, 4-i inches. At the outlet, the an- tero-posterior diameter (measuring from the apex of the sacrum) was, 4£ inches; the transverse, 3£ inches. The breadth of the sacrum was, 3* inches, and the length the same. The a'ngle of the sub-pubic arch measured only 67£°. In this pelvis also, al- though a female, the prevailing size of the antero-posterior diameters, and the limited breadth of the sacrum and transverse dia- meter of the outlet, as well as the exceedingly small expanse of the sub-pubic arch, are very remarkable, and are hardly accordant with easy labours, unless from the special adapt- ation of the foetal head. Dr. Vrolik of Amsterdam, who devoted much attention to this subject, remarks, that the Negro male pelvis is contrasted widely from the female of the same race, in being strong, dense, and massy, while that of the female is light and delicate in appearance, although not presenting the transparent thin parts that the pelvis of the European female exhibits. But the Negro male pelvis given in the table is remarkably light, slender, and well formed for a man of so considerable a stature, and the centres of the ilia very concave, and as thin as in most pelves I have seen ; nor are the ischial tuberosities at all dispropor- tionately large nor turned out, nor the pos- terior superior iliac spines elevated. Vrolik points out also, as marks of degradation in type in the Negro female pelvis, the vertical direction of the ilia, their elevation at the posterior superior spines, and the approxima- tion of the anterior iliac spines to the cotyloid cavity, together with the narrow transverse and antero-posterior diameters, the anterior sacral projection, the general elongation of the pelvis, and the greater acuteness of the sub- pubic angle. This author considers these pe- culiarities to resemble the formation of the pelvis in the Simue. But as far as I have myself seen, there are very few characters indeed, either in the Negro or Bushman pelvis, which assimilate to those of the widely-dif- ferent pelves of the Chimpanzee or Uran. * This opinion is given by Mr. White, in his essay " On the Gradation of the Human Species," on the authority of surgeons employed in the Guinea trade ; but I am informed by Mr. Edwards, a sur- geon who has seen much of the West Indian creole negroes, that difficult labours are, on the contrary, very frequent among the females of these Creoles, who are remarkable, like the males, for the thin- ness -and narrowness of their flanks, and for the steady and easy walk which results from this formation. And he informs me also, that dystochia is not at all unfrequent even ill the African ne- From the structure of the female Bushman pelvis, given by G. Cuvier, in Hist. Nat. des Mammiferes, Dr. Vrolik draws the conclu- sion, that it presents greater animality of composition than even the Negro, as shown in the extreme vertical direction, narrow- ness, and height of the ilia, and the cylindrical form of the whole pelvis. The height of the ilia was much greater than in European females, while the width between the anterior iliac spines was less than even the smallest Negro pelvis. The spines of the ischia were, however, much wider apart, the sacrum more curved vertically, and the thinness of the iliac centres as little marked as in the Negro. The sacrum projected much forward at the base, and posteriorly was remarkable for the thick- ness and tuberosity of the lateral parts, and the posterior elevation of the coccygeal ar- ticulation, which were supposed to be for the purpose of affording attachment to the large gluteal masses of fat, characteristic of the Bushman race. The thickness, breadth, and posterior elevation of the ischial tuberosities, the posterior inclination of the cotyloid ca- vities, the prominence of the pubic symphysis, and the greater sub-pubic angle, were also remarked by Vrolik. In the pelvis of a male Bushman recently added to the Hunterian Museum, I find the iliac wings to be short, broad, not much expanded, but considerably curved antero- posteriorly ; with a crest arched, /-shaped, and reaching as high as the middle of the fourth lumbar vertebra. The centres of the iliac wings are not thicker than is propor- tional, and there is a well-formed and deep internal concavity or venter. The pectineal eminence is well marked, but the ischial spines not so, and the ischial tuberosities are small and slender. The sacrum is short, much curved vertically, and elevated in- feriorly, so as to project much behind, and diverging widely from the ischia, giving a wide and short appearance to the sacro-sciatic notch. The posterior lateral parts of the sacrum are not unusually thickened, but the sacral spinous processes are well marked and proportionally large, the two upper being very distinct, and separated from the crest. The shape of the brim is somewhat oblong and inclined to the Negro type, as may be seen from the measurements in the adjoining com- parative table. The whole pelvis has a sym- metrical, though a light, slender, and diminu- tive aspect corresponding to the diminutive stature of the individual. The breadth of the sacrum is even less than in the Negro, being exactly the same as the Uran-utan. The distance between the ischial spines is, however, greater, though that of the ischial tuberosities is less than in the Negro. The pelvi-vertebral angle in this skeleton seems to be less than usual, as far as one may venture to a conclusion from a dried skeleton. In a cast of a female Bojes- man recently added to the King's College Museum, however, the vulva seems to be placed unusually far back, which may pro- L 3 150 PELVIS. bably depend upon great obliquity of the pelvis. The measurements of the Tahitian male pelvis, given in the table, corresponds, in the proximity of the ischial spines and narrow- ness of the sacrum, with the Negro and the Bushman, though its transverse diameters, unlike the Negro, are larger than the antero- posterior. In this respect, the Bushman more nearly approaches the Negro. The great antero-posterior diameter of the cavity shows a great vertical curvature of the sacrum. In the sacro-vertebral and pelvi- vertebral angles, the Bushman and Tahitian are nearly alike. The pelvis of the female Australian, also in the Hunterian Museum, presents a very re- markable shallovvness of the true pelvis. Otherwise, it is light and roomy, with well- expanded and very short ilia. The shape of the superior opening is of a perfect oval, with the transverse diameter half an inch larger than the antero-posterior. Though a much larger pelvis than that of the Bushman, its total depth is nearly as limited, and very much more so than in European female pelves of equal horizontal diameters. In these specimens of races, considered by some to be more nearly related to the apes than the European, an examination of the adjoining table will show a ver}' great pelvic difference between them and the highest apes, in the less proportionate preponderance of the antero-posterior over the transverse dia- meters, the shortness and expansion of the ilia, the less depth of the true pelvis both in front, sides, and behind, and especially in the more marked sacro-vertebral angle. M. Vrolik describes the pelvis of the Javanese as very light in structure, of small size, and of a characteristic circular form at the superior opening, the bones being like those of a very young person, and the muscles correspondingly feeble. The small projec- tion of the sacral promontory was also re- markable, as well as the great inward projec- tion of the ischial spines, more marked, he says, than in the pelves of any other nation, and quite characteristic. By the comparative measurement of many human pelves of different races, Professor Weber reduced them to four principal forms, distinguished by the general shape of the pelvic openings. 1st. The oval form. — The superior opening of an egg-shaped figure, narrow in front, broadest near the sacro-iliac symphysis, and again narrowing to the sacral promontory. The antero-posterior diameter smaller than the transverse. The ilia moderately distant, and obliquely placed; and the convergence of the walls of the true pelvis downward, also moderate. The sacrum moderate in breadth, length, and vertical curvature. The ischial tuberosities placed rather backward, and the spines widely distant. The sub- pubic angle neither very acute in the male, nor the arch very prominent in the female. Of this type, he makes two varieties, — viz. the oval or male-oval, and the round-oval or female-oval; the male variety of form being sometimes found in the female. Of this form he gives three specimens : — one of an Euro- pean male; one, very large, of a Botocundo male; and one of the round or cross-oval form, in an European female pelvis, broad and shallow, with the transverse diameter 5 in., and the conjugate 3 in. 10 lines. The pelvis of the Australian female, given in the table, belongs to the round-oval form, and that of the male Tahitian to the male-oval form. 2nd, The round form, distinguished by the round or cross-formed superior opening, by the vertical sides, less anterior direction of pubes, and less projection of sacral pro- montory, making the conjugate of nearly the same extent as the transverse diameter.* Of this form he gives five specimens, all females : — one European, two Negresses, one Hot- tentot, and one Javanese. 3rd. The square or four-sided form, dis- tinguished by the great breadth of sacrum and horizontal flattening of pubes. The transverse diameter greater than the conju- gate, but the superior opening forming nearly a square. Of this form are six specimens : — one of an European female ; two of Javanese male, and one of a female of the same race, and two Mestizos. 4th. The cuneiform, or oblong form. — Su- perior opening laterally compressed and ob- long ; sacrum very narrow ; pubis with great anterior direction, so as to unite at an acute angle; with the conjugate greater than the transverse diameter. In the female, this form makes some approach to the oval shape. Of this form he gives eight specimens : — one of an European female, which has this shape very well marked, the conjugate diameter being 4 in. 9 lines ; one of a female Boto- cundo ; one of a Negress ; one of a Negro ; one of a Kaffir ; and three others from Von Soemmerring's collection. The pelves of the Bushman and Negro, given in the table, belong to this form. M. Weber's conclusions drawn from these specimens are, that though the oval shape is most common in Europeans, the round shape in the American aborigines, the square shape in the Asiatic or Mongolian races, and the oblong in the Negro races ; yet that none of the characters laid down by Vrolik are con- stant, nor belong exclusively to any particular race, but that deviations from the usual form in any race present characteristics which gene- rally belong to other varieties of the human species. The coincidence between the prevailing form of the skull and that of the pelvic brim in these classes of the human race is worthy of especial remark, and influences ma- terially, as before mentioned, the adaptation of the foetal skull to the pelvic passage during labour. After the form of the skull, that of the pelvis is perhaps the most characteristic of race of any in the body, because of its great influence upon the shape of the trunk ; and yet, from Weber's researches, it would appear PELVIS, lol that it is not sufficiently so to constitute a tablish separate generic classifications of the greater distinction than that of variety, and is human species. not exclusive enough in its peculiarities to es- In the Simice, and those even which most COMPARATIVE PELVIC DIMENSIONS. ' I •f I c i (Female). impanzce nalc). i Museum.) if ran-Utan. n Museum.) I|J JC * 1 I i .2 "ft m J3 D.2 h fc 1 3 H 1 m "a ^1 e Diameters. In. Lines. In. Lines In. Lines In. Lines In. Lines In. Lines. In. Lines In. Lines Of brim — Transverse 3 9 4 6 3 6 5 0 4 0 3 3 3 9 2 3 Oblique - 4 3 4 3 3 8 5 0 5 3 4 9 4 9 Antero-posterior 4 1 4 0 3 3 4 6 5 9 5 6 5 0 4 4£ Of cavity — Antero-posterior 4 9 4 9 3 10 4 9 5 0 3 0 4 0 Of inferior outlet — Transverse (inter-sciatic)- - 3 3 4 0 3 2 4 6 3 9 4 0 2 9 3 0 Antero-posterior 3 0 3 3 3 5 4 0 4 6 3 6 4 0 Between anterior superior iliac 8 fi 8 6 7 3 8 3 10 0 5 6 LI O 4 0 Depth of true Pelvis. o o 11 \j Between sacral promontory and tip of coccyx .... - 5 6 4 0 4 6 5 0 4 6 4 6 Between ilio-pectineal eminence and sciatic tuberosity 4 3 3 9 3 6 2 10 4 10 3 6 4 0 Between upper and lower border of symphysis pubis Depth of whole Pelvis. 1 9 1 6 1 3 1 3 2 6 1 10 2 0 Between iliac crest and sciatic tuber : _ 8 0 7 0 7 6 10 9 9 0 9 6 5 4£ Between tuber ischii and anterior superior iliac spine _ 6 6 5 6 6 0 9 6 8 0 8 0 Between tuber ischii and posterior superior iliac spine - 6 3 5 6 6 0 10 0 9 0 8 6 Between ischial spines 3 0 3 3 3 3 4 3 3 9 3 2 3 0 Breadth of sacrum - 3 9 3 9 3 3 4 6 3 0 2 3 3 3 Angles — Sacro-vertebral - _ 120° 115° 135° 158° 145° 150° Pel vi- vertebral - - 145° 145° 140° Sub-pubic - - 60° 85° 90° 80° 60° 50° closely approach in osseous conformation the human race, as in the genera Pithecus and Troglodytes, the form of the pelvis is suffi- cient, at a glance, to distinguish them even from the Bushman and Australian, which have been seen to present all the pelvic pecu- liarities of the higher varieties of humanity. An inspection of the foregoing table will at once show this in the pelvic diameters. It will be seen that the antero-posterior dia- meters in the Chimpanzee, Uran-utan, and Gibbon prevail greatly over the transverse ; that the depth both of 'the whole and the true pelvis is much greater than in the human pelvis ; and that the sacrum is much narrower, espe- cially in the Chimpanzee, and the ischial spines more closely approximated. The, sacro-ver- tebral angle, too, is remarkably increased, es- pecially in the Chimpanzee (160°), the sacrum being placed much more nearly in the direc- tion of the whole spinal column, and having a less vertical, as well as a much less horizontal curvature, with no sacral promontory in the Chimpanzee, and little in the Uran ; while the coccyx is straighter, and placed more in the line of the spinal column, and its tip is ele- vated above the level of the upper border of the symphysis pubis, so that the whole of the sacrum and coccyx is seen in front view. (See fig. 92.) This high position of the coccyx is owing partly to the shortness of the sacrum, which is composed of three large flat vertebrae, all entering" into the formation of the sacro-iliac joint, and united by ankylosis to two of the four coccygeal pieces in the Uran, and to one only in the Gibbons. In the Chimpanzee, however, there are four sacral vertebrae, all articulating laterally with the ilia, and the anterior sacral foramina are very small. The coccyx is composed of five vertebrae. The ilia are much longer, thicker, more massive, and narrower, and present no central transparent portion nor internal fossa, being flat anteriorly and concave posteriorly, the re- verse of the human ilia, and looking almost directly backwards and forwards, and very little inwards and upwards ; so that, in these animals, there cannot be said to be any false pelvic cavity. In the Uran of the Hunterian Mu- seum they are two thirds of the femurs in length, and measure 6 inches, and in the Chimpanzee 7 inches, reaching as high as the third lumbar vertebra. From the limited expansion of the L 4 152 PELVIS. wings, the anterior part seems deficient, the anterior superior spine (a) being placed directly over the cotyloid cavity ; and the crest (c) being, consequently, very short, terminating abruptly at the vertical rib mentioned in the description of the human ilium. The alts are more expanded in the Uran than the Chimpanzee. The crest does not present the lateral /-like curvature, and is less arched than in man. The anterior iliac spines are more widely separated, the inferior (6) being scarcely discernible, and the border between them thin and concave. The posterior, or iliac tuberosity is even less prominent in these animals than in the lower order of Ruminants. The distance from the cotyloid to the sacro- iliac joint is 3^ inches in the Hunterian Chim- panzee, and about 3 inches in the Uran, though, from the greater straightness and obliquity of the cotylo-sacral arch (d) and the want of the anterior curve, the direct horizontal distance between these points is about the same as in man. In the Simice generally, the ilia are said to be placed almost in a straight line with the spinal column. Added to the great length of the ilia, this arrangement causes the pelvic brim to be much elongated from before back- wards ; but much less so, however, than it would be if the pubes and iliac shafts were in the same plane. I have, however, found the ilio-vertebral angle in Chimpanzee, Uran, long- armed Gibbon, and brown Baboon to be very little, if at all greater than the human pelvi- vertebraly as far as could be ascertained without actual section of the bones. But in the Lemurs the ilia are only 10° from being in the same straight line with the spine ; while in the Man- drill and many Monkeys they are almost pa- rallel. This characteristic, heightened by that of the much diminished curve of the lumbar vertebra and the elongation of the iliac shafts in these animals, contributes to form a great Fig. 92. Pelvis of the adult Chimpanzee, anterior view. contrast with those of the human pelvis. In the Uran, a projection of the sacro-iliac joint in front is observable, and a solidity of the shafts of the ilia. Blainville remarks, that the sacro- iliac facet is oval in these animals. The ischia, in common with the whole pelvis, are longer in the Chimpanzee than in the Uran ; and the ischial tuberosities (e) more turned outwards. In both, however, they are directed much more in the line of the ilia than in the human species, the ilio -ischial angle being 165° ; and are larger, more flattened, spread, and diverging. The ischial spines in these animals begin to degenerate, and are rather rounded eminences or ridges than true spines; and the inferior rami (/) are directed almost horizontally inwards, leaving a large triangular foramen obturatorium, and entering into the formation of the pubic symphysis (g), which in the Sonus generally, may be more properly called the ischio-pubic symphysis. The whole of the ischial portion of the pelvis has a more anterior position, and a more laterally flattened appearance than in the human pelvis. The cotyloid cavities are small, elongated ver- tically, and deeper behind than above. The sciatic notches are long and narrow. One of the most remarkable differences from the human pelvis, however, is the difference of direction of the ilia and pubes with regard to the transverse-vertical plane of the spinal column, an arrangement which bends the plane of the pelvic brim at the ilio-pectineal eminence in different directions. In the Chimpanzee, the antero- posterior angle y formed by the su- perior ramus of the pubis with the cotylo- sacral arch of the ilium, is 120°, and in the Uran 125° ; constituting a striking difference from the human pelvis, where the cotylo-sacral and pubic arches are in one plane. This alteration in the direction of the pubis will be found to be a great characteristic of all quadrupeds, in the prone position of whose bodies the pubis has a tendency to be placed more vertical and more anterior, to be out of the way of the femurs in their angular movements. In the Sloths and Anteaters, the pubis will be seen to be turned in the opposite direction, yet still forming an angle with the ilium, but with the retiring sides turned backwards. I think, therefore, we may safely take the ilio-pubic angle as a general peculiarity of the inferior animals possessing pelves, and one which distinguishes them, as far as I hare seen, universally, from the human species (see page 173./g. 112.2—13.). A remarkable consequence of this more horizontal direction of thejpubis in the Simus is the disappearance of the angle of the symphysis, it being quite parallel with the spinal column. And this parallel position is, according to Cu- vier, a mark of distinction between all the brute creation and man. In other respects, the pubis of the Simice is short, little arched, and without marked spine. The inferior outlet of the pelvis is larger than it would otherwise be, from the elevation of the coccyx, and, from the shortness of the sacrum, and length of the ischio-pubic symphysis, its plane is more parallel, and its axis more in a line with those of the brim than in man. So we see, in these animals, a marked and PELVIS. 153 evident degeneracy of pelvic structure, allying them much more closely to the quadrupeds, especially to the Carnivora, than to mankind. And we may remark, more especially, that their fitness for the habitual erect position is much diminished by the want of direct antero-pos- terior extension of the pelvis, produced by the flatness of the sacrum and the lesy marked sacro-vertebral angle, and the shortness and change of direction of the pubis; which renders the arms of the pelvic lever shorter from the cotyloid fulcrum, and the hold of the extensor and flexor muscles of the thigh less powerful in maintaining the standing posture. And, cor- responding to this, we see in these animals, great diminution in the bulk of these muscles, particular!} in the glutei and gastrocnemii, the plumpness of which constitute the buttocks and calves characteristic of the human figure From this cause, the gait of these animals in bipedal progression is very unsteady. The expanded, everted, and large ischial tuberosities, and the strength of the ischio- sacral arch, indicate that the sitting posture is more natural to the Simial race ; while the greater depth of the posterior than the supe- rior part of the cotyloid brim shows, as well as the marked ilio-pubic angle, a provision for femoral support in a semiflexed, rather than an extended position. In the erect posture, from the flatness of the pelvis, the ischial tuberosi- ties are brought close upon the femurs, and reach nearly half-way down their short shafts, interfering much with their motion. According to Grant and Wagner, there is no cotyloid notch nor ligamentum teres in the Orangs; but the cotyloid notch is present, though small, in the skeletons I have examined. In the Hylobatis Lar^ or long-armed Gibbon, the iliac wings are flatter, and directed still more antero-posteriorly, crest rounded, large, and elevated ; ischia short, in a right line with the ilia, with flattened and expanded tube- rosities, spines more distinctly marked, and rami directed, like the elongated pubes, more directly inwards. The cotyloid cavities are thus more widely separated, and the superior pelvic outlet has a triangular form, with the small end directed backwards. The sacrum is narrow and flat, forming a large angle with the spine, and composed of five vertebrae, of which the three upper, considered by Blainville to be the only true sacral vertebrae, articulate with the ilia. The coccyx, consisting, ac- cording to Blainville, of seven, according to others, of five vertebrae, is short, there being no tail. The inferior outlet is large, and the true pelvis shallow, from the shortness and expansion of ischia. The subgenera CUKtibir, Cercocebus, and Semnopithecus present an elongation of the coccyx into a caudal appendage with prehensile attributes, and perforated for the continuation of the spinal cord, which widens still more the progressive separation from the human type. In the Squirrel Monkey are three sacral bones, of which the two upper articulate with the ilia, and the broad transverse processes of the last project towards the ischia, so as to give a square outline to the inferior outlet. Ischial tuberosities not flattened. In the Capuchin Monkey the ilia are parallel with the spine, the ischia are inclined forwards to the abdominal surface, and the pubes are more oblique. In the Semnopithecus entellus the sacrum is more arched laterally and broader. The ilia are prismatic and" long, and project more behind the spinal column. The ischia and pubes are short, with flattened and expanded tuberosities, and no ischial spine. Ilio-pectineal eminence marked. In these tribes the posterior border of the elongated ilia is the thickest part of the bone, the anterior part being thinned and spread out more or less. The pubes are generally placed nearly at right angles to the ilia, and the lumbo-iliac angle is about 160°. Of the genus Cercopithecus, or Baboon tribe, there is, in the brown Baboon, a well marked sacro-vertebral angle (155°); the two upper of the three sacral vertebrae only articulate with the ilia. The caudal vertebrae are not numerous. The ilia are more expanded, but still present the posterior concavity. The ischia are short, with very broad and flattened tuberosities. The pubes are flattened, with an acute superior border, and rostrated at the symphysis. Ilio-pubic angle more marked ( 1 10°). In the Mandrill, Papio Mammon, the sacrum is more arched both vertically and transversely, and the promontory better marked. The coccygeal vertebrae are four in number, and there is no tail. The ilia are parallel with the spine, directly under which are placed the co- tyloid cavities. The ischia are short, with much-expanded and flat tubers. The pubes are at right angles, both to ilia and spine, and the ischio-pubic symphysis is very little ad- vanced before the plane of the spinal column. In the Sapajous, or American Monkeys, there are three sacral vertebrae, of which the first only articulates with the ilia in the Onistiti. In the White-bellied Ateles the ilia are longer and more expanded ; pubes more oblique ; ischia short, with no spine, and small tuberosities. In the Saimiri there is a very short ilio-ischium. In the Lemurs, or Makis, the sacrum is in a right line with the spine. Of the three sacral vertebrae, the first only articulates with the ilia, and the last is not ossified to the second. They differ little from the lumbar vertebrae, except in the thicker transverse processes. Caudal vertebrae numerous. The pelvis generally is very weak, narrow, and short. The Uia are narrow and almost pa- rallel with the spine, and the ilio-pectineal eminence is unusually well marked ; but the ischial tuberosities are delicate, indicating the less frequent sitting posture in these animals, and a still greater tendency to quadruped pro- gression. In the Lemur albifrons, however, the sacrum is broader ; ilia more expanded ; ischial tuberosities larger and more expanded; ilio-pubic angle 120°. In L. tardigradus the sacrum is long, narrow, and keeled in the middle, being ankylosed to the last lumbar and three first coccygeal vertebrae, as in birds. 154 PELVIS. The ilia are narrow and cylindrical; pubes long, large, oblique, with no ilio-pectineal apo- physis ; ischia short, with horizontal raini and tuberosities passing backward to articulate with the transverse processes of the upper coccygeal vertebrae, another bird-like arrange- ment. In L.indri the sacral pieces are four, with complete ankylosis, the two or three upper articulating with the ilia. Ilia expanded, with extended crest and external fossa, and reaching to the penultimate lumbar vertebras ; ischia very short, with more expanded tubers ; pubes less oblique. In L. volans, or Galco- pithecus, the sacrum has five vertebrae, the first only articulating with ilia. Ilia small and narrow ; ischia with large posterior angle; pubic symphysis very short. In the sub- genus Sterops, the slender Loris presents a remarkably elongated and contracted pelvis. The sacrum is long and narrow, with the two upper pieces articulating with ilia. Ilia slender, long and columnar, and nearly parallel with spinal column ; ischia small, flattened laterally, placed in a line with the ilia, and very near each other, so that the cotyloid cavities are closely approximated ; the lateral diameters very short, Fig. 93. and the inferior outlet a mere chink. The pubes are long, projecting forwards, down- wards, and inwards, being in- clined to each other at an angle of 40°, causing the superior outlet to be trian- gular, with the base at the inter" cotyloid diameter, and the apex at the symphysis pubis. This pelvis is also remark- able for the extreme angularity of the pubic portion with the iliac, the ilio-pubic angle being 75°, or less than aright angle, the only instance of the kind I have met with. (See fig. 93. a, b, sacral vertebra?, articulating with the ilia, their transverse processes being long and coalesced, but the spinous processes distinct. In the Potoroo there is one only, with large lateral processes. The caudal vertebrae are numerous and very strong, and their upper normal spines encroach much on the diameter of the pelvic cavity and posterior outlet. The ilia have short, strong, and pris- matic shafts as in the Rodents, with alae of the same shape, much elongated and turned out- wards, though in a much less degree than in the Wombat, and terminating in narrow clubbed crests (jig. 99. g). There is a rudimentary inferior anterior spine (/*). The upper part of the iliac wing projects much on the dorsal aspect of the spinal column, forming with it an angle of 140° (see fig. 112. 9.). The ischia are very long, broad, and strong, and have much-expanded tuberosities with an outward curvature (fig. 99. e). These are united in a median symphysis by a single V-shaped epi- physis (c), divided, in the adult, by a suture from the ischia. The tuberosities support also another epiphysis on each side posteriorly at e, the anterior ischial rami being almost deficient. The ilia and ischia are very nearly in a direct line. The pubes are moderately long, slender, and directed much downward, so as to give to the anterior outlet a triangular shape, with the base at the broad sacrum, and the apex at the pubic symphysis. The ilio-pubic angle is 135°. The marsupial bones (ay b ) are smaller, rounder, and more curved externally than in the Wombat. Their free extremities are tuber- culated and not flattened, and they are articu- lated to the pubic crest near the symphysis by a single facet only, the inner, the position of the outer one being marked by a slight tubercle (6). The ilio-pectineal spines (d) are very large, for the attachment of powerful psoae muscles. The direction of the ischio-pubic symphysis PELVIS. 161 (/) in the Kangaroo, Phascogale, and Potoroo, is not parallel with the spinal column, but Fig. 99. Pelvis of the Kangaroo, showing the marsupial bones (a a) and inter-sciatic epiphysls (c). oblique in the opposite direction to the human symphysis, so that if prolonged forwards the line of direction would cut the spinal column at an obtuse angle. This makes the posterior opening larger in its antero-posterior diameter than it otherwise would be, and allows for the great encroachment of the caudal ver- tebrae posteriorly. The sciatic notch is long and narrow, corresponding to the great length of the ischia ; and the foramen obturatorium is large and elongated antero-posteriorly from the same cause. In the Dasyurus and Pe- taurists, the ischio-pubic symphysis is oblique in the opposite direction. The antero-pos- terior diameter of the anterior outlet in the Kangaroo is greater than the transverse by about half an inch ; but at the posterior outlet, the transverse is a little greater, from the pro- jection of the caudal spines before mentioned. The pelvic cavity is deep in the Marsupialia, and its. openings are small in proportion to the size of the animal, since the foetus is expelled before it is full grown, and placed on the nipples in the marsupial pouch to complete its deve- lopment into a state of independent existence. But the proportion between the pelvic open- ings and the size of the foetal head, at the period of expulsion, is very remote. Even in the PetauristSy whose pelves are the smallest, the cavity and openings are six times the size of the foetal head. The muscles of the tail and legs attached to the pelvis are, in the Kangaroos, very powerful to perform their prodigious leaps, especially the gracilis and biceps. The glutei, however, are not large, since the trunk is not held erect on the legs by these muscles, but is suspended, as it were, between the femurs, and supported in front by the largely developed psoas muscles, and behind by the powerful tail, used as a propelling organ by the sudden action of its flexor muscles. The pelvis of the Monotremata resembles in general appearance the reptile type, although Snjyp. in some other respects these curious animals, especially the Ornithorhyncus, approach the Birds. The sacrum of the Ornithorhyncus is composed of two vertebras, separated, as in the Saurian reptiles, and placed in the line of the lumbar curve, differing little in appearance from the lumbar vertebrae. In the Echidna are three sacral vertebrae, also separated and all uniting with the ilia. The ilia are short, thick, and prismatic, and project above the spine at an angle of 140° as high as the sacral spines, and presenting, in the Ornithorhyncus, considerable eversion of the alae, and, in a much less degree, in the Echidna also. The ischia are short, bent upwards in the former, and project backwards at the tuberosi- ties in an angular spine, most marked in the Ornithorhyncus, and giving a reptile-like ap- pearance. The pubes are broad and short, placed at a marked angle with the ilia, 1 10° in the Echidna hystrix and 120° in the Ornitho- rhyncus, and uniting by broad plate-like rami with the ischial rami, which form with them a long ischio-pubic symphysis. The ischio- pubic plate thus formed is very like that seen in the reptiles. The marsupial bones are also present, and are very large and strong in this class, although not provided with a pouch. In the Ornitho- rhyncus they are broad and triangular, articu- lated by the base to the whole length of the pubic crest meeting in the median line, and with their rounded apices directed forwards and outwards. In the Echidna they are longer, rounder, more pointed and less everted, with two articular processes at the pubic extremity (see fig. 177. Art. Manofremata). The ilio-pectineal spines are also very large in the Ornithorhyncus, and in a less degree in the Echidna. The obturator foramina are small. The three pelvic bones are united at the cotyloids by bony union in the Ornithorhyncus. In the Echidna hystrix, the union of these bones is, however, effected by cartilage only, and the acetabula are perforated by a consider- able opening into the pelvic cavity, constituting another remarkable reptile-like peculiarity. Having traced the Mammalian pelvis to a form presenting somewhat of the reptile type in the Monotremes, we may now recur back to an order of animals which, from their general organisation, are connected closely to the order of primates, and are usually placed much higher in the animal scale than the position here assigned to them. These are the Sloths or Tardigrades, which form the connecting link between theSimife and Edentata proper. Their pelvic peculiarities, however, ally them more closely to the Birds. The moststriking of these is the ossification of the ilia and ischia to the broad sacrum, by transformation of the sacro-iliac and sacro- sciatic ligaments. We have already noticed tin exceptional example of this coalescence in the Ruminants, in the Meminna or pigmy Chevrotain. But the pelvis of the Edentata also presents a diminution of the pubic sym- physis, and the absence of the ischia from this junction, a separation which is carried M 162 PELVIS. still further in the Insectivora and Cheiroptera. The increasing obliquity of the pubes also indicates an approach to the Bird type. The climbing habits of the Sloths produce a habitual vertical position of the trunk, re- quiring for the support of the abdominal viscera large open pelves. In the Ai {Bradyptu tridactylus) the pelvis {fig. 100.) is remarkably slender, expanded, shallow and horizontal in direction, the pelvic openings being very large and round, and the antero-posterior diameters little larger than the transverse. The ankylosis of the innominate bones to the sacrum in these animals gives a great firmness to the support of the otherwise feeble hinder extremities, and with the great distance of separation of the acetabula, which are small and shallow, assists to a considerable degree their climbing and holding powers, and to produce that slowness and awkwardness of motion which has given them the name of Tardigrades. Fig. 100. Pelvis of the Ai, anterior view. The sacrum is large, both in length and breadth, very flat, with large, open foramina, and presenting a flattened surface in place of the posterior spines and tuberosities. It is composed of five vertebrae, of which the three upper (e) as well as the last lumbar (g) are ankylosed to the ilia (&). The union of the last lumbar seems to result from an extension of ossification in the ilio-lumbar ligament (0, and contributes much to increase the steadiness of the spinal column on the pelvis. The coccyx is triangular, little curved, broad and short, and is composed of six pieces. In some species it is prolonged into a tail* The ilia are short and slender, with much- expanded wings, having an anterior concavity and a plane surface posteriorly. They are ossified to the sacrum at an early period. The ischia are short and slender, and united to the last sacral vertebra, and more slightly to the two above it, by ossification of the great sacro- sciatic ligament («), which gives to the angle of the bone an expanded appear- ance, and encloses a round, wide sacro-sciatic foramen (d), above and behind the cotyloid cavity. The tuberosities are small, and the inferior rami (/) are long and slender, enclosing with the pubis a very large obturator foramen, having its long diameter from side to side, and do not join in symphysis. The pubes (//) are long and slender, their rami united in a V shape, with the angles meeting to form a very short symphysis (c), which is sometimes ossified, and presenting a very slight ilio-pectineal spine (i). The lumbo-Hiac angle in the adult Bradypus is about 145°, and the ilio-pubic about 155°, being only about 25° from a right line as in the human pelvis. The ilio-ischial angle also approaches the human standard in being di- minished to 135°. This diminution of the ilio-ischial angle is still more remarkably shown in the My- lodon and Megatherium fossil gigantic Sloths, which approach more closely to Man in this respect than any other Mammalian. The osseous system of the fossil Mytodon robustus closely resembles that of the Sloths, differing from thenr, however, by presenting a continued sacral crest, and more expanded ilia {fig. 101.). According to Professor Owen, in his valuable monograph on the specimen in the Hunterian Museum, the sacrum really con- sists of seven vertebras, but by ankylosis with the three lumbar and last dorsal includes eleven vertebrae, and forms one strong and con- tinuous bony mass along the whole lumbar re- gion (a). Its total length is 2 feet 4 inches, and it gradually increases in breadth to the sacro-iliac union (. 108. a.} are short, thick, curved roundish and clubbed inferiorly, and are di- rected outwards, forwards, and downwards, extending under the back plate directly be- tween the sacrum (at i) and the acetabula. In the Tortoise and Trionyx they are moveable upon the sacrum forwards and backwards. From the acetabula, the ischia (c), larger than the ilia, pass, almost at a right angle, backwards and inwards, and unite in a median symphysis (rf), forming the real pelvic circle, and present- ing a sharp angle posteriorly in the Trionyx (/) and fresh-water Turtle. In the land and fresh- water Tortoise this symphysis is continu- ous anteriorly with the inter-pubic (e), forming with it a cross-shaped suture, and the ob- turator foramen on each side is distinct and separate ; but, in the Turtle and Trionyx, as in most reptiles, the inter-pubic and inter- ischi- atic symphyses are separated and connected by cartilage only, and thus, in the dry bones, the obturator foramina are coalesced in one large opening, and the pubes and ischia have the appearance of large ribs connected at their ventral extremities. The pubes (A) are the Fig. 108. 9f Pelvis of the Trionyx, or Mud Tortoise, superior view. largest of the bones in the reptile pelvis, and, as seen in the Turtle, pass each from the acetabula as a thick bone, which expands as it passes downwards into a broad plate, and divides into an inner portion which unites with its opposite fellow in a symphysis (e, e'} and an outer portion, free and directed ex- ternally (h). In the Chelydes all the pelvic bones are ankylosed to the plastrum or to the back-plate ; but in the others, the ischia and pubes are connected to the plastrum by liga- ments only. The anterior pelvic opening in the Chelonia is directed upwards and forwards. The pelvis of the fossil Plesiosaurus is very like that of the Tortoise, with narrow, small, and weak ilia, with the fan-like, spreading ischia, and large square pubes uniting in a common symphysis, by a crucial suture. The pelvic and shoulder bones have a great resemblance in the Chelonian as well as in the Saurian reptiles. Of the Saurian reptiles the Crocodiles have two sacral vertebras with large spines (Jig. 109. a, a'), which support the ilia by strong prismatic apophyses, ankylosed together at the ends, and separated by a suture, in the young animals, from the bodies of their vertebras. The caudal bones in all the Saurians, are very numerous. The ilia (b) are very short, and in some species almost cuboid', slightly bent, with an inward concavity, and directed downwards and a little forwards, but almost at right angles to the spine, with the superior angle (e) projecting backwards. The ischia (c) are long, and directed, like the sides of an PELVIS. 171 isosceles triangle, downwards and inwards, uniting in a median symphysis (/), and much resemble the coracoid bones of the shoulder. The acetabula of the crocodile look di- rectly outwards, have strong inter-articular ligaments, and are formed only by the ilia and ischia, the latter presenting, just below the acetabulum, anterior apophyses which support the pubes. The pubes (d) are directed much forwards, downwards, and towards each other, but do not touch in the median line, being united only by the abdominal aponeu- Fig. 109. n Pelvis of the Gangetic Crocodile (side view). rosis (A). They are connected by the anterior border with the posterior abdominal ribs (g). The Lizards have, like the crocodiles, two sacral bones, as in the Iguana and Great Monitor. In many Lizards the sacral trans- verse processes (fig. 110. A, a) are very long, and, being articulated by suture to the bodies of the vertebrae, appear, at first sight, like additional ilia. This is particularly the case in a fossil specimen recently dis- covered by Sir Charles Lyell.* The ilia (b) are directed forwards and downwards, and the su- perior extremity projects backwards in a trun- cated point ( ilio-ischial angle reversed. 6. Pachyderm type. 7-. Ruminant type. 8. Rodent type, no ilio-ischial angle. 9. Kangaroo type. 10. Bird type, no "ilio-ischial angle. 11. Raptores type, ilio- ischial angle reversed. 12. Chelonian type. 13. Saurian type, ilio-pubic angle reversed, and remarkably acute ilio-ischial angle. 174- PELVIS. TABLE OF COMPARATIVE PELVIC ANGLES. {! Is Sj Sacro- vcrtebral. 1. Man ... Decree, Degrees. 0 Degrees. 110 Deg. 117 2. Orang ... 160 125 165 150 3. Chimpanzee - 155 120 do. 160 4. Gibbon - do. 130 0 170 5. Baboon (brown) do. 110 0 155 (160 90) 6. Monkeys - to to 0 0 [170 120) 7. Lemur (albifrons) - 170 120 0 0 8. Loris gracilis - do. 75 0 0 9. Sloth (Ai) - 145 155 135 0 10. Mylodon (fossil) 125 155 120 160 eversed 11. Megatherium (ditto) do. 125 — eversed 12. Armadillo 155 150 145 0 13. Ant-eaters 140 155 do. 0 eversed 14. Lion 150 120 0 170 15. Tiger 160 110 165 do. •eversed 6. Leopard - 150 120 0 do. 7. Hyaena - 140 125 0 160 8. Bear (brown) - do. do. 0 do. 9. Badger - do. 130 0 170 20. Racoon - 150 145 160 0 21. Elephant » 120 100 145 170 22. Rhinoceros 125 150 do. do. 23. Hippopotamus IfiO 125 170 160 '24. Hog ... 145 120 do. do. 25. Tapir ... 125 145 140 0 26. Horse ... 130 130 145 0 27. Ox tribe - (145 i I to }• 130 130 150 (150) 28. Deer tribe 150 140 150 160 29. Irish deer (fossil) - 145 135 do. do. 30. Giraffe - - - 150 140 145 170 31. Camel ... 140 120 155 155 32. Sheep and goats 33. Rats and mice 145 170 130 150 150 0 170 0 34- Hare 165 120 0 160 35. Jerboa ... 140 145 0 0 36. Kangaroo do. 135 170 0 37. Wombat - 160 130 do. 0 38. Thylacinus (cyno- ceph) 150 115 do. 0 39. Ornithorhyncus 140 120 155 0 tO. Echidna (hystrix) - do. 110 0 0 41. Hedgehog 130 150 0 0 42. Bat (Ternate) 0 100 0 0 (150 155) 43. Birds, generally \ to (160 to [ 160) 0 0 44. Ostrich ... 160 155 0 0 45. Uhea - do. 140 0 0 46. Cassowary do. 155 0 0 47. Apteryx - 155 140 140 0 reversed 48. Eagle ... 150 195 130 0 reverset 49. Owl - - - do. 140 14.7 0 reversed ( 80 50. Chelonian reptiles - 1 to 130 80 0 (100 ( 60 51. Crocodiles ] to 140 130 0 ( 90 52. Lizards (Monitor) - ( 40 \ to ( 90 j 160 reversed 60 0 Having thus taken a general review of the progressive development of the pelvis, and traced it from its most perfect form in man to its most rudimentary elements in the fishes; we can enter more prepared into the consi- deration of the serial homologics of the pelvis and its ligaments. SERIAL HOMOLOGIES OF THE PELVIC BONES AND LIGAMENTS. The sacrum, according to Professor Owen, is to be considered as the centrum of the pelvic vertebral elements. The ankylosed bodies of the sacral vertebrae, as well as their coalesced laminae, spinous and articular processes, are sufficiently evident as the representatives of those components of the neural arch in the typical vertebra.* The lateral masses of the sacrum which support the ilia are, however, made up of two elements coalesced together, as is shown in the manner of their develop- ment, before described, viz., first, of the true transverse processes, or " diapophyset" con- stituting the external row of tubercles seen on the posterior surface of the sacrum, and which are ossified, like those of the true vertebrae, by extension from the same points of ossification as the laminae, and spinous and articular pro- cesses ; and, secondly, of the six characteristic sacral ossific points, three on each side of the three upper sacral bodies, which are placed on the anterior surface of and below the former, between the sacral foramina, as before de- scribed. These ossific points, as shown in prepara- tions exhibited to the British Association, in 1837, by Mr. Carlyle, were four in number on each side, and very distinct from the true transverse processes ; and they were con- sidered by him to represent the necks and heads of four sacral ribs on each side. Upon the truncated extremities of these three or four sacral ribs the auricular facets are sup- ported. They appear to be similar to the anterior roots of the cervical transverse pro- cesses, upon the last of which is occasionally developed, in the human subject, a short costal process. In the nomenclature of Professor Owen, they may be considered the sacral " pa- rapophyses" but differ from these processes as seen in the rib-bearing vertebrae of the Croco- dile, in being developed by separate and distinct centres. Blainville remarks that the four upper sacral vertebras, scientifically considered, com- pose the whole of the true sacral elements ; and that the fifth, which he calls " subsacral" is an ankylosed coccygeal vertebra. But the lateral epiphysial plates of bone before described — • the upper of which forms the auricular facet, opposite the three first, and the lower, the sides of the two last sacral vertebrae — would seem to connect these vertebrae more particu- larly together, and to be the coales< <;d serial homologues of the epiphyses forming the ar- ticular facets on the tubercles of the ribs. In the Saurian reptiles these sacral ribs, two in number on each side, are very distinctly analysed, and have been before mentioned as intervening between the sacrum and the ilia. The anterior of these ribs in the Saurians are said by Mr. Carlyle, to be articulated to the bodies of the last dorsal and first sacral ver- tebrae, as well as to the intervertebral sub- stance between them'; and the posterior, to the last sacral and first caudal vertebrae, and to their intervertebral substance — affording an exact homologue to the true ribs. The ilia in the human fcetus, and for some years after birth, are connected to two only of the sacral vertebrae ; but, in the adult state, they * A remarkable analogous instance of the coales- cence of vertebrae to form one solid mass is seen in those of the cervical region of the bottle-nosed Whale. PELVIS. 175 join three sacral ribs, corresponding, as we have seen, to the three upper sacral vertebrae. Mr. Carls le has seen them, in the negro, join four sacral ribs, as above stated. The sacral element of the pelvis we have found to be most largely developed in, Man, and its angle with the spinal column most marked, in adaptation to his destiny for the erect and bipedal posture. In Birds, also, of bipedal and semi- erect position of body, it is also large, and, in a less degree, in animals whose climbing or sedentary habits require an habitual upright direction of the vertebral column, such as the Apes, Bears, and Sloths ; while it is much contracted, both in breadth and length, in most of the animals of true quadrupedal progression. Its spinous pro- cesses arc long, and sometimes united in a crest, in the springing animals, and those re- quiring long leverage for the muscles of the back and thigh arising therefrom. The coccygeal pieces are, in the human subject and the higher Simue, the aborted continuations of the sacral vertebrae, gradually diminishing into their most permanent and principal elements, — the bodies of the ver- tebrae. The upper ones show also rudimen- tary transverse processes, and the first pre- sents well marked articular processes to join with those of the sacrum, or sacral horns. Dr. Knox considers the 1st coccygeal ver- tebra to be the representative, in man, of a class of vertebra? distinct both from the sacral and remaining coccygeal. In Man these bones are placed very obliquely, to support the pelvic viscera ; but in the lower mammals, the Birds, and especially the Reptiles and Fishes, they are placed in the line of the vertebral column, and are developed as caudal vertebrae, in adaptation for their various uses in propulsion or prehension, &c. In many, they present not only a complete neural arch and spine, enclosing the caudal continuation of the spinal chord, but also an anterior or hcemal arch and spine, to enclose .and protect the arteries of the tail. The ilia evidently consist of the shafts of the three or four sacral ribs, coalesced into one mass of bone on each side, and constitute the homologues of the shafts of the thoracic ribs, termed by Owen the " pleitrapophyses." The descending branch or body of the ischium is considered by the same writer also to form one of these plenrapophyses. The develop- ment of the whole of the iscJihim, as well as the pubis, from a single and separate centre ; and the connection of both these bones to the ilium in the cotyloid cavity, seems, however, to place the whole of each bone in the same relative position, and to class them both with the chondro-sternal elements, or " hcemapo- physcs *' of the thoracic ribs. Professor Owen considers that the pubes and the ascend- ing rarai only of the ischia are the homo- logues of the rib cartilages, — an arrangement that would make a separation of the ischium, which its mode of development from a single centre would hardly justify. The bent and hook-like form of the Mammalian ischia finds a very close counterpart in the cartilages of the eighth ribs, in Man, especially when these are ossified, as often occurs ; and the manner of its junction with the pubes in the human subject is exactly similar to that of the eighth cartilage with the seventh, before it reached the sternum. In many of the lower Mam- malia, especially in the Marsupials and in the Reptiles, we have seen that the ischial ribs reach each other, and are connected, like the pubic, in the median line. The formation of a pubic apophysis or descending ramus to meet the ascending ischium, is a disposition which finds a counterpart in a similar apo- physis from the acetabular end of the ischium to support the pubes, which we have seen in the pelvis of the Crocodiles, excluding the latter bone from participating in the formation of the acetabulum, exactly as the ischia in man and some animals are excluded from the formation of the median symphysis. The greatest extent of this iscbio-pubic coales- cence is seen in the Batrachians and the saltatory Carnivora, Ruminants, and Marsu- pials ; its entire absence in some of the Che- Ionian and in the Saurian reptiles. In the Birds and Bats it is often present even where there is no median symphysis. The iliac element has been seen to be largely developed in its shaft, and placed very ob- liquely on the lumbar vertebras in quadrupeds characterised chiefly by saltatory quadrupedal progression, and requiring long hold for the great muscles of the hip, as the Carnivora, the Deer tribe, the Monkeys, the Horse, and the Frog, — while it is contracted to a remark- able degree in the Walrus and Seal, which approach in their habits the Cetaceans and Fishes, in whom the iliac element of the pelvis is the first to disappear altogether. Its alas we see elongated behind the sacrum in those animals whose pseudo-sedentary habits require a long leverage for the muscles of the back arising from the iliac crest, such as some of the Rodcntia and the Kangaroos — and its alas, on the contrary, to be expanded in those requiring support to the abdominal viscera, either from their size, as in the Pachydermata, or from the erect or semierect position, as in Man and the Sloths. The ischiadic element has been seen to be adapted — by its large development and direct line with the ilia, for saltatory progression, re- quiring a long leverage for the flexor muscles of the leg, as in the Carnivora, the Deer tribe, the Rodents, the Kangaroos, and the Birds; — or, for the support of the sacrum, by its angu- larity with the ilium, and by its elongated tube- rosities, in the Ox, Hippopotamus, and some others, and by ankylosis with the sacrum, as in the Sloths, Bats, and Birds ; — or for the support of a carapace, as in the Armadilloes ; — or for the true ischial sedentary support of the body, as in the Apes and Monkeys. The pubic element has been likewise seen to be in a direct line with the iliac shaft in Man only, destined to the truly erect posture; — and in those animals formed'for quadrupedal pro- gression to be short and placed at a more or 176 PELVIS. less marked ilio-pubic angle, so as to be out of the way of the approximated femurs, in their semi-flexed and angular movements on the pelvis; — but in those habitually requiring a semi-erect position, as the Sloths, to be longer and less angular. It is also unusually long and oblique in the Seal tribe, with re- ference, probably, to a tapering extremity and fish-like outline. The iliac crest and its posterior spines and tuberosity are the hypertrophied, coalesced, and spread-out tubercles of the sacral ribs, a homologue which will be made more evident by the consideration of the homologues of the pelvic ligaments. The epipleural spines of Fishes, and the costal appendages of Birds, show the serial homology of these processes. TJhe Y-shaped epiphysial cotyloid bone of M Serres has been considered by some to represent a marsupial bone ; but, seeing that in the marsupials themselves these Y-shaped bones and the real marsupial bones also, co- exist, this opinion cannot be considered as tenable. In the immature Potoroo, as described by Owen, there is another epiphysial cotyloid bone forming part of the anterior margin of the acetabulum (see fig. 110. Art. Marsu- pialid) ; and one of a similar nature and position is described by Geoffrey St. Hilaire as present in the acetabiila of the Rabbit, and is considered by him to be a rudimental mar- supial bone. There seems, however, greater reason to suppose that both these cotyloid epiphyses are rather of the nature of those complementary ossific points which are seen in the opposed articular surfaces of the bodies of the true vertebrae, and also in the sacral ver- tebrae, and in the articular ends of some long bones, — as those forming the elbow-joint. From the position of the ilio-pectineal emi- nence or spine at the junction of the ilium and pubes opposite to the superior limb of the cotyloid Y-shaped bone, it would seem as if this process were connected with it by a con- tinuation of its ossification upwards. As this spine is coexistent, as seen particularly in the Monotremes, in a great state tof develop- ment with the marsupial bone, the opinion that it represents that bone, seems to be quite untenable. We have seen it most de- veloped in those animals whose posture or structure requires largely-developed psoce parvfs muscles, as in the Marsupials and Monotremes ; the tendons of those muscles being implanted upon them, presenting a close similarity to the implantation of the anterior scaleni muscles into the scalene tubercle of the first rib, to which this eminence would be thus homologically related. The marsupial bones, being developed in the tendons of the external oblique muscle, present the greatest homology, both in position and office, with the spines of the pubes in Man and some animals ; and it would appear, from the manner in which the cremaster muscles play over them, as if they were formed by an os- sification of that part of the tendon which is called, in human anatomy, the external pillar of the ring, or Poupart's ligament, and which is implanted upon the pubic spine.* In support of this opinion, it may be stated that, in Pou- part's ligament near the spine of the pubis, cornicles, similar to those in the stylo-hyoid ligament, are said to have been found in the human subject. The cartilages upon the pubic plate of the Cameleon, before men- tioned, are also significantly homologous to these cornicles and to the marsupial bones, as well as that upon the anterior pubic angle in the Salamander, and considered by Duges as having a marsupial character. The epiphysial plates, forming the articular surfaces of the pubic symphysis in man, are analogous with those which form the auri- cular sacral facets. In the immature Potoroo, there is a tri- angular wedge of bone inserted, with its apex forwards, between the pubic bones posteriorly; and, in the adult Kangaroo, we have seen that a single V-shaped epiphysis is placed with the apex upwards, between the ischial bones at the lower part of the ischio-pubic sym- physis, and forming a prominent vertical median ridge on its anterior aspect (see fig. 99. c). These epiphyses appear to result from ossification, by independent centres, of the inter-pubic and inter-ischial fibro-car- tilages, and to constitute, in these animals, a serial homology with the central ossific points of the sternum and xiphoid appendix ; and they may be considered as represented in the human subject by the inter-pubic fibro- cartilages, which are continued along the ab- dominal walls to their sternal homologues by the linea alba ; as the pubic and ischial ele- ments themselves are represented bythe/w inches. The sacral promontory projects more forwards than downwards, and the lumbar curve is inclined to the left side. In this pelvis the brim is contracted considerably in all its diameters, and this contraction is evidently produced by the crushing down- wards of the sides of the cotylo-sacral arch. The length of the cotylo-sacral rib on the right side, taken from opposite the ilio-pec- tineal eminence to the sacro-iliac angle along the curve, amounts to only ]i inch, while the direct measurement is reduced to 1£ inch. The rib of bone is at the same time much increased in thickness, presenting an almost cubical mass between the cotyloid and sacro- iliac articulations. On the left side, the direct measurement is a little more. In the table of measurements of diseased pelves given by Dr. Murphy, the transverse diameter of the brim in the five ovate pelves amounts to 5 inches only in two cases, and in a third, it is diminished to 4f inches. In many of these cases we may conclude that the cotylo-sacral rib was shortened as well as bent backward. The transverse diameter of the inferior opening is not enlarged in all the above-mentioned cases. In one it amounted only to 3f, and the sub-pubic angle (mainly depending on this diameter) is only 70°. The antero-posterior diameter is, in* three cases, increased to from 4 to 4| inches, while in the remaining two cases it is diminished to 2% and 2-J. These latter measurements, doubtless, depend in great measure upon the position of the coccyx, or, as in the case above given from the Museum of King's Col- lege, upon the flatness of the sacrum, or in its bend. They show, however, that the en- largement of the inferior diameters in not uni- versally characteristic of the general ovate deformity. We may also conclude that the general contraction of the diameters of the brim, which is often found in these pelves, is produced mainly by the shortening of the col^lo-sacral rib of the ilium in the line of pressure, without any aversion of the lower part of the innominate bones. A singular pelvic deformity, related in some degree to this class, is represented in Moreau's plates, in which, by an anterior PELVIS. 187 bend at the lower lumbar vertebras, the sacrum is placet! horizontally backward, and the sacro-vertebral angle diminished to rather less than a right angle. The effect of this is to increase the obliquity of the innominate bones, and the distance from the sacrum to the pubis, to approximate the pubis and coccyx, and to widen the transverse diameters. With the exception of the last-named pecu- liarities, this pelvis presents the condition and appearance of that of a quadruped, in being placed horizontally; the trunk, however, being kept in the vertical position by the re- markable sacro-vertebral bend. The cordiform or angular pelvis. — This distortion presents wide differences to the kind just described. The sacral promontory, though in some measure projecting forwards, yet is more clecidedlv sunk down below its proper level into the cavity of the pelvis, with an in- clination to one side of the median line, in most cases to the left. The lateral masses of the sacrum are likewise bent back, alter- ing the outline of the lateral sacral cur- vature. The vertical curvature of the sacrum is also increased to a great degree ; the hollow of the sacrum, in many cases, being almost bent double. The coccyx is generally placed horizontally. The ilia and ischia on each side are pushed together upwards and towards the sacrum, so that the acetabula are thereby approximated and placed nearer to the sacral promontory. The cotylo-sacral arch presents, in most instances, a very sharp curve near the sacro-iltac joint, and is often bent double, so as to offer a mere chink between the sacral and iliac portions. The iliac wings are generally approximated, the venter being sometimes doubled into a mere fissure, and the crest being curved inwards more than normal, so as to bring the anterior superior iliac spines nearer together; while the posterior extremity of the crest, or iliac tubero$ilyy is bent inwards and forwards over the sacrum, by the weight of the body, acting through the sacro-iliac ligaments. The planes, spines, and tuberosities of the ischia are pushed inwards towards each other, and sometimes turned more upwards, so as to cause a chink or acute bend in the ischial plane, passing downwards and forwards, and which has been compared by Naegele to the fold made by bending pasteboard. The superior rami of the pubes are directed horizontally forwards, being almost, and, in extreme cases, quite pa- rallel to each other anteriorly. This alteration in the direction of the pubic bones takes place, in many cases, by an inward curve in the acetabula at the point of junction of the three pieces of the innominate bone, as indicated by the ilio- pectineal eminence, and the form of the brim will then assume the shape of the letter Y when the deformity is great. In many in- stances, however, the superior pubic rami are bent inwards at an obtuse angle, in the centre, just above the obturator foramina, the bones of the opposite sides almost or entirely meeting at the angle, and continuing parallel with each other to their articulation. The form of pelvis resulting from this bend in the superior pubic ramus has received more par- ticularly the name of the cocked hat or ros- trated pelvis; the latter name being applied from the beak-like projection of the pubis at the symphysis. It is markedly distinguished from those" angular deformities in which the inward bend of the innominate bones takes place at the acetabular junction of their three component pieces, and is found exemplified in most of the specimens exhibiting the greatest contraction of the diameters. The pubic symphysis is, in every case, more or less folded back, straining upon the anterior ligaments. The bending, however, is seen to occur in the osseous portions of the articula- tion forming the pubic angles, generally about the position of the pubic spine, and it is much more considerable in the cases where the an- terior portions of the pubes are parallel to each other. The sub-pubic arch is, in all cases, very considerably narrowed by the parallel position of the superior pubic rami and the approximation of the ischial tu- berosities. In many instances, the latter appear to be pushed forwards and upwards, so that the contraction of the sub-pubic arch is greatest at the ischial rami, just above the tuberosities, above which point the sides of the arch bulge outwards. In the rostrated pelvis, it is often completely obliterated or transformed into a mere chink. The acetabula are elevated and turned more forwards than normal, and in many examples of rostrated pelvis are directed almost quite anteriorly. The angles of both the superior and inferior pelvic planes with the vertebral column are lessened. In a case given by Naegele, the supe- rior plane was at right angles to the spine. The axis of the brim is thus rendered more vertical, and that of the outlet more forward, than in the standard pelvis. The superior plane is often bent into two by the elevation of the acetabula, but, in some instances, the pubic symphysis is pushed upwards above the acetabula. The diameters are all contracted in a greater or less degree, those of the brim most ex- tensively. In this kind of pelvis occurs the greatest diminution of diameters of all the re- corded examples. The diminution, however, is such, that if the irregular form were re- shaped, the diameters would be replaced, i. e. there is no absolute shortening of the bones, or not so much as in the rickety pelves. Examples.— The pelvis of Isabel Redman {fig. 118.), upon whom hysterolomy was per- formed by Dr. Hull in 1794, and which is said to present at the brim the most contracted diameters on record, is affected by this de- formity in its rostrated form to such an extent, that a ball Jf inch in diameter would not pass through it at any part. At the brim, the 4th lumbar vertebra was completely sunk into the pelvis, and in- clined to the left side, and its distance from 188 PELVIS. the pubic symphysis was 2^ inches. The distance between the superior pubic rami at Fig. 118. Pelvis o Isabel Redman. the point of angular bend, was $ of an inch. From the 4th lumbar vertebra at its upper anterior border, to the left acetabulum, was only f of an inch ; on the right side f. The greatest transverse diameter was 5f inches. At the outlet, the distance between the sciatic tuberosities was 3| inches ; between the spines 2f. The greatest contraction of sub- pubic arch was at the sciatic rami, which were only T7^ of an inch distant from each other ; above this, the arch bellied out. The sacrum was bent double, so that the tip of the coccyx was only lTTn inch from the sacral base. The pelvic bones were quite soft, and lighter than natural. The measurements of the pelvis of Jane Foster, who was saved by the* Caesarian sec- tion by Mr. Barlow, are given as follows : — From the fibro cartilage between the 4th and 5th lumbar vertebrae (which is sunk down so as to occupy the normal position of the sacral promontory), to the outside of the projecting pubic symphysis, is 3 inches. From the same point, to the centre of the superior ramus of right pubes, f of an inch, of clear available space. The same measure- ment on the left side, If inch. From the same point, to the right acetabulum £ of an inch ; to the left acetabulum 1^ inch. The greatest available space is, from the left side of the sacral promontory to the left ilium, and amounts to 1£ inch. The greatest lateral space, following the curve, is 5| inches. At the outlet, the distance between the sciatic tuberosities is 1£ inch. The coccyx and lower part of the sacrum are bent upwards, so as to bring the tip of the coccyx to within 1£ inch of the sacral pro- montory, and to 2i inches from the point of contact of the ascending ischial rami, which are so close as to obliterate entirely the sub- pubic arch. The dimensions of the rostrated pelvis of Elizabeth Thomson, who underwent the Cassarian section at the hands of Mr. Wood of Manchester, and died in consequence, are given by Dr. Murphy, as follows : — From the most projecting point of the sacral promontory to the pubic symphysis, 2 inches. From the same point to the left pectineal eminence, f of an inch ; to the right pectineal eminence, f of an inch. The transverse diameter of the brim, 2£ in- ches ; both the oblique, 3^ inches. Cavity : — antero-posterior diameter, 3£ inches ; trans- verse diameter, 2£ inches. Outlet: — antero- posterior diameter, 3£ inches ; transverse diameter, 2f inches. The sub-pubic arch mea- sured 10° only. In a specimen of rostrated pelvis given by Dr. Ramsbotham, the antero-posterior diame- ter of the brim is diminished by the projection of the sacral promontory, and the bend in the pubis, to If inch. The same measurement on the left side of the promontory, 2f inches ; on the right side, 2£ inches. The longest transverse diameter is 4£ inches. At the outlet, the nearest points of the ischial tuberosities are as close as If inch ; but from the tip of the coccyx to the lower border of the pubic symphysis measures 4£ inches. In the opinion of this author, a foetus might be extracted from this pelvis by craniotomy. In Dr. Cooper's case of Caesarian section, the pelvis was affected with the angular de- formity to the extent of reducing'the conjugate diameter of the brim to 1^ inch.; and the trans- verse diameter of the outlet to £ an inch only.* In Dr. Kellie's unsuccessful case of Caesarian operation, the pelvis was of the rostrated kind; the superior pubic rami being as if fractured in the centre, and held only by ligament. The lumbar curve was to the right side, and the 4th vertebra was sunk below the plane of the pelvic brim. The right lumbo-cotyloid diameter was only T% of an inch ; the left, 1^. Between the lumbar vertebra , and the bend of the pubic rami, was only T% of an inch. At the outlet, the intersciatic distance was only 2T7o ; antero-posterior, 3T4o inches. The sacrum was doubled, so that the tip of the coccyx was but 1 inch from the sacral base. The pelvic bones were soft ; but the joints and cartilages healthy. In this case, the patient was only twenty-seven years old, and had borne four children ; the last, three years before her death. In Dr. Radford's two unsuccessful cases of hysterotomy, the deformities were both from malacosteon, and the form rostrated. In one, the circle of space at the brim was only about f of an inch in diameter; the opening Y-- shaped. The distance between the sciatic tu- berosities was li inch, and the sub-pubic arch reduced to a small slit. The subject had previ- ously undergone nine natural deliveries, and one by craniotomy. In the other case, the conjugate diameter was reduced to f of an inch ; and the superior rami were also bent so as to be parallel anteriorly. The patient had borne seven children with great ease previously ; the last case four years before the operation.f Dr. Hamilton's case was also rostrated, the * Med. Observ. and Inq. vol. v. p. 218. f Edinburgh Med. and Surg. Journal, vol. Iv. PELVIS, 189 pubic rami being approximated at the angular bend to £ of an inch. In a case which was operated on by Dr. Haebeke, and described in IS Experience (No. 140.), the inferior pelvic outlet was nearly closed up entirely, the ischial tube- rosities being approximated to within two lines onlj-, and the coccyx and pubes-admitting only one finger between them.* In Mr. Kinder Wood's case, the deformity was rostrated, the most available space at the brim being a circle of 1 inch diameter to the left of the projecting promontory. The antero- posterior diameter was 1 £ inch, but less than f of an inch when the soft parts were at- tached.f A somewhat remarkable variety of the ros- trated pelvis is figured by Dr. Churchill (Jig. 1 1 9.). In this pelvis the superior pubic ramus Fig. 119. Oblong rostrated pelvis. {After Churchill.) is bent at its centre, so as to be nearly ap- proximated to the opposite pubis at that point, and the symphysis projects in a rostrum. The upper part of the sacrum and the pro- montory is, however, thrown back, the cotylo- sacral arch spread out, the antero-posterior diameter increased, and the transverse lessened, somewhat in the same manner, and, doubtless, by the same mechanical conditions, modified only by the yielding of the pubis, as in the oblong pelvis before described. The acetabula, in this pelvis are directed principally forwards and outwards. Causes of the foregoing pelvic distortions. — The principal causes of the preceding partial and complete distortions of the pelvis, are two diseases affecting the osseous system; viz. " rickets" — and " mollifies ossium" or " malacos- teonr Rickets is a very common disease of early life, which is said to be more apt to occur in scrofulous children about the period of denti- tion, but which may occur even after puberty, according to some authors. It is characterised * Lancet, 1840. f Med. Chir. Trans, vol. vii. p. 2G4. by a simple deficiency of the earthy matter of the bones — chiefly of phosphate and carbonate of lime ; while the animal constituents, al- though softened, and rendered less elastic, retain nearly their normal composition. The bones thus rendered pliable, which lie in the lines of weight, pressure, or muscular action, yield slowly and give way to the operating forces, bending in such a manner as the re- sultant direction of pressure and muscular traction, &c., permits them. We must refer the reader to the Article on the PATHOLOGY OF BONE (vol. i. p. 440.) for a more detailed account of this disease. In Rokitansky's Pathological Anatomy, the bones in Rhachitismus infantalis are described to present two separate pathological conditions. In one, the bones are very vascular, soft, fragile, and swollen, with enlarged medullary cavities, and the areolar spaces filled with, and often distended by, a pale, reddish jelly, which press- ing upon the areolar partitions, produces their absorption, and thus the enlargement of the cavities by coalescence. This jelly is also sometimes found effused under the periosteum. In the second variety, the bone is more or less reduced to its cartilaginous elements, the corpuscles (lacunce) empty, the rays obliterated, and the lamellar structure wanting, or fallen asunder/, with corpuscles interposed between the layers. On the last condition the softening of the bones de- pends. The periosteum is more vascular than normal, tumid, and more closely adhe- rent, so as to tear off with it a portion of the softened adjacent bone. It is said to differ from malacosteon in not being a painful disease, and in being capable of cure, with a subsidence of the swelling and reabsorption of the effused substance. In high degrees of the disease, however, atrophy and fragility re- main permanently. The osseous structures affected by rickets are lighter, less marked, thinner, and more porous than normal, or than those affected by mollities ossium, according to Naegele ; — appearing as if they had been steeped in weak acid. The analysis of a rickety humerus and scapula, is given by Rokitansky as follows : Phosphate of lime and magnesia - 15'60 Carbonate of lime - - 2*66 Soluble salts ... 0'62 Total of inorganic matter - 18 '88 Cartilage, vessels and fat - 8T12 100-00 In the humerus, also, was found 10*54 per cent, of fat. Specific gravity of the bone, 0-612. Davy found in 100 parts from the tibia of a rickety child, 74 parts animal and 26 earthy ; and Bostock, in a vertebra affected with the same disease, 79'75 animal, and 20*25 earthy, in 100 parts. WThen this is contrasted with the norma proportions of the osseous constituents in the child, as given by Schreger — viz. 47'20 parts animal, and 48*48 earthy (or about one half 192 even before incineration, left, after exposure to a red heat for some time, a very porous and light inorganic structure. The following results were obtained by thus burning off the organic components — 100 grains of bone,— From the body of an upper lumbar verte- PELVIS. work before cited, of a portion of bone af- fected with this disease we find — in 100 parts : Phosphate of lime and magnesia - 17*48 Carbonate of lime and soluble salts """"" grs. bra left— of earthy matter the last lumbar vertebra lower end of the sacrum ilium (cotylo-sacral rib) ischium (near tuberosity) pubes (near acetabulum) head of the femur neck of the femur 31 27 40 36 33 22 25 Total of inorganic matter 23*80 Cartilage vessels and fat - 76' 20 Specific gravity of the bone 0'721. Among the reasons adduced in favour of the supposition that this disease is sometimes a malignant one, besides the general and violent pains that usually precede the deformity, its incurability and unchecked course towards a fatal termination, have been given. That this result is not invariably the case, the fol- „ shaft of the femur (below trochant) 58 lowing case quoted from Naegele will show, When we compare the foregoing proppr- jn tne fact tnat tne pelvic bones had regained tions of the two constituents of bone with tnejr normai hardness. In the pelvis whence those given by Schreger, as the normal pro- tne foregoing analysis was taken, the bones portions of adult bone — viz., 20*18 animal, had, m0st probably, at some former period and 74*84 earthy matter — the diminution of the ^een mucn softer than they were at the time inorganic constituents appears very striking, of death. Such cases also show, that though and still greater when compared with those of very frequently, the pelvic bones distorted by aged bone ; although less so than in the re- moilities are so soft and pliable as to yield, suits of the analysis of Dr. Leeson, in the sometimes considerably, to the foetal head ; extreme case recorded by Mr. Solly before vet tnat this js Dv no means always the case, given. nor should it be taken, as it is by some ob- The femurs were perfectly normal in shape, stetricians, as a characteristic mark of this as also were the bones of the lower leg, but the pelvis was a rostrated one, the superior disease affecting the pelvis. A very minutely detailed case of pelvic dis- pubic rami being bent in the middle nearly at tortion, resulting clearly from one or other • |_ A „ _i .«,! « ,,,,K s1s\£ti*rY-i£-fts^ c\r\f\ r*r\r\— t • i f» jy** • • ! I XT 1~ dfc right angles, and much deformed and con- ^m(j of mointies ossium, is given by Naegele.* tracted in all its diameters. It was remark- j|-,e subject of the case, after having borne able, that, at the bend of the superior pubic s*x children (five healthy, full sized, and living, rami, and at the suture of the ischio-pubic and the sixth still born), became affected with rami, there was a complete deficiency of this disease, which brought about such exten- osseous matter, so that after maceration, the sive pelvic distortion and contraction, that, pubes separated at these points ; showing that at the seventh labour, the Caesarian operation the connection and continuation of the bone was rendered necessary, from the conse- in these places was purely ligamentous, or quences of which the patient died after the by organic matter, as if resulting from an un- united fracture. fourth day. The shortness of the time m which the pelvis became so much distorted, The sudden diminution of the hard con- together with the extent of the deformity, stituents in the head and neck of the femur, anj the fact that, at the time of the patient's as compared with its shaft, is worthy of ob- decease, it had regained its normal hardness, servation 'in reference to the bending and render the case a very remarkable one. fracture of the femoral neck in old people. Nae^ele considered it as the most contracted The smaller proportion of earthy matter in peivfs that had ever come under his observa- the pubes, as compared with the ilium, and in the sacrum and lumbar vertebrae, as com tion. The anterior wall was pushed upwards and pared with the femoral shaft and pelvis, will tj)e "posterior downwards, the superior plane account for the greater yielding and deformity being bent at the acetabula, so that the which are observed in these parts in the Upper border of the pubic symphysis was angular pelvic distortion, especially in the jeve| wjtn the upper surface of the 4th lumbar rostrated variety, and will be referred to pre- vertebra ; and a line drawn from one anterior sently in the consideration of the mechanism Sl,perior iliac spine to the other, cut the of pelvic deformities. upper surface of the 3rd lumbar vertebra at In the analysis made by Dr. Bostock of jt8 posterior half. The innominate bones were the dorsal vertebrae of a woman affected pushed together, and presented the acute fur- by moilities, he found, that the proportion row? cracked pasteboard, on their inner of the earthy constituents amounted to only surfaces. The sacrum was bent almost one-fifth of the whole weight in one part of double. The measurements are given by the the bone, and to one-eighth only in another ; author, as follow f: — while in a healthy bone from the same part, they amounted to more than one half the * Erfalmmgen und Abhandlungen ; and Appen- whole weight.* In the analysis given, in Rokitan sky's * Med. Chir. Trans, vol. iv. dix to Das SchrJig Verengte Becken. | The measurements used by Naegele, (Rhineland or Prussian,) are very slightly larger than the corresponding English ones. PELVIS. 193 From the anterior inferior iliac spine, to the opposite point on the iliac crest posteriorly — on the left side, 2 inches 4 lines ; on the right side, 2 inches 6 lines. From the apex to the upper surface of the sacrum, 16 lines only ; to the junction of the 1st and 2nd sacral pieces, 1 Oi lines. From the left superior pubic ramus a little internal to the pectineal eminence, to the body of the 4th lumbar vertebra on the same level, only 2i lines. Between the same points on the right side, 6£ lines. The sides of the sub -pubic arch were only 3 lines apart, and more contracted near the sciatic tuberosities than above, by these processes being pushed inwards. The pubes in this pelvis, as repre- sented in the drawings given by the author, are bent in the middle of their superior rami, thus producing the rostrated form. A like case of progressive pelvic deformity from mollities ossium is described by Dr. Cooper.* The patient. Elizabeth Foster, had perfectly easy delivery in her three first labours ; before the fourth, she had, while pregnant, rheumatic fever, and afterwards constantly suffered from universal pains of a rheumatic character, followed by gradual spinal distortion. From the fourth to the sixth labours, they were increasingly difficult, and in the se- venth and eighth she was obliged to be delivered by craniotomy, the sacro-pubic diameter being reduced to 2 inches. Three years after, she again became pregnant, when the sacro-pubic diameter was found to be reduced to 1^ inch, becoming gradually narrower on each side. Caesarian section was performed, under which she sank. After death, the sub-pubic arch was found to be so much contracted, that the sciatic rami were little more than £ an inch apart. The pelvis was so soft and spongy, that the finger could be easily pressed into its substance, and at the place of attachment of some of the muscles, the osseous substance was found raised into eminences, as if pulled out. Eight similar progressive cases were ob- served by Barlow. One woman, on whom he performed hysterotomy unsuccessfully, had given birth to two children, and afterwards had become lame and bed-ridden for four years. In another case of Caesarian section, also resulting from malacosteon, the woman had previously borne children, and been deli- vered by the crotchet. In this instance, the conjugate diameter was reduced to ]i inch ; the right sacro-cotyloid, to 2£ ; the left, to ]£ inch. The last lumbar vertebra and sa- cral promontory formed a great tumour-like curve in the pelvic cavity, which he was able to distinguish from an exostosis only by its yielding easily to the pressure of the fingers, which a tumour of that nature would not do.f Other cases of this progressive kind have been before alluded to. The question as to whether the rickety pelvis ever assumes the angular or cordifonn shape, is one which has occupied consider- ably the attention of many obstetricians. * Med. Observations and Inquiries, vol. v. t Essays, p. 355. Supp. It was very ingeniously advocated by Dr. Hull in his Letters to Symmonds, and laid down by the younger Stein and others on the Continent, that the ovate form of pelvic dis- tortion with contraction of the diameters of the inlet and enlargement of those of the outlet of the pelvis, was the characteristic and invariable form of rickety disease; as that of the angular cordiform shape, with contraction of both outlets, was of malacosteon; and the opinion seems to be still frequently held by obstetricians both abroad and in this country. Dr. Murphy considers that, though the oval pelvis is not the necessary consequence of rickets, nor the cordiform of mollities ossium, yet that " of necessity, the softened adult pel- vis would take the shape called cordiform, while the infant pelvis would be transversely lengthened;" — unless in the infant, "the spine be softened and bent as well as the pelvis," so as to throw the weight of the body more upon the pelvic cavity, as by a " backward curvature " such as he has figured, in which cases he supposes that angular deformity takes place in the child.* This conclusion he draws from the hypothesis that in the child, because of the straightness of the spine, a line passing through the centre of gravity, and conse- quently the weight of the spine, would fall altogether I'M advance of the pelvic cavity, and that consequently the acetabula would be pressed up behind it, and of necessity, diverge, because of the sacrum pressing down between them ; while, in the adult, the weight of the body falls within the pelvis and between the acetabula, which consequently would be pressed inwards towards it. In considering the mechanism of these pelvic deformities we shall again have occasion to refer to this ex- planation. But this author also thinks that a condition of bones identical with or allied to rickets, may be induced in young adult females, whose health is depreciated, and powers of nutrition impaired, by the con- fined or unhealthy nature of their employ- ment ; and that there is thus constituted a special kind of mollities ossium, a rickets of adults, in which cases the pelvis will assume the cordiform shape. The frequent occurrence of spinal deformities at this age, is an evidence of a deficiency in the supply of osseous mate- rial. Naegele, who warmly combats the opinion that the infant rickety pelvis is always ellip- tical, quotes in support of his arguments against it, a case attended by Dr. J. A. Beyerle and Professor Fischer, of Mannheim. The history of the case, and the appearance of the patient herself, and of her father, brothers, and sister, indicated scrofula and extensive rickety deformity existing in the family. The patient had been deformed from the earliest youth, and had not attempted to walk or stand till she was seven years old. She was of very small stature, — 4 feet 3 inches, had a projecting sternum, an awk- ward, shambling, waddling gait, and a remark- * Lectures on Parturition, p. 32. 192 PELVIS. even before incineration, left, after exposure to a red heat for some time, a very porous and light inorganic structure. The following results were obtained by thus burning off the organic components — 100 grains of bone, — From the body of an upper lumbar verte- bra left— of earthy matter - -31 „ the last lumbar vertebra - - 27 „ lower end of the sacrum - - 24 „ ilium (cotylo-sacral rib) - - 40 „ ischium (near tuberosity) - - 36 „ pubes (near acetabulum) - - 33 „ head of the femur - - -22 „ neck of the femur - - - 25 „ shaft of the femur (below trochant) 58 When we compare the foregoing propor- tions of the two constituents of bone with those given by Schreger, as the normal pro- portions of adult bone — viz., 20'18 animal, and 74'84 earthy matter — the diminution of the inorganic constituents appears very striking, and still greater when compared with those of aged bone ; although less so than in the re- sults of the analysis of Dr. Leeson, in the extreme case recorded by Mr. Solly before given. The femurs were perfectly normal in shape, as also were the bones of the lower leg, but the pelvis was a rostrated one, the superior pubic rami being bent in the middle nearly at right angles, and much deformed and con- tracted in all its diameters. It was remark- able, that, at the bend of the superior pubic rami, and at the suture of the ischio-pubic rami, there was a complete deficiency of osseous matter, so that after maceration, the pubes separated at these points ; showing that the connection and continuation of the bone in these places was purely ligamentous, or by organic matter, as if resulting from an un- united fracture. The sudden diminution of the hard con- stituents in the head and neck of the femur, as compared with its shaft, is worthy of ob- servation 'in reference to the bending and fracture of the femoral neck in old people. The smaller proportion of earthy matter in the pubes, as compared with the ilium, and in the sacrum and lumbar vertebrae, as com- pared with the femoral shaft and pelvis, will account for the greater yielding and deformity which are observed in these parts in the angular pelvic distortion, especially in the rostrated variety, and will be referred to pre- sently in the consideration of the mechanism of pelvic deformities. In the analysis made by Dr. Bostock of the dorsal vertebrae of a woman affected by mollities, he found, that the proportion of the earthy constituents amounted to only one-fifth of the whole weight in one part of the bone, and to one-eighth only in another ; while in a healthy bone from the same part, they amounted to more than one half the whole weight.* In the analysis given, in Rokitan sky's * Med. Chir. Trans, vol. iv. work before cited, of a portion of bone af- fected with this disease we find — in 100 parts : Phosphate of lime and magnesia - 17 48 Carbonate of lime and soluble salts 6'32 Total of inorganic matter 23*80 Cartilage vessels and fat - 76'20 Specific gravity of the bone 0'721. Among the reasons adduced in favour of the supposition that this disease is sometimes a malignant one, besides the general and violent pains that usually precede the deformity, its incurability and unchecked course towards a fatal termination, have been given. That this result is not invariably the case, the fol- lowing case quoted from Naegele will show, in the fact that the pelvic bones had regained their normal hardness. In the pelvis whence the foregoing analysis was taken, the bones had, most probably, at some former period been much softer than they were at the time of death. Such cases also show, that though very frequently, the pelvic bones distorted by mollities are so soft and pliable as to yield, sometimes considerably, to the foetal head ; yet that this is by no means always the case, nor should it be taken, as it is by some ob- stetricians, as a characteristic mark of this disease affecting the pelvis. A very minutely detailed case of pelvic dis- tortion, resulting clearly from one or other kind of mollities ossium, is given by Naegele.* The subject of the case, after having borne six children (five healthy, full sized, and living, and the sixth still born), became affected with this disease, which brought about such exten- sive pelvic distortion and contraction, that, at the seventh labour, the Caesarian operation was rendered necessary, from the conse- quences of which the patient died after the fourth day. The shortness of the time in which the pelvis became so much distorted, together with the extent of the deformity, and the fact that, at the time of the patient's decease, it had regained its normal hardness, render the case a very remarkable one. Naegele considered it as the most contracted pelvis that had ever come under his observa- tion. The anterior wall was pushed upwards and the "posterior downwards, the superior plane being bent at the acetabula, so that the upper border of the pubic symphysis was level with the upper surface of the 4th lumbar vertebra ; and a line drawn from one anterior superior iliac spine to the other, cut the upper surface of the 3rd lumbar vertebra at its posterior half. The innominate bones were pushed together, and presented the acute fur- row, like cracked pasteboard, on their inner surfaces. The sacrum was bent almost double. The measurements are given by the author, as follow -j-: — * Erfahrutigen und Abhandlungen ; and Appen- dix to Das Schrag Verengte Becken. f The measurements used by Naegele, (Rhineland or Prussian,) are very slightly larger than the corresponding English ones. PELVIS. 193 From the anterior inferior iliac spine, to the opposite point on the iliac crest posteriorly-— on the left side, 2 inches 4 lines ; on the right side, 2 inches 6 lines. From the apex to the upper surface of the sacrum, 10 lines only ; to the junction of the Island 2nd sacral pieces, IQi lines. From the left superior pubic ramus a little internal to the pectineal eminence, to the body of the 4th lumbar vertebra on the same level, only 2± fines. Between the same points on the right side, 6£ lines. The sides of the sub- pubic" arch were only 3 lines apart, and more contracted near the sciatic tuberosities than above, by these processes being pushed inwards. The pubes in this pelvis, as repre- sented in the drawings given by the author, are bent in the middle of their superior rami, thus producing the rostrated form. A like case of progressive pelvic deformity from mollifies ossium is described by Dr. Cooper.* The patient, Elizabeth Foster, had perfectly easy delivery in her three first labours ; before the fourth, she had, while pregnant, rheumatic fever, and afterwards constantly suffered from universal pains of a rheumatic character, followed by gradual spinal distortion. From the fourth to the sixth labours, they were increasingly difficult, and in the se- venth and eighth she was obliged to be delivered by craniotomy, the sacro-pubic diameter being reduced to 2 inches. Three years after, she again became pregnant, when the sacro-pubic diameter was found to be reduced to 1£ inch, becoming gradually narrower on each side. Caesarian section was performed, under which she sank. After death, the sub-pubic arch was found to be so much contracted, that the sciatic rami were little more than \ an inch apart. The pelvis was so soft and spongy, that the finger could be easily pressed into its substance, and at the place of attachment of some of the muscles, the osseous substance was found raised into eminences, as if pulled out. Eight similar progressive cases were ob- served by Barlow. One woman, on whom he performed hysterotomy unsuccessfully, had given birth to two children, and afterwards had become lame and bed-ridden for four years. In another case of Caesarian section, also resulting from malacosteon, the woman had previously borne children, and been deli- vered by the crotchet. In this instance, the conjugate diameter was reduced to ]i inch ; the right sacro-cotyloid, to 2£ ; the left, to \\ inch. The last lumbar vertebra and sa- cral promontory formed a great tumour-like curve in the pelvic cavity, which he was able to distinguish from an exostosis only by its yielding easily to the pressure of the fingers, •which a tumour of that nature would not clo.f Other cases of this progressive kind have been before alluded to. The question as to whether the rickety pelvis ever assumes the angular or cordiform shape, is one which has occupied consider- ably the attention of many obstetricians. * Med. Observations and Inquiries, vol. v. t Essays, p. 355. It was very ingeniously advocated by Dr. Hull in his Letters to Symmonds, and laid down by the younger Stein and others on the Continent, that the ovate form of pelvic dis- tortion with contraction of the diameters of the inlet and enlargement of those of the outlet of the pelvis, was the characteristic and invariable form of rickety disease; as that of the angular cordiform shape, with contraction of both outlets, was of 'malacosteon; and the opinion seems to be still frequently held by obstetricians both abroad and in this country. Dr. Murphy considers that, though the oval pelvis is not the necessary consequence of rickets, nor the cordiform of mollifies ossium, yet that " of necessity, the softened adult pel- vis would take the shape called cordiform, while the infant pelvis would be transversely lengthened;" — unless in the infant, "the spine be softened and bent as well as the pelvis," so as to throw the weight of the body more upon the pelvic cavity, as by a " backward curvature" such as he has figured, in which cases he supposes that angular deformity takes place in the child.* This conclusion he draws from the hypothesis that in the child, because of the straightness of the spine, a line passing through the centre of gravity, and conse- quently the weight of the spine, would fall altogether in advance of the pelvic cavity, and that consequently the acetabula would be pressed up behind it, and of necessity, diverge, because of the sacrum pressing down between them ; while, in the adult, the weight of the body falls within the pelvis and between the acetabula, which consequently would be pressed inwards towards it. In considering the mechanism of these pelvic deformities we shall again have occasion to refer to this ex- planation. But this author also thinks that a condition of bones identical with or allied to rickets, may be induced in young adult females, whose health is depreciated, and powers of nutrition impaired, by the con- fined or unhealthy nature of their employ- ment ; and that there is thus constituted a special kind of mollities ossium, a rickets of adults, in which cases the pelvis will assume the cordiform shape. The frequent occurrence of spinal deformities at this age, is an evidence of a deficiency in the supply of osseous mate- rial. Naegele, who warmly combats the opinion that the infant rickety pelvis is always ellip- tical, quotes in support of his arguments against it, a case attended by Dr. J. A. Beyerle and Professor Fischer, of Mannheim. The history of the case, and the appearance of the patient herself, and of her father, brothers, and sister, indicated scrofula and extensive rickety deformity existing in the family. The patient had been deformed from the earliest youth, and had not attempted to walk or stand till she was seven years old. She was of very small stature, — 4 feet 3 inches, had a projecting sternum, an awk- ward, shambling, waddling gait, and a remark- * Lectures on Parturition, p. 32. 194 PELVIS. able projection of the abdomen, caused by a great increase in the normal forward bend of the lumbar curve ; with an equivalent projec- tion of the sacrum posteriorly, from the hori- zontal position of that bone ; so that the plane of the superior pelvic opening was, in the upright position, completely vertical. The lower extremities were not, however, de- formed, neither the bones of the upper nor lower leg being bent. About the age of thirty, she became pregant, and died after the neces- sary performance of the Caesarian section. On being examined, the lumbar vertebra were found much curved forwards, and small, slender, and weak. The sacrum was placed nearly horizontal from before backwards, its posterior part projecting very much behind (see fig. 120. a). It was sunk so much between the ilia that the centre of the 4th lumbar ver- tebra was opposite to the upper border of the pubic symphysis, and was bent so much about the 3rd sacral vertebra, that the distance of the apex from the promontory was only 1 inch 9£ lines, and from the first transverse sacral line, only 15 lines. The innominate bones were thin and slender, and the centres of the iliac wings more translucent than in the healthy bone. On the planes of the ischia was the cracked pasteboard fissure, running obliquely from above downwards and forwards opposite the cotyloid cavities, and said to be charac- teristic of the pelvis diseased by malacosteon. The left tuber ischii was more elevated than the right, and the ascending branch of the same bone more bent. A direct line drawn from one anterior superior iliac spine to the other, cut the body of the 4th lumbar ver- tebra 3 lines below its upper surface (d\ and measured 8 inches 7 lines. From the anterior inferior iliac spine to the posterior extremity of the linea innominata, measured on both sides, 2 inches. From the ischial tuberosity Angular rickety pelvis. (After Naegele.) to the most elevated portion of the iliac crest, measured on the right side, 6 inches, on the left, 5 inches 7 lines. From the tuber ischii to the pectineal eminence, measured on the right side, 3 inches ; on the left, 2 inches 11 lines. The height of the pubic symphysis was IS lines. The superior opening was angular, with an acute and somewhat symmetrical curve of the cotylo-sacral ribs on each side, and a gradual and equable curve inwards at the union of the ilium and superior pubic rami at the aceta- bula (Z>), which brings the body or acetabular portion of the pubis, to within 5 lines of the body of the 4th lumbar vertebra, the under surface of which is on the same level ; the same measurement on the left side being 6^ lines. The distance from the anterior and lower border of the same vertebra to the upper border of the pubic symphysis, was 1 in. 1 line ; and from one superior branch of the puj>is to the other near the acetabula, 1 in. 7 lines. The pubis presented the usual out- ward bend at the spines on each side of the symphysis (c). — At the inferior opening, the distance between the ischial tuberosities was 1 in. 5£ lines only; and the nearest approxi- mation of the ascending branches, 1 in. 1 line. The shape of this pelvis, of which the author gives three lithographic sketches, had caused it to be frequently mistaken for the results ofmol- lities ossiuni) but the appearance of the bones in texture, lightness, and slenderness, £c., was truly rickety, and with the history of the case, gave no reason whatever for the sup- position that malacosteon had ever been pre- sent or supervened. In addition to this case, the same eminent observer adds, that he has himself seen two examples of this deformity in children, and that in the pathological collection at Strasbourg, as he was informed by Professor Stoltz, that there are two skeletons of rickety children, of one and eight years old respectively, in which the pelves are affected with the angular deformity. In the Anatomical Museum at Breslau, also, on the authority of Professor Betschler, is another example of this kind, exhibited by the pelvis of a rickety female child aged ten years. Many other similar examples are given by Burns, Otto, Wallach, and Krum- bolz. Rokitansky also found the angular de- formity in rickety pelves, but in a minor degree of distortion.* In the Museum of King's College, London, are two rickety pelves of children of about from four to six years old, both of which are affected with angular deformity of the pelvis. Fig. 121. Angular child 's pelms from rickets. A drawing of one of these is given in figure 121. In the larger of the two, the curves of the femurs and leg bones are bent di- * Pathological Anatomy : Pelvic Abnormalities. PELVIS. 195 rectly forwards, without any lateral deviation inwards or outwards. In the Hunterian Museum also, there is a rickety skeleton of a child of six years, in which the pelvis presents the angular deformity and approxi- mation of the acetabula. In none of these specimens is there any great backward curva- ture of the spinal column, though, in the last instance, the sacrum is bent so much forward, that the tip of the coccyx is almost on a level with the superior plane in the centre of the opening. It is, however, especially remarkable that in all these last-mentioned specimens, as well as in that figured by Naegele and just described, the angle of the bend or culm of the lateral curve produced by the pressure inwards of the heads of the femurs, takes place in the acetabula at the line of junction of the two upper pieces of the inuominatum, and not in the superior branch_of the pubis itself, as in most of the cases resulting from mollifies ossium. This is evidently produced by the more facile and greater yielding of the as yet unossified cotyloid cartilage, rendered softer and more tardy in ossifying, by the effect of the disease upon its nutrition. That such a yielding does take place in this cartilage from disease and pressure is shown still more strikingly in another case in the Hunterian Museum (No. 3423.), in which it has bent outwards, instead of inwards, and thus is produced an elliptical distortion of the pelvis. This skeleton is from a young subject, in which the pelvic bones had not yet become soldered together. The head and neck of the left femur are nearly destroyed by caries, which doubtless also extends to the acetabulum itself. Both the femurs are extremely flexed and adducted on the pelvis, and seem, espe- cially on the diseased side, to have, by the constancy of this position, pushed upwards and backwards the pubis, so as to cause a distinct bend at the cartilaginous cotyloid line of junction, and an elevation of the pubic symphysis. By this means, the acetabula are pushed outwards, and the superior pelvic opening assumes an elliptical shape; though the cotylo-sacral arch is but slightly spread out, and the ischial tuberosities are normally placed. The lumbar curve and sacral pro- monotory deviate slightly towards the left side, and the bones are remarkably small and light, showing the prevalence of the rickety tendency. From these cases, it seems reasonable to draw the conclusion, that the softened infant pelvis does in a great many cases assume the cordiform shape, and that without any back- ivard spinal curvature ; but, on the contrary, the case quoted by Naegele shows that it is co-existent with excessive forward curvature of the lumbar spine, such as would throw the weight of the body entirely in front of the vertically placed pelvic brim ; and thus, accord- ing to Dr. Murphy's view, of necessity, pro- duce the ovate and not the angular deformity. We may also conclude that when, by mecha- nical causes, the angular shape is impressed upon the softened infant pelvis, it will yield most readily and extensively at its weakest point — viz. the still cartilaginous line of ilio-pubic junction in the acetabulum ; and that, as in the instances now given, and indeed in all that I have myself examined, the shape of the angu- lar pelvis resulting from rickets in infancy is never rostrated, in the sense to which that expression is confined in the present article ; but, that this form is usually seen only in the angularly deformed pelvis resulting from the mollities ossium of adults, and commenc- ing after the pelvis has attained its adult de- velopment and consolidation, when the bend most commonly takes place in the centre of the superior pubic ramus, which, in thick- ness, and, in some diseased conditions, as the analysis before given shows, in composition also, is the weakest point of the pelvic circle in the adult. This will, I think, be found a general and useful distinguishing mark between the angular pelvis resulting from rickets, and that of the adult mollifies ossium. Whether, on the other hand, the adult pel- vis, softened by mollities ossium, or the rickets of adults, ever assumes the ovate form of dis- tortion, is a question of supposition merely. I have not been able to find any recorded cases of such a result, though there is no evi- dent reason why this should not occur, under certain mechanical conditions. Rokitansky found that the ovate and hour-glass distortions are, almost without exception, the result of in- fantile rickets. MECHANISM OF THE PRECEDING PEL- VIC DISTORTIONS. — In considering the forces which operate in producing the two principal varieties of pelvic distortion previously treated of, it is necessary carefully to separate those resulting from mechanical position, from those which arise from muscular action alone. In considering the former, it will be necessary as carefully to separate the idea of the line of gravity— i. e. a perpendicular line let fall from the centre of gravity — from that of the line of pressure, which must necessarily pass through the osseous supporting structures, whatever disposition they may have. The centre of gravity of the trunk itself is that which influences most considerably the form of the softened pelvis in the sitting as well as the upright position. This is placed by Weber in the transverse vertical plane of the spinal column, which here falls consi- derably in front of the vertebrae, in the tho- racic cavity, at the level of the sterno-xiphoid articulation (see^/Jg. 122. A, a). In the most easy standing position, this centre of gravity is placed directly above that of the whole body, at the sacro-lumbar articu- lation (A, c) ; so that perpendicular lines let fall from each to the ground will exactly co- incide, and (in the well-made subject, after passing through the sacral promontory and the acetabula) fall between the feet as the basis of support. In the sitting posture, it falls a little posterior, between the ischial tu- berosities. To preserve the standing posture, it is o 2 196 PELVIS. necessary that the line of gravity of the whole body — viz. that from the lower centre — should Fig. 122. A. Diagram of the lines and centres of gravity of the trunk, a b ; and of the whole body, c d. b. Outline of the lines of pressure in the pelvis and legs in the ovate rickety distortion, during the standing posture. — a b lines of direction of, the pressure of the heads of the femurs in the ace- tabula, — upwards and outwards. c. Outline of the pelvis and legs in the angular rostrated pelvis of the adult, resulting from molli- ties ossium. ab, a c, direction of pressure in the acetabula when the legs are not deformed, — upwards and inwards. D. A similar outline in the angular rickety pelvis of the child, when the legs are bent outwards, — di- rection of pressure inwards. E. Outline of abnormal antero-posterior curves of the spine, pelvis, and legs, a b, direction of the pressure in the acetabuia backwards increased by the forward curve of the femora, c d, line of traction of the "psoas muscles increasing the de- formity of the pelvis. fall anywhere between the extent of longitude of the feet (c d), If the trunk, however, bend forward, its centre and line of gravity is advanced beyond that of the whole body, and a share of the sup- port of the trunk, equivalent to the degree of distance of these two lines (b, d), falls upon the muscles and ligaments of the posterior part of the spine, and a corresponding strain upon their attachments to the sacrum and posterior part of the pelvis. This instance may be taken as an example of many others, in which the me- chanical position of the line of gravity in- fluences muscular action, the effects of both falling upon the lines of pressure and support in the pelvis. For the preservation of the sitting position, it is only necessary that the line of gravity of the trunk (a b) should fall within the extent of the basis of support, which is, from more or less of the whole extent of the hams in front to the ischial tuberosities behind. Hence the greater facility with which a person sitting down is pushed backward than forward. The line of pressure, on the other hand, passing down the centre of the bodies of the vertebrae will, in the well-made subject, when standing on both legs or sitting, divide at the sacral promontory, into two equal parts, each of which traverses, first the lateral sacral masses to the sacro-iliac joint ; from this point, in the upright position, it passes along the cotylo-sacral rib to the heads of the femurs, describing in its course the C-like curve. In the sitting posture, it passes down the ischio-sacral buttress to the tuberosities. It will be borne in mind that each of these standing and sitting arches has its tie, which prevents it equally from starting outwards or pressing inwards at the extremities ; that for the cotylo-sacral arch being the united supe- rior pubic rami, and that for the ischio-sacral arch, the united ischio-pubic rami. The co- tylo-sacral arch and its pubic tie, united at the acetabula, and placed in the same plane, form in man, as we have seen, a lateral arch made up of the two halves, which supports on its culm the inward pressure of the head of the femur. The cotylo-sacral portion also sustains, in addition, its upward and backward pressure. The first effect of the softening of the os- seous supports in this line of pressure is to increase the natural curves which occur in it. Thus we see an increase in the dorsal, lumbar, and sacral curves, in the cotylo-sacral, fe- moral, and tibial (fig. 122. E). The next effect is to produce lateral curves, which present generally their concavities towards the line of gravity, and are always associated with com- pensating curves, so as to keep the line of gravity within them, about which they pro- duce a wavy line, as is seen in the deformed spine. When this is not the case, the support of the weight falls more upon the tension of the muscles, and ligaments, and parts of bone on the convex side. In the pelvis, and, to some degree, in the bones of the legs, however, these results are modified by the lateral duplication and division of the lines of pressure ; and in the pelvic skeleton this effect is still further increased by the cir- cular union of the lateral structures, and by the pressure or traction of the bones of the legs, conjointly or individually. The alteration of the position of the centre of gravity of the trunk, by deformity of the spine low down, will also have its effect upon the pelvis, by necessitating a constrained and unnatural position to prevent the body falling. Deformities confined to the upper part of the spine are seldom accompanied by deformed pelvis, owing, probably, to the little effect they have in altering the centre of gravity. In addition to these general changes from mechanical pressure, there is, in this softened state of the bones, the powerful effect of combined muscular action. The influence of continued posture on these changes will be found to be the origin of most of the differences of form we have seen in pelvic distortions. Let us consider the effects of mechanical position and muscular action in the recumbent, — sitting, — and standing posi- tions respectively, on the softened pelvis In lying upon Ike back, the softened pelvis PELVIS. 197 will have a tendency to become flattened antero-posteriorly, by the sinking of the pubic arch, at the same time that the traction of the femurs and muscles of the lower extremi- ties outwards will tend to separate the aceta- bula and increase the transverse diameters. This I apprehend to be the commencement of the elliptical pelvic deformity, which occurs in the majority of the softened pelves of infants, whose most frequent and long-continued po- sition is the dorsal recumbent. The angles of the pelvis with the spine will also have a tendency in this posture to become in- creased by the weight of the inferior extremi- ties. If the softening be great, and the position long-continued, the symphysis pubis would also sink, producing the hour-glass form of pelvis ; a disposition which would be increased by the traction of the levator ani and weight of the bladder. There wrould also be a tendency to flattening of the sacrum. In lying upon the side, on the other hand, there is a pressure, through the trochanters, upon the acetabula, which, if long and fre- quently-accustomed, will cause the lateral pelvic arches to yield and bend inwards at the cotyloid line of junction, in children as yet unossified, and produce the first bend or tendency to the angular deformity. The effect of these first impressions are, as Dr. Ramsbotham observes, illustrated by making an elbow in a piece of wire subjected to pressure at each extremity. In the unde- veloped pelvis also, the facility with which these impressions are made upon the pubic tie is rendered greater by the greater tardiness of its ossification than" in the other innomi- nate pieces. In some instances, pelves seem to have been impressed in this manner on one side only, so that the two sides present an approach to the two different varieties of de- formity, as will be presently alluded to. In the sitting and standing positions, a more powerful distorting influence is brought into play — viz. the pressure of the weight of the body on the softened pelvic arches. The sitting posture, when the elliptical form has already been impressed upon the pelvis, will still further tend to separate the .acetabula by the starting outwards of the lower extremities of the ischio-sacral arch under the pressure of the weight of the trunk on the sacrum ; and thus the separation of the tuberosities, the enlargement of the transverse diameter of the outlet, and the spreading out of the sub- pubic arch take place. At the same time the sacral promontory sinks into the pelvis under the weight of the trunk, while the lower part of the sacrum is kept forwards by the sciatic ligaments, so that a bend takes place in the middle of the bone. This bend will be still further increased by the divergence of the ischial tuberosities, permitting the weight of the spine to be brought to bear upon the coccyx and lower end of the sacrum and against the sitting surface. The total direc- tion of the pressure on the ischial tuberosities being upwards and backwards, the curve of the ischio-sacral arch (coinciding with that of the cotylo-sacral at the top of the sciatic notch) takes place in that direction, and in- creases the acuteness of the C-like curve. These effects upon the sacrum and ilia, and pelvis generally, will be increased by the action of the powerful erector spinas muscles, and psoas and iliacus muscles, exer- cised in keeping the trunk erect upon the pelvic lever (see fg. 122 E, c d). These muscles have, in addition, much influence in shortening the spinal column itself, already bending under the weight of the body, and,— following the general tendency of elongated substances yielding to pressure at both ends to twist laterally, — the lumbar curve and sacral promontory become placed on one side the median line. This tendency, from reasons before explained, is generally to the left. Under the increased inclination of the pelvic angle, the abdominal muscles will tend to draw the flattened pubes upwards still nearer the sacral promontory, diminishing the con- jugate diameter. In 'extreme deformity, the iliac wings are pressed still further outwards and everted by the pressure of the lower ribs resting upon them, as we have observed in one of the detailed examples. But when the lateral pelvic arches are al- ready impressed with the angular deformity, the sitting posture has the effect of merely increasing the inward bend, and approximat- ing the acetabula and sc'atic tuberosities to the sacrum, pressed down by the superin- cumbent weight. Dr. Rigby mentions that frequent riding on horseback at an early age will produce contraction of the inferior outlet, even in the healthy pelvis, and that the females of those American nations who ride much bear few children, and are often three or four days in severe labour. In certain cases, in which the acetabulum on one skle only has been pressed inwards by the constant use of the lateral recumbent po- sition, or in which the centre of gravity of the trunk has been permanently shifted to one side by the spinal bend, a habit is acquired of sitting more upon one ischial tuberosity thar the other. This unequal pressure produces inequality of distortion, and presses the tu- berosity and acetabulum of that side inwards, while the opposite one presents the usual di- vergence of the elliptical distortion. This effect is also contributed to in like manner, under the same circumstances, in the standing position, by the pressure being greater and more frequent upon one fenfur than the other ; and thus we have produced a sort of oblique deformity, of which 1 have seen se veral specimens/ In the Museum of King's College are three skeletons, all presenting more or less a ten- dency to this peculiar modification of the ovate deformity. In the Hunterian Museum is another, in an adult female skeleton, still more marked. It is somewhat remarkable that, in all these examples, the trunk is bent towards the right side, and the lumbar curve and sacral projection towards the left; so that the line of gravity, and o 3 J9S PELVIS. consequently the greatest share of supporting the weight of the body, falls nearer the left leg and the left side of the pelvis. The effect is such as to produce great similarity in the form of all these pelves, which vary only in the de- gree of distortion. The sacral promontory is directed to the left side, while the sacral con- cavity is more or less twisted so as to face the left acetabulum. The innominate bone of the left side is placed lower and more ver- tical than that of the right side, which appears longer and less bent ; so that the left ischial tuberosity projects lower and more vertically than the right, which is everted and directed outwards. The left acetabulum is brought nearer to, and more directly under, the sacral promontory, the cotylo-sacral arch being more curved than the right ; while the right sacro- iliac joint and lateral sacral mass are higher, the cotylo-sacral curve more open, the iliac wing more spread, and directed, .like the acetabulum, more forwards, and the ischio- pubic ramus placed more obliquely, than those on the left side. In the female Hunterian skeleton, the ob- liquity of the spine and pelvis are so great, that the upper dorsal vertebrae are placed above the right sacro-iliac joint. The femora are shortened, and curved forwards and out- wards, and the leg bones forwards and inwards, in compensating curves. The left knee, how- ever, is more under the line of gravity than the right. A tendency to a somewhat similar twist is seen in an adult hydrocephalic ske- leton in the same collection. These pelves present, at first sight, some re- semblance to the very different " obliquely ovate" pelvis of Naegele. The most charac- teristic differences are, the presence of other rickety appearances, and the want of the co- incidence of lateral deviation of the pubic symphysis with the sacro-iliac ankylosis and malformation of the latter. Rokitansky includes all the pelves which present a want of symmetry at the sides under the general term of oblique pelves, after Osian- der's classification, in which he comprehends by far the greatest number of pelvic deformi- ties of all kinds. He gives, as a characteristic of this class, — approximation of the sacral promontory to the pectineal eminence on one side, which side has also a higher level and a less pelvic inclination than the opposite one, originating in a lateral curve and torsion of the sacrum towards the contracted side, — and straightening out of the linea innominata on the opposite side, between the sacro-iliac joint and the acetabulum. It includes the frequent pelvic deviations resulting from lateral curva- ture of the spine, but most frequently arises from rickets, or displacement of the femur by hip-joint disease or violence. To a rickety child, who rarely begins to walk till after the usual age, by far the most frequent positions are thr two which we have just considered, and the mechanism of these positions, in my own estimation, is quite suf- ficient to account for the first impression of the most frequent deformity of the rickety pelvis, the ovate, as well as for the not un- common angular infantile distortion. In standing and walking the supporting pres- sure on the pelvic structures is sustained, either divided or alternately undivided, be- tween the cotyloid cavities and the sacrum. From the peculiar disposition of the cotyloid articulation, the pressure of the head of the femur is exerted in two directions, 1st, upward and backwards along the cotylo-sacral rib, which is the principal line of pressure, and, 2nd, inwards on the lateral pelvic arch. In the up- right position the softened cotylo-sacral rib yields in the direction of its C curve, which becomes more acute as the sacrum sinks. An increased obliquity of the pelvic inclination, such as has been stated to be generally conse- quent upon the advance of the sacral promon- tory and increased lumbar curve in the ellipti- cal deformity, will bring the line of gravity, both of the trunk and whole body, in front of the acetabular supports, which will cause them to increase the backward curve when pressure is exerted upon them (see Jig. 122. E, a b.), But that such a condition is produced by a greater obliquity of the normal infant pelvis than that of the adult, or that this alone is sufficient to account for the elliptical defor- mity taking place usually in the infant pelvis, by causing divergence of the acetabula under pressure during the upright posture, as asserted by Dr. Murphy, is a conclusion which the re- sults of the observations given in a former section, as well as those of Weber, therein stated, will not at all admit of ; — for, as was there seen, the obliquity of the normal infant pelvis is not at all ^greater, if as great, as that of the adult. But if the acetabula are already separated by the elliptical deformity, or if the leg bones yield inwards, so that the pressure on the aceta- bular articular surface at its upper vaulted part is directed upwards and outwards, as seen in the accompanying diagram (fig. 122. B, a, 6), then the pressure inwards of the heads of the fe- murs upon the lateral pelvic arches is taken off, there is traction instead of pressure on the pubic tie, the acetabula become still more widely separated, and the elliptical deformity increased. In such specimens of ovate pel- vic deformity as have the leg bones attached, I have found the tibiae and fibulas bent much inwards, or the leg bones so disposed by an inward knee-bend as to take off the inward pressure at the acetabula, and even sometimes by extreme adduction of the femurs, so as to exercise a strain upon the round ligaments of the hip joint and rotator muscles, and thus pro- duce a direct outward traction. In this posi- tion of the bones, the action of the adult muscles which support the erect posture — viz., the great glutei and psoae, will be such as to increase the deformity (seeder. 122. E, c d), as well as those before mentioned which sustain the spine erect. If the angular deformity have been already impressed upon the infant pelvis by the bending of the cartilaginous junction, while the bones of the legs, and in some degree those PELVIS. 199 °f the pelvis, retain a sufficient degree of hard- ness to resist the bending, then the inward pressure of the heads of the femurs remains in its full force, associated with the upward and brickward pressure, and the deformity is increased by the upright position (Jig. 122. c, a b, a c). The same result is also produced in an increased degree, if the leg bones yield outwards, so as to direct the pressure of the heads of the thigh bones more towards the median line. This will be better understood by referring to the diagram (Jig- 122. D, a b, a c). Naegele observes, that when the lower extre- mities are curved and distorted the pelvis will generally be deformed ; and that such a con- dition more especially, or where one hip is higher than the other, with an unsteady gait, a projecting abdomen and lower jaw, and re- traction of the arms and thorax, diminutive stature, &c., should lead the accoucheur to suspect deformed pelvis.* The adult pelvis, softened by malacos- teon, appears to undergo greater distortion than is proportionate to that of the leg bones. In that upon which the experiments before mentioned, to ascertain the proportions of the osseous constituents, were performed, the bones of the lower extremities were almost entirely symmetrical and well formed, and the proportion of earthy matter contained in the femurs much greater than in the pelvic bones, especially in the pubes (at one point of which it was entirely deficient) and the sacrum. The pubes, as they are also the thinnest pieces of the innominate bones and sustain a great amount of the inward pressure, which exists, in these £ases, to its full extent, seem to be the first to give way in the more complete and rapid softening of " mollities ossiian adultorum" The consequence is, the approximation of the acetabular extremities, and increased curve of the cotylo-sacral arch, so as almost to touch the sunken sacral key-stone ; and the starting forward and upwards of the crown of the pu- bic counter-arch, so as to produce the rostrated symphysis. The muscles'before enumerated, which sup- port the erect posture, as they are in the adult more powerful and developed, have a corre- sponding effect in increasing the contraction of the diameters consequent on the distortion. The bones yield between their contracting dis- tances in the direction already impressed upon them. The acetabula are pressed backward by the psoae and iliacus muscles, and the ischial tuberosities and trochanters approxi- mated by the pressure of the great glutei, which, aided by the pyrifonnes, will also draw for- ward the lower part of the sacrum and coccyx. The powerful influence of the adult muscles upon the pelvic bones partially softened, and especially that of the great glutei upon those bounding the diameters of the inferior outlet, will produce many of the pa tial deformities before treated of, as the influence of mechan- ical posture in a limited extent, or short dura- tion of the softening disease, will produce others, principally those of the pelvic brim. * Lehrbuch, § 444, The peculiar variety of the partial deformity will depend upon the frequency of the use of one particular posture or set of muscles ; and this will depend chiefly, in the child, on the concurrent ailments which usually affect it, and in the adult on the nature of his or her habits and employment. The degree of the backward curvature of the cotylo-sacral arch seems to depend upon the degree of anterior lumbar curvature, which necessitates a forward projection of the femurs to keep the line of gravity between the feet (see/g. 122. E, a b). The rostrated pelvis, with elongated antero- posterior diameters, apparently results from the coincidence of the softened pubes with the causes of oblong deformity before adverted to, as produced by a backward spinal curve, causing the line of gravity to fall considerably behind the acetabula, and dragging backwards the superior part of the sacrum. The mechanism of these important pelvic deformities has been entered into more in detail because of the evident practical infer- ences which may be drawn from it with re- gard to the treatment and position of children, especially females, afflicted with rickety dis- ease. Degree of obstruction. — Pelves affected by the foregoing distortions are usually arranged by British obstetricians, according to the de- gree of obstruction at the brim, into three classes : — 1st. Those which will suffer the full-sized foetal head to pass entire. 2nd. Those through which delivery may be accomplished "per vias naturales" by means of premature labour, craniotoiny, or mutilation of the foetus. 3rd. Those in which the degree of defor- mity is so extensive as to call for the Caesarian section, or the very early induction of abor- tion. The limits of the first class have been va- riously stated by different obstetricians, accord- ing to their opinions regarding the obviou variations in size of the foetal head, and its de- gree of ossification. The following list conveys the opinions of the most eminent authorities upon the lowest limits through which the foetal head can pass entire : — DIAMETERS Conjugate. Transverse. Ramsbotham, Churchill Lee, and 7 „ . h . - most obstetricians - J ** Aitken and Osborne - - 3 „ „ sufficient. Jo-h. Clarke - - 3| „ „ Burns, Davis, and Le R i - - 3? „ „ „ Barlow (Essays) - - 2f „ „ „ Busch (Berlin) - - - 2$ to 3 „ Ritgen 2 „ „ The lowest limits of the second class of pelves involves a great difference of opinion as to the lowest space required for the safe performance of craniotomy : — Conjugate. Transverse. 1— ins. by 3a ins. Osborne, Hamilton, and Gardien - Davis and Barlow - Baudelocque - Burns, Hull, and Churchill Dewees or 1* „ ,, 3 „ 1* „ „ l^atinf. outlet. 2? ,',' ',' 3i ins. O 4 200 PELVIS. In these cases, according to Ramsbotham, it is rare that the transverse diameter does not exceed three inches. Less room is required if the brim alone be distorted, according to the same author. All pelves contracted in their diameters be- low the measurements given in the last list may undoubtedly be considered to require, for the delivery of a foetus of viable or full-grown size, the abdominal section. Dr. Robert Lee, however, advocates strong- ly, and with great justice, the propriety of inducing abortion in these deplorable cases, as a means of saving the life of the mo- ther. When the sacro-pubic diameter is below 1£ inch at the brim, this author considers that abortion should be induced before the fifth month. According to Ritgen, labour should be induced in the twenty- ninth week, when the sacro-pubic diameter is 2 inches 7 lines ; in the thirtieth week, when it is 2 inches 8 lines; in the thirty- first, when 2 inches 9 lines ; in the thirty- fifth, when 2 inches 10 lines ; in the thirty- sixth, when 2 inches 11 lines; and in the thirty- seventh, when exactly 3 inches. When above 3 inches, the case should be left to na- ture. Barlow thinks that premature labour should be induced when this diameter is con- tracted to 2i or 2£ inches.* But in many cases, especially on the Con- tinent, a much less degree of contraction of the conjugate diameter has been thought suf- ficient to justify the Csesarian operation. In a table given by Velpeanf, out of sixty-two cases where narrowness of the conjugate diameter was the reason adduced for adopt- ing this operation, in one case it was 1 inch only; in eight cases, 1£ inch; in twenty- three cases, 1£ to 2 inches ; in twenty-five cases, 2 to 2£ inches; and in five cases, 2£ to 2f inches. These, without doubt, in- clude many which the British practitioner would place in the first of the foregoing classes, and were adopted with a view of saving the child's life, at an additional risk to the mother. The "pelvis oblique ovata" or obliquely con- tracted pelvis. — This form of pelvic distortion was first distinguished and accurately described by Naegele,the distinguished Professor of Mid- wifery at Heidelberg, as possessing the follow- ing characteristics (scefg. 123.): — : 1. Complete ankylosis of one of the sacro- iliac joints, with coalescence of the sacrum and ilium, generally leaving no cicatrix nor line of junction. — 2. Arrest of development, contrac- tion of the lateral mass, and diminution of the foramina, on the ankylosed side of the sacrum. — 3. Narrowing of the innominate bone of the same side, shortening and also flattening of the linea innominata, contraction of the°sa- cro-sciatic notch by the ankylosis, and con- traction of the lateral parts of the sacrum and ilium composing the sacro-iliac junction. — 4*. Shifting of the sacrum towards the anky- * Essays, p. 354. f Traite des Accouchements, p. 457. losed side, and twisting of its anterior surface iu the same direction, together with removal of the pubic symphysis towards the opposite side, so as to be no longer placed in the median line opposite to the sacral promon- tory, but obliquely directed towards it ; a di- rect forward line from the promontory falling on the superior pubic ramus, between the symphysis and acetabulum, its distance from the former varying with the degree of distortion. The bodies of the lower lumbar vertebrae are also,moreor less, turned towards the ankylosed side. — 5 On the ankylosed side, the inner wall of the pelvis, both before and behind, is less excavated and flatter than in the normal pelvis. — 6. On the side free from ankylosis also, the form deviates from the normal shape, although at first sight it appears healthy. On placing together the corresponding non-ankylosed sides of two of these pelves, separated at the symphysis and in the median line, in which the right and left sacro-iliac joints respectively were ankylosed, Naegele found the pubic bones widely divergent from each other. So that, on this side also, these pelves are abnormal, not only in direction, but in form also, being curved less behind and more in front, than in the normal pelvis, — 7. From this it fol- lows, that the obliquely deformed pelvis is contracted Jn the diameter which extends from the normal sacro-iliac joint to the opposite acetabulum; while it is not con- tracted, but sometimes, according to the de- gree of distortion, even widened in the di- ameter, from the ankylosed joint to the acetabulum of its opposite side. The superior pelvic aperture thus presents the appearance of an oblique oval (or oblong), the longest diameter of which corresponds to one of the oblique pelvic diameters, and the shortest to the other oblique diameter. From this ap- pearance of the brim he was led to apply the name above given. That the sacro-cotyloid distance, and also that between the apex of the sacrum and the sciatic spine, is smaller on the ankylosed side than on the other. That the distances between the sciatic tuberosity of the ankylosed side, and the posterior superior iliac spine of the opposite side, and also be- tween the last lumbar spine and the anterior superior iliac spine of the ankylosed side, are less than the like measurements on the oppo- site side. That the distance between the lower border of the pubic symphysis and the posterior superior iliac spine, is greater on the ankylosed side than on the other. That the walls of the pelvic cavity converge towards the outlet in some degree in an oblique direc- tion, and the sub-pubic arch is more or less narrowed, and turned towards the thigh of the ankylosed side. That the contraction of the sa- crp-sciatic notch, and the approximation of the sciatic spines, is proportionate to the degree of distortion. And, lastly, that the acetabu- lum of the ankylosed side is directed more forward than normal, and the opposite one almost directly outward. In most cases, the sciatic tuberosity, and the acetabulum of the ankylosed side, were more elevated than the PELVIS. 201 opposing ones ; the ankylosed innominate bone appearing as if pushed upwards. A remarkable peculiarity of this deformity is, that, with the exception of the difference in the side where the ankylosis had taken place, the pelves affected with it were extremely like each other. The strength, texture, and ap- pearance of the bones were perfectly healthy ; there was no limping gait observed in the patients affected with it; nor any history of accident, rickets, or malacosteon. Examples. — Naegele collected, with incre- dible industry, notes of thirty-five examples of this disease in female pelves, and two in male pelves. Of these, two (one male and the other female) were in the collection of Pro- fessor Montgomery, of Dublin, and the others in the various collections of France, Germany, and Italy. In one case, which was observed during life by the author himself, he observed a slight halt in the gait of the patient, who otherwise was apparently well-built, healthy, and active. In her first labour, at the age of eighteen years, the foetal head in the early stage was found placed very high, and easily moveable, and the sacral promontory could not be reached by the finger. The patient was delivered, on the third day, with extreme difficulty by the aid of the forceps, and died fifteen days afterwards from puerperal fever. The pelvis was found affected with the oblique deformity, but in strength, weight, and texture perfectly healthy (fg. 123.). the sacrum was Fig. 123. Pelvis oblique ovata. (After Naegele.) composed of four pieces only, and measured in length 2 inches 11 lines. The coccyx had six pieces, and measured 1 inch 10 lines. The left sacro-iliac joint was ankylosed, and the same side of the sacrum was shrunk and con- tracted, so as to measure from the sacral pro- montory to the usual position of the sacro- iliac joint, only 1 inch 4- lines ; whereas the same measurement on the right side amounted to 2 inches 2 lines. The length of the left iliac crest was 3 lines less than that of the right. From the sacral promontory to the left superior anterior iliac spine measured only 3 inches 1 1 ^ lines. The same measure- ment on the right .«ide amounted to 5 inches 4 lines. At the brim of the pelvis the mea- surements were: — in. lines. From the sacral promontory to the upper border of the ob- liquely placed symphysis pu- bis - - - - 3 9 Left oblique diameter -47 Right, ditto, ditto - - 3 5 From the sacral promontory to left acetabulum - 1 10 From ditto to right acetabulum 3 6 A direct line drawn forward from the sacral promontory cut the left pubis at the junc- tion of its superior and inferior branches, an inch external to the centre of the pubic sym- physis. In the pelvic cavity the measurements were : — in. lines. From the centre of the sacrum, to that of pubic symphysis - 4 4 Between the cotyloid walls - 3 1 1 „ „ ischial spines - 2 ll£ At the outlet, the measurements were : — in. lines. Between the sciatic tuberosities 3 0 „ lower border of the pubic symphysis and apex of sacrum 4 4 The lowest oblique diameter in these pelves described by Naegele, was found in one in the Museum of the Hospital of St. Catherine at Milan, in which the left oblique diameter was 2 inches 10 lines only ; while the right was 4 inches 6 lines. In the same pelvis, the right sacro-cotyloid measured only 1 inch 8 lines ; and the left 3 inches 1 line. In one case, the left, and, in another, the right sacro-cotyloid diameter, was as low as 1 inch 6 lines. In one instance, the distance between the tip of the coccyx and the tuber ischii of the ankyloid side, was only 1 inch. The left side was the one most frequently affected by the ankylosis, but the right side was also found affected in many of the specimens, and, among others, in the pelvis of an Egyptian female mummy. In addition to the foregoing, three female pelves are described by the same author, in which the oblique deformity was present, but the diminution of the diameters not so great as to produce any great obstacle to parturition. One of these is in the Museum of St. Bar- tholomew's Hospital, and is rather above the medium size. The right side of the sacrum is imperfectly developed. The left oblique dia- meter is nearly 1 1 lines less than the right ; and the right sacro-cotyloid distance, 10i lines less than the left. A line drawn directly for- ward from the sacral promontory cuts the right pubis 1 inch external to the centre of the sym- physis ; and the distance from the sacral pro- montory to the symphysis is 4 inches 10£ lines. One of them, in Naegele'sown collection has six instead of five sacral pieces. In none of these three pelves, however, is there ankylosis of either of the sacro-iliac joints, although the imperfect development of one side of the sacrum is evident. In a male pelvis, on the contrary, there was 202 PELVIS. ankylosis of the right sacro-iliac joint, but no atrophy of that side of the sacrum, though the oblique deviation was present in a small degree, the right innominate bone being a little more elevated, contracted, and flattened than the left. The whole appearance of this pelvis bore somewhat a resemblance to that of an animal, and presented on the posterior part of the ex- ternal surface of each iliac wing a remarkable protuberant growth of bone, as well as an articulation by fibro-cartilage between the left lateral mass of the sacrum and the trans- verse process of the last lumbar vertebra, which was unusually large.* This last peculi- arity was also observed in an obliquely de- formed female pelvis in which both the last transverse processes were enlarged and bifur- cated ; the right being articulated by fibro- cartilage to the corresponding lateral mass of the sacrum, and the left (the side on which the sacro-iliac coalescence existed) similarly articulated to the inner surface of the ilium just above the sacro-iliac junction.-f* As a contrast to specimens like the two last, Naegele mentions a well-built female pelvis, in which the left lateral mass or side-piece of the sacrum was, by arrest of development, di- minished to the size and appearance of the last lumbar transverse process, but presenting an osseous protuberance, about the size of a bean, as if of the aborted ossific centre, while that on the right side was quite normal in size and appearance.^ He had seen two others similarly deformed, and mentioned examples in the collections of Sebastian at Groningen, and Vrolik at Amster- dam, and many more in the Pathological Mu- seum at Paris, and others mentioned by Creve and Retzius. Such irregularities of the sacrum are not uncommonly found. A young female pelvis is described by Dr. Knox § as presenting an example of the ob- liquely deformed pelvis in an earlier stage. The right half of the sacrum is more than half an inch narrower than the left, the first piece not ossified to the second, and the cor- responding half of the pelvic inlet proportion- ably smaller, the pubic symphysis being oppo- site the right sacral foramina; but the iliac portion of the innominate bone is tolerably symmetrical, and there is no sacro-iliac anky- losis. The lumbar vertebrae present an ex- tensive lateral curve. The same author also mentions that in Dr. Campbell's Museum there is a complete specimen of the obliquely ovate pelvis, deformed on the left side, and presenting a large exostosis on the last lumbar vertebra. In his own possession hehas portions of two other pelves, both exhibiting ankylosis of the sacro-iliac joint on the left side, but in one partial only, with twisting of the sacrum and contraction of the ilium, such as would pro- duce, if the specimens were entire, the oblique * Tafel xi. Das Schrag Verengte Beckon, t Num. 10., tafel iii. Op. cit. J Heidelberg Klin. Annal., vol. x. p. 4G8. § Med. Gazette, vol. xxxii. p. 537. deformity of M. Naegele. On looking over a collection of human bones taken from an old London graveyard, I have lately met with a well-marked specimen of this disease on the right side, in which there is a line or cicatrix at the sacro-iliac point of coalescence. From the many specimens which had come under his observation in so short a time, and with but few opportunities of seeing them, Naegele was led to conclude that this de- formity occurred pretty frequently. Its influence upon parturition will present an obstacle, not only to the forward progress of the foetal head, but also to its proper rota- tion, which will vary with the general extent of the pelvic diameters. If the pelvis be of large size, this deformity, though great, will have less influence than in a smaller pelvis, with a less degree of distortion. The foetal head may enter the brim with its long diameter in the long oblique diameter of the distorted pelvis ; but when in the pelvic cavity it will not be able to make the requisite turn into the antero-posterior diameter of the outlet, and will generally, in the opinion of Naegele, re- quire the use of the forceps to extract it. The obstruction occurs in the first labours, and its importance may be considered as equal to those resulting from rickets and malacos- teon, when it is considered, that in all the cases of labour hitherto published, where this deformity has been present, both mother and child have been lost, although in the hands of the most experienced accoucheurs. The diagnosis of the oblique distortion by the usual measurements is very difficult. It is rendered still more difficult by the absence of any history or peculiar appearance of the patient, indicative of the condition of the pel- vis ; persons affected with it being usually, in other respects, well built and healthy. The diagnosis, moreover, is usually called for in first labours. The promontory of the sacrum is not to be felt by the finger, an usual indication of plenty of room at the brim ; and yet there may be sufficient contraction in the oblique or sacro-cotyloid diameters, to require the Caesarian section. The antero-posterior diameter, which would show, if a section were made in the centres of the sacral-promontory and pubic symphysis, a clear space of 3£ to 4? inches, may appear, in the living subject, to be contracted to!2i inches. The contraction of this distortion is as totally unrecognisable by the use of Baudelocque's calipers, which may lead to gross error. The amount, in the well-formed female, of the measurements instituted by Naegele for the purpose of ascertaining the presence of this deformity upon the living subject, have been given in a former section of this article. The results of the measurements of eight female pelves obliquely deformed, in five of which the ankylosed joint was that of the left side, gave the following differences in measure- ment between the two sides. PELVIS. 203 Extremes of dif- ference between the two sides. 1. From the sciatic tuberosity ofl ffQm l to one side to the posterior su- }• 9 • i • ... • /* l_ U. I *^ IIJLIICO* penor iliac spine ot the other J 2. From the anterior superior iliac"] from JO spine of one side to the pos- Mines to 1 terior superior of the other J in. 1 1 lin. 3. From the spine of the last lum-1 from 8 bar vertebra to the anterior > lines to 1 superior iliac spine J in. 4 lines. 4. From the trochanter major oH from 1 in. one side to the posterior su- > to 1 in. penor iliac spine of the other J 7 lines. 5. From the lower border of the~| from 7 pubic symphysis to the pos- >- lines to 1 terior superior iliac spine J inch. In these measurements it is to be remarked, that the first presents the most marked dif- ferences on the two sides. This results from the fact that the sciatic tuberosity of the an- kylosed side is placed more posteriorly than the ^opposite one, while the posterior supe- rior iliac spine is lower on the side free from ankylosis. Hence it results that the ankylosis is always found on that side of which the sciatic tuberosity is nearer to the opposite posterior su- perior iliac spine. These two points on a lean subject are easily to be distinguished. On the fat subject, there is, in the position of the iliac spine, a depression caused by the firmer attach- ment of the integuments to the bone at that place. Another test of the presence of the ob- lique deformity practised by Naegele was, to place the patient upright with the back against an even wall, so that the shoulders and nates should equally touch it, and then drop- ping two plumb-lines, one from the spine of the first sacral or last lumbar vertebra, and the other from the centre of the lower border of the pubic symphysis. In the well-formed pel- vis, the plane in which these two lines fall, forms two right angles with the plane of the wall, but in the pelvis obliquely deformed, it is an obtuse angle on the ankylosed side, and an acute angle on the side opposite ; the dif- ference between these two angles marking the degree of distortion. Cause of the obliquely deformed pelvis. — Dr. Naegele was inclined to the opinion that the cause of this peculiar condition of the pelvis was, an arrest of development of one side of the sacrum and the corresponding in- nominate bone ; with ossification of the joint instead of its normal development. The following reasons led him to this conclusion. The intimate and complete fusion of the bones into one piece ; and the absence of any mark or cicatrix indicating a former separa- tion, except a sca-cely perceptible line on the upper aspect of the place of junction ; a section of the ankylosis exhibiting an uniform areolar texture in the internal structure. The defective development, in its whole length, of the ankylosed side and lateral mass of the sacrum, as well as of the innominate bone in breadth, as particularly exhibited in the narrowing of the sciatic notch ; and the analogy herein drawn, from the defective de- velopment and fusion of other bones, especi- ally those of the cranium. The great re- semblance between the several pelves affected by this disease, which argues identity of cause ; original deficiency of development being more likely to produce similarity of results than the accidental and subsequent inflammation. And lastly, the presence of the distortion from the earliest period, together with the youth of the individuals affected, and the total absence of any symptoms whatever, indicating an ex- ternal cause for the distortion, in the whole course of their history. In two of the cases of this deformity, there had been present disease of the hip joint, which in one had led to the formation of a false acetabulum ; but this was not, in the opinion of the above-named author, the cause of the oblique distortion. He had never seen the distortion coincident with rickets, though he suggests the possibility of such a compli- cation. Rokitansky also considers this deformity to be a congenital malformation, and not a consequence of foetal intra-uterine disease. Dr. Knox adopts the theory that the arrest of development having taken place while the ossification of the sacrum was in- complete, the whole of that side of die pelvis remains thereafter stationary in its foetal or brute transitional form, while the other ad- vances to complete development ; and thus one side is perfect, while the opposite is simply that of an undeveloped pelvis magnified. This 'anatomist also states, that in the mu- seum of Dr. Outrepont there is a female pelvis presenting the oblique deformity on both sides, producing a superior opening of a very elongated shape, with its broadest part towards the sacrum. The lateral epiphysial sacral pieces, which form the auricular surface, appear in the ob- lique deformity to have failed in establishing a separate identity, though the presence of the sacral holes and transverse lines and grooves lead to the supposition that the number of the primary ossific points has been normal. Un- der this supposition, the coalescence of the sacrum and ilium would, probably, take place between the sixth and ninth months of intra- uterine life, (at which time the characteristic ossific points of the three first sacral vertebrae begin to appear,) by the prolongation into them of the ossifying process from the ilium or " pleurapophysis," already considerably ad- vanced in its bony development. Another hypothesis as to the cause of the ankylosis. is found in the occurrence of in- flammatory disorganisation, after the com- plete formation of the sacro-iliac joint, and, as a consequence, oblique deformity of the bones. Dr. Kigby inclines to this theory, and thinks that ulcerative absorption must have existed in the joint, though probably in early- life. 804. PELVIS. Since we know that the foetus in utero is subject to similar pathological changes to those of childhood, it seems probable that a modi- fication of the two theories may be the true statement of the origin of this formation — viz., an occurrence of inflammation and the patho- logical changes usually consequent upon this process in joints — such as ankylosis, happening at a period of immaturity, coincident with, or consequent upon, an arrest of development in the structures implicated, and probably having the same ultimate cause. The three cases before quoted from Naegele, in which the deficiency of the sacrum and the oblique deformity existed, but without the ankylosis, and on the other hand, the many cases in which we have ankylosis on one or both sides with- out the oblique deformity, show that the two conditions may occur separately and indepen- dently of each other. These cases also prove beyond a doubt, that the sacro-iliac ankylosis of itself does not produce the deformity ; and, moreover, that it is not absolutely an essen- tial, although a frequent accompaniment of this peculiar formation. A third supposition alluded to by Naegele, that the ankylosis and oblique distortion is caused by increased pressure from the lateral divergence of the vertebral curve in early youth, seems to be contravened by the fact, that such a pressure does not produce such a result in the many instances of other pelvic deformities. The tendency to an unsym- metrical one-sided distortion in the instances before alluded to, presents many differences to, and more variations of form than, the defor- mity under consideration. The mechanism of this deformity in re- spect to the line of gravity of the body fall- ing nearer to the acetabulum of the anky- losed side, and so throwing the weight of the body more on to the corresponding leg than on its fellow, will present some similarities to that of the one-sided pelvis just mentioned; with this exception, that the bones of the obliquely ovate pelvis are healthy and not softened, and that the lateral pelvic arch is, consequently, flattened only, and not indented, the principal yielding and inward bend appear- ing to take place at the abnormal sacro-iliac junction, and thus the antero-posterior dia- meter— i.e. from the sacral promontory to the pubic symphysis — is increased and not dimi- nished. Another form of unsymmetrical pelvis is described by Rokitansky, arising from a coa- lescence of the base of the sacrum with the body and transverse process of the last lum- bar vertebra, on one side the median line only, and the participation of the latter in the for- mation of the sacro-iliac joint on that side. The innominate bone thus obtains a higher degree of elevation, and a greater inclination to the spine, and describes a larger and shal- lower curve of the "linea innominata"than its fellow. The conjugate diameter is rendered greater, and there is a larger capacity on the abnormal side of the pelvic cavity. There is but slight projection of the sacral promontory, and the lumbar vertebras are rotated, and their curve inclines to the opposite or smaller side, and may thus produce a lateral compensating curve in the thoracic region. In this latter particular, also, this form of pelvic distortion differs from that described by Naegele, in which the lumbar curve is towards the abnormal side. I have met with two pelves presenting this abnormality. In one, that of a female, which is in the collection of Dr. A. Farre (fig. 124.) Fig. 124. Oblique pelvis from sacro-lumbar coalescence. the left half of the sacral base is ankylosecl to the corresponding side of the body and trans- verse process of the last lumbar vertebra, which are flattened and enlarged so as to as- sume the form of the first sacral, leaving a hole for the transmission of the last lumbar nerve. The lumbar transverse process of the opposite side is bifurcated, the lower division being attached by ligament to the venter ilii ; and the corresponding half of the sacro-lum- bar fibro cartilage remains unossified. The last lumbar spine and laminae are connected with the sacrum by very thin plates of bone, but preserve their own distinct outline. There is no ankylosis of the sacro-iliac or lumbo-iliac joints. The true sacral promontory projects little, but a prominent false one is formed by the last lumbar vertebra. The sacrum is short and small, but presents four distinct sacral holes, and five pieces. The lower part of the sacrum presents an abrupt forward curve, so as to leave, with the shortness of the whole bone, little room for a foetal head, which would, probably, require craniotomy in such a pelvis. There is a slight lumbar curve to the right or opposite side to the lumbar ab- normality. The pubic symphysis, also, is re- moved about i or » of an inch to the right of the median line. The other pelvis is that of a male, in the Museum of King's College. In this pelvis, there is complete ankylosis of both the proper sacro-iliac joints, preserving behind pretty much the outline of the sacro-iliac ligaments ; and partial ankylosis of the abnormal lumbo- iliac junction, which is also on 'the left side. The true sacrum is large and well formed, and the posterior crest is connected with the last lumbar spine by a thin plate of bone. There is, apparently, no lateral spinal curve in this specimen. PELVIS. 205 Whether these pelves and those mentioned by Rokitansky are not similar to those de- scribed by Naegele as arrest of development of one side of the first sacral bone, is a question which can only be decided by ab- solute comparison of the specimens. A greater or more advanced development of one side of the pelvis than the other is said bv Knox, in a memoir " On the Statistics of Hernia," to be frequently seen, and to pro- duce a greater predisposition to hernia on that side. The author considers it as the result of a similar want of balance between the development of the lateral halves of the pelvis to that seen, in a greater degree, in the "pelvis oblique ouata" and which is also often seen between that of the true and false pelvis. Pelvis obstructed by exostosis. — Exostoses projecting from the pelvic bones most usually proceed from their internal surfaces, in which position they are also of more serious im- portance in producing obstruction to parturi- tion in the female. According to Ramsbotham, it is a rare condition of the pelvis, he having never seen an instance. Exostoses are most frequently found at the back part of the pelvic cavity, growing from the sacrum, near the sacro-iliac joint, or, according to Lever, at the last sacral piece. They are, however, by no means confined to these positions. Many instances of this disease have been recorded, in which the diagnosis has not been verified by post-mortem examination ; and it is doubtful whether many of them were not projections of the sacral promontory and lumbar vertebrae, as in a case described by Nagelin the Frankfurter Zeitung (April, 1778). It has been observed in the male as well as in the female pelvis. One of the most remarkable cases of ex- ostosis of the sacrum, producing obstruction to parturition, occurred to Dr. Haber, and is recorded in Naegele's Inaugural Disser- tation, published at Heidelberg in 1830. The disease was said to have followed a fall while the woman was carrying a load on her head, and which was followed by pains in the back and pelvis. On afterwards becoming pregnant, the whole of the pelvic cavity was found to be filled by a bony tumour growing from the upper part of the sacrum. The Caesarian section was performed ; and the patient died soon afterwards. The tumour was found to be 7 inches long by 6 in. broad, reaching as hi«h as the junction of the 3rd and 4th" lumbar vertebrae and as low as from about 2^ lines from the apex of the sacrum. Between it and the posterior surface of the pubes there was a space of 8 or 10 lines in one part, but only a line and a half in another, the mass thus filling up nearly the whole of the pelvic brim. A section of the tumour showed large cells in the interior, communi- cating freely with the sacral areolae. Another remarkable case is recorded in the Edin. Med. and Surg. Journal (April, 1831), for which hysterotomy was performed by Dr. M'Kibbin, Surgeon to the Lying-in Hospital, Belfast. The patient had suffered a fall on the back when about six or eight years of age, which was followed by pains in the sacral region for a short time afterwards. The ex- ostosis was of a conical form, with the base at the sacrum (see^g. 125.), and occupying its whole breadth at about the four lower sacral pieces, its apex projecting towards the pubis, and leaving a space of only 1£ inch between it and the lower part of the pubic Fig. 125. Exostosis of the sacrum. symphysis. The greatest space was left op- posite the superior ramus of the right pubis, where the distance of the tumour from the pubic wall was from 1J to If inches, but di- minished posteriorly. The patient died soon after the operation ; nor was the child saved. A less formidable case came under Dr. Murphy's observation. The tumour was about the size of an orange, and was connected to the sacrum about its middle. It was quite immoveable, and of bony hardness. The pa- tient being in labour, craniotomy was per- formed ; and the case did well. Another case is recorded by Van Doevern, of an osseous tumour, of the size of half a hen's egg, grow- ing from the upper piece of the sacrum, and causing the death of both mother and child. Dr. Kyle, of Cologne, met with a case of a woman who had borne seven children with great ease ; but at the eighth labour the foetal head became impacted by a hard immoveable tumour, as big as a hen's egg, springing from the upper part of the right sacro-iliac joint, being apparently the result of a pelvic abscess after the last delivery, which had, three years before, opened in the groin. Dr. Lever has seen but one case of pelvic exostosis. It occurred in'an unmarried female lunatic, and grew from the posterior surface of the pubis, producing retention of urine.* Las- sus describes processes of bone, of a styloid shape, projecting from the posterior surface of the pubis towards the bladder.f These resulted, apparently, from ossification of the anterior ligaments of that viscus. Besides these, an exostosis is mentioned by Velpeau (Tocologie), protruding from the posterior surface of the right pubis, and of the size of a hen's egg a little flattened ; and others by Pinaeus, Ruleau, and Portal, from an anky- losed symphysis pubis. One is alluded to by Naegele, which was as * Guy's Hospital Reports, Xo. 14, April, 1842. , \ Pathologic Chirurgicale (Paris, 1805, chap. 80.). 206 PELVIS. large as a filbert, projecting from the isckium into the pelvic cavity; and others in the same situation by Dr. Campbell and Otto of Breslau, in which indentation of the foetal head was produced. Other cases are found in Siebold's Journal and Gardien's Traite. Dr. A. Farre informs me that an osseous exudation from the anterior surface of the sacrum, consequent upon disease of that bone, had recently occurred in his practice, and compelled him to have recourse to craniotomy to accomplish delivery. Osseous projections at or near the sacro-iliac joints are also men- tioned by Kokitansky, and are to be met with in most museums of pathology. In a large female pelvis, in the King's College museum, is a small exostosis or spinous projection at the angle of the left sacro-iliac joint, in such a position as would produce an impediment to labour in a smaller pelvis. In the Hunterian Museum are two more specimens of this kind, both on the sacro-iliac joint, one in a male, and the other in a female pelvis. Many such exostoses are seen in the subjects brought to the anatomical rooms. They seem to have the same origin as the rheumatic bony projections which are so frequently met with, in old people, in the neighbourhood of the joints, but especially in those of the spine, hip, and shoulder. Rheumatic and gouty patients seem to be predisposed to exostosis. The influence of such exostoses upon par- turition approaches closely to that of deformed pelvis, in the contraction of the diameters and the danger or impossibility of their removal. The difficulty of distinguishing them, when of considerable size, from pelvic deformities, is sometimes very great. Their hardness is not so characteristic as to mark them from the pro- jections of the sacral promontory; their shape, compared with external measurements and the history and appearance of the patient are the chief means of diagnosis. Osteo-sarcomatous tumours sometimes pro- duce pelvic obstruction, and generally grow from the joints or ligaments. One case oc- curred to Grimmell o^ Kisbaden. and is re- corded in a letter to Naegele (Dec. 1835). Caesarian section was performed in conse- quence of a tumour of this kind, weighing li lb., attached to the periosteum only of the right sciatic spinous process and wall of the corresponding acetabulum. It had followed a fall, which had been succeeded by pains in the sacrum, a sense of weight in the right thigh, and ischuria. Stark performed hys- terotomy successfully for a tumour attached to the lower sacral vertebrae and innominate bone. It was immoveable, but soft in various parts, as well as could be detected "per va- ginam" This characteristic will distinguish these tumours, in diagnosis, from exostosis ; their partial hardness, from fibrous tumours ; their immobility, from tumours of the soft parts ; and their attachments to the side of the pelvis, from the foetal head. Obstructions from fibrous tumours attached to the pelvic ligaments. These are of rare occurrence, and have been found chiefly con- nected with the sacro-sciatic ligaments. The most remarkable examples are those re- lated by Dr. Drew in the Edin. Med. and Surg. Journal for 1805 (vol. i. p. 20 ). The first of these tumours was taken from the body of a woman, who had died in consequence of its pressure upon the pelvic viscera. It was 16 inches in circumference, of a hard, gristly tex- ture, with no appearance of vascularity, and was attached by a strong root, of the same texture, to the left sacro-sciatic ligaments, and interposed between the bones and viscera, but with no other attachment to the sur- rounding parts. The second tumour was ex- cised by Dr. Drew, by a formidable operation, from the pelvis of a woman in labour, who was afterwards safely delivered and recovered perfectly well and very speedily. The tumour was 14 inches in circumference, and weighed 2 Ibs. 8 ounces. It grew from the right side, and filled the whole cavity of the pelvis so com- pletely as to admit of one finger only being passed between it and the pubis, considerably interfering with the neck of the bladder and urethra. It was separated easily from the circumjacent tissues. A somewhat similar case is related by Dr. Burns ; but, in this instance, the attachments of the tumour were much more extensive ; reaching from the pubic symphysis to the sacrum, and adhering intimately to the pelvic brim, being attached also to the obturator internus muscle, urethra, vagina and rectum, and apparently developed in the recto-vesical fascia. It was hard, somewhat irregular, and scarcely moveable. The patient being in labour, Dr. Burns, by a bold operation, in which but little blood was lost, removed the tumour, which required to be almost dis- sected out. The woman was soon after safely delivered of a still-born child, and, after some peritoneal inflammation, recovered. Fibrous tumours attached to the pelvic pa- rietes are distinguished from the foetal head and tumours of the soft parts, by the immo- bility of their attachments ; from exostoses, by their want of bony hardness ; and from os- teo-sarcomatous tumours, by their uniformity of structure to the sense of touch. Carcinomatous growths commonly affect the bones of the pelvis, by advancing from the contained viscera, the uterus, rectum or ova- ries. Dr. A. Farre mentioned to me a case in which the innominate bones were so much infiltrated by cancerous matter, from a tumour commencing in the uterus, that they could, with great ease, be cut with the knife, pre- senting a condition very similar to the bones affected with mollities ossium. PATHOLOGY OF THE PELVIC JOINTS. — The pelvic joints, like all other joints in the body, but much less frequently than many, are subject to inflammation and its conse- quences in such structures — viz., ulceration, suppuration, and ankylosis. They are also, probably more frequently, subject to original malformation, coalescence, and anomalous constructions of a congenital origin. PELVIS. 207 Ankylosis is the most frequently seen in the sacro-coccygeal joint. It is also met with in the sacro-iliac, and sometimes, but most rarely, in the pubic symphysis. Anky- losis of the coccyx is one cause of pelvic ob- struction and protracted labour, and as such has been before adverted to. Meckel de- scribes ankylosis of the coccyx to" be more frequent in males than in females, particularly in such as have long-continued equestrian habits. Coalescence of the bones composing the sacro- lumbar articulations have been before described as producing deformed pelvis. This formation almost universally results from an original aberration of development, and not from ankylosis as a subsequent pathological result. Sometimes it occurs on both sides with hypertrophy and transformation of the last lumbar transverse process. In many of the instances recorded of six sacral pieces, and in the pelvis drawn after Murphy (see fig. 113.), a complete coalescence of this kind probably existed. Ossification of the sacro-iliac joint has also been referred to in connection with the "pelvis oblique ovata." It is, however, by no means confined to pelves presenting that deformity. In the Museum of King's College is a well- formed male pelvis, with ankylosis of the sacro-iliac joint on the left side, the bones presenting no other traces of disease or de- formity. In the experience of Rokitansky, it is rare that the bony union in ankylosis of the pelvic joints extends through the whole of the op- posed articulating surfaces, but generally takes place by bridge-like processes, passing from one margin of the joint surface to the opposing margin, so as to enclose the fibro- cartilage in a kind of bony capsule. It is not ascertained whether the fibro-cartilage itself ossifies, or, as he thinks is most likely, be- comes absorbed before the ossifying process from the adjacent bones. This author does not mention whether this process takes place without previous inflammation, or follows the analogy of other joints, in which pain, inflam- mation and absorption of the cartilages, usually precede the ankylosis. The instances of in- complete ossific union mentioned by him to be most common have most probably a rheu- matic origin, like the smaller exostoses pre- viously referred to, and arise from os-sific deposits in the circumferential ligaments, with- out the interior structures being affected. Meckel describes ossification of the sacro- iliac joints as those most frequently seen, and that it most commonly occurs on the rig/it side, and is to be accounted for by the greater pressure borne upon the right leg! He con- siders, also, that ossifications of this joint usually take place without preceding inflam- mation, from a gradual change in their sub- stance and in the fibrous tissues around them. In a specimen ofmkjtoaeApnbicgymptytu described by J. P. Mitchell, and given by Hull in his 2nd Letter, the whole of the fibro- cartilaginous disc wis converted into a smooth equable bony substance. A few other cases of complete ankylosis of this symphysis are recorded by Wagner. In a case described and figured by Sandifort*, the pubes were united on^ their posterior and upper surfaces by an osseous bridge in the position of the ligaments, leaving a chink between the bones in front. In the same pelvis the right ob- turator membrane was also extensively ossified, as well as a considerable portion of the right capsular ligament of the hip joint, — all these circumstances indicating a rheumatic origin. Ossification of the Kgamentum arcuatum is also mentioned as sometimes interfering with the urethra. Cases of imperfect ankylosis of the pubic joint are also mentione'd by Siebold, Voigtel, Walter, and Bonnard.f All writers agree that ankylosis of this joint is rare. Dr W. Hunter had never seen an instance of it. Ossification of the sacro-sciatic ligaments is mentioned by Meckel as sometimes exist- ing, and even more commonly than that of the pubic symphysis. Such a condition, if present in the female during parturition, would offer great obstruction to the passage of the head through the inferior strait, from its unyielding nature, and resistance to the extension of the coccyx. It is, however, not sufficiently common to be enumerated as one of the ordinary obstacles to parturition. A different result of inflammatory change in the pelvic joints, is that which gives rise to the separation of the bones at their articular surfaces. This, as a pathological process, takes place most frequently by deposits of pus, as a consequence of puerpal fever, which may entirely destroy -the joint, and separate the bones. From its more exposed position and more open structure, this change has been most frequently observed in the symphvsis pubis. A case of this kind is described" by Dr. W. Hunter, and many others have been observed. A more remarkable separation of the pelvic joints is to be ascribed to a congenital origin. It is one in which the pubic bones and with them, in a minor degree, the sacro-iliac auri- cular surfaces, are separated, mere or less widely, and held together by a ligamentous band. Instances in which this occurs to the extent of a third of an inch, are mentioned by Professor Otto, as being pretty frequent.J Probably one of the most extreme cases of this kind is seen in a preparation at present in the Hunterian Museum. It is the pelvis of a woman, which was presented, as I am in- formed, by Mr. Mayo, of Winchester, and taken from a case which died in the infir- mary of that town. The pubes are separated to the great distance of 4f inches; and con- nected by a ligamentous band of about the width, in its present dried state, of from i to ^ of an inch. The pubes are more ele- vated than normal, with their articular ex- tremities turned outward, and the symphy- * Observ. Anat. Path., b. i. p. 115., tab. 8. t Journal de Med. de Paris, 1778. t. xxxix. p.433. J Compend. of Human and Comp. Anatomy. 208 PELVIS. sial surfaces forwards, by the action of the adductors and obturator externus. The lateral curvature of the sacrum is consider- ably flattened out, and also the cotylo-sa- cral rib of the ilium. The sacro-iliac joints are each opened in front, for the space of about half an inch, stretching the anterior ligaments. The great space between the pubes is evidently obtained by the flattening of the linea inno- minata, as well as by the shortening of the innominate bones, in breadth, and their abnor- mal vertical or wall-sided position. The resulting diameters are ; — antero-posterior, from the sacral promontory to the inter-pubic ligament, 4- inches ; the inter- cotyloid, 6£ inches ; and between the sciatic tuberosities, 6^ inches. This condition, according to Meckel, is rarely met with without an analogous con- genital fissure in the bladder and walls of the abdomen. Walter, however, mentions one case. * Other congenital abnormalities of the pelvic bones are mentioned by Otto and Rokitansky. In the siren formation, the coccyx and lower extremities are entirely wanting, and the lateral parts of the pelvic bones are fused together, the outlet of the pelvis being nearly completely closed, and the parts presenting the appearance of the pelvis as we have seen it in the Cetaceans and Fishes. Their deve- lopment seems to have been arrested at that period of foetal life in which this condi- tion is normally, though transitorily, present. In some monstrosities, the sacrum also is wanting, or one or both the innominate bones, with the correspondig lower extremities ; or these parts may be stunted or coalesced. Influence of hip-joint disease upon the pelvis. — Caries and necrosis of the pelvic bones, although sometimes resulting idiopathically, or from bedsores and abscesses in the muscular sheaths or lymphatics, }ret chiefly occur as the consequences of coxa/gia, and have a tubercu- lar origin. The formation of false acetabula and the other pathological results of this di- sease or accidental malposition belong more especially to the pathology of the Hip-joint. A preparation of one of these in the Hun- terian Museum may be, however, appropriately described in this place, inasmuch as it would produce, if occurring in a parturient female, an obstruction to the foetal head, analogous to an exostosis. The head of the femur has become displaced into the obturator foramen, and about it an osseous deposit has taken place, apparently in the obturator membrane, which forms a smooth dome-like projection into the pelvic cavity, corresponding in size to the head of the femur. The subject is a male one, and the carious and light condition of the bones and the irregular ossific projections, indicate the results of disease. An interesting change in the position of the pelvic bones after hip-joint disease, is de- scribed by Rokitansky. f * Von der Spaltung der Schambeine. Berlin, 1782. f Pathological Anatomy, p. 259. Sydenham Society's translation. The dislocation of the femur upwards, which is commonly the result of coxalgia, is followed by a wasting of the innominate bones, especi- ally of the ilium. They assume a more ver- tical direction, and, at the same time, their inclination to the spine, as well as the lumbar curve, is considerably increased. If this condition be present on both sides, there is general enlargement of the pelvic cavity, due partly — to a general attenuation of the bones, causing the disappearance of the projections at the pectineal eminences, the sacro-iliac joints and the cotyloid walls, and partly to a flattening out of the linea in- nominate. The ischia become dragged out- wards and separated, the pelvic cavity shal- lower, and the sub-pubic angle more obtuse. The last result is attributed by Hiilshof to the dragging of the rotator muscles, from the displaced femur on the sciatic tuberosities, upon which the support of the trunk mainly falls in this condition of the joint. In the pelvis of a woman mentioned by Dr. Hull, however, in whom both the femurs had been dislocated backwards, the transverse diameter of the brim was diminished to 4£ inches, and the antero- posterior diameter of the outlet was diminished to only 2 inches, from the tilting forward of the lower part of the sacrum, or rather pro- bably, from the turning of the lower part of the innominate bones backward by the dis- placed femurs, acting on the axis of the sacro- iliac joints. If the disease be one-sided only, as is most commonly the case, and the diseased joint be much used, the tuber isc/iii of that side becomes everted, the innominate bone bent outwards, the distance from the pubic sym- physis to the anterior superior iliac spine lessened, and that side of the pelvic cavity enlarged. The pelvic cavity is, on the other hand, contracted on the sound side, towards which also the spinal curvature inclines, from the principal support of the body falling on that side. When ankylosis has taken place, the innominate bone is bent outward at the acetabulum, in the osseous cicatrix ; the ilium is placed more inwards and forwards, and the ischium inwards and backwards ; and while the pubic symphysis is drawn towards the diseased side, the sacral promontory is turned to the healthy side of the pelvis. In some instances, the pelvic inclination is less, instead of greater, on the diseased side, which is also raised higher than the other. This variation is attributed by Guerin to the action of the psoas and iliacus muscles, which sometimes in these cases impress a deep furrow upon the iliac wings, over the edge of which they play. There is no doubt, that the posture to which the patient may have been most ac- customed, has a great effect in producing such differences, as already explained in the fore- going pages. FRACTURF.S AND DISLOCATIONS ofthepelvic bones. — The sacrum, according to Boyer,is less frequently found fractured than the other pelvic bones, because of its .thickness, strength, PELVIS. 209 spongy texture, and deep-seated position. When fractures of this bone do happen, they are most commonly found at the lower part, which is less protected by the above pecu- liarities. They occur chiefly from direct and great violence, which generally injures also other parts of the pelvis extensively, seriously affecting the nerves of the sacral plexus, so as to produce paraplegia and retention of urine, as well as extensive injury to the soft parts, such as result in effusion of blood, peritonitis, and sloughing of the integuments. Fractures at the lower part are much more easy to diagnose than those of the upper, which are seldom discovered till after death. In the former case, the lower fragment is generally drawn forwards by the action of the great glutei and coccygei muscles, so as to press upon and interfere with the functions of the rectum, through which it may be felt by the finger. It will also produce great pain on moving the legs, which may lead to its discovery, when more serious injury is not present. The coccyx when normally placed is rarely fractured, on account of its great mobility and small size. It always happens by di- rect violence. When ankylosed, it is more frequently broken, and instances of this have been before mentioned, in relation to the obstruction of the outlet in parturition which it occasions. It is diagnosed by the mo- bility and grating of the fragments, and by the pain caused by the action of the great glutei muscles. Dislocation of the coccyx is said to have occurred backward in difficult labours, and to have been followed by abscess, but these cases have been most probably fractures like those just mentioned. Fractures of the innominate done generally occur on one side only, where the greatest part of the force has fallen, but sometimes on both. They are most frequently found in the ilium — which is most exposed, but often impli- cate both the ischium and pubes. They may be confined to one part of the bone ; in which case they are found chiefly about the iliac crest and wing. Boyer relates a case in which the inferior anterior iliac spine was broken off by the kick of a horse. Cases are not un- frequently seen where the anterior superior iliac spine and a portion of the crest are broken off. Sometimes they are comminuted in, and radiate from, the cotyloid cavity, such fractures generally resulting from direct vio- lence against the lateral pelvic arch, and act- ing on the head of the femur so as to drive it inwards through the pelvic wall. Fractures of the pelvis, like those of the spinal column, are seldom present without dis- location also of the sacro-iliac or pubic joints. This results from the circular arrangement of its bones, and from the laws of its mechanism, explained in the first section of this article. Thus, when force is applied so as to compress the pelvic circle from before backward (as commonly the cause of these fractures is such compression by the wheels of a loaded cart or other vehicle), then the cotylo-sacral arch Sit pp. yields inwards at its haunches, — the sacro-iliac joints, the anterior ligaments of which are torn, and the articular surfaces separated in front. At the same time the pubic tie yields either at the symphysi.s or in the superior rami. The innominate bone may be entirely dis- located upward or backward, generally on one side only. A case is related by Cloquet, in which this was the case on both sides, the pubic symphysis, at the same time, separated £ an inch, the pubis and ischio-pubic ramus were broken, and the bladder ruptured. Another case, where the left innominate bone was dis- placed upwards, was treated successfully by Chaussier. The ligaments and fibro-cartilage of the sym- physis pubis are usually torn, the latter ge- nerally carrying with it a portion of one of the bones ; or the superior ramus is broken at its weakest part, above the obturator fora- men, or it separates from the other innominate pieces. In most cases the ischio-pubic ramus of the same side also yields at or near the point of suture, which is its thinnest and weakest part, and the obturator foramen is again penetrated. This results from the ope- ration of the force upon the unsupported ischio-sacral arch and its tie, after the other has yielded. A preparation exhibiting such a fracture is found in the King's College Mu- seum. In this case the superior pubic ramus has separated in the acetabulum from the other pieces of the innominatum in the line of the Y-shaped suture, while the fracture through the ischio-pubic ramus extends up- wards, along the side, and into the centre of the pubic symphysis (fig. 126.). Fig. 126. Fracture of the pubis and acetabulum. This fracture, accompanied by that of the superior pubic ramus, may also happen from a fall from a great height upon the breech, on one side or both, as the force happens to fall. The great strength of the body of the ischium renders a fracture there of less frequent oc- currence than in the other pieces of the innoimnatum. Fractures of the innominate bones seldom occur without displacement, produced usually — not by subsequent muscular action, which is kept in check by their balance of power, and by the extensive ligamentous and fascial at- •210 PELVIS. tachments and the opposing fractured sur- faces,— but by the original direct violence. By such displacement of comminuted and spicular fragments in the true pelvis, the bladder and urethra, particularly if the former be distended at the time of the accident, often suffer great laceration, which may even extend to the peritoneal investments and open the cavity of the abdomen. Such extensive injuries are invariably followed by extravasa- tion of the urine into the pelvic areolar struc- tures or peritoneal sac ; and violent peritonitis carries off* the patient, even if he survive the first shock of such a formidable accident. The external soft parts, also, generally suffer greatly from the violence, and from the great extravasation of blood which usually takes place from the torn vessels. Gangrene may, in these cases, succeed to a great extent, and destroy the patient. It is these injuries, and their consequences to the soft parts and in- ternal structures, that render fracture of the pelvis, like those of the cranium, so dangerous and fatal to life. The diagnosis is drawn from the pain and difficulty of moving the lower extremities, and from the mobility and crepitus of the fragments, felt on placing the hand on the iliac crest, the pubic spine, and sciatic tu- berosity consecutively and moving the leg. The crepitus is most distinctly felt by the hand which rests on the pelvic bones, and scarcely at all by that which moves the leg. This useful comparison will distinguish these fractures from those of the neck of the femur. If one ilium be dislocated upward and back- wards on the sacrum, and at the same time separated from the other bones by a fractured acetabulum, the femur is drawn up with the ilium, the trochanter turned forwards, the knee and foot turned inwards, and the whole limb shortened, so as to resemble a dislocation at the hip-joint. Deeply-seated fractures, however, often pass undetected, from the rigid contraction of the muscles, the great pain experienced on motion, and fear of in- juring the viscera more extensively. They will be more easy to detect on the thin subject, and on the female. In one of the cases figured and related by Sir Astley Cooper in his Surgical Es- says (plate 2. fig. 6.), the head of the fe- mur had been driven by violence, applied laterally, through into the pelvic cavity, car- rying a comminuted portion of the aceta- bulum with it. The fracture was Y-shaped, and had radiated from the centre of the acetabulum pretty nearly in the line of the suture, — as we have before remarked in fractures here and in the ischio- pubic ramus. A fracture near or in the latter suture also existed. The limb presented the appearance of a dislocation of the femur backwards. In another case, the posterior part of the acetabulum was broken off, the fracture pass- ing across to the pubes, both innominate bones being broken and displaced, and the femur dislocated. The pubic symphysis was separated about an inch, the fibro-cartilage adhering to one bone only. The knee and foot were turned inwards, and the whole limb shortened two inches ; but it was more moveable than in a dislocation, and crepitus was felt on cautious extension being made. In a female whose pelvis had been crushed by a cart against a wall, a fracture was found passing through the body of the left pubis and the left ascending ischial ramus. Both the sacro-iliac joints had separated, part of the osseous sacral auricular surface of the right joint having come off with the ligaments. The pubes were separated at the symphysis. Motion and crepitus were felt on applying one hand to the ilium and the other to the pubis, and the posterior superior iliac spine projected upwards considerably. Through the vagina, the pubes were felt projecting into the vaginal cavity. There was much blood effused into the pelvis, and the patient died, sixteen days after, from sloughing of the soft parts. Otto mentions that, in the Museum of the Veterinary College at Copenhagen, are speci- mens of horses' pelves, fractured by excessive muscular action. Sir A, Cooper mentions three cases of fractured innominate bone which had reco- vered. Two were fractures of the ilium, easily detected by the mobility of the crista and crepitus. The third was a fracture of the ischio-pubic ramus about the suture. Rokitansky found that fractures of the pelvis rarely united without displacement. One of Mr. Barlow's successful cases of Cassarian operation was necessitated by the results of a fracture of the left innominate bone, which produced an elevation of the head of the thigh bone, shortening of the limb, and lame- ness. The contraction of the pelvic diameters resulted mainly from a projection backwards at the symphysis pubis, which was supposed to be caused by ossification of the disarti- culated joint, and which reached to within half-an-inch of the sacrum. Burns states that he has seen extensive pointed ossifica- tions projecting nearly 2 inches into the pekis, in consequence of fractured aceta- bulum. Naegele also mentions cases in which a bulging of the acetabulum inwards caused obstruction to parturition. Dr. Lever has also seen a bony process, more than an inch long, encroaching upon the pelvic cavity, in a male subject, after fractured acetabulum. Sometimes, after fractures of the pubis, the formation of callus has considerably inter- fered with the functions of the urethra. When ankylosis takes place at the sacro- iliac joint, after dislocation of the ilium back- wards, the pelvis assumes a shape closely re- sembling the pelvic oblique ovata of Naegele. A preparation of this kind is mentioned by Dr. Ramsbotham, as existing in the Museum of University College. BIBLIOGRAPHY. — Naegele, Das schrag verengte Becken (and' Appendix). Riyby, Midwifery (jn Tweedie's Pract. Medicine, vol. vi.). />. Robert Lee, Lectures on Parturition (in Lond. Med. Ga- zette, 1843.). Hull, Defence of the Ctesarian Sec- REPRODUCTION, VEGETABLE (VEGETABLE OVUM). tion (Letters to Simmonds). Barlow, Essays on Surgery and Medicine. Rokitansky, Pathological Anatomy (Hewett's Translation for Sydenham Society). Otto, Compendium of Pathological Ana- tomy "(Trans, by South). Pagct, Lectures oa Nutrition (in Med. Gazette, 1847). Meckel, Ma- nual of Descrip. and Pathological Anatomy. Lever, on Pelvic Tumours (in Guy's Hospital Reports, April, 1842). Velpeau, Traite' des Accouchements. E. Sandifort, De Ankylosi Ossium Pubis. Boyer, Traite' des Mai. Chir. Cooper, Sir A^ Surgical Essays ; in addition to the authors mentioned at the end of the article on the normal and comparative anatomy of the pelvis, and to the various cases cited in the text from the Medico-Chir. Transac- tions, the Edinburgh Journal, the Med. Observ. and Inquiries, and other periodicals. (John Wood.) REPRODUCTION, VEGETABLE. (VEGETABLE OVUM.) Before the mi- croscope was placed in the hands of the vegetable physiologist, the conditions by which he was surrounded in the investigation of the processes by which the embryo is formed, differed widely from those which exist at present. From the absence of means of observation, the phenomena of reproduction could only be studied in the Phanerogamia. Even as regards the highest cryptogamous plants, very little had been ascertained ; while the Algae and Fungi were involved in the most complete obscurity. But in the Phanerogamia it was already known that two kinds of organs were essential to the produc- tion of the embryo, and something had also been learnt of the mode of their combina- tion. No sooner were these facts established, than, with a readiness of which innumerable examples present themselves in the history of physiological investigations, they were at once seized upon to serve as the ground of a com- parison between the animal and vegetable kingdoms ; and naturalists soon passed to the conclusion that the organs in question were of distinct sexes, or, in other words, stood in the same relation to each other as those of animals. The analogy seemed sufficient for the mind to rest upon ; and the doctrine derived from it was received as indisputable. The influence exercised by the state of things we have just described, may be traced in two directions : — In the first place, a strong tendency is even now observable in the minds of naturalists, especially in this country, to ap- proach the subject from the same point of departure as before, when the circumstances were so different. The appearance of greater simplicity among the higher plants, was en- tirely dependent on conditions belonging ex- clusively to the observer; that is to say, on the imperfection of the means of observation. Now that so many of these imperfections are removed, to take the Phanerogamia as our starting point in approaching either this or any other general question in vegetable physi- ology, is evidently unreasonable ; we must commence our investigation where there are fewest complications — namely, at the unicel- lular plants. From this point we must ascend from class to class, following as closely as may 211 be the natural order of complexity of organisa- tion. A second result of the same causes is the confusion which so frequently arises in the employment of terms which are derived from the animal kingdom, such as " male," " female," " ovum," &c. As our knowledge of the sub- ject becomes more accurate, the grounds upon which the assumed correspondence between the reproductive organs of plants and animals rests appear less substantial. The only analogies, indeed, which can possess any real value are those occurring between the lowest members of the two series. This is the only point at which the two kingdoms are in mutual contact, and consequently it is here only that an actual correspondence can be traced through succes- sive consecutive modifications. The subject of the following article is the origin and development of the germ, or, in other words, the reproduction of plants by means of germs. Considering it as a conclusion, respecting which there can remain very little doubt in the present state of vegetable physiology, that every existing plant must have originated as a single cell, there are two modes in which this may be supposed to have taken place. In the one case, a cell originally forming a part of the tissue of the parent, and not previously dis- tinguished in any respect from its neighbours, suddenly assumes a new activity which it did not before possess. To this change the terra C4 Verjiingung," or, as it is rendered by Mr. Henfrey, " rejuvenescence," has been applied, and is most expressive of its nature. A cell in which there has previously been a gradual diminution in the intensity of vital manifesta- tions, recovers the capability of development which it possessed when first formed. Now, however, the formative force by virtue of which the whole subjects the development of all its parts to its own, being abated and weakened by age, the rejuvenescent cell be- comes individualised and is transformed into the rudiment of a new plant, in accordance with a capability of development, which resides entirely in itself. This process is called gem- mation. In the other case, the cell from which the new plant originates, manifests from the first moment of its existence conformity to law, on the one hand, in its anatomical relations to the organs of the parent upon which it is supported, or within which it is enclosed, on the other, in the mode in which its develop- ment commences — its transformation being the result of an activity inherent in it, not as an individual cell, but as being a part of the parent, and still under the control of its formative force. It is to this cell that the name germ is alone applicable in the restricted sense in which it is generally used ; namely, as expressing not only that it will, if it live long enough, transform itself into an embryo, but that it presents itself uniformly in the same species under the same anatomical condi- tions. The term " vegetable ovum," placed at the P 2 REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 212 head of this article, is employed in order to connect it with the preceding one on the " animal ovum," to which it is intended to form a sequel. In its usual acceptation in vegetable physiology, the word means the generative product of the Phanerogamia only. And even if we were to extend its meaning so far as to include all those varieties of germ, for the development of which two organs mutually dependent on each other for the ac- complishment of their reproductive functions are necessary, we should still he obliged to disregard one half of the vegetable kingdom. PART I. ALG^E, FUNGI, AND LICHENS. 1. Reproduction by means of Zcospores. — Among the most simply organised infusory animals are included several genera, which are admitted by all naturalists to present, in the aggregate of their characters, as many points of resemblance with plants as with animals. They agree with plants in their chemical con- stitution, in the mode in which they react on the atmosphere, and in their green colour. The Euglena viridis, which is so common in all our shady ponds, though in active motion during the greater part of its life, manifests at other periods a condition of plant-like repose. The contractility displayed in its rapid and ever-varying changes of form is a property which, there can be little doubt, manifests itself frequently among undoubted plants ; * so that the transition from the Eu- glenas to many of the forms of the Proto- coccus-like Algae is almost insensible. The elaborate researches of Cohn on the so-called Protococcus pluvialis, have unfolded many facts of the greatest importance in relation to this subject. The well-known permanent form of this plant is that of a globular cell, furnished with a distinct colourless membrane, and con- taining in its interior a semifluid protoplasma, in which numerous green or red granules are embedded. Cohn found that when water is added to Protococci in this condition, they immediately become the subjects of an active reproductive process. In the interior of each cell are formed, by the division of its contents, secondary cell-like bodies, the number of which is always either two, or a power of two. These bodies, which possess no distinct mem- brane, either give rise to stationary cells similar to their parent, or, as is by far more frequently the case, especially when the number of newly produced individuals is large, they become * The presence of contractility of the substance in true plants is still doubted by "some physiologists. One of the most accessible proofs of its existence is to be found in the motions of the tapering growing extremities of some species of Oscillatoria. Here we have changes of form of the substance of the plant, rapidly succeeding each other, and developed inde- pendently of the action of any external stimulus. These motions may be observed with perfect facility and occur under the most simple conditions. pear-shaped, fusiform, or oval ; at the same time they are endowed with the power of Fig. 127. Cell, of Protococcus pluvialis, containing moving Zoospores, about 25 diam. (Cohn.) active motion, and are furnished with a pair of vibratile cilia, emanating from their anterior Fig. 128. Free Zoospores of the same. (Cohn.) extremities. In the course of their further development, these actively moving bodies, which we shall call Zoospores, become invested with a distinct membrane. This seems to be a preparatory step to the cessation of their movements ; for shortly afterwards they are observed to lose their vibratile cilia, and as- sume a form which corresponds more or less completely to that of the mother cell. In many cases, however, before this result is ac- complished, a second reproductive process commences in the still ciliated zoospore. A division of its protoplasmic contents, similar to the first, takes place, and a second genera- tion of zoospores is set free, each of which is capable, after exhibiting active motion for a longer or shorter period, of becoming a sphe- rical, motionless cell, in all respects similar to the original parent. Thus an individual Pro- tococcus in its stationary form, may reproduce itself either directly, or with the intervention of a second generation. In the former case, the germ may either become at once an indi- vidual similar to its parent, or may pass through a preparatory period, during which it is not only provided with motor organs, but manifests in the protoplasm of which it is formed, a property of contractility resembling that of animals. Facts similar to the above are described by Braun as occurring in another unicellular Alga (Ascidiumacuminatum). This species, which is found attached to stones or other objects, resembles the Protococcus plu- vialis in its general form. By the division of the protoplasma which lines its cell-wall, numerous zoospores take their origin. These are pear-shaped, and at the apex of each is observed a pair of vibratile cilia. 2. In the above-described plants we have examples of the occurrence of zoosporous reproduction under the most simple condi- REPRODUCTION, VEGETABLE (VEGETABLE OVUM). tions. In the history of their development we have an epitome of that of all the more simple Algae. In the family of Protococci the type may be said to be included to which all the green and olive-coloured Algae, with the exception, on the one hand, of the.Des- midese and their allies, on the other of the Fucaceae, may be referred. Among the Des- mideae, indeed, is placed one genus, that of Pediastrum, in which the zoosporous is the only form of reproduction which has been observed. Pediastrum consists of a disc of cells, which are usually eight in number, and contain a protoplasma, which possesses a generally diffused green colour. The first step in the reproductive process consists in the separation of the protoplasma into a green and a colourless portion. The former, after collecting- mto a central mass, becomes divided into numerous secondary masses, the number of which is always a power of two. From the latter is formed a transparent gelatine-like in- vestment which lines the parent cell. After the completion of these changes the original cell- wall is ruptured, and the whole contents escape in a mass. No sooner has this taken place than the corpuscles into which the green protoplasma has divided, commence an active motion in the interior of the gelatinous cell in which they are included, and in fact display in every respect the form and peculiarities of zoospores. They are not, however, as in every other example with which we are ac- quainted, destined to display their activity beyond the narrow limits within which they originate. In a short time their motions be- come languid, and finally cease, while they arrange themselves in a beautifully regular geometrical order which corresponds exactly to that of the cells that constitute the adult Pediastrum. The next change observed is the disappearance of the gelatinous membrane, and the investment of each of the zoospores with a distinct covering of its own. From this there results a disc-like body, which, in a short time, assumes all the characteristics of the original parent.* 3. Taking these simplest of unicellular plants as our point of departure, we pass to the consideration of the confervoid Algae, many of which, though they are but little elevated above the Protococci as regards their struc- tural elements, present a general appearance which at first sight recalls that of plants very much higher in the scale of organisation. Thus in Bryopsis and its allies, in which the tubular frond branches in the most compli- cated manner, the whole consists essentially but of a single cell, the cavity of which is continuous throughout. When the formation of zoospores is about to take place, all that is observed in a Bryopsis is the accumulation of the green granular protoplasma towards the * The development of Pediastrum has been de- scribed by Braun (Die Verjungung in der Natur) as well as by Caspary (Botanische Zeitung, 1850, S. 786.). The description in the text is after Braun, with whom Caspary agrees in every important par- ticular. 213 extremities of the tubular branches. In these situations the cavity of the tube becomes completely filled, while at some point in the neighbourhood of each accumulation, the tube membrane becomes sacculated so as to present a nipple-shaped projection. In the meantime the accumulated protoplasma is observed to have given rise, by its division, to numerous green bodies, the forms of which cannot yet be distinguished, owing to the closeness with which they are packed together. No sooner, however, is this process complete, than a re- markable phenomenon, corresponding to that already described in Protococcus, manifests itself. The crowded zoospores, now com- pletely developed, at once commence their characteristic motions. From this results an appearance of confused agitation, to which the term " swarming " has been applied by the Germans. A minute aperture, or pore, is Fig. 129. a, termination of tubular frond of Bryopsis crowded with zoospores ; b, the same, after the escape of its contents. Each of these exhibits the lateral pore ; c, fully formed zoospores in active motion, a and 6 150 diam, c 200 diain. then found at the extremity of the nipple-like projection, apparently in consequence of the absorption of the cell-membrane at its apex. The zoospores now begin to escape, at first one by one, afterwards more rapidly, until at last a few only are left occupying the cavity of the tube.* 4. In the simplest forms of jointed con fer- vokls, the frond consists of a series of cells super- posed one upon the other, each of which is capable of producing zoospores independently of the rest. In the vegetative state, each contains only a green protoplasma. The re- productive process is the same in every respect as in the Bryopsideae, the opening by which the zoospores make their exit, being situated at the upper part of the cell, imme- diately below the septum, which divides it from its successor. In other cases (as in Mi- crospora), the zoospores escape by a kind of * Thuret, Recherches sur les Zoospores des Al- gues. Ann. des Sc. Nat. xiv. 217. p 3 REPRODUCTION, VEGETABLE (VEGETABLE OVUM). dislocation of the tube, each cell dividing into two in a plane parallel to the septa.* 5. The Ulvaceae, among which the frond has no longer the form of a filament, but assumes that of a membranous expansion of juxtaposed cells, still present the same phenomena to our notice. In the cells set apart for the forma- tion of zoospores, the green protoplasma is increased in quantity, at the same time that it becomes accumulated towards one point of the cell-wall. As the zoospores are formed, they are observed to converge with their apices towards this point. The phenomena attending their escape from the parent cell are similar to those which we have already noticed. 6. In some genera, which seem to be closely related in form and structure to the Bryop- sideae, we observe this important difference, that the zoospores are developed in an organ specially destined to this purpose, which presents peculiarities of form distinguishing it from every other part of the branching tubular frond. Thus in the genus Derbesia distinct spore cases are to be observed, the cavity of which does not communicate with that of the frond. These organs, which are of an oval form, take their origin in the same manner as the ordinary vegetative branches of which they are modifications. A young branch which is destined to become a spore case, instead of elongating indefinitely, begins, after having arrived at a certain length, to swell out into an ovoid vesicle, in the cavity of which a rapid accumulation of protoplasma takes place. The next change which oc- curs is the separation of this protoplasma from that of the rest of the plant with which it was before continuous, so as to give rise to an oval and opaque mass, which soon becomes surrounded by a distinct membrane. As the result of the division of this mass, a number of pyriform zoospores, each of which is fur- nished with a crown of cilia, are set free. Many other genera have been described by Derbes and Solier-|-, in which the relations of the spore cases to the frond are similar to those which exist in Derbesia, although the forms presented by the organs in question are infinitely various. 7. The researches of the authors above alluded to, along with those of M. Thuret, have shown us that in many families of the olive- coloured Algae, the occurrence of zoosporous reproduction is no less general. The zo- ospores, however, although they resemble in their general form those of the plants which we have been considering, differ from them not only in respect of their olive colour, but * In the genus (Edogonium, the protoplasma of each joint, instead of being converted into a number of zoospores, goes to form but one, which differs from those of other genera, in the first place in being considerably larger, and secondly, in present- ing around its rostrum not two, but a number of cilia, which are arranged in the form of a crown. (See Thuret, /. c. p. 226.) t Derbes and Solier, Sur les Organes reproducteurs des Algues. Ann. des Sc. Nat. xiv. 260. in the arrangement of their cilia. These organs, which are always two in number, are Sporangium of Ectocarpus siliquosus, 240 diam. Ectocarpus is one of the simplest forms of olive- coloured Algae, consisting of branching, conferva- like filaments. The extremity of any of the branches is capable of being converted into a sporangium by the absorption of the septa of the terminal cells. The zoospores are arranged in regular horizontal layers, the positions of which are indicated in the empty sporangium by faint markings of its membrane. usually of unequal length, and emanate not from the beak, but from the reddish-coloured point in its neighbourhood. The longest is directed forwards, being closely applied to the colourless beak ; while the other, which seems during the motions of the spore to serve as a rudder, assumes an opposite direction. In many genera a peculiarity exists, the significa- tion of which is not yet completely under- stood— that, namely, of a double fructification. The ovoidal sporangia (oosporangiay Thur.), which have been frequently described as single spores, in reality contain numerous zoospores. The other form (tricko-sporangium, Thur.) con- sists of a series of small cells joined together so as to form a narrow and generally short fila- ment. Each of the cells contains a zoospore, which, according to the observations of Thuret, is no less capable of germinating than the one produced by the oosporangium. In the genus Cutleria there is observed, for the first time, another feature of great interest and importance ; namely, the appearance of two kinds of organs which seem to be opposed to each other as regards their reproductive func- tions. The sporangia (trichosporangia) of Cutleria, not only differ from those of other genera, in respect of their greater size, but REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 215 present well-marked distinctive peculiarities the resulting cavities, zoospores are to be of structure. The frond consists of olive- found, which, though they altogether resemble coloured, irregularly divided Jlabelli, on each in structure those of the other olive-coloured Algae, are about three times as large. The Fig. 131. supposed antheridia of Cutleria communicate ^..J*S£T§ to the tufts of which they form a part, their x^ characteristic orange colour. The organs themselves are elongated, sausage-shaped ^^ vesicles: they contain a greyish, granular matter, in which, as the organ becomes ripe, indications may be observed of a division into several concentric layers ; the more internal of these layers being distinguished from those next the surface by the greater intensity of the orange colour which they present. After Fig. 133. a, a poi^ion of one of the tufts, or sori, of Cutleria, showing the mode of attachment of the filaments which support the sporangia to the surface of the frond; s, a ripe sporangium. Two others, half ripe, are also seen. Each is divided into eight compartments, in each of which is formed a zoospore, — 200 diam. ; b, zoospores ; c, the same in various stages of germination ; the earliest stage to the right, 300 diam. side of which, tufts (son), consisting of the reproductive organs, intermixed with hair- like bodies, are scattered at irregular intervals. The sporangia, and so-called antheridia, are borne by different individuals, but their po- sitions and arrangements on the frond are identical. The former consist of oblong or club-shaped bodies, which are supported by hyaline pedicles, set into their inferior extre- mities. The cavity of each sporangium is divided by three transverse partitions into four cavities, each of which is again bisected by a longitudinal median septum. In each of Fig. 132. Contents of anthtridium of the same, 400 diam. Each antherozoid is an oval hyaline corpuscle, which moves in the direction of its long axis. It exhibits towards its posterior extremity a coloured granule, from which springs a pair of cilia of unequal length. The longer of the two, which oscillates rapidly, is directed forwards ; the shorter, which is motionless, backwards. the discharge of the contents of the antheri- dium, it may be observed to consist of a transparent vesicle, which, like the analogous female organ, is divided by transverse and longitudinal septa into eight communicating cavities. 8. With the organs last described we think we need have little hesitation in comparing the structures to which the same name has been applied, as they occur in the Fucaceae. The fructification of these plants is, as is well Fig. 134. Portion of one of the sori of the male plant of the same. The ripe sausage- shaped vesicles, which contain antherozoids, are shaded. Others are shown which have already discharged their contents, 180 diam. The transverse markings, much too distinct in the engraving, indicate a tendency to the formation of compartments similar to those which present themselves in the sporangia. a, antheridia from the conceptacle of Halidiys sili- quosa, with the filaments on which they are sup- ported, 200 diam. ; b, antherozoids, 400 diam. known, enclosed in spherical cavities, situate under the epidermis of the frond, which are called conceptacles, and may be male, female, p 4 REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 216 or hermaphrodite, according to the organs which they contain. The male concepta- cles present in their interior an arrangement of branched filaments, or hair-like organs, which, taking their origin from the surrounding cellular tissue, converge towards the pore. At the summits of these filaments, the so- called antheridia are supported, which consist of little ovoid transparent vesicles. They contain, in their early condition, a granular protoplasmic material, but as they approach maturity, the so-called antherozoids make their appearance. These last are hyaline corpuscles, not exceeding about &0*00 of an inch in their longest dimension. Each con- tains a granule of a greyish or reddish orange colour, from which the organs of locomotion emanate. The form of the zoids differs ac- cording to the genus. InFucus, they are bottle- shaped, and each possesses a pair of cilia, one of which, the shortest, is directed forwards from the neck, while the longest emanates from the coloured point and is pointed back- wards. In Halidrys, the zoid is ovoid or spherical, and the longest cilium is directed forwards. In Fucus and several other genera, the transparent vesicle in which the zoids are immediately contained, is itself enclosed in a second of similar form. At the period of maturity this last gives way at its apex : the internal sack is expelled, and at once finds its way towards the external opening. In the meantime its delicate membrane disap- pears, and the liberated zoids commence their active motions. 9. Although the antherozoids of the Fu- coideae differ from the zoospores of the other olive-coloured Alga?, in their not possessing the power of germination, there are yet remarkable points of correspondence between them, in their form, structure, and mode of develop- ment. Both are composed of a hyaline pro- toplasma, and the position of the coloured granule, as well as the arrangement of the cilia, corresponds. They differ, in the first place, in size, and secondly, in respect of the chloro- phylle granules, which are present in the zo- ospore, but absent in the antherozoid. As regards the question of their functional sig- nification, they may be considered, on the one hand, as the elements of a male secretion, and the organs in which they are contained, as antheridia ; on the other, we may look upon them as the formal representatives of structures destined in other families to the performance of functions of which they are themselves incapable. In favour of the first of these views we have no direct evi- dence, and must trust entirely to analogy. We know that in Cutleria and its allies, the zoospores display the power of germi- nating without the slightest reference to the presence or absence of the secretion of the supposed male organ. Further, if, as all obser- vations which have been hitherto made, tend to prove, the zoospores of all the green Algae, and of so many of the olive-coloured, normally germinate under the condition of the constant non-existence of such organs, it is difficult to see why an exception should be made in favour of those of other families in which they are present. As regards the Fucoideae, we have certainly no evidence whatever that the antheridia perform any function, either more or less important in the reproductive process. 10. In the family of Vaucheriaceae, the zoo- sporous reproduction is remarkably modified by the substitution of a single multiple zoospore, of large size, for a number of smaller ones. The frond of Vaucheria consists of a branched tube, and much resembles in general form, that of the Bryopsideae, from which the Vau- cheriae in their vegetative condition differ only in respect of the arrangement of the chloro- phylle. The commencement of the formation of zoospores is announced by the condensa- tion of the green protoplasma in the rounded terminations of the branches of the plant. This condensation is accompanied with an enlargement of the cylindrical filament, which soon appears club-shaped, and is completely occupied by a confused and opaque dark-green mass. Shortly afterwards a septum is formed, which limits the terminal portion of the tube. Within the separate cavity thus formed, the mass of protoplasma becomes further con- densed ; its margin being surrounded by a clear space which intervenes between its external sur- face and the tube membrane. This body, which possesses an oval form, is the future zoospore. No sooner is it completely developed than the membrane which encloses it gives way at the apex, and it begins to insinuate itself through the resulting narrow opening. Having com- pletely freed itself, it forthwith commences an active progressive motion, which is accom- panied by a circumvolution round its axis. The zoospore at this period possesses no dis- tinct or consistent investing membrane, as is evident from the fact, that if, during its escape, it divides accidentally into two — a circum- stance which not unfrequently happens, from the relative narrowness of the opening through which it has to pass — each part is complete in itself and capable of germination. Its whole surface is covered with vibratile cilia, which are apparently connected with an epithelium- like structure. In this arrangement there seems to be an indication of a tendency to a division into smaller particles, by the melting together of a number of which the whole may be conceived to be formed. Like all zo- ospores its period of active motion is short; it soon becomes stationary and begins to germi- nate.* The zoospores of Vaucheria seem to correspond closely with the motionless spores of the true Dictyotaceae (Dictyota, Padina, &c.), as well as with those of the Fucaceae. In the case of the latter, the accuracy with which their structure and germination have been studied, has enabled us to follow out the analogy more closely. In speaking of the an- * See Thuret, Ann. des Sc. Nat. 2e S. xix. 269 ; Vaucher, Hist, des Conferves d'Eau douce, p. 246 ; Karsten, Die Fortpflanzung der Conferva fontinalis, Bot. Zeit. 5 Stuck, 1852. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). theridia ($ 8.), we described the general form of the conceptacles. In the monoecious and dioecious Fuci, the female conceptacles are distinguished from the male by their olive colour. The spores are developed each in the interior of a perispore, which is borne on a pedicle emanating from the inner wall of the conceptacle. They make their escape by the rupture of the perispore at its apex. At the moment at which this takes place, the spore is perfectly simple, except that in one or two species the surface is covered with cilia, which seem to resemble those of Vaucheria. Soon afterwards, a remarkable series of changes occurs, consisting in the splitting of the en- dochrome into a number of masses — usually eight — each of which becomes isolated, and finally assumes the form of a smooth and spheroidal sporule, provided with an investing membrane. About twenty-four hours after the completion of this process, germination com- mences. It consists in the budding out of the membrane of each sporule, at some point of its surface, into a nipple-shaped projection, which in the following forty-eight hours, elon- gates into a cylindrical tube; shortly afterwards the whole body of the sporule is converted by repeated division into a mass of cells, in which condition it has been by many writers mis- taken for the original spore, and described as such. The Vaucheria? present the peculiarity of a double mode of reproduction. In the earlier periods of the growth of the plant, there occurs the successive formation of aggre- gate zoospores of large size at the termination of the branches, as above described. In the older fronds these are no longer observed, their place being taken by organs producing germs which are capable of retaining for a long period their power of development. 11. In that most remarkable plant the Sa- prolegnia ferox, which is structurally so closely related to Vaucheria, though separated from it by the absence of green colouring matter, we find a corresponding analogy in the history of the development. Its vegetative life is, in fact, divisible into two well-marked periods, each characterised by a special mode of germ- formation. During the first, the only one with which we have at present to do, swarms of zoospores which rapidly succeed each other, are formed at the closed terminations of the cylindrical filaments. The mode of their origin, agrees with that of the aggregate zoo- spore of Vaucheria. The protoplasma accumu- lates in the swollen extremity of the filament, and a septum is formed in exactly the same manner as in that plant ; while the mass of protoplasma is now observed to be limited by a distinct surface. At this point the resem- blance ceases ; the protoplasmic membrane divides, just as in the spore-cases of the zo- osporous Algae, into particles, which, as the period of maturity is approached, become more and more easily distinguishable from each other. These particles are the future zo- ospores. Soon they detach themselves from their connection with the membrane which encloses them, and with each other, and pre- 217 sent the globular or ovoidal form characteristic of their perfect condition. In the meantime the external tube membrane buds out at its apex, so as to form a conical projection; as the zoospores become ripe, a gentle oscillatory motion is seen in the upper part of the spore- case. This is accompanied with a compres- sion of its contents, in consequence of which its membrane gives way at its weakest point, — viz. the apex of the terminal conical projec- Fig. 135. Sporangium of Saprolegnia ferox, during the expul- sion of the zoospores, 200 diam. (All the figures, from 129 to 135 inclusive, are from Thuret) tion. In its most perfect condition, the zo- ospore of Saprolegnia consists of a pyriform, protoplasmic, membraneless corpuscle, which is furnished with a pair of cilia, emanating from its apex. It is remarkable for the short dura- tion of its motion, the cessation of which la immediately followed by germination.* * For the history of the second period of the vegetative life of Saprolegnia, see below, § 19. It is only under the most favourable conditions that the zoospores of Saprolegnia assume the form described in the text. Very frequently at the period of their escape, they are sp'heroidal corpuscles unen- dowed with the power of motion, if uot incapable of germination. In this case, according to Anton de Bary, the completion of their development takes place outside of the spore-case. He describes the accumulation of the escaped, but imperfectly formed, zoospores in rounded heaps (Kopfchen), which re- main for several hours in contact with the termina- tions of the tubes from which they have escaped, and finally become invested with a* cellulose-mem- brane. Within this membrane their development is completed ; and when they at last escape, they REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 218 12. In the process of the formation of zo- ospores in Saprolegnia, we have an inter mediate step between that of the zoosporous Algae on the one hand, and that of a class of plants which is usually placed among the Fungi on the other. I allude to the Fungi included in the class Cystosporeae of Leveille ; on the intimate structure of this, as well as of many other allied groups, there are as yet but few re- searches. \Ve have, however, enough in the beautiful monograph of Cohn, on Pilobolus, to enable us to discover that it is structurally more closely allied to the Algae than to the Fungi. We shall take Pilobolus as an illus- trative example. 13. Pilobolus has an ephemeral existence. The spore germinates about mid-day; the plant grows till evening, ripens during the night. In the morning the spore-case bursts, and the whole disappears, leaving scarcely a trace of its former existence. In correspondence with the future mode of life of the plant, the spore-cell displays in its germination, a tendency to development in two opposite directions, by the formation of two sacculations, the first, cylindrical — the root; the second, ellipsoidal — the stem. Shortly afterwards the young plant is seen to consist of two cells, of which the inferior is elongated and branched at its lower extremity — root-cell; while the superior is ellipsoid, and acuminated above. The former contains a quantity of pro- toplasma, which lines, as a distinct layer, the internal surface of its wall. The first change which is observed consists in the accumulation of this protoplasma towards the apex of the cell, at which point the membrane buds out, so as to form a bead-like head. Within the cavity of this organ — the future spore-case, further accumulation takes place, until it is entirely filled with a coloured granular material; while the rest of the cell, from which it is as yet undi- vided, contains only a clear fluid. The pro- cess is completed by the formation of a septum just as in Vaucheria, which takes place early in the morning. This is immediately followed by the " cleaving" of the protoplasma, and its division into numerous small cells, which are the future spores. As the plant reaches the termination of its existence, the cell on which the spore-case is supported, enlarges at its upper part from the increase of its fluid con- tents ; the septum is pushed upwards, and presses on the contents of the spore-case. At last in the course of the forenoon, the tension of the wall of the spore-case becomes so great that it gives way at its junction with the sup- are pear-shaped, and possessed of cilia. These ob- servations I have been altogether unable to confirm, and am inclined to believe that the escape of the zoospores in the spheroidal form is to be attributed to an arrest of development, as in all cases which I have observed, the total disappearance of the spores has supervened shortly afterwards. — Anton de Bary, Beit. z. Kentnisse der Achlya prolifera. Bot Zeit. 28 St. 1852. For further information on porting cell with such force, that it is thrown like a miniature bomb for several inches.* 14*. The Fungi which agree in their develop- ment with the species above described, are limited in number, and belong for the most part to the genera Pilobolus and Ascophora (Mucor). The formation of the spore differs entirely from the process of strangulation, which Schleiden considers as characteristic of the Fungi. On the other hand, the analogies between Pilobolus and Vaucheria are of the closest kind ; even the ephemeral periods observed in the development and ripening of the reproductive apparatus, being the same. The root-cell of Pilobolus the inferior of the three of which the whole plant is composed, is as permanent as the tubular frond of a Conferva. From it emanate tubular, unjointed root-like processes, from the upper surface of which spring out at intervals young spore- cases, in every respect similar to the first- formed plant. These creeping rootlets con- stitute the vegetative system of the plant, which, like that of the Fungi, is perennial. 15. Reproduction by conjugation. — From the number of the observations which, during the last few years, have been made on the sub- ject of the phenomena of conjugation, no less than from the .variety of the conditions under which they have presented themselves, we are bound to assign them an important place in a systematic description of the repro- ductive process. Decaisne included in his group Synsporeae all the Algae in which the phenomena in question were then known to present themselves — namely, the genus Zygnema and its allies, along with Closterium, which last, for the same reason, he separated from the Desmideae. The beautiful researches of Mr. Ralfs have taught us that all the genera of the Desmideae conjugate in the same manner as Closterium. More recently analo- gous phenomena have been observed in the Vaucheriaceae, and in that remarkable plant Saprolegnia ferox, which so closely resem- bles Vaucheria in every respect, except its green colour. We shall describe in succes- sion each of the examples which have been mentioned. 16. Among the Desmideae, conjugation has been more frequently observed and described, and was known to take place at an earlier period in Closterium, than in any other genus. The earliest description is that of Morren, which is to be found in the Bulletins of the Aca- demy of Brussels, for 1836, and is among the most accurate that we possess. The crescent- shaped cell forming the frond of Closterium is, as in the Desmideae, composed of two similar halves, to the plane of junction of which its long axis is perpendicular. It differs from other genera in the absence of a median constriction, the junction being only indicated by a faint line in the external mern- Achlya, see Unger, Linnaea, 1843, p. 129. ; NSgeli Zeit, f. wiss. Bot. B. i. H. 1, 2. Prin Acta Ac. L. C. 1851. Cohn, Die Entwickelungsgeschichte des Pilo- Pnngsheim, Nova bolus crystallinus. Nova Acta Ac. L. C. p. 496. 1851. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). brane.* When two fronds are about to con- jugate, they place themselves parallel and op- posite to each other, with their concave sur- faces facing. We next remark that the cell membrane partially gives way at the line above mentioned, the two halves of each Closterium separating slightly on the side opposite its fellow, but remaining in contact on the other side. The openings are soon observed to be occupied by cushion-like projections of the in- ternal membrane, which squeeze out between the valves. From the fact that the cavity of the internal membrane is double, or rather that each half of the Closterium possesses an independent primordial membrane, it follows that each of the projections above mentioned consists of two distinct sacculi. Soon the two double cushions come in contact ; they are at first perfectly colourless, but shortly afterwards become filled with green granular matter, and press so closely together as to be no longer distinguishable. It is next observed that from the junction of the four sacculi, two canals have resulted, each of which soon swells out in a hemispherical form, corresponding to Fig. 136. Conjugation of Closterium, The two fronds are connected by two delicate tubes* each of which contains a hemispherical germ- cell closely invested by its membrane. The two germ-cells, which are in opposition by their flat surfaces, appear as one. About 40 diarn. that of a mass of green granular matter which now occupies its cavity. This mass is soon in- vested by a delicate membrane, which, in the progress of development, thickens and pre- sents an uneven surface. The two bodies which thus take their origin are the germ cells. They soon become free from the struc- ture in which they were formed, and, according to Morren, display for about fifteen minutes after their escape an active motion. After this period, the motion ceases, and they attach themselves to a foreign body. Morren has observed their germination. The spherical germ lengthens first at one, then at the oppo- site extremity, so as to assume the charac- teristic crescentic form of the plant. Its green contents divide into two masses, each of which is invested by a separate primordial membrane, and occupies one of the future seg- ments of the frond. In a short time the young Closterium completely resembles the adult. It is worthy of remark, that in the abnormal cases in which only one germ results from * Morren, Ann. des Sc. Nat 1" Ser. p. 325. the conjugation of two individuals, only one of the halves of each empties itself, the other remaining unaltered.* In other families of Desmidese, the pro- cess of conjugation, although variously modi- fied as to its less important details, is essentially the same as that which occurs in Closteriura.-{- 17. In the Zygnemaceae, confervoid plants, which seem to have a close relation with the Desmideae, the phenomena of conjugation have been long known. The frond consists of a series of cylindrical cells, which lengthens indefinitely by repeated division of its ele- ments. Here, as in the Desmideae, it is the last-produced cells in the filament which take part in the process of conjugation. In Spirogyra the union of two cells belonging to opposite filaments takes place by the ex- pansion of one side of each, so as to form a papilla, or short tube with a rounded end. The ends of the two projections then come into contact, become slightly flattened as they are pressed against each other, and unite. The double wall formed by their union, dissolves, or is broken through, so that a free passage is es- tablished between the two cell cavities. Upon this, the whole of the chlorophylle previously arranged round the inside of each of the cells, becomes a confused mass, which soon forms itself either in the cavity of one of them, or in the connecting canal, into a globular or oval smooth spore, invested with a colourless cellulose membrane. Having arrived at this condition, it remains several months — from the autumn of one year to the spring of the following, — without undergoing any change of form. J During this period two new membranes are produced within the first by the secretion of cellulose on the surface of the primordial utri- cle. Of these two, the external is of consider- able thickness, and of a yellow colour. The internal, which may be considered as the proper membrane of the spore, is delicate and * According to Morren, the process above de- scribed is not the only one by which the reproduc- tion of Closterium takes place. In the green granular matter contained in a frond, there occur spherical corpuscles which, according to that observer, are capable of reproducing the parent plant. He has described and figured their germination, and it is worthy of remark that his figures of the earliest stages of Closteria thus developed, correspond closely with those of the earliest stages of the plant as ob- served by Air. Ralfs, who, however, assigns to them a different origin. (See British Desmidete, tab. xxvii. m.) t It is clear that if the formation of germs by conjugation were the only provision for the repro- duction of the species, in the Closteria and many other families of Desmideae, its total disappearance must result, inasmuch as the conjugation and con- sequent destruction of a pair of Closteria can only give rise to an equal or less number of new individuals. But the other mode of reproduction already alluded to as occurring in Closterium, and which has been so well described by Mr. Ralfs in the other Des- mideas, affords an effectual safeguard against their otherwise possible extinction. J Braun has observed the germination of the spores in a specimen of Spyrogyra setiformis which had been collected for eleven months. (Braun, 7. c. p. 144.) 220 REPRODUCTION, VEGETABLE (VEGETABLE OVUM). transparent. Germination consists in the growing out of this membrane at one end of the spore into a many-celled filament, which escapes through a lacerated opening in the ex- ternal membranes, and gradually assumes the character, and appearance of the parent plant. At the same time a tubular elongation of the same membrane of limited growth is formed in the opposite direction, which is the rudi- ment of a root.* 18. In a species of Palmelleae (Palmoglea macrococca) in which the whole individual consists of a single ovoid cell containing green granular matter, and usually multiplying itself by successive division, the phenomena of con- jugation present themselves in a somewhat different and very remarkable form. Here two cells, probably the result of a series of divisions, undergo a complete union, affecting not only their contents, but also their mem- branes. They coalesce as completely at their points of contact, as two contiguous drops of water, the result of their union being a cell which differs in no"respect from its predeces- sors, except in the greater thickness of its walls, and in the complete conversion of the chlorophylle of its contents into oily globules. Like the spore of the Zygnemaceae, it is des- tined to a long period of inactivity, after which, by the successive division of its con- tents, it gives rise to a new series of individuals, similar to those that preceded it. 1 9. We have still to consider the most remark- able condition under which conjugation takes place among the Algae. The evolution of the aggregate zoospore of Vaucheria has been already described. In the plant which results from its germination, Karsten has observed that along the course of those filaments which come in contact with the atmosphere are formed organs of a peculiar structure. They originate like the ordinary branches, as nipple- shaped buddings out of the cell-wall, which are distributed in pairs along the whole course of the older filaments. In every pair of organs, one elongates so as to form a closed Fig. 137. A. portion of the tubular frond of Conferva fontinalis, showing the arrangement of the sexual repro- ductive organs. About 30 diam. (Karsten.) tube, which curves round into a spiral form, like the leaves of a Pilularia, while its fellow soon ceases to grow in length, but swells out into a globular or oval form, about three times as wide as the other. At first both contain chlorophylle, which, in the tubular organ, is soon replaced by colourless globules. In the meantime its fellow, which resembles a dark- green-coloured globe, supported on a short pedicle, alters in form, its cell-wall extending into a nipple-shaped projection on the side next the tubular organ, with which it finally comes in contact. This condition lasts for some time, but it does not appear determined Fig. 138. A single group more highly magnified, about 200 diam- Two of the egg-shaped organs which contain the germs are represented; one of which is in con- tact, by its smaller end, with the tubular organ which occupies the centre. (Karsten.) with sufficient distinctness by Karsten's obser- vations, that an actual interchange of the * Vaucher, Conferves d'Eau douce, p. 46 ; Pring- sheim, Annals of Nat. Hist. June, 1853. (Trans, by Mr. Henfrey.) contents takes place. All that we learn as certain is, that after the completion of what he calls the act of fructification, a newly formed cell appears in the cavity of the globular organ, which shortly after separates from the mother plant. In this instance, as in those above described, conjugation is pre- ceded by the conversion of the green gra- nular contents of the conjugating cells into oil globules. The germ thus produced re- tains its power of development for several months, and gives rise to a new plant re- sembling its parent in structure.* 20. In Saprolegnia, which is morphologically so closely related to Vaucheria, and like it, in its earliest state of existence, produces zoospores, we obtain, by the germination of these zoospores, plants which produce repro- ductive organs of an entirely different cha- racter. These, when completely formed, consist of spheroidal cells, each supported on a cylindrical pedicle. Each contains in its interior a number of round spores (from five * Karsten, Die Fortpflanzung der Conferva fon- tinalis. (Bot. Zeit. 1852, 6 Stuck.) The process of which the details have been so well described in the above memoir, was known to Vaucher, and is mentioned by him in his " Histoire des Conferves d'Eau douce" (p. 17.). See also Naegeli (Vergl. Algensyst. p. 175.) ; Hassall (British Fresh- water Algae, vol. i. p. 175.) ; and Thuret (Annales des Sc. Nat. 2nd Ser. 1843), who gives a figure illus- are very much more numerous than the curved tubular organs, a fact for the explanation of which observations are as yet wanting. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). or six to forty), which differ from the zoo- spores, not only in their external form, but in possessing a distinct investing membrane. This complication of structure corresponds with the capability of retaining their vitality for a long period. They may be found in an unaltered condition in the water in which the parent plant has grown for many ^months after the total destruction of the latter ; and it is to them, doubtless, that we must attri- bute the extraordinary facility with which the Saprolegnia makes its appearance whenever the peculiar conditions it requires present themselves.* On the filaments which produce the above-described spore-cases, there are developed among them, and at the same time with them, slender, worm-like branchlets. These, as they reach the spore-cases, attach themselves firmly to them, and even some- times wind round them in a regular manner. An actual interchange of contents, however, has not yet been observed.-j- 21. Re2^roductwe organs of the red Algce or FloridecE. — In this group of plants we unfortu- nately know too little of the origin and deve- lopment of the germ-producing organs, to compare them with the forms which prevail in other groups. It is altogether beyond the limits of the present article to describe in detail all the perplexing varieties of structures to be found in the Florideae which may be supposed to have some relation with the re- productive function. It will be sufficient to mention the three leading forms that are met with, and which may at all times be easily identified, in spite of the innumerable subor- dinate modifications that they undergo. The first form, to , which the term polyspore is usually applied, is that of a gelatinous or membranous pericarp or conceptacle, in which an indefinite number of sporidia are contained. This organ may be placed either at the summit or in the axil of a branch, or it may be con- cealed in or below the cortical layer of the stem. In other cases a number of sporidium- bearing filaments emanate from a kind of placenta at the base of a spheroidal, cellular pcrisporttngiumt by the rupture of which the sporidia which are formed from the entlo- chromes of the filaments, make their escape. Other forms, which it does not seem neces- sary to mention, are observed : they all agree in one particular, viz. that the sporidium is developed in the interior of a cell, the wall of which forms its perispore, and the internal protoplasmic membrane (endochrome), the sporidium itself, for the escape of which the perispore ruptures at its apex. 22. The second form is much more simply, and consists of a globular or ovoidal cell, con- taining in its interior a central granular mass, * Pringsheim, /. c. N. A. A. L. C. 1851. p. 417. All that is required to obtain a living specimen of this singular plant, is to allow the body of any small animal, such as a fly or spider, to float for a few clays in rain water, exposed to the light. By this method a crop of Saprolegnia may be obtained at any season. f Biaun. L c. p. 318. 221 which, as the organ arrives at maturity, divides into four smaller quadrant-shaped spores, which finally escape by the rupture of the cell- wall. This organ is called a tetraspore; it takes its origin in the cortical layer. The tetraspores are arranged either in an isolated manner along the branches, or in numbers to- gether, surrounded by a whorl of smaller branchlets. In some cases the form of the branches which contain tetraspores is so com- pletely modified by their presence, that they assume the appearance of special organs, which are called stichidia, as, for example, in Dasya.* 23. It is with respect to the third kind of reproductive organ, the antheridium, that the greatest differences of opinion exist; all observ- ers, however, agreeing as to the general sig- nification to be attached to it. The antheridia are always produced on different individuals, but in precisely the same situations as the tetraspores and polyspores. They are " ag- glomerations of little colourless cells either united in a bunch, as in Griffi thsia, or enclosed in a transparent cylinder, as in Polysiphonia, or covering a kind of expanded disc of peculiar form, as in Laurencia." -j- According to the researches of Derbes £ and Nageli §, each of these cellules contains a spermatozoid. Nageli describes it as a spiral fibre, which, as it escapes, lengthens itself in the form of a screw. Derbes, on the other hand, describes it as "a hyaline globule, furnished with a flagelliform appendage, by means of which it agitates itself with a very active motion, which lasts for some moments." According to M. Thuret, who certainly is to be considered a higher authority than either of the above men- tioned, each cell of the aniheridium is occupied by a hyaline corpuscle, spherical in Polysi- phonia, ovoidal in other genera. These cor- puscles, however, whose contents are granular, offer no trace of a spiral filament, but are ex- pelled from the cells by a slow motion, which Thuret compares to that observed in the ex- pulsion of the tetraspores from their theca. The antheridia appear in their most simple form in Calithamnion, being reduced to a mass of cells, composed of numerous little bunches, which are sessile on the bifurcations of the terminal branches. The woodcut represents the antheridium of Griffithsia, in which species, it is produced like the tetraspores, in a sort of lateral involucre of verticillate branchlets. Each of these bifurcates, and bears at the bifurcation a pyramidal antheridium, which * See H. H. Harvey, Nereis Boreali Americana, Part ii. passim. New York, 1852. The best descriptions of the organography of the Florideae will be found in the Essay of Decaisne on the Clas- sification of the Algae in the Ann. des Sc. Nat. 1842 ; and in Nageli's Zeitschrift, f. w. Bot. Heft. 3 & 4. Zurich, 1846. f Thuret, Ann. des Sciences Nat. 3me Ser. xvi. j Derbes, Ann. des Sciences Nat. 3me Ser. xiv. 261. ; These de Botanique, p. 25. Paris, 1848. 8 Nageli, /. c H. 3 & 4. S. 224. Zwei Bemer- kungen, &c. Bot. Zeit. 1850. 32 StUck. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 222 is composed of little bunches of hyaline cells, which are arranged round a central axis, 139. Antheridia of Griffithsia, 30 diam. a, a kind of involucre is formed by a whorl of six verticillate branchlats, at the points of bifurcation of each of which is borne an antheridium ; 6, terminal tuft from surface of antheridium, along with a few of the hyaline vesicles, 300 diam. (Thuret). formed of larger cells placed end to end. At the junctions of these, smaller branches are given out, upon which the hyaline cells are sessile. These last possess a diameter of about yJ^ of an inch. From the above details it will be seen that great difficulties lie in the way of a comparison between the reproductive organs of the Flo- rideaa and those of other families. Nageli considers them to present a strong analogy with those of the Hepaticae, with which he places the Florideae in a parallel position. We shall see, as we advance, how little ground there is for such a view. The Florideae are trioecious plants : the tetraspores, polyspores, and antheridia being never found together in one individual. 24. CharacecB. — Although we are well ac- quainted with the structure of the reproductive organs of the Characese, we are, as yet, able to perceive only subordinate relations between them and those of other plants. These organs are of two kinds ; the one being destined to the production of a germ, the other to that of antherozoids. The former is an oblong oval body, which is placed at the junction of two segments of the articulate tubular stem. It consists of an oval germ-cell, invested by two envelopes. The outer of these is remarkable for the arrangement of the five tubular cells of which it is formed, which are twisted spirally round the central parts, and form by their ends, at the summit, a crown of five teeth. The germination of Chara has been ob- served and described by Vaucher.* The de- velopment of the germ, which ripens in autumn, does not take place until spring. It * Vaucher, Me'm. Soc. Hist. Nat. de Geneve, torn. i. consists in the budding out of the central cell at its apex so as to form a single tubular stalk, just as in the lower Algae. 25. The antheridium of Chara is an orange- red, and globular body, which is attached to the stem immediately below the germ-producing organ. It consists of eight concave, rectan- gular valves, joined at their edges so as to form a hollow sphere. At each suture there is a partition, which is directed to the centre of the sphere ; while from the centre of each valve there springs a cylindrical cell, the axis of which is perpendicular to its inner surface, so that each cell approaches the centre of the sphere by its extremity. The whole anthe- ridium is supported by a ninth cylindrical cell, which is inserted by its base into the stem of the plant, and passing up between the corners of the four inferior valves, approaches the other eight cylindrical cells at the centre. From the extremities of the nine cells, there emanate a number of flexible tubes, which are Fig. 140. a, flexible tubes from antheridium of Chara. From most of the segments the antherozoids have escaped ; two are in the act of escaping : b, fully formed antherozoids. 400 diam. (Thuret.) divided by transverse partitions into a number of segments. In each segment or cavity an antherozoid is contained. Each antherozoid is a spirally coiled fibre endowed with a power of active motion, which is displayed as soon as it is removed from its cell. The motion is of two kinds — of progression, and of revolution round the axis. According to Thuret, two cilia emanate from each antherozoid, a little behind its anterior extremity, and it is to these organs that the motion is to be attri- buted.* 26. Summary. — If we take into consideration only those families of the Algae in which the phenomena of reproduction have been more or less completely investigated, we shall find that all the instances of the occurrence of bodies to * For further information see K. Miiller, Die Entwick. der Characeen, Bot. Zeit. 1845, p. 393. Kaulfuss, Die Keimung der Characeen. Leipzig, 1825. Varley, On the Structure of Chara in the Microscropic Journal. Thuret, Ann. des Sc. Nat. xvi. p. 18. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). which the term " germ" may be applied in the sense of the definition given at the outset, may be included in one of two classes. The first comprises zoospores and zoosporoid bodies ; the second, all those forms of germ which re- quire for their development a previous combi- nation of two parts or organs, complementary to each other as regards their reproductive functions. 27. Zoospores. — Of zoospores we recognise two kinds, simple and aggregate. The simple zoospore is a pear-shaped or ovoidalbody: it is composed of transparent, colourless homo- geneous plasma, throughout the whole of which, with the exception of the smaller end (rostrum), granules of colouring matter are scattered. It possesses no investing mem- brane, but is provided with a pair of cilia, the directions and positions of which differ accord- ing to the class. Every zoospore possesses a single granule of a red or reddish-brown colour, which is always placed in the immediate neighbourhood of the colourless rostrum. Its characteristic motion is a constant progression in the direction of its axis, around which the whole zoospore at the same time revolves, the transparent rostrum being always directed forwards. As regards the chemical composition of the zoospore, the transparent and colourless plasma is a nitrogenous compound, coloured brown by iodine. The cilia, as far as their reactions can be ascertained, resemble the plasma from which they emanate. As to the constitution of the coloured granules which are scattered throughout the plasma, we have as yet no direct observations ; but from the form which they exhibit being that which is always assumed by starch, not only among the Algae, but also in the green Infusoria, there can be little doubt that they are composed of that principle, in mechanical combination with colouring matter and a fat. 28. In passing from the condition of motion to that of repose, or, in other words, in germi- nating, the zoospore is not subject to any sus- pension of its vegetative activity. From the moment that it is set free from the parent plant to that at which it begins to develope from itself a new plant similar to the parent, it continues to grow uninterruptedly. 29. Of the aggregate zoospore, the best- marked example is that which has been fully described in Vaucheria. In comparing the termination of a fructiferous filament of Vau- cheria, with the sporangium of Saprolegnia, we can at once satisfy ourselves that these are corresponding structures ; the distinctive dif- ference being, that in the one the whole pro- toplasma contained in the termination of the tube is collected together to form a single large zoospore, while, in the other, it is subdivided so as to form a multitude of small ones. In other words, the single zoospore of Vaucheria takes the place of the collection of zoospores con- tained in one sporangium of Saprolegnia. This fact is all that we mean to imply by the use of the term aggregate. 30. Zoosporoid bodies. — Among these we in- clude the antherozoids of Cutleria, of the Fu- 223 caceae, of the Florideae, and of the Characeae. Of the relations of the first two to the true zo- ospore in form and development, we have al- ready said enough in theprecedingpages. Those of the antherozoid of Charaare not so close; and the structure of the organs in which they are developed, differs so essentially from any structure met with in any other family, that it is inexpedient to found any notions of their nature or formal relations upon such slender analogies as may exist. In the case of the Florideae, the correspondence between the antherozoids and the zoospores of other Algae, is still less trace- able ; but the peculiar arrangement of the bodies in question — their being always deve- loped in different individuals, though in similar positions as regards the organs of vegetation— - leads us irresistibly to the conclusion that they have a mutual relation, or are in some degree complementary to each other in function; and as we know the production of germs to be the function of the one, it is reasonable to assign their fecundation to the other. GermSy whose development is dependent on the combination of two organs the reproductive functions of which are complementary each to each. — Of these it is the leading characteristic that they do not necessarily pass at once, as soon as they are set free from the parent, into active development. If the necessary condi- tions of temperature and moisture are absent, they are capable of remaining in a state of re- pose, without losing their power of germina- ting. This state may last for weeks, or even for months. Their second characteristic is connected with the first ; viz. that they are always provided with a distinct investing mem- brane, on the strength of which their power of resistance to external agents may in part de- pend. This is well seen in the spores of the Desmideae and Zygnemaceae. 31. There remain a few examples of germ- like bodies of uncertain signification, which are included in neither of the above divisions. Such are the various forms which occur among the Florideae, the stationary spores of Sapro- legnia, and others, of which, as they are still imperfectly known, sufficient has been said in the preceding pages. 32. FUNGI AND LICHENS. — While, on the one hand, the Fungi and Lichens present an endless variety in the organs which constitute their reproductive system (receptacle), their vege- tative system (mycelium, stroma, flocci, hypo- thallus, #c.), on the other, preserves a remark- able degree of uniformity. It always consists of a network of cylindrical hollow* filaments, usually divided at irregular intervals, but some- times simple. In the latter case the whole network, however complicated it may appear at first sight, is in fact only a ramified cell. This structure, which, in its simplest form is the immediate result of the germination of the spore, is the most permanent portion of the plant, inasmuch as, although every part of it, considered separately, is transitory, the vege- tation of the whole is continuous, and its duration unlimited. It is from it that the organs which constitute the reproductive sys- 224 REPRODUCTION, VEGETABLE (VEGETABLE OVUM). tern take their origin, and, as its presence is essential to the existence of the plant, it may be considered to represent, functionally, the stem of other vegetables. 33. On the formation and development of the germ in the Fungi, comparatively very few researches have yet been made which are not so deficient either in completeness or accuracy as to be useless. This being the case, the best mode of treating the subject seems to be to select those isolated facts and observations which are most to be depended upon, and arrange them in such a manner as to serve as a foundation for a general view of the subject. The most simply organised Fungi known, are undoubtedly those which belong to the genus Torula. The well-known yeast-plant consists of a single ovoid cell, whose membrane is per- fectly simple, and encloses a slightly granular, transparent fluid. It multiplies by the budding out of its membrane at one extremity into a projecting nipple, which soon becomes sepa- rated from the original cell by a constriction. As the newly formed germ enlarges, the con- striction becomes more complete, and at last separation takes place. After the Torulae, which are the only examples we are acquainted with of one-celled Fungi, come the innumerable Hyphomycetes or thread Fungi,so called because their reproductive, bears so small a proportion to their vegetative system, that it is in many cases altogether overlooked. The growing terminations of the mycelium filaments them- selves become individualised, so as to form the germs, which separate from their parent cells by constriction, as above described in Torula. It is this acrogenous mode of spore formation which Schleiden considers as the character which distinguishes the true Fungi from the Lichens*; the latter developing "many spores simultaneously in the interior of a larger parent cell or ascus." Among the higher Hyphomycetes, however, the reproductive sys- tem appears in a more distinct and developed form. Thus, in Penicillium it consists of fila- ments which spring perpendicularly from the stroma, and are formed of elongated, club- shaped cells, joined end to end. These stalk- like filaments branch trichotomously in the most beautiful manner. From their extremi- ties there spring others, which are much more slender, and consist of moniliform series of minute ovoid segments, separated from each other by constrictions, which are indistinct at the base of the filament, but become more and more complete towards its termination. At this point the segments detach themselves, and form the germs of the plant.-)- In other genera, the perpendicular sporiferous filaments are woven together into more complicated structures, the varieties of which it does not come within our present purpose to describe. As respects their component elements and the * Schleiden places all the ascophorous Fungi among the Lichens. V\re shall find, as we proceed, that such an arrangement is altogether inadmissible. (Schleiden, Principles of Scientific Botany, p. 157.) t Corda, Icones Fungorum, torn. i. p. 21. mode in which the spores are produced, they do not differ from those noticed above. Fig. 14-1. Branching sporiferous filaments of Penicillium verti- cillatum, about 150 diam. (Corda.) 34. The basidiosporous Fungi are character- ised by the presence of a distinct membrane (hymenium), on the surface of which the spores are developed by a mode which, though it is still acrogenous, is considerably more complicated. The hymenium always consists of elongated pouch -like cells, ar- ranged side by side, with their long axes perpendicular to its surface, and in close contact with each other. Some of these cells are longer than their neighbours, and from their free rounded ends, there emanate processes (usually four in number) in the form of pedicles. Upon the extremities of these are borne oval cellules, which, though in their Fig. 142. A. basidium with its four basidospores, along with tu-o other sterile basidia (Geaster rufescens),'3QQ diam. earliest condition they do not exceed their pedicles in width, rapidly enlarge, and finally separate by a kind of constriction. In some basidiosporous Fungi, as in the Agarics, the hymenium is external, and its surface exposed to the atmosphere ; while in others, as in the Gasteromycetes, it is internal, the spores being thrown, when detached from their pedi- cles, into one or more cavities enclosed in the substance of the receptacle. Of the last- mentioned division, we select a well-known genus (Geaster), for the purpose of illustration. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 35. At the period of the formation of the spores, the receptacle of Geaster (fimbriatus) is a solid body of a depressed spheroidal form. It presents for examination a central mass and a peridium, the tissue of the latter being con- tinuous with that of the former only at the base. The central mass or kernel is originally Fig. H3. Diagram of receptacle of Geaster fimbriatus. The kernel, a, is surrounded by its reticular mem- brane, which is indicated by the inner of the two double lines. The outer double line corresponds to the resistant external layer of the peridium. The intervening space, 6, is occupied by a delicate tissue of spherical cells. At c, all these struc- tures are continuous, as well with each other as with the mycelium from which the whole ori- ginates. solid, but when fully developed, presents numerous irregular cavities, which are scat- tered through its substance. It is entirely composed, when in the solid condition, of delicate filaments similar to those of mycelium, the arrangement of which is as follows : — The superficial filaments are closely woven toge- ther, so as to form a delicate reticular mem- brane, which invests the whole kernel, and from the inner aspect of which a second and very numerous, set of filaments passes off towards the centre. It is of these, or of their ramifications, that the corky, semi-elastic sub- stance of the kernel is entirely formed. If we examine the cavities which have been men- tioned as existing in the fully developed con- dition, we find that they are furnished with a Section of a portion of the young receptacle of Geaster rufescens, about 100 diam. The section has passed through one of the cavi- ties, and shows the arrangement of the basidia which form its lining membrane. Some of these bear spores on their summits. more or less continuous lining of basidia, bear- ing spores on their summits. These basidia have been shown, by careful observation, to Swpp. 225 be in fact the swollen terminations of the centripetal branching filaments above men- tioned. The peridium it is less necessary to describe, as it has no immediate connection with the spore-bearing organs. It consists of an internal and an external layer, the latter being smooth and very resistant, while the former consists of delicate, transitory, spheri- cal cells. In the ripe condition of the Geaster, the peridium becomes detached, at the same time splitting from apex to base in a remark- able and characteristic manner. Geaster may be considered as the type of a well-known family, including the Ly coper dons, Bovistce, and others, all of which are characterised by the presence of a solid receptacle, furnished with numerous spore-bearing lacunae. In al- most all of these Fungi, the arrangement of the spores with their pedicles in relation to the basidia are the same, four pedicles ema- nating from each basidium. In the ripe con- dition the spores are always of a dark-brown colour, frequently approaching to black, and their surfaces are beautifully reticulated with linear furrows, between which there are little conical projections. Each spore possesses an external reticulated, and an internal homo- geneous membrane. This last encloses a cavity, which is occupied by a fluid, which contains numerous oleaginous granules. The ripe spores, after their detachment from the basidia, lie loose in the lacunas of the recep- tacle from which they are set free by the dis- integration of the basidia, as well as of the filament with which they are connected. In this manner, in Geaster, the kernel is con- verted into a bag, formed of the delicate reti- cular membrane, described above as its proper investment. This bag contains a dark-brown diffluent mass, composed of the remains of the basidia and filaments along with ripe spores. Finally, the membrane gives way, and the spores are disseminated in the shape of a light, dry-looking powder. 36. We next pass to the consideration of the Fungi, among which the spore, instead of being produced at the summit of a basidium, or at the extremity of a simple filament, is formed in the interior of a vesicle or pouch, which is called a theca or ascus. Of these, the first which we shall mention belong to a group of subterranean plants, of which the truffle is the best-known example. The recep- tacle of the truffle consists of a fleshy mass, throughout which numerous sinuous cavities are interspersed. Each cavity is partly lined, partly filled with the thecae and the cells upon which they are supported. This receptacle, like that of all other Fungi with which we are acquainted, originates from a pre-existing mycelium. In its unripe condition it displays on section a number of sinuous empty cavities, which either communicate with each other, or open at one or more points of the external surface. As the truffle advances towards maturity, the cavities are obliterated by the formation of a whitish tissue ; so that on sec- tion, we observe the whole to consist of two substances — the one translucent, of firm con- Q REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 226 sistence and of a dark-brown colour ; the other white and opaque. The former, which cor- Fig. 145. Sectfon o/par< o/ fAe receptacle of a Truffle, about 250 a, outer layer of the peridium consisting of a resistant tissue of thick- walled cells ; b, inner layer of the same, formed of filamentous tissue continu- ous with that of v, one of the venae internae, or par- titions by which the compartments (originally cavities) of the truffle are bounded. Portions of two of these compartments are seen with the thecae and septate filaments which they contain. responds to the partitions which, in the young state of the truffle, separated the cavities, is continuous with the external tissue which composes the envelope or peridium, and con- stitutes the vena interne of Vittadini.* The laminae which it forms, consist of filaments running, for the most part, parallel to each other. The white substance which occupies the original cavities of the tuber, is formed of closed tubes, which are given off in great numbers from the surfaces of the laminae. These tubes, which are the terminations of the filaments of which the laminae are com- posed, are of two kinds. Some are of equal diameter throughout, and divided at intervals by septa ; others, much shorter, are dilated at their extremities, and contain spores (thecae). Each theca is an obovate vesicle, and con* tains two, three, or more spores, never more than eight. Each spore is invested with a beau- tifully reticulate, or sometimes warty epispore, within which may be distinguished a smooth inner membrane, immediately enclosing the oleaginous contents.*}* * Vittadini, Monog. Tuberacearum, p. 2. et seq. f L. R. & C. Tulasne, Histoire des Champignons hypogees, 41-50. 37. The ascophorous Fungi are represented in their simplest form by the Uredineae, a family which has been studied by numerous observers on account of the destructive pro- perties of the plants belonging to it. The mass which is formed by the growth of the reproductive organs of Uredo under the epi- dermis of the leaves of the plants upon which it grows parasitically, may be aptly compared to a pustule, a grumous-looking substance, occupying, as it were, the place of the pus. On more minute examination of the cavity, we find that it is bounded by a kind of irre- gular wall or lining of pyriform cells, the smaller ends of which rest upon a reticular cushion of mycelium. These are probably the enlarged extremities of the mycelium filaments, with which many of them can be distinctly traced to be connected. Towards the base of the cavity other cells are developed, resem- bling those first mentioned in their general form, as well as in their relation to the myce- lium. In these, however, the membrane is produced inferiorly, so as to form a tubular pedicle ; while in the club-shaped upper ex- tremity it is lined by a considerable deposit of granular protoplasma, so that here the central cavity is very much smaller than that of the external membrane. It is in this cavity that the spore is formed, at first not exceeding it in size, but afterwards increasing at the ex- pense of the protoplasma, so as almost to fill the theca. In other genera, as in Phragmidium, there are pedicled cells of a similar form, and originating in a similar manner, which, how- ever, instead of one spore, develop a number in their interior ; these spores are arranged in linear series, and are formed in the same manner. The protoplasma, however, never disappears completely, but remains as a more or less consistent membrane, glueing the ripe spore to the spore-case which encloses it. Some of the Uredineae possess a cyst which re- minds us of the perithecium of the Sphoeriaceae, to which they are evidently closely related. The cyst is formed (QEcidium) of a single layer of roundish cells.* 38. From the Uredineas we pass by a natural transition to the Discomycetes and Pyreno- mycetes. These plants have been investi- gated with much success by MM. Tulasne, who have shown that they possess the closest relationship not only to the Lichens, but to the most simple thread Fungi. The very remarkable facts which these observers have discovered, render the study of these plants more satisfactory and instructive than that of any other family of the class. The Pyrenomycetes are represented by Sphoeria, the receptacle of which consists," as is well known, of a spherical cyst, which is open above. Its wall is frequently prolonged up- wards into a tubular beak, which projects beyond the surface of the bark or wood in which the whole plant is embedded. The membrane of the cyst (perithecium) is usually * }j. R. Tulasne, Recherches sur les Uredine'es, &c. Ann. des Sc. Nat. 3me. S. t. vii. p. 12. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). composed of polygonal, tabular cells ; it is lined by an inner layer, formed of the com- mencements of the paraphyses and thecae, and of the filaments with which they are con- nected. The thecae are obovate cells, the Fig. 146. Theca and paraphyses of Sphoeria, about 300 diam. membrane of which is of extreme delicacy. When fully formed, they contain from three to eight oval spores, the epispores of which are in the early condition delicate and pellucid, but by degrees become brown and opaque. Fi%. 147. Ripe spores of Cenangium Frangulae, 350 diam. The contents of the spores, as is observed throughout the higher Fungi, consist of a fluid loaded with oily granules. The thecae are arranged with their long axes perpendicular to the inner surface of the perithecium from which they spring, and are intermixed with a greater or less number of slender, cylindrical paraphyses. The whole perithecium is usually enveloped in the filamentous stroma or my- celium, from which it takes its origin. The Discomycetes are represented by thePezizae; between these and the Sphceriae there are dif- ferences of external form, which, though they strike the superficial observer as important, are in reality trivial. While the receptacle of the Sphoeria is a cyst with an apicial aperture, that of the Peziza is a cup-shaped disc, the concave surface of which looks upwards. This surface is lined with an ascophorous mem- brane, which resembles in every respect that of a Sphoeria. 39. Along with the Pezizae and Sphceriae and those allied genera which resemble them in producing their spores enclosed in thecae, there are other forms also included in the 227 Pyrenomycetes and Discomycetes, which, while they resemble those last named in th e general outline and structure of their recep- tacles, differ from them completely in the mode of origin of the spores. The simulta- neous occurrence of some of these forms, along with their ascophorous analogues, or, in other instances, the successive develop- ment of both kinds of receptacles in the same position, had been frequently observed, and had given rise in the minds of some my- cologists to the suspicion of the existence of a relation more close than was generally ad- mitted. This suspicion did not, however, take a sufficiently distinct form to lead to observation until the MM. Tulasne, in a series of researches scarcely completed, showed that the genera in question, hitherto con- sidered as distinct, were in fact identical, and that receptacles containing thecae and para- physes, are produced on the same stroma, or, in other words, on the same individual plant, as those which contain acrogenous spores. 40. The earliest researches of MM. Tulasne* were directed to the Pyrenomycetes. In some species of Sphceria, they found not only that the same stroma produces receptacles with acrogenous spores, which are followed by others bearing thecae; but that, under cer- tain circumstances, it may give rise to spore- bearing organs, of a much simpler character; viz. branching filamentous pedicles, bearing at their terminations single spores, and rising directly from the mycelium filaments, with which they are continuous. In this condition the plant cannot be distinguished from a thread Fungus, and has been hitherto described as such. 41. The later observations of MM. Tulasne f which are much more in detail, refer almost entirely to Discomycetes. In a species of Rhytisma, a genus of Discomycetes, which inhabits the epidermis of the leaves of plants, the stroma at first presents the appearance of a black spot of various extent on the surface of the leaf. In the substance of this stroma the first receptacles are formed ; they are cushion-shaped capsules, furnished with api- cial apertures, like those of Sphoeria, and are entirely occupied by a pulpy nucleus, which con- sists of slender branched filaments, often so long as to project considerably beyond the aperture. These filaments bear at their extremities innumerable minute linear sporules, which are enveloped in an abundant mucilage, and are expelled from the ripe capsules in the form of a long cirrhus. After the capsules which are developed during the early summer months have discharged their contents, they are succeeded by the lirelliform discs of the perfect Rhytisma. These do not arrive at maturity until the following spring, and bear * Notes sur 1'Appareil reproducteur dans lea Lichens et les Champignons, Ann. des Sc. Xat. 3me. S. t. xv. p. 370. f Nouvelles Recherches, &c. Coraptes rendus, Seance du 13 Dec. 1852. Q 2 REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 228 upon their upper surface thecae and paraphyses like those of a Peziza. In other genera MM. Tulasne found that the ascophorous receptacles are preceded by capsules which produce, instead of the linear sporules above mentioned, cylindrical spores of a much larger size, each of which is supported at the extremity of a pedicle of its own. 42. Thus in the plants under consideration we find that, without counting the sporules which are produced by filaments rising directly from the stroma, there are no less than three varieties of spore-like structures which can be easily distinguished from each other. All of these may be produced upon the same, individual, and one instance is recorded in which a cupule of a Peziza was found, which bore among the normal thecae, para- physes with innumerable, slender, linear sporules at their extremities. As has been already hinted, the capsules which contain acrogenous spores, have been hitherto con- sidered as belonging to genera distinct from those represented by the ascophorous recep- tacles with which they were found associated. The genus Cytispora is characterised by a structure which corresponds completely with that of the capsules described above in Rhytisma ; and other genera as e. g. Sporocadus have a similar relation to the capsules, containing the larger variety of pedunculated, cylindrical spores. 43. In order to facilitate the description of these various structures, a nomenclature has been devised by MM. Tulasne, which may be adopted with advantage. The minute, linear sporules, which are produced at the extremities of branched filaments, like the paraphyses of Sphaeria, are called spermatia. The cylindrical bodies of much larger size, which are borne each at the extremity of a stipitiform cell, are named stylospores ; while the term spope is reserved to those which are formed in the interior of a theca. 43. big. In a third " Memoire " which has appeared since the above paragraphs went to press, MM. Tulasne have further prosecuted their researches on this interesting subject. The following is an abstract of their account of the development of a Pyrenomyces (Ce- nangium), which inhabits the bark of dead branches of the black alder (Rhamnus Fran- gula). The plant, in its natural position, is represented inj^g. 148. The mycelium ramifies, in all directions, in the substance of the inner bark of the dead branch. From its filaments there spring, at irregular intervals, the re- ceptacles, which as they develope, burst through the outer bark and epidermis and exhibit the various forms represented. The simplest variety( fig. 148. a) resembles in struc- ture the organ described in § 49. as occurring in Scutula. In form, it is rounded, but at the same time somewhat conical. The stylo- spores (Jig. 149. a) which it contains, are Fig. 149. a, group of stylospores, with a fragment of the wall of the receptacle in which they are enclosed; b, similar group of spermatia. About 300 diarn. curved, crescentic bodies, supported on pedi- cles, which have an arrangement perfectly similar to that observed in Scutula. The receptacles or cupules in which thecae are produced are deserving of great attention. In the early condition, their form is cyathoid (fig. 148. c), and they resemble those de- scribed (§41.) in Rhytisma. They contain at this time, innumerable spermatia (fg. 149. 6), these being supported on filaments which spring from the inner surface of the cup, as well as of its margin. As the organ grows, it expands, and finally becomes discoid (fig. 148. b}, when it possesses the structure Fig. 150. Fig. 148. Part of a dead branch of Rhamnus Frangula, with Vertical section of discoid receptacle of Cenangium, receptacles of Cenangium. (Slightly magnified) about 300 diam. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 229 represented in Jig. 150. The central portion of the disc is lined by an ascophorous mem- brane. The overhanging marginal fold still exhibits the filaments bearing spermatia, which characterised the earlier condition of the receptacle. Our authors are inclined to admit that the spermatia are to be considered as a male product, and the whole organ as analo- gous to a hermaphrodite inflorescence. The relative positions of the spermatia and thecae seem admirably adapted to insure their con- tact with each other. 44. We now pass to the Lichens, with re- spect to which the greater part of our informa- tion is again owing to the researches of MM. Tulasne.* In these plants, as in the Fungi, the germination of the spore consists in the emission of a hollow filament from some part of its surface. This filament which is simply an extension of the spore-membrane, branches repeatedly and spreads over the surface, on which the spore has been sown ; at the same time it divides by numerous septa, which occur at irregular intervals. By the intertwining of the resulting ramifications, a stroma is formed, to which the term hypo- thallus is applied, and which constitutes the vegetative system of the future lichen. So far the development is the same as the Fungi. At a longer or shorter period after the forma- tion of the hypothallus, we begin to observe upon its surface a whitish layer of spheroidal cellules, intimately united with each other, as well as with the filaments from which they take their origin. This layer serves as the groundwork for a second formation of glo- bular cells. These are distinguished from their predecessors, as well by the regularity of their form, as by the granules of chlorophylle which they contain. They are called gonidia, and are peculiar to the Lichens, among which their occurrence is almost constant. 45. Such is the origin of the thallus, which, although, at first sight, it appears to consti- tute the whole plant, forms only a part, and that not the most essential part of its vege- tative system. In the Verrucariae, the most simply organised Lichens with which we are acquainted, it does not attain to any higher development than that above described. The receptacles (apothecia), which closely resemble those of a Sphoeria, are formed upon the surface of the hypothallus, which can only be distinguished from the stroma of the Fungus by the presence of scattered col- lections of gonidia. In the more complicated fpliaceous Lichens, such as Parmelia, the mature thallus is formed of two kinds of tissues, the medullary and the cortical. The cortical tissue forms two layers — an inferior and superior — and consists of thick-walled cells intimately adherent to each other, and resembling those of analogous structure, which so often form the peridia of the higher * Mem. pour servir a 1'Histoire organographique et phvsiologique des Lichens, Ann. des Sc Xat. 3me s" t. xvii. pp. 5. and 173. Fungi. From the surface of the inferior layer are given off numerous laminar root-like Fig. 151. Vertical section of the apothecium of a Lichen (Par- melia aipolia) and of the subjacent tissue of the thallus, 200 diam. a, Lamina proligera, consisting of thecae and para- physes ; 6, tissue of thick- walled cells continuous with the cortical tissue of the thallus. Subjacent to this, but separated by an irregular line of gonidia, is the medullary" filamentous layer. appendages: The medullary substance con- sists of a filamentous central layer, the elements of which resemble those of the hypothallus, and are directly continuous with them ; on either side of this layer, between it and the cortex, or rather embedded in its substance, are the gonidia, which form a green tissue, distinguishable by the naked eye. To these a special function is assigned, which shall be noticed at the conclusion of the article under the head of Gemmation. 46. We have next to describe the recepta- cles, within or upon which the spores or spore- like organs (spermatia and stylospores) are produced. Of these there are three varieties, to which the terms apothecia, spermogonite, and pycnides, have been applied. The most common form of the apothecium is that of a disc, which may be plane, convex or cup- shaped. This form is that which charac- terises the gymnocarpons Lichens. In the Angiocarpea, the organ is closed upwards, its superior surface becoming internal, so as to form a conceptacle like that of the Pyreno- mycetes, the form of which is subject to considerable variation. In either case, it is composed of two layers, the inferior or ex- ternal, being formed of thick-walled cells which are soldered together, and resemble those of the epidermal layers of the thallus. The superior or internal layer is called the lanwia proligera. It is formed of two kinds Q 3 230 REPRODUCTION, VEGETABLE (VEGETABLE OVUM). of elements : first, the paraphyses, which are linear, claviform filaments, composed of from Fig. 152. Section of fruitful ihallus of Sticta pulmonacea, about 20 diam. a, discoid apothecium. The vertical lines indicate the lamina proligera ; s, spermogonia containing spermatia ; i, empty spermogonia. six to eight cylindrical cells, joined end to end; and secondly, the thecce, which are obovate vesicles, each containing, almost in- variably, eight spores. These elements are arranged side by side, their long diameters being perpendicular to the surface of the apothecium. They appear to be glued toge- ther, even in the fully formed apothecia, by an intermediary gelatinous substance, which, however, there is good reason for supposing to be nothing more than a thickening of the external membrane, from which it cannot be distinguished, either in respect of its chemical or other characters. Iodine colours this substance, as well as the external mem- branes of thecae and paraphyses, blue, without the addition of sulphuric acid. In the early condition, the cavities of the thecae are occupied by a yellow, plastic material, out of which the spores are afterwards formed. The thickness of the external starchy mem- brane is at this period relatively more consi- derable than later; as the spores increase in size, it gradually diminishes. The struc- ture of the fully formed spore is best ob- served in those species in which it is largest. The spore-membrane, of considerable pro- portional thickness, is smooth and semi- transparent, wholly unaltered by iodine and sulphuric acid. The contents consist partly of mucous granules, which are coloured brown by iodine, partly of yellowish oil globules. The whole is usually invested, even after its escape from the theca, with the still adherent remains of the inner proto- plasmic layer, by which it was immediately surrounded. In form, the spores are most frequently ellipsoid and unilocular. In other instances, however, they are divided by one or more partitions. This division is either complete, so that the spore resembles two obovate cells joined by their larger ends ; or incomplete, the septa being in some cases scarcely distinguishable from the protoplasmic contents of the central cavity. 47. The spores are discharged from the thecae with an elastic force often sufficient to project them to a considerable height above the surface of the apothecium ; a fact, which M. Tulasne seems to have shown to be dependent on the great capability of imbibing moisture possessed by the lamina proligera, which much exceeds that of the tissue imme- diately subjacent. It resembles altogether what is observed in the Pezizas, whose spores, it is well known, are projected with such force as to form a cloud above the receptacle. 48. We have next to notice the remarkable organs which Itzigsohn* described as the antheridia of the Lichens, and to which he was the first to assign a distinct function. They had been previously adverted to by several botanists, and had been usually considered as parasitical Pyrenomycetes, which they closely resemble. They consist of conceptacles em - bedded below the upper surface of the thallus ; their presence is revealed by the appearance of blackish, projecting points, scattered at irregular intervals. The form of these organs, Spermogonia of Scutula Wattrothii, 150 diam. The spermatia are seen escaping in numbers from the apicial aperture of the organ. which MM. Tulasne have named spermo- goniae, is globular, ellipsoid, or oblong. Their external envelope is frequently hard and crustaceous, and usually blackish. The cavity may be simple or multiple ; in the latter case all the compartments or sinuses open at one ostiole. The whole of the cavity is occupied by a filamentous tissue, which consists of two elements — viz., spermatia and the organs on which they are supported. The latter are simple or branched filaments, which are usu- ally undivided, but occasionally jointed. They originate from the inner surface of the con- ceptacles. At their summits and articulations, they bear the spermatia, which are straight or curved linear organs of great tenuity, and are motionless. They are coloured brown by iodine ; both the spermatia and filaments are embedded in an abundant mucilage ; many of the former are sterile, and are so long that they project beyond the opening of the con- ceptacle like a kind of cirrhus. The whole structure corresponds in every respect with that of the spermatia-bearing conceptacles of the Discomycetes and Pyrenomycetes. 49. To a third variety of conceptacle, MM. Tulasne have assigned the title of pycnidis, This organ, although it has only been ob- served in two genera, Abrothallus and Scutula, * Bot. Zeitung. 1850. S. 913. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). is no less important, as forming another con- necting link between the Lichens and Fungi. The special characteristic of these organs is to be found in their containing, instead of thecae or paraphyses, stylospores, supported on stipitiform pedicles or basidia. In their Pycnidis of the same, about 150 diam. The stylospores are escaping from the upper ori- fice of the organ. (The figures from 143 to 154 in- clusive, are after Tuiasne.) general form they resemble the spennogoniae, but their walls are thicker.and they are larger. Like them they are provided with a vertical ostiole. The stylospores are oblong, cylin- drical bodies, more than twice the length of the spermatia (from -^^ to -^^ °f an inch), obtuse at both ends, very slightly curved, colourless, and containing only granular pro- toplasma. They are supported on pedicles, which have the same arrangements as in the spermogoniae. They are simple, linear tubular filaments, which taper towards their extre- mities. Just as the spermogoniae correspond to the spermatium-bearing organs of the Fungi, the pycnides correspond to those receptacles, containing stylospores, which we have had occasion to describe both in the Discomycetes and Pyrenomycetes. 50. Summary. — The reproductive organs of the Fungi and Lichens are of five kinds : — 1. Sporules, which are formed by the con- striction and subsequent separation of the extremity of a simple cylindrical filament ; 2. Spermatia with their supporting pedicles ; 3. Stylospores, with their styles ; 4. Thecae or asci; o. Basidia, with their basidiospores. Of these the last mentioned are to be found only, as we know at present, in Fungi which are provided with no other reproductive organ. The first four, on the other hand, all of them occur in plants belonging to one family of Fungi — viz. the Disco- and Pjreno-mycetes : they also all occur, with the exception of the first, among the Lichens. They may be arranged, as regards the complexity of their form and structure, in the order in which they 231 are placed above, the simple acrogenous sporule standing first. A similar arrangement may also be adopted in the description of the corresponding varieties in the reproductive phenomena which manifest themselves in con- nection with each variety of spore-like body. As regards the first of these, nothing further need be said, as the formation of the sporule by division, as described above, constitutes the whole reproductive process. It is exem- plified in the stroma of a Sphoeria, when in a condition corresponding to that which cha- racterises a Melanconium. The spermatium is found only in a special receptacle, the general form and structure of which remain always the same, as in the Cytispora-like capsule of the Disco- and Pyreno-mycetes and the spermogoniae of the Lichens. The stylospores are also formed in special organs (pycnides, and the corresponding organs among the Fungi), which differ from the last only as regards the structure of the parts upon which the spore is immediately sup- ported. Lastly, the receptacles which bear thecae are of larger size, more complicated in their structure, and later in making their appearance than any of the rest, as in the instance of the disc of Peziza, the closed re- ceptacle of Sphceria, and the apothecium of the Lichens. 51. The Pyreno- and Disco-mycetes are, as we have seen, so closely allied to the Lichens as regards their reproductive organs, that the characters of the two families seem in this respect to merge into each other. The dis- tinction is to be sought in the vegetative system. The thallus of the Lichen differs from the thallus-like stroma of the Fungus in its possessing two additional elements, the cortical layer and the gonidia. We observe their first appearance in the mosc simple form in Verrucaria. 52. There is as yet no sufficient ground for definitively concluding that the reproductive functions of the asci and spermatia are com- plementary to each other ; or, in other words, that these organs are sexual. There is, how- ever, good reason for considering it probable; first, because, when spermatia and asci are produced on the same mycelium, the former always precede the latter in their develop- ment by a considerable period, just as among the higher Cryptogamia, the antheridia precede the archegonia ; and, secondly, because the organs on which the spermatia are supported, and the asci, stand in an anatomical relation to each other, and to the receptacle within or upon which they are formed, which closely resembles those of the antheridia and epispores of the Fuci, or of the antheridia and tetraspores of the Florideae. We are well aware that these analogies do not afford the slightest proof of an actual correspondence between the organs in question. All more direct evidence, however, is absent ; no observations have been made to show that the spermatia or stylospores exercise any influence on the thecae or their contents, and on these important points, therefore, we must look to further ob- Q4 232 REPRODUCTION, VEGETABLE (VEGETABLE OVUM). servations for the grounds on which an opinion may be formed. 53. The fifth and last variety of reproductive organ mentioned above, is the basidium. The Mushrooms, along with another group of Fungi, which is distinguished by the possession of loculate receptacles, each loculus of which is lined with a hymenium, as e.g. Lycoperdon, include nearly all of the genera in which it occurs, and form Leveille's order, Basidio- sporea3. The order is a very natural one, and between it, and any of those which are most closely related to it, we can find no intermediate forms which at present might serve as guides in comparing the reproductive organs of the one with those of the other. The basfdiospore is distinguished from all the other acrogenous forms (stylospores, sper- matia), by well-marked and easily-defined characters — viz. first, by its much greater complexity of structure ; and, secondly, by the very peculiar and uniform arrangement, according to which the spores are developed in fours at the summits of the basidia. SECOND PART. HIGHER CRYPTOGAMIA AND PHANEROGAMIA. 54. In the attempt which we have made in the preceding sections to discover the order of succession in which nature has arranged the various families included among the Algae, Fungi, and Lichens, we have en- countered difficulties at every step. The extension of the same inquiry to the higher Cryptogamia and Phanerogamia is much more satisfactory in its results. " The comparison of the history of the development of the leafy Mosses and Hepaticae on the one hand, and of the Equisetaceae, Rhizocarpeae, and Lycopodiaceae on the other," says Hofmeister, " has shown the most complete correspondence of the formation of the fruit of the one with the formation of the embryo of the other. The archegonium of the Mosses, the organ within which the rudiment of the fruit (Fruchtanlage) is formed, has a structure altogether similar to that of the archegonium of the Ferns (in the widest sense) — to that part of the prothallium in whose interior the embryo of the frond-bearing plant originates, In both of these large groups of the higher Cryptogamia, we have a single cell, originating freely within the larger central cell of the archegonium, by the constantly repeated divi- sions of which, in the Mosses, the fruit — in the Ferns, the leafy plant, takes its origin. In both cases the division of this cell fails to take place, and the archegonium aborts, if the spermatic filaments (Saamenfaden) do not reach it at the moment that its summit gives way." * 55. The higher Cryptogamia and Phanero- * Hofmeister, Vergleichende Untersuchungen der Keimung, Entfaltung u. Fruclitbildung hoherer Cryptogamen. p. 139. Leipzig, 1851. gamia form a series, which, commencing with the frondose or membranous Hepaticae, ascends through the Jungermanniae and Marchantiae to the true Mosses. At this point, the thread is interrupted, but is easily resumed, and fol- lowed through the Ferns and Lycopodiaceae to the Rhizocarpeas. Between these last and the Phanerogamiae, there is again an interval of obscurity, which is succeeded in the latter by a new order of phenomena. The plants belonging to the series before us are charac- terised by their displaying a regular alternation of two generations which differ widely in their organisation. Of these, the first, taking its origin from the germinating spore, develops two kinds of organs, the reproductive func- tions of which are complementary to each other. One of these (archegonium) is destined for the reception of a germ-cell, while the other (antheridium) sets free a number of cor- puscles closely resembling the antherozoids of Chara, which have been already described. It is from this germ-cell that the second gene- ration commences its existence ; its develop- ment being, as there is now every reason to believe, dependent on the actual contact of the antherozoids. It differs completely in form and structure from its parent, and pos- sesses only one kind of reproductive organ. This organ throws off germs (spores), each of which is capable, independently of any ex- ternal influences, except those of heat and moisture, of transforming itself into a new individual. This in its turn produces pistillidia and antheriditty and thus forms the starting point of a new development. 56. Supposing the history of the develop- ment of the plants under consideration to com- mence with the germination of the spore, and terminate with its arrival at maturity, it may be divided into two periods. Of these the first is completed in the full development of the archegonia and pistillidia, and the com- bination of their products, so as to form an embryo ; while the second terminates in the full development and distribution of the spores. 57. Among the lower Hepaticae, the vegeta- tive system (frond) consists of a simple mem- branous expansion, which may be considered equivalent to what would result from the soldering or fusing together of the leaves and stem of a more highly developed plant. The frond is of various forms — always originally linear, and lengthens at one (the anterior) extremity only. At the other end, which is eajrliest formed, cessation of vegetation, and marcescence are constantly taking place. The adult plant assumes very various forms, which arise from the repeated bifurcation of the original riband-shaped shoot. In the plant, the development of which we are about to describe (Anthoceros laevis) as one of the most simple of the Hepaticae in its structures, the fully-formed frond is a lobed expansion of succulent, dark-green parenchyma, the general contour of which is circular. We shall divide the history of its development into two periods, corresponding with those laid down in the last paragraph. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 58. First period.* — From the germination of the spore arises a tubular filament, which is converted directly, by successive divisions, into a simple riband-like frond, with a notch in its anterior margin, containing a young shoot. At whatever age the plant be ob- served, the actively growing portions are shoots which resemble the spore plant in form and structure, and it is at various points of the upper surface of these shoots that the reproductive organs are developed. 59. The development of the antheridia com- mences in the still very young shoot, by the separation "of a circular group of about sixteen of the superficial layer of cells from those of the tissue below it. There results a small lentil-shaped lacuna in the parenchyma, which Fig. 155. Section of young shoot of Anthoceros levis, passing through the lacuna in which the antheridia are deve- loped. The rudiments of the antheridia springing from its floor, project upwards into its cavity. 50 diam. is filled with watery fluid, and roofed over by the cellular layer above mentioned." Each of the cells forming the floor of the lacuna, is divided by two septa, one parallel to the axis of the frond, and perpendicular to its surface, the other also perpendicular, but cutting the first at riijht angles. The membrane of each of the resulting small cells buds out upwards, so as to project into the lacuna, and soon after, the upper projecting portion is cut off from the rest by a transverse septum, and becomes the parent cell of the antheridium. A second septum is then formed above the first, and parallel to it. This is succeeded by a third, which is inclined to the horizon at a small angle. Above it is a fourth, similarly inclined, but in the opposite direction ; next follows a fifth, parallel to the third, and so on alter- nately. In this manner is formed a cylindrical papilla, consisting of two vertical series of cells, each of which is a segment of a cylinder. Each is next bisected by a radiating vertical septum, so that the papilla is now formed of four in- stead of two vertical columns. The penul- timate cell of one of these columns next * The following description is abridged from Hofmelster in loc. cit. pp. 4 — 9. 233 divides by a vertical septum, parallel to a plane touching the centre of its outer sur- face. This meets the perpendicular wall last formed at 45°, and divides the cell into an external tetrahedral, and an internal three-sided compartment. The latter divides twice by septa, which cross each other at right angles, so as to form a central group, which, as it rapidly enlarges, causes the four less actively growing cells by which it is sur- rounded to assume a tabular form. In its further development it is converted into a mass of very numerous and minute regularly- arranged tessellar cells, in each of which is found " a lentil-shaped vesicle which occupies the greater part of its cavity." Shortly before the antheridium arrives at maturity, the mem- brane of the cells disappears ; the vesicles float free, and there is now found rolled up in each, a spiral fibre of from 2% to 3 coils, which is coloured yellow by iodine. The ripe antheridium presents the. general form and ap- pearance shown in fig. 156. The cellular mem- Fig. 156. a, diagram of antheriditun of the same, 250 diam. ; b, lenticular cellules containing antherozoids, 600 diam. brane, resulting from successive division of the four cells, which originally surrounded the central mass, gives way at the apex of the organ. In the meantime, the layer of cells which roofed over the lacuna has split open. The escaped spiral filaments (antherozoids), as seen under the microscope, soon after lose the vesicles in which they were enclosed ; " each slowly revolving round its own axis, lazily progresses in the surrounding water." 60. The development of the archegonia in An- thoceros differs from that of all other Hepaticae in its much greater simplicity. A single row of cells commencing at the upper surface of the young shoot, and directed towards its interior, becomes distinguished from those surrounding it by the quantity of granular mucus which it contains. The lowest cell of the series becomes larger than the rest. In its interior a daughter cell (germ-cell) which nearly occupies its cavity, is formed around a pre-existing central nucleus. The contiguous walls of the cells forming the remainder of the series are absorbed. Hence results a canal which leads from the surface to the cavity of the basal cell. It is difficult to believe that an arrangement so remarkable can have any 234- REPRODUCTION, VEGETABLE (VEGETABLE OVUM). other object than the admission of the anthe- rozoicls. fe. 157. Archegonium of the same, 300 diam. a, origin of the archegonium ; the shaded vertical row of cells constitutes the rudiment of the organ ; &, archegonium immediately before impregnation. 61. Second period. — Fructification of the ar- chegonia. In the greater number of archego- nia, development ceases at the point above described. In those in which the germ-cell has received the influences necessary for its fructification, this last-named body enlarges rapidly, and very soon divides by a slightly Fig. 158. Archegonium of the same immediately after impregna- tion. The germ-cell has divided by an oblique septum. oblique septum, which is followed by a number of others, alternately inclined in opposite directions. This results in an egg-shaped body, perfectly separable from the surround- ing tissues. The last-formed summit-cell now divides by a septum which is inclined not in the opposite direction, but in a direction at right angles to that of its predecessor. This is followed by a second in the same relation ; that by a third, and so on continuously. The cylindrical rudiment now consists of four columns of cells, each of which is divided symmetrically by a vertical septum, into an external trapezoid and an internal three-sided cell. The former again divides, first, by a ver- tical, then by a horizontal septum, both of them perpendicular to the surface of the rudi- ment, which now consists of four central cel- lular columns, which are enclosed in eight others formed of trapezoidal cells. These last divide by vertical septa, alternately paral- lel and perpendicular to the external surface, by means of which the rudiment gradually thickens. This process goes on much more actively at the lower than at the upper or middle portion, in consequence of which it becomes club-shaped ; its swollen base being embedded in the parenchyma of the stem of the parent, and causes absorption of its cells. The cells in the neighbourhood of the ori- ginally six-sided canal leading to the germ, have in the meantime rapidly multiplied. The upper part of the canal now encloses the growing extremity of the rudiment, which, however, is separated from it by a quantity of fluid. It opens at the apex of a nipple-shaped projection of the upper surface of the frond, by a narrow aperture through which the coni- cal upper extremity of the rudiment protrudes, and, as it rises, usually carries with it the remains of the cells immediately surrounding the narrow channel through which it has forced its way. It now presents the horn-like form, characteristic of the mature fruit, from which the generic name of Anthoceros is derived. 62. Changes preparatory to the development of the spores. — An axile cylindrical column, consisting of four cellular piles, becomes dis- tinguished from those surrounding it by the cessation of the division of its cells by hori- zontal septa. In the layer which immediately surrounds it, on the contrary, division by hori- zontal septa occurs twice as frequently as in any other portion of the fruit. The hitherto homogeneous parenchyma becomes in con- Fig. 159. Section of half-ripe fruit of the same, 120 diam. The axile column of elongated cells is the columella. Next to it are two dark spaces corresponding to a cavity, which contains at its upper part parent cells of spores and elaters, — inferiorly the tubular cells from which they originate ; a, capsule. sequence distinguishable into three portions — an external, of about five concentric layers of trapezoidal cells (the future capsule), an axile portion of elongated columnar cells (the future columella), and, interposed be- tween these, a single layer of tabular cells, whose greater surfaces are horizontal (the cells from which are formed the spores and elaters). 63. Development of the spores. — Those of the cells last mentioned, which are destined to become the mother-cells of spores, soon be- come detached from their neighbours, and assume a spherical form. Each at first con- tains a large central nucleolated nucleus, and REPRODUCTION, VEGETABLE (VEGETABLE OVUM). a quantity of granular mucus. Soon this last arranges itself in two masses, at opposite Fig. 160. Original parent-cell of spores of the same, 500 diam. sides of the central nucleus. Each of these masses is transformed into a new nucleus, from which radiating threads of mucus stretch to the internal surface of the corresponding half of the cell. Each new nucleus is, when fully formed, vesicular, possessing a membrane of extreme delicacy, and is surrounded by a layer of protoplasma. At a later period its contour becomes cloudy and indistinct ; this change being preparatory to a second division, which results in the formation of four new nuclei similar to the first two; these The same, containing four vesicular nuclei, soon place themselves in such a manner, that each would occupy one angle of a regular tetrahedron contained in the parent cell. Up to this point the original central nucleus has remained ; it now disappears, and six septa are formed simultaneously, which radiate from the centre to the circumference, one between every two nuclei, in such a manner as to divide the parent cell into four compartments, which are the special parent cells of the spores. Fig. 162. The same, divided into four compartments. (The above, from 155 to 162, inclusive, are after Hofmeister.) In each new cell, after this wall has become thickened by the deposition of a gelatinous material on its inner surface, a spore is formed, which, even at the first appearance of its membrane, occupies the whole cavity. As it approaches maturity, it assumes a brownish yellow colour, its external surface remaining perfectly smooth. In those of the cells of the middle layer of the half-ripe fruit, which are destined to the formation of the so-called elaters, the tubular form is permanent. In 235 each cell the nucleus disappears, and is re- placed by two others, between which a per- pendicular septum is formed. From a repeti- tion of the same process, there results a cylindrical body consisting of a series of four cells, the fully formed elater. 64. No sooner are the spores of the upper part of the capsule ripe, than it splits into two valves ; dehiscence commences at the apex, leaving, as it proceeds, the columella with the loosely attached spores and elaters. 65. Jungermannicef rondos te. — From Antho- ceros we pass to a group of plants, which, while they resemble it in their mode of growth, differ from it considerably in the form of their antheridia and archegonia, and still more in that of the organs in which they are contained. Here as in Anthoceros we follow the descrip- tion of Hofmeister (Pellia epiphylla).* 66. First period. — Germination of the spores. — The spore is an ovoid cell, divided into four by three transverse septa, and enclosed in a finely granular external membrane. Of the four cavities, one of the terminal ones dis- tinguishes itself from the rest by the small quantity of chorophylle which it contains. This cavity, or rather the cell which it represents, develops in germination, to the first hair-like roots; while the others, by successive divisions by septa in the direction of the long axis of the spore, form the rudi- mentary flattened stem of the young plant. 67. The antheridia. — The rudiments of the antheridia make their appearance as club- shaped projections of the upper surface of the young spring shoots. Each such projec- tion originates from a single cell of the super- ficial layer by a mode of division which cor- responds in every respect with that described in Anthoceros (§ 59). The completely formed antheridium consists of a globular mass of very small four-sided tessellar, cells, which is surrounded by an outer layer of about twenty flattened cells, containing chlorophylle granules in contact with each other by their margins ; the whole is supported on a very short stalk, consisting of only four cells. Each of the small cells contains a lentil-shaped vesicle, within which a spiral fibre is rolled up. This fibre moves with great activity for about ten minutes after its escape, revolving round its own axis, and at the same time progressing rapidly. The posterior extremity is slightly thickened, while from the anterior which tapers off gradually to a point, there ema- nate two long and delicate cilia, like those of the antherozoids of Chara. These, as well as the slender prolongation of the tail, mani- fest an active " winding screw-like " motion. These phenomena remain in perfection only for about ten minutes after the escape of the filament. 68. Archegonia. — The rudiments of the ar- chegonia make their appearance as oval cellular bodies (from four to twelve in number) in the notch, which in Pellia, as in other fron- dose Hepaticae, is found in the anterior margin * Hofmeister, foe. cit. pp. 10—20. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 236 of the young shoot. Soon after their origin, there is formed, by the continued growth of Fig. 163. Antherozoids of PeUia, 400 diam. (Thuret.) the shoot below them, a thin laminar prolong- ation upon the surface of which they are sup- ported. By a process of cell-division resem- bling that observed in the development of the antheridia of Anthoceros, each rudiment is converted into a cylinder, rounded above and consisting of a single central cellular column, surrounded by a single layer, which is formed of four perpendicular series of flattened cells in contact with each other by their edges. The cells of the central column contain granular mucus, in which ve- sicular nuclei are embedded. As the arche- gonium becomes fully formed, the lowest cell in the series, as well as its nucleus, enlarges, and the cells of the outer wall in its neigh- bourhood rapidly multiply, so that the organ becomes swollen out at its lower part. The development is completed by the disappearance of the transverse septa, which separate the cavities of the cells forming the central column. In this manner is produced an axile channel, closed above, and terminating below in a flask-shaped dilatation, in which Fig. 164. Archegonium of Jungermannia bivaricata at period of impregnation, 400 diam. Cellules containing antherozoids are observed at the entrance of the canal. the enlarged nucleus of the basal cell (germ- cell) is contained. Soon the cells forming the summit of the archegonium give way, so as to open a communication between its cavity and the external atmosphere. 69. Second period. — Development of the em- bryo.— In consequence, as there is every reason to believe, of the entranceof the spiral filaments into the cavity of the archegonium, the germ- cell is divided by a tranverse septum into a larger inferior and smaller superior (hemi- spherical) portion. This last next divides by two perpendicular septa crossing each other at right angles, which are succeeded by a third, which is horizontal. This is succeeded by others parallel to it, each new septum being placed immediately above its predecessor. Hence results a cellular cylinder, the rounded summit of which always consists of four cells, divided from each other by crucial septa. By successive cell-divisions, this body becomes a pear-shaped cellular mass. Afterward by the lengthening of its middle third, the cylindrical stalk of the perfect fruit is formed, and still later from the lower third springs a cup- shaped sheath, the margin of which reaches to about a third of the length attained by the stalk of the fruit before it has escaped from its calyptra. 70. Changes preparatory to the development of the spores. — At an early period, when the young fruit is still pear-shaped, its rounded up- per end (the future capsule) manifests peculi- arities in its intimate structure. The cells of its superficial layer are divided repeatedly by septa perpendicular to the surface, while those which they enclose gradually enlarge without dividing. The result of this process is the formation of a central mass of large dodecahe- dral cells (parent cells of the spores and elaters), which is surrounded by a single layer of tabular cells of not more than a quarter their breadth (the future wall of the capsule). As the development proceeds, the walls of the central cells become thickened by the deposit of a gelatinous material on their internal sur- faces. This material, which is coloured violet by iodine, swells out, and finally dissolves, on the addition of water, the globular primordial vesicle, which occupies the centre of the cells, being brought into view. Still later both the cell membranes and their gelatinous linings disappear, and the primordial membranes are left, lying in the cavity of the young capsule. Soon after they clothe themselves with new membranes of cellulose, and assume forms, which differ according as they are destined to become parent cells of spores or elaters. Those of the newly formed cells which are to be elaters, assume the form of spindles. They are found partly grouped round the axis of the capsule, partly in series which radiate from it towards the circumference. The future parent cells retain only for a short time their globular contour : soon four projections of the mem- brane of each cell become visible, each of which would correspond in position to one of the angles of a regular tetrahedron contained in the parent cell. These projections increase so rapidly, that in a short time the whole presents the appearance of four egg-shaped REPRODUCTION, VEGETABLE (VEGETABLE OVUM). sacculi blended together by their smaller ends in such a manner that their axes meet at a central point, each forming with all the rest angles of 120°. The cell-wall now becomes thickened by the deposition of a granular material on its inner surface, which takes place most rapidly along the linear ridges which separate the sacculi. [n thi» manner six imperfect dissepiments are formed, which stretch from the ridges towards the centre, and encroach so far on 'the central cavity, that it now communicates with the cavities of the sacculi only by four narrow circular channels. These changes are followed by the formation in each sacculus of a delicate vesicle (the spore) completely filling the cavity of each. No sooner has this taken place than those por- tions of the parent cell which correspond to the sacculi dissolve and disappear, the four oval spores remaining attached for several days to the still permanent tetrahedral cen- tral portion, which consists of vitreous cellu- lose. The central nucleus of each spore now disappears, and is replaced by two others, around which the mucous and chlorophylle granules group themselves. A septum is soon after formed between them, dividing the spore into two halves, in each of which the process is repeated. In the meantime the coloured external membrane is secreted on its external surface. The ripening of the capsule and consequent scattering of the spores takes place in spring, a year after the development of the archegonium within which the fruit originated. 71. Our limits will not permit us to enter upon the history of the development in other families of Hepaticae. In the higher Jungermannias, which are provided with a distinct stem, as well as with regularly formed and symmetrically arranged leaves, it closely corresponds to that of Pellia. In the Mar- chantias, in which we have again a frondose stem, we have considerable differences. The antheridia are found on special receptacles of various forms, sometimes stalked capitula, concave superiorly, like the stalked apothecia of some Lichens (Marchantia polymorpha), sometimes sessile. However much the general form may vary, they agree in their relation to the antheridia. These last are flask -shaped bags, and always completely im- mersed in the parenchyma subjacent to the upper surface of the receptacle. This surface is always found to be scattered over with nipple-shaped elevations. At the summit of each an aperture is observable — the termina- tion of the long and narrow neck by which the cavity of the antheridium communicates with the surrounding medium. The fully formed antheridium consists of a central mass of quadrangular cells, which, surrounded by a single layer of others much larger and of a tabular form, is continued upwards so as to form the narrow neck ; the whole being closely invested by the parenchyma of the receptacle. Within each of the central cells is found a lentil-shaped vesicle containing a spiral filament, which only differs from those 237 described already in its greater minuteness. The archegonia of Marchantia are produced on the under surface of a somewhat umbrella- shaped, deeply lobed, stalked receptacle. This body corresponds in the mode in which it takes its origin from the notch in the anterior margin of the frond, with the ordinary vege- tative shoot, of which it is obviously a modifi- cation. Its development has been well de- scribed by M. Mirbel.* The structure of the archegonium, and the commencement of the development of the fruit, correspond very closely with what has been described in Pellia. The mode of formation of the spores and elaters differs, however, considerably. The latter, which in thelast-named plant, are nothing more than fusiform septate cells, attain in Marchantia, as well as in many Jungermanniae, a more complicated structure. Their develop- ment has been described in an admirable con- tribution by Mr. Henfrey, who finds that the young elaters are, like those of Pellia, elon- gated fusiform tubes, and contain at first only colourless protoplasma.-j- Soon after starch granules are deposited in their interior, and they are converted by a growth which is much more rapid in length than in breadth, into very slender, hollow filaments, attenuated at each closed extremity. Still later, the starch and protoplasma disappear, and at length faint streaks, denoting the nascent fibres, are to be perceived upon the walls. These become gradually more and more distinct, till, in the mature elaters, they present themselves as strong flattened bands. In Marchantia there are two fibres, which coil in opposite direc- tions, and are confluent by their ends at the extremities of the tubes in which they are contained. At the time of the scattering of the spores the cell-membrane gives way, and the elastic fibre rapidly uncoils, at the same time lengthening considerably. The parent cells of the spores in Marchantia are also, at an early period, fusiform. They are arranged side by side with the young elaters, from which they differ in being very much broader. Each of these cells is converted, by the forma- tion of transverse septa, into a series of four, which afterwards separate from each other. In each of the new cells, the protoplasma in- creases in quantity and assumes a yellow colour. Still later it begins to accumulate into four distinct masses, each of which be- comes invested in a cellulose membrane, and, after the solution of the membrane of the parent cell, assumes the structure and appear- ance of the ripe spore. 72. Mosses. — The Mosses are distinguished from the leafy Hepaticae, first, by differences in the structure and arrangement of the stem and leaves, involving greater complexity ; secondly, by the fact that the leafy axis is not developed directly from the spore, but, with the inter- vention of a confervoid structure (proto- * Recherches Anat. et Phys. sur le Marchantia, Mem. de 1'Acad. v. xiii. p. 380. t Transactions of Linnoean Society, vol. xxi. p. 106. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 238 nema),* resembling in all its relations to the future plant, the mycelium of the Fungi and Lichens. 73. First period. — Germination of the spore. ^ — The spore of the Mosses is a nucleated cell, the solid contents of which are granular, and consist of protein compounds, starch and dex- trine. From the budding out of its membrane, results a hollow filament, which, as it lengthens, divides by a succession of transverse septa. It then begins to branch in all directions, each branch resembling the parent, and rami- fying in the same manner. Hence results an entangled network of filaments of a brilliant green colour, which spreads over the moist surface on which the spores have been sown. At length some of the filaments are observed to give off lateral branches which differ from those previously formed in being more slender and containing less chlorophylle. In some of these the terminal cell, after dividing four or five times, becomes globular, and is transformed into the rudiment of a leafy axis. 74. Development of the antheridia and arche- gonia. — These organs are usually found in groups, which are situated either at the termi- nation of the stem or branches, or in the axils of the leaves. In either case they are surrounded (with the exception, in many genera, of the axillary antheridia) by special arrangements of modified leaves (involucres). Those involucres which surround the antheridia are called perigonia, and are composed of leaves much smaller than the ordinary leaves of the stem. Those leaves which enclose the archegonia, small at first, attain a large size as the fruit approaches maturity. In some (hermaphro- dite) mosses, both antheridia and archegonia are contained in one involucre. 