Digitized by the Internet Archive in 2015 I https://archive.org/details/cyclopaediaofana5185todd •Dr. J. B. Sanderson 211 Ovum) J Kespiration, Organs of Dr. Thomas Williams 258 Page Stomach and In- testine Sympathetic Nerve ... Dr. Drummond 423 Tegiunentary Organs T. Huxley, Esq 473 Euminantia Dr.T.SpencerCobbold 606 Uterus and its Ap- ) , ( Dr. Arthur Farre ... 545 pondages J j Dr. Brinton 293 SUPPLE]\IENT OVUM. — In Animal Anatomy and Physi- ology, the Egg, the product of parental se.\nal generation, from which the young of animals are produced. The Functions of Re[)roduction, 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 o[)erations 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 develojiment 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 being, and which are usually described under the titles of Ovology, Embryology, and FcEtal Develoi)ment. 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, lias been derived our knowledge of the individual facts and of the general laws relating to the process of embryonic development. The arraniiement 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 desci'iption of the formative process in different animals as may present a sketch of the general nature of Swpp. this interesting process in the whole animal kingdom.* In pursuing this plan, the topics to be dis- cussei! may be arranged under the following heads ; viz. — 1st. 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. Srd. The changes which the ovum under- goes in the process of Fecundation, and (in so far as the ovnin 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 te.x- ture of the body in particular. Cth. Tile Functions of the Embryo or Foetus as compared with those of the adult. The wide-spread importance of embryolo- gical anatomy and [iliysiology 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 oftlieir 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 Ti'as originally intended to have treated in the same article of tlie 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 Vegetabi.e Ovum. 2 OVUM. the stnictui'e and function of an organ is only to be obtained by the observation of its foetal conditions, the stiuly of develo[)inent is acces- sory or supplementary to many departments of anatomy and physiology ; that, in recent times, no branch of imjuiry relating to organic nature has made more rapid [irogress, has presented a greater amount of new dis- coveries, or has infliienceil in a greater degree the views of scientific men on allied subjects, tlian the scicTice of embryology ; that it is coextensive witli, and illustrative of, the whole range of comparative anatomy; that no sy'stem, therefore, of zoological classi- fication can be regardeil as philosophical or complete which neglects the facts and princi- [)les of fetal development: finally, that some departments of pathological anatomy receive considerable illustration from our science, ami that more especially the scientific study and comprehension of tei'atology or congenital malformations is foumled 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 j)hilosophical ana- tomy and physiology.* Before ])roceeding 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 re[)i’o- duction in the lower animals has matle so much |)rogress during the last few years, that it becomes necessary to j)lace before the reader a sketch ot the aspect in which more modern researches enable the [)hysiologist to view the relation of the ovum to the sexual generative function, and to the other means by which imlividuals are multiplied, or species are reproduced in the whole animal kingdom. In the Article (tunkration, the commonly receivccl distinction was drawn between tbe sexual and the non-sexual modes of genera- tion ; and inuler the hittei’ form a variety of processes ot Gemmation and Division were alluded to as occasional or constant substi- * A variety of cimimstances have coutrilmted to cause delay in the ajuiearance 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 del.ay. He has only to s.ay, that in the contcmpl.atlon of the vastness and imperfectly known condition of the subject, ho has ever felt more disposed to engage in the investigation of some of its det.ails, than to appear before the public as a systematic writer in regard to it. The dehay m.ay 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 gener.al views of the suliject than miglit 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 proces.s. At the time of the publication of that article, tlie sexual organs had not been discovered in a considerable number of the lower animals : but since then, tlie assiduous and accurate researches of embryologists have gradually diminished tlie numher 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 tlie division of the animal king- dom recently established by Zoologists, as Protozoa, comprehending the Polygastric In- fusoria, Rhizo[)oda 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 re|)roduction of the species ; hut in several of them, as is especially well known among the Polypine tribes, a vast multiplication of individuals, sometimes living separately, hut more frequently associated in giOLips, or living in united colonies, takes [dace 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 |)lant b}' budding. itecent investigations have made it more and more apparent, that the non-sexual multi- plication of animals ought to be di.stingnished into several kinds, according to the difterent circumstances in which it may occur. In u few, as already remarked, it is entirely with- out known sex : in otliers, the non-sexual pro- cess of gemmation, or division, gives rise to new individuals, wliich are simply the repe- titions of tlie perfect or conqilete animals ; and in a tliird set, the non-sexual multiplication occurs more frequently in an incomplete con- dition of the animal, and often consists in the pi'odnction 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 con.stitutes the variety of the reproductive proce.ss recently distinguished by the name of Alternating Generation. Three forms, therefore, of non-sexual animal repi'oductioi^ 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 tlie invertehrated animals; 1st. In Protozoa, in which sexual organs have not yet been discovered. * Tlie first two of these divisions ma}^ be described as sinijile imicellul.ar microscopic animalcules, the third rather as a compound or congeries of micros- copic animalcules: the Porifer.a, or Sponges, are in- cluded in this division of Protozoa, becau.se the balance of evidence is decidedly in favour of their animal nature. OVUM. 2nd. In Animals known to be capable of sexual generation ; including two varieties, viz. a. Multiplication of similar individuals, either in a mature or immature condition. h. Multiplication of individuals, generally dissimilar from those producing tliem, anti 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, su[i- plementary to that contained in the Article Guneratiox, maybe 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 ovum is in this article entirely restricted to the product of sexual genera- tion. This body is formed in theovar}' of the female parent (or in the female organ of a hermaphrodite parent) by a gradual 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 embz-yo. 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 Fig. 1. Ovarian Ovum of a Mammifer. a, entire ; b, burst, showing the germ-cell, with yolk granules flowing out of the vitelline membrane ; c,the ovarian ovnnn at an early stage of its formation, consisting of the germ-cell surrounded by a few yolk granules. * The most important of these will be noticed in a later part of the article. 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 organic cell of microscojiic size, generally situated near the surface of the ripe ovarian ovum : this is embedded superficially in, 2nd, The Vitellus, Yelk, or Yolk, a mass of oleo-albu- minous matter, partly fluid, and partly cellular and gi'anular, 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 Viidline, or Y olk- 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 [larts, 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 sinijilest 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 {fig- 1, c.). To this cell the sub- stance of the volk is added in the progress of its formation, generall}' in a gradual manner, but in some animals more suddenly. Fig. 2. Spermatic Filaments (From B. ICagner and Leuchhardi). a, speimatozoa of the squirrel. b. spermatozoa of tlie dog, in the interior of the dev'eloping 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. 4 OVUM. and almost always exhibiting, when recently mixed with water, vivid vibratory or andnla- tory inoveTiients, but in a few animals present- ing other forms, and without motion. These s|)ennatic fdaments or particles are developed by a peculiar process in tlie interior of tlie cells (xpcnii-cells) secreted in the male organ or testis. AV'lien the ovarian ovum lias arrived at maturity, the germ cell disappears as such, and if fecundation shall have taken place, that vesicle is succeeded l>y another minute cell, witli which the oriiiin and development of the new animal are most intimately associated. This secondary organic cell of the fecundated ovum has therefore been called the Em/irj/o- cflJ. The first changes, preparatory to the commencement of the tlevelopment of an embryo, consi.st in the formation out of the embryo-cell and yolk substance of an organised cellular mass, or of a membranous covering of the whole or a part of the yolk: this is the germ-masu, Ji/aslodcrDi, or germinal membrane. Fig. 3. Fecundated Ouum nf a dSIammifer, with the Embryo Ceil and its dicisinn. a, ovam witli the first embryo-cell ; h, division of embryo-cell and cleavage of the yolk round it ; c, second division and cleavage ; d, farther division ; ami c, 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-celi by changes of the nature of cjtogenesis, accompanied wiih 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 cells, which are descended from the original embryo-cell. From this blastodermic mass or membrane, the embryo, or foetus, or new animal, and in the higher animals some accessory parts, which are temporarily united with the embryo 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 Fevelopinent, or Fmbrijo-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^ itseltj 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 info a com- plete sexual individual ; but by an intermediate non-sexLial process of production, one or more new individuals are formed out of the body of that first develojied, 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 follovving.— 1st. 'J'he 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 ]ieculiar 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. 3th. 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. Gth. The [U'oeess 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- bal)le that in all sexual animals the generative process consists in the process above described, or in some modification of it. I refi'ain 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 (lart of the article. Looking back on this general .statement of the com- mencement anil progress of the genetic process in animals, it will be seen that the nevv being may be consiilered as taking its immediate origin from the progeny of cells descended from tlie embryo-cell. That OVUM. 5 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 tlie 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 e.xist- ence the organic cellular structure, consisting of oleo-albuminous materials, formed by the female of an animal species, and cajiable, when acted on by the spermatic product of tlie 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 tlie 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 of Gene- EATION. The necessity of distinguishing several kinds of non-sexual reproduction according to its occurrence in animals entirely wdthout sex, or believed to be so, and in those wdiich may 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 grow'th, as in Hy dra and various Polypes : other forms consist in the development of new individuals from germs so isolated in iheir 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 Salpa; 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 Medtisoid 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 ami 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. Ow'en in his various writings, especi- ally^ in his Essay on Parthenogenesis, and Lectures on Generation, &c., in hledical 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-sexnal 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 consideralile degree future ge- neral views of the whole siiliject 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; and, indeed, mostinstances 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 bnd either sprouting from tlie 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 [ii'incipal 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 thev'^ are thrown off from the e.xternal surface of the parent body, or are formed and become loose within its interior. These gemniules have frequently attained to some degree of development by the time of their sejiaration, 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 Physiology. 1851. B 3 (i OVUM. rapidly througli fluids. From the first they exhibit a minutel}' celkdar and granular struc- ture : hut 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 envelo[ie ; hut, nevertheless, it may often be difficult to distinguish between them and true ova. The tcuileney to the multiplication of indi- viduals by non-sexual re|)roduction is greatest among those animals which are of the siiu[)lest organisation, ami more especially among those in which the cellular structure [ireilominates; not that it is confmed to them, nor that it occurs in all animals so constituteil, but that it is much more frequent and complete in the siiu[)lest animals of each class in vvhici) it has been observed ; as if it were more liable to occur in those species in which the ])i ocess of individual develo|)ment had proceeded to the least extent ol’ 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- ])licatiou and orilinary growth in these very siui[)le animals ; 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 I he Process of lie^jrodiiction in Pro- tozoa, or animals in which the sexual distinction has not tjet 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 scjiarated geinmules or germs. For an account of the first of these jn-ocesses, the I'cader is referred to the articles Poi.ygastria and PoKirEK.v. f Among the Poh’gastria multi])lication 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 |)olygastria has been f're- (piently observed to undergo division previous to the formation of the fissure, by which the division of the external wall is coni[)leted, — a fact which has led some physiologists, as Ehrenberg, M. Barry, ami Owen, to attribute to the nucleus au important influence in this process of cleavage ; the fir.st of these ob- servers having even conceived the nucleus to iict the [lart of a male or fecundating organ. * See Mr. Paget’s recent interesting lectures on this subject, pulilislied in Mcdic.al (iazette, 184',). I A considerable numVier of tlie ])olygastric infu- soria described by Ehrenberg in bis great work on tliat cla.ss, 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 multi[)lication is either of a fissi- parous or geinmiparous kind, as in Vorticella, Uvella, and Polythalamous Rhizopoda, 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, ap|icar 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, arc inouldetl into a s[)herical form, and, being pro- vided with cilia, move about in the water with great vivacity for a considerable period. These gemmules are throwm off in numbers propor- tional in some measure to the activity of the nutrition of the sponge, and therefore princi- [lally during the early |)art of summer. Towards the a[)proach 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 capsidar germs. f But it a|)pears 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.j * See an interesting paper by Dr. Carpenter on the Genus Kumniulina 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 g-eneral, 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. t See I.aurent’s elegant memoir, Recherches sur rilydre et I’Eponge d'eau douce. 1842. f Allusion is not made here to the production of granules by the dillluence of an infusorian animal- cule erroneously taken by Ehrenberg for the depo- sition of ova, but to a very different process. Du- jnrdin, wdio pointed out this error (Hist. Nat. des Infusoire.s, p. 101.), is of opinion that, besides the processes of lission and gemmation, we know nothing with certainty ofthe 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 lie discovered to take place in these animals (Prin. of Gen. and Comp. Physiol, p. 249, and p. 917.). Observations of a similar kind are re- 7 OVXTM. 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 j oiing 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 paramaecian polygastrian, the Loxodes Fig. 4. Formation and extrusion o f ova nr germs in Loxodes hursaria (from Cohn'). a, animalcule, containing two young ; h, contain- ing six; c, one of the embryos escaping; d, e, two ciliated embryos. bursaria, wkicli is usually multiplied like the rest, in the fissiparous motle, 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 fciTcdto under the head of ‘sporiferous reproduction,’ by Prof. Rymer Jones, in the article Polygastria. _ * Stein, Untersuch. ub. die Entwick. der Infuso- rien, Wiegmann’s Archiv., 1849, vol. 1. p. 134. in Actinophrys, Aciueta, and Chilodon uncinatus. Cohn, in Zeitsch. filr Wissensch. Zoologie, Xov. 1851, p. 237. each presenting two contractile vesicles like the parent. The escape of these bodies, by their passage through an iiperture temporarily formed in the wall of the infusorian, was carefully observed ; the exit of each embryo occupied about twenty minutes. Soon after their escape the}' exhibited active ciliary mo- tion, and moved about with all the appearance of embiyo-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, w'hich has been carefully observed by Stein. This change, in which the animal appears double for a time, had been previously no- ticed by Kdlliker and others, and had been interpreted by Kolliker as the conversion of a single animal into two, by a process analo- Fig. 5. GregarincE (from K'dlUker.) a, single; h, c, d, united ; e, f g, tlie formation of the iiavicella-like progeny ; A, three of these na- vicellae (from Stein). * These animals w'ere first accurately described by Leou Dufour in 1837 (Ann. des Sc. Xat. vol. vii. p. 10.). They have since been studied with great 15 4 OVUM. gous to transverse fission. Stein, on tlie other hand, has been convinced by a very at- tentive observation of the different stages of this process, tliat it is of an oj)posite character, and that, [)revious to tlie develojmient of the young [)rogeny, two of the Gregarinae have become fuseil, or united into one. As the two are about to unite, tliey gradually cbange tlieir form from that of elongated planaiia- like animalcidcs, to that nearly of hemispheres, closely pressed together ; then a complete fusion or union occurs, and the whole of the gramdes of both having become amalgamated in one sjiherc, the development of the internal jtrogeny takes place gradually from the mass. This progeny consists in a vast multitude of minute bodies, shaped like the Navicelloe (among the Diatomacem), but dilfereut from these bodies, and very probably constituting the reproductive germs or endiryos of (dre- garime. The ilevelopment of this Navi- cella-likc progeny into the Gregarina does not ap|)ear as yet to have been ti accd ; as in this animal, like many other parasites, the ])rogeny is retjuired to migrate during its de- velo[)ment from one stage to another, and the little bodies ai'e passed out of the alimentary canal of the insect before undei'going farther changes. The views and observations of Stein, how- ever, shoidd they be confirmed by others, wonld [U'ove the very remarkable fact, that the phenomenon of conjugation, or fusion of two unicellular individuals, hitherto supposed to be confined to some of the sim|der plants, as Ulostcrium, Spirogyra and Zygnema, See., may occur also in animals of a similar simjile 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 ot Kblliker on the conjugation or fusion of two individuals of Actinophrysf , a spherical infusorian animalcule analogous to the Ainceba or Rhizo[)oda, by its slowlv con- tractile, amorphous te.xture, and its long, ra- diating, contractile proce.«ses. Kblliker oli- served two individuals of this animalcule to apiiroach each other, adhere, and gradually to fuse into one, which soon assumed the same globular form, with the radiated couti-actile jirocesses, as each of the two that formed it, and differing only from them by the increase success by various observer,s, .as V. Sieliold (Beitrag. Z. Natiirgescli. 'Wirbellos. Tiiiere, 183D, p. 03.). Jlenle (iMiillcr’s Arcliiv, 1845, p. 309.), .and Stein in the same. 1848, p. 182. Kollikcr (Zeitscli. f. M'iss. Zool. 1848 and 1849), and as many as eighty dif- I'erent species of them have now been discovered. * Zeitsch. f. Wisseiisch. Zool. March, 1851, p. 02. t Op. oit. 1819, p. 207. In this very interesting memoir Kiillikcr has proved the animal nature of the Actinoplirys by his observations on its contrac- tility, and on the manner in which the particles of solid matters, vegetable and animal, are involved in its substance for the purpose of digestion, and their reimains .again rejected w'hcn 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 Kblliker’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 Actinoplirys, 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 ini[)robable 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 -}- 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 varjing 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 it.s 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 directl)'. 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 [)lace 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 Actinophr3's; 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 germin.ativus (the testis of Ehrenberg) ; and by gemmation fi’om 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 jirocess in the low'er forms of plants. f Zeitsch. fur Wis.sensch. Zool. Feb. 1852. J Ann. dcs Scien. IS'at. 4845 and 1848. 9 OVUM. ual proiluction ; the second as coming under the category of alternate generation; and the Vorticella embryo of tlie Acineta-form either repeats its geninial multiplication, or becomes encysted, and gives rise then b}' its nuclear division to embryonal proiluction. Other new forms of Infusoria are described by Stein under the names Spirochona gemmipara, Dendrocometes paradoxus, and Lageno- phrys vaginicola, ampulla, and nassa, in whicli 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 [>lace, 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 S[)ecies 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 jjublicatlon of the great work of Ehrenberg, most imi)ortaut 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 iiossihilUy of primary, direct, or non-parenial production of animals, or of so- called spontaneous and eqiuvocal 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 ivork of Alex. Braun, entitled Die Verjuugimg in dcr Natur, Dreiburg, ISl'J. 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 insufficient 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 h\pothesis 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 Inlusoria, 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 tlie 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. Ihe 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 infa.sion ; b, tube, with caustic potash ; c, tube, with sulphuric acid. * Eschricht, in Ediur. Isew’ Phil. Journ. vol. xxxi. 1841. p. 355. t P. 42'J. lu OVUM. servers* placet! in a glass flask an infnsion of organic matter, a jiortion of which was known from comparative trials, when left exposed to the o|)en air, soon to have animalcules deve- lo[)etl in it in great tjnantit}’, and he connected this vessel with a tubular a|)paratus, by two apertures, in such a manner that the air, which was made to pass fretjuently through the vessel containing the infusion, should be drawn through strong sulphuric acid, or [totash solu- tion, before reaching it ; and Schwann I ar- ranged a similar exiieriment, 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 ex[)eriments, the infusion and the a[)paratus were carefully sulijected to the tem])erature of boiling-water, by which it was presumed the vitality of all ova, or germs, or other or- ganic particles must have been destroyed : ami the result was the same in both the series of experiments, — viz., that, after a consider- able lapse of time, no animalcules nor con- i’ervoid plants were formed : but when the atmospheric air was aftervvanls allowed to pass freely over the same infusion, without lu'ing subjected to the processes before men- tioned, a rapid [iroduction of infusory ani- tualcules took place in the usual manner. The results of these experiments appear to be on the whole satisfactory, and nearly to deciilc 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 sur[)rise, when the very indestructible nature of some kinds of infusory animalcules is con- sitlered. It has long been known, and has been ascertained by the careful experiments of Spallanzani, Bauer, and Doyere, that some of the Rotifera and Tarriigrada are capable of supporting a high temperature without loss of life, anti of being kept for years even in the state of complete tlryncss, without loss of vitality: and, althoueh it must be ailmittetl that these animals differ greatly in their or- ganisation from the Polygastric Infusoria, and the latter aftpear to be very liable to destruc- tion from slight causes, yet it is possible that their germs may resist rlestruction in a greater degree than their adidt forms: and, should only one of these animalcules, or its germ, l>e left in anj' .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 [diysiologists are inclined to reject as fanciful ani.1 inaccurate the alleged observa- tions of the actual conversion of particles of organised or organic matter into living in- * roggeiwlorff’s Aim.alen, 1837, and Ediii. New I’hil. .Journ. vol. xxiii. p. t In paper on Fermentation, &c. in Poggen- dorlf’s Annaleu, 1837, p. 184. fusoria. At all events, statements of this kind are to be received with the greate.st 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 [larticles 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, w ere 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, somewdiat ana- logous to the fine moving [irocesses of the ciliated texture, than as distinct organisms, j- 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 same time be admitted that a more precise ac- quaintance with the nature of the germs from which these organisms take their origin is stdl required to render the arguments derived from this source entirely conclusive. J 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 aw'ay 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 w'ell 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 algte 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 winch they grow, or by their intro- duction into cavities opening on the exterior. All the internal parasites, orEntozoa strictly * Ami. d. Sc. Nat. March, 1845, p. 182. t See Article Sicjien. j Consult, especially, on the whole of this subject, Diijardiii’s Hist. Nat. des Infusoircs, 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 beings 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, wdiose 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 wdiole, 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 larva! 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 make their way from these situations into the alimentary canal, there to undergo their final development. Such appears to be the case with the Strongvlus armatus, living in an incomplete state in aneurismal sacs of the blood-v'essels 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 Lignia or Bothriocephalus solidus, in cysts of the ab- dominal cavity of fishes, and afterwartls 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 [ilaces 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 carrietl 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 'i To this question, also, recent observations seem to furnish a satisfactory answ'er ; 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 mav here refer to the original obsevvation.s of Schmitz, (Berlin, 1820), and the more recent ones of Valentin Gruby, Gluge, Vogt, and others. See Valentin, Kepertoriuni for 1842 and 1843. The Annual lleport in IMUller’s Archiv. for the same years, and in Vv'iegmann's Archiv. for Xaturgesch. Valentin’s account of the Ova of Distoma in the fluid covering the medulla oblongata of a foetal sheep (Muller’s Archiv. 1840, p. 317), and V. Siebold’s Article ‘Parasites’ in R. Wagner’s Handwbrterbiich der I’hysiologie. 12 OVUM. solitl substance of organs or tliroiigb mem- branes ; ami from the various stages of ad- vancement of others alrcatly referred to, seen in ditlerent parts of tlie same animal, little doubt can prevail that the}’ must have done the same : hut the a[)crture through which they make their way, besides being in most instances very minute, seems to close vi ry rapidly and com[)lctely after them. So that the occurrence of entozoa in entirely isolated cavities — such as the aqueous cham- ber of the eye, or in the |>arenchyina of solid organs, — does not now present to our minds any valiil olijection to the view that in all in- stances they are introduced from without ; and it will lie a[)()arent, from the same con- siderations, that even the occurrence ol en- tozoa in the iuutus, of which there are un- doubted instances, and to which great import- tnicc has been attaeheil as an argument in favour of their spontaneous origin, may be CNiilained 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 [loisons. The w hole history, then, of this remarkable class of animals, as it is now known, tends to su])[)ort 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, citlicr directly into the o|ten cavities, or more indirectly, by piercing the coats of vessels, membranes, c*tc., into the close cavities anil the iiarenchyimi of solid organs.’'' A candid review of the whole evidence on this (juestion leads to the inevitable conclusion, that, though all the difficulties or doubts which surround it are by no means conqilctely removed, the hy|)Othesis of [irimary 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 [n'c- viously existed. And if the present sonie- * As to the bearing of a knowledge of the liabits &c. of the Entozoa upon tlie question of their spon- taneous origin, consult the able essay by Eschridit ; “ Inquiries concerning the Origin of Intestinal Worms fxc.’’ in Edin. New Ehil. Journ. vol. xxxi. p. 314. 1841, the article on Parasites by V. Siebold, in It. ^\'agner's llandwiirt. der Physiol. ; E. Blanchard’s Pesearches on the Structure &c. of Intestinal IVorms, in Ann. d. Sc. Nat. 1848 and 1841), parti- cularly vol. vii. ]i. l'2l. Oujardin’s systematic work. Hist. Nat. des Helminthes, 1845. And in connec- tion with this and the whole subject of spontaneous generation, the S_vstematic Treatises on Physiology of Burdach, .J. Miillcr, Valentin, and Longet. what imperfect state of knowledge docs not permit us to affirm this absolutely, as the result of direct observation, the exceptions are .so few and unimportant, that they may he disregarded in the overwhelming evidence of a positive character in favour of the opinion, derived from analogy, that every organic being, if not |)roduced in actual union with another, derives its origin from a geim 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 adcled that the opinion which has attributed the pro- iluction of various animals to conversion or gradual transmutation out of other sjiecies 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 de[)arture 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 « non-scxiial ‘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 ])ennanent reproduc- tion consists in the development of the new being from the blastodermic mass formed by a [teculiar 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 Emhryological 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 ofa marked kind, afterwards reaches the specific or ty- jfical form : these changes are usually called JMetamorphoscs. 3rd. The [iroduct of deve- lopment from the ovum does not itself become a complete animal, but gives rise, by a peculiar mode of generation ofa 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 moreofwdiich ultimately attains to the specific resemblance of the sexual parents by which OVUM. the ova were prochicecl. This is the “ Alter- nating Generation” of Steenstrnp, 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- [dioses 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 term which has been used by Mr. Owen in his Lectures. Med. Times, vol. xx. 1849. 13 brated treatise under the title of “ Generations- Wechsel” in 1842.* ISo examples of this peculiar modification of the reproductive process have been knovvn 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 jirogeny 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 imperfectl}' 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 mav be a multitude of them; they may remain con- nected with the one producing them or they * A work w-hicli 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 liay- Society m 1845. OVUM. 1 !■ iiiiiy be detached and live independently, but they nevertheless constitute dili'erent animals, and cannot be regarded in any other light than as so many individuals distinct from the one producing them, although all arc dc- scemlcd from one ovum, or all are necessary to make uj) the entire s()ecies. And it is further to lie 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 iiulividual oluinge to new production that it may be difficult to determine to which of these forms of reproductive development their phenomena ought to be referreil. In that part of the article which treats sjiccially 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 liring prominently forward tliose instances of alternate generation which have been discovered since the publication of the Article (ticneration, or which, if previously know'll, 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. \Vc may first consider some cxam|)les of this process, or of one very analogous to it, in which the new animal is single. Echinudcrmala. — 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 ,1. Midler, 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 miglit almost be looketl upon as forming the connecting link between the tlirect and the alternating processes of repro- duction. In some of the Eehinodermata it ap|)ears 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 glarial'ts, Sars) leave the egg as a ciliated free moving animalcule, then they become pedieulated ami 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. Muller it ap- * Sars, Fauna Littor. Norvegia?, 1846; and Ann. ties Sciences Nat. ; Agassiz, Lectures on Comparative Embryology, New York, 1841); ami a Letter from Desor to J. Muller, in Arcliiv. fiir Fliysiol. 1849, p. 79. jiears that the mode of development now described is exceptional among the Echino- dermata, and that in other families of the ei der Astcriadffi, and in the Ophiura ami Echinidoc, an embryo or larva of a peculiar kind, is formed by direct development from the fe- cundated 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 developetl from each primary larva stock, and this gradually dies away, so soon as its attached offspring has made some mlvance in its formation. This hotly, described under the name of Bipinnaria asterigera, as con- nected with an Asterias, is a comparatively large animal, with a long pedieulated botly, 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 Echinoclerm 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. 15 testine, and anus, and moves activelv through the water. Sars who had observed this body in 1835, was the first to suggest in 184-1 that it might be the early condition of a star-fish’', and this view was confirmed by the admirable researches ofJ. Mliller-j-, and by observations of Keren and Danielson ij;. 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 Miiller'). A, Pluteus before the commencement of the fomiation of the Ophiura. B, Ophiura formed on the side of the gullet. * Wiegraaun’s Archiv. 1814, part i. p. 176. t Mem. of tlie Berlin Aead. 1846 and 1848. j Ann. des Sc. Kat. 1847, p. 348. and then appears to die without giving rise to any farther progeny. The gemmiparous larva of some other kinds of the Echinoderinata 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 1816 he traced the relation between one kind of this body which he had called Pluteus paradoxus, and the Ophiura, ami 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 activitv 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 Muller, and the process of gemmation has been traced by which the new Echinoderm takes its rise w’ithin 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 somef 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 iMuiler do not appear to give support to such a view ; and would rather appear to show (as in Auricularia, Jig. 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 larvm and metamorphoses of the Echino- dermata J, J. Miiller has pointed out that the Holothuridte 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. Miiller, in Mem. of Berlin Acad. 1846 and 1848 ; Derbes, in Ann. des Sc. Kat. 1847. t As Carpenter, loc. cit. p. 639. j Memoirs of the Acad, of Scien. of Berlin, Xov. 1849, and Apiil 1850, published in 1851, p. 35. IG OVUM. own re.searclies ami tlic comparison of some others, to bring tlic whole of the Echino- dcrinata under a general view, the result of which is the determination of the three fol- Fig. 9. Auficularia, or lari'a of Eehinoderm {from Mlillrr'). A, young larva of Aurieularia. h, atimontary canal ; a, Echiiioclerm beginning to be formed. IS, larger larva of the same Idud, a Echinoderm farther advanced. lowing varieties of metamor[)hoses and pro- dnetion among them. In all of them the embryo, immediately developed from the ovum, has a bilateral .symmetrical form, and jsasses by the subse(|uent 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 periotl, when the embryo has a general covering of cilia, blit not the special ciliated borders or limbs of the Pluteu.s. 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 Asteriadie, as in Eehinaster, Asteraean- 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. Ihe Echinotlerm is [ilaced upon the Plnteus somewhat in the manner of a picture on an easel, or a piece of emhroideiy in its frame and stand, and incorporates a part of the digestive cavity with itself. The remains of the larva gradually disappear, as in Ophiiira 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 Comatida passes very rapidly' through the stage of the bilateral form into that which Miiller has called ]iupa 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. Rliiller has remarked that these [iheno- mena partake in part of the nature of meta- inor[)hosis, and in part of that of the non-sexual gemmation 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, [iroducing 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- sexual gemmation is multiple. Poh/pinct. — The animals usually compre- hended in the general denomination of Polypes 01’ 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 rese.'U'olies of J. Mtiller on this subject have been published in a separate form, as well as in the Mem. of the Berlin Acad. These IMemoir.s, and others ou the same subject, will be fouml also in Muller’s Archiv. 1840, p. 108 ; 1847, p. 160; 1848, p. 113; 1849, pp. 79. 84. 364. 400 ; and 1830, 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 Ciliobrachiate Polypes, which, though pre- senting a considerable resemblance to the Polypes in their external anthoid appearance, yet approach much more nearly to the Tu- nicated 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 ami branches, or on a more solid stock. But the common fresh water Polype, or Hydra, and the various Actiniae 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. Hydra viridis in different stages of extension and contraction, reproducing gemmipa/'ously, attached to the roots of duck-weed. fFrom Roesel.) 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 Stijop. 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. A, Hydra of autumn, bearing an ovum, o,and two spermatic capsules, s, s. n, spermatic capsule burst artificially, sliorving spermatozoa. c (from Laurent), ova with J'oung Hynlra in various stages of development hanging out of them. n, 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 bodj-. c OVUM. 18 for that of gemmation which takes place tliroiigliout the whole of the summer.* The ova of Hydra are simple vesicular cap- sules of a brownish colour formetl in the sub- stance of the wall of the animal’s body, and separated from it previous to tbe ilevciopment of the young ; while the s|)ermatic filaments are formeil in smaller conical ca[)sules placed nearer to the base of the tentacula either in the same or in dificrent individuals. f The for- mation of the young I’olype has been observetl by Laurent J to take [)laee 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 {scefi^. 1 1. c.). The origin of the ovum in this animal is shown to be quite dif- ferent from that of a Inul : the former having the shape of a distinct vesicle from an early [leriod, the latter not being |ierceptibly 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 (^sce Jig. 1 1. i),dL). The Hydra, therefore, while [iropagatiug very frciiuently by gemmation, is capable of I'eprotluetion also by fecundated ova, whicii are directly develo[)ed into the [)arental form. Eut many of the true Compound Polypes pre- sent examples, in their niulti|)lication by gem- mation, of the production of intermediate forms of animals between the ova and the jierfect sexual individual, — a mode of repro- duction, therefore, which may be referred to Steenstru[)’s general law of Alternate Gene- rations. Thus, to begin with the simplest form of these animals liearing 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 Poly[)es ; 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, acipiire some of them male and others female sexual organs, and produce fecundated ova. * This effect of the cold season in changing tlie mode of production from gemmation to oviparous formation, thus checking growth, but providing for the preservation of tlie species tlirough the winter, is, as remarked by Dr. Carpenter, an in tei-esting ana- logy w'ith tlie cliange that is known to occur in the mode of production of the Aphis insect ; see Prin- ciples of Physiology. t Tlie co-existence of ovigerous and .spermigerous capsules on the liody of tlie Hydra has been observed by many, as, first by B. de Jussieu, in 1743; (Ab- hand. der Swed. Acad. 1746, vol. viii. p. 211): bv Trombley, in 1744 (MJm. sur les Polypes d’Eau douce); by Rbsel (Insecten-Belustigung) ; Palla.s, in 1776 (Karakteristik der Thier-pflanzen, p. 53) ; and more recently by Ehrenberg, in 1836 and 1838 (Verhand. der Naturfiirsch. Freundej in Berlin, 1838, p. 14); V.Siebold (Lehrbuch der Vergleich. Anat.); and by myself (Edin. Neiv Phil. Jourii. 1847). X Xouv. 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. Syncori/ne, developivrj a 3/cdusnid progeny. Oceania (^From LXsor.) A, natural size. n, a portion enlarged, showing the budding of Medvxsoids in different stages. o, one of the IMedusoids, naturally detached. I), another, farther advanced; of, ovary, or tes- ticle, placed on the alimentary carnal ; o', ova. R. Wagner appears to have been the first to observe Medusoid bodies produced from the Polype animals, as in Coryne aculeata, in 1833+, but the more full observation of the remarkable phenomenon of their formation is due to the researches of Sars, Lowen, Steen- strup, and Van Beneden, who have ascertained the relations of the Polype larva and Medusoid progeny, and the production of ova from tlie 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, observetl the formation of their ova, and the subsequent development of these ova into Polypes. * See fig. of Sjmeoryna Sarsii, from Sars, Fauna Litt. Norveg. 1846; and Steenstrup’s figures of Coryne fritillaria, tab. 1. fig.s. 41.43, and Desor, in Ann. des Sc. Xat. 1840, pi. 2. figs. 13. to 16. t Isis for 1833, p. 256. Also in Coryne vulgaris, in leones Zootom. Tab. xxi. 1841. J Annal. des Sc. Nat. 1845. OVUM. 19 In a certain number of the Campanularla, Sertnlariffi, and Tubularite, of which the in- ternal structure is more complex than in the Corvne, and in wliich the Polype always na- turally pi'esents 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. Franch of Sertularia gerdculata, magnified, shewing polypes, and ovigenous 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 Pol3 pe 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 tbrm ova which are de- veloped into the Polype form.* * See the View of Campanularia geiiiculata, by Van Beneden, in Mem. de I’Acad. de Bruxelles, 1844, vol. xvii. ; and Ann. des Sc. Nat. tom. 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 f, would show that in the Campanularia Fig. II, Campanularia. ( From Fesor.') A, po rtion of a branched stem, magnified, c, nou-sexual head or individual ; gg, two capsules, or modified heads, producing Medusoids by gemma- tion, in difterent stages ; m, Medusoid escaping ; m' m", Sledusoids more advanced, moring 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 embiwoes, w hich, when excluded, move for a time, and then, like the others arising from the detached Medusce, 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 IMedusoid progeny not being developed, and the ova giving rise to forms similar to the parent P0I3 pe : 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. j Ann. des Sc. Nat. 1849, xii. p. 208. § Muller’s Archiv, 1850, p. 53. 20 OVUM. A, modified or bell-shaped polvpe head or cap- sule, producing the female individuals at \ the earliest of these budding from the granular stem g'. n, the female heads expanded from the bell ; one of them containing two ova, on; the other con- taining two ciliated cmbryoes, of which one is issu- ing at the summit of the attached medusoid, e e. ■ Snhiiltze), male heads of the same spe- cies ot Campaiiularia ; p, upper part of the polype head, or bell-shaped capsule; c, sexual capsule, or modified attached Medusoid, containing speniiato- zoa ; o', another ot the same, burst, and spermatozoa discharged, s ; c", other spermatic capsules advanc- ing behind the first. ledge of Desor’s observations, and has farther proved the necessity of fecundation for the development of the ova so produced in the Campaiiularia geniculata {see fig. 15. C.). The various modes of production as they have been observeil in the Tubularia by Van Beneden *, have been so fully detailed in the Article Poi,vpiFERA,that the reader is referred to that article for an account of them. But it is to be observed that the reconversion of the Medusoid progeny of this animal into the Polype form described by that author (see Article Poi,YPiFEnA,^g. 50., p. 45.), has not received confirmation from the re.searches of other naturalists. Much remains still to be learned of this remarkable process ; but enough has been ascertained to show that in a certain number of animals, usually known as passing the greater part of their lives in the Compound Polype condition, the state of sexual com- [fieleness frequently belongs not to the Polype, Imt to a progeny having the form of a Medusa, and produced by a non-sexual process of de- velopment from the Polype stem. Acuh-'pha:. — Some time before the peculiar history of the development of the Polypina, now sketched, was discovered, an equally curious and unexpected phasis in the genera- tion of some Acalephse or Meduste had been established by the concurrent researches of several inquirers ; by which it was shown that the animals familiarly known as sea nettles existed for a time in the early stages of their development in the form of an attached poly- poiil, and were produced by a process analo- gous to gemmation, or transverse fission, in numbers from this Polype stock. -f Adult Meilusae are perfect animals in which the male and female sexual organs are placed on distinct individuals. The fecundated ova which they produce are first developed into a ciliated moving animalcule somewhat like a polygastric infusorian. This creature, after * ]\Uin. de I’Acad. de Bruxelles, tom. xvii. f The Swedi.sh naturalist Sars appears to have taken the lead in this discovery, as early as 1828, by his observation of the Compound Polypoid, from which the Sledusa? arc thrown olf ; and subsequently, in 1835, by the discovery that this animal, or stro- bila, is really the young condition of a Medusa, or rather a colony of Medusae. Very interesting obser- vations of a similar kind were published by Dalzell on thisbodj', under the name ofHydratuba, in 1836, but his observations probabh' date from an earlier period (Edin. New Pliil. Journ. vol. xxi. 1836). Sars pursued the investigation of the proce.ss further, and published the results in Wiegmann’s Archiv, 1837 ; but the complete account of his observations was not published in the same .Journal till 1841 ; see also Ann. des Sc. Nat. foiT841. In the meantime V. Siebold had arrived at precisely similar conclu.sions, and sirbsequently their views have been fully con- firmed by Dalyell (Ilemarkable Animals of Scot- land) ; J. Peid (Ann. of Nat. Hist. 1848, and Phy- siolog. Pesearches) ; Steenstrup (Alternations of Generation) ; and Hrtxley (Phil. Trans. 1849, part ii.) See also Dujardin, Me'm. sur le Developpement des Me'duses et des Polypes Hydraires, Ann. des Sc. Nat. 1815. The reader is also referred to Dana’s great work on Zoophytes in the United States Explor- ing Expedition. Philad. 1848. OVUM. 2 1 undergoing a slight change of form, fixes itself by the narrowest end, and acquires tentacles like a Polype at the other, amounting for some time to eight. In this condition it appears to Fig. 16. Development of 3Iedusa:. ( From Sars, Steenstrup, and Daly ell.) a, b, ciliated free mcnung embryo fi'om the o^nim ; c, embryo attached by its pedicle ; d, its tentacnla beginning to be formed ; e, with four, f with eight tentacula ; g, the fully developed polype, producing other pclj-pes by gemmation ; /i, i, A, transverse di- vision and development of Medusa? fi'om the polype stock or strobila ; I, a pile consisting of four Me- dusoids just about to separate; m. n, and lower lateral view of Medusae separated from the polype stock ; 0, more advanced, natural size : p, r, (from Dalyell), p, 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 pol3pe state and budding at the side. 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 Medusa?, 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 Medusm 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 Strobilm 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 Medusa (Aurelia aurita) from Po- lype stock. (From Desor.) A, Meclusa-fonn larva? on tlie stock above the poly'pe, which remains at the base, a. B, lower suiface of a detached Medusa. c, D, natural size. Young Medusa? forming from the polvpe above its disc. c 3 22 OVUM. ami may remain for a long time in that state ; continuing to multijjly by bnclding into others of the same kimi, ami occasionally giving rise by the process of fission to its Medusa [irogeny. The observations of J. lleiil* have shown that the Polype or polypoid stock may remain for a very long time in this condition without forming any ^ledusa progeny ; and these obser- vations, as well as those of Steenstmp and of di)esor, a[)|)car to show that these Polypes bear a considerable resemblance in their internal structure to the Medusic 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 Polv()c, 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 Poh pe remaining with its tentacles at the base of the Strobila of Medusio. The observations of Dalzcll and Fig. 18. Medusa larva. ( From J. Reid.) A, Polype before it has undergone any gemma- tion of Medusie, showing the month and'four canal openings. I!, file strobila or larva forming Medus.'e. c, lower surf.icc of one of the young Medusie, 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 iSledusa progeny, so that in one set the tentacles of the Polype may be included in the upper IMedusa, and when all the progeny is separated, new tentacles may be formed on the Pol_\pe stock at the base, while in others the budding Medusa may be within the circle of the tentacula of the Polyfie. It appears from recent investigations that • Ann. and Mag. of Mat. Hist. 1848. others of the Acalephte also undergo remark- able [irocesses 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 compouinl stock. f These are probably a progeny developed by budding from a single individual, which is the parent stem. I3y 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 Acale[)h 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 kiml 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 exam|)le of multiple metage- nesis, or alternating generation.;}; Mollusca. — Among the Mollusca the only examples of alternate generation that are yet known have been observed in the Tunicated Ace|diala : and among these, three modifica- tions of the reproductive process are known in the Bryozoa, Ascidia, and Salpidte. The Bryozoa, or so-called Ciliobrachiate Pol\pes, long i-anked 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 coni|)leteness, and the male and female organs are united in each individual ; the ova are fecundated within the cavity of the mantle; * Phil. Tran.s. 1840, Pt. ii. f Professor Goodsir has informed me that his ol)- sorvations on Stephaiiomaia are quite confirmatory of this view'. J See also on this subject the intei'esting treatise by Prof. li. Forbes, on the Naked-eyed Medusas, in Kay 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, tlieii becomes fixed, un. dergoes farther changes in being developed, Fig. 19. A series illustrating the development hy ova of Pedi- cellaria. (^After Van Beneden.') and now from its own body in some, and in otliers only from tlie spreading part of the stem or base which supports it, proceeds tlie gemmation of other individuals of the colony, all of which apparently are capable of sexual generation when they arrive at maturity. J 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 hke by generation. The soli- tary ones rarely multiply by gemmation, and when they 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 coni- pletene.ss, ami propagate by means of ova, in the same manner as the solitary or distinct Ascidiffi 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. -|- Although the changes to which both the Bryozoa and Ascidian Tunicata are subject in * Van Beneden, in IMem. de Bruxelles, tom. 