75. In the very diminutive plants belonging to the genus Phascum, which we select as ex- amples on account of their great simplicity of structure, the groups of archegonia are termi- nal, those of antheridia usually axillary. The growing extremity of the stem (terminal bud) or axillary bud, when destined to bear repro- ductive organs, instead of developing to a new axis, becomes flattened in such a manner as to present a slightly convex disc, which takes the place of its conical growing extremity. It is upon the surface of this disc that the rudi- ments, whether of antheridia or of archegonia, originate, by a process precisely similar to that which we have described in the commencing development of the antheridia of Anthoceros. The rudiment consists, as in Anthoceros, of four columns of cells, combined so as to form a cylindrical club-shaped body. The development and ultimate form of the arche- goriium corresponds so completely with what has been described in the Jungermanniae, that * From the very recent observations of Gronland (Mem. sur la Germination des Spores de quelques Hepatiques, Ann. des Sc. Nat. 3m* S. xx.), it appears that among the higher Hepaticae with cut leaves, the first result of germination is always a branched and septate filamentous protonema, resembling that, of the Mosses in its relation to the leafy stem. f Hofmeister, loc. cit. pp. 65—71.; Bruch & Schimper, Bryologia Europaea, Fasc. i. p. 5. it is unnecessary to describe it. The fully formed antheridium of Phascum is a club- Fig. 165. Section of termination of fruitful stem of Phascum cuspidatum,oQ diam. On the right a female, on the left a male inflo- rescence. From the slightly convex surface which forms the summit of the stem, spring in the one case the archegonia, in the other the antheridia, along with numerous jointed fila- ments. shaped body of about the same length as the archegonium, and consists of a central mass of minute quadrangular cells, which is enclosed by a single layer of tabular cells, in contact with each other by their edges. Shortly be- fore the antheridium arrives at maturity, the quadrangular cells, each of which contains a spiral filament enclosed in a lentil-shaped vesicle, are dislocated. This is followed by the total disappearance of their membranes, so that the vesicles float free in the cavity of the now ripe antheridium. No sooner is this the case than the organ gives way at its summit, and discharges its contents in the form of an intestine-like coil of mucus, consisting of the lenticular vesicles with their contents. Soon after, this is dissolved, and the spiral filaments commence their active motions. 76. Development of the fruit. — The early stages correspond with those described in Pel- lia. At a period when the lower dilated portion of the archegonium is about five°times its ori- ginal length, the young fruit, which is a fusiform cellular body, does not occupy more than its upper half. In the meantime the cells form- ing the tissue subjacent to, or in the immediate neighbourhood of, the base of the fructified archegonium, have multiplied with such acti- vity, that the end of the stem has again assumed the form of a cone, on the summit of which the fruit is borne, while the aborted archegonia are scattered round its sides. In its further development, the fruit grows much more rapidlv in length than in breadth, and in con- sequence of its extension upwards being op- posed by the resistant structure of the canal of the archegonium, its lower end presses downwards in such a manner as to cause the absorption, not only of the cellular tissue of the archegonium, which is subjacent to it, but of that of the conical summit of the stem. In REPRODUCTION, VEGETABLE (VEGETABLE OVUM). this manner it becomes firmly implanted, the tissue which surrounds it assuming the form of a sheath, and receiving the name of vagi- nula. During this process, the dilated portion of the archegonium has increased in size, and has now attained about ten times its original length. Finally, it gives way at its line of junction with the vaginula, and is carried up- wards on the summit of the still lengthening fruit. 77. Development of the spores. — The upper portion of the cylindrical fruit, which is des- tined to become the capsule, begins, some time after the calyptra has given way, to dilate rapidly. Soon after there is formed, by the separation of the external and superficial lay- Fig. 166. Section of half -ripe fruit of the same, 50 diam. The globular dilatation exhibits the following parts : — a, the capsule. Within this, and separating it from the central portion, is a dark space, which corresponds to a cavity of the form of a hollow cylinder ; b, columella ; c, super- ficial layer of central portion ; d, remains of archegonium ; e, vaginula. (From fig. 164 to 166 from Hofmeister.) 239 diately after its division into two halves. On the surface of each half cellulose is secreted, so that the spherical cells which are thus formed possess a delicate cellulose external, and a very distinct inner membrane (primor- dial vesicle.) This last divides into four por- tions (the young spores), each of which becomes invested with a layer of cellulose. The ripe spore has been already described. The capsule now gives way at the line of its insertion on the pedicle which supports it. It is by the opening thus produced that the spores make their escape after the dislocation of the layers of cells immediately surrounding them. Phascum differs from all other genera in the absence of all trace of an operculum. 78. Ferns. — No two plants could be found which differ more completely from each other in the appearance which they present to the ordinary observer, than a Hepatica and a Fern, at the moment that the spores of each arrive at maturity ; yet, in the history of their organ- isation and development a very close corre- spondence exists. The immediate result of the germination of the spore of a Fern is a frond similar to that of the simpler forms of Hepatica ; on this frond antheridia and arche- gonia are formed. In each fructified arche- gonium, a central germ-cell is developed to a new individual, widely different in organisation from the parent. It, in its turn, produces spores, the germination of each of which is the commencement of a new circle of phenomena similar to the one which precedes it. Dividing this circle into two periods, as before, we have the following stages in the development. 79. First period.* — Germination of the spore. — The mature fern-spore consists of a delicate transparent vesicle, which is invested in a brown resistant external membrane. Germi- nation consists in the budding out of the trans- parent vesicle so as to form a nipple-shaped projection, which penetrates the external mem- brane. The projecting part divides repeatedly by transverse septa. About the same time a second budding out takes place in the oppo- site direction, which is destined to the forma- tion of a root. By the further growth of new cells, a flattened two-lobed organ is formed — the Prothallium. Fig. 167. ers of cells from the central portion, a cavity of the form of a hollow cylinder, the axis of which coincides with that of the fruit. At this stage, the central portion consists of an axile column of large cells, closely invested by a single layer of smaller ones (the columella) ; a superficial layer of cells, about four times as large as those last mentioned ; and lastly, between the two, a layer of nucleated cells, with granular contents, the primary parent cells of the spores. The development of these last consists in the disappearance of the nu- cleus of each, and the substitution for it of two others; this being accompanied or fol- lowed by the division of the primordial mem- brane into two new vesicles, each of which encloses a nucleus. A cellulose membrane is Early condition of prothallium of Gymnogramma now tormed at the surface of contact of the chrysophytta, about 20 diam. (Heafrey.) two vesicles by which the original cavity is bisected. In the cavity of each of the result- ing nucleated cells, two new ones make their appearance, apparently by contraction of the primordial membrane, either before or imme- 80. TJie antheridia. — The antheridia are situ- ate on the under surface of the prothallium, * Hofmeister, I c. pp. 78 — 82. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 240 and take their origin as follows. A hemisphe- rical projecting portion of one of the superfi- cial cells is cut off from the rest by a horizon- tal septum as in Anthoceros. This is divided by a single transverse septum. In the result- ing terminal cell a second septum is formed, inclined to the horizon at a small angle, which is followed by a third, inclined in the opposite direction. Both of the cells resulting from these divisions, and subjacent to the last-formed septa, are again divided by perpendicular septa coinciding with the axis of the papilliform rudiment. In one of the resulting cells there is then formed a perpendicular septum, which meets its predecessor at an angle of 45.° Hence results a club-shaped body, consisting of a four-sided central cell, filled with granular mucus, and enclosed by six others, having the following arrangement. Four of the form of segments of a hollow cylinder, which are in contact by their edges, surround the central cell on all sides. It is surmounted by a fifth, which is hemispherical (the terminal cell last formed). A sixth, the cell resulting from the first division by a horizontal septum, is cylin- drical, and serves as a pedicle on which the whole is supported. The central cell is con- verted by a successive division into a round group of dice-shaped cellules, in the interior of each of which a delicate lenticular vesicle is formed, which contains, rolled up in its in- terior, a spiral filament. The ripe antheridium bursts at its summit, and the escape of its contents is, as in the preceding cases, followed by the bursting of the vesicles, and the com- mencement of the active motions of the spiral Fig. 168. Aniheridia of Pteris aquilina, 260 diam. On the right is seen an antheridium from which cells containing antherozoids are escaping; in the centre another, which has not yet burst ; on the left a third, which has already discharged its contents. (Thuret). filaments (antherozoids.) In each filament the extremity which is directed forwards du- ring motion, is broader than any other part, while the opposite extremity (posterior) tapers off into a long filament. The anterior coil of the spiral bears on the surface furthest from its axis a number of delicate cilia. The motion of the antherozoid is of two kinds — of progression and of revolution round the axis of the spiral. 81. The archegonia. — At a period somewhat later than that at which the rudiments of the antheridia begin to appear, there commences on the inferior aspect of the prothallium, and in the immediate neighbourhood of the notch by which its anterior margin is bisected so as to form two lobes, an active development of new cells. The result of this is the formation of a cushion-like projection of the surface bor- dering the notch above mentioned, upon the anterior aspect of which the archegonia are formed. 82. Each archegonium takes its origin from a cell, which is distinguished from those sur- rounding it by the comparative abundance of granular mucus which it contains, and by the presence of a distinct central vesicular nucleus. This cell divides by a horizontal septum into a superior and an inferior portion. It is from the latter, which is hemispherical, that the papilla which forms the rudiment of the pro- jecting portion of the organs is formed. It consists, as in theHepaticae and Mosses, of four contiguous columns of cells, each of which is a half segment of a cylinder, the whole being surmounted by a hemispherical terminal cell. In the further development, varieties are often observed, even on the same prothallium. This is dependent on the mode in which the canal occupying the axis of the mature archegonium is produced. Most frequently a central column of cells is formed in exactly the same manner as an Anthoceros. The cells forming it are afterwards absorbed and dis- appear, leaving a four-sided canal. In the other case, the canal results simply from the separation of the four piles of cells along their common line of contact. This is the arrange- Fig. 169. Archegonivm of Aaplenium septentrionale, 250 diam. a, germ-cell enclosed in its parent-cell; the mem- brane of the latter is still perfect, and separates its cavity from b, the axial canal. (Hofmeister.) ment which occurs constantly among the Equisetaceae, Lycopodiaceae, and Rhizocar- peas. In reference to the mode of origin of the germ-cell, there is some difference of opi- nion. According to Hofmeister,* the cell which contains it originates by the formation of a tangental septum in the lowest of the cells, constituting one of the four columns of * Loc. cit. p. 80. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). which the rudiment is composed. According to Mr. Henfrey *, on the other hand, the germ- cell is contained in the superior, and conse- quently deeper, of the two portions into which the primary nucleated parent cell of the organ divides by a horizontal septum ; and is dis- tinguishable before the formation of the pa- pilia-like structure has commenced. This account of the matter is not only supported by analogy, but, as it appears to us, in a very marked manner by Hofmeister's own drawings. 83. The embryo. — Immediately after the en- trance of the spiral filaments into the cavity of the archegonium, the cells which immediately surround it multiply rapidly, in consequence of which the cushion-like projection of the in- ferior surface of the prothallium increases in size. At the same time the germ-cell is trans- formed into an irregularly egg-shaped body, which consists of minute cellules, and may be considered as the primary axis of the future fern. It originates in the same manner as the rudiment of the fruit of the Mosses and Hepaticac, and elongates by repeated divisions of a terminal cell by septa, inclined alter- nately in opposite directions. It consequently presents but one growing point, which is di- rected, not towards the orifice of the archego- nium, but, on the contrary, towards the centre of the cushion-like mass, by the cells of which it is surrounded. Soon after, however, there appears on the side of the egg-shaped embryo, which is directed towards the notch in the anterior margin of the prothallium, a second growing projection of its surface. This projection, at first conical, becomes, as it enlarges, compressed from above downwards. No sooner is this the case, than it bursts through the superficial cellular layer of the prothallium, at a point which is invariably a little anterior to the base of the archegonium — between it and the angle of the notch. It now assumes the form of a symmetrical leaf-like organ, and begins to project beyond the notch of the prothallium. The further development con- sists in the appearance in the axil of this primordial leaf, of a new axis, the permanent stem of the young plant. From this axis all the succeeding leaves take their origin, each diverging from its immediate predecessor at an angle of 60°. 84. Sporangia and spores. — At a point of the surface of the frond, which always cor- responds to the termination of a vascular bundle, a lacuna is formed under the epider- mal layer, by the separation of that structure from the subjacent tissue. The floor of this cavity consists of a pavement of tessellar cells, some of which grow out into nipple- shaped projections. In each of these, the projecting portion is separated from the rest by a horizontal septum, which is soon fol- lowed by several others superior and parallel to it. The last-formed terminal cell now en- larges, and assumes a globular form, and is converted by a process similar to that to be * On the Development of Ferns from their Spores' Trans, of Linnsean Society, vol. xxL p. 135. Supp. 241 described below in the rudimentary sporan- gium of Equisetum, into a central mass of nucleated cells, with grumous contents (parent cells), enclosed in a capsule formed of a single layer of others, which are tabular. In each parent cell, the central nucleus afterwards disappears, and is replaced by four others. This is followed by the division of the pri- mordial sac into four portions, around each of which a cellulose membrane is formed. This membrane becomes the epispore; a second (endospore), which is distinguished by its greater delicacy, being subsequently formed within it.* 85. EquisetacecE. — The history of the deve- lopment of the Equisetaceae corresponds in most respects with that of the Ferns. 86. First period.^ — Germination of the spore. — The spore of Equisetum consists, in its ripe condition, of a delicate, colourless internal vesicle, which is surrounded by a more or less resistant granular membrane, and contains a central nucleus, and a yellowish grumous fluid, in which swim oil and chlorophylle granules. The first change observed in germination con- sists in the division of the nucleus into two, and the subsequent formation of a septum between the two corresponding halves of the spore-cell. Of these halves, the larger con- tains nearly all the chlorophylle, and is de- veloped to the stem; the smaller,the con tents of which are almost colourless, is the commence- ment of the root. The prothallium, which results from repeated cell-division of the larger half, is an irregularly riband- shaped expan- sion, growing and branching repeatedly at the extremity furthest from its point of origin, and consisting of large, delicate-walled cells, containing much chlorophylle. One of the branches is usually observed to be larger than the rest, and it is upon it that the reproductive organs are formed. 87. Antheridium.—The rudimentary antheri- dium of Equisetum consists, like that of pre- ceding families, of a papilla, composed of four conjoined vertical piles of cells, each pair slightly overlapping the pair preceding it. In each of the cells constituting this rudiment a tangential wall is formed, dividing it into an inner three-sided, and an outer tabular cell. The inner cells, which form a central oval mass, are soon observed to be filled with finely granular mucus : the tabular cells, on the con- trary, contain chlorophylle, and form the wall of the future antheridium. The further de- velopment of the central mass corresponds entirely with what has been described in other families. The antherozoa are larger in Equi- setum than in any other known example. They originate by the deposition of a gela- tinous linear thickening, in the form of an imperfect ring, parallel to the plane surfaces of the discoid vesicles in which they are enclosed. When fully formed, they resemble, in almost * Schacht, Entwick. des Sporangiums einiger Farrnkraeuter Bot. Zeitung, 1849. p. 537. f Hofmeister, /. c. pp. 97—103. ; Milde, Entwieke- lungsgeschichte der Equiseten, &c. Bonn, 1852. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 242 every respect, those of the Ferns. The anthe- ridia of the Equisetaceae are placed, not upon Antheridia of Equisetum, 300 diam. c, ripe antheridium, from which the antherozoids are beginning to escape ; b, unripe autheridium. (Hofmeister.) the inferior surface, but along each margin of the principal branch of the prothallium.- 88. Archegonium. — The archegonia were first discovered and figured by Milde* in Equisetum Telmateia, and have been since more completely described by Hofmeisterf and BischofF;}: in two other species. The pro- jecting papilliform portion consists, according to the last-mentioned observer, of eight cells, of which the four lower, in apposition to each other, have the general form of truncated cones, each presenting two flattened surfaces by which it is united to its two neighbours. The upper, in the same relation to each other, are nearly cylindrical, but are slightly rounded at their summits. The axis of the organ is occupied by a quadrilateral intercellular passage. The whole is supported on a base, which consists of two or three rows of cells Fig. 171. superimposed upon each other, which com- bine to form a circular wall round a central cavity, which contains the germ, and is the termination of the quadrilateral canal. On the transformation of the germ-cell into the embryo, observations are as yet wanting. 89. Spores and sporangia. — The organs upon which the spore-cases are supported are ar- ranged in whorls round the upper part of the fruit-bearing stem. They seem to be modifications of the ordinary stem-leaves, on which account they have received the name of sporophylla. In its earliest condition, the sporophyllum is a cellular projection of the surface ; but, as it advances towards maturity, it assumes the form of a hexagonal disc Fig. 172. Archegonium of Equisetum Telmateia, 200 diam. The axial canal terminates in a spherical cavity, •which is deeply embedded in the tissue of the prothallium, and contains the germ-cell. (Bi- schoff.) * Zur Entwick. der Equiseten. Bot. Zeitung St. 32, 1852. f Beitrage zar Kenntnisse der GefUsskryptogamen (referred to by Bischoff in the following paper.). J Ann. des Sc. Nat. 3me S. t. xix. p. 234. (Ex- tract from Bot. Zeitung, St. 6. Feb. 1853.). Vertical section of one of the sporophylla of Equi- setum limosum, 100 diam. a, mature sporangium ; b, another in outline. The capsule of the sporangium is composed, when ripe, of the external layer of cells only, in conse- quence of the absorption of the two inner layers, which resemble in their structure those described more at length in the sporangium of Selaginella (§ 94.), and seem destined to afford the ma- terials for the rapid growth and development of the mother cells of the spores. attached by a pedicle at its centre. Upon the surface of the disc which faces the stem, the spore-cases are formed. Each spore-case originates as a little papilla, and consists of a large central cell, which is invested by a single layer of others of smaller size. As the organ enlarges, these last are transformed into a capsule consisting of three concentric layers, within which is enclosed a mass of cells exhibiting large central nuclei and grumous contents. In each of these cells the nucleus is afterwards replaced by two others similar to it, which almost fill the cavity. These, however, soon disappear, and now four globular nuclei, much smaller than their predecessors, present themselves, and are arranged, as in the Hepaticae, towards the four angles of a regular tetrahedron. Around each nucleus a tetrahedral cell is formed, within which, after it has become detached from its fellows, there is deposited on the inner surface of its membrane, a gelatinous transparent layer. Within this layer, and immediately surrounding the nucleus, may be distinguished the primordial vesicle, on the surface of which the cellulose membrane of the future spore is secreted, as well as the two parallel, elastic fibres by which it is surrounded. When the spore is ripe, these last, which are external to the REPRODUCTION, VEGETABLE (VEGETABLE OVUM). spore membrane, and consequently formed before it, line the inner surface of the parent Fig. 173. Development of parent cells of the spores of the same- a, one of the nucleated cells which constitute the central mass of the young sporangium; 6, the central nucleus has disappeared, and is replaced by four others, one of which is out of focus ; c, the cell is divided by six septa into four somewhat tetrahedral compartments. This ob- ject has by mistake been represented relatively smaller than the rest ; d, the four compartments (special parent cells of the spores), are about to separate from each other: e, mature special parent cell. In its interior we observe the nu- cleated spore, and between it and the membrane of the parent -cell, the coils of the two elastic fibres ; f, the free spore ; the spiral fibres, which remain for a short time after its escape from the parent-cell, attached by their middle points to its membrane, have disappeared. cell, from which the gelatinous thickening has now disappeared. Soon after, springing asunder from each other, they tear the membrane of the parent cell, retaining, how- ever, their central attachment to the surface of the spore. 90. Lycopodiacece* — The large spore (ma- crospore) of Selaginella, consists, when ripe, of an internal spherical vesicle of delicate structure (endospore), which is enclosed in a resistant epispore. The endospore contains a fluid, in which float mucous and oleaginous granules only, its nucleus having disappeared. On its surface are observed three linear projections, all of which converge towards one point, the summit of the spore. The epispore, a structure of later formation, is composed of two layers, the internal of which is distinguished from the other by its remarkable transparency. The external sur- face is scattered over with acuminated projec- tions, which are connected with each other by a network of minute ridges. 91. The development of the prothallium commences (usually several months after the macrospore has been sown) by the deposi- tion of several cells on the internal surface of the proper spore membrane, at a point subjacent to that towards which the three ex- ternal ridges converge. Whether these cells * Hofmeister, /. c. pp. 118—124. are originally developed in situ, from a single parent, or existed before, lying free in the cavity of the spore, is uncertain. Hofmeister inclines to the latter opinion. At first the prothallium is a cellular expansion of circular form,which enlarges by growth at its periphery, and lines the upper part of the proper mem- brane of the spore. At its centre it is of considerable thickness, and is composed of several layers of cells. Towards its margin it becomes gradually thinner and thinner, its two surfaces at last converging at a very acute angle, so as to become continuous with those of the spore membrane. 92. Archegonia.—The first-formed arche- gonium is always found to occupy the centre of the upper surface of the prothallium ; its successors surrounding it at various distances. A superficial cell, distinguished from its neighbours by the quantity of granules which it contains, is divided into two by a trans- verse septum. From the upper of the resulting compartments is developed a papilliform projection, which is composed, as in the Equi- setaceae, of two double pairs of cylindrical cells, surrounding an axial intercellular canal. In Fig. 174. Section of unimpregnated archegonium of Selaginella denticulata, containing the granular germ-cell, 400 diam. the lower is contained a vesicular nucleus, the germ-cell of the fully formed archegonium. Its cavity becomes continuous with the axial canal by the solution of its membrane." Fig. 175. Archegonium of the same immediately after impregna- tion, 600 diam. The germ-cell has enlarged considerably, and di- vided by a transverse septum. 93. The embryo. — About the time that the formation of archegonia is completed on the upper surface of the prothallium, there is developed, on its inferior aspect, a tissue composed of cells much larger than any of those previously existing. This tissue pro- jects, in the form of a cushion, into the cavity of the spore. In general one only of the many archegonia receives the necessary fructifying influence. In this the germ-cell divides re- peatedly by transverse septa, as the result R 2 REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 244 of which a structure is formed composed of a series of cylindrical cells placed end to end. The growing extremity of this body, the so-called suspensor, penetrates the single layer of cells which separate it from the in- ferior surface of the prothallium, and buries itself in the cushion^like mass. A new deve- lopment now commences in the terminal cell, which is divided by a succession of septa inclined alternately in opposite directions. 176, Egg-shaped rudiment of embryo of the same attached to the suspensor, from the terminal cell of which it has originated, 300 diam. From this results an egg-shaped body, the primary axis of the embryo, which, as it en- larges,'causes the absorption of the cells by which it is immediately surrounded. Soon after a new (secondary) axis is developed, Fig. 177. Section of contents of upper part of macrospore of the same, 120 diam. a, prothallium, continuous at its periphery with b, the original inner membrane of the spore ; c, cellular body subjacent to prothallium, which projects into the cavity of the spore; a, com- mencement of secondary axis of growth of the embrj'o ; below p are observed the remains of the archegonium within which the embryo origi- nated. Several other unfructified archegonia are seen in section. the direction of which (obliquely upward), is nearly opposite to that of its predecessor. It finally makes its escape from the cavity of the spore by penetrating the prothallium near its centre, bearing upon its summit the first pair of leaves of the young plant. 94-. Sporangia and spores. — The sporangia of Selaginella denticulata are formed in the axils of the leaves of the fertile branch, in the following manner. A superficial cell of the stem, the position of which is always imme- diately above the middle of the line of in- sertion of the leaf, is developed to a nipple- shaped projection. The centre of this body is occupied by a large cell, which is enclosed by a single layer of others, and supported Fig. 178. Two germ plants of Selaginella Martensi, which have taken their origin from a single macrospore, 5 diam. on a short pedicle. As it advances towards maturity, the spore-case consists of a capsule of three layers. Of these the external or epidermic, is composed of narrow prismatic cellules containing only a transparent fluid. The cells of the middle layer are tabular, and contain starch granules, while those most internal are narrow and somewhat columnar, with very delicate walls. Within this capsule is enclosed a central mass of larger cells, which exhibit central nuclei and granular contents. These, which are the parent cells of the spores, are at first intimately united, but afterwards lie loose in the cavity of the spore-case. Up to this point the development of all the sporangia is uniform. In those in which macrospores are to be produced (oophoridia), one of the parent cells, in no respect different from its fellows in struc- ture, continues to increase in size while they disappear. Its nucleus is soon replaced by four others, which arrange themselves, as in Equisetum, towards the four angles of a regular tetrahedron. Septa are afterwards formed, which divide the cell into four com- partments, in each of which a spore is de- veloped. The spore at first exhibits only a delicate membrane, but as it approaches maturity the three converging ridges, and, finally, the external tegument, the structure of which has been already described, are formed upon its surface. No sooner is this process completed than the membrane of the parent cell disappears, the four spores retaining their relative position, however, to each other, apparently attached by the remainder of the septa. It is at the point at which the spores are in relation with the centre of the mother cells, that the three ridges converge, as well as the three lines by which the valves of the external tegument give way to allow of the growth of the pro- thallium. 95. In those sporangia in which microspores are to be formed, all of the original parent cells exhibit a development which corresponds with that which is above described as occur- ring in one only in the oophoridium, with this exception, that they do not attain the same dimensions. Hence results a large number of microspores which resemble the macrospores in the structure of their internal membrane, and external three-valved tegument, but differ REPRODUCTION, VEGETABLE (VEGETABLE OVUM). completely in their mode of germination. After lying a certain time on a damp surface, their inner cavities are found to be occupied by a number of small spherical cellules, each of which contains in its interior a spirally coiled fibre (antherozoid). By the dehis- cence of the valves of the external tegument, Fig. 179. Vahate dehiscence of microspore of Selaginella hel- ret'ica, six months after sowing, showing escape of antli'irozoids, 300 diam. the antherozoa are set free; and it is presumed, that it is by their agency that the archegonium is fructified, after the prothallium has been laid bare by the bursting of the macrospore at its apex. 96. RhhocarpetB. — In describing the mode of reproduction of the Rhizocarpese, we shall confine our attention to the genus Pilularia, respecting \vhich the most exact researches have been made. 97. The macrospore of Pilularia is an egg- shaped body, presenting an equatorial constric- tion. It consists of an internal proper mem- brane (endospore), the so-called embryo sac, Fig. 180. Section of macrospore of Pilularia some time after germination, 50 diam. a, two layers of the exospore, the outer, vertically striated, the inner, homogeneous; b, cavity of endospore bounded superiorly by the prothallium, the papillaeform summit of which projects through the canal of the exospore. which is surrounded by a white coriaceous exospore. This last exhibits two distinct layers, of which the internal is colourless and vitreous, without trace of structure ; while the external appears to be formed of prismatic columns fitting closely together, which are more distinct at the lower end of the spore, while they disappear entirely towards its smaller end or apex, at which point the exo- spore forms a papilliform projection open at its summit. From this arrangement there results a canal, which is immediately sur- rounded by the thickened and dentate margin of the vitreous layer, and leads to the apex of the endospore. 243 98. The prothallium. — The first indication of the commencement of the germination of the macrospore is the formation of a lenticular accumulation of granular plasma, at the sum- mit of the endospore, which had previously contained only starchy, mucous, or oleaginous granules. Soon after there appears in the same position a delicate cell of similar form, the upper surface of which is in contact with the endosporal membrane, and is iramediately subjacent to the aperture in the exospore. It is in all probability from this cell, although the earlier stages of the development have not been clearly made out, that the prothallium takes its origin. A day or two after germina- tion it consists of a central cell, which is sur- rounded by a single layer of others of smaller dimensions. Four of these last are invariably found interposed between, the upper surface of the large cell and the spore membrane ; the septa by which they are separated being per- pendicular, and at right angles to each other. Soon after the central cell itself divides by a transverse septum into two ; of these the upper, of globular form, contains a large ve- sicular nucleus, the future germ-cell. The lower, which is tabular, divides repeatedly by vertical septa, so as to form a single layer of cells which intervenes between the cavity of the archegonium and that of the spore. In the meantime the four cells which surmount Fig. 18K Vertical section of prothallium of the same at the period of impregnation, which passes through the axial canal of the archegonium, and exposes a, the germ-cell ; b, cavity of macrospore ; b, outer, and c, inner layer of exospore, the apicial canal of which (§ 97.), it completely occupies. the germ-cell extend upwards in the form of four papillae, separated from each other by an axial canal, which burst through the proper spore membrane, and finally project beyond the aperture of the exospore. By the absorp- tion of the central cell, its cavity becomes continuous with that of the vertical quadri- lateral canal above mentioned. 99. The embryo. — In consequence of the presumed entrance of the antherozoids into the cavity of the archegonium, the germ-cell en- larges, and is transformed by repeated division into an embryo, which is at first a somewhat meniscus-shaped body, formed of minute cel- lules. Soon after, a conical projection of its upper surface presents itself, which rapidly R 3 REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 246 increases by the repeated division of a ter- minal cell by alternately inclined septa. The Fig. 182. 77te same after impregnation, 150 diam. The papilla has been broken off in making the preparation. direction of growth of this structure, which is the first leaf of the embryo, is obliquely up- wards. In its axil is formed the primary axis} Fig. 183. of the vertical series of sporangia which cor- responds to each valve, one only of the ori- ginal central cells continues its development, the rest becoming abortive, and finally disap- pearing. The four spores, which are formed just as in Selaginella, at length become free by the absorption of the cell in which they are enclosed, and for a time continue to en- large equally, while their walls are thickened by internal gelatinous deposition. Soon, how- ever, one begins to exceed the rest in growth, and finally occupies the whole cavity of the sporangium, which is subsequently burst by the swelling of the exospore, which is pro- duced when it is subjected to the influence of moisture. 101. The microspores are developed precisely as in Selaginella. The exosporal membrane Fig. 184. Embryo of Pilularia alobulifera, 10 diam. The embryo is still enclosed in the prothallium, the tissue of which has expanded so as to form an investment for it. a, remains of papilla of archegonium with its canal ; b, first root; c, first leaf; d, primary axis; e, cavity of naacrospore. and soon after, as a lateral development from this last, the second leaf. In the meantime the first root makes its appearance as a rounded projection, which grows from the upper sur- face of the embryo, in a direction opposite to that of the first leaf. Both of the last-men- tioned organs finally burst through the remains of the prothallium, and become free. 100. Sporangia and spores. — The organ in which the sporangia of Pilularia are contained is an egg-shaped body, supported on a short, curved pedicle, which springs directly from the creeping stem, in the axil of one of the awl-shaped leaves. It presents a tough, cori- aceous, cellular coat, which encloses a cavity, which is divided into four compartments by vertical septa, and subsequently dehisces in four valves. The middle of the internal sur- face of each valve is, from the first, marked by a ridge of gelatinous cellular tissue, from which the sporangia take their origin as a vertical series of projections. Their development re- mains up to a certain time the same, whether they are to produce large or small spores. All are found to exhibit at this period a central mass of cells, containing nuclei and grumous fluid, which is surrounded by a double capsular layer. In each of the central cells, the nucleus soon after is replaced by four others of smaller size, around which are formed four tetrahedral secondary cells, which are the im- mediate parents of the spores. In the lowest Microspore of the same, 600 diam. The inner membrane projects through the outer, which has given way. A few of the cellules containing spermatozoids have escaped. dehisces in three valves, the proper membrane of the spore at the same time giving way irre- gularly, to allow the escape of numerous little globular cellules. These cellules contain, in addition to starchy and mucous granules, pa- rietal lenticular vesicles, each of which en- closes a delicate, spirally coiled antherozoid, which moves actively in water. 102. Phanerogamia. — Between the higher vascular Cryptogamia, and the simplest forms of flowering plants, there exists, as has been already noticed, a wide chasm of obscurity. The researches, however, of Hofmeister, have shown that in the Coniferas the embryo is formed upon a plan which presents the most striking analogies to what is observed among the Rhizocarpeas and Lycopodiaceas ; and that, in fact, their development stands intermediate between that of the plants just mentioned and the angiospermous Phanerogamia. 103. Phanerogamia gymnospermia. — Follow- ing the same plan of description that we have adopted in the previous section, we shall confine our attention to the Abietinese, of the deve- lopment of which Hofmeister has furnished us with a most complete account. The so-called ovule consists, at the time of the scattering of the pollen, of a short and thick nucleus of delicate cellular tissue, which is enclosed in a single, somewhat fleshy integument, leaving onen a wide micropvle canal.* In the centre open a * For the origin and signification of botanical terms in common use we refer the reader to any of the elementary works on Botany. „ REPRODUCTION, VEGETABLE (VEGETABLE OVUM). of the nucleus there exists an ovoidal embryo- sac, which owes it origin to the coalescence of a vertical and axial series of cells. At this period it contains only granules of starch and Fig. 185. Section of nucleus of ovule of Pinus Austriaca, in the centre of ichich is observed the young embryo- sac, 150 diam. mucus, the nucleus which it at first contained having disappeared. It corresponds, as will he seen as we proceed, to the internal mem- brane of the ripe macrospore of the Rhizocar- peae and Lycopodiaceae. The pollen grain in theConiferaegenerally itself reaches the summit of the nucleus by means of the wide micropyle. From each grain emanates a tube, which pene- trates for a short distance into the tissue of the nucleus; not, however, until it has re- mained for some time upon its summit. In the meantime numerous free nuclei have be- come visible in the embryo-sac, which imme- diately afterwards " presents itself filled with a large number of radially elongated cells, which are arranged in a concentric layer." These continue to multiply by septa in all three directions, until the beginning of winter, at which period the wall of the embryo-sac is so delicate as to be indistinguishable, During the winter months these cells undergo no further change, except that their walls are thickened by internal gelatinous deposition. In the beginning of March of the second year, both the gelatinous material and the cell-wall disappear, the primordial sacs lying free in the cavity of the embryo-sac, each containing a large globular nucleus. Shortly after, the nucleus of each cell disappears, and is re- placed by two or four smaller ones, round each of which new spherical secondary cells are formed. The parent cell is dissolved, snd immediately after, the same process is re- peated in the secondary cells. While this is taking place, the embryo-sac has increased to twenty times its former volume ; its membrane has become resistant and vitreous, while throughout the whole ovule, with the excep- tion of its summit, an active cell growth has taken place. Towards the middle of May the permanent cellular body which after- wards fills the whole embryo-sac, originates by the application, in successive layers, of the 247 cells contained previously in its cavity, to its membrane. By the continuation of this pro- cess, the sac becomes a second time filled with cellular tissue.* Two or three of the cells sub- jacent to the micropyle end of the embryo* Fig. 186. Section of naked ovule of Pinus maritime^ as 06- sei-ved in January of the second year, 150 diam. The spherical embryo-sac is filled with cells, the walls of which are already thickened by gela- tinous deposition. Two pollen grains occupy the funnel-shaped space between the wide micropvle and the summit of the nucleus. The cellular tissue of the latter is penetrated by two tubes emanating from the pollen grains. At the dotted line the tissue of the ovule becomes continuous with that of the spermophore. sac now become larger than the rest, and are destined to contain the germs of the future embryos. As their development proceeds, these bodies, the so-called corpuscula, assume an elongated, oval form, and the space in- tervening between their summits and the membrane of the embryo-sac is occupied by four small cells on the same level, which ar'e Fig. 187. Four cells which surmount the corpusculum of Pinus sylvestris, seen from above, 200 diam. * To this tissue is commonly applied the term albuminous body." It corresponds in its mode of rierin with the " endosperm " ( § 106.") of other origin with the Phanerogamia endosperm" (§ 106.) R 4 REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 248 separated from each other by as many vertical septa, meeting at right angles. Each corpus- culum is likewise surrounded on all sides by a single layer of cellules resembling pavement epithelium, and exhibits in its interior a nu- cleus which is usually placed at its superior extremity. After some time the nucleus dis- appears, and now a number of transparent vesicles become visible, which accumulate for the most part towards the extremities of the corpusculum, Fig. 188. Corpusculum of tlie same in section, immediately be- fore impregnation, 200 diam. Its cavity is filled with transparent vesicles, and bounded superiorly by four granular cells, the position and relations of which recal very forcibly the arrangement which presents itself in the rudimentary archegonium among the higher Cryptogamia. 104. The growth of the pollen tube, which has been for many months arrested, at last re- commences ; the membrane of the summit of the embryo-sac at the same time becomes attenuated, and immediately after is pene- trated by the narrowed end of the pollen tube, which is brought into immediate con- tact with the summit of the corpusculum, the four cells which previously surmounted it having disappeared. At this time, the corpus- culum exhibits in its interior, at the end oppo- site the pollen tube, a single vesicle, much larger than those by which it is surrounded, within which is afterwards developed a se- condary cell, occupying more than half its cavity. This cell, which is convex above, is applied by a flattened inferior surface against the wall of the corpusculum. It soon divides by a longitudinal septum into two, each of which is nucleated. These two cells, which occur throughout the Coniferae, form the commencement of the suspensor. They next divide by a second pair of vertical septa, at right angles to the first; and in each of the four cells which result, a succession of hori- zontal septa are formed, by which they are converted into four vertical columns inti- mately united to each other. The suspensor lengthens in one direction only, partly by the repeated division of the four inferior terminal cells, partly by the interstitial growth of those first formed. Soon it bursts through the Fig. 189. Corpusculum of the same, 120 diam. The four cells by which it is bounded superiorly have disappeared. The pollen tube is still in contactj by "its flattened extremity with the corpusculum, and by the rest of its surface with the cells of the albuminous body, a, 300 diam. Earlier stage of development of lower end of the same. A single germ-cell is applied to its wall. b, 300 diam. Division of germ-cell into four by two vertical septa, of which one only can be seeu on section, c and d, 250 diam. Division of the four resulting cells by a succession of transverse septa. Above d are two of the numerous com- plexes of cells, which at this time float in num- bers in the corpusculum. (From fig. 172 to 189 inclusive, are after Hofmeister). membrane of the corpusculum at its lower end, and becomes immersed in the tissue which occupies the embryo sac, the cells of which, at the same time, become less intimately united than before. The four series of cells of which the suspensor is formed, now separate, and, from the terminal cell of each, the rudi- ment of an embryo takes its origin. Its development commences, like that of the embryos of theHepaticae and of the first leaves of the Ferns and Equisetacese, by the repeated formation of alternately inclined septa in a terminal cell ; these being followed by vertical septa radiating from the axis, and, subse- quently by others parallel to the external surface. Of the four embryos thus formed, one only advances to vigorous maturity. 105. Phancrogamia angiospermia. — The ob- servations on record relating to the origin and development of the embryo among these plants are now so numerous, that although the conditions are much more complicated, and the difficulties in themselves much greater, we are, notwithstanding, more competent to draw our conclusions with confidence than we have found ourselves to be in our previous study of the Cryptogamia. Among the many examples at our disposal, we select two of the simplest, between which, at the same time, great differences present themselves in those respects in which the development is variable. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 106. Hippuris vulgaris.* — The already ana- tropous ovule of this plant consists of a cylin- drical nucleus of delicate cellular tissue, along one side of which is observed a longitudinal fleshy ridge, terminating above in a short funi- culus, by which the ovule is suspended from the apex of the one-celled ovary. One of the central cells of this nucleus becomes larger Fig. 190. 249 into a tubular superior, and a spheroidal and much smaller inferior compartment. The Section of naked nucleus of Hippuris vulgaris at an early stage, about 16U diam. The embryo-sac is seen as a large central nucleated cell. (Unger.) than the rest, from which it is further distin- guished by its containing a free vesicular nu- cleolated cell-nucleus and granular fluid. This cell, the embryo sac, rapidly enlarges, and at the same time assumes an elongated oval form. A number of vesicles of various size are de- veloped at the same time, at its micropyle extremity, all of which disappear some time before the scattering of the pollen. Shortly after this has taken place several new cells are formed, one of which, situated towards the upper end of the sac, begins at once to lengthen, and is finally converted into a tube closed at both extremities (germ-cell). The rest arrange themselves in vertical series, so as to form a continuous tissue (the endo- sperm), which completely occupies the lower part of the sac. After this, in consequence, as may be presumed, of the contact of the pollen tube with the membrane of the sac, the germ-cell is divided by a transverse septum * Unger, Botanische Beobachtungen, Entwick. des Embryos von Hippuris vulgaris. Bot. Zeitung, 1849, p. 329. Sanderson, On the Embryogeny of Hippuris vulgaris. Trans, of Bot. Soc. of Edinburgh, Feb. 1850. Upper end of embryo-sac of the same as observed immediately before impregnation, 250 diam. The tubular germ-cell, the lower end of which is embedded in the nucleated cells of the endosperm, occupies its axis. latter, which is the parent cell of the embryo, is divided by a vertical septum into two hemispheres. In these two new septa are formed, also vertical, but at right angles to The same immediately after impregnation. The germ-cell is now divided by a transverse sep- tum into two compartments, the inferior of which is the parent-cell of the embryo. 250 diam. the last. In the meantime, several new vesioles make their appearance in the upper tubular compartment of the germ-cell, which eventually become cylindrical, and arrange themselves, end to end, in its interior. The four cells of the embryo now divide by hori- zontal septa, which are succeeded by others parallel to its surface, and meeting their pre- decessors at angles of 45°. The globular body which is thus formed, consists of six- 250 teen cells, of which eight are superficial, and the other eight enclosed as a central spheri- Fig. 193. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). Annals of Natural History : — " The ovule springs from the placental surface as a single projecting cell, which, by subdivision, soon becomes a cellular papilla (the nucleus), com- posed of a central cell (the embryo-sac), sur- rounded by a simple cellular layer. The two coats gradually grow up over this, and by the greater elongation of one side the ovule becomes anatropous. The nucleus mean- while loses its cellular coat, apparently by absorption, and appears as a large oval sac enclosed in the coats, consisting in fact merely Fig. 195. Later stage. Division of parent-cell of embryo by a vertical septum. The vesicles contained in the upper tubular por- tion of the germ-cell have now arranged them- selves so as to form a filamentous prolongation to the embryo, about 200 diam. cal mass. By the frequent repetition of the same process it increases in size, still retaining Fig 194. Isolated sixtcen-ceUed embryo of the same, with its filamentous prolongation, about 150 diam. its globular form, until it is transformed into an embryo, the direction of growth of the axis of which is downwards. 107, Orchis Morio. — In the Orchideae the structure of the ovule is remarkably simple. The following description of the mode of origin and early development of the embryo, in Orchis Morio, all the stages of which we have ourselves followed, is taken from Mr. Hen- frey's paper on Vegetable Reproduction, in the Early condition of ovule of Orchis mascula. The embryo-sac is exposed in consequence of the absorption of the cells which previously sur- rounded it, 180 diam. of an embryo sac. In the apex of this, about the epoch when the pollen falls upon the stigma, three cellules (embryonal vesicles), make their appearance at the upper end of Fig. 196. Isolated embryo-sac of the same immediately before impregnation, containing three embryonal vesicles, 180 diam. the embryo sac, formed apparently by free cell-formation around a globule of protoplasm. The pollen masses on the stigma send down pollen tubes, which traverse the conducting tissue of the style, and make their way to the placentas, where they enter, ordinarily, singly (sometimes more than one) into the micro- pyle canals of the ovules, and come in contact with the outside of the apex of the embryo sac, immediately above where the embryonal vesicles lie ; but the pollen tube does not pene- trate the embryo sac. Soon after the pollen tube has reached the embryo sac, one (very rarely two) of the embryonal vesicles begins to swell, becomes divided by a cross septum into two cells, and while the upper one grows out in a filamentous form through the micropyle, by a continued process of cell-division, the lower cell enlarges, and divides repeatedly so as to form a cellular globule — the embryo, which in this plant does not go on to produce a co- tyledon and radicle, as in most other cases. The filamentous prolongation, the use of REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 251 which is not evident, but which seems ana- By continuous cell multiplication an organ logous to the suspensor, presently to be is formed, in which may be distinguished a mentioned, meanwhile decays away."* Fig. 199. Fig. 197. Ovule of the same at the period of impregnation, x, the external integument ; c, the internal, which immediately surrounds e, the embryo-sac. The pollen tube p, after passing the wide exostome becomes sensibly narrowed as it penetrates the canal leading to the embryo-sac, with the out- side of which its termination is in contact. 180 diam. 108. The anther and the pollen cell. — The history of the development of the anther is remarkably uniform among the different families Fig. 198. The same, some time afler impregnation. The remains of the pollen tube are observed to be still adherent to the sac. The rudiment of the embryo exhibits itself as a somewhat pear-shaped cell, divided towards its upper part by a succes- sion of transverse septa, into numerous compart- ments. The lowest of these, larger and more granular than the rest, is the parent-cell of the embryo. 180 diam. (The above, from 191 to 198 inclusive, are original.) of Phanerogamia. It at first appears in the young flower-bud as a cellular papilla, which grows out laterally from the floral axis. * Henfrey, On the Reproduction of the higher Cryptogamfa, and the Phanerogamia. Annals of Nat. Hist., June, 1852. Further developed embryo. (Orchis Morio.") The embryo-sac is no longer distinguishable. The spheroidal embryo which completely occupies the cavity of the ovule is surmounted by a fila- mentous prolongation, which projects through the micropyle. 150 diam. (Henfrey.) central cylindrical column (connective), along the antero-lateral aspects of which are at- tached two larger cellular masses; the outer surface of each is marked by a vertical furrow, indicating its division into two halves, which are the rudiments of the future facuti. In each half a single axile vertical column of cells soon becomes distinguished from those surrounding them by their greater size and granular contents. In each of these cells the nucleus disappears, and is replaced by two others, this being followed by a division of the cell contents (primordial membrane), which results in the formation of a new cell round each nucleus. By the repeti- tion of this process a mass of cells — the parent-cells of the spores — is formed, which occupies the centre of each rudimentary loculus. The next change observed is the thickening of the walls of the parent-cells by gelatinous deposition on the interior surfaces. This is followed in all of them by disappear- ance of the nucleus, and consequent division of the contents of the cell (primordial mem- brane) into two portions, each surrounding a new nucleus. These, however, are only trans- itory formations, and are soon succeeded by four permanent nuclei, which are placed towards the four angles of a regular tetrahe- dron, each invested with a primordial sac con- taining a granular mucus, on the surface of which is soon secreted a gelatinous layer. In this manner the parent cell is divided into four compartments — the so-called special parent cells of the pollen grains. Within each com- partment is now formed a new cellulose mem- brane on the surface of the primordial utricle. This is transformed into a resistant and co- loured tegument, which is the outer mem- brane of the pollen grain, and exhibits various projections of its surface, which differ ac- cording to the species. 109. While these changes are taking place in the central mass of each loculus, the tissue forming its wall is transformed into a capsule of three distinct cellular lavers. Tiie inner REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 252 layer consists of radiating prismatic cells, and is soon absorbed. The cells of the second layer are distinguished by their containing at first numerous starch granules, and afterwards by the deposition of spiral fibres on the inner surfaces of their walls. These are usually dice-shaped cells arranged in concentric layers. The external or epidermic layer consists of tabular cells in contact by their edges.* 110. Review of the analogies which present themselves in the history of the development of the reproductive organs of the higher Cryptogamia and of the Phanerogamia. — The families in question are distinguished by the presence of what is called "sexual reproduction" from all others. It is true that among the Characeae, Conju- gates, Vaucheriaceae, and Desmidese, the con- currence of two dissimilar parts is necessary for the development of the germ ; but in them the phenomena do not present themselves in such strict conformity to law, and the anato- mical relations of the germ to the organ which contains it are not nearly so complicated as in the plants under our consideration. Taking the sexual germ as our starting point, in com- paring the history of the development of the phanerogamous with that of the cryptogamous plant, the following analogies present them- selves : — 1 1 1. — 1. Analogies existing between the ovule, the anther, and the sporangium — In Zostera marina the termination of a stem destined to bear reproductive organs, is broadened out in the form of a spatula, concave on one side, convex on the other. On the concave sur- face are observed, early in the development, two vertical series of papillae — one on each side of the middle line — which are the rudi- ments of the organs which support the ovules and anthers. In each series, the two kinds of rudiments are arranged alternately in such a manner, that an ovule in one series is always on the same level with an anther in the other. The rudimentary organ which is destined to contain the ovule, commences as an imperfect ring of cellular tissue, on the inside of which is seen a little round projection — a bud in the axil of a leaf. From this projection is developed the ovule, with its teguments, just as described in Orchis Morio. The axis of its nucleus is occupied by a vertical series of cells. Of these the uppermost enlarges, and becomes detached from its neighbours, so as to form the embryo-sac.-)- If we compare this process with what occurs in Selaginella, we find in each case, a cell belonging to the stem in the axil of a modified leaf, which transforms itself into an axial organ. In each case one of the central cells enlarges and becomes detached — in Selaginella, to form the mother * NSgeli, Zur Entwick. des Pollens, &c. Zurich, 1842 ; Wimmel, Zur Entwick. des Pollens, &c. Bot. Zeit. 1850, S. 225. f Hofmeister, Entwick. der Zostera. Bot, Zeit. 1851; Grb'nland, Beitrag. zur Kennt. der Zostera marina, &c. Bot. Zeitung, St. 10. 1851. cell of four spores — in the phanerogamous plant, to become the embryo-sac. 1 12. The exact correspondence, step for step, which exists between the development of the anther, and that of the sporangium, will be best seen by successively comparing the de- scriptions contained in § 89 and § 108. It is rendered still more striking when we consider the very remarkable variations which present themselves in the structure of the anther among the Phanerogamia themselves ; as e. g. in Zostera, among the Orchidaceae, and other examples for the description of which space is wanting. The contemplation of these analo- gies leads us to remark how little relation there seems to be as respects the organs under con- sideration between the morphological import of the rudiment and its development. The ovule of Zostera is an axial organ, originating in the axil of a modified leaf; its analogue in development, the anther, is itself a bilateral foliar organ. The sporangium of Equisetuin seems to originate as a leaf, — that of Selagi- nella, as an axis in the axil of a leaf. 1 13. — 2. Analogy between the embryo-sac y the pollen cell, and the parent cell of four spores — In approaching this, the most difficult part of our inquiry, we must refer to the Coniferae, as holding in so many respects an intermediate position. Of those stages of the development which precede the act of impregnation in Se- laginella, the first, namely, the division of the parent cell into four compartments, and the formation of a spore in each, is entirely wanting in the Coniferae. The prothallium — under- standing by the term the organ of which the archegonia form a part — is represented by the corpuscula, between which and the archegonia, the resemblance in structure is very striking. — The difference in the mode of origin of the germ-cell, on the other hand, is no less re- markable. "Among the Cryptogamia there is," says Hofmeister, "only one germ-cell which completely fills the central cell of the arche- gonium, while in the Coniferae, very numerous germ-cells swim in the central cell of the cor- pusculum, of which one only, applied against its lower end, is fecundated." In the gymno- spermous Phanerogamia, all the steps of de- velopment which intervene between the parent cell and the germ, disappear; the latter origi- nating altogether independently at the upper end of the embryo-sac. As the transforma- tion of the germ-cell is the most important element in the process of development, it presents the greatest degree of constancy. It always commences by the formation of one or more septa, the direction of which, in rela- tion to that of the first axis of growth, is transverse or nearly so. 114. In the Hepaticae and Mosses one sep- tum is formed, the inferior of the two result- ing cells undergoing no further development, while the superior is transformed into the pri- mary axis of the fruit. This fruit-axis, the apex of which is converted into a sporangium, is normally a leafless one. In the Mosses, how- REPRODUCTION, VEGETABLE (VEGETABLE OVLM). ever, examples frequently occur, in which its development is changed, under the influence of peculiar external circumstances, in such a manner that, instead of producing a sporan- gium it lengthens considerably, and bears symmetrically arranged leaves. Such a con- dition makes" it more easy to compare the fruit of the Mosses and the leafy stems of the higher plants. In the Ferns and Equisetaceae, again, only one transverse septum is formed; but here, it is the inferior secondary cell which is developed to the embryo, the direction of the first axis of growth being opposite to that of the archegonium. In Selaginella, a succession of transverse septa are formed, whence results a conferva-like fila- ment, which lengthens downwards by repeated division of a terminal cell. At length the youngest cell is transformed into an embryo. Among the Coniferae, the same process pre- sents itself, with this important difference, that before it commences, the germ divides by two crucial vertical septa into four cells, which correspond to the four embryos which are afterwards formed. In all the Phanerogamia, probably without exception, the germ-cell divides," in the first instance, by a trans- verse septum into two cells, of which the upper is the larger. In some cases the lower cell is developed directly to a spherical cel- lular mass (as in Hippuris and Orchis Morio). Much more frequently, however, it is trans- formed into a conferva-like filament (sus- pensor) which lengthens by repeated division of an inferior terminal cell. At length the youngest cell, instead of lengthening, becomes spherical, and gives rise to the embryo by a process similar to that described above in Hippuris. 1 15. The organ to which the name suspen- sor is applied by Mr. Henfrey in Orchis Morio, differs materially from that of Selaginella, the Coniferse, or from that described in the pre- ceding paragraph. Its formation does not, like that of the true suspensor, precede, but follows the origin of the embryo. In Hippuris, it appears to result from endogenous cell-forma- tion in the lengthened upper compartment of the original germ-cell. 116. The difference bet ween the development of the pollen grain, and that of the microspore of Selaginella and of the Rhizocarpeae, is no less remarkable. Among the Phanerogamia, after the pollen grain has remained for some time in contact with the stigma, its inner mem- brane grows out at one point of its periphery into a filiform cell ; this lengthens more or less rapidly until it reaches the micropyle of the ovule, which it enters, and at last comes into contact with the embryo sac. The sac usually resists it strongly ; sometimes it is bulged in, but is very rarely perforated. In consequence of this act the transformation of the germ-cell commences. The absence of moving filaments among the higher plants stands connected with the intervention of a second membrane (that of the embryo sac) between the two fluids, the union of which ! 253 seems to constitute the essential condition of fecundation. 117. In comparing the development of the microspore with that of the spore of the Ferns with which the plants among which it presents itself are so closely allied, the difference is even more striking. In Selaginella all the steps intervening in the Fern between the spore and the tessellar cells of the antheri- dium have disappeared. 1 18. Direct observations relating to the act of impregnation among the Cryptogamia, are for the most part wanting. The presence of antherozoids in the cavities of the archegonia of the Ferns has been witnessed only by Su- minski and Mercklin. Among the Hepaticae and Mosses, Hofmeister observed within the involucre of Jungennannia bivaricata,anthero- zoa " which moved rapidly and played livelily round the archegonia."* In this species, as well as in J. bicrenata and bicuspidata, the same observer found a mucous substance of glass-like transparency, occupying the mouths of the archegonia. In this substance were embedded numerous curled fibres, which he considered to be dead antherozoids. Evi- dence more to be depended upon is that of the concurrent testimony of all observers that, among the dioecious mosses and liver- worts, wherever plants bearing archegonia grow in the neighbourhood of those bearing antheridia, fruits are almost always produced ; while in the contrary case, the archegonia are abortive. 119. Origin and development of germ-cells in special organs destined for their reception, which are capable of transformation into rudiments of new plants, without the concurrence of two organs of opposite functions. — Of this, distinct ex- amples occur only among the Hepaticae ; viz. among the leafy Jungermanniae, and the Marchantiae. In one of the latter, the Lumtlaria vulgaris, there is formed by the doubling in of the epidermal layer of the upper surface of the frond, immediately behind the notch in the anterior margin, a crescentic pouch, which extends backwards for about a line under the surface. Its cavity is bounded by an inferior and a superior wall, whose concave surfaces unite in a sharp margin, the plane of which inclines slightly backwards and downwards. The upper wall is formed by the double epi- dermal membrane ; the lower by a membrane which is intimately united with the parenchyma of the frond, in its relations to which it re- sembles the tissue which lines the subepider- mal air cavities. It consists originally of a single layer of tessellar cells, much smaller than those upon which they are supported. A number of these grow out into papilliform projections, in each of which the projecting hemispherical portion is soon separated by a transverse septum. A second is then formed above the first, and parallel to it. The highest cell next divides by a vertical septum parallel * Hofmeister, Yergleichende Untersuchungen, &c. S. 38. Vide supra, Fig. 164. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). face grow out into nipple-shaped projections, which soon become filamentous roots, and the whole is transformed intoa riband-shaped frond. The organ, the development of which is de- 254 to the axis of the frond. This is followed on each side by transverse, and afterwards by Fig. 200. Vertical section of floor of gem-pouch of Lunularia, 50 diam. The club-shaped rudiments of the gems are attached by their bases to the superficial layer of cells, which are much smaller than those upon which they are supported. vertical septa, which last are parallel to it. Hence results a bilateral organ, the surfaces of Fig. 201. Mode of origin of the gem. Two of the cells of the superficial layer are seen more highly magnified. The membrane of each has grown out into a nipple ; in one the vertical septum can be distinguished. 400 diam. which are at right angles to the axis of the frond. Its form is at first that of a flattened Fig. 202. a flattened rudiment of the gem viewed laterally. Division of the second cell of the rudiment by a vertical septum, on each side of which the com- mencements of several transverse septa are mo- delled out in the protoplasma. 400 diam. 6, the same at a later stage, 250 diam. club : afterwards, as it becomes larger, two notches are formed on each of its lateral margins, which exactly resemble those of the anterior margin of the young frond. As soon as its development is completed — that is, when it has attained a length of about £ of a line, it is pushed out of the receptacle by its rapidly growing successors. If, after its expulsion, it is sown on a damp surface, a new growth at once commences in two opposite directions, in a line which is at right angles to its axis. At the same time the cells of the inferior sur- Fig. 203. Outline of gem as observed two or three days after it has bean sown, 50 diam. In its inferior margin is a notch which indicates its point of attachment to the floor of the gem- pouch. The other two notches, one on each side, are the points of growth of the young plant into which the gem is transformed : they resemble those which are described (§ 58.) in the margins of the young frond of Anthoceros. It is remark- able that the line of direction of growth of the young plant is at right angles both to that of the gem itself, and to that of the parent plant. scribed above, receives, in common with others of a different nature, the name of " gem." The whole process differs widely from that of true gemmation or " rejuvenescence " of an old cell, in order that its primordial vesicle may be transformed into an embryo. This distinction is well illustrated in the gemmation of Anthoceros ; the primordial sac of a cell of the parenchyma of the frond, the position of which is undetermined, contracts and secretes on its surface a new cellulose membrane. The new cell is converted by repeated division into the rudiment of a young frond, which, as it grows, breaks through the tissue of the parent. In Jungermannia bivaricata, we have observed a similar process. A single cell of the leaf of a marcescent, last year's stem, is seen still to contain a primordial vesicle, lined with green protoplasm. This forms around itself a new cell, which divides by a septum, the direc- tion of which is transverse in relation to that of the first growth. One of the resulting cells grows out so as to project through, or carry before it, the membrane of the old cell. This divides by a septum inclined obliquely to the former, which is succeeded by another, inclined in the opposite direction, and so on alternately. Hence results the rudimentary stem of a new plant. Both of the preceding are examples of gemmation. The very distinct analogies in development (homologies) which present themselves among the higher plants, are exhibited in the following table. The six last vertical columns represent the principal groups, which follow each other in the same order as in the preceding pages. In the two first columns are indicated those more partial analogies which may be traced between the higher plants, on the one hand, and the Algae, Fungi, and Lichens on the other. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 255 kw Him 1! i I x 3 53 "5 £5= ii ii Hi a1? s iiii i iilli lifl! ! !.= ;•= :l^ Hill lifli !«iil II H III fflHK-fKI.I.. irmlnation rc.uit inulfon of a LI. m I. Ml, III. I. ondow? or leafy tli.Tidnim. therozoidt. chenonlum. l§ 1| II ii :li F I ill i u •r tin 1 1? * 1 1 , ^ -; I I I " £ £ 5 S S 111" I He. •«.i.i;u-lc Mil Cli.ir.i. - 4 • g 1 1 * j J M ^5*3 Js I !l! Hill REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 256 APPENDIX. — On the relations which exist between the animal and vegetable kingdoms, as regards the function of reproduction. In the introduction to the foregoing article, it was observed that, if any analogies in deve- lopment may be supposed to exist between plants and animals, they are to be sought be- tween the lowest members of the two series. Whether we conclude that it is or is not pos- 'sible to mark out the limit which separates the one kingdom from the other, it is not to be overlooked that the phenomena of reproduc- tion, and consequently the whole circle of the development, of the zoosporous Algae resem- ble more those which present themselves on the other side of the disputed territory, than those which occur among the higher plants. Let us compare the development of a unicel- lular Alga, with that of one of the simplest Infusoria. An egg-shaped body composed of a homogeneous and contractile substance — as regards its chemical constitution nitroge- nous—displays active motions, and exhibits two locomotive organs springing from its smaller end. Soon, however, its motions be- come languid ; a newly formed cellulose mem- brane, which is not contractile, encloses it, and now it undergoes a kind of cleavage, which results in the formation of a number of new bodies. In each of these, as soon as they escape from the parent, the same transforma- tion is repeated. In the other case, taking the development of Vorticella as an illustration (in the de- scription of which we follow Stein*), we find that a disc-shaped mass of homogeneous con- tractile substance (a monad), is transformed into a stalked and ciliated Vorticella. After having been for a time endowed with ac- tive motion, and with a power of ingesting food, the Vorticella enters into a state of re- pose, and at the same time is enclosed in a flexible membrane or cyst. ' The interior of the cyst is now occupied by a mass of proto- plasma, which is no longer contractile, and presents no trace of the structure of the former Vorticella. By a process similar to that which occurs in the plant, this plasma divides into a number of disc-shaped bodies, resembling that from which the parent origi- nated. Between the Protozoon and the Protophy- ton, there is an intermediate group, of which the Euglena viridis, alluded to in § 1 ., may be considered as the representative. The Eu- glena after actively moving for a time, enters into the condition of repose, becoming at the same time enclosed in a new membrane. What follows this change, however, has not been as yet ascertained. * Stein, Wiegmann's Archiv. fur Naturgesch. 1849. Bd. i. p. 92. The phenomenon of conjugation, also, while it is without parallel among the higher plants, presents itself under nearly similar conditions among the Infusoria. According to the ob- servations of Stein, the circle of changes described in the preceding paragraph, is not the only one by which in Vorticella the spe- cific form is reproduced. A Vorticella enters into a state of rest, and becomes encysted ; it is not now, however, converted into a mass of homogeneous protoplasma as in the former case. The cyst membrane changes into a thin walled vesicle, while from the body of the enclosed Vorticella, which has assumed a spherical form, there emanate a number of contractile radiating processes. It is now a Protozoon, identical with that to which has been given the name Actinophrys. Now in Actinophrys, the occurrence of conjugation has been recorded by several trustworthy observers. It was first described by Kol- liker*, afterwards by Sieboldf, and finally by Colin. J According to the last-mentioned author, two neighbouring individuals after approaching more and more closely to each other, emit from their opposite surfaces, vesi- cular processes, which finally unite. As the union becomes more complete, the two seem to form but a single animal. As to what are the results of this remarkable conjugation, neither Colin, nor, as far as we know, any other observer, is able as yet to speak posi- tively. Every fully formed Actinophrys ex- hibits embedded in its substance a central nucleus-like body ; this nucleus, according to Stein, is sooner or later transformed into an egg-shaped animal, which grows at the expense of the parent, and finally becomes endowed with active motion. At the smaller end is formed a crown of cilia, at the larger an oral depression, and soon there presents itself a perfect Vorticella. It is, at least, extremely probable that this development is the result of the previous conjugation of two Actino- phries. The analogies which have been under our consideration in the preceding paragraphs, may be placed in a clearer point of view, by exhibiting them in a tabular form. Referring the reader to the description contained in $18. of the most simple form of unicellular conjugating Algae (Palmogloea macrococca), we shall contrast the circle of development, as it presents itself in Palmoglcea and Proto- coccus on the one hand, with that of Vorti- cella on the other, as follows : — * Das Sonnenthierchen. Zeitschrift fur Wiss. Zool. i. p. 198. f Ueber die Conjugation des Diplozoon para- doxum, u. s. w. foe. cit.iii. p. 62. 1851. | Beitrage zur Entwick. der Infusorien, I. c. iv. p. 252. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 257 Zoosporous Unicellular Alga. Conjugating Unicellular Alga. Protozoon.* Production of a series of Zoospores. Cessation of motion. Production of a series of sterile Podophryce. \ Conjugation of two Podophryse. Cessation of growth. Production of a series Monads, which are transformed into Vor- ticellw. Cessation of motion. Transformation'of Vorticellae into sexual Actinophries. Conjugation followed by Cessation of growth. * In the zoosporous Algae, constantly recurring series of unisexual generations are produced indefinitely. In Vorticella the production of Monads may also recur repeatedly, without the intervention of any sexual stage. So long as this is the case the two developments correspond completely. Here it may be observed that in the stage of cessation of growth, which, in the Pro- tozoon, as well as in the Protophyton, follows the act of conjugation, we have a condition which corresponds to that of the ovum of the higher animals. The ovum after passing through a period of repose, resembling that which presents itself in Podophrya, exhibits a series of transformations, which correspond to the later steps of the developments under our consideration. This correspondence is, as might be expected, more distinctly seen in the lower than in the higher animals. Thus for example, in the development of a Trema- tode Worm (Distomum pacificum), the mass of the yolk is transformed into a locomo- tive rudiment resembling an infusory animal. Within this originates an asexual, but fertile nurse, the homologue of the Vorticella, in the interior of which is formed a second and numerous generation of animals endowed with locomotion (Cercariae). In these, after a time, the locomotive power is lost, and each finally becomes a sexual Distomum.* Although the foregoing homologies are founded on observations the details of which are as yet imperfectly worked out (on which account it may seem somewhat premature to draw attention to them), they are not open to the objections which may be urged to homo- logies supposed to exist between the highest members of the two series. There, the con- necting links are wanting; here, we pass through closely related intermediate forms, from the Alga to the Protozoon, and from the Protozoon to the Trematode Worm. Hence, while we are not justified in applying the term ovum to the generative product of the phanerogamous plant, the present state of our knowledge allows us with propriety to compare with the ovum the result of con- jugation as it occurs among the Algae. The differences in chemical composition which exist between the Algae and the Pro- tozoa will not serve as a ground of distinc- tion. Euglena is invested during its period of repose with a cellulose membrane and contains granules of chlorophylle. In Poly- toma uvella we find, on the one hand, the contractile vesicles of the infusory animal, on the other, starch in the granular form, so characteristic of the plant-t (J. Bur don Sanderson.) * Cams, " System der Thierischen Morph.," s. 329. t A. Schneider, "Beitrage zur Entwick. der In- Supp. BIBLIOGRAPHY. — ALCLE. — Kohlreuter, Das en- deckte Geheimniss der Cryptogamie. Carlsruhe, 1777. Hedwig, Theoria Generationis et Fructifica- tionis Plant. Crypt. Leipsic, 1798. Voucher, His- toire des Conferves d'Eau douce. Geneva, 1803. Kaulfu&s, Die Keimung der Characeen. Leipsic, 1825. Unger, Die Pflanze im Momente der Thier- werdung. Vienna, 1843. Miiller (.£), Entwick. der Chara, Bot. Zeit., 1845, p. 410. Balfs, British Desmidiae. London, 1848. Kiitzing, Phycologia generalis. Nordhausen, 1845. FUNGI AND LICHENS. — Malpighi, De Plantia quae in aliis vegetant, Op. omn. i. i. 48. Meyen, Pflanzen-Physiologie, v. iii. Meyer, Entwick. der Flechten. Gottingen, 1825. Wallroth, Natur- gesch. der Flechten. Frankfurt, 1825. Unger, Die Exantheme der Pflanzen. Vienna, 1838. Korber, De Gonidiis Lichenum. Berlin, 1839. Schmitz, Bei- trage zur Anatomie und Physiologic der SchwSmme. Linnaea, 1843. HEPATICJE AND MOSSES. — Schmidel, Icones Plantarum, 1762. Hedwig, Fundamenta Hist. Nat. Muse. Frond. Leipsic, 1782. Nees v. Esenbeck, Naturgesch. der Europ. Lebermoose, 1838. Bi- scAo/f and Lindenberg, Nova Acta A. L. C., xvii. and xviii. Mohl, Anatom. Untersuch iiber Sphagnum, Sporangien der mit Gefassen versehenen Ciyptog. Tubingen, 1837. Schimper, Recherches sur les Mousses. Strasbourg, 1848. Lanzius Beninga, De Evol. Sporidiorum. Gottingen, 1844. FERNS AND EQUISETACEJE. — Agardh, and Vau- cher, Mem. du Mus. d'Hist. Nat. de GeneVe, 1822- 23. Kaulfuss, Das Wesen der Farnnkrauter. Leip- sic, 1827. Moht, Morphol. Betrachtuagen iiber die Cryptog., Tubingen, 1837. Bischoff, Entwick. der Equisetaceen, Nova Acta A. L. C., xiv., 1828. Ndgeli, Anther, der Farnnkrauter, Zeit. f. w. Bot,, i. 168. Zurich, 1844. Leszczyc Suminski, Ent- wick. der Farnnkrauter. Berlin, 1848. Merkltn, Prothal. der Farnnkrauter. St. Petersburg, 1850. RHIZOCARPEJE AND LYCOPODIACE^E. — Bischoff, in op. cit. N'dgeli, in op. cit., extr. in Ann. des Sc. Nat., ix. 99. MUJde, Entwick. der Equiseten und Khizocarpeen, Nova Acta A. L. C., 1852. PHANEROGAAIIA. — Camerarius, Dissertatio de re Botanica, 1676. 4to. Tubingaj, 1717. Grew, Anat. of Vegetables, &c., 8vo. London, 1672. Malpighi, Anatome Plantarum. Op. omnia, t. ii., fol. Lon- don, 1687. LinruKus, On the Sexes of Plants. Lon- don, 1786. Morland ( Samuel}, Observations on the Parts and Use of the Flower and Plant, Phil. Trans., 1703, p. 1477. Treviranus, Die Entwick. des Em- bryo. Berlin, 1815. Amid, Mem. della Soc. Ital., xix., pp. 253-257. Padua, 1823. Brown (Kobt.), Bo- tanical Appendix to King's Voyage. London, 1826. Fritsche, Devel. du Pollen, Mem. de 1'Acad. de St. Petersbourg, 1835. Schacht, Entwickelungsges- chichte des Pflanzen-Embryo. Amsterdam, 1850. The reader is further referred to various researches contained in the 3rd Series of the Ann. des Sc. Nat. fusorien," Mtiller's Archiv. No. 2. 1854. These re- searches we recommend to the reader's attention, as containing observations of great importance in relation to the present question. 258 RESPIRATION, ORGANS OF. RESPIRATION.— ORGANS OF. I. Hu- man and Mammalian.— The respiratory system of organs in man and mammalia comprehends the larynx, the trachea, and the lungs : embry- ologically, the thyroid and thymus glands should be included in this category. The em- bryonic apparatus of the branchial arches falls under the same denomination. In this article the trachea, bronchi and lungs only will be studied, in their general and minute anatomy. These parts in the human subject will be described at length. In mammalia the pro- minent varieties of structure occurring in some of the commoner genera will be incidentally noticed. THE LUNGS (wc^/fa?, Gr. ; Pulmo, Lat. ; Poumon,T?r.;Lungen, Germ. ; Lungs or Lights, Engl.) coincide typically in structure with the compound grape-like glands. The lobules and air-cells constitute the glandular paren- chyma. The larynx, trachea and bronchi represent the excretory apparatus. They differ from all other glands, however, in the mechanism of their action. They simultane- ously eliminate and absorb. In the lungs two diametrically opposed functions proceed in the same place at the same time. This mechanical paradox occurs in the example of no other gland. Secretion and excretion are successive steps of the same process. They are not contrary functions. The whole mass of the blood passes through the lungs : other glands receive only a part. The air-passages and cells are far more capacious than the corresponding parts of other glands. This characteristic results from the aeriform nature of the compounds emitted and received. Aeriform bodies are subject to rapid varia- tions of bulk ; fluids undergo no material changes of volume, through fluctuations of temperature ; thence, in the instance of the lungs, results the necessity for mechanical pro- visions, which in ordinary glands would exist to no purpose. The elastic tissue and resilient cartilages so abundantly introduced into the structure of the air-passages and cells realise the required provision. The excretory ducts of all other glands are membranous, the opposite sides of which are capable of collapsing into contact. Fluid in motion readily forces its way through a collapsed tube : air can only traverse a patulous channel. In man the lungs are two in number. They are contained in the cavity of the thorax, one on either side of the spine, and embraced by, but still exterior to the pleura. The pleura pulmonalis and pleura parictalis are everywhere and always in actual contact. It follows that the space of the thorax must be at all times perfectly filled by the lungs and other organs. In figure each lung is conical. The right is wider and shorter than the left, a difference which results from the position of the liver on the right side and the heart on the left. The right lung is cut by deep fissures into three lobes; the left only into two. The base of each lung presents downwards, and rests on the diaphragm ; that of the right is more concave than that of the left. On the right side the liver bulges upwards, encroach- ing upon the chest. The anterior edge of the right lung slopes off obliquely downwards and backwards, so that it projects much lower by its posterior than by its anterior border. On the left side the heart occupies the space which, in the absence from this place of this organ, might have been engaged by a third lobe. The apices of the lungs project above the level of the first rib. The right is higher than the left. The dorsal aspect of the lungs, thick, round, and vertical, is received into the hollow of the ribs near the vertebrae. It is longer than the anterior. The posterior and inferior margins descend into the angular space between the ribs and the diaphragm. The anterior border is thin, irregular, and oblique. That of the left extends forwards over the pericardium. The inner surface of each lung presents towards the mediastinum.. That of the left is hollowed out to receive the heart. The root of each lung is attached to the posterior edge of its inner surface. Each lung is divided into lobes by fissures, which commence near the apices, and descend ob- liquely forwards, to end in the anterior border near the base. The fissure divides the lung, on either side, into an upper small lobe and a lower large one. In the right lung a second small fissure is directed downwards and back- wards from the anterior margin, to end in the great fissure — it cuts off a small triangular piece from the upper lobe, and gives three lobes to the right lung.* From Malpighi to Reisseissen, compre- hending the first historical period of Ana- tomical Science, the structure of the lungs formed a constant ground of controversy. From Reisseissen (1803) to Rainey, Addison, Rossignol, Schultze, Moleschott, and Adriani, the most recent authors, differences on this subject have continued to divide the opinions of anatomists. This question, which involves so much that is historically interesting in anatomical science, divides itself naturally into two primary departments : 1st, the de- scriptive and structural ; and 2nd, the historical bibliography. The Trachea in man extends from the larynxf to the bifurcation of the tube into the right and left bronchi ; its first superior ring, which is attached to the cricoid cartilage, coincides with the upper border of the body of the fifth cervical vertebra : the point of its bifurcation in the thorax is level with the superior edge of the body of the third dorsal vertebra : it averages in internal diameter from £ of an inch to 1 inch, and in length from 4 inches to 4£ inches. J Variations in the length of the trachea are due to the great * For a full account of the relations of the lungs to the thorax and to the neighbouring viscera, see art. THORAX. f See Art. LARYNX. J " Trachea, 3£"— 4£" longa, 8'"— 12"' lata, et e pariete anteriore ad posteriorem, 7'" — 9'" ampla est." — Disquisitiones tie Structura et Textura Cana- lium aeriferum. Scripsit Ernestus Schultze. Mi- tavise et Lipsise, 1850. RESPIRATION, ORGANS OF. range of motion within which the larynx is capable of changing place. The diameter of this tube is greater in the male than in the female, at the lower than the upper ex- tremity ; it is nearly cylindrical in figure, and permanently patulous. It is composed in the human subject generally of about eighteen cartilaginous rings ; of these rings the pos- terior fourth is deficient; the circle is com- pleted at this interval by a musculo-mem- branous structure. The tracheal muscle stretches from one extremity of each cartila- ginous ring to the other: the.trachea is therefore contracted in diameter by muscular action, and enlarged by the elasticity of the ring- cartilages. The rebounding property of these cartilages results physically from their ring- like figure : they tend constantly to straighten themselves; this perpetually acting force preserves the patency of the tube. The con- vexity of the tracheal rings is directed for- wards, the membranous interval being placed posteriorly : by this arrangement the exemp- tion of an important organ from external injury is secured. Against the accident of occlusion during the movements of the neck artful provision is made in the flexible and elastic nature of the structures by which the rings are tied together. The trachea externally is everywhere em- braced in loose areolar tissue : upon this circumstance depends the great range of its longitudinal mobility. Its posterior aspect is in contact with the oesophagus, which is interposed between it and the vertebral column. The recurrent laryngeal nerve, ascending to the larynx, is placed in the in- terval between these tubes. In front of the trachea are situated the sterno-thyroid and sterno-hyoid muscles, which leave an interval in the median line, through which the deep cervical fascia enters to embrace the windpipe. The brachio- cephalic and left carotid arteries, leaving the chest through the episternal notch, lie on the trachea near the top of the sternum : above this limit is observed the plexus of the inferior thyroid veins, and near the larynx it is crossed by the isthmus of the thyroid body : on either side and parallel to it are the carotid vessels and the lobes of the thyroid gland. Entering the limits of the thorax, the trachea is in relation anteriorly with the first piece of the sternum, and the sternal extre- mities of the sterno-hyoid and thyroid, and to the left, in a descending order, with the in- nominate vein, the commencement of the inno- minate and left carotid arteries, which tend towards the sides of the tube, with the arch of the aorta and the deep plexus of nerves, and at the point of its bifurcation it is in contact with the pulmonary artery at the place at which this vessel subdivides into branches. Lying between the two pleurae, the trachea is contained in the posterior mediastinum ; on its right side it is in relation with the pleura and pneumogastric nerve, and on its left, with the carotid artery, the pneumogastric, re- current and cardiac nerves. 259 Structural anatomy of the trachea. — The tra- chea is constructed of cartilage, yellow and white fibrous tissue, muscular fibres, blood- vessels, lymphatics, and glandules, the whole being internally lined by a dense stratum of ciliated epithelium. These parts may best be described from within outwards. The tracheal mucous membrane is a develop- ment of the pharyngeal. (Henle). It forms a Fig. 204. Vertical cutting through the epithelial and sub-epi- thelial layer of the trachea. (After KoUiker.) a, b, basement or homogeneous membrane ; c, the first race or growth of epithelial cells ; c, d, the last, further evolved ; e, the adult, surface, ciliated cells. layer of 0-024— OW7 in thickness; it re- solves itself into two distinct layers, including severally two equally distinct orders of cells ; the undermost, resting immediately on the basement membrane, is composed of orbicular and fusiform particles, measuring from 0*004 to 0-005"', and bearing a clear conspicuous nucleus of from 0*0025 to 0-003.'" The superficial stratum is constituted of the adult cells ; they consist of club-shaped bodies, armed at the free outermost end with cilia (each single cell carrying about 50 cilia)*, and elongated at the proximal end into a long tapering tail : in length these cells average Fig. 205. Separate cells taken from, the epithelium of the trachea, the lowest, smallest, and globular, being the youngest; the uppermost, elongated, and ciliated, the oldest. * According to Valentin's counting, each cell supports no more than from ten to twenty-two cilia ; but I have often reckoned many more. « 2 260 from 0-015 to 0-02"', and in breadth from 0-0025 to 0-004'", according to the measure- ments of Kolliker.* This order of ciliated cells is disposed upon a bed of cytoblasts in a double stratum of about 0'006 to O'OT", in thickness : they differ from ordinary cylinder epithelia in the remarkable length to which the attached extremity is prolonged ; the tail of each cell exhibits quite the character of a yellow filament, and measures from 0*024 to 0-027'" in length. In the centre of the broad end of each of these cells is contained, without exception, a clear, bright, oblong nucleus, of from O'OOS to 0-0045'" in length ; and, further, each nucleus bears a very visible nucleolus (e, fig. 204.). The cell contents consist of minute granules and fat molecules. Valentin de- scribes a double nucleus in many of these cells. The cilia attached to the tracheal epithelium are clear, fine continuations of the cell-mem- brane: they measure 0*0016 to 0-0022'" in length : each cilium tapers to its free extre- mity, that is, it is broader at its base than at its apex. The cilia of the tracheal epithelium are longer and more conspicuous in the em- bryo than in the adult : the current excited by their vibration tends in the direction of the laryngeal outlet of the tube. Proofs will be afterwards adduced that these motive or- ganules enact no part in the office of re- spiration : they subserve a merely mechanical purpose in the process of mucous excretion. These epithelia swell in water, while chromic acid restores them to their original characters (Hannover). By Biermer and Gosselinf, the tracheal cilia have been detected in motion 78 hours after death in man. Under normal circumstances no shedding occurs in the epi- thelium of the air-passages. In disease, however, these cells abundantly desquamate. (See Pathological Anatomy of the Lungs). It thus appears that the cells of the tracheal epithelium proceed from the basement mem- brane (by fig. 204.) in the direction of the surface in successive generations, the youngest (cytoblasts) being the deepest and the next to the blood-supply, and the oldest, the highest and cilia-bearing. It is stated by Hannover J, that this epithelium may be indefinitely pre- served in chromic acid. The tracJieal glands are productions of the mucous membrane of the trachea. The largest and most numerous are situated in the posterior wall of the tube, and possess long excretory ducts (i,fig. 206.), which traverse the whole thickness of the muscular and elastic layers. The glandules themselves are best examined from the outside, and rest on the posterior surface of the trachealis muscle ; they exhibit a slightly reddish colour, and belong to the compound order of glands(/) ; they do not all belong to the same variety ; some coincide in structure with the salivary * Handbuch der Gewebelehre, &c., p. 450. t Verb, der VVurzb. Pbys. et Med. Gesellsch. i. 212. J Mttller's Archiv, 1840. RESPIRATION, ORGANS OF. glands, others with the sudoriferous. Those which are found over the cartilaginous an- terior three fourths of the tracheal walls, are thinly distributed, and penetrate into in- tervals between the ring-cartilages. This class of glands measures from -^L- to •£ of an inch : they are smaller than those which cluster on the posterior surface of the tracheal muscle and which measure from £ of an inch to an inch. In external characters these glands corre- spond with the grape-like compound glands : from the latter, however, they differ in some particulars. It is only the larger variety of these glands which is lined at the tarminal gland-vesicles, with globular epithelium, the ducts being clothed with the cylinder variety. The smaller sort, conforming in this respect with ordinary sudoriferous follicles, are lined throughout with cylinder epithelium. In these latter there is no distinction (except that of size) between the epithelium which clothes the blind extremities of the follicles and that which covers the ducts. These follicles fork at their coecal extremes, each branch measuring from 0'02 to 0-03'" in Fig. 206. i Ideal transverse section of the wall of the trachea. (After Kolliker.) a, areolar tissue embracing the cartilages ex- ternally ; b, c, d, ring cartilage seen in section ; b, outermost layers having flat cells ; c, soft and mid- portion — cells oval ; d, innermost layers with flat cells ; e, sub-mucous tissue ; /, part of a tracheal gland ; g, elastic tissue with longitudinal fibres j h, ciliated epithelium. RESPIRATION, ORGANS OF. 261 diameter, the parietes of which are composed almost exclusively of fine small cylinder epi- thelium. The cylinder epithelium of the ducts of these glands bears no cilia; a character in which it differs from that of the mucous mem- brane of the trachea in general. The ciliated variety ceases at the orifices of the ducts. The secretion of these glands is a limpid, non-corpusculated fluid. Here it is certain that the act of secretion is not synonymous with that of the shedding of the epithelium. Under certain pathological conditions the tracheal glands augment in size, and become choked with epithelial cells.* Fibrous Structures. — In the order from within outwards is next observed a remark- able layer of elastic tissue. It lies imme- diately underneath the mucous membrane (a, Jig. 20±. ; e,fig. 206.). It consists of two varieties of fibre, the yellow and the white. The former lies chiefly on the posterior wall, over the trachealis muscles. Its fibres are here disposed in a regular longitudinal direc- tion. They are gathered into thick bundles readily seen with the naked eye, even through the mucous membrane, of rl? of an inch in thickness. They descend in a ser- pentine manner along the posterior aspect of the trachea, and will be afterwards traced on the bronchi. They frequently anasto- mose. Smaller fibres, forming a thinner layer of the same tissue, are distributed over the anterior walls of the trachea; like the former portion, running under the mucous membrane and preserving uniformly a lon- gitudinal course. Another order of elastic tissue lies between the ring-cartilages, tying them together cylindrically. Of this tissue the fibres are more slender than those of the former, and belong to the white variety (Bowman). It is to the elastic property of this tissue that the trachea owes its power of lengthening and shortening, a power which in birds is more remarkable than in mammalia. The tracheal cartilaginous rings come next to be described. Each cartilage forms a little more than three quarters of a circle ( e>fig- 207.). It embraces the anterior three- fourths of the tracheal tube. The deficient portion, comprising the remaining fourth of the circle, is completed by muscle and mem- brane and elastic tissue (k, Jig. 207.). This * " Die Driisen des Kehlkopfs und der Luftwege liberhaupt warden bei Catarrhen haung verandert, so dass ihre Blaschen bis 0'08 selbst 0-15'" messen und mit kleinen rundlichen Zellen erfult sind, die wohl den auf Schleimhautoberflachen sich bilden- den Schleimkorperchen sich vergleichen lassen." — Kolliker, Anat. Mik., p. 452. " Interdum hse cryptae mucosae amplificatae, ita ut pane V" latae sint, et sinubus secundariis in- structae reperiuntur. In hoc casu illae saepe usque in regionem plexuum vasorum postea et porrigun- tur. In preparatis per longum tempus in spiritu vini asservatis aperturae harum cryptarum muco- sarum nudis oculis optime cerni poterant, atque imprimis numerosaa in parietis anterioris interstitiis non cartilagineis et in pariete posteriore animad- vertebantur." — Disq. de Struc. et Text. Canal, aerif. S. E. Schultze, 1850. description applies only to the case of the human subject. In the sheep the posterior Fig 207. Transverse section of the tracliea t/trough the middle of (and parallel with} one of the cartilaginous rings. (After Schrdtz.') a, ciliated epithelium, lining the inside ; 6, elastic longitudinal tissue ; k, the tracheal muscles ; e, ring cartilage ; /, external areolar tissue ; i, blood- vessels ; 2, tracheal glands. ends of the tracheal cartilages meet, to pro- ject behind as spinous processes, thus con- cealing the trachealis muscle. In the horse the same parts of the ring cartilages over- lap. This arrangement prevails also in the dog. In the ox the posterior ends of the tracheal rings are everted. Each cartilage is embraced in a fibrous perichondrium (f,Jig. 207.) which is intimately united to the inter-annular fibrous tissue. In ultimate structure these cartilages are chiefly composed of cells interspersed through a fibrous basis (b, c, d, c, by Jig. 206.). The cells are largest and doubly nucleated in the centre of each cartilage (rf). At the inner and outer surface these cells become flat- tened and elongated (6, i). In different parts of a vertical section of the cartilage they present different directions as regards their long axes (r^,}Ni Diagram of portions of the human lung imperfectly injected with wax, exhibiting the mode in which the intercellular passages a, a, a, spring from the ultimate bronchi b, b. These are smooth-walled, those alveolated. (Original.) Frequently they multiply dichotomously (6, fig. 210.) 5 that is, a single tube divides into two of equal diameters. Sometimes the main bronchus exhibits a zigzag outline, the branches proceeding from the alternate angles. This latter method obtains with great con- stancy in the case of the intralobular bronchi. The number of branches within the lobule into which a bronchus subdivides bears a general proportion to the size of that lobule. In the smallest, the intercellular passages begin from two or three bronchial peduncles ; in the largest, from eight or ten. In some instances a second or supplementary bronchus enters a lobule at the side. It is, however, the rule, that each lobule is supplied only with a single central bronchus. The point of attachment of the bronchus is the apex («) of the lobule (6) ; the opposite point being the base. The angle of division in the bron- chial tree is, for the most part, the obtuse. This disposition of the tubes favours, mecha- nically, both the ingressing and the egressing column of air.* It has been maintained by Dr. Radcliffe Hall I, that the contractility of the bronchial tubes is called into action rhythmically in each expiratory movement, to assist in emp- tying the lungs. But no evidence has been adduced in support of this doctrine. If the contraction of the bronchial tube, through muscular or any other force, occurred at the first stage of the act of expiration, it is ob- vious that it would arrest rather than favour the egress of the air. It is not, however, im- probable, that a certain regulated power over the outgoing column of air is exerted by the parietes of the bronchial tubes. This is more likely to consist in a shortening and length- ening of the tubes. They may also serve to regulate the supply of air to the lobules, in accordance with the wants of the system, just as the contractility of the minute arteries regulates the supply of blood to the organs to which they proceed. J It may possibly be through this channel that the remark- able variation is effected in the amount of respiration which adapts the quantity of heat produced to the depression of the external temperature. It has been further suggested by Dr. W. Gairdner $ that the contractility of the smaller bronchi may serve to expel col- lections of mucus which may accumulate within them, and which neither ciliary action nor the ordinary expiratory efforts suffice to displace. Ultimate pulmonary tissue. — Lobules. — Historical bibliography. — From the dawn of anatomy to the present age, " the struc- ture of the lungs " has proved a fertile theme for disputation. Anterior to the era of Mal- pighi, anatomists were wont to regard the Jungs as consisting of " a spumous tissue," in which air and blood became directly inter- mixed. Malpighi|| first demonstrated the untenableness of this view. He placed the fact beyond doubt, that the air and the blood were contained in separate channels.f He described the air-cells, and contended that they communicated among themselves, but not with the blood passages. In the year 1665, Bartholin wrote to de- * " Rien n'est plus varie' que la longueur de ces rameaux, le mode de ramification qu'ils subissent, le nombre de leurs subdivisions et la direction que celles-ci affectent. On peut cependant les rapporter a deux types principaux : le premier comprend les tubes aeriens qui sont soumis au mode de division par ramifications akernes ; le second, ceux qui sub- issent la loi de dichotomic ou de trichotomie." — Re- cherches sur la Structure intime du Poumon de 1'Homme, &c. par M. Rossignol. Bruxelles, 1846. •j- Trans, of Prov. Med. Assoc. 1850. J Carpenter, Principles of Human Physiology, p. 514. § Edinburgh Monthly Journal, May, 1851. || Marcellus Malpighi, Opera omnia, Lugd. Ba- tav. 1687, p. 320. Lettre premiere. stretching on either side along the circumference of the membranous leaflets, pre- venting, by their continuously acting elasticity, the injurious folding of the latter, and, therefore, the tangling of the respiratory web of capillaries. The extremities of these processes are produced by means of the curled elastic fibres shown in the plan. The dotted lines define the area of the re- spiratory membranous leaflets supporting the ca- pillary network. * See Yarrel on British Fishes ; Lecons d'Ana- tomie Comparee, par M. Cuvier; Owen's Lec- tures on Comparative Anatomy, vol. ii. ; Monro, on the Structure and Physiology of Fishes, 1785 ; Art. PISCKS, in this Cyclopaedia; Wagner's Ana- tomy of Vertebrated Animals, bv Tulk, 1845. RESPIRATION. 29i the soft structures. This part is represented transversely in Jig. 238, in which also the disposition of the constituent cells may be remarked to bear advantageously upon the mechanical functions of the parts. As regards the arrangement of these cells, this piece in the framework of the gill-process may be divided into two parts, by a longitudinal "line, on the outer side of which the long axes of the cells, which are oblong, are directed transversely with respect to the inner: the axes of the cells are parallel with that of the processes of which they are the constituents parts. This arrangement is most distinctly marked in those genera in which the skeleton is little calcified. Functionally considered the piece occupying the blunt edge of the process de- termines its penknife-like contour, and confers strength and straightness of direction, thus favouring the contact between the respiratory foliage and the surrounding medium. It dis- charges the passive office of sustaining the soft structures and of extending the plane superficies over which the branchial blood- vessels are distributed. The internal or acute margin of the bran- chial process conceals, in the recent structures, under the lab\ rinth of the superimposed re- spiratory membrane, a skeletal mechanism of singular novelty and beauty (f, Jig. 238.) From the innermost side (near its root) of the denser piece which lies parallel \\ith the outer margin of the lamella, a less dense, more transparent, and more cartilage-like process (d,Jig. 238.) rises, to advance along the in- ternal margin of the lamella from its base to its extreme apex. From either side of this process, at right angles, processes (f and cc), still more slender, delicate, and trans- parent, are detached, to follow for some dis- tance the circumference or free margin of the membranous leaflet on which the vascular network is outspread. This part of the skeletal fabric of the branchial lamella is actively and importantly concerned in the mechanism of the respira- tory function. It is to the branchiae what the ribs are to the mammalian lungs. The fine extremities of these transverse portions, as seen in c, c, taper off into a species of curly fibre, which travels accurately along the extreme margin of the membranous leaflets to the point («) at which the latter rest upon the flat surface of the osseo-cartilage of the obtuse margin. The axis which sup- ports this system of elastic " ribs " (in sec- tion at c and d) exhibits under the mi- croscope a median transverse line appa- rently filled \\ith an oleaginous fluid, which communicates with the moniliform system of cells, occupying the axes of the curved pieces (c, c), where probably it performs the two-fold office of mechanically distending and nourishing the parts. No vestige of an Ha- versian order of canals can be discovered in any portion of this branchial framework. The calcareous granules of Tomes are dis- tributed irregularly over the parietes of the cartilage cells. It is not easy to misappre- hend the office which devolves upon this apparatus. By means of two needles the recent branchial ray may be separated into two longitudinal halves, to the inner of which, exclusively, the membranous leaflets remain adherent, a circumstance which illustrates the anatomical connection between these softer parts and the delicately adjusted framework of the internal border of the leaflet. The elastic transverse processes (c, c), from their constrained curved position, constantly tend to straighten themselves, and to convert the curved into a direct line of action. This straightening tendency, which is a constantly and unremittently operating force, constitute the immediate agency under which the tang- ling, folding, or crumpling of the leaflets bearing the capillary network is rendered impossible. Under the ceaseless operation of this resilient property, the true breathing surface is regu- larly maintained in a state of uniform exten- sion, and that at a degree of lightness, measured with wonderful precision, to suit the exigencies of structures so surpassingly refined. A superficial consideration indeed might have sufficed to render it improbable, that a system of blood- channels of such ex- treme delicacy as that which constitutes the breathing apparatus of fishes could exist un- injured, unless by aid of a basis of support at once appropriate in its physical qualities and mechanical disposition. Morbid anatomy of the lungs and air pas- sages. — It is possible in the space here al- lowed to do little more than to enumerate the pathological conditions to which these parts are liable. The diseases of the lungs and bronchi since the era of Laennec have re- ceived a considerable share of the attention of pathologists. The normal anatomy of the lungs is now known with precision. The characteristics of the alterations of structure which in disease they undergo, within recent years have also been defined with correspond- ing precision. The community between the bronchial and pulmonary circulation established by the recent researches of Dr. Heale, will probably oblige pathologists to modify their views with respect to the supposed distinct- ness and independence of the diseases of the lungs and the bronchi. The following tabu- lated arrangement, as given by Rokitansky, in the 4th vol. of his Pathological Anatomy, ex- hibits the abnormal conditions of these parts in lucid summary. 1. Deficiency and excess of formation. 2. Deviations in size. a. Morbid dilatations of the air passages. b. Dilatations of the larynx and of the trachea. c. Dilatation of the bronchi. d. Contraction of the air passages. e. Hypertrophy and Atrophy. 3. Deviations in form. 4. Deviations in position. 5. Interruptions of continuity. 6. Diseases of texture. A. Diseases of the mucous membrane and of the subjacent areolar tissue. a. Ilyperiemia and Anaemia. b. Inflammations of the mucous membrane. u 2 292 RESPIRATION. 1. Catarrhal inflammation. a. Acute. b. Chronic. 2. Exudative processes (croupous inflam- mation.) 3. Pustular inflammation. 4. The typhous process on the mucous membrane of the air passages. c. Inflammation of the submucous areolar tissue. d. Ulcerous processes. e. (Edema of the mucous membrane of the air passages. /. Gangrene of the air passages. g. Adventitious products. B. Diseases of the cartilaginous skeleton of the air passages a. Inflammation of the perichondrium of the laryngeal cartilages. b. Inflammation and softening of the epi- glottis. c. Ossification. d. Adventitious products. 7. Anomalies in the contents of the air passages. Abnormal Conditions of the Lungs. 1. Deficiency and excess of formation. 2. Anomalies of size. — Hypertrophy and Atrophy. 3. Anomalies in form and position. 4. Diseases of texture. a. Rarefaction of the pulmonary tissue (Emphygema.) b. Condensation of the pulmonary tissue. c. Ilypaeremia (stasis). Apoplexy of the lungs. d. Anaemia of the lungs. e. (Edema of the lungs. j\ Inflammation of the lungs (Pneu- monia). 1. Croupous pneumonia, typhous pneumonia. 2. Catarrhal pneumonia. 3. Inflammation of the interstitial tissue of the lungs (Interstitial pneumonia). g. Deposits in the lungs (Melastatic processes). h. Gangrene of the lungs. i. Softening. k. Adventitious products. The preceding distribution of the morbid conditions of the air passages may be advan- tageously methodised under two heads : first, those of the bronchi (as defined in the account of their normal anatomy) ; secondly, those of the lungs. The bronchi are liable to several forms of inflammation : a. Acute bronchitis. b. Chronic bronchitis. c. Plastic bronchitis. Collapse of the lungs should be considered, pathologically, as rightly ranking under the denomination of the diseases of the bronchi. The various forms of asthma, and hooping cough, belong to this species.* The bronchi are subject to two forms of dilatation. In the first, a tube is uniformly dilated at every part of its circumference. In the second, the dilatation is saccular. The * For an account of the morbid statis of the larynx, and upper part of the trachea, see Art. Larynx. small bronchi and those near the surfaces and borders of the lungs are most liable to suffer this change. The walls of the tubes at the dilatations are hypertrophied and thickened. Sometimes, with the saccular variety, the same parts are relaxed and attenuated. The bronchitic collapse of the lungs occurs under two distinct aspects, the diffused form, and the limited or lobular form. Of these the latter variety is the more striking or cha- racteristic, and has been, especially in the lungs of children, the subject of more discus- sion than the former. But the diffused form is by far the more common, and is of frequent occurrence in its slighter degrees. In both conditions the pulmonary tissue presents a dark violet colour as seen beneath the pleura ; internally it is red. In considering the causes which tend to produce this condition they seem to resolve themselves into the following: 1st. the exist- ence of mucus in the bronchi, which is more liable to produce obstruction according as it is more thick and viscid ; and 2ndly, weakness or inefficiency of the respiratory power; Srdiy inability to cough and expectorate. Of these conditions, the first must be considered as the exciting cause, the others as predis- posing, co-operating with the first, but in- capable, without it, of producing collapse.* With bronchitic collapse of the lung is almost always associated emphysema of the unaffected portions of the same lung(Gairdner). Inflammation of the mucous membrane of the bronchi produces changes which are denoted by redness and tumidity of the tissue, a secretion of muco-serum, purulent mucus, or pus, according to the stage and intensity of the inflammation. This latter is the condition of superficial suppuration. The swelling of the mucous membrane and sub-mucous tissue, which as- sumes the form of watery infiltration into the * For a full discussion of this interesting subject, see " Pathological Anatomy of Bronchitis, and the Diseases of the Lung connected with Bronchial Ob- struction." By W. T. Gairdner, Edin. 1850. Md- moire sur une Distinction nouvelle de deux Formes de la Bronchite ; precede' de quelques considerations generales sur I'lnflammation de la membrane mu- quese des voies-aeriennes. Par J. H. S. Beau. Archives Generales de la Medicine, Sept. et Oct. 1818. Memoire sur quelques Parties de PHistoire de la Bronchite et de la Broncho-pneumonie chez les Enfants. (Archives Ge'nerales, Oct. 1851, et suivantes.) Memoire sur la Broncho-pneumonie Vesiculaire chez les Enfants. (ReVue Me'dico- Chirurgicale de Paris, 1852. Par les Drs. Barthez et Rilliet.) Traite Pratique des Maladies des Nouveaux-Nes, &c. Paris, 1852. Par M. Bonchut. A Memoir by Legendre and Bailly, in the Archives Ge'ne'rales de Medicin, on the " e'tat foetal " of the lungs, torn. Ixiv. On the Diseases of the Organs of Circulation and Respiration, Art. Atelectasis. By Hasse. Sydenham Society. Die Bronchio-pneu- monie der Neu-gebornen und Sauglinge. Berlin, 1837. By Seifert. Medico- chirurgical Trans., for 1830. By Dr. Alderson. Der Mechanismus der Re- spiration und Circulation. By Mendelssohn. Beitrage zur Experimentellen Pathologic und Physiologic. By M. Traube. Die Bronchitis der Kinder.' Leipzig, 1819. Dr. Fuchs. Diseases of Infancy and Child- hood. West. RESPIRATION. 293 areolar tissue, being accumulated at individual spots, is important and worthy of great atten- tion, on account of the facility with which it interferes with the calibre of the tubes, Chronic inflammation of the bronchial mem- brane gives rise, especially in parts abounding in glands, to glandular hypertrophy, mucous polypi, epithelial growths, spongy and velvety thickening, relaxation of the muscular and fibrous elements, fol lie ular ulceration, £c. The pathological conditions of the broncho- pulmonury mucous membrane differ in no respect from those of any other membrane of this class. In plastic or exudative bronchitis are cha- racterised by a morbid action of a croupous nature. In bronchial croup the tubular exudations from the larger bronchi present a calibre in- versely proportional to their thickness, and those thrown off from the finer ramifications occur as solid cylinders. Asthmatic affections may either have their exciting cause in the lungs or in the condition of some remote organ. They partake of a nervous and muscular character, and are frequently caused by a collapse of a portion of the lung. The collapsed part operates as an excitor of the muscular spasm. English pathologists recognise the follow- ing forms of disease proper to the parenchyma of the lungs: — Pneumonia, or inflammation of the cell-tissue of the organ ; gangrene ; /KEinorrhage ; oedema ; emphysema ; phthisis ; cancer. Inflammation of the vesicular tissue of the lungs is marked by the exudation of the co- loured elements of the blood. This fact was once supposed to prove the absence of epi- thelium in the air-cells. This inference is erroneous. Inflammation of the lung is divided into three stages, according to the consistency or physical condition of the exuded product. The first is that of engorgement ; the second is that of hepalisation j the third is that of grei/ hepatisation. Gangrene of the lungs occurs under two anatomical forms, the diffused and the cir- cumscribed. Cancer of the lung, most commonly of the encephaloid species, occurs in the forms of secondary nodules and primary infiltration, accompanied or not by tuberous formation on either mediastinum about the main right bronchus (Walsh). The anatomical changes which occur in the lungs in phthisis are referrible to three main stages, corresponding habitually to certain varieties in the symptoms, and always to modifications in the physical signs. The first stage is that of deposition and induration; the second that of softening; the third that of excavation. The exact scat of pulmonary tubercle has proved, from the dawn of pathology to the present time, a controverted point. The question is whether the deposit of the morbid product occurs first on the free surface of the air-vessels into the substance of their walls, or between them into a supposed inter- vesicular tissue. From Morton and Bayle to Rokitansky and Lebert, advocates for each of these " seats of election" have contended in turn. The free or aerial surface of the air-cells is now the commonly accepted si- tuation of the tuberculous deposit. The nature of the tuberculous matter is not less disputed ; witness the following defi- nitions : — Tubercle is a specific exudation (Ancell). Tubercle is a degraded condition of the nutritive material (Dr. C. J. B. Williams). Tubercle is composed of the products of inflammation (Reinhardt). Tubercle is composed of the dead-tissue elements (Flenle). Tubercles themselves consist of abnormal epithelial cells (Dr. W. Addison). Tubercles are composed of metamorphosed organised elements; a metamorphosis co- ordinate with the fatty and the waxy de- generations (Virchow). Tubercle is a product secreted from the blood by the epithelium lining the air-cells (Schroeder Van der Kolk*). The mechanism of emphysema is still sub judicc. Some authors, with Laennec, ex- plain it on the supposition that the walls of the air-vesicles yield under the force of the air when the expiratory current is impeded. Another class of writers attribute it to an excess in the inspiratory force. Mr. Rainey contends that the parietes of the air-cells suffer a change of structure by fatty dege- neration,, and that this change stands to em- physema in the relation of a causal condition. Dr. Gairdner affirms that emphysema of one portion of the lung cannot occur unless a col/apse has happened in another part. Em- physema fills up pneumatically the space lost by the collapse, and no more. The chest ean only be filled; it cannot be inflated beyond a given inspiratory limit. The air- passages of the emphysematous portions are free, not obstructed. If already the cavity of the thorax be uniformly filled, it is certain that emphysema is rendered physically im- possible. Emphysema is plenum counter- balancing collapse — a vacuum. It is yet by no means determined to what extent, if at all, the shedding or desquamation of the epithelium of the air-passages takes place in disease. ( Thomas Williams.') STOMACH AND INTESTINE.— (Syn. Stomach, formerly Maiu, Eng. ; Magcn, Germ.; oro/udxo^, O'ao-rrjp, Gr. ; Stomachus, Ventriculus, Lat. ; Stomaco, Ventricolo, Ital. ; Estomac, Fr. ; Estomaco, Sp. ; — Intestine or bowel, formerly gut, tripe, cut rail, Eng.; Darm., * See British For. Med. Chir. Rev., for January April, July, 1853 ; in which Nos. respectively three excellent articles by Paget, Jenner, and Sieveking, will be found. u 3 294. STOMACH AND INTESTINE. Germ. ; evrepoz/, Or. ; Intestinum, Lat.;Inlcstino, Ital. Sp.; Ititestin, Fr.*) What are called the organs of the animal body consist of a diversity of tissues, so grouped and united with each other as to form a more or less continuous and aggregate mass ; — the functions of these various struc- tures being also associated in a single general purpose, which may be regarded as the sum of their several actions on the system at large. Among such groups of structures, there is none more remarkable than that which effectuates the series of processes collectively termed DIGESTION. For other organs are so far exclusively dependent on the blood, as that many influences of the outer world can scarcely reach them, except through the medium of this fluid. Entrenched, as it were, behind this the great river of ani- mal life, they are secured from any but the indirect action of ^ numerous physical agents. But the organ of digestion lies out- side this stream : and occupies a kind of neutral territory, between life and matter, where the various forces of both can co- operate for its benefit, in equal and har- monious conjunction. Or rather, let us say, the digestive canal is the threshold of the House of Life, where dead matter is first endowed with those properties which enable it to become a living constituent of the animal body. The group of organs before us has indeed a special relation to the animal. For although digestion is usually enumerated amongst those general or organic functions which are shared in by everything that has life, — vege- table as well as animal, — still the means by which the process is effected in these two forms of organization, constitute as important a distinction between them, as the mere pre- sence or absence of other functions. So that, the digestive cavity is, on the whole, as charac- teristic of the animal, as the organs of loco- motion and innervation of which it is the exclusive possessor. How far the so-called vegetative functions are really alike, or even comparable to each other, in the two kingdoms of nature, it is not our object here to inquire. As little do we wish to introduce, what some might perhaps think less out of place, a detailed comparison between the digestive functions of the plant and animal. But as the cavity which it is our express object to describe is all but univer- sally present in the latter, and absent from the former organization, it seems desirable briefly to contrast them in this respect. * In respect to the etymology of these names we may conjecture as follows: — The word r»*«). Maw and magen are de- rived from its relation to food (meat). Intestine, ivrt'ov, entrail, ventriculus, (and darm?) connote its internal and hidden position. Bowel (botellus), and tripe (Tg/T»v), refer to its convoluted or tortuous form : gut (gcotan, Anglo-Saxon, to pour), to its car- rying fluent contents. In the animal, a highly azotized composition is connected with, — and probably essential to, — an active life; which, in its turn, implies a rapid waste of substance. On the other hand, the plant lives slowly, wastes little, and contains but a small quantity of azotized material. The food of each appears to correspond with these requirements. That of the plant is, in great part, inorganic ; consisting mainly of compounds which pervade the soil that surrounds its roots, or the air which bathes its leaves. While that of the animal is or- ganic : — i. e. the substances which compose it are the products of a previous organization. The elaboration of the food repeats the preceding contrast. The plant builds up in- organic into organic matter; — a process of chemical synthesis, which may well be effected with great difficulty, and by slow stages. While the animal scarcely does more than convert one proximate principle into another ; — a meta- morphosis which involves no change of com- position, and the facility of which is but par- tially counterbalanced by its requisite rapid- ity and amount, and the delicacy of its ad- justment. The agents of these processes are also susceptible of comparison. For in the vege- table they appear to be closely connected with various external forces, such as light and heat; while in the animal they seem more inherent to the organism.* And in both, the site of the elaboration or change in the food corresponds to those situa- tions where the above agents are most readily applicable: — viz. in the plant, to the leaves and other green parts of its surface; in the animal, to a cavity in its interior. The pre- sence of such a cavity not only permits the less frequent application of nutritious substance to be compensated by the ingestion of large quantities at particular times ; but, while it thus meets the peculiar requirements of an animal organism, also allows of that loco- motion which is so necessary to the mere prehension and selection of its scarcer food. Its subjection to volition renders ingestion a work of rapid and powerful mechanical force, in place of a slow physical imbibition. And finally, the same internal situation which directly subjects its contents to the agents of the digestive metamorphosis, also isolates them from all surrounding objects, besides favouring the temperature often necessary to the operation. f * Traces of this contrast between the animal and plant, during life may be found in those processes of putrefaction and eremacausis which respectively effect their dissolution after death. f Hence, instead of a digestion corresponding to that of the animal, the plant presents us with a pro- cess in which mere reception is so predominant, that we might almost compare it with the absorption of the chyme and chyle into the blood. As a kind of fanciful corollary to this, we might regard the crust of the earth, and the atmosphere which sur- rounds it, as forming a common stomach or recep- tacle of food for the whole vegetable kingdom. l('or they include, or receive, detain, and give up, the che- mical food of the plant ; — in quantities Whichjthough STOMACH AND INTESTINE. 295 The reader will, however, observe, that the is aided by a dental apparatus, in the shape title of the following article does not announce an essay on the process of digestion, or the various organs which effect it; but limits itself to two portions of the alimentary canal, hitherto undescribed in this work. But it is impossible to treat of the functions of the stomach and intestine except in connection of a hollow cylinder enclosing long teeth, — as in the genus Napula. The Rotifera are so named from the cur- rents produced by their prehensile cilia i which are here limited to groups surrounding the mouth of the animal. Many of them have an organ of mastica- TM ' 11 • . /• • with the entire process in which they take so tion. This usually consists of three pieces : large a share. \Vhile the numerous observa- — each of the two facets of a kind of anvil being tions and researches which have been made worked upon by the rough or toothed terminal since the appearance of the earlier article surface of a recurved jaw, the longer limb of DIGESTION require some notice in the which receives a muscle at its extremity. Supplement of which the present essay forms The intestinal canal generally exhibits a apart. For these reasons the author has felt pharyngeal enlargement, which is followed it advisable not to confine himself too strictly by a narrow "oesophagus," of varying length, to the exact limits uhich the heading " Sto- mach and Intestine'' might seem to imply. Hence, though the following essay will treat ending in a wider "intestine." In the Gasterodela a dilatation, called a stomach, pre- cedes the intestine. In the Rotifer vulgaris chiefly of the above segments of the alimentary and others, an almost globular enlargement of canal, it will also comprise a very brief account the narrow canal is so immediately followed of whatever is at present known concerning the w hole digestive act. Commencing by a rough by the constricted cloaca, as to have been com- pared to a large intestine. The organ of sketch of the anatomy of these parts in the digestion is also often complicated by the animal kingdom, we shall successively consider, their structure and functions in the human subject ; their relation to digestion and nutri- tion ; and finally, their appearances in disease. COMPARATIVE ANATOMY.— In the Infuso- presence of blind tubes ; which vary, not only in number and size, but also in posi- tion, and possibly in import. Thus they may open, either into an uniform and narrow canal, or into the commencement of the intestine, ria, whose minuteness places them at the or into the presumed gastric dilatation ; — or, lowest extremity of the animal kingdom, the c~~ "' " organ of digestion has already attained such a development as to form the chief basis of their nomenclature. One or two genera present us with a rare finally, as in the Digltena lacustris, a set of such tubes may occupy both of these latter situa- tions. The various members of the order Entozoa are grouped together in obedience to a cla.ssi- and exceptional condition : — viz. the absence fication which is here and there arbitrary and of all traces of digestive cavity. Such are the anomalous, but in the main both natural and useful. It offers three chief varieties of the digestive organ, all of which are very inte- resting. a. In many — as in the Echlnococd and their congeners — no trace of a special digestive cavity is present. Without mouth, stomach, or intestine, the creature floats free parasitic Gregarina and Opalina ; in whom, as in some of the Entozoa, digestion and absorption appear reduced to a simple phy- sical process of endosmose, which carries the nutritious substances dissolved in the fluid medium they inhabit at once into the mass of their corporeal juices. The Poh/gristria possess a plurality of in the cavity of its enclosing cyst, or buries stomachs or internal sacs ; and the relations its barbed head in the tissues of a living of these to the intestine, together with the con- habitation; — whose juices, thus brought into dition of the latter tube, subdivide this group relation with its exterior, are applied to its into numerous families and genera. Thus nourishment by what seems to be rather a many are named "anenterous," because they process of endosmose than of digestion pro- appear to be devoid of intestine. Of these the perly so called. Monas termo — which has four or five globular /3. In other genera belonging to the Cestoid stomachs, of 5TTjL_^th of an inch in diameter, and Trematoid divisions, there is, however, appended immediately to its mouth — may be a canal, which is apparently related to digestion, taken as the type. Others possess similar and the main features of which — repetition sacs in connection with a simple Intestine ; and ramification— may be represented by the and are chiefly distinguished by the straight, Teenia and Distoma respectively, curved, or wavy course of this canal, — or by For example, in the Tape- worm, a minute the single or double character, and lateral or mouth opens into a slender tube, the bifurca- terminal position, of its apertures. Most of tions of which reach the margins of the body them devour a living prey of kindred Infuso- where this begins to assume its regular jointed form. From hence onwards the canal might be compared to a ladder, with rungs at the fore and aft extremity of each joint, at the right angles of which its longitudinal and transverse branches unite. It is probable that ria; — prehension being often visibly effected by cilia, the voluntary action of which carries a current of food into the mouth, or removes egesta by a simple reversal of the stream. And sometimes this act of ingestion ordinarily sufficient, are capable of being locally- exhausted by the excessive demands of a particular clo^s or specie*, and renewed by an artificial supply. these canals possess valves. But whether tney have any constant or valid terminal ori- fices seems doubtful. u 4 $96 STOMACH AND INTESTINE. Many species of Distoma or Fluke may be regarded as types of an arborescent or rami- fied digestive tube. From a mouth which is suctorial — and sometimes visibly muscular — a canal passes backwards, to divide into two large branches. These run along the margins of the oval and flattened animal, giving off other branches ; from which proceed a final series of anastomosing twigs. y. In many creatures closely allied to the preceding by conformation and habits, this ramified canal is reduced to its primary bi- furcations, the ends of which are sometimes slightly dilated. Occasionally there is an enlargement, which has the situation of a pha- rynx ; and which, in a few instances, encloses an apparatus perhaps masticatory. In the genus Diplostomum and others, a distinct set of vessels, which occupies the immediate neigh- bourhood of the intestine, has been supposed to represent a chyliferous or vascular system. As regards these latter forms of digestive apparatus, it may be conjectured, that the ramification witnessed in the Tcenia is re- ferrible, not so much to that mere vege- tative repetition of similar structures which affects the whole animal, as to a merging of the digestive in the circulatory function. In any case, the more simple form of tube •last mentioned appears rather akin to an advance, than to a retreat, of development ; while it sometimes visibly coincides with the appearance of a new system of canals, con- nected with the circulation of a proper nu- trient fluid. In the Nematoid Entozoa, the alimentary canal is generally a straight tube, which oc- cupies the axis of the vermiform animal, and opens at its extremities. In most genera — as in the Trichina, Tricocephalus, Ascaris, Slrongylus, and others — it widens posteri- orly ; where it often experiences a further dilatation, which only ceases near the anus. Rarely, other indications of separation are added: — an oesophageal dilatation, as in the Ascaris lumbricoides ; or an enlargement cor- responding in position to a stomach, as in the Linguatula and Filaria. Rudiments of the organs accessory to di- gestion have also been detected. Blind tubes opening into the canal near its mouth are found in several genera : and the position of these has sometimes led to their being re- garded as salivary. While rarely there is a tube which opens into the intestine in the situation of a biliary organ. In the mode of attachment of their diges- tive canal, this division of the Entozoa otfers a marked contrast with the preceding. In the Sterelmintha (or solid worms) the tube is scarcely distinguishable from the mass of the body. While in these Ccelclmintha (or hollow Nematoid worms), it is suspended from the wall of the belly by filamentous processes. And though such an acquisition of an abdominal cavity is no doubt partly referrible to the isola- tion demanded by the organs of locomotion, yet not only does this itself imply a genera! 'advance of development, but it is actually accompanied by a curious structure, which is apparently connected with nutrition, and pos- sibly renders the cavity of the abdomen the receptacle of a kind of chyle. Its more perfe:t form in the Ascaris lumbricoides may be briefly described as consisting of a series of pyriform processes, the peduncles of which are seated immediately upon the mesenteric filaments previously alluded to, and which project freely into the abdominal cavity, so as to be sur- rounded by the serum and grey transparent substance that fills this space. Their shape resembles that of the villi of higher animals; and their size increases towards the median line of the body. The alimentary canal of the Polyp exhibits so wide a range of development, that while by one extreme it approaches that of the sim- plest anenterous Infusoria, by the other it attains a complexity akin to that of the highest Invertebrate. The Hydra is little more than a stomach or sac, fixed by a sucker at its closed extre- mity, and having at its other end a mouth sur- rounded by prehensile tentacles. Digestion is, however, energetic. The living prey, which is paralysed by the deadly grasp of the ten- tacles, undergoes a rapid solution in this sto- mach, while its colours often visibly mix with those of the parietes common to the organ and theanimal; and finally, its excrementitious residue is speedily rejected by the same orifice through which it previously entered. In other solitary Polyps — for example in the marine Actinice — the folded bag formed by the stomach is separated from the mouth by an oesophageal constriction. It is at the same time attached to, and isolated from, the general wall of the animal, by radiating mus- cular bands ; which extend vertically down the whole depth of the organ, so as to resemble the septa of a poppy capsule as seen in a transverse section. The compound Polyp appears chiefly to vary from this type by virtue of its individuals possessing a common stem, the proper nutri- tion of which requires it to be closely con- nected with the organ of digestion. Thus, in some of the Antkozca which possess a stomach very similar to that of the Sea-ane- mones just described, an orifice of small size at the bottom of the gastric sac seems to admit the results of digestion into the general cavity of the animal, within which they experience a kind of circulation. In the Tubularian Polyp, the canal is modi- fied by the addition of a structure which may be regarded as a pharyngeal proboscis. It is a globular projection, surrounded by tentacles at its free extremity, and by its other end received immediately within a circle of simi- lar organs;— the place of its attachment being marked by an internal constriction, through which the cavity of this appendix communi- cates with that of the stomach. In many of these Polyps, the stomach has been seen to possess a ciliated lining ; and there are grounds for presuming the ex- istence of a similar structure in several other STOMACH AND INTESTINE. 297 species. Some of the circulatory movements observed in their ingesta are perhaps accom- plished by the aid of such an apparatus. While their vigorous and almost peristaltic character in other instances is due to structures, the voluntary and powerful contractions of which entitle them to rank as muscles. The cilio-brachiate Polyp possesses an ab- dominal cavity occupied by fluid, in which the alimentary canal is free to move. The canal itself has a mouth and anus, which are both situated at the free extremity of the animal ; — the former orifice being within, the latter without, its whorl of tentacles. The mouth opens into a pharyngeal dilatation, from which a narrow tube leads into an organ analogous to a gizzard. This organ possesses radiating muscular fibres, and rhomboidal teeth, that are capable of crushing its contents. Immediately beneath it is the stomach, in shape like a two- necked flask, and having its blind extremity fixed to the attached base of the animal by a retractory muscle. The pyloric aperture is guarded* by cilia, which rotate, and thus delay, the food. The intestine is narrow and simple, and its excrementitious contents are expelled from the anus, to be immediately hurried away by the current arising from the action of the neighbouring cilia. The body of the Acalcphcc generally con- stitutes a disc with a fringed margin. It is convex above, and concave below, with large dependent processes. And it swims by what seems to be an alternate preponderance of contraction in these two surfaces. The condition of the alimentary canal is here very remarkable. The Entozoa have already offered us a ramified tube, that could scarcely be regarded as strictly diges- tive. But these Sea-nettles further com- plicate this branched state by the posses- sion of a central cavity. This is sometimes placed between a convergent and a divergent set of anastomosing canals ; and sometimes approaches the stomach of the Distoma in possessing the latter set only. In the latter case, the so-called stomach communicates, by a short and simple tube, with the centre of the lower or concave surface. And in one species it also radiates unbranched tubes which open on the margin of the disc. The movements of the contents of these canals seem to be effected by cilia. The ramifications of the canals chiefly occupy the under surface of the animal. The large order of Echinodcrmata again presents us with an important advance of development in passing from its lowest to its highest members. Thus the alimentary canal of the Asterias has a single aperture on the under surface of the animal. This leads by a short tube to a central cavity, which divides into two pro- cesses for each ray. These processes give off secondary branches at right angles to them- selves, and the latter end in tertiary caeca. In Coma tula the caeca disappear, and the canal acquires a distinct mouth and anus, which open near each other. In all, the canal is muscular, is enclosed in a ciliated peritoneum, and has its primary divisions attached by a kind of mesentery. In the Echinus, the anus generally opens on the upper or opposite surface of the body. Many of this genus have a complex masti- catory organ, which is acted upon by powerful muscles. The first part of the canal opens into an intestine of much larger diameter, opposite to a blind dilatation very like the human caecum. The intestine is coiled twice around the inner surface of the shell ; the second coil reversing the direction taken by the first, and both exhibiting a sinuous course. Its width tapers away to the anus. Its struc- ture is delicate and transparent; it possesses a mucous membrane, and longitudinal and trans- verse fibres ; and it exhibits an intestinal vein, which is especially marked towards the termi- nation of the canal. In the vermiform Holothimee the canal forms a kind of Z in the abdominal cavity; — passing first backwards, then forwards, and again backwards to its posterior extremity. The first part is wider and stronger than the rest, and its more glandular mucous membrane presents longitudinal folds which terminate in a slight circular one. Such a structure causes this dilatation to be regarded as a stomach. The narrowing intestine often ter- minates in a large oval cloaca, into which open two branching caeca.* The Annelida form a class of animals so diverse in nature and structure, that it is diffi- cult to include all the varieties of their diges- tive apparatus within a mere brief sketch. The canal always possesses a distinct mouth and anus, which occupy the opposite ends of the more or less elongated and cylindrical body. Prehension is generally aided by teeth, which, as in the Leech, perforate the skin of their prey; while in others — as in some of the Errantes — it is effected solely by a proboscis. In many of the marine Errantes the intes- tinal canal is simple. In the Lumbrici the canal soon dilates into a membranous pouch, which is followed by a thicker and more muscular portion, supposed to be a gizzard. In some genera, this part of the tube is com- plicated by being produced into pouches. These are either numerous, as in the Leech; or few, as in some kindred genera. Fi- nally, in the Earth-worm, they are reduced to mere constrictions of the canal ; while in the Aphrodita, they are developed into tubes, which expand, divide, and terminate as al- most globular pouches. Clusters of glandular follicles, which are supposed to be biliary, open into the posterior half of the complicated canal of the leech just alluded to : and analo- gous structures are found in other genera. In the Earth-worm, there is a singular ap- paratus, the typhhtote. This is a blind tube, which occupies almost the whole length of the canal, being attached to its dorsal aspect, and * Such a complex organization is strangely con- trasted with the alleged fact, thai the animal, when alarmed, can shed the -whole canal. This extraor- dinary act is presumed to be voluntary, and is only paralleled by the growth of another digestive ap"- paratus, which replaces that evacuated. 298 STOMACH AND INTESTINE. projecting into its cavity. Its interior surface is folded and villous. The whole structure appears to be connected with a kind of chy- lous absorption. The alimentary canal of the Epizoa differs from that of the cavitary Entozaa, in being generally surrounded by a glandular mass, the function of which is probably hepatic. The Cirripeda have prehensile jaws, and a ter- minal mouth and anus. In some, the canal has a gastric dilatation. Hepatic follicles, similar to those already described, occur here also. And St. Ange and Serres have found a tube analogous to the typhlosole. The digestive tube of the Crustacea may be reduced to two chief forms, which corre- spond with other differences in the nature and structure of their possessors. Thus in those lower Crustaceans which are suctorial and para- sitic, the canal is a very simple one. A proboscis conceals a pair of lancet teeth, and is followed by a straight intestine, around which are clustered a dense mass of follicles, supposed to constitute a liver. The higher Crustaceans possess a complicated apparatus of forceps and jaws. A short oesophagus leads to a large spherical cavity, which occupies the head of the animal, and which, although sometimes called a stomach, contains hard structures that render it analogous to a gizzard. A well- marked constriction separates this organ from the intestine, which is sometimes simple and nearly straight, sometimes divided into two portions distinguished by a projecting valve. The liver is conglomerate, and divided into lobules. Rarely, one or two caecal tubes are also present. The alimentary canal of the Insect offers what are rather varieties of development than any regular transition, such as we have remarked in some of the preceding orders: — varieties which the metamorphosis of the larva at present seems to complicate instead of ex- plain. In the larva, the canal is comparatively simple, and somewhat approaches the condi- tion seen in the lower Annelida : being a straight tube, with a mouth and anus at opposite ends of the body. In many Hymenopterous larvae, the latter aperture is absent, In others it is only developed towards the end of this stage of life, when an excrement — or meconium as we may perhaps call it — is for the first time expelled. But though such an intestine might seem to resemble that of the anen- terous Infusory, or the hydriform Polyp, we must recollect that it differs from these in the important fact of its not being used for the double purpose of ingestion and egestion. The complications of the above simple canal relate chiefly to its subdivision, and to the addi- tion of blind tubes. A gastric dilatation is the first to appear ; its extremities then become constricted, and its calibre enlarged. An oeso- phagus, a crop or ingluvies, a small and a large intestine, may also be added. Sometimes the supposed stomach is transversely divided into two cavities, and complicated by short caeca. In other instances, longer tubes open into the same part of the canal. While in others, they open into the intestine below this point; and are hence presumed to be biliary. In the perfect Insect the varieties of form are still more numerous and perplexing. Besides the complicated prehensile and dental apparatus, there is often an oesophagus, a crop, a muscular gizzard, a stomach, a small intestine, a large intestine, and a narrower rectum. But development is manifested, not only by differ- ences in the diameter and structure of dif- ferent lengths of the tube itself, but also by its complication, through the addition of supple- mentary organs of a more or less tubular form. The ingluvies or crop is present in many but not all of the suctorial genera. It is sometimes distinctly glandular. And even where, as in the Bee, this character is less prominent, it is still probably a secreting organ. But its uses seem to be mainly those of accu- mulation. The gizzard is generally added to the former organ. It is characterized by distinct mus- cularity, and a more or less hard or horny epithelium, which is often developed into plates, protuberances, hairs, or teeth. Some- times it is only rudimentary: — a toothed oesophagus subserving its functions in some insects ; while in others, it is reduced to a mere thickening of the muscular wall of this part of the canal. The stomach is also of various form and size. In some insects it is simple ; in others it is more or less plicated or cellulated, or its cells are even prolonged into short caeca. The peculiarities of the remaining subdivi- sions of the canal are chiefly those of their length and width, and in the degrees of con- striction by which they are separated from each other. As yet, however, it has been found im- possible to make out any intimate connection between these differences in the anatomy of the tube and the habits of the animal possess- ing it. Indeed, the general relations of this kind seen in other orders often seem to be interrupted or even reversed in the insects. The numerous tubes which open into the intestinal canal present still more diver- sity. They are often named salivary, biliary, or urinary organs. Thus those tubes which open into the earlier part of the intestinal cavity are called salivary ; those which empty themselves into the commencement of the small intestine are regarded as biliary; and, finally, those which open into the canal at or near its termination, are considered urinary. It is only the first of these that, after many grada- tions, fairly attain the glandular development which a conglomerate condition implies. The second vary chiefly in number, and in the fre- quency of their anastomosis. The third are rarely vesicular in shape. The digestive canal of the Arachnida offers, on the whole, more uniformity. The chief divisions of this order are the parasitic, the spiders, and the scorpions. All are " carni- vorous :" — a term which here, as often else- where, is only approximative^ correct; since most of them do not devour the flesh, but STOMACH AND INTESTINE. 299 rather suck the juices, of their casual or more permanent victims. Tne simple digestive tube of the Acari or Mites is prolonged in a straight line from mouth to anus. It is sometimes complicated by gastric caeca or dilatations. In the Aranei, or spiders proper, a~ slender oesophagus passes back from the mouth to a " stomach." Tiiis is sometimes a mere dila- tation; sometimes is indicated by four sacculi, that radiate from a narrow tube; and sometimes presents a cavity, having blind prolongations that extend into the bases of each of the maxillary palpi and thoracic legs. All these parts occupy the anterior Or cephalo-thoracic division of the body. The remainder of the canal, entering the abdominal segment, dilates, after a single convolution, into a large and sometimes globular intestine, to reach the anus by a short portion, of narrower diameter, called a rectum. The long tubes met with in the Insects recur in this order. One set, of vary- ing size, open in the neighbourhood of the complicated apparatus of prehension ; these, from their position, are supposed to be sali- vary. And occasionally a special poison gland appears to empty itself in this neigh- bourhood. A middle set, called hepatic, often forms two pairs of tubes, with orifices much posterior to the gastric sacculi ; in other cases they are very numerous, and are con- cealed by a granular mass, which occupies the same situation. The posterior set are one or two pairs of long cseca, which join the intestinal cavity close to its termination, and are hence compared to urinary organs. The Scorpions have a tolerably straight, narrow, and simple tube, complicated by several pairs of straight sacs, which come off at right angles to its anterior part, and are probably gastric crops. Below these, two bifurcating tubes, of great length and small diameter, open into a constriction of the canal. They are regarded as hepatic. In the order of MoUmgca, many of whom in- habit the sea, we may again trace a gradual ad- vance of development in the intestinal canal. The Tumcata is its lowest subdivision. Here a simple canal begins by a wride oeso- phagus, that leads from the bottom of the branchial sac to a stomach or dilatation. This is surrounded by a number of hepatic follicles, that open into its intestinal end ; and it leads to a wide recurved intestine, which ends by an aperture on the upper and outer surface of the animal. Sometimes the liver varies from this description in the fact that its follicles are aggregated. The Brachiopoda possess a digestive ap- paratus of nearly equal simplicity with the preceding. Dental structures are wanting ; and the liver is still follicular. The LameUibranch'uita exhibit a somewhat similar condition. Their gastric cavity is sometimes preceded by a short oesophagus. From hence a comparatively simple intestine continues, with a few convolutions, through a mass of liver, to terminate, by a long straight portion, in the anus. The latter segment, or rectum, lies along the hinge of their shell, and often perforates the heart in its course. Al- though the liver is large and aggregate, it opens by several ducts into the gastric dila- tation.* The Gasteropoda have a head, jaws, and salivary follicles. Their longer oesophagus sometimes dilates into an ingluvies or crop. Their stomach often possesses a thickened lining, and a masticatory apparatus of teeth or plates, which make it a kind of gizzard. Sometimes it is divided into two or more compartments. The large liver opens into the pyloric extremity of the stomach, or the com- mencement of the intestine, by one or more ducts; or, rarely, it empties itself into the oesophagus. One or two large glandular caeca also open into the beginning of the intestine, and are regarded as a rudimentary pancreas. The remainder of the tube is simple, and ends anteriorly in the body, in accordance with the general structure of the animal. In the numerous herbivorous species, the intes- tine is longer and more tortuous ; while the crop, the gizzard, and the masticatory appa- ratus all reach a high development. The intestinal canal of the Pteropoda is very similar. It possesses jaws and salivary glands, together with an oesophagus, a crop, a gizzard, a short and simple intestine, and a conglo- merate liver that often opens by a single duct. The Cephalopoda exhibit a marked advance of development. Their mandibles form a powerful organ of mastication ; and, in many species, salivary glands co-exist. The mouth leads to a long and dilatable oesophagus, which descending, sometimes expands into a crop before it finally reaches the gizzard or muscular stomach. This organ is of tolerably uniform appearance. Its shape is round, or somewhat elongated ; it has a thick and whitish epithelial lining, and its muscular layer consists of two sets of fibres, each of which radiates from a central tendon on one side of the organ. The cardiac and pylo- ric orifices are situated at its upper part. The intestine coming from the latter soon communicates with another cavity, which is sometimes regarded as a stomach. This is, in the lower Cephalopods, nearly spherical. But in many of the higher or Dibranchiate division, it is of less simple form, being triangular, elongated, or folded spirally like a snail shell. Its mucous membrane is rugous and follicular ; and the large liver, which is still supplied by arterial blood, opens into it by a single duct. The intestine continues hence as an uniform tube, which, after one or two slight curves, bends upwards to open at the base of the funnel. In some species we also find caeca! appendages, the ducts of which join those of the liver before they enter the * In some species a curious style or hard conical process occupies a tube of similar shape, that com- municates with the gastric dilatatiou. The use of this implement is unknown ; but it has been sug- gested to effect a triturative process : — a supposition which, if true, would render the cavity containing it the analogue of a gizzard. 300 STOMACH AND INTESTINE. intestinal cavity. These have been supposed to constitute a rudimentary pancreas.* The alimentary canal of Fishes is simple, wide, and short, compared with that of other Vertebrata. Its chief subdivisions are an (Esophagus, a stomach, and an intestine. The oesophagus is large, dilatable, and mus- cular. Its mucous membrane is generally simple, sometimes involuted or glandular ; and offers a remarkable contrast to the redder and more vascular membrane of the stomach at the point of their junction. As the dia- meter of the tube rarely undergoes any great and sudden increase in this situation the above contrast of structure is often the only distinc- tion between the two cavities. The stomach varies greatly in size and shape. Usually, however, it forms a curved tube like a siphon. The obliteration of the concave side of this tube converts it, by many gradations in different genera, into the shape of a two-necked flask, or of a blind tube with a double orifice at one end. In other instances it is dilated, or almost globular. Where tubu- lar, it generally tapers away towards the pylo- rus. And this end of the stomach, which is usually more muscular than the cardiac, some- times approaches the structure of a gizzard, having constricted extremities, a thick muscu- lar coat, and a scaly epithelium on its mucous membrane. The valve itself is almost always present, as a circular ridge of muscular fibre, covered by a fold of mucous membrane. The intestine of the fish is short and wide : and generally consists of two portions, which are separated from each other by a slight con- striction into a small and large intestine. The first receives the bile-duct, and the follicles which form the rudimentary pancreas. The latter also occasionally receives a caecal tube. The intestine has the usual three coats — serous, muscular, and mucous. The serous membrane is often pigmentary, and its cavity communicates by apertures with the exterior. It rarely forms a continuous mesentery ; — the attachment of the intestine being generally ligamentous or filamentous, or even, as in one instance f, by means of a mass of areolar tissue that involves the whole tube. The muscular coat is of unstriped fibres J, which form two layers, the circular generally ex- ternal.^ The mucous membrane is variously folded : it sometimes contains ductless glands : rarely it is ciliated. || The chief deviations from these the ordinary characters of the intestine * Many anatomists, however, consider the office of this gland to be fulfilled by the cavity previously mentioned. But strong arguments against this view might be derived from the development of glands in general, and of the pancreas in particular ; both in the phases of individual life, and in the advance of the animal series. In addition to this, the gastric character of this cavity, and the unfitness of a giz- zard for solvent or digestive functions, further justify us in preferring the above interpretation. t The Tetrodon mola. + In the Tench (Cyprinus tinea), they are striped. § Reversing their ordinary arrangement in the Mammalia. || As in the Branchiosfoma. are, either an increase of length, which is some- times accompanied by a diminution in width ; or an equally real increase of active surface, which is due to the development of folds, such as the spiral valve of the Shark. The appendices pyloricce, or pancreatic follicles, are absent in many fishes. They vary in number from one to two hundred. In structure they range from simple, short canals, to elaborate branches, which are united by areolar tissue and vessels, and are enclosed in a muscular tunic. The alimentary canal of Reptiles preserves much of the simplicity, width, and shortness, seen in that of Fishes. But it offers important differences in many respects. The thick, semi-transparent, gelatinous-looking intes- tinal parietes generally possessed by the Fish, are strongly contrasted with the thinner and more condensed and opaque tube present in the Reptile. Such a comparison seems to indicate a great advance in the develop- ment of the Reptilian digestive canal. This advance, though no doubt correlative with that of the tissues generally, probably depends chiefly on the increased efficiency of the respi- ratory function. The (esophagus varies greatly in size and appearance. It is usually large and dilatable. In the Ophidians this width and laxity are so greatly increased, that it forms a tube which can be distended to almost any extent ; and the parietes of which are so thin, that they may be regarded as supplanted by the muscular parietes of the belly itself. The stomach rarely possesses any well-marked cardiac constriction. Hence the characters of its mucous membrane are the chief means by which it can be distinguished from the oeso- phagus. Its form, in the Chelonian and Ba- trachian divisions, somewhat resembles that seen in many fishes. Beginning by a dilated cardiac pouch, it tapers away towards the py- lorus, taking a curve like a siphon. In the Crocodiles, the stomach may be regarded as consisting of two portions. Of these, the first is a gizzard : which resembles the form and appearance of that of the Cuttle-fish ; and con- sists, like it, of a plane of muscular fibres, that radiate from a central tendon on each side of the organ. The second is a small pyloric pouch or diverticulum, which passes out of the gizzard at its upper part, close to where it receives the dilated oesophagus. In many Serpents the pyloric extremity is so narrow and muscular, that the organ has been distin- guished into two parts : — an upper, or cardiac, which is thin and saccular ; and a lower, or pyloric, which is narrow, strong, and tubular. The pyloric valve varies in development. But even where best marked, it never approaches the distinctness seen in man and the higher Mammalia. It consists, as usual, of a pro- jection, which is formed by the circular muscular fibres, and is covered by a fold of mucous membrane. The intestine is short, and rather wide. It is usually divided into small and large by a circular constriction or valve. STOMACH AND INTESTINE. 301 In the Batrachian division, however, the separation into these two segments is some- times absent, ^^^hile sometimes, as in the Toad and Frog, there is a distinct large intestine, into which the smaller portion opens laterally, so as to form a caecum. In the former of these two genera there is no valve. In the Ophidian the two portions are generally distinct and short. But their relative extent varies considerably : the small intes- tine being sometimes lengthened, and often presenting a very peculiar appearance in the shortness of its mesentery and the closeness of its folds. The indistinct ilio-caecal valve is chiefly marked by a change in the diameter of the tube. The large intestine is often sub- divided into distinct portions by one or two transverse valves. In the Chelonia the intestine is longer and much more muscular. There is generally an ilio-caecal valve, and often a well-marked cxcum. The valve is also present in most of the Sauria. But in the Crocodile the cae- cum is absent. Birds. — In this class, the stomach is generally complex; being separated into three distinct cavities, which differ greatly in their form, structure, and office. The oesophagus, which leads to the first of those cavities, has a length corresponding to that of the neck which it occupies. Its width and dilatability mainly depend on the nature and form of the food. Thus, in some of the birds of prey, or those which swallow large fish entire, it is very lax and dilatable. And in this respect, as well as in the direct con- tinuity of its cavity with that of the stomach, it offers a great similarity to the gullet of the Ophidian reptiles and many fishes. Its mucous membrane is follicular, and folded longitudinally. The ingluvies, or crop, is a dilatation of the oesophagus, somewhere about the middle of its length. In some of the smaller Rap- tores it is but small ; in the larger and more voracious it is a considerable enlargement, that affects one side of the tube more than the other ; in the Gallinaceans it is a distinct sac, appended to the canal by a narrower neck ; and, finally, in the Pigeons, it attains its maximum size, and becomes double. Its muscular and mucous membrane are similar to those of the oesophagus. The food which it contains undergoes a kind of insalivation and maceration. And the highly-developed form of crop, which is seen in the Pigeon, pours out a milky fluid during that period of the year in which this bird feeds its young by regurgitation. At this time its mucous membrane also acquires a thicker and more glandular character. The proper stomach, or proventriculus, com- municates with the inferior part of the oeso- phagus, and corres'ponds, both in structurelmd function, with the true stomach of the Jfani- malia. The glandular tubes which open on its free surface secrete a fluid that possesses all the properties of gastric juice. In the degree of complication these glands differ considerably ; varying from simple tubes in the carnivorous birds, to tubes that open between prominences and prolongations, and finally form primary and secondary branches. The shape and size of this organ are subject to great variety in different genera. In those that swallow a large prey, it is wide and straight, like the stomach of the Serpent. In others, it ap- proaches the spherical form, or passes towards the right side to join the gizzard. The com- parative size of these two organs also varies considerably. The gizzard is a flattened ovoid of highly muscular texture. It is lined by a dense horny cuticle, and contains sand, gravel, or other hard inorganized matters, which are the passive agents in the trituration of the food. Its size varies greatly. Its apertures both occupy the upper part of the organ, so thai its cavity terminates below in a blind ex- tremity. Its walls contain a variable amount of muscle, the arrangement of which is usually that of the radiation of fibres from a central tendon, such as was previously noticed in speaking of the Cephalopoda. Its epithelium is hardest in the granivorous birds. And even in the same individual, it offers an increased density at the precise situations of most pressure. In like manner, Hunter noticed that a thickening, both of cuticle and muscle, was produced by feeding a Sea-gull upon grain. The pyloric valve is, as a rule, well marked. In some species there is a small supplementary cavity, which immediately precedes it, and receives the orifice of the gizzard. The intestine has a length about midway between that of the Reptilian and Mammalian bowel. But although longer than in either of the preceding classes, it retains considerable simplicity of form. It presents, however, much variety, both in its length and in the number and appearance of its convolutions ; — differences which, as usual, are related (though not very closely) to the food and habits of the animal. The duodenum which immediately follows the pylorus has the form of a long loop or fold, the concavity of which includes the pancreas. The small intestine, more or less folded, terminates in a large intestine, the commencement of which receives two caecal tubes, one on each side. These caeca offer remarkable differences in length : — vary ing from papilliform offsets, as in the Solan-goose, to processes three feet long, as in the Grouse. Sometimes only one is present. The short and straight large intestine is continued from the termination of the small intestine, without any distinct valve, to end in a cloaca com- mon to the digestive, urinary, and generative organs. Connected with the small intestine is an appendage, supposed to be a relic of the duct of communication between the yolk bag and intestine of the chick. It is de- void of a muscular tunic, and in some birds equals or exceeds the size of the caeca them- selves., Mammalia. — The form, length, and arrange- ment of the alimentary canal vary so much in the different orders of Mammalia, that it 302 STOMACH AND INTESTINE. will be necessary briefly to state its pecu- liarities in each. In the Canrivora the shape of the stomach approaches that of the human organ : it has a cardiac pouch, and a greater and lesser curvature. The intestine is short, its length being to that of the body as* 5 to 1 in cats and dogs, and 8 or 9 to 1 in the hyaena and bear, but reaching 15 to 1 in the Phoca vitalina, one of the amphibious seals. The mucous membrane is destitute of folds. The convolutions of the small intestine are few and simple. The caecum is short, and scarcely wider than the rest of the large intestine.f And the latter segment of the canal is short, wide, and cylindrical. The Insectivora have a very similar intestinal tube. The simple and elongated stomach is transverse to the axis of the body. In some genera, its spherical cardiac pouch is enlarged, while its lesser curvature becomes shortened. The intestine is short — from three to six times the length of the body ; it has no caecum, and a nearly uniform diameter. Its mucous membrane exhibits zig-zag folds, which run longitudinally throughout its whole length. In the Cheiroptera three chief varieties of stomach have been distinguished by Cuvier. The first approaches that seen in the preceding order, and belongs to those members of this group which feed upon insects. Here the nearly spherical organ has a cardia and pylorus, which are situated close to each other. The second form is seen in those which subsist by sucking the blood of animals : it differs from the preceding in being longer, and more conical from cardia to pylorus. The third, which obtains in the frugivorous division, is very different from both the pre- ceding. Thus, in the Pteropus the stomach is a long tube, placed transversely to the axis of the body. One-third of its length is formed by the cardiac pouch, which lies to the left of the cesophageal aperture, and is divided into two bv a slight constriction, while its terminal or pyloric third is bent back so as to be parallel and near to the middle portion. The mucous membrane of this stomach is folded longitudinally ; the left subdivision of the cardia is smooth, and the lower part of the oesophagus — which is somewhat dilated — differs from the upper. The pylorus is well marked in all the Cheiroptera, and the intestine, which is much narrower than the stomach, and is devoid of caecum, is of nearly uniform diameter. It often presents concentric windings or coils. Its length varies greatly ; — thus, in the frugi- vorous Pteropus it is six or seven times, in the insectivorous Bat only twice, the length of the body. Edentata. — The stomach of this order differs greatly in different genera. Most of them possess a simple organ ; the cardiac * We owe these measurements to Meckel. •j- In the dog it is convoluted. pouch of which is large and globular, while the pyloric extremity is conical, and is some- times almost absorbed into the spherical cavity. A single genus, the Mains, adds a further distinction to these two parts in the shape of an internal fold of mucous mem- brane ; and one of its species exhibits a long blind sac, springing from the right of the pyloric aperture. In the Tardigrade genera the stomach assumes much of the complexity seen in the Ruminantia. For it has two cavities, a cariliac and a pyloric, which, if regarded from the exterior, look like mere exaggera- tions of the distinction mentioned above, but, when examined internally, are seen to be divided by prominent folds, and by differences in the character of their mucous membrane. Thus the cardiac pouch has a dry epidermoid lining, and is subdivided by a fold into two parts, and prolonged into a short blind tube, while the pyloric sac has a soft and delicate mu- cous membrane, and more muscular parietes. And its interior is also subdivided, by a fold of membrane, into a terminal part, which is analogous to the fourth stomach of the Ru- minants, and an intermediate cavity, which resembles the third stomach of the same order in its possessing dentate processes, and a direct communication with the oesophagus. The latter tube also exhibits a cul-de-sac, which is sometimes further divided by folds. The form and length of the remainder of the canal is subject to great variety. Its mesentery is very long. In many genera there is no distinction of the intestine into large and small. In some there is no trace of a caecum. In others there are two of these tubes, which occupy the confines of the lanje and small intestines, and open by what are sometimes extremely minute apertures.* The Ruminantia are remarkable for the com- plete subdivision of their stomach into four dis- tinct cavities. The first of these, the rumen, or paunch, is generally of very great size. It is situated to the left of the oesophagus, from which it receives the food when first swallowed : it has a villous texture, but its minute conical processes are covered by a dense white pave- ment epithelium. The second cavity, the honeycomb or reticulum, is so called from the appearance of its mucous membrane, which, in all other respects, has the same structure as that of the preceding cavity. The third portion, the maniplics or psalterium, is named from the many longitudinal plies or folds which occupy its interior. In the Camel, the circumference of the cells or excavations of its reticulum and paunch have been long recognized as containing muscular fasciculi, the contraction of which enables these cavi- ties to retain water free from admixture with the general contents of the stomach. And * In such a case they can hardly be supposed to receive faecal matter. But in the Dasypus muste- linus, the ileum ends by a slit between the larger apertures of two such tubes ; and hence appears to admit of being closed by the lateral pressure of their contents. (See Prof. Owen's Catalogue of the Hun- teriau Museum, vol. i. p. 219. 729 A.) STOMACH AND INTESTINE. 303 eight or nine years ago, the author discovered that all these projections from the surface of the ordinary Ruminant stomach, — viz. thevilli, honeycombs, and plies — are constructed chiefly of unstriped muscular tissue, lined by scaly epithelium. The uses of such a structure are too obvious to need any comment. The fourth cavity or abomasum, is the true stomach : it secretes* the gastric juice, and possesses the ordinary tubular structure. As regards the uses of these cavities, the bolus is probably- moulded for rumination in the honeycomb, and is thence regurgitated into the gullet ; while a muscular fold forms a direct pathway for the ruminated food to pass at ouce from the oesophagus to the maniplies. Pachydennata. — The Elephant has a stomach which is elongated, and subdivided by very numerous folds. In other respects it is simple. That of the Rhinoceros is similar ; but the cardiac pouch is devoid of folds. The shorter stomach of the Pig is divided internally by two folds of mucous membrane into three por- tions : — a cardiac pouch, a pyloric extremitj-, and an intermediate portion, which receives the cesopliagus. The lesser curvature, and the back of the cardiac pouch, are both occu- pied by a white and dense epithelium, which is similar to that of the oesophagus, and forms a broad quadrilateral band along this aspect of the interior. In the Pecari there are ex- ternal indications of the same subdivisions : but the white epithelium extends over a wider surface; so that it is only the pyloric third, and the lower parts of the middle and cardiac pouches, which exhibit the proper gastric or tubular structure. In the Hippopo- tamus, the stomach is long and tubular, and is complicated by the addition of two pouches, which have a size almost equal to its own, and communicate with its cavity by corre- sponding orifices on the right of the oesophagus and at the back of the cardia. The internal surface of the organ is so folded as to allow the alimentary bolus to enter either of these two cavities.* Tne stomach of the Solipeda has a rounded shape, and a cardia and pylorus which are close to each other. The cardiac half of the organ is lined by a white epidermis, which terminates by an abrupt dentated margin. " In all these three orders — Ruminants, Pachyderms, and Solipeds — the intestine is characterized by great length, width, and convolution, and by the possession of a capa- cious caecum. Thus, in the Ruminant sheep, the intestine is thirty times the length of the body. And although in the Soliped horse this proportion sinks to fifteen or twenty, still the * The above is a description of the organ in the foetal Hippopotamus, to which alone our present information refers. Cuvier suggests this to have been an incomplete development of a compound organ, akin to that of a ruminant : the stomach being the abomasum, and the diverticula represent- ing the paunch and honeycomb. But the tough and wrinkled character of the mucous membrane which lined the supposed abomasum in the greater part of its extent seerns to negative this view. sacculation of the caecum and colon which ob- tains in this and the Pachydermatous order per- haps compensates such a diminution in length. Theilio-caecal valve is represented by a narrow passage, the mucous membrane of which forms six or eight thick longitudinal folds. The caecum, smallest in the Pachyderm, attains its maximum size in the Soliped ; being, in the Horse, two feet long, and thrice as capacious as the stomach. In one Pachyderm — the Cape Hyrax — two additional c&ecal tubes open into the large intestine by wide apertures. In the Rodentia the stomach is separated by an external constriction into two portions: — a cardiac, clothed with a thick epidermis, and a pyloric, occupied by a mucous mem- brane which has the ordinary tubular struc- ture. The size of the former pouch varies in different genera ; the latter sometimes pre- sents an imperfect subdivision. The whole organ occasionally approaches a conical or spherical shape. In the Beaver and Muscar- din, the stomach is complicated by the addi- tion of glandular crypts and caeca, the im- port of which is unknown. The intestine of the Rodent is very long and convoluted, and the small and large intestine are of nearly equal diameter ; but the latter is deeply sac- culated. The caecum is usually very large, and is sometimes subdivided by spiral or cir- cular folds. But in the omnivorous Rat it is small ; and in the Dormouse it is altogether absent. Marsnpialia. — In a large proportion of this order, the stomach has a considerable resem- blance to that of the human subject. Such an organ is found in both carnivorous and herbivorous Mar»upialia : and indeed, it is difficult to point out any differences in its size or shape which are distinctly referrible to the habits of its possessors. In some, how- ever, a stomach oF very similar outside shape exhibits a lesser curvature, which is oc- cupied by a gastric gland like that of the Beaver, composed of numerous irregular crypts. In the Kangaroo (Mao-opus) both the shape and the structure of the organ differ widely from the preceding. The stomach is of a length which equals that of the whole body ; the cardiac pouch is subdivided into two caeca ; and the middle part of the organ is sacculated by three bands of longitudi- nal muscular fibres, so as closely to resem- ble the ordinary arrangement of the colon, — except that the interspace between the upper two, or that third of the surface which occu- pies the lesser curvature, is not sacculated. The gastric gland is broken up into numerous follicles, which are placed in three rows parallel to the longitudinal muscular bands. The mucous membrane of the oesophagus is continued right and left of the cardiac orifice for a considerable distance; some- what as in the stomach of the Pig. The re- mainder of the mucous membrane is of the ordinary soft character. The "intestine of the Marsupial is also sub- ject to great differences. The carnivorous members of the class are devoid of a caecum. 504 STOMACH AND INTESTINE. The insectivorous Marsupials have a longer intestinal canal, which is separated into large and small intestine, and exhibits a caecum of moderate size. Those that live upon fruits have bowels which are still longer, and a large caecum of twice the length of the whole body. Finally, the true vegetivorous genera have a caecum which is thrice as long as the body. In those which are possessed of a saccu- lated stomach, the caecum is, however, much shorter. One genus, the Wombat, has a vermiform appendix. The length of the whole intestine varies from two to ten times the length of the animal. In the Monotremata the alimentary canal is chiefly remarkable from its terminating in a cloaca common to it and the urinary and generative organs. A small caecum separates the long and narrow bowel into two parts. The diameter of the small intestine gradually diminishes to the caecum, while that of the large intestine gradually increases to the rec- tum. The Cetacea offer two chief varieties of stomach, which are connected with differences in their food, though scarcely explained by them. Those which live on vegetable food exhibit a simpler form of organ. Thus, in the Dugong, the stomach is long and transverse ; and is divided by a deep constriction into a globular cardiac, and a conical pyloric, portion. Two large caeca open into it near this con- striction ; and a special glandular apparatus occupies the upper part of the cardiac pouch. In the carnivorous Cetaceans, the stomach is subdivided into three, five, seven, or more cavi- ties. In some genera, however, there are only four. Of these the first has an epidermoid lining, while the three last have a soft mucous membrane. The biliary duct often opens into a dilated cavity, the import of which is unknown. The intestine is longer in the herbivorous di- vision. Here there is also a caecum ; which is sometimes large and glandular, but some- times small, short, and even bifid. In the zoophagous Cetaceans there is rarely either caecum or valve: — so that the intestine, which decreases slightly in size from the pylorus to the anus, offers no separation into large and small. But in the genus Batcena there is a small caecum, like that of the Cat. The Qnadrnmana possess a stomach the form of which approaches that of the human organ. In some cases, however, it is more elongated ; while in others it assumes a glo- bular shape, with a cardia and pylorus in close proximity. The latter deviation is generally found in conjunction with carnivorous or insectivorous habits. It is usually separated into two portions, a cardiac and a pyloric ; and sometimes the latter, which is more globular than usual, is distinguished by an internal fold from a short tubular part, which termi- nates in the pyloric valve and the duodenum. Rudimentary pyloric ca3ca have been remarked by Cuvier * in one instance. The Sem- nopithecus presents a form of stomach which * Lemons d'Anat. Comp. vol. iv. p. 28. recalls that of the Kangaroo. For the cardiac cavity, smooth and almost bifid at its com- mencement, is soon sacculated by a superior and inferior band of longitudinal fibres which come from the oesophagus ; and from thence the sto- mach continues to the right side, as a saccu- lated tube, which is bent upon itself, and closely resembles a large intestine. But before reach- ing the pylorus, these sacculi diminish and dis- appear. The length of the intestinal canal in the different genera of this order varies to an extent which is curiously contrasted with the general similarity of their food. Its proportion to the length of the body is in some as 8 to 1 ; in others as 3 to 1 only. The division into two portions, and the general arrangement of both small and large intestine, is very similar to that seen in man. In all the genera a caecum exists, but with great variety as to length : — an increased development of this portion of intes- tine, as well as of the cardiac extremity of the stomach, being sometimes connected with a diminution in the length of the whole canal. The Apes and Gibbons possess a vermiform appendix ; but in the latter it is of very small size. The mucous membrane has villi, but no valvulas conniventes. General remarks. — Althougii physiology at present scarcely pretends to interpret'this various and complex development of the ali- mentary canal, still some attempt at its expla- nation is indispensable. For without any clue to their import, details like the preceding could hardly be recollected, far less made use of; and would scarcely deserve to be stored up in the archives of science, much more brought forward in an essay like this. Nor, in attempting their explanation, can one be rightly charged with breaking those rules which our great countryman has laid down for the pursuit of natural knowledge. All that is necessary to such a superstructure of theory is, that, how- ever slight and temporary, it should at least be founded on the known facts ; that it should in- dicate something like the degree of probability assignable to its several parts; and, finally, that it should be at once yielded up, as soon as a stricter logic, or larger and more numerous facts, offer us a better explanation. The absence of all digestive cavity is the first peculiarity which demands our notice. The few genera in whom this rare condition has been found all offer the greatest simplicity of structure; and further agree in the fact that they are parasitic : — i. e. that they derive their nutriment from the juices of another animal, to whose body they are attached. Hence we need not scruple to assign this apparent defi- ciency of the digestive organ, partly to the pre- vious elaboration of a highly nutritious animal food, partly to the simplicity of the various tissues which are destined to be nouiished by it. But can we therefore say, that the function of digestion is absent, or — what would be nearly equivalent to such an assertion — that it is reduced to a mere physical absorption ? Probably not. For, as regards the general de- velopment of the animal series, comparative STOMACH AND INTESTINE. 305 anatomy conclusively shows that the fusion of certain structures by no means implies the absence of their several functions ; while a history of the development of each individual would equally establish that, though the embryo at a certain stage of life is quite devoid of a digestive cavity, it is nevertheless nourished by materials which have been pre- viously set apart from the substance of the parent. And just as it must doubtless effect some change in these materials, in order to assimilate them to its own various textures, so it is evident that such a change, however slight, probably represents what is as much a digestive as an absorptive act: — a digestion in which the absence of many of the ordinary agents is sufficiently accounted for by the mini- mum of waste which this food supplies, and the minimum of change which it has to undergo. Now some of these parasitic genera are also con- nected by the circumstance, that the anenterous condition probably forms but a stage of their development ; — so that the process of time, or their transplantation to a more congenial dwelling, would often convert them into animals possessing an alimentary canal. Of such creatures we might therefore vaguely say, that they retain the low digestive development of an early ovum; or, in other words, that they are themselves the partially developed embryos of a very simple organization. That, with such a simple structure, they should effect such a complex function, is surely not one whit more extraordinary than what appears to be the case in the action of every ordinary cell ; which is what it is — liver, kidney, or the like — by virtue of powers that its mere structure will not explain — powers that enable it to attract and retain certain materials, to re- linquish or dismiss others, or even to effect a definite metamorphosis in its own chemical ingredients. The simplest form of the digestive organ may be seen in the hydriform Polyp, as a cavity of the body, in which the food undergoes a kind* of solution. The agent of this process is doubtless a fluid which exsudes from the mem- branous walls of the cavity. But as these are also the parietes of the body, it is to the latter that we must probably refer the origin of the solvent. That harmless inversion of the whole animal, which Trembley was able to effect, strengthens such a conjecture. Nor is it impos- sible, that the poison of the tentacles is itself but a more concentrated form of the gas- tric fluid. In any case, one cannot avoid suspecting that, in this animal, the alimentary solvent has some very simple chemical rela- tion to the organism generally. The more so that, although it acts upon the swallowed prey with the greatest energy and rapidity, the tentacles of the animal itself, which are often closely entwined around the hapless victim, are quite unaffected by even a prolonged stay * For the sense in which we are to understand the word solution as applied to this process, see the remarks upon the action of the gastric juice at p. 337. Supp. in the stomach. And the same impunity ex- tends to another animal of its own species which may have been swallowed while tena- ciously clinging round the prize * that both are disputing. It is usual to call such a simple digestive cavity a "stomach." But though the etymo- logy of the term quite allows of its being thus applied, still the definite character of this organ in the higher animals seems to sug- gest that we should either restrict its applica- tion, or recollect the doubtful meaning which it acquires by such an extended use. When- ever an organ of this kind appears to effect the solution of substances which pertain to the albuminous groupf, it is entitled to rank as a true stomach. But in proportion as this fact is uncertain or improbable, the name becomes a vague designation, which ought never to be made use of without recollecting what it really means — a mere receptacle of food. In the instances before us, such a receptacle probably represents, not only the stomach of the higher animal, but a fusion of this with the succeeding J portions of the tube, and with all the accessory organs of digestion, — such as the liver, pancreas, &c. And just as such simple cavities import more than a mere gastric function, so conversely we might find others bearing the same name, which com- plicate a fully developed alimentary canal, and thus imply less. These, though called stomachs, are probably mere crops. A complex digestive organ might at first sight seem to be the natural antithesis of the preceding. But though complexity forms a useful subjective contrast, without which we could indeed hardly conceive of simplicity — still, as already hinted, instead of a progressive evolution, corresponding to a gradual and suc- cessive advance of development, the alimentary canal rather offers a variety of deviations. And most of these deviations appear to result from causes, the number and intricacy of which is such as to defy all analysis. We shall therefore only enumerate those, the influence of which seems to be most direct and im- portant. 1. It is scarcely necessary for us to dwell upon that advance of development, and gradual increase of complexity, which the reader must have observed in the preceding sketch. He has seen how, in progressing from the low- est Infusory to the highest Mammal, a simple excavation first became a membranous canal ; how it then acquired an additional orifice; an organ of mastication ; a salivary appa- ratus ; a stomachal dilatation ; a subdivi- * It is interesting to notice that differences of development, such as are obviously almost tanta- mount to diversity of species, appear to remove all barrier to this solvent action. Thus the Polypiform Medusa devours and digests its Infusory-like younger brethren. t See p, 335. j The term " chylific stomach," sometimes made use of by comparative anatomists, seems especially to demand such a caution. For \ve need scarcely point out that, in the higher animals, at any rate, this organ does not "make chyle." 306 STOMACH AND INTESTINE. sion of intestine ; a liver ; a pancreas ; and, finally, a compound character of mucous membrane, by virtue of which the whole tube might be compared to one vast expanse or aggregation of glands. Some of these par- ticulars will again force themselves upon our attention. Hence we may here limit ourselves to the remark, that the main elements of this advance consist in the evolution or separation of accessories, and the increase and subdi- vision of surface: — and that both of these conditions imply a division of labour which, here as elsewhere, enhances both the quantity and quality of its product. 2. Respecting the homologies of the intes- tinal canal, scarcely anything can be said. As might be expected, form seems always subordinate to purpose: — in other words, neither general nor individual development offers us any permanent or temporary organs of digestion, from which we can deduce a shape that can be considered as a common pattern or archetype.* In rare instances, — as in the Earth-worm and Arachnidan, — the form of the internal canal approaches that of the body and limbs respectively. But even this peculiarity of form is probably teleological. 3. Sufficient allusion has already-)- been made to vegetative or irrelative repetition, as a pos- sible explanation of the complex canal seen in many of the lower Invertebrata. Some of these ramified canals — such as those of the Acalephae, and, with less probability, of the Distoma? — may be conjectured to represent a vascular, rather than intestinal, system. But there are others — such as those of the Leech and Spider — which seem to be true processes of the digestive canal, used as reservoirs of food. 4. Some complications seem mainly de- pendent upon circumstances which may be termed collateral or subordinate to digestion itself. Thus, the crops of many animals, like the cells of the Camel's stomach, are connected with the more or less necessary habit of gorging large quantities of food at distant intervals. While the gizzard, which is possessed by such very different orders as Polyps, Molluscs, Fishes, and Birds, appears to be closely related, not only to the food, but to the mechanical conditions of the animal. This is especially the case with the Bird, whose long neck, and habits of flight, could scarcely be rendered compatible with a heavy masticatory organ occupying the or- dinary position. 5. The import of some of those numerous blind tubes or pouches which we have so often noticed as opening into the intestinal canal, has already been suggested in the preceding remarks. They are generally, and * In this respect the intestinal canal may probably be contrasted with both the vascular and nervous systems. At least the author feels sure that the latter of these will ultimately be found reducible to that serial homology of the skeleton which the researches of Professor Owen have done so much to elucidate. t See p. 295. no doubt correctly, regarded as earlier developmental forms of the various conglo- merate glands which are appended to the canal in higher animals. But as regards the principles of their diagnosis, and the limits of its application, it seems important to remind the reader, that, in the present state of organic chemistry, the situation of their apertures, and the order of their appearance, often constitute our only guides. Thus, for in- stance, tubes which open into the commence- ment of the canal, especially in connection with a higher development of the masticatory organs, are probably salivary. In like man- ner, those which empty themselves in the neighbourhood of the pylorus are supposed to be biliary. And any which, by communi- cating with the anus and exterior of the body, appear to aim at an immediate and direct extrusion of their contents, naturally remind the physiologist of the highly poisonous characters of the urinary secretion, and so far entitle him to suspect that they serve to expel this important product of animal life. Here, however, chemistry would often assist his de- cision. The colour of the bile sometimes affords a less certain aid to the diagnosis of this secretion. The order of appearance only helps our conjectures by showing, that, of the two glands which open into the median por- tion of the digestive tube, the liver is the more constant and important:— and hence, that it is probable a solitary set of tubes are chiefly hepatic. But it is obvious that, in many in- stances, all these aids to conjecture may leave us in doubt as to the true nature of a set of secerning tubes. 6. In many of the Vertebrata — such as Birds and Edentata — there are caeca to which, as to the smaller vermiform appendix of man. the above explanation cannot apply ; since the ordinary accessory glands are also present. And some of the tubes seen in Insects are probably quite as supplementary. The struc- ture of all these tubes seems to indicate that they are true organs of secretion. But whe- ther this is their main function — or if so, what is the nature of their product — is utterly unknown. The supposition of their possess- ing a special absorptive function only increases this obscurity, by leaving it doubtful whether the lower parts of such tubes reclaim a por- tion of the secretion poured out by the upper —just as the intestine absorbs the bile after its entry into the duodenum — or whether they absorb materials derived from the general cavity of the intestine. But that increase of surface which facilitates mere absorption is effected by folds and projections so much better than by tubes, that, even supposing this latter re- absorption to obtain, we ought at least to concede some modifying power to the secret- ing surface. The ordinary situation of their apertures — near the junction of the small and large intestine — scarcely assists our spe- culations. It may, however, indicate an ex- posure of their secretions to the long and energetic absorption effected by the large in- testine. STOMACH AND INTESTINE. 307 7. Finally, we may close these vague con- jectures by attempting to include, in one for- mula, most of the varieties seen in the whole animal kingdom. The complexity of the di- gestive apparatus varies with that of the digestive function. And this is again the product of two chief elements : — the kind of food used; the nature of the animal to be nourished. In respect to the food, we might almost form a scale of decreasing simplicity, begin- ning with the rich chylous fluid that bathes the intestinal parasite, and passing through the various gradations of liquor sanguinis, blood, flesh more or less decomposed, vege- table juices, fruits, vegetables, and grains: — gradations which, however increased in number and minuteness, would all find their corresponding representatives in Natural His- tory. And we have already seen that, through- out the Vertebrate series, there is a constant association of a long intestine or a compli- cated stomach, with a vegetable diet. As regards the nature of the animal, the Acalephan, Crustacean, Cephalopod, Fish, Bird, Cetacean, all prey upon fish. Yet not only are their organs of digestion most di- verse, but they even exhibit a certain corre- spondence with the general development of each animal. Nor is it difficult to imagine why this is the case. Looking only at the unity of the organism, we might a priori expect, that a high development of the whole would imply an equal advance in the complexity of its chief parts. To this we may add, that one organ seems in a certain sense comple- mentary to another, — the necessary, and not merely the formal, result of an increased evolution of its fellow. And, in conclusion, it is not unlikely that the complexity of the digestive organ in the higher animals may be referred to causes even more immediate than either of the preceding : — viz., to the more composite chemistry of their structure, and the more rapid and energetic change of their substance. The structure of every animal is so far self-regulative, as to determine the perma- nence of its own composition, by a process of which the blood is one main agent, and the tis- sues generally another. But there is no rea- son why we should exclude a third — why we may not suppose that the chemical assimila- tion or likening of the foreign substances taken as food is commenced in the course of the digestive act — why, in short, the absorp- tion of more numerous, abundant, and com- plex alimentary principles may not necessitate the co-operation of a more highly developed digestive organ. HUMAN ANATOMY. — The alimentary canal of Man is a long membranous tube, which, commencing at the mouth, successively occupies the regions of the neck, chest, belly, and pelvis, to terminate at the lower orifice of the latter cavity in the aperture of the anus. In this course, the canal first forms at the back of the mouth a dilatation, called the PHARYNX. It next contracts into a straight cylindrical tube, the (ESOPHAGUS, which is continued through the neck and chest. Immediately after perforating the diaphragm, or septum which divides the thorax from the abdomen, it expands into the STOMACH (c,fig. 241.). An external constriction and an internal valve (P, Jig. 241.) mark the boundary between this organ and the INTES- TINE, which forms the remainder of the tube. And, finally, at about five-sixths of its length, the intestine is subdivided into two portions, by an alteration in size and character, which commences at a point corresponding to the presence of a caecum or blind pouch exter- nally, and of a valve internally. Of these two segments, the upper, longer, and narrower, is called the SMALL INTESTINE (j, i,fig. 239.) ; and the lower or wider, the LARGE INTESTINE (cc, AC, TC, DC, sc, R,^. 239.). Fig. 239. Stomach and intestinal canal of the adult human subject. c P, stomach ; c, cardiac ; p, pyloric orifice ; j i, small intestine; j, jejunum; i, ileum; c c to A, large intestine, viz. : — -C c, caecum ; A c, ascending colon ; T c, transverse colon ; D c, descending colon ; s F, sigmoid flexure or sigmoid colon ; n, rectum ; A, anus. It is the three latter portions of the ali- mentary canal, — viz., the stomach, small in- testine and large intestine, — which form the especial subject of the following article. They all possess the same general structure ; being composed of three coats or tunics — an exter- nal and serous, a middle and muscular, and an internal and mucous coat. The first of these constitutes their means of attachment to x 2 308 STOMACH AND INTESTINE. the trunk in which they are enclosed ; and it limits, permits, and facilitates those move- ments, which it is chiefly the office of the second to execute. The third is the most important, since it forms the complex secreting and ab- sorbing surface, upon which the functions of the canal mainly depend. Between these three tunics are interposed two layers of areolar tissue ; containing vessels, nerves, and lympha- tics for their supply. The various modifica- tions undergone by these constituents of the tube, in the three segments just distinguished as the stomach, small intestine, and large in- testine, will form the chief features of the fol- lowing description. The STOMACH is the widest and most di- latable part of the alimentary canal. Its form varies greatly in different indivi- duals. Removed from the body, and mode- rately distended, it generally takes the shape represented in Jig. 240.*; — a shape which is often compared to that of a bagpipe, arid may be best described as a bent cone, the concave aspect of which is joined by a tube at one- fourth of the distance from its base. In it we distinguish an anterior and a posterior surface; a superior and an inferior border; a right and a left extremity; together with the cardiac and pyloric apertures, by which it communicates with the oesophagus and duodenum respec- tively, and thus becomes continuous with the remaining portions of the digestive canal. The description of these different parts will vary, according to the full or empty state Fig. 240. Stomach and duodenum. The tube has been everted and inflated, and its mucous membrane dissected off, so as to show the subjacent muscular coat. a g, cardiac orifice; b h, pyloric valve; a e b, lesser curvature, or upper border; g dfc h, greater curvature, or lower border. (The dotted lines joining a e, e b, and c h are intended to illustrate the mode in which extreme distention of the organ affects these curves) ; g d, cardiac pouch ; b h c e, pyloric pouch. (The surface to the right of the line which would unite eg represents the oblique, that to the left of this line the circular, layer of the muscular coat of the stomach.) of the organ. Thus in the latter con- dition, the stomach is flattened vertically ; so that its anterior and posterior mucous surfaces come into contact, while its upper and lower margins form thin edges, each of which really deserves the title of a " border." But when distended, any transverse section of the organ would be nearly a circle ; and hence its borders and its surfaces disappear by merging into each other. Its uppermost part, however, is still distinguished as the lesser curvature (a, e, b, Jig. 242.), and the lower as the greater curvature (g, d,f, c, h). It will be seen that the general concavity of the former curve is especially marked in its first half or two-thirds ; at the end of which part (e) it usually becomes slightly convex. A very shallow notch (c) opposite to this point often divides the greater curvature into two portions ; and the two constrictions together define the commencement of the pyloric pouch (6, h, c, e). The cardiac pouch, or great or splenic extremity (d), lies to the left of the cardia or the cesophageal opening («), beyond which it projects for about three inches. At this aperture the oesophagus dilates gradually, so as to resemble an inverted funnel. To the right of the oesophagus, the stomach expands slightly, and hence reaches its maximum dia- meter at about the middle of the organ (/). Beyond this point it gradually tapers away to the pylorus (b, h), where a sudden external constriction marks the site of the valve. The dimensions of the organ are even more variable than its form. The author's mea- surements are not sufficiently numerous to jus- tify him in offering them as valid averages; but he has generally found that, in a state of mo- derate distention, its length is about 13 to 15 inches, its diameter at the widest part 5, at the pylorus 2, or through the whole organ 4, inches. Hence its total surface would equal about li square feet ; and its capacity about 175 cubic inches, or 5 pints. Its weight may be estimated at about 7 ounces. These estimates are a little larger than those of most other anatomists. The attachment of the stomach is chiefly effected by the continuity of its extremities * This woodcut is so far inaccurate, that the pyloric constriction is shown more distinctly than it" could be actually seen in such a view, in which it would be partially concealed by the backward curve of this part of the stomach. STOMACH AND INTESTINE. 309 with the more fixed duodenum and oeso- phagus. The former tube is connected with the posterior wall of the belly, the latter perforates the crura of the diaphragm a little to the left of the median line, so as to enter the abdomen about one inch in front of the left border of the aorta, by an aperture which is everywhere muscular *, although close to the posterior border of the tendon. The fixation of the stomach is also aided by certain processes of peritoneum. To the left of the oesophagus, the short phreno- gastric omentum passes from the diaphragm to the cardiac pouch, which it reaches some- what posteriorly. Still lower down, the stomach is united to the spleen by the gas fro - splcnic omentum. The lower border of the organ gives off the great omentum : this de- scends for some distance towards the bottom of the belly, and is then reflected upwards to the anterior border of the transverse colon, which it splits to enclose. The upper border of the stomach is attached by means of the gastro-hepatic or small omentum, which de- scends from the transverse fissure of the liver. All of these folds are double; though the four layers of the reflected omentum majus are often inseparably united to each other. They are more particularly described in the article PERITONEUM. Situation. — The stomach is placed almost transversely in the upper part of the abdo- minal cavity, in which it passes from the left to the right side, as well as downwards, and slightly forwards. This direction results from its situation relatively to the oesophagus and duodenum : since it is joined by the former at its highest part, and near its left extremity ; while the latter is immediately prolonged from its right or pyloric end. In this course from left to right, the stomach successively oc- cupies the left hypochondriac and the epi- gastric regions ; and, just at its termination, it reaches the right hypochondrium. Its an- terior surface is therefore in contact with the diaphragm, where this muscle lines the car- tilages of the left false ribs ; and with the ante- rior wall of the abdomen. Its posterior surface lies upon the pancreas, the aorta, and the crura of the diaphragm, where these parts cover the spine. Its left extremity is in contact, above, with the diaphragm, below, with the spleen ; and, posteriorly, it touches the left supra- renal capsule and kidney. Its upper border is in apposition to the liver: — viz. to its left lobe, to the lobulus Spigelii, and to part of the lobulus quadratus. Its lower border is parallel, and close to, the transverse colon. * The muscularity of this aperture led Haller and some other anatomists to regard it as a kind of sphincter to the cardiac orifice of the stomach. But we may point out that, though the contraction of its fibres reduces the elliptical opening to a circular one, yet as this apparent constriction coin- cides with the descent of the diaphragm, the oblique plane of this muscle is at the same instant becoming transverse. Hence this ellipse and circle merely represent an oblique and a transverse section of the same cylinder. The diameter of the oesophagus may therefore remain unchanged. Unusual size or distention chiefly affects the situation of the organ by causing it to ex- tend downwards ; so as to overlap or cover the transverse colon, and thus reach the umbilical, the left' lumbar, or even the iliac region. Under similar circumstances, its left extremity also passes deeply into the corre- sponding hypochondrium ; so as to be co- vered, not only by the cartilages of the ribs, but by these bones themselves. Its extension upwards diminishes the size of the thorax, but is rarely sufficient to be felt as a serious hindrance to the descent of the diaphragm in the ordinary tranquil inspiration of health. Its right extremity may reach the gall-bladder. It may be useful to trace the effect of its usual progressive distention upon the form, site, and fixation of the stomach. When void of food, and not distended (as it often is) by gases, the flattened stomach hangs almost vertically in the epigastrium. In this state of the organ, the pulpy food that enters it from the oesophagus drops at once into the cardiac pouch, which forms its most depend- ing part. The reception of further quantities effaces its upper and lower borders, and gra- dually changes them,from almost straight lines, into the curves above mentioned ; at the same time that it separates the previously apposed surfaces, and converts the whole organ into a bent cone, which is convex below and in front. The latter of these two flexures chiefly occupies the pyloric extremity, and is often very suddeu. Both result from the increased length of the organ, and the proximity of its comparatively fixed orifices. But both are greatly assisted by the muscular coat : since the distention of the separated stomach tolerably imitates, though it scarcely equals, the curves taken by the organ when moderately expanded in situ. The delicate and yielding omenta above men- tioned allow the stomach to expand be- tween their elastic and extensible laminae, without undergoing any disturbance of its ner- vous and vascular connections, or any loss of its serous covering. Finally, although the stomach itself enlarges pretty equally in all di- rections, still, after filling the hypochondrium, the mobility of its bent middle directs it towards that part of the enclosing cavity where it meets with the least resistance : — namely, towards the yielding anterior wall of the belly. Hence, should the distended intestines not allow it any great descent downwards, it comes forwards ; so that what was its vertical anterior surface now looks obliquely upwards ; while its inferior border touches the lower part of the wall of the epigastrium, where its artery has even been felt pulsating in very thin sub- jects. The serous coat of the stomach is conti- nuous with the double laminae of peritoneum above mentioned, which split to enclose it where they reach its various borders. Here they are very loosely connected to each other, and to the subjacent coat, by an abundance of highly elastic areolar tissue. But towards the middle of the gastric surfaces, the peritoneum, though still elastic, is closely united to the x 3 310 STOMACH AND INTESTINE. subjacent muscular tunic. The advantage of such a yielding attachment has already been alluded to. For a description of the structure of this tunic, the reader is referred to the articles PERITONEUM and SEROUS MEM- BRANES. The muscular coat of the stomach consists of the unstriped or organic muscular fibre ; which the researches of Koelliker have shown to consist of fibre-cells, such as are represented in fig. 241. The form and dimensions of these long and spindle-shaped elements vary little in the different parts of the intestine and stomach. Their length is from ^i^ to T^th of Fig. 241. Fibre-cell from the unstriped muscle of the intestine. Magnified about 350 diameters. (After Koel- liker.) a, nucleus. an inch : their breadth from ^ Ao to ToWth at the middle, where they are flattened, and from whence they taper off to conical and pointed extremities. They contain a nucleus ; which is from -^^- to y^th of an inch in length, and about a sixth of this in breadth. Their tex- ture is a pale substance,which generally appears to be homogeneous, but is sometimes seen to consist of a membrane* enclosing granulated * From a comparison of very numerous observa- tions, the author entertains no doubt that this or faintly striated contents. In some instances, they are marked by swellings ; which, as they are rarely seen in the associated fibres, are probably due to casual local contractions of the sarcous substance itself. The arrangement of these fibre-cells is very simple; they are packed together in parallel rows (fig. 242.), their flattened surfaces adhering strongly Fig. 242. Portion of a bundle of fibre-cells from the muscular coat of the intestine. Magnified 250 diameters. a, nuclei of the fibre-cells. to each other. They thus form small and broadish bundles, between which are interposed the vessels for their supply, en- closed in a sparing quantity of areolar tissue. The union and interlacement of such fasci- cles of cells, builds up the large flattened strata of the muscular coat of the intestines. The fibre-cells are developed by the longitu- dinal extension of an oval cell ; in which is deposited a special sarcous content, that soon obscures the original cell-membrane. We shall hereafter see that these fibres sur- round the intestine in two layers: an external, membrane is always present, being only obscured by such circumstances as delicacy, adhesion, or re- fractility. In the fibre-cells of the adult human pylorus, he has often verified a distinct cell-wall or sarcolemma. And the reappearance of this membrane in the unstriped muscular fibre of the human uterus, as its cells recede or degenerate after parturition, is only one of many significant instances, that we cannot deduce the real absence of such a delicate membrane, from the mere fact of its ceasing to be visible under the microscope. STOMACH AND INTESTINE. 311 which is longitudinal : and an internal, which is circular or transverse — a general arrange- ment to which even the stomach forms no real exception. Before the discovery of the fibre cell by Koelliker, it was a matter of fruitless speculation, how these unstriped fibres termi- nated;— in other words, what was their indivi- dual length. But although this question is of course set at rest, it still remains doubtful, whether the transverse fibres of the alimentary canal return into themselves on completing one circle of the tube, or whether they take a spiral course. The latter view appears to the author much more probable. For some of their bundles often appear to join each other at a very acute angle. And whatever be the precise mechanism of their really co-ordinate contractions, it is clear that, in the longitu- dinal fibres, the direction and progress of con- traction correspond to the axis of the cell : — that is, to the line uniting the greatest number of its sarcous particles. While it is equally obvious that, if the course of these transverse fibres were absolutely circular, the peristalsis of the whole stratum they compose would move at right angles to their axes. Such a difference in their contraction would be so unlikely, as to justify our preferring the sup- position of their spiral arrangement. For this would allow of an identity in the contractions of the two strata in this respect. The course of contraction would be axial in both sets of fibres ; but, c&teris paribus, slower (and hence apparently more local) in the far longer bundles of the transverse coils. The spiral currents hereafter alluded to as seen in the contents of the stomach perhaps strengthen this supposition. The longitudinal layer of the stomach is de- rived from the similar tunic of the oesophagus. This, on reaching the cardia, radiates on all sides, its bundles becoming thinner as they diverge, and being gradually lost from their decussation and mixture with the various fibres they meet with. But, on the lesser curvature of the organ, they continue much more distinctly, and are often traceable as two or three broadish bundles, to within a short distance of the pylorus. The longitu- dinal layer which covers the pyloric extremity appears not to have any very direct con- tinuity with the preceding. Its constituent fibres arise by scattered bundles at about the middle of the organ, and — often first uniting into two broad bands which occupy the cen- tres of its anterior and posterior surfaces — they soon form a tubular layer, which pro- ceeds over the pylorus, to join the com- mencement of the duodenum. The transverse or circular fibres lie immedi- ately beneath those of the longitudinal stratum; and form what is, on the whole, a thicker, if not a more uniform, layer. To the left of the cardia its rings are very few and indistinct: their places being taken by those of the third or oblique layer. But from the right of this orifice it continues towards the pylorus with a constantly increasing thickness; until finally, reaching the margin of this valve (fig. 243.), it is inflected towards the axis of th e stomach by a rather steep and sudden curve, which presents an almost vertical surface Fig. 243. Longitudinal section of tfie alimentary canal at the junction of the stomach and duodenum, to show the thickness of the pyloric valve. *, pyloric sac of the stomach ; d, commencement of the first portion of the duodenum ; j9, pylorus, formed by a thickening of the transverse layer of the muscular coat of the stomach. towards the duodenum. Those of the trans" verse fibres which lie nearest to the left ex' tremity are somewhat less regularly transverse. Hence some of them decussate slightly with each other, while others, which pass down- wards from the right margin of the cardia, are directed somewhat obliquely towards the left extremity of the organ. The third or oblique layer lies more deeply than the two preceding, and is therefore best seen by everting and inflating the stomach, and carefully removing its mucous membrane. Where the oesophagus enters the stomach, the transverse fibres of its left margin are so close to a flattened bundle of fibres, which occupies the notch (g,fig. 240.), limiting the cardiac pouch, that the two are visibly continuous. The right or thickest part of this flattened band passes obliquely downwards towards the right side, soon breaking off from the termination of the oesophagus ; and from hence it continues across the transverse layer just described, to reach the greater curvature, where the similar layers from both surfaces of the organ are reflected into each other. Its usually well-defined margin occupies — and indeed forms — the notch (c,fig. 240.). The posterior or thinner part proceeds, not only from the depression (g,./%. 240.) on the left of the cardia, but also from the neighbouring upper border of the great extremity; and its more vertical fibres are also continued downwards to the lower border of the stomach, where they meet, so as to complete the circuit of the cardiac pouch. Movements of the stomach. — That there is an intimate connection between the oesophageal and gastric movements, is only what might be expected from that visible continuity of their muscular coats which has just been alluded to. Thus, at the close of each act of deglutition*, the lower fibres of the oesophagus contract with such force, as not only to obliterate the cardiac aper- ture, but even to cause the mucous membrane of this part to project into the cavity of the * For a description of the act of deglutition see the articles " (ESOPHAGUS" and " PHARYNX." x 4 312 STOMACH AND INTESTINE. stomach.* This condition remains for some instants. And when the alimentary bolus has in this manner been impelled into the organ, it excites muscular movements. The exact condition of the cardia during stomach digestion is scarcely known. It is obvious that the force with which it is shut must be effectively superior to the pressure exerted on the contents of the organ by the gastric contractions. Still we are igno- rant how much of this force is due to the contraction of the lower eesophageal fibres, and how much to the shape, position, or structure of the stomach itself. Indeed, one cannot help conjecturing, that the de- cussation of the transverse and oblique fibres of the organ around the insertion of the oesophagus, might render their contractions a material assistance to the obliteration of the lower part of this tube. From the ob- servations of Magendief , it would seem that, during digestion, the cardia contracts tightly around a finger introduced from the stomach ; and that the distention of the gastric cavity appears to regulate the intensity and duration of this closure, — so much so, that pressure by the hands, or by the diaphragm during inspiration, produces an increase of contrac- tion. $ And the disappearance of this efficient closure in the dead, or even in the exhausted § animal, suffices to show, — what indeed we might gather from its great energy, — that it is not due to mere passive contractility. Hence, on the whole, it appears preferable to regard the cardiac orifice as closed by an active muscular contraction, which is itself excited by the direct stimulus of the food that distends the stomach. Perhaps there are few more difficult parts of our inquiry than that which relates to the precise nature of those movements which are executed by the stomach, and impressed upon the food, during its sojourn in this cavity. For the vivisection of animals has given few results ; and even had they been more marked, they would scarcely have been trustworthy. The human corpse is generally diseased, or, if not, the interval after death which precedes an ex- amination of its abdominal viscera is suffi- cient to remove all appearances of activity. * Beaumont (Experiments and Observations on the Gastric Juice. Combe's Edition. 1808), pp. 62, 63., and elsewhere. Valentin, Lehrbuch der Phy- siologie, Band i. p. 269. Magendie, Precis ele- mentaire de Physiologic : Quatrieme Edition, vol. ii. p. 70. f Op. cit. pp. 81, 82. I Magendie (foe. czV.) and Mueller (Handbuch der Physiologic, Bd. i. p. 412) state that an alter- nating and rhythmical movement of the ossophagus accompanies digestion. It is independent of deglu- tition. The contraction of the tube coincides with the period of inspiration ; and, vice versa, its relaxa- tion with expiration. But such results of vivisection cannot be safely regarded as the ordinary pheno- mena of the healthy body. As to how far the cardia is necessarily closed by the diaphragm in the act of inspiration, I may refer to the note to p. 309. : — to which I will only add, that any one may satis- factorily disprove its real occlusion by swallowing a bolus of food at this period. § Magendie, loc. cit. And, finally, the results obtained from newly- killed animals on the one hand, and from Dr. Beaumont's valuable case on the other, are apparently so indefinite, or even so conflicting, that most physiologists seem content to leave the question in abeyance, until more numerous or more comparable facts afford better grounds for a decision. A careful comparison of such results has, however, led the author to adopt the follow- ing views*, which appear to unite in one theory most of the facts hitherto ascertained respecting the muscular action of the healthy digesting stomach. 1. In the fasting state the empty stomach offers no movement whatever. This fact, which is asserted by Dr. Beaumontf , from his obser- vations on the living human subject, may be readily verified by laying open the bellies of the domestic mammalia immediately after death. Some very slight and gradual changes in the shape of the organ, which I have once or twice noticed, form no valid exception to such a rule. This agreement in the above two classes of results is not only interesting in itself, but entitles us to lay somewhat more stress on that which follows. And it is especially useful, in that it frees us from the apprehension that any contractions which we may observe can be caused, or even greatly modified, by the air J to which the dead animal's stomach is ex- posed. 2. At the commencement of digestion, or immediately after the deglutition of food, the movement of the stomach offers three varieties. a. In some animals, a large quantity of food is often hastily swallowed, after scarcely any sub- division, far less mastication. Under these circumstances, the stomach is found closely contracted around its hard contents, some- times even adapting its shape to that of these unyielding masses. And, as might be ex- pected, no motion is discernible.^ b. Dr. Beaumont narrates the opposite ef- fect of a very small quantity of liquid food in the human subject. It excites a vermicular action, a gentle contraction or grasping motion of the stomach, so that the wrinkles of the * These will be found in an Essay which, writ- ten in 1847, was published in the " Medical Gazette " for 1849. f Beaumont, at p. 105. expressly ; at pp. 23. 57., by implication. J Though, by the bye, as this would chiefly cause irregular motions, it would rather oppose, than pro- duce, any uniform and constant movement. The effect of air on the intestine is alluded to hereafter. § This condition, which is frequent in the domestic Carnivora, appears to be usual in the Rabbit, in whom it is often kept up by the comparatively unyielding nature of the food. In such a case the contents of the stomach are dissolved, as it were, from without inwards, in successive strata ; which are slowly and constantly stripped off by the muscular action, and squeezed through the pylorus. In all these instances I have found the movements of the organ much less marked than where the food was present in a smaller quantity and a state of greater subdivision. And in the Rabbit, both the stomach and intestine appear to be unusually sluggish ; as shown by the feeble movements of the former during digestion, and of the latter under the magneto-electric stimulus. STOMACH AND INTESTINE. 313 mucous membrane gently close upon it, and gradually diffuse it over the whole surface.* c. The ordinary state of the human stomach during the diges'tive act lies between these two extremes; and may be defined as one of moderate distention, with food which has been subdivided by mastication, and diluted with saliva and gastric juice, so as to possess a pulpy or semi-fluid consistence. In attempting to imitate this condition in the Dog, I have found it best to choose an aliment which already possesses a pultaceous or semi-liquid consistence, — such as a thick soup, — and to administer it in large, but not excessive quantity. On pithing the animal a quarter of an hour afterwards, the following movements are seen. The most noticeable is a peristalsis or transverse constriction, which sets out from the cardiac extremity, and tra- vels slowly towards the pylorus. It is com- paratively feeble until it reaches the junction of the pyloric two-fifths, and the cardiac three- fifths of the organ. Here it suddenly becomes much more distinct ; and from hence continues rapidly forwards, as a well-marked circular depression, until it reaches the pylorus. Hav- ing arrived there, an interval of relaxation suc- ceeds, and is followed by the recurrence of a similar contraction. As nearly as can be judged, the average period of relaxation is about one minute, and the contraction itself occupies nearly the same time. Cotempora- neous with this contraction there is a cer- tain amount of longitudinal shortening of the organ. The pyloric orifice is always firmly shut. In the interior of the human stomach, Dr. Beaumont could only verify an alternate con- traction and relaxation ; a vermicular action of the transverse fibres, and a shortening pro- duced by the longitudinal coat. The exact details of this occurrence he could not follow. He also noticed a constant agitation of the organ produced by the respiratory muscles.f But Dr. Todd and Mr. Bowman J have men- tioned a case, in which the vermicular actions of a distended stomach were distinctly seen through the wall of the belly during life. So far as this imperfect evidence goes, it is evidently favourable to the view, that the muscular contraction of the human stomach during this stage of digestion is similar to that seen in the newly-killed animal. It is therefore our next object to inquire — (1) What are the movements which such a peristalsis would necessarily impress upon the food ? And (2) how far do they correspond with those which have been actually ob- served ? (1.) The effect of peristalsis in a closed and * Condensed, in Dr. Beaumont's own words, from pp. 62, 63. 96, 97, of his work. This activity of the rugae themselves may remind us of their inherent muscularity (see p. 325. of this article). f Probably much exaggerated, if not chiefly pro- duced, by the adhesion of St. Martin's stomach to the wall of his chest. J Todd and Bowman's Physiological Anatomy, vol. ii. p. 196. distended tube may be represented by an in- flexible hollow cylinder, filled with liquid, and accurately fitted with a perforated septum (6, fig. 244.), which is capable of free movement along its interior. Let such a septum be moved in either direction, and it at once exerts a pres- sure on the body of liquid (c) contained in that end (a) towards which its motion sets. The pressure being equal in all directions, a portion of the fluid escapes backwards through its aperture (> ^SlSiflg^ Tubes from the cardiac and pyloric regions of the Dog's stomach, to show the contrast of their struc- tures. Magnified 60 diameters. Altered from Koelliker. A. pyloric tube ; a, primary tube ; b, three second- ary tubes. B. cardiac tube ; a, primary tube lined by columnar epithelium ; b, two secondary tubes ; c, four terminal branches containing large oval cells. STOMACH AND INTESTINE. 323 They everywhere bound a tube with a dis- tinct calibre. In the cardiac region, it is only the ridges, and the upper part of the tubes, which are covered by columnar epithelium. At the first (B b, fig. 24-8.) or second bifurcation of the primary tube, the character of its lin- ing altogether changes : and from hence onwards to their rounded blind extremities, the secondary tubules are immediately lined by peculiar oVal cells (B c, fig. 243.). These cells are analogous to those seen in the human stomach. They differ however from them, not only in their great size, and more distinct walls," but also in the fact, that they generally bulge the basement membrane of the tube, so as to give it a somewhat moni- liform outline. A closer examination shows this appearance to be caused by the prominent cells occupung irregular heights around the wall of the tube. On getting the middle of such an isolated tube into the focus of the microscope, we find tiiat in the higher part of the tuDule, near where it opens into the primary tube, the oval cells, which are always in immediate contact with the basement membrane, form a double row with a somewhat sinuous interval. This interval is a distinct though narrow calibre. Below this visible calibre, I had long been aware that the similar interval between the larger cells was occupied by an immense number of small nucleated cells or cytoblasts, — many of which are firm, with dis- tinct and somewhat angular outlines; while others are excessively delicate, pile, flattened, oval, transparent, and of equal or much smaller size. And the more skilful manipulation of Koelliker has recently enabled him to state, that the centre of the tube presents a con- tinuous narrow calibre or cavity (-*,/#. 249.), which is immediately bounded by these small, roundish, or angular cells (c, A and B). Be- tween these small cells and the limitary mem- brane, the large oval cells are interposed (b, A and B). Bt?low, the latter often seem to form the sole contents of the tube. The truth of Koelliker's description I can fully substantiate ; so far as regards the upper part of these secondary tubes, in the cardiac five-sixths of the organ. Even the blind ex- tremities of the tubes seem to have their axes occupied by the delicate cytoblasts pre- viously alluded to ; but they are here, so far as I can see, disposed irregularly. Higher up, the cells are more angular, and possess more distinct outlines; and are often arranged in two rows, which are in contact at the centre of the tube. It is only towards the apertures of the secondary tubes," where the oval cells are beginning to be more thinly scattered prior to their disappearance, that these small cyto- blasts appear to form a distinct calibre or tubular cavity of appreciable width. Here they merge into the columnar form; — a change which begins by their becoming elongated to- wards the axis of the tube, and allowing water to develope a distinct cell-membrane at this part (c,Jig. 249.). But there are many appear- ances which render it by no means impossible that the whole length of the tube possesses a narrow calibre, formed by a regular arrange- Fig. 249. Portions of tubes from the cardiac extremity of the dog's stomach. Magnified 350 diameters. (Partly after KoeUiker.) A. portion from the middle of such a cardiac tube ; a, limitary membrane of tube ; b, large oval gastric cell ; c, smaller axial cells. B. Same seen in transverse section ; a, b, c, as above. External to c are seen indistinctly some delicate cytoblasts ; c, junction of the primary and secondary tubes, show- ing the mode in which the small axial cells of the latter are continuous with the columnar cells which form the epithelium of the former. ment of these small cells. While I have no doubt that the interstices left between the large cells and this central tube of epithelium are also filled up by numbers of cytoblasts, of excessive delicacy, and various degrees of mi- nuteness ((/, B and c). Besides these free cytoblasts within the tube, we may find others of endogenous origin. Very careful observation of the large oval cells will show that they enclose cytoblasts in addition to their minutely granular contents (compare 6, Jig. 246.). The number of these cytoblasts ap- pears to vary from two to twenty in different cells. They are excessively delicate, of about 1nnrvth inch diameter: their shape is a flat- tened oval ; and they contain a bright spot or nucleus. They seem to be chiefly in contact with the inner surface of the mother-cell ; so that in many animals, specimens of their out- line can often be distinctly seen through the nearly transparent wall of this cell under the higher powers of the microscope. They may, however, be easily overlooked. And their distinctness never equals that of the proper nucleus of the cell ; closely as they resemble this structure in size and shape. They may sometimes be seen projecting from the broken half of a mother-cell ; or set free from it, owing to its having been ruptured by the Y 2 324 STOMACH AND INTESTINE. rapid endosmose of water. But they are very quickly dissolved or burst, by contact with most of the fluids which are generally used in preparing such specimens for microscopic examination. During the five years that I have made the stomach an object of frequent (though inter- rupted) research, I have examined numerous specimens from the perfectly fresh stomachs of about thirty species of Vertebrata. The following is an outline of the few results I have obtained. As regards the pyloric tubes, those of the Cat, Rabbit, Hog, Ox, and Guinea-pig, resemble those of the Dog, in containing a columnar epithelium, and having a distinct calibre to their termination. Those of the Horse resemble the tubes of the human stomach in possessing the oval or gastric cells. In most, if not all of these animals, the tubes ramify. As respects the cardiac tubes, the minute central calibre observed by Koelliker in those of the Dog appears to be also present in the Cat and Guinea-pig ; and, from analogy, is not unlikely to exist in most Vertebrata. The large oval cells are the rule throughout the Vertebrate kingdom. And in many Rep- tiles, as well as in the very young animals of most orders, the numerous cytoblasts enclosed by these cells are much more distinct. In only two instances have I found no large cells present in the cardiac tubes, and in both of these, the stomach was evidently disorgan- ized by commencing putrefaction. In some Fishes, however — such as the Mackerel — it is only the middle or apex of the F-shaped stomach which is occupied by tubes. And in the Minnow, Carp, and Tench of the Cyprinoid genus, as well as in the river Lam- prey (Pelromyzon fluviatile) no tubes are present. Finally, while there are many species in which the gastric structures appear to be softer and more delicate during the time of digestion than in the fasting state, in none have I been able to verify the least difference in the morphology of the organ at these two periods. Those who are familiar with the diffi- culties that oppose the successful examina- tion of the softer tissues of the animal body •will probably bear with me if I end this de- scription by what may seem a superfluous caution to the observer. There are many appearances seen in these delicate tubes, which are produced by the mechanical violence necessary to their isolation, aided by the softening of incipient putrefaction or self- digestion, or by the endosmose of the di- lute fluids which are sometimes added to such specimens in preparing them for the microscope. Thus the tubes often deviate from the above account in the absence of gastric cells, in the presence of short branches that are given off near their blind extre- mities, and in the spiral or bulbous shape which these ends sometimes assume. Indeed, when we reflect upon the extreme tenuity of their basement membrane, the nature of their contents, and the firmness with which they are imbedded in a dense areolar and muscular tissue, we shall scarcely be surprised to find, that the violent disruption of these attach- ments can distort the tubes, or break up their soft contents. But the careful manipulation of perfectly fresh specimens, in a proper fluid me- dium (such as the serum of the blood, or a strong solution of common salt) renders these appearances so rare, as to render it highly probable that they are accidental. While conversely, the application of a slight pres- sure, the use of water and dilute acids, and the commencement of digestive or putrefactive softening, will often produce them in a spe- cimen from which they were formerly absent. In addition to the cylindrical tubes, some * anatomists have found in the stomach ramified glands, which end in acini or dilated extre- mities. These are stated to occupy the neighbourhood of the pylorus, wherethey form a kind of transitional structure between the gastric and the duodenal glands. I have once or twice seen appearances in the tubes of this part which corresponded pretty closely with the above description. In two other instances, a single flask-shaped dilatation was appended to some of the ordinary tubes, which it thus doubled in diameter. But the arrangement of these latter dilatations, as well as the condition of the remainder of the specimens, left me little doubt that they were due to accidental violence, which had distended the terminal branches of a tube with a large portion of its displaced contents. While their shape and situation (in the mucous membrane itself, instead of its submucous tissue) sufficed to show that they were not lenticular glands ; — an argument which will equally militate against the notion of their being a transition to the duodenal glands, since these occupy a similar position. Lenticular glands are also found in the stomach. As regards their shape, size, situation, and contents, they correspond so completely with the solitary glands of the intestine, that we may refer the reader to these for their special description. Their number varies extremely. Sometimes it is im- possible to find any. In other specimens, they are scattered more or less thickly through- out the whole organ. They are said chiefly to affect the lesser curvature ; but I have seen them sown very plentifully over the pyloric region only. In children* they are rarely absent. And among the brute Mammalia, they are found occasionally in the Dog f, and constantly in the Pig. % Structures more or less analogous to these glands probably also exist in the Beaver, Kangaroo, Dugong, and many other animals. Matrix. The cylindrical tubes of the sto- mach are united to" each other, in their whole length, by a sparing quantity of a fibrous * Bruch (in Henle and Pfeufer's Zeitschrift. f. Rat. Path. Bd. viii. p. 272. et seq.) ; Ecker (id. op. 1852. p. 244.). Compare Bischoff (in Mueller's Ar- chiv. 1838. p. 503.) f Bischoff, Op. cit. p. 510. j Id. op. ; also Wasmann (DeDigestione Nonmilla. Berlin. 1839. p. 8.), and Koelliker, Op. cit. p. 150. STOMACH AND INTESTINE. 325 network or matrix; — their blind extremities being also imbedded in a considerable stratum of this texture, which is continuous with that surrounding their sides. The arrangement of the latter part of it is best seen by making hori- zontal sections of the mucous membrane, so as to cut transversely across the gastric tubes at different heights. Its quantity is small in proportion to the diameter of the tubes. And in it we may recognize, besides cut extremities of vessels, indistinct concentric fibres, which appear to surround the tubes, and decussate with each other. In the ramified tubes of many animals, each original tube, and its set of secondary branches, is enclosed in a tole- rably thick sheath of this kind, which gives off slenderer partitions of the same nature between the smallest individual tubes. On the surface of the stomach, this matrix is nearly homogeneous ; but its fibrous cha- racter is more distinct at the deeper parts of the membrane, and in those tubes which occupy the neighbourhood of the pylorus. Here its quantity is also increased. Many years ago, the author was struck with the re- markable difference between that layer of this fibrous tissue which lies beneath the tubes, and the submucous areolar tissue upon which it is placed ; — the former being characterized, not only by its darker colour, and its dense and closely interwoven texture, but also by its being much less acted on by acetic acid. But Middeldorpf* has since made the im- portant discovery, that this peculiar layer, which extends from the cardia to the anus, is in reality composed of a mixture of areolar tissue, and organic or unstriped muscle: — the fibres of the latter structure being arranged in two series of bundles that decussate with each other at an acute angle. Externally, these fibres are conjectured by Kcelliker* to be more or less continuous with the ends of the oblique fibres of the muscular coat. Internally, Bruecke states them to pass upwards, in small bundles, between the several tubes. This statement is to some extent confirmed by Koelliker, who has seen numerous cells very like the fibre-cells of organic muscle occupying this situation in Man, some Ruminants, and the Pig. In the latter animal, bundles of these fibres penetrate the rudimentary villi of the pylorus, and occupy their axes. Of the function of these muscular-fibre cells we know nothing. But, from their arrangement, it would seem not impossible that they are destined to maintain the tubes in their normal situation, against the disturbances which the contractions of the proper muscular coat might otherwise produce. Areolar tissue. A layer of loose submucous areolar tissue (the tunica nervea of some authors) connects the mucous membrane of the stomach with the proper muscular coat pre- viously described. Seen in vertical section, its thickness is a little greater than that of the denser muscular stratum which receives the ex- * De glandnlis Brunnianis. Vratisl : 1846. tremities of the tubes. Its constituents are the ordinary white and yellow fibrous ele- ments ; the elastic filaments of the latter being chiefly of small size. Externally, it is pretty firmly connected with the muscular coat, and appears to receive many of its fibres. But internally, where it approaches the fibrous matrix, its meshes are very large and loose, so as to allow of the mucous membrane being thrown into folds by the contraction of the muscular tunic. ft contains the vessels, nerves, and lymphatics destined for the supply of the mucous mem- brane. The vessels of the stomach are very large and numerous. The arteries are derived from the abdominal aorta. The veins empty themselves into the vena portcet which rami- fies in the liver. The arteries of the stomach all come off from the coeliac axis. This vessel, which leaves the aorta opposite the first lumbar vertebra, continues obliquely forwards as i\ short thick trunk for a distance of about half an inch ; when the " axis " ceases, by giving off, at right angles to itself, three large branches : — namely, the gastric, hepatic, and splenic. Fig. 250. Arteries of the stomach. The coeliac axis, as seen by raising the liver, and depressing the stomach. a, arteria coronaria ventriculi ; b, gastric branches of the same; c, arteria hepatica ; d, arteria gastro- duodenalis; e, arteria gastro-epiploica dextra; g, arteria py lories ; h, arteria splenica ; i, arteria gastro- epiploica sinistra. The arteria coronaria ventriculi (a, Jigs. 250, 25 1 .), or proper gastric artery, is the smallest of these three. It passes upwards and towards the left side, beneath the peritoneum which forms the dorsal and outer surface of the sac of the Y 3 326 STOMACH AND INTESTINE. omcntum ; until, arriving nearly at the upper extremity of this cavity, it turns forwards in a slight projection or fold of the serous mem- brane. In this fold, it has a very brief and somewhat arched course, which brings it to the left end of the smaller curvature of the stomach. Here it passes between the two layers of the gastro-heptitic omentum. From hence it continues, in a very tortuous course, along this curvature ; lying close to the stomach, and diminishing in size by giving off frequent branches; until, towards the right or pyloric extremity of the organ, it is lost by anastomosing with the branches of the hepatic artery. Its larger or named branches are the ceso- phagcaland the gastric. The first are given off from the highest point of the vessel, or where it enters the gastro-splenic omentum. They run upwards to the oesophagus, and take a longitudinal course ; so as to pass, with this tube, through the opening in the diaphragm. And they anastomose with the thoracic vessels distributed to this tube from the aorta. The gastric ramifications (b,jfig. 250.) run down- wards from the coronary artery on both surfaces of the stomach. They inosculate, on the left, with small branches from the splenic artery ; towards the middle of the organ, with the gastro-epiploic branches ; and at the p} lorus, with the superior pyloric artery. The arteria hepatica (c, figs. 250, 251.),which is the next largest branch of the cceliac axis, passes for a short distance outwards, and slightly forwards, from the axis or common trunk, to reach the commencement of the duodenum. It now runs almost vertically upwards between the two layers of peritoneum that form the gastro- hepatic omentum, and in front of the foramen of Winslow (though still with a 'slight incli- nation towards the right side), to end by being distributed in the liver. In this course, it gives off two branches, — the gastro-duodenal and the pyloric — both of which take an important share in supplying the stomach with arterial blood. Fig. 251. Arteries of the stomach. The cceliac axis, as seen ly raising the stomach, so as to expose the arterial brandies behind it. a, arteria coronaria vcntriculi ; c, arteria hepatica ; d, arteria gastro-duodenalis ; e, arteria gastro-epi- Ploica clextra ; f, arteria pancreatico-duodenalis ; g, arteria pylorica ; h, arteria splenica ; /, arteria gastro- e^iploica sin'stra. The gastro-duodenalis (r/, Jigs. 2 50 ,25 1 .) is the first and largest artery of these two. It leaves the hepatic vessel behind the duodenum, passing vertically downwards across the intestine to the lower border of its first portion. In this course, it gives off a few small branches to the neighbouring parts of the stomach and in- testine ; some of which twigs have been dis- tinguished as the inferior pyloric arteries. And at the inferior margin of the bowel, the gastro-duodenal artery bifurcates into two : — a large gastro-cpiploic, and a small pancrea- tico-duodenal branch. The gastro-epiploica dextra (^,^^.250,251.), the large vessel which continues the gastro- duodenalis, is so named from its situation be- tween those layers of the great omentum which descend from the stomach to form the " epi- ploon "or apron -like fold that covers the greater part of the intestinal canal. Beginning at the lower border of the duodenum, the artery runs from right to left, along the lower margin or great curvature of the stomach, and at a little distance from it, with what is usually a wavy or tortuous direction. In this course, it gives off branches which pass upwards on both surfaces of the organ ; as well as others of less importance, both upwards and down- wards, to the fatty and serous tissues of the omentum itself. And rather beyond the middle of the stomach, or towards its cardiac pouch, it ends by uniting with a corre- sponding branch, of smaller size, from the splenic artery. The panmeatico-duodenalis branch (/, fig. 251.) has precisely the situation and distri- bution which its name would imply. It runs between the duodenum and the head of the pancreas, lying in the concavity formed by the horse-shoe curve of the canal, or around the convexity by which the gland fits into this hollow. It gives off ramifications to both these structures, and ends by anastomosing with a branch, which comes upwards from the su- perior mesenteric artery and also occupies the same interval between the pancreas and the lower portion of the duodenum. The arteria pylorica (g, figs. 250, 251.), which is sometimes distinguished by the title of the pylorica superior from the smaller branches of the gastro-duodenal above allu- ded to, is generally given off from the trunk of the hepatic artery opposite to the upper border of the duodenum. More rarely it is derived from the commencement of its gastro- duodenal branch. In either case, it enters between the layers of the gastro-hepatic omen- tum, and runs in this fold, from right to left, along the upper margin or lesser curvature of the stomach, to join the coronary artery from the cardiac extremity of the organ. It gives off numerous branches to both surfaces of the organ. The arteria splenica (h, figs. 250, 25 1 .), or second branch of the cceiiac axis, has no direct.connection with the alimentary canal, until near its division into the terminal trunks by which it enters the spleen. Here it gives off a left gastro^iploic artery ; and STOMACH AND INTESTINE, 327 numerous small and short vessels, the vasa brevia. The gastro-epiploica sinistra (i,figs. 250,251 .) leaves the trunk of the splenic artery close to where this divides at the inner surface of the spleen. It passes downwards, forwards, and towards the right side, first lying for a short distance in the gastro-splenic omentum, and then entering between the layers of the great omentum which is continuous with this fold. It then runs along the lower border or great curvature of the stomach, to anastomose with the corresponding vessel on the right side. Like it, it supplies branches to both surfaces of the stomach. The vasa brevia are numerous small branches which come from the primary and secondary divisions of the splenic artery, and run in the gastro-splenic omentum to the cardiac pouch. Here they break up and anastomose with each other, as well as with the coronary and left irastro-epiploic arteries. The veins of the stomach are the superior pyloric, and the right and left gastro-epiploic. The vena pylorica superior receives and continues a large vein, which corresponds to the coronary artery, and takes a similar (but reversed) course along the lesser curvature of the stomach to the pylorus. It now passes upwards for a little distance, before opening into the vena portce (a, Jig. 281.) near its ter- mination in the liver. In other instances, it bends down to join the splenic vein. The vena gas/ro-epiploica dextra corre- sponds to its artery in the greater part of its distribution. It usually ends by emptying itself into the superior mesenteric vein, just before this forms the vena portce by joining with the splenic vein (e, Jig. 281.). The venn gastro-epiploica sinistra also runs with its artery, and joins either the splenic vein, or one of its primary branches. All of the foregoing vessels are characterized by the great freedom and frequency of their inosculations in every stage of their course from the aortic to the'portal trunks. This con- dition is especially well marked in the arteries. And, as ordinarily injected, the latter ap- pear to be both larger and more numerous than the arteries distributed to an equal bulk of most of the other structures of the body.* * Assuming this fact to be as true as it seems to be, it becomes interesting to inquire what peculiari- ties of the circulation may be presumed to be con- nected with it. Other things being equal, the pas- sage of a larger quantity of blood to and from an organ may be fairly supposed to be associated with a greater amount of that change which absorption or secretion there impress upon this fluid. Again, Yolkmann's researches have shown that the anas- tomosis of channels diminishes the resistance in their interior; — a diminution which, if not met by any counteracting circumstance, would increase the velocity of their contents. But the most plau- sible conjecture that can at present be offered is, that this increase in the number of these small ar- teries,— which have a distinctly muscular struc- ture, and are plentifully supplied with nerves, — has reference to that efficient and sudden control of their calibre which the varying exigencies of their capil- lary circulation would seem to imply. Their tortuous course, and their loose con- nection with the stomach, chiefly refer to the distention of this organ. For as the stomach expands between the laminae of peritoneum, it gradually straightens these vessels, and alters their position with respect to itself and to each other. The distal branches of the arterial and venous trunks perforate the muscular coat at different intervals, by twigs which unite with each other in the loose submucous areolar tissue, so as to form two broad and somewhat flattened networks : — one, which is composed of small arteries, and another, of veins. The vessels of the latter plexus are, as usual, both larger and more numerous than the corresponding arteries. Capillaries. — The arterial branches which leave the above sub-mucous network, to enter the dense muscular layer of the matrix of the stomach, divide here once or twice. And their ultimate ramifications, which have a diameter of about T-gfoffth to TTOTrtn of an inch, pass vertically upwards, along the sides of the tubes to their upper apertures, where they form a superficial network of capillaries. In passing Fig. 252. Plan of the vessels of the mucous membrane of the stomach, as they would be seen in a vertical section. a, arteries from the plexus occupying the sub- mucous areolar tissue; 6, superficial plexus of capil- laries occupying the ridges of the mucous mem- brane; c, veins passing downwards between the gastric'tubes ; d, capillaries between and around the tubes ; e, plexus of arteries and veins occupying the snbmucous areolar tissue. upwards, they also give off other capillaries ; which surround the tubes, at all parts of their height, with a second and deeper net- work. The meshes of this latter plexus are somewhat oblong, but less decidedly so than those of the capillary network of striped muscle; and are about T^th to T£otn of an inch in size. The capillaries which compose them are, on an average, little more than 7J^-yth of an inch in diameter. The more superficial netwoik is contrasted with this deeper one, not only in the fact that its capil- laries are about double the above diameter (or 328 STOMACH AND INTESTINE. ^.j^-th of an inch), but also in its meshes being nearly twice as close (or about T^th to ^^th of an inch). But the two plexuses inosculate so freely, as to be quite continuous with each other at the upper apertures of the tubes. As Fig. 253. Superficial capillaries of the mucous membrane of the human stomach, from an injected specimen. Mag- nified 70 diameters. a, ridges intervening between the sto mach -tubes ; b, capillaries occupying the ridges ; c, orifice of a stomach-tube. regards the form of the superficial network, it may be stated to correspond exactly with the intervals of the primary tubes. For the ridges which occupy the surface of the organ are all, as it were, moulded upon capillaries, the union of which forms what we may distin- guish as a primary network, that surrounds the aperture of each tube with a capillary loop. In Man,* however, this comparatively simple network is complicated by the addition of other meshes, which lie on either side of it, and just within the orifices of the tubes. In their shape and size, these closely resemble the loops beneath the ridges, and are, indeed, no way distinguishable from them except in their situation. Below, their diameter di- minishes, their loops elongate, and they finally merge into the general network which surrounds the tubes. It is from the large capillaries which com- pose the superficial network that the radicles of the veins almost exclusively arise. They begin as small vessels of about -ITOU^ °f au inch in diameter ; and by one or two suc- cessive unions of these* and their resulting larger branches, they soon attain a width of about 7iotn of an inch. They now pass vertically down the intervals between the tubes, to open into the flattened venous plexus which occupies the submticous areolar tissue. The general result of this arrangement on the circulation in the stomach seems to be, that the blood which has already traversed the capillaries of its tubes is passed on to its surface. Hence in respect to their situation and size, these superficial capillaries of the gastric mucous membrane offer a distant re- semblance to veins. This fact, as well as their connection, both with small arteries on the one hand, and with confluent capillaries on * In many animals the superficial network appears limited to this simpler form ; especially in the cardiac region, Avhere the intervals of the tubes are smaller. the other, renders it probable that the velo- city of their contents exceeds that of the blood which circulates in the capillaries of many other tissues. Such a peculiarity would admirably adapt them to that absorptive office which their mere situation on the cavitary surface of the organ indicates as one of their chief functions. Changes in the stomach during digestion. — The introduction of food into the healthy fasting stomach gives rise to two chief altera- tions in the organ. Its muscular coat is ex- cited* to movement. And, at the same time, its mucous membrane deepens from a pale to a bright pink colour f ; and begins to pour forth a liquid secretion — the gastric juice. Gastric juice. — An inquiry into the cha- racters of the gastric juice is opposed by many difficulties. For it is obvious that the properties of this or any other secretion can only be established from its examination in a state of perfect purity. While the situation and functions of the' stomach are such that, under natural circumstances, its secretion is necessarily mixed with many other substances. It is true that the bile often found J in the stomach during fasting is shut out from its cavity, during digestion, by the closure of the pylorus. But, on the other hand, the saliva, which generally covers the mucous surface of the empty organ, as a thin viscid layer with a superficial alkaline reaction, is swallowed at this period in much larger quantities; while the food itself forms an equally constant impurity. To such less avoidable sources of error are often added the alterations pro- duced by disease in the unhealthy individual, or by putrefaction or digestion in the healthy subject after death. And though even the most careful study of all these circumstances will scarcely explain the discrepancies and contradictions of numerous (and apparently faithful) observers in their accounts of the gas- tric juice, — still they evidently constitute con- ditions which, according as they are obviated, or noticed, or neglected, will respectively render any particular observations valid, or comparable, or utterly useless. § * See ante, p. 312. f Beaumont, Op. cit. pp. 94. et seq. I See ante, p. 315. § The above remarks form a key to the following historical summary of the more important observa- tions which have been made on this fluid ; as well as a reason why the author has reduced it to a mere enumeration,— such as will not, however, preclude a fuller subsequent reference, where this is required. Reaumur, in the year 1752, obtained an artificial digestive fluid from the stomachs of animals by means of sponges attached to strings (Me'm. de 1'Academie, 1752. pp. 705. et seq.). About 1780, Spallanzani (Ueber das Verdauungsgeschaeft. Leip- zig, 1785) adopted the same method; and also ex- amined matters which had been vomited. He thus determined the gastric juice to be a neutral, anti- septic solvent. He quotes Scopoli and Gosse to the same effect. Carminati (Untersuchungen ueber die Natur des Magensaftes, 1785) also deduced his results from substances vomited ; and found that it was only the acid fluid secreted after eating which possessed antiseptic and digestive powers. Several observers, however, — among whom were Viridet STOMACH AND INTESTINE. 329 Physical Properties. — Pure gastric juice is a structureless, limpid, and transparent fluid, of a pale straw colour. Its taste is slightly saline, and distinctly acid. And it has a pe- culiar faint odour, which is probably charac- fDe Prima Coctione, Geneva, 1692), Brugnatelli (Crell's Ann-ilen, 1787), and John Hunter (Animal (Economy, 2nd ed. p. 205. 1792)— had found that the stomach contained an acid. Macquart (Memoires de la Soc. Roy. de Medecine, 1786) stated this acid to be phosphoric in the paunch of Ruminants. Treviranus extracted the proventriculus of Birds with water : he thus, amongst other results, was able to confirm Hunter's conjecture, and regard it as lactic acid (Biologie, vol. iv. p. 358. 1814). Chevreul (Magendie's Physiologic, 1st & 2nd ed. 1825, vol. ii. pp. 11, 12.) analyzed a fluid obtained by volun- tary vomiting. He not only confirmed the presence of lactic acid, but announced the presence of the muriates of ammonia, potash, and soda; together with an animal substance soluble in water, but not in alcohol. In 1824, Prout led the way to a better knowledge of this fluid by an analysis of the contents of the sto- mach in Rabbits during digestion, in which he found hydrochloric acid and chlorides (Philosophical Trans - actions, 1824, pt. i. p. 45.). Dr. Children confirmed this statement from the gastric fluid of a dyspeptic patient (Annals of Philosophy, 1824, vol. viif. p. 68.). Leuret and Lassaigne, however, using this latter method, confirmed Chevreul as to the presence of lactic acid (Recherches physiologiques et chemiques pour servir a 1'Histoire de la Digestion. Paris, 1825.) Tiedemann and Gmelin excited the secretion of gastric juice by introducing stones into the stomachs of animals, and found hydrochloric acid on examin- ing the contents of the stomach after death (Die Verdauung nach Yersuchen. Leipzig, 1831). In 1833-4, Beaumont's unique case afforded specimens for three analyses ; by Dunglison, Silliman (Beau- mont, Op. cit. pp. 69. et seq.), and Berzelius (An- nuaire des Sciences chemiques, p. 282.). They all essentially corroborated Prout (Annales de Chemie, t. lix. p. 348.) ; as did Braconnot in 1835, with gastric juice from the sponged stomach of animals. \Vas- mann, in 1839, made some excellent experiments on artificial digestion with an infusion of pig's stomach ; but added little or nothing to our knowledge of the gastric acid (Nonnulla de Digestione. Berolini, 1839). Huenefeld, adopting Prout's method, obtained lactic acid (Chemismus in der Thierischen Organi- zation. Leipzig, 1840) ; a result in which, as well as in the cause of Prout's and Dunglison's view, Leh- mann either preceded or confirmed him (Physiolo- gische Chemie, 1840. Bd. i. p. 284.). Enderlin, however, who examined the digesting stomach of a beheaded criminal, and repeated Dunglison's process, reasserted its results (Liebig's Annalen der Chemie und Pharmacie, 1843. Bd. xlvi., p. 122.) In this year, Blondlot imitated Beaumont's case, by instituting fistulas in the stomachs of dogs; and announced biphosphate of lime as the acid principle (Traite Analytique de la Digestion. Paris, 1843). Lassaigne (Journal de Chemie, 1844, pp. 73. 183.) ; and Bernard and Barreswil (Comptes Rendus, 1844, t. xix. p.1285.) made use of the same method ; but denied the accuracy ot'Blondlot's chemical results in detail, and affirmed the presence of lactic acid. Pelouze corroborated some of their statements (Comptes Rendus, t. xix. p. 1227.) ; as subsequently did Thomson also (Philo- sophical Magazine, 1845, p. 419.). Schmidt next asserted that the active principle of the gastric juice was hydrochloric acid, modified by combination with the digestive principle; but did not detail the analyses on which this view was based (Annalen der Chemie u. Pharmacie, 1847, Bd. Ixi. p. 311.). Lehmann, in 1849, corroborated the lactic acid view, by examinations of gastric juice from tistulae (Be- richte der Gesell. der Wiss. zu Leipzig. Bd. i. teristic for each of the different* species of animals, like the smell of the blood from whence it is no doubt derived. Where, as is often the case, the gastric juice is mixed with saliva, mucus, or relics of the food, its appearances will of course differ from those above described. The froth of the saliva sometimes distinguishes this admixture. The mucus thus added is ropy or viscid, and ge- nerally presents scaly epithelium, which, toge- ther with its neutral or alkaline character, betray its origin from the mouth or oesophagus. Both it and the fragments of food are frequently deposited from the gastric juice, as a dirty flocculent sediment. And they may always be removed from it by careful filtration ; when the fluid loses its greyish, brownish, or turbid character. The specific gravity of the gastric juice was observed by Silliman to be about 1005*0. But from the condition of the specimen heexamined, and the mode of weighing^ he adopted, very little reliance can be placed on this state- ment. Lassaigne J also made direct obser- vations with the same view, and found that the irritated empty stomach poured forth a fluid of sp. gr. lOOl'O ; while that secreted on the contact of flesh was 1005*0, and with bread lOlO'O. But it must obviously be very difficult directly to determine the specific gravity of such a fluid, in the small quantities in which it is generally obtained. The per-centage of solid contents is more easily estimated. — Tiedemann and Gmelin rated it at T95 in the gastric juice of a dog who had been made to swallow small pieces of limestone ; and at P6 in that of a horse. Berzelius gives it at 1*27 in the specimen sent him by Beaumont; Lassaigne at T32, and Blondlot at TO, from the gastric fistulae of dogs ; Frerichs (appa- pp. 100. et seq. ; and Op. cit. Bd. i. s. 97.). And Frerichs about this time came to the same conclu- sion (Wagner's Handwoerterbuch der Physiologic, vol. iii. p. 815.) from similar experiments. But this comparative unanimity in favour of lactic acid was not destined to last long. In 1851, Huebbenet for the first time found a simple method of preventing that admixture of saliva which had hitherto rendered the gastric juice obtained in such experiments with fistula? an impure secretion. This he did by obliterating the ducts of the larger salivary glands. And the researches which Bidder and Schmidt instituted upon the gastric juice thus pro- cured seem at length to have established, that it is the hydrochloric which constitutes the proper acid of the gastric juice. [In preparing the greater part of this essay for the press, the author found it impossible to procure a copy of Bidder and Schmidt's valuable Essay ; and was hence only acquainted with such portions of it as are mentioned in Lehmann's (Physiologist-he Chemie, vol. iii.) recent work ; in the reports given of Huebbenet's Dissertation by Scherer and Valen- tin, in Canstatt's Jahresberieht (1852, Bd. i.) ; and by Funke in Schmidt's Jahrbuecher (1851, p. 275.).] * At any rate the author's observations tend to show that this is the case in Man and many animals. Human gastric juice is stated by Dun- glison (Physiology, vol. i. p. 503.) to smell of hydrochloric acid. And Beaumont (p. 76.) asserts, that it tastes like this acid in a state of dilution. f Beaumont, Op. cit. p. 72. J Loc. cit. pp. 183. et seq. 330 STOMACH AND INTESTINE. rently from dead animals) at 1'72, 1'80, M5, after feeding with hay, bones, and peppercorns respectively; Lehmann at an average of 1'4 ; Bidder and Schmidt at 2'694 in the gastric juice of a dog with deligated salivary ducts, 2'883 in another dog in whom they were free, and 1-385 from a sheep. These latter high numbers indicate that, whatever may be the influence of an admixture of food or saliva in increasing the residuum of the gastric juice, it is more than counterbalanced by the loss which attends the analysis of small quantities. The first of these three quantitative analyses by Bidder and Schmidt I have made the ba- sis of a calculation *, according to which the specific gravity of the gastric juice would be 1003'3, — an estimate that tolerably agrees with the observations of Lassaigne and Silliman. The quantity of the gastric juice is even less accurately established. From Beaumont's experiments, it would appear that at least eight ounces may be secreted in an hour. It is, however, not impossible that ten times this amount may be poured out during the digestive process. For Bidder and Schmidt's observations on animals give an average of about — i^ th of the weight of the whole body per hour, with a maximum of ^Vtn m the same period. But it is probable that the latter proportion exceeds that which could be secreted by a human being f in the same space of time. Chemical composition. — In inquiring into the chemical composition of the gastric juice, it will be convenient successively to consider its acid, its saline, and its animal constituents. The gastric acid. — Although this obvious and unmistakeable character of the gastric juice has been recognised for more than 150 years, yet the nature of the acid on which it depends is probably still regarded as un- certain. An impartial and searching criticism of all the numerous and conflicting analyses that have been made would far exceed the limits of this essay: — even had the author (what he has not) the abilities and leisure necessary to such a task. The reader will therefore only expect such a sketch, as may include some of the chief facts which justify us in preferring, if not in adopting, one par- ticular view. Not to mention those exceptional instances in which acetic, butyric, or other acids, have been found in inefficient quantity in the con- tents of the stomach, there are at least three views of sufficient importance to demand * This calculation is founded on a method sug- gested by Schmidt, and quoted by Lehmann (Op. cit. Bd. iii. pp. 4, 5, 6.). 1 have assumed that the condensation of the ferment on solution equals that of albumen ; that the chlorides of calcium and am- monium stand about midway between those of po- tassium and sodium in this respect ; and that the hydrochloric acid occupies no bulk at all. On these suppositions, the 26'938 grains of residuum would take the space of 23-617 grains of water ; whence 1000—23-617 + 26-938 = 1003-3. f In a person of average weight, the above pro- portion of ^th of the whole body would correspond to a secretion of about seven pints (nearly one gallon) of gastric juice in an hour. some notice. The first of these regards the gastric acid as the hydrochloric : the second as the lactic. While the third attributes the acid- ulous character of the secretion to the presence of a salt, the acid phosphate — or, as it is some- times incorrectly termed, the superphosphate* — of lime. The latter view, which denies the presence of a free acid, is the more recent of the three. It rests solely upon the statements of Blondlot f; from whose writings we select some important details, which are directly contradicted by the concurrent testimony of other chemists, and even by his own later researches. According to him, the gastric juice is precipitated by lime, does not act upon chalk, and contains no chloride of calcium. He also states (or rather implies) that biphosphate of lime is decomposed by incineration, so as to leave a neutral residue. Each of these statements is met by Lassaigne, Huenefeld, Melsens, Dumas, Bernard, and various other authorities, with a direct denial. And in a more recent Memoir, Blondlot himself lays especial stress upon the presence of a large quantity of chloride of cal- cium, the absence of which salt he had previously insisted on.{ After these remarks, it is un- necessary to detain the reader by any further consideration of the various other errors — qualitative as well as quantitative — which in- validate the chemistry of this observer. But it is impossible to make these necessary allu- sions to Blondlot's analyses without passing a tribute to his talent, in devising an operation to which we owe all the brilliant experiments that have lately done so much for the physio- logy of digestion. Of the two remaining views, the parti- sans of each were, until lately, so equal in number, in repute, and in the validity of their arguments, that few physiologists could decide in favour of either : and those who could not suspend their judgment, were probably beginning to believe in both. On the side of lactic acid was the united testimony of Chevreul, Lassaigne, Thomson, Lehmann, Payen, Bernard, and Frerichs ; who had all verified its presence in gastric juice, sometimes when unmixed with food. While against the analyses of Prout §, Dunglison, Braconnot, Tiedemann, and others — in which hydrochloric acid was either lost from the * The formula of which is CaO, 2 HO, P2 O5. t Loc. cit. j Compare Op. cit. pp. 246. 250., and Comptes Rendus, t. xxxiii. p. 118. § This allusion to Dr. Front's analyses may seem to require some explanation ; the more so, that they have sometimes been misquoted. He analyzed the gastric juice of rabbits who had been fed shortly before death. The contents of the stomach were filtered, and divided into four parts. The first was evaporated to dryness, and ignited. The second was supersaturated with potash, and similarly treated. The third was exactly saturated with the same alkali of known strength. In the case of the first two portions, the saline ash remaining after ignition was dissolved in water, and tested with nitrate of silver for hydrochloric acid. It was presumed that the first method would give the amount of fixed chlorides present j the second, the total amount of STOMACH AND INTESTINE. 331 residuum, or found in the distilment, of the gastric juice — they * brought forward the fact, that towards the close of the process of distillation, the fixed lactic acid was capable of displacing the volatile hydrochloric from the salts in which it had been formerly com. bined ; leaving lactates and lactic acid, in a thick acidulous residue of a syrupy consistence. They added, that this late appearance in dis- tillation (as shown by nitrate of silver and peroxide of manganese) proves the absence of the free acid ; as does also the precipitate effected in gastric juice by oxalic acid, — a precipitate which would not occur in water containing but s^th of hydrochloric acid. To this one might have answered, that such a displacement of hydrochloric acid could scarcely have occurred in any of these analyses. Dr. Prout examined in vain for organic acids. And just as he expressly af- firms, so others imply, their absence. While Dunglison -j- and Berzelius found that the re- siduum contained a large quantity of chlorides. And if it be difficult to suppose the chlorides of the gastric juice sufficient, both for a large distilment of acid, and a still larger residuum of salts, — it is even more difficult to imagine (with Lehmann J), that the chloride of cal- cium alone can yield the former, and yet also appear in the latter. The absence of the ordinary reactions of hydrochloric acid is, indeed, explained by a theory of Schmidt's, which will be noticed again hereafter, and according to which the acid is in some degree fixed and retained by its chemical combination with the organic prin- ciple of the gastric juice. He shows that, if a solution of nitrate of silver be added to this secretion, it throws down a precipitate, which consists of chloride and organic matters; while conversely, it leaves some silver in the clear supernatant fluid. But such a fact scarcely requires the aid of the above theory. The way in which the affinity of even small quantities of organic substances can disturb various chemical processes, offers a well- known analogy to this retarded precipitation. And without some such an action really ob- hyolrochloric acid, as well free as combined. The third method would allow of the estimate of the free acid. And this, together, with the fixed hydro- chlorates of the first method, subtracted from the total of the second, would leave the quantity com- bined with the volatile alkali ammonia. He thus found, that rather more than half the chlorine present was combined with hydrogen, in the form of free hydrochloric acid, while, of the remainder, nearly half was united with ammonia, the rest with potassium and sodium. A fourth portion was exa- mined in vain for an organic acid. And other salts, »uch as sulphates and phosphates, were only found in very small quantity. * Aided and confirmed by the observations of Blondlot (Loc. «*.), Huenefeld (Chemismus in der Thierischen Organization, Leipzig, 1840, p. 207. et *eg.), and others. t With the " astonishing quantity " of chloride of silver obtained from the distilled liquid by Dun- glison, there ought to have been at least half as much lactic acid in the (apparently uninjured) re- siduum. t Compare Op. cit. vol. i. p. 98. and vol. ii. p. 43. tained, the non-precipitation of dissolved albu- men by gastric juice would (as Blondlot indeed assumes) disprove the presence of both lactic and hydrochloric acids in this fluid. The analysis of Enderlin, however, carried the investigation a step further, by distinctly asserting the presence of hydrochloric acid in the residuum of the distillation.* And Bid- der and Schmidt's recent experiments seem quite conclusive, both as to the presence of this, and the absence of lactic, acid.-f- These observers avoid distillation, and treat the fresh gastric juice, previously acidulated by nitric acid, with nitrate of silver ; so that the pre- cipitate is free from all organic matters. To the supernatant liquid, they add hydrochloric acid, so as to remove all excess of silver ; and then determine its bases by evaporation and ignition. These they find insufficient to neu- tralize the chlorine of the precipitated chlo- ride. And on saturating a quantity of the same juice with potash, baryta, or lime, they find that the amount required for its neutrali- zation is exactly equivalent to the deficiency observed in che previous analysis. But this leaves us with two gastric acids, the hydrochloric and the lactic. Hence three questions suggest themselves. — (1.) Are they present together ? (2.) Do they substi- tute or replace each other? Or (3.) is the lactic acid a mere secondary and accidental product ? Even since Bidder and Schmidt's analyses, Lehmann has again answered the first of these questions in the affirmative ; having found both acids together in a quantity of gastric juice collected from 14 dogs. The second and third questions cannot at present be re- plied to. As regards the second, we have no valid proof that the species of the animals examined, their health, or even the nature of their food, ever effects any such quali- tative alteration in this secretion. In respect to the third, we may point out, that the vari- able (and often large) quantity of lactic £ acid is precisely what might be expected, supposing it to be a secondary production. And, according to Lehmann, the particular variety of lactic acid seen in the stomach is that produced by the fermentation of sugar, and not that obtained from the fluid of muscle. This fact has induced me to conjecture, that the lactic acid thus observed can scarcely be directly secreted from the blood. But it must remain for future experiments to decide, whether its absence in the later (and appa- rently exact) analyses of Bidder and Schmidt, was due to the exclusion of saliva, to the fresh state in which the gastric juice was examined, to its careful separation from all food and peptone, or, finally, to the avoidance of the process of distillation. Still, waiting * Lehmann (vol. i. p. 97.) urges against this ob- server, that, in a previous analysis, he had failed to find carbonate of soda in the ash of the blood : — an argument which seems somewhat invidious as well as inconclusive. f Lehmann, Op. cit. vol. iii. p. 331. j Compare Lehmann, vol. ii. p. 42. ; vol. iii. p. 33, 332 STOMACH AND INTESTINE. the results of such a laborious inquiry, there seems little doubt that we ought to regard the balance of evidence as inclining decisively towards a single gastric acid, and that acid the hydrochloric. * Whatever the number or nature of the sub- stances to which this acid reaction of the gastric juice is due, there can be no doubt as to their source : — namely, the blood. And it is to a derivation of acid from some of the constituents of the latter fluid that we must refer the important fact established by Dr. Bence Jones : — namely, that, during diges- tion, the healthy urinary secretion loses that acidity which is proper to it at other periods. Salts. — As regards the salts of the gastric juice, we can only refer to the accurate analyses alluded to above ; — which, while they confirm the large quantity of chlorides mentioned by most observers, exhibit rather less of the chloride of ammonium than the united (but rather vague) statements of many observers would have led us to expect. The details of an analysis of the gastric juice may be best comprehended (if not ex- plained) by placing them side by side, with a similar quantitative examination of the liquor sanguinis. The following tablef exhibits such a comparison, for a thousand parts of both fluids. Liquor Gastric Sanguinis. Juice. Water - - - 903- 973-2 Animal matters - 88'5 17'0 Mineral substances - 8'6 9-8 Chlorine 3'6 5-6 Sodium --- 3-3 1-2 Potassium (in dog, -2 ?) -3 -6 Phosphoric acid - '2 '6 Phosphate of lime - -3 1-2 Phosphate of magnesia *2 *2 (Lime corresponding to •624 Ca. Cl.) - '3 1000-0 1000-0 Hence, while most of the blood-salts are present in increased quantity in the gastric juice, the chloride of sodium is so greatly di- minished, as to lower the total saline contents of this secretion below those of the liquor * It is only many months after writing the above lines that Bidder and Schmidt's admirable treatise (Die Verdauungssaefte und der Stoffwechsel) has com§ into my hands. From it I may translate the fol- lowing paragraph (p. 44 ) : " The result of eighteen corresponding analyses was, that pure gastric juice of carnivora, after eighteen to twenty hours' fasting, contained free hydrochloric acid only, without a trace of lactic or any other organic acid : while the gastric juice of herbivora contains, with free hydrochloric acid, small quantities of lactic acid ; which may, however, be referred to their more amylaceous food." f Here I have calculated the composition of the gastric juice from the purer fluid of Schmidt's first dog. That of the liquor sanguinis, which is quoted from Lehmann (vol. ii. p. 153.), may be safely (Id. p. 179.) extended to this animal. To facilitate comparison, both are simplified to one place of deci- mals. And for the same reason, the phosphate of lime in Schmidt's analysis has been assumed to be the biphosphate, and divided into phosphoric acid, and neutral phosphate. sanguinis. While the amount of its hydrochlo- ric acid is so great, as not only to compensate this loss, but even to raise the total of its mineral constituents above that of the liquor sanguinis than before. The origin of this acid is obvious. Its mere quantity is sufficient to refer it to the chloride of sodium, which is the most plentiful chloride of the parent fluid. And the remarkable diminution in the sodium of the secreted fluid further confirms this view. Indeed, it is difficult to avoid noticing, that many of the differences between the salts of the two fluids might be included in some such hypothesis as the following: — (1.) a rapid transudation of the blood-salts generally, followed by their concentration through ab- sorption of part of their water of solution ; (2.) a decomposition of about half of the chlorides, probably of the chloride of sodium*; (3.) a return of the base of this salt into the blood. Organic substance, or Pepsine. — The addi- tion of alcohol to pure gastric juice, or to a watery infusion of stomach, causes a white flocculent precipitate ; which, when dried at a low temperature, forms a much less volumi- nous mass, of a yellowish grey colour, and a somewhat gummy appearance. This substance reddens litmus, and is soluble in cold water ; but may be again precipitated from its aqueous solution by alcohol. Its ultimate analysis yields sulphur and nitrogen, together with car- bon, hydrogen, and oxygen. But we neither know the exact proportions in which all these elements are present, nor the manner in which they are combined: — and may even doubt, whether its composition is really quite defi- nite and constant in different specimens. Two analyses of this precipitate have how- ever been made :— one by A. Vogel f , of the extract of Pig's stomach ; and one by Bidder and Schmidt^ of the pepsine obtained from pure gastric juice. They are as follows : — Pepsine. Schmidt. 53-0 6-7 17-8 Vogel. Carbon - 57 -72 Hydrogen - - 5*57 Nitrogen - - 21-09 Oxygen<( + other ele- ments, and loss) 16*06 22-5 Of these two analyses, the latter is pro- bably the more correct one. It offers us a composition closely resembling that of the various protein compounds, from which it * Such a decomposition would obviously present many analogies to an electrolysis. But, at present, we should hardly be justified in naming it after this process. That the acid and base are unloosed and separated is certain. But I think no one who has carefully studied the phenomena of current affinity would like definitely to refer the above decomposi- tion to this cause in the existing state of our know- ledge. We may, however, notice, that both the quantity and quality of the chloride of sodium would render it more susceptible to electrolytic action than any other of the salts present in the liquor san- guinis. f Simon's Beitraege, Berlin, 1843, p. 168. ; Ann. der Pharmacie, 1839, Apr. p. 36. I Op. cit. p. 46. STOMACH AND INTESTINE. 333 differs chiefly in containing about 2 per cent, more nitrogen. The addition of a few drops of dilute muriatic acid to a solution of this precipitate in cold water, constitutes a liquid which possesses energetic solvent powers over ordi- nary animal food. Hence the organic sub- stance itself has been termed pepsine (Wtfrc. cit. I Kotlliker, Valentin, Todd and Bowman, and others. of intestinal tubes by losing their oval gastric cells. Hence all these circumstances throw great doubt on the alleged solvent powers of the in- testinal juice ; and render it impossible for us at present to decide what is the exact digestive office which it fulfils. And we are almost as ignorant of its quantity as of its quality. But it is probably secreted by the small intestine in much greater amount than by the large. According to Bidder and Schmidt, it is poured out most freely about five or six hours after a meal. And drinking soon increases its amount, without causing any con verse diminution of its concentration. Its strongly alkaline reaction may be conjectured to have some relation to that large quantity of acid, which is appa- rently withdrawn from the chloride of sodium contained in the blood of the stomach, in order to furnish the gastric juice. Indeed, a liberation of soda or some other alkaline base, appears almost implied in that of the hydro- chloric acid. But hitherto no exact analysis has informed us to what particular substance the alkaline character of the intestinal juice is immediately due. And it is only after a careful comparison of the composition and quantity of this secretion with those of the less alkaline bile and pancreatic fluid that we should be entitled to conjecture, how far the neutralization* of the acid peptone constitutes a special function of the intestinal juice. Still, from the great extent of secreting surface which yields this juice, we can hardly doubt, that it takes a large share in this neutralizing process, which was formerly attributed chiefly to the bile. It probably thus forms part of that cycle of alternate decomposition and recomposition, which appears to be under- gone by the chloride of sodium. The vascular arrangements by which these intestinal tubes are supplied with blood, so closely resemble those of the stomach -tubes, as to Vender any special description of them superfluous. Like the tubes themselves, the vessels are chiefly concerned with secretion. But while we are left in doubt as to the pre- cise degree or kind of that absorptive function which the vessels of these tubes possess, in common with those of all such mucous sur- faces, we are perhaps justified in attributing a special capacity of absorption to the plexus of large capillaries, which here, as in the former organ, lies immediately beneath the epithelium, around their open extremities. The loops of this superficial plexus are generally more simple than in the stomach. They encircle the mouth of each tube with what is often only a single ring of capillary (b fig. 258.) ; except in the neighbourhood of the solitary or agminate follicles, where they resemble the analogous gastric vessels in forming more complex meshes (a Jig. 20.) They communicate very freely with the capil- * It is impossible to state whether this neutra- lization of the gastric acid takes place during the sojourn of the gastric juice in the intestine, or after its absorption into the capillary veins around the canal. 350 STOMACH AND INTESTINE. laries of the neighbouring villi. And the venous radicles of these latter processes usually unite with the branches formed by their con- tFig. 2.58. Capillaries occupying the surface of the mucous mem- brane of the small intestine ; as seen on examining an injected specimen by reflected light, with a mag- nifying power of about 50 diameters. a, b, capillaries around the orifices of the intes- tinal tubes. At a their meshes are more numerous and complex than at b, where they are almost re- duced to single capillaries ; c, calibre or cavity of the intestinal tube. flux in a small vein ; that sinks vertically through the mucous membrane, to join the sub-mucous plexus which gives origin to the portal vein. Villi. — The interior of almost all the small intestine presents to the naked eye a texture very like that of velvet. For it is soft and shaggy : yields readily to pressure : and, on close examination, is evidently composed of innumerable short filaments, which are placed more or less vertically to the general inner sur- face of the tube. These filaments, — the dense arrangement of which on a common surface causes this general velvety appearance, — are thence usually named villi. Their form, and their situation, or office, might also be denoted by the name of intestinal or chyliferous papilla. We have seen that, in the stomach, the con- fluent ridges intervening between the tubes are here and there raised into slight projec- tions. These are rendered more prominent by artificial injection of the subjacent vessels, or even by that afflux of blood which ordi- narily attends the digestive act. In the pylo- ric extremity of the organ, these projections become more distinct. And just at its termi- nation, some of them often assume the form of bluntly triangular and flattened folds. In the upper part of the duodenum, the villi begin; by processes which somewhat resemble the gastric elevations just alluded to, and occupy an analogous situation with respect to the intestinal tubes. At first, they may be described as flattened folds, the out- line of which is a very obtuse triangle, that has a broad base about four or five times its height (T£otn of an inch). In the lower part of the duodenum, this rudimentary form for the most part disappears ; and the villi, which are still more or less flattened, have about twice the length, and half the width, of those present in the upper part. But it is in the upper part of the jejunum that they attain their greatest number ; being placed so closely together that their interstices scarcely Fig. 259. Villusfrom the upper part of the jejunum, as seen in the fasting state. Magnified 140 diameters. a, epithelium of the villas ; 6, parenchyma or sub- stance of the same. equal their own bulk. Here they also acquire their maximum length, which ranges from about ^yth to ^th, or even T^th or T\th of an inch. Their form, however, is still that of a flattened cone (compare Jig. 259. and Jig. 257. p. 347.) ; — the breadth of the base of which is about Jth, and the depth about -j^th, its height. In the remainder of the intestine, the length of the villi gradually recedes to that which they possess in the lower part of the duodenum ; while their number also diminishes to a some- what smaller extent. Throughout all this extent, the shapes and sizes of contiguous villi often present great varieties. But as a rule, the lower we descend in the examina- tion of the intestine, the greater is the number of cylindrical- forms we meet with. While towards the extremity of the ileum, the gradual diminution of their size renders many of them scarcely more than ^^o^1 °f an mch in dia- meter. The villi cover the whole surface of the mucous membrane of the small intestine, in- cluding its valvulae conniventes ; and they extend to the free margin of the valve which marks the commencement of the caecum and colon. The only exception to their pre- STOMACH AND INTESTINE. 351 sence occurs in the agminate follicles, or " I'eyer's patches." Here they are absent over the several follicles which together form each patch ; and become short, (0, Jig. 272, p. 358.) blunt, irregular, or even confluent, where they occupy their interstices. We have seen that each of the valvulae conniventes is a doubled fold of membrane, separated by a layer of areolar tissue. While the minute intestinal tube may almost be re- garded as a mere membranous lamina, which is involuted so as to surround a cylindrical cavity, and is packed in a sparing fibrous invest- ment. But the villus constitutes, as it were, a solid process of the mucous membrane. In accordance with this structure, it consists of an epithelium, a basement membrane, a stroma or basis of fibrous tissue, unstripecl muscle, and numerous blood-vessels. And in ad- dition to these constituents, which may be found under various modifications throughout the svhole intestinal mucous membrane, the interior of each villus encloses one or more branches of the lacteal vessels which con- tain the chyle. The epithelium of the villi (a, fig. 259. and a, jigs. 264, 265,266.) consists of a single layer of cylindrical cells, which, — as regards size, shape, and general appearance, — closely resemble those seen on the ridges between the tubes of the stomach. They are, how- ever, even more delicate in their structure, as well as more conical in their shape. Fis. And their contents are, even during fasting, somewhat darker and more granular. The nucleus, which occupies the same situation in both these varieties of cylindrical epi- thelium, contains a single bright spot, or nucleolus : in rare instances, this appears to be double. The basement-membrane (at b, Jig. 260.) does not require any special mention. As in the gastric ridges, it is very closely at- tached to the subjacent structures, espe- cially to the vessels. But its continuity with the similar structure forming the in- testinal tubes sufficiently indicates that it is really a distinct membrane. And it is often demonstrated to be such by the action of water ; which, after transuding it from the outer surface, raises the membrane, in the shape of a delicate transparent bulla,from the general mass of the villus beneath. The blood vessels of the villi are extremely numerous. Small arteries, (a a, Jig. 260.) of about T^^th of an inch in diameter, pass between the in- testinal tubes. The base of each villus re- ceives one, two, or more of these, according to its size. They now pass upwards in the substance of the process, at some dis tance from its surface; and rapidly diminish by giving off numerous capillaries, into which their own trunks entirely merge at about the middle of the height of the villus. The ultimate capillaries themselves (c ct 260. Vessels of two villi, injected. Magnified 100 diameters. a a, arteries entering the basis of each villus near its centre; vv, veins seen in the same situation; c, capillaries lying immediately beneath the limitary membrane ; d, tortuous capillaries occupying the free extremity of one villus ; b, limitary or basement membrane of the villus, denuded of its epithelium Jig. 260.) are, on an average, about £rd of the above diameter. They constitute a net-work, which lies directly under the basement mem- brane ; and covers the whole villus so thickly, as to give it a vivid red colour in injecte'd specimens. The shape and complexity of this usually such, that the length of its meshes is five or six times their width. The capillaries are distinguished by their being apt to ex- hibit a wavy and tortuous course (d, Jig. 260.) which often [causes their real length greatly to exceed 'that of the villus itself. network is liable to great variety ; but is This character is especially marked at the 352 STOMACH AND INTESTINE. free extremity of the villas: — to the contrac- tion of the muscular layer of which it would appear to be chiefly, though not wholly, due. The veins (vv,fg.260.) come off from this network by the gradual union of capillaries in the upper half of the villus, so as to form two or more venous trunks. These are usually about double the width of the corre- sponding arteries : they run at a distance from them ; and often lie rather nearer to the surface of the villus. Below, these trunks become confluent in the single vein of the process; which, passing vertically downwards, terminates by joining one of the numerous veins belonging to the venous plexus around the orifices of the intestinal tubes. And this latter network also joins that of the villus by such numerous communications, that the two might almost be regarded as merging into each other. The substance which forms the ground- work or basis of the villus resembles, to some extent, that of the gastric mucous membrane ; — the morphological consti- tuents of which we have already seen to be indistinct, except at the bottoms of the tubes. It rarely presents any definite struc- ture. Sometimes, however, it is faintly striated. And occasionally this appearance is so marked, as to approach a fibrous character. In this re- spect, it resembles the papillae of the skin and tongue ; — and, especially, those secondary projections which stud the fungiform papillae of the latter organ, the basis of which contains no yellow elastic fibres, but is almost homo- geneous, and often indistinctly granular. Mixed with this indistinctly fibrous tissue are numerous delicate cytoblasts or nuclei (b, Jigs. 259, 261, 262, 263.). The larger of these attain the size of coloured blood-cor- puscles ; while the small merge into granules by increasing minuteness. The exact re- lation of these to the basis of the villus is un- known. Their general effect is to communicate to the whole villus a more or less mottled and granular aspect. This appearance (which we shall find is increased during the period of intestinal digestion) often obscures, not only the vague fibrillation just alluded to, but the whole of the structures which lie beneath the basement membrane. As regards the lacteals of the villi, few anatomical details have been more disputed than those which relate to the commence- ment of the chyliferous absorbents within the substance of these processes. The pro- gress of microscopical research has, how- ever, reduced the controversy within very narrow limits ; and promises at no distant date, to end it by a final decision. At pre- sent, almost all trustworthy observers agree in the statement, that each villus receives by its base a single (perhaps sometimes a double) branch of the lacteal system. It is only as to the further course of this vessel that opinions differ. Many affirm it to be continued up the villus as a single tube, which ends near its apex by a blind and often some- what dilated extremity. Some authorities modify this view for the broader villi, by stating the canal to be double — either as a single loop, or as a bifid and somewhat tor- tuous tube. While others find that the cen- tral and simple lacteal canal ends by branching into a network of more or less complex cha- racter, like that of the capillaries. The first of these statements will at any rate apply to many of the villi. Numerous observers have verified its accuracy for the human subject. And it is not difficult to obtain distinct evidence of its truth in some other Mammalia. Amongst these the sucking Rabbit and Calf are especially suitable for examination. If proper care be taken to examine the chyliferous villi of these ani- mals instantly after death, with the aid of suitable fluids, we may easily convince our- selves of the presence of a single large lac- teal tube, with distinct walls, like that repre- sented in the annexed figure (fig. 26 1.). Such Fig. 261. b d d b Two villi, denuded of epithelium, with the lacteal vessel in their interior. From the Calf. Magnified 350 diameters. (After Koelliker.} a, limitary membrane of the villus ; b, matrix or basis of the same ; c, dilated blind extremity of the central lacteal ; d, trunk of the same. single lacteals are generally very large, having a diameter which often amounts to about one- third or one-fourth that of the villus itself; and exhibit a dilated blind extremity, (c,jig. 261.) which nearly doubles their width, hi man, according to Frerichs *, they are scarcely more than one-half or two-thirds of this size. But it remains to be considered whether this * Op. dt. p. 751. STOMACH AND INTESTINE. 353 statement excludes the possibility of a net- work, such as has been affirmed to exist by Krause and others. Koelliker, in whose ad- mirable work * the reader will find a copious analysis of the latest observations on this subject, sums them all up very impartially by acknowledging, that, although he has never been able to see a trace of such ramifications, still he cannot venture altogether to deny their existence. On the contrary, he thinks *it pos- sible that the above simple mode of commence- ment,— which certainly holds good for the cy- lindrical villi, — ma) be exchanged, in the larger of these processes, for one involving the pre- sence of a greater number of lacteal canals, or the absence of such blind extremities. But in conceding this much, Koelliker points out — what Valentin -f- seems previ- ously to have suspected, — the facility with which a striated arrangement of the dark fatty molecules within the chyliferous villus may be mistaken for lacteal vessels. Nay more, even the chyle of the central canal sometimes separates by coagulation into striae, which closely imitate a branched network. We may add, that, in the various observations which have been made on executed criminals, the possibility of error has probably been in- creased by the distended state of the vascular and lacteal canals contained within the delicate structure of the villus. Whatever be the case as regards these conjectures, it seems to me that the large simple tube, and the minute network, are far too unlike to be regarded as mere degrees of development of the same structure in differ- ent villi. In like manner, the simple loop of lacteal seen by Henle just beneath the base- ment membrane is suspicious, not only from its situation, but also from a fact noticed by Valentin and Remak, — that the central canal sometimes coexists with it. And when we add to the foregoing remarks, that the majority of observers have been unable to see any such ramifications, it will seem difficult to avoid concluding, that each villus probably contains a single large lacteal, which occu- pies its centre, and ends by a blind extremity. The muscular constituent of the villus was first discovered by Bruecke, and has since been verified by Koelliker in many Birds and Mammals. Its shape is that of a thin hollow cone, which closely imitates the form of the villus enclosing it. Hence, from whatever side it is examined, it may be seen as a double lon- gitudinal layer ; which is placed immediately around both sides of the central lacteal ; and lies so deeply within the villus, as to be beneath its vessels, as well as much of its granular basis. It is more distinct in the lower part of the villus, and in the larger flat specimens ; but is easily obscured by oil globules, nuclei, or pig- ment. The nuclei of its fibre cells are best seen on the addition of dilute acetic or nitric acid, when they assume their ordinary charac- teristic appearance. The action of this contractile apparatus during life is at present unknown. Derived, as it no doubt is, from that general expanse of Fig. 262. Supp. , cit. p. 1GO. et seq. . cit. p. 684. VUlus denuded of epithelium, treated iciih acetic acid. From a young kitten. Magnified 350 diameters. (After Koelliker.) a, outline of the villus ; b, nuclei beneath this ; c, nuclei of the unstriped muscle ; d, roundish nuclei in the centre of the villus. unstriped muscular fibre which pervades the whole mucous membrane of the alimentary canal, one can hardly avoid ascribing to it a function which is more or less similar, — if not indeed co-ordinate, — with that of the general stratum. That this function is in some respects related to the static or passive mechanical cir- cumstances of the mucous membrane, has already been conjectured (p. 325.) in speaking of the stomach. And the little we know of the ordinary action of the analogous unstriped element in the skin, rather confirms than con- tradicts such a supposition. But its pecu- liar position with respect to the end of the lacteal trunk in the centre of the viilus, — to which it forms a kind of muscular and contractile envelope — has given rise to the suspicion, that it effects the propulsion of the chyle contained in this canal. How far such a process really obtains must be determined by future research, which ought especially to notice the precise con- nection of this muscular stratum with that of the mucous membrane generally. In the meantime, we may notice that, as Koelliker justly remarks, an active propulsion by these longitudinal fibres would imply their alternate contraction and relaxation.* But, assuming * He also adverts to their apparent want of nerves, and to the essential independence of organic muscle of all but mechanical irritations. However A A 354- STOMACH AND INTESTINE. this to occur, it is evident that such a remittent contraction would not destroy the claims of the absorptive act itself to be considered the chief force which propels the chyle. For in any case, the muscular apparatus would but limit and remove that diatention of the lacteal which absorption had previously ef- fected. It would thus, as it were, merely re- gulate and transfer the mechanical force of the latter act ; so as to modify it, either constantly, or at definite intervals of time. Some observers have attempted to verify the action of this delicate muscular apparatus dur- ing life. Gruby and Delafond first instituted such observations on a variety of domestic animals j and they have since been repeated by Bruecke and Koelliker. AH of these authorities agree in remarking an alternate shortening and elongation of the vilius : — a change of form which is so rapid and marked, that there need be little hesitation in attri- buting it to a corresponding contraction and relaxation of these unstriped fibres. But the phenomena seen in the course of such vivisections cannot be safely accepted as those of the healthy animal in its natural state. * Such a caution is still more applicable to those contractions by which the villi share in that irregular movement of the intestine already described as a kind of rigor mortis. On exposing the villi of an animal soon after death, they gradually become shorter and Fig. 263. Villi contracted and shortened so as to offer circular or transverse wrinkles. From the small intestine of the dog shortly after death. Magnified 100 diame- ters ; and examined by reflected light. wider ; at the same time that their surface is generally thrown into circular transverse general this view of the action of unstriped fibre, I must confess myself very reluctant to accept it on its present evidence. * for,— to say nothing of the pain, the irritation, wrinkles or folds. A more minute examination shows that these folds consist of epithelium, which has separated from the basement mem- brane at the points that correspond to the greatest projection between the contiguous wrinkles (Jig. 264, 2.) A closer adhesion of Fig. 264. Similar villi as seen by transmitted light. The vilius marked 1, has been partially withdrawn by con- traction from its investing epithelium, which is thus left entire like the finger of a glove. a, epithelium of the vilius; b, granular matrix or substance of the same. those columnar cells which occupy the free extremity of the vilius, frequently causes this part to be defined, as a shallow funnel, by the neighbouring separated cells. While in other instances, a variable length of the whole vilius withdraws from its cellular investment with such uniformity, as to leave the extremity of the latter empty, smooth, and uninjured (fig. 264, 1.), like the finger of a glove. Frequently, how- ever, some of the epithelial cells are detached. It is obvious that all these appearances are referable to a contraction of the un- striped fibres within the vilius, withdrawing the substance of the latter from its epithelial in- vestment. The movements which often ac- company these changes resemble those above mentioned as beheld during life ; and consist of shortening or elongation, to which are some- times added lateral displacements. The date of their occurrence is limited to the period and the exposure, which are involved in such an opening into the intestine as is necessary to allow a proper inspection of the villi,— Gruby and Delafoud remark, that their surface becomes wrinkled and pale at the time of their contraction. Such circum- stances imply so much disturbance of these soft structures, as to throw great suspicion upon any view which would interpret them as part of a normal process. STOMACH AND INTESTINE. 355 which immediately succeeds death. And their duration is rarely protracted beyond a few minutes. Changes in the villi during digestion. — Dur- ing the act of digestion, the villi undergo cer- tain noticeable alterations. At this period, they receive an increased afflux of blood ; and become both larger and softer. They ac- quire a greater opacity ; so as to appear whiter by reflected, and darker by transmitted, light. The nuclei and cells which occupy their in- terior are greatly increased in number and dis- tinctness. And, finally, after the ingestion of food containing the usual fatty ingredients, a portion of these may be found occupying the interior of the villi themselves. The process by which fatty matter pene- trates the villus to enter the lacteal in its centre, deserves our special attention, from the fact that it constitutes the origin of the chyle. At present we shall limit ourselves to a description of the appearances actually observed, in connection with the mucous membrane of the alimentary canal. The first step towards the absorption of the fatty matter, consists in its entry into the epithelium which invests the exterior of the villus. Each columnar cell of this covering is gradually filled by a large oil globule ; which occupies the whole of its cavity, with the ex- ception of that small portion devoted to its nucleus. This change first implicates a few scattered epithelia ; and, by rendering them Fig. 265. VWus of the dog about two hours after feeding : show- ing the entry of fatty into scattered epithelia on its surface. Magnified about 400 diameters. a, a, outline of the villus formed by epithelia with their ordinary contents; b, b, epithelia rendered bright and refractile by their fatty contents. more refractile, often causes various parts of the surface of the villus to offer a curious con- trast of bright spots (b,fig. 265.) and darker intervals.* Gradually, however, all the cells become similarly affected ; so that the entire vilius assumes the altered appearance just alluded to. The next step towards the absorption of the fatty matter consists in the minute subdivi- sion of the single oil globule (c^Jig. 266.) which occupies the epithelial cell. The way in which this process occurs is unknown : Fig. 266. Isolated epithelial cells from a villus^ as seen during the absorption of fat into the lacteals. (Altered from KoeUiker.") Magnified 350 diameters. a, columnar epithelial cell, occupied by fatty molecules; b, similar cell, containing several small oil-drops; c, similar cell, enclosing a single oil- drop ; rf, similar cell completely filled by a larger oil -drop. The upper or free end of the cell (at d) js concave. but the result of the change is to give the columnar cell a darkly granular appearance (#, Jig 266.), in which we may often distin- guish separate, though minute, fatty mole- cules. These molecules are next found in the substance of the villus itself, though chiefly towards its surface and free extre- mity ; — to the apex of which latter part they are often limited.-f- From the sub- stance or matrix of the villus, the molecules of fat are then transferred to the lacteal trunk occupying its centre ; which, in the most fa- vourable instances, they define as a slender column of dark fatty granules. How far the above process constitutes a mere act of physical imbibition, it is difficult at present to determine. But that it is so, at least in part, can scarcely be doubted. For the experiments of Matteucci J (which are con- firmed in all their essential particulars by Valentin §) prove that, when a dilute alkaline solution and a faintly alkaline fatty emulsion are separated from each other by an animal membrane, diffusion occurs between them. And the circumstances actually present in the intestine are even more favourable to such a transit than those which obtained in the experiments of these observers. The lymph and blood are sometimes more alkaline than the solution which they made use of. The degree in which the tenuity of the delicate cell-wail of the villus exceeds that of the * These appearances, alluded to by Frerichs ( Op. cit. p. 854.) and detailed by Koelliker (Op. cit. p. 167.), were noticed by me eight years ago in the human subject. f The larger drops sometimes seen in this situation are, I believe, the result of accidental violence to the specimen. t Le9ons sur les Phenomenes, &c., pp. 104, 5. § Op. cit. vol. i. p. 379. A A 2 356 STOMACH AND INTESTINE. compound membrane forming the diffusive septum in their experiments, would propor- tionately favour the resulting transit of the separated fluids. And since the continuous movement of the chyle is probably aided by forces independent of any mere act of dif- fusion, the force of suction thus added must itself conditionate a more active transit than that which they witnessed in the inert en- dosmometer. On the other hand, there are good reasons for regarding the reception of fatty matters as a much more complex phenomenon, and the result of what we may venture to call more vital processes. For the way in which ether and other solvents act upon the chyle appears to prove, that the fatty contents of its molecules are still oily ; and not saponified, like such diffused fluids. And while the position of the capillary plexus, and the rapid- ity and quantity of its stream, render it pro- bable that any merely diffusive action would disproportionately affect the blood — -which by the way is often more alkaline than the chyle -^-a chemical and physical comparison of these two fluids would seem to show that the re- verse is actually the case : tbat a larger quan- tity of fat is taken up by the lacteals than by the blood-vessels. This view is also con- firmed by the results of violent inflamma- tion*, or of great interference with the blood- vessels j : — changes, neither of which would probably have much direct effect on the physical action of an independent system of tubes, but which are nevertheless alleged entirely to pre- vent the formation of chyle. In any case, it would seem that there are strict limits to the quantity of fatty matter which can be absorbed. Hence when the amount of fat present in any particular region at all exceeds what its villi can take up, it is passed on to other portions of intestine ; failing absorption by which, it is ultimately discharged unchanged in the faeces. Intestinal Follicles. ,J — We pass on to the description of a class of structures which are essentially closed sacs; and which, represented in the stomach by the lenticular glands, pervade all the remainder of the intestinal canal under the two forms of solitary and agminate fol- licles : the latter being, as their name implies, essentially clusters of the former. Agminate follicles. — Of the very numer- ous § names which have been bestowed upon * French s, Loc. cit. t Fenwick in " Lancet " for 1845, p. 64. | The etymology of the word "follicle " quite permits its application to these closed sacs : to which indeed it seems desirable that we should restrict it^ in speaking of the various constituents of the intes- tinal mucous membrane. § Until a more uniform nomenclature is adopted, it seems advisable to enumerate a few of these names. Such are the titles of glandulee Peyerianee ; agmina Peyeri ; glandulee aggregates ; glandules, agmi- nate ; vesicularum agmina ; plexus intestinaks ; plaques gaufrees; and finally, Peyer's patches. The latter uncouth designation is, perhaps, that most com- monly made use of in this country. But as Peyer appears to have been anticipated b}' our countryman Grew in the discovery of these structures, there is the less need of clinging to one of those unmeaning these follicles, that above made use of seems preferable ; since it best connotes both their structure and arrangement. There are generally about twenty clusters of these agminate follicles scattered throughout the small intestine. Their shape is commonly that of an oval, having a length about twice its width. They are situated on the free border of the bowel, or opposite to the attachment of its mesentery ; and usually correspond to about the lower three-fifths of the small intestine, or to that part of it which is regarded as the ileum. Hence they have been looked upon as, in a certain sense, characteristic of this region. But they some- times extend into the jejunum, being scattered sparingly throughout its lowest segments. And they may rarely be found even in the duodenum. In such cases, their entire number is usually about twice or thrice that of the average given above. But amid all their variations of number, size, and extent, the agminate follicles seem to retain a certain predominant relation to the end of the ileum. For it is here that they are both largest and most numerous. And while in the remainder of the small intestine, their length is usually rather under than over an inch, nothing is more common than to find the immediate neighbourhood of the ilio-caecal valve occupied by a single irregular cluster ; — which has a length of two, three, or even four inches, and a width which carries it round £ils or fths of the inner circumference of the intestinal tube. Fig. 267. Agminate follicles as seen by reflected light. Magni- fied 4 diameters. (After Kodliher.} _ a, general mucous surface with villi ; b, depres- sions leading to the several follicles; c, intervals between them, covered by small villi. On examining the mucous membrane of the surnames, which every practical teacher of anatomy will probably agree with the author in thinking very objectionable. STOMACH AND INTESTINE. bowel by reflected light, at a place corre- sponding to a cluster of agminate follicles, we see that its surface (which is raised above the rest of the intestine, but has no very sharp line of demarcation from it) is occu- pied by a number of irregular shallow de- pressions (6,j%. 267.), at tolerably uniform dis- tances from each other. But when inspected by transmitted light, these fossae are replaced Fig. 268. Agminate follicles as seen by transmitted light Mag- nified about 5 diameters. (After Boehm.) a, general mucous surface of the ileum ; bt b, opaque grains corresponding to the several follicles. by comparatively opaque grains (b^b,^g. 268.), of about the size of a millet seed ; the aggre- gation of which renders the whole cluster very distinctly visible by this mode of exami- nation. Finally, the cluster may often be recognised externally, from the bulging of the peritoneal coat which it causes in this situa- tion. Indeed, its constituent follicles may sometimes be seen glimmering through the delicate muscular tunic. Each such cluster is composed of a number of follicles, varying from twenty or thirty in the smaller, to at least one or two hundred in the larger, specimens. A careful examination of the mucous surface shows that the depressions just mentioned do not lead to any apertures, but are terminated by a smooth surface, the convexity of which somewhat diminishes their own depth. It is only at the margins, and in the intervals, of these fossae, that we find the tubes and villi proper to the small in- testine. And both of these latter structures are somewhat modified. Those tubes which immediately surround each depression have a circular or elliptical arrangement ; so that their orifices generally form a ring of ten to twenty tubes in the fossa (around a, Jig. 269.), and thus give rise to a 357 very characteristic appearance.