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 phenow .na, and the special Memoirs of Mihie-Edwai-ds, s r les Ascidies Composces, &c., Baris, 1832; Liiwig and Kolliker, in Ann. des Sc. Kat. April, 18-16; Van Beneden, sur les Ascidies Simples, Brussels, 1847. their early state present some verj' striking phenomena of metamorphosis, yet there is nothing in either which fully deserves the name of alternate generation, for all the individuals of wdiich 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 ol the Botryllidas 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, Boweihanhia densa. (^After Farre.') a, one of the animals fully expanded. b, a similar animal completely retracted. c, an immature animal. d, one of the gemmaj in its earliest state. SalpidcE. — The most marked example of alternating generation among the Tunicata is that which, since its first discovery by Chamisso, in 1819, 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 ofit in this place. These animals are known in two states, viz. solitaiy and ag- c 4 OVUM. 2-t gregateil ; tlielatterbeing 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 ot one chain are of a similar sex either male or female. Fig. 2]. Solitary and aggregated Salpce. ( From Sars.^ A, solitary Salpa, with chain of aggregated ones, g, budding from it. li, this chain magnified, shewing the successive sets in different stages. c, one of the more advanced aggregated Salpae from a cliain,_/', the place of a foetus formed by sex- ual generation. i>, foetus from another more advanced, magni- fied; /i, 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 SaljitE are produced from a solitary one by a jirocess of internal gemmation, or gradual deve- lopment from an internal stolon, or germ-stock, Irom which they are detached gradually and in successive groups : all the individuals of tlie chain are contained within a tube, and become united to each other after their development, |)resenting a series of groups of different de- grees of advancement ; but the individuals in each grouj) being nearly at the same stage of development. The distinct or single Salpoe, 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 [iroceeds to its termination within the parent body, and theyoung Salpa is already jirovided with the internal stolon for the gem- mation of its chain progeny, before it passes into its separate state of existence. The solitary Salpa; may be looked upon, therefore, probably as incomplete or larva forms, and the aggregated are the fully deve- loped sexual individuals. The generation of tins animal, thei efore, 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 iiulividuals 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 develo|)ing 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 Eolitlae, deserves to be recorded, as it may be found to constitute an approach to the metagenetic process. After having de- scribed the usual [>rocess 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 i.s 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.” Fntozoa. — .Among the Entozoatheprocessof rcqiroduction is effected by very various means. All the Nematoidea, or round worms, are of distinct sexes ; and their fecumlated ova are developed into the parental form without any metamorphosis of a marked kind, (ex- cejjting perhaps in the Echinorrh) nchi, the * See Savigny, Mem. siir les Aiiim. sans Vertfeb. 1810 ; Cliamisso, De Salpis, 1819 ; Mej^en, Ueber die Salpen ; Esc-briclit, 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. I 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 life, 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 generation, 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 lorms of these animals, which w'cre 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 Wiegmaun’s Arcbiv, 1838. t Dr. Henry Nelson and I have observed tlie de- velopment of the ova in Ascaris inystax to proceed for several days, while the parent bodies containing them were immersed in oil of turpentine. X 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, 18-15, 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 Siehold, 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 1815, “ Here the doubt arises whether the asexual Cystica really deserve to be considered as independent animals. It is veiy probable that the ve.^icular 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. Jul)', 1850, translated in the Ann. des Scien. Nat. vol. xv. 1851, p. 177 ; and in the article Parasites, in AVagner’s Handwor- terbuch der Physiologic. E. Blanchard in his Rech. 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 searchingfor ova where noneexistedor 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 ace|)halocysts, 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 rOrganis. 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 Cestoidea, and atfirms 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 lib. 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 lirussels, in 1850, which I have not seen. * Med. Chir. Trans, of Bond. 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. § See V. Siebold’s Report on Zoology, in Ray Society’s publications, for 1845 and 1847 ; also Bui-- dach’s Physiol. B. ii. 2G OVUM. called by II. D. Goodsir ; and tliey have been observeil, in some instances, attached in pedi- cnlated vesicles, singly oringroups, to tlieinner Fig. 22. ICclntiococcus hnminis. {From inisoii.') A anil li, grouped and .single Echinococci, at- tached by peduncles to the inner luembrane of the cy.st. 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, tlie 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 lintozoa. They are afterwards set free, and in this state are found lloatingas minute wliitish particles in the tluid 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 |)art being furni.shed 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 tlie same kind ; but every thing that is known of the aceplialoc^ Stic productions seems to point to the view that they are all nearly allied, and that they are abnormal or aberrant conditions of Tmnia- larvae, which, when they become encysted, are inca[)able of development into the cestoid form which belongs to those tliat have reached the free intestinal habitation. The Caenurus, which has been met with principally in tire 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 II. 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. 184D ; and H. I). Goodsir, Anat. and Path. Obs. t See Curling, in Med. Chir. Trans, vol. xxiii. ; and Muller, in Jahrsbei'icht of Archiv, 1836. p. 106. cells, from which it is supposed other young animals or heads may be formed.* Fig. 23. Cimmrns cerebralis, magnified. {After Bremser.) a a, part of the general vesicle ; h, 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, ami 2nd, in its fasciolated condition, or in its transition, as it may beheld, to the cestoid, or tajic form. The vesicular Cysticercus has Fig. 24. Cysticerci. A, Cysticercus longicollis (from Bremser), en- lai'ged. 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 hir different from that of the Trenia itself. They are usually developed singly, that is each vesicle with one head : but some ob- serversf 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 Taenia in various states of development, from the vesicular condition of * II. D. Goodsir, loc. cit. t As Rose and II. D. Goodsir, loc. cit. OVUM. 27 the true Cysticercus, to a form in which the cjudal 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 UTouse, and Tcenia crassicoUis of the Cat. A, Cysticercus fasciolaris from the liver of the mouse, natural size, b, the head of the same, magnitied. (From Dujardiu.) c, head and first segments of the body of Ttenia crassicoUis of the cat, showing the double circle of hooks ; a few of the smaller under circle being seen where one or two of the lai'ger ones have fallen oif. A close comparison of the structure of the Cysticercus fasciolaris of the rat and mouse in its various stages of development with the Taenia crassicoUis 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.* * Dujardiu, Hist. Nat. des Helminthes, 184.5. E. Blanchard (who does not appear to have fully appre- ciated the necessity of change of habitation for the entire development "of the ta;nia), Sur rOrganisation des Yers, Ann. des Scien. Nat. 1848, tom. x. p. 848. V. Siebold, in Zeitsch. f. Wiss. Zool. 1850, and Ann. des Sciences Nat. 1851. I am indebted to Dr. Heniy Nelson, for an account of some interesting researches on this subject which formed a part of his Inauguiral Dissertation “ On the Development of the Entozoa,” on obtaining the degree of J\I. D. at the University of lidiuburgh, in 1860. 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 w'arranted, from the great similarity of structure, in adopting the view that the true vesicular Cysticerci, the Csenuri and Echino- cocci, are morbid or metamorphosed and aberrant conditions of the embryoes of various TmnicE, 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. Tteniae, Bothriocephali, and Tctrarhynchi ; 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 recentlj', has been involved in great obscurity, as it has been most variously ilescribed by different ob- servers both in tlie 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 oi'gans, 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 ha.s mentioned about sixtydifferent kinds of worms described by various authors under distinct ap- pellations, which might, according to him, be prevent me from entering into the detail.? 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 Tienia crassicoUis of the cat, enabled him to confirm, in a most satisfactory manner, the view which, unknown to Dr. Nelson, had pre^iously been taken by V. Siebold, that these cystic and cestoid forms are different stages of one and the same animal. See also Leuchart on Cysticerci, in Wieg- mann’s and Erichson’s Archiv for 1848. * See Gulliver, in Sled. Chir. Trans. 1841. 28 OVUM. bi'ouglit Milder the genus Tetrarhyncluis. In fact, tliis kind of animal undergoes sucli re- iiiarkahle changes in its transition from its first simjile Echinococcus-like encysted form to its free segmented sexual Taenia-like sha|ie, that it is not wonderful that its history should have been obscure, and that great doubts should still prevail with some Helminthologists as to its origin, development, and zoological relations.* It has alreatly been observed, that none of these three kinds of Cestoid Entozoa attain to sexual com|ileteness 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- (|iiire the male and female generative organs. The fecundated ova, producetl 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 tdong 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 arc thus made subject have hitherto opposed so great an obstacle to the observa- tion of their development, that we are as yet ill possession of very few continued series of observations in which the whole progress of ilevelopment i'rom the ovum to the complete segmented animal has been traced. Some im|iortant 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 tdready indicated paths of inquiry by which this very curious and intricate history may ere long be completely unravelled. The ac- oomjianying figures from Dujardiu’s work show the progress of formation of a small Tieuia inhabiting the Shrew, and give a suf- ficiently gooil idea of the nature of this pro- cess in a Ttenia, which consists of compara- tively few segments {Jig. 96. a to ?.). 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 empiricorum) in the encysted condition. Into this situation the minute TaeniiE 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 * "S on Siebold proposes to substitute the genus 1 etrarliynehus Ibr the following five genera distin- guished by Dujardin, viz., Ithynchobothrius, Antho- cephalus, 1 etrarliynehus, Gymnorhynchus, and Di- hothriorhynehus. 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 Taeniae 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 Taeniae reside. Fig. 26. Development of Taniia jAstiUum of the Shrew. (^F)'om Dujardinf) a, embryo within the ovum, just about to quit it, witii three pairs of hooks; b, embryo that has left the ovum, the hooks capable of rapid and exten- sive movements ; c, embryo moxdng freely (of the Tivnia serpeiitulum of the magpie) ; d, e, very young embryoes of Tamia ])istillnm ; /, g, h, i, different stages of growth of thisTicnia; the separation of the segments gradually increasing, and the develop- ment of the reproductive organs in the jiosterior ones; h (more magnified), the proglottis, or free moving separated segment of this T;enia. OVUiM. 29 The instance already referred to, of the iden- tity of the Cysticercus of the liver of the mouse and rat with the Taenia crassicollis of the cat, and a variety of detaclied observations which prove that the Bothriocephahis and Tetra- rhynchns 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. A, one of the longer mature posterior segments wuth the sexual organs fully developed ; o, o, rami- fied ovary full of ova ; o', the oviduct ; f, the tubu- lar testis ; f, 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 view ed in tf 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 Tetrarhynchus is formed : this, according to Blanchard, is its complete condition ; but, according to Van Beneden, the so-called Tetrarhynchus is con- verted into a Rhynchobothrius, and this is in the last place changed into a separate Tre- matode animal.* Dujarilin 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(seey?g. 26./r.)‘)'; but though there may be some points of analogy betw'een the single segments of Taenia anil a Trematode, yet the absence of head, diflerences in the alimentary canals, and other circumstances, render the correctness of this view, at all events, still doubtful, t Trematoda. — These animals, the most common of which are known as Flukes (ex- cluding the Planarite), 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 develo[)inent 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 I'Acad. Roy. de Belgique, 1849, Jfo. 1., and Anil, des Scien. Nat. vol. xi. 1849, p. 13. ; also a w'ork 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. tom xv. p. 309. t Hist. Nat. des Helminthes, 1845. j See also Leblond, in Ann. des Scien. Nat. 1 836, and Miescher, Bericht Naturforsch. Gesellsch. Basle, 1840 ; the Works of Riidolphi on Entozoa; the Article Extozoa in this Cyclopasdia, by Owen ; Kblliker’s Memoir on the Development of Inverte- brate Animals, in Muller’s Arcliiv, 1843 ; Eschricht on Bothriocephali, 1840, &e. &c. 30 OVUM. not itself converted by any direct process of (ievclo[)inent or metamorphosis into a perfect Distoina, but has gradually formed from germ- cells within it a [irogeny, sometifiies of one, more frequently a numher of botlies, which, when they arrive at maturity, [iresent each one an external form and internal structure ami locomotive powers, entitling them to be con- sidered as indc|)endent 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-cclls, a new progeny of animals ncai'ly 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 cj'cle ; but these are different from their immediate parents, and in their internal or- ganisation soon manifest the ty[>e 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 Sc7-ics of changes in the dcvehptnent and generations of Disfoma. (^From Steenstriip.') o. Ovum witli enibiyo or larva (levcloped in it. e, this embryo iu a free moving state ; ei, another embiyo in its interior. (These are of iMonostomum mutabile, from V. Siebold.) li, this last embryo farther advanced. 1, first stage, soon after it becomes free; 2 and 3, farther on, with g, the second generation, w'ithin them in various stages. G, 1, one of this second generation at an early jieriod of its advancement; 2 .and 3, farther on, with c, c, Cercariie or Distoma-larvce, within tliein ; g', one of the granular globules from -which the Distoma larva; and previous generations arise near the posterior part of the body. c, one of the Cercari;c or Distoina larva with its caudal appendage, r, 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 iu 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.* 'J'hc free Cercaria; are not, however, directly- converted into Distoniata; but appear always to undergo a previous metamorphosis in a chrysalis state, or enclosed in a pupa cyst. * Nitsch, Beitrag zur Infusorienkunde, &c., Halle, 1817; liojanus, in Isis, 1818; A remarkable and interesting series of papers by V. Baer, in Nov. Act. Nat. Curios. 182G, vol. xiii. ; Rud. Wagner, in Isis, 1834 ; V. Siebold, in liurdach’s I’bysiol. vol. ii. of German edit. p. 187., or vol. iii. of French transl., p. 32., &c. Previous to the formation of this cyst the Cercariae adhei-e 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 w'eeks, 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 wdiich this remarkable process of gene- ration has been ascertained to occur are due to V. Siebold and Steenstriip ; 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 atldition 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 1833 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 ditfering both from its immediate parent and from the adult.* V. Siebold, as W'ell as others, had ascertained the Cercarire 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 CercaritE on the one hand, in theirdevelopment 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 [treviously named Cer- caria echinata, C. armata, and C. ephemera. In these, especially in the first, the conversion of an encysted Cercaria by metamoi'phosis into a Distoma, and the descent of the Cercaria (by metagenesis) through two progenitors, not themselves Distomata, w'as 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 Steenstru[) 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, 1833. 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 Cercariae, after having previously been parasitic in the Mollusca. It is ea.sy 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 (larvce 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 oat 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.-t- Both these observers agree that the first and second germ-cases (or nurses), and the Cercariae, or Distoma-larvffi, arise by a process of gradual development from extremely minute granular spherides, wliich 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 larvte 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 whiih 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 Cants, 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 Physiologie. t See Fig. 28. g'. § Mikographische Beitrage, &c., 1832. 32 OVUM. ;it one time enc3’ste(l, and tliat of the two ])rinci[)al forms distinguished hy that observer, the one is the more advanced and the other is tlie larva. From what has already heen observed it seems probable that other [)rotlnctions pre- viously ilescribed as Entozoa of various kinds, may, in reality, be nurses or larva; of different Distomata; and that many of these may be brought under their several specific distinc- tions, when the new paths of investigation |)ointed out by the suggestions of Steenstmp and V. Siebold have been diligently pursued. Von Siebold has recently related* a very interesting observation on the remarkable double Trematode animal, discovered and described by Norihnannf , under the name of Diplozoon paradoxum, from which it seems to be ascertained that this double animal is produced by the actual union of two nearly similar sim|)le ones, by a process of partial fusion, which, though much less complete, seems to partake in some degree of the na- ture of conjugation, such as occurs in the Closterium and some of the lower vegetable boilies. The single animal, first described by ])ujardin, under the name of Difiorpa J, was observed infesting the minnow (Leuciscus |)hoxinus)in the same streams with the gudgeon ((fobio fluviatilis). This animal corresponds nearly in form and structure with the half of the Diplozoon, with the exce[)tion of its smaller size, and the absence of generative organs. On the side of the Diporpaa projecting sucker exists, and the union between two of these animals which gives rise to the Diplozoon, begins by a mere adhesion of this sucker, which becomes more and more complete, so as at last to lead to that entire fusion and combination of the adjacent parts of the in- testinal canal and some other organs, which has excited so much surprise in the Diplozoon. The develo[)inent of the genital organs in both of the two united animals succeeds to this union. Annelida. — Some phenomena in the repro- duction of the Annelida are to be referred to the imlircct mode of generation now under consideration. The most of these animals are hermaphrodite ; they are all more or less jointed, or forineil in the adult of repetitions of segments of similar structure, the ante- rior and posterior alone tliftering from the rest. The jointed structure does not exist in the embryo when it first leaves the egg ; but is gradually produced by a process of gemmation, which ma3' be styled intervening rather than fissiparous. In the multiplication of these segments the new ones are always formed in the interval between the caudcl segment and that which is next to it ; the seat of new production differs therefore in the Annelida and Cestoid worms ; for in the latter * Zeitschrift fiir Wissensch. Zook 1851. t Op. cit. j Hist. N.it. ties Helminthes, 1845. Dujardin had noticed the resemblance between this hod}' and the two parts of the Diplozoon, and had conjectured that it might be in some way the 3’oung of the Diplozoon. of these animals the new' joints are developed at the cephalic extremity, and there is also some difference in its nature, as the multipli- cation of joints in the Taenia is in some degree trtily fissiparous. A few of the jointed Annelida have long been knowm to be subject to another kind of development, by which one or more complete segmented individuals are foi nied close to their caudal extremity, and spontaneously separate to enjoy for a time an independent life. This remarkable fact was first described by Otto Fred. Midler, in the small Nais proboscidea* ; and Gruithuisen described accurately the same phenomenon in a Nereis or Chaetogaster.f This process was looked upon by these ob- servers as an instance of accidental fissiparous generation ; but it has received a different signification and a greater interest from the more recent researches of Quatrefages and Milne-Edwards. The first of these naturalists observed in a number of individuals belonging to the genus SyllisJ, at a certain period of their life, a new individual to be formed at the caudal extremity of each. The part was first marked off by a notch or transverse groove, the form of the parent individual gradually appeared in it, with the head, ey'es, the same joints, limbs, &c., and it was ultimately separated by spontane- ous fission. But the resemblance between the original individual and its offspring was chiefly external ; for it was found that while the parent animal continued to exercise as before the functions of nutrition it was not possessed of generative organs ; and, on the other hand, the new individuals seemed de- stined alone to perform the reproductive func- tions, and contained the fully formed sexual organs, while their alimentary canal appeared to become atrophied, and was not employed in the digestion of any newly assumed food. These individuals lived long enough after separation to complete the reproductive pro- cess by the formation of fecundated ova. Milne-Edwards observed in the Myrianida fasciata^, a similar, but more numerous gem- miparous production ofsexual individuals. In this animal, as many as six new individuals were observed to be formed in gradual succes- sion, one before the other, and between the caiulal and terminal segments of the original j body. Each one of these new individuals, as it * Natnrgesch. einigev Wurmarten des Siissen unci i Saltzigeii Wassers, Copenhagen, 1800 ; and in a j Nereis, in Zoologia Danica. i f Nov. Act. Nat. Cur. vol. xi. See also J. Mill- |: ler’s I’hy'siok, by Ifaly, vol. ii. p. 1424 ; Owen’s i Lect. on the Gener. and Develop, of the Inverte- ‘ brated Animals, in 1840, in Med. Times, vol. xx. jj p. 83, where he refers also to observations of Oersted j in an Eulosoma, and of Schmidt in a tubicolar An- ' nelide, called Eilograna. ) J Annal. des Scien. Nat. 1844, tom. i. p. 22. Otto i r. klUller had also noticed the phenomenon in the same animal, and described it under the name of i Nereis prolifera, in his Zoolog. Danica, vol. ii. p. 15. j § Annal. des Scien. Nat. 1845, tom. iii. p. 170. See also Longet’s Trade de Fhy'siologie, tom. ii. I part 3rd, p. 47. | OVUM. 33 arrived at maturity, and acquired the external configuration and structure (though of smaller size) of the parent, was found to be possessed of reproductive organs, while the original animal had not acquired any. The first Fig. 29. Myrianida fasciata. {From 3Iilne Edwards.) Twice the natural size. At the posterior part of the body are seen six young, produced between the caudal and the next joint in succession, from 1 to 6. I I I i i 1 I formed was situated farthest back, and re- mained for the time attached to the original caudal joint, and the others followed in suc- cession before it, the last produced being attached to the terminal joint of the parent body; and each newer individual presented a less developed structure than the preceding one. In the animal observed by M. Ed- wards, the anterior or youngest individual had only ten rings, the second had fourteen, the third sixteen, the fourth eighteen, the fifth twenty-three, and the last, or caudal one, thirty rings. It would appear, therefore, that the new individuals take their origin from the last joint of the parent Annelide. The observations of M. Edwards farther make it appear that the process of develop- ment and multiplication of the segments in each of the new individuals is the same as in the young Annelide first formed from the ovum ; that is, the embryo is at first without segments or rings, the head and caudal part existing alone, and the joints being gradually formed between them, and in succession, from the posterior of the segments previously pro- duced. These phenomena cannot fail to recal to our recollection the production of sexual individuals by a non-sexual process analogous to gemmation from imperfect parents or nur- Supp. sing stocks; and as Mr. Owen has remarked*, “ Since the individuals so propagated alone acquire the generative organs, an alternation of generations may here be affirmed of such species ; the oviparous individuals producing eggs from which the gemmiparous individuals come, and these, in their turn, reproducing the oviparous individuals.”-f- But it is to be observed, that in many others of the Annelida, the generation is of the ordinary kind, or consists in the produc- tion of sexual individuals, by their direct or metamorphic development from the ovum. Insecta. Aphides. — A remarkable example of a similar modification of the reproductive Fig 30. A. {After Owen.) Diagrammatic representation of the succession of generations of Aphides, from the fecundated ovxun o, the first embryo e, the suc- cessive non-sexual progenies, g to g (of each of which only one individual is represented), to the male and female insects, m and f. B. {After Ley dig.) Enlarged view' of the cham- bers of one of the ovarian oviducts of a viviparous Aphis. In the uppermost chambers are seen the fine nucleated cells, of which one in V and 2', larger than the rest, descends ; and in 3, 4, and 5, are seen the changes of this and other granular and cellular blastema, from which the new individual is formed. * Lectures, 1849, Med. Times, vol. xx. p. 83. t At the same time it ought to be mentioned in connection with the above, that, according to some D 31- OVTOI. process among animals higlier in tlie scale, hut in them of an exceptional character, has long heen known to occur in the various species of the commou plant-louse, or Aphis, first tlis- covcrecl hy Reaumur* and Bonnet f, and confirmed and more fully illustrated hy a variety of accurate entomologists in more recent times. In this animal, successive gener- ations, amounting each to a considerable num- ber, and in the Aphis lanigera J averaging about a hundred, are produced for seven, nine, or eleven times, according to the species, from parents of no sex, or rather which seem to possess the structure of females imjjer- fectly developed. The course of the gene- rative process is the following: perfect male and female winged insects are observed only towards the autumn season ; these fly about in great quantities, the impregnated females deposit their eggs covered with a protecting case of mucus in the axils and other recesses of plants, where they remain during the winter. In sjjring there are tleveloped from these ova a Irrood of larvEE, or imperfect female Aphides, which soon produce, hy an act of viviparous generation, and without any concurrence of the male sex, a[)rogeny of a similar kind, and this is repeated, in successive generations, for nine or ten times in the common species, or for ten or twelve weeks during the summer, at the end of which time the last brood brings forth male and perfect female individuals, both of which die after having provided hy the production of fecundated ova for the con- tinued generation during the next season. Upon the discovery of this very remarkable mode of reproduction, various theoretical con- jectures were made in regard to its nature ; hut no satisfactory explanation presented itself, till the knowledge of the general nature of the process of non-sexual larvation came to be brought under a general principle or law. It is now obvious that the production of the successive generations of Ajihis-larvai may be regarded as an instance of the multi- plication of individuals from the product of a single ovum, previous to the develo|)inent of the true sexual organs and the exercise of the sexual functions. But this example of non- sexual larvation deserves attention, not only from its occurrence among animals placed so high in the zoological scale of organisation as insects, but also from the degree of perfection of the larvae themselves, and from the circum- stance that the new broods are formed, not recent observations, the parent or stock individuals of both Syllis prolifera and Xais proboscidea arrive ultimately at sexual perfection after having given off a number of sexual individuals by the caudal gemmation. See Leuckart on Metamorphosis, Non- sexual Reproduction and Alternate Generations, in Zeitsch. fiir Wissensch. Zool. 18dl, in which he refers to Frey and Leuckart, in Beitrage zur Kennt- niss Wirbellos. Thiere, p. 96 ; and to Schultze, in Archiv. fiir Naturgesch, 1849, p. 287, for observa- tions proving this fact. * Histoire pes Insectes, Tom. iii. Paris, 1738. t Traitd dTnsectologie on Observations sur les Pucerons, 8vo, 174.5. 1 See Owen s Lect. on the Invertebrate Animals, p« 2i3o» as in the other examples of this process to which the attention of the reader has already been directed, b}' a division of the whole body, or by gemmation from its external or internal substance, but from germs aiising within a determinate organ, corresponding in its general form and anatomical relation, though not entirely similar, to the generative organ of the perfect female.* The genital organs of the viviparous or larval Aphides differ ?rom those of the perfect or oviparous females, principally in the want of the receptaculum seminis, and the organ which secretes the mucous investment for the ova, and there is also some difference in the form of the ovarium, or germiparous part of the organs.f The gradual development of the larva brood within the oviduct of the viviparous parent has been traced carefully by several observers. J. Victor Cams has attempted to show that this process is to be distinguished from the usual process of development from an ovum by the absence of cell multiplication, and by the formation of the embryo of the larva from a merely granular germ : but more recently Leydigt has shown that though there may be differences in the structure and mode of de- velopment of the ovum and of the viviparous germ, the latter arises as truly as the former from cellular elements. The uppermost com- partment of the oviduct contains, according to Leydig, from eight to twelve distinct nu- cleated cells, together with a quantity of finely granular substance. One of these cells appears to descend into the second compart- ment, in which an outer layer of cells exists, with finely granular substance internally : in the third compartment the cells of the outer layer have become still smaller and more numerous, and have formed, in fact, a covering to the germ, similar to that which proceeds from cleavage in the ovum. The rudiments of the internal organs now begin to be distinguishable, and the various external organs are successively developed out of the cellular mass. The cel- lular structure of the ovum of insects is at all times difficult to be traced in the earlier stages of development ; and it seems to be established by these observations that the origin of the embryonic structures from cells is at least as obvious in the viviparous as in the oviparous germ (see Jig. 30. b.). General Remarks on Alternate Generations. — Having now shortly described the principal varieties of the reproductive process which may be brought under Steenstrup’s law of “ Alternate Generation,” it may be proper to review very briefly their general nature. * It is conjectured by Von Siebold (Vergleich. Anat. der Wirbellos. Thiere, p. 634), that the same mode of production may occur also in some kinds of Cynips and Psyche. f See the interesting observations of Ow'en, in Parthenogenesis, p. 38., and elsewhere ; V. Siebold, Vergleich. Anat. and FT'oriep’s Neue Notizen, vol. xii. p. 308 ; and J. Victor Cams, Zur niihern Kenntniss des Generations-Wechsels, Leipzig, 1849. J V. Siebold and Kblliker’s Zeitsch. fiir Wissen- schaftliche Zoologie, vol. ii. p. 53. OVUM. 35 These phenomena are confined to the Tn- vertebrated animals, and among them are to be regarded as occasional and exceptional rather than general. Among the Protozoa they may exist to a greater extent than is yet known ; they occur more or less in all the divisions of the Radiata,but more constantly and obviously in the Polypinaand Acalephathan in the Echi- nodermata : among the Mollusca they have been observed only in the comparatively limited classes ofBryozoaand Tunicata: they are almost universal in two divisions of the class Entozoa, viz. the Cestoidea and Trema- toda, but they are altogether absent in the Nematoidea ; they belong only to the lowest division of the Annelida, and among the Arti- culata proper the almost entirely exceptional examples are confined to the class of insects. Nor are the phenomena universal in those classes or orders of the animal kingdom in which they have been described. In some of these divisions, therefore, and in all the others of the animal kingdom, the manner of the reproductive process is ascertained to be direct, that is, by generation from sexual parents, and by development, or in some in- stances by metamorphosis, from ova to sexual individuals ; to which may be added, in some animals, by the multiplication of like indi- viduals, separate or aggregated, by gemmation. But although this general statement is ap- plicable to the present state of our knowledge, we are still too imperfectly acquainted with many forms of the reproductive process to warrant us in affirming that there may not yet be discovered many other deviations from that which has long been familiar to our minds as the more common and direct connection between the ovum and the perfect or sexual individuals which produce it. In the mean time let us endeavour, according to our present information, to determine the true character of theseemingly exceptional phenomena,of which the more important have been noticed in the preceding section. The views first suggested by Steenstrup, in 1842, in connection with these phenomena are unquestionably to be regarded in the light of a discovery, and the attempt to de- prive them of their character of novelty and importance, or to refer them to other pre- viously known general laws, has entirely failed.* It may be that the smaller portion only of the facts on which the views are founded may have been first observed by Steenstrup, and that parts also of these views may be in themselves premature, speculative, or erroneous ; but all discoveries in science are the result of the successive and concurrent observations of a number of inquirers; and no one who has had an opportunity of studying the history of the progress of research into the reproductive function during the last twenty years, will deny that the view which has associated together the phenomena in question under a common principle, has had * See Eel. Forbes’ Remarks, in Treatise on Naked- eyed Medusa;, 1848, p. 83., et seg. a most important influence in modifying the doctrines and in guiding and suggesting the researches of those physiologists wb.o have devoted themselves to inquiries into the origin, early conditions, and zoological affi- nities of the lower animals ; and it may truly be affirmed, that no one could at present enter upon the investigation of any obscure or doubtful department of animal or vegetable production among the lower series of these kingdoms of nature, without making especial reference to the views embodied in Steen- strup’s generalisation. The occurrence of non-sexual multiplication among some of the Invertebrated animals had long been known, as of Polypes, by budding, so admirably described by Trembley in his work published in 1744 ; and of the Aphides, by internal production, discovered by Reaumur and Bonnet ; and of the Nais and Nereis, by external extension, described by Otto F. Midler, in 1800; the imperfect conditions of some of the Entozoa had been detected by Nitsch and V. Baer in 1818: the two forms of the SalptE were known to Chamisso in 1819, who, more than any other observer, appears to have foreseen in these animals the discovery of alternate or dissimilar generations ; but the first observations, from which the peculiar nature and general doctrine of the phenomena now under consideration may be regarded as having been deduced, are those of Sars, on the compound Polype stock of the Medusas, in 1828, and of Rud. Wagner, on the produc- tion of Medusiforrn bodies from a polype (Coryne aculeata), in 1833. From that time, observations followed one another in rapid succession, and continue still to crowd upon us, so as to have changed almost entirely the aspect in which we have been accustomed to regard the development of the lower animals : and it is only necessary to mention collec- tively the names of some of those whose observations have contributed most to extend ami to establish these discoveries in different classes of animals, to exhibit the importance attached to them by zoologists, comparative anatomists, and physiologists of the highest character in our time, such as Dalyell, Lister, Sars, Loven, V. Siebold, Nordmann, Esch- richt, Steenstrup, Van Beneden, Kolliker, Owen, Dujardin, Milne Edwards, Blanchard, Quatrefages, J. Reid, J. Miiller, E. Forbes, Desor, Vogt, Agassiz, Huxley. The peculiar nature of these phenomena as compared with those of the better known and more common form of sexual generation, con- sists in this, that in some animals, in all of which, be it observed, the permanence of the species is secured by the sexual production of ova, the body or individual wbich is developed immediately from the ovum is not, in general, itself the bearer of the sexual organs, but, nevertheless, maintains for a time an inde- pendent existence, or presents the structural and functional characters of a separate or dis- tinct individual ; these characters often dif- fering remarkably from those of the sexual D 2 OVUM. 36 inclivi liials from which the ovum derived its origin ; and that subsequently this individual, or one or other of its successors, has formed in connection with it, eitlicr internally or exter- nally, ami witiiout sexual organs, a new progeny, which may consist of one or of many indivi- duals, svhicli have each of them more or less of the structure and properties of independent animals, and which, however variable their other organisation may he, present tliis in com- mon, that they are sexually complete, and renew the true generative act by the formation of fecundated ova. In some animals it is the im- mediate offspring of the indiviilual develo[)ed from the ovum which resumes the sexual func- tion ; in other animals tliis offspring bears a second brood, or a fhird, and even more suc- cessive generations, before the return is made to sexual re[)roduction. This process of non- sexual production is, in some instances, very analogous to external gemmation ; in some it resembles transverse fission ; and in others it proceeds fi'om the interior of the parent body, in a manner which has been called internal gemmation, but which must be considered as different from a true budding process, and cannot, in a few words, be correctly charac- terised. These deviations, therefore, are pe- culiar in this, as compared with the mode of reproduction in other animals; viz. 1st, that the immediate product of development from the ovum is not usually itself the producer of ova, but that this function is delegated as it were to the sexual individuals, which are the products of its non-sexual generation ; 2nd, that it frc(|uently happens that in place of one individual only resulting from the development of an ovum, several, and even a great multitude of individuals are produced by the non-sexual multiplication of the product of sexual genera- tion ; and, 3rd, that while the several series of individuals proceeding from the various suc- cessive acts of production, may, in one sense, be regarded as different stages of an animal specifically the same, or are together necessary to make up the species, yet their form, orga- nisation, and modes of life are often so dif- ferent, that many of them have frequently been described as belonging to different species and genera, or even to different orders and classes of animals ; and, but for the know- ledge now possessed of their close affinity, as established by their common origin, would still continue to be dissociated from each other in the systems of the zoologist. The doctrine of alternating generation has not, however, been admitted without reserva- tion by some physiologists. In various parts of his recent admirable work on General and Comparative Physiology, and elsewhere*. Dr. Carpenter has expressed his dissent from the views of Steenstrup, both as regards the existence of an alternation of a true gene- rative process and the alleged iiursing function of one or more of the series of individuals so produced; and seems disposed in some measure * In the Biitish and Foreign Medico-Chirur- gical Review, \ ol. i. and vol. iv. to undervalue that author’s researches, con- sidered either as original observations, or as embodying a novel and important generalisa- tion. Dr. Car|>enter regards the phenomenain question as analogous to, if not identical with, those of metamorphosis rather than of genera- tion ; and we are left to supjiose that he does not think the difference essential between such metamorphoses as occur in one and the same individual and those which result in the [iro- duction of a multitude of dissimilar indi- viduals. According to this view, the new animal produced by the non-sexual process is the result of a process of development or growth, and ought therefore to be regarded as formed by budding or gemmation, rather than by an act of generation properly so called. In a recent paper on the subject of Metamorphosis, Non-sexual Reproduction, and Alternate Generation (Zeitsch. fiir Wis- sensch. Zool. June, 1851, [i. IfO.), Leuckart has advocated somewhat similar views, endea- vouring to refer all the instances of so-called alternate generations to metamorphosis ; but this obviously requires that we should change the signification usually given to this term. But the restriction of the word generation to the sexual process of reproduction, though it might be convenient and proper, were we now to have to employ it for the first time, seems somewhat arbitrary in this case, as it is contrary to common practice, and pli3sio- logists have long been in the habit of making the distinction between sexual and non-sexual generation. No new term has been suggested applicable to, or descriptive of, all the pheno- mena in question ; and I apprehend, that, however desirable the change may appear, we must continue to designate the process of non-sexual production as one of “Genera- tion” in its physiological sense, and the series of new beings thus formed as so many “ generations” of individuals in the common or vernacular sense of the term. As Pro- fessor E. Forbes remarks, the alternation of forms is admitted, but not the alternation of generations. The bodies produced by one in- dividual, if they assume new forms and move about as separate and intlependent animals, must be regarded as so many distinct indi- viduals ; and if they are different, and if the one produces the other (even though it may be by a process of gemmation), we must ad- mit that they belong to different generations. The distinction between the formation of a new individual from an impregnated ovum, and that which takes place without the con- currence of sexual organs, is one which, unquestionably, all will feel disposed to re- gard as most important ; but it still remains undemonstrated that all the animal beings which are of non-sexual origin are necessarily formed by a process of gemmation analogous to ordinary growth. It has already been pointed out that the mode of their origin is, so far as it has yet been ascertained, very various; and, at all events, in some of them, there is a wide departure from that which we have been accustomed jo regard as an act of OVUM. 37 gemmation, or simple sprouting of the parent texture. We cannot be too cautious in making wide generalisations in regard to phenomena so various and so imperfectly known as those of alternate or intermediate generation are ; and the only safe course in the progress of such inquiries is to apply terms to the phenomena which are no more than the exact expression of what is well ascertained regarding their nature. Now, who that has observed or studied the history of the two states of the Salpians, and the relation in which they stand to each other, can hesitate to admit that two dissimilar generations alter- nate, and that a different generative process has taken place for the production of each ? or who, knowing the relation subsisting be- tween the fixed marine polype and its free moving medusoid offspring, or that between the larger medusae and tlieir compound polype stocks, would deny to each of these series of beings the attributes of distinct individuals, or regard the productive acts by which they take their origin in any other light than as two dis- similar kinds of generation ? But this seems scarcely more than a question of words. It is important rather to notice that while some of the polypes now alluded to multiply their like (that is polype-forms) by budding, their medusoid progeny also occasionally produce their like (or similar medusoids^ by gemma- i tion ; and surely it is expedient to regard as somewhat different that production of distinct medusoid individuals from a polype stock, which is an advance in its stage of being, and which gives rise to an animal different in structure, mode of life, and functions, from its parent, from that kind of production which is no more than the repetition of the parental form or the extension of its parts. The term nurse, applied by Steenstrup to I the non-sex ual producers, seems inappropriate, 1 and may, in one part at least of his treatise*, I have led him into purely speculative compari- i sons, such as that with the workers among the * gregarious insects ; but in other parts of his 1 essay the author’s speculative views are kept I in strict subordination to the simple descrip- ; tion of the facts. Due allowance ought also to be made by the English reader of this work, for the circumstance that, though an excellent translation, it comes to him through the German from its original language. Less ob- jection would probably have been taken to his theory had the term “ preparing stocks,” or some one conveying a similar meaning, been substituted for that of “ nursing individuals.” Professor Owen also, though admitting in the full extent the peculiar and important nature of the phenomena of alternate genera- tion, objects to the term nurse or nursing animal, as calculated to mislead, and holds the 1 views of Steenstrup, embodied in the phrase ' “Alternating Generation,” to be defective, as ! not affording any real explanation of the na- I ture of the phenomena, or rather, as being no I more than a statement of the facts, without [ I * On Alternate Generations, p. 112. referring them to a sufficiently general law or connecting principle. Professor Owen’s attention had been, before 1813, attracted to the remarkable non-sexual multiplication of the summer Aphides, the structure of which he minutely examined, and had been led to the opinion* that the germs from which the offspring of this non-sexual generation arises are the remains of the ori- ginal germ-substance of the yolk, which have not been applied to the formation of organised textures in the individual immediately deve- lojied from the ovum. Professor Owen has given the name of Parthenogenesis, or Virgin- production, to this mode of generation, and in the very able and ingenious Essay under that title, published in 1849, containing the sub- stance of two lectures, introductory to a most instructive course of lectures on the Generation ami Development of the Invertebrated Animals, and also in various parts of these lectures j-, has communicated a more lengthened exposi- tion of his views. “ The progeny of the im- pregnated germ-cell,” says he, “ form the tis- sues, &c., but not all of them are so employed, some of the derivative germ-cells may remain unchanged, and become included in that body which has been composed of their metamor- phosed and diversely combined or confluent brethren : so included, any derivative germ- cell, or the nucleus of such, may commence and repeat the same processes of growth by imbibition, and of propagation by spontaneous fission, as those to which itself owed its origin ; followed by metamorphoses and eombinations of the germ-masses so produced, which concur to the development of another individual ; and this may be, or may not be, like that individual in which the secondary germ-cell or germ-mass was included.” J He states farther, that the lower the animal in the scale of life, the number of derivative germ-cells and nuclei which retain their individuality and spermatic power is greater, and the number of those that are metamorphosed into tissues and organs, less. The simplest animals are nothing more than nucleated cells, or in the minute and microscopic ones, as Gregarina and Polygastria, one nucleated cell oidy ; the mid- dle layer of the wall of the Hydra he describes as consisting of nucleated cells. In Compound Polypes and Parenchymatous Entozoaa large quantity of derivative germ-cells is retained among their textures or other parts ; and the same is the case at the caudal extremity of the Nais and young Annelida. Professor Owen informs us that he has observed the germs of the viviparous Aphides in the em- bryoes near the simple digestive sac before any organs have been formed for their re- cej)tion, and that when these germs are after- wards included in the tubes which correspond to the ovaries and oviducts, he regards them as comparable to the germ mass in its mi- * See Lectures on the Comparative Anatomy of the Invertebrated Animals, 1843, p. 234. and 3GG. t As published in the Medical Times, vols. xix. and XX. t On Parthenogenesis, p. 5. D 3 38 OVUM. nutest state of division, and as differing from ova in the absence of the germinal cell.