* In like manner, the villi in their immediate neigh- bourhood often appear to radiate outwards Fig. 269. ; >^^ Portion of a cluster of agminate follicles. a, a, follicles encircled by apertures of the intes- tinal tubes in the form of a ring ; 6, short and ob- tuse villi, occupying the intervals of the follicles ; c, apertures of intestinal tubes, opening irregularly in these intervals. from a point corresponding to the centre of the fossa. And both they, and those more equidistant to the several follicles, are very different from the villi seen elsewhere : — being fewer (b,fig. 269; a, fig. 270.), shorter, of more irregular form, and often confluent at their bases. To demonstrate the structure and arrange- ment of the several constituent follicles of the agminate clusters, requires great care, and very delicate manipulation. At the free surface of the mucous membrane, they are extremely difficult to isolate ; both from their great tenuity, and their intimate union to the neighbouring tubes. Hence the best way of gaining access to them is from the outside of the intestine, where they may often be seen through the peritoneal and mus- cular coats.f The removal of these tunics brings them directly into view. To this method of examination must be added care- ful section in the vertical and horizontal planes. A proper combination of all these methods of investigation reveals the following facts.— Each follicle is a shut sac : having a round^h form, but a somewhat conical apex, which is directed towards the surface of the mucous membrane. Their diameter varies from 1 to 2 or 3-50ths of an inch. The base of each is in contact with the muscular coat (which is somewhat thinned in this situation) ; and is united to it by an areolar tissue that resembles the ordinary loose sub-mucous texture, in which the follicle is imbedded by the greater part of its bulk. The short apex of the follicle extends upwards between the lower extremities of the intestinal tubes : and, below their middle, it terminates in the immediate neighbourhood of the general mucous surface, which has already been * This appearance is somewhat incompatible with that seen in a vertical section. Hence it is perhaps partially due to pressure or over-distention of the follicle. t Especially after having been rendered opaque by soaking in dilute acids, which coagulate their contents. A A 3 358 described as depressed into a fossa in this situation. The thin stratum of tissue which 270. STOMACH AND INTESTINE. Plan of an agminate follicle, as seen by a vertical section. Magnified 40 diameters. a, short and conical villi surrounding the follicle ; b, intestinal tubes in the same situation ; c, muscu lar stratum of the mucous membrane ; d, submu- cous areolar tissue, in which the follicle is chiefly situated ; e, circular layer of the muscular coat ; /, longitudinal layer of the same ; g, peritoneal coat ; h, follicle enclosing nuclear contents ; z, apex of the follicle projecting into the cavity of the bowel. intervenes between the follicle and the interior of the bowel (at i,fig. 270.) is so delicate, that its exact anatomy is not easily verified by vertical sections. It appears, however, to con- sist of a very small quantity of indistinctly fibrous tissue ; which encloses some capillaries, and is covered by the ordinary layer of co- lumnar epithelium. The frequent rupture of the follicle in this situation has led many to regard it as either possessing a permanent orifice here, or ac- quiring one by a kind of natural dehiscence. But later researches seem to show that this open state is quite exceptional and accidental ; being due to disease, putrefaction, or mechanical violence. The author can at least express his own conviction that — as Boehm long ago stated, — the agminate follicles are closed sacs. This conclusion is much confirmed by the fact, that the follicles of some animals are altogether beneath the mucous membrane and the tubes, and quite distinct from both of them ; so as to lie wholly in the sub-mucous areolar tissue.* While the vascular arrange- ments which we are about to describe seem equally incompatible with any theory of their normal dehiscence. Each of these follicles essentially consists of a capsule, enclosing a number of delicate capillaries, the interstices of which are occu- pied by a cell-growth consisting of various forms. The capsule is a structure which, though analogous to a basement membrane, differs from such a delicate homogeneous lamina, both in being much thicker, and in offering an in- distinctly fibrous texture. Its smooth outer surface contains elastic fibres, and is attached by loose areolar tissue to the surrounding sub-mucous structures. The vessels of the follicle offer a very peculiar arrangement. The small arteries in the sub-mucous areolar tissue give off branches that ramify amongst the several follicles of each "patch;" and thus form a network of Fig. 271. Vessels of the three agminate follicles of the Rabbit ; as seen by a horizontal section, at about the middle of their height, (^fter Koelliker ; from an injection by Fret.') a, «, minute vessels surrounding the capsule of the agminate follicles ; b, b, b, delicate capillary loops „, penetrating their interior, and bending back from c, c, c, the centres of the follicles. capillary arteries, chiefly occupying the hori- contact with the capsule of the follicle, break zontal plane. These vessels, which are in * Compare Koelliker, Op. tit. pp. 153. 188. STOMACH AND INTESTINE. 359 up into numerous capillaries of about of an inch in diameter. The latter surround the membranous wall of the follicle with an irregular plexus. But where they reach the middle of that part of it which projects into the interior of the intestine, they are curved back upon themselves ; so as to form long loops, that radiate from a central space quite uncovered by vessels. And this appeal ance, which was depicted long ago by Boehm, does but represent, at the surface of the follicle, what the more recent researches of Frei prove to be the vascular arrangement that per- vades the whole of its interior. The injections of this anatomist show, that the capsule is not only surrounded by the network just men- tioned, but is also penetrated by a number of minute capillaries. These, which are of a still smaller diameter than the former ves- sels, leave them at right angles, and reach nearly to the centre of the follicle, before looping back again to its exterior. And finally, some of the uppermost of them have been traced by Koelliker uniting to form the radicle of one or two veins of about T^ootn of an inch in diameter; which descend verti- cally through the follicle, without receiving any further branches from the neighbouring capillaries. The remaining contents of the follicle form a soft pulpy mass. This is remarkably con- trasted with the contents of the neighbouring lacteals, in the fact that it is always of a pale, semi-transparent, greyish colour ; while the latter are, during digestion, of a brilliant white. The application of reagents under the microscope shows this greyish pulp to be composed of a proteinous substance closely akin to albumen. The addition of water causes it to swell up, and effects its partial solution. And as regards its structure, the mass consists of a moderate quantity of fluid, mingled with a variety of cells. These, however different in their characters, may probably be all reduced to various forms of cell-growth, on the one hand; and various stages of the retrograde solution of blood-cor- puscles, on the other. The latter process, though by no means uncommon, appears always due to an extravasation of a more or less accidental character. It is the cell- growth which constitutes the specific histo- logical character of these albuminous contents of the follicle. The cell-growth ranges from distinctly nu- cleated cells, of^J^oth of an inch in diameter, to cells of about one-half, and through these to nuclei of barely one-third, the above size. The latter, however, are of nearly the same bulk as those contained in the largest cells. Hence it would seem that the process of growth which these differences indicate, consists chiefly in the isolation and removal of the cell-watt, from its previously close apposition around the nucleus. In the Sheep, however, Koelliker has sometimes observed an endogenous multiplication of large cells, by a subdivision of their nuclei. And in other specimens from the same animal, he has noticed what is very possibly the opposite extreme of the cell-life : — the cavity of a large cell filled with large angular corpuscles. These corpuscles are sometimes nucleated; they have albuminous reactions; and they appear to be produced from the ordinary cells of the pulp. They ultimately disappear. The function of the agminate follicles it is impossible to specify. Few organs in the body have been the subject of more numerous speculations: — speculations, the absurdity of most of which renders them unworthy of any serious mention. And hence, although what we know respecting the structure of these organs justifies (or rather requires) some attempt to indicate their physiological import, the mistakes of others may well teach us how much caution is requisite in making such conjectures. They are, at most, mere guesses at truth. The contents of the follicle have just been stated to be composed of a cell-growth that lies in contact with a large vascular surface. Hence it is in the reaction of these innu- merable minute agents on a copious and rich nutritional fluid exsuded from the blood, that we must look for the chief office of the follicle. The fact of various stages of cell-life being present simultaneously, appears to in- dicate, that the cells do not merely select certain materials, but more or less produce them ; by a process which, directly or indi- rectly — by absolutely consuming their tissue, or otherwise — involves their own decay and death. So far, then, the agminate follicle, which closely resembles the vascular gland in its structure, might be conjectured akin to it in its function ; — that function being a choice from the nutritional fluid of certain of its con- stituents, which, after undergoing a metamor- phosis, are subsequently returned into the general current of the blood. But such a view omits to recognize some of the circumstances it ought to explain. And it especially neglects one which must be sup- posed of great importance : namely, the situa- tion of the follicle ; or, in other words, its peculiar relation to the cavity of the intestine. It is obvious that the position of the agmi- nate follicle with respect to the intestinal canal will admit of a double interpretation. On the one hand, the materials on which its enclosed cells have to act, will probably be derived from the contents of the alimentary canal, as well as from the blood. And on the other hand, they may be ultimately excreted from the body through the intestine, as well as re- turned into that system of closed canals which the blood vessels compose. The degree in which the intestine forms the channel of such an ingress and egress, must of course depend upon the directness and effi- ciency of the communication between its ca- vity and that of the follicle. Hence, where the two are in such close contiguity to each other as in the case of the agminate glands of the human subject, we may presume that an efficient transudation of this two- fold nature really does obtain. But where, A A 4 360 STOMACH AND INTESTINE. as in some of the follicles of the Calf, the cavity of the intestine is separated from that of these minute sacs by the inter- vention of a thick compound mucous mem- brane, it is difficult to avoid the conclusion ; that a transit of their fluid contents, in either, direction can only obtain to a compa- ratively small amount. In addition to these important relations between the agminate follicle on the one hand, and the vascular and intestinal cavi- ties on the other, recent observations have shown that there is a third, which is perhaps quite as intimately connected with its func- tion : — namely, the connection of the follicle with the commencement of the lacteal system. For the general analogy of the intestinal follicle to the vascular gland is far surpassed by that close structural resemblance which Koelliker has shown that it possesses to the follicles of the lymphatic glands. The latter, indeed, exhibit a remarkable similarity to the structure of the agminate follicles. Like them, they enclose vessels as well as cells, within the cavity formed by their limitary wall. Hitherto it has certainly been found impossible to verify the presence of lacteals within the agminate follicles; or to establish the existence of any direct communication between their cavities and that of the lacteal vessels them- selves. But in spite of this, it seems certain, both that the lacteals occupy the patches in numbers quite disproportionate to the small and few villi here present ; and that they possess the closest proximity with the contents of the follicles. Such a * conclusion must, I think, be drawn from Bruecke's researches ; in which the cavity of the follicle soon became slightly coloured with reddened turpentine, which had been injected into the lacteals by compressing the distended intestine. It remains, however, for future researches to determine how far this view is correct, and whether the agminate follicles do really par- take of the nature and office of lymphatic glands. In any case, their very variable number, and their occasional absence, would seem to indicate, that (like the similar struc- tures always present in the tonsils, and some- times found in large numbers within the mucous membrane of the stomach) their function is either not very important; or — what is far more likely — can be more or less replaced by that of other kindred organs. And from the number and size of these follicles, we may perhaps conjecture, that their merely quanti- tative effect on the chemistry of the organism is not very great. The little that is known of their changes in health and disease confirms what has just been stated respecting their relations to the * That direct communication between the agmi- nate follicles and the lacteals, -which Bruecke de- duced from his observations, is, however, contradicted by the time at which the colour above mentioned appeared, and by its diminished intensity of hue : — as well as by the fact, that the agminate follicle never contains white chyle. vascular and lymphatic systems. Thus, dur- ing digestion, they become so swollen, as to project from the inner surface of the intes- tine : — a condition that may, perhaps, be due to increased absorption from the intestine, but is better ascribed to that energetic determina- tion of blood to the whole of the intestinal structures which then takes place. During the violent drain of cholera the same tumid condition obtains : probably from a similar cause. And finally, the remarkable parallel between the disease of these follicles and that of the neighbouring mesenteric glands, which is seen both in phthisis and typhoid fever, is a strong additional argument for the reality of that analogy which physiology indi- cates to exist between the two structures. Solitary follicles. — The solitary follicles are so completely what their name implies — isolated structures of the same kind as those which are aggregated to form the "patch" — that any further description of their mi- nute anatomy would be quite superfluous. Indeed, those smaller patches which are formed by two or three follicles, may be almost regarded as a transition between the "solitary" and" agminate" arrangement. But these scattered solitary follicles are seldom or never surrounded by a definite circle of the apertures of intestinal tubes. And they often sustain villi of the usual size and shape. Their number is extremely variable. Some- times they seem to be altogether absent. But a very careful examination will now and then show, that such a deficiency is one in appear- ance only ; and is due to the very slight degree of distention which obtains in the follicles really present. Whether this explanation would always hold good is more doubtful: though the remarkable constancy with which these structures are found in most animals and in the human foetus is, to say the least, a strong confirmation of its general truth. In other instances they are strewn thickly over the whole intestinal canal, from the oesophagus to the anus. Such an excessive development is perhaps strictly a morbid phenomenon. But it is also capable of ex- planation as a mere collective hypertrophy ; — an overgrowth which results in an increased number of these minute organs, instead of an increased size of each individual follicle. Which of these two views is the more correct, will only be decided when we know more respecting their office. They usually occupy the whole of the small and large intestine in considerable numbers. They are, however, more numerous in the latter of these two segments of the diges- tive tube. And here they also present a larger size, as well as what is generally a deeper situation in the sub-mucous areolar tissue. Hence the depression that indi- cates the follicle in the small intestine is exaggerated, in the large intestine, into a deep fossa ; which, commencing by an aperture over each follicle, widens as it passes downwards between the opposed sides of a few contigu- ous intestinal tubes, to terminate, near their STOMACH AND INTESTINE. 361 extremities, on the bulging surface of the fol- licle. Racemose, or Brumfs glands. — The re- maining constituent of the compound intes- tinal membrane is one which, unlike all the preceding minute organs, is limited to a very small segment of the canal. It consists of a number of highly ramified tubes, which are usually termed the glands of Bnmn, but might preferably be named the racemose or duodenal glands. These glands occupy that upper part of the small intestine already distinguished as the duodenum ; of which segment they are thus, as it were, the natural index, or the characteristic structure. The racemose glands are small " conglo- bate " masses ; which in their size, structure, and position, closely resemble those accessory salivary organs that stud various parts of the mucous membrane lining the cavity of the mouth. Like these " labial" and "buccal" glands, they occupy the sub-mucous areolar tissue : and are therefore best examined by pinning out a piece of the duodenum on some flat surface, with its mucous side downwards, and then carefully removing the serous and muscular coats. Such a dissection easily ex- poses them, as small roundish white granules of about the size of a millet seed. They vary considerably in size and arrange- ment. Immediately beyond the pylorus, they are of one-tenth to one-eighth of an inch in diameter ; and are present in such num- bers, as to form what is almost a glandular layer around this part of the intestine. But lower down in the duodenum, their size dwindles to one-half or one-third of the above : and their scattered grains gradually become more sparing in number; until, shortly before the termination of its inferior transverse portion, they cease altogether. On tracing out the structure of an isolated duodenal gland under the microscope, it is seen to consist of numerous lobules; which are aggregated into a single mass (c c,fig. 272.), by an enveloping layer of fibrous tissue. And on applying a still higher magnifying power, each of these lobules may be again resolved into smaller ones, which resemble a bunch of grapes, and constitute the true or ultimate acini of the gland. As seen in situ, these vesicles have a globular or slightly polyhedral form; and a diameter which is about -s^th to ^^th (on an average, m^th) of an inch. But when separated from each other, they often exhibit more irregular shapes (d,fig. 273.). They are the terminal dilatations of tubes, which are themselves about two-thirds of this size. On tracing these minute tubes towards the general mucous surface, they will be found uniting with other similar ones, to form larger ducts. The successive union of these with other ducts formed in the same way, and of these larger ducts with their neighbours, gradually causes all their cavities to converge into a single canal of outlet, which is the proper efferent duct of the gland. This duct now passes between the intestinal tubes before described, to open on the free surface of the intestine, in the depres- sions which intervene between the rudimen- tary villi present here. The valvulae conni- Fi%. 272. Racemose or duodenal gland, as seen in a vertical section of the duodenum. Magnified 40 diameters. a, intestinal tubes ; b, muscular stratum of the mucous membrane ; c, c, acini of the duodenal gland, which occupies the submucous areolar tissue ; d, transverse layer of the muscular coat ; e, longitudi- nal layer of the muscular coat ; /, peritoneal tunic of the bowel. ventes are not permeated by any such ducts. But in all other parts of its surface, the general mucous membrane is pretty evenly Fig. 273. Diagram of the arangement of the lobules of a duode- nal gland. a, duct of the lobule ; b, collateral branch of this duct ; c, the acini around such a duct in situ ; d, the same separated, and the duct unfolded. studded by their apertures, two or more some- times'passing through it in company with each other. Hence each of these glands may be briefly described as a tube, which branches'repeatedly, and ends in very minute canals, with some- what vesicular extremities. The whole of this involution of mucous membrane is composed of the usual elements j namely, limitary membrane and epithelium. The former constituent offers no peculiarity worthy of note. The latter consists of a single tesselated layer of cells. These have a poly- gonal and slightly flattened shape, which some- 362 STOMACH AND INTESTINE. what resembles that of the cells lining the smaller branches of the straight urinary tubules. Where the smaller tubes converge to form the efferent duct that perforates the mucous membrane, these cells are exchanged for short cylinders, the structure of which rapidly merges into that of the ordinary columnar epithelium of the general intestinal surface. As regards the secretion of these racemose glands, we can only state that their ducts contain a structureless mucus, which has an alkaline reaction. With such an imperfect knowledge of its na- ture, we can scarcely wonder that the office of this fluid remains unknown to us. Like many other animal matters, it converts starch into sugar. But until the precise rapidity and energy of this change have been established, it is im- possible to determine how far this action is really comparable to that of the saliva. From the close resemblance between the sub-mu- cous glands of the mouth and these of the duo- denum, many have assumed them to prepare a salivary fluid. But, besides that we are not warranted in regarding the secretion of the buccal glands as identical with the saliva (of which it forms but a very small ingredient), a very moderate knowledge of histology might suffice to indicate the danger of inferring the nature of any secretion from the mere arrangement of the structures by which it is furnished. Hence it must remain for the present undecided, whether this mucus is a salivary or pancreatic fluid ; or merely a more concentrated form of intestinal juice, secreted by glands which here reach a higher degree of development than that attained by the short cylindrical tubes of the rest of the bowel. Large intestine. — The remaining portion of the alimentary canal forms the large intestine Fig. 274. Large intestine, as seen in situ, in a state of moderate inflation. The anterior wall of the belly, and the small intestine, are supposed to have been removed. c, caecum ; a, ascending portion of the colon ; t, transverse portion ; d, descending portion ; s, sig- moid flexure ; r, rectum. (c a t d s r^fig. 276.) (intestinum crassum, Lat. ; gros intestm, Fr.; dickes Gedarm, Germ.): — a name which alludes to the size that is one of its chief characteristics. Beginning at the termi- nation of the ileum, in the right iliac fossa, it passes upwards to the under surface of the liver. Here it turns at a right angle, and runs horizontally below the stomach, to the left extremity of this organ. By a second bend, it here resumes the vertical direction, and then passes downwards towards the left iliac fossa. In this region it undergoes a remark- able curvature, which has the shape of the italic letter S. From the lower end of this "sigmoid" flexure, it passes obliquely towards the median line ; where it terminates in a straight, short tube, that runs vertically through the pelvis to the outlet of the anus. Hence the entire segment of large intestine has the shape of a horse-shoe; and forms a large bend, which is concave downwards, and passes almost round the confines of the abdomen before ending at the inferior extremity of this cavity. While its general arrangement is such, that the intestinal canal, which diverges from the median line at the lower end of the oesophagus, returns to it shortly before terminating in the posterior or lower segment of the trunk. An accurate measurement of the length and width of this tube is opposed by the diffi- culties already alluded to in the case of the small intestine. My own observations would indicate an average length of from four to six feet, and a mean diameter of about If to 2^ inches: — the two measurements usually vary- ing inversely to each other, except in the cases of extreme distention or contraction, when both respectively increase or decrease simul- taneously. Hence the large intestine has about a quarter the length, and twice the width, of the small. From such an estimate we may conclude that, while its capacity is almost equal to that of the narrower tube, its active surface is scarcely half as large. And even this great difference is much in- creased by the absence of villi and valvuloe conniventes from the interior of the large in- testine. Like the rest of the canal, the wall of the large intestine is composed of the serous, mus- cular, and mucous coats; and of vessels, nerves, and lymphatics, which are distributed to them. The nature and arrangement of these tunics vary, however, in the several parts of the tube. And these differences, aided by others which affect its size, shape, and situa- tion, subdivide the large intestine into the following segments : — the ccecum ; the vermi- form appendix; the colon, in which we dis- tinguish an ascending, transverse, and descend- ing portion, and a sigmoid flexure ; and, finally, the rectum. The anatomy of each of these will demand a brief notice. The ccecum (c,Jigs. 276, 277.) (formerly blind gut, Eng.; blind Darm, Germ.) is the first and largest of these segments. Its arrangement may be described as due to the fact, that the small intestine, instead of being simply continuous STOMACH AND INTESTINE. 363 with the large (like the stomach with the duo- denum), opens into it at right angles to its axis, and at some distance from its commencement; so as to leave a blind extremity of the larger tube at the site of their mutual junction. The size of this cnl-dc-sac generally exceeds that of the remainder of the bowel ; it being larger than any other part of the alimentary canal, with the single exception of the stomach. When moderately distended, its diameter ranges from 2£ to 3£ inches ; and its length is about as much. Its vertical extent is, however, somewhat arbitrary ; since, though defined in part of its circumference by the aperture of the ileum and by the ilio-caecal valve, it is elsewhere only limited by an imaginary line drawn around the tube at the level of the latter orifice. The situation of the caecum, in the left iliac fossa, allows it to vary considerably in size, without undergoing any marked change of its relations. Bound down as it is to the fascia over the iliacus muscle by peritoneum and loose areolar tissue, its enlargement merely causes it to displace such portions of the small intestine as may hitherto have shared the oc- cupation of the iliac fossa. After its distention has removed these from its anterior surface, it reaches the anterior wall of the belly in the iliac region ; where its size, shape, and con- tents can be more or less recognized during life, by the ordinary means of physical investi- gation. The above dimensions render it obvious that the shape of the caecum is somewhat globular. This shape is, however, modified by the arrangement of its muscular layers; which here begin to offer a peculiarity that is main- tained throughout the whole of the colon. The uniform external or longitudinal layer present in the small intestine is here contrasted by one which is separated into three flattened bands, that occupy the side of the tube at nearly equal distances from each other. In the caecum one of these (and the larger of the three) is ante- rior ; one posterior ; and one external. And all three of them become continuous above with the corresponding bands around the as- cending colon. Between these slips of muscle, the bowel presents a more or less dilated and projecting external surface ; which is again sub- divided by transverse constrictions into subor- dinate pouches or sacculi. On laying open the bowel, and removing the mucous membrane from its inner surface, it may be seen that these transverse constrictions are in reality formed by the circular muscular coat ; which gives off projections or incomplete septa, that compli- cate the general cavity of the tube, by adding a number of supplementary cells. These cells are arranged in three vertical rows ; which are separated by ridges, that correspond to the external depressions formed by the longitu- dinal bands above mentioned. Between these bands, the " haustra" or pouches of the bowel possess a muscular tunic of very inconsider- able thickness : the transverse or circular layer being reduced to a thin membranous lamina ; and the longitudinal being, as before stated, altogether absent. The close relation of these longitudinal and transverse septa to the length and width of the bowel is well shown by the effect of cutting across or re- moving its three bands, and then distending the tube by artificial inflation. This obliterates the " falciform folds " or transverse septa ; and thus converts the sacculated intestine into a canal, the length and diameter of which are nearly double of what it formerly pos- sessed when retained in its proper shape by its longitudinal bands or " taeniae." The serous covering of the ccecum is chiefly remarkable from the closeness with which it generally attaches the bowel to the fascia over the iliacus muscle. When the tube is but moderately distended, it covers only its ante- rior surface. Extreme contraction can, how- ever, render it a more complete covering; and may even produce it into a kind of meso- caecum behind the bowel. While conversely, great distention of the tube reduces the peri- toneum to a partial investment ; which occu- pies but a third, or even less, of the intestinal surface. The mucous membrane of the coecum differs in no essential respect from that of the re- mainder of the large intestine, the structure of which is continued up to the very edge of the valve which severs it from the ileum. The caecum has three apertures: — one, a large opening by which its cavity is directly continuous with the colon ; a second, which communicates with the small intestine, and is guarded by a double valve ; and a third, which opens into the slender vermiform appendix. lleo-ccBcal valve. — The opening into the ileum is situated at the upper border of the coecum ; on its left side, and a little poste- riorly. The structures which bound and define this opening are collectively termed the ileo- ccecal or the ileo-colic valve : — although these names ought in strictness to be limited to those separate portions of the entire intestinal valve which their etymology would indicate. The arrangement of the intestinal tunics in this valve is best seen by inflating and dry- ing that part of the intestine, which includes, together with the last inch or two of ileum, the caecum, and the commencement of the colon. On cutting out a piece of such a dried prepara- tion, so as to gam a view of its interior, we see the valve as represented in the accom- panying figure (Jig. 275.) The small in- testine, generally inclining slightly upwards as well as backwards, passes towards the caecum, at what is thus a rather acute angle. In- stead, however, of opening into the bottom of one of the sacculi of the caecum, it selects for its entry the exact site of the deepest and most projecting of those transverse constric- tions which project into the cavity of the large intestine. This constriction occupies the inner side of the bowel ; and is, as it were, split up by the entering ileum into two laminae ; — an upper and a lower, an ileo-colic and an ileo-caecal (e,f,fig. 275.) While, at the same time, the hitherto cylindrical calibre of the small intestine is gradually reduced to a hori- 364 STOMACH AND INTESTINE. zontal slit or fissure, as it enters this fold. Fig. 275. Caecum inflated, dried, and opened, to exhibit the arrangement of its valve. a, termination of the ileum ; b, ascending colon ; c, caecum ; d, transverse constriction projecting into the caecum from its inner surface; ef, valve sepa- rating the small from the large intestine ; e, its ho- rizontal ileo-colic lamina ; f, its more oblique ileo- czecal lamina; g, the vermiform appendix of the caecum. Such a description at once explains the form of the valve: — how each of its seg- ments, for example, constitutes a crescentic membrane, the plane of which meets that of its fellow at an acute angle, and the free edge of which is directed outwards ; — and how both end anteriorly and posteriorly in a commissure or fold, that gradually decreases in depth as it passes either forwards or back- wards round the intestine. As regards the details of its construction, each segment of the valve is chiefly formed by the prolongation of a corresponding por- tion of the circular muscular fibres of the ileum, together with a few proper to the large intestine. The assistance afforded to these by the attachment of the peritoneum and the longitudinal fibres of the ileum, to the fixed margin of each segment, is well shown by the effect of dividing the latter structures. For after such an injury, mode- rate traction draws out the valve into a sur- face, which is directly continuous with the lower end of the small intestine ; and at the same time converts its horizontal slit into a large elliptical aperture. The difference be- tween the ileo-cascal and ileo-colic portions consists chiefly in the fact, that the plane of the former is more oblique, and its margin more concave, than that of the latter. The mechanism of this valve may be easily deduced from its structure. In all states short of actual distention, the passive contraction of its muscular walls no doubt insures their contact, and shuts off the cavity of the ileum from that of the caecum. While any approach towards a more active dilatation of the large intestine — whether of the caecum, or colon — at once brings about a close apposition of the two portions of the valve. And what- ever aid may be given to this mutual apposi- tion of the surfaces of the valve bv its own active muscular contraction during life, no- thing is more certain than that its closure is essentially independent of any such vital pro- cess. For the gradual and equable distention of the caecum with liquid in the dead subject can also produce this result. Nor is it difficult to understand how such a closure is effected. The passage of the con- tents of the large intestine, over either plane of the valve, presses it against the opposite one, so as at once to close its orifice. Be- sides this, the free margins of the valve form segments of a larger circle than its attached ones. Hence they are disproportionately tightened by the same distending force. In this way, the double curve of each lamina is soon reduced to a straight line, that brings it into exact apposition with its antagonist. So that, within all ordinary limits, the greater the dilating force, the more closely are the two lips of the valve applied to each other. The only valid exceptions to this rule may be found in those cases in which the ileum and caecum are filled simultaneously. Such a process of distention necessarily occurs in all cases of mechanical obstruction of the diges- tive canal below this valve; as a result of the downward flow of the contents of the small intestines. And since it obviously distends the aperture by the application of a counter- force from the side of the ileum, its mecha- nical action is so simple as to require no further explanation. Its effect may indeed be seen in the caecum, as usually inflated and dried.* The function of this valve therefore offers a complete contrast to that by which the stomach opens into the small intestine. For while it affords little or no obstacle to an onward transit of the contents of the canal, it resolutely bars the way to all regurgitation: — an action which we have already seen is exactly reversed by the pylorus. And even in the absence of information respecting the details of its active contraction, its structure entitles us to conjecture, that the greater part of its efficiency depends upon a passive, and therefore permanent mechanism ; and not, as is the case with the pylorus, on an in- termittent (and vital) shortening of its mus- cular fibres. The use of the caecum is evidently that of forming a receptacle, in which the contents of the small intestine may sojourn for a certain time, before passing onwards into the colon. * Hence it is scarcely a superfluous caution to add, that in examining such a preparation we ought always to recollect, that the patulous orifice thus seen is in reality an abnormal one, which does not illustrate the mechanism of the valve in the healthy living body. STOMACH AND INTESTINE. 365 For not only are its shape, size, and direc- tion such as admirably adapt it to this pur- pose, but its development in different species and individuals closely corresponds to the degree in which such a delay is advantageous to digestion. Thus the large caecum of the Herbivora is contrasted, in the Carnivora, by one of but inconsiderable size and development. While there are grounds for conjecturing, that the habitual use of a vegetable diet is capable of increasing its size in the human subject. In all of these respects, however, its develop- ment does but parallel that of the remainder of the large intestine. We may therefore defer considering the nature of its secretion, and the changes undergone by its contents, until these segments of the bowel have also been noticed. The vermiform appendix (g,j%. 275.) which is so named from its resemblance in shape and size to a worm, is a small, smooth, cylindrical tube ; that opens into the caecum below (and rather posterior to) the aperture of the small intestine. Its length varies from one to four or five inches : its diameter from about a fourth to a third of an inch. Its attached end of course shares the situation of the contiguous part of the caecum. Its distal extremity is usually free ; and may hence be found in almost any situation which its length, and that of the short mesentery that binds it down, together allow it to take. Its opening into the caecum is often partially occluded by a kind of trans- verse fold or valve. As regards its structure, the vermiform ap- pendix exhibits all three of the ordinary coats. Its peritoneum is derived from that of the caecum, and often forms a short fold or me- sentery which is prolonged up a part of its length. Its muscular stratum is of uniform and considerable thickness, and is continuous with the three longitudinal bands which give the ceecum its sacculated shape. Its mucous membrane is occupied by tubes and follicles, like those of the colon. And the latter structures are often present in such extra- ordinary numbers, as to constitute almost a continuous layer of these minute closed sacs. The calibre of the tube, which is in general disproportionately small, is occupied by a sparing quantity of glairy mucus ; and occasionally, by small fragments of the ordi- nary intestinal contents. The use of the vermiform appendix is un- known. It has been suggested to be a mere relic of the umbilical duct of the foetus : — an erroneous view, to which allusion will hereafter be made in speaking of the development of the intestinal canal. It is almost peculiar to Man ; in whom its situation often causes it to receive small solids in their transit through the caecum, with the result of their becoming impacted in its narrow cavity. This accident is some- times followed by inflammation and perfora- tion of the tube, causing fatal peritonitis. The colon* (formerly Great gut, Eng.; * This Greek word, which has been adopted into most of the modern languages, is derived indiffe- Grimmdarm, Germ.), which forms by far the greater part of the large intestine, extends from the ilio-caecal valve to the rectum. Starting from the right iliac fossa, it passes vertically {a, Jig. 274.) up the posterior wall of the belly, and on the right side of the spine, until it reaches the under surface of the liver. A sudden turn at a right angle marks the end of this ascending portion, and the beginning of its transverse part. The latter segment, though tolerably horizontal, forms an arch (t,fig. 274.) with the convexity forwards, so as to pass around the projecting spine and aorta. Below the spleen it merges, by another rectan- gular bend, into the descending colon (d,jig. 274.) This takes much the same course on the left side of the abdomen as the ascending colon does on the right ; and opposite to the crest of the ileum, it ends by becoming continuous with the sigmoid flexure (s,fig. 274.), The latter portion is attached by a short mesen- tery to the left iliac fossa; and it terminates in the rectum, at a point corresponding to the left sacro-iliac symphysis. The relations of each of these segments to the adjacent textures and organs may be easily deduced from their course as described above. Thus the ascending colon lies on the right kidney and quadratus lumborum muscle, from which it is only separated by loose areolar tissue. On its left side, is the psoas muscle ; and above it, the vertical portion of the duo- denum. In front, it is covered by coils of in- testine ; or, if sufficiently distended to thrust these away, by the anterior wall of the belly. The transverse colon is almost always in contact with the omentum and abdominal pa- rietes, which it touches in the horizontal line that marks the mutual limit of the umbilical and epigastric regions. Above it, is the first portion of the duodenum; with the stomach, liver, gall bladder, and spleen. Below it, are the coils of the small intestine. Behind it, lie the second and third portions of the duo- denum, — the latter covering the aorta. To its posterior surface is attached the transverse mcso-colon; which connects this part of the in- testine with the wall of the belly, by a double fold of peritoneum, that splits to enclose the tube. The double lamina formed by the re- union of these two layers of serous membrane in front of the bowel, is continuous, at the lower border of the great omentum, with the similar process that descends from the great curvature of the stomach.* The descending colon, like the ascending, lies on the left kidney and the left quadratus lumborum muscle, and is covered by a va- riable quantity of the small intestine. The sigmoid flexure is much more frequently in contact with the abdominal wall than the preceding portion of the colon. And its freedom of movement, to which this contact is partly due, also allows the bowel to deviate considerably from its ordinary curvature and rent! y from *«*«», membrum, and *«*«*, atvus (T«$« TV* See Art. PERITONEUM. 366 STOMACH AND INTESTINE. position. The shape of this bend corresponds so exactly to its name, that it is scarcely necessary to bestow any further description upon it. Its curve is chiefly in the vertical plane ; though a slight lateral curvature is almost always present, and is easily exag- gerated into a much more distinct bend by the mobility of this segment of the canal. The use of the sigmoid flexure seems to be that of forming a receptacle for the faeces : — a receptacle of which the shape and arrange- ment are such as to spare the rectum and its sphincter from much of the pressure and weight against which they would otherwise constantly have to contend. When full, the convexity of its lower bend often projects below the iliac fossa, so as to descend into the pelvis. Indeed, the whole of the colon is very liable to displacement from the various po- sitions just assigned to it: — prolonged dis- tention by its accumulated contents, or the mechanical force exerted by the pressure of stays externally, or of tumours internally — being all capable of altering its relations, and even confusing its different parts* with each other. The colon retains the sacculated shape as- sumed by the cascum. Its size undergoes a progressive though slight decrease, from its commencement in the caecum to its termina- tion in the rectum. Its peritoneal coverings reach their minimum in the ascending and descending portions ; where they only cover about two-thirds of the moderately distended bowel, and leave its posterior or attached third quite unoccupied by this membrane, and con- nected by loose areolar tissue to the subjacent parts. Hence it is these portions of the bowel which are selected in the operation for artificial anus, -f- But, just as great distention can always increase this uncovered portion, so, vice versa, excessive contraction may reduce it to a mere line, or may even develope a kind of short meso-colon in connection with either of these parts. The muscular strata which cause its sacculated shape, also retain the arrangement existing in the coecum. But on the transverse colon, the internal longitudinal band becomes inferior. And on the sigmoid flexure, this and the posterior band generally merge into a single one. The latter change is accompanied by an indistinctness of the transverse sacculi themselves. Throughout the whole of the large intestine, the peritoneum is here and there developed into peculiar, processes, called the appendices cplploiccB (t?ri rXoov, omentum). These are short pouches of the serous membrane, which generally form flattened duplicatures or folds. They are prolonged from the peritoneum cover- ing the surface of the intestine itself; and are therefore absent from that portion of the rectum, or terminal segment of the large in- testine, which does not receive any covering * See Abnormal Anatomy. f Other things being equal, the left or descend- ing portion is preferred : on account of a larger extent of the canal being thus left to be traversed by the intestinal contents. of this membrane. Their number, size, and arrangement, are liable to great variety. Some- times they are so numerous, as to form a single or double row along the free surface of the bowel. In other instances they are very few and imperfect. Their size is so far related to the state of the bowel, that, like most other processes of peritoneum, they are enlarged by its contraction, and dimi- nished by its distention. From their con- tents, which consist of areolar and adipose tissue, they would seem to be small reser- voirs of fatty matter. Hence in cases of re- markable obesity, their size is much increased. Indeed they sometimes acquire a length of one or two inches ; and have even been known to encircle and strangulate the bowel. Movement of the large intestine. — The exact nature of the movement which is executed by the muscular coat of the large intestine can at most only be conjectured from some of its attendant circumstances. Like that of the preceding segment of the canal, though its general mechanism is obvious, its details remain unknown. As regards the investigation of the con- tents of this intestine in its ordinary situation during life, all that can be stated is, that, even in health, they include a quantity of gaseous matter ; which usually maps out the ccecum, and more or less of the colon, with tolerable distinctness, from the less resonant convolutions of the small intestine. After death, the quality and quantity of these contents are so much affected by the nature of the previous food, the mode of dying, and a va- riety of kindred causes, that scarcely any gene- ral proposition can be laid down with respect to them. But on the whole, we usually find, that in addition to much gaseous fluid, the cascum of the healthy subject is partially distended by pultaceous or semi-fluid contents. While the colon is occupied at various points of its length by matter, the faecal character of which is still more distinct, and the consistence of which gradually increases as it approaches the rectum. W here these rudimentary faeces are very im- perfect, scanty, and interrupted, they only oc- cupy some of the sacculi or cells of the bowel, leaving its central or general calibre in an empty state. But when better developed, they form what is termed a " figured " mass. This con- sists of a kind of central rod, that corresponds to the general axis of the tube; and of processes that come off from the sides of this axial por- tion, and are contained in the rows of pouches formed by the wall of the bowel. In short, the solid and continuous faecal substance forms a tolerably perfect cast of the bowel ; — a cast in which the sacculi of the colon are "figured " as projections, themselves isolated by depres- sions corresponding to the intersections of its longitudinal and transverse bands. The characteristic shape thus possessed by the solid contents of the colon, is often retained by the faeces which have been forced through the rectum in the natural process of defaeca- tion. And although it is often absent, — the con- STOMACH AND INTESTINE. 367 sistence of the faeces being such* as to mould them to the cylindrical form of the last-named portion of tube through which they have to pass — still it occurs so frequently in Man, and so universally in many of those Herbivora in whom we can best study the phenomena of a highly developed large intestine, as to afford a valuable testimony to the natural action of this part. It is therefore difficult to avoid believing, that the individual sacculi of the colon, or at least of its later segments, retain the faeces for a considerable period of time ; during which they so far complete the action of the large intestine upon these its contents, as to leave nothing for its remaining segments to effect, save their mechanical propulsion to- wards the outlet of the canal. To this inter- mittent action of the muscular coat in respect of time, we may probably add a similar inter- ruption as regards space. In other words, the interrupted and irregular manner in which the sacculi are often occupied by solid faeces, entitles us to suspect, that different lengths of the intestine can act independently of each other. But it is difficult to hazard a con- jecture as to whether the contraction of the falciform transverse folds ever really shuts off portions of the tube into distinct cavities. The central axis of the figured evacuation is, however, often so slender, or even interrupted, as remarkably to corroborate such a view. And some authors have assumed that the caecum, during its digestive act, is isolated from the ascending colon by a vigorous con- traction of that large fold which is prolonged from the frrena (or anterior and posterior extremities) of the ilio-caecal valve.f The little information afforded us by direct observation on the movements of the intestine, confirms what is thus vaguely suggested by the appearances of its expelled contents. The highly developed large intestine of the living or newly-killed rabbit, rarely exhibits any noticeable movement whatever, when first ex- posed to the air. By and bye, however, a kind of irregular peristalsis comes on. But this is nowhere quite so energetic as that seen under similar circumstances in the small intestine ; * The consistence of even a figured evacuation is sometimes so slight, as to render it highly probable, that a general relaxation of that segment of in- testine which originally contained the faecal mass has accompanied the propulsive contraction of the part immediately behind it. Such an apparently co-ordinate relaxation of the muscular coat may be frequently noticed in that vermicular movement of the small intestine which is seen shortly after death. An occurrence of this kind seems almost the only way in which one can account for the fact, that soft and semifluid faeces frequently retain the form of the colon, after passing 'through its falciform folds. Whether sucli an action is ever effected by a contraction of the longitudinal bands simultaneously with a relaxation of the circular or falciform folds, it is impossible to determine. But from their mechanism, and from the above appear- ances of the faeces, it would seem more probable that both these classes of fibres relax simultaneously. f Energetic contraction of the transverse fibres of this valve would obviously aid in its occlusion ; though we have already shown it to be probably independent of all active muscular force. and is generally very feeble in the caecum.* And in this movement, as in that produced by mere local irritation, we may notice the peculiar character before attributed to the contraction of unstriped muscle generally ; — viz., that of diffusing itself over a time and space greater than those occupied by the irritation which has excited it. As regards the details of this vermicular action, certain sacculi contract and dilate alternately ; the transverse constrictions between them shar- ing in the same movement. This alternate movement is often accompanied by an irregular contraction of the longitudinal bands; which is sometimes carried to such an extent, as to shorten the tube, by approximating and di- lating certain of its cells. And even where the effect of the local irritation survives its cause, so as to excite a continuous movement which proceeds along a considerable length of intes- tine, still it rarely affects all the cells of the bowel exactly alike; but often passes lightly over one or two, to bear with increased inten- sity on those which immediately succeed them. Very similar movements are produced by galvanizing the solar plexus which gives off the nerves to the large intestine. On the whole, therefore, the greater solidity of the contents of the large intestine implies a greater resistance to the contraction of its muscular coat. And the structure of this coat shows no proportionate increase, but rather a decrease of strength. Hence we might almost conjecture, that the general movement of the small intestine is here ex- changed for one which is slower, feebler, and hence less effective : and which, besides being much weaker, is possibly interrupted by longer periods of rest.y But it is probable that this comparatively feeble character of the general movement of the large intestine is capable of being more than compensated by that heightened efficacy which the peculiar arrangement of its mus- cular coat can concede. The thin muscular stratum that forms the wall of its numerous pouches, is evidently capable of assuming a much smaller surface, in obedience to the thick and powerful bands of its transverse and longitudinal coats. Indeed, the simul- taneous contraction of these two sets of fibres would convert them into what would form, for the time, a very thick and powerful expanse of unstriped muscle, capable of ob- literdting the entire calibre of the intestine. In this way the same muscular apparatus * The contractions by which this part responds to a local stimulus are far more feeble, slow, and uncertain, than those obtained in any other part of the canal,— the stomach not excepted. This character seems to be a direct result of the tenuitv of the muscular coat, which also attains its maximum here. An incident which I have remarked in one or two cases of intestinal obstruction appears to be partly explained by the same structural peculiaritv. In these instances, though the stricture was seated in the descending colon, the dilatation and rupture that formed the immediate cause of death occupied the caecum. t Compare pp. 343, 344, 368 STOMACH AND INTESTINE. which generally concedes to the contents of the large intestine a long delay, and a slight movement over a large absorptive surface, would still be quite capable of effecting their rapid and vigorous expulsion, when required to do so. Nay, more, since much of this ex- pulsive act seems, as it were, removed from the sacculi themselves, and concentrated in the bands around them, we may conjecture that the mechanism of these latter contrac- tile masses is also specially concerned in the nervous part of the process. At least, it is not impossible, that the irritation or stretching of these two sets of muscles (which can be effected only by the general distention of the calibre of the tube, and not by the local dis- tention of its cells) may constitute the im- mediate stimulus of the evacuation of the whole large intestine, or of any particular segment. The mucous membrane of the colon may be described as only differing from that of the small intestine in the fact that it is somewhat thicker, and quite devoid of villi. Its more numerous tubes are about one-third longer than those of the small intestine ; and their diameter seems to be, in genera!, still more increased. Its solitary follicles are also more numerous, and of larger size. And the depressions which mark the site of each on the internal surface of the bowel are here represented by a distinct pit ; which leads by vertical, or even somewhat divergent sides, to the follicle that occupies its base. But the secretions of these structures, and the cell- growth which lines them, do not present any noticeable difference from their analogues in the small intestine. The rectum (/-, fg. 274. ; r 1, r 2, r 3, Jig. 276.) (formerly straight gut, Eng. ; Mastdarm, Germ.), which intervenes between the sig- moid flexure of the colon (s) and the anus (w), forms the terminal segment of the large intestine. It has received the above name from the comparatively direct course which it takes. Its length is about seven to eight inches. Its width is at first only equal to that of the small extremity of the colon, with which it is continuous : but gradually increases, so as to form a kind of dilatation or pouch in the immediate neighbourhood of its lower aperture. Here it suddenly contracts to the narrow orifice of the anus ; which is situated in the perineal space, that closes the pelvis, and forms the lower extremity of the trunk. Strictly speaking, however, the rectum is by no means straight. Beginning at the left sa- cro-iliac symphysis (e,fig. 276.), it first passes obliquely downwards and to the right side, towards the median line of the trunk; which it reaches at a point that nearly corresponds to the body of the third sacral vertebra (at r 1, fig. 276.). And though, from hence to its termination, it continues to occupy the middle line, still as it rests upon the concave anterior surface of the remainder of the spinal column, it assumes a curve similar to that of the sacrum. It thus acquires a second and more remarkable bend (at r 2, Jig. 276.), which is convex backwards. Finally, at the tip of the coccyx, it quits the antero-posterior direction given it by this bone ; and, bending suddenly Fig. 276. The viscera of the adult male pelvis, as seen after the removal of the right innominate bone : show- ing the situation and relations of the rectum. a, fourth lumbar vertebra; b, bladder; c, sym- physis of the pubis ; d, inner surface of the left osilii; e, sacro-iliac articulation;/, vasdeferens; g, ureter ; h, spine of the ischium sawn through, and left attached by the coccygeus muscle ; i, left vesicula seminalis; " k, prostate gland; /, bulb of the urethra ; m, left corpus .caveruesum divided at its root ; n, anus ; o, levator ani cut across near its attachment to the coccyx ; p. sciatic nerves and vessels ; 9, fibres of levator ani passing round the lower end of the rectum ; r, rectum, 1, 2, 3, its first, second, and third portions ; s, sigmoid flexure of the colon ; r v, peritoneum forming the left side of the recto-vesical pouch. downwards at a right angle, becomes vertical for a very short distance (at r 3, Jig. 276.) prior to ending in the anus. The above successive changes in its di- rection are associated with others, which af- fect its relations to the peritoneum and to the surrounding structures. In accordance with these, it is usual to describe the rectum as subdivided into three portions. The first or oblique segment (between s and r 1, fig. 276.) is about 3£ inches long. It is covered on every side by peritoneum ; which, at its commencement, attaches it to the pelvis by a short meso-rectum, very simi- lar to the meso-colon of the sigmoid flexure.* It lies on the sacrum, the upper border of the pyriformis muscle, and the sacral plexus. In front of it is the bladder, from which it is generally separated by some convolu- tions of the small intestine. On either side * This meso-rectum is sometimes so long, as to give this segment of the bowel a mobility (and often a shape) very similar to that of the neighbouring sigmoid flexure itself. STOMACH AND INTESTINE. 369 it is related to the ureter, and to the branches of the internal iliac vessels. The middle or arcuate segment (r 2, Jig. 276.) scarcely exceeds 2f inches in length. It lies on the sacrum and coccyx ; to which it is attached by a loose areolar tissue, that usually encloses much fat. The peritoneum, which invests a small part of its lateral sur- faces above, soon becomes limited to its anterior surface as it descends; and ceases altogether at a distance of about an inch from the termination of this part of the bowel. This incomplete serous covering is, in fact, the lower extremity of a pro- cess of peritoneum, which is called the recto- vesicul pouch (r v, Jig. 276.). The apex of this, below, corresponds to the point where the membrane is reflected from the anterior sur- face of the rectum, to the neighbouring pos- terior surface of the bladder. Hence the front of the bowel, which, above, comes into contact with the distended bladder, or with any con- volution of small intestine that may chance to occupy the recto-vesical pouch, touches, be- low, the anterior part of the base of the blad- der. This it does in a triangular space, that is bounded on each side by the vesicula semi- nalis (i, fig. 276.), and behind by the pouch aforesaid : — a space, which therefore corre- sponds to the "trigone vesicate" on the inner surface of the bladder ; and marks a region, where this viscus may be punctured through the rectum, without any injury to the serous membrane. On each side of this part of the rectum, is a lamina of pelvic fascia which supports it; and externally to this is the coccygeus muscle, which descends from the spine of the ischium (h,fig. 276.) to the bor- der of the coccyx. The third or terminal portion of the bowel 0' 3'/g- 276.) is about 1| inches long. It is surrounded, above, by areolar tissue loaded with fat: below, by the sphincter ani externus (at n}- and by the levator ani (o and q} which descends from the pelvis to mingle its fibres of insertion with those of the former muscle. In front of it are the prostate (k,fg. 276.) and the membranous portion of the urethra in the male, the vagina in the female: behind it, the tip of the coccyx in both sexes. The degree in which the prostate projects into the rectum will of course vary, both with the size of this gland, and with the amount of dis- tention to which the tube itself is habitually subjected. Where its distention is very great, the flaccid intestine sometimes appears almost folded around the prostate gland, so as to offer a kind of pouch on either side of it. As regards the structure of the rectum, its peritoneal coat has already received a sufficient description. Its muscular tunic differs remark- ably from that of the colon. In place of being divided into three bands, the fibres of the longi- tudinal coat are again collected into a single uniform expanse, that surrounds the whole°of the tube. And both it and the transverse layer are very much increased in thickness. Thus even in the upper part of the rectum, the muscular coat offers a total thickness which at Supp. least doubles that of the colon; while near its termination, it is scarcely less than four times as thick. The fibres themselves are of a red- der colour, especially the transverse; and near the anus, they are mingled with the striated elements of the adjoining voluntary muscles. And that distant analogy which the rectum seems to offer the oesophagus in all these respects, is rendered somewhat closer by the presence of numerous folds of mucous membrane, which the mere passive contrac- tion of its muscular tunic appears generally to produce. In short, it would hardly be an exaggeration to say that this, the last segment of the digestive canal, resumes not only the median position, but even the structure and action, of the first. Muscles of the anus. — The muscular appa- ratus that guards the lower outlet of the rec- tum, consists chiefly of two sphincter muscles, which close the orifice of the anus by their contraction. Of these, one, the sphincter ani internu-Sy which is situated within the bowel, is little more than a thickening of the proper transverse or circular layer of its muscular coat. It lies immediately beneath the mucous membrane, and consists of the ordinary unstriped fibres, which retain their usual pale colour. The other, the proper sphincter, or the sphincter ani externus, is a deep-red mass of striated muscular fibre, which surrounds the lower extremity of the rectum (at w, Jig. 276.), including the pre- ceding structure. Its form is elliptical and con- cave; so that its outer border occupies a higher level than its inner one. Hence it receives the end of the bowel as it were into a shallow funnel; and, on contracting, occludes its cavity by the pressure of what is a surface, and not merely an edge, of its plane of fibres. Its outermost bundles arise from a tendinous structure which is prolonged from the tip of the coccyx; and they pass forwards, on both sides of the bowel, to reunite in the central tendinous point of the perinaeum. Its inner- most or lowest fibres are attached to a dense subcutaneous areolar tissue that lies before and behind the anus. In the female, they interlace anteriorly with those of the con- strictor vaginae, by what is often a distinct decussation. It is chiefly through the intervention of this sphincter that the levator ani muscle is con- nected with the lower extremity of the rec- tum. The fibres of this large expanse of striped muscular substance descend from their pelvic origin*, with an inclination backwards, to reach the lower orifice of the cavity of the pelvis, which they assist to close. In front of the rectum, a certain number of them are inserted into the tendinous and areolar tissues which here occupy the middle line of the peri- neum ; and these join more or less directly with the attachment of the external sphincter in the same situation. Behind the rectum, a considerable plane of the more posterior fibres * For a fuller description of the origin and rela- tions of the above muscle, the reader is referred to the Article PELVIS. B B 370 STOMACH AND INTESTINE. of the levator passes around the tube, return- ing upon itself in the similar portion from the opposite side, so as to sling and sustain the canal. Between these anterior and posterior slips, is a median portion ; which descends to be inseparably united with the upper and outer rings of the external sphincter itself. And besides interlacing with the striped fibres of this muscle, it mav generally be traced sending off a certain number of its scattered bundles, to decussate and disappear amongst the un- striped fibres of the longitudinal and transverse layers of the rectum just at their termination. Movements of the rectum. — The contraction of the muscular coat of the rectum, like that of the other segments of the digestive tube, has for its object the onward propulsion of its contents. But since the rectum ends the intes- tinal canal, it forms the portal by which these contents are altogether dismissed from the body. Health and comfort alike require that this act of dismissal should be both inter- mittent and infrequent. While the mere con- sistence of the faeces is generally such as to demand the application of a comparatively powerful force in order to effect their rapid removal. Hence the entire mechanical action of the rectum is naturally divisible into two stages : — one which propels, and one which expels, the various substances occupying its interior. The latter of these two processes is called defecation ; and, as we shall see, in- volves the aid of various agents which are strictly extraneous to the bowel itself. Those movements of the rectum which are seen in living or newly-killed animals, can only be regarded as confirming the conclusions that might fairly be inferred from the much greater thickness of the muscular coat in this particu- lar segment of the large intestine. When empty, the bowel remains in a state of rest, from which it can scarcely be aroused to peristalsis by the application of any local irri- tation. But when occupied by a moderate quan- tity of faces, it will often respond to a direct mechanical stimulus ; and still more energetic- ally to the electrical irritation of its nerves. On applying the rapid and powerful shocks of the electro-magnetic machine to those large branches of the sympathetic which are distri- buted in the muscular coat of the rectum, a violent contraction of this tube frequently occurs. In this intense but irregular move- ment, we may generally observe a shortening and a constriction : — acts which no doubt re- present the specific contractions that form the functions of the longitudinal and transverse fibres respectively. Thus the bowel suddenly becomes straighter and shorter; and hence appears as though it were jerked downwards towards its most fixed point at the lower open- ing of the pelvis. This shortening is generally accompanied by a less violent and more uniform movement: — in short, by a peristalsis; which offers the ordinary progressive cons'riction, and is evidently the principal agent in the pro- pulsion of the fecal pellets. But both of these movements are very irregular. The former commonly alternates with a relaxation, which appears to pull the rectum upwards, and exag- gerate its curves. While the latter occupies various parts of the bowel with very unequal intensity and duration; and, occasionally, even seems to take a retrograde course. In most of these details, we may observe the same close analogy between the rectum and the oesopha- gus, which has already been remarked in their median and terminal situation, and (to a lesser degree) in the nature and thickness of their muscular coat. The normal movement of the bowel differs from the above in the fact of its being a more exact and co-ordinate action ; and, therefore, a much more effective one. But while obser- vation and experiment both agree in repre- senting it as a peristalsis, which is quite capable of slowly expelling faeces of moderate consist- ence, no'thing is more certain than that it is rarely called upon to exert such an inde- pendent and unaided force. Under all ordinary circumstances, its influ- ence is assisted by the action of various vo- luntary muscles. These ma} be divided into two classes, which differ in their situation and action. The first are those large planes of muscle which form the anterior, lateral, and superior, walls of the belly; and thus, by their contrac- tion, exert a forcible pressure on the intestines contained in this cavity. The second are the similar structures that close the outlet of the pelvis. These have for their office to support the end of the canal. And their muscular nature enables them to effect this support by a texture, the passive or active contraction of which can always increase the reaction or resistance to the abdominal pressure in exact correspondence with the varying demands made upon it. They thus fix the end of the intestinal canal, while it is being emptied of its contents by the pressure of the muscles of the belly. The mechanism of the abdominal pressure having already been described in treating of the act of vomiting*, but little need here be added with reference to the special conditions under which it is called upon to aid that of defecation. Of course the chief of these con- ditions consists in the application of a stimulus to the large intestine itself. And though any irritation of the mucous membrane of the rectum seems capable of producing that vio- lent straining which marks the exertion of the abdominal pressure, still its strictly co- ordinate character is well illustrated by the preference apparently shown to a stimulus which acts directly on the muscular fibres of the bowel themselves. Thus a mechanical distention of the rectum appears to be a more efficient stimulus to the total expulsive act than the application of any ordinary irritant. While, vice versa, there are good reasons for conjecturing, that mere distention of the belly is capable of arousing a sluggish large intestine to expel its contents.f And a * See p. 316. t Such a " reflex action," from the animal to the organic muscle, may perhaps explain the operation of one of the ordinary remedies against constipation ; STOMACH AND INTESTINE. 371 still more frequent association of movement is probably exemplified in the tenesmus pro- duced by dysentery and other disorders, which involve great irritation of the rectum. For the sensations of the patient, and the uncon- trollable impulse which follows them, seem to indicate that the irritation of the mucous membrane is often accompanied by violent contraction of the muscular coat of the in- testine, both of which unite to excite the subsequent abdominal pressure. The nature of the contents of the rectum greatly affects the degree in which the muscles of the abdomen are made to assist in their expulsion. When these contents consist only of gases and liquids, they require so little of this aid, as to be sometimes expelled without it. But the extrusion of hard scybalous evacuations often demands the help of ab- dominal pressure, to an extent such as in- volves all the viscera of the trunk, and seriously obstructs the flow of blood in the larger veins of the head and thorax. As regards the levator ani muscle, its origin and insertion, together with the course taken by its fibres, leave no doubt as to what must be the direct effect of its contraction. It raises the end of the rectum, together with the ligamentous structures of the perinaeum anteriorly, and the coccyx posteriorly. But as the time of this action seems exactly to coincide with the exertion of the abdominal pressure just alluded to, the degree in which it really raises these structures can only equal the surplus of its force over that of the mus- cles of the belly. Hence it may be doubted whether the muscle generally does more than fix the bowel : an effect which is, however, of the highest importance to the mechanism of defalcation. The influence of the neigh- bouring perinaeal muscles is still more obscure. Such being the known agents of the pro- cess of defalcation, we may next attempt to sketch the course of its phenomena. The ordinary peristalsis of the large in- testine propels into the rectum a variable quantity of faeces. These, after a longer or shorter sojourn in its first or second por- tions, excite an active peristaltic contraction of its muscular coat. In general it is only when they reach the lower extremity of the bowel, that the abdominal pressure adds to this peristalsis its far more powerful expulsive force. The combined effect of both these actions urges the faecal mass against the ex- ternal sphincter, which relaxes at this in- stant, by a voluntary effort, so as to permit the extrusion of the descending mass : a small portion of the loose mucous membrane being at the same time generally everted around it. A variable length of faecal substance thus passes through the orifice of the anus. The continuity of the descending mass being finally interrupted, the act of respiration* is resumed ; the abdominal pressure ceases; and at the same time, the contraction of the levator ani, aided by that of the rectum itself, returns the projecting extremity of the bowel into the pelvis, by a kind of sudden and forcible re- traction. The latter act, in which both of the sphincters may be presumed to play an important part, often subdivides a continuous faecal mass ; returning the upper segment thus cut off into the cavity of the rectum which it was just leaving. The total du- ration of the expulsive act appears to be chiefly determined by the consistence of the fasces, the velocity of their transit, and the exigencies of the suspended process of respi- ration itself. The mucous membrane of the rectum is con- nected with its muscular coat much more loosely than that of the colon. Owing to this circumstance, it generally exhibits nume- rous folds. Most of these are mere tempo- rary results of the passive contraction of the muscular coat. And in correspondence with such an origin, they are very irregular in size, number, and position. They are, how- ever, more frequently found occupying the dilated lower end of the bowel, where they take what is usually a longitudinal direction. __ * But in addition to such casual and tem- porary folds, Mr. Houston* has described others, which he states to have a definite direction and situation, as well as a more permanent character. According to this anatomist, three is the number of these folds or valves usually present. The largest and most constant of the three projects from the anterior wall of the rectum, opposite to the base of the bladder, and about three inches above the anus. The valve next above this springs from the left wall of the bowel, about midway between the last and the third or up- permost fold. This latter projects from the right wall of the upper end of the rectum. The shape of all three is nearly semilunar : their depth about half an inch ; and they are fixed by a convex border to about half the circumference of the intestine. And Kohl- rausch-|- has described a fold which tolerably answers to the fourth and least constant of those mentioned by Mr. Houston. He states it to be always present, as a transverse projection from the posterior wall of the rectum opposite the middle of the coccyx. In general it con- tains no muscular fibres : but rarely these may even encircle the bowel, as a continuous ring or third sphincter, which forms the lower boundary of a dilated and sacciform segment of the rectum. As regards these folds, we may point out, that their usual situation corresponds to the most prominent parts of those three curves of the rectum which we have already alluded to. Thus the third answers to that convex mucous surface which marks the namely, the application of a wet bandage tightly * Dublin Hospital Reports, \ around the belly. t « ^ur Anatomic und Fhvsi The way in which this act is affected during the exercise of abdominal pressure has already been explained at p. 316. s, vol. v. p. 163. " Zur Anatomie und Physiologic derBeckenor- gane," Leipzig, 1854 ; also Valentin's " Bericht ueber die Leistungen in der Physiologic " in Can- statt's Jahresbericht, 1854. BBS 372 STOMACH AND INTESTINE. transition of the sigmoid flexure of the colon into the rectum ; the second indicates the spot where the bowel reaches the median line of the sacrum ; and the first is nearly op- posite to its bend in the hollow of the latter bone and the coccyx. And frequent as their presence undoubtedly is — and important as they therefore are with respect to the surgery of the rectum, — it may still be doubted whether they possess those characteristic anatomical features that would alone entitle them to rank as true permanent folds, like the transverse or falciform septa which isolate the several pouches of the large intestine. For, unlike these, they are not only somewhat irre- gular in number and position, but are effaced by complete distention of the tube. And, finally, they appear to contain not a trace of the proper transverse stratum of unstriped fibres. Hence they probably exp/ess a mere passive arrangement of the loose mucous membrane; — a relaxation which is perhaps chiefly due to contraction of the powerful longitudinal layer of the muscular coat of the bowel. In the rectum, the muscular lamina of the mucous membrane resumes its usual thick- ness. At the lower part of the bowel, the skin and mucous membrane become con- tinuous with each other. But, as might be expected from the great dissimilarity of these structures, there is a distinct line of demarcation between the two. Their junction is situate, not exactly at the anus, but at a point from two to four or five lines above this aperture. Here the skin terminates by a wavy margin, having a distant resemblance with that dentate edge, by which the thick white epithelium of the oesophagus adjoins the delicate pink mu- cous membrane of the stomach. And the apex of each of these waves usually corre- sponds to the starting point of a longitudinal fold of mucous membrane ; which, after pro- ceeding a short distance up the bowel, either becomes indistinct and disappears, or is crossed and effaced by others that take a different direction. It is nearly in this situation that Kohlrausch * describes a thin layer of un- striped muscular fibres, lying between the sphincter ani internus and the mucous mem- brane. Traced upwards from their intimate union with the latter structure, these fibres are seen to take a longitudinal course; and to end, about one and a half inches above the aperture of the anus, by joining the layer of circular fibres immediately external to them. Regarding these latter as their origin, it is evident that their action would raise the mu- cous membrane, and oppose its prolapse. Hence they are described as forming a " sus- tentator tuniccB mucosce" Below its junction with the mucous membrane, the moist skin possesses its ordinary structure. And around the anus, it is occupied by numerous hair bulbs ; as well as by sebaceous follicles, which pour forth a large quantity of a peculiar odo- rous secretion. The contents of the large intestine are of * Loc. cit. two kinds. The first is a mass which, usually of a semifluid consistence, ranges from the state of a thin liquid to that of a hard friable solid. This mass, when evacuated from the rectum, constitutes the faeces, ordure, or ex- crement. The second is an elastic or ga- seous fluid, which occupies the intestine in very variable amount, and unless its quantity be excessive, is not necessarily or regularly expelled at all. Fceces. It will be some clue to the compo- sition of the faeces if we recollect, that the large intestine so far resembles the small, as to justify our inferring that it continues the various metamorphoses which the contents of the canal begin to undergo in its upper segments. These metamorphoses are due, partly to a spontaneous decomposition of the alimentary substances themselves, partly to changes set up by the various secretions mixed with them. And they are accom- panied by processes of absorption and se- cretion, which may probably be regarded as in some degree peculiar to this segment of the tube. Of these two processes, that of absorption seems chiefly destined to de- prive the intestinal contents of their more watery and soluble parts. While the act of secretion pours forth fluids which, from their proximity to the end of the bowel, may be assumed to be, in great extent, excremen- titious. The matters thus excreted may be divided, histologically, into two chief con- stituents : — a structureless alkaline fluid which is furnished by the tubes ; and a scaly epithelium, which is a desquamation from the mucous membrane of the rectum. But it would be wrong to suppose that the whole of the processes which engage the contents of the large intestine can be comprehended in three such acts of meta- morphosis, absorption, and secretion as those just alluded to. On the contrary, each of these three exerts its usual complex reaction upon the other two. Thus the soluble re- sults of metamorphosis undergo absorption, as do also some of the substances secreted. The fluids secreted into the bowel no doubt modify the spontaneous changes which en- gage its contents. And, finally, the slow transit of these contents along the intestine is accompanied by the precipitation of in- soluble matters from the various secretions of the upper segments of the canal, prior to their expulsion from its lower orifice. It has indeed been alleged, that the ccecum is the seat of a special metamorphosis, which repeats, as it were, the process of gastric digestion: — that its mucous membrane pours out an acid secretion, which is capable of dis- solving certain constituents of the food pre- paratory to their absorption. But a closer examination dispels this view, and assigns to this segment an humbler office, which is closely analogous to that of the neighbouring portions of the canal. Its tubes, which have precisely the structure of those found else- where, pour out an equally alkaline secretion. Its infusion, whether acidulated or otherwise, STOMACH AND INTESTINE. has no higher solvent power over albuminous substances than that possessed by the similar fluid prepared from pieces of ileum or colon. While the strongly acid reaction of its contents in many herbivorous animals is sufficiently explained as due to that lactic fermentation, which the various starchy substances are so apt to undergo when exposed to spontaneous decomposition at the temperature (about* 103°) of the intestinal canal. Consistently with such an explanation, this acid reaction is found chiefly or exclusively in those parts of the faecal mass which are not in contact with the alkaline mucous membrane, and is by no means limited to the contents of the coecal pouch. We may therefore regard the faeces as com- posed chiefly of two constituents : — which are derived, the one from the food taken by the animal, and the other, from the secretions of its digestive organs. And in like manner, we may" premise what follows by stating, that the composition of any particular excre- ment will always depend on the nature of the food, the state of the secretions, and the na- ture and amount of the metamorphoses which both these constituents have together under- gone. Physical properties of the faces — Subject to circumstances so numerous and fluctuating, it is obvious that the physical properties of the faeces must vary extremely in different sub- jects. Their ordinary colour, odour, form, size, and consistence are so well known, as scarcely to require any special description in this essay. As regards the two first of these characters, the contents of the small intestine are dis- tinctly faecal. But it is only in the coecum, where both their colour and odour become much more marked, that the faeces usually begin to acquire a solid consistence. Their form and size is dictated, partly by the shape and diameter of the bowel (as already alluded -f- to), and partly by the degree in which their consistence has been augmented by the absorption of their watery parts. Where their solidity is much increased from this latter cause," the act of expulsion has little influence in modifying their form. The way in which it usually does this has been previously pointed out. The odour and colour peculiar to the faeces have been ascribed, by some authors, to the bile which enters into their composition ; by others, to the fluids which are poured out into the intestinal canal from the blood-vessels occupying its mucous membrane. It is, how- ever, probable that they are not due to either of these causes exclusively, but depend rather on a combination of both; and are further mo- dified by that admixture of altered (not to say decomposing) food, which forms so large a constituent of the excrement. Thus, that they depend to some extent on the bile, is well shown by those cases of * Brown Sequard, " Experimental Researches in Physiology and Pathology," New York, 1853. t See p. 366. jaundice, in which a deficient secretion of this fluid, or an obstruction of its normal channel, has arrested its flow into the intestine. For in such instances, the ordinary brownish yel- low tint, and faecal smell, proper to the excre- ment, are exchanged for a greyish white co- lour, and an intensely putrefactive odour. But it is certain that, unless the bile be poured out in excessive amount (as after the exhibition of mercury *), or conveyed through the bowels with unusual rapidity (as in diarrhoea and purging), it is but a small fraction of its total quantity that escapes re-absorption, so as to be found in the fasces. This statement especially applies to the meconium which occupies the intestine of the foetus. At any rate, this substance contains but little of the acid or the colouring matter of ordinary bile. Now, the preparation of excrement by the foetus, and by hybernating or starving animals, is a satisfactory proof that its specific faecal characters are not essentially due to any modifi- cation of the alimentary matters contained in the intestinal canal. And since the bile forms but a small portion of its mass, it is evident that much of it must be derived from the se- cretions of the digestive tube itself, and that its properties must be partially due to the same source. Indeed, this intestinal constituent, which is probably always a large ingredient of the faeces, becomes, in the hybernant and the foetus by far the largest : — so much so, that the dried meconium contains about 85 to 95 per cent, of epithelium and mucus, al- most all of which must be referred to this source. While, as regards its physiological import, it is impossible to doubt that it is (/car* i^oxr) v) the excrement : — that it is, in fact, the chief excretory ingredient of the faeces ; and hence that ingredient, the dismissal of which from the intestinal canal is most essen- tial to the welfare of the organism generally. The above view, as to the share which both the biliary and the intestinal constituents take in producing the colour and odour of the faeces, appears so irrefragable, that we may content ourselves with a passing allusion to those experiments by which it has been at- tempted to establish the predominant or exclu- sive influence of either. Thus, while it has been pointed out by Valentin -f- that putre- fying bile diffuses the strongest smell of or- dure, LiebigJ states that he has succeeded in the artificial production of the faecal odour by a process which essentially consists in imper- fectly oxidizing some of the more azotized tis- sues of the body. The latter experiment has been regarded as leading to the inference, that * The green colour of the stools after calomel has been taken seems to be due, partly to the chemical reaction of the contents of the intestine, partly to an increase in the quantity of bile poured out. The latter fact has been confirmed by experiments, in which this drug has been administered to dogs pro- vided with biliary fistulas opening externally. The chemical change "undergone by the mercury in the intestinal tube consists (like that of the "salts of iron under similar circumstances) in the formation of a sulphuret of the metal. f Lehrbuch der Physiologic, vol. i., p. 370. J Animal Chemistry, 3rd ed., p. 148. et seq. BBS 374 STOMACH AND INTESTINE. certain effete constituents of the blood are secreted into the intestine, in a like state of partial oxidation. But, even could we assume the chemical identity of two substances merely from their having the same overpowering smell, we should still be left in uncertainty, as to whether these odorous matters were excreted directly from the blood into the bowel, or were introduced into it indirectly, by means of the secretion and subsequent metamorphosis of the bile. The very large intestinal constituent of the meconium, associated as it is with an almost inodorous character of this excrement, would indicate that, on the whole, Valentin's view of the biliary origin of the faecal odour is the more correct one. At present, however, a satisfactory decision of the question seems impossible. But whether the peculiar odour of the faeces be biliary or intestinal, there can be no doubt that it is derived, in the first instance, from the blood. For the smell of the excrement of any particular species always has a close relation to that odour, which is specific to the body of the animal, and which appears, in va- rious degrees of intensity, in all its different excretions. And it is even stated by Wehsarg* to present differences specific to the individual. Finally, we need have little scruple in as- serting, that all the physical properties of the faeces are also in a great measure dependent on that alimentary residuum which usually enters so largely into their composition. The quan- tity of fatty matter and of casein usually pre- sent in the excrement of the sucking-child, the deepening (and finally black) colour of the faeces in persons who feed chiefly on vege- tables, the lactic acid found in the evacuations of carnivora, or the oil which may often be de- tected in the stools of persons by whom even small doses of cod-liver oil are being taken medicinally — form instances of this kind, which might obviously be multiplied to almost any extent. Nor is the process always li- mited to a mere admixture or decomposition of the food itself. On the contrary, the metamorphoses which most of its ingredients have to undergo, often react on the secretory contents of the canal, so as to modify their appearances by the addition of properties more or less foreign to them. And nothing but that comparatively uniform admixture of the chief alimentary principles of the food, which we shall hereafter find is absolutely necessary to the life of the individual, will account for even the imperfect uniformity traceable in examining the excrements of large numbers of individuals. The reaction of the human faeces is gene- rally acid; sometimes neutral or alkaline. The quantity daily evacuated by a healthy male adult may be estimated as amounting, on an average to about five ounces avoirdupois. The specific gravity of the faeces is gene- rally greater than that of water, owing to the solids which they contain. But it is far too variable to allow of any average estimate * Microscopische und ChemischeUntersuchungen der Fasces gesunder Menschen. Giessen, 1853. being made. For it varies, not merely with the bulk and weight of the alimentary resi- due that forms so large a portion of the or- dinary excrement, but also with the degree in which the faecal mass has been condensed by the absorption of its watery constituents. And it would further seem, that the faeces are capable of being partially dried, and rendered much lighter, by a mechanical admixture of intestinal gases with th/eir substance while still within the body. At least it is very common for different portions of the same evacuation to exhibit very different specific gravities: — the first portions of the excre- ment, which previously occupied the lower extremity of the rectum, being much lighter than water; while those subsequently extruded, though less solid, are so much heavier, as to sink rapidly in this liquid. The mechanical composition of the excre- ment might almost be deduced from what has already been said of its origin. A large quantity of its mass no doubt consists of un- digested food.* This must, however, be sub- divided into two parts, which have a very different import with respect to the digestive function. One of these, which is usually much the larger, includes all those substances that are incapable of being dissolved by the various secretions poured into the intestinal canal. Such are the harder parts of various animal and vegetable tissues : — the sarco- lemma of muscular substance, the cells of car- tilage, fragments of bone, the elastic fibres of areolar tissue ; together with the husks, shells, pods, chlorophyll, epidermis, and various dense membranes, cells, vessels, and fibres of the various fruits and seeds used as food. Some of these tissues quite defend the soluble contents they enclose. The other portion consists of substances which, though really capable of solution in the alimentary canal, have escaped this process: — whether from having been taken in too large a quantity, from not having sojourned in the tube during a sufficient interval of time, or from having been exposed to secretions which are par- tially devoid of their proper solvent force. Of these three causes of such an admix- ture, the first is the more common, and pro- bably constitutes an invaluable safeguard against the dangerous results which might otherwise follow every act of over-eating. Hence in the state of repletion, whether relative or absolute, large quantities of fat, muscular fibre, albumen, casein, starch cells, fibrous tissue, and other strictly alimentary substances, escape digestion, and are found in the faeces. And conversely, it is highly probable that individuals (as well as animals) may have their digestive powers so raised by * The analyses of Wehsarg assign to the dried substance of this constituent an amount which would probably be equivalent to a proportion of about 13 per cent, of the whole excrement. But we may suspect this to be rather too low an esti- mate; and are at any rate justified in doubting whether the alimentary ingredient could be com- pletely isolated, for the purpose of being thus de- termined. STOMACH AND INTESTINE. 375 hunger and need, as to be enabled to extract nutriment from substances that would other- wise defy the action of their gastric and in- testinal juices. In short, these undissolved and insoluble — undigested and indigestible — constituents of the alimentary residuum may almost be said to merge into each other, ac- cording to the habits of the individual with respect to the ingestion of food. That element of the faeces which is derived from the digestive organs of the animal itself, consists chiefly of mucus and precipitated bile. This mucus is, for the most part, structure- less ; but is mixed with variable quantities of scaly epithelium from the rectum in the neigh- bourhood of the anus. In violent diarrhoea, columnar cells from the intestine may also be found in the evacuations : — sometimes in the younger cell-form of abortive cytoblasts or nuclei, sometimes in the more advanced state of simple ovoid cells. The latter are sometimes met with in small numbers, even in healthy faeces ; and constitute what are often termed mucus-corpuscles. The biliary constituent is found chiefly in the form of minute amorphous masses or molecules of a resinous character; crystals or plates of cholestearine ; and soluble colouring matter, that often stains the cells just mentioned, as well as the other mechanical constituents of the excrement. The crystals of ammoniaco-phosphate of magnesia, which are so often found in the faeces, can hardly be definitely allotted to either of the two foregoing sources. They are easily recognised by their characteristic shape. They were formerly supposed to be peculiar to the stools of diarrhoea and typhus. But they are found in the healthiest fasces. Their occurrence appears to be favoured by all circumstances which further decomposi- tion. They are therefore probably due to the action of ammonia (developed in the faeces before or after their expulsion) upon that neutral phosphate of magnesia, which we shall see forms so large a proportion of the entire saline constituent of the excrement. The chemical composition of the faeces will of course exactly correspond with the nature and amount of those substances of which it forms the mechanical admixture. Hence, not only is it impossible to lay down any average that can apply to faeces generally, but it is even probable, that no two specimens of excre- ment are composed of the same proximate constituents mingled in the same proportions. Berzelius* analyzed the faeces of a labourer who had fed on coarse, hard-baked bread, with moderate quantities of meat and vegetables. He obtained the following results : — Water 75'3 Bile ... -9 Substances soluble in water f Bile . . . -9 \ soluble J Albumen . -9 f . . . ) Extractive 2 7 ( (. Salts . . . 1-2 ) jintes- ) in, fat, V 5-7 Insoluble residuum of the food Insoluble substances added in the intes- tinal canal : mucus, biliary resin, and sundrv animal matters 7-0 14-0 102-0 * Lehrbuch der Chemie. Bd. ix. p. 341. "Without, however, impugning the accuracy of an analysis conducted by such an eminent chemist as Berzelius, it seems important to point out that, for physiological purposes, it is all but useless. For not only does it afford no inference as to the quantitative composition of the faeces generally, but it even suggests grave doubts as to the correctness with which its own chief results have been grouped toge- ther. Recalling, for example, our subdivision of the constituents of the faeces into alimen- tary and secretory, we inquire in vain how much of the soluble albumen and extractive of this analysis was derived from the food, and how much may be ascribed to the secre- tions poured into the canal. In like manner we are ignorant whether its fatty constituent was not partly the undigested residue of fat which had been introduced with the food. But from a comparison of this analysis with some observations on the meconium by Hoefle* and Lehmannf, we may conjecture, that while the protein compounds found in healthy ex- crement belong almost exclusively to the food, a small quantity of its elain and margain, and a larger amount of its muco-gelatinous ex- tractive, are derived from the secretions of the animal itself. The inorganic constituents of the excre- ment must also vary greatly with the nature and amount of its alimentary residuum. Porter;}; states that healthy faeces, when dried, contain on an average about 6-7 parts per cent, of mineral substances. Wehsarg reckons these salts at 4'1 per cent., from an average of seven analyses. But an analysis by Dr. Percy § estimates them at 16*4 per cent. This proportion somewhat approaches that given in the analysis by Berzelius quoted above. It also corresponds with some ana- lyses by Macaire and Marcet || of the faeces of the Dog and Horse, which they found to contain 20 and 25 per cent, of ash respec- tively.^ The soluble salts form between one- fourth and one-third of the whole ash. The phosphates of the earths and alkalies consti- tute about one-third of all the salts present. While the chlorides of the alkalies are reduced to the very small proportion of about one- thirtieth ; a proportion which is about equalled by the whole of the sulphates. The chief re- maining peculiarities worthy of notice are, that the quantity of potash is from 10 to 40 times greater than that of the soda ; and that the magnesia reaches half the amount of the lime. Of these two quantitative disproportions, the first seems due to the food; while the latter has been referred by Berzelius to the more active * Chemie und Mikroskop am Krankenbette, p. 85. f Op. cit, vol. ii. p. 135. i Annalen der Chemie und Pharmacie, bd. Ixxi. p. 109. § Day's Simon's Chemistry, vol. ii. p. 375. I Socie'te' d'Histoire Xaturelle de Geneve, vol. v. p. '230. ^[ This difference, like that of the nitrogen of the excrement in these animals (4*2 per cent, in the Dog to -8 in the Horse), probably depended on the con- trast between the animal and vegetable nature of their food. B B 4 376 STOMACH AND INTESTINE. absorption of lime than magnesia in the intes- tinal canal. Carbonates of the alkalies are found in the ash of human excrement ; but they are apparently almost absent from that of the Sheep, Cow, and Horse. They are pro- bably produced by a combustion of some or- ganic salts of these bases. The elementary analyses of the faeces hither- to made possess little physiological signifi- cance, or general validity. But from what has already been stated, it is obvious that the entire excretory part of the ordure removes from the body very little water or nitro- gen ; — probably not more than g^th or ^th of that quantity of each of these elements which is daily excreted in the urine. The time during which the contents of the intestinal tube sojourn in its different segments is probably a very uncertain as well as variable one. In diarrhoea, the whole canal is some- times traversed by these contents in two hours ; while in obstruction, weeks or months may elapse without their complete transit. The mean rate which lies between these two morbid states can only be conjectured. But there are reasons for supposing, that the food of a healthy adult occupies about twelve hours in passing through the small intestine. While from thirty-six to sixty hours may be assumed as its average sojourn in the large intestine, prior to its ultimate expulsion from the rectum. Intestinal gases. — In speaking of the elastic fluids which are generally contained in the large intestine, and are occasionally expelled from its lower orifice, it will be advantageous to contrast them with the gases found in other parts of the alimentary canal : — viz., in the stomach and the small intestine. Many years ago the composition of these gaseous contents of the canal was correctly given by Jurine, from an examination of the corpse of an idiot soon after death by cold. But it is to Magendie* and Chevreul that we owe the only trustworthy quantitative analyses on the subject. Their observations were made upon the gases found in the bodies of criminals im- mediately after their execution. Some authors have therefore thought it worth while to al- lude to their results, as being probably affected by the dyspepsia which the dread of such an impending doom might be supposed to have produced in these unhappy persons. With- out, however, assigning any definite value to this contingency, it is enough to say that they still remain far preferable to any other such analyses: — to those, for instance, of Chevilloff", whose rather different results are quite ex- plained by the time after death to which his examinations were deferred, and the decom- position which had therefore begun, both in the tissues of these corpses, and in the ali- mentary and secretory contents of their in- testines. We may best arrange these analyses in the following tabulated form : — Composition by Volume. Whence obtained. Oxygen. Nitrogen. Carbonic Acid Hydrogen. Carburetted Hydrogen. Sulphu- retted Hydrogen. Stomach ll'OO 71-45 14-00 3-55 _ . Small intestine : average of three \ analyses - - -j - - 31-84 29-80 38-36 - - - - Co3cum - » 67-50 12-50 7-50 12-50 traces. Large intestine j 2' I - 51-03 18-04 43-50 70-00 11-06 5-47 11-06 traces. Rectum - . 45-96 42-86 - 11-18 traces. Flatus expelled per anum (mean of ) tAvo analyses by Marchand) - j - - 21-5 40-5 18-75 18-75 •5 It is only from such analyses that we can form any reasonable inference as to the origin of the gases to which they refer. In making such an inquiry, four sources of aeriform matter at once suggest themselves ; either of which seems at first sight capable of at least partially explaining the presence of gaseous substances in the digestive canal. And the claims of each of these must be separately examined before we can conjecture the proba- ble amount of its product, or its share in those reactions which the physical properties of gaseous fluids so easily allow them to excite. 1. Air may be introduced into the intestinal canal from without the body. Just as some of the lower animals can distend the abdomen by a voluntary deglutition of air, while even the higher Mammalia have been noticed to fill the stomach with air by the movements which precede the act of vomiting, so per- sons have been observed to swallow air, and afterwards expel it by eructation. And apart from such exceptional cases, there is good reason for believing that the ingestion of food always introduces into the stomach an ap- preciable quantity of atmospheric air ; part of which is perhaps mechanically carried down with the alimentary bolus, while another part enters the organ in a state of more minute di- vision, with the frothy saliva. The air which is thus introduced into the stomach will doubtless here undergo a certain amount of diffusion or interchange with the elastic fluids dissolved in the liquid blood that * Precis Elementaire de Physiologic, vol. ii., p. 113. f Chevillot's figures (Berzelius' Jahresbericht der physischen Wissenschaften, 1831, p. 247) indi- cate that, in the diseased and decomposing bodies he examined, oxygen was always present ; and carbonic acid rather increased ; while the nitrogen sometimes reached the large proportion of 99 per cent. STOMACH AND INTESTINE. 377 circulates in the capillaries of the organ. And this diffusion probably imitates that which takes place between the air and the blood at the surface of the lungs and skin. It will therefore convert the gaseous mixture of the atmosphere into one containing less oxygen, and more carbonic acid ; the extent of the change in both these respects varying chiefly with the duration of its sojourn in the stomach. But a number of circumstances unite to prove that the gases of the stomach are in great part derived from some other source. Thus the quantity of air taken with the food can be but small." \Vhile percussion and aus- cultation show, that the cavity of the healthy organ is often largely distended with gas. And the above analysis further points out, that not only is the increase of carbonic acid dispro- portionate to the decrease of oxygen, and therefore (unlike the interchange in the skin and lungs) not due to a mere physical pro- cess of diffusion, but that a new element, hydrogen, has been added to it. The same arguments apply still more for- cibly to those gases, which almost invariably distend the intestines. For during diges- tion, they could hardly pass the pylorus; and at any other time, would be very unlikely to enter the stomach, through which alone they could reach the duodenum. Hence in the case of the intestinal segments of the canal, we are referred almost exclusively to those sources which, we have already seen, will be necessary to explain the greater part of the gas present in the stomach. 2. Gases may be developed in the alimen- tary canal from the decomposition of the food which it contains. Difficult as it is to decide on the evidence at present before us, there seem to be valid reasons for regarding this as the process by which the intestinal gases are chiefly, if not ex- clusively, set free in the alimentary cavity. The food introduced into this cavity is speedily converted into a decomposing mass, which is useful to the organism solely by virtue of the metamorphoses it is undergoing. And though these metamorphoses generally seem to be limited to processes, by which elements are merely re-arranged in the solid or liquid form, and not given off as gases, still they are easily susceptible of being carried further, so as to involve a more or less copious evolution of gaseous fluids. Now, the putrefaction of the protein com- pounds of the food, together with the fermen- tation of its hydrates of carbon, would amply account for these gases; as well as for the ammonia which has been alluded to as pro- bably throwing down part of the soluble phosphates of the intestinal contents, in the form of crystals of the triple phosphate of am- monia and magnesia. For not only are all the gases in the above analyses producible by the various processes of putrefaction external to the body, but their proportions to each other are precisely those which might be expected from the known composition of the food. The conditions which favour the presence of these gases remarkably confirm this view. Too large a quantity of food — and especially ' of food that consists of substances which are either putrefying or fermenting, or are pecu- liarly liable to undergo these changes — noto- riously increases the amount of gases thus generated in the bowels. The liability of cattle to a dangerous distention of this kind, when surfeited with green food, is well known to agriculturists. And in like manner, an increased quantity of sulphuretted hydrogen is generally expelled in the flatus of animals which have been fed upon* beans, or made to take sulphur with their food. While the practice of medicine acquaints us with the fact, that all circumstances which lower the tone of the alimentary canal, or lessen the energy of its secretions, further these sponta- neous (though abnormal), metamorphoses of its contents ; and thus give rise to a corres- ponding increase in the quantity of the gases which form their direct result. We may per- haps find an additional confirmation of this view in a comparison of the various instances analyzed above. At least, the great devia- tions which they exhibit, seem better expli- cable by the variable composition of the food, than by any theory which would refer their development to the organism or the blood itself. Finally, it is well known that the complete exclusion of food from the digestive cavity often gives rise to a peculiar white and con- tracted state of the tube, which implies an entire absence of all such gaseous contents from the greater part of its length. This appearance is so generally seen in the bodies of animals after long fasting, as to constitute an important feature in the medico-legal evi- dence of death by starvation. 3. It has been supposed that gases are set free in the intestinal canal by a kind of secre- tion or transpiration from the blood. But in alluding such a process, it is neces- sary to premise that, strictly speaking, it would hardly deserve the name of a secretory act. Even assuming that it really discharged the gases of the blood into the intestinal canal, we should scarcely be warranted in terming their passage a true process of secretion. On the contrary, all analogy indicates that it would rather constitute an act of diffusion : — a diffusion which would probably obey the same laws, and exhibit somewhat of the same course, as that which chemistry has success- fully investigated in the case of "the lungs and skin. In any case, unless we suppose the capil- laries of the intestine to be the actual site of an unexampled generation of gas from the con- stituents of the blood, an inquiry into these latter will probably afford us some grounds on which to accept or reject the above theory. It is therefore important to point out, that some of the gases found in these analyses — viz. hydrogen, carburetted hydrogen, and sul- * The legumen of which contains much of this element. 378 STOMACH AND INTESTINE. phuretted hydrogen — have never yet been detected in any appreciable quantity in the blood. And hence without assuming their complete absence from this liquid, we may at least infer that they are not present in that amount which would be necessary to explain their secretion from it, to the extent men- tioned in these observations. To this we may add, that no parallel to such a process of gaseous excretion can be observed in the case of any other vascular surface. This statement not only holds good of the serous membranes, but (what is much more conclusive) even of those structures which are specially organized with reference to the giving out from the blood of certain of its gases, and the taking up of others from the surrounding air. It is to the skin and lungs that we should naturally look for evidence of the true secretion of excrementitious or noxious gases from the circulating fluid. And yet, on turning to the results afforded by the eudiometric researches of a number of ob- servers, we find that the gases which we have just stated to be absent from the blood, are equally deficient in the air exhaled from the vessels of these special organs of gaseous excretion. While even the carbonic acid and nitrogen of the intestinal flatus are at once distinguished, by their quantitative relations, from the same gases, as found in the air of expiration. Thus the minute amount of nitrogen in the air exhaled from the lungs is contrasted with an average of 40 per cent, in the gases contained in the intestines; and its proportion to the carbonic acid present, is increased from T^th in the former, to £d, or even f ths, in the latter gaseous mixture, In conclusion, we may point out, that while the carburetted and sulphuretted hydrogen, as well as the pure hydrogen, of these analyses, can only be explained as the result of a pro- cess which directly or indirectly involves the deoxidation of water, — the chemistry of the organism seems always to reverse this process. Far from deoxidating this liquid, there are good grounds for supposing that a quantity of water amounting to nearly £th of the whole aqueous contents of the food is daily formed in the body by a combustion (or in other words, by an oxidation) of the hydrogen of its tissues/ But some will perhaps think that these con- siderations are sufficiently answered by facts, which deserve more reliance than any such arguments. They would possibly instance experiments like those made by Magendie * and Girardin, and confirmed by Frerichsf : in which the de- ligation of an empty portion of intestine had nevertheless been followed by its distention with flatus. Or they might call attention to the tympanites of typhus fever, and other kindred disorders, in which little food has been taken for a long period of time. But a little reflection might teach us that none of these instances have absolutely excluded the presence of all alimentary substances; and that a very small quantity of liquid or solid matter would probably be quite sufficient to yield the gases observed. 4. Lastly, as regards the intestinal gases present in diseased subjects, we may conjec- ture a fourth source of such elastic fluids : — namely, the decomposition of the various secretions of the canal. For it is not too much to assume, that the decomposition to which the alimentary contents of the intestine appear to be often exposed, is sometimes shared by the secretions poured into its* cavity ; especially when we recollect that, in many dis- eases, the state of all the fluids of the organism is frequently such as notoriously favours the access of putrefaction in the tissues after death. The gases expelled from the large intestine carry with them the odorous principles of the excrement. It is, indeed, probable that they become impregnated with these volatile sub- stances mechanically, as a necessary result of their contact with them in the bowels. But reasons are not wanting for the conjecture, that the introduction of certain foetid substances into the blood, is subsequently followed by their specific determination to the mucous membrane of the intestinal canal ; which thus forms a channel for their elimination from the system. For after the inhalation of any par- ticularly offensive odour, the faeces and flatus often exhibit what is unmistakeably the same smell, in a very concentrated form. And the active diarrhoea which frequently attends this reproduction of the odour, seems a part of the same effort of nature, towards the removal of what other evidence, beside that of our senses, thus testifies to be an active poison. Respecting the laws which regulate the forcible expulsion of these gases from the stomach or intestines, little need here be said. Though greatly influenced by habit, still the act is essentially voluntary. Its mecha- nism is so closely akin to that of defalcation as not to require any separate notice. Whether the immediate stimulus to this expulsive act is always mere intestinal distention, or whether it is sometimes determined by the quality (as well as quantity) of the elastic fluids, cannot at present be decided. We are equally ignorant as to how far, fail- ing such an expulsion, these gases are capable of being absorbed into the blood ; and if so, where they emerge from the vascular system, or what form they assume in doing so. The small quantity of sulphuretted hydrogen really present in the most offensive flatus, and the comparative harmlessness of carburetted hy- drogen in the proportions in which it would be dissolved by the blood, prohibit us from coming to any conclusion based on the ordi- nary physiological action of these two gases. We can but conjecture, that whatever ab- sorption they may undergo is slow enough * The cases of physometra adduced by obstetric Rechercb.es physiologiques sur les gaz intes- authors seem to be examples of a similar decoinpo- tinaux. 1824. sition occurring in the blood and secretions con- r °P- «*» P- 8°°- tained in the cavity of the uterus. STOMACH AND INTESTINE. to allow of the much quicker destruction of their poisonous properties by a more or less perfect oxidation. Arteries of the intestines. — We have seen that the stomach and duodenum are supplied with arterial blood by means of various twigs derived from the three branches of the coeliac axis, which springs from the upper part of the abdominal aorta. The remainder of the intestinal canal is furnished with arteries which are given off by two large branches of the abdominal aorta. These branches are named, from their position and distribution, the superior and the inferior mesenteric. The superior mesenteric artery (a, fig. 277.), the longer of these two branches, is distributed over that large segment of the intestine which is formed by the lower part of the duodenum, the whole of the jejunum, ileum, and ccecum, and the first two-thirds of the colon. The Fig. 217. Distribution of the superior mesenteric artery to the small and large intestine. a, trunk of the superior mesenteric artery ; b, ileo- colic artery ; c, its iliac branch ; d, its colic branch ; e, right colic artery; /, middle colic artery; g, arches formed by the anastomosis of the branches to the small intestine ; p, pancreas ; du, duodenum ; j, jejunum; i, ileum ; c ee, caecum; ac, ascending colon ; t c, transverse colon ; d c, descending colon. trunk of the vessel comes off from the aorta, at a point which about corresponds to the upper border of the second lumbar vertebra. It is separated from the coeliac axis by the pancreas ; and hence is distant about a third of an inch from the origin of the latter vessel. From this commencement, it passes down- wards and forwards, crossing over the termi- nation of the duodenum, so as to reach the upper part of the mesentery. It now con- tinues downwards between the two layers of this fold of peritoneum, which it occupies near 379 its attachment to the posterior wall of the abdomen. Hence its length and direction correspond to those of the attached border of the mesentery itself ; and are such, as to conduct it downwards and obliquely towards the left side, to a termination that corresponds to the end of the ileum, or the commencement of the coecum. But the branches given off to these latter segments of the intestine by the trunk of the vessel are so large, and so directly continuous with its previous course, that it is only in a very arbitrary and limited sense that we can speak of it as ending in this situation. The arrangement of the larger or primary branches of the superior mesenteric artery is liable to great variation, but is generally as follows. The trunk of the superior mesenteric artery is directly continuous with a large vessel (6, Jig. 277.), which, when it has reached a dis- tance of about two inches from the coecum, divides into two others; of these the upper (d,fig. 277.) passes towards the ccecum, and the lower (c,fig. 277.) towards the ileum. Thei/eo- colic artery (b,fig. 211. \ as the common trunk is named prior to its bifurcation, usually gives off from its right side one of rather smaller size, about three inches from the border of the bowel. The latter, which is called the arteria colica dextra, or right colic artery (e,Jig. 277.), often arises by a separate trunk from the superior mesenteric. It takes a course almost horizon- tally outwards, or towards the right side, lying underneath the single layer of perito- neum which covers in the ascending colon, so as to reach this part of the large intestine at or near the middle of its height. Finally, at a dis- tance of little more than an inch from its entering the mesentery, the trunk of the supe- rior mesenteric artery gives off a large branch, the arteria colica media (f,Jig. 277.), which passes upwards and back wards, enters between the two layers of the transverse meso- colon, and is distributed to the transverse colon, which it reaches at the middle of its posterior border. Besides these named branches, the superior mesenteric gives off numerous arte- ries (at g, fig. 277.), of almost equal size, which have not received any special designa- tion. These twenty or thirty branches leave the left side of the artery, at various points between the lower border of the duodenum and the origin of the ileo-colic artery ; and pass outwards, or to the left side, towards their distribution on the small intestine. The further course of all these branches towards the small and large intestine affords a remarkable ; instance of an arterial ana- stomosis ; such as is almost unparalleled in the whole of the body for the freedom and frequency of its communications, and the size of the^vessels by which they are effected. Each of the primary branches just alluded to bifurcates: and its two resulting branches unite with those above and below them, so as to form a set (g,/g-277.) of arterial arches ; from the convexity of which spring new trunks, to divide and inosculate in a similar manner. This arrangement, which prevails 380 throughout all the mesenteric branches that supply the intestine, is carried to such an ex- tent in the jejunum and ileum, as to offer, in many parts, four or five successive sets of arches ; which become smaller and more nu- merous as they approach the bowel, and finally give off the minute arterial ramifications that enter and traverse the intestinal coats. On reaching the intestine itself, the greatly diminished arteries break up into still smaller capillary branches. These inosculate freely with each other, by comparatively large branches of communication ; and thus unite and anastomose to form a dense stratum or flattened network of vessels, which occupies the layer of loose areolar tissue that separates the muscular from the mucous coat. This vas- cular plexus gives off, on the one hand, the vessels of the mucous membrane ; and on the other, the not very numerous branches which run between and amongst the unstriped bun- dles of the muscular coat. The inferior mesenteric artery (6, fig. 278.), which supplies the descending and sigmoid portions of the colon, and the whole of the rectum, is also a branch from the aorta. It arises from the front and left side of this vessel (a, fig. 278.), about an inch below the place where it gives off the left renal artery, and nearly the same distance above its bi- furcation into the two iliac vessels. From this origin it is directed downwards and slightly outwards, lying successively on the aorta, the left psoas muscle, and the left Fig. 278* STOMACH AND INTESTINE. Distribution of the inferior mesenteric artery to the large intestine. a, abdominal aorta ; b, inferior mesenteric artery ; c, left colic artery ; d, artery to the sigmoid flexure ; e, superior hsemorrhoidal artery; /, middle colic artery; g, large communicating branch between the left and middle colic artery, sf, sigmoid flexure of the colon ; r, rectum, (t c, a c, p, du, as in fig. 279.) * In several of the preceding microscopic figures, the artist has been indebted to Koelliker's beautiful woodcuts for some details, which require this spe- cific acknowledgment. common iliac artery. During this part of its course, it lies at some distance from the in- testine. But below where it crosses the com- mon iliac vessels, it occupies the double fold of peritoneum (mesa-rectum) that attaches the rectum to the pelvis. This terminal portion of the vessel, which is called the superior hce- morrhoidal artery (e,fig. 278.), is continued to a point about opposite to the middle of the sacrum ; where it ends by bifurcating into two branches, which ramify on the opposite sides of the bowel, and are distributed to its various coats. These branches inosculate freely with the ramifications of the middle hcemorrhoidal artery, which is itself given off to the rectum by the internal iliac artery, or some of its branches. The only named branches of the inferior mesenteric are the left colic or arteria colica sinistra (c, fig. 278.), and the artery to the sigmoid flexure (d,fig. 278.). The former of these two vessels passes upwards and out- wards, across the psoas muscle and left kidney, to reach the descending colon at about the middle of its height. The latter, which is sometimes double, also crosses the psoas, to enter the short meso-colon which attaches the sigmoid flexure of the bowel. The fur- ther distribution of both these arteries pre- cisely recalls that of the similar colic branches from the superior mesenteric : each bifurcating into two branches ; which, by uniting with the similar trunks above and below, form the origin of a set of arches that ramify in a second and third series. And as the union of the upper twig of the colica sinistra with the lower or left branch of the colica media unites the superior and inferior mesenteric arte- ries by a large anastomosing vessel (g,fig. 278.), all the arches of both these trunks have the most complete anastomosis with each other. So that it would be easy to trace out a con- tinuous arterial channel of large size ; which begins as the superior mesenteric, and passes through the ileo-colic, left colic, median colic, and sigmoid branches, to end in the superior haemorrhoidal artery. Veins of the intestines. — The veins of the intestinal canal are chiefly characterized by the fact, that the trunks formed by their convergence and union do not open into the right auricle, like the veins of the body gene- rally ; but undergo a second ramification and distribution, in their course from the capil- laries of the intestine to the right side of the heart. This arrangement of course influences their distribution at two successive stages of their course. In the first place, their 'larger trunks fail to exhibit that close correspond- ence with the arterial channels which is seen in the case of most other parts of the body. And, secondly, instead of seeking the large vessels on the spine, these trunks converge into a single channel, the portal vein («, fig. 279.), which passes upwards to the liver at some distance from the aorta and primary in- testinal branches,* * See Art. VENOUS SYSTEM. which leave the intestine, and gradually unite into the vessels that converge to form the various trunks. These branches have a tole- rable correspondence with the primary rami- fications of the arteries from the coeliac axis and the two mesenteric vessels. Many of Fig. 279. STOMACH AND INTESTINE. 381 The veins of the intestines commence by a third portion of the duodenum, it swerves dense network, that receives the minute towards the right side, from what was hitherto venous radicles into which the capillaries of an almost vertical course upwards ; and after the mucous and muscular coats return their crossing in front of the duodenum at nearly blood This plexus has the same submucous a right angle, ends by joining the splenic vein situation, and flattened shape, as^ the cor- behind the pancreas. This junction glves responding arterial network already men- rise to the portal trunk (a, fig. 279.). tioned; but, like the venous system in general, The inferior mesenteric vein (e, fig. 279.), is composed of more numerous and larger -the origin of which also corresponds to the branches. It gives off a number of veins ; region supplied by the artery of the same name — generally commences as a single trunk at or near the border of the pelvis. From hence it ascends almost vertically, but with a slight inclination inwards, beneath the perito- neum, and on the psoas muscle ; until, finally, it crosses under the transverse meso-colon, to end by a junction with the splenic vein (rf, Jig. 279.). In the latter part of this ascent, it is of course unaccompanied by the inferior mesenteric artery : and even below where this vessel is given off from the aorta, the artery and vein diverge so as to be compara- tively distant from each other. Its j'unction with the splenic vein (d,Jig. 279.), is usually about one or two inches from the point where this meets with the superior mesenteric vein. But it occasionally approaches much more closely to the latter vessel, or even joins with it prior to its union with the splenic to form the portal vein. The branches of both these mesenteric veins resemble those of the corresponding arteries in their number and size, and in the remarkable freedom of their anastomosis. And this copious and frequent inosculation, — which coincides with an absence of all valves, — not only holds good of the several primary branches which converge into the portal vein, but also applies in some degree to those smaller ramifications, by which the portal sj^s- tem inosculates with the general venous sys- tem at the two extremities of the alimentary tube. Thus many of the smaller veins at the lower part of the oesophagus communicate with both the azygos and portal veins. While the Branches of the portal vein. a, trunk of the portal vein ; 6, superior mesenteric vein ; c, inferior mesenteric vein ; d, splenic vein, joined by the, e, gastro-epiploic and pyloric veins ;/, pancreatico-duodenal veins ; f the latter growth itself. The cancerous disease of the intestinal canal is often associated with the existence of a limited amount of hypertrophy. For the deposit of scirrhus in the coats of the canal not only thickens and hardens their substance; but, by the annular form it affects, has a special tendency to obstruct the calibre of the tube. Where it does this slowly, and with little disturbance of the general health, the obstruction is often partially compensated by a true conservative hypertrophy of the mus- cular coat behind the diseased part. But, for similar reasons, this hypertrophy is often associated with dilatation : — an alteration which is indeed sometimes carried to an enormous extent ; so that the stomach, for ex- ample, fills almost the whole abdominal cavity. Of the various morbid conditions already alluded to, there is only one which is very liable to be mistaken for cancer ; namely, that fibrous thickening of the gastric and intestinal parietes which is usually termed hypertrophy. This state offers so many points of resemblance to the scirrhcus deposit, that it seems worth while to enumerate the chief points of con- trast between them. Of these we will only pre- mise that, though they generally afford ample materials for a satisfactory decision, they occasionally leave us in great doubt as to the fibrous or scirrhous character of the particular specimen under examination. Comparing these two states in their ordi- nary form, as seen in the stomach, we may sum up their chief differences as follows : — 1. The scirrhus affects the submucous tissue in a greater degree than the hypertrophy, which is more evenly distributed throughout the three coats. 2. The scirrhus often presents a similar irregularity of distribution in the horizontal plane of the gastric coats them- selves, which it thus renders uneven and protuberant ; while the hypertrophy forms what is generally a larger and more uni- form expanse. 3. The appearance of the scirrhus is white, hard, and gristly or carti- laginous ; that of the hypertrophy is yellower, tougher, and more elastic. 4. The mus- cular substance is involved in hypertrophy chiefly by the atrophy or enlargement of its bundles, within their thickened cellular sheaths. But in scirrhus, it undergoes a characteristic metamorphosis; by virtue of which its structure may almost be * said to approach that of colloid cancer. The fibrous septa become the seat of a development of new fibres ; while in their loculi or intervals, the muscular fibres are replaced by a reddish- yellow gelatinous substance, which consists * Marked specimens of this kind are, I believe, sometimes mistaken for the rarer true areolar cancer. of characteristic cancerous cells, in various stages of development. 5. The scirrhus fuses and confounds the various tunics; which, in the hypertrophy, generally remain tolerably distinct. 6. In scirrhus, ulceration is of more frequent occurrence, of earlier access, and of wider extent, than in hypertrophy. 7. In scirrhus, the neighbouring glands and organs generally become at length affected by an enlargement and deposit, which itself par- takes of the cancerous characters. 8. The microscopic characters of the two morbid products are usually decisive; the scirrhus almost always offering the cell-forms charac- teristic of cancerous growth, in some part or other of its mass. Thus, for instance, even where the fibres of the central and cartilaginous substance are so numerous and well-developed as to obscure the cells they involve, the gelatinous matter enclosed within the meshes immediately around this harder mass will generally yield an abundant cell- growth ; or the still softer periphery of the tumour will afford the unmistakable cells of medullary disease. Of the various segments of the digestive canal, the stomach is by far the most frequent seat of cancer. The large intestine stands next to it in liability to this disease, the lia- bility diminishing successively from the rectum through the sigmoid flexure, to the remainder of the colon. In the coecum, however, it seems somewhat increased. The small intestine is very rarely affected, except in acute and ge- neral cancerous cachexia; in which the mucous membrane, and its submucous tissue, are some- times infiltrated with medullary deposit in the situation of the agminate follicles. In the stomach, cancer generally occurs as a scirrhous deposit which surrounds the py- loric extremity of the organ. The cancerous growth is strictly limited towards the duo- denum, by the pyloric valve; but it extends a variable distance along the right side of the organ, generally favouring the lesser curvature. The neighbouring gastric surface is often oc- cupied by small isolated deposits of cancerous matter, which lie beneath the mucous mem- brane. And the healthy muscular coat, as before mentioned, is also frequently hyper- trophied over a large extent of the same locality. The chief peculiarities of the scirrhous mass have been enumerated in speaking of the differential diagnosis between it and hypertrophy of the stomach. Beginning in the submucous tissue, and the subjacent mus- cular coat, it rapidly involves both of these structures in a white cartilaginous-looking mass ; the more opaque and fibrous parts of which often seem to give off bundles of fibres, that pass completely through the muscular coat. The anatomy of these fibrous bundles has already been mentioned. The disease advanc- ing, involves the subserous tissue and the pe- ritoneum, on the one hand; and the mucous membrane on the other. The latter of the two extensions is generally both earlier in E E 3 422 STOMACH AND INTESTINE. date, and more considerable in amount. After the disease has thus fused into one mass the muscular and mucous coats, thedistention and vascular disturbance undergone by the latter gradually effects its disorganization. Its epi- thelium becomes detached; its surface ulce- rates or sloughs ; and more or less haemor- rhage is excited. At this time, if not before, the cancerous process is generally so far mo- dified, as to give rise to the deposit of the medullary instead of the scirrhous variety. The eroded surface of the tumour thus be- comes the site of a bleeding fungous growth ; the haemorrhage from which, more or less altered by the fluids of digestion prior to its being ejected from the stomach, gives rise to the characteristic coffee-coloured vomiting which is almost always present in the latter stages of the disease. The metamorphosis of the cancerous mass is generally followed by sloughing or ulceration, either of which may end in the perforation of the organ. But this event is sometimes prevented by the adhesion of the peritoneal surface of the stomach to neighbouring structures; and is, perhaps, still more frequently staved off by the continuous deposit of new cancerous matter beneath and around the ulcerating mass. The perforation of the gastric parietes may give rise to an abnor- mal communication between the stomach and some neighbouring segment of the canal : — for example, the transverse colon, or some part of the small intestine. Or it may even open on the exterior of the belly ; or penetrate the thoracic cavity. The medullary form of cancer, which is not unfrequently seen as a secondary deposit at the surface and margins of the scirrhous mass, sometimes occurs independently, as a con- tinuous or discrete deposit in the submucous areolar tissue. It offers its ordinary charac- teristic structure and appearance. The areolar form is also more frequently secondary than primary. It is by no means uncommon to find the hard scirrhous texture of the centre of the cancerous pylorus merge into a fibrous network as it approaches the inner surface of the organ; — a network the large meshes of which are filled with a ge- latinous mass. The fibres which constitute these meshes are generally long, pale, and ex- tremely delicate ; and their narrow outline is here and there bulged by persistent develop- mental cells. The gelatinous mass which they enclose consists of cells, which are often large and compound ; sometimes caudate, or pigmentary. It is possible that this structure is to some extent produced by a true me- tamorphosis of the previous scirrhus : its fibres being multiplied, at the same time that they are enlarged and distended by the deposit, between and amongst them, of a soft mass of cells. In some instances we find evident traces of a development of new fibres, which gradually break up the primitive loculi into secondary cells. The most superficial or internal of these loculi project from the mucous surface into the ca- vity of the stomach; where they often become the seat of a medullary or fungous growth, which undergoes ulceration and haemor- rhage. Stricture of the intestine. — The most fre- quent cancerous affection of the large intes- tine is a scirrhous deposit, which more or less encircles the tube, The extent to which it passes round the circumference of the canal is determined chiefly by its primary or secondary nature. In the former case, it is a complete circle. In the latter case, it generally forms but part of a circle ; and occupies that side of the intestine, which is nearest to the gland or other neighbouring texture, from which the disease may have been derived. In either kind of scirrhous stricture, the deposit may subsequently extend, for a va- riable distance, in the direction of the length of the canal. But so long as it remains li- mited to a simple annular mass of gristly scirrhus occupying the submucous tissue, its chief effect is that of narrowing the canal. The influence of this narrowing on the neighbouring segments of the bowel is at first merely the mechanical obstruction which it offers to the transit of the intestinal contents. Where this obstruction amounts to a complete occlusion, it is speedily fatal : the intestine above the stricture becoming enormously dis- tended by its contents; and undergoing in- flammation, gangrene, or even rupture, as the result of this distention. A slower process of constriction, or a less complete obstruction, generally give rise to a combination of a si- milar dilatation, with a variable degree of hypertrophy; the latter change being often carried to such an extent as greatly to increase the thickness of all the coats of the bowel, and especially of the muscular tunic. The obstruction is often increased by the way in which the diseased part of the in- testine becomes abnormally united with neigh- bouring viscera or walls of the belly, In the secondary form of scirrhus, the mass is of course attached and fixed, almost at the very commencement of the process of deposit. But in the primary form, it may remain free until a comparatively late period of the disorder; when the weight of the tumour often causes the bowel to gravitate into a more or less unnatural position. In either case, its oc- currence often alters the course of the canal, by bending it at an acute angle opposite to the adherent part. The bowel is thus placed at a still further disadvantage for the trans- mission of its contents. The subsequent progress of the disease requires little notice. The growth of a me- dullary fungus, or the deposit of a colloid or areolar mass upon the surface of the ulce- rated stricture, may of course increase the obstruction which the latter produces. Or, conversely, its sloughing or ulceration may restore the permeability of a previously al- most occluded canal. Finally, the exten- sion of the disease upwards, into the dilated segment of intestine above the stricture, may SYMPATHETIC NERVE. 423 convert this part into a large receptacle, which is bounded by thick and solid cancerous walls. Where the lower outlet of this cavity remains patulous, life is sometimes preserved under such an unfavourable condition during a con- siderable period of time. (The NERVES of the Stomach and Intes- tine are described in the article " SYMPA- THETIC NERVE.") ( William Brinton.} SYMPATHETIC NERVE.— The term sympathetic nerve is applied to denote a series of ganglia arranged along each side of the spinal column, connected by intermediate bands of nerve fibres, so as to present the form of two gangliated cords. These extend from the upper part of the cervical region to the lower extremity of the sacrum, where the cords of opposite sides are united in a single ganglion or plexus situated in front of the coccyx. The ganglia in each cord correspond in number to the vertebrae, except in the cer- vical region, where only three ganglia com- monly exist. The gangliated cord of either side forms communications with all the cor- responding spinal nerves along its course. Branches are also sent upwards from the superior cervical ganglion into the head which communicate with nearly all the cranial nerves, and with which several small ganglia, arranged in different parts of the skull, are connected. From the gangliated cords branches also pass inwards for the supply of the bloodvessels, as well as to almost all the different viscera in the body. These branches are remarkable for their tendency to form plexuses, from which subsidiary branches are sent off to the various viscera in their vicinity. Connected with these plexuses, as well as with the branches which pass off from them, are nu- merous ganglia of different sizes. This nerve has been variously named by authors. The older anatomists described it under the name of the great intercostal nerve. From the fact of its being chiefly dis- tributed to the viscera belonging to the cir- culatory, digestive and generative systems, it was termed by Chaussier the trisplanchnic nerve ; and under the supposition that it alone influences the organic processes, it was termed by Bichat the nervous system of organic life. The name sym pathetic, or great sympathetic, was given it by Winslow, from its being be- lieved to be the channel through which are effected the different sympathies sometimes found to exist between distant organs when in a morbid condition. For the sake of description the sympa- thetic may be regarded as consisting of two portions ; the one corresponding to the right and left gangliated cords situated on each side of the vertebral column, the other to the dif- ferent plexuses occurring on the branches which are sent inwards for the supply of the viscera and bloodvessels. It is commonly further subdivided into a cervical, thoracic, lumbar, and sacral portion. In the following account of its descriptive anatomy it is pro- posed to describe, 1st, the gangliated cord of the sympathetic, and 2nd the different plexuses formed by its branches in the several regions of the body already specified. I. Cervical Portion of the Gangliated Cord. — The cervical portion of each gangliated cord lies in front of the vertebral column, separated from it by the rectus capitis anticus major and longus colli muscles. It is situated behind the internal and common carotid arteries, the internal jugular vein, and pneumogastric nerve. It presents commonly but three ganglia, named, according to their situation, superior, middle, and inferior. 1. The superior cervical ganglion is situated at the upper and lateral part of the neck, in front of the transverse processes of the second and third cervical vertebrae, upon the rectus capitis anticus major muscle, behind and to the inner side of the internal carotid artery and the pneumogastric and glossopharyngeal nerves, with the sheath of which it is more or less intimately connected by some cellular tissue. It is the largest of the ganglia in the sympathetic cord; it varies considerably in its form and size. In general it presents an elongated oval, or spindle-shape, and mea- sures from 4 to 8 lines in length, 2 to 3 in breadth, and about 1^ in thickness. Accord- ing to Flourens it is generally bifurcated at its lower extremity, and frequently presents a constriction about its middle which appears to divide it into an upper and lower portion. The branches connected with this ganglion are the following : (a) Communicating branches pass between it and the three or four upper cervical nerves. They vary in number, and are connected with the posterior aspect of the ganglion. It also forms communications with the pneumo- gastric, hypoglossal, and glossopharyngeal nerves. The branch of communication with the ninth, or hypoglossal nerve, consisting of one or two delicate filaments, joins it near the base of the skull. This communication is regarded by Scemmering, Cloquet, Hirzel and others as very rarely existing. In twelve bo- dies examined by the latter, he found it pre- sent only twice. Arnold, Longet and others regard the communication as constant. The communication with the pneumogastric nerve is twofold. One small branch passes betw een the superior cervical ganglion itself and the ganglion on the trunk of the vagus ; another branch, also of small size, passes upwards from the ascending branch of the superior cervical ganglion, and divides at the base of the skull into two filaments, one of which becomes con- nected with the ganglion of the root of the pneumogastric, while the other terminates in the petrosal ganglion of the glossopharyngeal nerve. (6) Ascending or Carotid Branch. — This branch may be regarded as a prolongation up- wards of the sympathetic cord. It is soft, and presents a more or less greyish -red aspect. On approaching the inferior orifice of the E E 4 424 SYMPATHETIC NERVE. carotid canal in the temporal bone, it com- monly divides into two branches which pass along the canal with the internal carotid artery, the one being situated rather to the inner, the other to the outer side of the vessel ; they form numerous intercommunica- tions with each other, giving rise to what is termed the internal carotid plexus. (c) Pharyngeal Branches. — These, from three to six in number, leave the upper and inner margin of the ganglion, pass inwards and downwards, and unite with the pharyngeal branches of the glossopharyngeal and vagus nerves to form the pharyngeal plexus. (rf) External lateral Branches. — These vary in number ; sometimes there are only two present ; at other times as many as six or eight. They have a greyish-red colour, and from the softness of their texture were termed by Scarpa nervi molles, from their being chiefly distributed to the blood vessels, they were named by Scemmering vascular branches. They arise from the front of the ganglion, and pass downwards along the internal carotid artery to the point of division of the common carotid, where they give rise to the external carotid plexus. Some filaments also unite with the superior laryngeal nerve. (e) Superior or long cardiac Nerve, named also the superficial cardiac branch, varies in thickness, and is sometimes absent. It arises from the anterior and lower portion of the superior cervical ganglion, sometimes from the intermediate cord between that and the middle cervical ganglion, and sometimes it derives filaments from both sources. It runs downwards upon the longus colli muscle and to the inner side of the sympathetic cord, and passes behind or in front of the inferior thyroid artery. In its course through the neck it forms communications with the ex- ternal laryngeal and descendens noni nerves ; it also communicates with the vagus and re- current laryngeal nerves, and sometimes with the phrenic. Not unfrequently it is joined by the cardiac branches, which leave the middle and inferior cervical ganglion. It passes into the chest in front of or behind the subclavian artery, and along the arteria innominata, to terminate in the cardiac plexus. The nerve of the left side, after entering the chest, runs along the left carotid artery to the arch of the aorta, passing sometimes in front and sometimes behind that vessel. (/) Communicating cord between the su- perior and middle cervical Ganglia. — The con- necting cord between the superior and middle cervical ganglia is commonly single, but occa- sionally consists of two distinct portions. It passes from the inferior extremity of the superior cervical ganglion, which sometimes seems to be prolonged downwards into it, along the surface of the rectus capitis anticus major muscle, behind the carotid artery, and rather to the inner side of the pneumogastric nerve, as far as the inferior thyroid artery. Before sinking into the middle cervical gan- glion it sometimes divides into two portions, one of which passes in front, the other behind the vessel just mentioned. The communi- cating branches with the third, fourth and fifth cervical nerves frequently join it instead of passing to the cervical ganglia. There is also, according to L. F. Meckel, sometimes formed upon it, above the inferior thyroid artery, a small ganglion termed by some the superior thyroid ganglion, and by others the middle cervical ganglion. 2. Middle cervical ganglion, smaller than the superior ganglia of the same name, pre- sents an irregularly oval or triangular shape, and is situated on or near the inferior thyroid artery. Communicating branches pass be- tween it and the fifth and sixth cervical nerves; it is also sometimes connected by filaments of communication with the vagus and phrenic nerves. From the inner side of the ganglion several delicate greyish filaments pass off which surround the inferior thyroid artery forming a plexus, which is termed the inferior thyroid plexus. These branches communicate with the recurrent and internal laryngeal nerves, as well as with the upper cardiac nerve. The middle cervical ganglion also gives a branch which is sent to the cardiac plexus. This branch, termed the middle or deep cardiac nerve, arises from the ganglion by from two to four roots which unite into a single or double stem. It passes into the chest in front of the subclavian artery, but sometimes behind that vessel, and runs along the arteria innominata to the deep cardiac plexus. On the left side it enters the chest be- tween the left carotid and subclavian arteries. 3. Inferior cervical ganglion, varies in its size and form, which, in general, is more or less semilunar ; its convexity being directed downwards, its concave margin upwards. It is situated between the transverse process of the seventh cervical vertebra and the neck of the first rib, behind the subclavian artery, and behind and to the outer side of the root of the vertebral artery. («) Branches of com- munication pass between the ganglion and the seventh and eighth cervical nerves, as well as the first intercostal nerve. It also sometimes communicates with the phrenic nerve and recurrent Jaryniiaeal. (b) From the ganglion proceed several fine twigs, which surround the subclavian artery as well as its branches, forming small plexuses about them. One of these accompanies the vertebral ar- teries ; according to some it passes up along with the artery into the cranium, subdividing into as many secondary plexuses as there are branches of the artery. Blandin states that he has followed the branches of the nerve along the basilar artery, upon the posterior cerebral and cerebellar arteries. Whilst situ- ated within the canal in the transverse pro- cesses of the cervical vertebra it communi- cates with several of the cervical nerves. According to M. De Blainville several gan- glia occur on this branch, equal in number to the cervical vertebras, and hence he regards the vertebral branch as the continuation up- SYMPATHETIC NERVE. 425 wards of the sympathetic cord. According to Bourgery*, the common sympathetic trunk may be regarded as dividing at the inferior cervical ganglion into an anterior and a pos- terior portion; the former, corresponding to the continuation of the cord in the neck, he terms the carotid track, the latter, correspond- ing to the vertebral branch, he terms the pos- terior or vertebral track. He describes it as arising from the plexus formed around the subclavian artery : it is quite visible to the naked eye at its origin, but higher up its filaments become microscopic in point of size: the vertebral branches, or tracks of opposite sides, unite together in the groove lodging the basilar artery, and communica- tions are also formed between them and the anterior, or carotid track, by means of fila- ments which pass backwards with the pos- terior communicating arteries. The vertebro- basilar nervous apparatus, as it is termed by him, supplies nerves to the vessels, which ramify on the cerebellum and posterior lobe of the cerebrum. (c) Inferior or small Cardiac Nerve. — The inferior cardiac arises by one or two roots, passes inwards behind the subclavian artery, and terminates in the deep cardiac plexus. It forms communications with the middle car- diac nerve, as also with the cardiac branch of the recurrent laryngeal. Frequently, espe- cially on the left side, the lower cardiac branch becomes united with the middle car- diac, giving rise to what has been termed the Nervus cardiacus crassus. The communi- cating branch between the lower cervical and first thoracic ganglion is very short, some- times wanting, the two ganglia running into one another. II. Thoracic portion of the Gangliated Cord. — The thoracic portion of the gangliated cord of the sympathetic lies on each side of the spinal column, in front of the transverse pro- cesses of the vertebrae and heads of the ribs, and beneath the pleura. It is continuous above with the cervical portion, and below it passes into the abdomen, between the pil- lars of the diaphragm and superior extremity of the psoas muscle, outside the splanchnic nerves, becoming continuous with the lumbar portion of the sympathetic cord. The num- ber of the ganglia varies : they are commonly eleven, rarely twelve, on each side. They are, in general, situated between the heads of the ribs in front of the transverse processes of the vertebrae, and present commonly a more or less triangular form. The cord connecting the ganglia of either side runs in front of the heads of the ribs, and is ge- nerally single, though sometimes it is double. The branches connected with the thoracic ganglia are the following : — («) Communicating branches pass between each of the ganglia and the corresponding * Memoire snr 1'extremite c^phalique du grand sympathetique dans 1'bomme et les animaux mam- miferes. par M. I. M. Bourgery. Comptes Rendus, vol. xx. intercostal nerve : these are commonly double, sometimes three, short, and pretty strong. (b) Branches of small size pass from the ganglia to the descending aorta, forming a plexus around it; others pass to the pul- monary and cesophageal plexuses ; branches are also described by Krause as passing be- tween the ganglia of opposite sides in front of the bodies of the vertebrae. (c) The chief branches leaving the thoracic ganglia are the greater and smaller splanchnic nerves. These are situated to the inner side of the main cord of the sympathetic, and also more anteriorly, upon the lateral and anterior surface of the bodies of the vertebrae. They are formed of branches derived from the six lower thoracic ganglia, and pass through the diaphragm into the abdomen. The greater splanchnic nerve derives its roots commonly from the inner part of the sixth, seventh, eighth, and ninth, thoracic ganglia ; it often also receives a branch from the fifth, and, according to Dr. Beck, from the different ganglia as high up as the first. It passes obliquely downwards and slightly inwards upon the sides of the vertebral column, in front of the intercostal vessels, and covered by the pleura. It enters the cavity of the abdomen by perforating the pillars be- tween the middle and internal crura of dia- phragm, rarely through the aortic opening, and terminates in the semilunar ganglion of the cceliac plexus. The smaller splanchnic nerve, which is sometimes double, springs from the tenth and eleventh thoracic ganglia : following the same course as the greater splanchnic nerve, it is directed obliquely downwards and inwards upon the body of the twelfth dorsal vertebra, passes through the diaphragm between the greater splanchnic nerve and the communicating cord, which unites the last thoracic to the first lumbar ganglion, or pierces the middle cms of the diaphragm. It terminates in the cceliac and renal plexuses ; the branch to the latter being generally stronger than that to the former. (d) The communicating cord between the last thoracic ganglion and first lumbar enters the cavity of the abdomen between the middle and external crura of the dia- phragm, or penetrates the latter. III. Lumbar portion of the Gangliated Cord. — The lumbar portion of the sympathetic cord generally contains five ganglia, some- times only three or four, and is situated upon the lateral and anterior aspect of the bodies of the lumbar vertebrae, in front of the psoas muscle, behind and to the left of the aorta on the left side, and behind and to the right of the vena cava on the right. The branches connected with the lumbar ganglia are : — (a) Branches of communication with the lumbar nerves: these are commonly two in number for each ; they are longer than those in the thoracic region, and pass between the heads of the psoas muscle. — (6) Branches also pass off from the ganglia to the aortic, spermatic, renal and superior hypogastric plexuses. — (V) 426 SYMPATHETIC NERVE. Krause describes branches as passing across the bodies of the vertebrae, forming a com- munication between the ganglia of opposite sides. IV. Sacral portion of the Gangliated Cord. — The sacral portion of the sympathetic cord is situated towards the inner side of the sacral foramina. The ganglia are commonly four in number, are smaller than those in the lumbar region, and decrease in size from above downwards : the cords of opposite sides con- verge as they pass to the lower extremity of the sacrum, and unite together in front of the coccyx, there being frequently present at their point of union a small ganglion, from which one or two filaments of communica- tion pass to the fifth sacral and coccygeal nerves. The branches connected with the sacral ganglia are communicating branches with the spinal nerves, commonly two in number for each. Several delicate filaments are also sent to the inferior hypogastric plexus. PLEXUSES OF THE SYMPATHETIC. A. In the Head. — The chief plexuses of the sympathetic which exist in the head are the internal carotid plexus, cavernous, and external carotid. There are also present in different parts of the head several ganglia: the principal of these are the ciliary ganglion, spheno-palatine, otic, and submaxillary. These ganglia have been already described in this work in the articles on the different nerves with whose branches they are connected. 1. Internal Carotid Plexus. — The internal carotid plexus is formed by the ascending branches of the superior cervical ganglion, and surrounds the internal carotid artery during its passage through the carotid canal. The as- cending branch of the superior cervical gan- glion, as was already stated, divides into two portions, one of which passes along the outer and anterior aspect of the artery, while the other lies on the inner and posterior aspect of the same vessel. The external portion is chiefly concerned in the formation of the carotid plexrs, the inner in forming the cavernous plexus. The carotid plexus is thus situated chiefly on the outer side of the artery between its second and third bends. The branches connected with the plexus are, — («) Two or three filaments of communica- tion with the sixth pair of nerves ; they join the nerve as it passes along the cavernous sinus. One of these, stronger than the others, was formerly regarded as one of the roots of the sympathetic nerve. One filament is said sometimes to run only a short distance with the sixth nerve, when it leaves it and passes to the ciliary ganglion, or to the spheno-pala- tine. (6) Great or deep Petrosal Nerve. — This branch, commonly termed the deep branch of the Viclian nerve, may be regarded as passing from the fifth pair to the sympathetic, or vice versa. Regarding it as the latter, it may be described as passing out by the superior ori- fice of the carotid canal, traversing the car- tilaginous substance which occupies the an- terior lacerated foramen to reach the pterygoid canal, where it becomes associated with the cranial division of the Vidian, along with which it traverses the canal from behind for- wards, and terminates in the ganglion of Meckel. In the interior of the pterygoid canal, the two nerves are merely placed* side by side with each other, and after leaving the canal are connected separately with the gan- glion. The greater or deep petrosal nerve was formerly regarded as the second of the two roots by which the sympathetic was sup- posed to begin. (c) From three to five delicate short branches pass through the outer wall of the cavernous sinus and join the Gasserian ganglion on its inner surface. One or two of these have been described as passing backwards to the ten- torium cerebelli, and have been traced by Arnold to the walls of the transverse sinus. The filaments to the Gasserian ganglion are sometimes supplied by the cavernous plexus. 2. Cavernous Plexus. — This name is applied to the plexus formed around the internal carotid artery as it lies in the cavernous sinus; it is situated rather towards the inner surface of the vessel, at the point where it makes its highest turn. The branches which leave the cavernous plexus are the following : — (a) Filaments which join the third nerve ; they are two or three in number, and become united with the nerve before its entrance into the orbit. Hirzel regards the communication as rare, having found it only in ten bodies ; in some cases he found that the supposed nerve filaments con- sisted merely of cellular tissue. Bock, Longet, and others regard it as constant. (6) Branches of communication to the fourth nerve ; they are either derived from the cavernous plexus or from the carotid, and join the nerve as it lies in the cavernous sinus. ( loped on the course of a nerve-fibre arising in the brain and spinal cord. On the contrary, it would appear that several of the cells be- longing to this variety must also be regarded as giving origin to nerve-fibres in the same manner as the unipolar cell. Thus Bidder has seen bipolar cells, the nerve-tubes con- nected with which did not run in opposite directions, one towards the brain and spinal cord, the other towards the periphery, but both ran in the latter direction (fig. 291.) : so also Stannius, as mentioned by Kolliker, has Fis. 291. Bipolar ganglionic corpuscle, Loth nerve-fibres con- nected with which run peripherically. From the spinal ganglion of a Fish. (After Bidder.} seen in the ciliary ganglion of Trigla, a bi- polar cell, both nerve-fibres of which were directed peripherically. The same observer has also seen ganglionic corpuscles in the fish which gave origin to or had three nerve-tubes connected with them. That most of the bipolar cells are, how- ever, as Robin maintains, organs developed on nerve-fibres of cerebro-spinal origin, in their course towards the periphery, there is no * Engel in Zeitschrift der Wien. Aerzte, iv. p. 307., as quoted in Kolliker's Mikroskopische Anatomic, p. 532. reason to doubt; and moreover that several of these may occur in the course of a single fibre between its central and peripherical ter- mination is also shown by the observations of Stannius on [the fish, and by Valentin on the frog. Wagner has also observed two ganglion-corpuscles occurring in the course of a single nerve-fibre, at short distances from one another. Robin* divides the ganglionic corpuscles into two distinct classes, a larger and a smaller : the larger he finds always occur on broad nerve- fibres, or fibres of animal life, while the smaller are always connected with nerve-fibres be- longing to the finer variety, or fibres of or- ganic life ; and in this way, according to him, we have a good mark by which to distinguish the animal from the organic nerve-fibres. In the ray, according to Robin, the larger variety of corpuscles measure 0'095 to 0*150 mm. in diameter, are spherical, and often flat at both poles; the smaller measures 0*080 to 0*115 mm. in length, and 0*050 to 0*070 mm. in breadth, and are commonly oval. , In the larger cells there is a layer of clear round bodies, without nuclei; in the smaller gangli- onic corpuscles the outer membrane is finer, and each of the cells, on their inner sur- face, . is provided with a central dark nu- cleus. Bidder f also agrees with Robin in separating the ganglionic corpuscles into two groups. In the pike the one set measure O'O^"', while the other set do not measure more than 0*0 18//r: the former chiefly occur in the ganglia of the cerebro-spinal nerves, the latter in the ganglia of the sympathetic ; the former are always connected with broad fibres, the latter with fibres belonging to the fine variety. The views of Robin and Bidder are opposed by Kolliker, Valentin, and ap- parently also by Wagner. The latter admits that in general the ganglionic corpuscles are smaller than those occurring in the spinal ganglia, and that the smaller corpuscles have, as Robin observes, an oval shape, while the larger are more or less spherical : there are, however, according to him, cases where broad nerve-fibres are seen passing off from small cells, and where the large cells are connected with small or narrow fibres. Sometimes, in- deed, the ganglionic corpuscle has a narrow tube on one side, and a broad one on the op- posite side (see fig. 290.); and sometimes the broad, sometimes the narrow, runs peripheri- cally. Stannius has, as mentioned by Kolliker, observed in Petromyzon cells present, of the fibres connected with which the one was six times broader than the other. Although, how- ever, there does not appear to be a distinct de- marcation between the ganglionic corpuscles belonging to the two sizes, there can be little doubt that the cells occurring in the sympa- thetic ganglia are generally smaller than those occurring on the cerebro-spinal nerves, both in the fish and also in the higher animals. The larger cells in the spinal ganglia of the * Annales des Sciences Xaturelles, torn, septieme, 1847, p. 282. ; also Canslatt's Jahresbericbt, 1847. f See Causlatt's Jahresbericht, 1847. SYMPATHETIC NERVE. 443 ray appear, as Robin states, to be (in general at least) connected with broad fibres, while the smaller cells are connected with narrow fibres : this, however, does not appear to be invariably the case. In the sympathetic gan- glia there are sometimes seen" connected with narrow fibres cells as large as some of those in the spinal ganglia, which are connected with broad fibres. Moreover, as already stated, there appear to be transitional sizes between the larger and smaller variety of cor- puscles. Kolliker also calls attention to the fact that small ganglionic corpuscles occur in other parts than in the sympathetic, as for example those in the brain and spinal cord. It would seem, then, that just as the finer variety of tubular nerve-fibres cannot be re- garded as characteristic of the sympathetic system, so also the smaller variety of gan- glionic corpuscles cannot be regarded as pe- culiar to it either. It has been already stated, that the nerve- fibres which compose the posterior root of the spinal nerves in the ray, &c., have all, according to Wagner, ganglionic corpuscles developed upon them. He concludes from this, that all sensory fibres are so constituted, and that we have thus a good mark by which a sensory nerve-fibre may be distinguished from one possessed of motor properties. To this view, however, it is objected by Kolliker, that in the higher animals at least, so far is it from being the case, that all the fibres in the posterior roots of the spinal nerves are provided with these structures, that not one of the fibres proceeding from the spinal cord enters the ganglion at all, the nerve fibres connected with the ganglion be- ing fibres which arise in it and run peripheri- cally, not one of them passing in the opposite direction towards the spinal cord. In ex- amining the spinal ganglia of the mouse, after addition, as Kolliker directs, of dilute solu- tion of soda, I have often had no difficulty in observing, that a great portion at least of the fibres in the posterior root run past the ganglion without forming any connection with its corpuscles, and, moreover, that the fibres of the ganglion appear to be directed periphe- rically, as he states.* * A paper on multipolar ganglion-cells has been published by Remak in the Monatsbericht der Konigl. Preuss. Akademie der Wissenschaften zu Berlin flir Januar., 1854, translated also in the Edinburgh Monthly Medical Journal for April, 1854. He mentions that it was first made known by Stilling's discovery of the so-called nerve-nuclei in the pons Yarolii of man and of the mammalia, that the multipolar ganglion -cells discovered by Purkinje, MUller, and himself (1837), in the cen- tral organs of the vertebrata are connected with motor nerve -fibres. It has also been ascertained by Wagner (1847), that each of the large multipolar ganglion-cells of the electric lobes in the torpedo becomes continuous by means of a process with the axis cylinder of a fibre of the electric roots of the n. vagus and trigeminus. The other branched pro- cesses of these cells, distinguished by their granular or striated appearance, serve the purpose, according to Wagner, of connecting the cells with each other. Remak could not, however, in an examination of the Torpedo marmorata find such connections. On Connection bettueen the Sympathetic and Cerebro-spinal Systems. — By the older ana- treating the fresh brain with a solution of sublimate or of double chromate of potash, the electric lobes are easily separated into their constituents. All the ganglion-cells are multipolar, surrounded by delicate nucleate sheaths, and occupy the meshes of a network formed of wide vessels with thick walls. The processes destined for the formation of the electric roots of the vagus and trigeminus collect themselves at the base of the cerebral lobes into strong bundles visible to the naked eye. The re- maining branched processes, becoming surrounded by a thin medullary sheath, form nerve-tubes with dark borders, which pass into the medulla oblongata. A connection of the cells with sensory fibres has not as yet been demonstrated ; the sensory roots of the vagus and trigeminus do not pass into the electric lobes ; rather those of the former pass into the medulla oblongata, those of the latter into a gray appendix of the cerebellum (feuillet restiforme of Lerres and Lavi), which in its structure, par- ticularly in the size and form of its multipolar ganglion-cells, agrees with the cerebellum, but not with the electric lobes. He mentions that he has in his possession trans- verse and longitudinal sections from the spinal cords of man and of the ox, prepared by Stilling, in which, as mentioned by the latter, the passage of nerve-fibres belonging "to the motory roots into multipolar ganglion -cells of the anterior gray co- lumn is observed. He finds also in the transverse sections small bands of broad nerve-fibres with dark borders, which seem to unite the anterior and posterior roots. From the place of entrance of the anterior roots into the anterior gray columns, or commencing at the onter circumference of the latter, they run as far as the posterior surface of the sub- stantia gelatinosa, where the posterior roots enter the latter. Here they are connected with the gan- glion-cells, which send one of their processes to the sensory roots, while the chief mass of the latter radiates in broad thick bands through the gela- tinous substance into the posterior gray columns as far as the seat of the large multipolar ganglion- cells. These circular bands of fibres may be pre- sumed to indicate one of the paths on which in decapitated animals the stimuli applied to sensory nerves gives rise to reflex movements. It is re- markable in this respect, that the long axis of the largest ganglion-cells has the same direction as the long axis of the spinal cord, and that besides the lateral processes by whose means they are con- nected with the fibres of the roots of the nerves, they send out branched processes at both poles tow'ards the cephalic and caudal extremities of the spinal cord. In the spinal ganglia the multipolar cells dis- covered by Remak in 1837 in the ganglia are not found. They consist rather, as he observed, in fresh plagiostomes, without exception of the bipolar cells simultaneously described by Robin and Wag- ner (1846). These constitute, as shown by Leydig in Chimaera monstrosa, nucleated swellings of the axis cylinder, and are surrounded by a sheath con- sisting of an epithelial layer, and of a firm mem- brane, which is continuous with the sheath of the nerve-tube. Bipolar cells may also be obtained from the spinal ganglia of man and of the mam- malia. They frequently appear unipolar when the two processes leave the cell close to one another. More frequently, however, as Kolliker observes, are cells seen with a single process ; this probably di- vides after a short course into two fibres. He finds at least in the spinal ganglia of the mammalia (ox), not unfrequently, divisions of nerve-tubes with dark borders, which he misses in the plagiostomes. Of the ganglia, it is exclusively the sympathetic which are made up of multipolar ganglion-cells. The sheath of the latter consists, as in the spinal ganglia, of a delicate layer of cells and of a strong 444 SYMPATHETIC NERVE. tomists, the sympathetic was described as a nerves, reinforced by fibres sent to it from continuation of the fifth and sixth cranial the different-cerebro spinal nerves along its membrane. The number of processes varies between three and twelve ; by speedily branching they may be increased threefold and upwards. The number is regulated by the number of nerves connected with the ganglion ; and hence it is smaller in the main cord than in the solar plexus. The processes have in general the optical and chemical properties of the axis cylinder of the nerve-fibres. In the solar plexus there are found, however, ganglion cells whose processes are distinguished from one another in a similar manner to those of the ganglion cells in the electric lobes of the torpedo. Besides the multipolar ganglion cells, bipolar cells are also ob- served in the plagiostomata and mammalia. They differ from those of the spinal ganglia, however, in this, that both processes branch, thus coming to agree essentially with the multipolar cells. The same holds of the unipolar cells which, in the ani- mals mentioned, are sometimes found along with multipolar, and which in the batrachia and osseous fishes, as well as in the head of the mammalia, almost alone constitute the sympathetic ganglia. In transverse or longitudinal sections of the thoracic or abdominal sympathetic ganglia in the mammal or plagiostome, the simple (generally very broad) processes of such a unipolar cell are seen after a short course to divide into numerous fibres, which pass off from one another in different directions. That all the processes take a peripherical course cannot, according to Remak, be demonstrated, and is, from what follows, improbable. He has ascertained, namely, that in the mam- malia the multipolar ganglion-cells of the ganglia in the main cord of the sympathetic in the abdomen and thorax become continuous by means of their processes with the axis cylinder of nerve-fibres with dark borders, of such, too, as pass from the spinal ganglia into the ganglia of the main cord. In man and in the mammal, each ganglion in the main cord is , connected, by at least two branches, with spinal nerves. The under branch (ramus com- municans sympathicus s. revehens) is, according to his observations, gray, contains very fine (the fibres of Bidder and Volkmann) nerve-fibres, and very many ganglion-fibres: it joins a spinal nerve for peripherical distribution after it has at its place of entrance, sometimes close to the spinal ganglion, formed another ganglion consisting of multipolar cells. The upper branch (ramus communicans spinalis, s. advehens) is white : it contains the fibres which, according to Wiitzer, &c., may be followed to both roots of the spinal nerves. Remak has as yet succeeded in seeing fibres of this branch enter merely into the anterior root ; the remainder, gene- rally the smaller number, are lost in the spinal ganglion. The sensory fibres destined for the sym- pathetic nerve must, therefore, as it appears, be- come connected with cells of the spinal ganglia before they pass into the main cord of the sympa- thetic. The fibres of this spinal communicating branch either pass directly into the ganglia of the main cord, or they form in part separate white bundles, which apply themselves to the cord, and are lost in the next ganglion behind. Since, now, as transverse sections of the glangia in the main cord show, all entering spinal fibres become con- nected one after another with multipolar glanglion- cells, it follows that if the anterior roots of the spinal nerves contain merely motor fibres, the posterior merely sensory, the multipolar cells in the ganglia of the main cord are found as well in the course of sensory as of motory nerve-fibres. From these cells there pass off in the peripherical direction both broad nerve-fibres with dark borders, and fine fibres (fibres of Bidder and Volkmann), likewise others in which no dark borders can be observed. All these peripherical fibres may be named sympathetic, in opposition to the spinal fibres with which they are connected by means of the multipolar ganglion-cells. There are no grounds for the assumption that (human) sympathetic fibres exist which do not stand in connection with spinal fibres, and consequently not in connection with the great central organs of the nervous system. So also in the nerves passing off from the sympathetic ganglia to organs no spinal fibres have as yet been demonstrated in whose course no sympathetic gan- glion-cells are found. By the above results, it is merely established that in the sympathetic ganglia the angles of branching, or points where sensory and motor fibres divide, contain ganglion-cells. The ganglia are not, however, thereby established to have the function of central organs, so far as we make them depend- ant on the conflux of sensory and motor fibres, and so long as there is no ground for supposing that among the peripherical fibres passing from a sen- sory or motor sympathetic ganglion-cell, as well sensory as motor fibres are found. Ganglion-cells have been observed by Leydig in the angles of branching of sensory fibres in CarinariaMediterranea. In the angles of branching of motor fibres gan- glion-cells are only known in the great central organs. This of itself gives ground for the ques- tion, whether the sympathetic ganglia have the function of central organs ; that is, whether in them there are distinct sensory and distinct motor cells, or whether each multipolar cell serves as a medium of connection between sensory and motor fibres. On the spinal communicating branches, the question has not hitherto been determined, because they are too long, and a trustworthy microscopic distinction between the two kinds of fibres is wanting. On the other hand, other obser- vations favour the view that the multipolar cells are connected both with motor and sensory fibres. In ganglion-cells whose long axis is the same as the long axis of the ganglion, there are frequently seen two fibres entering at one pole and two pass- ing off from the other. If all four fibres were of the same kind, the cell would then form an anas- tomosis between fibres of the same kind, as has only once hitherto been observed by Leydig, as a variety of the bipolar cells in the Casserian ganglion of Chimera monstrosa. If, moreover, in a small multipolar ganglion taken from the solar plexus of a mammal (ox), the number and direction of the nerves passing to and from it be compared with the number and the direction of the processes of the cells, as seen on a transverse or longitudinal section of the ganglion, the fullest correspondence is found to exist between them ; that is, in such a multipolar ganglion each ganglion-cell is connected with nerve-fibres of all the nerves which are connected with the ganglion. That in these cases, each of the nerves entering or leaving the ganglion con- tains only sensory or only motor fibres is, however, improbable for this reason, that in other multipolar sympathetic ganglia, — for example, the ciliary, otic, and spheno-palatine, — we know that the enter- ing nerves contain sensory as well as motor fibres. If the sympathetic ganglion -cells serve as con- necting media between sensory and motor fibres, then the impressions made upon sympathetic sen- sory fibres may be transferred by these ganglion- cells to sympathetic motory ; through the medium of the spinal sensory communicating fibres they will also be enabled to act upon the great central organs (brain and spinal cord), and thence through the spinal motory upon the sympathetic ganglion- cells and their motor processes. Besides the sym- pathetic sensory and sympathetic motory fibres, the assumption of a third set of sympathetic fibres, serving immediately for nutrition, is not required by any fact in physiology, since it is possible to ex- plain the dependence of nutrition upon the nerves by the action of the latter upon the contractile walls of the blood-vessels. SYMPATHETIC NERVE. 4-io course. The communicating branch between the carotid plexus and the sixth nerve, and the deep or carotid branch of the vidian, were regarded as the roots by which the nerve commenced, while the different branches passing between it and the other cerebral and spinal nerves, were believed also to be entirely composed of fibres sent by the latter to the sympathetic. According to Bichat, the sympathetic is an independent system of nerves ; the cords which pass between it and the cerebral and spinal nerves are not entirely composed of fibres sent to the sympathetic, but are partly branches transmitted by it to these nerves. The observations of Petit and Fontana* had already shown that the communication be- tween the sixth nerve and the sympathetic did not consist of fibres sent by the former to the latter, inasmuch as the sixth nerve was found to be thicker beyond the point of junction with the filament than before. In 1827 Retziusf showed that in the tri- facial nerve in the horse there was present a gray fasciculus of fibres distinct from the white, and which seemed to take its origin in the ganglion. Somewhat similar observations were made by Varrentrap and Miiller on the branches of the trigeminus, and by Giltay on the glosso-pharyngeal, vagus, and superior spinal nerves of the fish, &c. It was after- wards noticed by Remak that the gray por- tions of the communicating branches con- sisted of fibres which were sent by the sympathetic to the cerebro-spinal nerves to be distributed peripherically with them. On microscopic examination it was found by him that the sympathetic contained a large num- ber of fibres presenting a peculiar structure : these he regarded as the proper organic or sympathetic nerve -fibres, and believed that while the sympathetic derived from the brain and spinal cord all the tubular fibres con- tained in it, the grayer portions of the rami communicantes were composed of organic or sympathetic fibres, which were sent by the sympathetic to the cerebro-spinal nerves, to be distributed peripherically with them. The same view was also adopted by Miiller and others. Valentin, as has been already stated, rejecting the fibres of Remak as being destitute of the properties of nerve-fibres, believed that the rami communicantes con- sisted entirely of fibres sent by the brain and spinal cord to the sympathetic. Volkmann and Bidder, though agreeing with Valentin in regard to the fibres of Remak, still main- tained the opinion, that the rami communi- cantes are of a compound nature, containing fibres which are sent to the sympathetic from the cerebro-spinal nerves, and also others which are sent to the latter by the sympa- thetic, and which belong to the fine variety of tubular fibres already described as probably arising in part from the ganglionic corpuscles. * Selbstandigheit des Sympathischen Xervensys- tems von Bidder und Volkmann, p. 29. t Ibid. t Ibid. On examining the connection between the sympathetic and cerebro-spinal nerves in the frog, they find that all the anterior branches of the spinal nerves communicate with the sympathetic. The filament of communication with the first spinal nerve at its entrance into it divides into two portions, one of which proceeds towards the spinal cord, the other towards the periphery : when it consisted of two portions, the one was directed towards the centre, the other ran peripherically. Con- nected with the second spinal nerve they found several communicating filaments, the smaller portion of the fibres of which ran towards the centre, while the larger portion was directed towards the periphery. The fibres connected with the third nerve also ran in both directions, the chief portion, however, towards the centre. The fourth communicating branch sent its fibres both towards the centre, and also towards the periphery, the portion running centrally, however, being much more considerable than that running towards the periphery. So also in regard to the fifth ; the portion, how- ever, directed towards the centre did not exceed that passing peripherically so much as in the former. Sometimes they found that the central and peripherical portions were about equal. The sixth communicating branch sent about an equal portion of its fibres in either direction. In regard to the seventh, they found that by far the greater portion was directed peripherically, while only a very small bundle took the direction of the centre. Between the eighth nerve and the sympa- thetic there are frequently two communicating filaments : their fibres are directed almost ex- clusively towards the periphery, only a very small portion being directed towards the centre ; and sometimes even this is wanting. Between the ninth nerve and sympathetic there are commonly two, often also three, filaments of communication with the sympathetic; and in one case they found as many as six : the course of the fibres here is similar to what it is in the eighth ; perhaps, however, the portion sent inwards towards the centre is even smaller, and not unfrequently fails alto- gether. The communication with the tenth nerve they found was not constant : some- times three communicating filaments were observed; at others no communication ap- peared to exist. When present, they always ran almost exclusively in the direction of the periphery. Thus, then, of the rami communi- cantes in the frog there appear to be none which consist of fibres entirely derived from the spinal cord, while, on the other hand, some of these consist almost exclusively of fibres which run towards the periphery, and which therefore must be regarded as exclusively consisting of fibres which are sent by the sympathetic to the spinal nerves. The five up- per spinal nerves give to the sympathetic in the frog more fibres than they receive from it, while, on the contrary, the five lower receive from the sympathetic more fibres than they send to it. As regards the communicating 446 SYMPATHETIC NERVE. branches between the sympathetic and cere- bral nerves, they also regard it as probable that the greater number of the fibres in the communicating branches run peripherically. In the fish and bird they also found that the fibres of the communicating branches were di- rected partly towards the centre and partly to- wards the periphery. In small animals belong- ing to the class mammalia, such as the rat and mole, as well as in small dogs and cats, they found, on examining the communicating branches with the microscope as before, that the fibres passed both inwards towards the centre, and also outwards towards the peri- phery, and that the latter in many cases ex- ceeded the former. As already mentioned, there are commonly two branches of communication between each of the spinal nerves and the sympa- thetic in the higher animals. The one of these presents a white appearance, resem- bling more or less the ordinary nerves of the cerebro-spinal system; the other has fre- quently a more gray aspect, approaching in this respect the appearance of the sympa- thetic nerves. Sometimes the white cord presents the appearance of being composed of a white and a grayer portion running to- gether. As regards the minute structure of the rami communicantes, the whiter portion consists entirely of tubular nerve-fibres, both of the coarser and finer varieties ; there are also not unfrequently present fibres which appears to be intermediate in point of breadth. In general the broader variety of fibres ap- pear to be more numerous than those which belong to the finer variety. According to Kolliker, the relation between them is much the same in point of number as in the pos- terior roots of the spinal nerves. The gray portion, as is stated by Todd and Bowman, contains a large proportion of fibres belonging to the gelatinous variety : in young animals it is often entirely composed of structures agreeing in character with the gelatinous fibre. In the full-grown animal also it often, when examined without addition of reagents, presents the appearance of being altogether composed of these fibres. Addition of dilute solution of soda, however, always brings into view a number of tubular nerve-fibres, which belong to the finer variety. The relation be- tween the tubular fibres and those of the gelatinous kind as regards number, is much the same as in many of the branches of the sympathetic, especially in the smaller twigs distributed to the blood-vessels. Occasionally, however, especially in the rabbit and cat, this portion is found to be almost exclusively composed of fine tubular nerve-fibres : the gelatinous fibres being present only in small numbers. In its appearance as seen by the naked eye, as well as in its microscopic structure, the grey portion of the rami com- municantes agrees in character with the branches of the sympathetic, and would ap- pear to be an offset from the same to the cerebro-spinal nerves. This is rendered more probable by the observation of Dr. Beck, that the grey portions on leaving the ganglia send off' small branches to the neigh- Fig. 292. From a gray communicating filament between the sym- pathetic, and one of the lumbar nerves in the Cat, treated with acetic acid, shoiving fine nerve-filres, and nucleated fibres of Remak. (Mag. 250 diam.} bouring vessels, and are reduced in size before reaching the spinal nerves. Moreover, Kol- liker has sometimes observed a small gan- glion present upon them, which, on exami- nation, was found to present the structure of the sympathetic ganglia, and which gave origin to the fibres with which it was con- nected. As regards the white portion of the rami communicantes, there can be no doubt that all the broad tubular fibres contained in it are fibres which are transmitted from the nerves of the cerebro-spinal system. This is proved by the fact that all the tubular fibres which are supposed to originate in the ganglia do not be- long to the broader, but to the finer variety. In regard to the finer variety of tubular nerve- fibres occurring in this portion, inasmuch as similar fibres are present both in the anterior and posterior roots of the spinal nerves, they may be regarded either as fibres sent from the spinal cord to the sympathetic, or they may be fibres which are transmitted from the latter to the cerebro-spinal nerves. On tracing the white portion of the rami communicantes backwards to the spinal nerve, it is found to apply itself to the latter generally in a direc- tion more or less central. On attempting to separate the two by means of needles, though several of the fibres break across, yet the di- rection of these, as well as of the others, ap- pears to be towards the centre. When the corresponding spinal nerve, along with its communicating branch, is dissected out, and SYMPATHETIC NERVE. 447 examined, after addition of dilute solution of soda, with a power of 40 diameters, it is not difficult to observe, in the cat or other small animals, that the fibres composing the white portion run towards the centre. Many of them bend directly inwards to the cord^ while others sink into the spinal nerve, more or less obliquely, still, however, in the direction of the centre. That the fibres in question are not to be regarded as fibres sent from the sym- pathetic to the cerebro-spinal nerves is ren- dered further probable by the fact that they can all be traced beyond the corresponding sympathetic ganglion into the cord above and below. Moreover Kolliker has traced them not only past the ganglia in the main chain of the sympathetic, but into the peripherical branches, and, in small animals, even through the ganglia occurring upon these latter He also finds that the fine fibres in question differ from those which arise in the sympathetic ganglia in presenting a darker contour and in being somewhat broader. As regards the proportion between the fibres in the communicating branches which may be regarded as proceeding from the sym- pathetic to the cerebro-spinal nerves and those which are sent by the latter to the sympa- thetic, we have already seen that in the frog, according to the observations of Bidder and Volkmann, the former exceed the latter con- siderably. In the higher animals it would appear that the reverse is the case ; in the rabbit, according to Kolliker, by far the greater portion of the rami communicantes run towards the centre. In man also, according Fig. 293. Connection between the sympathetic and the sixth intercostal nerve in the Rabbit. K c, communicatin g branch ; c P, intercostal nerve ; c, its central extremity ; p, its peripheral extremity. Most of the fibres of the communicating branch run towards the centre ; several of these, a, a, disappear among the fibres of the intercostal nerve, rather in the direction of the periphery. (Mag. 60 diam.) to the same observer, much the greater number of the fibres contained in these branches run inwards towards the spinal column. I examined most of the rami communicantes in a foetal calf about 2£ feet in length, and have little hesitation in saying that in this animal the proportion of fibres which are directed towards the spinal cord greatly exceeds any that appear to run towards the periphery. At the point of junction with the spinal nerve the communicating branch, when examined with a power of 40 diameters, was seen to spread out somewhat, most of the fibres bent directly inwards towards the spinal cord, others passed into the nerve, either obliquely or at right angles to it, and then curved in- wards towards the spinal cord. In some of the communicating branches, a few of the fibres were seen to join the nerve in the direc- tion of the periphery. In the cat also, the fibres of many of the communicating branches were found to run exclusively in the direction of the spinal cord. The fibres in the different communicating branches, as shown by Wlitzer, Miiller, and others, are connected both with the anterior and posterior roots of the spinal nerves, and it seems probable that the fibres which are sent from the cerebro-spinal system are de- rived from both. Volkmann*, however, as will be afterwards noticed, believes that all the fibres sent to the sympathetic are derived from the posterior root alone. As regards the further course of the fibres which are derived by the sympathetic from the cerebro-spinal system, Valentin f, holding the view that this nerve is entirely composed of such fibres, believed that on joining the * Nerven-Physiologie in Wagners Handworter- buch, Eilfle Lieferung, p. 609. t De Functionibus Nervorum, § 152. 155. See also Quain's Anatomy, by Sharpey. 448 SYMPATHETIC NERVSE. main or gangliated cord they all run in a downward direction towards the pelvic ex- Fig. 294. Fibres from the root of intercostal nerve of a Rabbit. Towards c (in fig. 293.), the nerve chiefly con- sisted of fibres similar to those indicated by B ; towards b it consisted chiefly of broad fibres, A. ; c fibres from the communicating branch. (Mag. 250 diam.) tremity, none passing upwards towards the cephalic extremity. After thus running for a greater or shorter distance in the main cord, they then pass off from it in the peripherical branches, the point at which they leave the cord being always situated lower down than the point at which they entered it. This arrangement was termed by him the lex pro- gressus : he endeavoured to support it by experiments on the motory action of the fibres contained in the sympathetic, showing that when different parts of the cerebro-spinal axis, as well as the rami communicantes, are irritated, the contractions produced in the viscera follow a certain order, which favours the opinion that the fibres are disposed in the manner he states. This view is opposed by Bidder and Volkmann*, on the ground that it is at variance with what is actually ob- served in regard to the course of these fibres on joining the sympathetic. On examining with the microscope the communicating branch at its point of junction with the sym- pathetic, they find that in so far as it consists of cerebro-spinal fibres it divides into two portions, one of which is directed downwards in the direction of the pelvis, while the other passes upwards towards the head. In small animals, such as the rabbit or mouse, it is not difficult, when one of the thoracic commu- nicating branches is examined with the micro- scope, to observe that the fibres are disposed in the manner in which Volkmann and Bidder describe, some passing upwards, others down- wards into the main cord of the sympathetic, and in which they may be traced for some distance, and, according to Kolliker, into the peripheral branches. That they all gradually pass off from the main trunk of the sympa- thetic into its peripheral branches is pro- bable, as Kolliker observes, from the fact that most of these contain a greater or smaller number of fibres resembling those in question. Peripherical Distribution. — The different branches of the sympathetic contain the same structures as those which have been already described as constituting the main trunk of the nerve, viz. broader and finer tubular nerve- fibres and fibres of Remak. These, however, vary in the proportion in which they are pre- sent in the different branches. In the whiter branches of the sympathetic, such as the splanchnic nerves, the number of tubular nerve-fibres, as compared with the number of the fibres of Remak, is much the same as in the main trunk. The grayer branches, on the other hand, such as the ascending or carotid branches of the superior cervical gan- glion, the nervi molles as well as the arterial branches generally contain a large number of the fibres of Remak. Many of them appear to be entirely composed of these and fine tubular fibres. The nerves which are distri- buted to the heart are also chiefly composed of fine tubular fibres and fibres of Remak. In the heart of the sheep many of the branches which run along the surface of the ventricles are chiefly composed of the latter variety of fibres, there being few tubular fibres present. As already mentioned, numerous small gan- glia have been described by Remak as oc- curring on the cardiac nerves, both on the surface and also in the substance of the organ. As regards the fibres on the inner surface of the heart, they cannot be distinguished by the naked eye. If, however, the lining membrane is dissected carefully off from the muscular substance, and then, after addition of diluted solution of soda, examined with a power of 250 diameters, they may frequently be ob- served. They consist of tubular nerve-fibres belonging to the finer variety, and are arranged * Die Selbstandegkeit, &c., p. 31. SYMPATHETIC NERVE. 449 in bundles containing from six to three nerve- tubes forming a widely-meshed network. The rami intestinales present much the same cha- racters as the nerves of the heart. Many of . 295. n Communication between the sympathetic and third spinal nerve in the Frog, showing the arrangement of the fibres of the communicating branch at its points of junction with the spinal and sympathetic nerves. H P, sympathetic nerve ; H, 'cephalic side of the same ; p, pelvic, c P, spinal nerve ; c, its central, and P its peripheral end. a, portion of communicating branch running centrally; b, portion of ditto running pheripherically ; c and d, fibres of the ramus communicans passing upwards in the direction of the head, and downwards towards the pelvis; #,£, ganglion-cells ; h, pigment. (After Bidder and Volkmann.} the fibres seem to become lost in the muscular coats of the intestine; a few slender twigs, particularly in the stomach, can be traced through these to the mucous or submucous coats. The nerves of the unimpregnated uterus also contain a considerable number of the fibres of Remak. In the impregnated uterus of the cow, some of the twigs which run along the cervix of the organ consist almost entirely of fine tubular nerve-fibres ; in others the fibres of Remak are more numerous than the tubular nerve-fibres. Ganglia have been observed by Remak on the nerves distributed to the mus- cular substance of the cervix uteri in the pig. Small ganglia are also present in the impreg- nated cow's uterus, both en the nerves passing to the organ and also in the twigs which pass upwards along the posterior wall of the cervix of the uterus. Some of them contain as few as from six to nine ganglionic corpuscles : they seem to be more numerous, and are larger near the point where the cervix uteri becomes continuous with the vagina. Divi- sions of the fine tubular nerve-fibres have been observed by Kilian*; he describes a fibre belonging to the finer variety as dividing into two branches, and each of these, after running a short distance, as again dividing. As regards the nerves of the urinary bladder, in that of the ox they are very numerous, especially towards the neck and posterior aspect of the organ, and present a more or * Henle and Pfeuffer's Zeitschnft, p. 222. Supp. less white appearance. Some run beneath the peritoneal coat, others between the deep and superficial layers of muscular fibres ; and some may be traced through these to the mucous coat. At first the branches contain both broad and fine tubular fibres : in their farther course, only fine fibres appear to exist. There are present, especially towards the cervix of the organ, a number of small ganglia similar to those in the uterus. Ganglia have also been described by Miiller as occurring on the nerves distributed to the cavernous tissue of the penis. The branches of the sympathetic which pass to the different glandular organs also consist chiefly of fine nerve-fibres and fibres of Remak. In general there are more or fewer fibres belonging to the broad variety also present. In the substance of the organs they run in company with the blood-vessels and with the ducts of the glands, and appear to be chiefly distributed to these : at least no nerve-fibres have as yet been discovered run- ning separate from the vessels or ducts in the parenchyma of the organ. In the finer rami- fications of the nerves, the broader tubular fibres gradually disappear. The fine fibres also lose their distinct dark margins, and become pale and more or less indistinct. Their exact mode of termination has not been determined. Pappenheim, however, describes the nerves of the kidney as ter- minating in a looped arrangement. Small ganglia occur on the nerves distributed to G G 450 SYMPATHETIC NERVE. many of the glands : they have been seen by Ludvvig on the nerves of the kidney ; also by Fig. 296. Fourth thoracic ganglion of Rabbit ; showing the course of the fibres contained in the communicating branch after reaching the sympathetic. A B, main cord of sympathetic ; A, cephalic, B, pelvic extremity; c, communicating trunk; g, ganglionic corpuscles ; a, portion of the fibres in the communicating branch passing towards the pelvic extremity ; &, ditto passing towards the head. {Magnified 70 diameters.) Pappenheim on the nerves distributed to the supra-renal capsules. Schaffher* has also ob- served ganglionic corpuscles from which nerve-tubes proceeded, in the substance of the lymphatic glands. Small ganglia have also been described by Remak as occurring on the nerves distributed to the bronchi : they have also been observed by Kolliker. The latter observer believes that he has seen nerve-tubes arise from them. From the observations of Purkinje* it would appear that numerous fibres of the sympathetic pass to the cerebro-spinal mem- branes. In the dura mater of the cranium he describes the nerves as most abundant in the neighbourhood of the trunks of the three meningeal arteries. Most of them accom- pany the vessels ; but there are also others which leave them and ramify in the mem- brane. In the pia mater of the cerebellum the nerves which branch separately from the arteries are not so numerous as in the pia mater of the cord The nerves in the pons and cerebrum belong exclusively to the ar- teries : no trace of nerve-fibres was seen in * Vermischte Beobachtungen in Ilenle und Pfeuffer's Zeitschrift, band vii. p. 177. f Mailer's Archiv. 1845. the choroid plexuses. Around the vena Galeni magna they form a dense plexus which passes into the tentorium cerebelli, and seems to belong to it rather than to the venous system. The nerves in the pia mater of the cord unite with those of the cerebellum and pons. In the pia mater of the spinal cord the nerves are more abundant than in any other part of the cerebral membranes ; they run singly or in bundles of two and three ; others contain from thirty to fifty fila- ments. Sometimes fibres leave the bundles, forming loops and returning to the same or to a different bundle. The largest bundles are situated near the anterior spinal artery, which they entwine; and some pass from this into the process of the dura mater in the anterior fissure, and form loops in the same. Other large bundles, running mostly in a longitudinal direction, are situated near the ligamentum dentatum and posterior median line of the cord. Near the origins of the spinal nerves the bundles of sympathetic fibres are not so numerous and are also smaller. Some of these fibres spring from the cerebro-spinal nerves, and enter with the arteries through the intervertebral foramina. In the perito- neum nerve-fibres have been described by Bourgery* as existing in considerable num- bers. They have also been observed by Luschka.-f- Nerve-fibres are also abundant in the periosteum, both that which invests the shafts of the bones and the articular extremi- ties of the same, as shown by the observations of Pappenheim.J They are chiefly situated in the outer part of the membrane, and either run in company with the vessels or are situ- ated upon them. They terminate in loops. Nerves also exist, according to the same author, in the cellular tissue which surrounds the ligaments, penetrating these along with the arteries, and terminating in a series of plexuses and loops. In the tendons they are also sometimes present. Wherever (accord- ing to Pappenheim) vessels pass to ligaments or tendons, nerves pass also. DEVELOPMENT. — In the cow's embryo of 8^- lines in length, the gangliated cord of the sympathetic in the thorax was observed, by Kiesselbach §, on either side of the spinal column in the form of a thick cord, presenting numerous inequalities. In the pig's embryo, eight lines in length, it presents, according to Valentin, the same aspect. It seems, at this period, to consist of a series of small ganglia placed almost in juxta-position to each other, the interval between the individual ganglia not being very distinct. In another embryo, measuring about thirteen lines in length, Bis- choff found the gangliated chain distinctly formed, not only in the thoracic, but also in * Comptes rendus, 1845, p. 566. t Luschka, die JStructur des Serosen Haute des Menschen, quoted in Canslatt's Jahresbericht. j MUller's Archiv. 1843. § Disser. Syst. Histor. Formationis ac Evolution! Nervi Sympathici: Munich, 1835 ; quoted in Bishoff's Entwikelung und geschichte, French Translation. SYMPATHETIC NERVE. 451 tne cervical region : the superior cervical ganglion presented the aspect of a small round nodule. In the cow's embryo, measuring Fig. 297. Re Sixth thoracic ganglion of the left side, from the sym- pathetic of a Rabbit, treated with soda, and magni- fied forty diameters. Tr, main cord of sympathetic ; Re, Re, commu- nicating branches, each dividing into two portions ; Spl, splanchnic nerve ; S, small nerve proceeding probably to the blood-vessel ; G, ganglion-cells and libres, passing into the main cord of the sympathe- tic. (After Kolliker.} about li inches in length, I found the ganglia in the cerebral and spinal nerves, as well as those of the sympathetic, very distinct. The superior cervical ganglion of the sympathetic appeared as a small reddish grey mass, of an irregularly oval form, measuring about ^'-tn of an inch in its longest diameter, soft and breaking clown readily. It was situated close to the pneumogastric, a narrow indistinct whitish line passing downwards from the lower part of the ganglion to that nerve. The lower cervical ganglion presented a more elongated form, and appeared to be prolonged into the first thoracic : the other thoracic ganglia appeared as minute greyish particles between the heads of the ribs, and measuring about -^th of an inch in diameter. The ganglia in the lumbar and sacral regions pre- sented in general a more elongated form, and were not so distinctly separated from one another : the connecting cord, especially in the sacral region, being short and thick, and looking as if it were a prolongation of the one ganglion into the other. None of the branches which are sent inwards from the sympathetic cord, nor the ganglia occurring upon them, could be accurately distinguished from the surrounding structures. As regards the ganglia occurring on the cerebral and spinal nerves, they were much more distinct than those of the sympathetic. The Gasserian ganglion presented the form of a greyish white body, situated beneath the still soft and transparent dura mater : it measured about y'jth of an inch in diameter, and presented an irregularly oval or triangular shape. It ap- peared to consist of several opaque portions, separated from one another by an intermediate more or less transparent substance, thus pre- senting the appearance of being composed of several minute lobules. The ganglia on the posterior roots of the spinal nerves were also very distinct : they were arranged along the interior of the spinal canal, on each side, and rather anteriorly towards the bodies of the vertebrae, and concealed by the spinal cord. They presented an oblong or oval shape, mea- sured about ^th of an inch in length and about g^-th in Breadth, and presented the same characters in regard to colour, &c., as the Gasserian ganglion. In embryos from seven to eight inches in length, the superior cervical ganglion presents the same oval shape and reddish grey appear- ance as before : it is larger, however, measuring about ygth of an inch in its long diameter: it consists, as before, of a number of opaque round or oval portions : the intermediate sub- stance exists in much smaller quantity. It is surrounded by a highly vascular sheath. From its lower part the communicating cord is seen passing downwards for a short dis- tance, when it is applied to the trunk of the pneumogastric. The cord presents a flat- tened aspect, and is of a greyish red colour. The ganglia in other regions of the body, as well as the intermediate cord, are well formed, and much larger than before. The first sacral ganglion of either side appears to be amalgamated into a single ganglion situated in the medial line. The splanchnic nerves and solar plexus, as well as its offsets, are distinctly visible. The rami communicantes are also present ; so also the plexus on the abdominal aorta and epi- gastric plexuses. The ganglia on the cerebral and spinal nerves present the same characters as before, with the exception that they are considerably larger. In embryos measuring seventeen or eighteen inches in length, not only can the parts which have been already mentioned be distinctly seen, but also most of the peripherical branches of the sympathetic. The superior cervical ganglion presents, as before, a more or less oval shape, and measures about ^th of an inch in its long diameter. It has still the appearance of being composed of a number of round or oval opaque greyish- white masses : there appears, however, to be very little of the intermediate transparent substance present. Its sheath is very vascular, and numerous vessels also pass into the interior of the ganglion between its lobules : it is possessed of considerable con- sistence. Its branches of communication with the different nerves are also distinctly seen : they have a more or less greyish red ap- G G 2 452 SYMPATHETIC NERVE. pearance. The lower cervical ganglion pre- sents an irregularly oblong shape, about -Jth of an inch in length and -j'^th of an inch in thickness, and still has the appearance of being prolonged downwards into the first thoracic ganglion. The thoracic ganglia are much smaller, measuring about TVtn of an inch ; and are more or less triangular in shape, present- ing the lobulated aspect above described. The connecting cord between the different ganglia has a reddish grey colour, is flattened, mea- suring about r,Vtn of an inch in breadth, and presents the appearance of consisting of dis- tinct bundles of fibres. A portion of these can be traced over the surface of the ganglia, others appear to sink into them, while a con- siderable number can be traced into the rami communicantes. The latter are very distinct; some of them in the thoracic region appear to be almost as thick as the cord of the sympa- thetic itself, and all of them present the same greyish red appearance. On turning inwards to the sympathetic, many of their fibres are seen to be prolonged into the main cord of the sympathetic, and merely run along the sides of the corresponding ganglia : these pass both upwards towards the head, and down- wards in the direction of the pelvis. They join the spinal nerves at the point where the anterior and posterior roots become united into a common trunk. By far the greater portion of the fibres in the rami communi- cantes run inwards towards the spinal cord. The splanchnic nerve, which is about jth of a line in thickness, has a whiter aspect than the main cord of the sympathetic. The nerves on the surface of the heart are very numerous and distinct, presenting the same arrangement as has been already de- scribed. The cceliac and epigastric plexuses are also large ; the latter containing several ganglia. There are also several small ganglia in the plexus upon the abdominal aorta. The ganglia on the cerebral and spinal nerves present much the same appearance as those in the animal after birth, only they are softer and have a redder colour. As regards the development of the sympa- thetic in the human subject, it would appear from the observations of Lobstein*, that iu the embryo of the 14th week, about three inches in length, the main cord of the nerve was very apparent. In the chest it constituted a thick cord of a red colour, the ganglia being closely approximated towards one another. The superior cervical ganglion was very well formed, and about two lines in length, and half a line in thickness. The great splanchnic nerve existed as a very delicate filament : the semi- lunar ganglia were almost imperceptible. In an embryo male, about five months, old and measuring six inches in length, Lobstein found the trunk of the sympathetic very dis- tinctly developed. It constituted an uninter- rupted cord extending from the base of the cranium to the pelvis. The superior cervical * De Nervi Lympathici humani fabrica, usu, et morbis, cap. iii. p. 47. ganglion was rounder than in the adult : it was three lines in length, and about half a line in thickness. The greater splanchnic nerve was very distinct, but very delicate, and arose by three roots. The semilunar ganglia were small, indistinct, and measured only about half a line in their greatest diameter. They were adherent to the supra-renal cap- sule and to the vessels. The thoracic ganglia, with the exception of the first, constituted little enlargements about half a line thick. According to Kiesselbach, the solar ganglia do not make their appearance until about the 7th month. At the 5th month, he found the ophthalmic and subrnaxillary ganglia formed ; and about the 6th month, the spheno-palatine ganglion appears ; and in the 5th month, ac- cording to the same author, the communi- cating branches between the sympathetic and cerebro-spinal system appear. In the foetus of eight months, the superior cervical ganglion, according to Lobstein, mea- sures about five lines in length, and a line and a half in breadth. The greater splanchnic nerve is very distinct, but very fine, and terminates in ?n imperfect semi-lunar ganglion. In the foetus, at the full period, the superior cervical ganglion, according to Lobstein, mea- sures about 8^ lines in length, and furnishes four filaments to the branches of the external carotid, while a fifth is lost on the crico- thyroid artery. The thoracic ganglia are well formed, and measure about a line in diameter, with the exception of the first, which mea- sures about 5 lines. They are of a red colour ; and nearly all of them receive two branches from the intercostal nerves. The trunk of the sympathetic is very thick ; the interval between the ganglia is about -^th of a line. The lumbar ganglia are very apparent. The semilunar ganglia are of small size com- pared with the other ganglia. Lobstein failed to find the coccygeal ganglion in the child immediately after birth; according to Kiessel- bach, on the other hand, it appears about the fifth month. A, ganglionic corpuscles from the Gasserian ganglion of a calf 1 \ inch in length ; B, nerve- fibres from the same ; c, from one of the thoracic ganglia of the sympathetic in the same animal. With respect to the minute structure of the ganglia and nerves in the foetus, the Gas- serian ganglion in the foetal calf, H inch in length, consists of the following elements : 1st, bodies measuring from the ^nnnrth to the SYMPATHETIC NERVE. 453 of an inch in diameter, and presenting a slightly granular surface (most of them are round ; others have more or less an oval shape) ; 2nd, distinct cells measuring from the TTjtarth to the T2Votn °f an lncn U1 ('ia" meter : they contain a finely molecular fluid, and also a nucleus. The latter, which is fre- quently situated towards one side of the cell, is round and granular, and generally contains a nucleolus. With the exception of their smaller size, they resemble ordinary ganglionic cor- puscles. The nerves in the ganglion present the aspect of flattened bands of blastema, consisting almost entirely of corpuscles re- sembling those first described, arranged close together in linear series in a somewhat gra- nular matrix. They vary in breadth consi- derably. The ganglia on the posterior roots of the spinal nerves present the same struc- ture. The sympathetic ganglia appear to be en- tirely composed of structures similar to those first described, imbedded in a more or less granular transparent blastema. In embryos of 6 to 8 inches in length, the sympathetic ganglia still contain a large num- A, Ganglion- corpuscles from the Gasserian gan- glion of a calf 7 inches long; B, nerve-fibres from the brachial plexus of the same animal ; c, from the superior cervical ganglion of the sympathetic ; D, nerve-fibres from the main cord of the sympathe- tic in the thorax. ber of corpuscles similar to those in earlier embryos. There are also present a number of bodies larger than these, and consisting of a distinct cell-wall inclosing, besides a nucleus, a finely-granular fluid. They are commonly round ; some are more or less eiig-shapcd. The nucleus in the latter is generally situated towards the wider extremity of the eel1, while its narrow end is prolonged into a delicate, granular process about the -s^tyth of an inch in breadth. The nerves in the gan- glia do not differ much in appearance from those in the Gasserian ganglion of the embryo of H inches in length. The sympathetic cord and branches present the same structure. In the ganglia of the cerebro-spinal nerves, the ganglionic corpuscles are larger and more dis- tinctly formed than in the sympathetic ganglia. Many of the cells have processes similar to those above described ; and in several of these, at a short distance from the corpuscle, there is a small oval nucleus such as Kolliker describes in the human embryo of 16 inches. The nerves belonging to the cerebro-spinal system are also much further developed than those in the sympathetic. Those in the bra- chial plexus present the appearance of being composed of a slightly-granular transparent blastema, marked by longitudinal striae, and containing embedded in it oval granular nuclei. The striae are arranged parallel to one ano- ther, and evidently correspond to the margins of the nerve-fibres. The nuclei are arranged at intervals, and occupy the entire breadth of the fibres. There is no trace of the white substance of Schwann. Fig. 300. From, the semi-lunar ganglion of a Calf 18 inches long. a, portion of ganglion ; b, corpuscles isolated ; c, nerve-fibres connected with the ganglion. In the sympathetic ganglia of embryos measuring 18 or 19 inches in length, there are still present a considerable number of granular corpuscles measuring from the 4oVotn to the -y-,1— th of an inch in diameter, similar to those already described. They are chiefly com- posed, however, of cells resembling those in the ganglia after birth, only smaller and more delicate. The nerve-fibres in the ganglia have much the same appearance as those already described in the brachial plexus of embryos from 6 to 8 inches in length. In the ganglia occurring on the posterior roots of the spinal nerves, the Gasserian ganglion, and the gan- glion on the trunk of the pneumo-gastric, the ganglionic corpuscles differ from those in the perfect animal only in point of size. Most of the nerve-fibres connected with the ganglia present the same tubular character as the perfect nerve-fibre. The nerve-fibres in the roots of all the cranial nerves present the dis- G G 3 SYMPATHETIC NERVE. tinctly tubular character also ; in those of the 3rd, 4th, and 7th, the double contour is more Fig. 301. From the Gasserian ganglion of the same animal as the preceding figure. a, portion of ganglion with corpuscles in situ; I, three corpuscles included within a single capsule ; c, ganglionic corpuscles freed from their capsules ; dj nerve-tubes connected with the ganglion. or less distinctly visible. The optic nerve con- sists of fine tubular fibres mingled with small round or oval bodies. The nerve-fibres in the brachial plexus also present the character of perfect tubular fibres ; they are narrower than in the adult animal. So also the fibres in the trunk of the pneumogastric ; throughout the entire extent of the trunk of this nerve, in the neck and upper part of the thorax, there were embedded amongst its fibres ganglionic corpuscles similar in their character to those occurring in the ganglia of the cerebro-spinal nerves. Sometimes a single corpuscle lay imbedded in a bundle of nerve- fibres ; in other parts two were seen, one situated above the other ; and in some parts there were as many as six, all arranged close together in linear series ; some of them were seen to give off a nerve-tube at one extremity ; and once or twice the corpuscle was seen to be connected with two such, one passing towards the centre, the other in the direction of the peri- phery. The main cord of the sympathetic appears to be entirely composed of fibres presenting the nuclear character, similar to those already described in connection with its ganglia, and representing an early stage of the development of the cerebro-spinal nerve-fibres. Addition of dilute solution of soda brings into view a few tubular nerve-fibres similar to those in the spinal nerves. The splanchnic nerves present the same structure as the cord of the sympathetic, containing a few tubular nerve- fibres, but being chiefly composed of the other structures. In one of the nerve-filaments from the surface of the right ventricle of the heart, Fig. 302. A, nerve fibres from the brachial plexus of a Calf 18 inches long. B. a, nerve-fibres from the sympa- thetic cord in the thorax ; b, the same treated with dilute solution of soda, showing the presence of tubular nerve-fibres, 1 1, similar to those in the cerebro-spinal nerves. there were no tubular nerve-fibres present ; it consisted entirely of structures similar to those already described. As regards the communi- cating branches, all of them contained more or fewer tubular nerve-fibres ; some appeared to be entirely composed of these, while others consisted chiefly of the partially- developed nerve-fibres. The difference in point of struc- ture between the fibres in the cerebro-spinal nerves and those occurring in the sympathetic is at this period of embryonic life very re- markable : while the former present for the most part the tubular character of the per- fectly-formed nerve-tube, the latter appear to consist of a mass of blastema with numerous granular nuclei imbedded in it, corresponding, in short, to the fibres of the cerebro-spinai system in the foetus measuring 6 to 8 inches in length. This also applies, though perhaps in a less degree, to the ganglia of the sympa- thetic as compared with those on the cerebro- spinal nerves, the latter being more fully developed, both as regards their ganglionic corpuscles and nerve-fibres, than the former. As regards the further development of the nerve-fibres of the sympathetic, it would ap- pear, from the observations of Volkmann and Bidder, that they undergo little further change during the whole period of embryonic life. SYiMPATHETIC NERVE. 455 At least, in embryos near the full time, they observed little change in the sympathetic nerve-fibres. It has been already stated that in the sym- pathetic of embryos of 18 or 19 inches in length there are some tubular fibres present ; these, probably, are to be regarded as fibres sent from the cerebro-spinal system. PHYSIOLOGY. — The actions which take place in the animal body may be divided into two classes. Those which are included in the one class are entirely under the guidance of volition ; those which belong to the other not only take place independently of any effort of the will, but are also more or less completely removed beyond its control. The movements which occur in the muscles of the limbs, and in most of the muscles of the trunk, form examples of the former ; while the movements of the internal muscular organs, such as those of the heart, intestinal canal, and genito-urinary organs, afford ex- amples of the latter. To the latter also be- long the acts of nutrition, secretion, &c., commonly termed the vegetative processes. Several of the latter, as the movements of the heart, go on without interruption during the entire life of the individual; while others, as the movements of the intestinal canal, take place at irregular intervals, depending ap- parently on the application of external stimuli to the free surfaces of the organs in which they are manifested. The exercise of the former class of actions is moreover attended by sensation ; that of the latter, in the normal condition, not. The impressions which are constantly being made by the blood upon the inner surface of the heart and vessels never reach the sensorium ; we are also insensible to the impressions made by the food upon the free surface of the intestinal canal, as well as to the contractions thereby induced. In like manner, the acts of nutrition and secretion take place entirely without our knowledge. The feeling of weariness also which ensues after exertion of the voluntary muscles, is never felt so far as the heart is concerned, although its action is constant, and just as little in re- gard to the other organic muscles. The organs in which the former class of actions takes place are supplied with nerves which proceed directly from the brain and spinal cord ; those whose actions belong to the second class derive their nerves chiefly from the sympathetic. Guided by this difference in character be- tween the vital phenomena, Bichat divided life into animal and vegetative ; the former characterised by the circumstance of its phenomena coming within the range of sen- sation and volition ; the latter including those acts which are more or less completely re- moved beyond the sphere of the will and of the consciousness. In accordance with this division, he also separated the nervous system into two portions : the one corre- sponding to the cerebro-spinal system, pre- siding over the functions of animal life ; the other corresponding to the sympathetic, pre- siding over the involuntary movements, and over the processes of nutrition and secretion, or functions of vegetative life. The sympa- thetic and its ganglia are, according to the views of Bichat, entirely independent of the cerebro-spinal system of nerves. The various ganglia of the sympathetic he regarded as so many distinct nervous centres, each presiding over the actions of the parts to which it sends nerve-filaments, and each discharging its func- tions without any relation to the brain or the spinal cord. The involuntary nature of the processes which take place in organs supplied by the sympathetic, as well as the circum- stance that the normal impressions which are made upon the free surfaces of these do not reach the sensorium, rendered the views of Bichat highly probable. In diseases of the brain and spinal cord, as in tetanus and chorea, where the muscles supplied by cerebro- spinal nerves are all thrown into a state of more or less violent contraction, the muscular organs which derive their nerves from the sympathetic, such as the heart, continue their movements as before. So also a stimulus ap- plied to the brain or spinal cord, causes con- tractions in the muscles which derive their nerves from these parts, but does not, ac- cording to Bichat, produce any effect on the movements of parts which are supplied by the sympathetic. The fact that embryos in which the central masses of the nervous system are wanting may reach an advanced stage of development, showed that the pro- cesses of vegetative life might go on perfectly, independently of the influence of the cere- bro-spinal system, while the circumstance that in these the sympathetic system of nerves was always present, and in a high state of develop- ment, seemed at the same time to indicate the connection subsisting between it and the processes in question. The views of Bichat were generally adopted by physiologists until comparatively recent times, when they were ably combated by Valentin, who endeavoured to establish the doctrine, commonly held before the time of Bichat, that the sympathetic and cerebro- spinal nerves do not constitute two distinct and independent systems, but that the former is dependent upon the latter for all its pro- perties, and is in this respect to be regarded as one of the cerebro-spinal nerves. The in- voluntary and apparently spontaneous nature of the movements which take place in organs supplied by branches of the sympathetic, affords no argument, according to Valentin, for supposing that their action is not regu- lated by the brain and spinal cord, or that the sympathetic is independent of these parts of the nervous system, inasmuch as the same character is also presented by the movements of certain] organs which are undoubtedly supplied by cerebro-spinal nerves. This, for example, is the case with the rhythmical movements of the muscles of respiration. Again, there are organs which are supplied by nerves of cerebro-spinal origin, and which notwithstanding resemble the organs supplied G G 4- 456 SYMPATHETIC NERVE. by the sympathetic in the circumstance that the normal impressions which are made upon them do not reach the sensorium. Thus, the greater part of the mucous membrane which lines the bronchial tubes, as well as that of the oesophagus, receives its nerves from the eighth pair; the lacrymal glands receive fila- ments from the fifth nerve ; and from the fifth and seventh nerves fibres are distributed to the salivary glands : and yet all these organs present the same relations in regard to sensi- bility as the pancreas or other glands which derive their nerves from the sympathetic. The fact of certain parts being beyond the control of the will, and from which the or- dinary impressions they receive are not con- veyed to the sensorium, does not so much depend on any peculiarity in the nerves with which they are supplied, as upon their ana- tomical constitution. Such is the case, for example, with the muscular fibres presenting the same characters as those which are found in the walls of the ducts of the various glands, as well as with those which are present in the coats of the blood and lymphatic vessels. That the impossibility of influencing these structures by any effort of volition, as well as the fact of their being removed from the sphere of sen- sation, do not depend on any peculiarity in the properties of their nerves, is shown, Valen- tin says, by the fact that the greater part of the nerves for the salivary glands are derived, as above stated, from the fifth and seventh cerebral nerves. The same thing also holds true, according to him, of the mammary glands, the nerves supplied to which proceed chiefly from the supra- clavicular and inter- costal nerves. As regards the argument which is drawn in favour of the views of Bichat, from anencephalous foetuses, Valentin re- marks that there is no evidence to show that in the development of the various organs in the foetus nervous influence is at all concerned ; and, moreover, that the phenomena of growth and nutrition are not dependent on the sym- pathetic is shown by the circumstance of few or no sympathetic fibres being sent to the extre- mities. The sympathetic is moreover capable of transmitting stimuli to and from the cerebro- spinal centres, in the same manner as the ordi- nary nerves arising from these, though in a less degree; stimulus applied to the spinal cord being capable of exciting contractions in the heart and intestinal canal, while on the other hand stimuli applied to the latter may also be trans- mitted to the former. This is shown bv the severe pain which is felt in organs supplied by the sympathetic, when affected with disease, as well as by the circumstance that irritations of the intestinal canal not unfrequently give rise to contractions in the muscles of animal life : as is not unfrequently the case with children, when the presence of worms in the intestinal canal gives rise to impressions which are convened along the centripetal nerves to the spinal cord, and are there trans- ferred to the motor nerves \vhich pass to the voluntary muscles, exciting them to contrac- tions. As already stated, Valentin believes that all the true nerve-fibres which are pre- sent in the sympathetic, are derived from the brain and spinal cord ; on entering the sym- pathetic they pass through a greater or smaller number of its ganglia, and are then distributed to the different organs, in the same way as the ordinary cerebro-spinal nerves. The sympathetic is therefore, according to him, a cerebro-spinal nerve, possessed of the same properties, and deriving these from the same source as the other cerebro-spinal nerves ; the only peculiarities in the sympathetic being its numerous points of origin, as well as the large number of ganglia which it presents. Similar views are also held by Longet*, and others. After the discovery of the gelatinous fibres in the sympathetic, it was held by some, that while motion and sensibility in the organs sup- plied by this nerve depended upon the. tubu- lar nerve fibres sent to them through the medium of the branches of the sympathetic by the brain and spinal cord, the processes of nutrition depend upon the gelatinous or pro- per sympathetic fibres. Moreover, as these fibres are found in the cerebro-spinal nerves also, it is supposed that they pass to the ex- tremities along with the cerebro-spinal nerves, where they in like manner preside over the nutrition of these parts. According to these authors, the ganglia are so many centres, from which nerve fibres, possessing peculiar pro- perties, pass off' in different directions ; some to the viscera, others to the extremities, along with the cerebro-spinal nerves, and by means of which the nutritive processes are regulated. Thus, while the internal viscera receive sen- sory and motor nerve fibres from the brain and spinal cord, they, as well as the organs of animal life, receive the nerve fibres which regulate the nutritive processes from the sym- pathetic. Such seems to be the view of Remakf, R. Hall^I, and others. Volkmann$ adopts the same view as was held by Bichat, regarding the sympathetic as constituting a system of nerves distinct from and independent of the cerebro-spinal system. Under the term sympathetic, he includes not only the sympathetic, commonly so called, but also the ganglia which occur on the pos- terior roots of the spinal nerves, as well as those which are present on several of the cerebral nerves. All the finer nerve fibres are regarded by him as sympathetic fibres. These originate in the different ganglia ; some of them pass inwards to the viscera, over whose movements and nutrition they preside, while others pass along with the cerebro- spinal nerves to the extremities, and serve as the nerves of nutrition to these parts. Each of the ganglia he regards as a nervous centre. * Anatomie et Physiologic de Systeme Xerveux, tome ii. p. 5G9. et seq. j- Observat. Anat. et Microscop. de Systemat. Nerv. Structural, Berlin, 1838. J Edinburgh Medical and Surgical Journal, July, 1846, &c. § Wagner's Handworterbuch der Physiologic Zehnte Lieferung, p. 499. SYMPATHETIC NERVE. 457 By the term centre, Volkmann seems to mean an organ which serves as a regulating appa- ratus, and by which several separate and simple acts are combined into a single com- plex organic act. The contraction of a muscle is a simple act ; in the act of respiration we have the contractions of many muscles com- bined into a single complex act, their com- bination being dependant on a power situated in the medulla oblongata, which part of the nervous system is therefore termed their cen- tral organ. The question then in regard to the independence of the sympathetic is, whe- ther, in the sphere of the organic nerves, there be such combinations, and whether these have their centre in the brain and spinal cord, or in the sympathetic. The brain is the centre of all psychical acts ; it is therefore evident that the sympathetic, in so far as regards all the phenomena of sensation occurring in its sphere, must be regarded as dependent on the brain. But after the brain and spinal cord have been destroyed, does the sympathetic still remain active, and in such a state of activity as implies the co-operation of a cen- tral organ ? Muscular motion implies the activity of the motor nerves, and the activity of those muscles which are supplied by the sympathetic must imply the activity of sym- pathetic nerve fibres. The action of the heart, however, as well as the circulation, sometimes continues for weeks after the de- struction of the central masses of the nervous system. Thus Bidder removed with great care the arches of the second cervical ver- tebra, so that little blood was lost during the operation, and then completely destroyed the spinal cord. Frogs treated in* this way often lived six weeks, sometimes ten, the circula- tion, as seen in the web of the foot, remain- ing at the same time active, and not differ- ing from that in uninjured frogs. The heart beat powerfully and quickly: in a freshly- killed frog, in winter, the heart pulsated thirty- fiva times in the minute ; while in a frog, the spinal cord of which had been destroyed twenty-six days previously, the pulsations were forty per minute. When the brain and spinal cord were destroyed, the medulla ob- longata being left, frogs were retained in life until the sixth day ; and when the entire cen- tral organs of the nervous system were re- moved, they lived until the second day; the rapidly ensuing death in the latter case being due, according to Volkmann, to the effects produced upon the respiration. Within a few weeks after the destruction of the spinal cord the muscles of animal life were found to have lost their irritability in a marked degree, and still later no contraction could be produced in them by application of chemical or me- chanical stimuli ; the heart, however, in such cases still continued to pulsate eleven times in the minute, and retained its property of responding to external stimuli. The intes- tinal canal, in like manner, retained its irrita- bility ; application of stimuli giving rise to contractions which were sometimes of a local nature, at other times extended for a con- siderable distance on either side of the part stimulated. Digestion, in like manner, suffers but little from destruction of the central parts of the nervous system ; healthy frogs, and others, which had been operated upon, were, after being starved for a considerable time, fed with worms, and kept in separate glasses. In the one, as well as in the other, the worms were found after twenty-four hours to be fully digested, and the stomach and duodenum were filled with coloured mucus ; such was observed to be the case even in animals whose spinal cord had been destroyed twenty-six days previously. The secretion of urine also continues : when in animals in which the brain or spinal cord had been removed, the bladder was emptied by external pressure upon the walls of the abdomen, in a short time it again became filled and distended to an enormous size, unless emptied in the way just mentioned. It had been observed by Valentin and Stilling that after destruction of the spinal cord in the frog, different derangements in the nutritive processes ensued ; there were frequently ob- served dropsical swellings, especially of the limbs. On these also, sores formed, which often penetrated as far as the bones. In re- ference to these results, Volkmann states that they are, as shown by Bidder, chiefly accidental. Bidder found that when the bottom of the vessels in which the frogs were kept was covered, not with water, but with moist grass or moss, no such degenerations ensued. The rapid death which ensues in warm-blooded animals, when operated upon in the above manner, depends, according to Volkmann, upon the difficulty of sufficiently keeping up the respiration by artificial means, as well as upon the loss of blood and diminu- tion of animal heat. The circumstance, then, that a certain number of the vital phenomena disappear suddenly and irrevocably after de- struction of the spinal cord and brain, while others continue for a greater or shorter time, and this very perfectly, can only de- pend, according to Volkmann, upon the cir- cumstance that the brain and spinal cord is a necessary condition for the existence of the former, but not for that of the latter. If the latter depend upon certain nervous organs, and if the nerves of the vegetative organs do not require, as a fundamental condition of their activity, the presence of the brain and spinal cord, the only possible centres on which they can depend for this are the ganglia of the sympathetic. The sympathetic and its ganglia, then, constitute, according to Volk- mann, an independent whole, from which proceed the impulses to as well as the regula- tion of those actions which continue after the brain and spinal cord have been destroyed, and which notwithstanding require the co- operation of a central organ. That the move- ments in question require such an organ, and are not produced by the mere stimulus of the blood, faeces, air, &c., in the same way as the twitchings of the muscles in a frog's leg are produced by galvanism, is shown, according 458 SYMPATHETIC NERVE. to Volkmann, by the different characters ex- hibited by the two. When stimulus acts im- mediately on motor nerve fibres, contraction ensues only in that muscle or part of the muscle to which these are distributed ; when it affects the whole trunk of such a nerve, many muscles are excited to contraction ; the contraction so produced, however, is a mere quivering, quite different from the combined and plan-like movements of the muscles of respiration, &c., or those reflex movements which are produced artificially. In these, there is a certain unity and plan, in the others not ; the difference depending on the circum- stance that in the one a regulating principle associates the muscular movements for the attainment of an organic object or purpose ; in the others this does not take place. When the regular and plan-like manner in which the pulsations of a heart removed from the body take place, is compared with the tu- multuous and purposeless quiverings of a diaphragm similarly circumstanced, it is hardly possible to suppose that the two kinds of movement proceed from the same principle. Irritability acted on by the stimulus of the blood, or air, might explain the mere con- traction of the heart; the regular order, how- ever, in which this takes place, implies the existence of a regulating principle ; and a re- gulating principle implies the existence of a regulating apparatus. While the regular movements of the voluntary muscles suddenly cease when the brain and spinal cord are de- stroyed, those of the organic muscles con- tinue,'; and hence their regulating apparatus cannot lie in the brain and spinal cord, and can only, therefore, be situated in the ganglia of the sympathetic. The heart, according to Volkmann, is more flabby after death than it is during life : the intestines, in like manner, are collapsed in the dead body, and appear like so many flat- tened bands ; while in the living body, at least in small animals, they present more the aspect of tubes ; the looseness of the skin and of the scrotum in the dead body is also remarkable, compared with the appearance they present in the living. These differences depend upon a loss of tone. The tone of the involuntary or organic contractile structures '!. does not, however, depend on the brain or spinal cord, inasmuch as it does not cease after these parts have been destroyed, but may continue in the amphibia at least for months thereafter. It depends, according to Volkmann, upon the sympathetic ; and from this he derives another argument in favour of the view that the ac- tivity of the sympathetic or ganglionic nerve- fibres does not depend upon the brain or spinal cord. After division of a motor nerve, the muscles immediately became relaxed, which shows, according to him, 1st, that the tone depends on an active contraction of the muscle ; 2nd, that the mere irritability of the muscle is not alone sufficient for the restoration of this contraction, but also requires an ex- citing cause or motor impulse ; 3rd, that the nerve conveys this motor impulse to the muscle; 4th, that the place where this motor impulse arises or originates is not the nerve itself, but is a central organ. If now, after destruction of the brain and spinal cord, the tone in the organic muscles and many other contractile tissues continues, it follows from this that, besides the brain and spinal cord there must still be another centre from which motor impulses proceed, and this can only be the ganglia of the sympathetic. In regard to this question, so far as our knowledge of the anatomical constitution of the sympathetic extends, the most probable view would seem to be that it is partly inde- pendent, in its action, of the brain and spinal cord, partly dependent. The circumstance that there are present in its branches nume- rous nerve- fibres which are derived from the brain and spinal cord, would appear to indicate that the organs to which such fibres proceed must be to a certain extent influenced by the central masses of the nervous system. From the circumstance, however, that it probably contains*other nerve-fibres which do not arise in the brain and spinal cord, and more particu- larly from the circumstance of gray nervous matter being present in different parts of its extent, it seems not unreasonable to suppose that the influence which it exercises over the parts towhich it is distributed originates, partly at least, not in the brain or spinal cord, but in the gray or ganglionic matter mentioned. If we attribute to the gray matter of the brain or spinal cord a certain property of originating nervous force, it seems unreasonable to deny similar properties to the gray matter occurring in other parts of the nervous system. What- ever properties are possessed by the one, analogous properties are, it is to be expected, possessed by the other. Besides, no other hypothesis which has been proposed to ac- count for the function of the ganglia appears to harmonise so closely with known facts as that which regards them as so many distinct peripherical nervous masses endowed with properties similar to those which are com- monly attributed to a nervous centre. Properties of fibres of sympathetic. Sensory properties. — In regard to the sensory pro- perties of the sympathetic, different statements are made by authors. Bichat, Magendie, Dupuy,* and others, observed that section of the branches of the sympathetic was attended with few or no signs of pain. Dupuy states that he has removed the superior cervical from the horse without the operation appear- ing to call forth any marked expression of pain. Section of the sympathetic cord in the neck may often be performed in the rabbit without any indication of sensibility being given. Haller found, on the other hand, that irritation of the hepatic plexus in the dog gave rise to distinct signs of pain : the same results were also obtained by Meyer from irritation of the solar plexus. When he made incisions into the superior cervical ganglion, he found, contrary to what had been observed by Dupuy, * See Longet. op. cit. torn. ii. SYMPATHETIC NERVE. 459 that clear indications of pain were elicited. From ligature applied to the renal nerves, as well as from the application of chemical or mechanical stimuli to the semilunar ganglia, animals suffered great pain. So, also, Flourens* found that on irritating ,the semi- lunar ganglion in dogs the animals exhibited distinct signs of pain, and the same results were obtained by Brachet f , from irritation of the thoracic ganglia. Frequently, according to Brachet, stimuli, when first applied to a part of the nerve, do not give rise to pain ; after- wards, however, when the part has been ex- posed to the air for some minutes, if irritation be now applied distinct signs of pain are elicited. Longet J, in like manner, found that on irritation of the semilunar ganglia the animal almost invariably exhibited indications of more or less pain being produced. In other animals, where the lumbar ganglia were sub- jected to experiment, he found, like Brachet, that it was only after prolonged irritation that signs of pain were evinced. So, also, accord- ing to Valentin $, when the cavities of the thorax or abdomen are opened as quickly as possible, and pressure applied to the semi- lunar ganglion, to the splanchnics, or to any other branch of the sympathetic, sometimes no signs indicative of sensibility are evinced. When, however, they have been exposed to the air for a short time they generally exhibit these properties in greater or less degree. The severe pain which frequently attends diseases of parts supplied exclusively by the sympa- thetic nerve, also affords still better evidence than can be derived from experiments of the existence of sensory nerve fibres in the sym- pathetic. Different parts of the nerve appear to exhibit the property of sensibility in different degrees. In regard to this point, Valentin jj gives the following as the results of his ex- periments. 1st. The very grey branches which have passed through several ganglia do not, when the stimulus applied to them is slight, give rise to any signs which would indicate that pain was produced. Such branches are those which pass along the mesentery to the intestine ; strong stimuli, however, such as the application of a ligature or of chemical irritants, cause, when applied even to these branches, distinct signs of pain. 2nd. Irritation of the ganglia themselves is followed by signs of pain either immediately or after a short time. 3rd. The connecting cord of the sym- pathetic is similarly circumstanced in regard to sensibility as the ganglia. 4th. The rami communicantes are as highly endowed with sensibility as the posterior roots of the neigh- bouring spinal nerves. He found that section * Rech. Experimental, sur les propr. et les Fonc- tions du System. Xerv. p. 229., as quoted by Longet. t Rech. Experiment, sur les Fonct. du Systeme Xerv. Gangl. 2nd edit, Paris, 1837, p. 3o7., as quoted by Longet. t Op. "cit. ii. p. 566. § Lehrbtich der Physiologic des Menschen, 1844, band ii. p. 421. || Op. cit. band ii. p. 422., as quoted by Longet. of a communicating branch did not destroy the sensibility of the corresponding ganglion : the main cord of the sympathetic must also be divided above and below the ganglion before this ensues. In the lumbar region Brachet* found that, when the communicating branches of three successive ganglia were divided, the central ganglion was deprived of its sensory properties. The greater the number of ganglia intervening between the point of the branches of the sympathetic, to which the irritant is applied, and the cerebro-spinal centres, the less distinctly, according to Valentin, does it give rise to signs of pain. Hence, the peri- pheral branches are the least sensitive, while the rami communicantes are the most highly endowed with this property, the connecting or main cord of the sympathetic and ganglia being intermediate in this respect between these two. The nature of the stimulus ap- plied has also an influence on the results produced : when the ganglia are merely pricked, or their branches quickly divided, sometimes no sign of sensibility is evinced, whereas pressure, application of nitric acid or potash to the same parts give rise to distinct expres- sions of pain. In regard to the experiments which are made with a view to ascertain the sensory properties of this nerve, it is to be observed that in general it is only by application of very powerful stimuli that the phenomena of sensibility are elicited : they seem to act by producing a more or less abnormal condition in the part of the nerve to which they are ap- plied, and hence the effects they produce may be regarded as belonging to the same category as the phenomena observed in diseased con- ditions of the organs supplied by this nerve. In the normal or healthy condition the fibres of the sympathetic seem to be almost entirely destitute of the property of communicating impressions to the sensorium. We do not know, as Volkmann observes, whether the organic muscles be at rest or in motion ; whether the glands secrete in larger or in smaller quantity ; whether the gall-bladder be full or empty. We are sensible of the impres- sions made by the particles of food so long as they remain in the mouth, but, as soon as they reach the stomach or intestinal canal, we are no longer aware of their presence. Motor properties. — That the sympathetic contains motor nerve fibres there can be no doubt ; irritation of its branches being followed by movements in the different muscular organs to which they are distributed. Thus irrita- tion of the splanchnic nerves in the living animal, or immediately after death, is generally followed by more or less extensive contrac- tions in the small intestine. Miiller observed that the same result followed irritation of the semilunar ganglion : the same observation has also been made by Kiirschner.f Mechanical or chemical irritation, but especially galvanic * Op. cit. p. 360., as quoted by Longet. f Abhandlungen ttber das Xerven System, von M. Hall. Aus dem Englischen von D. C. KUrsh- ner, Marburg, 1840, Xachtraege, p. 182. 460 SYMPATHETIC NERVE. stimulus applied to the filaments of the sym- pathetic which pass to the heart, have the effect of accelerating the pulsations of that organ and of exciting it to renewed contrac- tion after it has ceased beating. As move- ments very frequently arise in organs supplied by the sympathetic, especially in the intestines, spontaneously, at least under the stimulus of the atmospheric air, it is sometimes difficult to determine whether the contractions which follow the application of a stimulus to any of the nerves be really caused by this, or whether they may not belong to those just mentioned. Frequently, however, the contraction follows the irritation so regularly as to leave no doubt that the two are connected ; if, moreover, the abdominal muscles in the cat or rabbit be removed, so that the thin and transparent peritoneum alone remains over the viscera, application of mechanical or chemical irritants to the splanchnic nerves in the thorax may still be observed to be followed, in many cases at least, by contractions in the intestine. In such experiments the air is prevented from acting upon the viscera by the intervening peritoneum, and in this way the fallacy above mentioned is less liable to occur. It remains to consider the motor influence of the sympathetic in reference to the different muscular organs supplied by it. Heart. — The heart, as has been already stated, derives its nerves from the sympathetic and pneumogastric. That the branches which are supplied by the sympathetic exercise an influence over the movements of the heart, is shown by what has been already stated, that after it has ceased to beat, irritation of the branches which pass to it from the cervical ganglia will again excite it to contraction. Similar results frequently follow irritation of the ganglia them- selves. When the galvanic stimulus is ap- plied to the cardiac branches of an animal in which the heart has not yet ceased pulsating, the effect is to augment the number of beats, and at the same time to increase their strength. In a rabbit in which the heart's action had ceased, Valentin * found that when the wires of the magneto-electric apparatus were applied, about A of a millimetre distant from each other, upon the second thoracic ganglion of the right side, a very powerful contraction in the auricles immediately ensued : the ex- periment was repeated several times, and with the same result. This also took place when the same stimulus was applied to the first thoracic ganglion. When, on the other hand, the wires were laid upon the aorta at the dis- tance of ^-th of a millimetre from the heart, or upon the surface of the right ventricle, no effect was produced. He concludes, therefore, that the stimulus when applied to the nerves was, in this case, more effectual than when applied to the muscular fibres themselves. As regards the function of those filaments which are sent by the pneumogastric to the heart, E. H. Weber f believes that they exercise a re- * Loc. cit. p. 427. f Wagner's Handworterbuch der Physiologic, band iii., Abtheilung ii. p. 45. straining influence over the movements of the organ ; stimulus applied to the pneumogastric, according to his experiments, having the effect of retarding or altogether stopping its move- ments. When the stimulus of the electro- magnetic rotation apparatus was applied to the bulbus arteriosus in the frog's heart, — the part of the organ around which the fibres derived from the sympathetic are, according to him, chiefly distributed, — he found that the pulsations were increased in number as well as in strength. When, on the other hand, the same stimulus was applied to the upper portion of the inferior vena cava, where the filaments of the pneumogastric are mainly dis- tributed, the effect produced was not an ac- celeration but a retardation or stoppage of the heart's action. When a defined part of the vagus has been stimulated for some time continuously, the heart again begins to pulsate : when a portion of the nerve above this point is now stimulated, no effect is produced; when, on the other hand, the stimulus is ap- plied to a portion further down, nearer the heartj a cessation of its movements is again produced. The circumstance that the heart, after the stimulus has been applied to the pneumogastric for some time, again commences to beat, is attributed by Weber to the part of the nerve becoming exhausted, or losing its restraining influence, when the heart, being thus freed again, begins to pulsate. Budge*, however, attributes the cessation of the movements of the heart, produced by the application of galvanic stimulus to the pneu- mogastric, not to any restraining power ex- ercised by that nerve, but rather to a temporary exhaustion produced by the strength of the stimulus. In support of this view, he states that, although the movements of the iris chiefly depend upon the oculo-motor nerve, yet Weber found, when the wires of the magneto-electric rotation apparatus were applied to this nerve within the cranium, that the pupil became dilated, remaining so for a considerable time after stimulus had been withdrawn, and then again slowly contracting. The effects thus produced upon the iris are, according to him, analogous to those pro- duced upon the heart by application of the galvanic stimulus to the pneumogastric. More- over, the nerves which are sent to the heart of the frog do not present the arrangement which Weber has described. No other fila- ments than those which pass from the vagus are distributed to the heart of this animal, at least no others have been demonstrated. The vagus nerve becomes united with the sympa- thetic in the ganglion, which is situated about one line from the root of the pneumogastric ; and from this ganglion, which contains fibres of the vagus and sympathetic, springs, amongst other branches, a slender filament which is destined for the heart. This runs down- wards on the inner aspect of the lungs, and passes along the veins to the auricles and ventricle, the former receiving the greater number of the nerve fibres. The branch in * Wagner's Handworterbuch, band iii. p. 415. SYMPATHETIC NERVE. 461 question contains fibres derived both from the sympathetic and also from the pneumo- gastric. Again, such a restraining power must hold an opposite relation to the moving power in the normal condition ; the moving power would therefore express itself only in part, according as the other is in a latent state or in a state of activity, and consequently sec- tion of the vagus nerve ought, did it exert the restraining power in question, to be fol- lowed by an acceleration in the movements of the organ, which is not the case. Budge, therefore, seems to regard the fibres which are sent to the heart in the frog by the pneu- mogastric, as possessed of motor and sensory properties. Schift* also found that when the heart's action has been made to cease by application of the wires to the groove between the au- ricles and ventricles, this effect cannot be counteracted by applying them to the bulbus arteriosus. The phenomenon of the cessa- tion of the heart's action, produced by the application of the galvanic stimulus to the pneumogastric, he explains by supposing that its fibres are in a state of activity during the systole of the corresponding part of the heart, but quickly become ex- hausted, thus allowing the diastole to take place: thereafter, their activity being again renewed, a second systole results. When therefore, strong galvanic stimuli are applied to the nerve the state of exhaustion continues longer and in the same proportion the dia- stole, or cessation of the heart's action, is also longer. In accordance with the above views, Valen- tin * in like manner holds that the sympa- thetic has no influence over the movements of the heart in the frog, neither giving rise to acceleration nor stoppage of its action. In regard to the connection between the central masses of the nervous system and the action of the heart, it is evident, from what has been above stated in regard to the effects which are produced by the application of the galvanic stimulus to the pneumogastric nerve, that a certain influence must be exercised by these. By Willis f, and others, it was held that the movements of the heart, as well as of the other inorganic muscles, depend upon the cerebellum. "This they believed from the circumstance that the nerves which preside over the involuntary actions were supposed to take their origin from this part of the ner- vous system, and also from observing that wounds upon the back part of the head proved speedilv fatal. HallerJ, again, endeavoured to show that the action of the heart is en- tirely independent of nervous influence, and is due merely to the inherent irritability of the muscular fibres. From the circumstance that sudden destruction of the spinal cord im- mediately produces an interruption of the heart's action, Legallois concluded that its * Loc. cit. p. 694. f Cerebr. Anatomia Xervorumque Descript. et Usus, p. 195. J Dissertat. sur 1'Irritabilite, t. i. p. 72. movements are not due to inherent irritability, as Haller maintained, but depend upon the spinal cord. The cessation produced in the way just stated, although indicating that an influence may be exercised through the cen- tral nervous masses upon the movements of the heart, by no means implies the conclusion which was drawn from it by Legallois, in- asmuch as the heart may sometimes in such cases again begin to pulsate. That the heart may be influenced in its action through the medium of the central masses of the nervous system is also shown by the effects which are produced by the application of the galvanic stimulus to these parts. Thus, in the frog, as shown by the experiments of Weber*, Budge-j-, Valentin £, and others, it may be made to cease pulsating by applying the wires of the magneto-electric rotation apparatus to either side of the medulla oblongata. Unless there has been much loss of blood in exposing the parts the heart becomes dark-red, and is very much distended; where the large blood- vessels have been previously cut the heart still ceases to pulsate when the stimulus is applied as above : it does not, however, pre- sent the dark-red distended appearance, but is more or less collapsed and pale. The ex- periment, according to them, seldom or never fails. If the electric stimulus has been ap- plied for too long a time the heart again begins to beat, in the same way as takes place when the stimulus is applied to the trunk of the pneumogastric nerve. The same stimulus also sometimes produces more or less change in the rhythm of the organ. According to the Webers, the portion of the central nervous masses which, when stimulated in this man- ner, gives rise to a cessation in the action of the heart, is that extending from the corpora quadrigemina to the posterior extremity of the calamus scriptorius. Budge found, in his experiments, that the corpora quadrigemina were not so intimately concerned in the pro- duction of these effects as the medulla ob- longata. Tiedemann § appears to regard the cerebellum and the medulla oblongata as the parts through which the cessation of the heart's action may be induced, while stimulus applied to the corpora quadrigemina produces no effect. Valentin believes that while the corpora quadrigemina and cerebellum exercise a certain influence, the medulla oblongata is the part chiefly concerned. In nine mice, which were rendered insensible by chloroform, and whose hearts and medulla oblongata were laid bare, Valentin endeavoured to ascertain the parts of the central nervous masses which, when stimulated in the way above mentioned, give rise to cessation of the heart's action, as also the effects which are produced by the same stimulus when applied to the spinal cord. In none of them did he observe any * "Weber, "Wagner's Handwbrterbuch, band iii., 2nd Abtheil, p. 44. f Ibid. p. 415. &c. j Lehrbuch der Physiologic, band ii. p. 464., et seq. § Midler's Archiv. 1847, p. 498. 462 SYMPATHETIC NERVE. stoppage of the heart's action when the cere- bellum, or corpora quadrigemina were the parts to which the stimulus was applied : when applied to the medulla oblongata, on the other hand, this effect was invariably pro- duced. The cervical part of the spinal cord, when stimulated, gave different results. In a mouse, which had been under the influence of the narcotic for 2£ minutes, the heart was repeatedly made to cease pulsating when the wires were applied upon either side of the spinal cord in the region of the third to the fourth cervical vertebra, and also when ap- plied to the part between the first and second cervical vertebras. After repeating this ex- periment several times, and with the same result, he cut the spinal cord across in the region of the second to the third vertebra ; when the stimulus was now applied to the lower cut extremity of the cord the heart's action was accelerated. The cessation produced by application of the stimulus to this part of the spinal cord in the former experiment was, therefore, according to Valentin, probably due to its being transferred along the spinal cord to the medulla oblongata. In two other animals it was found that the two lower thirds of the cervical portion of the cord in like manner gave rise to no cessation in the heart's action, but rather, after the first few seconds, caused it to be accelerated. A young rabbit was strangled, the head se- parated from the body at the articulation between the occipital and first cervical ver- tebrae, and artificial respiration kept up. When the wires of the battery, moderately loaded, were now applied to the upper part of the spinal cord, in the region of the first cervical vertebra, the heart, which was before at rest, commenced pulsating. The spinal cord was laid bare from the first cervical to the eighth thoracic vertebra. When the wires were inserted in the region of the fifth cer- vical to the second thoracic vertebra, the heart's action was distinctly accelerated. When the spinal cord was removed, the same result still followed upon application of the wires, because the roots of the nerves were stimulated. When the heart was cut out of the body, and again placed in situy the above experiment was repeated without effect. Just as stimulus of the sympathetic branches in the mammalia is followed by acceleration of the heart's action, while stimulus of the pneumogastric causes it to cease pulsating, so also Valentin concludes, from the above ex- periments, that stimulus applied to the spinal cord gives rise to the former result, while from stimulus applied to the medulla oblongata the latter result ensues. In the frog, accord- ing to Valentin, the spinal cord has no in- fluence over the movements of the heart. He also holds, as already stated, that in this animal, the sympathetic, in like manner, exer- cises no influence in this respect. In a pigeon, he found that when the wires of the magneto-electric apparatus were inserted into the cerebellum, the heart's action became more or less laborious : when applied to the spinal cord, in the reg'on of the first cervical vertebra, forwards, towards the medulla ob- longata, the heart's action was repeatedly brought to a stand. The cessation in the heart's action by appli- cation of the galvanic stimulus to the medulla oblongata most readily ensues, according to Valentin, when the wires are applied to its sides, or to the under surface in the vicinity of the roots of the eighth pair, and in no in- stance does it ensue when the wires are ap- plied to any part of the central nervous masses after removal of the medulla oblongata. The influence exercised upon the heart's action by the central nervous masses is also shown by the diminution in the number as well as in the strength of its pulsations, which ensues when these are removed, especially on removal of the medulla oblongata. That the diminution in question does not depend en- tirely upon the stoppage of the respiratory process consequent on the destruction of the medulla oblongata, has been shown by Budge. When, in the frog, the anterior portion of the medulla is left, the lungs continue to act ; and yet, according to him, the pulsations of the heart diminish very rapidly both in strength and in frequency. He finds that, although removal of the other parts of the central ner- vous masses produces little immediate effect on the heart's action, it seldom continues for any length of time after the removal of the medulla oblongata. The effects which follow disease of these parts in like manner illustrate the in- fluence which they exercise over the move- ments of the heart. In compression of the brain, as well as from lesion of the upper part of the spinal cord, the pulsations are frequently diminished : the effects of shock in altogether stopping its action also illustrate the same thing. From the experiments above mentioned, Valentin and others hold that the nervous centre upon which the heart's action depends is the medulla oblongata. The particular rhythmical order in which its different parts contract is due, according to some, to pecu- liarities in the manner in which they are acted upon by the blood, the contact of arterial with the lining membrane of the left cavities of the organ, that of venous blood with the lining membrane of those of the opposite side, fur- nishing the proper stimuli, in obedience to which these parts contract. The successive contraction of auricles and ventricles is in like manner explained by the blood first entering the former, and causing them to contract. By their contraction it is propelled into the ven- tricles, and stimulates these to contraction also, while the contraction of the ventricles causes the auricles to become again filled with blood from the veins, and so on indefinitely. This rhythmical order in the movements of the organ has also been attributed to pecu- liarities in the mode of arrangement of its muscular fibres. The muscular fibres of which it is composed, as may be seen on examin- ing with the microscope the auricles in the heart of the frog or other small animal, do not SYMPATHETIC NERVE. 463 lie parallel to one another, as in the ordinary muscles, but cross one another in different di- rections, many of the bundles being at the same time observed to present a more or less branching character. The branches or divi- sions of one bundle cross those of neighbour- ing bundles. In this manner the fibres form a number of reticulated layers laid over one another, while at the same time bundles pass from one layer into the adjacent layers, so that a more or less complete intermixture of the fibres takes place. The fibres composing the ventricles also present more or less of this re- ticulate arrangement. Moreover, many of the fibres of the auricles pass into those of the ventricle, and vice versa. In virtue of such an arrangement of the fibres, stimulus applied to one part of the heart gives rise to a contrac- tion in the bundle to which it is applied : since this crosses neighbouring bundles its con- traction acts as a stimulus to these, in obe- dience to which they also contract. In this manner, the contraction is not limited to the fibre, or bundle of fibres, to which the stimulus is first applied, but extends over the entire mass. So also the contraction of the fibres, which are described as passing bet ween theauri- cles and ventricles, stimulate the fibres of which the latter are composed, giving rise to a ge- neral contraction in them also ; and in this way the successive contraction of auricles and ventricles is produced. According to Schiff, as mentioned by Valentin, the movements of the heart may be reduced to the peri- staltic or vermicular type. He holds that in a certain part of the muscular substance are contained the nerves which preside over the movements of neighbouring bundles. When this contracts, a stimulus is thereby given to the nerves which supply the portion of the muscular substance immediately suc- ceeding ; so that in this manner a number of progressive contractions of the successive bundles of fibres are produced. The contrac- tion of the auricles or ventricles is thus not a single simultaneous act ; but is made up of a great number of contractions succeeding one another, in the same manner as is seen in the contraction of the intestine. It is the rapidity with which they follow one another that gives rise to the appearance of their being simul- taneous. These contractions travel from auricle to ventricle, giving rise to the successive contractions of these parts. He finds that when a ring of the muscular substance at the base of the ventricle in the frog's heart is brought, by local application of the galvanic stimulus, into a state of continued or spas- modic contraction, the due rhythm between the contraction of the auricles and the part of the ventricle below the contracted portion ceases. When a spasmodic contraction is produced in a part of the ventricle by ex- ternal stimulus this part may be irritated without giving rise to any general contraction. He also finds that when a portion of the ventricle of a heart which still retains its ir- ritability, is stimulated, the contraction is sometimes seen to take place in this before it takes place in the other portions ; the stimu- lated portion is also the part which first be- comes relaxed in the diastole of the organ. In opposition to the view above mentioned Volkmann* maintains that the movements of the heart cannot depend upon the central nervous masses. It continues its pulsations after the brain and spinal cord have been removed. When, however, the rhythmical movements of a part depend upon a nervous centre, they cease immediately after the con- nection between these parts and the nervous centre is broken. The rhythmical movements of the muscles of respiration depend upon a nervous centre, the medulla oblongata. So soon as this is destroyed they cease. In like manner the heart, were the medulla oblongata, or any other part of the central masses of the nervous system the centre upon which its movements depend, must also cease pulsating so soon as it is removed from the influence of these. According to the experiments of Bidder, however, already mentioned, frogs may live for six weeks after the spinal cord has been destroyed, the circulation, as seen in the web of the foot, going on as livelily as before, and presenting no difference when compared with that in the healthy animal. So also when the entire central masses of the nervous system are removed the heart still continues its pulsations until the second day. The movements exhibited by the heart, after the central masses of the nervous system have been destroyed, cannot, according to Volkmann, be explained as mere movements of irritation, due to the inherent irritability of the muscular fibres, acted on by the stimulus of the blood or of the atmospheric air. Mere irritability, acted on by the stimulus of the blood, or of the air, cannot explain why both auricles or both ventricles should contract at one and the same time ; and just as little can we in this way explain the suc- cessive contraction of auricles and ventricles. To explain the rhythmical order in which these contractions take place it is necessary to sup- pose that they, like movements of a similar kind, such as those of the respiratory muscles, are regulated by a nervous centre. The fact that the heart's movements continue after it has been removed from the body indicates, moreover, that the centre upon which its movements depend must be contained in the organ itself. It has been already mentioned that in different parts of the heart are found small ganglia. These are believed by Volk- mann to be the centres on which its move- ments depend. These, according to him, act as organs from which the impulse to contrac- tion proceeds : they are also so connected with one another as to act in concert, the impulses proceeding in such directions as to give rise to the regular succession in which the contractions of the different parts take place. The effects produced upon the heart's action by stimuli applied to the central masses of the nervous system, and upon which the * Loc, cit. p. G16. &c. SYMPATHETIC NERVE. view that its movements depend upon these parts is chiefly founded, are explained by Volkmann as taking place by reflex action through the medium of the sympathetic gan- glia. The fibres which pass from the spinal cord to the ganglia stand to the proper sym- pathetic fibres arising in these in the same relation in which the ordinary sensory fibres stand to the motor fibres of the muscles of animal life. A conclusive way of determining whether the movements of the heart, as well as the order in which these take place, depend, or not, upon the ganglia contained in its substance, would be to ascertain whether they still con- tinue after the ganglia have been extirpated. These, however, are so small, and apparently so numerous, as to render such an experiment impossible. That the continuance of these movements after the brain and spinal cord is destroyed, as well as when the heart is re- moved from the body, cannot be attributed to mere irritability of the muscular fibres acted on by the stimulus of the blood or of the atmo- spheric air, but must be connected with nervous influence, is rendered probable by several circumstances, but especially by the observation first made by Henry, and after- wards by Miiller*, that solution of opium or of other narcotic substances, when applied to the outer surface of the heart, does not produce any obvious alteration in its action, whereas when introduced into its cavities so as to be brought into contact with its inner surface, their almost immediate effect is to cause this to cease. Again, when stimulus is applied to one of the ventricles of a heart which has just ceased pulsating, the contraction thereby produced does not commence at the point irritated, as might be expected were the irritability of the muscular fibres alone con- cerned, but in the auricles, and is followed by contraction of the ventricles. Sometimes, indeed, stimulus applied to the ventricles is followed by contraction of the auricles alone. Even when the stimulus is applied to the apex of the organ, the contraction still com- mences in the auricles, and sometimes limits itself to these. The regular order in which its movements take place, so different from those produced in the ordinary muscles by direct application of external stimuli, would imply that the impulse by which they are produced must be conveyed in a certain de- finite direction to the different muscular parts of which the heart is composed ; and this can only be supposed to be effected through the medium of its nerves. The mere arrangement of the muscular fibres of the heart seems in- sufficient to account either for the general contraction of auricles and ventricles or for the order in which these succeed one another. Jf, in the case of the heart, the contraction of a single bundle of the muscular fibres may act as a stimulus to the neighbouring fibres, by which they also are excited to contraction, the same thing ought to take place in the muscles of animal life : the bundles in these, though * Muller's Archiv. 1845, p. 423, et seq. presenting a different arrangement from those in the heart, are, notwithstanding, in as close contact with one another as are the latter, and have equal facility for stimulating the neighbouring bundles to contraction. The dependence of the rhythmical movements of the heart upon a certain arrangement of its nerves, and moreover that there are certain portions of the same from which the stimuli to contraction proceed, is further indicated by the effects, as shown by Volkmann, which follow incisions made into the heart's sub- stance. When a transverse incision is made through the heart, between its auricles and ventricles, the former have been found to continue their contractions much longer than the latter ; and if a longitudinal incision be made gradually proceeding from apex to base, the rhythm is preserved in both portions until the heart has been divided half way; when the incision is continued further, however, the movements of either part become irregular. When the ventricle is divided transversely into two portions, that towards the apex either ceases its contractions immediately or con- tinues the same only for a short time, whereas that which is still in connection with the auricles goes on contracting as before. It has also been observed that in the heart of the frog there is one portion of the septum between the auricles which continues its con- tractions much longer than any other part ; and in this portion the greatest number of the cardiac ganglia and nerves are situated. It was also observed by Kolliker that the trans- verse groove in the frog's heart in like manner exercised a marked influence on its rhythmical contractions ; and here also the ganglionic corpuscles and nerves are very abundant. In young kittens and rabbits also, Valentin has likewise observed that the groove in question affects the movements of the heart very much. The opinion of Volkmann, therefore, that the rhythmic contractions of the heart are connected with a nervous centre, and more- over that this nervous centre is the sympa- thetic ganglia contained in the heart's sub- stance, seems highly probable. At the same time there cannot be the least doubt that an influence may be exercised over these move- ments by the central masses of the nervous system. Intestinal canal. Oesophagus. — The oeso- phagus receives nerve-fibres both from the pneumogastric and sympathetic. The former is, according to Longet*, the source of its sensibility as well as of its motion, while the sympathetic presides over the secretion of the mucus with which its inner surface is lubri- cated. Valentin, however, as mentioned by Longet, found, on irritating the cervical por- tion of the main cord of the sympathetic in the rabbit, that movements were pro- duced in the middle portion of the oeso- phagus ; and contractions were also produced in the thoracic portion of the same tube when the inferior cervical ganglion or either of the first four thoracic ganglia was irritated. * Op. cit. p. 607. SYMPATHETIC NERVE. 4C5 Longet, on repeating the experiments of Valen- tin, failed to observe any contractions, and concludes that Valentin must have irritated the pneumogastric as well as the sympathetic. It is only (according to Longet) when the pneumogastric or spinal nerves are irritated, that such contractions ensue ; and, moreover, section of the eighth pair is attended by com- plete paralysis of the oesophagus. Stomach. — The stomach, like the oesopha- gus, is supplied by branches of the pneumo- gastric and sympathetic. Irritation of the former is almost always followed by con- tractions in this organ. Irritation of the splanchnic nerves, or of the semilunar gan- glion, according to Longet*, produces no such effect. Valentin, on the other hand, found that stimulus applied to the main cord of the sympathetic in the neck, or to the in- ferior thoracic ganglia, in the rabbit, gives rise to contractions in this organ. Voikmannf has also found that when the stimulus of the electro-magnetic rotation apparatus is applied to the thoracic portion of the sympathetic in the cat it gives rise to powerful peristaltic movements in the stomach. He also observed still more lively contractions excited in the stomach of a young dog when the same sti- mulus as in the previous experiment was applied to the sympathetic cord in the thorax, or to the greater or smaller splanchnic nerves before they enter the semilunar ganglion. It would seem, therefore, that, besides the motor filaments which are sent to the stomach by the pneumogastric, it also receives others through the medium of the sympathetic. As regards the movements of the small intestine, &c., it is almost invariably excited to contraction by irritation of the splanchnic nerves or semilunar ganglion. After the movements produced in the intestine by the stimulus of the air, acting upon them when the cavity of the abdomen is laid open, have subsided, contractions extending over the greater part of the gut may still be produced, as was first shown by Miiller, by application of chemical irritants, such as potash, to the solar plexus. According to Valentin, the move- ments produced by irritation of the splanchnic nerves are chiefly confined to the duodenum and upper part of the jejunum, while irritation of the solar plexus, on the other hand, is fol- lowed by contractions which extend over the whole of the small intestine. Irritation of the sympathetic cord in the thorax as high up as the fifth or sixth ganglion, and also in the lum- bar region, gives rise, according to Valentin, to distinct contractions in the small intestine, while stimulus applied to the lumbar and sacral portions acts very energetically upon the great intestine and rectum. The influence of the sympathetic over the movements of the intestines is also shown by the observation of Valentin that when the branches which pass along the mesentery are irritated, con- tractions are produced in the particular por- tions of the intestine to which they are dis- * Op. cit. p. 609. t Mullers Archiv. 1845, p. 414., &c. Supp. tributed, while the rest of the gut remains quite motionless. Budge observed that movements were ex- cited in the coecum of the rabbit when the trunk of the vagus-nerve in the neck was stimulated by means of the electro-magnetic rotation apparatus. As in the case of the heart, so also in regard to the intestinal canal, stimuli applied to the central nervous masses have been ob- served to exercise a greater or less influence in exciting contractions in the intestine. In animals newly killed, Valentin has fre- quently observed movements produced in the intestines by division of the anterior and pos- terior roots of the spinal nerves. In such experiments, however, it is difficult to ascer- tain whether the contraction be due to the stimulus applied to the nerves, or whether it may not be owing to the stimulus of the air acting directly on the intestines them- selves. The application of galvanic stimulus leads to more decisive results. When, ac- cording to Valentin*, the wires of the mag- neto-electric apparatus are applied to the corpora quadrigemina or medulla oblongata, lively contractions are excited in the stomach and intestine. Contractions were also pro- duced in the small intestine, great intestine, and rectum, by application of the same stimulus to the spinal cord. In Cyprinus tinea, Weber has shown that ver}T powerful contractions may be excited in the stomach by application of the wires of the electro- magnetic rotation apparatus to the posterior part of the cerebellum or to the medulla oblongata. The same stimulus applied to the spinal cord in the animal above mentioned, as also in dogs, he observed to be followed by movements in the intestinal canal. From the experiments of Valentin it ap- pears that the movements which are excited in the intestinal canal by stimulus applied to the central masses of the nervous system, are not produced through the medium of the pneumogastric alone. In a rabbit which had been bled to death, and in which the ab- dominal muscles were removed without injuring the peritoneum, he found, when the wires of the magneto-electric apparatus were inserted into the cerebellum, that very lively movements ensued in the small intestine, al- though the two vagi nerves had been pre- viously divided in the neck. Budge, how- ever, finds that it is only when the two vagi nerves have been left that movements can be excited in the coecum of the rabbit by appli- cation of the galvanic stimulus to the medulla oblongata. The constipation and tympanitis which frequently attend diseases of the spinal cord, in like manner indicate that the central masses of the nervous system exercise a cer- tain influence over the movements of the intestinal canal. These movements, however, like those of the heart, still continue after the brain and spinal cord have been destroyed. Bidder, as * Op. cit. p. 466., &c. H II 4C6 SYMPATHETIC NERVE. cited by Volkmann, fed several frogs with worms and immediately destroyed the spinal cord : on opening the animal twenty-four hours afterwards, the stomach was found distended with tough slimy matters : if, on the other hand, forty-eight hours were al- lowed to elapse before the stomach was examined, it was found almost empty, part of the contents having been probably ab- sorbed, while part had passed downwards into the intestinal canal. The continuance of the movements of the intestinal canal after the brain and spinal cord have been removed, would seem to indicate that these are not the immediate centres on which their contractions depend. The contractions which take place may be explained as due to the inherent irritability of the muscular fibres, while their type may be said to be owing to a peculiar arrangement of these, by which the contraction of one bundle acts as a stimulus to the neighbouring bundles, exciting these to contraction also, and in this way giving rise to the vermicular movements of the gut. It seems probable, however, that they are re- gulated by the ganglia of the sympathetic, especially since it has been observed by Henle*, that in pieces of the intestine which have been cutaway close to the line of attach- ment of the mesentery, the contractions pro- duced by application of local stimuli extend but a little way on either side of the point irritated, and are comparatively feeble. When a part of the mesentery is removed along with the portion of the intestine, they are more powerful and more extended, and are most so when the intestine and mesentery are left in their normal relations. Genito - urinary organs. — Contractions of the ureters have been frequently observed by Valentin f to follow irritation of the abdo- minal ganglia of the sympathetic. They pre- sent the same peristaltic character as "those of the intestines, and pass downwards from the kidney towards the bladder. In the bladder contractions are more easilv pro- duced than in the ureters : sometimes shortly after opening the abdominal cavity of an animal newly killed, the bladder contracts so powerfully as to give rise to an expulsion of its contents. Contractions may be excited in it, according to Valentin, by irritation ap- plied to the sympathetic cord in the abdomen or pelvis, or to the lower lumbar and upper sacral ganglia ; the contraction commonly commencing on that side of the bladder on which the nerves have been irritated. The last lumbar and first sacral ganglia are de- scribed by him as having most influence over its movements. In the vas deferens powerful contractions have been observed by Valentin when stimulus was applied to the two last lum- bar ganglia : the rabbit and guinea-pig were the animals on which this experiment was made. In the latter animal the vesiculas semiriales were also excited to contraction by irritation applied to the lower lumbar and upper sacral * Allgemeine Anatomic, p. 724. t Op. cit. p. 4G8. portions of the sympathetic, sometimes so powerful as to expel the contents through the opening of the urethra. Stimulus ap- plied to the same parts in the female gives rise to contractions in the Fallopian tubes. The uterus may, according to the same ob- server, be excited to contraction by stimulus applied to the lower lumbar and upper sacral ganglia, or to the branches given off from these. The contraction in such cases passes downwards from the Fallopian tubes towards the vagina. In regard to the influence of the central parts of the nervous system over the move- ments of these organs, it would appear, from Valentin's experiments, that contractions may be excited in the urinary bladder by stimulus applied to the spinal cord. The ureters are also said to exhibit contractions when the wires of the magneto-electric appa- ratus are brought into contact with the me- dulla oblongata, or with the spinal cord in the cervical or thoracic regions, as also when they are applied to the right optic thalamus. The same also holds true, according to him, regarding the vasa deferentia, Fallopian tubes, and uterus. He has further observed, that often when the stimulus is applied to one side of the central nervous masses, it is the organ on the opposite side which is excited to contraction : thus stimulus applied to the right optic thalamus not unfrequently acts on the ureter of the left side ; in like manner, when the right hemisphere of the cerebellum is the part irritated the contractions some- times take place in the Fallopian tubes or vas deferens of the left side. These organs, however, like those already mentioned, exhibit their usual contractions after they are removed from the influence of the brain and s:pinal cord. The fact that in paraplegic women delivery has taken place, would appear to show that the contractions of the uterus are not dependent upon the cen- tral masses of the nervous system : this is also shown by an experiment of Segalas*, that di- vision of the spinal cord in the lumbar region in the rabbit does not prevent the completion of the labour. Moreover, it would appear, from a series of experiments made by Pro- fessor Simpson of Edinburgh, that the whole process of labour may be completed, although the spinal cord has, in great part, been pre- viously removed. Pupil. — It was long ago ascertained by Pourfour du Petit f, that section of the main cord of the sympathetic in the neck is very quickly followed by contraction of the pupil, besides certain other phenomena. The same experiment has since been made by Molinelli, Dupuy, Reid, Valentin, and others.;}: Molinelli regarded the effect pro- duced upon the pupil not as an immediate effect of the operation, but as an after result ; * Bulettin de 1'Academie de Medicine, torn. ix. p. 1124. t Histoire de 1'Academie, 1727, 1729, Paris, p. 5. et seq, I See Budge, in Vierordt's Archiv. fiir physio- logiscke Heilkunde, 1852, Erganzungs Heft. SYMPATHETIC NERVE. 467 by Dupuy, on the other hand, it was de- scribed as the immediate consequence of the same. Reid found in his experiments that the contraction of the pupil invariably takes place in the dog and cat, but in the rabbit the result is not so constant. Reid also showed that it was not the section of the trunk of the vagus, but that of the sympa- thetic, that was the cause of the contracted state of the pupil. According to Valentin the effects produced differ considerably in different animals : in the dog the pupil be- comes very much contracted : the contraction is not immediate, but ensues within about half a minute after the nerve has been di- vided. Stimulus applied to the nerve still causes the pupil to dilate, but in a few mi- nutes it again contracts, until it is not larger than the head of a pin, and remains so for months. The contracted pupil has generally a circular form ; there are, however, occa- sionally seen particular inequalities in its margin which change from time to time. When belladonna is applied the contracted pupil dilates, but does not reach the size which the sound pupil attains under similar circumstances. When the aqueous humour is tapped the contracted pupil becomes slightly widened, while at the same time it assumes a longish round form. In the sound eye when treated in this way the pupil be- comes diminished in size. Biffi found that slight dilatation of the pupil followed irritation of the ascending or carotid branches of the sympathetic, division of these being also followed by contraction of the pupil, though to a less extent than takes place after division of the sympathetic cord in the neck. Irritation of the superior cervical ganglion gives rise to the greatest dilatation of the pupil; so also when the same is extirpated the contraction of the pupil is very great. A number of researches have recently been made, in regard to this subject, by Budge* and Waller. When the stimulus of the mag- neto-electric apparatus is applied to any part of the sympathetic cord in the neck, dilata- tion of the pupil takes place ; the part of the nerve nearer the chest being, however, less irritable than that higher up. The superior cervical ganglion is not only more susceptible of the stimulus than any other part of the nerve, but the effect produced upon the pupil also lasts longer. The dilatation of the pupil may be produced by the application of the galvanic stimulus to any part of the sympa- thetic, from the inferior cervical ganglion to the ophthalmic ganglion. Irritation of the sympathetic below the inferior cervical gan- glion, however, has no effect upon the pupil. As regards the origin of the fibres in the sympathetic which influence the pupil, they might be supposed to proceed from three sources: — 1st. They might be regarded as prolonged upwards from the thoracic portion of the main cord, the inferior cervical gan- * See Budge, in Vierordt's Archiv. fur physio- logisehe Heilkunde, 1852, Ergliuzungs Heft. glion being an organ interposed to prevent the transmission of stimuli. Against this view, however, there is the circumstance that the fibres still pass through three ganglia before they reach the eye, the superior cervical, Gasserian, and ophthalmic. 2nd. The}' might be supposed to arise in the inferior cervical ganglion, or to be derived from the spinal cord through the medium of the rami communicantes. If they arise in the gan- glion, the section of the sympathetic cord below this, or of the branches which are con- nected with the ganglion, ought not to give rise to any contraction of the pupil, this de- pending, according to Budge, upon the separa- tion of the nerve-fibres from their centre. In a dog which had been put under the influence of chloroform, the inferior cervical ganglion was sought, and the main cord of the sym- pathetic below the ganglion, as well as all the branches in communication with the latter, were divided one by one. Of all these, only one was found which acted on the pupil. Division of this branch sometimes gave rise to as decided contraction of the pupil as division of the sympathetic cord in the neck. In order to ascertain whether the branch in question has its origin in the spinal cord, the following experiment was made. A rabbit was put under the influence of ether, and the sympathetic of the left side divided in the neck ; the spinal column was then opened and the spinal cord cut across in the region of the third dorsal vertebra, and galvanic stimulus applied to the upper cut extremity of the cord ; straightway the pupil of the right side dilated, while that of the left side, on which the sympathetic had been cut, did not vary in the slightest. From further ex- periments it was found that stimulus applied to the spinal cord below the sixth dorsal ver- tebra has no action on the pupil ; above this point, however, and as high up as the fifth cervical vertebra, dilatation was observed on application of stimulus ; the portion of the spinal cord which has most influence on the pupil being that in the region of the first three thoracic vertebrae. As regards the particular fibres in the sym- pathetic on which its sensory and motor en- dowments depend, Volkmann* believes that none of the fine fibres, described by him as sympathetic fibres, are possessed of sensory properties in their normal condition. In support of this view, he states, 1st. That the number of these fibres is greatest in parts which are least sentient, as is the case more or less with all the organs of vegetative life, and especially with the pia and dura mater, and arachnoid, with the periosteum and with the blood-vessels. The circumstance that these parts are so very seldom, and some of them never, the seat of impressions which are transmitted to the sensorium, must, Volk- mann observes, raise a suspicion that the very rich network of nerve-fibres which occurs in them are not possessed of sensory properties, and the results derived from experiments, as * Loc. cit. p. 601. H H 2 468 SYMPATHETIC NERVE. well as from surgical operations, would seem to show that such is the case. The coats of the blood-vessels he considers to be destitute of sensibility, inasmuch as he found that the operation of fixing the haema-dynamometer into them gave rise to no distinct sign of pain. 2nd. As regards the fibres which take their origin from the ganglia, it seems in a high degree probable that they at least cannot convey impressions from the organs which they supply to the sensorium. In order to communicate such impressions they must transfer them to fibres which do not terminate in the ganglia, but are directly or indirectly connected with the sensorium, and are, in short, true sensory fibres. Such a trans- ference in the normal condition does not, ho waver, appear to take place. 3rd. It is not at all probable that fibres, which in ani- mals that have been beheaded, or are under the influence of strychnine, show so little connection with the spinal cord that stimulus applied to them cannot excite any reflex movements in the voluntary muscles, should be in a condition to communicate impressions through the spinal cord to the sensorium. 4th. Division of the cerebro-spinal nerves which supply the integument is followed by loss of sensibility in that part, although the sympathetic fibres passing to the same have been left uninjured. In the frog, a great number of fibres are sent from the sympathetic to the cerebro-spinal nerves, and are along with these distributed in considerable quantity to the integument : if now the nerves in the leg of the frog be divided above the point at which the fibres of the sympathetic join them, so as in this way to leave the continuity of the latter unin- jured, the limb is notwithstanding deprived of sensibility ; the power of exciting reflex action in the muscles of the limb by stimulus applied to the integument being also at the same time destroyed. Division of the fifth nerve, in like manner, is attended by loss of sensibility in all the parts of the face supplied by this nerve ; and no reflex action can be excited by stimulus applied to the eye, tongue, &c., al- though these parts derive fibres from the sympathetic, which are not divided in the operation. Although in the normal condition the fibres in question are not capable of com- municating impressions to the sensorium, they may, however, according to Volkmann, do so in diseased states. In this way the severe pain which is sometimes felt in organs sup- plied by the sympathetic, does not depend so much on cerebro-spinal nerve-fibres as on an altered condition of the ganglionic fibres themselves. The number of cerebro-spinal fibres distributed to such parts is too small to explain it. Severe pain is frequently felt in bones when diseased, although, according to Volkmann, these probably receive none but sympathetic filaments. The circumstance already mentioned, that in experimenting on the sensibility of the ganglia, it has been found that these are frequently incapable of trans- mitting impressions until by frequent irrita- tion they have been brought into a kind of inflammatory condition, also indicates the same thing. All the fibres which are sent from the cerebro-spinal system to the sympathetic, through the medium of the communicating branches, are probably derived, according to Volkmann, from the posterior roots of the spinal nerves alone, and are not therefore possessed of motor properties. They hold the relation of centripetal or afferent fibres to the ganglia of the sympathetic. The motor properties of the sympathetic are therefore considered by him to be due entirely to the fibres which arise in the different ganglia. In regard to those movements which, as already stated, are excited in organs supplied with sympathetic nerves, by irritation of the cen- tral masses of the nervous system, Volkmann holds that the stimuli to contraction in these cases are not transmitted directly to the organs in which the contractions are mani- fested, but are first conveyed by the fibres in the rami communicantes to the ganglia of the sympathetic, where transference to the proper sympathetic fibres takes place. Thus, then, according to Volkmann, the motor properties of the sympathetic are en- tirely due to the proper ganglionic fibres. The painful sensations which are sometimes felt in parts supplied by the sympathetic are due, not so much to fibres of cerebro-spinal origin as to an altered condition of the gan- glionic fibres, while the fibres which are sent to the sympathetic by the cerebro-spinal sys- tem act as afferent or centripetal fibres to the different ganglionic centres, and by means of which a connection is established between the sympathetic and cerebro-spinal systems. According to Valentin, again, both the motor and sensory properties of the sym- pathetic are due entirely to cerebro-spinal fibres. It is generally admitted that the sympa- thetic receives fibres from the anterior as well as from the posterior roots of the cerebro- spinal nerves. The number of these fibres must, moreover, be very considerable, espe- cially in the higher animals ; it would seem probable, therefore, that the motor, and especially the sensory properties of the sym- pathetic are in part due to these fibres. The experiments of Budge and Waller show, al- most beyond a doubt, that, in the case of the iris at least, the motor fibres which pass to it through the medium of the sympathetic are derived from the spinal cord. The circum- stance, however, that the organs supplied by the sympathetic cannot be influenced by the will, and in the normal condition are removed beyond the sphere of sensation, would seem to indicate that the conducting power of these fibres must be modified by the different ganglia through which they pass in some such way as Volkmann supposes. Are the ganglia to be regarded as centres of reflex action? By Valentin*, Longetf, and others, they are denied this property. * Op. cit. p. 697., as quoted by Longet. t Op. cit. p. 578. SYMPATHETIC NERVE. 469 Prochaska* seems to have attributed such properties to the ganglia, inasmuch as he ex- plains the contraction of the heart by sup- posing that the impressions which are made upon the inner surface of the organ are trans- mitted to the ganglia by means ef sensory nerves, and are there transferred to motor nerve-fibres. Grainier -J-, in like manner, holds that the ganglia are centres of reflex action, and moreover that each ganglion pos- sesses a distinct so-called excito-motory sys- tem of nerves. From what has been already stated, it will be observed that Volkmann also holds the view that, in the ganglia, trans- ference of impression from one fibre to another takes place. From his earlier experiments j;, however, he was led to conclude that such was not the case. He found, on applying a stimulus to the surface of the intestines in a newly-killed frog, that a contraction en- sued which was not confined to the part which had been stimulated, but extended for a considerable distance on either side. After destroying the spinal cord, and again applying the stimulus, he now found that the contrac- tion produced was merely local, confining itself to the part irritated. The extended contrac- tion first produced he believed to be due to reflex action, while the limited contraction in the second experiment he regarded as a mere stimulus movement. From the circumstance, moreover,that the former took place while the spinal cord yet remained, and the latter after it \vas destroyed, he concluded that it was thereby proved, — 1st, that the spinal cord is the centre in which the act of reflexion takes place in the movements of the intestine ; and, 2nd, that the ganglia are destitute of such power. Longetj) also states that it is only while the spinal cord remains that contrac- tions extending over large portions of the intestine can be excited by local application of stimuli, the contraction so produced limit- ing itself, after the spinal cord is destroyed, to the point irritated. As was shown by Henle, however, there can be no doubt that move- ments may be excited by application of stimulus to the surface of the intestine after the spinal cord is destroyed, which are as extended as those excited in the same way while it remains. The contractions produced by local stimuli are so similar both before and after the removal of the spinal cord as to leave no doubt that it can have no share therein. The only question is, whether the difference in character between the extended contractions and those which are limited to the point irritated are due to reflex action, or not. By Valentin and others, the extended contraction is explained in the same way as they endeavour to explain that of the heart, by supposing a particular arrangement of the muscular fibres, by means of which the con- traction of one bundle acts as a stimulus to * Opera Minora, t. ii. p. 169., as quoted by Longet. f Observations on the Structure and Functions of the Spinal Cord. j MUller's Archiv. 1838, Einl. Theil. p. 15., &c. § Op. cit. p. 577. the neighbouring bundles, exciting them suc- cessively to contraction. How far this is the case it is difficult to determine ; it seems, however, that the relation of the one bundle of muscular fibres to the neighbouring bundles in the intestine is not so different from what it is in the ordinary muscles as to explain the limited contractions which take place in the latter, and the extended contraction of the former, upon the application of local stimuli. The opinion of Henle*, that they are of a reflex nature, the centres of reflexion being the grey matter of the sympathetic ganglia, seems, therefore, to be the more probable. Kiirschner also adopts the view that the gan- glia are to be regarded as centres of reflex action. On repeating MUller's experiment of irritating the solar ganglion with potash, he observed that the movements thereby pro- duced in the intestines did not commence at a single point, but in several different coils of the intestine at one and the same time. This may, he says, be explained in either of two ways : the stimulus had either affected di- rectly all the motor filaments, by which these different parts of the intestine are supplied, or only a few of them ; and from these few a transference took place, in the ganglion, to the others. The latter he believes to be the true explanation ; for he found it is quite the same, as regards the extent of the movements, whether the irritant is strongly or slightly applied, and whether a finely-pointed rod of potash or a broad surface of the same is em- ployed. The contractions which are excited in the heart by application of local stimuli would seem to indicate more clearly that the ganglia are reflex centres. When a heart has just ceased pulsating application of a stimulus gives rise to a contraction affecting the entire organ, the contraction, too, taking place in the same rhythmical manner in which it takes place during life. After some time, the stimulus, when again applied, gives rise to a contraction which does not affect the entire organ, but only the particular auricle or ven- tricle to which it is applied, and after some time farther the same stimulus gives rise merely to local contractions. The former two seem to be, as Volkmann regards them, movements of reflex action, while the last is a mere stimulus movement. The circumstance that stimulus applied to the ventricles in such a heart gives rise to contractions which com- mence in the auricles, and therefore at a point distant from that to which the irritation has been applied, seems explicable only on the supposition that the impression thereby pro- duced is conveyed to a nervous centre, and here transferred to fibres proceeding to the part in which the contraction commences. The following experiment of Volkmann would also appear to favour the view in ques- tion. He destroyed the spinal cord in a newly beheaded frog, and satisfied himself * Froriep's Xeue Xotizen, band xii. p. 247., as quoted by Kiirschner. H H 3 470 SYMPATHETIC NERVE, that no reflex action could be produced in the voluntary muscles. The heart was then laid bare, and during an interval of 101 minutes its pulsations were counted at fourteen dif- ferent times. Five minutes after destruction of the central organs they numbered 72 per minute ; thirty minutes afterwards they were 48 per minute. After this they were found to average between 45 and 51 per minute. He then crushed with the blow of a hammer one of the hind feet ; and now, during the 104th minute after the spinal cord had been de- stroyed, counted 70 pulsations. Thus, then, two hours after the operation of destroying the spinal cord, we have a sudden increase of 20 beats in the minute, which admits of hardly any other explanation than that given by Volkmann, that it was due to the stimulus ap- plied to the foot being reflected to the nerves of the heart through the ganglia of the sym- pathetic. Influence of the sympathetic on the vegetative processes. — According to some, these pro- cesses go on independently of any influence exercised by the nervous system, while others maintain that the two are more or less in- timately connected. Of the latter some believe that the sympathetic is the only part of the nervous system by which such influence is exercised, while others hold that it exercises no influence in this respect which is not also exercised by the cerebro-spinal system. There can be no doubt that in the plant the processes of nutrition take place without the co-operation of any nervous influence; and in the same way in the embryo of all animals they go on for some time before any trace of nervous tissue has appeared. In the animal after birth, however, they appear to be more or less influenced by the nervous system. This is rendered probable by several circumstances, such as the effects of various powerful mental emotions and of morbid states of the nervous system upon digestion, on the secretion of the saliva, tears, &c. ; the effects of the same upon the heart and capillary vessels. This is also shown by the changes which take place in the nutrition of parts, when the nerves by which they are supplied have been divided, or after lesions of the brain or spinal cord. Thus, as shown by Magendie, section of the fifth nerve is very quickly followed by distension of the blood- vessels and inflammation of the conjunctiva, sclerotic, and other parts of the eye, which may terminate, in the course of two or three weeks, in complete disorganisation of the eyeball. It has also been found that sec- tion of the nerves of a broken limb prevents the due formation of callus. The experi- ments of l)rs. Sharpey and Baly on the salamander also prove that parts are repro- duced much more slowly and less perfectly when the spinal cord has been destroyed to a certain extent than under opposite circum- stances. When wounds are inflicted upoo both limbs of an animal, and the nerves of the one limb are divided while those of the other limb are left entire, it has been found that while a lively inflammation and normal suppuration take place in the wound of the limb the nerves of which have been left en- tire, the wound in the limb whose nerves have been cut scarcely inflames at all, and only a thin unhealthy discharge is formed. Lesions of the spinal cord have also been observed to be followed sometimes by morti- fications of the paralysed limbs, and this with such rapidity as would seem to indicate that they stand to one another in the relation of cause and effect. The tendency to sloughing observed in typhus and other diseases at- tended with great depression of the functions of the nervous system would also seem to indicate connection between the nutritive pro- cesses and the nervous system. It has been already noticed that branches of the sympathetic pass along with the arte- ries in considerable numbers ; some of them being apparently distributed to their coats, while others accompany them into the sub- stance of the different glandular organs. It has also been stated that sympathetic fibres have been observed to join the cerebro-spinal nerves, and to run peripherically with them to the different organs of animal life. From this distribution of the sympathetic, it has been held that it is in a peculiar manner connected with the nutritive processes. That it does exert an influence over the nutritive pro- cesses is seen from the effects which follow division of its branches. In addition to con- traction of the pupil section of the sympa- thetic in the neck has also been observed to be followed by a disturbed state of the cir- culation in the eyeball, giving rise to swelling and inflammation of the cornea, a shrinking of the eyeball, and at the same time to an increase in the lachrymal secretion. In some of the experiments of Dr. John Reid, the in- jected state of the conjunctiva took place in the course of a few minutes after the opera- tion. In a dog, in which he had divided the common trunk of the vagus and sympathetic as high up as possible, Valentin * observed that the secretions of the eye were very much increased, remaining so even after the lapse of several months. The same effects were also observed by him after extirpation of the superior cervical ganglion in the same animal. Dupuy found, on removing the superior cer- vical ganglion of both sides in the horse, that besides the effects above described the opera- tion was followed by an anasarcous condition of the limbs and an eruption on the whole cutaneous surface. Schifff found, when the two upper tho- racic ganglia in the dog or rabbit were re- moved, that the animal did not survive the operation for more than thirty-four hours; the heart, in the meantime, pulsated very quickly and forcibly. On examination after death, the blood-vessels of the pericardium were observed to be distended with blood, * Op. cit. p. 423., as quoted by Longet. f De vi motoria basics encephali, p. 37., as quoted by Valentin. SYMPATHETIC NERVE. 471 while a partly fluid, partly solid exudation surrounded the heart, forming in some parts adhesions between it and the pericardium. From the experiments of Krimer it appears that division of the renal nerves gives rise to changes in the constitution of the urine. According to his observations this fluid, after the nerves have been divided, contains al- bumen as well as the red colouring matter of the blood, these increasing in the same proportion as the normal ingredients diminish in quantity. Similar results were also ob- tained by Brachet* in dividing these nerves. He cut the renal artery and with it the nerves leading to the kidney, and then connected the two extremities of the cut vessel by means of a canula so as to keep up the flow of blood. The fluid which passed off by the urethra contained fibrin and albumen as well as the red colouring matter or hgematine. Analogous experiments were also performed by Miiller and Peipers.f A ligature was applied around the renal vessels of the dog and sheep so tightly as to destroy the nerves, and again relaxed in order to allow the circulation to be re-established. Only in one case did they observe the secretion of urine continue in the kidney, the nerves of which had been de- stroyed, and in this case it contained blood as also hippuric acid. The kidney itself was more or less injected, and rapidly became disorganised. As regards the influence of the sympathetic on the circulation, it has been already stated, that division of the sympathetic in the neck is followed very rapidly by distension of the vessels of the conjunctiva. From experiments lately made by Bernard, it also appears that in the rabbit" the vessels of the ear on the same side in like manner become immediately distended with blood, so that the ear appears quite red, while at the same time its tempe- rature, as well as that of the whole side of the face, rises so considerably, that the dif- ference between it and that of the opposite side is distinctly appreciable to the touch. This experiment 1 have repeated several times. In a rabbit to which ether had been given, the temperature of the two ears rose to about 9.5° F., the vessels at the same time being much distended. The sympathetic was then divided about the middle of the neck : shortly thereafter the temperature of the ear on the side on which the nerve was not divided, sunk to 85°, and its vessels became much less distended. The temperature of the ear on the side on which the nerve had been divided, still continued as high as 95°, its vessels also remained disteiklecl, and were felt pulsating forcibly. On examining the two ears an hour or so afterwards the tempera- ture of that upon the side on which the nerve had been divided, was still felt to be dis- tinctly warmer than the other : its vessels were also still distended, and pulsating for- cibly. How long the effects produced upon * Op. cit. p. 326. •f De Nervorum in Secretiones Actione, p. 26. the temperature and blood-vessels continue I have not been able to ascertain : they are certainly not so permanent as the contraction of the pupil. While this remains contracted for weeks, or even months, no difference in the condition of the two ears can be distin- guished a week or so after the nerve has been divided.* * The elevation of temperature, according to Bernard, begins immediately after the nerve is divided, and is so quickly developed that in a few minutes, in certain circumstances, the difference in temperature of the two sides of the head may rise to 4° or 5° centigrade. This difference of tempera- ture is perfectly appreciable to the hand, but is better determined by introducing a small ther- mometer into the nostril or ear of the animal. Re- moval of the superior cervical ganglion is followed by the same effects as section of the sympathetic cord, only these effects are always more rapid, more intense, and more durable. After section of the sympathetic cord in rabbits the phenomena of ex- cess of sensibility and calorification are scarce!}' observable beyond five to eighteen days, while in dogs they may continue for six weeks or two months. After ablation of the ganglia in these animals the persistance of the phenomena may be regarded as indefinite: in a dog in which the superior cervical ganglion of the left side had been, removed all the phenomena of excess of sensibility and calorification due to that operation were very intense a year and a half after the extirpation of the ganglion, when the animal was sacrificed for other purposes. The temperature of the side of the head on which the operation has been performed is nearly the same as that of the central parts of the body, such as the abdomen, thorax, or rectum; sometimes, however, it is higher, being 40°, while the temperature of the internal parts is 38° to 39°. The increase of temperature is also attended by an increase in the activity of the circulation, as is very distinctly seen in the ear of the rabbit. But in the following days, or even on the day after the operation, the vascular turgescence diminishes considerably, or disappears, while the heat of the face continues to be very well developed. It is found, by passing the bulb of a small thermometer into incisions properly made, that the elevation of temperature observed on the superficial parts of the head extends to the deeper parts as well, and even into the cavity of the cranium and substance of the brain. This is better observed after extirpation of the superior cervical ganglion. The blood itself, which returns from parts so heated, also possesses a higher temperature. The side of the head on •which the temperature has been so raised, presents also a greater resistance to the effects of heat and cold, when the animal is placed in a stove where the ambient heat is greater than that of the body ; while the sound side becomes warmer, the other does not. When placed in a colder medium than its own body, the whole side loses temperature more rapidly than the other. There is also a sort of exaltation of vitality on the side on which the operation has been performed, the involuntary movements continuing longer on this side than in other parts of the body. When the cephalic extremity of the cut sympa- thetic nerve in a dog is galvanised, not only does the pupil become larger, but all the other phe- nomena which followed division of the nerve disap- pear, and the opposite take place ; the pupil becomes larger than that of the opposite side ; the eyeball pro- jects ; the vascularisation disappears ; and the tem- perature sinks below normal. When the galvanisa- tion is stopped, then the phenomena caused by section of the nerve reappear. By Walter and Brown Sequard the elevation of temperature is attributed to an increased afflux of H H 4 472 SYMPATHETIC NERVE. The experiments of Walther on the frog would also indicate that the circulation is more or less influenced by the sympathetic.* When the fibres which are sent by the sym- pathetic to the nerves of the lumbar plexus were divided, he found, on examining the circulation in the web of the foot, that, al- though at first undisturbed, it very soon afterwards increased in rapidity. The ca- pillaries appeared to be dilated, and contained fewer blood corpuscles than corresponded to their calibre ; the increase in their diameter equalled from one sixth to one eighth of the calibre of the vessel. After a time the ra- pidity of the circulation again diminished, and in some parts it became stagnant. Bidder-)-, on the other hand, could not in his experiments satisfy himself that any dila- tation of the capillary vessels took place. Walther, however, has performed the ex- periment so frequently, and so uniformly with the same result, that he regards the dilatation of the capillary vessels as con- stant. There are, moreover, certain experiments made by Valentin which show that the branches of the sympathetic which are dis- tributed to the walls of the blood-vessels, exercise an influence over their contractions. Thus, when stimulus was applied to the tho- racic portion of the sympathetic in the horse, he observed that the thoracic aorta and tho- racic duct diminished in calibre to a much greater extent than could be attributed to blood due to paralysis of the blood vessels. Ber- nard, on the other hand, believes that the phe nomena are not due to the effects of paralysis of the blood vessels, but 'are active ; they are of the same nature as the vascular turgesence which arises in a secreting organ when it passes from a state of repose to an active discharge of function, and resemble the afflux of blood, and increased sensibility around a recent wound or foreign body in the living tex- tures ; phenomena which are not due to mere para- lysis of the arteries. The sympathetic is the only nerve section of which is followed by an exaltation of temperature. [Section of the fifth nerve Bernard found to be fol- lowed by diminution of temperature on the corre- sponding side of the head. When the facial nerve was divided at its exit from the cranium, an eleva- tion of temperature took place on the paralysed side ; this was increased when the sympathetics on the same side were also divided. If the facial was alone divided then, after a feAV days, the tempera- ture returned to an equality on both sides of the face. The calorification produced by section of the facial nerve Bernard attributes to the division of sympathetic fibres which join the nerve during its course through the temporal bone. He also found that when the anterior or posterior roots of the spinal nerves going to form the sacral plexus were divided, the temperature was not increased but diminished. See Monthly Journal of Med. Science, March, 1854. Original paper in Gazette Medicale, Janvier, 1854. Budge finds that removal of the portion of the spinal cord termed by him the ciliospinal region, is attended by an increase of temperature on the cor- responding side of the head in the same manner as •when the sympathetic is divided in the neck. * Muller's Archiv. 1844, p. 448. f Henle and Pfeuffer's Zeitschrift, band iv. p. 353. the mere action of the atmospheric air. In a newly killed young rabbit, in which the part of the vena cava next the heart, as well as the right auricle were pulsating, he found on applying the wires of the magneto-electric apparatus to the right ventricles, that all con- traction in the vessel immediately ceased. Whatever influence the nervous system exercises over the processes of nutrition, it would seem that the sympathetic cannot be regarded as the only nerve concerned : the cerebro-spinal system also appears to share therein. In addition to what has been al- ready stated, p. 470., there are also other facts which favour such a view. Thus Ma- gendie found that, where the spinal cord was divided in the region of the neck, a disor- ganisation of the eyeball followed, similar to that which ensues upon division of the fifth nerve. SchifF* has observed that when the cms cerebri or optic thalamus in the rabbit was cut across, the secretions of the intestinal canal become altered; the excrements are slimy and mingled with blood ; the digestion is interfered with, the animal, towards the end of the first week, losing all appetite for food. After death the mucous membrane of the stomach and bronchi was found to be more or less injected with blood, the former also being softened. Similar appearances were also observed in the upper half of the small intestine. That, moreover, the influence ex- ercised by the sympathetic over these pro- cesses does not differ from that exercised by the cerebro-spinal system, is indicated by the circumstance that several glandular organs, such as the mammary and salivary glands, derive their nerves chiefly from cerebro-spinal nerves. From the experiments of SchifF and others it would appear, however, that the ganglionic system of nerves is more intimately con- nected with these processes than the strictly cerebro-spinal nerves are. Thus, SchifF found, in regard to the fifth nerve, that when it was divided between the brain and Gasserian gan- glion, the destruction of the textures of the eyeball follow more slowly then when it is divided between the ganglion and the eye. In the frog, also, when the lumbar plexus was divided, the animal continued for two or three months without any disturbance being ob- served in the nutrition of the limb ; but when several of the lumbar ganglia were removed, dropsical effusion into the abdominal cavity, and inflammation of the peritoneum, ending in the death of the animal, ensued in the course oftwoweeks.f Axmann £, as quoted by Va- lentin, divided at their roots the nerves which supply the posterior extremity in the frog, but in no instance observed that the opera- tion was followed by any disturbance in the nutritive processes : wounds of the soft tex- tures as well as of the bones healed as rapidly * De vi motoria basios encephali, p. 37., as quoted by Valentin. t Op. cit. p. 37. f T Ganglioruni Systematis Structura pe«iti«ri ejusque Functionibus. Berlin. 1K<1~. »> «MX TEGUMENTARY ORGANS. 473 ES in the sound leg. When he divided the trunk of the lumbar nerves below the spinal ganglia the skin became gradually pale, its pigment cells diminishing to mere points ; the structures softened ; the liver and kidney no longer secreted ; while dropsicaL effusions, containing the elements of the bile and uric ncid, at the same time took place. The blood corpuscles also gradually disappeared. The vessels of the spinal cord and of its mem- branes became very much distended with blood. When the lower portion of the sym- pathetic cord on either side was removed, the blood-vessels of the hind leg and pelvic organs became highly congested ; the contractility of the muscular tissue in the legs and in the pelvic organs disappeared. Blood was ex- travasated into the bladder and rectum, secre- tion of urine ceased, and dropsical effusions took place. The circumstance that section of sensory nerves is followed by derangement in the nutritive processes much more quickly than similar lesions of motor nerves is also ex- plained by Volkmann as due to the fact of the former containing a comparatively larger number of fine or sympathetic fibres. BIBLIOGRAPHY. Willis, Cerebri Anatomia Nervorumque Descriptio, Amster. 1683. Pourfour du Petit, Mem. de 1'Academie, des Sc. de Paris, 1727, p. 3. Bergen, Dissertatio de Nervo inter- costal!, 1731 ; also in Haller, Dissert. Anat. torn. ii. p. 871. Haller, Respic. H. G. Taube, De vera Xervi intercostalis Origine, Getting. 1743. Disput. Anat. torn, ii., et in Opera Minora, torn. i. Huber, Epist. Anat. ad Wigaud, De Xervo intercostali, &c., Getting. 1744. Neubauer, Descript. Anat. Nervo- rum Cardiacorum, Frankfort et Lips, 1772. C. G. Andersch, Frag. Descript. Xerv. Cardiacorum, Lud- \vig Script. Xeurol. vol. ii. Johnstone, Essay on 'the Ganglions, 1771. Haase, Dissertat. de Gangliis Xervorum, Leips. 1772, Iwanoff, De Origine Nervorum intercostalium, Argent. 1780; also in Ludwig, Script. Xeurol, vol. iii. Ludwig, De Plexu- 1ms Xervorum abdominalium atque Xervo intercos- tali Observations, Leips. 1772 ; also in Script. Xeurol. Wrisberg, Observat. Anat. de Xervis Viscer. abdomin. in Ludwig. Script. Xeurol., torn. iv. p. 27. Scarpa, Anat. Annat, lib. L, De Gangliis et Plexu- bus nervorum, Modenae, 1779, in 4to. Tabulae Neuiologicae ad illustrandum Historian! Anat. cardiacorum Xervorum, &c. Paviae, 1794. W. Hun- ter, Anatomical Description of the human Gravid Uterus, and its Contents, London, 1794. Watiher, Tabula? Xervorum thoracis et abdominis, Berlin, 1783, in fol. Gerrardi, De Xervo intercostali, Florence, 1791 ; also in Script. Xeurol, torn. iii. Sommering, De Corporis humani Fabrica, torn. iv. p. 334. Portal, Description du Xerf intercostal dans 1'Homme, Mem. de 1'Institut. Xational, torn. iv. p. 151. Munnicks, Observat. Variae, Groning, 1805. Rail, Ueber die Eigenschaften des Gangliensystems und sein Verhaltniss zum Cerebralsystem, Reil's Archiv. Band. vii. Rudolpki, Einige Bemerkungen iiber den Sympathischen Xerven, Abhandlungen der Berliner Academic, 1818, et 1815-16. Ribes et Ouiiissier, Rech. Anat. et Physio). Mem. de la Socie'te Me'dic. d'Emulation, torn. vii. p. 86. Bock, iiber das Gangliensystem, Abhandlungen iiber das fiinfte Xerven paar, 'Meissen, 1817. Weber, Ana- tomia comparata Xervi sympathici, Lips. 1817. Dapny, Observat. et Experiment, sur 1'Enlivement des Ganglions gutturaux, des Xerfs trisplanch- niques sur des Chevaux, Journ. de Corvisart, 1816, torn, xxxvii. p. 340. Wutzer, De Corporis hu- mani Gangliorum fabrica atque usu Monographia, Berlin, 1817. J. F. Lobstein, De Xevi sympathici Humani fabrica, usu et Morbis, Paris, 1823. L. Hirzel, Dissert, sistens nexus Xervi sympathici cum Xervis cerebralibus, Heidelberg, 1824, 4 to. ; also in Tiedemann and Treviranus Zeilschrift, Band i. p. 197. Langenbeck, Icones Anatom. neurol. fasc. iii., Getting. 1826. Arnold, Dissert, inaug. de Parte cephal. Xervi s}*mpathici in Homine, Heidel- berg, 1826, 8vo. ; also'in Tiedemann und Treviranus, Zeitschrift fur Physiol. Band ii. Arnold, Der Kopftheil des vegetativen Nervensystems beim Menschen in Anat. und Physiol. Hinsicht bearb. Hiedelberg, 1830, 4to. Tiedemann, Tabulae Xervorum Uteri, Heidelberg, 1822. Varrentrapp, Observat. Anatom. de Parte cephalica Nervi sympathici, etc., Franc-fort, 1832. Bidder, Xeurolog. Beobachtungen, mat abbild. Dorpat, 1836. Bracket Funct. du Syst. Xerv. gangl. 1837. Van Deen, Dissert, de Dif- ferentia et nexu inter Xervos vitae Animalis et Or- £anicae, Leyd. 1834. Giltay, De Xervo sympathico, eyd. 183-1. Panizza, Richerche sperimentali sopra i Xervi, littera del Profess. Panizza. al Profess. Bufalini, Pavia, 1834. Remak, Observat. anatom. et micros, de Systematis nervosi Structura, Berlin, 1838, 4to. C. 'Krause, Synopsis Icon, illus. Xervo- rum Systematis Gangliosi in Capite Horn. Hanover, 1839. Bourgery, Mem. sur 1'Extremite ceph. du Grand Sympath. Compt. Rendus, 1845. Valentin, De Functionibus Xervorum cerebralium et Xervi sympathici, Berne, 1839. Kiesselbach, Dissertatio sistens Formationis ac Evolutionis Nervi sympa- thici una cum Descriptione ejusdem Xervi decursus in Animalibus quibusdam Vertebratis, Monachi, 1836. Krause, Synopsis Icone illustrata Nervorum Systematis gangliosi in Capite Hominis, Hanover, 1839. Horn, Reperta quaadam circa Nervi sym- pathici Anatomiam Tabulis quartis lithographicis Illustrata, Wirceburgi, 1839. Robert Lee, the Ana- tomy of the Nerves of the Uterus, London, 1841, with plates ; and on the Ganglia and Nerves of the Heart, Lond. Med. Gaz. Nov. 1846, &c. Jobert, Rech. sur les Nerfs de 1'Uterus, Compt. Rendus, Mai, 1841, p. 882. Bidder und Volkmann, die Selbstandigkeit des sympathischeii Nervensystems, durch Anat. untersuch. nachgewiesen, Leipzig, 1844. 4to. Kolliker, die Selbstandigkeit und Abhangig- keit des sympathischen Nervensystems durch Anat. untersuch, bewiesen, Zurich, 1845, 4to. Bracket, Consid. sur le Syst. nerv. Gangl. Compt. Rendus, de 1'Acad. des Sc. 1845. H. C. Raddiffe, On the Sympathetic Nerve, London, 1846. Snow Beck, On the Structure of the Sympathetic Nerve, and its Connections -with the Spinal Nerves, Phil. Trans. 1846. Robin, On the Ganglia, &c. of the Skate, Compt. Rendus, 1847. R. Wagner, Sympatbischer Nerv. Ganglienstructur, &c., Handworterbuch der Physiologic, Band iii. F. H. Bidder, zur Lehre von dem Verhaltniss der GanglienkorperzudenXerven- fasern, Leipsig, 1847. C. F, Axmann, De Gang- liorum Svstematis Structura penitiori, etc., Berlin, 1847. 4 c. Tab. Wagner, Sympath. Gangl. des Herzens, Handwort. der Phys. Band iii. p. 452. (J. Drunimond.') TEGUMENTARY ORGANS. In en- deavouring to deal with so large a subject as the tegumentary organs of animals, within the limits of an article like the present, it ap- peared advisable not to attempt to enter into minutiae of detail (which indeed fall more properly within the province of those who treat of the special classes), but so far as pos- sible to regard these organs as a system in the sense of Bichat — as a sort of zoological class — whose members, the tegumentary organs of particular animals, are but special modifica- tions of one general plan. In reflecting how this might best be done, however, I was met at the outset by certain difficulties and per- 474 TEOUMENTARY ORGANS. plexities whose solution appears to me to be essential to any philosophical treatment of the subject, and to the consideration of which 1, therefore, propose to devote the following Preliminary Section. § 1 . My first difficulty was to find an answer to the question, — What constitutes a tegu- mentary organ as distinguished from any other? The most obvious definition of an integu- ment or tegumentary organ is, of course, — that which forms the external covering of any animal — viscus, on the other hand, being that which is contained. More strictly, it may be said that the integument constitutes that free surface of an animal which is ex- ternal to the edges of the oral and anal aper- tures, or where the former alone exists, to its edge. Now these definitions are perfectly sufficient so far as surface is concerned ; but suppose we make a section perpendicular to the surface, where does integument cease, and where does viscus begin ? So far as I am aware, no elucidation of this point has hither- to been undertaken, and yet, for want of it, the greatest confusion prevails in the nomen- clature of those organs which constitute the outer wall of the animal frame. Intimately connected with this question, and indeed forming a part of it, is a second. In man and the higher animals, there is an universally recognised distinction of the integument into two portions, — the epidermis and the derma ; and these terms have been extended to all animals. But, if we inquire what constitutes an epidermis, and what a derma, no definite answer is to be met with. It may be said that the derma is vascular, while the epidermis is nonvascular ; or that the epidermis is a simple cellular horny structure, while the derma is complex and fibrous,- but these characters, applicable enough among the higher animals, fail completely with the lower. Thus, in the majority of the Invertebrata, the derma cannot be said to be vascular, while, on the other hand, the epidermis, or its representative, assumes the structure of fibrous tissue, bone, cartilage, dentine, and enamel, — acquires, in fact, the utmost complexity, and, instead of possessing a horny nature, contains chitin, cellulose or calca- reous salts. Following Mr. Bowman, — who, of course, when he wrote his well-known article on " Mucous Membrane," in this Cyclopedia, could not contemplate the new questions to which the progress of ten years would give rise, — many regard that which is external to a " basement membrane " as epidermic, that which is internal to it, as dermic structure. This test, however, fails us where we most want it ; for among the lower animals, and in some integumentary organs among the higher, membranes identical in structure, or rather in htructurelessness, with " basement " mem- branes, may be met with, forming the surface of what are assuredly epidermic organs. I believe that here, as elsewhere, the only ultimate appeal lies to development, both as it occurs in the embryo and as it goes on in the adult. What, in fact, is the first process which takes place in the embryo, when the germinal disc is once formed ? It is a sepa- ration into two layers, by the setting up within the outer portion of the primitive germ of a process of growth independent of that in the inner portion. Where these two areae or planes of growth, as they might be called, meet, the germ readily separates into two portions, the outer of which is the so-called serous layer, the primordial tegumentary system ; while the inner is the mucous layer, the primordial viscus. Of course each of these, while actually integument and intestine, represents potentially a great deal more, — the former, for instance, in the higher animals becoming eventually differentiated into the proper tegumentary system and a great part of the nervous, the muscular, and the vas- cular systems ; but what I wish to direct attention to at this moment, is the fact, that this first differentiation into integument and viscus proceeds from the setting up of two independent lines, or rather planes of growth, in the germinal membranes. In the Hydra and Hydroid Polypes gene- rally, we have the essence of this embryonic state as a persistent condition. If, in fact, the body or almost any organ of one of these animals be examined, it will be found (see Memoir on the Structure of the Medusa?, Phil. Trans. 1849) to be composed of two distinct mem- branes, an inner and an outer (fig. 303. A). The junction between the two is distinctly marked by a clear line, which would elsewhere be called a basement membrane («). External and internal to this, there is a layer of young tissue, consisting of a homogeneous periplast with minute imbedded endoplasts (" nuclei"). As we proceed towards the free surface, we find that a process of vacuolation and cel- lulation takes place in the periplast, until the coarsely cellular appearance with which every one is acquainted is produced. Fig. 303. A, hydra ; b, outer membrane ; c, inner mem- brane. B, young mammal ; b, epidermis ; c, derma. In the Hydra, then, we have the whole thickness of the body divided into two por- tions by a line, on each side of which, inwards and outwards, there is an increasing histo- logical metamorphosis or differentiation. There is a median plane of no differentiation, TEGUMENTARY ORGANS. 475 as it might be termed, external and internal to which, is a zone of indifferent tissue, while, still more remote again, is a zone of meta- morphosed tissue. The absolute structure of the two layers thus produced is very similar*, so much so, that, as is well known, either may perform for a time the function of the other. The distinction between the integument and the mucous membrane in a morphological point of view, however, is as strongly marked as in the most complex animal. The integu- ment, in fact, grows from within outwards — it is endogenous, its youngest portions being internal : the mucous membrane, on the other hand, grows from without inwards — its youngest portion is external, and it is, therefore, exogenous. We have here, I believe, the fundamental, and the only essential distinction, between true integumentary or " epidermic " structures and all others. An integumentary or epidermic organ forms or has formed a part of the external surface, and grows endogenously ; its youngest portion and plane of no differentiation being directed inwards. If, for instance, we compare the young skin of a mammal with the body of the Hydra, we shall find precisely the same planes and zones. Fig. 303. B, represents a perpendicular sec- tion of the integuments of a fcetal lamb 3^ inches long. (A) marks the position of the line of no differentiation separating the epidermis from the derma ; on the outer side of that line lie the close-set endoplasts of the deepest layer (rete) of the epidermis, which are dis- posed somewhat perpendicularly to the sur- face. On the inner side are the less approxi- mated endoplasts of the outer youngest layer of the derma, more or less parallel to the sur- face. From a to b, lies the epidermic area of metamorphosis, the indifferent tissue becoming gradually converted into flattened horny cells. From a to r, on the other hand, is the dermic area of metamorphosis, the indiiferent tissue gradually changing into connective tissue. It will be observed here, that as the whole serous layer of the germ corresponds in struc- ture with the epidermis only, of the fully formed animal, so the whole integument of the Hydra corresponds with what is usually considered as only a portion of the integu- ment— the epidermis — of the mammal. The derma, or true skin of the latter, would not come at all under our present definition of integument, since it has all the morphological characters of the mucous layer of the Hydra, or of the germ ; i. e. its youngest layer is ex- ternal, its growth is exogenous, and the me- tamorphosis of its tissue takes place from within outwards. In fact, in all animals higher than the Hydroid Polypes (possessing therefore a vis- ceral cavity) we find a complication of struc- ture, corresponding with that which is pro- duced in the germ, when the "membrana in- termedia'' divides into its parietal and intes- tinal lamina?. Compared with the Hydroid * Though not, as it is commonly said, identical. Polypes, the higher forms are double animals, and a section of their bodies is, morphologi- cally speaking, like a section of two Hydra?, one contained within the other. Both the intestinal parietes, and those of the body, pre- sent the same distinction into a central plane of no differentiation, from which growth and metamorphosis proceed inward and outward on the two respective surfaces, as that ob- served in the parietes of the Hydra. The formation of this so-called membrana intermedia, in fact, appears to result from a repetition of the process which gave rise to the two primary layers of the germ. The previously central plane of no differentiation is replaced by two others, from which growth and metamorphosis proceed in the same way. The result is, of course, the division of the germ into three layers — a central and two superficial (inner and outer) planes of meta- morphosed tissue — and two planes, whence growth and metamorphosis proceed. It results from all this, that, among the higher animals, the true homologue of the integu- ment of the Hydra is the epidermic layer alone. But it would be exceedinglyinconvenient to change the accepted meaning of " Integu- ment " on this ground ; and, therefore, I shall, throughout the present article, consider as integument — the outermost plane of indif- ferent tissue in the animal body, with its external and internal arece of metamorphosis collectively ; these being simply the expressions of two pro- cesses of growth in opposite directions, and their line of contact. It must not be supposed that this phrase- ology involves any hypothetical views: the fact that' any integumentary organ consists of these three portions will be found to be either distinctly stated or implied by all writers, and is indeed obvious enough on inspection. But though the facts be old enough, this ex- pression of them is unfortunately so new, that I know of no existing terminology by which it can be properly enunciated. The term " Epidermis," ibr instance, at present, though it denotes the important character of the direction of growth to which I refer, implies even more strongly the simple cellular struc- ture of an organ ; so that to speak of " Epi- dermic " bony or fibrous tissue would sound almost contradictory. Again, all these distinc- tions, which have been shown to exist between the two elements of the integument, equally hold good with regard to the mucous mem- branes. Now we have a term " Epithelium " for the epidermic element of the latter ; but there is, as far as I know, none for the ele- ment which corresponds v\ith the derma. Nor have we any word for the boundary line be- tween the endogenous and exogenous areae of growth — the term "basement membrane" expressing only an accidental character of the tissue immediately on one or the other sides of that line. Although with great reluctance, then, I feel compelled to propose two or three new terms, which may have general application, not only to the integumentary organs, but to all other 476 TEGUMENTARY ORGANS, membranes which possess free surfaces and definite directions of growth and meta- morphosis. The boundary line — passing through in- different tissue — between any two such op- posite areae of growth and metamorphosis, I term the Protomorphic line. The whole ex- ternal (free) area of metamorphosis I call the Ecderon ; the entire internal (deep) area of metamorphosis, the Enderon. It will be observed that these definitions rest wholly upon the mode of growth, and leave altogether out of consideration the structure of the resulting tissue. In fact, as I have al- ready said, an extensive study of the integu- mentary organs convinces one at once that mere structure affords no base for homology ; the ecderon, for instance, presenting every variety from the structurelessness of a homo- geneous membrane, as in the Tseniadae, to the complex combination of the so-called enamel, dentine and bone, in the scales of Placoid Fishes. It is, I venture to think, no small evidence in favour of the importance of these consi- derations that they enable us to carry still further the doctrine of the identity of struc- ture of plants and animals sketched by Cas- par Wolff, and developed in our own times by Schwann. If we make a transverse sec- tion of the growing limb of a vertebrate ani- mal, leaving out of consideration, for the moment, the vessels, nerves, and muscles, we observe from the surface inwards, 1st, the ecderonic area of metamorphosis; 2nd, the integumentary protomorphic line ; 3rd, the enderonic area of metamorphosis ; 4th, the periosteal area of metamorphosis ; 5th, the protomorphic line, formed by the indifferent tissue between periosteum and bone ; 6th, the osteal area of metamorphosis, within which lies, 7th, the cartilage resulting from the me- tamorphosis of the tissue of the primitive axis of the limb. Now, if we compare this with the growing shoot of a young exogenous plant, we meet with exactly the same series from without inwards. There is, 1st, the epidermis, which commonly becomes replaced by a cork or peri- dermal layer, just as the primary epidermis over a nail is thrust aside by the subjacent and subsequently-formed horny matter ; or, as the horny " epidermis" of a Skate is pushed aside and replaced by the calcareous placoid spine. Beneath this lies, 2nd, a protomorphic (or cambial} line, from which metamorphosis into periderma goes on outwards, while inwards it passes into, 3rd, the metamorphosed tissue of the mesophloeum. Next to this comes, 4th, the metnmorphic area of the enclophlceum or liber ; within which is, 5th, the proto- morphic line of the cambium, which becomes metamorphosed on its inner surface into, 6th, the wood ; within which lies, 7th, the pith, the result of the metamorphosis of the pri- mitive axis of the shoot. I have endeavoured to render these relations obvious by the diagram (fig. 304.), which may be taken for a section from centre to surface of a foetal limb, or of an exogenous branch, a, outer protomorphic line between epidermis or periderma and mesophloeum in the plant ; Fig. 304. between ecderon and enderon in the animal ; a', inner protomorphic line between liber and wood of plant, between bone and periosteum of animal ; 6, 6', cork and epidermic layers of plant ; cellular epidermis and scale of animal, fish, e.g. ; c, mesophloeum, enderon (derma) ; roduced by the horny conversion of a cel- ular ecderon. The hoof of a foetal lamb was entirely composed of such horny cells. Structure of hairs, spines, and feathers. — In these tegumentary organs, we have to con- sider, first, their own proper structure, and, secondly, that of the sacs in which they are at first wholly, and always partially, enclosed. The shaft of a hair is composed of three distinct structures, an external, the cuticle; a middle, the cortex; and an internal, the medulla. Fig. 315, Hair, Man. A, B, D, E, F, from the nose ; c, from the head. The cuticle (fig. 315. c, D, E) on that por- tion of the shaft which lies within the hair sac, consists of two layers, while only the inner of them remains in the protruded por- tion. Viewed in section, as when a hair is observed in its totality, the cuticular layers form a thin double margin to the shaft, the outer (6) having the appearance of minute rhomboidal cells, joined end to end ; the inner (a) seeming to be composed of close- set fibres arranged parallel to one another, and obliquely to the axis of the hair. If, however, the focus of the microscope be adjusted to the surface of the hair, or if the cuticular layer be detached from the shaft, these rhomboidal cells and parallel striae are found to be the expression of irregular transparent structure- less plates, overlapping one another, and closely united into tough membranes, to which their projecting edges give a striated ap- pearance. No trace of endoplasts is visible in the older of these plates, and the matter of which they are composed is singularly un- changeable, remaining untouched on the ad- dition of strong sulphuric acid, or of caustic potash, which completely dissolve the inner substance of the base of the shaft, and leave the cuticle in the form of a transparent, colour- less, double membrane. In man, the outer layer of the cuticle ceases at the level of the sebaceous glands ; and the edges of the plates of the inner layer lie very closely appressed to the shaft ; in many of the lower animals, however, the plates are at a greater angle to the axis of the hair, and their projecting edges give rise to the most elegant sculpturings of its surface. The cuticle proceeds from the horny meta- morphosis of the two outermost layers of the pulp of the hair. The lowest portion of the bulb of a hair, if viewed in section, presents a sharply defined edge (j%. 315., c), which may occasionally be raised up by reagents as a distinct structureless membrane ; but is normally perfectly continuous with the sub- jacent transparent homogeneous periplast of the pulp, in which lie the ordinary rounded or oval vesicular endoplasts of young indif- ferent tissue. Tracing the margin of the hair upwards, we find, next, that the two most superficial series of these endoplasts (D, a, b) are distinguished from the rest, by being free from that deposit of pigment granules which surrounds the endoplasts of the proper shaft substance ; and these two series are more or less distinctly contained in cavities or cells. The outer series is disposed more parallel, the inner more perpendicular to the surface. Still higher, (E) the cavities of the outer series are larger, and their party walls straight and sharply defined, while the endo- plasts, which were at first plainly visible, dis- appear. In the inner series, both cavities and endoplasts disappear, and the periplast seems to split up into thin parallel horny plates (E), whose edges become more and more strongly marked. Such are the steps in the development of the cuticular layers which may be observed in short thick human hairs, such as those of the nostril. In those of the head, however, and in the hairs of the body of the calf, I have been unable to trace the cuticle into anything but a structureless layer, wrinkled externally, which passed into the superficial structureless layer of the deepest part of the bulb (c). I formerly thought that this indicated an important difference, but it is readily accounted for, if we suppose the process of development to be the same in each case, the endoplasts only disappearing very early in the latter. The main substance of the rest of the shaft of all hairs, and its entirety in some, is com- posed of the cortical tissue. This is a horny hard substance, clear and homogeneous in TEGUMENTARY ORGANS. 497 white hairs, but filled with pigment granules, and moreover having its own special colora- tion in coloured hairs, which may be broken up mechanically, or by the action of strong alkalies and acids, into long, pale, some- times striated fibres, which may or may not present remains of elongated endoplasts. Besides the latter and the pigment granules, a multitude of strise and dots are visible in the cortical substance, which are produced by canals and cavities containing air. The cortical substance results from the metamorphosis of the corresponding portion of the hair bulb. The primarily rounded vesicular endoplasts (fig- 315. A), become greatly elongated and spindle-shaped, without ever, so far as I have been able to observe, becoming surrounded by a distinct cell cavity or wall (fig. 315, B). At the same time pig- ment granules arise in the periplast ; it ac- quires a fibrous appearance, becomes horny, and splits up more and more readily into plates and fibres in the direction of its length. As it attains its perfect structure, rounded and elongated vacuolae, which there is no reason whatever to suppose result from confluent cell cavities, arise in it and become filled with air. In fact, the perfect cortical substance is a sort of rudimentary horny dentine. Lastly, the medullary substance — which at- tains a considerable development in the short thick hairs of man, and in those of the body of many mammals, but is frequently absent, as in the hair of the head of man, and according to Briicke (Reichert's " Bericht," 1849) in the bristles of the pig, the whiskers of the dog, seal, walrus and the long hairs of Myrmeco- phaga jubata — consists of a horny matter like that of the cortex and continuous with it, excavated into polygonal cavities, which fre- quently contain air bubbles and pigment granules. The cavities communicate, and the air may be driven from one into the other.* In the fully formed hair, they contain no remains of endoplasts. The medullary substance, like the cortical, proceeds from the metamorphosis of the indifferent tissue of the pulp, but the process, instead of being one of vacuolation and fibrillation, is essentially one of cellulation. The endoplasts, instead of elongating, remain rounded. Cavities are de- veloped round them, whose partition walls become thick and granular. The cavities then gradually enlarging eventually open into one another, and the endoplasts disappear. The whole structure and mode of develop- ment of this tissue, in fact, show its complete identity with the " pith " of feathers, as we shall see more fully below. The hair sac is an involution of the whole integument, and as such is composed of an enderonic and of an ecderonic portion. The former, which is continuous with the subcu- taneous tissues, when well developed, consists externally of a network of fine elastic fibres, within which is a layer of homogeneous tissue containing endoplasts which are more or less * Griffith, Lond. Med. Gazette, 1848. Sitpp, elongated transversely, and which form the superficial layer of the enderon. Within this is a structureless layer, the commencement of the ecderon, enclosed by which are the re- presentatives of the cellular ecderon, the so- Fig. 316. Diagram illustrative of the position of the different layers of the hair sac in a young hair. a, b, outer rootsheath ; c, fenestrated rootsheath ; d, imperforate rootsheath. called rootsheaths. These are commonly de- scribed as two, the outer (a) and the inner (cy rf); the latter again being composed of two struc- tures, an external, the fenestrated inner root" sheath of Henle, and an internal, which I de- scribed in 1845, and which may be called the Imperforate inner rootsheath. The outer root- sheath, like the others, is thicker above than below, thinning out where it joins the bulb at the bottom of the sac. It consists entirely of tissue resembling that of therete mucosum, and needs no particular description. The fenestrated, inner rootsheath lies in im- mediate contact with the outer rootsheath. It is composed of more or less rounded or polygonal flat plates, with faintly marked boundaries, united by their narrow ends, and leaving spaces between their sides {fig. 315. F). It is very tough and resistant, both to mechanical and chemical action, and no endo- plasts can be seen in its elements. The im- perforate rootsheath (a) is composed of flat thin flexible plates not unlike those of the preced- ing layer ; but they present no intervals, their boundaries are strongly marked, and in the centre of each there is a peculiar, elongated, often more or less dumb-bell-shaped entlo» K K 498 TEGUMENTARY ORGANS. plast. In the human hair sac there are usually only one or two laminae in this layer, but in Rodents there are said to be many. If we examine a hair sac above the level of the bulb, it will be clear that these inner root- sheaths are not generated from the contiguous surface of the external rootsheath, as would at first seem probable. No transitional forms, in fact, are visible in the direction of the transverse diameter of the sac. Traced to- wards the base of the sac, however, it is ob- vious that opposite the lower portion of the bulb the inner layers of the outer rootsheath become metamorphosed into horny cells ; and that of these cells, the inner are converted into the imperforate layer, while the outer un- dergo a more complete cornification, and lose all trace of their primitive endoplasts. The clefts which ultimately exist between these cornified plates are not present in the young state, but are the results of a secondary va- cuolation. They have nothing to do with the disappearance of the endoplasts ; for traces of the latter may be observed in the centre of horny plates, at whose edges the clefts are commencing (fig. 315. F). It would appear, therefore, that the rootsheaths grow like the shaft of the hair itself, not by addition to their surface, but by growth of their deep-seated inner ends. Such is the composition of the growing hair ; but the completely formed hair (see § 2. Morphology) presents very great differences in the minute structure of its inner termina- tion. In the first place, the shaft runs out into an irregularly conical mass, like a worn- out painter's brush. It consists, at its ex- tremity, entirely of cortical substance, and the cornification runs in irregular lines into the indifferent tissue, which occupies the bottom of the hair sac and represents both pulp and outer rootsheath. The inner root- sheaths terminate above this point, in an irre- gularly horny layer, which unites with, and is in a manner reflected into, the cuticle of the shaft, which ceases above its brush-like ex- pansion. Finally, the outer rootsheath in the immediate neighbourhood of the inner, is me- tamorphosed into large horny cells, like those of the cellular ecderon. The development of these from the indifferent tissue of the outer rootsheath, may be very clearly traced. The periplast first becomes enlarged and marked off into definite granular areas around each endoplast, and the limits of each area are metamorphosed into clear horny walls. The cavity which these inclose enlarges, and the endoplast, with its surrounding granular mat- ter, remains attached to one wall, and then eventually disappears, while the cavities en- large, and their walls thicken into clear horny " cells," which may eventually be detached from one another. The whole process of the completion of the root of a hair, then, is simply a return of the diverticulum of the ecderon, — the meta- morphosis of whose elements, so long as the hair was in course of formation, was guided and determined into distinct forms along cer- tain fixed lines, — to its general tendency to undergo the ordinary cellular metamorphosis over its whole surface. With this return to its primitive tendencies, the increase of the hair of course ceases, and sooner or later it is pushed out and falls away. The spines of the Porcupine, of the Hedge- hog, and of the Echidna*, present in their histological,as in their morphological relations, an interesting approximation to feathers. Ex- ternally, they are coated by a cuticle, while the principal mass of their walls consists, at the ends, of a fibrous horny substance ; in the middle, there is added to this a medullary substance composed of polyhedral horny cells. Fig. 317. Feathers of the neck of the common Fowl. A, free edge of pulp ; B, c, medulla and cortex ; D, transverse section of cortex; E, a barb, with barbule partly detached from pulp ; F, cornified cell, from rootsheath; G, horny diaphragms in the quill. The section of the shaft of a fully-formed feather presents exactly these constituents except the cuticle ; the centre is occupied by medullary substance (fig. 317. B, #), composed * See Brocker (Reichert, Bericht. Mull. Archiv. 1849). TEGUMENTARY ORGANS. of a coarsely granular horny substance exca- vated by polygonal cavities of about TTOTJ inch in diameter, frequently if not invariably containing air, which adds to the dark hue (by transmitted light) arising from the granular opacity of the horny matter. At its edges, this tissue passes into the cortical sub- stance, which, in a transverse section (Jig- 317. D) appears as a clear, homogeneous or slightly granular mass, dotted over by minute aper- tures, about T?Tthy?y in. in diameter, and ^J^ in. apart. In a longitudinal section, on the other hand (Jig. 317. c, b), the general mass appears obscurely striated in a longitudinal direction ; and in the place of the circular apertures, we see elongated fissures, some- what narrowed at each extremity, whose transverse sections constituted these aper- tures. The pointed ends of the fissures were continued by a line which could fre- quently be traced into some other fissure above "or below, so that I conceive the fis- sures are in reality more or less complete canals. The qtall of the feather is entirely com- posed of cortical substance ; the barbs have the same structure as the shaft ; the barbules present both cortical and medullary sub- stances in a rudimentary condition. Each barbule in fact (Jig. 317. E, e) exhibits along its axis a series of oval cavities, the remains of cells like those of the medulla, while its lateral portions are composed of striated horny matter like that of the cortex, and are produced into the curved and hooked lateral processes (/). The polygonal cells of the medullary sub- stance are produced from the indifferent tissue of the pulp in exactly the same manner as those of an ordinary horny, cel- lular ecderon from that of the rete mucosum ; that is to say, the periplast increases, and becomes marked out into polygonal areae ; it then acquires a horny consistence, and a stronger and stronger definition along the lines of demarcation, until polygonal "cells" (as in Jig. 317. B, a) are formed. The walls of the latter now thicken and become granular; the endoplasts disappear, and at length no- thing is left but the honey-combed perfect me- dullary substance. The mode of formation of the cortical substance is the inverse of this. On examining the line of junction (fig. 317. B) of the pulp (c) with recently formed cor- tical substance (b), it is observable that the endoplasts do not become surrounded by cell cavities, but that the periplast acquires a granular, longitudinally fibrous, appearance; while the endoplasts, though they are oc- casionally visible in the striated mass, soon completely disappear.* The elongated ca- vities or tubuli do not at first exist in the cortex, but are the result of a secondary va- cuolation, and so far as I have been able to observe, have no relation with the pre-existing endoplasts. In fact, these canals, like those in the hair-shaft, the clefts in the fenes- * Compare Schwann, Untersuchungen, &c. trated rootsheath, and the canaliculi of bone, must be regarded as the results of a second- ary vacuolation. The feather sac resembles that of the hair in all essential points of struc- ture, except that the relations of the layers of the inner rootsheath are different. As in the hair, two layers may be distinguished in the inner rootsheath, an outer, strong, dark, horny membrane corresponding with the fe- nestrated membrane, and an inner delicate flexible layer, corresponding with the inner horny rootsheath. The former has a structure intermediate between that of the two layers of the inner rootsheath in the hair, consisting of irregular polygonal plates, which retain the remains of their endoplasts (Jig. 317. p),as in the inner layer of the horny rootsheath, and do not become separated by fissures; while they resemble the plates of the outer horny rootsheath in their thickness, complete cor- nification and striated appearance. The inner layer of the horny rootsheath is a delicate, often granular membrane, which closely invests the outer surface of the feather, and from presenting a cast of its elevations and depressions, has been called the outer " striated jnembrane" of the feather sac (supra, § 2.) It is a sheet of horny matter, in which traces of closely-set endoplasts are discover- able. The inner (Jig. 317. E, d) " striated membrane " is a membrane having a similar structure, possessing similar relations to the inner surface of the feather, and which is con- tinuous with the so-called "pith" in the quill of a fully formed feather. The mode of de- velopment of these rootsheaths is identical with that of those in the hair, and therefore requires no further elucidation here. Tegumentary glands. — The other con- versionary productions of the ecderon which we have to consider, are the glandular ap- pendages, which are always diverticula of the cellular ecderon inwards.* Under this head I include only those small glandular organs which, so far as we know, have no reference to any other functions than that of cutaneous transpiration or fatty secretion, referring to the articles on special divisions of the animal kingdom for an account of those organs, such as the " water vessels " of Echinoderms and Trematoda, the nidamental glands of Mollusks, the genital glands of Vertebrata and Insecta, which might strictly be regarded as productions of the integument. Tegumentary glands in this limited sense are somewhat rare among the Invertebrata. They have, however, been observed in the Annelids, where they consist of delicate tubes, terminating internally by a blind extremity containing a single nucleated cell. Such glands exist on the ventral surface of the head and foot discs in Piscicola, and are scattered all over the body in Clepsine and Nephelis. Similar glands are found opening upon the ventral surface of Argulus foliaceus. * Unless, indeed, these simple " mucous cells," described by Clark and Leydig in Fishes, and which are merely modified cells of the cellular ecderon, should be regarded as glands. K K 2 500 TEGUMENTARY ORGANS. Simple coecal glands are scattered over the whole surface of the body of the Procession Caterpillars, opening at the points of the hairs ; on the sides of the body in Myriapods. on the joints of the legs in Beetles and Bugs. In Mollusca a peculiar, probably glandular, canal exists in the foot of certain Lamelli- branchs, and glandular coeca have been ob- served in the lower surface of the foot in Paludina. A ciliated canal runs in the foot of Pulmonata, and receives glands on each side. The existence of cutaneous glands in the Cephalopods appears doubtful — at least, H. Miiller could only find them as shell glands in the expanded arms of Argonauta. Among the Vertebrata, Fishes, Ophidia, Chelonia and Birds, appear to possess no proper cutaneous glands * ; in Sauria they attain a very slight and local, but in Batrachia and Mammalia, an immense de- velopment. In the frog, the whole surface Fig. 318. The cutaneous glands of the Frog. A, section ; B, superficial view. of the ecderon is beset with minute trifid apertures, so disposed between three epi- dermic cells, as to present a singular resem- blance to the stomata of plants (Jig. 318. B). These lead directly into spherical sacs (fig. 318. A. d.), which are lined by a continuation of the cellular ecderon, and lie in the superficial * Dr. Clark, in his excellent account of the skin of the eel (Trans. Mic. Soc. 1849), describes cuta- neous glands in that animal. The so-called " glands " of the lateral line, however, have since been shown by Leydig to have a very different structure ; and I confess I have not been able to convince myself of the existence of the other glands described'by Dr. Clark. I can find nothing like them, except the strong perpendicular semi-elastic bands, which tra- verse and unite the bundles of connective tissue in this as in other fishes. part of the enderon above its stratified layer (Jig. 318. A. g.) (vide infra). Nerves (/) and vessels penetrate the latter to reach the superficial layer of the enderon, and ramify among these close-set glandular sacs. The sacs usually contain only a clear fluid * ; they are contractile, and may be made to expel their contents by irritation of the nerves dis- tributed to them.f In Mammals, we meet with two kinds of cutaneous glands, sebaceous and sudoriparous. The former are almost invariably developed in connection with the hair sacs, consisting in fact of diverticula of the Malpighian layer of the cellular ecderon of the upper portion of these sacs, whence their position is always superficial. The innermost cells of the solid process become filled with fat — break down, and pour their contents into the hair sac itself, by whose aperture they make their exit. Sometimes, as in the hairs of the head in man and in the pig's bristles, the sebaceous glands are very small and simple, while in other lo- calities they throw out processes, and assume the appearance of complex racemose glands, disposed like rosettes around the hair-sac, from which they are developed. Sudoriparous glands. — These glands, like those just described, are, as Gurlt pointed out, simple, elongated processes of the deep layer of the ecderon, differing from the sebaceous glands chiefly in producing a clear fluid, instead of a fatty secretion. As Kolliker has shown, however, no line of demarcation is to be drawn on this ground, the secretion of the axillary sudoriparous glands in man being an essentially sebaceous substance. The sudoriparous glands are cylindrical coecal tubes varying, in man, from TOO to -s&o °f an mcn m diameter, whose walls are either thick or thin. In the former case they consist of a simple ecderonic cellular coat, contained within a prolonged sheath, formed by the uppermost layer of the enderon, and, like it, composed of a homogeneous or indistinctly fibrillated periplast, with imbedded endoplasts. Outside this, or rather forming part of it, is a layer of longitudinally-disposed smooth mus- cles, and the whole is coated, like the deep sur- face of the rest of the enderon, by a more or less distinct layer of connective tissue. In the thin-coated glands the muscular layer is absent, but the cellular ecderonic coat is fre- quently so thick that they possess no cavity at all. The thick-walled glands are met with in man in the axilla, scrotum, anal region, &c. ; while those of the rest of the body are al- most entirely of the thin- walled description. The glands terminate superiorly in undu- lating canals, which reach the surface of the enderon, and are continued to that of the ecderon by oblique channels excavated in its substance between its cells. Inferiorly, they form close coils, which lie in the subcutaneous * Stated by Bergmann and Leuckart to have an irritating property in Triton. t Ascherson : *Haut-driisen d. Frosche, Miiller's Arrhiv, 1841. Czermak : Haut-nerven d. Frosche Ibid. 1849. TEGUMENTRAY ORGANS. 501 areolar tissue, and receive twigs from the vessels in their neighbourhood. In the other Mammalia, the general structure of the sudoriparous glands is as in man. In the sheep, according to Gurlt,they present the same coiled arrangement, while in the ox and dog they are straight and simple. In the ox they have rounded, d.lated extremities, and are everywhere similar in shape and size. On the hairy parts of the body of the dog, they are small simple coeca, which are very difficult to discover ; while on the ball of the foot of this animal they are very large and resemble those of man. Very large sudoriparous glands have likewise been observed upon the horse's prepuce. Scales of fishes. — In the Ganoid fishes Ac- clpenser and Polyptertu the substance of the scales is composed of ordinary bone whose superficial layer is only denser than the rest, and exhibits a local developement of fine branching tubuli ; but in other fishes, two, if not three, distinct layers are usually distin- guishable in the scales. In many Plagiostomes, for instance, the placoid scales have the same composition as the teeth, consisting of a superficial layer of nearly structureless dense " enamel," or as Prof. Williamson more conveniently terms it, " Ganoin," while the deeper substance is composed of a tissue in every respect similar to dentine, whose innermost portion in some cases passes into true bone, — an addition which might be compared to that of the cement in the teeth. Leydig, indeed, has shown that the resemblances between the scales and the teeth of Placoid fish extend even to their mode of developement. If the pulp contained in the central cavity of the spine-like scale of a Raia clavata be pulled out, globular calcareous masses of TQ^ of an inch and upwards in diameter, and either solitary or adhering together in masses, will be found to be attached to its surface. " These globules are exactly analogous to the dentine globules described by Ozermak, which in human teeth afford the formative material for the matrix of the dentine. What, however, ap- peared to me especially worthy of notice was the circumstance, that the most distinct and beautifully branched canals, having exactly the same appearance as those in the substance of the spine, were already visible in these isolated calcareous bodies, and on carefully examining the fine processes of the canals, no doubt could exist that they were only interspaces or gaps. On carefully adjusting the focus, in fact, it was obvious that one of these large calcareous globules is itself only an agglomeration of many smaller globules, and it could be observed that the gaps left between the latter became the fine processes of the tubules. From these facts, I believe that the correct mode of conceiving the growth of the substance of the spine is, to suppose that the calcareous matter is excreted from the vessels of the pulp, and then in all probability combined with organic matter, runs into smaller masses ; these unite together into larger ones, and become applied to the inner surface of the central cavity, coalescing, and thus adding to the thickness of the spine. Between the calcareous globules, however, canalicular gaps or tubules' remain, which form a connected network and communicate with those branched cavities which already exist in the spine. The scales of the Sharks and the dermal spines of the Rays, then, (and I would draw particular attention to this result,) are per- fectly identical in structure with the teeth, even to the absence of nerves in the pulp, and must be united in the same structural group. I have already (On the Skin of Fresh- water Fishes, Zeitschrift fiir Wiss. Zool. B. iii. H. 4.) pointed out the close affinity be- tween the scales of a number of osseous fishes and their teeth : and scales likewise present globules of calcareous matter, which become fused together to form the homo- geneous substance of the scale. A process, corresponding with that which occurs at the surface of the pulp in the teeth and cutaneous spines, here takes place from the surface of the sac of the scale (Schuppentasche). The scales of osseous fishes, the spines of the Rays, and the scales of the Sharks, therefore, all belong to the series of dental structures, which in no respect interferes with the en- trance of true bony tissue (like the " cement " in the higher animals) into their composition, as we find to be the case in the scales of the Ganoids (Miiller), and in the truly bony semi- canals which are attached to the scales of the lateral lines of many fishes." * For the details of the various modes in which Ganoin, true osseous tissue, and those va- rieties of tubular, more or Jess dentine-like tissues, to which Prof. WilliamsoiP has given the names of " Lepidine and Kosmine," are combined together in the scales of Ganoid and Placoid fish, I must refer to that gentle- man's memoirs, already so often cited. In the Ctenoid and Cycloid fishes there is a superficial " Ganoin " layer, composed of numerous thin structureless calcified laminae, which are frequently thrown into folds, papillae or spines. The deeper substance of the scale is composed of a series of layers of a mem- branous substance, each layer being composed of parallel fibres which take a different direc- tion from those of the superficial and subse- quent layers, so that the fibres of alternate layers cross diagonally. No endoplasts or cells are ever distinguishable among the fibres. In the deepest part of the scale these layers are entirely membranous ; but in passing to- wards the surface, minute lenticular masses of calcareous matter make their appearance in the membranous substance. As Prof. Williamson justly states, these lenticular bodies are not developed between the membranous fibres and lamellae, but in them : " they com- mence as a small calcareous atom, and in-. * Leydig : Rochen und Haie, 1852, K K 3 502 TEGUMENTARY ORGANS. crease in size by the external addition of new concentric lamina?; the direction of the latter not beingparallel with, or having any reference to, that of the laminae of fibrous membrane with which they so amalgamate; thus they are not depositions from, but growths in the membrane ; which growths, as they increase in size, retain their primitive tendency to assume a lenticular form." Following the layers of the scale outwards, these isolated calcareous deposits not only enlarge, but ultimately become fused together, forming at length either a continuous calcareous mass in each layer, or presenting fissures which in some cases traverse the original lenticular calcareous deposits, in others are interstitial to them. I think one cannot but be struck with the complete analogy between the struc- ture and mode of developement here described and those which I have previously shown to obtain in the calcified tegumentary organs of the Mollusca and Crustacea. The ganoin layer corresponds very closely with the " epi- dermis " of the shell or test ; the middle laminated calcified substance is formed by the fusion of concentrically laminated concretions deposited in a membranous matrix in the Fish, the Mollusk, and the Crustacean alike ; while the deep uncalcified layers of the scale are represented by the " horny " laminae which have escaped calcification in Haliotis or Unio, and still more closely by the fibrillated un- calcified layers of the Crustacean test. Structure of the enderon. — The enderon of the Invertebrata is usually entirely composed of rudimentary connective tissue or of mere indifferent tissue, consisting, in the latter case, simply of a matrix with imbedded endoplasts, while in the former it is produced into plates and bands, never exhibiting, however, the pe- culiar bundles and elastic fibres which are met with in fully formed connective tissue. In Paludina, according to Leydig, the pig- ment masses, which lie on the surface of the ecderon, are connected by " clear large cells, with a small parietal nucleus." From their occurrence, wherever in the higher animals connective tissue is found, Leydig calls them '* Binde-substanz-zellen " — " Connective tissue cells ; " but, as he himself points out, they fre- quently contain carbonate of lime, and their relation is rather, like that of the similar cells in Piscicola, to fat. A wonderful complication of structure is attained by the skin of the Cephalopoda. Ac- cording to H. Miiller *, who has recently made some careful investigations on this subject, there lie beneath the cellular ecderon in these ani- mals : 1st, a fibrous layer, usually colourless, but occasionally white and glittering. 2nd, the layer with the chromatophora (vide inf.). 3rd, beneath these a peculiar layer, which gives rise to the colours produced by interference, the metallic lustre, and intense whiteness of many localities. It consists frequently of regular plates, which evidently proceed from nucleated cells. 4th, deeper still lie the larger bundles * Bericht, &c. Zeitschrift fur Wiss. Zoologic. 1853. of connective tissue, the muscles and the vessels. In the Vertebrata, the superficial layer of the enderon is similarly composed of indifferent tissue, and of rudimentary connective tissue ; the former passing gradually into the latter, as Fig. 319. j^ Enderon of the Skate. we trace it inwards, developing its elastic ele- ment to a greater or less extent, and acquiring a more or less distinctly fascicular arrangement of its collagenous element. In the higher Vertebrata, these bundles are usually disposed as an irregularly felted mass ; but in Fishes and Batrachia, they form regularly super- imposed horizontal strata, tied together by perpendicular columns, which penetrate the interspaces of the bundles, and spread out into the irregular connective tissue on the deep and superficial surfaces of the stratified mass (fig. 319. A). On the addition of acetic acid, it is seen that the boundaries of the strata are formed by irregular bands of elastic tissue, in which the remains of the primitive endo- plasts may be seen (as in fibro-cartilage), whose strongest fibres are horizontal, though they send out others irregularly in all direc- tions. The perpendicular columns are likewise composed of bundles of pale elastic fibres (fig. 319.B), and if the intersection of the horizontal with the vertical divisions be carefully examined, it is seen that the former are, as it were, given off by the latter, which thus gradually break up and thin out, terminating above and below in the elastic fibres of the unstratified super- ficial and deep layers. A horizontal section of this portion of the enderon presents a very peculiar appearance, the transparent vertical columns looking like radiating spaces, as which they were, in fact, at first described. Pigment of the enderon. — The enderon presents scattered masses of pigment, some- times contained in cells and sometimes free, in many Invertebrata (Annelids, Trematoda, Echinoderms, Crustacea, Mollusca). In other Invertebrata and in the higher Verte- brata, the pigment is confined to the ecderon. In Fishes and Reptiles, however, a well- marked layer of pigment lies at the surface of the enderon in the form of scattered granules TEGUMENTARY ORGANS. 503 and of irregular more or less stellate masses which are not enclosed in cells. The silvery lustre of the skin of fishes is due to minute rods which constitute a layer at this surface, and should probably be regarded as a peculiar form of pigment granules. In the Cephalopoda and some Gasteropoda among the Invertebrata, the integument undergoes during life the most extraordinary variations of colour, becoming overspread with successive clouds of the most vivid hues. These are produced by the contraction and expansion of peculiar sacs — the chromato- phora — containing masses of pigment granules. According to H. Mutter, (whose observations I have recently had the opportunity of re- peating,) these are sacs attached to whose walls are contractile fibre cells arranged ra- dially, and frequently anastomosing with those of other cells. They do not always contain pigment, but frequently present a distinct nu- cleus. Several layers of these chromatophora of different colours are frequently disposed, one over the other, in a given portion of the skin, and produce by their different states of contraction, relatively to one another, suc- cessive changes in the colour of the spot. Among the Vertebrata the Chameleon, as is well known, presents similar phenomena. Papilla of the enderon. — The enderon is frequently produced into conical or cylin- drical processes, which either merely contain a vascular loop, or are supplied, in addition, with special nerves. In the Invertebrata, we find, in the processes of the mantle into the shell of the Brachiopoda described by Dr. Carpenter, organs which, I have no doubt, must be regarded, like the corresponding pro- cesses in the Ascidians, as vascular papillae. Among the Articulata like processes extend, in the Crustacea, through the whole thickness of the integument to its surface, giving rise to the colourless spots observable on the shell of the crab, for instance. I imagine, however, that these spots were usually occupied by a hair when the shell was thin. In the Mollusca, the marginal processes of the mantle of the Lamellibranchs and Gasteropods, the papillae of Onchidium, &c. and those of Tremoctopus (H. Muller) are very probably both vascular and nervous papillae like those of fishes. Among the Vertebrata, fishes present large projecting papilke, particularly about the region of the lips and operculum, which are both vas- cular and nervous. Simple papillae (nervous?) are scattered over the surface of the body in Plagiostomes and some Ganoid fishes. I am not aware that papillae have hitherto been observed on the integument of Birds and Reptiles. In most Mammals, they are very small, if they exist at all, upon the general sur- face of the body, attaining a considerable size only in such organs as the ball of the foot (Cat, Dog), or on the muzzle. The Cetacea, however, appear to make a remarkable excep- tion to this rule ; it is stated (Heusinger, Breschet, and Roussel de Vauzeme) that the very thick integument of these animals is tra- versed by vascular and nervous papillae, four or five lines long, which extend as far as the outer horizontal horny layer of the ecderon, so that a horizontal section of the ecderon is like that of a horse's hoof. In man, again, the papillae are, as is well known, so abundant as to have given rise to the term pars papUlaris, for the superficial layer of the ecderon. The structure of those which appear to possess special nervous functions will be considered below. Sensory appendages of the enderon. — Very little is known of the ultimate distribution of the nerves to the integument in the Inverte- brata, but we are indebted to Ley dig for showing that in certain Crustacea, Insecta, and Mollusca, it is very similar to what occurs in the vertebrate classes. Thus in Argulus fotiaceus the peripheral nerves become pale, and divide, and at the point of division there is a * nucleus ' as in the embryonic fibres of the frog. In Artemia salina, Branchipus stagnalis, and in the Heteropod Mollusk Carinaria, the termination of the tegumentary nerves is es- sentially similar. The larva of the Dipterous insect Corethra, presents even peculiar sensory appendages, in the delicate plumed hairs which beset the sides of the body. These are articulated in the ordinary way, and have an internal ligament, a sort of spring, attached to their base, which is enlarged and receives the enlarged and cellaeform termination of a nervous twig. It will be obvious that this arrangement is peculiarly fitted for commu- nicating the slightest vibration to the nerves. In the Vertebrata (fishes, reptiles, man), the ordinary mode of termination of the integumentary nerves is in one or two plexuses, whence the fine terminal branches proceed, and end by dividing into minute branches indistinguishable from the imperfect elastic fibrils of the enderonic tissue. Loops have also been observed, but it is impossible to say whether, in any case, these are real ter- minations or not. Gerber and Kolliker have also described " nerve coils" in animals, and in the conjunctiva and lips of man. The simplest form of sensory appendage in the Vertebrata is presented by the large papillae of fishes, into which a bundle of nerve fibres enters, some of which terminate in the papillae, while others, whose looped bands may be readily distinguished, probably pass out again. In certain fresh-water fishes (Barbus, Leu- ciscus), Leydig has described papillae of this kind, which have a cup-shaped depression at their extremities, lodging a globular mass of what he describes as modified epithelium. Special modifications of the tissue of the papillae for sensory purposes in the fingers, tongue, lips, &c. of man have lately been dis- covered by Meissner and Wagner, and de- scribed by them, under the denomination of the Corpuscula tactus. Kolliker, who doubts their special relation to the tactile function, on the other hand, prefers to call these bodies, axile corpuscles. They are simply ovoid masses of im- K K 4 504 TEGUMENTARY ORGANS. perfect connective tissue occupying the centre of the papillae, and further distinguished by having their endoplasts and imperfect elastic Fig. 320. A papilla with its Corpusculum tactus surrounded by three vascular papillae. fibrils arranged transversely to the axis of the papilla, so that they appear to be made up of transverse superimposed laminae (fig. 320.). One or two dark- contoured nerve tubules come up through the base of the papilla, and running along one side of the corpuscles, thin out and terminate, without, so far as I have been able to see, entering its substance. In fact, these nerve tubules are, as Kolliker pointed out, accompanied by a delicate neurilemma, and the axile corpuscle itself appears to me to be nothing more than the enlarged end of this neurilemma. In Birds, a large proportion of the tegumen- tary nerves terminate in bodies which are, on the one hand, related to these axile corpuscles, and on the other to the well-known Pacinian bodies (fig. 322). They are, in fact, usually described under the latter name; but their small size and superficial position, the paucity of their concentric lamellae, and the transverse striation of the solid central axis, ally them closely with the corpuscula tactus. They are found in the skin around the sacs of the feathers, in the beak, and in the interosseus spaces of the fore- arm and leg. A special article (PACINIAN BODIES) has already been devoted to the organs of this kind which are met with in Mammalia, and it need only be added here, that late re- searches have shown that the Pacinian bo- dies of mammals, like those of birds, are solid masses of rudimentary connective tissue; the appearance of capsules and of a central cavity, arising merely from the arrangement of the elastic element and the extreme transpa- rency of the collagenous substance. * They are in fact nothing but thickened portions of the neurilemma, and the nerve which they enclose either passes through them, or more usually * This fact was ascertained and stated indepen- terminates, more or less abruptly, in the cen- tral solid axis. In the article on the PACINIAN BODIES re- ference is made to the peculiar organs de- cribed by Savi in the Torpedines. These Savian bodies, in fact, are little more than Pacinian bodies converted into sacs by the development of a cavity between their cen- tral and peripheral portions. Now Leydi" has discovered that these feavian bodies do not stand alone, but that they form a part of a great series of peculiar integumentary sen- sory organs, which are most characteristically, if not solely, developed in the class of Fishes — the so-called mucous canals and follicles. It has long been noticed, in fact, that in osseous fishes one series of the scales along the sides of the body differ in their structure from the rest, giving rise to what is called the lateral line; and that a canal runs beneath these scales from the tail to the head on each side ; that then becoming connected with its fellow by a transverse branch over the oc- ciput, each canal passes forward on the sides of the head, dividing into two principal branches, one of which following the course of the suborbital bones terminates at the end of the snout, while the other passes down on to the lower jaw. Similar organs, but having a more complicated arrangement, are known to exist in the cartilaginous fishes ; but it is com- monly supposed that these canals and follicles secrete the mucus with which the skins of fishes are lubricated. However, in a very beau- tiful series of researches, Leydig has shown that the mucus is furnished by the cellular ecderon, and that the so-called mucous canals and follicles are sensory organs. The limits of this article will not permit me to enter into any of the details of structure of these organs, but they may all be described generally as sacs or canals lined by a cellular investment like that of the skin upon which they open,' and filled with a more or less gelatinous sub- stance. If the organ be a sac, a single pro- tuberant knob, if a canal, a series of them pro- ject into the cavity. Each knob is covered by a coat consisting of tiers of much-elongated cylindrical cells. Its substance consists of niore or less gelatinous connective tissue, and it receives a nerve (a branch of the fifth or of the vagus), whose fibres divide and become lost in its tissue. In the osseous fishes this nerve usually perforates the peculiarly modified scale of the lateral line, which supports and encloses the canal at these points. In the cartilaginous nsnes, the canals have sometimes special fibro- cartilaginous coats; or if sacculi, a number of them may be contained in a common cartila- ginous investment, as in the Chima?ra. Leydi" insists with great justice on the identitv of the structure of these organs with that of the semicircular canals of the ear. The connection of these sacs and canals with the corpuscula tactus and Pacinian bodies dently and contemporaneously in 1853, by Leydur and myself. See Quarterly Journal of Mk? Science No. V., and Siebold and Kolliker's Zeit- schnft, B. v. Heft 1. TEGUMENT ARY ORGANS. 505 appears to me to be clear ; for the knob which projects into the cavity of the mucous canal is homologous with the central " nucleus " of the Savian body, and this with the solid axis of the Pacinian body,and with the corpusculum tactus, so that the " tactile " sac of the Chi- maera, e. g., may be said to be a tactile cor- puscle which is connected with the surface of the integument. No organ at all resembling these has cer- tainly been met with, above the class of Fishes, in either Reptilia or Birds, but in Mamma- lia there are structures which must, I think, be placed in the same category. About the lips and nose of almost all mammals in fact, there are certain long, strong hairs, the vi- brissae or "whiskers" (fig. 321.). These in their general structure resemble ordinary hairs, but the sac of each, instead of lying free in the enderon, is enclosed in a second thick sac, composed of firm, dense, connective tissue, which attains at times an almost cartilaginous hardness. A looser areolated tissue connects this with the outer surface of the proper hair sac, and supports an abundant .vascular net- work proceeding from vessels which enter at the deep end of the sac. Furthermore, a very considerable nerve pierces one side of the " sclerotic " coat near this end, and passes to the surface of the proper hair sac, upon which it spreads out and forms a nervous expansion, its fibrils dividing and subdividing, and so terminating. Fig. 321. mammal and the fish, I think one cannot but be struck with the similarity of plan between their vibriss»3 and the " tactile " canals. The sensory impression is conveyed to the gelati- nous contents of the canals in the fish by the vibration of the dense medium in which it lives; while in the mammal the impulse is communicated by the contact of some external object with a long elastic hair lever; but the final arrangement for the receipt and appre- ciation of the impressions is essentially the same in each case, nor indeed does it differ from that which is met with in the highest organs of sense. Muscles of the enderon. — In the Invertebrata the great majority of the muscles are, as is well known, inserted into the integument, but those which are attached to the chromato- phora of mollusks and to the spines of an- nelids and other worms, might be regarded as belonging more especially to the integu- mentary system. In Fishes and Reptiles the superficial layer of striped muscles of the body is always more or less connected with the integument ; but hitherto no unstriped fibres appear to have been detected in it. In Birds, however, the unstriped muscles attain a very great develop- ment, forming a thick layer whose bundles (c) run between and are attached to the sacs of the feathers (Jig. 322.). Fig. 322. Vibrissa from the snout of the Mouse, a, " sclerotic " sac ; 6, hair-sac ; c, nerve-trunk ; d, muscular fibres. Considering the different habits of life of the Pacinian body (6) and feather-sac (a) from the base of the mandible of a pigeon, c, muscles of the feather sacs. In the majority of Mammals there is a special teguraentary striped muscle, which attains an enormous development in the hedgehog, while a mere rudiment of it remains in man, as the platysma myoides. Here, however, the striped "peaucier" muscle is replaced by the unstriped bundles which, as Kolliker has shown, run from the upper layer of the enderon to the bases of the hair sacs, and effect the various movements of which the hairs are capable. 506 TEGUMENTARY ORGANS. Calcareous deposits in the cnderon. — Deposits of this kind are very frequent in the Inverte- brata. In the Pulmonate and some Gasteropod Mollusks, for instance, globular masses of car- bonate of lime are scattered through the en- deron, and would almost seem to take the place of fat. In nudibranchiate mollusks, such as the Dorida3, spicula of like nature are met with, and these sometimes unite into true internal shells, as in the genus Villiersia. The greater part of the skeleton of the Actinoid polypes, and the whole of that of the Echinoderms, is composed of calcareous networks of this kind, and globular masses of calcareous matter are scattered through theenderori of the Taeniadae, though the clear spherical bodies observed in these worms are by no means always of this nature. Whether these ^nderonic calcareous deposits ever take place in the Vertebrata ap- pears to me to be, as I have said above, an open question, only to be decided by a very careful examination of the mode of growth of their so-called "dermal" bones. BIBLIOGRAPHY. — General Works. — Heusinger, Histologie. Quekett, Lectures on Histology. VERTEBRATA. Gurlt, Untersuchungen ttber die hornigen Gebilde d. Menschen u. d. Haus-sauge- thiere (Mliller s Archiv., 1836). Idem, Vergleichende Untersuchungen tiber die Haut der Menschen und d. Haus Saugethiere (Muller's Archiv., 1835). Meyer, Haut d. Cetaceen. Meyer, Baa d. Haut des Gurtelthieres (Muller's Archiv., 1848.) Eble, Lehre von d. Haaren, (Consult also for the Hairs, &c. the works cited in Henle's Allgemeine An- atomie, and Kolliker's Mikroscopische Anatomic.) Feathers : — Dutrochet, Observations sur la Structure et la Regeneration des Plumes (Journal de Physique, Ixxxviii.). F. Cuvier, Observations sur la Structure et Developpeinent des Plumes (Mem. du Museum, xiii.). Michel, (in Reil's Archiv., xiii.). South, Art. Zoology ( Encyclopaedia Metropolitana.) Scales and integumentary organs of fishes. — Leeuwenhoeck, Arcana Naturae. Reaumur (Mem. de 1'Acad. Roy. des Sciences, 1716). Mandl, Sur les Ecailles des Poissons (Annales des Sciences Naturelles, 1839.). Agassiz, Observations sur la Structure et le Mode d'Accroissement des Ecailles des Poissons (Annales des Sciences Naturelles, 1840 ; and Poissons fos- siles, Vol. I.). Williamson, On the Microscopic Structure of the Scales and Dermal Teeth of some Ganoid and Placoid Fish (Phil. Trans. 1849). Williamson, On the Structure and Development of the Scales and Bones of Fishes (Phil. Trans. 1851). Leydig, Histologische Bemerkungen ttber den Polyp- terus bichir (Siebold und Kolliker's Zeitschrift, 1853). Leydig, Beitrage zur Mikroskopischen An- atomic und Entwickelungs Gesehichte der Rochen u. Haie, 1852. Leydig, Haut der Sttss-wasser Fische (Siebold u. Kolliker's Zeitschrift, 1851). Leydig, Schleim-kanale d. Knochenfische (Muller's Archiv., 1850). Peters, Report on the Memoirs of Mandl and Agassiz (Muller's Archiv. p. ccix. 1841). Rathke, Ueber die Beschaffenheit des Lederhaut bei Am- phibien und Froschen (Muller's Archiv., 1847). Czermak, Ueber die Haut Nerven des Frosches (Muller's Archiv., 1849.) ANNULOSA. — Lavalle, Annales des Sciences Naturelles. Carpenter, Report on the Microscopic Structure of Shells (Rep. Brit. Assoc. 184S). Mayer, Ueber den Bau d. Hornschale der Kafer (Muller's Archiv., 1842). Newport, On the Natural History and Development of the Oil- beetle Meloe (Linnaian Transactions, 1845-7). Leydig, Ueber Argulus foliaceus (Siebold und Kolliker, Zeitsch, B. II.). Leydig, Zur Anatomic von Piscicola geo- metrica (Zeitsch. I.). Let/dig, Ueber Artemia salina und Branchipus stagnalis (Zeitsch. III.) Hollard, Recherches sur les Oaracteres anatomiques des De- pendances de la Peau chez les Animaux Articules (Revue et Mag. de Zoologie, 1851). Meissner, Beitrage zur Anatomic und Physiologic von Mermis albicans (Siebold und Kolliker's Zeitschrift, 1853). Quatrefages, numerous Memoirs in the Annales des Sciences. MOLLUSCA. — Poll, Testacea utriusque Sicilian, 1791. Gray, Some Observations on the Economy of Molluscous Animals (Phil. Trans. 1833). Car- penter, Report, &c. (Reports Brit. Assoc, 1845). Leydig, Ueber Paludina vivipara (Siebold und Kol- liker's Zeitschrift, 1850). Leydig, Anatomische Bemerkungen ueber Carinaria, Firola, und Amphi- ora (Zeitschrift, 1851). (T. H. Huxley.} RUMINANTIA (Lat. ruminare, to chew the cud), Eng. Ruminants ; Fr. Ruminans ; Ger. Wiederk'duende T/tiere, — a well denned order of mammalian quadrupeds, presenting the following essential characters : Upper jaw in nearly all cases destitute of incisor teeth, their place being supplied by a callous pad, while the lower jaw has six incisives ; canines inconstant ; molars usually six on each side of both jaws, with flattened crowns surmounted by two double and irregularly crescentic folds of enamel. Stomach com- pound and divided into four cavities, so as to provide for the ruminating act. Ccecum large. Placenta generally in the form of cotyledons. Feet ungulate and bisulcate. This order forms two natural divisions, comprising the Hornless ruminants (akera- tophora, Col. H. Smith) which are few in number, and the Horned ruminants (kera- tophora) which are very numerous. The English naturalist Ray, who was the first to propose a classification based on philosophical principle, enumerated only fifteen species. Pallas subsequently divided the entire family into six genera, and the Baron Cuvier into eight or nine; but the number of subdivisions held to constitute genera by later authorities has been very greatly extended. To serve our present purpose we shall retain only the Linnean and two other genera, which may be conveniently arranged under the five following heads or sub-orders : — Camelus - \Auchenia - TMoschus - < Cervus (Camelopardalis f Antilope - | Catoblepas ( Capra lOvis Bovis The Camelidse differ in many important particulars from the horned ruminants, and exhibit an approximation to the Pachy- dermata. The dental formula is peculiar; thus in the genus Camelus there are, — I. CAMELIDSE II. CERVID^E III. ANTILOPID^E - IV. (EGOSCERIDJE - V. BOVIDJE - Linn. Illiger. Linn. Linn. Linn. Linn. Smith. Linn. Linn. Linn. 3 3 1 1 1 1 3 3 and in this respect the Auchenias, or Llamas, disagree only in the number of molars, which is usually fourteen. The distinguishing fea- tures of this family depend principally upon RUMINANTIA. 507 the beautiful provision of water-cells in the stomach, the absence of horns and the sub- walls of the paunch or first cavity of the bisulcate feet, which are "callous beneath, and Fig. 323. Skeleton of the Camel. (From Pander and D'Alton.) have the toes distinct at the tip from the or cotyledonoid form of placenta. Professor sole."* The uterine and foetal membranes Owen has demonstrated another remarkable are unprovided with the ordinary ruminant character arising out of the non-development Fig. 324. Skeleton of the Deer. (From Pander and D'Alton.) * Ogilby. 508 RUMINANTIA. of foramina for the passage of the vertebral arteries through the transverse processes of the lower six cervical vertebrae. This ana- tomical arrangement occurs in no other existing tribe of mammifers, but in an aber- rant form of fossil pachyderm (Macrau- chenia), Dr. Owen has detected the same anomaly, and has thus established an ad- ditional connecting link between the Pachy- dermata arid Ruminantia. In the classification of the Cervidae given above we have included two genera not usually considered as forming a part of this family. One of the principal characters of the Cervidae proper consists in the presence of deciduous horns or antlers : the genus Moschus, however, like the Camelidae, is hornless; and the genus Camelopardalis is provided with persistent horns which are at all times clothed with a hairy integument. The dental formula of the Cervidae and all other horned ruminants is usually as fol- lows, — 0 0 3~3 0 0 1 1 -M 3 3 3 3 32. The Musk-deer tribe have in addition two long and conspicuous canines in the upper jaw, projecting in the males below the mouth, (fig. 330.). The male Kijang or Muntjak (Cervus muntjac, Zimmerman) has likewise two prominent canines in the upper jaw (a, fig. 331.). In the Giraffe there is a complicated glandular and pouch-like struc- ture in the neighbourhood of the ileo-colic valve.* The Antelopidae include the greater num- ber of the Cavicornua or hollow-horned division of ruminants in which the bony axis of the horn is solid, persistent, and destitute of cavities or pores. They have, for the most part, a slender figure adapted for rapid pro- gression, and, like the Stags, are further dis- tinguished by the possession of infraor- bital glandular sinuses. Under the term (Egosceridae (CEgosccros, Pallas) we have brought together the closely allied genera Capra and Ovis. The Goats are characterised chiefly by their long horns, which are directed upward and backward, are more or less angular in front, rounded behind, and generally marked by transverse bars or ridges. The chin is clothed with a long beard. The Sheep which have no beard differ mainly in having the horns directed at first backward, and subsequently bent spirally forward. Between the toes at the anterior aspect of the feet is situated a special glan- dular sebaceous sac ; this structure is also found in other ruminants, — the Rein-deer, for instance. Neither the Sheep nor Goats exhibit the lachrymal sinuses so character- istic of the majority of the Antelopes and Stags. Fig. 325. Skeleton of the Cow. (From Pander and D'Alton. The Bovidce present few anatomical pecu- liarities not shared by the preceding genera. As regards external configuration, however, they are at once recognised by their bulky massive size, the broad muzzle, and powerful limbs (fig. 325.). The horns are directed laterally, with an inclination upward more or less curved. In their habits and in the struc- ture of the skin, some of the species, the Buffaloes, for example, approach the pachy- dermatous type. Osteology. — The general form of the skull in ruminants, when viewed laterally, is that of an isosceles triangle, the base of which is represented by the occipital crest and rami of the jaw, and the apex by the incisive pro- minence ; but exceptions occur, as for instance, in the common sheep, where the frontal bones are so much arched as to produce a somewhat oval figure, and in the camel, where, owing to the abrupt termination of the nasal and sudden depression of the intermaxillary bones, an obliquely quadrilateral form is the result (fig. 331). The forehead is usually- straight and elevated, the orbits are placed wide apart, and the muzzle, except in Bovidaj, * See " Viands of Intestine" in this Article. RUMINANTIA. 509 is attenuated and compressed. Throughout the whole order there prevails considerable disparity as respects the cranium and face; the bones of the latter occupy fully two- thirds of the entire length of the skull, and the area of the face on section is nearly double that of the cranium. Bones of the cranium. — Eight bones enter into the composition of the adult cranium ; viz , an occipital, a parietal, two frontal, a sphenoidal, an ethmoidal, and two temporal ; and, in addition to these, some species are provided with two ossa triquetra or inter- parietals. Fig. 326 Skull of the Ox viewed from behind. (From a spe- cimen in Lond. Coll. Surg. Museum.) The occipital bone (1 !,./%• 326.), as in most of the mammalia, is originally divided into four, one superior, one inferior, and two lateral pieces (11', Jig. 326.). These become early consolidated, and in the calf at the time of birth they are firmly united together and to the parietal and interparietal bones lying immediately in front. The occipital crest is prominent in the Llamas, and still more fully developed in the true Camels. In Bovidae the crest corresponding to the occipital is formed by the junction of the parietal and frontal bones, the superior occipital remaining flat. In ruminants generally, the paramastoid pro- cesses (/ Jig. 326.) are much elongated, falci- form, and curved inwards, and between these and the occipital condyles (i) a very deep fossa intervenes. In Camelidae, at the angle formed by the union of the petrous portion of the temporal with the lateral and superior occipitals there is a large opening on either side. In this family the anterior condyloid foramina are of moderate capacity, but in Cervidae they are of great size and some- times four in number, in which case two remain small. In CEgosceridse and Bovidae they are also large and occasionally double. The parietal (9*) is single, and with a few trifling variations, is articulated to the cranial bones in the usual manner. The lambdoidal or parieto-occipital suture lies considerably in front of the crest, except in Bovidae, where it lies below, and is separated from the frontal suture by the intercalated and narrow wedge-shaped parietal bone. The (Egosceridae have the parietal in the form of a flattened band, encircling the cranium and extending between the orbitar wings of the sphenoid on either side (b,Jig. 335.). It is broader in the goats than in the sheep. In Bovidae the parietal does not extend so far forward (b. fig. 327.). In the Giraffe the lateral processes of the parietal are narrowed Fig. 327. Skull of the Ox, viewed laterally. (From Spix.) to a mere point, but the body of the bone which reaches from between the horns as far back as the occipital crest has a longitudinal diameter of fully six inches. The coronal or fronto-parietal suture in this species and a few other genera is situated in a line with the osseous protuberances which support the horns. It is most frequently placed behind ; in the Gazelles, however, it appears in front. The frontal bones (8) are of large size and great breadth ; this latter feature being more especially manifest in the Camels, the Sheep, and certain bovine species. In the Came- lidae they extend backward between the anterior divisions of the parietal bone, and in front they are articulated to the lachrymals by a transverse suture, which is less extended in the Llamas than in the true Camels. In the Llamas and in the genus Moschus a small part of the frontal is connected to the superior maxillary. There are several supra- orbital or frontal foramina (c) with rounded orifices, which in the Camels are placed near the middle line and at the centre of the fore- head. In the Llamas these openings are placed rather farther back and united by a longitudinal groove. The frontals are ele- * The numerals here refer to all the subjoined figures of crania with the exception of figs. 327. and 335. 510 RUiMINANTIA. vated posteriorly in Bovidae (c, fig. 327.) and prolonged toward the occipital crest, in the formation of which they apparently con- tribute,— a circumstance giving rise to the peculiar physiognomy characteristic of the group. The osseous protuberances support- ing the horns, of which we shall speak more particularly when describing the latter in detail, take their origin in most cases from the frontal bones. In the Giraffe the slight eminences analogous to the osseous cores are partly formed by the parietal bone, the coronal suture passing directly through the centre from side to side (Jig. 328.) ; the an- Fig. 328. Front view of the skull of a Giraffe. (From a spe- cimen in Lond. Coll. Surg. Museum.) terior or central eminence, situated imme- diately behind the nasals, and in part formed by them, differs in no respect, save as regards its position, from the other two, the elevation in all instances being produced by the expan- sion of the cranial sinuses beneath. There is a single large supra-orbital canal, having its superior outlet midway between the upper border of the orbit and the central frontal eminence (Jig. 328.). In Cervidae generally, the canal opens at the upper surface by a longitudinal furrow (fig. 329.), but this is more particularly marked in Bovidae ( fig. 333.). In regard to the cranial sutures in Cervidae, M. F. Cuvier observes that " all those por- tions, such as the second half of the frontal, the greater part of the coronal, and the occi- pital or lambdoidal, which surrouud the base of the core, exhibit an excessive multiplication of interlineations, because the weight of the horns and the shocks to which the parts are exposed require that the bones should be firmly connected" (fig. 329).* The sphenoid (l£) articulates, except in Bovidae. with all the cranial bones; but its orbitar wing, which is largely developed, is concealed in great measure within the cere- bral cavity, and covered by the lateral expan- sions of the frontal bones. In the Camelidae the pterygoid processes of the sphenoid are directed vertically downwards and terminate in two laminae, the external one being longer and larger than the internal : the latter pro- cess only makes its appearance very low down, and is so closely applied to the ex- ternal lamina, as to leave scarcely any trace of a pterygoid fossa ; neither is there any space between it and the wing of the palatine bone. In this family the spheno-orbitar fissures and the spheno-palatine foramina are of great size. The optic canals are only separated from the former by a thin osseous partition, and the openings for the passage of the third branch of the fifth pair of nerves are rounded and placed far back The Cervidas have the posterior division of the sphenoid developed into an extremely attenuated and short tem- poral wing, which, nevertheless, is articulated to the parietal, the lateral processes reaching very far forward. The orbitar wing of the sphenoid in the same family separates into two divisions, one extending upwards and back- wards, and also uniting with the parietal, the other being prolonged horizontally forward, between the frontal and palatine bones, and terminating anteriorly at the border of an opening which corresponds to the spheno- palatine foramen. In the Giraffe the temporal wing of the sphenoid is short and connected by a well-marked suture to the T-shaped process of the narrow lateral expansion of the parietal ; it approaches very closely, but is not united to the orbitar plate of the frontal as has been conjectured. In the work last alluded to in the foot-note it is stated that the frontal and sphenoid bones are united at an early period, rendering it difficult to make out their limits. In the cranium of a Giraffe about two years old, and at present in our possession, the sutures involved in the union of the above-mentioned osseous segments, fortunately yet remain distinct, and in this individual the orbitar wings of the sphenoid do not divide into two laminae, as seen in the Stags, but at the floor of each orbit they form a broad, short, and triangular fan-shaped plate, the centre of which is pierced by the hole for the passage of the optic nerve. The spheno-orbitar apertures are round and of enormous size in the Giraffe : in the Stags the spheno-palatine foramina are also large ; and this is more especially the case in Camelo- pardalis, where they lie concealed behind the molar prominences. In the genus Moschus the anterior sphenoid is largely developed, and its wings form the greater* part of the posterior wall of the orbits. The body of * Cuvier, Lecons d'Anat. Comp., 2de edit. torn. ii. p. 366. RUMINANTIA. Tig. 329. 511 Front view of the skull of the Deer. (From Lond. Coll. Surg. Museum.) this portion of the bone is compressed, and, in consequence of a central space left unossi- fied (Jig. 330.), we are enabled to look into Fig. 330. Side view of the skull of Moschus. (From a specimen in Lond. Coll. Surg. Museum.) the orbit of the opposite side ; a peculiarity not confined to the animals under con- sideration, being more marked in certain of the Rodentia and in birds. In Bovidae the temporal wing of the sphenoid, which is of comparatively large size and much curved backward, does not reach the parietal bone as in the other ruminants ; and it is further distinguished by a sharp pointed ridge de- veloped from its anterior margin, which in the preceding genera is only feebly indicated, though tolerably prominent in the Giraffe. The anterior wing extends horizontally for- ward and is convex on its orbitar surface (d,fig. 327.). Part of the body of the pos- terior sphenoid forms, in conjunction with the anterior third of the basi-occipital, two projecting elevations, which are separated from each other by a deep groove : these also appear in the Goats, where they are less marked. In both families the spheno-palatine and the spheno-orbitar foramina are capacious ; but in GEgosceridae the latter openings are somewhat compressed. The os ethmoides has the same relations as usual, its cells being greatly developed in the Giraffe. The temporal bone (10), as in other mam- malia, consists of three segments. In Came- lidae the zygomatic arches form, in conjunction with the sunken temples and strongly pointed occipito-parietal crests, a striking feature, which imparts to the cranium of this family a carnivorous type of structure. This mor- phological peculiarity is chiefly noticeable in the Camels properly so called ; and in them the glenoid cavity is very deep, being sup- ported in front and behind by prominent apophyses, the posterior of which is united at 512 RUMINANTIA. its base to the tympanic bulla (fig. 334.). The latter is much compressed, and also firmly connected above to the paramastoid apophyses of the occipital, leaving a con- spicuous cavity between. In the Llamas, at the root of the zygomatic apophysis, there is a large round foramen immediately above the external meatus. In Cervidae and Antelo- pida3 the post-glenoid apophysis is feebly developed, and the base of the zygoma is flattened and prolonged backwards toward the occipital crest ; the squamous portion is rather extensive and the tympanic bulla of large size. Similar arrangements obtain in the Giraffe, but the zygomatic apophyses are more curved than in the Stags. The base of the zygomatic process in many of the Ante- lopidae is pierced by an oval opening, which is situated midway between the external auditory meatus and the glenoid facet ; and from it there sometimes proceeds a fissure, which takes an upward direction, to join the parieto-temporal or squamous suture.* This foramen occurs in the Muntjack deer (Jig. 331.), and, as we have before stated, in the Fig. 331. Cranium of the Muntjack. (From Lond. Coll. Surg. Museum.) Llamas also. In CEgosceridae the squamous portion of the temporal is comparatively small (e, Jig. 335.), and the tympanic bulla, which is moderately large and somewhat flattened, terminates by a sharp styloid pro- cess anteriorly. The post-glenoid apophysis is represented by a very narrow ridge of bone, leaving only a slit-like cavity between it and the meatus. In Bovidae the temporals (, fig. 334.), cells, yet their significance is not the less analogous to the similar but more marked apparent or important when considered in a apophysis in Carnivora. physiological or ideological point of view. Cranial peculiarities. — Under this head we It has been considered necessary to pre- proceed to notice certain arrangements re- serve the cranium of the Giraffe at present in quiring further attention, and in the first our possession entire ; consequently, we are place 'the remarkable sinuses which exist in unable to offer any account of these sinuses the skull of the Giraffe. Though these be from personal examination, which is the less nothing more than an extension of the to be regretted, as Prof. Owen has placed Fig. 338, Sectional view of the cranium of the Giraffe. (From Owen.) on record the following description of this structure*: "The part of the skull to which the elastic ligament is attached is raised considerably above the roof of the cranial cavity by the extension backwards of large sinuses, or air-cells, as far as the occiput. The sinuses commence above the middle of the nasal cavity, and increase in depth and width to beneath the base of the horns, where their vertical extent equals that of the cere- bral cavity itself. The exterior table of the skull, thus widely separated from the vitreous table, is supported by stout bony partitions, extended chiefly in the transverse direction, and with an oblique and wavy course. Two of the most remarkable of these bony walls are placed at the front and back part of the base of the horns, intercepting a large sinus immediately over the middle of the cranial cavity, and from a third and larger one be- hind. The sphenoidal sinuses are of a large size." Slight differences in the development of the cranium are found in Giraffes inhabiting respectively the more northern or southern regions of Africa, these peculiarities having especial relation to the position and approxi- mation of the horns. In the Abyssinian specimen (about two years old) dissected by us, several particulars were noted, a few of which are here selected -j- : — * Memoir on the Anatomy of the Nubian Giraffe, Zool. Trans, vol. ii. p. 235. t Dr. Cobbold, On the Anatomy of the Giraffe, Annals of Nat. Hist, for June, 1854. Inches 19 8f 'it ¥ l\ Jt Length of cranium - Breadth between orbits - Incisive angle to central eminence Length of horns - Distance between horns at the base - Depth of orbit - Diameter of orbital ring - Breadth of occipital condyles - Vertical depth of each condyle - Length of lower jaw - In this list will be remarked the extreme elongation of the bones of the face, as shown by the distance of the incisive angle from the central prominence — the great depth of the orbits — the narrow space between the bases of the horns — the length of the jaw — and more particularly the extended vertical dia- meter of the condyloid facets of the occipital bone. The elongation of these articular sur- faces in the direction indicated, permits of the head being drawn into a line with the neck, and Prof. Owen states, from observing this action in the living animal, that he has seen it stretched backward beyond this line. Horns. — In the Giraffe we have a unique example of solid persistent horns, completely invested with a hairy integument. They are placed on two bony elevations, having a position analogous, in some respects, to that of the osseous cores of the Stags ; but, being separated from them by a synchondrosis, they are to be regarded as independent develop- ments or " epiphyses " and not " apophy- sial " outgrowths (fig. 328.). As has been al- ready observed, the protuberances are formed in part by the parietal and frontal bones, the RUMIKANTIA. 517 coronal suture passing transversely across the centre of each osseous expansion, from side to side. The bones are easily detached by maceration (at least in the younger ani- mal), and when withdrawn, there is brought into view an intervening sheath-like perios- teum, which can also be separated from the concavity at the base of the horn. This cup- shaped hollow, owing to the colamnar dis- position of the osseous laminae, and the very numerous perforations for the passage of nutrient vessels, presents the appearance of a sieve, depressed into a conical form. Both in the Cape and Nubian varieties a sexual difference obtains in reference to the extent to which the horns are developed. In the male adults they are larger and more closely approximated at the base than in the females, and, according to Prof. Owen's observations on the horns of the Cape Giraffe, " their expanded bases meet in the middle line of the skull, so that they would entirely conceal the coronal suture even if it were not early obliterated in this sex." * The basal portions of the horns in the females are widely sepa- rated. In our specimen (a Nubian male) the internal and lower margins of the horns remain, severaHy, half an inch apart, and the interfrontaf suture is still distinct throughout its entire length. In regard to the asserted existence of a third horn surmounting the anterior central protuberance, an examination of the cranium, above alluded to, only serves to confirm the extended observations and conclusions of Prof. Owen on this subject. We have shown that this elevation is due to an enlargement of the subjacent frontal si- nuses, and in this respect it resembles the posterior horn-shaped apophyses. It must be remarked, however, that although, in our example, there is no superimposed osseous deposit, there is, nevertheless, a cartilaginoid thickening of the periosteum in that situa- tion ; this, we can readily believe, might con- stitute a nucleus favourable to the formation of an epiphysis similar in all respects to the true horns lately described. We have not had an opportunity of inspecting the crania in the museum of the Royal College of Sur- geons, London, but, through the kindness of Dr. Bail, have examined the skeleton of a male Giraffe which died (during sexual ex- citement) at the Dublin Zoological Society's Gardens, and which is now preserved in Dr. Harrison's Anatomical Museum. In this in- dividual the central cranial eminence is not smooth as in our specimen ; on the contrary, it is particularly rough, owing to the deposi- tion of osseous nodules, which bear a marked resemblance to the irregular bony laminae prolonged from the attenuated margins of the bases of the true horns. If these rough prominences could be shown to be separable by maceration, we might with good reason infer the rudimentary existence of a third horn ; if, on the other hand, they are merely exostoses or outgrowths (and to this opinion * Memoir, loc. cit. we incline), we think their deceptive aspect offers, in some measure, an explanation of the incorrect description of this structure recorded by Cuvier, and the inaccurate figure given by RUppell.* The deciduous branching horns of the deer present two well-marked morphological types, — one group possessing rounded antlers, and the other having them more or less flattened and palmated. Of the former, characteristic examples are seen in the horns of the Roe- buck (C. capreolus} and Red Deer (C. ela- phus), — and of the latter, in the Elk (C. alecs') and Fallow Deer (C. damas). The re- markable periodical development of these cra- nial outgrowths is most interesting in a physio- logical point of view, and both types of struc- ture exhibit the same general law of increase. The male calf of the Red Deer at the sixth month differs from the female of the same age, in having two small elevations or " bos- sets," which represent the first indication of horns. These processes acquire, in the second year, the form of simple unbranched stems or "dags " (a, jig. 339.), at which date the deer Fig. 339. Development of the horns in the Red Deer. (From Cuvier.) is designated a "brocket" by the English, and by the French a " daguet." The dagger- like horn being shed, its place is occupied in the third year by another, carrying usually one, but sometimes two, and even three branches or " tynes " (b, c) ; in this condition he is called a " spa) ard." The horn of the fourth year assumes a more complex aspect (d, e), and the summit or " crown " of the stem begins to spread and divide ; at this stage he is styled a " staggard." At the fifth year there are five OF six branches, and at this period he is termed a " stag." At and after the sixth and seventh years the number of "tynes" is very variable', and the growth of the horn being now perfected, the individual is technically denominated a "hart" (/). The palmated horns of the Fallow Deer exhibit similar gradations of development. At the second year the " buck-fawn " or * Atlas zu der Reise in Nordlichen Afrika, von Edouard Ruppell, PI. 9. Since the above was writ- ten Prof. Quekett has politely afforded us an op- portunity of inspecting the crania in the Hunterian Collection. The osseous nodules noticed in the Dublin specimen not only exist in one of these crania, but they could be partly raised from the subjacent bone by the easy insertion of the finger- nail under the margin. L L 3 518 RUMINANTIA. "pricket" puts forth a simple "dag" or cylindrical shaft (a, % 340.), which is slightly bent forward. In the third year the branch- ing commences, and he is said to be a "sorel" (6). The antlers in the fourth year grow more numerous, and the stem is bifid at the summit (c) ; at this period the Fallow Deer is Fig. 340. Development of the horns in the Fallow Deer. (From Cuvier.) entitled a " sore" by sportsmen. After this date the upper part of the brain or shaft becomes more palmated, and irregular serra- tions or " snags " are produced at the margin (d) ; the animal is now a " buck of the first head," and, as age advances, the snags en- large, and take on, more or less, the appear- ance of true antlers. In the Rein Deer the horns undergo a similar metamorphosis ; they are of great size in both sexes, but are some- what less branched and slender in the fe- male ; the brow-antlers are much prolonged forward over the forehead. The nature of the anatomical change which takes place in the adult individual during the periodical renewal of the antlers, is characterised by, and contemporaneous with, the following phenomena ; — a strong determination of blood to the head takes place at the spring of the year, and the vessels surrounding the frontal apophyses enlarge. This increased vascular action re- sults in the secretion of a fibro-cartilagi- nous matrix, manifesting itself externally by a budding, commencing at the summit of the " core," at the spot where the horns of the previous season had separated. In the early condition the horn is soft and yielding, and it is protected only by a highly vascular periosteum and delicate integument, the cu- ticular portion of the latter being represented by numerous fine hairs, closely arranged. From this circumstance the skin is here termed the " velvet." As development goes on, a progressive consolidation is effected, — the ossification proceeds from the centre to the circumference and a medullary cavity is ultimately produced. While this is taking place a corresponding change is observed at the surface. The periosteal veins acquire an enormous size and by their presence occasion the formation of grooves on the subjacent bone. At the same time osseous tubercles, of ivory hardness, appear at the base of the stem ; these coalesce by degrees and enclose within their folds the great superficial vas- cular trunks, which are thus rendered imper- vious. The supply of nutriment being cut off, the first stage of exuviation is accom- plished by the consequent shrivelling up and decay of the periosteal and integumentary envelopes. The full growth of the horns is now consummated, and the animals, being aware of their strength, endeavour to com- plete the desquammation by rubbing them against any hard substances which may lie in their path ; this action is technically termed " burnishing." After the rutting season the horns are shed, to be again renewed in the ensuing spring. The disposition of the horns is invariably symmetrical in a state of health, but the antlers are sometimes disproportionate on either side and their growth incomplete from deteriorating circumstances. A remarkable sympathy exists between the generative or- gans and the horns, and any imperfection in the one induces a corresponding change in the other. In consequence of this reciprocal influence, the development of the horn may be arrested and the periodical shedding pre- vented by castration. An illustration of this is to be seen in the cranium of a Fallow Deer preserved in the College of Surgeons' Mu- seum, London. The horns of ruminants are seldom more than two in number, but ex- ceptions occur in the case of the extinct Bramatherium and gigantic Sivatherium (fig. 341.) found in the tertiary deposits of Northern Fig. 341. Front view of the cranium of the Sivatherium. (From a model in the Lond. Coll. Surg. Museum.) India. Living instances of more than a single pair are seen in the Four-horned Goat and Many-horned Sheep ; also in the Jung- liburka Antelope (A. subquadncornutus) where the anterior pair are rudimentary, and in the Chousingha (A. quadricornis}, several species of which have been described by authors(^g.342.). The structure of the horn in Cavicornua is exceedingly simple. The frontal " apophy- ses " or " cores," instead of branching, form cylindrical shafts, more or less solid, the surface being protected by the ordinary peri- osteum, and by an extension of true skin, the cuticular portion of which is developed into a dense horny sheath (fig. 333.). If a trans- verse section be carried through the base of the " core," a number of cavities will be ex- posed, which are continuations of the frontal RUMINANTIA. sinuses. These spaces do not exist in certain of the antelopes, as for example in the Gazelle (A. dorcas) and the Sasin (A. cervicapra). The horns exhibit a great variety of curva- Fig. 342. D. Front view of the cranium of the Choustngha. (From a specimen in Lond. Coll. Surg. Museum.) ture and outline, and in those of the Cabrit or Prong. horn Antelope (A. furcifer), we have an approach toward the cervine type. The prong is situated about half way up, and may be considered as analogous to the brow- antler ; immediately below it the root is rough, scabrous, and nodulated, being co- vered also by a hairy integument {fig. 343.). Fig. 343. Horns of the Cabrit. (From a specimen in Lond. ColL Surg. Museum.) In the Buffaloes the horns acquire a pro- digious size, and the cuticular sheath forms, in some instances, a thick envelope over the entire forhead. Vertebral column and bones of the trunk. — Considerable disparity prevails in the length of different portions of the spine, depending upon the comparative elongation of the individual bones, and not upon their number. The following table, selected from Cuvier, illustrates the trifling deviations in a nume- rical point of view, — the seven cervicals being added and indicated in the totals : — Camel - 12 7 4 17 Vicugna 12 7 5 12 Moschus 13 6 3 14 Red Deer 13 6 4 16 Giraffe 14 5 4 18 Gazelle 13 6 4 14 Chousing Goat ha 13 13 5 6 4 4 14 12 Sheep 13 6 4 16 Ox 13 6 5 18 519 47 43 43 46 48 44 43 42 46 49 In Camelidse the bodies of the vertebras of the neck are much lengthened {fig. 323.), but it is in the Giraffe (fig. 345.) that we see the most remarkable conformity to the cer- vical type in this respect. The spinous pro- cesses of this division of the column are lessened in all mammiferous animals in pro- portion to the length of the cervix, and therefore we find them in the above men- tioned ruminants almost entirely effaced (ex- cept in the seventh vertebrae) to admit of free motion backward. This action is further facilitated in the Camels and in the Giraffe by the ball and socket-like conformation of the articular ends of each vertebral body, as pointed out by Profs. De Blainville and Owen. The anterior extremity of the " cen- trum " is convex (fig. 344.), and the poste- Fig. 344. Section of the cervical vertebra of the Camel. ColL Surg. Museum.) (From rior concave, but there is no intervertebrai synovial apparatus as seen in reptiles. The transverse processes in the short-necked typical ruminants are compressed, and form double " apophyses " on either side. The anterior or inferior pair are directed forward, and the posterior or superior project laterally, their common expanded base being pierced for the passage of the vertebral artery. In the latter particular, a similar arrangement obtains in the Giraffe, but the openings are placed nearer the spinal canal, because the transverse processes are feebly developed, as in all other long-necked ruminants. The Camels and Llamas do not exhibit the per- foration in question. In them, the vertebral arteries enter the posterior opening of the great neural canal, external to the dura-matral sheath, and in this position they are partly lodged in a groove at the base of the superior lamina. At the anterior part of the bone this channel becomes arched over for a short space, and converted into a distinct passage L L 4 520 RUMINANTIA. j. 344.}. The atlas in the Camels is not thus modified. In all other ruminants, in- cluding the Giraffe, an opening exists in this bone, which is placed at the fore part of the superior ring. The odontoid process of the axis or dentata is well marked and prominent in the short-necked ruminantia, but the Giraffe and Camels have it very small and incorporated with the articular end of the body ; in them, also, very slight traces of transverse " apophyses " are detectable. The dorsal vertebrae are distinguished for the great length and development of their spinous processes. The latter have an ex- traordinary elevation in the Giraffe, for the attachment of the powerful legamentum nu- chce, which is broadest at this point (Jig. 345.). The spinous " apophyses" are large in Fig. 345. Skeleton of the Giraffe. (From Pander and D' Alton.) the Bovidze, and still more bulky in Camelidae. The transverse processes of the lumbar ver- tebrae in the first-named family are extremely prominent, and have a straight lateral di- rection. In the swift-bounding Stags and Antelopes they are shorter, and a little curved forward. In Camelidae they are largely de- veloped, slightly bent downward, and abrupt at their extremities, the last pair being com- paratively short and narrow. The sacrum consists of three, four, or five pieces consoli- dated together, to the anterior of which the ossa ilea are articulated. The spinous pro- cesses form a single continuous crest. The caudal vertebrae vary in number, and, in the foregoing table, eighteen are assigned to this region in the Giraffe. Prof. Owen has counted as many as twenty in the Nubian variety. The Llamas, Stags, Goats, and certain of the Antelopes have the tail short, with a proportionate diminution of bony segments ; this appendage is of considerable length in the true Camels, the Gnus, the Oxen, and some of the Sheep. The ribs vary chiefly in respect of their size. The Giraffe has seven directly united to the sternum, and an equal number un- attached. Eight are true and five false in the Stag, and the same division occurs in the Ox. They are strong in the true Camels and in the Giraffe, being particularly broad to- ward the sternal ends. The same peculiarity holds good with most of the bovine species. In the Camel seven pairs are connected to the sternum, the anterior ones being straight and short; five remain unsupported. The ribs are very narrow in the Bison, and particularly slender in the Antelopes and Deer. The sternum is flattened in ruminants, its first bone being rounded in front, and somewhat attenu- HUMINANTIA. 521 ated. This is especially the case in the Giraffe, where the breadth increases towards the posterior border, at which point it is extremely thick. It is more or less curved in the Camel and Giraffe, particularly in the latter. We have observed in the skeleton of an Arabian Camel, preserved in the Edinburgh College of Surgeons' Museum, that the se- cond borip of the sternum is of very great bulk, while the first is small and flat ante- riorly. The pelvic bones are broad and strong in the Camels and bovine tribes, and compara- tively slight in the Antelopes and Deer. In the Giraffe and in the Camelidae the crest of the ileum is rounded, the neck long, and the upper surface of the bone concave. The ileum is extremely prominent and large in the Ox and Buffalo, and in respect of the neck, acquires an almost vertical position ; the prominence of the ischium is placed on a higher level than the cotyloid cavity. In ruminants generally, the posterior angle of the ischium presents the appearance of a tripod. The ischiatic notch is deep. In (Egosceridae, Cervidae, and Antelopidae, there is a depression immediately in front of the cotyloid cavity for the insertion of the ten- don of the straight muscle of the thigh. In Moschus, according to M. F. Cuvier, the sacro-ischiatic ligament and connecting apo- neuroses ossify, in consequence of which there is formed in this region a shield-like osseous plate extending from the crest of the ileum to the ischial tuberosity.* Bones of the anterior extremity. — There are no traces of a clavicle in this order. The scapula is long, and has the form of an isosceles triangle, the base of which is repre- sented by the spinal border, and the apical angle by the glenoid facet. In Camelidae the spine of the bone is prolonged downwards over the neck, forming, in this respect, an approach to the pachydermatous type. The acromion apophysis is likewise developed in Bovidae; but it can scarcely be said to exist in other ruminants. In every division of the family we find the neck of the scapula much elongated, and the extreme manifestation of this peculiarity in the Giraffe, together with a nearly vertical direction of the bone, pro- duces the remarkable elevation of the shoulder, characteristic of that animal. The coracoid process exists only in a very rudimentary condition, or is altogether absent. The rela- tive disproportion between the supra and infra-spinal spaces is very striking ; usually the former consists only of a narrow plate of bone, but its development in the Camel is more cogent. In Bovidae the root of the spine is blended and continuous at its acro- mial end with the anterior scapular border. The humerus, according to its thickness and bulk, affords a very fair criterion of the comparative activity and strength of the different species. In Camelidae and Bovidae this bone is very massive, and the tuberosities * For details, see Art. "Pelvis." are of great size, the lesser prominence being more elevated than the greater in the first of these two tribes, and hollowed out in front by a capacious channel. The linea aspera stands out boldly, and the external and in- ternal condyles are drawn back, as it were, to deepen the olecranon cavity. The tro- chlear grooves and ridges are also well marked. The foramen for the passage of the nutritious artery is generally situated at the commencement of the lower third of the bone ; but a slight variation is occasionally observed. Thus, in regard to its position in the Giraffe, Professor Owen states that the "medullary artery enters the bone at its inner side about the junction of the upper and middle third," while it is added, that in the skeleton preserved in the Museum of Comparative Anatomy at Paris, the vessel enters the left humerus at the point of union of the middle and lower third.* We have found a similar disposition to occur in our example. The foramen enters at the posterior and inner surface of the right humerus, and is situated very near the centre of the shaft ; but in the bone of the left side it is placed further down, as in the Parisian specimen : the opening is likewise rather smaller. The bones of the forearm (Jig. 346. , A. 2, 3) are Fig. 346. Bones of the fore and hind limbs of the Deer. (From Lond. Coll. Surg. Museum.) * Memoir, foe. cit. 522 RUMINANTIA. intimately united, and, being connected to the humerus by a simple hinge joint, are always retained in a state of pronation — as the surface corresponding to the palm of the hand is always directed backwards ; to increase the steadiness and strength of the limb, the upper end of the ulna is very thick, and in the upright position of the animal the articular angle of the olecranon is firmly locked between the brachial condyles. There is a deep groove indicating the radio-ulnar line of union, at the upper part of which is a vacant space, and another is sometimes present near the distal end. In certain individuals the ulna is represented by two distinct pieces, the central part of the shaft having disap- peared. In all cases the olecranon is ex- tremely prominent, and the bone is relatively much longer than the radius. There is no vacant interval between the bones in the Camel, which together acquire an extra- ordinary length. The radius and ulna in the Javanese musk are nearly of equal bulk, and the line of attachment is very distinct through- out. In a specimen preserved in the Edin- burgh College of Surgeons' Museum, the bones of the right side are anchylosed only at the middle of the shaft. All ruminants possess six carpal bones (k.fig. 346.), and some have seven, which are disposed in two rows. In the upper may be recognised the os scaphoides (4), os lunare (5), os cuneiforme (6), and os pisiforme (7) ; in the lower the os trapezoides (8) and os magnum (9), and in the Giraffe and Camel the os unci- forme (c, a.). The metacarpals are represented by a central cannon bone (10), and in the Deer- tribe and Antelopes by two additional rudi- mentary splint-like pieces, which are separated from the lower and back part of the former by the intercalation of four ossa sessamoidea. Fig. 347. ection of the cannon lone. (From Lond. Coll. Surg. Museum.) The large central shaft or cannon is in reality composed of two metacarpals, as can be readily demonstrated by making a longi- tudinal section, such as is displayed in the annexed woodcut {Jig. 347.). In this view the duplicity of the shaft is shown by the thin lamina of compact osseous tissue (d), traversing the hollow cylinder from end to end ; and its duality is further evinced by the bifid character of the distal extremity (a, £), as well as by a deep median furrow at the posterior surface. The two splint bones are homologous with the metacarpals of the index and little fingers in the human subject. They are not present in all ruminants ; but in the Deer they attain a considerable size, and support two small digits. In some cervine species these styliform metacarpals are seen attached at both extremities of the cannon bone. In the genus Moschus they are as long as the shank, forming thus a transition to- wards the four-toed pachydermata. Six phalanges enter into the composition of the cloven foot, the two upper being the longest, and having a position analogous to the pastern bone of Solipeda; the superior arti- cular surfaces are deeply grooved for the re- ception of corresponding ridges (fg.Skl.c, c), surmounting the trochlear facets of the can- non bone. The second pair are short, the distal end presenting an extended convex plane for the hinge movement of the ulti- mate phalanx. A sasamoid bone is some- times seen behind this joint. The last pair are more or less triangular, and their com- bined plantar surfaces form a semicircular disc, resembling that of the coffin bone of the Horse. In those genera which have super- numerary digits, the rudimentary phalanges do not, under ordinary circumstances, reach the ground; and though invested with a hoof- like covering, they can but slightly aid in supporting the weight of the body. In the Rein-deer, however, as Sir Charles Bell ob- serves * " these bones are strong and deep, and the toe, by projecting backward, extends the foot horizontally, thus giving the animal a broader base to stand on, and adapting it to the snows of Lapland, on the principle of the snow-shoe." The same observation ap- plies, though in a more limited sense, to those species where the lateral toes are less conspicuously developed, in which case the elasticity and firmness of the spring will be heightened when bounding through weedy thickets and on grassy moors. Bones of the posterior extremity. — The hind and fore limbs are not of equal length, and if the actual extent of the individual bones be added together, the balance will be found in favor of the posterior limb. This is evident at a glance in the genus Moschus, and in the Giraffe there is no ex- ception to this rule. In order to make our position clear, the following relative ad- measurements are deciphered from personal examination : — * Briclgewater Treatise, "On the Hand," p. 93. RUMINANTIA. 523 Dromedary Javanese Musk Bed Deer - Rein Deer - Fallow Deer Irish Elk - Goat - 62 32 27 51 19 Fore limb. Hind limb. 62 inches 65 inches 38 " O0<% jj 34 ., 60 „ 48 I It will be remarked that the proportionate difference, as here indicated, is much less in the Arabian camel than in the more typical ruminants. The femur (fig. 346. B. 1 ) resembles for the most part that of other mammifera, being characterised by a rather short shaft and neck, and having the head placed nearly in a line with the longitudinal axis. The great trochanter is prominent, and forms the highest point when the limb is placed in an upright position. The inter-trochanteric fossa is capacious. The bone presents at the inferior end an extended articular surface, and bulges at the forepart, where it is deeply grooved for the patella and tendon of the quadratus muscle. Behind the external condyle is a hol- low, and its rough outer margin is continuous with the faintly indicated linea aspera. In the Giraffe the distal extremity of the thigh- bone attains a prodigious development. The nutritious artery enters at the anterior aspect of the cylinder a little below the cervix, as in other keratopherous ruminants ; we have also observed the arterial foramen of the left side to be about half an inch lower than on the right, an arrangement analogous to the devia- tion noticed in connection with the humerus of this species. The] patella (d) is comparatively small and compressed laterally ; it is sharp in front, and the applied surface exhibits two well marked facets. The tibia (2) is the longest bone of the hind leg, and is chiefly remarkable for the prominence of its spine, which projects from the upper fourth of the shaft and presents a sharp ridge directed outwards. A long styli- form fibula is stated to exist in Moschus, which is united to the external border of the tibia. In the Javanese Musk preserved in the Edin- burgh College of Surgeons Museum, there is no appearance of this bone. Slight traces of the fibula, however, are met with in other cervine genera, in the form of small osseous nodules jutting from the head of the tibia, and in some of the Deer tribe there is likewise to be noticed a small bone constituting the external maleolus (fig. 346, D A. 3). This supplementary piece is, in all probability, the representative of the lower end of the fibula, and it is articulated by three distinct facets to the tibia, os calois, and the astragalus. The bones of the tarsus, properly so con- sidered, are five in number, viz., — os calcis, (2) and os astragulus (5), two ossa cunei- formes (8), and a single mass (9) resulting from the union of the os scaphoides and os cu- boides. In the Giraffe and in certain Antelopes and Deer the two cuneiforms are conjoined. The bone of the heel is in all much elongated. In Camelidae the scaphoids and cuboids (D 4? and 9) are disconnected. In conformity with the disposition of the metacarpal bones in the anterior limbs, the metatarsals form a single cannon bone pos- teriorly (10). More evident traces of ori- ginal duplicity are observable in the latter, than in the corresponding cylinder of the fore-limb, owing to the presence of a fur- row in front in addition to the one placed behind ; the latter groove being moreover particularly deep. In Cervidae and Ante- lopidae, splint-bones homologous with the metatarsals of the second and little toes of the human subject are occasionally present, to support two supernumerary digits as obtains in the fore-leg; but these spurious phalanges are sometimes seen without the styliform appendages. In Moschus the rudi- mentary metatarsals acquire a much greater significance, extending upward nearly as far as the tarsus (c, fig. 348.). We have already JFig. 348. Bones of the hind limb of Moschus. (From Lond. ColL Surg. Museum.) alluded to a similar peculiarity in the meta- carpus of this aberrant genus. The disposi- tion of the true digital phalanges and their accompanying «ssa sessamoidea simulates in every respect that displayed in the con- struction of the cloven foot of the anterior extremity. MYOLOGY. — The muscles of ruminants ex- hibit few peculiarities apart from those of quadrupeds generally. They present arrange- ments very similar to those seen in Solipeda, and in the article devoted to the considera- tion of that group, numerous comparisons have been instituted in reference to the more important myological deviations found in this order. Selecting principally the Ox and Sheep as types, we have to offer, in regard to this great system of motary organs, the following particulars : — Panniculus carnosus. — Traces of this super- ficial muscular investment exist over the whole surface of the trunk, but in certain localities the fibres are more cogent, and form separate bundles, so as to assume more or less the character of distinct muscles. Eight 524 RUMINANTIA. or ten such bundles may be remarked in different species. In the first place we have a broad band extending from the fore-part of the neck, and spreading toward the lips and forehead ; this constitutes the musculus cu- taneous faciei. Again, it is very strongly marked at the neck, especially in the Sheep ; here it is denominated the m. cutan. colli. In other domestic animals of the non-ruminant kind, such as the Dog, Cat, and Pig, this se- cond division of the fleshy envelope is still more striking. Over the shoulder of the Ox there is a third layer of thickened fasiculi (m. cutan. humeri) ; and lastly, we find a highly developed mass, taking its origin from the fascia lata of the thigh immediately above the patella, and proceeding forward, the fibres radiate toward the scapula in front and the abdomen below ; this is the m. cutan. maximus sen abdominis. The insertion of the panniculus is directly into the skin, which everywhere covers it, and " on this texture it can alone act, seeing it is completely isolated from the deeper seated parts, by an universal layer of fascia, which thus enables it to slide more freely upon them. When in action, the fibres throw the skin into folds that form right angles to their general course ; the chief points from which they act being the angle of the jaw, the scapula, the patella, and the pubis."* The principal function appears to be that of serving as an instrument of de- fence. By its action animals have the power of jerking and shaking the skin, thus removing irritating matters, — also of erecting bristles and spines as instanced by the defensive armature of the Hedgehog, — and in aiding the process of lactation, as obtains in the Marsupiatae. Were it not for the constant and involuntary action of the muscle, the torture (to which many animals, particularly cattle, are subjected, from the stings and bites of flies and other insects), would become intolerable, and consequently we find those creatures which are most exposed to their injurious attacks a preponderating de- velopment of this structure. In the same category as the above cutaneous muscles may be associated themusculus prepu- tialis sen umbilicus, the superficial orbicularis palpebrarum, and certain of the complicated set of organs which act upon the concha and scu- tum of the external ear. Of the latter, sixteen pairs have been described as common to the Ox, and nearly as many have been indicated in the Sheep. In both genera they surround the ear on all sides, and offer similar characters in respect of relative size and position. By their reciprocal action the auricular appendage is turned in every direction, as well as rotated upon its own axis ; it is likewise expanded and contracted by such of them as proceed from one part of the concha to another. The orbicular muscle of the eyelid (5,/g. 349.) is thick and fleshy, and its action is aided above and below by thin strata of fibres coming from the panniculus; these are independent of the ordinary elevators and depressors of the lid. Muscles of the head and trunk. — Referring to the accompanying figures for a general outline of the superficial and deep muscular layers included in the above division, we propose to treat in detail of such muscles as acquire a particular interest in respect of their position or importance in a physiological point of view. In the clavicle-bearing mammals the tra- pezius consists of two parts, — an anterior or clavicular portion, and a posterior or scapular division ; but in ruminants and other quad- rupeds which are unprovided with these bones, the posterior section is alone represented by the trapezius properly so called(10, 1 l,j#g.349). On this account it is comparatively small and restricted in its superior attachments, the fore-part being narrow and connected to the elastic ligament of the neck and the dorsal in portion, which is somewhat shorter and thicker, becoming attached to the spinous Fig. 349. View of the superficial muscles of the trunk in the Ox. (From Gurlt.) 1, orbicularis oris ; 2, levator labii superioris ; 3, zygomaticus ; 4, depressor palp, inferioris ; 4 *, risorius santorini ; 5, orbic. palpebrarum ; 5 *, masseter ; 6, corrugator superciliorum ; 7, depressor auriculae ; 8, 8, 8, deltoides ; 9, sterno-maxillaris ; 10, 11, trapezius; 12, latissimus dorsi; 13, pectoral is major; 14, obliquus externus ; 15, glutaeus maximus ; 16, tensor fasciae latae ; 17, 18, biceps femoris. * Mercer, On the Structure and Uses of the Panniculus carnosus, Med. Gazette, 1840—41, p. 346. 30 »._M 19 18 RUMINANTIA. Fig. 350. 9 525 View of the deep muscles of the trunk in the Ox. (From Gurlt.) levat. lab. super. ; 2, pyramidalis nasi ; 3, buccinator ; 4, depressor lab. infer. ; 5, masseter ; 6, temporalis ; 7, splenius capitis; 8, levat. ang. scap. ; 9, rhomboideus ; 10, serratus major ; 11, caput secundum deltoidei ; 12, scalenus anterior ; 13, caput secund. sterno-maxillaris ; 14, abductor brachii superior ; 15, serrat. post, inferior ; 16,obliquus internus; 17, iliacus internus; 18, gluteus medius ; 19, glut, minimus; 20, glut, maximus ; 21, pyriformis ; 22, levat. caudae brevis ; 23, lev. caud. longus ; 24, coccygeus ; 25, rectus femoris; 26, vastus externus; 27, adductor magnus; 28, semitendinosus ; 29, adduct. tibiae longus ; 30, intertransversales caudae. processes of the anterior six or eight dorsal vertebrae. In the Camel it originates from the posterior half of the cervical ligament and the spinous apophyses proper to the first half of the thorax. It is more limited in the Giraffe, where, according to the investigations of Prof. Owen, " it consists of two pretty distinct portions ; one arises from the trans- verse processes of the fifth and sixth cervical vertebrae ; its fleshy part is thick and strong, hut expands as it passes downwards and backwards, and finally is lost in a strong fascia overspreading the large shoulder joint. The second portion is thin and broad ; it arises from the ligamentum nuchae, and is in- serted into the fascia covering the scapula."* That part corresponding to the clavicular or anterior division of the trapezius in the human subject is widely separated from the muscle just described, and is associated with the cleido-mastoideus and deltoides so as to form a tripartite mass, for which Cuvier pro- posed the name of masto-humeralis. It is the levator humeri proprhts of Stubbs, the commu- nis capitis, pectoris et brachii of some, and the deltoides of others (8,8,8,/g.34-9). In the Sheep and in the Ox it consists principally of two portions with an intervening smaller muscular bundle situated at the centre of the neck, and connecting the clavicular portion of the tra- pezius to the tendon of the cleido-mastoidens. The superior or more superficial belly be- comes implanted into the humerus, while the inferior or deeper division is inserted into the sternum. At their upper attachments the duplicity is very apparent, the broad muscular part being united to the ligamentum nuchae, and the rounded tendon being fixed to the mastoid apophysis. After removing the trapezius, our attention is at once directed to a large broad muscle, which in the human subject is represented by the splenius capitis and splen. cervicis. In the * Memoir, L c. Ox and most other ruminants, the cranial division is alone present ; but in the Sheep, according to the researches of Meckel, there are two portions — an anterior or cranial, which is narrow and insignificant, and a posterior of large size, taking its origin by two bundles from the third and fourth cer- vical vertebrae, to be attached to the trans- verse process of the atlas. In the Camels both may be said to be absent, but there is a small muscular slip, proceeding from the ten- don of the digastricus to be inserted into the occiput, which Meckel thinks may constitute a rudimentary form of the splenius capitis. Beneath the splenius, and often incorpo- rated with it, lies the trachelo-mastoideus, which is feebly developed in ruminants and solipeds, but is of large size in the marsupials and edentate mammals. The great complexus and digastricus colli muscles are united into a sin- gle mass, as in the Horse, and in these animals this compound muscle arises by nine or ten fleshy and tendinous slips — intersected by aponeurotic prolongations — from the third cervical to the second or third dorsal ver- tebrae inclusive. In the Camel there are only seven bundles of origin, and a single long aponeurotic septum, and in the Sheep all traces of the latter are absent. The transversalis cervicis is closely adherent to the trachelo-mastoideus. Separated from the former, there is in some ruminants a muscle, which — corresponding with that por- tion of the sacro-lumbalis in man, called the cervicalis descendens — stretches from between the transverse apophyses of several of the lower cervical vertebrae to the oblique and transverse processes of certain of the dorsal segments. Meckel alludes to this peculiarity in the Horse. The scaleni muscles, three in number on either side, are very long and powerfully developed in the Camel and Giraffe, presenting in the latter, according to Prof. Owen, four distinct masses, which take their origin "from 526 RUMINANTIA. the fourth, fifth, sixth, and seventh cervical vertebrae, and are inserted into the manubrium sterni and first rib." In the Sheep the fleshy bundles are very small ; they also arise from the lowermost four cervical vertebrae ; but in the Camel they are connected to all the bones of the neck, except the dentata, the posterior scalenus being particularly short, and only attached to the last. The longus colli and recti have a similar disposition to those of Man, The former is divided into a superficial and deep portion, the latter division extending as far back as the third vertebrae of the thorax. In the Camel this muscle exhibits an increase of develop- ment proportionate with the elongated neck, its posterior attachment commencing at the body of the fourth dorsal segment. The rectus capitis anticus, major and minory are comparatively insignificant in all ruminants and solipeds. The muscular arrangements at the fore-part of the neck present many points of interest; for example, — the sterno-cleido-mastoideus of anthropotomists is represented in the ma- jority of mammifers by two distinct muscles. The first of these, the sterno-mastoideus or maxillaris, is a slender fleshy band which divides near the middle and fore-part of the neck into two portions, one being inserted a little in front of the angle of the lower jaw, and the other becoming attached to the mastoid process. In the Sheep the anterior tendon extends as far forward as the zygo- matic arch, and immediately behind the jaw the muscle is united to the deltoides, beneath which it is also connected to the rectus capitis anticus major by an intervening ten- don. In the Camels this muscle is fleshy throughout its entire extent, and at the lower part is joined to its fellow of the opposite side ; superiorly, its tendons are fixed — one to the mastoid process, and another to the maxilla over the region of the submaxillary gland. The characters and position of this muscle are precisely similar in the Giraffe. The situation of the cleido-mastoideus has been already indicated in the description of the tripartite deltoides. Hyoid apparatus. — Before noticing the muscles connected with the os hyoides it is necessary to direct attention to its osseous framework. The hyoid bone is made up of a congeries of ossicles more or less consolidated, having relation to totally different parts of the ske- leton, but here associated together for the threefold purpose of supporting the tongue and larynx, and affording a point d'appui for the muscles destined to act upon these organs. In the ruminant, as in Solipeda, nine distinct elements may be recognised, arranged in four pairs, the ninth piece being represented by the body or basi-hyal bone. Fig. 351. indicates the relation of these parts in the sheep. Com- mencing from above, the first pair — the styloid bones — or stylo-hyals (1, 1) are seen to have an enormous longitudinal development, being also somewhat hammer-shaped and com- pressed laterally, to favour muscular attach- ment. Their peculiar figure is due to the Fig. 351. Hyoid bones of the Sheep. (From Lond. Coll. Surg. Museum.) presence of two apophyses at the temporal extremity (a a, b b) and it is by the superior process that the bony chain is connected with the cranium. In the Horse these bones are proportionally longer, but they are shorter in the Camelidae than in the typical ruminants. In Man the styloid processes of the temporal are homologous with the stylo-hyals. The second pair or epi-hyals (2, 2) are intercalated between the first and third series of ossicles, and complete a right angle, formed by the relatively horizontal and vertical position of those bones ; they have an insignificant ap- pearance in most of the genera, but attain in the Camels a considerable size. More than two nodules are sometimes present. The epi-hyals are most conspicuous in the carni- vorous mammifers, but in the human subject are merely represented by two long liga- mentous bands, which in a few instances have been found ossified. The third pair or cerato- hyals (3, 3) have a nearly vertical position when the head is raised, and they constitute with the epi-hyals, the lesser cornua which in Man are feebly indicated, being recognised only by two small pisiform nodules moveably articulated to the body of the hyoid, and forming, as in the present instance, a right angle with the greater cornua. In the typical ruminants these elements are larger than the epi-liyals, but in the Dromedary, according to Duvernoy, this character is reversed. The body of the hyoid or basi-hyal (4), of a tri- angular form, is placed below the cerato- hyals and anterior to the greater cornua, the four ossicles of which they together consist, being articulated to the extremities of its lateral apophyses on either side. There is generally a slight bulging at the anterior and middle part, indicative of the tendency to antero-posterior elongation, which feature becomes very manifest in other vertebrata, and more particularly in birds ; it is to this point that an additional element — the true lingual bone or glosso-hyal — is connected, in RUMINANTIA. 527 many of the avian and piscine families, traces of it also appearing in Solipeda and other quadrupeds ; it is remarkably large in the Bear. In Camelidae the basi-hyal presents no anterior protuberance. The fourth pair or thyro-hyals — hypo-branchials of fishes and amphibia— (5, 5) represent the greater cornua of the anthropotomist, but in certain mam- mifers, as in the family under consideration, their extent of development is subordinate to that of the lesser horns. In birds, on the other hand, the length of the thyro-hyals is extreme, the lesser cornua being either rudi- mentary, or altogether absent.* The muscles proper to the hyoid chain of bones present many interesting modifications. The sterno-hyoids and sterno-thyroids (which in Man and mammifera generally, remain distinct throughout their entire extent), are united below in the majority of ruminants, their com- mon band of origin dividing near the middle of the neck, the larger division being connected to the hyoid bone. Meckel states that the sterno-hyoid is entirely absent in the Camel, and Duvernoy remarks the same peculiarity in the Sheep ; but Gurlt figures the upper part of it in the latter animal and in the Ox. A muscle analogous to the omo-hyoid presents a remarkable difference of origin, relatively, in the typical ruminants, the Camel and the Giraffe. In the Sheep it originates, according to Meckel, in the form of a muscular band of considerable dimensions, which is given off by the rectus capitis anticus major, and leaves that muscle at a point corresponding to the third cervical vertebra to be inserted into the hyoid immediately behind the attachment of the thyro-hyoid muscle. Its relation in the Giraffe will be reverted to presently. In the Camel the disposition of this structure is ex- tremely complicated. From the researches of Meckel we learn that it arises from the anterior division of the transverse process of the fourth cervical vertebra, and is confounded near its commencement with the lowermost bundle of the straight anterior muscle of the head ; it subsequently divides into three por- tions, the first becoming inserted into the lower lip, the second going to the posterior cornua of the hyoid, and the third attaching itself to the lower jaw, upon which it acts as a powerful depressor. Professor Goodsir has remarked to us that an anomaly analogous to this latter distribution is sometimes seen in the human subject. The stylo-hyoid, which is absent in certain Carnivora, its place being sup- plied by a narrow muscle termed the ceratoido- lateralis, is present in the Ruminantia, where the latter muscle appears as a prolongation of the stylo-hyoid rather than as a'distinct muscle. The first of these two muscles — regarding them as such — proceeds by a long tendon from the posterior and inferior apophysis of the styloid bone, to be attached below to the base of the thyroid cornua ; the ceratoido- lateralis also descends obliquely from the lesser horn to the greater. In both the above- * Sea art. TONGUE. named families and in the Pachydermata there is likewise a special muscle termed the maslo- styloid ; it is short and triangular, and, arising from the mastoid process of the temporal bone, becomes inserted into the inferior apo- physis of the hammer-shaped extremity of the stylo-hyal element or styloid bone, immediately above the origin of the tendon of the stylo- hyoid muscle. The mylo-hyoid is distinctly double, the anterior bundle having an extended longitudinal development, while the posterior division is short, and has its fibres directed transversely outward. The genio-hyoids of either side are incorporated at the middle line. In the foregoing description of the muscles connected with the hyoid apparatus we have intentionally omitted those of the Giraffe, pre- ferring, on account of the peculiar interest which the muscular arrangements of this ani- mal present, to treat of them separately. We quote at length, therefore, from the accurate researches of Professor Owen.* " The mylo- hyoideus is a thick and strong muscle , it arises from the whole of the internal surface of the lower jaw, and is inserted principally into the raphe, or longitudinal commissure, dividing it from its fellow of the opposite side. It adheres firmly to the genio-hyoideus : this arises by a well marked tendon from the posterior rugous surface of the symphysis menti, and has the usual insertion. The genio-glossus arises by a tendon close to the inner side of the tendon of the genio-hyoidew ; its fleshy belly has a considerable antero- posterior extent, and diminishes to a very thin edge at its anterior margin. The digas- tricus has the usual origin, and is inserted, broad and thick, into the under side of the lower jaw. The stylo-hyoid is external to the digasiricus, and is remarkable for the slender- ness and length of its carneous part. The most interesting modifications in the muscles of the os hyoides were found in those which retract that bone. The muscle which, as in some other ruminants, combines the offices of the sterno-thyroideus and sterno-hyoideus, arises in the Giraffe by a single long and slender carneous portion from the anterior extremity of the sternum ; this single fleshy origin is nine inches long, and terminates in a single round tendon, which is six inches long ; the tendon then divides into two, and each di- vision soon becomes fleshy, and so continues for about sixteen inches ; then each division again becomes tendinous for the extent of two inches, and ultimately carneous again, when it is inserted into the side of the thy- roid cartilage, and is thence continued in the form of a fascia into the os hyoides. We have in this alternation of a contractile with a non- contractile tissue a striking example of the use of tendon in limiting the length of the car- neous or contractile part of a muscle to the extent of motion required to be produced in the part to which the muscle is attached. Had the sterno-thyroideus .been continued fleshy as usual from its origin through the * Memoir, I. c. p. 232. 528 RUMINANTIA. whole length of the neck to its insertion, it is obvious that a great proportion of the mus- cular fibres would have been useless; for as these have the power of shortening themselves by their contractility only one-third of their own length, if they had been continued from end to end in the sterno-thyroidei, they would have been able to draw the larynx and os hyoides one-third of the way down the neck ; such displacement, however, is neither required nor indeed compatible with the me- chanical connections of the parts ; but, by the intervention of long and slender tendons, the quantity of the contractile fibre is duly appor- tioned to the extent of motion required for the larynx and os hyoides. The muscle ana- logous to the omo-hyoideus of other animals, is adjusted to its office by a different and more simple modification ; instead of having a remote origin from the shoulder-blade, its fixed point of attachment is brought forward to the nearest bone (the third cervical ver- tebra) from which it could act upon the os hyoides with due power and extent of con- traction. Its insertion is by a small round tendon." The muscles of the back and tail present few deviations worthy of remark. The spin- alls and longissimus dorsi exhibit the same attachments as in Solipeda. The sacro-lum- balis is proportionately strong in ruminants. The semispinalis colli, according to the ob- servations of Meckel, is very largely developed in the Camel, originating from the spinous apophyses as well as from the transverse processes of the five or six anterior dorsal vertebrae. These additional points of origin, while they afford a greater leverage power, constitute at the same time an important pe- culiarity in this long-necked animal. The diaphragm, which is present in all mam- mifera, exhibits three openings for the passage of the aorta, oesophagus, and inferior vena cava. A very remarkable feature exists in connection with this muscle in the Camelidae. It consists in the presence of a small bone situated near the margin of the central tendon. Meckel states that Dr. Jceger was the first to direct attention to this anomaly in the Dromedary and in the Vicugna*, the observation being subsequently confirmed by Dr. Leuckart and himself. In the two-humped orBactrian Camel its presence was overlooked by the original discoverer, but afterwards ascertained by Meckel to oc- cur in this species also. The bone offers slight variations according to the age of the individual ; it is thin and rather more than two inches long in the adult Camel ; in the Vicugna it is but feebly developed. Its so- lidity is not acquired until a late period, for, in a Dromedary about two years old, the car- tilaginous matrix only was discernible. In conclusion it may be said that this osseous formation is apparently designed to give sup- port to the diaphragm, which is of great bulk in these animals. * Syst. der vergleich. Anat, (Fr. edit., torn. vi. p. 212.) Muscles of the shoulder and fore-limb. — The trapezius has already been considered. The levator angnlis scapulce (&,fig. 350.) varies little from the ordinary mammiferous type. The rhomboideus (9) is usually represented by two muscles, r. minor and r. major; the former, sometimes called the superior, arises in the Sheep from the ligamentum nucha? as far forward as the second vertebra of the neck, and the latter, or rhomboideus inferior, proceeds from the spines of the first two or three dor- sal vertebra?, the fibres of both converging to be inserted into the upper border of the sca- pula. In the Horse the muscle is single, and extends forward to the occiput, but is only connected superiorly to the cervical ligament. It is very feebly developed in the Camel, pass- ing only from the spines of the two anterior dorsal vertebra? to the posterior angle of the scapula. In certain Pachydermata and in the Cetacea its appearance is still more insig- nificant, but it is particularly large in the carnivorous mammals and in the Ornithorhyn- chus. In the Giraffe it is inserted, like the largely developed serratus major, into the car- tilage surrounding the base of the scapula; and in reference to the use of this structure Prof. Owen observes that " as the fore-part of the trunk is, as it were, slung upon the two great serrati muscles which principally support the weight of the remarkably deep chest of the Giraffe, the interposition of the elastic car- tilages between the upper attachments of the muscles and the capitals of the bony columns of the two fore-legs, must be attended with the same advantage as is obtained by slinging the body of a coach upon elastic springs." * The serratus magnus or major (10, 10) is ex- ceedingly strong in this order. In quadrupeds generally, it differs from the human subject in presenting a cervical attachment in addition to its costal connection. In the Sheep it has no less than thirteen bundles of origin, eight of which come off from a corresponding num- ber of the superior ribs, the remaining five proceeding from the transverse apophyses of the third to the last cervical vertebra inclu- sive. In other ruminants there is a slight numerical variation in regard to the fleshy digitations, but their general disposition is the same, being in all cases subsequently united and implanted into the base of the scapula, there forming, in conjunction with the tra- pezius, a sling-like support to the anterior extremity. The serratus minor has an ar- rangement in mammifera similar to that of its anologue, the lesser pectoral of the human subject ; but in the latter it is inserted into the coracoid apophysis of the scapula, while in the former it is usually connected to the humerus. In many carnivorous, edentate, and marsupial families this muscle is entirely wanting. The latissimus dorsi (12, fig. 349.) is some- what feebly developed in ruminants, but its attachments are similar to those in Man. The pectoralis major (IS, Jig. 349) is proportionately * Memoir, L e. RUMINANTIA. 529 greater, and divided into two,— a small fleshy bundle proceeding from the anterior extremity of the sternum to the lower part of the htimerus, and a larger mass coming off from the whole length of the sternum pos- terior to the former, its fibres passing ob- liquely forward to be inserted into the external tuberosity of the same bone. There is an ad- ditional muscular slip in the Sheep and Horse, by the action of which the crossing of the fore-legs is produced ; this is denominated by hippotomists the ambibrachialis counnunis. Cu- vier remarks the same muscle in Cetacea. Corresponding to the scapular division of the deltoid in the human subject, there is, in ru- minants and solipeds, a muscle called the ab- ductor longus brachii or abcL brack, superior (14, fig. 350.) ; it generally exhibits two points of Fig. 352. Superficial layer of muscles of the fore limb of the Ox. (From Gurlt.) 1, supra-spinatus ; 2, infra-spinatus ; 3, abductor brevis ; 4, anconeus longus ; 5, exten. cubiti lon- gus ; 6, ancon. externus ; 7, brachialis interims ; 8, deltoides ; 9, 9, exten. carpi radialis ; 10, ab- ductor pollicis; 11, 11, extensor digit, longior; 12, 12, exten. digit, brevior; 13, 13, flexor carpi ulnaris exteruus. attachment above, one at the spine of the scapula, and the other from the infra-spinous fossa. On their passage down, the fibres coalesce, and become inserted by a common tendon into the linea aspera of the humerus. The external scapular muscles, viz., the supra- Snpp. spinatus (l,fg. 352-) and infra- sjnnatus (2), are powerfully marked in this order ; the former is implanted by a double tendon of insertion into the anterior and internal tuber- osities of the humerus, the latter being con- nected below to the external tuberosity. The round muscles have the same attachments as in man, but the teres major or t. externus (3, fig. 353.) is in Ruminantia arid Solipeda smaller than the teres minor or t. interims (2, Jig. 353). The sub-scapularis (2, 2 fig. 353.) is of large size, and subdivided. The coraco-brachialis (&,fig> 353.) is always present, although there be no indication of a coracoid apophysis ; the greater part of the muscle lies deep, and is connected to the inner border of the upper half of the humerus, the remainder lying more superficially, and continuing as far as the internal condyle into which it is implanted. The biceps brachii coraco-radialis or flexor cubili longus (10, fig. 353.) has a similar disposition to its analogue in Man ; but in Carnivora and Solipeda, where the coracoid process is absent, it exhibits but one head. In the Bear, according to Cuvier, the absent division is represented by a mus- cular slip passing off from the coraco-brachi- alis. Meckel states that in the Camel and Dromedary the apparently single tendon of origin arises from the margin of the glenoid cavity as usual, but it is very thick, and can easily be separated into two portions, which are united only by cellular tissue. These, as they pass over the head of the humerus, swell out and enclose between them a sesa- moid body consisting of nbro-cartilage ; the external of the tendons is the larger, and also subdivides, giving off a strong tendinous cord which becomes incorporated with the anti- brachial aponeurosis. The brachialis internus, or flexor cubiti longus (7, fig. 352, and 11, fig. 353.), is comparatively weak. In the typical ruminant it rises from the posterior and ex- ternal part of the neck of the humerus, but in the Camel it commences lower down from the middle third of the bone, its tendon of inser- tion in all cases being anterior to that of the long flexor. The divisions of the triceps ex- tensor cubiti are described under different names by hippotomists, but this disposition is similar to that of Man. The extensor cubiti longus (5,^.353.) is the extensor magnus of Bourgelat ; the extensor brevis is the extensor medius of the same author, and the anconeous longus of Gurlt ; the brachialis externus is the extensor brevis of the former and the anconeus externus of the latter. There is also another muscle termed by Gurlt the anconeus internus (7,./?g. 353.). The Ruminantia and Solipeda are generally described as possessing neither supinators nor pronators, but the above-named author figures in the Ox a small muscular bundle, which he calls the pronator teres (13, fig. 353.) ; and moreover Meckel points out the rudiments of this muscle in the Camel, remarking at the same time that its function is no longer that of a pronator but of a flexor. The extensor carpi radialis (9, fig. 352.) is single in the Ca- M M 530 melidae, as in the Horse, rising from the ex- ternal condyle and inferior fourth of the hu- Fig. 353. RUMINANTIA. to be implanted into the base of the distal phalanges of either toe. Muscles of the haunch and hind-limb. — The glutens maximus (15, fig. 349.), which is but feebly manifested in all quadrupeds, owing to the horizontal position of the body, has an in- significant development in ruminants. It rises from the crest of the ilium and sacral fascia, receiving in its passage down a strong tendon from the tensor fascice lat^» While the growth and condition of thecuti- into the base of the ultimate bones of the cular layer of the skin in the different classes toes, and those of the latter into the distal extremities of the penultimate phalanges. A muscle corresponding to the abductor pollicis (10) is present, notwithstanding the absence of the thumb, and becomes attached to the inner aspect of the inferior end of the cannon bone. Thefiexores carpi ulnaris externus (13) and internus (16, fig. 352.) are both inserted into the pisiform bone. The tendons of the fiexor digitorum sub Urn is (\5,fig. 352.) and of the Jlcx. dirit. profundus pcrforans remain dis- tinct, the latter piercing the former as usual, Deep layer of muscles of the fore-limb of the Ox, viewed from within. (From Gurlt.) 1, supra-spinatus ; 2, 2, subscapularis ; 2*, teres minor ; 3, teres major ; 4, latissimus dorsi ; 5, ex- tensor cub. longus; 6, anconeus longus; 7, an- con. internus ; 8, coraco-brachialis ; 9, pectoralis major ; 10, biceps brachii ; 11, brachialis internus ; 12, extens. carpi radialis ; 13, pronator teres ; 14, flexor carpi radialis ; 15, flexor digit, sublimis ; 16, flex, carpi ulnaris internus. merus to be inserted into the base of the can- non bone at the fore-part. Antagonistic to this, is the flexor carpi radialis (14-, fig. 352.), the tendon of which is connected to the base of the cannon bone behind. The tendons of the extensor -es digitorum longior (11) and bre- vior (12, fig. 352.) separate in front of the foot, the divisions of the former being inserted of ruminants is of the highest importance in an economic point of view, it is not the less certain that the phases of development through which the integumentary covering passes — its varied aspect and periodicity of renewal, together with the causes which in- duce such changes — are matters of high in- terest to the physiologist. In no group of mammiferous quadrupeds have we a more striking example of the adaptation of structure to the exigences of the creature than obtains in the remarkable dorsal RUMINANT1A. 531 nump, and in the cushion-like sole-pad of the Dromedary. The hump consists essentially of adipose matter, developed in the subcutaneous areolar substance, its secreting cells having undergone an extraordinary local increase. To support such a mass, the connecting tissue exhibits a corresponding augmentation, the fibres assum- ing the character of ligamentous bands, which are firmly united below to the capitals of the bony columns of the dorsal vertebrae. In reference to the function of this growth tra- vellers have ascertained beyond all contro- versy that it serves as a store-house of nourishment, affording to the animal, in con- junction with the stomachal water-cells, a pro- vision against the inanition which long jour- neys would otherwise entail. In accord with this statement, it has been observed that the hump of the Dromedary becomes attenuated and reduced under circumstances of impover- ishment, while, on the contrary, it is marked by rapid increase and ultimate plumpness when the supply of food is abundant. The general character of the dermal en- velope in Camelidae deserves little comment ; the hair is coarse and shaggy in the typical species, and of a soft woolly texture in the Auchenias, where it is also very long. At certain points it acquires in the Camel a rigid bristle-like character, this being especially manifest at the under part of the feet, near the margin. In this spot, however, the hairs are scanty, and they are entirely absent for a small space, over the so-called knees, and at the under and fore-part of the chest, where from constant pressure during the recumbent posture of the body, the cuticle acquires a horny consistency. These callosities are not present in the Llama. One of the most interesting anatomical features, forming a distinction between the two cameline genera, consists in the degree of organisation of the foot-pad and corneous in- vestment of the toes. In the Camels, properly so called, the digits are more or less com- pletely imbedded in the broad elastic cushion which extends for a considerable distance laterally on either side of the foot, binding and fixing the phalanges immoveably together ; while at the same time it is particularly worthy of remark, that the hoofs are merely repre- sented by two rudimentary nails situated on the dorsal surface of the tip of each toe. In the Llamas the sole-pad is double and narrow, each division being limited to one side of the cloven foot, while the nails, instead of being weak, are very powerfully developed, and strongly curved. In consequence, therefore, of the easy separation of the toes, combined with the modifications of the pad and hoof here referred to, it is at once evident that such a condition of the foot is peculiarly adapted to an animal whose life is destined to be spent, unlike that of his more highly valued congener, on the rugged slopes and precipices of a mountainous district. In the solid-horned Ruminantia very im- portant changes coexist with the shedding of the antlers. These organs occupied our at- tention when describing the anatomical rela- tions and development of the horns ; but, as some physiologists are disposed to regard them as part of the dermo-skeleton, we take this opportunity of reverting to the subject. If such a view as the one here mentioned be not supported by the mode of growth, it ac- quires nevertheless an appearance of consist- ency when we bear in mind that the annual shedding of the horns takes place contem- poraneously with that of the hair. By others, this simultaneous loss of structure is regarded as a mere coincidence, affording no proof, they say, of the integumentary character of the cranial outgrowths, but rather indicating a special provision, for the explanation of which we are to look to another source. This ar- gument is followed up by assuming that, were it not for the change alluded to, the young Deer would sustain injury from the bucks, which, at the period of the full evolution of the antlers, exhibit a destructive and relentless ferocity. After the loss of the offensive wea- pons, it is well known that their disposition acquires a milder habit. In furtherance of this view of the question we are likewise re- minded that it is necessary to associate the persistency of the horns of the Giraffe with the equally well ascertained fact, that in this aberrant cervine genus, there is, as in Cervidas proper, a periodical desquammation of the cuticle not affecting the hairy covering of the cranial epiphyses, and involving no subsequent alteration in the animal's psychical character, which, under ordinary influences, is proverbially gentle, and always the same. In a former part of this article, reference has been made to the epidermic nature of the corneous investment of the bony cores in cavicornua, and the extension of it found pro- longed over the frontal region in the Buffaloes, a tribe exhibiting an approach to the Pachy- dermata in many respects, and more especially in the organisation of the hide, which has a leathery consistence, and is scantily provided with stiff bristly hair. In conclusion we may remark that the cloven condition of the hoof in the typical ruminant is evidently designed to impart light- ness and elasticity to the spring ; and, in order Fig. 354. Foot of the Sheep. MM 2 532 RUMINANTIA. to give full effect to such an arrangement, many species are provided with a special glandular sebaceous follicle between the toes, whose office is to furnish a lubricating secre- tion, calculated to prevent injury from friction of the digits one against the other. Fig. 354*. represents the position and dimensions of this organ in the Sheep. According to Sir Charles Bell there is yet another intention in this cloven form, viz., that of aiding the voluntary eleva- tion of the foot when it has sunk deeply into soft ground. " We may observe," he says, " how much more easily the Cow withdraws her foot from the yielding margin of a river, than the Horse. The round and concave form of the Horse's foot is attended with a vacuum or suction as it is withdrawn ; while the split and conical shaped hoof expands in sinking, and is easily extricated."* DIGESTIVE SYSTEM. — Buccal Cavity. — The lining mucous membrane of the oral cavity is very rough, being covered throughout with very prominent papillae. At the roof of the mouth they have a flattened form, and are arranged in parallel rows, producing a series of ridges or bars, the margins of which are den- ticulated and directed backward. They are very conspicuous in the Camel, and in the Giraffe we have counted from fourteen to eighteen rows ; the papillae of the anterior ridges, however, lose much of their linear arrangement. Respecting the use of this pe- culiar grooved structure, Mr. John Zaglas appears to have offered a satisfactory solu- ion. Speaking of the action of the tongue during deglutition, he says, " I may here hazard the opinion, that the transverse rugag on the palate of Man and the lower animals are intended, to a certain extent, for the sup- port of the tongue in the act of elongating itself backwards. The varieties which they exhibit coincide with what would appear to be required in the relations of the tongue and oral cavity. In Man, in whom the alveolar process is perpendicular, they are slightly de- veloped, and situated far forward. In the lower animals, in which the alveolar process is small or oblique, the rugae are situated farther back, and are more full}' marked, par- ticularly in those which swallow bulky arid comparatively rough morsels, as in the ru- minants and solipeds." f The oral roof of the Giraffe is marked by an extensive deposit of leaden-coloured pigment, stretching from the alveolar margin to the centre of the palate ; small isolated patches also occurring still far- ther back. A callous thickening of the gum occupies the place and supersedes the function of the non-developed intermaxillary incisives. The buccal papilla? attain their greatest size in the region of the cheek opposite the true mo- lars. In this position they take on the cha- racter of horny spines, very like those seen in the oesophagus of the Turtle. They have either the form of simple elongated cones, or are aggregated together, and blended so as to * Bridgewater Treatise, p. 92. f Goodsir's Annals of Anatomy and Physiology, Part II. p. 122. present two, three, or even four points. This complicated disposition is well shown in the ac- companying figure (fig. 355.)from the Camel ; in Fig. 355. Buccal papillce of the Bactrian Camel, (From F. Miiller and Wedl.) the Giraffe the longest spines, which are fully half an inch in length, give off secondary processes, thus resembling very closely the fungiform pa- pillae of the human tongue after the epithelial layer has been removed. Professor Owen is of opinion that the principal function of these organs consists in adjusting the bolus during mastication. Teeth. — Consistent with the compound character of the ruminant stomach, a parallel complexity obtains in the structure of the teeth, at least, in those concerned in tritu- rating the food. In those families which have incisives in the lower jaw only, these exhibit simple trenchant crowns, which slant horizontally forward ; and being opposed only by the hardened gum of the upper jaw, the function they perform during the act of feeding is rather that of breaking or tearing, than cutting. The action is accompanied by a swinging movement of the head forward, the powerful muscles in- serted into the occiput along with the elastic ligamentum nuchae, rendering such a motion almost effortless. In (Egosceridae, Bovidae, and Cervidse generally, where the incisors form a broad line at the expanded tip of the lower jaw, the extent of their grasp is considerably increased by the prominent position of the canines on either side. These latter partake of the function ascribed to the former, and their aspect is so similar that many ana- tomists have been led into error respecting their true nature. In the Giraffe the canines present divided crowns, and are not placed so far in front ; nevertheless, they are closely applied to the outer incisors, the whole series together forming a semicircle. The characters of the molar teeth chiefly demand consideration in this place. These, though presenting every variety and modifi- cation of contour in the different families, manifest at the same time a certain uniformity of type throughout the entire order. A sin- RUMINANTIA. 533 gle example will illustrate the points most deserving of attention. The true molar tooth of the permanent series has a quadrilateral form, its outer and inner lateral surfaces being bounded by mar- gins more or less convoluted. The crown in the young state presents four elevated cusps, which, by subsequent attrition, disappear. The ground surface, thus flattened, is marked in the centre by double crescent-shaped ridges of enamel, so disposed as to present, along with the central mass of dentine and external crust of cemctitum, alternate layers of hardened tissue, having different degrees of density. By such an arrangement it conse- quently follows that the enamel being the least affected by trituration, remains some- what above the level of the other dental sub- stances,— a condition highly favourable for the due performance of mastication, and one re- sulting in all cases from the vertical folding of the original formative capsule. The upper molars of certain individuals present an ac- cessory island-shaped portion of enamel at the internal border, by which the extent of grinding surface becomes enlarged. This additional facet only makes its appearance in a tooth which has been employed for some time, as it depends upon the wearing down of a columnar fold which is developed at the side between the lobes, and which does not extend so high up as the summit of the crown in the unworn tooth ; it is well seen in the Ox and Deer (p, fig. 356.) Fig. 356. Molar tooth of the Deer. (From Owen's " Odontography.") Tongue. — The lingual organ undergoes certain modifications, in accordance with the habits and kind of aliment on which the ru- minant subsists. These peculiarities do not involve any material departure from the type of structure invariably found'in other mam- mifers ; on the contrary, the muscular ele- ments and their relations to surrounding parts remain nearly the same. The deviations of which we have to speak principally refer therefore, to the form of the organ and its epidermal covering. In Ruminantia, more than in almost any other order, the tongue is specially designed to fulfil the offices of pre- hension as well as deglutition, and it neces- sarily follows that the several portions of the machine destined to carry out such com- plicated functions, exhibit a corresponding complexity of development. Those regions, arbitrarily denominated by the anthropotomist the root, body, and tip, acquire great signifi- cance in this group of animals, being mor- phologically indicated on the dorsal aspect of the organ ; and they not only manifest a structural distinctiveness, but the functions over which they preside subserve different purposes. The anterior moiety is employed in collecting, and perhaps in some measure ascertaining the nature of the food ; the second aids in adjusting and preparing the morsel, but is more particularly concerned in thrusting the bolus backward into the oeso- phageal cavity ; while the third circumscribes and regulates the movements of the organ in its entirety, acting from the point cTappui of the hyoid bone (Zaglas). The surface of the tongue is armed with forms of papillae similar to those of Man and other mammalia. Two kinds, namely, the simple^/j/brm and fungiform, are conspicuous and very numerous on the dorsal aspect of the elongated prehensile portion in front, and two other varieties — the conical and circum- vullate — occupy the dorsum towards the root, leaving the inter-molar region com- paratively free. Of those papillae at the fore part, the simple filiform are curved back- Fig. 357. Torgue of the Giraffe. (From Owen.) M M 3 534 RUMINANTIA. ward, and are by far the most abundant of all these structures; they are very closely set together at the tip, and have a horny epi- dermal covering, approaching in this respect the rasp-like retroverted spines on the tongue of Carnivora. The fungiform or spherical gustatory papillae are sparsely scattered here and there, but somewhat closely aggregated at the lingual margins. In the Giraffe, not- withstanding the deposition of a dark purple pigment which distinguishes the anterior half of the tongue, the last named papillae present a very striking appearance, resembling so many small highly polished beads of a deep black colour. They are well shown in the annexed woodcut {fig. 357.). The conical papillae situated behind and towards the root, may be grouped under the same category as the retroverted filiform spines seen in front ; but as they proceed in the direction of the pharynx their conoidal character becomes obliterated, and they assume a more or less flattened oval or rounded form. The papilla rircumvallates, though not occurring in great numbers, are largely developed, and in the Camel exhibit a very complicated structure (Meckel) ; the middle projecting portion, instead of being smooth and single, is split up, as it were, into numerous finely serrated secondary filaments, leaving a small central depression unoccupied, while the elevated circumferential margin outside the circular fossa shows at the same time a tendency to subdivision (by 6, fig. 358). In the Giraffe Fig. 358. Section from the base of the tongue of the Bactrian Camel. (From F. Mtiller and Wedl.) and Deer they offer a faint indication of the central dimple, but their character otherwise accords with the appearances usually pre- sented. The muscles of the tongue, as already hinted, display few marked deviations from the or- dinary mammiferous type ; nevertheless, the comparative glossologist recognises in these slight differences, points fraught with peculiar anatomical and physiological interest. To enunciate this speciality fully in all its bear- ings would demand more time and space than has been placed at our disposal, and it is not without regret that we are compelled to limit the exposition of so captivating a subject to the few following remarks, gathered in great measure from the monograph of Mr. Zaglas and the observations of Professor Owen on the tongue of the Giraffe. For- tunately, we have had an opportunity of con- firming the previously recorded particulars concerning the lingual organisation of this remarkable animal, and in regard to the myological arrangements of the tongue in other ruminants, the writings of Cuvier, Blandin, and others, furnish some important details.* The styloglossus rises from the lowermost extremity of the styloid bone, and extends along the under surface of the tongue as far as the tip, being separated only from the muscle of the opposite side by the interposed genio-glossi. It is powerfully developed in the Giraffe, and is confined in its position by strongly marked bands of muscular fibre di- rected outwards from the superior border of the genio-glossus (where that muscle dips into the medullary substance), to the mar- ginal expansion of the lingual fascia investing the dorsum. This muscle is of small dimen- sions in the Camel. The hyo-glossus is a compound structure, its several portions dif- fering only from those in man by being more distinct and widely separated ; the division recognised as the ccrato-glossus by the human anatomist is usually described as the stylo- glossus minor in the lower animals. The genio-glossus varies considerably in size, and is unconnected with any part of the hyoid apparatus (Blandin) ; ordinarily, the laminae of each muscle are easily parted in conse- quence of the looseness of the interposed areolar substance as far as the mesial line, where the fibres begin to dovetail into one another. In Man the fasiculi are short and comparatively thick, but in the Deer and Camel the two muscles are thin and united anteriorly. These applied muscular laminae are very strong, and have a great longitudinal extension in the Giraffe ; posteriorly they admit of easy separation, but in front the fibres are intermixed, attenuated, and with difficulty isolated. In connection with this part of the subject it may be remarked that the researches of Mr. Zaglas have shown the septum (line a albesccns of Caldani) or car- tilago-lingualis to have no real existence in the Sheep, Deer, Calf, or Camel; and we may add that our own examinations prove that this structure is likewise absent in the Giraffe. The value of this observation is enhanced when we bear in mind, that in other mam- mals — the Carnivora more especially — this * Blandin, These Inaug. sur la Structure de la Langue de Bceuf ; also, Memoire, &c., Archiv. Gen., torn. i. 1823. RUMINANTIA. 535 septal fibro-cartilaginous aponeurosis (which we take to be the homologue of the true lingual bone), is strongly indicated. Much confusion has arisen in regard to the muscles constituting the cortex of the tongue. The general term lingualis has been applied to numerous muscular bundles situ- ated on the dorsum immediately beneath the lingual fascia. According to Gerdy they may be arranged in four groups * ; of these the most superficial layer appears to be quite distinct from the rest, and on this account it has been separately described as an indepen- dent muscle by Bauer and Zaglas, the latter aptly designating it the noto-glossus. This superficial muscular mass spreads over the whole upper surface of the tongue ; it ap- parently exists in all mammifera, being more highly developed in some than in others ; it is feebly indicated in the Camel. Without accepting the following inference, we may remark that Dr. Mercer, in his " Anatomical Observations on the analogous Structure of the Lingualis and Panniculus Carnosus," en- deavours to show that one of the principal offices of the lingualis is to erect the rasp- like papillae ; and it is evident that he only attributed this function to that portion of the muscle, since denominated the noto-glossus, for, he adds, "the first " layer of the lingualis, " which is the most conspicuous, can alone act on the surface of the tongue and its pa- pillae." -f- The fibres of the lingualis, properly so called, take their origin from the lingual margins near the root, and pass transversely or obliquely inwards to a point a little be- yond the middle line ; in the short-tongued quadrupeds and in Man the bundles reach as far forward as the tip, but in the ruminants their extension is comparatively limited. Re- specting the disposition of the associated muscular filaments, collectively termed the transversus, considerable difference obtains in regard to what may be called the fibres of insertion. In the ruminant type, where no lingual septum is present, the fibres decussate with those of the opposite side, extending therefore beyond the mesial plane, while on the other hand, in Man and animals having a well-marked linea albescens — such as is seen in Carnivora — the fibres do not pass beyond the middle line, but are intimately united to the septum (Zaglas). The perpendicularis extcrnus offers nothing remarkable, and the glosso-palatinus and glosso-pharyngeus have no existence in this order. The distribution of the vessels and nerves of the tongue have the same general arrangement as in other Mammalia; but in consequence of the greater longitudinal development of the organ they exhibit a corresponding aug- mentation. Prof. Owen remarks a disparity of calibre affecting the lingual arteries of the Giraffe, that of the left side being paramount and anastamosing freely with the vessel of * Gerdy, Anat. et Physiolog. de Langue : Ar- chives Ge'nerales de Me'decine, torn. vii. p. 363. t Anatomical Observations, &c. Edinburgh, 1841. the right side as far as the commencement of the prehensile portion — judging from the lithographed representation appended to that distinguished anatomist's " Memoir." Our own specimen exhibits this peculiarity in a still more striking degree, the left vessel being — as compared with the right — a mere arterial twig. We have not found this vas- cular anomaly in the Cervidae proper, neither is it present in other allied genera. The lingual veins in Camel opardalis are particularly broad and somewhat plexiform, and the nerves, in the retracted condition of the tongue, are beautifully tortuous. The salivary glands are chiefly noticeable on account of their large dimensions and elongated excretory passages. The orifices of the Whartonian ducts, are visible at the anterior part of the mouth beneath the tongue, and in the Giraffe are protected by two small membranous valvular folds fringed with pa- pillae. The tonsils are bulky, and in the Camel communicate with the oral cavity by numerous canals, the apertures of which are surrounded by slight prominences of the mucous membrane. In Camelopardalis, the amygdala assume a higher type of structure, and open by a short common duct capable of admitting the tip of the little finger. There is yet another peculiarity in the faucial region of this aberrant cervine genus, arising out of the presence of a rudimentary uvula, which on close inspection we find to be made up of three minute papillae, intimately conjoined at their bases. The oesophagus, in accordance with its functional activity in this family, is thick and fleshy. It is surrounded by two distinct layers of muscular tissue — an outer and inner : the fibres of the former being trans- versely circular, those of the latter ob- liquely longitudinal. They have a deeper colour than obtains in the non-voluntary muscles, but do not exhibit any transverse striae ; in some particulars, however, micro- scopic investigation has shown them to resemble very closely the voluntary type (Owen).* The ruminant stomach affords a striking illustration of the special evolution of a com- plex mechanism from the general or more simple type of structure, and to the mind of the unprejudiced truth-seeker it irresistibly indicates evidence of design ; this train of reasoning is not weakened by the fact that two, if not three, of its divisions are essen- tially dilatations of the lower extremity of the oesophagus. The first compartment or Paunch (b,Jig. 359.) — otherwise called the Rumen, Inglu- vies, or Pause — occupies a considerable proportion of the abdominal cavity. It is the largest of the four stomachs, and its gene- ral form is that of a square with rounded angles. Externally there are two well- * The sharks, which possess the power of eject- ing their stomachal contents, have the muscular fibres of this viscus marked by transverse striae. We have seen this in Lamna cornitbica. M M 4 536 RUMINANTIA. marked constrictions, corresponding to folds an enormously distended coil of intestine bent of the lining raucous membrane ; and thus into the figure of an italic S. In the typical subdivided, the viscus resembles, as it were, species the internal surface is densely beset Fig. 359. Composite stomach of the Sheep. with villi ; these give to the membrane a pe- culiarly rough aspect, and at different portions of the cavity their form is curiously modified. Usually they are remarkably prominent, pe- dunculated, more or less club-shaped and compressed; or they may be tapering and pyriform. In some localities their size is insignificant, and they almost disappear at the margins of the salient folds. In the Gi- raffe we find their dimensions strikingly uni- form at one spot, while, in another region great irregularity in this respect is observable ; the same remark holds good in other horned species, where the deviations from this type are too slight to merit a separate notice. The organisation of the paunch in the Camelidae differs very materially from that of the ordinary ruminant. Instead of presenting a rough internal surface, crowded with villosities, the mucous membrane is conspicuously smooth and entirely destitute of villi ; but the most remarkable feature consists in the presence of numerous small pouches, specially fitted for the reception and retention of water (fig. 360.). These Fig. 360. Water-cells in the paunch of the Camel. sacs, which may be looked upon as so many diverticula developed from the walls of the cavity, are arranged in two distinct groups — one on the right side and the other on the left ; the former being by far the larger, and in the adult Dromedary measuring about one foot and a half in length, and six inches in breadth (Meckel). The cells of each batch are disposed in parallel rows, separated from one another by strong muscular bundles, given off from a single large band of fibres which commences at the cardiac extremity of the rumen, and proceeds in a longitudinal direc- tion, dividing the entire cavity into two com- partments. The muscular fasiculi are arranged transversely, and give off secondary bundles at tolerably regular intervals, so that the rounded orifices of each sacculus are guarded by powerful square-shaped muscular sphinc- ters. Some of the cells are more complicated than others, being subdivided into numerous loculi by folds of the lining membrane. The largest of the reservoirs in the adult Drome- dary, when dilated, have a depth and width of about three inches. In the Llamas the structure of this apparatus, though more feebly indicated, is very similar to that of the Camels, properly so called. The second stomachal viscus (c,f,g. 359), — otherwise called the rcticulum bonnet, or water-bag — has a globular outline, — is of much smaller dimensions than the paunch, and forms a sort of cul-de-sac between it and the third cavity. It originates in com- mon with the rumen, and like that organ may be regarded as a kind of hernial dilata- tion of the lower end of the oesophagus. By some it has been looked upon as a mere ap- pendage to the former, being continuous with it at the upper and anterior part, and sepa- rated only by a projecting membranous fold, precisely similar to those met with in the first cavity. In the typical species it is dis- tinguished internally by the presence of a multitude of acute-angled polygonal cells, and from this circumstance has been vulgarly RUMINANTIA. 537 denominated the honey-comb-bag. The cells are particularly shallow in the Rein-deer and Giraffe, being circumscribed by very narrow laminae, scarcely elevated above the level of the mucous surface. The lining membrane is further characterised in the horned rumi- nants by a cuticular covering developing a great number of minute and sharply pointed conical papillae, which occupy every part of the cavity, but are most prominently marked along the ridges of the laminae, imparting to these folds a denticulated aspect. In the Camels and Llamas the honeycomb-cells ac- quire a form and capacity strictly analogous to the water-cells of the paunch ; but there are some slight modifications of structure, apparently conformable with the more tem- porary or immediate purposes which they subserve. The apertures of the cells of the rumen — destined to retain water for a lengthened period — are narrow and guarded by productions of the lining membrane, while those of the reticulum, constantly parting with their aqueous contents during the ordinary act of rumination, are more patent, and not covered in by special membranous folds; moreover, in the distended condition of the cells, the external surface of the paunch is marked by a corresponding number of vesi- cular bulgings, but in the reticulum the walls remain smooth and do not exhibit any very evident traces of the contained water- cells ; their internal subdivisions are likewise more numerous and complicated than in the rumen. Another distinction — already al- luded to — between the typical and akera- tophorous species, obtains in the absence of an internal cuticular epidermis in the bonnet of the Camelidae. In all ruminants at the anterior border of the second stomach is situated a short demi-canal, constituting the remains of that portion of the oesophagus not involved in the great gastric dilatations, two of which we have now described. This elongated channel — very well shown in the accompanying woodcut, fig. 359., — forms a bond of communication between the gullet and the three first digestive cavities, and it is provided with an extension of the mus- cular tunics of the oesophagus, modified to suit its twofold office, to which we shall again have occasion to refer when speaking of the ruminating function in detail. The third stomach (d,fig. 359.), commonly called the Psalterium, Manyplies, Omasus or Feuillct, intervenes between the water-bag and the fourth or true digestive cavity, com- municating with the former by a constricted orifice and with the latter by a very wide opening. It is the smallest of the stomachal viscera, subglobular in form, and smooth ex- ternally ; but the extent of its absorbing sur- face bears no relation to the diminished bulk of the organ, seeing that it is enormously in- creased by a remarkable folding of the internal lining membrane, the duplicatures of which resemble the leaves of a book, — hence the names above indicated. The laminae are longitudinally disposed, and in the empty condition of the viscus are closely applied against each other. In breadth they exhibit proportionate differences, so that we find an alternating assemblage of lamina? presenting three several degrees of development ; one, a very narrow fold, another, very broad, and a third of intermediate width, serially intercalated between the two. Altogether about forty such septa have been counted in the Sheep, and more than double that number in the Ox. The internal surface is beset throughout with small conical, pointed pa- pillae, similar to the villi of the reticulum, those placed at the free margins of the folds being paramount. In Camelidae the psal- terium is greatly elongated, attenuated at either extremity, and three or four times more bulky ^than the water-bag ; otherwise, its organisation conforms with the pecu- liarities observable in the horned species. The fourth stomach (e, fig. 359.), techni- cally termed the Reed, Abomasus, or CaiUette, constitutes the true digestive apparatus, ana- logous to the simple gastric organ of the non- ruminating vertebrata. It is about one third of the size of the paunch, and smooth ex- ternally, has an elongated pyramidal figure, and terminates by a narrow tubular portion at the pyloric extremity, the muscular tunics at this point acquiring a considerably in- creased thickness. Internally the secreting membrane is distinguished by irregularly disposed longitudinal folds, slightly elevated above the surface and intercommunicating by smaller rugae of the same nature, having an oblique or transverse direction. There are no papillary eminences like those in the re~ ticulum and manyplies, the lining membrane being soft, highly vascular, and occupied by the follicular openings of true gastric glands as in the human stomach. At the pylorus, in addition to the ordinary narrowing usually found at this part, there exists a special val- vular process, developed from the mucous membrane at the commencement of the duo- denum ; in the Giraffe this protecting fold is situated just within the stomach (Owen). In the akeratophorous Ruminantia the reed is relatively smaller than in the horned species ; in other respects it offers no ap- preciable difference. The ruminating function is characterised by the following phenomena : — The food, on being received into the mouth, undergoes a very partial mastication, and in this crude state is speedily carried down the oesophagus, where, on arriving at the lower part, the lips of the muscular channel, placed at the en- trance of the three first stomachs, separate, so as to ensure its passage into the paunch, In like manner, subsequent to the act of drinking, the margins of the oesophageal groove open, and the water is conveyed into the cells of the reticulum. In the Camels a proportion of the fluid passes into the first cavity, there to be retained by the great water-pouches, as a special provision against those contingencies which their mode of ex- istence involves. While the coarse vegetable 538 RUMINANTIA. ingesta are being macerated by the moisture secreted from the walls of the rumen (and probably also from the water taken in by the mouth, some of which may have entered the cavity), portions of the indigestible mass are transmitted into the second stomach for fur- ther maceration, and from thence into the demi-canal, to be moulded into the form of pellets, and returned to the mouth by a kind of reversed peristaltic action. The softened bolus, thus brought back into the mouth, is destined to receive a thorough and deliberate remastication, and it is somewhat singular that this part of the process (called " chew- ing the cud ") varies in different species. Professor Owen has the merit of showing that in the Cameline ruminants the bolus is triturated alternately from side to side, whereas, the action of the teeth in the horned Ruminantia, including the Giraffe, is always in one direction — it may be from right to left or left to right — occasioned by the rotatory motion of the jaw. The necessary reduction of the aliment having been accom- plished, it is again transferred to the stomach in a pulpy semifluid condition ; but this time, instead of entering the first or second cavities, it passes directly along the (now closed) cesophageal groove into the manyplies. Here, the superfluous moisture is supposed to be absorbed before it is ultimately transmitted into the fourth stomach, in which organ the true digestive act remains to be fulfilled. The first, second, and third stomachs are incompletely developed in the newly born individual, where no chewing of the cud taking place, the food passing directly into the fourth ; in the Calf a peculiar organic acid is secreted by the lining membrane of the reed, which possesses the power of converting the albumen of milk into curd and whey : this, in the prepared condition, is termed rennet. Concretions are frequently found in the paunch, and occasionally in the reticulum, composed of various substances, such as hair, vegetable tissues, or calcareous matter, having a more or less rounded figure. The balls, so common in the Calf and Cow, result from the licking of their own hides or that of others, — the hair thus collected being rolled into the characteristic shapes by a kind of felting process going on in the stomach ; after a time they become coated with a dark earthy deposit of great hardness, the surface acquiring a considerable polish. Sometimes they have the form of compressed spheres, but are more usually barrel-shaped ; their size is seldom larger than a cricket-ball. There is a specimen from the Cow in the Edinburgh University Anatomical Museum (presented by Dr. Me Nab, of Jamaica), measuring eleven inches in length and twenty- nine in circumference. The fibrous concre- tions in the Camel consist of numerous small pedunculated pellets, strung together in bo- tryoidal masses ; at least, such is the form presented by those we have seen from a Dromedary dissected by Professor Goodsir. The formation of the so-called Bezoar stones in the stomach of the Chamois takes place in Fig. 361. Intestines of the Sheep. RFMINANTIA. 539 consequence of a partiality for saline matters, which the animal gratifies by licking portions of rock containing saltpetre; in this way, silicious and other earthy particles swallowed at the same time, accumulate and adhere together in the form of calculi. The intestinal tube is remarkable for its length ; in other respects its characters are for the most part extremely simple. Taking the Sheep as a type, we observe the descend- ing or duodenal* portion (a, fig, 361.) to be short and straight, but rather thicker than the remainder of the small intestine, which is twisted into a multitude of gyrations until within a short distance of its termination, where the convolutions cease, and the gut ascends in a direct line to join the colon (6, fig. 361.). The large intestine is scarcely broader than the small throughout the greater part of its extent; nevertheless, it is very much expanded at its commencement, and also a little dilated at the rectum ( when first formed, is that of a pellucid, and often yellowish vesicle, having an elliptic form, and at first so minute as not to exceed -§^ — TOT/" in diameter ; as, for example, in the ox, the ovary of which animal, according to Barry, would contain in a cubic inch 200,000,000 of such ovisacs. The ovisac is more or less pellucid, ac- cording to its size. In the smaller ones, the walls are so transparent as to admit of the form of their granular contents being seen through them (Jig- 377. B, c) ; but as develop- ment advances, they become merely translu- cent. The walls, which are relatively very thick in the small ovisacs, are elastic and dis- tensible, and have an undulating surface, pre- senting numerous depressions, to which is referable the plaited or folded appearance which the contour of the ovisac assumes un- der pressure. The ovisac is sometimes formed in the pa- rietes of an already developed Graafian fol- licle ; but whether originating here, or, as is more commonly the case, in the proper sub- stance of the ovary, it is always at first seen lying perfectly loose in a little cavity, exca- vated, as it were, in the substance of the sur- rounding tissues. Subsequently a covering, or tunic, consisting of a rather dense con- nective tissue, susceptible of becoming highly vascular, and closely connected with the ova- rian stroma, is gradually formed upon the outer surface of the ovisac, with which this outer covering now becomes closely united. This is the structure termed by Barry the tunic of the ovisac (Tunica S.theca folliculi). And it is by the union of these two that, according to his observations, the Graafian vesicle is formed. At this stage of its deve- lopment there exist all the elements of the completely -developed follicle, viz., the outer vascular or fibrous coat, the inner softer layer, or proper tunic of the ovisac, and the still more internal epithelial layer of granules re- presenting the membrana granulosa, together with the elements, at least, of the ovum, and the fluid contents of the sac. These constitute the most important points regarding the development of the Graafian follicle at the time of its first formation in the Mammalia generally. They serve to facilitate greatly the study of the same parts in Man. With regard to the human follicle, the cor- responding stage is most readily observed in the infant, a few months after birth. If at that age a section be made of the ovary, it will be seen to be composed of a parenchyma, which is somewhat lax towards the centre and base, but more dense in the peripheral portion of the organ. The more lax central * Page 76. of this vol., Supplement. 555 portion consists of blood-vessels and wavy bundles of connective tissue, the latter being much more distinct in the ovary of the infant than in the adult. The more dense peripheral portion is that in which alone the ova are found. It is made np almost entirely of a mass of minute ovisacs, already containing ova (fig. 373.). These ovisacs, at present in a rndnnental condition, are of various dimensions. In the example given, their average diameter was -5t*> — rcsW' But ifc happens, occasionally, that ovaries of a very early age are found to contain ovisacs or Graafian folHcles of com- paratively Targe size. Thus, in a specimen in my possession from a child of seven months, one ovary contains a foliicTe of rather more than V'T in diameter, whilst the other is almost entirely occupied by five follicles, the largest of which measures 2£+ l|///r, and the smallest is one quarter of that size. In this case the entire length of the ovary is only 7/7/. Second Stage. Growth, Maturation, and Pre- paration for Dehiscence of the Follicle. — When the period approaches, or has already arrived, at which an animal becomes apt for reproduc- tion, and is ready to receive the male, a cer- tain number of folRcles progressively increase in size, and become more and more superficially placed. Shortly, the more advanced series occupy the surface of the ovary, and present the appearance of round grains close-set, so as to give to the organ sometimes the appearance of a bunch of grapes {fig. 378.). This is more particularly the case in the sow, which affords an excellent example for tracing these changes in the follicle. Fig. 378. Portion of ovary of the sow. The Graafian follicles project above the surface of the ovary. Several, riper than the rest, are conspicuous by their size, a, unripe } b, riper follicles ; c, strotna. (After Pouchet.) Each grain, a, consists of a vesicle filled with a limpid fluid, albuminous, viscid to the touch, of a slightly yellow colour, and coagulable by heat and alcohol. Their walls, previously diaphanous, now become opaque from the thickening of the inner membrane of the vesicle, i. e.t of the ovisac itself. From four to six of these vesicles will be found to become simultaneously developed in each ovary (fig. 378. M)- These are always the most superficial. Their form is generally ovoid. They increase until they attain a diameter of about ". 556 UTERUS AND ITS APPENDAGES. The augmentation in bulk of the follicle is, in the first instance, due almost entirely to an increase in its fluid contents. It is probable that this fluid is supplied by the minute ca- pillaries with which the ovisac is furnished, and which, long before the vesicle has attained its full diameter, appear in the form of a rich network upon its inner surface, giving to the latter a bright red colour. And now a thickening of the walls of the follicle becomes very manifest, accompanied by an exudation of blood which collects in the interior of the sac. The period at which this escape of blood commences is variable. Some- times it may be seen in follicles of not more than \\'" diameter, but more frequently when they have attained a size of about 3'". As this exudation of blood takes place at a period certainly antecedent to the rupture of the follicle, it cannot be traced to vessels lacerated during that process, but must pro- ceed from the congested capillaries just de- scribed. It resembles arterial blood, and is rich in globules, which at first remain free and distinct ; but when the distension of the fol- licle has become considerable, the blood co- agulates into a dark-red clot. This pouring-out of blood has been termed the menstruation of the follicle ; but beyond the purpose of increasing the distension of the latter, preparatory to its rupture, no use has been assigned to it, except by Pouchet, who maintains that in the sow the ovum lies at the bottom of the follicle, instead of near its upper or free surface ; and that as the sanguineous exudation increases, it collects between the inner surface of the ovisac and the membrana granulosa, and so carries up- wards the latter, together with the ovum which is lodged upon it. He asserts, further, that in proportion as this exudation increases, the albuminous fluid previously occupying the follicle is absorbed, until the entire cavity be- comes filled with blood. The result of this process is, that the ovuin, previously lying at the bottom, is now trans- ported to the upper part of the follicle, imme- diately beneath the point at which the rupture of the walls is about to take place. Notwithstanding the minuteness of Pou- chet's description, its accuracy, so far at least as concerns the supposed purpose of this exu- dation of blood, has been called in question. The fact, however, cannot be disputed, that, in many animals, as well as in man, the follicle does contain blood, often in considerable quantity, previous to its rupture. And this is a very important point, because it serves to refute the statement of some who maintain that the presence of blood, or of a clot, within the follicle, affords certain evidence that the rupture of the latter, together probably with the escape of the ovum, has already occurred. Barry also, in his researches upon the rabbit, says, that after certain of the ovisacs have discharged their ova, "some of the larger Graafian vesicles, remaining unbroken, are fre- quently found to contain a considerable quan- tity of blood. Such spots, he observes, have been noticed by several observers, who sup- posed them to indicate the Graafian vesicles from which ova were destined to be expelled. Thus Barry's prior testimony serves to confirm that of Pouchet and others, to the effect that the blood found within the follicle does not result from its rupture, but that it is there antecedent to that process. Some other changes which occur, in the follicle previous to its rupture may here be noticed. The thickening just spoken of takes place in the inner membrane, or that which constituted originally the ovisac. This thick- ening is sometimes so considerable as to in- crease the diameter of the follicular walls to three times their original amount. At the same time, their contour becomes somewhat undulating, and their colour approximates to that of the buffy coat of the blood. While these changes are going on in the substances and in the contents of the follicle, preparation is being made externally for the rupture at a certain part of the parietes. The base of the follicle continues to be imbedded in the substance of the ovary {fig. 379.), but the upper portion projects free above this, being covered only by the usual ovarian in- vestments. Here, at the more salient portion of the projecting vesicle (fig. 379.), an in- creased vascularity is observable. The peri- toneum and sublying tissues become exceed- ingly red, and an abundance of blood is observed in the numerous capillaries which are now visible upon the summit of the vesicle. After this, the fibres of the ovarian coverings become gradually separated, preparatory to their com- plete laceration. The tunics also of the fol- licle itself become perceptibly thinner at this spot, which corresponds with the situation of the ovum — always, at this period, lying im- mediately beneath it. Fig. 379. Portion of ovary of the sow. The follicles are in a more advanced stage than in fig, 378. Two of these are preparing for rupture. Already a small aper- ture is perceptible in the centre, immediately above the spot where the ovum lies; and towards this point the bloodvessels converge. {After Pouchet.} The same regular sequence of changes, which may always be traced in the Mammalia, though with some slight variations according to species, occurs also in man. If the exami- nation be made in a young and previously healthy woman, who has menstruated regularly up to the time of her death, there will gene- OVARY— (FUNCTIONS). rally be found in the ovary one or more fol- licles in conditions similar to those just de- scribed. The ordinary state in which the Graafian follicle is found has been explained at p. 550. Vesicles in the state there de- scribed may be seen at all times in the healthy ovary, sometimes near its surface; and at others buried more deeply; but when they increase in growth beyond this size, and are preparing to rupture, one or more will always be found approaching the periphery of the ovary, or rising above the level of its outer tunics, constituting there a nipple-like pro- minence, so distinct as at once to arrest attention, and to point out the part of the ovarv in which the dehiscence will next occur Fig. 380: Ovary from a woman aged 22, who died on the tenth day after the commencement of her last menstrual period. (Ad ' A follicle is preparing for spontaneous rupture at a, where a considerable prominence occurs, and where the peritoneal and albugineous coats are almost entirely absorbed. In general, only one follicle will be found preparing for rupture ; but sometimes two, or possibly three, may be observed in the same condition in one ovary. The growth has now been so considerable, that instead of measuring only li"' — 2£"', or even 3'", it has now a di- ameter of 51 — 7'", the breadth being usually somewhat less than the length, for it rarely happens that the follicle is perfectly spherical. In consequence of this increased growth the follicle projects from the surface, and causes the swelling just described, whilst the accu* mulation of fluid within it produces a softness and sense of fluctuation in this part of the ovary, which is very obvious to the touch. Over the centre of this projection the pe- ritoneum is exceedingly thin, and in some places is wanting, partly from absorption, and partly from laceration, the result of over- stretching and distension. The tunica albuginea also of the ovary may be absorbed, or may have become so exceedingly thin, as to permit the blood- coloured contents of the vesicle partially to appear through it, giving to the spot a 557 peculiar brick-red colour. Around the mar- gin or base of the prominence the fibres of the tunica albuginea are often seen to be separated at short distances, forming concentric lines or interrupted circles ; the red contents showing through the interspaces, and producing an appearance of alternate white and red lines (fig. 380. £). Beyond this circumference, the base of the promi- nence exhibits the usual white colour of the ovarian coverings. Numerous red vessels, chiefly veins (fig. 380. c), ramify towards the projecting spot, and some of these traverse it to its summit, coursing over the promi- nence in serpentine lines, and forming here a rich plexus. A clean section through the centre of the projecting follicle lays open an ovoid cavity, Fig. 381. The same ovary (ad Nat.') as in fig. 380. laid open, displaying, a, the cavity of the enlarged follicle ; c, the corre- sponding half of the same ; b, a blood-clot. Nu- merous follicles of the ordinary size are seen scat- tered through the ovary. (fig. 381. a), containing usually a deep red clot, b, together with a certain quantity of blood and a bloody fluid. The clot has as yet no adhesion to the walls of the cavity, and is easily washed away. If the ovary has been examined not too long after death, the ovum may possibly be found lying imbedded in the granules of the mem- brana gramdosa, immediately beneath the most projecting point of the follicle. But more commonly, the examination not being made until after this delicate membrane has melted down, and its granules have become dispersed by post-mortem change, the ovum cannot be discovered. After washing out the contents of the follicle, the inner surface of the ovisac is ex- posed (fig. 381. c). This I have occasionally seen to be of an intense red colour, from the surface being covered by a rich network of ca- pillaries filled with blood. But most com- monly the colour of the ovisac throughout, as far as the outer tissue of the follicle, is at this time a clear, pale, chrome yellow, this coat being now also very soft in texture. It is important to observe that the yellow colour includes the whole thickness of the ovisac, or inner coat of the Graafian follicle, which now mea- sures from £ to 1"' in thickness, but that it extends no further ; the outer coat, or theca 558 UTERUS AND ITS APPENDAGES. folliculi, retaining its ordinary condition. Already a slightly wavy outline is perceptible in the follicle (fig. 381.), which is due to the growth of the inner membrane having con- tinued after the outer coat has ceased to ex- pand. The inner coat of the follicle, when it has thus acquired a yellow colour, is seen, by the aid of the microscope, to have undergone an important and yet very simple change. On its inner surface, or that which is turned towards the cavity of the ovisac, it presents the appearance of a transparent and nearly structureless membrane, in the substance of which are imbedded numerous oil droplets, very minute, and aggregated in little masses, Fig. 382. Cells filled with oil-granules which give the yellow colour to the inner coat of the Graafian follicle be- fore it has burst, forming the substance termed cor- pus luteum. (Ad Nat. x 350.) a, separate cells ; b, the same imbedded in the structureless membrane. (From the same subject as figs. 380. and 381.) with a certain regularity which suggests the idea that they have either been originally deposited around a centre globule, or are contained in cells or vesicles, the cell- wall of which is not very discernible (fig. 382. i)^ Deeper towards the outer surface of the ovisac the oil droplets or granules become so numerous as to prevent the recognition of any other structure until the greater portion of the oil has been dissolved out by macerating the part in ether. If, after this process, the tissue which remains be washed in spirit or water, and subsequently treated by acetic acid, it is seen to be composed of numerous blood- vessels, and of developed as well as embryonic fibres of connective tissue, which latter, how- I /* • ,. 1 • •* granules" so frequently described and figured by Barry in his account of the various con- ditions and stages of development of the ovisac. The colour of the yellow coat — the so-called corpus luteum — is not alike in all animals. In some of the Mammalia it is of a bright orange ; in others it inclines to red. In Man, as already stated, the inner surface of the follicle, when ripe, is occasionally so loaded with bright red capillaries that the usual appearance is obscured, but its ordinary as- pect presents the clear chrome yellow just described. That this yellow colour, like that of the yolk of the bird's egg, is due to the presence of the oil globules (fig. 382. b) which everywhere penetrate the tissues of this coat, is rendered sufficiently apparent : first, by the fact that treatment by ether, which dissolves out the oil granules, leaves the remaining membrane nearly white ; and secondly, that maceration in water has, to a certain ex- tent, the like effect, but in this case arising from the maceration, causing the animal membrane to swell and become opaque, thus obscuring its previous transparency, and ren- dering the oily portions only faintly dis- cernible through it, as judged by the naked eye, though they are still readily discoverable under the microscope. Third Stage. Period of Rupture or Dehis- cence of the Follicle, and Escape of the Ovum. —This is termed by Pouchet the period of parturition, in which, after the preparatory changes already described, the ovum quits the Graafian follicle in order to enter the Fallopian tube. It is therefore for the ovisac what the process of parturition is for the uterus, viz., the act by which the ovum, after being matured to a certain point of perfection, is expelled from its cavity. The process by which the dehiscence of the follicle is effected in Mammalia is in some re- spects different from that which causes the expulsion of the ovum, from its containing capsule, in the vertebrata below them. In ever, are only faintly indicated, and are con- birdX reptiles, and fishes, and, indeed, in nected together by a transparent membrane. tne Invertebrata generally, the ovum is of so The proportion of developed fibres of con- nective tissue is here very large, whilst in less advanced follicles the embryonic fibres preponderate (fig. 375.). Another and perhaps more satisfactory mode of examining the yellow coat of the Graafian follicle in this stage, consists in slow maceration in a very weak preservative fluid (glycerine and water). The cells, which this coat contains in great abundance, can now be obtained separately for observation. They are seen to consist of a transparent cell-wall, filled with oil granules (fig. 382. a). The average cells vary in diameter from ¥£T// to aoV(/'> but many are smaller, and others lar- ger. Occasionally a cell may be seen to have burst, its contents having escaped ; a few oil granules, however, may still be perceived ad- hering to the cell-wall, the torn margins of which are very readily defined. There can be no doubt that these cells are the "peculiar large a size in comparison with the ovicap- sule, that the simple increase of the former, as the time of theovipont* approaches, is suffi- cient to cause the bursting of the sac at the point where the coats have been prepared for rupture by previous attenuation. But in the Mammalia the bulk of the ovum bears so small a proportion to its containing follicle, that the ovum itself contributes in no degree to the rupture by which it is enabled to escape. In this process it remains a passive body, at least in a mechanical point of view, though doubtless it is the perfecting of the ovum which gives the vital impetus to that series of changes by which it is finally released from its first abode. But the act of * I have anglicised the French term oviponte (ovi- pont), to express the escape of the ovum from the ovary ; while " ovulation " is employed, in a more general sense, to include also the process of its maturation. OVARY — (FUNCTIONS). parturition is accomplished by other means. The process by which this is effected has been compared by Blumenbach to the spon- taneous bursting of an abscess. Here the process consists in an increasing accumulation of fluid within, conjoined with a gradual attenuation of some particular part of the containing walls. So many points of simi- larity, indeed, may be traced between these two processes, that the term " inflammation " is employed by some authors in describing the preparatory changes in the Graafian fol- licle. The resistance which the ovum and other contents of the vesicle require to overcome before any portion of these can escape con- sists, it must be remembered, in the combined opposition of no less than four membranes, in addition to any portion of the proper ovarian stroma which may intervene. These are, first, the ovisac ; then its capsule, united to the former, and with it constituting the Graafian follicle; thirdly, the tunica albuginea ; and fourthly, the peritoneal covering of the ovary. These four, shortly previous to the rupture, become so intimately united together that it is no longer possible to separate, nor is it easy always to distinguish them from each other, with the exception, however, of the innermost layer, which can generally be more easily traced than any of the rest, on account of its peculiar yellow colour. Upon the surface of the most salient por- tion of the projecting follicle (jig. 380. a) the peritoneum, as already stated, may be wanting; the tunica albuginea also beneath has become greatly attenuated, and is sometimes found completely eroded, whilst internally the yellow coat of the follicle is also observed to be thinnest about this spot. Every preparation, therefore, is made for the laceration of the follicle at a given point, the seat of which can also be further determined by the observation that in this place the conjoined membranes, previously highly vascular, have become more transparent, "whilst their vessels, having be- come atrophied by compression, now carry little or no blood. A very slight force is now sufficient to produce the rupture of the follicle in this precise spot, and such a force is supplied by the gradual accumulation of fluid, whether albuminous or sanguineous, or both, within the cavity. It is believed by Coste that when the ovi- sacs have reached this point, which is the full term of their growth, they may remain stationary until a state of excitement arises, produced partly by the maturity of the ovum, and partly by the approach of the sexes, and that it is under the influence of such an ex- citement that the rupture of the follicle most commonly takes place. What probability there is for such a supposition will be here- after more fully considered. Whether in- fluenced by any external stimulus, or whether occurring spontaneously, and from causes existing within the follicle, the increase of its fluid contents becomes at length so great that 559 the cavity is distended beyond measure, and its walls can no longer resist the pressure, but give way at the thinnest and most pro- jecting part. But it is probable that another power comes also into operation to aid this process. The wavy outline which has been already noticed (fig. 381. c) as presented in a slight degree by the still unbroken ovisac, to- gether with a certain amount of thickening of this coat, indicates a growth of this more rapid in proportion than that of the outer layer or tunic of the ovisac. This, therefore, will in some degree add to the pressure, be- cause the outer layer of the follicle not being distensible beyond a certain limit, any in- crease of the contents, whether fluid or solid, will alike contribute to augment the force which is brought to bear upon the weakest point of the walls. As soon as the rupture has taken place, and the opening in the coats of the follicle and in the corresponding portion of the ova- rian coverings is sufficiently large to admit of the passage of the ovum, the latter escapes, together with portions of the membrana gra- nulosa. On one occasion Pouchet was so fortunate as to meet with an opportunity of observing the ovum as it was in the act of escaping from the ovisac, and was lying between the margins of the lacerated opening. Of the five coats which together compose the ovarian and follicular walls, four only, it will be observed, can offer any obstacle to the escape of the ovum; because the membrana granulosa, which is the innermost of all, con- tains rather than covers the ovum, whose escape cannot be impeded, but will be rather assisted by that membrane. Barry explains the mode in which this probably occurs as follows: — The ovum, imbedded in the cu; mulus and granular disc which form the centre of the membrana granulosa, at the moment when the laceration occurs, experiences the vis a tergo occasioned by the pressure forward of the fluid, endeavouring to escape from within the follicle. This pressure is increased by the thickening of the inner wall of the follicle, amounting in some instances to an exuberant growth, which will act upon the ovum through the medium of this fluid. The obstacle to the escape of the ovum w hich had up to this moment existed, being removed by the laceration and absorption of the ovarian and follicular walls, that portion of the mem- brana granulosa which lies immediately behind the lacerated coats, where the ovum is im- bedded, presents a surface for the operation of the vis a tergo more or less considerable, according to the extent of the rupture. And now the elasticity of the coats of the follicle, together with some pressure from the weight of the parts surrounding its base, come in aid of this force, and complete the expulsion of the ovum, which escapes together with a portion of the membrana granulosa, and passes into the infundibular end of the oviduct. Fig. 383. shows the mode in which this pro- 560 UTERUS AND ITS APPENDAGES. cess occurs in the rabbit. Here is represented a portion of a ripe Graafian vesicle, which was upon the point of discharging an ovum. The follicle, after being dissected out of the ovary, has been subjected to slight lateral pressure in the compressorium, by which the follicle has been burst at the point (//) preparing for rup- ture. The ovisac has given way at the thin- nest point, and the ovum, surrounded by the tunica granulosa (g, 1.), and dragging after it portions of the retinacula (g, 2.) is shown in the act of escaping from the follicle. Fig. 383. Ovum of the rabbit in the act of escaping from a rup- tured Graafian follicle. (After Barry.) The ovum is surrounded by the tunica granulosa, g\ and draws after it the portion of membrana granulosa termed the retinacula, #2 . at h, where the rupture has taken place, the coats of the follicle are attenuated, and towards this spot numerous vessels converge. The form and size of the aperture by which the ovum escapes varies considerably. In the rabbit it generally appears in the form of a small round aperture in the midst of a bright red spot, which is margined by a little net- work of capillaries filled with blood (Jig. 383. h). In the sow the aperture is generally oblong Fig. 384-. Portion of ovary of the sow. Three of the largest follicles have burst simultaneously, and exhibit wide lacerations. Others, less forward, remain unrup- tured. At the base are several unripe follicles. (After Pouchet.) (Jig. 384.), and from li to 7"' in length; the laceration in the latter sometimes extending through the entire diameter of the follicle, and permitting the .escape of the whole of its con- tents, together with the ovum. The laceration is not necessarily limited to a single follicle. In multiparient animals (Jig. 384.) all or a greater portion of those follicles which have attained their full de- velopment undergo laceration, and emit their ova about the same time. In some of these, however, the effort may prove abortive, and the follicles may remain stationary until an- other impulse to rupture occurs, and the ova may then be discharged, or may, on the other hand, perish or be absorbed. In Man, although generally uniparient, two or more follicles may likewise become ma- tured about the same time, and their bursting may take place simultaneously. Of this fact 1 possess the proof in a case (fig. 409. page 605.) in which I found in one ovary three distinct apertures leading to as many developed ovisacs, all of which presented the characters just de- scribed as indicating the recently ruptured follicle. In this case the woman died during menstruation. Such an observation is interesting, as show- ing in what way multiple pregnancies may occur in the human subject, for the whole of the ova discharged under such circum- stances may be impregnated by a single coitus ; although it is also possible that the bursting of one follicle only may suffice for the pro- duction of twins, since two ova have been several times observed in a single follicle in the Mammalia, and this may also possibly be sometimes the case in Man. Before proceeding to the consideration of the remaining changes which the Graafian follicle undergoes, it may be useful here to make one or two observations on the con- ditions already described. Up to the moment of rupture, the progress of the follicle is one of regular advancement from an embryonic condition to a state of full maturity. The object of this progressive advancement is the protection, maturation, and final expulsion of the ovum, in such a manner that this last step may occur at a time when the ovum will be placed in circumstances the most favourable for impregnation. In order to accomplish this, the ultimate purpose of all these progressive changes, the ovisacs which had been previously set more or less deeply in the ovarian parenchyma reach, one by one, the surface of this organ, and there, swelling rapidly from the increased secretion into their interior, and the growth of their walls, as we have seen, burst and emit their contents. The whole of these changes occur in regular sequence, and affect one or more follicles in succession. These follicles, lying buried in countless numbers in the substance of the ovary, supply, as it were, the pabulum for the morphological changes here described ; a certain number only being called into full maturity, whilst the greater portion of those which were originally formed OVARY — (FUNCTIONS). in infancy, or which may continue to form during life, undoubtedly perish. No sexual influence is needful to the production of any of these changes. The whole occur sponta- neously, whatever may be the condition of the female. How far the influence of the male may assist in hurrying on to maturity any of the.se pro- cesses is a question which will be considered hereafter, when the proofs of the statements now made as to the independence of these processes will also be investigated. But it is sufficient here to refer to the fact of the spon- taneitv of these occurrences, in order to place under one category all the changes which the ovary suffers, up to a certain point, independ- ently of any sexual influence. Two circumstances here also may be more especially noticed : the one is, that the yel- low colour which the proper ovisac or inner coat of the follicle exhibits towards the term of its ripening is distinctly recognisable for some time anterior to the occurrence of the rupture. It occurs in all follicles at this stage alike, both in Man and animals, and under all circumstances, whether coitus be permitted or not ; but even when coitus is permitted, it is found at a period long anterior to that at which the act of coition could by any possibility be influential in its production. The other circumstance which it may be important here to notice is, that the yellow structure is no new nor superadded part, but is the ovisac itself, altered by the gradual de- posit in its texture of a yellow oil, which at length accumulates to such a degree as to con- vert this previously translucent wall of the follicle into an opaque yellow membrane or coat. But neither in any of these stages, nor in any subsequent ones, is there interposed either between the walls of the follicle or be- tween these latter and the surrounding ova- rian stroma, any new substance or body of any kind. The yellow colour is confined to the inner coat of the follicle, nor have I ever seen it in any one instance penetrating to the outer coat or covering of the ovisac. There is only one new coat formed, which will be hereafter described ; and that coat, often of considerable thickness, is a part entirely superadded, which, after a certain stage in the metamorphosis of the follicle, is applied in the inner side again of the yellow coat, to which it forms a lining. This, although a new forma- tion, is also, as will be presently shown, con- structed out of materials existing in the fol- licle before its rupture. The final purpose of the Graafian follicle being now accomplished, it may seem a matter of comparatively little interest or importance, in a physiological point of view, to trace its ultimate conditions ; for the changes which this structure next undergoes have for their object solely its obliteration. But the process of obliteration or retrogression does not, like the process of development, take place under all circumstances alike. Here the influence of impregnation is exhibited in a degree so remarkable as to have given rise to a general Supp. 561 belief that the changes experienced by the follicle, when impregnation has accompanied or followed its rupture, are essentially different in their nature and character from those which ensue when impregnation has not taken place ; whereas these differences, it will be shown, are differences chiefly of degree; and yet they are so considerable as to have called forth almost as great a share of attention as has been given, perhaps, to any structure in the human body. But great as is the interest attached to this structure on account of the evidence which it may afford of the previous occurrence or non- occurrence of impregnation, yet, so various are the views and statements of those who have specially directed their attention to the subject, that neither among physiologists, pa- thologists, nor medical jurists, can it be said that there is at present any concord of opinion or common ground of understanding. Admitting, however, for the present that there is a marked difference observable in the changes which the Graafian follicle undergoes, according as impregnation has or has not ac- companied or followed the escape of the ovum, we thereby obtain a starting-point, or rather a point of divergence, from which we may follow out these changes in two dif- ferent series : the one series will include the alterations in the follicle which ensue when impregnation fails, or does not oc- cur ; the other, those which it experiences in consequence of impregnation having taken place. Fourth Stage. Period of Decline and Obli- teration of the Graafian Follicles. A. Without Impregnation. — This constitutes the first degree of the descending scale in the history of development of the follicle. Im- mediately after the escape of the ovum, the inherent contractility of the tunica albugi- nea of the ovary occasions a diminution in the prominence of the lacerated vesicle. The margins of the opening become approxi- mated in consequence of the collapsing of the walls, and from the edges of the laceration there occurs a slight fibnnous exudation which causes them to become agglutinated. If the aper- ture has been of considerable size, and no clot remains in the cavity to keep its walls from collapsing, the process of obliteration may proceed rapidly ; but if a clot remains, and especially if it is of considerable size, it will serve to support the walls, and prevent them from quickly shrinking. These different conditions will for a time affect the new disposition which the inner membrane of the follicle takes soon alter the rupture is complete. In proportion as the cavity is empty, the elasticity of the outer fibrous coat will, by its retraction, occasion a diminution of the cavity; but the inner coat, bavins: already increased during the growth of the follicle in a greater degree than its outer covering, will now, in this collapsed and nearly empty condition of the sac, suffer the same change that would result from en- closing a large bladder within a smaller one. 0 o 562 UTERUS AND ITS APPENDAGES. The inner coat becomes folded, and forms convolutions, which increase and become deeper in proportion as the retractility of the external tunic increases. These convolutions in the inner and now yellow coat of the follicle are so distinct and striking (Jig. 385.) as to have suggested those comparisons with the cerebral convolutions which so many authors have employed in describing this change ; for the colour, as well as the nature and arrangement of the foldings, constituting ridges and sulci, produce an exact miniature resemblance to the surface of the brain. If the blood-clot, which is generally found contained within the ruptured ovisac, be of considerable size, its surface will frequently exhibit little furrows, more or less deep, cor- Fig. 385. Section of the ovary of a woman who was poisoned by opium. A large Graqfian follicle, which had re- cently burst and discharged its contents, is laid open. The part of the ovary surrounding the aperture was loaded with vessels full of blood. The convolutions of the collapsing follicle are very distinct. The follicle is empty. (Ad Nat.) responding with the convolutions of the ovisac, by contact with which they have been im- pressed. This clot becomes adherent to the walls of the ovisac; assumes by degrees a pale rose hue ; and gradually diminishing by absorption and contraction, it constitutes a centre, towards which the rays of the convolu- tions from all sides are directed. But if there be no considerable clot in the centre of the follicle, then its closure proceeds more rapidly. The angles of the convolutions approach each other more nearly, but there still remains a space in the centre which may be empty, or contains only the debris of old coagula. Lastly, if the cavity is empty, the retracti- lity of its outer coat soon effects its closure. The angles of the convolutions, now com- pressed one against the other, come into contact across the cavity, and end by adhering together, and so the cavity is obliterated. If, during the progress of these changes within the follicle, the external surface of the ovary be examined about the seat of rupture, it will be found that the parts in the imme- diate neighbourhood of the laceration become paler, that the blood gradually deserts the ves- sels, which were before highly congested, in this situation; and that, as cicatrisation ad- vances, the zone becomes less and less dis- tinct, disappearing, finally, about the time when the last traces of the laceration are effaced. These changes in the ovarian follicle after rupture exhibit certain differences among the Mammalia, in some of whom, for example, there may be seen to project from the aperture a fleshy mass, sometimes occasioned by the presence of a coagulum, but more constantly by an exuberant growth of the lining mem- brane of the follicle, which for some time protrudes through the orifice, and may often, at this stage, be drawn out entire by the for- ceps, without difficulty. Its colour is not alike in all the Mammalia. In the sow, it resembles the liver of a calf; in the cow and sheep, it is of a brick-red. In Man, the follicle has generally shrunk to very small dimensions by the time that one or more of th'e next series, which is preparing for development, have reached and protruded from the surface. The cavity by this time is nearly effaced. The chrome-yellow colour of the walls has also disappeared, and the ovisac has gradually become white. Its appearance upon section at this time is very striking and characteristic. In the centre (fig. 372. /z) is still perceptible a small space, which might contain the head of a pin. It is surrounded by a white irregular circle, from which pro- ceed outwardly about a dozen little rays. The circle is formed by the united inner angles of the follicular convolutions. The rays consist each of a double layer of the folded membrane. The apices of the rays are the original outer angles of the serpentine folds or convolutions of the ovisac. The outer coat of the Graafian follicle can now no longer be seen. At this time, the remnant of the shrunken vesicle measures about 1%'" diam. Finally, whilst the foregoing changes are proceeding internally, a corresponding altera- tion takes place at the surface of the ovary. OVARY— (FUNCTIONS). The closure of the aperture, by cohesion of its opposite sides, occasions a drawing to- gether of the surrounding parts, and the ac- companying collapse of the follicles causes the part of the ovarian surface in this situation to sink inwards. The depression thus caused is increased by the continued shrivelling of the follicle, and by its retiring inwards to- wards the centre of the ovary. This latter change is occasioned not so much by any ac- tivity on the part of the now empty follicle as by the approach of new and rising ones to the surface, by which the empty and useless ovisacs are now pressed aside. By these successive retirings of the follicles after bursting, and by the cicatrisation of their apertures, the ovarian surface becomes gra- dually indented in all directions so as to ex- hibit those pits and furrows which are always seen upon the ovary in advanced life (fig. 390.) ; and these, occurring in women under every circumstance alike, afford one of the most convincing proofs that this discharge of ova from the ovary may and does occur independ- ently of sexual congress. Finally, the stellate remains of the follicle continue to decrease, and become gradually buried in the ovarian stroma, until they are entirely obliterated, thus giving place to other vesicles which pass through the same stages of growth and decadence. B. After Impregnation. — Very different is the progress of the Graafian follicle after im- pregnation has taken place. Here, although the changes which occur have no other intel- ligible purpose than that of the final oblitera- tion of the follicles, yet the process takes place much more slowly than it does when the ovipont has not been followed by conception. In this latter case, the metamorphosis of the follicle into the small yellow stellate organ takes place usually within a month from the time of rupture, and its subsequent reduction to the little white cicatrix previous to its total disappearance is completed in about the like period. But the follicle, which has discharged an ovum that has been afterwards impregnated, is not obliterated in a shorter time usually than 13 — 14 months. During that time it appears to undergo a great and remarkable development. But a close examination shows that this is not true development, in the or- dinary sense of the word. It is not a forward movement, progressing towards any new pur- pose or end, but is only the same process of obliteration, conducted upon a larger scale, and with a greater abundance of materials than in the case of the ordinary follicles when im- pregnation has not occurred. Apparently the chief difficulty which has stood in the way of a clear comprehension of this has arisen from a want of sufficient consi- deration of those altered circumstances in which the generative organs are placed after conception ; for, from the moment that im- pregnation has occurred, all parts of the gene- rative apparatus are brought under the influ- ence of a common stimulus, and all manifest in a greater or lesser degree some progressive 563 change. This is more particularly observable in the internal organs, and especially in the uterus, which very soon receives a larger supply of blood. But the blood-vessels supplying the uterus inosculate so freely with those of the ovary, that the two organs may be practi- cally regarded as deriving their blood from one common source. Each may be injected from the vessels of the other, and though only one set be selected, both are alike filled. Hence it may be assumed that, although there is no direct continuity of texture be- tween the ovary and the uterus, yet, under the influence of a common supply of formative material, as well as a common innervation, there may be established such a consent of action as will account, in some degree at least, for the differences which we are now about to consider; for when, after the discharge of the ovum from the ovary, impregnation fails, or has not been attempted, the internal organs, previously highly vascular, subside into a passive or quiescent state until the pe- riod of the next ovipont approaches, when the uterus again exhibits the same condition of turgescence. But if impregnation has taken place, then the turgescence of the ute- rus, far from subsiding, only increases, and certain of its textures now become rapidly evolved. The reproductive act, however, does not commence in the uterus. The ovary is the seat of the first changes, and the uterus is only placed in a condition of readiness, on each occasion of the ovipont, to carry on and complete the process which has been com- menced in the former organ. The absence of impregnation, on the one hand, is the cause of the failure of the further stages of the pro- cess; the occurrence of impregnation, on the other hand, establishes these stages ; conse- quently the ovisac which is about to discharge, or one which has just discharged an ovum, and the uterus which is about to receive or which has just received that ovum, are both placed under similar conditions. Whatever influences the one in the direction of develop- ment, affects the other also, to a certain de- gree, in the same direction. Whatever, on the other hand, determines the retrogression of the one, determines, in like manner, the receding of the other. If the ovum has be- come impregnated, the follicle which was the first birthplace of that particular ovum, and the uterus which subsequently receives and protects it, continue alike to suffer change. But if the ovum perishes, the recipient organ feels no stimulus, is not excited to further preparation, subsides into its former state of quiescence, and its producing capsule likewise shrinks, and finally disappears. If the inquiry be prosecuted further in the hope of eliciting some more satisfactory explanation of this re- markable series of changes, the investigation will, in the present state of our knowledge, be found altogether to fail. The question, Cui bono ? continues unanswered, but the fact re- mains, and the law appears to be invariable. When conception has followed the discharge of an ovum from the ovarium, the follicle oo 2 ~s— X 564 UTERUS AND ITS APPENDAGES. which produced it closes in the same manner as when conception has not occurred, but it does not shrink rapidly, as in the latter case. On the contrary, the inner coat or original ovi- sac continues to increase in thickness, in conse- quence of a still larger deposit of yellow oil granules in its substance. The outer coat of the follicle or tunic of the ovisac suffers no change ; but upon the interior of the ovisac, and therefore lining the cavity, is formed a membrane, the origin and nature of which will be presently considered ; or else it may happen that the cavity becomes obliterated by the organisation of the clot by which it had been at first filled. After conception it is probable that the ac- tual diameter of the follicle does not at any time materially increase. So great, however, are the variations in its size in different sub- jects, that this point scarcely admits of being accurately determined. The Graafian follicle may, at the time of rupture, occupy %, £, or i- of the entire ovary. These at least are the dimensions which it is usually found to have, in different instances, during the first four months of pregnancy ; but after this period the process of diminution begins to be percep- tible. All the changes which are now observ- able in regard to form, solidify, and other par- ticulars obvious to the unaided senses, and all the histological changes are to be looked for within the outer coat of the follicle. The latter appears to suffer no alteration, but simply to follow the movements of its contained parts, around which it remains loosely applied. The ovisac, however, or inner coat, rapidly in- creases in thickness, in consequence of a more considerable accumulation in its texture of the same yellow oil whose deposition had be- gun in it long before the follicle had ruptured, and when it was only approaching the surface of the ovary. This thickening of the inner follicular coat is followed by a twofold result. The mem- brane, being confined by its outer tunic, now no longer distensible, as well as by the surround- ing stroma into which the vesicle has now begun to sink, becomes more deeply plicated ; and since it can no longer extend outwardly, it must of necessity encroach upon the cavity within. The latter thus becomes sensibly diminished, whilst the entire thickness of its boundary wall is in like proportion increased. At the end of the first two months of ges- tation, the follicle possesses considerable soli- dity. The wavy and plicated condition of the yellow ovisac is now less distinct. The whole of this coat exhibits the appearance of a thick yellow layer, still occasionally traversed by numerous little blood-vessels, which run across it in straight lines from without inwards as far as its inner surface. The larger of these vessels probably do not actually pierce the yellow coat, but lie between the sulci, repre- senting the original folds of the ovisac, and which, now pressed back to back without being yet obliterated, would still serve for the conveyance of blood-vessels to different parts of the tunic. These changes continued to be in a certain sense progressive until the fourth month of gestation, about which time the Graafian fol- licle is usually considered to attain its highest state of development. But if the term de- velopment be admitted, it should be remem- bered that the only apparent purpose of these and other changes which ensue is still the ob- literation of the structures in which they occur. The process of obliteration, however, has at this time not proceeded so far as to have caused the removal or even diminution of any of the original parts composing the follicle, whilst some new structures are super- added or produced by metamorphosis of the original materials. The follicle at this period generally affords the best opportunity for observing the changes which result from impregnation. It may therefore be selected for a critical examination of the subject. The external condition of the ovary in which such a follicle is contained serves at once to point out the precise seat which the structure occupies. Not only is the entire ovary larger than that of the opposite side, but it appears more swollen, and is perceptibly harder in one particular spot ; over or near this spot a cicatrix may still be visible, and in its immediate neighbourhood are often found some serpentine vessels. If, now, a section be made of the ovary in this situation so as not to pass through the centre, but to include only a portion of the circumference of the follicle, the latter will present the condi- tion represented in/g. 386. The follicle, in the Fig. 386. Section of the ovary of a woman who died at the end of the fourth month of utero-gestation. The Graa- fian follicle of the ovum which had been impreg- nated pmjects above the stroma. {Ad Nat.) a, outer vascular coat (tunic of the ovisac) ; b, yellow inner coat (ovisac), from which a thin slice has been removed, not deep enough to lay open the cavity, hut displaying the brain-like convolutions ; e, portion of the follicle corresponding to b. form of a little globe, is seen to occupy about a fourth part of the ovary. Its solidity and spherical form cause it to project considerably above the surface of the section. In this way is exposed the outer coat by which the follicle is bounded. Upon this coat numerous blood- vessels, derived from the ovarian stroma, ra- mify. It is the tunic of the ovisac, the origi- OVARY — (FUNCTIONS). nal outer coat of the Graafian follicle, which in all the transformations of the latter suffers no change, until the time arrives when the whole body finally shrinks and disappears. The position and relations of this coat to surrounding parts leave no room for doubt as to its identity. Nothing bounds it externally but the stroma of the ovary. Nothing lines it internally but the yellow ovisac. Neither between its outer nor its inner surfaces, and like •corresponding structures just named, is there at any time found any substance or me- dium interposed. This coat has undergone no material thickening, and its histologieal elements are simply those of the outer coat of the follicle, the same as before impregna- tion has occurred. Proceeding inwards, the next coat is yel- low ; it has a nearly uniform thickness of \$f". In its substance may still be seen traces of the original foldings or convolutions. These are more easily shown upon the sur- face of the first section (fig. 386.), but are less obvious in one carried deeper so as to include the centre of the follicle, where the Fig. 387. Deeper section of the same Graafian fottick as in fig. 386. The cavity, which contains a remarkably clear fluid, is exposed. (Ad Nat.) a, outer vascular coat (tunic of the ovisac) ; b, inner yellow coat, or corpus luteum (ovisac) ; c, white membrane lining the cavity (a new forma- tion) ; d, cavity empty. coat shows greater solidity (fig. 387.). Up to this time, however, and sometimes later, the vessels still traversing this coat in the lines of its former convolutions may be traced in many specimens, and the capillaries may still be filled by a successful injection to such an extent as to render the whole mass crimson.* Exa- mined by the microscope, the following results are obtained: — The yellow coat, \-\\"r thick, is soft, swells in water, and is easily torn into fragments which nevertheless hang together, being connected by a tough flexible medium. During this process numerous oil droplets escape, and form, with the drop of water in which the preparation is placed, a highly re- fractive fluid. This fluid, when examined, is seen to contain numerous particles of inap- preciable size endowed with molecular motion, minute granules, and oil globules, which are at first also very minute, but soon collect and * Montgomery, Signs of Pregnancy, p. 227. 565 coalesce into larger drops that float to the surface of the fluid. The substance of the preparation also is everywhere pervaded by the oil drops which obscure its structure, and prevent further examination in this state. The preparation, having been treated next by ether, and subsequently washed in alcohol and replaced in water, it is found that the oil has entirely disappeared. The principal portion of the remaining substance has the appearance of a granular membrane, but in many places slightly wavy lines of connective tissue are perceptible. From the margins project in many places flattened bands composed of 8-10 filaments of common connective tissue, united by membrane, and having attached to them numerous granules. Separate fibres also appear at the margin of the preparation, but only from forcible detachment. Treated fur- ther by acetic acid, the oil globules, as well as the fibres, have totally disappeared. The course of the latter is now only indicated by numerous lines of round, oval, or elongated nuclei (fig. 388.), which are everywhere abun- dantly seen attached to a fine, structureless, transparent membrane. The outlines of the Fig. 388. X 350. nuclei are very sharp and distinct, and within them are contained one or two nucleoli. This coat is traversed by numerous blood-vessels and capillaries, and to their coats in all proba- bility many of these nuclei belong. The yellow coat is bounded internally by a third tunic which is white, having pre- cisely the milk-white colour, and very nearly the consistence, of articular cartilage. It is of variable thickness, but often f" or more in diameter. It is very tough and cohe- rent in texture, and is with difficulty split by needles, breaking into irregular fragments. These, examined by the microscope, are seen to be composed of tough fibres of con- nective tissue, whose arrangement in wavy lines may be perceived through the mass, but which are so closely connected together by a semitran.sparent membranous medium as to be inseparable into distinct fibrillas, except at the margins of the fragments, where they are tolerably distinct ; where also the connecting medium may be seen in the form of a struc- tureless membrane. Minute granules are every- where seen scattered throughout the mass, and adherent to the detached fibrillae. Treated by acetic acid, the fibres become transparent and pale, their outlines being hardly distin- guishable. Oval nuclei, rather scanty, lie in the direction of the fibres. The whole sub- o o 3 566 UTERUS AND ITS APPENDAGES. stance has the appearance of a tissue which is in a low state of vitality. It is probable that the presence of this coat within the follicle has been the cause of most of the differences of opinion which have ex- isted regarding both the seat and the nature of the yellow portion of the follicle of preg- nancy. It seems to have been assumed, with- out further examination by many who have written upon this subject, that the coat last described is one of the coats originally com- posing the Graafian follicle ; whereas it is formed by the metamorphosis of the blood-clot, already described as occupying the centre of the follicle before even the ovum escapes. I have seen very distinctly the fibrillation of this clot soon after the follicle has closed. It is then found to be gradually becoming pale, the red particles disappear by degrees, the clot adheres firmly to the inner surface of the ovisac, and the mass is converted into the low form of tissue just described, which ma)' either take the condition of a membrane lining the cavity and leaving a central space filled by transparent fluid, or the whole may be con- verted into a solid body. Either of these forms may be observed, and the knowledge that each may occur disposes of the specu- lative question as to the time when the cavity of the follicle is obliterated. On the other hand, the yellow coat which has been often described by authors as altogether a new formation, deposited either between or external to both of the follicular coats, can be most easily traced through all its phases, be- ginning in the ascending vesicle, as the original ovisac ; its structure filled with nucleated cells, which gradually become charged with oil droplets until the whole tissue assumes the peculiar yellow which is so distinct about the time of bursting of the follicle. And this colour it never loses until the time of its comj all the subsequent changes same anatomical structure and the same rela- tive position of parts is preserved. In the original preparation from which fig. 387. was taken, nothing served to distinguish the several coats better than their colour. The outer coat or theca folliculi was red ; the second coat, or ovisac itself, chrome yellow ; the now internal and newly formed coat was milk-white. It remains to describe the cavity in the interior of the follicle, which, though some- times obliterated, is more frequently found still existing at the fourth month of utero-gesta- tion. In the specimen represented in fig. 387. the cavity measured 3'" in diameter and con- tained a clear gelatinous fluid. In other cases a cavity at this time no longer exists, but the centre of the ovisac is occupied by a tough white substance, whose origin has just been explained. It will not be requisite to follow out minutely the remaining changes which the Graafian fol- licle undergoes. After the fourth or fifth month of pregnancy a certain diminution in size be- gins to be perceptible. The walls of the cavity nplete obliteration approaches; but through the subsequent changes of the follicle the approach nearer to each other, and the white lining becomes thinner, and begins to be folded into plaits which, radiating outwardly, are seen intermingling with the yellow colour of the proper ovisac (fig. 389.). The outer boundary of the follicle also now presents an irregular and somewhat angular and occasionally an oval outline. These changes proceed with much variation in different subjects ; but usually at the time of delivery the ovisac, though still yellow, has lost much of its brightness, and the cavity, if it had existed, is replaced by a solid white stellate cicatrix (fig. 389.) caused by the folding of the white lining Fig. 389. Graafian follicle two days after mature delivery. The white lining of the cavity (c,fig. 387.) is here folded into a stellate figure. It is surrounded by the dar- ker yellow ovisac (corpus Inteum'), whose outline is become angular. (After Montgomery.) membrane which bounded the ovisac on its inner surface. That the yellow coat is still vascular at this time is proved by the fact mentioned in the preceding page. In proportion as the entire generative or- gans subside into a quiescent state, so the re- maining changes in the ovary take place more rapidly. The yellow colour of the ovisac passes into a paler hue, and at last into white. The radiating cicatrix may still be traced for some time longer, until, at the end of four or five months after delivery, every appearance of this structure has ceased to be discernible. Certain physiological questions intimately connected with the foregoing history of the development and involution of the ovarian fol- licle may now be briefly considered. And first it may be asked — Does the discharge of ova from the ovary take place independently of sexual intercourse, or of any kind of infiuencefrom the male ? This question has long ceased to be agitated with reference to animals lower in the scale than the Mammalia. It need, therefore, now only be considered in its relation to the latter, including Man. And since many have recently undertaken to prove that Man and the Mam- malia constitute no exception to the general rule that in all classes of the animal kingdom which produce and emit ova the act of emis- sion of ova is independent of the male, so, whatever form the inquiry may now take, it would naturally have for its chief object the determination of the value of the evidence upon which such an assertion has been based. Now, the facility with which the process of ovulation may be observed in animals justifies OVARY — (FUNCTIONS). the expectation that in such a case the amount of objective proof, collected by those who have undertaken to establish a law of spon- taneous ovulation in Mammalia, would be sufficient to prove that law beyond the possi- bility of question. But when we turn to the principal writers who have devoted their at- tention to this point, with the view of collect- ing and critically examining such evidence, it must be confessed that the result is productive of a certain feeling of disappointment at the form in which the facts have been recorded, and the circumstances under which the obser- vations and experiments have generally been made. This is more particularly felt when, after examination of the evidence adduced, an unhesitating acceptance of the law, as one of universal application, is demanded. Be- fore, however, the question of universality is considered, it will suffice, for the purpose of proving the possibility of a spontaneous ovi- pont, to give one or two examples in which all the conditions necessary to establish this fact were observed, viz., absence of coitus, rupture of the ovarian follicle, and the presence of the unimpregnated ovum in the oviduct. The following case is related by Bischoff.* A lamb which had never received the male, and which had exhibited signs of " heat " about an hour previously, was shut up alone. On the following morning the male was admitted (for the purpose of testing the heat). He several times showed a desire for the coitus, but was prevented. The animal was killed the same afternoon, when it was found that a Graafian vesicle in the right ovary had burst. The spot did not project from the surface of the ovary, but attracted attention by the circle of red vessels surrounding the small opening which constitutes a familiar appearance in dogs and rabbits after bursting of a follicle. The diameter of this opening was about £'". As a matter of precaution, search was made for spermatozoa, in order to obtain the negative certainty that no coition had taken place, but none were found. The infundibulum con- tained a thread of mucus intermixed with granules resembling those of the membrana granulosa. The Fallopian tube was next carefully examined, and at a distance of 5'" from its entrance was found an ovum still surrounded by the cells of the granular disc, and possessing all the characters of the unim- pregnated ovarian ovum. But since in this instance the presence of the male was permitted, though coitus was prevented, as was also the case in one half of the instances recorded by Bischoff'in his ce- lebrated Treatise from which this example is quoted, it may be well to notice another ob- servation taken from Raciborski -f-, in which this possible objection was removed. A bitch which had never been covered, and was just commencing to be in heat, was kept shut up for eight days, apart from other dogs. * Beweis, p. 24. See next page, t De la Pubert^, p. 376. 567 It was then killed. Only one ovary was ex- amined, the other having been laid aside and forgotten. Three large follicles of a lively red occupied the entire surface of the ovary. One of these follicles was already shrunk, and presented at its summit a distinct fissure. In each cornu of the uterus, an ovum, the size of a poppy-seed, was found, surrounded by bloody mucus, — the one at a distance of about 2$ inches, and the other at f of an inch from the extremities of the tubes. Doubt- less, if the other ovary had been examined, at least one follicle would have been found to have opened there also. In order to show that the same process of discharge of the ovum, independent of sexual congress, may take place in the human subject, a case, recorded by Dr. Letheby, may be here quoted * : — " The body of a lunatic, aged 23, who had died in St. Luke's Hos- pital* was examined. She had been a patient in that institution for eleven months, under circumstances which deprived her of the op- portunity of associating with a male for a long period before her death. It was ascertained that the girl had quitted life during a men- strual period ; the cavity of the uterus, and the Fallopian tubes, contained a red, jelly-like secretion. On the outer and lower part of the right ovary was a dark livid spot, in the centre of which was a hole. On making a section of the ovary so as to divide it through the spot and an adjacent cicatrix, it was per- ceived that the hole led into a cavity which was surrounded by a dark-red tissue, and that the cicatrix communicated with a very per- fectly-formed corpus luteum, having a central cavity containing a dark-red clot. In the right Fallopian tube was discovered a little globular body of the size of a pin's head. This was seen, under the microscope, to consist, in its outer surface, of a mass of nucleated cells. At one end of this mass was a transparent ring, enclosing a rather opaque granular mass, in which there was an eccentric spot." The author had no doubt that this was the ovule consisting of the zona pellucida, yolk, and germinal vesicle. In another case related at the same time, and where the hymen was per- fect, similar results were obtained. The possibility of a spontaneous ovipont having been established by these and like in- stances which might be quoted, it becomes important next to determine how far the law just enunciated is universal in its application ; we may therefore inquire, — Does the discharge of ova from the ovary al- ways take place spontaneously, and independent of sexual intercourse ? It is in endeavouring to determine this question, so far as the attempt has been made to base this law upon observations and experi- ments on animals, that the difficulty to which 1 have just adverted is experienced ; for, whilst there is no lack of argument upon the subject, it must be confessed that the number of well-recorded instances proving a spon- * Phil. Trans, 1852, pt. i. p. 5. o o 4 568 UTERUS AND ITS APPENDAGES. taneous ovipont in mammals is exceedingly small. It will suffice for illustration to observe the manner in which this question has been han- dled in the celebrated works of Bischoff*, Raciborskif, Costef ,and Pouchet.§ The first only of these authors has given in detail the observations and experiments upon which he has endeavoured to found a law of spontaneous ovulation in the Mammalia. In several of these the coitus was permitted ; and although it is rendered highly probable, from the cir- cumstances narrated, that in some this had no effect in producing the discharge of ova, yet the introduction in any form of the only con- dition that could vitiate the experiments de- tracts certainly from their value. In five, however, of Btschoff's experiments it was known that coitus had not occurred, and in three of these ova were found discharged, ac- companied by the usual appearances in* the ovaries indicative of the recent rupture of the follicle. || In a fourth case, the state of the ovaries left no doubt that the ova, which could not be found, had escaped; while a fifth case was examined before the ova had escaped. To these Bischoff adds an example of the ovipont in an animal, in which it was only probable that no coitus had occurred. The work of Raciborski contains a single example, which has also just been quoted. The works of Coste and Pouchet contain no examples of a spontaneous ovipont in ani- mals, but the observations of each of these authors are given in the form of results. Each work contains a minute description of the process of ovulation, drawn apparently from separate observations ; but these descriptions are not accompanied by any detailed ex- amples, nor any statement of the means used to render these observations proofs of an ovi- pont, independent of coitus. But all these authors agree in stating that ovulation occurs independently of sexual union, whilst they differ as to the decree of strictness with which the universality of this law is enforced. Pouchet demands that the law should be received without any excep- tion, and observes with surprise the " unac- countable vacillations" of those among his predecessors who yield to it only a partial assent. But in the absence of any extensive series of well-recorded observations, whose numeri- cal force shall be such as to compel a uni- versal acceptance of the law, it is not sur- prising that some who regard it as having been too hastily framed, and as too rigid in its ex- clusiveness, should withhold their full assent to it. For let it be conceded that the ova, when they have attained their complete deve- lopment, escape naturally from the ovary, the rupture of the follicle not necessarily requiring * Beweis der von der Begattung unabhilngigen periodischen Keifung und Loslbsung der Eier, &c. 1844. t De la Puberte, et de la Ponte periodique. 1844. t Histoire du Developpement. 1847. § Theorie positive de TOvulation spontanee. 1847. j| One of these cases is given above. the intervention of the male, should it there- fore be inferred that the latter is completely inoperative when exercised on opportune oc- casions ? In this form the question is put by Coste, who maintains that although the coitus may not be the essential cause of the rupture of the follicle, yet it undoubtedly has the power to precipitate that event, and even to prevent its failure. He further considers that there is this difference between the fecundated female and one in whom impregnation does not take place ; that in the former the rupture of the follicle is prompt, whilst in the latter it is tardy, or even in certain cases fails to occur. In order to support this view, Coste cites two observations upon the rabbit. In the first of these, the animal was in heat, and mani- fested great ardour for the male, but coitus was not permitted. It was kept for forty- eight hours, and then killed. The genital or- gans were highly congested. Six follicles in one ovary, and two in the other, were appa- rently ready to burst, but no rupture had yet taken place. In the second experiment, the animal remained in heat for three days ; on the fourth day the heat ceased, and on the fifth it was killed. The organs were in the same condition as in the last case, but no follicles had burst. Coste attributes the ab- sence of rupture in these cases to the preven- tion of the coitus at a time when, if permitted, it would in his view have determined that event. In whatever light these observations may be viewed, they are important as showing that an animal may sometimes advance far in the pe- riod of heat, and even pass through it without any ova escaping from the ovary ; but it would require a very much greater number of parallel observations to prove by such negative results the effects of the sexual congress in determin- ing the act of the ovipont. And it is matter for regret that this point has not been more clearly determined ; for whilst no satisfactory results can be looked for from any observa- tions upon this part of the subject in Man, this is eminently a question capable of being deter- mined by experiments on animals. All the earlier observers who directed their attention to the condition of the ovaries in relation to reproduction bear unconscious testimony to the fact that the time at which the ova quit the ovaries bears no strict relation to the act of coition. Barry states that, taking the coi- tus as the starting-point of his reckoning, he was obliged to sacrifice a score of rabbits be- fore he succeeded in meeting with one instance of the ovum at a particular time after its es- cape, and he had almost given up the attempt in despair. If means be used to prevent the contact of the seminal fluid with the ova after their dis- charge from the ovary, or to prevent its arrival at the latter organ before rupture of the fol- licle, this does not affect the immediate condi- tion of the follicle. The number of ruptured Graafian vesicles which have been found, after experiments made by placing ligatures upon OVARY — (FUNCTIONS). the tubes before coitus was permitted, has usually amounted to the sum of the ova dis- charged. If one side of the uterus be tied, the ova found in that cornu will not have been impregnated, but those on the free side will be developed. The number of ruptured follicles in each ovary will agree with the number of ova found in the corresponding tubes; but no difference will be perceptible between those on the impregnated and those on the unimpregnated side of the uterus. The contact, therefore, of the seminal fluid with the ovary has nothing to do with the discharge of the ova, or with the formation of a " corpus luteum." The only question that can here have place is, whether the excitement of the coitus, or the contact of the seminal fluid with the inner surface of the vagina and uterus, has any influence in precipitating the discharge of ova from the ovary when they are ripe for impregnation. This, however, is, in the present state of our knowledge, an un- settled point. By all the earlier observers down to Barry, it was assumed that the coitus was the sole determining cause of the ovipont. By most physiologists since that time the coitus has been regarded as having nothing to do with the discharge of the ova, or only a limited power has been ceded to it, as in the view of Coste just detailed. So far as numerical amount of recorded observation goes, it may be asserted that the spontaneity of the act of emission of ova, inde- pendent of sexual intercourse, has been more fully and satisfactorily proved in Man even than in animals. In the works and essays upon this subject, to which reference is given in the preceding page, a large amount of evi- dence will be found ; but since some proofs of this fact have been already given, and since it is proposed again to return to the subject in considering the question of menstruation in its relation to ovulation, it will not be ne- cessarv to pursue the subject further here. (See page 666.) In tracing the process of ovulation, it will have been observed that the ovarian follicle passes through a series of changes, so gradu- ally progressive and of such a definite cha- racter, that the knowledge of these may be turned to great account in any investigations relating to the ovipont ; for, next to the dis- covery of the ovum itself, whether in the ovary, Fallopian tube, or uterus, the condition of the capsule, from which it is about to be or has been already discharged, will afford the best evidence as to its probable locality and condition, even should the ovum not be found. Doubtless, one of the greatest impediments which has been encountered in investigations of this class arises from the extreme diffi- culty, and often the impossibility, of finding the ovum in many situations on account of its minute size. Hence, in the absence of this demonstrative evidence, which cannot always be obtained, any other, which, though only inferential, may be made available for a like purpose, is of great value. Wanting the ovum, therefore, the state of the ovicapsule 569 may be made, in part at least, to supply the evi- dence which is deficient. Now it has been shown that, whatever affects the ovum, to de- termine its development or the converse affects in a like degree the follicle from which it had been discharged, not on account of any appa- rent sympathy between the ovum and the fol- licle which once contained it, but from the whole generative track being more or less brought under the power of one common sti- mulus, felt alike by all the parts that are em- ployed for the nutrition and protection of the ovum. It will be desirable, therefore, now to determine what evidence the condition of the ovarian follicle affords, first, as to the previous escape of an ovum, and secondly as to the probability or certainty of that ovum having been impregnated or otherwise. But since it is desirable to fix the value of certain terms which are commonly employed to designate particular states of the follicle, it will be need- ful, first, to determine, What is a corpus luteum ? This term, as Raciborski has observed, is indicative of the infancy of science. It be- longs to a period when anatomists were in the habit of designating by the word body or corpus any part of the animal economy whose nature or relation with other parts they did not comprehend, adding to this some dis- tinctive title drawn from the general appear- ance of the part. Hence the terms corpus striatum, corpus cal/osum, corpus luteum. It is an unfortunate circumstance that such a term was ever applied to the Graafian follicle, and the more so since it is often employed without any definite meaning. The Graafian follicle in its progress to- wards full development, and previous to its rupture, has been described as becoming yel- low. This fact has been long known. It is stated by Home, Baer, Valentin, Wagner, and Bischoff. The cause of the yellow colour has been fully explained. After impregnation this yellow colour becomes still more conspi- cuous on account of the greater thickness of the ovisac or inner coat of the follicle, which is the seat of the change producing this colour. From the greater distinctness, larger size, longer duration, and other pecu- liarities of the follicle after impregnation, an artificial distinction has been made between the follicle in this state, and all other forms of it, in which it exhibits the yellow colour. The former are arbitrarily called " true," and the latter " false " corpora lutea. But there is as little reason for the use of the last term, as there would be for denominating a child a false man; for that which is commonly designated the "true" corpus luteum is the follicle in its largest condition of growth, as it appears after impregnation ; whilst in all other conditions, when it has not been stimu- lated to full growth by impregnation, and whether before or after rupture, it has been called a "false" corjjus luteum so long as it possesses the yellow colour. This distinction, therefore, as far as regards the terms em- ployed, is not only unscientific and arbitrary, 570 UTERUS AND ITS APPENDAGES. but is calculated to mislead by suggesting the idea that the so-called " true " corpus luteum is a totally different body from the " false," whereas these terms actually represent the same body, only in different stages of growth or decay. But practically it becomes a ques- tion how far it may be possible to determine, from the physical appearance of the follicle, whether impregnation has taken place. And this question is a very important one, espe- cially in its obstetric and forensic bearings. From the account already given of the several stages of growth and decay of the ovisac, it will have been seen that the yellow colour is common to all these alike, with the exception only of the earliest and the very latest stages. It alone, therefore, can afford no distinctive evidence upon the subject. But, in combination with other signs, the yel- low colour, by its extent, may be made avail- able to distinguish those cases in which im- pregnation has occurred ; for when this is the case the ovisac, as stated, continues to increase in thickness ; a greater abundance of yellow deposit takes place in its tissues; the follicle, instead of shrinking and disappearing in the course of one or two months, continues to be visible for fourteen or fifteen months. It acquires a new coat which lines its cavity, or else this cavity is entirely closed by a coa- gulum which becomes organised and solid ; it presents the convoluted appearance which gives it a resemblance to the cerebral convo- lutions, and this convoluted condition gra- dually passes into one which is characterised by the presence of rays proceeding from a centre. Finally, the whole body constitutes a resisting and more or less solid mass, which can at once be detected by the touch, before the ovary is opened. The distinctions, therefore, are chiefly those of degree : the greater solidity ; the greater thickness of the yellow walls ; their more marked convolutions ; the long persistent cavity, round or oval at first, and subsequently stellate ; the milk-white membrane lining the cavity, when the latter exists, or the white dense mass occupying its place, resulting from the transformation of the clot. These last characteristics of the so- called true corpus luteum, viz., the cavity lined by the white membrane or the solid white centre, as well as the large central stellate ci- catrix, may be regarded as absolute and not comparative distinctions, for they are not found in the follicle in process of involution when impregnation has not taken place. With regard to scrofulous tubercles, which have been often enumerated among " false corpora lutea," it is probable that some of the conditions of the ovisac now described have been hastily set down to this score, without sufficient examination ; for although scrofula may possibly affect the ovary, as it does the testis, yet a formation there of distinct scrofulous tubercles, unless they are abundant in other parts of the body, is, I am satisfied, a rare, if not an unknown, occurrence. No doubt, however, need at any time exist as to the nature of such bodies, since, if the bright yel- low colour of the ovisac is not sufficiently marked, as in those cases where they have be- come pale, and more nearly approaching the buff colour of tuberculous matter in general, the microscope will at all times determine the question, for in respect of composition there is nothing in common between tuber- culous matter and the ovisac in any of its natural stages of growth or decay. Setting aside morbid states, nothing is ever seen in the perfectly healthy ovary except the stroma and ovisacs or Graafian vesicles in different stages of development or decline. These may be arranged in three series : Ascending Series. 1. The simple undeveloped ovisac, before it has acquired an indusium from the stroma of the ovary, or from the walls of an already developed follicle, in which it may be formed. It requires at this time the microscope for its examination (fig. 373.). 2. The ovisac after it has acquired its outer capsule, by union with which it has become a Graafian follicle. 3. The Graafian follicle of the size of a hemp seed, or rather larger. It contains oil gra- nules in the coats of the ovisac, but not yet in quantity sufficient to produce a yellow colour. In this state numerous follicles are seen in sections of every healthy ovary during middle life (figs. 370. and 372.). 4. The follicle when it is approaching the surface of the ovary. It is enlarging, and its inner coat or ovisac has now a yellow colour. 5. The ripe follicle which is about to rup- ture and discharge an ovum. It is always found at the surface of the ovary, projecting often to a distance of 3-4///r. It is covered by numerous veins, and in the centre of the most prominent part the coats of the follicle, as well as the ovarian coverings, are thinned and partly absorbed. Their thinness permits the contents of the follicle to be partly visible, and thus is produced a brownish red colour at this spot. The follicle contains blood or a bloody fluid, and sometimes a clot. The cavity is of considerable size, 4-6//x. The inner coat is of a bright yellow colour, and ex- hibits slightly wavy folds (figs. 380. and 381.). 6. The follicle which has already ruptured. An irregular lacerated opening extending £-2/// is perceptible in the centre of the attenuated part, through which the ovum, together with that portion of the membrana granulosa which lay beneath the seat of the rupture, has es- caped, or is about to escape. The follicle is beginning to collapse. Its walls, no longer distended, become folded into numerous small plaits, producing, on section, the ap- pearance resembling cerebral convolutions. The cavity is consequently diminished. It is empty, or contains a little bloody fluid or a clot (fig. 385.). Descending Series. A. Not pregnant. 7. In the follicle which has recently burst, shrinking has commenced. The yellow ovisac is much plicated. The cavity contains a clot which is becoming pale, and exhibits under the OVARY — (DEVELOPMENT AND INVOLUTION). microscope distinct fibrillation, or the cavity is empty and much contracted. 8. The shrinking having rapidly progressed, the ovisac exhibits deep plications, and the rays are beginning to form, but the yellow colour is still distinct. 9. The cavity is nearly or entirely oblite- rated. The yellow colour is gone, but the rays remain, and the collapsed follicle now forms a white stellate body with a small cen- tral point (fig. 372. h). 10. The follicle itself is reduced to a mere point in which none of the foregoing characters can be traced. Descending Series. B. After Impregnation. 11. The follicle has not materially dimi- nished in size. The lacerated opening is closed. The yellow coat is much plicated, and the clot when present shows fibrillation, as in No. 7., or the cavity is empty. 12. The follicle has acquired greater firm- ness and solidity. The yellow ovisac is much increased in thickness. The folds are not so numerous, but are deeper, though not quite so distinct. Vessels contained between the folds appear to pervade the yellow coat. The white lining of the cavity is formed, and within it is a clear fluid, rather viscid, (fig. 387.), or the centre of the yellow ovisac is solid, and exhibits no cavity. 13. The central cavity is nearly or entirely obliterated. In the latter case a solid white body occupies its place, extending into the yellow mass in divergent rays. This arises from the plication of the white lining, by which process the cavity is closed. The co- lour of the principal mass is now a dirty yellow ; it is somewhat reduced in size, and its outline is oval or irregular (fig. 389.). 14. The more prominent features observable in the last condition may still be faintly traced. In size the body measures 2-3'". It is of a pale white, and is chiefly distinguishable from the surrounding stroma by the absence of vascularity in its tissues. Its solidity is gone. To return, then, to the two questions which led to the foregoing considerations as neces- sary to their solution, viz. — What evidence does the condition of the ova- rian follicle afford, first, as to the previous es- cape of an ovum, and secondly, as to the pro- bability or certainty that that ovum has been impregnated or otherwise ? It may be concluded that whenever the follicle presents the appearances exhibited in the first series down to and including No. 5., the ovum has not escaped ; although it may not be detected, either on account of the difficulty of finding so small a body, or else because it may have perished by absorption or decomposition. In the condition No. 6., an ovum has just escaped, or is in the act of escaping. None of these conditions of the follicle a~ffbrd the slightest evidence of previous impregnation. They have all been repeatedly observed both in Man and animals where the coitus has never occurred. Between No. 7. and No. 1 1. it may bediffi- 571 cult to draw a positive distinction. No con- clusion regarding the question of previous fecundation, derived from the state of the fol- licle during the first fortnight after the escape of an ovum, would be absolutely safe ; al- though the difference between the unimpreg- nated and the impregnated is such as to afford in every instance at least strong presumptive evidence, for the follicle shrinks rapidly in the former, while in the latter it undergoes little or no diminution in size. But after this period there can be no ques- tion as to the prior occurrence of a fecun- dating coitus. Every follicle presenting the conditions described in Nos. 12, 13, and 14 has discharged an ovum, which has been after- wards impregnated. Every follicle in the states described in 8, 9, and 10 has discharged or has contained an ovum which has perished. But this proves only that fecundation has not occurred. It affords no evidence whatever that the coitus has not obtained. Lastly, it may be observed that if, as is sometimes the case, the follicle fails to com- plete the process of rupture after the first steps of preparation have been made, the ovum may perish or be absorbed without being dis- charged, and the follicle will then shrink and become obliterated, as in the first series of changes. And it is further noticeable that although the number of Graafian follicles ex- hibiting the appearances indicative of the dis- charge or fecundation of ova, may generally be taken to represent the number of ova also actually discharged or fecundated, yet this will not always furnish a safe guide, because one follicle may contain two ova, or one or more ova may have escaped the influence of the coitus which had fecundated the rest. The number of ruptured or altered follicles there- fore will in the first case be less, and in the second greater, than the number of ova or foetuses found in the oviducts or uterus. DEVELOPMENT AND INVOLUTION OF THE OVARY. The Origin of the Ovary, and the Alterations which it undergoes at different Periods of Life. The ovary takes its origin in a separate portion of blastema, quite independently of the Wolffian body, with which it is in close contact. It is not indeed until after the de- velopment of the Wolffian bodies has made considerable progress, and about the time at which the kidneys first appear, that, according to the observations of BischofF on the mam- malian embryos generally, the ovaries are first perceptible. In the human embryo the ovary cannot be discerned earlier than the 5-7th week. Nor is it possible at the time of its first appear- ance to distinguish the ovary from the testis. Hence the term "generative gland " has been proposed by Kobelt as the most appropriate designation for a structure which, according to him, is then capable of being converted into either organ indifferently. In a human em- bryo of the fourth week, of which I have given a description in the Transactions of the 572 UTERUS AND ITS APPENDAGES. Microscopical Society of London *, no trace of an ovary or generative gland was discover- able, but only slight indications of two linear- shaped bodies occupying the dorsal and lum- bar regions on either side of the vertebral column, representing the corpora Wolffiana. In another embryo measuring 5'" in length, the generative gland could just be discerned in front of the supra-renal capsules and kidneys, but its form could be only indistinctly traced. In an embryo, however, which measured 8'''' in length, the gland had already assumed dis- tinctly the elongated figure characteristic of the early formation of the ovary. It mea- sured 0*8/r/, and its position was oblique, or intermediate between the perpendicular direc- tion of the Wolffian body and the horizontal one of the fully formed ovary. In an embryo of three months the generative gland or ovary still retained the oblique direction. Its length was 2"', and its breadth G'4"'. From this period the gland, which now be- gins to assume more decidedly the character of an ovary, gradually acquires the horizontal position in which it is found at birth (^g.440.). In the foetus at term the ovary has usually attained a length of 4-5"', and a breadth of H-2'"(/g.441.). Itsfigureisan extended oval, with flattened sides and base. These meet to form a triangle, whose basal margins are sinu- ous and sometimes indented. At the age of three years, (fig. 442.) the ovary attains a length of 10-1 2"', still however preserving its elongated form, with irregular or slightly in- dented margins. This peculiarity of a foetal con- dition the ovary gradually loses as the period of puberty approaches, when it grows more rapidly and acquires the form and dimensions already described as characteristic of the ma- ture organ (fig. 369.). At this period of life, however, no feature of the ovary is more sub- ject to variation than its form. Even for some time after the catamenia have been established, the elongated figure is often seen to have been retained, although the rounded or gibbous outline is more commonly observed by the time that adult age is attained. The ovary is now full and plump ; its sur- face up to the time of puberty has remained uniformly smooth, even, and shining, and its investing tunics are unbroken.f But it has * Vol. iii. part ii. p. 65. t In reference to the human subject, the univer- sally received opinion regarding the discharge of ova by rupture of the ovisac, as an occurrence which com- mences only at or after puberty, has been called in question by Dr. Ritchie, who, a'fter detailing a series of observations upon the condition of the ovary at various periods of life, asserts that " the Graafian vesicles contained in the ovaries prior to menstru- ation are found, as they also are in every other period of life, in continued progression towards the circumference of the gland, which they penetrate, discharging themselves by circular-shaped capillary- sized pores or openings in the peritoneal coat ; the presence of the catamenia being thus no indispen- sable prerequisite to their rupture." l It should be observed, however, that the facts adduced by Dr. Ritchie do not appear to bear out very clearly the conclusions which he has drawn from them. 1 Lond. Med. Gaz., vol. xxxiv. p. 253. been seen that, from puberty onwards, through these two tunics of the ovary, the ova pe- riodically escape by a process of dehiscence, resulting from an absorption and rupture of these tunics. The effect of these repeated lacerations is twofold. The surface becomes scarred in all directions by the closing up of Fig. 390. Ovary about the time of cessation of menstruation. (Ad Nat.) the lacerated openings, whilst the successive discharges of the contents of the ovisacs gradually diminish the bulk of the entire or- gan (Jig. 390.). In proportion as age advances, these cicatrices and indentations become still more numerous, and the once smooth and plump ovary is converted into a small corru- gated wrinkled body full of pits and tortuous Fig. 391. Ovary in old age. lines (/g.391.). When sections are made of the ovary in this condition, it is found that all traces of the Graafian follicle have disappeared; or one or two only may be observed, degene- rated into little masses or sacs of cartilaginous hardness. More commonly, however, nothing now remains but a dense parenchyma. Besides these changes in the form of the ovary and the condition of its component parts, great alterations also take place in its vascular supply. In early life, and especially from the establishment of puberty up to the critical age, the organ is abundantly supplied with blood-vessels, which are seen everywhere both in the proper parenchyma of the ovary, and also upon the walls of the ovisacs. These have been described as undergoing enlarge- ment, and probably increasing in number in the neighbourhood of the spot at which the rupture of the follicle occurs. Not only, however, is there a local hypersemia in these situations at each recurrence of the ovipont, but the entire ovary receives a larger supply of blood on these occasions. But when the process of ovulation has entirely ceased, the tissues begin to suffer the wasting of age, the ovary partakes in the general state of pallor of the other pelvic viscera, and the ovarian vessels carry only as much blood as will suffice for the bare nutrition of the shrivelled organ. OVARY — (ABNORMAL ANATOMY). 573 ABNORMAL ANATOMY OF THE OVARY. Effects of extirpating the Oviry. — A natural deficiency of the ovary together with the oviduct of one side is known to prevail in the class Aves, but this deficiency, which is oc- casioned only by a want of development of one half of the generative organs previously existing entire in the embryo, does not affect the reproductive power of birds. Mr. Hunter, wishing to determine the effect of extirpating one ovarium upon the number of young produced in Mammalia, procured two young sows of the same farrow, and having removed a single ovarium from one of them, he kept both animals under the same circumstances, in order to observe the comparative effects of breeding upon them. They commenced breeding when two years old. The spayed animal took the boar earlier than the perfect female, and both continued to breed at nearly the same times. The spayed animal continued to breed until she was six years old, and in that time she had eight farrows, producing in all seventy- six pigs, but she did not take the boar after- wards. The perfect sow continued breeding until she was eight years old, and had thirteen farrows, yielding one hundred and sixty-two pigs. She then ceased to breed. The result therefore of this experiment was, that the perfect animal continued to breed two years longer, and produced in all ten more than double the number of the spayed one, although she had not double the number of farrows. But few opportunities have occurred for observing the effects produced by the removal of the healthy ovaria upon the human female. The case in which Mr. Pott removed both these organs at the same tune constitutes the best example on record. A young and healthy woman, twenty-three years of age, was received into St. Bartho- lomew's Hospital, on account of two small swellings, one in each groin, which had for several months been so painful as to prevent her from following her occupation as a servant. The swellings, which were not inflammatory, were soft, uneven upon their surface, and moveable. They lay directly upon the out- side of the tendinous opening of the oblique muscle through which they appeared to have passed. The woman was in full health, was large breasted, and menstruated regularly. On account of the inconvenience occasioned by the presence of these tumours in the groins, Mr. Pott was prevailed upon to re- move them. They were found upon exami- nation to be the two ovaria which had de- scended in the form of a double inguinal hernia. The woman subsequently enjoyed good health, but became thinner and more apparently muscular; her breasts, which were large, were gone, nor did she ever menstruate after the operation ; the last observation of her having been made several years subsequent to that event.* Deficiency of the Ovary. — Complete con- * The Chirurgical works of Percival Pott, by Earl, vol. ii. p. 210. genital absence of both ovaries, except in the case of the non-viable foetus, is of extremely rare occurrence. It is almost always asso- ciated with deficiency or imperfect formation of the uterus, and generally with incomplete development of the vagina, nymphae, clitoris, and mammae. The sexual appetite in these cases is wanting. Menstruation is absent ; the secondary sexual characters are but feebly expressed, and there is of necessity a total in- aptitude for reproduction. The ovary may, however, be deficient on one side only, without any of these accom- panying conditions. There may be nothing externally to mark the defect, nor is there necessarily here any impediment to the ex- ercise of the sexual function. Arrest of Development. — The ovary, like the uterus, long retains its infantile condition, but as the period of puberty approaches it expands and soon attains its full size. This change, however, may not occur. The ovary may cease to grow after the third or fourth year, and, under these circumstances, the whole organism manifests a corresponding tardiness of development. An interesting example of this is preserved in the museum of King's College. The preparation consists of the entire internal organs of a young wo- man who died at the age of nineteen without having menstruated. The ovaries, as well as the rest of the organs, are no larger than those of a child of three years (see^?g. 465.). In these cases the mammae are small, the ex- ternal organs only partially developed, and the whole frame is formed upon a feeble scale. Atrophy and Hypertrophy. — Atrophy has been shown to be one of the conditions at which the ovary inevitably arrives when a certain period of life is passed. It is under these circumstances a normal condition, just as the state last described is also a normal condition when associated with a certain epoch, but both become abnormal states when they occur out of their usual course. Thus, an early atrophy of the ovary on both sides will of necessity bring with it a premature failure of procreative power, although an atrophied state of the organ on one side only, like atrophy of one testis, will but little, if at all, affect this power. Of hypertrophy of the ovary a more par- ticular account will be given in the descrip- tion of morbid growths and abnormal deve- lopments of its special parts. Displacements of the Ovary. — The ovary, in consequence of its peculiar mode of attach- ment to surrounding parts, enjoys great free- dom and range of motion. This is rendered most conspicuous, when, during the gradual enlargement of the gravid uterus, the ovary is carried upwards from the pelvic into the abdominal cavity. Under these circumstances the ovary certainly vindicates the character assigned to it by the older anatomists, of being an appendage to the uterus, for it necessarily follows the movements of the larger organ to which it is attached. Thus, the ovary is sometimes a pelvic and sometimes an abdo- 574 UTERUS AND ITS APPENDAGES. minal viscus. But it may be displaced normal position in either of these from its position in either of these cavities under various circumstances. The causes of such displacements are chiefly, inflammation of the surface of the ovary terminating in adhe- sions, displacements of the uterus, and hernise. As a result of inflammation of its peritoneal covering, the ovary may be bound down to the side of the uterus, or Fallopian tube, to the recto vaginal pouch, to the brim of the pelvis, to the colon, to the convolutions of the ileum, or to the omentum. The displacements of the uterus which occasion a dislodgement of the ovary from its normal position are, retroversion, inversion, and procidentia, or complete prolapsus. In retroversion the ovaries are carried downwards along with the uterus into the hollow of the sacrum, where they occupy a position on either side of the principal organ. In inversion of the uterus, the ovaries, to- gether with the Fallopian tubes, fill the in- terior of the artificial pouch, which is formed by the reversement of the organ ; whilst in extreme prolapsus the ovaries, together with the uterus, escape almost entirely from the pelvis, and occupy the sac which is formed by the inverted vagina. But the most remarkable displacements are those in which the ovary constitutes a true hernia. Such a hernia may consist of the ovary only, or may include other organs, as the Fallopian tubes, uterus, intestine or omen- tum. A true hernia of the ovary alone is of comparatively rare occurrence. It may hap- pen on one or on both sides, and may be either congenital or acquired. The celebrated case of Mr. Pott was an example of a double inguinal ovarian hernia. And this appears to be the form under which this singular dis- placement has been most frequently met with. In these cases the ovary constitutes a solid tumour of the size of a pigeon's egg, which may be detained at the ring, or lie within the inguinal canal, or even descend to the labium. An example of this kind of hernia, in which the left ovary has for many years occupied the inguinal canal, has recently come under my notice. Deneux*, who was at the pains to search out all the cases on record up to his time, has collected examples also of crural, ischiatic, umbilical, ventral, and vaginal hernia of the ovary, and to these Kiwisch has added a case of hernia through the foramen ovale. Diseases of the Tunics. Inflammation of the ovarian tunics, and parti- cularly of the peritoneal coat, is most commonly associated with acute puerperal metritis. But inflammation, both in the acute and chronic form, may affect the ovary independently of the puerperal state. The resulting anatomical changes in the coats of the organ are vascular congestion in various degrees ; fibrinous exu- dations upon their surface, followed occa- sionally by the formation of artificial bands or adhesions with surrounding parts ; and * L. C. Deneux, Recherches sur la Hernie de 1'Ovaire. 1813. chronic thickening of these coats, whereby the original smooth and even surface, (Jigs 368. & 369.) characteristic of the ovary in early life, is lost. When inflammation of the ovary has ad- vanced to the suppurative stage, and this organ is converted into a bag of pus, the coats may have become so attenuated and softened as to burst when the attempt is made to lift the parts from the body after death. Ulceration. — Rupture. — In the case of large collections of fluid within the ovary, as for example in large abscesses or in ordinary ovarian dropsy, the surface of the ovary fre- quently inflames and contracts extensive adhesions with surrounding parts, and if the latter happen to be hollow viscera, such as the intestines, uterus, or bladder, a fistulous communication may be established between them and the sac of the ovary, through a process of ulceration or absorption of the common partition wall, and the contents of the ovary may become discharged externally. Or it may happen that by a similar attenua- tion and rupture, or by a process of ulceration and absorption of these tissues, the ovarian walls give way, in some parts of their free surface, and their contents escape into the abdominal cavity. Hypertrophy of the ovarian tunics is almost constantly observed in considerable enlarge- ments of the organ, from whatever cause they may arise. In the case of large ovarian cysts, before adhesions have been occasioned by the pressure of surrounding parts, the peritoneal coat of the ovary, though much thickened, retains its smooth, shining, external surface. It may be generally stripped off with ease, and displayed as a dense white membrane of unequal thickness, but having undergone no further change than that of a generaf hyper- trophy of its ordinary component tissues. The tunica albuginea in like manner becomes thickened by simple increase of its ordinary constituents, but in the case of very large, and particularly of unilocular cysts, the cyst wall becomes so intimately blended with the common ovarian investment, that it is impos- sible to determine how much of the now united membranes was originally furnished by the tunica albuginea, or ovarian stroma, and how much by the proper wall of the cyst. The hypertrophy in these cases is often so con- siderable that the boundary walls of a large ovarian cyst may measure one or two inches or even more in thickness in some places. Ossification. — Patches of ossific matter more or less extensive are occasionally found scattered over the surface of ovarian cysts. It is probable, however, that these are de- posited in the first instance upon the inner surface, or in the proper walls of enlarged cysts, and subsequently extend to the proper coverings of the ovary, and that the fibro- cartilaginous degeneration which these cyst walls sometimes exhibit, also commence in the original cyst, and proceed from within outwards. Diseases of the Tissues, Hypercemia of the ovary may be limited to OVARY — (ABNORMAL ANATOMY). 575 the parenchyma, or to the walls of particular follicles, or may affect all these parts together. Hyperaemia of particular follicles, with con- siderable enlargement of the sac and effusion of blood into the cavity of the follicle, is not unfrequently observed as an abnormal condi- tion. But hyperaemia of single follicles with effusion of blood into the cavity has been already described, as being also a natural state of the Graafian follicle, which is preparing for dehiscence and discharge of an ovum.* It may be asked, therefore, in what respect does the normal differ from the abnormal state, and by what characteristics may the one be distinguished from the other ? It appears to me that Rokitansky, in the account which he has given of hyperaemia of the Graafian follicle f, has included under one head both the natural and the morbid condition ; for his description will very well apply to the rising follicle, in its second stage, when the escape of blood into the cavity has been shown to be a normal, and in some animals a constant occurrence. The presence, therefore, of blood within the follicle, for the reasons al- ready fully given (p. 556.), must not be regarded as necessarily affording evidence of a morbid state. There are, however, certain pecu- liarities in the condition of the unhealthy fol- licle, by which it may be distinguished from that which is natural. The natural follicle, when preparing for dehiscence, is always near the surface, and often projects considerably above the level of the ovary (J?g.380.). Its coats are unequally thick ; the thinnest portion being always found at the most prominent point of the follicle. There is considerable vascularity about this point, plainly visible externally, and here the process of attenuation and ab- sorption continues to be progressive until the sac spontaneously ruptures. The walls of the follicle are at this stage of a bright yellow colour. The liquor folliculi is either clear and limpid or intermixed with blood, or the centre of the sac is filled by a coagulum, which is at first bright red, and afterwards becomes pale, and at length nearly white. The coagulum may adhere to the walls, and undergo fibrillation and subsequent conversion into a solid body, or into a dense white membrane, or it may be rapidly absorbed. On the other hand, the morbid follicle, al- though it may not exceed nor even equal in size that which is passing through its normal changes, may yet be distinguished by many characters which are the converse of those just described. The morbid follicle is often not peripheral, but is more or less central in its position in the ovary. It may attain to the size of £ or £ of the ovary, without ne- cessarily causing any distinct prominence above the surface (especially when occurring singly). The walls are equally thick, and exhibit at no part any evidence of attenuation or absorp- tion. No preparation for rupture is indicated externally by any peculiar arrangement of ves- * P. 556. t Manual of Pathological Anatomy. Sydenham Society. Vol. ii. p. 328. sel, or by any marked increase of vascularity. The walls do not exhibit the remarkable yellow colour nor the cerebral foldings characteristic of the advancing normal ovisac, but the tis- sues of which they are composed are simply those of the undeveloped Graafian follicle. The contents of the sac are neither the clear liquori folliculi, nor the bright clot, nor the decolorised fibrin, but generally a collection of dark coffee-ground matter, resulting from the admixture of a quantity of decomposing blood- corpuscles and fragments of membrana gra- nulosa intermixed with a dirty fluid. On washing out these contents, the walls of the cyst, if the ovary has been injected, are seen to carry numerous vessels, irregularly arranged, but never presenting that rich network of capillaries which are visible after a successful injection of a healthy ovisac progressing to- wards rupture, especially in those cases where the quantity of yellow oil is not so great as to obscure these vessels altogether. By these characteristics the morbid ovisacs may generally be distinguished from those which are healthy. There is enough of simi- larity between them to prove their identity of origin, and enough of dissimilarity to show their divergence from a common starting point ; the healthy follicle proceeding onward through a course of different changes, which have been already fully described ; the morbid follicle exhibiting an apparently unlimited power of growth and deformity, "such as will be pre- sently more fully noticed. Fig. 392. exhibits the morbid follicle in one of its earliest stages of growth. It may be con- trasted viiihjigs. 381. and 385., for the purpose of showing the points of difference which have just been described. In Jig. 392. the morbid follicle occurs as a single cyst in the midst of Fig. 392. Ovary containing a morbidly distended Graafian follicle in an incipient stage. The rest of the organ 'is healthy. (A otherwise healthy tissues. Although occupy- ing more than £ of the entire ovary, it scarcely disturbs the even outline of that organ. Its coats are of uniform thickness throughout. There is no attenuation nor preparation for dehiscence at any particular spot, nor external sign of increased vascularity in one point. But the walls of the follicle contain nume- rous vessels, distributed nearly equally over their surface. The cavity is filled with loose flocculi of a dark chocolate colour, consisting of decomposing blood clot mixed with patches 576 UTERUS AND ITS APPENDAGES. of membrana granulosa. The walls of the follicle are not yellow, and contain no oil globules. They * are slightly thicker than those of the healthy follicle. Their compo- nent tissues are precisely those which have been already described as characterising the ovisac in its normal condition ; the chief bulk of their texture being made up of gra- nules and embryonic fibres intermixed with a few developed fibres of ordinary white fibrous tissue. Such a condition may, for want of a better designation, be regarded as hyperaemia of the follicle, or it might perhaps be more appro- priately termed hypertrophy of the follicle ; but in whatever light it may be regarded, it constitutes one of the early stages of those enormous growths, of which more will be said hereafter. A more extensive form of congestion, affect- ing the parenchyma of both ovaries, and as- sociated with a like hyperaemic condition of the uterus, may be sometimes observed about the period of the final cessation of menstruation. The ovaries are then occasionally found of an intense red colour, from the parenchyma, as well as the follicular walls, being deeply loaded with blood. The most marked instances of this I have observed in connection with car- diac disease, and associated with congestion of other organs. Inflammation of the Ovary. — Ovaritis. — Oophoritis. — Our knowledge of the patholo- gical changes which the ovary undergoes as the result of inflammation, is chiefly derived from examination of the bodies of women who have died of acute puerperal metro-peri- tonitis. But unquestionably inflammation both in the acute and chronic form may affect the substance of the ovary, independently of the puerperal or pregnant states, and cause various degenerations of the tissues of that organ, as evidenced by those serous, fibrinous, and puriform deposits, or general softening of the ovarian parenchyma, which are occa- sionally found after death. It is probable also, from symptoms displayed during life, that inflammation, especially in a chronic form, not unfrequently attacks the ovary and termi- nates in resolution, or in those milder results of inflammation which consist in temporary induration or enlargement of the organ, unac- companied by serious disintegration of its tissues. It must, however, be observed with regard to the evidences of inflammation of the ovary either in the acute or chronic form, which are supposed to be afforded during life, consisting in pain and tenderness referred to the seat of that organ, or in obvious enlargements of the ovarv, as discoverable by various modes of internal or external tactile examination, and conjoined with more or less constitutional dis- turbance, that these signs may and do often in the non-puerperal state, accompany the natural process of ovulation, and that such symptoms, recurring with each menstrual pe- riod, may affect a woman at intervals in a greater or less degree during the whole of that period of life in which she is capable of child- bearing. But in the present state of our knowledge of ovarian processes it is perhaps not possible to determine how much of these symptoms may be regarded as evidence of a natural, and how much of a morbid change in the part ; for although in many women the process of ovulation is continually performed without consciousness of local suffering, yet in a great number of instances the act is accompanied by much pain, and there can be no question that the cause of much of this suffering is to be looked for in the changes which the tissues of the ovary undergo in the act of expelling the ova. How closely this process in its more ob- vious conditions is allied to inflammation has been already shown. A high degree of vas- cularity of the part, with increased exudation of fluid, and consequent enlargement and ten- sion of the entire organ terminating in spon- taneous laceration of its coats by a process very similar to ulceration, and often accom- panied or preceded by a more or less consi- derable escape of blood : these together form a combination or series of processes closely allied in their nature to inflammation, and frequently evidenced externally by signs usually regarded as characteristic of inflammatory action. Nor is it yet known how far these sym- ptoms, which have generally been assumed to indicate ovarian inflammation, especially in a chronic form, may be merely the external evi- dences, not of natural, but of aberrant or dis- appointed ovulation. For just as an abscess is painful generally in exact proportion to the unyielding nature or tension of the parts by which it is surrounded, so it is probable that when the follicle or the entire ovary becomes tense from the effusions which have been shown to have taken place ordinarily within it, and this tension is not relieved because rupture does not occur at the proper time, so that ovulation is disappointed or is aberrant, the symptoms which might be expected to ac- company such an interrupted process would be those which are usually set down as indi- cating inflammation in a part. This matter appears hitherto to have been hardly thought of, and yet it is probable that to abortive or interrupted ovulation may be referred the commencement of many of those morbid conditions of the ovary which are not either malignant or the direct results of inflammatory action. Probably many of the cystic diseases of the ovary originate in this way. Of disappointed ovulation, as it may be observed in animals, instances have been given at page .568. Here the follicles, although apparently preparing for rupture, were arrested in their progress from some un- explained cause ; and although it may be con- jectured that such follicles might, under an increase of stimulus, accomplish their final purpose, as Coste has supposed in reference to the instance just quoted, yet it has been shown by the researches of Barry that mul- titudes of ovisacs perish without accomplish- OVARY — (ABNORMAL Ax ATOM v). ing that purpose at all, and it is probable that these, in preference to other and more healthy follicles, become the seat of subsequent mor- bid changes. For it must be remembered that the cir- cumstances under which the male and female generative elements escape from the place of their original formation are essentially dif- ferent. The male secreting organ, the testis, is provided with an excretory duct for the escape of the fertilising fluid ; but the female gland is a shut sac. To the normal escape of its products many barriers are opposed, and it has already been shown by what com- plicated machinery the shedding of the female product is effected. But it is impossible to regard this complex process without perceiv- ing how easily a failure in any of those steps may defeat the final object for which that process is set on foot. The thickness of the walls of the follicle, the density of the ova- rian coverings, or of the parenchyma of the ovary, if the follicle should fail to reach the sur- face ; the chance of the ovum perishing before it quits the ovisac, and so the stimulus to the healthy development of the latter being lost ; the chance of an excessive accumulation of liquor folliculi or of blood within the follicle, causing damage to the ovum, and replacing a natuial by a morbid amount of exudation. In these and other possible interruptions to the natural completion of ovulation we may discover the elements of many future morbid changes. And although it would require a long continued and deep research into the aberrant functions of the ovary to determine the true order and sequence of many of these morbid processes, yet it is impossible to carry anatomical investigation into the structure of the morbid ovary, especially under incipient forms of disease, to any extent without many fragmental observations occurring suggestive of the idea that the ovary, like any other gland, may have its natural functions'impeded, and that many of the organic changes which are observed in this part may owe their origin to such interrupted processes. Some of the observations which have led me to the adop- tion of these views have been already given, and some others will be detailed as suggestive of a better basis for the study of "ovarian pathology than has hitherto been employ ed ; for of all the organs of the body the ovary is perhaps that whose pathological conditions have been regarded with the smallest amount of reference to its natural or deranged func- tions. From these considerations, then, I have been led to the conclusion that certain conditions of the ovary, which, from their concomitant symptoms during life have been deemed in- flammatory, are not necessarily associated with inflammation ; that it is probable, first, that the natural process of ovulation is often ac- companied by symptoms very similar to those of inflammation ; and secondly, that the pro- cess of ovulation is occasionally disappointed or interrupted, and that the follicles, whose Sup p. §77 natural development has been interrupted, may, like the hydatiform placenta, become the seat of a low form of nutrition, terminating in effusion and collection of various dropsical fluids. With regard to the anatomical evidences of inflammation of the ovary as furnished by post-mortem examination, they are chiefly the following, viz. : general redness or hyperaemia of the ovarian parenchyma, or of the walls of the follicles ; swelling of the ovary to the ex- tent of increasing the organ to three or four times its natural size, producing a round, oval, or flattened form of the ovary ; a general tension or hardness of the organ in the early stages of inflammation, and subsequently softening, con- sequent on degeneration of the tissues and their infiltration by serous or puriforin effu- sions ; and lastly, but rarely, gangrene of the ovary. Of these morbid changes the only one which appears to require a more particular account is Suppuration of the ovary. Pus may be found in a circumscribed cavity within an en- larged and highly vascular ovary, portions of whose structure may still retain its natural condition. Or the entire ovary may be con- verted into a bag of pus, the natural tissues being entirely destroyed, and the fluid bounded only by the ovarian tunics. In such cases the abscess " appears to rise from suppuration in the substance of the viscus, similar in every respect to phlegmonous abscess in any part of the body, and not connected with any cyst, or change, or addition of structure, the product of morbid growth."