* Notwithstanding the attractive ingenuity of these views, and the great weight which all must be disposed to attach to the statements of so accomplished an anatomist, the tlieory they involve or expound, when fully considered, does not appear entirely to remove the veil from the jnystery of alternate generations, nor to afford that satisfactory ex- |danation or generalisation of its nature which might be desired ; for it is to be feared that under the apijellation of nucleated eells, as applied to the structure of the lowest animals, very various kinds of organised structures have been eonfounded by authors, and we are certainly very far from having had de- termined, by actual observation, the nature or souree of the minutely granular masses from which what has been called internal gemma- tion proceeds ; and though it may be admitted that most new struetnres take their origin in masses of blastema, more or less cellular and granular, the relation of these to the germ masses of the ovum are far from being ascer- tained. It may be granted, that in the case of the first brood of Aphiiles formed in the non-sexual way from the first individual im- mediately developed in the ovum, a residuum of germ-cells may have served as the original blastema of their germs ; but when we consider the inconceivably minute portions of this that are to pass to the next and to the successive generations up to nine or eleven, we seem to have to deal rather with a theory of the original pre-existence and “ encasement of germs” than with a matter that we can ever hope to decide by observation ; and in the greater number of the other instances of alternate generation, there is no possibility of tracing the origin of the germs of the new individuals formed by gemmation to the yolk or germ-mass, of which they are regarded as the included remains. Professor Owen has well remarked -j-, that “in the Vertebrated, and in the higher Inver- tebrated animals, only a single individual is propagated from each impregnated ovum. Organised beings might be divided into those in which the ovum is uniparons, and those in which it is multiparous. This is the first and widest or most general distinction which we have to consitler in regard to generation, and in proportion as we may recognise its cause will be our insight into the true con- dition on which Parthenogenesis depends.” But this distinction, notwithstanding its acknowledged imj)ortance, does not carry us any farther into the insight of the essential conditions of the phenomena by the theory of the residual germ-mass originating new germs; for when the greater part of this mass is con- verted into the textures and organs of the embryo directly developeil from the ovum, there is still as great a difficulty as ever to understand what circumstances should de- termine a minute residuum, sujiposing it to * On Parthenogenesis, p. 38. t Loc. cit. p. 62. exist, to form an entire new individual, or a prodigious multitude of individuals, in place of only an additional portion of texture, or an additional organ, which might more nat- urally be regarded as the correlative products of their brethern germ-cells ; or why, in other numerous instances, in which, to all appear- ance, an equal quantity of residual germ-mass exists, no such formation of new individuals occurs. It appears equally fair to suppose that the germs of the ova of all animals must have originated within the ovaries of the female parents from residual germ-cells included in the blastema of these organs ; but no dis- tinction has ever been established between that blastema in its primitive state and that of other organs of the body : and there does not appear to be better reason for consider- ing the germs of individuals formed by gem- mation, as derived more directly from residual ' and included germ-cells, than those of the ovarian ova. I have not adopted the term Partheno- genesis, as applied to the alternate generations, because it implies that this kind of produc- tion occurs in female animals. Now, although the observations of Owen and V. Siebold have shown a remarkable similarity to the female structure in the case of the viviparous Aphides, this is altogether wanting in the other instances of alternate generations ; and this process is strictly non-sexual rather than uni-sexual in its nature. Were it desirable to change the name for this process, the term “ Metagenesis,” suggested and sometimes employed by Professor Owen, seems well adapted to express exactly what occurs in alternate generations, without calling for the admission of any hypothesis beyond that of the new production being an act of genera- tion ; and it seems to me to be the most exact translation in scientific terminology that can be given of the German of Steenstrup in “ Generations-Wechsel.” In a convenient shape it is precisely descriptive of that change of form by generation, or by production of a new individual, which it has been my object to show has been accurately dis- tinguished in the general law of Steenstrup, as different from a mere change of form by growth or by metamorphosis in the same individual. At the same time it is deserving of no- tice, that, among the compound Polypina, the continuous multiplication of individuals proceeds to such an extent, and with such remarkable regularity, as to give rise to com- posite masses, often of very large size, the general arrangement of which bears a con- siderable resemblance to that of plants : and we are led still more to institute a comparison between these animals and plants by the cir- cumstance of the similarity of their continuous growth by the addition of new sets of polype individuals to the extension of the leaves and branches of a tree or ramified plant, and by the correspondence of the occasional forma- tion of sexual individuals on the polype stock OVUM. 39 with the development of flowers. It is not without considerable interest, that the same conditions as to temperature, season, supply of nourishment, &c., seem to determine the one or the other kind of production in both the animal and the vegetable bodies. Many botanists regard the plant as an assemblage of individuals; and zoologists are for the most part agreed as to the distinct individuality of the parts united in a compound polype. But the tendency to spontaneous separation of these individuals, especially in their sexual form, is very frequently exhibited in the animal kingdom, while it is rarely, if ever, met with among plants ; and among the polype tribes, as well as in other examples of alternate generation, the striking dif- ference of form, structure, mode of life, and functions, of some of the sexual indivi- duals developed by non-sexual generation, seem to warn us against extending the compa- rison farther than the admission of the general analogy above adverted to, or, at all events, precludes us in the mean time from drawing any arguments as to the nature of animal pro- duction from that which is as yet only imper- fectly understood in the vegetable kingdom.* These considerations raise another ques- tion on which recent writers are at issue in regard to the theory of Alternate Generations, viz. whether the various animal bodies formed by the non-sexual process within one act of sexual generation are to be regarded as so many indwiduals composing the species, or whether they are to be considered only as the different states of one and the same indi- vidual. I have abstained from entering directly on the discussion of this question, from the desire to avoid the confusion which is apt to arise in it from the use of terms in other than their usual significations. In re- gard to connected animal forms, such as those which coexist in a Compound Polype, less difficulty might be felt than in those instances in which a complete separation of the progeny from its producer has taken place ; but it seems to require a greater departure from the ordinary signification of a common term than is warranted by our present imperfect know- ledge of the phenomena, arbitrarily to de- termine to regard as merely one individual all those bodies which may be formed by a non- sexual process from the product of a single ovum, notwithstanding the great variations in their structure and mode of life, and the com- plete separation and apparent independence to which they may attain. It is unquestion- ably important to acknowledge the integrity and permanence of the species as maintained in the midst of all these variations by gene- ration from an ovum ; but there does not seem to be any obvious impropriety in the instances in question in regarding the species as made up of individuals differently con- stituted among themselves, and produced one out of another by a non-sexual process. The * For farther remarks on this subject the reader is referred to an account of vegetable production, under the Article Vegetable Ovum. term Zdoid suggested by Huxley, or Zoonite previously employed by Milne Edwards and some other French authors, or any such terra agreed upon as implying a relation of affinity among the various bodies included in one act of true sexual generation, may perhaps re- move some of the ambiguity; but I confess I do not think the present state of the inquiry warrants the total abnegation of individuality to the various animal bodies produced in the non-sexual manner.* In reviewing, then, the whole subject of Alternate Generation, it seems to be equally premature to refer the whole of the pheno- mena included under this term, which may hereafter be discovered to be very various in their nature, to a simple process of gemmation or individual development, or to attribute them to the existence of certain powers, such as a germ-force or spermatic power, remaining in certain germ-cells, or to reject altogether the hypothesis of Steenstrup of Alternate Generations, which indeed is little more than the expression of the course of the observed phenomena ; until we shall know more exactly the minute structure of the germ from which a bud arises, and the difference between that and the germ of an ovum, and until we shall be more fully acquainted with the whole structure and series of changes of the various animal forms that have been the subject of consideration in the preceding section. VVe regard it, therefore, as more consistent with the actual state of our kuowledge of the facts to describe the phenomena of Alternate Generation as a peculiar mode of existence belonging to some of the simplest kinds of various classes of Invertebrated animals, which seems to have especial reference to the preparation of the sexual organs ; and of this nature, that the animal immediately developed from the fecundated ovum does not usually arrive at sexual completeness, but has formed from it, by a non-sexual process of production, another individual of a different form, or a succession of them, which finally attain to sexual completeness, and produce the fecun- dated ova that originate the generative cycle ; and the effect of which is, to render two or more successive generations of dissimilar ani- mals necessary to the completion of the species to which they belong. * Some acute and interesting remarks by BIr. Huxley on this subject ■null be found appended to a sketch of J. Bliiller’s discoveries on the Echino- dermata, in the Annals of Natural History, 1851, vol. vii. p. 1. I would also refer at this place to the Lectures of Bl. Agassiz on Comparative Em- bryology, Boston, 1849, as presenting a most en- gaging view of the influence which the study of the metamorphosis of animals, along with the history of alternate generations, must exercise on the systematic views in Zoology and Comparative Anatomy, and I also take this opportunity of refer- ring to some remarks by BIr. C. Spencer Bates in a paper on the Development of the Cirripedia, in the Ann. and Blag, of Nat. Hist, for 1851. vol. viii. p. 331. for a statement of the relations subsisting be- tween the various forms of animals considered in their sedentary and free states, either in individual species or in difi’erent genera or families of the various classes of animals. P i 40 OVUM. Additioml Remarks. — Since the foregoing observations on alternate generation were printed in' August, 1852, the knowledge of these peculiar phenomena and of the whole forms of rei)roduction in various classes of animals has been considerably augmented by several important contributions. A short reference to some of these researches seems necessary in this place, in order to complete our notice of the phenomena referred to. The statements of Stein, referred to at p. 7 of this article, as to the encysted condi- tion of the Vorticellae previous to their under- going multiplication, having been called in ipiestion by Ehrenberg*, the subject has been farther investigated by F. Cohn, with the re- sult both of a full confirmation of Stein’s state- ments, and of its being ascertained that a considerable number of other infusoria are subject to a similar change ; among which he mentions species belonging to the genera Euglena, Frorodon, Chilodon, Notophyra, Trachclius, Trachelocera,and Stentor.f Stein holds it to be fully established that the nucleus of the Vorticella is its true reproductive or- gan. From this nucleus a progeny is formed in two modes, in both of which the parent animal becomes encysted. In one mode the encysted Vorticella is converted into an Aci- neta-form by the prolongation of narrow con- tractile processes of its substance from the external surface, and from the nucleus of this Acineta-like animal successive single ones are protluced by gemmation. In the other form, the nucleus of the encysted Vorticella undergoing subtlivision, becomes converted into the germs or spores of numerous new Vorticellm. This process is probably in these Protozoa the equivalent of a sexual production of ova; and appears to correspond nearly with that which takes place in the production of the Navicella-like progeny from Gregarinae, with this difference, that in the latter case two Gregarina; are united or fused together into a sphere previous to the production of the new progeny or spores. The view of Leydig, therefore j;, that the parasitic infusoria named Gregarinae are onl}' an imperfect or metamorphosed condition of a Filaria, docs not appear to be confirmed. In reference to the Entozoa, recent experi- ments havej furnished ample confirmation of the views now adopted by almost all physiolo- gists, that these animals are the product of a true sexual generation, and that their ova, or embryoes, or larva;, are introduced from with- out into the bodies of those animals which they parasiticaliy inhabit ; while at the same time the knowledge of their migrations and remarkable transformations becomes more and more precise from additional and renewed investigation of their different forms. Flerbst, who had previously failed in some experiments to cause the transmission of the * Bericlit of Berlin Acad, for 1851. t Zeitseb. fUr Wissen. Zool., vol. iv. p. 253. j On Bsorospermia ai\d Gregarinre, in Miiller’.s Arcliiv. for 1851, translated in Quart. Journ. of Micro. Science. Trichina; of the muscles by implantation in wounds of animals, at last succeeded in 1850-51 in causing the muscles of several young dogs to be infected with these parasites by giving them to eat the flesh of a badger which had lived with him for some time in confine- ment,and in which the Trichinae existed in great quantity.* About the same time Kuchen- meister found that by causing young dogs to swallow along with their food a quantity of the Cysticercus pisiformis (of the hare and rabbit), the intestines of these animals were in a few weeks invariably occupied by a Tmnia (T. ser- rata). Von Siebold, who, as has before been remarked, was the first to advance the opinion (in 1844), that the Cysticereus fasciolaris in- habiting the liver of the rat and mouse is only the early condition of the Taenia crassi- colis of the intestine of the cat, has with the assistance of Lewald performed a series of experiments of a nature similar to those of Kuchenmeister, which have established be- yond doubt that various^ kinds of Cysticerei, and also the Ca;nurus of the sheep’s brain, and the Echinococcus vetcrinorum, are always converted into Tmniaeor Cestoid Worms within a short time after they have been transferred, as by feeding, into the alimentary canal of suitable animals. These experiments have also afforded to V. Siebold the means of ob- serving in a most interesting manner the pro- cess of development and gradual conversion of the cystic into the cestoid entozoon. j- Since the publication of V. Siebold’s ex- periments, farther researches on the same subject have been laid before the Academy of Sciences of Paris by Van Beneden and by Kuchenmeister, in Memoirs presented by them in competition for the grand prize of- fered by the Academy in 1853 for the scien- tific investigation of the Development and Transmission of Intestinal Worms.J The observations and experiments com- municated by Van Beneden in this prize essay, and those contained in his highly interesting Memoir on the Cestoid Entozoa, published in the Memoires de I’Academie Royale de Belgique for 1850, have also established in the most satisfactory manner the relation be- tween the encysted or scolex condition and the cestoid form of the Tetrarhynclii ; facts which have also been in part confirmed by li. Wagner.§ Van Beneden has observed the first development of the ova of the Taenia dispar of the Rana temporaria || into the small embryo provided with its three pairs of boring booklets, and has watched with care the ac- tive motions of these instruments, by which * Ann. des Sc. Nat., 1852, tom. xvii. p. 63., and in Quart. Journ. of Micro. Science, No. 3. p. 209. f Zeitsch. fiir Wissen. Zool., vol. iv. pp. 400. 409. See particularly Plate xvi. A. Also in Annal. des Sciences Nat., 1852, and L’lnstitut, No. 974. J See the Report of the Commissioners, by Qua- trefages, in Comptes Rendus for Jan. 30th, 1854. p. 166. § See extract of a letter in Ann. des Sc. Nat. for 1853, vol. xix. p. 179. II Com]5tes Rendus, 1853, p. 788., and in Annals of Nat. Ilist., vol. xiii. p. 167. OVUM. •tl the minute embryoes, scarcely larger than the blood-discs of the frog, penetrate into the tissues or organs in which they afterwards be- come encysted ; thus affording the most direct proof from observation of the manner in which the young of these parasites become established in the internal parts of animals. The head, with the circle of booklets and the four suckers, is then formed at the anterior part of the embryo, constituting now the scolex of Van Beneden ; and this author proposes to give the name of proscolex to the previous embryonic stage. In connection with the for- mation of the head of the encysted animal, it may also he noticed that Stein has observed the three pairs of embryo booklets remaining for a time irregularly scattered over the en- larged vesicular part of the body.* When the encysted animal (Cysticercus) has been introduced into the stomach and intestine of a suitable animal, generally a carnivorous one, it resists the digestive action of these organs, but speedily loses its caudal vesicle, and gradually acquires the new joints which are formed from the head. It is thus brought to the condition of the strobila, if we choose to liken the jointed state of the tape-worm to the multiple or divided polype stock from which medusae are thrown off; and lastly, as the sexual organs become fully developed in each of these joints, beginning in the posterior ones, which are first formed, these are detached one by one, and constitute in the separate condi- tion the bodies named proglottis by Dujardin and Van Beneden. The latter author regards these as alone the perfect animals of the Cestoid, the jointed strobila being only a pre- paring stock; and he adheres to the view, previously referred to in this article, that each proglottis approaches in some degree to the organisation of a Trematode animal. Ac- cording to the views of Van Beneden, there- fore, the different stages of a Cestoid worm are the following : — 1st, the ovum ; 2nd, the first embiyo or proscolex ; 3rd, the cysti- cercus, or encysted vesicular body, or scolex ; 4th, the jointed stock, tape-worm, or strobila; and 5th, the separate sexual individuals, or proglottides. ^ Among the Trematode animals the pro- duction of a succession of new progenies by a process of internal non-sexual ge neration has received full confirmation. Van Beneden has added the important fact, how- ever, that some of the Trematoda are not subject to any process of alternate genera- tion or metagenesis. He has traced the whole process of direct development of the animal from the ovum of Udonella caligorum, a viviparous Trematode with large ova. The alternating generation belongs, according to him, to the Oviparous Trematoda, in which the ova are of small size. In reference to the Compound Medusoid Animals, Siphonophora and Physsophorida, * In observations made on encysted non-sexual round worms, and tlie encysted condition of a ces- toid inliabiting the Teuebrio molitor, and its larva, in Zeitscb. fiir Wissen. Zool., vol. iv. p. 206. it appears from the researches of Leuckart, Kblliker, Gegenbaur and .others *, that the several joints of the connected chains of these animals, as previously conjectured by Milne, Edwards, and others, may fairly be regarded as distinct, though imperfect in- dividuals, some of which are destined for the sexual production of ova, while the free or floating polypine stock remains destitute of sexual organs. The free polypine stock is first developed from the fecundated ovum, and acquires its one or two swimming vesicles : from it there is afterwards formed the long chain of smaller bodies connected together by an extension of the digestive cavity and ex- ternal substance of the animal. Some of these form swimming bells or vesicles with prehensile and stinging filaments ; others are digesting cavities or stomachs, and others, most frequently those last formed in the chain, contain one or other of the sexual products, either male and female among the individuals of the same stock, or distinct sexes on separate stocks. But there is sometimes a combination of the motor and nutritive with the reproductive organs in the same in- dividuals of the chain, which warrants fully their being regarded as something more than the mere repetition of organs belonging to one animal. They are, in fact, the same as the sexual individuals of a compound po- lype ; and in some rare instances indeed they have been observed to become detached and to swim about in the separate condition. In connection with the alternating gene- ration of the Salpte, in the discovery of which the whole series of facts now" under review may be said to have originated, some doubts were in the previous part of the article stated to prevail as to the rela- tion of the sexes in the animals of the aggregated chain. These doubts have now been in a great measure removed, and the knowledge of the whole phenomena of the reproductive processes in these remarkable animals greatly extended by the researches of C. Vogtf and of II. Miiller.+ From these researches it appears that while, as was pre- viously known, the Solitary Salpm are en- tirely non-sexual, the animals united together in the aggregated chain, formed by successive gemmations from one spot of each solitary individual, are hermaphrodite, or possess both male and female sexual products. The ova however, according to Vogt are developed’ at a much earlier period than the spermatic substance : indeed, they are advanced to the condition in which they are ready for fecun- dation, while their producers are still attached as a chain to their solitary gemmiparous parent. The spennigerous organs only advance to' perfection after separation ; and the process of fecundation must therefore be effected in the animals of the attached chain by the * Zeitscb. fiir TVissen. Zool., vol. iv. p. 304., and vol. V. p. 285. &c. ; and Kblliker’s IMemoir on the Siphonophora of Messina. Leipzig, 1853. t ISildcr aus dem Thierleben, 1852, p. 59. j Zeitscb. fur Wissen. Zool., 1853, p.'329. 42 OVUM. spermatic matter derived from detached chains which are frequently floating near them. To this result, no doubt, the currents of water in tlie rcs[)iratory cavity will materi- ally contribute. Since the publication of the first j)art of this article, the general as|)ect also of the questions involved in tlie facts referred to has undergone revision by several authors. The whole doctrine of alternate generation has, it a])pears, been called in (jnestion by Reichert, in a j)rogramme entitled Unisexual Re|)roduc- tion* * * §, which I have not had an ojiportunity of seeing. In his recent very able and in- structive treatise on Reproduction in the llandwiirterbnch der Physiologic, Rud. Lenckartf , though he retains the name of alter- nate generation as designating tlie phenomena referred to, gives the doctrine little place, and seems still inclined to regard this mode of pro- duction rather as a peculiar modification of growtii than as a true generation. He isper- ha[)s right in his remarkj, that physiologists have been too much disposed to separate the phenomena of alternate generation from other forms of proiluction of a non-sexual kind, of which he considers them as only a variety ; the alternation of different forms being, according to him, only a subordinate and not an essential phenomenon. In his recent very interesting work on Animal Moiqihology, Victor Carus(J has allowed more importance to the views of Steenstrnp, ailopting at the same time Owen’s term Metagenesis, as most suitable for the designation of this kind of production. This author appears to me to have made the nearest approach to a correct appreciation of the nature of this jirocess in its relation to the whole phenomena of animal reproduction as at present known. Reviewing therefore finally the whole of the facts and opinions on this subject, I am in- clined to adhere to the views expressed in a previous part of this article, that the pheno- mena of alternate generation or metagenesis ought to be grouped together, and to retain their place as constituting one of the general forms of reproduction among animals ; con- sisting, as they constantly do in a certain number of animals, in the combination, alterna- tion, or succession of the sexual and non-sexual production of individuals all j>roceeding origin- ally from the development of one ovum. At the same time it is to be noted, that this mode of production does not exist in all the species or genera of those tribes of the lower animals among which it has been observed to occur, and that in some it passes by gradual transi- tions into other forms of the generative pro- * Die Monogene Fortpflanzung. Dorpat, 1852. t Article Zeuguny, in the oth and Gth parts of vol. iv. of Wagner’s Ilandworterbuch, 1853. J Loc. cit. p. 979. § System der Thicrischeu Morphologie. Leipzig, 3 853. cess. It is not on that account the same as them. Metamorphosis and Metagenesis, also, as V. Carus remarks, may be combined, but they are different. “ Larvae, the subjects of metamorphosis, arrive at the state of perfec- tion by throwing off provisional structures which belong to their larval condition, but nurses, the subjects of metagenesis, are them- selves entirely provisional structures.” Generation, therefore, or the production of new individuals belonging to a species, may be either of the sexual or of the non-sexual kind. It is only in the Protozoa that the distinction of sex has not yet been discovered. In all other animals the production of new individuals of the species is the result of the development of ova fecundated by spermatic matter. In all the Vertebrate animals and in the majority of the Invertebrate, the development of the ovum gives rise to a single new individual ; in most of them by a continuous process of formative growth, in some by successive stages, or by metamorphosis. In a few Inver- tebrate animals the development of the ovum gives rise directly to more than one individual by what may be named primary division of the ovum. In a considerable number of Inverte- brate animals the production of new indivi- duals sexually perfect is not immediate from the fecundated ovum, but secondary or in- termediate by non-sexual formation from a preparing stock which is the product of de- velopment from the ovum. In such animals an alternation of sexual and non-sexual for- mation of individuals is necessary for the completion of the act of generation or the reproduction of the species. In a few of these animals only one new individual is formed ; but in by far the greater number the product is multiple, thus leading to a great increase in the number of individuals, either in the distinct or in the aggregate form, which have all derived their origin from a single ovum. It is to be observed however, that in some in- stances the alternating generation may co-exist either with the non-sexual mode of multipli- cation or with direct sexual reproduction. In conformity with these views of the rela- tion of the product of generation to the ovum and its progenitors, there might thus be esta- blished the following modes of reproduction among animals — viz. I. Monogenesis, reproduction without known sexual distinction. II. Digenesis, bisexual reproduction. HI. Metagenesis, alternation of sexual and non-sexual reproduction. In each of these nitiin forms of the repro- ductive process the following varieties might also be distinguished — viz. 1. With single progeny. 2. With multiple progeny. 3. By consecutive development. 4. By metamorphic or interrupted develop- ment. OVUM. 43 PART SECOND, Of the Ovum previous to the Com- mencement OF Fcetal Development. I. Anatomical Structure, Chemical Composition, Origin and Formation of THE Ovum in Man and Animals. 5 I. Preliminary and General Comparison of the Ova of Animals. At a time when the analogy and difference in the structure and functions of the ova of various animals were less known than at pre.sent, and especially before the discovery of the true mammiferous ovum, the pheno- mena of development were almost exclusively observed in the eggs of birds ; and conse- quently in the progress of investigations on this subject, and their extension to other animals, the nomenclature of parts of the egg, and nhe interpretation of the phenomena of development, came naturally to be founded on those which had previously been adopted in the study of the egg of the common fowl. In more recent times it has been found that the egg of birds presents in some measure excep- tional characters, as compared with that of the greater number of animals ; and it has thus become apparent that the close limitation of our observations to the class of birds, fruitful as they are universally acknowledged to have been in most important and interesting in- formation on our subject, might tend even to retard in some degree the establishment of the more general laws of typical structure and formative change, which constitute so remark- able a feature of the result of modern em- bryological researches. Still, the convenience of being able to ob- tain the egg of the bird without trouble in all stages of advancement, the familiar knowledge that has so long been possessed of the pheno- mena of incubation, the proportionally large size of the embryo, the difficulty, on the other hand, of making serial examinations of the ova of mammalia, and, though nume- rous and important, the comparatively frag- mentary nature of the observations in this class, and especially in the human subject, make it desirable that we should not too soon depart from the practice, which has so long prevailed, of making the bird’s egg the main foundation of our description of the ovum and formative process in general. But, at the same time, the exceptional structure of the fowl's egg alluded to renders it proper for me to present here, in a connected form, some account of the principal differences among the ova of various animals ; so that we may, in some measure, avoid drawing false analogies, or deducing supposed general laws, which may be premature, or may be rendered inad- missible by the existence of ascertained in- dividual peculiarities, or more extensive dif- ferences among various classes of animals. In the commencement of this treatise (p. 3.), the ovum of animals has been described as consisting in general of two sets of parts, of which the one is formed in the ovary of the female, and the other is superadded to the first after it has left the place of its forma- tion. The first, constituting the ovarian ovum (or ovulum of some authors), consists essen- tially of, 1, the external vesicular covering, or vitelline membrane, 2, the yolk or vitelline substance, and 3, the germinal vesicle, with, 4, its nucleus or macula. As being the most con- stant in their structure and relations, and the more immediate seat and agents of the forma- tion of the embryo, these parts may be re- garded as the essential and most important structures of the egg. The other set of parts, which are subject to great variation in dif- ferent animals, and are only remotely con- nected with the formative process, consist chiefly of external coverings of more or less density, either membranous or calcareous, within which often is enclosed some portion of albumen or albuminous fluid along with the ovarian ovum. They serve the purpose, ill oviparous animals, of protecting the ovarian egg from the hurtful influences of external agents, and, in rarer instances, of supplying ad- ditional nourishment to the embryo ; in vivi- parous animals these parts (as in the chorion of mammalia) serve more important ends, being the more immediate means of establish- ing that intimate organic connection between the parent and embryo, by which a continual supply of materials for the growth of the latter, is transmitted into its body. From analogy, the outermost covering of the ovum of all animals has generally been termed the chorion. r In thus stating the general structure of the ovum of animals, a certain amount of uni- formity, analogy, or correspondence in their several parts has in the meantime been as- sumed ; and the best ascertained facts seemed for long, indeed, to have warranted such an assumption. It will be.for after consideration to determine how far the comparison of the several parts of the ova of diflerent animals proves their uniformity of structure and rela- tion. In some instances it may appear difficult or impossible to discover the correspondence ; and we must therefore be careful not to be led by the attractive nature of a great genera- lization, to confound a merely functional or physiological analogy, with an anatomical, a structural and relational identity. Without entering at present into a detail of the observations bearing upon the foregoing view of the general analogy in structure and function of the ova of animals (which in truth would involve the history of almost all the more recent researches on the subject), it seems proper at this place to call the at- tention of the reader to the most prominent modern discoveries which have laid the found- ation of a more accurate acquaintance with the structure of the ovum, and have also led to the application of improved histological views to the study of ovology.* * It is not intended at this place to refer to the history of discovery in the depai tment of our subject which includes embryological development, in which The first modern discovery, which intro- duced a far greater accuracy into the study of ovology tlian existed previously, was unques- tionably that of the gerniinal vesicle in the ovarian ovum of birds, by Piirkinje, of Bres- lau, in 1825*, an observation which led di- rectly to the ascertainment of the general fact that such a vesicle exists invariably in the ovarian ovum of all animals. The extension of this discovery to a variety of oviparous animals, we may consider as due, in the first instance, to Von Baer and B. Wagner. The next important discovery in chronolo- gical order, which contrilmtcd, in an eminent deuree, to remove one of the greatest difficul- ties in our subject, was that niade^by Von Baer, in 1827, of the minute ovum of mam- malia, or true viviparous animals, f The dis- covery of the nature of the mammiferous ovum was rendered complete in 183-f, by the observation of the germinal vesicle first by Coste and somewhat later but independently by T. Wharton .lones J ; and the knowledge of the mammiferous ovum was greatly ex- tended and confirmed by the obseiwations of (t. Valentin and Bernardt, of Breslau. Hlalpiglii, Wolff, Bollinger, Von Baer and Pander took a prominent part, but only that which belongs to the structure of the ovum itself. * This discovery was first announced in a small work, entitled Symbok-e adOvi Ilistori.am ante Incu- bationcm, Auct. Joann. Evang. Purkinje ; jirinted at Leipzig in 1825, on the occasion of the celebration of lilumenbach's Semisecular Jubilee. A second edi- tion in 4to, with two lithog. plates, appeared in 1830. Purkinje is also the author of the Article Ei in the Berliner Kncyclopiedisches Worterbuch, in 1834. t See the Epistola de Ovi Jlammalium et Hominis Genesi, Auct. Car. Ern. Be Baer, published in 4to., at Leipzig, in 1827 ; and the intere.sting Com- mentary on or Supplement to the same iiVlIeusinger's Journal ; and the translation of both of these writings in Breschet’s Re'pertoire d’Anatoinie ct de Physiologie. 4to. Paris, 1829. As 1 shall have occasion to "return to the history of this dis- covery, I will not enter on farther details here ; but it is right to state that Messrs. Provost and Bumas may in some measure be considered to have shared in the merit of the discovery ; as, in an extended and highly illustrative series of experiments, instituted by them as early as 1824, they were, led to the conclusion that the ovules of mammiferous animals, of extremely minute size, were really contained in the Graafian follicles previous to conception ; and they even appear to have twice seen in the contents of very .advanced follicles, a small spheric.al body which could be no other than the ovule. See An- n.al. des Scien. Nat., tom. hi., 1824, p. 135. But Von Baer first demonstrated this body with })recision, and explained its relations to the follicle, cSiC. J Coste’s discovery of the gennin.al vesicle in the r.abbit, was communicated to the public in the Gonqites rendu,-, for 1833 ; it is fully described in his Becherches sur la Generation des Rlammiferes, &•('. ; 4to. I’aris, 1834. In 1835, Thomas Wharton Jones read a paper to the Royal Society of London, containing an account of his observations on this vesicle in the mammiferous ovum, made without a knowledge of those of Coste in the autumn of 1834 ; but this paper was not printed in the Transactions of th.at year. It was afterw-ards published in the Lond. Med. Gazette, in 1838, p. G80.' This dis- covery was confirmed and extended by Valentin and Bernardt, whose obsei-vations are recorded by the latter in his w'ork, Symb. ail Uvi Mamm.al. Hist, ante Pra;gnationcm, Vratisl.avi.'u, 1834 § See G. Valentin’s Haudbuch der Entwickclungs- Tlie nature of the germinal vesicle it.self next attracteil the attention of ovologists, anil a farther addition to the knowledge of its structure was made by Rudolph Wagner, of Gottingen, in 1835, by the discovery in it of a minute particle or inas.s of fine granules, to which he gave the name of macula germi- nativa, or germinal spot.* The subsequent researches which that author instituteil on the earliest condition of the ovula in the whole series of animals, contributed," more than any others of the same 'period, to establish the doctrine of a general uniformity in the struc- ture and mode of origin of the ova of animals. -}- Although it appeared, from the researches of R. Wagner, and has been made still more apparent from late observations, that in several classes of animals the germinal macula loses its determinate foim and is subdivided and diffused, as it were, in the germinal vesicle, yet the more circumscribed form of this body, in its earliest condition, and its general preva- lence, as a constituent part of the vesicle in almost all animals, seem to indicate the analogy of that vesicle with the true nucleated cell of other parts of the animal body. After the general nature and structure of the ovum had been ascertained by the several discoveries now mentioned, numerous and important researches followed one another in rapid succession, giving greater extent, minuteness, and accuracy to, and in some instances modifying and correcting, the know- ledge previously acquired. Among the authors of these researches, besides those already mentioned, the names of Rathke, J. Muller, Prevost and Dumas, Barry, Reichert, Bi- schoff, Kblliker, and Vogt, occupy the most prominent place. Of these, and others, more special mention will be made in the progress of our history of the ovum and its develop- ment. But, as my present object is to place before the reader only the principal disco- veries which may be regarded as the ground- work of the scientific knowledge of our subject, I will only farther call attention at this place, to the influence which the ob- gescbiclite des Mensehen, &c. ; 8vo. Berlin, 1835, at p. 14. The part of this work relating to the structure and formation of the ovum, was translated and published by Br. M. B.arry, in the Edin. Med. and Surg. Journal, No. 127. * The observations of R. Wagner on this subject, were made towards the end of 1834. This discovery w-as first published in the 1st Edit, of his Lehrbuch der Vergleich. Anat. 8vo., Leipzig, 1834^ — 35, pp. 320 and 352, and in Muller’s Archiv. for the latter year, p. 373. •j- Ilis more extended I'esearches are described in the -work entitled, I’rodromus Historic Genera- tionis Hominis atque Animalium ; folio, Leipzig, 1836. With two copper-plates and very numerous figures. These and the researches of Valentin, are, with reference to the o-vum, peculiarly interesting and important as the immediate precursors of the Microscopic Researches of Schwann. See also, the Beitrage zur Geschichte der Zeugung und Entwic- kelung, by R. Wagner ; publi.shed in the Trans, of the Roy. Bavar. Acad, of Sciences, 4to., Munich, 1837. R. Wagner is also the author of the Article Ei in Ersch and Griiber’s Encyclopcedie. OVUM. 45 servations and doctrines of Schwann, as to the cellular origin and constitution of the textures of plants and animals, published in 1838, have exerted on the progress of ovo- logy and embryology. In accordance with his general views, Schwann regarded the ovarian ovum as constituting an organised cell, of which the vitelline membrane is the outer cell-wall, the yolk substance the con- tents, the germinal vesicle the nucleus, and the macula or maculae the nucleolus or nucleoli.* While the observations of Schwann do not present us w’ith any very important new facts as to the structure of the ovum in particular, and although it may be necessary even to modify, in some degree, the view we should now, with our increased knowledge, be dis- posed to take of its relation to other organised cells of the economy, still it cannot be doubted that the great generalisation matured by this author has exerted, and stilt continues to exert, upon the progress of discovery and the scientific aspect of our subject, a no less re- markable influence than that which has been ap[)arent since its first promulgation, on al- most the whole range of physiological ana- tomy ; furnishing the key to the structure of the ovum itself, laying the foundation of the histological laws of development, bringing a vast amount of observed facts under a con- sistent doctrine, and stimulating and guiding the embryologist in new paths of research.-f- * Schwann, after hesitating somewhat whether to regard the entire ovum or the germinal vesicle as a true cell, gave the preference to the above vie;v, chiefly from a consideration of the manner in w Inch the ovum rvas believed to be formed, and its corre- spondence, as he conceived, with the invariable and necessary mode of formation of cells in general. Tliese latter views have themselves undergone some modification since the publication of Schw'ann’s Researches, and we shall probably find (as will after- wards be more fully stated) that a study of the structure and mode of production of the ova in a variety of animals, may render it irecessary to mo- dify also the comparison ofthe parts of the ovum to the organic cell, adopting rather the view' of K. Wagner and Henle, according to which the germinal vesicle is regarded as the true cell, and the other parts of the ovum as of the nature of superadded structures. t Mikroskop. Untersuch. iiber die Ubereinstim- mung in der Struktur und dem Wachsthum der Thiere und Pflanzen, von Dr. Thomas Schrvaun. Berlin, 1839. The interesting Researches of M. J. Schleiden, on the cellular structure of Plants, en- titled Beitrage zur I’hytogenesis, published in Muller’s Archiv. for 1838, immediately preceded those of Schwann ; and they may be considered as forming in some measure, along -with his, the basis of modern histology; the researches of the latter author were independently made, and an extract of them published in the beginning of 1838, in Froriep’s Kotizen ; and the two first parts of his fuller treatise were sent to the French Academy, in August and December of 1838. An interesting analysis of both these works in the British and Foreign Medical Review, vol. ix. for 1810, made their contents generally known in this country ; and an excellent translation of them both by hlr. H. Smith has since been published (1847) under the auspices of the Sy- denham Society. It may be observed, however, that the great and important generalisations which Schleiden and Schwann have, with so much merit. The most important general facts that have been ascertained in regard to the ova of ani- mals may now be stated shortly as follows : — 1. The ova of animals begin to be formed in the ovary of the female parent at an early period of life, and are produced more com- monly in vesicular, more rarely in tubular, cavities or ovisacs of these organs. 2. In those instances, in which it has been po.ssible to detect the earliest stages of forma- tion, the ovum appears very generally to take its origin in the form of a minute spherule or vesicle. This soon enlarges, and is converted into a nucleated cell, which forms the germinal vesicle, and this remains as a constituent jtart of the ovulum, till the latter is about to leave the ovary, or till the first formative changes cointnence. 3. The vitellus, or yolk substance, begins to be formed a little later. It is gradually accumulated, either in the vicinity of or round the germinal vesicle, in some rarer instances being produced in a separate organ ; it con- sists of an albuminous fluid in which are suspended a large quantity of granules and oil spherules, or of larger corpuscles, having the form of non-nucleated simple cells. The structure of the yolk substance is subject to considerable variety. 4. The yolk substance and germinal vesicle are together enclosed, in the mature state of the ovarian ovum, by an almost structureless vesicular vitelline membrane, which in most animals is formed later than the other parts, in some at an early period, in others com- paratively late, and which is not, therefore, to be invariably regarded as a true cell-wall, or as an original part of the ovum. 5. The germinal vesicle presents several of the characteristics of a true organised cell ; the macula, or germinal spot, has in many animals the form and relation of a nucleus ; but in some, the subdivided structure of this macula, which succeeds in the progress of formation of the ovum, causes it to lose its simple nuclear character. 6. When the ovulum, or ovarian ovum, attains maturity, it generally leaves the place of its formation in the ovary, and about the same time — in some animals before, in others after it — the germinal vesicle disappears, bursts, or dissolves. In the greater number of ani- establisked, may in some measiu-e be regarded as the fulfilment or amplification of, and true deduction from, a variety of detached observations, which had been accumulating, in regard to both kingdoms of nature, for some years, more especially after the im- provement of the achromatic microscope had given increased facility and precision to the minute ex- amination of the tissues ; such as the discovery of the nucleus of the vegetable cell by Robert Brown, in 1831 ; the discovery of the cellular structure of the chorda dorsalis by J. kliUler ; the observations of Ilenle on epithelium, of Valentin on several similar subjects, and. of Turpin and Mirbel on plants, together with the observations previously referred to on the ovum of animals itself. But these detached ob- servations had not led to any important general vriews before the publication of the Researches of Schleiden and Schwann. 4G OVUM. mals, it is uncertain wliat becomes of its sub- stance. 7. In tlie greater niinibcr of animals the ovum acquires some additional parts, such as albumen, external coverings (shell, chorion &c.), in its descent through the passages of the female parent after leaving the ovary ; in some animals an external covering corre- sponding with the chorion is alreatly forinetl in the ovary. 8. When the spermatie substance of the male parent has come in contact with the ovum, so as to exert its peculiar fecunilating influence upon its germinal part — an action which in a few animals occurs before, but in the greater number shortly after it has left the ovary — the first of the series of changes which follows, and is preparatory to lawng the foundation of the new being, consists, in almost all animals, in a peculiar process of tlivision, cleavage, or segmentation, which affects either the whole yolk, or a part of it, or that portion only in the vicinity of which the germinal vesicle has before been situated, anil in which the rudiments of the embryo afterwards make their appearance. This sub- ilivisiou proceeds continuously, till the whole germinal part of the yolk is reduced by it to a nearly uniform mass of corpuscles, or struc- tural elements of microscopic size, which ge- nerally occupy or are spread over more or less of the surface of the yolk mass within the vitelline membrane. 9. The rudiments of the embryo, and its accompanying organised structures in the ovum, when such exist, are first formed in the ecutre of a layer of nuclcateil organised cells, named by I’auder Blastoderm or ger- minal membrane, the formation of which re- sults more or less directly from the process of segmentation above referred to. The dis- ap[)earance of the germinal vesicle when the ovarian ovum arrives at maturity, the influence of fecundation acting about the same time, the process of yolk-segmentation which im- mediately follows the latter change, and only occurs as a consequence of fecundation, and the formation of the germinal membrane or blastodermic layer of cells, in which the seg- mentation results, are successive phenomena of change in a fruitful ovum, which undoubtedly stand in some very immediate and close re- lation to each other ; but the exact nature of that relation is still involved in some degree of obscurity. In some animals the process of yolk-segmentation seems either in itself to be a process of rapid cell-formation, or to be accompanied by it ; while in other animals (chiefly those highest in the scale), the seg- mentation is only the immediate prelude to the generation of the true nucleated cells, v/hicli afterwards constitute the blastoderm. 10. The centre of fcetal develoimient is co- incident with the place of the germinal vesicle in the mature egg, and with the centre of the blastodermic layer of cells ; and it would ap- pear, also, that the principal axis of the em- bryo is coincident with the line of first divi.siou of the germinal part of the yolk in the com- mencement of segmentation ; but it is yet undecided wdiat jtart the germinal vesicle or its nucleus or macula more immediately take in the segmenting process, or in the origina- tion of the true embryo-cells ; and in the higher animals, at least, it is still uncertain whether or not these embryo-cells are the direct progeny or descendants of the germinal vesicle, or its nucleus. The germ spot, the centre of the first segmentation, and the centre of embryonic formation, constitute, therefore, a constant point in all animals, which may be termed the germinal centre of the ovum. Divisimi of the Ova of Animals into Groups. — Although the researches of modern ovo- logists thus enable us to assert with confi- dence the general similarity of structure in the ova of animals, and to point out general features of correspondence in the phenomena which they exhibit in their first origin, pro- gress to perfection, and conversion into the rudiments of the new being ; yet it must be admitted that very imjiortant differences are also to be observed among various ova, more especially when they have reached a state of maturit}'. In what has previously been af- firmed, therefore, of the similarity of animal ova, it is to be understood that uniformity of a general kind only is implied ; and even that correspondence is demonstrated not so im- mediately, in many instances, by the examina- tion of the fully formed ova, as by their careful comparison, at different stages of their growth, and more especially in their earlier condi- tions. The more important of these differences are those which are related to the nature of the germinal portion of the ovum, as com- pared with the rest of its parts ; and a con- sideration of these differences, in so far as they have yet been observed, appears to lead to a division of the ova of animals into three principal groups, as follows : — First group. — In a certain number of ani- mals, some of which are viviparous, others ovi- parous, the ovum is for the most part of proportionally small size, sometimes very mi- nute, as compared with the full-grown parents, and of very simple structure ; the yolk sub- stance is entirely composed of elementary granules, or minute and simple spherules; the process of segmentation affects the whole mass of the yolk, and the germinal or blasto- dermic layer, resulting from that segmentation extends from the first over the whole surface of the ovum ; the whole of this layer con- tributes at once to the formation of the rudi- ments of the embryo and its accompanying organised structures ; the whole yolk, or ovu- lum, in fact, is germinal, or is converted into the parts of the future embryo. Such is the nature of the ovum in mammalia, and among the Invertebrata, in most Mollusca, Entozoa, Echinodermata, Acalephm, Polypes, and a considerable number of other tribes. Second group. — In another set of animals, the great majority of which are oviparous, the ova are proportionally of the largest size ; the yolk substance consists very obviously of OVUM. 47 Fig. 31. Diagrammatic representation of the three principal kitids of ovarian ova, in sections (the relation of size not, however, being maintained). A. Mammiferous ovarian ovum ; z. zona pellucida or vitelline membrane of some authors; v. granular 3'olk substance ; g. germinal vesicle, with its nucleus or germinal spot ; a', young ovum of a molluscous animal. B. Young ovarian ovum of a bird ; v. m. vitelline membrane ; v. large yolk corpuscles of two kinds — viz. those of the yellow external part, and those of the cavit}^; g. germinal vesicle without spot or nucleus, but granular diffused macul® ; v. d. small granular yolk substance forming the vitelline disc. c. Ovarian ovum of a batrachian reptile ; v. m. vitelline membrane ; v. d. vitelline disc, or forma- tive yolk-substance deeply coloured, and surrounding the large granular yolk substance, in one nearly entirely, in the other, 0, 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. The germinal vesicle in the ripe ovarian ovuluni, is situated in the centre of the granular disc, and after its disap|iear- 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 conseijuently 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 enibiyo 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 develojiment in the whole class of birds, with some differences in scaly rej)- 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 3olk, 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 les.s (piantity, are subject to considerable varietv, and exhibit less of the cellular structure which characterises the ova of the previous group. The germinal layer occu[)ies a larger portion of the surface of the yolk than in tlie iarge-yolked 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 jiart, 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, lusecta, 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 [)hysiologists 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 •18 OVUM. of late attracted considerable attention, and appears to have been first clearly stateil by lleicliert in 1810, and afterwards in 1813*; and in accordance with the views of that au- thor, we may with projiriety distinguish the formative (or germinal) from the nutritive parts of the yolk. In the fowl’s egg, for ex- ample (in which it must he admitted these two parts were long confoumled together), the cicatricula, togetiier with its so called nucleus, and a part, perhaps, of the lighter- coloured substance which occu])ies the centre of the yolk and the canal extending from it to the cicatricida, 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 (juantity, and tlie whole of the yolk substance may be looked upon as directly I'ormative, or as analogous to that which forms only the cicatricula of the fowl’s egg. Among more recent writers the distinction of these ])arts has been piarticularly insisted upon, and illustrated by M. Costef, and also by Messrs. Prevost and Lebcrt.