* These abs- cesses, which are sometimes of enormous size, may burst into the general sac of the peri- toneum, or, after forming adhesions with sur- rounding parts, may discharge their contents externally through the abdominal walls, or into the Fallopian tube, uterus, vagina, blad- der, rectum, or other part of the intestine. Portal mentions cases of ovarian abscess as large as an infant's head, and Dr. Taylor f of Philadelphia has recorded an instance in which the ovary contained twenty pints of pus. It is highly probable that these and even still larger collections of pus, which have been found in the ovary, were, as Mme Boivin has suggested, originally cases of encysted ovarian dropsy, but inflammation and suppuration having been set up in the walls of the cyst, the original contents have been gradually in- termixed with pus, until the whole fluid has appeared to be of that nature. Probably of this kind also was the case recorded by VaterJ, in which the ovary was as large as the human head, and " contained pus distributed into several capsules." This, therefore, was a multilocular abscess. Except in connection with acute metro- peritonitis, suppuration of the ovary may be considered as comparatively rare. Dr. * Seymour's Illustrations of some of the principal Diseases of the Ovaria, p. 40. t North Amer. Med. & Surg. Journ. 1826. i Haller, Disp. Med. P P 578 UTERUS AND ITS APPENDAGES. Hooper* " met with only two instances of abscess" of this organ. "The one was the size of a child's head at hirth, the other not larger than an orange. There was nothing in these different from common abscesses ; the whole of the internal substance of the ovaries was gone, and the walls were formed of a thick and mther ligamentous cyst, covered by peritoneum." Suppuration occurs also occa- sionally in those cysts of the ovary which con- tain hair and teeth, together with other im- perfectly formed products. To the same class of suppurative diseases should also probably be referred that singular morbid condition of the part in which the entire ovary is reduced to the state of a diffluent pulp, of a yellow or brownish-green colour, of the consistence, and having somewhat the appearance of very soft putty, immiscible with water, and retaining sufficient tenacity to preserve its semifluid character, and yet not having firmness enough to admit of the part being preserved as a pre- paration. Of this morbid condition of the ovary, which, however, may possibly be can- cerous, I met with a striking example in a case of sudden death occurring in the seventh month of pregnancy. Both ovaries were of the size and form of a bullock's kidney, their natural structure was entirely destroyed, and was replaced by the soft substance just de- scribed. The circumstance that both ovaries were thus affected renders it evident that the disease could not have existed in any great degree at the time of impregnation, or that it certainly must have been then limited to one organ. From the comparatively scanty materials extant relating to ovarian abscess it may be concluded, that suppuration may either com- mence at separate parts of the parenchyma, forming small collections of matter, which gradually coalesce, or it may be set up through- out the whole of the stroma at once. In these cases the parenchyma of the ovary is gradually consumed, and the organ is converted into a purulent cyst.f Whilst in other cases the Graafian follicle appears to be the seat of the suppurative action, which may either com- mence originally in the walls of one or more follicles constituting circumscribed abscesses of moderate size, or the suppurative stage of inflammation may be established in the walls of a follicle already considerably enlarged, and thus an ordinary ovarian cyst, with simple transparent contents, may be gradually con- verted into an abscess of enormous magnitude. Cysts. — A complete anatomical description of the numerous forms of cystic disease which affect the ovary would occupy a far larger space than the limits of this article will per- mit. On this account the more important varieties only can be noticed. These are chiefly Simple cysts, Compound cysts, Hy- datid cysts, Demoid cysts, or those contain- * The Morbid Anatomy of the Human Uterus and its Appendages, p. 3. t Rokitansky, Path. Anat. vol. ii. p. 331. Syd. Soc. edit. ing fat, hair, teeth, and bones, and Colloid cysts. Simple Cysts. — The simple, barren, or uni- locular ovarian cysts are composed, as their name implies, of a single sac, which, accord- ing to its size, occupies the interior of the ovary, whilst the rest of the organ retains its normal condition ; or else the cyst, by en- larging, presses aside and distends the paren- chyma and tunics of the ovary, which thus form a common boundary to the sac, or the cyst, having originated in one extremity of the ovary, grows at the expense of that portion of the organ, whilst the rest, retaining its natural structure, becomes by degrees a mere appendage of the sac, and may be seen pro- jecting in the form of a small button-like pro- minence from its outer surface. These cysts vary in size from that of a pea to the bulk of the adult head ; they rarely, however, attain the latter dimensions without becoming proliferous or multilocular, and they appear never to acquire as single cysts the enormous bulk which the compound cysts not unfrequently exhibit. This more moderate size of the single cyst is less frequently pro- ductive of those adhesions with surrounding parts which the pressure of the larger com- pound cysts so commonly occasions. Hence the precise locality of the single cyst, and its origin in the substance of the ovary, can generally be determined without difficulty. The distended sac is found hanging as an ap- pendage to the ovarian ligament, whilst the Fallopian tube is often seen partly spread out over its surface, one of the fimbriae being always closely adherent to the sac, and con- ducting the observer infallibly to any portion of the original ovarian structure which may have remained yet unchanged. The coats of these cysts vary much in density and thickness. Those of the single kind are more uniform throughout ; they are generally thickest towards the base or seat of their vas- cular supply. Here they vary in thickness from 2'" to 12'", but become much thinner in other parts, so as at times to be nearly trans- parent. The outer coat always consists of peritoneum, which is smooth and shining upon its surface, except when adhesions have been formed with surrounding parts, or when fatal peritonitis has occurred, as from bursting of the sac. The condition of this coat has been already described under the head of morbid states of the ovarian tunics. The variations in its thickness are not generally so consider- able as materially to affect the bulk of the sac. The middle or intermediate coat is that ge- nerally upon which the greater or less density of the cyst wall depends. This coat is usually of a brownish-yellow colour, and firm fleshy texture. It is with difficulty split into a number of rough -surfaced laminae, exhibiting to the naked eye a coarse fibrous arrangement of their constituent parts, which, under the microscope, are seen to consist of inelastic fibrous tissue, mingled with granules, and undeveloped fibre cells in varying proportions. OVARY — (ABNORMAL ANATOMY). To this coat, which appears to retain or in- crease its thickness by a perpetual new for- mation of fibrous tissue, is due that support and resistance to the pressure of the in- creasing contents of the sac, which prevents the more frequent rupture of these cysts. And it is probable that when the latter phenome- non occurs, without the formation of previous adhesions, followed by ulceration, the lacera- tion is due to the gradual attenuation of the middle wall of the sac. Occasionally portions of these walls are found to be of nearly cartilaginous hardness, so that they can with difficulty be broken up into fragments for minute examination. Such portions are seen under the microscope to be composed almost entirely of close-lying fibres of white fibrous tissue, with scarcely a trace of the embnonic fibres and granules, which are found abundantly in the walls of the softer cysts, and of the normal ovisac. Other por- tions of these cyst walls, still more dense, present to the naked eye, as well as under the microscope, all the characters of the simpler forms of cartilage ; whilst in the walls of other cysts again are found patches of ossific matter, in which the earthy elements of bone are aggregated together, (calcification) but without the definite arrangement characteris- tic of true osseous structures. Upon and in the substance of this middle coat ramify numerous arteries and veins, some- times of considerable magnitude. These dis- tribute their minute branches upon the inner surface of the cyst, where they occasionally present a peculiar straight or rectangular ar- rangement. Doubtless these vessels are the carriers of those enormous collections of fluids which accumulate within the cysts, and upon their arrangement, as well as upon the nature of the epithelial lining of the sac, depends probably the character of the fluids secreted or effused. Most variable is the condition of the lining membrane which bounds the inner surface of the cyst. In the smaller cysts it is often com- posed of one or more layers of simple flat- tened epithelial cells ; the remains, perhaps, of themembranagranulosa. This surface may be free, or to it may adhere fragments of blood clot, degenerating or undergoing fibrillation, by which the sac, when small, is partly filled. This lining of epithelial cells is often seen in a state of fatty degeneration*, and similar cells are found abundantly scattered among the contents of the sac. In the larger and older cysts the membrane lining the sac is nearly as smooth as that which covers it externally. In these the lining membrane often exhibits but little vascularity, and shows small traces of an epithelial cover- ing in its smoother parts, where it is usually so intimately adherent to the middle walls, as to be separable from the latter only with diffi- culty. Fragments so obtained "are easily split up, ancf are seen to be composed of deve- loped fibres of connective tissue, intermixed * Wedl, Patholog. Histol. p. 461. Syd. Soc. 579 with fine granules and a few embryonic fibres. After the simple cyst has arrived at a cer- tain period of its growth, and generally when it equals the size of a large orange, it begins to exhibit upon its inner surface patches, more or less extensive, of rough projections, gra- nulations, or vesicles, which will be described more fully under another section. Multiple Cyits. — I have employed this term to designate a variety of the single cyst which might be confounded with the compound or proliferous kind, and which consists merely in an aggregation of two or more simple cysts that have been contemporaneous in their growth. The distinction between a mere ag- gregation of simple cysts and the growth of a compound one has been carefully drawn by "Rokitansky*, and has been also illustrated by Paget.f If such cysts are observed at an early period of their growth, they may be seen to occupy different portions of the ovary in which they arise independently of each other, and having distinct portions of ovarian stroma interposed between each. They have at first a round or oval form, but " as they all enlarge together, and sometimes by the wasting of their partition walls come into communication, they are flattened by reciprocal pressure, and " may at length look like a single many-chambered cyst, having its one proper wall formed by the extended fibrous covering of the ovary. Many multilocuhir cysts, as they are named, are only groups of close-packed single cysts ; though when examined in late periods of their growth, and especially when one of the group of cysts enlarges much more than the rest, it may be difficult to distinguish them from some of the proliferous cysts. Figs. 392. and 393. serve to illustrate the simple and the multiple cyst respectively. fig. 392. has been described at p. 575, where this example is given as an instance of hyper- trophy of a Graafian follicle in an early stage, forming a simple or unilocular cyst, still hardly contained within the substance of the ovary. It will be seen that at one part of this preparation the wall of the cyst has become blended with the general investments of the ovary ; and it will be easily understood how, bv the gradual enlargement of the cyst in this direction, where there will be the least amount of resistance to its growth, the sac may at length become so greatly expanded that the remaining healthy portion of the ovary will appear only as an appendage to it, or may become by pressure and extension altogether obliterated. Fig. 393., taken from Dr.Hooper's collection £, offers a good example of the mul- tiple cyst. It is composed of a mere aggre- gation of simple or unilocular cysts, which, by coincident enlargement, have come at length to fill the entire ovary, causing considerable increase in bulk of that organ. From the right ovary (a) a portion has been removed * Loc. cit. p. 332. f Lectures on Surgical Pathol. Vol. ii. p. 56. J Morbid Anatomv of the Huuian Uteru*. 1> p 2 580 UTERUS AND ITS APPENDAGES. exhibiting a section of several simple cysts of nearly equal size ; whilst the left ovary (6) shows a similar alteration of texture, the organ being still unopened, and exhibiting numerous small sacculi which have here begun to project above the surface. Fiff. 393. a, right ovary, exhibiting numerous unilocular cysts, consisting of enlarged Graafian vesicles; b "left ovary similarly affected, but unopened ; c, uterus. (After Hooper.} Multilocular, Compound, or Proliferous Cysts. — In these a second, or, it may be, a third, order of smaller cysts are developed, within or upon the walls of a larger or parent sac. From these walls the secondary cysts, at a comparatively early period of their growth, are seen projecting inwardly in hemispherical form, arranged along the parietes of the sac, from which they commonly spring by broad bases. These secondary cysts are invariably and permanently attached to and continuous with the walls of the superior cyst. They are covered by a continuation of the same membrane which lines the principal sac, and which is reflected over them in the same man- ner that the heart is invested by the reflected pericardium, or the testis by the tunica va- ginalis.* Fig. 394. The left ovary distended into one large cyst, into the interior of which project numerous smaller cysts of a secondary order. To the right of the figure is the uterus. (Ad Nat.) * Hodgldn, Lectures on Serous and Mucous Membranes. Lect. viii. OVARY — (ABNORMAL ANATOMY). 581 The growth of these secondary cysts with broad bases, of which a good example is ex- hibited in Jig. 39-t., is often very irregular, so that one or more of them enlarging with greater rapidity than the rest, encroach upon the cavity of the containing cyst, and fill it more or less completely. This rapid enlarge- ment of the secondary cysts also occasionally causes rupture of their walls and the escape of their contained fluids into the parent cyst, followed by the unrepressed growth of the secondary or tertiary cysts which arise from its surface. After the appearance of a tertiary order of cyst within the secondary ones, their growth occasions so much disturbance of the even outlines of the walls in which they originate, that it is often difficult to trace the order and manner of enlargement of the different series. Nevertheless, with care, these may be often made out even in the complex forms, of which Jig. 395. furnishes an example. Here is re- presented a small portion only of an enor- mously enlarged ovary, consisting of a primary or principal sac, the greater part of which ha's been cut away, so as to leave a part of its walls visible at a, a, a , and of a more solid basis which was made up of numerous secondary Fig. 395. Compound or proliferus ovarian cyst. (Ad a, a, a, divided walls of the principal single cyst ; b, small simple cyst ; c, c, two masses of compound secondary cysts, containing many of a tertiarv order. and tertiary cysts. Both of these orders may be traced in this example. At «, a, a are seen the divided walls of the original parent cyst, whilst springing from these walls at b is a single secondary cyst, and at c, c are two groups of similar cysts aggregated in masses. The lat- ter are, however, examples of compound se- condary cysts, for in the interior of each is contained a series of a tertiary order, which are so numerous as to fill completely the secondary sacculi. By Lebert it is deemed to be still an open question whether these cysts, which apparently spring from the in- terior of the main sac, as represented in Jigs. 394. and 395., are altogether new formations, or whether they were not originally in part developed, and by force of pressure, arising from contiguity of situation, have penetrated and at length grown within the principal cyst, into the interior of which, in this view, therefore, they would form a species of hernia. Dr. Hodgkin *, whose elaborate descrip- tions of ovarian cysts has made known all the principal varieties of form which they assume, distinguishes from the broad-based cysts, al- ready noticed, those which arise by narrow or slender peduncles. These sometimes grow from the walls of the principal cyst, and, in- deed, in almost all cases which I have exa- mined, after the sac has attained a certain size, patches of these pedunculated sacculi may be observed scattered over the interior in various places, but they are more constantly observed growing from the interior of the secondary cyst. These little sacculi appear at first in scattered patches, under the form of little round grains, thickly covering the lining mem- brane which they raise above them, and so closely set that two or three hundred mav sometimes be counted in the space of a square inch. When these elongate, mutual pressure causes them to assume a filamentous condition ; but when greater freedom of growth is enjoyed, their extremities commonly dilate into little pouches, or buds of another order sprout from the sides and extremities of the original growths, and convert them into a multitude of little dendritic processes which roughen the inner surface of the larger cysts, or fill more or less completely the cavities of the smaller ones. If a section be made of these dendritic processes, they are seen usually to be solid at their base, the white fibrous tissue of the parent cyst wall, from which they spring, being easily traced into their stems and branches. But at their extremities they become dilated into little pouches filled with fluid, similar to the little pediculated cysts, with which they are abundantly intermixed. These little cysts and processes are covered by epithelium, and it is probable that they are the active agents in the elimination of the various fluids by which the ovarian cysts, of whatever order, are com- monly filled. These minute processes and vesicles, so abundantly found on the walls of endogenous cysts, are represented in j€g. 396., which exhibits a portion of a proliferous cyst of the natural size, covered by them on its inner surface. * Loc. citat. and Med. Chir. Trans. Vol. xv. pt. ii. p p 3 582 UTERUS AND ITS APPENDAGES. Fig. 396. Part of the thick laminated wall of an ovarian cyst, covered on its inner surface with pyriform vesicles. (After Faget.} The Contents of Ovarian Cysts, — No cystic formations in any part of the body present such -a variety of contents as those which are found in the ovary. These vary in every de- gree of consistence, from the thinnest fluids to the hardest substances, such as teeth and bones. They may be subdivided according to their densities and different degrees of organi- sation. And first may be considered : — The Fluid Contents of Cysts.— The thinnest fluids are usually obtained from unilocular cysts, which have not been previously tapped. The fluid so procured is commonly of a pale straw colour, and resembles in general charac- ter the ordinary fluid of ascites. It is to these cases that the term " encysted ovarian dropsy " is most commonly applied. The contents of multilocular cysts are often less fluent, presenting every variety of consistence from a thin gelatinous fluid to one of the density of white of egg, of honey, of thin size, or of soft glue. In the latter cases the tenacity of the fluid is often so great that it may be drawn out into long strings, and it is only in this way that it can be extracted through the canula. All these varieties, which commonly retain more or less transparency, may be found enclosed in different cysts within one common investment. In other cases the contents, while retaining their fluidity, are rendered turbid or are thick- ened by the admixture of pus or of blood in various degrees. Thus are produced the yellow and green hues as well as the red, reddish-brown, and dark coffee-ground colours which these fluids often present; the turbid yellow and green colours being generally caused by the presence of pus, the bright red by the admixture of recent blood, and the dark brown or coffee-ground hue sometimes by the addition of blood which has been effused long enough to have undergone putre- faction, although the brown colour is not al- ways due to this cause. Scales of cholesterine are also found intermixed with those fluids, and in the smaller cysts especially, as already stated, recent blood or the blood clot under- going fibrillation, or breaking down by putre- faction, may be frequently noticed. The repeated withdrawal of the contents of ovarian cysts affords the opportunity of ob- serving that the fluid contained in the same sac often undergoes a material change in its composition. Thus, that which is obtained by a first tapping is often of the thin straw-co- loured variety, whilst that which results from subsequent operations has more frequently the turbid muddy or coffee-ground character last described* This can be explained in two ways : the first, by observing that in multilocular cases there is sometimes a natural communication between the walls of the containing and the contained cysts, or an artificial communication may be established by spontaneous rupture, or "by the trocar penetrating through two cysts, and thus the smaller will act as tribu- taries to the larger sac, and pour their varied contents into it; or secondly, inflammation or ulceration may be set up in the walls of a cyst which has been punctured, or the intro- duction of air, or of blood flowing into the cyst from vessels wounded during the opera- tion may so modify the contents as to account for those successive alterations in the fluid which are very commonly observed. In the case of cysts containing pus, rough patches, apparently of ulceration, have been observed upon their internal walls. Quantity of Fluids and Rate of Effusion. — The structure and situation of the ovary per- mit this organ to suffer a degree of distension which is rarely or never equalled in other parts. Probably the only limit to the increase in size of the morbid ovary, after it has risen out of the pelvis into the abdomen, is occa- sioned by the pressure which the spine, dia- phragm^ and abdominal walls exercise upon the cyst $ for the parietes of an ovarian cyst appear in most cases to possess an unlimited capability of multiplying the fibrous element of which they are principally composed, whilst the power of rapidly replacing the fluid after their contents have been drawn off', proves both the unrestricted capability of secretion inherent in the cyst walls, and at the same time the influence which pressure exerts in keeping that secretion for a time within cer- tain limits. Numerous examples might be quoted in illustration of the immense power of growth and secretion of fluid possessed by ovarian cysts. ImhofF* records a case in which the right ovary contained 42 Ibs. of fluid. Duretf met with 50 pints of water in * Acta Helvetica, vol. i., App. p. 1. f Mem. de 1'Acad. de Chir. t. ii. p. 457. OVARY — (ABNORMAL ANATOMY). a single ovarian cyst. And in the London Medical and Physical Journal (Aug. 1815) the particulars of a case are given in which the right ovary weighed nearly 52 Ibs. But these are moderate examples compared with some of still larger growth. Camper* relates a case in which about 80 Ibs. of serum were contained in the left ovary ; and Douglas also one in which the left ovary held 70 Ibs., besides a considerable collection of fluid in the pleura and pericardium.^ These enormous collections of fluid are ge- nerally limited to the ovary of one side, though both organs may be coincidently affected, as in the example given by W. E. L. Miiller J, who found in the body of a woman, aged 36, in the two ovaries together 140 Ibs. of fluid. In what proportion either or both of the ova- ries are affected by ovarian dropsy may be seen by reference to the tables of Safford Lee and Chereau. The former shows the right ovary affected 50 times, the left 35, and both together 8 times. The latter gives 109 ex- amples of the right, 78 of the left, and 28 of both sides. Notwithstanding the large amount of fluid which may collect within the distended ovary as shown in the foregoing examples, these yet serve to give but a feeble notion of the enor- mous quantities which may be effused from the walls of an ovarian cyst in the course of a lifetime, or even of a few years, when the contents are removed from time to time, and are allowed to re-accumulate. Pagenstecher$ removed, in 35 operations, 1132 Ibs. of fluid, without reckoning what escaped by allowing the canula to remain. Dr. Mead's patient was tapped 67 times in five and a half years, and lost 1920 pints. Ford jj punctured the ovary 49 times, and removed in all 2786 pints 583 of fluid. Heidrich * in eight years punctured 299 times, and removed 328*9 Berlin quarts (Berl. Maass), equal to 9867 med. pounds, the death of the woman occurring at the age of 43. And in the celebrated case of Mr. Martineau, of Norwich, in the course of twenty-five years the patient lost by tapping, in 80 operations, 6631 pints, equal to 13 hogsheads of fluid. Composition of the Fluids contained in Ovarian Cysts. — Although these fluids usually coagu- late freely in a greater or less degree on the addition of heat or nitric acid, the proportion of free ajbumen which they contain is usually considerably less than is found in the serum of blood; they contain, however, a larger quantity in combination with soda than is found in that fluid. According to the analysis of Dr. Owen Rees, who has examined several specimens of ovarian fluids, their chief characteristics are, a considerable excess of water and of extrac- tives, and a deficiency of albumen as compared with the serum of blood. To the presence of a large quantity of extractives, particularly the albumen combined with soda, Dr. Rees attri- butes that peculiar tenacious mucoid character which these fluids so commonly possess. This is always in relation to the nature of the solid ingredients, and is quite independent of any peculiar proportions of water, to which at first it might be supposed to be due. Again, the alkaline salts obtained from ovarian fluids dif- fer from those of blood in not containing any phosphate which can be recognised even as a trace, unless experiments be made upon large quantities for the express purpose of detect- ing that substance. The following table f, by Dr. O. Rees, gives the results of the analysis of four fluids drawn from secondary cysts of an ovarian tumour, compared with art analysis of the serum of blood. No. 1. No. 2. No. 3. No. 4. Clear straw- Clear, light straw- coloured Alkaline. Dark- coloured muddy neutral. Approaching in character to white of Alkalme, coloured, containing flakes or a pearly scaly- loo'king " Analysis of the Serum of the Blood for comparison. substance. Sp. G. 1017. Sp.G.1017. Water ----- 190-9 190-70 195-2 187-7 181-2 Albumen with traces of fatty matter • - 41 4-25 1-8 7-6 16-5 Albumen existing in solution as Albu^ minate of Soda - } " 3-G2 1-1 0-4 Alkaline Chloride, and Sulphate, with Carbonate of Soda, from decomposed Albuminate - t- 0'8 0-78 1-2 4-0 1-GJ>| Extractive, soluble in water and alcohol 0-4 0-45 0-5 0-5 0-3 Chloride of Sodium with Carbonate, from \ decomposed lactate of Alcoholic Ex- 0-1 0-20 0-2 0-2 tract - - - - - 200 200 200 200 200 * Sammlung, bd. xvi. s. 562. t Those who are curious in these cases will find instances referred to by Meissner (Die Frauenzim- merkrankheiten, Band ii.), in which a single ovary is said to have weighed 100, 120, and 150 Ibs. re- spectively. % B. v. Siebold's Sammlung, 1812, iii. Bd. § V. Siebold's Journ. fur Geburtsh,b.vii. St. i.s. 93. || Medical Communications, vol. ii. 1790. * Dissert, sistens Casuua Memorabilem, Berol. 1825. f From a valuable paper on Tumours of the Ovary, by Dr. Bright, in the Guy's Hospital Reports, vol. iii. p. 204. J The whole of the Alkaline Salts are estimated together in the analysis of serum as indicated by the line. p P 4 584 UTERUS AND ITS APPENDAGES. So far, therefore, as these analyses may be taken to represent the ordinary composition of the more fluid contents of ovarian cysts, it may be concluded that the action performed in these cases by the walls of the cyst is the separation from the blood chiefly of the watery and saline ingredients, with the exception of alkaline phosphates, whilst the albumen is only in part removed, and none of the fibrine. Examined by the microscope, the more fluid contents of ovarian cysts frequently ex- hibit flocculi, composed of patches of epi- thelium, more or less united together by gra- nular matter. When gelatiniform they often contain faint oval corpuscles, or a few primi- tive corpuscles. Occasionally an opalescent or opaque creamy appearance is communicated to the jelly by the formation of pus corpuscles or minute granules, and sometimes the con- tents are wholly filamentous, and mixed with granular cells and other products of inflam- mation. This jelly-like matter, when consist- ent, presents all the characters of coagulated liquor sanguinis, which has not yet passed into organisation. Acetic acid develops in it, or causes to be precipitated a white membrane having all the characters of fibrous tissue. Frequently granules, cells, and filaments may be observed in it in various stages, as is the case with recent exudations from the serous membranes, or in other simple forms of hya- line blastema.* Hydatids contained in Ovarian Cysts. — A very perfect example of this rare affection of the ovary (originally in the possession of Dr. Hooper) is contained in the Pathological Museum of King's College. It is the largest specimen of ovarian disease in that collection, and consists of an immense aggregation of compound thin-walled cysts, of the second and third order, many of the latter being stuffed full of hydatids. Several of these have fallen out of the cysts, and lie loosely at the bottom of the glass. They are of the form and average size of pigeons' eggs, and possess the usual characteristics of Acephalocysts. (Barren echinococcus vesicles?) Compara- tively few cases of this form of ovarian disease are on record. The solid Contents of Ovarian Cysts. — These consist of fatty matter, hair, teeth, and bones. Cysts containing such materials are termed dermoid cysts. They rarely grow with the rapidity, or attain the enormous bulk com- monly observed in those with fluid or hydatid contents. That such cysts may, however, sometimes equal in size those of a more sim- ple character, is shown by a remarkable ex- ample described by Blumenbach. j- A girl aged 17 had a swelling of the left ovary, which after 21 years' growth measured four ells in circumference, and reached below the knees. Death occurred at the age of 38, when the sac of the ovary alone weighed 14lbs., and contained also 40 Ibs. of a thick, fatty, honey- like substance, mixed with short and long * Dr. J. II. Bennett on Encysted Tumours of the Ovary and Pelvis, Edin. Med. and Surg. Journ. No. 1G7. t Medicin. Biblioth. bd. i. s. 152. hairs, some two feet in length, and matted together in locks. Besides these the sac con- tained several irregular portions of bone, some of large size. In one of these were fixed six molars and one incisor tooth, completely formed. The inner surface of the sac was beset with short hairs. The composition of these cysts, and espe- cially of their lining membrane, will in a great measure account for the differences which are observable in their progress and mode of growth. The dropsical cysts are closely allied in their nature to serous membranes, and, like these in a morbid condition, they possess the power of separating and collecting into their cavities the thinner constituents of the blood. And as the only apparent limit to this process is the resistance offered by the walls of the sac, and the parts external to them, so the distensibility of these, and the capacity of the walls of the cyst to meet the increasing pres- sure by a correlative hypertrophy of its tis- sues, will determine the form, size, and general condition of the tumour. But the non-malig- nant cysts, whose contents are of a more solid nature, and possess a higher organisation, are tegumentary in their character. Their con- tents are chiefly tegumental products, which, once formed, have attained the limit of their growth. Such cysts, therefore, are more sta- tionary in their character ; or if occasionally they approach in bulk the watery cysts, as in the example just quoted, this arises mainly from the addition of a fluid secretion, and the necessity for circumscribing it by hyper- trophy of the walls. But more often the cysts with solid contents, if they do not re- main passive, contract adhesions with sur- rounding viscera, and by the aid of fistulous openings discharge their harder parts, such as bones, through the nearest natural orifice. The tegumentary character of these cysts has been clearly shown by Cruveilhier*, Kohl- rauschf, Lebert j, and Paget.§ "Upon their inner surface is produced a growth of skin, with its layer of cutis, subcutaneous fat, epi- dermis, and all the minute appended organs of the proper hairy integument of the body ; " whence the term " dermoid cysts." It is pos- sible that at the commencement of their for- mation such cysts may have a general tegu- mentary lining, a part or the whole of which may afterwards become obliterated. For in the condition in which they generally come under our notice, the tegumentary structure is con- fined to patches of the lining membrane, while in many the hair is found entirely detached and lying in the form of a loose ball in the centre of a smooth-walled sac. Sebaceous and Sudoriparous Glands have been shown by Kohlrausch and Heschl to be present in these cysts, where they have the same general arrangement as in the skin Ofc.397.c). Fatty Matter. — This occurs under two forms : first, as a loose granular fatty sub- * Anat. Pathol. torn. i. livr. xviii. t Muller's Archiv. 1843, p. 365. j Traite d'Anat. Pathol. § Lectures, vol. ii. p. 83. OVARY — (ABNORMAL ANATOMY). stance, of the consistence and aspect of lard or butter, in the midst of which are imbedded those coils of loose hair with which it is usually associated (/g. 397. d). This fatty material is of a white or yellowish hue, and is commonly inodorous, but sometimes it ex- hales an intolerably fetid odour, especially in those cases where air has been admitted into the sac, and partial decomposition has taken place, or where foetid pus has been formed within the cyst. The second condition under which fat is found is that of masses £ — V in thickness, lying beneath the general lining of the sac, which is protruded before them, caus- ing irregular elevations into the interior of the cyst (Jig. 397. a). These present the ordinary character of adipose tissue, but pos- sess a smaller proportion than usual of the cellular element. Hair is found in ovarian cysts also under two forms, either still attached to the walls or lying in loose tangled coils in the centre of the cavity. Those attached to the walls are seen to spring from follicles, which may be scattered evenly over the cyst wall, in which case the hairs are usually short, or they may arise from a group of hair follicles, closely set, and imbedded in a substance clearly possess- ing the characters of ordinary skin. In the latter case the portions of integument from which they spring are generally elevated upon a mass of subcutaneous fat, as just described, and the hairs, which are well nourished and long, form at their free ends a tangled coil, intermingled with the loose fat already men- tioned (fig. 397.). In these cases the hair often attains to a considerable length ; it is fine and smooth, and resembles the long hair of the back of the head, exceeding sometimes in length two feet. The colour of the hair is usually red, dark brown, or black ; it bears no resemblance to the hair of the individual in whom it occurs. Thus, in the case of an ovarian cyst occurring in a negress, Andral observed numerous hairs differing essentially from the wroolly hair of the head ; they were soft, smooth, red, or blonde, and some were silverv, like the hair of children of white races. The loose hairs may be easily detached by maceration in turpentine or ether, from the mass of fatty substance in which they are entangled. They are then sometimes seen to be destitute of bulbs. They are usually more crisp and shorter than the attached hairs, ex- cept when the latter occur singly. Teeth are very commonly found associated with hair and fat. These may possess the perfect character of incisor canine or molar teeth, but more frequently the resemblance is only general, and a more accurate examination discovers in them some imperfection of form. The resemblance is sometimes greatest to the deciduous, and sometimes to the permanent set. In the less perfect forms the crowns only are developed, the roots being deficient. But in most cases the intimate texture of the tooth differs in no respect from the ordinary dental structure.* * This is illustrated by Plate 124. of Professor 585 Ovarian teeth are generally found associated with portions of irregular-shaped bone, in which they are often imbedded. They may, however, be attached to the tegumentary lining of the cyst walls, and more rarely they have been found connected to portions of cartilage. Bone. — The bones found within ovarian cysts differ from the ossified portions occa- sionally observed in the cyst in this respect, that, while the latter consist of merely crystalline or amorphous aggregations of earthy matter, the former, although irregular in shape, yet exhibit a true osseous structure, in which may be readily detected the usual arrangement of concentric lamellae, Haversian canals, lacunae and canaliculi. Such bones often bear a sufficient resemblance to frag- ments of jaws and vertebrae to admit of a general comparison with those parts of the skeleton ; but well-shaped and perfect bones are not found, except in cysts of whose nature and origin some doubts at least may be enter- tained. In fig. 397. are represented several of the solid structures commonly found in an ovarian cyst. A long coil of tangled hair, mixed with lardaceous matter, is seen springing from a portion of the cyst wall at a part which is lined by common integument. Here many Fig. 397 Ovarian cyst containing hair, loose fatty mattir, adi- pose tissue, selxiceous glands, and hair follicles. (After Cruveilhier.) hair follicles are observed, some being empty, and others containing short hairs. The parts Owen's " Odontography," exhibiting the microscopic structure of a tooth, from an ovarian cyst in my collection. Five other teeth were contained in this cyst, together with a portion of tegumental struc- ture, subcutaneous fat, bone, and hair. 586 UTERUS AND ITS APPENDAGES. of the cyst covered by integument are seen to be elevated, and it is in the substance of and beneath such elevations that the fatty tissue and bones are usually found imbedded, whilst the teeth have only their roots concealed, their crowns projecting free above the surface. Origin of the Solid Contents of Ovarian Cysts. — It has been conjectured that these are ex- amples of the " foetus in fcetu," or that such remains may be the product of an imperfect ovarian conception. To the former of these suppositions, viz., that such formations result from a cohesion or intus-susception of two or more germs, coincidently impregnated, but of which one only has been perfectly developed, it may be objected that this view fails altoge- ther to explain the circumstance that their formation occurs far more frequently in the ovary than in any other part of the body ; nor does it account for the fact that here a parti- cular class of structures only is developed, whilst in the case of penetration of germs one within the other, various portions of a second foetus, more or less completely formed, and by no means limited to a certain class of struc- tures, are found within the body of the first. The explanation that these are examples of extra-uterine gestation of the ovarian kind is equally unsatisfactory ; for even if the pos- sibility of such a form of gestation be ceded, the fact alone that hair, teeth, and even bones, con- tained in cysts of the kind under consideration, are never found associated with the smallest trace of the membranes peculiar to the ovum, would be fatal to this view. But it can be shown further that such structures are observed in cases where previous impregnation was highly improbable, as in the examples where they were found in conjunction with a perfect hymen*, or where it was impossible, as in the case related by Dr. Baillie of a girl aged 12, whose generative organs were still undeveloped, but one of whose ovaries was filled with hair, teeth, and fatty matter. The two additional circumstances that there is scarcely any portion of the body, such as the subcutaneous tissue, the brain, lung, kid- ney, bladder, and testis, in which similar struc- tures have not been found, and that such formations, though most commonly found in the ovary, are yet not even limited to the fe- male, but have been also observed in the male, completes the catalogue of objections to the argument, in whatever form it may be ad- vanced, that these productions are in any way the offsprings of a spermatic force newly ap- plied to the organisms in which they are formed. The discovery of the fact that a tegumen- tary structure forms the basis out of which many of these products spring, appears to carry us a step further towards comprehending the mode in which some at least of the solid con- tents of ovarian cysts are formed, by exhibiting a connecting link between structures which are elsewhere naturally associated, but it ob- viously fails to satisfy any inquiry as to the * Royal Coll. of Surg. Pathol. Collect, prep. No. 2625. nature or quality of the cell-force which de- termines the development of such products. Fcetus, more or less perfect, contained in the Ovary '(?) — OvarianGcstation. — Graviditas Ova- ria. — Few facts in physiology have been more readily assumed without sufficient examina- tion than that the foetus may be developed within the proper structures of the ovary, and so constitute a form of extra-uterine gestation. So long as it was generally believed that the coitus was the efficient cause of the escape of the ovum from the ovary, and that therefore the act of impregnation preceded that of ovu- lation, there was nothing in such a belief to challenge inquiry as to the probability of the ovum being first impregnated, and still by some mischance detained within the proper struc- ture of the ovary, where it might become de- veloped. But more accurate views of the nature of ovulation and of the true seat of impregnation have led to a stricter inquiry regarding the seat of supposed ovarian gesta- tion. Among the earliest to call in question the accepted views upon this subject was M. Vel- peau, who, previously a believer in ovarian gestation, laid before the Philomathic Society, in 1825, four examples supposed to be of this kind. An expression of doubts as to the pos- sibility of this fact on the part .of many mem- bers led to a more perfect dissection of the parts, in which examination MM. Blainville and Serres were appointed to assist. It was ascertained with certainty that three of the tumours were external to the ovary. With the fourth more difficulty was experienced ; but at length, after isolating the Fallopian tube, which was sound, the detritus of conception was found to occupy a special sac between the peritoneal and proper coat of the ovary, which was entirely distinct. In the following year, M. Geoffrey St. Hilares, in a report upon the subject of Bres- chet's Memoir upon " Interstitial " Extra- Uterine Gestation, expressed his entire disbe- lief in the ovarian variety, and the same views have been advocated by M. Pouchet in his work on Spontaneous Ovulation, and in this Cyclopaedia by Dr. Allen Thomson *, who has there stated the general objections to the doctrine of an ovarian form of gestation. The cases which appear to favour the belief in ovarian gestation may be divided into two classes, viz., those in which the embryo is yet small, and is contained in a sac of mode- rate size, which has not yet contracted adhe- sion with adjacent parts ; and those in which the foetus has attained or approached to full growth, and the sac by which it is surrounded has already contracted adhesions. All the examples that I have had the oppor- tunity of dissecting, or of seeing examined, have been of the latter class, and of these it may at once be said that nothing can be learned from them which could determine, with any degree of accuracy, so difficult a ques- tion as that under consideration. * Vol. ii. p. 456. OVARY — (ABNORMAL ANATOMY). The impediments to such determination which recur again and again in these cases are the following. It is easily ascertained that the sac containing the foetus is external to the cavity of the uterus, and is in some way or other connected with some portion of the in- ternal generative organs ; the Faliopran tube, ovary, and broad ligament of one side being chiefly involved in the tumour, while the cor- responding parts of the other side may remain free. Dissection may serve to unravel these parts to a certain distance, beyond which nothing satisfactory can be determined, on ac- count of the alteration which the tissues have undergone both in form and arrangement ; the hypertrophy of some, and the wasting or blending together of others, rendering further research fruitless for the object in view. To these impediments, other and still greater difficulties are generally superadded. These arise from the death of the foetus, which often takes place several months or even years pre- vious to that of the mother. In the decom- position which follows, the harder parts of the contents of the sac fall asunder, and make their way by fistulous openings into surround- ing viscera, whose surfaces inflame and give rise to serous and fibrinous effusion, while in the few7 hours which succeed to the final de- struction, the parts decompose so rapidly that the post-mortem examination, however early it may be made, often reveals nothing but a semi-putrid mass perfectly unsuited to the de- termination of a difficult anatomical question. For this purpose the cases of the former class can alone suffice. Here the parts are small, and as yet comparatively unchanged, and admitting of dissection. The results of four such examinations have just been given. The following additional examples, which are se- lected from the best recorded cases supposed to be ovarian, will suffice to exhibit the class of evidence upon which a belief in this species of gestation is demanded. Cruveilhier* has described and figured a case in which the entire skeleton of a four months' foetus f is seen hanging external to a sac, occupying the seat of the right ovar}1, in which it is supposed to have been once con- tained. The sac said to be in the inner and lower pan of the ovary is lined by a serous membrane. The two external thirds of the pouch were filled by a spongy areolar yellowish- white mass presenting all the characters of placental tissue. The outer half of the sur- face of the ovary was enveloped in a cartila- ginous shell. No attempt appears to have been made to trace the entire outline of the- ovarian tunics, or to show the condition of the ovarian ligament, or of the Fallopian tube of the same side. The latter, indeed, is not mentioned, but from the representation of the parts it appears to be blended with the cyst, .so that this is quite as likely to have been an example of tubal, or ovario-tubal, as of * Anat. Pathol. livr. xxxvi. pi. vi. f Said in the description to be between one and a half and two months, at which time, however, no such complete skeleton is ever seen. 587 ovarian gestation. The fact also that the cyst had apparently burst and permitted the escape of the foetus when it had attained the size which is seldom exceeded in tubal cases, lends additional probability to this view. Dr. Granville * has published a case, accom- panied by drawings, which he regards as an " undisputed case of purely ovarian foetiferous ovum." The uterus is considerably enlarged, but empty. " The left ovariura presented a large swelling which contained within its own covering an ovum bearing a foetus with all its appendages, of about four months' growth. The ovarian covering burst in three places, and allowed the protrusion of the ovum, whereby the adhesion of the placenta to the inner sur- face of the ovarian envelope was torn asunder," causing death by haemorrhage. A blood-ves- sel, the size of a large crow-quill, which pene- trated the dense portion of the tumour, was ascertained to be a branch of the left sper- matic artery, and a smaller and much shorter vessel, arising from the tumour, was found to communicate with the spermatic veins. " The corresponding Fallopian tube was perfectly sound and loose, particularly at its fimbriated extremity, which had no connection whatever with the embryoferous tumour in its neigh- bourhood. Like its fellow tube, it was psr- vious only from its loose extremity inwards to about half its length. " A placental mass with distinct cotyledonous vesicles connects the child with the inner covering of the ovarian cyst. The secreting or transparent involucra are quite distinct. The cortex ovi is almost wholly absorbed, as it ought to be at such an advanced period. The foetus is perfect." In the expla- nation of the plates mention is made of" frag- ments of the corpus luteum which surrounded the ovum, and was broken to pieces by the enlargement of the foetus. Some of these fragments adhere to the inside of the ovarian coats, others are among the placental cotyle- dons." No account is given of the ligament of the ovary, nor of such a dissection of the parts having been undertaken as would satis- factorily prove that the sac containing the foetus was not a cyst attached to the ovary. But the evidence in favour of ovarian gesta- tion consists chiefly in this, that the foetus- bearing cyst occupied the region of the ovary, and was independent of the Fallopian tube. Nevertheless this case constitutes the nearest approach to the form of gestation which it claims to represent with which I am acquainted. In the same work (Graphic Illustrations f) is contained a description and representation of a second case termed " ovum foecundum in receptaculo ovarico." " Through a transversal aperture in the left ovarium are seen the re- mains of some membranes, three in number at the least, lining a cavity which measures transversely one inch and a quarter, and about an inch vertically." The preparation belonged to Sir C. M. Clarke, who assured Dr. Gran- ville " that a small embryo hung pendulous * Phil. Trans. 1820, and Graphic Illustrations of Abortion, Plates X, A, and B. t P. 27. pi. viii. 588 UTERUS AND ITS APPENDAGES. from the yet visible rudiment of an umbilical cord. That embryo, however, is not now to be seen." The female from whom this was taken was unmarried, but acknowledged her- self to be pregnant. The uterus was larger than in the unimpregnated state. The Fallo- pian tube was not in the least involved in the enlargement. The fimbriae were free. A case which, in the opinion of Dr. Camp- bell *, " in so far as anatomical accuracy is concerned, ought to satisfy those who are still sceptical regarding the reality of ovarian gestation," is recorded in the Transactions of the College of Physicians. f From the descrip- tion and drawing which accompanies it the following chief particulars are learned. The uterus, from a woman aged 30 who had com- mitted suicide, was larger than the ungravid organ ; its body somewhat globular ; its sub- stance, except the cervix, spongy. A decidua nearly \" thick, soft, pulpy, and of yellowish- white appearance, lined the interior of the uterine body. The cervix was filled with gelatinous matter, but not sealed up. The vessels of the broad ligament and appendages were remarkably distended ; on the posterior part of the left ovary, which was considerably larger than the right, was a round prominence distinct from the general fulness. The tunics of the ovary at this point were numerously furnished with tortuous blood-vessels; and from careful examination it was clear that there had not been any aperture in the exter- nal membrane ; its surface was perfectly smooth. On dividing the membrane which covered this prominence, a distinct cyst was exposed, which contained an ovum. The in- ternal surface of this cyst was smooth and polished, its external firmly adherent to the substance of the ovary. The ovum was sim- ply in contact with the cyst in two-thirds of its circumference ; in the remaining third it was united to it so closely as to be inseparable. The chorion and amnion were perfectly dis- tinct, and by the aid of a magnifying glass, vessels filled with blood were seen ramifying on the former. A yellowish honey-like mat- ter filled the amnion, but the embryo could not be distinguished. Around the ovum for some distance the ovary was loaded with blood effused into its substance. Except for the statement regarding the de- cidua there is nothing in this account which would be considered significant of pregnancy at the present time when a more perfect knowledge has been obtained of the various conditions of the ovary in health and disease. Changing the names employed to designate .. the cysts, this description would apply either to a follicle preparing to burst J, or to an in- cipient stage of cyst formation. To the lat- ter it approximates more nearly. The smooth and polished inner surface of the containing cyst ; the union, " so close as to be insepa- rable," of the cyst termed the ovum by a third * Memoir on Extra-Uterine Gestation, p. 33. t Vol. vi. p. 414. 1820. j See ante, p. 557. of its base to the larger one ; the presence of a honey-like matter filling this inner cyst, which is represented in the engraving as not larger than a pea, and the vessels ramifying on the cyst wall, are all conditions commonly ob- served in early stages of the morbid follicle. On the other hand, the following are among the conditions which oppose the conclusion, that the ovary was in this case the seat of im- pregnation, viz., the absence of all trace of an embryo ; the so-called chorion, entirely want- ing villi, which, in all known cases of the early ovum, more or less cover its surface ; the firm adhesion by a third of its circumference, at a time when the ovum naturally lies free and unat- tached even by any part of its little flocculent villous coat ; the impossibility of accounting for chorion-vessels, without an embryo to form them, and still more of explaining how the seminal fluid could reach the ovum through a membrane which is described as " perfectly smooth," and in which, " from careful exami- nation, it was perfectly clear that there had not been any aperture ; " the absence of all mention or representation of any of those conditions of the walls of the ripe follicles which in an earlier part of this article have been shown to be always present in the fol- licle preparing for or soon after rupture, and which must have been present in some degree if this had been a Graafian vesicle containing an impregnated ovum. These together con- stitute insuperable objections to this case being received as one decisive of impregnation in the ovary, and justify its being regarded rather as an example of cystic formation, which, ac- cording to the engraved representation of the parts, it very accurately resembles ; notwith- standing that the description of the uterus and decidua would give a strong bias and in- deed wish to receive this as a case in which impregnation had obtained, if the state of the parts found in the ovary had corresponded with what is now known to be characteristic of the structures formed in the earliest stages of pregnancy.* * I am enabled to add in a note the following particulars relating to two of the four cases quoted above as examples of supposed ovarian gestation, and of which it may be remarked that neither are of recent date, the one having occurred thirty-eight years ago, and the other at least as early* — at a time, therefore, when ovarian gestation had not been questioned, and the ovarian ovum in man had not yet been discovered. The preparation, de- scribed and figured by Dr. Granville as belonging to the late Sir C. M. Clarke, is now in the possession of Mr. Stone, by whose kindness a more particular examination of it has been permitted. For this purpose, the preparation was recently placed in the hands of Professor Owen, by whom it was removed from the bottle, and minutely examined under spirit. At this investigation, I was also present, together with Mr. Stone and Dr. John Clarke, and I had the opportunity of making repeated microscopic exami- nations of every portion of the ovarian structures. The result of "the investigation showed that the structure supposed to be an impregnated ovum con- tained in the ovary, although it had such a general appearance as might without this examination have borne the interpretation which had been originally put upon it, was nothing else than an ordinary ova- OVARY — (ABNORMAL ANATOMY). It is not necessary to multiply these ex- amples, for no additional points of evidence could be produced which are not contained in the foregoing cases. They have been selected from instances related or quoted by various authors who have been strongest in their advocacy of the doctrine of ~H strict ovarian gestation, and they serve to exhibit the kind of evidence upon which that doctrine is founded. All the cases which have been employed to support this view* will be found on examination to belong to one or other of the following divisions : — 1. Cases of cysts without any embryo, and in which some supposed resemblance has been traced between the cyst walls and foetal mem- branes, without any conclusive evidence of the presence of these structures being given. riau cvst. The walls of the sac showed no separa- tion into distinct membranes, and no trace whatever of the structures characteristic of either chorion, chorion-villi, amnion, or decidua could be discovered in them. The outer surface of the cyst was so firmly ad- herent to the surrounding ovarian stroma that it could only be separated from it by considerable traction. "The connecting medium was the common stroma of the ovary. The walls of the cyst, when Y>ortions were examined by transmitted light, ex- hibited the arrangement of vessels peculiar to ova- rian cysts. The little slender depending fragment, supposed to be a rudimental umbilical cord, and very faithfully represented by Dr. Granville in Plate VIII. of the work quoted in the text, proved to be a narrow flap of the same cyst wall which had been left hanging from the edge "of the sac where a por- tion had evidently been originally cut away in order more fully to display the preparation (the sharp edge left here by the knife or scissors being very distinctly seen). Upon transverse section of this little fragment, no trace of umbilical vessels could be found in it. ' It should be observed that Sir Charles Clarke never published an account of this case. The additional particulars which I am enabled to give with regard to the last of the four cases quoted in the text, and described in the Transactions of the Royal College of Physicians for 1820, are of another kind. That this preparation was formerly preserved in the anatomical museum of St. Bartholomew's Hospital, where the author of the case was also the lecturer on anatomy, can scarcely be doubted, from the description, exactly according with it, which appears in the first edition of the Catalogue drawn up by Mr. Stanley. (See Description of the Pre- parations contained in the Museum of St. Bartho- lomew's Hospital, 1831. Edited by Edward Stanley, Esq. Preparation 64, series xx. p. 27.) This pre- paration is no longer contained in the museum ; and by those who are most likely to be informed upon the subject, it is not known to be in existence. The only clue that I can obtain as to its fate is derived from Mr. Paget, who informs me that, as a step pre- liminary to the formation of the new catalogue, printed in two volumes in 1846-51, the entire ana- tomical collection was carefully reexamined; and that those preparations which" were found, upon such examination, not to bear out the descriptions given of them in the catalogue, or which did not serve to illustrate any point of interest, were put aside and condemned. There is, therefore, every probability that this preparation, which can now no longer be appealed to in support of the possibility of ovarian gestation, has been subjected to a similar ordeal to the former, and with a like result. 589 2. Cases of dermoid cysts containing fat, hair, teeth, and bones, the nature and origin of which, independent of pregnancy, have been already considered. 3. Cases in which the evidence is more or less complete that a foetus is or has been con- tained in a cavity of, or connected with the ovary. Of the latter, as already stated, those alone suffice for examination in which the cyst has continued unattached to surrounding parts, and has remained unaffected by dis- integrating and destructive processes. In this category would still be found, in all pro- bability, a sufficient number of cases amply to have determined the question in dispute, if such methods of investigation had been pursued as the present state of anatomical and physiological science demands for the settlement of doubtful points ; for in a considerable number of cases it is rendered evident that the foetus is contained within a sac in some way connected with or occu- pying more or less the usual seat of the ovary. Here, therefore, the question is re- duced to very narrow limits, Are these sacs formed within and at the expense of the proper ovarian structures, or are they adven- titious cysts growing externally to, although connected with these structures?* If strictly within the ovary, and formed of it or of its parts, then ovarian gestation in the strict sense obtains. But this has not yet been anatomically demonstrated in such a manner as to set all objections at rest; for neither have the blood-vessels been injected in order to ascertain their new relations and distri- bution, nor have the tissues been micro- scopically examined, without which exami- nation it would be hardly possible to determine of what parts the foetus-bearing sac is com- posed. Nor have the exact limits of the serous and albuginean coats, nor the relations of the sac to the remaining ovarian tissues, nor the precise mode of connection of the foetal membranes with the sac, been accurately traced. Nor has the condition of the yellow or corpus luteum coat of the follicle, of which brief mention only is made in one instance, been carefully examined ; yet this is a point of the greatest interest and importance, be- cause, if true ovarian gestation ever occurs, then the yellow ovisac would become the decidua, and the outer fibrous coat of the follicle, together with the ovarian tunics and stroma, would be theutertis of the ovum. But in the present state of our knowledge it can- not be said that the subject of ovarian ges- tation stands in any other position than that of an open question, the chief points of in- terest regarding which may be thus stated : — The unimpregnated ovum is known to quit the ripe Graafian follicle by passing through an aperture spontaneously made in the walls of the follicle and of the ovary, in order to enter the Fallopian tube and uterus, in one of which canals it is afterwards impregnated. * A large collection is contained in the work of * It is thought by Boehmer that these cases Dr. Campbell just cited. might be divided into external and internal. 590 UTERUS AND ITS APPENDAGES. It becomes a question whether this law, which has been established by ample tes- timony, admits of the exception that the ovum may be impregnated before quitting the follicle, and therefore whilst still contained within the ovary. The records of various cases, in which the fetus is apparently contained within the ovary, raise this question. For if the foetus is found strictly contained within structures properly ovarian, then the ovum must have been impregnated within the ovary, and the seminal fluid must have entered the Graafian follicle*, for it cannot be supposed possible that the ovum, having quitted the follicle unimpregnated, should again enter it after being impregnated. The cases, however, which have been re- corded as examples of ovarian gestation do not suffice to demonstrate that the sac con- taining the embryo or foetus and its mem- branes is strictly within the ovary, and is com- posed of structures strictly ovarian ; and until such demonstration has been given, ovarian gestation, in the most liberal view that can be accorded to it, cannot be held to have any other signification than that of the develop- ment of the embryo or foetus in a sac con- nected with or occupying the usual seat of the ovary, but not yet proved to be developed within the proper structures of that gland. Origin of Ovarian Cysts in general. — It has been often asserted, and as frequently doubted or denied, that these cysts derive their origin from an unnatural enlargement or dilatation of Graafian follicles. Such a contrariety of views is observable equally with general pathologists, as with those who have studied the special histology of this subject. Of the latter both Rokitansky and Wedl may be considered as still holding uncertain opinions ; for Rokitansky, who regards it as probable that the simple cysts are in many cases developed from the follicles, doubts that such is their origin in those instances in which their number far exceeds the usual number of Graafian vesicles, holding them to be new formations ; and Wedl says that of the cysts in the parenchyma of the ovary no direct proof has ever been given that they originate in the Graafian follicles; and with respect to those which contain hair and teeth, he re- gards their origin in this way as "extremely doubtful." It is obvious that a question of this kind cannot be definitively settled except by mi- nute examination of the morbid cyst in all the early stages of its growth; an exami- nation for which opportunities cannot very frequently arise. The choice lies between the classing of such cysts with those, on the one hand, which originate in the dilatation of * There is nothing in this supposition incompa- tible with the known facts relative to the spon- taneous opening of the follicle, and the power of penetration of the spermatozoa occasionally as far as the distal extremity of the oviduct, or even to the surface of the ovary. natural sacculi and ducts, or with such as have their commencement in the enlarging of areolar spaces, or in the growth of primary cells or nuclei into cysts. In the case of the ovary, it happens that the settlement of this question is more diffi- cult than in that of most other organs ; for with regard to the formation of cysts upon the latter plans, whether the views of Wedl be adopted, that they consist in an excessive augmentation of volume of the areolae of the areolar tissue, or those of Rokitansky, that a cyst proceeds from an elementary granule which grows, by intus-susception,into a nucleus, and this into a structureless vesicle, in both views such cysts come to be com- posed ultimately of a cell-wall compounded of fibrous tissue and lined by epithelium — a structure which is, in fact, identical in com- position with the Graafian vesicle itself. With regard to any doubts as to the origin of cysts in Graafian follicles, which may be founded upon their number exceeding the average number of healthy follicles in an ovary, it need only be observed that the latter have been shown by the microscope to be innumerable ; and with respect to secon- dary cysts, springing from the walls of pri- mary ones, numerous observations prove that the impulse to cystic formation once given in an organ, even by the primitive enlargement of normal cavities, a marked tendency to the antogenous formation of cysts follows.* But even if no other explanation could be offered, the discovery of Barry, that the walls of a Graafian follicle in a natural state often con- tain numerous follicles of a second order, would sufficiently demonstrate the capacity of these for secondary cell-growth. In giving the preference to that view which regards the cystic diseases of the ovary as originating in a dilatation of the Graafian vesicles, I have been guided chiefly by the following considerations. In those cases where I have been able to discover cysts in the ovary in a stage of early formation, these have not been of less size than the average dimensions of the developed Graafian follicle. They occur intermixed with healthy fol- licles, and exhibit with them the same histo- logical formation ; their tissues being altered sometimes only in such slight degrees as still to admit of their common origin with the Graafian follicle being shown. There is sometimes exhibited in the same ovary, or in the ovaries of both sides together, a sufficient number of grades of enlargement to constitute a series of cysts, evidently com- posed of similar parts and tissues in various stages of growth. Beginning with the smaller cysts, still con- tained in part or entirely within the ovary, there may be traced cysts of precisely similar formation and structure in every gradation of size up to those examples in which the ovary itself comes to be a mere appendage of the * Lebert, loc. cit. p. 244. OVARY — (ABNORMAL ANATOMY). cyst, or in which the tissues of the healthy organ are entirely expanded and lost in the walls of the sac. And lastly, the occurrence of these cystic formations is limited to that period of life when the Graafian follicle is in a state of activity. They are not found as new for- mations after the usual time at which the follicles have ceased to be discoverable in the ovaries as natural structures, nor do they occur before the period of puberty has arrived, except in cases much more rare than those of an unusually early development of these follicles, or of precocious puberty. These arguments apply more particularly to cysts with fluid contents. How far they may also serve to explain those which con- tain more highly organised products is less obvious. But it must still be remembered that cystic formations of all kinds occur far more frequently in the ovary than in any other part, whilst there is nothing peculiar in the stroma of the ovary, or that portion which is external to the follicles, which would render it more peculiarly liable to cystic for- mations arising out of dilated areolar spaces, than similar fibrous structures occurring in other portions of the body where cysts occur. Solid Enlargements of the Ovary. — These consist of formations of fibrous, and occa- sionally of imperfect cartilaginous tissues, and of osseous concretions, but more frequently of cancerous growths, formed at the expense of, or deposited within, the tissues of the ovary. Of formations of fibrous tissue some ac- count has been already given in the description of the growth of cysts. The new formations of fibrous tissue which take place in the ovary occur chiefly in the cystic parietes, where they are deposited for the purpose of strengthening the walls and enabling them to resist the increasing weight and pressure of their growing contents. But as fibroid tu- mours, or solid growths of the entire ovary, such formations, except those of very small size, are certainly rare, unless they are of a cancerous or cancroid nature. It is probable, indeed, that, excepting the cancerous and cancro'd cases, most, if not all, of the specimens which have been described or preserved in museums as examples of large fibrous tumours of the ovary, have been formed at the expense of the proper tissue of the uterus, and have had noihing to do originally with the ovary, although the latter may be so involved in the mass that its proper tissues can no longer be distinctly traced. Such I had no difficulty in determining to be the case with a specimen preserved in King's College Museum as an example of fibrous tumour of both ovaries ; each sup- posed ovary being of the size of an ostrich's egg, and presenting all the characteristics of the ordinary fibrous tumour of the uterus. It was rendered evident, by dissecting the parts and opening the uterus, which had not been done previously, that these large tumours which hung on either side of the uterine 591 body had been formed at the expense of the latter, for the natural tissues of the fundus and corpus uteri were in great part absorbed into and had evidently contributed to form these masses ; and out of the apex of one of these sprang the uterine end of the Fallopian tube ; a clear proof that this was not an ovary. In this way may be explained the remark of Cruveilhier, that fibrous tumours of the ovary are so perfectly identical with those found in the uterus, that it is sometimes im- possible to determine to which of the organs they have originally belonged ; and also the remark of Dr Baillie, that they resemble in texture the tumours which grow from the outside of the uterus. The absence of the muscular element from the natural tissues of the ovary, and the now well-known fact that the uterine fibrous tumours contain, as one of their characteristic constituents, more or less abundantly the smooth or organic mus- cular fibre of the uterus, forbid the belief that tumours of similar composition to those found in the uterus can be formed within or at the expense of the proper tissues of the ovary. Cartilaginous and Osseous Formations, espe- cially the latter, are not rare in the ovary. They are found chiefly in the parietes of cysts, and also intermixed with cancerous deposits. The process of deposition of earthy matter, which should be termed calcification rather than ossification, occurs here under three principal forms. In fine sections of the more solid structures. or in the thin walls of cysts which are slender enough to be examined without cutting, may be often seen, with a moderate amplifying power, little aggregations of crystals in the form of clavate spicula, clustered round a centre, and forming groups scattered through a fibrous basis. Such tissues are sensibly rough to the finger, and grate under the knife. In the second form the same calcareous materials, consisting of phosphate and carbo- nate of lime, combined with a small proportion of animal matter, occur as plates or laminae, strengthening the walls of cysts ; or in the shape of grains, or larger aggregations, or layers intermixed with the tissues of more solid tumours. In a third form the calcareous matter may constitute an oval or solid mass contained within a small cyst, and resulting apparently from an entire calcification of the inner walls of the cyst. The condition under which true bony structures are found in the ovary has been already considered in another section. (See Dermoid Cysts.) Cancer of the Ovary occurs under the three principal varieties of Colloid, Medullary, and Scirrhous or hard cancer. Most of the large tumours of the ovary, and such of the encysted class as remain still to be described, belong to the variety of Colloid or Alveolar Cancer, generally associated with Cysts. — These might have been classed, 592 UTERUS AND ITS APPENDAGES. as has been done by Rokitansky and Lebert*, But such an arrangement, whilst recognising with the other forms of cystic disease of the an important feature, often, but not always, ovary, on account of the frequency with which this form of cancer is found associated with ovarian cysts, especially of the larger class. observed in colloid cancers of the ovary, of necessity dissociates these cases from other congeneric forms of disease. In this particu- Fig. 398. Colloid cancer of the ovary. {.After Cruveilhier.') lar respect colloid cancer appears to stand between the various cystic diseases already described, and those forms of cancer which are not colloid, in the position of one of those " osculent groups " which have been some- times employed in classifications of the animal kingdom as" connecting links, to bring into juxtaposition objects which, though exhibit- ing certain near affinities, could not be in- cluded in one common group, without violence to the principles upon which a natural ar- rangement should be based. Not, however, to enter further upon the disputed question of the nature of alveolar cancer of the ovary, it will suffice to notice those peculiarities which are generally to be observed when the disease affects that organ. Since colloid cancer of the ovary does not generally destroy life until the disease has made great progress, the specimens of ovaries so af- fected which come under our notice are often of large size, filling the pelvis and abdomen, and equalling in bulk the masses of cyst formation of a more innocent type. Such a mass, when incised, may be found to include the entire ovarian structure, which is converted into a collection of cysts, or alveolar cavities, varying greatly in size and in the thickness of their walls. Such a variety is often seen in dif- ferent portions of the same structure. The surface of a section may present in some parts * Rokitansky, however, regards these cases as decidedly cancerous ; while Lebert asserts that the}' have nothing in common with colloid cancer except the gelatinous contents of the cells. the appearance of a fine sponge, the alveolar spaces being condensed and somewhat flat- tened, in consequence of the profusion with which the alveoli have been developed. In other portions 'of the same tumour, and oc- casionally as it were in separate lobules of it, the alveoli are more expanded, and take a round or oval form, assuming the condition of distinct cysts, some of which may considerably exceed the rest in magnitude. These larger cysts may occupy a seat within the mass, or project from its surface ; and probably in this way arise those still larger cystic formations in which one or more large sacs occur, having connected with them masses of alveolar struc- ture such as those just described. The interstitial substance, which constitutes also the boundary walls of the alveoli and fol- licles, is composed of a white, shining, fibrous tissue, upon the density of which chiefly de- pends the general hardness or softness of the mass. This intermediate substance is in some instances so thick that the cysts appear like excavations in a dense medium, but often the cyst walls are so thin that the peripheral follicles project in the form of thin-walled sacs from the surface, and the whole mass is sometimes so feebly supported as to assume the appear- ance of a trembling jelly. The thin-walled cysts are generally richly supplied with blood- vessels. These cysts are filled with a viscid mucous- like material, resembling half-liquid jelly, which is sometimes colourless, but oftener of a gray- ish amber, yellow-green, or reddish hue. Im- THE PARC VARIUM— (NORMAL ANATOMY). bedded in the jelly-like substance may be found opaque white masses resembling blanc- mange or thick cream. Intermixed with these contents, in varying proportions, are found nucleated epithelial cells, oval corpus- cles, oil granules and molecules, and delicate filaments. Besides these contents of the alveoli, there may be often observed hanging into their in- terior, and sprouting from their walls, clusters of leaf-like clavate or villous processes, such as are observed in that variety which has more particularly received the name of villous cancer. But it frequently happens that the alveolar type of structure* is not generally diffused through the mass. This may form only a small portion of the diseased ovary, whilst the greater part is composed of one or more large cysts, with contents similar to those just described. Within such cysts, or growing from the walls of those which present no other type of malignant structure, may be observed round or oval bosses, bearing no inapt resemblance to the uterine cotyledons of the cow, and ex- hibiting in section the compact areolar tex- ture characteristic of the closer forms of alveolar cancer. Colloid or alveolar cancer is occasionally found associated with medullary disease in the same ovary, whilst its presence there may be accompanied by other varieties of carci- noma in other organs, and attended by a well- marked constitutional cachexia. Medullary Cancel- of the ovary is of less frequent occurrence than the preceding variety, but like it is also occasionally associated with the formation of cysts. Medullary cancer may occur either in the form of a general infiltration of the entire ovary with encephaloid matter, or in that of distinct tumours, bounded by a fibrous enve- lope, and having the carcinomatous matter distributed through an interior cellular sub- stance, or confined there by cellular septa. These tumours may attain the size of an orange or more. Their growth appears to be in the first instance repressed by their fibrous sheaths, but these occasionally burst and allow of the diffusion of their contents. This form of can- cer often affects both ovaries together, and is found associated with cancer in other and especially adjacent parts. Notwithstanding the number and variety of the contiguous structures which may be thus involved, the ovary may sometimes be traced as the centre or focus from which the cancerous deposit has spread. This was remarkably the case in an example of medullary cancer, which was for some months under my notice, where the disease commenced apparently in the left ovary, and was found to have spread from this point upwards along the chain of ab- sorbent glands on the corresponding side, as far as the pancreas, and outwardly through the ischiatic notch to the gltitaei, and all the ad- jacent muscles, including in its destructive march the os innominatum, which could be Sitpp. 593 cut with a knife like cartilage. A medullary tumour the size of a walnut was found in the fundus of the uterus, but the rest of that organ, as well as the opposite ovary, had es- caped the general destruction. The melanoid variety of medullary cancer is occasionally observed in the ovary. (Roy. Coll. of Surg., No. 2642. and A.) 'it differs only from the foregoing in having pigment cells, of a black or brown colour, scattered through the carcinomatous matter. Scirrhous or Hard Cancer and Cancroid are by no means so common as the two former varieties. Yet it is not rarely that one meets with the ovary, of one or both sides, in a hard white nodulated condition, resembling some- what the human kidney, both in size and shape, and having its entire tissue converted into a form of cancroid, characterised by the de- velopment of a peculiar kind of stiff close-set fibres, containing between their meshes nu- merous nuclei (Fibro-nucleated cancroid). Such a condition of the ovary is sometimes found associated with hard cancer in other parts of the body. * Of Scrofulous Tubercle in the ovary I can give no account. Most authors who refer to the subject mention it as rare, but give no decisive instances. Boivin and Duges, how- ever, have figured an example (Jig. 16. Atlas) occurring in a girl of 16, associated with tuberculous disease of the mucous membrane of the uterus. In cases of my own, which I had regarded as examples of scrofulous ovary, until submitted to the microscope, I could find no trace of tuberculous matter. By Rokitansky the existence of tubercle in the ovary is altogether denied. THE PARO VARIUM. Syn. Corpus Conicum. Neben-Eier stock. Organ of Rosenmuller. These names have been applied at various times to an organ which has hitherto received little attention, but which is nevertheless in- variably present in close proximity to the ovary. The first discovery of this body is due to Rosenmuller f, who termed it the corpus conicum. It has since come under the notice of many observers, and particularly of J. Mliller. And it has recently been re- examined, and very accurately described by Kobelt J, in an essay devoted to this subject, in which the author expresses his surprise that a structure so easily distinguished both by sight and touch, should have attracted comparatively so little attention up to the pre- sent time. The Parovarium is most readily found by holding up the broad ligament between the observer and the light. Within the folds of this membrane, at the part where the layer * For an example see Roy. Coll. of Surg. prep. 2636. t Quaedam de ^variis Embryonum et Fostuum humanorum. Leipsise, 1802. J Der Neben-Eierstock des VVeibes. Heidel- berg. 1847. Q Q 594 UTERUS AND ITS APPENDAGES. of peritoneum, after investing the Fallopian tube, passes off towards the ovary, to form the posterior duplicature which encloses the vessels proceeding to that organ, will be found a small plexus of white tortuous tubes, (fig. 403. a, b,c) arranged somewhat in the form of a cone whose apex is directed towards the hilum of the ovary /, and its base a c a to- wards the Fallopian tube h. The entire or- gan measures about one inch in breadth, and is composed of J2— 20 tubules 0'15— 0'2'" in diameter. The tubes which contain nothing but a clear fluid consist of fibrous membrane, lined by a single layer of pals, cylindrical, epithe- lial cells. These tubular canals are not known to have any direct communication with the ovary. That the parovarium is formed out of the Wolffian body does not now appear to admit of doubt. It has been usually considered that the Wolffian bodies are organs peculiar to foetal life, and that they afterwards entirely disappear in both sexes. Hence no special investigations have been undertaken with a view to ascertain their ultimate fate. Meckel indeed compared them to the epididymis. Rathke believed that they became epididymis in the male, and disappeared in the female ; while Rosen miiller, who discovered the paro- varium, compared this body to the epididy- mis. Some general conjectures also have pointed in themalesexto thevascu/a aberrantia of the epididymis, and in the female to the or- gan of Rosenmiiller and the ducts of Gartner, as the supposed remains of the Wolffian body. Nevertheless it is, according to Kobelt, an undoubted anatomical fact that each pretended ephemeral structure not only exists through the whole of life in both sexes, but that it absolutely increases up to its highest state of perfection, and first suffers a gradual re- trogression, after the extinction of the repro- ductive function, but never entirely disappears. The signification and true homologies of this singular organ cannot be understood without first briefly examining the mode of formation and development of the Wolffian body, and tracing its relation to the genera- tive gland and Fallopian tube. In this exa- mination it is also of consequence to compare the progressive steps of formation of those parts with the corresponding structures in the male. The Wolffian body is most readily exa- mined in the chick, (figs. 399, 400.) Here during the third day of incubation are formed two canals which extend along the sides of the vertebral column, from the heart to the posterior extremity of the body. To the inner side of each canal is attached a series of blind pouches (fig. 399. c and 400. b), which during the next two days become lengthened and convoluted. These together constitute the Wolffian body. Behind them, and formed independently at a somewhat later period, lie the kidneys (Jig. 399. and 400. a) and supra- renal bodies, (fig. 399. /, 400. d) and as these increase, the Wolffian bodies diminish. The testes (fig. 399. e) and ovaria (fig. 400. c) are developed upon the inner border, and in front of the corpora Wolffiana. Fig. 399. Kidneys, Wolffian bodies, and testes of an embryo bird. Magnified. (After Miiller.) a, kidney ; b, ureter ; c, Wolffian body ; d, excre- tory duct of the latter, which, according to the views of Mtiller and Kobelt, afterwards becomes the vas deferens; e, generative gland, afterwards be- coming testes; /, supra- renal capsules. In the female chick, according to Miiller, there is always seen an oviduct (fig. 400. g), Fig. 400. Kidneys, Wolffian bodies, ovaries, and oviducts of a foetal bird, at a period when both oviducts are still of nearly equal size. Magnified. (After Miiller.) a, kidney ; b, Wolffian bod}', c, ovary, the right * rather the smaller; d, supra-renal capsule ;/, ex- cretory duct of the Wolffian body, which in the female becomes obliterated, but in the male is con- verted into vas deferens ; g, duct of Miiller, after- wards oviduct or Fallopian tube. * The drawing has been reversed in engraving. The left, therefore, should be here the right side. THE PAUOVARIUM— (NORMAL ANATOMY). distinct from the duct of the Wolffian body (Jig. 400. /). In the male, however, he has been able to detect no vas deferens distinct from the excretory duct of the corpus Wolffianum ; but on the contrary, the testis and the excre- tory duct of the former body seem to become connected by means of vasa efferentia. This is an important point, because it will be found so far to bear out the views of Kobelt re- garding the homologies of these structures. In the mammalia generally, and in man, the Wolffian bodies are less extended. They, however, possess the same arrangement of transverse caecal tubes ( Jig. 401. a — rf), ter- minating in the side of a common excretory duct (e), which leads from the lower extre- mity of the organ to the uro-genital sinus. These structures are all formed indepen- dently of the kidneys and supra-renal cap- sules, as well as of the ovaria and testes, which parts occupy the same relative position in mammalia as in birds. But here, according to Miiller's researches, a different arrangement is observed in regard to the efferent duct of the generative portion of these structures. At first the oviduct and the vas deferens have each the same confor- mation, and each terminates by a free extre- mity. This, in the female, merely acquires an open mouth, and thus the Fallopian tube is formed, the ovary continuing, as at first, distinct and separate. But in the male the efferent tube and the testis become connected by transverse vessels, which are afterwards converted into the coni vasculosi of the epi- didymis, whilst the rest of that organ is com- posed of the convolutions of the efferent tube itself. " The Wolffian bodies entirely dis- appear in both sexes, and are not converted into any other organ." * These views, however, leave unexplained many peculiarities which are observable in the permanent condition of the parts or or- gans developed from the foetal structures ; and it is the great merit of Kobelt's re,,- searches that they serve to render these in- telligible. According to this observer, there exists, in the earliest periods of intra-uterine life, a condition of indistinction of sex in every in- dividual. This depends upon a temporary co-existence in each individual of all the ele- ments of the reproductive structures. For at the highest point of sexual indifference, that is, shortly before the beginning of the division of sex, the Wolffian bodies consist of — 1. The so-called caecal tubes (Jig. 401. a — d). 2. Of the common duct (e) running along the outer side of this body, into which the caecal tubes open. 3. And of a second longer cord (h), which begins in a blind pouch (i), and takes its course inwards over the Wolffian body, pa- rallel with the excretory duct of the 'latter (e), in order to enter the uro-genital canal (x) , by a separate orifice (&). This last cord, * MUller's Physiology, by Baly, p. 1637. 595 discovered by John Miiller, is throughout destitute of any connection with the caecal pouches. (See also/g. 400. g.) Fig. 401. The left Wolffian body at the period of indistinction of sex. (After Kobelt.) a a, entire collection of its component tubules divisible into three sets, viz., b, upper ; c, middle ; d, lower set ; e, excretory duct of the Wolffian body into which all the tubules open, subsequently con- verted into vas deferens in the male, and becoming atrophied in the female; /, terminal bulb of the same, becoming afterwards the so-called hydatid, often seen attached, in the male, to the head of the epididymis (Jig. 402. /), and in the female to the broad "ligament (Jig. 403. f and 408. g ) ; g, open- ing of the Wolffian body into x, the uro-genital canal ; //, duct of Muller, afterwards Fallopian tube in the female, and becoming atrophied in the male ; i, ter- minal bulb of the same, becoming the hvdatidof Mor- gagni (fig. 402. i) in the male, and the* hydatid often seen depending from the mouth of the Fallopian tube in the female (Fig. 403. i and 368. ee ) ; k, junc- tion of the duct of Stiller with the uro-genital canal ; * shows the subsequent horizontal position of this duct when it has become Fallopian tube. The organ destined for the preparation of the reproductive material, the generative gland, (Jig. 401. / ), consists of a longish, clearly defined structure, lying upon the inner side of the Wolffian body, so as to cover a portion of the bulbs of the caecal pouches. Its white colour serves to distinguish it, at a glance, from the yellowish brown Wolffian body. As yet, no material nor actual distinc- tion of sex can be discovered in any one of these parts ; and yet the whole already con- tains all the elements of the male, as well as of the female, reproductive apparatus, without any true exhibition of hi-sexuality. The nature of the first impulse towards a division of sex, in one or other direction, is unknown, but the subsequent separation ma- nifests itself with the commencing distinctive development, and correlative retrogression of each several element ; for the cardinal organ, the generative gland (Jig. 4:01. 1), may be con- verted into testis (Jig. 402. /), or ovary (Jig. 403. /), and through the doubly existing ex- cretory duct of this gland, viz. the duct of Muller (Jig. 401. £), for the female, and the Q Q 2 596 UTERUS AND ITS APPENDAGES. excretory duct of the Wolffian body (fgAQl, e) for the male, the capability of conver- sion into either sex exists at this time in every individual. The division of sex begins to be anatomi- cally discoverable by the development of one, Fig. 402. Adult testis and epididymis, anterior view. (After Kobelt.) a a, entire series of metamorphosed tubules of the original Wolffian body ; b, remains of the upper set, converted into the hydatid in the head of the epidi- dymis; r, the middle set converted into the coni vasculosi ; d, the lower set converted into the vasa aberrantia ; e, excretory duct of the Wolffian bod}', now the canal of the epididymis and vas deferens ; /, bulb of the same, now a so-called hydatid ; h, duct of Miiller, not destined to be developed in the male ; i, terminal bulb of the same, now the hydatid of Morgagni ; g, hydatiform swellings of the same in the border of the epididymis ; /, generative gland, now testis. and the stationary condition or disappearance of the other of these ducts. From this point, therefore, the course which each of these organs takes, is different for either sex. The male Wolffian body never disappears in all its parts, but is converted into the epididy- mis in such a manner that the middle line of cascal tubes (fig. 401. c c) is transformed into the 18 — 20 coni vasculosi (fig. 402. c) ; while their straight and open ends, as vasa efferen- tia, establish a communication with the rete vasculosum testis. The upper blind pouches (figAQ\.ay b) and the bulb (/) of the excre- tory duct disappear, or become converted into the hydatids (fig. 402. b, /) upon the head of the epididymis, while the inferior pouches (fig. 401. d) disappear in part, and in part become elongated and tortuous, without forming any connection with the testis. These constitute the hitherto enigmatical vasa aber- rantia of Haller (fig. 402. d). The excretory duct of the Wolffian body (fig. 401. e) is converted into the canal of the epididymis, (fig. 402. e), and ultimately into the vas deferens, and whilst the retro- gression and final obliteration of the terminal part of this duct takes place normally in the female, (fig. 403. e} it constitutes a patho- logical condition when it occurs in the male. The terminal bulb (fig. 401. i) of the duct of Miiller is converted into the hydatid of Mor- gagni (fig. 402. i), whilst its inferior por- tion (fig. 401. h) still exists, at a later period in the anterior border of the epidi- dymis (fig. 402. /z). Tracing the development of the corre- sponding structures from the same point of departure as in the male, we find that in the female, also, the Wolffian body never dis- appears entirely, but is employed in the for- mation of the parovarium. Its middle blind Fig. 403. Adult parovarium, ovary, and Fallopian tube. (After Kobelt.} a a, entire series of tubules of the original Wolffian body ; b, remains of the upper set, which occasionally become distended by collections of fluid, and constitute one form of dropsy of the broad ligament ; c, middle set of tubules forming the principal part of the parovarium ; d, lower set atrophied, answering to the vasa aberrantia in the male ; e, atrophied remains of the excretory duct of the Wolffian body ; /, terminal bulb of the same, converted here into the hydatid often seen attached to the broad ligament ; h, the former duct of Miiller, now Fallopian tube, with its infundibulum, from which hangs i, the terminal bulb, now converted into a pedunculated hydatid ; /, generative gland, now the ovary. These three last figures are from Kobelt, whose views they illustrate. The letters refer to correspond- ing parts in each. FALLOPIAN TUBE OR OVIDUCT — (NORMAL ANATOMY). 597 pouches (Jig. 401 . c c), are converted into the 18 — 20 tubules of the parovarium (fg.4O3. c), and these secerning tubes become organi- cally connected with the hilum of the ovary, /. They are the homotypes of the male coni vasculosi, and vasa efferentia, but which con- stitute here vasa adferentia. The superior blind pouches and the bulb of the excretory duct disappear, or contri- bute to form the hydatids at the outer border of the parovarium (fig. 403. fb\ which are so commonly mistaken for morbid struc- tures. The inferior blind pouches (fig. 401. rf) remain and represent the vasa aberrantia of Haller (Jig. 402. rf), in the male. Several of them become elongated and intermingled with the vessels of the spermatic plexus (fig. 403. d). The excretory duct of the Wolffian body (./%• 4-01. e) in the female, undergoes a retro- gression in its whole length, and the lower end disappears entirely. (Fig. 403. e). The duct of Miiller (fg. 401, h) is con- verted into the Fallopian tube (fg. 403. h), and its bulb (fig. 401. i) becomes the terminal hydatid of the same (fig. 403. i). This latter structure, of which a very excellent example, as occurring on both sides, is given infg. 368. e et is very constantly present in the adult. Like the so-called hydatid (fg. 403./and 408. g) at the outer border of the parovarium, it is frequently mistaken for a morbid product, and is often so designated in descriptions of these parts ; an error which the improper title of hydatid tends to propagate. The interruption or deficiency of the Fal- lopian tube in the female is a malformation, which represents a normal condition in the male. The parovarium exhibits parallel stages of development and retrogression with its corre- sponding ovary at different periods of life. Abnormal Anatomy of the Parovarium. — So little attention has been given to this structure in its natural condition that accu- rate information regarding its morbid states can hardly be looked for. The so-called hydatids, which are found at the outer bor- der of the parovarium in most adult speci- mens, and which are constructed out of the superior blind pouches and bulb of the ex- cretory duct of the Wolffian body, have been already just noticed as normal structures. These are found pretty constantly in younger subjects, while the hydatids of later forma- tion in the alae vespertilionum are formed of the remains of the canals of the retrograde parovarium. Within the walls of these canals is collected occasionally a considerable amount of fluid, and it is probable that this is the origin of those larger accumulations to which the term dropsy of the broad ligament has been applied. FALLOPIAN TUBE OR OVIDUCT. NORMAL ANATOMY. TubfB uteri vel Fallopiance ; oviducti ; vasa spermatica vel ejaculantia, Lat. ; Muttertrom- peten, Germ. ; Trompes uterines, Trompes de Fallope, Fr. The Fallopian tube (fg. 368. c c, and 404. a b c) is the excretory duct of the ovary, as its homotype, the vas deferens, is the excretory conduit of the testis. And while in an anatomical point of view the tube is an appendage of the uterus, in a physio- logical sense it must be regarded as the proper appurtenance of the ovary. But the Fallopian tube differs from the vas deferens, as well as from every other excretory duct in the animal economy, in this important particular, that it is entirely detached from its proper gland, between which and the uterus it serves to establish only a temporary communication. This separation of the oviduct from the ovary is associated with a higher type 0f general structure than that which accompanies the blending of these parts. It is first ob- served in the cartilaginous fishes, and prevails in all classes of the animal kingdom above them ; while in the osseous fishes and in the invertebrata possessing distinct ovaries, the oviducts are directly continuous with those bodies. The Fallopian tube or oviduct is developed equally on both sides of the body in all vertebrate animals, except in the class Aves, where the right tube becomes atrophied at an early period, while the left alone is de- veloped. In the human subject each ovary is pro- vided with its proper oviduct, which serves to convey the ova from either side to the central organ, the uterus. But the detached position of the oviduct permits so great a range of motion in its free extremity, that, not only can this be applied to every part of the surface of the corresponding ovary, but the tube of one side may occasionally serve as a conduit to the opposite gland, and re- ceive its product. The action of the tube, however, is then imperfect ; and, when im- pregnation obtains, an abnormal form of ges- tation usually results. Form and dimensions. — Each oviduct has the form of a conical tube, the base of which is free and directed towards the ovary, while its apex is attached to the corresponding superior angle of the uterus, out of which it appears to arise. The form of the tube was compared by Fallopius to that of a horn or trumpet, which instrument, when straightened or only slightly curved, it sufficiently resembles. Issuing from the upper angle of the uterus, at the point of junction of the superior and lateral borders, the oviduct commences round and narrow (fg. 404. e), and proceeds outwardly gradually and regularly widening up to its dis- tal extremity, where it contracts somewhat QQ 3 598 UTERUS AND ITS APPENDAGES. suddenly just before terminating in a widely expanded funnel- shaped orifice. In the latter half of its course the tube exhibits certain flexuosities, which produce an appearance of contraction at intervals. But that no such contractions really exist is rendered evident by Fig. 404. Left Fallopian tube from an adult. (After Richard.} a, pavilion and fimbrise ; b, body of the tube ; c, abdominal orifice ; d, tubo-ovarian ligament and fringes ; e, commencement of the tube ; ff, tubal mesentery ; g, ovary ; h, ligament of the ovary ; i, uterus ; /, round ligament. distending the tube with air or water ; a pro- cess which invariably removes tbis appearance, and serves to demonstrate the uniform and equable enlargement of the canal. The length of the tube varies in different subjects, and to a .slight extent on the two sides of the same subject. But this difference is not nearly so marked as that often ob- served between the respective distances of the two ovaries from the uterus. The ordi- nary range of length of the tube, measured between its extreme points and disregarding the flexuosities, is 3^ — 4^"; but the curvature and flexuosities add usually 1 — 1£" to this length. The breadth of the tube is considerably greater at the distal than at the proximal end. Just at the point of emergence from the uterine border, where the tube is firm and cord-like (fig. 404. e\ its external diameter is 1£ — 2'". From this point it gradually increases in breadth, and becomes softer, so as to assume the general appearance of an intestine. The mean diameter of the tube is found at about three-fifths of its length (b) from the uterine end, where it measures 2%" ; from this point the enlargement is more rapid, until the greatest diameter is attained just before the terminal contraction occurs, and here the transverse measurement is 5'". Situation and connections. — Of the three structures termed appendages which arise in •a triangular form from the superior angle of the uterus, the Fallopian tube occupies the apex of the triangle, while, at nearly equal distances from it are inserted the ligament of the ovary, and the round ligament ; the for- mer posteriorly, and the latter anteriorly. In the natural position of the parts, the tube, viewed from without, appears to spring from the uterine angle with a slight downward curve (fig. 404. e), and then inclining hori- zontally forwards and outwards, it describes an irregular semicircle, whose inner side looks backwards towards the ovary (g), which is placed nearly opposite to the centre of its length (figs. 368. and 404.). Such at least are the relative situations which these parts exhibit when spread out equidistantly from each other : although it is probable that during life they are more collapsed and lie closer together, — the anterior wall of the tube then being in apposition with the sides and back of the bladder, while its pos- terior wall corresponds, at its centre, with the ovary, the superior border with the small intestine, and the inferior with the fold of peritoneum by which the tube is at- tached to the broad ligament. The mouth or abdominal end of the tube is generally directed inwards and backwards, towards the distal extremity of the ovary, in close proxi- mity to which it is preserved by means of the tubo-ovarian ligament (figs. 368. n and 404. d). The fold of peritoneum (fig. 404. /), which connects the tube with the main por- tion of the broad ligament resembles a mesentery and serves to convey blood-vessels and nerves, as well as to sustain the tube in its place, and to limit its movements. It constitutes that portion of the broad ligament FALLOPIAN TUBE OR OVIDUCT — (NORMAL ANATOMY). termed the middle wing. The Fallopian tube occupies the entire upper border of this wing, and receives from it a complete perito- neal investment, except along the lower bor- der or line of junction of the two surfaces of membrane composing it, at which line the ves- sels and nerves enter. Thus the tube resembles an intestine in the mode of its investment, but with this difference, that the peritoneal coat is more loosely applied, especially in young subjects ; where the convolutions of the tube are more distinctly marked, and lie free within the sheath, which does not follow their windings (fig. 418.).* The tubal mesentery (fig. 404. /) is tri- angular, or somewhat falciform in shape. Its narrow pointed end is directed towards the uterus, where the tube has scarcely any ca- pacity for independent motion ; but as the depth of the mesentery increases outwardly 599 greater freedom of movement is permitted. The greatest breadth of the mesentery is found at a distance of two thirds of its length from the uterine extremity, and here it measures 1£". From this point a slight narrowing occurs, and the membrane ter- minates in an abrupt margin 1 £" in length, which extends from the lower border of the mouth of the tube to the bulbous extremity of the ovary. This border, which is thickened by the addition of a layer of mucous membrane de- rived from the mouth of the Fallopian tube, constitutes the tubo-ovarian ligament (fig. 404. d). Separate parts and divisions. — The full ex- tent of the Fallopian tube cannot be ascer- tained until the entire canal, in its interior, has been laid open. The tube which, ex- ternally viewed, appears to spring from the Fig. 405. Right Fallopian tube laid open. From an adult who had not borne children. (After Richard.) a, funnel-shaped canal leading from the uterus to b, uterine portion of the tube ; c, point at which the large plicae commence ; d, infundibulum covered by plicae, continuous with those lining the canal ; e, tubo- ovarian ligament and fringes ; f, ovary ; g, round ligament. superior angle of the uterus, is thus seen to commence by a small orifice, ostium uterinum, upon the inner surface of the uterus. This orifice conducts to a narrow canal (figs. 405. b and 406.) which, after traversing the walls of the organ, and constituting the pars uterina, expands into a gradually widening tube (fig. 405. r), whose form nearly cor- responds with the external configuration of the part. Towards the extremity of this canal, a sudden contraction occurs, consti- tuting the external orifice of the tube, ostium abdominalc (fig. 404. c). But this does not form the termination of the oviduct, for the latter immediately widens into the trumpet- like orifice (infundibulum), whose margin, split up into numerous fringed processes, * For a further account of the reflections of peritoneum, which enclose the uterine appendages see " Ligaments of the Uterus/* in this article. •mbrus), (fig. 404. a a) give to that part the torn and jagged appearance suggestive of the idea that it has been bitten or torn, as expressed in the name, morsus diaboli, applied by ancient writers to this part. Each of these parts exhibit peculiarities of struc- ture, requiring a special description. Internal, or uterine orifice, ostium uterinum. — This orifice, which ought to be regarded as marking the termination rather than the commencement of the tube, is found at the extremity of a short, funnel-shaped conduit, (fig. 405. a) which leads from the general cavity of the uterus into the upper and outer angle' on either side of that organ. Here, while there is no abrupt line of demaYcation to indicate the point of commencement of the canal, the characteristic structure of the uterine mucous membrane gradually ceases. The peculiar arrangement of its capillary vessels and the orifices of the uterine glands, Q Q 4 600 UTERUS AND ITS APPENDAGES. can no longer be discerned, and a slightly plaited condition of the lining membrane of the canal begins to be distinguishable (fif$. 405. b). At this precise point is found the true uterine orifice of the canal, the diameter of which varies in different subjects, but is rarely of larger size than suffices for the easy pas- sage of a common bristle. The true diameter of the tubal cavity at this point is best ex- hibited by a transverse section ; for when the canal is laid open longitudinally, and its walls are separated as at b, in fig. 405. this portion of the interior of the tube appears to have a greater diameter than it actually possesses when the parts are closed, and in a natural state. In some subjects, however, and in certain conditions of the tube, the uterine orifice may be sufficiently patulous to admit of the passage of a fine probe. Uterine portion of the tube, pars uterina. — This, as just stated, is the portion of the ovi- duct which traverses and is included in the substance of the uterine walls. Its length will vary, in some degree, with the varying thickness of those walls, in different subjects ; yet not entirely so, because this canal does not pierce the uterine parietes in a direction perpendicular to their surface, but traverses them in an oblique manner, while the tissues become gradually attenuated around it, in a direction from within outwards (fig. 405. b). But the course of the tube through the uterine walls may be still more satisfactorily traced by the aid of a section made down to, but not laying open, the canal. The peculiar white colour of the tube is thus made to con- trast strongly with the surrounding darker uterine tissue ; and this peculiarity is ren- dered more striking when a fine injection of the part has been made. The canal of the tube may thus be readily traced from its infundibular-shaped commencement running, in the first half of its course, in a direction obliquely upwards and outwards, and in its remaining half, either horizontally outwards, Fig. 406. Entrance of the Fallopian tube into the uterine cavity, dissected down to the mucous membrane, which is left unopened. (Ad Nat.) or more commonly turning rather suddenly downwards, and forming, with its first di- rection, an angle of 60° (fig. 406. and 431.). Strictly, the Fallopian tube should be deemed to commence at this point ; and this should be regarded as the true ostium uterinum, while the short infundibular canal leading to it from the uterine cavity should be con- sidered a portion of that cavity, representing, in fact, the cornu of the uterus in mammalia. The peculiar form of this portion of the tube is not without interest, for it appears to me to offer a probable explanation of the occa- sional detention of the impregnated ovum, in its passage through this division of the ovi- duct, where its development produces the variety of extra-uterine pregnancy termed by Breschet interstitial. Canal of the body of the tube. — While the portion of the Fallopian tube already de- scribed, as contained within the substance of uterine walls, is rightly termed its uterine or fixed portion, the main part, which is ex- ternal to them, constitutes the free portion. This also is traversed in its entire length by a canal, the form of which corresponds generally with that of the tube itself. It is occupied by numerous longitudinal folds of the lining membrane (fig. 405. c), which are so closely placed as to convert the channel of the tube into a series of minute capillary canals. These folds never disappear by dis- tension like the folds and furrows upon many mucous surfaces, such as the oesophagus, blad- der, &c, ; but they are true plications, like the valvulae conniventes of the small intes- tine, as pointed out by M. Richard, who has very accurately described their arrange- ment.* Each of these is composed of two layers of mucous membrane united together by cellular tissue. Their direction is con- stantly parallel with the axis of the tube. In the uterine region of the oviduct, they con- stitute two or three small projecting and rigid crests, forming the little capillary chan- nels, but in proportion as they advance to- wards the outer part, they become more elevated and numerous, and at 2 or 3 fingers' breadth from the uterus commence the large floating folds which are prolonged as far as the pavilion. These floating plaits are from 4 to 6 in number ; they acquire a breadth of 2 — 3"', and are themselves co- vered by an infinite number of little crests, often imbricated the one upon the other, and intercepting between them little capil- lary canals. On a level with the abdomi- nal opening these large folds cease, the small ones only remaining; but still one of these large folds always extends beyond the ori- fice. External orifice, ostinm abdominale. — This occupies the bottom of the funnel-shaped expansion or trumpet-like end of the ovi- duct, and is formed simply by a constriction of the tubal walls at a short distance from the irregularly notched margin in which they terminate. The aperture is fringed in its entire circumference by the plications of the membrane already described (fig. 405.). These radiating towards the centre appear nearly to obstruct the entrance of the tube, * These, p. 35. PALLOPIAN TUBE OR OVIDUCT — (NORMAL ANATOMY). which, however, during the middle period of life is usually of sufficient capacity to admit easily of the introduction of a moderate- sized catheter. The constriction which forms this aperture is not occasioned by any thickening nor other alteration of texture in the walls of the tube, so that after the parts have been laid open, it is often difficult to determine the exact seat of the previously existing orifice by any mark except that of a slight diminution in breadth of the walls at this spot. The Pavilion, or Infitndibulum consists of the expanded or trumpet-mouthed portion of the tube which lies between the orifice just described and the fringed margin in which the tube-walls actually terminate. No por- tion of the Fallopian tube is so variable in form and construction as this, and yet none is of such importance, for upon the peculiar construction of this part depends the special action of the oviduct in grasping the surface of the ovary, and receiving and conveying away the ovum. The representations which in illustrated works usually accompany the description of this part serve to give but a feeble notion of the beauty of its construction, apparently be- cause the advice of De Graaf, that their structure should be examined under water, has been commonly neglected. But without the support derived from a fluid of greater density than the atmosphere, the extremely delicate plicae and fringes with which the ex- panded mouthpiece of the tube is beset, col- lapse and exhibit nothing more than a ge- neral indication or outline of their true form. When thus examined, the pavilion in young and healthy subjects is observed to be funnel-shaped, and to have arranged upon its inner surface numerous folds and 601 leaflets, which are merely continuations of the larger and smaller plicae lining the cavity of the tube. These folds, which are irregu- larly though often very closely set, con- verge towards the centre of the orifice of the tube, and in some cases appear by their pro- fusion almost to block up the entrance of the canal. The office of these folds is doubtless to receive and entangle the delicate ovum in one of the numerous channels which are formed between the sets of leaflets, and so to conduct it infallibly into the common orifice towards which they all converge. So great is the variety perceptible in the conformation of this structure in different sub- jects, that it would be difficult to find any two in which a precisely similar arrangement of parts obtained. Even in the same body there is often a material difference in the pavilion of the two sides. And these varieties are not attributable to mere individual pecu- liarities of form, but they appear to bear a certain relation to the age of the person in whom they are found*, and consequently to the period of functional activity or other- wise of the structures of which they form an importart part. Thus in young subjects, after the age of puberty, and in those who have borne few children, the pavilion exhibits that richness and profusion of folds and fringes which is represented \nfigs. 404. and 419. while in multiparae and those advanced in life a greater simplicity of form in this part is commonly observed ; but between these extremes every variety of arrangement may be observed. In the foetus, and in very young subjects, the margin of the pavilion is nearly evenly circular. This form is also seen in adults in those rare cases where the prolongation of one of the fimbriae alonij the tubo-ovarian Fig. 407. Portion of Fallopian tube from an adult. (After Richard.) a, external surface of the fimbrije ; i, line of demarcation between the mucous and serous membranes ; c c, body of the tube ; dd, tubo-ovarian ligament, presenting scarcely any trace of the fringes. ligament does not occur, but commonly the unique in the animal economy, viz., the con- margin is uneven or scolloped, as shown in junction of a serous with a mucous mem- fig. 407. brane. The line of junction of these two At this point, the opportunity occurs of „ Richard, These, Anatomie des Trompes de examining an arrange ment of parts which is i'uterus chez la Femme. 1851. 602 UTERUS AND ITS APPENDAGES. surfaces may here be traced along the mar- gin where the tube wall terminates. Here the peritoneal or outer covering of the tube may be observed to cease suddenly in the form of a distinct boundary line, as in the example represented in fig. 407. But oc- casionally the peritoneal coat is prolonged upon the base of the principal leaflets which crest the end of the canal, and in that case a closer examination is necessary in order to discover the line of union between the mu- cous and the serous surfaces. The fimbrice, lacinwe (AOKI'S), or morsus dia- boli. — The structure and composition of these appendages differ in no respect from those of the plicae or folds of which they are merely continuations. These fimbriae present many varieties of form, but are generally either pe- tiolate, lanceolate, or simply filiform. Their margins are in some cases coarsely crenate, like those of the tubal plica?, while in other instances they are so finely indented, as to require the use of a lens for their examina- tion. The greater number of these fimbriae are attached to the sides or margins of the infundibulum by their narrower extremity only, like leaves thickly clustered on the branches of a tree, while the more obtuse ex- tremity of each leaflet is left free, apparently with the object of increasing the extent of surface of the tube-mouth, which may be applied to the superficies of the ovary. But very commonly one or two fimbriae are ob- served to be firmly attached by both ends, while the body extends horizontally in the form of a flattened band among the rest of the fringes, as at fig. 403. d. The backs of these are always covered by a continuation Fig. 408. Abdominal end of right Fallopian tube, from an adult. (After Richard.) «, fimbriae irregularly formed ; cc, bristle passed through an accessory pavilion ; d, horizontal band across the mouth of the tube formed by one of the fimbriae having both ends fixed ; g h, pedun- cle ending in fringed processes, probably the terminal portion of the Wolffian duct. (See fig. 401. /, and explanation.) t, body of Fallopian tube; k, ovary. The tubo-ovarian ligament and fringes are well developed in this specimen. of the serous membrane. It is difficult to imagine a use for them unless they are placed there as a safeguard to diminish the risk of a retrograde movement and escape of the ovum after it has entered the tube along one cf the furrows formed between the plicae. The length of the fimbriae ranges from %" to f". The principal leaflets, being con- tinuations of the 4 — 6 main plicae of the tube, exceed the rest in size, and these, spreading like rays, form the more salient points of the fringes, while the intermediate spaces are filled up by the smaller appendages. Intermixed with the latter are often seen minute pedunculated cysts, and especially little white hard grains, the size of millet seeds, first noticed by De Graaf. Similar grains are often observed upon the mesentery of the tube, or attached to the outer surface of the tube itself (fig. 404.). The Tubo-ovarian ligament and fringes. — This so-called ligament (Jig. 408.) consists of one of the fimbriae, which is almost con- stantly prolonged upon the outer margin or base of the triangular mesentery of the tube. Extending in the form of a slight furrow or channel (fig. 404. d and fig. 405. bourhood of the tubal orifices. The apertures by which the Fallopian tubes enter the upper angles of the uterus are so small as only to admit of the passage of a fine bristle (fig. 406.). That by which the cavity of the body communicates at its inferior angle with the canal of the cervix has an average diameter of 1|'" — 3"'. This orifice is the os uteri internum (fig. 431. i). The following are the dimensions of the ute- rine cavity :— length 11'"— 12'"; breadth be- tween the points of entrance of the Fallopian tubes 11'"— 12'"; at the centre of the ca- vity 4"' ; at the os internum 1£'" — 3"'. The cavity of the cervix consists of a flat- tened fusiform canal running through the centre of the uterine neck. The widest por- tion occurs about the middle, where the canal measures transversely 3£'" — 6'" (fig. 431.cc), whilst towards either extremity the parietes gradually approximate so as to leave a narrow aperture at each end ; the superior aperture being the orifice already described as the os uteri internum, the dimensions of which have been given; — the inferior being the os externum, or os tincae, which measures 3'" — 4"' in transverse diameter. The antero- posterior diameter of the canal at its widest part is not more than !£'" — 2'". The en- tire length of the cervical cavity is 12"' — 13'". The mucous membrane lining this cavity is probably not greatly inferior in extent to that of the uterine body. But on account of the smaller space in which it is contained, instead of forming an even layer, the mem- brane is here thrown into numerous folds or plicae, having intermediate furrows, often traversed by lesser plicas, which extend the secreting surface, and furnish a more consi- derable seat for those numerous mucous crypts which abound upon almost every por- tion of this structure. The forms which the cervical folds or plica? assume are sufficiently remarkable to have attracted the attention of anatomists at all periods. They are, however, so variable, that if twenty specimens be compared to- gether, scarcely two will be found to present precisely the .same arrangement. On this account it is difficult to furnish any descrip- tion of them which shall be universally appli- cable. Nevertheless, two forms appear to me to be more prevalent than others. In one a single prominent raphe occupies the centre of each wall of the cervix. (Fig. 431. c c.) Com- UTERUS— (NORMAL ANATOMY). mencino; sometimes at a distance of 1£'" — 3'" above the margin of the uterine lip and ex- tending upwards either centrally or to one side of the median line, and reaching as far as the internal os, it terminates here in a bulbous expansion, or branches out into numerous small ramifications. From either side of this median perpendicular fold are given off lateral plica?, varying in number, but being usually not less than 6 — 9. These soon bifurcate once or twice, so that the number of folds will vary considerably, according as they are counted immediately at, or at some distance from, their line of junction in the central raphe. The uppermost pair of lateral plicae, or those next to the raphe, often exhibit the same bulbous extremity; and these together fill the upper or narrowest portion of the cer- vical canal. Lower down, where the canal be- comes wider, the lateral plicae spread out on either side of the central raphe, the upper ones in an oblique, the middle and lower ones in a more horizontal direction. These soon bifurcate, and form a series of oblique, hori- zontal, or arched laminae, whose arrangement varies much according to the fulness of the folds, the depth of the furrows between them, and the distance by which the laminae are se- parated. If the latter are prominent and very closely set, their margins may overlie each other, like the branchial laminae of a fish, so that no intermediate furrows are perceptible; or the folds, not being very prominent, may merely lie in apposition, leaving no visible in- terspace until they are drawn asunder ; but when the plicae are less full and prominent a furrow is perceptible between each. These furrows of necessity take the same direction as the plicae by which they are bounded. In another common form which the plicae assume, the general lines of folds and interme- diate furrows take a more vertical direction, so that sometimes as many as six or eight of the more central laminae may be traced run- ning down side by side to the very margin of the cervical lips (fig. 424.). Here often the two most central folds appear to run up from one end to the other of the cervical canal ; but still commonly one of these is more fully developed than the rest ; its upper bulbous extremity occupying the position in the narrow portion of the cervical canal, al- ready described, while its lateral divisions being more numerous than those of the plicae next adjoining, it takes the office of a raphe, though its position may be, as it often is, more or less eccentric. On either side of this principal fold the lateral plicae arrange themselves, inclining more outwardlv in proportion as they occupy a still lower place in the cervix. But in these cases the curves of the lateral plicae are often very abrupt — the laminae rising obliquely up- wards, and then making a sudden downward bend like the ends of the leaves of a lily. This arrangement of the plicae I think I have more often observed upon the posterior wall of the cervix, where the laminae are usually thicker and bolder than upon the anterior 629 wall, upon which the arrangement first de- scribed appears more commonly to prevail. But so various are the forms which the prin- cipal folds of the mucous lining of the cervix assume, that it is not possible to fix upon any one instance whose description, however mi- nute and accurate, will serve as a strict ex- ample of the rest. The more perpendicular the arrangement of the plicae, the nearer is the approach to that form which is most commonly found in the terminal part, or neck of the uterus, in the mammalia generally, where the folds al- most invariably take the direction of the long axis of the canal, reminding us of the ar- rangement of the plicae in the Fallopian tube already described. After repeated pregnancies these plicae become much thickened and the folds more prominent, while their extremities exhibit a swollen and bulbous appearance resembling leaflets attached to the branch of a tree. Hence, apparently, the origin of the old term arbor vitce, by which this structure was com- monly designated; while to the more closely arranged plicae, springing from a central shaft or raphe, the term penniform ntges is more strictly applicable ; and to those cases in which several parallel folds, after ascending ob- liquely, form a series of lateral arches, or suddenly bend over and then downwards, the title of plica palmate, or as some employ it, palmce plicatcs, seems more appropriate. Thus upon both walls of the uterine cervix the mucous membrane, being of greater extent than the surfaces which it lines, is gathered Fig. 432. Portion of cervix uteri Enlarged 9 diameters. (After Tyler Smith, and Hassall.)* * This figure is from a valuable Memoir on the Pathology and Treatment of Leucorrhoea, in vol. xxxv. of th.- Medieo-Chirnrgical Transactions, l*.r_> ; where will be found also a description, with illustrations, of several of the natural and abnormal forms and conditions of the cervix. s s 3 630 UTERUS AND ITS APPENDAGES. into folds whose offices will be presently more specially considered. At ,the lateral lines of junction of the two cervical walls, where a crease or furrow is formed by the sudden bending of the parietes, an imperfect raphe is sometimes found, uniting a portion of the plicae ; but more commonly the laminae of one surface either pass over and become united at their extremities with those of the oppo- site side, or else upon reaching the lateral angles they split up into smaller divisions, which are again gathered into the single folds upon the opposite side, their junction being then effected by the interposition of a cribri- form surface. The central raphe and lateral plicae pro- ceeding from it, under whatever form they may appear, constitute together a series of primary folds, from which others of a secon- dary order are produced. These emerge from either side of the lateral plicag, and, crossing the furrows between them, subdivide again and again until the whole surface presents that cribriform aspect which can be just dis- cerned by the naked eye, but cannot be accu- rately examined without the aid of the mi- croscope. Here also are found in countless numbers these mucous crypts, which appa- rently furnish the peculiar secretions of this portion of the uterus (fig. 432.). Structure and arrangement of the tissues composing the uterus. — The uterus is usually described as consisting of three coats, viz., an outer or serous, a middle or muscular, and an inner or lining membrane, commonly termed the mucous coat. But these coats cannot, like the three coats of an intestine, for example, be separately displayed, because each passes so imperceptibly into the others, that although to the naked eye an apparent distinction may Fig. 433. Section of female pelvis and its contained viscera. (After Kohlrausch,* — reduced.) A, uterus ; B, bladder ; c c, rectum ; D, anterior, and E, posterior lip of cervix uteri ; F, connective tissue uniting the anterior wall of the cervix to the bladder; G, lax tissue between the posterior wall of the cervix and the peritoneum ; n, Aragina. * Zur Anatomic und Physiologic der Bcckenorgane, von Dr. 0. Kohlrausch, Leipzig, 1854. UTERUS — (NORMAL ANATOMY). 631 be observed, this distinction in a great mea- sure vanishes under the application of the microscope. Peritoneal coat. — The outer serous coat, which constitutes the thinnest of the three component tissues of the uterus, is formed of the centre of the principal fold of the broad ligament, which is closely applied to the uterine body and fundus, and to a portion of its neck. It is of great importance to the com- prehension of certain points in the pathology of the uterus, to be hereafter considered, that the relations of this peritoneal covering to the^roper structures of the organ, as well as to adjacent parts, should be accurately deter- mined. The most important of these rela- tions are shown in fig. 433., representing a vertical section of the pelvis and its con- tents. In this view the reflexions of peri- toneum over the centre of the uterus are shown. The membrane, after lining the abdominal walls, and covering the fundus, and a portion of the posterior surface of the bladder, is suddenly arrested in its descent at a point very nearly opposite to, but some- times a little below the internal os uteri, and therefore about the seat of junction of the body with the neck of the uterus. Here the membrane forms a sharp fold or angle, and becomes immediately applied to the anterior face of the uterine "body, while the cervix, which lies in great part, if not entirely, below this level is left uninvested. The peritoneum, then, after ascending over the anterior uterine wall, covers the fundus and sides of the organ, and descending upon the posterior surface, it remains closely adherent to the tissues be- neath, until it reaches the level of the anterior point of reflexion. At this point the perito- neum becomes much more loosely connected with the uterus by the interposition of a quantity of lax connective tissue which inter- venes between it and the posterior cervical wall (fig. 433, G). The membrane, however, still descends, covering first the posterior wall of the supra-vaginal portion of the cervix, and then a part of the fornix, or upper end of the vagina. The extent of peritoneal covering which the vagina receives, varies in different subjects from half an inch to nearly an inch. The membrane then, as before, turns upwards, but at a more obtuse angle, to invest the rec- tum, so that a pouch is formed, termed the recto-vaginal or retro-uterine pouch, which is sometimes of considerable size. The adhesion of the peritoneum to the uterus is closest along the median line, and over the whole of the fundus, at which points its separation by dissection from the tissues beneath cannot" be effected without the aid of prolonged maceration ; but towards either side of the organ the connection is less inti- mate, so that here the membrane may be made to glide to a limited extent over the sub-lying structures. At the two upper uterine angles the peritoneum is continued on to the uterine appendages ; viz., the Fal- lopian tubes, round ligaments and ligaments of the ovaries. After sending off extensions to invest these parts, the portions of mem- brane which cover the anterior and posterior faces of the uterus respectively come nearly into apposition along the lateral borders of the organ (fig. 427.), where they are con- joined by a quantity of lax fibrous tissue, which serves to bind them loosely together, and at the same time to give support and protection to the numerous blood vessels entering the uterus on either side along the whole of this border. A similar portion of lax fibrous tissue serves to connect the anterior wall of the uterine cervix, where it is uncovered by peri- toneum with the posterior surface of the bladder, with which it lies in contact. The sectional views of the uterus in three directions already given serve to explain the whole of the relations of the outer or peri- toneal coat of the uterus to the muscular or proper coat. Fig. 426. shows the mode of attachment of this membrane to the anterior and posterior surface and fundus along the median line, and also the parts which are left uncovered by peritoneum. Commencing from the os uteri the vaginal portion of the cervix forming the anterior lip (a) receives an investment of mucous membrane as far as its point of at- tachment to the anterior wall of the vagina (v a). Beyond this the whole of the remain- ing portion of the anterior wall of the cervix, measuring above one inch in length (bb), is left uncovered either by mucous or serous membrane. At the termination of this space the peritoneum, reflected off from the bladder, reaches the uterus, and after investing the organ, is continued down to and beyond the fornix of the vagina (/). But at this point the mass of loose connective tissue before re- ferred to separates the peritoneum from the posterior cervical wall to a great extent (c), while finally a much larger portion of the cer- vix is contained within the vagina, posteriorly than anteriorly, and is consequently covered by mucous membrane(p), because the vaginal walls are attached at a much higher point here than anteriorly. Fig. 431. serves to exhibit the relations of the peritoneum to the fundus, and the absence of that membrane from the lateral borders of the uterus, while figs. 427. — 430. exhibit the relative proportions of the covered and un- covered parts as seen in a series of horizontal sections of different portions of the organ. The middle or smooth-muscular coat, upon which depends the remarkable firmness and solidity of the uterus, constitutes the prin- cipal bulk of the organ. This coat upon sec- tion appears of a pale pink colour, mottled with irregular white lines, and permeated by vessels which are particularly numerous near its lateral borders. The following are the compo- nent tissues of the middle uterine coat, viz. : — 1st. Smooth-muscular fibres. — These are found in every portion of this coat, and con- sist of fusiform fibres of the kind termed by Kolliker contractile fibre-cells, in which a single elongated oval nucleus may be occa- s s 4 632 sionally brought into view with difficulty. They all contain minute dark granules easily distinguished, and they sometimes exhibit upon their surface slight longitudinal folds or markings. These fibres have an average length of ToV an). 3. Amorphous or homogeneous connective tis- sue. — A considerable portion of connective tissue exists in certain parts of the uterus in the unformed state, constituting a transparent matrix in which the fibre-cells and nuclei are embedded, and by which they are so inti- mately united together, as to render their isolation, even with the aid of nitric acid, a work of great difficulty. The fibre-cells and nuclei which form the innermost laminae of the muscular coat, as well as the laminae themselves, appear to have scarcely any other connecting medium but this, especially in young subjects, while in the middle and outer- most laminae a large portion of fibrillated tissue is added, and the amorphous substance uniting the individual fibres into bundles is proportionally less in quantity. 4. Fibrillated connective tissue (white fibrous tissue). This, as just stated, is found chiefly among the middle and outer muscular laminae, serving here the purpose of a connecting me- dium between the several layers, and sup- porting the blood-vessels ramifying between them. The presence of this form of fibrous tissue is most readily exhibited by taking a thin perpendicular section from the outer muscular layer, and slightly drawing the la- minae asunder, after submitting the preparation to the action of acetic acid. The layers and bundles of muscular fibre, as shown in^/fg. 437., are then seen to be surrounded by, and im- bedded in, a quantity of white fibrous tissue which conceals the fibre-cells, and renders the distinguishing of them difficult. The fibres of this tissue have clear and sharp edges, appear to be of indefinite length, are independent of each other, and are clearly not mere foldings in an amorphous substance. Among them, however, and especially at the points where the laminae are separated, are seen numerous thin fl.it transparent bundles, marked by deep longitudinal wavy lines, to* which the above explanation of the cause of the appearance of wavy lines in this tissue which many physiologists have adopted might be more safely applied. Occasionally these wavy bundles exhibit an appearance of sharp curling lines, such as would indicate the inter- mixture of a small quantity of elastic tissue. 5. Elastic fibrous tissue. — The elastic form of fibrous tissue is also present in the uterus, as just stated, though not in great quantity. Besides the occasional presence of strongly curled fibres there may be seen in many places developed single fibres matted together, of the finer kind, commonh known as nucleus fibres; and also more abundantly the peculiar fusi- form formative cells from which these arise. I have frequently had the opportunity of tra- cing these peculiar dark-bordered cells in pro- cess of transformation into the finer elastic fibres, and so far of confirming those views whicii ascribe to this form of fibre a cell origin. These several tissues together with the uterine vessels and nerves, the former being in great quantity, make up the middle coat of the organ. And it is to the arrangement of these in laminae and bundles which are sepa- rated from each other, and perforated as it were in all directions by numerous vascular channels, that the mottled appearance of the unimpregnated uterus, as seen in sections, is due. The foregoing constituents of the middle uterine coat exist in different proportions in the body and neck of the organ respectively. In the body, notwithstanding the considerable amount of fibrous tissue by which the several component elements are connected together, the muscular fibre, either in its elementary or more developed condition, constitutes the UTERUS — (NORBIAL ANATOMY). largest portion, while in the cervix the fibrous element predominates, and the muscular fibre is proportionally less abundant. Course of the muscular fibres. — Regarding the precise plan of arrangement of the consti- tuent tissues of the middle uterine coat, and especially of its muscular element, in the unimpregnated state, numerous microscopic examinations have satisfied me that it is not possible to do more than to indicate these in a very general manner. Mme. Boivin at- tempted to describe the special course of the muscular fibres in the unimpregnated organ; but she appears to have abandoned the at- tempt a ter giving an account of what is seen upon the surfaee^of the organ when the peri- toneum has been stripped off after prolonged maceration. More recently the course of these fibres has been described by Kolliker, Gerlach, and others, in the deeper seated, as well as in the superficial layers. In investigating this part of the subject it appears to me that a sufficient distinction has not been made between the course of the in- dividual fibres, and the arrangement of the laminae or bundles into which they are col- lected, for these are by no means necessarily the same. According to my observations the contrac- tile fibre-cells are not distributed in equal pro- portions through all parts of the muscular coat, nor are they found everywhere in the same condition. It has been already stated, that no strict line of demarcation is discern- ible by the microscope between the three several coats, of which the uterus is said to consist. And this is particularly the case in respect of the muscular fibres which permeate all of them. In the so-called mucous mem- brane the muscular fibre-cells are loosely ar- ranged in an amorphous tissue, in which they lie embedded, intermixed with the elementary nuclear corpuscles, constituting their embry- onic condition. Here the fibre-cells form bundles, situated between the ramified canals or utncular glands of the uterus, and take a direction more or less oblique or perpendicular with regard to the inner uterine surface. But at the level of the base of the uterine follicles, where the proper muscular coat is considered to begin, and the mucous membrane to termi- nate, the contractile fibre-rells assume a dif- ferent direction and arrangement. Here at once they begin to exhibit a certain order of stratification, the strata being very closely su- perimposed, and arranged for the most part in such a manner as to lie parallel with the walls of the uterine cavity, which is therefore sur- rounded by them. These strata exhibit certain differences of composition and arrangement sufficient, for the sake of description at least, to justify an artificial division of them into three orders. The innerm >st of these may be termed the dense muscular strata. They commence im- mediately external to the mucous membrane, and extend outwardly through about half or two thirds of the thickness of the muscular coat. 633 When preparations that have been preserved in weak spirit, or those that have been finely injected, are examined by the naked eye, or with a hand lens, a peculiar mottled appear- ance is presented by sections of this part, Fig. 435. Thin section of a portion of the uterine walls, com- mencing from the peritoneum and extending inwards^ showing the irregular course of the strata of uterine fibre, and the divided vessels between them. (Ad Nat.) caused by the intermixture of numerous mi- nute white lines ramifying within a darker substance, and d viding it into a multitude of small lozenge-shaped spaces. The whiter lines mark the course of the finer uterine vessels, together with the bundles of white fibrous tissue which accompany them. The browner lozenge-shaped spaces consist of the fusiform contractile fibre- cells, united together by amorphous tissue into short bundles, which by their superposition constitute the lamina; just mentioned. When horizontal sections are made of this portion of the muscular coat, such as are represented in^/?g. 4-28., these bundles or strata are seen to be arranged in a concentric manner, forming interrupted circles surrounding the uterine cavity. But this ap- pearance must not be regarded as indicative of any corresponding direction of the muscu- lar fibre-cells, within these bundles or lami- nae, for all appearance of a concentric plan, as regards the fibres, at once vanishes under the use of the microscope. Fig. 436., representing a fine section taken from the inner muscular laminae, serves to exhibit the mode in which the contractile fibre-cells are arranged in this portion of the uterine walls. The individual fibres and em- bryonic corpuscles are imbedded in an amor- phous substance (the unformed connective tissue already described), by which they are aggregated together, so as to form bundles and laminae. In these strata the fibre-cells appear to remain distinct, and to be separated from each other by a distance not greater usually than their own diameters. 634- UTERUS AND ITS APPENDAGES. This is best shown in fine sections, pre- intermediate tissue to swell, the normal dis- viously prepared by acetic acid ; but it should tances between the cells may, to a certain be observed, that as this agent causes the extent, be thus artificially increased. The Fig. 436. Portion of uterine tissue from the internal muscular layers. (Ad Nat. x 150.) relation of the fibre-cells to the uniting ma- terial is most clearly exhibited in those parts of the preparation where the knife has divided the fibres transversely to their long axes. Here the relation of these two structures to each other may be exemplified by that of the harder and softer ingredients in certain por- tions of those geological formations termed conglomerate. At the points where the knife has cut the fibres obliquely, a corresponding change is observable in the outlines of the divided fibre- cells, which present in these bundles the figure of caudate cells, while in other places, where the course of the fibres has run paral- lel with the surface of the section, the fusi- form outline of the entire length of the fibre is distinguishable. All these varieties of direction are notice- able inj£g. 436., in a portion of uterine tissue not more than -£$" in diameter. The fibres which are here seen forming bundles and layers, run in some instances parallel with the surfaces of the laminae, and in other places spread out fan-shaped, or incline towards each other, like the component fibrillae of the penniform muscles. The bundles and layers of fibres are close-set and compact, and a comparatively small amount of developed or fibrillated connective tissue is found between or among these elements of the innermost strata of the muscular coat. The fibre-cells also are here apparently softer and more fleshy, and appear to be of newer formation than those forming the layers which lie nearer to the peritoneum. External to and surrounding these may be distinguished a second order of strata, among which the primary and secondary ramifica- tions of the principal uterine arteries and veins are freely distributed ; so that sections taken from this region do not present the same compact appearance as those from the inner layers, but are seen to be everywhere per- meated by vascular channels, which are par- ticularly conspicuous in the multiparous uterus. These numerous vessels, ramifying among the muscular fibres, make the course of the latter very irregular. When the section has been made* parallel with the broad liga- ment, the tortuous arteries, entering the uterine texture between the folds of the lat- ter, may be often traced to a considerable depth among the laminae ; while sections made in an opposite direction more frequently exhibit the gaping orifices of these vessels, and of the divided veins surrounded by lami- nae of muscular fibres, and of a more lax and fibrillated form of connective tissue, than is found among the inner strata. This inter- mixture of the larger uterine vessels with the muscular strata constitutes here a very cha- racteristic feature, and hence these middle strata may be distinguished as the vascular laminae of the muscular coat. External to these again lie a series of thin sheet-like laminae (fg. 437.), forming a tegu- mental stratum which does not entirely sur- round the organ, nor cover it in all its parts. It consists of 6 — 12 thin close-lying layers of fibres, whose course is parallel with the uterine surface ; the most external laminae UTERUS —(NORMAL ANATOMY). being inseparable from the peritoneum by which they are covered. These flat, thin, layers are continuous with and extended upon and into the broad and round ligaments, the Fallopian tubes, and the ligaments of the ovary, from which they spread out fan-shaped over the fundus and upper portion of the 635 anterior and posterior uterine walls ; meeting at length in a central perpendicular raphe, in which a few longitudinal bundles may be generally seen. These tegumental laminae are composed almost entirely of fusiform fibres, with very few embryonic corpuscles. They are united 437. Portion of uterine tissue from the external muscular layers close to the peritoneum. (Ad Nat. x 150.) together by a large proportion of strongly fibrillated connective tissue, which is, how- ever, sufficiently lax to permit a certain amount of artificial separation of the laminae. Within these laminae the fibre-cells are arranged in a manner somewhat different from that which characterises the internal strata. The amount of amorphous connecting matrix is here so small that the fibre-cells lie ap- parently in close apposition, their extremities interdigitating with each other, so as to form an imbricated pattern (Jig. 434.). These fibres do not so frequently change their course as the fibres of the innermost strata, but form a more continuous series ; so that sections of this part of the muscular coat are easily ob- tained, exhibiting the appearance of longitu- dinal strata, or bundles of fibre, such as are represented in Jig. 437. The course of the individual fibres within them is, however, traced with difficulty, on account of the large quantity of fibrillated connective tissue by which these layers are surrounded and con- joined. Immediately beneath the peritoneum all the constituents of the muscular coat are con- densed into a tissue which cannot be easily unravelled. Through this, however, nume- rous fibres may be seen to run in a direction more or less perpendicular to the surface, apparently for the purpose of connecting the peritoneum with the coat beneath. The mucous or deciduous coat ; Lining mem- brane of the cavity of the uterus. — This forms a moderately thick and soft layer which lines the entire cavity of the uterus, and is con- tinuous with the lining membrane of the Fallopian tubes, and of the cervical canal. On account of the large supply of capillary vessels which it receives, the mucous mem- brane is usually distinguished from the rest of the uterine parietes by its brighter red colour. It presents also to the unaided eye, when horizontal sections are examined, an appear- ance of being thrown into minute folds run- ning perpendicular to the uterine cavity (fig. 438.). These apparent foldings, however, are shown by a strong lens to consist of a series of ramified canals, which constitute the most remarkable peculiarity of this mem- brane. The proportionate thickness of the mucous membrane relatively to the rest of the uterine walls, though variable in respect of age and other circumstances, is usually about £th of their diameter. Its greatest thickness is found about the middle of the cavity, while towards the internal os uteri, and still more in the region of the fundus, the thickness is slightly diminished. To the unaided eye, the mucous membrane lining the body of the uterus, when viewed from the uterine cavity, is apparently smooth, or is seen to be perforated by minute aper- tures, but it rarely presents the appearance of deep folds or plicae such as are always found in the cavity of the cervix. Occasion- ally the surface is roughened and floculent from the exfoliation of its epithelial cover- 636 UTERUS AND ITS APPENDAGES. ing. The appearance of minute perforations is then lost, and a tomentose or apparently villous condition of the surface occasioned by the loosening out and partial detach- ment of the capillaries which freely ramify within this membrane is observed, \ The lining membrane of the uterus differs from mucous membranes in general in hav- ing no sub-mucous tissue, jso that it can- not, like that ot the intestines, be made to glide upon the sublying tissues, nor be dis- sected off from them so as to be displayed in a distinct layer. When very thin sections from spirit preparations are examined by transmitted light with a common lens, or with a low power of the microscope, the mu- cous is distinguishable from the muscular coat chiefly by its greater opacity and peculiar greyish colour, as well as by the numerous tortuous canals which permeate its substance, running chiefly in a direction perpendicular to the inner surface of the membrane, and strongly resembling in their general contour the cerebral convolutions Under the application of dilute acetic acid this comparative opacity and grey hue imme- diately disappear, and the tortuous canals alone serve to mark the boundary between the two coats. When an amplifying power sufficient to discriminate the component tis- sues is employed, the distinction between the two coats becomes still less apparent, because their constituent elements are then seen to pass from the one to the other by almost im- perceptible gradations, the difference between them being then shown to be morphological rather than structural, at least, at the points of their confluence. The mucous membrane lining the uterine cavity is composed of the following elements, besides the utricular glands, capillary vessels, and epithelium, viz., — free elementary cor- puscles or nuclei, contractile fibre-cells, and amorphous connective tissue. 1. Free elementary corpuscles or nuclei. — These are in all respects precisely similar to the elementary corpuscles already described as constituting apparently the embryonic state of the contractile fibre- cells in the muscular coat. They form in conjunction with the amorphous mutter the principal portion of the uterine lining membrane towards its inner surface. Here they are arranged in nearly close apposition, being imbedded in an amor- phous blastema, yet not so closely as to cause any mutual disturbance of their round or oval forms. 2. Fusiform fibres or contractile fibre-cells. — In the account which has been already- given of the muscular coat, the contractile fibres are described as existing in all the coats of the uterus. In the mucous membrane they are very abundant, especially towards the outer surface, or that part in which the mus- cular and mucous coats become conjoined, and where the transition from the one to the Other is almost imperceptible, and is chiefly observable on account of the difference in the arrangement of the constituent tissues of each. The fusiform fibres of the mucous membrane are gathered into loose bundles, united by amorphous tissue and intermixed with the elementary corpuscles from which they are developed. These bundles, the form of which is sometimes like the head of an arrow, are usually found between the utricular glands, pointing in a direction perpendicular to the uterine cavity. The individual fibres have here a softer, paler, and more fleshy aspect than in any other portion of the uterine coats ; they are apparently the youngest and most newly formed of the muscular fibres composing the uterus. 3. Amorphous connective tissue constitutes the chief bond of union between the several elements of the uterine mucous coat, and enters largely into the composition of the utricular glands. It presents no special cha- racter requiring a more particular description than has been already given of it in the ac- count of the muscular coat. Utricular glands or follicles. — These struc- tures, which were first more particularly- described by E. H. Weber and Professor Sharpey, constitute the most remarkable cha- racteristic of the uterine mucous membrane. By Reichert *, who has also investigated the subject, they were found present in every mammal which he had examined. The ute- rine glands or follicles consist of involutions or depressions of the mucous membrane, which are exceedingly numerous, and lie tolerably close together. They generally present the form of canals taking their course from the muscular walls of the uterus, through the sub- stance of trie parenchyma of the mucous membrane towards its free surface, where they terminate each in a separate orifice. In Ruminantia and Pachydermata they are large, and take a serpentine direction, so that they may be easily mistaken for vessels. By Burckhardt •)-, indeed, who has described them in the cow. they were termed vasa spiralia. Their spiral course is more obvious in the rodentia and carnivora. In the rabbit they are short and wide. The orifices by which the utricular glands terminate upon the surface of the mucous membrane are in some ani- mals large enough to be distinguished by the naked eye, as, for example, in ruminants, and occasionally in man ; but more frequently these require the aid of a lens for their detection. In the dog, two sorts of glands are de- scribed by Professor Sharpey |, simple and compound. The simple glands, which are the more numerous, are merely very short unbranched tubes closed at one end ; the compound glands have a long duct dividing * The composition of the mucous membrane of the uterus has been carefully investigated by Robin and Reichert; vide Robin, " Memoire pour servir a 1'Histoire Anat. et Path, de la Memb. Muqueuse Ute'rine ; Archiv. Gen. de IVIed. iv. serie, torn, xvii. ; Reichert, Ueber die Bildung der hinfalligen Haute; Muller's Archiv fiir Anat. Phys. 184S. t Observ. anat de Uteri Vaccini Fabrica. j Muller's Physiology, by Baly, 1837, p. 1574. I I KRUS — (NORMAL ANATOMY). into convoluted branches ; both open on the inner surface of the membrane by small round orifices, lined with epithelium, and set closely together. In man the form of the uterine follicles is by no means so definite as in the dog ; nor is it possible by any mode of dissection with which I am acquainted to isolate and display them separately.* They form in fact a sys- tem of tortuous canals ramifying in the .sub- stance of the mucous membrane, in which they seem as it were to be excavated. They are so closely set as apparently to possess no distinct boundary wall, but each canal is sepa- rated from those contiguous to it by a variable thickness of parenchyma, consisting chiefly of the elementary corpuscles and amorphous tis- sue just described, together with a certain ad- mixture of fibre-cells, usually found near the basal ends of the glands. No section that I have ever made has succeeded in exhibiting even a single gland divided longitudinally in such a way as to lay open the canal in its entire length, but every section made per- pendicular to the surface presents the same appearance of numerous close-set meandering canals laid open for short distances, and giving to the surfaces of the section an outline Fie. 438. Section of the entire thickness of the uterine mucous membrane (decidua) in the unimpregnated state, with a small portion of the muscular coat attached. The pale tortuous lines exhibit the course of the canals, termed uterine glands, the darker inter- mediate substance forms their walls. The finer lines are the capillaries of the mucous membrane injected. (Ad exactly resembling the cerebral convolu- tions. On account of this peculiarity it is difficult to determine whether these so-called glands consist of single isolated canals, or of a series communicating with each other. For the same reason it is also difficult to ascertain the precise mode of their termination towards the muscular coat, whether in a blind extremity in every case, as Weber represents them, o'r * It appears to me that the well-known repre- sentations of the human uterine glands by E. H- Weber (Zusatze zur Lehre vom Baue und d'en Ver- richt der Geschlechtsorgane, Taf. viii. f. 4, 5.) are too definite, and should be regarded rather as dia- grams than actual representations of what is seen in any mere section. Though it should be observed that these figures are taken from the pregnant uterus where the glands have enlarged and become more distinct. 637 whether by any indirect communication with the uterine vessels, which many considerations both physiological and pathological seem to point out as at least possible. The difficulties attending this part o^ the enquiry have been ably illustrated by Dr. Sharpey, and my own investigations fully confirm his statements upon this point. Nevertheless I have in many in- stances succeeded in di*tinctly observing the blind termination of these canals towards the muscular coat.* When sections of the mucous membrane are made parallel with, instead of perpendicular to, the surface, these canals are seen divided across. The appearance then presented is that of numerous round or oval apertures, which are more distinct in proportion as the section is made nearer to the uterine cavity. The uterine glands are lined by a fine den- tate epithelium, the cells of which are only slightly coherent at their margins. The orifices by which they terminate upon the surface of the uterine cavity vary in di- ameter from Ti"'' Fig. 442. ', and Uterus and appendages of an infant. a, cavity of the body laid open; b, of the cervix; c, anterior lip of the cervix; rf, left ovary opened; e, Fallopian tube ; /, right ovary ; g, internal os uteri, marking the division between the body and cervix. (Ad JTat.) and one or two gentle elevations diverging towards either Fallopian tube. These traces in the cavity of the body of its original con- struction out of two symmetrical halves, be- come generally lost after the uterus has been once impregnated, and indeed cannot always be distinctly seen in the nulliparous organ. One peculiarity in the form of the infantine uterus may be mentioned here, although it will be subsequently more particularly noticed. This consists in a curvature or inclination forwards of the upper part of the uterine body (fig. 467.). It is constantly more or less seen in infancy and childhood, and is usually partly retained in the virgin adult, but be- comes lost after one or two pregnancies. In an excessive degree, it constitutes the con- dition hereafter described as antiflexion of the uterus. From the time of birth to puberty, the com- ponent elements of the uterus remain nearly unchanged. They consist of granules and cells in various stages of development, from the round granular corpuscle to the elongated and ultimately fusiform fibre-cell ; the two latter being often drawn out, at their extremities, into long filiform threads. These are all imbedded in a semitransparent formless matrix, and dif- fer in no respect from the corresponding tissues in the adult, except that they are ge- T T 2 the body only 4/;/. These dimensions do not materially differ from those of the uterus in the first year of life, nor do they much exceed those of the same organ at birth. But as puberty approaches, the relative proportions of the cervix and body of the uterus are found to have changed, and the latter now preponderates over the former. For while the body now equals the cervix in length, the breadth of the former much exceeds that of the latter. The walls of the upper chamber now become thicker from the more rapid development of the uterine muscular fibre, which is their chief constituent. This not only increases the ex- ternal dimensions of the organ, but, at the same time, causes the parietes to become in- curved, and so to encroach upon the cavity contained by them, which, up to this period, preserves the form of a nearly equilateral triangle (fig. 442.), but now gradually acquires the slhape already described as characteristic of the cavity of the adult uterus (fig- 431.). The folds or plicae also (fig. 442.), which, in infantile life, are distinguishable upon the anterior and posterior walls of the cavity in the uterine body, resembling somewhat those in the cervical canal, gradually disappear ; their former situation being now indicated by only a slight groove or raphe in the median line, 644 UTERUS AND ITS APPENDAGES. nerally softer and less tenacious in proportion as they are younger. c. The uterus during menstrual life. — The average duration of menstrual life is thirty years. It occupies usually the interval be- tween the ages of fifteen and forty-five. The uterus in healthy women, throughout this en- tire epoch, is maintained in a state of perfect aptitude for the reproductive office, being, so to speak, under the control of the ovaries, with which it manifests so direct a sympathy, that every periodic change in the condition of the latter is, so far as the present state of our knowledge justifies the assertion, represented by a corresponding preparatory change in the former. But the menstrual phenomena being reserved for subsequent notice, it is only ne- cessary to remark here that the uterus under- goes usually a slight alteration in size about the time of each eatamenial flow, when its tissues are opened up, and become more spongy from the larger afflux of blood to them. The lining membrane appears to suffer a va- riable amount of disintegration. In the uterus of women who have died during menstruation, the interior may present a slightly roughened appearance in certain places, or this may ex- tend over the greater portion of the cavity. In women who menstruate painfully, it not infrequently happens that the entire uterine lining, to a greater or less depth, is exfoliated and discharged ; the process of expulsion being accompanied by much suffering and a greater escape of blood than occurs in ordi- nary menstruation. These dysmenorrhceal membranes (fig. 443.) present all the charac- Fig. 443. Portion of the lining membrane of the uterus cast off during painful menstruation. (Ad Nat.}* teristics of a true decidual structure, having upon their inner side, or that which had cor- responded with the uterine cavity, the fine cribriform surface occasioned by the orifices of numerous utricular glands, and upon the re- verse side the usual rough flocculent appear- * For this illustration Oldham. I am indebted to Dr. ance characteristic of the outer surface of membranes ordinarily discharged, along with the ovum, in abortion. In other respects, the uterus, throughout menstrual life, exhibits little or no alteration in form or bulk, but continues to present those characteristics of constant aptitude for its greatest and most important office, which have been explained in the description already given of the adult organ ; and these characteristics, if no pregnancy intervenes, it preserves until the period arrives at which menstruation, to- gether with the capacity for procreation, finally ceases. d. The uterus during gestation. The fully developed uterus. — The gravid uterus is only another term for the fully developed uterus ; for, although the latter designation is com- monly applied to the unimpregnated organ, when it has reached its ordinary size in the adult, the uterus does not attain the greatest amount of development of which it is nor- mally susceptible until the term of gestation is complete. The case of the uterus is perhaps in certain respects sui generis ; for it is the case of an organ which, having reached a certain period of growth, remains in a nearly passive con- dition, so far as mere growth is concerned, until a further amount of development is evoked by a new stimulus. There are, in- deed, two notable periods in the history of the development of the uterus, at which the in- fluence of such an additional stimulus is per- ceptible. For, first, as already shown, the uterus, like the mamma, remains without any material change from birth to puberty. The establish- ment of the latter condition is characterised by a correspondingly rapid evolution of both these organs. But the pubertal age may not arrive ; the individual may retain, in respect of reproductive capacity, the pre- pubertal con- dition ; and the uterus, in these cases, does not proceed beyond its first stage of develop- ment.* Again, the second stage, having been reached at puberty, may be continued through men- strual life, until, with the cessation of pro- creative power, the period of natural decline in the organ commences, and this is the con- dition which the part retains during the pe- riods or intervals when it is not employed in the process of reproduction, as well as through- out life in those cases in which it is never so employed. This degree of growth of the ute- rus is evoked by the full development of the ovary and the commencing discharge of ova, and is coexistent with the establishment of menstruation and the other conditions of pu- berty. But a third stage of development of the uterus is produced normally by the stimulus of impregnation, and partly by the growth of the ovum, and abnormally by the formation of * Compare >"# 405., representing the pre- pubertal uterus in a -woman agerl nineteen, with fig. 442., of the uterus of a child at three years. UTERUS— (DEVELOPMENT). any substance within the uterus, such as a polypus, which may cause distension of its walls ; or by the accumulation of fluid in its cavity, such as the menstrual fluid collected in cases of atresia or impsrforation of the vagina. The development of the uterus which is occasioned by the stimulus of pregnancy, takes place whether the impregnated ovum arrives within the uterine cavity or not ; although this does not occur in equal degrees in the two cases. In the case of extra-uterine preg- nancy, a very considerable thickening of the uterine substance usually takes place, together with a general enlargement of the entire organ, fully equal to that which is observed in the third month, and, in some cases, when gestation is not interrupted, even in the fourth month of ordinary pregnancy. In cases where gestation follows an ordi- nary course, the development of the uterus is such, that the weight, at the end of the period, is found to be increased about twenty-four- fold, and its length about five-fold. This development, as it affects the size, weight, form, and position of the entire organ, as well as the physical condition of its special parts, will now be considered. There is no example in man, and few in the animal kingdom generally, of a development of any organ or structure comparable in rapi- dity with that which takes place in the uterus during gestation, although the periodical growth of the deer's horn, and the formaiion of the placenta, may be quoted as in some respects analogous cases. Size. — The rate of increase of the uterus, during pregnancy, is subject to great varia- tions. But, with due allowance for these, which are dependent chiefly upon the size of the foetus and placenta, the quantity of liquor amnii, or the number of ova fertilised, an approximate estimate may be formed of the average alterations in size and bulk which the organ exhibits at different periods of normal gestation. These may be expressed in calendar months as follows : — RATE OF INCREASE IS SIZE OF THE GRAVID UTERUS ACCORDING TO MONTHS. Length. Breadth. End of 3 months 4£ — 5 inches 4 inches. 4 „ 5£— 6 „ 5 „ 5 „ 6 — 7 „ 5i „ G „ 7 „ 8—9 „ 10 „ i 8 „ 11 » 8 ., 9 „ 12 „ 9 „ The antero-posterior has usually an average of one inch less than the lateral diameter. Weight. — The weight of the gravid uterus, when fully developed, is most correctly ascer- tained in cases where death has taken place during, or soon after, labour at term. In twelve examples, estimated by Meckel, the 645 minimum weight was 2lbs., and the weight, relatively to the unimpregnated organ, was as 2-4 to' 1.* Form. — The form of the uterus undergoes many changes in the course of gestation. During the first three months, although there is a considerable increase of size, the primitive figure is retained with only slight alterations. After the third month, the body rapidly en- larging, while the cervix remains nearly un- altered, the figure of the former approaches that of a sphere. For the perpendicular and transverse diameters of the body then become nearly equal, and the only deviation from the spherical form is occasioned, first, by the cervix, which increases the vertical dia- meter of the entire organ by one inch ; and secondly, by the more tardy expansion of the body in the antero-posterior diameter, pro- ducing the form of a flattened sphere. After this, the perpendicular increasing more rapidly than the transverse diameter, and the upper segments widening faster than the lower ones, the uterus gradually acquires the ovoid figure which characterises it at the end of pregnancy. Alterations, nearly corresponding with these, take place in the cavity of the uterine body. The walls of this flattened triangular chamber begin to separate from each other ; and by their gradual expansion,, the angles and supe- rior and lateral lines, by which the cavity was at first bounded, are unfolded, so that the tri- angular is gradually exchanged for the pyri- form shape, and this again for the figure of a flattened sphere — as in the fourth and fifth months of gestation ; after which period the figure of the cavity corresponds very accu- rately with the general external form of the organ. During these alterations, the fundus be- comes strongly arched; while the sides un- dergo a slighter relative expansion, so that they exhibit only a gentle swelling ; but the anterior and posterior walls become curved and prominent — sometimes the former, and sometimes the latter, according to Dr. W. Hunter, showing the greater amount of con- vexity.f It has often been asked whether, during these changes, the walls of the uterus increase in thickness, or the contrary. In other words, whether the dilatation of the uterine cavity is to be regarded as a mere passive distension, with thinning of the walls; or whether the process of enlargement consists of an active excentric hypertrophy. In order to determine this point, Meckel examined the average thickness of the uterine walls at different periods of gestation. From observations which he had made in sixteen uteri, at all periods of gestation, he concluded that the walls increase a little in thickness in the beginning, but that this increase is not very considerable, and that towards the end of pregnancy they become gradually much * The estimates of Heschl, given at page 658., differ somewhat from these. f W. Hunter. An anatomical description of the human gravid uterus, page 5. T T 3 646 UTERUS AND ITS APPENDAGES. thinner. He found the thickness of the ute- rine walls, three weeks after conception, 6'"; Fig. 444. Human gravid uterus at eight months. The vessels have been injected, and the peritoneum removed from the sides and fore-part of the uterus. {After Wm. Hunter.) a, commencement of the cervix; bb, portion of the body corresponding with the brim of the pelvis ; cc, Fallopian tube concealing the ovary; dd, round ligament ; e, hypogastric artery, and /, vein ; g, spermatic artery, and h, vein. at the commencement of the third month, 5'" ; at the commencement of the fourth month, 4///. At the end of the fourth month, in two cases, 4/x/ ; in a third, %"' at the upper, and 4X// at the lower part ; in a fourth, 5'". At five months, in one case, 3'"; in another, 2"' superiorly, and 4"' inferiorly. At six and seven months, rather less than 3'" ; at eight months, in one case, 2///, and 2^'" ; and in another, 3"' above, and more than 4'" below. At nine months, they appear to be still rather thinner. In several uteri, which I have examined at all stages of gestation, I have found the thick- ness of the uterine walls exceedingly variable in different instances, even at corresponding periods of pregnancy, and particularly variable also in different parts of the same uterus.* According to my measurements, the extremes of thickness range from 2'" to 9"'. * This circumstance is remarkably exemplified in prep. No. 3605, in the Museum of the Koyal College of Surgeons, London. During these changes, which take place in ; the uterine body in the course of pregnancy, similar, but much slighter, alterations occur in the cervix. For the latter, being only the ex- cretory channel of the uterus, undergoes no further modification than is necessary to pre- pare it for transmitting the foetus when fully developed. Accordingly, in the early months of gestation, while the body is rapidly en- larging, the cervix undergoes but little change. Its tissues, however, become slightly expanded, so that the whole part is thicker, softer, and more elastic than in the virgin state. The margins of the os externum are consequently rendered more cushiony, and the orifice itself is enlarged. The canal of the cervix is also widened, and the palmse plicatae become un- folded, and project in the form of frill-like expansions (jtfg. 446.) ; while an unusual ac- tivity, occurring in the crypts and follicles, by which these parts are covered, a tough gelatinous secretion is poured out, which Fig. 445. Os and cervix uteri in the eighth month of pregnancy. The os is surrounded by a broad disc of enlarged cervical follicles filled with a gelatinous secretion. The os is represented as seen from the vagina, va, vaginal walls divided ; u, walls of uterus. Half the natural size. {Ad Nat.) collecting here in the form of a plug, assists in shutting out the uterine cavity and its contents from contact of external air and other influences. The increase in size of the os and cervix, which is gradually progressive through the whole of gestation, will be sufficiently ex- pressed by comparing the dimensions of these parts in their two extreme states. The virgin cervix measures usually at the base 7 — &f/f in its shorter, and 11 — 12"7 in its transverse dia- meter, and has an aperture of 3 — 4'" wide. It projects into the vagina to the extent of 4/// (fig. 425). At the end of pregnancy, the whole vaginal portion of the cervix would fill a circle of 1^" diameter ; the orifice measures transversely 10 — II"7; and that part which formerly projected into the fornix of the vagina, is now reduced nearly to the level of the vaginal walls. During these changes, it is often observed, especially in a first pregnancy, that, as gesta- tion advances, the projection of the cervix UTERUS— (DEVELOPMENT). uteri into the upper part of the vagina be- comes gradually less and less distinctly ascer- tainable by the finger. The latter change is commonly termed the "shortening of the cer- vix;" but the conditions upon which it de- pends, have not been very accurately examined, and they are certainly not at all clearly or adequately represented by the figures by which the description of this process is usu- ally accompanied. As much importance is usually attached, in works on forensic and obstetric medicine, to the changes in question, it will be necessary here to examine a little more closely the process by which this appa- rent shortening of the cervix is produced. It is commonly said that no material altera- tion, in the length of the cervix uteri, occurs before the fifth month of gestation ; that, at the sixth or seventh month, the uterine neck has begun to shorten ; at the eighth month, it is nearly, and at the end of the ninth month, it is quite, obliterated. But while it is true that a lessening of the projection of the cervix into the vagina com- monly takes place in pregnancy (fig. 446.), I can hardly coincide in the explanation which is usually offered of this circumstance, namely, that it is due to a gradual drawing up, as it were, of the cervix, by which its walls become added to those of the body of the uterus, for the purpose of increasing the capacity of the uterine cavity ; and that in this way the ute- rine neck is gradually shortened, until it finally disappears.* The accompanying fig. 446. exhibits the condition of the cervix in a woman aged thirty-seven, who, having previously borne children, died of phthisis in the eighth month of pregnancy. Here it will be perceived, that, without any actual diminution of the length of the cervix, which measured rather more than one inch, still there is no projection of it into the vagina ; but that it forms a flat roof to that canal in the mode which is usually described and explained as indicating the en- tire absorption of the uterine neck. The true explanation of this, as it appears to me, is, that the apparent shortening of the neck is caused not, at first, by any diminution of its actual length, but by an increase of its breadth, or its extension in the lateral direction, where- by the projection of the lips into the vagina is reduced to the smallest possible amount. The rest of the process, upon which the shorten- ing of the cervix depends, may be explained * See description of the figures in Gooch : "An account of some of the most important diseases peculiar to woman," p. 212 ; and Beck's Elements of Medical Jurisprudence, oth edit. p. 128. Regarding this explanation, which had been given by many preceding authors (see Mauriceau, torn. i. p. 97.; Smellie, vol. L p. 183. et seq.), but which Gooch was, I believe, the first to illustrate by dia- grams, it appears to me that much imagination has been exercised. The illustrations usually given are evidently diagrams supplied for the purpose of aiding the description of the process, as it has been supposed to occur, from examination of the part by the finger during life, but they give a very imperfect notion of the actual state of the cervix in pregnancy, as ascertained by dissection. 647 by the variable condition of the internal os uteri, or upper orifice of the cervix. If this remains unyielding until the time of labour, Fig. 446. Vertical section of the os and cervix uteri represented in the last figure. v, walls of vagina ; c, of cervix, and «, of uterine body. The cervical canal is nearly filled by the expanded palmae plicatse. Half the natural" size. (Ad Nat.) then the finger, on being placed within .the cervix, traverses the whole length of the canal before it reaches any part of the child ; and the general form and substance of the cervix being retained, the neck is said to be unob- literated. Such is usually the state of parts after repeated pregnancies. But if the in- ternal or upper os yields readily, as it usually does in the more advanced stage of a first pregnancy, then the head of the child gradu- ally settles down upon the lower orifice, press- ing aside the soft and yielding wall of the cervix, which thus forms for it a shallow, cup- like, or funnel-shaped recess, that may be so far said to be added to the uterine cavity ; and the finger, on passing within the os readily, touches the child, without having to traverse any length of cervix. When, therefore, the term, shortening of the uterine neck, is employed, it should be understood to imply that change which takes place from the hypertrophy and lateral exten- sion of the vaginal portion of the cervix, com- bined sometimes with a separation of the cer- vical walls from each other, occasioned by the descent of the head of the child ; the degree of this descent being regulated by the amount of yielding of the internal os uteri. But it does not signify any alteration in the anato- mical condition of the cervix and body of the uterus, which in every case retain their dis- tinctive characteristics to the end of preg- nancy : while the dilatation of the cervical canai is only an occasional occurrence, limited to the last stage of pregnancy, and having nothing to do with that apparent shortening which begins after the fifth month. Position actual and relative. — The enlarge- ment which the uterus undergoes during ges- tation, occasions of necessity very considerable alterations in its actual and relative position. On the occurrence of pregnancy, the organ, at first concealed within the pelvis, sinks, by its increased weight, lower than usual within that T T 4 648 UTERUS AND ITS APPENDAGES. cavity; and, pressing upon the bladder and rectum, occasions sometimes an irritable con- dition of these parts. But usually at the end of the third month, the fundus may be felt emerging from the pelvic cavity ; and in the course of the fourth month, it is always easily distinguishable in the lower part of the hypo- gastric region, having then risen to the height of about three fingers-breadth above the pelvic brim. In the fifth month, the hypogastric region is completely filled ; the abdomen then acquiring a considerable rotundity in this situ- ation. By the termination of the sixth month, the umbilical region also is filled, and the fundus uteri may be felt on a level with, or a little above, the navel. In the course of the remaining three months, the uterus rises gra- dually, until its fundus reaches the level of the ensifonn cartilage. And this is very nearly the limit of its ascent, though it occasionally, and chiefly in first pregnancies, rises slightly above that point. In women who have a roomy pelvis, and in those cases where the natural form of the uterus is not altered by over-distension nor mal- position of the foetus, there usually takes place, a few days or shortly before labour, a certain descent of the uterus, which has the effect of partially emptying the epigastric region, and relieving it from the pressure which it had sustained, especially during the last month. The direction which the uterus takes in rising from the pelvis into the abdominal ca- vity, is determined by various circumstances ; and it is interesting to observe in what way the addition of so large a body as the fully developed uterus to the already occupied ab- domen, is provided for, without any of the viscera suffering injurious pressure, and with- out that impediment to the circulating and respiratory systems, which, in the absence of such a provision, must inevitably take place. The oblique direction of the uterus, up- wards and forwards, is determined, firstly, by the corresponding obliquity of the pelvis, the plane of whose brim forms with the horizon an angle of 60°. But as the fundus gradually, after three months, emerges from the pelvic cavity, the oblique direction of the uterus is maintained by the symphysis pubis in front, and the sacral promontory behind. Between these, the superior portion of the uterus con- tinues to ascend, supported next by the abdo- minal walls anteriorly, and the spine poste- riorly. The intestines, being bound down by the mesentery, cannot be displaced, and will Fig. 447. Position of the uterus at the end of pregnancy. (After Maygrier.) UTERUS— (DEVELOPMENT). 649 therefore occupy a position midway between the spinal column and the posterior uterine wall. The pressure of the sacral promontory, and of the lumbar vertebrae, will still give to the uterus a forward tendency, which, on the other hand, will be prevented from becoming excessive by the elasticity of the front walls of the abdomen. If these have not been pre- viously much distended, the fundus glides upwards, and ultimately fills the epigastric hollow ; but if the abdominal walls have been much relaxed, as by frequent child-bearing, or if the pelvis is much deformed, the fundus uteri is usually turned directly forwards, or even downwards. At the end of pregnancy, the whole of the fore part of the abdomen is occupied by the uterus ; on either side lie the ascending and descending colon ; the transverse arch, to- gether with the omentum and stomach, fill the space between the fundus of the uterus and the diaphragm, while the rest of the abdomi- nal viscera lie laterally and posterity to its hinder wall. Thus it results, that in pregnancy, and espe- cially in its last stages, no injurious pressure is exercised, either upon the great vessels, the aorta and vena cava, or upon the intestines, liver, or stomach, whilst the descent of the diaphragm, and, consequently, the act of respiration, is not materially impeded, and space is left for the bladder and rectum to perform their appropriate acts. The situation and direction of the pregnant cervix, are necessarily affected by the increase of the principal organ, as well as by its con- tents. So long as the weight of the uterus causes it to descend lower into the pelvic cavity, as in the second and third months, the cervix is more readily reached, lying in the lower part of the hollow of the sacrum ; but when the greater part of the uterus lies, as it does at a more advanced period, above the pelvic brim, the cervix is felt with greater difficulty, being more withdrawn from the entrance of the vagina. If the lower segment of the uterus is more than usually spread out, as in transverse presentations, or in the case of twins, or of excessive distension by liquor amnii, then the cervix and os are drawn up so high as sometimes to be quite beyond the reach of an ordinary finger ; or, if the pelvis is very narrow, or the abdominal walls so lax as to cause the falling forward of the womb, the cervix will be equally beyond reach, and in these cases no part of the uterus can be said to be within the pelvic cavity. On the other hand, where the pelvis is unusually roomy, and the vagina and liga- ments are fax, the cervix may lie immediately upon the perineum, or even project beyond the orifice of the vulva. In most cases the cervix lies lowest in the pelvis at the earlier and latter periods of pregnancy, and highest about and after the time of quickening. Its projection into the vagina is not always in the direction of the median line, but is more often inclined to the left side, as that of the fundus is towards the right. This obliquity in the position of the uterus may be caused by an unequal length of the ligaments, or more com- monly by the projection of the lumbar verte- brae, which naturally gives to the body of the organ an inclination towards one or other side. Alterations in the special coats and tissues. — The Peritoneum is that coat which suffers the least alteration during pregnancy, yet the changes which it exhibits are not inconsider- able. They consist chiefly in a simple mul- tiplication of the component elements of the tissue, whereby it is enabled to keep pace with the enormous rate of growth of the uterus, so as still to invest all those portions which were covered by peritoneum in the un- impregnated state. During this process of growth, the membrane does not become at- tenuated, as would be the case if it suffered mere distension, but its thickness is rather increased, so that the addition of new matter must be in the aggregate very great. Dr. \V. Hunter imagined that this invest- ment of the gravid uterus was accomplished by an unfolding of the layers of the broad ligament, for he asserts that, " in proportion as the circumference of the uterus grows larger, the broad ligaments grow narrower, their posterior lamella covering the posterior surface, and their anterior lamella covering the anterior surface of the uterus itself." He arrived at this conclusion from observing the altered relative situation of the appendages, and their appearance of clinging to the sides of the uterus in advanced stages of pregnancy. But the latter circumstance is due to the arch- ing of the fundus, already described, which gives to the appendages a downward direction ; while that the broad ligament does not dis- appear, as Dr. Hunter asserts, may be shown by measuring the alae, or cutting them off, and comparing them with the SRU e parts in the unimpregnated state, when little or no difference in respect of dimensions will be found between them in the two conditions. Beneath the peritoneum of the gravid ute- rus is always found a large development of strong fibrous tissue, arranged in irregular cords and bundles. These sub-peritoneal fibres serve to strengthen the coats, and pro- bably greatly contribute to prevent rupture of the organ, especially during labour. The muscular or middle coat. — The tissues of which this coat is composed, together with their mode of arrangement in the unimpreg- nated uterus, have been already fully de- scribed. And it is to an increase of these, but especially of the vascular and muscular elements, that the enormous growth of the uterus during pregnancy is chiefly due. This growth consists partly in a greater develop- ment of the already existing structures, and partly in new formations. Ttie growth of the contractile fibre cells is here of especial interest. The elements of this tissue have been shown to consist, from infancy onwards, of fusiform fibre cells, inter- mixed with the round, oval, and elongated nu- constitute their embryonic 650 UTERUS AND ITS APPENDAGES. condition. These, up to the time of impregna- ments, whose terminations become inten- tion, form the special and sole elements of mingled with the adjacent cells. Fine lonei- the muscular tissue ; yet some physiologists tudinal markings are often distinguishable even of the present day refuse to recognise and some fibres exhibit an elongated nucleus' in these a muscular character, although it is The interior of the fibre is finely "ranular" and the margins show often a sinuous& outline! plain that the uterus so constructed has a contractile power. The occurrence of ab- ortion, sometimes at the very beginning of pregnancy, the expulsion of polypi and dys- menorrhoeal membranes, and the painful con- tractions termed uterine colic, prove that the unimpregnated uterus is so endowed. This non-recognition of a muscular character in the uterus before pregnancy has arisen from the minute size of the individual fibres, and from, the difficulty of explaining why these should grow to a given point, and then cease to be developed. But F. M. Kilian has given a happy illustration of this point, de- rived from the observation of Kolliker, that the contractile fibre cells which are found in the coats of the smaller blood-vessels, pre- serve a relative proportionate size to those of the larger ones, wherein they are more fully developed. So also the contractile fibre cells of the uterus proceed to a certain point of development in the unimpregnated organ, and there stop. And in this respect it makes little or no difference whether the organ exa- mined has been taken from an infant or an adult. But when pregnancy takes place, the fibres proceed to a further stage of development. Their growth is now so considerable, that the Fig. 448. Fibre cells of gravid uterus fully developed Wagner.} (.After to exhibit a muscular and fibrous elements of the gravid uterus are arranged in numerous thin lamellae, a good view of which may be obtained by cutting a thin slice perpendicu- larly out of the walls of the uterus at term. Fig. 449. The fibrous tissue uniting the several contractile fibre cells, instead of a length of ^S^LS^f. /^T ^ ^ ilicrea8e 0-002-0-003'", and width of 0'002'", in the considerably>..and towards the end of fifth month, present a length of 0-06—0-12'", and width of 0-0025— 0'006'", or even O'Ol'", and in the second half of the sixth month, a length of 0-1— 0'25'", a width of 0'004— 0-005"', and a thickness of 0-002 — 0-0028'"; consequently their length is increased from seven to eleven times, and their width from twice to five times.* But in addition to this greater development • of pre-existing fibre cells, a new formation of muscular fibre also takes place. This is ob- served, according to Kolliker, chiefly in the inner layers, although it may also occur in the external ones. The time of this new forma- tion is chiefly the first half of pregnancy, the earlier forms of the fibre cells being no longer discernible after the twenty-sixth week. From this time onwards, the muscular coat contains only colossal fibre cells. According to my observations, the indivi- dual fibre cells increase gradually in breadth throughout pregnancy, but their length is so variable, that the measurements just given can only be regarded as examples. The length, indeed, of the greater number of fibre cells after the third month cannot be determined with exactitude. A great many are thrown into numerous folds and contortions. Some exhibit transverse wrinkles, and the majority, when unbroken, end in long drawn out fila- * Kolliker, Manual of Human Histology, Svd. Soc. vol. ii. p. 259.; and Siebold and Kblliker's Zeitschrift, 1848, bd. I. p. 72. Section of the entire walls of the uterus after deli- very ; showing the arrangement of the lamince and the divided arteries and veins lying between them. (Ad Nat.}* By gentle traction, the laminae may be drawn partly asunder. They are then seen to be * In order to obtain a correct representation of the course of the laminae, I have here pinned out the preparation under spirit, and afterwards photo- graphed it for engraving, of the natural size. By the stretching, the breadth of the preparation is doubled, and the laminae are separated and rendered more distinct. UTERUS— (DEVELOPBIENT). most densely and closely united towards the inner and outer surfaces, but to be more easily separable in the centre or vascular layer, where the laminae are connected by a looser fibrous tissue, and are everywhere permeated by numerous large and small venous canals. These laminae are superimposed the one upon the other, in layers parallel with the two sur- faces of the uterine walls, but neither the laminae themselves, nor the fibres composing them, can be said to take any definite course. Within the laminae the fibres are arranged in flat bundles, which cross in all directions, as in the unimpregnated organ, but can seldom be traced in the same direction for any con- siderable distance. This is especially the case in the middle or vascular layer. In the superficial laminae, the tendency of the fibres is to converge towards the angles to which the appendages are attached, while internally an apparent disposition to the formation of concentric circles around the orifices of the Fallopian tubes has been sometimes observed upon inverting the organ after labour. But nothing like a continuous arrangement of muscular fibres in the form of circular or longitudinal bands surrounding or investing the organ, can anywhere be demonstrated by the aid of the microscope. The blood-vessels of the uterus undergo a marked increase in length, and especially in breadth, during pregnancy. The arteries pur- sue a remarkable spiral course whilst tra- versing the uterine walls. The veins form flattened channels between the muscular la- minae. The enlargement of the latter is ac- companied partly by a growth of the muscular fibre cells already existing in their tunica media before pregnancy, and partly by a trans- formation of their inner and outer coats. Kdlliker has observed, that in the fifth and sixth month, the fibres of the middle coat un- dergo an enlargement as considerable as those of the uterine walls, so that between these two scarcely any difference can be discerned. But besides these, both the inner coat, from the epithelium outwards, and the outer coat, acquire muscular fibres, which, except that they take a longitudinal direction, do not otherwise differ from those of the middle coat. This structure is found in the trunks of the uterine veins within the broad ligament, in the internal spermatics, and in all the veins of the uterine substances, which exceed 2'" in diameter. In the smaller veins the muscu- lar layer becomes less developed. Still, in those of £"' in diameter, a longitudinal layer of muscular fibre next the epithelium mav be found. The only exceptions consist of those veins which, in the placental region, penetrate the inner layers of the uterus, to become con- tinuous with the maternal veins of the pla- centa. These, notwithstanding their great width, instead of containing three, possess only one layer of muscular fibre, which, toge- ther with the epithelium, composes the entire coat of the vein.* * Siebold and Kblliker's Zeitschrift, foe. cit. p. 84. 651 Do the nerves of the uterus enlarge or mul- tiply during pregnancy? — This question, which once excited much controversy, has lost its chief physiological interest, since it has been determined that if any enlargement of the uterine nerves take place during pregnancy, this is nearly or entirely confined to the neurilemma, or fibrous nerve sheaths. Upon this point all observers are nearly or entirely agreed. Dr. Robert Lee states*, that whilst engaged in making dissections of the gravid uterus, he " discovered that the neunilemma was the constituent tissue of the ganglia and nerves which chiefly enlarged during preg- nancy." Dr. Hirschfeld remarks, " this in- crease of volume does not occur in the nervous tubules, but in the neurilemma." M. Jobert de Lamballe having traced the nerves of the uterus in man and animals, both in the unimpregnated and gravid state, says, that he " never observed any modification of their physical condition. They appeared more voluminous in consequence of an in- filtration of the cellular tissue which sur- rounds them, but they had not undergone any actual enlargement." Dr. Snow Beck removed the neurilemma, leaving only the bundles of nerve fibres or nerve tubules. On comparing the nerves of the gravid uterus with those of the unimpregnated organ, both dissections having been simi- larly conducted, he found that " the size of the nerves in both dissections is essentially the same ; and when the nerves are carefully compared, no doubt is left that the nerves of the gravid uterus have undergone no change in size, nor any change in position, except that consequent upon the development of the organ." But the neurilemma consists entirely of fibrous tissue, such as is common to most other parts of the body. It exhibits no struc- tures specially nervous. Its offices, in rela- tion to nerves and ganglia, are to support, protect, and bind together the nerve tubules and ganglionic nerve corpuscles. Now the real point of interest to be de- termined is, whether during pregnancy the innervation of the uterus is increased in any degree proportionate to the augmented supply of blood to the organ. But the neurilemma has never been regarded as either a generator * The Lancet, Xo. xvii. vol. ii. 1854, p. 349. Upon the subject of the nerves of the gravid uterus consult also, by the same author, " The Anatomy of the Nerves of the Uterus," 1841 ; " On the Nervous Ganglia of the Uterus," Philosophical Transactions, 1841, Part ii. p. 269. ; 1842, Part ii. p. 173. ; and 1846, Part ii. p. 211.; "Memoirs on the Ganglia and Nerves of the Uterus," 1849 ; and papers in the Lancet, vol. ii. 1854. Also the following: — Dr. Snow Beck, Philosophical Transactions, 1846, Part ii. p. 213. ; and Papers in the Lancet, vol. ii. 1856 ; Jobert de Lamballe, " Recherches sur la dis- position des Nerfs de 1'Uterus," Comptes Rendus, 1841, p. 882. ; F. M. Kilian, "Die Nerven des Ute- rus" ; Zeitschrift, fUr Rat. Med., Henle und Pfeufer, Bd.X. 1851; M. Hirschfeld, "Note sur les Nerfs de I'Ute'rus;" Gazette Me'dicale, Oct. 1852, No. 44.; C. F. J. Boullard, M.D., «* Quelques mots sur 1'Ute'- rus," 1853. 652 UTERUS AND ITS APPENDAGES. or conductor of nerve force, the former pro- perty belonging exclusively to the nerve centres, and the latter to the nerve tubes or nerve fibres. It is therefore necessary to as- certain if either nerve centres or nerve fibres become in any way multiplied or enlarged during the process of utero-gestation. Regarding a new formation of nerve centres, there is at present no anatomical proof that any fresh ganglionic corpuscles are formed during pregnancy within the ganglia or plexuses from which nerves proceed to the uterine tissues. Regarding the changes which take place in the nerve tubes or fibres during gestation, much interesting information is obtained from the researches of the late Dr. Franz M. Kilian, who devoted a considerable time to the in- vestigation of this point. Dr. Kilian dis- covered, that in the unimpregnated uterus a successive diminution of the nerve fibre, whether in bundles or isolated, takes place as it approaches the point of distribution. If broad, the fibre, after a certain portion of its course, begins to lose its greater breadth, dis- tinct double contour, and strongly marked granular contents, and then continuing as a pale fibre of intermediate size until it ap- proaches nearer to the uterus, it ultimately assumes an embryonic character ; that is, the extremely attenuated pale-margined fibre which traverses the tissues as a slender trans- parent band, has ceased to form a cylinder filled with nerve granules, and constitutes now only a pale slender stripe, or empty non- medullated sheath. Within this empty sheath there still occur, at distant intervals, little collections of granular fatty contents. Now, in the early periods of pregnancy these embryonal forms are observed to be- come gradually more distinct between the muscular fibres, and at a later period many of the fine tubes become filled with medulla, which was wanting in the unimpregnated con- dition ; the little collections of granular fatty contents just mentioned constituting the commencement of the nerve cylinders. For it is by the confluence of these isolated drops within the sheath that the medullated cylinder is formed, so that mednllated fibres not only proceed as far as the uterus, but also become developed with continually increasing dis- tinctness during pregnancy between the mus- cular fibres. These observations correspond exactly with changes which Kilian observed to take place also in j'oung animals, when the nerve fibres in the neighbourhood of the uterus are all in the embryonic condition, but become gradually medullated up to a certain point, in propor- tion as the development of the animal pro- ceeds, so that the nerves may be said to grow forward in the direction of the uterus. It should be understood, however, that in all these cases, the dimension of the nerve fibre never exceeds that of the branch whence it is derived, but that, on the contrary, a law of gradual diminution of the nerve is found to obtain in all cases, although the changes now described cause the rate of this to be different in the unimpregnated and gravid uterus respectively. Kilian had no opportunity of examining the condition of the nerves in the human uterus at different periods of pregnancy, but he doubts not that the alterations are analogous to those which he found in animals. The lining membrane of the uterus. Develop- ment of the decidua. — The last, and at the same time the most interesting, transforma- tion of the uterine tissues remains to be de- scribed. It is that which takes place in the lining membrane, and which has for its object the formation of an immediate covering and protection to the ovum. By the aid of this membrane, the fertilised ovum, on arriving loose in the uterine cavity, is re-attached to the parent body, and is enabled to receive from it the supplies necessary for nutrition and growth. But before the ovum enters the cavity of the uterus, the lining membrane of the latter swells and becomes softer and at the same time more vascular.* This augmentation in bulk of the uterine inner coat takes place in almost all cases when an ovum has been fer- tilised. That it does not depend upon the presence of the ovum in the uterus, is proved by the fact, that in cases of extra-uterine ges- tation, with rare exceptions, a development of decidua occurs within the uterus, forming there, in some cases, a more profuse growth even, relatively to the size of the uterus, than takes place in ordinary gestation. The phenomena which ensue immediately * In a paper on the Structure of the Placenta, by John Hunter, published in 1786 (Animal Eco- nomy), the decidua is described as composed of coagulable lymph. In another paper, 1794, on " the case of a young woman who poisoned herself in the first month of pregnancy," the pulpy substance lining the uterus, into which the blood-vessels of the uterus passed, and upon which they ramified, is stated to have consisted evidently of blood coagu- lated. The statements and descriptions in these two papers constitute the basis of the Hunterian hypo- thesis regarding the source of the decidua. But Dr. William Hunter had, even at that early period, a clearer perception of what the decidua really was, for in his posthumous work entitled "An Anato- mical Description of the Human Gravid Uterus," edited by Dr. M. Baillie in 1794, the decidua is de- scribed in the following phrases: — "This mem- brane is an efflorescence of the internal coat of the uterus itself." ..." It may be said to be the internal membrane of the uterus." ..." It is really the inter- nal lamella of the uterus." That the decidua con- stitutes simply a higher stage of development of the lining membrane of the unimpregnated uterus, in the same way that the muscular coat of the gra- vid organ is only a more advanced condition of the same coat before impregnation, is now proved be- yond question. Upon this subject consult, in addi- tion to the works quoted at p. C3t>., Sharpey, in " Miiller's Physiology, by Baly," 1837, p. 1574. ; Eschricht, " De Organis qua? Respirationi et Nutri- tion! Foetus Mammalium inserviunt," 1837 ; F. M. Kilian, " Die Structur des Uterus bei Thieren," in Henle and Pfeufer's Zeitschrift, bd. ix. ; Schroeder van der Kolk, " Waarnemingen over Het Maaksel van de Menschelijke Placenta;" and Coste, " His- toire Ge'ne'rale et Particuliere du De'veloppement des Corps Organises." UTERU S- (DEVELOPMENT). upon the arrival of the ovum within the ute- rine cavity are, in the human subject, as yet unknown. Direct observation of the earliest stages are still wanting, and, unfortunately, the difference between these first steps in the mammalia (except Quadrumana) and man is so considerable, that only a limited aid can be derived from comparative observation. The ovum, when first found in the human uterus, is lodged in a small closed cavity, forming a continuous structure with the decidua which lines the rest of the uterine walls. Jn this little chamber, which may be formed at any part, but is most frequently seen near one or other of the tubal orifices, the little spherical ovum lies loose and unattached. In various examples which have been preserved and , figured by different authors of the decidua at this stage, the size of this chamber varies from that of a pea to a hazel nut, and this size it acquires in the second week. The walls of the cavity containing the ovum, and those forming the lining membrane of the uterus, are nearly alike in appearance and texture. They both consist of decidua, the former constituting the decidua reflexa, the latter the decidua vera of Dr. W. Hunter. For greater distinctness, those names are sometimes exchanged for decidua chorii or oi-u/i, and decidua uteri. The latter, accord- ing to a suggestion of Dr. M. Baillie, is also occasionally termed parietal decidua. At this time all the uterine tissues have begun to expand and grow, and the uterine cavity, the walls of which were previously nearly in contact, to enlarge after the manner which in pathology constitutes eccentric hy- pertrophy. But, according to the foregoing description, this cavity now no longer forms one, but two compartments, the one partly inclosed within the other. Of these two chambers, the newly formed and smaller one contains and supports the ovum, and subsequently the foetus. It may therefore be termed the foetal chamber ; the other constitutes the original cavity of the uterus, and may be distinguished as the ute- rine chamber ; according to the views of Breschet, it is the hydroperionic cavity. As the foetal chamber enlarges, and the decidua reflexa becomes more expanded inconsequence of the growth of the contained ovum, it gra- dually encroaches upon and finally obliterates the uterine chamber, which can no longer be distinguished as a separate cavity after the fifth or sixth month of gestation. It \\ill be necessary to examine separately the general characters of these two decidual coats. That which lines the uterine cavity may be first noticed. The parietal decidua, at the very earliest period of pregnancy in which it can be examined, forms a soft and spongy layer, 1 — 2"' in thickness. That surface which looks towards the uterine cavity is ele- vated into numerous projections, which may be roughly compared to the cerebral convolu- tions, though relatively much Hatter and less regular than these ; between them are nume- rous little furrows or channels. The whole 653 surface, both in the sulci and elevations, is covered by numerous minute perforations, corresponding with those formerly described as the orifices of the uterine glands in the unimpregnated uterus. But these orifices, from being enlarged, may now be easily dis- tinguished by the unaided eye. They give to the surface a* fine cribriform aspect. All these characters are more or less observable also in the decidua lining the uterus, in cases of extra-uterine (tubal) gestation. Along the marginal lines formed by the angles of the cavity, where the decidua is always thinnest, these apertures are large and expanded, but in the elevated spots they are often closed, apparently from lateral pressure, occasioned by the rapid growth of structure. When early abortion takes place, the whole lining of the uterus, including the decidua reflexa, is often thrown off entire, forming a Fig. 450. Tlie entire decidua or lining membrane of the uterus cast off' in abortion. (After W. Hunter.) A portion of the specimen has been cut away to show the interior, which had formed the uterine cavity. The slight elevations upon this surface are very characteristic of the decidua in this condition. The outer surface is rough and flocculent. The foetal chamber is in process of formation in the upper part of this specimen, near one of the tubal orifices. The ovum having at this time no adhesion to the walls of the chamber, has dropped out of it. Bristles are introduced at the orifices corresponding with the Fallopian tubes, and pass out at the internal os uteri, the cervix not contributing to form the decidua. cast of the uterine cavity. If this occurs in the first fortnight of gestation, the mass re- tains the triangular form of the uterus. In each of the three angles is generally found an aperture corresponding with the points at which the membrane had been torn off from its continuity with the lining of the Fallopian tubes and cervix uteri. The outer, or dorsal surface of the sub- stance expelled, is always rugged. It exhibits numerous little papillary or club-shaped ele- 654 UTERUS AND ITS APPENDAGES. vations, and between these much smaller cup- like or conical depressions, which are seen by transmitted light to lead, where the membrane is thinnest, directly into the apertures ob- servable on the inner surface. At the thin- nest points of all, these apertures are so wide, and the cup-like depressions so shallow, that the part has the appearance of a net, the meshes of which still consist of the enlarged orifices of the utricular glands. Hence the epithet " lace-like," often applied to the de- cidua in this condition. The roughness of the dorsal surface of this, the parietal decidua, is occasioned by the membrane having been torn away from its connexion with the muscular coat of the uterus, in the act of abortion. The club-like projections are apparently the bases or blind ends of the hypertrophied utricular glands torn out entire from the substance in which they were previously embedded. When laid open, they are found to contain a small cavity. The cup-like depressions are the halves, or portions of similar, perhaps smaller glands, torn across, so as to leave other portions still attached to the uterus. The meshes are simply the orifices of such glands and of the channels leading to them. At this and subsequent stages thene may be often seen lying within and among these orifices, fine, thread-like ramified filaments, which some physiologists suppose to be utri- cular glands, or their epithelial lining, now becoming loosened out and falling away, — a view in which my own observations do not enable me to coincide. Seej%. 451. Fig. 451. seen, more or less distinctly, in the decidua throughout pregnancy, but are most conspi- cuous near the margins of the placenta. Fig. 452. External surface of the decidua vera, from an ovum of about two months ; showing the oblique channels in its substance. (After Schrceder van der Kolk.) a a a, filaments supposed to be the loosened utricu- lar glands (?) As pregnancy advances to the third and fourth months, the uterine chamber expands, the decidua which lines it increases in thick- ness in parts to 3 — 4'", and becomes at the same time more spongy, so that upon section it appears to be composed of flattened spaces or cells, communicating together by wide valvular orifices. These are best seen by examining under water the rough surface of an aborted ovum at that period, or the corresponding portion of the uterus from which it had been torn off. (Fig. 452.) These cells, or areolar spaces, continue to be Surface of the decidua vera more advanced. (After Schrceder van der A'oZ/i.) It is here represented as still attached to the walls of the uterus after the chorion, together with a layer of the decidua, have been peeled off from it. From a uterus at the sixth month of pregnancy, just beyond the margin of the placenta. The orifices and canals are much wider than in the first figure. They are still divisions of the same ramified canals, or uterine glands, which have been described as found everywhere in the lining membrane of the uterus before impregnation, fig. 438., but now become so dilated and tor- tuous as scarcely to be recognisable as the same structures.* In the latter months of pregnancy, the parietal decidua becomes thinner, and loses much of its spongy character, except imme- diately around the placenta, where this is still most distinct. It ultimately becomes blended with the outer surface of the foetal membranes, and is partly thrown off with them in the act of birth, while a part remains, form- ing a honeycomb layer, attached to the uterine muscular coat. If next the growth of the decidua reflexa, or decidua ovuli, be traced, this will be found to undergo a development corresponding with that of the ovum, which it encloses and pro- tects. The little chamber containing the ovum, which, as already stated, usually occu- pies a situation near one of the upper uterine angles (^g.450.), although it may also be found near the lower orifice ( Hunter, " Gravid Uterus," pi. 34., Jig. 4.), or elsewhere, appears at first like a small superadded cavity upon the outside of the larger one, or that formed by the parietal decidua. But as the development pro- ceeds, the foetal protrudes gradually into the uterine chamber, in the form of an incomplete sphere, whose upper pole rises free into the * The four figures 450, 451, 452, and 453., show- ing the decidua or lining membrane of the uterus in different stages of development during pregnancy, should be compared with figs. 438, 439. and 443., which exhibit the same structure in different con- ditions of the unimpregnated state. These struc- tures form a developmental series, the individual stages of which are often dislocated from their true and natural sequence by the employment of terms calculated to give an impression 'that the parts spoken of are different in structure and composition. " Mucous or lining membrane of the uterus," " L3'mph," and " Decidua," when so employed, should be read as convertible terms representing' the same part in different stages of development. UTERUS— (DEVELOPMENT). 655 uterine cavity, but the lower forms an attached pole of the little spherical chamber, which base of greater or less breadth, which is conti- have the appearance of apertures recently nuous in its entire circumference with the closed. Coste, in his beautiful series of illus- parietal decidua. The two chambers are trations*, directs attention, in several figures, totally distinct, and have no communication to a similar spot in the same situation, having with each other. In aborted specimens, an the appearance of a recently closed aperture, or umbilicus. These traces of openings in both the upper and lower poles of the sphere, are of consequence, in reference to the expla- nation which will be presently offered of the aperture may be sometimes seen in the base or outer surface of the foetal chamber, or that part which has been torn away from the ute- rine substance. In a very early specimen in my possession, and also in another which I have examined, one or more points are dis- tinguishable also upon the upper or northern mode of formation of the decidua reflexa and foetal chamber. The outer surface of this chamber is nearly Fig. 453. Uterus in the first month of gestation ; showing the formation oj the foetal cfiamber by the decidua reflexa^ more advanced than in fig. 450. (After Coste.) «, uterine walls laminated and traversed by numerous vessels; dv, decidua vera or developed lining membrane of the uterus, the uterine glands or canals being much enlarged ; d r, decidua reflexa, in which lies o, the ovum, at this stage often still unattached ; c, corpus luteum. smooth. Upon it, however, are seen the orifices of numerous uterine glands. These are usually wanting near the centre, or um- bilicus, but become more distinct towards the * Histoire Gene'rale et Particuliere du Developpe- ment des Corps Organises. 656 UTERUS AND ITS APPENDAGES. circumference, and are very numerous, large, and close set, in the decidual fold at the base, all round the line of apparent reflexion. Numerous flat vessels, obviously veins, terminating in minute subdivisions, are seen ramifying over the whole surface, but be- coming very scanty, or ceasing near the cen- tral point. They are continuations of similar vessels, which are still more conspicuous upon the parietal decidua. The capillaries in which these vessels terminate are exceed- ingly numerous, and may be sometimes seen deeply injected with blood. This is rendered the more conspicuous when the congestion is unequal, so as to form patches of a bright pink, alternating with other portions of a pale flesh colour. The internal surface of the foetal chamber, after the ovum has fallen out, or has been re- moved, presents a slightly uneven appearance, occasioned by numerous very shallow pits or depressions, occurring in close-set groups, and resembling, upon a small scale, the areolae upon the inner surface of the heart. When the body of the embryo begins to acquire length, the entire ovum exchanges the spherical for the slightly oval form, and to this the foetal chamber also becomes adapted. Such is found to be the form of the foetal chamber, sometimes in the latter half of the first, but generally during the second month, and from this period onwards the ovate figure prevails. In the latter part of the first month, or at latest in the beginning of the second, the ovum, previously lying loose in the foetal chamber, begins to be attached to the walls which sur- round it. This attachment is effected by the extremities of the villi, which from the first equally surround the chorion, everywhere be- coming attached to the little pits and anfrac- tuosities upon the inner surface of the foetal chamber just described. In this way the em- bryo, surrounded by its amnion and chorion, becomes securely anchored in the midst of .its little chamber, through the instrumentality of the villi, which, spreading in all directions, may be compared to the rays of the geometric spider's web. Thus to receive, to protect, and support the ovum, and to prevent its escape from the uterus, appears to be the first object of the formation by the reflected decidua of a sepa- rate foetal chamber (fig. 453.). Ultimately, as the ovum grows, the base of its chamber expands, and here takes place a more dense and rapid growth of decidua. This is the part commonly termed the decidua serotina. Here the chorion villi, which now form large ramified groups, attach themselves, and from the margins of the collections of sulci just described, into which the villi pene- trate, and which are now much extended, there proceed offsets or dissepiments of de- cidual structure. These dip down between the groups of villi sometimes as far as the surface of the chorion, and divide that which was formerly one continuous collec- tion of ramified chorion fringes, into the separate lobes which characterise the mature placenta. One or two points remain to be more ex- plicitly stated. It may be asked, how does the ovum gain the interior of the foetal cham- ber, or, in other words, how is the decidua reflexa formed around it ? In reply to this, little beyond conjecture can be offered. Of the numerous explanations which have been attempted, few are found to meet all the pe- culiarities of the case. It is most probable that either the ovum becomes embedded in some of those folds of decidua which are found in it at an early period of pregnancy, and so the decidua becomes built up around it, as Sharpey and Coste suppose. Or, as it appears to me more likely, the ovum, on first reaching the uterine cavity, drops into one of the orifices leading to the utrirular follicles, and in growing there draws around it the already formed, but soft and spongy decidua constituting the walls of the cavitv. The chief support for such a conjecture, beyond its apparent probability, is the fact ascertained by Bischoff, who, in one case in the guinea- pig, found the ovum in precisely this situation at the bottom of a uterine follicle.* The entrance of the ovum into the decidua being supposed, the rest of the growth of the reflexa is easily followed. The ovum now, in enlarging, raises the walls of the chamber, in which it lies, just as the skin becomes raised by the accumulating contents of a subcuta- neous abscess. The process is probably in part purely mechanical, and in part in the nature of an excentric hypertrophic growth ; for the actual substance of the chamber is much increased beyond the material of which it was at first composed. That some of this is borrowed from the parietal decidua, is very probable from the number of orifices of utri- cular glands seen upon its surface, which serve to show that the decidua reflexa is so far formed out of pre-existing structures ; but much is also due to the further development of the elemental decidual tissues ; and to the growth of these, the large vascular supply, which the reflexa at first receives, doubtless contributes. The little point, or umbilicus, observed sometimes at the upper pole of the foetal chamber, may mark the spot at which, upon either of the foregoing hypotheses, the ovum first entered the decidua. Another question which has never been satisfactorily determined, relates to the ulti- mate fate of the decidua reflexa. Dr. Hunter, from observing that, at the time of birth, only one layer of decidua can be found upon the secundines, supposed that, after a certain pe- riod of pregnancy, the decidua vera and re- flexa, having come into contact, united to form one membrane. Doubting this explana- tion, I have made many observations, with a view to settle this point ; and from these I * While these sheets are passing the press, I have received the last part of Otto Funke's " Lehrbuch der Physiologic," 1857, in which the same sugges- tion is offered, exemplified by the same case, which, indeed, is the only one yet known. UTERUS — (DEVELOPMENT). 657 am satisfied that no such union takes place ; but that, when the decidua reflexa has ful- filled the offices already assigned to it, and has ceased to be vascular, so that no further addition of material to it can take place, it becomes, after the fifth or sixth month, so completely attenuated by distension from the growth of the ovum within, that it is reduced to a mere film, of which the only trace left at, or indeed before, birth, is a narrow frill still discoverable at the margin of the placenta between the decidua vera and the chorion. But the decidua lining the uterine walls con- tinues vascular to the last ; and this alone constitutes the membrane a part of which at birth is found adherent to the outer surface of the chorion, and which Dr. Hunter, from ob- serving that it now consisted of only one layer, imagined was formed of the two de- ciduae united together. Histology of the decidua. — The morpholo- gical changes effected during pregnancy in the Fig. 454. Histology of the decidua. (After Schroeder van der Kolk.} A, orifice of utricular gland of an unimpregnated adult uterus surrounded by round epithelial cells ; B, cells of decidua in an ovum of about three weeks ; a, round and oval nucleated cells ; b, fat granula- tions ; c, cells, from a deeper layer, elongated and beginning to form fibres ; c, the same from an ovum of live weeks; a, round and oval cells, much en- larged, and containing nuclei and fat granulations from the surface ; b, elongated cells from a deeper layer ; D, orifice of a utricular gland from the same ovum, much enlarged as compared with A; E, margin of a valvular opening in a deeper layer of the decidua, from an ovum of two months ; at b, the cells have become elongated, at a they are tilled with fat granulations; F, long and broad cells from a decidua of nine months; a, the cells exhibit a nucleus, some having one and others two nucleoli ; b, three-pointed cell. Supp. decidua, and the chief purposes of these, hav- ing been stated, the histological peculiarities will now be briefly described. The lining membrane of the uterus, from infancy on- wards, is composed, as already shown, of free elementary corpuscles or nuclei, contractile fibre cells, amorphous tissue and epithelium, together with capillary vessels, and the tor- tuous canals termed uterine glands. These undergo important modifications, which serve to explain the great and rapid growth of the decidua during pregnancy. According to Schroeder van der Kolk, who has traced and figured with great care the several stages of development of these elemental tissues, the cells of the decidua, surrounding an ovum of about three weeks, situated nearest the villi, have already undergone considerable enlarge- ment. These occurred in the form of oval nucleated cells (fig. 454. B cr), with fine nuclei and fat granules, by intermixed ; while in the layer of the decidua, still deeper, oc- curred longer cells, that were already begin- ning to form fibres. In an ovum of five weeks, similar cells were found, in a further stage of development. Tn the superficial decidual layers, the oval cells, C a, were filled with granules, and contained a nucleus, and some a nucleolus. In the deeper layers, as before, the cells had become more elongated, C b. In and between all these cells were numerous minute fat granules, and among the cells lay fine nuclei. The openings of the utricular glands, D, which were surrounded by enlarged epithelial cells, were now considerably expanded, as compared with their usual condition previous to im- pregnation, A. At two months, the increase in size of the oval cells, E a, now abundantly furnished with fat granules, was still more marked. These were developed into long cells, b, which were found composing those valve-like membra- nous septa formed now everywhere on the deeper decidual layer, as already described,^. 452. From this period onwards, the development of the cells proceeds more and more rapidly, until those in the deeper layers become trans- formed into fibres, which it is impossible to distinguish, under the microscope, from the peculiar contractile fibre cells of the true mus- cular structure. In the ninth month are found colossal fibre cells, F a, which are rarely seen beyond the margin of the placenta. These were very transparent, and exhibited, some one, and some two, nucleoli. A remarkable three- pointed cell is sometimes also observed, F b. Fibres of fibrous tissue occur everywhere, and between them small cells and nuclei. The utricular glands have long ceased to be dis- cernible in the advanced stages of pregnancy. According to the observations, however, of Rolin, Robin, and Kilian, from the fourth or fifth month onwards, the decidua begins to lose the character of energetic life, which, up to that period, it had exhibited, and becomes atrophied, and less firmly adherent to the u u 658 UTERUS AND ITS APPENDAGES. uterine walls j while, between it and the mus- cular parietes, there appears a new formation of decidua, at first soft and delicate, but which gradually acquires the peculiar characteristics of that membrane. This layer is not thrown off at birth, nor dispersed in the lochia, but remains attached to the inner uterine surface, and forms the foundation of the new mucous membrane, with which, after labour, the ute- rus is furnished. M. Robin supposes that this new soft layer is often mistaken for a product of inflammation occurring in puer- peral and other uterine maladies. e. The uterus after parturition. Immediately after labour, the uterus, if entirely empty, occupies the whole of the pelvic cavity, together with the lower portion of the hypogastric region. The bulk of the organ varies in different individuals, and is considerably greater after twin or multiple pregnancy. The tissues generally are of a redder colour, and softer, and more easily lacerable than in the unimpregnated condition ; those of the cervix being usually more lax than those of the body, from infiltration of serum, and oc- casionally, in parts, of blood. The cervical mucous membrane, which is retained*, after labour exhibits here and there sometimes slight lacerations, extending occa- sionally into, or through, the proper tissue of the part. In other respects, the internal aspect of the cervical canal resembles that of the same part in the last month of gestation, ex- cept that the large and voluminous plica? (Jig. 446.) have become folded out and flattened during the previous act of labour. Around the margin of the internal os uteri may be seen a thin ragged fringe marking the point from which the decidua, here usually much attenuated, had been torn away. The entire uterine cavity is denuded ; it presents everywhere, except at the placental space, a rough, flocculent, and sometimes honeycomb-like surface, caused by the de- tachment of a portion of the decidua and its discharge along with the foetal membranes. Another portion remains covering the mus- cular structure of the uterus, but is in parts so thin, that the latter appears to be left nearly bare. The surface to which the placenta had been attached forms usually one-third of the entire inner superficies of the contracted uterus. This, which is termed the placental space, is easily distinguished by its uneven, rugged, and somewhat nodulated appearance; caused chiefly by the presence of numerous large veins, whose truncated orifices obstructed by coagula here protrude slightly above the general level. Upon section, the uterine walls exhibit everywhere the same laminated arrangement of the proper tissues, with numerous inter- mediately lying tortuous arteries and flat- * For the discussion of this question, see the works of Heschl, Robin, and Kilian, hereafter quoted. tened veins and sinuses, already described as observable in the uterus during the latter pe- riods of pregnancy (fig. 449.). These flattened thin-walled veins are usu- ally empty, or contain a few unadherent coa- gula. Those, however, which occupy the seat of attachment of the placenta, where they are much larger than in any other situation, are filled with dark or greyish-red clots adherent to their walls, and closing their mouths, which terminate directly upon the uterine cavity. The peritoneal coat of the recently emptied uterus is of a pale pinkish-white colour, and presents a smooth, shining, and in parts a slightly wrinkled surface. It is thicker and less diaphanous than the same membrane be- fore labour. The process of involution. — No rapid or material alteration in the size or composition of the organ occurs during the first few days after labour. In the course of the first week, however, commences .a series of important and interesting processes, continued during the greater portion of the two months imme- diately following labour, and having for their object the restoration of the uterus to a con- dition similar to, though not identical with, its state before impregnation. These changes consist in a gradual diminution in the weight and dimensions of the organ accompanied by a corresponding metamorphosis and ultimate reconstruction of its tissues. They together constitute the process commonly termed the involution of the uterus, which will now be examined. Changes in dimensions and 'weight. — Accord- ing to repeated estimates made by Heschl, the weight of the uterus, immediately after labour, ranges from lib. 6 — 7oz., ordinarily, to 2lbs. 5 — 7oz.; the latter being the weight after twin labour. The dimensions depend upon the degree of contraction. Under ordinary circumstances, the entire length is 8 — 10 inches, and the thickness of the parietes 1 inch. These first changes in the dimensions of the organ, as compared with the state previous to labour, are effected solely by the contraction of the uterine fibre. They consist chiefly in a re- arrangement of relative position in the com- ponent tissues, by which, while the entire substance of the uterus remains undiminished, its length and breadth are greatly reduced, and the thickness of the parietes correspondingly increased. In one respect, however, the en- tire bulk* and weight are less than they were before labour, because a much smaller quan- tity of blood now circulates in the walls, but the solids remain unaltered. At the end of the first week, the diminution of the organ is not very considerable. Its weight is merely reduced from 1 Ib. 6 — 7 oz. to lib. 3 — 4oz. At the end of the second week, the rate of diminution is found to have been much more rapid ; the organ now weighs only 10 — 1 loz. At the end of the fifth week, 5 — 6oz.; and in the course of the second month, it is reduced to its ordinary weight of 1£ to 2£oz. j but it never entirely regains the UTERUS — (DEVELOPMENT). small size and dimensions characteristic of the virgin state. Metamorphosis and restoration of the com- ponent tissues. — The first and immediate re- duction in size of the uterus, after parturition, has been just stated to depend upon mere contraction of the uterine fibre. But con- traction alone will not account for those great and remarkable reductions in the dimensions of the organ which have been just described. The true explanation of these phenomena is furnished by a series of metamorphoses affect- ing more or less the entire uterine tissues, by which the greater portion of those structures which have been formed during pregnancy, become disintegrated and removed, while other and new tissues are developed in their place.* In these metamorphoses, the colossal fibre cells, which form the great bulk of the newly added material, play the most important part. These have been traced, during their develop- ment in pregnancy, from the small fusiform cell of the unimpregnated uterus to the fully formed fibre of the organ at term. The growth of these proceeds part passu with that of the foatus, for whose expulsion they are destined ; and this act being accomplished, their de- struction and removal becomes a necessary prelude to the recomposition of the entire organ upon the same type as before impreg- nation. In this respect, the aggregate forma- tion of fibre cell is comparable to the deer's horn, the placenta and other structures which, having served the purpose of their formation, and being incapable of suffering retrogression, become caducous, with this difference, how- ever, that the one class of structure being thrown off in a mass, the act of separation is striking and obvious ; while the deciduous process in the other is gradual and fragmental, and can only be discovered by the most pa- tient and careful scrutiny. The disintegration and removal of the ute- rine muscular fibre is effected, first, by the transformation of each fibre into molecular fat. This process does not commence earlier than the fourth or sixth day after labour, and not later than the eighth day. Certain dif- ferences are observable in the order of retro- gression. Thus the process begins somewhat later in the inner than in the outer lamina?, while the cervix remains unchanged a few days longer than the body. In the individual fibres, the process of decay begins at many points simultaneously. The fibres lose their sinuous outline, and become paler; while within them appear yellow oil granules, commonly arranged in rows. The nucleus of the fibre is pale, but distinct, until it becomes obscured by the increase of the oil granules ; while the extremities of the cells, on account * On this subject the following ma}' be consulted with advantage: — Dr. R. Heschl, " Untersuchun- gen iiber das Verhalten des menschlichen Uterus nach der Geburt," in the Zeitschrift der kais. kon. Gesellschaft der Aerzte zu Wien. 1852. B. ii. p. 228. ; F. M. Kilian, " Die Structur des Uterus bei Thieren," loc. cit. ; Schroeder van der Kolk, loc, cit. 659 of their tenuity, are the first to suffer disin- tegration. Fig. 455. Process of involution or disintegration, and renewal of the uterine fibre after parturition. (After Heschl.} a, the old fibres filled with fat granulations 2 — 4 weeks after delivery; b, development of new fibres in different stages, about the fourth week. During the second and third week, the process of disintegration continues ; arid it is probable that a considerable absorption of effete material now takes place, since it is not easy to explain otherwise that rapid diminu- tion in bulk, especially in the second week, which the entire organ undergoes, as shown by the calculation of weights already given. As a result of these molecular changes, the uterus now loses its reddish colour, and be- comes of a dirty yellow, and is at the same time more easily lacerable. In the course of the; fourth week, and pos- sibly sometimes during the third, there ap- pears, in the midst of the now degenerated fibres, the first traces of a new formation of uterine substance. These occur first in the form of cell nuclei, which are concurrently developed at several points ; and gradually, while the last portions of the old muscular coat are being disintegrated and absorbed, acquire the character of the new muscular fibre cells (fig. 455. b). So that, by the end of the second month, the reconstruction of this portion of the uterine substance is often com- plete. The disintegration of the remains of the decidua, and the reconstruction of the lining membrane of the uterus, which had been re- moved during the act of birth, is effected by a process very similar to that just described. With regard, first, to that portion of the inner uterine superficies, which had been co- vered by the placenta, it is observed that this undergoes a somewhat slow retrogression. The veins, filled by thick clots in the normal state in consequence of the progressive invo- lution of the intermediate uterine substance, occasion here a marked protrusion ; so that very often, after four or six weeks, the pla- cental space forms an elevated spot of twice u u 2 660 UTERUS AND ITS APPENDAGES. the circumference of a dollar. Finally, how- ever, these coagula are removed, and, together with the veins, disappear, while the place sinks to the level of the surrounding parts ; and, after becoming smooth and receiving an in- vestment of mucous membrane, is generally no longer discernible. The restoration of the placental space to its former condition does not, however, always proceed normally. Sometimes, in consequence of excessive acti- vity in the process of reconstruction, hyper- trophic growths of the new material take place ; so that, several months after labour, a tumour of more or less considerable size, formed at the expense of the uterine tissues, is found to occupy the original seat of the placenta. I have satisfied myself by several microscopic examinations of the correctness of Heschl's opinion, that in this way are formed some of those anomalous-looking fleshy substances which are occasionally dis- charged from the uterus, and are regarded as moles. The hittological changes, which take place after labour in the tissues lying internally to the muscular coat, up to the complete resto- ration of the mucous membrane, have been examined by many observers, not always, however, with corresponding results. It ap- pears certain that a portion at least of that layer of decidua which is still left attached to the uterine walls, is removed by fatty trans- formation, and that many of the products are discharged by the lochia. Schroeder van der Kolk has traced this process as it occurs in the nuclear cells and fibres, which form so large a portion of the decidua. Those very broad fibre cells, which are visible in it up to the ninth month of pregnancy, are no longer to be found four or five days after labour, when they appear to be transformed into long cells, through an abundant fatty transforma- tion which progressively continues, until, by the increasing development of the oil granules and the corresponding diminution of the cells and fibres, the situation of the latter can ulti- mately only be discovered by the still existing longitudinal direction of the fat nuclei, while all traces of a cell wall have entirely disap- peared. Without the aid of the microscope, how- ever, it may be seen that, a few days after labour, the entire inner surface of the uterus is covered by a more or less red soft pulpy substance, which has the same anatomical composition as the decidua. This, which is considered by some physiologists as identical with the layer of decidua already described, as formed, according to Kilian, Robin, and others, as early as the fourth or fifth month of gestation, is not discharged after labour, but becomes the seat of that reparatory pro- cess, by which the restoration of the mucous membrane upon the uterine body is effected. Between the twentieth and thirtieth day, this layer begins to resume the character of a mu- cous membrane. It is at first more pulpy, and softer, and thicker than mucous membrane in a normal state. The vessels become distinct in it about the third week, and sometimes still later. Previous to this, the blood appears to be contained in simple channels between the elongating cells. The epithelium is as yet hardly formed. By scraping the inner surface of the uterus twenty days after labour, Schrceder found still only the remains of half decomposed cells. But no new cells with cilia could be yet with certainty discovered. The utricular glands make their appearance last of all. In several cases, Heschl found them completely formed at the end of the second month ; but previous to this, their de- velopment could not be traced.* Finally, it may be said that the restoration of the mucous membrane, with all its peculiar structures, is completed about the sixtieth or seventieth day after delivery, i. e. by the time that the uterus is reduced to its normal bulk. Thus it appears, that the act of involution consists in two processes, which are concur- rently performed, yet with opposite purposes. For the act of reconstruction being com- menced long before the retrograde metamor- phosis is complete, the result of both is, that a restitution or reconstruction of certain tis- sues of the uterus, more or less complete, takes place. With regard to the muscular coat, it is perhaps not any overstatement of the fact to say that each ovum is provided with its own series of fibres for the purpose of effecting its expulsion, and that these, after parturition, entirely disappear, or at least can no longer be recognised, while a new series of embryo- nic or undeveloped forms appears in their place. The same may also be said of the decidua, though with certain differences as to the time and mode of its destruction and re- novation. Regarding the fibrous tissue of the uterus, little has been determined with accu- racy ; but enough has been observed to ren- der it probable that this also, to a certain extent, becomes subject to fatty transforma- tion. The blood-vessels appear to be likewise partly involved in a similar process, although their principal trunks probably suffer but little change beyond a material diminution of size. The peritoneum is that tissue which undergoes the least apparent alteration. It preserves, however, a thickness proportionate to the reduced bulk of the organ, and consequently it must suffer a corresponding involution. Regarding the puerperal alterations in the nervous system of the human uterus, but little is known. Kilian-}-, after examining a spe- cimen at eight, and another at twelve days after labour, as well as the uterus of many animals at different periods, arrived at no de- finite conclusions. He thinks it in the highest degree doubtful, that, in the puerperal state, the nerve fibres undergo the same involution process as the other tissues ; viz. that the old fibres are entirely destroyed, and become replaced by a new, younger, or embryonal * By Kilian they are said to be formed during pregnancy, f Loc. cit. UTERUS — (DEVELOPMENT). form. He rather conceives that a reduction so takes place, that either the contents of the nerve fibre are partly or entirely removed by resorption, so that there remains, according to circumstances, a partly or entirely empty sheath ; or that the contents of the fibre are transformed in the same manner that Gilnther and Schon (Henle, Allgemeine Anat. p. 771.) observed in divided nerves ; viz. that the contents of the tubules become coagulated, as after death, and are then subject to resorption: the fibre appearing then to be perishing, and ribbon-like, and the contents to be disappear- ing. Regarding the human uterus, he thinks it in the highest degree probable, that the nerve fibre is included in the energetic resorp- tion process that affects the puerperal uterus generally ; that a reduction of the fibre fol- lows; and that, in the next pregnancy, it again becomes developed pan passu with the development of the other tissues. /. The uterus after the menstrual epoch, and 661 in old age. — Whether the uterus has been employed, in its ultimate office, in the pro- cess of reproduction, viz. that of gestation, or whether it has proceeded only so far towards this as to have been limited to the repetition, in unvarying succession, of that preparatory stage which is expressed by the minor func- tion of menstruation, in either case the period equally arrives at which the activity of the organ passes away. Ova are no longer dis- charged from the ovaries. These cease to be creative or developing organs ; and with this cessation of the proper function of the ovary, there comes also a corresponding diminution, and finally a termination of the correlative offices of the uterus. It is now interesting to observe how the uterus gradually resumes some of the pecu- liar features which it exhibited at an earlier period of life.- It may be said to fall back again into its infantine condition. For with the shrivelling of the ovaries, and their reduc- Fig. 456. The uterus in old age; showing a return to the infantine proportions between die body and cervix. o, the shrivelled ovaries. This figure exhibits the parts of half the natural size. (Ad Nat.) tion to a size as small sometimes as that of a child of two or three years, (J%. 456.) the ute- rus also gradually shrinks, not in all its parts, but principally in the body, or that portion which is chiefly employed in the processes of menstruation and gestation. This part be- comes atrophied more than the rest ; its walls become thinner, partly from diminished circulation in them, and partly from atrophy of the component tissues, which appear pale and nearly bloodless. Thus it happens that, in advanced life, the walls of the uterine body, no longer possessing that fulness which at an earlier period caused them to encroach upon thecavity,and to exhibit that incurvation of the sides and fundus which has been described as characteristic of the mature organ, again re- turn to the straight and more attenuated con- dition which they had in early life. We mav often observe, therefore, in the uterus of aged persons, a nearer approach to the form of the equilateral triangle, caused by the short- ening of the body and the straightening of its walls, than is seen in the uterine cavity of mid- life ; and it is this return to the form of the foetal cavity, together with the now prepon- derating size of the cervix, which remains Fig. 457. Thinning of the uterine walls in old age, and return to the triangular form of the cavity characteristic of the infantine (fig. 442.) and undeveloped uterus (fig. 465). (Ad Nat. Half the natural size.] nearly unchanged, that gives to the aged ute- rus its greatest similitude to that of infancy or early youth. u u 3 662 UTERUS AND ITS APPENDAGES. But these changes are not limited to the body of the uterus. The external uterine orifice being now no longer required to serve as a conduit for fluids to or from the uterus, or for the passage of more solid contents, becomes reduced in diameter, and may some- times be observed to possess an aperture that would hardly admit the head of a mo- derate sized probe. Fig. 458. Os uteri in old age. {Ad Nat.) FUNCTIONS OF THE UTERUS. The uterus, in common with the rest of the generative organs, being concerned only in the reproduction of the species, its offices are limited to that period in which the animal functions are maintained in their highest state of efficiency. The growth of the body is nearly or quite completed before the sexual offices commence, and the power of reproduction continues as long as the frame is maintained in full vigour ; but when the age arrives at which the animal func- tions generally begin to decline, their de- cay is anticipated by the total cessation of the power of procreation in the female. The period, therefore, is limited, yet not brief, during which the functions of the uterus can be exercised, and on either side of this epoch the organ remains passive, except under ab- normal states. The chief functions of the uterus are those which relate to — 1. Menstruation; 2. In- semination ; 3. Gestation ; 4. Parturition. The office of the uterus in menstruation. — Although the uterus is the efficient instrument in the performance of menstruation, yet the power of initiating and regulating this function resides in the ovaries, which exert a powerful reflex influence, not only upon the uterus, but also upon the entire organism. Without the ovaries, menstruation has never been known to occur. Their artificial removal is followed by a permanent cessation of the catamenial flow, although the uterus may be left unin- jured ; while the congenital absence of both ovaries is always accompanied by an enduring amenorrhoea. The external sign or evidence of menstrua- tion consists in the occurrence of a sanguine- ous discharge, which escapes from the vaginal orifice of women in health, periodically, except during pregnancy and lactation. This dis- charge first appears usually between the four- teenth and sixteenth years, and continues to be repeated at intervals of a lunar month for an average period of thirty years. The time, however, of the commencement, as well as of the decline, of menstruation is very variable, and may be either much accelerated or re- tarded, according to individual peculiarities.* Periods of duration and recurrence. — The catamenial period and interval together occupy a space of one lunar month. And in some women this function is performed with such regularity that the day, and very nearly the hour, of its expected return may be predicted. The natural duration of the flow varies from three to five or even seven days. An interval then occurs during which the flow entirely ceases. This occupies from twenty-one to twenty-five days; and it is during the first half of this interval that conception most com- monly takes place. It cannot, however, be asserted that this degree of regularity is observed even in the majority of women. Frequently the period of regular return is anticipated by one or more days ; or, on the other hand, it may be re- tarded, without the occurrence of any con- comitant disturbance of other functions, such as would justify the regarding of these ex- amples as abnormal. But whatever may be the amount of variation — dependent in most cases upon idiosyncrasy, — still a law of pe- riodicity is observed which, in all ages and countries, has been recognised, and more or less distinctly expressed by such terms as catamenia, menses, courses, periods, regies, mois, monatlicher Fluss, and the like. No catamenial discharge takes place nor- mally during pregnancy or lactation. Excep- tions to both these rules, however, occur, and instances of the latter are sufficiently common. But with regard to the former, it is probable that many at least of the recorded cases of menstruation during pregnancy have been cases in which the placenta was implanted low down, or even over the os, under which circumstances it is well known that slight flooding will occasionally commence at an early period of gestation, and observe a cer- tain rough periodicity. Upon anatomical grounds, a catamenial flux during pregnancy can only be supposed possible where the con- dition of the uterus is such as to admit of the discharge taking place from the vaginal portion of the cervix ; an occurrence which is shown by Mr. Whitehead to have obtained in all the instances of supposed menstruation during pregnancy which he had investigated. For " on examining these cases with the speculum * For much valuable statistical information re- lating to the periods of invasion and decline of the catamenia, and in refutation of the popular belief that these periods are greatly influenced by climate, &c., see Robertson's Essays and Notes on the Pl^si- ology and Diseases of Women ; also, on the subject of menstruation generally, Whitehead, the Causes and Treatment of Abortion and Sterility; A. Brierre de Boismont, De la Menstruation, 1842 ; Raciborski, De la Puberte', 1844. UTERUS — (FUNCTIONS). during the existence of the menstrual pheno- mena, the blood was invariably found issuing from diseased surfaces situated upon or about the labia uteri, none escaping from the interior of the organ."* But in any case there is wanting a sufficient series of observations, taking cognisance of the exact duration and times of recurrence of such discharges, and comparing these with the normal periods and intervals of menstruation, to warrant an unhesitating belief in the occur- rence of a true catamenial flow as a possible phenomenon during gestation. Quantity. — The quantity of the menstrual fluid which escapes at each period has been so variously estimated at different times and by different observers, as to render it obvious that the calculations could not have pro- ceeded upon any common data. Thus Hip- pocrates, and afterwards Galen who quotes him, states the quantity as two Attic hemina, equal to about eighteen ounces. In recent times it has been estimated by Magendie at several pounds, and Haller gives the average amount as varying from six to twelve ounces. But all these estimates are too high. Dehaen, who employed an ingenious method of mea- surement, calculated that some women lost three, others five ounces, and very few half a pound ; but that it was exceedingly rare for a woman who had no malady to lose as much as ten ounces.f Probably the only proceed- ing by which any definite result can be ob- tained, is that of observing the rate of escape of the discharge from the uterine orifice. According to the observations of Mr. White- head, this is generally so slow that no more than from ten to twelve grains could be pro- cured during the time that the patient was able to endure the irksomeness of the pro- ceeding. From these, and similar observations of my own, as well as from other estimates, I conclude that two to three ounces is probably the full extent of the natural flow, and that a discharge amounting to six or more ounces in the aggregate will generally produce for the time sensible effects upon the constitution, such as general pallor, and some feebleness of the muscular system. Xature of the catamenial discharge. — There is no foundation for the belief once so preva- lent, and even partially still retained, that the menstrual fluid contains materials of a noxious or poisonous nature, nor yet that it serves as a vehicle for the depuration of the blood of the female. The occasional fetid odour of the discharge, and sometimes also of the breath of women during menstruation, arises from the decomposition of the fluid, as it slowly collects in the vagina, and doubtless also from its partial resorption into the system, producing in such cases a heavy or foetid odour of the breath, the cause of which was pointed out more than two centuries ago by De Graaf. J The menstrual fluid has always, even in health, a peculiar and somewhat heavy odour which * Whitehead, loc. cit. p. 24. t Brierre de Boismont, op. cit. p. 68. J De Mul. Organ. Lag. Bat 1672, p. 134. 663 is as characteristic of it, as is the gravis odor puerperii of the lochial and other discharges in childbed.* But these circumstances afford no evidence that the excretion is, when first formed, necessarily unhealthy. The menstrual fluid, when first formed, ap- pears to consist almost entirely of pure blood ; but, in its course through the vagina, it re- ceives in addition the secretions of that canal, whereby both its physical condition and chemical constitution are materially altered. Hence the differences of opinion which have so long prevailed regarding the real nature of this fluid, and the extent to which it differs from pure blood. These differences have been maintained chiefly by the well-known fact that menstrual blood seldom coagulates, and also by the difficulty of discovering fibrine in it. But a solution of this difficulty is found in the fact that the mucus of the vagina has always an acid reaction, and that in this acid the fibrine of the blood is so readily dissolved, that not only is its coagulation prevented, but chemical analysis fails usually to reproduce more than a trace of it. The menstrual fluid, therefore, as escaping from the vaginal orifice, and that collected from the os uteri, are essentially two different products, and this distinction should be ob- served in all examinations having reference to its chemical or physical composition. But it would be perhaps arbitrary to designate either of these alone the menstrual fluid. Probably this term is most suitable to the first. Both the vagina and uterus are concerned in the production of this fluid in the form in which it is most familiarly known, and in this form it may first be examined, the pure and un- mixed* product of the uterus being reserved for subsequent consideration. Composition of menstrual fluid according to Hf. Denis. Water - ... 82'50 Fibrine ----- Q'05 Hematosine - - - 6-34 Mucus ----- 4-53 Albumen - 4-83 Oxide of iron - 0-05 Osmazome and cruorine, of each - (Ml Salts and fatty matter - - 1*59 Microscopic examination. — The menstrual flux exhibits three periods or stages ; viz. the periods of invasion, stasis, and decline. In the first the discharge is of a paler colour, and sometimes consists mainly or entirely of mucus — menstrua alba. But this stage is not always observed, the discharge often commencing at once of the deep red colour characteristic of the middle stage. This con- tinues during the greater part of the period, and is succeeded by the third stage or that of * Doubtless this led Pliny to draw up that dire catalogue of evils, in which he informs us, that the presence of a menstruating woman turns wine sour ; causes trees to shed their fruit, parches up their young shoots, and makes them for ever barren ; dims the splendour of mirrors and the polish of ivory ; turns the edge of sharpest iron ; converts brass to rust ; and is a cause of canine rabies. — C. Plinii, Nat. Hist, liber vii. § xiii. ed. Cuvier, 8vo. vol. i. Paris, 1*27. V U 4 664 UTERUS AND ITS APPENDAGES. decline, when the discharge loses its deep red colour and assumes the hue of water in which raw flesh has been washed. This is very com- monly the condition of the discharge during the last day or two of each period, especially in those women in whom the flow is of long continuance. M. Pouchet* has examined with great care the menstrual discharge at each of these periods. The following are the results of his observations : 1st invasion. A very few blood globules mixed with mucus may be observed, together with mucous-corpuscles and scales of epithelium, mostly entire, floating in an abun- dance of limpid fluid. Almost all the mucous- corpuscles contain smaller globules or granules which form in them a central nucleus. 2. Stasis. Menstruation havingreached its apogee, the blood-globules are much more numerous than at the onset. The plates of epithelium usually remain entire. 3. Decline. The fluid contains the same substances, and presents nearly the same appearances as at the time of commencement of the flow. These observations agree generally with my own, and also with those of Donne, who found the menstrual fluid to consist of, 1. Ordinary blood-globules of the proper character, and in great abundance. 2. Mucus from the vagina mixed with epithelial scales. 3. Mucous- corpuscles from the cervix uteri. The unmixed menstrual fluid. — But in order to determine the nature of the menstrual fluid as it issues from the uterine orifice, unmixed with the secretions of the vagina, it must be collected by a speculum accurately fitting the uterine neck. The fluid so obtained possesses properties very different from those of the flux already described. Its sensible characters, as observed in more than a dozen specimens, are well described by Mr. Whitehead. Thus procured, the fluid is never so dark in colour as ordinary menstrual blood, so called, nor so fluid always as that of the arteries. Its colour varies slightly, but whatever is its tint, this is not subsequently affected by intermixture with the vaginal mucus. It appears usually rather more viscid than systemic blood, pro- bably on account of its slow exudation. When thus collected it invariably coagulates, the separation into clot and serum being complete in three or four minutes. It sometimes passes off" in a continued stream as pure blood, but more often as a thin coloured serum mixed with small flattened clots, the size of orange seeds, which, becoming broken down and, as it were, dissolved in the vaginal mucus, appear at the external orifice in the usual uncoagulable fluid form. It is invariably alkaline. In menorrhagia the discharge is as fluid as arterial blood, and not being delayed on ac- count of the greater rapidity of escape, it trickles in drops along the tube. On account of the great difficulty which is experienced in obtaining the pure fluid from the uterus in quantities sufficient for chemical * Theorie Positive, Atlas, plate xii. analysis, the following results by Bouchardat are the more valuable. The woman, a multi- para, was thirty-five years of age. To explain the large proportion of water Bouchardat states that she had subsisted chiefly on a vegetable and milk diet. BouchardaPs analysis of pure menstrual blood. Water - - 90-08 Solid matter - - 6'92 The solids were composed of — Fibrine, albumen, colouring matter - 75-27 Extractive matter - - 0-42 Fatty matter - 2-21 Salts - - 5-31 Mucus - -.. 16-79 100-00 It will be observed that the proportion of fibrine is here much larger than in the former example. But chemical analysis is not needed to show that this element of the blood con- stitutes a part of the fluid exuded from the uterus. For in women who have died men- struating fibrinous clots have been found in the uterine cavity ; coagula have also just been described as forming at the os uteri and mixing with the fluid collected by the specu- lum, and it cannot have escaped observation that clots sometimes form about the vulva, at times of menstruation, especially when the discharge is freer than usual. But the notion that the menstrual discharge differs from ordinary blood " in containing only a very small quantity of fibrine, or none at all,"* which view has gained general cur- rency of late, and in support of which the in- vestigations of Brande or Lavagna are usually quoted, appears to be altogether a modern one. For the older writers considered the menstrual discharge as identical with blood. Hippocrates says in reference to it, " procedit autem sanguis velut a victima, et cito coagu- latur, si sana fuerit mulier." Mauriceau-j- says that menstrual blood does not ordinarily differ in any way from that which remains in the woman's body. So also Haller and Hunter, both of whom regarded menstruation as a natural evacuation of blood. The results of these careful investigations therefore warrant the conclusion that the men- strual fluid, at the moment of its effusion, con- sists of pure blood, mixed only with the small quantity of mucus and epithelium which it receives in passing through the body and neck of the uterus, and that at this point it always has an alkaline reaction. But that in the course of its passage through the vagina the original fluid becomes mixed with the mucus of that canal, which there exists in increased quantities, and that in the acid of that mucus the fibrinous portion is so far dissolved as to render the detection, by chemical means, of fibrine, as a constituent of the secretion, diffi- cult or impossible. So much, however, of fibrine as belongs to the blood-corpuscles must always be present, for these bodies exist in * Mailer's Physiology by Baly, p. 1481. f Traite des Mai. des Fern. Gross, p. 45. 3rd ed. 1681. UTERUS — (FUNCTIONS). large quantities in every instance of a healthy menstrual flux. Source of the menstrual fluid. — The vagina, the os and cervix, and the body of the uterus, have been severally regarded as the parts which furnish the menstrual flux. And so far as the mucous element is concerned it is probable that all these surfaces contribute a certain proportion ; but that the blood in nor- mal menstruation is derived mainly from the lining membrane of the body of the uterus, is placed almost beyond doubt by the following considerations : — 1. In the uterus of one who has died whilst menstruating, a remarkable difference is usu- ally perceptible in the condition of the mu- cous membrane lining the cavity of the body and cervix respectively. That of the body is highly injected, of a deep red colour, the ves- sels distinct, and the capillaries numerous. That of the cervix exhibits a condition the opposite of this. It is pale, uninjected, and free from all appearance of distended vessels. 2. If such a uterus be injected, the same conditions are observed in a more marked degree. All the capillaries on the mucous membrane of the body are filled, but compa- ratively few of the cervix ; an abrupt line of demarcation occurring sometimes at the internal os uteri. 3. If gentle pressure be employed, as by taking the uterus in the palm of the hand, and slightly approximating the two sides, blood is perceived to flow up from the little pores or orifices of the utricular glands, which are everywhere perceptible, upon the surface of the mucous membrane, until this collects in the cavity in a quantity sufficient to cover the surface. 4. If the same experiment be made under water, in a dish or shallow basin, with the aid of very gentle pressure on the sides of the uterus, such as could not apparently cause any rupture of uterine vessels, the little streamlets of blood are seen welling up from each pore, and mingling with the water. In neither of these cases is the blood seen to proceed from any part of the cervix, but only from the lining membrane of the uterine cavity. 5. The blood, in ordinary menstruation, is seen to flow from the os uteri into the specu- lum, but is never observed to proceed from the lips of the cervix, except the latter be in an abnormal state.* 6. The cavity of the uterus, after death during menstruation, has been frequently found to contain blood or a coagulum. From these observations it may be con- cluded, that in normal menstruation the blood is furnished by the walls of the uterine cavity. Whether the lining membrane of the oviducts also contributes any portion of the fluid is not certainly known. But I have had reason to think this very probable, from observing that, in cases of death during menstruation, the tubes as well as the uterus contained blood, which * Whitehead, loc. cit. p. 24. 665 may in some cases, however, have entered them by regurgitation from the latter. (See also p. 618.) By what means does the blood escape from the uterine vessels in healthy menstruation ? — The investigation of this question is attended by great difficulties, and data sufficient even for its approximate determination are, yet wanting. The explanations which have been offered are chiefly the following : — (a.) The blood is supposed to escape in the form of a secretion. So long as it was maintained that the men- strual fluid differed essentially from pure blood, the view that it was eliminated from the general circulating current by a process analogous to that which obtains in true secret- ing glands received ready acceptance, and the menstrual fluid was, in accordance with such views, denominated a secretion. But since it is now known with tolerable accuracy to what portion alone of the menstrual fluid the term secretion can, with any degree of truth, be applied, it seems useless further to argue the question of secretion or non-secretion, in reference to the main ingredient of this fluid, which has already been shown to be pure blood, unaltered in its physical and chemical constituents, until after it has become mixed with other and adventitious matters. (6.) The blood is supposed to escape by transudation through the capillaries of the uterine mucous membrane. This view, which is proposed by Coste * and others, need not be considered specially with reference to the uterus. Those who think that the blood-corpuscles, which mi- croscopic examination proves to be abun- dantly present in the menstrual fluid, can pass by transudation, unaltered and entire, through the wralls of capillary or other vessels without rupture of their coats, will find no difficulty in applying this explanation to the production of a like phenomenon, as it may be supposed to occur in the uterus. (c.) The blood is supposed to escape through lacerated capillary vessels. Many observed facts give to this view a cer- tain amount of probability. Thus, in an in- jected uterus the capillary vessels, which form so fine a network upon its inner surface (fig. 439.), may be occasionally observed de- nuded, and hanging forth in detached loops. In such a condition I have found the vessels when death has occurred during menstrua- tion.f Unless this is a post-mortem change, which is improbable, it may be assumed that this laying bare of the capillaries is the conse- quence of a vital action, whereby a portion of the epithelial and mucous surfaces are broken * Histoire da Developpement, torn, prem., 1 fasc. p. 209. 1847. f I am not prepared to assert that this condition is always present during menstruation, or that it is limited to such periods. A larger number of ex- amples than those in which I have observed this feature would be necessary to establish such a fact ; and the whole subject requires a closer examination than has yet been given to it. 666 UTERUS AND ITS APPENDAGES. down, and subsequently discharged, along with the menstrual fluid. According to the observa- tions of Pouchet*, such an exfoliation of ute- rine epithelium takes place monthly in women and the mammalia generally. Pouchet, indeed, maintains that not only is there a monthly desquamation from the uterus, but that this extends to the separation and expulsion of a deciduous membrane on each occasion, and that this expulsion, which takes place in the form of the broken down elements of the deciduous lining of the uterus, constitutes the process described by him under the title of intermenstruation. Such an exfoliation, if it extended only to the epithelial cells sur- rounding the uterine capillaries, would simply leave them bare, but if proceeding to the ex- tent of removing the whole deciduous uterine lining, would of necessity carry off with it the whole capillary network of vessels, (see fig. 539.) lying upon the face of this membrane, and consequently would leave a surface of torn capillaries, from which the haemorrhage might occur f , and this in fact takes place in cases when dysmenorrhceal membranes are discharged (fig. 443.). (rf.) The blood is supposed to escape by permanent vascular orifices. In the present state of our knowledge, the evidence in support of this view is not more conclusive than that upon which the preceding hypothesis is built : yet many circumstances lend colour to it. The question of a termina- tion of the uterine vessels by open orifices has been occasionally, though obscurely, touched upon by different authors. Thus, Madame BoivinJ, a most careful observer, after speak- ing of the " perspiratory orifices of extreme minuteness," visible upon the inner uterine surface, evidently meaning the orifices of the now well-known uterine glands, describes the manner in which the blood may be made, by pressure, to appear in droplets upon the inner surface of the uterus when death has occurred during menstruation ; and,without giving a per- sonal opinion, she elsewhere quotes the then prevailing views, that the blood is furnished by the exhalent extremities of arteries termi- nating upon the inner surface of the uterus. Dr. Sharpey § endeavoured, by various ex- pedients, to determine what is the precise re- lation of the blood-vessels to these orifices * The'orie Positive, Huitieme Loi. f Pouchet, who does not enter upon the question of the effect which such a monthly denudation of the inner surface of the uterus would have upon its capillary vessels, nor, indeed, at all upon the con- sideration of the precise mode in which the menstrual fluid escapes, makes this supposed exfoliation and expulsion of the menstrual decidua occur at the periods intermediate between those of the menstrual flux. Thus the idea of a separative process, which might have been made comparable with that occur- ring in labour, when the entire ovum is thrown off and a bleeding surface is left, from which the lochi- al discharge takes place, loses its significance from the circumstance that this phenomenon is said to happen at periods when there is no bleeding. J Me'm. de 1'Art des Accouch., quarto ed. p. 61. § Miiller's Physiology by Baly, p. 1579. in the decidua a little more advanced*, as, for example, in early pregnancy ; but after express- ing his conviction upon the subject, the pre- cise anatomical connection between the two is left undetermined. Ordinarily, in injecting the uterus with fine coloured fluids, I have ob- served the cavity to become filled, the injec- tion apparently escaping by the glandular ori- fices, which also themselves may be seen filled with injection. In some specimens a capillary branch may be observed passing to and stop- ping short at one of these canals or orifices, and having much the appearance of an open vessel. Without personally expressing an opinion upon this point until I have carried further some experiments now in progress, I may observe, that the idea of a permanently open termination of vessels here need not be set aside upon the objection that such an ar- rangement would produce a constant bleeding, because the vessels supplying the blood must first pass through a dense muscular tissue, amply sufficient to control or arrest bleeding, as indeed it does effectually after labour, when much larger mouths are laid open, and also occasionally when menstruation is suddenly arrested by powerful mental impressions, acting apparently upon the muscular fibre of the uterus ; while many positive facts might be adduced in support of such a view, such as the frequent bleedings of uterine polypi, which are always invested by mucous membrane, the ready passage of fluids through the surface of the latter when their main vessels are injected, and the like. What is the purpose of menstruation ? — To this question no reply will be satisfactory which does not include the consideration of many other circumstances besides the mere escape of blood. Menstruation has evidently a much deeper signification than is declared simply by the flux, which is probably not the most important part of the function, although it constitutes the external sign or evidence of it. Amid all the crude hypotheses of former times, such as that menstruation is due to fer- mentation, lunar influence, and the like, some of the older writers appear nevertheless to have had a dim perception of the truth when, under the form of an elegant type, they shadowed forth that which appears to be the real pur- pose of the menstrual act. The French term, " fleurs," and the English, " flowers," are now fallen into disuse ; but they were employed in earlier times as designations of menstruation, for the purpose of suggesting that, after the example of trees, which do not bear unless the fruit is preceded by the blossom, so a woman does not become pregnant until she also has had her flowers.f Menstruation is not established until the ovaries have reached a certain stage of de- velopment, and the maturation and discharge * It must be observed that throughout this article the terms " decidua " and " mucous or lining membrane of the uterus" are employed as strictly synonymous. f Mauriceau, Malad. des Femmes grosses. 1681. UTERUS —(FUNCTIONS). of ova has commenced.* It continues to be performed as long as the process of ovulation is continued ; but when the latter ceases, and the ovaries have become shrunken, their tissues attenuated and wasted, and Graafian follicles can be no longer distinguished, menstruation ceases to be performed. These facts show that menstruation and ovulation proceed pari passu ; but they do not alone prove that the one function is dependent upon the other. If, however, both ovaries are congenitally deficient, no attempt at menstruation is ever observed ; while, on the other hand, in cases where the ovaries are present but the uterus is deficient, puberty becomes established in due course, and then a regularly recurring menstrual molimen may be observed, although for the want of the uterus this function can- not be carried out. See note §. Or if, under ordinary circumstances, after the regular establishment of menstruation, both ovaries become extensively diseased, or both are removed by operationf, menstruation is from that moment permanently suspended. Hence it appears that the presence of the ovary in a healthy state is essential to men- struation. But something more also is needed ; for the ovaries may be present and healthy, yet if they cease for a time to mature or emit ova, as for example during pregnancy and lactation, when they are passive j, then, so long as those processes endure, menstruation is also com- monly suspended, but returns after the com- pletion of one or both of them. A series of facts so consistent appears to admit of but one interpretation : namely, that a menstruating condition of the uterus bears a direct relation to the active operations of the ovaries, and that this function is only per- formed under circumstances which render pregnancy possible so far as the ovaries are concerned ; but if the conditions are such that impregnation cannot take place, then the ute- rus, although it may be healthy, does not menstruate. But, in addition to this general relationship between menstruation and ovulation, it is ne- cessary to determine further if any direct cor- respondence exists between each separate act of menstruation and the maturation or dis- charge of one or more ova from the ovary, so that these two acts shall be coincidentally performed. The following evidence supports this view. The ovaries at the menstrual periods are not unfrequently the seat of pain and tender- ness, indicating some unusual activity of this part. This is most remarkable in the rare case of hernia of the ovary.$ * The views of Dr. Ritchie in dissent from this statement have been already noticed, p 572. f See Mr. Pott's case, p. 573. J Negrier's, loc. cit. § In a case of this kind recorded by Dr. Oldham (Proceedings of the Roy. Soc. vol. viii. p. 377.), both ovaries had descended through the inguinal canals, and were permanently lodged in the upper part of the external labia. "At intervals of about three 667 In women who have died during a men- strual period the ovaries have been frequently observed to present unmistakable signs of the recent rupture of one or more Graafian fol- licles. Some examples of this fact have been already given. In one case the ovum itself was found in the Fallopian tube (p. 567.).* Conception is supposed to take place most frequently within a few days after a menstrual period, and therefore during the time which an ovum, if it were emitted from the ovary during menstruation, would occupy in passing down the Fallopian tube and perhaps in ar- riving at the uterus. Menstruation corresponds in many particu- lars with the oestrus, or rut, in the mammalia, and in them it is only during the oestrus that ova are emitted from the ovaries, and that con- ception can take place. The foregoing facts constitute evidence bearing upon two distinct points. The first series proving that a menstruating condition of the uterus is maintained only so long as the ovaries continue in the active performance of their function of preparing and ripening ova. The second series affording a certain amount of presumptive evidence, that each separate act of menstruation is connected with or is dependent upon a corresponding act of maturation, and perhaps of spontaneous emission of one or more ova from the ovaries. The accuracy of the first conclusion will probably not be questioned ; but if the second point is to be regarded, as at present, more than an hypothesis having many facts and probabilities for its support ; if, as M. Pouchet believes, we are justified in considering as established laws of generation that in man ova are emitted from the ovary at fixed epochs and at no other times, and that these occa- weeks one or both ovaries were observed to become painful and tumid, the swelling augmented for four days, remained stationary for three days, and then gradually declined ; the whole process occupying generally from ten to twelve days. It happened, unfortunately, that in this case the uterus and va- gina were deficient, so that menstruation could not take place ; but the case in one respect is the more interesting on that account, for notwithstanding the absence of the uterus, all the external signs of pu- berty were present, and the evidence of a periodical activity and excitement of the ovaries, and of a menstrual molimen affecting the organs which were not malformed, were here unmistakable. These circumstances forcibly call to mind the painful condition of the ovaries which, in a similar case, induced Mr. Pott to extirpate those organs. * Upon the connection between the discharge of ova from the ovaries, and the phenomena of heat and menstruation, the following should be con- sulted, viz. : — E. Home, Lectures on Comparative Anatomy, vol. iv., and Phil. Trans. 1817 and 1819; Power, Essays on the Female Economy, 1821; R. Lee, Cyclopaedia of Practical Medicine, art. Ovary, 1834 ; Gendrin, Traite Philosophique de Medecine Pratique, t. i. 1839; W. Jones, Practical Observations on Diseases of Women, 1839 ; Paterson, Edinb. Med. and Surg. Journ. vol. liii ; Girdwood, Lancet, 1842-43 ; in addition to the works of Bis- clu>jf, Raciborski, Negrier, Coste, and Pouchet, al- ready quoted under the title OVARY, p. 568., where will be found a full account of the process of ovula- tion. 668 UTERUS AND ITS APPENDAGES. sions, which furnish the sole opportunities for impregnation, bear the same constant relation to menstruation that the acts of ovulation and the times of conception in the mammalia bear to the oestrus, it becomes necessary to exa- mine more closely the grounds of this belief; and for this purpose the circumstances as yet ascertained regarding the times of conception in women, the condition of their ovaries, not only during menstruation but in the intervals also, and the actual relation which the oestrus, or period of conception in mammals, bears to menstruation, may be briefly passed in review. The precise period at which conception in the human subject occurs in most cases cannot, for obvious reasons, be determined, but when- ever conception can be traced to a single op- portunity, the process of impregnation, or the fertilisation of the ovum by contact with the spermatozoa, may be assumed to take place within a few hours after the act of insemina- tion ; for the spermatic fluid rapidly traverses the generative canal, while here spermatozoa cease to have motion within thirty hours at latest from the time of emission. From various methods of computation it is supposed that in a large majority of cases con- ception occurs during the first half of a men- strual interval, and most commonly during the first week. In sixteen instances noted by Raciborski conception occurred as late as the tenth day after menstruation in only one case.* The number of instances in which con- ception can be ascertained, or may be fairly assumed, to have taken place in the latter half of a menstrual interval is comparatively small. Nevertheless impregnation may unquestionably occur during this time, and even within a day or two of the next menstrual flow, which is then usually diminished in duration and quan- tity, or is reduced to a mere show. Now if we endeavour to explain these facts, relating to the times of conception, by the aid of an ovular theory of menstruation, the ques- tion may be brought within very narrow limits. One of two postulates may be assumed. An ovum emitted at or soon after a menstrual period either remains susceptible of impreg- nation through the whole of the succeeding interval, or it loses that susceptibility, and perhaps perishes before the recurrence of the next menstrual flow. The first hypothesis would sufficiently account for impregnation taking place at any part of a menstrual interval ; but it has little or no evidence for its support. Nothing, in- deed, is known regarding the length of "time during which the human ovum remains sus- * These and similar facts have been commonly regarded as showing a greater aptitude for concep- tion shortly after menstruation ; but the influence of mere opportunity has not perhaps been sufficiently considered ; for if, as in the case of the Jews under the strict requirements of the Levitical law, the whole of the first week, or that period which is commonly regarded as most favourable to concep- tion, be withdrawn from the opportunities for im- pregnation, no diminution whatever of prolific power results. ceptible of impregnation after it has escaped from the ovary. The period of susceptibility in the mammalia generally is variable. In the bitch, as already stated (p. 606.), the ovum, after quitting the ovary, is supposed to re- main in the tube during six or eight days. Its passage is probably quite completed in ten days. In the guinea-pig the period is much shorter, as the ovum enters the uterus at the end of the third day. In the rabbit also the pe- riod does not extend beyond the beginning of the fourth day. But by the time that the ovum reaches the uterus, or sometimes even the lower end of the oviduct, in most of the mammalia yet observed, the oestrus is past, and with it also the opportunity for impregnation. The evidence therefore obtainable from the mam- malia fails to support the conjecture, that in man an ovum detached during menstruation can remain susceptible of impregnation through the whole of a menstrual interval, consisting of twenty-three or more days, although the period of this susceptibility may be longer in man than in the other examples cited. But if this first hypothesis fails, the second appears inevitable, viz., that an ovum emitted during menstruation loses its susceptibility of impregnation before the termination of the succeeding menstrual interval. M. Pouchet supposes, that in the human subject the dura- tion of this susceptibility does not exceed four- teen days. Consequently if, according to the strict formula of the latter physiologist, ova are emitted only at or shortly after the menstrual periods, there must remain a portion of each menstrual interval, during which every woman is physically incapable of conception. And this alternative M. Pouchet* does not hesitate to adopt. But since this conclusion is incompatible with the facts already stated regarding the occasional, though probably rare occurrence of conception during the latter portion of a men- strual interval, and especially towards its con- clusion, M. Coste, who shares with many others a belief in these facts, has proposed an explanation which constitutes a very con- siderable modification of the ovular theory of menstruation. To account for impregnation at a later period than usual of a menstrual in- terval, M. Coste supposes that a ripe or dis- tended Graafian follicle, having failed in reach- ing the point of rupture, may remain stationary, as it sometimes does in mammals f, and that the influence of the male is sufficient to de- termine the dehiscence of a follicle in such a state. And in order to anticipate the obvious objection, that if the emission of an ovum from the ovary is the cause or occasion of menstrua- * Theorie Positive. — M. Pouchet believes that a slender decidua is always formed at the decline of each menstruation, which, together with the ovum, whenever the latter is not impregnated, is cast off from the uterus between the tenth and fourteenth day, and that after this event every woman remains incapable of conception until the" next menstrual period, when the detachment of another ovum from the ovary renews her capacity for impregnation. t For a fuller statement of this view, with illus- trative examples, see p. 568. UTERUS — (FUNCTIONS). lion, the latter phenomenon ought to be re- peated whenever the former event occurs ; and consequently in the case now under conside- ration M. Coste suggests that the same cause which provokes the discharge of the ovum in this case, also occasions fecundation, which arrests the menstrual flux before this has time to manifest itself. Thus, if even the foregoing explanation could be deemed satisfactory, it appears ne- cessary occasionally to fall back upon the old doctrine of the detachment of ova coincidently with fecundation, in order to supply the de- ficiencies of the newer theory of their sponta- neous emission independently of it. It must however be confessed, that every view yet offered of the direct dependence of each sepa- rate act of menstruation upon a corresponding act of ovulation, disappoints expectation by leaving some condition relating to conception unexplained, or explainable only by raising an additional hypothesis ; while many circum- stances of common occurrence, such as the sudden reappearance of menstruation under mental emotion and the like, are left unac- counted for upon any hypothesis of ovarian dominance. If next the ovular view of menstruation be tested by the evidence derived from anatomy, although many facts will be found in proof of the statement that ova are often emitted at the menstrual period, these cases have not been yet sufficiently collated to form a series capable of affording unquestionable conclusions as to the precise relation which the emission of ova bears to each menstrual act. That ova may pass spontaneously from the ovary during the menstrual flow is proved by cases already given at p. 567. and 605. M. Pouchet, however, supposes that it is the maturation of the ova which takes place during menstruation, and that their emission follows immediately or within four days after the cessation of the flow. M. Coste found the period of rupture of the Graafian follicle to be very variable. In one case the follicle was already burst on the first day of menstruation. In a second in- stance, although jive days had passed from the cessation of the flux, the follicle was still entire, though the slightest pressure sufficed to cause its rupture. In a third casefifteen days had elapsed, and yet rupture had not taken place. In the example represented by fig. 380. ten days had passed since the last men- struation began, and the follicle was entire, though perfectly ripe, and apparently upon the point of rupture. These examples, in the same degree that they favour a belief in the occurrence of im- pregnation at indefinite periods of the men- strual intervals, by showing how conception is then possible, discourage the view that the emission of ova is necessarily limited to the precise times of the menstrual flow. But until a larger number of examples than yet exists, showing the condition of the follicles during both the menstrual periods and inter- vals, has been collected and carefully com- pared, no definite conclusions as to the exact 669 relation which the emission of ova bears to each act of menstruation can be arrived at, so far as anatomical evidence is concerned. For the attention of observers having been directed more to the condition of the ovaries at the time of menstruation than in the inter- val, much more has been ascertained of their state at the former than at the latter periods. Yet it is during the intervals of menstruation that conception in man normally takes place, while mammals become impregnated only during the oestrus. It is important, therefore, to determine, thirdly, how far the oestrus or rut in the mam- malia may be regarded as comparable with the act of menstruation in the human female; for if, as is commonly supposed, these two functions are identical, or nearly so, then the facts to be derived from comparative anatomy may assist further in determining the nature and extent of the relation between menstruation and ovu- lation in man. But if the phenomena atten- dant upon the rut do not, in all respects, coin- cide with those accompanying menstruation, the conclusions which are legitimately de- ducible from observation of the former func- tion must not be too strictly applied to the latter. In the mammalia the periods of emission of the ova from the ovary, and of their passage down the Fallopian tube, are undoubtedly coincident with the oestrus. It is only on these occasions that the female manifests an instinc- tive desire for copulation. She is then said to be in heat. The vulva is congested, swollen, and bedewed with an increased secretion, which is generally odorous, and is sometimes tinged with blood. This condition is of brief duration. At the longest it continues for a few days. But whatever be its duration it is the only period during which the female can be impregnated. In the human subject the periodical return of congestion of the reproductive organs, the menstrual flow, and the corresponding spon- taneous emission of ova, so far as this point has yet been ascertained by post-mortem ex- amination, accord with the phenomena dis- played by the mammalia during the oestrus. It is also believed that in some instances concep- tion has taken place during menstruation*, a circumstance which is clearly reconcilable with the anatomical evidences already produced, and is so far in accordance with what nor- mally occurs in the mammalia during oestrua- tion. But here the analogy ceases. And from this point onwards the more closely the two functions are compared, the more plainly does it appear that although the oestrus and men- struation possess many circumstances in com- mon, yet the resemblance endures only for a certain period, more or less brief, while, after this is past, there follows in man an inter- mediate condition which is not only not com- parable with the corresponding intermediate * Some of the few authorities for this fact extant are quoted in the works of Pouchet and Coste, foe. cit. 670 UTERUS AND ITS APPENDAGES state in animals, but is in many of its essential features the direct converse of this. For, as already stated, in the mammalia usually by the time that the ovum has reached the uterine extremity of the oviduct, or has entered the uterus, the opportunity for im- pregnation is lost, the oestrus is over, and the animal refuses the male : all the conditions immediately necessary to procreation then pass away, and an interval of perfect inaptitude en- sues, which is sometimes so remarkable that not only are no ripe ova to be found in the ovaries, but even the male organ ceases to secrete semen. In this series of recurrent periods, marked by irresistible impulse, alter- nating with total inappetence for congress, nothing is more evident than that each corre- sponds with an internal physical condition, of which it affords a most intelligible explana- tion. The appetency occurring and remain- ing only as long as congress would be fruitful ; the inappetency returning whenever this would be necessarily infertile. Now, with regard to the human subject, whatever may be possible during menstruation, yet essentially the intervals of the menstrual acts are the times of fertility in women. And the only question that can arise upon this point is, whether the power of conception ex- tends over the whole or over a part only of this interval — a question that has been already considered. In all that relates, therefore, to the coinci- dence of the ovipont with the oestrus of mam- mals, the evidence derived from comparative anatomy serves to strengthen the belief in a corresponding correlation between the emis- sion of ova and the act of menstruation in the human subject. But in respect of the inter- val, the great divergence of the facts here dis- played tends to embarrass and perplex rather than to elucidate the question as it relates to man. For it is precisely in this interval that all the circumstances occur which, for want of a consistent explanation, have often thrown a doubt over the whole theory of the direct dependence of menstruation upon ovarian in- fluence ; and in elucidating these points, com- parative anatomy affords little or no help. In taking a retrospect of these several facts relating to menstruation and its connection with a corresponding ovipont, an essential distinction should be made between the influ- ence of the ovaries in determining the power of the uterus to perform the menstrual act, and any influence which they may have over the periodicity of that function. In all that relates to the former faculty, the power of the ovaries may be regarded as indisputably esta- blished. In much that is connected with the latter, there is obviously room for more in- formation than we at present possess. If each separate act of menstruation is de- termined by certain modifications periodically occurring in the ovary, it is probable that the essential part of the process is the maturation of an ovum within the follicle, while the process of its emission may be an accidental feature, not always occurring, sometimes hap- pening spontaneously, and sometimes caused in the way already suggested, but having nothing necessarily to do with the menstrual act, although the time of its occurrence may materially affect the period of a resulting im- pregnation. The purpose of \hejlux remains to be con- sidered. If the quantity of fluid escaping at each recurrence of menstruation be estimated at three, or possibly five, ounces, and the pro- cess is repeated, without interruption from pregnancy, lactation, or disease, once in every lunar month, or thirteen times annually for thirty years, then an aggregate quantity of seventy-two pounds or nine gallons on the for- mer supposition, or of a hundred and twenty- two pounds or fifteen gallons upon the latter estimate, will have passed from the system in the course of menstrual life, and, so far as this is composed of blood, will have been ap- parently entirely wasted. It is difficult to arrive at a perfectly satis- factory conclusion regarding the purpose of this large loss. For the external escape of blood must be regarded as, to a certain ex- tent, an accidental feature in the process of menstruation. That it is not essential to fer- tility, is proved by the fact that women some- times, though very rarely, breed who do not menstruate ; that the temporary suspension of the menstrual flow during lactation is no cer- tain preventive of conception ; and that, oc- casionally, young girls become pregnant before the menstrual age has arrived. The blood which escapes is certainly con- verted to no positive use. No office can be assigned to it, such, for example, as has been suggested for the analogous escape of blood into the ripe ovisac — an effusion that has been termed the menstruation of the follicle.* But although the blood, after it has passed the uterine epithelium, is altogether lost, it may, by escaping, fulfil the negative purpose of affording relief to the congested capillaries of the uterus. For we find, from various kinds of evidence, that, at each menstrual period, all the uterine tissues become charged with a more than ordinary quantity of blood, and, therefore, with the materials necessary to those rapid growths which have been shown to commence as soon as impregnation has taken place. From the moment that the latter occurs, the mucous and other tissues of the uterus begin rapidly to expand, and the current of blood is diverted to new chan- nels. There is then no overplus, until the whole cycle of generative acts, including lacta- tion, is complete. The only observable break happens at parturition ; but after the balance of the uterine circulation has been restored by the escape of blood at the time of labour, and by the lochia, there is again usually no redundance until the office of the mammary glands has ceased. Then, the activity of the ovaries recommencing, the periodical hyper- aemia of the uterine vessels returns, and the overplus is emitted in the form of menstrual * See p. 556. UTERUS— (FUNCTIONS). blood. And thus, by each act of menstrua- tion, the uterus is placed in a state of prepa- ration for that profuse development of its tissues which impregnation may at any time of the succeeding interval call forth. The office of the uterus in insemination. — After menstruation, which is to be regarded as a process preparatory to impregnation, the next office of the uterus is that of receiving the seminal fluid, and apparently of conducting it to the Fallopian tubes, by which again it may, in rare instances, be carried as far as the ovary. To this office the form of the uterus appears to be well adapted in all its parts. For, first, the cervix uteri is so constructed as to lie in the centre of the upper dilated portion or fornix of the vagina, into which it projects to a distance of 3 — V". This dilated ex- tremity of the vagina forms a pouch which re- ceives the extremity of the intromittent organ, and in this receptacle the seminal fluid is de- posited. But, on account of the natural posi- tion of the uterus, which lies in the axis of the pelvic brim, while the course of the vagina corresponds with that of the cavity and out- let (Jig. 433.), the cervix uteri is so directed (downwards and backwards) as to cause the os uteri externum to be maintained in the very centre of this pouch, so that the seminal fluid will be retained in a situation in which it is most certain to flow through this orifice into the cervix.* But the cervical canal is traversed by numerous furrows, which will act as so many channels, conducting the semen to the internal os, while the dilated central portion of that canal (jig. 424.) serves the purpose of a second reservoir. It may also be readily believed that the ejaculatory act on the part of the male will suffice to carry the seminal fluid thus far, although the impetus with which it is propelled having been checked by the constriction caused by the external os uteri, would hardly suffice to carry it much beyond the more narrow bar- rier existing at the internal os. Or if it should pass this second obstacle, the almost complete apposition of the walls of the uterus would prevent any considerable penetration of the semen further into the uterine cavity, so far as this is dependent on the act of ejaculation. But this very apposition of the uterine walls may, in another manner, assist the onward progress of the semen, by inducing a kind of * Dr. James Blumlell has described a peculiar movement which he observed in the vagina of the rabbit, and which serves to explain the mode of in- troduction of the seminal fluid into the uterus : — " This canal during the heat is never at rest ; it shortens, it lengthens, it changes continually in its circular dimensions ; and when irritated especially will sometimes contract to one-third of its quiescent diameter. In addition to this action the vagina performs another," which "consists in the falling down, as it were, of that part of the vagina which lies in the vicinity of the wombs ; so that it every now and then lays itself as flatly over their orifices as we should apply the hand over the mouth in an endeavour to stop it How well adapted the whole of this curious movement is for the introduction of the semen at the opening it is needless to explain." —Researches Phys. and Pathol. p. 55. 1825. 671 capillary attraction, such, for example, as will cause water to rise, to a certain distance, be- tween two plates of glass placed in close con- tact. The rigid walls of the human uterus, which are normally in such close apposition that sections made in certain directions scarcely suffice to display any appreciable cavity {figs. 426. and 427.), seem admirably adapted to fa- vour this gradual rise of the seminal fluid be- tween them towards the Fallopian tubes ; and thus a compensation is provided for that peri- staltic movement, which, in some mammalia with a more intestiniform and less rigid uterus, appears, under the influence of the coitus, to affect alike the vagina, uterus, and Fallopian tubes*,and to suffice for the conveyance of the seminal fluid from one extremity to the other of the generative track. The action of the cilia of the uterine epi- thelium cannot, in any way, contribute to this result, if those observations are correct which agree in assigning to them a movement such as would create a current from within out- wards ; for it is obvious that such a motion would tend to retard rather than to advance the progress of the seminal fluid towards the Fallopian tubes. If therefore any other power is needed to account for this movement, it must be sought in the action of the spermatic particles them- selves. For, little adapted as their motions appear to anything like onward progression, yet they have been observed to continue long after ejaculation, in the fluid found within the uterus and tubes, and even upon the ovary.-f- It has been also proved beyond doubt that by this power the spermatozoa penetrate the ovum itself J, and therefore to it may be attributed a certain share in the progress of the seminal particles through the uterus towards the ovi- ducts, although this may not be a very con- siderable one. Finally, it is possible that in man and the mammalia some such remarkable property may be possessed by the spermatozoa as that which I have observed in certain annellides. If a portion of the contents of the testis of the com- mon earth-worm (Lumbncus agricola, Hoffm.) be placed under the microscope between two slips of glass, in about ten minutes the whole mass is seen to heave and writhe with aston- ishing energy, the form of the movement being that of the peristaltic action of the intestines (fig. 459.). Everything in contact with the spermatozoa becomes ciliated by them, one end of the filament fixing itself while the other vibrates free. The result is, that if the body to which the spermatozoa attach themselves is fixed, such as the glass, or the margin of a mass of granules, a line of cilia is formed whose action creates a strong current, and everything movable is drawn into the vortex, and is seen drifting rapidly along. But if the body to which they attach themselves is movable, then this soon becomes clothed with spermatozoa, * Blundell toe. ctt.; see also p. 611. of this article. t See this article, p. 607. J Newport, Phil. Trans. 1853. Pt II. p. 267. 672 UTERUS AND ITS APPENDAGES. whose free ends moving rapidly, cause the whole to rotate. A most remarkable object Fig. 459. Spermatozoa of Lumbricus agricola in motion and forming cilia. {Ad JViatf.) is thus formed, which continues for a con- siderable time in motion, clearing for itself a free area, and in this it revolves, whilst its revolutions are apparently assisted by the ac- tion of other spermatozoa, which, having at- tached themselves to the periphery of the cleared space, keep up a perpetual vortex, in which the central body is partly a passive arid partly an active agent.* Whether any similar effect is capable of be- ing produced by the spermatozoa in the human subject, or how far this property may be ge- neral in spermatozoa, I am not aware ; but the circumstance is altogether too remarkable to be passed over without mention here, as it may serve to explain how the onward move- ment of spermatozoa can, in some cases at least, be aided by this peculiar property of the spermatic filaments to attach themselves to surfaces with which they were in contact, and to clothe these surfaces with a fringe of cilia capable of producing the ordinary effects of cilia in motion. The office of the uterus in gestation. — The process of gestation may be considered to commence from the moment that the ovum, which has been subjected to the fertilising in- fluence of the male generative element in the Fallopian tubef, is received impregnated into * These observations were first made by me at the time when the late Dr. Martin Barry announced his discovery of the penetration of the ovum by the spermatozoa in the rabbit, and were communicated to him, and subsequently for publication to Prof. Owen, in Avhose lectures on the invertebrata this account appears. Lectures on the Comp. Anat. and Phys. of the Invertebrate Animals, by Richard Owen, F.R.S., 2nd edit. p. 257. t Seep. 609. the uterine cavity. If no such contact of the generative elements as is necessary to the de- velopment of the ovum takes place, then the latter suffers no further change beyond that slight alteration in its condition during its passage through the oviduct, which has been already described ; and ultimately it becomes lost, probably suffering decomposition, but at least giving no evidence of its presence in the uterine cavity. But if the ovum has been fer- tilised, then commences that remarkable series of changes in the physical condition of the uterus whereby this organ is fitted for the pro- tection and nutrition of the ovum during the usual period of forty weeks in which the latter is normally retained within its cavity. As these changes involve very considerable alterations in the form and composition of the entire uterus, as well as of its several parts, they have been considered as a part of that series of meta- morphoses which the uterus undergoes in its progress from infancy to old age, of which a description has been already given, (p. 644.). The office of the uterus in parturition. — The act of parturition, or that process by which, in normal cases, the product of conception, after due development, is spontaneously sepa- rated and expelled from the parent body, con- stitutes the last chief office of the uterus. The labour process may be regarded as es- sentially a contest between two opposing forces, which are resisting on the one hand, and propulsive on the other. Resistance is necessary to preserve the foetus in its place. Propulsion is requisite to detach and expel it from the parent body. The resisting force is chiefly passive in its operation. It is that which is offered by the membranes enclosing the foetus, by the os and cervix uteri, by the soft parts lining and closing in the pelvis, and lastly by the osseous and ligamentous struc- tures of the pelvis itself. Naturally, these are sufficient to counteract any tendency to the escape of the foetus from the operation of gravity upon it, in various changes of posture, or under any impulsive movements of the parent body. Their combined resistance is such as to require the operation of powerful mus- cles to overcome them before the child can be expelled. This power is supplied by the uterus, aided subsequently by the diaphragm and other muscles, abdominal and pelvic. Labour constitutes the performance, and birth the end of the process, for the accomplishment of which in a natural manner the forces should be nearly evenly balanced. The preponde- rance of power being, however, at first, on the side of resistance, and finally on that of pro- pulsion. Whenever the forces are thus pro- portioned, the act of parturition is, c&teris paribus, natural. Whenever they are greatly disproportioned, the process is abnormal ; whether the error be on the side of too much resistance, or too little propulsive force. In these last two particulars may be compre- hended the history of every unnatural labour in which the mechanism* is at fault. * The mechanical operation of the parts con- cerned in labour having been reserved for con- UTERUS — (FUNCTIONS). When labour is about to commence, the uterus having previously taken a lower posi- tion in the pelvis, begins to contract gently, and often without pain, so that the only or chief evidence of its action is an occasionally recurring tension and hardness of the organ. These contractions commence apparently at the cervix, so far as it is possible to analyse them, and travel onwards towards the fun- dus * : the whole organ soon becoming firm and resisting to the touch, and its upper part rising and assuming a more prominent posi- tion in the abdomen. This hardness and tension is occasioned partly by the rigidity of the whole fibre, in a state of tonic contraction, and partly by the resistance offered by the in- compressible contents of the organ, for which there is no exit so long as the cervix remains closed. The contraction having overspread the uterus, a sense of pain is now first felt ; the pain, like that of cramp, being usually propor- tionate to the sensible tension and hardness of the organ. After enduring for a time the state of con- traction gradually subsides, and is replaced by one of relaxation. In subsiding, the con- traction observes the same order as in com- mencing, the os and cervix yielding first, while the upper portion and fundus remain longest tense and hard. From this it results that the antagonistic force, exerted by the two ex- tremities of the organ, not being throughout contemporaneously and equally employed, the excess of the fundal over the ostial contrac- tion will represent the measure of the unop- posed, and consequently efficient, propelling power. The period of action is followed by one of repose, in which the organ remains relaxed, and no pain is experienced. After an interval of variable duration con- traction returns, and continues to recur in rythmical order, but with a gradually diminish- ing interval, while at the same time the con- tractions, especially at the fundus, increase in intensity and duration. As a result of these successive contractions, the os and cervix slowly yield, and a portion of the foetal membranes, containing some liquor amnii, protrudes, in the form of a pouch. This, as the os uteri becomes still further opened, is followed by the head or some other portion of the child, which, having entered the vagina, ultimately fills up the pelvis, and distends the perineum. At this period the abdominal and pelvic muscles are brought powerfully into play. Their cooperative action is occasioned by the parts of the child occupying the pelvis irri- tating structures which are abundantly sup- plied by spinal nerves. And now the chief use of spinal reflex action, in relation to sideration in a separate article (PARTURITIOX, MECHANISM OF, Vol. III. of this Cyclopaedia), the vital endowments only of the uterus, as far as these relate to the parturient act, are here examined. * Wigand, Die Geburt des Menschen. Berl. 1820. Supp. 673 labour, becomes manifest, not so much in regard to the uterus itself, whose contractions are probably still mainly dependent upon its own sympathetic nerves, as in that correlation with other parts, between which and the uterus it is essential that consentaneous action should be occasionally established. The powerful cooperation of the abdomi- nal muscles, which form as it were an addi- tional sheet of contractile fibre, nearly sur- rounding the uterus, being thus enlisted, the passage of the child is completed with greater rapidity and certainty ; and, after a pause, the placenta and membranes are expelled, the liquor amnii having, either altogether or in part, escaped at some earlier period of the labour. This general sketch of the operations of the uterus in labour will suffice as an intro- duction to a more detailed and critical exami- nation of the nature of the forces employed, and of the manner in which these are called forth. Of the peristaltic action of the uterus t and its cause. — From direct observation upon many mammalia, it is known that the action of the uterus is in them peristaltic, i.e., the contrac- tions commence at certain points, and pass on from segment to segment slowly, and in a ver- micular manner. If a single point of an organ so composed is irritated, the action starts from the point of irritation, and spreads outwardly, and by irritating different points, other peri- staltic centres may be obtained. Although the human uterus does not admit of the same direct methods of observation w hich can be employed in animals, yet from all that is known, we may conclude that its mode of contraction does not differ in any important particular from that of other simi- larly constructed hollow muscles, when en- gaged in propelling or expelling their contents. The principal circumstances bearing upon this point in regard to the human uterus are the gradual and slow contraction, followed by an equally slow return to a state of relaxation — phenomena easily observed, when the hand is placed upon the abdomen of a woman in labour — a certain tremulous motion of the os uteri, when contraction is commencing, fol- lowed by a sensible gradual hardening of the uterus, before the woman is herself conscious of pain ; the longer abiding of the contrac- tion at the fundus than at the cervix ; and the occasional segmental contraction of the organ after labour, commonly termed hour- glass contraction *, which may occur at any point intermediate between the fundus and cervix, and which resembles similar contrac- tions of common occurrence in other hollow muscles, whose action is peristaltic. These several circumstances, added to the general analogies, suffice to show that the action of the human uterus is peristaltic. Peristaltic action, as it occurs in vertebrate animals, is found to depend upon the struc- ture of the organ displaying it, rather than * See p. 702. x x 674 UTERUS AND ITS APPENDAGES. upon the mode of its innervation or excite- ment. So that if in a situation where organic fibre is usually found, the intestine, for ex- ample, of cyprinus, the part is composed of striated muscle, then no organic or peristaltic action can be produced in it ; but upon excite- ment, contractions of the kind usually seen in striated muscular fibre ensue.* In the same way the peristaltic action of the uterus, although exhibiting certain differences, according to the manner in which it is evoked, is nevertheless to be referred to the peculiar composition of unstriated fibre, and not to the mode of innervation or excitement of the organ. For the muscular fibre of the uterus is not bound up in separate sheaths, as voluntary muscles are, nor do the fibres run principally in one direction, nor are they long and con- tinuous— conditions all favourable to that quick transmission of nerve influence, and rapid action which occur in voluntary muscle — but the fibre cells are for the most part distinct, lying in apposition, or imbedded in a matrix of amorphous tissue (jig. 436.), and forming by their combination intricate laminae. Through a tissue so composed, the in- fluence of a stimulus can only be propagated slowly, and the organ formed of it can only contract after a vermicular or peristaltic man- ner. Nevertheless, the power, the endurance, and the orderliness of the action that ensues, will be, to a certain extent, dependent upon the nature and mode of application of the excitant. It cannot be questioned that, under many circumstances, the direct application of a stimulus to the uterine muscular structure excites its contractions in the same manner that the food does those of the oesophagus and intestines, without any intervention what- ever of nerve. This happens when the hand is passed into the bare uterine cavity after labour, or when the membranes are separated from the inner surface of the uterus by a catheter. To bring such an organ into co-ordinated action, all that appears necessary is, that nerve fibres should enter its tissue at a certain number of distinct points or centres, whence the irritation excited at these spots being propagated from fibre to fibre, may spread through the mass, until the whole is brought into harmonious operation. And it need not excite surprise if these centres of excitement are few, and the nerves of the gravid uterus consequently not nume- rous ; for a more abundant supply of nerve force, and more rapidly recurring contrac- tions, would be prejudicial in labour, by bring- ing the uterine walls more constantly and violently into contact with the foetus, and by driving out the blood passing through them so rapidly as to cause dangerous regurgita- tion, or so frequently as to produce foetal asphyxia, through too constant interruption of the placental circulation. * Weber, in the article Muskelbewegung, in Wagner's Handworterbuch. 