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 reipiired being provided in the egg itself, and dctaeheil 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 [Kircnt in the placenta, or in some analogous structure, which accompanies utero-gestation. The smaller proportional size of the nutri- tive ])art in Batrachia and Osseous Fishes (though most of these animals are truly ovi- parous), may be attributeil 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. () * Kntwickelungsleben im Wivbelthierreich ; 4to. Berlin, 18-10 ; ami in Beitriige zur Kenntniss lies hentigen Entwickelungsgesdiichte ; 8vo. Berlin, 1813, p. 22. t Cnurs il’Embryogthhe Compared, tom. i. Paris, 1837 ; and Ilistoire gen. et partic. du Developpement de rilomme et des Aniinaux, Paris, tom. i. 4to., 1818. j In Annal. des Scien. Nat. for 1814. 3rd Ser. tom. i. p. 103 and 2G5. § At tlie same time it is to be kept in mind that there are exeei)tions to these relations, wliich make it extremely difficult to state any general law of conneetion between the structure of the ovum and the mode of gestation and ]dace of development of the emhrvo ; 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 Iiy no means otiered as exhausting tlie divisions which might he formed of the ova of animals, but rather as bringing forward prominently the most remarkable characteristics of those of vertebrata. It is ^lot improbable that a more accurate acquaintance with the structure of the ova in the animals thus grouped, and more especially of the luvertebrata, may lead to some considerable modifications of the divisions here adojiteil; hut the main distinction upon whicli tlicy are founded is so important, that even with our present incomplete acquaintance with tliem, 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 groiqi, SmciH-yolkcd ova, as in Mammalia ; 2nd group, Lurge-yollced ova, as in Birds, Scaly Reptiles, and Cartilaginous Fishes; 3rd group, Middle-sized yolhed 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 tlie relation of their parts. Size of ova. — In addition to what has been said on tliis subject in the previous section, it may farther be remarked that, in the second ami thiril groups, the size of the ova of dif- ferent genera and species is to a certain extent projiortional 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 wliich, 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 tliat of the parent animal, from the smallest hum- ming bird up to the ostrich, or the still larger egg of the AEpyoriiis, an extinct bird, of which some of the hones, along with the eggs, have recently been discovered in Madagascar.* that of animals which are generally oviparous, it is retained in ihe oviduct or uterus of the female during a part or even the wliole of the time of foetal develop- meiit; and there are also exceptions in the third group — viz. that of batrachia and osseous fishes as in tlie Land Salamander and Viviparous Blenny. To tills 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 tlie size of tlie ovum and tlie mode of gestation. The Marsupiata also, and tlie hlonotremata 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 tlie 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 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 . — > — of a "rain. 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 lbs., 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 lbs. 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 lumpus recently measured by myself), at 9 lbs. 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 manimiferous ovum, the germinal vesicle is about or 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^ quarts 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 Apterj-x of New Zealand, which produces a proportionally very large egg. Supp. 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 lbs. 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 - 0 001 500 45,000'0 900,000. Fowl - - 900-000 1500 (iOO'O 20,000. Osseous fish - 0-135 22,300 0-1 06,500. 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 Ilolibut or Hippoglossus, of 156 lbs. 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 w hich 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 jiroductive. 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 fow 1, 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 lbs. or ten times the weight of the whole animal; and, if * The Article “Zengung” by Leuckart, con- tained in tw-o parts of E. Wagner’s Handw-orterbucli del- Physiologie, and which I hav-e only received since the above w-as written, may be consulted as containing fuller information on the same and the following subject. E 50 OVUM. tlie product of different successive years be taken togetlier, 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 he seen in the ovary of tlie common fowl, and I find it to amount to .30,000 or 40,000. A great many of these ovula must, therefore, he un[)roduc- tive in the higher oviparous animals, their germs either remaining undeveloped or being absorbed in the ovaries. In mammalia, and in the human species, altliougli 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 tlie ovaries, serve for pro- duction of the offspring, it is known that a considerable number is discharged from the (iraafian vesicles of the ovaries in the unim- pregnated state. Thus, in the human female (as w'ill 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. Titere 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 thegallinae and others allied to them, and the greater disparity at the opposite ends, as in the seafowl.* In 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 chelonia 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-albuminous substance, in which either no calcareous matter, or only a small (|uantity 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. Fig. 32 External forms of different eggs of Birds and Beptiles. A. Batrachian reptile, frog or toad ; spherical shape, the dark yolk witliin, the gelatinous albumen externally; swollen by imbibition of water. B. Triton or Salamander; elongated external membrane, coloured spherical yolk within. c. Oval of unequal cuiwes 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 tubular processes project- ing from the middle of the two ends, which probabI\' serve the same purposes as the differently shaped appendages of the ova of the shark and skate. Fig. 33. External form of ova of Oviparous Cartilaginous Fishes. A. Ovum of tlie common skate fish, a poiiion 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 25 — 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 quantitj' and softer, and the twisted chalazm 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, anil 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 coyering of the oyum is membranous, homogeneous and transparent, and of an elongated oyal 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 invertebrato, more especially among insects and mollusca, wdien 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 Salamaudres Aquatiques ; Milan, 4to. 1821. I have often confirmed his ob- servations on this process in ponds, and with animals kept in vessels in the house. E 2 52 OVUM. ash-coloured. In the land-newt, which is ovo- viviparoiis, 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 w'hile 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, not 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 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 (irojecting part of the capsule, or towards the external surface of the ovary, being there imbedded in a layer of granular cells, the discus 2iroIigerus of Von Baer, which lines the ovica[)Sule, 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. SOL A. Hancock on the Nidification of the Gasterosteus aculeatu.s, &c., in Annals of Natu- ral History, Oct. 18.o2. t See a paper b}' Hr. Davy on the chemical pro- pcilies of the vitellus of Osseous fishes in Trans. Iiov. 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 Cristatdla mucedo. (From Turpin, Annal. des Scien. Nat. 1837. tom. 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 to the organ, however varied in its structure and relations, in which the ova are formed. As already indicated, however, it is to be observed, that in the higher animals, it is only the ovule, or yolk, with its germinal vesi- cle and enclosing membrane that is formed in the ovary, while the external or cortical parts of the ovum are added to these in their descent through the female passages after leaving the ovary. There are some examples ill which it would appear that the whole Fig. 35. Relation of the ovaries, ovum, oviduct and uterus in 3Iammalia. A. Gravid uterus, &c. of the rabbit, ten days adv.inced in pregnancy ; at a, right and left ovaries, four corpora lutea in the right, two in the left; I'h, fimbriated openings of c' c, the Fallopian tubes; d'd, the right and left cornua of the uterus; d', with four dilatations from contained ova, ed 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 ^tth 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. Bleckel’s paper, afterwards referred to, Zeitsch. fur 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 cireuin- 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, wnich 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. 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 neighbomung 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 sm-face 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 tlie 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 CO OVUM. comparatively large veins which constitute the hollow spaces. The ends of these veins, then, look towards the inner surface of the incnihrane ; and the appearance of a divided cavity in some of the sup])osed 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 1 had the means of ascer- taining whether anything of the same kind exists in other reptiles with large yolks. In the skate I 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) iiresent 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 may be 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 ah 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 Ui 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 1000 grains. Double-yolked eggs are, as might be expected, much larger, reaching often a weight of 1400 grains, or 3f 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. Fowl - Length Breadth (in inches). 2-25 1-7 920 Weight (in grains), nearly 2 oz. Duck - 2-5 1-75 1100 2i oz. Turkey 2-7 1-9 1.300 3 oz. Goose - 3-3 2-4 2000 6 oz. OVUM. 61 men 58, the yolk 311, and the shell with its lining membrane, lOl- 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 16J- 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 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. 304, and Annals of Philos. 1821. t 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 : — Fresh Incubated Shell and membrane egg. - 10-67 egg- 10- Albumen, &c. - - - - 17-8 19-4 Oily matter, &c. - 18-83 6-5 Water - - 52-7 47-1 j f Water - 5-6 1 b Oily matt., &c. 1 1-4 J 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. se'r. tom. ix. p. 174. Water, about - - . 53- Vitelline, albumen, and protein com- pounds ----- pG-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. 62 OVUM. process, and in eggs that have been long kept, the space lias 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 ; 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 bas 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 tbe air space increases, the whole spe- cific gravity will be lowered. Tbe specific gravity of the albumen and yolk differ in a considerable degree; that of the yolk , though containing tiie largest amount of solid matter, being lowest in con- sequence of tbe 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 difl'ers 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 ; and, among others, the chalazae have been supposed to balance tbe yolk in sucb 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- * Rccherclies Anat. et Physiol, sur rOinf des Vertebres, Mem. Couronn. ; published in Blem.des Savans Etrangers de I'Aead. Eran. 1850. nomenon. The measurements of the specific gravity of diflerent parts of the egg by Messrs. J^tg. 44. Poskwn, form, and attachment of the chalazce, yolk, i and cicatr icula, as shoicn by sections of fowls’ eggs !| boiled in different positions. ji A. Section of an egg, boiled on its side : b, with j the narrow end up ; c, with the wide end up i These figures show the tendency of the lighter part ji of the j^olk, on the surface of -which the cicatricula, i! c, is situated, to be buoyed up and to expand in the i white, at the same time that the movements of the l| yolk are to a certain extent limited by the attach- || ment of the chalazre ; a, air-space. I 63 OVUM. Baudrimont and St. Ange* are quite confir- matory of this view. They are as follows ; — Sp. gr. of the External albumen - 1041' „ Internal albumen - 1042'5 „ Whole yolk- - 1029‘5 „ Upper part of yolk - 1027' „ Lower part of yolk - 1031‘5i- The chalazae, being of greater specific gra- vity than even the inner layer of white, always float lowest ; but, being attached to the yolk near its poles, they hang down from these points. All these circumstances may be illus- trated very clearly by sections of eggs that have been boiled in different fixed positions, as on the side, on the large and small end ; in which it will be found that, while the chalazae exer- cise a certain control over the position of the yolk, that portion of its surface containing" the cicatricula rises higher and expands more fully within the white than the opposite portion, while the chalazae gravitate towards the lower side. (See Jig. 44.) Structure of the external parts of the egg. — The shell of the bird’s egg is composed of a delicate basis of organised animal matter im- pregnated with the calcareous and earthy particles, the arrangement of which approaches to a crystalline appearance, but is probably of a different nature. This substance is porous, like concreted gypsum-plaster, and allows of evaporation and the mutual diffusion of gases through it in the same manner as that sub- stance ; while, by its strength and rigidit}', it affords protection and support to the softer parts of the egg during incubation. The pores of the egg-shell may be easily stopped by any greasy or oily matter, or by melted wax or varnish ; and then all passage of moisture or air through the shell being pre- vented, the development of the embryo be- comes impossible. Eggs that have been oiled cannot, it is well known, be hatched ; but eggs may be kept for a considerable time — weeks, or even for months — by immersion in lime- water, which impedes the evaporation and the access of air, which might favour putrefaction, while the natural condition of the contents is thus preserved. The shell in most eggs is slightly dimpled externally, with small depressions visible to the naked eye ; but these are not the open- ings of the pores through which evaporation or exchange of gases takes place — these being much more minute and numerous — but merely the indication of depressions caused by the largely villous structure of that part of the oviduct (uterus) in which the calcareous shell is deposited. On removing the earthy matter by means of a dilute acid, the animal basis remains as a * Op. cit. t Dr. Wm. Aitken has, at my request, repeated these experiments, and has obtained results in ac- cordance with the above statement. He found the unboiled yolk to float indifferently in any part of a saliiTe fluid of specific gravity 1035. By boiling, the specific gravity was reduced to 1031," and in both cases the side with the cicatricula floated upper- most. The upper half, containing the cicatricula, had a specific gravity of 1030 ; the lower half, 1032. slightly coherent, cellular, organised structure, the form of the small compartments in which corresponds with that of the calcareous par- ticles of the shell (see Jig. 45. c). The in- Fig. 45. Structure of the shell and shell-memhrane in the Foivl's egg. A. Lining membrane of the shell ; a, thick matted or felty portion ; b, thin shred of the tom margin, showing the peculiar fibrous tissue of which the various layers are composed. B. Outermost layer of the same, which is incor- porated with the shell ; some of the angular cor- puscles of the shell l3ung upon the fibrous substance and firmly united with it. c. Small portion of the calcareous shell, which has been steeped in dilute hrxlrochloric acid, show- ing the remains of opaque calcareous substance in the centre, some portions of it exhibiting a granular aspect, and round the margins the animal basis or matrix from which the calcareous matter has been dissolved, presenting an irregular granular or almost amorphous aspect. Here and there clear oval cells are seen, as at a cr. ternal surface is irregular and flocculent, and adheres very closely to a different kind of membrane which lines the shell. In those instances in which the shell of eggs is coloured, the pigment substance, of various hues, is generally deposited in cells, which are strewed uniformly or in patches over the external surface of the calcareous .shell. In some other instances, however, the 64. OVUM. colour seems to be merely a uniform tinge of the outermost layer of calcareous matter.* The lining membrane of the shell is a peculiar fibrous, interwoven structure, tlcpo- siteil in laminae of some thickness and tough- ness, which is readily divided by tearing into two layers over the whole surface of the egg — an outer, thicker, aiid denser, adhering firmly to the inner surface of tlie shell; and an inner, thinner, smoother, and of finer texture, which may be easily withdrawn from the outer one, and which naturally separates from it at the air-space ; but both the outer and inner layers of this membrane may be torn into a number of thinner lamina;, all agreeing in their minute structure. By microscopic examination, this membrane is found to consist of a closely-interwoven network of peculiar fibres, which are of va- rious sizes, generally between -.^^th and _-i_th of an inch in diameter ; the larger fre- (luently branching into or giving off smaller fibres at acute angles, the sides rendered un- even by minute projections or knots u{)on them (not represented in the figure) ; the larger fibres are of a somewhat flattened or ribband-like form. The external layer of the membrane contains the largest fibres. These fibres appear to be analogous in their che- mical nature to those of the elastic yellow texture, not being soluble in strong acetic acid ; but they do not coil up in the manner of the elastic tissue {see Jig. 45. a). The parchment-like coverings of the eggs of serpents and lizards, which have no calca- reous shell, seem to be composed of a greater number of layers of the fibro-laminar te.xture now described. The albumen, or white of the egg, compre- hends several layers of glairy, albuminous, semifluid substance deposited round the yolk, the chalazm, or grandines, or twisted coixls, and the condensed layer of albumen, forming a thin membranous investment immediately over the yolk membrane. In a perfectly-fresh egg, or in an egg taken from the oviduct pre- viously to" its being laid, the whole albumen has the consistence of a moderately-firm jelly ; but very soon the outer part becomes fluid, and allows of the freer motion of j the parts within the shell. This solution of the albumen proceeds to a greater extent after some hours’ incubation, especially over the cicatricula. The deeper part of the albumen, or that next the yolk, is more dense in consistence. No part of it, when unchanged by reagents, presents any sensible structure either to the naked eye or when viewed microscopically. If, however, the soft contents of a fresh egg, or one removed from the oviduct, be taken from within the shell, and thrown into water either [)ure or with a little acetic acid mixed with it, a slight turbidity or coagulation of the albumen takes place on the surface, which brings out the appearance of a spiral arrange- * See the works of Hewetson and others on the Eggs of Birds. Cams and Otto, Erlauterungstafeln der Vergleich. Anat. part v. ment of laminte ; and in a boiled egg these lamina; may be torn in great numbers in suc- cession from off it, the direction of the spiral being from left to right, from the large towards the small end of the egg. With a little care, almost the whole of the albumen may thus be wound off the egg in spiral strips, the deeper ones enclosing the twisted cha- lazas (see Jig. 46. d). The coagulated albumen presents, in the microscope, a minute but indefinite granular structure. The chalazce (grandines) are two irregularly- twisted cords of albumen, harder than the rest. Fig. 46. Manner in ivhich the chalazce, albumen, §•<■., are deposited round the ovarian ovum of the Fowl. A. Yolk from the upper part of the oviduct soon after it has entered it, showing a thin covering of albumen on the yolk, forming the chalaziferous membrane, and the twisted chalaza? extending from the opposite poles of the yolk. The twisting in these is represented more strongly than it can he seen at this period. li. Sketch of the fully formed chalazse from opposite sides of the yolk, stretched to their full length, and showing the opposite direction of the spiral in each. c. Egg from above the middle of the oviduct; the first layers of albumen deposited round the yolk and chalazse. OVUM. 65 D. Egg from the lower part of the glandular oviduct near the isthmus, when the deposit of albu- men is complete; the spiral arrangement of the albumen made manifest by slight coagulation. attached to the opposite ends or poles of the yolk hy means of a membrane which looks ex- actly like a continuation of the twisted part of these bodies opening or expanded over the surface of the vitelline membrane. These bodies attracted considerable notice from the earlier observers of the structure of the egg, and have had various uses attributed to them ; but, if we may judge from the varieties they are subject to in the fowl and other birds, and their absence in the ova of scaly reptiles (otherwise very similar to those of birds), it would appear that they are only of secondary importance. One of the chalazse is directed towards the larger, and the other to the smaller end of the egg, and the latter usually adheres with some firmness to the inside of the shell-membrane, while that of the large end floats more freely. In this manner the yolk moves more freely at the large than at the small end of the egg. The spiral twist is in opposite direc- tions in the two chalazae ; a circumstance depending on the manner of their production, by the gradual deposit of albumen and the spiral motion of the yolk during its descent in the oviduct. The membrane which pro- ceeds from the chalazae over the surface of the yolk has been called chalaziferous ; and the funnel-shaped dilatation of the chalazte where they join the membrane, has been sup- posed to be the opening of a tube passing through these bodies, and serving as a conduit from the white to the yolk ; but entirely without reason. The chalaziferous membrane and innermost twisted part of the chalazae are, in fact, nothing more than the first- deposited and densest parts of the albumen ; nor is any importance to be attributed to a curved line or fold of the membrane which is often seen stretching over the yolk between the adhering parts of the opposite chalazae. The fact of the upturning of the side of the yolk which bears the cicatricula has already been adverted to, as well as the supposition that Sup]}. the chalazae may be the means of securing this position ; but, although it is well ascer- tained that these bodies control, in various directions, the motions of the yolk, they can- not he the cause of the upturning of the cica- tricula ; as this is secured by the difference of specific gravitj' in the upper and lower parts of the yolk. The true action of the chalazae is to limit the motions of the yolk in the long axis of the egg, and control the rota- tion during a certain time ; but in incubation the relations of the chalazae, wdiite, and yolk are very soon changed ; and, in the progress of these changes, the remains of the denser white are collected at the lower part of the egg. If a fresh egg be turned round on its long axis, the cicatricula will keep its position up- wards for one turn or a little more, and then, by the twisting of the chalazae, the 3olk is carried completely round, and balances itself again with the cicatricula uppermost in its new position. The accessory parts of the egg, now de- scribed, are formed round the yolk or ovarian egg during its descent through the oviduct ; and as they may be regarded as only indirectly' connected with the functions of the true ovu- lum in their relation to embryonic develop- ment, it may be best to complete their history at this place by stating what has been ob- served as to their formation, referring for this to the researches of Purkinje, Coste, and others, which I have confirmed in most parti- culars by the examination of a considerable number of fowls during the process. Formation of the external or accessory parts of the hirers egg. — These parts are produced with much greater rapidity than those of the ovulum. Many fowls lay an egg every twenty- four hours for a part of the season, while others lay only every second day, or two or three days in succession, generally at a later hour on each successive day', and then intermit for a day ; other fowls lay regularly nearly every thirty-six hours. There is probably some difference in the rapidity of the descent of the egg, or at least in the length of time it remains in particular parts of the oviduct, in these various cases ; but in general the whole passage of the egg, from the time of the re- ception of the y olk by the infundibulum to its being laid, occu|)ies about twenty-four hours. If a fowl which is laying only every second day, be killed and opened from seventeen to twenty hours, or if one which is laying daily be opened from three to six hours after the last egg was deposited, one of the ovarian capsules will sometimes be found completely' enveloped by the infundibulum of the oviduct, which is thus in the act of receiving the ovulum or yolk about to be discharged by the cleaving of the capsule along the stigmatic band.* The infun- dibulum is contracted round the neck or pedi- cle of the ovarian capsule, so that the whole is embraced by it with moderate firmness, and the yolk thus usually passes secimely into the * See a later section for an account of the circum- stances which influence the discharge of the ovarian ovula. 66 OVUM. oviduct ; but it occasionally happens that capsules hurst without being so embraced, or that the process is disturbed, and the sub- stance of the yolk falling into the ahiiominal cavity of the fowl either produces serious injury by peritoneal infiammation, or may he gradually removed by ahsor[jtion. The yolk enters the infundibulum, with its long axis corresponding to that of the oviduct, consequently witli the cicatricula on its side, which we shall find to he its position also in the completed egg. The passage of the yolk through the first two-thirds of the length of the oviduct, in which part the albumen is deposited, is very ra[)id, scarcely occupying more than three hours, according to Coste*, before it arrives in the narrow or constricted part of a more liiuitcd extent (isthmus), in which the mem- brane of the shell is formed. About three hours more suffice for this process, and the ovum then enters the dilated portion, which has been called uterus, in which the substance of the shell is deposited and gradually consolidated on its surface. The albumen begins to be deposited round tbe yolk, immediately upon the entrance of the latter into the oviduct; at first in a thin layer, immediately investing the yolk, which subsequently becomes condensed into the chalaziferous membrane, and in two long narrow portions extending before and behind the yolk from its poles, which portions of albumen are at first straight and simple, but afterwards become twisted and form the chalazm. ( See jig, 46, a.) In the next part of the albuminiferous part of the oviduct, in which the glandular struc- ture is most fully developed, the albumen is deposited in much greater quantity round the yolk and chalaza;, not following the form of the latter, and thus soon gives to the whole the oval shape which belongs to the egg; and we then recognise, previous to the formation of the shell or its lining membrane, that the narrower end of the oval is ()laced down- wards, or advances first in the oviduct. During the passage of the egg, and the formation of the albumen, membrane, and shell, a greatly increased determination of blood is observed in the vessels of the se- veral parts of the oviduct. (See jig. 47.) The formation of the accessory parts of the egg appears to proceed nearly in the same manner in the scaly reptiles as in birds. The accompanying figure, borrowed from the article Reptiiia, is illustrative of the main features of the process. The advancing motion of the egg of the fowl is caused by the peristaltic action of the muscu- lar coat of the oviduct, which may be easily seen in any laying fowl opened immediately after death. The egg does not descend, however, in a straight line, but in a spiral direction, corresponding with that of the ridges of glands with which the mucous membrane of the oviduct is beset. Two peculiarities in the structure of the albuminous part of the egg result from this spiral motion — viz., * Hist. g^n. et partic. du D^vel. &c. 1-iig. 47. Descent of the egg in the oviduct of the Tortoise {after Bojanus'). A. Infundibular opening of the oviduct; n,o,p, canal of the oviduct laid open ; s, t, ovum opened, showing the yolk, albumen and shell; B, allantoid bladder ; f, oviduct ; c, v, kidney ; E, ureter ; m, termination of the opposite oviduct. the spiral laminated form of the outer layers of albumen, and the marked tortuosity of the chalazae. It is easy to understand how the spiral form is given to the deposit of the layers of albumen. The cause of the pecu- liar manner in which the chalazae are twisted is not so immediately apparent . it may be explained as follows. As already remarked, the spiral twist is in an opposite direction in the two chalazae ; one end of each of these eords must, therefore, have remained in a state of rest as compared with the other. Either, it may be supposed, the farther ends of the two chalazae extending into the ovi- duct before and behind the descending yolk, remain comparatively at rest, while that body with the albumen forming round it being closely embraced by tbe oviduct has the ro- tary motion impressed upon it ; or, as is more probable, when the chalazae become attached to and involved in the deposited albumen, their outer ends move with it, while the yolk within, to which the inner ends of the chalazae are fixed, does not rotate in the same degree; a circumstance to which it is possible the dis- position of the side on which the cicatricula ' is placed to remain uppermost may in some degree contribute; and thus the yolk not turn- ing so rapidly, or so often as the white, the; chalazae are twisted upon their roots attached ■ to the surface of the yolk.* * It ought to be observed, however, that according to Coste, the jmlk does not at first rotate freely OVUM. 67 Although it can scarcely be doubted that the chalazEe are produced during the de- scent of the egg, while the albumen is being deposited, it is worthy of remark, that the twisted structure of these bodies is usually not to be seen till after the shell has begun to be formed*; but it is very probable that Fig. 48. Position of the egg in the oviduct as it descends. A portion of the oviduct near the lower end opened, taken from a fowl killed three and a half hours -after the last egg was laid. The greater part of the albumen has been deposited, and the egg lias assumed its peculiar form, the small end of the oval advancing first; the cicatricula placed on the side of the yolk. this may depend on their not having pre- viously acquired sufficient opacity or conden- sation to render their tortuous structure ob- vious. Indeed, Von Baer has observed them to make their appearance by increase of their opacity from exposure while under actual observation. It has been ascertained by experimental observation that the membrane of the shell is formed in the narrow part of the oviduct, termed the isthmus, which intervenes between the albuminiferous part and the uterine dila- tation. It consists, no doubt, in the fibrillation of consolidated albumen, or some analogous substance, which must take place with great within the white, and that it is only towards the end of the period of its passing through the oviduct that a liquefaction of the albumen, which then occurs, permits this rotation : but I think it doubtful that the adhesion between the surface of the yolk and deeper albumen is so great as to prevent the degree of rotation above referred to. * Von Baer, Uber Entwick. p. 31. rapidity ; but we are not yet sufficiently ac- quainted with the nature of this process, for the phenomena of the solidification and fi- brillar organisation have not been minutely ex- amined, nor has any difference yet been ascer- tained between the substance secreted in the isthmus, which undergoes the fibrillation with- out calcification, and that of the uterine dila- tation, which seems to have no such tendency, remaining amorphous or cellular, and having very soon a deposit of calcareous matter formed in it. By the time the egg arrives in the uterus, it has acquired its peculiar oval form, the small end pointing downwards in the oviduct. The cause of this form, which is already ap- parent in the white previous to the formation of the shell, is somewhat obscure, on account of the complexity of the mechanical condi- tions influencing the egg in its passage. It may probably depend on the circumstance that the soft mass dilates the oviduct more gradually as it insinuates itself between its coats, in being propelled onwards, while the part of the duct through which it has passed contracts more abruptly and firmly in conse- quence of the stimulus of distension to which it has been subjected. But the variety of forms which occurs in the eggs of different birds and other animals must not be for- gotten, as indicating that the peculiarity of a lesser and greater end is not essential, and may depend on very slight or transient cir- cumstances. Perhaps, the greater density of the albumen, secreted over the end which advances first in the oviduct, may also have some effect in giving this part the smaller volume. It certainly seems remarkable that the ends of the egg should be moulded into so smooth and rounded a surface as that of the membrane and shell by a tubular organ. In some rare instances, however, I have ob- served irregularities of form at the extremities of the egg, inclicating an imperfect contraction of the oviduct during the passage. The egg remains a much longer time (from twelve to eighteen or more hours) in the uterine dilatation of the oviduct during the formation of the shell. The mucous mem- brane of this part differs in structure consi- derably from the rest : it presents over its whole extent large villous-like processes, or short folds, of a flattened form, containing small follicular glands, from which the substance of the shell is secreted. As soon as the egg enters this part of the passage a thickish white fluid is poured out from the membrane, which speedily coagulates on the surface of the membrane lining the shell, and very soon we can perceive with the microscope small heaps or united groups of particles somewhat of a crystalline appearance, but in reality cal- cified blastema studded over the whole surface. These are the calcareous particles of the shell, which are deposited in a delicate matrix of animal tissue of a large cellular structure. The deposit goes on rapidly increasing; at first the shell is soft, it remains friable for a considerable time, and, subsequently, it F 2 G8 OVUM. gradually acquires the peculiar dry hardness which characterises it after the egg is laid.* The view of II. Meckel that the animal basis of the shell is formed by the separation of a layer of the mucous membrane of the ute- rine |)art of the oviduct does not appear to be established. During the time that the shell is forming, the distinction between the softer ami thinner external albumen, and the more dense and deeper part, becomes more obvious, and, at the same time, according to M. Coste, a cer- tain degree of litpiefaction occurs in a layer of albumen immediately surrounding the yolk, which allows the latter body to float more freely within the superincumbent albumen. The egg remains in the uterine dilatation till it is about to be laid. The expulsion of it from this cavity through the narrow part of the tube, leading into the cloaca, requires very strong muscular contraction for its ac- complishment ; and, although the egg always descends in the oviduct, and usually lies in the uterus, with its narrow end downwards, both Purkinje and Von Baer state that they have sometimes seen its position inverted towards the end of the time of its residence there in consequence of the force of the mus- cular contractions of the wall of the oviduct. Ovarian ovum of birds ; vvuhnn ; yolk and its contcnls. — The yolk, yelk, or vitellus (Jaune, Fr. Doiler, Germ.) comsists in the newly laid egg of the external enclosing vitelline membrane, of the yolk substance, a mass of vesicular, cellular, and granular matter of va- rious structure, to which as a whole the membi-ane gives a subglobular form, and on the surface of this mass, below or within the vitelline membrane, and on that side of the yolk which naturally turns uppermost in the complete egg, the cicatricida, or embryo spot, a thin disc of organised cellular structure, in vrhich, under the influence of heat and air, as during ordinary incubation, the embryo, and its accompanying foetal membranes, &c., are first formed. The cicatricida of the laid egg, as has al- ready been remarked, however, has, during its rlescent through the oviduct, undei'gonc some liart of those changes which belong to the lug. 49. Form of the Fowl’s egg and structure of the yolk as exhihited hij a section. A. Sectional view of the fowl’s egg; a, yolk enclo.sed by its vitelline membrane; h, //, inner and outer parts of the albumen ; c, c, chalaza; ; d, two principal layers of the lining membrane of the shell ; e, calcareous shell; f, air-space between the two layers of the shell membrane. B. Outline of the 3'olk; a, cicatricula; h, nucleus of the cicatricida; c, j’olk cavity or latebra, and canal ; d, concentric deposits of j’olk substance or lialones; m, vitelline membrane. I ■1 1 ; I -i' •A, ■i'- fecundated condition, and by which the found- ation is laid of that structure in which the future embryo is more immediately developed ; for it has now lost its germinal vesicle, and from being formed, as at first, of mere granules or simple spherules, it has acquired a true organised cellular structure. It now consi.sts, in fact, of the delicate discoid collection of cells, which has been called hlasloderma. It may be proper, therefore, to consider the mass of the yolk and the germ, in their unfecundated state, while still within the ovarian capsule, * It is to be remarked that the animal basis of the calcareous shell is of quite a different structure from the fibrous lining membrane of the shell ; and the calcareous depo.sit is not to be regarded as taking place in that fibrous membrane. The outer- most layer of the lining membrane adheres very firmlj' to the shell, which may have misled some on this point, who describe the animal basis of the calcareous shell as of the same structure with the fibrous lining membrane. next, after the ovulum has entered the ovi- duct, and, subsequently, when it is laid ; ,?i reserving, however, for a latter part of the article the account of the process by which the change in the cicatricula referred to takes place. 1 In the newly laid egg the yolk forms an ellipsoidal mass, somewhat flattened on the upper or cicatricular surface, and with its long axis corresponding to that of the egg. *. Its largest diameter is about one inch and a quarter, its shortest about an inch ; it floats ^ within the white, capable of a certain degree S of motion, which is controlled, as before ex- ‘T plained, by its own specific gravity, and by the attachment of the chalazae. The yolk substance is not of the same nature throughout, there being a part of a lighter colour in the centre, about one fourth I of the diameter of the whole; from this, a I narrower prolongation extends upwards OVUM. 69 towards the cicatricula, near wliich it again widens and spreads out like a shallow cone. This whiter internal substance constitutes what has been called the central cavity (or latebra) of the yolk : the whole of this inner part has something of the shape of a flask, with a narrowing neck and a wider mouth at the top, which is, as it were, surmounted or closed in by tlie cicatricula. (See fig. 49.) The shape of the yolk, 1 have said, is not that of a regular ellipsoid ; the less density of the upper part, which is towards the cica- tricula, giving rise to a widening of the yolk on that side, as may be seen in /fg. 44, a, which represents a vertical section of an egg boiled while lying on its side. This does not depend simply on the rising of oil globules in greater quantity to the upper side of the yolk, but, as has already been noticed, on the fixed predominance of globules containing oil in the neighbourhood of the cicatricula. Neither is the outer deeper-coloured por- tion of the yolk altogether uniform in structure or appearance ; for it will be seen, both in the raw and boiled egg, but most easily in the latter, that several concentric layers surround the central cavity and canal of the yolk, as well as the funnel-shaped dilatation which lies below the cicatricula. These layers are marked by a slight variation in colour, and are attended by a difference in the minute structure of the corpuscles composing the alternate layers. They probably depend upon the growth of the coloured part of the yolk being more or less rapid at different successive periods. The cicatricula of the newly laid egg is a spot of an opaque yellowish white, easily dis- tinguished by its difference of colour from the re.st of the yolk, about one sixth of an inch in diameter, and lying immediately within the vitelline membrane, in connection at its mar- gins with the most superficial layer of the yolk substance. Examined in a favourable light* it will be found, that in the laid egg, when fecundated, the cicatricula consists of a central clearer and thinner part, and of an external more opaque annular portion. The central part is about one third the diameter of the whole, and seems as if it perforated the remainder of the disc with a circular aperture, something after the manner of the pupil of the iris. There is not, however, any perforation in reality, but only a greater thin- ness and transparency of the central part of the disc. Neither is this central part entirely clear ; for there is placed below its middle a round heap of whitish granules, describetl by Pander as the nucleus cicatriculce (see the figure in section), which gives greater opacity to that part when viewed directly from above. The central part of the cicatricula, already * It may be here mentioned, that by far the best mode of examining the natural appearances of the parts as they lie in the opened egg, is to allow a ray of strong or of direct sunlight to fall upon the part which it is wished to investigate, through an aperture in a screen, which places the rest of the eg’g and the obseiwer in comparative darkness. obvious when the egg is first laid, is the same which, after some hours of incubation, ex- pands, changes its figure, and becoming still Fio. 50, Structure of the cicatricula in a laid Fowl's egg. A. Diagrammatic section of the yolk near the cicatricula, enlarged; a, vitelline membrane; h, cicatricula; c, nucleus; d, canal leading to the cavity ; e, e, large yolk corpuscles of the coloured part: the corpuscles are not represented of their real proportional sizes, but more with a view to show their general difference. B. Enlarged view of the cicatricula, as seen from above on the surface of the yolk in an impregnated egg : the dark central space or transparent area surrounded by an opaque zone and one or ttvo delicate haloes. c. Cicatricula of an unfecundated laid egg : instead of the central transparent area a number of rather irregular transparent spots are seen. more clear, receives the name of transparent area, in the centre of which the embryo be- gins to be formed; while the outer more opaque part retains its greater thickness, and is con- verted afterwards into the vascular and peri- pheral part of the germinal membrane which spreads over the yolk. Round the margin of the cicatricula the deeper-coloured yolk sub- stance is seen even in a perfectly fresh or newly laid egg to be intersected by one or more fine circles of a lighter colour. These seem to be the same which afterwards, expanding and wiilening, constitute the haloes which pre- cede and accompany the extension of the ger- minal membrane over the yolk. These circles are the terminations at the surface of the concentric layers of lighter substance, which, as already mentioned, may be seen surround- ing the central cavity and canal of the yolk (see fig. 49). It seems not improbable that, the difference in the structure of the central and peripheral parts of the cicatricula just stated proceeds from, or is connected with, the peculiar process of fissuring or segmen- tation which follows the disappearance of the germinal vesicle from its central part in the fecundated egg ; but the description of this process belongs to a later section of the present chapter. F 3 OVUM. 70 The cicatricula of the unfecundated egg, such as is laid by fowls secluded from the cock, differs from that now described princi- pally in the absence of the marked dis- tinction between the central clear and the peripheral opaque part. The germinal ve- sicle, which to all appearance remains the same in the ovary till the yolk leaves the ovarian capsule, is now no longer to be seen; and the cicatricula is often marked irregularly throughout, but more especially towards the circumference, with clearer intervals, or small irregular circular or^oval spaces, mingled with the opaque substance of the disc. I have, not, however, had the means in more recent times of making a sufficiently careful exami- nation of the cicatricula in this condition to enable me to state more minutely in what respects it differs from that of the fecundated egg. In the ovarian yolk, while still within its capsule, a white spot corresponding to the cicatricula also exists, and occupies the same place in relation to the yolk cavity and canal. Its structure and appearance, however, are somewhat different from that of the true cica- Fig.5]. Cicatricula, and its contents, in the ovarian egg of the Fowl. A. A square portion of the surface of the ripe ovarian yolk, showing the vitelline disc or cicatricula, wdth the germinal vesicle in the centre, magnified about six diameters. B. Lateral view of the same, to show the con- vexity produced by the thickness of the disc round the germinal vesicle. c. Vertical diagrammatic section of the same ; m, vitelline membrane; d, granular disc ; g, germinal vesicle. D, E, F. Germinal vesicles more highly magnified ; T>, from a yolk of about one tenth of an inch dia- meter, showing scattered globules or germinal spots; E, from a nearly ripe 3'olk, quite clear; r, from another of the same period, exhibiting a turbid or minutelj' granular mass from the action of water. tricula of the egg which has passed through the oviduct ; it is covered by a layer of closely set nucleated cells which lie below the vitel- line membrane ; it contains the germinal vesicle in its centre, and, instead of being thinnest towards the middle, the mass of its granular substance is accumulated in greater quantity in that part round and below the germinal vesicle, and thins gradually off towards the margin. Nevertheless, its much lighter colour than the surrounding part of the yolk makes it always easy to distinguish it. Its margin, however, is not so well marked as that of the true cicatricula ; for the opaque whitish sub- stance seems there gradually to pass into or be continuous with the most superficial layer of cells covering the yolk. To this ovarian rejiresentative of the cicatricula. Von Baer has given the name of stratum proligerum. It is also somewhat smaller than that of the laid egg. It is usually to be found on that part of the yolk which is next the ovary, which, as the yolk hangs wdthin its capsule in the usual attitude of the bird, will be upper- most, and for the most part is situated close to the pedicle of the ovarian capsule. This position is not, however, a constant one ; for sometimes the cicatricula is seen on the sides of the yolk, or towards the stigmatic band of the capsule, but rarely, it would appear, towards the ends or poles of the yolk. The cicatricula may generally be perceived on the surface of the yolk when the outer- most layers of the capsule have been re- moved, and the germinal vesicle can be distin- guished in it shining through the inner layer of the capsule and the vitelline membrane. It is placed close below the nucleated cells which line the latter, and adheres along with them somewhat to its inner surface; so that in gene- ral, it is easiest to remove this disc along with a portion of the vitelline membrane, when it is desired to obtain it for separate and more mi- nute observation by transmitted light. The vitelline membrane being cut round with scis- sors at a short distance from the margin of the disc, the parts are floated off in water or serum, and then may readily be separated with a little careful manipulation. The germinal vesicle, or vesicle of Pur- kinje, may always be seen with the unassisted eye, with a good light, in the centre of the ovarian cicatricula, or proligerous disc, in all ripe ovula, and in most of those which are above a tenth of an inch in diameter. It constitutes there a well-defined shaded cir- cular spot, from to of an inch in diameter. When the proligerous disc alone has been removed “for observation and laid on a flat surface, and viewed somewhat from the side, or when the granules are torn asunder with needles, so as to make a partial section of it without removing or bursting the ger- minal vesicle, it is easy to perceive that the middle part, containing the vesicle, is more elevated than the rest ; and that, although the substance of the disc seems to pass quite smoothly or evenly from the sides over the germinal vesicle, the granules of the disc en- velope the vesicle only slightly, and none cover its middle part : the vesicle, there- fore, is set, as it were, in a depression of the disc, which fits round and overlaps its margins, and a considerable thickness of gra- nular substance is continued in the disc below the vesicle. (See fig. 51, in section). If we select for examination the most ad- vanced yolk of the ovary, which, in a hen laying daily, or almost daily, would probably have OVUM. 71 been discharged from the capsule in a few hours, we may find some difficulty in isolating the vesicle of Purkinje from the granular disc ; for, by this time, the vesicle has become flaccid, weak, and flattened down, and has begun to be softened and dissolved, prepara- tory to its complete disappearance, which generally occurs about the time when the stigma of the capsule opens to allow of the escape of the yolk into the infundibulum which embraces it. But, in all the other yolks down to those of Jq of inch in dia- meter, it is quite easy to break up the granular disc with needle points, and to preserve the vesicle uninjured. We may then free it entirely from adhering granules, and cause it to roll along in the fluid in which it is immersed, or on a plate of glass ; and we may perceive that it is a simple membranous vesicle filled with fluid, and without any very obvious granules or nuclei. In the perfectly fresh state, the contents of the vesicleare almost limpid, exhibiting only a slight turbidity scarcely amounting to a granular deposit, provided it has been placed in a medium which does not change its ap- pearance ; but, if it is allowed to remain a short time in water, and still more if it is im- mersed in fluids which coagulate albumen, its interior speedily assumes a minutely granular aspect. The external wall of the vesicle then separates somewhat from the spherical gra- nular mass within ; and I have sometimes seen (as represented in fig. 51, f) a considerable condensation of the granular mass, so as to leave a large clear space between it and the external vesicle, and give it very much the ap- pearance of the yolk mass in the ova of some small animals within the vitelline membrane. This change seems to be a combined effect of the condensation of the granular mass and the imbibition of fluid by the external vesicle. In the earlier ovula this rounded molecular mass is of proportionately smaller size ; and although it differs very much from the smaller nucleus or macula contained in the germinal vesicle of the ova of many other animals, there can be little doubt that it is derived from this structure, as will appear from what is hereafter said of the progress of its development. When the yolk has passed into the ovi- duct, and, in most instances, probably even sooner, or when it has entered the infundibulum, the germinal vesicle has entirely disappeared. Sometimes it is already gone before the open- ing of the ovarian capsule. The cicatricula then presents an irregularly broken appear- ance in consequence of the vvant of support from the wall of the vesicle, and the dif- fusion of the contents of the vesicle over the surface of the proligerous disc. The solution of the wall of the vesicle is probably a gradual process connected with the state of complete maturation of the ovule. It occurs, as is well known, in the unfecundated as well as in the fecundated egg, and cannot, there- fore, in itself, be dependent on the action of the spermatozoa ; neither is it altogether caused by the mechanical pressure to which the yolk is subjected in issuing from the ovarian capsule, nor by the pressure of the oviduct itself ; for it usually begins, and is sometimes completed before these causes can operate. The difiusion of the germinal substance from the vesicle (which in the fowl must have already received the spermatic influence in the ovary) has the effect thus of mingling with the remainder of the cicatricula, a ma- terial which, it can scarcely be doubted, ex- erts some immediate influence in inducing the change of segmentation and subsequent pro- cess of organisation by which the blastoderm is produced. Mici'osco'pic slructure of the ovum. — The in- vestigation of the microscopic structure of the yolk is attended with considerable difficulty, in consequence both of the variety and the deli- cacy of the organised elements of which it consists. The following parts require our separate attention — viz., 1st. The yellow or external yolk substance ; 2nd, the substance of the cavity and canal ; 3rd, that of the cica- tricula and cumulus ; 4th, the vitelline mem- brane. We shall consider these both in the laid egg and in the ovarian capsule. 1. From the effect of boiling the yolk, every one is familiar with the fact that its yellow substance is coarsely granular ; but the exact nature of the small bodies giving this granular structure has not been equally well understood. The examination of this sub- stance with a microscope of moderate magni- fying power in a newly laid egg, shows that almost all of the deeply coloured part of the yolk consists of spherical corpuscles of con- siderable size, so closely set together that they are mutually compressed ; and thus, when the yolk has been hardened by boil- ing, the substance of the corpuscles being coagulated by heat, they present polyhedral forms ; but when diffused in fluid in the un- boiled state, they are all nearly or quite sphe- rical. The size of these corpuscles varies between and of an inch ; but the greater number of them are more near or „1q. Some have described the yolk cor- puscles as floating in a fluid ; and no doubt in the earlier condition of the yolk, a consi- derable quantity of fluid exists, but in the more advanced condition the amount of mutual com- pression they exert when coagulated is suf- ficient to show that its quantity must be very small indeed. Those who have de- scribed the yolk substance as mainly consist- ing of a fluid holding in suspension a quan- tity of extremely minute granules or molecu- les, together'with some larger corpuscles, have probably been misled, by making an examina- tion of the yolk when not perfectly fresh, and when the larger cormiscles have been in part broken up, and thus resolved into the granular fluid of which they consist. There is no doubt that in birds, and in all the large-yolked animals, the deeply coloured vitelline sub- stance, which, in fact, forms the great mass af these ova, consists almost entirely of the large and usually spherical corpuscles just now noticed. In some animals the form is not F 4 Microsco])ic structure of the ekmcyits of the yolk and ovarian ovum of the Fowl. A. Large granular corpuscles of the yellow part of the vitellus; one of them quite spherical, as they are seen when free ; two others angular from mutual compression, from a boiled yolk. IS. Various corpuscles found on the confines of the yellow yolk and the cavity and canal, showing transition forms to the next set. c. Clear vesicles containing oil globules and de- tached oil globules of various sizes from the cavity and canal. u. h'rom the cicatricula ; a, various-sized granules and globules forming the vitelline disc of the yolk before its discharge from the ovary; h, the organised nucleated cells forming the upper layer of the cicatricula in a laid egg; c, larger cells of the lower la3’er; d, cells of the cicatricula from an egg in its descent through the oviduct in process of formation. A scale with divisions of of an inch is appended. spherical ; as, for example, in the cartilaginous fishes, in which a remarkable variety occurs of a cubical form, and sometimes these mixed with tetrahedral forms, as in the skate.* When free, these corpuscles in the yolk of the bird’s egg roll easily on the surface of a plate of glass as perfectly distinct spherical bo- dies. They present (see Jig. 52, a) a minutely molecular or granular aspect, but with quite a smooth outline or iiiargin to the whole cor- j)uscle. 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 ^o-Jou’ an inch in diameter. ’ See Muller's riiysiulug}', 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 vcsicidar membranous envelope surrounding them. One may sometimes ob- serve a delicate limiting line ; but it has been impossible for me to determine wdiether 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 he 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- |)earance 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 ; anil 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 jn’ismatic shape. In some places also, corres|)onding 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 obseiwation 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 j^olk, I ought to observe that Schwann regarded them as cells in various stages of growth. OVUM, colour, and in the boiled egg by its softer consistence and less granular appearance, i s 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 to ■?oo 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 tJoo 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 Jig. 52, n). 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 73 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.* (Seeyfg. 52, d.) The cells of the upper layer are about ^ J 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 Wo- to -J of an inch in diameter, ot considerable refractino* 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 Beitrage ziu- Entwick. des’ Hlihucheus, &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 pelliicida) 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; so that, in general, on removing apart 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 beyoml an obscure fi- brillar and molecular marking, of such fineness, indeed, as to require a high magnifying power (300 to 000 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 viii). 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 lias 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 i 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 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 opaqne 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 Jj-orJ^ofan 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 cential part of the small ovule, the vesicle ap|)ears 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 growtii, 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 large-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, 'the 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 ; this arises, not so much from the dense structure of the ovary in the undeveloped state, as from the great opa- city ])roduced 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 pi'ocess. 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 vvithin a minute granular mass ; and thh'd, of small germinal vesicles, surrounded with the minutely granular dark yolk substance. Compare with g, in the diagrammatic figure. B and c. Difterent stages of for’raation of the ovi- •sac roimd 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 figui’es it is only shown in 76 OVUM. focus at the margin. e. The ovisac and ovum more advanced ; o, v, ovisac, witli epitlielial lining ; V, minutely granular yolk ; i/, germinal vesicle. F. Part of an ovule of 55 of an inch in diameter highly magnified: v, minutelj' 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. 1 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 ; rf, remains of minutely granular yolk, form- ing tbe vitelline disc round the germinal vesicle ; s, (/, large corpuscles of the yolk ; v, m, outer layer of the cells of the same, on which the vitelline mem- brane is aftei'wards formed. been loolicJ upon as the primitive or first- formed structures connected with the origin of tlic ova, tlie germinal vesicles subsequently making their appearance within them. We shall return to this [joint hereafter in con- nection with the history of the mammiferous ovum. My own observations agree with those of Uarry, as I have sometimes observed very small germ-vesicles or cells in the ova- rian stroma without any follicular covering. But it must be atlmitted, 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- natlva. 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 of an inch in diameter. * At a somewhat later period, the number of maculm (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 wdiich tbe primitive yolk granules are deposited. This will be made more apparent in our description of the formation of the ova of Batrachia. there begin to be formed within the ovisac a seU 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 [jarts 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 coni[)lex 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 5 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 inammi- ferous ovum. If this view is correct, we may expect to finil 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 pavtiellel Ftirdiung bestimniten Eier der Vogel, &c., in Sie-1 bold and Kdlliker’s Zeitseh. fUr Wissensehaft. Zool.^ vol. iii. p. 420, 1852. OVUM. 77 in the niarnmiferous 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 niendirane, to which he thinks himself warranted in giving the name of zona pellucida, disappears, and already in ova above i\j of an inch there is no trace of iNeft. The observations of H. Meckel on this sub- ject appear to be both novel and important ; but he has not been equally successful in the theoretical deductions made from them. In the commencement of the paper before referred to, he thus announces his view of the morphology of the bird’s egg : “ For a right and consistent nomenclature and defi- nition, we must designate the corresponding parts according to their analogy with those of the human body. I believe, therefore, that that alone ought to be regarded as the true egg which exists in Man, Mammalia, Naked Amphibia, and Osseous Fishes; and that in the remaining Vertebrata the ovum consists only of the so-called vesicle of Purkinje, and that all the other parts are accessory, super- imposed, and unessential. In particular, that the yellow yolk of the bird and scaly reptile is analogous to the corpus luteum of the human ovary, the albumen ovi to the uterine secretion, and the calcareous shell to the de- cidual mucous membrane of the uterus.” Von Baer, at p. .32. of his Epistola, uses the fol- lowing words, which have been much contro- verted by some of those coming after him, but which show that he was aware of the difterence in the relation of parts in the birds and mammiferous ovum ; “ Vesicula ergo Graafiana cum ad ovarium generatimque ad corpus maternum respiciamus, ovum sane est Mammalium, sed evolutionem quod attinet, vehementer discrepat a reliquorum ovo ani- malium,” &c. And again, “ In mammalibus vesicula innata vitelhim magis excultum cou- tinet, et ratione ad fetum geniturum habita verum sese probat ovum. Ovum fetale did potest in ovo materno. Mammalia ergo ha- bent ovum in ovo ; aut, si hac dicendi formula uti licet, ovum in secunda potentia.” Both in the Epistola, and the Commentary upon it. Von Baer insists strongly on the analogy be- tween the cellular substance of the Graafian follicle and the yellow yolk ; and he seems to have erred chiefly in limiting his comparison of the mammiferous ovum (within the zona) to the vesicle of Purkinje of the bird’s egg. If, therefore, we modify Von Baer’s view so much as to regard the vesicle of Purkinje along with the granular cicatricula of the bird’s egg, as corresponding to the whole of the mammiferous ovum, and the granular cells (tunica granulosa, &c.) of the Graafian vesicle as corresponding to the yellow yolk (the zona pellucida having disappeared in the bird’s egg), we shall establish a more correct relation of the parts than that suggested by H. Meckel. I am not aware of any animal in which the germinal vesicle alone, without some yolk substance and an external inclosing membrane (zona, or vitelline membrane) forms the entire ovum. I will now state the result of my owm ob- servations on this subject, by which 1 con- ceive is proved the correctness of H. Meckel’s view, that in birds there is a primitive ovum, enclosed within a zona, distinct from tlie large mass of cellular yolk, which is formed at a later period. As soon as the membranous wall of the ovisac or ovarian follicle has become distinct in the ovary of the fowl, we can perceive at the same time a layer of larger cells lining it which form a clearer ring round the opaque ovule. The ovule itself consists then merely of the germinal vesicle and a small quantity of the primitive yolk substance. Tlie latter becomes opaque at so early a period that it in general hides completely the germinal v e- sicle. It seems to arise by the deposit of very fine granules, probably of an oily nature, in a dense albuminous fluid or blastema which col- lects round the germinal vesicle very soon after the latter is invested by the ovarian fol- licle. In follicles of of an inch in dia- meter the primitive ovule, the membrane of the enclosing follicle, and between them the layer of larger clearer cells, are all perceived with facility. There is not yet, however, any investment of the ovule com[)arable either to a zona pellucida or vitelline membrane. In ovarian follicles of or of an inch in diameter, a farther progress is to be per- ceived. On bursting any such follicle with fine needle points, tlie ovum is ruptured, and the germinal vesicle usually first escapes along with the more fluid internal part of the yolk, in which it is freely suspended. This vesicle is about of an inch in diameter, presenting externally a smooth, thin and de- licate vesicular membrane of a spherical form, of which the double outline is just discernible with a magnifying power of 300 diameters. The vesicle is partly filled with fluid and partly with a finely granular spherical mass of no great opacity, which corresponds to the macula germinativa. In most instances this mass occupies about two thirds of the diameter of the vesicle. The yolk substance, which has scarcely altered from its primitive opaque finely granular condition, now con- sists of a more fluid internal part containing fewer granules, and in which the germinal vesicle floats, and of a more consistent e.x- ternal part. In the latter a manifest change has occurred in this respect, that towards the outer surface there is seirarated a much clearer ring of substance contrasting strongly with the more opaque part. This may with correctness, it is true, be described as a mem- brane, as 11. Meckel has done in comparing it with and giving it the designation of the zona pellucida. But the very remarkable structure, which the author now mentioned has had the merit of first pointing out, is one deserving of the greatest attention. It has appeared to me to be gradually formed in ovula of 78 OVUM. about or -gL of an inch in ciiameter, by the clearing ami partial consoliJation of the outermost part of the albuminous basis or blastema in which the granules of the [iri- mitive yolk substance are deposited. It is at first comparatively thin : it is most ap- parent by its greater clearness and consistence in ovules of or of an inch in diameter, in none of which have I ever failed to observe it. In those of it becomes broader, but less clear and somewhat softer in its consistence, and is uneven and as if softening away or breaking up on the e.Kternal edge ; and in ovules of of an incli it has in general dis- appeared. At no period have I observed it to assume the glassy transparency, nor has it the distinct outline and membranous appear- ance represented by 11. Meckel; but it seemed rather like a portion of the albuminous basis of the yolk substance, nearly but not quite de[)rived of the granules, which are thickly deposited in the rest. Wlule these differences are stated, how- ever, it appears to me warrantable to coincide in so far with the view of II. Meckel as to regard this structure as a tem|)orary repre- sentation in the fowl’s egg of the zona pel- lucida, which in the mainmiferous ovum assumes greater consistence, passes into the membranous form, and constitutes the only ovarium covering of the ovule. In ovules of 3*0 to ^’o of an inch in dia- meter, the layer of nucleated cells placed be- tween the primitive ovule and the membrane of the follicle, and which may be looked upon cither as a cellular lining of the follicle or a peculiar investment of the ovule, has be- come more distinct and consistent, and the cells of the outermost layer have assumed the form of short compressed prisms. They have finely granular contents and clear nuclei, with one or sometimes two nucleoli, like the cells of the tunica granulosa of the mammalian follicle. It appears that these cells come afterwards to form the external part of the yolk of the bird’s ovum, the cel- lular part of the yolk being formed within them, and the vitelline membrane being pro- duced on their outer surface. The bird’s ovule, it is well known, usually fills completely the ovarian follicle ; but in several instances I have observed, from im- bibition of water or some other cause, the ovule to occupy not more than half the dia- meter of the follicle, the remainder being filled with a clear fluid ; and in these in- stances the prismatic layer of cells adhered closely to the surface of the zona and primi- tive granular yolk. In ovules of from to of an inch the formation of the vitelline membrane appears to commence. The external nucleated cell covering has increased in quantity, and ad- heres more closely to the granular yolk, with which it generally comes away when the follicle is opened. The external edge of the layer of prismatic cells, the length of which is considerably increased, is now surrounded by a narrow |rellucid space enclosed by a double line, presenting the appearance as if a small part of the bases of these cells had been fused together in a homogenous film. This is the commencement of the formation of tlie true vitelline membrane, which in the latest |)eriod of ovarian growth of the ovum becomes nearly quite structureless, but which throughout the greater part of the process retains somewhat of the liexagonal marking from the close adhesion of the cells by the amalgamation of a part of which the mem- brane has been produced. In follicles of about of an inch or larger the true cellular elements of the yolk have begun to be formed. The manner in which these originate I have not as yet had the means of determining with precision. They appear, as H. Meckel has suggested, to be produced as a secretion from the interior of the ovarian follicle ; but they are more im- mediately formed within the layer of pris- matic cells which envelope the whole ovule. Nor have I been able to determine their precise relation to the zona and primitive fine granular yolk. When the zona has dis- appeared, as is usually the case in ovules of of an inch, the cellular elements of the yolk seem to begin to mingle with the finely granular substance. At first, cells and larger oil globules, similar to those of the yolk cavity, are itroduced. So long as these alone exist, the yolks have a dull milky-white as- pect. Later, or in those of | of an inch, or even somewhat smaller, the yellow tinge appears, and this very soon becomes more decided, at the same time that the peculiar large granular corpuscles or cells are formed in which the vitelline colouring matter prin- cipally resides. These corpuscles are pro- duced in successive layers within the layer of prismatic cells of the external tunic ; and it is probable that there is some periodical variation in the rapidity of their formation from the alternation of concentric layers of deep yellow corpuscles with those of a lighter colour which may be observed in the section of a boiled yolk. The corpuscles of the yellow yolk are not, however, formed in equal quantity in every part : indeed they are quite cieficient at that side on which the remains of the primitive granular yolk with the im- bedded germinal vesicle are situated. With regard to the germinal vesicle, it is to be observed that it is at first quite free in the more fluid internal part of the primitive yolk ; in the next stage, before the formation of the cellular yolk, the germinal vesicle comes to be imbedded in the more consistent external part of the primitive granular yolk ; and it is, no doubt, chiefly the remains of this which form the germinal or vitelline disc ; but further observations are still required to de- termine the precise manner in which this ar- rangement of the primitive yolk in the discoid shape takes place. It appears, further, that in the formation of the elements of the more advanced yolk, the earliest produced, or innermost, remain the softest ; the latest formed, or outermost, acquire the greatest consistence. The ex- ternal layer of prismatic cells next the vitel- OVUM. 79 line membrane passes with it completely roimcl the whole yolk ami over the vitelline disc ; the next layer, less prismatic and more rounded in their form, but still distinctly nucleated cells, covers the whole sm’face of the yolk, with the exception of the part oc- cupied by the vitelline disc, with the margin of which this layer is continuous. The next layers passing inwards consist of granular corpuscles, which do not in general present the appearance of nucleated cells.* In conclusion, therefore, the ovarian ovum of the bird being formed in an ovarian capsule, is at first very similar to the Graafian vesicle of the mammalia, and differs chiefly in the earliest stages from the mammiferous ovum in the proportionally large size of the germinal vesicle, and in the absence from this vesicle of the more distinct and persistent nucleus which exists in animals having the smaller yolk. This germinal vesicle may be looked upon as the fundamental part of the ovum in both kinds of animals. Along with it there exists, from a very early period in birds, a gra- nular opaque yolk substance. This substance by itself constitutes the whole yolk of mam- malia; but in birds it probably remains as a part, if not the whole, of the proligerous disc (afterwards cicatricula). The mammiferous ovum is closely surrounded at an early period with a dense transparent membrane (the zona pellucida) formed by a condensation of the outermost layer of the albuminous part of the yolk ; and a similar envelope, but less dense, exists in the earlier stages of formation of the fowl’s egg, surrounding the finely granular primitive yolk substance along with the ger- minal vesicle. In both birds and mammalia the ovarian follicle, besides being lined wuth a layer of epithelial cells, secretes, or has formed immediately within it, a quantity of nucleated granular cells more loosely united together, known in mammalia by the some- * While the above was passing through the press, I received the 27th and 28th pa'i-ts of E. Wagner’s Handworterbuch der Physiologie, containing the Article “ Zeugung,” by Professor Leuckart of Giessen. I regret that I have not previously had the advantage of perusing the very luminous and comprehensive sketch, by that author, of the struc- ture and morphology of the ovum of different ani- mals. As, however, Professor Leuckart has stated that his observations do not confirm the statements of H. Meckel in regard to the zona pellucida of the bird’s ovule, I have thought it right, notwithstand- ing the unfavourable period of the year (October), to repe.at carefully my examination of this matter ; and 1 have here lo state that, in the common fowl and thrush, the description given above has received the fullest confirmation. While, therefore, I am inclined to differ, as above stated, from the views of H. Meckel as to the morphological analogy of parts of the ovum in different animals, I must admit the existence, at a certain stage, of the very pecu- liar structure pointed out by him, as corresponding with the zona pellucida, with the differences as to details which I have there mentioned. The primi- tive ovule of the bird therefore consists of the ger- minal vesicle, granular yolk, and this so-called zona ; and the cellular substance of the bird’s yolk, is the product of secretion, or is a modification of epithelial formation frotn the interior of the ovarian follicle. what inappropriate names of tunica granulosa and substantia granulosa of the ovarian fol- licle. But in birds, although this substance is at first somewhat similar in structure and rela- tions, cells afterwards increase within it in very large quantity, and acquire a peculiar structure and colour, constituting the yellow part of the yolk substance. The outer cover- ing of the yolk, or vitelline membrane, is only produced when the ovule has attained con- siderable advancement, by a new deposit upon the external surface, or by the condensation of a part of the external layer of these cells, which covers the whole yolk, together with the cicatricula. The germinal vesicle is fixed in the bird’s yolk, towards the surface, in the proligerous disc. In the mammiferous ovum the germinal vesicle is, for the most part, near the surface of the yolk substance, but not so far as is known in a determinate situa- tion, and the whole ovum in its zona pellucida is fixed in the tunica granulosa towards that part of the follicle which is next the surface of the ovary. The germinal vesicle bursts or is dissolved in both. In mammalia it is probably diffused through or over the whole granular yolk : in birds it probably overspreads only the proli- gerous disc. The whole yolk is segmented in mammalia, while in birds this process is con- fined to the proligerous disc, out of which the blastoderma is produced. The full description now given of the struc- ture of the bird’s egg will enable me to treat comparatively briefly of that of other animals. In regard to most of them, indeed, it will scarcely be necessary to do more than to no- tice their most important peculiarities. Before leaving the ova of the first group, it may be noticed on the authority of Leuckart*, ' that in the scaly reptiles there is not the same difference between an external coloured yolk and the lighter cavity as in birds, but that the whole yolk substance is of a paler colour, and of a more clear and uniform appearance. Still from a preponderance of oily matter in the vicinity of the cicatricula, there is the same tendency to that part of the ovum floating uppermost. The germinal vesicle in the ova- rian ovum of these animals presents at an early period a very subdivided condition of the macula ; and it is placed in a granular disc, which does not appear to differ essen- tially from that of birds. The vitelline mem- brane is equally structureless. Leuckart has traced the development of the ovum in La- certa crocea and Coluber laevis, and has ascer- tained that in them, as in birds, the primitive yolk substance is destitute of cellular ele- ments, and has at first no special covering. The true or external vitelline membrane is probably formed, precisely as in birds, on the exterior of the outermost layer of the cellular part of the yolk. In the cartilaginous fishes there is a greater departure from the type of structure now de- scribed. The external vitelline membrane is of Art. Zeugung. 80 OVUM. great delicacy, and is perceived only with difli- culty. The yolk substance is in great part com- posed of peculiar angular corpuscles, sometimes flat and tabular, at other times cubical, octahe- dral, and of other forms. It has been stated by Leydig* that in the plagiostomatous fishes there is no vitelline disc or cicatricula ; but this does not agree with my observations in the common skate fish, in the ova of which I have always observed a vei'y distinct flat disc about three-eighths of an inch in diameter, of a lighter colour than the surrounding part of the volk, and situated on the surface which naturally floats uppermost. The germinal vesicle, which is larger than that of birds, sometimes of an inch in diameter, is ex- tremely delicate and very easily ruptured. Its nucleus or macula is originally single, but becomes afterwards subdivided or multiple and dittiiscd. The ova of the cephalopoda, which may, according to most embryologists, be included in this group, are of considerable size. They possess a germinal disc, and the segmentation of the yolk is partial or is confined to that disc, as in the animals previously mentioned, f The large yolk cor[)uscles are spherical masses of united oil granules, and like the most of those of the bird’s egg without any true enclosing vesicle. The germinal vesicle is of considerable size, and has subdivided inacultE. The whole are enveloped by a fine structureless vitelline membrane. Iii the course of the formation of the ovum, the ex- ternal part of it undergoes a remarkable ebange in being folded inwards in numerous deep grooves, which almost reach the centre of the yolk. This folded structure is in the smaller species again effaced before the ova reach maturity, but in the larger species it appears to remain, and to be the cause of a peculiar reticulated marking over the surface of the ova. In regard to other classes of the inverte- brate animals of which the ova may appear to belong to this group, 1 shall have occasion hereafter to state some additional facts, in explanation of the manner in which in some of them the granular and cellular elements of the yolk are occasionally combined. From the foregoing considerations, then, it appears that in ova of the first group as dis- tinguished in this treatise, the germinal vesicle is at once the first formed and the fundamental part of die ovum around which the rest of the parts are deposited. It alone, therefore, is strictly to be regarded as a simple or primary cell. It may aptly be called the Germ-celL In birds its nucleus or macula is originally simple, but at a very early period it undergoes subdivision into nucleoli or maculae, so numerous and minute * Beitrage zur Blikroskop. Anat. der Rochen iind Ilaien, p. 87., a work which I quote only from Leuckart. f We owe this interesting discovery to Kolliker. See his work on the Development of the Cephalo- poda. Zurich, 1844. as at last scarcely to be recognisable, and thus' the germinal vesicle loses in such animals somewhat the characteristic cellular struc- ture which it presents in many others. Next, by aggregation of the primitive yolk substance round the germ-cell, and by the gradual con- solidation of a clear film on the outermost part of the albuminous matrix of this sub- stance into the form of an enclosing vesicle, there is protluced the 2}ninilive ovum, a secon- dary cell, in which the zona pellucida consti- tutes the cell wall, the oil granules and albu- minous fluid of the yolk substance the con- tents, and of which the germinal vesicle is now the nucleus. And lastly, if it is consi- dereil desirable to extend the application of the term cell also to the mature state of the ovarian egg of the bird, we may perhaps still regard that organism as a tertiary cell (in the ascending series) formed by the superposition of new parts, some of which are themselves cellular in their origin, round the primitive ovum, the whole being at last enclosed and moulded in the vesicular form by the external vitelline membrane ; a peculiarity of this for- mation being that in the meantime the wall of the secondary cell or primitive ovum has disappeared. But, notwithstanding the sphe- rical form, the isolated position, and the simple structure of the parts which compose the completed ovarian ovum of birds, doubts may fairly be entertained as to the propriety of bringing such complex organisms under the designation of cell as now generally em- ployed. 5) 5. More detailed description of ova be- longing to the second group, or with small granular yolk and complete segmentation. If the foregoing views are correct, it appears that, while the ova of birds and other animals of the first group contain within the vitelline membrane the whole product of formation which belongs to the ovarian capsule, the ova of mammalia and animals of the second group comprehend only those parts of the contents of the Graafian follicle which are formed within it at the earliest period — viz., the germinal vesicle and the primitive yolk substance with its limiting zona. In the Graafian follicle of mammalia, there is likewise produced a large proportional quantity of cellular elements and albuminous fluid, the tunica and substantia granulosa, &c., in a part of which (cumulus proligerus), the ovum comes to be imbedded in the progress of their formation ; and these snperadded contents of the Graafian follicle escape along with the ovum when it leaves the ovary, but do not aiqiarently maintain any long or constant connection with it. In the ova of those invertebrate animals which belong to this group, the conditions of formation do not admit of their comparison with those of mammalia ; but they agree with them in so far that the first germ-cell is en- closed by a finely granular yolk, and that the vesicular envelope of the ovum generally cor- responds to the zona formed by consolidation on the surface of the primitive yolk. OVUM. Ovum of Mammalia and of the Human Species. — -There is a remarkable uniformity in the size, structure, and relations of the ovarian ovum in the whole class of Mammalia, with the exception of the families of Marsu- piata and Monotreraata ; in the last of which especially there is an approach to the oviparous type. We shall first consider the more com- mon form of the mammiferous ovum. Of this the most marked characteristics are, as has already been stated, the very small size in proportion to the ovarian follicle, the finely granular yolk-substance, and the dense, clear, and firm external covering or zona pellucida. The Graafian follicles, or ovarian vesicles, in which the ova are situated, attain, when mature, a size of from to ^ or even i an inch, varying in size in some measure with, but not in exact proportion to, the stature of Fig. [81] the animals. In the human ovary these fol- licles are firm spheroidal sacs, which attain when mature an average size of about i of an inch. In the ovaries of women, during the child-bearing period, a number of smaller folli- cles lie throughout the greater part of the substance of the ovary ; the more developed follicles being usually placed towards the free surface, but at some little distance from it. As they enlarge and approach maturity, the ova- rian substance appears to give way to them, or to become gradually thinner between the follicles and the outer surface of the ovary, so as at last to leave almost nothing but the covering membranes of the ovary at the most projecting part. Even when of their full size, however, the Graafian follicles of the human subject and of most animals do not project much beyond the general surface of the ovary; 54*. Mammiferous Oman. A. (From Coste.) Human ovary enlarged four diameters, partiallv dissected at oo o, to show the (iraahan follicles in the ovarian stroma : one of these, more advanced, has had its double tunic o v cut into and reflected ; the granular membrane 7n g has also been partially opened, showing the thickened portion or granular disc dp, in which the ovum is imbedded near the most projecting part. At 0 V , another Graafian follicle has been burst, and the ovum in its granular disc is seen expelled from it. B. Transverse section of the human ovary, to show the general arrangement of the developed Graafaan follicles towards the surfirce; twice the natural size. c. Diagrammatic representation on an enlarged scale, in section, of two Graafian follicles, in dif- ferent stages of advancement in the ovary of a mammifer. p, peritoneal covering of the ovary ; St, ovarian stroma ; o v, the two layers of the ovisac ; m g, membrana granulosa, near which is the discus granulosus, with the ovum imbedded. OVUM. [82] but in some animals, in which the vesicles are proportionately more expantled, 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 ap()earance 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. bo*. ‘if/*’’’ Ovarian ovum of the Dog. (F?-07ti Bischo ff.') a, magnified representation of the ovarian ovum of the dog, nearly mature, situated in tlie discus pi'oligerus and part of the cells of the granular membrane; h, 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 ; c, 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 yolk substance ; in the latter the germinal vesicle is obscured by the opacity of the substance sur- rounding it. f, 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 memhrana granulosa, from the opaque granular appearance of the cells composing it. Tliese cells form a com- plete vesicular lining of the follicle; but throughout the greater part they cohere with otdy a moderate degree of firmness, so that the membrane readily tears when the follicle is opened. The niinute 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 maybe detected in the undissected fol- licle through its coats and the ovarian cover- ings. The cells of the membrana granulosa are in general about 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 avvay from the rest by the [tressure 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 th.e retinacida of Barry. The size of the mannniferous ovum itself is much more uniform among the different families of Mammalia than that of the Graafian follicle. OVUM. Fig. 36*. Ovum of the Rahhlt 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 -f to 2^0 or 3^0". 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 j-io’ cat rabbit rat mouse P'g ^uo’ cow 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 to or from 1 to 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, Lipsice, 1827. [83] parent. It has recently been stated by Ilemak*, 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 J?g. 53 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 tw'o 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 ditferent destination in connection with embryonic development, in- asmuch as, though formed iu 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 inammiferous ovum, I have adopted the view' first advocated by Coste]-, and by Thomas Wharton Jones J ; and more fully brouglit 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 mammiferousovum is invariably enclosed from an early period of its formation in the ovary, this term is used synonymously w'ith that of vitelline membrane, and as applied to * Muller's Archiv. &c. for 1854, p. 252. t Recherches sur la GenCTation des Mammiftres, 4to. Paris, 1834, fig. 2. ; and Embiyogenie Com- paree, tom. i. p. 200, Paris, 1837. J In a paper read to the Royal Society of London in 1835 ; printed in the London Medical Gazette for 1838, p. 680. § Entwickehmgsgeschichte des Kanincheneies, Braunschweig, 4to. 1842 ; and Entwickelungsg. des Hundeies, Braunschw'eig, 4to. 1846. OVUM. [841 the only covering with which the ovarian ovum is provided at the time of its leaving the Graa- fian vesicle, exce|)ting 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 ; anil 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 envelo[>e which he terms the cortical membrane, and of another situated within it. It is well known that when the mammi- ferous ovum has been fecunilated, 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 pelhicida 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 |)lace independently of fecundation or foetal ilevelopment, it is necessary for me to make some remarks in this place on the relations of the zona pelhicida 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 o[)inions in regard to it in the progress of their researches. Von Baer, the correctness of whose general views on the [ihenomena of development we have occasion to admire in almost every part of the subject of which he has treated, was at first of o|)inion 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- lopmentf , published eight years later than the Epistola and Commentary, he states his convic- tion from his observations, that in some mani- miferoiis animals at least, such as the jiig 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. f Beobachtumr. und Reflexion, liber Entwicke- lungsgesch. See., Kbiiigsberg, 1887, 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 w'hich 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 |)ellucida. 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 ([uite assured that a new .structure had made its appearance in considerable thickness on the surface of the zona, yet he at first sup- jiosed 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 mara- 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 pelhicida 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 ovum ; and this new deposit he now regarded as “ tlie 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 pelhicida, 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. Bischoft' also had not been aware from his earliest observations that any new deposit occurred rounil 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 dev Entwick. &c. des Mensclieu, Berlin, 1835, pp. 38, 39. t On the Eir-st Ch.anges in the Ova of theMam- mifera, in consequence of Impregnation, and on the Mode of Origin of the Chorion, in Bhil. Trans. 1837, part. ii. p. 339. J See Phil. Trans, for 1839, p. 31G, 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. Ova of the Rabbit from the Fallopian tube three days after impregnation. A, shows on a dai'k ground one of these ova, of which B is an explanatorj' outline, y, s, are the yolk segments of which there w'ere eiglit ; 2, 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 down 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 iniluced to adopt the opinion that a nevv deposit does really occur on the surface of the ovum in both of these animals. I repeatedly ob- served the large gelatinous or film 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 s[)routing 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 Fig. 58*. 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 represeuti d too light in the figure.) B. Explanatory outline of the same ; y, s, jmlk segments; 2, zona pellucida; a, laj'er of albumen, from which in connection with 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-miicous 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 tlie first two or three days of the resilience 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 fig. 55. u.) It is quite easy, tberefore, 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 [G .3] OVUM. [80] 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 j)roofs of a new deposit having taken place. This deposit, no doubt, becomes very completely incorporated witli 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 de[)Osit. These villi, which, as I have said, form a most characteristic feature of tlie 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.]' They are developed from the external surface, anil 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 ftetal 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,!!! whichgranules, or molecules and globules of various sizes, from the most minute up to about or 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 wlien 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 Meerschweiuolieiis, 4to. Giessen, 1852. t Barry and Bischoff. Ovarian ovum, of the Rabbit. (^From Coste.) a, ovarian ovum extracted from a nearly ripe Graafian f’olliide, and freed from the adliereiit 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 ' adhei'ing 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 t is punctured, the yolk-substance flows freely out, while in others, and this is the case in ; the human ovum, the yolk-substance holds 1 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-i trary is readily detached from it ; and in somel instances, in the entire unimpregnated ovum, a j space is seen between the yolk-substance andl the zona, formed apparently by the imbibition 1 of water between them. This separation be-j tween the yolk -substance and zona appears] to be, at a later period, a constant and |)ro-j bably important change in connection witlij fecundation and development. The granules of the yolk-substance are ge-1 nerally rather more densely set together andj OVUM. more firmly united towards the externalsurface. This circumstance has given rise to the belief amoni; some observers in the existence ot an additional delicate membrane enclosing the yolk-mass ; but the most attentive observa- 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 filth 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 n)anifest 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 in diameter, such as that of the rabbit, the diameter of the macula is about one-fourth of that of the vesicle, or • 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 anti 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- [87] mined by observation in the Mammalia, nor has any one as yet succeeded in observing a canal or pore leading from the surface of the yolk-substance towards the germinal vesicle in the mammiferous ovum. Fig. 60*. Ovum of the Fahlit from the Fallopian tube with spermatozoa. Tlie accompanr-ing 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 dift'erent 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 la.st is not suffi- ciently clearlj" represented in the figure. In the situation now described the germinal ve.sicle, though not by any means firmly fixed, is yet sufficiently embraced by the yolk- substance to prevent it from changing [>lace when tlie 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 [88] OVUM. Fig. 61 *. Tliis ovum is ropresenteil in ordei- to show the peculiar pyriform shape of the macula iu the ger- minal vesicle, to the wall of which the macula appears to be attached. This ovum was taken from a Graafian follicle of .jL" iu diameter. The following are the dimensions of its several parts which are magnified 250 diameters in the figure. The o\-um across the exterior of the zona -pj"; the vitellus the germinal vesicle ■, the ma- cula ; thickness of the zona The ovum is surrounded hy the thick l.aj’er of cells which form the granular disc, lip. 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 disappears in Mammalia previous to the es- cape of the ovum fi'om the Graafian follicle ; but in this class of animals the phenomena attending the disap|)earance have not yet been fully investigated. There are some grounds for believing that immediately pre- vious to the bursting of the vesicle there may be changes of the macula and other contents of the vesicle of a corres[)onding nature with those which have been more clearly observed in Batrachia and Fishes. Dr. Martin Barry seems to have observed something of this kiTid, and M. Coste has figured, but not so far as 1 am aware described, the development of cells in the germinal vesicle of a ripe ovarian human ovum.* * * § K. Wagner states, that occasionally a double macula may be seen in the germinal vesicle. f 1 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. if This had been previously noticed by 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- mifferes ; Homme.” Pi. I. Fig. G. t See Prodromus Hist. Generationis, Fig. xxxi. j Muller’s Archiv. Jahrsbericht, p. 1C9. § Muller’s Archiv. 18-12, p. 8G. 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 ami 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; ami 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 jtart of the tunica granu- losa with a low magnifying lens, or even sometimes with the naked eye. In the ovary of the dog the ovum may sometimes be seen w'ithout any dissection towards the most 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 may be opened with very finely-pointed and sharp scissors, and the surface then s|)read out and examined carefully with a low magnifying power under a good elumination, but this must not be done under water ; or another plan may be followed according to the re- commendation of Martin Barry, founded on a suggestion thrown out by Cruickshank, as follows : The F’allopian tubes being divided into several portions, the contents of each portion are to be separately pressed out by passing a blunt instrument firndy along the outside of the tube, and, being placed on suit- able plates of glass, are to be subjected to the necessary examination. The latter method is [larticularly 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 * Vol. iv. p. 973. Cycloposd. of Anat. and Physiol. j- See Von Baer’s Commentary on his Epistola, in Breschet’s Repertoire, 1828, p. 38 X See Barry’s Second Series of Researches, &c., Phil. Trans. 1839, p. 30G. OVUM. [89] avoid injuring the ova, and that the examina- tion must be made at first in the dry state, Orighi and Formation of the Mammiferoiis 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. Cams 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 age 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 I are distinctly formed, even at an earlier period. I By the age of ten or eleven years a number of I the vesicles are found to be approaching ma- 1 turity, and almost all have left their earliest I condition. Both Barry and Bischoff, how- ; ever, are of opinion that new sets of Graafian 1 follicles and ova may continue to arise within I the ovaries during the whole child-bearing j period of the human female; and there can be I little doubt that this takes place in most of the 1 lower animals. I Bischoff describes the Graafian follicles as ! taking their origin from minute heaps of I granules in the ovarian stroma; but he has ! not been able to confirm the statement of i Valentin that the earliest follicles proceed 1 from primitive gland tubes stretching from I the attached border towards the surface of d the ovary. f In various animals the follicles i and ova begin to be formed at an earlier .i period than in the human female : according I I to Bischoff, they arise very early both in the I j cow and pig. 1 When the primary follicle can be perceived, 1 it consists of a small vesicle scarcely more than I ’n diameter. To this primary vesicle Martin 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 Entwickelimgsgeschiclite, 1835, p. 389. ; and Muller’s Archiv for 1838, p. 529. Fig. 62 *. Development of the Ovarian ovum of Mammalia. i^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, w hich have somewhat the appearance of those of epithelium, and which thus give rise to a clear space between OVUM. [90] the membrane or wall of the follicle, ami 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. G3 stage. The follicle here represented was about in diameter: in the figure it is shown as it appears under 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 ligures 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. + Article Zeugung in Wagner’s Ilandvrorterbuch der Physiologie, 1853. which cannot be said to have existed from the first, conies to be apparent outside the opaque granular substance of the yolk, and close to the ejiithelial 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 con.sists 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 to 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 Gi'aa- 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 Mar.'^iipialia, in which, from the remarkable deviation from the more common mode of gestation, it has been siqiposed that the ovum might present some peculiarities, it does not appear, from the observations of Professor (iwen, 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^io^', and the germinal vesicle was only which is proportionally small ; so that it cannot be held that in this animal there was apparent any approach to the oviparous tvpe. In the Monotremata, however, the ovum is OVUM. 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 ditferent 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 com|)aratively large size, being about 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, wliich 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 some of them about in diameter : they contained a large quantity of granular globules similar to the yolk cor[)uscles 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 Cyclopajdia, and his Memoirs in the Philos. Trans, for 1832 and 183.5. See in particular figures 191, 192, and 194 of the article Monotremata, Cylopaad. of Anat. vol. iii. p. 393, et seq. f Article Zeugung, p. 783. [91] 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, and 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- vertebrata 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 Vertebrate 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 maculte. 