1856. It is in favour of the views of Wigand, who maintains that uterine action begins at the cervix, and travels upwards, that the cervix receives a larger supply of nerves than the fundus, so that the action may be here first established, and the fundus afterwards ex- cited. But however this may be, it is known that unless all parts of the organ are eventu- ally brought into consent, the labour does not proceed regularly, for if one portion is felt to be hard, and another at the same time soft, irregular action and spurious pains ensue. To ensure, therefore, consentaneous action between- the respective points of the uterine fibre at which the nerves enter its tissue, and to establish and regulate the movements, ap- pear to be the offices of the nerves in relation to the uterine structure. Of the rythmic action of the uterus, and its cause. — The uterus, like the heart and the respiratory muscles, is time-regulated or rythmic in its action. In this action the usual three rythmic periods are noticeable, viz., a period of contraction, a period of re- laxation, and one of repose. The sensible phenomena which accompany the first period are, a gradually increasing and sustained hardness of the uterus, a gradual approach and continuance of suffering, and, after a time, a certain advance of the pre- senting part of the child. These occur- rences do not commence coincidently, but each overtakes the other in the order enu- merated. The phenomena of the second period are, the gradual subsidence of the hardness, the gradual passing away of the pain, and the re- tiring of the presenting part, and these are more nearly coincident than the former. The third period is marked by an absence of all sensible signs. These three periods together constitute the uterine rythm, which observes certain laws, that are in some respects different from those which govern the rythmic action of other parts, as for example, of the circulatory and respiratory organs respectively. In the action of the uterus, 'the repeats take place more slowly than in either of the in- stances just named, although between these two, also, there is a proportionate difference, nearly, or quite as great. The heart's rhythm being quickest, the respiratory rythm slower, and that of the uterus slowest of all. But the rythm of the uterus does not ob- serve a constant or uniform rate. At the commencement of labour, the order of se- quence of the rythmic motion remains for a time tolerably constant ; but as the process advances the rythm becomes modified, so that, like the example of the heart under violent emotion, the interval shortens, while the force and vigour of the contractions increase. It is a matter of great interest to discover, if possible, the determining cause of this rythm ; that which constitutes the regulating as well as the disturbing force. The latter should be rather termed the accelerating UTERUS r- (FUNCTIONS). force, for it is beyond question a healthy ne- cessity which, for the purpose of advancing the process, demands this graduated change of the uterine rythin throughout labour. Rythni plainly does not, like peristaltic action, depend upon the structure of the organ which displays it, for the three examples here taken, viz., respiratory muscles, heart, and uterus, differ from each other materially in composi- tion. The first consists of striated voluntary fibre ; the second of striated involuntary fibre ; the third of unstriated involuntary fibre. It may therefore be concluded, that something else than structure determines rythm. This appears to depend rather upon the manner in which the contractions are evoked, and hence upon the mode of innervation, which is dif- ferent for each organ. The heart and respi- ratory muscles each admit of more easy ob- servation than the uterus, and referring to them for aid in the elucidation of this ques- tion, we find that each of these organs, or sets of organs, is provided with a nervous rythmic centre, upon which its rythm depends, and upon the injury or destruction of which the rythm immediately ceases, — the rythmic centre of respiration being in the medulla ob- longata, and that of the heart in its own pro- per ganglia. Which of these divisions of the nervous system furnishes the rythmic centres of the uterus has not been determined, but from the analogies just quoted, we may select by preference the heart, because its actions most nearly resemble those of the uterus, in being purely involuntary, while the case of the respiratory muscles constitutes an ex- ample of mixed movements wherein volitional can be superadded to unconscious rythmic motion. If therefore the rythmic action of the uterus is regulated in like manner with that of the heart, we must, upon the strength of this analogy, look for its rythmic centres among the sympathetic ganglia which lie nearest to the organ. And this view does not necessarily exclude a certain influence of the spinal nerves over the rythmic action of the uterus. For just as under emotion or bodily excitement both the cardiac and respiratory rythms are accele- rated, so, as labour advances, and more parts become irritated, the uterus appears to receive an addition of nerve force which may be pos- sibly acquired from other and more distant centres than its own proper ganglia. The heart's rythmic centres have been re- garded by some physiologists as so many " magazines " of nerve-force, whence at regu- lated intervals this force is discharged, causing the muscular structure to contract in accord- ance with the rate of supply of the stimulus. The influence of these nerve-centres is best shown by placing a ligature upon them, or by cutting them away. When hindered in their operation by tying, the rythm ceases, though the motor power is not lost. When they are cut away, together with certain portions of the heart, the other portions cease to have rythmic motion, though they may still be 67o artificially excited to repeated single ac- tions.* But an inconstant stimulus thus furnished to the muscular structure being powerless to produce a permanent or tonic contraction, the effect after a short time passes away to be reproduced upon a fresh application of the excitement. In this way rythm, so far as it is dependent upon nervous supply, is ap- parently determined. But in the case of the uterus we observe that the rate of the rythm must be to a cer- tain extent limited by the peculiar nature of the uterine fibre. For this, as already shown, is of a kind which cannot be excited to rapidly repeated action like the heart. In this form of fibre the response to the stimulus is slow, and often does not take place until after the excitant is withdrawn. Hence the meaning of that slow repetition of uterine action which is observed in ordinary labour. When this point is further examined, it will be found that, according to the degree or kind of excitement employed, the uterine rythm may be merely accelerated, br a rythmic may be converted into a more continuous action. The influence of the passage of the child during labour over successive surfaces in quickening uterine action has been already shown. Another example may be drawn from the effects of ergot. When ergot is given by the stomach some time usually elapses before the ergotine mixes with the blood sufficiently to excite the rythmic centres, but that being done, the action is simply augmented, or else occasionally it becomes so violent that the in- tervals are obliterated, and one contraction becomes merged in another, so that an inter- mittent is converted into a continuous uterine action. But that which more certainly demonstrates that the rate of the motions, whether rythmic or constant, is dependent on the kind and ex- tent of irritation, is the variation in the results obtained by different modes of inducing pre- mature labour. If, according to the method of Kiwischr water is injected simply against the cervix, after several repetitions, rythmic action is slowly excited. If the cervix is dis- tended by the introduction of a sponge tent, rythmic action ensues more quickly and cer- tainly. But if the first proceeding is so varied that the water, instead of being merely thrown against the cervix, is introduced between the membranes and the uterine walls for a very short distance, so as gently to effect their sepa- ration from the inner surface of the uterus, labour is induced with greater certainty and speed than in any other way ; but should the separation be carried still further, some such tumultuous form of labour results as ergot pro- duces when acting in the manner just specified. The uterus acting continuously and very ener- getically rather than intermittingly. Influence of the different nervous centres upon the uterus in parturition. — In the present un- settled state of neural physiology, especially in * Paget, Croonian Lecture ; Proceedings of Roy. See. vol. viii. No. xxvi. 1857. x x 2 67G UTERUS AND ITS APPENDAGES. relation to the powers of the different nerve centres, it is scarcely possible to arrive at any satisfactory conclusion regarding the relative degrees of influence which these may be sup- posed to exercise over the movements of the uterus. The marked differences of opinion still existing upon this subject * afford sufficient evidence of the uncertainty of the data upon which definite conclusions can be based. In this uncertainty, however, all points of the nervous system are not equally involved. The amount of influence of the cerebrum upon the act of parturition can be determined with tolerable accuracy. That the uterus is in communication with the brain is proved by the fact that the woman is conscious of the foetal movements, and that she suffers pain when the uterus contracts. Emotion may excite, and may also for a time delay, uterine action. The will cannot operate directly upon the uterus, either in the way of producing, or of restraining its contractions, but a slight in- direct influence may be occasionally perceived, when by voluntary changes of posture, or by the use of those muscles which assist labour, the force of the uterus is slightly increased ; or conversely, when, by carefully restraining all such movements and* actions, this result is avoided. It is further shown by the occurrence of labour in cases of complete paraplegia, and also during states of unconsciousness, induced by anaesthetics, that the uterus contracts while it is withdrawn from all volitional and like cere- bral influences. These several examples serve to show to what extent the contractions of the uterus may be influenced by the cerebrum, and also how that influence may be withdrawn. It is obvious that psychical influences are neither necessary nor accessory to the simple act of labour. They may often be regarded as dis- turbing, but not as regulating forces. Hence the dominant power over the contractions of the uterus, which is exercised during labour, must have its seat in some of those nervous cen- tres that are placed lower than the cerebrum. We may therefore proceed next to inquire what are the attributes which from direct ob- servation and analogical reasoning the uterus may be supposed to derive respectively from the ganglionic and spinal systems, regarded as separate sources of motor power. But here, on account of the intimate manner in which the nerves derived from each of these centres are bound up together, great difficulty arises in distinguishing between the operations of each, and these difficulties can be only in part surmounted. The circumstances which point more par- ticularly to the influence of the ganglionic system will be first considered. The uterus derives a greater proportionate * See Tyler Smith, Parturition and the Principles and Practice of Obstetrics; and Lancet, 1856. Scanzoni, Lehrbuch der Geburtshilfe. Brown- Stquard, Physiology and Pathology. Carpenter, Principles of Human Physiology; and Todd, art. NERVOUS SYSTEM, in this Cyclopedia. supply of nerves from the ganglionic than from the spinal system. This appears from the re- searches of both Snow Beck and Kilian. The actions therefore of those parts or organs having like endowments, which are in other respects also comparable with the uterus, may be here examined. Of all organs the heart is that which most nearly resembles the uterus. It constitutes, after the uterus, the largest hollow muscle. Like the uterus, it acts with rhythm, and, in a certain degree, peristaltically. It continues its contractions, with little, if any, interruption, for a long time after its principal cerebro-spinal connections have been destroyed, as by tying the pneumogastric nerves. It continues to contract rhythmically in many animals for a variable time after death, or when cut out of the body Its contractions are regulated mainly by sympathetic ganglia, while the cerebro-spinal fibres which it receives serve to establish rela- tions between it and other parts. The uterus exhibits many like peculiarities. It acts with rhythm and peristaltically. It continues these actions, in numerous species of animals, for a variable time after death. Even in the human subject, a post-mortem power of contraction seems to be occasionally retained, as in the case of women whose spon- taneous delivery has taken place some time after all evidences of somatic life have ceased.* In these several offices we may conclude that the uterus also, so far as its operations are under the dominion of the nervous system, is, like the heart, chiefly influenced by sympathetic ganglia and nerves. That this is the case is also further shown by the occurrence of delivery under circum- stances in which all spinal influence appears to be abrogated. The following is an ex- ample.f A woman was attacked with paraplegia in the eighth month of pregnancy. JShe had neither sensation nor motion in any part below the umbilicus. No reflex movements what- ever could be produced by tickling the soles of the feet. The faeces passed involuntarily, and the urine was drawn off daily. About the ninth month, her medical attendant, when about to pass the catheter, found a full-grown foetus in the bed (dead). The uterus was con- tracted, and the placenta in the vagina. The * A large number of these cases has been col- lected by Dr. W. H. Wittlinger, " Von der nach dem Tode der Mutter von selbst erfolgenden Geburt," in the Analekten fur die Geburtshulfe, Bd. I. 1849. All cases of post-partum delivery are probably due to one of three causes, viz., to a con- tractile power or irritability remaining in the utems after death, and comparable to that which in vo- luntary muscles produces the now well-known post-mortem cholera movements ; to rigor mortis ; or to the development of gases within the abdo- men or uterus, causing the expulsion of the child by pressure. The first is probably the cause of birth within a few hours, and the last several days, after the death of the mother, and the second of the expulsion of the foetus before decomposition has set in, yet at a later period than can be accounted for upon the first hypothesis. f For this case I am indebted to Mr. Paget. UTERUS — (FUNCTIONS). woman was entirely ignorant of what had occurred. Scanzoni andChaussier relate simi- lar examples of birth taking place notwith- standing complete paralysis of the sensitive and motor functions of the lower half of the body. In Chaussier's case the pressure was occasioned by a hydatid cyst which involved the chord on a level with the first dorsal vertebra.* On the other hand, that the uterine move- ments are also capable of being influenced by spinal fibres, appears from the following con- siderations. Uterine contractions may be ex- cited by the application of cold to the general surface of the body, or by placing the child at the breast; by injecting warm and stimulating fluids into the rectum, and in other like modes. Again : the uterus, under various circum- stances of health and disease, is observed to * Cases of paraplegia have sometimes occurred in which artificial aid appears to have been needed to complete the delivery, as in a case cited by Brachet (Fonctions du Systeme nerveux ganglionaire, p. 266. 1830). By thos"e who contend for a preponderance of spinal influence over labour, such cases are cited in proof. It is said that notwithstanding the com- plete loss of sensation and motion in the extremities, independent reflex operations may still be preserved in the uninjured portion of the chord. But the motions which may be occasionally excited by irri- tating paralysed limbs are " disorderly and pur- poseless," and are in no way comparable with those co-ordinated actions that characterise natural la- bour. Moreover, the argument is entirely inappli- cable to the case cited in the text, in which no reflex action whatever could be produced. It has also been supposed that an essential distinction may be drawn between cases in which the disease is situated high up, and those in which it occupies a lower situation: in the latter cases the portion of chord supposed to furnish spinal nerves to the uterus being involved in the disease, and in the former not. But such conclusions can be of little value until the precise limits of the chord, whence, spinal fibres can be derived to the uterus, have been anatomically determined. (See the account of the origin of these nerves at p. 641.) For like reasons it does not appear that in the present state of neural physiology in relation to the uterus, satisfactory conclusions can always be drawn from experiments upon animals. For "although it might seem probable that in a case of mixed nerves, by destroying the centre or origin of one of the sets, the functions of the other might be left unim- paired ; or by stimulating one of the nerve centres alone, their actions would be exclusivelv called forth, while the rest would remain passive; still, absolute conclusions cannot always be arrived at, even in these ways. For in the latter case, on ac- count of this very intermixture of nerves, whenever wye attempt to stimulate ganglionic centres, or plexuses, we are dealing at the same time with the spinal fibres which pass through them. Or con- trariwise, when we endeavour to destroy extensive tracks of spinal centres, we do not know if the arrest of labour that may follow is not due to the violence which, in most "of these experiments, has caused the death also of the animal within a few hours or days after, rather than to the destruction only of the portion of spine whence uterine fibres are supposed to be derived. In this way, perhaps, we can explain those discordant results of experi- ments, in some of which labour has been arrested, and in others has not apparently been interfered with, so far as uterine action alone is concerned, after greater or less injury or destruction of the chord. 677 or several of the parts just react upon named. Hence it appears that a mutual relationship is established, by virtue of which the uterus may be either the excitor of actions in these parts, or may through them be itself excited to action. And there can be no doubt that the spinal cord is the 'agent through whose reflex operations these several effects are pro- duced. From this evidence it may be concluded that the double supply of nerves answers dif- ferent purposes. That the spinal system fur- nishes nerves for the purpose of bringing into harmonious relations all those organs whose cooperation with the uterus is essential or ac- cessory to various steps of the reproductive process. While the organ deriving also a simi- lar or even larger supply from the ganglionic system, these nerves serve to regulate the functions which the uterus itself is capable of discharging without cooperative aid. In this view the offices of the spinal system, as a system of relations, and of the ganglionic, as a system presiding over the direct acts of the parts which it supplies, may be separately ex- hibited. It is doubtless also a chief office of the ganglionic system to regulate and control the action of the blood-vessels with which the uterus is so largely supplied. What is the exciting cause of labour ? — This question carries us only one stage further in the preceding course of inquiry : and the reply to it will be nearly found in the facts already stated. For if these serve to throw light upon the causes of the rhythmic and peristaltic movements of the uterus, then the conditions which determine the first rhythm and first peristalsis, or, in other words, the beginning of labour, cannot lie very remote from these. Many circumstances may evoke the first rhythm, which being followed by others, labour becomes established. Thus, irritation of in- cident nerves in various parts and organs may so force those sympathies with the uterus which, for other uses, are established by the spinal system of nerves, as to bring on an un- natural and premature form of labour ; — but this is not the present question. The determining causes of natural labour can be only satisfactorily sought among that class of phenomena which causes the separa- tion of the ripe fruit from the stem which bears it : in a perfecting, namely, of the fruit or product of conception, so that it becomes fitted for an independent existence, and as a step preparatory to this, in a gradual meta- morphosis of those tissues which, having served for a time the purpose of connecting the two together, are now no longer required by either. This connecting medium in the human subject is the decidua, which lines the whole uterus. Its metamorphoses during preg- nancy have been described. Already as early as the middle of that period, the preparation has begun for a new tissue, which, after labour, is to reconstruct the lining membrane. The old attenuating and perishing decidua, now no longer needed, except at the spot where it x x 3 678 UTERUS AND ITS APPENDAGES. covers the placenta, loses by degrees the cha- racter of active vitality, and its tissues are con- verted into molecular fat. Other and corresponding changes, of which an account will be hereafter given (see PLA- CENTA), occur in those structures in which the foetal blood circulates. The profusely de- veloped capillaries which ramify within the villi during the early and middle periods of gestation begin to suffer retrogression as the time of separation approaches, and the foetal blood flows in more simple and relatively fewer channels, while, not (infrequently, entire villi become obliterated by calcification. While these changes are proceeding in the temporary structures that serve to connect the fetus with the uterus, structures which begin in part, at least, to become effete, even before the offices for which they are formed have been fully carried out, — the tissues which are to be employed in the process of expulsion are as yet only ripening into full strength, although they also, in turn, are about to suf- fer a like retrogression, but not until the ob- ject of their formation has been accomplished. The contractile fibre, which constitutes the principal portion of the uterine tissue, has gradually, during pregnancy, advanced to that more complete form which is reached com- monly about the sixth month. From this pe- riod probably no new development of muscular fibre takes place, although that which is already formed appears to increase somewhat in size and power. It constitutes now a contractile tissue, capable of exerting great expulsive force. How easily, and in how many ways, the contractile power may be evoked, has been already shown. It is probable that by the series of metamorphoses already enumerated as occurring in the parts which connect the foetus with the uterus, the entire ovum becomes gradually placed in the position of a foreign body within that organ ; a position which may be compared to that of the food within the alimentary canal. And just as the food is propelled onwards, peristaltically, by irritation of successive portions of the containing sur- faces, until, with the subsequent cooperation of muscles acting under the dominion of the spinal cord, it becomes finally ejected ; so the ovum is itself apparently the excitor of those first peristalses in the uterus which initiate labour. How these become coordinated and established, and how the rhythmic periods are probably determined, has been already con- sidered, as well as the means by which, during the further advances of the child over succes- sive portions of the generative track, other nerve and motor forces are added to those with which the process commenced. ABiNORMAL ANATOMY OF THE UTERUS. A. Defective development. — Imperfect or defective development of the uterus may oc- cur under two circumstances. There may be either an original defect in its organisation, arising from a failure of growth or imperfect formation of those portions of the generative canal out of which the uterus is developed ; or else the organ, having been regularly formed during embryonic and foetal life, may not have proceeded in its development, but may have retained the infantile character after the usual age of puberty has arrived and 1st Class. Congenital defects. — Defects of this class may affect the uterus alone, or may be conjoined with corresponding imperfections of other organs. In order that their nature and origin, as well as the possibility of their occurrence, independently of any malforma- tions of the other reproductive organs, may be clearly understood, it is necessary to remem- ber the mode in which the uterus is originally constructed. Formed by the coalescence of Fig. 460. The entire internal generative organs, from a foetus of three months. (After J. Midler x 8.) a, uterus ; b, round ligaments ; c, Fallopian tubes; d, ovaries ; e, remains of Wolffian bodies. the inferior extremities of the ducts of Miil- ler*, the uterus will be materially modified in its construction according to the degree of perfection of those ducts, as well as by the amount of union which has taken place at their lower terminations. Taking these particulars as affording a basis for classification the malformations of the uterus which are dependent upon original vices of formation may be arranged in four groups, viz. : — Group 1 . The ducts of Miiller being both imperfect or undeveloped, there results a more or less complete absence of the uterus. The examples of total absence of the uterus which have been recorded are probably cases in which the rudiments exist, but have been overlooked, on account of their slight deve- lopment ; for generally there may be traced a more or less distinct fold of peritoneum ly- ing behind the bladder and representing the broad ligament, within which are found some indications of a uterus. These rudiments consist of two uterine cornua, either conjoined at their lower extremities, or remaining sepa- rate in their whole course. They usually oc- cur under the form of two hollow rounded cords or bands of uterine tissue, extending upwards towards the ovaries, and united per- haps at the usual seat of the uterus by cellu- lar tissue, with which some uterine fibres are intermixed. Sometimes one or two little masses of uterine tissue are found. These are either solid, or they contain a small cavity * See p. 642. UTERUS — (ABNORMAL ANATOMY). 679 lined by mucous membrane. This constitutes the condition designated by Mayer the uterus bipartltus. The concomitants of this condition may be a short vaginal cul-de-sac, together with rudimental Fallopian tubes, and perhaps well developed ovaries. In the latter case the external organs may be well formed, and there may be no deficiency of sexual cnarac- ter, or the vagina may be entirely wanting. The coexistence of this rudimental uterus with ovaries well developed is easily ex- plained. For the ovary is formed out of a separate portion of blastema from that from which the Wolffian bodies and excretory duct of the generative apparatus are developed, jig. 400. and 416., so that the failure in growth o£ the one does not necessarily involve a cor- responding defect in the other. Group II. If one uterine cornu retains the imperfect condition last described, while the second undergoes development, the one- horned uterus or uterus unicornis is produced. So that the organ here consists of a developed and an undeveloped half combined. The developed uterine horn may be either the left or the right. It then consists of a cylindrical or fusiform canal or body, curved outwardly in the form of an arch which ex- hibits various degrees of deflection from the meridian. To its upper extremity is usually attached a tube leading to the seat of a well- formed ovary. The second or undeveloped cornu, with its tube, is not always entirely deficient ; but there often exists a rudiment in connexion with the developed horn, which, according to the degree of malformation, is either solid or hollow, or is traversed by a canal opening into the cervix of the developed half. In the case of the uterus unicornis, notwith- standing the imperfection of one uterine half, both ovaries may be found alike developed. The type of this condition of uterus exists as a normal formation in the class aves, where one side only of the generative apparatus proceeds in its growth, and the other remains undeveloped from an early period of foetal life.* Group III. If, instead of an unsymmetrical growth of the two uterine cornua, such as occurs in the last example, both sides are alike developed, yet without any, or with only an imperfect, junction of their lateral borders there is produced a uterus bicornis, falsely termed a double uterus (uterus du- plex). Here however there is no evidence of plurality, or true duplicity of the uterus, but only a deficiency of that union of the two separately formed halves by whose subsequent conjunction the organ is normally constituted. This conjunction should naturally com- mence from the level of the point of attach- ment of the round ligaments, and the varia- tions in the degree of malformation will be according to the height at which the union of the uterine halves stops short of that point. The highest degree of malformation in this group, or the greatest departure from the normal form, is that in which the two uterine halves do not coalesce at all, but remain com- pletely divided in their whole extent. This happens very rarely, and is co-existent with other malformations, such as fissure of the abdominal and pelvic walls. The division is here so complete that certain of the pelvic or abdominal viscera may occupy the space be- tween the two uterine halves. In the next degree of this kind of deformity a horizontal commissure occupies the angle in which the two uterine halves meet, and serves to unite them together (fig. 46 1 .). The Fig. 461. The body of the uterus divided into two halves, which are united at the cervix by a horizontal commissure representing the fundus. The os uteri and vagina are double. (After Busch.} horizontal commissure is composed, like the cornua, of uterine tissue, and represents the fundus uteri. According to the height at which it is placed, the external form of the uterus approaches or recedes from the normal type. Kokitansky* has pointed out how the situation of this commissure affects the angle in which the two cornua meet, and conse- Fig. 462. The vagina, os uteri, and cervix, single. (After Busch.) The body of the uterus forming two cornua, •which are still nearly horizontal, but are united by a commissure at a higher point than in fig. 401. quently the relative mutual position of the two uterine halves. The nearer the point of co- * See Fallopian tube, p. 613. Loc. cit. p. 274. x x 4 680 UTERUS AND ITS APPENDAGES. alescence of the two halves approaches to the external orifice, the more obtuse will be the angle at which their junction takes place, and the more extensive will be the fissure (fig. 461.). On the other hand the higher the point of union, the more acute will be their angle. This becomes obvious in the lesser degrees of deformity represented in figsAQZ. and 463. In j%. 462., although the commissure is placed at a higher point than mfig. 461., so as to be much further removed from the external os, there is still a considerable separation of the two cornua, and their direction is still mainly horizontal ; but in fig. 463., where a more per- fect coalescence of the two halves has taken Fig. 463. The cornua more completely united externally, and the two halves becoming more nearly parallel, (Ad Nat.) The body is still divided by an internal septum which descends from the commissure as far as the commencement of the cervix, where it ends in a thin falciform edge. place, and, consequently, where the com- missure approaches nearer to the points of attachment of the Fallopian tubes and round ligaments, the angle has become so much smaller, that the two halves begin to lie nearly parallel with one another, and the horns, or ununited portions, exhibit only a slight di- vergence. In this, as well as in the following group of malformations, there often proceeds from the commissure an internal septum which descends to a variable depth, and exercises a correspond- ing influence upon the separation of the two halves. In cases where the commissure representing the funclus lies very low, there may be no septum, and a single cervix con- ducts into two uterine halves which lie right and left of it. In cases where the fundus is higher, if the septum extends downwards only in a slight degree, as in jigs. 462. and 464., the cervix is still common to both sides of the uterus. Where the septum begins to divide the cervix, as in./zg. 463., the separation of the two uterine halves is more complete, but there is still a common os externum, leading to the two canals. The highest de- gree of division, and consequently lowest type of structure, is that in which the septum ex- tends not only through the cervix, but even to the extremity of the vagina, dividing the latter, fig. 461., together with the hymen in the virgin state, so that there are two com- plete canals leading to corresponding uterine halves. Group IV. In this group the external form of the uterus differs but little from the normal character. The breadth of the organ, especially between the points of entrance of the Fallopian tubes, is usually greater, and the fundus, though arched, is more shallow than usual. Here also a slight notch, extending into a shallow furrow, running along the posterior uterine wall, may indicate the seat of that in- ternal vertical septum which more or less completely divides the uterine cavity into two halves, and constitutes the uterus bilocularis (fig. 464.). Fig. 464. The body of the uterus showing only a slight indenta- tion externally. (After JBusch.~) An internal septum c, divides it into two loculi, a and b. The cervix, d, is single. The extent of this septum, and conse- quently the more or less perfect formation of two separate loculi, exhibits the same varieties as in the former group. The par- tition may stop short at the cervix, or ex- tend in rare cases completely through that canal, and even divide the vagina. Where the septum is rudimental, and extends only to the cervix, the lower free border is usually thin and falciform (fig. 463.), having its concavity directed forwards, the lower extremity being that which is connected with the posterior uterine wall. These several deviations from the normal form of the uterus will more or less in- fluence the manner of performance of all its functions. The acts of menstruation and insemination are those perhaps which are the least dis- turbed. Regarding this former function, wherever the ovaries are perfect and a chan- nel exists for the menstrual fluid, as, for in- stance, in the one-horned uterus, the external escape will occur as usual ; but in the case of atresia of the vagina, and in those examples of a hollow rudimental uterus, the menstrual blood collects, and distending the closed sac forms there a haematometra.* Where the parts representing the uterus are entirely solid, * See p. 697. UTERUS — (ABNORMAL ANATOMY). the menstrual molimen may not be thereby hindered, but the escape of blood can only take place, if at all, from some unsuitable situation producing the so-called menses devii, or vicarious menstruation. Regarding the influence of these malforma- tions upon insemination and a resulting im- pregnation, much of necessity depends upon the condition of the vagina ; for this canal may be in so rudimental a state as not to admit of intromission. The canal leading to the ovary also may be either open or closed. In the case of the rudimental tube attached to one side of a single developed cornu, the passage may open into the cervix of the de- veloped half, and thus a channel for the se- minal fluid will be established in connexion with an ovary that may be normally formed, and thus impregnation and gestation, even in an undeveloped cornu, is possible.* Greater difficulties and considerable danger indeed to life arise, during the progress of gestation, in the higher deformities of this class. Pregnancy in a rudimental horn would probably be attended by rupture and fatal haemorrhage at an early period, as happened in Rokitansky's case quoted in the last note, and as usually occur also in the not dissimilar example of ordinary tubal gestation. But even in the case of pregnancy occurring in the developed horn of a uterus unicornis, the undeveloped half will exercise a marked in- fluence upon the progress of gestation, by impeding the due expansion of the developed side; while the supply of blood usually fur- nished in pregnancy being here provided by only one set of vessels, the course of the pregnancy will probably suffer in a corre- sponding degree. 681 In the cases of the uterus bicornis and bilocularis, either horn, or either uterine half, may become separately or alternately the seat of gestation, or pregnancy may proceed simul- taneously in both. There is even reason to suppose that twins have been developed in one half, and also that superfuetation has obtained in such a condition of parts. In those cases where the vagina is parti- tioned into two canals impregnation may take place more frequently or even exclusively on one side, in consequence of the one channel or half being more favourably formed for in- tromission than the other. Regarding the influence which these ano- malies may have over the last office of the uterus, viz. parturition, it is only necessary to observe that in both the uterus" bicornis and bilocularis the organ will be deprived of the advantageous use of the fundus, which so ma- terially aids expulsion in a normally formed uterus, while in the case of the uterus uni- cornis and bicornis, where the impregnated half usually forms an acute, or even nearly a ri^ht angle with the axis of the body, the effect, as Rokitansky has shown *, will be, that during the act of parturition the axis of the impregnated half meeting with the vaginal axis in an obtuse angle, the direction of the uterine force and of the expulsion of the foetus will cross the axis of the pelvis, and fall upon the pelvic parietes that lie opposite to the vertex of the pregnant half of the wombv and thus the act of parturition will be rendered correspondingly difficult in such cases. 2nd Class. Defective development after birth. The pre-pubertal uterus. — The or- dinary age of puberty may have arrived and Fig. 465. The uterus undeveloped after the ordinary period of puberty has arrived. The cavities of the body and cervix are laid open. (Ad Nat.) o, cavity of the body retaining the triangular form and the lines or rugae characteristic of infancy ; b, the cervix, the extent of which is indicated by the penniform rugae ; c, anterior lip of the cervix ; d, ovaries ; those of tbt urinarj bladder. S..;1: a Dowfidoa • .,;. KSCQT . oder dilatation ;• tbe > •":;-.-«:.,;:. however 15 more com- h :.:. increase in At Aiek- parietes. The atrophy of tbe uterine walls which is accompanied by of tbe cavity, is distinguished as and that which occurs in may be combined , of its canal, and is often »sition or morbid line body or its appendages. i> of far more frequent oc- B atrophy. According as dae entire uterus or only of its parts, the organ either presents figure but upon a larger scale, or dbe a greater preponderance is given to one that the uterus becomes malformed. Hv>.rf; •:•:,;> ; •' the entire uterus commonly results trout frequent pregnancy, from the _•- ... f : ; t " Durs, ;-r from accun tioi oi •kid within the cavity. In the latter cases tbe uterine walls may acquire the same thick- ness as in pregnancy — and the hypertrophy also to the same cause, viz. to a deve- of smooth muscular fibre, such as takes place in the gravid uterus. Hypertrophy of the cervix is most fre- quently observed in extreme prolapsus, of which" in the chronic stage it appears to :>•: :-. constant sequence, Hi-r the hyper- laces usually a uniform enlarge- both lips, which form together "an annular tumour divided transversely by a wide os taacae.. fa. 472. Pig. 47 But tbe cervix may become hypertrophied in tbe longitudinal direction also. From this there results a remarkable elongation of tbe uterine neck, which may protrude to a con- siderable distance beyond the vulva without a corresponding degree of displacement or de- scent of the body of the uterus. In the ac- companying illustration, j%. 473., the manner of growth of the elongated cervix is shown. The body of the organ being only partially displaced, a gradual addition to the length oJ[ J%. 473. Elongation rf the cervix vteri from longitudinal hy- pertrophy. (Ad JT«at) f, ftradus; io, internal os uteri; cc, cervix; TO, vaginal walls. the neck occurs until the vaginal portion pro- trudes at the vulva. The canal of the cervix may now measure several inches in length. By degrees the protruded part undergoes in addi- tion the concentric and excentric hypertrophy which is common to all cases of procidentia, and the lips gradually acquire the same ap- pearance as in^/zg. 472. Among tbe anomalies of size may also be included those examples of imperfect involu- tion of the uterus after pregnancy, in which tbe organ retains for several months the or- dinary size characteristic of it shortly after labour. Pathological conditions of the separate tissues ofthe uterus. — Reserving for future notice the affections of the gravid uterus, those morbid states which are observed in the unimpreg- nated organ will be at present considered. These may be divided into such as belong to (1) the peritoneum; (2) tbe subperitoueal tissue; (3) the parenchyma; and (4) tbe mucous lining of the uterus. 1. Pathological conditions of the peritoneal coat. a. The external position of the peritoneal coat, and tbe small amount which it con- tributes to the bulk of the uterus, combine to 688 UTERUS AND ITS APPENDAGES. render the morbid conditions of this coat, re- garded singly, of less pathological importance than the abnormal states of the other tissues. The pathological conditions of the serous coat are chiefly those of acute or chonic metroperi- tonitis, terminating often in exudative processes and the subsequent formation of adhesions be- tween those portions of the uterus which are invested by peritoneum and adjacent struc- tures, such as the Fallopian tubes, ovaries, fig. 420., small intestines, and the like. These adhesions are occasionally so exten- sive as to affect the figure of the uterus, and in most instances they deprive it of its natural mo- bility, and impede or destroy the functions of the parts or organs appended to it, so that an abiding sterility frequently results. The ova- ries becoming invested by a capsule of false membrane, are tied down and atrophied, while the tubes lose their power of motion or their canals become obliterated. The uterine peritoneum is sometimes alone affected, while the appendages escape. If the inflammation has not proceeded to the form- ation of bands of adhesion, there may result only some slight processes of false membrane which remain and fringe the surface of the organ. These little fringes or processes, con- sisting of delicate folds of membrane, often contain vessels which are easily injected. The peritoneum suffers considerable dis- tension with correlative hypertrophy in the case of tumours which project from the outer surface of the uterus. These become inva- riably covered by an extension of the peri- toneum, which is especially strong about the base of the peduncle occasionally acquired by such tumours. 2. Pathological conditions of the sub-peri- toneal fibrous tissue. a. Perimetritis. Partial chronic wetrltis. Peri-uterine phlegmon. Retro-uterine tumours. — The subperitoneal fibrous tissue which con- nects the peritoneum with the uterine sub- stance, like the peritoneal coat itself, is subject to inflammation. In those situations where the union of the outer and middle coats of the uterus is very intimate, the distinction be- tween a peritoneal and a subperitoneal inflam- mation may not be possible, but where this connexion is very loose, and is effected by the interposition of a lax fibrous tissue, inflamma- tion may apparently have an independent seat without affecting at all, or with only a par- tial inclusion of the uterine parenchyma, and sometimes of its peritoneal investment. The term "peri-uterine" has been employed by some authors*, with a view perhaps of avoiding confusion, though at the cost of a solecism, to distinguish these affections from others commonly termed perimetrial. In this article, however, inflammation of the subpe- ritoneal fibrous tissue will be designated peri- itisy while inflammation of the peritoneum * Monat, Observation Medicale (Gazette des Hopitaux, 1850.) Bernutz et Goupil. Recherches Cliniques sur les Phlegmons peri-ute'rines. chives Ge'nerales de Medecine. Mars 1857.) (Ar- itself, which some include in the latter term, is distinguished as metro-peritonitis. Perimetritis consists in an acute, or more often a chronic inflammation of the tissue, which loosely attaches the peritoneum form- ing the base of the broad ligament to the proper substance of the neck and lower por- tion of the body of the uterus. The relation of the peritoneum and of the loose fibrous tissue surrounding the cervix uteri have been described at page 631., where also attention was called to the peculiar lax tissue of this kind which unites the posterior cervical wall with the portion of peritoneum forming the retro-ute- rine pouch (fig. 433. G.). Here, particularly, this inflammatory affection has its seat, although it occasionally extends around the sides of the cervix, so as partially to encircle that part, or more rarely it may involve only the fibrous tissue connecting the anterior cervical wall with the posterior surface of the bladder (fig. 426. b b, and fig. 433. F.). The anatomical conditions of these peri- metrial inflammations are deep congestion of the vessels, accompanied by serous, and occasionally by sanguineous, and possibly fibrinous infiltration of the loose tissue of this part, which, on account of its extreme laxity, readily admits of a great degree of distension. In this way is rapidly formed a tumour which almost invariably occupies the space between the peritoneum and the posterior wall of the uterus, at the point where the body joins the cervix (retro-uterine tumour). The recognition of such a tumour or swell- ing during life, by physical signs, is not difficult. The finger introduced into the vagina, so that its extremity reaches the point of reflexion of the posterior wall of that canal forwards on to the uterine neck, discovers, just above this spot, a hard or semi-elastic projection, which seems to grow out of the cervix just at its point of junction with the body of the uterus. The surface of the tumour towards the rec- tum, upon which it encroaches, is convex, and is either smooth or irregularly nodulated, while between the tumour and the neck of the uterus is usually perceived a notch more or less deep, and comparable in form to that which separates the body from the neck of an ordinary retort. Hence this condition may easily be mistaken for the retorted uterus, which it closely resembles in many particu- lars. The surface of the tumour is exquisitely tender, while the adjacent uterine structures are free from tenderness. The comparative frequency of this affec- tion *, and the constant and severe suffering which result from it, especially in married women, in whom it is usually found, may justify here a brief exposition of the peculiar anatomical condition and relation of parts which appear to me to conduce to its production. From the view of the pelvic viscera given in * I believe that it is often confounded not only with retroflexion, but also with retroversion, fibrous tumour, and hypertrophy of the posterior uterine wall, and that hence the frequency of its occur- rence has not been commonly recognised. UTERUS— (ABNORMAL ANAT«-M\ ). (Jig. 433.) it will be seen, that while the normal cervix projects obliquely into the upper part of the vagina, the fbrnix or blind extremity of that canal forms the actual termination of the tube, so that this arrangement, while it tends materially to the preservation of the os and cervix uteri from injury during congress, at the same time exposes the cul de sac of the vagina to a certain amount of pressure, which various circumstances, such as relative short- ness of the vagina and other obvious condi- tions, may render injurious. But exactly over this spot lies the mass of lax fibrous tissue in question, the meshes of which become easily infiltrated under inflammation by serous or fibrinous fluids supplied by the vessels, which sections of this region show to be so abundant in the neighbourhood. ( Fig. 429.) Perimetrial inflammation occasionally reaches the suppurative stage, and in this way are formed 5»ome of those abscesses which burst through the cervix, or form collections of matter between the folds of the broad liga- ment. 3. Pathological conditions of the muscular or proper coat. a. Diminished and increased consistence of the uterine substance, although generally re- sulting from obvious morbid processes, is yet sometimes found without any apparent dis- ease of the tissue. Diminished consistence may be found in various degrees, from a slight friability or softness to a nearly complete pulpiness (inar- ciditas). In these cases the texture of the uterus may be pale and exsanguine, or in a state of tiyperaemia, with occasionally apo- plectic effusion. Rokitansky associates the latter condition with thickening, and some- times ossification of the uterine arteries. b. Parenchymatous inflammation of the uterus. Metritis. Mctritu parenchymatosa. — Inflamma- tion of the substance of the uterus, which in the puerperal state is so commonly fatal, seldom leads to death in the unimpregnated. Hence opportunities for investigating the ana- tomical condition of the organ in the non- gravid state under conditions of inflammation are of comparatively rare occurrence. From such opportunities, however, aided by what may be observed during life, the following may be concluded as to the changes which inflammation produces in the muscular and fibrous coat. Under acute parenchymatous inflammation the whole organ becomes increased in bulk, and at the same time redder and softer. On section blood flows freely from the divided vessels, and the tissues are found permeated by serous infiltration. Sometimes the highly congested ve-seLs have in parts given way, and ecchymoses or larger apoplectic collections have resulted. If no commensurate resorption of these effusions takes place the organ continues of abnormal size. This is more particularly ob- servable when a portion of the uterus, as the body or cervix, has been repeatedly inflamed. The latter, especially, remains enlarged. The Supp. os tincae is patulous, and one or both lips of the cervix present an cedeinatous hardness, and occupy a larger space than usual in the fornix of the vagina. Occasionally inflammation of the uterine parenchyma reaches the suppurative stage, resulting in collections of matter which may escape into the peritoneum between the folds of the broad ligament, or externally by the vagina or rectum. Chronic inflammation produces likewise a general enlargement of the uterus, but more commonly the cervix is principally or exclu- sively involved, and the resulting enlargement is especially observable in its vaginal portion, the lips of which become increased in breadth, or elongated and prominent. When chronic inflammation affects, on the other hand, the parenchyma of the body of the uterus chiefly, the walls of this part become thickened and indurated, while the cavity undergoes enlargement such as is exhi- bited by the ventricles in excentric hypertro- phy of the heart. Under chronic inflammation the uterine tissue becomes indurated, so that upon section it grates beneath the knife. This induration is occasioned chiefly by hypertro- phy of the fibrous element of this coat of the uterus. c. Fibroid. Tumor fibrosus uteri. Fibro- muscufar tumour. Hard fleshy tubercle of the uterus (Baillie). — These and numerous other titles have been employed by different authors to designate a form of degeneration of the uterine tissue which is so common that, ac- cording to the often quoted calculations of Bayle, it may be found in every fifth case of women who die after the age of thirty-five.* Fibroid of the uterus has for its basis the same structure as fibrous tumours in general -J- The surface of a section presents to the naked eye a peculiar mottled appearance, caused by the presence of numerous white lustrous bands intersecting in all directions a more homogeneous basis substance, which in these uterine formations has always a greyish or light brown colour, the latter being especially distinct in spirit preparations. The difference between these two, however, is more appa- rent than real, consisting, as Paget suggests, rather in the mode of arrangement than in an actual differentiation of the component struc- tures. These consist chiefly of very slender filaments of fibrous tissue " undulating or crooked," and exhibiting various degrees of development in different specimens, being in some large and wavy, and in others very short, and often intermixed with cUoblasts and nu- clei. Along with this fibrous basis is found a variable amount of smooth muscular fibre, which in some cases, especially in the polypi hereafter noticed, forms the chief bulk of the * Dr. West has furnished some interesting sta- tistics upon this subject. (Lectures on the Diseases of Women, Ft. i. p. '277. 1856.) | For an account of these see Paget's Surgical Pathology, Vol. II. LectV. ; and also for those of the uterus, Bidder, in Walter ueber firbrose Kb'rper der Gebarmutter. Y Y 690 UTERUS AND ITS APPENDAGES. mass, so that a muscular rather than a fibrous tissue results. A small quantity of elastic fibre is also occasionally found in these ute- rine formations. Fig. 474. Section of fibroid tumour of the uterus. (Ad J¥at.) The structural variations observable in fibroid of the uterus, are dependent chiefly upon the peculiarities in arrangement of these component elements. In the more dense formations, the white shining fibrous bands enclosing little pellets of the browner sub- stance, form numerous small compact masses, which are again closely united together by a somewhat looser fibrous tissue that serves to combine the whole into lobes or lobules, va- rying in size from a pea to that of a man's head. The variation in density of these masses depends, further, upon their vascula- rity. In the softer kinds, bloodvessels that may be injected permeate the mass, running along the bands and layers of fibrous tissue connecting the lobules. Such tumours are sometimes of a deep red colour. The denser masses, on the other hand, are apparently nearly bloodless ; at least, injections cannot be made to penetrate them. The different configurations which these masses of uterine fibroid assume, appear to depend in a great measure upon accidental conditions. In this particular three varieties may be noticed. 1st var. Interstitial fibroid. — The mass here forms a growth, sometimes of immense size, but still contained within the proper boundaries of the organ, occupying one or other uterine wall, but neither encroaching upon the uterine cavity, nor protruding ex- ternally. Such is the case represented in •fig. 475., in which the external appearances were those of the ordinary gravid uterus in the seventh month. Such masses appear oc- casionally at their periphery to merge gra- dually into the healthy tissues of the uterus, but more commonly there exists a distinct boundary formed by loose cellular tissue with which the tumour is so lightly connected that it may be easily detached and turned out of its investing capsule (fig. 475 ). 475. Interstitial fibroid of the uterus. (Ad Nat. ) The tumour is formed in the substance of the posterior wall, which is so attenuated at one spot as to be nearly broken through. The cavity of the uterus is shown in the lower part of the figure un- altered in size. 2nd var. Snbperitoneal fibroid. — In this variety the fibroid mass or masses protrude from the external surface of the uterus. Here one or several round or oval tumours are formed which seem to grow out of the uterine substance by a narrower or broader base, or they remain attached to it by a peduncle. These masses consist entirely of fibroid, having either simply an investment of perito- neum, or beneath that also, in many instances, a layer more or less thick of uterine sub- stance which is usually laminated, so that a capsule composed of the natural tissues of the uterus is formed around the tumour (fig. 476.). 3rd var. Sub-mucous fibroid. — In this va- riety the fibroid mass quits its bed in the uterine walls, and projects into the cavity of the uterus ; it becomes covered by an exten- sion of the lining membrane of the uterus, and sometimes also beneath this by a layer of healthy uterine tissue. These tumours, when they possess a peduncle, constitute the fibroid polypi of the uterus. A distinction has been made in these po- lypi between such as form continuous out- growths from the substance of the uterus, and those in which the polypous mass forms a discontinuous tumour, connected only by a narrow stem of mucous and muscular tissue. The original position of the fibroid growth in the uterine walls, whether in the middle or nearer to their inner or outer surfaces, proba- bly determines, in a great measure, the direc- tion and form which these growths ultimately take, and is consequently productive of the three varieties above noted. The different forms which fibroid assumes are in accordance with these varieties of po- UTERUS — (ABNORMAL ANATOMY). sition. Fibroid growths retained within the uterine walls, are at first almost invariably spherical, but in course of growth become ovate or flattened. Those which project from the outer surface are usually nearly round, while the polypi of the cavity, and those which extend into the vagina, are pyriform, and possess longer or shorter peduncles. The greater part proceed from the fund us, com- paratively few from the walls of the body, and scarcely any of this kind from the cervix. The latter are usually of a more spongy or cellular character than the former, which con- sist of a denser fibrous tissue. The power of gro\\th of fibroid tumours appears to be nearly unlimited. The known extremes in such cases are, in point of num- ber, from one to forty ; and in respect of weight, from a few grains to seventy pounds. Fibroid exercises a considerable influence upon the form and position of the uterus. Tumours within, or external to it, change the position of the organ in various ways, pro- ducing elevation, prolapsus, lateral obliquity, and especially retroversion, according to the seat which they occupy. Polypi distend the cavity of the body and cervix, and the os uteri, and sometimes produce prolapsus and inversion of the uterus. The influence of fibroid upon the thickness of the uterine walls is also considerable. Ge- nerally a marked hypertrophy, equal some- times to that of pregnancy, takes place, while in parts a thinning of the walls occurs. The latter is especially observable in cases where the tumours are numerous, as in Jig. 476. These sometimes appear to grow at the ex- pense of the whole uterine substance, so that the original organ is \vith difficulty discovered among the hypertrophied mass. Fig. 476. The uterus surrounded by outgrowths of fibroid which hate pushed the peritoneum before them, several having become pedunculated. (Ad J\~at. ) The uterus, at the expense of whose tissues the tumours are formed, can scarcely be discovered in the midst of the mass. Important consecutive changes take place during the process of growth of fibroid. So long as the structure retains its original hard- ness, the increase is comparatively slow, con- 691 sisting in a simple and uniform multiplication of the elements already described. Occasion- ally an increase of density is produced by cal- cification of certain portions of the mass, and in this way the so-called bony tumours of the uterus are formed. Or, on the other hand, under rapid growth, the tumour may become softer, in consequence of serous infiltration into its tissues ; the fluid occasionally collect- ing in the centre of the tumour and forming there a species of dropsy. Or, a process of inflammation being set up, suppuration, and sometimes sloughing, result. In the more vascular fibroids the vessels may dilate and burst, and the tumour then becomes infiltrated with extravasated blood. It has been doubted whether fibroid ever undergoes absorption. I have reason to think, from occasionally wit- nessing a marked diminution in bulk, that this may sometimes occur. The explanation of this is indeed easy when the mass of the tumour consists of hypertrophied muscular tissue, which in such cases has been found to undergo fatty degeneration, and so its disper- sion may be effected. Subperitoneal and interstitial fibroid, when extensive, interferes with pregnancy, and also renders labour difficult or perilous, by weaken- ing the expulsive power of the uterus and pre- disposing the organ to rupture. Submucous fibroid, in the form of polypi, may prevent impregnation or shorten gestation. In the unimpregnated uterus, all forms, but especially the submucous and interstitial, are apt to be accompanied by severe recurrent haemorrhage, producing excessive anaemia and occasionally death. Lastly, it may be observed, in reference to tumours which are commonly termed polypi, that the present state of pathology demands a separation of these, according to their struc- tural differences, such as has long been esta- blished, upon a similar basis, among those objects of the animal kingdom whose sup- posed resemblance, distant indeed, and at the best fanciful, has given a name to this form of tumour. For, as in that prototypal group of animal forms, once termed polypi, three widely separated classes at least are now known to have been combined, so those pathological for- mations, which are still familiarly termed po- lypi, exhibit a more than equal number of va- rieties, each marked by distinct differences of structure. These may be distinguished as the fibrous, including the cellular, which are com- posed of a looser fibrous tissue ; the muscular; the mucous, also frequently containing much fibrous tissue, and the cancerous or malignant polypi. And to these have been added the so-called Jibrinous or blood polypi. The fibrous polypus has been already de- scribed, and the second, or muscular, may here also be classed with it, as having its origin in the middle coat of the uterus, but consisting of muscular rather than of fibrous tissue. These muscular polypi are comparatively rare. Their structure, as exhibited in the ac- companying Jig. 477., is precisely that of the proper muscular coat of the uterus. Y Y 2 692 UTERUS AND ITS APPENDAGES. m$w W[lf •*? Section of a polypus formed of the muscular tissue of the uterus. (After Wedl.} The fibres, arranged in bundles, run in different directions. At a a, they have been divided trans- versely, and in other parts obliquely. Compare with/0. 436. The malignant polypi, and those which are formed of hypertrophied mucous structure, belong to another category, and will be de- scribed hereafter. 4. Pathological conditions of the mucous coat. — a. First under this head may be noticed simple hypertrophy of the uterine mucous membrane, followed often by a partial shed- ding of that structure in the form of the so- called Dysmenorrhceal membrane. — The term men- strual decidua would probably form a more appropriate title for these structures, which consist of a greater or less thickness of the mucous membrane lining the uterus, differing in no respect from that membrane in its ordi- nary condition *, except in the one particular, that it has undergone a certain degree of hypertrophy. (Fig. 443.) The hypertrophies which the mucous membrane of the uterus undergoes in various circumstances form a most interesting subject for study, but all of them are not pathological. The most familiar example of normal hypertrophy of the uterine mucous membrane is that which occurs in ordinary pregnancy. Here, no sooner does the uterus begin to enlarge, than the mucous lining also expands, arid its tissues become opened up by an in- creased flow of blood, and a consequent rapid development of the simple elements composing this structure. This hypertrophy occurs in every pregnancy where the ovum enters the uterus. But it also happens very generally in those cases where the ovum never enters the uterus at all, but is developed externally to that cavity (extra-uterine gesta tion). Here a most perfect decidua is usually found lining the uterus. The exceptions are few in which the uterine mucous membrane, under these circumstances, does not exhibit anjr increase of thickness, but retains or nearly so, its ordinary characters * See on the structure of the uterine mucous membrane, p. 635. of this article. But a state of pregnancy is -not necessary to produce evolution of the uterine lining, for this may occur when the body of the uterus is enlarged from other causes. Thus, in an example in my possession of uterine fibroid, in which the body of the uterus has undergone the hypertrophy already described (p. 491.), as common in that state, the hypertrophy has extended to the mucous membrane, so that the uterine cavity, which had also been occupied by one of these tumours, exhibits a delicate decidual lining. The decidual membranes occasionally cast off from the uterus under circumstances of dysmenorrhcea, consist of fragments, or, more rarely, of entire membranes forming casts of the uterine cavity. The structure of all these is nearly similar, and they differ chiefly in the greater or less thickness of membrane de- tached. All present upon their inner surface the peculiar cribriform markings already de- scribed as constituting the orifices of the uterine glands, while their outer surfaces are rough and shaggy, like the outer surface of aborted ova, for this surface has been de- tached or torn off from the uterus. Fig. 443. represents a portion of such a membrane, as seen from its inner or cribriform surface. The microscopic characters of these membranes are precisely those of ordinary decidua. b. Hypertrophy of the follicular structures of the uterine mucous membrane. Follicular polypi. Mucous polypi. Cysts. — The patho- logical formations which take their origin in the mucous membrane lining the uterus, con- sist chiefly in hypertrophic growths of that membrane, and of its follicular structures. They present usually two varieties, according as the follicular or the ordinary mucous tissue abounds in their composition. Many of these growths acquire a peduncle, and then consti- tute the mucous or follicular polypi. The follicular structure is most apparent in those growths which spring from the body, and especially from the fundus uteri near the orifices of the Fallopian tubes. These vary in size from a pea to a small plum. They have usually a rounded or oval form, and become partially flattened by the external pressure of the uterine walls. A short and narrow pe- duncle connects them with the spot from which they arise. Externally they are smooth and covered by a layer of epithelium, beneath which is a thin extension of the uterine mu- cous membrane. This is often sufficiently transparent to render visible numerous opa- line spots, indicating the seat of groups of uterine follicles distended and elongated, and containing a semitransparent gelatinous fluid. Between these elongated follicles there is a loose fibrous tissue connecting them together, and giving substance to the mass. These tumours possess little resistance, and are usu- ally soft and elastic. The more solid mucous tumours very ge- nerally acquire a stem, and early take the form of polypi. These mostly arise from be- tween the folds of the lining membrane of the cervix, and are evidently mere hypertrophies UTERUS — (ABNORMAL ANATOMY). of that structure, including a variable propor- tion of the sublying cervical fibrous tissue. In size they range from a pea to a walnut, and occasionally their peduncle measures se- veral inches in length, so that they may pro- Fig. 478. Ptdunculated polypus of the cervix uteri. (After Boivin and Duges.) trude to a considerable distance beyond the vulva. Their form is generally that of an elongated pear. The surface is smooth, though not uniform, being usually nodulated or lobed, and in parts roughened by minute papillary growths. Sometimes one or two of the cer- vical folds or rugae, scarcely altered in cha- racter from their ordinary condition in the healthy cervix, are distinctly visible upon them. These more solid tumours are covered by cylinder or pavement epithelium and hy- pertrophied mucous membrane. Internally they are composed of loose inelastic fibrous tissue, containing a few enlarged and ob- structed follicles, one or two of which may grow more than the rest, and form a cavity distended by a slimy fluid. The growth of both these forms appears to be limited, and they never attain to the size which the fibrous polypi often reach. With the hypertrophies of the follicular structures are also to be classed those single cysts, of the size of a pea, or larger, and sometimes pedunculated, which are very commonly found lying between the cervical folds, or protrud- ing from the os uteri. These consist almost exclusively of distended Nabothian follicles. c. Hypertrophy of the filiform papilla of the cervix. — A variety in the condition of 693 the filiform papillrc upon the vaginal portion of the cervix has been described at p. 639. These papillae, :nstead of being short, and covered by pavement epithelium up to the very margin of the os uteri, as they are upon the rest of the cervical lips, may present the same condition which they have within the cervix, where they are longer and larger, and are not bound down by a continuous layer of covering epithelium. These papilla? often appear at the margin of the os, and form there little tufts, or extend over the lips of the cervix in the crescentic manner already described at p. 639. They then constitute one of those conditions to which, in the pre- sent day, the term ulceration is very fre- quently applied ; yet there*is no more reason for asserting that these are pathological for- mations or conditions, than there is for as- serting the same of the villi within the canal, for both are identical in form. They can only be regarded as pathological structures when they obviously exceed the natural conditions already described. Then, indeed, they may be classed among the hypertrophies of special structures of the cervix, and they will bear the same relation to the natural papillae, that the hypertrophied follicular structures, form- ing the cysts and polypi recently described, bear to the cervical follicles in a healthy con- dition. Both the hypertrophied and the na- tural papillae give to the finger that peculiar velvety or mossy sensation which is usually classed among the diagnostic signs of ulcera- tion of the os uteri. d. Simple inflammatory hypertrophy, with extroversion of the cervical mucous membrane. — The mucous membrane lining the canal of the cervix uteri under chronic inflammation becomes frequently partly everted, so that a portion of the inner surface of one or both walls of the neck is rendered visible at the lower orifice, taking here the place ordinarily occupied by the inner border of the lips of the os tincae. This affection is usually com- bined with a corresponding hypertrophy of the proper tissue of the cervix, and may be compared in its effects to that thickening of the upper lip common in strumous children, which causes the part to become everted. Figures 7. and 8. Plate IX. in Boivin and Duges' Atlas represent an extreme degree of this affection, in which the cervical mucous membrane protrudes to an unusual extent, so that the palmae plicatae and middle raphe' on both sides are seen. In the more common minor degree of hypertrophy with eversion, a crescentic protrusion only of the cervical mu- cous lining occurs. The unevenness of the surface, caused by the slightly swollen and prominent rugae, and as often by the numerous little depressions consisting of enlarged mu- cous crypts, according as one or the other of these is the predominant normal structure in the cervix *, gives to the part during life the appearance of a raw or granular surface, while For a description of these varieties, see p 640. Y Y 3 694 UTERUS AND ITS APPENDAGES. the natural boundary between the lower edges of the cervical canal and the lips of the os tineas being now transferred on to the latter in consequence of this eversion, an abrupt semicircular line becomes visible, which, while it only indicates the natural termination here of the vaginal epithelium (see p. 640.), is fre- quently mistaken for the margin of an ulcer. This condition may be observed upon only one lip, or upon both simultaneously. It re- quires special notice here, not so much for its pathological importance, which appears to me to have been overrated, as on account of cer- tain views of late connected with it, under the belief that it constitutes another form of ulcer of the os or cervix uteri. e. Catarrhal inflammation of the mucous coat. Endo-metritis. Metritis caiarrhalis. Me- trorrhcea. Catarrhus uteri. Acute and chronic catarrh. Leucorrhea. Fluor albus. The ordinary inflammatory affections of the uterine mucous membrane in the unimpreg- nated state, which were formerly known only by the discharges to which they give rise, and which were consequently confounded with similar affections of the vagina, have in recent times been more accurately examined, and traced to their real seat. That the lining membrane of the uterus, and its cervix in a state of acute or chronic inflammation, is the principal source of many of these discharges, is now well ascertained, and the similarity of these affections to the catarrhs of other mu- cous surfaces is now also generally admitted. Hence the term uterine catarrh, under the various forms above quoted, has been employed in most recent works on uterine pathology to designate these affections. Inflammation, whether acute or chronic, may involve the entire uterine mucous membrane, or it may be limited to that of the body or cervix.* The ordinary anatomical conditions of this membrane under inflammation are, first, deep hyperaemic congestion, so that the surface presents a uniform florid red colour, or it is mottled with patches of red, intermixed with paler and less vascular parts. In congestion of the mucous membrane lining the body of the uterus, the superficial capillaries, whose healthy forms are represented injigs. 439 a and b, become intensely loaded, so that rupture occasionally takes place, followed by effusions into the substance of the membrane. A se- rous or sero-sanguinolent, and in more ad- vanced stages, a muco-purulent fluid, covers the surface, while the entire mucous mem- brane becomes swollen, softened, and infil- trated with serum. An abrupt line of demar- cation, when the congestion is limited to the uterine body, marks the boundary between that cavity and the cervix, the lining mem- brane of which may retain its natural pale colour, — just such an abrupt line of demarca- tion between the highly congested membrane * This distinction, not usually observed by con- tinental authors, has been emphatically made by Dr. H. Bennet. A Practical Treatise on Inflamma- tion of the Uterus. 3d edit. 1853. of the uterine body and the paler lining of the cervix, as occurs during menstruation or in early pregnancy.* When inflammation affects chiefly or ex- clusively the cervical mucous membrane, this becomes turgid and swollen, and its vessels congested. The congestion affects more par- ticularly the capillaries of the vaginal portion of the cervix, and of the interior of the canal near the orifice. The lips of the os tineas are at the same time tumid, the os is enlarged, and the cervical canal expanded ; changes which indicate that the structures immediately beneath the mucous membrane are then also involved. A loss of epithelium in the neigh- bourhood of the external orifice, more or less extensive, may occasionally accompany the severer forms of this affection. From this it results that the turgid and vascular papillae beneath becomes exposed, and when these are also hypertrophied, the surface acquires the condition commonly termed granular. The natural or healthy secretions of the cervix become materially altered under ca- tarrh. In a normal state the cervical secretion is sufficient in quantity to cover the mucous folds, and to fill the crypts and furrows, and occasionally to block up the entire canal. It consists of a viscid, tenacious, and nearly transparent fluid, enveloping numerous mu- cous corpuscles, granules, and epithelial scales. When the catarrhal state ensues, this fluid is greatly increased in quantity, and, according to the severity of the affection, it passes through the various conditions of a viscid transparent jelly, resembling clear starch or white of egg, of a thicker cream-like fluid, or of a puriform mucus, in colour nearly resem- bling pus. Blood also is occasionally found mixed with these secretions.f The ordinary secretions of the cervix, as shown by Dr. Whitehead, have an alkaline reaction within that canal, but they speedily become acid when mixed with the vaginal secretions, which also cause the previously transparent cervical products to become opaque as they pass through the vagina. Acute specific catarrh of the vagina (gon- orrhoea), as well as simple catarrh of that canal, may be associated with the foregoing affections. Ulceration of the mucous coat. Melro-hel- cosis. Granular ulcer. Simple erosion, abra- sion and excoriation. — These terms have been severally employed to designate certain con- ditions of the os and cervix uteri, regarding the nature, frequency and pathological import- ance of which, as is very well known, great diversities of opinion are in the present day entertained. The affections of the cervix uteri, which * This point, under both these conditions, is illustrated with great fidelity in the coloured de- lineations of Boivin and Duges. See Atlas, PI. I. fig. 4., and PI. II. fig. 6. t A descriptive account of some of these fluids, accompanied by illustrations, will be found in the paper of Dr. Tyler Smith, in Vol. XXXV. of the Med. Chir. Trans. UTERUS — (ABNORMAL ANATOMY). are commonly deemed ulcerative, are admitted by those who so describe them to possess certain characteristic and exceptional features by which they are distinguished from ulcers of other parts. For it is truly asserted, that " whatever the character of an inflam- matory ulceration of the cervix the ulcerated surface is never excavated ; it is always on a level with, or above the non-ulcerated tissues that limit it, and its margin never presents an abrupt induration."* Further, with regard to the position of these "sores,"' two principal circumstances have been almost invariably noticed. As seen by the aid of the speculum, they either present the appearance of a red and apparently raw surface commencing, within the cervix, or at the margin of the os tincae, and spread- ing outwardly to a limited extent over one or both lips ; or they form numerous isolated red spots, or sometimes depressions dotted at nearly regular intervals over the whole surface of the vaginal portion of the cervix, and varying in size from a pin's head to a millet seed. It will aid description to take advantage of these peculiarities for the purpose of arrang- ing in two groups or classes the various pa- thological and other states of the uterine cervix, which severally exhibit the characters just mentioned. Many of these, however, when minutely examined, and tested by the aid of the microscope, so little fulfil the con- ditions of true ulceration, as to make it appear that such a term could only have been applied to them under, in some instances perhaps a misapprehended, and in others a strained, view of their real nature. In the first class ma}7 be included those cases in which the filiform papillae of the cervix are in an uncovered state, and either of their natural size or hypertrophied ; ever- sions of the cervical mucous membrane j and hyper-trophic growths of the same. All, or nearly all the non-excavated ulcers, so termed, are referable to one or other of these con- ditions. Beginning with the normal variety of struc- ture already described, in which the central columnar folds of the cervical mucous mem- brane take a perpendicular direction (fig. 424.), and after running down to the very margin of the os tinea? terminate there in a narrow bor- der, or tuft of filiform papillae, the simplest form which has been viewed as abrasion, excoriation, or ulcer, is thus produced. The velvety pile, constituting one of the most common features of pseudo-ulcer, being formed by these slightly prominent papillae, fringing the margins of the os. In a more marked degree of the same con- dition, instead of a narrow line or margin, a broader crescentic patch of uncovered filiform papillae extends outwardly over either or both lips. The papillae are gathered into little groups, whose appearance, when magnified by a common hand lens, may be compared to * J. H. Bennet, foe. cit. p. 79. 695 miniature wheat -sheaves heaped together. Each papilla is perfectly free and possesses its own proper epithelial coat.* This little group, which may cover half the circum- ference of the cervical lip, is encircled or semi-encircled by a thin non-elevated margin, where the ordinary pavement epithelium co- vering the rest of the cervical lip terminates. There is no appearance of any loss of tissue here, beyond that occasioned by the absence of a portion of that dense layer of epithelium, which, like a sheet cast over the papillae, usually invests them, as far as the inner bor- ders of the cervical lips, with one common covering, in addition to their own proper coat. These papillae may retain their normal size, or they may be hypertrophied. On account of the large number of capillaries which they contain, and from the circumstance that they are uninvested by vaginal epithelium, they present a florid and often turgid aspect. When such a part is brushed over with nitrate of silver, a line of demarcation is in- stantly produced, the mucus entangled among the naked villi is coagulated, and a cloud of white chloride of silver is precipi- tated among them, while the parts adjacent which are covered by pavement epithelium are less affected, and exhibit only a pinkish white opalescence, that contrasts with the dead white within, and with the abruptly marked border of the epithelial edge. In this way is produced another effect commonly quoted as a test of ulceration. f Those bolder and more marked projections of a florid red colour which begin also from the inner margins of the os, and spread out- wardly, looking like granulations, consist of hypertrophies of pre-existing structures inter- mixed occasionally, though more rarely, I be- lieve, with pathological new formations. Such hypertrophies are chiefly the follow- ing, viz. eversion of the cervical lining as described at p. 693. ; hypertrophies of the crested folds of that membrane, which when everted, enlarged, and inflamed, constitute the condition termed " cockscomb granulation ; " and lastly, distended and closed muciparous follicles gathered in groups around the os and intermixed with the hypertrophied structures just noticed. These latter add to the irre- gularities and nodosities of the surface, and together with fissures formed by deepened natural folds, and varicose distensions of ves- sels, constitute the more irregular forms of hypertrophies which have been termed ulcers. The second class of pseudo-ulcers termed commonly aphthae and granulations, viz. those which are dotted at regular intervals over the lips of the cervix, but are often more endur- ing than herpes, and do not usually in their progress coalesce as herpetic spots when con- tiguous almost invariably do ; these consist of * Regarding the nature of this coat see p. 639. t Precisely such an effect may be produced upon mucus scraped with a piece of glass from the tongue, and touched with argenti nitras. Y Y 4 696 UTERUS AND ITS APPENDAGES. enlarged muciparous follicles*, which in three different conditions or stages correspond with three varieties of pseudo- ulcers of the aph- thous kind. In the first variety the follicles are closed and project like millet seeds above the general level of the cervix. They contain a little glairy fluid, and may be compared to the distended closed follicles described at p. 640., as occurring within the cervical and uterine cavities. They are almost always placed at such regular intervals apart, that they must be regarded as natural structures enlarged, rather than as pathological new for- mations. The second variety consists not of closed but open follicles similarly arranged. Within and at the bottom of many of these may be seen the filiform papillae enclosed, cup-like, and resembling the stamens in a half opened flower. Similar follicles to these occur some- times within the cervix under ordinary circum- stances. When these papillae become hypertrophied and sprout out above the cup-like level of the containing follicles they form florid-looking and elevated spots resembling granulations in appearance, and these constitute a third va- riety — the " granulations simples sans ulce- rations" of Pichard.-f- The foregoing examples have been here passed in review for the purpose of illustrat- ing the principal anatomical and pathological conditions of the uterine cervix, which when viewed by the speculum during life exhibit appearances that are regarded by many ob- servers in the present day as affording un- mistakeable characteristics of ulceration. With this object they have been here grouped to- gether, but they do not form a class ; many of them indeed have no pathological relation- ship, and to few can the term ulceration be regarded as appropriate. In order, therefore, to eliminate from the category those condi- tions which have no title to be considered as ulcers, it is needful to apply to them the test of a definition. With this view, and also for the purpose of avoiding the confusion which from the time of Hunter downwards has at- tended the employment of various terms for the designation of ulcerative processes, of those at least by which the particles of open or exposed surfaces are removed, it may be well to adopt some such distinction as that proposed by Mr. Paget, namely, to regard as abrasions or excoriations those conditions in which the epithelium or epidermis of an in- flamed part is alone removed, and those only as liberations in which the removal extends further to the vascular or proper tissues be- neath the epidermis.}: Judged by this test, there may be excluded, first, all those apparent sores which, begin- * See p. G40. t Excellent representations of the varieties de- scribed above will be found in Boivin and Duges' Atlas, pi. 25. 27. and 33., and in Pichard, Mai. des Femmes, pi. 3. J Surgical Pathology, vol. i. p. 419. ning invariably from within the margins of the os, and appearing to spread outwardly more or less over the cervical lips, present a florid and often granular aspect, and being on a level with surrounding parts, and without de- finite edges or raised border, fulfil all the con- ditions commonly assigned to ulcers of the uterine neck. These, almost without excep- tion, consist of the inflammatory conditions already described as hypertrophies and ever- sions of the cervical mucous membrane. The apparently raw surface exposed to the eye is not usually any portion of the outer cervix, but the swollen inner surface of the walls of the cervical canal now everted and brought into view, just as the interior of the lip is brought into view in common strumous thickening about the mouth. The margin of this apparent ulcer is the normal boundary of the os, or line of demarcation between the vaginal and cervical mucous membrane, now disturbed and thrown out of its natural place. The granulations upon this surface are the thickened and inflamed papillae, follicles, and rugae of the cervical canal. The edges are not raised because they simply form the boundary between the vaginal and cervical epithelium, and the centre is not depressed, because there is no erosion nor any loss of tissue. These conditions of the uterine cervix in respect of their true pathological relations are exactly allied, in their different degrees, to the inflammatory conditions of the eyelid termed respectively Lippitudo, Ectropion and granular lid. Both are attended by like hypertrophies of structure and corresponding depravements of their healthy secretions. Both are reduced to their normal condition by similar or even identical methods of treat- ment, and both are alike entirely removed from the category of ulcers. Next to these may be enumerated the con- ditions of the uterine neck which are distin- guished by loss instead of hypertrophy of tissue. When this loss consists solely in de- tachment of epithelium the term " epithelial exfoliation" appears to be a more appropri- ate designation and preferable in many re- spects to " excoriation or abrasion," — terms which seem to imply something of violence in the mode of production of these conditions. Exfoliation of the tesselated epithelium covering the vaginal portion of the cervix ap- pears to take place under some circumstances with great ease. In uterine catarrh for ex- ample, this shedding of epithelium com- mences at the borders of the os, and extends outwardly. Or it may involve the entire epithelium of the vaginal portion of the cervix together even with that of the vagina itself, these being sometimes thrown off like a cast. In such cases, a fresh epithelium is formed beneath the old one that has been detached.* But if the epithelium is not renewed the villi remain denuded. This condition may be precisely imitated after death by macerating the part for a few days, and then peeling off * See also page 707. and note. UTERUS — (ABNORMAL ANATOMY). the epithelial covering. And it is probable that profuse discharges lying in constant con- tact with these parts during life may similarly assist in softening and detaching this struc- ture. But it is deserving of consideration that the papilla; of the outer surface of the os by this uncovering are merely reduced to the same anatomical condition as those of like form within the cervical canal. Whether this deprivation of a natural covering usually found here renders the villi of the outer cervix, which are probably .specially sentient structures, more susceptible ot irritation, particularly when in a hypertrophied state, is a matter for consider- ation that would extend the present inquiry beyond its proper limits here. But it is pro- bable that in this way may be explained those constitutional and local erethisms which often accompany faulty states of the uterine cervix ; and which have led to such conditions being invested with a degree of importance often in excess of their true pathological value. But the villi may be found in some speci- mens denuded of vaginal epithelium, yet with- out any evidence of inflammatory or other changes. Such a part may appear quite na- tural. The villi upon the cervical lips, and those within the canal being in every respect identical and alike natural in appearance, so that the strictest microscopical investigation may fail to detect any difference between them. The examination of such specimens has satis- fied me that the vaginal epithelium does not always normally terminate precisely at the inner borders of the uterine lips, but may cease at some point short of this.* In the third place are to be noticed those cases in which the process of removal extends to tissues deeper than the epithelium, i. e. to the villi, the vascular and fibrous, and other tissues. The removal of such tissues here necessarily produces excavation with definite borders, and all the characters of a true ulce- ration. Ulcers of the uterine cervix exhibiting these features are almost exclusively either syphilitic, phagedenic, cancerous, or cancroid, and such as occur upon the surface of a pro- lapsed uterus. They are seldom, I believe, scrofulous, and more rarely if ever do ulcers occur upon the uterine neck as the result of simple inflammation, fulfilling the conditions that would entitle them to be admitted into the category of true ulcerations. Distensions of the uterine cavity, by liquid or gaseous contents, constitute the affections termed respectively hydrometra, hamiatometra, and physometra. These collections result usually from narrowing or atresia of some portion of the vagina or cervix, whereby the natural or morbid secretions of the uterus become pent up in its cavity. They are generally accompanied by hypertrophy, but sometimes by atrophy of the uterine walls. * Some of these morphological varieties have been described in a preceding page; and such, to- gether with many of the hypertrophies already noticed, have been repeatedly submitted to me during life as examples of ulcers of the uterine neck. 697 Hydrometra results usually from a combina- tion of chronic uterine catarrh with oblitera- tion, absolute or relative, of the lower uterine orifices. Such obliteration, for example, may be caused by chronic disease of the cervix, by the presence of a submucous fibroid or a cer- vical polypus obstructing the cervical canal, or by the pressure of an enlarged neighbour- ing viscus, as the ovary *, or of a chronic ab- scess. If, with these or similar conditions, uterine catarrh co-exists, the secretion from the mucous membrane collects in, and gradu- ally distends, the cavity ; the walls of the uterus becoming at the same time hypertro- phied, or sometimes atrophied.f The fluid which accumulates in such cases may be thin and watery, but it is more often puriform, and in some instances, as in Dr. Hooper's ex- ample, which resulted from the opening of an abscess into the uterine cavity, it consists of pure pus. To these cases, the term pyo-mctra would be perhaps more appropriate. Collec- tions of these kinds amount usually to several ounces, or may reach one or two pounds. The uterus enlarges to the size of a fist, and, in rare examples, to the bulk of the gravid uterus at term.J Pure hydrometra, i. e. without haematometra, can only occur after the cli- macteric period, or in combination with ame- norrhoea. When the inner and outer os uteri are both closed, and the cervical and uterine cavities are at the same time distended, the organ re- sembles an hourglass in form. This consti- tutes the uterus bicameratus vetularum of Mayer. Hydrometra is to be distinguished from hydrorrhoea uteri, in which there is no ob- struction, but a continual escape of a thin, watery fluid, often to a large amount. This condition, which may occur both in the unim- pregnated and gravid uterus, is apparently dependent upon excessive activity of the fol- licular structure of the cervix, and may be viewed as a coryza of that part. Hcematometra consists in a collection of blood, usually menstrual, in the uterine ca- vity. It is commonly associated with atresia of the vagina at some point, generally at the orifice, as when the hymen is imperforate, or when the orifice has become closed by inflam- mation of the vulva in early infancy. Under these circumstances, when the menstrual age arrives, the fluid, for which there is no outlet, collects in, and distends, the cavity of the uterus, whose walls at the same time become hypertrophied, as in pregnancy ; or occasion- ally attenuated, as in the case of hydrometra just stated. The fluid, which is generally dark-coloured, and of the consistence of trea. cle, may, if not artificially evacuated, escape spontaneously in various ways, viz. into the abdominal cavity, by travelling along the ovi- ducts, or through lacerated or ulcerated open- * Scanzoni, loc. cit. p. 165. f Hooper, Morbid Anat. of Uterus, pi. III. j Case. Dr. A. T. Thomson, Med. Chir. Trans, vol. xiii. 698 UTERUS AND ITS APPENDAGES. ings in the uterine walls ; or, if previous ad- hesions are formed, the fluid may escape by the vagina or rectum. Haematometra may occur also in certain malformations of the uterus, as already described (p. 680.). P/iysometra. Pneumatosis s. tympanites uteri. —This affection, known to Hippocrates* and Aretaeusf, consists in a collection of air in the cavity of the uterus, which makes its escape from time to time by the vagina, with or without explosion. The air may be dry, or accompanied by more or less fluid (physometra humida). In ordinary cases it is inodorous, but occasionally it possesses a most offensive odour. In these latter cases (physometra putrida), the gas appears to be generated by decomposition of some substance within the uterus, as a putrid foetus, the remains of a pla- centa left in utero, and the like, while the generation of an inodorous gas, on the other hand, without the presence of any such sub- stances, within the uterus, can only be com- pared with those sudden developments of air in the stomach and intestines which often take place in hysterical women. Hydatids. — A case of acephalocysts within the ovary has been given at p. 584., but this is so rare an affection of the uterus that no anatomical collection, 1 believe, in this city contains an example of it. Rokitansky's often-quoted casef appears to be the only certain instance of acephalocysts in the ute- rine cavity which pathologists in the present day are able to adduce. In the " Lancet" of 1840, vol. i. p. 691., a case is reported as one of uterine hydatids, the nature of which is not very clear. That they were not acephalocysts (echinococcus vesicles) may be inferred from the description. This case, which is quoted here as an example of the more doubtful instances of hydatids, was probably one of interstitial pregnancy (see p. 621.) combined with the vesicular degene- ration of the chorion described in the next paragraph. Those vesicular masses and groups or strings of watery vesicles, falsely termed hydatids, which are so frequently expelled from the uterus accompanied or preceded by abundant serous discharges, combined with rapid dis- tension of the abdomen and some symptoms of pregnancy, consist invariably of moniliform enlargements of the villi of an imperfectly de- veloped chorion or placenta. It is almost needless to observe that the presence of a true chorion structure, which these substances invariably exhibit, even in their most degenerated and abnormal forms $, constitutes unquestionable evidence of a prior act of impregnation. Connected with these, when the degeneration is not much advanced, may be sometimes found an embryo per- * De Morbis Mulierum. t De Causis et Signis Morb. Diuturn. j Loc. cit. vol. ii. p. 291. § For descriptions and illustrations of these struc- tures see Wedl, Pathological Histology (Syd. Soc.), P. A/—. fectly or incompletely developed*, but in higher grades of this abnormal state the em- bryo invariably perishes or is unformed. Narrowing and obliteration of the uterine ca- vity. Atresia. — The defects which come under this head may be either congenital or ac- quired. They may consist in a simple nar- rowing, or stricture of the cavities of the uterus, or of the apertures leading to them, or in a complete obliteration of some or all of these. Probably most of the cases of atresia which do not originate in the malformations already described, have resulted from the or- ganisation of the products of inflammation affecting these parts. Obliteration of the external os uteri, either partial or complete, is the most common of these conditions. In minor degrees, where the form of the parts is not lost in adhesions with adjacent structures, the os is found closed by narrow membranous threads or bands. If the closure is not complete, pregnancy may ensue, but labour is obstructed, and the original seat of the os is then with difficulty traced, or it cannot be found. The cervical canal may be e.ntirely oblite- rated by the formation of fibrous tissue, in which smooth muscular fibres have been some- times found. Obliteration, or narrowing of the inner ute- rine orifice, may occur in the progress of senile atrophy, or as a result of the same processes that cause obliterations lower down. All the foregoing atresia? may result in the collections of fluids within the uterine cavity recently de- scribed. Lastly, the cavity of the uterine body may be so completely closed that no trace of it can be found. Such an example is delineated in PI. 13. of Boivin's and Duges' Atlas, which contains also the figure of another uterus, the original seat of whose cavity is indicated only by a narrow triangular band of white tissue nearly as hard as cartilage. Pathologic conditions which may involve se- veral of the uterine tissues. Cancer. — The two main disorganising pro- cesses by which the structure of the uterus is metamorphosed or disintegrated and ultimately more or less destroyed, are those under which cancer and fibroid are respectively developed in its tissues. Of these, regarded as destruc- tive agents, cancer ranks second in point of frequency, but first in potency. Cancer occurs in the uterus as in the ovaries, under the three principal varieties of encepha- loid, scirrhous, and colloid. But while in the latter organ colloid as a primary disease is certainly more common than either of the other two ; in the uterus, on the other hand, both scirrhous and colloid are rare, while ence- phaloid constitutes the chief form under which cancer is found. The development of cancer may undoubt- edly commence in any portion of the uterus, but the number of instances in which it occurs, * Granville, Graphic Illustrations of Abortion pi. iv. and v. UTERUS — (ABNORMAL ANATOMY). first, in the cervix, and especially in the va- ginal portion, is so preponderating, that this may be regarded as mainly the seat of origin of uterine cancer. The comparative rarity of opportunities for examining uterine cancer in the incipient stage, has limited to a certain extent our knowledge of this part of the subject. The cervix in the incipient stage, smooth, tense and hard, or exhibiting upon its surface here and there knotty projections, is found upon section to have its tissues infiltrated in parts by the cancerous structure, which differs in the character and relative proportions of its elements, according to the form which the cancer assumes. In the medullary variety a white cream-like or lardaceous semi-fluid mat- ter, composed of the usual cancer constituents, is found interspersed among the meshes of a loose reticulum, in the softer portions of which few if any of the normal uterine fibres can be traced. The larger preponderance of the en- cephaloid matter, compared with the fibrous stroma, occasions that semi-elastic feel which the part early acquires, and at the same time constitutes the main difference between en- cephaloid and scirrhous cancer. In the scirrhous or fibrous variety the greater hardness of the structures is depend- ent upon the presence of a large proportion of a coarser fibrous stroma, composed of dense white fibres, the minute interspaces of which are occupied by a greyish or reddish softer and often pulpy substance, which may be obtained by scraping, or may be squeezed from the part. In the harder forms of scirrhous but little fluid is so obtainable ; but in some specimens here and there, softer portions are found from which a fluid cream-like matter exudes, dif- fering in no respect from the pulp of ence- phaloid cancer. These and the softer portions obtained by scraping are composed of cancer cells with molecules, granules, and disinte- grated fibrous tissue. The irregular nodulated projections oc- casioned by the unequal development of the cancer structure rapidly increase in the en- cephaloid variety, and the cervix becomes much enlarged. The surface of the more projecting portions becomes florid and vas- cular, and these portions pass first into ul- ceration by thinning and absorption of their mucous covering. The creamy or cheese- like contents of these tuberculated portions then escape, and being sometimes of a yel- low colour may be mistaken for tuberculous matter. This stage is followed by the formation of one or more corresponding ulcers upon the outer cervix, which coalescing destroy the remaining portions of the mucous membrane, and spreading up the cervical canal, convert it into an irregular funnel-shaped cavity, bounded below by hard rugged margins. Or fungous vascular growths, friable and easily bleeding, sprout from the part and entirely destroy its natural configuration. A yellow or greenish-brown sanious discharge, of a highly fetid odour, mixed occasionally with 699 florid blood and ultimately with fragments of putrid tissue, dates from the commencement of ulceration, and increases in proportion to the extent of surface denuded. The frag- ments of putrefied tissue which hang from the ulcerated surfaces, and occasionally pass away in the discharges, consist mainly of connec- tive tissue fibres, which are more slowly dis- integrated, stained of a dirty brown colour by infiltration with decomposed blood. By these disintegrating processes both lips, and finally the cervix itself, are destroyed and removed ; the cancer structures being con- tinually deposited in advance of the ulcera- tion, while the fund us and even the body of the uterus may still remain sound. In like manner cancerous deposits take place in the fibrous tissue surrounding the uterine neck, and attaching it to adjacent parts. Thus the uterus becomes fixed in the pelvis, and at the same time a way is paved for the further ex- tension of destructive ulceration, by which first the bladder and then the rectum are penetrated, and the disease further extending down the vagina, the whole is laid open into one ulcerous cloaca {fig* 479.). If life is Cancer of the neck of the uterus («), extending to the bladder (6), rectum (r), and upper part of the vagina (»). (Ad Nat.) maintained beyond this point the pelvis be- comes lined with cancerous matter, and, the peritoneum inflaming, all the adjacent parts become agglutinated together, until finally the ulceration may extend into and la} open the peritoneal cavity itself. The penetration of the bladder earlier than the rectum, which almost uniformly obtains, is explained by the different modes of connexion of the cervix with these two parts. Since nothing but fibrous tissue intervenes between the bladder and the anterior cervical wall (fig. 426. b b and 433 F), the cancer elements are readily deposited, and extended in this direction, while the posterior wall being se- parated from the rectum by a double fold of 700 UTERUS AND ITS APPENDAGES. peritoneum (fig. 426. 433. G). the cancer mat- breaks through the surface ; while in the ter does not so easily penetrate through this, course of time ulcerations form upon the not at least until adhesions have formed.* most prominent portions, and these coalescing, But cancer may commence in the fundus while increased deposits of cancroid take or body, instead of in the cervix, although place in the sublying tissues, which in turn this is rare ; or it may extend to the uterus are also destroyed, a sore, more or less ex- from the ovary. In this way extensive dis- tensive, is formed that in its further aspect organisation of the adjacent parts may occur, and progress very nearly resembles encepha- the cervix remaining intact, f loid cancer. Cancer, when thus developed, especially in Regarding the structure of these cancroid the encephaloid variety, assumes often the formations, they are, according to Virchow, form of distinct masses or tumours, rather at the commencement simple papillary growths, than of an infiltration of the tissues. and later assume the characters of cancroid. These tumours may be imbedded in the At first they appear in the form of small vil- uterine walls, or form numerous irregular lous projections from the surface, composed rounded and sometimes pedunculated masses, of an outer very thick layer of peripheral variously attached to, or projecting from their epithelial plates, and an inner one of cylinder surface. On the other hand such a distinct ephithelium, the interior of the villus consist- mass formed in the substance of the uterine ing of large blood-vessels. These vessels are walls, or beneath the mucous membrane, may chiefly colossal thin-walled capillaries, which in the course of growth push the latter before either form simple loops at the extremities of it, and, subsequently acquiring a stem, may the villi between the layers of epithelium, or fill the uterine cavity or protrude into the ramify in compound loops over the surface, vagina, and constitute a malignant polypus. or lastly, present a retiform arrangement. In most cases of uterine cancer the uterus The great size, tenuity, and superficial posi- is the primary, and except in those instances tion of these vessels explains the profuse dis- where the disease has spread by direct ex- charge of watery fluid, and frequent bleedings, tension to adjacent parts, it may remain which constitute such striking features in the throughout the sole organ attacked. Or progress of the cauliflower excrescence, as uterine cancer may be associated with like well as the entire collapse and almost total formations in the stomach, mamma, ovary, disappearance of those tumours after death, &c., and be developed concurrently with or so that only slight traces of them are found on post-mortem examination. At the commencement the papillae are single and close-set, so that the surface, as mited in its commencement to the vaginal Clarke describes it, is merely granular. The portion of the cervix, and presents the follow- peculiar cauliflower form is occasioned by the ing principal varieties. It may appear under branching of the papillae, which ultimately the form, of papillary growths, resembling con- form fringes an inch in length. After this dylomata, which spring from the mucous sur- superficial process of growth has continued face, and form little compact masses that for a certain time, cancroid alveolar spaces gradually, by the growth and elongation of the begin to be formed at the base, between the papillae, become soft, pulpy, and brittle, and fibrous and muscular layers of the organ. At easily bleed on being touched. After a time first these appear as simple spaces, with a basis of cancroid is developed in the cervical epithelial contents, but later are found alveoli, tissues, or the papillary growth appears upon from whose parietes new papillae spring, a larger scale, forming a hard, knotty, and which also become ramified, constituting brittle mass, which grows with tolerable ra- arborescent proliferous growths, pidity, and ultimately more or less fills the Corroding ulcer. — Here may be noticed an vagina or protrudes from the vulva. In form affection of the uterine cervix, whose exact the growth often resembles a cauliflower, to pathological relations have not been deter - which it was likened by Dr. John Clarke. The mined with sufficient accuracy. The corrod- surface is of a bright flesh colour, and is ing ulcer, first described by Dr. John Clarke, covered with small projections or granules, and compared by Rokitansky to a phagede- These again are united into larger masses or nic (cancerous) sore of the skin, differs lobes, set upon short and broad stems, that mainly from cancer in the absence of a cancer ultimately coalesce into a common basis basis, or of cancerous infiltration of adjacent formed by one or both lips of the cervix, tissues, while it resembles the destructive The whole tumour has a certain firmness and march of cancer in its mode of gradually dis- soiidity ; but the superficial granules are so integrating, and destroying the os and cervix, brittle that slight handling causes some to and even portions of the body of the uterus, break away, a free haemorrhage resulting. Or and extending to the bladder, rectum, and ad- the cancroid, after being developed in and jacent structures. The characters of this beneath the mucous membrane of the cervix ulcer are those of a ragged, irregular-margined in the form of little granular masses, gradually sore, with a brownish or greyish base, from which issues a thick purulent or copious * Dr. West is, I believe, the only author who has ^atery secretion. The margins and base may hitherto pointed out the true cause of this difference, be thickened by inflammation, but there are f See case, p. 593. no granulations. consecutively to these. Cancroid. Epithelial cancer. Cauliflower excrescence. — Cancroid of the uterus is li- UTERUS — (ABNORMAL ANATOMY). 701 Upon the question of the nature of this form of ulceration Foerster gives a useful hint. After describing a case which fell un- der his notice, and where he could find no traces of either encephaloid or epithelial can- cer in the base of the ulcer, he mentions another which also to the naked eye ap- peared to have no cancerous basis, and yet on microscopic examination the entire ba.se of the ulcer, to the depth of a line, was found to consist of cancer structure.* May not the thinness of this layer, by limiting the pabulum \\hich feeds the progress of the ulcer, explain the slow advances of the latter observable in some cases of corroding ulcer ? Tubercle rarely effects the uterus, and still more rarely is it a primary disease of that organ. Tubercle of the uterus exhibits the follow- ing peculiarities. The tuberculous deposit is limited in the first instance to the mucous membrane of the body of the organ. Here it occurs either in the form of tuberculous granulations, isolated or collected in groups, or more often as a uniform infiltration, limited at first to the mucous membrane, but ulti- mately penetrating more or less deeply the sublying uterine parenchyma, and accompa- nied by hypertrophy of the muscular coat. In the subsequent metamorphosis of the tu- bercular formation the infiltered membrane softens and melts down, so that the cavity becomes filled by a purulent pulpy fluid. The tubercular infiltration terminates abruptly at the inner uterine orifice -j- ; or if rarely it penetrates the cervical canal or appears upon the vaginal portion, it is then only in the form of isolated tubercular granulations, which latter may probably pass into tubercular ul- cers. Tuberculosis of the uterus is usually as- sociated with a corresponding condition of the mucous membrane lining the Fallopian tubes. These latter are found distended and their canals filled by caseous tuberculous matter. Solutions of Continuity. Laceration of the walls of the uterus occurs under various circumstances. It happens rarely in the unimpregnated organ, more fre- quently during pregnancy, and most commonly during labour. Rupture of the walls of the unimpregnated uterus can only occur under abnormal condi- tions of the organ, as from considerable growths of fibroid, or from great distension of the cavity by watery, puriform, or sanguineous fluids, such* as occur in hydro- and haema- tometra. See p. 697. Rupture during pregnancy may happen at almost any period, but chiefly during the latter half* although it may take place even as early as the second month, as from vo- miting.}: Or it may be occasioned by violent * Handbuch der speciellen pathologischen Ana- tomic, 1854, p. 318. f Boivin and Duges' Atlas, pi. xvi. J Case by Collineau. Journal Gen. de Med. 1808. spasmodic contraction, or from contusion or sudden concussion. It is most likely to happen in the case of the imperfectly de- veloped uterus, as in the uterus unicornis, of which a description has been already given (p. 679.), or in the case of gestation in the uterine portion of the Fallopian tube (gra- viditas interstitialis, p. 621.). Rupture of the uterus may occur upon only very slight exertion, as in the act of stooping*, or even without any obvious cause, as during sleep.f Most of the recorded cases, however, of spontaneous rupture of the uterus have occurred during labour, under violent uterine action, combined with some unusual resistance to the passage of the child, such as is occasioned by a distorted or fractured pelvis, a tumour, an unyielding state of the os and cervix uteri, or by some malposition or unusual bulk of the child. It may also occur from violence in instrumental delivery, or from injudicious efforts to turn the child. The seat of rupture is most commonly the neighbourhood of the cervix, the laceration extending very often through the os to the vagina, or upwards, so as to involve more or less of the body of the uterus. It occurs oftenest at the sides, less frequently in the anterior or posterior walls, and least of all at the fundus. The course of the laceration is generally oblique, rarely in the* horizontal direction. It may, however, extend round the whole circumference of the cervix, the lower seg- ment of the uterus being forced off in a sin- gle piece, before the presenting part of the child.J The length of the rupture may be such as to admit of the child escaping into the ab- domen, among the intestines, or it may be only very slight. All the coats of the uterus are not necessarily involved. The peritoneum alone may be torn, numerous rents (40—60) occurring in this coat, without extending to the muscular tissue.^ These lacerations occur in most instances where the uterine tissues are perfectly healthy. In some cases the walls of the uterus have been apparently attenuated, the attenuation being attributed to pressure upon the spine or pelvic bones, or there has been more or less evidence of antecedent inflammation near the seat of the accident. Perforation of the uterine walls occurs in cancer, (Jig. 479.) followed by the establish- ment of fistulous communications with the bladder and rectum ; or from penetrating abscess at the surface of the uterus ; or as a consequence of adhesions formed between the uterus and an ovarian cyst, the contents of * Mr. Glen's case in the eighth month of gestation, related by Dr. Merriman. Synopsis of Difficult Parturition, 1826, p. 268. t Mr. Ilott's case, sixth month. Med. Repository, vol. vii. J Mr. Scott's case. Medico- Chirurgical Transac- tions, 1821. § Trans, for the Improvement of Med. and Surg. Knowledge, vol. iii. 702 UTERUS AND ITS APPENDAGES. the latter being discharged through the uterine cavity. Pathological conditions of the Uterus after Parturition. Irregular contraction. — After tedious and exhausting labours, or those in which the uterus has been rapidly emptied, or under other circumstances which tend to the production of a general or partial atony of the organ, its post-partum contractions are often imperfect. The whole uterus may re- main relaxed and undiminished in size, or a portion only of the walls may contract while the rest remain inactive. From the latter combination result the hour-glass and other irregular forms of the organ when the cavity of the uterus is partitioned into two chambers, in the upper of which a part or the whole of the placenta may be imprisoned. The seat of constriction being either near the fundus, or the centre of the uterus, or the neigh- bourhood of the cervix. This condition is often attended by haemorrhage from the un- contracted portions of the uterine walls. In explanation of these irregular contrac- tions, it has been usually assumed that the contracted portions consist of the fibres that have retained their vigour, and the relaxed parts of those that have been exhausted. Numerous observations, however, have satis- fied me that this is but an imperfect and, in some respects, an errdneous interpretation of this phenomenon. It appears to depend rather upon arrested peristaltic action, which may indeed be, and probably is, the result of ex- haustion ; not, however, of a particular set of fibres, but of the ganglionic nerves which especially govern this movement of the organ. So that the peristaltic contraction in travelling along the uterus from os to fundus, is stopped in some part of its course. This explanation is consistent with the fact that these constric- tions are not confined to any special region, but may occur at any point between the cer- vix and the fundus, and particularly with the circumstance that in some cases the con- stricted part may change its seat, the contrac- tion being sometimes felt to travel onwards towards the fundus, while the hand is em- ployed within the uterus in removing the pla- centa. See p. 673. Rokitansky describes a remarkable result of partial contraction, with relaxation of the rest of the uterine fibre. When this occurs at the placental region, the part that gave at- tachment to the placenta being relaxed is forced into the cavity of the uterus by the superior tonicity of the surrounding tissues, and there constitutes a kind of tumour which, on account of its form and the protracted haemorrhage that usually ensues, may be mistaken for a polypus or a haematoid growth. Retarded and incomplete involution consists in an arrest of those metamorphic processes by which the uterus after parturition is re- stored to its ordinary condition. All inflam- matory puerperal processes are attended by this condition in a greater or less degree. But involution may be arrested without in- flammatory action, so that the uterus remains undiminished in bulk, its fibre uncontracted, and its tissues unrenovated for several weeks or months after labour. The soft flabby organ is easily distinguished above the pubes, reach- ing sometimes as high as the umbilicus ; while its cavity, tested by the uterine sound, may measure several inches in depth. Puerperal inflammations. — The puerperal or post-partum inflammatory affections of the uterus may be noticed according as they in- volve the peritoneum, the proper tissue to- gether with the blood-vessels and absorbents, or the lining membrane of the organ. Puerperal endometritis. — Inflammation of the internal surface of the uterus occurs, as a pri- mary affection of that organ, shortly (within a few hours or days) after labour. It takes the form usually of plastic inflammation, whose first seat is either the surface which has been exposed by the separation of the placenta, or certain portions that have suffered injury, such as lacerations and contusions, occurring dur- ing forced or spontaneous delivery. From these points, the inflammatory action may spread over the entire inner superficies of the organ, or it may involve more or less deeply the uterine parenchyma, and ultimately extend by contiguity to the peritoneum itself. The form of inflammation, and the nature of the exudative products, exhibit great variations in different instances, variations which are espe- cially observable in respect of individual and epidemic influences, and are directly connected with corresponding conditions of the blood to be hereafter noticed. Endometrial inflamma- tions have been accordingly distinguished by some pathologists, as croupy, dysenteric, ca- tarrhal, and the like. The exudations of the fibrinous or croupous kind, which are found upon the inner surface of the inflamed uterus, exhibit sometimes great plasticity. These may occur in the form of isolated patches, or of more extensive invest- ments of a dense yellowish or greenish lymph, either firmly agglutinated to, or lying loosely upon, the sublying tissues. In inflammations of a less sthenic type, the exudation is softer and more gelatinous, and is often intermixed with serous and purulent fluids. Or the fibri- nous matter may be wholly wanting ; the in- flammatory products consisting then entirely of purulent discoloured and sanious exuda- tions, which, in cases that have been distin- guished as putrescence of the uterus, assume usually a greenish or dirty-brown coffee-co- loured aspect. The condition of the tissues, which are brought into view by removing or wiping away the above-mentioned products, exhibits corre- sponding variations. Beneath the coating of firm lymph, characteristic of uterine croup, the uterine tissue is merely softer and more spongy, and redder than usual; but in those forms of inflammatory action which rapidly pass into the purifbrm stage, the subjacent tissues become infiltrated and softened, so that they may be easily scraped away in the form UTERUS — (ABNORMAL ANATOMY). 703 of a discoloured flocculent pulp. This con- dition, in its highest degree, where the tissues appear macerated and deeply penetrated by the dirty-coloured fluids already described, at the surface, constitutes uterine putrescence. In addition to these products and results of inflammation, there may be found attached to the uterine surface fragments of an imper- fectly detached placenta, or blood clots and shreds of the deciduous lining, lying free within its cavity. These, by their decomposition within the uterus, whose cavity, from the moment of parturition, has ceased to be com- pletely closed against atmospheric contact, play an important part in the production of those septic and other infections of the blood which appear to form an essential part of all or nearly all puerperal inflammatory pro- cesses. Puerperal metrophlebitis. — Inflammation of the veins of the uterus occurs most frequently in combination with, and is, to a certain extent, secondary to, the conditions last de- scribed ; but it may occur also as a primary affection, and continue for a time the chief or only morbid state of the organ. The inflam- mation is seldom confined throughout to the veins of the uterus. It appears to commence in some of the orifices of the venous sinuses, which, after labour, terminate open mouthed upon the inner surface of the uterus, over the placental place, and thence spreading through those sinuses which occupy the uterine walls, it may extend to the spermatic and hypogas- tric veins and their tributaries, either upon one or both sides, and ultimately involve more distant vessels. The condition of the veins in uterine phle- bitis varies according to the intensity and duration of the inflammation. The inner coat may be pale or stained with the colour- ing matter of the blood. It may have lost its polish, or have become adherent to the con- tents of the vessel, where these are of a solid nature. The coats of the vessels affected may be thickened and opake, and the sur- rounding tissues infiltered by various co- louring fluids, or softened and in a state of putrescence. Regarding the contents of the vessels, these consist sometimes of firm plugs of fibrine coagulated from the blood, but more often of these in a softened grumous state, intermixed with portions of a yellow grey or whitish colour. The interior of such coagula may consist of a fluid not easily distinguishable from pus, but resulting from metamorphic changes in the fibrine, subsequent to its co- agulation within the vessels. Or the veins may be distended by a brownish sanies, or a yellow or greenish yellow viscid pus, so that upon section of the uterine walls numerous collections of the latter, resembling separate abscesses, are displayed. In the more severe cases of metrophlebitis the proper tissue of the uterus is deeply in- volved, being discoloured and in a state of disorganisation and putrescence throughout its entire thickness ; or exhibiting at different points smaller or larger abscesses, the con- tents of which may have been discharged into the general cavity, or form ramified sinuses or fistulae in the uterine substance. Such ab- scesses most probably arise from the suppu- rative inflammation extending beyond the coats of the veins, and involving the surround- ing parenchyma. Uterine phlebitis is often associated with inflammation of the uterine lymphatics (Lymphangioitis). These vessels, like the veins, become distended and varicose, and filled with a yellow or greenish puriform fluid, so that their course, together with that of the Fallopian tubes and ovaries, which are generally conjointly affected, may be easily traced into the corresponding hypogastric and lumbar lymphatic plexuses and glands. Puerperal metro-peritonitis, or inflammation of the peritoneal coat of the uterus, is asso- ciated with either or both of the foregoing affections, or it occurs as the primary local disease, and sometimes constitutes through- out the sole apparent morbid condition of the uterus. The inflammation may be limited to the peritoneal covering of the uterus and its appendages, or it may involve that of the en- tire pelvic and abdominal regions. The mem- brane itself, which often exhibits little vas- cular congestion, may have retained its polish, or may be covered by exudative products of very various characters. These may be only small in amount, and partially distributed, or abundant and copious. They consist of firm fibrinous concretions, or softer and more pulpy yellow or greenish exudations, consist- ing of coagulable lymph loosened by serous or purulent infiltration, or thick purulent fluid, or semi-fluid matter, or lastly serous or sa- nious fluids, the latter being often discoloured and rendered turbid by intermixture with the before-mentioned products, especially with fibrinous flocculi and puriform and sangui- neous effusions. These several pathological conditions of the uterus, which appear to be incompatible with the progress of those normal changes in the condition of the organ that constitute the process of involution (see p. 658.), are ac- companied almost invariably by a marked in- terference with those processes, so that the act of retrogression is either altogether ar- rested, or is in a high degree retarded. The foregoing puerperal affections of the uterus exhibit numerous points of great pa- thological interest. These, even in their milder forms, cannot be generally regarded as purely topical affections, for they commonly, in their progress, become associated with like conditions of other and often distant organs, whose connection with the original, or at least principal, seat of disease, can only be explained upon the hypothesis of a general dyscrasis of the blood. It is probable that in some cases, of those, for example, whose commencement is apparently dependent upon miasmatic influences, inoculation with cada- veric matter and the like, a primary infection of the blood precedes the development of the 704 UTERUS AND ITS APPENDAGES. topical condition, which may be viewed as the local expression of the former. In a large number of instances, however, the affection of distant parts may be considered as the re- sult of a secondary blood infection, i. c. of a poisoning of the blood by the introduction of some products from the original nidus of dis- ease, and particularly of venous pus and sanies in metrophlebitis.* The occurrences which immediately ensue upon the act of parturition, offer a ready ex- planation of the mode in which these and other extraneous matters may gain access to the general circulating fluid. For by the se- paration and removal of the placenta, together with a large portion of the decidua, the con- tents of the uterine cavity, consisting of va- rious puerperal products now exposed to the direct influence of the atmosphere, are brought into immediate relation with the patent ori- fice of the uterine veins terminating upon the placental space. Through these a copious reception of the exudated products of inflam- mation or of septic matters resulting from decomposition within the uterus, or of in- fecting matter derived from sources still more external, may readily take place, and so pro- duce either the primary or secondary dys- crases of the blood just noticed. It is also to be observed that independent of external sources of a blood dyscrasis, the latter may be occasioned by an accumula- tion of effete material, resulting from the arrest of those eliminative processes which constitute so large and important a part of the act of involution, and are always more or less impeded during puerperal inflammation ; or commonly by a reflux of pus and sanies formed in the larger venous channels in the case of metrophlebitis already mentioned ; while some of the worst forms of sepsis of the blood are those which result from deep pros- tration of the nervous system, occasioned by exhausting forms of parturition. The more important associated morbid pro- cesses occurring in connection with puerperal inflammation of the uterus, which it may be necessary here to notice, consist in exuda- tions into the larger serous sacs and synovial bursae, upon the mucous membranes, and in the parenchyma of various parts and organs ; and of deposits within the larger vessels, chiefly the veins leading from the uterus, or in the capillaries of organs often far removed from the original seat of inflammation. The effusions upon the peritoneum and pleura, and less frequently upon the pericar- dium, consist of fibrinous and croupous ex- udations, combined often with copious effu- sions of serous, purulent, or sero-purulent fluids, the latter being, perhaps, often the result of a breaking down or liquefaction of the croupous fibrine, and its conversion into a pus-like fluid. Similar collections are found in the synovial membranes of the larger joints, especially of the knee, shoulder, and hip. While upon the mucous surfaces, particularly * Rokitansky, op. cit. vol. ii. of the intestines, which are later affected than the serous structures, a less sthenic form of exudation is usually found, the effusion con- sisting here of serous, gelatinous, or purulent exudations (the former contributing largely to the production of puerperal diarrhoea), and of infiltrations into the mucous and sub- mucous areolar tissues. These various exudative processes, whose preference for particular tissues is probably in part determined by textural peculiarities, must be considered as efforts to eliminate the dyscrasial materials from the general blood mass, and they will continue until the ex- haustion of the crasis is complete. The qualitative variations observable in the products bear exact relation to the nature of the previous infection, and of the dyscrasis arising out of it. The character and mode also of the first effusions may materially affect those which occur at a later period ; for when the plastic products have been very abundantly and rapidly formed, and the defi- brination of the blood consequently very con- siderable, the extensive discharge of the fibri- nous element leaves the blood so attenuated, that the serous portion may then speedily transude through the walls of the capillary vessels, and in this way are produced those enormous collections of serous or sero-puru- lent fluids which sometimes rapidly form in the advanced stages of puerperal inflamma- tions, occasionally with but slight evidences during life of their occurrence. Of equal or greater interest are those associated pathological phenomena which are connected with secondary phlebitis, having its seat either in the larger veins, or in the capillary system of vessels. The veins nearest to the uterus are commonly first involved ; and from this point the inflammatory action may spread either by direct or interrupted continuity to more distant vessels, following, however, the reverse order of the circulation ; or it affects vessels remote from the original seat of inflammation, as in the capillary con- gestions, and inflammations of distant parts producing the lobular infarctions, and in more advanced inflammatory stages, the so-called metastatic abscesses and sloughs of various organs and tissues. The obstruction to the circulation arising in these cases from coagu- lation of fibrine within the vessels, and viewed by some pathologists as the cause, and' by others as an effect only of inflammation, may be perhaps regarded as a provision for limiting the spread of the infecting fluids, and pre- venting, to a certain extent, their introduction into the general circulation. In the larger vessels, especially in the veins nearest the point of primary infection, the fibrine is found under various conditions of coagulation, forming long cylindrical plugs, as in crural phlebitis, or shorter clots, whose red coloration depends upon the degree in which the blood corpuscles may have been incorporated in its several laminae, or their paler yellow colour, upon the absence of the same, and the consequent greater purity of UTERUS — (LIGAMENTS OF). the (perhaps effused) fibrine. The centre of these coagula may be found softened, and containing the creamy pus-like fluid which results from the molecular disintegration and liquefaction so commonly observed in fibrinous clots. Frequently the clots are of a less consistent texture, being of a dark brown or chocolate colour, or reduced to the con- sistence of a soft pulp. The coats of the veins may be thickened and adherent to the contained coagula, or covered by fibrinous laminae or merely blood-stained, or pre- senting no deviation from the natural state. LIGAMENTS OF THE UTERUS. These terms are applied to several dupli- catures of peritoneum, containing variable quantities of fibrous and muscular tissue, which serve to connect together the uterus and its appendages and to limit the motions of these parts within the pelvis. They are dis- tinguished as the broad, the round, the utero- sacral, and the utero-vesical ligaments. The broad ligament. — The fold of perito- neum in which the uterus is contained, after investing the fundus and anterior and posterior walls of the organ, passes off laterally in the form of a double lamina that extends from each uterine border horizontally outwards as far as the sides and base of the pelvis, to which it is attached. Thus a vertical septum is formed, which divides the cavity of the pelvis transversely into two chambers ; the anterior and shallower one containing the bladder, the posterior and deeper holding the rectum and a portion of the small intestines. The uterus occupies the middle of the septum, while the lateral extensions of it form the broad liga- ment of either side. Figs. 368. and 404. /., Attached to the upper border of the broad ligament are three folds, termed lesser wings. The central and superior of these, which is the largest, contains in its free falciform edge the Fallopian tube, and at its base a portion of the parovarium. It has been already described as the mesentery of the tube. The smaller pos- terior fold invests the ovary together with its proper ligament ; while the third or anterior fold is inclined obliquely towards the body of the uterus, and constitutes the covering of the round ligament. Between the lamina? which form the principal or lower portion of the broad ligament, as well as within the alae, are found the blood-vessels, lymphatics, and nerves which supply the uterus and its appendages, together with a variable amount of fibrous and un- striated muscular tissue that serves to connect the alminae together. This structure should be regarded as a me- sentery rather than a ligament of the uterus. It serves to invest the uterus and its appen- dages with a common peritoneal covering, and to protect these parts and attach them to the pelvis, as the mesentery attaches the intestines to the spine ; while the interspace of the folds suffices for the conveyance of vessels and nerves. The resemblance to a mesentery is more obvious in the bicorned and intestiniform uterus of the mammalia generally, as well as Supp. 705 of many other vertebrata in which it forms the mesometrium. The utero-sacral ligaments. — From the pos- terior wall of the uterine neck two falciform folds of peritoneum proceed towards the rectum. These are most easily seen when the parts are stretched. Between them lies the depression of variable depth known as the retro-uterine pouch, or space of Douglas. When the peritoneum is removed, these folds are seen to be occasioned by two correspond- ing bands of fibrous tissue, extending from the substance of the cervix backwards towards the sacrum, to which they are attached. Their strength varies considerably in different sub- jects ; so that when not much developed they may be overlooked. The importance of these ligaments, or rather fibrous bands, has perhaps not been generally sufficiently appreciated. From their position and connections it cannot admit of doubt that they are intended to re- strain the motions of the uterus, — to prevent it from being forced upwards in the act of con- junction, and especially to limit the descent of the organ in erect postures of the body. The utero-vesical ligaments. — Opposite to the point of junction of the body and neck of the uterus, where the peritoneum is reflected forwards on to the bladder, are commonly observed two slighter lateral folds, containing bundles of fibrous tissue. These constitute the anterior or utero-vesical ligaments. The round or sub-pubic ligament: ligamen- turn rotundum, ligamentum uteri teres. — This ligament consists of a flattened chord or band of muscular and fibrous tissue, which, traced from below upwards, proceeds from the in- ternal inguinal ring in a curved direction to- wards the superior angle of the uterus on either side, where it is inserted in front of and a little below the commencement of the Fallopian tube. (Figs. 404. and 418.) The ligament of the right side is commonly shorter than that of the left : hence it hap- pens that in pregnancy the uterus more often inclines to that side. According to Mr. Rainey*, the round ligament arises by three fasciculi of tendinous fibres : the inner one from the tendons of the internal oblique and transversalis muscles near the symphysis pu- bis ; the middle one, from the superior column of the external abdominal ring, near its upper part ; and the external fasciculus, from the inferior column of the ring, just above Gim- bernat's ligament. From these attachments the fibres pass backwards and outwards, soon becoming fleshy : they then unite into a rounded chord, which crosses in front of the epigastric artery, and behind the lower border of the internal oblique and transversalis muscler, from which it is separated by a thin layer of fascia continuous with the fascia transversali? : it then gets between the layers of peritoneum forming the broad ligament, along which it passes backwards, downwards, and inwards to the point of insertion already described. * On the Structure and Use of the Ligamentum Rotundum Uteri, Phil. Trans, p. 515. pt. ii 1850. z z UTERUS AND ITS APPENDAGES. 706 The round ligament is composed of smooth muscular fibre, derived from the uterus, and arranged in bundles, surrounded by connective tissue, of striated muscle, continuous with that of the abdominal parietes, and of blood-ves- sels, lymphatics and nerves. The peritoneal covering of the round liga- ment is occasionally prolonged in young sub- jects at its lower part through a portion of the inguinal canal, where it forms the canal of Nuck. This is usually obliterated in adults, where the arrangement of the tendinous part of the round ligament just described serves to close the in- ternal ring, and to prevent, in a great measure, the occurrence of inguinal hernia in the female. The persistence of this canal probably leads to the abnormal descent of the ovary into the labium, constituting hernia of the ovary (see p. 574.); — an occurrence exactly comparable with the normal descent of the testis into the scrotum of the male. VAGINA. NORMAL ANATOMY. Syn. Vuho-uterine canal. — The vagina con- stitutes a flattened cylindroid, extending from the vulvar orifice to the neck of the uterus. It lies entirely within the pelvis, between the bladder and rectum, running very nearly in the direction of the axis of the pelvic outlet, but having a slight curvature forwards. The orifice of the vagina is bounded anteriorly by the vestibule, laterally by the nymphae, and posteriorly by the hymen. The upper or blind extremity, termed the fornix, receives the va- ginal portion of the uterine neck, which is not placed exactly at the termination of the canal, but appears as if it were let into its upper wall (fig. 433.). Dimensions. — The vagina is capable of con- siderable extension. It varies in dimensions in different subjects. In the ordinary virgin state, the anterior wall, which is the shorter, measures, from the median tubercle of the vagina to the anterior lip of the uterus, less than two and a half inches ; and the posterior wall, from the centre of the vulvar orifice to the end of the fornix, three inches. The transverse diameter, in the natural state of the canal, which is flattened from before back- wards, so that the anterior and posterior walls are in contact, measures ordinarily one inch and a quarter. But when the canal is dis- tended, and after the birth of many children, these dimensions may be much exceeded. External surface. — The following are the relations of the external surface of the vagina. Anteriorly, it is connected to the urethra and base of the bladder by areolar tissue. Laterally, it is in relation with the root of the broad liga- ment and the pelvic fascia. Posteriorly, in the first part of its course, it is covered by the pe- ritoneum, forming the anterior wall of the retro-uterine pouch, or space of Douglas ; secondly, where the peritoneum ceases, and for about half its course, it is united to the rectum ; and lastly, it is separated from the latter by the thickness of the perineum. Composition. — The walls of the vagina are of variable thickness in different parts, the average being \'". They are composed of three coats. The outermost of these is formed of fibrous tissue, intermixed with an abundance of elastic fibre. Beneath this is a second or muscular coat, containing unstriped muscular fibre and fibre-cells, which, during pregnancy, undergo a development similar to that of the uterine fibre. The third, or innermost, is the mucous coat, composed of a dense connective tissue, with much admixture of elastic fibre, to which is due a great part of that elasticity and distensibility with which the vagina is en- dowed. Imbedded in the substance of the mucous membrane, which is covered by squa- mous epithelium, are numerous rnuciparous follicles. Internal surface. — Upon the inner surface of the canal the mucous membrane is thrown into folds, which, in the virgin, form numerous closely-set transverse rugae, that are arranged with a certain approach to regularity, and sometimes exhibit a central connecting line or raphe, forming the columnce rugarum, upon the anterior and posterior walls. At the sides of the vagina these folds are less prominent, and take an oblique or longitudinal direction. In some subjects the rugae are covered by, or are chiefly composed of, short, crowded ver- rucose papillae, intermixed with others more filiform. They become larger towards the vaginal orifice, where they sometimes take the form of little leaflets, resembling the smaller fimbriae of the Fallopian tube, especially about the meatus urinarius. After numerous acts of parturition, as well as from frequent inter- course, the folds become obliterated, and the inner surface of the vagina is rendered nearly or entirely smooth. Arteries. — A special artery usually exists for the vagina, which may arise either from the hypogastric, internal pudic, middle haemor- rhoidal, or even from the obturator. From one of these origins the artery descends along each side of the vagina, giving off in its course numerous branches, which inosculate in the recto-vaginal septum with those of the op- posite side. Near its extremity, the artery sends off a considerable branch to the bulb of the vagina, and after supplying the external organs, it terminates by inosculating with the artery of the opposite side, between the vagina and rectum. One or two separate branches are generally found to arise from the uterine artery. These descend between the bladder and the vagina, supplying branches to both those parts. An abundant and intricate net- work is formed in the vaginal walls by the ramifications of the smaller vessels derived from these sources, which interpenetrate the several coats down to the mucous membrane. Veins.— The veins which collect the blood from the labia, constrictor muscles, and mu- cous membrane of the vagina, and from the erectile tissue forming the vaginal bulb, unite to form a considerable plexus, especially around the vulvar orifice termed the vaginal plexus. From this plexus branches pass to VAGINA — (ABNORMAL ANATOMY). the vesical, and haemorrhoidal, and uterine plexuses ; the blood being finally collected by large veins which empty themselves into the internal iliacs. Figs. 482. and 483. The Lympatics are those which are common to the bladder, cervix uteri, and lower part of the rectum. They terminate in the pelvic glands. The Nerves are derived from the pelvic plexus, which contains a large proportion of tubular fibres, derived from the fourth and fifth sacral nerves. Uses of the vagina. — The vagina, during copulation, serves for the reception of the male intromittent organ, and for the lodge- ment of the seminal fluid in such a posi- tion as to facilitate the introduction of that fluid into the uterus.* During menstruation the vagina gives passage to the catamenia. In labour it transmits the foetus and secun- dines, and subsequently the lochia. ABNORMAL ANATOMY OF THE VAGINA. Anomalies. — Congenital absence of the vagina is not very rare. The entire vagina may be wanting ; so that on separating the labia no trace appears of a canal leading to the uterus ; or the canal may be so narrow as only to admit a probe or quill ; it may be very .short, terminating in a cul de sac, or it may open into the urethra or rectum. The latter malformation has not always prevented preg- nancy, even when combined with an entire absence of the external organs. A vertical septum occasionally divides the vagina through a greater or less portion of its course. This, when complete, produces the double vagina with double hymen (^g.461.). The septum may cease at a variable distance from the vaginal orifice, the fornix and upper part remaining single ; or, contrarily, the for- nix may show signs of division, while the lower part of the tube remains single. The septum is almost invariably in the median line, but the more frequent use of one or other channel in parturition or sexual con- junction may give to them an appearance of unequal development. Transverse membranous septa sometimes pass across and obstruct the vagina more or less completely. These, though they do not necessarily prevent impregnation, for they are seldom absolutely imperforate, may so far impede labour as to require division. They occur at various points within the canal ; at a short distance from the orifice, or as high up as the level of the utero-sacral ligaments. They consist, for the most part, of natural folds unusually developed, or they result from accident, as inflammation or injury consequent on difficult labours. Some of those constric- tions which occur near the orifice are doubt- less the consequence of inflammation of the vulva and vagina in infancy.-f- Atresia of the vagina may thus be acquired, or it may be * See IXSEMINATION, p. 671. f These cases are sometimes recorded as examples of imperforate hymen. 707 congenital. When the obstruction is com- plete, retention of the menstrual fluid results. Displacements. — The vagina may be alto- gether displaced from the pelvis, or it may simply have its normal direction altered within that cavity. Prolapsus of the vagina occurs sometimes alone, but it is more often com- bined with procidentia or inversion of the uterus (Jig. 469.). In any of these cases, if the prolapse is permanent, the vaginal surface loses altogether the character and appearance of a mucous membrane, acquiring a thick cuticular covering, and assuming the condition of ordinary integument. In retroversion of the uterus, the vagina is drawn upwards and for- wards, its extremity lying behind the pubic symphysis. (FigAGS.) "in hernia of the uterus, the vagina is diverted from the median line to- wards one or other side of the pelvis, and may be partly included in the hernial sac. Solutions of continuity. — Laceration of the vaginal walls may occur during obstructed la- bour, and is then frequently associated with rupture of the uterine cervix. Fistulous openings into the bladder, and sometimes into the rectum, are occasioned by sloughs con- sequent on protracted labour. Fistulous cloacae are also commonly formed in advanced stages of cancer (fig. 479.). Inflammation of the vagina. — Vaginitis. — This occurs both in the acute and chronic form. It may present the character of be- nignant catarrh, or of a specific blenorrhoea (gonorrhoea}. In the more acute form the mucous membrane is highly vascular, and is sometimes excoriated, from excessive shed- ding of epithelium. The discharge presents variable characters, from the viscid yellow puriform mucus, to the creamy, milk-hke, or thin, nearly watery, fluid (leucorrhcea). Croupous exudations occasionally form upon the vaginal mucous membrane, chiefly in con- nexion with typhoid exanthematous or puer- peral processes. Epithelial desquamaiion. — Occasionally the entire epithelial coat of the vagina is thrown off, forming a membranous cast of that canal. Several of these casts may be found, one contained within another. Their discharge may be accompanied by symptoms resembling those of dysmenorrhoea ; but more particularly by an intolerable itching or sensa- tion of crawling in the vagina. They are composed entirely of dense vaginal tessel- lated epithelium.* Serous and sanguineous infiltration into the mucous and fibrous coats of the vagina takes place occasionally during protracted labour, producing considerable tumefaction, and con- sequent narrowing of the canal. In this state * 1 have given a description, with several illus- trative figures, of these epithelial casts of the vagina, some of which include also the epithelium of the vaginal portion of the cervix uteri, in Beale's Ar- chives of Medicine, for April, 1858. I suspect that the nature of these has been overlooked, and that they, have been confounded with the true dysmenor- rhoeal membranes which consist of the lining mem- brane of the uterus. See^fy. 443. z z 2 708 UTERUS AND ITS APPENDAGES. the vaginal walls are easily lacerable, or if subjected to continued pressure pass readily into gangrene. Abscess forms occasionally in the vaginal walls, but many of the abscesses which burst into that canal have their origin in pelvic cellulitis, or in inflammation of other struc- tures external to the vagina. Ulceration. — The minute aphthous ulcers which are dotted over the surface of the va- gina originate in follicular inflammation. The more extensive and irregular ulcers, except those which form upon the more exposed parts when the vagina is inverted, as in proci- dentia uteri, are usually either syphilitic or cancerous. Gangrene of the vagina occurs in conjunc- tion with gangrene of the vulva in septic puer- peral processes ; or it results from pressure in protracted labour. Spontaneous gangrene occurs also occasionally in infants and young children. Cysts and tumours. — The former, if of small size, may result from obstructed mucous fol- licles ; but more often the larger cysts arise in situations external to the vagina, and pro- trude into its canal. In the same way, fibrous or osseous tumours growing from the perios- teum or ligaments of the pelvis, ovarian, or even uterine tumours may, by pushing before them the walls of the vagina, protrude into the canal. Vaginal cystocele and rectocele occur in a similar manner. The tumours which lie free within the vagina are chiefly uterine polypi, or cancerous tumours of the cervix or of the vagina itself. The uterus, when partly in- verted, also forms a tumour occupying the vagina. Cancer may originate in the vagina, although it more often constitutes an extension of the same disease from the uterus. In either case it appears most commonly as medullary can- cer, taking the form of tuberculated masses or ridges, which narrow or obstruct the passage, and quickly pass through the stages that cha- racterise the ordinary progress of uterine can- cer. The surrounding parts become infiltrated with cancer matter, and the vagina is fixed in the pelvis, ulceration of the walls and fistulae resulting. Occasionally, at the commencement, this disease appears in the form of soft, rapidly- growing papillary structures, springing from the upper and posterior wall of the vagina (villous cancer). EXTERNAL ORGANS OF GENERATION. SYN. Vulva. Pudendum. — These parts per- form subordinate offices in the act of repro- duction. They are in no way concerned in gestation, and only slightly in menstruation and parturition. They are associated with the vagina in the act of copulation, which has for its object insemination, or the con- veyance of the seminal fluid to the internal or formative organs. The parts which serve to establish this relation between the sexes, with the exception of the vagina, are placed external to the body, and are attached to the front of the pelvis. They are included under the general term vulva or pudendum, which extends from the mons veneris to the perineum. The vulva consists of the follow- ing parts, viz. labia, clitoris, nymphae, vesti- bule, vaginal orifice, and hymen. THE MONS VENERIS forms a slightly rounded or flattened eminence, of triangular outline, covering the symphysis and horizon- tal rami of the pubes. In fat subjects it is separated from the abdomen by a transverse furrow. It is composed of adipose and fibrous tissue, covered by integument. The latter contains many sebaceous and hair follicles. The hair is not developed until the age of puberty. Fig. 480. External organs of generation, and commencement of vagina. (After Huguier.} I, labium of left side (that of the right side is divided and partly removed to expose the vagina and vulvo-vaginal gland) ; n, nympha ; c, glans clitoridis ; p c, preputium clitoridis ; v, vestibule ; u, orifice of urethra; va, vagina; g, vulvo-vaginal gland, or gland of Bartholin and Duvernay ; d, duct of the same. THE LABIA, termed also labia majora, to distinguish them from the lesser labia or nymphae, are two symmetrical tegumental folds(j6g. 480. //), placed one on either side of the rhna or fissure which leads to the vagina. The labia vary considerably in size and form in different subjects. In stout adults they are full and fleshy, closing the vulvar orifice, and con- cealing the rest of the generative organs, which they serve to protect. In the aged the labia become shrivelled and the nymphae pro- trude between them, as they also commonly do in infants and young subjects. The outer surface of each labium is composed of com- mon integument, which at the age of puberty EXTERNAL ORGANS OF GENERATION. 709 becomes covered with hair. Along the line of apposition of the two labia, where the rima is formed, the hair and integument cease, and the mucous membrane common to the rest of the generative canal commences. From this point inwards the surface of the labium is smooth, of a reddish or pink colour, and is here furnished with numerous muciparous and sebaceous follicles, which bedew the parts with an odorous secretion, and preserve their constant moisture. The labia are united above by a slight fremdum, termed the ante* rior commissure, while below they are con- nected, at the anterior margin of the perineum, by a broader posterior commissure. When the parts are here drawn asunder, a second fold appears within the former, just below the entrance of the vagina. The transverse boat- shaped furrow between these constitutes the fossa naviculnris. Beneath the cutaneous and mucous covering of the labia is found a layer of dartoid tissue, the rest of their substance being formed of loose fibrous and adipose tissue. The labia represent the scrotum, which in the early foetus is divided into two halves. A raphe indicates in the male the line of their subsequent confluence. In the female the two halves remain permanently separate. The normal descent of the testis into the scrotum in the male, about the seventh month of intra-uterine life, is represented by the ab- normal descent of the ovary into the labia of the female which constitutes ovarian ingui- nal hernia. (See p. 574.) When the labia are drawn asunder, the clitoris, the vestibule, nymphae, and vaginal orifice are brought into view. THE CLITORIS (Jigs. 481. and 482.), in general form and composition, resembles, on a diminutive scale, the penis, but it is deficient in some of the parts which compose the latter organ. The clitoris lies in the upper part of the vulvar fissure, concealed between the labia, and encased in a fold of mucous mem- brane, the lower border of which forms a hood or prepuce (preputium clitoridis) (Jig. 480. pc), that terminates just above the superior com- missure of the nymphae, and allows the ex- tremity only of the organ to appear. When this covering is removed, the clitoris is seen to consist of the following parts : viz. a small imperforate glans (fig. 481. c), com- posed of spongy erectile tissue, and covered by a highly senwtive mucous membrane, which is abundantly supplied with nerves ; this terminates the free extremity of the organ : a body (fig. 481. b), consisting of two cor- pora cavernosa, united along the median line, and invested by a fibrous tunic. The body extends upwards and backwards to a point a little above the centre of the pubic arch. Here it makes a sudden downward curve, and, after dividing into two crura, is attached by these beneath the iscio-pubic rami of either side. Opposite the point of curvature, a flat- tened suspensory ligament attaches the body of the clitoris to the pubic symphysis. Two ischio-cavernous muscles (erectores clitorides), composed of striped muscular fibre, are in- serted into the crura. They have the same relations, and, according to Kobelt, are fully as long as in the male (fig. 483. n). Blood-vessels. — Two dorsal arteries (fig. 481. K), running along the upper surface of the Fig. 481. The clitoris (enlarged 4 diameters.) (After Kobelt.) a, body ; b, angle or curvature ; c, glans ; d, vena dorsalis; e, superficial veins emerging from the root of the glans, and fg, veins of deeper origin. These transmit the blood to the vena dorsalis ; h, dorsal artery; Hi, dorsal nerves ; k, the venous plexus, termed pars intermedia (shown also at d, Jig. 482., and e,fig. 483.); /, communicating venous branch between the glans clitoridis and pars inter- media ; m, ascending venous canals proceeding from the pars intermedia (k) to the under surface of the body of the clitoris ; n n and o, lateral branches of communication between the vessels last named and the vena dorsalis ; p, veins from the labia, and r, from the nymphae and frenulum clitoridis, which enter the pars intermedia ; 7, arterial branches cor- responding with the pars intermedia and commu- nicating veins ; s, frenulum clitoridis. clitoris, supply the glans, from which the blood is again collected by superficial veins, emerging from the root of the glans at e, and by others having a deeper origin at f. These transmit the blood to the vena dorsalis, d. From the cavernous bodies the blood is also collected by a series of vascular canals, of which an account will be presently given. Nerves. — The clitoris is richly endowed with nerves, i i, which are relatively three or four times larger than those of the penis. They pass along the sides of the clitoris, each dividing usually into three branches, the ulti- mate ramifications of which lose themselves z z 3 710 UTERUS AND ITS APPENDAGES. partly in intricate plexuses within the glans, and partly in terminal loops upon its mucous covering. Development. — In the foetus of three to four months, the clitoris is scarcely distin- guishable from the penis. But about the latter period the proportionate retrocession of the one organ, and the increased development of the other begin to be apparent. In the male, the groove along the under surface of the penis is closed in, and at the same time the raphe of the scrotum is formed ; while in the female, the parts corresponding with the bulb and corpus spongiosum urethras remain open, and constitute a portion of the rima. These lie in two halves on either side of the entrance of the vagina, while the urethra is developed independently of them. NYMPHS. — Labia minora v. internet, — These consist of two thin and slightly fleshy folds of mucous membrane (fig. 480. 72), somewhat re- sembling a cock's comb, which lie on either side of the entrance to the vagina, extending from the clitoris downwards, as far as the middle or lower border of that orifice. The nymphae commence above by two roots. The inner one, thin and membranous, is inserted beneath the glans clitoridis, and forms with its fellow a kind of frenum. The outer one, more fleshy, passes round the glans, and by its junction with the corresponding portion of the opposite side constitutes the preputium clitoridis (fig. 480. p c) already described. From these two roots or origins each nympha extends downwards and outwards, forming a thin prominence, of variable extent in different subjects, until it becomes merged in the labium of the corre- sponding side, near its posterior extremity. The nymphae are composed almost entirely of mucous membrane, which on their outer side is continuous with that of the labia, and upon their inner surface with the lining mem- brane of the vagina. Various uses have been assigned to the nymphae. One of these is that they serve to direct the stream of urine issuing from the nrethral orifice, as suggested in the classic allusion to the sea nymphs pouring water from a vase which is implied in their name. Another supposition is that the nymphae aid the enlargement of the vaginal orifice, by be- coming unfolded at the time of labour, although no such unfolding can be absolutely observed. It is more probable that their office is that of extending the secreting and sensitive surfaces at the entrance of the vagina. The nymphas correspond with that part in the male which forms the tegurnental covering of the urethra, but which remains ununited in the female along the median line. THE VESTIBULE. — This term has been employed in two senses. In its widest sense it includes all the parts which immediately sur- round the vaginal orifice. In a more restricted meaning, it is limited to that triangular patch of mucous membrane (Jig. 480. v) which fills up the summit of the pubic arch. In the latter sense the apex of this triangle is formed by the clitoris, the sides by the upper halves of the nymphae, and the base by the roof of the vaginal orifice. In the centre of the base is situated the mcatus urinarius, which forms here a slight prominence (fig. 480. u), at a distance of one inch behind the clitoris. Immediately below this point the anterior column of the vagina terminates in a prominent bulb or tubercle, marked usually by numerous trans- verse folds. ORIFICE or THE VAGINA, AND HYMEN. — Immediately below the vestibule, and between the nymphse, is the orifice of the vagina (fig, 480. va), which, in its undistended state, has the form of a vertical fissure, especially in women who have borne children, but in virgins it is more constricted and circular, and is further narrowed by a fold of the vaginal mu- cous membrane, the hymen, which either en- circles or semi-encircles the orifice. As some important questions in obstetric and forensic medicine relate to this membrane it will receive here a more particular examination. The hymen, regarded in an anatomical point of view, possesses no peculiarity or speciality by which it is essentially distinguished from many like structures in other parts. It belongs to the same class of formations as the valvulae conniventes of the intestines, and the frill-like folds of mucous membrane which not infre- quently surround the terminal orifices of mu- cous tubes. In the foetus such folds are seen with various degrees of distinctness at the ter- mination of the urethra, vagina, and often of the rectum. The lower end of the vagina, in the foetus invariably terminates in a marked projection outwards of the mucous lining of the tube. It takes the form of a laterally compressed conical fold, the base of which is continuous all round with the vaginal walls, but the apex is directed forwards. Its centre exhibits a vertical slit-like orifice, the direction of which is apparently due to the lateral com- pression of the nymphae and labia, between which it lies. This is the hymen. In ad- vanced foetuses it is scarcely distinguishable in form, and only to a certain extent in size, from the similar conical termination of the cervix uteri, which projects into the vagina, as the hymen does between the nymphae. The vaginal portion of the cervix uteri and the hymen both constitute invaginations or intussusceptions at two different points of the same mucous tube, — the one marking the division between the uterus and the vagina, the^ther between the latter and the external parts. The chief dif- ference between them is that the direction of the orifice in the former is transverse, and in the latter vertical. Such is the condition of the hymen during foetal and infantile life. But as growth advances the posterior half becomes much more developed than the anterior, just as the posterior half of the uterus, the poste- rior lip of the cervix, and the posterior wall of the vagina, are commonly larger and more developed than the corresponding anterior halves. Thus it happens that in adults the hymen presents usually theformof acrescentic or seinilunar fold, the concave border of which EXTERNAL ORGANS OF GENERATION. 71 is directed upwards or forwards, while that which had been in the fetus, the upper half, has now become unfolded or lost among the plaits of mucous membrane, situated at the upper part of the vaginal entrance. This, because it is the most constant, has been usually regarded as the typical form of the hymen. But the foetal form is also often re- tained, namely, the circular fold of mucous membrane, which, as the parts become more expanded, acquires a round rather than a slit- like aperture. If, however, the folds of the mucous membrane lining the vagina are pro- fusely developed, then the hymen also exhi- bits the form not so much of a distinct membrane as of an irregularly constricted ori- fice, the sides of which are puckered or gathered into plaits, so as nearly to close the vaginal entrance. And this also is a very common condition of the part, especially in young subjects. The varieties, therefore, in the hymen which anatomists recognise, such as the crescentic, circular, cribriform, and the like, become easily explicable. They all proceed apparently from a common starting point, but differences in the degree of development, or accident, may determine the permanent form. The half- circle and crescent result from a normal deve- lopment of the posterior, and a corresponding retrocession of the anterior, moiety of that conically projecting mucous fold which is more or less distinct in every fcetus. The hymen with a central or nearly central circu • Jar orifice, results from a flattening down and retiring within the vaginal orifice of the cone ; the retiring naturally following upon an expan- sion of the vaginal walls as growth advances. The appearance of a notched margin to the cen- tral aperture is produced by the prominent edges of the terminal vaginal folds, which are in some subjects more profusely developed than in others. The cribriform hymen pro- bably results from an abnormal cohesion of these notched edges, in such a manner, that small apertures are left between them, and the completely imperforate hymen by an en- tire adhesion of the margins of the orifice, the result sometimes of inflammation in in- fancy. The hymen, however various its forms may be, consists of a double layer of mucous mem^ brane, containing between its laminae a small quantity of fibrous tissue and blood-vessels. It is of variable degrees of thickness, being in some subjects very strong and tough, and in others forming a very slender lamina. Its situation is at the entrance of the vagina. Although the depth at which it is placed within the vulva varies in different subjects, according to the thickness of the labia, and the size of the nymphas and vestibule. Occa- sionally, as already stated, one or more plicae of the vaginal mucous membrane, more than usually developed, form constrictions at a higher point within the canal, but the term hymen cannot with propriety be applied to any of these. The presence of the hymen, although it raises a strong probability of virginity, jet affords no certain evidence upon that point, nor does its absence establish the contrary. The hymen is commonly said to be ruptured on the occasion of a first complete intercourse, but the expression unfolded would probably, in many instances, more accurately represent the mode of its disappearance. Whenever the hymen presents any considerable mem- branous surface, doubtless a real laceration occurs, but in the cases in which it takes the form of a crescentic fold, or of a puckered rosette, instead of being lacerated, it probably becomes unfolded or flattened out, and so dis- appears, just as the ordinary vaginal folds are obliterated, by frequent intercourse or by parturition, without any rupture. Upon the presumption that the hymen is always lacerated a certain hypothesis has been raised, namely, that the tittle fleshy bodies occasionally observed near the orifice of the vagina, termed carunculce myrtiformes, consti- tute the remains of that membrane. But, notwithstanding a great amount of evidence that has been collected regarding the myrti- form bodies, it cannot be shown that these are anything more than accidental and uncertain formations, having nothing necessarily to do with the hymen. The Kymen may be broken by accident, or may become obliterated by the frequent em- ployment of vaginal injections, and in other like modes. Or, from constant leucorrhoea, the parts may become so relaxed that a dis- tinct membranous fold can be no longer dis- cerned at the vaginal orifice, although there may have been no loss of virginity. On the other hand, impregnation may take place without destruction of the hymen, which has frequently been found entire at the time of labour, and even in women affected by sy- philis.* Sebaceous and Muciparous Glands and Fol- licles of the Vulva. -^ The sebaceous follicles correspond with the male preputial follicles. They are scattered over the nymphae, clitoris, and inner surface of the labia. Their secretion contains butyric acid and has a strong and somewhat ammoniacal odour. This occasion- ally becomes highly irritating, especially when cleanliness is neglected. The muciparous follicles are arranged in groups, the principal ones being situated upon the vestibule (vestibidar follicks, fig. 480. v), around and upon the sides of the meatus urinareus (urethral follicles, fig. 480. &), and at the sides of the entrance of the vagina (lateral follicles of the vaginal orifice, fig. 480. va}. The muciparous follicles are composed of a delicate vascular mucous membrane arranged in the form of short mucous crypts, or con- sist of simple or branched tubules ending * In a case of extensive syphilitic periostitis which came under my notice, in a woman thirty years of age, who had previously been a prostitute, a tough membranous circular hymen closed the orifice of the vagina so completely that the tip of the fore finger could scarcely be inserted within it. z z 4 712 UTERUS AND ITS APPENDAGES. in a cul-de-sac. The vestibular follicles are of the former kind and the urethral of the latter. All these vulvar follicles secrete a viscid mucus, the quantity of which becomes consi- derably increased under excitement or irrita- tion. It serves to lubricate the several parts of the vulva. The vidvo-vaginal glands, termed also the glands of Bartholin and of Duvernay, consist of two conglomerate glands of the size of a haricot bean, variable in form, and of a pale reddish yellow colour, which are placed one upon each side of the vagina near the entrance (Jig. 480. g). They are lodged beneath the superficial perineal fascia, having their inner side united to the vagina by areolar tissue, and their outer surface in relation with the con- strictor muscle of the vagina. The lobules composing this gland send off tubules which at its upper and fore part unite to form an excre- tory duct that proceeds horizontally forwards as far as the vaginal orifice, upon the side of which it terminates just within the nymphae and externally to the hymen. The orifice of the duct (d) is covered by a falciform fold of mucous membrane, which renders its discovery sometimes difficult. This gland secretes a viscid fluid resembling somewhat the prostatic fluid and having a pe- culiar odour. Under excitement its secretion is rapidly formed and, like the contents of the salivary duct, is sometimes emitted in a jet. This gland is probably homologous with Cow- per's gland in the male. In infancy and early life it is very small, attaining its full develop- ment in the adult, and again diminishing and even disappearing in old age. When the labia and nymphae are abscised a series of vascular erectile structures are brought into view, which, together with a special muscle, surround the vaginal orifice. These are the vestibular bulb, pars intermedia, and constrictor vaginae muscle. Pars intermedia. — From the dorsal vein of the clitoris (fig. 481. d) several branches (n,n) pass downwards round the sides of the organ • to communicate with a double row of closely- set venous canals, which commencing ante- riorly at the glans extend backwards to the root of the clitoris in the form of a frill that completely occupies the angle contained in the curvature of the organ (fig- 481. m and fig. 482. /). These venous canals enter the body of the clitoris by a double row of apertures along its under surface. They represent the communicating veins between the corpus spongiosum urethras and the corpora caver*- nosa penis. After receiving branches from the glans clitoridis (fig. 481. /), nymphae (r), and labia (/;), they form on either side a series of convoluted veins (£), which spread- ing downwards and outwards ultimately termi- nate below in the bulb of the vestibule (fig. 482. and 483. «). This is the structure termed by Kobelt the pars intermedia. It corresponds with the corpus spongiosum ure- thrae of the male, which in the female remains divided into two halves. The arteries of this Fig. 482. Lateral view of the forepart of the pelvis, attached to which are the clitoris and the vascular and erectile structures connected with it. (After Kobelt.) a, vestibular bulb of the left side ; b, veins passing off from the lower and posterior border of the bulb, to the pudendal vein ; c, similar veins communica- ting with the hamiorrhoidal ; c', the spot at which the veins of the vestibular bulb pass off to the vagina ; d, pars intermedia ; e, glans clitoridis ; f, ascending communicating veins proceeding to the body of the clitoris ; g and i, lateral communicating branches between the vena dorsalis clitoridis and pars intermedia ; h, vena dorsalis ; k, bend of the clitoris ; I, crus clitoridis ; n, vulvo-vaginal gland. structure (fig. 481. but it becomes gradually attenuated towards the margin, which is slightly rounded, measuring here only 2 — 4'" in thickness. The weight of the placenta ranges from 15 — 30 oz. or more. Foetal surface. — Upon the fetal surface of the placenta are observed portions of the amnion and chorion, together with the root of the funis and the principal branches of the umbilical arteries and vein. Amnion. — The amnion (Jig. 484. am)y after furnishing the outer covering of the funis, 716 UTERUS AND ITS APPENDAGES. passes off in all directions at the root of the cord, and spreads in a thin opaline lamina over the fetal surface of the placenta, to which it slightly adheres. In some cases, especially when 'the umbilical vessels divide before entering the placenta, the amnion has no attachment at all to the latter. The am- nion of the placenta does not differ in any respect from the rest of the amniotic sac, of which the placental portion constitutes about one third. Upon its foetal surface is a single layer of flattened polygonal cells filled with delicate fat granulations. Chorion. — The same proportion of chorion as of the amnion, namely, about one third of the entire superficies, is appropriated to the placenta. This, however, is not, like the amnion, simply an apposed membrane. It enters into the composition of the organ, and gives strength to it (fig. 484. ch). It sustains and transmits the branches of the umbilical vessels (vf), which adhere to, and ramify upon, its foetal surface, between it and the amnion. This face of the chorion is united to the amnion by a thin and easily separable layer of soft pulpy tissue, constituting a portion of the tunica media of the ovum, while the reverse surface, which forms, as it were, the base or floor of the placenta, bears the numerous tufts or villi that make up the bulk of this organ. Fcetal blood-vessels. — The blood-vessels of the placenta which belong to the foetus are branches of the two umbilical arteries, and of the single umbilical vein. These, as just stated, ramify in large trunks over a consider- able portion of the fetal or under surface of the placenta, before they penetrate the cho- rion to gain the interior of the organ. When the foetal vessels have been injected from the funis, their course upon this surface of the placenta is easily traced. Within the root of the cord, and at a distance of one inch from its insertion, the two umbilical arteries com- municate together by a cross branch half an inch in length. Immediately on reaching the placental surface, each artery bifurcates, the branches passing off in opposite directions. A second bifurcation takes place, in the same manner, about half or three quarters of an inch from the first. And lastly, a third, at distances ranging from one to two and a half inches. Each of these dichotomous divisions is at first more or less abrupt and opposite, the vessels afterwards bending, and taking a slightly divergent or parallel course, or even somewhat approximating. After the third bifurcation, the vessels again divide and sub- divide, but now at acute angles ; their extre- mities become lost, when they are reduced to the size of a crow quill, by dipping down sud- denly, and passing through the chorion, to enter the substance of the placenta at dis- tances varying from an inch to an inch and a half from its border. A small branch, how- ever, in continuation, often runs on nearly to the edge. Lateral branches, of the same size as the terminal subdivisions, also leave the main vessels in all parts of their course, and dip down into the placental substance. The branches of the veins, about sixteen in number, which return the blood from the in- terior of the placenta, emerge from its sub- stance close to the points of entrance of the arteries, and take a less tortuous course than the latter. They, however, accompany these vessels, but more in the form of radiating lines, which proceed towards the root of the funis, passing under the arteries, and ulti- mately uniting in the single umbilical vein. The varieties in the form of the placenta already noticed are apparently dependent upon certain modifications in the development and arrangement of these vessels, which are like- wise very variable, although the same primary divisions are noticeable in all. In the circular placenta the root of the cord is inserted into, or near, the centre. In the oval form it is attached to the smaller extremity forming the placenta en raquette. In the reniform and cordate placenta, the insertion is likewise more or less lateral. Lastly, when the vessels of the cord divide before arriving at the surface, they form the placenta en parasol. Uterine surface. — The reverse or uterine surface of a placenta which has been sepa- rated from its attachment, as in natural labour, is rough, and is divided into numerous rounded oval or angular portions, termed lobes or co- tyledons. These vary from half an inch to an inch and a half in diameter. The whole of this surface consists of a thin, soft, and somewhat leathery investment of deciduous membrane, which dips down in various parts to form the sulci that separate the cotyledons from each other. This layer is a portion of the decidua which, as long as the parts are in situ, constitutes the boundary between the placenta and the muscular substance of the uterus, but which at the time of labour be- comes split asunder, so that while a portion is carried off along with the placenta, and constitutes its external membrane, the rest remains attached to the inner surface of the uterus. This layer serves as a medium by which the uterine arteries (fig. 484. a a) and veins pass from the uterus into the placenta. Numerous valve-like apertures are observed upon all parts of the surface. They are the orifices of the veins which have been torn off from the uterus. A probe passed into any of these, after taking an oblique direction, enters at once into the placental substance. Small arteries, about half an inch in length, are also everywhere observed embedded in this layer. After making several sharp spiral turns, they likewise suddenly open into the placenta. These are the uterine vessels, which convey the maternal blood to and from the interior of the placenta. Circumference. — The margin of the pla- centa is bordered all round by the united membranes which enter into its composition. Here the amnion and chorion, after lining the fetal or concave surface, come into contact with the decidua which covers its uterine face, and the three membranes then pass off to- gether to enclose the liquor amnii and foetus. At this part the decidua is always most dense. PLACENTA — (NORMAL ANATOMY). Partly within its substance is formed an in- complete sinus, the circular vein or sinus. This constitutes an interrupted channel, which more or less encircles the placenta. Several orifices are observed in its walls. Some com- municate directly with the interior of the pla- centa, and others with the uterine sinuses. 717 Substance. — When a clean section has been made through the placenta (fig. 484.), the two surfaces already described are observed to enclose between them a soft spongy sub- stance, which is made up principally of count- less ramifications of the foetal villi. These are attached at their base to the chorion, from Fig. 484. Vertical section of the walls of the uterus with the placenta attached. From a woman in the thirtieth week of gestation. (After Wagner.} The length of the lines uu, serves to distinguish the uterus; p, the placenta, and dd, the decidua. To the right of the figure the decidua is separated into ud, uterine decidua, and dp, decidual prolongations •which form the dissepiments dividing the placenta into lobes ; f, funis ; am, amnion ; ch, chorion ; vf, foetal blood-vessels (divided) upon the surface of the placenta; vv, villi ; us, uterine sinuses; a a, curling arteries in the substance of the uterus. which they spring, while their opposite extre- mities are united to the decidual layer form- ing the uterine boundary of the placenta. The interspaces left between the villi and their ramifications form what have been termed the cells of the placenta. They are widest between the roots of the villi, and much smaller between their extremities. In these spaces the maternal blood circulates. When injections are thrown into the placenta from the uterine arteries or veins, these spaces become filled, and the mass, when broken, exhibits a peculiar granular appearance. Dip- ping down among the villi, and reaching in some cases as far as the foetal surface of the placenta, are numerous sheet-like prolonga- tions of decidua (fig. 484. dp). These con- stitute the dissepiments which separate the entire mass into its several lobes or cotyle- dons. At the placental margin, the decidual layer generally dips under the villi, forming a return end or border, which is directed in- wards, and is attached at a distance of 3 — 4"' from the margin to the outer surface of the chorion. The exact relation of the decidua to the villi, in various parts of the placenta, will be better understood after a more minute description has been given of each of these structures. The tufts and villi. — A placental tuft has been often compared to a tree. It con- sists of a trunk giving off numerous branches, which ultimately end in finer subdivisions or villi (fig. 484. vv and fig. 485. a). The trunks may be said to take root in the cho- rion, from which they spring, while the branches and finer subdivisions spread la- terally and upwards, until they come into contact, at their sides, with the adjacent tufts and villi, and above with the decidua which bounds the placenta towards the uterus. Many of the villi, instead of branching like trees, proceed thread-like from the floor to the roof of the placenta, only sending off short knotty side branches. The tufts are so closely set, that their forms cannot be readily discerned until they are floated out in water. The stems are tough and fibrous, or coriaceous, while the branches and finer villi, though strong, are of a more brittle texture. When one of these is broken offj and examined by the microscope, it presents the following characteristics — the subdivi- sions are abrupt, contorted, and singularly 718 UTERUS AND ITS APPENDAGES. devoid of symmetry ; from all parts of their surface spring numerous short pullulations, which render them knotty and uneven. Every villus is composed of two distinct parts, viz. an outer leathery sheath, and an inner softer and vascular structure, which is contained within the former like a finger en- cased in a glove. The distinction between these two structures is not easily observed, except in parts where the outer sheath has been accidentally broken off, leaving the more pulpy internal substance exposed. Or in cases where the placenta has become stale by keep- ing for a few days, when the inner portion by shrinking has retired from the end of the vil- lus, so that a small interspace has been here left (fig. 485. b). When a terminal tuft so prepared is viewed by transmitted light, under slight compression, the outer case is seen to consist of a trans- parent non-vascular structureless membrane, embedded in the substance, or attached to the inner surface of which are numerous flattened spheroidal cells, forming generally a single layer. In the apex of a growing tuft, or forming a distinct bud projecting from its extremity, may be often observed a group of similar cells which appear to be passing off from a spot in the centre of the mass.* These cells perform important parts in the growth and offices of the villi, which will be presently noticed. The internal portion (fig. 485. 6) consists of a soft and pulpy structure which envelopes the blood-vessels of the villi. In its substance also are embedded numerous cells of a similar nature to those observed in the structure- less sheath. Termination of the foetal vessels. — The ar- rangement and terminal divisions of the blood- vessels within the villi varies considerably according to the age of the placenta. The following distribution is observed from the third to the sixth month (fig. 485. a). Each villus contains one or more arteries and veins, together with numerous capillaries. The ar- teries pass up the centre of the stem, and divide into branches according to the number of the terminal subdivisions. Within these the branches split up into numerous capilla- ries, which present various forms of arrange- ment, in some parts resembling Malpighian bodies, and in others the arrangement of pul- monic capillaries. From these capillaries the blood is collected by veins which pass back through the tufts accompanying the corre- sponding arteries. All these vessels, with their subdivisions, are enveloped and sup- ported by the pulpy granular substance that forms the interior of every villus (fig. 585. b). Towards the end of pregnancy, the true capillaries of the villi gradually disappear, so that in a placenta at term the blood-vessels present the condition accurately described by C. H. Weber and Goodsir. A single vessel generally enters each terminal tuft, and after * J. Goodsir. Anatomical and Pathological Ob- servations, 1845. Fig. 485. a, terminal villus of a foetal tuft, from » placenta of six months. The arteries, veins, and capillaries are minutely injected. The latter, which disappear towards the end of gestation, are here very abun- dant. The arteries and veins occupy the centre, and the capillaries the surface, of the tuft, immediately beneath the non-vascular sheath. The nucleated non-vascular sheath is shown at b, separated from the internal softer structure in which the vessels ramify. (Ad Nat.") forming an open loop, it returns again, either dividing within the villus, or leaving it as it entered. Or a single vessel may enter, and retire from two or more villi, before it termi- nates in a principal vein. Many modifications occur in the forms of the loops, which may be simple, compound, wavy, or much contorted, and in parts varicose.* Such, then, are the structures belonging to the fcetus which are brought into contact with the maternal blood in the interior of the pla- centa, viz. the portion of chorion that forms the floor of the placenta, and the tufts or villi which spring from its surface. The office of the former is simply mechanical in confining the maternal blood to its proper course, and preventing rupture of the organ ; the latter constitutes the potential portion of the pla- centa. On the other hand, the sole parts belonging to the mother, the existence of which can be anatomically demonstrated in the substance of the placenta, are formed out of the decidua. The decidua. — A general description of this membrane, as it forms the roof of the placenta, and sends off dissepiments into its substance, has been already given. It only remains to * These are the only terminations of the fcetal vessels of the placenta which have been hitherto described. The true capillary system disappears towards the end of gestation, and apparently, on this account, has escaped the attention of observers, as far as I am aware, except Schrceder van der Kolk, who, in his recent work, has described and figured them in a placenta of three months. Scanzoni also (Lehrbuch der Geburtshilfe,^. 99.) reproduces the figure of Meckel and Gierse, in which the capilla- ries have evidently been injected ; but this is given as an example characteristic of a dropsical placenta, and not as representing a normal state. PLACENTA — (DEVELOPMENT). 719 explain the exact relations of this structure to the villi, within the placenta. All the extre- mities of the villi which are sufficiently long to reach across the placenta from the chorion to the opposite surface formed by the decidua, become firmly attached to the inner side of the latter. This attachment takes place not by any actual perforation of the decidua, but by the ends of the villi being simply inserted, in an early stage of the formation of the pla- centa, into little shallow pits or cup-like de- pressions in the decidual substance, into which they are received, and from which they may be withdrawn.* In other cases, the ends of the villi become blended with the decidua, to which they are apparently fixed, by a growth of decidual cells. These attachments are for the purpose of giving strength to the placenta, and of mechanically supporting the villi. They take place not only between the ends of the villi and the decidua forming the roof of the placenta, but also wherever decidua and villi come into contact. Hence similar attachments are also formed between the villi and the septa or dissepiments (fg. 484. d /?), which divide its substance into separate lobes. Upon the floor also of the placenta all round the margin, where the decidua turns downwards and inwards to become united with the chorion, and to form the placental margin, the decidua is found for a short distance attached to the bases of the villi. And this arrangement gives to the parts an appearance as if the decidua had been here penetrated by the villi, but one which is actu- ally occasioned by the former having, in the course of growth, become extended around the roots of the latter long after these were first formed. Occasionally also decidual cells may be found upon the surface of villi, con- necting together their extremities, or forming here and there rough irregular belts upon their stems. Termination of the maternal vessels. — No extension of the maternal blood-vessels into the substance of the placenta among or be- tween the villi, can be demonstrated to take place. So far as anatomical evidence goes, the maternal vessels all terminate at once and abruptly upon the inner surface of the decidua. The curling arteries, after passing from the muscular coat of the uterus, obliquely for the most part, through the layer of decidua which forms the roof of the placenta, open directly into the interior of the latter; while the veins commence by equally abrupt openings which * The difficulty of understanding the early steps in the construction of the placenta has arisen from the belief commonly prevalent, that the ovum on first reaching the uterus remains upon the outside of the decidua, and that the villi of the chorion penetrate its substance or enter the uterine glands in order to form the placenta. But there is no actual penetration of the decidua at any period, except that which consists in the entire ovum gaining a situation in the interior of this membrane shortly after its arrival in the uterus. The tips of the villi at a certain stage, as above described, be- come superficially imbedded in the walls of the foetal chamber, which is formed of decidua ; but this is not a penetration of the decidua, as commonly understood, but only a means of fixing the ovum. " conduct through the decidual layer to the venous sinuses in the uterine walls. These venous orifices occupy three situations. The first and most numerous are scattered over the inner side of the general layer of decidua which constitutes the upper boundary of the placenta ; the second form openings upon the sides of the decidual prolongations or dissepi- ments, which separate the lobes from each other ; while the third lead directly into the interrupted channel in the margin, termed the circular sinus. Development of the placenta. — The early steps in the formation of the placenta have been described in the account which has been already given of the development of the deci- dua during gestation (p. 653.). These first steps consist in the formation out of the deci- dua of a perfectly spherical chamber, in the centre of which lies the impregnated ovum. The surface of the ovum is at this time covered everywhere by short club-like villi of equal size. The extremities of these villi are simply in contact with, but are not as yet attached to the walls of the containing cham- ber. Subsequently both the villi and the de- cidua forming the foetal chamber undergo con- siderable metamorphoses. Certain portions of these become intimately united, in order to form the placenta ; while other portions suffer retrogression, and take no part in its construc- tion. The following are the principal features in these metamorphoses. Foetal portion. — The surface of the ovum does not long retain the peculiarity just men- tioned, of being equally covered by villi. Dur- ing the second month at least, if not earlier, those villi on the side furthest from the uterus cease to grow, and in consequence of the increasing expansion of the ovum become more widely scattered over this part of its surface, while those nearest to the uterus rapidly increase in size and extent, so that this portion of the ovum soon exhibits a pro- fuse growth of villous processes, which send out their ramifications in all directions. According to Professor Goodsir, the deve- lopment and growth of the villi proceed from the groups of cells already described as occu- pying their bulbous extremities. These swell- ings on the sides and ends of the villi are their germinal spots, and are the active agents in the formation of these parts. The villus elongates by the addition of cells to its extre- mity, the cells passing off from the germinal spot, and the spot receding on the extremity of the villus, as the latter elongates bj the additions which it receives from it. As the villi increase in size, their strength is gradually augmented by the conversion of the membrane and cells forming their stems and larger branches into a tough white fibrous texture ; while frequently, towards the end of gestation, calcification is observed to begin within the finer villi, and to proceed sometimes to so great an extent that a considerable num- ber of them become filled up and obliterated by solid matter. While these changes are going on in the outer portion of the villi. or 720 UTERUS AND ITS APPENDAGES. that which is derived from the chorion, im- portant modifications occur in the interior structures. Up to a certain period of gesta- tion, the chorion and its villi contain no blood-vessels. According to the author last quoted, blood-vessels first appear in these parts when the allantois reaches and applies itself to a certain portion of the interior surface of the chorion. The umbilical vessels then commu- nicate with the substance of the villi, and be- come continuous with loops in their interior. Those villi in which the blood-vessels do not undergo any further development, as the ovum increases in size, become more widely sepa- rated, and lose their importance in the oeco- nomy. The villi, again, in which vessels form, in connection with the umbilical vessels, in- crease in number, and undergo certain changes in the arrangement of their constituent ele- ments. As the blood-vessels increase in size, the cells diminish in number, but are always found surrounding the terminal loop of ves- sels in the situation of the germinal spot. The injections of Schrceder van der Kolk * show a profusion of capillaries within the villi as early as the third month. And at later periods of gestation, up to the sixth month, I have succeeded without difficulty in display- ing, by the aid of fine injections, such an abundant development of these vessels, as is exhibited in fig. 485, Before the end of ges- tation, however, the greater part or all of these fine capillaries have disappeared, and the vessels within the villi then show only the long tortuous varicose loops which Good- sir has so well described. Such are the principal modifications which normally take place during the development and growth of the foetal portion of the pla- centa. The changes occurring in the maternal portion, or that which is supplied by the de- cidua, are not less remarkable. Maternal portion. — Four principal stages may be observed in the formation of this por- tion of the placenta. The first stage is that in which the decidua constitutes a perfectly spherical chamber *j* surrounding the ovum, but having as yet no structural connection with it (fig. 486.). This is the condition of the ovum in the early part of the first month of gestation. The second stage is marked by the com- mencing attachment of the villi all round to the inner surface of the containing chamber, so that now the ovum becomes fixed, and can no longer be turned out, except by breaking off the villi, or drawing out their ends from the little pits, or anfractuosities, already de- scribed in the walls of the decidua, in which they have become embedded. At this period (latter half of the first month), the decidua forming the walls of this chamber is suffi- ciently firm to admit of dissection, and already there may be traced, upon its inner surface, * Loc. cit. pi. i.fig. 1. f For an account of the formation of the foetal chamber, and of the early steps in the construction of that portion of the placenta which belongs to the decidua, see p. 653. Fig. 486. Decidua at the beginning of gestation, exhibiting the foetal chamber in the first stage of its formation. T/ie ovum, being at this time unattached, has dropped out of it. (After W. Hunter.} orifices communicating with canals in the de- cidua that lead into the uterine sinuses. The maternal blood already flows freely into the foetal chamber, and, after passing everywhere among the villi, is returned into the uterine veins. Thus a temporary placenta is formed, which, as in Pachydermata, Cetacea, &c., en- tirely surrounds the ovum (fig. 487.). The third stage is the most important. It marks the transition from the temporary to the permanent form of the placenta. Coinci- dently with the increased development of the villi on one side of the chorion, and their cor- responding arrest of growth on the opposite surface, there occurs an increase of the space between the decidua and the ovum on one side, and a corresponding decrease of it upon the opposite side. The increase is always on the side next the uterus, where the villi are most abundant, and the decrease upon the opposite surface, where they are fewest. And this change continues progressively, until, upon the bald side of the ovum, the decidua reflexa and the chorion come into so close contact that the interspace is obliterated, and the blood, which formerly flowed freely among the villi, is now no longer admitted to this part of the circumference of the ovum ; while, upon the side which is directed towards the uterus, a large space is left which now takes the form of a meniscus. In order more effec- tually to confine the blood within this limited space, an increased development of decidual cells now takes place, which pass off from the uterine walls, and attach themselves to the chorion all round the circumference of this space, and thus is formed the margin of the permanent placenta. During all this time, the ovum, by its growth, has been gradually rais- ing the decidua above and around it, just as the common integument becomes raised dur- PLACENTA — (FUNCTIONS). Fig. 487. 721 The formation of the foetal chamber more advanced than in Jig. 486. The ovum is still evenly covered by villi, the ends of which, about this time, begin to be attached to the walls of the chamber in which the ovum is contained. o, ovum ; d r, decidua reflexa, forming the foetal chamber; dv, decidua vera; «, uterine walls. ing the formation of a subcutaneous abscess j while in proportion as the base of the chamber becomes extended by the gradual retiring, from the centre, of the line of reflexion of the de- cidua, like waves receding from a central point, so, at the same time, an increasing surface is produced by the expansion of the uterus itself; and the layer of decidua here formed, com- monly termed the decidua serotina, is simply the mucous membrane reproduced to supply the place of that which had been consumed or pushed off in forming the decidua reflexa. The fourth or final stage consists in the partitioning of the permanent placenta into smaller portions or lobes by the extension of the layer of decidua (serotina) which lies op- posite to the developed villi inwards at vari- ous points towards the chorion. In this way are constructed the dissepiments already de- Supp. scribed as bounding the several lobes or co* tyledons. This partitioning of the placenta commences about the fourth month. Thus, during these several stages in the formation of the placenta, two processes may be said to be concurrently carried on which tend in opposite directions — a process of positive enlargement and growth combined with one of relative retrogression or limita- tion. For while the bulk of the placenta is progressively increasing up to the completion of pregnancy, the relative amount of surface of the ovum appropriated to it is, on the other hand, diminished. The entire surface of the chorion being, in the first stages of develop- ment, employed as a placenta ; while in the latter half of gestation, one third of it suffices for that purpose. Function* of the placenta. — By means of 3 A 722 UTERUS AND ITS APPENDAGES. the placenta, the blood of the mother is brought into mediate relation with that of the foetus. Two currents, the one foetal, and the other maternal, are continually flowing into and from this organ, yet in channels so perfectly distinct that no direct commingling of the streams can ever take place. Never- theless, though no passage of the form-ele- ments of the blood can occur, yet through the partition- walls which separate these two currents, all the materials necessary to the growth of the foetus are conveyed by endos- motic processes, and all the changes necessary to the respiration of the foetus, and to the elimination of effete materials, are effected. The mechanism by which these ends are accomplished is of two kinds. The one consisting of means for bringing the two con- stantly flowing streams of blood into juxta- position, the other of instruments for carrying on the nutritive and eliminative processes which are the objects of this conjunction. The foetal blood conveyed by the branches of the two umbilical arteries, is distributed to the villi, whence, after being exposed, in the finer vessels and capillaries which ramify upon their inner surface, to the influence of the maternal blood, it is returned to the funis by the branches which terminate in the single vein. The propelling power by which the blood is moved resides in the heart of the foetus, and the whole of its circulating fluid is thus carried in successive portions through the placenta. The maternal blood, after having its im- petus diminished by the spiral course which the arteries take in passing through the walls of the uterus, as well as through the decidua, is delivered at once into the placenta, where it becomes immediately separated into fine streamlets by the villi which are so closely set as to break up the interior of the organ into countless channels. After flowing every- where among the villi, the blood escapes back into the uterine system * by the venous prir * I can arrive at no other conclusion than that the blood in the interior of the placenta, is as much external to the maternal vascular system as it is while passing through a quill inserted between the divided ends of a vein in a h'ving.animaL Although, irt" this belief, I find myself opposed to the views of Weber, Miiller, J. Reid, Goodsir, and Schroeder van der Kolk, who, with certain differences maintain that the blood is still retained within the maternal system. The views of these and of many other physiologists, who more or less agree with them, are divisible into two classes. According to one view, the uterine vessels either form a network in the substance of the placenta (Weber), or become expanded into an enormous sac, composed of the inner coat of these vessels, which envelopes every- where the surface of the villi (J. Reid), so that the blood after circulating within the placenta is re- turned to the uterus without having been extrava- sated. According to the other view (Goodsir and Schrceder van der Kolk), the decidua throws a close investment over every villus, and forms that outer covering of cells which I have ascribed to the chorion ; so that in this view a lamina of uterine structure still separates the maternal blood from the exterior of the villi. On this and other points relating to the minute fices upon the surface of the decidua, and upon the dissepiments and marginal furrows from which it is conducted, through the deci- dual coat, to the sinuses in the substance of the uterus, and thence is returned to the mother's body by the uterine and spermatic veins. During the flow of these streams through the interior of the placenta, the surface of the villi is constantly bathed by the maternal blood. Nevertheless the blood of the foetus is separated from that of the mother — first, by the walls of its own capillaries ; secondly, by the gelatinous membrane in which these ramify ; and thirdly, by the external non-vas- cular nucleated sheath derived from the cho- rion. With the latter alone, the maternal blood is brought into direct contact. Each of these structures has its distinct office. The use of the external layer of cells {fig. 485. 6) has been happily illustrated by Goodsir. They are to the ovum what the spongioles are to the plant : they supply it with nourishment from the soil in which it is planted. Thus their action is selective, and they transmit to the interior of the villus the materials necessary for foetal growth. These again are taken up by the internal layer of cells {fig. 485. 6), and by them brought into direct contact with the foetal capillaries. By a similar process, the interchanges necessary to respira- tion are effected through the membranous sur- faces which separate the maternal and foetal blood. And these processes, respiratory and nutritive, are continued without intermission from the moment that the two separate cur- rents are established until the final separation of the foetus in the act of birth. Yet, through- out pregnancy, the form of the mechanism by which these changes are effected is continually altering, either in its greater or lesser parts. The greater changes have reference chiefly to mechanical, and the lesser to vital necessities. The changes in form exhibit a beautiful series of. adaptations in the. capacity and strength of the placenta to the increasing amount and force of the maternal current. The original plan of the placenta, that of an interspace be- tween two spheres (a lesser one contained within a greater) filled by maternal blood, could not be long preserved with the materials out of which the temporary organ is con- structed. For as the ovum grows, the deci- dua reflexa, which alone confines the blood structure and composition of the placenta, consult Von Baer, Untersuchungen tiber die GefUssver- bindung zwischen Mutter und Frucht in den Sati- gethieren. 1828. Ritgen, Beitrage zur Aufhellung der Verbindung der Menschlichen Frucht mit dem Fruchthalter. 1835. Sharpey, in Muller's Physi- ology by Baly. 1837 and 1848. Eschricht, De orga- nis quae respirationi et nutritioni foetus mammalium inserviunt. 1837. E. H Weber, in Hildebrandt's Anatomie, b. iv., and in Wagner, Elements of Phy- siology. 1841. J Reid, Edinb. Med. and Surg. Journ., No. 146. J. Dalrymple, Medico-Chirurgical Trans., vol. xxv. 1842. Gondsir, J. and H., Anatom. and Pathol. Observs. 1845. Schrceder van der Kolk, Waarnemingen over-het Maaksel van de Mensche- lijke Placenta, en over haren Bloods- omloop. 1851. PLACENTA — (FUNCTIONS). that flows around it, becomes thinner, and finally gives way by extension. But long be- fore this stage arrives, the whole of this por- tion is shut out from the maternal circulation, and the subsequent metamorphoses are di- rected to the strengthening of the more limited space which remains. It is on this account that the strong border of decidua is formed around the margin of the now restricted area. The base of the placenta now consists of the tough and resisting chorion ; while that por- tion alone of the decidua which is strength- ened externally by the uterine walls is retained to form the opposite boundary. Ultimately, as the current of maternal blood flows with increasing force into the placenta in propor- tion to the growth of the latter, this becomes subdivided by the decidual septa, which ap- portion the entire organ into separate placen- tulae, and thus the larger supplies necessary to the increasing exigencies of the foetus are disposed of without danger of rupture to any portion of the organ. The changes in the more minute structures which belong to the foetus are not less inter- esting. The profuse development of fine capillaries within the fcetal tufts, which is so conspicuous from the third to the sixth month, is connected not only with the functions of respiration and nutrition of the foetus, but also with the growth of the villi themselves. But when the period of viability of the foetus has arrived, the proportionate amount of capillary vessels within the villi becomes greatly re- duced, until finally only the original stems of the vessels are left. And this relative reduc- tion of the channels through which the foetal blood flows, becomes more marked, until, as the time of birth approaches, many of the villi become more or less obliterated, and cease to admit blood, often in consequence of that calca- reous degeneration which, from the frequency of its occurrence, may be regarded rather as a normal process significant of natural decay than as an evidence of any morbid or preter- natural change. The series of metamorphoses is closed by the degeneration of the materials which bind the placenta, and consequently the foetus, to the uterus. The layer of decidua forming the connecting medium between the uterus and the foetal structures, in common with the rest of this membrane, suffers slow disintegration, and its component cells are converted into molecular fat. And now the strength of the adhesion being gradually diminished, it only remains for the contractile power of the ute- rus to be evoked in order to accomplish the separation together of the foetus and placenta, like ripe fruit detached from the parent bough. The illustrations of this article marked, " ad na- turam," are from original drawings and preparations in the possession of the author. For the rest of the figures the authorities are given. The usual signs are employed : for an inch " ; for a line "'; and for the amplification x. The following tabulated arrangement of the prin- cipal contents will facilitate reference to the several 723 subjects, as well as to the books quoted in the foot notes of this article. UTEKUS AND ITS APPENDAGES. OVARY. Normal anatomy. form, 547. dimensions and weight, 547. position and connections, 548. Component parts : 1. protecting parts or tunics, 548. peritoneum, tunica albuginea, 548. 2. parenchyma or stroma, 549. 3. Graafian vesicles, 550. 4. blood-vessels and nerves, 552. Functions of the Ovary. the developmental changes in the ovicapsules, and the process of emission of ova, 552. 1st stage, origin of the ovicapsules, 554. 2nd stage, growth, maturation, and prepara- tion for dehiscence, 555. 3rd stage, rupture or dehiscence, and escape of ova, 558. 4th stage, decline and obliteration of the ovi- capsules, 561. A. without impregnation, 561. B. after impregnation, 563. spontaneity of the emission of ova, 566. nature of the corpus luteum, 564. 569. classified arrangement of all the conditions which the Graanan follicle exhibits during evolution and involution, 570. summary of the conclusions which these conditions afford with reference to questions in obstetric and forensic medicine, 571. Development and Involution of the Ovary. the origin of the ovary, and the alterations which it undergoes at different periods of life, 571. Abnormal Anatomy of the Ovary. effects of extirpating the ovary, 573. deficiency and arrest of development, 573. atrophy and hypertrophy, 573. displacement, hernia, 573. diseases of the tunics, inflammation, 574. ulceration, rupture, 574. hypertrophy, calcification, 574. diseases of the proper tissues, hyperaemia, 576. inflammation, 576. suppuration, 577. simple, multiple, multilocular, and proliferous cysts, 578. the contents of ovarian cysts, 582. fluid contents of cysts, 582. quantity and rate of effusion, 582. composition of the fluids contained in ovarian cysts, 583. hydatids, 584. solid contents of ovarian cysts ; sebaceous and sudoriparous glands ; fat; hair; teeth; true bone, 584. origin of the solid contents of cysts, 586. foetus contained in the ovary (?); the question of ovarian gestation considered, 586. examples of supposed ovarian gestation, 587. solid enlargements of the ovary, 591. cartilaginous and ossific formations, 591. cancer, colloid or alveolar ; medullary and scirrhous, 591. scrofulous tubercles, 593. THE PAROVARIUM. Structure and development, 593. Abnormal states, 597. THE FALLOPIAN TUBE OR OVIDUCT. Normal Anatomy. form ; dimensions, 597. situation and connections, 598. separate parts and divisions, 599. internal orifice, 599. uterine portion of the tube, 600. canal, 600. external orifice, 600. pavilion or infundibulum, 601. fimbriae, 601. tubo-ovarian ligament, 602. structure of the coats or tunics, 603. blood-vessels and nerves, 604. Functions of the Fallopian Tube. reception and transmission of ova and spermatic fluid, 605. first steps in the process of impregnation, 608. the changes which the ovum undergoes in the tube, 609. Development of the Fallopian Tube. formation of the oviduct out of the duct of MUller, 613. SA 2 724- UTERUS AND ITS APPENDAGES. FALLOPIAN TUBE (.continued). Abnormal Anatomy of the Fallnpian Tube. defect and imperfect development, 614. peculiarities of construction, 615. displacements, 616. obliteration of the canal, 617. hyperaemia ; inflammation 617. colle -lions of fluid within the tube ; blood ; serum; pus, 617. cysts, 620. fibrous tumours, 620. tubercle ; cancer, 620. rupture of the tube walls, 620. Fallopian tube gestation ; various forms, 620. UTERUS. Normal Anatomy. situation and position, 623. form, 624. dimensions and weight, 624, regional divisions ; fundus ; body ; cervix, 624. external surface, 626. internal surface, and cavities of the body and cer- vix, 6.'6. structure and arrangement of the tissues composing the body of the uterus, 630. peritoneal coat, 631. middle or muscular coat ; composition; course of the muscular fibres, 63i . mucous or deciduous coat ; composition, 635, utricular glands or follicles, 636. structure and arrangement of the tissues composing the cervix uteri, 638. muscular coat, 638. mucous coat ; epithelium, 638. papillae, 639. mucous follicles, 640. blood-vessels of the uterus, 640. lymphatics, 641. nerves, 6)1 . Development and Metamorphoses of the Uterus at different periods of Life. a. origin of the uterus, and its condition during foetal life, 642. b. the uterus from the time of birth to puberty, 643. c. the uterus during menstrual life, 644. d. the uterus during gestation ; the gravid or fully developed uterus, 644. sfie »nd weight, 64*. alterations rtuiiut; gestation in the form of the body and cervix uteri, 645. position, actual and relative, of the uterus during gestition, 647. alterations in the special coats and tissues, 649. the peritoneum, 649. the muscular coat, 649. the blood-vessels, 651. nerves •', the question of enlargement of the uterine nerves during pregnancy, 651 . mucous or lining membrane of the uterus; development into the decidua ; decidua vera and reflexa, 652. histology of the decidua, 657. e. the uterus after parturition, 658. the process of involution of the gravid uterus, 659. changes in dimensions and weight, 658. metamorphosis and restoration of the compo- nent tissues, 659. f. the uterus after the menstrual epoch ; senile atrophy or involution of the uterus in advanced life. 661. Functions of the Uterus. a. the office of the uterus in menstruation, 662. periods of duration and recurrence of this function, 6(j2. quantity, 663. nature of the catamenial discharge, 663. composition of the menstrual fluid : analysis, 663. microscopic examination, 663. the unmixed menstrual fluid ; analysis, 664. source of the menstrual flux, 665. the means by which the blood escapes during healthy menstruation, 661. the purpose of menstruation, 666. the relation of this function to the maturation and emission of ova examined, 667. the purpose of the flux, 670. b. the office of tne uterus In insemination, 671. c. the office < f the uterus in gestation, 672. d. the office of the uterus in parturition, 672. general sketch of ihe labour process, 672. the peristaltic action of the uterus, and its cause, 673. the ryihmic action of the uterus, and its cause, 674. influence of the different nervous centres upon the uterus in pai turition, (>75. the exciting cause of labour, 767. UTERUS (continued)' Abnormal Anatomy of the Uterus. defective development, 678. 1st class, congenital de'ect?, 678. the various abnormal forms of the uterus, arising from imperfect coalescence of the primitive uterine halves (com- monly termed double uterus), ar- ranged in lour groups: group I. uterus bipartitus, 678. group II. uterus unicornis, 679. group III. uterus bicornis, 679. group IV. uterus bilocularis, 680. 2nd class, incomplete development at the time of puberty. the pre-pubertal uterus, 681. anomalies of form of the uterus, 682. antiflexion, 682. retroflexion, 683. lateral inflexion, 683. anomalies of position of the uterus, 683. obliquity, 683. anti- and retro-version, 683. hernia of the uterus, 684. prolapsus, 684. elevation, 684. inversion, 6*-!. anomalies of size of the uterus, 686. atrophy, 68*i. hypei trophy, 687. pathological conditions of the separate tissues of the uterus, 687. 1. pathological conditions of the peritoneal coat; acute and chronic metro-peritonitis, 687. 2. pathological conditions of the subperitoneal fibrous rissue; peri-metritis, 688. 3. pathologiial conditions of the muscular coat, 689. diminished and increased consistence, 689. parenchymatous inflammation : metritis, 689. fibroid, or fibrous tumour of the uterus ; interstitial, sub-peritoneal, and sub- mucous fibroid; fibrous and muscular " polypi," 6n9. 4. pathological conditions of the mucous coat, 6'J.'. simple hypertrophy; dysmenorrhoealmem- brane, 692. hypertrophy of the follicular structures of the uterine mucous membrane ; follicu- lar " polypi ; " mucous " polypi ; " cysts, 692. hypertrophy of the filiform papillae of the cervix (pseudo-ulcer), 693 simple inflammatory hypertrophy, with extroversion of the "cervical mucous membrane (pseudo- ulcer;, 693. catarrhal inflammation of the mucous coat of the uterus ; endometritis; leucorrhcea, 69*. ulceration of the mucous coat ; erosion, abrasion, and excoriation, 694. distensions of the uterine cavity, hydrometra, 697. haematometra, 697. physometra ; tympanites uteri, 698. hydatids, 698. narrowing and obliteration of the uterine cavity, atresia of the os uteri, cervical canal, and cavity of the uterine body, 698. pathological conditions involving several of the utori n> tissues, cancer, 699. cancroid ; epithelial cancer ; cauliflower excre- scence, 700. corroding ulcer, 700. tubercle, 701. solutions of continuity; rupture; perforation, 701. pathological conditions of the uterus after par- turition, irregular contraction ; hour glass contraction (arre ted peristaltic action), 702. incomplete and retarded involution, 702. puerperal inflammation, endo-metritis, 702. metro-phlebitis, 703. metro-peritonitis, 703. blood dyscrases, 704. LIGAMENTS OF THE UTERUS. Normal Anatomy. the l>road ligament, 705. the utero-sacr.il ligaments, 705. the utero-vesical ligaments, 705. the round or sub-pubic ligaments, 705. VAGINA. Normal Anatomy. dimensions, 706. external surface, 706. UTERUS AND ITS APPENDAGES. 725 VAGINA (continued). EXTERNAL ORGANS (continued). composition, 706. blood-vessels and nerves of the external organs, internal surface, 706. 713. arteries; veins; lymphatic?; nerves, 707. Abnormal Anatomy. uses of the vaginaj 707. lai>ia, 714. Abnormal Anatomy. clitoris, 714. anomalies of form and size, 707. nymphae and vestibule, 714. displacements, 707. hymen and ostium vaginae, 715. solutions of continuity, 707. inflammation, "07. ' PLACENTA. epithelial desq> amation, 707. Normal Anatomy. serous and sanguineous infiltration, 707. form, 715. abscess : ulceration ; gangrene, 708. dimensions and weight, 715. cysts and tumours, 708. foetal surface ; amnion ; chorion ; foetal blood- cancer, 7( 8. vessels, 715. uterine surface, 716. EXTERNAL ORGANS OF GENERATION. circumference, 716. Normal Anatomy. substance, 717. the mons veneris, 70S. tufts and villi, 717. labia, 70*. terminaiions of the foetal vessels, 718. clitoris, 709. decidua, 718. nymphae, 710. terminations of the maternal vessels, 719. vestibule, 710. Development of the Placenta. vaginal orifice and hymen, 710. of the Icetal portion, 719. origin, varieties, and signification of the hy- of the maternal portion, 720. men, 7 1 0. Functions of tht placenta, 721 . sebaceous and muciparous glands and follicles of the vulva; vulvo-vaginal gland, 711. / 4~tj,,lv BV,--- \ bulb of the vagina; pars intermedia; constrictor rre') vagina?, 712. ANALYTICAL INDEX TO THE SUPPLEMENTARY VOLUME. ANALYTICAL INDEX SUPPLEMENTARY VOLUME. Ovum (in Animal Anatomy and Physiology), 1. (See also (Jencratioii). I. of the ovum in general as related to the sexual process of generation, 3. definition, 3. ovulation, 3. the chorion, 3. the spermatic substance or sperm, 3. the embryo-cell, 4. development, or embryo-genesis, 4. structural distinctive characters of an ovum, 5. II. of the non-sexual mode of peneration, ft. 1. of the process of reproduction iu protozoa, or animals in which the sexual distinction has not yet been discovered, 6. Gregarina?, 7. 2. of the possibility of primary, direct, or non- parental production of animals, or of so-called spontaneous and equivocal generation, 9. Entozoa, 11. 3. production of dissimilar individuals among sexual animals by a non-sexual process : so- called alternate generations, 12. embryological development, 12. metamorphoses, 12. metagenesis, 13. 38. larva, 13. Echinodermata, 14, Polypina, 16. Acalephae, 20. Mollusca, 22. Salpidae, 23. Entozoa, 24. Cystic Entozoa, 25. free tapeworms, 27. Trematoda, 29. Annelida, 32. Insecta: Aphides. 33. general remarks on alternate generations, 13. 34. the " nurse" of Steenstrup, 37. parthenogenesis, 37. additional remarks, 4". of the ovum previous to the commencement of foetal development, 43. I. anatomical structure, chemical composition, origin and formation, of the ovum in Vertebrate Animals. 43. $ 1. preliminary and general comparison of the ova of animals, 43. general facts ascertained in regard to the ova of animals, 45 division of ova of animals into groups, 46. first group, 4f,. second group, 46. tliird group, 47. § 2. further comparison of the ova of an;mals in general, as respects their size, number, form, and the relation of their parts, 48. size of ova, 48. number of ova, 49. external form and relation of the parts, 50. in Birds, 50. in oviparous scaly Reptiles, 50. in oviparous cartilaginous Fishes, 50. in the Frog, 51. in Newts, 51. §3. of the ovary in general as the formative organ for the ova of animals, 52. a. relations of the form of the ovaries to the discharge of ova, 54. b. structure of the ovaries themselves, as related to the production of ovula, 50. Sup p. Ovum, anatomical structure, &c. — continued. § 4. more detailed description of the ovum of birds as the type of the first group, 60. quantity of matter, composition, &c. 60. structure of the external parts of the egg, 63. the chalazae (grandines). 64. formation of the external or accessory parts of the bird's egg, 65. ovarian ovum of birds ; ovulum ; yolk and its contents, 68. microscopic structure of the ovum, 71. early condition and first formation of the ovarian ovum in birds, 74. morphology of the bird's egg, as ascer- tained from its first origin and develop- ment, 75. § 5. more detailed description of ova belonging to the second group, or with small granular yolk and complete segmentation, 80. ovum of mammalia and of the human species, [81]. uniformity in size, &c. [81]. Graafian follicles, [81]. tunica or membrana granulosa, [R2]. external tunic, or zona pellucida, [82]. chorion, [84]. contents of the ovum, or parts within the zona, [86]. the yolk-mass, [86]. the germinal vesicle, [87]. the macula or nucleus, [*7]. manner in which the ova of mammalia may be procured, [88]. origin and formation ot the mammiferous ovum, [89]. formation of the ovules, [89], origin of the Graafian follicles, [89]. formatioD of the cumulus, [9(>]. similarity of the structure of the ovum throughout the families of the class Mammalia, [90]. except in the Monotremata, [90]. ova of the Ornithorhynchus, [91 J. ova of Echidna hystrfx, [91]. third group of the ova of "Vertebrate Animals, [91]. Amphibia — Batrachi.i, [91]. structure of the ripe ovarian ovum in Amphibia ['.'2]« germinal vesicle [f'3J. yolk-substance. [93]. formation of the ovum, and changes in its progress, [94]. Osseous Fishes. [98]. II. Invertebrate Animals, [104]. l;irge-\oked ova with partial cleavage, [105]. Cephalopoda, [105]. Gasteropoda, [106]. Acephal i, [10*], Arthropoda. [110]. In.-ecta, [110]. " Arachnida, [114]. Crustacea, [115]. Annulata, [1 17]. Kotifera, [118]. Turbellaria, [119]. Entozoa, [120]. Nematoidea, [120]. Trematoda. [Iv4]. Cestoidea, [I '24]. Echinodermata, [125]. 13 B 730 ANALYTICAL INDEX Ovum. Invertebrate Animals — continued. Polypina, [126]. Acalephae, [129]. Protozoa, [129]. Porifera, [129]. Recapitulation and conclusion, [130]. 1. definition of the ovum, as related to its own structure, and fts history in connection with the reproduction of the species, [130]. 2. recapitulation of the most general facts ascer- tained by the comparison of the ova of different animals, [132]. 3. morphology of the ovum : homology of its parts, and relation of the ovum to other organic structures, [134]. 4. phenomena attendant on maturation of the ovum, and its discharge from the ovary, [186]. 5. relation of the ovum to fecundation by the male sperm, [136]. 6. immediate effects of fecundation on the ovum : segmentation, and first changes of the ovum related to the commencement of embryonic de- velopment, [138]. chemical composition rf the ova of animals, [141]. the albumen or white, [141], vitelline, [141]. hine, [141], ichthine, ichthidine, [14 1]. ichthuline, [141J. Pancreas, 81 . I. Human Anatomy, 81. situation, 81. relations, 81. shape, 82. right extremity or head, 83. left extremity, 83. upper border", 83. lower border, 83. anterior surface, 83. posterior surface, 83. size and weight, 83. general appearance, 84. internal structure, 84. duct of the pancreas, 84. vessels, 86. arteries, 86. lymphatic vessels 86. nerves, 86. II. Microscopic Anatomy, 86. gland substance, 86. M. the basement or limitary membrane, 87. /3. epithelium, 88. y. occasional appearance of a central cavity in each follicle, the epithelium lining it in a single columnal-looking layer, and leaving a central space unoccupied, 89. duct, 89. capillaries, 90. III. Comparative Anatomy, 90. Invertebrata, 90. Gasteropoda, 90. Cephalopoda, 90. Vertebrata — Fishes, 91. pyloric appendages, 91. Reptilia, 94. Batrachia, 94. Ophidian Reptiles, 95. Saurian Reptilia, 95. Chelonia, 95. Aves, 96. table of pancreatic ducts in several orders of birds, 97. Mammalia, 98. IV. Physiology, 99. results of analyses of pancreatic secretion, 102. function of the pancreatic fluid, 105. V. Morbid Anatomy, «. quantitatively perverted nutrition, 108. hypertrophy, 108. atrophy, 108. induration, 109. softening, 1C9. b. inflammation, !09. r. haemorrhage, 1!0. d, structural changes, 110. 1. non-ma:ignant : cartilaginous transforma tion, 110. steatomatous concretions, 110. cystic tumours ; hydMtids, 110 fatty degeneration,"! 11. 2. malignant, 111. scirrhus and carcinoma, 111. fungo-haematoid disease, 1 12. e» calculous concrftionsin the pancreatic duct, 112. occurrence of fitly stools in connection with pancreatic disease, \\'L Pelvis, 114. innominate bone, 114. its office, 114. superior border, 114. anterior border, 111. inferior border, 115. Pelvis, innominate bone — continued, posterior border, 115. external or femoral surface, 115. the acetabulum or cotyloid cavity, 116. descending ramus or body of the ischium, 116. horizontal ramus or body of the pubis, 116. ascending ramus of the ischium, 116. descending ramus of the pubis, 116. obturator or thyroid foramen, 116. sub-pubic or obturator groove, 116. internal or pelvic surface, 117. iliac tuberosity, 117. sacral or auricular surface, 117. internal iliac fossa. 117. ilio-pectineal line, 117. internal structure of the innominate bone, 117. sacrum, 1 18. its office, 118. base, 118. apex, 118. anterior or pelvic surface, 118. posterior surface, 11H. lateral surfaces, 119. internal structure of the sacrum, 119. coccyx, 120. development of the pelvis, 120. innominate bone, 120. sacrum, 120. coccyx, 121. pelvic articulations and ligaments, 121. lumbo-pelvic articulations, 121. proper or intra-pelvic articulations, 121. sacro-coccygeal joint, 122. motions of the joint, 122. sacro-iliac joints, 122. cartilages lining these articulations, 122. inter-osseous ligaments, 123. interosseous sacro-iliac ligament, 123. anterior ligament, 123- posterior sacro-iliac ligaments, 123. the deep and superficial layers of fibres, 123. ilio-lumbar ligament, 124. great sacro-sciatic ligament (ligamentum pelvis posticum magnus), 124. lesser or internal sacro-sciatic ligament (ligamentum pelvis posticum parvum), 124. movements of the sacro-iliac joint, 125. pubic symphysis, 125. anterior pubic ligament, 125. posterior pubic ligament, 125. superior pubic ligament, 125. inferior or sub-pubic ligament, 126. movements of the pubic symphysis, 126. obturator or thyroid membrane, 126. general appearance of the articulated pelvis, 126. its interior aspect, 126. lateral aspects, 126. posterior aspect, 126. superior aspect, 126. false pelvis, 127. brim of the pelvis, 127. cavity of the true pelvis, 127. inferior aspect, 127. differences of the pelvis in the sexes, 128. measurements of the pelvis, 129. at the brim, 129. in the cavity, 129. at the inferior strait, 129. table of measurements of the pelvis, 130. inclination of the pelvis, 131. angles of the anterior and posterior pelvic walls with the transverse vertical plane, 133. ilio-isehial angle, 134. angle of ischio-pubic arch, 134. axes of the pelvis, 134. axis of the brim, 135. of the inferior outlet, 135. general development of the pelvis, 135. the pelvis of infants, 136. in advanced adult age, 137. muscular attachments of the pelvis, 137. 1. muscles acting on the trunk and spine, 137. posterior spinal group, 137. abdominal group, 137. 2. muscles acting on the leg, 137. flexor group, 137. extensor group, 137. adductor group, 137. abductor group, 137. rotator group, 137. 3. muscles acting on the perineum and genitals, 138, posterior perinea! group, 138. anterior perineal group, 138. fascial attachments, 138. lumbar fascia, 138. abdominal fascia;, 138 crural fascia or fascia lata, 138. pelvic fascia, 138 pciinoul fascia, 138. crura of the penis or of the clitoris, 138. TO THE SUPPLEMENTARY VOLUME. 731 Pelvis — continued. mechanics of the human pelvis, 138. in regard to parturition, l-lfi. comparative anatomy of the pelvis, 148. pelvis of Negro, 148, 149. pelvis of the Bushman, 149. Tahitian, 150. Australian. 150. Javanese, 150. measurements of pelves of various races: — 1. the oval form, 150. 2. the round form, 150. 3. the square or four-sided form, 150. 4. the cuneiform or oblong form, 150. pelves of the Simize, 151. of the Carnivora, 154. Fhocae, 155. Pachydermata, 155. Kuminantia, 157. Rodentia, 158. Marsupialia, 159. Monotrrm.ita, 161. Edentata, 161. Insectivora, 164. Cetacea. 165. Birds, 165. Reptiles, 170. Fishes, 172. table of comparative pelvic angles, 174. serial homologies of the pelvic bones and liga- ments, 174. Pelvis (abnormal anatomy of the}, 178. pelvic deformities and obstructions, 178. 1. normal irregularities, 178. equable deviations, 178. pelvis equabiliter justo major, 178. pelvis equabiliter justo minor, 178. cause, 179. irregularities from imperfect development — infantile pelvis, 179. masculine pelvis, 180. irregularities of the pel»i-vertebral angle, 181. 2. distortions, 181. distortions affecting the brim only or princi- pally. 181. distortions affecting the cavity only or princi- pally, 1-2. vertical flatness of the sacrum, 182. in ward projection of the sciatic spines, 182. distortions affecting the outlet only or princi- pally, 183. contraction of the transverse diameter, 183. special cause of this deformity. 183. contraction of the antero-posterior dia- meter, 183. distortions affecting the whole pelvis, 185. ovate, ellip ical, or reniform pelvis, 185. ilia and ischia, 185. symphysis of the pubis, 185. diameter, 185. sacro-vertebral angle, 18".. inclination of the superior plane, 185. cordiform or angular pelvis, 187. sacral promontorv, 187. ilia a,id ischia, 187. pubic symptiysis, 187. angles of trie superior and inferior pubic planes, 187. diameters, 187. causes of the foregoing pelvic distortions, 189. rickets, 189. mollities ossium or malacosteon adulto- rum, 190. mechanism of the preceding pelvic distortions, 195. influence of the centre of gravity of the trunk, 195. the line of pressure, 196. influence of continued posture, 196. lying upon the back, 196. lying upon the side, 197. tendency of the sitting posture, 197. degree of obstruction, 199. the pelvis oblique ovata, or obliquely con- tracted pelvis, 200. can^e. of the obliquely deformed pelvis, 203. mechanism of this deformity, 2n4. obstructions caused by osteu-sarcoma- tous tumours, 20*>. obstructions from fibrous tumours at- tached to the pelvic ligaments, 206. effects of carcinomatous growth, 206. pathology of the pelvic joints, 206. ankylosis, 207. coalescence of the bones composing the sa- cro-lumbar articulatiot s, 4i07. ossification of the satro-iliac joint, 207. ossification of the sacro sciatic ligaments, 207. separation of the bones at their articular surfaces, 207. Pelvis (abnormal anatomy of the) —continued. other congenital abnormalities, 208. siren formation of pelvis, 208. influence of hip-joint disease upon the pelvis, 208. fractures and dislocations of the pelvic bones, 208. fracture of the sacrum, 2(8. coccyx, 209. innominate bone, 209. dislocation of the sacro-iliac or pubic joints, 209. displacement, 209. diagnosis, 210. Reproduction, Vegetable (Vegetable Ovum), 211. Part I. Algae, Fungi, and Lichens, 212. reproduction by means of zoospores, 212. under the most simple conditions, 212. confervoid Algae, 213. the frond, 213. Ulvacea?,214. zoospores developed in an organ specia'Iy des- tined to the purpose, 214. zoosporous reproduction in the olive-coloured Alga?, 214. fructification in the Fucaceae, 215. the ant herozoids of the Fucaceae compared with the z iospores of the other olive-coloured Algae, 216. zoosporous reproduction in the family of Vau- cheriaceae, 216. and in the Saprolegnia ferox, 217. Pilobolus, 218. zoosporous reproduction in some fungi, 218. reproduction by conjugation, 218. in Desmidi*, 218. in Zygnemaceae, 219. in Palmoglea macrococca, 220. condition uiider which conjugation takes place among the Algae, 220. plants obtained l>y the germination of the zoospores of Saprolegnia, producing repro- ductive organs of an entirely different cha- racter, *20. reproductive organs of the red Algae or Floridae, 221 . the first form — a poly spore, 221. the second form — a tetraspore, 221. the third form — the antheridium, 221. reproductive organs of the Charareae, 222, the antheridium of Chara, 222. summary, 222. of the two kinds of zoospores, 223. of zoosporoid bodies, 223. of germs whose development is dependent on the combination of two organs, the repro- ductive functions of which are complemen- tary each to each, 223. Fungi and Lichens, 223. formation and development of the germ in fungi, 224. basidiosporous fungi, 2'24. receptacle of Geaster fimbriatus, 225. the theca or ascus of fungi, 225. the ascophorous Fungi represented by Uredineae, 226. Discomycetes and Pyrenomycetes, 226. researches of MM. Tulasne. 227. formation and development of the germ iu Li- chens, 228. the thallus, 229. the hypothallus, 229. the receptacles within or upon which the spores or spore-like organs are pro. duced, 229. force with which the spores are dis- charged from the thecae, 230. antheridia of lichens, 230. pycnidis, 230. summary" 231. Part II. Higher Cryptogamia and Phanerogamia, 232. vegetative system among the lower Hepatica?, 232. first period — from the germination of the spore, 233. developmpnt of the antheridia, 233. development of the archegoi ia, 233. second period — fructification of the arche- gonia. 234. changes preparatory to the development of the spores, 234. development of the spores, 234. vegetative system in Jungermannia? frondosa?, 235. first period — germination of the spores, 235. antheridia, 235. archegonia, 235. second period — development of the embryo, 236. changes preparatory to the development of the spores, 236. Mosses, 237. first period — germinstl.n of the spores, 235. ' development of the antheridia and arche- gonia, 238. in the genus Phascum, 238. development of the fruit '238. of the spores, 239. SB 2 732 ANALYTICAL INDEX Reproduction, Vegetable {VegelaUe Ovuni)— continued. Ferns, 239. first period — germination of the spore, 239. antheridia, 239. archegonia, 240. origin of each archegonium, 240. the embryo, 241. sporangia and spores, 2H. Equisetacese, 241. first period — germination of the spore, 241. antheridium, 241. archegonium, 242. spores and sporangia, 242. Lycopodiaceae, 243. commencement of the development of the prothal- lium, 243. archegonia. 243. embryo, 243. sporangia and spores, 243. Rhizocarpeae, 245. macrosppre of Pilularia, 245. prothallium, 245. embryo, 245. sporangia and spores, 246. Phanerogamia, 246. Phanerogamia gymnosperrnia, 246. Phanerogamia angiospermia, 248. Hippuris vulgaris, 249. Orchis morio, 250. the anther and the pollen-cell, 251. review of the analogies which present themselves in the history of the development of the repro- ductive organs of the higher Cryptogamia and of the Phanerogamia, 252. 1. analogies existing between the ovule, the anther, and the sporangium, 252. 2. analogy between the embryo-sac, the pollen- cell, and the parent cell of four spores, 252. origin and development of germ-cells in special organs destined for their reception, which are capable of transformation into rudiments of new plants, without the concurrence of two organs of opposite functions, 253. Appendix — On the relations which exist between the animal and vegetable kingdoms, as regards the func- tion of reproduction, 256. Respiration, Organs of. — I. Human and Mammalian, 268. lungs, 258. in man, 258. apices of the lungs, 258. trachea, 258. structural anatomy of the trachea, 259 tracheal mucous membrane, 259. cilia, 260. tracheal glands, 260. fibrous structures, 261. tracheal cartilaginous rings, 2G1. tracheal muscles, 262. arteries of the trachea, 262. bronchi, 2(i2. the bronchi divide on no constant or regu- lar plan, 264. ultimate pulmonary tissue — lobules — historical bibliography, 264. minute anatomy of the lobule, 266. ultimate air-cells of the lungs, — Vesiculae, s. cellulae ae'reae, s. Malpighianae ; alveoli pul- m on urn of Rossignol, 26S. minute structure of the air-cells of the lungs, 270. the epithelium of the air-passages and cells. 270. the elastic tissue of the air-cells of the lungs, 272. vascular system of the lungs, 272. pulmonary artery, 273. veins, 274. bronchial system of vessels, 275. superior artery, 275. inferior artery, 275. bronchial veins, 275. anastomoses between the bronchial and pul- monary systems of vessels, 275. II Comparative Anatomy, 276. respiratory organs of Birds, 276. Reptiles, 278. temporary branchiae of Amphibia, 278. temporary external gills, 279. external temporary gills of the Salmandrida? 279. internal temporary branchiae of Amphibia, 280. sir-bladder of Fishes, 281. lungs in Batrachia, 282. respiratory organs of Fishes, 2H6. mucous membrane of the branchia?, 287. vascular system of the branchia?, 2*7. minute circulation of the branchiae, 288. cartilage, or supporting system of the branchiae, 289. Respiration, Organs of — continued. III. Morbid Anatomy of the lungs and air-passages, 291. inflamma'ion of the bronchi : — a. acute bronchitis, 292. b. chronic bronchitis, 292. c. plastic bronchitis, 292. collapse of the lungs, 292. asthma and hooping-cough, 292. dilatation of the bronchi : uniform dilatation, 292. saccular dilatation, 292. bronchitic collapse of the lungs, 292. of mucous membrane of the bronchi, 292. superficial suppuration, 292. pathological conditions of the broncho-pulmonary mucous membrane, 293. plastic or exudative bronchitis, 293. bronchial croup, 293. asthmatic affections, 293. forms recognised by English pathologists, 293. inflammation of the vesicular tissue, i93. engorgement, 293. hepatisation, 293. grey hepatisation, 293. gangrene, 293. cancer of the lung, 293. phthisis, 293. seat of pulmonary tubercle, 293. nature of tuberculous matter, 293. mechanism of emphysema, 293. Ruminantia, an order of Mammalian quadrupeds, 506. essential characters of the order, 506. and of the sub-orders — Camelida?, 5<>6. Cervidae, 508. Antelopidas, 508. CEgoscerida?, 508. Bovidae, 508. Osteology, 508. bones of the cranium, 5Ci). occipital bone, 509. parietal bone, 509. frontal bones, 509. sphenoid, 510. temporal bone, 511. bones of the face, 512. nasals, 512. intermaxillaries, 512. maxillaries, 513. lachrymals, 513. palatines, 513. vomer and ossa spongiosa seu turbinata, 515. interior maxilla or jaw-bone proper, 516. cranial peculiarities, 516. horns, 516. vertebral column and bones of the trunk, 519. atlas in Camels, 520. axis or deritata, 520. dorsal vertebrae, 520. ribs, 520. pelvic bones, 521. bones of the anterior extremity, 521. scapula, 5'21. humerus,521. bones of the forearm, 521. carpal bones, 522. metacarpals, 522. phalanges of the cloven foot, 522. bones of the posterior extremity, 522. femur, 523. patella, 523. tibia, 523. bones of the tarsus, 523. metatarsals, 523. Myology of Ruminants, 523. panniculus carnosus, 523. musculus cutaneus faciei, 524. m. cutan. humeri, 524. m. cutan. maximus, seu abdominis, 5'24. other muscles of the same category, 524. muscles of the head and trunk, 52). trapezius, 524. broad muscle represented in man by the splenius capit-s and splenius cervicis, 525. trachelo-mastoideu«, 525. great complexus .and diga-tricus colli, 525. transversalis cerviris, 525. scaleni muscles, 525. longus colli and reed, 526. sterno-mastoideus or maxillaris, 526. rectus capitis anticus major, 526. hyoid apparatus, 526. muscles proper to hyoid chain of bones. 527. sterno-hyoids and sterno-thyroids, 527. cmo-hyoid, muscle analogous to, 527. stylo-hyoid, 527. ceratoido-lateralis, 527. maslo-stylo:d, 527. mylo-hyoid, 527. genio hyoids, 527. muscles connected with the hyoid ap- paratus of the Giraffe, 527. TO THE SUPPLEMENTARY VOLUME. 733 JSwninantia — continued. muscles of the shoulder and fore-limb, 528. levator angulis scapulae, 528. rhomboideus major and minor, 528. serratus magnus or major, 528. serratus minor, 528. latissimus dorsi, 528. pectoralis major, 528. ambibrachialis communis, 529. abductor longus brachii, or abd.brach. supe- rior, 529. supra-spinatus and infra-spinatus, 529. teres major, externus, minor, and internus, 5211. coraco-brachialis, 529. biceps brachii, coraco-radialis, or flexor cubiti longus, 529. brachialis internus, or flexor cubiti longus, 529. extensor cubiti, 529. extensor brevis, 529. brachialis externus, 529. aconeus internus, 529. pronator teres, 529. extensor carpi radialis, 529. flexor carpi radialis, 530. extensores digitorum longior et brevior, 530. abductor pollicis, muscle corresponding to, 530. flexores carpi ulnaris externus et internus, 530. flexor digitorum sublimis et flex. dig. pro- fundus perforans, 530. muscles of the haunch and hind- limb, 530. glutens maximus, 530. tensor fasciae latae, 530. biceps femoris, or vastus longus, 530. iliacus internus, gluteus medius et minimus, and pyriformis, 530. obturator externus et internus, the gemelli, quadratus femoris, vasti, and adductores, 530. Integumentary system, 530. the hump and cushion-like sole-pad of the drome- dary, 531. general character of the dermal envelope in Camelidae, 531. important changes co-existing with the shedding of the antlers in the solid-horned lluminantia, 531. design of the cloven condition of the foot, 531. Digestive system, 532. buccal cavity, 532. teeth, 532. tongue, 533. papillae of the tongue, 533. muscles of the tongue, 534. vessels and nerves of the tongue, 535. salivary glands, 535. oesophagus, 535. stomach, 535. paunch, rumen, ingluvies, or panse, 535. reticulum bonnet, or water-bag, 530. psalterium, manyplies, omasus, or feuillet, 537. reed, abomasus, or caillette, 537. ruminating function, 537. concretions found in the paunch and reticu- lum, 538. the Bezoar stones formed in the stomach of the chamois, 538. Intestinal tube, 539. intestinal glands, 539. Jiver, 540. pancreas, 541. spleen, 541. organs of circulation, 541. of respiration, 542. nervous system, 542. organ of vision, 543. of hearing, 543. of smell, 543. urinary organs, 543. reproductive system, 543. male organs, 543. female organs, 544. Stomach and Intestine, 293. Comparative Anatomy, 295. Infusoria, 295. Gregarina and Opalina, 295. Polygastria, 295. Hotifera,295. Eutozoa, 295. «. Echinococci, 295. /3. Cestoid and Trematoid divisions, 295. y. in many creatures closely allied to the pre- ceding, 290. Polypifera, 296. in hydras, 296. in the Actinia?, 296. in the compound Polyp, 29G. in the tubularian Polyp, 2%. in the cilio-branchiate Polyp, 297. Stomach and Intestine — continued. Acalephae, 297. Echinodermata. 297. Holothuriae, 297. Annelida, 297. Epizoa, 298. Crustacea, 298. Insecta, 298. stomach in the larva, 298. in the perfect insect, 298. the ingluvies or crop, 298. the gizzard, 298. the stomach, 298. Arachnida, 298. Acari, or mites. 299. Aranei, or spiders proper, 299. Scorpions, 299 Mollusca, 299. Tunicata, 299. Brachiopoda, 299. Lamellibranchiata, 299. Gasteropoda, 299. Pteronoda, 299. Cephalopoda, 299. Fishes, 300. oesophagus, 300. stomach, 300. intestine, 300. appendices pyloricae, 300. Reptiles, 300. oesophagus, 300. stomach, 300. intestine, 300. In the Batrachian reptiles, 301 in the Ophidian reptiles, 301. in the Chelonian, 301. Aves.301. stomach, 301. oesophagus, 301. ingluvies or crop, 301. proventriculus, or proper stomach, 301. gizzard, 301. intestine, 301. Mammalia, 301. Carnivora, 302. Insectivora, 302. Cheiroptera, 302. Pteropus, 302. Edentata, 302. Ruminantia, 302. Pachydermata, 303. Solipeda, 303. Rodentia entia, 303. Marsupialia, 303. Monotremata, 304. Cetacea, 304. Quadrumana, 304. general remarks, 304. absence of all digestive cavity, 304. simplest form of the digestive organ, as in the hydriform Polyp, 305. complex digestive organ, 305. Human Anatomy, 307. stomach, 308. form, 308. dimensions, 303. attachment, 308. situation, 309. serous coat, 309. muscular coat of, 310. longitudinal layer, 311. transverse or circular fibres, 311. oblique layer, 311. movements of the stomach, 311. in the fasting state, 312. at the commencement of digestion, 312. a. when a large quantity of food is hastily swallowed without mastica- tion, 312. b. when a small quantity of liquid food is taken, 312. c. when in the ordinary state of mode- rate distension, with food properly prepared by mastication, 313. at the later stage of digestion, 314. action of the pylorus, 315. simple eructation, or belching, 316. regurgitation, 316. vomiting, 316. rumination, 319. mucous membrane, 320. ruga?, 320. stomach-tubes, 320. 337. limitary or basement membrane which forms these tubes, 321. contents of these tubes, 321. tubes of the cardiac extremity in the dog, 322. tubes at the pyloric extremity of the organ, 322. lenticular glands, 324. matrix, 324. SB 3 734. ANALYTICAL INDEX Stomach and Intestine, human anatomy — continued. arteries of the stomach, 325. arteria coronaria ventriculi, or proper gas- tric artery, 325. the cesophageal and gastric branches, 326. arteria hepatica, 326. gastro-duodenalis branch, 326. gastro-epiploica dextra,32G. pancreatico-duodenalis branch, 32C. arteria pylorica, 326. arteria splenica, 326. gastro-epiploica sinistra, 327. yasa brevia, 327. veins of the stomach, 327. vena pylorica superior, 327. rena gastro-epiploica dextra, 327. vena gastro-epiploica sinistra, 327. capillaries, 327. changes in the stomach during digestion, 328. gastric juice, 328. its physical properties, 329. specific gravity, 329. quantity, 330. its chemical composition, 330. the gastric acid, 330. salts of the gastric juice, 332. its organic substance, or pepsine, 332. action of the gastric juice, 333. 334. peptone, 336. process of secretion, 337. small intestine, 339. duodenum, 340. superior transverse or hepatic portion, 341. descending or vertical portion, 341. inferior transverse portion, 341. jejunum and ileum, 341. muscular coat, 342. movements of the intestine, 342. peristalsis, 342. antiperistalsis, 345. mucous membrane of small intestine, 345. yalvulae conniventes, 346. inestinal tubes, or follicles of Lieberkuehn, 346. villi, 350. epithelium of the villi, 35J. the basement-membrane, 351. blood-vessels of the villi, 351. lacteals of the villi, 352. muscular constituents of the villus, 353. changes in the villi during digestion, 355. intestinal follicles, 356. agminate follicles, 356. capsule of the follicle, 358. vessels of the follicle, 358. contents of the follicle, 359. function of the agminate follicles, 359. solitary follicles, 360. racemose, or Brunn's, glands, 361. large intestine, 362. size and shape, 362. caecum (formerly the blind gut), 3G2. situation of the caecum, 3G3. its shape, 363. serous covering, 363. mucous membrane of the caecum, 363. apertures of the caecum, 3G3. the ileo-caecal valve, 363, vermiform appendix, 365. colon (formerly the great gut) ,.365. the ascending colon, 365. the transverse colon, 365. the descending colon, 3C5. the sigmoid flexure, 365. appendices epiploicze, 366. movement of the large intestine, 366. mucous membrane of the colon, 368. rectum, 368. the three portions : the first, or oblique segment, 368. the middle, or arcuate segment, 369. the third, or terminal portion, 369. structure of the rectum, 369. muscles of the anus, 369. sphincter ani internus, 3G9. sphincter ani externus, 369. the levator ani, 369. movements of the rectum, 370. defaecation, 370. mucous membrane of the rectum, 371. faces, 372. physical properties of the faeces. 373. odour and colour, 373. quantity evacuated, 374. specific gravity of the faeces, 374. mechanical composition, 374. chemical composition, 375. Stomach and Intestine, human anatomy — continued. intestinal gases, 376. 1. air may be introduced into the intestinal canal from without the body, 376. 2. gases may be developed in the alimen- tary canal from the decomposition of the food which it contains, 377. 3. it has been supposed that gases are set free in the intestinal canal by a kind of secretion or transpiration from the blood, 377. 4. probable source of intestinal gases pre- sent in diseased subjects, 378. arteries of the intestines, 379. the superior mesenteric artery, 379. the inferior mesenteric artery, 380. veins of the intestines, 380. the superior mesenteric vein, 381. the inferior mesenteric vein, 381. food, 382. nature of the food, 382. milk, 384. constituents of food, 384. 1. protein-compounds, 384. 2. hydro-carbons, 386. 3. hydrates of carbon, 386. 4. water, 387. 5. salts, 388. varieties of food, 3S8. animal food, 389. fat, 390. blood, 391. brain, 391. glands, 391. bone, 391 . eggs, 391. varieties of milk, 391. butter, 392. cheese, 392, vegetable food, 389. 393. corn, 393. proteinous constituent, 393. amylaceous constituent, 393. hydrocarbons, 393. salts, 393. leguminous seeds, 394. the potato, 394. succulent vegetables, 395. seasonings, 395. chloride of sodium, or common salt, 395. acid and acrid substances, 395. stimulants, 395. tea and coffee, 396. alcohol, 396. dietaries, 396. relations of digestion to nutrition generally,397. prehension, 397. mastication and insalivation, 397. deglutition, 398. gastric digestion, 398. intestinal digestion, 398. the bile, 399. development of the alimentary canal, 401. nerves of the stomach and intestine. See SYM- PATHETIC NERVE. Abnormal Anatomy of the stomach and intestine, 403. malformations, 403. 1. those which appear to depend on an arrested or deficient development, 403. 2. those attended by an excess of size, 403. 3. those which can only be referred to errors of development, the causes of whirh are un- known ; or to malformations of adjacent parts, 404. morbid conditions — size, 404. constriction, 404. dilatation, 405. thickness, 405. changes in the situation, 405. torsion of the intestine, 406. intus-susception, 406. abnormal conditions of its texture — softening, 407. hyperaemia, 408. haemorrhage, 409. inflammation, 410. catarrhal inflammation, 4 10. puriform inflammation, 411. croupy or diphtheric inflammation, acute gastritis, 414. dysenteric inflammations, 415. ulceration, 416. ulcer of the stomach, 416. lientery, 418. hypertrophy, 418. polypi, 419. tubercle, 419. cancer of the intestinal canal, 420. of the stomach, 421. stricture of the intestine, 422. TO THE SUPPLEMENTARY VOLUME. 735 Sympathetic Nerve, 423. I. cervical portion of the gangliated cord, 423. 1. the superior cervical ganglion, 423. a. communicating brandies, 423. b. ascending or carotid branch, 423. c. pharyugeal branches, 424. d. external lateral branches, -124. t. superior or long cardiac nerve, 424. /. communicating cord between the superior and middle cervical ganglia, 424. 2. the middle cervical ganglion, 424. 3. inferior cervical ganglion, 424. a. branches of communication between the ganglion and the seventh and eighth cervical nerves, 424. b. fine twigs proceeding from the ganglion, 424. c. inferior or small cardiac nerves, 425. II. thoracic portion of the gangliated cord, 425. a. communicating branches passing between the ganglias and the intercostal nerves, 425. b. small branches passing from the ganglia to the descending aorta, 423. c. chief branches leading to the thoracic gan- glia, 425. d. communicating cord between the last thoracic ganglion and first lumbar, 4i5. III. lumbar portion of the gangliated cord, 425. branches, 425. IV. sacral portion of the gangliated cord, 426. plexuses of the sympatnetic 42t». A. in the head, 426. 1. internal carotid plexus, 426. a. filaments communicating with the sixth pair of nerves, 426. b. great or deep petrosal nerve, 426, c. short branches passing through the outer wall of the cavernous sinus and joining the Gasserian gangliou on its inner surface, 426. 2. cavernous plexus, 426. branches, 4^6. 3. external carotid plexus, 427. B. thoracic plexuses of the sympathetic nerve, 1. cardiac plexus, 427. 2. plexus of the thoracic aorta, 428. C. abdominal plexuses of the sympathetic nerve, 428. 1. cceliac, solar, or epigastric plexus, 428. 2. superior mesenteric plexus, 429. 3. renal plexuses, 429. 4. spermatic plexuses, 429. 5. aortic plexus, 429. 6. inferior mesenteric plexus, 429. 7. hvpogastric plexus, 429. 8. inferior hypogastric plexuses, 430. 9. uterine plexus, 430. minute anatomy, 430. 1. tubular nerve fibres, 431. 2. structures which present a homogeneous flat- tened appearance and contain a number of oval nuclei imbedded in them at intervals, 431. 3. quantity of white fibrous tissue, 432. ganglia, 436. ganglionic corpuscles, 436. in Aves, 439. in Reptilia, 439. in Pisces, 439. in Invertebrata, 441. connection between the sympathetic and cerebro- spinal systems, 443. peripheral distribution, 418. development, 450. physiology, 455. properties of fibres of sympathetic, — sensory pro- perties, 458. mo:or properties, 459. the heart, 460. intestinal canal, — oesophagus, 4G4. stomach, 465. genito-urinary organs, 466. pupil, 466. influence of the sympathetic on the vegetative processes. 470. Tegumentary Organs, 473. § 1. what constitutes a tegumentary organ as distin- guished from any other, 47i. § 2. morphology of the integuments, 476. nails, 477. claw*, 477. hoofs, 477. horns, 478, glands, 478. hairs, 478. the porcupine's " quill," 478. feathers, 479. scales of fishes, 480. §3. histology of the tegumentary organs, 484. 1 . hydroid and actinoid polypes, 48 1. 2. integument of the Annulosa, including the Worms and Echinoderms, 485. Tegumentary Organs, histology — sontinwd. 3. integument of the Mollusca, including the ASCI. dians and Polyzoa, 488. excretionary integument of the Mollusca, 488. the membranous shell substance of Dr. Car- penter, 489. conversionary integument of the Mollusca containing cellulose, 493. 4. integument of the Vertebrata, 495, conversionary horny organs, 495. structure of hairs, spines, and feathers, 496. composition of the shaft of a hair, 496. cuticle, 496. cortical tissue, 496. medullary substance, 497. hair sac, 497. outer root-sheath, 497. fenestrated inner root-sheath, 497. imperforate root-sheath, 497. spines and feathers, 498. the shaft, 498. the quill. 499. tegutnentary glands, 499. sudoriparous glands, 500. scales of fishes, 501. structure of the endemn, 502. pigment of the enderon, 502, papillae of the enderon, 503. sensory appendages of the enderon, 503. the corpuscula tactus, 503. Panician bodies [see also the article Panf- cian Bodies}, 504. muscles of the enderon, 505. calcareous deposits in the enderon, 5G6. Uterus and its Appendages^ 547. OVARY: Normal Anatomy — form, 547. dimensions and weight, 547. position and connections, 548. component parts : 1. protecting parts or tunics, 548. peritoneum, tunica albuginea, 548. 2. parenchyma or stroma, 549. 3. Graafian vesicles, 550. 4. blood-vessels and nerves, 552. functions of the ovary — the developmental changes in the ovicapsules, and the process of emission of ova, 552. 1st stage, origin of the ovieapsules, 554. 2nd stage, growth, maturation, and prepara- tion for dehiscence, 555. 3rd stage, rupture or dehiscence, and escape of 4th stage, decline and obliteration of the ovi- capsules, 561. A. without impregnation, 561. B. after impregnation, 563. spontaneity of the emission of ova, 566. nature of the corpus luteum, 564. 569. classified arrangement of all the conditions which the Graafian follicle exhibits during evolution and involution, 570. summary of the conclusions which these conditions afford with reference to questions in obstetric and forensic medicine, 571. development and involution of the ovary — the origin of the ovary, and the alterations which it undergoes at different periods of life, 571. Abnormal Anatomy of the ovary — effects of extirpating the ovary, 573. deficiency and arrest of development, 573. atrophy and hypertrophy, 573. displacement, hernia, 573. diseases of the tunics — inflammation, 574. ulceration, rupture, 574. hypertrophy, calcification, 574. diseases of the proper tissues — hyperaemia, 576, inflammation, 576. suppuration, 577. simple, multiple, multilocular, and proliferous cysts, 578. the contents of ovarian cysts. 582. fluid contents of cysts, 582. quantity and rate of effusion, 582. composition of the contained fluids, 583. hydatids, 584. solid contents of ovarian cysts ; sebaceous and sudoriparous glands j fat ; hair ; teeth ; true bone, 584. origin of the solid contents of cysts, 586. foetus contained in the ovary (?); the question of ovarian gestation considered, 586. examples of supposed ovarian gestation, 587. solid enlargements of the ovary, 591. cartilaginous and ossific formations, 591. cancer, colloid or alveolar ; medullary and scir- rhous, 591 . scrofulous tubercles, 593. SB 4 736 ANALYTICAL INDEX. Uterus and its App>. ndages — THE PAKOVAKIUM : structure and development, 593. abnormal states, 597. THE FALLOPIAN TUBE OR OVIDUCT : Normal Anatomy — form ; dimensions, 597. situation and connections, 598. separate parts and divisions, 509. internal orifice, 509 uterine portion of the tube, GOO. canal, 600. external orifice, 600. pavilion or infundibulum, C01. fimbrije, 602. tubo-ovarian ligament, 602. structure of the coats or tunics, COS. blood-vessels and nerves, 604. functions of the Fallopian tube. reception and transmission of ova and spermatic fluid, 605. first steps in the process of impregnation, 608. the changes which the ovum undergoes in the tube, development of the Fallopian tube. formation of the oviduct out of the duct of Miiller, 613. Abnormal Anatomy of the Fallopian tube — defect and imperfect development, 614. peculiarities of construction, 615. displacements, 616. obliteration of the canal, 617. hyperaemia ; inflammation 617. collections of fluid within the tube ; blood ; serum; pus, 617. cysts, 620. fibrous tumours, 620. tubercle ; cancer, 620. rupture of the tube walls, 620. Fallopian tube gestation ; various forms, 6.0. UTERUS: Normal Anatomy — situation and position, 623. form, 624. dimensions and weight, 624. regional divisions : the fundus ; the body; the cer- vix, 624. external surface, 626. internal surface, and cavities of the body and cer- vix, 6'26. structure and arrangement of the tissues composing the body of the uterus, 630. peritoneal coat, 631. middle or muscular coat ; composition; course of the muscular fibres, 631. mucous or deciduous coat ; its composition, 635, utricular glands or follicles, 636. structure and arrangement of the tissues composing the cervix uteri, 638. muscular coat, 638. mucous coat ; epithelium. 638. papillae, 639. mucous follicles, 640. blood-vessels of the uterus, 640. lymphatics, 641. nerves, 641. development and metamorphoses of the uterus at different periods of life. a. origin of the uterus, and its condition during foetal life, 642. b. the uterus from the time of birth to puberty, c. the uterus during menstrual life, 644. d. the uterus during gestation ; the gravid or fully developed uterus, 644. size and weight, 645. alterations during gestation in the form of the body and cervix uteri, 645. position, actual and relative, of the uterus during gestation, 647. alterations in the special coats and tissues, the peritoneum, 649. the muscular coat, 649. the blood-vessels, 651. nerves ; the question of enlargement of the uterine nerves during pregnancy, 651. mucous or lining membrane of the uterus; development into the decidua ; decidua vera and reflexa, 652. histology of the decidua, 657. e. the uterus after parturition, 658. the process of involution of the gravid uterus, 658. changes in dimensions and weight, 658. metamorphosis and restoration of the compo- nent tissues, 659. /. the uterus after the menstrual epoch ; senile atrophy or involution of the uterus in advanced life, 661. Uterus and its Appendages — continued. functions of the uterus — a. the office of the uterus in menstruation, 062. periods of duration and recurrence of this function, 662. quantity, 663. nature of the catamenial discharge, 663. composition of the menstrual fluid; analysis, 663. microscopic examination, 663. the unmixed menstrual fluid; its analysis, 664. source of the menstrual flux, 605. the means by which the blood escapes during healthy menstruation, 660. the purpose of menstruation, 666. the relation of this function to the maturation and emission of ova examined, 667. the purpose of the flux, 670. b. the office of the uterus in insemination, 671. c. the office of the uterus in gestation, 672. d. the office of the uterus in parturition, 672. general sketch of the labour process, 072. the peristaltic action of the uterus, and its cause, 673. the rhythmic action of the uterus, and its cause, 674. influence of the different nervous centres upon the uterus in paiturition, 675. the exciting cause of labour, 677. Abnormal Anatomy of the uterus — defective development, 678. 1st class, congenital defect?, 678. the various abnormal forms of the uterus, arising from imperfect coalescence of the primitive uterine halves (commonly termed double uterus), arranged in four groups: Group I. uterus bipartitus, 678. Group II. uterus unicornis, 67f>. Group III. uterus bicornis, 679. Group IV. uterus bilocularis, 680. 2nd class, incomplete development at the time of puberty. the pre-pubertal uterus, 681. anomalies of form of the uterus, 682. antiflexion, 682. retroflexion, 683. lateral inflexion, 683. anomalies of position of the uterus, 683. obliquity, 683. anti- and retro-version, 683. hernia of the uterus, 684. prolapsus, 684. elevation, 684. inversion, 684. anomalies of size of the uterus, 686. atrophy, 686. hypertrophy, 687. pathological conditions of the separate tissues of the uterus, 687. 1. pathological conditions of the peritoneal coat; acute and chronic metro-peritonitis, 687. 2. pathological conditions of the subperitoneal fibrous tissue ; peri-metritis, 688. 3. pathological conditions of the muscular coat, 689. its diminished and increased consistence, 689. parenchymatous inflammation ; metritis, 689. fibroid, or fibrous tumour of the uterus ; interstitial, sub-peritoneal, and sub- mucous fibroid; fibrous and muscular " polypi," 689. 4. pathological conditions of the mucous coat, 692. simple hypertrophy; dysmenorrhceal mem- brane, 692. hypertrophy of the follicular structures of the uterine mucous membrane ; follicu- lar " polypi ; " mucous " polypi ; " cysts, 692. hypertrophy of the filiform papilla? of the cervix (pseudo-ulcer), 693. simple inflammatory hypertrophy, with extroversion of the cervical mucous membrane (pseudo- ulcer;, 693. catarrhal inflammation of the inucous coat of the uterus; endometritis; leucorrhcca, 694. ulceration of the mucous coat ; erosion, abrasion, and excoriation, 604. distensions of the uterine cavity — hydrometra, 697. haematometra, 697. physometra ; tympanites uteri, 698. hydatids, 698. narrowing and obliteration of the uterine cavity— atresia of the os uteri, cervical canal, and cavity of the uterine body, 698. TO THE SUPPLEMENTARY VOLUME. 737 Uterus and its Appendages— continued. pathological conditions involving several of the uterine tissues — cancer, 699. cancroid ; epithelial cancer ; cauliflower excre- scence, 700. corroding ulcer, 700. tubercle, 701. solutions of continuity; rupture; perforation, 701. pathological conditions of the uterus after par- turition— irregular contraction ; hour g1a*s contraction (arre ted peristaltic action), 702. incomplete and retarded involution, 702. puerperal inflammation, endo-meti itis, 7i>2. metro-phlebitis, 703. metro-peritonitis, 703. blood dyscrases, 704. LIGAMENTS OP THE TJTEKUS: normal anatomy — the broad ligament, 705. the utero-sacral ligaments, 705. the utero-vesical ligaments, 705. the round or sub-pubic ligaments, TOo. VAGINA : normal anatomy — dimensions, 70G. external surface, 706. composition, 706. internal surface, 706. arteries; veins; lymphatics; nerves, 707. uses of the vagina, 707. abnormal anatomy — anomalies of form and size, 707. displacement^. 7 ;. solutions of continuity, 707. infl immation, 707. epithelial desquamation, 707. serous and sanguineous infiltration, 707. Uterus and its Appendages — con United. abscess ; ulceraiion ; gangrene, 7C8. cjsts and tumours, 708. cancer, 7C8. EXTERNAL ORGANS OF GENERATION : normal anatomy — the mons veneris, 708. labia, 708. clitoris, 709. nymphse, 710. vestibule, 710. vaginal orifice and hymen, 710. origin, varieties, and signification of the hy- men, 710. sebaceous and muciparous glands and follicles of the vulva; vulvo- vaginal gland, 711. bulb of the vagina ; pars intermedia; constrictor vaginae, 712. blood-vessels and nerves of the external organs, abnormal anatomy — labia, 714. ' clitoris, 714. nymphae and vestibule, 714. hymen and ostium vaginae, 715. PLACENTA : normal anatomy — form, 715. dimensions and weight, 715. total surface ; amniou ; chorion : foetal blood' vessels, 715. uterine surface, 716. circumference, 716. substance, 717. tufts and villi, 717. terminations of the total vessels, 718. decidua, 718. terminations of the maternal vessels, 719. development of the placenta. of the total portion, 719. of the maternal portion, 720. functions of the placenta, 721. GENERAL INDEX TO THE CYCLOPAEDIA OF ANATOMY AND PHYSIOLOGY. The following have been accidentally omitted from the GENERAL INDEX : Aortic plexus of nerves, s. G03. superior, s. 641, note. inferior, s. 641, note. Aposepedine, or caseous oxide, iii. 359. mode of obtaining, iii. 359. Lacteals, i. 20. coats of the, i. 22. discovery of the, i. 20. minute anatomy of the, i. 21. specific uses of the, i. 33. valves of the, i. 22. villi of the, i. 22. Ligaments in particular : — accessory, i. 251. alar, i. 251. of ankle-joint, i. 154. coraco-acromial, i. 359. coronary, i. 251. costo-coracoid, i. 360. crico-thyroid, i. 251. crucial, i. 251. deltoid, i. 152. falciform, i. 13. Fallopian, i. 5, note a. fibulo-tarsal, anterior, i. 152. middle, i. 152. intermuscnlar, i. 217. external, i. 217. internal, i. 217. lateral, i. '251. internal, i. 152. mucous, of the knee, i. 251. of patella, i. 253. teres, i. 113. 251. thyro-hyoid, i. 251, tibio-tarsal, anterior, i. 152. internal, i. 152. umbilical, i. 9. of urinary bladder, i. 388. Ligaments in general : — capsular, i. 250. 359. elastic, i. 251. structure of, i. 250. uses of, i. 250. GENERAL INDEX. The Arabic figures refer to the paging; the Roman numerals to the Volumes j and s. to the Supplementary Volume. ABDOMEN (in anatomy generally), i. 1. in Arachnida, 1. I. in Articulata, i. 1. in Vertebrata, i. 1 . ABDOMEN (in human anatomy), i. 2. arteries, i. 14. cavity, abdominal, i. 16. See CAVITY. lymphatics, i. 16. muscles, and their aponeuroses, i. 4.* nerves, i. 16. distribution of the nervus vagus in the abdomen, iii. 889. parietes, physiological action of abdominal, i. 16. serous membrane of the. See PERITONEUM. superficial fascia of, ii. 230. walls, and structures composing the walls, i. 2 — 11. peritoneal investment of the walls of the abdomen, iii. 944. veins, i. 15. congenital malformations, i. 508 ; iv. 950. morbid conditions, i. 509. Abdominal aorta, i. 181 . 189. See AORTA. aneurism of the, i. 192. branches of the, i. 194. Abdominal artery, iv. 823. Abdominal cavity ( in human anatomy ), i. 500. See CAVITY. Abdominal fasciae, s. 138. Abdominal plexus of sympathetic nerve, s. 428. nerve, large, iv. 761. small, iv. 702. Abdominal ring, external, i. 4,* 5. internal,!. 7- 12. Abdominal veins, i. 15. Abducentes oculi nerves, iii. 70?. Abduction, a motion of joints, i. 256. Abductor minimi digiti muscle, ii. 520. relations and uses, ii. 520. minimi digiti pedis muscle, ii. 358. pollicis mantis muscle, ii. 5i9. relations and uses, ii. 519. pollicis pedis muscle, ii. 358. Aberration of light, chromatic, iii. 335 ; iv. 1438. 1441. correction, iii. 335 spherical, iii. 334 ; iv. 1438. 1441. correction, iii. 334. Herschel's doublet, iii. 334. Abnmmuf, reed, caillette, or fourth stomach, of Rumi- nantia. ii. 11; s. 537. Abranchia, an order of Amphibia, i. 91, etseq. characters of the order, i. 91 . Aborigines, causes of the tendency of, to extinction, iv. 1341. 1365. Abscesses of the axilla, i. 3G2. of tlie bladder, i. 397. of the bones of the face, ii. 220. of the cancellated structure of the tibia, iii. 13G. caused by a foreign body impacted in the intestine, i. 187. cerebral, iii. 720 c. chronic, of cellular tissue, i. 515. of the cornea, ii. 177. of the fore-arm, diagnosis and treatment of, ii. 308. of the ischio-rectal spaces, i. 177. 186. of knee-joint, iii. 61, et seq. of the liver, idiopathic, iii. 190. from external injury, iii. 190. in the loins, connected with diseased Tertebrae, i. 452. lobular, iv. 1395. mode of production of, iv. 1395. lumhar, or psoas, i. 187. its resemblance to inguinal hernia by direct descent, ii. 760. mode of cicatrisation of, i. 601. Abscesses — continued. of the muscular substance of the heart, ii. 636. in the neck connected with diseased vertebrae, i. 452. simple, of the nose, iii. 738. of the parotid gland, iv. 430. of the pharynx, iii. 954. phlegmonous, of elbow, ii, 63. of the prostate gland, iv. 156. psoas, i. 187. case of, ii. 797. of scapular region, chronic, iv. 438. in scrofulous affections of the bones, i. 450, 451. scrofulous, of the kidney, iv. 257. of vagina, *. 70S. Absorbent system, iv. 444. See LYMPHATIC SYSTEM. Absorbents in arteries, i. 224. of the bladder, i. 387. of fore-arm, ii. 362. of testicle, iv. 9*2. of the mammae, ill. 249. of thymus gland, iv. 1094. Absorbent system of birds, i. 327. See AVES. absence of, in the Conchiferous Mollusca, i. C97. ABSORPTION, i. 20. cutaneous absorption, i. 31. description of the absorbent system, i. 21. mode in which the absorbents act, i. 28. specific uses of the different parts of the absorbent system, and the relation which that system bears to the other vital functions, i. 32 venous absorption considered, i. 24 ; iv. 1390. Absorption, in animalg generally, i. 142. oi the earthy particles of bones, i. 444. See also BONE. without the secretion of purulent matter (dry caries}, with secretion of purulent matter, i. 444. ACALEPHJJ (class of Invertebrate Animals), i. 35. 108. circulation, i. 43. 654. digestion, i. 41. s. 297. division of the class, i. 36, 37. generation, i. 45 ; ii. 409 ; s. 20. 21. [129.] geographical distribution, i. 46. locomotion, i. 37. names and characters, i. 36. motility and sensation, i. 40. remedies for the sting of Acalephse, i. 45, note a. respiration, i. 44. secretion, i. 45. 175. list of Acalephae possessing the property of luminous- supposed seat of the sting'ng quality possessed by many of the Acalephae, iii. 201. absence of nervous and muscular fibre in, iii. 533. 602. spermatozoa in Acalephae, iv. 499. See also ANIMAL KINGDOM Acanthias niger, skeleton of the, iii. 963. Acanthocepltala, an order of Entozoa of Rudolph!, ii. 11G. 1-27. 133. See ENTOZOA ; Sterclmintha. Acanihopterygii, an order of Fishes, iii. 956. Acanfhotheca, a family of Entozoa, ii. 116. See ENTOZOA. Acanthoztia, spermatozoa in, iv. 499. Acardia, or absence of the heart, ii, 630. Acari, or mites, skin of the abdomen of, i. 201. digestive system, i. 202. 203 ; s. 299. respiratory system, i. 204, 205. Acarintz, spermatozoa in, iv. 492. Acarus folliculorum, iii. 730. Accelerators urinae muscles, iii. 915. 929 ; iv. 125. action of, iv. 1255. Accessory glands of Gast«ropoda, ii. 388. See GASTERO- PODA. Accessory ligaments, i. 251. nerve, i. 731. 742 GENERAL INDEX. Accessory parotid gland, or socia parotidis, iv. 423. vesicles, ii. 423. See GENERATION, ORGANS OF. Accipenser sturio (sturgeon), skeleton of the, iii. 905. Acclivitas intercondyloidea, or spine of the tibia, it. 168. Acephiila, spermatozoa in, iv. 487. ova of, s. [108.] structure and formation of, s. [109.] Acephali, or foetuses without a head, iv. 958. acephali in the form of a rounded mass without ex- tremities, iv. 960. acephali in same form, with indication of feet, iv. 960. acephali in which the trunk is more developed, with- out a head and thoracic extremities, iv. 961. acephali without a thorax and without superior limbs, and composed of an abdomen, genital organs, and in- ferior limbs, iv. 961. acephali in which the trunk is more developed, with an imperfect thorax, iv. 961. acephali with a trunk composed of a thorax and an abdomen, with superior and inferior limbs, iv. 962. acephali in which some cranial bones are found, iv. 962. body and extremities perfectly developed, having a neck surmounted by the ears, iv. 962. acephali composed of the trunk only, without indica- tion of limbs, iv. 962. Acephalia, i. 744; ii. 219; iii. 718. Acephalia spuria, iv. 954. See Acrania. Acephalocyst, i. 517; ii. 117. organisation of, ii. 117. mode of reproduction of, s. 25. of the brain, iii. 720 E. of the human liver, iii. 196. in veins, iv. 14((2. Acephalocystis endogena, or pill-box hydatid of Hunter, ii. 117. exogena, ii. 117. Acephalo-cystus, or hydatid, of the upper jaw-bone, ii. 220. Acerotherium, the. See PACHYDERMATA. Acervulus of Soemmering, iii. 635. Acephalous mollusks, iii. 364. See MOLLUSCA. Acetabula, or suckers, of Dibranchiata, i. 528. See CEPHA- LOPODA. Acelabulum, i. 249; ii. 776; s. 116. cartilHge of the acet-ibulum, ii. 777. fibro-cartilage, ii. 777. fovea or sinus, ii. 777- glands of Havers, ii. 777, 778. incisura acetabuli, ii. 776. ligaments, ii. 777. supercilium acetabuli, ii. 776. abnormal conditions of the, it. 797. fractures of the, ii. 802— 804. a brim, or circular border of, s. 116. Acetic acid, or vinegar, action of, on fibrin, iv. 1G6. considered as an article of food, s. 395. Achagua Indian, portrait of, iv. 1359. Achcta domestica, or house-cricket, 864. Achillis tendo, i. 150. Achromatic lenses, how obtained, iv. 1438. Achromatopsy, or insensibility of the eye to colours, iv. 1452. relative frequency of the affection, iv. 1453. hereditary tendency, iv. 1453. influence of sex, iv. 1454. hypothesis as to causes of this affection, iv. 1454. congenital achromatopsy, iv. 1454. dichromatic Daltonism of Wartmarm, iv. 1454. polychromatic D.iltonism of Wartrnann, iv. 1455. list of the most common confusions of colour, iv. 1456. cases, iv. 1456, 1457. non-congenital achromatopsy, iv. 1457. permanent, iv. 1457. cases, iv. 1457, 1458. temporary, iv. 1458. cases, iv. 1458—1460. cause of the confusion of colours, iv. 1460. hypothesis, iv. 1460, 1461. remedial measures, iv. 1461. Acini, ii.4«l. 483. of the liver, iii. 165. of duodenal gland, s. 361. ACIDS, AMMAL, i. 47. See BOVE; FAT; MILK; URINE. Acids, in animals and vegetables, i. 125. considered as articles of food, s. 395. Acortnia, or congenital want, and detective formation, of the trunk, iv. 963. n. only a part of the head formed, Iv. 963. b. superior parts of the body formed, without the in- ferior limbs, iv. 964. c. monopodia, iv. 964. d. svmpodia, iv. 964. e. original defective formation of the pelvis, iv. 965. /. detective development of the spinal column, iv. 965. Acorn-shells, i. 683. See CIRRHOPODA. Acoustic nerve, ii. 539. See Auditory nerve. Acoustics. See HEARING (physiology of) ; Sound. Acrania, what is the cause of, iv. 957. Acrid substances considered as alimentary, s. 395. ACRITA (a primary division of the animal kingdom), i. 47. nervous system of the, iii. 601. Acromial artery, i. 360. 3G3. inferior branch, i. 364. superior branch, i. 363. Acromial nerves, iv. 753. communicating branches, iv. 753. communicant noni.or internal descending cervical, iv. 753. Acromion process, i. 360 ; ii. 157, 1(58; iv. 434. 600. fractures of the, iv. 600. mode of union, iv. 600. in Carnivora, i. 476. See CARNIVORA. Acrydium, nervous system of, iii. 610. Actinia, a genus of Polypifera, iii. 601. nervous filaments of the, iii. 601. digestive organs of, s. 296. mo le of reproduction of the, s. 17. generative system of, ii. 409. ova of, s. [127]. biliary apparatus of, iv. 445. structure of the integuments of, s. 484. Actinia alcyonoidea, a species of Polypifera, iv. 39. sociata (Ellis), Zoanthus (Cuv.), a genus of Poly- pifera, iv. 20. Actiniadce, a family of Polypifera, iv. 20. 38. characters of the family, iv. 20. 38. genera, iv. 20.38. fibrous arrangement of the contracting portions of the body, iii. 533. mode of reproduction, iv. 40. number and description of ova, iv. 40. muscular and nervous system of, iv. 40. stinging sensation produced by, on the skin, iv. 40. their voracity and power of long fasting, iv. 40. their power of reproducing lost parts, iv. 40. Actinism, iv. 1437. Actinophrys, or sun animalcule, iv. 12. mode of reproduction of the, s. 8. Actmurus, genus of Rotifera, iv. 407. Actions of animals generally, i. 141. Activity of animals, property of, iii. 35. generally proportionate to the respiration, iii. 35. See LOCOMOTION. Aculeata, a cection of insects of the order Hymenoptera, ii. 865. characters of the section, ii. 865. Adamas, or enamel of teeth, iv. 865. Adam's apple, iii. 102. 112. 573. physiognomical character of, iii. 573. Adder, puff ( Vipera), poison fangs of the, iv. 291. ova of the, s. 55. Additamentum suturaa lambdoidalis, i. 737. squamosas, i. 737. Adduction, a motion of joints, i. 256. Adductor brevis femoris muscle, s. 137. longus femoris muscle, s. 137. magni.'S femoris muscle, s. 137. magnus muscle, nerve for, iv. 765. ossis metacarpi s. opponens, ii, 521. minimi digiti, muscle, ii. 521. relations and use, ii. 521. pollicis muscle, ii. 520. relations and uses, ii. 520. pollicis pedis muscle, ii. 358. Adephaga, a sub-tribe of Insecta, ii. 859. ADHESION, i. 49. development of granulation, i. 52. modifications, i. 53. mucous membranes not capable of adhesion, i. 55. organisation of serous membranes, i. 51. rudiments of blood-vessels, i. 51. union by the first intention, i. 49. by the second intention, i. 50. Adhesion of bones, or adhesive ossific inflammation of Hunter, i. 444. formation of callus, i. 444. theories of the process of, 444, 445. ancient notion of " osseous juice," i. 444. theories of Duhamel, Haller, Hunter, and others, i. 445. imperfect union of bones, i. 447. causes of, i. 447. process of re-union, i. 446. Adhesion of the cranium, i. 746. Adhesion, gelatinous, ii. 742. ADIPOCERE, i. 55. discovery of, i. 55. chemical properties of, i. 56 ; ii. 235. ADIPOSE TISSUE, i. 56. deposition of fat, mechanism of, i. 60. distinguishing characters between the cellular and adipose tissues, i. 57. microscopical and atomical construction of animal fat, i. 58. pathological conditions of adipose tissue, i. 61. proximate principles of animal fat, i. 59. quantity and physical qualities of adipose tissue in various situations, i. 57. See FAT. of mammae, hypertrophy of, iii. 254. in insects, ii. 975. See INSECTA. GENERAL INDEX. 743 Adventitious products. See PRODUCTS, ADVENTITIOUS. Aerometer, construction and mode of operation of the, iii. 32. 33. Afftrent functions of nerves, iii. 720 I. nervous fibres, iii. 646. Africa, origin of the people of the group of African na- tions, iv. 1364. cranium of ihe natives of, iv. 1321, et teg. variety in the complexion of the different races of, iv. 1334. See VARIETIES OF MANKIND. African group of languages, iv. 1347. African races, physical and mental characters of the, iv. 1352. See Xegrocs; VARIETIES OF MANKIND. Affusion of cold water, beneficial effects of, ii. 681. Agnlma Okenii (fig. 8.), i. 38. Agastrica, the term proposed, iii. 532. Agony, or death-struggle, a sign of approaching death, AGE, growth, i. 65. h» iglit, weight, and strength, of the human body at different ages, i. 74. maturity, i. 76. decay, i. 77. osseous system at old age, i. 439. relations of, with animal heat, ii. C62. syncope caused by old age, i. 798. Ages of organised bodies, i. 123. Agouti (Dasyprocta), anatomy of the, iv. 373, et seq. mode of locomotion of the, iii. 454. Agrostis segetum, ravages of the larva of, in turnip-fields, n M)7. Ai, the. ii. 47, et seq. See EDENTATA. pelvis of the, s. 162. Air, atmospheric, constituents of, in its free state, iv. 325. and in a vitiated condition, iv. 326. its absorption oi the rays of light transmitted through it, iv. 1438. bulk of the air expelled in expiration, iv. 352. eflu.-ion of, into the cellular tissue, i. 516. apparatus for renewing the air in the lungs of the human species, iv. 333. intermixture of air in the upper and lower respiratory apparatus, iv. 3G2. actions between the blood and the atmospheric air, iv. 36-2. atmospheric, changes effected in, by the respiratory apparatus of animals, i. 133; iv. 342. quantity of carbonic acid gas in the expired air, iv.345. effects of period of the dny, iv. 346. digestion, iv. 346. fasting, iv. 347. alcohol, iv. 347. conditions of the mind, iv. 348. exercise, iv. 348. temperature, iv. 348. the seasons, iv. 349. barometric pressure, iv. 349. age, sex, and constitution of body, iv. 349. the respiratory movements upon the evolution of carbonic acid from the lungs, iv. 351. frequency of the respiratory move- ments, iv. 351. bulk of the air expelled, iv. 352. stoppage of the respiratory move- ments for a time, iv. 3-V2. quantity of. drawn into, and expelled from, the lungs, iv. 339. during quickened or forced respiration, iv. 340. pneumatic apparatus of the feet of flies, iii. 443. and of the tree fro?, iii. 448. air swallowed by the Diodons and Tetrodon8. See LLNGS ; RESPIRATION, ORGANS OF. minute structure of the, s. 270. epithelium of the air-passages and cells, s. 270. elastic tissue of the air-cells, s. '272. ^//•-passages of birds i- 345. See AVES. A-ke, the Chinese heteradelph, iv. 969. Akyano-blepsis. See Achromatopsy; VISION. Ala, or wing, of the ilium, a. 115. Alnctaja (Mus jaculus), anatomy of the, iv. 372, ct seq. Alee majores, i. 726, 727; ii. 213. anterior border, i. 728. anterior surface, i. 727. Ala; — continued. external border,!. 727. inferior surface, i. 727. posterior border, i. 7'27. superior border, i. 727. upper surface, i. 727. Alts minores, i. 726. 728 ; ii. 213. inferior surfaces, i. 728. upper surfaces, i. 728, Alec cordis of insects, i. 2f 6. Ala; of nose, cartilages of the, iii. 726. Alar ligaments, i. 251 ; iv. 521. of knee, iii. 46, 47. reins, iv. 1407- Albatross, great, flight of the, iii. 429. Albinismus See ALBINO. ALBINO, i. 83. allusions of the ancients, i. 84. eye of, i. 84. found in all species of Mammalia, i. 86. habit and constitution of the, i. 85. partial whiteness of the body in some cases, i. 86. physical causes — hypotheses, i. 86, 87. Dr. Sachs, the albino, iv. 1461. Albugineotis fibre of Chaussier, ii. 263. Albugo of the cornea, ii. 177. ALBUMEN, or white of egg, i. 88. chemical properties, i. 88, 89 ; iv. 162 ; s. 147. coagulation, cause of, i. 90. sulphate of albumen, i. 8'». tests of the presence of albumen, i. 90. considered as the material necessary for the nutrition of the tissues, iii. 743. in the composition of the blood, i. 410. red i-ctionof every protein compound to albumen, iii.742. change from albumen to fibrin in the process of assimilation, iii. 743. proportion of albumen contained in some of the animal products, iv. 167. mode of obtaining pure albumen, iv. 167. appearances presented by albumen with reagents, iv. 167. vegetable albumen, iv. 169. method of determining the presence of, in organic substances, iii. 795. 805. quantitative analysis of, iii. 798. morbid conditions of the, i. 422. albumen as an adventitious product, ir. 91. a. albumen in the secretions, iv. 91. albuminaria from an unnatural state of the blood, iv. 91. albuminaria from morbid states of the genito- urinary organs, iv. 92- albuminaria from accidental admixture of ge- nital products, iv. 92. albuminaria from a doubtful cause, iv. 93. b. albumen retained, iv. 93. See also OVUM. Albuminaria, or albuminous urine, iv. 91. See ALBUMEN. Albuminose, or peptone, s. 336. chemical composition of, s. 336. Alcohol, use and abuse of, ii. 15. operation of, on the digestive powers, ii. 14. considered as an article of food, s. 396. effect of, on the actions of the heart and circulating system, i. 724. 797. effects of, on the quantity of carbonic acid gas in the expired air, iv. 347- Alcyoncellum, a family of Porifera, iv. 65. characters of the family, iv. 65. ova of, s. [127]. Alcyonia, luminousness of, iii. 198. Alcyonidee, a family of Polypifera, iv. 19. 24. characters of the family, iv, 19. 24. nerves and muscles not discernible in the, iii. 5"*3. Alcyonidium elegans, a genus of Polypifera, iv. 25—29. nutrition of, iv. 27. moJe of reproduction, iv. 27. gemmae, iv. 28. Alcyonidium stellatum, iv. 29. vascular system of, iv. 29. reproduction of, iv. 29, 30. Alcyonium bnrsa, electricity of the, ii. 82. ova of, s. [127]. Aleiiritcs triloba, fat of the, i. 58. Algce, mode and organs of reproduction of, ». 212. reproducton by means of zoosporr s, s. 212. under the most simple conditions, s. 212. the confervoid Alga?, s. 213. the frond, s. 213. the Ulvaoeae, ?. 214. zoospores developed in an organ specially destined to the purpose, s. 214. zoosporous reproduction in the olive-coloured Alga, s. 214. fructification in the Fucacea?, s. 215. the antherozoids of the Fucacea? compared with the zoospores of the other olive-coloured Algae, s. 216. zoosp »rous reproduct'on in the family of Vau- cheriaceae, s. 216. 741 GENERAL INDEX. Alga; — continued. zoosporoug reproduction in the Saprolegnia ferox, s. 217. in the Pilobolus, s. 218- in some of the Fungi, s. 218. reproduction by conjugation, s. 218. in the Desmidiae, $. 218. in the Zygnemaceae, s. 219. in Palmoglea macrococca, s. 220. condition under which conjugation takes place among the Alga?, s. 220. plants obtained by the germination of the zoo- spores of Saprolegnia, producing reproductive organs of an entirely different character, s. 220. reproductive organs of the red Algae or Florideaa, s. 221. the first form — a polyspore, s. 221. the second form — a tetraspore, s. 221 . the third form — the antheridium, s. 221. reproductive organs of the Characea?, s 222. the antheridium of Chara, s. 222. summary, s. 222. of the two kinds of zoospores, s. 223. of germs, whose development is dependent on the combination of two organs, the reproductive functions of which are complementary each to each, s. 223. AJgce, esculent, properties of the, ii. 13. Algiers, Arabs of, iv. 1357. Kabyles of, ch-iracters of the, iv. 1357. Alkaline salts in the composition of the blood, i. 410. in disease of the blood, i. 423. Alkaloids, vegetable, regarded as proximate principles, iii. 152. Alimentary canal, calculi formed in the, iv. 84. basement membrane of the. iii. 4S7. in comparative anatomy. See under each heading. Alligator, anatomy of the, iv. 291, et seq. teeth of, iv. 895. vocal organs and voice of the, iv. 1502. Allotreta, a sect:on of Polygastric animals, iv. 5. Almonds, essential oil of, effect of, on the action of the heart, i. 797. Alveolar artery, i. 490 ; iii. 733. Alveolar border of lower jaw-bone, ii. 214. or inferior, border of superior maxillary bone, ii. 209. Alveolar veins, iv. 1404. Alveoli, ii. 209. pulmonum, s. 268. Alvus, i. 1. Amaroucium, a genus of Tunicata, iv. 1190, et seq. characters of the genus, iv. 1190. Ambergris, formation of, iv. 85. in the human intestine, iv. 85. Amblyopia, iv. 1465. Amblyrhynchus ater, food and teeth of the, iv. 892. America, mean age at death of the population of, con. trasted with that of England, iv. 1471. American aborigines, capacity of the skulls of, iii. 666. custom of compressing the skull, iv. 1360. languages of the, iv. 1359. physical and mental characters of the, iv. 1358. causes of the tendency to extinction in the aborigines, iv. 1341. method by which the relation between the different words of the languages of the aborigines, that con- stitute sentences, is indicated, iv. 1346. Americans, peculiarities in the physical conformation of the Anglo-American race, iv. 1330. American Tapir, anatomy of the, iii. 803, et seq. See PA- CHYDERMATA. Aiu'rylhro-blep*is. See Achromatopsy; VISION. Amcebeeadce (proteiform animalcules), a family of Poly- gastric animalcules, iv. 4. characters of the family, iv. 4. Amorphozoa, or sponges, iv. 65. See PORIFERA. Ammonia, method of determining the presence of, in or- ganic substances, iii. 804. carbonate of, composition of, iii. 151. Ammnnitidce, fossil sheU of the, i. 520. characters of the family, i. 520. Amnion, the, s. 715. Ampfiiarthronis, form of articulation, i. 255. AMPHIBIA (a clnss of Vertebrated Animals), i. 90. 115. characteristics of the class, i. 90. chyliferous system, i. 601. dermal or tegumentary system, i. 102. digestion, organs of. i. 95; iii. 175. divisions of the class, i 91. generative organs, ii.420; iv. 161. hearing, organ of, i. 101. lymphatic and lacteal system, i. 96. metamorphosis, i. 106. mode of progression of, iii. 448. muscular system, i. 95; iii. 543. nervous system, i. 100; iii. 620. osteology, i.9l. 438. respiration, i. 98; iv. 1020; s. 278. reproduction, i. 105. re.-toration of lost parts, i. 104. s mguiferous system, i. (J6. AMPHIBIA — continued. smell, organ of, i. 102. taste, organ of, i. 102. transpirat on and secretion, i. 104. vision, organ of, i. 101. See also ANIMAL KINGDOM. Amphisbcena, mode of progression of the, iii. 448. Amphitrite alveolata, ciliary motion in, i. 619. Amphioxus lanceolatns, anatomy of the, iii. 615. 822. neuro-skeleton, iii. 615. nervous system, iii. 616. Amphipneurta, an order of Amphibia, i. 91, et seq, characters of the order, i. 91. Ampulhe, membranaceous, ii. 537. structure of the, ii. 538. nerves of the, ii. 542. Ampullary sinus, ii. 530. 537. Amputation of the arm, i. 218. • Amputation of hand, different parts of, remarks on, ii. 529. Amputations of the leg, iii. 134. circular and flap amputations, iii. 134. precaution with respect to the projecting angle which the tibia, when amputated, presents anteriorly, iii. 135. arteries of the leg requiring ligatures in amputation, iii. remarks on the application of artificial legs, iii. 13(5. Amyelia, iii. 713. Amygdala of cerebellum, iii. 689. 692. Amygdala, or tonsils, iii. 952 ; iv. 1121. vessels and nerves of the tonsils, iii. 953. Amygdaloid fossa, iv. 1121. An&ma, or Guinea-pig, anatomy of the, iv. 372, etseq. Anosmia (in morbid anatomy), ii. 825. causes and effects of, i. 416. giddiness of anemic patients, iii. 723 C. mode of treatment for, iii. 723 C. of the brain, iii. 720 C. characters of anaemic urine, iv. 1289. Anesthesia, or absence of sensation, iv. 1182. causes, iv. 1182. epidemie de Paris, iv. 1183. Anesthetic agents, iv. 1182. ether, chloroform, &c., iv. 1182, 1183. effects of the inhalation of, iv. 697. Anabas scandens, or climbing perch, conformation of the, iii. 986. Anal region. See ANUS. organs of insects, ii. 975. See INSECT*. Analgesia. See An. modification— ages, i. 123. cessation of action (death), i. 123. comparison of animals and vegetables, i. 124. general physical qualities and material or chemical composition, i. 124. organic composition (textures), i. 125. vital manifestations or actions of vegetables and animals (generally), i. 127. origin, i. 129. nutrition, i. 130. digestion, i. 132. respiration,!. 132. circulation, i. 133. secretions, i. 135. beat, L 136. light, i. 136. electricity, i. 137. motion and sensation, i, 137. comparison of animals with one another, i. 139. physical qualities and material constitution of animals, i. 139. size, i. 139. form, i. 139. structure, i. 140. actions of animals, i. 141. absorption,!. 142. circulation, i. 143. assimilation, i. 144. sensibility,}. 144. locomotion, i. 145. reproduction, i. 145. ANIMAL KINGDOM, i. 107. Divisions. — First Sub-kingdom. 1. Polygastrica, i. 108. 2. Porifera, i. 108. 3. Polypifera, i. \Q*. 4. Acalepha?, i. 108. 5. Echinodermata, i. 109. Second Sub-kingdom. 6. Entozoa, i. 109. 7. Rotifera, i. 109. 8. Cirrhopoda, i. 110. 9. Annelida, i. 1 10. 10. Myriapoda, i. 110. 11. Insecta, i. 110. 12. Arachnida, i. 111. 13. Crustacea, i. 111. Third Sub-kingdom. 14. Tunicata, i. 112. 15. Conchifera, i. 112. 16. Gasteropoda, i. 112. 17- Pteropoda, i. 113. 18. Cephalopoda, i. 114. 19 Pisces, i. 114. Supp. ANIMAL KINGDOM —continued. 20. Amphibia, i. 115. 21. Reptilia, i. 115. 22. Aves, i. 116. 23. Mammalia, i. 117. Summary, i. 117. See also under their various headings. Animal and vegetable kingdoms, relations existing be- tween as regards the function of reproduction, s. 256. Animal compounds used as food, ii. 13. dynamics. See MOTION, ANIMAL. food, s. 389. See Food. force, manner in which it is estimated, iii. 480. life, i. 263. light. See LUMINOUSNESS, ANIMAL. motion. See MOTION, ANIMAL. nuclei of intestinal calculi, iv. 84. Animalcules, theory of the first origin of, ii. 430. mode of generation of some, ii. 407. See GENERATION, ORGANS OF. confervoid,iii.532. microscopic, iv. 2. See POLYGASTRIA. See also ENTOZOA. Animating principle, doctrine of the. See LIFE. Animation, suspended, power of enduring in various animals, iii. 35. this power a measure of irritability, iii. 35. Anisoptera, or Ephemeridas ( May-flies), a section of insects of the order Neuroptera, ii. 864. characters of the section, ii. 864. ANKLE, JOINT OF Ttffc, i. 51. bones, i. 151. ligaments, i. 152. mechanism and function of the ankle-joint, i. 153. wrist-joint and ankle-joint contrasted, i. 154. ANKLE-JOINT, ABNORMAL CONDITION op THE, i. 154. accidents affecting the tendons, i. 154. ligaments, i. 154. bones, i. 155. luxation of the tibia inwards, i. 155. complete luxation of the tibia inwards complicated with a simple fracture of the fibula, i. 156. luxation of the tibia outwards, complicated with a simple fracture of one or both of the malleoli, i. luxation of the tibia and fibula forwards, and also luxation of these bones backwards from the ar- ticular pulley of the astragalus without fracture, complete luxation of the tibia forwards from the articular part of the astragalus, complicated with a simple fracture of the fibula, i. 159. partial luxation of the tibia forwards, with simple fracture of one or both of the malleoli, i. 160. partial luxation forwards of the tibia at the ex- ternal ankle, with fracture of the fibula at the malleolus, L 161. luxation of the bones backwards at the ankle-joint i. 162. morbid anatomy, i. 162. acute inflammation of the synovial membrane, i. 162. chronic disease, i. 163. ANKLE, REGION OF THE, i. 147. fascia, i. 148. lymphatics, i. 151. muscles, i. 150. nerves, i. 151. skin, i. 147. subcutaneous cellular tissue, i. 148. tendons, i. 149. veins, i. 151. ANNELIDA, a class'of Invertebrated Animals, i. 110. 161. 245. circulation, i. 169. 650. digestion, organs of, i. 168 ; iv. 446 j s. 297. divisions of the class, i. 165. external conformation, i. 166. generation,!. 171. Jj.411- 432. muscular system, iii. 538. nervous system, i. 168 ; iii. 607. luminous power of some. iii. 198. reproduction, i, 172 ; s. 132. spermatozoa in, s. 496. respiration, i. 170. structure of integuments of, s.48">. sensation, i. 167. mode of progression of, iii. 441 . Annelida errantia, i. 16o. genera of, i. 165. Annelida suctoria, i. 166. genera of, i. 166. Annelida terricola, i. 166. genera of, i. 166. Annelida tubicpla, i. 165. genera of, i. 165. Annular or orbicular ligament, ii. 505. 524 ; iv. 229. ligament of the base of the stapes, ii. 548. Annular protuberance, or pons Varolii, iii. 685. Annulala, ova of, s. [117]. Annulus columna? foraminis ovalis, seu isthmus Vieugseui, ii. 580. 3c 746 GENERAL INDEX. Anodonta, ova of, s. [109], [110]. Anomalies of the course of the aorta, i. 190. venous, i. 15, 16. Anomalus muscle, iii. 729. Anommatus terricola, absence of eyes in the, ii. 887. Anopisthia, a section of Polygastric Animals, iv. 5. Anoplotherium, anatomy of the. See PACHYDERMATA. Anorthopia, iv. 1462. common amongst negroes, iv. 1462. treatment, iv. 1462. Anoura, an order of Amphibia, i. 91, et seq. character of the order, i. 91 . anterior extremity in the, i. 94. metamorphosis of the, i. 106. See Frog ; Tadpole. Ant-eater (Mynnecophaga), its mode of taking its prey, iii. 8. See EDENTATA. Ant-eater of the Cape (Orycteropus), teeth of the, iv. 870. pelvis of the, s. 163, 164. Ant-lions (Myrtneleonidae), ii. 865. their mode of taking their prey, iii. 8. their mode of progression, iii. 442. Antclopidcz, a sub-order of Mammalian quadrupeds, s. 508. anatomical characters of, s. 508, et seq. organs of locomotion of the, iii. 454. speed of the, iii, 454. vocal organs and voice of the, iv. 1494. Antenrue considered as special organs of touch, iv. 1167. of Crustacea, i. 758. Antennce of insects, ii. 890. See INSECTA. functions of the antennas, ii. 892. Antcprostate,or Cowper's glands, iv. 1247. Antero-posterior arch of foot, ii. 344, 357. Ant/ielix, ii. 550, 551. Anthetidia of Cryptogamia and Phanerogamia, s. 232 — 253. Antheridium of red Algae, or Florideae, s. 221. See Algte; REPRODUCTION, VEGETABLE. of lichens, s. 230. functions of, s. 230. Anthoceros laevis, development of, s. 233. first period — from the germination of the spore, s. 233. development of the antheridia, s. 533. of the archegonia, s. 233. second period — fructification of the archegonia, s. 234. changes preparatory to the development of the spores, development of the spores, s. 234. Anthozoa, a sub-class of Polypifera, iv. 19. 24. characters of the sub-class, iv. 19. 24. digestive organs of, s. 296. ova of, s. [127.] Anthracotherinm, an extinct genus of Pachydermata, which see. Anthrax, i. 368 ; iv. 438. Antibrachial region, posterior, ii. 368. Antitragus, ii. 550, 551. Antlers of Ruminantia, s. 517. important changes co-existing with the shedding of the, in the solid-horned Ruminantia, s. 531. Antrum Hijrhmori, ii. 209 ; iii. 725. mannmillare, ii. 546. Ants (Formicidcc), habits of, ii. 865. fat of, ii. 235. provident ants, instincts of, iii. 12. nests of, in Siam, iii. 21. their economy and mode of proceeding, iii. 21, 22. torpidity of, during winter, iii. 12. tree, their nests, iii. 11. white (Termites), ii. 865. their singular habitations, iii. 11. Anuraa, a genus of loricated Rotifers, iv. 408. Anus (ostium recti, podex, culus), in anatomy generally, i. 173. muscles and fasciae, i. 175 ; s. 369. ischio-coccygasi muscles, i. 179. ischio-rectal spaces, i. 177. levatores ani, i. 178 ; iii. 394 ; s. 369. obturator fascia, i. 177. sphincter ani externus, i. 176 ; s. 369. sphincter ani internus, i. 176 ; s. 369. transversi perinaei muscles, i. 177. rectum, i. 175. 179. abnormal condition of the anus and neighbouring parts, i. 61. 182. atresia ani, iv. 969. cancer, i. 183. congenital malformations, i. 182. artificial anus, i. 182. contraction, i. 185. excrescences, i. 184. fissure, i. 185. fistula in ano, i. 186. haemorrhoids, i. 185. inflammation at the verge of the anus, i. 61. morbid conditions, i. 183. prol.ipsus ani, i. 184. Anus, abnormal condition — continued. syphilis, i. 183. imperforate anus, cases of, in the foetus in utoro, ii. 336. artificial, formation of, in cases of hernia, ii. 747 — 750. circumstances connected with the healing of an ar- tificial anus, ii. 750. Anvil-bone, or incus, ii. 546. development, ii. 5(iO. abnormal conditions, ii. 561. AORTA, i. 11. 187- 220; ii. 3. arch of the, i. 188. abdominal aorta, i. 189. anomalies, i. 190. branches, i. 192. I. branches arising from the arch, i. 192. right anterior or inferior coronary artery, i. 192. left superior or posterior coronary artery, i. 192. II. branches of the thoracic aorta-, right bronchial artery, i. 193. left bronchial artery, i. 193. ojsophageal arteries, i. 193. posterior mediastinal arteries, i. 193. inferior or aortic intercostal arteries, i. 193. anastomoses, i. 194. III. branches of the abdominal aorta, i. 191. phrenic arteries, i. 194. cceliac artery, i. 194. coronary artery of the stomach, i. 194. hepatic artery, i. 194. splenic artery, i. 195. superior mesenteric artery, i. 195. arteries of the small intestines, i. 195. colic arteries, i. 195. right superior colic or colica media artery, i. 196. ileo-colic, ccecal, or inferior right colic artery, i. 196. inferior mesenteric artery, i. 196. middle left colic artery, i. 19(3. lumbar arteries, i. 196". middle sacral artery, i. 197. sinuses, lesser, of the aorta, i. 189. development, i. 190. thoracic aorta, i. 18'.) ; s 428. diseased conditions, i. 191. 235; iii. 584. Aortic plexus of nerves, iv. 982 ; s. 429. Apes, iv* 195, et seq. See QUADRUM AN \. conformation of, compared with that of man, iv. 1295, et seq. Aphaniptera, an order of Insecta, ii. 8G7. characters of the order, ii. 867. Aphides, or plant lice, ii. 865. 868. mode of generation of, ii. 416. 468 ; s. 33— 3S. Dr. Waldo's observations on the origin and mode of formation of the repeated broods or colonies of aphides, s. [113], [114]., associations of, ii;. 17. Aphonia preceding or attendant on phthisis, iii. 123. from exposure to cold or damp, iii. 123. a symptom of tubercular consumption, iii. 119. treatment of, iii. 123. Aphrodita aculeata, or sea-mouse, description of the, i. 617. nervous system of the, i. 168; iii. 607, 608. muscles of the, iii. 538. Aphlhous ulceration of the tongue, iv. 1155. Apices of the lungs, s . 258. ApidfE, or humble and hive-bees, ii. 865. food of, ii. 865. Aplidium, or Alcyonium, a genus of Tunicata, iv. 1189, characters of the genus, iv. 1189. Apfysia, nervous system of the, iii. 606. Apoda, an order of Amphibia, i. 91. characters of the order, i. 91. Apode larvae of insects, mode of locomotion of the, iii. 441. Apodemata, i. 754. 757. Aponeuroses, or aponeurotic fasciae, ii. 231. See also FASCIA. those connected with muscular fibres, ii. 231. those which cover soft parts in particular regions, ii. 231. simple lamellae of fibrous membrane, ii. 231. power of resistance, ii. 231. Aponeurosis, abdominal, i. 4*. of the leg, iii. 130. of the anterior region, iii. 130. of the posterior region, iii. 130. superficial layer, iii. 130. deep layer, iii. 130. of the hand, dorsal, ii. 524. 528. palmar, ii. 527. Aponeurosis, cephalo-pharyngeal, iii. 945. cranial, i. 748. of elbow, region of, ii. 64. epicranial, i. 748. Annulosa, structure of the integument of, s. 485. GENERAL INDEX. 747 Aponcuroiiis — continued. of external oblique, ii. 840. of foot, ii. 352. of the fore-arm, ii. 362. of internal oblique, ii. 840. psoo-iliac, ii. 838. of supra-spinal division of scapular region, iv. 434. temporal, i. 729. of transversalis, ii. 840. Ap.nu-urotic septa, i. 217. Apoplexie fo droyante, 1. 795. 797. Apoplexy, causes of, i. 232. 416. capillary, iii. 720 D. causes of, iii. 720 D. cerebral — parts of the brain in which apoplectic effusions most frequently occur, iii. 7'20 L). appearances presented by the brain in cases of, iii. 7->0 D. common form of, i. 797. death by, i. 264. meningeal, cause of, iii. 716. spinal, cause of, iii. 713. Apothecia of lichens, s. 227. Apparatus ligament sus cavitatis sinuosae, ii. 343. Appendices epiploicae, i. 57 ; iii. 943; s. 366. use, s. 3C6. Appendix, vermiform, structure of, s. 365. uses of, s. 365. development of the, s. 402. xiphoid, or eusiform cartilage, iv. 1023. ossification of the, iv. 1024. Appetite, state of the, in cases of phthisis laryngea, iii. 121. Apple of Adnm, iii. 102. 112. 573. physiognomical character of, iii. 573. Aprost'erni, a tribe t>f Insects, ii. 861. characters of the tribe, ii. 86J. Aptera, an order of Insecta, ii. 86S. characters of the order, ii. 868. Aptcryr, pelvis of the, s. 168. Aqua Morgagni, ii. 200. Aquatic birds, mode of progression of the, iii. 438. Aquatica, a section of Insects of the order Hemiptera, ii. 86$. Aqu&ductus cochlea?, i. 734 ; ii. 533. 536. Aqiiecductus Sylvii, iii. 67fi. 693. 698. Aquseductus vestbuli, i. 733 ; ii. 533. 536. membraneous cavity of, ii. 536. Aqueduct of Fallopius, ii. 540; iv. 546. development of, ii. 559. Aqueous humour of the eye, ii. 201. source of the fluid, ii. 202. Aqttula Cotunnii, ii. 536. labyrinthi membranacei, ii. 539- Arabia, circumcision of females in, ii. 6^6. Arabs, complexion of, in various parts of Arabia, iv. 1333. of Algiers, characters of the, iv. 1357. ARACHMDA (a class of Invertebrate Animals), i. 111. 198. 246. apparatus for secreting the irritating or poisonous fluid, i. 208. apparatus for secreting the fluid which concretes in the air, i. 209. circulating system, i. 206. 652. digestive system, i. 1, 202; iv. 232; s. 298. divisions of the class, i. 198. external covering or tegumentary system, i. 201. fatty matter in the epiploon, uses of, i. 204. generative system, 1. 209; ii. 417. spermatozoa of, iv. 490. female generative svsteni, i. 21 1 . ova of Arachnida, s. [114.] formation of ova, s. [114.] arous, s. [1 >vi ova, i. 211. almost all oviparous", s. ['115}. copulation, oviposition, and development of the exclusion or hatching of the spider, i. 214. locomotion, organs and mode of, iii. 544. metamorphoses, i. 215. muscular system, iii. 539. n.-rvous system, i. 206; iii. 609. reproduction of the extremities, i. 215. secretion, organs of, i. 208. sense, organs of, i. 207. purposes served by, iii. 27. Arachnitis, or inflammation of the arachnoid membrane, iii. 636. Arachnoid cavity (arachnoid sac), effusions into the, iii. 716. Arachnoid membrane, iv. 523. abnormal anatomy of the arachnoid, iiL 716. acute inflammation, iii. 716. opaque condition of the arachnoid, iii. 716. causes of opacity, iii. 716. adhesion, iii. 716. deposits of bone or cartilage, iii. 716. effusions into the sub-arachnoid and arachnoid cavities, iii. 716. of serum, iii. 716. of blood, iii. 717. of pus, iii. 717. softening of the, iv. 708. Arachnoid, spinal, abnormal anatomy of the, iii. 713. inflammation, iii. 713. symptoms, iii. 713. cartilaginous spots, iii. 713. Aramanga, head and face of a youth of, iv. 1316. Araneidee, or spiders, i. 198. abdomen, i.20l. cephalo-thurax, i. 201. circulating system, i. 205. digestive system, i. 202; s. 299. external covering, or tegumentary organs, i. 201 . fatty globules in the abdomen, for consumption when in a torpid state, i. 204. generative system, i. 209. spermatozoa of, iv. 490. hatching and exclusion of the spider, i. 214. metamorphosis, i. 215. nervous system, i. 207. reproduction of the extremities, i. 215. respiratory system, i. 204. secretion, organs of, i. 208. apparatus for secreting the irritating or poisonous fluid, i. 208. apparatus for secreting the fluid which concretes in the air (spiders' webs), i. 209. sense, organs of, i. 207. subdivisions of the order into genera, table of, i. 199. See ARACHMDA. Arbor vitae cerebelli, lateral and median, iii. 692. Arcellinidce (capsule animalcules), a family of Polygastric Animals, iv. 4. characters of the family, iv. 4. Arch, crural, i. 5, note, 13; ii. 757. of the aorta, i. 188. of foot, antero-posterior, ii. 344. transverse, ii. 344. hyoid, iv. 1123. 1144. palatine, iii. 950. plantar, ii. 355. of urethra, iiu 925. of veins, superficial, iv. 1407. deep, iv. 1407. Archegnnia, development of the, in the higher Cryptogamia and Phanerogamia, s. 232 — 253. Arches of foot, construction of the, ii. 357. of pelvis, s. 139. tarsal or palpebral, iii. 93. Arciform process, or arciform fibres of medulla oblongata, iii. 680. Arctomys, or marmot, anatomy of the, iv. 370, el seq. Arcualum ligamentum, i. 11. Arcus interior of Senac and Haller, i. 11. senilis, or gerontotoxon, i. 80 ; ii. 178. Arenicola, or sandworm, organs of circulation in the, i. 650. Areola of nipple, iii. 247. change in colour of, after impregnation, iii. 247. vascularity of the, a sign of conception, ii. 457. See Conception; GENERATION. cuticle and cutis, iii. 217. tubercles of the areola, iii. 247. Areolar tissue generally, iii. 494 ; iv. 573. white fibrous element of, iii. 494. yellow fibrous element of, iii. 494. areolar tissue of the glands, iii. 494. muscles, iii. 576. scrotum, iv. 438. stomach, s. 325. subcutaneous, of the neck, iii. 566. of penis, iii. 912. subserous, diseases of, iv. 538. Argonaut, or paper-nautilus, mode of progression of the, i. 523 ; iii. 436. Aristotle, his opinion on the cause of vital phenomena, iii. 143. See LIFE. ARM (muscles of the), i. 219. biceps flexor cubiti, i. 219. brachiaeus anticus, i. 219. coraco-brachialis, i. 219. triceps extensor cubiti, i. 219. ARM (surgical anatomy of the), i. 216. amputations, i. 218. aponeurosis, i. 217. bones of, i. 216. development, i. 217. inflammation, i. 218. skin and subcutaneous tissue, i. 216. wounds, i. 218. Armadillo, the, ii. 47, et seq. See EDENTATA. pelvis of the, s. 163. Armenian language, iv. 1319. Arsenic, action of, on the vital power of the heart, 1. 723. 797. Arterial pulse, i. 663. number of pulsations occurring in a minute at different periods of life, i. 664. ARTERIES (normal anatomy), i. 220. absorbents in, i. 224. anastomoses, i. 221. branches of, i. 220, 221. circulation, arterial, phenomena of, i. 658. See CIR- CULATION. 3c 2 748 GENERAL INDEX. AKTERIES — continued. contractions of arteries, i. 6irds, s. 74. morphology of the bini's egg, as ascer- tained from its first origin and develop- ment, s. 75. heat, animal, of, ii. 649. 665. instincts guiding association of birds, iii. 18. guiding incubation, iii. 14. guiding migration, iii. 12 guiding modification, iii. 14. liver of birds, iii. 175. marsupium nigrum in, ii. 203. uses of the, ii. 204. myology, i. 290. climbing,!. 297. diving, i. 297. flight, 297. velocity of birds, iii. 429. powers of flight of birds, iii. 424. use of the tail in flight, iii. 429. See MOTION, ANIMAL. progression on land, i. 297 ; iii. 450. sailing, i. 297. swimming, i. 297. nervous system, i. 303 ; iii. 621. brain, i. 298. hearing, organ of, i. 308 ; ii. 536. lachrymal organs, i. 307. tas;e, organ of, i. 311. touch, organs of, i. 311. vision, organ of, i. 303. optic nerves of, iii. 764. chiasma of the optic nerves in birds, iii. 769. eyelids in, iii. 95. eyebrows and eyelashes of, iii. 95. secreting and derivative lachrymal apparatus in, iii. 98. ninth nerve, iii. 722. osteology, i. 270. 438. See also OSSEOUS SYSTEM. pelvis, s. 165. table of the number of toe phalanges in birds, i. 289. table of the number of vertebrae in birds, i. 272. pancreas of birds, s. 96. table of number of pancreatic ducts in several orders of birds, s. 97. peculiar secretions, i. 349. renal organ, iv. 233. respiratory organs, i. 341 ; iv. 331. 1021 ; s. 270. air-passages, i. 345. salivary glands, i. 316. supra-renal glands, i. 348. tegumentary system, i. 349. development of feathers, i. 351. thymus gland in, iv. 1097. thyroid glands, i. 348 ; iv. 1108. tongues of birds, iv. 1150. urinary organs, i. 347. urine of birds, iv. 1281. temporo-maxillan articulation in, iv. 941. vocal organs and voice of birds, iv. 1495, et seq. Aves aereae of Nitzsch, i. 266. altrices, a division of Birds, i. 266. aquaticae of Nitzsch, i. 266. aquatic birds, mode of progression of the, iii. 438. praecoces, a division of Birds, i. 26G. terrestres of Nitzsch, i. 2C6. AXILLA (surgical anatomy) i. 216, 217. 358. anterior wall, i. 359. inner wall, i. 360, 361. lymphatic glands, i. 362. posterior wall, i. 362. nerves, i. 361. wounds penetrating into the axilla, i. "62. dislocations of shoulder-joint downwards and inwards into the, iv. 6? 6 AXILLARY artery, i. 360. 363 j iv. 248. branches, i. 363. 1. acromial, i. 363. 2. superior thoracic, i. 364. 3. inferior thoracic, i. 364. 4. subscapular, i. 364. 5. posterior circumflex,!. 364. 6. anterior circumflex, i. 364. relations, i. 363. lesion of the axillary artery complicated with luxation of the head of the humerus, iv. 616. aneurism, i. 233. lymphatic glands, i. 368 ; iii. 231. nerve, iv. 759. plexus, ii. 361. vein, i. 360 ; iii. 249 ; iv. 407. Axiotoma Gaedii, i. 38. Axis of cochleae, ii. 531. cceliac, s. 325. Axis-cylinder of Rosenthal and Purkinjie, iii. 592. Azolotl, organs of respiration in the, i. 99 ; teeth of the, i. 95. Axungia articularis, secretion of, i. 253. Aye-aye of Madagascar (Cheiromys psilodactylus), iv. 221. anatomy of the, iv. 374, et seq. Azote, absorption and exhalation of, by the lungs, ii. 14'.). AZYGOS, the term, i 364. Azygos artery, iv. 64. ' tins of fishes, bones of, iii. 845. process of the sphenoid bone, i. 255. 726. vein, i. 365; iv. 1381. 1404. dorsal, i. 368. major, i. 305 ; iv. 1409. minor, or semi-azygos, i. 365 ; iv. 1409. superior, i. 306 ; iv. 1409. uvulae muscle, iii. 952. relations and uses, iii 952. B. Babyroussa, or horned hog, teeth of the, iii. 8G5. Baboontt iv. 197, et seq- See QUADRUMANA. BACK, REGION OF THE (surgical anatomy;, i. 3G7. cervical region, i. 367. dorsal region, i. 367. lumbar region, i. 367. diseases, i. 368. integuments, i. 367. lymphatics, i. 368. nerves, i. 368. subcutaneous cellular tissue, i. 367. BACK, MUSCLES OF THE, i. 368. first layer, i. 308. latissimus dorsi, i. 368. trapezius.i. 369. second layer, i. 370. levator anguli scapulae, i. 370. rhomboideus major, i. 370. minor, i. 370. third layer, i. 371 . serratus posticus inferior, i. 371. superior, i. 371. fourth layer, i. 372. splenius capitis, i. 371. colli or cervicis, i. 371. fifth layer, i. 371. cervicalis descendens, i. 372. complexus, i. 373. longissimus dorsi, i. 372. sacrp-lumbalis, i. 372. semi-spinalis dorsi, i. 372. spinalis dorsi, i. 372. trachelo-mastoideus, i. 373. transversalis colli, i. 373. sixth layer, i. 373. obliquus capitis inferior, or major, i. 373. superior, or minor, i. 373. rectus cupitis posticus major, i. 373. posticus minor, i. 374. spinalis, or semi-spinalis, colli, i. 373. fasciculi : inter-spinales, inter-transversales,and mul- tifidus spina?, i. 374. Badger-tribe (Melidae), dentition of the, iv. 913. BaUena. digestive organs of the, s. 304. Baltsnidcc, family of, i. 564. Balcenoptera rostrata, vocal organs and voice of, iv. 1494, 1495. Balaneus nucum, or maggot of the hazel-nut, mode of locomotion of the, iii. 441. Balanidea, a genus of Cirrhopoda, i. 684. See CIRRHOPODA. Bull and socket joint (Knarthrosis), i. 256. Bands, intercolumnal, i. 5. Bandicoots of Australia (Perameles), iii. 260. characters of the genus of bandicoots, iii. 260, 2G1. Bardbra,or Berberines, changes in their complexion from that of their ancestors, iv. 1336. " Barbadoes " leg, iv. 1014. Barbary, races inhabiting, characters of the, iv. 1357. Barking of dogs, peculiar to those which have been do- mesticated, iv. 1307. Barnacles, i. 683. See CIRRHOPODA. Barometric pressure, effect of, on the quantity of carbonic acid gas in the expired air, iv. 349. Bos -fond of the bladder, i. 379. Base of the cranium, i. 725. Basidiospores of fungi, s. 224. Basidium, mode of reproduction of the fungi by the, s. 232. Baailar artery, iii. 674. 678. 704 ; iv. 820. origin and relations, iv. 820, 821. branches, iv. 821. cerebellar artery, inferior, or posterior, iv. 821. superior, or anterior, iv. 821. aneurism of, i. 206. Basilar bone of Scemmerring, i. 726. 733. process, i. 732. of the occipital bone, i. 726. sinuses, i. 727. 732. sulci, i. 727. 732, Basilic vein, i. 216, 217. 360; ii. 63; 361, 362 ; iv. 1107. median, iv. 1407. Basio-glossus muscle, iv. 1133. Basi-vertobral veins of Breschat, iii. 630. Bass singing, iv. 1479. Bathiergut capensis, or white spotted orycte.-us, iv. 389- GENERAL INDEX. 753 Bnthiergus maritimus, or Cape mole, anatomy of the, iv. 369, et seq. Batrachia, a class of Vertebrated Animals. See AMPHI- BIA. ciliary motion in, i. 628— 63''. digestive organs of, s. 301. lungs of, s. v-82. effects of slightly elevated temperature on, iii. 36. ova of, s. 51. [9L] structure of the ripe ovarian ovum, s. [91.1 embryonic development, s. [93.] yolk-substance, s. [93.] germinal vesicle, s. [03.] vitelliue membrane, s. [94 ] formation of the ovum, and changes in its progress, pancreas of Batrachia, s. 91. pelvis of, s. 171. teeth of, iv. 885. tliymus gland of, iv. 1098. thyroid gland in, iv. 1109. tongue of, iv. 1146. vocal organs and voice of, iv. 1502. Bats, i. 594. See CHEIROPTERA. hibernation of the, ii. 704. See HIBERNATION. organs and mode of locomotion on land, iii. 455. pelvis of, s. l'J4. of the ternate bat, s. 1G4. wings and powers of flight of the, iii. 430. extreme sensibility to touch in the wings of the bat.iv. 1182. Bear, dentition of the, iv. 908. organs of voice of the, iv. 1489. Beaver (Castor fiber), anatomy of the, iv. 370, et seq. its mode of constructing its habitations, hi. 10, 11. digestive organs of the, s. 303. organs of voice of the, iv. 14 .2. urine of the, iv. 1280. \Veberian organ in the, iv. 1419. 1428. Beef fat, chemical characters of, ii. 233. Bees (Apidae), ii. 8G5. food of humble and hive-bees, ii. 865. sting of, lateral view of the, ii. 992. wings of, iii. 423. powers of fl ght of bees, iii. 423. precision of the straight line in which they return home, iii. 423. mode used by collectors of honey to discover bees' nests, iii. 423. hive-bees, instincts of, iii. 18. in the construction of their hives, iii. 18. in their out-door operations, iii. 19. in feeding their young, iii. 19 in their devotion to their queen, iii. 19. deviations of the instincts of bees, and their ac- commodation to circumstances, iii. 19. murder of the drones on the approach of winter, iii. 20. humble (Bombus terrestris). thoracic spiracle of the, iv. 1505. Beet-root, considered as an article of food, s. 395. composition of beet-root, s. 395 Beetles, ii. 859. characters of, ii. 859. tribes and suo-tribes of, ii. 859, 860. various species of, ii. 859—863. association of the males of Hoplia argentea, iii. 16. instance of mental operations in the proceedings of one, iii. 21. mode ot flight of the, iii. 421. nervous system of the, iii. 610. Belching, or simple eructation, s. 316. causes, s. 316. Belemnites, or thunder-stones, i. 520. belladonna, use of, in case of muscular disturbance, iii. 721. H. Berber races, characters of the, iv. 1357. Kerberines. See Bardbra. Beroe pileus, i. 1' 9; iii. 533. organs of locomotion '.of, i. 33. mode of progression of, iii. 433. question whether it has nervous filaments or not, iii. (502. structure of the integuments of, s. 485. Bezoar stones, formation of, in the stomach of the chamois, s. 538. Biceps lemoris muscle, iv. 61. flexor cubiti muscle, i. 216, 217. 359 ; ii. 63. 103. 264. 363 ; iv. 575, 756. flexor cruris vel femoris muscle, iii. 44 : iv. 1118; s. 137. Bicipital groove of humerus, ii. 159. tuberosity, or tubercle of the radius, ii. 1G3. Bicorne ligamentum, i. 3GO. Bicuspid, or mitral, valve of left ventricle, ii. 583. BILE, i. 127.374. method of analysing, iii. 811. analyses of, i. 374, 37.0. hile of Vertebrata and Invertebrata, iii. 176. biliary calculi, or gall-stones, i. 376. analysis of, iv. 85. See also Calculi, Biliary. BILE — continued. colouring matter of bile nearly identical with certain normal elements of the blood, iv. 460. expulsion of the bile, iii. 180. quantity secreted, iii. 180. secretion of bile, iii. 178. anomalous opening of the portal vein into the vena cava, iii. 178. effects of the suppression of the excretion of bile, ii. 150. metastasis of, iv. 462. uses of the bile, iii. 181. share taken by the, in the process of digestion s. 399. pathological anatomy of the liver — disorders of func- tion, iii. 194. alterations in chemical property of bile, iii. 195. alterations in physical properties of the bile, iii. 195. biliary calculi, iii. 195. entozoa, iii. 195. suppression of secretion of bile, iii. 195. biliary congestion, iii. 187. eflvcts of obstruction on the gall-ducts, iii. 187. biliary redundancy, cause of, i. 416. Biliary ducts, iii. 169." See Hepatic duct ; LIVER. plexus, lobular, iii. 498. 502; iv. 451. apparatus in various animals, iv. 445. Biliary system of Gasteropoda, ii. 388. See GASTERO- PODA. in Crustacea, i. 775. Bimanes, a genus of Saurians, iii. 543. Binoxide of protein, iv. 163. Bipapillaria, a genus of Tunicata, iv. 1188, et scq. characters of the genus, iv. 1188. Bird-lice (Nirmidae), ii. 868. Birds, fossil bones of, i. 289. fat of, chemical characters of, ii. 234. See AVESV Bishari, mental and physical characters of the, iv. 1356. Bitch, milk of the, iii. t'62. analysis of, iii. 362. Biventral lobe of cerebellum, iii. 689. 692. Blackbirds, their mode of walking, iii. 451. BLADDER (in anatomy generally), i. 376. BLADDER OF URINE (normal anatomy), i. 376. urinary bladder in man, i. 377 ; iii. 922. capacity, i. 378. media by which it is held in its position, i. 387. peritoneal investment, iii. 944. membranous laminae, or tunics, of, i. 380. 1. serous or peritoneal, i. 380. 2 mucous, i. 380. 3. muscular, i. 380. 4. deep cellular, i. 384. organisation of the bladder, i. 386. a. arteries, i. 386. b. veins, i. 386. c. lymphatics, i. 387. d. nerves, i. 387. regions of the bladder, i. 379 ; iii. 022. anterior region, i. 379. inferior region, i. 379. lateral regions, i.379. posterior region, i. 379. superior region, i. 379. trigone of the bladder, i. 385. shape of the bladder, L 377. uvula of the bladder, i. 385, 386. urinary bladder in other animals, i. 377. BLADDER, URINARY (abnormal anatomy), i. 389. congenital conditions, i. 3S9- of foetus in utero, ii. 335. absence, i. 389. extrophy, or extroversion, i. 391. 508 ; ii. 691. a cause of spurious hermaphroditism, ii. 691. congenital fissure of the, iv. 951. ectopia vesicae urinaria?, iv. 951. inversio vel prolapsus vesicae urinariae, iv. 952. numerical changes, i. 389. persistence of the urachus, i. 393. plurality, i. 390. septa, i. 390. acquired changes, i. 393. changes of capacity, i. 394. decrease, i. 394. increase, i. 395. fistulae, i. 398. fungous tumours, i. 401. % haemorrhage from the bladder, i. 401 . herniae, i. 395. idiopathic softening, i. 399. inflammation,!. 39(3. introversion, i. 395. paralysis, i. 402. rupture, i. 398. sacculi or cysts, i. 393. schirrus and cancer, i. 4'2. spasm, i. 403. varices, i. 402. symptoms of stone in the bladder, 721 H. tapping the bladder, iii. 923. operation of lithotomy, iii. 923. 754 GENERAL INDEX. Blapsid'i9. suppuration, i. 469, 470. structure, i. 469. subcutaneous or superficial bursae, i. 467. subcutaneous tissue, iv. 514. covering of the internal surface by a cell-growth, iv. 514. character of the cells, iv. 515. arrangement of the cells, iv. 515. GENERAL INDEX. 757 Bt K- i. MICOS.K - continued. subtendinous bursa?, iv. 51 «j. cartilage corpuscles, iv. 517. See also SYNOVIAL MEMBRANE. Biirsie mucuste around knee-j mt, iii. 48. synovia), of temporo-maxillary articulation, iv. 937. of the wrist, morbid condition of the, iv. 1528. /;'/5. physical and psychical characteristics of, iv. 13-12. proved to be a degraded caste of Hottentots, vi. 1343. peculiarity in the growth of the hair of the, iv. 1337. " size of the pelvis of a, s. 149. L'.-tttt'r. chemical properties of, iii. 359 ; s. 302. considered as an article of food, s. 392. quantity which may be consumed, s. 392. Butterflies, ii. 866. character* of, ii. 8C6. changes from the larva state into that of the perfect insect, ii. 874, et seq. mode of flight of the, iii. 421. common nettle-butterfly (Vanessa urticae), ii. 876. Bulyrin, method of determining the presence of, in organic substances, iii. 798. Jiuzzin» of insects, iv. 1504. Bftnu, the, of conchiferous Mollusca, described, i. 702. C. Cabbage, considered as an article of food, s. 395. composition of, s. 395. Cabrit, cranium of the, s. 519. Cachalot, teeth of, iv. 866. Caddis, or case-wcrms, ii. 865. Caducibranchiata, mode of locomotion of the, in water and on land, iii. 448. Ciccal artery, i. 196. Ctecuin, or blind gut, anatomy of the, s. 362. situation, s. 363. shape, s. 363. serous covering, s 363. mucous membrane, s.363. aperture of the caecum, s. 363. ileo-caecal valve, s. 363. development of the, s 402. Calogynus, or paca, anatomy of the, iv. 372, et scq. Ctenurus, mode of reproduction of, s. 26. CeEsarean operation, i. 9. Calamaries, or Teuthidae, i. 521. Calamus scriptorius of fourth ventricle, iii. 693. Calandria granaria, ii. 862. its ravages in granaries, ii. 862. Crrlnndria longipes, ii. 862. Calcaneal nerve, iv. 77 . superior and inferior, iv. 770. internal, iv. 770. Calcaneo-cuboid articulation, ii. 343. ligament internal, ii. 343. plantar, ii. 344. superior, or dorsal, ii. 343. Calcareous deposits in absorbent glands, iii. 233. in the carotid artery, i. 494. contained within the membranous labyrinth, — oto- lithi and otocoma, ii. 539. office of, in the function of hearing, ii. 567. in the ear of man, — otolithi and otoconia, ii. •'•39. See HEARING, ORGAN OF. shape in man and in the luwer animals, ii. 539. use of, ii. 539. Calcareous polypary of Polypi fera. See Polypi/era. Calcespongia, a group of Porifera, structure of, iv. 6G. Calculi, biliary calculi, iii. 195. varieties of biliary calculi, iii. 19"'. See Biliary calculi. in the bladder of the fcetus in utero, ii. 336. proximate analyses of various kinds of, iii. 805, 806. of prostate gland, iv. 159. urinary, iv. 1284. table of the relative frequency of the different kinds of urinary calculi in various countries, iv. 1284, 1285. lithic acid calculi, iv. 1287. mulberry, or oxalate of lime, calculi, iv. 1287. cystic oxide calculi, iv. 1287. phosphatic calculi, iv. 1287. alternating calculi, iv. 12S8. mixed or compound calculi, iv. 1288. vascular : phlebolites, phleboli'.hes, or vein-stones, iv. 1400. chemical analysis of, iv. 1400. origin and development of, iv. 1400. Calculous concretions in pancreatic duct, s. 1 12. in the gall-bladder, or ossified gall-bladder, iii. 183. in the urine, i. 394. C«//of the leg, formation of the, iii. 127. a characteristic peculiar to man, iii. 127. Calfs-favl jelly, ii. 404. Callldina, a genus of Rotit'era. iv. 407. Callithrix, a genus of Quadrumana, iv. 210, ct seq. Sec QUADRUMANA. characters of the genus, iv. 210. brain of, iii. 624. Cttllosuni, corpus, iii. 668. Callus, permanent, or osseous tissue produced for the reparation of injuries to bones, iv. 141. formation of, i. 444. See Adhesion of bones. Caloric, animal. See HFAT, ANIMAL. animal and vegetable, compare.:, i. 136. Calorific rays of light, iv. 1437. function of animals. See HEAT, ANIMAL. Calrana, i. 725. Ctili,ces of the kidney, iv. 238. Caiyciform papilla? of tongue, iv. 860. Cambala, a genus of Myriapoda, iii. 546, ct scq. Cambium, cephalic and thoracic, of the ova of Arach- nidans, i. 213. Camel, cervical vertebrae of the, s. 519. tongue of, s. 533, 534. cranii.m of, s. 513. dental formula of, s. 506. skeleton of, s. 507. stomach of, s. 302. water-cells of the stomach, s. 302. 507. 536. pelvis of the. s. 158. organs and mode of locomotion of the, iii. 451. pace at which it travels, iii. 454. urine of the, iv. 1280. Camelfon, vocal orgas of the, 1502. Camelidee, a sub-order of Mammalian quadrupeds, s. 506. anatomical characters of, s. 506—508, et seq. general character of the dermal envelope in, s. 531. Camelupardalis, s. 508. Camelus Bactrianus, vocal organs and voice of the, iv. 1494. Ctimera lucida, applied to the microscope for the purposes of micrometry, iii. 356. and for the purpose of delineating microscopic ob- jects, iii. 356. Campagnol, or short-tailed rat of France, iii. 17. Campanularia dichotoraa, i. 108. ova of, s. [127.] mode of reproduction of, s. 19. Camphor, composition of, iii. 152. Canada rat (Geomys bursarius), iv. 386. Canal, alimentary, basement membrane of the, iii. 487. of body of Fallopian tube, s. 600. carotid, i. 734. chorda? tympani, 556. central, in the spinal cord, is there a? iii. 655. Tiedeman on the canal of the spinal marrow, quoted, iii. 655. communis, ii. 531. crural, ii. 757. dental, inferior, ii. 214, 215. Eustachianus, i. 734. femoral, ii. 237. 240. incisive, ii. 20*. inferior maxillary, ii. 294. infra-orbital, ii. 208. inguinal, i. 7. 8. 12. lacrymo-nasal, ii. 208. malar, ii. 211. nasal, iii. 725. of Nuck, iii. 943 : s. 706. osseous, for nasal duct, iii. 90. anterior and outer walls, iii. 90. posterior wall, iii. 90. interior wall, iii. 91. palatine, anterior, ii. 2C8. palatinus tympani,ii.549. of Petit, ii. K,3. sacral, s. 118. semicircular, horizontal, ii. 531. posterior, ii. 531. superior, ii. 531. spinal, iii. 655; s. 119. spinosus, i. 736. tympanic, ii. 543, 544. V.dianus, i. 727. valvo-uterine, s. 706. See Vagina. Canals, cortical, ii. 487. 491. Haversian, iii. 849. hepatic venous, iii. 173. portal, iv. 1414. secreting, ii. 487, 48^. semicircular, development of the, ii. 558. function of th<>, fi. 569. 577. Canalicules, lachrymal, iii. 91. Canalwulus mastoideus of Arnold, li. 556. Canaries, their mode of walking, iii. 451. Cancer, or carcinoma, iv. 136. essential elements of, iv. 136. encephaloid cancer, iv. 137. schirrus, iv. \'.-T. colloid, iv. 137. chemistry of cancer, iv. 137. composition and structure, i. 756. of absorbent glands, 234. 758 GENERAL INDEX. Cancer — continued. affecting the membranes of the urinary bladder, i.402. of the breast, iii. 254. black cancer, or melanobis, iii. 256. cutaneous, iii. 254. origin and progress of the disease, iii. 251. operations for the removal of, iii. 255. scii rhus, or carcinoma, simplex, iii. 255. reticulare, iii. 225. alveolare, iii. 255. medullary, iii. 255. varieties of, iii. 256. fasciculatum, iii. 256. of the intestinal canal, s. 420. of the stomach, s. 421,422. of the brain, iii. 720 E. seat of the disease, iii. 720 E. origin and progress of the disease, iii. 720 E. fungoid and hard tumours of the brain, iii. 720 E. of the Fallopian tube, s. 620. of the kidney, iv. 263. of the liver, iii. 192. gelatiniform cancer, iii. 193. of the lower lip, iii. 954. of the lung, s. 293. of the ovary, s. 591 . colloid, s. 591. medullary, s. 593. scin hous, s. 593. of the pharynx, iii. 954. of the prostate gland, iv. 157. of the rectum, i. 184. scroti, or chimney-sweeper's cancer, i. 184 ; iv. 1014. of the serous membranes, iv. 537. ofthe spinal cord, iii. 715. of the testicle, encephaloid, iv. 1009. colloid, iv. 1010. melanosis, iv. 10,0. ofthe tongue, iv. 1157. ofthe uterus, s. 698. epithelial, s. 700. of vagina, s. 708. Cancer cursus, or land crab, velocity of the, iii. 444. Cancerous disease, effect of, on the neighbouring bones, i. 463. Cancroid of the uterus, s. 700. Cancrum or is, iii. 954. Canine fossa, ii. 207, 208. muscle, ii. 221. relations and action, ii. 224, 225. ridge, ii. 207. Cam's familiaris, organs of voice of the, iv. 1490. dentition of the, iv. 907. 909. Cannabis Indica, narcotic effects of, iv. 690. Cannon-shot wounds of arteries, i. 227. Cantharida;, or oil-beetles and blister-flies, ii. 863. Canthi of eyelids, iii. 79. Cape ant-eater, pelvis of the, s. 163. 164. Cape jerboa, or jumping hare (Helamys), anatomy of the, iv. 372, et seq. Cape mole ( Bathiergus maritimus ), anatomy of the, iv. 369, et seq. Capillaries of the mucous system, iii. 492. of muscle?, iii. 516. ofthe stomach, s. 327. Capillary vessels, i. 220, 221. structure of the, i. 669. capillary circulation, phenomena of, i. 669. properties of the capillary vessels, and their influence on the circulation, i. 671. stagnation of venous blood in the capillaries of the lungs, i. 673. theories of the capillary circulation, i. 673 ; iv. 1390. See also CIRCULATION. Capillary apoplexy, iii. 720 D. causes of, iii. 720 D. plexus, iv. 1107. Capitula Santorini, or cornicula laryngis, iii. 102. Capitulum costae, iv. 1026. Capra, anatomical characters of, s. 508, ct seq. Ctipron/ysof Cuba, singular liver of, iii. 175. Capromys, anatomy of the, iv. 372, et seq. Capsicum considered as an article of food, s. 395. Capsulce suprarenales seu atrabiliariae. See SUPRA-RENAL CAPSULES. functions ofthe, iv. 445. Capsular ligaments, i. 251 ; ii. 264. 778 ; iv. '71. of shoulder-joint, i. 359. of knee, iii. 46. Capsule of Glisson, i 504 ; iii. 166. vaginal portion, iii. 167. interlobular portion, iii. 167. lobular portion, iii. 167. of the kidney, iv. 238. ofthe lens ofthe eye, ii. 199. enveloping the prostate gland, iii. 933. Capsules, synovial, of knee, iii. 46. Cnput asperac asteriae, iii. ICO. Caput gallinaginis, iv. 1246. 1252. structure of, iv. 1252. Capybara (Hydrochcerus), anatomy of the, iv. 373 et seq. Carabus monilis, or ground-beetle, ii. 859. Carapace of Crustacea, i. 756. composition and structure, i. 756. arch-formed, of the turtle, uses of the, iii. 450. Caravels, i. 45. See ACALEPHTE. Carbon of vegetables, respiration of, i. 133. Carbonate of lime calculus, iv. 80. analysis of, iii. 806. deposit of, in urine, in disease, iv. 1283. Carbonate of magnesia calculus, iv. 81. Carbonaceous deposits of absorbent glands, iii. 233. Carbonic acid, the first product of animal decay, iv. 456. exhaled from the lungs, ii. 149. source and cause of the formation of, in the lungs, ii. 149. method of discovering the presence of, in organic sub- stances, iii. 802. proportions of, in the atmosphere in a pure and in a vitiated state, iv. 326. effect of, on the epiglottis, iii. 123. 125. Carcinoma of breast, alveolare, iii. 255. fasciculatum, iii. 256. medullary, iii. 255. varieties, iii. 256. reticulare, iii. 255. simplex, iii. 255. of the liver, iii. 192. seat of origin of carcinoma, iii. 194. of pancreas, s. 111. o! parotid glands, iv. 430. scroti, iv. 1015. of the teslicle, iv. 1009. scirrhous, iv. 1009. encephaloid cancer, iv. 1009. colloid cancer, iv. 1010. melanosis, iv. 1010. of thyroid gland, iv. 1116. Carcinowaious tumours of the liver, iii. 192. Cardia, or ccsophageal opening of the stomach, s. 308. action ofthe, iii. 721 L. uses of, indigestion, ii. 10. Cardiac arteries, i. 192. nerves, ii. 595 ; iii. 722. 887. 896. 902. nerve, inferior, ii. 595 ; s. 425. left, ii. 595. middle, ii. 595. left.ii. 596. superior, ii. 595 ; s. 424. first, ii. 851. plexus, great, ii. 596 ; s. 427. pouch, or great or splenic extremity, s. 308. vein, great, iv. 1414. posterior, iv. 1415. Cardinal teeth of Conchifera, i. 709. Cat 'dilfs, ii. 636; iv. 707. anatomical characters of, ii. 636. Caries, articular, ofthe shoulder-joint, iv. 581. of the bones ofthe face, ii. 220. of ihe cranium, i. 746. arising from a scrofulous cause, i. 450. from syphilis, i. 450. ofthe spine, i. 451. scrofulous caries, i. 451. Cardium (cockle), nervous system of the, iii. 604. CARNIVORA (a group of Mammiferous Animals), i. 470. chylife.rous system, i. 479. mesenteric glands, or pancreas Asellii, i. 479. thoracic duct, i. 479. circulation, organs of, i. 479. digestive organs, i. 477 ; s. 302. compared with those ofthe Ruminantia, i. 479. gall-bladder, i. 479. hepatic ducts, i. 479. liver, i. 479. pancreas, i. 479 ; s. 97. spleen, i. 479. stomach and intestine, i. 478. teeth, i. 478; iv. 910. generative system, i."482. male organs, i. 482. female organs, i. 482. locomotive organs, iii. 455. muscular system, i. 477. nervous system, i. 480. organ of hearing, i. 480. of sight, i. 480. lacrymal glands, i. 480. of smell, i. 481. of taste, i. 481. respiration, organs of, i. 480. skeleton, i. 471. anterior extremity, i. 472. carpus, i. 476. cranium, i. 472. frontal bones, i. 473. inferior maxillary, i. 471. intermaxillary, i. 474. lacrymal bone, i. 474. malar bone, i. 474. nasal bones, i. 474. occipital bones, i. 473. parietal bones, i. 473. sphenoid bone, i. 474. GENERAL INDEX. 759 CAHNIVORA, anterior extremity — emttwaf. cranium, temporal bones, i. 473. forearm, L 476. humerus, i. 476. im-tacarpal bones, i. 476. rib.s, i. 475. sacrum, i. 475. shoulder, i. -175. acromion process, i. 17'J. clavicle, i. 476. coracoid process, i. 476. scapula, i. 475. sternum, i. 475. vertebral column, J. 474. cervical vertebrae, i. -171. coccygeal, i. 475. dorsal, i. 475. lumbar, i. 475. posterior extremity, i. 476. femur, i. 476. metatai sal bones, i. 477. pelvis, i. 470. tibia and fibula, i. 476. toes, i. 477. secretions, i. 481. follicles producing peculiar secretions, i. 481, 482. urine, i. 4M. Carotid nerve, ii. 555 ; iii. 887. L1 A norm ARTERY, i. 220, 482; iii. 704. anastomoses of, i. 493. Primitive carotid, i. 483. bifurcations, i. 484. relations of the trunk to the primitive carotid, i. 483. anteriorly, i. 483. externally, i. 484. internally, i. 484. posteriorly, i. 483. varieties to which the organs of the carotid arteries are subject, i.484. External carotid ; i. 484 ; iii. 93. 903. branches, i. 485; iii. 'J3. anterior branches, i. 485. 1. thyroid, superior, i. 485. branches, i. 485. a. hyoidean branch, i. 485. b. superficial, i. 485. c. laryngeal, i. 485 j iii. 110. 2. lingual, i. 4N5. branches, i. 485. a. hyoidean, i. 486. b. dorsalis linguis, i. 486. c. sublingual, i. 4H6. d. ranine, i. 486. 3. K.bial, or facial, i. 486. branches, i. 486. a. inferior palatine, i. 486. b. submental, i. 486. c. inferior labial coronary, i- 4*6. d. superior labial coronary, i. 487. e. laterales nasi, i. 487. /. dorsales nasi, i. 487. irregularities of the labial, or facial artery, i. 487. internal branch of the external carotid, or in- ferior pharyngeal artery, i. 487. proper pharyngeal, i. 487. posterior meningeal, i. 487. posterior branches, i. 487. 1. occipital artery, i. 487. 2. posterior auris, or aui icularis posterior, i. 488. superior and terminal branches, i. 488. 1. temporal artery, i. 488. transversalis faciei branch, i. 488. middle temporal branch, i. 488. 2. internal maxillary, i. 489. branches, i. 489. a. middle meninpeal, i. 489. b. inferior maxillary or inferior dental, i. 489. c. posterior deep temporal, i.489. d. masseteric, i. 489. c. pterygoid arteries, i. 4S9. /. buccal artery, i. 489. g. anterior deep temporal, i. 469. h. alveolar, i. 490. t. infra-orbital, i. 490. /. superior palatine, i. 490. m. Vidian, i. 490. n. pterygo-palatine or superior pharyngeal, i. 490. o. spheno-palatine, i. 490. Internal carotid, i. 490 ; iii. 93. relations, i. 490. anteriorly, i. 490. posteriorly, i. 490. ophthalmic artery, i. 491. branches, i. 491. 1. lachrymal artery, i. 491. 2. central artery of the retina, i. 491. 3. supra-orbital, i. 491. CAROTID ARTERY, ophthalmic brandies— continued. 4. ciliary arteries, i.491. anterior, i.492. long, i. 491. short, i. 491. 5. muscular arteries, i. 492. inferior, i. 492. superior, i. 492. 6. posterior ethmoidal artery, i. 492. anterior ethmoidai, i. 402. 7. palpebral arteries, i. 492. inferior, i. 492. superior, i. 492. 8. frontal artery, i. 492. 9. nasal, i. 492. lateral or posterior communicating branch ot Willis, i. 492. choroid artery, i. 492. cerebral, anterior, i. 493. middle, i. 493. sheaths, iv. 820. surgical and morbid anatomy, i. 493 — 495. Carotid branch of sympathetic nerve, ii. 490. Carotid canal, i. 734 foramen, ii 734. branch of Vidian nerve, ii. 288. plexus of nerves, internal, s. 426. external, s. 4*26, Carp, teeth of, iii. 979. Carpal arteries, iv. 1506. articulations. See CARPUS. branch of radial artery, ii. 5'29. Carpi radialis artery, anterior, iv. 223. dorsalis, iv. 223. ulnaris posterior, iv. 225. anterior, iv. 225. Carpo-metacarpal ligaments of thumb, ii. 509. dorsal, ii. 509. palmar, ii. 509. articulations, ii. 509. joints, motions of the, ii. 5f9. of the thumb, ii. 509. Carpophaga, a tribe of Marsupialia, iii. 262, et scq. characters of the tribe, iii. 262. Carpus, or wrist bones, ii. 505 ; iv. 1506. annular ligaments of, ii. 505. 508. articulations of, ii. 505, 506. 508. motions of the, ii. 508. bones of, ii. 505. of first row, ii. 506. of second row, ii. 506. See HAND, BONES OF. structure and development of bones of the carpus, ii. 506. abnormal conditions of the, ii. 510. Carpus of Carnivora, i. 476. See CARNIVORA. Carrion beetles, ii. 860. Carrots, composition of, s. 395. considered as an article of food, s. 395. Curtilage of bone, i. 437. See BONE, NORMAL ANATOMY. CARTILAGE, i. 495. chemical composition, i. 498. elasticity of, ii. 58. divisions, i. 495. A. temporary, i. 495. B. permanent, i. 495, 496. I. articular, i. 247. 496.: iv. 522. forms of, i. 247—249. structure of, i. 247 250. See also ARTICULATION. uses of, i. 248. II. non-articular, i. 496. differences depending upon age, i. 496. elasticity, i. 496. structure, i. 496. organisation, i. 496. physical properties, i 496. C. accidental cartilage, i. 497. 1. insulated or loose, i. 4<»7. d. in joints, i. 497. See JOINTS. origin, i. 497. b in serous sacs, i. 497. 2. accidental cartilages of incrustation, i. 498. 3. irregular or amorphous masses, i. 498. pathological conditions, i. 499. inflammation, i. 499. ulceration, i. 429, 500. See also JOINT. primary, i. 499. secondary, i. 499, N)0. See also ARTICULATION ; FIBRO-CARTILAGE. Cartilage of the elbow-joint, disease of the, ii. 77. " Cartilages of incrustation," i. 248; iii. 45 ; iv. 573. See ARTICULATION. Cartilage, or Cartilages, in particular: — of acetabulum, ii. 777. adventitious, iv. 139. arytenoid, iii. 102. costal, iv. 1024. 1031. cricoid.iii. 101. cuneiform, iii. 101. diarthrodial, i. 255. 760 GENERAL INDEX. Cartilage — can/in ut if. eusiform, or xiphoid appendix, iv. 1023. ossification of the, iv. 1024. fibre-triangular, iv. 1506. fibrous and spongy, adventitious, formation of, iv. 142. of hip-joint, inflammation and ulccration of the, ii. 788. intervertehral, i. 250. of knee-joint, iii, 45. of larynx, iii. 100. diseased conditions of the, iii. 120. See LARYNX, morhid anatomy and pathology. loose, iv. 538. of the nose, iii. 726. superior, iii. 726. lateral, iii. 726. triangular, iii. 726. inferior or pinna!, iii. 726. structure, iii. 727. of the ribs, i. 249. sacro-iliac, s. 122. of Santorini, iii. 102. semilunar of knee-joint (cartilagines falcata? s. lu- natae), iii. 45. ses-'.mpid, iii. 727. softening of, iv. 712. tarsal, iii. 78. 81. ciliary, iii. 81. orbital, iii. 81. thyroid, iii. 101. of tibio-fibular articulations, iv. 1110. triangular of wrist-joint, i. 249. Cartilaginous deposits in the diaphragm, ii. 6. fibro-cartilaginous tissue, i. 127. patches in the coats of arteries, iv. 87. rings of the trachea, s. 261. tissue, elements of the, i. 127. Cartilaginous fishes. See PISCES. Caruncula lachrymalis, iii. 80. 84. calculi in the follicles of the, iv. 82. seminalis, iv. 1252. See Caput gallinaginis. Carunculte myrtiformes, s. 711. Cnrybdea marsupialis, organs of digestion of, i. 43. Cnryophyllia fasciculata, a genus of Pulypifera, iv. 37. Case-worms, or caddis, ii. 865. I Casein, or cheesy matter of milk. iii. 359 ; iv. 168. aposepedine, or caseous oxide, iii. 359. mode of obtaining, iii. 359. analysis of, iii. 798 ; iv. 162. proportion of, in various kinds of milk, iv. 168. mode of obtaining casein, iv. 168. vegetable casein, iv. 169. occurrence of, in combination with fat or " milky urine," iv. 94. Castor fiber (the beaver), anatomy of the, iv. 370, el seq. organs of voice of the, iv. H92. Castor cum, secretion of the drug, iv. 396. Castration, ii. 443. effects of, in the female, ii. 443. in the rriale, ii. 443. circumstances analogous in hermaphroditism, ii. 443. sexual desire not always entirely destroyed by castra- tion, ii. 443. in the lower animals, ii. 443. effect of, on the male, when performed some time before puberty, ii. 717, 718; iv. 985. effect of the removal of the testicles at or after the period of puberty, ii. 717, 718 ; iv. 985. on some of the lower animals, ii. 718. alleged wasting effect of castration on the cerebellum refuted, iii. 687. Cat, brain of the, iii. 696. nails of th", i 255. organs of voice of the, iv. 1490. powers 01 leaping of the. iii. 474. its love of the odour of Nepeta (cat-mint) and Vale- rian, iv. 702. Cnt, flying, mode of flight of the, iii. 430. Catalytic action common to organic and inorganic opera- tions, iii. 153. See LIFE. mode of operation, iii. 153. Catamenia, ii. 439, 440. See Menstruation. Catarrh of the bladder, i. 3!'9. " Catarrh of the dying," i. 80!. Catarrhus uteri, s. 694. Caterpillars, dormant vitality of, iii. 157. See INSECTA, larva of, Catodontida, family of, i. 564. Caucasian race, iv. 1328. principal characters of the, iv. 1348. capacity of skull of the, iii. 666. Cauda, or extremity, of the medulla oblongata, iii. 679. Cauda equina, the, iii. 650. 658; s. 119. Cauda lienis, iv. 771. Caudate lobule of liver, iii. 937. Caudate nerve-vesicles, iii. 647. Cauliflower excrescence of the uterus, s. 700. Cav& nares, or nares interna?, iii. 723. Cavernous body of penis. See Corpus cavernosum. plexus of nerves, s. 426. Cavia capybara, organs of voice of the, iv. 1491. cobaya, Weberian organ in, iv. 1418. Ccivia, or Guinea-pig, anatomy of the. iv. H7'2. ct scq, paca (the paca), anatomy of the, iv. 372, ct scq. Cavicornua, anatomy of, s. oOS. horns of, s. 518. Cavities of the face, ii. 217. See NOSE; OKBIT. CAVITY, in general, i. 500. definition, i. 500. abdominal cavity in particular, i. 500. epigastric region, i. 502. hypoaastric region, i 505. umbilical region, i. 504. abnormal conditions of the abdominal cavity, i. 507. congenital malformations of the abdominal pa- rietes. i. 508. morbid conditions of the abdominal parietes, i. 500. causes, i. 509. congenital malformation of the abdominal cavity, i. 509. See also ABDOMEN ; STOMACH AND INTESTINE. Cavity, in particular : — abdominal, i. 19. cotyloid, or acetabulum, s. 116. digital or ancyroid, or posterior cornu of lateral ven- tricle, iii. 674. or fossa trochanterica, ii. 1C6. glenoid, i. 219. 735; ii. 340; iv. 573. of radius, ii. 163. of scapula, ii. 157. of tibia, external, ii. 108. internal, ii. 1G8. nasal, iii. 723, 724. of the pelvis, s. 127. peritoneal, iii. 940. sigmoid, greater, ii. 66. 162. lesser, ii. 66. of the ulna, iv. 229. Cavity, thoracic. See THORAX. of the tympanum, ii. 543. 546 of the uterus, s. 627. See Uterus. Cavum sen sinus laryngis. See Rt'ma glottidis. Cavy of Patagonia (Chloromys Patagonica), anatomy ot the, iv. 384, ct seq. Cebince, or monkeys of the NewWorld, iv. 210, et seq. Cebus, a genus of Quadrumana , iv. 210, et scq. See QUA- DRUMANA. characters of the genus, iv. 210. Ceciliadcc, a family of Reptilia, iv. 265, et seq. O//-evoltition. See ADVENTITIOUS PRODUCTS, — blastemal formations. (W/-pigment, iv. 116. Cells of adventitious growths, iv. 119. form, size, and contents of, iv. 119. See PRODUCTS, ADVENTITIOUS Cells, development of, in the process of secretion, iv. 441. biliary or hepatic, in human liver and in that of various animals, iv. 452. or corpuscles of bones, iii. 850. See OSSEOUS SYSTEM. of tracheal epithelium, s. 260. Cellulte ethmoidales, i. 731. Cellular, deep, membranous lamina; of the urinary bladder. i. 384. CELLULAR TISSUE, i. 509. arrangement, i. 509. common cellular membrane, i. 510. penetrating, i. 510. special, i. 510. development, i. 512. properties, i. 511. theories, i. 511. structure and organisation, i. 511. bloodvessels and lymphatics, i. 511. chemical composition, i. 511. nerves, i. 511. morbid conditions of cellular tissue, i. 513. I. inflammation, i. 513. a. acute circumscribed inflammation, or phleg- mon, i. 513. 1. congestion of the bloodvessels, i. 513. 2. effusion, i. 513. 3. suppuration, i. 514. 4. ulceration, i. 514. 5. mortification, i. 514. b. chronic inflammation, i. 514. c. spreading or diffuse inflammation, i. 515. II. infiltration, or effusion, i. 515. a. blood, i. 515. b. serum, i. 515. c. air, i. 516. d. urine, i. 516. III. induration,!. 516; ii. 333; iv. 712. softening, iv. 712. IV. morbid growths, i. 516. V. foreign bodies, i. 516. See ADIPOSE TISSUE; VEIN. Cellular tissue, subcutaneous, i. 3*. of ankle, i. 148. of hand, ii. 524. of the eyelids, iii. 82. adventitious, iv. 140. Cellules of breasts, iii. 248. GENERAL INDEX. 7bl Celtic races, principal characters of the, iv. 1348. Cement of teeth (caMiuntum, crusta petrosa), iv. 864, 8G5. Ccn, indium fraugulae, ripe spores of, s. 227, 228. Cent pedes, iii. 545. nervous system of the, iii. 609. luminousness of some, iii. 198. Central artery, ii. 186. of the retina, iii. 786. Centres of Nervous actions. See NERVOUS CENTRES. Centripetal development, law of, i. 763. Centrum ovale majus (or of Vieusseus), iii. 674, 694. minus, iii. 674. fibres of the centrum ovale, iii. 723 B. tendincum, s. iierveum, s. phrenicum, ii. 2. Cephalic or radial vein, i. 21(5. 359, 360; it 63 ; iii. 249 : iv. 1407. median cephalic, ii. 361, 362 ; iv. J407. Ct'phalu-pharyngeal aponeurosis, iii. 94->. Ctrti \LOPODA (a class of Invertebrata), i. 114. 517. characters of the class, i. 114. 517. arms, i. 517. branchia?, i. 517. eyes, i. 517. head, i. 517. infundibulum, i. 517. mouth, i. 517. sexual organs, i. 517. circulation, organs of, i. 538. definition, i. 517. digestive system, i. 521. divisions of the class into orders, i. 517. Order I. Tetrabranchiata, i. 518. Order II. Dibranchiata, i. 519. subdivisions of the orders, i. 519. generative system, i. 519; ii. 418. ova of Cephalopoda, s. [105.] ova of Sepia officinalis, s. [105 ] spermatozoa in Cephalopoda, iv. 485. internal cartilaginous parts or endo-skeleton, i. 524. locomotive system, i. 525. organs of locomotion and mode of progression of the, iii. 436. 445. illustrated by the Octopus vulgaris, iii. 446. muscular system of, iii. 541. nervous system, i. 547. organs of sense, i. 551. of hearing, i. 554. of sight, i. 531 ; iii. 95. 774. of smell, i. 554. of taste, i. 554. of touch, i. 555. salivary glands of Cephalopoda, iv. 432. Cephalo-thorax of Arachnidans, i. 201 ; iii. 240. Cerambyx latipes, ii. 862. Ccra/o-glossus muscle, iv. 1133. C--ratvhyal process, iv. 1124. Cercaritc, seminal, ii. 112. See ENTOZOA. mode of reproduction of, s. 30. vegetable, ii. 112. Cercopithecus, a genus of Quadrumana, iv. 196, et seq. See QUADRUMAW. characters of the genus, iv. 196. Cerealia, the, considered as food, s. 393. constituents, s. 393. bread .393. Cercb liar Arteries, inferior, iii. 704 ; iv. 821. posterior, iii. 704, 705. superior, iii. 704; iv. 821. fibres, or restiform bodies, of the medulla oblongata, ui.cn. or posterior surface of the cranium, i. 733. Cerebellum, iii. 678. 687. arbor vita?, lateral and median, iii. 692. castration, alleged effects of, on, iii. 687. commissures, iii. 691. long and hidden, iii. 691. short and exposed, iii. 691. single, iii. G'.»l. corpus dentatum, or rhomb >ideum, iii. 6D2. crus cerebelli, iii. 674. 677. 685. 692. peduncles of, iii. 693. inferior, ii. 272 ; iii. 693. middle, iii. 693. superior, — processus cerebelli ad testes, or cerebro-cerebellar commissures, ii. 272 ; iii. 693. development of the cerebellum, iii. 625. 687. relative development of cerebellum to cerebrum in the adult, iii. 687. fissures, i. 73J ; iii. 6«7. horizontal, iii. 688. purse-like fissures, or posterior notch, iii. 688. semilunar, iii. 687. valley, iii. 687. laminae, iii. 689-691. lobes and lobules, iii. 689. amygdala, iii. 689. 692. biventral, iii. 689. 692. median, iii. 689- posterior, iii. 689. 692. pyramid of Reil, iii. 691. uses, iii. 691. Sup p. Cerebellum, lobes — continued. posterior superior lobe, iii. 689. 692. slender, iii. 689. 692. spigot of Reil, iii. 691, 692. uses, iii. 691. square lobe, iii. 689. 691. nodule, iii. 690. 693. processes, iii. 629. falx cerebelli, iii. 629. tentorium cerebelli, iii. 629. 673. 687. shape of the cerebellum, iii. 687. sections of the cerebellum, iii. 692. horizontal, iii. 692. vertical, iii. 692. size and weight of the cerebellum, iii. 687- subdivisions into median lobe and lateral lobes or hemispheres, iii. 687. surfaces, inferior, iii. 639 691. superior, iii. 689, 690. velum, posterior medullary, iii. 690. ventricle, fourth, iii. 693. aqueductus Sylvii, iii. 693. calamus scriptorius, iii. (J93. choroid plexuses of the fourth ventricle, iii. 693. vermiform process, iii. 687. inferior, iii. 687. superior, iii. 687. white and grey matter, iii. 692. microscopic anatomy of the cerebellum, iii. 709. functions of the cerebellum, iii. 722 Q. co-ordination of movements, iii. 722 R. Gall's views of the connexion of the cerebellum with the sexual functions, iii. 722 S. phrenological hypothesis of the cerebellum as the sensorium commune of sexual feeling, ii. 444; iv. 985. of man compared with that of the lower animals, iv. 1299. concretions of the cerebellum, iv. 90. comparative anatomy of cerebellum, iii. 687. Cerebral action, laws of, iii. 681. apoplexy, iii. 720 D. appearances presented in cases of, iii. 720 D. arteries, anterior, i. 493; iii. 704. middle, i. 493 ; iii. 704. posterior, iii. 704. convolutions, functions of the, iii. 722 X. fissure, great, of Bichat (transverse or horizontal of Cruveilhier), iii. 673. ophthalmic vein, iii. 91* sinuses, iv. 1374. or superior surface of the cranium, i. 733. veins, nerves of, iv. J382. Cerebric acid, iii. 587. Cerebrinc, in the composition of the blood, i. 411. Cerebro-cerebellar commissures, or processus cerebelli ad testes, iii. 693. Cercbro-spinal centre, iii. 650. See Cerebellum; Cere- brum ; Encephalon f Medulla oblongata ; Mesocephale; Spinal cord ; NERVOUS CEN IRES. Cerebro- spinal fluid, iii. 638. fluid in the cerebral ventricles, iii. 640. orifice of communication as described by Majendie, between the fourth ventricle and the sub-arachnoid space, iii. 640. estimate of the quantity of the sub-arachnoid fluid, iii. 641. manner of its secretion, iii. 643. physical and chemical properties of the cerebro-spinal fluid — analyses, iii. 643. use of the cerebro-spinal fluid, iii. 643. in reference to pathology, iii. 642. Cerebro-spinal nerve, structure of, compared with that of the striped muscle, iii. 593. nerves, connection between the sympathetic and the, s. 443. Cerebrum. See Encephalon. chemical composition of the, iii. 587. crura cerebri, iii. 673. locus niger of the crus cerebri, iii. 647. posterior artery of, iv. 821. processes, iii. 629. falx cerebrum, i. 729, 730; iii. 629. of man compared with that of the lower animals, iv. 1299. causes of the tendency to liquid effusions in infancy, iii. 588. cerebral concretions, iv. 90. hernia cerebri, iv. 141. of the foetus in utero, ii. 320. CERUMEN, i. 562 ; ii. 553. composition, i. 562. Ceruminous glands, ii. 553. Cervical artery, ascending, iv. 824. superficial, iv. 824. deep, iv. 824. profunda artery, i. 367- descendens muscle, i. 371. fascia, ii. 230. fossa, i. 367. ganglia, s. 423. supremum ganglion, ii. 554. 3 D 762 GENERAL INDEX. Cervical— continued. lymphatic glands, i. 368. linea alba, ii. 230. Cervical nerves, ii. 272. superior, ii. 272. posterior roots of, ii. 272. nerve, anterior, iii. 571. descending, internal, iv. 753. first, posterior branch, iv. 707. 748. 750. anterior branch, iv. 752. second, posterior branch, iv. 750. anterior branch, iv. 752. superficial (superficialis colli), origin of, iv. 753. ascending branch, iv. 753. descending branch, iv. 753. third, anterior branch, iv. 752. posterior branch, iy. 751. ascending branch, iv. 751. descending branch, iv. 752. horizontal branch, iv. 751. fourth, anterior branch, iv. 752. anterior branches of the four inferior, iv. 754. posterior root of, iv. 751. fifth, sixth, seventh, and eighth posterior branches, iv. 751. plexuses of nerves, i. 3G8. 748 ; ii. 555. posterior, iv. 751. C.'rvical vertebra of Carnivora, i. 474. See CARNIVORA. Cervico -facial nerve, iii. 904. Cervico -thoracic septum, iii. 570. CervidfS, a sub-order of Mammalian quadrupeds, s. 50S. anatomical characters of, s. 508, et seq. vocal organs and voice of the, iv. 1494. Cervix. See NECK. Cervix of the bladder, i. 387. Cervix of uterus, s. 625. structure and arrangement of the tissues composing the cervix, s. 638. muscular coat, s. 638. mucous coat; epithelium, s. 638. papillae, s. 639. mucous follicles, s. 640. arteries which supply (he cervix, s. 611. alterations in the form of the cervix during gestation, s. 645. 649. pathological conditions of the. See Uterus. Cervus Muntjac (the kijang or muntjak), s. 508. cranium of, s. 512. Cestoidea,an order of Entozoa of Rudolphi, ii. 116. See ENTOZOA ; Sterelmintha. digestive organs of the, s. 295. ova of Cestoidea, s. [124.] CETACEA(aclass of Mammiferous Vertebrate Animals), i. 562. bones of the, i. 438. circulation, organs of, i. 576. digestion, organs of, i. 571 ; s. 304. divisions, i. 563. generation, organs of, i. 591. male, i. 591. female, i. 592. motion, organs of, i. 564. nervous system, i. 582. organ of sight, i. 584. hearing, i. 586. taste, i. 589. touch, i. 589. respiration, organs of, i. 579. spermaceti, description of, i. 590. salivary glands of Cetacea, iv. 433. thymus gland of, iv. 1097. urinary organs, i. 581. Weberian organ in the, iv. 1419. Celine, chemical composition of, ii. 234. Cetoniidee, ii. 859. Ceylon. Albinoes of, i. 84. Chacrelas, or Albino, i. 86. Chcctodon rostratus, its mode of taking its prey, iii. 8. Chtetonotus, a genus of Rotifera, iv. 401, et seq. Chaffer-beetles (Melolonthidae), ii. 860. Chalay.ee of fowls' eggs, s. 64. Chalk, effect of large doses of, in producing intestinal cal- culi, iv. 84. ChamcEleonidtz, a family of Reptilia, iv. 2G5, et scq. Chameleon, anatomy of the, iv. 271, et seq. eyelids of the, iii. 95. its organs of locomotion and prehension, iii. 449, tongue of, iv. 1147, 1148 Chamois, formation of Bezoar stones in the stomach of the, s. 538. Chancre, co-existence of, with gonorrhoea, iv. 1258. incipient, treatment of, by lunar caustic, iv. 803. Char a, germination of, s. 222. Characees, reproductive organs and mode of reproduction of, s. 222. Character, individual ; share which the emotions take in the formation and development of, iii. 722 P. Charruan Indian, portrait of, iv. 1358. Cheeks (buccae), iii. 950. muscles, vessels, and nerves, iii. 950. use of the cheeks, iii. 950. Cheese, chemical properties of, ii. 18 ; iii. 359 ; s. 392. considered as an article of food, s. 39'2. Cheirogalevs, a genus of Quadrumana, iv. 215, et seq. See QUADRUMANA. characters of the genus, iv. 215. Cheiromys psilodactylus (aye-aye of Madagascar), iv. 221. anatomy of the, iv. 374, et scq. CHEIROPTERA (an order of Mammiferous Vertebrate Ani- mals), i. 594. characters by which the order is distinguished, i. 595. definition, i. 594. digestive organs, i. 599 ; s. 302. generation, organs of, i, 600. female, i. tiOO. male, i. 600. organs and mode of locomotion on land, iii. 455. wings and powers of flight of the, iii. 4-'30. organs of the senses, i. 598. of hearing, i. 5!)8. of sight, i. 598. of smell, i. 599. of touch, i. 599. of voice of the, iv. 1488. osteology, i. 595. pelvis of, s. 164. thymus gland amongst the, iv. 1095. Chelonia, an order of Reptilia, iv. 265, el seq. ciliary motion in, i. 631. digestive organs of, s. 301. pancreas of Chelonia, s. 95. organs and mode of progression of the, iii. 450. pelvis of, s. 170. thyroid gland in, iv. 1108. tongue of, iv. 1147. vocal organs of the, iv. 1502. Chclyosoma, a genus of Tunicata, iv. 1188, et seq. characters of the genus, v. 1188. Ch-mical rays of light, iv. 1437. Chemistry, organic and inorganic, similarity of the com- pounds supplied by each, i. 118. 124 ; iii. 1~52. Chemosis of cellular tissue between the conjunctiva and sclerotica, iii. 85. Chesnut, properties of the, as food, ii. 13. Chiasma of the optic nerves, iii. 762. 768. definition, iii. 768. chiasma in Invertebrata, iii. 769. in Osseous Fish, iii. 769. in Cartilaginous Fish, iii. 769. in Birds, iii. 769. in Amphibia and Reptiles, iii. 769. in Mammalia and Man, iii. 769. use of the chiasma, iii. 771. Chicken- breast, iv. 1039. Chills, influence of, on the state of general health, ii. 660. Chilodon ornatus, iv. 14, 15. Chilognatha, an order of Myriapoda, iii. 545. characters of the order, iii. 545. Chilopoda, an order of Myriapoda, iii. 546, et scq. characters of the order, iii. 546. Chimney-sweeper'1 s cancer, or cancer scroti,iv. 1014. Chimpanzee (Simia troglodytes), anatomy of the, iv. 198, ct seq. conformation of the, compared with that of man, iv. 1297. dentition of the, iv. 917. organs and mode of progression of the, iii. 455. organs of voice of the, iv. 1487. Chinchilla, anatomy of the, iv. 373, et seq. Chinese, cranium of, iv. 1325. women's feet, ii. 346. language, method by which the relation between the different words of the, that constitute sentences is in- dicated, iv. 1346. Chink of the glottis, or rima glottidis, which see. Chinook Indians, remarkable custom of the, iv. 1360. Chitine, or entomoline, ii. 881. chemical composition of, ii. 882. Chiton marmoratus, nervous system of the, iii. 606. Chlamyphorus truncatus, description of the, ii. 53. 55. Chloride of gelatin, ii. 405. Chlorine, action of, on protein, iv. 163. 164. Chloroform, effect of the inhalation of, iv. 6:<7. 1182. Chloromys Patagonica, or cavy of Patagonia, anatomy of the, iv. 384, et seq. Chloroproteic acid, iv. 163, 164. Chlorosis, state of the blood in, i. 428. Chccropotamidce, anatomy of the, iii. 859. Sec PACHYDER- MATA. Chceropus, a genus of Marsupialia, iii. 261, et seq. Choleliihs, or gall-stones, iv. 85. See Biliary Calculi; PRO- DUCTS, ADVENTITIOUS. Cholera, characters of the urine in, iv. 1292. state of the blood in, i. 428. syncope induced by, i. 797. Cholesteatoma, iv. 98. in tumours, iv. 98. granules, iv. 98. patches, iv. 98. scales, iv. 98. Cholesterine, or cholestearine, in gall-stones, i. 376. components of, i. 376. in the composition of the blood, i. 410; iv. 460. GENERAL INDEX. 763 CholfsU-finc — continued. in the brain, iii. 587, 588. found in various morbid growths, iv. 98. method of determining the presence of, in organic sub- stances, iii. 7%. 805. quantitative analysis of, iii. 793. Ckomdro-t>lotnu muscle, iv. 1133. Chundro- or costo-xiphoid ligament, iv. 1033. Cktmdro-ttenud articulation, iv. 1032. Chomiropterygii, a division of Fishes, iii. 956, et teq. characters of the division, iii. 956. Chorua tympani nerve, ii. 296. 549. 554 ; iv. 546. motor function of the chorda tympaai, iv. 553. canal of, ii. 556. Chorda: tending, ii. 581. 583. 601. Chorda: vocales, iii. 102. Iu5. interior and superior, iii. 10ft. destruction of the, by ulceration, iii. 119. morbid appearances, iii. 119. CAiintte Willisii, iii. 631. Chordee, causes of, iii. 721 L. ; iv. 1258- Chorea, affection of the medulla oblongata in, iii. 722 L. causes of, iii. 722 Q. principal central disturbance in, iii. 722 Q. Churion, or external covering of ovum, ii. 453; s. 3. 716. See GENERATION ; OVUM ; UTERUS AND ITS APPEN- DAGES. production of, in insects, s. [113. J development of the, s. [84.] Chorion of palpebrai conjunctiva, iii. 85. Choroid arteries, i. 492 ; iii. 704. coat or membrane, ii. 178, 179. corpus ciliare, ciliary processes, ii. 180. orbiculus s. circuius'ciliaris, — ciliary circle, ii. 180. pigmentum nigrum, ii. 180. structure of the choroid, ii. 178, 179. tapetum, ii. 179. plexuses of brain, iii. 675. plexus of nerves, iv. 525. plexus of the fourth ventricle, iii. 691. 693. plexuses of the lateral cerebral ventricles, iii. 634. crystalline formations in the choroid plexuses, iii. 63o. deposit of lymph in the, iii. 720 F. earthy concretions in the, iii. 720 F. vesicles in, formerly regarded as hydatids, iii. 720 F. Choroid gland, or muscle, in fishes, ii. 205. Chuitsinga, cranium of the, s. 5iS*. Chromatic aberration of light, iv. 143S. 1441. Chromato-dyopsis. See Achromatopsy ; VISION. Chromato-metablepsis. See Achromatopsy i VISION. Chromato-pseitdopsis. See Achromatopsy ; VISION. ( hromato-pscudopsy. See Achromatopsy ; VISION. Chrysalis form of insects, ii. 879. Chrysididce, or golden wasps, ii. 866. habits of the, ii. 866. Chyle, i. 29- GOO, 601 ; iii. 222. formation of, s. 355. 398. analysis of chyle, i. 29 ; ii. 19, 20 ; iii. 222. chemical and physical properties of, ii. 19 ; iii. 745. process of chylitication, ii. 19. taken from the thoracic duct, iii. 252. before reaching the thoracic duct, iii. 223. aniinalisation of, i. 29. sanguification of, i. 35. chyle globules, iii. 221, 222. chyle granules, iii. 221. motion of, iii. 221,222. causes of, iii. 222. microscopic characters of chyle, iii. 221. receptaculum chyli, iii. 206. 224. See also DIGESTION ; STOMACH AND INTESTINE. CHYLIFEROUS SYSTEM in (human anatomy), i. 602. See LYMPHATIC AND LACTEAL SYSTEM. CHYLIFCROCS SYSTEM (in comparative anatomy), i. 600. in .Amphibia, i. 601. See AMPHIBIA. in Aves, i. 601. See Avts. in Mammalia, i. 601. See MAMMALIA. in Pisces, i. 601. See PISCES. in Reptilia, i. 601. See REPTILIA. Chbliferous vessels, i. 601. See CHYLIFEROUS SYSTEM. Chyme, i. 601 ; s. 335. description of, i. 29; s. 398. analysis of, i. 29. properties of, ii. 16. process of chymification, ii. 16. See DIGESTION. Cicada hamatodes, or tree-hopper, ii. 86S. vocal organs of the, iv. 1503. Cicadidie, or tree-hoppers, i Cicatricula, or embryo-spot of ovum, ii. 452; s 68. 70. 73. See GENERATION ; OVUM. CICATRIX, i. 602. characters which mark cicatrices, i. 604, 605. nature of the new skin in cicatrix, i. 602, 603. process of restoration, i. 602. temperature of cicatrices, i. 605. of the intestine, s. 416. structure of the cicatrix, s. 416. Cicindela cainpestris, i. 111. Cicindeli'iep, ii. H60. Cigalee, vocal organs of the, iv. 1503. CILIA, i. 606. 1. in Infusoria, i. 606. uses, i. 607. 2. in Polypi and Sponges, i. 609. a. fresh-water polypi, i. 609. b. marine polypi, i. 610. c. sponges, i. 612. 3. ciliary motion of the ova of Polypi and Sponges, i. 613. uses, i. 613. 4. in Acalephae, i- 613. 5. in Actinia?, i. 614. 6. in Echinodermata, i. 614. uses, i. 616, 617. 7. in Annelida,! 617. 8. in Mollusca, i. 619 A. Gasteropodous Mollusca, i. 619. a. Nudibranchiata, i. 619. b. Cyclobranchiata, i. 620. c. Pectinibranchiata, i. 620. it. Pulmonifera, i. 621. B. Conchiferous Acephala, i.621. C. Tunicata, i. 623. 9. of the ciliary motion of the embryo of Mollusca, i. 626. Gasteropoda, i. 626. Acephala, i. 627. 10. phenomena of the ciliary motion in the Vertebrata, i. 628. A. Reptiles, i. 628. B. Birds, i. 631. C. Mammalia, i. 631. Ciliary motion : 1. summary of the animals in which the ciliary motion has been discovered, i. 632. 2. organs or parts of the body in which the ciliary motion has been ascertained to exist, i. 632. a. surface of the body, i, C32. b. respiratory system, i. 632. c. alimentary system, i. 632. d. reproductive organs, i. 633. 3. of the ciliary motion in the embryo, i. 633. 4. figure, structure, and arrangement of the cilia in general, i. 633. 5 of the appearance of the cilia in motion, i. 634. 6. duration of the ciliary motion after death and in separate pans, i. 634. 7. effects of external agents on the ciliary motion, i. 634. 8. effects of inflammation, i. 635. 9. of the power by which the cilia are moved, i. 635. 10. theory that the cilia have no real existence,!. 636. 11. of the motion caused in fluids by the cilia, i. 636. summary, i. 636. Cilia. See Eyelashes; Eyelids. Cilia of animalcules, iv. 6. Ciliary arteries, i. 491 ; iii. 786. anterior, i. 492; iii. 786. long, i. 491 ; iii. 786. short, i. 491 ; iii. 786. Ciliary circle of choroid, ii. 180. Ciliary or lenticular ganglion, ii. 2-1 ; iii. 785 ; iv. 622. Ciliary motion, i. 606. See CILIA. ol the tubuli uriniferi, iv. 253. nerve, ii. 282. branches, ii. 282. fasciculi, ii. 282. branch of nasal nerve, iii. 785. processes of choroid, ii. 180. processes of the vitreous humour, ii. 193, 194. Ciliobrachiata, digestive organs of the, s. 297. mode of reproduction of the, s. 22. CWo£rada(Acalephae), i- 36. Ciliograde animals, mode of progression of, iii. 432. Cinerea gelatinosa, substantia, iii. 653. C'mjH/MMzabdominis musculoso-aponeuroticum of Albinus and Haller, i. 2. Circassians, changes in the anatomical conformation ot the, iv. 1328, 1329. portrait of a young Circassian, iv. 1329. Circle of Willis, iii. 673. 705. Circular, or coronary, sinus, iii. 633. Circulation, apparatus of, in animals generally, i. 140. 143. See Arteries ; Veins. CIRCULATION (in physiology),!. 638. I. course of the blood in Man, i. 638. proofs of the circulation, i. 640. course of the blood in the foetus, i. 640. II. course of the blood in various animals, i. 641. in warm-blooded animals, i. 642. in cold-blooded Vertebrated Animals, i. 642. Reptiles, i. 96. 643. portal circulation in, i. 646. Fishes, i. 646. portal circulation of, i. 647. in Invertebrated Animals, i. 648. Acalephae, i. 654. Annelida, i. 650. arenicola, or sandworm, i. 650. erpobdella, or leech, i. 651. lumbricus, or earthworm, i.650. naides, i. 650. 3D 2 (61- GENERAL INDEX. CIRCULATION, Invertebratwl Animals, Annelida— continued. Arachnida, i. 652. Articulata, i. 650. Crustacea, i. 652. Entozoa, i. C54. Infusoria, i. 654. Insecta, i. 651. Mollusca, i. 648. Polypi, i. 654. See also CILIA. Zoophytes, i. 653. Echinodermata, i. 653. Planaria, i. 653. III. phenomena of the circulation and powers moving the blood, i. 655. 1. flow of the blood through the heart, i. 655. 2. phenomena of the arterial circulation, i. 658. a. velocity of the blood in different arteries, i. 659. b. force of the blood in the arteries and f>rce of the heart, i. 661. c. arterial pulse, i. 663. d. vital properties of the arteries, i. 664. e. influence of the vital powers of the arteries on the circulation, i. 667. 3. phenomena of capillary circulation, i. 660. a. structure and distribution of the capillary vessels, i. 669. b. properties of the capillary vessels, i. 6o9. 4. phenomena of the venous circulation, i. 674. IV. relation of the circulation to otherfunctions, i. 675. 1. to respiration, i. 675. 2. circulation within the cranium, i. 678. 3. influence of varieties in the distribution of arteries and veins upon the circulation, i. 678. 4. influence of the nervous system upon the circulation, i. 679. history of the discovery of the circulation, i. 681. Circulation in the brain, iii. 704. arterial, iii. 704. venous, iii. 705. question as to whether the amount of blood within the cranium is liable to variation, iii. 706. increase of circulation in running and leaping, iii. 479. decline of the, a sign of approaching death, i. 801. disorders of the venous circulation of the live-, i. 183. condition of the, during the sleep of hibernating ani- mals, ii. 771. animal and vegetable circulation compared, i. 133. circulation in comparative anatomy. See under the various headings. Circulus articuli vasculosus, i. 254. tonsillaris, ii. 497. Circumcision of females in Arabia, ii. 686. Circumduction, a motion of joints, i. 256. Circumflex artery, external femoral, ii. 246. 779. a. asceniling branch, ii. 246. b. descending branch, ii. 246. c. circumflex branch, ii. 247. internal, ii. 247. of scapula, iv. 436. posterior, iv. 436. iliac, ii. 842. origin and distribution, ii. 842. nerve (axillary) i. 361 ; iv. 436. 606. 759. cutaneous nerve of the shoulder, iv. 760. deltoid branches, iv. 760. veins, iv. 1407. iliac vein, internal, iv. 1412. superficial, iv. 1411. Circuwflexus palati muscle, iii. 951. relations and action, iii. 951. scapulae artery, i. 364. Circumvallate papilla? of tongue, iv. 860. 1 122. CIRRHOPODA (a class of Invertebrate Animals), i. 110. 683. characters of the class, i. 683. circulation, organs of, i. 689. definition, i. 683. division of the class, i. 684. external coverings and organs of support, i. 684. locomotion, organs of, i. 687. mortality and sensation, i. 688 ; iii. 607. reproduction, i. 690; ii. 411. development of the egg and young, i. 692. respiration, organs of, i. 689, secretion, organs of, i. 690. salivary glands of, iv. 432. Cirrhosis of the liver, iii. 188. See LIVER. serous effusion in, iv. 530. Cirri of Annelida, i. 167. Cirrigrada (Acalephse), i. 36. organs of digestion in, i. 41. food of, i. 43. locomotive powers of the, iii. 433. Cirripeda, characters of the class, i. 24»5. alimentary canal of the, s. 298. mode of reproduction of, s. [115.] CIRRONOSIS, i. 694 ; iii. 337. characters of the disease, i. 694. Clairvoyance, iv. 697. Classical languages, method by which the relation between the different words that constitute sentences is indicated in the, iv. 1346. Clavellina, a genus of Tunicata, iv. 1188, ct set/. characters of the genus, iv. 1188. Clavellinidce, a family of Tunicata, iv. 1188, ct scq . characters of the family, iv. 1183. genera of, iv. 1188. Clavicle, or collar-bone, ii. 154. development, ii. 156. structure, ii. 156. Clavicular extremity of sternum, iv. 1023. fascia, i. 360. ' nerves, iv. 753. Claws, structure of, s. 477. CWcA-beetle (Elater noctilucus), ii. 861. Climate, influence of, in the production of animal heat, ii. 670. effect of, on animal luminousness, iii. 199. constancy of the relation between climate and the complexion of the human race, iv. 1335. Climbing birds (Scansores), characters of, i. 268. Climbing, powers of, in serpents, iii. 448. Clinoid, or posterior ephippial processes, i. 726. process, anterior, or anterior ephippial, i. 728. Clio, a genus of Pteropoda, iv. 171. integument of, iv. 171. muscular system, iv. 172. locomotive apparatus, iy. 173. respiration and circulation iv. 173. nervous system, iv. 173. eyes, iv. 174. head-cowls and tentacula, iv. 174. conical appendages to the head, iv. 17"'. mouth, iv. 176. dental apparatus, iv. 176. generative system, iv. 177. Cftoborealis, i. 113. Clitoris, s. 709. blood-vessels of, s. 709. 713. cruia, glans, and prepuce of, s. 128. 709. ligaments and muscles of, s. 709. nerves of, s. 709. development, s. 710. high degree of sensibility of the, ii. 447. functions of, analogous to those of the penis ii. 446 447. abnormal anatomy of the, s. 714. abnormal development or excessive size of the, in cases of spurious hermaphrodism. ii. 6sO, 6*7. amputation of the, in Arabia and Egypt, ii.686. Closterinidce, a family of Polygastric animals, iv. 4, et seq. Closterium, mode of reproduction of, s. 219. Clot of blood, analysis of, i. 415. its importance in a curative point of view, i. 419. Clolhes-moths (Tineidse), ii. 867. Club-foot, anatomical characters of varieties of, ii. 348 causes of, iii. 132. plan of opera' ion for cure of, iii. 132. treatment for union of the tendon, iii. 132. Clubiona claustraria, development of spermatozoa in, iv. 490, 491. Clupcu harengus, or herring, eyes of, iii. 1002. tongue of the, iv. 1146. Clupeidce, a family of fishes, iii. 957. Coagulation of blood, phenomena of, i. 413. analysis of the crassamentum, i. 413. buffy coat, causes of. i. 414. importance of the clot in a curative point of view i. 419. Coats, or tunics, of Fallopian tube, s. 603. structure of, s. 603. of small intestine, muscular, s. 343. peritoneal, s. 341. of stomach, serous, s. 309. muscular, s. 310. of uterus, s. 629. Cobra di Capello. its mode of att'.ck, iii. 448. Cowper's gland, ii. 422. in man and in other animals, ii. 422. Coccidce, ii. 8(i8. Coccine, or animal matter of cochineal, ii. 881. Coccinella, or lady. cow, ii. 863. Coccygean branch of ischiatic artery, ii. 834. vertebrae of Carnivora, i. 474. See CARMVORA. Coccygeo-anal muscle, i. 17\ II. effects of, on animal heat, ii. 660. 675. See HEAT, ANIMAL. productive of sleep and hibernation, ii. 768. 775. severe, productive of torpor, ii. 768. syncope by, i. 797. Cold affusion, beneficial effects of, in cases of extreme excitement, ii. 681. £V>W-blooded animals, temperature of, as compared with warm-blooded animals. See HRAT, ANIMAL. Colds in the nose, in. 73*. See XOSE. Culeoptera, an order of Insecta, ii. 859. characters of the order, ii. 859. tribes and sub-tribes of, ii. 859, 860. various species of, ii. 8?>9— 863. nervous system of the, iii. 610. wings and powers of flight o'~, iii. 421. ColepinidtB (box animalcules), a family of Polygastric animals, iv. 4. characters of the family, iv. 4. Caleps, a genus of Polygastria, iv. 13. Coleridge, anecdote of, iv. 687- Colic artery, right, i. 195 ; s. 379. middle, i. 195 ; s. 379. left, s. 380. Colics' fracture, iv. 1517. Colliculus bulbi medius urethras, iv. 1248. seminalis, iv. 1252. See Caput gallinaginis. Colliers, peculiar disease of the lungs to which they are liable, iv. 117. Colliquainentum of the ova of Arachnidans, i. 213. Colloid, i. 694. Colloid cancer, characters of, iv. 137. of the testicle, iv. 1010. Culloma, iv. 135. ('..•lloredo, Lazarus, the heteradelph, iv. 969. Collum. See NECK. Colobux, a genus of Quadrumana, iv. 196, et seq. See QUADRUMANA. characters of Colobus, iv. 196. Colon, or great gut, anatomy of the, s. 365. ascending, iii. 941 ; s. 365. transverse, iii, 944 ; s. 365. descending, iii. 944 ; s. 365. sigmoid flexure, iii. 944 ; s. 3G5. appendices epiploicae, s. 366. movements of the large intestine, s. 366. mucous membrane of the colon, s. 363. development of the colon, s. 402. uses of, in digestion, ii. Id. Colostrum, or first milk after parturition, iii. 360. chemical properties of, iii. 360, 361 ; s. 391, note. Colouring matter of the blood, i. 41 1. See BLOOD. Colours, relative effect of different-coloured uniforms on the chances of being hit in battle, iv. 1441, note. Colfiudeadec (breast animalcules), a family of Polygastric animals, iv. 5. characters of the family, iv. 5. Coluber natrix (ringed snake), nervous system of the, iii. 620. scaber, Linn., iv. 886. verus (viper), nervous system of the, iii. 621. Columba (pigeon), nervous system of the, iii. 622. Columelii cochleae, ii. 531. Columnn nasi, iii. 726. Columns carneae, teretes lacerti, ii. 581. foraminis ovalis, ii. 580. rugarum of vagina, s. 706. Columns of medulla oblongata, anterior pyramidal, iii. G7i>. Columns of nrudulla oblongata — continued. olivary, iii. 679. 683, 684. posterior pyramidal, iii. 679. 6S3, 684. restiform, iii. 678, 679— 'J82. 684. of the rectum, iii. 921. of the spinal cord, functions of the, iii. 721 NT. office of the antero-lateral columns, iii. 721 O. of the posterior columns, iii. 7'21 p. manner in which the posterior columns may contribute to the exercise of the locomotive functions, iii. 721 Q. Colurus, a genus of Rotifera, iv. 406. Coma, phenomena of, iii. 722 Y. 723 B. comparison between sleep and, iv. 677. death by, mode of, i. 264. Comalula, alimentary canal of, s. 297. muscles of the, iii. 537. Combustibles used in organic analysis, iii. 814. Combustion, hypothesis of, as the physical cause of animal heat, ii. 684. Combustion apparatus of Liebig for organic analysis, iii. 814. Commtssural nervous fibres, iii. 646. Commissure of the optic nerves, iii. 673. 676 ; iv. 1446. antero-posterior of lornix, iii. 675. See Fornix. Commissures of cerebellar hemispheres, iii. 685. of the brain, iii. 701. longitudinal commissures, iii. 701. superior longitudinal, iii. 701. longitudinal tracts, iii. 701. fornix, iii. 701. taenia semicircularis, iii. 702. transverse, iii. 702. corpus callosum, iii. 702. anterior commissure, iii. 702. posterior commissure, iii. 703. soft commissure, iii. 703. manner in which the commissures connect the parts between which they are placed, iii. 703. functions of the commissures, iii. 723 D. corpus callosum, iii. 723 D. fornix, iii. 723 D. pons Varolii, iii. 723 E. Commissure, anterior, s. 709. posterior, s. 709. cerebro-cerebellar commissures, or processus cere- bell i ad testes, iii 693. long and hidden, iii. 691. of the spinal cord, white, iii. 652. grey, iii. 652. short and exposed, iii. 691. single, iii. 691. superior longitudinal, iii. 697. of third ventricle, anterior, iii. 676. posterior, iii. 676. soft, or grey, iii. 677. Communicant noni, or internal descending cervical nerve, iv. 753. tibialis nerve, iv. 62. ulnae artery, iv. 226. Communicating artery, anterior, iii. 704. posterior, iii. 704 branches of acromial nerves, iv. 753. Comparison between the development of the cerebrum and cerebellum in the adult, iii. 687. between the structure of the sympathetic and the cerebro-spinal fibre, according to Volkmann and Bidder, iii. 599. of nervous and muscular tissue, iii. 593. Complexion, differences in the, of the various races of mankind, iv. 1333. constancy of the relation between climate and com- plexion, iv. 1335. historical evidence of an actual change of complexion in tribes or races that are known to have migrated from one locality to another of a different character, or to have changed their mode of life, iv. 1336. Complexus muscle, i. 371. 732. Compressor narium minor, iii. 729. Compressor venae dorsalis penis muscle, ii. 446; iii. 916. Compressores urethrae muscles, iii. 932 ; iv. 1247 ; s. 138. Cumpressorium, the, iii. 347. See MICROSCOPE. Conception, physical action in, iii. 72 I. ch niges in the uterus after, ii. 454. circumstances influencing the liability to concep- tion, ii. 456. lactation usually a preventive to conception, ii. 457. signs of recent conception in women, ii. 457. See GENERATION ; OVUM ; UTERUS, AND ITS APPEN- DAGES. Concha of ear, ii. 551. CONCBIFERA (a class of Invertebrate Animals), i. 112. 694. characters of the class, i. 694, 695. classification of the Conchifera, i. 714. division of the class, i. 695. nervous system, i. 704 ; iii. 603. organs of digestion, i. 695. of circulation, i. 098. of respiration, i. 699. of generation, i. 700 ; ii. 410. 3D 3 7G6 GENERAL INDEX. CONCHIFERA — continued. organs of motion, i. 700. skin and its appendages, i. 705. 1. mantle, i. 705. 2. siphons, i. 707. 3. shell, i. 707. cardinal edge, i. 708. general structure, i. 707. hinge, i. 707. ligament, i. 7C8. valves, surfaces of the, i. 710. external surface, i. 710. 1. the hooks, i.710. 2. the belly of the shell, i. 7 1 1 . 3. the edges, 1.711. 4. thelunula, i. 711. 5. the corselet, i. 711. internal surface, i. 712. formation of mother-of-pearl and of pearls, i. 712, 713. Concretions, or pseudo-calculi, iv. 8G. See PRODUCTS, ADVENTITIOUS.- found in the paunch and reticulum of Ruminantia, s. 538. polypous, in the heart, ii. 648. of prostate gland, iv. 158. Concussion, depression of the heart's action consequent on, i. 723. Condillac's dreams, iv. 687. Condiments, employment of, in diet, ii. 15. Condyles of femur, iii. 44. humerus, external, i. 217. internal, i. 217. extensorius of humerus, ii. 1GO. of the tibia, ii. 168. Condyloid foramen, i. 732. posterior, i. 732. anterior, i. 732. processes, i.732; ii. 215. Condylopeda, i. 245. Conferva fontinalis, arrangement of the sexual reproduc- tive organs of the, s. 220. Confervoiil Alga?. See Algce ; REPRODUCTION, VEGETABLE. Conflux of Majendie, anterior, iii. 640. inferior, iii. 640. posterior, iii. 638. 640. 688. superior, iii. 640. Congenital deformities. See TEKATOLOGY. Conger, tongue of the, iv. 1146. Congestion of the liver, iii. 183. o. general congestion, iii. 184. b. hepatic venous congestion, iii. 184. e. portal venous congestion, iii. 184. of the venous sinuses of the spinal cord, iii. 713. convulsions, iii. 713. spinal apoplexy, iii. 713. Conglobate glands, i. 23. Congregation, instinct of, both in man and in the lower animals, iii. 16. imperfect societies of insects, iii. 16. for society alone, iii. 16. of males in the pairing season, iii. 16. for emigrating together, iii. 16. for feeding together, iii. 16. for some common work, advantageous to the community, iii. 16. occasional association, iii. 17. .of higher animals for various purposes,— grega- rious animals, iii. 17. Coni vasculosi of epididymis, iv. 979. Conical appendages to head of Pteropoda, iv. 175. Conium, use of, in cases of muscular disturbance, iii. 721. H. Conjoined tendons, the, i. 6. Conjunctiva (in human anatomy), ii. 173. 176 ; iii. 83. See LACHRYMAL ORGANS. structure of, ii. 176. Conjunctivitis, iii. 86. Conochilus, a genus of Rotifera, iv. 402. Conochilus volvox, a species of Rotifera, iv. 401, el seq. Conoid or pyramidal ligament, iii. 104. Consistence, in organised and unorganised bodies, i. 119. Constriction of the alimentary canal, s. 404. causes, s. 404, 405. of the aorta, i. 191. Constrictor ani muscle, i, 176. isthmi faucium muscle, iii. 952 ; iv. 1133. relations and action, iii. 952. pharyngis muscle, iv. 1102. pharyngis muscle, inferior, iii. 102, 940. medius, iii. 946. superior, iii. 946. vaginae muscle, i. 178 ; s. 712. Consumption, tubercular, aphonia a symptom in cases of, iii. 119. sympathetic ulceration of the trachea and bronchial tubes in cases of tubercular, iii. 119. CONTRACTILITY, i. 716. 1. irritability, i. 717. 2. vital power orproperty of irritability, i. 719. 3. conditions accessary to the contractile power, i. 721. CONTRACTILITY — continued, 4. laws regulating the vital powers of contractile powers, i. 723. conclusions, i. 724. Contractility of muscle, i. 710 ; iii. 519. is it a property inherent in muscular fibre ? — doc- trine of the " vis inaita " of Haller, iii. 519. source of contractility, whence derived, iii. 5*0. relation of contractility to the state of nutrition of the organ, iii. 520. Dr. John Reid's experiments, iii. 520. evidence furnished by cerebral paralysis, iii. 521. corroborations furnished by the fact .that throughout the animal kingdom the vascular supply is accurately proportioned to the mus- cular irritability, iii. 521. See MUSCULAR MOTION. of cavities of the heart, duration of, after death, ii. C07, 608. Contraction, or systole, of the auricles and ventricles of the heart, ii. 602, 603. See HEAKT, PHYSIOLOGY OF. Conus arteriosus of Woolf, ii. 581, note. Convoluted tube forming the lymphatic gland, iii. 218. See LYMPHATIC SYSTEM. Convolutions of the brain, iii. 693. functions of the cerebral convolutions, iii. 722 X. connexions of the functions of the mind with the functions of the cerebral convolutions, iii. 722 X. Dr. Wigan's doctrine of the duality of the mind, iii. 722 Z. sensation, iii. 723 A. volition and attention, iii. 723 A. sleep, iii. 723 B. dreaming, iii. 723 B. coma, iii. 723 B. somnambulism, iii. 723 B. delirium, iii. 723 B. fibres of the centrum ovale, iii. 723 B. Convulsions, congestion of the vessels of the brain conse- quent on, iii. 713. 720 F. cause of the convulsions of epilepsy, iii. 721 G. of the foetus in utero, ii. 321. Cooking, importance of, indigestion, ii. 12. chemical changes induced iu food by the process of cooking, s. 390. roasting meat, s. 390. boiling meat, s. 390. salting and smokine: meat, s. 391. Cophias, poison fangs of, iy. 291. Copper, method of determining the presence of, in organic substances, iii. 805. Copts, physical characters of the, iv. 1357. Cor bovinum, ii. 639. Coraco-acromial ligament, i. 359. Coraco-brachialis muscle, i. 217. 219. 359; ii. 160; iv. 756. Coracoid notch (incisura semilunaris, lunula), ii. 1M>. process, i. 359 : ii. 157 ; iv. GOO. fractures of the, iv. 600. in Carnivora, i. 46G. See CARNIVORA. Coral, red, of commerce, (Corallium rubrum) iv. 31, 32. Coral reefs, formation of, iv. 33. mode in which coral reefs become converted into islands and fitted for the abode of man, iv. 33. CorallidcE, or cortical polyps, a family of Polypifera, iv. 19. 30. characters of the family, iv. 19. genera, iv. 19. Corallium rubrum, iv. 31. Isis hippuris, iv. 31. ova of, s. [127.] Cordiform tendon, ii. 2 ; iv. 324. Corn, considered as an elementary substance, s. ?,93. constituents, s. 393. bread, s. 393. Corw-fields, ravages of the wire-worm in thp, ii. 861. Cornea, ii. 175—177. chemical composition, ii. 177. development, ii. 178. size and shape, ii. 176; iv. 1440. structure, ii. 175. wounds and diseases of the cornea, ii. 177. conjunctiva! covering of the, iii. 87. opaca, ii. 175. 177. transparens, ii. 175, 170. conical, symptoms of, iv. 1404. Cornicula laryngis, or tubercles of Santorini, iii. 101 102. Corns, hard, causes of, ii. 353. solt, causes of, ii. 353. on roots of fingers, ii. 524. Cornu Ammonis, iii. 675. Cornua of hyoid bone, greater, iv. 1124. lesser, iv. 1124. of lateral ventricles, iii. 674. See Ventricle. of thyroid cartilage, iii. 102. Corona ciliaris of Camper and Zinn, ii. 193. of glans penis, iii. 914. Cornnte, i. 728. See Frontal bone. GENERAL INDEX. 7G7 Coronal suture, i. 736. L'oroiiaria ventriculi, or proprr gastric, artery, i. 194; iii. 911 ; s. 325. ventriculi vein, iv. 1414. Coronary arteries, i. 189. 192. 194 ; ii. 584. labial, interior, i. 486. superior, i. 487. ligament, i. 251 ; iii. 161. of the liver, iii. 940. plexus of nerves, superior, s. 429. sinus, iii 6:i3. vein, iv. 1404. great or anterior, ii. 596 ; iv. 1414. sinus of, ii. 597. posterior or lesser, ii. 597 ; iv. 1415. smaller anterior, ii. 597. Coronoid process, ii. 66. 215. process of ulna, ii. i62. structure of the, ii. 163. Corpora albicantia, or mammillaria, iii. 673. 676. 701. cavernosa, s. 709. geniculata, their relation to the optic nerves, iii. 768. Malpighii, iv. 243—249. epithelium of, iv. 252. function of the, iv. 254. mammillaria, or albicantia, iii. 673. 676. 701. fibrous matter and connections, iii. 701. structure, iii. 701. olivaria, olivas, iii. 679. 683, 684. corpus dentatum, iii. 683, 684. functions of the, iii. 722 O. Pacchioni, iii. 629, 632. 644. 691- quadrigemina, iii. 677. 685. functions of the, iii. 722 M. restiformia, iii. 678, 679. 682. function of the, iii. 722 K. striata, iii. 698- colour, iii. 699. course of fibres, iii 699. sections, iii. 699. vesicular matter, iii. 699. functions of the, iii. 722 L. the centre of volition, iii. 722 L. 723 E. Wollfiana, iv. 982. Corpus bulbosum penis veins, iii. 917. cavernosum penis artery, iii. 916. Arantii, i. 223 ; ii. 581. callosum, the, iii. 625. 674. longitudinal tracts of, iii. 674. 702. connexions, iii. 702. fibres of corpus callosum, iii. 702. development, iii. 702. anterior reflected portion, iii. 675. office of the corpus callosum, iii. 723 D. cavernosum clitoridis, erectile tissue of, ii. 446. cavernosum penis, iii. 912. structure, iii. 912. crura penis, iii. 912. ligamentum suspensorium penis, iii. 912. trabecuke, iii. 912. septum pectiniforme, iii. 913. vaso-rellular structure of penis, iii. 913. contractile fibrous tissue, iii. 913. erectile tissue, ii. 145. structure, ii. 145. of Santorini. s. 712. of penis in Mammalia, ii. 423. ciliare, ciliary processes of choroid, ii. 180. conicum. See Parovartum. dentatum, or rhomboideum, cerebelli, iii. 683, 684. 6B2. fimbriatum, iii. 675, 676. geniculatum, externum, iii. 700. internum, iii. 700. fornicis, iii. 676. glandulosum, iv. 146. See PROSTATE GLAND. urethra, iv. 1264, 1265. Highmori, iv. 1'77. luteum, nature of a, s. 564. 569. origin and formation of the, ii. 449. lobular structure of the, ii. 419. size, when fully developed, ii. 449. variations in length of time required for full deve- lopment, ii. 450. hypothesis that the corpora lutea are matrices in which the Graafian vesicles and ova are formed, refuted, ii. 450. uses of the corpora lutea, ii. 451. See also Ovary. sesampideum, i. 223 ; ii. 581. spongiosum, iv. 1218. 1251. artery of the corpus spongiosum, iv. 1254. urethra?, iii. 914. erectile tissue in the, ii. 145. structure of the, ii. 145. in Mammalia, ii. 423. strictum, iii. 675. Corpuscles of the blood, i. 404. See BLOOD. appearance of, in the chyle, iii. 222. ganglionic, structure of, s. 436. Malpighian,iv.775-779. functions of the, iv. 799. Corpuscles — continued. of Morgagni, ii. 581. or cells of bones, iii. 850. See OSSEOCS TISSUE. Pacinian. See PACINIAN BODIES. of pus, iv. 111. seminis. See Spermatozoa. Corpusculum Weherianum. See VESICUH PROSTATICA Corrugator supercilii muscle, i. 748 ; ii. 222 ; iii. 80. See CRANIUM, Muscles of the. Cortical substance of the kidney, iv. 236. polyps. See Corallfdts. Coryne, ova of, s. [127.] Coryphodon, the. See PACHYDERMATA. Costte, or ribs. See RIBS. Costal cartilage, iv. 1024. 1031. muscles of Vertebrata, iii. 542. tulcus, iv. 1026. Co» to-abdominal muscle, i. 5. -coracoid ligament, i. 360. -humeral branches of the second and third inter- costal nerves, i. 360. -sternal articulations, iv. 1032. -transverse ligament, anterior or long, iv. 1032. posterior, iv. 1032. -vertebral articulations, iv. 1032. ligaments, iv. 1032. -transverse ligament, middle or interosseous, iv. 1032. -xiphoid ligamer.t, iv. 1033. Cotugno, liquid of, ii. 536. Cotunnius, nerve of, ii. 287. Cotyloid cavity, or acetabulum, s. 116. fossa, s. 1 16. ligament (ligamentum cotyloideum, fibro-cartila- gineum, labium cartilagineum acetabuli), ii. 777. notch, s. 116. Cotylo-sacral, or standing, arch of pelvis, s. 139. Coughing, iii. 735. probable causes of, iii. 722 K. Couia (Myopotamus), anatomy of the, iv. 373, el seq. Coursing birds (Cursores), characters ot, i. 268. Cow, pelvis of the, s. 158. skeleton of the, 508. urine of the, iv. 1280. milk of the, iii. 358 ; s. 391. See MILK. Cowper's glands, iii. 930 ; iv. 1247. 1252. development of, iv. 1256. properties of the fluid supposed to be derived from, ii. 458. uses of the glands, ii. 459. comparative anatomy, iv. 1253. COXCE, morbus, iv. 434. Coralgia, influence of, upon the pelvis, s. 208. Crabs, migration of the, iii. 14. object of the migration of the land-crab, or tourlourou of the French, iii. 14. Crab, land (Cancer cursus), velocity of the, iii. 444. lamina of shell of crab, iv. 570. muscles of the, iii. 540. hermit-crab, nervous system of the, iii. 613. luminousness of a species of, iii. 198. See CRUSTACEA. Crabronidee, a family of the order Hymenoptera, ii. 865. Cramp, or spasm, iii. 720 K. Cranial aponeurosis, i. 748. sinuses, iv. 1387. Crania-vertebral nerve, iii. 707. CRANIUM (in human anatomy), i. 725. analogy between a cranium and vertebra, i. 740. and several vertebrae, L 740. articulation of the cranial bones— sutures, i. 736. bones of the cranium, i. 726. 1. sphenoid bone, i. 726. articulations, i. 728. body of the bone, i. 726. cells, sphenoidal, i. 726. development, i. 728. surfaces, i. 726. 2. frontal bone, i. 728. articulations, i. 730. development, i. 730. external surface of the frontal portion, i. 729. orbital portion, i. 730. posterior or cerebral surface, i. 729. under surface, i. 729. upper surface, i. 729. 3. ethmoid bone, i. 730. articulations, i. 731. cells, i. 731. development, i. 731. 4. occipital bone, i. 731. angles, i. 731.732. connexion,!. 733. development, i. 731. 5. temporal bone, i. 733. connexions, i. 735. development, i. 735. mastoid portion, i. 734. petrous portion, i. 733. squamous portion, i. 734. 3D 4 768 GENERAL INDEX. CRANIUM, bones of — continued. 6. parietal bone, i. 735. angles, i. 736. borders, i. 736. connexions, i. 736. development, i. 735. surfaces, external and internal, i. 735. bones of the, media by which sound is communicated, ii. 568. circulation within the, i. 678. See CIRCULATION. blood-vessels within the, i. 678. motions observable at each arterial pulsation, i. 678. development of the cranial bones, i. 741. divisions of the cranial bones, i. 725. • base, i. 725. anterior, i. 739. middle, i. 739. posterior, i. 739. Calvaria, i. 725. occiput, i 725. sinciput, i. 725. temples, i. 725. vertex, or bregma, i. 725. measurements of the cranium, i 739. capacity and weight of the skull of the Negro, iii. 666. and of other races, iii. 066. anatomical differences of the cranium by which the several races of mankind are distin- guished from each other, iv. 1319. prognathous type, iv. 1321. pyramidal type, iv. 1322. oval or elliptic tvpe, iv. 1323. measurements of the capacity of the cranium of different races, iv. 1324. mechanical adaptation of the cranium, i. 742. surfaces of the cranium, i. 737. external surface, i. 737. inferior region, i 737. anterior division, i. 737. middle division, i. 738. posterior division, i. 738. lateral region, i. 738. superior region, i. 737. internal surface, i. 73H. correspondence of the external and internal sur- faces, i. 73.t. the cranium a distinctive characteristic of the su- periority of man, iv. 1295. cranium of man compared with that of the lower animals, iv. 1295. abnormal conditions of the cranium, i. 744. acephalia, i. 744. adhesion, i. 746. caries, i. 746. changes from age, i. 745. encephalocele, i. 744. evolution, insufficient, i. 744. exostosis, i. 7-15. inflammation, effects of, i. 745. medullary sarcoma, i. 746. necrosis, i. 746. ossa Wormiana, i. 744. sutures, obliteration of the, 5. 745 persistence of certain, i. 744. symmetry, want of, i. 744. thickening, extraordinary, i. 745. thinness of the parietes (hydrocephalus), i. 744. extraordinary thinness,!. 745. congenital deformity of, iv. 954. acrania, iv. 954. injuries of the cranial bones of the foetus in utero, ii. 321. cranial tumours of the foetus in utero, ii. 321. See TERATOLOGY. American custom of altering the form of the skull by artificial compression, iv. 1360. CRANIUM, REGIONS AND MUSCLES OF THE (surgical ana- tomy), i. 746. division into regions, i. 746. I. occipito-frontal regions, i. 747. arteries, i. 748. integument, i. 747. sympathies, i. 748. muscles, i. 747. corrugator supercilii, i. 748. occipito-frontalis, i. 747. nerves, i. 748. pericranium, i. 748, 749. subcutaneous tissue, i. 747. veins, i. 748. II. temporo-parietal region, i. 749. arteries, i. 749. lymphatics, i. 749. muscles, i. 749. nerves, i. 749. pericranium, i. 749. temporal fascia, i. 749. veins, i. 749. CRANIUM (comparative anatomy,) i. 724 ; iii. 825. bones of the cranium, iii. 828—833. CRAMUM (comp. anat.)— continued. definition, i. 724. description, i. 724, 725. in Aves, i. 725. in Marnmifera, i. 725. in Pisces, i. 725. in Reptilia, i. 725. Craspedosoma, a genus of Myriapoda, iii. 546, et seq, Craspedosomad.ee ^ a family of Myriapoda, iii. 516, et scq. Crassamentum of blood, analysis of, i. 415. Craw, or crop, of birds, functions of, ii. 11. Craw-fish, river (Astacus fluviatilis), ovum of, s. [115], note, Cremaster muscle, i. 6; iv. 982. 984. 980. actions of the muscle, iv. 986. Creophilus maxillosus, or rove-beetle, ii. 863. Crepuscular ia, sphinges or hawk-moths, a section of Insects of the order Lepidoptera, ii. 8G6. characters of the section, ii. 806. Crest of the ilium, s. 114. of the pubis, s. 115. sacral, s. 119. of tibia, or shin, iii. 45. Cretins, goitre of, hereditary, ii. 471. Cribriform process or plate, i. 730. Cribrose macula, ii. 530. Cribrum, i. 730. foramina of, i. 731. Cricket, house (Acheta domestica), ii. 864. powers of leaping of the, iii. 474. organs of voice of the, iv. 1503. mole-cricket (Gryllotalpa yulgaris), ii. 864. Cr/co-arytenoid articulation, iii. 105. -arytenoideus posticus muscle, iii. 101. 102. 109. lateralis, iii. 101, 102. 107. -thyroid articulation, iii. 104. ligaments, i. 251 ; iii. 104. lateral, iii. 105. artery, iii. 573. muscles, iii. 101. 105. action, iii. 106. -tracheotomy, operation of, iii. 574. Cricoid cartilage, iii. 101. Crispatura tendinum, or contraction of the fingers from disease of the palmar fascia, ii. 266. 517. 525. Crista galli of the ethmoid bone, i. 730 ; iii. 629. ilii, ii. 500. mentalis externa, ii. 213. interna, ii. 214. urethra?, iv. 1252. See Caput gallinaginis. Cristate process of the ethmoid bone, i. 729, 730. CristateUa mucedo, ovum of, s. 52. Crocodiles, anatomy of, iv. 266, et seq. musk gland of the crocodile, iv. 325. abdomen in, i. 1. organs and mode of progression of the, iii. 449. pelvis of the, s. 171. skeleton of a, iii. 822, et scq. teeth of, iv. 895. tongue of the, iv. 1146, 1147. vocal organs and voice of the, iv. 1502. Crocodilidce, a family of Heptilia, iv. 265, et seq. Crop, craw, or ingluvies of birds, uses of, ii. 11 ; s. 301. of insects, s. 298. Crotalus durissus (rattlesnake), anatomy of the, iv. 283, it scq. Croton sebiferum (tallow-tree), i. 58. Croup, or acute laryngitis of children, iii. 115. age at which it occurs, iii. 115. condition of the lungs and brain in fatal cases of, iii. 116. false or .idventitious membrane of croup, iii. 116. origin of, iii. lift. stages of, described, iii. 1)5. first stage, iii. 115. second stage, iii. 115. third or last stage, iii. 116. bronchial, s. 293. acute asthenic, of adults, or diphtherite, iii. 117. cerebral. See Croup, spasmodic, spasmodic croup described, iii. 124. hypotheses as to causes of, iii. 124. Croupy or diphtheritic inflammation of the alimentary canal, s. 411. Crown of the head, i. 747. Crucial ligaments, i. 251. of knee, anterior, iii. 46. posterior, iii. 46. Cruor of blood, analysis of, i. 415. Crura cerebelli, ii. 270. 272 ; iii. 674. 677. G85. f>92. peduncles of crus cerebelli, iii. 693. inferior, iii. 693. middle, iii. 6-J3. superior, — processus cerebelli ad testes, or cerebro-cerebellar commissures, iii. 693. or pedunculi cerebri, ii. 272; iii. 673. 678, 679. clitoridis, s. 138. 709. interna, s. 712. of the diaphragm, i. 1 1 ; ii. 3. penis, iii. 91 2; s. 138. artery of the, iii. 934. durceus muscle, nerve for the, iv. 763. GENERAL INDEX. 769 Cniral arch, i. 5, note, 13 ; ii. 7r>6, 757- canal, ii. 757. fascia, or fascia lata, s. 138. nerve (femoral), iv. 762. branches, iv. 763, 764. anterior, ii. 779; iv. 761. ring, ii. 757. passage of the testicle through the, iv. 988. vein, anterior, ii. 838. Crural or femoral hernia, ii. 756. See HERNIA. symptoms and progress of the disease, ii. 7-i9. Crttsia petrosa of teeth, iv. 864, 8G5. CRI-STACEA (a class of Articulated Animals), i. 111. 24G. 750. arrangement of the class, tahle of the, i. 751. blood and circulation, i. 652. 775. brancho- cardiac (efferent) vessel, i. 777. entrance of the blood into the heart, i. 777. heart and arteries, i. 776. venous sinuses, i. 777. definition, i. 750. digestion, organs of, i. 771. biliary system, i. 775 ; iv. 447. mouth and its appendages, 771. 773. intestinal canal, i. 773; s. 298. oesophagus, i. 773. stomach, i. 773. generation, organs of, i. 782 ; ii. 417. ova ol Crustacea, s. [115.] spermatozoa of Crustacea, iv. 493. ovum, i. 785. incubation and development, i. 785. metamorphoses, i. 786 muscular system of the, iii. 540. nutrition, apparatus of, i. 771. respiration, organs of, i. 777. sensation, apparatus of, i. 702. nervous system, i. 762 : iii. 608. senses, organs of the, i. 7»J7. hearing, i. 768. sight, i. 769. smell, i. 768. taste, i. 768. touch, i. 767. skin, or tegumentary skeleton, and organs of locomo- tion, i. 752 ; iv. 309. moult, or process of renovation of the tegumen- tary skeleton, 1. 759. reproduction of extremities, i. 7CO. temperature of, ii. 650. periodical exuviation of the shell of Crustacea, iv 571. list of Crustacea possessing the property of luminous- ness, iii. 197. See LUMINOUSNESS, ANIMAL. effects of atmospheric electricity on, iii. 36. Cryptogamia, mode of reproduction of the higher, s. 232. vegetative system among the lower Hepaticae, s. 232. first period — from the germination of the spore, s. 233. development of the antheridia, s. 233. development of the archegonia, s. 233. second period — fructification of the archegonia, s. 234. changes preparatory to the development of the spores, s. 234. development of the spores, s. 234. vegetative system in Jungermannise frondosae, s. 235. first period— germination of the spores, s. 235. the antheridia, s. 235. the archegonia, s. 235. second period— development of the embryo, s. 230. changes preparatory to the development of the spores, s. 236. Mosses, s. 2*7. first period— gemination of the spore, s. 238. development of the antheridia and archegonia, s. 238. in the Phascum, s. 238. development of the fruit, s. 238. of the spores, s. 239. Ferns, s. 239. first period— germination of the spore, s. 239. the antheridia, s. 239. the archegonia, s. 240. origin of each archegonium, s. 240. the embryo, s. 241. sporangia and spores, s. 241. F.quisetacex, s. 241. first period— germination of the spores, s. 211. antheridium, s. 241. archegonium, s. 212. spores and sporangia, s. 242. Lycopodiacese, s. 243. commencement of the development of the pro- thallium, s. 243. archegonia, s. 243. embryo, s. 243. sporangia and spores, s. 243. Rhizocarpeae, s. 215. macrospore of Pilularia, s. 245. prothaUium, 8. 245. , embryo, s. 245. sporangia and spores, s. 246. Cri/pfogamia — continued. review of the analogies which present themselves in the history of the development of the repro- ductive organs of the higher Cryptoganua and of the Phanerogamia, s. 252. 1. analogies existing between the ovule, the an- ther, and the sporangium, s. 252. 2. analogy between the embryo sac, the pollen- cell, and the parent cell of four spores, s. 252. origin an.! development of germ-cells in special organs destined for their reception, s. 253. Cryptomonadinidtz, a family of Polygastric Animals, iv. 3. characters of the family, iv. 3. Cryptops, a genus of Myriapoda, iii. 547, et seq. Crystalline lens, or crystalline humour, of the eye, ii. 191. aqua Morgagni, ii. 200. capsule of the lens, Ii. 199. chemical composition, ii. 197. development, ii. 195. form and shape, ii. 194, 195. size, ii. 195. Crystals of unorganised matter, symmetry of, iv. 852. Cubital process, ii. 160. Cuboid bone, ii. 340. structure and development, ii. 341. connexions and articulations, ii. 343. abnormal conditions, ii. 347- Cuckoo, its mode of climbing and apparatus for prehension, iii. 451. Cud, chewing the, or rumination, ii. 11. causes of, ii. 11. Cuendu (Hystrix prehensilis), anatomy of the, iv. 377 , et seq. Culicidee, or gnats, ii. 867. Culus. See ANUS. Cumulus of egg, s.551. 73. [90.] formation of the cumulus, s. [90.] Cuneiform bone of carpus, ii. 505 ; iv. 1506. articulations, ii. 505. 5(9. of tarsus, external, ii. 341. internal, ii. 340. middle, ii. 341. structure and development, ii. 341. abnormal conditions, ii. 347. cartilages, iii. 101. 103. Cuneo-scapheid articulation, ii. 343. Cupola of cochlea, ii. 531. Curculionidcc, ii. 864. Curd and whey, mode of converting milk into, s. 538. Cursores, or coursing birds, characters of, i. 268. Curvature ot the spine, iv. 1036. of the stomach, lesser, s. 308. greater, s. 308. Cutaneous affections of the foetus in utero, ii. 333. follicles, ii. 482. nerve, external, i. 217. 361 ; ii. 64 ; iv. 756. branches to coraco-brachialis, iv. 756. to biceps, iv. 756. for brachialis anticns, iv.756. internal, i. 217. 361 ; ii. 64 ; iv. 755. 763. middle, iv. 763. of arm, internal, ii. 361. inferior perforating, iv. 763. superior perforating, iv. 763. long, ii. 352. palmar, iv. 757. perona?al, iv. 768. of the shoulder, iv. 760. of Wrisberg, iv. 756. or anterior, surface of nasal bone, ii. 212. respiration of Amphibia, i. 103. secretion of Amphibia, i. 103. tibial, or reflected, branch of saphaenus nerve, iv. 764. Cuticle, the, iii. 489. Cults, framework of, in what it consists, iii. 495,496. of tongue, iv. 1135. Cutleria, mode of reproduction of the, s. 214. Cuttle-fish, curious mode of discharging the seminal fluid in the, ii. 458. sepium, or cuttle-bone, i. 531. 546. ink-bag of, iv. 453. ova of, s. [TOS], [106.] Cuttle-fishes, or Sepiadae, i. 521. Cyanea aurita, ova of, s. [129.] Cyanogen, discovery of, iii. 151. combinations of, with metals, iii. 151. effect of, on the action of the heart, i. 797. Cyanosis, i. 190. Cyclica, a sub-tribe of Insects of the order Coleoptern, ii. 862. characters of the sub-tribe, ii. 862. Cyclidmidtz (disk animalcules), a family of Polygastric Animals, iv. 4. characters of the'family, iv. 4. Cyctobranchiatn, ii. 379. See GASTEROPODA. Cyclodus nigroluteus, teeth of, iv. 891. (Jycloglena, a genus of Rotifera, iv. 404. L'yclopia, iv. 94J. 958. 9'7. Ci/clopian, or Cyclocephalian, monsters, congenital defect of the nos'e in, iii. 737. optic nerves in human cyclopian monsters, iii. 777. abnormal conditions of the brain in. iii. 719. 770 GENERAL INDEX. Cyclostomata, an order of Fishes, iii. 9">7, ct scq. characters of the order, iii. 9/>7. nervous system of the, iii. 614. Cydippe pileus, the, iii. 533. organs of locomotion in, i. 39, 40. Cydonium Mulleri, a genus of polyp, iv. 19. Cylindrical eye, iv. 1467. method of detecting the defect, iv. 14G8, 1469. Professor Stokcs's astigmatic lens, iv. 14G8. treatment, iv. 1469. fibro-cartilages, i. 249. Cylindrosoma, a genus of Myriapoda, iii. 546, et seq. Cynanche maligna, iii. 118. 120, 121. anasarca consequent upon, iii. 118. parotidea, or mumps, iv. 430. Cyninideet or gall-flies, ii. 866. habits of the, ii. 866. Cynocephalus (baboon), a genus of Quadrumana, iv. 197, et seq. See QUADRUMANA. characters of the genus, iv. 197. Cynthia, a genus of Tunicata. iv. 1 187, et seq. characters of the genus, iv. 1187. nervous system of the, iii. 603. Cynthia Dione, i. 112. Cyphonautes, a genus of Rotifera, iv. 402. Cyprinidce, a family of Fishes, iii. 957. dental apparatus of. iii. 979. Cyst, i. 787. definition, i. 787. development, i. 790. first class of cysts, i. 788. second class of cysts, i. 789. See also ADHESION. Cyst worms. See ENTOZOA ; Sterehnintha. Cystic artery, i. 195. duct, iii. 164. oxide, method of determining the presence of, in inor- ganic substances, iii. 805. tumours of pancreas, s. 110. Cystica, an order of Entozoa of Rudolphi, ii, 115. See EN- TOZOA ; Sterehnintha. Ci/sticercus cellulosae (Hydatis Finna of Rudolphi), an entozoon of the human muscles, ii. 118, 119. 127. 131. case of one found in the anterior chamber of the eye, ii. 119. and in the brain, iii. 720 E. fasciolaris in the river of rats, ii. 115. no nervous system discovered in the, iii. 607. mode of reproduction of, s. 26. Cystin. or cystic oxide calculus, iv. 70. deposit of, in urine in disease, iv. 1283. Cystingia, a genus of Tunicata, iv. 1188, et seq. characters of the genus, iv. 1188. Cyslis fellea. See G«//-bladder. Cystitis, acute, i. 397- characters of the urine in, iv. 1292. Cytoblastemal formations, iv. 100. See PRODUCTS, ADVEN- TITIOUS. Cystocele, i. 395. Cystoma. See Pseudo-tissues, serous. Cysts, or saccular adventitious serous tissue, iv. 140. primary cysts, iv. 140. simple, iv. 140. compound (cystoma), iv. 140. secondary, iv. 141. attached to the Fallopian tube, s. 620. in mammae, development of, iii. 253. operation for the removal of, iii. 253. of ovary, s. 578. simple, s. 578. multiple, s. 579. muliilocular, compound, or proliferous cysts, s. 580. contents of ovarian cysts, s. 582. fluid contents of cysts, s. 582. quantity of fluids and rate of effusion, s. 582. composition of the fluid contained in ovarian cysts, s. 583. hydatids contained in ovarian cysts, s. 584. solid contents of ovarian cysts ; sebaceous and su- doriparous glands ; fat ; hair ; teeth ; true bone, iv. 143; s. 584. origin of the solid contents of cysts, s. 585. foetus contained in the ovary (?) ; ovarian gesta- tion ; gravitas ovaria, s. 586. examples of supposed ovarian gestation, s. 587. origin of ovarian cysts in general, s. 590. cystic disease of the prostatic gland, iv. 157. of the serous membranes, iv. 538. serous, in the heart, ii. 645. in the cortical portion of the kidney, iv. 260. in the substance of the testicle, iv. 1010. in thyroid gland, iv. 1116. of the tongue, iv. 1157. of the urinary bladder, i. 393. D. Dacryoliths, or lachrymal calculi, iv. 82. example of the formation of, iv. 82. Dactyiopterus, or flying fish, mode of flight of the, iii. 429. Dahomans, physical and mental characters of the, iv. 13.K3. Daltonism, iv. 1452. See Achromatopsy ; VISION. Dancing, injuries of the tendons of the leg caused by, iii. 13'A Daphnidce, ovum of, s. [116.] [127.] Darien, Isthmus of, Albinoes of the, i. 84. Darkling-beetle (Blaps mortisaga), ii. 8G3. Dattos, or tunica, scroti, iv. 438. 0*6. Dasyprocta, or agouti, anatomy of the, iv. 373, et seq. Das'i/pus longicaudus, or armadillo, s. 163. Dasyurus, a genus of Marsupialia, iii. 259, et seq. characters of the genus, iii. 259. species of, iii. 259. Dasyurus ursinus, or " devil" of Van Diemen's Land, iii. 259. pelvis of the, s. 160, 161. Dauw, or onagga (Equus montanus), iv. 714. Day-fliers, or butterflies, ii. 866. Dawamesc, intoxicating effects of, iv. 690. Deafness, caused by a stoppage either in, or at the ex- tremity of, the Eustachian tube, ii. 576. caused by the destruction of the stapes and its at- tached membrane, ii. 576. DEATH, i. 123. 791. definition, i. 791. molecular death, i. 791 ; iii. 153. irritability, extinction of, i. 793. nutrition, arrest of the fluid of, i. 792. depravation of the fluid of, i. 7'J2. tissues, destruction of the, i. 791. retention of fluid in the, i. 792. systemic death, i. 794. syncope, by age, old, i. 798. See also AGE. by asphyxia, i. 794. See ASPHYXIA. by cold and lightning, i. 797. by disease, i. 797. by haemorrhage, i. 796. by injuries of the heart and of other organs, i. 796. by inanition, i. 797. by mental emotion, i. 796. by nervous lesion, i. 794. See also ASPHYXIA ; SYMPATHY. by poisons, i. 797. signs of approaching death, i. 798. circulation, decline of the, i. 801. death-struggle, or agony, i. 800. delirium, i. 799. facies Hippocratica, i. 802. heat, loss of, i. 801. muscles, relaxation of the, 5. 800. respiration, state of the, i. 801. secretion, state of the, i. 801. voice, weakness of the, i. 800. signs of actual death, i. 803. changes in the external appearance of the body, i. 807. appearance of the hands, i. SOS. lividities of the surface, i. 808. rosy hue of the cheeks, i. 807. state of the eyes, i. 807. changes in the tis'sues, i. 804. putrefaction, i. 807. sphacelus, i. 807. extinction of the vital functions, i. 803. time elapsed since death, knowledge derivable from the state of the body respecting the, i. 808. mean age at, iv. 1470. Death-rattle, i. 801. Death-struggle, or agony, as a sign of approaching death, Death-walches (Ptinidee), ii. 862. their ravages in houses, ii. 862. Decapoda, nervous system of the, iii. 609. organs and mode of locomotion of the, on solids, iii. 43G. 444. Decay of animal structures, iv. 456. periodical decomposition, iv. 456. carbonic acid the first product of animal decay, iv. 456. removed from living bodies by the lungs "and skin, iv. 456. water removed by the skin, iv. 456. nitrogen thrown off by decaying bodies, iv. 456. hydrocarbon of biliary secretion, iv. 458. nature of fascal matter, iv. 458. Decay of man, i. 77. Decidua, ii. 455. 457. Dccidua reflexa, or decidua chordii or ovuli, s. 653, 654. vera, decidua uteri, or parietal decidua, s. 653. histiology of the decidua, s. 653. relations of, to the villi, within the placenta, s. 719, development, s. 719, 720. serotina, s. 656. Deer, anatomical characters of, s. 508, et seq. connexion of the generative function with the annual shedding of the horns, ii. 443. horns of, s. 517. development of s. 517, 518. legs of, s. 521. organs of locomotion rf the, iii. -454. speed of the, iii. 454. pelvis of, s. 157. GENERAL IN7DEX. 771 Deer _ contnuteil. skeleton of the, s. f>07. skull of, s. 511. Weberian organ of the, iv. 1421. 142«. Deer, red (Cervus elephas), calculus of the— " deer's trars," IT. 82, Defalcation, ii. 20 ; s. 370. agents of the process of, iii. 721 L ; s. 370. offices of the muscles of the anus in performing the act of, i. 1«0. part taken by the abdominal muscles in aiding, i. 16, 17. sketch of the phenomena of, s. 371. the Iteces, s. 372. See F&ccs. condition of, during the sleep of hibernating animals, ii. 708. 772. Defecation of hair, iv. 142. Defloration of a virgin during ordinary sleep, iv. 682. Deformity, congenital. See TERATOLOGY. Deglutition, process of, ii. 8; iii. 760 ; s. 311. 398. analysis of the act of, iii. 721 I. exciting cause in the movements of, iii. 722 K. function o! the pharyax, mouth, and palate, in deglu- tition, iii. 953. function of the oesophagus in, iii. 759. involuntary nervous action in, iii. 589. uses of the salivary glands in, iv. 4'<>9. functions of the tongue in, iv. 1152. lirst stage : oral, iv. 1152. second stage : pharyngeal, iv. 1152. third stage : cesophageal, iv. 1153. difficult cases of deglutition, iii. 119, 120. Dt'ilt-pliila Elpenor, or Elephant sphinx, ii. 867. Deirodon, teeth of the, iv. 88G. ' Delirium preceding death, i. 799. phenomenon of, iii. 722 Y, 723 B. tremens, iii. 720. visual conceptions in, i. 800. characters of the urine in, iv. 1291. Drlvhinidce, family of, i. 563. Deltoid fossa, i. 216. impression, iv. 571. ligament, i. 152. muscle, i. 216, 217- 359; ii. 159, 160; iv. 435, 571. nerves, iv. 760. ridge of humerus, ii. 159, 169. Dementia, iv. 686. preceding death, i. 709. Dendrodoa, a genus of Tunicata, iv. 1187, el seq. characters of the genus, iv. 1 187. Dcndrodus, teeth of, iv. 869. Dental, or maxillary, artery, i. 489. inferior, ii. 227. superior, ii. 227 canal, inferior, ii. 214, 215. lower, ii. 214. foramina, posterior, ii. 208. superior, ii. 2H. nerve, inferior, ii. 29-'. 294. course, ii. 294. posterior superior, ii. 289. anterior superior, ii. 289. vein, inferior, iv. 14''5. system (in comparative anatomy). See TKETH. Dent'ate body, iii. GD2. fascia, ii';. 675. Dentated ligament (serrated membrane of Gordon), iii. 645. office of the, iii. 645. Dentine, iv. 864, 86\ De7ite$ scalprarii of Rodentia, iv. 368. 382. Deposition, excessive, of fat, i. 62. Deposits, or non-stromal formations, iv. 103. See PRO- DUCTS, ADVENTITIOUS. abnormal, in mucous membrane of the liver, iii. 183. in absorbent vessels, iii. 233. tubercle, iii. 233. cancer, melanosis, and encephaloid matter, iii. 233. calcareous and carbonaceous deposits, iii. 23l. adventitious, on the heart, ii. 041. atheromatous, in veins, iv. 1402. Depressor alae nasi (musculus myrtiformis), ii. 223 ; iii. m. relations and action, iii. 7^. anguli oris muscle, ii '22"). relations and action, ii. 225. labii inferiors muscle, ii. 22*. relations and action, ii. 225. septi narium muscle, iii. 729. relation and actions, iii. 729. urethrae muscle, iv. 1'264. Derbesia. mode of reproduction of, s. 214. Dermal system of Amphibia, i. 102. Dermaptera, an order of Insecta, ii. S'>3. characters of the order, ii. 863. mode of flight of the, iii. 421. Dermapterygii, a division of Fishes, iii. 957, et seq. characters of the division, iii. 957. Des Cartes, his theory of the chief source of nervous power, iii. 677. Descendens noni nerfe, iii. 721 ; iv. 754. DetmidicE, mode of reproduction of, s. 218. Desiccation of organic substances, iii. 793. method of per'orming, iii. 79?, 794. apparatus for desiccation of organic substances, iii. 813. Dclrusor urinae muscle, i. 381 ; iv. 1263. Devil of Van Diemen's Land (Dasyurus ursinus), iii. 259. Diabetes mellitus, iv. 97. specific gravity of the blood in, i. 416. state of the blood m, i. 427. effects of diabetes on the circulation, i. 793. fatty degeneration of pancreas in cases of diabetes, s. 111. characters of the urine in diabetes mellitus, insi- pidus, and chylosus, iv. 1293. saccharine, iv. 99. theories of the pathology of, iv. 99. Diamond, composition of the, iv. 1438. Diaphoretics, effects of, on animal heat, ii. 682. DIAPHRAGM (in anatomy generally), ii. 1. definition, i. 2 ; ii. 1. DIAPHRAGM (in human anatomy), ii. 1. form, structure, and organisation, ii. 2. arteries, ii. 4. muscles, ii. 2; iii. 544. costal, upper, true, or greater, ii. 2. centrum tend ineum, cord i form tendon, ii. 2. ligamentum arcuatum externum. ii. 3. internum, ii. 3. septum transversum, ii. 2. vertebral, or smaller muscle.-— crura, pillars, or appendices, ii. 3. foramina, or openings, ii.3. foramen aorticum, ii. 3. quadratum s. venosum, ii. 3. other smaller foramina, ii. 4. lymphatics, ii. 4. nerves, ii. 4. •• peritoneum lining the, i. 14. peritoneal investment of the under surface of the diaphragm, iii, 944. pleura diap*>ragmatica, iv. 2. relations to the pleura, peritoneum, &c., ii. 4. veins, ii. 4. malformations and diseases, ii. 6. absence, ii. 6. cartilaginous and osseous deposits, ii. 6. displacement from ascites, &c. ii. 6. gangrene, collection of pus, tumours, &c., ii. 6. inflammation, ii. 6. openings, ii. 6. rupture,— risus Sardonicus, ii. 6. ulcers, ii. 6. wounds, ii. 6. uses of the diaphragm, ii. 4. part performed by the, in respiration, iv. 32-1. 1081. congenital perforation of the, i. 508. Diaphragmatic hernia of foetus in utero, ii. 319. Diaphragmatic nerve, iv. 754. plexuses of nerves, right, s. 428. left, s. 428. Diaphragmitis, ii. 6. Diarrhoea, syncope from, i. 797. colliquative, occurrence of, in animals reduced by star- vation, iii. 752. Diarthrodial cartilage, i. 248. 255. See ARTICULATION. Diarthrosis, class of articulations, i. 2o5. arthrodia, i. 256. enarthrosis, i. 256. ginglymus, i. 256. rotatoria, i. 256. synarthrodica, form of articulation, i. 255. Diastase, process of, iii. 153 ; s. 105. natural and artificial conversion of gum, starch, and lignin into sugar, iii. 153. Diastole, or relaxation, of the heart's auricles and ventri- cles, ii. 602 — 604. See HEART, PHYSIOLOGY OF. Diazona, a genus of Tunicata, iv. 1 190, et seq. characters of the genus, iv. 1190. Dibranchiata, i. 519. characters of the order, i. 519.* Dichitonida, a sub-class of Tunicata, iv. 1 186, et seq. characters of, iv. 1186. families of, iv. 1187, et seq. Dichobune, an extinct genus of Pachydermata, which see. Dicotyles, anatomy of the. See PACHYDERM ATA. Dictyotacea: , mode of reproduction of the, s. 216. Dicynodon lacerticeps, skull of, iv. 889. Didelphys, a genus of Marsupialia (opossums), iii. 261 el seq. characters of the genus, iii. 261 . species of, iii. 261. Didelphys cancrivora, iii. 261. opossum, organs of voice of, iv. 1491. cynocephalus, or hyaena of Van Diemen's Land, iii. 258, et seq. Virginiana, iii, 261. Didemnina, a tribe of Tunicata, iv. 1190. genera, iv. 1190, 1191. characters of the tribe, iv. 1 190. Didemnum, a genus of Tunicata, iv. 1190, et seq. characters of the genus, iv. 1 190. Didus ineptus (dodo), account of the, i. 269. 772 GENERAL INDEX. Diet and regimen, effect of, on the evolution of animal hoar, ii. 682. Dietaries, observations on, s. 396. quantity of food required per diem, 8. 397. Digastric muscle, iii. 105. 563. action and relations, iii. 563, 564. nerve, iii. 949; iv. 547. space, iii. 564. 570. 581. anterior division, iii. 581. posterior division, iii, 581. sulcus, i. 734. DIGESTION, ii. 6. definition, ii. 6. I. description of the organs of digestion, ii. 7. mouth, with Us appendages, ii. 8. lips, ii. 8. salivary glands, ii. 8. teeth, ii. 8. oesophagus and deglutition, ii. 8. stomach and intestinal canal, ii. 9, 10. movements of the stomach at the commence- ment of, s. 312. a. when a large quantity of fond is hastily swallowed without mastication, s. 31'2. b. when a small quantity of liquid food is taken, s. 312. c. when in the ordinary state of moderate distension, with food properly prepared by mastication, s. 313. movements of the stomach in the later stages of digestion, s. 314 changes in the stomach during digestion, s. 328. gastric juice, s. 328. physical properties, s. 329. specific gravity, s. 329. quantity, s. 330. chemical composition, s. 330. action, s. 333. process of secretion, s. 337. changes in the villi of the intestine during di- gestion, s. 355. theories of the process of stomach digestion, s. 336, 337. peculiarities of the digestive organs in different classes of animals, ii. 11. II. nature of the substances usually employed as food, ii.12. animal compounds, ii. 13. eggs, fish, flesh, milk, and soups, ii. 13. condiments, — salts and spices, ii. 15. liquids, ii. 14, 15. medicaments, ii. 15. vegetable substances, ii. 13. farina and gluten, ii. 13. III. changes which the food experiences in the process of digestion, ii. 15 ; iii. 743. chyme, properties of, ii. 16. process of chymification, ii. 16. 25. chyle, analysis of, ii. 19. 20. process of chylification, ii. 19. 25 ; iii. 745. gastric juice, physical and chemical properties of, IV. theory of digestion, ii. 21. hypothesis of chemical solution, ii. 22. fermentation, ii. 22. nervous energy, ii. 23. trituration, ii. 22. vital principle, ii. 23. V. affections pecuhar to, or dependent upon, the functions of the digestive organs, ii. 25. hunger, ii. 25. nausea, ii. 26. thirst, ii. 25. relations of digestion to nutrition generally, s. 397. prehension, s. 397. mastication and insalivation, s. 397. deglutition, s. 398. gastric digestion, s. 398. intestinal digestion, s. 398. the bile, s. 399. pffects of the lesion of the vagi upon the function of, iii. 900. effects of digestion on the quantity of carbonic acid gas in the expired air, iv. 346. organs of digestion in infancy, i. 67. condition of the powers of, in hibernating animals, ii. See also NUTRITION. animal and vegetable digestion compared, i. 132. DIGESTIVE CANAL (in comparative anatomy), ii. 27. See the various classes of Animals, under tlu-ir head- ings. Digi al arteries, iv. 226. 1407. cavity, or fossa trochanterica. ii. 166 ; iii. 674. nerves, iii. 904. first, iv. 7*7. second, iv. 757. third, iv. 757. fourth, iv. 757. fifth, iv. 757. terminal, iv. 757. Digitalis, action of, on the vital power of the heart, i. 723. 797 -D/gto" pedis, toe bones, ii. 342. Diglena, a genus of Kotifera, iv. 404. Diglena lacustris, digestive organs of the, s. 2'.T>. Dilatation of the cavities of the heart, ii. 640. of the orifices of the heart, ii. 640. of the valves of the heart, ii. 647. of arteries, i. 235. Dilator narium anterior muscle, iii. 729. posterior, iii. 729. Dimensions of objects, power of judging correctly of the, at a distance, iv. 144(5. instance of Napoleon Bonaparte, iv. 144'!. Dimyaria, i. 695. See CONCHIFERA. Dingo, or wild dog of Australasia, iii. 257, note ; iv. 1305. 1307. Dinobryna, a family of Polygastric Animals, iv. 4. Dinocharis, a genus of Ilotifera, iv. 406. paupera, iv. 412. Dinornis, pelvis of the, s. 168. Dinothenum, anatomy of the. See PACHYDERMATA. teeth oftha, iv. 931. Diodons, mode of progression of the, iii. 437. teeth of, iii. 980. Dioecious reproduction, or generation with d;stinct indi- viduals of different sexes, ii. 435. See (.JKNEKATION. Dioptric phenomena, iv. 1440. Diptitherite of M. Bretonneau, iii. 117. symptoms and appearances of, iii. 117. sloughing, iii. 118. differences between it and croup, iii. 118. diphtheritic deposit, iv. 118. white thrush, iv. 118. white cheesy substance, which forms on blistered surfaces, iv. 118. Di-Ityda (Acalephse), i. 36. Dipliycs campanulifera, i. 33. Diplue, condition of, in erysipelas, i. 745. DIPLOGENESIS, i. 509. Diploic plexuses of vein?, iv. 1388. Diplostomum volvens, an Entozoon infesting the eyes of animals, ii. 121, 122. 132. organs of digestion of the, s. 296. Diploxoon paradoxum, ii. 132. mode of reproduction of the, s. 32. Diptera, an order of Insecta, ii. 867. characters of the order, ii. 867. families, ii. 867- wings of the, iii. 423. powers of flight of the, iii. 423. ovum and micropyle of, s. [1 12]. Dipus hersipes, or jerboa, anatomy of the, iv. 309, et seq. Direction, sense of, of some animals, iv. 702. Disarticulations of hand, ii. 529- Discoboli, a family of Fishes, iii. 957. Discomycetes, reproductive system of the, s. 226. Dislocations of the several joints. See under the heading of each. Disoma, or double-bodied animalcule, iv. 12. Dissection, microscopic, iii. 346. best means for carrying on dissections under amagnify- ing power, iii. 346. instruments for microscopic dissection, iii. 316. Svvammerdam's implements, iii. 347. compressorium, iii. 347. Dissection of urethra, iii. 926. See URETHRA. effects of wounds received in, i. 362. Distemma, a genus of Kotifera, iv. 404. Distoma (flukes), doubtful existence of muscle and nerve in the, iii. 534. digestive organs of the, s. 296. mode of reproduction of, s. 30. armatum, a parasitic worm, ii. 127. clavatum, ii. 126. 128. 132. denticulatum, ii. 127. ferox, ii. 127. hepaticum (or liver-fluke), description of the, ii. 12. 132. in veins, iv. 1402. nervous system of the, iii. 607. hians, development of the young of, ii. 143. perlatum, a parasitic worm, ii. 127. generative organs of, ii. 138. spinulosa, a parasitic worm, ii. 127. trigonocephalum, a parasitic worm, ii. 127. Distomus, a genus of Tunicata, iv. 1190, et seq. characters of the genus, iv. 1190. Dfurna, day-fliers or butterflies, a section of Insects of the order Lepidoptera, ii. 866. characters of the section, ii. 866. Diversities of mankind, iv. 1315. See VARIETIES OF MAN- KIND. Diverlicula of intestinal canal, s. 404. /Jf'wmg-bell, distressing tension of the tympanum when in the, ii. 575. relief obtained by the act of swallowing, ii. f>75. of the water spider, iii. 9. Dodo (Didus ineptus), account of the, i. 269. Dog, brain of the, iii. 696. actions of, in which short processes of reasoning seem to have been concerned, iii. 22. GENERAL INDEX. 773 Dvg — continued. dentition of the, iv. 907. 009. organs of voice of the, iv. 1490. prolonged coition of the, iv. 1435. spermatozoa of the dog, iv. 477. differences between wild and domesticated dogs, iv. 1307. barking, iv. 1307. dingo, orwilddogof Australasia, iii. 257. note i\\. 1"05. 1307. Newfoundland dog, feet and organs of locomotion in water, iii. 439. Doz-fish ( Spinax acanthias), sexual organs of the female, iii. 10t'9. Dolphin, cardiac pericardium of the, i. 57. DomeftfctUion of animals, tendency to variation in, iv. 1304. D«ndos. See ALBINO. Dormant vitality, iii. 141. 154. See LIFE, VITALITY, DOR. M \XT Dormouse (Myoxus), anatomy of the, iv. 376. ct scq. ili-iestive organs of the, s. 303. hibernation of the. See HIBERNATION. I) .>rsal arteries of clitoris, s. 709. 713. artery of penis, iii. 917 ; iv. 1254. of tongue, iv. 1 141. of the foot, ii. 352. ligaments. See Ligaments. of tarsus, ii. 343. nerve, first, anterior branches of, iv. 754. (intercostal), iv. 760. cutaneous branches, iv. 760. intercostal branches, iv. 760. special characters of, iv. 760. internal, iv. 758. of penis, iii. 918; iv. 766. veins of clitoris, s. 7. anterior, lateral, and posterior surfaces, ii. 63. aponeurosis, ii. 64. brachial artery, ii G«. See BRACHIAL ARTERY. development, ii. f>4. lymphatic vessels, ii. G4. n'.-rves, subcutaneous, ii. 64. skin and subcutaneous tissue, ii. 63. varieties, ii. 65. veins, ii. yy(iXeu of Aristotle, ii. 111. NTOZOA. Elminthoida, i. 245. Emasculation. See Castration. Embryo-ce}\, s. 4. See OVUM. -genesis, s. 4. Embryology. See Ovt M. Eminence, ilio-pectineal, s. 115. thenar, ii. 358. articnlaris, i. 734. carpi radialis superior, ii. ft05. interior, ii. 50*5. ulnaris superior, ii. M)5. inferior, ii. 506. capitata, ii. 65. frontalis, i. 729. pyramidalis, ii. 530. natifoimes, iii. 677. testiformos, iii. 677. papillatis s. protuberantia pyramidalis, ii. 544. Emotion, considered as a mental nervous action, iii. 589. influence of, on the body. iii. 711. Emotional e\c\ttment, part of the brain most directly in- fluenced by, iii. 7 '22 P. Emjhysema, i. 516 ; iii. 82. 85. of the lungs, associated with bronchitic collapse, s. 292. mechanism of emphysema, s. 293. Emvyema, characters of the urine in, iv. 1291. Emulgent, or renal, arteries, i. 223 ; iv. 235. vein, iv. 23G. 238. Enaliosaurs, teeth of, iv. 895. Enantiotreta, a section of Polygastric Animals, iv. 5. Enarthro^is, or ball and socket joint, i. 251. 256. Encaustum, or enamel of teeth, iv. 865. Encephalic nerves, iii. 629. 707. Encejthalitis, characters of the urine in, iv. 1291. Encephalocele, or hernia cerebri, i. 744; iii. 7 19; iv.954. 956 hydro-encephalocele, iy. 956. nf the foetus in utero, ii. 320. Encephaloid cancer, characters of, iv. 137. of the lungs, s. -J93. of the testicle, iv. 1010. of thyroid gland, iv. 11 10. tumours in the muscular si substance of the heart, ii. 637. matter of absorbent glands, iii. 234. Encephalon, or brain, iii. 661 ; iv. 677. size compared with that of the body in different animals, iii. 661. compared with that of the encephalic nerves, iii. 662. weight of the human encephalon, iii. 662. table showing the absolute average weight of the human encephalon, in males and females, iii. 662. table showing the relative weight of encephalon to cerebellum, &c., in males and females, iii. G*J3. table showing the relative weight of entire body to encephalun, cerebrum, cerebellum, &c., iii. 663. conclusions, iii. 664. absolute weight of the brain of the elephant and whale, iii. 664. weight of brain of some animals greater than that of man, relatively to the weight of their bodies iii. 664. conclusions of Tiedeman deduced from his obser- vations, iii. 664. remarks on the comparison of the brr.in of man with that of the lower animals, iii. 664. the brain in different races of mankind, iii. 665.a conclusions, iii. 667. method of examining the brain, iii. 667 668. method of Willis, iii. 668. method of Reil, Gall, and Spurzheim, iii. 669. Surface of the encephalon, iii. 670. shape of the brain, iii. 670. superior and lateral surfaces, iii. 670. base of the brain, iii. 670. anterior segment,— olfactory sulcus, iii. 670. fissure of Sylvius,— locus perforatus anti- cus, island of Reil, iii. 671, 672. middle segment, iii. 672. pituitary process, tuber cinereum, iii. 673. optic tracts, and optic commissure, iii. 673. corpora albicantia, iii. 673. crura cerebri, intercrural space, substantia perforata, pons Tarini, iii. 673. transverse or horizontal fissure, iii. 673. circle of Willis, iii. 673. posterior segment, iii. 673. dissection of the brain from above downwards, iii. 674. centrum ovale majus and minus, iii. 674. corpus callosum, longitudinal tracts, iii. 674. lateral ventricles, iii. 674. septum lucidum, iii. 674. parts seen in the lateral ventricles, iii. 675. fifth ventricle, iii. 674. fornix, iii. 675. third ventricle, Hi. 676. anterior commissure, iii. 677. pineal gland, iii. 677. soft commissure, iii. 677. mesocephale, iii. 677. corpora quadrigemina, iii. 677. pons Varolii, iii. 678. processus cerebelli ad testes, iii. 677. valve of Vieussens, iii. 678. cerebellum, iii. 678. fourth ventricle, iii. 678. Examination of the various segments of the encephalon, with a more special reference to the structure and physiological bearing of each, iii. 678. Medulla oblongata, iii. 678. columns, anterior pyramidal, iii. 679. 684. olivary, iii. 679. 683. 684. corpus dentatum, iii. 683. posterior pyramidal, iii. 679. 682. course of fibres, iii. 680. restiform, iii. 679. 682. 684. interpretation of the various columns, iii. 684. definition, iii. 679. development, iii. 683. fibres of, antero-posterior, iii. 680. arcifonn, iii. 680. decussating, iii. 680. 776 GENERAL INDEX. Encephalun : Medulla oblongata — continued. fissure of, median anterior, iii. 679. posterior, iii. 679. nerves connected with the medulla oblongata, iii. 684. shape of medulla oblongata, iii. 684. transverse sections of the medulla oblongata, iii. 683. Mesocephale, or mesencpphale, iii. 684. corpora quadrigemina, iii. 685. pons Varolii, iii. 685. processus cerebelli ad testes, iii. 686. valve of Vieussens, iii. 686. conclusions, iii. 686. Cerebellum, iii. 687. arbor vitas, lateral and median, iii. 692. castration, alleged effects of, on the cerebellum, iii. 687. commissures, iii. 691. long and hidden, iii. 691. short and exposed, iii. 691. single, iii. 691. corpus dentatum, or rhomboideum, iii. 692. cms certbelli, iii. 692. peduncles of, iii. 693. inferior, iii. 693. middle, iii. 693. supeiior, — proccssus cerebelli ad testes, or cerebro-cerebellar com- missures, iii. 693. development of the cerebellum, iii. 687. relative development of cerebellum to cerebrum in the adult, iii. 687. fissures, i;i, 687. horizontal, iii. 688. purse-like fissures, or posterior not;h, iii. 688. semi-lunar, iii. 687. valley, iii. 687. lamina, iii. 689- 691. lobes and lobules, iii. 689. amygdala, iii. 689. 692. biventral, iii. 689. 692. median, iii. 689. posterior, iii. 689. 692. pyramid of Reil, iii. 691. uses, iii. 691. posterior superior, iii. 689. 692. slender, iii. 689. spigot of Reil, iii. 691. 692. uses, iii. 691. square lobe, iii. 689. 691. nodule, iii. 690. 693. shape of the cerebellum, iii. 687. sections of the cerebellum, iii. 692. horizontal, iii, 692. vertical, iii. 692. size and weight of the cerebellum, iii. 687. subdivisions into median lobe and lateral lobes or hemispheres, iii. 687. surfaces inferior, iii. 689. 691. superior, iii. 689, 690. tentorium cerebelli, iii. 687. velum, posterior medullary, iii. 690. ventricle, fourth, iii. 693. aqueductus Sylvii, iii. 693. calamus scriptorius, iii. 693. choroid plexuses of the fourth ventricle, iii. 693. vermiform process, inferior, iii. 687. superior, iii. 687. white and grey matter, iii. 692. sketch of the microscopic anatomy of the encephalon, iii. 707. medulla oblongata, iii. 703. mesocephale. iii. 709. cerebrum and cerebellum, iii. 709. brief statement of the probable modus operandi of the brain, iii. 710. Abnormal anatomy of the brain and its membranes, iii. membranes, iii. 715. dura mater, iii. .715. general or partial deficiency, iii. 715. acute disease, iii. 715. causes, iii. 715. treatment, iii. 715. adhesion to the cranium, iii. 715. cancer, iii. 715. effusion of blood, iii. 716. fibrous tumours, iii. 715. fungus of the dura mater, iii. 716. patches of bone in the processes of the dura mater, iii. 715, arachnoid, iii. 716. acute inflammation, iii. 716. opaque condition of the arachnoid, iii. 716. causes of opacity, iii. 716. adhesion, iii. 716. deposits of bone on cartilage, iii. 716. Enccphiilou — continued. effusions into the sub-arachnoid and arachnoid cavities, iii. 716. of serum, iii. 716. of blood, iii. 717. of pus, iii. 717. brain, abnormal conditions of the, iii. 718. congenital abnormal conditions, iii. 718. absence of the brain, iii. 718. brain of idiots, iii. 718. changes which take place in, iii. 719. fusion of the hemispheres, iii. 719. absence of the transverse commissures, iii. 719. acquired or morbid conditions, iii. 719. hypertrophy, iii. 719. cases recorded, iii. 720. parts of the brain affected, iii. 720. atrophy, iii. 720. softening, iii. 720 A. white softening, iii. 720 A. red softening, iii. 720 B j 721 G. suppuration, iii. 720 B. hyperaemia, iii. 720 C. active and passive, iii. 720 C. causes, iii. 720 C. anaemia, iii. 720 C. cerebral haemorrhage, iii. 720 D. apoplexy, cerebral, iii. 720 D. capillary, iii. 720 D. cancer of the brain, iii. 7^0 E. seat of the disease, iii. 720 E. origin and progress, iii. 720 E. fungoid and hard tumours of the brain, iii. 720 E. tubercle of the brain, iii. 720 E. anatomical characters of, iii. 720 E. parts most frequently affected by, iii. 720 E. entozoa in the brain, iii. 720 E. morbid states of the ventricles, iii. 720 E. dilatation, iii. 720 E. colour of the fluid contained in, iii. 720 E. choroid plexus, deposit of lymph on, iii. 720 F. earthy concretions in, iii. 720 F. vesicles in, formerly regarded as hydatids, iii. 720 F. Functions of the encephalon, iii. 722 I. of the medulla oblongata, iii. 722 I. corpora striata, iii. 722 L. locus niger, iii. 722 M. optic thalami, iii. 722 M. corpora quadrigemina, iii. 722 O. olivary bodies, iii. 722 O. flocks of Reil, 722 O. mesocephale, iii. 722 P. emotion, iii. 722 P. diseases connected with disturbed state of emotion, iii. 722 O. may be regarded as the centre of emotional actions, iii. 722 Q. of the cerebellum, iii. 722 Q. co-ordination of movements, iii. 722 R. Gall's views, — connexion of the cerebellum with the sexual functions, iii. 722 S. of the cerebral convolutions, iii. 722 X. Dr. Wigan's doctrine of the duality of the mind, iii. 722 Z. sensation, iii. 723 A. volition and attention, iii. 723 A sleep, iii. 723 B. dreaming, iii. 723 B. coma, iii. 723 B. somnambulism, iii. 723 B. delirium, iii. 723 B. fibres of the centrum ovale, iii. 723 B. of the commissures, iii. 723 D. corpus caJosum, iii. 723. fornix, iii. 723 D. pons Varolii, iii. 723 E. summary of the physiology of the encephalon, iii. 723 E. Encephalosrs, or medullary sarcoma of the liver, iii. 193. Enccphalous Mollusca, iii. 364. See MOLLUSCA. Encheliadee (rolling animalcules), a family of Polygastiic Animals, iv. 4. characters of the family, iv. 4. Enchelis, or revolving animalcule, iv. 12. Enchondroma, iv. 132. 139, 140. form and colour, iv. 133. progress of, iv. 134. Encn'nus, the, iii. 537. muscular system of the, iii. 537. Encysted fatty matters, iv. 97. analysis of, iv. 97. Enderon, structure of the, s. 502. pigment of, s. 502. papillae of, s. 502. sensory appendages, s. 502. GENERAL INDEX. 777 Endcron — continued. corpuscula tactus, s. 503. Panician bodies [see also PANICIAN BODIES], s. 504. muscles of the, s. 505. calcareous deposits in the, s. 506. Endocarditis, course and termination of the disease, ii. 645, 646. Endocardium, morbid states of the, ii. 645. Endulymph, ii. 539. Endo-metritis, s. 694. 702. Endo-skelfton of Cephalopoda, i. 519. losis, ii.98. definition, ii. 98. measurement of the amount of, ii. 98. of the strength of, ii. 98. effects of temperature, ii. 100. explanation of the phenomena, ii, 100. circumstances in which endosmosis occurs, ii. 110. England, mean age at death of the population of, compared with that of America, iv. 1471. English language, method by which the relation between the different words that constitute sentences is indicated in the, iv. 1346. Ensiform cartilage, or xiphoid appendix, iv. 1023. Eiiterocele, ii. 738. ossification of the, iv. 1024. Enlcrodcla, a class of Polygastria, iv. 3, et sea. Entcro-epiplocele, ii. 738. EntcropUa, a genus of Rotifera, iv. 404. Entomuline, or chitine, ii. 881. chemical composition of, ii. 882. Entomophaga, a tribe of Marsupialia, iii. 259, et sea. characters of the tribe, iii. 259. genera of, iii. 260. Entoinostraca, ovum of, s. [116.] ENTOZOA (a class of Invertebrate Animals), i. 109 ; ii. 111. anatomy of the Entozoa, ii. 126. organs of circulation in, i. 654. digestive organs, ii. 131 : s. 295. accessory glands of, ii. 136. excretory glands, ii. 136. generation, organs of, ii. 137. 410. 431. mode of repr 'duction of the, s. 10, 11. 24. cystic Entozoa, s. 25. free tapeworms, s. 27. Trematoda, s. 29. ova of Entozoa, s. [120]. muscular system, ii. 127. nervous system, ii. 129; iii. 607. respiratory glands, ii. 136. tegumentary system, ii. 126. epidermic processes, or spines, ii. 127. Bibliog. and refer., ii. 144. definition, ii. 111. division into three classes, ii. 111. Protelmintha, ii. 111. Sterelmintha, ii. 111. Ccelelmintha, ii. 111. families of the first class, Protelmintha : — Cercariadae, ii. 111. Spermatozoa, ii. 111. 459. Trichina spiralis, ii. 113. Vibrionidae, ii. 113. families of the second class, Sterelmintha, equiva- lent to the orders of Rudolphi : — Cystica, ii. 115. Cestoidea, ii. 116. Trematoda, ii. 116. Acanthocephala, ii. 116. families of the third class, Ccelelmintha : — Acanthotheca, ii. 116. Nematoidea, ii. 116. description of Entozoa hominis belonging to the above orders, ii. 117. Acephalocystis endogena — Pill-box hydatid, ii. Ascaris lumbricoides, ii. 125. vermicularis, ii. 125. Bothriocephalus latus, ii. 120. Cysticercus cellulosa, ii. 118. Diplostomum volvens, ii. 121. Distoma hepaticum, ii. 121. Echinococcus hominis, i. 117. Filaria bronchialis, ii. 122. Medinensis, ii. 122. oculi humanis, ii. 122. Polystoma pinguicola, ii. 121. venarum, ii. 121. Spiroptera hominis, ii. 123. Strongylus gigas, ii. 125. Taenia solium, ii. 120. Trichocephalus dispar, ii. 122. geographical distribution of Entozoa hominis, ii. 120. tabular view of Entozoa hominis, ii. 126. found in the brain, iii. 7'20 E. existence of worms in the intestines of the foetus in utero, ii. 336. in the heart, ii. 647. acarus folliculorum, iii. 730. Gregarinae, process of reproduction in, s. 7. of the human liver, iii. 196. in veins, i". 1402. Sllpp. Soli's Farrani, biliary organs of, iv. 449. Eosphora, a genus of Rotifera, iv. 404. Ephemera, iii. 539. vulgata, or May-fly, ii. 864. Ephemeridce, or May-flies, ii. 864. characters of the, ii.864. Ephippial process, anterior, or anterior clinoid, i. 726. 728. Ephippfum, i. 726. Epicondyle of humerus, ii. 160. Epicranial aponeurosis, i. 748, 749. Epididymis, induration of the. iv. 712. encysted hydrocele of the, iv. 997, 998. epididymitis, iv. 1006. Epigastric artery, ii. 842. branches, ii. 843. origin and distribution, ii. 842, 843. internal, ii. 250. superficial, ii. 243. 250. pulsations, i. 504. enumeration of causes, i. 504. region, i. 502. solar, or cceliac, plexus of nerves, s. 428. veins, deep, iv. 1412. superficial, iv. 1411, 1412. Epigastrium, i. 4. Epigenesis, theory of, ii. 428. See GENERATION. . EmgloOfc gland, iii. 111. Epiglottis, the, iii. 103. foramina of the, iii. 103. ligaments of the, iii. 104. ligamentum thyro-epi»lottideum, iii. 104. hyo-epiglpttideum, iii. 104. glosso-epiglottideum, iii. 104. morbid aratomy and pathology of the epiglottis, iii. destruction of the, by ulceration, iii. 119. appearances after death, iii. 119. alterations in size and shape, iii. 122. morbid thickening or shrinking, iii. 122. leaf-like expansion, iii. 122. exceptions to the use of the epiglottis, iii. 122. epiglottis inert, iii. 123. condition of the epiglottis in an animal asphyxiated by carbonic acid, iii. 123. 125. influence of the, on the voice, iv. 1485. Epilepsy, cause of, i. 416. from affections of the brain, iii. 720. cause of the convulsions of, iii. 721 G. cerebral hyperaemia in cases of epilepsy, iii. 720 C. dilated state of the ventricles of the brain in old epi- leptics, iii. 720 E. Epiplocele, ii. 738. Epiploic veins, iv. 1414. EpipJoicte, appendices of the colon, i. 57. Epiploon, or great omentum, i 502. of Arachnida, uses of fatty globules in, i. 204. Epira diadema, nervous system of the, iii. 609. Epispadias, iv. 953. 1256. complication of, with ectrophy of the bladder, iv. 1256. Epithelium, iii. 489. definition, iii. 489. general remarks, iii 489. lamelliform, or scaly, variety of epithelium, iii. 489. prismatic, iii. 490. spheroidal, iii. 491. non-ciliated and ciliated particles, iii. 492. of the air-passages and cells of the lungs, s. 272. of the kidney, iv. 252. of the Malpighian bodies, iv. 252. of the uriniferous tubes, iv. 252. of pelvis and ureter, iv. 254. of the nose, iii. 730. of the trachea, s. 259. cilia of, s. 260. of veins, iv. 13R9. 1379. Epitricha, a section of Polygastric animals, iv. 5 Epitrochlea of humerus, ii. 160. Epnoa, or external parasites, mode of reproduction of the, s. 10. alimentary canal of the, s. 298. offhhes.ii. 116. Epu/is, iii. 954. Equilibrium of the body, power of maintaining the, iv. Equisetaceee, vegetative system of, s. 211. germination of the spore, s. 241. antheridium, s. 241. archegonium, s. 241. spores and sporangia, s. 242. Equus asinus, iv. 714. caballus, iv. 714. hemionus, iv. 714. montanus, iv. 714. quaccha, iv. 714. zebra, iv. 714. organs of voice of the genus Equus, iv. 1492. Erebus strix, mode of flight of the, iii. 422. Erect attitude, a distinctive characteristic of man, iii. 127 : iv. 1295. causes of this characteristic, iii. 127. 3 E 778 GENERAL INDEX, ERECTILE TISSUE, i. 243 ; ii. 141. definition, ii. 144. development in various parts of the animal economy, ii. 144, 145. 445, 446. penis, arteries and investing membrane of the, ii. 146. 445. tergor vitalis of Habenstreit, ii. 147. morbid development of erectile tissue, ii. 147. erectile growths, iv. 128. Erection of penis. See ERECTILE TISSUE ; GENERATION ; Erector penis muscle, ii. 446 ; iii. 915. 929 ; s. 138. Erectores clitoridis muscles, s. 138. 709. Erinaceadce, or hedgehog family, ii. 994. Erinaceus Europaeus, or hedgehog, ii. 996. See INSEC- TIVORA. organs of voice of the, iv. 1489. Erpobrtella, or leech, organs of circulation in the, i. 651. Eructation, or belching, s. 316. causes, s. 316. Eruptive diseases of the fetus in utero, ii. 333. Erysipelas of elbow, ii. 63. of the larynx, iii. 118. symptoms and appearances, iii. 118. invariably fatal termination, iii. 118. postmortem appearances, iii. 118. phlegmonous, of cellular tissue of the leg, iii. 128. Erythroprotid, iv. 164. Eschara, a genus of Polypifera, iv. 51. 54. cervicornis, iv. 51, 52. Esoctdce, a family of Fishes, iii. 957. Esculent vegetables considered as food, s. 395. composition of, s. 395. Esquimaux, cranium of, iv. 1325. 'ETtx,n>'iux,i of the Greeks, ii. 6S6. Ethal, chemical characters of, ii. 234. Ether, effect of the inhalation of, iv. 697. 1182. its peculiar influence upon the spinnl cord, iii. 721 H. and in controlling the effect produced by strych- nine, iii. 721 H. Ethiopians, capacity of the skull of, iii. 666. Ethmoid bone, i. 728, 729, 730 ; iii. 724, 725. articulations,}. 731. cells, i. 731. development, i. 731. Ethmoidal process, i. 728. arteries, iii. 786. posterior, i. 492. anterior, i. 492; iii. 733. branch of the fifth pair of nerves, iii. 733. cells, i. 731 ; iii. 724, 725. hiatus, i. 730. or internal, surface of lachrymal bone, ii. 212. processes, ii. 213. suture, i. 737. Euchlanidota, a family of Rotifera, iv. 405. characters of the family, iv. 405. genera, iv. 406. Euchlanis, a genus of Rotifera, iv. 406. triquetra, iv. 405. Euccelium, a genus of Tunicata, iv. 1190, et seq. characters of the genus, iv. 1190. Eudea, a family of Porifera, iy. 65. characters'of the family, iy. 65. Eudoxia, organs of digestion in, i. 41. Euglena viridis, s. 211. Eunuchs, excessive deposit of fat in, i. 62 ; ii. 718. their outward appearance after castration before and after puberty, iv. 985. Euplectella aspergillum, a species of Porifera, iv. 66. EuplotidcB (boat animalcules), a family of Polygastric animals, iv. 5. characters of the family, iii. 5. Eupoda, a sub-tribe of Insects of the order Coleoptera.ii. 862. characters of the sub-tribe, ii. 862. European races, principal characters of the, iv. 1348. cranium of Europeans, iv. 1323. 1325. Eustachian canal, i. 734. sulcus, i.727. tube, i. 734 ; ii. 549. cartilaginous and membranous part, ii. 550. osseous part, ii. 549. office of the, in the function of hearing, ii. 576. valve, ii, 580. lesser, or valve of Thebesius, iv. 1415. peculiarities of the, in the foetal heart, ii. 599. atrophy of the, ii. 647. Eustachius, vena alba thoracis of, iii. 206. Evaporation, influence of, upon the production of animal heat, ii. 661. Eventrativn, i. 508. Evolution, a theory of generation, ii. 428. See GENERATION. Evolution of heat. See HEAT, ANIMAL. Excito-motory phenomena, i. 718. See CONTRACTILITY. Excrement. See Faces. Kxcrementitious and recrementitious secretions, ii. 149, 150. Excrescences of the anus, i. 184. from the skin of the foetus in utero, ii. 333. EXCRETION, i. 144. 147. I. necessity of excretion, ii. 148. II. products to be held excretions, ii. 149. 1 . excretions from the bowels, ii. 149. 1 EXCRETION — continued. 2. excretions from the kidneys (urine), ii. 149. 3. lungs, ii. 149. 4. skin, ii. 149. excrementitious and recrementitious secretions, ii. 150. III. effects of the suppression of the secretions on the animal economy, ii. 150. IV. manner in which" secretions are effected, ii. 150. V. matters of excretion are separated from the blood rather than formed at the parts where they appear, ii. 151. VI. original source of the matters thrown out by secre- tion, ii. 152. Excretory duct, ii. 486. structure of, ii. 487. organs of animals, iv. 443. ducts of gall-bladder and liver, iii. 164. glands of Entozoa, ii. 136. passages, iii. 502. Exercise, effects of, on the quantity of carbonic acid gas in the expired air, iv. 348. Exfoliation of bones, i. 453. Exhalations of vegetables, i. 132. Exoccetus, or flying-fish, mode of flight of the, iii. 429. Exomphalos, i. 508. Exosmosis, ii. 98. Exostosis,\. 449. 458. description of, i. 458. causes of the disease, i. 459. venereal poison, i. 459. consequences, i. 459. distinguishable from nodes, i. 460. morbid anatomy of, i. 460. symptoms of, i. 459. Exostosis of bones of the face, ii. 220. of the cranium, i. 745. Expiration and inspiration, comparative force of muscular movements of, iv. 336. See RESPIRATION. Extension, a motion of joints, i. 256. Extensor carpi radialis brevior muscle, ii. 369. longior muscle, i. 217 ; ii. 160. 366. carpi ulnaris muscle, ii. 369. coccygis muscle, s. 137- communis digitorum muscle, ii. 369 ; iii. 131. brevis digitorum pedis muscle, ii. 357. digitorum longus tendon, i. 149 ; ii. 352 ; iii. 137. relations and action, iii. 137. ossis metacarpi pollicis muscle, ii. 369. primi internodii muscle, ii. 370. poUicis tendon, i. 149. proprius pollicis pedis muscle, ii. 352 ; iii. 131, 137. action and relations, iii. 137- proprius primi digiti jnanus, or indicator muscle, ii. 370. secundi internodii pollicis, ii. 370. EXTREMITY (in human anatomy), ii. 154. superior extremity, ii. 154. clavicle, ii. 154. development, ii. 156. structure, ii. 156. scapula, ii. 159. development, ii. 159. structure, ii. 159. humerus, ii. 159. development, ii. 161, 1G2- structure, ii. 161. fore-arm, ii. 162. ulna, ii. 162. development, ii. 164. structure, ii. 163. radius, 163. development, ii. 164. structure, ii. 164. hand, ii. 165. See HAND. inferior extremity, ii. 165. femur, ii. 165. development, ii. 167. structure, 167. patella, ii. 168. development, ii. 168. structure, ii. 168. leg.ii. 168. tibia, ii. 168. development, ii. 171. structure, ii. 170. fibula, ii. 170. development, ii. 171. structure, ii. 171. abnormal conditions of the bones of the extremities, ii. 171. See also OSSEOUS SYSTEM (comp. anat.) ; SKELETON. the lower extremities of man compared with those of the lower animals, iv. 1296. great or splenic extremity of the stomach, s. 308. or cauda, of the medulla oblongata, iii. 679. thoracic, i. 216. refrigerating effects of cold water applied toan, ii. 660. anterior extremity of birds, i. 284. See AVES. Extrophy of the urinary bladder, i. 391. Extroversion of the urinary bladder, i. 391. 503. See BLADDER, abnormal anatomy. GENERAL INDEX. 779 EYE. ii. 171. aqueous humour, ii. 201. Bibliog. and Refer., ii. 206. cornea, ii. 175. chemical composition, ii. 177. development, ii. 178. form and size, ii. 176.' wounds and diseases, ii. 177. opaca, ii. 175. 177. transparens, ii. 175, 176. choroid coat or membrane, ii. 178. corpus ciliare. ciliary processes, ii. 180. orbiculus s. circiilus'ciliaris, — ciliary circle, ii. 180. pigmentum nigrum, ii. 180, 181. MM, ii. 181. tapetum, ii. 179. gland or muscle, ii. 205. crystalline Ions. ii. 194. aqua Morgagni. ii. 200. capsule, ii. 199. chemical composition, ii. 197. development, ii. 195. form, shape, and size, ii. 194, 195. definition, ii. 171. general view of the mechanism of the eye, ii. 171. component parts, ii. 172. form and size, ii. 173. iris, ii. 182. blood-vessels and nerves, ii. 183. development, ii. 184. membrana pnpillaris, ii. 184. demonstration of, ii. 184. structure of, ii. 182. 183. pecten s. marsupiutn nigrum, ii. 203. retina, ii. 185. bloodvessels, ii. 186. foramen centrale, or foramen of Sommerring, ii. 188. layers, or membranes, ii. 186. lamina cribrosa, ii. 185. neurilema, ii. 185. porus options, ii. 186. yellow colour round the foramen, ii. 189. sclerotic coat or membrane, ii. 174 ; iii. 88. inner and outer surfaces, ii. 174. thickness of the coat, ii. 174. tunica albuginea, or white of the eye, ii. 174. vitreous humour, ii. 191. canal of Petit, ii. 192. corona ciliaris, ii. 193. See also VISION. in infancy, i. 73. in old age, i. 80. retina, function of the, iv. 1439. Entozoa in the interior chamber of the, ii. 119. and in the eyes of various animals, ii. 121. consensual movements of the two eyes, ijj. 791. adaptation of the eye to distances, fii. 792. eye of the Albino, i. 84. effect of section of the portio dura of the seventh nerve on the eye, iv. 553. comparison between the ear and the eye, ii. 562. abnormal vision arising from faulty configuration of the eye. See VISION. gerontotoxon, or arcua senilis, i. 80. presbyopia, i. 80. Eyebrows, in mm, iii. 80. muscles of the, iii. 80. See also FACE. in comparative anatomy, iii. 95. Eye-glasses, improper use of, and its consequences, iv. 1463. Eyelashes, in man, iii. 80. in comparative anatomy, iii. 95. Eyelids (in human anatomy), iii. 78. See LACHRYMAL ORGANS. atheromatous and meliceric deposits of the, iv. 97. (in comparative anatomy), iii. 94. See LACHRYMAL ORGANS. FACE (in anatomy generally), ii. 207. See also OSSEOI'S SYSTEM. FACE (in human anatomy), ii. 207. face of man a distinctive characteristic of his superiority, iv. 1296. face of man compared with that of the lower animals, iv. 1296. Bibliog. and Refer. See ANATOMY (Introduction). definition, ii. 207. general view of the face, ii.215. articulations, ii. 219. See CRANIUM ; TEMPORO- MAXILLARY ARTICULATION. cavities, ii. 217. See NOSE; ORBIT. development, ii. 218. dimensions, ii. 215. mechanism of the face, ii. 217. 1. bones of the face, ii. 207. jaw-bone, lower, ii. 213. connexions and uses, ii. 215. development, ii. 215. structure, ii. 215. FAC E— continued. lachrymal bones, ii. 212. connexions, ii. 212. structure and development, ii. 212. malar bones, ii. 211. connexions, ii. 211. structure and development, ii. 212. maxillary bones, superior, ii. 207. connexions, ii. 209. development, ii. 209. sinus, ii. 209. os intermaxillare, ii. 210 structure of maxillary, ii. 209. nasal bones, ii. 212. connexions, ii. 212. structure and development, ii. 212. palate bones, ii. 210. connexions, ii. 211. structure and development, ii. 211. turbinated, or spongy bones, inferior, ii. 213. connexions, ii. 213. structure and development, ii. 213. vomer, or ploughshare, ii. 213. connexions, ii. 213. structure and development, ii. 213. abnormal condition of the bones, ii. 219. abscesses, ii. 220. acephalia, ii. 220. caries, ii. 220. cy-t-like tumours, ii. 220. defect or arrest of development, ii. 219. excessive development, ii. 220. exostosis, ii. 220. fungous growths, ii. 220. hypertrophy and atrophy, ii. 220. hydatids (acephalo-cystus), ii. 220. inflammation, ii. 220. medullary sarcoma, ii. 220. necrosis, ii. 220. osteo-sarcoma, ii. 220. bones of the face in infancy, i. 69. 2. muscles of the face, ii. 220. corrugator supercilii, ii. 222. See CRANIUM, muscles of the. levator palpebrae superioris, ii. 222. relations and action, ii. 222. orbicularis palpebrarum, ii. 2*21. relations and action, ii. 221. muscles of ihe nasal region, ii. 222. depressor alae nasi (myrtiformis), ii. 223. relations, ii. 223. dilator alae nasi, ii. 223. levator labii superioris alaeque nasi, ii. 222. pyramidalis nasi, ii. 222. triangularis nasi, ii. 223. relations and action, ii. 223. muscles of the labial region, ii. 223. buccinator, ii. 225. relations and action, ii. 226. depressor anguli oris (triangularis oris), ii 225. relations and action, ii. 225. depressor labii inferioris (quadratus meuti), ii. 225. relations and action, ii. 225. levator anguli oris, ii. 224. relations and action, ii. 224. levator labii superioris, ii. 224. relations and action, ii. 224. levator menti, ii. 225. action, ii. 225. naso-labialis, ii. 224. orbicularis, ii. 223. relations and actions, ii. 223, 224. platysma myoides, ii. 226. zygomaticus major, ii. 224. relations and action, ii. 224. zygomaticus minor, ii. 224. relations and action, ii. 224. general review of the muscles of the face, ii. 227. 3. integuments of the face, it. 227. 4. vessels of the face, ii. 227. See CAROTID ARTERY. lymphatic vessels of the, iii. 231. superficial, iii. 231. deep-seated, iii. 231. 5. nerves of the face, ii. 228. See FIFTH PAIR OF NERVES ; SEVENTH PAIR OF NERVES. 6. abnormal condition of soft parts of face, ii. 228. blood-vessels, ii. 228. vascular naevi, ii. 228. cellular tissue, ii. 229. congenital malformations, ii. 229. fissure, iv. 953. double hare-lip, iv. 953. single hare-lip, iv. 953. fissure of the palate without a hare-lip, iv. 953. fissure of the under 1 p, iv. 954. skin, ii. 229. abscesses, ii. 229. erysipelas, ii. 229. hare-lip, ii. 229. SE 2 780 GENERAL INDEX. Facets, articular, of sacrum, s. 118. Facial artery, ii. 227. 556 ; iii. 93. 733. 949. transv rse, ii. 227 ; iii. 903. or external surface of malar bone, ii. 211. or anterior surface of superior maxillary bones, ii. 207. nerves, ii. 289. 540. 554. 555; iii. 707. 949. See SEVENTH PAIR OF NERVES. ophthalmic vein, iii. 94. vein, ii. 227; iv. 1382. 1404. 1406. origin and course, iv. 1404. branches of the facial vein, iv. 1404. posterior, iv. 1405. transverse, ii. 228 ; iii. 903. deep, or alveolar, iv. 1404. Facics Hippocratica, i. 802; ii. 747. lunata of acetabulum, ii. 777. Faeces, the, s. 372. composition of the faeces, iv. 458; s. 372. 374. physical properties, s. 373. odour and colour, s. 373. causes, s. 373. specific gravity, s. 374. quantity evacuated, s. 374. mechanical composition, s. 374. chemical composition, s. 375. fatty matters excreted in the faeces, iv. 97. time during which the contents of the intestinal tube sojourn in its different segments, s. 376. occurrence of fatty stools in connexion with pancreatic disease, s. 112. muscular action in the expulsion of the, iii. 721 L. " Fcecal orifices " of sponges, i. 612. Falciform ligament, i. 13; iii. 160. of the liver, iii. 936. 941. Falco nisus (hawk), nervous system of the, iii. 622. Fallopian tube, or oviduct, s. 597. normal anatomy, s. 597. form ; dimensions, s. 597. situation and connexions, s. 598. separate parts and divisions, s. 599. internal orifice, 599. uterine portion of the tube, s. 600. canal, s. 600. external orifice, s. 600. pavilion or infundibulum, s. 601. fimbriae, s. 602. tubo-ovarian ligament, s. 602. structure of the coats or tunics, s. 603. blood-vessels and nerves, s. 604. functions of the Fallopian tube, s. 605. reception and transmission of ova and spermatic fluid, s. 605. first steps in the process of impregnation, s. 608. the changes which the ovum undergoes in the tube, s. 609. approximation of the fimbriated extremities of the Fallopian tubes to the ovary after fruitful sexual union, ii. 447. development of the Fallopian tube, s. 613. formation of the oviduct out of the duct of Miiller, 613. abnormal anatomy of the Fallopian tube, s. 614. defect and imperfect development, s. 614. peculiarities of construction, s. 615. displacements, s. 616. obliteration of the canal, s. 617. hyperaemia ; inflammation, s. 617. collections of fluid within the tube ; blood ; serum; pus, s. 617. cysts, s. 620. fibrous tumours, s. 620. tubercle ; cancer, s. 620. rupture of the tube walls, s. 6:20. Fallopian tube gestation ; various forms, s. 620. See also GENERATION. Fallopius, aqueduct of. ii. 540 ; iv. 546. development of, Ii. 559. hiatus of, i. 733. ligament of, i. 5, note a. Falsetto voice, or voce di testa, iv. 1483. Faljc cerebelli process, iii. 629. cerebri process, i. 729, 730; iii. 629. partial deficiency of the falx, iii. 715. Fangs, poison, of serpents, iv. 290. Farina, nutritive properties of, ii. 13. FASCIA (in anatomy generally), ii. 229. 264. 1. cellular or superficial fasciae, i. 3*. 13 ; ii. 229. 2 aponeuroses, or aponeurotic fascia?, ii. 231. 264. essential properties and uses of, ii. 264. See also FIBROUS TISSUE. Fascia in particular : — abdominal, s. 138. of ankle, i. 148. buccal, ii. 227. cervical, iii. 568. pree- vertebral, iii. 569. cervico-thoracic septum, iii. 570. clavicular, i. 360; iv. 1407. crural, or fascia lata, s. 138. deep, of the leg, iii. 139. dentata, iii. 675. Fascia — continued. of foot, ii. 352. of the fore-arm, ii. 362. iliaca, i. 11, 12. 14 ; ii. 231. 240. 838 ; s. 138. ischio-coccygeal, i. 179. -rectal, i. 177. of knee, iii. 48. lata, or crural fascia, ii. 239 ; s. 138. iliac portion, ii. 239. superficial portion, ii. 239. lumbar, s. 125. 138. lumborum, i. 8. 10. of neck, ii.230; iii. 536. prse- vertebral of the neck, iii. 569. obturator, i. 177.388. palmar, ii. 525. disease of the, ii. 517. 525. palpebral, ii. 227. parotid, iv. 423. pelvic, ii. SSI ; iii. 922. 933; s. 138. recto-vesical, iii. 922. of penis, iii. 912. perineal, s. 138. deep, s. 138. superficial, s. 138. plantar, ii. 354. propria, ii. 231. 841. of the hernial sac, i. 13. psoo-iliac, ii. 838. of quadratus lumborum muscle, s. 138. semilunar, i. 219. spermatica, i. 5. deep, iv. 986. superficial or external, iv. 986. subcutaneous, ii. 62. superficial, i. 216; ii. 851. of abdomen, ii. 230. See ABDOMEN. of the thigh, ii. 238; iii. 128. internal, ii. 231. of the neck, iii. 566. of perineum, iii. 927. temporal, i. 749. transversalis, i. 8. 11, 12; ii. 231. 240. 841 ; s. 138. transversi perinaei, i. 178. vesical, i. 388. Fasciculi of ciliary nerve, ii. 282. lateral, ii. 269. innominati, or olivary tracts, iii. 678. of medulla oblongata. See Medulla oblongata-co- lumns. muscular of the back, i. 374. inter-spinales i. 374. inter-transversales, i. 374. multifidus spinae, i. 374. muscular of the bladder, i. 380. muscular, which dilate and compress the nostrils, iii. 729. Fasting, movements of the stomach in the state of, s. 311. effects of fasting on the quantity of carbonic acid gas in the expired air, iv. 347. FAT, or hydro -carbon, i. 63 ; ii. 233. absorption of, i. 63 ; ii. 232. blood, adipose matter in the, i. 59. chemical constitution of fat, i. 59; ii. 232. composition, elementary, i. 59. deposition of, mechanism of, i. 60. excessive, i. 62; ii. 718. distribution of, i. 62. diminution, excessive, i. 62. foetus, fat and marrow in the, i. 60, 61. formation of fat, ii. 232. lipoma, i. 63. marrow of bones, fat in the, i. 58. 434. melanosis, i. 64. microscopical and atomical structure of, i. 58. mode of separating the stearin and elain of fat, and the fat from its associated cellular texture, ii. 232. morbid conversion of muscle into fat in the living body, ii. 235. sarcoma, adipose, i. 63 secretion, mode of, i. 59; ii. 232. steatoma, i. 63. varieties of fat, and their characteristics, ii. 232 — 235. adipocere, ii. 235. See AUIPOCERE. beef fat, ii. 233. birds' fat, ii. 234. goats' fat, ii. 233. human fat, ii. 232. insects' fat, ii. 23-1. lard, ii. 232. mutton fat, ii. 233. neats'-fpot oil, ii. 233. phocenine, ii. 234. spermaceti oil, ii. 233. train or whale oil, ii, 233. vegetable fat, i. 56. 68, 59. See also ADIPOSE TISSUE. fit considered as an article of food, s. 386. 390. uses sustained by, in the organism, s. 386. 391. fatty matter in corn, s. 393. method of determining the presence of fatty matters ii organic substances, iii. 796. GENERAL INDEX. 781 FAT — continued. quantitative analysis of fat, iii. 798. adventitious formation of fatty and oily substances, iv. 94. fatty infiltration, iv. 94. a. in the liver, iii. 190 ; iv. 94. b. pancreas, iv. 95 j s. 111. c. mammae, iv. 95. rf. kidney, iv. 95. 262. e. testicle, iv. 96. /. lungs, iv. 96. . arteries and cardiac valves, iv. 96. . muscles, iv. 96. 642. 1. voluntary, iv. 96. 2. involuntary, iv. 96. i. tendons, iv. 96. k. nerves, iv. 9doriferae), iii. 914. meatus urinarius, iii. 914. microscopic anatomy of the glans penis, iii. 914. Glasserian fissure, i. 733. 735 ; ii. 545. Glaucoma, or pearl animalcules, ii. 192; iv. 13. Gleno-humeral, or Flood's, ligament, iv. 575. Glenoid cavity, i. 219. 735; ii. 340 ; iv. 573. of radius, ii. 163. of scapula (sinus articularis), ii. 157. of the tibia, external, ii. 168. internal, ii. 1G8. ligament, ii. 157; iv. 573. carpal anterior, ii. 508. posterior, ii. 608. of metacarpo-phalaugeal joints, ii. 510. Glenophora, a genus of Rotifera, iv. 401, et seq. Gliding motion of joints, i. 2?6. Glisson's capsule, iii. 166. See Capsule of Glisson; LI- VER. Globules of chyle, iii. 221. of the blood, i. 404. See BLOOD. of lymph, iii. 219. mucus, iii. 483. varieties of the mucus globule, iiL 484. distinction of the pus and mucus, iii. 484. Globuline of M. Lecanu, i. 411. as an adventitious product, iv. 94. Globulus Arantii, or corpus sesamoideum, i. 223. Globus major of epididymis, iv. 979. minor, iv. 979. Globus, or sense of suffocation, in hysteria, causes of, iii. 722 L, 722 Q. Glomeridce, a family of Myriapoda, iii. 546, et seq. characters of the family, iii. 546. Glomeris, a genus of Myriapoda, iii. 546, et seq. Glomus of the Wenzels, iii. 635. Glossanthrax, or malignant pustule of the tongue, iv. 1156. Glossitis, erectile, iv. 1153. suppurative, iv. 1153. mercurial, iv. 1154. Glosso-epiglottid folds, iii. Ill ; iv. 1121. ligament, iii. 104. Glosso-pnaryngeal nerve, i. 732 ; ii. 494 ; iii. 707. 882, 949. branches, ii. 496. carotid branches, ii. 496. digastric and stylo-hyoid branch, ii. 496. lingual branches, ii. 497. pharyngeal branches, ii. 496. tonsillitic twigs, ii. 497. origin and cranial course, ii. 494, 495. ganglion jugulare, ii. 495. ramus tympanicus nervi glosso-pharyngei, or nerve of Jacobson, ii. 495. physiology of the glosso- pharyngeal, ii. 497 — 500; iv. 500. Glosso-staphylinus muscle, iii. 952; iv. 1132. artion and relations, iv. 1133. Gl (tic dyspnoea, operation for, iii. 573. Glottis. See LARYNX. diseases of the. See LARYNX. Glottology, iv. 1345. See VARIETIES OF MANKIND. Glow-worms. See LUMINOUSNESS, ANIMAL. Glue, method of obtaining, ii. 404. See GELATIN. GLrr.tAL REGION (in surgical anatomy), ii. SOU. arteries, ii. 501, 502. boundaries, ii. 500. definition, ii. 500. muscles, nerves, and veins, ii. 501, 502. Gltit&al artery, ii. 250. 833. course and distribution, ii. 833. impression, s. 115 muscle, maxiraus, i. 61. 177; ii. 1C6. 501. 833; s. 115. 137. medius, ii. 500—502. 833 ; s. 137. minimus, ii. 501, 502. 833; s. 137. 790 GENERAL INDEX. G lulceal—cont in ued. nerve, superior, iv. 766. branches, iv. 766. inferior, iv. 766. veins, iv. 1412. Gluten, nutritive properties of, ii. 13. Glycerine in the brain, iii. 688. Gnathostoma aculeatum, a parasitic worm, ii. 134. accessory glands of the digestive system of, ii. 136. Gnats (Culicidae), ii. 867 ; iii. 539. societies of, iii. 16. emigration of societies of the larvae of, iii. 16. Goats, anatomical characters of, s. 508, et seq. goats' fat, chemical characters of, ii. 233. milk of the, iii. 362. analysis of the, iii. 362. pelvis of, s. 157. urine of the, iv. 1280. Weberian on -an of the, iv. 1420, 1421. 1428. Goat-sucker,^ night-jar, habits of, iv. 679. Gobidts, a family of Fishes, iii. 957. Goitre, or bronchocele, iii. 575. danger of operations for the extirpation of tumour in, iii. 576. treatment with iodine, iii. 576. goitre hereditary, iii. 471. Goldfinch (Fringilla carduelis), nervous system of the, iii. 622. GompJiosis, form of articulation, i. 255. Gonidia of lichens, s, 227. GonmTW'pectorale, mode of propagation of, ii. 407. pu vinatum, mode of generation of, ii. 407. Gonorrhoea, iv. 1258; s. 707. pathological changes in the urethra from this disease, iv. 1258. chordee, iv. 1258. hernia humoralis, iv. 1258. co-existence of, with chancre, iv. 1258. consequences of this affection, iv. 1258. Goose (Anas anser), pancreas of the, s. 96. Gordius, or hair-worm, muscles of the, iii. 538. formation of the ova and fecundation of, s. [123.] Gorgonia nobilis, iv. 31. umbraculum, iv. 30. verrucosa, iv. 32. ova of, s. [127.] luminousness of, iii. 198. Gorgonocephali, muscles of the, iii. 537. Gout in the larynx, iii. 123. analysis of the sweat of persons suffering from gout, iv. 844. gouty irritation of the urethra, iv. 1257. tophi, or gouty concretions, iv. 90. chemical composition of, iv. 91. Graafian vesicles, or follicles, s. 56. [81.] structure of, s. 550. form, s. 550. tunics, s. 551. tunic of the ovisac, s. 551. ovisac, s. 551. origin and development of the Graafian follicle, s. 554. growth, maturation, and preparation for dehiscence, of the follicle, s. 555. rupture or dehiscence of the follicle, and escape of the ovum, s. 558. decline and obliteration of the follicles, s. 561. without impregnation, s. 561. after impregnation, s. 563. changes in, after sexual union, ii. 449. bursting of the vesicles, ii. 449. discovery of the contents of the, ii. 448. Gracilis muscle, s. 137. nerve to, iv. 764. Grallatores, or wading birds, characters of, i. 269. mode of flight of the, iii. 429. pelvis of the, s. 169. Granular excrescences on the valves of the aorta, i. 191. Granulation of fractured bones, theory of, i. 446. 602, 603. See CICATKIX. development of, i. -c>2. Granulation, semi-transparent grey, iv. 105. Granulations, cerebral. See Glandule Pacchioni. Granules of chy\e, iii. 221. osseous, iii. 848. See OSSEOUS TISSUE. Grasshopper, powers of leaping of the, iii. 474. Gravid uterus. See Uterus. Graviditas interstitialis, s. 621. tubaria, s. 621. tubo-ovaria, s. 621. Gravitation, law of, referred to, iii. 141. Gravity, centre of, defined, iii. 409. specific, of the human body, iii. 412. compared with that of air, water, and mercury, iii. 412. Greenlanders, cranium of, iv. 1326. Gregarina, digestive organs of, s. 295. process of reproduction in, s. 7- Gregarious animals. See Congregation s INSTINCT/ Grey fibres of sympathetic nerve, iii. 598. matter of the nerves, iii. 586. 646. 653. development, iii. 648. Grey matter — continued. 'remarks on the simplicity oT form of the elements of prey nervous matter, iii. 649. pigmf-nt, iii. 647. 649. See NERVOUS CENTRES. Griffithsia, antheridium of, s. 221, 222. Groin, region of the, i. 4, 5. GROIN, REGION OF THE (in surgical anatomy), ii. 503. See ABDOMEN; FFMORAL ARTERY; HERNIA. Groove, infra-orbitar, ii. 208. lachrymal, iii. 90. mylo-hyoid, ii. 214. osseous, for lodgment of lachrymal sac, iii. 90. of promontory of cochlea, ii. 543. of sacrum, s. 118. sub-pubic, or obturator, s. 116. Grooves of palate bones, ii. 211. of ribs, iv. 1031. Ground-beetles, ii. 859. Growth of man, i. 65. Growths, malignant, method of performing the analysis of, iii. 806. in the oesophagus, iii. 761. Gryllotalpa vulgaris, or mole-cricket, ii. 864. mode of flight of the, iii. 421. Gryllus campestris, mode of flight of the, iii. 421. vocal organs and voice of the, iv. 1503. domesticus, or house-cricket, mode of flight of the, iii. 421. powers of leaping of the, iii. 471. Gryporhynchus pusillus, a parasitic worm, ii. 127. Gnanches of the Canary Islands, language of the, iv. 1357. Guber of Sudan, characters of the, iv. 1352. Gubernaculum testis, i. 7 ; iv. 982. Guinea-pig (Cavia), anatomy of the, iv. 372, et seq. mode of locomotion of the, iii. 454. pelvis of the, s. 159. urine of the, iv. 1281. Guinea-worm, i. 517 ; ii. 122. See ENTOZOA ; Filaria Medinensis. Gullet. See CEsopHAGUs. Gums (gingivre), iii. 951. See also Pnlatine Arch. vessels and nerves of the gums, iii. 951. diseases of the gums. iii. 954. Gun-shot wounds of arteries, i. 227. of knee-joint, iii. 49. Gustatory nerve, ii. 292. 498; iii. 721 ; iv. 1141. satellite vein of, iv. 1404. Gut, etymology of the word, s. 294. blind, s. 362. See Ccecum. great, s. 365. See Colon. straight, s. 368. See Rectum. See also STOMACH AND INTESTINE. Qvthrie't muscles, iii. 930 ; iv. 1264. Gymnica, a section of Polygastric animals, iii. 5. Gymnoriontes, a family of Fishes, iii. 957, et seq. Gymnogramma chn sophylla, prothallium of, s. 240. Gymnotus electricus, ii. 81. intestinal tube of the, iii. 982. anatomy of the electrical organs, ii. 91. haunts of the fish, ii. 82. circumstances under which it discharges electricity, ii. 83. Indian methods of capturing the fish, ii. 84. motions of the fish in discharging electricity, ii. 83. physiological and chemical effects of the discharge, ii. 84 — 86. production of sparks and evolution of heat,'ii. 87. results of experiments on the nerves and electrical organs, ii. 87. uses of the electrical function, ii. 97. See ELECTRICITY, ANIMAL. Gyrodactylus auriculatus, a cestoid parasitic worm, ii. 130. H. Habena;, or peduncles, of the pineal gland, iii. 677. Habitations of animals, instincts designed for the purpose of guiding them in the formation of, iii. 9—11. Hachisch, intoxicating effects of, iv. 690. Hcemadynamometer, the, iv. 1060. H&maphcein, iv. 1270. Hcematocele of the spermatic cord, iv. 1003. encysted haematocele of the spermatic cord, iv. 1003. of the testicle, iv. 1002. encysted haematocele of the testicle, iv. 1003. Heematoma, causes of, iv. 125. HJSMATOSINE (or hajmatine), i. 411 ; ii. 503. analyses of, ii. 504. cause of the red colour, i. 422 ; ii. 504. precipitates of, ii. 503. morbid conditions, i. 422. UcEmntometra, s. 697. H&maiuria, i. 401. Hcemoptoe caused by a course of mercury, i. 232. H&morrhage, alarming, in imperfect coagulation of the blood, i. 418. arterial,]. 228. natural suppression of, i. 229. permanent suppression of, i. 229. GENERAL INDEX. 791 Hemorrhage- continued. into the adipose tissue, i. 62. from the bladder, i. 401. causes of the disease, i. 401. cerebral, iii. 720 D. apoplexy, cerebral, iii. 720 D. capillary, iii. 720 D. of the digestive canal, s. 408. from the mucous membranes, causes of, i. 4IG. passive, ca'ise of, i. 422. secondary, iii. 133. syncope from, i. 796. Htemorrhaafc purpura of the foetus in utero, ii. 33'i. HiFniiirrkagic reaction, i. 797. H&morrhoidal (anal) nerve, inferior, iv. 766. artery, middle, i. 386 ; ii. 830 ; s. 350. superior, i. 196; s. 380. of the rectum, i. 181. plexus of nerves, s. 430. of veins, iii. 933; iv. 1412; 8.381. veins, inferior, iii. 933; iv. 1412. superior, iv. 1412. 1414. Hemorrhoids, iv. 1399. external and internal, of the rectum, i. 185. Hairs, structure of. s. 478. 496. composition of the shaft of a hair, s. 496. cuticle, s. 496. cort cal tissue, s. 4%. medullary substance, s. 497. hair-sac, s. 497. outer root-sheath, s. 497. fenestrated inner root- sheath, s. 497. imperforate root-sheath, s. 497. colour, texture, and mode of growth of the hair, considered as a characteristic of the various races of mankind, iv. 1337. See TEGU MENTARY ORGANS. adventitious production of, iv. 142. defaecation and pilimiction of hair, iv. 142. concretions of, analysis of, iii. 806. on the arm, i. 216. of the face, ii. 227. of the head, i. 747; iv. 1337. part which first begins to grow grey, i. 749. of the nose, iii. 7*9. sebaceous glands of the nose, iii. 729. Hair-balls in the intestines of the lower animals, iv. 81. Hake, brain of, iii. 764. Halibut, brain of, iii. 764. Halichcerus gryphus, or grey seal, dentition of the, iv. 915. Halicondria, a group of Porifera. structure of, iv. 66. Halicondria, a genus of Porifera, iv. 68. propulsion of water through its oscula, iv. mode of reproduction of, iv. 70. Halidrys siliquosa, antheridia of the, s. 215. Hnlina papillaris, i. 103. Halispongia, a family of Porifera, iv. 65. characters of the family, iv. 65. Hall82. bicuspid or mitral valve, ii. 583. >< nfiliiuar valves, 11 sinuses of Valsalva, ii. 584. circumference of the aortic and pulmonary orifices, ii. measurements, ii. 587. relative capacities of the several cavities, ii. 585. measurements, ii. 586. relative dimensions of the auriculo-ventricular orifices, ii. '-7. jx-ptum of the ventricles, ii. 584. size ;md weight of the heart, ii. 587. G83, note. thickness of walls of cavities of, ii. 585. measurements, ii. 585. sti ucture of the heart, ii. 587. bl < d-vessels of the heart, ii. 596; iv. 1414. great coronary vein, ii. 596. sinus of the coronary vein, ii. 597. smaller anterior coronary vein, ii. 5<»7. smaller posterior coronary vein, ii. 597. venae minims, or veins or Thebesius, ii. 597. inner membrane of the heart, ii. 594. lymphatics of the heart, ii. 597 ; iii. 229, 230. n'mscular tissue, ii. 590. of auricles, ii. 593. of ventricles, ii. f>90. nerves of the heart, ii. 595. cardiac, inferior, left, and middle, ii. 595. cardiac plexus, ii. 595. motor influence of the sympathetic in reference to the heart, s. 4GO. pericardium, ii. 597. uses, ii. 698. vessels within the pericardium, relative posi- tion of the, ii. 598. tendinous texture of the heart, ii. 687. arterial tendinous ring*, ii. 587. attachment of the middle coat of the arteries to the arterial tendinous rings, ii. 589. auriculo-ventricular tendinous rings, ii. 587. tendinous structure in the arterial valves, ii.589. tendinous structure in the auriculo-ventricular valves, ii. 539. peculiarities of the foetal heart, ii. 599. Eustachian v;ilve, ii. 599. valve of the foramen ovale, ii, 599. the heart in infancy, i. 65. a-symmetry of the'heart, iv. 846 HEART," PHYSIOLOGY OK THE, ii. 600. action of the valves, mode of, ii. 600. iMu28. construction of the auricles, ii. 628. septum auriculorum, ii. 629. Sup p. HKART, ABNORMAL CONDITIONS ov IHE, ii. 630. 1. Congenital abnormal conditions ii. 334. 630 ; iv. 949. aberrations of position— ect< pia cordis, ii. 630. absence of the pericardium, ii. 633. anomalous connexions of the vessels, ii. €35. defect of development, malformations by, ii. 631. displacement or ectoi-ia of the heart as a conse- quence of disease, ii. 635. excess of development, malformations by, ii. 634. valves, malformations of the, ii. 633. II Morbid alterations in the muscular tubstanceof the heart, ii. 636. aneurism of the heart, ii. 640. atrophy of the heart, ii. 642. cartilaginous and osseous transformations, ii. G37. dilatation of the cavities of die heart, — passive aneurism, ii. 640. dilatation of the orifices of the heart, ii. 640. fatty destruction of the heart's substance, iv. 96. hypertrophy, ii. 638. simple, i. e. without change in the capacity of the cavities, ii. 638. concentric,! e. with diminution of capacity, ii. 638. excentric, i.e. with dilatation or increased capacity, — active aneurism, ii. 639. cor bovinum, ii. 639. induration, ii. 637 ; iv 707. inflammation— carditis proper, ii. 636. melanosis, ii. 638. medullary fungus, encephaloid tumours, ii. 637. morbid deposit of fat on the heart, — fatty degenera- tion, ii. 642. rupture of the heart, ii. 643 scirrhus, ii. 637. suppuration, ii. 636. tubercles, ii. 637. ulceration, ii. 637. III. Morbid states of the membranes of the heart, ii. 643. chronic valvular diseases, ii. 646. atrophy of the valves, ii. 647. chronic endocarditis, ii. 646. dilatation of the valves, ii. 647- osseous deposits, ii. 647. ossification, ii. 647. thickening of the edges of the valves, ii. 646. cysts, ii. 615. endocarditis, — morbid states of the endocardium, ii. 645. entozoa in the heart, ii. 647. hydrops pericardti or hydropericardium, ii. 645. pericarditis, — morbid states of the pericardium, ii. 643. pneurnopericardium, ii. 645. softening of the lining membrane, iv. 708. tubercular formations, ii. 645. white spot on the heart, ii. 644. states of the blood in the heart after death, ii. 648. Heartburn, causes of, iii. 759, 760. Hearts, lymphatic, of reptiles, iv. 302. HEAT, ANIMAL, ii. 648. an essential condition for the performance of vital actions, iii. 147. temperature of the human body, ii. 649. of Mammalia, ii. 649. of Birds, ii. 649. of Reptiles, ii. 649. of Fishes, ii. 649. of Insects, ii. 6-iO. of Crustacea, ii. 650. of Mollusca, ii. 650. general conditions of organisation in relation with the production of a greater or less degree of heat, iii. 650. temperature of different parts of the body, ii. 654 relation between the temperature ol internal parts, ii. 654. relations in point of temperature between external parts, ii. 655. difference of temperature according to depth, ii. 656. influence of external temperature generally, ii. 658. variations in the temperature of animal bodies in a state of health independently of external tempera- ture, ii. 658. influence of the natural temperature of the air on that of the body, ii. 658. influence of temperature on the vitality of cold- blooded animals, ii. 673. influence of temperature on the vitality of warm- blooded animals, and of man, in the states of health and disease, ii. 674. effects of various other causes of modification in ex- ternal agents, ii. 680. means for effecting a reduction of animal heat, ii. 680—682. affusion of cold water, ii. 681. air, natural temperature of, ii. 680. in a state of motion or at rest, ii. 681. sudden transitions of, ii. 6»l. bloodletting, ii. 681. diaphoretics and purgatives, ii. 682. diet and regimen, ii. 682. 3 F 794- GENERAL INDEX. HEAT, ANIMAL — continued. means for effecting an increase of animal heat, ii. 682, quinia, ii. 682. confirmation of general results, ii 682. of f'e physical cause of animal heat, ii. 683. Lavoisier's theory of combustion of the carbon and hydrogen of the blood by the oxygen of the air, ii. 684. influence of the spinal cord on the function of calorifi- cation, iii. 72 IS. impaired evolution of heat during the sleep of hiber- nating animals, ii.767. influence of different media upon temperature, ii. 659. effects of external temperature upon an isolated part of the body, ii. 660. effects of partial t-o >ling, ii. 660. effects of partial heating, ii. 660. . effects of an excessively high or excessively low external temperature upon the temperature of the body, ii. 660. influence of evaporation, ii. 661. relations of the bulk of the body to animal heat, ii. 662. relations of age to animal heat, ii. 662. periods of youth at which the bodily temperature differs from that of the adult age, ii. 603. differences of constitution in relation to the production of heat among animals, ii. 667. influence of the seasons on the production of animal heat, ii. 668. differences according to the nature of the climate, ii. 670. influence of sleep on the production of heat, ii. 670. phenomena presented by hibernating animals with regard to the production of heat, ii. 671. of the system upon which the external temperature acts primarily and principally, ii. 673. difference between the heat of very young animals and of that of hibernating animals, ii. 761. 768. loss of heat sustained by animals which are born blind when removed from the contact of their parents, ii. 771. loss of heat a sign of approaching death, i. 801. development of heat in insects, ii. 988. See IN- SECTA. animal and vegetable heat compared, i. 136. mode in which heat is engendered, i. 136. periodical heat in animals, ii. 441. See GENERATION. Hedgehog family (Erinaceadae), ii. 994. muscular and spiny covering of the hedgehog, ii. 999. uses of, ii. 1004, 1005. structure of the spines of the, s. 498. pelvis of the, s. 104. hibernation of the, ii. 764. See HIBERNATION. Heel-bone, or os calcis. ii. 339. Hfight of the human body at different ages, i. 74. Helamys (Cape jerboa, or jumping hare), anatomy of the, iv. 372. et seq. Helix, ii.550, 551. helicis major muscle, ii. 552. minor muscle, ii. 552. Hdix albolabris, biliary organs of, iv. 448. pomatia, generative process of, ii. 3!<7, 398. spermatozoa in the, ii. 113 ; iv. 486. H:locera, a tribe of Coleoptera, ii. 860. characters of the tribe, ii. 860. Hemadynamo meter, of Poiseuille, i. 662. Hemerobidce, or lace-winged flies, ii. 865. Hemicephalia, iv. 954. See Acrania. Hemielliptical fovea, ii. 530. Hemiplegia, Hi- 37—40. effects of galvanism in cases of, iii 38. 41 . Hemiptera, an order of Insecta, ii. 868. characters of the order, ii. K68. nervous system of the, iii. 610. Hemispheres of the brain, iii. 678. insensibility of the hemispheres to pain from me- chanical division or irritation, iii. 723 C. Hemispherical fovea, ii. 530. Hepatic artery, i. 194, 195 ; iii. 171 ; s. 326. origin and course, iii. 171. distribution, iii. 171. vaginal arteries, iii. 171. interlobular arteries, iii. 171. lobular arteries, iii. 171. Hepatic duct, iii. 164. 169. vaginal ducts and vaginal | lexus, iii. 109. interlobular ducts, iii. 169. lobular ducts and lobular plexus, iii. 169. termination of the biliary ducts, iii. 170. vascularity of the biliary ducts, iii. 170. mucous membrane at.d follicles of the biliary ducts, iii. 171. See also LIVER. Hepatic plexus of nerves, iii. 174 ; iv. 1414 ; s. 429. trunks, iii. 173. veins, iii. 172; iv. 1414. interlobular veins, iii. 173. sub-lobular veins, iii. 173. hepatic trunks, iii. 173. venous canals, iii. 173. r, vegetative system among the lower, a. 232. first period — from the germination of the spore, s. 233. development of the antheridia, s, 233. of the archegonia, s. 233. second period — fructification of the archegonia, s. 234. changes preparatory to the development of the spores, s. -234. development of the spore.*, s. 234. Hepatico-duodenal ligaments, s. 341. Hepatitis, lobular, iii. 188. membranous, acute, iii. 183. complication with congestion of the substance of the liver, iii. 183. characters of the urine in, iv. 1291. Hereditary qualities, mental and physica:, phenomena ol the transmission of, from parent to offspiing, ii. 471. HERMAPHRODITISM. or Hermaphrodism, ii. 084. classification of hermaphroditic malformations, ii. 685. I. Spurious hermuphroditism, ii. 685. A. in the female, ii. 685. 1. abnormal development or magnitude of the clitoris, ii. 686. in some of the lower animals, ii. 689. 2. prolapsus uteri, ii. 090. B. in the male, ii. 690. 1. extroversion of the urinary bladder, ii. 691. 2. adhesion of the inferior surface of the penis to the scrotum by a band of integuments, iii. 691. See BLADDER ; TERATOLOGY. 3. fissure of the inferior part of the urethra, perin a;um, &c., ii. 691 in some of the lower animals, ii. 695. II. True hermaphroditism, ii. 695. A. lateral hermaphroditism, ii. 6C6. 1. ovary on the left side and testeson the right, ii. 698, 2. testicle on the left and ovary on the right, ii. 700. B. transverse hermaphroditism, ii. 701. 1. transverse hermaphroditism with the ex- ternal sexual organs of the female type, ii.701. 2. transverse hermaphroditism with the ex- ternal sexual organs of the male type, ii. 704. C. double, or vertical, hermaphroditism, ii. 706. 1. male vesiculae seminales, &c., supcraddud to organs of the female sexual type, ii. 707. 2. imperfect female uterus, £c., superadded to a sexual organisation essentially male, ii. 707. 3. Co-existence of female ovaries and male testicles, ii. 711. two testicles and one ovary, ii. 712. two testicles and two ovaries, ii. 712. III. Hermaphroditism as manifested in the general conformation of the body, and in the secondary sexual characters, ii. 714. General summary with regard to the nature of herma- phroditic malformations, ii. 722. 1. varieties of spurious hermaphroditism, ii. 722. 2. nature of true hermaphroditic malformations, ii. 723. anatomical degree of sexual duplicity in hermaphro- ditism, ii. 728. 1. fallacies in judging of the addition of male seminal ducts to a female type of sexual or- gans, ii. 729. 2. fallacies in the supposed co-existence of a female'uterus with testicles and other organ of a male sexual type, ii. 730. 3. fallacies in the supposed co-existence of tes- ticles and ovaries, ii. 731. physiological degree of sexual perfection in herma- phrodites, i. 145; ii. 434. 732. causes of hermaphroditic malformations, ii. 733. hermaphroditism in double monsters, ii. 736. See also TERATOLOGY. Hermella, ovum of, s. [117,] [118.] Hermit-crab, nervous system of the, iii. 613. HERNIA (morbid anatomy), ii 738; s. 405. circumstances under which protrusions of the abdo- minal viscera take place, varieties, &c., ii. 738. enterocele, epiplocele,and entero-epip'ocele, ii. 738. arrangement of hernia?, ii. 741. irreducible hernia, ii.7-11. reducible, ii. 741, 742. strangulated, ii. 741. 743. causes which seem to produce the strangu- lation, ii. 743. effect of strangulation on the structures within the sac, ii. 74;~>. effect of strangulation on the viscera within the cavity of the abdomen, ii. 745. symptoms and progress, ii. 74o. congenital hernia, ii. 740. crural or femoral hernia, ii. 7-'i6. affections which may be confounded with it, ii. 760. symptoms and progress of the disease, ii. 7ft9. definition, ii. 738. hernial sac, ii. 738. GENERAL INDEX. HERMA — continued. inguinal hernia, oblique, ii. 7"0. affections which may possibly be confounded with it, ii. 753. See also ABDOMEN. inguinal hernia by direct descent, ii. 755. causes, ii. 755. how distinguishable f:ora oblique hernia, ii. 756. umbilical hernia, ii. 761. congenital, ii. 761. of more advanced periods of life, ii. 762, 7(3 symptoms, ii. 7»;4. J/t'/nia in particular: — cerebri, or encephalocele. iii. 719; iv. 141. 954. 956. of the foetus in utero. ii. 3^0. diaphragmatic, of foetus in utero, ii. 319. fascia propria of the hernial sac, i. 13. fascia spermatica in old herniae, i. 5. fatty, iv. 129. of foetus in utero, ii. 319. 320. humoralis, iv. 1006. infantilis, iv. 1002. inguinal, congenital, i. 508; s. 404. inguinal herniae, external and internal, i. 13. operations for, i. 15. inguinal, of foetus in utero. ii. 319. intercolumnal bands in old herniae, i. 5. of ovary, s. 574. perinea'!, seat of, iii. 932. testis, iv. 1007. of tunica vaginalis, encysted, iv. 1002. umbilical, congenital, i. 508 ; iv. 950. congenital, acquired, iv. 950. of foetus in utero. ii. 319. of the u> inary bladder, i. 395. at the crural ring, i. 396. at the perineum, i. 396, through the vagina, i. 396. of the uterus, s. 634. ventral, congenital, iv. 950. Hernial tumours of the glutaeal region, ii. 502. Ili'rophilus, press of, iii. 631. Hen ing, an inhabitant of the arctic seas, iii. 13. mode of migrating in shoals, iii. 13. eyes of, iii. 1' 02. pyloric caeca of the, s. 94. tongue oi the. iv. 1146. IL'teradelphi, iv. 968. Heterogangliata, a di* ision of Mollusca, iii. 364. muscular system in the, iii. 540. H.-teromera, a section of the order Coleoptera, ii. 863. characters of the section, ii. 863. Hexuprotodon, an extinct genus of Pachydermata, which Hiatus ethmoidalis i. 730. Fallopii, i. 733 ; iv. 545. palatinus, i. 727. Rivinianus, ii. 560. HIBERNATION, ii. 764 ; iii. 31. 157. definition, ii. 765. effects of hibernation, order of consideration of the, ii. 766. enumeration of hibernating animals, ii. 776. I. Of sleep, ii, 776. II. Of the sleep of hibernating animals, ii. 766. difference between the heat of very young and of that of hibernating animals, ii. 768. 771. phenomena presented in the state of the respira- tion and with regard to the evolution of heat of hibernating animals, ii. 671. 767. See also HEAT, ANIMAL III. Of perfect hibernation, ii. 768. causes, i. *63; ii. 768. condition of the several functions in hibernation, ii. 768. circulation, ii. 771. defaecation, ii. 768. 77'2. irritability, ii. 772. 775, 776. muscular fibre, motility of, ii. 773. nervous system, ii. 772. respiration, ii. 769. comparative temperature of hibernating animals with that of the atmosphere, ii. 770. sanguification, ii. 768. nourishment of hibernating animals by absorp- tion of their own fat, ii 153. methods adopted by hibernating animals for secu- riug themselves from disturbance and excite- ment, ii. 774 ; iii 12. IV. Of revivescence, ii. 774. V. Of torpor from cold, ii. 77".. difference between torpor and hibernation; ii. 775. See also IRRITABILITY. difference between simple sleep and hibernation, iv. 678. Hibernating ova. s. [117.] [127], [128]. See Ovr.M. of Rotifera, s. [119]. Hibernation of plants, iii. 157. Hilum of the kidney, iv. 234. Hiltts lienalis, IT. 771. Hindoo, portrait of a female, of Pondicherry, iv. 1350. Hindoos, variety in the complexion of the different races of, iv. 1337. HIP- JOINT, anatomy of the (in human anatomy), ii. 776. arteries, ii. 779. bones, ii. 776. acetabulum, ii, 776. head of the femur, ii. 777. cartilage, ii. 777. fibro-cartilage, ii. 777. ligaments, ii. 777. round ligaments, i. 251 ; ii. 778. capsular ligament, ii. 77*. motions of which the hip-joint is susceptible, ii. 779. nerves, ii. 779. synovial membrane, ii. 779. HIP-JOINT, abnormal conditions of the, ii. 780. I. Congenital malformations, ii. 780. original luxation, ii. 780. anatomical characters of the affection, ii. 782. history of a case of congenital malformation of the left hip-joint, with the anatomical examination of the articulation, ii. 784. history of a second case, ii. 786. II. Disease, ii. 787. inflammation of the syuovial membrane and other structures, ii. 787. arthritis coxae acute, ii. 790. anatomical characters, ii. 792. cases, ii. 790. 791. arthritic coxae, chronic strumous, ii. 793. anatomical characters, ii. 795 cases, ii. 795. 7V6. arthritic coxae, chronic rheumatic— morbus coxae senilis. — chronic r eumati»m, ii. 798. anatomical characters, ii. 801. causes, ii. 798. history of the disease, ii. 798. similar disease affecting other articulations (see ELBOW; HAND ; KNEE; SHOULDER). symptoms, ii. 799. history of two cases, ii. 799. 800. bones, — strumous osteitis, morbus coxae, scro- fulous affection of the hip-joint, ii. 789. cartilages, inflammation and destruction of the, ii.788. " diffuse " inflammation, case of, ii. 788. synovitis coxae with periostitis, ii. 788. symptoms of the early stages oi diseases of the hip- joint, iii. 721 H, 722 H. influence of hip-joint disease upon the pelvis, s. 208. III. Accident, ii. 802. i. fractures, ii. 802. 1. fracture of the acetabulum, it 802. A. fractuie of its fundus, ii. 802. po>t mortem examination of a case, ii. 803. B. fracture of its brim, ii. 80'*. history of a case, ii. 803. 2. fracture of the superior extremity of the femur, ii. 804. A. intra-capsular fracture of the neck of the femur, ii. 804. B. extra-capsular fracture of the neck and fracture of the superior portion of the shaft of the femur, ii. 805. C. fracture of the neck of the femur com- plicatrd with fracture through the trochanter major, ii. 805, 806. D. fracture of the neck of the thigh bone, with impaction of the superior or cotyloid fragment into the cancel- lated tissue of the upper extremity of the shaft of the femur, ii. 806. anatomical characters of fractures of the neck of the thigh-bone, ii. 807. does bony consolidation of the intra-cap- sular fracture of the cervix femoris ever occur ? ii. 810. cases, 811— 814. ii. luxations, ii.815. a. dislocation of the head of the femur upwards and backwards on the dorsum of the ilium, ii. 815. anatomical characters, ii. 816. muscles, ligaments, and bones, ii. 817. 6. dislocation backwards or towards the ischiatic notch, ii.8I8. anatomical characters, ii. 820. c. dislocation upwards and inwards on the puber, ii. 820. anatomical characters, ii. 821. d. dislocation downwards and inwards into the foramen ovale, ii. 122. anatomical characters, ii. 823. e. cases of unusual dislocations ot the head of the femur, ii. x->4. upwards and outwards, ii. 824. downwards and backwards, ii. 824. Hippobosca equina, or forest-fly, ii. Hippocampus, iii. 986. Hippocampus major (or cornu Ammonis), iii. 675. 698. minor (or ergot), iii. 675. 698. 3r 2 796 GENERAL INDEX. Hippomones, iv. 7il. Hfppopotamtts, anatomy of the, iii. 8GO, ct scq. See PACHY- DBBMATA. stomach of the, s. 303. pelvis of the, s. 156. Hippuric, or urobenzoic, acid, iii. 800. analysis of, iii. 800 ; iv. 1270. in diseased urine, iv. 1283. presence of, in the blood, iv. 460. Hippnris vulgaris, development of, s. 240. Hircic acid, ii. 233 ; iii. 362. Hircin. ii. 233. Hirudines, (or leeches), organs and mode of progression of the, iii. 441. ovum of, s. [117.] Hirudinidte, eyes of the. i. 167. respiration of the, i. 171. Hoarseness and loss of voice, causes of, iii. 123. Hog, parasites in the muscles of the, ii. 120. pelvis of the, s, 156. teeth of the, iv. 905. Hollow of the sacrum, s. 127. Holophrya, or woolly animalcule, iv. 13. Holothuria, i. 109 ; ii. 31. Holothuria tubulosa, ova of, s. [125]. Miiller's discovery of the micropyle aperture, s. [125]. nervous filaments of (?), iii. 602. muscles of the, iii. 537. generative system of, ii. 410. alimentary canal of, s. 297. See ECHINOUERMATA. Homaloptera, an order of Insecta, ii. 867. characters of the order, ii. 867. Hotnogangliata, iii. 537. muscular system of the, iii. 538. Homogangliate nervous system of the Articulata. See ARTICULATA. Homoptera, an order of Insecta, ii. 868. characters of the order, ii. 868. Honey, method used by collectors of honey to discover bees' nests, iii. 4?3. Hood, or head-cowl, of Pteropoda, iv. 174. Hoofs, structure of, iv. 437 ; s. 477. of horses. See SOUPEDA. of Ruminants, s. 531. object of the cloven foot, s. 531. Hooked worms, ii. 116. See ENTOZOA. Hordeolum, or stye, iii. 83. Hornets (Vespidse), habits of, ii. 865. their habitations, iii. 11. Horns, sacral, s. 119. Horns of thyroid cartilage, iii. 102. Horny tissue of animals, i. l'_7. " Horns" or adventitious horny matter, iv. 139. Horns of Ruminantia, structure of, s. 47*. 516. Horse, anatomy of the, iv. 715. See SOLIPEOA. stomach and intestines of the, s. 303. Weberian organ of the, iv. 1419. causes of " roaring " of the, iii. 123. computation of the strength of a horse, iii 480. effect of castration on the cerebellum of, iii. 687. and on the general conformation of the body of the. ii.713. flocculent growth of the uvea in the, iii. 95. mark of a stumbling horse, ii. 158. its swimming capabilities, iii. 439. its mode of progression on land, iii. 451. the walk, iii. 452. the trot, iii. 452. the gallop, iii. 453 velocity of the horse, iii. 463 urine of the, iv. 1297. Hottentots, their general resemblance to the Mongolians, iv. 1323. their language, iv. 1356. their physical and mental characters, iv. 1355. peculiarity in the growth of their hair, iv. 1337. their physical and psychical characteristics, iv. 1343. the Bushmen proved to be a degraded caste of Hotten- tots, iv 1343. House-flies, common (Muscida?), ii. 867. Huckle-bone, or whistle-bone. See Coccyx. Humble-bee (Bombus terrestris), ii. 880. thoracic spiracle of, iv. 1505. Humeral artery, i. 465. See BKACHIAL ARTERY. Hunnrus, i. 216 ; ii. 63. 65. 159. condyles of the, i. 217. development, ii. 161. form, ii. 159. anatomical neck of the bone, ii. 159. surgical neck of the bone, ii. 159. tuberosity, greater, ii. 15'J. lesser, ii. 159. structure of the humerus, ii. 161. surfaces, ii 159, 160. fractures of the, i. 218. 362 ; ii. 69. fracture of the superior extremity of the, iv. 601. fracture of the surgical n'-ck of the humerus below the tuberosities and original line of junc- tion of the cpiphysis with the shaft <-f the bone, iv. 005. Humming of insects, iv. 1504. Humming-birds, characters of, i. 267. Humor vitreus auris, ii, 539. Hump of the dromedary, structure of the, s. 531. Hungarian sisters, the, iv. 972. Hunger, perception of, ii. 25. causes of, ii. 25. hypotheses, ii. 25, 26. effect of the lesion of the vagi upon the sensation of, iii. 899. Hytena, dentition of the, iv. 911, 912. brain of the, iii. 696. Hytsna of Van Diemen's land described, iii. 258. Hyalea, a genus of Pteropoda, iv. 178. anatomy of Hyalea, iv. 179. Hyalitic substance, or substance of bone, iii. 487- Set; OS- SEOUS TISSUE. Hyaloid membrane, ii. 192. Hybrid races of mankind, fertility of, iv. 1341. Hybrids, or mules, ii. 445. sterility of, ii. 415. qualities transmitted from the parents to the hybiid offspring, ii. 472. Hydatid polypi of the nose, iii. 740. Hydatids. See ENTOZOA ; Acephalocysts. in the kidney, iv. 263. of the human liver, iii. 196. in the mammae, iii. 252. of the ovary, s. 698. contained in ovarian cysts, s. 584. in pancreas, s. 110. of the upper jaw-bone, ii. 220. Hydatinea, a family of Rotifera, iv. 404, et scq. characters of the family, iv. 404. analysis of the genera of, iv. 404. Hydatina senta, i. 1 10 ; iv. 403. nervous system of the, iii. (.07. Hydatis Finna of Rudolphi, ii. 118. See Cysticercus cellulosse. Hydrias, a genus of Rotifera, iv. 407. Hydra fusca, a genus of Polypifera, iv. 23, 24. ovum of, s. [127.] viridis, or short-armed polyp, iv. 20, 21. digestive organs of, s. '296. biliary apparatus of, iy. 445. substance composing its body, iv. 20. locomotion, iv, 21. mode of progression of the, ii. 432. 533. nervous and muscular tissues not discernible, iii. 533. tentacula of, iv. 21, 22. food of, iv. 21. power of restoring lost parts, iv. 22. mode of reproduction, ii. 408 ; iv. 22 ; s. 17. ova of the hydra, s. 18. [126]. structure of the integuments of the, s. 484. Hydractinea rosea, ova of, s. [127]. Hydraphephaga, a sub-tribe of Coleoptera. ii. SCO. Hydrates of carbon, considered as alimentary substances, s. 386. purposes fulfilled by, in the animal economy, s. 386. Hydrocarbon of biliary secretion, iv. 458. of corn, s. 393. Hydro-carbons, or fats, considered as alimentary sub- stances, s. 386. 390. Hydrocele, i. 6 ; ii. 60. acute, of the tunica vaginalis, iv. 994, 995. analysis of the fluid of hydrocele, iv. 995. multilocular hydrocele. iv. 996. hydro -sarcocele, iv. 996. congenital hydrocele, iv. 996. encysted hydrocele, iv. 997. diffused hydrocele of the spermatic cord, iv. 999. complications of hydrocele, iv. 1001. Hydrocephalus, i. 744. death by, i. 264. of feet s in utero, ii. 320. congenitus, iv. 958. internus, iv. 958. effects of, iv. 960. externus, iv. 9fiO. intemus, causes of, iii. 721. co-existence of hypertrophy of the brain with, iii. 720 disappearance of the convolutions of the brain in, iii. Hydrochloric acid, action of, on protein, iv. 164. on fibrin, iv. 166. m- thod of determining the presence of, in organic sub- stances, ii 802. Hydrocliloro-pepsic acid, s.336, Hydrochcerus, or capybara, anatomy of the, iv. 373, et seq. Hydrocyanic acid, action of, on the vital power of the heart, i. 723. 797. Hydro-encephaloa Ic, iv. 956. Htidrogen, sulphuretted, effect of, on the action of the heart,i. 797. Hydrometra aquatica, iv. 946 ; s. 697. Hydrophili, or water-snakes, mode of progression of the, iii. 434. Hydrophobia, affections of the medulla oblongata in, iii. 722 L. 7'22 Q. produced by contact of morbid saliva with the second skin, iv. 420. Hydr ophthalmia, symptoms of, iv. 1464. GENERAL INDEX. 797 Hydrnps articuli of older writers, iii. 59. pi-ricardii, or hydropericardium, ii. 645. ventiiciiloruin cerebri, iv. 9J3. Hydropiicumuthorax, iv. 145. Hjfdrorachis, iv. 957, 958. causes of, iii. 713. Hydrorrhcea uteri, a. 697- Ilydro-sarcocele, iv. 996. Hydrous picens, or great water-beetle, ii. 860. Hydruzoa* a sub-class of Polypifera, iv. 18. 20— 24. characters of the sub-class, iv. 18. 20, 21. ova of, s. [1'27.] Hylubatcs agilis (gibbon), a genus of Quadrumana, iv. 195. See QUADRUMANA. characters of, iv. 195. velocity of the, iii. 456. Hymen, the, s. 710. origin, varieties, and signification of the hymen, s. 710, 711.715. its presence as evidence of virginity, s. 711. uses of, ii. II". Hy in nium of basidiosporous fungi, ?. 224. llymcnoptcra, an order of Insecta, ii. 865. characters of the order, ii. 865. nervous system of, iii. 611. 7/yo-branchial apparatus (in comparative anatomy), iii. 833. hyoid, iii. 833. branchiostegous rays, iii. 834. branchial arches, iii. 834. pharyngeal bones, iii. 834. condition of the os liyoides in Reptiles, iii. 835. metamorphosis of the o» hyoides, iii. 835. /fyo-epiglottidean ligament, iii. 104. 7/vo-glossal membrane, or ligament, iv. 1124. /fyo-glossus muscle, iii. 105. 564 ; iv. 1133. action and relations, iii. 564 ; iv. 1133. //yo- thyroid articulation, iii. 103. //yo-thyroide* lateralia ligamenta, iii. 104. ////.•-thyroid muscle, iii. 102. Hyoid apparatus of Kuminantia, s. 526. artery, iv. 1141. bone, iii. 105; iv. 1123. relations, iv. 1123. basis or body, iv. 1123. cornua, greater, iv. 1124. lesser, iv. 1124. structure, iv. 1124. development, iv. 1124. necrosis of the, iv. 1102. system of muscles, iii. 542. Hyoidean branch of the lingual artery, i. 486. of the thyroid artery, i. 485. Hyracotherium, an extinct genus of Pachydermata, which see. Hynir, anatomy of the. See PACHYDERMATA. Hyperchromatupsy, iv. 1461. Hypercemia (in morbid anatomy), ii. 825. varieties, ii. 826. ot brain, iii. 720 C. of the digestive canal, s. 408. of Fallopian tubes, s. 621. of the tissues of the ovary, s. 574. 576. HypertEsthesia, or increased sensibility of touch, iv. 1184. HYPERTROPHY (in morbid anatomy), ii. 826 ; iv. 1158. Hypertrophy of adipose tissue of mammas, iii. 254. of bones of the face, ii. 220. of the brain, iii. 719. of the cranium, i. 745. of the epiglottis, iii. 122. of the heart, ii. 03*. concentric, i. e. with diminution of capacity of the cavities, ii. 638. excentric, i. e. with dilatation or increased capa- city of the cavities, active aneurism of the heart, ii. 639. simple, i. e. without change in the capacity of the cavities, ii. 638. of the heart at birth, case of, ii. 331. of the intestinal canal, s. 418. of the liver, iii. 188. of nerves, iii. 720 G. of organs of nutrition, or increased nutrition, iii. 751. of the ovary, s. 573. of pancreas, s. 108. o! the prostate gland, iv. 154. of the scrotum, iv. 1014. of the spinal cord, iii. 714. ol the thymus gland a hypothetical cause of spasmodic croup, iii. 121. of the thyroid gland, iv. 1 1 14. of uterus, s. 687. Hyphomycetes, or thread fungi, reproductive system of, s. 224. Hypnotic experiments, iv. 693. 695, 696. 703. Hypochondria, i. 4. Hypogastric nerve, iii. 918. artery, or internal iliac, i. 386. glands, i. 387. Hupoeastric plexus of nerves, i. 181 ; iii. 918: iv. 982: s. 429.603.641. inferior, s. 430. Hypogastric region, i. 505. Ifypogaslrium, i. 4. iliac region, i. 4. pubic region, i. 4. Hypoglossal, or ninth pair of nerves, iii. 6S4. 707. 721 ; iv Hyponomeuia variabilis, ovum of, s. [113.] Hypupion or onyx, ii. 203 Hypospadias, iii. 918 ; iv. 1256. cases of, iv. 152. Hyptiprymnus, or potoroos, a genus of Maisupialia, iii characters of the genus, iii. 265. species, iii. 265, i6t>. llysiprymnus ursinus, a species of Marsupialia, iii. 265. Hysteria, causes of the globus or peculiar sense of suffoca- tion in, iii. 722 L. 722 Q. Hysterocele, s. 684. Hysteroloxia, s. 683. Hystrix cristata, or common porcupine, anatomy of the, iv. 372, et teq. dorsata, or urson, anatomy of the, iv. 377, el seq. prehensilis, or cuendu, anatomy of the, iv. 377, el stq. Ice, applied along the spine, in cases of muscular disturb- ance, iii. 721 II. Ichneumon flies (Pupophaga), ii. 865. wings of the, iii. 423. powers of flight of the, iii. 423. arrangement of Cowper's glands in the, ii. 423. Ichneumonidte, ii. 866. Ichthine, chemical composition of, s. [141.] Ichlhudine, chemical composition of, s. [141.] Ichthuline, chemical composition of, s. [141.] Ichthydtna, a family of Rotifera, iv. 401, et seq. characters and genera of, iv. 401, et teq. Ichthydium, a genus of Rotifera, Iv. 401, et seq. Ichthyology. See PISCES. Idiots, brain of, iii. 588. 718. small amount of phosphorus in the brains of idiots, iii. 588. analysis of cerebral matter of idiots, iii. 5*<8. changes which take place in the, iii. 719. fusion of the hemispheres together, iii. 719. absence of the transverse commissures, iii. 719. causes of idiotcy, iii. 719. Iguana tuberculata, iv. 265. 892. pel vis of the, s. 171. teeth of, iv. 892. Iguanidte, a family of Reptilia, iv. 265, et seq. Iguanodon, teeth of the, iv. 892—894. Ilt'o-cxcal, or ileo-colic, valve, s. 363. -colic artery, i. 195, 196; s. 379. Ileum,ii. 10; s. 341,342. development of the, s. 402. ILIAC ARTERIES, ii. 827. primitive iliac arteries, common iliacs, ii. 827. origin and course, ii. 827. relations, ii. 828. size, ii. 827. internal iliac artery, ii. 828. origin and course, ii. H28, 829. internal branches : — 1. ilio-lumbar artery, ii. 829. 2. lateral sacral artery, ii. 830. 3. middle haemprrhoidal artery, ii. 830. 4. vesical arteries, ii. 830. 5. umbilical artery, ii. 830. 6. uterine artery, ii. 831. 7. vaginal artery, ii. 831. external branches : — 1. obturator or thyroid artery, ii. 831 . 2. glutaeal, or posterior iliac, artery, ii. 833. 3. ischiatic artery, ii. 833. 4. internal pudic artery, ii. 834. branches : — external hannorrhoidal arteries, ii. 835. perineal artery, ii. 835. artery of the corpus cavernosum, ii. 836. artery of the dorsum penis, ii. 836. external iliac artery, ii. 837. origin and course, ii. 837, 838. relations, coverings, connexions, ii. 837. branches : — anterior or circumflex iliac artery, ii. 842. epigastric artery, ii. 842. methods of operation for the ligature of the external iliac arteries, ii. 844. comparative merits of the different methods, ii. 846. operations for the ligaturo of the internal iliac, ii. 848. ligature of the primitive iliac, ii. 849. Iliac abscess, case of, ii. 798. fascia, i. II, 12. 14 , ii. 231. 240. 838; s. 138. fossa, i. II. external, s. 115. internal, s. 117. 3r 3 798 GENERAL INDEX. Iliac glands.internal, or hypogastric, i. 387. regions, i. 4. or auricular, articular surface of sacrum, s. 119. spine, posterior superior, s. 115. tuberosity, s. 11". vein, common, right, iv 1412. left, iv. 1412. collateral branches, iv. 1412. external, ii. 838; iv. 1412. internal, iii. 933, 934; iv. 1412. Iliacus muscle, ii. 166; s. 137. interims, i. 11. IVo- abdominal muscle, i. //zb-hypogastric nerve, iv. 761. I/w-ligameiit, s. 124 ///o-luinbar artery, ii. 250. 829. distribution, ii. 830. ///o-lumbo-costi-abdominal muscle, i. 6. //'O-pectineal eminence, s. 115. Jttb-pectineal line, s. 117. .//z'o-pubi-costo-abdominul muscle, i. 5. 7//o- scrota! nerve, iv. 7G1. Ilium, ii. 500 ; s. 115. ala or wing of the, s. 115. crest of the, s. 114. development of, s. 120 horizontal rain us, or body, of the, s. 116. peritoneum of the, iii. 943. spinous process of, posterior superior, s. 115. superior curved line of the, s. 114. Imago, the, or perfect state of insects, ii. 880. Imbecility preceding death, i. 799. Impression, deltoid, iv. 571. gluteal, s. 115. Impulse of the heart, ii. C04. Inanition, syncope by, i. 797. Incident nerves, iii. TM H. Incineration of organic substances, iii. 794. method of performing, iii. 794, 795. Incisive bone, or intermaxillary, ii. 210. canal, ii. 208. foramen, ii. 208. Incisura acetabuli, ii. 776. helicis, ii. 551. majpris, s. Santorini, muscle, ii 553. semilunaris, lunula (coracoid process), ii. 156. Incubation See OVUM. instincts guiding, of birds, iii. 14. Crustacea, i. 785. Incubus, or night-mare, iv. 688. Incus, or anvil-bone, ii. 546. development, ii. 560. abnormal conditions, ii. 561. India, variety in the complexion of the different races of iv. 1336, 1337. Indian Archipelago, inhabitants of the, iv. 1363. elephants, iii. 858. See PACHYDERMATA. ink, the Chinese pigment so called, i. 53fi. Indicator, or extensor proprius primi digiti manus, muscle, Indigestion, causes of, i. 416. Indo-European, or Indo-Germanic, races, characters of, iv. 1348. languages, iv. 1347. Induration of the human body, i. 81. of the muscular substance of the heart, ii. 637. of pancreas, s. 109. of the spinal cord, iii. 714. See SOFTENING AND INDURATION. Infcrobranchiata, ii. 377. See GASTEROPODA. /w/ro-clavicular nerves, iv. 755. ////rrt-costaies muscles, iv. 1056. action, iv. 1056. /7//>vz-maxillary nerve, iv. 548. Infra-orbital artery, i. 490 ; ii. 227 ; iii. 93. 733. nerve, ii. 284. filaments of nerves, iv. 547. vein, iv. 1404. Infra- 01 bitar canal, ii. 208. or canine fossa, ii. 207, 208. groove, ii. 208. Infra-spinal artery, iv. 435. Infra spinatus muscle, i. 217 ; iv. 436. /w/j-rt-trochlear nerve, ii. 282 ; iii. 93. branch of nasal nerve, iii. 785. Infundibulum of base of brain, iii. 703. of cochlea, ii. 532. of kidney, iv. 238. of nasal fossa, i. 731 ; iii. 725. or pavilion, of Fallopian tube, s. 601. of right ventricle of heart, ii. 581. of Rossignol, s. 264.268. of Cephalopoda, i. 517. See CEPHALOPODA. Infusoria, theory of the first origin of, ii. 4L'0. organs of circulation in, i. 654. dif-e-tive organs of, s. 295. respiratory movements of, iv. 1018. spermatozoa in, iv. 499. ova of, s. [129.] li.t of Infusoria possessing the property of luininons- ne>s, iii. 198. Inges'a and egesta, s. 382. See Food. Ingestion, analysis of the various acts of, iii. 721 I. Ingluvies, craw or crop of birds, i. 317 ; s. 301. See AVES. functions of, ii. 11. of insects, s. 298. structure of the ingluvies of Ruminantia, s. 535. Inguinal canal, i. 7, 8. 12. glands, superficial, ii. 238. lymphatic glands, i. 308. nerve, internal, iv. 762. pouches, external and internal, i. 13. ring, ii. 840, 841. hernia, congenital, i. 508 ; s. 404. of foetus in utero, ii. 319. Inguino-cutaneuus nerve, small, iv. 762. INNOMINATA ARTERIA (human anatomy), ii. 850; iii. 580; iv. 1107. anomalies, ii. 852. ligature, ii. 852. relations, &c., ii. 850. left, iv. 819. surgical operations connected with the innominate artery, iii. 580, 581. Innominate bone, ii. 776 ; s. 114. its office, s. 114. border, superior, s. 114. anterior, s. 114. inferior, s. 1 14. posterior, s. 114. surface, external or femoral, s. 115. acetabulum, or cotyloid cavity, s. 116. descending ramus, or body, of the ischium, s. 116. horizontal ramus, or body, of the pubis, s. 116. ascendii g ramus of the ischium, s. 1 16. descending ramus of the pubis, s. 11G. obturator, or thyroid, foramen, s. llti. sub-pubic, or obturator, groove, s. 116. internal, or pelvic, surface, s. 117. iliac tuberosity, s. 117. sacral or auricular surface, s. 117. internal iliac fossa, s. 117. ilio-pectineal line, s. 117- internal structure of the innominate bone, s. 117. development of the innominate bone, s. 120. fractures of the, s. 209. Innominate fossa, ii. 550. gland, iii. 88. line, or linea ilio-pectinea, s. 127. veins, iv. 1408. right, iv. 815, 816. 1408. left, iv. 1408. collateral branches, iv. 1408. Ink-bag of cuttle-fish, i. 534 ; iv. 453. Inorganic ; analysis. See ORGANIC ANALYSIS. nuclei of intestinal calculi, iv. 84. Insalivation of food, process of, s. 397- Junction of the tongue in, iv. 1152. INSECTA, i. 110; ii. 853. ancient and modern classification of Insecta, ii. 855. character of the class, i. 246 ; ii. 859. Swammerdam's dissections of insect structures, iii. 317. definition, ii. 853, 854. table of the arrangement of Insecta according to the. system of Mr. Stephens, ii 850. Sub-class I. Mandibulata, ii. 859. Ord. I. Coleoptera, ii. 859. II. Dermaptera, ii. 863. III. Orthoptera, ii. 864. IV. Neuiopteraii. 864. V. Trichoptera, ii. 865. VI. Hymenoptera, ii. 865. VII. Strepsiptera, ii. 866. Sub-class II. Haustellata, ii. 866. Ord. VIII. Lepidoptera, ii. 866. IX. Diptera, ii. 867. X. Homaloptera, ii. 867. XI. Aphaniutera, ii. 867. XII. Aptera, ii. 868. XIII. Hemiptera, ii. 868. XIV. Homoptera, ii. 868. different states of existence, ii. 869. the egg, ii. 8C9. the larva, ii. 869 external anatomy of the larva, ii. 870. external anatomy of the head, ii. 872. organs of locomotion, ii. 873; iii. 441. mode of progression of the apode larvae, iii. 441. mode of progression of the pedate larvae, iii. 441. growth and changes of the larva, ii. 874; iii. 539. the pupa, nymph, aurelia, or chrysalis, ii. 879. the imago or perfect state, ii. 880. circulatory system, i. 651 ; ii. 976. the heart, or great dorsal vessel, ii. 976. generation, organs of, ii. 441. 990. ova of insects, s. [110.] spermatozoa of Insecta, iv. 488. mode of reproduction of, s. 33. GENERAL INDEX. 799 INSECTA — continued. derma-skeleton, ii. 881. its chemical composition, — chitine or tnto- raoline, ii. 881. it-, thirteen segments, ii. 882. abdomen, ii. 918. articulations, ii. 883. head, table of the parts and appendages of the, ii. 885. account of these, ii. 885. antennae, ii. 890. development of the head, ii. £09, internal parts of the head, ii. 892. mandibles, ii. 888. maxillae, ii. 889. mouth, ii. 897. locomotion, organs of, ii. 924 ; iii. 442. aberrations of forms in the organs of loco- motion, ii. 933. legs, ii. 931. wings, ii. 924. articulation of the wings, ii. 92G. file, ii. 928. neuration, or distribution of the tracheae in the wings, ii. 926. use of the wings of insects, iii. 539. powers cf flight of insects, iii. 419. See Mo- TION, ANIMAL. powers of leaping of insects, iii. 475. velocity of predaceous insects, iii. 443. locomotive powers ol" aquatic insects, iii. 434. thorax, ii. 911. meso-thorax, ii. 914. meta-thorax, ii. 914. pro-thorax, ii. 914. table of parts, ii. 913. muscular system, ii. 934; iii. 538. muscles of the larva, ii. 935. of the perfect insect, ii. 939. nervous system, ii. 942 ; iii. 609. development of the brain and nervous system, ii. 962. nervous system of the larva, ii. 943. nerve's of the head, ii. 945. of ihe thorax, ii. 945. of the abdomen, ii. 946. nervous system of the perfect insect, ii. 948. distribution, ii. 955. structure, ii. 952. organs of hearing, ii. 961. smell, ii. 962 ; iv. 700. touch, ii. 9G1. vision, ii. 960. optic nerves of the' compound eyes of insects, iii. 775. nutrition, organs of, ii. 965. alimentary canal of larva, ii. 966 ; s. 298. appendages of the canal, il. 973. alimentary canal of perfect insect, il. 905 ; a. 298. appendages of the canal, ii. 965. biliary apparatus of, iv. 446. ingluvies or crop, s 298. gizzard, s. 298. stomach, s. 298. hepatic cceca of, iii. 174. salivary glands of insects, iv. 431. tongues of insects, iv. 1 142. mucous coat, ii. 966. muscular coat, ii. 965. peritoneal coat, ii. 965. adipose tissue, ii. 975. anal, or proper uriniferous organs, ii. 975. respiration, organs of, ii. function of respiration, ii. 987. See RESPIRATION. Insecta, — re-piratory movements of insects, iv. 1019. tegumentary appendages,— hair, scales, spines, ii. 993. temperature of. ii. 650. hermaphroditism among, ii. 721. INSECTA — list of insects possessing the property of lumi- nousness, iii. 197. See LUMINOUSNESS, ANIMAL. dormant vitality of, iii. 157. effect of fear on some of the, iii. 7. electricity of some insects, ii. 82. instinct of congregation of insects, iii. 16. imperfect societies, iii. 16. for society alone, iii. 16. of males in the pairing season, iii. 16. for emigrating together, iii. 16. for feeding together, iii. 16. for some common work advantageous to the com- munity, iii. 16. occasional association, iii. 17. instincts guiding insects in procuring food, iii. 7. instincts guiding them in the construction of their habitations, iii. 9. habitations of " perfect societies of insects," iii. 11. INSECTIVORA, a group of Mammiferous animals, ii. 994. families, ii. 994. Erinaceadae, or hedgehog*, ii. 994. Soricidae, or shrews, ii. Talpidae, or moles, ii. 994. Tupaiadae, or Tupaia family, ii. 994. i\ OR A — continued. digestive organs, ii. 1000 ; s. 302. teeth, ii. 1000. thymus gland of, iv. 1096. muscles, ii. 998. nervous system, ii. 1002. osteology, ii. 995. pelvis of, s. 164. reproduction, organs of, ii. 1005. Weberian organ in, iv. 1417. tegumentary system, ii. 1004. provisions afforded by the Creator for Insectlvora during winter, ii. 764. Insessores, or perching birds, characters of, i. 267. Insomnia, iv. 686. serious consequences resulting from, iv. 686. Inspiration and expiration, comparative force of muscular movements of, iv. 336. 1060. See RESPIRATION. Instep, the, i. 147 ; ii. 339. Insula of Rcil, iii. 696. 698. INSTINCT, iii. 1. characteristics of the phenomena of instinct, iii. 4—6. influence of external conditions in producing new instincts, iv. 1303 definition, iii. 1. the reason of man compared with the instinct of the lower animals, iii. 2, et seq. I. Instincts designed for the preservation of the indi- vidual, iii. 7. 1 . for defence and offence, iii. 7. 2. relating to the procuring of food, iii. 7. 3. in the construction of habitations, iii. 9. 4. connected with hibernation, iii. 11. II. Instincts for the propagation and support of off- spring, iii. 13. 1. migration, iii. 13. 2. choice of place for the deposit of ova, iii. 14. 3. nidification, iii. 14. 4. incubation, iii. 14. 5. procuring nourishment and protection for the young, iii. 15. III. Instincts relating to the welfare of the race or of the animal ci cation generally, iii. 15. common to man and brutes, iii. 15. motives of action contrasted with intellect, iii 16. congregation, iii. 16. imperfect societies of insects, iii. 16. for society alone, iii. 16. of males in the pairing season, iii. 16*. for emigration, iii. 16. for feeding together, iii. 16. for some common work advantageous to the community, iii. 17. of the higher animals for various purposes, iii. 17. perfect societies of insects, as ants and bees, iii. 18. deviations of the instincts of insects, and their accommodation to circumstances, iii. 19. reasons for considering the actions of ants and bees as the result of instinct, not of reason- ing, iii. 20. instances of actions of the lower animals in which short processes of reasoning seem to have been concerned, iii. 21 — 23. acquired instincts, iii. 23. instinct viewed with respect to the part it takes in the unceasing changes going on at the earth's surface, iii. 23. free will in man, iii. 24. viewed with respect to final causes, iii. 25. adaptation of the instincts and powers of animals to their office in creation, iii. 27. evidences of Design from its effects, iii. 27, 28. Integuments. See TEGUMENTARY ORGANS. of the back, i. 367. Intellect, motives of action contrasted with, ii. 16. Intellectual progress of man, capacity for, compared with the instincts of the lower animals, iv. 1300. Intemperance, long continued, a cause of wasting of the brain, iii. 720. 9 delirium tremens, iii. 720. Intensity of the human voice, iv. 1475. Interarticular cartilages, or menisci, i. 249. ligament, iv. 1032. Intercolumnal bands, i. 5. Intercostal arteries, i. 367. 189. 193 ; iii. 248. anastomoses, i. 794. dorsal branches, i. 367. anterior, iv. 822. ; superior, iv. 824. muscles, external, iv. 334. 1043. internal, iv. 334. 1043. action of the intercostal muscles, iv. 1044. 1055. nerves, iv. 760. costo-huraeral branches of, i.360. great, of the older anatomists, s. 423. See Sym- pathetic Nerve. second, i. 217. third, i. 217- 3 F 4 800 GENERAL INDEX. Intercostal — continued. veins, i. 3G5; iv. 1400. left superior, iv. 1409. Intcr-costo-humcral nerve, iv. 760. Intercrural or iuterpeduncular space, iii. C73. Intcr-l'iininur fibro-CArtilaginous tissue, &. 125. Intcrlobular arteries, iii. 171. ducts, iii. 169. fissure of liver, iii. 166. spaces of liver, iii. 166. veins, iii. 16fi, 167. 171 ; iv. 1414. Intermaxillary bone, ii. 210. Intermittent fever, characters of the urine in, iv. 1292. Intermuicular ligaments, i. 217. external, i. 21 7. internal, i. 217. Interosseal artery, posteri r, ii. 364 ; iv. 225. xeins, palmar, iv. 1407. Intcrossci externi digitorum manus muscles, ii. 251. relations and uses, ii .522. interni digitorum manus muscles, ii. 521. relations and uses, ii. 522. pedis dorsales vel externi muscles, ii. 358. pedis plantares muscles, ii. 358. Intcrosseous costo-trans verse ligament, iv. 1032. fibro-cartilages, ii. 508. ligament, iii. 131 ; iv. 1,E06. astragalo-calcaneal, ii. 343. of tarsus, ii. 343. of carpal bones, ii. 508. of tibio-fibular articulation, iv. 1119. nerve, iv. 768. anterior, iv. 757. posterior, or muscular, of musculo-spiral nerve, iv. 759. Inter-peduncular space, or Pons Tarini, iii. 676. 703. Interspinales muscles, i. 37-J ; s. 137. Inter -spinous ligament, s. 1 21. Interstitial cellular tissue, ii. 489. Inter-transver sales colli muscles, i. 374 ; iii. 561. Inter-trochanteric line, anterior, ii. Ki5. posterior ii. 165. Jntervertebral cartilages, i. 250. disks, iv. 1022. Intestinalia of Cuvier. See ENTOZOA. Intestine, etymology of the word, s 294. small, s. 339. large, s. 362. arteries of the small intestines, lymphatics of the lower part of the, iii. 227. tnucus of, iii. 482. chemical characters of I he, iii. 482. functions of canal, in digestion, ii. 10. existence of worms in the intestines of the foetus in usero, ii. 336. effects of the lesion of the vagi upon the secretion of mucus upon the inner surface of the stomach and intestines, iii. 900. gastro-intestinal calculi, iv. 83. intestinal canal in Crustacea, i. 773. and in Fishes, iii. 981. of Rodentia, iv. 389. See STOMACH AND INTESTINE. TWra-coccygeal articulations, s. 122. -lobular veins, iv. 1414. Inlransverse muscles, iv. 820. Intumescentia gangliformis nervi facialis, ii. 554. Intus-susceplion of one germ within another, cases of, ii. 317. of intestine, s. 406. Inuns, a genus of Quadrumana, iv. 196, ct seq. See QUA- DRUMANA. Invertebrata, nerves of, iii. 600. Iodine, alleged effects of, on the testicles, iv. 993. method of determining the presence of, in organic substances, iii. 803. lolpfs of Senegal, characters of the, iv. 1352. Iris, action of, in conjunction with the eye'ids, iii. 80, 95. contraction of the pupil in sleep, iii. 80. contraction of the iris occasioned by the stimulus of light, iii. 589. Iritis, arthritic, false diagnosis of, iii. 88. Iron, method of determining the presence of, in organic substances, iii. 804. Irritability, i. 717; iii. 29. definition and use of the term, iii. 29. test of irritability, iii. 29. 35. question whether irritability belongs to the muscular fibre alone, or to the muscular and nervous com- Lined, iii. ^9. arguments drawn from phenomena observed in the heart and other involuntary muscles, iii. 29. Legallois's and Philip's experiments of removing the spinal marrow, iii. 29. experiment showing that the heart may be impressed through the ganglionic system after the removal of the brain and spinal marrow, iii. 29. cilcct of narcotics on the heart and bowels, iii. 30. vis insita in connection with vis nervosa, iii. 30. new laws of action of the vis nervosa, iii. 30. degree of irritability not the same in every orean of the body, iii. 30. Irritability — confirmed different degrees of irritability in different animals, iii. 31. relation of the degree of irritability to respiration, iii. 31. I. of the pncumatometer, iii. 31. 11. of the measure of irritability, ii. 33. difference in the duration of the beat of the heart removed from the body in the foetal, early, and adult states of the higher animals, iii. 34. duration of the beat of the heart longest on the loft side, iii. 34. experiment showing the effect of artificial respiration on the heart's beat, iii. 34. deduction that arterial blood is the necessary stimulus of the left side of the heart, but that venous blood is a sufficient stimulus of the right, iii. 35. the power of enduring suspended animation a measure of irritability, iii. 35. observations on the irritability of the heart in hiber- nating animals, iii. 35. properties of activity and tenacity of life, iii. 35. source of irritability, iii. 3G. observations of Prochaska, iii. 36. of Nysten, iii. 36. of Legallois, til. 87. experiments of Miiller, iii. 37. observations of M. Segalas on the effects of strych- nine, iii. 38. observations and experiments of the author, iii. 38. explanation of the discrepancies of former authors, iii. 39. deductions, iii. 40. application of the principle deduced to pathology, iii. 40. influence of emotion on paralytic limbs, iii. 40. influence of certain respiratory acts, iii. 40. effects of the tonic power, iii. 40. effect of strychnine on paralytic limbs, iii. 40. influence of the brain and spinal marrow respec- tively on the anterior and posterior limbs re- spectively, iii. 40. cases substantiating the foregoing observations, iii. 41. recapitulation, iii. 42. experiments of Dr. J. Reid, iii. 42. experiments testing the relation of the ganglionic system to the irritability of the viscera, iii. 43. See also CONTRACTILITY. of the arteries, i. 225. of the heart, ii. 607. 010,611. upon what does the peculiar irritability of the heart depend ? ii. 612. extinction of, a cause of death, i. 793. condition of, during hibernation, ii. 772. Irrito-contractility, iii. 29. See IKKITABILITY. Ischia, planes of the, s. 127. tuberosities of the, s. 127. Ischiatio artery, ii. 501. 833. branches, ii. 834. origin and distribution, ii. 834. jTscfob-bulbosus muscle, iii. 915. /scAfo-cavernosus muscle of the penis, ii. 446. /sc/«o-coccygaei muscles, i. 17!) ; s. 138. /scAzb-perineal muscle, iii. 929. Ischia- rectal fascia, i. 177. spaces, anatomy of the, i. 177. /scAio-sacral, or sitting, arch of pelvis, s. 139. Jschium, the, i. 177. 179. development of, s. 120. descending ramus, or body of the, s. 116. ascending ramus, s. 116. origin of the name, s. 115. spine of the, s. 115. tuberosity of the, s. 115. Ischuria renalis, suppression of excretion of urine, ii. 150. Isinglass, method of obtaining, ii. 404. 7m nippuri*. a species of polyp, iv. 32. Island of Reil, iii. 672. 696. 698. Islands, coral, mode in which they are formed and become fitted for the abode of man, iv. 33. Isthmus faucium, iii. 951 ; iv. 11 21. of thyroid gland, iv. 1102. urethrae, iv. 1247. Ivory of elephants' teeth, iii. 870. of the African elephant, iv. 924. Indian elephant, iv. 924. J. Jncobson, nerve of, ii. 554. Japetic group of languages, iv. 1347. races, complexion of, iv. 1333. See VARIETIFS OF MANKIND. Jaundice, iv. 460. 46'2. causes of, iv. 4f>6, 467. characters of the urine in, iv. 1S93. state of the blood in, i. 425. appearance of the bile-ducts in fatal cases of, ii. 150. cases of, in the foetus in utero, ii. 337. Jnna, Albinoes of, i. 84. Jai'unese, pelves of, s. 150. GENERAL INDEX. 801 Jaw, lower, ii. 207. 213. See Bone— maxillary, inferior, upper, ii. 207. pillars of the lances, iii. 951. roncenital deficiency of the under-] aw (monotia), iv. 967. See Face s TKMPORO-MAXILLAHY ARTICULATION. Jejunum, i. 14; ii. 10 ; 8. 341, 342. development of the, s. 402. peritoneum of the, iii. 043. Jelly-fish, non-existence ot muscular fibre in, iii. .'-33. Jerboa, Cape (I)ipus hersipes), or jumping ban: (lle- lamys), anatomy of the, iv. 369. 372, et seq. its powers of leaping, iii. 477. Jews, variety in the complexion of the, dependent upon the locality into which they have migrated, jv. 1330. JOINT. See ARTICULATION, and the articles under the headings of the several joints. Jugular fossa, i 732, 733. ganglion, ii. 495. process, i. 732. vein, i. 732; iii. 579. anterior, iii. 571. origin and course, iii. 571. external, ii. 227 ; iii. 571. 903. origin and couise, iii. 571. internal, iv. 815, 816. 1405, 1406. collateral branches of, iv. 140G. Julida, a family of Myriapoda, iii. 645. characters of the family, iii. 545. Julus, a genus of Aiyriapoda, iii. 545, et seq. history of the process of development of the Julus iii. 553. spermatozoa of, iv. 492. Jungermannite frondosae, vegetative system of, s. 235. first period — germination of the spores, s. 235. antheridia, s. 235. archegonia, s. 235. second period — development of the embryo, s. 236. changes preparatory to the development of the spores, s.236. K. Kabyles, characters of the, iv. 1357. Ktijffres, characters of the, iv, 1353. portrait of a Kaffre iv. 1354. Knkotrela, a section of Polygastric animals, iv. 5. Kangaroo (Macropus), a genus of . Marsupial ia, iii. 257. 266, et seq. characters of the genus, Hi. 266. construction and proportion of the, iii. 257. development of the, iii. 318, et seq. digestive organs of the, s. 303. teeth of, iv. 933, 934. mammary glands of the, iii. 251. its mode ol progression, iii. 453. its powers of leaping, iii. 477. organs of voice of the, iv. 1491. pelvis of, s. 160, 161. KIDNEY, iv. 231. 1. Renal organs in the lower animals, iv. 232. in Insects, iv. 232. in the Arachnida, iv. 232. in the Lamellibranchiata, iv. 232. in the Gasteropoda, iv. 232. among the Cephalopoda, iv. 232. in Fishes, iv. 232. in Reptiles, iv. 233. in Birds, iv. 233. kidneys of Mammalia, iv. 233. 2. Human kidney, iv. 234. form, iv. 234. dimensions and weight, iv. 234. position and relations, iv. 234. anterior surface, iv. 231.J posterior surface, iv. 235. circumference, iv. 235. extremities, iv. '235. ureter or excretory duct, iv. 235. its direction, iv. 235. its relations, iv. 235. excretion from the (urine), ii. 149. quantity passed in twenty-four hours, ii. 149. blood-vessels of the kidney, iv. 235. emulgent or renal arteries, iv. 235. emulgent or renal vein, iv. 236. lymphatics of the, iii. 227 ; iv. 236. mucous membrane of the, iii. 487. internal composition of the kidney, iii. 498. nerves, iv. 236. structure ol the kidney, iv. 23G. cortical substance, iv. 236. medullary substance, iv. 237. capsule, iv. 238. calices, infundibula, and pelvis, iv. 238. minute structure, iv. 239. tibro-cellular matrix, iv. 239. tubuli uriniferi, iv. 241. mode of injecting the tubes, iv. 241. course and termination of the tubes, iv, 242. structure of the tubes, iv. '.'42. KIDNEY —continued. Malpighiau bodies, iv. 243. two distinct systems of capillary vessels in kidneys, portal system of the kidney, iv. 250. comparison between the hepatic and renal portal circulation, iv. 251. epithelium of the kidney, iv. 252. ciliary motion of the tubes, iv. 253. epithelium of the pelvis and ureter, iv. 254. function of the Malpighian bodies and uriniferous tubes, iv. 254. 3. Pathology of the kidney, iv. 256. disease of the kidney from retention of urine, iv. 256. from renal calculi, iv. 256. from external violence, iv. 257. extension of disease from other organs to the kid- ney, iv. 257. diseases resulting from a constitutional cause, iv. 257. acute suppurative nephritis, iv. 257. acute desquamative nephritis, iv. 257. chronic desquamative nephritis, iv. 258. renal haemorrhage, iv. 261. fatty degeneration of the kidney, iv. 262. hydatids in the kidney, iv. 2«i3. cancer in the kidney, 'iv. 263. fatty infiltrations in the kidney, iv. 95. state of the blood in disease of the kidney, i. 426. renal calculi, iv. 81. softening and induration of the, iv. 712. kidneys in infancy, i. 68. influence of the spinal cord on the functions of the kidneys, iii. 721 S. Kijang, or Muntjak (Cervus muntjac), s. 508. cranium of, s. 512. Koala, a species of Marsupialia, iii. 265. Kongo, woman of, iv. 1354. Kreatine and kreatinine, normal elements of blood iv. 460. KNEE-JOINT (normal anatomy), iii. 44. arteries and veins, iii. 41. bones, iii. 44. bursae, adjacent, iii. 48. cartil iges, iii. 45. seinihmar cartilages, iii. 45. ligaments, iii. 46. mechanical functions, iii. 46. synovial capsule, iii. 46. comparative anatomy of knee-joint, iii. 48. KNEE-JOINT (abnormal conditions of), iii. 48. abnormal conditions resulting from disease, iii. 48. simple acute inflammation of the knee-joint, or arthritis genu, iii. 49. anatomical characters, iii. 53. causes of, iii. 49, 50. cases of, iii. 49. 54. symptoms of, iii. 49. 51. prognosis, iii. 53. simple chronic inflammation of the knee-joint, iii. 55. cases of, iii. 56. description of the disease, iii. 56. chronic rheumatic arthritis genu, iii. 57. anatomical characters, iii. 60. cases, iii. 58. description, iii. 57. symptoms, iii. 57. prognosis, iii. 5W. treatment, iii. 59. chronic strumous arthritis genu, or white swelling, iii. 60. anatomical characters, iii. 62. first and second stages, iii. 60. 62. prognosis, iii. 61. symptoms, iii. 60, 61. acute arthritis genu combined with acute osteitis, iii. 04. with necrosis, iii. 64. without necrosis, iii. 65. displacements occurring in chronic necrosis in the vicinity of the knee, iii. 65. of the tibia backwards, iii. 65. rotation of the tibia outwards on the femur, and of the patella on the outer condyle of the femur, iii. 65. with the tibia displaced backwards also, iii. 66. abnormal conditions resulting from accident, iii. 67. fractures, iii. 67. transverse fracture of the femur immediately above the condylcs, iii. 67. oblique fracture of the lower end of the femur, iii. 67. into the knee-joint, iii. 68. by detachment of the outer coudyle, iii. 68. by detachment of the inner condyle, iii. 68. T fracture, iii. GS. 802 GENERAL INDEX. KNEE- JOINT, abnormal conditions — continued. fractures of the tibia near the knee, iii. GO. oblique into the joint, iii. (J9. transverse, iii. 69. fracture of the patella, iii. 69. dislocations, iii. 71. of the femur from the tibia at the knee- joint, iii. 71. signs of the accident, iii. 71. of the lemur backwards, iii. 71. forwards, iii. 72. lateral luxations of the knee, iii. 72. of the femur inwards, incomplete, iii. 72. of the femur outwards, iii. 72. case of, iii. 72. dislocations of the patella, iii. 73. outwards, complete, iii. 73. inwards, iii. 73. incomplete luxation of the patella, iii. 73. luxation of the patella on its edge, iii. 74. internal derangement of the knee, iii. 75. causes, iii. 75, 76. a small fragment of the tibia (the insertion of the crucial ligament) torn up, iii. 77. rupture of the quadriceps extensor tendon from its attachment to the superior border of the patella, iii. 77. rupture of the ligamentum patellae, iii. 78. Knee-pan, ii. 168. See Patella. L. Labia. See Lips. Labia pudendi, or majora, s. 708. minora, v, interna, s. 710. abnormal anatomy of the labia, s. 714. development of labia majora, iv. 1255. Labial glands, iv. 426. morbid condition of the, iv. 426. nerves, inferior, external, ii. 294, 295. internal, ii. 295. or facial, artery, i, 486. tentacles of Cephalopoda, i. 526. See Cephalopoda. Labium leporinum duplex cum palato fisso, iv. 953. sternal labium of Arachnida, i. 203. Labour process. See Parturition. Labrida:, a family of Fishes, iii. 957. Labyrinth, membraneous, ii. 533. 536, 537. liquid of the, ii. 536. 539. blood-vessels of the, ii. 542. arteries of the, ii. 542. veins of the, ii. 543. osseous, ii. 529- 557. development and abnormal conditions of the, ii. 557, 558. See HEARING, ORGAN OF. Labyrinthic branches of olfactory nerve, iii. 732. cavity, ii. 533. liquid contained in the, ii. 536. membrane lining the, ii. 533. Labyrinthodon, teeth of, iv. 867, 868. Lacerated foramen, anterior, i. 734. posticum in basi cranii, i. 732, 733. orbital fissure, inferior, i. 728. superior, i. 728. orbital foramen, anterior, i. 728. superior, i. 728. Lacerta viridis (Lizard), nervous system of the, iii. 620. organs and mode of progression of the, iii. 449. See also Lizards. Lacertidte, a family of Reptilia, iv. 205, et seq. Lace-winged flies (Hemerobidas), ii. 865. Lachrymal artery, i. 491 ; iii. 93. 786. bones, ii. 212. borders, ii. 212. 1. superior, ii. 212. 2. inferior, ii. 212. 3. anterior, ii. 212. 4. posterior, ii. 212. connexions, ii. 212. development, ii. 212. structure, ii. 212. surfaces, ii. 212. 1. external, or orbitar, ii. 212. 2. internal, or ethmoidal, ii. 212. gland, iii. 784. influence of mental emotion on the secretion of tears, iv. 466. fossa.i. 730. nerve, ii. 282 ; iii. 93. 784. LACHRYMAL ORGANS (all the accessory or protecting parts of the eye, except the orbit and muscles), iii. 78. I. Eyelids, iii. 78. general description, iii. 78. rima palpebrarum, iii. 79. movements of the eyelids, iii. 79. winking, iii. 79. LACHRYMAL ORGANS, eyelids — continued. Meiuomian follicles, iii. 79. adaptation of the eyelids, iii. 79. canthi, iii. 79. secondary fissure of inner canthus, iii. 79. lachrymal papilla and puncture, iii. 80. lacus lachrymalis, iii. 80. lachrymal caruncle, iii. 80. plica seinilunaris, iii. 80. eyelashes, iii. 80. skin of the eyelids, iii. 80. 82. eyebrows, iii. 80. muscles of, iii. 80. See also FACE. action of the eyelids in concert with the iris, iii. 80. internal structure of the eyelids, iii. 81. tarsal ligaments, iii. 81. cartilages, iii. 81. fibrous condition of the lower tarsal cartilage in man, and of both in the lower Mammalia, iii. 81. Meibomian follicles in the substance of the tarsal cartilage, iii. 81. external palpebral ligament, iii. 81. internal palpebral ligament, iii. 81. orbicularis palpebrarum, iii. 81. levator palpebrae superioris, iii. 82. palpebral conjunctiva, iii. 82. cellular tissue of the eyelids, iii. 82. roots of the eyelashes, iii. 82 removal of the, for trichiasis, iii. 82. sebaceous follicles, iii. 82. Meibomian glands, iii. 82. comparative anatomy of, iii. 83. secretion of, iii. 83. hordeoluin, iii. 83. eyelids of the right side seen from within, iii. 83. II. Conjunctiva in general, iii. 83. palpebral and ocular conjunctiva, iii. 83. oculo-palpebral space of the conjunctiva, iii. 83. superior and interior palpebral sinuses of the con- junctiva, iii. 84. disposition of the conjunctiva at the inner canthus, iii. 84. lachrymal caruncle, iii. 84. plica semilunaris, iii. 84. membrana nictitans, iii. 85. palpebral conjunctiva, iii. 85. ocular, iii. 85. subconjunctival cellular tissue, morbid condi- tion of, iii. 85. nature of the conjunctiva, iii. 85. continuity with other parts of the mucous membrane, iii. 85. lachrymal and conjunctive] secretion, iii. 8r>. intimate structure of the palpebral conjunctiva, iii. 85. chorion, iii. 85. papillary body, iii. 85. epithelium of palpebral conjunctiva, iii. 86. intimate structure of sclerotic conjunctiva, iii. papillae (?), iii. 86. epithelium of sclerotic conjunctiva, iii. 87. conjunctival covering of the cornea, iii. 87. III. Lachrymal organs properly so called, iii. 88. 1. secreting lachrymal organs, iii. 88. lachrymal gland, iii. 88. intimate structure, iii. 89. excretory ducts, iii. 89. discovery of the, iii. 89. uses of the, iii. 89. tears, iii. 90. chemical composition of, iii. 90. 2. derivative lachrymal organs, iii. 90. lachrymal groove, iii. 90. osseous canal for the nasal duct, iii. 90. lachrymal papillae, points, and canalicules, iii. 91. lachrymal sac, iii. 91. nasal duct, iii. 92. structure, iii. 92. plicae and villi, iii. 92. secretion, iii. 92. lachryrml muscle (tensor tarsi), iii. 92. origin, iii. 92. relations, iii. 92. actions, iii. 93. nerves, iii. 93. from first division of the fifth, iii. 93. 1. frontal nerve, iii. 93. 2. nasal nerve, iii 93. 3. lachrymal nerve, iii. 93. from the second division of the fifth, iii. 93. inferior palpebral, iii. 93. external and internal branches, iii. 93. facial or portio dura of the seventh pair, iii. 93. third pair, iii. 93. blood-vessels, iii. 93. 1. arteries, iii. 93. 2. veins, iii. 94. ophthalmic, cerebral, iii. 94. facial, iii. 94. GENERAL INDEX 803 I.ICHRYMAL ORGANS — continued. Comparative anatomy and development, hi. !i4. 1. Kyelids, iii. 94. in Man, iii. 94. in Birds, iii. 95. in Chelonia, iii. 95. in Lizards, iii. 95. in Fishes, iii. 95. in Cephalopoda, iii. 95. eyebrows and eyelashes, iii. 95. in Mammalia, iii. 95. in Birds, iii 95. flocculent growth of the uvea in the horse, &c. iii. 95. 2. Conjunctiva, semilunar fold, membrana nictitans and third eyelid, lachrymal caruncle and glandule of Harder, iii. 96. oculo-palpebral space, iii. 96. in serpents, iii. 96. membrana nictitans, iii. 96. cartilage of the membrana nictitans, iii. 97. muscles, iii. 97. third eyelid of Birds, iii. 97. muscles, iii. 97. quadratus, iii. 97. pyramidalis, iii. 97. action, iii. 97. in the Owl and Parrot, iii. 97. in Chelonia and in the Frog, iii. 97. glandule of Harder, iii. 98. in Mammalia, iii. 98. in Birds iii. 98. in Reptiles, iii. 98. secretion, iii. 98. 3. Secreting and derivative lachrymal apparatus, in Mammalia, iii. 98. in Birds, iii. 98. in Reptiles, iii. 98. Sauria and Chelonia, iii. 98. Ophidia, iii. 98. lachrymal bone, iii. 99. infra-orbital glandular sacs of Ruminants, iii. 99. development of the accessory parts of the eye, iii. eyelids, iii. 99. tarsal cartilages, iii. 99. lachrymal gland, iii. S<9. inner" canthus, iii. 99. lachrymal caruncle, iii. 99. Lachrymal calculi, or dacryoliths, ir. 82. process, ii. 213. tubercle, ii. 208 ; iii. 783. Lachrymaria, or lachrymatory animalcule, iv. 13. Lachrymo-nasal canal, ii. 208. Lacing, tight, injurious effects of, on the liver, iii. 188. Laciniie, rimbria?, or morsus diaboli, of Fallopian tube, s.602. Lacinularia, a genus of Rotifera, iv. 403. formation of ephippial ovum in, s [119], C12?-] Lacrymte, or tears, iii. 90. chemical composition, iii. 90. Lactation, usually a preventive to conception, ii. 457. cessation of menstruation during, i. 440. a predisposing cause of fragility of the bones, i. 441. Lacteals, iii. 228. contents of the lacteals during digestion and at other times, iii. 228. lacteals of the intestines, iii. 229. origin of the lacteals, iii. 229. See LYMPHATIC AND LACTEAL SYSTEM. Lactic acid, iii. &00; iv. 1271. constitution and chemical properties of, iii. 800; iv. 1271. a normal element of the blood, iv. 460. Lacuna of urethra, iv. 1250. lacuna magna, iv. 12".0. diseased conditions of the, iv. 1262. of bones, iii. 85o. See OSSEOCS SYSTEM. Lacus lachrymalis, iii. 80. Lady-cow (Coccinella), ii. 863. Lagomys, or rat hare, anatomy of the, iv. 374, et seq. Laguptithalmos, or morbid retraction of the upper eyelid, iii. 79. Laguttirif, a genus of Quadrumana, iv. 210, et scq. See QCAURVMA.NA. characters of the genus, iv. 210. Laguncula repens, a species of Polypifera, iv. 56. mode of reproduction of, iv. 5(i, o7. Lambdoidal suture, i. 737- l.amellibranchinta, digestive organs of the, s. 299. renal organs of, iv. 232. LameUicornes, a tribe of Coleoptera, ii. 860. characters of the tribe, ii. 860. nervous system of the, iii. 610. Lamina cornea, iii. 675. cribrosa of Albinus ii. 185. of ethmoid, i. 731. fibrous, of valves of veins, iv. 1379. gyrorum, or tube of cochlea ii. 532. median fibrous, iv. 1134 Lamina — continued. recto-vesical, of the pelvic fascia, iii. 933. spiralis. ii. 532. Laminee of bones, iii. 849. See OSSEOUS TISSUE. of cerebellum, iii. 689, et seq. intestinales, s. 401. membranous, of the bladder in man, i. 380. of sacrum, s. 118. of vertebrae, i. 250. Laminated ligaments, ii. 264. Lamisca, a genus of Myriapoda, iii. 540, et seq Lamna, teeth of, iv. 866. Lampreys, iii. 976. teeth and parasitic habits of the, iii. 976. organs of respiration of, iii. 976. of generation of, iii. 1006. Lampris guttata, skeleton of the, iii. 963. Lampyridce, or glow-worms, ii. 862. characters, ii. 862. luminousness of. See LUMINOUSNESS, ANIMAL. Lancelet (Amphioxus lanceolatus), nervous system of the, iii. 615—617. Land-crabs, iii. 540. See Crab. Language, philological evidence of the common origin of the several races of mankind, iv. 1345. the aptotic type, as Chinese, iv. 1346. the agglutinate type, as the language of the American aborigines, iv. 134«j. the amalgamate type, as the classical languages, iv. 1346. the anaptotic type, as English, iv. 1346. princip.il groups under which the various languages may be studied, iv. 1347. affinities between the Australian and Tamulian of Southern India, iv. 1363. Laplander's cranium, iv. 13^2. Lard, chemical characters of, ii. 23'2. Larus cyanorhynchus (sea-gull), nervous system of the, iii. 622. Larva of insects, ii. 869; s. 13. external anatomy of the larva, ii. 870. external anatomy of the head, ii. 872. organs of locomotion, ii. 873; iii. 441. growth and changes of the larva, ii. 874. alimentary canal of, s. 298. emigration of the larvae of gnats in societies, iii. 16. dormant vitality of larva;, iii. 157. Laryngeal branch of the thyroid artery, i. 485. veins, iv. 1406. Laryngeal nerves, iii. 112. branches of nervus vagus, iii. 886. 893. 901. superior, iii. 886. 893. external branch, iii. 886. 890. internal branch, iii. 886. 893. vascular and cardiac branch, iii. 887. 893. inferior or recurrent laryngeal, iii. 887. 893. inferior, or recurrent, nerve, iii. 113 ; iv. 1107. superior laryngeal, iii. 112. functions of the laryngeal nerves, iii. 113. motions of the glottis during respiration, iii. 1 13. phenomena observed when the recurrent nerves are diseased, compressed, or cut, iii. 113. spasmodic closure of the rima glottidis, iii. 1 13. laryngismus stridulus, iii. 113. 124. effects of the lesion of the laryngeal nerves in en- feebling the voice, iii. 895. crowing sound after section of the inferior laryngeal nerves, iii. 894. Laryngismus stridulus, or spasmodic croup, iii. 1 13. description of the disease, iii. 124. Laryngitis, acute, iii. 115. of children, or croup, iii. 115. See Croup. of adults, iii. 116. causes of inflammation, iii. 116. chronic inflammation, iii. 118. diffuse inflammation of the cellular tissues, iii. lit. diphtherite, iii. 117. erysipelas, iii. 118. oedema of the submucous tissue, iii. 116. varieties, iii. 117. idiopathic, iii. 117. traumatic, iii. 117. oedema without evidence of inflammation, iii. 117. causes of death, iii. 117. spasm ol the glottis, iii. 117. scarlatina anginosa, or angina maligna, iii. 117. symptoms and appearance, iii. 117. sloughing, iii. 118. symptoms, iii. 117. thickening by gradual deposit, iii. 1 17. ulceration, iii. 119. idiopathic, iii. 119. sympathetic, iii. 119. from a specific or constitutional taint, — as syphilis, scrofula, mercury, or a com- bination of two or more of these, iii. 119. symptoms, iii. TJi. Laryngolomy, operation for, iii. LAKYNX < in general anatomy), iii. 100. general description, iii. 100. 804 GENERAL INDEX. LARYNX — continued. 1. cartilages, iii. 100. cricoid, iii. 101. thyroid, iii. 101. arytenoid, iii. 102. cornicula laryngis, iii. 102. cuneiform cartilages, iii. 103. epiglottis, iii. 103. 2. articulations and ligaments, iii. 103. extrinsic articulations, iii. 103. hyo-thyroid articulation, iii. 103. ligamentum thyro hyoideum medium, iii. 104. ligamenta hyo thyroidea lateralia, iii. 104. ligaments of the epiglottis, iii. 104. ligamentum thyro-epiglottideum, iii. 104. ligamentum hyo epiglottideum, iii. 104. ligamentum glosso-epiglotlideum, iii. 104. tracheo-cric )ine.al, iii. 134. course, iii. 131. relations, iii. 13-1. operations lor ligaturing, iii. 134. venae comites, iii. 131. nerve, iii. 134. deep lymphatics, iii. 134. difficulty of preserving the proper position of the fibula in fracture, iii. 134. prei aution with respect to the projecting angle which the tibia, when amputated, presents anteriorly, iii. 13ft. arteries requiring ligatures in amputation of the, iii. 135. remarks on the application of artificial legs, iii. 136. the most eligible situations for exposing the tibia in order to trephine, &c., iii. 13'i. liability of the tibia to disease, iii. 13'3. curve of the tibia, iii. 136. fracture of the leg, iii. 130. of the fibula alone, iii. 136. LEG, muscles of the, iii. 137. anterior group, iii. 137. 1. tibialis anticus, iii. 137. 2. extensor longus digitorum, iii. 137. relations, iii 137 action, iii. 137. 3. extensor proprius pollicis, iii. 137. action, iii. 137. relations, iii. 137. 4. peroneus tertius, iii. 137. relations, iii. 137. action, iii. 138. external group, iii. 138. 1. peroneus longus, iii. 138. action, iii. 138. relations, iii. 138. 2. peroneus brt-vis,iii. 138 combined action, iii. 138. posterior group, iii. 13S. — superficial layer, iii. 138. 1. gastrocnemius, iii. 138. relations, iii. 138. 2. soleus, iii. 138. relations, iii. 138. tendo Achillis, iii. 139. action, iii. 139. 3. plautaris, iii. 139. action, iii. 139. deep layer, iii. 139. 1. popliteus, iii. 139- 2. flexof longus digitorum, iii. 139. accessory muscles, iii. 13S. action, iii. 139. relations, iii. 140. 3. flexor longus pollicis, iii. 140. action, iii. 140. 4. tibialis posticus, iii. 140. See also FOOT, muscles of the. Legs of animals, motion of the, iii. 411. the legs move by the force of gravity as a pendulum, iii. 411. office of the, in the progression of man, iii. 457. legs of insects, ii. 931 ; iii. 442. See INSECTA. reproduction of legs in Crustacea, i. 760. Leguminous seeds, properties of, as loud, ii. 13; s. 394. constituents of, s. 3en. See SPLEEN. Lienculi, seu lienes succenturiati, iv. 771. Life, expectation of human, iv. 1474. duration of, and causes by which it may be lengthened or shortened, iv. 14fi9. See VITAL STATISTICS. mean duration of, iv. 1474. average duration of, the same amongst all races of mankind, iv. 1337. tenacity of, among some of the lower animals, property of, iii. 30. a-sociated with a high degree of irritability of the muscular fibre, iii. 36. LIFE, iii. 141. I. General views, iii. 141. definition, iii. 141. tendency of the changes exhibited by a living being, iii. 141. method of prosecuting the inquiry, iii. 141. 806 GENERAL INDEX. LIFE — continued- difficulty in the attainment of general laws in some departments of science, iii. 141. difficulties which beset the investigation of the laws of vital action, iii. 142. conditions required for the production of vital actions, — organised structure and stimulus, iii. 142. vital properties due to the act of organisation, iii. 142. II. History of opinions, iii. 143. abstract terms used in the earlier ages of the world expressing a vague idea of a property inherent in a body that exhibits it, iii. 143. the term life as applied by the older philosophers, iii. 143. tendencies in the unenlightened mind from which the foregoing modes of explaining vital pheno- mena have resulted, iii. 144. modification which the forementioned doctrines have undergone, iii. 144. distinctness of life and mind, iii. 144. doctrine of the vital principle put forth by Barthez, vis medicatrix naturas of Hoffman and Cullen, nisus formativus of Blumenbach, organic agent of Dr. Prout, and organic force of Miiller, iii. 145. Hunter's doctrine of the vital principle, iii. 145. precise import attached to the term, iii. 146. Dr. Prout's definition, iii. 146. III. Nature and causes of vital action, iii. 146. all changes the results of the properties of matter called into exercise by appropriate stimuli, iii. 146. functions groups of vital phenomena, iii. 146. dependence of vital actions upon external stimuli, iii. 147. every class of organs is excited to action by its particular stimuli, iii. 147. conditions of a more general nature requisite for the performance of vital actions, as heat, light, and electricity, iii. 147. analogy of vital phenomena to those of the uni- verse at large, iii. 147. illustration — the earth, solar system, and universe, iii. 147. illustration— the steam-engine, iii. 148. conclusion— vital actions the properties of organs called into action by appropriate stimuli, iii. 148. IV. Connexion between vitality and organisation, iii. 148. probability that the properties which give rise to vital action exist in all forms of matter, or at least in all of those forms of it capable of be- coming organised, iii. 148. total change effected in the properties of certain forms of matter by their entrance into new combinations due to the act of combination, as analogous to vital properties being due to the act of organisation, iii. 149. no property 'distinct from the matter which ex- hibits it, or capable of being superadded to it or abstracted from it, analogy of the magnetic properties of iron to vitality considered, iii. 149. evidence of vitality being due to the properties of matter in the condition of organised tissues, to be found in the vital actions themselves, iii. 149. the assertion that the existence of organisation implies a previous existence of life, considered, iii. 150. many actions performed by living beings common to them and inorganic matter, iii. 150. preparation of materials for organization, iii. 150. V. Changes in composition, iii. 151. formation of proximate principles, iii. 151. grounds for the assumption of a distinct set of vital affinities, iii. 151. reasons for believing that the compounds with which organic chemistry supplies us have a si- milar constitution to that of inorganic com- pounds, iii. 152. the arguments in favour of vital affinity drawn from the spontaneous decomposition of organic matter, considered, iii. 152. ^ organic matter, considered, iii. 152. presumed impossibility of artificially pro- ducing organic compounds or proximate principles, considered, iii. 153. artificial and natural conversion of gum, starch, and lignin into sugar, iii. 153. catalytic action, iii. 153. evolution of electricity during the ordinary processes of growth of plants and animals, iii. 154. inability of chemists to produce organic com- pounds probably due to their want of ac- quaintance with the form or condition in which their components must be brought together in order to enter into the desired union, iii. 154. conclusions deduced from the foregoing para- graphs of the chapter, iii. 154. LIFE — continued. VI. Vitality in a dormaut or inactive condition, iii, 154. dormant vitality of seeds, eggs, &c., iii. 155. length of time during which the dormant vita- lity may be preserved, iii. 155. dormant vitality of seeds, iii. 155. dormant vitality of eggs, iii. 156. agents which destroy the vitality of seeds and eggs such as are calculated to produce im- portant changes in their structure and com- position, iii. 156. dormant vitality of plants and animals that have attained beyond the embryo condition, iii. 156. preservation of dormant vitality due to the main- tenance of normal constitution, iii. 157. suspension of vital action under other circum- stances, iii. 157. hibernation of plants, iii. 157. hibernation of animals, iii. 157. animals enclosed in rocks and trees, iii. 158. syncope, iii. 159. suspension of vital action, in parts of the human body, iii. 159. atomic theory of Dr. Daubeny, iii. 159. Ligament, accessory, of capsular, ii. 779. alar, iv. 521. annular or orbicular, iv. 2'29. of carpus, dorsal, ii. 505. articular, i. 250. capsular, i. 250. definition, i. 250. elastic, i. 251. funicular, i. 251. uses, i. 250. astragalo-scaphoid, ii. 343. auriculae anterius, ii. 551. poster! us, ii. 551. broad, of uterus, s. 705. calcaneo-scaphoid, external, ii. 343. inferior, ii. 343. capsular (capsula fibrosa ossis femoris), ii. 778; iv. 574. coronary, of the liver, iii. 940. chondro- or costo-xiphoid, iv. 1033. coraco-humeral, or accessory, iv. 574, 575. costo-transverse, anterior of long, iv. 1032. posterior, iv. 1032. cotyloid (ligamemum cotyloideum, fibro-cartilagi- neum, labium cartilagineum acetabuli1 ii. 777. crico-thyroid, iii. 104. lateral, iii. 105. dorsal, of tarsus, ii. 343. falciform, iii. 160. of the livf r, iii. 936. 941. gastro-lineale, iv. 771. Gimbernat's, i. 5 ; s. 137. gleno-humeral, or Flood's, iv. 575 glenoid, ii. 157; iv. 573. glosso-epiglottideum, iii. 104. hyo-glossal, iv. 1124. hyo-epiglottideum, iii. 104. iliac, posterior lateral, or lateral sacro iliac of Scem- mering, s. 124. ilio-lumbar, s. 124. interosseus, iii. 131 ; iv. 1506. of tarsus, ii. 343. astragalo-calcaneal, ii. 343. lateral, of wrist-joint, external, iv. 1507. internal, iv. 1507. lumbo-sacral, or sacro-vertebral, s. 121. mucous, of knee, iii. 46. of the notch, iv. 434. odontoid, i. 732. phrenico-gastricum of Scemmering, iii. 941. phrenico-lineale seu suspensorium, iv. 771. plantar, of tarsus, ii. 343. Poupart's, i. 3*. 5 ; ii. 235, 236. 757 ; s. 137. pubic, anterior, s. 125. posterior, s. 125. superior, s. 125. inferior, s. 125. pyramidal or conoid, iii. 104. radio-carpal, anterior, iv. 1506. posterior, iv. 1506. round (ligamentum teres capitis femoris, seu liga- mentuin inter-articulare), ii. 778. round, of the liver, iii. 936. sacro-coccygeal, anterior, s. 122. posterior, s. 122. sacro-iliac, superior, s. 123. anterior, s. 123. posterior, s. 123. deep, s. 123. superficial, s. 123. inferior, or short, superficial, a. 124. sacro-sciatic, great, s. 124. 207. lesser, s. 124. 207. sacro-vertebral, or lumbo-sacral, s. 121. stellate, iv. J032. GENERAL INDEX. 807 Ligament — continued. stylo-maxillary ligament, ii. 214 ; iv. 938. sub-pubic, or ligamentum arcuatum, s. 126. 207. suspensory, iii. 926; s. 709. of liver, iii. 160. thyro-epiglottideum, iii. 10-1. thyro-hyoideum medium, iii. 104. transverse <•{ acetabulum, ii. 777. triangular, iii. 930. of urethra, iv. 1247. Ligamenta inter-vertebralia, iv. 1022. {uibo-prost.it ica media, iv. 147. lateralia, iv. 147. radi.it im disjecta, iv. 1032. sulXIava, ii. 'Jfi3 ; s. 121. subflava of the vertebrae, i. 251. su*pensoria of mammary glands, iii. 248. Ligaments in general : — essential properties and offices of, ii. 264. otticc of the ligaments with respect to locomotion, iii. 415. predominating forms, ii. 264. 1. capsular, ii. 264. ; 2. funicu)ar,Ji. 264. 3. laminated, ii. 264. Ligaments in particular : — alar, of knee, iii. 46. annular, of carpus, palmar or anterior, ii. 508. 524. annulare baseos stapidis, ii. 548. capsular, of knee, iii. 46. of carpal bones, of each row of, ii. 508. of two rows of, ii. 508. carpo-metacarpal, palmar, ii. 509. of thumh, ii. 509. lateral external, ii. 509. lateral internal, ii. 509. costo-vertebral, iv. 1032. crucial, of knee, anterior, iii. 46. posterior, iii. 46. dorsal, carpo-metacarpal, ii. 509. of thumb, ii. 509. of ear, ii. 551. of the elbow, ii. 66. false, of the bladder, ii. 387. glenoid, carpal anterior, ii. 50^. posterior, ii. 508. of hip-joint, ii. 777- hyo-thyroidea lateralia, iii. 104. iriterosseous, of carpal bones, ii. 508. inter-spinous, s. 121. of jaw-bone, lower, ii. 215. of knee-joint, iii. 46. anterior, iii. 46. alar, iii. 46, 47. capsular, iii. 46. crucial, anterior, iii. 46. posterior, iii. 46. lateral, external, iii. 46. short, iii. 46. mucous, iii. 46. posterior, iii. 46. transverse, iii. 46. lateral, of liver, iii. 160. of the liver, iii. 160. metacarpo-phalangeal, glenoid, ii.510. lateral, ii. 510. of thumb, ii. 510. palmar annular, of carpus, ii. 508. carpo-metacarpal, ii. 509. palpebral, external, iii. 81. internal, iii. 81. of pelvis, s. 121. phalangeal, of fingers, glenoid, ii. 510. lateral, ii. 510. of pisiform and cuneiform bones, ii. 508, 509. pubo prostatic, iv. 1246. round, of liver, iii. 161. of the sternum, iv. 1033. snpra-spinous, s. 121. tarsal, iii. 81. of temporo maxillary articulation, external, iv. 937. internal lateral of the same, iv. 938. capsular ligament of the same, iv. 938. thyro-arytenoid (chordae vocales), iii. 102. 105; iv. 1479. inferior and superior, iii. 105. of tibio-fibular articulations, iv. 1118. triangular, of the liver, iii. 940. utero-sacral, s. 705. of the uterus,?. 705. normal anatomy, s. 705. broad ligament, iii. 943 ; s. 705. utero-sacral ligaments, s. 705. utero-vesical ligaments, s. 705. round or sub-pubic ligaments, s. 705. yellow, ii. 2G3. Ligamentum arcuatum, or sub-pubic ligament, s. 126. externum, ii. 3. internum, ii. 3. bicorne, i. 3W) ; iv. 1407. dentatum, or serrated membrane of Gordon, iii. 615. office of the ligament, iii. 616. Ligamentum — continued. dnodeni rena'e. s. 341. hepatico-duodenale, s. 341. latum pulmonis, iv. 2. nuchar. i 732. of Pachydermata, iii. 876. patellcE, iii. 45, 46. rupture of, iii. 78. subflava, iv. 512. suspensorium penis, iii. 912. teres.ii. 777,778. Ligatures of arteries, i. 229. 234, 235. 238. effects of ligatures on veins, iv. 1396. of the tibial artery, iii. 132, 133. Light, aberration of, chromatic, iii. 33*5. correction, iii. 335. spherical, iii. 334. correction, iii. 334. Herschel's doublet, iii. 334. analogy between light and sound, ii. 566. effect produced upon the retina of a stimulus of vivid light, iv. 1445. Sir Isaac Newton's experiment, iv. 1445. influence of convex and concave lenses on the rays of light passing through them, iii. 331. intensity of the impression produced by light on the eye, iv. 1444. power of organised bodies in the giving out of light, i. presence of light an essential condition for the per- formance of vital action, iii. 147. rapidity of electric light, iv. 1444. animal light. See LUMINOUSNESS, ANIMAL. Lights. See Lungs. Lightning, action of, on the vital power of the heart i. 723. syncope by. i. 797. Limax ater (common black slugt, nervous system of the, iii. 606. maximus, tongue of, iv. 1142. Lime, method of determining the presence of, in organic substances, iii. 101. Limnias, a genus of Rotifera, iv. 403. Limpet, nervous system of the, iii. 605. pneumatic apparatus of the feet of the, iii. 445. Linen alba, i. 3*, 4*. 9, 10. 18. cervicalis, ii. 230. aspera, iii. 44. ilio- pectineal, or linea innominata, s. 117. 127. ilio-pectinea muscle, i. 5. semilunaris, i. 6. temporalis, i.729. 735. Linear transversae, i. 9. of sacrum, s. 118. Lingua. See TONGDE. Lingual artery, i. 485 ; iv. 1141. branches, iv. 1141. glands, anterior, iv. 426. posterior, iv. 426. muscles, iii. 544. 565; iv. 553. transverse, iv. 1126. vertical, iv. 1126. lateral, iv. 1126. inferior, iv. 1126. longitudinal, iv. 1126. nerve, ii. 292. 295 ; iii. 949 ; iv. 820. 1141. branch of the fifth nerve, iv. 858. 1141. branches of glosso-pharyngeal nerve, ii. 497. quinsy, iv. 1154. veins, iv. 1406. Linguatnla, ;\ genus of parasitic worms, ii. 127. organisation of, ii. 127. organs of digestion of, s. 296. Lion, organs and mode of locomotion of the, iii. 455. urine of the, iv. 1297. Lipoma, i.63; iv. 129. growth of, iv. 129. origin and course of, iv. 129. Lips, iii 949. muscles, vessels, and nerves, ii. 223 ; iii. 950. use of the lips, ii. 8; iii. 950. hare-lip, iii. 954. Liqvamen, or garum, of the Romans, iv. 862. Liquid of Cotugno, ii. 536. of membraneous labyrinth, ii. 536. 539. Liquids, use of. as diet, ii. 14. fermented liquors, ii. 14. vegetable infusions or decoctions, ii. 14. Liquor prostaticus, iv. 150. puris in which pus floats, iii. 754. seminis, iv. 472, 473. Lithates, deposit of, in urine in disease, iv. 1282. Lilhic acid, iv. 1270. constitution and chemical properties of, iv. 1270. deposits of, in urine in disease, iv. 12*2. Lithobius, a genus of Myriapoda, iii. 547, et seq. SCO, et tern. Lithotomy, operation of, iii. 923. 931. 933. surgical considerations in, i. 174. bilateral and lateral methods, iii. 932. 934. supra-pubic, operation of, i 9. situation, iii. 160. 808 GENERAL INDEX. LIVER, NOKMAL ANATOMY OF THE, ii. 1S3. 481 ; iii. I GO. form, iii. 160. position, iii. 160. relations, iii. 160. ligaments, iii. 160. coronary ligament of the, iii. 1)40. falciform ligament of the, iii. W,. '.Ml. base and apex of the ligament, iii. 936. surfaces of the falx, iii. 936. triangular ligaments of the, iii. 940, lotmlus caudatus, iii. 937. fissures, iii. 161. lobes, iii. 162. coverings, iiu 162. peritoneum of the, iii. 943. basement membrane of the, iii. 487. internal composition of the liver, iii. 497 colour, iii. 1G2. texture, iii. 163. dimensions, iii. 163. chemical analysis of human liver, iii. 163. of bullock's liver, iii. 163. varieties in form, iii. 163. of position, iii. 163. gall-bladder, iii. 164. relations, iii. 164. coats, iii. 164. excretory ducts of gal 1-b' adder and liver, iii. 161. coats, iii. 164. varieties in the gall-bladder, iii. 1G4. structure of the liver, iii. 164. the terms lobule and acinus as used by Malpighi, Miiller, and Kiernan, iii. 165. Glisson's capsule, iii. 166.^ vaginal portion, iii. 167. interlobular portion, iii. 167. lobular portion, iii. 167. portal vein, iii. 167. vaginal branches and vaginal plexus, in. 167. interlobular veins, iii. 168. lobular veins, iii. 168. abdominal and hepatic origins of the portal vein, iii. 168. hepatic duct, iii. 164. 169. vaginal ducts and vaginal plexus, iii. 169. interlobular ducts, iii. 169. lobular ducts and lobular plexus, iii. 169. termination of the biliary ducrs, iii. 170. vascularity of the biliary ducts, iii. 170. mucous membrane and follicles of the biliary ducts, iii. 171. hepatic artery, iii. 171. vaginal arteries, iii. 171. interlobular arteries, iii. 171. lobular arteries, iii. 171. distribution, iii. 171. hepatic veins, iii. 172. interlobular veins, iii. 173 sublobular veins, iii. 173. hepatic trunks, iii. 173. lymphatics, iii 173.229. deep, iii. 229. superficial, iii. 229. nerves, iii. 174. progressive development of the liver in the animal series, iii. 174. in Invertebrata, iii. 174. in Vertebrata, iii. 175. comparative anatomy of the gall bladder, iii. 176. bile secreted from arterial blood in Invertebrata, formation of portal vein in the various Vertebrate classes, anastomoses of portal and caval veins, iii. 176. hepatic veins of diving animals, iii. 176. development of the liver in the embryo, iii. 177. in the fowl, iii. 177. in the human subject, iii. 177. uses of the liver, iii. 17*. secretion of bile, iii. 178. anomalous opening of the portal vein into the vena cava, iii. 178. quantity of the bile, iii. 180. expulsion of the bile, iii. 180. uses of the bile, iii. 181. red and yellow substances of Ferrcin, iii. 181. researches of M. DuJMrdin, iii. 182. the liver in infancy, i. 68. liver in various animals, iv. 445. See under the various headings. Liver-fluke (Distomahepaticum), ii. 121. LIVER, PATHOLOGICAL ANATOMY OK THE, iii. 1^2 1. diseases of the serous mcmbiane, iii. 182. acute inflammation, or membranous hepatitis, iii. 182. chronic inflammation, iii. IH'i. depositions in the subserous tissue, iii 183. 2. diseases of the mucous membrane, iii. 183. rt. thickening, iii. 183. b. softening, iii. 183. c. haemorrhage, iii. 183. d. pus iii. 183. e. abnormal deposits, iii. 183. LIVER — continued. 3. disorders of the venous circulation, iii. 183. a. general congestion, iii. 184. b. hepatic venous congestion, iii. 1*1. c. portal venous congestion, iii. 184. errors of Miiller and Cruveilhier with regard to the structure of the liver, iii. 185, 186. 4. disorders of the biliary excretion, iii. 187. biliary congestion, iii. 187. effects of obstruction of the gall-ducts, iii. 187 5. diseases of the parenchyma, iii. 187. a. inflammation, iii. 188. b. hypertrophy, iii. 188. c. atrophy, iii. 18^. cirrhosis, iii. 188. d. softening, iii. 189. e. induration, iii. 190. /. fatty degeneration, iii. HtO. unhealthy formation of fatty matter in the liver, iv. 94. causes, iv. 95. f. abscess, iii. 190. . tubercle, iii. 192. i. scirrhus, iii. 192. scirrhous tubercle, iii. 192. tubera diffusa of Farre, iii. 193. characters of, iii. 193. k. medullary sarcoma, iii. 193. seat of origin of carcinoma, iii. 194. I. fungus haematodes, iii. 194. m. melanosis, iii. 194. 6. disorders of function, iii. 194. a. suppression of secretion of bile, iii. 194. b. alterations in the physical properties of the bile, iii. 195. c. alterations in the chemical properties of the bile, iii. 195. biliary calculi, iii. 195. d. entozoa, iii. 195. symptoms of the existence of entozoa in the liver, iii. 196. symptoms of irritation of the liver, iii. 721 H. effects of inflammatory and other lesions in the foetus in utero, ii. 331. Lizards, anatomy of, iv. 265, et seq. abdominal viscera of, iii. 942. dental system of the, iv. 889. eyelids in, iii. 95. 97. nervous system of the, iii. 620, 621. organs and mode of progression of the, iii. 449. pelvis of, s. 171. monitor of South America, teeth of the, iv. 890. scincoid, teeth of, iv. 891 tongue of, iv. 1147. Lobes of organs. See those organs, of cerebellum. See Cerebellum. of the lungs, s. 258. See Lungs; RESPIRATION, OR- CANS OF. Lobi, or head-cowls, of Pteropoda, iv. 174. Lobophyllia angulosa, a genus of Polypifera, iv. 19. Lobster, the, i. 764. See CRUSTACEA. mode of progression of the, iii. 436. nervous system of the, iii. 613. Lobular arteries, iii. 171. biliary plexus, iii. 169. ducts, iii. 169. veins, iii. 168. venous plexus, iii. 168 ; iv. 1414. Lobules of duodenal gland, s. 361. of ear, ii. 551. of kidney, iv. 233, 234. of the liver, iii. 165, 166 ; s. 309. of the lungs, s. 264. minute anatomy of the lobules, s. 266. Lobulus caudatus, iii. 161, 162. 937. quadrat us, iii. 162 ; s. 309. Spigelii, iii. 161, 162; s. 309. Locomotion, function of, in animals generally, i. 145. See MOTION, ANIMAL. manner in which the posterior columns of the spinal cord may contribute to the exercise of the locomotive functions, iii. 7';1 Q. locomotion of animalcules, iv. 5. See POLYGASTRIA. and in Crustacea, i. 761. system of Pteropoda, iv. 173. of insects, ii. 9'24. See INSECTA. in the larva of insects, ii. 873. Locus niger of the crus cerebri, iii. 647 ; 722 M. perforatus anticus of base of brain, iii. 672. Locusts (Locustidae), ii 864. association of, iii. 16, 17. their economy and mode of proceeding, iii. 17 ova of the Loligo, s. [106.] I.oligopsis guttati, i. 114. London, sanitary condition of the population of, tested by the mean age at death, iv. 1471, 1472. Longfrornes, a tribe of Insects of the order Coleoptcra, ii. 862. characters of the tribe, ii. 8G2. Longissimus dorsi muscle, i. 10. 372 ; S. 137 Longitudinal commissures of the brain, iii. 701. superior, iii. 701. GENERAL INDEX. 809 Longitudinal commissures of the brain — continued. longitudinal tracts, iii. 701. fornix, iii. 701. taenia semicircularis, iii. 702. sinus, of frontal bone, i. 729. anterior, iv. 1410. sulcus, i. 729. 73.=.. tracts of corpus callosum, iii. 674. I.migus colli muscle, iii. 5G1. l.ophiodon, anatomy of the. See PACHYDERMATA. l.ophius piscatorius, nervous system of the, iii. til 5. teeth of the. iii. 978. nostrils of, iii. 998. Lophobranchii, an order of Fishes, iii. 957. characters of the order, iii. 1)57 . Lophopus Bakeri, formation and structure of the ova of, s. [127.] crystallinus, winter ovum and embryo of, s. [128.] Loxodcs, or lip animalcules, iv. 13. bursaria. mode of reproduction of, s. 7. Lumbar arteries, i. 189. 196. 367. fascia, s. 138. 1251. ganglia, s. 425. nerves, anterior branches of, iv. 761. posterior branches ot, iv. 752. plexus of nerres, ir. 764. veins, iv. 1413. Lumbo-abdomm-3. pathological condition of the lymph, iii. 234. adventitious production of lymph vessels, iv. 142. coagulable lymph, induration matter, iv. 138. Lymphangiotis of the uterine lymphatics, s. 705. LYMPHATIC AND LACTEAL SYSTEM, i. 20 ; iii. 205. general description, iii. 206. 3 G 810 GENERAL INDEX. LYMPHATIC ATVD LACTEAL SYSTEM — continued. history of the discovery of the lymphatic vessels, i. 21; iii. 206. distribution of lymphatic vessels in the human subject, iii. 206. structure, i. 22. 34 ; iii. 208. inner tunic, iii. 208. fibrous tunic, iii. 208. Ivmph hearts of the lower animals, iii. 209. external tunic, iii. 209. valves, iii. 209. mode of origin of the lymphatics, ii;. 211. 493. lymphatic or absorbent gland*, iii. 217. blood-vessels, iii. 218. cellular tissue, iii. 218. colour, iii. 218. description, iii. 217. development, iii. 217. nerves, iii. 218. structure, iii. 218. convoluted tube, iii. 218. lymph, iii. 219. analysis of, iii. 220. microscopic appearance, iii. 221. chyle globules, iii. 221. analysis of chyle, iii. 222. taken from the thoracic duct, iii. 222. before reaching the thoracic duct, iii. 223, Descriptive anatomy, iii. 223. lacteals, iii. 228. course of lymphatic glands, iii. 223. position of lymphatic glands, iii. 224. in the lower and upper extremities, iii. 224. in the cervical region, iii. 224. on the head and face, iii. 224. in the great cavities, iii. 224. mesenteric glands, iii. 224. bronchial glands, iii. 224. thoracic duct, iii. 224. right lymphatic trunk, iii. 225. lymphatic vessels, iii. 225. of the lower extremities, iii. 225. superficial set, iii. 226. of the exterior of the lower part of the trunk and external genitals, iii. 227. course of the lymphatics in the neighbour- hood of the iliac arteries and the aorta, iii. 227. lymphatics of the testicle, iii. 227. of the kidneys, iii. 227. of the suprarenal capsules, iii. 227. of the lower part of the intestines, iii. 227. lymphatics of the stomach, iii. 229. of the pancreas, iii. 229. of the spleen, iii. 229. of the liver, iii. 229. deep, iii. 229. superficial, iii. 229. of the thorax and thoracic viscera, iii. 229. of the thoracic parities, &c , iii. 229. of the lungs, iii. 230. of the heart, iii. 230. deep-seated lymphatics of the upper extremity, iii. 230. superficial, iii 231. lymphatics of the exterior of the upper part of the trunk, iii. 231. vasa efferentia of the axillary glands, iii. 231. superficial lymphatics of the head and face, Iii. 231. deep-seated, iii. 232. uses of the lymphatics and lacteals, i. 33. LYMPHATIC SYSTEM, ABNORMAL ANATOMY, iii. 232. congenital variations from the normal distribution, iii. 232. diseased conditions of the lymphatic and lacteal vessels, iii. 233. inflammation, iii. 233. ulceration and adhesion of the valves, iii. 233. thickening of the coats, iii. '^33. varicosities, iii. 233. diseased conditions of the absorbent glands, iii. 233. inflammation acute and chronic, atrophy, iii. 233. deposits, iii. 233. tubercle, iii. 233. cancer, melanosis, and encephaloid matter, iii. 234. calcareous and carbonaceous deposits, iii. 234. changes in the lymph, iii. 231. concretions in the lymphatic vessels, iv. 89, 90. Lymphatic ganglions of the face, ii. 228. Lymphatic glands, i. 23. structure, i. 23. of arm, i. 217. axillary, i. 368. cervical i. 368, inguinal, i. 368. of external ear, ii. 556. of the face, ii. 228. See LYMPHATIC SYSTEM. Lymphatic hearts, ii. 577. Lymphatic vessels in particular : — abdominal, i. Ifi. ankle, region of the, i. 151. of bone, i. 436. of cranium, i. 748,749. of diaphragm, ii. 4. of external ear, ii. 556. of the lace, ii. 2*8. deep, of the face, ii. 228. of Fallopian tube, s. 603. of generative organs of female, s. 714. of glands, ii. 489. of the hrart, ii. 596. of the kidneys, iii. 227 ; iv. 23G. of the leg, superficial, iii. 130. of the liver, iii. 173. 2*9. deep, iii. 229. perficial, iii. 229. low of the lower part of the intestines, iii. 227. of the nose, iii. 734. of the oesophagus, iii. 759. of the pancreas, iii. 2-9. of penis, iii. 918. of pharynx and mouth, iii. 949. of prostate gland, iv. 148. of salivary glands, iv. 428. of sole of the foot, ii. 355. of the spleen, iii. 229 ; iv. 793. of the stomach, iii. 229. of tympanum, ii. 556. superficial, of head and face, iii. 231. of the suprarenal capsules, iii. 227 ; iv. 833. of the testicle, iii. 227. of the thoracic duct, iii. 229. of the thorax, iii. 229. of thyroid gland, iv. 1107. of urinary bladder, i. 387. of urethra, iv. 1254. in the female, iv. 1264. of the uterus, s. 641. of the vagina, s. 707. Lyra, the, iii. 676. 703. M. Macausi Indian, cranium of, iv. 1326. Mackarel, eyes of, iii. 1002. form of, considered with respect to its mode and organs of progression, iii. 437. hibernation of the, iii. 13. Macraucenia, an extinct genus of Pach vdermata, which see. Macropus (Kangaroos), a genus of Marsupialia, iii. 266, et seq. characters of the genus, iii. 266. Macropus major, or great Kangaroo, iii. 257. See Kanga- roo ; MARSUPIALIA. digestive organs of the, s. 303. Macrospores. See REPRODUCTION, VEGETABLE. Macrosterni, a tribe of Coleoptera, ii. 861. Macrostomum, ovum of, s. [119]. Macula cribrosa, ii. 530. Madder experiments of the growth of bone, iii. 853. See OSSEOUS SYSTEM. Madecassians, or natives of Madagascar, physical character and origin of the, iv. 13G2. Madreporidce, a family of Polypifera, iv. 19. characters of the family, iv. 19. genera of, iv. 19. Madrcphyllidce, a family of Polypifera, iv. 19. characters of the family, iv. 19. genera of, iv. 19. Mcenida:, a family of Fishes, iii. 956. Magna pollicis seu princeps artery of hand, iv. 224. Magnesia, effect of large doses of, in producing intestinal calculi, iv. 84. method of determining the presence of, in organic sub- stances, iii. 804. Magnetic effects of animal electricity, ii. 85. Magnifying power of microscopes, iii. 354. See MICRO- SCOPES. Magnitude of works of nature and art, Galileo's deductions as to the limits set to, iii. 415. Magpies, instinct of, iii. 22. Magyar race, its migration from Northern Asia to Southern Europe, and modifications ofhabits in conse- quence, iv. 1328. Mahomedauism, influence of, over the tribes of Africa which have adopted it, iv. 1353. Maize, properties of, as food, ii. 13. Malacca, Peninsula of, inhabitants of the, iv. 1361. Malacopterygii abdominales, an order of Fishes, iii. 957, et seq. characters of the order, iii. 957. Malacoptcrygii apodes, an order of Fishes, iii. 957, et seq. characters of the order, iii. 957. Malacopterygii subrachiales, an order of Fishes, iii. 'J57, et seq. characters of the order, iii. 957. Malaise, or general discomfort, iv; 1165. Malaptcrurus electricus (the Silurus of T/inna?us), ii. 81, anatomy of its electrical organs, ii. 93. GENERAL INDEX. 811 Malapterurus electricus — continued. localities inhabited by it, ii. »'2. physiological effects of its electrical discharge, ii. 84. Malar branch of lachrymal artery, iii. 786. bone, i. 728, 729 ; ii. 211. angles, ii. 211. borders, ii. 211. 1. anterior superirr, or orbifar, ii. 211. 2. anterior interior, or maxillary, H. 211, 3. posterior superior, or temporal, ii. 211. 4. posterior inferior, or masseteric border, ii. 211. connexions, ii. 211. development, ii. 212. structure, ii. 212. surfaces, ii. 211. 1. external, or facial, ii. 211. 2. internal, or temporo-zygomatic, ii. 211. 3. superior, or orbitar, ii. 211. canal, ii. 211. foramina, ii. 211. nerve, ii. 2S4 ; iii. 788. cutaneous of Meckel, ii. 284. branch of lachrymal nerve, iii. 784. process, ii. 208. ridge, ii. 208. jVfa/ayo-Polynesian group of languages, iv. 1347. Malayo- Polynesians, mental and physical characteristics of the, iv."l3'31. Malays, physical characteristics of the, iv. 1361. Malignant polypi of the uose, iii. 740. Malieolar, internal, artery, i. 150. nerves, iv. 769. Malleolus, externus, i. 147. 151. 160. internus, i. 147 ; ii- 169. Malltus, or hammer-bone, ii. 546. 547. development of, ii, 560. functions of the, ii. 573. muscle of the, or tensor tympani, ii. 545. 548. functions of the muscle, ii. -"71. abnormal conditions of the, ii. 561. Malpighian bodies, iv. 243—249. epithelium of the, iv. 250. function of the, iv. 254. Malp'ghian corpuscles, functions of the, iv. 791. of the spleen, iv. 775—779. Mamma:. See MAMMARY GLANDS. MAMMALIA,I. 117; iii. 234. characteristics derived from — the circulatory system, iii. 234. the secretory system, iii. 235. the alimentary system, iii. 235. digestive organs, s. 301. pancreas, s. 98. duodenal band, s. 98. gastro-splenic band, %. 98. salivary glands, iv. 432. tongues, iv. 1151. kidneys, iv. 233. liver, iii. 175. generative organs of, ii. 421 ; iii. 235. tne osseous system, iii. 23;"i. composition of bones, i. 438, temporo-maxillary articulation, iv. 940. nervous system, the, iii. 235. 623. the organs of sight, hearing, smell, and taste, iii.236. eyelids, iii. 95. eyebrows and eyelashes, iii. 95. g'iandule of Harder, iii 98. chiasma of the optic nerve, iii. 769. respiratory movements, iv. 1021. organs of voice, iv. 1486. an-mal heat of the, ii. 649. ciliary motion in, i. fi3l. primary classification of Mammalia, according to Aris- totle, Ray, Linnams, Pallas, and Cuvier. iii. 236 — 239. subdivisions of the primary groups according to Lin- naeus and Cuvier, iii. 241 . affinities and classification of Mammalia according to Macleay and che Quinary school, iii. '24i primary division into two sub-classes according to Owen, iii. 244. orders arranged with regard to their affinities, iii. 244. Mammary artery, iv. 822. origin and course, iv. 822. branches, iv. 822. 1. mediastinal branches, iv. 822. 2. superior phrenic, or comes nervi phrenici, iv. 822. 3. anterior intercostal arteries, iv. 822. terminal branches, iv. 823. 4. internal or abdominal branch, iii. 229. 248. iv. 823. 5. external or muscnlo-phrenica,i. 364; iv. 823. varieties of the mammary artery, iv. 823. MAMMARY GLANDS (in human anatomy), ii. 481 ; ii. 245. human mamma, iii. 246. areola, iii. 247. change in colour after impregnation, iii. 247. cuticle and cutis, iii. 247. tubercles of the areola, iii. 247. areolar tissue of the, iii. 498. MAMMARY GLANDS (In human anatomy) — continued. effect of age upon the structure and appearance of the mammae, iii. 250. internal structure of the breast, iii. 148. arteries, iii. 248. absorbents, iii. 249. ligamenta suspensoria, iii. 248. nerves, iii. 249. secerning portion of the gland, cellules, glandules, milk-tubes, reservoirs, iii. 248. veins, iii. 249 nipple, or mammilla, iii. 246. cuticle, rete mucosum, and cutis, iii. 246. form and position, iii. 246. alterations during lactation, iii. 246. glands and papillae, iii. 246. mammary glands in the male, iii. 250 ; iv. 464, 465. secretion < f milk, iv. 461. 463. vicarious secretion of milk, iv. 463. influence of the nervous system and mental emotions on the secretion of milk, iv. 464. remarkable cases, iv. 465. Mammary Glands (morbid anatomy), iii. 252. hydatids, iii. 252. hypertrophy of the adipose tissue, iii. 254. inflammation, iii. 252. malignant diseases, iii. 254. cutaneous cancer, iii. 254. scirrhus, iii. 255. carcinoma reticulare, iii. 255. alveolare, iii. 255. soft cancer, fungus baematodes, and medullary can- cer, iii. 255. carcinoma fasciculatum, iii. 256. melanosis, iii. 256. tumours, chronic mammary, iii. 253. irritable, iii. 254. sero-cystic, of Sir B. Brodie. iii. 253. calculi in the, iv. 86. fatty infiltrations in the acini of the mamma, iv. 95. Mammary Glands (in comparative anatomy), iii. 251. in the Kangaroo, iii. 251. in the Ornithorhynchus, iii. 251. in Cetacea, iii. 2dl. number of efferent ducts in various animals, iii. 252. Mammary nerves, iv. 753. veins, iv. 823. internal, iii. 249; iv. 1408. Mammilliform fibrous processes, s. 1 25. " Mammilla, or nipple, of mamma?, iii. 246. Mammillary bodies, or corpora albicantia, iii. 673. 676. 701. fibrous matter and connexions, iii. 701. structure, iii. 701. processes or papillae, iv. 237. Mammoth (Elephas primigenius), tusks of the, iv. 924. Man, least adapted of all animals for swimming, iii. 439. his mode of swimming, iii. 439, 440. locomotion of, iii. 456. See MOTION, ANIMAL. Mandibles of Insects, ii. 888. See INSECTA. of Arachnida, i. 202. Mandibulala, a sub-class of Insecta, ii. 859. Mandrill, anatomy of the, iv. 201, el seq. Manis, structure of the, ii. 47. See Eaentata. electricity of a species of, ii. 82. pelvis of the, s. 164. Manlid9. Tribe II. Entomophaga, iii. 259. Group at, Gressoria, iii. 200. Genus Myrmecobius, iii. 260. Group /3, Saltatoria, iii. 260. Genus Perameles, iii. 260. Charopns, iii. 261. Group -y, Scansoria, iii. 2»il. Gtnus Didelphis, iii. 261. 3 G 2 812 GENERAL INDEX. MARSUPIAI.M, Classification — continued. Tribe 111. Carpophaga, iii. 262. Genus Fhalangista, iii. 262. Petaurus, iii. 263. Phascolarctus, iii. 265. Tribe IV. Poephaga. iii. 265. Genus Hypsiprvmnus, iii. 265. Macropus, iii. 266. Tribe V. Rhizophaga, iii. 267. Genus Phaseolomys, iii. 267. Osteology of the Marsupialia, iii. 263. the skull, iii. 2G8. composition of the cranium, iii. 269. occipital bone, iii. 269. temporal, iii. 269. sphenoid, iii. 271. parietal, iii. 272. frontal, iii. 272. lachryma), iii. 272. nasal, iii. 272. intermaxillary, iii. 272. superior maxillary, iii. 273. perforations of the bony palate, iii. 273. cavity of the cranium, iii. 274. inferior maxilla, iii. 275. of the Phascolotherium and Thylacotherium, iii. 275. yertebral column, iii. 276. cervical vertebrae, iii. 276. dorsal, iii. 277. lumbar, iii. 278. sacrum, iii. 278. caudal vertebrae, iii. 278. thorax, iii. 280. ribs, iii. 280. sternum, iii. 280. pectoral extremities, iii. 280. scapula, iii. 280. clavicle, iii. 281. humerus, iii. 281. bones of the fore-arm, iii. 281. carpus, iii. 282. metacarpus, iii. 282. phalanges, iii. 282. pelvic extremities, iii. 282 ; 8. 159. os innominatum, iii. 283. marsupial bones, iii. 283. femur, iii. 284. patella, iii. 284. tibia, iii. 284. fibula, iii. 285. tarsus, iii. 285. metatarsus, iii. 286. Myology, iii. 287. abdominal inuscles in a male Phalanger, iii. 287. external cblique, iii. 287. internal oblique, iii.2»8. transversalis abdominis, iii. 288. pyramidalis, iii 288. cremaster, iii. 288. muscles of the pectoral extremity in Perameles lagotis, iii. 289. trapezius, iii. 289. latissimus dorsi, iii. 289. omo-anconeus, iii. 289. serratus magnus, iii. 289. supra-spinatus, iii. 289. deltoides, iii. 289. subscapularis, iii. 289. teres major, iii. 289. triceps extensor, iii. 289. pectoralis major, iii. 289. biceps, iii. 289. pronator teres, iii. 290. flexor carpi ulnaris and radialis, flexor subli- mis digitorum, iii. 290. flexor profundus, iii. 290. pronator quadratus, iii. 290. supinator longus, iii. 290. muscles of the pelvic extremity, iii. 290. in the Kangaroo ; sartorius, &c., iii. 290. in a Dasyure ; sartorius and glutei, iii. 290. in Perameles lagotis ; sartorius, rectus femo- ris, and biceps flexor cruris, iii. 290. in Dasyurus macrurus ; plantaris, soleus, tibi- alis posticus, flexor longus pollicis, flexor communis digitorum, iii. 2'.)0. in Phalangista vulpinea ; muscles of the ante- rior part of the leg, iii. 2!)) . in Perameles lagotis; gastrocnemius, soleus, and plantaris, iii. 291. nervous system, iii. 291. brain, iii. 291. spinal cord, iii. 295. organs of sense, iii. 296. digestive system, iii. 297; s. 303. mouth, iii. 297. lips, iii. 297. mast'catory muscles, iii. 297. teeth, iii. 298; iv. 933. cheek pouches, iii. 299. fauces, iii. M'9. MARSUPIALIA, digestive system — continued. alimentary canal, 'iii. 299. sebaceous follicles of the rectum, iii. 303. proper sphincter of ihe anus, iii. 303. table of the length of the intestinal canal, in a few species, iii. 304. salivary glands, iii. 304. tonsils, iii. 304. liver, iii. 304. pancreas, iii. 305. spleen, iii. 305. organs and mode of progression, iii. 453. absorbents, iii. 305. blood, iii. 305. heart, iii.3t)6. arteries, iii. 307. veins, iii. 308. respiratory organs, iii. 309. tracheal rings, iii. 309. thyroid glands, iii. 310. thymus gland, iv. 1096. larynx, iii. 310. epiglottis, iii. 310. thyroid cartilage, iii. 310. kidney, iii. 310. supra-renal glands, iii. 310. ureters and bladder, iii. 310. male organs of generation, iii. 310. testes, iii. 310. vasa deferentia, iii. 311. vesicula? seminales, iii. 311. membranous and prostatic portion of the urethra, iii. 311. Cowper's glands, iii. 311. penis, iii. 311. spermatozoa, iii. 312. erectores penis, iii. 312. retractor penis, iii. 312. levator penis, iii. 313. sphincter cloacae, iii. 313. Weberian organ, iv. 1418. female organs, iii. 313. ovaries, iii. 313. review of the female generative organs in other groups of vertebrate animals, iii. 316. uteri and vaginae in various species, iii. 316. arrangement of the vaginal rugae, &c., iii. 317. purposes answered by the different forms of the generative organs of marsupial females, iii. 317. gelatino-mucous secretion in the vagina, iii. 318. clitoris, iii. 318. development of Marsupialia, iii. 318. review of the different opinions which have been expressed on the subject, iii. 318. experiment performed with a view to ascertain thn period of uterine gestation, the structure of the fcetal envelopes, the conditions of the new-born young, &c. in the Kangaroo, iii. 321. ovarian ovum, iii. 323. examination and dissection of an embryo Kangaroo at about the twentieth day of utero-gestation, iii. 323. condition of the foetus of the Kangaroo at a later stage of uterine development, iii. 325. new-born foetus of the Kangaroo, iii. 325. new-born fcetus of Didelphys Virginiana, and sub- sequent growth of the young, iii. 325. condition of the young Kangaroo whilst in the marstipium, iii. 325. relative size of the brain of the embryo Kangaroo compared with that of the embryo of the sheep, iii. 326. traces of the umbilical vessels, urachus, &c., in the mammary foetus of Kangaroo, iii. 326. dissection of a small mammary fcetus of Kangaroo, iii. 326. larynx of the mammary fcetus of Kangaroo, iii. 327.' maturation of the mammary fcetus, iii. 327. mammary organs, iii. 327. marsupium, iii. 327. observations on the claims of the Marsupialia to be re- garded as a natural group of animals, iii. 328. table of classification of the Marsupiaiia, iii. 330. Marsupiale generation, mode of, ii. 436. Marsupium, or pouch of Marsupialia, iii. 327. development of the, iii. 327. Marsupium nigrum, or pecten in Aves, ii. 203. Mascula Sappho, ii. 686. Massa csirnea Jacobi Sylvii, ii. 358. Musseteric artery, i. 4^9. branch of inferior maxillary nerve, ii. 291. or posterior inferior, border of malar bone, ii. 21 1. or external, surface of rami of lower jaw, ii. 214. veins, iv. 1404. Mastication of food, process of, s. 397. muscles used in, iii. 542. uses of the salivary glands in, iv. 428. function of the tongue as an organ of, iv. 1152. Masticatory nerve, ii. 271. Mastfff, brain of the, iii 696. Mas/tgocerca, a genus of Kotifcra, iv. 406. GENERAL INDEX. 813 Mastodon giganteus, anatomy of the. See PACHYDERMATA. tusks of the, iv. 927. pelvis of the, ?. 156. Mastoid cells, ii. 546. foramen, i. 734. nerve, iii. 571. anterior, iv. 753. external occipital, iv. 753. process, i. 734. portion of the temporal bone, i. 734. Maternal affection, or rn^yn, general final cause of, iii. 15. Matrix, fibro-celliilar, of the kidney, iv. 239. of tubes of stomach, s. 324. Matter, organic, considered, iii. 152. See LIFE. Maturity of man, i. 76. osseous system at, i. 438. Maw, etymology of the word, s. 294, note. MaxilUe', or lesser jaws, of insects, ii. 889. office of the, ii. 889. of Arachnida, i. 202. Maxillary, or inferior dental, artery, I. 489. external, or facial artery, i. 486 ; ii. '227. internal, i. 489 ; ii. 2^7. 556 ; iii. i'3. 733. 903. branches, i. 489, 490. bone, superior, i. 728, 729 ; ii. 207; iii. 725. borders, ii. 209. 1. anterior, or naso-maxillary, ii. 209. 2. posterior, or pterygo-palatine, ii. 209. 3. inferior, or alveolar, ii. 209. connexions, ii. 209. development, ii. 209. maxillary sinus, ii. 209. os intermaxillare, ii. 210. structure, ii. 209. surfaces, ii. 207. 1 . facial, ii. 207. 2. posterior, or zygomatie, it 203. 3. internal, or naso-palatine, ii. 208. 4. superior, or orbitar, ii. 208. in the inferior animals, ii. 210. Maxillary, inferior, or lower jaw-bone, ii. 213. angles of the bone, ii. 214. body of the bone, ii. 213. borders, ii. 214. 1. upper, or alveolar, ii. 214. 2. lower, ii. 214. surfaces, ii. 213. 1. anterior, ii. 213. 2. inferior, ii. 213. connexions, ii. 215. development, ii. 215. rami, ii. 214. borders, ii. 214. 1. anterior, ii. 214. 2. posterior, ii. 214. 3. superior, ii. 214. 4. inferior, ii. 214. surfaces, ii. 214. 1. external, or masseteric, ii. 214. 2. internal, or pterygoid, ii. 214. structure, ii. 215. canal, interior, ii. 294. nerve, inferior, i. 749 ; ii. 291, 292. 294. branches, ii. 289-297. divisions, ii. 291. origin and cranial course, ii. 290, 291. superior, i. 749 ; ii. 283; iii. 787. branches, ii. 284. course, ii. 283. orbital portion of the, iii. 787. or auricular process, ii. 210. 213. sinus, or antrum Highmori, ii. 209, suture, ii. 208. tuberosity, ii. 208. vein, inte'rnal, iii. 903. 949 ; iv. 1405. Meadows, ravages of the wire-worm in, ii. 861. Meal-beetles (Tenebrionidae), ii. 863. Mcandrina cerebriformis, a species of Polypifera, iv. 36. mode of growth, iv. 37. Meandrina, genera of Polypifera, iv. 36. Measles, traces of, in the foetus in utero, ii. 333. " Measly pork," cause of, ii. 120. Meat. See MUSCLE. Meat, or flVsh, as food, s. 389. See Food. Meatus auditoriuscartilagineus-membranaceus, ii. 552 development and abnormal conditions, ii. 561. auditorius externus, i. 733. interims, i. 733. of temporal bone, internal, ii. 510. externus s. porus acousticus, ii. 552, 553. development and abnormal conditions, ii. 561. nervi meatus auditorii externi, inferior et superior, ii. 553. offiVe of the, in the function of hearing, ii. 571. 577. nasal, i. 731. middle, i. 731 ; iii. 725. superior, i. 731 ; iii. 724. urinarius, iii. 914 ; iv. 1244 ; g. 710. of female, iv. 1264. Meeker s ganglion, ii. 585. Medea (Acalepha?}, i. 39. Median artery of spinal cord, anterior, iii. 656 ; iv. 821. vein, ii. 63. 362. 524. See ELBOW. basilic, ii. 63. 361,362. cephalic, ii. 64. 361, 362. nerve, i. 217. 361 : ii. 524. 527 ; iv. 756. muscular branches, iv. 756. anterior interosseous nerve, iv. 756. palmar cutaneous branch, iv. 757. terminal digital branches of the median nerve, ir. 757. Mediastinal arteries, i. 193 ; iv. 822. Mediastinum, iv. 1. testis, iv. 977. Medical Statistics. See STATISTICS, MEDICAL. Medicaments, action of, on the system, ii. 15. Medina, or Guinea, worm, ii. 122. See ENTOZOA ; Filaria MedinensU. Medulla, or marrow of bones, i. 434. composition, i. 434. condition of, in rickets, i. 440. See Rickets. medullary membrane, i. 434, 435. See also BONE, FAT, OSTEOGENY. oblongata, i. 732 ; iii. 668. 670 : iv. 677. columns, anterior pyramidal, iii. 679« 684. olivary, iii. 679. 683, 684. corpus dentatum, iii. 683. posterior pyramidal, iii. 679. 682. course of fibres, iii. 680. restiform, iii. 679. 682. 684, interpretation of the various columns, iii. 684. definition, iii. 679. development, iii. 683. fibres of, antero-posterior, iii. 680. 685. arciform, iii. 680. decussating, iii. 680. fissure of, median anterior, iii. 679. posterior, iii. 679. nerves connected with Ihe medulla oblongata, iii. 684. shape, iii. 679. transverse sections of the medulla oblongata, iii. 6*3. sketch of the microscopic anatomy of the medull* oblongata, iii. 708. functions of the medulla oblongata, iii. 722 I. spinalis, i. 731. diseases of the, iv. 957, 958. hydrorachis, iv. 957, 958. spinata in birds, i. 300. See AVES. Medullary fungus in the muscular substance of the heart, ii. 637. sarcoma of the cranium, i. 746. of the bones of the lace, ii. 220. of liver, iii. 193. of pancreas, s. 1 12. substance of the kidney, iv. 237. Medusa aurita, organs of locomotion of, i. 39. mot iii ty and sensation of, i. 41, note f a, organs of digestion in, i. 42. organs of generation in, i. 46. Medusa, i. 35, 36. food of, i. 43. mode of reproduction of, s. 20, 21. ova of, s. [129]. structure of the integuments of, s. 485. agastric Medusae, i. 42, 43. Megalnpttra, a section of Insects of the order Neuroptera, if 865. characters of the section, ii. 865. Megalotrocha, a genus of Rotifera, iv. 402. Megalotrocha flavicans, iv. 402. Megalotroctuea, a family of Rotifera, iv. 402, ft seq. characters and genera, iv. 402. Megalosaurs, teeth of, iv. 895. Megatherium, the, ii. 47. See EDENTATA. pel vis of the, s. 162. teeth of, iv. 867- Meibomian follicles, iii. 79. 81. glands, iii. 81, 82. comparative anatomy, in. 83. hordeolum, or stye, iii. 83. secretion of, iii. 83. Melancholic temperament, iv. 931 Melanic races of man. See VARIETIES OF MANKIND. Metanosis,iv. 116. raelanic deposit, iv. 116. chemical composition, iv. 116. a. alteration of ha?matosine, iv. 117. stagnation, iv. 117. extravasation, iv. 117. chemical action, iv. 117. b. introduction of black-coloured substances from without into the lungs, iv. 117. Melanosis of absorbent gland*, iii. 234. of the adipose tissue, i. 64. in the liver, iii. 194. in the muscular substance of the heart, ii. 6"8. of scrotum, iv. 1016. of the testicle, iv. 1010. Melanotic tumours, or melanomata, iv. 128. Meles Europaea, organs of voice of the, iv. 1490. Meliceric deposits in the scalp and eyelids, iv. 97. 3c 3 GENERAL INDEX. Meliceris, i. G4; iv. 97. Melicerous degeneration of the thyroid gland, iv. 1114. Melicerta, a genus of Rotifera, iv. 403. Melidce, or Badger tribe, dentition of the, iv. 913. Melolontha vulgaris, i. 111. Melomrle, iv. 969. Membrana granulosa of ovary, s. 551. 557. nictitans of birds, i. 306 ; iii. 85. of quadrupeds, iii. 85. 96, 97. tympani, ii. 544, 545. arteries of the, ii. 556. development of, ii. 559. office of the membrane in the function of hearing, ii. 572. 574. hiatus Rivinianus, ii. 546. structure of the proper membrane, ii. 545. effect of rupture or destruction of the, on the func- tion of hearing, ii. 575. otitis of the, ii. 575. flaccida tympani, ii 546. tensa tympani, ii. 546. pupillaris, ii. 184. sterni, iv. 1033. secundaria, ii. .*533. 549. nerve to the, ii. 555. uvea, flocculent growth of the, in the horse, iii. 95. MEMBRANE (in anatomy), iii. 331. definition, iii. 331. See NERVOUS CENTRES. Membrane, false or adventitious of croup, iii. 116. fenestrated or striated, of veins, iv. 1370. fibrous, of pharynx, iii. 945. 94^. of the heart, morbid tastes of the, ii. 643. See HEART, ABNORMAL CONDITIONS OF THE. inner, of the heart, ii. 594. mucous, causes of haemorrhage from the, i. 416. of the stomach, s. 320. of the nervous centres, iii. 627. dura mater, iii. 627. pia mater, iii. 633. arachnoid, iii. 636. serous, of the abdomen. See PERITONIUM. synovial, of hip-joint, ii. 779. tubular, of nerve, iii. 591. See NERVE ; Ultimate nervous fibre. Membranous labyrinth, ii. 533. 536, 537. liquid of, ii. 536. 539. portion of urethra, iii. 925. 932. Meminna. or Pigmy Chevrotain, pelvic peculiarity of the, s. 158. 161. M^vj'l T«XU«J!J and [twiyZ, Xt-rry of Galen, iii. 331. Menmgeal apoplexy, cause of, iii. 716. arteries, inferior, iii. 630. middle, i. 489. 556. 734 : ii. 556 : iii. 630 ; iv. 1405. posterior, i. 487. 731 ; iii. 630. accessory, ii. 556. MENINGES, or membranes (in anatomy), iii. 331. 627. definition, iii. 331. See NERVOUS CENTRES. membranes of the nervous centres, iii. 627. dura mater, iii. 627. pia mater, iii. G33. arachnoid, iii. 636. Meningitis, tubercular, iii. 718. characters of the urine in, iv. 1291. Meningpsis, i. 257. Menisci, or interarticular cartilages, i. 249. 250. 255. Menopoma Alleghaniensis, pelvis of the, s. 171. cranial bones of the, i. 92. spinal column in the, i. 93, 94. Menstruation, ii. 440, 441 ; s. 644. causes, ii. 440, 441. origin of the name, ii. 440. average duration of menstrual life, s. 644. alterations in the uterus during menstruation, s. 644. and after the menstrual epoch, s. 061. epoch of the first mensti nation a proof of the physio- logical conformity of the several races of man- kind, iv. 1337. table of cases of first menstruation in Hindostan and in England, iv. 1338. exciting causes of early menstruation, iv. 1338. office of the uterus in menstruation, s. 662. periods of duration and recurrence, ii. 440 ; s. 662. quantity of menstrual fluid, ii. 440; s. 663. nature of the catamenial discharge, ii. 440 ; s. 663. composition of the menstrual fluid, analysis, s. 6U3. microscopic examination, s. 663. unmixed menstrual fluid ; analysis, s. 664. source of the menstrual fluid, s. f>65. means by which the blood escapes during healthy menstruation, s. G65. purpose of menstruation, s. 666. 670. relation of this function to the maturation and emission of ova, s. 667. constancy, amongst different races, of the frequency of the catamenial flux, iv. 1339. menstrual flux considered as a secretion, iv. 4G3. menstrual discharge regarded as' an excretion, ii. 150. effects of the suppression of the evacuation of, ii. r>o. Menstruation — continued. tendency towards an assumption of some of the pecu- liarities of the male sex consequent on the suppres- sion of the catamenia, ii. 715. vicarious menstruation, iv. 464. collections of menstrual fluid within the Fallopian tube, s. 618. interruption of menstruation a sign of conception, ii. 457. See Conception. usual cessation of menstruation during pregnancy and laciation, ii. 440. Mental character of the various races of mankind, remarks on the, iv. 1342, et scq. foramen, ii. 214. fossa, ii. 214. emotion, influence of, on the pulsation of the heart, ii. 609. impressions on the mother, effects of, on the foetus in utero, ii. 330. effect of, on pregnant women, iv. 942. death from mental emotion, i. 796. nervous actions, iii 588. actions of perception, iii. 588. common sensibility, iii. 588. special sensibility, iii. 589. actions of emotion, iii. 589. process, ii. 213. stimuli of nerves, iii. 720 K. cause of sensations, iii. 720 K. Mercury, course of, productive of apoplexy and hzemoptoe, i. 232. effect of the protracted use of, on the bones, i. 449. ulcerations of the larynx caused by, iii. 119. Mermis albicans, development of ova in, s. [122.] ni^rescens, mature ova of, s. [124.] Mesencephale. See Mesocephale. Mesentcric artery, superior, i. 189. 195 ; s. 379. inferior, i. 189.196; s. 380. glands, iii. 943. Mesenteric plexus of nerves, superior, iv. 982 ; s. 429, inferior, iv. 1414; s. 381. vein, inferior, iv. 1414 ; s. 381. superior, iv. 1414: s. 381. Mesentery, the, iii. 943 ; s. 341. layers of the, iii. 943. lelt or inferior lamina of the, i. 14. Mesian line, ii. GOO. Mesmeric or hypnotic experiments, iv. 694. 696. 703. Mesoc&cum, i. 14; iii. 943. . Mesocephale, or mesencephale, iii. 6G8. 677. 684. corpora quadrigemina, iii. 677. 685. plan of section of the mesocephale, iii. 686. pons Varolii, iii. 67-*. 685. processns cerebelli ad testes, iii. 677. 685, 686. valve of Vieussens, iii. 678. 6S5, 686. intrinsic and extrinsic elements which enter into the formation of the mesocephale, iii. 686. functions of the mesocephale, iii. 722 P. emotion, iii. 722 P. diseases connected with disturbed state of emotion, iii 722 Q. extensive sway of the mesocephale over the move- ments and sensations of the body, iii. 722 Q. sketch of the microscopic anatomy of the mesocephale, iii. 709. Mesocolon, ascending, iii. 943. iliac or sigmoidal, iii. 943. descending, iii. 943. right and left, i. 14. transverse, iii. 942 ; s. 365. layers, iii. 942, 943. Mesorectum, iii. 943 ; s. 380. Metacarpal, branch of radial artery, ii. 529. Metacarpo-phalimgesA joints, ii. 510. ligaments, ii. 510. motions of these joints, ii. 510. Metacarpus, it. 507. articulation of, ii. 507. bones of, first, second, third, fourth, and fifth, ii. 507- characters ol the, ii. 507. ligaments of, ii. 509. structure and development, ii. 507. abnormal conditions of the, ii. 511. Metagenesis, s. 13. Metamorphoses of Crustacea, i. 785. of the Anoura, i. 106. See AMPHIBIA. of insects, ii. 962. See INSKCTS. of insects, ii. 870 ; iii. 539. See INSECTA. of the os hyoides in the tadpole, iii. 835. Metatarsal articulations, ii. 345. motions of the, ii. 345. phalanges of toes, ii. 342. Metatarso-phalnngeal articulations, ii. 345. motions of the, ii. 345. Metatarsus, bones of, ii. 341. articulations, ii, 345. development, ii. 312. first, ii. 341. second, ii. 342. third and fourth, ii. 342. fifth, ii. 342. structure of the metatarsal bones, ii. 342. GENERAL INDEX. 815 Metatarsus, bones of, — continued. abnormal conditions, ii. 3-17. Melopoceros cornutus, teeth of, iv. 892. Mt'topidia, a genus of Rotifera, iv. 406. Metritis catarrhalis, s. 694. partial chronic, s. 688. parenchymatosa, s. 689. Mctrocele, s. 684. JV/c/ro-helcosis, s. 694. Metroloxia, s. 683. Metro- peritonitis, s. 703. acute and chronic, s. 687, 688. 3/^-o-phlebitis, s. 703. Metrorrhcea, s. 694. Mexico, evidences of the high degree of civilisation at- tained in former times by the natives of, iv. 1360. Microcephnlia, iv. 954. See Acrania. Microcodon, a genus of Rotifera, iv. 402. Micrometers, iii. 355. micrometer screw, iii. 355. micrometer eye-piece, iii. 355. micrometry by means of the camera lucida, iii. 356. Micronesian race", physical and mental characters of the, iv. 1361. JJicropyle of the ovum of animals, s. [137.] of insects, s. [111.] [113.] of osseous fishes, s. [101.] and in the Acephalous Mollusca, s. [108.] Johannes M tiller's discovery of the, in the ova of Holothuria, s. [125.] MICROSCOPE. iii. 331. I. Opt cal principles governing the construction of microscopes, iii. 331. influence of convex and concave lenses on the rays of light passing through them, iii. 331. sphe'rical aberration, iii. 334. correction, iii. 334. Herschel's doublet, iii. 335. chromatic aberration, iii. 335. correction, iii. 335. simple microscope, iii. 336. phenomena of ordinary vision, iii. 337. convex lens, iii. 337. Dr. Brewster's lens of diamond, sapphire, or carbuncle, iii. 337. Dr. Wollaston's doublet, iii. 333. angle of aperture, iii. 338. Coddington lens, iii. 339. Stanhope lens, iii. 339. compound microscope, iii. 339. field glass, iii. 340. Huyghenian eye-piece, iii. 341. Mr. Holland's doublet microscope, iii. 342. eye-pieces intended to increase the field, iii. 342. achromatic combinations, method of va- rying the magnifying power, iii. 343. test objects, iii. 344. penetrating power, iii. 344. defining power, iii. 344. II. Mechanical arrangements of microscopes, iii. 3-14. objects to be atta:ned 1. steadiness and firmness, iii. 344. 2. capability of accurate adjustment, iii. 345. 3. the power of placing the instrument in either a vertical or horizontal posi- tion, iii. 345. 4. simplicity, iii. 346. best means of carrying on dissections under a magnifying power, iii. 34G. dissecting instruments, iii. 346. compressorium, iii. 347. ordinary compound or simple microscope de- scribed, iii. 347. superior compound microscope, iii. 349. illumination, iii. 351. mirror, iii. 352. direct light, iii. 352. condenser, iii. 353. achromatic condenser, iii. 353. illumination of opaque objects, iii. 354. condensing mirror, iii. 354. Lieberkiihn's speculum, iii. 354. back-ground, iii. 354. III. Magnifying power of microscopes, iii. 354. measurement of the magnifying power of mi- croscopes, iii. 355. micrometers, iii. 3">5. micrometer screw, iii. 355. micrometer eye-piece, iii. 355. micrometry by means of the camera lucida, ii'i. 356. the degree of minuteness of objects which the magnifying power of the microscope renders visible, iii. 356. Microspora, mode of reproduction of the, s. 213. Micturition, immediate agent of expulsion in, iii. 721 H. part taken by the abdominal muscles in aiding, i. 17. difficult micturition in cases of disease of the prostate gland, iv. 158. Migration, instincts connected with, ill. 12, 13. migrating pigeons of America, iii. 18. propagation and support of offspring one of the object! of, iii. 13. Milk, iii. 358. nutritive properties of, ii. 13; s. 384. 391. chief varieties and peculiarities of, s. 391. analogy of milk to blood, iii. 362. colostrum, iii. 360. contamination of the milk by various ingesta, iii. 362. cow's milk, iii. 358 ; s. 391. common milk globules, cream globules, and yellow granulated corpuscles, iii. 353. butter, iii. 359 ; s. 392. casein, or cheesy matter of milk, iii. 359 ; s. 392. aposepedine, iii. 359. lactic acid, iii. 360. proportion of cream in cow's milk, iii. 360. substances found in the ashes of cow's milk, iii. 360. sugar of milk, iii. 360. human milk, iii. 361 ; s. 391. milk from the male breast, iii. 362. milk from the ass, mare, goat, sheep, and bitch, iii. 362; s. 391. method of analysing milk, iii. 811. secretion of, iv. 461. 463. vicarious secretion of milk, iv. 463. influence of mental emotions and of the nrrvoug system on the secretion of milk, iv. 464. remarkable cases, iv. 465. Milk-tubes of Mammalia, iii. 248. See MAMMARY GLANDS. Millipedes, iii. 545. Mind, connexion of mind and body, iii. 722 Z. considered as the mode of action of the soul, iii. 722 Z. connexion of the functions of the, with those of the convolutions of the brain, iii. 722 N. influence of the emotions of the, on the body, iii. 589. Dr. Wigan's doctrine of the duality of the mind, iii. 722 Z! distinction between mind and life, iii. 144. See LIFE. Minerals, component molecules of, i. 120. Mirror of microscope, iii. 351, et seq. See MICROSCOPE. Mitchell, James, the deuf, blind, and dumb man, anecdote of, iv. 702, 703. Mitral or bicuspid valve of left ventricle, ii. 583. Modifications of organised and unorganised bodies, i. 123. Modiolus of cochlea, tubulus centralis modioli, ii. 522. 531. central artery of, ii. 542. Mola botryoides, or hydatica, iv. 946. carnosa, iv. 944. cruenta, iv. 944. fungosa, iv. 944. tendinosa, iv. 944. Molar glands, iv. -126. Mole family (Talpidae), ii. 994, et seq. Afofe(Talpa), ii. 994. eyes of the mole, ii. 1003. brain of, iii. 766. development of the bony processes in the, ii. 161. pelvis of the, s. 164. Mole, Cape (Bathiergus maritimus), anatomy of the, iv. 369, et seq. Mole- cricket (Gryllotalpa vulgaris), ii. 864. Mole-rat (Spalax typhlus), anatomy of the, iv. 369, et seq. Molecular death, i. 791 ; iii. 153. See DEATH. Molecules, or elementary particles in organised and un- organised bodies, i. ! 20. Molgula, a genus of Tunicata, iv. 1187, et seq. characters of the genus, iv. 1187. Mollifies ossium, or malacosteon adultorum, i. 442 ; t. 189, 190. causes, i. 442. cases recorded, i. 442, 443. condition of the bones in, iv. 712. MOLLUSCA, iii. 363. general characters of Mollusca, iii. 363. naked mollusks, iii. 364. testaceous mollusks, iii. 364. circulatory system of Mollusca, i. 648 ; iii. 365. biliary organs of, iv. 448. classification of Mollusca, iii. 365. digestive system, iii. 365; s. 299. progressive complications of the digestive system in Mollusca. See TUNICATA ; CONCHIFERA ; PTEROPODA ; GASTEROPODA ; CEPHALOPODA. generative system, ii. 410. 417; iii. 366. mode of reproduction of, s. 22. spermatozoa in Mollusca, iv. 483. ova of Mollusca, s. [107.] muscular system, iii. 365. nervous system, iii. 364. 603. organs of the senses, iii. 364. hearing, iii. 364. sight, iii. 364. smell, iii. 364. taste, iii. 364, 3G5. touch, iii. 365. 3c 4- 816 GENERAL INDEX. MOLLUSCA — continued. respiratory system, iii. 365. uropoietic system, iii.3C6. shell of Mollusca, iv. 5G9. integuments of the Mollusca, s. 488. excretionary integument, s. 488. LOUS shell- membrane 489. substance of Dr. Carpenter, s. conversionary ii. tegument of the Mollusca con- taining cellulose, s. 493. temperature of, ii. 650. list of Mollusca possessing the property of luminous- ness, iii. 197. See LUMINOUSNESS, ANIMAL. effect of fear on some of the, iii. 7. Mollusca pinnata. See PTEROPOIJA. MelolonthidtE, ii. 860. Monad atomos of Miiller, ii. 133. Monadinidce, a family of Polygastric animals, iv. 3, el seq. characters of the family, iv. 3. Monads (Monadinidae), iv. 6. 15. their extreme minuteness, iv. 6. Mongolia tribe of Africans, woman of the, iv. 1354. Mongolian languages, iv. 1349. Mongolian race, pyramidal cranium of the, iv. 1322. physical characters of, iv. 1364. variety in the complexion of the, iv. 1334. See VA- RIETIES OF MANKIND. peninsular and hyperborean, characters of the, iv. 1351. Monitor lizard of South America, iv. 8i;0. pelvis of the, s. 171. Monkeys, iv. 195, et seq. See QUADRUMANA. organs and mode of progression of the, iii. 455. brain of, in. 624. 696. organs of voice of the, iv. 1487. Monks, alleged atrophy of the testicles of, iv. 993. Monoccra, a genus of Rotifera, iv. 404. Monochitonida, a sub class of Tunicata, iv. 1192, et seq. Monoculi, ovum of, ». [1 16.] Monolnbis, a genus of Rotifera. iv. 407. Monomyaria, i. 695. See CONCHIFERA. Monopodta, iv. 964. Monorchides. or persons with only one testicle, iv. 987. Monostoma mutabile, a species of Trematude Entozoa, ii. 142. Monostyla, a genus of Rotifera, iv.40f>. Monotia, or deficiency of the under jaw, iv. 967. MUNOTREMATA (an order of Mammalia), iii. 366. general characters, iii. 366. Echidna, iii. 367. Ornithorhynchus, iii. 367. osteology, iii. 368. skull, Echidna, iii. 368. occipital bone, iii. 369. parietal bone, iii. 369. temporal bone, iii. 370. frontal bone, iii. 370. nasal bone, iii. 370. palate bone, iii. 370. superior maxillary bone, iii. 370. comparison with the skull of various Edentate and Marsupial animals, iii. 371. skull, Ornithorhynchus, iii. 371. occipital and temporal bones, iii. 37' • parietal and frontal bones, iii. 373. foramina in the floor of the skull, iii. 373. oblique canal traversing the squamous suture, iii. 373. facial bones, iii. 373. lachrymal foramen, iii. 374. ridges on the outside of the craniam, iii. 374. interior of the skull, iii. 374. lower jaw, iii. 374. vertebral column, iii. 374. true vertebrae, iii. 374. ribs and costal cartilages or sternal ribs, iii. 375. sternum, iii. 375. sacrum, iii. 375. caudal vertebrae, iii. 375. pectoral extremities, iii. 376. pelvic extremities, iii. 378; s. 151. muscular system, Ornithorhynchus, iii. 379. nervous system, iii. 382. brain, Ornithorhynchus, ii'. 382. Echidna, iii. 382. spinal cord, Ornitliorhynchus, iii. 385. Echidna, i,i. 385. olfactory nerves, Ornithorhvnchus, iii. 385. EchHna, iii. 38X optic nerves, iii. 385. eye, iii. 385. third and fourth pair of nerves, iii. 386. fifth pair, iii. 386. sixth and seventh pair, iii. 386. acoustic nerve, iii. 386. ear, iii. 386. eighth and ninth pair of nerves, iii. 3^6. brachial plexus, median nerve, iii. 387. lumbar plexus, ischiadic nerve, iii. 3b7. digestive system, iii. 387 ; s. 304. alimentary canal, Ornithorhynchu?, iii. 387. Echidna, iii. 387. MONOTREMATA, digestive system — continued. salivary glands, iii. 388 ; iv. 433, liver, iii. 388. pancreas, iii. 388. spleen, iii. 389. circulating system, iii. 389. blood, iii. 389. heart, Ornithorhynchus, iii. 390. Echidna, iii. 390. aorta and great arterial trunks, iii. 391. venae cavae and renal veins, iii. 391. portal vein, iii. 391. respiratory system, iii. 391. lungs, iii. 391 trachea, iii. 391. l.irynx, iii. 391. thymus and other glands, iii. 391 ; iv. 1097. renal system, iii. 391. supra-renal bodies, iii. 391. kidneys, ureters, iii. 391. organs of generation, iii. 391. male organs, iii. 391. testicle, iii. 392. penis, iii. 392. levator and retractor muscles, iii. 392. Cowper's glands, iii. 392. female organs, iii. 393. ova of, s. 90. ovaries, iii. 394. Fallopian tubes and uteri, iii. 394. uro-genital canal, iii. 394. common vestibule, iii. 395. clitoris, iii. 395. Cowper's glands, iii. 395. products of generation, iii. S95. ovum, iii. 395. the young — Ornithorhynchus — external cha- racters, iii. 399. dissection, iii. 399. mammary organs, iii. 402. crural gland arid spur, iii. 405. Monotrematous generation, mode of, ii. 437. Mons Veneris, s. 2 ; i. 708. Monstrosity. See TERATOLOGY. Monura, a genus of Rotifera, iv. 406. Moon-fish (Tetrodon mola), nervous system of the, iii. 615. Moral faculties in animals generally, i. 144. Morbus coxaj, ii. 789 ; iv. 434. case of, ii. 789. morbus coxae senilis, ii. 798. Mormo maura, nervous system of the, iii. 612, 613. Morocco, Southern, characters of the Shelahs of, iv. 1357. Morsus diaboli, or fimbriaj, of Fallopian tube, s. 602. Mortality, rate of, iv. 1473. Mortification of arteries, i. 239. of bones, i. 4.03. exfoliation, i. 453. necrosis, i. 453. of the bone of the cranium, i. 756. See NECROSIS. Moschus, the, s. 508. cranium of, s. 511. Mosses, vegetative system of the, s. 237. germination of the spore, s. 238. development of the antheridia and the archegonia, s. 238. in the genus Phascum, s. 238. development of the fruit, s. 2*;8. spores, s. 239. dormant vitality of, iii. 156. Motacilla (red-start), nervous system of the, iii. 622. Mother -of -pearl, formation of, i. 712. Mother's mark, or naevus maternus, i. 242. Maths, ii. 866, 867- See Lepidoptera. changes from the larva state into that of the perfect insect, ii. 874, et seq. mode of flight of, iii. 421. MOTION, ANIMAL ; ANIMAL DYNAMICS ; LOCOMOTION ; or PROGRESSIVE MOTION OF ANIMALS, iii. 407. general remarks, iii. 407. Sect. I. Fundamental axioms, iii. 408. composition and resolution of forces, iii. 408. parallelogram offerees, iii 408. polygon of forces, iii. 408. parallelopipedon of forces, iii. 408. centre of gravity, iii. 409. the lever, iii. 410. the pulley, iii. 410. of uniform motion, iii. 411. motion uniformly varied, iii. 411. the legs move by the force of gravity as a pen- dulum, iii. 411. mechanical effects of fluids on animals immersed in them, iii. 412. resistance of fluids, iii. 413. passive organs of locomotion, iii. 413. bones, iii. 413. joints, iii. 415. ligaments, iii. 415. muscles, iii. 416. force of muscles at various stages of their con- traction, iii. 418. GENERAL INDEX. 817 MOTIOX, ANIMAL — continued. Sect. II. Flying, iii. 419. flight ofinsects, iii. 419. Coleoptera, iii. 421. Dermaptera, iii. 421. Lepidoptera, iii. 421. nocturnal Lepidnptera, iii. 422. Neuroptera, iii. 4-_'o. Hymenoptcra, iiL 423. Diptera, iii. 4-'3. table showing the areae of the wings a.id the weight of the body in various species of insects, iii. 424. flight of birds, iii. 424. use of the tail in flight, iii. 429. flight of fish and other animals, iii. 429. Dactylopterus and ExocaHus, iii. 429. Draco volans, iii. 429. Oaleopithecus and 1'teromys, iii. 430. Pterodactylus, iii. 430. Cheiroptera, hi. 430. mount of iii. 431. , . force necessary for aerial progression, Sect. III. Swimming, iii. 4J1. ciliograde animals, iii. 432. Porifera and Polypi fera, iii. 432. cirrigrade animals, iii. 4^3. pulmograile animals, iii. 433. syringograde animals, iii. 433 ; iv. 1-241. vermiform animals, iii. 431. aquatic insects, iii. 434. Decapods, iii. 436. Cephalopods, iii. 436. Pteropods, iii. 436. Pisces, iii. 437. shaped like the salmon, cod, and mackerel, iii. 437- flat fishes, iii. 437. analysis of the act of swimming in fishes, iii. 438. aquatic birds, iii. 438. quadrupeds, iii. 43y. Man, iii. 439. Sect. IV. Progression on solids, iii. 440. Radiata, iii. 440. Echiuida, iii. 440. Annelida, iii. 441. lnsecta,iii.441. apode larva? of insects, iiL 441. pedate larvae, iii. 441. perfect insects, iii. 442. Myriapoda, iii. 443. Arachnida, iii. 444, Decapoda, iii. 444. Gasteropoda, iii. 445. Cephalopoda, iii. 445. Ophidia, iii. 445. Amphibia, iii. 448. Sauria, iii. 448. Lacertae, iii. 449. Chelonia, iii. 450. birds, iii 450. mammiferous quadrupeds, iii. 451. horse, iii. 452. walk, trot, gallop, iii. 452. Marsupialia, iii. 453. Rodentia, iii 454- Ruminantia, iii. 454. Proboscidia, iii. 454. Carnivora, iii. 455. Cheiroptera, iii. 455. Quadrumana, iii. 455. Sect V. Man, iii. 456. the vertebral column, iiL 456. the legs, iii. 457. walking, iii. 459. tables of the measure of inclination of trunk in various modes of progression, iii. 460. estimate of forces employed in walking, iii. 461. running, iii. 471. the principles in which walking and running differ, iii. 471. forces employed in running, iii. 471. leaping or jumping, iii. 474. in insects, iii. 475. in quadrupeds, iii. 477. in man, iii. 478. increase of the respiration and circulation in pro- gression, iii. 479. the manner in which animal force is estimated, iii. 480. animal and vegetable motion compared, i. 137. motion of chyle granules, iii. 221. Motion, muscular, iii. 516. See MUSCULAR MOTION. Motions of joints i. 255, 256. abduction, i. 256. adduction, i. 256. circumduction, i. 256. extension, i. 256. flexion, i. 256. gliding, i. 255. rotation, i. 266. Motions of the elbow -joint, ii. 67. Motor nerves, iii. 720 H. lingua? nerve, i. 732 ; iii. 723. Motores oculorura nerves, iii. 707. Moult, or renovation of the tegumentary ske'.eton of Crustacea, i. 759. Mouth, iii. 945. See PHARYNX AND MOUTH. calculi of the mouth, iv. 82. of Cephalopoda, i. 531. of Gasteropoda, ii. 384. See GASTEROPODA. of insects, ii. 897- See INSECT A. of Marsupialia, iii. 297. Mozabite Arabs of Algiers, portraits of, iv. 1357. Mozambique, native of, iv. 1354. Muciparous follicles of vulva, s. 711. Mucous fluid lubricating the bladder, i. S86. glands of the tongue, iv 1140. Mucous MEMBRANE, iii. 484. definition, iiL 484. ultimate structure of the mucous membrane, iii. 486. basement membrane, iii. 48ti. of kidney, iii. 486. testis, iii. 487. salivary glands, iii. 487. liver, iii. 487. pulmonary air-cells, iii. 487. alimentary canal, iii. 487. skin, iii. 488. cutaneous follicles, ii. 482 ; iii. 489. epithelium, iii. 489. lamelliform or scaly variety, iii. 489. prismatic, iii. 490. spheroidal, iii. 491. non-ciliated and ciliated, iii. 492. elementary tissues appended to the mucous system, iii. blood-vessels, iii. 492. lacteal and lymphatic vessels, iii. 493. nerves, iii. 493. areolar tissue, iii. 494. of the glands, iii. 494. topographical view of the mucous system in man, iii. gastro-pulmonary tract, iii. 495. genito-urinary tract, iii. 495. peculiarities of the skin, mucous membranes, and glands, iii. 496. skin, iii. 496. raucous membranes, iii. 496. glands, iii. 497. liver, iii. 497. kidneys, iiL 498. testis, iii. 498. salivary glands, iii. 498. mammary glands, iii. 499. general outline of the functions of the mucous sys- tem, iii. 499. reception of external impressions, iii. 499. defence from external influences, iii. 499. absorption of external material, iii. 499. of the separation of material from the body, iii. 500. varieties in the qualities of the products secreted by different portions of the mucous system, iii. 503. mucus, iii. 503. conclusions, iii. 504. review of researches, iii. 504. elasticity of mucous membrane, ii. 59. not capable of adhesion, i. 54. causes of haemorrhage from the, i. 416. of liver, diseases of, iii. 183. softening of the mucous membranes, iv. 708. various kinds ot softening, iv. 709. from post-mortem causes, iv. 7C9. induration of the mucous membranes, iv. 710, 711. formation of adventitious mucous membrane, iv. 143. Mucous membrane of ca?cum, s. 363. of the colon, s. 3G8. tubes of colon, s. 368. follicles of colon, s. 368. of the nose, iii. 730. epithelium, iii. 730. course, iii. 731. of the nose, diseases of the, iiL 738, 739. of the o?sophagus, iii. 759. of small intestine, s. 343. valvulaz conniventes, s. 346. intestinal tubes, or follicles of Lieberkiihn, s. 316. villi, s. 350. intestinal follicles, s. 356. agminate, s. 356. solitary, s. 360. racemose, or Brunn's, glands, s. 361. of the stomach, s. 320. rugae, s. 320. stomach-tubes, s. 320. limitary or basement membrane which forms these tubes, s. 321. contacts of these tubes, s. 321. tubes of the cardiac extremity in the dog, 8.322. tubes at the pyloric extremity of the organ, s. 818 GENERAL INDEX. Mucous membrane — continued. trachea!, s. 259. of urethra, iv. 12-19, 1250. of the uterus, s. 635. Mucous polypi of the nose, iii. 740. Mucus, iii. 481. definition, iii. 481. general remarks, iii. 481. nose, mucus of the, iii. 481. intestinal mucus, iii. 482. urinary mucus, iii. 482. in the bile, i. 374. question of the existence of any substance to which the term mucus should be applied, iii. 483. analyses of ovarian effusions, effusion of ascites, and serum of blood, iii. 483. synthetical formation of mucus, iii. 484. mucus globules, iii. 483. varieties of the mucus globule, iii. 485. distinction between pus and mucus, iii. 484. MugillidfE, a family of Fishes, iii. 957. Mules, or hybrids, ii. 445. sterility of, ii. 445. qualities transmitted from the parents to the hybrid offspring, ii. 472. organs of voice of the, iv. 1492. Miiller, duct of, s. 594. 597. 613. Multifidus spinae muscles, i. 374. in the loins, s. 137. Mumps, or cynanche parotidea, iv. 430. effect of mumps on the testicle, iv. 993. Muntjak, or Kijang (Cervus muntjac), s. 508. cranium of, s. 512. Murcena conger, or conger, tongue of the, iv. 1146. Mus rattus, anatomy of the, iv. 371, et seq. spermatozoa of the rat, iv. 476. jaculus, or alactaga, anatomy of the, iv. 372, et seq. porcellus, or guinea-pig, anatomy_of the, iv. 372, et seq. Musca domestica (or house-fly), powers of flight of the, iii. pneumatic apparatus of the feet of, iii. 443. vomitoria (or flesh-fly), flight of the, iii. 423. 424. pneumatic apparatus of the feet of, iii. 443. thoracic spiracle of the, iv. 1504. ovum of, s. [111.] Muscnrdin (M. avellenarius), anatomy of the, iv. 386, et seq. digestive organs of the, s. 303. Muscidte, or common house-flies, iii. 867. MUSCLE, iii. 506. definition, iii. 506. general description of muscular tissue, iii. 506. characteristics of voluntary and involuntary muscles, i 719; iii. 506. contractility, i. 717. See CONTRACTILITY. a. striped elementary fibre, ii. 259 ; iii. 506. 1. length, iii. 507. 2. thickness, iii. 507. 3. figure, iii. 507. 4. colour, iii. 507. 5. internal structure, iii. 5C8. microscopical appearance, iii. 508. transverse stripes, iii. 508. longitudinal lines, iii. 508. discs, iii. 508. nbrillap, iii. 508. primitive particles, or sarcous elements. iii. 510. table of diameters, iii. 510. Dr. Barry's opinion of spiral threads, iii. 510. 6. corpuscles of elementary fibre, iii. 511. 7. sarcolemma, iii. 512. adhesion to elementary fibre, iii. 512. use, iii. 513. 8. attachment of the extremities of the fibres to other structures, iii. 513. 9. development, iii. 513. b. unstriped elementary fibres, iii. 514. c. mode of aggregation of the elementary fibres, iii. 514. connecting areolar tissue, iii. 516. blood-vessels of muscles, iii. 516. vena comites accompany ing arterial branches, iii. 516. proper capillaries, iii. 516. nerves, iii. 517. d. distribution of the striped and unstriped fibre, iii. 517. striped, iii. 517. unstriped, iii. 518. e. distribution of the striped and unstriped fibres in the animal kingdom, iii. 519. /. chemical constitution, i. 719; iii. 519. See also Fi- BIUNE. historical sketch of, iii. 527—529. relaxation of the, a sign of approaching death, i. 800. action of acids upon muscular fibre, ii. 259,260. fibres of the urethra, supposed, iii. 915. comparison of the structure of striped muscle with that of the cerebro-spirial nerve, iii. 593. Muscle (morbid states of). See HEART (morbid states of the) ; and HYPERTROPHY and ATROPHY. atrophy of muscles, various causes of, iii. 752. abnormal conditions of the muscles in chronic strumous arthritis coxa?, ii. 797. unhealthy formation of fat in the muscles, voluntary and involuntary, iv. 96. microscopic parasite of the human, ii. 113, 114. Muscles of particular organs, parts, or regions. See those organs, parts, or regions, in infancy, i. 70. in old age, i. 79. Muscles in particular : — abdominal, i. 16. abductor minimi digiti mantis, ii. 520. pedis, ii. 358. pollicis manus, ii. 519. pedis, ii. 358. acceleratores urinae, iii. 915. 929 ; iv. 1255 , s. 138. adductor brevis femoris, s. 137. longus lemoris, s. 137. magnus femoris, s. 137. ossis metacarpi, ii. 521. pollicis manus, ii. 520. pedis, ii. 358. anconasus, ii. 65. 368. anomalus of Albinus, iii. 729. of ankle, i. 150. of anus, i. 175; s. 369. aryteno-epiglottidei, iii. 110. arytenoid, iii. 101. 107. attollens auriculam, ii. 551. attrahens auriculam, ii. 552. clitoridis, s. 713. auricular, i. 749. azygos uvula?, iii. 952. basio-glossus, iv. 1133. biceps flexor cubiti, i. 216, 217. 359; ii. 63. 163. 264 363- iv. 575, 576. cruris, vel femoris, iii. 44: iv. 61. 1118: s. 137. biventer cervicis, i. 372. brachialis anticus, i. 217. 219: ii. 64, 65. 160. 363: iv 756. externus, i 220. canine, ii. 224. cerato-glossus, iv. 1133. cervicalis descendens, i. 372. chondro-glossus, iv. 1133. circumflex palati, iii. 951. coccygeo-anal, i. 176. complexus, i. 373- 732. compressor narium minor, iii. 729. nasi, iii. 7i'8. urethra?, iii. 932 ; iv. 1247 ; s. 138. vena? dorsalis penis, ii. 446; iii. 916. constrictor ani, i. 176. isthmium faucium, iii. 952; iv. 1133. of larynx, inferior, iii. 102. pharyngis inferior, iii. 946. medius, iii. 946. superior, iii. 946. vaginae, s. 712. coraco-brachialis, i. 217. 219. 359 ; ii. 160 ; iv. 756. corrugator supercilii, i. 748 ; ii. 222 ; iii. 80. costo-abdominal, i. 4*. of cranium, i. 747. 749. crernaster, i. 6. 8 ; iv. 982. 984. crico-arytenoidei postici, iii. 101. 109. laterales, iii. 101. 107. crico-thyroid, iii. 101. 105. deltoid, i. 216. 359 ; ii. 159, 160 ; iv. 435. 571. depressor alas nasi, ii. 223 ; iii. 728. anguli oris, ii. 224. labii inferioris, ii. 225. septi narium, iii. 729. urethrae, iv. 1264. detrusor urinae, i. 381. of diaphragm, ii. 1 ; iii. 544. costal, or greater, ii. 2. vertebral, or smaller— crura, pillars, or appendices, digastricus, iii. 105. 563. dilator narium, iii. 728. anterior, iii. 729. posterior, iii. 72.9. of dorsum penis, ii. 358. of ear, extrinsic, ii.551. intrinsic, ii. 552. ejaculator seminis, ii. 929. elevator auris, ii. 551. erector penis, ii. 446; iii. 915. 929 ; s. 138. clitoridis, s. 138. 709. spinee, i. 372. extensor brevis digitorum pedis, ii. 357. carpi radialis brevior, ii. 369. longior, i. 217 ; ii. 160. 366. carpi ulnaris, ii.i>69. coccygis, s. 137. cominunis digit orum, ii. 369 ; iii. 131. longus digitorum pedis, ii. 352 ; iii. 137. ossi metacarpi pollicis, ii. 369. GENERAL INDEX. 819 Muscles in particular — continued. extensor proprius pollicis pedis, ii. 352 ; iii. 137. primi digiti manui, ii. 370. primi internodii, ii. 370. secundi internodii pollicis, ii. 370. flexor brevis digitorum pedis, i. 150 ; ii. 358. minimi digiti pedis, ii. 338. minimi digiti manus, ii. 520. pollicis man (is, ii. 520. pedis, ii. 358. carpi radialis, ii. 361. 365, 366. ulnaris, ii. 367. communis digitorura perforatus, ii. 367. digitorum profundus perlbrans, ii. 368. digitorum accessorius pedis, ii. 358. communis, iii. 133. longus digitorum, iii. 139. pollicis pedis, i. 150; Hi. 133. HO. ossis metacarui, ii. 519. perforatus pedis, ii. 358. of fore-arm, ii. 63. 365. frontal, i. 747. fronto-nasal. See pyramidalis. gastrocnemius, ii. 357 ; iiL 127. 132. 138 ; iv. 62. gemellus interior, s. 138. superior, s. 138. genio-glossus, iv. 1125. genio-hyoideus, iii. 105.565. genio-hyo-glossus, iii. 565. glosso-staphylinus, iii. 952; iv. 1133. glutaeus, i. 61. maximus, ii. 833 ; 8. 137. medius, ii. 833 ; s. 137. minimus, ii. 833 ; s. 137. gracilis, s. 137. (Juthrie's, iii. 930 ; iv. 1264. helicis major, ii. 552. minor, ii. 552. hyo-glossus, iii. 105. 565; iv. 1133. hyo-thyroid, iii. 102. iliacus interims, i. 11 ; s. 137. ilio-abdominal, i. 6. ilio-lumbo-costo-abdominal, i. 6. ilio-pubi-costo-abdominal, L 4*. indicator, ii. 370. intra-costales, iv. 1056. inrra-spinatus, i. 217 ; iv. 436. intercostal, external, iv.334. 1043. internal, iv. 334 1043. action of, iv. 1044. interossei manus, ii. 521 . dorsales, ii. 521. palmares, ii. 521. pedis dorsaies, ii. 358. plantares, ii. 358. interspinales colli, i. 374 ; s. 137. intertransversales colli, i. 374 ; iii. 561. intransverse, iv. 820. ischio-cavernous of penis, ii. 446. ischio-bulbosus, iii. 915. ischio-coccygeus, s. 138. ischio-perineal.ih". 929. of joints, i. 253. lachrymal, or tensor tarsi, iiL 92. of larynx, extrinsic, iii. 105. intrinsic, iii. 105. latissimus colli, iii. 566. dorsi, L 4*. 5. 217- 362. 368 ; iv. 435. 576 ; 8. 137. laxator tympani, i. 728. of leg, iii. 137. levator anguli oris, ii. 224. scapulas, i. 370 ; iv. 576. labii superioris, ii. i?24. alaeque nasi, ii. 222. menti, ii. 225. palati, i. 734 ; iii. 951, 95S. palpebra? superioris, ii. J&2; iii. 79. 82. 784. 788. prostate, iv. 147. levatores ani, iiL 944; iv. 1246 ; s. 138, 369. costarum, iv. 344. breviores, iv. 1055. longiores, iv. 1055. lingual, iii. 544. 565 ; iv. 1126. transverse, iv. 11.6. lateral, iv. 1126 inferior, iv. 1126. longitudinal, iv. 1126. oflips, ii. 223. longissimus dorsi, i. 10. 372; 8. 137. longus colli, iii. 561. lumbo-abdominal, i. 7. lumbo-ili-abdominal, L 7. lumbricales manus, ii. 521. pedis ii. 358. malleus, external, great, ii. 548. multifidus spina?, i. 374 ; a. 137. mvlo-hyoideus, iii. 105. 564. myrtiform, ii. 223; iii. 728. nasal, ii. 222 ; iii. 727. 729. nasalis labii superioris, iii. 729. Muscles in particular — continued. naso-labialis, ii. 224. of neck, iii. 561. oblique internal, ii. 840. obliquus abdominis externus, i. 4*, 17, 18 ; 8. 137. ascendens, L 6. desccndens, i. 4*. 17. internus, i. 6. 17, 18 ; s. 137- capitis, inferior or major, i. 373 ; iii. 787. 789. superior or minor, i. 373. 732 ; iii. 784. 789. obturator externus, e. 137. internus, 137. occipital, i. 747, 748. occipito-frontalis, i. 732. 747. 749. omo-hyoid, i. 483; iii. 105. 563. opponens minimi digiti, ii. 521. pollicis, ii. 519. orbicularis oris, ii. 223. palpebrarum, ii. 221 ; iii. 80, 81. of orbit, iii. 784. orbito-palpebral, ii. 222. palato-glossus, iii. 952; iv. 1121. 1133. palato-pharyngeus, iiL 947. 952 : iv. 1121. palato-staphylinus, iii. 962. palmaris brevis, ii. 520. longus, ii. 264. 367. pectoralis major, i. 217. 359. pectineus, s. 137. minor, i. 359 ; iv. 576. of pelvis, s. 137. of penis, s. ii. 446; iii. 915. perineal, transverse, iii. 929. peristaphylinus externus, iii. 951. peroneus brevis, iii. 131. 138. longus, ii. 355. 357 ; iiL 131. 138. tertius, iii. 131. 137. pharyngeal, iii. 105. 946. pharyngeo-staphylinus, iii. 952. plantaris, iii. 132, 133. 139 ; iv. 62. platysma hyoides, i. 483; ii. 851, 852, myoides, iii. 5ti6. of popliteal region, iv. 61. popliteus, iii. 139 ; iv. 62. pronator quadratus, ii. 368. radii teres, ii. 63. 566. psoas magnus, i. 10 ; iL 838 ; s. 137. parvus, i. 11 ; iii. 838; s. 137. pterygoid, i. 727. pyramidalis abdominis, i. 10; s. 137. nasi. ii. 2^2 ; iii. 728. pyriformis, s. 137. quadratus femoris, a. 138. lumborum, L 10 ; s. 137. menti, ii. 225. quadriceps extensor, iii. 77. recti capitis antici majores, i. 732 ; iii. 561. minores, i. 732 ; iii. 561. postici majores, i. 373. 732 ; iii. 787. minores, i. 374. 732 ; iii. 787. action of the recti muscles, iii. 788. rectus capitis lateralis, i. 732 ; iii. 561. femoris, s. 137. superior, iii. 784. retractor anguli oris, iii. 566. retrahentes auriculam, iL 552. rhomboidei scapula?, iv. 576. rhomboideus major, i. 370; iii. 729 ; iv. 755. minor, L 370. risorius Santorini, iii. 566. sacro-coccygean, anterior, a. 122. posterior, s. 122. sacro-lumbalis,i. 10. 372; a. 137. sacro-spinalis, L 10. sartorius, s. 137. scalenus anticus, iii. 562 ; iv. 335. 817. posticus, iii. 562 ; iv. 335. 817. minimus, iv. 817. of scapular region, iv. 433. semi- mem branosus, iv. 61. semi-spin alis dorsi, L 372. colli, i. 373. semi-tendinosus, ii. 264 ; iv. 61 ; s. 137. serratus magnus, L 4*, 5. 361. anticus, iv. 576. minor anticus, i. 359. posticus inferior, i. 371. superior, i. 371. soleus, iii. 127. 132. 138. sphincter ani cutaneus, i. 176. externus, i. 17<3 ; s. 369. internus, L 176, 177; s. 138. 369. ii. 233. vagi me, a. 138. spinalis, or semi-spinalis, colli, i. 373. dorsi, i. 37 ~2. splenius capitis, i. 371. colli, vel cervicis, i. 371. steroo-costalis, iv. 1055. gterno-cleido-mastoideug, i. 734 ; iii. 565; iv. 817. sternc-hyoid, i. 483; ii. 851 ; iii. 102. 105. 562; iv. 1022; 8.259. oris, vagi 820 GENERAL INDEX. Muscles in particular — continued. sterno-mastoid, i. 749 ; ii. 851. sterno-thyroid, i. 483; ii. 851 ; iii. 105. 563; iv. 1022; s. 259. siibclavius, i. 360 ; iv. 755. subscapular, i. 362 ; iv. 755. supinator radii brevis, ii. 369. radii longus, i. 217 ; ii. 63. 160. 365. stylo-glossus, i. 734. stylo-hyoideus, i. 734; iii. 105. 564. stylo-pharyngeus, iii. 947. temporal, i. 729. 734. 749. tensor membrana tympani, i. 734. palati, i. 727; iii. 951. tarsi, iii. 92. tympani, i. 734 ; ii. 548. 574. vaginae femoris, ii, 264 ; s. 137. teres major, i. 217. 360. 362 ; iv. 436. minor, i 217 ; iv. 436. thyroid, iii. 101. thyro-arytenoideus, iii. 108. thyro-epiglottideus, iii. 110. thyro-hyoideus, iii. 105. 563. of testicle. See Cremaster. tibialis anticus, ii. 352; iii. 131. 137. posticus, iii. 133. 140. of tongue, iii. 604. 565 ; iv. 1125. of trachea, s. 262. trachelo-mastoideus, i. 373. 732. 734. transversalis abdominis, i. 7. 17: ii. 840; s. 137. colli, i. 373. I edis, ii. 358. transversus perinei, s. 138. trapezius, i. 369. 732; iv. 434, 435. 476. triangularis nasi, ii. 222 ; iii. 728. oris, ii. 225. sterni, iv. 1022. 1055. triceps extensor cubiti, i. 21fi, 217. 362. surae of Meckel, iii. 132. 139. urethral, iv. 1247. 1251. vastus externus, iii. 44. internus, iii. 44. vertebral, or smaller, of diaphragm, ii. 3. Wilson's, iii. 932. zygomaticus major, ii. 224. minor, ii. 224. MUSCULAR MOTION, iii. 519. a. contractility of muscle, i. 716; ii. 59; iii. 519. 1. is it a property inherent in muscular fibre? — doctrine of the " vis insita " of Haller, iii. 519. 2. source of contractility — whence derived? iii. 520. relation of contractility to the state of nutri- tion of the organ, iii. 520. Dr. John Reid's experiments, iii. 520. evidence furnished by cases of cerebral paraly- sis, iii. 521. corroborations furnished by the fact that throughout the animal kingdom the vascular supply is accurately proportioned to the mus- cular irritability, iii. 521. comparative power of muscles in the same animal, iii. 416. Borelli's approximate values of the powers of the muscles of the human body, iii. 417. force of muscles at various stages of their contrac- tion, iii. 418. b. stimuli of muscular contraction, i. 717; iii. 521. remote, iii. 522. immediate, iii. 522. c. visible changes occurring in muscle during contrac- tion, iii. 522. 1. of changes essential to the act, iii. 522. in the whole organ, iii. 522. in the elementary fibre, iii. 522. in the discs, iii. 523. in the fibrilhe, iii. 523. 2. on active and passive contraction, iii. 524. passive contraction, iii. 524. active contraction, iii. 514. muscular fatigue, iii. 524. 3. of the difference between the minute movements of muscles in passive and active contraction, iii. 524. in passive contraction, iii. 524. in active contraction, iii. 524. phenomena presented during contraction, iii. 524—526. emission of sound, iii. 526. development of heat, iii. 526. appearances presented by ruptured muscle, iii. motility of muscular fibre in hibernation, ii. 773. irritability of muscles, iii. 29. See IRRITABILITY. degree of irritability of muscular fibre, iii. 33. augmentation of the irritability of the muscles during sleep, ii. 766. office of the muscles with respect to locomotion, iii. 416. muscular power of some of the lower animals, i. 719. history of opinion as to the nature of muscular contrac- tion, iii. 527—529. muscular sensations, i. 717, et scq. MUSCULAR MOTION — continued. mental and physical stimuli, i. 718. See CONTRACTILITY. MUSCULAR SYSTEM (in comparative anatomy) shown to be in conformity with the development of the nervous system, iii. 530. non-existent in the Acrita, iii. 533. as apparent in Bryozoa, iii. 535. in Co-lelmintha, iii. 534. in Echinodermata, iii. 537. Encrinus, Comatula, iii. 537. Asterias, Echinus, iii. 537. Holothuria, Siponculus, iii. 537. in Epizoa, iii. 536. in Heterogangliata, iii. 540. Gasteropoda, iii. 540. Pteropoda, iii. 541. Cephalopoda, iii. 541. in Vertebrata, iii. 541. aural system, iii. 544. costal system, iii. 542. of diaphragm, iii. 544. generative system, iii. 544. hyoid system, iii. 542. lingual system, iii. 542 muscles of the limbs, iii. 543. in Skates and Rays, iii. 543. in Lepido-siren, iii. 543. in Siren lacertina, iii. 543. in Proteus, iii. 543. inOphidia, iii.543. in Sauria, iii. 543. muscles used in mastication, iii. 543. nasal system, iii. 544. ocular system, iii. 544. opercular system, iii. 544. tegumentary system, iii. 543. vertebral system, iii. 541. vocal system, iii. 544. analysis of the tone of the muscular system, iii. 721 M. muscles of man compared with those of the lower animals, iv. 1299. Muscular arteries, iii. 786. of orbit, i. 492. inferior, i. 492. superior, i. 492. membranous laminae of the bladder, i. 380. tissue, elements of the, i. 126. See MUSCLE. of auricles, ii. 593. of ventricles, ii. 590. Musculi papillares, ii. 581. 601. pectinati, ii. 580. Muscu/o-phrenica artery, iv. 823. A/Mfcw/o-cutaneous nerve, great, iv. 761. 769. small, iv. 761. upper, iv. 761. lower, iv. 762. origin and course, iv. 769. internal terminal branch, iv. 769. external branch, iv. 769. brachial nerve, ii. 524. Musculo.s\rir&\ artery, ii. 160. nerve, i. 217. 361 ; iv. 758. branches : internal cutaneous, iv. 759. for the internal head of the triceps, iv. 759. for the long head of the triceps, iv. 759. for the outer head of the triceps and anconaeus, iv. 759. external cutaneous, iv. 759. anterior terminal, iv. 759. external large branch, iv. 759. internal terminal branch, iv. 759. deep terminal branch, iv. 75'J. Mushrooms, mode of reproduction of, s. 232. Music, soothing effect of, ii. 565. See Sound, Musical instruments, alleged analogy between the action of the vocal ligaments and that of the reeds of, iv. 1481. Musk, i. 482. Musk-deer, the, i. 508. Musk-gland of the crocodile, iv. 325. Mussel, sea, description of the, i. 621, 622. ciliary motion in the, i. 622. in the embryo of, i. 627. nervous system of the, iii. 604. preparations of the nerves of, iii. 605. Mustard considered as food, s. 395. Mustelidce, or Weasel tribe, dentition of the, iv. 913. Mutton fat, chemical characters of, ii. 223. Mycetes, a genus of Quadrumana, iv. 210, et scq. See QlTADRUMANA. characters of the genus, iv. 210. Mycodermatous vegetations, iv. 144. Myelitis, characters of the urine in, iv. 1291. Mi/gale, nervous system of the, iii. 609. Mylodon robustus, pelvis of the, s. 162, 163. Mylo-hyo\d groove, ii. 214. muscle, iii. 105. 564. action and relations, iii. 5o-l. ridge, ii. 214. Myopia, or near sight, iv. 1462. GENERAL INDEX. 821 Myopia — continued, causes, iv. 1463. usual course of the affection, iv. 1464. treatment, iv. 14ti4, 1465. myopic spectacles, iv. 1466, 1467. Myopotarnus, or coma, anatomy of the, iv. 373, et fcq. Myoxus, or dormouse, anatomy of the, iv. 376, et seq. Myrianida fasciata, mode of reproduction of, s. 33. MYRIAPODA, a class of Articulated animals, i. 110 ; iii. 544. general description of the class, iii. 544. classification, iii. 545. anatomy and physiology, iii. 547. alimentary canal, iii. 549. biliary apparatus of, iv. 446. salivary glands of Echinodermata, iv. 431. circulatory system, iii. 549. foramina repugnatoria, iii. 550. nervous system, iii. 550. 6C9. organs of generation, iii. 551. spermatozoa of the, iv. 492. ova. iii. 553. development of the embryo, iii. 553. history of the process according to the observations of Newport on the Julus, iii. 553-^560. and of Gervais on the growth of Lithobius, iii. 560. organs and mode of locomotion of the, iii. 443. senses, iii. 550. list of Myriapoda possessing the property of luminous- ness, iii. l'J8. Myriapoda chilognatha, iii. 545. Myrmecobius, a genus of Marsupialia, iii. 260, et seq. characters of" the genus, iii. 260. fasciatus, iii. 260. Myrmecopkaga, or ant-eater, its mode of taking its prey, iii. 8. Mynneleonidte, or ant-lions, ii. 865. Myrtiform fossa, ii. 207. muscle, ii. 223. MylHus (mussel), nervous system of the, iii. 604. preparations of the, iii. 605. jfyftna glutinosa, or hag-fish, iii. 976. teeth and parasitic habits of, iii. 976. N. Neevus maternus, or mother's mark, i. 242 ; ii. 333. classification of nasvi, i. 243. speculations as to structure of, i. 243. vascular naevi of the face, ii. 228. Naidcs. organs of circulation in the, i. 650. Nails, structure of, s. 477. adventitious formation of, iv. 139. 143. of cats, i. 255. Naja, asps or hooded snakes, poison fangs of, iv. 291. Nape of the neck, or nucha, i. 367- furunculi in the, i. 368. Narcotic*, effects of, on the heart and bowels, iii. 30. on nervous system, analogous to dreaming, iv. 690. Narcs interne, or cavae nares, iii. 723. calculi of the, iv. 82. Nasal apparatus of Pachydermata, iii. 874. snout of hog, iii. 874. proboscis of elephant, iii. 875. Nasal artery, i. 492 ; iii. 786. of septum, i. 487. externa communis, i. 487. laterales nasi, i. 487. dorsales nasi, i. 487, bone, i. 729; ii. 210. 212; iii. 725. borders, ii. 212. 1. superior, ii. 212. 2. inferior, ii.212. 3. external, ii. 212. 4. internal, ii. 212. connexions, ii. 212. development, ii. 212. structure, ii. 212. surface?, ii. 212. 1. anterior, or cutaneous, ii. 212. 2. posterior, or pituitary, ii. 212. canal, iii. 725. cartilages, iii. 726. cavity, iii. 723, 724. duct, iii. 90. 92. 725. osseous duct for the, iii. 92. plica and villi, iii. 92. secretion, iii. 92. structure, iii. 92. fossa, i. 731 ; ii. 212 ; iii. 723. infundibulum, iii. 724. internal, or ethmoidal, branch of the fifth pair of nerves, iii. 733. lamella, i. 731. meatuses, i. 7 -"A. inferior, iii. 725. superior, iii. 724. muscles, ii. 222. nerve, ii. £81 ; iii. 93 785. external, ii. 282. Nasal artery — continued, anterior superior, ii. 287. posterior superior, or Vidian, ii. 287, 283. or lachrymal, process of the lowest spongy bone, iii. 91. process, or plate, i. 729; ii. 208. 210. borders, anterior, posterior, and upper, ii. 208. prominence, i. 729. Nasal septum, — septum mobile nasi, i. 731 ; iii. 725, 726. spine, posterior, ii. 210. Nasalis labii superioris rcuscle, Hi. 729. relations and actions, iii. 729. JViMo-labialis muscle, ii. 224. JVcwo-lobar nerve, ii. 282. Mwo-maxillary, or anterior border of superior maxillary bone, ii. 209. Naso-or.u\ar nerve, it 281. A'cwo-palatine ganglion, ii. 287. 371. nerve, ii. 282. or internal surface of superior maxillary bone, ii. 208. Natatores, or swimming-birds, characters of, L 269. pelves of, s. 168. Natchez Indians, remarkable custom of the, iv. 1360. Kates (of brain), iii. 677- 6S5. Nausea, sensation of, ii. 26. causes of, ii. 27. vomiting, ii. 26. NautUidte, fossil shells of the, i. 520 characters of the family, i. 520. Nautilus, i. 520, et seq. * organ of smell of the, iv. 700. renal organs of the, iv. 232. paper-nautilus, or Argonaut, mode of progression of the, iii. 436. Navicular bone, ii. 340. 343. of carpus, ii. 505. articulations, ii. 505. fossa, i. 727 : ii. 550 ; iv. 1248 ; s. 709. Near sight See Myopia ; VISION. Neat's^foot oil, chemical characters of, ii. 233. Nebulte of the cornea, ii. 177. NECK, iii. 561. definition, iii. 561. I. Muscles, iii. 561. a. anterior vertebral group, iii. 561. longuscolli, iii. 5 SI. rectus capitis anticus major, iii. 561. b. lateral vertebral group, iii. 561. intertransversales colli, iii. 561. rectus capitis lateralis, iii. 561. anticus minor, iii. 561. scalenus anticus, iii. 562. posticus, iii. 562. c. depressors of os hyoides, iii. 562. sterno-hyoid, iii. 563. sterno-thyroid. iii. 563. thyro-hyoid, iii. 563. omo-hyoid, iii. 563. digastric, iii. 563. stylo-hyoid, iii. 564. mylo-hyoid, iii. 564. d. connected with the tongue, iii. 564. hyo-glossus, iii. 564. stylo-glossus, iii. 565. genio-hyo-glossns, iii. 565. lingualis, iii. 565. genio-hyoideus, iii. 565. e. superficial on the side of the neck, iii. 565. sterno-cleido-mastoideus, iii. 565. platysma myoides, iii. 566. risorius San'torini, iii. 566. II. Fasciae, ii. 2-30; iii. 566. superficial or subcutaneous areolar tissue, iii. 566. cervical, iii. 568. pre-vertebral, iii. 569. cervico-thoracic septum, iii. 570. III. Regional or surg;cal anatomy, iii. 570. superficial veins and nerves, iii. 571. 1. mesial region of the neck, iii. 572. laryngotomy and the parts concerned, iii. 573. tracheotomy and the parts concerned, iii. 574 crico-tracheotomy, iii. 574. 2. antero-inferior triangle, iii. 574. thyroid body, iii. 575. bronchocele, iii. 575. oesophagotomy, and the parts concerned, iii. 576. 3. antero-superior triangle, iii. 576. glandulae concatenate, iii. 577. 4. postero-superior triangle, iii. 577. 5. postero-inferior triangle, iii. 577. subclavian artery, and operations connected therewith, iii. 578. subclavian vein, iii. 579. jugular vein, iii 579. thoracic duct, iii. 579. arteria innominata, and operations connected therewith, iii. 580. 6. digastric space, iii. 581. 7. posterior pharyngeal region, iii. 582. 8. relations of the >terno-cleido mastoidcus, iii. 583. 822 GENERAL INDEX. NECK — continued. Practical observations relating to the anatomy and diseases of the neck, iii. 583. 1. diagnosis of tumours, iii. 583. 2. collateral circulation after obliteration of the main arterial trunks, iii. 584. 3. anomalous arrangements of the cervical vessels, iii. 585. 4. remarks on the veins, iii. 585. congenital fissure (fistula colli congenita), iv. B53. Neck of rib, iv. 1026. of the scapula, iv. 573. Necrophaga, a sub-tribe of Coleoptera, ii. 860. Necrosis of bone, i. 453. bones liable to necrosis, i. 456. process by which it is accomplished, i. 453. the sequestrum, i 455. time necessary for the completion of necrosis, i. 455. of the cranium, i. 746. of the hyoid bone, iv. 1162. of the bones of the face, ii. 220. of the bones of the knee-joint, combined with acute arthritis genu, iii. 64. displacements occurring in chronic necrosis in the vicinity of the knee, iii. 65. Negrito race, physical and mental characters of the, iv. 1362. Negroes, characters of the, iv. 1352. distinctive characters of the crania of, iv. 1321. portrait of young Negro of Benguela, iv. 1321. characteristics of the brain of, iii. 6t>6. capacity and weight of ,. ventricles of brain, iii. 625. olfactory nerves, Hi. 625. optic lobes, iii. 625. cerebellum, iii. b25. table showing the actual and relative lengths of the cerebral hemispheres and the cerebellum in the Mammalia, iii. 626. general remarks in conclusion, iii. 626. See also under the various headings of classes, &c.f of animals. NERVOUS CENTRES (in human anatomy), iii. 626. definition, iii. 626. general and descriptive anatomy of the nervous centres, iii. 627. Coverings of the nervous centres, iii. 627. of the ganglions, iii. 627. of the spinal cord and brain, iii. 627. dura mater, iii. 627. spinal, iii. 628. cranial, iii. 628. processes, iii. 629. falx cerebri, iii. 6C9. tentorium cerebelli, iii. 629. falx cerebelli, iii. 629. vessels of the spinal dura mater, iii. 629. of the cranial dura mater, iii. 630. sinuses, 631. superior longitudinal, iii. 631. inferior longitudinal, iii. 631. strait, iii. 631. torcular Herophili, iii. 631. lateral sinuses, iii. 632. occipital, iii. 632. petrosal, superior and inferior, iii. 632. transverse, iii. 632. cavernous, iii. 633. circular, iii. 633. pia mater, iii. 633 of the spinal cord, iii. 633. of the brain, iii. 6J4. continuations of the pia mater into the cerebral ventricles, iii. 634. choroicl plexuses of the lateral ventri- cle, iii 6:>4. velum interpositum, iii. 6.55. choroid plexuses of the fourth ventri- cle, iii. 635. crystalline formations in the choroid plexuses, &c., iii. 635. connexions, &c. ot the pia mater, iii. 636. in reference to pathology, iiL 636. arachnoid, iii. 636. spinal, iii. 636. arachnoid bag or sac, iii. 636. sub-arachnoid cavity, iii. 636. internal arachnoid, hi. 637. cerebral, iii. 637. cerebro-spinal fluid, iii. 638. fluid in the cerebral ventricles, iii. 640. orifice of communication, as described by iMajendie, between the fourth ventricle and the sub-arachnoid space, iii. 640. estimate of the quantity of the sub-arach- noid fluid, iii. 641. cerebro -spinal fluid in reference to patho- logy, iii. 642. manner of its secretion, ii:. 643. physical and chemical properties of the cerebro-spinal fluid, analyses, iii. 643. use of the cerebro-spinal fluid, iii. 643. glamlultc Pacchioni, iii. 644. are they natural structures ? iii. 645. ligamentum dentatum, iii. 64-5. General remarks on the structure of nervous centres, i. 646. white nervous matter, iii. 646. NERVOUS CENTRES — continued. grey nervous matter, iii. 647. development, iii. 648. remarks on the great simplicity of form of the elements of grey nervous matter, iii. 649. pigment, ii. 649. Structure of ganglions, iii. 649. Cerebro-spinal centre, iii. 650. Spinal cord, iii. 650. position, iii. 651. shape, iii. 651. bulk, iii. 651. length and circumference, iii. 65L fissures, iii. 652. anterior, iii. 652. posterior, iii. 652. white commissure, iii. 652. grey commissure, iii. 652. internal structure as shown by transverse sec- tions, iii. 653. antero-lateral columns, iii. 653, 654. posterior columns, iii. 653, 654. arrangement of the grey matter in the spinal cord, iii. 653. ' conclusions, iii. 654. is there a central canal in the spinal cord ? iii. 655. blood-vessels, iii. 656. anterior spinal artery, iii. 656. posterior spinal arteries, iii. 657. veins, iii. 657. spinal nerves, origin, anterior and posterior roots, ganglion, iii. 657. sub-occipital nerve, iii. 658. characters proper to the nerves of particu- lar regions, iii. 658. cervical nerves, iii. 658. dorsal nerves, iii. 658. lumbar nerves, cauda equina, iii. 658. relations of the roots of the nerves to the columns of the cord and to the grey matter, as determined by dissection, iii. 659- as determined by physiology, iii. 660. Encephalon, iii. 661. size compared with that of the body in diffe- rent animals, iii. 661. compared with that of the encephalic nerves, iii. 662. weight of the human encephalon, iii. 662. table showing the average absolute weight of the human encephalon, in males and females, iii. 662. relative weight of encephalon to cere- bellum, &c. in males and females, iii. 663. relative weight of entire body to ence- phalon, cerebrum, cerebellum, &c. iii. 663. conclusions, iii. 664. absolute weight of the brain of the elephant and whale, iii. 664. weight of brain of some animals greater than that of man, relatively to the weight of their bodies, iii. 664. conclusions of Tiedeman, deduced from his observations, iii. 664. remarks on the comparison of the brain of man with that of the lower animals, iii. 664. the brain in different races of mankind, iii. 665. method of examining the brain, iii. 667. method of Willis, iii. 668. of Reil, Gall, and Spurzheim, iii. 669. surface of the encephalon, iii. 670. shape of the brain, iii. 670. superior and lateral surfaces, iii. 670. base of the brain, iii. f>70. anterior segment, olfactory sulcus, iii. 670. fissure of Sylvius, locus pcrforatus anticus, island of Reil, iii. 671, 672. middle segment, iii. 672. pituitary process, tuber cinereum, iii. 673. optic Iracts and optic commissure, iii. 673. corpora albicantia, iii. 673. crura cerebri, intercrural space, substantia perforata, pons Ta- rini, iii. 673. transverse or horizontal fissure, iii. 673. circle of Willis, iii. 673. posterior segment, iii. 673. dissection of the brain from above down- wards, iii 674. centrum ovale minus and majus, iii. 674. corpus callosum, longitudinal tracts, iii. 674. 824- GENERAL INDEX. NERVOUS CENTRES, dissection of brain — continued. lateral ventricles, iii. 67*. septum lucidum, iii. 674. fifth ventricle, iii. 674. parts seen in the lateral ventricles, iii. 675. fornix, iii. 675. third ventricle, iii. 676 pineal gland, iii. t,"7. anterior commissure, iii. 675. soft commissure, iii. 6/7. mesocephale, iii. 677. corpora quadrigemina, iii. 677. processus cerebelli ad testes, iii. 677. valve of Vieusseii!!, iii. 678. pons Varolii, iii. 678. cerebellum, iii. 678. fourth ventricle, iii. 678. examination of the various segments of the ence- phalon, with a more especial reference to the structure and physiological bearing of each, iii. 678. medulla oblongata, iii. 678. columns, anterior pyramidal, iii. 679. 684. olivary, iii. 679. 683, 684. corpus dentatum, iii. 6,'3. posterior pyramidal, iii. 679. 683. course of fibres, iii. 660. restiform, iii. 679. 682. 684. interpretation of the various columns, iii. 684. definition, iii. 679. development, iii. 683. fibres of, antero-posterio-, iii. 680. 685. arciform, iii. 680. decussating, iii. 680. nerves connected with, iii. 684. shape, iii. 697. transverse sections of, iii. 683. mesocephale, iii 684. pons Varolii, iii. 685. corpora quadrigemina, iii. 685. processus cerebelli ad testes, iii. 686. valve of Vieussens, iii. 686. conclusions, iii. 686. cerebellum, iii. 687. arbor vitae, lateral and median, iii. 692. castration, alleged effects of, on the cere- bellum, iii. 687. commissures, iii. 691. long and hidden, iii. 691. short and exposed, iii. 691. single, iii. 691. corpus dentatum or rhomboideum, iii. 692. crus cerebelli, iii. 692 peduncles of, iii. 693. inferior, iii. 693. middle, iii. 693. superior, processus cerebelli ad testes, or cerebro-cerebellar com- missures, iii. 693. development of the cerebellum, iii. 687. relative development of cerebellum to cere- brum in the adult, iii. 687. fissures, iii. 687. horizontal, iii. 688. purse-like fissure, or posterior notch, iii. 688. semilunar, iii. 687. valley, iii. 687. lamina?, iii. 689 — 691. lobes and lobules, iii. 689. amygdala, iii. 689. 692. biventral, iii. 689. 692. median, iii. 689. posterior, iii. 689. 692. pyramid of Reil, iii. 691. uses, iii. 691. posterior superior lobe, iii. 689. 692. slender, iii. 689. spigot of Reil, iii. 691, 692. uses, iii. 691. square lobe, iii. 689. 691. nodule, iii. 690. 693. shape ot the cerebellum, iii. 687. sections of the cerebellum, iii. 692. horizontal, iii. 692. vertical, iii. 692. size and weight of the cerebellum, iii. 687. subdivisions into median lobe and lateral lobes or hemispheres, iii. 687. surfaces, inferior, iii. 689.691. superior, iii. 689. 