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-yolked 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 or toad is a nearly spherical body of from 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. Ttiis 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. [92] of sexual union, and they are thence taken up singly by the open upper extremities of tiietwo oviducts ; through the whole of which canals they descend, and in tlieir 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 [lassed through the oviducts remain fora time accumulateil in large numbers in a ililated part of the canals near their lower end, until the whole or greater [)art of those which are ready to desceml 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 S[)awn 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 stiifjelly, 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 placeil 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 orjother 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 de[)osits 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, liana temporaria, it is of a very’ dark brown ; and it is in different other species of various hues, as * 1 have frequently obseiwed this process, which has been beautifully described and ligui'ed by Mauro Kuscoui 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 [taler part, which appears where the dark part terminates, varies in different spe- cies and is greater in [troportion to the de- gree of advancement of the ova. In some species, as in the Ahjtes 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 v-esicle 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. I Entwickelungsg. der Geburtshoelferkrbte, Solo- thurn, 1842. OVUM. 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 the 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 yolk 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-suhstance 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 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 [93] outlines ; they have also considerable firmness, resisting pressure, but by force may he 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 steariue 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- scrihed by J. Miiller as forming the greater part of the yolk-substance in the Sharks and Rays, and which also exist in the ova of Cephalopodous Mollusca.-|' The germinal vesicle of the Batrachian ovum is of very large proportionate size. According to Vogt, in the Alytes obstetricans 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 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 hai'dened by some re-agent, — a plan which has been successfully adopted by a variety of observers. Cramer j recommends for this purpose alcohol, or more particularly dilute chromic acid; Newport^ employed alcohol, as I also have done with success ; more recently Rernak || states that he has found a mixture of a solution of sul- phate of copper with alcohol, to which a few drojis 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 apprcar- 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. fiu' Wissensch. Zool. vol. v. p. 241. t See J. Muller, iiber die Glatten Hai des Aristo- leles, 1842, p. 36. J Bemerk. iiber das Zellenleben in der Enttvick. des Frbscheies, in Muller’s Archiv. 1848, p. 20. § Researches on the Impregnation of the Am phibia. First Series, in Phil. Trans, for 1851, p. 169. ef seq. II Untersuch. fiber 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 macidae, 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 u|)per than the lower [>art 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 [jole of the yolk, through the yolk- substance, to the surface of tlie 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 liy the slightest force ap[)lied 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. Remakf, 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 containsatmost seasons aconsiderable * 2"''* Mein, sur la Generation, &e., in Annal. des Scien. Nat 1824, tom. ii. p. 104. t Loo. cit. p. 127. numher 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 siqipose to comprise those de- stined for succeeding breetling 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 [lediculated ca|)sules 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. ft 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 ve.sicle in this state, and I have generally observed the macula, even in the earliest stages, to be multiple, or to con- sist of several maculas. Still it is undoubted that, in the earliest period, there are fewer maculas 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- roumled 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 ; wdiich 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. Newi)ort describes the germinal vesicle of the frog’s ovum as micleated, even when half-grown. He also speaks of the corpuscles of the yolk sub- stance as “nucleated cells” (1st Series, p. t7(i.) ; but this is quite inconsistent with the statements of most other observers. OVUM. [95] 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 tliose half-grown, any zona or other proper vitelline membrane ; ami it is obvious that what some authors* have described as such could be nothing more than the distinct surface of the pi imitive 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 dilferent 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-7iucleus. This mass may' easily' be seen in ovisacs of the common frog of from 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 spreatls itself round the germinal vesicle, f Leuckart, however, states that this body is not invariably [jresent, 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 ra()idly ; 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. J See V. Cavus in Zeitsch. fiir Wissen. Zool. vol. ii. p. 103. ; and Ecker in his new edition of K. Wagner’s leones Physiolog. descript, of Tab. xxiii. 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 in diameter: in A the follicular membr.ane 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 wdthin are seen in pro- file towards the margin, and full towards the centre (in a) ■n'here their granular contents and nuclei are distinct. In the centre of b the large germinal vesi- cle ■with numerous maculaj is seen ; around it a clear space w'hich 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-clefined for a time, and there appears to be some fluid or different substance interposed between it and the OVUM. [96] 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 tabidar 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 ofdevelopment that, along with a proportional enlargement of the yolk, the darkest kind of pigment is dejiosited among the corpuscles on the upper surface. The gradual extension of this coloured layer overagreaterportion of the surface of^the yolk from the up|)er 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 proceeils 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 e[)ithelial 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 |troper 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 tbe 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 pecidiar 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 tabidar corpuscles. Vogt described them as scattered through the whole of the superficial yolk-substance in the Alytes obstetricaiis, 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. f Muller’s Archiv. 1848, p. 23. OVUM. 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^ 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 closelj' 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. j Epistola de Ovi, &c., Fig. xxv. Siipp. [97 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 I’hemisphere brim une taclte 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 peicees, ee qui met a decouvert la bouillie brune que renferme I’ovule. Pour s’en assurer il suffit de vider I’oeuf et d’exa- miner a la loupe les membranes transparentes qui sont restees intactes dans toutes leurs parties, sauf I’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 Deuxifeme Memoire sur la Generation : — Developperaent de I’ceuf des Batraciens, &c., par MM. Prevost et Dumas, in Annal. des Scieu. Nat. tom. ii. 1824, p. 104. [«] OVUM. [981 Salamanclrina 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 kimls of elements ; and the germinal vesicle is of con- siilerable 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. C(i *. 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 immetliately 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 proSle 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. 1 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 ofgranular substance when water is added to it. This ehange 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 [jrecipitated 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 in 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 Eoy. Soc. of Lond. 1852, p. 149. t See Retzius in Muller’s Archiv. for 1855, p. 34. OVUM. 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 in ova of Jg". It is 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 maculte ; 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 ceils 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. f * Resumd d’un Travail sur I’Embiyog^nie du Brochet, de la Perche, et de I’Ecrevisse, in Amial. des Scien. Nat. 1854, tom. i. p. 237. et seq. t M. Coste (Comptes renclus, 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. [99] The membranes of the ripe ovarian ovum of osseous fishes have been clescribed 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 wdiich 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 sajing 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, tliat 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 Fisclie, Leipzig, 1835. [h 2] OVUM. [100] f: enus was not entirel3' 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 Perea fliiviatilis by Professor Muller of Berlin. In this fish INIuller 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.f The tubes have a slight spiral winding as they pass tltrongh. That they are really hollow tubes Midler ascertained b}' finding that he was able to press portions of the coloured oily contents of the yolk through them. Muller 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 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 tuimed towards the observer so as to show the punctated or dotted marking produced by the ex- ternal apertures of the line canals which i-un 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 iu 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 that of their nuclei * Emhryog^nie des Saumons, Neufchatel, 1842. t Muller’s Archiy. for 1854, p. 186. Ransom’s observations, however, it appears that the structure described by Muller 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 -j-uhru"' 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 and the tubes them- selves or double lines bounding them were not more than 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 G8 * 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 Muller, 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. Muller 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 1 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- observation in the first-mentioned fish,^ mg that in impregnation the spermatozoa entered ^ the ovum only through this aperture or mi- ; cropyle. As this is the first instance inj which the existence of this aperture and its] relation to the process of fecundation have] been ascertained by direct observation in a1 vertebrate animal, I will describe it more fully] from Dr. Ransom’s paper to the Royal So-J ciety of London*, and from farther inform-^ j ation which he has obligingly furnished to mej''fl in private. I may also mention that I hav^ fully confirmed Ransom’s observations as t^ Proceedings of Roy. Soc. 1854, Nov. 23rd. OVUM. A B 3Iicropyle of the ovum in Osseous Fishes. 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 [lart 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 o^•^^m was about jL" ; the thickness of the external membrane ; the width of the base of the funnel about ; the depth of the funnel jA" ; the diameter of the micro- pyle aperture at the apex 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. Lioi] the existence of the micropyle in the ova 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 Eansom’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 to 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 w'all 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 granular matter being mingled w ith the con- OVUM. [102] tents of tlie 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 inicropyle. I shall afterwards have to state the more mimerous instances in which, following its first discovery by J. Miiller in the Holo- tluiria, a inicropyle lias 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 I'ecundation 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 * Eutwickelungsgeschichte der Fische, Leipzig, 1835, p. 9. ligs. 1. and 2. f De Ovi Mammal. &c., pi. xxv. Fig. 69 #. Development of the ova of Gasterosteus. 1 A. n. c. D. Four ova of the Stickleback in the j 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- T tre has scarcely any perceptible membrane or wall, * but resembles a gelatinous mass in which the small 'I number of maculte are developed; there is as yet noy yolk, but only a slightly turbid fluid substance filling the space between the ovisac and the ger- * minal vesicle: delicate epithelial cells project from i the inner surface of the ovisac. 1; In B. the maculae have increased in number, t the germinal vesicle, as well as all the other parts, ha.s t' increased in size, the fine granules of the yolk sub- ' stance have begun to be deposited towards the pei'iphery, 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. the maculae 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. In D. .jljj", although the number of maculaj 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 is also slightly perceptible mfig. c. The dimensions of the several parts in these dif- ferent specimens were as follows : Ovisac A. ■0025 B. •004 c. •0056 i>. •007 Yolk - - — •0042 •005 Germinal vesicle - •001 •0016 •0025 •0026 Maculie •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 much 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 clear, 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 cells, 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 a[)pear, 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 J, entirely to the effusion of the contents of the germinal vesicle. * Lereboullet, loc. cit. t Retzius, loc, cit. I Hist. gen. et part, du Developp. des Corps organ, tom. i. [103] 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 showm, 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 hav^e 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 viviparusf ; 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 vrithin the capsule, f Abhandlung. zur Entwick. part. if. p. 4. j Muller’s Archiv. for 1854, p. 376. fig. 6. [h I] OVUM. [lOi] 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 tlie 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 ru|)ture 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 arc surrounded by a considerable amount of secreted albuminous matter, by which in some fishes the ova are covered whcTi 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 |)rojcctions ; but tbe 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 externtd 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 S()ecimens 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 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 ilo 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, j- * Jliiller’s Arcliiv. 1855, p. 23. See plates IV. and V. t 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. filr Wissen. Zool., containing a notice of the discovery of the micropyle in the Salmo salar, and S. faj'io, 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. Kansom’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 tbe 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 tbe 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,witb 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 Sliarpey and myself in August and September. In the beginning of January, 1855, Ur. 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 micro])yle. 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 Planarite, 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. 1st. Large-Polked 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 maculm, 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 184+.* The ova of the Sepia are deposited singly, but are attached in numbers close together by pedicles to the stalks of Algte and other marine productions. Those of Loligo are arranged in small 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, 1844. 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 w’hich the outer part of the yolk and the vitelline membrane undergo during the greater part of the time occupied by the grow'th 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 Kblliker. 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 w’hich folds of the vitel- line membrane pass so as to line them to the bottom, somewhat after the manner in which thepia mater descends into the sulci of the brain, but without the same convoluted form. This has been represented by Kolliker in the Sepia, and I 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. OVUM. [106] 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 comeat 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 pccidiar 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 ; covering, there is a delicate transparent vitel- ^ line membrane. The germinal vesicle is of pro- ^ : portionately large size. Its macula is at first 'S single ; but in the course of the growth of the Xl ovum it becomes multiple, or diffused as a finely S granular or molecular substance throughout X the vesicle. f The germinal vesicle is situated ^ in a vitelline or germinal area composed of fine « granules, in which without doubt the limited ra process ofsegmentation 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 p|ll of more than one layer of substance. The I* outer and inner are described as being gene-'% rally more clear, dense, and homogeneous the middle one, in some insects at least, pre-tj^j seating greater varieties of structure, and nott^l 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 SeptembeiVa. 1854 J ; but the discovery appears to have® been made simultaneously by Leuckart, whoB has given a most interesting and elaborate J description of this apparatus, and of the?' minute structure of the membranes, in a great k] variety of insects, in a memoir recently pub^J lished by him.$ Meissner described several varieties of thej^ * This has reference to the position they occupyj' during their formation in the passages of the femal^ parent. t See R. Wagner’s Prodromus Hist. General. J Zeitsch. fiir Wissen. Zool. vol. v., p. 272. “ § Memoir on the Micropyle and Minute Structure, OVUM. Fig. 75*. Micropyle in the ovum of Insects. (^From Sleissner.) a. A portion of the upper pole of the ovum of Musca voinitoria 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 Muller’s Archiv. Nos. 1. 2. and 3., February and July, 1855, p. 90., et 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, [111] 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 of the ovum of Lepidoptera. (^From Leuckart.') A. Side view of the upper part of the ovum o^ Sphinx Populi, showing the micropyle, the r.adiated 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 stmcture 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 hasstated, 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, amountino- 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 [112] OVUM. Ovum and 31icropyle of Dipterous Insects. (^From Leuckart,') A. Ovum of IMelophagus ovinus (Muscida). 1. Tlie entire ovum, ])reseiiting at its upper part the adlierent mass of spermatozoa close to the micro- pyle. 2. This upper part uiore highly magnilied, 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 micropjde 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 poles. 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 Steinji 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. t Prodromus, Hist. Gener. p. 9., and Beitrage zur Entwickel., &c. p. 42. See fig. 40. Append, of Cyclop. Anat. and Physiol. ± Zeugung, p. 803. § Vergleich. Anat. und Physiol, der Insecten, Berlin, 1847. OVUM. [113] Fig. 79* h. A small portion of the upper part of the ova- rian tube from the larva of Saturnia Carpiui. 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. 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 TOth 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- Snpp. loped hemispherical ovum m 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 preparatoiy 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 meredeficiency 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 notin 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. * Zeitscli. fUr Wissen. Zool., vol. i. p. 190. llj OVUM, [114] Car^'se, 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 in diameter, or of a small mass of these cells at- tached in the same place as that occupied by the ovary in the ovipaious 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 falling 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 legards 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. Arachvida. — The ova of nearly all the higher Aiachnida 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 Insect.s, of separate sexes. The Tar- digrada are hermaphiodite ; and in these as well as some other simpler Arachnida, as Pycnogonida and Acari, the ovum, though pro[)ovtionally 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, smalleJ' 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 huge, placed eccentrically, and possesses a macula, which in some genera is simple and flattened, as in the Scorpion, in others multi[)le 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 pcdiculated ovi-capsules. Ac- cording to Wittich, V. Carusj-, 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- pleand without a macula, which last soon after- Fig. 80*. a. Small fragment of the ovary of Epeira diadema from which three ova project in the earlj^ stage of ' their development previous to the formation of ^ the yolk; the germinal vesicles are enclosed in the I membrane formed by the bulging out of the ovarian substance. i h. 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. §• 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, &o., Muller’s Archiv. for 1849, p. 113. f Zcitsch. fur Wissen. Zook, vol. ii., 1850, p. 97. OVUM. wards appears as a small dot or nucleolus. The yolk begins, in the sanie 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 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 Cams, 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 exce[)tion, 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 f ; 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 Kaufmann of Lucerne on the development of the Tardigrada, as afford- ing clear and beautiful illustrations of the process of segmentation, w’hich 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, t Zeitsch. fur Wissen. Zook, vol. iii., p. 220. See Plate VI., figs. 3. to 11. § Monograph of the Sub-class Cin'hipedia, &c., printed by the Ray Society, 1854, p. 27, &c. [113] 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 vary ing 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 Articulata, 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 f ; 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 Ilathke]:, by Erdl^, R. Wag- ner II , Leuckartf, 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 difiicult 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 con.siderable size, having the aspect of oil globules, in which the colouring matter chiefly resides. In some ova these globules attain the size of ^4^ of an inch. There is also a more fluid granular matter in the }'olk, 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 Reseaixhes, 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. X Entwickel. des Flnsskrebses, 1829 ; in Bur- dach’s Physiologie, vol. ii. 1837 ; in his Abhandl. zur Bildung und Entwickel. Gesch. &c., 1833; in Dissert, de Animal. Crustac. General. 1844 ; and various other treatises. § Entwickel. des Hummereies, 1843. II Prodrom. Hist. General., 1836. ^ Article Zeugung. ** On Argulus foUaceus in Zeitsch. fiir Wissen. Zook, vol. ii. [i 2] OVUM, [110] ing a single nucleus, in others multiple nia- cnliE. The formation of the ova may be observed ■with ease in any of the smaller isopodous Crustacea. According to Lenckart in 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 tbe 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- amj)le, when the ova are about *** diameter. In many of the Crustacea tbe 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 F}g. 81*. Ephippial OMum of the Daphnlda. From Baird.') The figure represents a profile view of the female of Moina rectirostris (one of the Daphnidaj) 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 marsnpia or pouches appended to the genital orifices of the parent, in which tbe ova are retained during the formation of the young. In all the bisexual Crustacea the ova are fecundated while still within the body of tbe 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 tbe 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 foimed 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 epbippial 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 * N«t. Hist, of the British Entomostraca, Bay * Soc. Public., p. 79. OVUM. 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 Siebold-j- states that these hybernating 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 Annulata. — 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 Uiriidinea, 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 H, there are peculiarities of structure * Mem. of the St. Petersburg Acad., 1848, tom. vi., p. 162. t Compar. Anat. j See Burnett, loc. cit., p. 353 ; Zencker, liber die DaphuoidiE in Muller’s Archiv., 1851, p. 112; and Leydig, Uber Arteinia salina und Branchipus stagnalis, in Zeitsch. fiir Wissen. Zool., vol. iii. 1851, p. 297. § Suctoria, terricola, errantia, and tubicola. II 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 Seien. Nat., 1848, vol. x. p. 153, in which, in addition to his own researches, are duly recorded those of previous observers. ^ Zeitsch. fiir Wissen. Zool., vol. i. p. 123. [117] 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 lay'er 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 cellulr.r 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, Meissnerf 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 the Lunibricus during fecundation. (^From Aleissner.') 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. fiir Wissen. Zool. vol. vi. [' 3] OVUM. LI 18] 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 tliem, the clear primitive vitelline substance. In this substance opaque granules, which are at first colourless, are subsequently dej)Osited; and as these e.xtend 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-jij", and its macula of ^ 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 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 Leydig, 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. J * Quatrefages, it is to be observed, designates tlie enveloping membrane ovarian and not vitel- line membrane, which last he holds is wanting in these ova. t 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 Uyclopajdia, to which 1 must refer the reader ; in Grube’s Unter- sueb, iiber die Entwickel. der Clepsine, Kbnigsberg, 1844. II. Kocb, Ein Worte zur Entwick. von Eunice, with an Appendix by Kblliker, on Exogone and Cystonereis. I See Leydig, On the Structure and Systematic Position of the Kotifera, &c., in Zeitsch. fUr Wisseu. 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 Dalrymplef, Others seem to be hermaphro- dite, as in Megalotrocha, described by Kbl- liker]; ; in Euchlanis, by Schmidt^ ; and in Lacinularia socialis, by Leydig.|| But ac- cording to Huxley H, 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 maculie; 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. II Zeitsch. fiir Wissen. Zook, vol. iii. ^ IMicroscop. Soc. Trans, p. 1. in vol. i. of Microsc. Journal, 1853. OVUM. phenomena of fecundation been minutelj' 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 jolk 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 Bracbionus, 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 Daplinia, and contain no apparent germinal vesicle. Mr. ITuxlev|- 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 ovtim in Lacinnlaria Socialis. (^From Huxley.') A. represents a portion of the ovaiy 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 bis 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. [119] 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 oidinary ones ; while Huxley considers them rather as pecu- liar buds like those of Aphis or Gyrodactylus.* Tui bellana. — Under this class three orders of the animals allied to the Planaria may he 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 Dendroccela, and the Nemertides or Miococla. 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 -j-; but the history of the structure and formation of the ova is still far from being complete. The ova of the Planariae are of \rarious 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 gei minal 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 j'olks are formed in separate organs, as in the trematode animals, to which the Planarias are nearly allied, but in some, as Macrostomum, 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 Planarite, 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 Von Siebold’s Comparative Anatomy, p. 150. f Mem. sur quelques Planariees Marines, in Annul, des Scien. Nat. 1845, tom. iv. p. 169 ; and Me'm. sur la Famille des Nemertiens (Nemertea), id. lib. 1846, tom. vi., p. 269. The Ilhabdocoela are known chiefly by the researches of Schmidt, Die Ilhabdoccelen Strudelwiirmer des siissen Was- sers, Jena, 1848; and of Schultz, Beitriige ziir Geschichte der Turbellarien, 1851. [i 4] OVUM. [120] or is rather a collection or aggregation of a nuinber 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. F,ntozoa. — The ovology of the Ilelmintha 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 witliin the bodies of other animals. From the researcltes on this subject whicli have been prosecuted with great assiduity by a number of observers in recent times, not only liave 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 Trernatoda, 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 ailded, is to be looked upon also as a con- stituent part of the ovary, and may be called theyolk-formingor 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. 140. 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 mgsta.v. A. Earliest stage of the ova as they are found in the coecal or uppermost part of the ovarian tube ; i 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 fiat surfaces, and one i with its thin edge towards the observer. The ex- jj ternal dotted line represents the surface of the 1 basement substance of the yolk in which the opaque j 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 ijj stage, when it has met with the spermatic cor- OVUM. 1121] puscles ; Tvliich are held by Nelson thus to pene- ti'ate or gain access to the vitelline substance. E. 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 v/hen the minute ova have somewhat in- creased in size, the outline of this clearer basement substance of the j'olk 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 Loud. 1852, p. 563., pi. 28, figs. 48. and 50. Fig. 86*. 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 ef 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 -;vith 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. G. 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 he caused by the rapid imbibition of fluid at the time the changes above mentioned are taking place, renders them pecidiarly liable to be impressed by the spermatic corpuscles at Fig. 87*. Development of ova hi Jilermrs albicans, belonging to the Gordiacei. (From dieissner.) a. Germ -cells from the upper or ccecal 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. /. Two similar ova now ripe, a part of one of them is artificially bm’st, 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 inicropyle apertm'e. this period; and Nelson is of opinion that these corpuscles even penetrate completely into the yolk-snbstance, 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. BaiTy 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 stilt in that paper, and in a special memoir on the subject, publi.shed in the Zeitsch. fiir 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. IVith 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. 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 I the tube, and the ova are suspended to it by ' pedicles, supposed by Meissner to form micropyle ■ apertures when they are detached. b. View giv^en by Meissner of a set of the nearly , ripe ova of Ascaris mystax, which he conceives are , thus connected bj' pedicles to a central axis. ' c. Two mature ova of the same surrounded and in part penetrated by’ spermatic corpuscles. At the i narrow angles of these ova a spermatozoon is seen I passing into the interior by what Meissner has 1 regarded as a micropyle formed by the detached I pedicle. In the ovum to the right a spermatic cor- j puscle is seen in the vitelline substance. The 1 existence of such a micropyle aperture and pedicu- j lated attachment of the ova in the Ascarides I re- I g_ard as doubtful. [12.3] 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- hifurcus. [From Fleissner.) 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 OVUM. 1124] in most but not in all of which segmentation is complete. This process was first made known through tlie interesting researches of Kdlliker* * * §, in Muller’s Archiv., 1843, p. 68, and Bagge, in his Inaugural Dissertation. -f- 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 MeissnerJ, gives a representation of a remarkable form of the external capsule of the ova occurring in some of the Gordiacei (Mermis nigrcscensj. Fig. 90*. Mature ova of 3Iermh nigrescens. (^From 3Ieissncr.') This figure is introduced to show the very pe- culiar capsule ill which the ovum is enclosed. a. Ovum taken from the uterus with embrjm enclosed; the chorion and shell capsule with cha- laza; or brush-like processes attached to the latter. b, c. The shell capsule c burst across the equa- torial groove, allows the ovum h 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 dee[t 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 elear nucleated eells alone being produced, in the other the opaque granular fatty matter which furnishes the vitellus. This arrange- ment was first deseribed 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 Eutozoa. I Dissert, inaug. de Erolutione Strongyli auri- cularis et AscaritUs acuminatas, Erlangae, 1841. t Zeitsch. fur Wissen. Zool. vii. pi. ii. § Wiegmann’s Archiv., 1836, p. 217, Tail, vi., and Muller’s Archiv. 1836, p. 232, Tnfl. x., fig. 1. stages of development. The vitelline organ is double, each one consisting of coecal 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, olfers 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- 1 taneously in the posterior or oldest segments j of the body. Van Beneden has, in his recent 5 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 orj proglottides of a variety of Cestoid worms.1 The ova originate in the first mentioned ofJ these organs as germinal vesicles, and, passing j into the vitelligenous part, meet with the! yolk-masses formed there. Near the samej place is situated the seminal vesicle, fromj which, doubtless, the spermatic substance! easily reaches the ovum as it descends in the! course of its formation. The ova then ac-|J quire an external envelope, and pass into the! cavity termed a uterus. As they come 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. t Mem. sur les Vers Cestoides. Acad. Roy. de Belgique, tom. 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 combination 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 striae 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, j- 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, Coenurus, and Echi- nococcus, are only larval 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. DuvernEea), described by Quatrefagesj; 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 Kblliker in Muller’s Archiv. for 1843, p. 92 ; Tail, vii., fig. 44. t 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 Parasiten des Menschen, &c., Leipzig, 1855. t 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]; , 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 lajmr 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- * Derbfes, in Annal. des Scien. Nat. 1847, 3® Ser. vol. viii., p. 80, and Leydig in Muller’s Archiv. for 1854, p. 312. t Wiegmann’s Archiv. 1844, and Annal. des Scien. Nat, S'’ ser., vol. ii. p. 190. X Leuckai-t in Bischoff’s Wiederlegung, Sec., 1854, and Leydig, loc. cit. OVUM. [126] 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. Fig. 91*. Ovum and Micropyle in Ilohihuria tubulosa. {^From Leydig.') a, h. 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. e. 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 rvith 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- served in other Echinodermata, viz. by J. Muller in Ophiothrix fragilis, in which he .states its diameter to be and by bis son MaxMiillerin 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 tlie formation of the germinal vesicles. These have been * The micropyle wms represented in the o'vuira of Holothuria tubulosa by R. IVagner in his leones Zootomica;, tab. xxxii., fig. 12., before its nature was known. The first discovery of a micropyle in the animal ovum is therefore due to J. Muller. The next observations of a similar nature are those of Lcuckart 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.* Polyphia. — 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 tlieir general organisation approach very nearly the tunicate Mollusca, but which in their mode of reproduction resemble closely some of the ^ j Polypes. . ^ The ova of the common Hydra, already re- i|B 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 1 Bryozoa. In the Tubularida; 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],; ' but as the phenomena of the production of these ova have been fully described by Pro- fessor Ilymer Jones in the article Poi.ypifer it is unnecessary to enter into farther details with regard to the process in this place. % * In addition to the memoirs previously quoted,'!; descrijitions of the ova of Echinodermata will be J 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 Cams and Otto’s Tabula; Anat. Conipar. ; those of Echinus by Derbfes, loc. cit. ; and b}' Krolm in Beitr. zur Entwick. der Seeigel- larven, Heidelberg, 1849, &c. t Sir .lohn Dalzell, Remarkable Animals of Scotland, &c. J Duraortier and Van Beneden’s Researches, in Mem. of the Acad, of Belgium, 1842, tom. xvi. OVUM. In Hyclractinia 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 W'ere 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 Hytlrozoa, as in the com- mon green polype, the ova are single, while in others as in Hydra 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, Alcyoniurn, 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 ajipropriately 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 Srdl^', 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 * leones Zootomic*. t See p. 23. andAV. 19- of this article. t Mem. sur les I’olypes d’Eau douce. Acad, de Belgique, 1812. [127; 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 Lnpliopus Bakeri. (^From Fan 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, e. 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 tme ova, as well as by attached buds, which last are then covered by a strong corneous envelope, and have received Fis. 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- Fiff. 94*. Formation of hurls in Paludicclla. (^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 ectoc3’St and en- docyst are seen more distinctly. c. A more advanced stage of the same, internally ; the part from Avhich the embryo pol^’ped 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 de.scribe a propagation by means of buds and by ova provided with the strong horny envelope. In Alc3'onella 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 diflTerence 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 long been known that the so-called Winter ovum and embryo of Lophojms Crystallinus. {From Van Beneden and Dumortier.') 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 Allman 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 arc 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. Acalephae. — 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 Medusm 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- 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 Medusas, are of separate sex ; and the}' 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 Algm, 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 w'hich 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. Thiero, 1839. t 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 Entwdckelungsgeschichte untersucht.” 4to. Leipzig, 1854. 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. h. 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 oi the Polyzoa to the British Association. Sei Trans, for 1850, p. 320. OVUM. [130] substance of the sponge, and certain spherical bodies enclosed by dense cajisules, 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- i her 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.-l- 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 [ihenomena 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, REC.Vt'ITULATION 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 Cai'ter in Annals of Nat. Hist. voL iv. p. 89. t 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 eai'lier 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 file 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, gemmm, 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 I 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 tlieir more ordinary fissiparous or gemmi- parous mode of multiplication cannot be ad- mitted to have taken ])lace, 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 '1 atmosphere, and of resisting during a long period many of those influences which gene- rally prove inimical to animal development), 1 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. 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- gariiiffi 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 oart of this article, it appears that in a cer- tain number of the invertebrate animals, such IS those which have been referred to under he heads of Echinodermata, Polypina, Aca- epha. Tunicate Mollusca, Trematode and [131] 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 zokls ; 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 w’hich new beings are formed from the intermediate individuals (or so-called nurses of Steen- strnp, 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 [K 2] OVUM. [132] parent or female organ, in whicli the greater part of the organised material first to he em[)loyed 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 tlie 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 liitherto 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 referi ed 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. llecaiiitulation 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 of 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 arc 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 eomposed of very few I)articles. The second principal group comprehends the large-yolked ova, such as those of Birds, Scaly Reptiles, Cartilaginous Fishes, and the Cephalopoda, to which, perhaps, maybe added Insects, Arachnida, and most Crustacea. In this group, the largely developed yolk contains, suspended in its basement, homogeneous sub- j, stance, two kinds of organised corpuscles, viz.; '3 1st, A certain portion of the small granular *i part, similar to that of the small yolked ova, v which occupies a limited but determinate place i| > nviim unrl in ifc fr<=^rmintil VP- ''i' in the ovum, and in its centre the germinal ve- r side is situated ; and 2nd, A larger portion of f spherules, cell-like or other corpuscles ofgreater || magnitude. It is the first or finely granular .n 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 ther, embryo or its accompanying organised parts ] in the progress of their development. In the(j ova of this group, therefore, we distinguish the formative or directly germinal portion of the yolk-substance from the mfArectXy nutritive portion. In these ova, the germinal vesicle is; also proportionally large, and the contents ofj the vesicle, though consisting in the earliest 1 stages of their formation of a single macula, j or of a very small number, very soon become converted into very numerous maculae, orintoij a fine granular pulp. The third, or subordinate group, may cora-ii prehend the ova of Amphibia, or scaleless rep-j' tiles, and osseous fishes, to which, perhaps! may be added some of the invertebrate aiii-ii mals mentioned under the second group. Th(| ova of this group are intermediate in therj structure between those of the first and sc cond ; they have certainly the greatest affinitj with the large-yolked group, but there ar, many gradations among the ova of this kinc among allied species of animals, and it is chief! on the ground of the incompleteness of tbi segmentation that I have thought it proper t arrange them in a separate group. It may be remarked further, that in all an OVUM. 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 flattish 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 tough, 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 Camraarus. (See his Memoir in Zeitsch. fur Wissen. ,Zool. vol. v. p. 284.) [133] and the yolk-substance, &c. are added gra- duallj' 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 maybe 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 [k3] (JVUM [134J 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, liowever, 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 tliere 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 tlie ovarian follicle ; but as the deposit of the finely granular yolk increases, and at a very variable period in difi’erent animals, the vitelline mem- lirane is formed round its exterior. The ad- dition of this covering maybe 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 |)robable that the so-called zona pellucida which constitutes the vitelline membrane of the Mammiferous ovum, takes its origin by the consodidatiou of the superficial part of the basement substance of the ])rimitive 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 wliich 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 wliich 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 maculae 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 [)hysiologists 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 sitnple 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 correspomlence ; 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 refi'ain 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 mammiferous 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 to -jL 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 rdze. 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 Ifr. Huxley in the Brit, and For. Med. Chir. Review for October, 1853. [Kd] OVUM. L13C] 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 luive 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 tlie 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 jjresenting 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 |)laced 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 Is'ematoidea 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 ovi[)arous ani- mals, or to be retained in a uterus or other ]>art 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 ^vhich accompanies the heat of female quadrupeds, the ova may be detected, though uufecimdated, 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 II. Letheby, M. B. in the Philos. Trans, for 1851, p. 57., where two eases are described in which ovules or their remains were detected in the Fallopian tubes of unimpregnated rvomen ■s\-ho 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 macula; of the germinal vesicle become very numerous by their multiplication and sub-divi- sion at an early period ; w'hile in the small- yolked ova, as has been observed in a few animals at least, the increase in the number of the maculce 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 occu[)ied, but what becomes of them lias 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 jiart 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 progen}^ 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 ha? 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. Remak f has been led, by his observations on the Batrachian ovum, to * Arcliiv. der Phy'siol. 1852. Bey’dig in the same. + Untersiicli. iiber die Entwickel. der Wir- bertliiere. OVUM. [137] doubt the correctness of the view hitherto and embryogerm, or with the internal con- o-enerally adopted as to the entire disappear- tents of the ovum. The actual entrance of ance of the germinal vesicle in that instance, the spermatozoa into the ovum has been observed in Mammalia, Batracliia, 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 and holds it as probable that a part of it at least remains in connection with the forma- tion of the embryonie 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 gemmte or buds, in the multiplication of together from the separate organs in which 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 otherw'ise 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 [iroduced ; 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, w'hich 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 Semen. t See especially the recent researches of Kolliker on the Sperm iu Zeitsch. fur. Wissensch. Zool. Yol. vii. 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 18-13 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. Muller, a special aperture or perforation of the egg- covering exists, apparently destined to allow of the more rapid entrance of the spermatic bodies. This micropyle 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 iu 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 OVUM. [138] some other animals, in which, had it been present, it could scarcely have escaped so carefid a scrutiny, 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 K. Wagner and Leuckart, the papers of the late Mr. New[)ort in several recent volumes of the Philosophical Trans- actions, and the learned article by Professor Leuckart on Generation contained in the fourth volume of K. Wagner’s Ilaudbuch der Physiologie. I will only remark in passing tliat from Mr. New[)ort’s ami other researches it aj)pears that while the actual mixture of an appreciable quantity of the spermatic sub- stance is necessary to induce fecundation, the extreme rajiidity with which the action takes j)lace, 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 vvith the idea that it is one of mere combination in substance of the developed contents of the male and female generative products. But whether th.is 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, [)roperty, 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 W'ork in bringing about the sequence in ques- tion. The fecundating power of the semen is an expre,ssion 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 wliich 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 change.s, it appears more probable that a variety of eonditions 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 ceils ; the ovigerm and the sperm- germ. If we may form any general con- clusion from what may be so well observed in Nematoid Worm.s, 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. 1 1 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 tlie 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.' G. Immediate effects of fecundation on the ovum ; segmentation, and first changes ol the ovum related to the commencement of em- br3'onic development. It does not come within the scope of the present article to describe in detad the pi’o- OVUM. [139] cess of fecundation, or the phenomena which In the greater number of instances there is follow it but it may be proper to state here recognised m the mass of the \yhole yolk, or in a ear. There is great dilference in the size of the follicles, some being as much as ^-^th of an inch in diameter, some as small as jj-iJ-g-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 -:rTOth of an ineb. 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 tliey are more or less massed and fused together. Fig. 58. Isolated cells o f ^nature secreting epithelium from the pancreas of the Hat, showhig their opaque granular contents. (Magnijied 4.U0 diameters.') fi. The epithelium is of the glandular type, spheroiilal or [lolygonal in shape, varying in diameter from T^ooth to T^^Ty’^th of an inch, and |iresenting 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- pherae 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 tlie ultimate follicles of the pancreas are cylindrical, while those of the salivary glands are slightly dilated. (.?) 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 gramdes merely marking its situation. (Seeyfg. 