691. tentorium cerebelli, iii. 687. velum, posterior medullary, iii. 6SO. ventricle, fourth, iii. 693. aqueductus Sylvii, iii. 693. calamus scriptorius, iii. 693. choroid plexuses of the fourth ven- tricle, iii. 693. NERVOUS CENTRES, cerebellum — continued. vermiform process, iii. 687. inferior, iii. 687. superior, iii. 687. white and grey matter, iii. 692. microscopic anatomy of the cerebellum, iii. 709. hemispheres of the brain, iii. 678. 693. definition, iii. 6y3. 695. convolutions, iii. 6P3. indie, it ons afforded by the existence of convolutions, iii. 694. absence of convolutions in all the classes below Mammalia, iii. 694. Gall and Spurzheim's views of, iii. 695. primary convolutions in the fox, iii. 696. in the dog, iii. 696. in cats and hyenas, iii. 696. secondary convolutions in ruminants, iii. 696. in the elephant, iii. 696. in the monkey, iii. 696. in the human subject compared with that of the inferior animals, iii. 696. symmetry, iii. 696. constant convolutions in the hu- man brain, iii. 6D7. 1. the internal convolution, iii. 697. 2. convolution of the Sylvian fissure, iii. 698. 3. insula of Reil, iii. 698. 4. pair of convolutions en- closing the olfactory pro- cess, iii. 698. hippocampi, iii. 698. direction of the white fibres in the con- volutions, iii. 693. disappearance of the convolutions in hydrocephalus, iii. 698. corpora striata, iii. 698. course of fibres, iii. 699. vesicular matter, iii. 699. optic thalami, iii. 700. corpora geniculata, iii. 700. corpora mammillaria, iii. 701. commissures of the brain, iii. 701. longitudinal commissures, iii. 701. 1. superior longitudinal commis- sure, iii. 701. 2. longitudinal tracts, iii. 701. 3. fornix, iii. 701. 4. taenia semicircularis, iii. 702. transverse, iii, 702. 1. corpus callosum, iii. 702. 2. anterior commissure, iii. 702. 3. posterior commissure, iii. '/03. 4. soft commissure, iii. 703. tuber cinereum, iii. 703. pituitary body, iii. 703. ventricles of the brain, iii. 704. circulation in the brain, iii. 704 arterial, iii. 704. venous, iii. 705. question as to whether the amount of blood within the cranium is liable to variation, iii. 706. encephalic nerves, iii. 707. Sketch of the microscopic anatomy of the spinal cord and brain, iii. 707. of spinal cord, iii. 707. medulla oblongata, iii. 708. mesocephale, iii. 709. cerebrum and cerebellum, iii. 709. Brief statement of the probable modus operand! of the brain, iii. 710. NERVES AND NERVOUS CENTRES (abnormal anatomy), iii. regeneration of nervous matter, iii. 712. abnormal anatomy of the spinal cord and its membranes, iii. 712. membranes, iii. 712. affections of the dura mater, iii. 713. See SPINE. of the arachnoid, iii. 713. of the pia mater, iii. 713. cord, iii. 713. absence of the cord, iii. 713. partial deficiencies, iii. 714. excessive congenital development, iii. 714. hypertrophy, iii. 714. atrophy, iii. 714. induration, iii. 714. softening, iii. 714. red softening, iii. 714. white softening, iii. 714. suppuration, iii. 715. effusion of blood, iii. 715. tubercle, iii. 715. cancer, iii. 715. GENERAL INDEX. 825 NEHVE3 AXD NEIUOfS CEXTRTS — Continued. Abnormal anatomy of the brain and its membranes, Hi. Membranes, iii. 715. dura mater, iii. 715. general or partial deficiency, iii. 715. acute disease, iii. 715. causes, iii. 715. treatment, iii. 715. adhesion to the cranium, 715. patches of bone in the processes of the dura mater, iii. 715. fibrous tumours, iii. 715. cancer, iii. 715. fungus of the dura mater, iii. 716. effusion of blood, iii. 71b". arachnoid, iii. 716. acute inflammation, iii. 716. opaque condition of, iii. 716 causes of opacity, iii. 716. adhesion, iii. 716.. de[>osits of bone or cartilage, iii 716. effusions into the subarachnoid and arach- noid cavities, iii. 716. of serum, iii. 7 16. of blood, iil 717. of pus, iii. 717. pia mater, iii. 717. injected state of the vessels, iii. 717. tubercle, iii. 717. Brain, iii. 718. congenital abnormal conditions, 718. absence of the brain, iii. 718. brain of idiot, iii. 718. fusion of the hemispheres, iii.71P. absence of the transverse commissures, iii. 719. acquired or morbid conditions, iii. 719. hypertrophy, iii. 719. cases recorded, iii. 720. parts of the brain affected, iii. 720. atrophy, iii 720. softening, iii. 720 A. white, iii. 720 A. red. iii. 720 B. suppuration, iii. 720 B. hypera>mia, iii. 720 C. active and passive, iii. 720 C. causes, iii. 720 C. anaemia, iii. 720 C. cerebral haemorrhage, 720 D- cancer, iii. 720 E. tubercle, iii. 720 E. entozoa, iii. 720 E. morbid states of the ventricles, iii. 720 E. thickened and opaque condition of the lining membrane, 720 F. choroid plexus, deposit of lymph on, iii. 720 F. earthy concretions in, iii. 720 F. vesicles in— formerly regarded as hydatids, iii. 720 F. pseudo-morbid appearances of the nervous centres and their coverings, iii. 720 F. abnormal anatomy of nerves, iii. 720G. absence of, iii. 720 G. inflammation, iii. 720 G. atrophy, iii. 720 G. hypertrophy, iii. 720 G. tumours, iii. 720 G. syncope by nervous lesions, death from. i. 794. regeneration <>f voluntary nerves, iv. 141. fatty accumulation in the, iv. ^6. NERTOIS SYSTEM (physiology of the}, iii. 7?OG. vital endowments of nerves and of nervous centres, iii. 720 G. nervous polarity, iii. 720 II. sensitive and motor, incident and reflex nerves, iii. 720 H. the stimuli of nerves iii. 720 K. mental stimuli, iii. 720 K. physical stimuii, iii. 720 K. effects of the galvanic stimulus, iii. 720 L. of the conditions necessary for the maintenance of the power of developing nervous force, iii. 720 O. nervous influence or energy, i. 722. vis nervosa, iii. 29. vis insitain connexion with vis nervosa, iii. 30. new laws of action of the vis nervosa, iii. 30. Des Cartes' vague theory of the chief source of nervous power, iii. 677. of the nature of the nervous force, iii. 720 P. is the nervous force electricity y iii. 7?0 Q. conclusions respecting muscular and nervous forces, iii. 7% 8. of the functions of nerves, iii. 720 T. of the roots of spinal nerves, iii. 720 U. of the nervous centres, 720 X. of the spinal cord, *20 X. facts in the physiological history of the spinal cord, iii. 7-'o'X. physical nervous actions of the cord, iii. 721 A. Supp. NERvot's SYSTEM — continued. sympathetic actions, iii. 721 A. \Vhytt's views, iii. 721 B. summary of Prochaska's work, iii. 721 C. facts which demonstrate a power in the cord of exciting movements in parts which re- ceive nerves from it by changes occurring in its substance, iii. 721 G. stimulus applied to the cord, iii. 721 G. substances exerting a peculiar influence upon the spinal cord, iii. 7-'l G. strychnine, iii. 721 G. opium, iii. 721 H. cold, iii. 721 H. ether, iii. 721 H. sensitive impressions may be reflected by the cord, iii. 7*1 H. enumeration of the functions of the body with xvhich the spinal cord is immediately concerned, iii. 721 L Dr. Marshall Hall's doctrine regarding, iii. 721 1. tone of the muscular system, iii. 721 M. conclusions, iii. 721 N. of the office of the columns of the cord, iii. 721 N. antero-lateral columns, iii. 721 O. posterior columns, iii. 721 O. manner in which the posterior co- lumns may contribute to the exer- cise of the locomotive functions, iii. 721 Q. middle or respiratory column of Sir C. Bell, iii. 721 R. influence of the spinal cord upon the organic functions, iii. 721 R. on the kidneys, iii. 721 S. erection of the penis, iii. 721 T. mechanism of the functions of the cord, iii. 721 T. Dr. Marshall Hall's hypothesis of an ex- cito-motory system c-f nerves and true spinal cord, iii. 721 U. hypothesis of Miiller and others that every nerve-fibre in the body is continued into the brain, iii. 722 B. Todd and Bowman's hypothesis that all the nerves are implanted in the grey matter of the segments with which they are connected, and do not pass beyond, iii. 722 B. functions of the encephalon, iii. 722 I. of the medulla oblongata, iii. 722 I. corpora striata, iii. 722 L,. locus niger, iii. 722 M. optic thalami, iii. 722 M. corpora quadrigemina, iii. 722 O. olivary bodies, and flocks of Reil, iii. 722 O. mesocephale, iii. 722 P. emotion, iii. 722 P. diseases associated with disturbed state of emotion, iii. 722 O. may be regarded as the centre of emotional ac- tions, iii. 722 Q. of the cerebellum, iii. 722 Q. coordination of movements, iii. 722 R. Gall's views, connexion of the cerebellum with the sexual functions, iii. 722 S. of the cerebral convolutions, 722 X. Dr. Wigan's doctrine of the duality of the mind, iii. 722 Z. sensation, iii. 723 A. volition and attention, iii. 723 A. sleep, iii. 723 B. dreaming, iii. 723 B. coma, iii. 723 B. somnambulism, iii. 723 B. delirium, iii. 723 B. fibres of thecentrum ovale, iii. 723 B. of the commissures, iii. 7^3 B. corpus callosum, iii. 723 D. fornix, iii. 723 D. pens Varolii, iii. 723 E. summary of the physiology of the enccpha'on, iii. 723 F. physiology of the ganglions, iii. 723 F. functions of the ganglions, 723 F. Nerves in particular : — abdominal, large, iv. 761. small, iv. 761. nbducentes oculi, iii. 707. accessory, i. 7-3!. acoustic. See auditory, acromial, iv. 753. branches, iv. 753. for adductor magnus, iv. 765. anastomotic branches of acromial, iv. ~5l. of ankle, i. 151. of anus, i. 181. arterial, i. 224. articular, iv. 768. auditory, ii. 27 2. 530. 539; iii. 597. 692. 707. 3 H 826 GENERAL INDEX. Nerves in particular — continued. auricular, great, iii. 903 ; iv. 753. superficial branch, iv. 753. deep branch, iv. 753. external, ii. 294. 555. internal, ii. '293. 555. posterior, iv. 546. branch of temporal, iii. 903. of vagus, iii. 883. 890 901. auriculo-teinporal, iii. 903. axillary, iv. 759. to biceps, iv. 756. 767. of bones, i. 436. for brachialis anticus, iv. 756. buc-cal, ii. 291 ; iii. 950 ; iv. 547. of bulb of penis, iii. 918. calcaneal, superior and inferior, iv. 770. internal, iv. 770. cardiac, inferior or small, ii. 595. 851 ; iii. 575. 887 ; ir. 815 ; s. 425. left, ii. 595. middle, ii.595, left, ii. 596. superior, or long, ii. 595 ; iii. 722. cardiac branch of vagus, iii. 887. 896. 902. of ninth pair, iii. 722. carotid of glosso-pharyngeal, ii. 496, of Vidian, ii. 288. cerebro-spinal, s. 443. cervical, i. 748; ii. 272; iv. 754. descending, iii. 721. internal, iii. 721 ; iv. 753. superior, ii. 272. posterior roots, ii. 272. See SPINAL NRRVES. cervico. facial, iii. 904. chorda tympani, ii. 549. ciliary, ii. 282. branches, ii. 282. fasciculi, ii. 282. circumflex, i. 3(il ; iv. 436. 606. 757. clavicular, iv. 753. of clitoris, s. 709. for cochlea, ii. 5.34. 540. communicans fibula;, iv. 768. tibialis, iv. fi2. noni, iv. 753. communicating of acromial, iv. 753. to coraco-brachialis, iv. 756. ofCotunnius, ii.287. of cranium, i. 748,749. for cruraeus, iv. 763. crural anterior, iv. 761. femoral, iv. 762. cutaneous, external, i. 217- 361 ; ii. 61 ; iv. 756. internal, i. 217. 361 ; ii. 64 ; iv. 755. 763. malar, ii. 284. middle, iv. 763. long, ii. 252. of arm, internal, ii. 561. of Wrisberg, iv. 756. palmar, iv. 757- peroneal, iv. 768. of shouhier, iv. 760. perforating, inferior, iv. 763. superior, iv. 763. tibial, iv. 764. deep, of Vidian, s. 426. deltoid, iv. 760. dental, anterior superior, ii. 289. inferior, ii. 292. 294. posterior superior, ii. 289. desccndens noni, iii. 721 ; iv. 754. of diaphragm, ii. 4; iv. 754. digastric, iii. 904; iv.547. of glosso-pharyngeal, ii. 496 ; iii. 949. digital, first, iv. 757- second, iv. 757. third, iv. 757. fourth, iv. 757. filth, iv. 757. terminal, iv. 757. dorsal of penis, iii. 918 ; iv. 766. (thoracic) posterior, iv. 751. first, anterior, iv. 758. internal, iv. 758. of ear, ii. 756. encephalic, iii. 707. of face, ii. 2-23, 229. See FIFTH PAIR OF NERVES ; SEVENTH PAIR OF CEREBRAL NERVES. facial, ii. 228, 2!>9. 540. 544. 554, 555 ; iii. 707. 949. See FIFTH PAIR OF NERVES; SEVENTH PAIR OF CERE- BRAL NERVES. of l-'ailopian tube, s. 603. femoral, iv. 762 to femoral vessels, iv. 763. fifth, i. 288. lingual branch, iv. 1141. of foie-arm. ii. 361. fourth, ii. 370; Hi. 784. frontal, ii. 279 ; iii. 95. 784. internal, i. 748. Nerves in particular — continued. ganglionic, iii. 547. gastric of vagus, i i. 899. for gemelli muscles, iv. 767. genicular, internal, ii. 241. genito-crural, ii. 838 ; iv. 761, 762. branch, iv. 762. glosso-pharyngeal, i. 732 ; ii. 494 ; iii. 707. 882. 949. gluteal, superior, iv. 766. inferior, iv. 766. to gracilis muscle, iv. 764. gustatory, ii. 292 ; iii. 721 ; iv. 1141. haemorrhoidal, inferior, iv. 766. hypo-gastric, iii. 918. hypo-glossal, iii. 707. 721 ; iv. 1141. ilio-hypogastric, iv. 761. ilio-scrotal, iv. 761. infra-clavicular, iv. 755. infra-maxillary, iv. 548. infra-orbital, ii. 284. infra-trochlear, ii. 282; iii. 93. inguinal, external, iv. 762. inguino-cutaneous, small, iv. 762. intercostal, iv. 760. great, s. 423. branches, iv. 760. second, i. 217. third, i. 217. costo-humeral, i. 360. intercosto-humeral, iv. 760. interosseous, iv. 757- 768. of musculo-spiral, iv. 759. of Jacobson, ii. 495. 55*. of kidney, iv. 2,16. labial, inferior external, ii. 294 ; iii. 950. internal, ii. 295 ; iii. 950. labyrinthic of olfactory, iii. 733. lachrymal, ii. 282; iii. 93. 784. laryngeal, iii. 112.886. 893- 895. 901. inferior, or recurrent, iii. 113 ; iv. 1107. superior, iii. 112. functions of the laryngeal nerves, iii. 113. lenticular, ii. 281. lingual of fifth, ii. 292. 295 ; iii. 949; iv. 820. 1141. of glosso-pharyngeal, ii. 497. of liver, iii. 174. for long head of the biceps, iv. 767. lumbar, anterior, iv. 761. posterior, iv. 752. lumbo-sacral, iv. 761. of lymphatic glands, iii. 218. malar, ii. 284. branch of optic, iii. 788. cutaneous, ii. 284. malleolar, iv. 769. of mammae, iii. 249; iv. 753. masseteric, ii. 291. masticatory, ii. 271. mastoid, anterior, iv. 753. external occipital, iv. 753. maxillary, superior, i. 749; ii. 283; iii. 787. inferior, i. 749 ; ii. 291, 292. 294. origin and course, ii. 290, i;91. median, i. 361 ; iv. 756. inarm, i. 217.361: ii. 524. in hand, ii. 527. muscular branches, iv. 756. anterior interosseous nerve, iv. 756. palmar cutaneous branch, iv. 757. terminal digital branches of the median, iv. 757. of medulla oblongata, iii. 684. to tnembrana tympani secundaria, ii. 519. molles, i. 224. motor linguae, i. 732; iii. 723. motores oculorum, iii. 707. of mucous system, iii. 493. of muscles, iii. 516. musculo-cutaneous, brachial, ii. 524. great, iv. 761. of leg, i. 151. lower, iv. 762. small, iv. 761. upper, iv. 761. musculo-spiral, i. 217. 361 ; iv. 7-58, 759. nasal, ii 281 ; iii. 93. 731. 785. anterior superior, ii. 287. external, ii. 282. posterior superior, ii. 287. naso-ocular, ii. 281. naso-lobar, ii. 282. nervorum, iii. 595. ninth, iv. 721. 1141. obturator, iv. 761. 76t. 766. accessory, iv. 764. deep, iv. 765. long cutaneous, iv. 765. superficial, iv- 764. oasophageal, ii. 3 ; iii. 759. 89.3. P01. olfactory, iii. 625. 707. 731 ; iv, 6(J8. to omo-hyoid, iii. 721, 722. ophthalmic, ii. 279 ; iii 93; iv. 621. branches, ii. 1.79— 282. GENERAL INDEX. S27 Nerves in particular — continued. optic, iii. 595, 596. 676. 707. 762. 785. origin and course, iii. 762. orbicular, iv. 547. orbitar, i. 749. orbital of superior maxillary, iii. 787. palatine, ii. *86 ; iii. 951. great, ii. 286. lesser, ii. 286. middle, ii. 286. posterior, ii. 287. palmar cutaneous of median, ii. 524. palpebral, ii. 280. 289. external, ii. 289. internal inferior, ii. 289. of pancreas, s. 86. par ragum, ii. 595 ; iv. 546. 815, 816. pathetic, ii. 570; iii. 707. distribution, ii. 370. function, ii. 370, 371. origin and cranial course, ii. 370. to pectineus, iv. 763. of penis, iii. 9J7, 918. perineal, external, iv. 439. internal, iv. 439. cutaneous, iv. 767. superficial, iii. 918 ; iv. 766. peroneal, iii. 132 ; iv. 62. 768. branches, iv. 768. petrosus superficialis s. major, ii. 554 ; iv. 545. minor, Arnoldi, ii. 555. tertius. ii. 555, note. petrous branch of VSdian, ii. 288. pharyngeal of glosso-pharyngeal, ii. 496. branch of vagus, iii. 885. 892. 901. phrenic, ii. 3. 4 ; iv. 754. 815,816. left, iv. 75*. right, iv. 754 . plantar, internal, iv. 770. external, iv. 771. branches, it. 770, 771. pneumogastric. i. 732; ii. 3.554; iii. 112.572. 692. 70". 759. 949 ; s. 262. popliteal, external, iv. 62, 768, 769. internal, iv. 62. portio dura, i. 748, 749 ; iii. 93. 572. 707. 903 ; iv. 545. 548. branches, iii. 904. portio mollis, ii. 272. 530. 539 ; iii. 597. 692. 707. pterygoid, external, ii. 292. internal, ii. £92. pudendal, inferior, iv. 439 ; a. 714. pudic, iii. 928; iv. 1254; s. 714. internal, iii. 918; iv. 766. pulmonary branches of vagus, iii. 896. 898. 902. for pyriformis, iv. 767. for q'uadratus femoris, iv. 767. radial, i. 217 ; ii. 64. 160 ; iv. 759. recurrent of ophthalmic, ii. 279 ; iii. 113. of pneumogastric, iii. 759; s. 262. branch of vagus, iii. 867, 888. 895. 901. renal, h for rhombokieus, iv. 755. respiratory internal, iv. 754. sacral, iv. 752 765. saphenus, i. 148 ; ii. 352. accessory, iv. 7<>3. external", or communicans tibiali.*, iii. 130: iv. 770. internal, iii. ISO. satellite of femoral artery, iv. 763. sciatic, iv. 459. lesser, iv. 766. greater, iv. 7o7. for semi-membrano^us, iv. 768. for semi-tendino-us, iv. 767. septual of olfactory, iii. 7.32. to serratus magnus, iv. 755. seventh pair, iv. 543. sixth pair, iii. 787 ; iv. 621. spermat.c, external, iv. ~u-2. spheno-maxillary, ii. 283. spheno-palatine, ii. 284. spinal, s. 641. posterior branches, i. 368. accessory, i. 731, 732; iii. 707- 885. 890; iv. 745. 751. 820. splanchnic, left, ii. 4 ; s. 641. right, ii. 4. lesser, ii. 4. of the spleen, iv. 794. sternal, iv. 753 to sterno-hyoid, iii. 722. 732. stylo-hyoid, iii 904 ; iv. £-47. for subclavius, iv. 755. subcutaneous of the hand, ii. 524. suboccipital, iii. 658. 707; iv. 750. subscapular, inferior, i. 361 ; iv. 75! superior, i. 361. superficial of neck, iii. 571. temporal, i. 749 ; ii. 284. 293. supra-acromial twigs, iv. 571. Nerves in particular — continued. supra-clavicular, iv. 753. 755. 818. supra-maxillary, iv. 548. supra-orbicular, iv. 547. supra-orbital, i. 748. of supra-renal capsules, iv. 833. supra-scapular, iv. 434. 755. supra-trocheator, L 748. supra-trochlear, ii. 280 ; iii. 93. branches, ii. 280. sympathetic, i. 423; iii. 598, 599. 949 ; iv. 621. 816; s. 262. ofVidian, ii. 288. of taste, iv. 858. temporal facial, ii. 283. 555 ; iii. 904. superficial, i. 749; ii. 1-84. 293; iii. 903 : iv. 547. deep. i. 749; ii.291. branch of optic, iii. 787. temporo-malar, ii. 284. branches, ii. 284. of testicle, iv. 982. third nerve, iii. 785. inferior division, Hi. 787. thoracic, i. 361. anterior, or short, i. 361 ; iv. 755. middle, i. 361. posterior, or respiratory, i. 361. of thymus gland, iv. 1%4. to thyro-hyoid, iii. 722. of thyroid gland, ir. 1107. tibial, anterior, i. 151 ; iii. 132. 134 : iv. 62. 768, 769. posterior, i. 150. of tongue, iv. 1141. tonsillitic twigs of glosso-pharyngeal, ii. 497. of trachea, s. 262. trifacial, ii. 268. See FIFTH PAIR OF NERVES. trigeminal, ii. 268. trisplanchnic of Chaussier, s. 423. tympanic of Jacobson, ii. 495. 554, 555. ulnar, i. 217. 361 ; ii. 64. 527, 528 ; iv. 757. branches, iv. 758. of ureters, s. 466. of urethra, iv. 1254. 1259. 1265. of urinary bladder, L 587. of uterus, s. 641. vaginal, s. 707. vascular branch of vagus, iii. 887. for vastus intermix, iv. 763. 1381. vestibular of auditory, ii. MO. Vidian, ii. 287. of Wrisberg, i. SfiO. Nerve -tubes. See NERVE. JNVroe-vesicles, caudate, iii. 647. Nervous tissue, element of the, i. 126. Netts of birds. See AVES ; INSTINCT Neumatoneura, locomotion of the, iii. 534. Neuralgia, il 229 ; iiL 720 K. of the urethra, iv. 1263. Neurilema, ii. 185. of nerves, iii. 591. wavy course of the nerve-tubes within the, iii. 593. Neurine, iii. 593. Neuruma, or tumours formed upon nerves, iii. 720 G ; iv. ML Neuropfera, an order of Insecta, ii. £64. characters, ii. 864. divisions, ii.864. wings of, iii. 421. mode of flight of, iii. 421. New Forest, infested with forest-flies (Hippobosca cquina>' in summer, ii. 8o7. \etrtont Sir Isaac, his experiment on the effect of the light of the sun upon the retina, iv. 1445. Newt, water, respiratory organs of the, s. 278. 283. respiratory movements of, iv. 1020. ova of, s. 51. fight-mare iv. 683. \ight-moths (Nocturna), ii. 867. \tiotic nations, mental and physical characters of the, iv. 1356. XIMH P.UR o? NERVES, iii. 684. 721 ; iv. 1141. origin and course, iii. 7^1. branches, iii. 721. of communication with the superior cervical gan- glion, iii 721. de.-cendens noni, iii. 721. omo-hyoid branch, iiL 721. plexus, iii. 722. sterno-hyoid and thyroid branches, iii. 722. cardiac branch, iii. 722. thyro-hyoid branch, iii. 722. anastomoses with branches of the fifth, iii. 722. ultimate distribution, Hi. 722. comparative anatomy, iii. 722. root of the ninth nerve in the ox, iii. 722. in birds, iii. 723. in fishes, iii. 7£3. physiology of the ninth nerve, iii. 723. 'ipples, or mammilla?, iii. 246. cuticle, rete mucosum, and cutis of nipple, iii. 246. 3 H 2 828 GENERAL INDEX. Nipples — continued. form and position, iii. 246. alterations in form during lactation, iii. 245. glands and papillae, iii. 246. the areola, ii. 247. change in colour after impregnation, iii. 247. cuticle and cutis of the areola, iii. 247. tubercles of the areola, iii. 247. Nirmidte, or bird-lice, ii. 868. N/sus formations of Blumenbach, theory of, iii. 145. Nitric acid, action of, on protein, iv. 164. on fibrin, iv. 166. Nitrogen, analysis of a solid not containing nitrogen, iii. 814. of a liquid not containing nitrogen, iii. 816. of a body containing nitrogen, iii. 817. nitrogen thrown off by decaying bodies, iv. 45J. Nltrolcucid acid, iv. 165. Az/ro-saccharic acid, ii. 405. te, physical characteristics of the existing descendants of the, iv. 1336. Nochthora, a genus of Quadrumana, iv. 211, et scq. See QUADRUMANA. characters of the genus, iv. 211. Nocturna, or night-moths, a section of Insects of the class Lepidoptera, ii. 867. characters of the .section, ii. 867. Nodes described, i. 449. distinguishable from exostosis, i. 460. of cranium, i. 749. of the tibia, iii. 136. of the joints of the head, ii. 518. Nodule, the, iii. 690. 693. NOSE, iii. 723. bones, iii. 723. structure of, iii. 726. cartilages, iii. 7<6. structure of, iii 727. muscles, iii. 54 1. 727. pyramidalis, iii. 728. levator labii superioris alzcque nasi, iii. 728. triangular!*, iii. 728. depressor alaa nasi, iii. 728. depressor septi narium, iii. 729. muscular fasciculi which dilate and compress the nostrils, iii. 729. rhomboideus, iii. 729. purposes served bv the muscles of the nose, iij. 729. integuments, iii. 729. skin, iii. 7^9. mucous membrane, iii. 730. epithelium, iii. 730. course, iii. 731. nerves, iii. 731. olfactory, iii. 731. roots, iii. 731. tractus olfactorius, trunk, iii. 732. bulb, iii. 732. branches, iii. 732. septual, iii. 732. labyrimhic, iii. 733. other nerves, iii. 733. See FIFTH PAIR OF NERVES; SEVENTH PAIR OF NEUVES. vessels, iii. 733. mucus of the, iii. 481. analysis of, iii. 482. chemical characters of, iii. 482. development of the nose, iii. 73t. physiology of the nose, iii. 735. See also FACE; LA- RYNX; Mucus; SMELL. NOSE (morbid anatomy), iii. 736. congenital defects, iii. 736. diseases, iii. 738. of the skin, iii. 738. red nose, iii. 738. tuberculated induration and thickening, iii. 738. of the nasal cavities, iii. 738. colds, iii. 738. simple abscesses, iii. 738. thickening of the mucous membrane, iii. 738. ulceration, iii. 739. polypi, iii. 739. vesicular, iii. 740. gelatinous, iii. 740. fibrous, iii. 740. malignant, iii. 740. enlarged appearance of, in hard drinkers, ii. 228. nasal calculi, iv. 82. Nostrils, iii. 726. cartilages of the, iii. 726. Notch of acetabulum, ii. 776. cotyloid, s. 116. ligament of the, iv. 434. of palate bone, ii. 211. posterior, or purse-like fissure of the cerebellum, iii. 688. sacral, s. 119. sacro-sciatic, s. 12". sciatic, great, s. 11"). small, or obturator, s. 115. sigmoid, ii. 214. Notch — continued. sub-pubic, s. 127. ventral, s. 126. Noteus, a genus of loricated Rotifers, iv. 408. Notommata, a genus of Rotifera, iv. 404. longiseta, iv. 410. myrmeleo, iv. 413. Nourishment of the young, instincts guiding parents in procuring, iii. 15. Nubians, mental and physical characters of the, iv. 1356. Nucha, or napj of the neck, i. 367. furunculi in the, i. 363. ligament of, of Pachydermata, iii. 876. Nuchiis, ligament of, i. 732. Nuck, canal of, iii. 943 ; s. 706. Nuclei of intestinal calculi, iv. 84. animal, vegetable, and inorganic, iv. 8k Nudn, characters of the family, i. 523. Nudibranchiata, ii. 377. See GASTEROPODA. " Nurse " and " grand-nurse " of Steenstrup, s. 31. 37. See GENERATION; OVUM. NUTRITION, i. 130 ; iii. 741. definition, iii. 741. object of nutrition, iii. 741. materials required for nutrition, iii. 742. type of the process in cellular plants, iii. 742. elaboration of organisable materials, iii. 742. reduction of every protein compound to albumen, iii. 742. change from albumen to fibrin, iii. 743. formation of tissue, iii. 747. homogeneous membrane and fibres formed from fibrin independent of cells, iii. 748. development of tissues that originate in cells, iii. 750. influence of the spinal cord on the function of nutrition, iii 721 S. affinity between the functions of nutrition and secre- tion, iv. 440. nutritive regeneration, iv. 677. See SLEEP. animal and vegetable nutrition compared, i. 130. varying activity of the nutritive process, iii. 75J. hypertrophy. Hi. 751. atrophy, iii. 752. abnormal forms of the nutritive process, iii. 753. inflammation, iii. 753. suppuration, iii. 754. tubercle, iii. 754. parasitic growths, iii. 755. non-malignant, iii. 755. malignant, iii. 756. arrest of the fluid of nutrition a cause of death, i. 792. depravation of the fluid of, a cause of death, i. 792. changes in the nutritive secretion arising from injured nerves, iv. 468, 469. general summary, iii. 756. Nutritive substances, animal and vegetable, ii. 13. See Food; DIGESTION; STOMACH. Nymph form of insects, ii. 879. Nymfihte, s. 710. structure of, s. 710. erectile tissue of the, ii. 446. uses of, s. 710. size of the, in early foetal life, ii. 686. abnormal anatomy of the nymphs, s. 710. O. Oak trees, injuries to, by the Scolytus pygmaeus, ii. 862. Oat-meal, effect of abundant use of, in producing intestinal calculi, iv. 84. Obesity, pathological conditions of the adipose tissue, i. 61. See ADIPOSE TISSUE. Obliquitas uteri, s. 683. Obliquus ascendens muscle, i. 6. descendens, i. 5. abdominis externus, i. 5; s. 137. internus, i. 6; ii. 840 ; s. 137. superior muscle of the eye, iii. 785. inferior, iii. 787. action of the oblique muscles, iii. 78P. capitis inferior, or major, muscle, i. 373. superior, or minor, i. 373. 732. Obliteration of the aorta, i. 191. Obturator fascia, i. 177. 388. pelvic, s. 138. Obturator muscle, externus, s. 137. internus. iv. 766; s. 137. nerve, ii. 779 ; iv. 761. 764. accessory obturator, iv. 764. superficial branch, iv. 764. long cutaneous branch, iv. 765. deep branch, iv. 765. or small sciatic, notch, s. 115. or sub-pub c, groove, s. 116. artery, ii. 250. 779. 843. 831. origin and distribution, ii. 831, 832. or thyroid, foramen, s. 116. incirbrane, s. 124. 126. ossification of the, s. 207. vein, iv. 1412. GENERAL INDEX. Ocean, effect of animal life at the bottom of the ocean on the economy of the world, iv. 38. absolute darkness of the, at the depth of 800 to 1000 feet, iii. 204. Oceanic nations, mental and physical characteristics of the, iv. 136}. variety in the complexion of the, iv. 1334. Ocelli, or simple eyes, of Insects, ii. 961. in Arachnidans, i 207. Occipital artery, i. 367. 487. 748 ; ii. 542. 556. bone, i. 731. anterior angle, i. 731, 732. connexion, i. 733. development, i. 731. lateral angles, i. 732. superior angle, i. 732. basilar process of the, i. 726. muscle, i. 747, 748. nerve, great, iv. 751. protuberance, internal, i. 732. ridge, inferior, i. 732. superior, i. 732. sinuses, iii. 6~29. sulcus, i. 732. 734. tubercle, external, i. 732. vein, iv. 1405, 1406. ventricle, iii. 674. Occipito-frontal region, i. 746. See CRANIUM, regions and muscles of. muscle, i. 732. 747. 749. Occiput, \. 725. Oclopoda, i. 520. divisions of the tribe, i. 521. parasitic nature of the, i. 54i, 545. Octopus vulgaris, its mode of creeping on the shore, iii. MS. eyelids of the, iii. 95. Ocular conjunctiva, iii. 83. See Conjunctiva. peduncles of Crustacea, i 758. Oc«A>-cerebral congestion, a cause of myopia, iv. 1464. Ocythoe, genus of Testacea, i. 523. Odontoid ligament, i. 732. Odontoliths, or tartar, of teeth, iv. 83. Odorous emanations, hypotheses of the nature of, iv. 697, rsa (Ecistes, a gfnus of Rotifera, iv. 4C2. CEcistina, a family of Rotifera, iv. 401, et seq. characters of the family, iv. 401. genera of, iv. 402. (Edema, i.516; iii. 82. 85. (Egosceiidte, a sub-order of Mammalian quadrupeds, 8. 508. anatomical characters of, s. 508, et seq. CStopAageal arteries, i. 193; s. 326. branches of ncrvus vagus, iii. 895. 901. nerves, ii. 3. plexus, left, iii. 889. right, iii. 889. (EaoPBAQlS, i. 11 ; iii. 758 ; iv. 816, 817. definition, iii. 758. normal anatomy, iii. 758. dimensions, iii. 758. directions, iii. 7;",8. mucous membrane, iii. 759. cesophageal glands, iii. 75'J. relations, iii. 758. cervical, iii. 758. thoracic, iii. 758. abdominal, iii. 758. structure, iii. 758. vessels and nerves, iii. 759. ce.sophageal branches of the nervus vagus, iii. 895. motor influence of the sympathetic in refer- ence to the oesophagus, s. 46 K function of the oesophagus, iiL 759. uses of, in digestion, ii. 8. abnormal anatomy, iii. 760. congenital malformation, iii. 760. acquired malformation, iii. 760. structural changes, iii. 761. stricture, iii. 761. morbid growths, iii. 761. calculi of the, iv. 83. surgical anatomy of the oesophagus, iii. 576. cesophagolomy, iii. 576. oesophagus of fishes, iii. 981. of Kuminantia, s. 5-i5. (Estrid<£, or gad-flies, ii. 867. (Estrus, ii. 127. Offence .and defence, instincts designed for the purposes of, iii. 7. Oil, nutritive properties of, ii. 13. Oil-beetles (Cantharidae), ii. 863. Old age. See AGE. Operation process, i. 217; ii. 63. 66. 162. surfaces, ii. 162. structure, ii. 163. fractures, ii. 169. Oleophosphoric acid, iii. 587. Olfactory apparatus, in infancy, i. 73. in old age, i. 80. Olfactory nerve, or olfactory lobe of the brain, iii. 625. 707. 731 ; iv. 698. posterior, or pyramid, iii. 731. anterior, or bulb, iii. 731. middle, or proper trunk, iii. 731. roots, iii. 625. 731. tractus olfactorius, trunk, iii. 732. bulb, iii. 732. branches, iii. 732 septual, iii. 732. labyrinthic, iii. 733. peripheral expansion of the, iii. 697. process, or lobe, iii. 597. 698. 722 N. convolutions which enclose the fissure of the, iii. oa sulcus, iii. 668. See also NOSE ; SMELL. Olivary bodies, ii. 270 ; iii. 679. 683. 684. 722 O. corpus dentatum of, iii. 683, 684. process, i. 728. tracts, or fasciculi innominati of Cruveilhier, iii. 678, 679. Omasum, psalterium, manyplies or feuillet (third stomach), of Kuminantia, ii. 11 ; s. 537. Oiiiciitum, i. 57. greater, or gastro-colic, i. 502; iii. 937, 938. 941. 8. 309. sac of the, iii 938. layers of, iii. 941. vessels and nerves of, iii. 942. use of, iii. 942. horology of, iii. 942. lesser, iii. 941. layers of, iii. 941. vessels of, iii. 941. use of, iii. 941. splenic, iii. 941. ligaments of, iii. 941. use of, iii. 941. gastro-splenic, iv. 771 ; s. 309. gastro-hepatic, or small, s. 309. phreno-gastric, s. 309. hernia of, ii. 763. See HERNIA. condition of the omentum in cases of umbilical hernia, ii. 763. Omichmyle, iv. 1270. Owo-clavicular space, iv. 817. 0/wo-hyoid muscle, i. 483 ; iii. 105. 563. action and relations, iii. 563. branch of ninth pair of nerves, iii. 721. Owz/>Aa/o-enteritic duct, s. 401. 0/»/>Aa/0-mesenteric artery, i. 169. Onagga, or Dauw (Equus montanus), the, iv. 714. Ondatra, anatomy of the, iv. 370, et seq. Onyx or hypopion, ii. 203. Opacity and transparency of bodies, iv. 1433. Opalina, digestive organs of, 8. 295, Ophidia, an order of Kept ilia, iv. 265. 272, et seq. ciliary motion in, i. 631. digestive organs of, s. 301. teeth of, iv. 888. tongue of, iv. 1147.' organs and mode of progression of the, iir. 445. organs of respiration of, s. 281. muscular system of, iii. 543. pancreas of Ophidia, s. 95. thymus gland of, iv. 1098. vocal organs and voice of, iv. 1502. Ophiuri, muscles of the, iii. 537. Ophrydinidce (Ipricated bell animalcules), a family of Poly- gastric animalcules, iv. 4. characters of the family, iv. 4. Ophryocercinidte (swan animalcules), a family of Polygastric animals, iv. 5. characters of the family, iv. 5. Ophthalmia, catarrhal, causes of, iii. 86. 94. Egyptian, causes of, iii. 86. Ophthalmic artery, i. 491 ; ii. 179. 186. 227 ; iii. 93. 733.785. branches, i. 491, 402. 730. nerve, ii. 279 ; iii. 93 ; iv. 621. branches, ii. 279—282. See FIFTH PAIK OF NERVES. ganglion, ii. 281. pustula, ii. 176. tentacles of Cephalopoda, i. 526. See CEPHALOPODA. vein, ii. 228; iii. 786. cerebral, iii. 94. facial, iii. 94. Opiothrvc fragilis. ovum of, s. [126.] Opisthotunos, i. 719. Opium, effect of large doses of, on the action of the heart, i. 797. its peculiar influence upon the spinal cord, iii. 721 H. O*»f fiXfteu, or laserpitium, iv. 862. Opossums, iii. 261, et seq. habits, peculiarities, &c. of, iii. 261. pelvis of, s. 160. organs of voice of the, iv. 1491. Flying, or Petaurists, iii. 263, et seq. pigmy, iii. 257- Virginian, iii. 257. 3 ii 3 830 GENERAL INDEX. Opponens minimi digiti muscle, ii. 521. relations and uses, ii. 521. pollicis, s. flexor ossis metacarpi muscle, ii. 519. relations and uses, ii. 520. OPTIC NERVES, ii. 185, 18fi; iii. 7U7. 762. 783. descriptive anatomy, iii. 762. apparent origin, iii. 762. tnictus opticus, iii. 76*2. chiasma, iii. 7r>2. optic nerve proper, iii. 762. first stage, iii. 7(52. second stage, iii. 762. communication with other nerves, iii. 763. organisation, iii. 763. real origin, iii. 763. evidence derived from comparative anatjmy, iii. 76*. Fish, iii. 764- Keptiles, iii. 7t>4. Birds, iii. 764. in Man the optic nerves derive some roots from the tubercula quadrigemina, iii. 765. the tubeicula quadrigemina probably fulfil other purposes besides that of affording origin to the optic nerves, iii. 766. the human optic nerve probably derives roots from the optic thalamus, iii. 766. corpora geniculata : their relation to the optic nerves, iii. 763. tuber cSnereum : its relation to the optic nerves, iii. 768. commissure of, iii, 595. 676 ; iv. 1446. peripheral expansion of the, iii. 596. of the chiasma of the optic nerves, iii. 768. in Invertebrata, iii.76a. Osseous Fish, iii. 769. Cartilaginous Fish, iii. 769. Birds, iii. 7r9. Amphibia and Reptiles, iii. 769. Mammalia and Man, iii. 7G9. use of the chiasma, iii. 771. some remarkable varieties of optic nerves, iii. 774. optic nerves in certain Ophalopods, iii. 774. optic nerves of the compound eyes of Insects, iii. plaited optic nerves, iii. 776. optic nerves in cydops monsters, iii. 777. general development of the optic nerves in the higher classes of nnimaU, iii. 77". Fish, iii. 777. Birds, iii 777. Mammalia, iii. 777. functions of the optic nerves, iii. 778. the optic nerves when present are essential to vision, iii. 7/8. in tho.se animals which possess special optic nerves the fifth pair are totally inadequate to support vision, iii. 778. absence of proof th;it the fifth pair is absolutely essential to sight, iii. 778. ordinary tactile sensibility, iii. 780. effects of stimulants, iii. 780. excito-motory properties, iii. 781. radiated or sympathetic sensations, iii. 782. Optic pore of optic nerve, iii. 186. 192. thalami, iii. 675. 700. corpus geniculatum externum, iii. 700. internum, iii. 700. fibres, iii. 700. commissures, iii. 700. sections, iii. 701. structure, iii. 700. functions of the optic thalami, iii. 722 M. the optic thalami the centre of sensation, iii. 722 M, 723 B. tracts, iii. 673. 762. Opticnl principles governing the construction of micro- scopes, iii. 331. See MICROSCOPE. Optoidal surfaces, iv. 1440. Optameter of Dr. Porterfield,i v. 1441. Orbicular, or annular, ligament, iv. 229. nerves, iv. 547. Oi'bicularis palpehrarnm muscle, iii. 80, 81. 211. 221 tendon of the, iii. 81. action, ii. 221. relations, ii. 221. uses of the, iii. 82. See also FACE. or sphincter oris muscle, it. 223. relations, ii. 223. actions, ii. 224. Orbiculus s. circulus ciliaris,— ciliary circle of choroid coat, ii. 180. ORBIT, iii. 782. bones, iii. 782. angles, iii 7^-3. superior and external, iii. 783. superior and internal, iii. 783. inferior and external, iii. 783. inferior and internal, iii. 783. base or circumference, iii. 783. ORBIT — continued. dissection of the orbit, iii. 783. periosteum, iii. 183. lachrymal gland, iii. 784. fourth nerve, iii. 784. frontal nerve, iii. 784. lachrymal nerve, iii. 784. muscles, iii. 784. levator palpebrae superioris, iii. 784. rectus superior, iii. 784. obliquus superior, iii. 785. third nerve, iii. 785. nasal nerve, iii. 785. lenticular ganglion, iii. 785. optic nerve, iii. 785. ophthalmic artery, iii. 785. lachrymal artery, iii. 786. central artery of the retina, iii. 786. supra-orbital artery, iii. 786. ciliary arteries, iii. 786. muscular branches, iii. 786. ethmoidal arteries, iii. 786. palpebral arteries, iii. 786. nasal arteries, iii. 786, frontal arteries, iii. 786. ophthalmic vein, iii. 786. sixth nerve, iii. 787. inferior division of the third nerve, iii. 7S7. recti muscles, external, inferior, and internal, iii. 787. inferior oblique muscle, iii. 787. orbital portion of the superior maxillary nerve, iii. 787. temporal branch, iii. 787. malar branch, iii. 788. " tunica vaginalis " of Mr. O'Ferrall, iii. 788. action of the muscles of the orbit, iii. 788. of the levator palpebrje, iii. 788. recti, iii. 788. obliqui, iii. 789. consensual movements of the two eyes, iii. 791. adaptation of the eye to distances, iii. 792. See also VISION. Orbital foramina, i. 730, 731. nerve, i. 749 ; iii. 787. process, i. 730, 731 ; ii. 211. or external, surface of lachrymal bone, ii. 212. or superior, surface of malar bone, ii. 211. or anterior superior, border of malar bone, ii. 211". surface of the superior maxillary bone, ii. 208. borders, ii. 208. Orirto-palpebral muscle, ii. 222. Orchis morio, mode of origin and early development of the embryo in, s. 250. Orchitis, iv. 1004. acute, iv. 1004. chronic, iv. 1006. syphilitic, iv. 1008. ORGANIC ANALYSIS, iii. 792. I. Proximate analysis, iii. 793. manipulation, iii. 793. reagents, &c., iii. 793. desiccation, iii. 793. incineration, iii. 794. filtration, iii. 795. decantation, iii. 795. A. Analysis of animal fluids, iii. 795. 1. for the organic constituents, iii. 795. qualitative analysis, iii. 795. fibrin, iii. 795. albumen, iii. 795. fatty matters and cholesterin, iii. 796 sugar, iii. 796. urea, iii. 796. uric acid and the urates, iii. 7C6. quantitative.analysis, iii. 79o. process, iii. 796. special consideration of the different animal principles, iii. 797. fibrin, iii. 797. fatty matters, serolin and butyrin, iii. 798. albumen, iii. 798. casein, iii. 798. urea, iii. 799. sugar, iii. 799. uric acid, iii. 800. urobenzoic or hippuric acid, iii. 800. lactic acid, iii. 8(;(). oxalic acid, iii. 800. 2. for the inorganic constituents, iii. 801. qualitative analysis, iii. 801. quantitative analysis, iii. 802. carbonic, phosphoric, and hydrochloric acid, iii. 802. sulphuric and phosphoric, iii. 503. iouine, fluorine, and sulphur, iii. 803. bases, iii. 803. potash, soda, ammonia, iii. 804. iron, lime, magnesia, lead, iii. 804. copper, in. 8U5. GENERAL INDEX. 831 ORGANIC ANALYSIS, Proximate — continued. B. Analysis of animal solids, ill. 805. cholesterin, iii. 805. uric acid and urates, iii. 805. cystic oxyde, iiL 805. albumen and fibrin, iii. 805. gelatinous tissues, iii. 806. hairs, iii. 806. earthy phosphates, iii. 806. carbonate of lime, iii. 806. oxalateof lime, iiL 806. C. Analysis of individual secretions, iii. 807. 1. of the urine, iii. 807. healthy urine, iii. 807. diabetic urine, iii. 808. albuminous, iii. 809. 2. of the blood, iii. 809. the serum, iii. 810. the clot, iii. 810. 3. of milk, iiL 811. 4. of bile, iii. 811. 5. of saliva, iii. 812. II. Ultimate analysis, iii. 813. analysis of a solid not containing nitrogen, iii. of a liquid not containing nitrogen, iii. 816. of a body containing nitrogen, iii. 817. method of determining the equivalent number of an organic substance, iiL 819. Organic life, i. 263. Organic matter, 'considered, iii. 152. presumed impossibility of artificially producing organic compounds or proximate principles, considered, iii. artificial and natural conversion of gum, starch, and lignin into sugar, iii. 153. catalytic action, iiL 153.. evolution of electricity during the ordinary processes of growth of plants and animals, iii. J54. inability of chemists to produce organic compounds probably due to their want of acquaintance with the form or condition in which their components must be brought together, in order to enter into the desired union, iii. 154. conclus ons deduced from the foregoing paragraphs, iii. 154. See also LIKE. actions common to both organic and inorganic matter, iii. 150. reasons for believing that organic and inorganic compounds have a similar constitution, iii. 152. Organisation and stimulus, conditions required for the pro- tiuction of vital actions, iii. 142. vital properties due to the act of organisation, iii. 142. connexion of organisation with vitality, iii. 148. See LIFE. Organised bodies compared with unorganised, i. 118. See ANIMAL. Ornitliurtiynchus paradoxus, the, iii. 367, et seq. description of the animal, iii. 3rt7. mammary glands of the, iii. 251. mode of generation of the, ii. 437. structure of the ovum of the, s. [91.3 pelvis of the, s. 161. organs of voice of the, iv. 1492. See MONOTREMATA. Orthoptera, an order of Insecta, ii. 864. characters of the order, ii. 834, nervous system of the, iii. 610. Orycteropus, or Cape Ant-eater, teeth of the, iv. 870. Orycterus, white-spotted (Bathiergus capensis), iv. 389. Oryctes nasic&rnis, nervous system of, iiL 610. Osculu of sponges, iv. 67. Onsa maxillaria superiora, ii. 207. palatina, ii. 2iO. spongiosa, v. turbinata infima, ii, 212. triquetra, triangularia, suturarum, supranumcraria, i. 744. "Wormiana, i. 744. Osseous deposits in the diaphragm, ii. 6. in old age, i. 81. in the valves of the heart, ii.647. Osseous fishes. See PISCES " Osseous jmce," ancient theory of, in the adhesion of bones, i. 414, 445. Osseous labyrinth, ii. 533. liquid contained in the, ii. 536. membrane lining the, ii. 533. Osseous system, i. 438. See also BONK. diseases of the, i. 4>9. in early life— growth, i. 438. nativity, i. 43-i. old age, i. 439. OSSEOUS SYSTEM (comparative anatomy\ iii. 820. general remarks, iii. 822. enumeration of the parts of a perfect vertebrate endo- skeleton, iii. 823. skeleton of the Crocodile, iii. 823. spinal column, iii. 8.3. elements of a vertebra, iii. 824. autogenous parts, r, exogenous parts, iii. 824. OSSEOUS SYSTEM— continued. skull, iii. 825. occipital vertebra, iiL 827. parietal vertebra, iii. 827. frontal vertebra, iii. 827. bones of the cranium, iii. 828. frontals, iiL 828. anterior frontals, posterior frontals, iii. 829. parietals, iii. 829. external occipitals, lateral occipitals, inferior occipital or basilar. iiL 829. sphenoid, alars, iii. 829. squamo-temporal, pet ro- temporal, iii. 829. ingrassial bones, iii. 829. ethmoid, vomer, nasal bones, iii. 830. inferior turbinated, iii. 830. maxillary, intermaxillary, iii. 830. suborbital, prenasal, supra-temporal, iii. 831. palatine bones, transverse bones, internal pterygoid, zygomatic, masto-temporal, iii. styloid, symplectic, iii. 833. lower jaw, iii. 833. opercular, angular, articular, iii. 833. hyo-branchial apparatus, iii. 833. hyoid, iiL 8Jd branchiostegous rays, iii. 834. branchial arches, iii. 834. pharyngeal bones, iii. 834. condition of the os hyoides in Reptiles, iii. 835. metamorphosis of the os hyoides, iii. 835. thorax, iii. 806. vertebral ribs, iii. 836. sternum, iii. 837. sternal ribs, iii. 838 limbs, iii. 839. anterior, iii. 839. scapula, iii. 839. clavicle, iii. 839. coracoid, iii. 840. humerus, id. 840. fore-arm, iii. 840. carpus, iii JS40 metacarpus, iii. 841. phalanges, iii. 841. posterior, iii. 842. ilium, iiL 842. ischium, iii. 842. pubis, iii. 842. marsupial bones, iii. 84?. femur, iii. 843. tibia, iii. 84& fibula, iii. 843- tarsus, iii. 843. metatarsus, iii. 843. phalanges, iii. 844. sesamoid bones, iii. 844. exo-skeleton, iii. 844. suborbital bones, &c., iii. 845. opercular bones, iii. S45. supra-temporal, iii. 845. bones of the ?zygos fins of Fish, iii. 845. OSSEOUS TISSUE, i. 127; iii. 847. general description, 847 hyalitic substance, iii. 847. laminae, iii. 849. Haversian canals, iii. 849. corpuscles or cells, iii. 850. growth of bone, iii. 853. madder experiments, iii. 853. development of osseous tissue, iii. 854. ossification of permanent cartilage, iii. 857- abnormal osseous plates in the soil tissues, 857. formation of osseous tissues in the union of fractures, iii. 857. Ossicles or small bones of the ear, iL £46. See HEARING, , ORGAN OF. office of the, in the functions of hearing, ii. 573. 577. Ossification, abnormal, iv. 134. See Osteoma. of cartilages of the larynx, iii 121. of the serous membranes, iv. 537. of the ovary, s. 574. of the valves of heart, ii. 647. of the gal I- bladder, iii. 18d Osteitis, or inflammation of bones, i. 443. See BONES, PA- THOLOGICAL CONDITIONS OF. of the bones of the knee-joint, combined with acute arthritis genu, iii. 64. of hip-joint, strumous, ii. 789. case of, ii. 789. strumous, of the metacarpal bones and phalanges of the fingers, ii. 516. Osteoid or ossifying tumour, iv. 135. Osteoma, or abnormal ossification, iv. 134. in the natural tissues, iv. 1. 4. healing of fractured cartilage, iv. 134. osteophytes, iv. 134. osteoma, iv. 135. osteoid, or ossifying fungous tumour, iv. 135. bone formation iu the interior of new products, iv. 135. Osfeomalacia, iv. 97., 3 H 4 832 GENERAL INDEX. OsteopJiytes, iv. 134, 135. Csteoptcrygii, a division of Fishes, iii. 956. characters of the division, iii. 956. Osteosarcoma, ostecsteatoma, spinaventosa, enchondroma, i. 460; iv. 132-134. description of, i. 460. localities attacked, i. 460. progress of, i. 462. symptoms, i. 462 of the bones of the face, ii. 220. malignant, of the hand, ii. 516. benign, of the hand, ii. 514—516. remarkable case of, ii 515. 0A-teo-sarcomatous tumours of the pelvis, s. 206. Osteum sinus, ii. 538. internum aqueductus vestibuli, ii. 530. sive apertura, scalar vestibuli cochlete, ii. 530. tubuli, ii.538. Ostfiim abdominale, s. 599, 600. uterinum, s. 599. recti. See ANUS. Ostrea (oyster), nervous system of the, iii. 604. Ostrich, pelvis of the, s. 167. velocity of the, iii. 451. Otic, or auricular, ganglion of Arnold, ii. 292. 555. See SYMPATHETIC NERVE Otitls of the membrana tympani, ii. 575. Oto Indian, portrait of, iv. 1363. Oloconia, ii. 539. See HEARING, ORGAN OF — membraneous labyrinth. office of the, in the function of hearing, ii. 567. Otoglena, a genus of Rotifera, iv. 404. Otolicnu , a genus of Quadrumana, iv. 214, et seq. See QUADRUMANA. characters of the genus, iv. 214. Otulitki, ii. 539. See HEARING, ORGAN OF — membraneous labyrinth, office of the, in the function of hearing, ii. 567. of fishes, iii. 1004. Otter, feet and mode of progression of the, in water, iii. 43. classified arrangement of all the condition* which the Graafian follicle exhibits during evolution and involution, s. 570. summary of the cone Hsions which the>e conditions afford with reference to questions in obstetric and forensic medicine, s. 571. development and involution of the ovary, s. 571- the origin of the ovary, and the alterations which it undergoes at different periods of life, s. 571. Ovary — continued. abnormal anatomy of the cvary, s 573. effects of extirpating the ovary, s. 573. deficiency and arrest of development, s. 573. atrophy and hypertrophy, s. 573. softening of the, iv. 712. induration of the, iv. 712. displacement, hernia, s. 573. diseases of the tunics, s. 574. inflammation, s. 574. ulceration, rupture, s. 574. hypertrophy, calcification, s 574. diseases of the proper tissues, s. 576. hyperasmia, s. 576. inflammation, s. 576. suppuration, s. 577. simple, multiple, multilocular, and proliferous cysts, s. 578. the contents of ovarian cysts, s. 582. fluid contents of cyits, s. 582. quantity and rate of effusion, s. 582. composition of the fluids contained in ovarian cysts, s. 583. hydatids, s. 584. solid contents of ovarian cysts ; sebaceous and sudoriparous glands ; fat ; hair ; teeth ; true bone, s. 584. origin of the solid contents of cysts, s. 58(1 fcetus contained in the ovary (?) ; the question of ovarian gestation considered, s. 586. examples of supposed ovarHtn gestation, s. 587. origin of ovarian cysts in general, s. 590. solid enlargements of the ovary, s. 5;)1. cartilaginous and os.sific formations, s. 591. cancer, colloid or alveolar, medullary and scirrhous, s. 591 . scrofulous tubercles, s. 593. Ovicapsule. See Graafian follicle. Oviduct, s. 597. See Fallopian tube. Oviposition in Arachnidans, i. 211. See ARACHNIDANS ; OVUM. Ovls, anatomical characters of, s. 508, et seq. Ovis Ammon, vocal organs and voice of, iv. 1494. Ovisac, structure of the, s. 551. Ovo-viviparous animals, i 146. generation, ii. 424. 407. 434. See GENERATION ; GE- NKRATION, ORGANS OF. Ovology. See OVUM. Ovulathn, s. 3. See OVUM. Ovulum, or unimpregnated ovum, ii. 451. OVUM (in animal anatomy and physiology), s. 1. See also GENERATION. definition, s. 1. review of the topics to be discussed, s. 1. sexual and non-sexual modes of reproduction, s. 2. I. of the ovum in general as related to the sexual pro- cess of generation, s. 3. definition, s. 3. ovulation, s. 3. the chorion, ii. 453: s. 3. the spermatic substance or sperm, s. 3. the embryo-cell, s. 4. development, or embryo-genesis, s. 4. structural distinctive characters of an ovum, ii. 434-. 448. 451 ; s. 5. II. of the non-sexual mode of generation, s. 5. 1. of the process of reproduction in Protozoa, or animals in which the sexual distinction has not yet been discovered, s. 6. Gregarmae, s. 7. 2. of the possibility of primary, direct, or non-pa- rental production of animals, or of so- called spontaneous and equivocal genera- tion, s. 9 Entozoa, s. 11. 3. production of dissimilar individuals among the sexual animals by a non-sexual pro- cess: so-called alternate generations, s. 12. embryological development, s. 12. metamorphoses, s. 12. metagenesis, s. 13. 38. larva, s. 13. alternate reproduction of — Echinodermata, s. 14. Polypina, s. 16. Acaleph.TB, s. 20. Mollusca, s. 22. Salpidae, s. 23. Entozoa, s. 24. cystic Entozoa, s. 25. free tapeworms, s. 27. Trematoda, s. 29. Annelida, s. 32. Insecta : Aphides, s. S3. general remarks on alternate generations, s. 13. 34. the " nurse " of Steenstrup, s. 37. parthenogenesis, s. "7. additional remarks, 4". GENERAL INDEX. 833 Ovi'M — continued. of the ovum previous to the commencement of total development, s. 43. anatomical structure, chemical compoiition, origin, and formation of the ovum in man and animals, s. 43. $ 1. preliminary and general comparison of the ova of animals, s. 43. general facts ascertained in regard to the ova of animals, s. 45. division of the ova into groups, s. 46. first group, s. 46. second group, s. 46. third group , s. 47- \ 2. further comparison of the ova of animals in general, as respects their size, num- ber, form, and the relation of their parts, s. 48. size of ova, s. 48. number of ova, s. 49. external form and relation of the parts, s.50. in Birds, a. 53. in oviparous Scaly Reptiles, s.50. in oviparous Cartilaginous Fishes, s. 50. in the Frog, s. 51. in Newts, s. 51 . $ 3. of the ovary in general as the forma- tive organ for the ova, s. 52.547. a. relations of the form of the ovaries to the discharge of ova, s 54. 4. structure of the ovaries themselves, as related to the production of the ovula, s. 56. \ 4. more detailed description of the ovum of Birds, as the type of theflrst group, B 60. quantity of matter, composition, &c., s. 60. structure of the external parts of the egg, s.63. the chalazae (grandines), 64. formation of the external or accessory parts of the bird's egg, s. 65. ovarian ovum of Birds ; ovuium ; yolk and its contents, s. 63. microscopic structure of the ovum, s. 71. yellow or external yolk substance, s. 71. substance of the cavity and canal, s. 72. cicatricula, or germinal disc, and cumulus, s. 73. vitelline membrane, s. 73. [94]. [96]. early condition and first formation of the ovarian ovum in birds, s. 74. morphology of the bird's egg, as ascertained from its first origin and development, s. 75. $ 5. more detailed description of ova be- longing to the second group, or with snial! granular yolk and complete seg- mentation,*. SO. ovum of Mammalia and of the human species, s. [81]. uniformity in size, &c., s. [81]. Graafian follicles, s. [81J. tunica or membrana granulosa, s. [82]. external tunic, or zona pellucida, s. [62]. chorion, ii. 453; s. [84]. contents of the ovum, or parts within the zona, s. [86]. the yolk-mass, s. [86]. the germinal vesicle, s. [87]. the macula or nucleus, s. [87 ]• e ova of Mam malia manner in which th may be procured, s. [88 J. origin and formation of the mammiferous ovum, s. [b9]. formation of the ovules, s. [89]. origin of the Graafian follicles, s. [89]. formation of the cumulus, s. [90]. similarity of the structure of the ovum throughout the families of the class Mammalia, s. [K>]- except in the Monotremata, s. [90]. ova of the Ornithorhyncus, s. [91]. ova of Echidna hystrix, s, [91]. third group of the ova of Vertebrate Animals, «. [ 91]. Amphibia — Batrachia, s. [91]. structure of the ripe ovarian ovum in Amphibia, s. T92] embryonic development, s, [93]. yolk substance, s. [93]. germinal vesicle, s. [93]. vitelline membrane, s. [(J4]. formation of the ovum and changes in its progress, s. [91]- OVUM, Vertebrate Animals — continued Osseous Fishes, s. [98]. structure of ovarian ovum, s. [! 8]. yolk-substance, s. [99]. germinal vesicle s. [&y]. membranes, s. [V9]. micropyle, s. [101]— [103]. development, s. [I03J, [104]. Invertebrate Animals, s. [104]. large-yoked ova with partial cleavage, 8. [105]. Cephalopoda, s. [105]. Gasteropoda, s. [lOti] Acephala, s.[10a].] Arthropoda, s. [110]. Insecta, a. [110]. Arachnida, s. [114]. Crustacea, s. [115 '. Annulata, a. [117]. Rotifera, s. [118]. Turbellaria, s. [119]. Entoroa, s. [120.] Nematoidea, s, [120] Trematoda, s. C124J.- Cestoidea, s. [124]. Echinodermata, s. [125]. Polypina, s. [126]. Acalephae, s. [l«9j. Protozoa, s.[12M], Porifera, s. [129]. Recapitulation and conclusion, s. [130]. 1. definition of the ovum, as related to its own structure, and its history in connexion with the reproduction of the species, s. [130]. 2. recapitulation of the most general facts ascer- tained by the comparison of the ova of dif- ferent animals, s. [132]. 3. morphology of the ovum : homology of its parts, and relation of the ovum to other organic structures, s. [134]. 4. phenomena attendant on the maturation of the ovum, and its discharge from the ovary. iL 453 ; s. [136]. time at which it arrives in the uterus, ii. 453. irregularities in the descent of the, into the uterus, ii. 455. changes which the ovum undergoes in the Fallopian tube, s. b'09. functions of Fallopian tube, reception and transmission of ova by the Fallopian tube, s. 605. 5. relation of the ovum to fecundation by the male sperm, s. [136]. 6. immediate effects of fecundation on the ovum : segmentation, and first changes of the ovum related to the commencement of embryonic de- velopment, s. [138]. difference between the fecundated and unfecun- dated ovum, ii. 462. phenomena of fecundation, ii. 457 — 467. is material contact of the semen and ovum necessary for fecundation ? ii. 462. nature of the fecundating principle — hypo- thesis of an aura, &c., ii 466. chemical composition of the ova of animals, s. [141]. the albumen or white, s. [141]. vitelline, s. [141]. ichthine, s. [141J. ichthiciine, s. [141]-1 ichthuline, s. [141]. cohesion of germs, cases of, ii. 317. dormant vitality of eggs, iii. 156. periods of emission of ova of human females, s. 553. spontaneity of the emission of ova, s. 567. congenital malformations of the, iv. 946. mola botry oides, or hydatica, — hydrometra aquatica, iv. 946. theory of the fusion of ova in cases of monstrosity, iv. 972—976. intus-susception of one germ within another, cases of, ii. 317 ova subventanea, ii. 455. Owls, eyelids of, iii. 97. Of, anatomical characters of the, s. 508, et scq. cranium of, s. 509. 513. muscles of the, s. 524, 525. effect of castration on the growth of the horn?, ii. 718. pelvis of the, s. 157, 158. root of the ninth nerve in the, iii. 722. urine of the, iv. 1280. variation in the breeds of, under various circumstances, iv. 1311. Ox-gall, analysis of, i. 574, 375. uses of, i. 376. Oxalate of lime calculus, iv. 78. in morbid concretions, analysis of, iii. 806. deposit of, in urine in disease, iv. 1'283. Oxalic acid. iii. 800. method of determining the presence of, iii. 800. syncope from, i. 797. Oxides in animals and vegetables, i. 1C5. 834- GENERAL INDEX, Oxygen, respiration of, in animals, i. 133. 257, 258. quantity of, abstracted from the atmosphere by respi- ration, iv. 326, 327. 354. weight of oxygen gas in the atmosphere upon every part of the" earth's surface, iv. 327. OxytrichinidtE (hackle animalcules), a family of Polygastric animals, iv. 5. characters of the family, iv. 5. Oxyuri,ii. 113. Oysters, nervous system of, iii. 604. See CONCHIKUKA. Oztena, iii. 739. Paca (Cavia Paca), anatomy of the, iv. 372, ct seq. Pacchioniun bodies, iii. 629. 631. 691. description of them, iii. 644. are they natural structures ? iii. 645. glands, i. 729. 735; iii, 629. 631. 614. 645. fossae, i. 729. 735. PACHYDERMATA, an order of Mammalia, iii. 858. enumeration of genera, iii. b59. osseous system, iii. 859. cranium, iii. 859. occipital bone, iii. 859. parietal bones, iii. 860. frontal bones, iii. 8&0. ethmoid, iii. 860. sphenoid, iii. 861. ribs and sternum, iii. 861. anterior extremities, iii. 862. scapula, iii. 862. clavicle, iii. 862. humerus, iii. 862. radius and ulna, iii. 362. carpus, iii. 863. metacarpus, iii. 163. phalanges, iii. 863. posterior extremities, iii. 864. pelvis, iii. 864. lemur, iii. 864. tarsus, iii. 864. metatarsus, iii. 864. phalanges, iii. 864. teeth, iii. 865. of SuidiE, iii. 865. Choiropotamidae, iii. 865. Hippopotamidae, iii. 866. Toxodon, Elasmothenuin, iii. 8G6. Rhinocerotidse, iii. 866. Dinotherium, iii. 867. Proboscidia, Elephant, iii. 867. digestive system, iii. 871 ; s. 303. stomach and intestines, liver, iii. 871, 872. spleen, iii. 871. salivary glands, iii. 872. os hyoides, iii. 872. circulatory and respiratory system, iii. 872. thymus gland, iv. 1097. urinary organs, iii. 873. generative organs, iii. 873. male, iii. 673. female, iii. 8/3. pelvis, s. 155. Weberian organ of, iv. 1419. nervous system, iii. 874. brain, iii. 874. special senses, iii. 874. touch, iii. 874. snout, iii. 874. proboscis of the elephant, iii. 875. smell, iii. 875. frontal, maxillary, and sphenoidal si- nuses, iii. 875-6. eye, iii. 876. ligamentum nuchae, iii. 876. organs and mode of locomotion, iii. 454. PACINIAN Horn us, iii. 876 ; s. 504. general description, in. 876. stalk, iii. 878. channel for the stalk, iii. 878. capsules, iii. »78. ariery, iii. 878. central cavity, iii. 878. nerve tube, iii. 879. function, or use, iii. 879. comparison with the electrical organs of the torpedo, iii. 879 Ptepha!>omys, anatomy of the, iv. 376, et seq. Pagurus (hermit-crab;, nervous system ot tne, iii. 613. Palceotherium, anatomy of the. See PACHVDEKMATA. Palate, hard, iii. 950. See Palatine arch. soft, iii. 952. See Palatine arch. abnormal state of the, connexion between paraly- sis of the portio dura and, iv. 553. Palate bones, ii. 210. borders, ii. 210. anterior, ii. 210. infi-rior, ii. 211. interior, ii. 210. superior, ii. 211. Palate — continued. connexions, ii. 211. development, ii. 211. structure, ii. 211. Palatine arch, and gums, iii. 950. gums, iii. 951. velum, palati, iii. 951. muscles of, iii. 951. glands of the soft palate, iii. 952. tonsils or amygdalae, iii. 952. See also PHARYNX. AND MOUTH. Palatine artery, anterior, iii. 733. superior, i. 490. inferior, i. 486; ii. 556 ; iii. 949. bone, i. 728 ; ii. 210 ; iii. 725. canal, anterior, ii. 203. glands, iv. 426. hiatus, i.727- holes, accessory, ii. 210. nerves, ii. 286; iii. 951. great, ii. 286. lesser, ii. 28f>. middle palatine, ii. 286. posterior palatine, ii. 287. process, or plate, ii. 208. 210. veins, iv. 1404. Palato-g\ossus muscle, iii. 952 ; iv. 1121. 11S2. relations and action, iii. 952 ; iv. 1133. Pa/a/fo-pharyngeus muscle, ii. 947. 952 ; iv. 1121. relations and action, iii. 952. Prt/afo-staphylinus muscle, iii. 952. Palm-cats, dentition of the, iv. 911. Palmar arch of veins, superficial, iv. 1407. deep, iv. 1407- cutaneous nerves, ii. 524 ; iv. 757. fascia, ii. 525. disease of the, ii, 517. 525. ligaments. See Ligaments. Palmaris brevis muscle, ii. 520. relations and uses, ii. 520. longus muscle, ii. 264. 367. Palmellece, mode of reproduction of the, s. £20. Palmoglea macrococca, mode of reproduction of. s. 220. Palpebrce. See Eyelids. Palpebral, or tarsal, arches, iii. 93. arteries, i. 492 ; iii. 786. inferior, i, 492 ; iii. 93. superior, i. 492; iii. 93. conjunctiva, iii. 83. See Conjunctiva. fascia, 227- fissure, or rima palpebrarum, iii. 79. ligaments, external, iii. 81. internal, iii. 81. nerve, ii. 280. 289. external, ii. 289- internal, inferior, ii. 289. Palpebrarum orbicularis, ii. 211. Palpi as special organs of touch, iv. 1167. Palpitation of the heart, cause of, i. 416. Paludicella, ova of, development of, s. [127], [128]. Pampiniform ducts, iv. 982. PANCREAS, i. 127 ; ii. 20; iii. 483. 943 ; s. 81. definition, s. 81. I. Human anatomy, s. 81. situation, s. 81. relations, s. 81. shape, s. 82. right extremity or head, s. 83. left extremity, s. 8:3. upper border, s. 82. lower border, s. 83. anterior surface, s. 83. posterior surface, s. 83. size and weight, s. 83. general appearance, s. 84. internal structure, s. 84. duct of the pancreas, s. 8t. vessels, s. 86. arteries, s. 86. lymphatic vessels, iii. 2£6; s. 86. nerves, s. 86. II. Microscopic anatomy, s. 86. gland substance, s. 86. a., the basement or limitary membrane, s. 87. (3. epithelium, s. 88. •y. occasional appearance of a central cavity in each follicle, the epithel um lining it in a single columnal-looking layer, and leaving a central space unoccupied, s. 89. duct, s. 89. capillaries, s. 90. III. Comparative anatomy, s. 90. Invertebrata, s. 90. Gasteropoda, s. 90. Cephalopoda, s. 90. Vertebrata— Fishes, iii. 982 ; s. 91. pyloric appendages, s. 91. Reptilia, s. 94. Batrachia, s. 91. Ophidia, s. 95. Sauria, s. . c. haemorrhage, s. 110. d. structural changes, &. 110. 1. non-malignant ; cartilaginous transforma- tion, s. 110. steatomatous concretions, s. 110. c;>>tic tumours ; hydatids, s. 110. fatty degeneration, s. 111. 2. malignant, s. 111. scirrhus and carcinoma, s. 111. fungo-hsematoid disease, i. 112. e. calculus concretions in the pancreatic duct, s. 112. occurrence of fatty stools in connexion with pan- creatic disease, iv. 95 ; s. 112. See also GL\.\D. Pancreas Asellii, i. 479. See CARXIVORA. Pancreatic arteries, i. 195 ; s. 86. calculi, iv. 86. juice, i. 127. share taken by the pancreatic juice in the process of digestion, s. 398. vein, iv. 1414. PaHrmjion- fly, ii. 86*. Panorptna, or scorpion flies, a section of Insects of the order Neuroptera, ii. 864. characters of the section, ii. 854. PapilUe of various parts of the boily, iv. 1165. vascular and nervous supply to the papilla, iv. 1166. of cervix uteri, s. 659. lachry males, iii. 80. 91. of nipples, ill 246. o; the tongue, iv. 1136. circumvallate, iv. 860. 1122. 1136. fungiform, iv. 860. 1137. conical or filiform, iv. 860. 1138. simple, iv. S60. 1139. structure of, iv. 1 139. functions of, iv. 1140. morbid conditions of, iv. 1159. hypertrophy of circumvallate and fungiform papillae, iv. 1159. hairs on the conical or filiform papilla?, iv 1159. contrast afforded by the tongue in scarla- tina, iv. 1160. effusions into the papilla?, iv. 1161. extravasations of blood, iv. 1161. lymph, iv. 1161. denuded papilla?, iv. 1161. fur of the tongue, iv. 1 161. healing and reparation of the papilla?, iv. 1161. Papillary body of palpebral conjunctiva, iii. 85. PAR VAUL-.M NKK\E, iii. 881. origin, course in the cranium, iii. 882. ganglion superius, iii. 882. communicating filament with the glosso-pharyn- geal, iii. 8^2 auricular branch, iii. 883. passage of the vagus along the neck, iii. 8S4. branches, iii. 885. superior pharyngeal, iii. 885. inferior pharyngeal, iii. 885. middle pharyngeal of Valentin, iii. 885. superior laryngeal. iii. 886. external branch, iii 886. internal branch, iii. 886. vascular and cardiac branch, iii. 887. inferior or recurrent laryngeal, hi. 887. course of the vagus through the thorax, iii. 888. distribution of the vagus in the abdomen, iii. 889. left vagus, iii. 889. right vagus, iii. 890. connexion of the vagus and spinal accessory, iii. 890. physiology of the nervus vagus, iii. 891. do the roots of the v.-gus contain any motor filaments? iii. S91. PAR VAGUM NRRVF., physiology — continued. sensitive filaments, iii. 892. functions of the various branches, iii, 892. auricular branch, iii. 892. pharyngeal branches, iii. 892. laryngeal branches, iii. 893. effects of the laryngeal nerves on phona- tion, iii. 895. cesophageal branches, iii. 895. cardiac branches, iii. 896. pulmonary branches, iii. 896. to what extent do the filaments of the vagi act as incident nerves, iii. 897- morbid changes in the lungs after dividing the vagi. iii. 898. functions of the gastric branches, iii. 899. do the gastric branches of the vagus con- tain some motifcrous filaments ? iii. 899. effects of lesion of the vagi upon the sensations of hunger and satiety, iii. 899. upon the function of digestion, iii. 900. upon the secretion of gastric juice, iii. 900. upon the secretion of mucus upon the inner surface of the stomach and in- testines, iii. 900. upon the rapidity of absorption from the inner surface of the stomach, iii. 901. summary of conclusions respecting the lunc- tion of the nervus vagus, iii. 901. Paracentesis abdominis, operation of, i. 6. 9. recto-vesical, iii. 923. vesic* supra pubem. operation of, i. 9. 14. Paralysis, cerebral, iii. 58, 39. law of cerebral action in, iii. 681. exceptions to the law, iii. 681, 682. cause of the loss of speech which sometimes pre- cedes an attack of paralysis, iii. 710. general, cerebral hyperaemia in cases of, iii. 720 C. hemiplegic, iii. 720 Z. spinal, iii. 38. 40. produced by section of the facial nerve, iv. 552. of the urinary bladder, causes of, i. 402, 403. cause of the rigid and contracted state of the muscles which accompanies red softening of the brain, iii. 721 G. effects of strychnine on paralytic limbs, iii. 38. 40. influence of emotion and of certain respiratory acts on paralytic limbs, iii. 40. Paraphrenitis, ii. 6. Paraplegia, iii. 37. 40. state of the urine in cases of, iv. 467. Parasites, human, ii. 111-137. See EJJTOZOA. animal. See EwruzoA. vegetable, iv. 143. Parasitical animals in the blood, i. 429. in the cellular tissue, i. 516. ace|>halory>t, i. 517. Filaria medinensis, i. 517. parasitic growths, effect of, on the process of nutrition iii. 755. fishes, iii. 976. Paratrophia, or misnutrition, i. GO. Parenchyma, i. 127. Parietal bone, L 735. angles, i. 736. borders, i. 736. connections, i. 736. development, i.735. external surface, i. 735. inner surface, i. 735. foramen, i 735. fossa, i. 735. Pars intermedia of Kobelt, s. 712. Parmelia aipolia, organs of reproduction of, s. £29. 1'aronychia periostei, i. 449. a cause of abscess of the axilla, i. 362. Parotid fascia, iv. 423. fossa, i. 733. ganglions, i. 748. gland, ii. 481 ; iii. 581. S02 ; iv. 423. position, iv. 423. relations, iii. 902. form and dimensions, iv. 423. duct of the parotid gland, or duct of Steno, iv. arteries and veins of, iv. 424. lymphatics of, iv. 424. nerves of, iv. 424. morbid anatomy of the parotid, iv. 430. calculi of, iv. 83. or posterior border of the rami of the lower jaw. ii. 214. PAROTID REG i UN (in surgical anatomy), iii. 9C2. parotid gland, iii. 902. relations, iii. 9052. arteries, iii. 903. external carotid, iii. 903. internal maxillary, iii. I (.3. trans versa) is faciei, iii. (> :3. posterior auricular, iii. !>03. . 836 GENERAL INDEX. PAROTID REGION — continued. veins, iii. 903- temporal and internal maxillary, iii. 903. posterior auricular, iii. 903. transverse facial, iii. 903. external jugular, iii. 903. nerves, iii. 903. great auricular, iii. 903. branches, iii. 903. auiicular, superficial, iii. 903. deep, iii. 903. auriculo-temporal, iii. 903. superficial temporal, iii. 19. auricular branch, iii. 903. portio dura, iii. 903. posterior auricular, digastric, and stylo-hyoid branches, iii. 904 temporo-facial division, iii. 904. cervico-facial division, iii. 904. lymphatic glands, iii. 904. Parouarium, the, s. 593. structure and development, s. 593. abnormal states, s. 597. Parrot, its mode of climbing and apparatus for prehension, iii. 451. eyelids of, iii. 97. vocal organs and voice of the, iv. 1500. Parrot-fishes, dental apparatus of, iii. 979. teeth of the, iv. 871. 878. Parthenogenesis, s. 37. PARTURITION, MECHANISM OF, iii. 904. in the lower animals, iii. 90*. attitude and position of the foetus, iii. 906. in the human subject, iii. 907. presentation of the head, iii. 907. first position, iii. 907. second position, iii. 907. presentation of the face, iii. 908. first position, iii. 908. second position, iii. 90S. presentation of the lower extremities, iii. 908. cross presentation, iii. 908. mechanism of the pelvis in parturition, s. 146. changes in the uterus after parturition, s. 658. process of involution of the gravid uterus, s. 658. changes in dimensions and weight, s. 658. metamorphosis and restoration of the component tissues, s. 659. office of the uterus in parturition, s. 672. general sketch of the labour process, s. 672, 673. peristaltic action of the uterus and its cause, s. 673. rhythmic action of the uterus and its cause, s. 674. influence of the different nervous centres upon the uterus in puriu ition, s. 675. the exciting cause of labour, s. 677. part taken by the abdominal muscles in promoting, i. 17. immediate agent of expulsion in, iii. 721 L. influence of the obliquely contracted pelvis upon par- turition, s. 202. pathological condition of the uterus after parturition, s. 702. irregular contraction; hour-glass contraction (ar- rested peristaltic action), s. 702. incomplete and retarded involution, s. 702. puerperal inflammations, s. 702. endo-metritis, s. 702 metro-phlebitis, s. 703. metro-peritonitis, s. 703. blood-dycrases, s. 704. Passcres, pelvis of the, s. 169. " Pastern, great," of the horse, iv. 719. Patella, or Knee-pan, ii. 1<>8. development, ii. 168. form and position, ii. 163. structure, ii. 168. ligaments of, i. 251 ; iii. 45, 46. surfaces, ii. 168. compared with that of the lower Mammalia, ii. 1G8. fractures, iii. 69. dislocations, iii. 73. rupture of ligament of patella, iii. 78. Patella vulgaris (limpet), nervous system of the, i. 113; iii. 605. Pathctici nerves, ii. 370 ; iii. 707. distribution, ii. 370. function, ii. 370, 371. origin and cranial course, ii. 370. See also ORBIT, MUSCLES OF THE. Paunch, or pause, of Ruminantia. ii. 11 ; s 535. Pavilion, or infundibuluin, of Fallopian tube, s. (501. Pearls, formation of, i. 713. Pecan', stomach of the, s. 303. Pecten, or marsupium nigrum in Aves, ii. 203. Pecten (or scallop), nervous system of the, iii. 604. Pectines of scorpions. See Scorpions. Pectinibranchiuta, ii. 378. See GASTEROPODA. Pec ti iieus muscle, s. 137. nerves to, iv. 763. Pectoral extremities of Marsupialia, iii. 280. Pecloralis major muscle, i. 217. 359. minor, i. 359; iv. 57 o. Pedate larvze of insects, mode of locomotion of, iii. 441. Pediastrum, mode of reproduction of the, s. 2i.'3. Pedicellina Belgica, a species of Polypifera, iv. 59. mode of reproduction of, iv. 59, GO. ova of, s. 23. development of true ova of, s. 23. [127]. Pediculidce, ii. 868. Pedunculi, or crura, cerebri, iii. 678, 679. of crus cerebelli, iii. 693. interior, iii. 693. middle, iii. 693. superior, — processus cerebelli ad testes, or cerebro- cerebellar commissures, iii. 693. of the pineal gland (habena?), iii. 677. Pellia epiphylla, vegetative system of, s. 235. first period, — germination of the spores, s. 235. antheridia, s. 235. archegonia, s. 235. second period, — development of the embryo, s. 236. changes preparatory to the development of the spores, 8. 236. Pelonaia, a genus of Tunicata, iv. 1193, et scq. Pelonaiadte, a family of Tunicata, iv. 1193, ct scq. characters of the family, iv. 1193. Pelvic fascia, ii. 231 ; iii. 933. PELVIS, s. 114. definition, s. 114. innominate bone, s. 114. its office, s. 114. superior border, s. 114. anterior border, s. 114. inferior border, s. 115. posterior border, s. 115. external or femoral surface, s. 115. the acetabulum or cotyloid cavity, s. 116. descending ramus or body of the ischium, s. 116. horizontal ramus or body of the pubis, s. 116. ascending ramus of the ischium, s. lid. descending ramus of the pubis, s. 116. obturator or thyroid foramen, s. 116. sub-pubic or obturator groove, s. 116. internal or pelvic surface, s. 117. iliac tuberosity, s. 117. sacral or auricular surface, s. 117. internal iliac fossa, s. 117. ilio-pectineal line, s. 117. internal structure of the innominate bone, s. 117. sacrum, s. 118. its office, s. 118. base, s. 118. apex, s. 118. anterior or pelvic surface, s. 118. posterior surface, s. 118. lateral surfaces, s. 119. internal structure of the sacrum, s. 119. coccyx, s. 120. development of the pelvis, s. 120. innominate bone, 8. 120. sacrum, s. 120. coccyx, s. 121. pelvic articulations and ligaments, s. 121. lumbo-pelvic articulations, s. 121. proper or intra-pclvic articulations, s. 121. sacro-coccygeal joint, s. 122. motions of the joint, s. 122. sacro-iliac joints, s. 122. cartilages lining these articulations, s. 122. inter-osseous ligaments, s. 123. superior sacro-iliac ligament, s. 123. anterior ligament, s. 123. posterior sacro-iliac ligaments, s. 123. the deep and superficial layers of fi- bres, s. 123. ilio lumbar ligament, s. 124. great sacro-sciatic ligament (Hgamentum pelvis posticum magnus), s. 124. lesser or internal sacro-sciatic ligament (ligamentum pelvis posticum patvum), s. Ii4. movements of the sacro-iliac joint, s. 125. pubic symphysis, s. 125. anterior pubic ligament, s. 125. posterior pubic ligament, s. 125. superior pubic ligament, s. 125. inferior or sub-pubic ligament, s. 126. movements of the pubic symphysis, s. 126. obturator or thyroid membrane, s. 126. general appearance of the articulated pelvis, s. 126. its interior aspect, s. 126. lateral aspects, s. 126. posterior aspect, s 126. superior aspect, s. 126. false pelvis, s. 127. brim of the pelvis, s. 127. cavity of the true pelvis, s. 127. inferior aspect, s 127. differences of the pelvis in the sexes, s. 158. inferior aperture of the male pelvis, iii. 919. position and shape of the, iii. 919.- axes of the male pelvis at difierent ages, iii. 919. GENERAL INDEX. 837 PELVIS— continued. measurements of the pelvis, s. 129. at the brim, s. 129. in the cavity, s. 129. at the inferior strait, s. 129. table of measurements of the pelvis, s. 1:70. inclination of the pelvis, s. 151. angles of the anterior and posterior pelvic walls with the transverse vertical plane, s. 133. ilio-ischial angle, s. 1:34. angle of ischio- pubic arch, s. 134. axes of the pelvis, s. 1:34. axis of the brim, s. 135. of the inferior outlet, 8. 135. general development of the pelvis, s. 135. the pelvis of infants, s. 136. in advanced adult age, s. 157. muscular attachments of the pelvis, s. 137. ' 1. muscles acting on the trunk and spine, 8. 137. posterior spinal group, s. 137. abdominal group, s. 157. 2. muscles acting on the leg, s. 137. flexor group, s. 137- extensor group, a. 1.37. adductor group, s. 137. abductor group, s. 137. rotator group, s. 137. 3. musclo* acting on the perineum and genitals, s. 138. posterior perineal group, a. 138. anterior perineal group, s. 138. fascial attachments, s. 138. lumbar fascia, s. 138. abdominal fascia?, s. 138. crural fascia or fa^cia.lata, ». 138. pelvic fascia, s. 138. perineal fascia, s. 13S. crura of the penis or of the clitoris, s. 138. mechanics of the human pelvis, a. 138. in regard to parturition, s. 146. comparative anatomy of the pelvis, s. 148. pelvis of Negro, s. 148, 149. pelvis of the Bushman, s. 149. Tahitian, s. 150. Australian, s. 150. Javanese, s. 150. measurements of pelves of various races : — 1. the oval form, s. 150. 2. the round form, s. 150. 3. the square or four-sided form, s. 150. 4. the cuneiform or oblong form, s. 150. pelves of the Simiae, s. 151. of the Carnivora, s. 154. of the Phoca?, s. 155. of the Pachydennata, s. 155. Ruminantia, s. 157. Rodentia, s. 1.58. Marsupialia, iii. 282; s. 159. Monotremata, s. 161. Edentata, s. 161. Insectivora, s. 16*. Cetacea, s. 165. Birds, s 165. Reptiles, s. 170. Fishes, s. 172. table of comparative pelvic angles, s. 1~4. serial homologies of the pelvic bones and liga- ments, s. 174. anatomical differences in the conformation of the- pelvis by which the several races of mankind may be dis- tinguished from each other, iv. 1331. PELVIS, ABNORMAL ANATOMY OF THE, s. 178. pelvic deformities and obstructions, iv. 945; s. 178. 1. Normal irregularities, s. 178. equable deviations, s. 178. pelvis ajquabiliter justo major, a. 178. pelvis a?quabiliter justo minor, s. 178. cause, ?. 179. irregularities from imperfect development — infantine pelvis, s. 179. masculine pelvis, s. 180. irregularities of the pelvi-vertebral angle, s. 181. 2. Distortions, a. 181. distortions affecting the brim only or princi- pally, s. 181. distortions affecting the cavity only or princi- pally, s. 182. vertical flatness of the sacrum, s. 1S2. inward projection of the sciatic spines, s. 182. distortions affecting the outlet only or pr'nci- pally, s. 183. contraction of the transverse diameter, s. 183. special cause of this deformity, 8. 183. contraction of the anterc-posterior dia- meter, s, 183. distortions affecting the whole pelvis, s. 185. ovate, elliptical, or reniform pelvis, s. 185. ilia and ischia, s. 185. symphyj-is pubis, s 185. PELVIS, ovate, ellii tic.il, or reniform — c9. diagnosis, s. 210. Pelvis of kidney, iv. 238. epithelium of pelvis of kidney, iv. 254. ovalis of ear, ii. 530. Pemphigus of the foetus in utero, ii. 333. PENIS, iii. 909. definition, iii. 909. comparative anatomy, iii. 909. in Infusoria and'Rotifera, iii. 9C9. in Entozoa, iii. 909. in Annelida, iii. POP. in Cirrhopoda, iii. 909. in Crustacea, iii. 909. in Insecta, iii. 910. in Mollusca, iii. 910. in Vertebrate, iii. 910. Fishes, iii. 910. Amphibia, iii. 910. Ophidia, iii. 910. Sauria, iii. 910. Chelonia, iii. 910. Aves, iii. 911. Mammalia, ii. 423 ; iii. Pll. Quadrumana, iii. 911. in Man, iii. 911. integument, iii. 911. prepuce, Hi, 910. fra?num pra?pntii, iii. 910. subcutaneous areolar tissue, iii. 912. fascia penis, iii. 912. corpus cavernosum, iii. 912. structure, ii. 145. 42>. 445 ; iii. 9i2. trabecula?, iii. 912. septum pectiniformo, iii. 913. vasco-cellular structure, iii. 913. contractile fibrous tissue, iii. 91J. corpus spongiosum and plans penis, ii. 423, 424. 445. iii. 914; iv. 985. structure, iii. 914. mucous membrane, iii. 914. supposed muscular fibres of the urethra, iii. 915. muscles, ii. 446; iii. 915. erector j>enis, iii. 915. acce'eratores urina?, iii. 915. i-rl.i,. rmlbosus, iii. 915. compressor venae dorsalis penis, iii. 916. 838 GENERAL INDEX. PENIS in Man — continued. arteries, ii. 146; iii. 916. artcria corporis bulbosi, iii. 916. arteria corporis cavernosi, iii. 916. arteria dorsalis penis, iii. 917. investing membrane, ii. 146. veins, iii. 917. venae corporis bulbosi, and venae corporis cavernosi, iii. 917. dorsal vein, i. 388 ; iii. 917. ultimate arrangement of the blood-vessels, iii. 917. arteria? helicinae, iii. 917. lymphatic vessels, iii. 918. nerves, iii. 918 ; iv. 766. development, iii. 918. local changes consequent on puberty, ii. 459. mode of union of the arteries with the veins, ii. 446. bone of penis in some animals, ii. 44o. urethra. See URETHRA. causes of erection, ii.445, 446. influence of the spinal cord on the, iii. 721 B, 721 E, 72 IT. condition of the urethra when the penis is erected and when the seminal secretion is to be expelled, iv. 1255. analysis of the act of erection, iii. 721 L. chordee, iii. 721 L. adhesion of inferior surface of penis to scrotum, a cause of spurious hermaphroditism, ii. 691. Penicillium verticillatum, organs of reproduction of, s. 224. Pennatula grisea, a species of Polypifera, iv. 38. phosphorescence of, iv. 38. Pennatulidee, a family of Polypifera, iv. 20. 38. characters of the family, iv. £0. genera, iv. 20. Penniform ruga? of uterus, a. 629. Tlivrtews, case of, iv. 986. Pepsine, iv. 166. Peptone, or albuminose, s. 336. chemical composition of, s. 336. Pepper considered as an article of food, s. 391 Perameles (or bandicoots), a genus of Marsupialia, iii. 260, et seq. characters of the genus, iii. 260. Perch, climbing, conformation of the, iii. 986. Perching birds ( Insessores), characters of, i. 267. Percidce, a family of Fishes, iii. 956, et seq. characters and genera of the family, iii. 956. Perforans Casserii nerve, i. 361. Perforated space, posterior, iii. 703. Perforating arteries, ii. 248. first, second, third, and fourth, ii. 248. of fore-arm, posterior, iv. 224. Pericarditis, course of the disease, ii. 643. termination, ii. 644. characters of the urine in, iv. 1290. cases of, in the foetus in utero, ii. 334. Pericardium, ii. 597, 598 ; iv. 522, 523. uses of the pericardium, ii. 598. vessels within the pericardium, relative position of the, ii. 598. affections of the pericardium in the foetus in utero, ii. 334. congenital absence of the pericardium, ii. 633. hydrops pericardii, ii. 645. ossilication of the, ii. 266. pneumopericardium, ii. 645. softening, iv. 708. collections of fluid, syncope by, i. 797. cardiac pericardium of the dolphin, i. 57. See HEART. Perichondrium, i. 248. Pericranium, i. 748, 749- Peridinctadce (wreath animalcules), a family of Polygastric animals, iv. 4. characters of the family, iv. 4. Perilymph, or liquid of Cotugno, ii. 536. Perimetritis, s. 688. Perincal artery, superior, s. 713. superficial, iii. 92S. transverse, iii. 929. hernia, iii. 932 muscle, transverse, iii. "20. nerve, external, iii. 938; iv. 439. 766; s. 714. internal, iv. 4 ?9. cutaneous, iv. 767. fascia, s. 1.38. deep, s. 138. superficial, s. 138. PERINEUM (in surgical anatomy), iii. 919. bony and ligamentous boundaries, iii. P19. axes of the pelvis at different ages, iii. 919. rectum, iii. 920. course, &c. iii. 92'). relations, iii 921. coats, iii. 921. bladder, vesiculae seminales, and vasa deferentia, iii. "22. ureihra, iii. 923. prostatic portion, iii. 924. membranous portion, iii 925. bulb and spongy portion, iii. 925. PERI NEUM — continued. dissection, iii. 926. superficial compartment, iii. 926. integument, iii. 926. superficial fascia, iii. 927. central tendinous point of the perineum, iii. 928. superficial perinea! artery and veins, iii. 928. inferior or superficial division of the pudic nerve, iii. 928. transversalis perinei artery, iii. 929. accelerator urinae muscle, "iii. 929. erector penis, iii. 929. transversus perinei, iii. 929. bulb of the urethra, iii. 930. triangular ligament, iii. 930. Cowper's glands, iii 930. Guthrie's muscles, iii. 930. arteries of the bulb, iii. 931. internal pudic arteries, iii. 931. deep compartment, iii. 932. Wilson's muscles, iii. f'32. membranous portion of the urethra, iii. 932. prostate gland, iii. 932. vesico-prostatic plexus of veins, iii. 933. irregular artery sometimes found along the side of the prostate, iii. 933. application of the anatomy of this part to prac- tical purposes, iii. 934. muscles acting on the perineum, s. 138. subcutaneous adipose tissue in the, i. 177. posterior portion of the perineum, i. 174. See ANUS. passage of the testicle into the perineum, iv. 988. fissure of the, a cause of spurious hermaphroditism, ii. 691. Periosteum, composition of, i. 433; ii. 264. outer surface, ii. 264. external surface, i. 433; ii. 264. pathological conditions of, i. 441, et seq. uses, i. 433; ii. 264. vascularity, i. 433. See also BONE, NORMAL ANATOMY ; OSTEOGENY. Periostitis, i. 444. 449. case of. ii. 788. of cranium, i. 749. Peristalsis, or transverse constriction of the stomach, s. 313. Peristaphylinus externus muscle, iii. 951. Peritoneal covering of ovary, s. 548. inflammation of, s. 574. or serous, lamina? of the bladder, i. 380. PERITONEUM, i. 13. 380. 387; iii. 935 ; iv. 522; s. 341. definition, iii. 935. in males and females compared, iii. 93.5. relations of the diaphragm to the peritoneum, ii. 4. continuity of the peritoneum traced, iii. 936. omenta, mesenteries, and ligaments, iii. P40. falciform ligament of the liver, iii. 940. coronary ligament of the liver, iii. 940. triangular ligaments of the liver, iii. 941. lesser or gastro- hepatic omentum, iii. 937. 941. splenic omentum, iii. 941. great omentum, iii. 941. use of, iii. 912. homology of, iii. P42. transverse mesocolon, iii. 942. mesentery, iii. 943. ascending and descending mesocolon, &c., iii. 943. appendices epiploicae, iii. 943. recto-vesical folds, iii. 943. bro.id ligaments of the uterus, iii. 943. recto-uterine and vesico-uterine folds, iii. 943. other slight folds and depressions, iii. 943. the serous coating of the various abdominal viscera, iii, 943. external or adherent surface of the peritoneum, iii. 944. parietal portion, iii. 944. visceral portion, iii. 944. abnormal adhesion and other results of peritonitis, iii. 94-5. minute anatomy. See SEROUS MEMBRANE. softening of the peritoneum, iv. 7C8. malformation, i. 508. Peritonitis, iii. 945. abnormal adhesions and other results of peritonitis, iii. "45. effects of, on the action of the heart, i. 797. Peritrema of the stigmata of Arachnidans, i. 1^04, 205. Perocephalus aprosopus, iv. 962. Peroneal artery, anterior, ii. 267 ; iii. 134. posterior, ii. 267. origin and course, iii. 134. relations, iii. 133. operations for ligaturing, iii. 134. nerve (external popliteal), iii. 132 ; iv. 62. 768. branches: peronaoal cutaneous, iv. 7fi8 peronajal saphaenus, iv. 768. superior external articular, iv. 763. inferior external articular, iv. 768. Pcroncvs brevis muscle, i. 152; iii. 131. 138. action and relations, iii. 138. GENERAL INDEX. 839 Peroneus — continued. longus musde, ii. 355. 357 ; iii. 131. 138. action and relations, iii. 138. tendon of, j, 149. 152. tertius muscle, ii. 352 ; iii. 131. 137. relations, iii. 137. action, iii. 138. tendon of, i. 149. Peropliora, a genus of Tunicata, iv. 1188. characters of the genus, iv. 1188. Persistence of the urachus, i. 39S Perspiration or sweat, sensible, i. 127 ; ii- 149. constituents of, ii. 149. quantity excreted in twenty-four hours, ii. 149. See also SWEAT. Peru, evidences of the high degree of civilisation attained by the ancient inhabitants of, iv. 13t>U. Pes anserinus, i. 485; iii. 581. equinus, anatomical characters of, ii. 349. Petaurists, or Flying Opossums, iii. 263. Pelatn us, a genus of Marsupialia, iii. 263, et seq. characters of the genus, iii. 263. species of the, iii 26+. Pelaurus flaviventer, iii. 264. pigma?us, iii. 2fi4. taguanoides, iii. 224. Petechia, causes of, i. 42.'. Petit, canal of, ii. 193- Petro-occipital suture, i. 737. Petro-sphenoidnl suture, i. 737. 2'etromt/zon marinus (or lamprey), iii. 976. teeth and parasitic habits of, iii. 976. respiratory apparatus of, iii. 976. organs of generation of, iii. 1006. Petrosal sinus, inferior, or basilar, sinus, i. 732; iv. 1406. sulcus, i. 733. nerve, superficial, ii. 554 ; iv. 545. small petrosal, iv. 54C. minor Arnolui nerve, ii. 555. tertius nerve, ii. 555, note. Petrous branch of Vidian nerve, cranial or superficial, ii. 288. portion of the temporal bone, i. 733. Peyer's patches, s. 35fi. See Follicles, intestinal; STOMACH AND INTESTINE. in the intestine of the giraffe, s. 539. glands, iv. 839. Peziza, reproductive system of, s. 227. Phacochcerus, or wart-hogs of Africa, iv. 870. teeth of the, iv. 870. See PACHYDEH.MATA. Phagedcenic ulcers rf the tongue, iv. 1157. Phal.nigeal joints, motions of the, ii. 345. P/iatatiger, Flying, mode of flight of the, iii. 430. organs of voice of the, iv. 1491. Phalanges of toes, metatarsal, ii. 342. middle, ii. 342. ungual, ii. 342. structure and development, it 342. of fingers, ii. 5<;7. 510. articulations, ii. 507. general characters, ii. 507. metacarpal, middle, and ungual phalanges, ii. 507. structure and development, ii. 507. motions of the joints, ii. 510. abnormal conditions, ii. 511. Phalangista, a genus of Marsupialia, iii. 262, et seq. characters of the genus, iii. 262. species of, iii. 262, 2^3. Phalmigista Cookii, iii. 262, ct seq. Phallnsia intestinalis, nervous system of the, iii. 603. Phanerogamia, vegetative system of the, s. 246. Phanerogamia Gymnospermia, s. 246. Angiospermia, s. 248. Hippuris vulgaris, s. 249. Orchis morio, s. i'50. the anther and the pollen-cell, s. 251. review of the analogies which present themselves in the history of the development of the reproduc- tive organs of the higher Cryptogamia and of the Phanerogamia, s. 252. 1. analogies existing between the ovule, the anther, and the sporangium, s. 252. 2. analogy between the embryo-sac, pollen-cell, and parent cell of four spores, s. 252. origin and development of germ-cells in special organs destined for their reception, which are capable of transformation into rudiments of new plants, without the concurrence of two organs of opposite functions, 8. 253. Pharyngeal artery, inferior, or ascending, i. 487; ii. 55(5; iii 949. proper pharyngeal branch, i. 487. posterior meningeal. i. 487. origin and course, iii. 949. superior pharyngeal, or pterygo-palatine, artery, i. 4!'0. nerve, ii 288. branches of glosso-pharyngeal nerve, ii. 496. branch of vagus nerve, superior, iii. 885. 892. 901. inferior, iii. 885. S'JS. middle, of Valentin, iii. 885. 893. Pharyngeal nerve — continued. branch of vagus, superior laryngeal, iii. 886. 893. external branch, iii. 886. internal branch, iii. 886. vascular and cardiac branch, iii. 887. inferior or recurrent laryngeal, iii. 8S7. muscles, iii. 105. plexus of nerves, ii. 497. region, posterior, iii. 582, space, posterior, iii. 570. vein, iii. 949 ; iv. 1406. PHARYNX AND MOUTH, iii. 111. 945. definition, iii. 945. 1. fibrous membrane, iii. 945. muscles, iii. 105. 946. constrictor pharyngis inferior, iii. 946. medius, iii. 946. superior, iii. 946. stylo-pharyngeus, iii. 947. palato-pharyngeus, iii. 947. 2. general review of the attachments of the pharynx, iii. 947. 3. the cavity and its openings, iii. 948. 4. mucous membrane and glands, iii. P48. 5. vessels and nerves, iii. 9*9. See also PAR VAGUM ; GLOSSO-PHARYNGEAL NERVB; SPINAL ACCESSORY NERVE. mouth, iii. 949. lips, iii. 949. cheeks, iii. P50. palatine aich and gums, iii. 950. gums, iii. 951. velum palati. iii. 951. muscles of, iii. 951. circnmflexus palati, iii. 951. levator palati, iii. 952. palato-pharyngeus, iii. 952. palato-glossus, iii. 953. azygos uvula?, iii. 952. glands of the soft palate, iii. 952. tonsils, or amygdalae, iii. 952. course of the mucous membrane, iii. 953. functions, iii. 945. 953. morbid anatomy of the pharynx and mouth, iii. 954. congenital "malformations, iii. 954. foreign bodies, iii. 954. structural changes, iii. 954. abscesses, iii. 954. abscesses dependent on caries of the cer- vical spine, iii. 583. ulceration, iii. 954. pohpi, iii. 954. pouching of the mucous membrane, iii. 954. cancrum oris, iii. 954. calculi of. iv. 83. congenital malformation of the, iii. 760. PArtry/^'o-staphylinus muscle, iii. 952. relations and action, iii. 952. Phascogale. a genus of Marsupialia, iii. 259, et seq. characters of the genus, iii. 259. Phascogale pencillata, iii. 259. Phascolarctus, a genus of Marsupialia, iii. 265, et sfq. characters of the genus, iii. 2i;5. Phascolomi/s (wombat), a genus of Marsupialia, iii. 267, et seq. characters of the genus, iii. 267. Phascum cuspidatum, development of the antheridia and archegonia of, s. 238. development of the fruit, a. 238. spores, s. 239. Phasianus gallus (fowl), nervous system of the, iii. 622. Phialina, or spigot animalcules, iv. 13. Philodina, a genus of Rotifera, iv. 407. ro.-ea, iv. 406. Philodinea, a family of Rotifera, iv. 406. characters of the family, iv. 406. genera, iv. 407. Phlebectesis, iv. 1397. various forms of, iv. 1397. Phlebitis, iii. 49. 50 ; iv. 1,391, 1392. plastic phlebitis, iv. 1392. cause of, iv. 1393. suppurative phlebitis, iv. 1394. obliteration of veins, iv. 1395. healing of wounds in veins, iv. 1395. effects of ligatures on veins, iv. 1396. uterina, characters of the urine in, iv. 1291. Phlcbolites. phleboliths, or vein-stones, iv. 89. 14CO. chemical analysis of, iv. 89. 1400. origin and development of, iv. 1400. Phlebotomy, operation of, on the veins of the arm, ii. 65. syncope produced by the operation of, i. 228. Phlegmasia dolens, i. 515 ; iii. 128 ; iv. Iui4. Phlegmatic temperament, iv. 936. Phlegmon, i. 513. of cellular tissue between the conjunctiva and sclero- ticn, iii. 85. peri-uterine, s. 688. Phoca vitulina, or common seal, organs of voice of the, iv. 149J. 810 GENERAL INDEX. Phocenic acid, ii. 2.34. neutral salts of (phocenates), ii. 234. Phocenine, chemical composition of, ii. 234. Phocidte, dentition of the, iv. 914. pelvis of, s. 155. PJionation, effects of the lesion of the recurrent nerves on, iii. 895. Phosphate of ammonia and magnesia, in morbid concre- tions, iii. 806. analysis of, iii. 806. calculus of, iv. 80. Phosphate of lime in the composition of the blood, i. 410. in morbid concretions, iii. 80(1 analysis of, iii. 806. calculus of, iv. 80. Phosphate of magnesia in the composition of the blood, i. 410. Phosphates, earthy, deposits of, in urine in disease, iv. 1283. mixed, or fusible calculus, iv. 80. Phosphorescence. See LUMINOUSNESS, ANIMAL. of Cephalopoda, i. 536. of Limax noctilucus, ii. 404. of Pennatulidae, iv. 38. of Pyrosomidae, iv. 1192. 1229. effect of fresh water on phosphorescent marine animals, iv. 1230. Phosphoric acid, method of determining the presence of, in organic substances, iii. 80-2, 803. in urine, iv. 80. Phosphorus in the composition of the brain, iii. 588. variation of the quantity in different periods of life, and its small amount in idiocy, iii. 588. Phrenic artery, superior, iv. 822. inferior, i. 189. 194. nerve (diaphragmatic, internal respiratory) ii. 3, 4: iv. 754.815, 816. left phrenic, iv. 754. right phrenic, iv. 754. veins, inferior, iv. 1413. P/zrewJco-gastric ligament of Soemmering, iii. 941. J'hrenitis, or inflammation of the diaphragm, ii. 6. Phreno-g&stric omentum, s. 309. Phrenological views of the connexion of the cerebellum with the sexual functions, iii. 722 S. Phthisis pulmonalis, conformation of the thorax in, iv. 1038. aphonia preceding or attendant on, iii. 123. three stages of, s. 293. characters of the urine in, iv. 1293. communicated by means of morbid saliva, iv. 420. death by, i. 264. Phthisis laryngea, iii. 120. 126. causes of, and localities attacked, iii. 120. progress of the disease, iii. 121. post-mortem appearances, iii. 120, 121. symptoms, iii. 121. treatment by an artificial opening in the trachea, iii. 121. &utris, or animating principle of Aristotle, iii. 143. Phylhydrida, a sub-tribe of Coleoptera, ii. 860. Phyllirhoe bucephalum, genital organs of, s. [107.] Pkymatin, iv. 107. Physalus, locomotive powers of the, iii, 433. Physosfrada (Acalcphse), i. 36. Pkysometra, s. 697, 698. humida, s. 698. putrida, s. 698. Plu/tophni'a, a tribe of Insects of the order Coleoptera, i. 563 ; ii. 862. characters of the sub-tribe, i. 563 ; ii. 862. Pht/toxoa. See POLYPIFERA. Pi'a mater, iii. 633. of the spinal cord, iii. 633. of the brain, iii. 634. continuations of the pia mater into the cerebral ven- tricles, iii. 634. choroid plexuses of the lateral ventricles, iii. 634. choroid plexuses of the fourth ventricle, iii. 635. crystalline formations in the chorcid plex uses, &c., iii. 635 connexions, &c., of the pia mater, iii. 636. in reference to pathology, iii. 636. abnormal anatomy of the cranial pia mater, iii. 717. injected state of the vessels, iii. 717. tubercle, iii. 717. abnormal anatomy of the spinal pia mater, iii. 713. congestion of the venous sinuses, iii. 713. causes of spinal apoplexy, iii. 713. inflammation of the pia mater, iii. 713. " Picking of the bed-clothes" a sign of approaching death, i. 800. Picromel, or Gallenstoff, i. 375. Pig, stomach of the, s. 303. urine of tho, iv. 1280. See PACHYDERM AT A ; Sus scrofa. Pigeon (Columba), nervous system of the, iii. 622. migrating pigeons of America, iii. ]8. Pigeon-breast, iv. 1039. Pigment in the grey nervous matter, iii. 649. granules of the skin, iii. 496. melanic, iv. 116. See PRODUCTS, ADVENTITIOUS. Pigmentum nigrum, ii. 180. chemical composition of, ii. 181. uses, ii. 181. Pt'limiction, cases of, iv. 142. Pillar, central, or axis of cochlea?, ii. 531. Pillars of diaphragm, ii. 3. of the fauces, iii. 951 ; iv. 1121. of fornix, iii. 676. anterior, iii. 676. posterior, iii. 676. Pill-box hydatid, ii. 117. See ENTOZOA. Pilobolus, mode of development and reproduction of, s. 218. Pilularia, development of, s. 245. Pineal gland, i. 72 ; iii. 676, 677. acervulus of the, iii. 677- peduncles or haben^e, iii. 677. Pinguedo, i. 57. Pinnal cartilages, iii. 726. Pinnipeclia, Weberian organ in, iv. 1418. Pinus Austriaca, development of, s. 247. maritima, development of, s. 247. sylvestris, development of, s. 217. Pipe-fishes, iii. 986. 1010, 1011. PISCES, i. 114; iii. 955. general characters, iii. 955. classification, iii. 956. osseous system, iii. 957. skeleton of Osseous Fishes, i. 438; iii. 958. vertebral column, iii. 9.r>8. ribs and sternum, iii. 959. cranium, iii. 959. face, iii. 959. anterior extremities, iii. 961. posterior extremities, iii. 962. fin rays of the extremities, iii. 962. vertical fins, iii. 962. interspinous bones, iii. 962. rays of the vertical fins, iii. 962. skeleton of Chondroptervgii, i. 438 ; iii. 963. skull, iii. 963. branchial apparatus, iii. 964. ribs and sternum, iii. 965. anterior extremities, iii. 965. posterior extremities, iii. 966. skeleton of Dermapterygii, iii. 966. skeleton of Branchiostoma, iii. 967. cartilages of the articulations, i. 249. pelvis of fishes, s. 1~2. See also OSSEOUS FISHES. arlhroidal system, iii. 967. muscular system, iii. 968. great lateral muscles, iii. 968. superior and inferior slender muscles, iii. 908. muscles of the pectoral fins, iii. 968. of«he ventral fins, iii. 963. of the jaws, iii. 968. of the palato-tympanic arch, iii. 968. of the operculum, iii. 969. of the os hyoides, iii. 969. of the branch iostegous membrane, iii. 9i9. branchial and pharyngeal apparatus, iii. 969- peculiarities of the muscular system in particular fishes, iii. 969. in Ostracions, iii. 969. in Raidas, iii. 969. muscles of the jaws in Cartilaginous Fishes, iii. 970. in Sharks, iii. 971. in Petromyzonida?, iii. 971. tegumentary system, iii. 971. the skin in general, iii. 971. pigment, iii. 972. mucous follicles, iii. 972. scales, iii. 973 ; s. 480. teeth of scales, iii. 974. chemical composition, iii. 974. organs and mode of locomotion of, iii. 436. in fishes shaped like the salmon, cod, and mackarel, iii. 437. flat fishes, iii. 437. analysis of the act of swimming in fishes, iii. 438. amount of resistance offered by the various forms, iii. 437. velocity of fishes, iii. 438. powers of flight of fish, iii. 429. muscular power of the salmon in springing into the air, ii. 62. digestive organs, s. SCO. oesophagus, s. 300. stomach, s. 300. intestine, s. 300. appendices pyloricae, s. 300. teeth, iii 975 ; iv. 873. in Cyclostomatous Fishes, iii. 976. position, form, mode of implantation, and deve. lopment, iii. 977 ; iv. 873. 880. examples of peculiar dentition, iii 978. Cyprinidse, s. 979. Scari, iii. 979. Diodons and Tetrodons, iii. 980. Saw-fish, iii. 980. substance of the teeth of fishes, iv. 877. GENERAL INDEX. 841 PISCES — continued. oesophagus, iii. 981. stomach, iii. 981. pyloric appendages, s. 91. intestinal canal, iii. 981. salivary glands, iii. 982. pancreas, iii. 982. liver, iii. 175. 982. renal organs, iv. 232. spleen.iii. 983. lymphatic system, iii. 983. organs of respiration, iii. 985. in Osseous Fishes, iii, 985. in Lophobranchii, iii. 986. in Sturionidae, iii. 986. in Flagiostome Cartilaginous Fishes, iii. 986» in Cyclostomata, iii. 987. in Branch iostoma, iii. i>88, hyoid apparatus, iii. 988. branchial cavity, iii. 988. circulatory system, i. 616 ; iii, 9o8. heart, iii. 988. bulbus arteriosus and branchial artery, iii. 989. vascular system, iii. 989. branchial and systemic arterial vessel*, iii. 989. systemic veins, iii. 990. organs of respiration of fishes, s. 281. 286. air-bladder, s. 281. formation and uses of, iii. 43fi. mucous membrane and vascular system of, 8. 287- thyroid gland in, iv. 1109. respiratory movements of fishes, iv. 1019. (respiratory and circulatory apparatus in Lepi- dosiren,) iii. 990. portal system of veins, iii. 992. lateral system of vessels, iii. 992. nervous system, iii. 614. 992 brain of fishes, iii. 616. 992. weight of the brain compared with that of the body, iii. 618. olfactory tubercles, or first cerebral mass, iii. 618. optic lobes, or second cerebral mass. iii. 619. cerebellum, or third cerebral mass, iii. 619. optic nerves of fishes, iii. 764. Caseous Fishes, chiasma of the optic nenres in, iii. 769. Cartilaginous Fishes, chiasma of the optic nerves in, iii. 769. nerves, iii. 994. olfactory, iii. 699. 904. optic, iii. 995. third pair, iii. 995. fourth pair, iii. 995. sixth pair, iii. 996. seventh pair, iii. 996. eighth pair, iii. 996. ninth pair, iii. 722. 996. second pair of spinal nerves, iii. 996. sympathetic system, iii. 997. nervous system of Brancliiostoma, iii. 998. senses, iii. 998. smell, iii. 998; iv. 699. eye, iii. 999. sclerotic coat, iii. 999. memhrana argentea, iii. 999. iris, iii. 999. choroid, iii. 999. choroid gland, ii. 205 ; iii. 1000. optic nerve, iii. 1000. falciform ligament or marsupium, iii. 1000. aqueous humour, iii. 1001. crystalline lens, iii. 1001. vitreous humour, iii. 1001. muscles of the eyeball, iii. 1001. eyelids, iii. 95. 1002. auditory apparatus, ii. 536; iii. 1002. in Petromyzon, iii. 1(X)2. in Osseous" Fishes, iii. 1003. membranous vestibule, iii. 1003. sac of the otolithe, iii. 1003. otolithes, iii. 1004. semicircular canals, iii. 1004. auditory nerves, iii. 101. tracheal muscles, s. 22. arteries of the trachea, s. 262. bronchi, s. 262. the bronchi divide on no constant or regular plan, s. 26*. ultimate pulmonary tissue — lobules — historical bibliography, s. 264. minute anatomy of the lobule, s. 2,',6. 850 GENERAL INDEX. RESPIRATION, organs of— continued. ultimate air-cells of the lungs, — vesicula? s. cellulee aerere, s. Malpighianae; al- veoli pnlmonum of llossignol, s. 268. minute structure of the air-cells, s. 270. the epithelium of the air-passages and cells, s. 270. the elastic tissue of the air-cells, s. 272. vascular system of the lungs, s. 272. pulmonary artery, s. 273. veins, s. 274. bronchial system of vessels, s. 275. superior artery, s. 275. inferior artery, s. 275. bronchial veins, s. 275. anastomoses between the bronchial and pulmonary systems of vessels, s. 275. use of the nose in respiration, iii. 7-5. breathing by the nose and mouth compared, iii. 735. See also THORAX. II. Comparative anatomy, iv. 27ft. in Acalcphae, i. 44. in the Annelida, i. 170. in Arachnidans. in Echinodermata, ii. 40. in Cetacea, i. 579. in Crustacea,!. 177. in Entozoa, ii. 136. in Gasteropoda, ii. 389. in Marsupialia, iii. 309. in Mollusca, iii. 365. in Monotremata, iii. S9K in Myriapoda, iii. 549. in Pachydermata, iii. 872. in Pteropoda, iv. 173. in Quadrumana, iv. 209. in Reptiles, iv. 306. in Rotifera, iv. 413. in Ruminantia, s. 542. respiratory organs of birds, i. 341 ; iv. 276. 333. s. 276. of reptiles, s. 278. temporary branchiae of Amphibia, i. 98 ; s. 278. temporary external gills, s. 279. external gills of the Salmandrida?, s. 279. internal temporary branchiee of Amphibia, s. 280. air-bladder of Fishes, s. 281. lungs in Batrachia, s. 282. respiratory organs of Fishes, iii. 985 ; s. 286. mucous membrane of the branchiae, s. 287. vascular system of the branchiae, s. 287. minute circulation of the branchiae, s. 288. cartilage, or supporting system, of the branchiae, s. 289. III. Morbid anatomy of the lungs and air-passages, s. 291. inflammation of the bronchi : — «. acute bronchitis, s. 292. b. chronic bronchitis, s. '^92. c. plastic bronchitis, s. 292. collapse of the lungs, s. 292. asthma and hooping-cough, s. 292. dilatation of the bronchi : — uniform dilatation, s. 292. saccular dilatation, s. 292. bronchitic collapse of the lungs, s. 292. inflammation of the mucous membrane of the bronchi, s. 292. superficial suppuration, s. 292. pathological conditions of the broncho-pulmo- nary mucous membrane, s. 293. plastic or exudative bronchitis, s. 293. bronchial croup, s. 293. asthmatic affections, s. 293. forms of disease recognised by English pathologists, s. 293. inflammation of the vesicular tissue, s. 293. engorgement, s. 291 hepatisation, s. 293. grey hepatisation, s. 293. gangrene, s. 293. cancer of the lung, s. 293. phthisis, s. 293. seat of pulmonary tubercle, s. 293. nature of t-berculous matter, s. 293. mechanism of emphysema, s. 293. desquamation of the epithelium of the air-passages, s. £93. diseases of the larynx, iii. 114. See LAUYNX. RESPIRATION, function of, iv. 325. preliminary remarks, iv. 325—327. respiration of plants, i. 132 ; iv. 328. respiration of animals, i. 182 ; iv. 329. definition, iv. .'J29. conditions which regulate the energy of the function, iv. 329. RESPIRATION, function of — continued. respiratory membrane, iv. 331. gills or branchiae, iv. 331. tracheae, iv. 331. lungs, iv. 331. in birds, iv. 331. Man : apparatus for renewing the air in the lungs of the human species, iv. 333. the act of respiration a reflex nervous action, iii. 7211. the medulla oblongata the centre of respiratory movements, iii. 722 K. importance of the oxygen of the atmosphere to animal existence, iii. 31. relation of the circulation to, i. 675. relation which the pulse bears to the respiration, iv. 192. muscular movements in inspiration and expiration, iv. 334. measure of force of the muscular movements of inspiration and expiration, iv. 336. frequency of the respiratory muscular move- ments, iv. 338. motions of the glottis during, iii. 113. excitementof the respiratory muscles by the sudden application of cold to surface of body, iii. 589. relation of the degree of irritability to respiration, iii. 31. method for ascertaining the quantity of respiration in any given animal — the pneumatometer, iii. 31, 32. increase of respiration in running and leaping, iii. 479. state of the respiration during sleep, ii. 766. state of the, during the sleep of hibernating animals, ii. 767. 769. state of the, during the sleep of hibernating animals compared with that of the same ani- mals in a state of activity, ii. 769. quantity of air drawn into, and expelled from, the lungs, iv. 339. during quickened or forced respiration, iv. 340. changes upon the atmospheric air in respiration, iv. 342. animal matters exhaled from the lungs, iv. 314. per centage and quant' ty of carbonic acid gas in the expired air, iv. 345. effects of period of the day, iv. 346. digestion, iv. 346. fasting, iv. 347. alcohol, iv. 347. conditions of the mind, iv. 348. exercise, iv. 348. temperature, iv. 348. the seasons, iv. 349. barometric pressure, iv. 349. age. sex, and constitution of body, iv. 349. the respiratory movements upon the evolution of carbonic acid from the lungs, iv. 351. frequency of the respiratory move- ments, iv. 351. bulk of the air expelled, iv. 352. the stoppage of the respiratory move- ments for a time, iv. 352. quantity of oxygen gas absorbed by the lungs, iv. 354. differences, chemical and physical, between arte- rial and venous blood, iv. 356. free gases in the blood, iv. 358. theory of respiration, iv. 361. on the manner in which the air in the upper and that in the lower parts of the respiratory apparatus become intermixed, iv. 362. actions between the blood and the atmospheric air in the lungs, iv. 362. cause of the change of colour in the blood, iv. 365. effect of suspended respiration on the action of the heart, iii. 34. in various animals, iii. 35. power of bearing suspended respiration in hiber- nating animals, ii. 771. state of the respiration as a sign of approaching death, i. 801. Respiratory nerve, internal, iv. 754. Restiform bodies, iii. 678, 679. 682. function of the, iii. 722 K. Rete mucosum, or rete Malpighii, iii. 490; iv. 1333. testis, iv. 977. 979. Retepedes of Scopoli, i. 266. Reticulum, bonnet, or honeycomb, of the second stomach of Ruminantia, ii. 11. of the camel, s. 536. Retiform or reticular plexus, s. 712. Retina, peripheral expansion of nerves on the, iii. 596. central artery of the, i. 491 ; iii. 786. function of the, iv. 1439. abnormal vision arising from defective action of the retina or sensorium, iv. 1452. GENERAL INDEX. 851 Tieiinacula of Barry, s. 551. 560. Retractility of muscles, iii. 524. Retractor anguli oris muscle, iii. 566. Retrahfntes auriculam muscles, ii. 552. Revivitcence of hibernating animals, phenomenon of, ii. 774. causes of, ii. 774. Rhagades, or fissures, of the tongue, iv. 1156. Rheumatic arthritis genu, chronic, case of, iii. 58. of the shoulder-joint, chronic, iv. 584. fever, or inflammation of the joints, iii. 53. albumen in the sweat in a case of, iv. 93. gout, iv. 1526. Rheumatism, characters of the urine in, iv. 1293. chronic, or nodosity of the joints of the hand, ii. 518. of the hip (or chronic rheumatic arthritis), ii. 798. anatomical characters ii. 801. history of the disease, ii. 798. similar disease affecting other articula- tions. See ELBOW j HAND; KNEE; SHOULDER. causes of the disease, ii. 798. symptoms, ii. 799. history of two cases, ii. 799, 800. in the elbow-joint,' ii. 79. puerperal, of knee-joint, iii. 50, 51. in the larynx, iii. 123. Rhinoceros, anatomy of the, iii. 860. See PACHYDERMATA. structure of the horn, s. 478. pelvis of the, s. 156. stomach of the, s. 303. organs of voice of the, iv. 1493. urine of the, iv. 1280. Rhczocarpeae, vegetative system of, s. 245. macrospore of Pilularia, s. 245. prothallium, s. 245. embryo, s. 245. sporangia and spores, s. 246. Rhizodus, teeth of the, iii. 978. Rhizophaga, a tribe of Marsupialia, UL 267, et seq, genera of, iii. 2o/. Rhizophysa melon, i. 38. Rhizopoda, mode of reproduction of the, s. 6. ova of, s. [129.] Rhizosloma ca?rulea, i. 40. digestive organs of, i. 42. mode of progression of, iii. 433. ova of, s. [129.] Rhomboideus muscle, iii. 729 ; iv. 755. scapula? muscle, iv. 576. Rhynchophora, 9 tribe of the order Coleoptera, ii. S<>2. characters of the tribe, ii. 8fii. Rhynchosaurus, teeth of, iv. 890- Rhypophaga, a sub-tribe of Insecta, ii. 859. Rhythm of the heart, ii. 614. Rhytisma, reproductive system of, 8. 227. Rhyzomis of Sumatra, anatomy of the, iv. 371, et seq. Ribt, iv. 1024. classification of the ribs, iv. 1025. general characters, iv. 1025. special characters, iv. 1027. pleura costahs, iv. 2. cartilages of the, i. 249. See THORAX. Rice, properties of, as food, ii. 13. Rickets ( rachitis), i. 440 ; ». 189. causes of, i. 44<>. consequences, immediate and remote, L 440. symptoms, i. 440- cases of, in the foetus in utero, it 337. Ridge, canine, ii. 207. malar, ii. 208. mylo-hyoid, ii. 214. tu'rbinated, inferior and superior, of superior maxillary bones, ii. 208. Rigidity, a sign of actual death, i. 805. Rigor mortis, iii. 522. 524, 525. 721 N. Rim a glottidis, iii. 111. spasmodic closure of the, iii. 113. 124. laryngismus stridulus, iii. 113. 124. closure'of, in cases of erysipelas of larynx, iii. 118. Rima palpebrarum, iii. 79. Ring, abdominal, external, i. 4, 5. internal, i. 7. 12. crural, ii. 757. tympanic, ii. 544. umbilical, i. 9. Ringed snake (Col. natrix), nervous system of, iii. 620. Rings, cartilaginous, of the trachea, s. 261. of Crustacea, i. 753. Risorius Santorini muscle, iii. 566. Risus Sardonicus, cause of the, ii. 6. liii-inus, ducts of, iv. 425. hiatus of, ii. 560. process of, ii. 546. " Roaring" of the horse, causes of, iii. 123. Rocks, vitality of animals enclosed in, iii. 158. EODENTIA, an order of Mammiferous Vertebrata, iv. 368. bones of the cranium of various species, iv. 369. face, iv. 374. carpus, iv. 379. clavicle, iy. 380. RODENTIA — continued. bones of the femur, iv. 380. fibula, iv. 381. pelvis of the, s. 158. teeth of Rodentia, iv. 382. organs of digestion, iv. 385 ; s. 303. stomach, iv. 386. intestinal canal, iv. 389. liver, iv. 390. pancreas, iv. 390 ; 8. 97. spleen, iv. 390. t hymns gland, iv. 1096. lymphatic system, iv. 390 arterial system, iv. 390. venous system, iv. 391. nervous system, iv. 391. organs of the senses, iv. 392. organs and mode of locomotion of the, iii. 454. organs of generation, iv. 392. male organs, iv. 392. prostate gland, iv. 394. Cowper's glands, iv. 394. penis, iv. 395. Weberian organ in, iv. 1418. female organs, iv. 396. Rosenmiiller, organ of. See Parovarium, a. 593. Rotation of joints, i. 256. Rotator ia, or Rot if era. See ROTIFER A. Rotifer vulgaris, iv. 410. 412. habitat of the, iv. 407- Leeuwenhoek's description of the, iv. 397. stomach of the, s. 295. ROTIFERA, or ROTATORIA (wheel-animalcules), a class of Invertebrate Animals, i. 110 ; iii. 607 ; iv. 396. definition, iv. 396. discovery of the first Rotifer, iv. 397. localities inhabited by them, iv. 398. their power of recovering vitality after apparent perfect desiccation, iv. 398. Ehrenberg's division into families, iv. 400. cilia in, i. 607. tegumentary system, iv. 409. motory system, iv. 411. mode of progression, iii. 433. muscular and nervous systems, iii. 536. digestive system, iv. 411 ; s. 295. teeth, iv. 412. vascular and respiratory systems, iv. 413. nervous system and the organs of the senses, iii. 536. 607 ; iv. 414. reproductive system, ii. 410; iv. 414. mode of reproduction, s. [118.3 ovarian ova, s. [118.] spermatozoa of Annelida, iv. 498. Ehrenberg's summary of the general relations of the Rotifera, iv. 415. Round ligament of the liver, iii. 936. Round-worm (Ascaris lumbricoides), ii. 125. Rove-beetle (Creophilus maxillosus), ii. 863. Rugce of mucous membrane of the stomach, 8. 323. penniform, of uterus, s. 629. Rumen, or paunch of Ruminantia, 8. 302. structure of the rumen, s. 535. RUMINANTIA, an order of Mammalian Quadrupeds, 6. 506. essential characters of the order, s. 5D6. of the sub-orders — Camelida?, s. 506. Cervidae, s. 508. Antelopida?, s. 508. JEgosceridae, s. 508. Bovidae, s. 508. Osteology, s. 508. bones of the cranium, 8. 509. occipital bone, s. 509. parietal bone, s. 509. frontal bones, s. 509. sphenoid, s. 510. temporal bone, s. 511. bones of the face, s. 512. nasals, s. 512. intermaxillaries, s. 512. maxillaries, s. 513. lachrymals, s. 513. palatines, 8. 513. vomer and ossa spongiosa seu turbinata, 8. 515. interior maxilla or jaw-bone proper, s. 515. cranial peculiarities, 8. 516. horns, s. 516. vertebral column and bones of the trunk, s. 519. atlas in camels, 8. 520. axis or dentata, odontoid process of the, s. 520. dorsal vertebrae, s. 520. ribs, s. 520. pelvic bones, s. 156. 521. bones of the anterior extremity, 8. 521. scapula, s. 521. humerus, s. 521. bones of the fore-arm, 8. 521. carpal bones, s. 522. metacarpaU, g. 522. phalanges of the cloven foot, s. 522. 852 GENERAL INDEX. RUMINANTIA — continued. bones of the posterior extremity, s. 522. femur, s. 523. patella, s. 523. tibia, s. 523. bones of the tarsus, s. 523. metatarsals, s. 523. Myology of Ruminants, s. 523. panniculus carno»us, s. 523. musculus cutaneus faciei, s. 524. m. cutan. luimeri, s. 524. m. cutan. maximus, seu abdominis, s. 52-1. other muscles of the same category, s. j24. muscles of the head and trunk, s. 524. trapezius, s. 5'24. the broad muscle represented in the human subject by the splenius capitis and splenius cervicis, s. 525. trachelo-mastoideus, s. 525. great cpmplexus and digastricus colli, s. £25. transversalis cervicis, s. 525. scaleni muscles, s. 525. longus colli and recti, iii. 526. sterno-mastpideus or maxillaris, s. 525. rectus capitis anticus major, s. 526. hyoid apparatus, s. 526. muscles proper to the hyoid chain of bones, s. 527. sterno-hyoids and sterno-thyroids, s. 527. omo-hyoid, muscle analogous to, s. 5^7. stylo-hyoid, s. 527. ceratoido-lateralis, s. 527. masto-styloid, s. 527. mylo-hyoid, s. 527. genio-hyoids, s. 527. muscles connected with the hyoid apparatus of the giraffe, s. 527. muscles of the shoulder and fore-limb, s. 528. levator angulis scapulae, s. 528. rhomboideus major and minor, s. 528. serratus magnus or major, s. 528. minor, s. 528. latissimus dorsi, s. 528. pectoralis major, s. 528. ambibrachialis communis, s. 529. abductor longus brachii, or abd. brach. supe- rior, s. 529. supra-spinatus and infra-spinatus, s. 529. teres major, externus, minor, and internus, s. 529. coraco-brachialis, s. 529. biceps brachii, coraco-radialis, or flexor cubiti longus, s. 529. brachialis internus, or flexor cubiti longus, a. 529. extensor cubiti, s. 529. brevis, s. 529. brachialis externus, s. 529. anconeus internus, s. 5i:9. pro na tor teres, s. 529. extensor carpi radialis, s. 529. flexor carpi radialis, s. 530. extensores digitorum, longior et brevior, s. 530. abductor pollicis, muscle corresponding to, s. flexores carpi ulnaris externus et internus, s. 530. flexor digitorum sublimis et flex. dig. pro- fundus pertorans, s. 530. muscles of the haunch and hind-limb, s. 530. gluteus maximus, s. 530. tensor fasciae latae, s. 530. biceps femoris, or vastus longus, s. 530. iliacus internus, gluteus medius et minimis, and pyriformis, s. 530. obturator externus et internus, the gemelli, quadratus femoris, vasti, and adductores, s. 530. Integumentary system, s. 530. horns of, structure of, s. 478. the hump and cushion-like sole-pad of the drome- dary, s. 531. general character of the dermal envelope in Camelidae, s. 531. important changes co-existing with the shedding of the antlers in the solid-horned Ruminantia, s. 531. design of the cloven condition of the foot, s. 531. Digestive system, ii. 11. s. 532. buccal cavity, s. 532. teeth, s. 532. tongue, s. 533. papillae of the tongue, s. 533. muscles of the tongue, s. 534. vessels and nerves of the tongue, s. 535. salivary glands, iv. 433 ; s. 535. oesophagus, s. 535. stomach, ii. 11; s. 535. paunch, rumen, ingluvies, or panse, R. 302. 535. reticulum, bonnet, or water-bag, s. 536. psalterium, manyplies, omasus, or feuillet, s. 302. 537 RUMINANTIA, stomach — continued. reed, abomasus, or caillette, s. 302. 537. ruminating function, s. 537. concretions found in the paunch and reticulum, 8.538. the bezoar stones formed in the stomach of the chamois, s. 538. inverted action of the resophagus in returning the food from the stomach, iii. 760. intestinal tube, s. 539. intestinal glands, s. 539. liver, s. 540. pancreas, s. 541. spleen, s. 541. digestive organs of Ruminantia compared with those of the Carnivora, i. 479. larynx of the, iii. 103. organs of circulation, s. 541. of respiration, s. 542. nervous system, s. 542. brain, iii. 696. organ of vision, s. 543. of hearing, s. 543. of smell, s. 543. urinary organs, s. 543. reproductive system, s. 543. male organs, s. 543. Weberian organ in the, iv. 1419. female organs, s. 544. Rumination, or chewing the cud, ii. 11. causes of, ii. 11. power of rumination possessed by some individuals, s. 319. mode in which it is effected, s. 319, 320. Running, iii. 471. principles upon which walking and running differ, iii. forces employed in running, iii. 471. gravity and resistance, iii. 471. increase of the respiration and circulation in running, iii. 479. Rupture of the diaphragm, ii. 6. of the Fallopian tube, s. 620 of the heart, causes of, ii. 643. partial rupture of the heart, ii. 643. of tendons of the leg, iii. 132, of the urinary bladder, i. 400. of walls of uterus, s. 701. of veins, iv. 1399. Rutting season, iv. 473. development of the spermatozoa and testicles at, iv. 473. S. Sabulous matter in thepia mater, iii. 635. in the pineal gland, iii. 635. Sac, lachrymal, iii. 91 . finis cascus sacci lachrymalis, iii. 91. Sacculi, or cysts, of the urinary bladder, i. 393. Sacculus, ii. 569- laryngis of Hilton, iii. 112. size, form, and uses, iii. 112. rotundus, ii. 538. Sacral ganglia, s. 425. artery, middle, i. 197 ; ii. 828. lateral, ii. 830. origin and distribution, ii. 830. canal, s. 1)8,119. crest, s. 119. foramen, s. 118, 119. nerves, iv. 765 ; s. 641, note. anterior branches of, iv. 765. first, second, third, fourth, fifth, and sixth, iv. 765. posterior branches of, iv. 752. plexus of nerves, i. 181 ; iv. 765. veins, middle, iv. 1409. lateral, iv. 1409. Sacro-coccygeal joint, s. 122. motions of the articulation, s. 122. ankylosis of the, s. 183. ligament, anterior, s. 122. posterior, s. 122. muscles, anterior, s. 122. posterior, s. 122. Sacro-iliac articulations, i. 249 ; s. 122. cartilages, s. 122. inter-osseous ligaments, s. 123. ligament, superior, s. 123. anterior, s. 123. posterior, s. 123. deep, s. 123. superficial, s. 123. inferior, or short, superficial, g. 124. Hio-lumbar, s. 124. sacro-sciatic, great, s. 124. lesser, s. 124. lateral sacro-iliac, or posterior lateral iliac, of Sremmering, s. 125. movements of the joint, s. 125. ossification of the, s. 207. Sncro-lttmbalis muscle, i. 10. 372 ; s. 137. GENERAL INDEX. 853 Sacro-lumbar articulations, coalescence of the bones com- posing the, s. 207. Sacro-sciatic ligament, great, s. 124. lesser, s. 124 ossification of the, s. 207. notch, s. 127. Sacro-sjnnalis muscle, i. 10. Sacro-vertebral, or lumbo-sacral, ligament, s. 121. Sacrum, i. 367 ; 8. 118. its office, s. 118. base, s. 118. apex, s. 118. hollow of the sacrum, s. 127. promontory of the sacrum, s. 127. surface, anterior, or pelvic, s. 118. posterior, s. 118. lateral surfaces, s. 119. internal structure of sacrum, s. 119. development of the sacrum, s. 120. the sacrum in infancy, iii. 920. fractures of the sacrum, s. 208. deformity of the, s. 182. Sagittal suture, i. 737. Sahara, characters of the Tuaryks of, iv. 1357. Salamander (Salamandra terrestris), myology of the, iv. 285, et seq. American (Menopoma alleganiensis), cranial bones of the, i. 92. vertebra in the, i. 93, 94. teeth of the, i. 95. cutaneous secretion of the, L 102, eyelids of salamanders, iii. 95. ciliary motion in the larva of salamanders, i. 628, 6-29. external gills of salamanders, s. 279. Saline matters in organic substances, method of ascertain- ing the nature and proportion of, iii. 801. SALIVA, the, i. 12" ; iv. 415. method of analysing, iii. 811. quantity secreted during the day, iv. 415. physical qualities, iv 415. specific gravity, iv. 416. chemistry, iv. 416. i saliva of children, iv. 417. male and female saliva, iv. 417. general properties, iv. 418. saliva of animals, iv. 418. saliva in disease, iv. 419. salivary calculi, or tartar deposited on the teeth, iv. 419. ranula, iv. 420. hydrophobia, iv. 420. infection, iv. 420. syphilis, iv. 420. mercurial salivation, iv. 420. various kinds of diseased saliva analysed, iv. 421. fatty saliva , iv. 421. sweet saliva, iv. 421. bilious saliva, iv. 422. gelatinous s?'iva, iv. 422, milky saliva, iv. 422. urinary saliva, iv. 422. albumen in, in morbid states of the, iv, 93. adventitious fatty matter and fatty acid ex- creted in the, iv. 97. flow of saliva stimulated by mental emotion, iv. 466. uses of saliva, ii. 8. Salivary calculi, pljaliths, or tartar dep- sited on the teeth, iv. 83. 419. SALIVARY GLANDS, iv. 422. Normal anatomy, iv. 423. basement membrane of the, iii. 487. peculiarities of the salivary glands, iii. 498. parotid gland, iv. 423. position, form, and dimensions, iv. 423. duct of the parotid, or duct of Steno, iv. 423. arteries, veins, lymphatics, and nerves of, iv. 424. submaxillary gland, iv. 424. position, form, and dimensions, iv. 424. excretory canal, or \Vharton's duct, iv. 424. arteries, veins, nerves, and lymphatics, iv. 424. gublingual gland, iv. 424. position, form, andldimensions, iv. 425. ducts of the sublingual gland, iv. 425. arteries, veins, lymphatics, and nerves, iv. 425. subsidiary salivary glands, iv. 4^5. labial glands, iv. 426. buccal glands, iv. 4J6. molar glands, iv. 426. palatine glands, iv. 426. lingual glands, anterior, iv. 426. posterior, iv. 426. minute structure of the salivary glands, iv. 427. vascular supply, iv. 428. nervous supply, iv. 428. lymphatics, iv. 428. uses and relative importance of the salivary glands, ii. 8 ; iv. 428. saliva of mastication, iv. 429. of deglutition, iv. 429. See also DIGESTION. SALIVARY GLANDS — continued. Morbid anatomy, iv. 430. cynanche parotidea, or mumps, iv. 430. abscesses, iv. 430. encysted tumours, iv. 430. fibrous and carcinomatous degeneration, iv. 430. hypertrophy of the parotid, iv. 431. salivary fistula?, iv. 431. ranula, iv. 420. 431. morbid condition of the labial glands, iv. 431. Comparative anatomy, iv. 43L Entozoa, iv. 431. Echinodermata, iv. 431. Myriapoda, iv. 431. Insccta, iv. 431. Cirrhopoda, iv. 432. Pteropoda, iv. 432. Gasteropoda, ii. 388 ; iv. 432. Cephalopoda, i. 532 ; iv. 432. 1'isces, iii. 982 ; iv. 432. Reptiha, iv. 432. Aves, i. 316 ; iv. 432. Mammalia, iv. 433. Monotremata, iv. 433. Cetacea, iv. 433. Ruminantia, iv. 433 ; s. 535. Edentata, iv. 433. Carnivora, iv. 433. Solipeda, iv. 732. Salivary mucus, chemical characters of, iii. 482. Salivation, mercurial, analysis of the saliva of", iv. 421. spontaneous, analysis of the saliva of, iv. 421. Salmon, migration of the, iii. 13. its muscular power, iii. 13. its form considered with respect to its mode and organs of progression, iii. 437- its muscular power of springing into the air, ii. 62. pyloric caeca of the salmon, s. 93. Salmonida:, a family of Fishes, iii. 957. Salpa, a genus of Tunicata, iv. 1193, et $eq. characters of the genus, iv. 1193. Salpa cristata, mode of progression of the, iii. 434. Salpidce, a family of Tunicata, iv. 1192, et seq. characters of the family, iv. 1192. mode of reproduction of the, s. 23. Salpina, a genus of Rotifera, iv. 406. Salt, common, or chloride of sodium, office it subserves with reference to nutrition generally, ii. 15: s. 395. relish of all animals for, ii. 15. uses, ii. 15. effect of salt in facilitating digestion, s. 335. formation of a salt, iii. 151. Sallatoria, a group of Marsupialia, iii. 261, et seq. Salts of corn, s. 393. Sanctorian, or insensible, perspiration, iv. 841, 842. Sand, grains of, in the pia mater, iii. 635. in the pineal gland, iii. 677. Sandwich Islanders, physical characters of the, iv. 1362. Sanguification, process of, entirely or partially arrested during the sleep of hibernating animals, ii. 768. Sanguine temperament, iv. 936. Sanguineous excretions from the bladder, i. 401. Santorini, fissures of, or incisurte Santorini, ii. 553. muscle of, ii. 553. tubercles of, iii. 102. Saphena vein, i. 15. 148 ; ii. 238 j iv. 61. internal or long, iv. 1411. cutaneous and communicating branches, iv. 141 1. posterior, external, or short, iv. 1411. major, iii. 128. course of, ii. 351. minor, iii. 128. course of, ii 351. Saphcnous nerve, ii. 352 ; iv. 764. cutaneous tibial or reflected branch, iv. 764. accessory, iv. 763. external or communicans tibialis, iii. 130. internal, iii. 130. short, iv. 763. tibial, iv. 770. Saphenous trunks, iv. 1411. Sappho, ii. 686. Saprolegnia ferox, mode of reproduction of, s. 217. plants obtained by the germination of the zoosnores of Saprolegnia, producing reproductive organs of an entirely different character, s. 220. Sarcina ventriculi in the fluid of pyrosis, iv. 14t. Sarcolemma, or tunic of the elementary fibre of muscle, iii. 512. See MUSCLE. trichiniffi of sarcolemma, iii. 512, 513. Sarcoma, iv. 126. composition of, ir. 127. adipose, i. 63 ; iv. 129, :30. medullary, in the cranium, i. 746. of liver, iii. 193. of pancreas, s. 112. Sarcomatous polypi of the nose, iii. 740. Sarcophaga, a tribe of Marsupialia, iii. £58, et tea. genera of, iii. 258, 259. Sarcous elements, or primitive particles of muscle. See MUSCLE. tissue. See MUSCLE. GENERAL INDEX. Sardonic smile, cause of the, ii. 6. Sartorius muscle, s. 137. Satellite, nerve of the femoral artery, iv. 763. veins of brachial artery, iv. 1407. of gustatory nerve, iv. 1404. of the right subclavian artery, iv. 816. Satiety, effect of the lesion of the vagi upon the sensation of, Saturnia Carpini, ovum of, s. [113.] pavonia minor, nervous system of the larva of the, in. 611,612. Satyr iasis, iv. 985. '•• Sauria, an order of Reptilia, iv. 265, et seq. ciliary motion in, i! 631. pelvis of the, s. 170. dental system of the, iv. 889. tongue of, iv. 1147. pancreas of, s. 95. thymus gland of, iv. 1098. thyroid gland in, iv. 1108. muscles of, iii. 543. organs and mode of locomotion of the, iii. 448. Saw-fish, osseous spines of, i. 255. rostrum of, iii. 977. 980. Saw-flies, a family of Insecta, ii. 865. ravages of its larva in turnip-fields, ii. 865. 870. migration of, in myriads, iii. 16. organs of generation of the, ii. 992, 993. Scalce of cochlea, tympanic and vestibular, ii. 532. diameter of the, ii. 535. Scalenus anticus muscle, iii. 562 ; iv. 335. 817. posticus muscle, iii. 562; iv. 817. minimus (Scemmering) iv. 817. actions of the scaleni, iii. 562. Scales of fishes, iii. 972, 973; 8. 480. 501. colours of fish, iii. 972. argentine or metallic lustre of fish, iii. 972. teeth of scales, iii. 974. chemical composition, iii. 974. of reptiles, s. 480. Scallop, nervous system of the, iii. 604. Scalp, the, i. 747. atheromatous and meliceric deposits of the, iv. 97. Scansoria, a group of Marsupialia, iii. 261. Scansores, or climbing birds, characters of, i. 268. their mode of climbing and apparatus for prehension, iii. 451. pelvis of the, s. 169. Scaphoid bone of carpus, ii. 505 ; iv . 1506. articulations, ii. 505. of tarsus, ii. 340.343. structure and development, ii. 311. Scapula, or shoulder-bone, i. 359 ; ii. 156. borders, or costee, ii. 156. anterior, or axillary, ii. 156. posterior, or vertebral, ii. 156. superior, or cervical, ii. 156. spine of the, iv. 435. neck of the, iv. 573. development, ii. 159. connexions with the trunk, ii. 158. structure, ii. 157. surfaces of the bone, ii. 157. upright and oblique positions, uses of the, ii. 158. uses, iv. 437. displacement of the, iv. 435. fracture of the net k of the, iv. 601. Scapufa alatae of phthisical patients, ii. 157. Scapular artery, posterior, i. 367 ; iv. 436. 824. SCAPULAR REGION (descriptive and surgical anatomy of), iv. 433. definition, iv. 433. muscles, iv. 433. See ARM ; BACK; NECK. supra- and infra- spinal fossae, iv. 4,34. supra-spinal division of scapular region, iv. 434. trapezius muscle, iv. 434. supra-spinatus muscle, iv. 434. supra-scapular nerve, iv. 434. spine of the scapula, iv. 435. infra-spinal division of scapular region, iv. 435. trapezius muscle, iv. 435. latissimus dorsi muscles, iv. 435. infra-spinatus muscle, iv. 436. teres minor muscle, iv. 436. major, iv. 436. triangular compartment, iv. 436. posterior scapular artery, iv. 436. infra-spinal fossa, structures which occupy the, iv. 437. veins of the scapular region, iv. 437. lymphatics, iv. 437. uses of the scapula, iv. 437. furuncular inflammation of the scapular region, iv. 438. anthrax, iv. 438, chronic abscesses, iv. 438. fractures, iv. 438. ablation, iv. 438. Scapttlo-humcra\ articulation, iv. 572. Sec SHOULDER- JOINT (normal anatomy). Scaridium, a genus of llotifera, iv. 404. Scarlatina, syncope induced by, i. 797. Scarlatina anginosa, iii. 117. Scarf, or parrot- fishes, dental apparatus of, iii. 979 j iv. 871. 878. Scents, or odorous emanations. See SMELL. Schindylesis, form of articulation, i. 255 ; ii. 219 ; iii. 90. Schintoztmms reflexus, iv. 949. Schneiderian, or pituitary, membrane, iii. 726. 730. Schwann, white substance of, iv. 1140. Scuem'da:, a family of Fishes, iii. 956. et seq. Sciatic artery, ii. 250. nerve, iv. 439. great, iv. 767. origin and relations, iv. 767. lesser, iv. 766. branches, iv. 767. notch, great, s. 115. small, or obturator, s. 115. spines, deformity of the, s. 182. vein, iv. 1412. Scincidte, a family of Reptilia, iv. 265, et seq. Scincoid lizards, teeth of, iv. 891. Scincus officinalis, teeth of, iv. 891. Scirrhus cancer, characters of, i. 515; iv. 137. of mammae, iii. 255. bladder of scirrhus of mammae of Dr. Benedict. ' iii. 255. of the membranes of the urinary bladder, i. 402. of the muscular substance of the heart, ii. 637. of pancreas, s. 111. of thyroid gland, iv. 1116. Sciurus vulgaris, or squirrel, anatomy of the, iv. 730, et seq. spermatozoa of the, iv. 475. Sclerodermes, a family of Fishes, iii. P57, et seq- Sclerogenidce, a family of Fishes, iii. 956. Sclerotic coat or membrane, ii. 174; iii. 88. definition, ii. 174. inner and outer surfaces, ii. 174. thickness of the coat, ii. 174. tunica albuginea, or white of the eye, ii. 174. sclerotic coat in the lower animals, ii. 175. Scoliosis, iv. 949. Scolopax gallinula (snipe), nervous system of the, iii. 622. Scolopendra, a genus of Myriapoda, iii. 547, et seq. Sculopendra morsitans, nervous system of the, iii. 609. ' Scolvpendridce, a family of Myriapoda, iii. 547, et seq. Scolytus destructor, its ravages amongst elm trees, ii. 862. pygmaeus, its ravages amongst oak trees, ii. 8&2. Scomber scombrus, or mackarel, eyes of, iii. 10G2. thynnus (tunny), iii. 975. 994. Scomberidce, a family of Fishes, iii. 957. Scorbutus, effects of, on the action of the heart, i. 798. Scorpion-fiies (Panorpina), ii. 864. Panorpa communis (common scorpion-fly), ii. 864. Scorpions, alimentary canal of, i. 204. apparatus for secreting the irritating or poisonous fluid, eyesof,'i. 207, 208. generative system of, i. 210. nervous system of, i. 206. pectines of, i. 211. digestive organs of the, s. 299. muscular system of the, iii. 559. ova of scorpions, s. [115.] uses of scorpions in warm climates, iii. 27. See ARACHNIDA. Scratching birds ( Rasores), characters of, i. 268. Scrobiculus cordis, i. 2. 4. Scrofula affecting the ankle-joint, i. 161. anatomical characters, i. 161 . external characters, i. 162. ulcerations of the larynx caused by, iii. 119. Scrofulous diseases of bones, i. 449, 450. caries frcm a scrofulous cause, i. 450. caries of the spine, i. 451. progress of the disease, 1. 450. of the hip-joint,— morbus coxa?,— or strumous osteitis, ii. 789. of the kidney, iv. 257. of the ovary, s. 593. SCROTUM, iv. 438. skin of the scrotum, iv. 438. raphe, iv. 438. areolar tissue, iv. 438. septum scroti, iv. 438. dartos, iv. 438. vessels of the scrotum, iv. 439. nerves of the scrotum, iv. 439. contents of scrotum. See TESTICLE. passage of the testicle into the scrotum, iv. 982. morbid anatomy of the scrotum, iv. 1013. elephantiasis, iv. 1013. hypertrophy, iv. 1014. cancer scroti, or chimney-sweeper's cancer, i. 184 ; iv. 1014. melanosis scroti, iv. 1016. fibrous tumours, iv. 1016. Scurvy, state of the blood in, i. 425. land and sea scurvy, hemorrhage into the adipose tissue in, i. 62. Smttorancktato, ii. 379. See (TASTEROPODA. Scutigera, a genus of Myriapoda, iii. 546, et seq. GENERAL INDEX. Scutigcra livida, iii. 547. ' Scutigeridtr, a family of Myriapoda, iiL 516, el seq. cliaracters of the family, iii. 546. SctUipedes of Scopoli, i. 2b6. Scutula Wallrothii, si>ermagonia of, s. 230. pyciiidis of, s. 231. Scyllcea pelagica, nervous system of the, iii. 606. Scyphia, a family of Porifera, iv. 65. characters of the family, iv. 65. Scyphits of cochlea, ii. 552. Sea, phosphorescence of the, iii, 198, el seq. See LUMI- Noi'iNEss, AMMAL. physical effects produced by a particular display of the fuminousness of the sea, iii. 198. Sea-anemone, digestive organs of the, s. 29fi. Sea-gull (Larus cyanorhynchus), nervous system of the, iii. 622. Sea-jelly, or sea-nettle, i. 35. See ACALEPH^K. digestive organs of the, & 297. Sea-mouse, description of the, i. 617. ciliary motion in the, i. 618. Sea-scurry, condition of the blood after death from, i. 418. Sea-sicknt'sa, iv. 1174. Sea-urchin, ii. 30, et seq. See ECIIINODERMATA. ciliary motion in the, i. 615. fi!7. See CILIA. Sea-water, its absorption of the rays of light transmitted through it, and loss of transparency, iv. 1438. Seal, common (Phoca vitulina), organs of voice of the, iv. 1491. \Veberian organ in the, iv. 1418. grey ,Halichcerus gryphus), dentition of the, iv. 915. Seasonings of food, s. 395. See FOOD. Seasons, effect of the, on the quantity of carbonic acid gas in the expired air, iv. 349. on the production of animal heat, ii. 659. 681. Sebaceous glands, i. 216. of the nose, iii. 729. follicles of the vulva, s. 711. Sebum, i. 57. Second intercostal nerve, i. 217. Secreting canals, ii. 487, 488. SECRETION, i. 144; iv.439. definition, iv. 439. general observations, iv. 439. affinity between the functions of nutrition and se- cretion, iv. 440. animal and vegetable secretions compared, i. 135. organs of secretion, iv. 441. development of simple cells, iv. 441. excretory organs of animals, iv. 443. absorbent system, iv. 4J4. biliary apparatus in various animals, iv. 445. composition and development of secreting struc- tures, iv. 455. secreting structure of the testicle, iv. 977. mucous, lubricating the bladder, i. 386. sources of the demand for the secreting function, iv. 455. decay of animal structures, iv. 456. periodical decay, iv. 456. carbonic acid the first product of decay, iv. 456. removed from living bodies by the lungs and skin, iv. 456. water removed by the skin, iv. 456. nitrogen thrown off' by decaying bodies, iv. 4>ri. hydrocarbon of biliary secretion, iv. 453. nature of faecal matter, iv. 458. existence of the elements of secretions in the blood, iv. 459- metastasis of secretion, iv. 461. urine, iv. 461. biliary secretion, iv. 462. secretion of milk, iv. 461. 463. vicarious secretion of milk, iv. 463. menstrual flux, iv. 463. vicarious menstruation, iv. 464. influence of the nervous system on the secreting process, iv. 464. on the secretion of milk, iv. 464. by mental emotion, iv. 464. on the secretion of saliva, iv. 466. ga>tric juice, iv. 466. tears, iv. 4o6. changes in the state of nutrition arising from in- jured nerves, iv. 468- theories of the influence exerted by the nervous system on the nutritive and secretory functions, iv. 469. three ways in which secretions are probably separated from the body, iii. 503. proximate analysis of individual secretions, iii. 807. of the urine, iii. 807. of the blood, iii. 809. of milk, iii. 811. of bile, iii. 811. of saliva, iii. 812. Secretions of Carnivora, i. 481. See CARNIVORA. follicles producing peculiar secretions, i, 481, 482. of Polygastria, iv. 16. of Mammalia, iii. 235. Seeds, dormant vitality of, iii. 156. Seeing. See VISION. Segmentation of the ovum of animals, process of, s. [138.3 See OVUM. Selaginella, vegetative system of, s. 243. SeUa turcica, i. 726. SEMEN, ii. 457 ; iv. 472. definition, iv. 472. histiological elements of the semen, iv. 472. spermatozoa, iv. 472. liquor scminis, iv. 472. periodical development of the spermatozoa and testicles, iv. 473. rutting period, iv. 473. form, development, and history of spermatozoa, iv. 474; s. [137.] in Man, iv. 474. in Mammalia, iv. 475. in Aves, iv. 477- in Reptilia, iv. 480. in Pisces, iv. 483. in Mollusca, iv. 484. in Cephalopoda, iv. 485. in Gasteropoda, iv. 485. in Acephala, iv. 487. in Articulata, iv. 488. in Insecta, iv. 488. in Arachnida, iv. 490. in Myriapoda, iv. 492. in Crustacea, iv. 493. in Annelida, iv. 49ti. in Bryozoa, iv. 497. in Rotifera, iv. 498. in Radiata, iv. 498. in Echinodermata, iv. 498. in Acalephaz and Acanthozoa, iv. 499. in Infusoria, iv. 499. general conclusions respecting the morphology and development of spermatozoa, iv. 499. organisation of the spermatozoa, iv. 502. motions of the spermatozoa, iv. 502. chemical properties, ii. 458; iv. 505. circumstances on which the fecundating property of the seminal fluid depends, ii. 461. course of the ejaculated seminal fluid within the female organs, ii. 464. office of the Fallopian tube in the reception and trans- mission of the spermatic fluid, s. 607. power by which the semen reaches the oviduct, s. 607. is material contact of the semen and ovum necessary for fecundation ? ii. 462. mode ef discharge of the semen, ii. 458, 459. sources whence the semen is derived, ii. 457. vesicular seminales, ii. 458. See also VESICI'LE SEMI- NALES. physiological office of the semen, iv. 507. See also OVUM ; SEMEN. Setnibulb, or bulb, of the vagina, s. 712. Semicircular canals, ii. 530. 537. ampullae, ii. 530, 531. 537. horizontal, ii. 531. posterior, ii. 531. superior, ii. 531. development of the, ii. 558. function of the, ii. 569. 577. process, i. 733. taenia, iii. 675. Semidiuma, a section of Insects of the order Lepidoptera, ii. 867. characters of the section, ii. 867. Semilunar, or lunar, bone of carpus, ii. 505 ; iv. 1506. articulations, ii. 505. Semilunar cartilages of knee-joint (cartilagines falcatac, s. lunatae), iii. 45. nglion, ii. 298 ; s. 641, note. lds, iii. 84. in comparative anatomy, iii. 84. plica, iii. 80. or sigmoid valves of arteries, i. 223. valves of right ventricle, ii. 581. of left ventricle, ii. 584. Semimembranosus muscle, iv. 61 ; 8. 137. nerves for the, iv. 768. Seminal cercariae, ii. 112. See EHTOZOA. vesicles. See VESICI'LJE, SEMINALES. Semi-spinalis dorsi muscle, i. 372. Semi-tendinosus muscle, ii. 264 ; iv. 61 ; s. 137. nerve for, iv. 767. Semitic, or Syro- Arabian, group of languages, iv. 1347. characters of the Semitic nations, iv. 1347. complexion of the, iv. 1333. See VARIETIES OP MANKIND. Semnocebus, a genus of Quadrumana, iv. 215, ft seq. See QUAORUMANA. characters of the genus, iv. 215. Semnopithecus, a genus of Ouadrumana, iv. 195, et seq. See Qi APRI MANA. characters of the genus, iv. 195. Semnopithecus, digestive organs of the, s. 304. Senegal, characters of the inhabitants of, iv. 1352, 1353. gan fol 856 GENERAL INDEX. SENSATION, i. 144 ; Hi. 723 A ; iv. 508. definition, iv. 508. cause of, iii. 720 K. common and special sensations, iv. 509. objective and subjective sensations, iv. 510. reflex sensations, iv. 510. the optic thalami the centre of, iii. 722 M, 723 E. probable modus operandi of the brain in, iii. 711. See also NERVOUS SYSTEM, Physiology of; HEARING ; SMELL ; TASTE ; TOUCH ; VISION. animal and vegetable sensation compared, i. 137. apparatus of sensation in Crustacea, i. 7'~i2. in Annelida, i. 167. Senses, the, in infancy, i. 72. SENSIBILITY, iv. 510. definition, iv. 510. anatomical condition necessary for the development of greater or less sensibility, iv. 511. modifications of sensibility, iv. 511. degrees of nervous sensibility in various parts of the body, iii. 588. common sensibility, iii. 588. special sensibility, iii. 589. Sensitive nerves, iii. 720 H. plant, iv. 679. Sensorium, iv. 677, et seq. See SLEEP. Sensorium commune of Prochaska, iii. 720 K ; 722 A. . its functions and seat, iii. 721 E. Sepia, the Italian pigment so called, i. 536. hexapodia, electricity of the, ii. 82. Sepiadce, or cuttle-fishes, i. 521. characters of the family, i. 521. ova of the Sepia, s. [105], [106]. fossil shells of the, i. 520. Septum, or cuttle-bone, of cuttle-fish, i. 531. 546. Septa aponeurotic, i. 217- of the urinary bladder, i. 390. Septum nasi artery, i. 487. Septual branches of olfactory nerve, iii. 732. Septum, antero-posterior vertical, of the chest, iv. 1. cervico-thoracic, iii. 570. crurale, i. 13. lucidum, iii. 674, 675. layers of, iii. 674. ventricle of, iii. 674. median fibrous, of tongue, iv. 1124. mobile nasi, iii. 725, 726. nasal, i. 731. pectiniforme penis, iii. 913. of the perineum, artery of the, iii. 928. scroti, iv. 438. thoracico-cervical, iv. 816. transyersum, ii. 2. 538. ventriculorum, ii. 584. thickness of the, ii. 584. abnormal conditions of the, ii. 632* Sequestrum, or dead bone, i. 455, 456. Senfurm, or Indo-Chinese, group of languages, iv. 1347. characters of the Seriform nations, iv. 1350. Serolin, method of determining the presence of, in organic substances, iii. 798. in the composition of the blood, i.'411. Serous cavities, calcareous deposits in the, iv. 90. SEROUS AND SYNOVIAL MEMBRANES, iv. 511. organisation of, i. 51. elasticity of, ii. 60. white and yellow fibrous tissue, iv. 512. areolar tissue, iv. 513, 514. bursae, iv. 513. subcutaneous bursae, iv. 514. covering of the internal surface by a cell- growth, iv. 514. character of the cells, iv. 515. arrangement of the cells, iv. 515. subtendinous bursae, iv. 516. cartilage corpuscles, iv. 517. eynovial membranes, i. v51 ; iv. 518. epithelium of, iv. 519. vessels of, iv. 519. characters of, i. 251. relation to other articular structures, i. 251. analogy between serous and synovial membranes, i. 251. secretion of the unguen articulare, i. 253. serous membranes, iv. 522. description of these membranes, iv. 523. basement membrane, iv. 523. areolar tissue, iv. 524. subserous cellular tissue, iv. 524. vessels, iv. 524. lymphatics, iv. 525. nerves, iv. 525. choroid plexus, iv. 525. development of serous membranes, iv. 526. in the animal kingdom, iv. 526. in the human foetus, iv. 526. development by friction, iv. 526. physiology of the serous and synovial membranes, iv. 527. contrast of serous and synovial membranes, iv. 528. morbid anatomy of serous and synovial membranes, iv. 530. serous or dropsical effusions, iv. 530. physical and chemical properties, iv. 531. SEROUS AND SYNOVIAL MEMBRANES — continued. inflammatory or fibrinous effusions, iv. 532. characters of, iv. 533. first stage, iv. 533. second stage, iv. 533. effusion of plastic fluid, iv. 533. composition of this fluid, iv. 533. organisation of the effusion, iv. 535. tubercle, iv. 537. cancer, iv. 537. ossification, iv. 537- cysts, iv. 538. diseases of the subserous areolar tissue, iv. 538. of synovial membrane of the elbow-joint, loose cartilages, iv. 538. Serous membrane of the abdomen. See PERITONEUM. or peritoneal, lamina; of the bladder, i. 380. adventitious serous tissue, iv. 140. Scrpentidce, a family of Reptilia, iv. 265, et seq. Serpents, different modes of progression of, iii. 447. powers of climbing, swimming, and springing, iii. 447, 448. muscular system, iii. 542. eyelids, iii. 96. urine of, iv. 1281. Serrated membrane of Gordon, or ligamentum dentatum. iii. 6i5. office of the, iii. 646. Serratus magnus muscle, i. 5. 361 ; iv. 755. magnus anticus muscle, iv. 576. minor anticus muscle, i. 359. posticus inferior muscle, i. 371. superior, i. 371. Sertularia geniculata, a species of Polypifera, iv. 48. intimate organisation of, iv. 49. mode of growth, iv. 49. reproduction of, iv. 49, 50. mode of reproduction of, s. 19. luminousness of, iii. 198. Sertularidte, a family of Polypifera, iv. 20. 48. characters of the family, iv. 20. 48. genera, iv. 20. 48. ova of, s. [126.] Serum of the blood, i. 404. See BLOOD. analysis of the, iii. 483. cholesterine in-the, iv. 4fiO. effusion of serum into the sub-arachnoid and arachnoid cavities, iii. 717. and into the cellular tissue, i. 515. Sesamoid body, ii. 581. SESAMOID BONES, iv. 541. in human anatomy, iv. 541. structure, iv. 541. microscopic examination, iv. 542. development, iv. 542. disease and injury, iv. 542. other human sesamoi'd bones, iv. 542. comparative anatomy, iv. 542. other sesamoid bones in Solipedes and other Mam- malia, iv. 543. use of sesamoid bones, iv. 543. Sesamoid cartilages, iii. 727. Seta; of animalcules, iv. 6. SEVENTH PAIR OF NERVES, iv. 543. origin, iii. 684. connexions, iii. 684. facial and auditory nerves, iv. 543. auditory nerve, iii. 684 ; iv. 543. its apparent origin, iv. 543. course, iv. 544. facial nerve, or portio dura of the seventh pair, iii. 684 ; iv. 544. description, iv. 544. course, iv. 545. in the cranium, iv. 545. portio intermedia, iv. 545. in the temporal bone, iv. 545. connexion with the superficial petrosal nerve, iv. 545. branch from the facial to the membrane which closes the fenestra ovalis, iv. 546. filament to the stapedius muscle, iv. 546. chorda tympani, iv. 546. its connexion with the facial, iv. 546. connexion of the facial and vagus nerves, iv. 546. course external to the cranium, iv. 54fj. branches, iv. 546. posterior auricular nerve, iv. 546. digastric nerve, iv. 547. stylo-hyoid nerve, iv. 547. temporo-facial division, iv. 547. temporal branches, iv. 547. orbicular or supra-orbicular branches, iv. 547- infra-orbital filaments, iv. 547. buccal branches, iv. 547. cervico-facial division, iv. 548. supra-maxillary part, iv. 548. infra-maxillary part, iv. 548. minute anatomy of the seventh nerve, iv. 548. in the human subject, iv. 548. GENERAL INDEX. 857 SEVENTH PAID OF NERVES — continued. general results of examinations in comparative anatomy, iv. 550. phy-iology of the seventh nerve, iv. 551. facial nerve, iv. 551. effect of section of the facial nerve on the sense of smell, iv. 552. effect of division of the portio dura on the eye, iv. 653. influence of the facial nerve on the sense of taste, iv. 553. and on the sense of hearing, iv. 554. the facial nerve a nerve of motion, iv. 66f Sexes, structural differences of the, ii. 439. in infancy and youth, ii. 439. local changes attendant on puberty, ii. 439. in the female, ii. 439. in the male, ii. 439. See also GENERATION; OVARY; OVUM; UTERUS AND ITS APPKM>A(,KS. Sexual desire, ii. 441 not always entirely destroyed by castration, ii. 443. considered a mental emotion, iii. 722 Q. Gall's views of the connexion of the cerebellum with the sexual functions, iii. 722 S. Sexual malformation. See HERMAPHROUITISM. reproduction, ii. 434. See GENERATION; OVUM. Sharks, iii. 963, et seq., 981. Sheath, arterial, i. 221. brachial, anterior, L 217. posterior, i. 217. femoral, ii. 237 240. Sheep, anatomy of the, s. 508. cranium of, s. 512 514, 515. jaw-bone of, s. 515. hyoid bones of, s. 526. foot of, structure of, s. 531. intestine of, s. 539. pelvis of, s. 157. globular cyst developed in the brain of, ii. 118. variation in the breeds of sheep under various circum- stances, iv. 1312. milk of the, iii. So:?. analysis of, iii. 36-2. Shelahs, or mountaineers of Southern Morocco, characters of the, iv. 1357. Sin LI,, iv. 556. definition, iv. 556. general observations, iv. 557. shells of Mollusca, iv. 557- Echinodermata, iv. 556. Crustacea, iv. 569. periodical exuviation of the shell in Crus- tacea, iv. 571. shell-substance, membranous, of Dr. Carpenter, s. 489. Shells of Cephalopoda, i. 543. of Gasteropoda, ii. '579, et seq. See GASTEROPODA. of Tunicata, iv. 1193. design in the formation of shells, iii. 414. Shin, or crest of tibia, iii. 45. SHOI LOER-JOINT (normal anatomy), iv. 571. limits of region, iv. 571. elements of which this region is composed, iv. 571. supra-acromial twigs, iv. 571. deltoid muscle, iv. 571. scapulo-humeral articulation, iv. 572. 1. bones, iv. 573. See EXTREMITY. glenoid cavity, iv. 573. head of the humerus, iv. 573. the tuberosities, iv. 573. 2. structures which facilitate motion in the joint, iv. 573. a. glenoid ligament, iv. 573. b. cartilage of incrustation, iv. 573. 3. connecting media, iv. 574. capsular ligament, i. 359; iv. 574. synovial membrane, iv. 575. mechanical functions of the shoulder-joint, iv. 576. 1. flexion, iv. 576. 2. extension, iv. 576. 3. adduction, iv. 576. 4. abduction, iv. 576. 5. circumduction, iv. 577. 6. rotation, iv. 577. Sn'>iLr>;.R-joiNT (abnormal conditions of the), iv. 577. Section I. produced by Disease, iv. 577. acute arthritis of the shoulder, iv. 577. symptoms, iv. 577. anatomical characters of, iv. 577- chronic arthritis of the shoulder, iv. 577. simple chronic arthritis, iv. 578. symptoms, iv. 578. first, second, third, and fourth stages, iv. 578. cases, iv. 578, 579. anatomical characters of, iv. 580. cases, iv. 581,582. post-mortem examination, iv. 581, 582. anchylosis of the shoulder-joint, iv. 583. Sllpp. SHOULDER-JOINT — continued. chronic rheumatic arthritis of the shoulder-joint iv. 584. symptoms, iv. 584. diagnosis, iv. 585. anatomical characters, iv. 585. bones, iv. £86. cases, iv. 589, et seq. cases of partial luxation which have been pub- lished as the result of accident, but which arc considered to be specimens of chronic rheumatic disease, iv. 590—600. Section II. produced by Accident, iv. 600. Fractures, iv. 600. A. Fracture of the acromion process, iv. 600. mode of union, iv. 600. B. Fractures of the coracoid process, iv. 600. C. Fractures of the neck of the scapula, iv. 601. diagnosis, iv. 601. D. Fracture of the superior extremity of the humerus, iv. 601. 1. intra-capsular fracture of the humerus, iv. 601. dissection, iv. 602. 2. extra-capsular fracture through the lu- bercles, iv. 602. symptoms, iv. 603. case, iv. 603. post-mortem examination, iv. 603. diagnosis, iv. 603. 3. Fracture of the superior extremity of the humerus through the line of junction of the e.nphysis with the shaft of the bone, or close to this line, iv. 603. case, iv. 604. 4. Fracture of the surgical neck of the humerus below the tuberosities and original line of junction of the epiphy- sis with the shaft of the bone, iv. 605. Dislocations, iv. 605. 1. dislocation downwards and inwards into the axilla, iv. 606. symptoms', iv. 606. anatomical characters of, iv. 607- case, iv. 607. 2. dislocation forwards, iv. 609. 3. dislocation backwards of the head of the humerus on the dorsum of the scapula, the result of accident, iv. 611. symptoms, iv. 611. case, iv. 611. diagnosis between fractures of the superior extre- mity of the humerus and dislocations of the shoulder. joint, iv. 613. dislocation of the head of the humerus, accom- panied with fracture of the neck of the humerus, iv. 614. muscles, iv. 615. laceration of the tendon of the sub-scapularis mus- cle, iv. 615. cedematous swelling of the arm and forearm, ac- companying dislocation of the head of the hume. rus, iv G15. partial or general paralysis of the muscles of the arm as a consequence of dislocation of the head of the humerus, iv. 615. alterations of the nerves, iv. 616. artery, iv. 616. luxation of the head of the humerus complicated with lesion of the axillary artery, iv. 616. Section III. Congenital malformation of the shoulder- joint, iv. 617. general remarks, iv. 617. anatomical characters of congenital malformation of the shoulder-joint, with displacement of the head of the humerus inwards, iy. 618. case, iv. 618. anatomical examination of the joint, iv. 619. congenital malformation of the shoulder-joint, wi;h displacement of the head of the humerus on the dorsum of the scapula, iv. 619. case, iv. 620. Shrews, pelvis of, s. 164. S/irimps, muscles of, iii. 540. mode of progression of, iii. 436. Siah-P6s/i, a tribe of Northern India, physical characteris- tics of, iv. 1336. Sitimung. anatomy of the, iv. 199, et seq. Siamese Twins, ii. 317 ; iv. 970. portrait of one ef them, iv. 1323. Sidnyum, a genus of Tunicata, iv. lll'O, ct se/. characters of the genus, iv. 1190. Sighing, probable causes of, iii. 722 K. Sight. See VISION. near sight. See Myopia ; VISION. long sight. See Presbyopia ; VISION. Sight, organ of. See EYE. Sigillina, a genus of Tunicata, iv. 1189, el seq. characters of the genus, iv. 1189. SigUltna australis, iv. 1190. 3 K 858 GENERAL INDEX. Sigmoid cavity, great, ii. 66. 162. lesser, ii. 66. of the ulna, iv. 229. flexure, s. 362. 365. use of, s. 366. notch, ii. 214. valves, ii. 581. of arteries, i. 223. ^/'Mr-vessels, or salivary glands, of the larva; of insects, ii. 973. Silkworm moths (Bombycidael, ii. 867. SM-worms (Liparis mort), ii. 867. 874. Siluridce, a family of Fishes, iii. 957. Silurus electricus of Linnasus. See Malaptcrurus electri- cus. Simla (ape), a genus of Quadrumana, iv. 195, et seq. See QlJADRUMANA. characters of, iv. 195. Simla satyrus (ourang-oetan), anatomy of the, iv. 198, et troglodytes (chimpanzee), anatomy of the, iv. 198, el seq. pelvis of the, s. 151. Singing, art of, iv. 1485. Sinuositas mastpidea, s. sinus mammillaris, s. antrum mammillare, ii. 546. 559. Sinus or Sinuses : — of acetabulum, ii. 777. ampullaceus, ii. 530. 537. pocularis, iv. 151. development of, iv. 153. articularis (glenoid cavity of scapula), ii. 157- basilar, i. 7i7. of bones, i. 435. cavernous, iii. 633. cerebral, iv. 1374. circular, iii. 633 ; iv. 1451. commune, ii. 537. 569. function of the, ii. 569. of coronary vein, iv. 1415. great, ii. 597. common, of membraneous labyrinth, ii. 527. cranial, iv. 1387. of the dura mater, iii. 631. frontal, i. 729, 730 ; iii. 725. calculus of, iv. 82. in the walls of veins, iv. 1380. functions of these sinuses, iv. 1381. inferior falcis, iii. 631. * of internal jugular vein, iv. 1406. lateral, i. 732; iii. 632 ; iv. 1382 . longitudinal, inferior, iii. 629. 631. superior, iii. 631. anterior, iv. 1410. of frontal bone, i. 729. spinal, iii. 630. mammillaris, ii. 546. maxillary, ii. 209. occipital, iii. 629. 632. osteum, ii. 538. petrosal, superior, iii. 632. inferior, iii. 632 ; iv. 1406. pocularis, iv. 1252. prostatic, iv. 1246. See VESICUL.V PKOSTATICA. of Santorini. iii. 724. seu cavum, laryngis. See Rima glottidis. spheroidal, iii. 725. spinal, iii. 630. strait, iii. 631. transverse, iii. 632. torcular Herophili, iii. 631. of Valsalva, ii. 582. 584. of vena ports, iv. 1414. venosi of the human spleen, iv. 790. venosus, ii. 579. of occipital bone, i. 751. Siphonia, a family of Porifera, iv. '5. characters of the family, iv. 65. Siptncttlus, the, iii 537. muscles of the, iii. 537. Siren lacertina, muscles of the, iii. 543. vertebra? in the, i. 93, 94. S/Vcn-like monsteis, iv. 964. siren formation of pelvis, s. 208. Sirenonielia, iv. 964. Sivatherium, cranium of the, s. 518. SIXTH PAIR OF NERVES, iii. 684. 787 ; iv. 621. definition, iv. 621. visible origin of the nerve, iv. 621. branches, iv. 621. to sympathetic, iv. 621. to ophthalmic branch of the fifth, iv. 621. to the ciliary or lenticular ganglion, iv. 622. physiology of the sixth nerve, iv. 622. comparative anatomy, iv. 622. paralysis of the nerve from disease in the neighbour- hood, iv. 622. Size, in the organic and inorganic worlds compared, i. 1 18. Skates, muscles of the, iii. 543. SKELETON, i. 141 ; iii. 821; iv. 622. definition, iv. 622. SKELETON — continued. endo-skeleton, iii. 823. See OSSEOUS SYSTEM. skeleton of a crocodile, iii. 822. exo-skeleton, iii 844 See OSSKOI'S SYSTEM. law of unity in variety, iv. 622. Prop. I. Vertebras are unequal quantities, iv. 624. II. even the one vertebra is not of equal quan- tity in all individuals of the same species, iv. 625. III. all vertebrae contain a greater or less amount of known elemental pieces, iv. 625. IV. the dorsal vertebra of human anatomy is an artificial figure, iv. 625. V. the cervical vertebra developes the costal appendages also, iv. G'-d. VI. all the cervical vertebree develope costal appendages, iv. 6^'7, VII. the lumbar vertebra developes the costal appendage, iv. 627. VIII. all the lumbar vertebras develope costal appendages, iv. 628. IX. the sacral vertebra? develope costal appen- dages, iv. 628. X. the coccygeal vertebra? are deprived of their costal appendages, iv. 629. XI. the first seven thoracic costo-vertebral figures are whole or plus quantities, iv. 629. XII. the five asternal costo-vertebral forms are proportionals metamorphosed from five sternal costo-vertebral plus quantities, iv. 630. XIII. the five lumbar vertebra? are proportionals metamorphosed from five sternal costo- vertebral archetypes, iv. 630. XIV. the sacro-coccygeal series of vertebra? are proportionals degraded from, sternal costo-vertebral circles, iv. 631. XV. the seven cervical vertebras are propor- tionals degraded from seven sterno-costo- vertebral whcle quantities, iv. 631. XVI. the mf.mmalian spinal axis consists of a series of segmental quantities, whose only variety or specific ^distinction depends upon proportioning from whole thoracic quantities, iv. 631. XVII. unilormity of structure is a condition proper to the plus thoracic originals of the spinal axis of the mammalian body, iv. XVIII. every spinal segment which is lesser refers to every spinal segment which is greater ; and all lesser segments refer to that which is greatest, iv. 633. XIX. structural uniformity cannot characterise such spinal segments as are proportionally or quantitatively various, iv. 633. XX. specific variety is none other than propor- tional variety, iv. 633. XXI. the knowledge of the differential quantity between all spinal segments, renders them exactly uniform in idea, iv. 633. XXII. without knowing the full dimensions of whole or uniform quantities, we can never rightly understand the real charac. ter of lesser and special forms, and there- fore can never otherwise understand the law of formation, iv. 634. XX III. the mammalian cervix is not limited to the fixed number of seven cervical vertebra?, iv. 634. XXIV. the number of cervical vertebra? in the mammal cervix depends upon the num- ber of archetypal costo-vertebral figures which have suffered metamorphosis, iv. 635. XXV. the presence of cervical ribs subtracts from the number of cet vical vertebra?, and adds to the number of thoracic archetypes, iv. 636. XXVI. the length of the thorax depends upon the number of persistent co.^to-vertebral ar- chetypes, iv. 636. XXVII. the numerical length of the lumbar spinal region depends upon the number of ar- chetypes subjected to metamorphosis, iv. 637. XXVIII. the numerical length of the sacral and coccygeal scries is not fixed, and this is owing to the same fact of archetypes un- dergoing metamorphosis, iv. 637. XXIX. a comparison of the same numerical verte- bra 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, iv. 637. XXX. the anomaly is a link in the chain of form, iv. 638. XXXI. all the spinal segments of all classes and species of verti-bratcd animals are only as GENERAL INDEX. 859 SKELETON — continued. the variable proportionals of sterno- costo-vertebral archetypes, iv. 638. XXXII. the h void apparatus occurs opposite to the cervical spinal region, where we know costal quantity to be lost; the hyoid ap- paratus refers to the cervical vertebra, and consists of their ribs metamorphosed, iv. 640. XXXIII. the ventral apparatus occurs opposite to the lumbar spinal region, where we under- stand that costal quantity is lost; the ventral apparatus refers to the lumbar vertebrae, and consists of their ribs meta- morphosed, iv. 643. XXXIV. clavicles, coracoid bones, and ribs are iden- tical parts of the costo-vertebral whole quantities or archetypes, iv. (U4. XXXV. marsupial bones, pubic and ischiadic bones and ribs, are identical parts of the costo- vertebral whole quantities or archetypes, iv. 648. XXXVI. chevron bones and ribs are identical parts of the costo-vertebral whole quantities or archetypes, iv. 650. XXXVII. the sternal median line ranges from the maxilla to the pubic bones of the abstract archetypal skeletal fabric, iv. 6.51. XXXVIII. every fossil skeletal species of extinct animals, as well as every recent existing species of skeleton, is a form created of the archetypal skeleton, iv. 655. XXXIX. the cranio-facia! apparatus consists, like the thoracic apparatus, of variable propor- tionals of the stern o-costo-vertebral quan- tities, iv. 655. XL. the scapulary or fore-limbs of all the verte- brated animals are homologous to one another; the variety among these or- gans occurs by a metamorphosis or omis- sion of elementary quantity, iv. 661. XLI. the scapulary and pelvic members are ho- mologous, iv. 664. XLI I. the sterno-costo-verfebral quantity is a pro- portional of the dorso- ventral quantity, iv. 667. XLIII. the scapulary and pelvic pairs of limbs are proportional quantities metamorphosed from the dorso-ventral archetypes, iv. 669. XLIV. the cranio-facial apparatus of segments are proportionals of the dorso-ventral arche- types, iv. 673. XLV. the cranio-facial apparatus is the origin of the dorso-ventral archetypal series, and the caudal apparatus is its termination, iv. 673. XLVI. the uniform archetypal series undergoes a graduated metamorphosis of its quanti- ties for the production of all varieties of skeletal species, iv. 674. Skeleton of American tapir, iii. 863. of elephant, iii 858. of hippopotamus, iii. 862. of rhinoceros, iii. 864. Skin in infancy, i. 69. 72. in old age.'i. 80. basement membrane, iii. 4S8. 496. elasticity, ii. 59. peripheral expansion of nerves on the papilla? of the skin, iii. 596. rete mucosum, or rete Malpighii, iv 1333. pigment granules of the skin, iii. 496. differences in the colour of the skin in various races of mankind, iv. 1333. freckles, iv. 1335 excretions from the skin, ii. 149. perspiration or sweat, ii. 149. See SWEAT. cutaneous absorption, i. 31. See ABSORPTION. of the abdomen, i. S*. its appearance in women who have borne children i.3*. of arm, i. 216. of elbow, ii. 63. of the nose, iii. 729. softening of the skin, iv. 710. softening of appendaees of the skin, iv. 710. See TEGLMEXTARY ORGANS. Skull. See CRAXITM. Slave Coast, characters of the inhabitants of the, iv. 1352. SLEEP, iii. 151); iv. 677. definition, iv. 677. coma compared with sleep, iv. 677. necessity for sleep, iv. 677. encephalon, divisions of the, iv. 677. medulla oblongata, iv. 677. ganglia of sensation, iv. 677. hemispheric ganglia, iv. 677. the cerebellum, iv. 677. See NF.Rvnrs CTXTRES. difference between simple sleep and hibernation, iv. 678. cold productive of sleep and of hibernation, ii. 768. SLEEP — continued. hibernation, ii. 766. 777. sleep considered as the first stage of hibernation, ii. 765. augmentation of the irritability of the muscular system during sleep, ii. 766. state of the respiration during sleep, ii. 766. 775. state of the pulse during sleep, iv. 191. influence of sleep on the production of animal heat, ii. 670. phenomena presented by hibernating animals with regard to the production of heat, ii. 671. See HKAT, ANIMAL. sleep of plants, iv. 678. of leaves, iv. 678. periodicity of sleep, iv. 679. causes of sleep, iii. 723 B ; iv. 680. those which operate directly through the scnsorial organs themselves, iv. 680, 681. those whose action is indirect, being exerted pri- marily on the organic functions, iv. 681. phenomena of ordinary sleep, iv. 682. access of sleep, iv. 683. power of being aroused by impressions made upon the organs of sense, iv. 683. one of the chief distinctions between sleep and stupor, iv. 683. amount of sleep required by man, iv. 683. conditions by which it is affected, iv. 683. during infancy and childhood, iv. 685. during the adult period, iv. 685. as age advances, iv. 685. as affected by temperament, iv. 685. influence of habit, iv. 686. entire absence of sleep, — insomnia, iv. 686. habitual deficiency of sleep, iv. 686. serious consequences resulting from, iv. 686. degree to which sleep may be protracted, iv. 687. dreaming, iii. 723 B ; iv. 687. definition, iv. 687. chief feature of the state of sleep, iv. 687. reasoning processes and the imagination, iv. 687. incoherence and incongruousncss of the thoughts and images which pass through our minds in dreams, iv. 688. absence of control over the muscular system, iv. 688. incubus, or night-mare, iv. 688. direction of the current of thought often given by impressions on the organs of sense, iv. 688. rapidity with which trains of thought pass through the mind, iv. 689. analogous action of narcotics on the nervous sys- tem, iv. 690. Sleep-walking, or intense dreaming, iii. 723 B ; iv. 691. definition, iv. 691. character of the intellectual operations in somnam- bulism, iv. 691. state of somnambulism passing into that of ordinary dreaming, iv. 691. anecdotes, iv. 692. exaltation of the senses when in the somnambulistic state, iv. 693 readiness with which the train of thought may be guided, during somnambulism, by the prin- ciple of suggestion, iv. 694. hypnotic experiments, iv. 694. causes of somnambulism, iv. 695. natural, iv. 695. artificial, iv. 695. Mr. Braid's hypnotism, iv. 695, 696. 703. inhalation of anaesthetic agents, — chloroform, ether, &a, iv. 697. Sloth, or tardigrade, the, ii. 46—53. digestive organs of the, s. 302. pelvis of the, s. 161. organs of voice of the, iv. 1492. See EDENTATA. Slugs (I.imaces), organs and mode of progression of, iii. 44o. mode employed by gardeners to prevent slugs from destroying young and tender plants, iii. 445. slimy secretion of the, ii. 404. nervous system of the, iii. 605, 606. Small-pox of the foetus in utero, ii. 333. SMELL, iv. 697. in infancy, L 73. in old age, i. 80. definition, iv, 697. nature of odorous emanations, iv. 697. hypotheses, iv. 697. general structure of the organ of smell in man, iv. fi98. the olfactive organ in other air-breathing Verte- brata, iv. 699. correspondence of, with that man, iv. 699. nerve of smell, iv. 700. relation of the fifth pair of nerves to the sense of, ii. 309. section of the facial nerve indirectly affects the sense of smell, iv. 552. sense of smell exalted in the somnambulistic state, iv. flM. conditions of the exercise of the sense, iv. 70L 3K 2 860 GENERAL INDEX, SMELL — continued- purposes of the sense, iv. 701. the sense of smell, in the air-breathing Vertebrata, is, as it were, the sentinel of the respiratory organs, iv. 702. acuteness of the sense of smell among savage tribes, iv. 702. exaltation of the sense of smell when a deficiency of the other senses exists, iv. 702. information conveyed by the sense of smell, iv. 703. classification of odours, iv. 703. Smell, organ of. See NOSE. Snail, common (Helix pomatia), generative process of, ii. 397, 398. nuptial chain of marsh -snails, iii. .r66. organs and mode of progression, iii. 445. nervous system, iii. 605. power of snails of reproducing lost parts, ii. 402. slimy secretion, ii. 404. Sneer of contempt, muscles which cause the, iii. 729. Sneezing, iii. 735. influence of, on paralytic limbs, iii. 41. Snipe (Scolopax gallinula), nervous system of the, iii. 622. Snout of the hog, iii. 874. Snoiv, red, of the Arctic regions (Protococcus Kerme- sianus), ii. 117. Sodium, chloride of, or common salt, effect of, in facilitating digestion, s. 335. its alimentary value, s. 395. Si>ft commissure of the brain, iii. 702. SOFTENING AND INDURATION, iv. 703. definition, iv. 703. causes of softening and induration, iv. 704. softening of the brain, iii. 720 A ; iv. 706. white, iii. 720 A. red, iii. 720 A. cartilage, iv. 712. cellular tissue, iv. 712. heart, iv. 707. kidney, iv. 712. lungs, iv. 707. membranes : mucous, serous, and ar- ticular, iv. 708. digestive canal, s. 407. idiopathic, of the mucous membranes of the bladder, i. 399. muscular structure, iv. 712. osseous framework of the body, iv. 712. ovaries, iv. 712 prostate gland, iv. 712. skin, iv. 710. spinal cord, iii. 714; iv, 706. red, iii. 714. white, iii. 714. pancreas, s. 109. spleen, iv. 711. uterus, iv. 712. induration of the brain, iv. 706. cellular tissue, iv. 712. epididymis, iv. 712. fibrous tissue, iv. 713. heart, iv. 707. kidney, iv. 712. lungs, iv. 707. membranes : mucous, serous, and articular, iv. 710,711. ovaries, iv. 712. spinal cord, iv. 7C6. spleen, iv. 711. testicle, iv. 712. uterus, iv. 712. See ADVENTITIOUS PRODUCTS, — Growths. Solar, cffiliac, or epigastric, plexus of nerves, s. 428. Solar light, influence of, on animal luminousness, iii. 199. Sole-pad of the dromedary, structure of the, s. 531. Solea vulgaris, or sole, tongue of, iv. 1146. Soleus muscle, iii. 127. 132. 138. relations, iii. 139. Solids, sound transmitted by, ii. 566. animal progression on, iii. 440. See MOTION, ANIMAL. Solidungula, pelvis of the, s. 156. Weberian organ in the, iv. 1419. SoLIPEDA,iv.713. definition of the group, iv. 713. genus Equus, iv. 714. species : Equus caballus (the horse), iv. 714. Equus hemionus (the Dzigguetai), iv. Equus asinus (the ass), iv. 714. Equus zebra (the zebra), iv. 714. Equus quaccha (the quagga), iv. 714. Equus montanus (the onagga or dauw), iv. similarity of these species in their anatomy, iv. 714. Osteology, iv. 715. skull, iv. 715. spinal column, iv. 716. cervical vertebrae, iv. 716. atlas, iv. 716. axis, iv. 716. vertebras of the loins, iv. 718. SOLIPEDA, osteology — continued. sacrum, iv. 718. caudal vertebra?, iv. 718. • thorax, iv. 718. sternum, iv. 718. ribs, iv. 718. anterior extremity, iv. 718. scapula, iv. 718. humerus, iv. 718. forearm, iv. 718. carpus, iv. 718. metacarpal bones, iv. 719. posterior extremity, iv. 719- pelvis, iv. 719. os femoris, iv. 720. leg, iv. 720. tibia and fibula, ir. 720. tarsus and metatarsus, iv. 721. Myology, iv. 721. panniculus carnosus, iv. 721. proper muscles of the spine, iv. 722. spinalis dorsi et cervicis, iv. 722. longissimus dorsi, iv. 722. transversalis colli, iv. 722. sacro-lumbalis, iv. 722. cervicalis descendens, iv. 723. multifidus spinae, iv. 723. intransversarii colli, iv. 723. longus colli, iv. 723. quadiatus lumborum, iv. 723. muscles which raise or straighten the tail, iv. 723. which depress the tail, iv. 723. adapted to move the tail laterally, iv. 724. muscles derived from the spinal column which serve immediately for the movements of the cranium, iv. 724. muscles of the ribs and sternum, iv. 724. walls of the abdomen, iv. 725. anterior extremity, iv. 725. muscles of the shoulder, iv. 725. muscles inserted into the humerus, iv. 724. muscles of the fore-arm, iv. 725. flexors, iv. 725. extensors, iv. 725. supinators, iv. 725. pronators, absence of, iv. 725. muscles of the carpus and metacarpus, iv. 725. muscles of the hand, iv. 728. posterior extremity, iv. 729. muscles of the pelvis, iv. 729. muscles inserted into the os femoris, iv. 729. flexor muscles of the leg, iv. 729. extensor muscles of the thigh, iv. 729. muscles implanted into the foot, iv. 730. muscles implanted into the digit, iv. 730. muscles which act immediately upon the lower jaw, iv. 731. muscles of the os hyoides, iv. 731. muscles of the tongue, palate, and larynx, iv. 732. muscles of the face, iv. 732. alimentary apparatus, iv. 732. teeth, iv. 732. 867. salivary glands, iv. 732. parotid, iv. 732. submaxillary, iv. 732. sublingual, iv. 732. molar, iv. 732. pharynx, iv. 732. stomach and intestine, iv. 733; s. 303. liver, iv. 736. spleen, iv. 736. pancreas, iv. 737. circulatory apparatus, iv. 737. structure of the horse's foot, iv. 737. horny hoof, iv. 737. frog, iv. 738. sole, iv. 739. cartilages of the foot, iv. 740. soft parts of the foot, iv. 741. nervous system and organs of the senses, iv. 741. organs of generation, iv. 742. male, iv. 742. scrotum, iv. 742. penis, iv. 742. testicles, iv. 742. female, iv. 743. urinary bladder, iv. 743. orifice of the uterus, iv. 743. ovaria and Fallopian tubes, iv. 743. gravid uterus, iv. 743. urachus, iv. 743. hippomanes, iv. 744. mammary glands, iv. 744. wild and domesticated horses compared, iv. 1313. transmission of acquired instincts in horses, iv. 1313. GENERAL INDEX. 80 1 Somnambulism, phenomena of, iii. 723 B. ; iv. 691. definition, iv. 691. character of the intellectual operations in somnambu- lism, iv. 691. state of somnambulism passing into that of ordinary dreaming, iv. 691. anecdotes, iv. 692. exaltation of the senses when in the somnambulistic state, iv. 693. readiness with which the train of thought may be guided during somnambulism, by the principle of suggestion, iv. 694. hypnotic or mesmeric experiments, iv. 691. causes of somnambulism, iv. ixJ. natural, iv. 695. artificial, iv. 695. Mr. Braid's hypnotism, iv. 695, 69& 703. inhalation of anaesthetic agents, productive of a state resembling somnambulism, iv. 697. Soot. warts, and cancer scroti, iv. 1014. S-ircx, or shrew, pelvis of the, s. 161. or tufts, of some Algae, s. 215. Sorici,l0. Treviranus' and Baer's observations, ii. 430. propagation of, ii. 112. liquor seminis, iv. 472. periodical development of the spermatozoa and tes- ticles, iv. 473. rutting period, iv. 473. form, appearance, size, and history of spermatozoa, ii. 111.459; iv. 474. in man, iv. 474. in Mammalia, iv. 474. in Aves, iv. 477. in Reptilia, iv. 480. in Pisces, iv. 483. in Mollusca, iv. 484. in Cephalopoda, iv. 4S:.. in Gasteropoda, iv. 485. in Acephala, iv. 487. in Articulata, iv. 488. in Insecta, iv. 48«. in Arachnida, iv. 490. in Myriapoda, iv. 492. in Crustacea, iv. 493. in Annelida, iv. 496. in Brypzoa, iv. 497. in Rotifera, iv. 498. in Radiata, iv. 498. in Echinodermata, iv. 498. in Acalephae and Acanthozoa, iv. 499. general conclusions respecting the morphology and development of spermatozoa, iv. 499. organisation of the spermatozoa, iv. 5€2. motions of the spermatozoa, iv. 502. existence of spermatozoa in the fluid contents of tha cyst, in encysted hydrocele of the testicle, iv. 998 • chemical composition of spermatozoa, iv. 505. physiological office of the semen, ii. 112; iv. 507. action of the spermatozoa on the internal contents of the ovum, s. [137], [138]. See E \TOZO A ; SEME>. Sperocyclistus, a genus of Myriapoda, iii. 546, etteq. Speropceus, a genus of Myriapoda, iii. 546, et seq. Sperostreptus, a genus of Myriapoda, iii. 546, et seq. Sphacelus, a sign of actual death, i. 807. Sphteria, thecae and paraphyses of, s. '227. Spheerobolus, a genus of Myriapoda, iii. 546, et seq. Spheerotheria, a genus of Mvriapoda, iii. 546, et seq. Sphenoid bone, i. 726 ; iii. 725. alae raajores, i. 726,727. minores, i. 726. 728. articulations, L 728. body of the bone, i. 726. cells, sphenoidal, i. 726. definition, i. 726. development, i. 728. in intra-uterine life, i. 728. in extra-uterine life, i. 728. surfaces, anterior, i. 726. posterior, i. 726. under, i. 726. upper, i. 726. azygos process, i. 255. Sphenoidal cells, i. 726. Spheroidal sinuses, iii. 725. suture, i. 737. ventricle, iii. 674. Spheno-maxillary nerve, ii. 283. S^heno-ocdpital bone, i. 733. Spheno-palatine artery, i. 490; iii. 733. foramen, ii. 211. nerves, ii. 284. Spheno-parietal suture, i. 737. Spheno-temporal suture, i. 737. Spherical aberration of light, iv. 1438. 1441. Sphincter ani cutaneus (vel coccygeo-an:d, sphincter ex- ternus, constrictor ani), i. 176; s. 309. use, i. 176. internus vel orbicularis, i. 176 ; s. 138. 369. action, i. 177. remarks on the nervous action of the sphincteres am, iii. 721 K. oris muscle, ii.223. vagina; muscle, s. 138. Sphinges, or hawk-moths (Crepuscularia), ii. 866. Sphinx atropos, or death's-head moth, its attacks on bee- hives, iii. 21. elephant (Deilephila elpenor), ii. 867. ligustri, ii. 875. larva of, ii. 875. 877. Spices, employment of, in diet, ii. 15. effects of, on various parts of the body, it 15. Spicula of sponges. See PORIFERA. Spider, its mode of taking its prey. iii. 8, 9. organs and mode of locomotion, iii. 444. muscular system, iii. 539. nervous system, iii. 609. ova of spiders, s. [1 14]. 3K 3 862 GENERAL INDEX. Spider — continued. instinct of Cteniza caementariain constructing its sub- terranean abode, iii. 10. and of the water-spider in the construction of her habitation, iii. 9. web of spiders, i. 209. See ARACHNIDA ; Araneidce. Spfeot of Iteil, iii. 691,692. Snina bifida, iii. 713; iv. <»57. totalis, iv. 957. partialis, iv. 957. of the foetus in utero, ii. ?.2I. tuberculi majoris, ii. 159. minoris, ii. 159. ventosa, osteosarcoma, osteosteatoma, enchondroma, iv. 132—134. definition, ii. 516. origin of the disease, ii. 516. description of the disease, i. 457. progress of the disease, i. 457. in children, i. 457. in adults, i. 457. treatment, i. 457. of the bones of the hand, remarkable case of, ii. 514,515. SPINAL Accessory Nerve, i. 731 ; iii. 707. 835 ; iv. 745. 820. origin and course, iv. 745. branch, external, iii. 885 ; iv. 748. internal, iv. 748. connexion of the spinal accessory and vagus, iii. 890. comparative anatomy of the spinal accessory nerve, iv. 748. physiology of the spinal accessory, iv. 749. Spinal apoplexy, cause of, iii. 713. arteries, i. 731. anterior, iii. 656. 704. posterior, iii. 657. 704. bulb, ii. 270. canal, s. 119. column. See Vertebral column. Spinal column, (in comparative anatomy), iii. 823. elements of a vertebra, iii. 824. autogenous parts, iii. 824. exogenous parts, iii. 824. abnormal anatomy, iv. 1036. curvature of the spine, lateral and angular, iv. 1036. congenital defective development of the spinal column, iv. 965. Spinal cord, ii. 270 ; iii. 650. position in the adult, iii. 650. in the foetus, iii. 651. shape, iii. 651. bulk, iii. 651. length and circumference, iii. 651. fissures, iii. 652. anterior, iii. 652. posterior, iii. 652. grey commissure, iii. 652. white commissure, iii. 652. internal structure as shown by transverse sections, iii. 653. antero -lateral columns, iii. 6~->3, 654. posterior columns, iii. 653, 654. arrangement of the grey matter in the spinal cord, iii. 653. conclusions, iii. 654. is there a cemral canal in the spinal cord? iii. 655. blood-vessels of the spinal cord, iii. 656. median artery, anterior, iii. 656. spinal arteries, anterior, iii. 656. posterior, iii. 657. veins of the spinal cord, iii. 657. spinal nerves, origin, anterior and posterior roots, ganglion, iii. 657. sub-occipital nerve, iii. 658. characters proper to the nerves of particular re- gions, iii. 658. cervical nerves, iii. 658. dorsal nerves, iii. 658. lumbar nerves, cauda equina, iii. 658. relations of the roots of the nerves to the columns ot the cord and to the grey matter, as deter- mined by dissection, iii. 659. as determined by physiology, iii. 660. membranes of spinal cord. See NERVOUS CENTRES. sketch of the microscopic anatomy of the spinal cord, iii. 707. of Marsupialia, iii. 295. of fishes, iii. 615. abnormal anatomy of the spinal cord and its mem- branes, iii. 712. cord, iii. 7 13. absence of the cord, iii. 713. partial absence, iii. 714. excessive congenital development, iii. 714. hypertrophy, iii. 714. atrophy, iii. 714. induration, iii. 714 ; iv. 706. softening, iii. 7 14 ; iv. 7 6. red softening, iii. 7J4. white softening, iii. 714. Spinal cord — continued. suppuration, iii. 715. effusion of blood, iii. 715. tubercle, iii. 715. cancer, iii. 715. membranes, iii. 712. affections of the dura mater, iii. 713. See also SPINE. of the arachnoid, iii. 7 13. of the pia mater, iii. 713. functions of the spinal cord, iii. 720 X. facts in the physiological history of the spinal cord, iii. 720 X. physical nervous actions of the cord, iii. 721 A. sympathetic actions, iii. 721 A. Whytt's views, iii. 721 B. summary of Prochaska's work, iii. 721 C. facts which demonstrate a power in the cord of ex. citing movements in parts which receive nerves from it, by changes occurring in its substance, iii . 721 G. stimulus applied to the cord, iii. 721 G. substances exerting a peculiar influence upon the spinal cord, iii. 721 G. strychnine, iii. 721 G. opium, iii. 721 H. cold, iii. 721 H. ether, iii. 721 H. sensitive impressions may be reflected by the cord, iii. 721 H. enumeration of the functions of the body with which the spinal cord is immediately con- cerned, iii. 721 I. Dr. Marshall Hall's doctrine, iii. 721 I. tone of the muscular system, iii. 721 M. conclusions, iii. 721 N. of the office of the columns of the cord, iii. 721 O. antero-lateral columns, iii. 721 O. posterior columns, iii. 721 O. manner in which the posterior columns may contribute to the exercise of the lo- comotive functions, iii. 721 Q. middle or respiratory column of Sir C. Bell, iii. 721 R. influence of the spinal cord upon the organic func- tions, iii. 721 R. on the kidneys, iii. 721 S. erection of the penis, iii. 721 T. mechanism of the functions of the cord, iii. 721 T. Dr. Marshall Hall's hypothesis of an excito- motory system of nerves and true spinal cord, iii. 721 U. hypothesis of Mu'ller and others, that every nerve-fibre in the body is continued into the brain, iii. 722 B. Todd and Bowman's hypothesis that .all the nerves are implanted in the grey matter of the segments with which they are connected, and do not pass beyond, iii. 722 B. Spinal ganglia, s. 437. marrow. See Spinal Cord. SPINAL Nerves, i. 3(i8 ; iii. 657 ; iv. 750 ; s. 641. posterior branch of the first cervical or sub-occipital nerve, iv. 750. of the second cervical nerve, iv. 750. of the third cervical, iv. 751. horizontal branch, iv. 751. posterior root of the fourth cervical nerve, iv. 751. posterior branches of the fifth, sixth, seventh, and eighth cervical nerves, iv. 751. posterior branches of the dorsal (thoracic) nerves, iv. 751. external or muscular branches of the eight superior, iv. 751. the internal branches, iv. 751. external branches of the four inferior, iv. 751. internal branches of the four inferior, iv. 751. posterior branches of the lumbar nerves, iv. 752. external brandies, iv. 752. internal branches, iv. 752. posterior branches of the sacral nerves, iv. 752. anterior branches of the spinal nerves, iv. 752. branch of the first cervical nerve, iv. 752. of the second cervical nerve, iv. 752. of the third cervical nerve, iv. 752. of the fourth cervical nerve, iv. 752. cervical plexus, iv. 752. superficial's colli, iv. 753. ascending branch, iv. 753. descending branch, iv. 753. auricularis magnus, iv. 753. superficial branch, iv. 753. deep branch, iv. 753. occipitalis minor, iv. 753. supra-clavicular and acromial nerves, iv. 753. acromial nerves, iv 753. communicating branches, iv. 753 internal descending cervical, iv. 753. GENERAL INDEX. 803 SPINAL nerves — continued. phrenic nerve, iv. 754. right and left phrenic, iv. 754. anterior branches of the four inferior cervical and first dorsal nerves, iv. 7-~4. brachi.il plexus (axillary), iv. 754. nerve for the rhombouieus, iv. 755. to the serratus magnus, iv. 7J5. for the subclavius, iv. 755. supra-scapular nerve, iv. 755. suhscapular nerves, iv. 755. nerves for the suoscapularis, iv. 755. internal cutaneous, iv. 755. external terminal branch, iv. 755. internal branch, iv. 756. cutaneous nerve of Wrisberg (the accessory nerve of the internal cutaneous), iv. 756. external cutaneous, iv 756. branches to the biceps, iv. 756. branches for the brachialis anticus, iv. 756. median nerve, iv. 756. muscular branches, iv. 756. anterior interosseous nerve, iv. 756. palmar cutaneous branch, iv. 757. terminal digital branches of the median, iv. 757. first digital nerve, iv. 757. second digit il nerve, iv. 757. third digit..! nerve, iv. 757- fourth digital nerve, iv. 7a7. fifth digital nerve, iv. 757. ulnar nerve, iv. 757. dorsal branch, iv. 758. superficial external, iv. 753. deep branch, iv. 758. musculo-spinal nerve (radial), iv. 758. internal cutaneous, iv. 759. branch for the internal head of the triceps, iv. 759. for the outer head of the triceps and aiico- naeus, iv. 759. external cutaneous branch, iv. 759. anterior terminal branch, iv. 759. internal branch, iv. 759. deep terminal branch, iv. 759. circumflex nerve (axillary), iv. 759. anterior branches of the dorsal (intercostal) nerves, iv. 760. cutaneous branches, iv. 760. intercostal branches, iv. 7(0. special characters of the intercostal nerves, iv. 760. anterior branches of the lumbar nerves, iv. 761. the lumbar or lumbo-abdominal plexus, iv. 761. upper musculo-cutaneous, iv. 761. lower musculo-cutaneous, iv. 762. geui to- crural nerve, iv. 762. crural nerve (femoral), iv. 762. internal cutaneous nerve, iv. 762. accessory saphaenus nerve, iv. 703. middle cutaneous nerve, iv. 763. r.erve to the femoral vessels, iv. 763. branch for the vastus internus, iv. 763. for the'cruraeus, iv. 763. for the rectus, iv. 763. for the vastus externus, iv. 763. saphaenus nerve, iv. 764. obturator nerve, iv. 764. anterior branches of the sacral nerves, iv. 765. sacral plexus, iv. 765. nerve for the obturator internus, iv. 766. internal pudic nerve, iv. 766. superior branch (dorsal nerve) of the penis, iv. 766. inferior branch (perinaeal), iv. 766. pudic nerve, iv. 706. superior glutaeal r.erve, iv. 766. interior glutaeal nerve (lesser sciatic), iv. 766. cutaneous branch to the back of the thigh and upper part of the leg, iv. 767. nerve for the pyriformis, iv. 767. nerves for the gemelli and quadratus femoris, iv. 767. great sciatic nerve, iv. 767. nerve for the semi-tendinosus, iv. 767- semi-mem tranosus, iv. 761. peroneal nerve (external popliteal), iv. 768. peroneal cutaneous, iv. 768. peroneal saphaenus, iv. 768. superior external articular, iv. 768. inferior external articular, iv. 768. anterior tibial nerve, iv. 768. musculo-cutaneous nerve, iv. 769. tibial nerve, iv. 769. muscular branches, iv. 769. terminal branches, iv. 77". internal plantar nerve, iv. 770. external plantar nerve, iv. 771. Spinal sinuses, iii. 630. longitudinal, iii. 630. tumours, iii. 713. veins, iv. 1387. 1406. 1409. superficial or extra-spinal veins, iv. 1100, 1410. Spinal veins — continued. deep or intra spinal veins, iv. 1409, 1410. posterior deep spinal veins, iv. 1410. Sptnalis, or semi-spinalis, muscle, i. 373. Sfunnlis dorsi muscle, i. 372. Spinax acanthias, or dog-fish, sexual organs of the female. iii. 1009. Spine, caries of the. i. 451. description of, i. 451. symptoms of, i. 451, 452. ulceration of the intervertebral cartilages, i, 452. iliac, posterior superior, s. 1 15. internal crucial, i. 731. external crucial, i. 732. of the ischium, s. 115. nasal posterior, ii. 210. of thepubis, 8. 115. scapula, ii. 157; iv. 435. tibia, ii. 168; iii. 45. Spines, cuticular, of fishes, iii. 975. of the Echinus, iii. 440. osseous of sawfish, i. 255. of the porcupine, hedgehog, and Echidna, s. 478. 498. Spinnarett of spiders, i. 209. Spinous processes, i. 727, 728. posterior superior, s. 114. anterior superior, s. 114. anterior inferior, s. 115. Spinous process of ilium, anterior superior, ii. 500. posterior inferior, s. 115., of sacrum, s. 118. Spiracles of insects, ii. 982. See INSECTA. thoracic spiracle of blow-fly (Musca vomitoru), iv. 1504. Spiral groove of humerus, i. 217. Spirugyra setiformis, mode of reproduction of, s. 219. Spiroineler of Dr. Hutchinson. iv. 341. 1068. to determine the volume of air in the spirometer , iv. 1070. to -correct the respired volume for temperature, ir. 1070. Spiroptera hominis, a species of Entoroa hominis, ii. 123, 124. Spirnstomum, or snail animalcule, iv. 13. Spirulidts, fossils of the, i. 520. Splanchnic nerve, s. 641, note. left, ii. 4. lesser, ii. 4. right, ii. 4. SPLEEN, iv. 771. in infancy, i. 68. situation and form, iv. 771. outer surface, iv. 771. inner surface, iv. 771. upper extremity, iv. 771. lower extremity, iv. 771. anterior border, iv. 771. posterior border, iv. 771. varieties of the spleen, iv. 771. size and weight, iv. 771. consistence, iv. 772. structure, ii. 20; iv. 772. 839. 1. serous membrane, iv. 772. 2. fibrous coat (tunica nbrosa, albuginea, sive propria), iv. 772. 3. trabecular tissue (trabeculae lienis, balks, or joints, of the spleen), iv. 773. 4. splenic corpuscles, or Malpighian corpuscles of the spleen, iv. 775. minute structure, iv. 777. 5. the red spleen substance, the spleen-pulp, the parenchyma of the spleen (substantia rubra, pulposa, parenchyma lienis), iv. 780. cells of the spleen-pulp, iv. 780. blood effused in the spleen-pulp and me- tamorphoses of the blood-globules in the same, iv. 781. cells in Mammalia, iv. 783. in Aves, iv. 783. in Reptilia, iv. 783. in Pisces, iv. 784. 6. blood-vessels of the spleen, iv. 787. splenic artery (arteria linealis), iv. 787. splenic vein, iv. 788. 7. lymphatics of the spleen, iii. 229 ; iv. 793. 8. nerves of the spleen, iv. 794. 9. physiological and pathological properties of the spleen, iv. 795. functions of the spleen, iv. 415. 796. morbid anatomy, iv. 800. enlargement, iv. 800. atrophy, iv. 801. inflammation, iv. 801. softening and induration, iv. 711. Spleen of Birds, i. 327. See AVES. of Fishes, iii. 983. of Rodentia, iv. 390. of Mar*upialia, iil. 305. of Solipeda, iv. 732. of Ruminantia, s. 541. Splen. See SPLEEN. 3K 4 864 GENERAL INDEX. Splcnfc artery, i. lf'5; IT. 7S7; s. 32G. extremity of stomach, s. 308. omentum, iii. 941. plexus of nerves, s. 420. vein, iv. 788. 1414; s. 381. Splenico phrenic fold, i. 14. Splenius capitis muscle, i. 371 . colli or cervicis, i. 371. Spondyhts, i. 112. mges, iv. 64. See PORIFERA. mgia, a family of Porifera, i. 612; iv> 65. characters of the family, iv. 65. cilia, probability of, in, i. 612. "faecal orifices" of, i. 612. ciliary motion of the ova of, i. 613. composition of the texture of Spongia officmalis, 111 . 601 . nervous and muscular globules of which its texture is composed, iii. 601. alleged luminousness of, iii. 198. mode of reproduction of the, s. 6. ova of, s. [129]. Spongilla, a family of Porifera, iv. 65. characters of the family, iv. 65. Spongy portion of urethra, iii. 925. Spontaneous generation of animals, ii. 420. SeeGENEUATioN. Sporangia in vegetable reproduction. See REPRODUCTION, VEGETABLE. Spores, vegetable reproduction by, s. 233, et seq. See RE- PRODUCTION, VEGETABLE. Sponferous generation of Polygastria, iv. 16. Sporophylla of Equisetaceae, s. 242. Spouting apparatus in whales, i. 580. Baron Cuvier's description of, i. 581. Spring in the latitude of England, why a more dangerous season than Autumn, ii. 681. Springing-beetles, ii. 861. Spur of the ornithorhynchus, iii. 406. use of the, iii. 40G, 4<)7. Squalus cornnbicus, progressive development of the ve- sicles of the testis of, iv. 453. Squamella, a genus of Rotifera, iv. 406. Squamipennes, a family of Fishes, iii. 956. Squamous portion of the temporal bone, i, 734. Squamuus suture, i. 737. Squirrel (Sciurus), anatomy of the, iv. 370, et seq, spermatozoa of the squirrel, iv. 475. Squirrel, flying (Pteromys volitans), anatomy of the, iv. 368, et seq. Stag, effect of castration on the growth of the horns of the, ii 718. Stag-beetle (Lucanus cervus), ii. 801, note. Standing, effect of long-continued, on the veins of the leg, iii. 128. Stapedius muscle, ii. 549. functions of the, ii. 574. Stapelia, or carrion-flower, iv. 700. Stapes, or stirrup-bone, ii. 547, 548. ligamentum annulare baseos stapidis, ii. 548. development, ii. 560. musrles of the, ii. 549. functions of the muscle, ii. 574. functions of the stapes, ii. 573. abnormal conditions, ii. 561. Staphylinidts, ii. 859. Stnpfii/loma pellucidum, ii. 177. Star-fish, ii. 31, et seq.;\i\. 537; iv.850. See ECHINODERMATA. muscles of the, iii. 537. nervous system of the, iii. 602. Starch of corn, s. 393. Starvation, colliquative diarrhoea in cases of, iii. 752. causes of thefcetid odour of animals reduced by starva- tion, iii. 752. commencement of decomposition of the body before death from, iii. 152, 153. Statistics, note on the term, iv. 803, note. STATISTICS, MEDICAL, iv. 801. general remarks, iv. 801. 804. 1. of facts considered as the elements of statistical inquiries, iv. 804. phenomena of varying intensity, iv. 804. events brought about by a multitude of causes, iv. 804. 2. of the average and extreme results deduced from ob- servation, iv. 806. of extreme values derived from observation, iv. 813. Statistics, vital. See VITAL STATISTICS. Stntob/asts, winter egg, or hybernating ovum, of animals, s. [117]. [119], [127]. [128]. Stearine, i. 59. Steatoma, i. 63 ; iv. 97. Steatomatous deposits, i. 231, 232. concretions of pancreas, s. 110. Steenstrup, alternating generations of, s, 13. 34. the " nurse " of Steenstrup, s. 31. 37. parthenogenesis, s. 37. Stellate ligament, iv. 1032. Stellated vessels, iii. 16H. Steno, duct of, or duct of the parotid gland, iv. 423. 1404. Sten'inift, a genus of Myriapoda,'iii. 546. ct seq. Stenops, a genus of Quadrumana, iv. 214, et icq. See QUA- DHUMANA. characters of the genus, k. 214. Stentor Roeselii, iv. 7. Stcphanoceros, a g-nus of Rotifera, iv. 403. Eichornii, iv, 403. Stephanops, a genus of Rotifera, iv. 406. Steppes of High Asia, characters of the races inhabiting the , iv. 1351. Sterelmintha, a class of parasitic animals, ii. 111. digestive organs ot th;1, s. 296. acrite condition of the nervous and muscular systems in, iii. 534. generative organs of, ii. 410. Stereoscope, the, iv. 1450. Sternal labia of Arachnida, i. 203. nerves, iv. 753. Sternapsis thalassemoides, ova of, s. [126], Sterwo-cleido-mastoid muscle, i. 483. 734 ; iii. 565 ; iv. 817. action and relations, iii. 565, 583. Sferwo-costalis muscle, iv. 1055. action, iv. 1055. Sterno-hyoid muscles, i. 483; ii. 851 ; iii. 102. 105. 562 ; iv. 1022 ; s. 259. Slerno-hyoid branch of ninth pair of nerves, iii. 722. Sterao-mastoid muscle, i. 749 ; ii. 851 . artery for, i. 488. Sfemo-thyroid muscle, i. 483. Sterno-thyroid muscle, ii. 851 ; iii. 105. 563; iv. 1022 ; s. 259. Sternum, iv.1022. position and size, iv. 1022. surface, anterior or cutaneous, iv. 1022. posterior (mediastinal or cardiac), iv. 1022. borders of the sternum, iv. 1023. extremity, clavicular, iv. 1023. inferior, iv. 1023. connexions, iv. 1023. structure, iv. 1023. ligaments of the, iv. 1023. development or ossification of the sternum, iv. 1023. ossification of the first piece, iv. 1023. of the body, or second, third, and fourth pieces, iv. 1024. union of the points of ossification of the body of the sternum, iv. 1024. ossification of the xiphoid appendix, iv. 1024. condition of the sternum in emphysema of the lungs, iv. 1038. movements of the, in respiration, iv. 334. Stichidia of red Alga?, s. 221. Sticta pulmonacea, organs of reproduction of, s. 230. Stigmata, or respiratory organs of the Arachnida, i. 204. peritrema of, i. 204, 205. Slillingia, or tallow-tree of China, i. 58. Stimulants, considered as food, s. 395. action of, on the heart and circulating system, i. 721. Stimuli of muscular contraction, i. 717 ; iii. 521. remote, iii. 521. immediate, iii. 521. of nerves, iii. 720 K. mental stimuli, iii. 720 K. physical stimuli, iii. 720 K. effects of the Galvanic stimulus, iii. 720 X. Sting of the bee, ii.992. Stirrup-bone, or stapes, ii. 547, 548. Stapedius muscle, ii. 549. functions of the muscle, iii. 574. development, ii. 560. abnormal conditions, ii. 561. functions of the, ii, 573. STOMACH AND INTESTINE, s. 203. definition, s, 294. Comparative Anatomy, s. 295. Infusoria, s. 295. Gregarina and Opalina, s. 295. Polygastria, s. 295. Rotifera, s, 295. Entozoa, s. 295. et. Echinococci, s. 295. jS. Cestoid and Trematoid divisions, s. 295. •y. in many creatures closely allied to the pre- ceding, s. 296. Polypi fera, s. 296. in Hydra-, s. 296. in the Actiniae, s. 296. in the compound polyp, s. 296. in the tubularian polyp, s. 296. in the cilio-branchiate polyp, s. 297. Acalepha?, s. 297. Echinodermata, s. 297. Holothuriaj, s. 297. Annelida, s. 297. Epizoa, s. 298. Crustacea, s. 298. Insecta, s. 298. stomach in the larva, s. 298. in the perfect insect, s. 298. the ingluvies or crop, s. 298. the gizzard, s. 298. the stomach, s. 298. Arachnida, s. 293. Acari, or mites, s. 299. Aranei, or spiders proper, s. 209. Scorpions, s. 209. GENERAL INDEX. 865 STOMACH AND INTESTINE, comp. anat. — continued. Mollusca, s. 2i>9. Tunicata, s. 299. Brachiopoda, a. 299. Lamellibranchiata, s. 209. Gasteropoda, s. 299. Pteropoda, s. 299. Cephalopoda, a. 299. Fishes, s. 300. oesophagus, s. 300. stomach, s. 300. intestine, s. 300. appendices pylorica?, a. 300. Reptiles, s. 300. oesophagus, s. 300. stomach, s. 300. intestine, s. 300. in the Batrachian reptiles, 8. 301. Ophidian reptiles, s. 301. Chelouian reptiles, s. 301. Aves, s. 301. stomach, s. 301. oesophagus, s. 301. ingluvies or crop, s. 301 . proventriculus, or proper stomach, s. 301. gizzard, s. 301. intestine, s. 301. Mammalia, s. 301. Carnivora, s. 302. Insectivora, s. 30'2. Cheiroptera, s. 302. Pteropus, s. 3U2. Edentata, s. 302. Ruminantia, s. 302. Pachydermata, s. 303. Solipeda, s. 303. Rodentia, s. 303. Marsupialia, s. 303. Monotremata. s. 304. Cetacea, s. 304. Quadrumana, s. 304. general remarks, s. 304. absence of all digestive cavity, a. 304. simplest form of the digestive organ, as in the hvdriform polyp, s. 305. complex digestive organ, s. 305. Human Anatomy, s. 307. cardia, ii. 10. pylorus, ii. 10. in infancy, i. 68. stomach," s. 308. form, s. 308. dimensions, s, 308. attachment, s. 38. situation, s. 309. serous coat, iii. 943 ; s. 309. See also PERITONEUM ; and SEROCS MEMBRANE. muscular coat of, s. 310. longitudinal layer, s. 311. transverse or circular fibres, s. 311. oblique layer, s. 311. movements of the stomach, s. 31 1. in the fasting state, s. 312. at the commencement of digestion, s. 312. a. when a large quantity of food is hastily swallowed without masti- cation, s. 312. b. when a small quantity of liquid food is taken, s. 312. c. when in the ordinary state of mode- rate distension, with food pro- perly prepared by mastication, s. in the later stage of digestion, ii. 9 ; 8. 314. action of the pylorus, s. 315. simple eructation, or belching, s. 316. regurgitation, s. 316. vomiting, s. 316. rumination, s. 319. mucous membrane, s. 320 ruga?, s. 320. stomach tubes, s. 320. 337. limitary or basement membrane which forms these tubes, s. 321 . contents of these tubes, s. 321. tubes of the cardiac extremity in the dog, s. 322. tubes at the pyloric extremity of the organ, s. 32v!. lenticular glands, s. 324. matrix, a. 324. arteries of the stomach, s. 325. arteria coronaria ventriculi, or proper gas- tric artery, s. 325. the cesophageal and gastric branches, 8. 326. arteria hepatica, 8. 326. gastro duodenal is branch, s. 326. ga*tro-epiploica dextra, s. 320. pancreatico-duodenalis branch, s. 326. arteria pylorica, s. 326. STOMACH AND INTESTINE, human anat. — continued. arteria splenica, s. 326. gastro-epiploica siuistra, 8. 327. vasa brevia, s. 327. veins of the stomach, s. 327. vena pylorica superior, a. 327. vena gastro-epiploica dextra, s. 327. sinistra, s. 327. capillaries, s. 327. changes in the stomach during digestion, s. 328. gastric juice, s. 328. its physical properties, a. 329. specific gravity, a. 32». quantity, a. 330. its chemical composition, s. 330. the gastric acid, a. 330. salts of the gastric juice, a. 332. its organic substance or pepsine, s. 332. action of the gastric juice, s. 333, 334. peptone, a. 336. process of secretion, s. 337. small intestine, s. 339. duodenum, s. 340. superior transverse or hepatic portion, s. descending or vertical portion, s. 341. inferior transverse portion, s. 341. jejunum and ileum, s. 341. muscular coat, s. 342. movements of the intestine, s. 342. peristalsis, s. 342. antiperistalsis, a. 345. mucous membrane of the small intestine, 8. 345. valvulae conniventes, a. 346. intestinal tubes, or follicles of Lieberkuehn, s. 316. villi, s. 350. epithelium of the villi, s. 351. the basement membrane, a. 351. blood-vessels of the villi, s. 351. lacteals of the villi, s. 352. muscular constituents of the villus, ». 353. charges in the villi during digestion, s.355. intestinal follicles, s. 356. agminate follicles, s. 356. capsule of the follicle, a. 358. vessels of the follicle, s. 358. contents of the follicle, s. 359. function of the agminate follicles, s. 359. solitary follicles, a. 360. racemose, or Brunn's glands, s. 361. large intestine, s. 362. size and shape, s. 362 caecum (formerly the blind gut), s. 362. situation of the caecum, s. 363. its shape, s. 363. serous covering, s. 363. mucous membrane of the caecum, s. 363. apertures of the caecum, s. 363. the ileo-caecal valve, s. 363. vermiform appendix, s. 365. colon (formerly the great gut), a. 365. the ascending colon, a. 365. the transverse colon, s. 365. the descending colon, s. 365. the sigmoid flexure, s. 365. appendices epiploicae, a. 366. * movement of the large intestine, a. 366. mucous membrane of the colon, a. 368. rectum, s. 368. the three portions : the first, or oblique segment, s. 368. middle, or arcuate segment, s. 369. third, or terminal portion, s. 369. structure of the rectum, s. 369. muscles of the anus, s. 369. sphincter ani interims, a. 369. sphincter ani externus, a. 369. levator ani, s. 369. movements of the rectum, s. 370. defaecation, a. 370. raucous membrane of the rectum, a. 371. faeces, s. 372. physical properties of the faeces, s. 3/3. odour and colour, s. 373. quantity evacuated, a. 374. specific gravity of the faeces, 8. 374. mechanical composition of the faeces, 8.374. chemical composition, 8. 375. intestinal gases, s. 376. 1. air may be introduced into the intestinal canal from without the body, s. 376. 2. gases may be developed in the alimen- tary canal from the decomposition of the food which it contains, a. 377. 86G GENERAL INDEX. STOMACH AND INTESTINE, human anat. — continued. 3. it has been supposed that gases arc set free in the intestinal canal by a kind of secretion or transpiration from the blood, s. 377. 4. probable source of intestinal gases pre- sent in diseased subjects, s. o78. arteries of the intestines, s. 379. superior mesenteric artery, s. 379. inferior mesenteric artery, s. 380. veins of the intestines, s. 380. superior mesenteric vein, s. 381. inferior mesenteric vein, s. 381. food. s. 382. nature of the food, s. 382. milk, s. 384. constituents of food, s. 384. 1. protein compounds, s. 384. 2. hydro-carbons, s. 386. 3. hydrates of carbon, s. 386. 4. water, s. 387. 5. salts, s. 388. varieties of food, s. 388. animal food, s. 389. fat, s. 390. blood, s. 391. brains, s. 391. glands, s. 391. bone, s. 391. eggs, s. 391. varieties of milk, s. 391. butter, s. 392. cheese, s. 392. vegetable food, s. 389. 393. corn, s. 393. proteinous constituent, s. 393. amylaceous constituent, s. 393. hydrocarbons, s. 393. salts, s. 3U3. leguminous seeds, s. 394. potato, s. 394. succulent vegetables, s. 395. seasonings, s. 395. chloride of sodium, or common salt, s. 395. acids and acrid substances, s. 395. stimulants, s. 395. tea and coffee, s. 396. alcohol, s. 396. dietaries, s. 396. relations of digestion to nutrition generally, s. 397. prehension, s. 397. mastication and insalivatiou, s. 397. deglutition, s. 398. gastric digestion, s. 398. intestinal digestion, s. 398. the bile, s. 399. development of the alimentary canal, s. 401. Abnormal Anatomy of the stomach and intestine, s. 403. malformations, s. 403. 1. those which appear to depend on an arrested or deficient development, s. 403. 2. attended by an excess of size, s. 403. 3. only referable to enors of development, the causes of which are unknown : or to mal- formations of adjacent parts, s. 404. morbid conditions— size, s. 404. constriction, s. 404. dilatation, s. 405. thickness, s. 405. changes in the situation, s. 405. torsion of the intestine, s. 406. intus-susception, s. 406. abnormal conditions of its texture— softening, s. 407. hyperaemia, s. 408. haemorrhage, s. 409. inflammation, s. 410. catarrhal inflammation, s. 410, puriform inflammation, s. 411. croupy or diphtheric inflamma- tion, s. 411. acute gastritis, s. 414. dysenteric inflammations, s. 415. ulceration, s. 416. ulcer of the stomach, s. 416. lientery, s. 418. hypertrophy s. 418. polypi, s. 419. calculi, iv.83. tubercle, s 419. cancer of the intestinal canal, s. 420. of the stomach, s. 421. stricture of the intestine, s. 422. nerves of stomach and intestine, s. 464. See SYM- PATHETIC NERVE. effects of the lesion of the vagi upon the secretion of mucus upon the inner surface of the sto- mach and intestines, iii. 900. and upon rapidity of absorption from the inner surface of the stomach, iii. 901. Stomach of the horse, iv. 732. of Fishes, iii. 981. ol Kodentia, iv. 38G. of Keptilia. iv. 296. of Kuminantia, ii. 11 ; s. 535. See RUMINANTIA. of Carniyora, i. 478. See CARNIVOKA. Stone, operations for the. See Lithotomy. S-rofyvi, or maternal affection, general final cause of, iii. 15. Stusatea, a genus of Myriapoda, iii. 546, et sea. Straight nnus, iii. 631. Straits of the pelvis, s. 127. Strangulated hernia. See HERNIA. Strangulation, de;ith by, appearance of the body after, i. 259. Strength of the human body at different ages, i. 74. Strepsiptera, an order of Insecta, ii. 866. characters and habits of the order, ii. 866. anomalous structure of, ii. 866. Stricture of the intestine, s. 422. of the oesophagus, iii. 761. of the urethra, iii. 925 ; iv. 1260. spasmodic, iv. 1260. permanent iv. 1260. varieties of permanent stricture, iv. 1260. causes of stricture, iv. 1262. in females, iv. 1266. Slrigamia, a genus of Myriapoda, iii. 547. Stromal and non-stromal formations. See PRODUCTS, ADVENTITIOUS. Strongylut armatus, a species of parasitic worm, ii. 127. ova of, s. [123]. dentatus, ii. 1*7. gigas, a parasite of the urinary organs, ii. 124, 125. 129, 130. nervous system of the, iii. 607. horridus, a parasite found in the water-hen, ii. 127. Struma, characters of the urine in, iv. 1*93. Strychnine, effects of, on paralytic limbs, iii. 38. 40. its peculiar influence upon'the spinal cord, iii. 721 G. effects of ether on animals poisoned by strychnine, iii. 721 H. Sturgeon, skeleton of, iii. 965. Sturionidts, a family of Fishes, iii. 956, et scq. characters of the family, iii. 956. Stye, or hordeolum, iii. 83. Styli of animalcules, iv. 6. Stylo-glpssus muscle, i. 734 ; iii. 565. action and relations, iii. 565. Stylo-hyoid ligament, i. 734. muscle, i. 734 ; iii. 105. 564. action and relations, iii. 564. nerve, iii. 901 ; iv. 547. Stylo-masluid artery, ii. 542. 556. foramen, i. 734. Stylo maxillary ligament, i. 734 j ii. 214 ; iv. 938. Stylo-pharyngeus muscle, i. 734 ; iii. 947. relations and use, iii. 947. Styloid process, i. 734 ; iv. 1506. of ulna, ii. 163, 164. of temporal bone, i. 727, 728. Slylopidfc, a family of Insects of the order Strepsiptera, ii. 8L;6. Stylops Spencii, ii. 866. Sub-arachnoid fluid iii 641. space, posterior, iii. 638. effusions into the, iii. 716. SUBCLAVIAN ARTERIES, i. 189. 230; iii. 110. 577,578; iv. 814. subclavian vein, iv. 815. first stage of the right subclavian artery, iv. 815. anterior relations, iv. 815. a. right vena innominata, iv. 815. b. internal jugular vein, iv. 815. c. vagus nerve, iv. 815. d. cardiac filaments of the sympathetic nerve iv.815. e. phrenic nerve, iv. 815. /. vertebral vein, iv. 815. first stage of the left subclavian artery, iv. 816. relations, iv. 816. differences between the right a"d the left sub- clavian arteries in their first stage, iv. 816. length, iv. 816. position, iv. 816. direction, iv. 816. relations, iv. 816. a. pleura, iv. 816. b. veins, iv. 816. 1. satellite vein of the right gubcla- vian, iv. 810. 2. internal jugular vein, iv. 816. 3. vertebral vein, iv. 816. c. nerves, iv. 816. d. thoracic duct and oesophagus, iv. 816. subclavian arteries in their second stage, iv. 817. anterior relations, iv. 817. subclavian artery in its third stage, iv. 817. anterior relations, iv. 818. anomalies in the origin of subclavian arteries, iv. 8!8. 1. the right sub- lavian, iv. 818. a. may occupy the usual position of the inno- minate artery, iv. 818. GENERAL INDEX. 867 SUBCLAVIAN ARTERIES — continued.' b. may be the second in numerical order of the branches of the arch, ir. 818. c. may be the third of the branches of the arch, iv. 818. d. may be the last branch of the aorta, iv. 818. e. sometimes arises below the arch, iv. 818. 2. the left subclavian artery, iv. 819. a. sometimes more approximated than usual to the origin of the left carotid, iv 819. b. its origin sometimes fused into that of the left carotid, iv. 819. branches of the subclavian arteries, iv. 819. vertebral artery, iv. 819. origin, iv. «19. relations, iv. 820. branches, iv. 8'Jl. basilar artery, iv. 820. origin and relations, iv. 820, 821. blanches, iv. 821. varieties occasionally observable in the vertebral arteries, iv. 822. 1. of origin, iv. 822. 2. of size, iv. 822. 3. of course and relations, iv. 822. vertebral vein, iv. 82*. mammary artery, internal, iv. 822. origin and course, iv. 822. branches, iv. 822. varieties, iv. 823. thyroid axis, iv. 823. branches, iv. 823. 1. interior thyroid artery, iv. 823. origin and course, iv. 823. anterior relations, iv. 823. branches of inferior thyroid, iv. 824. a. aneria cervicalis ascendens, iv. 824. b. descending branches, iv. 82-1. c. terminal or thyroid branches, P24. 2. supra-scapular artery, iv. 824. 3. arteria-transversalis colli, iv. 824. cervicalis superricialis, iv. 824. arteria cervicaiis profunda, iv. 824. intercostal artery, superior, iv. 824. origin and course of these arteries, ir. 824 operative proceedings, iv. 825. lirst stage, iv. 825. second stage, iv. 826. third stage, iv. 8^7. Sub-clavian vein, iii. 578; iv. 815. 817. 1407. origin and course, iv. 1407. collateral branches, iv. 1408. Subclavius muscle, i. 360 ; iv. 755. Subcunjunctival ecchymosis, iii. 85. Subcutaneous cellular tissue, i. 3*. 216. 3G7. of the cranium, i. 747. 74'J. 5^8. elbow, ii. 63. hand, ii. 524. 528. Subcutaneous or superficial bursae, i. 467. veins, iv. 13^7. Sublingual artery, i. 486 ; iv. 1141. fossa, ii. 214. gland, ii. 214; iv. 424. position, form, and dimensions, iv. 425. ducts of the sublingual, iv. 425. arteries, veins, nerves, and lymphatics, iv. 425. Sub-lobular veins, iii. 173; iv. 1414. Submaxillary fossa, ii. 214. gland, iv. 424. position, form, and dimensions, iv. 424. excretory canal, or Wharton's duct. iv. 424. arteries, veins, nerves, and lymphatics, iv. 421. Submental artery, i. 486. vein, iv. 1404. Suboccipital fossa, i. 367. nerve, iii. 658. 707. posterior branch, iv. 750. Sub-peritoneal cellular tissue, i. 13. Hub-pubic, or obturator, groove, s. 116. ligament, or ligamentum arcuatum, s. 12G. ossification of the, s. 207. 705. Sub-rutund lovea, ii. 530. Sub-scapular artery, iv. 436. fossa, ii. 157. muscle, i. 362; iv. 755. nerves, iv. 755. inferior, i. 361. superior, i. 361. veins, iv. 1407. vessels, i. 359. Subslantia perforate antica, iii. 731. media, iii. 673. Subsultus tendinum, i. 61. Succulent vegetables, considered as food, s. 395. chemical composition of, s. 3'J5. Succus lachryrnalis, iii. H8. Sugar, properties of, as food, ii. 14 ; g. 386. natural and artificial conversion of gum, starch, and lignin into, iii. 153. Sugar — continued. method of determining the presence of, in organic substances, iii. 7U6. quantitative analysis of, iii. 709. of milk, iii. 360. qualities of, iii. 300. chemical analysis of, iii. 3GO. Sugar disease, iv. 99. See Diabetes, saccharine. theories of the pathology of, iv. 9ra-acromial twigs of nerves, iv. 571. S«/>;a-clavicular nerve, iii. 572 ; iv. 753. 755. 818. Stt/M'fl-maxillary nerve, iv. 548. Sw/jra-orbicular nerves, iv. 547. Su/wa-orbital artery, i. 491. 748 j iii. 93. 786. nerve, i. 748; iii. 784. vein, iv. 1404. Sz/jH-a-orbitar cerebral convolution, iii. 696. Supra-oibnzry foramen, i. 729. Supra-renal artery, inferior, iv. 833. media, iv. 833. superior, iv. 833. SUPRA-RENAL CAPSULES, iv. 827. definition, iv. 827- I. the larger series constituted by the differences of form of supra-renal capsules in the animal king- dom, iv. 827- in Man, iv. 827. accessory renal capsules, iv. 828. 832. in Mammalia, Birds, Reptiles, and other Veitebrata, iv. 828—830. II. minute structure, iv. 830. cortical substance, iv. 831. constituents, iv. 831, 1. fine molecules, iv. 831. 2. fatty granules, iv. 831. 3. nuclei, iv. 831. 4. cells in different stages of their develop- ment, iv. 831. medullary substance, iv. 832. blood-ves'sels in the supra-renal capsules, iv. 833. arteries, iv. 833. veins, iv. 833. lymphatics, iii. 227 ; iv. 833. nerves, iv. 833. structure of supra-renal glands, renal capsu'e*. glandules succenturiatae, of birds, i. 348 ; iv. 834. See AVES. in Reptiles, iv. 834. in Fishes, iv. 834. III. development, iv. 836. IV. physiology, iv. 837. functions, iv. 445. 868 GENERAL INDEX. Supra-renal vein, iv. 833. 1413. Stt/>ra-»capltlar artery, iv. 435. 824. branches, iv. 435. origin and relations, iv. 824. nerve, iv. 434. 755. S?4~. nerves affected by the phenomena of sensation and motion, iv. 854. continuous and contiguous sympathy, iv. 855. Syatphysi$, \. 257. pubis, i. 4*; s. 115. 125. sacro-iliac, i. 249. Sympodia, or siren-like form of monstrosity, iv. 964. Synarthrosis, i. 254. varieties of, amphiarthrosis, i. 255. gomphosis, i. '255. schindylesis, i. 255. suture, i. 255. diarthrodicajform of articulation, i. 255. Synchtsta, a genus of Rotifera, iv. 404. Sync/iondrosis, i. 2J9. 257. Sync/tysis, spaikling, causes of the sparkling appearance, Synciput, i. 725. Syncope, phenomena of, iii 159. cause of, i. 416. produced by the operation of phlebotomy, i. 228. Syncorne, mode of reproduction of the, s. 18. Syngnathidas, a family of Fishes, iii. 957. Si/ngnat/ius, iii. 986. Synneurosis, i. 2o7. Synoicum, a genus of Tunicata, iv. 490, et seq. characters of the genus, iv. 1190. SYNOVIA, iv. 856. definition, iv. 856. chemical examination of synovia, iv. 856. Synovial bursce of temporo-maxillary articulation, iv. 937. capsule, acute inflammation of a, effects of, on the action of the heart, i. 797. of eibow, ii. 66. of knee, iii. 46. cavities, calcareous, deposits in the, iv. 90. membranes in particular. See Articulations in par- ticular. of the ankle-joint, i. 153. acute inflammation of the, i. 162. of hip-joint, ii. 779. of radio-ulnar articulations, iv. 229. of shoulder-joint, iv. 575. of tibio-fibular articulations, iv. 1118, 1119. of wrist-joint, iv. 1507. membranes in general. See SEROUS and SYNOVIAL MEMBRANES. sheaths of tendons, constitution of, iv. 518. Synovial membrane, diseases of the, of the elbow-joint, ii. Synnvitis coxae, case of, ii. 788. Synovitis of the elbow-joint, ii. 77. Syphilis, caries from, i. 450. a cause of inflammatory state of the brain, iii. 713. treatment, iii. 713. effects of syphilis on the anus, i. 183. foetus in utero affected by it, ii. 333. prodticed by contact with morbid saliva, iv. 420. syphilitic ofchitis, iv. 1008. syphilitic ulceration of the tongue, iv. 1156. small circular superficial ulcers, iv. 1156. rhagades or fissures, iv. 1156. glossy tubercle, iv. 1156. phagedaenic ulcers, iv. 1157. ulcerations of the larynx caused by, iii. 119. treatment of syphilis by mercury, iv. 802, 803.* Syringograde motion, explanation of, iv. 1241, note. Ki/ringogrades, mode of locomotion of the, iii. 433. Syro- Arabian, or Semitic, group of languages, iv. 1347. characters of the Syro-Arabian nations, iv. 1347. Syssarcosi*, i. 257. Systemic heart, ii. 579. See HEART (normal anatomy). Systole, or contraction, of the heart's auricles and ven- tricles, ii. 602,603. See HEART, PHYSIOLOGY op. meaning of the expression " systole of the heait," ii. 603. T. T fractures of the femur, iii. 68. Tabanidte, or bloodsuckers, ii. 867. Tabula vitrea, i. 742. Tadpole, i. 93. See AMPHIBIA. digestion, organs of, i. 96. metamorphosis, i. 106. of the os hyoides in the tadpole, iii. 835. respiratory organs of the, s. 278. 280. respiration, organs of, i. 98. skeleton of, structure of, i. 96. vertebrae of, i. 93. Tcenia filiformis, ova of, ii. 142. polvmorpha, ii. 142. semicircularis, iii. 675. 699. 702. solium, description of the, ii. 120, 121. digestive organs of the, s. 295. mode of reproduction of, s. 29. sphaenocephalus, a species of tape-worm, it 13 . Teenies, or tape-worms, ii. 116. 120. digestive apparatus in, ii. 131. forms and malformations of, ii. 121. muscular system of, ii. 128. organisation of, ii. 120, 121. generation, organs of, ii. 137. mode of reproduction of, s. 27. sexual joint or proglottis of the tape-; [124]. nervous and muscular tissues not discernible in the, iii. 534. 607. Taenice armatae, ii. 121. 127. inermes, ii. 121. rostellatae, ii. 121. Teenioides, a family of Fishes, iii. 957. Tahitians, physical characters of the, iv. 1362. portrait of a Tahitian female, iv. 1362. cranium of a native of, iv. 1326. pelves of, s. 150. Tail of birds, use of the, in flight, iii. 429. of fish, considered as an organ of locomotion, iii. 437. of monkeys, use of the, iii. 456. Tallow, vegetable, i. 58. Tallow-tree (Croton sebiferum) of China, i. 58. Talpa, or mole, ii. 994, et seq. pel vis of the, s. 164. Talpidee, or mole family, ii. 994. characters of, ii. 994, et seq. See INSECTIVORA. Tamulian language of Southern India, iv. 1349. affinities between the, and the language of the Austra- lian aborigines, iv. 1363. Tanning, art of, ii. 404. Tapelum, inner villous surface of choroid coat, ii. 179. Tape-worms. See Teenies. Tapir Americanus, anatomy of the, iii. 863. et seq. See PACHYDERMATA. organs of voice of the, iv. 1493. pelvis of the, s. 156. Tardigrade, or sloth, digestive organs of the, s. 302. pelvis of, s. 161. origin of the name "tardigrade," s. 162. Tarsal, or palpebral, arches, iii. 93. cartilages, iii. 78. 81. ligaments, iii. 81. Tarsius, a genus of Quadrumana, iv. 214, et seq. See QUADROMANA. Tarso-metatarsal articulations, ii. 344. Tarsus, bones of the, ii. 339. articulation of two rows of, to each other, ii. 343. anterior row of, ii. 339. joints of, ii. 342. posterior row of, ii. 339. structure and development, ii. 341. motion of the tarsal joints, ii. 344. abnormal conditions, ii. 347. Tartar, odontoliths, or salivary calculi, of teeth, iv. 83. 419. Tartini, anecdote of, iv. 687. Tasmania, head and face of a woman of, iv. 1316. TASTE, iv. 856. definition, iv. 856. seat of the sense of taste, iv. 857. conditions of the sense of taste, iv. 857. nerves of taste, iv. 858. speciality of the nervous fibres which convey the gustative impressions, iv. 859. influence of the facial nerve on the sense of taste, iv. 553. and of the glosso-pharyngeal nerve, ii. 498. See FACIAL NEHVB ; GLOSSO-PHAKYNOEAL NERVE. gustative papillae, iv. 860. exercise of the sense of taste, iv. 861. power of distinguishing sapors with remarkable acuteness, iv. 861, 862. suspension of this power, iv. 862. influence of habit in blunting the sensibility to particular tastes, iv. 862. sense of taste affected by illness, iv. 862. purpose of the sense, iv. 863. the sense of taste in infancy, i. 73. and in old age, i. 80. 870 GENERAL INDEX. Taste, organs of, in various animals. See under their headings. Tam-in, or gallenasparagin, in ox-gall, i. 375. Tea, as an article of diet, ii. 14 ; s. 306. chemical constituents of, s. 390. effects of, on the system, s. 396. Tears, iii. 94. tissues of which true teeth consist, iv. 8G4. dentine, iv. 864, 865. cement (casmentum, crusta petrosa), iv. 8G4, 865. enamel (encnustum, adamas), iv. 865. characteristic examples of the above-defined tis- sues, and their different combinations in dif- ferent teeth, iv. 865. dental system of Fishes, iv. 873. number, iv. 873. form, iv. 873. situation, iv. 873. substance of the teeth, iv. 877.' development of the teeth of Fishes, iv. 880. dental system of Reptiles, iv. 882. number, iv. 883. situation, iv. 883. form, iv. 883. attachment, iv. 883. substance, iv. 884. structure, iv. 884. development, iv. X8">. batrachian modifications, iv. 885. poisonous serpents, iv. 887. poison-fangs and glands, iv. 887, 88S. Saurians, iv. 889. scincoid lizards, iv. 891. iguanas, iv.^892. Varanians, iv. 894. Thecodonts, iv. 894. Knaliosaurs, iv. 895. Crocodilia, iv. 895. development, iv. 896. dental system of Mammalia, iv. 898. deciduous and permanent teeth of a child six years of age, iv. 817. of other Mammalia, iv. 818, el seq. tusks of the elephant, &c., iv. 9'24, ct seq. Teeth of Carnivora, i. 478. See CARNIVORA. of chimpanzee, iv. 917. elephant, iv. 924. Insectivora, iii. 1000. See INSECTIVORA. kangaroo, iv. 933, 934. Pachydermata, 865. Rodentia, iv. 382. Ruminantia, s. 532. the horse, iv. 732. Amphibia, i. 95. Reptilia, iv. 287. Rotifera, iv. 412. Tcgenaria domcstica (house spider). See ARACHNIDA; Araneidce. Tenumentary membranes. See Mucous MEMBRANE. TEGUMENTARY ORGANS, s. 47.1 § 1. what constitutes a tegumentnry organ as distin- guished from «ny other, s. 474. § 2. morphology of the integuments, s. 476. nails, s. 477. claws, s. 477. (hoofs, s. 477. horns, s. 478. 516. glands, s.478. hairs, ii. 227 ; s. 478. the porcupine's "quill," s. 478. feathers, s. 479. scales of fishes, s. 480. § 3. histology of the tegumentary organs, s. 484. 1. hydroid and actinoid polypes, s. 4*4. 2. integument of the Annulosa, including the Worms and Echmoderms, s. 485. TEGUMEXTARY ORGANS, histology — continued. 3. integument of the Mollusca, including the Ascidians and Polyzoa, s. 4s8. excretionary integument of the Mollusca, s. 488. the membranous shell substance of Dr. Car- penter, s. 489. conversionary integument of the Mollusca containing cellulose, s. 493. 4. integument of the Vertebrata, s. 495. conversionary horny organs, s. 495. structure of hairs, spines, and feathers, s. 496. composition of the shaft of a hair, s. 496. cuticle, s. 496. cortical tissue, s. 496. medullary substance, s. 497. hair sac, "s. 497. outer root-sheath, s. 497. fenestrated inner root-sheath, s. 497. im perforate root-sheath, s. 497. spines and feathers, s. 498. the shaft, s. 498. the quill, s. 499. tegumentary glands, s. 499. sudoriparous glands, s. 500. scales of fishes, s. 501. structure of the enderon, s. 5^2. pigment of the enderon, s 502. papilla? of the enderon, s. 503. sensory appendages of the enderon, s. 503. the corpuscula tactus, s. 5( 3. Panician bodies [see also the article PANICIAN BODIES], s. 504. muscles of the enderon, s. 505. calcareous deposits in the enderon, s. 506. muscles used in the tegumentary system, iii. 543. Tegumentary organs of Edentata, ii. 54. See EDENTATA. of Insectivora, ii. 1004. See INSECTIVOKA. Reptilia, iv. 324. Amphibia, i. 102. Birds, i. 319. See AVFS. Fishes, iii. 968. Insects, ii. 993. See INSECTS. of the Arachnida, i. 201. Crustacea, i. 752. Gasteropoda, ii. 379. See GASTEROPODA. F.chinodermata, ii. 31. Entozoa, ii. 125. Tunicata, iv. 1193. Rotifera, iv. 409. Tegumentary system of tongue, iv. 1135. cutis, iv. 1135. basement membrane, iv. 1135. epithelium, iv. 1135. papillary structure of the tongue, iv. 113G. different papilla?, iv. 1136-1139. structure, iv. 1139. functions, iv. 1140. Tcla elastica, ii 265. See FIBROUS TISSUE. TEMPERAMENT, iv. 935. definition, iv. 935. Galen's doctrine of the four humours of the blood,— bilis, sanguis, atrabilis, et phlegma, Jv. 935. sanguine temperament, iv. 936. melancholic, iv. 936. phlegmatic and choleric, iv. 938. nervous temperament, iv. 936. Temperature of the air, effect of, in producing hibernation, ii.765. influence of climate on animal luminousness,iii,199. effects of temperature on the quantity of carbonic acid gas in the expired air, iv. 348. animal. See HEAT, ANIMAL. sense of. See TOUCH. Temples, i. 725. Temporal aponeurosis, i. 729. Temporal artery, i. 488 ; ii. 227. 556. anterior, i. 488 ; iii. 93. deep, i. 748. anterior deep, i.489. posterior deep, i. 489. middle, i. 488. posterior, i. 488. superficial, i. 748. bone, i. 733. connexions, i. 735. development, i. 735 mastoid portion, i. 734. petrous portion, i. 733. squamous portion, i. 734. fascia, i. 749. fossa, i. 727. 729. 734. 738. line, i. 729. 735. muscle, i. 729. 734. 749. nerve, deep, i. 749 ; iii. 787 ; iv. 547 branch of lachrymal nerve, ii. 283. external, ii. 284. superficial, ii. 293 ; iii 903. auricular branch, iii. 903. deep, ii. 291. superior, ii. 555. GENERAL INDEX. 871 Temporal— continued. or posterior superior, border of malar bone, ii. 21 1. regions, origin of the term " temporal," i. 749. sulcus, i. 727. vein, iii. 903; iv. 1405. superficial temporal, iv. 1405. middle temporal, iv. 1405. deep, iv. 1405. 7V»«/>oro-facial nerve, iii. 904. Temporo-ma.\;\r nerve, ii. 2*4 ; iii. 7^7. external temporal branch, malar branch, ii. 2*4. TEMPORO-.MAXILLAHY ARTICULATION, iv. 937. ill human anatomv, iv. 937. bones, iv/037. interarticular fibro-cartilage, iv. 937. synovial bursa?, iv. 937. ligaments, iv. 1)37. ies,iv. 93S. motions of the joint, iv. 938. abnormal anatomy of the temporo-maxillary joint, iv. accidents, iv. 938. dislocation of the condyle of the lower jaw, iv. 9-18. both condyles dislocated, iv. 938. one condyle only dis ocated, iv. 939. congenital malformation, iv. 9W. congenital luxation of the inferior maxilla, iv. 9o9. disease, iv. 939. chronic rheumatic arthritis, iv. 939. necrosis of the coijdyle of lower jaw of a scro- fulous boy, iv. 939. anchylosis, iv. 939. comparative anatomy, iv. 940. in Mammalia, iv". 940. Aves, iv. 941. Reptilia. iv. 941. Pisces, iv 941. homology of the joint, iv. 941. TVwi/Joro-ina'xillary vein, iv. 1405. communicating branch from, iv. 1406. 7V//'/Joro-parietal region, i. 749. TVwporti-zvgomatic, Or internal, surface of malar bone, ii. 211. Tendinous cords, ii. 581. 583. 601. rings, arterial, ii. 587. aunculo- ventricular, ii- 587, sheaths, essential properties and offices of, ii. 264. structure in the arterial valves of heart, ii. 589. in the auriculo-ventricular valves, ii. 589. texture of the heart, ii. 5-7. Teiido Adiillis, i. 150; iii. 139. rupture of, iii. 132. division ot the, in cases of club-foot, iii. 132. ocnli, or tendo palpebrarum, iii. 81. Tendons of muscles. See Muscles in particular. essential properties and offices of, ii. 265. See MUS- CLE. fatty accumulation within the sheaths and amid the fibres, iv. 96. Tenebrionidte, or meal-beetles, ii. 163. Tensor membranae tympani muscle, i. 734. palati muscle, i. 727 ; iii. 951 . relations and action, iii. 951. tarsi muscle, iii. 92. action, iii. 93. origin, iii. 92. relations, iii. 92. tympani muscle, i. 734 ; ii. 548. functions of the, ii. 574. use of the, ii. 573. vag'nae femoris muscle, ii. 264 ; s. 137. Tentacle s, brachial, labial, and ophthalmic, of Cephalopoda, i. 5'2i). See CEPHALOPODA. Tentacula of Pteropoda, iv. 174, 175. Tenthrcdo, or saw-fly, migration of, iii. 16. Tentorium cerebelli, i. 728. 732, 733; iii. 629. 673. 6S7. partial deficiency of the tentorium, iii. 713. TERATOLOGY, iv. C«42. definition, iv. f'42. 1. original mallormation of the germ. iv. 942. a ascribable to the mother, \\ b. to the father, iv. '.M2. II. deformity of the originally well-formed germ, iv. 042. 1. by mental impression of the pregnant mother, iv. 942. 2. external injury during pregnancy, iv. 1943. 3. attributable to diseases of the ovum and the fcetus. iv 943. 4. impeded development of the fcetus by some remote and unknown cause, iv. 944. Malformations of the Ovum. iv. 916. 1 . mola botryoides or hydatica, — hydrometra aqua- tica, iv. 946. 2. separation of the placenta into lobes or coty- ledons, iv. 946 3. vessels of the umbilical cord separated near the placenta, iv. 917. 4. the umbilical cord too long, iv. 947. TERATOLOGY, malformations of ovum — continued. 5. the umbilical cord too short, iv. 947. 6. absence of one of the umbilical arteries, iv. 947. 7. increased number of the vessels of the cord, iv. !)4*. 8. persistence of the umbilical vesicle, iv. 948. 9. constriction of the umbilical cord, iv. 948. 10. the umbilical cord too thick, iv. 948. Malformations of the Foetus, iv. 948- A. Monstrosities produced by an Arrest of deve- lopment, iv. 948. I. Non-closure of tne anterior part of the bod v, iv. 94S. 1. fissure of the whole anterior wall of the body, iv. 948. complete ectopia of the thoracic and abdominal viscera, iv. 949. 2. fissure of the thorax, iv. 949. ectopia cordis, iv. 949. 3. fissure of the anterior abdominal wall, iv. 950. a. complete ectopia of the abdominal viscera, iv. 950. 6. congenital umbilical hernia, iv. 950. c. congenital ventral hernia, iv. 950. rf. acquired umbilical hernia iv. 950. 4. fissure of the pubic and hypogastric re- gions, iv. 950. a. formation of a cloaca, iv 950. b. congenital fissure of the urinary bladder, iv. 951. c. ectopia vesicae urinaria?, iv. 952. d. inversio vesicae urinariae, iv. 952. 5. cervical fissure (fistula colli congenita), iv. 953. 6. fissure of the free, iv. 953. a. complete fissure of the face. iv. 953. 6. double labium leporinum, iv. 953. c. single hare lip, iv. 953. d. fissure of the palate without a hare lip, iv. 953. e . fissure of the under lip, iv. 954. II. Fissure of the skull, — aerania, iv. 954. first type: want of the brain and expo- sure of the whole basis of the skull, iv. 954. se-ond type : the denuded surface of the basis cranii occupied by a spongy sub- stance instead of brain, iv. 955. third type: the surface of the basis cranii only partially denuded, — a spongy tumour occupying the place of the brain, iv. 955. fourth type: the skull flat, more evolved, but having an opening through which the brain protrudes as a hernia, iv. 956. III. Fissure of the back part of the body, iv. 957. hydrorachis and spina bifida, iv 957. IV. Hydrocephalus congenitus, iv. 958. hydrocephalus internus and externus, iv. 958. V. Acephali, or fcetus without a head, iv. 958. first type: acephali in the form of a rounded mass, without any indication of extremities, iv. 5. 2. want of the intermediate parts in the extremities, so that the hand 'is at- tached immediately to the shoulder, and the foot to the hip, iv. 966. 3. limbs too short, iv. 966. 4. limbs which seem to be truncated, iv. 966. 5. diminished number of ringers and toes, iv. 966. 6. coalesced fingers and toes, iv. 966. 7. abnormal direction of the foot. See FOOT, ABNORMAL CONDITIONS OF THE. VIII. Cyclopia, iv. 967. IX. Deficiency of the under-jaw,— Monotia, iv. 967. 1. total defect of the opening of the mouth, iv. 967. 2. the opening of the mouth represented by a fissure at the inferior surface of the face, iv. 967. 3. too short an under-jaw, iv. 967. B. Montrosities produced by Exctss of develop- ment, iv. 967. I. Foetus in fcetu, iv. 9r>7. 1. a foetus more or less perfect contained in the cavity of the body of its twin brother or sister, iv. 967. a. in the uterus, iv. 967. b. in the abdomen, iv. 967. c. in the anterior mediastinum, iv. 968. d. in the scrotum and testes, iv. 968. e. in the stomach, iv. 968. /. in the intestinal canal, iv. 968. f. in the orbit, iv. 968. . at the tentorium of the dura mater, iv. 968. f. at the palate, iv.968. 2. the more or less developed rudiments of a foetus adhere, in the form of a tumour, to the external surface of a second body, and are covered by the external integuments, iv. 968. rt. to the cheek, iv. 968. 6. to the neck, iv. 968. c. to the epigastric and umbilical re- gion, iv. 968. d. to the sacral and perineal region, iv.968. II. Double monsters, in which one of the foetuses is more or less perfect, and the other merely an appendix to it, — heter- adelphi, iv. 968. first species : the appendix consisting of a head only, iv. 968. second species : the appendix consisting of more or less developed extremities only, iv. 968. third species : ^ttie appendix is an ace- phalus with four extremities, iv. 969. fourth species: the appendix a complete body with a head and four extremities, iv. 969. III. Double monsters, iv. 969. 1. anterior duplicity, iv. 969. 2. lateral duplicity/iv. 970. 3. inferior duplicity, iv. 972. 4. posterior duplicity, iv. 972. 5. superior duplicity, iv. 972. generalisations, iv. 972 — 976. hermaphrodism in double monsters, ii. 736. Terebella, instinct guiding the formation of its habitation. iii. y. Tcrehrantia, a section of Hymenoptera, ii. 86.1, 866. characters and habits of the section, ii. 805. Tercs ligament of the hip-joint, i. 13. 251. major muscle, i. 217. 360. 362 ; iv. 436. minor muscle, i. 217; iv. 436. Teretes lacerti, ii. 581. Termites, or white ants, ii. 865. See also Ants, white. Termitina, a section of Neuroptera, ii. 865. characters of the section, ii. 865. Terrestria, a section of Hemipttra, ii. 868. Test, or shell, of Tunicata, iv. 1193. Testacea, characters of the family, i. 521. Testes (of brain), iii. 677. 685. TESTICLE, ii. 422. 481 ; iv. 976. human anatomy, iv. 976. I. protective parts, or tunics, iv. 976. tunica vaginalis, iv. 976. appendage, iv. 977. tunica albuginea, or tunica propria, iv. 977- corpus Highmori, iv. 977. mucous membrane of the, iii. 487. 408 II. glandular or secreting structure, iv. 977. tubuli seminiferi, iv. 978. rete testis, iv. 977. 979. internal composition of the testis, iii. 498. III. the excretory parts, iv. 979. epididymis, iv. 979. globus major, or head, iv. 979. minor, or tail, iv. 979. vasa efferentia, iv. 979. coni vasculosi, iv. 979. vasculum aberrans, iv. 980. vas deferens, iv. 980. IV. vessels and nerves of the testicle, iv. 981. spermatic vessels, iv. 981. arteries, iv. 981. veins, iv. 981. absorbents, iii. 227 ; iv. 982. nerves, iv. 982. position of the testicles during the early periods of fetal existence, ii. 740. descent and development of, ii. 740. development of the, iv. 473, 474. progressive development of the vesicles of the testis of Squalus cornubicus, iv. 453. V. the testicle in the foetus, and its passage into the scrotum, iv. 982. VI. functions of the testicle, iv. 984. influence of the brain and testicles upon each other, iv. 985. 994. influence of the, in developing the general sexual peculiarities of the male, ii. 714, el seq. the testicles the only source of the fecundating power, ii. 458. quantity of semen emitted from the testicles at each coitus, iv. 1434, 1 135. envelopes of the testicle, iv. 986. superficial or external spermatic fascia, iv. 936. cremaster muscle, iv. 986. deep spermatic fascia, iv. 986. spermntic cord, iv. 986. VII. Comparative anatomy. See GENERATION, OR- GANS OF. VIII. Abnormal anatomy, iv. 986. congenital imperfections and malformations, iv. 986. numerical excesses and defects, iv. 986. supernumerary testicles, iv. 986. monorchides, iv. 987. deficiencies and imperfections of the vas de- ferens, iv. 987. origin of these defects, iv. 988. influence of these deficiencies and imper- fections on the subsequent condition of the testicle, iv. 988. imperfect transition, iv. 988. causes of failure of transition, iv. 989. abnormal conditions of the testicles in cases of spurious hermaphroditism. See UERMAPHRO- 01TISM. fatty degeneration of the testicle, iv. 96. induration of the testicle, iv. 712. passage of the testicle into the perineum, iv. 990. passage of the testicle through the crural ring, iv. atrophy of the testicle, iv. 991. 1 . arrest of development, iv. 991. 2. wasting, iv. 992. causes, iv. 992, 993. inflammation of the tunica vaginalis, or acute hydrocele, iv. 994, 995. analysis of the fluid of hydrocele, iv. 995. multilocular hydrocele, "iv. 996. hydro-sarcocele, iv. 996. congenital hydrocele, iv. 996. encysted hydrocele, iv. 997. of the epididymis, iv. 998. of the tunica vaginalis, iv. 998. occurrence of spermatozoa in the fluid con- tents of the cyst, iv. 998. probable cause of, iv. 999. diffused hydrocele of the spermatic cord. iv. 909. encysted hydrocele of the spermatic cord, iv. 1000. complications of hydrocele, iv. 1001. heematocele of the testicle, iv. 1002. encysted hscmatocele of the testicle, iv. 1003, orchitis, iv. 1004. acute, iv. 1004. chronic, iv. 1006. syphilitic, iv. 1008. tubercular disease of testicle, iv. 1008. carcinoma of the testicle, iv. 1009. GENERAL INDEX. 873 TESTICLE— continued. scirrhous disease, fv. 1009. enceptialoid cancer, iv. 1C09. colloid cancer, iv. 1010. melanosis, iv. 1010. cystic disease of the testicle, iv. 1010. < ssific deposits in the testicle, iv. 101 1. loose bodies iu the cavity of the tunica vaginalis, iv. 1011. fo?tal remains in the testicle, ir. 1011. vaiuocfle, iv. 1011. scrotum, morbid anatomy of the, iv. 1013. elephantiasis, iv. 1013. hypertrophy of the scrotum, ir. 1014. cancer scroti, or chimnev-sweeper's cancer, iv. 1014. carcinoma scroti, iv. 1015. melanosis scroti, iv. 1016. fibrous tumours of scrotum, iv. 1017. See also GENERATION, ORGANS OF. Tatmtout, a family of Reptilia. iv. 265, et seq. Testudo elephantopus, organs and mode of progression of the, iii. 450. myda-s (turtle), nervous system of the, iii. 620. Tetanus, fatal, appearances presented by ruptured muscle in. iii. 526. 529. Tethca cranium, a species of Porifera, iv. 6G, 67. lyncurium, a species of Porifera, iv. 66. Tethinm, a family ol Porifera, iv. 65. characters of the family, iv. 05. propagation of, iv. 70. Tetiabranchiata, i. 518. description of the order, i. 518. Tctraudon electricus, ii. 81. localities inhabited by the fish, ii. 83. physiological effects of its electrical discharge, il. 84. Tcttaodons, teeth of, iii. 980. mode of progression of thp, iii. 437. Tetrarhynckus, mode of reproduction of, s. 27. Ti-traspore of red Algae, or Floridea;, s 221. Tetrodon mola (moon-fish), nervous system of the, iii. 615. Tfuthidte, calamaries, i. 521. characters of the class, i. 521. Textus cellularis intermedius v. laxus, v. 510. Mrictus, i. 510. stripatus, i. 510. Thalami, optic, iii. 675. 700. corpus geniculatum, externum, iii. 700. internum, iii. 700. fibres of optic thalami, iii. 700. connexions, iii. 700. sections, iii. 701. structure, iii. 700. probably gives roots to human optic nerve, iii. 766. functions of the optic thalami, iii. 722 M. the optic thalami the centre of sensation, iii. 722 M. 723 E. Thallus of Licliens, origin of the, s. 22". Theb sins, foramina of, ii. ftSO. valve of, or lesser Eustachian valve, ii. 580 j iv. 1415. veins of, or venae minima, ii. 597 ; iv. 1415. Theca or ascus of Fungi, s. 225. 230. Theca foliiculi of Baer, s. 551. 555. Thennr eminence, ii. 358. Theodactylus, organs and mode of progression of, iii. 449. Thcorus, a genus of Rotifera, iv. 401. Thentidce, a famiiy of Fishes, iii. 9i7. Thickening of mucous membrane of nose, iii. 738. Thief, test for the discovery of a, in India, iv. 466. TAig/i, superficial fascia of the, ii. 238. Thi«h-bone.\\. 165. See Femur. Third nerve, hi. 785. 787. inferior division of the, iii. 787. branches, iii. 787. internal, iii. 787. middle, iii. 787. external, iii. 787. intercostal nerve, i. 217- ventricle of the brain, iii. 676. 704. See Ventricle. Thirst, perception of, ii. 26. causes of, ii. 26. details ol death by, 8. 3f>7. Thoracic aorta, i. 189. See AORTA. aneurism of the, i. 192. artery, iv. 818. duct. iii. 206. 579; iv. 816. detected by Eustacbius, i. 20. description of the, i. 23 ; iii. 221. lymphatics of the, iii. 229. ganglia, s. 425. nerves, i. 361. anterior, or short, i. 361 ; iv. 755. middle, i. 361. posterior or respiratory, i. 361. veins, iv. 1407. Thoracica acrornialis artery, i. 360. alaris artery, i. 358. 264. humeraria artery, i. 359. longior artery, i. 359. 361 ; iii. 249- suprema artery, i. 3-"/9, 360. 364. Supp. T7toracico-cervici\l septum, iv. 816. THORAX, iv. 1017. definition, iv. 1017. classification of respiratory movements in animals, iii. 836; iv. 1018. first kind : Infusoria, iv. 1018. second kind : Insecta, ii. 911 ; iv. 1019. table of parts, ii. 913. pro-thorax, ii. 914. meso-thorax, ii. 914. meta-thorax, ii. 915. See INSECTS. third kind : Fishes, iv. 1019. fourth kind : Amphibia, iv. 1020. fifth kind : Birds, i. 2*0 ; iv. 1021. sixth kind: Mammalia, iv. lOvl. Marsupialia, iii. 280. vertebral ribs, iii. 836. sternum, iii. 837. sternal ribs, iii. 838. in Man, iv. 1022. anatomy of the frame-work of the thorax, iv. 1022. dorsal vertebrae, iv. 1022. sternum, iv. 1022. position and size, iv. 1022. surface, anterior or cutaneous, iv. 1022. posterior (mediastmal or cardiac). iv. 10.-2. borders of the sternum, iv. 10S3. extremity, clavicular, iv. 1023. inferior, iv. 1023. connexions, iv. 1023. structure of the sternum, iv. 1023. development, or ossification of the ster- num, iv. 1023. ossification of the first piece of the sternum, iv. 1023. of the body, or the second, third, and fourth pieces, iv. 1024. union of the points of ossification of the body of the sternum, iv. 1024. ossification of the appendix, iv. 1024. ribs, iv. 1021. classification of the ribs, iv. 1025. I. general characters of the ribs, iv. 1025. surfaces, iv. 1025. borders, iv. 1025. extremities, iv. 1026. body.iv. 1026. curve, iv. 1026. arch or general 'bend of the ribs. iv. 1026. curve of torsion, iv. 1026. articulations, iv. 1027. position of the ribs, iv. 1027. structure, iv. 1027. development, iv. 1027. II. special characters of different ribs, iv. 1027. length, iv. 1028. weight, iv. 1029. torsion of the ribs (special characters), iv. 1029. surfaces (special differences), iv. 1030. specific differences of the extremities of the ribs, iv. 1030. anterior extremity, iv. 1030. posterior extremity, iv. 1030. of the head, iv. 1030. neck, iv. 1030. tubercle, iv. 1031. angle, iv. 1031. groove (specific differences), iv. 1031. costal cartilages, iv. 1031. general characters, iv. 1031. differential characters, iv. 1031. liability of the costal cartilages to ossify, iv. 1031. ligaments of the ribs, iv. 1032. with the bodies of the vertebrae, iv. 1032. with the transverse processes of two vertebrae, iv. 1032. a. the posterior costo-trar.s- verse ligament, iv. I(i32. b. the middle or inter-osseous costo-transverse liga- ment, iv. 1032. c. the anterior or long costn- transverse ligament, iv. 1032. characters peculiar to certain costo-vertebral articulations, iv. 1032. with the sternum (chondro-sternal articulation), iv. 1032. connexions of the ribs with their cartilages, iv. 1033. articulations of the costal cartilages one with the other, iv. K>:i3 ligaments of the sternum, iv. 1033. 3L 874 GENERAL INDEX. THORAX — continued. ol the thorax in general, iv. 1033. boundaries of the thoracic cavity, iv. 1034. contents of the thorax, iv. 1035. shape of the thorax, iv. 1035. external thorax, iv. 1035. anterior or sternal region, iv. 1035. posterior or vertebral region, iv. 1035. lateral or costal region, iv. 1035. internal conformation of the. thorax, iv. 1036. anterior region, iv. 1036. posterior region, iv. 1037. lateral region, iv. 1037. base of thoracic cavity, iv. 1037. conformation as affected by age and sex, iv. 1037. conformation as affected by disease and occu- pation, iv. 1038. pigeon- or chicken-breast, iv. 1039. dimensions of the thorax, iv. 1040. course of the nervus vagus through the thorax, iii. 888. lymphatics, iii. 229. of the respiratory muscles, iv. 1042. intercostal muscles, iv. 1042. external, iv. 1043. internal, iv. 1043. action of the intercostal muscles, iv. 1044. 1055. movement of the levers, iv. 1047. effect of tensions, oblique, perpendicular, and decussating, between the levers and ribs, iv. 1050. of the degree of obliquity of a tension, iv. 1052. of the obliquity of the ribs or bars with reference to the spine, iv. 1053. of oblique tensions in contrary directions, iv. 1053. of tensions at different parts of the bars or ribs, iv. 1054. levatores costarum,iv. 1055. triangularis sterni (sterno-costalis), iv. 1055. action, iv. 105"'. infra-costales, iv. 1056. action, iv. 1056. of the elasticity of the ribs, iv. 1056. of the elastic power of the lungs, iv. 1058. of respiratory muscular power, iv. 1060. the hEemadynamometer, iv. 1060. 1063. of the respiratory volumes, iv. 1064. of the volumes of air expelled from the lungs, iv. 1066. vital capacity, iv. 333. 1068. to measure the vital capacity volume of air, iv. 1068. the spirometer, iv. 1060. to determine the volume of air in the spirometer, iv. 1070. to correct the respired volume for tempe- rature, iv. 1070. affected by height, iv. 1070. by the position of the body, iv. 1073. by weight, iv. 1073. relation of vital capacity to the circumference o the thorax, iv. 1077. affected by age, iv. 1077. by disease, iv. 1078. of the respiratory movements, iv. 1079. profile view of the breathing movements in male and female, iv. 1080. of the position of the diaphragm, iv. 1081. ordinary breathing, iv. 1(82. extraordinary breathing in both sexes, iv. 10^-2. pathological respiratory movements, iv. 1083. limited breathing movement, iv. 1084. non-symmetrical breathing movements, iv 1084. reversed breathing movements,'iv. 1084. massive breathing movements, iv. 1084. interrupted breathing movements, iv. 1084. partial breathing movements, iv. 1084. quick and slow breathing movements, iv 1085. irregular breathing, iv. 1085. double breathing, iv. 1085. of the number of respirations in a given time, iv 1085. relative velocity of the breathing and the pulse iv. 1085. sudden change in atmospheric pressure, iv 1086. of the sounds of respiration, iv. 10F6. Thorax, congenital abnormal conditions, iv. 949. fissure of the thorax, iv. 949. ectopia cordis, iv. 949. Thripidce, a family of Insecta of the order Homoptera, i 868. Thrush, white (muguet of the French), iv. 118. Thumb, carpo-metacarpal articulations of the, ii. 509. abnormal conditions of the, ii. 511. T/mnny, instincts of the, iii. 13. rhy 'groma, i. 469. Tliylacinus, a genus of Marsupialia, iii. 258. characters of the genus, iii. 258. species of, iii. 258. Tfiylacinus Harrisii, or "hyaena" of VanDiemen's Land, iii. 258. Tkylacotkeritrm, dental peculiarities of the, iii. 260. Thymus artery, iv. 822. 1094. vein, iv. 101)4. THYMUS GLAND, iv. 1087. definition, iv. 1087. human anatomy, iv. 1087. relative situation, iv. 1088. structure, iv. 1089. development, iv. 839. 1089. mature contents of the gland, iv. 1090. contents of the thymic cavities, iv. 1093. vascular supply, iv. 1094. absorbent vessels, iv. 1094. nervous supply, iv. 1094. development, early, iv. 1094. of size, iv. 1095. comparative anatomy, iv. 1095. Mammalia, iv. 1095. Aves, iv. 1097. Reptilia, iv. 1098. Pisces, iv. 1099. physiology of the thymus gland, iv. 445. 1099. morbid anatomy, iv. 1101. absence of the gland, iv. 1102. inflammation, iv. 1102. tubercular disease, iv. 1102. scirrhus, iv. 1102. atrophy, iv. 1102. hypertrophy, itr. 1102. a hypothetical cause of spasmodic croup, iii. morbid conditions of the foetus in utero, ii. 331. 7%yro-arytenoid ligaments (chorda; vocales), iii. 102. 105; iv. 1479. inferior and superior, iii. 105. muscle, iii. 108. action, iii. 109. See also VOICE. TA^ro-epiglottid muscles, iii. 110. ligament, iii. 104. TA^ro-hyoid branch of ninth pair of nerves, iii. 722. ligaments, i. 251. middle, iii. 104. membrane, iii. 102. muscle, iii. 105. 563. Thyroid arteries, ii. 831 ; iv. 1106. inferior, iv. 823. origin and course, iv. 823. anterior relations, iv. 823. branches, iv. 823. a. arteria cervicalis ascendens, iv. 824. b. descending branches, iv. 824. c. terminal or thyroid branches, iv. 824. middle, ii. 851. superior, i. 485. branch to the larynx, iii. 110. axis, iv. 823. branches, iv. 823. 1. inferior thyroid artery, iv. 8 3. origin and course, iv. 823. anterior relations, iv. 823. branches of infeiior thyroid, iv. 824. «. arteria cervicalis ascendens, iv. 824. b. descending branches, iv. 824. c. terminal or thyroid branches, iv. 824. 2. supra-scapular artery, iv. 824. 3. arteria transversal is colli, iv. 824. cervicalis superficialis, iv. 824. body, iii. 575. branch of ninth pair of nerves, iii. 722. cartilage, iii. 101. cornuaof, iii. 102. tubercles of, iii. 102. THYROID GLAND, iv. 1102. definition, iv. 1102. human anatomy, iv. 1102. size, iv. 1102. weight, iv. 1102. form, iv. 1102. situations and relations, iv. 1103. colour and consistence, iv. 1103. structure, iv. 839. 1104. contents of the cavities, iv. 1105. analysis of thyroid gland, iv. 1106. vessels, iv. 1106. arteries, iv. 1106. veins, iv. 110'. lymphatics, iv. 1107. nerves, iv. 1107. development, iv. 1107. comparative anatomy, iv. 1108. Mammalia, iv. 1108. Aves, i. 348; iv. 1108. Reptiles, iv. 1108. Fishes, iv. 1 109. OENERAL INDEX. 875 THYROID GLAND — continued. morphology, iv. 1111. use, iv. 445, 1113. morbid anatomy, iv. 1114. inflammation, iv, 1114. alterations of structure, iv. 1114. hypertrophy, iv. 1114. melicerous dfgeneration, iv. 1114. bronchocele, iv. 1115. adventitious formations, iv. 1116. cysts, iv. 1116. carcinomatous growths, iv. 1116. encephaloid or scirrhus, iv. 1 hi. enlargement of the vessels, iv. 1116. morbid conditions of the thyroid gland in the foetus in titero, ii. 335. his'ory of investigations, iv. 1117. Thyroid muscle, iii. 101. or obturator, foramen, s. 11G. membrane, s. 126. veins, iv. 1107. inferior, ii. 851 ; iv. 1408. superior, iv. 1406. middle, iv. 14dfi. Tibia, or shin-bone, i. 151 ; ii. 16S ; iii. 45. development, ii. 171. extremities, ii. 1O\ 169. form and size, ii. 16S, 169. surfaces, ii. 169, 170. structure, ii. 170. spine of the tibia, ii. 168. tuberosities of the tibia, ii. 169. luxations inwards, i. 155, 156. outwards, i. 158. forwards and backwards, i. 1!>9. complete, i. 159. partial, i. 160. the most eligible situations for exposing the tibia in order to trephine, &c., iii. 136. liability of the tibia to disease, iii. 136. nodes and abscesses, iii. 136. amputations of the leg, iii. 1S4. precaution with respect to the projecting angle which the tibia, when amputated, presents an- t-riorly, iii. 135. curve of the tibia, iii. 136. fractures of the tibia, iii. 69. 136. atrophy of the, in old persons, iii. 69. Tibiat nerve, iii. 134 ; iv. 62. 7fi9. anterior, iii. 132 ; iv. 768. internal deep branch, iv. 76^. external deep branch, iv. 768. origin and course, iv. 769. muscular branches, iv. 769. branch for the plantaris, iv. 769. for the poplitaeus, iv. 769. tibialis posticus, iv. 769. flexor communis digrorum and longus pollicis, iv. 769. superior internal articular, iv. 769. cutaneous, or tibial sapha?nus iv. "7". superior and inferior calcaneal branch, iv. 770. terminal branches, iv. 770. Tibial artery, anterior, i. 150; ii.355; iii. 131. origin and course iii. 131. ligatures -if the, iii. 132. demonstrations of, iii. 132. posterior, ii.354; iii. 13x. origin and course, iii. 133. relations, iii. 133. operations for ligaturing, iii. 133. saphsnus nerve, iv. 770. veins, iv. 1411. Tibialis anticus muscle, ii. 352; iii. 131. 137. tendon, i. 149. posticus, i:i. 133. 140. nerve to the, iv. 769. TIBIO-FIBUI.AR ARTICULATION*, i 152; iv. 1118. superior tibio-fibular articulation, iv. 1118. ligaments, iv. 1118. anterior ligament, iv. 1118. posterior ligament, iv. 1118. tendon of the biceps (flexor cruris), iv. 1118. synovial membrane, iv. 1 1 18. inferior tibio-fibular articulation, iv. 1119. cartilage, iv. 1119. synovial membrane, iv. 1119. ligaments, iv. 1119. anterior ligament, iv. 11 19. posterior ligament, iv. 1119. interosseous ligament, iv. 1119. mechanism of the tibio-fibular articulations, iv. 1119. dislocation of the fibula at the upper tibio-fibular articulation, iv. 111!1. mechanism of the inferior tibio-fibular articu- lation, iv. 1119,1120. Tibio-tarsal ligament, anterior, i. 152. internal, i. 152. Tic douloureux, ii. 228. Ticks, i: Tiger, organs and mode of locomotion of the, iii. 455. Tiger — contin tied. powers of leaping of the, iii. 474. 477. organs of voice of the, iv. 1490. urine of the, iv. 1279. Tight-lacing, effects of, on the organs of digestion, s. 405. Timarcha tenebricosa, ii. 863. " Timbre " of sounds, definition of, ii. 569. of the human voice, iv. 1475. Tinnitus aurium, phenomenon of, iii. 723 B. Tipulidis, societies of, for various purposes, iii. 16. Tissue, formation of, iii. 747. homogeneous membrane and fibres formed from fibrin independent of cells, iii. 74H. development of tissues originating in cells, iii. 750. destruction of the tissues, death caused l>y, i. 791. changes in the tissues a sign of actual death, i. 804. retention of fluid in the tissues a cause of death, i. 792. Tissue, areolar, generally, iii. 494 ; iv. 513. white fibrous element of, Hi. 494. yellow fibrous element, iii. 494. areolar tissue of glands, iii. 494. of muscles, iii. 516. of stomach (or tunica nervca), s. 325. cellular, i. 367. of eyelids, iii. 82. elastic, iv. 512. ligament, i. 251. gelatinous, anaUsU of, iii, 806. inter laminar fibro-cartilagiuou?, s. 125. interstitial cellular, ii. 489. muscular or sarcous. See MUSCLE. of auricles, ii. 593. ventricles, ii. 593. osseous. See OSSEOUS TISSUE. subcutaneous cellular, i. 3*. 216. of elbow, ii. 63. foot, ii. 351. hand, ii. 524. penis, iii. 912. white and yellow fibrous, iv. 512. See SEROUS AND SYNOVIAL MEMBRANES. yellow fibrous, elasticity of the, ii. 58. Tobacco, alimentary value of the leaf of, s. 395. action of, on the vital power of the heart, i. 723. action of essential oil of, on the heart, i. 793. 797. Toes, articulations of the, ii. 343. bones of the, ii. 342. phalanges, ii. 342. See also Phalanges. abnormal conditions of the, ii. 347. corns and bunions on the, causes of, ii. 353. phalanges of toes in birds, table of the number of, i. 289. See AYES. plantar region of the, ii. 355. Tomicus topographus, its ravages among-t the trees of the Hartz Forest, ii. 862. Tonga islanders, physical characters of the, ir. 1362. TONGUB, iv. 1120. Human Anatomy, iv. 1120. size, iv. 1120. direction, iv. 1120. shape, iv. 1120. general description, iv. 1120. superior surface, iv. 1121. inferior surface, iv. 1122. edges, iv. 112-2. anterior extremity, apex, or point, iv. 1122. posterior extremity, or base, iv. 1122. basis or framework of the tongue, iv. 1 123. byoid bone, iv. 1123. relations, iv. 1123. basis or body, iv. 1123. cornua, greater, iv. 1124. lesser, iv. 1124. structure, iv. 1124. development, iv. 1124. hyo-glossal membrane or ligament, iv. 1124. median fibrous septum, iv. 1124. investments, iii. 544. 565 ; iv. 1124. muscular system, iv. 1125. intrinsic muscles, iv. 1 125. lingual, transverse, iv. 1126. vertical, iv. 1126. superior, iv. 1 126. inferior, iv. 1126. microscopical examination of thin sec- tions, iv. 1127. mode of termination of the intrinsic fibres, iv. 1131. extrinsic muscles, iv. 1132. palato glossus (glosso-staphylinus), iv. 1132. stylo-glossus, iv. 1133. hyo-glossus, iv. 1 133. genio-glossus, iv. 1133. accessory extrinsic muscles, iv. 1134. movements of the tongue, iv. 1134. intrinsic movements, iv. 1 134. as affecting its length, iv. 1131. direction, iv. 1134. extrinsic movements, iv. I 34. as affecting its length, iv. 1134 direction, iv. 1135. 3 L 2 876 GENERAL INDEX. TONGUE — continued, tegumentary system, iv. 1135. cutis, iv. 1135. basement membrane, iv. 1135. epithelium, iv. 1135. papillary structure of the tongue, iv. 860. 1126. circumvallate papillae, iv. 1136. fungiform, iv. 1137. conical or filiform, iv. 1138. simple, iv. 1139. structure of papillae, iv. 1139. functions of the different papillae, iv. 1140. • See also FIFTH NERVE ; EIGHTH NERVE ; TASTE. mucous glands, iv. 1140. vessels of the tongue, iv. 1141. lingual artery, iv. 1141. branches of the lingual, iv. 1141. hyoid branch, iv. 1141. dorsalis linguae branch, IT. 1141. sublingual branch, iv. 1 141. ranine branch, iv. 1141. nerves of the tongue, iii. 723; iv. 1141. lingual branch of the fifth, iv. 1141. glosso-pharyngeal, iv. 1141. lingual or gustatory, iv. 1141. ninth, or hypoglossal, iv. 1141. See also FIFTH NERVE ; EIGHTH NERVE ; KIN TH NERVE ; TASTE. Comparative Anatomy, iv. 1141. Insfcta, iv. 1141, 1142. Mollusca, iv. 1142. Gasteropoda, ii. 385; iv. 1142. Cephalopoda, i. 632 ; iv. 1143. rtebrata, iv. 1143. Vertebrata, hyoid apparatus, iv. 1144. in birds, iv. 1145. in Mammalia, iv. 1146. general characters of the tongue in the four classes of Vertebrata, iv. 1146. Pisces, ir. 1146. Reptilia, iv. 292. 1146. Batrachia, iv. 1146. Ophidia, iv. 1147, Chelonia, iv. 1147. Sauria, iv. 1147. Aves, iv. 1150. Mammal w, iii. 236; iv. 1151. Ruminantia, s. 532. functions of the tongue, iv. 1151. prehension, iv. 1151. mastication, iv. 1152. insalivation, iv. 1152. deglutition, iv. 1152. first stage, or oral, iv. 1152. second stage, or pharyngeal, iv. 1152. third stage, or cesophageal, iv. 1153. gpeech, iv. 1153. See VOICE. Morbid Anatomy, iv. 1 153. inflammation of the tongue, iv. 1153. suppurative glossitis, iv. 1153. erectile glossitis, iv. 1153. lingual quinsy, iv. 1154. mercurial glossitis, iv. 1 154. ulceration of the tongue, iv. 1 154. dyspeptic ulceration, iv. 1 154. small circular ulcers, iv. 1154. severe and deep-seated ulcers, iv. 1155. aphthous ulceration, iv. 1155. indurated non-malignant uiceration, iv. 1155. gangrenous ulceration, iv. 115G. syphilitic ulceration, iv. 1156. small, circular, superficial ulcers, iv. 1156. rhagades, or fissures, iv. 1156. glossy tubercle, iv. 1156. pha».edaenic ulcers, iv. 1157- cancer of the tongue, iv. 1157. scirrhtis, iv. 1157. tumours of the tongue, iv. 1157. fatty tumours, iv. 1157. encysted tumour, iv. 1157. mulberry-like tumour, iv. 1158. polypus-like tumour, iv. 1158. hypertrophy and prolapsus of the tongue, iv. 1158. atrophy of the tongue, iv. 1159. diseases of the papillae, iv. 1159. hypertrophy of papillae, iv. 1159. hairs on conical or filiform papillae, iv. 1159. contrast afforded by the tongue in scarla- tina, iv. 1160. effusions into the papilla?, iv. 1161. extravasations of blood, iv. 1161. lymph, iv. 1161. denuded papillae, iv. 1161. fur of the tongue, iv. 1161. healing and reparation of the papillary surface of the tongue, iv. 1161. tongue-tie, iv. 1 162. tongue-swallowing, iv. 1162. adhesions of the tongue, iv. 1162. necrosis of the hyoid bone, iv. 1 IG5. " Tongue, cutting the," operation of, iv. 1121. Tonic power, effects of the, on paralytic limbs, iii. 40. Toiiicity, definition of, i. 667. of arteries, i. 667. of muscles, iii. 524. Tonsillitic artery, i. 486 ; iii. 949. twigs of glosso-pharyngeal nerve, ii. 497. Tonsils or amygdalae, iii. 952; iv. 1121. vessels and nerves of the tonsils, iii. 953. calculi of the, iv. 83. Tophi, or gouty concretions, iv. 90. chemical constitution of, iv. 91. Torcitlar Herophili sinus, i. 732; iii. 631. Torpedo, species of the, ii. 81. follicular nervous apparatus of Savi, iii. 880. ganglia of the, s. 440. anatomy of its electrical organs, ii. 87, 88 ; iii. 879, 880. circumstances under which the discharge of electricity takes place, ii. 82. exhaustion from a succession of discharges, ii. 83. localities inhabited by the fish, ii. 81, 82. magnetical effects of the electrical discharge, ii. 85. motions of the fish in discharging, ii. 83. physiological effects of the discharge, ii. 83. production of sparks and evolution of heat, ii, 86. results of experiments where the nerves and electrical organs were mutilated, ii. 87. uses of the electrical function, ii. 97. See ELECTRICITY, ANIMAL. Torpor, ii. 764, 765. 768. 775. causes of, i. 416 ; ii. 768. 775. differences between torpor and hibernation, ii. 775. of hibernating animals, causes of, i. 263. Torsion of the arteries, operation of, i. 224. 228. of intestine, s. 406. Tortoise (Testudo), anatomy of the, iv. 266, et seq. muscular system of'the, iii. 542. organs and mode of progression of the, iii. 4oO. uses of its carapace and plastrum, iii. 450. land, urine of the, iv. 1281. mud, or trionyx, pelvis of the, s. 170. Torula of the human subject, iv. 144. Turulce, mode of reproduction of the, s. 224. TOUCH, iv. 1163. definition, iv. 1163. general sensibility, iv. 1163. sense of touch, iv". 1165. special organs of touch, iv. 1165. conditions of the sense of touch, iv. 1167. exercise of the sense, iv. 1 168. tactile discrimination, iv. 1168. Professor Weber's table, iv. 1169. sense of temperature, iv. 1171. muscular sense, iv. 1172. sense of weight, iv. 1175. of direction, iv. 1175. mental phenomena connected with the sense, iv. 1176. improvability of the sense of ti uch, iv. 1177. exaltation in cases of deafness and uumbness, iv. 1178-1182. morbid conditions of the sense of touch, iv. 1182. anaesthesia, or absence of sensation, iv. 1182. causes, iv. 1182. epidemic de Paris, iv. 1183. hyperassthesia, or increased sensibility to touch, iv. 1184. depravation of tactile sensibility, manifested in a variety of morbid phenomena, iv. 1184. in infancy, i. 72. sense of, in Crustacea, i. 767. in Arachnidans, i. 207. in insects, ii. 961. See INSBCTA. in birds, i. 311. See AVES. in the bat, i. 599. See CHEIROPTERA. in Cetacea, i. 589. See CETACEA. Toxodon, anatomy of the. See PACHYDERM ATA. Trabecula: of Haller, iii. 631. of penis, iii. 912. Trabecular tissue (trabeculae lienis), iv. 773. Trachea ot man, iii. 104 ; s. 258. structural anatomy, s. 259. tracheal mucous membrane, s. 259. cilia attached to the tracheal epithelium, s. 260, tracheal glands, s. 260. secretion of, s. 261. fibrous structures, s. 261. tracheal cartilaginous rings, s. 261. tracheal muscles, s. 262. arteries of the trachea, s. 262. the bronchi, s. 262. structural anatomy of the bronchi, s. 262, 263. infundibulum of Rossignol, s. 264. the bronchi divide on no constant or regu- lar plan, s. 264. contractility of the bronchial tubes, s. 264. tumours of trachea, effect of pressure of, iii. 126. sympathetic ulceration of the, in cases of tubercular consumption, iii. 119. formation of ;in artificial opening in the trachea in cases ofj-hthisis laryngea, iii. I2i. GENERAL INDEX. 877 Trachea of insects, ii. 982. See INSECTA. aquiferous, of Acalepha?, i. 44. Trachcarite, or Tracheary Arachnidans, i. 200. circulating system, i. 205. digestive sys'tem, i. 202. generative sy»tem, i. 209. respiratory system, i. 204. secretion, organs of, i. 208. sense, organs of, i. 207. subdivisions of the order into genera, table of, i 200. See ARACHMDA. Trachflinidee (neck animalcules), a family of Polygastric animals, iv. h. et sea. characters of the family, iii, 5. Tiachelius anas, iv. 13. vorax, iv. 13. TYocAf/o-mastoideus muscle, i. 373. 732. 734. TYacAfo-cricoidean articulation, iii. 104. Tracheotomy, operation of, iii. 125. Tracts of corpus callosum, longitudinal, iii. 674. 701. olivary, or fasciculi iunoiuinati of Cruveilhier, iii. 678. Tractus olfactorius, iii. 732. optici, iii. 1> -l. origin and relations, iii. 762. spiralis foraminulentus, ii. 540. 542. Tragus, ii. 550, 551. Train oil, chemical characters of, ii. 233. Transfusion of blood, operation of, i. 409. 429. Transparency and opacity of bodies, iv. 143". Transversals aodominis muscle, i. 7 ; ii. 840; s. 137. colli artery, i. 367 ; i?. 436. 824. origin and course, ir. 824. branch : cervicalis superficial, iv. 824. muscle, i. 373. fascia, ii. 8ll ; s. 13*. humeri artery, i. 367. pedis muscle", ii. 358. arch of foot, ii. 314. 357. artery of face, iii. 93 commissures of the brain, iii. 702. corpus callosum, iii. 702. anterior commissure, iii. 702. posterior commissure, iii. 703. soft commissure, ii. 703. facial arterv, iii. 903. vein, iii. 903. fascia, i. 11; ii. 231. 240. lines of sacrum, s. 118. perineal artery, iii. 929. muscle, i. 177; iii. 929 ; s. 138. plexus of veins, iv. 1410. tacral processes, s. 118. septum, ii. 538. tubercles of sacrum, s. 119. vein, iv. 1107. sulcus, ii. 538. Transrersus nasi muscle, iii. 728. relat on and action, iii. 728. Trapezium, ii. 506. articulations, ii. 506. non- articular surfaces, ii. 506. of Treviranus, iii. 681. 683. Trapeziut muscle, i. 3C9. 732 ; iv. 434, 435. 576. action of, iv. 434. Trapezoid bone, ii. 506. articulations and non-articular surfaces, ii. 506. Traumatic aneurism, i. 237. . See ANECKISM ; ARTERY. Tree-ants. See Ants. Tree-frog, pneumatic apparatus of its feet, iii. 448. Tree-hoppers (Cicadiidae), iii. 868. Trees, vitality of animals enclosed in, iii. 158. Trtmntoda, an order of Entozoa of .Kudolplii, ii. 116. 132. See ENTOZOA ; Sterelmintha. parasites with which it is infested, ii. 133. Trematoidea, digestive organs of the, s. 295. Trematoda, mode of reproduction of, s. 29. ova of, s. [124]. peculiarity in the arrangement of the reproductive organs of, s. [147]. Triangular cartilage of wrist-joint, i. 249. lo>sa, i. 216. ligament, iii. 930. of the liver, iii. 940. of urethra, iv. 1247. Triangularis nasi muscle, ii. 222 ; iii. 728. relations and action, ii. 222 ; iii, 728. Triangularis oris muscle, ii. 225. relations and action, ii. 225. Triangularis sterni muscle, iv. 1022. Triangularis sterni (sterno-coslalis.,, muscle, iv. 1055. action, iv. 1055. Triarthra, a genus of Rotifera, iv. 404. Trinrthra longiseta, iv. 409. Te&Au of the Greeks, ii. 686. Triceps muscle, i. 216. 217. 362 ; ii. 160. tendon of the, ii. 64, 65. surae muscle of Meckel, iii. 132. 139. Trichechus rosmarus, or walrus, dentition of the, iv. 916. food of, iv. 916. Trichiasis, operation for, iii. 82 Trichina spiralis, or parasite of the human muscles, Ii. 113. size and position of the cysts of the animals, ii. 1 14. microscopic appearance of, ii. 114. organisation of, ii. 115. Tricttinits within the sarcolemma of muscle, iii. 512. Trichiurus electricus, ii. 81. localities inhabited by it, ii. 82. Trichoda, or hair animalcule, iv. 13. » Trichodiante, or urn animalcules, iv. 7. Trichodiscus, or radiated disc animalcule, iv. 12. Trichoptera, an order of Inst-cta, ii. 865. characters and habits of the order, ii. 865. Tricocephalus dispar, a species of Eutozoa hominis, ii. 123. organisation of, ii. 123. 127. Tricuspid, or triglochin, valve, ii. 581. Trifacial nerve, ii. 268. See FIFTH PAIR or NEKVES. Trigeminal nerve, ii. 268. See FIFTH PAIR OF NEUVES. Trigone, or velum, of the bladder, i. 385. Trigonoccphalus, or fer-de-lance, poison fangs of, i*. Trigonum vesicaa, iv. 149. Trionyx, or mud tortoise, pelvis of the, s. 170. Triophthalmus, a genus of Rotifera, iv. 404. Trisplanchnic nerve of Chaussier, s. 423. Triton cristata (triton), nervous system of the, iii. 620. mode of reproduction of the, i. 106. Triloxide of protein, iv. 163. Trochanter major of femur, ii. 165. minor of femur, ii. 166. Trochanteric artery, posterior, ii. 248. fossa, ii. 166. Trochlea, femoral, iii. 44. humeral, ii. 65, 66. Trochlear concavity, ii. 160. fossa, i. 730. or pathetic, nerve, ii. 370. See PATHETIC NERVE. Troglodytes gorilla, or chimpanzee, dentition of the, iv. 917. niger, dentition of, iv. 917. Tropical countries, diseases of, iii, 190. Truffle, organs of reproduction of the, s. 225. Tuaryks of Sahara, characters of the, iv. 1357. Tuba Eustachii, ii. 549. See Eustachian Tube. Tuba: uteri vel Fallopiana, s. 597. See Fallopian Tube. Tuber cinereum, iii. 673. 676. 703. its relation to the optic nerves, iii. 768. ischii, eversion of the, s. 208. ossis navicularis, ii. 340. Tubera circumscripta of Farre, iii. 193. diffusa of Farre, iii. 193. characters of, iii. 193. Tubercle, or tuberculous deposit, in general, iv. 104. characters of tubercle, iv. 104. tuberculous masses, iv. 104. infiltrated tubercle, iv. 105. in lung, iv. 105. grey tubercle, iv. 105. yellow opaque tuberculous matter in, iv. gelatiniform tubercle, iv. 105. microscopical condition of the yellow tuber culous matter, iv. 105. granular substance, iv. 105. cells, iv. 105. irregular particles, iv. 105. large fat globules, iv. 105. plates of cholesterin, iv. 105. amorphous saline panicles, iv. 105. melanic cells and granules, iv. 105. semi-transparent grey granulation, iv. 105. association of, with yellow tubercle, iv. 106. round or oval dull white granulation, iv. 106. analysis of tubercle, iv. 106. mode of enlargement of tubercle, iv. 107. changes to which tubercle is liable, iv. 107. invested by a cyst, iv. 107. decay by softening, iv 107. removal of tubercle, iv. 107. by simple absorption, iv. 107. by absorption combined with so-called " transformation," iv. 108. by elimination, iv. 108. tubercular cavity of lun?, iv. 1C8. sizes of cavities, iv. 109. course and event of cavities, iv. 109. Tubercle or Tubercles in particular ; — of absorbent glands, iii. 233. of theareola, iii. 247. articular, of sacrum, s. 119. of the brain, iii. 720 E. anatomical character of the disease, iii 720 E. parts most frequently affected by, iii. 720 E. in the cranial dura mater, iii. 714. in the cranial pia mater, iii. 717. of the digestive canal, s. 419. origin and course of the tub rcle, t. 419, 4:0. of Fallopian tube, s. G20. in the heart, ii. 6:57. lachrymal, ii. 208 ; iii 783. 3 L 3 878 GENERAL INDEX. Tubercles — continued. of the liver, iii. 192. scirrhous tubercle, iii. 192. pulmonary, s. 293. seat of, s. 293. nature of the tuberculous matter, s. 293. causes of the formation of tubercle in the lungs and other organs, iii. 754. of ovary, scrofulous, s. 593. prostate gland, iv. 157. radius, ii. fiG. 163. rib, iv. 10.:6. Santorini, iii. 102. serous membranes, iv. 537. spinal cord, iii. 715. .testis, yellow, iv. 1007. thyroid cartilage, iii. 102. tibia, iii. 45. tongue, glossy, iv. 1 156. transverse, of sacrum, s. 119. uterus, s. 689.701. Tubercula, or corpora, quadrigemina, iii. 685. 767. some of the roots of optic nerves derived from, iii. 765. other purposes probably fulfilled by the tubercula quadrigemina, iii. 766. Tubercular formations in the membranes of the heart, ii. 645. meningitis, iii. 718. Tuberculous diathesis, disordered nutrition in, iii. 754. Tubtrculum Loweri, ii. 580. 594. majus of humerus, ii. 159. minus, ii. 159. ossis navicularis, ii. 505. Tuberose process, i. 732. Tuberosities of the coccyx, s. 127. of femur, iii. 44. humerus, iv. 573. ischia, s 127. tibia, ii. 169. Tuberosity, iliac, s. 117. of the ischium, s. 115. Tubes of colon, s.368. of small intestine, s. 346. of stomach, s. 320. 337. limitary or basement membrane which forms these tubes, s. 3'21. contents of these tubes, s. 321. tubes of the cardiac extremity of the dog, s. 322. tubes at the pyloric extremity of the organ, s. abnormal conditions of the tubes of the stomach, s. 412. Tubiporidce ; a family of Polypifera, iv. 20. 47. characters of the family, iv. 20. Tubiporn musica, a species of Polypifera, iv. 47. 51. Tubicolarin, a genus of Ro Tubo-ovarian ligament, s. alypi , iv. Tubular membrane of nerve, iii. 591. See NERVE. Tubularia coronata, a species of Polypifera, iv. 40. 43. mode of reproduction of, iv. 42-46. digestive organs of the, s. 296. Tubularidts, a family of Polypilera, iv. 20. 40. characters of the family, iv. 20. genera, iv. 50. tentacular apparatus, iv. 41. digestive system, iv. 41. circulation, iv. 42. reproduction, iv. 42. mode of propagation, iv. 42. ova of, s. [126]. Tubuli, ostium, ii. 538. seminiferi, iv. 978. uriniferi, iv. 241. mode of injecting the tubes, iv. 241. course and termination of the tubes, iv. 242. structure of the tubes, iv. 242. epithelium of the tubes, iv. 252. ciliary motion of the tubes, iv. 253. function of the, iv. 254. diseases of the, iv. 260, et seq. Tubulifera, a section of Insects of the order Hymenoptera, ii. 865. characters and habits of the section, it. 865, 856. Tubulus, biliary, of liver, iv. 451. communis of vestibule, ii. 538. Tufts, placental, s. 717. Tumours, method of analysing, iii. 806. Tumours, aneurismal. See Aneurism ; A RTEKY, Patholo- gical conditions of. aneurismal, of trachea or bronchi, effects of pressure of, iii. 126. angeiectoma, iv. 127. of the back, i. 3 iii. 152. 799 ; iv. 1265. artificial production of, iii. 152. in the composition of the blood, i. 410; iv. 459. Uredtn&e, organs of reproduction of the, s. 226. Uredo, organs of reproduction of the, s. 226. Ureter, or excretory duct of the kidney, iv. 235. its direction, iv. 235. relations, iv. 235. epithelium of ureter, iv. 254. motor influence of the sympathetic nerve on the, s, 466. URETHRA, ii. 423; iii. 923; iv. 1244. in Male, ii. 423; iv. 1244. direction, iv. 1244. length, iv. 1244. diameter, iv. 1245. prostatic portion, iii. 924 ; iv. 1246. membranous portion, or isthmus urethrae, iii. 925. 932; iv. 1247. triangular ligament, iv. 1247. spongy portion, ii. 145; iii. 914. 925; iv. 1248. bulb, iii. 925; iv. 1248. mucous membrane, iv. 1249. lacuna? ; lacuna magnus, iv. 1250. structure, iv. 12f>0. caput gallinaginis, iv. 1252. Cowper's glands, iv. 12o2. comparative anatomy, iv. 1253. blood-vessels of the urethra, iv. 1254. arteries and veins, iv. 1254. nerves, iv. 1254. muscles, iii. 915. 932; iv. 1530. lymphatics, iv. 1254. function, iv. 1254. development, iv. 1255. pathology, iv. 1256. congenital malformations, iv. 1256. epispadias, iv. 1250. hypospadias, iv. 1256. sometimes terminating before it reaches its usual destination, iv. 1256. sometimes the opening is altogether want- ing (atrfsia urethrae), iv. 1256. deviations in diameter, iv. 1256. diseases and accidents, iv. 1250. dilated urethra, iv. 1256. deviation of the urtthrafrom its normal direc- tion, iv. 1257. solutions of continuity, iv. 1257. lissure of the inferior part of the urethra a cause of spurious hermaphroditism, ii. 691. inflammation, iv. 1257. common causes, iv. 1257. specific causes, iv. 125*. from gonorrhoea, iv. 1258. ulceration, iv. 1259. abscesses, iv. 1259. tubercles, iv. 1259. stricture, iii. 925 ; iv. 1260. spasmodic, iii. 925 ; iv. 1260. permanent, iv. 1260. varieties of permanent stricture, iv. 1260. false passages, iv. 1261. fistula; in perinaso, iv. 12G1. causes of stricture, iv. 1262. coexistence of stone with stricture, iv. 13C2. URETHRA, male — continued. diseased lacuna?, iv. 12C2. obstruction from other causes, iv. 12G2. irritable urethra, iv. 12G3. symptoms, iv. 1263. neuralgia of the urethra, iv. 1263. in Female, iv. 1203. origin and direction, iv. 1263. muscular investment, iv, 12G3. meatus urinarius, iv. 1204. organisation, iv. 1264. arteries, iv. 1264. veins, iv. 1264. lymphatics, iv. 1204. nerves, iv. 1265. prostate gland? iv. 1265. pathology of female urethra, iv. 1265. comparative anatomy of the urethra, iv. 1207. Urethritis, iv. 1257. Uric acid, i. 47 ; iv. 1270. constitution and chemical properties of, iv. 1270. method of determining the presence of, iii. 7CO. 805. presence of, in the blood, iv. 460. calculus, iv. 77. oxide calculus, iv. 80. Urinary bladder in man, i. 377. See BLADDER OF URINE. calculi, iv. 74. See also Calculi, urinary. analysis of, iii. 806. fistulae, iv. 82. organs, parasites of the, ii. 124. in various animals. See under their headings. Ruminantia, s. 5-13. Pachydermata, iii. 873. Birds, i. 347 See AVES. Fishes, iii. 1011. Insects, ii. 975.. See INSECTA. URINE, i. 127; iv. 1268. definition, iv. 1208. constituents of healthy urine, iv. 1269. urea, iv. 1209. extractive matters of urine, iv. 12G9. animal extractive matter soluble in water only, iv. 1269. colouring matters, iv. 1270. haemaphasin, iv. 1 270. uroerythrin, iv. 1270. mucus, iii. 4s2. See Mucus, uric or lithic acid, iv. 1270. hippuric acid, iv. 1270. lactic acid, iv. 1270. quantitative composition of healthy urine, iv. 1271. physical characters of healthy urine, iv. 1271. Liebig's theories on the variations caused in the urine by various ingesta, iv. 1273. changes in, when retained long in the bladder, i. 387. of animals, iv. 1279. lion, tiger, and leopard, iv. 1279. horses, iv. 1279. oxen, cow, iv. 12«0. elephant and rhinoceros, iv. 1230. camel, iv. 1280. pigs, iv. 12SO. goat, iv. 1280. beaver, iv. 1280. rabbits and guinea-pigs, iv. 1281. hare, iv. 1280. birds, iv. 1281. rattle-snake, iv. 1281. bull-frog, iv. 1281. land-tortoise, iv. 1281. urine in disease, iy. 1281. human urine, iv. 1281. lithic acid deposits, iv. 1282. deposit of lithates, iv. 1282. earthy phosphates, iv. 1283. oxalate of lime, iv. 1283. cystine, iv. 1283. carbonate of lime, iv. 1283. hippuric acid in disease of the urine, iv. 1283. calculi, iv. 1284. table of the relative frequency of the different kinds of urinary calculi in various countries, iv. 1284, 1285. lithic acid calculi, iv. li'87. mulberry, or oxalate of lime, calculi, ir. 1287. cystic oxide calculi, iv. 1287. phosphatic calculi, iv. 1287. alternating calculi, iv. 1288. mixed or compound calculi, iv. 1288. diseased conditions of urine, iv. 1289. febrile urine, iv. 1289. febrile urine, strictly speaking, iv. 1289. febril*- urine, with debility, iv. 12R9. febrile urine containing the natural proportion of water, iv. I:is9. GENERAL INDEX. 881 Urine — anaemic urine, iv. 12^0. true anaemic urine, iv. 1289. concentrated anaemic urine, iv. 1289. alkaline urine, iv. 1289. urine nearly normal, iv. 1289. itate of the urine as it is observed in different diseases, iv. 1290. pericarditis, iv. 1290. phlebitis uterina, iv. 1291. meningitis, iv. 1291. encephalitis, iv. 1291. delirium tremens, iv. 1291. mjvlitis, iv. 12'Jl. bronchitis, iv. 1291. pneumonia, iv. 1291. pleuritis, iv. 1291. empyema, iv. 1291. hepatitis, iv. 1291. nephritis, iv. 1291. arthritic, iv. 1291. chronic, iv. 1'J'Jl. albuminous, iv. 1291. morbus Briahtii, iv. 1291. cystitis, iv. 12 •>. typhus, iv. 1292. intermittent fever, iv. 1292. cholera, iv. 1292. rheumatism, iv. 1293. phthisis, iv. 1293. struma, iv. 1293. diabetes mellitus, iv. 1293. iusipidus, iv. 12!»3. chylosus, iv. 1*93. jaundice, iv". 1293. urine of pregnancy, iv. 1294. foreign substances in the urine, iv. 1294. muscular action in the expulsion of the, iii. 721 H. influence of the spinal cord upon the secretion of urine, iii. 721 S. method of analysing urine, iii. 807, healthy urine, iii. 807- diabetic urine, iii. 808. albuminous urine, iii. 809 quantity passed in twenty-four hours, ii. 149. effects of the suppression of the excretion of, ii. 150. state of the urine in cases of paraplegia, iv. 4G7. effusion of urine into the cellular tissue, i. 516. causes, i. 516. effects, i. 516. characters of urine expelled by patients suffering from spinal disease, iii. 721 S. difficult micturition, and retention of urine, the result of cystic disease of the prostate gland, iv. 158. disease of the kidney from retention of urine, iv. 256. dL.betic urine, condition of, iv. 99. theories of the pathology of diabetes, iv. [9. farty matters excreted in the urine, iv. 97. casein in combination with fat in "milky urine," iv. 94. fibrin as an adventitious product in urine, iv. 93. phosphoric acid in urine, iv. 80. albuminaria, or albuminous urine, iv. 91. albumen in the secretions, iv. 91. albuminaria from an unnatural state of the blood, iv. 91. frum morbid states of the gcnito-urinary organs, iv. 92. from accidental admixture of genital pro- ducts, iv. 92. from a doubtful cause, iv. 93. Urolenzoic, or hippuric, acid, iii. 800. analysis of, iii. 800. Urocerictee, or boring- Hies, ii. 865. Vn'dela, an order of Amphibia, i. 91, et scq. characters of the order, i. 91. Vroerythrin, iv. 1270. Urotnelia, iv. &f,4. L'ro/ioietic system of Mollusca, iii. 366. L'rous acid calculus, iv. 80. Urson ( Hystrix dorsata), anatomy of th-, iv. 377, el seq. Ursiu Malayanus, organs of voice in the, iv. 14»9. Uterine arteries, ii. 831 ; s. 552. plexus of veins, iv. 1412. of nerves, s. 430. UTERUS AND ITS APPENDAGES, s. 547. Ovary, s. 547. normal anatomy, s. 547. form, s. 547. dimensions and weight, s. 547. position and connexions, s. 548. component parts ; 1. protecting parts or tunics, s. 548. peritoneum, tunica albuginea, s. 548. 2. parenchyma or stroina, s. 5-J9. 3. Graatian vesicles, s. 550. 4. blood-vessels and nerves, s. 552. functions of the ovary, s. 552. developmental changes in the ovicapsulps, and process of emission of ova, s. 552. 1st stage: origin of the ovicapsules, s. UTERUS AND irs APPENDAGES, ovicapsules — continued. 2nd stage: growth, maturation, and pre- paration for dehiscence, s. 555. 3rd stage : rupture or dehiscence, and escape of ova, s. 558. 4th stage: decline and obliteration of the ovicapsules, s. 561. A. without impregnation, s. 561. B. after impregnation, s. 5G3. spontaneity of the emission of ova, s. 566. nature of the corpus luteum, s. 564. 5C9. classified arrangement of all the conditions which the Graafian follicle exhibits during evolution and involution, s. 570. summary of the conclusions which these con- ditions afford with reference to questions in obstetric and forensic medicine, s. 571. development and involution of the ovary, s. 571. origin of the ovary, and the alterations u liich it undergoes at different periods of life, s. 571. abnormal anatomy of the ovary. effects of extirpating the ovary, s. 57.1. deficiency and arrest of development, s. 573. atrophy and hypertrophy, s. 573. displacement, hernia, s. 573. . diseases of the tunics : inflammation, s. 574. ulceration, rupture, s. 574. hypertrophy, calcification, s. 574. ' diseases of the proper tissues : hyperaemia, s. 576. inflammation, s. 576. suppuration, s. 575. simple, multiple, multilocular, and pro- liferous cysts, s. 578. contents of ovarian cysts, s. 582, fluid contents of cysts, s. 582. quantity and rate of effusion, s. 582. composition of the fluids contained in ova- rian cysts, s. 583. hydatids, s. 684. solid contents of ovarian cysts ; sebaceous and sudoriparous glands ; fat ; hair ; teeth ; true bone, s. 584. origin of the solid contents of cysts, s, 586. foetus contained in the ovary (?) ; the question of o\ arian gestation considered, 8.586. examples of supposed ovarian gestation, solid enlargements of the ovary, s. 591. cartilaginous and ossific formations, s. 591. cancer, colloid or alveolar ; medullary and scirrhous, s. 591. scrofulous tubercles, s. 593. Parovarium, s. 593. structure and development, s. 593. abnormal states, s. 597. Fallopian Tube, or Oviduct, s. 597. normal anatomy, s. 597. form ; dimensions, s. 597. situation and connexions, s. 598. separate parts and divisions, s. 599. internal orifice, s. 699. uterine portion of the tube, s. 600. ; canal, s. 600. external orifice, s. 600. pavilion or infuudibulum, s. 601. fimbriae, s. 601. tuoo-ovarian ligament, s. 602. structure of the coats or tunics, s. 603. blood-vessels and nerves, s. 604. functions of the Fallopian tube, s. 605. reception and transmission of ova and sper- matic fluid, s. 605. first steps in the process of impregnation, s. 603. changes which the ovum undergoe- in the tube, s. 6()9. development of the Fallopian tube, s. 613. formation of the oviduct out of the duct of Muller, s. 613. abnormal anatomy of the Fallopian tube, s. 613. defect and imperfect development, s. 614. peculiarities of construction, s. 615. displacements, s. 61 ti. obli eratit.n of the canal, s. 617. hyperaemia ; inflammation, s. 617. collections of fluid within the tube ; blood ; serum ; pus, s. 617. cysts, s. 620. fibrous tumours, s. 623. tubercle ; cancer, s. 620. rupture of the tube walls, s. 620. Fallopian tube gestation; various forms, s. BUI Uterus, s. 623. noi mal anatomy s. 623. situation and position, s. 623. form, s. 624. 882 GENERAL INDEX. UTERDS AND ITS APPENDAGES, uterus — continued. dimensions and weight, s. 624. regional divisions ; fundus ; body ; cervix, s. 624. external surface, s. 626. internal surface, and cavities of the body and cer- vix, s. 626. structure and arrangement of the tissues compos- ing the body of the uterus, s. 630. peritoneal coat, iii. 944 ; s. G31. middle or muscular coat ; composition; course of the muscular fibres, s. 631. mucous or deciduous coat; composition, s. 635. utricular glands or follicles, s. 636. structure and arrangement of the tissues compos- ing the cervix uteri, s. 638. muscular coat, s. 638. mucous coat; epithelium, s. 638. papillae, s. 639. mucous follicles, s. 610. blood-vessels of the uterus, s. 640. uterine artery, ii. 831. lymphatics, s. 641. nerves, s. 641. ligament of the uterus, s. 705. broad ligament, iii. 943 ; s. 705. utero-sacral ligament, s. 705. utero-vesical ligament, s. 705. round, or sub-pubic, ligament, s. 705. development and metamorphoses of the uterus at diffe- rent periods of life, s. 642. a. origin of the uterus, and its condition during foetal life, s.642. b. the uterus from the time of birth to puberty, s. 643. c. the uterus during menstrual life, s. 644. d. the uterus during gestation ; the gravid or fully developed uterus, s. 644. size and weight, s. 645. alterations during gestation in the form of the body and cervix uteri, s. 645. position, actual and relative, of the uterus during gestation, s. 647. alterations in the special coats and tissues, s. 649. peritoneum, s. 649. muscular coat, s. 649. blood-vessels, s. 65!. nerves ; the question of enlargement of the uterine nerves during pregnancy, s. 651. mucotis or lining membrane of the uterus : development into the decidua ; decidua yera and reflexa, ii. 455 ; s. 652. histology of the decidua, s. 657. e. the uterus after parturition, ii. 454 ; s. 658. time at which the ovum arrives in the uterus after sexual union, ii. 453. the process of involution of the gravid uterus, s. 658. changes in dimensions and weight, s. 658. metamorphosis and restoration of the compo- nent tissues, s. 659. /. the uterus after the menstrual epoch ; senile atrophy or involution of the uterus in advanced life, s. 661. functions of the uterus, s. 662. a. office of the uterus in menstruation, s. 662. periods of duration and recurrence of this function, s. 662. quantity, s. 663. nature of the catamenial discharge, s. 663. composition of the menstrual fluid ; analysis, s. 663. microscopic examination, s. 663. unmixed menstrual fluid ; analysis, s. 664. source of the menstrual flux, s. 66"'. means by which the blood escapes during healthy menstruation, s. 6S5. purpose of menstruation, s. 666. relation of this function to the maturation and emission of ova examined, s. 607. purpose of the flux, s. 670. b. office of the uterus in insemination, s. 671. c. office of the uterus in gestation, s. 672. d. oflice of the uterus in parturition, s. 672. general sketch of the labour process, s. G72. peristaltic action of the uterus, and its cause, s. 673. rhythmic action of the uterus, and its cause, s. 674. influence of the different nervous centres upon the uterus in parturition, ?. 675. exciting cause of labour, s. 677. abnormal anatomy of the uterus, s. 678. defective development, s 678. 1st class : congenital defects, s. 678. the various abnormal forms of the uterus, arising from imperfect coalescence of the primitive uterine halves (commonly termed double uterus), arranged in four groups : UTERUS AND ITS APPENDAGES, uterus — continued. Group 1. uterus bipartitus, s. G78. Group II. uterus unicornis, s. 679. Group III. uterus bicornis, s. 679. Group IV. uterus bilocularis, s. 680. 2nd class : incomplete development at the time of puberty. the pre-pubertal uterus, s. 681. anomalies of form of the uterus, s. G82. antiflexion, 8. 682. retroflexion, s. 683. lateral inflexion, s. 683. anomalies of position of the uterus, s. 683. obliquity, s. 683. anti- and retro-version, s. 683. hernia of the uterus, s. 684. prolapsus, s. 684. a cause of spurious hermaphroditism, ii. 690. elevation, s. 684. inversion, s. 684. anomalies of the size of the uterus, s. 686. atrophy, s. 686. hypertrophy, s. 687. pathological conditions of the separate tissues of the uterus, s. 687. 1. pathological conditions of the peritoneal coat ; acute and chronic metro-peritonitis, s. 687. 2. pathological conditions of the subperitoneal fibrous tissue ; peri-metritis, s. 688. 3. pathological conditions of the muscular coat, s. 689. diminished and increased consistence, s. 689. parenchymatous inflammation ; metritis, s. 689. fibroid, or fibrous tumour of the uterus ; interstitial, sub-peritoneal, and sub- mucous fibroid; fibrous and muscular " polypi," s. 689. 4. pathological conditions of the mucous coat, s. 692. simple hypertrophy ; dysmenorrhceal mem- brane, s. 692. hypertrophy of the follicular structures of the uterine mucous membrane ; follicu- lar " polypi ; " mucous "polypi ;" cysts, s. 692. hypertrophy of the filiform papillae of the cervix (pseudo-ulcer), s. 61)3. simple inflammatory hypertrophy, with extroversion of the cervical mucous membrane (pseudo-ulcer), s. 693. catarrhal inflammation of the mucous coat of the uterus ; endometritis ; leucorrhcea, s. 694. ulceration of the mucous coat ; erosion, abrasion, and excoriation, s. 694. distensions of the uterine cavity, s. 697. hydrometra, s. 697. haamatometra, s. 697. physometra ; tympanites uteri, s. 698. hydatids, s. 698. narrowing and obliteration of the uterine cavity, s. 698. atresia of the os uteri, cervical canal, and cavity of the uterine body, s. 6!»8. pathological conditions involving several of the uterine tissues, s. 698. cancer, s. 699. cancroid; epithelial cancer; cauliflower excre- scence, s. 700. corroding ulcer, s. 700. tubercle, s. 701. solutions of continuity ; rupture; perforation, s. 701. pathological conditions of the uterus after parturi- tion : irregular contraction ; hourglass contraction (arrested peristaltic action), s. 702. incomplete and retarded involution, s. 702. puerperal inflammation, s. 702. endo-metritis, s. 702. metro-phlebitis, s. 703. metro-peritonitis, s. 703. blood dyscrases, s. 704. uterine calculi, iv. 86. saline depositions, iv. 00. softening and induration ot the, iv. 712. cystoides, iv. 151. masculinus. See VESICULA PROSTATICA. Ligaments of the uterus, s. 705. normal anatomy, s. 705. the broad ligament, s. 705. the utero-sacral ligaments, s. 705. the utero-vesical ligaments, s. 705. the round or sub-pubic ligaments, s. 705. Vagina, s. 706. normal anatomy, s. 706. dimensions, s. 706. external surface, s. 706. GENERAL INDEX. UTERUS AND ITS APPENDAGES, vagina — continud. composition, s. 706. internal surface, s. 706. arteries; veins; lymphatics; nerves, s. 707. uses of the vagina, s. 707. abnormal anatomy, a. 707. anomalies of form and size, 3. 707. displacements, s. 707. solutions of continuity, s. 707. inflammation, s. 707." epithelial desquamation, s. 707. serous and sanguineous infiltration, s. 707. abscess ; ulceration ; gangrene, s. 70S. cysts and tumours, s. 708. cancer, s. 70%. External organs of generation, 8. 708. normal anatomy, s. 708. the mons veneris, s. 708. labia, s. 708. clitoris, s. 709. nympha?, s. 710. vestibule, s. 710. vagina! orifice and hymen, s. 710. origin, varieties, and signification of the hymen, s. 710. sebaceous and mucii>arous "lands and follicles of the vulva; vulvo-vaginal gland, s. 711. bulb of the vagina; pars intermedia; con- strictor vaginas, s. 712. blood-vessels and nerves of the external or- gans, s. 713. abnormal anatomy, s. 714. labia, s. 714. clitoris, s. 714. nymphae and vestibule, s. 714. hymen and ostium vagina?, s. 715. Placenta, s. 715. normal anatomy, s. 715. form, s. 715. dimensions and weight, s. 715. foetal surface ; amnion ; chorion ; foetal blood- vessels, s. 715. uterine surface, s. 716. circumference, s. 716. substance, s. 717. tufts and villi, s. 717. termination of the foetal vessels, s. 718. decidun, s. 718. terminations of the maternal vessels, s. 719. development of the placenta, s. 719. of the fcetal portion, s. 719. of the maternal portion, s. 720. functions of the placenta, s. 721. Utero-gcstation, varieties in respect to, and the develop- ment of the young, ii. 430. See OVUM. Utero-vesical ligaments, s. 705. sacral ligaments, s. 705. Utricular glands or follicles of uterus, s. 63G. Utriculus prostaticus, iv. 151. 1252. development of, iv. 153. See VESICULA PROSTATICA. Uvea, or spherical choroid membrane, ii. 178. See Choroid coat, or iris, ii. 182. See 7m. flocculent growth of the, in the horse, iii. 93. Uvula, \. 3S5, 3sti ; iii. 951. vcsicae, iv. 147. Vacuum produced by the suckers of the feet of the house- fly, iii. 443. by limpets, iii. 445. Vagina, s. 706. normal anatomy, s. 706. dimensions, s. 706. external surface, s. 706. composition, s. 706. internal surtace, s. 706. arteries ; veins ; lymphatics ; nerves, s. 70G, 707. atrium vaginae, vestibulum, iv. 1425. peritoneum of the, iii. 944. sensibility of the lower part of the, ii. 447. uses of the vagina, ii. 447 ; s. 707. abnormal anatomy, s. 707. anomalies of form and size, s. 707. displacements, s. 707. solutions of continuity, s. 707. inflammation, s. 707. epithelial desquamation, s. 707. serous and sanguineous infiltration, s. 707. abscess ; ulceration ; gangrene, s. 708. cysts and tumours, s. 708. cancer, s. 708. false vagina. See HERMAPHROIMTISM. calcareous accumulations in the vagina, iv. 8G. Vayinee vasorum, iv. 772. 788. Vaginal artery, ii. 831. branches of hepatic duct, iii. 169. artery, iii. 171. branches of portal vein, iii. 1<>7. Vaginal — continued. foursa?, de«-p, i. 468. orifice, s. 710. hymen, s. 710,711. glands and follicles, s. 711. bulb of the vagina, s. 712. pars intermedia, s. 712. constrictor vaginae, s. 712. varieties in the condition of the vagina, s.710. 715. plexus of veins, iii. 167 ; iv. 1412. process, L 734. veins, iv. 1414. Vasinitis, s. 707. Vagus nerve, iv. 546. 815, 816. See PAR VAHUM. I'algus, anatomical characters of, ii. 348, 319. Valley, or vallecula, of Haller, iii. H8S. I'alsalva's sinuses of the aorta, i. 189. Valve, Eustachian, ii. 580. ileo-caecal or ileo-colic, ?. 363. of Thebesius,or lesser Eustachian valve, ii. 580; iv. 1415. of Vieussens, iii. 678. 686. 690. of the heart, diseases of the, ii. 646. atrophy of the, ii. 647. chronic endocarditis, ii. 646. dilatation of the valves, ii. 647. ossification, ii. 647. osseous deposits, ii. 647. malformations of the, ii. 633. See also HEART. of the lymphatics, iii. 209. of the rectum, iii. 921. semilunar or sigmoid, of arteries, i. 223. venous, structure of, iv. 1377. 1379. Harvey's description of, iv. 1377. different forms of valves, iv. 1378. epithelium of valves, iv. 1379. fibrous lamina, iv. 1379. sinuses in the walls of veins, iv. 1380. office of the valves, iv. 1381. functions of the sinuses, iv. 1381. morbid anatomy of the valves, iv. 1400. See VENOUS SYSTEM. Valvula coli, action of the, iii. 721. L. foraminis ovalis, vestigium foraminis ovalis, ii. .080. triglochis v. tricuspis, ii. 581. Valvulce conniventes, s. 346. Van Diemen's Land, the " hyaena " of, Iii. 258. Vanessa urticae, or common "nettle-butterfly, ii. 876. 962. Vapour, escape of, from the human body, iv. 842. Varanus crocodilinus, teeth of, iv. 894. Vurices of the anal veins, i. 185, 186. of the arteries and veins of the urinary bladder, i. 402. of the capillaries of the integuments oi' the leg, iii. 128. of veins of the leg, iii. 128. causes, iii. 129. Varicocele, iv. 1011. 1399, causes of, iv, 1309. Varicose aneurism, i. 242. See ANEURISM; ARTERY, Pathological conditions of. nerve tubes, iii. 592. causes of, iii. 593. veins, iii. 129 ; iv. 1397. varices of the leg, iv. 1398. varicocele, iv. 13i>9. haemorrhoids, iv. 1399. pathological conditions of varicose veins, iii. 129. varicose veins of the leg, caust-s of, iii. 128, 129. distension of the veins of the leg and foot, ii. 351. about the anus, i. 185. ulcers, iii. 129. treatment of, iii. 130. Varicosities of the absorbent vessels, iii. 233. VARIETIES OF MANKIND, iv. 1294. I. distinctive characteristics of man, iv. 1294. his two hands, iv. 129J. erect attitude, iv. 1295. cranium, iv. 129-T. position of the face, iv. 1296. vertebral column, iv. 1296. length of lower extremities, iv. 1296. biped progression, iv. 1279. knee-joint, iv. 1279. arched form of the foot, iv. 1207. form of the trunk, iv. 1297. visceral apparatus, iv. 1297. conformation of the brain, iv. 12G9. his senses subordinated to his intelligence, iv. 1300. capacity for intellectual progress, iv. 1300. II. species and varieties, zoologically considered, iv. 1301. diversities of age have led to the establishment of species which have no existence in nature, iv. 1302. influence of external conditions in modifying the conformations both of plants and ani- mals, iv. 1303. tendency to spontaneous variation exists in many races, iv. 1304. III. general survey of the diversities, in physical and pffcbieal characteis, presented by different races of mankind, iv. 1315. 884- GENERAL INDEX. VARIETIES OF MANKIND, general survey — continued. anatomical differences by which the several races of mankind are distinguished from each other, iv. 1319. 1. conformation ol the cranium, iv. 1319. prognathous type, iv. 1321. pyramidal type, iv. 1322. oval or elliptical type iv 1323. 2. conformation of the pelvis, iv. 1331. 3. conformation of the other parts of the skeleton, iv. 1331. 4. colour of the skin, iv. 1333. constancy of the relation between climate and complexion, iv. 1335. historical evidence of an actual change of complexion in tribes or races that are known to have migrated from one locality to another, or to have changed their mode of life, iv. 1336. 5. colour, texture, and mode of growth of the hair, iv. 1337. physiological conformity or diversity of the several races, iv. 1339. average duration of life, iv. 1339. epoch of the first menstruation, iv. 1339. frequency of the catamenial flux and the epoch of life to which it ex- tends, iv. 1341. duration of pregnancy, iv. 1341. fertility of hybrid races, ir. 1341. psychical comparison of the various races of mankind, iv. 1342. philological evidence of a common origin, in language, iv. 1345. aptotic type, iv. 1346. agglutinate type, iv. 1346. amalgamate type, iv. 1346. anaptotic type, iv. 1346. principal groups of various languages, iv. 1347. IV. general survey of the principal families of man- kind, iv. 1348. European nations, iv. 1348. Asiatic nations, iv. 1348. African nations, iv. 1352. American nations, iv. 1358. Oceanic nations, iv. 1361. general recapitulation, iv. 1363. addendum on the causes of the tendency to extinction in the races of aborigines, iv. 1365. Varir, aneurismal, i. 241. See ANEURISM; ARTERY, Pathological conditions of. Varus, ii. 348. Vas deferens artery, iv 983. deficiencies and imperfections of the, iv. 987. ejaculatorium, iv. 147. Vasa brevia, i. 195; iv. 1414; s. 327. efferentia, iii. 208. 231. of epididymis, iv. 979. deferentia, i. 380 ; ii. 457, 458 ; iii. 922 ; iv. 1431. inferentia or afferentia, iii. 207. 231. pampiniformia, iv. 982. vasorum, i. 223 ; iii. 233 ; iv. 1381. Vascular branch of nervus vagus, iii. 887. raini carotici, iii. 887. ramus ad divisionem arterize carotidis, iii. 887. rami vasculares posteriores et interni, iii. 887, anteriores et interni, iii. 887. Vascular system. See CIRCULATION. Vasculum aberrans, iv. 980. V asco-cellular structure of penis, iii. 913. Vastus externus muscle, iii. 44. interims, iii. 44. nerves for, iv. 763. Valeria Indica, tallow- like fat of the, i. 58. Vaucheriacece, mode of reproduction of the, s. 216. Vault. See Fornix. of the flancs of Crustacea, i. 757. Vegetable fibrin, iv. 169. casein, iv. 169. albumen, iv. 1si-vertebral of Breschet, iii. 630. of brain, iii. 704. of bones, i. 436. brachio-cephalic, ii. 851 ; iv. 1408. of brain, iii. 704. bronchial, i. 366; ir. 1409. GENERAL IN7DEX. 885 J'eint — continued. buccal, iv. 1404. cardiac, great, iv. 1414. posterior, iv. 1414. cephalic, i. 216. 359, 360 ; ii. 63 ; iii. 249 ; iv. 1407. median, iv. 1407. cerebral, iv. 1382. ophthalmic, iii. 94. coronaria ventriculi, ir. 1414. coronary, great, ii. 596; iv. 1404. 1414. smaller posterior, ii. 597 ; iv. 1415. anterior, ii. 5l>7 of clitoris, 8. 709. 713. of cranium, i. 748, 749. crural anterior, ii. 838. circumflex, iv. 1407. ilii, iv. 1411. internal, iv. 1412. dental, inferior, iv. 1405. of diaphragm, ii. 4. dorsal of clitoris, s. 709. of penis, iii. 933; iv. 1254. dorsi-spinal, iv. 1410. of dura mater, iii. 629. of ear, ii. 566. external, ii. 566. of elbow, ii. 63. emulgent or renal, iv. 236. 238. epigastric, superficial, iv. 1411, 1412. deep, iv. 1412. epiploic, iv. 1414. from eyelids, iii. 94. facial, ii. 227; iv. 1382. 1404. 1406. transverse, ii. 228 ; iii. 933. deep, or alveolar, iv. 1404. ophthalmic, iii. 94. of Fallopian tube, s. 6 3. femoral, superficial, ii. 238; iv. 1412. of foot, dorsal, ii. 351. plantar, ii. 355. of fore-arm, ii. 361. frontal or vena praeparata, i. 748 ; iv. 1404. of Galen, iv. 1415. gastric, iv. 1414; s. 325. gastro -epiploic, right, s. 3'27. 381. left, s. 327. gluteal, ir. 1412. hsemorrrioidai,iii.933; iv. 1412. inferior, iv. 1412. superior, iv. 1412. of hand, deep, ii. 526. superficial, ii. 526. of heart, iv. 1414, hepatic, iii. 172; iv. 1414. iliac, external, ii. 838 ; iv. 1412. internal, iii. 933, 934 ; iv. 1412. common, right, iv. 1412. left, iv. 1412. collateral, iv. 1412. infra orbital, iv. 1404. innominata, iv. 1408. right, iv. 1408. left. iv. 1408. collateral, iv. H08. intercostal, i. 365 ; iv. 1409. left superior, iv. 1409. interlobular, iii. 167. 173; iv. 1414. interosseal, palmar, iv. 1407. intestinal, s. 3«0. intra-lobular, iv. 1414. jugular, anterior, i 732 ; iii. 571. 579. internal, iv. 815, 816. 1406. external, ii. 227 ; iii. 571. 903 ; iv. 1405. of knee-joint, iii. 48. laryngeal, iv. 1406. of leg, iii. 128. lingual, iv. 1406. lobular, iii. 168. lumbar, iv. 14i3. mammary, iii. 216. 249; iv. 823. 14C8. masseteric, iv. 1404. maxillary, iii. 903. 949; iv. 140?. median, "ii. 63. 362. 524. basilic, ii. 23. 361,382. cephalic, ii. 64, 361. 362. of memhranous labyrinth, ii. 543. meningeal, middle, iv. 1405. mesenteric, superior, iv. 1414 ; s. 3S1. inferior, iv. 1414. nasal, iii. 734. obturator, iv. 1412. occipital, iv. 1405, 1406. oesophageal, s. 326. ophthalmic, ii. 228 ; iii. 786. cerebral, iii. 94. facial, iii. 94. ovarian, iv. 1413. palatine, iv. 1414. palpebral, iv. 1411. pancreatic, iv. 1414 ; s. 86. pancreatico-duodenal, s. 381. of parotid region, iii. 903. t'eins — continued. of penis, iii. 917 ; iv. 1254. dorsal, iii. 933; iv. 1254. of perineum, iii. 933. pharyngeal, iii. 949 ; iv. 1406. phrenic, iv. 1413. plantar, ii. 355. deep, internal, iv. 1411. external, iv. 1411. popliteal, i. 242 ; iii. 128 ; iv. 1411. portal, iii. 167 ; iv. 250. 1382. 1414 ; s. 381. primitive, right, ii. 828. profunda, iv. HI 2. pterygoid, iv. 1405. pubic, superficial, iv. 1411. pudic, iv. 1412; s. 714. pulmonary, ii. 581, 582; 8. 274. pyloric, superior, s. 327. 381. rachidian, iv. 1404. 1409. radial, ii, 63. 362 ; iv. 1406. ranine, iv. 1404. of rectum, i. 181. renal, iv. 236. 238. 1413. sacral, middle, iv. 1409. lateral, iv. 1409. salvatella, iv. 1407. satellite, of gustatory nerve, iv. 1404. of scapular region, iv. 437. sciatic, iv. 1412. saphena, i. 15. 148 ; ii. 238 ; iv. 61. internal, or long, iv. 1411. cutaneous and communicating branches,! v.l 411. posterior, or external, iv. 1411. major, ii. 351 ; iii. \^8. minor, ii. 851 ; iii. 128. spermatic, iv. 981. 1413. spinal, iii. 657; iv. 1404. 1406. 1409. superficial, or extra spinal, iv. 1409. deep, or intra-spinal, iv. 1409. posterior deep, iv. 1409. :, iv. 788. 1414 ; s. 381. splenic, stomach, s. 325. snbclavian, iii. 578. 817; iv. 815. 1407. subcutaneous of elbow, ii. 63. sublobular, iii. 173; iv. 1414. submeittal, iv. 1404. subscapular, iv. 1407. superficial, of neck, iii. 571. of supra-renal capsules, Iv. 833. supra-orbital, iv. 1404. sural, iv. 1411. temporal, iii. 903; iv. 1405. deep, iv. 1405. temporo-maxillary, iv. 1405. communicating branch from the, iv. 1405. of Thebesius, or venae minima, ii, 527 : iv. 1415. thoracic, iv. 1407. thyroid, iv. 1407. inferior, ii. 851 ; iv. 1408. superior, iv. 1406. middle, iv. 1406. tibial, iv. 1411. transverse, iv. 1107. facial, ii. 127 ; iii. 933. ulnar, ii. 63 ; iv. 1407. umbilical, iii. 936 ; iv. 1374. of urethra, iv. 1254. in female, iv. 1264. of urinary bladder, i. 386. uterine, s. 641. vaginal, iv. 1414; s. 706. vasa brevia, iv. 1414. vesical, i. 387; iv. 1412. vertebral, iv. 815. 822. 1406. 1408. ofvilli of intestine, s. 352. Velella limbosa, mode of progression of the, iii. 433. Velocity, in insects and birds. See MOTION, ANIMAL. of the camel, iii. 454. of fishes, iii. 438. See MOTION, ANIMAL. of the hare, iii. 453, 454. of predaceous insects, iii. 443. of some species of Quadrumana, iii. 456. of sound. See Sound. J'clum interpositum, iii. 635. 676. palati, iii. 951. or trigone, of the bladder, i. 385. posterior medullary, iii. 690. Vena alba thoracis of Kustachius, iii. 206. cava, i. 11; ii. 828. superior, ii. 5<»0; iv. 1404. 1408. veins which form the, iv. 1404—1410. inferior, or vena cava ascendens, ii. 579, 580 : IT. 1411. 1413. origin, course, aid relations, ir. 1413. dilatations, iv. 1413. collateral branches, iv. 1413. renal veins, iv. 1413. spermatic veins, iv. 1413. ovarian veins, iv. 1413. lumbar veins, iv. 1413. inferior phrenic, iv. 1413. nerves of, iv. 1382. 886 GENERAL INDEX. Vena cava — continued, anastomoses of vena cava and portal vein, iii. 176. 17*. fissure for the, iii. 161. coronaria cordis minor, ii. 597. maxima cordis, ii. 596. innominata. right, iv. 815, 816. porta?, s. 325. 327. 381. stilcus of, iii. 161. prseparata, or frontal vein, i. 748. saivatella, iv. 1407. saphena, i. 15.148; ii. 238. major, iii. 128. minor, iii. 128. Vents comites, i. 360 ; iv. 1407, et sr?. accompanying arterial vessels of muscles, iii. 516. of bmchia'l artery, i. 217. innomir.ata? of Vieussens, ii. 597. magna? Galeni, iii. 631. 640. 705. minima?, or veins of Thebesius, ii. 597 ; iv. 1415. Venereal disease, suppurating node a symptom of, i. 449. VENOUS SYSTEM, iv. 1403. definition, iv. 1403. I. pulmonary veins, iv. 1403. II. systemic veins, iv. 1401. A. veins which form the vena cava superior, iv. 1404. 1. veins of the head and face, iv. 1404. facial vein, iv. 1404. temporal vein, iv. 1405. superficial, iv. 1405. middle, iv. 1405. internal maxillary, iv. 1405. occipital, iv. 140"'. 2. veins of the neck, iv. 1405. jugular vein, external, iv. 1405. anterior, iv. 1405. internal, iv. 1406. collateral branches, iv. 1406. vertebral vein, iv. 1406. spinal veins, iv. 1406. 3. veins of the upper extremity, iv. 1406. superficial, iv. 1406. radial, or external superficial veins, iv. 1406. ulnar, or internal superficial veins, iv. 1407. basilic vein, iv. 1407. median, iv, 1407. deep veins of the upper extremity, iv. 1407. satellite veins of the brachial artery, iv. 1407. subclavian vein, iv. 1407. brachio-cephalic veins (vena? innomi- nata?), iv. 1408. right vena innominata, iv. 1408. left venainnominatu, iv. 1408. collateral branches of biachio-ce- phalic, iv. 1408. inferior thyroid veins, iv. 1408. internal mammary veins, or vena? co- mites to the trunk oi each internal mammary artery, iv. 1408. vena cava superior, iv. 1408. azygos veins, iv. 1409. greater, iv. 1409. lesser, iv. 1409. left, superior, iv. 1409. bronchial veins, iv. 1409. sacral veins, middle and lateral, iv. 14(9. veins of the spine, iv. 1409. superficial, or extra-spinal veins, iv 1409, 1410. deep, or intra-spinal veins, iv. 1409, 1410. 13. veins which form the inferior vena cnva, iv. 1411. veins of the lower extremities, iv. 1411. superficial set, iv. 1411. saphena vein, internal or long, iv. 1411. external or posterior saphena, iv. 1411. deep veins, iv. 1411. deep plantar, external and internal, iv. 1411. poplita?al vein, iv. 1411. femoral vein, iv. 1412. external iliac, iv. 1412. internal circumflex ilii, iv. 1412. internal iliac, iv. 1412. common ili*c, right, iv. 1412. left, iv. 1412. collateral branches of common iliac, iv. 1412. ilio-lumbar vein, iv. 1412. middle sacral vein, iv. 1 H3. lateral sacral vein, iv. 1413. VENOUS SYSTEM — continued. inferior vena cava (vena cava as- cendens), iv. 1413. origin, course, and relations, iv. 1413. dilatations, iv. 1113. collateral branches, iv. 1413. renal veins, iv. 1413. supra-renal veins, iv. 1413. spermatic veins, iv. 1413. ovarian veins, iv. 1413. lumbar veins, iv. 1413. inferior phrenic veins, iv. 1413. portal venous system, iv. 1414. inferior mesenteric, iv, 1414. splenic, iv. 1411. superior mesenteric, iv. 1414. trunk of vena portae, iv. 1414. hepatic vein, 1414. C. cardiac veins, iv. 1414. great cardiac vein, iv. 1414. posterior cardiac vein, iv. 1415. Venter, !. 1. See ABDOMEN. magnus of Kuminantia, ii. 11. Ventral hernia, congenital, iv. 950. notch, s. (26. Ventricles of the brain, iii. G25. 704. choroid plexuses of the lateral, iii. 634. velum interpositum, iii. 635. 704. Ventricle, third, iii. 676. 704. third, choroid plexuses of, iii. 676. commissure of, anterior, iii. 676, 677. posterior, iii. 676. soft, or grey, iii. 677. floor of, anterior part of, iii. r>76. middle part of, iii. 676. posterior part of, iii. 67G. openings of, iii. fi/G, 677. fourth, iii. 678 693. 704. choroid plexus of the, iii. 691. fifth, iii. 674. 704. development, iii. 675. lateral, iii. 674. body of, iii. 674. cornu, anterior, iii. 674. descending, iii. 674. posterior, iii. 674. morbid states of the ventricles, iii. 720 E. dilatation, iii. 720 E. in children, — hydrocephalus internus, iii. 720 E. in adults, iii. 720 E. colour of the fluid contained in the ventricles, iii. 720 E. choroid plexus, deposit of lymph on, 720 F. earthy concretions in, iii. 720 F. vesicles in, formerly regarded as hydatids, iii. 720 F. of corpus callosum, iii. 674. of the heart (or pars cordis arteriosa), i. 638. capacity of the, i. 657, 65S. See HEART (normal anatomy), of the larynx, iii. 112. of septum lucidum, iii. 674. development, iii. 675. Ventriculus anterior, s. dexter, s. pulmonal's, ii. 580. See HEART (normal anatomy). bulbosus, or gizzard, of birds, functions of, ii. 11, 12. sinister, v. posterior, v. aorticus, ii. 582. See HEART (normal anatomy). succenturiatus, or duodenum. See Duodenum. Venus decussata, ovarian ova of, s. [10[>]. Verelillum, ova of, s. [127]. Vermecelii tnarini. ii. 401. Vermes suctorii. 'See ENTOZOA ; Sterelmintha. t«uia?fbrmes. See ENTOZOA ; Sterelmintha. teretes. See ENTOZOA ; Sterelmintha. vesiculares. See ENTOZOA ; Sterelminlha. unciati. See ENTOZOA ; Sterehnhitha. Vermiform animals, mode of progression of, iii. 434. appendix, development of, s. 402. process, inferior, iii. 678. 6*9. superior, iii. 678. 688. Verrucarite, organs of reproduction of, s. 229. Vertebra; generally. See SKELETON. articulations of, i. 250. 255. dorsal, iv. 1022. Ik amenta subflava of the, i. 251. fibro-cartilaginous lamina? of, i. 250. analogy between a vertebra and a cranium, i. 740. caries of, i. 451. of Mammalia, iii. 235. of Carnivora, i. 475. See CARNIVORA. of Marsupialia, iii. '276, of Monotremata, iii. 374. table of the number of, in Birds, i. 272. See AVES. of Fishes, iii. 958. of Amphibia, i. 93. Vertebral arteries, i. 367. 731 ; iii. 704 ; iv. 816. 819. origin, iv. 819. relations, iv. 820. GENERAL INDEX. 887 Vertebral, arteries — continued. branches, iv to the prsevertebral muscles, iv. 820. to spinal arteries, iv. ^1 . t<» cervicalis profunda, iv. 821 spinal arteries, iv. 821. posterior, iv. 821. anterior, iv. 821. varieties occasionally observable in the, iv. 822. column, orBce of, in the progression of man, iii. 4-=>6. power and resistance of each vertebra, iii. 457. vertebral column of man compared with that of the lower animals, iv. 1296. vertebral, or smaller, muscle of diaphragm, ii. 3. system of muscles, iii. 511. vein, iv. 815. S'22. 1406. 140**. J'cr/chrata. muscular system of, iii. 541. nervous system of, reviewed, iii. 614. J'crlct, or bregma, i. 725. See CRANU M. J'ci (i^o, cause of. i. 416 ; iii. 723 C. production of the sense of vertigo by turning round quickly on one's own axis, iii. 7-3 C. Veru montanum, iv. 148. 150, 151 ; iv. 1252. See Caput gallinaginis. 1'esica natatoria of fishes, i. 376. urinaria, i. 37'3. See BLADDER OF URINE. Vesical arteries, ii. 830. . fascia, i. 388. plexus of nerves, s. 430. veins, i. 387 ; iv. U12. Vesicle, germinal, of Purkinje, s. 70. [87]. [133]. Vesicles or follicles, Graafian. s. 56. [M]. [*9]. See OVUM. Jt'sf'co-prostatic plexus of veins, iii. 933 : iv. 1412. Vest co-uterine folds, iii. 943. Vesicula spermatica spuria, iv. 151. development of, iv. 153. VEsicn A PROSTATICA, iv. 151. 1252. 1415. definition, iv. 1415. development, iv. 153. I. ana'omy, iv. 1415. Man. iv. 1-115. Quadrumana, iv. 1416 1428. Volitantia, iv. 1417. Insectivora, iv. 1417. Feraj, iv. 1417. 1428. Pinnipedia, iv. 1418. Marsupia'.ia, iv. 1418. Rodentia, iv. 1418. Cavia cobaya, iv. 1418. Edentata, iv. 1419. Pachydermata, iv. 1419. Solidungula, iv. 141'J. Ruminantia, iv. 1419. Cetacea, iv. 1421. II. physiology, iv. 1422. III. morphology, iv. 1423. addendum, iv. 1434. VesiculcE s. cellulae ae'reae, s Malpighianse ; alveoli pulmo- num, Rossignol, s. v63. minute anatomy, s. 270. epithelium "of the air-passages and cells, s. 270. elastic tissue of the air-cells, s. 272. VE«irrL.¥: SEMINALES, ii. 422 ; iii. 922 ; iv. 1429. definition, iv. 1429. comparative anatomy, iv. 1430. function, iv. 1431. tenuity of the walls of, ii. 422. calculi in the, iv. 86. Vesicular polypi of the nose, iii. 740. J'esicule copulatrice, i. 376. Vet-pa crabro, or hornet, ii. 865. Vtspertilionidts. See CHEIROPTERA. J'fsp'-rtina. a section of the order I.epidoptera, ii. 867. characters of the section, ii. 867. Vespittce, or hornets and wasps, habits of, ii. 865. Veatibiilar artery, ii. 542. J'eslibule of ear, ii. 530. aqueduct of, ii. 533. fenestra of, ii. 544. fovea of, ii. 530. nerves of, ii. 530. openings into, ii. 530. development and abnormal conditions of the, ii. 557, MB. office of the, in the function of hearing, ii. 567. 577. Vestibule, the, atrium vaginae, iv. 1420; s. 710. bulbus vestibuli, s. 71.'. abnormal anatomy of the vestibule, s. 714. J't'stigium foramims ovalis, ii. 580. Vibratory movements of m? mbranous structures, theories of, iv. 1475. Vibrionirl(E, a family of Parasitic animals, ii. 113. organisation of the, ii. 113. Vibrionfdte, a family of Folygastric animals, iv. 4. characters of the family, iv. 4. Vidian artery i 4!'0 ; ii. 556 ; iii. 733. canal, i.~727 ; ii. 2*7, 283. nerve, i. 727. vein, i. 727. nerve, ii. 287. sulcus, i. 733. Vicussenian valve, iii. 678. 6S6. 690. nW of cervix uteri, s. 639. intestine, s. 350. epithelium of the villi, s. 351. basement membrane, s. 3ol. blood-vessels, s. 351. basis of the villus, s. 352. cyloblasts or nuclei, s. 352. lacteals of the villi, s. 352. muscular constituent of the villi, s. 353. changes in the villi during digest ion, s. 355. abnormal conditions of the, 6. 412. of the lacteals, i. 21. placental, s. 717. Vinegar, or acetic acid, considered as an article of food, s. 395. Vinegar-eel, or Anguillula aceti, ii. 113. Vinous liquors, nutritive properties of, ii. 14, 15. basis of all vinous liquors, ii. 14. Viper (Coluber verus), nervous system of the, iii. 620. poison-fangs of the, iv. 291. 888. its mode of attack, iii. 44H. Vis insita of Haller, doctrine of the, iii. 519. in connexion with the vis nervosa, iii. 30. medicatrix naturae, theory of, iii. 145. See LIFE. mortua, Haller's description of the, ii. 58. nervosa, iii. 29. 720 H. See NERVOUS SYSTEM, physio. logy of the. vis insita in connexion with vis nervosa, iii. 30. new laws of action of the vis nervosa, iii. 30. 1'iscache, anatomy of the, iv. 373, et seq. Vision, phenomena of, VISION, iii. 337; iv. 1436. Dr. Buckland on the early condition of the surface of the earth and condition of the atmosphere, iv. 1436. light, in reference to the phenomena of vision, iv. 1436. opinions of the ancients, iv. 1436. Newton, Huyghens, and Young, iv. 1436. velocity of luminous undulations, or rapidity with which light travels, iv. 1436, 1437. white light, composition and proportion of, accord- ing to Newton and Fraiinhofer, iv, 1437. colours of which the solar spectrum in reality consists, iv. 1437. calorific rays of Sir \V. Herschel, iv. 1437. chemical rays of Dr. \Vollaston, iv. 1437. influence of the chemical rays on the vegetable world, actinism, iv. 1437. diversified colours of flowers, birds, &c., due to the action of matter upon light, iv. 1437. complementary colours, iv. 1438. chemical, electric, and phosphorescent light, iv. 1438. transparency and opacity of bodies, iv. 1438. refraction, iv. 1438. focus, focal distance, or focal length, iv. 1438. aberration, spherical, iv. 1438. chromatic, iv. 1438. achromatic lenses, iv. 1438. phenomena of vision, iv. 1439. function of the retina, iv. 1439. dioptric phenomena, iv. 1440. vision under water, iv. 1441. distinct vision, iv. 1142. experiment of Father Scheiner, iv. 1443. optometer of Dr. Porterfieid, iv. 1443. greatest distance of human vision, iv. 1443. duration of impressions, iv. 1444. dimensions of objects, iv. 1445. apparent magnitude, iv. 1446. linear magnitude, iv. 1446. erect vision, iv. 1446. single vision, iv. 1447. adaptation to distance, iv. 1450. magnifying lens, iv. 1452. hypothesis of S'ngle vision, of Newton and WoU laston, iii. 771, 772. adaptation of the eye to distances, iii. 792. relation of the fifth pair of nerves to the sense of, ii. 309. abnormal vision, iv. 1452. achromatopsy, iv. 1452. relative frequency of the affection, iv. 1453. hereditary tendency, iv. 1453. influence of sex, iv". 1454. hypotheses, iv. 1454. congenital achromatopsy, iv. 1454. dichromatic Daltonism of Wartmann, ir. 1434. polychromatic Daltonism of Wartmann, iv. 1455. list of the most common confusions of colour, 1456. cases, iv. 1456, 1457. non-congenital achromatopsy, iv. 1457. permanent, iv. 1457. temporary, iv. 145s. causes of the affection, iv. 1460. remedial measures, iv. 1461. hypprchrpmatopsy, iv. 1461. anorthopia, iv. 1462. 888 GENERAL INDEX. VISION — continued. myopia, or near sight, iv."-1462. causes, iv. 14G3. course of the affection, iv. 1464. treatment, iv. 1464, 1465. presbyopia, iv. 1465.' causes, iv. 1465. remedial measures, iv. 1406. spectacles for myopic and presbyopic vision, iv. 1466,1467. cylindrical eye, iv. 1467. method of detecting the defect, iv. 1468, 1469. Professor Stokes's astigmatic lens, iv. 1468. treatment, iv. 1469. Vital action, dependence of, on oxygen, i. 257. retention of vitality in some organised substances, i. 257. laws of, iii. 142. See LIFE. affinities, iii. 151. See LIFE. capacity of thorax. See THORAX. contractility. See CONTRACTILITY. endowments of nerves and nervous centres, iii. 720 G. See NERVOUS SYSTEM, Physiology of the. phenomena. See LIFE. power of the organic world, i. 75, 76. VITAL STATISTICS, iv. 1469. methods for measuring the duration of human life, iv. 1470. mean age at death, iv. 1470. employed as a test of the sanitary condition of a nation, iv. 1470, 1471. employed as a measure of the relative sanitary condition of English counties, cities, towns, of town and country, and of the several dis- tricts of large cities, iv. 1471. used as a test of the sanitary condition of dif- ferent classes of persons inhabiting the same town or town district, iv. 1472. employed as a measure of the sanitary state of different classes of society, and of the mem- bers of different professions, without refer- ence to their place of icsidence, iv,, 1473. rate of mortality, iv. 1473. expectation of life, iv. 1474. mean duration of life, iv. 1474. probable duration of life, iv. 1474. Vitality, dormant, or inactive, iii. 141. 154. dormant vitality of seeds, eggs, &c., iii. 155. length of time during which the dormant vitality may be preserved, iii. 155. dormant vitality of seeds, iii. 155. of eggs, iii. 156. agents which destroy the vitality of seeds and eggs, and are calculated to produce important changes in their structure and composition, iii. 15''>. dormant vitality of plnnts and animals that have at- tained beyond the embryo condition, iii. 156. preservation of dormant vitality due to the maintenance of normal constitution, iii. 157. suspension of vital action under other circumstances, iii. 157. hibernation of plants, iii. 157. of animals, iii. 157. animals enclosed in rocks and trees, iii. 158. syncope, iii. 15S. suspension of vital action in parts of the human body, iii- 159. the " Atomic theory" of Dr. Daubeny quoted, iii. 159. Vitdline membrane, structure of, in various animals, s. [133]. [137]. chemical composition of, s. [141]. See OVUM. Vitelltcs, yelk, or yolk, s. 3. See OVUM. Vitreous humour of the eye, ii. 191. canal of Petit, ii. 19-2. chemical composition, ii. 192. corona ciliaris, ii. 193. Viverra nasua, organs of voice of the, iv. 14*9. Viverridee, or palm-cats, dentition of the, iv. 91 1. Viviparous animals, i. 146. generation, ii. 424. Voce di testa, or falsetto voice, iv. 1483. VOICE, iv. 1475. definition, iv. 1475. the voice in infancy, i. 70. pomum Adami", projection of the, i. 70. in old age, i. 79. modifications of the human voice, iv. 1475. organs of voice, iv. 1175. vibratory movements of the vocal organs, iv. 1475. 1476. experiments, 1477. vital state of the vocal ligaments, iv. 14KO. influence of variations in the hygrometrie and ther- mometric states of the air on the pitch of the voice, iv. 1481. alleged analogy between the action of the vocal li- gaments, and that of the reeds of musical instru- ments, iv. 1*81. the falsetto, or voce di testa, iv. 14^3. influence of the ep glottis on the voice, iv. 1485. VOICE — continued. art of singing, iv. 1485. musical varieties of the human voice, iv. 1485. action of the vocal organs in producing speech, iv. I486. effects of the lesion of the recurrent nerves in en- feebling the voice, iii. 895. reasons why persons born deaf are also dumb, iv. 1173. weakness of the voice, a sign of approaching death, i. 800. comparative anatomy, iv. I486. Mammalia, iv. 1486. Quadrumana, iv. 1487. Cheiroptera, iv. 1488. Insectivora, iv. 1489. Carnivora, iv. 1489. Marsupialia. iv. 1491. Rodentia, iv. 1491. Edentata, iv. 1492. Pachydermata, iv. 1492. Ruminantia, iv. 1494. Cetacea, iv. 1494. Birds, iv. 1495. epiglottis, iv. 1495. rima glottidis, iv. 1495. muscles, iv. 1496. larynx, superior and inferior, iv. 14%. bones of the inferior larynx, iv. 1496. membrana tympaniformis, iv. 1497. arytenoid cartilage, iv. 1497. trachea, iv. 1500. physiology of the voice of birds, iv. 1500. Reptilia, iv. 1501. Sauria, iv. 1502. Chelouia, iv. 1502. Batrachia, iv. 1502. Ophidia, iv. 1502. Insecta, iv. 1503. buzzing or humming of insects, iv. 1504. vocal muscles in comparative anatomy, iii. 544. Voles, water, anatomy of the, iv. 370, et seq. Volitantia, Weberian organ in, iv. 1417. Volition, the corpora striata the centre of, iii. 722 L, 723 E. Volvocinida;, a family of Polygastric animals, iv. 3. characters of the family, iv. 3. Volvox globator, iv. 6. mode of generation of, ii. 407. 432. Vomer, or ploughshare bone, i. 726 : ii. 213 ; iii. 725. borders, ii. 213. 1. superior, ii. 213. 2. anterior, ii. 213. 3. inferior, ii. 213. 4. posterior, ii. 213. connexions, ii. 213. development, ii. 213. structure, ii. 2J3. surfaces, ii. 213. 1. right, ii. 213. 2. left, ii. 213. Vomiting, act of, s. 316. causes, ii. 26 1; s. 316, 317. inverted action of the oesophagus in, iii. 760. Vortfcella convallaria, iv. 397. cyathina, iv. 7. niicrostoma, mode of reproduction of, s. 8. VorticellcE, their power of contraction, iii. 533. mode of generation of the, ii. 407. the vorticella an illustration of the relation which exists in the reproductive function between the animal and vegetable kingdoms, s. 256. Vorticellinidce (bell animalcules), a family of Polygastric animals, iv. 4. characters of the family, iv. 4. Vulva, the, s. 708. Fw/no-utenne canal, s. 706. See Vagina. rw/flo-vaginal glands, s. 712. W. Wad>'ng birds (Grallatores), characters of, i. 2C9. K'alkiiifr power of man, iii. 459. tables of the mea-ure of the inclination of the trunk in various modes of progression, iii. 460. estimate offerees employed in walking, iii. 4fil. principles upon which walking and running differ, iii. Walrus (Trichechus ro?marus), dentition of the, iv. 916. Warm-blooded animals, tempera' me of, as compared with rold-blooded animals. See HEAT, ANIMAL. Wart-hogs (Phacochcerus) of Africa, teeth of the, iv. 870. Warts on lingers, ii. 528. warty excrescences of the anus, i. 184. Wasps ( Vespida?). habits of ii. 865. their habitations, and mode in which, and materials of which, they are constructed, iii. 11. pneumatic apparatus of the feet of wasps, iii. 443. golden wasps (Chrysidiclae), ii. 8C6. habits of, ii. 8H6. Waste of the organism of animals, s. 382. 385. GENERAL INDEX. 889 in the composition of the blood, i. 410. removed from living bodies by the skin, iv. 456. pressure of water on fishes at various depths, iii. 413. resistance of water to animal progression, iii. 413. 431. importance of water as an alimentary constituent, s. 3^7. mode of aqueous action on the various organs, s. quantity of water contained in the various kinds of food ordinarily made use of, s. 388. sound transmitted bv, ii. 566. Water-beetles, ii. 860. characters of, ii. 860. Wa'er-brash, or pyrosis, causes of, iii. 760, Water-cells of the camel's stomach, s. 507. 536. H aler-rat (Arvicola ainphibins), iv. :<-'.<. hibernation of the, ii. 7>'>4. See HIBERNATION. Water-scorpion ( N'epa cinerea), ii. 8f 8. Wnler-snakes (Hydrophyli;, mode of progression of the, iii. 4H4. -spider, instinct guiding the formation of her singular habitation, iii. 9. Watery vapour exhaled from the lungs, ii 140. •iie ear. See CERUMEN; HEARING, ORUAN or. tribe (Mustelidze), dentition of the, iv. 913. Weeril, its ravages in granaries, ii. 862. .' of the human bodv at different ages, i. 74. Whales, i. 502, et seq. spouting apparatus, i. 580. brain of, iii. 696. absolute weight of the brain of the, iii. 664. chemical characters of whale oil, ii. 233. vocal organs and voice of whales, iv. 1494, 1495. CETACEA. Wkart >n's duct, iv. 424. of the ear-cockle or purples in, ii. 1 13. Mmalcules, generative organs of, ii. 410. c'ormant vitality of, iii. 157. Whirlicigs, societies of, iii. 16. Whistle-bone, or huckle-bone. See Coccyx. White of the eye (tunica albuginea), ii. 174. White matter'of the nerves, iii. 586. 646. 654. See NER- vurs CENTRES. White spots on the heart, ii. 644. in the coats of arteries, iv. 87. substance of nerves of Schwann, iii. 592 ; iv. 1 140. swelling of the elbow-joint, ii. 73. or chronic strumous arthritis of the knee, iii. 60. anatomical characters of the disease, iii. 62. first stage, iii. 60. 62. second stage, iii. 61,62. prognosis iii. 61. symptoms, iii. 60, 61. of the wrist, iv. 1524. . false, ii.528. Whytt's views of the physiology of the nervous system, iii. Willis, circle of, iii. 673. 705. lateral, or posterior communicating, branch of internal carotid artery of Willis, i. 492. Wilson's muscles, iii. 032. Wings of insects, ii. 419. 539. 924. articulations of the wings, ii. 926. file of the wings, ii. 928. neuration, or distribution of the tracheae in the wings, ii 926. origin and development of the wings, ii. 925. table showing the areae of the wings and the weight of the body in various species of insects, iii. 4-21. of birds, iii. 424. Winking, action of the eyelids in, iii. 79. Winslow, foramen of, i. 502. Winter egg, or hibernating ovum, s. [117]. [119]. [127], [12*]. See OVUM. Wire-worm, ii. 861. - of, in meadows and corn-fields, ii. 861. Wolf-fish, dental apparatus of the, iii. 978. n ho'lies iv. 982; s. 594. Womb. See UTERUS. Wombat, characters of the, iii. 267, et seq. Wombat, digestive organs of the, s. 304. pelvis of the, s. 160. Women, depravity of, among the ancients, ii. 686. Wool-mouse, hibernation of the, ii. 764. See HIBERNA- • note. Woodpeckers, mode of climbing and apparatus for prehen- .;. 451. W'irmiana ossa. See CRANIUM. Worms (Annelida), digestive organs of the, s. 297. earth-worms, organs and mode of progression of the, iii. 441. ova of, s. [117]. luminousness of the earth-worm, iii. 198. parasitic. See ENTOZOA. found in the liver, iii. 196. See LIVER — Entozoa. Wounds of arteries, cannon-shot and gun-shot, i. •>.',. of the cornea, ii. 177. of the diaphragm, ii. 6. W. ane, teeth of the, iii. 978. Hupp. Wrfsberg, nerves of, i. 360. cutaneous nerve of, iv. 756. \VnisT-JoiNT, iv. 1505. normal anatomy, iv. 1505. bones which constitute the wrist-joint, iv. 1505. radius, iv. 150-S. scaphoid, semilunar, and cuneiform bones of the carpus, iv. 1*06. Wrist-joint, triangular cartilage of, i. 249. mobility of the. i. 256. ligaments, iv. 1506. anterior radio-carpal, iv. 1506. posterior radio-carpal, iv. 1506. external lateral ligament of the wrist-joint, iv. 1507. internal lateral ligament, iv. 1507. synovia! membrane, iv. 1507. mechanical functions of the wrist-joint, iv. 1507. abnormal anatomy, iv. 1508. congenital dislocations, iv. 1508. cases, iv. 1508, 1509. accident, iv. 1513. dislocations of the wrist, and neighbouring radio-ulnar articulations, iv. 1513. of the bones of the forearm backwards, with displacement forwards of the carpus, iv. 1514. luxations of the lower extremity of the ulna, iv. 1514. of the lower extremity of the ulna at the wrist-joint, backwards, iv. 1515. forwards, iv. 1515. of the bones of the carpus, iv. 1516. fractures of the lower extremity of the radius, in the immediate vicinity of the wrist- joint, iv. 1516. symptoms, iv. 1517, diagnosis, iv. 1518. anatomical character of the fracture, iv. 1520. of the lower extremity of the ulna, iv. 1521. disjunction of the lower epiphysis of the radius, iv. 1521. cases, iv. 1521. disease, iv. 1523. acute arthritis of the radio-carpal and of the inter-carpal articulations, iv. 1523. chronic strumous arthritis of the wrist, or white swelling, iv. 1?24. anatomical characters of the disease, iv. 1525. chronic rheumatic arthritis of the wrist, iv. 1526. anatomical characters, iv. 1527. synovial tumours of the region of the wrist, iv. 1528. morbid condition of the synovial bursae of the flexor tendons, iv. 1528. painful crepitation of tendons around the wrist, iv. 1529. surgical anatomy of the wrist. See HAND. wrist-joint contrasted with ankle-joint, i. 154. X. Xanthic oxide (xanthin) calculus, iv. 80. Xanthoproteic acid, iv. 164. Xanthous races of man. See VARIETIES OF MANKIND. Xiphias gladius, i. 115. Xiphoid appendix, or ensiform cartilage, iv. 1023. ossification of the, iv. 1024. Y. Y-shaped cartilage of pelvis, s. 117. 120. Yapock, or fresh-water opossum, iii. 261. Yairning, probable causes of, iii. 722 K. sympathy in, iv. 852. influence of on paralytic limbs, iii. 40. Yeast-p\»nt, mode of reproduction of the, s. 224. Yelk. yolk, or vitellu*. of egg, s. 3. 68. See OVUM. yolk-mass, s. [86]. Youth, periods of, at which the animal heat differs from that of the adult age, ii. 663. Z. Zealanders, New, physical characters of the, iv. 1362. portrait of a New" Zealander, iv. 1362. causes of the tendency to extinction in the aborigines of. iv 1341. Zebra, the (Equus zebra), iv. 714. Zephronia. a genus of Myriapoda, iii. 546. et tfq. Zephnmiadte , a family of Myriapoda, iii. 546, et seq. characters of the family, iii. 546. 3 M 890 GENERAL INDEX. , a family of Polypifera, iv. 19. characters of the family, iv. 19, 20. genera of, iv. 20. Zoanlhus (Cuv.), Actinia sociata (Ellis), a genus of Poly- pifera, iv. 20. Zawj and •vj/t>%»j, meaning of the terms, as applied by the Greeks, iii. 143, note. Zona pellucida, or external tunic, of ovum of Mammalia, s. [83]. contents of ovum, or parts within the zona, s. [86]. Zonu/a membranacea lamina; spiralis, s. zona Valsalva?, ii. 534. Zoophytes, organs of circulation in, i. G53. list of Zoophytes possessing the property of luminous- ness, iii. 198. Zoosperms, or Spermatozoa, i!. 112. See ENTOZOA j Sper- matozoa. Zoophaga, tribe of, characters of, i. 563. Zoosporrs, reproduction by means of, s. 212. See REPRO- DUCTION, VEGETABLE. of the two kinds of zoospores, s. 223. Zostera marina, mode of origin and early development of the embryo in, s. 250. Ztfgnemacete. mode of reproduction of the, s. 219. Zygoma, i. 749. Zygotnatic fossa, i. 727. ganglions, ii. 228. process of temporal bone, i. 734. or superior border of the rami of the lower jaw, ii. 214. surface of superior maxillary bones, ii. 208. Zygomaticus major muscle, ii. 224. relations and action, ii. 224. minor, ii. 224. relations and actions, ii. 224. Z/ygowato-maxillary, or external, surface of palate bones, THE END. lounoic PRINTED BY SPOTTISWOODK AND CO. Mi\V-STKKET SQUARE. THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW AN INITIAL FINE OF 25 CENTS WILL BE ASSESSED FOR FAILURE TO RETURN THIS BOOK ON THE DATE DUE. THE PENALTY WILL INCREASE TO 5O CENTS ON THE FOURTH DAY AND TO $1.OO ON THE SEVENTH DAY OVERDUE. BIOLOGY LIBRARY SEP 7 1932 MAR 3 1 1962 ifecm AW o s 1391 LD 21-y;/t-U,';Jl2 U.C. BERKELEY LIBRARIES CD35331D02 37389, UNIVERSITY OF CALIFORNIA LIBRARY