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 ap[)earance, a dark spot marking the centre of each follicle, and the number of dark spots showing the number of follicles, w hich, 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. Fig. 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 fig., 57. are never adherent to one another. The less advanced cells, however Epithelium liherated by rupture o f the follicles, show- ing the method of detachment, and the mutual lateral adhesion, of the cells. From the 3Iouse. (^3lag- 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, ;is seen in fig. 59., the convexity coinciding with the follicle-membrane, the concavity with the central space, and the adlierent surfaces of the cells [jresenting 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, imleed, 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 refractiiig appearance, surrounded by a me- dium of much less refracting power, and " PANCREAS. 89 finely granular. These globules are of various shapes, accortliug as they are isolated or coni' Fig. 60. Appearance of homogeneotis globules of various sizes and shapes, occasionally seen in the follicle of the pancreas. From the Rat. (flagnified 200 dia- meters.^ pressed by neighbouring ones. They range in size from ^ to of an inch, and are evi- dently not contained in any cell-membrane. (See 7%. 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.* y. 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 cuiTent 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 I 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 I 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. (^3Iagnifed 150 diameters.') not more frequently visible. I have repre- sented it in fg. 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 the walls of the ultimate ducts : for the fibrous which pervatles 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 a[)- parently in a single stratum, and presenting a heautifid honeycomb appearance of closely- packeil hexagons and pentagons, when looked at on its free surface. Further u[), 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 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 o f an inch in diameter. From a Rabbit, {JMagnified oUO diameters,') There is every probability of the existence of a basement membrane here as in other sub-c|)ithelial situations, and it is probably continuous with that which alone constitutes 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 ini[)ly the non-existence of this mem- brane in the larger ducts, where they are not so fused. Capillaries. — The arrangement of the ca- pillaries remarkably 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 (^Jig. 64.). Fig. 64. Arrangement' o f the capillaries o f the pancreas. From a minute lolinle o f the pancreas of a young Babbit. (^3Iagnifed 80 diameters.) III. Comparative Anatomy. invertehrata. — Certain organs connected with the alimentary canal have in some of the higher invertehrata 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 Scyllaga. 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 lamin.T, 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. Vertehrata. — 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 pj/fon'c 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 t wo 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 Ainphiprion, in the Angler (Lo2)hius piscatorius), Turbot {Pleuronectes ma.nmus'), and Mormyrus there are two ; in the Perch(Pcrca JJuviatilis), the percoid Popes, the Asprodes and Diploprions, three ; in the Miller’s Thumb (Cuttiis gobio), and Father Lasher {Coitus scorjAus'), from four to nine ; in the Gurnard {Trigla), from five to nine ; in Scorpaena and Holocentrum, six and up- wards ; in the Pilchard {Cupea jnlcardus), and Lump-fish {Cyclopterus lumpus), there are fifty, and upwards of fifty in the Tunny {Scomber thynmis) ; 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 cmca 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 g/a'dius), 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 SalmonidEe and Clupeid®, 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, Malthreus, 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 Cdr\t(Cyj}rinus)-, 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 cmca, the mucous membrane at the pylorus suddenly becomes thick, vascular, and spongy, and continues so for about an inch ; and on pressure an abnndant 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 SalinoindEe, the Clypeidte and Scomberidm, seem to indicate this ; in these last these pyloric caeca exhibit a remarkable complexity. In the Turbot {Pleuronectes maximus) these cffica are seen in their most rudimentary 92 PANCREAS. form; they are two in niiml)er, ample, conical, anil recurved, [)rojecting back from the dno- demnn at its very commencement, so as to give it a barbed or arrow-head appearance, as seen in the drawing (Jig. 05.). The stomach in this fish is very small, and the duodenum Fig. 65. 66.) : the upper five unite together at their bases, and open into the duodenum, close to the pylorus by one orifice ; the last four open separately, each by its own orifice, in linear series along the duodenum. In the Gadktce, as in the whiting (y%. 67.), the caeca are arranged in the form of a ring, Fig. 07. Pyloric cocca of the Turhot. a, ODSophagus ; h, stomadi ; c, intestine. (Drawn one-third the natural diameter.) very large, and the food probably passes into the intestine with but little ilelay. The caeca in tins case must be considered an exception to the ride 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 stufied with taeniae, with which also the intestine was filled. Pyloric cceca of the Sjirat ( Clupcca spi-attzis'). fi, oesophagus ; h, stomach; c, intestine. (Na- tural size.) In the Sprat, the pyloric caeca are nine in number, long, slender, and simple (see Jig. One of the four hunches of pyloric appendages of the Whiting, isolated; showing their union and reunion till at length they end in a single tube. Alimentary canal of the Whiting (Merlangus vul- garis'), showing the pile of caca around the pylorus. (One half the 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 aire 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 cazea, there are a hundred and twenty Fig. 68. Fig. 66. PANCREAS. 93 in all. The appearance of the frill of pyloric caeca is shown in fig. Ci, and one of the bunches separate in fig. 68. In the Salmon this apparatus of caeca is nmeh more voluminous. It is not condensed around a particular portion of the intestine, but extends linearly, from close to the duo- denum for a distance of about eight inches along the intestinal wall; each caecum opens by its own separate orifice. There is no coalescence or fusion, so that on looking on the inside of the intestine there are seen as many orifices as caeca; they form a double row on each side, so that altogether there are four rows, and are arranged with the utmost regularity. The amount of secreting surface oV these caeca must be very great ; some of them are ten inches long, and as big round as a tobacco-pipe; they rapidly Fig. 69. increase in length from the first three down- wartls, and the third from the stomach is generally the longest. They then gradually diminish, slightly in calibre, considerably in length, to those furthest down the intestine, which are about three inches long. Altogether the secreting surface of these caeca must con- siderably exceed that of the rest of the ali- mentary canal, and the whole apparatus, taken together, is next to the liver, by far the largest of tiie viscera. Each double row con- tains about thirty, so that altogether there are sixty caeca, and as the average length of each caecum is 6^ inches, the whole length of secreting surface must be 390 inches, or upwards of 32 feet. In their internal ultimate structure these cteca exhibit considerable variety ; in many the mu- cous surface is closel}’ laminated ; in some it is covered with flattened, fused villi with crypts thickly planted between their bases. In the Herring {Jig. 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 -4^ of an inch in diameter, very evenly and geo- metrically arranged, and each filled with a mass of epithelium. The septa between themap[)earto 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 bey'ond 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’ ])eculiar to give a figure of it. Are|)resents the apiiearance 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 cteca, and assert that many fish pos- sess, over and above them, a true glandular pancreas, analogous in struc- ture to the [tancreas 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 o])ening into the intestine by the side of the cystic ; he also thought that he had seen traces of a pancreatic duct in the piA'c. 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 Siluriai glanis MM. Brandt and Ratzebourg have taken for the pan- Fortion of the alimentary canal of the Salmon {Sahno siilar), showing one double row of ccecal appendages and the pyloric extremity of the other. a, (Esophagus; 6, stomach; c, pylorus; d, small intestine; e, gall-duct. (One-third the natural diameter.) 9-1. PANCREAS. creas a glandular body very like the liver in a|)[)earance, stretched as a layer between the Fig. 70. B Mucus membrane o f the 'interior o f the pyloric caecum of a llerriny (^Clupiea harenyus). A, the surface seen vertically, sliowiug the honey- comb apjiearance formed liy the septa 8ei>arating the masses of epithelium. (Magnilied 150 dia- meters.) B, a section vertical to the snrhice, shoiving the flattened spheroidal shape of the acuvuli of epithe- lium, and the amount of projection of the septa between them. (Magnified 00 diameters ) foUlsof thegastro-liepatic omentum, enveloping the cystic canal and accompanying it as tar as the intestine. These three e.vamplcs of mala- cocopterygions fish have no pyloric caeca, and tliis glandular structure might be considered as re|)lacing them ; but Alessaudrini has also de- scribed in the sturgeon, the walls of whose in- testinal canal are particularly glandulons and in whic!' the pancreatic catca form an elaborate apparatus, a proper pancreas with an excretory duct opening into the intestine in the middle of a tubiform papilla about an ineb from the pyloric orifice. In this last case Cuvier be- lieved the bod}’ indicateil as the pancreas to be a lobe of the liver. “ The tubiform pa- pilla,” be 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 ciil-dc-sac ; in the other the fibre wbich was introduced conducted to a canal wliich took a direction towards the liver. I have clearly seen an excretory duct in a very large silurus, piercing the intestine of the side of the choledoch ; but that canal was, in my opinion, hepatic, for the glandular substance taken as the 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 jfikc 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 car2>, where Meckel could discover neither a pancreas nor pancreatic duct, in spite of the indications of Weber.” Still more recently Stannius has enumerated many fish in which a ptirenchy- matons 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. Iie])tilia. — 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 Batrachut, the pancreas is situated in a proper mesentery or meso-gastrium of its own, extending between the lesser enr- 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. 7 1.) 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 ajjposition with the duodenum all the way Fig. 71. Pancreas of (tie Frog, shown by throwing up the stomach, and exhibiting the under surface of the mesoyastrinm. a, cESophagus; b, stomach; c, pylorus; d, duo- deimm ; e, small intestines; t, liver;/;, 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 carefid dissection could not reveal a proper duct ; probably small ducts from diflerent PANCREAS. 95 parts of the gland open into the biliarj duct as it passes through. The organ maintains tlie 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 Ceecilia albi- ventris it is thick, and pyramidal, and in the Ccecilia interrupla, lumhricoides, and den- tata, 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 Angitis and Ccecilia 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 ap[>aratus with which their alimentary canal is furnished. In the Lacer- tidcB, and Iguanidce, the pancreas is very much developed. Chelonia. “ In many respects,” says Cuvier, “ the animals of this order are in the same conditions as birtls. 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 ini[)airs the closeness of the analogy. In the com- mon turtle, the pancreas {Jig. 72.) firmly ad- Fig. 72. 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, anil 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 veiy analogous to that already described in the human sub- ject. The gland substance has a very peculiar aijpearance ; 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 di.stinct 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 tlieir structure can be distinguished. When ruptured by pressure, their contents escape, ami are seen to consist of two very distinct materials ; one, the afore- said fine granular matter ; tlie other of clear, spherical, uninuclear cells of about 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 oriiice, and in a way admirably adapted for [ireventing 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 wliich the bile duct terminates is opened iqi, it is found to lead into a lacuna, or cul-(ic-mc\ 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 |)a[)illa 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. ylves. The pancreas of birds is propor- tionally larger than in any other animals; and when we remember their deficiency in salivary a[)paratus, its great development vvouUl 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 mail}', two anti three, and that they open b^' separate orifices, and often at a considerable tlistance 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 suhjected 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 (//§•. 73.); the duo- F/g. 73. Pancreas of the common Goose {Anas anser), show- inq 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 po.si- tion by the gastro-he|)atic and gastro-colic omenta, which sometimes simply attach it to the border of the intestine, and sometimes allow it to be fiee 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 thi'ee 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 diflerent 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 sepai’ate 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 Brown Vulture Common Eagle Golden Eagle Aquifa Ossifraga Owl - 1. Raptores. 1 p. H. 2 P. 3 P. C. Duv. - H. P C. Duv. . II. C. P. Cuvier. - 1 P. H. 2 P. 3 P. C. Perrault - 1 P. 2 P. 3 P. H. c. Cuvier. II. Insessores. Night-jar - 1 H. 1 P. 1 C. 1 1 1 Crow - - 1 IP. 1 2 P. 1 11. 1 C. 1 3 P. 1 Picus (Genus') Green Woodpecker Parrot Blue Macaw III SCANSORES. 1 P. 2 P. 3 P. C. 1 P. 2 P. 3 P. C. H. ] H. 1 P. 2 P. 2 II, 1 H. {V.'-} Cuvier. Cuvier. Meckel. Cuvier. Cuvier. Duv. IV. Crax (Genus) - 1 P. 2 P. Crax Globicera - 1 P. 2 P. Common Cock . 1 P. 2 P. Quail - . P. H. Pigeon - 1 II. 1 P. Bustard - 1 P. 2 P. Ib. 1 P. 2 P. Cassary - P. C. Rhea Americana - H. P. Ostrich - H. P. Stork P. V. Gr H. Bittern - H. P. Heron - 1 P. H. Grus pavonica - 1 P. H. Grus virgo - 1 V. 2 P. Curlew Ih. - - 1 P. 2 P. Gold-headed trum- peter 1 P. II. Flamingo . 1 P. 2 P. lb. - _ 1 P. C. Parra Jacana - H. 1 P. Grebe 1 P. VI. IS 2 P. Great Diver _ C. H. Apterodytes - 1 P. 2 P. Gull - . 1 P, 2 P. Petrel 1 P. 2 P. Swan 1 P. 2 P. Duck 1 P, 2 P. Rasores. 1 11. 2 H. Perrault. C. 1 H. 2 H. Perrault. 3 P. II. c. Duv. C. Cuvier. 2 P. 2 H. Duv. H. C. Perrault. 3 P. H. c. Meckel. H. Perrault. C. Meckel. Perrault. ALLATORES. C. Cuvier. c. Duv. 2 P. 3 P. c. Cuvier. 2 P. C. Duv. H. C. Perrault. II. c. Duv. II. C. Cuvier, Duv. C. 3 P. c. H. Cuvier. H. Meckel. 2 P. Cuvier. ATATORES. 3 P. H. C. Meckel. P. Duv. H. 3 P. Cuvier. H. 1 C. 2 C. Meckel. H. c. 3 P. Meckel. H. c. Cuvier. II. c. Duv. Siipp. a 98 PANCREAS. pancreatic secretion is tlie first poured into the intestines, and the c}’stic 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 jipenings 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 fluitls 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 p\lorus. while the pancreatic is three feet removed from it ; this is the greatest separation of thetwoilucts of any with which I am acquainted in the animal kingdom. It would present, if ostriches w'ere commoner birds, great facilities for ex- periment, and implies an action in both the secretions entirely independent and auto- cratic. JSIammalia. — The chief difFcrences 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 [leritoneum. 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 sup|)ressed, and must be con- sidered merely as an accessory portion. The various forms and arrangements of the pancreas do not a|)pear to have anything to do with its 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 Quadrumccua Fig. 74-. Pancreas n f the Rat (iiatural size'), shown hi/ throwhic/ up the duodenum, together with its proper mesentery, and the free process of peritoneum extending thence to the left, in which the gland ramifies. Its arborescent form and great extent are well shown. 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 pyloms. 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 by 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 wdth this, 'ormed a common duct analogous to the ductus tommunis choledochus. Tiedemann has de- ;ected a similar pancreatic reservoir in the ! * See the physiological portion of this article, ■age 104. 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 upwartls; and this arrangement, b_v 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 physiologj', — 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 jiarts, of certain material agents, the sum of whose common action gives as its result the func- tion of tlie 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. Physiolog3^ 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 wdde 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 w'as 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, finalii’, 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 frec]uent!y remote from the stomach. The second viev/, that the pancreatic duct admitted the chyle from the intestines, is assigned to Baccius and Folius, who both maintained that it * Hippocrates nowdiere mentions it. I De Humani Corporis Fabrica, i. 5. cap. 4. De Omen to. H 2 100 PANCREAS. served for the transit of tlie ch3'le from the intestine to the liver and s|)leen. \'erv early investigation, however, showeil 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//om it. The fourth ojunion is ascribed to Ves- lingius, who says, in speaking of the pan- creas*, Usus hujus cmifiHs ohscuriia non cst, nrnn cum aevem quendnm feUique non dissi- milcm succum cxhibcnl, pa/nin cut cxcrcmcnfum talc, per coctioncm ultcriorem a chylo separatum, aUici intra Iiunc at<]ue in duodenum intestinum cxpnrgarL This view, which is simply re- futed liy saying that the secretion obtained from the pancreas does not in any way reseml)le bile, that it is not “ felli non dissimilem,” was supported by Asellius, Riolanus, and others. J)e Graaf accounts for it by supposing that the tube introilncctl into the clnct for the juirpose of obtaining the secretion became covered with the bile accumulated about the common orifice ot the two ducts, which it might very well do, cither on being inserted or Withdrawn, and tlnit this, becoming mixed with the pancreatic secretion which it had witiulrawn, gave rise to the erroTteous opinion that that secretion had a resemblance to bile. The fourth opinion, that the pancreatic duct was the excretory canal of the spleen, which w'as maintained by Bartholini, is refuted by the simplest anatomical considerations, and was further disproved by De Graaf, wdio, to show its fallacy, extirpated the spleen of a dog, and, two months after the extir|)ation, obtained the pancreatic secretion unaltered. The fifth view was based on similar supposed anatomical relations between the jtancreatic duct and spleen. It is assigned to Lindanus, and was refutetl by the same considerations as tlie last. The theory that the pancreas carried off the excretion of the nerves was based on the old view that the nerves distilleil the animal humonrs and spirits. All these views are perha|)s rather amusing than in- teresting, aiul are among the curiosities of science. They show us how much our me- dical forefathers were tlisposed 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 nancreas furnished an iin[)ortant secretion of its own was first advocated by Franyois dele Boe Sylvius-)-, who first insisted on its acidity, and who at- tached great ini|'ortance to its pathological conditions. Iiuleed, he made its derangements tlie cause of neariy 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 tne interest which the lessons of ISdvius excited that De (fraaf, his pupil, undertook his admirable researches JJe Siicco Pancrea- t CO, and succeeded, in IG6'2, 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. * Symtagma Anatom, cap. 4. t Tiles. 37., De Usn Lienis et glandular. Vv'ith the view of obtaining the fluid, De Graaf fust 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 [lutting a stop to it. He then put a ligature round the duct at the point of its iinmergence 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 attemjit 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 flnid, but he could not obtain it in sufficient quantity to subject it to any ex- amination. With the view of obtaining some 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 liis 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, anti, attributing this to a certain admi.sture 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 pajier being rolled round it. Into the smaller extremity of this quill tube W'as 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, avid which passed through the quill into the flask anil out of the flask through the little hole. The object of the plug w'as to prevent the in- testinal contents from blocking up the quill and so obstructing the flow of the pancreatic secre- tion. Then (“ snblato ejulatu vicinis molesto, diiarum laryngis cartilaginura particulas cx- 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 PANCKEAS. 101 obviate the escape of the secretion through a second pancreatic duct, which, he sa3 s, 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 varying in taste, from salt to add, rough, acidulo-saline, orinsii)id. De Graaf’s memoir is well worth reading, and is, consiilering the time in which it was written, and in spite of the necessary admixture of a good deal of mediajval 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 Stivius, 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 ofWepferf, PechlinJ, Brunner^, and Bohn || 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. Viridet^ said that he found it acid in most animals, and pretended that it sen- sibly reddened litmus. Hauermann** * * §§, 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 J;j: 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- gendie found $5' th® jjancreatic juice in a dog to be yellowish, inodorous, and with a saline taste. He adds that the liquid is alkaline, * Tractatus pro Veteri Medicina. Lej’de. 1G70. t De Cicuta Aquatica, p. 200. I De Purgantiiim Medic. Facult. Leyde. 1672. § ExperimentaNova circa Pancreas. Amst. 1G83. II Circulus Anatomico-physioloaicus. Leipsier, 1710. 1 J o i 6> ^ De Prima Coctione, p. 26G. ** Physiologic, th. iii. p. 807. tt Versuche liber das Verdauungsgeschiift, Leip- sig, 1793. Joum. compl. et Diet, du Sc. Med. t.iii. p. 283. §§ Pr&is Elementaire de Plij'siologie, t. ii. p. 2G7. that it coagulates with heat, and that in birds it is altogether albuminous ; at least, that, e.x- 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 ado[)ted 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, “ Piura possunt esse officia liquoris non- dum satis noti and Magendie, fifty y ears 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 Las.saigne, 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 liejuid, with a slightly' salt taste, alkaline reaction, specific gravity' of P0026, 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, anil 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-crystalhzable 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 bad been exhausted by the alcohol was then heated with distilled water, when this latter show’ed on evaporation a certain viscosity, indicating the solution of an animal [irinciple in it. The result of the en- tire qualitative analyses, the further details of which I need not give, was as follows ; — 102 PANCREAS. Water - - - -99-1 Animal matter soluble in alcohol Animal matter soluble iu water Traces of albumen ■ - - -I 00-9 Tree soila . . . Chloride of sodium ('bloridc of ]iotassium Phosphate of lime Oxide of iron - - a trace 100-0 “ Not content,” say these observers, “ with this first experiment, we undertook a second with the same success *, aiul the results lur- nished by analyses were absolutely the same : from which we infer that the pancreatic juice jtossesses a perfect analogy with the saliva both of man anil the horse, these two litjuids containing absolutely tbe same fixed principles, nitrogenous and saline, and almost exactly the same quantity of water. f The attempts of these autliors 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 faded ; a few dro[)S were all they could procure. Their data, therefore, are all taken ifoin the secretion as they found it in the horse. Tiedemann ami 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 bitt sensibly saline taste, the first por- tion faintly acid, the [tortion 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 J 00-00 100 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 sotla) - - 18-44 Albumen, with a small quantity of salts .... 42-83 105-59 Exceeding - 5-59 * They do not say the quantity they obtained this time. I Loo. cit. p. 106. j Kecherches Exp^riinentales Physiologiques et Chiraiques sur la iJigestion. Jourdan’s transla- tion, p. 2-1. 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 (tiesiccated) 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 [irobably depended on the enfeeblement of the nervous influence resulting from the operation. f. 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 qiiantily of jjotash, 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 (salivarp) 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 contaii s 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 ; iu 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 he- 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, die. PANCREAS. 103 Very lately this subject has been taken up by several able physiologists, and Bernard* * * §, Frerichs -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 atid 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 very 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 di.stinct kinds, which he characterizes as normal and morbid; the for- mer 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 ;)ermanent pancreatic fistula ; the latter always secreted in great abundance when the symptoms of in- ffammatory reaction appear in the pancreas and in the wound in (he abdomen. The normal secretion, wdiich, 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 wdiite 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 coagulatetl by heat, alcohol, or the mineral acids. But, although exhibiting tlie same reactions, Ber- nard believes that this nitrogenous principle is essentiall}' 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 w hen it has been coagulated by alcohol and dried, it is easil}’ and entirely redissolved in water, whilst albumen, similarly treated, is not dissolved to any appreciable extent. J These characteristics of the fluid, which are given from the dog, Bernard says obtain equally in rabbits, hor.ses, and birds. The V’orbid pancreatic fluid, which is alone thrown out when the experiment is tardily or * Arch. GAi. de Med., 4th Ser. tom. 19. p. G8 — 86. t Wagner’s Handw’drterbuch der Physiol. I Die Verdauunggeschiit’t und der Stoftwechsel, Xeipsig, 1852. § Bernard believes this to be the active matter ;of the secretion, as it imparts to the water the pe- culiar viscosity and physiological properties of the pancreatic fluid. roughl}^ performed, and which always succeeds to the other wdten the experiment is happy, is watery, w ithout any viscosit}', 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 tliis, 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 analy.sis of this fluid*, and with whose ac- count Lehmann f 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 LOGO; heat, alcohol, and acid, produce but a slight turbi- dity; of solid constituents he found it contain but 1'3G per cent, in the ass, and L62 in the 1. Beijaud by aneurism of the aorta ; and M. Mondiere by scirrhous pylorus. In some cases it seems to be pro- duced by arrest of its function, as when scirrhous disease of the pylorus has put a stop to the passage of food into the duodenum. Dr. Wolf mentions a case in which the atrophy seems to have been produced by the ossifica- tion of the pancreatic arteries and obstruction of the duct. I do not know if there are any symptoms by which idiopathic atrophy de- clares itself during life, and in those cases in which it is secondary, the symptoms are those of the primary disease and not those of the pancreatic affection. The degree of wasting is sometimes very great ; Cruveilhier met with a case in which it did not exceed an ounce in weight. Induration. — Sometimes the pancreas is found of a firmer consistence than natural, without any perceptible alteration in structure. It has been alleged that in these cases it is the secreting structure that is affected, the areolar tissue not being implicated in the induration, which imparts to tlie gland a more nodular or granular appearance and feeling. But whether this is so, I cannot say, as I have never submitted an indurated pancreas to microscopical examination. It is said to be not uncommon for induration of this kind to disappear, as happenetl in a case recorded by Mr. Lawrence, soon after exposure to the air. Softening has been found to occur chiefl}' in persons suffering from scrofulous affections. Portal relates that he found the gland remark- ably softened without any other change, in two children who died of measels. In confluent small pox and malignant scarlet fever softening of the pancreas has occurred. Dr. Copland states that he has found it softened in cases of malignant remittent fever and scurvy, but only in conjunction with softening of other organs, as the spleen, &c. b. Inflammation. — The number of cases in which post-mortem appearances of acute in- flammation of the pancreas have been re- corded is certainly very small. When it does occur the appearances are said to be great injection of the whole gland, imparting to it a brown-red colour and an unnatural softness and friability. In a case recorded by Mr. Lawrence, this brown-red colour presented a strong contrast with the pale ansemiated con- dition of the other parts. When the inflam- mation does not end in resolution, it may give rise to the effusion of plastic lymph on the surface, producing a general or partial false capsule, or to the formation of pus in its sub- stance— pancreatic abscess. It is also said to end sometimes in gangrene. In consequence of the effusion and subse- . quent organisation of coagulable lymph upon the surface of the pancreas it has occasionally been covered by a false membrane of great consistence. By the extension of the ad- hesive inflammation to some of the neigh- bouring organs, as the stomach, duodenum, liver, spleen, mesentery, mesocolon, &c., bands are occasionally formed, connecting the pan- creas to one or more of these organs, which sometimes acquire so great a degree of hard- ness, as to be with difficulty divided with the scalpel. In suppurative inflammation, whatever may have been its point of commencement, the pus is ultimately infiltrated into the interlobular tissue, and when the process of suppuration is completed, is generally collected into one cavity. In most cases, the inflammation being but partial, this cavity is of moderate size ; but sometimes the suppuration proceeds to such an extent that the texture of the gland is almost entirely destroyed. In some in- stances, this destruction being complete, the purulent matter is contained in a membranous envelope, formed by the cellular tissue which covers the organ. Portal has seen more than two pounds of pus contained in a sac of this description. The character of the purulent matter in such cases seems to be various. According to Gendrin it is commonly inodor- ous and creamy ; Portal, on the other hand, states that in complete suppuration of the pancreas, the pus is sometimes of an intoler- able smell ; not unfrequently it is combined with a clear yellowdsh fluid, and with a whitish curdy substance, the most dependent part being occupied with a grey powdery pus. This has been attributed to its admixture with the pancreatic juice. In the great majority of case.s, inflammation appears to extend to the pancreas from neigh- bo'uring organs ; in some cases it becomes adherent to the stomach at a point wffiere the latter is undergoing perforative ulceration, and I have seen a case where this adhesion had a conservative effect and served as a stop- gap, whereby, when the ulcer had completely eaten through the coats of the stomach, the escape of its contents into the abdominal cavity was prevented. Portal speaks of ab- scess in the pancreas having been frequently observed in disease of the testicles, and men- tions one case in particular in which, after the extirpation of a testicle and the ligature of the spermatic cord, a large quantity of pus was found in the cord, and a considerable abscess surrounding the pancreas; and he refers to Antoine Petit as adducing different examples of this kind in support of his ob- jections to the practice of ligature. M. Ton- nelle mentions two cases of puerperal peri- tonitis in which pancreatic abscess occurred. In Mr. Lawrence’s case the patient died five weeks after delivery. It is to be regretted that in these cases more accurate dissections v/ere not made, particularly with the view of ascertaining the condition of the venous con- nexion between the parts primarily affected and the pancreas : it is very possible that the inferior mesenteric vein might have been found in a state of inflammation, and the pancreatic abscess might have been from secondary purulent deposit transmitted to if by branches from the s^ffcuic vein after the 110 PANCREAS. junction of the inferior mesenteric vein with it. The contents of a pancreatic abscess may be discharged in various directions. Some- times they escape into the cavity of the ab- domen; sometimes they pass into tlie stomach, and sometimes into tlie duplicature of the mesocolon, where they may he retained as in a sac, or, having perforated one of its laminae, m.iy be effused into the general cavity of the abdomen. It is supposed also that the pus of a pancreatic abscess may find its way into the intestinal canal, and be discharged by stool without any obvious communication being established between them. Tims, in a case communicated by Dr. Ilaygarth to Dr. Per- cival, in which, on dissection after death, the |)ancreas was found to contain a considerable abscess, blood and, at length, fetid pus had been discharged by stool during life. According to Dr. Pemberton*, ulceration is a very frequent result of inflammation of the pancreas ; and from the small degree of sensibility with which the organ is endowed,^ the destruction may go a great way without pain or any symptom previously existing which could lead to a suspicion that inflam- mation was going on. Portal alleges that gangrene of the pancreas is a frequent consequence of its inflammation, and that he has met with it in several in- stances. In one case, which he particularly specifies, the pancreas was found, on examina- tion, to be of a violet purple colour, softened, and allowing a blackish fetid humour to exude from its external surface. “ In short,” he says, “ it was gangrenous almost throughout its whole extent.” Gendriu quotes what he conceives to have been a case of gangrene of the pancreas, occurring after chronic inflam- mation, and suggests it as probable that in this, as in other tissues, acute inflamma- tion passes readily and completely into the state of sphacelus, only in cases in which the organ has been weakened by previous disease. c. lIcBmorrhage. — I have only met with two cases of haemorrhage in the pancreas : one recorded by Mr. Fearnsiile, in which the right extremity was occupied by a large coagulum ; the other related by Storck, in which the pancreas was so large aiul heavj' that it ex- ceeded thirteen pounds in weight. On cutting into this mass, it was found to consist merely of a sac filled with blood, partly grumous, partly coagulated, and beginning, it is stated, to become organised. d. Structural changes. 1. Non-mnlignarif ; cartilaginous transfurmation. — Many cases are on record in which the pancreas had been found cartilaginous ; it is generally enlarged, nodular on the surface, and very hard. In the majority of cases, one or more neighbouring organs have been found similarly affected ; but in some rare cases the pancreas has been the exclusive seat of the cartilaginous de- generation. In persons aflected with it * On Diseases of the Viscera, p. G3. et seq. nausea, vomiting, thirst, pain in the epi- gastrium, &c., had existed, and it was pro- bably the remote consequence of chronic inflammation. Stcatomatous concretions. — Portal states that the pancreas is sometimes found full of steatomatous concretions, hard or softened, white like suet, or yellowish like honey. Sometimes the pancreas is enlarged by this matter throughout its whole substance, some- times it exists only in particular parts. Those who have died of scrofula, and in whom the glands of the neck, axillm, groins, or me- sentery were obstructed, had likewise the pan- creas equally affected. He mentions a par- ticular case in which the mesenteric glands were full of steatomatous concretions', and in which the pancreas, besides being enor- mously enlarged and full of similar concre- tions, was covered by one of the consistence of suet and more than five or six lines in thickness. In this case the surrounding cel- lular texture, the mesocolon, and the parietes of the stomach, were cartilaginous and thick- ened, in consequence, he supposes, of the pressure of the tumour. He states, however, that the pancreas has been found affecteil when no marks of scrofula were observable in any other part of the body. Meckel staten that he has seen the organ changed to an almost tophaceous mass. The steatomatous concretion of Portal seems to be identical with the tubercle of the present day ; and accordingly, both in the human subject and in the lower animals, tu- bercles of the pancreas have been occasionally met with, particularly in cases in which the lungs had undergone a similar degeneration. M. Lombard states that of one hundred cases of tuberculous disease in children which he examined, he found, in five, tubercles exist- ing in the pancreas.* Cystic tumours; hydatids. — These are of rare occurrence. M. Becourt has described a preparation in the Museum of the Medical School at Strasburg, of a cyst of very large size in the body of the viscus. Dr. Gross has given the following description of one, in a communication to the Medical Society of Boston. f On opening the body, a voluminous fluctuating tumour of oval form was found situated beneath the right lobe of the liver, with which it had conti'acted intimate atl- hesions. It was placed between the intestines and the jiosterior abdominal wall, passed a little to the lelt of the vertebral column, and had in front of it the curvature of the duo- denum. It contained from 10 to l-I ounces of a sero-sanguinolent fluid without clot, slightly viscid, and without any ajipearancc of fatty matter. There was not a trace in its walls of any of the normal tissue of the pancreas, although it was evidently formed by that organ. It contained some very small calculi, resembling those ordinarily met within the ramifications of the pancreatic duct, and two of these, from three to four lines in dia- * Lilirary of Medicine, vol. iv. f Archiv. Gen. de Med. iv. serie, t. 218. PANCREAS. Ill meter and rough on their surface, completely obliterated the opening of the pancreatic canal into the duodenum ; they were composed of carbonate of lime. The rest of the pancreas — that is to say its left extremity — was about two inches long and very hard : the imncreatic canal of this •portion of the gland opened into the cavity of the cyst. This circumstance, and the fact that that portion of the duct leading from the cyst to the duodenum was blocked up by the calculi, make it exceedingly probable that the cyst w'as primarily nothing but a dilatation of the duct in consequence of this obstruction. It is possible that this may be the origin of most of these cysts, and much to be regretted that the fluid contained in them has not been submitted to a rigorous examination, with the view of ascertaining whether it has any analogy to the secretion, or admixture with it. Two cases of reten- tion of the pancreatic fluitl recorded by Cru- veilhier, confirm the probability of this sup- position. “ The dilated canal resembled a transparent cyst ; the contained fluid was extremely viscid and clear, but of a whitish hue like a solution of gum arabic ; it had a slightly saline taste; the collateral ducts were extremely dilated. There were some white patches, resembling plaster, in the centre of many of the lobules. This substance was more abundant in some of the lobules, and, when removed, presented the appearance of small lumps of plaster or chalk.” These creta- ceous lumps might have been of the nature of pancreatic calculus, which we have already seen associated with a cyst involving the duct, or the earthy remains of old tubercle. Fatty degeneration. — I have frequently met with fatty degeneration of the pancreas, and all the instances in which I have detected it have been cases of diabetes. After finding it in four successive cases of this disease, I fancied that I had hit upon its cause and the secret of its true pathology. Although it seemed rather a “ lucus a non lucendo ” argument to at- tribute an undue formation of sugar to the de- rangement of a sugar-forming organ, yet in a class of bodies so full of instances of isomerism as the starch and sugar series, it appeared to me possible that an imperfect or depraved pancreatic secretion might give rise to the formation of an imperfect glucose incapable of those after changes by which it is worked out of the circulation. The meeting, hov/- ever, with other cases of diabetes in which the pancreas was not fatty, and, still more, the perusal of M. Bernard’s observations with re- gard to the part that the liver plays in the formation of sugar, and the disease of diabetes, dispelled my theory, and compelled me to re- gard the fatty state of the pancreas as the consequence, and not the cause, of the diseased condition, undergoing this degeneration in common with other organs ; for I never found fat in the pancreas without finding it in enor- mous quantity in the liver and kidney. I may here remark, that I have not been able to confirm Dr. Johnson’s observation*, that in * Diseases of the Kidney, p. 395. diabetes, when the kidney cells contain a large quantity of oil, the hepatic cells contain an unusually small amount, and have a “ starved ” appearance ; for I have invariably found the accumulation of fat in the liver and kidney cells, in cases of diabetes, in direct, and not in inverse, proportion. The microscopical appearances of fatty pan- creas are of two kinds, depending, I think, upon the length of time the degeneration has existed, and the amount of fat (fig. 75.). In one, the amount of fat is small, the globules very minute, confined to distinct epithelium cells. Fig. 75. A. The process here is but slightly advanced, the oil-globules small, and the epithelium distinct, par- ticularly where some cells have escaped, as at b ; at a, too, wdthin the follicles, they are visible. B, another specimen, in which the fat was more abundant, and the destruction of the tissue com- plete. and giving them, from the increased opacity it imparts to them, a more definite individuality (A. o.) ; in such a case, if a follicle is ruptured the epithelium escapes, each cell containing its own minute fat globules (A. B ), and the amount of free fat, if any, is very small. In the other case, the appearance of individual epithelium cells in the follicle is altogether lost, the fat globules are larger and mote nu- merous, and the rest of the contents indis- tinctly granular. (B. «.) Sometimes the oil globules completely fill the follicle; when in such a case pressure is apfilied, and the follicle contents forced out, no distinct epithelial cells are seen floating about, but all that is not fatty is amorphous and broken down. (B, b.) * 2. Malignant. — Scirrhus and carcinoma. — These appear to be among -the commonest af- fections of the pancreas. The disease gene- rally affects, or commences in, a part only of the organ ; and appears to be primarly pan- creatic, for in some cases the jiancreas alone has been found affected. Dr. Bigsby enume- 112 PANCIIEAS, rates twent3'-eight cases in which the disease appeared to be idio[)athic, and in eiglit, wliicli were of long standing, did not extend bej'ond the pancreas; more fre(|iientlj’, however, it implicates neighbouring parts in some degree, particularly the duodenum, stomach, and [ly- lorus. It ma}' exist without any increase of size, but more frequently is attended by some enlargement, which may be considerable. Scir- rhus rarely goes on to ulceration, the asso- ciated lesions terminating fatally before that time. It often gives rise to constriction of the bile-duct anil deep jaundice, and even com- j'ression of the aorta : this compression and constriction of the aorta have been known to occasion aneurismal dilatation above the seat of the constriction, as seen by Portal and Sal made. Of the twenty-eight cases analysed by Dr. Bigsby, in seventeen the disease had not ar- rived at the stage of softening, although some of them had existed for years ; it was purely scirrhus. In five cases he states the scin hus had, at the time of death, passed into the soft state called ccphaluma by Dr. Carsw’ell, and medullary sarcoma by previous writers. Some jtarts, however, were as hard as cartilage ; but others had all the [uilpy, pale yellow, brain- like character of the second stage of scirrhus. In one case, the pancreas was changed into a sac, with a few shreds of cephaloma here and there on its sides. Lastly, in two cases no vestige of any form of scirrhus remained, the gland being altogether in a state of cancerous ulceration. Fungo-hcematoid disease has been found in the pancreas in three cases by Dr. Aber- crombie, and in single instances by Dr. Bright and others. Dr. Copland found this lesion in the pancreas of a boy fourteen years of age ; several other organs were also affectedby it.* e. Calculous concrelio)is in the pancreatic duct and its branches are by no means uncommon, and appear not unfrequently to be the cause of some of those morbid changes that have been already noticed. Sometimes they are manifestly in the duct ; at others, though [iro- tably primarily so, they appear, from oblite- ration of the duct in which they were lodged, o be in the gland substance. They are usu- illy white, but occasionally black ; they vary much in shape, being sometimes round, and sometimes irregular ; their size ranges from that of a pea to that of a small walnut, and their number from one to twenty ; sometimes they are scattered throughout the gland, sometimes aggregated in a mass. Gendrin mentions that the pancreatic duct is some- times clogged, not with distinct concretions, but with a chalky powder. In respect to chemical composition it seems probable that |)ancrcatic calculi are liable to some varia- tions. Dr. Pemberton -{- mentions having re- ceived one from Dr. Baillie from the human pancreas which consisted entirely of carbonate of lime ; whereas, one from the ox analysed by Dr. Wollaston turned out to be phosphate of * liledical Diet. Loc. oit. t On the Viscera, ii. GS. lime. Portal mentions that in a case in which he met with a dozen of light, round, wdiitish calculi in the pancreas, he found that when he reduced one or two to coarse [)owder, and threw this into boiling water, it readily dissolved ; and Fonreroy states, as the result of his examinations, that pancreatic concre- tions are composed of phosphate of lime com- bined with some animal matter, just as is the case with salivary calculi. There is one circumstance connected with the morbid anatomy of the pancreas worthy of special note, aiul with a short reference to this I shall finish this paper ; it is Fhc occurrence of Jalty stools in connection with pancreatic disease. Attention was first drawn to this subject twenty' years ago by the simultaneous |)ublication, in the eigh- teenth volume of the Medico-Chirurgical Transactions, of pa[)ers by Drs. Bright and Elliotson and Mr. Lloyd ; but although the subject excited considerable interest at the time, it has since been suffered to lapse, from want apparently of due appreciation of its import ; and it is only recently that it has emerged from its obscurity in consequence of the new interest with which recent physio- logical discoveries have invested it. It is only the most hasty and superficial glance that it will be possible here to give to this most interesting subject : for further details I must refer the reader to the original papers, to others that have since been published, and to an admirable article in the twenty-third number of the British and Foreign Medico- Chirurgical Review. The first of these papers — first as much in importance as in time — was that of Dr. Bright. Not only was he the first to point out the pathological relations of this remarkable phenomenon, but his paper is distinguished by a singular clearness and impartiality, and by a thorough digestion of its carefully ga- thered materials. He thus describes the pe- culiar condition of the evacuations that first excited his attention : — “ A portion more or less considerable assumes the character of an oily substance resembling fat, which either passes separately from the bowels, or soon divides itself from the general mass, and lies upon the surface, sometimes forming a thick crust, particularly about the edges of the vessel, if the fasces are of a semifluid con- sistence ; sometimes floating like globules of tallow which have melted and become cold ; and sometimes assuming the form of a thin fatty pellicle over the whole, or over the more fluid parts in wdiich the more solid figured faeces are deposited. This oily matter has'' generally a slight yellow tinge, and a most;" disgustingly feetid odour.” After detailing the cases. Dr. Bright insti-. tutes the following analysis of them : — “ In all of these, chronic ailments terminated, soonc or later, in jaundice ; and in all of them a great peculiarity in the character of the dejec- tions existed. In the result of the examina- tion after death we have likewise some cir- cumstances w'hich coincide in all — obsirucied PAJJCREAS. Ii3 biliary ducts; the liver gorged with bile; fungoid disease attacking the head of the pancreas ; and malignant idceration on the surface of the duodenum. The question to be solved is, upon which of the conditions indicated or caused by these morbid changes, if upon either, the peculiarity of the alvine evacu- ations depended ? That tlie obstruction of tile biliary ducts, or even the total absence of all indication of biliary secretion, is not usually attended by the same peculiarity in the eva- cuations, many cases which have been cau- tiously detailed by various authors, and many which we have all observed, bear sufficient testimony ; and I was therefore induced to ascribe it, either to the existence of malig- nant disease, or to that disease being situated in the pancreas. That the simple fact of malignant disease existing is not necessarily productive of such appearances in the faacu- lent matter, I infer from cases both of that form of disease and of melanosis in the liver to a very great extent being, within the scope of my experience, unaccompanied by any such discharge, though the evacuations were sub- mitted to the most rigid observation. That simple ulceration in the bowels to any known extent, is not attended by any such symptom I am led to believe from knowing that neither in the most extensive ulceration of the large intestines in cases of dysentery, nor in the worst cases of ulceration of the small intes- tines in fever, in diarrhoea, or in phthisis, does anything of the kind occur. Whether, how- ever, malignant ulceration of the mucous membrane is .accompanied by this symptom I cannot assert, though I have often seen most extensive ulcers of the pylorus and of the rectum, where, although the evacuations were attentively observed, such fatty matter was not detected. As, however, a malignant ulceration of membrane did exist in each of the foregoing cases, it is not impossible that this was the cause of this symptom ; but we must bear in mind that such ulcerations are by no means uncommon, and that the pheno- menon of which I am speaking is uncommon ; and that in each of the cases it was accom- panied by another morbid appearance, which is not common; namely, the malignant disease of the pancreas. The fact of the intestinal ulceration having in each case occupied the duodenum does, however, somewhat diminish the weight of this observation, for that cer- tainly is not so frequent an occurrence.” By this process of elinjination, and by the in- s'^ance of other cases more or less analogous, Dr. Bright conceives that we may bring the circumstances of the diseased structure in connection with this sjmptom within a nar- row limit — “ disease, probably malignant, of that part of the pancreas irhich is near the duodenum; and ulceration of the duodenum itselfP To this conclusion, however, so care- fully arrived at, subsequent observation has shown that exception must be taken : cases that have occurred since the publication of Dr. Bright’s paper, and even quite recently, have proved that neither the malignant cha- Supp. racter of the disease nor ulceration of the duodenum is necessary to the production of the fatty stools. In a case in which fatty stools occurred, communicated to the Society of jNIedifine of Boston *, in one reported by Dr. Alfred Clarke, of Twickenham, in the Lancet for r^ugust 16. 1851, and in one re- ferred to by Dr. Kirkes in his Handbook of Physiology -j-, the pancreatic disease appears to have been clearly non-malignant, and to have consisted in the conversion of the organ into a serous cyst in consequence of obstruc- tion of its duct; and the duodenum seems to have been quite health}'. In two, however, of these cases, there was jaundice, and in the third deficient bile in the evacuations, so that the pancreatic disease was not p7ire. What we want for the clearing up of this subject as far as the pancreas is concerned is, a case in which the pancreas alone is affected, other organs not being even functionally implicated, and in which there is during life a clear pre- sence, or a clear absence of fatty stools. Until such a case or cases can be brought forward, the light which this section of pathology has thrown upon j)hysiology will still leave unde- termined the relative importance, in effecting the absor|)tion of fat, of the different digest- ing agents supplied by or poured into the duodenum. Bibliogkapiiy. — ce. Descriptive. — TTirsun;;, Figura Ductus cujusdam, &c. I’ad. 1G-J3. Wharton, Adenographia, Lond., 1G50. Hoffman, De Pancreate, Altdorf, 1706. Sa;mmerring, Corp. Iluniaii. Fab. Lond., 1754, t. ■\d. Santorini, Tabulie seirteii- deeim ; Parma, 1775. Hlarjolin, jManuel d’Anatomie, Paris, 1815. 3Iecket, iManuel d’Anatoniie, Paris, 1825. Siehold. Cruveilhier, Anatomie Descriptive. iJorrfeu, Reclierches rVnatomiques sur la Position des Glandes, et sur leur Action. Ticdeinann, Sur les Difierences que le Canal Excre'teur du Pancreas, &c.. Jour. Compl. des Sc. Med., t. iv. p. 370. Quain and Sharppffs Anatomy. Ticdemann s Plates, and the various text-books of Descriptive Anatomy. /3. Microscopical structure. — 3Ialpighi, De Yis- cerum Structura. Ruysch, Op. om., t. iii. MiWer, Physiology, by Bah'. Idem. De Glandular. Secer- nentium Struct. Penit., Lipsia;, 1830. Gerber, Ge- neral and Minute Anatomy. Berres, Anatomica iMicroscopica Corp. Hum. Nicolucci, Sail’ liitima Struttura della Glandula Paucrea, im Filiatre Se- bezio Maggio, 1847. Jones, Wharton, in Phil., Trans., 1848. Vernenit, Anatomie du Pancreas, Gaz. Med., 1851. Heyfeider, Acad, des Sciences, Juiu, 1852. Bernard, (la Wq Structure and Func- tion of Glands, Acad, des Sciences, 1852. Knox, in Med. Gazette. y. Comparative Anatomy. — Blumen1>ach, Bfanual of Comparative Anatomy, by Coulsou. Cuvier, Lc(jons d’Anat. Coni’p., t. iv. Ticdemann, Sur les Ditfereuces, &c.. Journal Comp, des Sciences Med., t. iv. Grant, Lectures on Comparative Anatomy, Lancet, 1833-4. Wagner, Elements of Comparative Anatomy, Trans, by Tulk. Ou-en, Comp. Anat. vol. i. and ii. Jones {Bi/mer), Comparative Ana- tomy. Sta7inius, IMutter's Archiv. 1849. S. Physiology Brunner, Experimenta Nova circa Pancreas, Am.st., 1G38. Sylvius, Thes. 37. De Usu Lienis et Glandularum. Graaf, Begner, De Succi I’ancreatici Natura et Usu, Lugd. Bat., 1671. Johrenius, De Affect. Hypochond., Kinteln, 1678. Wharton, Adenographia. IliiHer, Physiology, by * Archiv. Gen. de Mc'd. t. xix. p. 215. t P. 233. I 114 PELVIS. lialv. Gondsir, The Ultimate Secretincf Structure au(l the Laws of its Function, Trans, lloy. Soc. of Filinb., vol. xv. Cyclopaedia of Anatomy, Articles T^inf rill ftnc. ATr*(i- Secretion and Digestion. Meyer, Diet, du Soc. I\It'd. t. iii. p. 28.9. Furdyce, A Treatise on the Digestion of Food. Blumeubach, Institut. of I’liysiol. Lenret and Lassaigne, Recherches e.xperimentales sur la Digestion. Tiedemanti and Gmelin, Recherches Physiologiques et Chimi((ucs pour servir a ITIis- toirc de la Digestion. Bouchardat and Sandras. Chemistry of Digestion. Bernard, De FOrigine du Sucre, &c.. Arch. Gen. de INIed., 1848 Idem., Du Sue. Pancreatique, &c.. Arch. Gen. de ^Icd., 1810. Bidder nnd Schmidt, Die Verdanungsgeschafte nnd^der Stoffwechsel, Leipsig, 18j2. Lenz, De Adipis Con- coctione et .Vbsorptione, Dorpati, IS.oO. Bohin et Vcrdcil, Traite de Chimie Anatomique et I’liysio- logiquo, Paris, 185,9. Frerichs, Wagner’s Iland- wbrterbuch der Physiologic, vol. iv. Colin, Comptes Kendus. c. Jlorbid Anatomy. — /(/or<7U9H/, Dc Causis et Seilibus Morborum, Fpist. x.xx,. Ai t. 8. 9. 1 1. 13. Briald, Elliotson, and Lloyd, Aled. Chir. Trans., vol.' xviii. Critveilhier, Anat. Pathologiqiie. Baily,^ iMorbid Anatomy, chap. xii. PemherUm, Diseases ot the Abtlom. V’iscera. Fcarnside, Med. Gaz., vol. xlvi. Mondiere, Archiv. Gen. dc MeU, t. xii. Battershy {Dr.), Dulilin tiuartcrly .lourn., vol. xxiv. Monthly Journal of iMed. Sc., Sept., 1818. Ahercromhie, Med. Chir. Trans., vol. xviii. Thompson, Library of Medicine, vol. iv. Lawrence, Hied. Chir. Frans., vol. xvi. Copland, Meil. Diet., Article “ Pancreas.” Gross, Archiv. Gen. de Me'd,, t. xix. Kirhes, Handbook of Phy.siology. Clarke {L>r. Alfred), Lancet, Aug. 1851. ( Hyde Sailer.) PELVIS. (tteXu;, Gr. ; Pelvis, Lat. ; le Btsshi, Fr.; das Bccken, Germ.) — The pel- vis is tlic bony girdle wliicli connects the spinal column vvith the bones of the lower or hiiuler extremities. It derives its name from its supposeil resemblance in the human subject to a basin. Its figure, however, varies greatly in dift'erent animals. The description which follows, refers to the human male pelvis, which may be taken as a standard cf com- ]iarison. It is composed of three [irincipal pieces, two of which are symmetrical in shape, lateral in position, connected an- teriorly, and called the innominate bones ; and the third, callerl the sacrum, intervenes between the former at their posterior extre- mities, and connects them tothe spinal column, of which it forms the inferior or po.sterior portion. Ap[)ended to the lower extremity of the sacrum is a small bone, the coccy.v, — the representative of the caudal bones in the lower animals, — which, as influencing the shape and completing the formaiion of the walls of the pelvis, is considered as a part of it. The Innominate Bone (0« innnminatum, co.ranim, sive pelvis lateralis, Lat ; lOs d'ile, c>xau.v,¥w, das ungenannte Bein, Germ.; — - figs. 76, 77.) is a bone of so irregular a ■sliape as to leave it without a name in the fan- ciful nomenclature of the older anatomists. It is broatl and expanded at the upper ex- tremity, rounded and perforated at the lower, constricted in the middle like a figure of 8, and bent into a curve, with its concavity di- rected forwards, tipward.s, and inwards, at tlie tipper end ; and backwards and inwards at the lower, so as to form a segment of the pelvic circle. Its office is to support the bones of the lower extremities; to transmit to them from the sacrum the weight of the trunk in the erect position ; and to afford a basis of sup- port in the sitting posture. It also forms a [irotccting enclosure to the important viscera within it, anil gives attachment to the abdo- minal and leg muscles. This bone is usually described in three separate portions, into which it is separable in young persons, and which are called, re- spectively, the haunch bone or ilium (das H'ufL bein. Germ.; I’ Ileon, Fr.); the seat bone or ischium (to wxiov, Gr. ; das Sdzbein, Germ. ; I' Ischcon, Fr.) ; and the share bone or pidhs (6 KTtiQ, Gr. ; das Schaambein or Schoossbein, Germ .}. Of these three, the ilium forms the tipper expanded portion, and the pubes and ischium the lower perforated portion; the former being placed before, and the latter behind the opening. In the perfect bone, however, these three are completely soldered together by bony union in the central constricted portion, w here each con- tributes to form a deep cavity, externally, for the reel ption of the head of the thigh bone. From this cavit}' the three portions radiate ; the ilium u[)wards, the ischium downwards, and the pubes forwards, each contributing to support the thighbone by its central extremity. The imiomiiiate bone may, however, be most briefly described as one bone, consisting of two surfaces, external and internal ; bounded by lour borders, sujierior, inferior, anterior, and posterior. The superior border, formed entirely by the ilium, is the most regular and the most ex- tended. It forms an arch, directed from be- hind forwards and outwards, and curved laterally so as to jiresent, on looking at it from above, the shape of an italic f; the smaller concavity being posterior and directed outwards ; and the larger, anterior and di- rected inw'ards, contributing to form the ge- neral concavity of the internal surface. This border is thickened in a somewhat irregular manner, forming what is called the crest of the ilium (a,c,b), upon which may be traced an internal and an external lip, and a rough bread central line. These ridges are caused by the attachment of the abdominal muscles. The external lip is called, by some authors, the su- perior curved line of the ilium. The crest is very much thickened ami irregular at the pos- terior extremity, wht re it terminates in a hack- war .1 projection, the posterior superior .spinous process (b ). It is also thickened into an out- ward projection a httle in front of the centre (c), and also in a less degree at the anterior extremity, w here it projects forwards, forming the anterior superior spinous process (a). The anterior border consists of an upper vertical portion formed by the ilium, and a lower oblique portion formed by the pubis. It commences above at the anterior superior spine, an inch below which it presents a similar if' PELVIS. 115 projection called the anterior inferior spinous pro- cess (d), the two being separated by a snio )thly edged notch {it). Below the inferior spine is another indentation, wider and less deeply marked, and forming part of the overhanging edge of the cavity for the thigh bone, and in which a muscle lies. To this succeeds be- low, another rounded, less strongly marked prominence, in which the ilium and pubes are united, called the lUo-pcctineal eminence {e). From this point commences the ob- lique or inward direction of this border, which is for about two inches smooth and rounded for a muscle to glide over, and then presents a fourth well marked, acute, forward projection called the spine of the pubis (/), which is continued by a rough strongly marked ridge, the crest of the ]nrolonged at their further extremities into battened tapering processes, which, alter- ing the original direction of their respective portions of bone, one ascends oliliquely in- wards, and the other descends obliquely out- wards, to unite with each other midway, at a point i.narked by a slight transverse line. They are named respectively the ascending ramus of the ischium (r), and the descending ramus of the pubis (-i).* Together they form the inferior border of the innominate bone, and complete the formation of a large oval opening, situated immediately below, and a little internal to the coryloid cavity, having its long axis directed obliquely downwards and outwards, and called the obturator or thyroid foramen (o) — Sivpeoc, a shield ; and o’ooe, like. The edges of tliis opening are thin, bevilled off, and rough, for the attachment of a fitscial ligament which closes the opening, and are fonned entirely by the ischium and pubes. The external edge, instead of meeting the internal superiorly, is continued inwards in front of it, along the superior ramus to the spine of the pubes before described, forming a prominent rib of bone of a triangular shape (r/), its base abut- ting on the cotyloid cavity. This rib is con- vex vertically, and concave laterally. Between it and the internal edge of the thyroid fora- men is left a groove, called the sub-pubic or obturator groove (t), for the passage of a nerve and vessels, and which has a direction down- wards and inwards. The junction of the horizontal and descending rami of the pubis is called the angle of the 2>ubis, and it is hol- * There has been much confu.sion in the applica- tion of names to these bones, tlie term body of the pubis is applied hy .some to the angle, and by others to the cotyloid portion only. The term body ia confined also by some to the acetabular part of the ischium. The expressions horizontal and descending rami of the pubis and ascending ramus of the iscliium were applied before a true knowledge of the pelvic obliquity' was obtained. The former would probably be well superseded by the words superior and inferior, anil those applied to the ischial rami by anterior and posterior, or greater and lesser . PELVIS. 117 lowed, roiigli, and broad in front, for the attacliinent of some muscles of the leg. There are numerous nutritious openings on this sur- face of the ischium and pubis, which are chiefly directed towards the cotjloid cavity. Ftg. 77. Internal vieio of the os imwminatum. The internal or feloic surface presents for examin.ition a superior or iliac portion di- rected forwards, upwards, and inwards, and an inferior ischio-pubic portion directed in- wards and backw'ards. The iliac portion is rough at the posterior third, and is marked b}' a thick, massy, ii re- gular prominence, just below the posterior extremity of the crest, wliich is continued to the jiosterior superior spine, and serves for the attachment of powerful ligaments which connect this bone to the sacrum. This may be called, for brevity, the iliac tuberosity (1). An inch and a half below this is an angu- lar or semilunar articular suiface, the sacral, or auricular {2), to which the sacrum is at- tached in the complete pelvis. This surface is generally more or less rough and irre- gular, for the more firm attachment of the articular cartilage. It is com])osed of two elongated portions placed at right angles to each other, of which the inferior is the longer, and is directed horizontally backwards to the posterior inferior spine, parallel with and close above the upper boundary of the great sciatic notch (m, n), while the superior is directed vertically upw'ards towards the crest of the ilium, to which its raised anterior border is prolonged by a well marked ridge (3). At the angle of junction of these two limbs is gene- rally to be seen a deep hollow, while the ex- tremity of the inferior limb is bevelled off to correspond to elevations on the opposed sur- faces of the sacrum. In the retiring angle formed by the auricular surface is a very rough depression for the attachment of inter- osseous ligaments (7). The anterior two thirds of the internal iliac surface forms a complete smooth and regular hollow called the internal iliac fossa (d') for the reception of a muscle, which is continued downwards and forwards into the groove before described, below the anterior in ferior spine of the ilium (rf to with its long diameter half an inch in extent, and directed transversely. To it is articulated the base of the coccyx. . The anterior or ])elvic surface is smooth and directed forwards and downwards, form- ing the posterior wall of the true pelvis. It is widest above, o|)])osite the lateral masses of the base (c). A little below this point it is about three-fourths of an inch nar- rower (/;). 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, wliere 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 siile of the median line are four holes, the anterior sacral foramina, st'[)arated from each other by three rounded transverse 2>rocesses 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. Fiach 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 (b). 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 uj>per transverse tubercles of the coccyx. There are many ojienings for nutritive arteries in this surface, directed generally towards the centre of the bone. The 2^osterior surface {fig. is) 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 [)lace 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 fi*'st 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 vertebras of which the sacrum is com- The last of tliese, ami sometimes the two lower posed, the whole being called the sacral crest, are divided by a notch ( lOj, which opens u Fig. 78. A, anterior surface and base of sacrum ; B, lateral and posterior view of the same hone; 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 laminse, 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 vertebrae. 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 ti()s of the transverse processes of the vertebrae. The highest of these are sometimes smoothetl into a facet externally (8), by impinging upon the iliac tuberosity, and the fourth (9)- is al- waj's 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 lateral surfaces of the sacrum (fig. b) are broad above, and taper gradually downwards. When opposite the tw'o last sacral vertebras, 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 tlie 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 tiie 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 sphial caiial, 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 laminte, spines, and articular processes are, however, chiefly composed of dense bone, I 4 120 PELVIS. The Cuccvx (fig. c), the huclclc, or ivliistle bone (named from its suj)posed resemblance to a cuckoo’s hill, from kokicv^, (Jr. ; Os coccygk, Lat. ; I'Os coccyx, Fr. ; das Slcisshcin, or Schwanzbcin, (icnn.), is an appendage to tlie apex of the sacrum, and terminates the spinal column inferiorly. It forms tlie posterior boundary of the lower part of the cavity, ami inferior outlet of the ]ielvis, a.ssisting to complete its walls, to sustain its contents, and to attach some muscles of the leg iind 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, rai'ely five pieces or tu- bercles, which are generally, luit not always, soklereil to each other, and dimiTiished in size and completeness downw'ards. When in one piece, it ju'esents a ta[)ering, elongated, knob- beil appctirancc- with an anterior anil posterior surface, tv\ o lateral borders, ami a base ami nj)ex. The base presents a plane, oval, arti- cular surface (a), corresponding to the a|)ex of the sacrum, with which it is articulated, and sometimes ankyloseil. Behind this, on each side, projects upwards and backwards a cornuated |)rocess (b), tipped with an ellip- tical articular facet, directed upwards and forwards, to articidate with the inferior sacral horns. Below these, the borders commence, presenting three alternate notches (e), and tubercular projections (c), of which the first arc much the large.'-t, ami complete the sacro- coccygeal foramina. The borders are ter- minated by a knobbed, sometimes bifurcated apex, and give attachment to the sciatic liga- ments, and some muscles (d). The first two of these notches are converted into holes by ligaments, for the passage of the posterior branches of the fifth and sixth sacral nerves. The anterior surface is slightly concave longi- tudinally, and smooth, to su|)port the rectum. It has transverse markings, similar to the sacrum. The posterior surj'acc is cori’espond- inuly converse and rough, to attach ligaments and muscles. The internal structure of this bone closely resembles that of the sacrum. Devei.oi'ement. — The innominate hone is developed by three primitive and five com- plementary points of ossification. The three primitive points commence in the three component parts of the bone, the ilium, ischium, and pubis respectively, from a •single piece of cartilage of the general form of the bone. That of the iliimi is placed in the thick, arched rib above the cotyloid cavity, (./?g. 79. A, r/), being apparent, according to (fh uveilhier, the first in order, about the fiftieth day of foetal life. Bischoff, however, sa3's that the time of its appearance varies from the second to the fourth month, in dif- ferent individuals. About the fifth month, it acquires somewhat of the form of the coin- j)lete boue. That of the ischium is placed in the upper part of the descending ramus (b), and appears second in order of time, always later than the ilium, about the end of the third mouth, or, according to Bisclioff, the fifth month. That of the pubis appears in the superior branch, near the ilio-pectineal eminence (c), at the end of the fifth month. Bischoff fixes it later than Cruveilhier, at the sixth or seventh month. At the period of birth, the cotyloid cavity is still principally cartilaginous (e), the ascending branch of the ischium, the descending of the pubis, and nearly the whole circumference of the ilium, still remaining in the same condition (rf). At the age of six or seven years, the branches of the ischium and pubis are united by bone. About the time of puberty, as first pointed out by M. ISerres, a distinct complementary point of ossification appears in the cartilage dividing the bones in the cotyloid cavity, which soon including the whole of the Y- shaped cartilage at this part, and assuming its shape and serrated margins, finally unites them in the raised line before described. According to Meckel, the pubis and ischium join first with each other, and the ilium becomes united to them afterw'ards. At the same time appear the four remaining com- plementary points as epiphyses, in the fol- lowing order: namely, 1. ()n the whole length of the iliac crest ; 2. At the anterior inferior spine, not constant, and said to be more fre- quent in the male than the female ; 3. Along the whole extent of the tuberosity of the ischium ; ■f. On the symphysial surface of the pubis, said by Bedard to be more often found in the female. All these are soldered to the bone, about the twenty-fourth or twenty-fifth year, the epiphysis of the iliac crest being the last to join. Fig. 79. A 15 Development of the hones of the human pelvis, (After Qiiain and Sharpey.') A. Innominate bone of a full-growm foetns ; a, primary ossific point of ilium ; h, do. of ischium ; c, do. of pubis ; d, d, cartilage ; e, Y -shaped cen- tral cartilage. n, sacrum and coccyx at birth ; a, central ossific points ; b, characteristic sacral do. ; c, coccyx still cartilaginous. The sacrum is produced by the soldering together of five vertebree. Hence they have been called the false or sacral vertebra. Oc- casionally six pieces liave been found, and, more rarely, according to Scemmerring, four pieces only are present. Each of tliese five pieces, as in the other vertebra?, results froin three primary points of ossification, viz., one for each body or central portion, and two for tlie posterior latei'al surfaces ami laminae of each vertebra. These ajipcar later PELVIS. than in the true vertebrae, and are first ma- nifest in the bodies of the three upper {fig. B, a), at the second or third month of fcEtal life, and in the two lower at the fourth or fifth month. The lateral points are de- veloped between the sixth and ninth fetal months, and are united to the bodies (each after joining with its fellow opposite at the spinous tubercle) at from the second to the sixth years of age, beginning, according to Quain and Sharpey, at the lowest or fifth ver- tebra, and going vjjwards. Besides these, there are two characteristic points of ossification found in each of the three first sacral vertebra;, which are placed immediately above the three upper anterior sacral holes, exactly in the line of pressure from the ilia to the median line (b). These appear, from above down- wards, at the same time as the posterior la- teral centres just described. They unite first with the posterior lateral osseous points of their respective vertebrae, and with them join their respective central masses. Consequently, the three first sacral vertebrae have each five primary ossific centres, and the two last, each only three ; the whole number of jmmary points of ossification in the sacrum being thus twenty-one. At the age of sixteen years, the epiphysial or complementary ossific points begin to form, viz.: — On each articulating surface of the bodies of the sacral vertebrae is developed, as in the true vertebra;, a horizontal jjlate of bone, which, after coalescing with the bodies to which they respectively belong, finally (ex- cept the firsc and last) become soldered to each other from below upwards, commencing with the two last vertebrm, at from the six- teenth to the eighteenth years, and com- pleting the formation of the sacral bone by the union of the two first vertebrae, at from the twenty-fifth to the thirtieth years. Be- tween the eighteenth and the twentieth years begins the formation, by scattered granules, of four lateral plates of bone — one on each side, forming the iliac articular surfaces, opposite to the three first vertebra; — and one on each side, opposite the two last. These unite with the sacral bone about the same time that its upper vertebrae coalesce. The number of complementary points of ossification in the sacrum will thus be found to he fourteen, and the total number of sacral ossific centres thirty-five. M. Weber, however, assigns nine points of ossification to the first, seven to the second, and five to each of the three lower. The coccyx is ossified by a single centre for each of its four pieces. Occasionally, in one of the upper are two ossific points. That of the highest piece first appears about the time of birth ; that of the second bone is next evident, according to Bedard, at from five to ten years of age ; the third, at from ten to fifteen years ; and the fourth, at from fifteen to twenty. The two upper first unite together, then the two lower, the bone being consoli- dated by the union of the tw'o resulting por- tions at various periods of life. In advanced life, and, more frequently, in the male subject, 121 this bone is often found ankylosed to the sacrum. According to M. Weber, each coc- cygeal vertebra has two to four points of ossification. Pelvic Articul.vtions Ligaments. — The articulations of the pelvis arrange them- selves into ; ] . those connecting the pelvis with the spinal column, or lumbo-pelvic articu- lations ; 2. those of the pelvic bones with each other, or proper 2wlvic articulations ; 3. those connecting them with the thigh bones, or femoro-pelvic articulations. The second class of articulations are those with which we have more immediately to do. The first class may be alluded to as necessary for elucidation of the subject. The last class come more particularly under the consideration of the hip joint. The ligaments of the pelvis are of tw< kinds: 1. those which are closely connects w'ith the several articulations, or intimate liga- ments ; and, 2. those which connect distant portions of its osseous structure, and are com- plementary to the articulations or accessory ligaments. The former will be best described with the articulations of which they form part, Lumbo-pelvic articulations. — The sacrum, and throngli it the pelvis, is united to the last lumbar vertebra by exactly the same meanf as the vertebra; to each other, viz. ; — First by an amphi-arthrodial joint, composed of a thick disc of fibro-cartilage intervening between, and adherent to, their opposing articular surfaces ; and strengthened by a continuation of the anterior and posterior common ligaments to the sacrum. Secondly, by two arthrodial ]oi\\ts invested with capsular ligaments, one for each of the articular pro- cesses. Thirdly, by the lowest members of the Ugamenta subfiava connecting the laminm of the vertebra; with those of the sacrum, and by the lowest inter-spmous and supra- spinous ligaments connecting their spines. And, lastly, by an accessori' ligament, which is a representative of the inter-transverse or oblique trail sverso-costal ligaments. This extends from the lower border of the last lumbar transverse process on each side, to the lateral masses of the base of the sacrum, its fibres expanding to the sacro-iliac sym- physis and iliac crest. It is called the sacro- vertebral or lumbosacral ligament. The fibro-cartilaginons disc is composed, like the other intervertebral plates, of an obliquely intersecting layer of fibres externally, and of a central, soft, pulpy portion, and differs only by gradually becoming mucb thicker ante- riorly, like the body of the last lumbar ver- tebra itself. This allows of the curve of the spinal column at this part, which is the most salient point of the sacro-vertebi al angle. The movements of this joint are a limited antero- posterior motion with slight lateral flexure, somewhat less than that of the rest of the spinal column. Proper or intra - p)elvic articidations. — These consist of a joint uniting the sacrum and cocc} X by a miniature amjjhi-arfhrosis ; of a joint on each side uniting tiie sacrum to 122 PELVIS. the innominate bone posteriorly ; and a single joint in front, uniting the innominate bones to each other. The three latter joints are of the kind usually denominated “«/?«- physis,” and considered by many as included also in the class “ amphi-arthrosin.” The sacro-iliac joints, however, most fre- quently presenting two coa//g!«)ew surfaces and t wo sc|)arate [dates of incrusting cartilage, ought rather, as Albiniis remarked, to l>e considered as “ arlhrodial" forms of articulation, while the pubic symphysis occupies an intermediate or transitional position between the fihro-carli- laginous or mixed, and the arthrodial joints. The sacro-coccygral joint is comjtosed of a fibro-cartilaginous disc, and an anterior and posterior I'gament. The fibro-cartilaginous disc is a miniature of the intervertebral, inter- vening between and adiierent to the opposed articular surfaces of these bones, being, how- ever, less evidently |)ulpy in the centre. Ac- cording to Cruveilhier, there is sometimes found a synovial mendnane in the centre of this joint. The anterior sacro- coccygeal liga- ment consists of a thin layer of fibres passing from one bone to the other in I’ront of the joint, and S[)reading over the whole coccy- geal surface. . The posterior sacro-coccygcal ligament is much stronger and more developed. It springs from the edges of the notched in- ferior opening of the sacral canal by a thick band of fibres, which includes also, as an in- vesting capsular ligament, lined by a synovial membrane, the articular extremities of the sacral horns, and, gradually narrowing down- wards, is attached to, and extends over, the whole posterior surface of the coccyx and its articular processes, covering in the inferior aperture of the sacral canal, and connecting the several pieces of the coccyx when they remain separate. In the latter case also are founti intra-coccygeal articulations, small fibro- cartilaginous discs intervening betw’een the several bones. This, according to Levret, is most constant between the first and second pieces of the coccyx, where it is sometimes met with in advanced age. The motions of this joint, and those of the coccygeal bones, are simply antero-posterior flexure, and aresometimes, especially in females and young subjects, very extensive, forming, Cruveilhiersays, a complete anterior projecting angle. This anatomist also mentions having seen many times anterior sacro-coccygean mus- cles ; other anatomists also mention posterior sacro-coccygean muscles blended with the fibres of the ligament. The sacro-iliac joints (y%. 80. 1 .), one on Fig. 80. Anterior view of the f all-grown male pelvis with its ligaments. 1, sacro-iliac symphyses; 2, pubic symphysis, a, superior sacro-iliac ligaments; 6, anterior sacro iliac ligaments; c, ilio-lumbar ligaments ; (/.anterior pubic ligament ; e, superior pubic ligament ; /, subpubic or arcuate ligament ; jr, obturator membrane ; h, sacro -sciatic ligaments; i, sacro-luuibar libro-cartilage, forming the sacral promontory. each side, are composed of an anterior or inferior portion, in which the opposing bones are covered with cartilages of an auricular or angular shape, and a posterior or superior portion where they are united by powerful inter-osseous ligaments, which fill up the re- tiring angle left by the cartilages. These are inclosed by anterior, posterior. Mid sujyerior sacro-iliac investing ligaments. H\\s cartilages lining these articulations differ PELVIS. 123 from those in the pubic symphysis in being al- most totally wanting in the fibrous elements which are in the latter joint intcrmingleil with them. Under the microscope a section of the sacro-iliac cartilages presents the ordinary ap- pearance of cartilage incrusting the surfaces of arthrodial joints. They have been said by many writers to be completely incorporated together so as to form but one mass; but such is not the conclusion I have come to, excejtt in a few cases, after many examinations care- fully made in subjects recently deceased. The cartilages are very strongly adherent to, and follow exactly the shape of, the auri- cular articulating surfaces of the sacrum and ilium before described, their rounded pro- jecting angles being the most depending part of the articulation. That on the sacrum is almost double the thickness of the iliac cartilage, which is somewhat less than one eighth of an inch thick. In the male, in a few instances, the two seem to project into each other by irregular prominences, and to be con- nected without the intervention of a regular synovial membrane. In these cases it has been remarked, that on the ajjplication of force, the cartilage separates from the ilium, leaving its auricular surface denuded. Much more frequently in the male, however, and always in the female and child, I have found, extend- ing between them throughout, a completely smooth surface, apparently lined by a delicate membrane, and containing much thick synovia. The opposing cartilaginous surfaces are, in these cases, wavy or /-shaped, when seen in a cross section, the sacral part being convex, and the iliac part concave in front, the re- verse arrangement having place behind, the greatest depression being in the iliac surface, exactly at the angular junction of the two limbs of the auricular surfaces, at the most de- pending [)oint of the articulation, and through which passes directly the line of pressure here- after to be noticed (see Jig. 89. page 144. c,/). At this point also, the breadth of the cartilaginous surface is the greatest, being generally about an inch. Towards the extre- mity of each limb the width gradually becomes less. The inferior or horizontal portion is longer than the other, generally being about two inches long, the superior or vertical por- tion being an inch and a half long. Immediately posterior to, or rather above, this cartilage-covered surface, and filling up the digital depressions found there on each bone, are firmly implantetl the inter -osseoux liganu ids, composing the remainder of the articulation. These consist of very strong and coarsely interlacing fibres passing almost directly from bone to bone, inclosing large meshes which are filled with a soft loose synovial looking fat, and containing many veins. Behind, these are continued into the deep posterior sacro-sciatic ligaments. The superior sacro-iliac ligament (/g. 80. aj is a strong layer of fibres passing from the lateral masses^ of the sacral base to the pos- terior edge of the internal iliac fossa. It is continued in front to the anterior sacro-iliac ligament (b), 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 doivnward 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 inierior 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 superjicial layers of fibre.s. 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 su[)erior 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 superjicial 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 into 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 Jourth transverse tubercle, which is the most prominent tubercular pro- jection in the dried bone. Bichat erroneously calls it “ saa'o-.sqjinous.” Attached to the same sacral tubercle, and passing horizontally outw'ards 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 {Jig. 81. b), which, being separated by a dis- tinct cellular interval from the deep ligaments ami distinguished by the more deeply seated position and horizontal direction of its fibres from the oblique ligament (a), and from the PELVIS. great sacro-sciatic ligament (r), T tliink merits the name of the inferior or short superficial posterior sacro-iliac ligament. This ligament has been hitlierto apparently conronnded with the great sacro-sciatic, which is attached to its lower border by a thin fibrous extension. Fig. 81. Posterior view of the ligaments of the pelvis. a, oblique posterior sacro-iliac ligament ; b, infe- rior posterior superlieial sacro-iliac ligament; c, great sacro-sciatic ligament; <7, lesser sacro-sciatic ligament; e, membruuous expansion over the pyri- formis muscle. The ligaments which may be consnlered as accessory to this articulation are three in number — the ilio-lumhar ligament above, and the greater and lesser sacro-sciatic ligaments below. The ilio-lumhar 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 iiim, respectively, the tipper and lower anterior pelvic ligaments, the latter corresponding to the sacro-vertebral ligament before described. The great sacro-sciatic ligament {ligamenlum pelvis posticiim magnum, fig. 81. c) is attached liehind, to the posterior interior spine of the ilium by a membranous expansion (e): to the snperficiid posterior sacro-iliac ligaments with w hich its fibres are bleiulcd; 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 ai'e arranged in fasciculi, which cross each other in an X-like manner, so as to [)resent, 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 op[)osite direction to become external. Its superior border, consequently, is directed outwards and forwards, and its inferior border inwards, and both present a ciu'viliuear outline. At its insertion into the sciatic tuberosity, the fibres of the lower border pi'e.sent 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 iu- feriorly into the tendons of the biceps llexor 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 gluteus muscle, which causes it when dissected to he very rough and floccnlent. At the posterior half of its inner surface it is blendctl intimately with the. lesser sacro-sciatic- ligament, anterior to which it is smooth, and forms part of the boundary of the ischio- rectal fossa. Tlie lesser or internal sacro-sciatic ligament {ligamentum pelvis posticuin parvum, fig. 81. d) lies internal to the last, in common with which it is attached posteriorly to the .side of the tw'O 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, ami 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 pndic vessels and nerves into the pelvis This ligament, thus passing from the sacrum across to the ischium, converts the sacro-. scia- notch into a triangular or oval foramen thre ! which pass the pyi-amidalis muscle, the g, -;al, isclradic and pudic vessels, and the superi gluteal and great and lesser sciatic and I . ' I nerves out of the pelvis. With its PELVIS. 125 Rnterior 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 dissccteil. 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 ami 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 symphijsis (Jig. 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 JMedical 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 (Jig. 82. a, a), of a denser and more cartilaginous structure than the rest, each strongly adherent to the bone by mammil- liform Jibroits 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, (r/) Dr. W. Hunter remarks, with Sandifort and Albinus,that the two cartilaginous plates (a, a), 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- Fig. 82. Symphysis pubis after maceration. a, cartilaginous plates of Dr. Hunter; b, mam- millary processes on their osseous surface; o, cor- responding osseous depressions to receive them ; d, inter-lamin.ar concentric tibro-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 disjilacement of the cartilage in that direction. The inter-laminar Jibro-cartilagin- 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 (Jig. 80. r/) is a thick layer, passing between the anterior sur- faces of the bones, strengthened by and blended wdth 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 lignmcntK the most feeble. It is composed of transverse fibres, somewhat scattered, and is remarkable in being rai.sed 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 laver 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 oidgin to the recti ab- dominales and pyramidales abdominal muscles, and linea alba. 126 PELVIS. The inferior or suh-jTiihic ligament, {Uga- mentum arcuatum, f ) is tlie most povverfiil, passing I'rom one descending rainns of the pubis to the other in an arched form. Its place of attacliment to the pubis is often a well-marked surface, triangular, with tlie base upward, and half an inch in dc[)th, cor- responding in this respect to the outline of the section of tliis 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 tlie deep [lerineal fascia or triangular ligament, be- tween which it gives origin to the vertical compressores urethra, and forms the superior boundary of the [lubic arch, the :ipex of which it roniuls off and smoothens. The movements of the pubic symphysis are confined to a slightly yichling 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 la}'ers of fibi'es, intermin- gling in a circular direction, and generally congregated more in some [ilaccs 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 attaclicd to the posterior sur- face of the ascemling 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 [lassing over from one edge of the sub-pubic notch to the other, so as to form the lower boundary of a foramen for the [las- sage of the obturator nerves and vessels. Opposite the cotyloiil notch its fibi'es 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 [losterior surface, to the internal muscle of the same name. It is some- times deficient in one or more places. General arrearance 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 stqterior 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- rositv on each side. It presents the pubic svm[ihysis directed downwards anil forwards in the median line, and the obturator fora- mina directed forwards, outwards, and down- wards on each side. As first noticed by Cuvier, this oblique direction of the sym- jjhvsis 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, wdiich may be 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 ischuim and pubis, forming what is termed the suh-puhic 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 tlie 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 sui'face 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, ne.xt 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 rccejition 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 iqiper surface is on a level with their most elevated central portion. Below the sacrum, the coccyx projects downwards and forwarils in a salient median point, which separates and completes the inner boundary of the sciatic notches on each aide, converted into foramina by the greater and lesser sacro- sciatic ligaments. The distance of the edge.s of the saci'um and COCC3 X 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 isgretiter 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 mternal surface of the pelvis, which presents two well contrasted portions, divided by a rounded edge or border, of which the su]rcrior is wide, expanded, anil deficient in front, and is called the targe, or false jielvis ; and the inferior, narrower, more complete, and more compact, is called the small, or true jidvis ; while the border w hich 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, ilirected 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-iiiacjoint,tothe thick rounded ridge on the inner surface of the ilium, whicli 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 symphysis 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 w'ill 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 aLo 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 downvvards 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 posteri r!y, separated by three notches, placed opposite to each prominence respectively, viz., the sacro-sciatic, postero- laterally, 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 whicli the lowmr 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 transvei>e one betw'een the ischial tuberosities. Of the prominent osseous points here seen, the lateral ischial tuberosities descend much lower than the symphysis pubis and coccyx, cn 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 tlie inferior outlet, from the same cause, do not, like those of the siqierior, lie all in one plane or level, but are bent, as it were, at the ischial tuber- osities, into two |)lanes ; 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 consideretl to be markcil by a straight line joining the lower border of the symphysis pubis and the ti[) of the coccyx ; and its general direction to coincide with a line drawn peiqjendicular to this plane down- wards and backwards. Dijferences 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 {Jig. 83.), the bones are lighter, shorter, and broader, less evidently marked by tuberosities and indentations re- sulting from the attachments of the tendinous structures, aiul have in a less degree the pecidiarities, 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 .y-like curve, the iliac wings are thinner and more expanded, and tlie 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 towarils the Inferior outlet, and with the tuberosities arc 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 pubes are thinnei’, narrower, and more oblique, turn their inner borders more forwards, and at the same time afford a more roundeil expansion to the pubic arch, at the expense of the obturator foramina, which are thereby rendered smaller aiul more triangular in the female. The si/mphijsis of the ptdns is not so deej), and the fibro-cartilage is wider, thicker, and more vertical in position ; the united angles are more flattenerl 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, ami 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 [)aper, 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 was greater by j- to 5 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 a[)parent 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 ami more regular. The experiments of Mr. Ward, however, correspond more entirely with my own obsei'vations on tins 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-scialic 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- vients 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 measurement. a h, conjugate diameter of brim ; c d, diagonal ditto ; e f transverse ditto ; g h, transverse diameter of inferior outlet. The 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 thej' 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 commonlj' spoken of as the diameters of the [telvis. 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 up[>er 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 ( 3 5 4 4 ‘ Oblique - 3 2 4 0 Antero-posterior . 3 3 4 4 3 0 4 6 3 5 4 0 ' Measurements. Between the anterior superior iliac spines - - - - 7 8 8 6 9 0 11 0 ■= 8 8 10 0 Between the centres of iliac crests 8 3 9 4 Depth of true pelvis — Between the upper and lower border of symphysis pubis - ■ 1 10 1 6 2 0 1 7 : Between the ilio-pectineal eminence and ischial tu- berosity - 4 10 3 6 4 5 3 8 Between the sacral promontory and tip of coccyx 4 10 5 0 4 6 V 5 m. to / 6 in. ' Depth of whole pelvis — Between the iliac crest and ischial tuberosity - 8 7 7 5 f i Between the anterior superior iliac spine and ischial tuberosity - 6 5 6 0 „ posterior siqierior iliac spine and ischial tuberosity - 6 0 5 5 i Between the lower border of pubic sy mphysis and sacral promontory - - - 4 7 ; „ spines of ischia - - - 3 5 4 3 „ sacro-iliac joints (greatest breadth of sacrum) - 4 3 4 8 s “ 4 inclios (Burns, Ramsbotham, Lee, Cloquet, Velpeau, and Laudelocque). inches (Monro and Boivinj. 4’3 inches (Rigbj'). •> 4 inches (Burns, Lee, and Cloquet). 4A inches (Monro and Murphy). <= Increased to 5 inches or more by the mobility of the coccyx. •' to inches (Burns). 9'G inches (Cloquet). “ 10 inches (Cloquet). 11 inches (Burns), f 7 inches (Cloquet), s 4 to 4A inches (Cloquet). 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 to the sacrum, which, allowing i inch to each of the sacro- iliac cartilages and \ inch to the pubic, gives a total circumference of 151: inches. In the well-made female the ilia were found to be each 2i, the pubes each 3jr, and the sacrum 5 inches, giving, with the same allowance for the sacro-iliac cartilages and tV inch for the pubic, a total of 17J 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 15, 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 [lortions.* * The circumferential measurement appears to be one not generally estimated as much as its utility ; in detecting variations of size depending upon s/ia/)e4 would seem to call for, in the female pelvis. A; f reference to the subjoined table of variations of dia- I PELVIS. 131 Burns gives also, in the female pelvis, the following distances: — 1. Between the symphysis pubis and inferior iliac spine, nearly - - L in. U 2. sacro-iliac joint and the pubic crest of same side - 3. >> sacral promontory and the obturator notch 4. ’> sacral promontory and the acetabula 5. acetabula anteriorly - 6. posterior ridge of ilium and the su- perior and inferior anterior spines - 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 5-f and Stoltz in 40 female pelves, found the mean distance to be 3 pouces, 3 to 4 lignes {pied du Koi). 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 pi’omontory,” one antero-pjosterior, 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 3A 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 compensatory to each other ; as this compensation may occur in diameters not nsually measured, tlie (Circumferential extent seems in many' cases to he required. Dr. Churchill gives the circumference jif the brim as varying from 13 to 14i inches in the •emale, much less than I have generally found it on ihe 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 vaiy 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 mav 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 : — 1 . From the sciatic tuberosity 1 of one side to the posterior ( superior iliac spine of the j other side - - J 2 From the anterior superior I iliac spine of one side to ( the posterior superior of | the other side - - I 3. From the spine of the last 1 lumbar vertebra to the an- 1 terior superior iliac spine j on both sides - -J 4. From the great trochanter "j of one side to the posterior ( superior iliac spine of the f other - - - J 5. From the middle of the in- ' ferior border of the sym- physis pubis to the pos- terior superior iliac spine on both sides Mea* sure- ment. Greatest Dilie- rence. in. lines. lines. 6 6 3 7 3 3 6 8 4 to 5 8 .5 6 4 2 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 1 1 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, forty- 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 consitlered 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 If 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 w'ell-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, ol tile pelvis, tlie general inclination of the The line so drawn will generally be found to Vabiations 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 Case.s). Extremes. Most fre- quent. Extremes. Mo.st fre- quent. Inclined plane of promontory — inches* inches. inche inches. Antero-posterior - *3> or to 5h 4\ to 41 To left pectineal eminence- *3 or 3j to 4| 3^ to 3| To right pectineal eminence *2| or 3| to Brim — Antero-posterior *3| or 3^ to 4 3fo 43 Transverse t3|or4^ to,5§ 5.1 5 to H 5 Oblique { : : *4j or 4f to 5^ *4|or 4^ to 5\ ^ ] 5 and 5£J 43 to 51 5 and Between promontory and lower edge of symphysis pnbis - - to 53 43 and 5 Cavity — Antero-posterior *4Jor4ito 5} 5 41 to 43 and 53 'I'ransverse *3| or 4\ to 5| 5 - - Between ischiadie spines - - 3J to 43 Outlet — Antero-posterior J3g to §4^ 4 to 4| 31 to 43 4 'I'ransverse §3;i to j.'r 4j to 4] 33 to 43 41 Oblique (6 cases only) 31 to 43 4 Angle of pubic arch 45° to 100° 70° to 90° * Like male pelvis, diameters small. t Smallest pelvis, transverse diameter of cavity 4|, of outlet 4§. j Belong to the same pelves respectively (compensating diameters). pass also through tlie bodies of the first dorsal and second lumbar vertebr® across their centres. Tlie curved line of the vertebrae, in most well-formed subjects, cuts the straight line at these two [mints, 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 niinlc of inclination of the pelvis, or the pelvi- vcrtehral angle {Jig. 8^. page IS-f.), {ae,ec). It is remarkable that, in man only, are the boundaries of the superior outlet in one plane. i. e. in wan only is the direction of the superior jmhic ramus in the same plane with that of the colylo-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- vcrichral angle is thus resolved into two angles, a vcrtehro-iliac and an ilio-pnibic. The angle of the supenor plane was found by the Webers on the dead body, by fi.xing the connected s[)inal column and pelvis of a recent w’ell-made subject, in plaster of Paris, to preserve the natural position, then making through the whole a direct vertical section, and afterwanls 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 veHical direction, and fall exactly in the trans- verse vertical plane of the vertebrae (see fig. 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 dro[)ped 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 [lelvic angle.? it must be borne in mind that the direction of the curve of the three last lumbar vertebras, below the point where the great dorsal con- cavity terminates, is such that, if prolonged u|)wards, the axial line would pass out at the junction of the manubrium with the body of the sternum. This makes the pelm-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,fig. 8^. prage 134.). PELVIS. 133 By an inverse method, proceeding on Roederer’s plan from the horizontal plane {Jig. 84-. g, rf), Naegele determined, with great care, the angle of the inferior j)lane of the pelvis in the living female. In 300 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 434 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. 7’1 lines, drawn from the observations above detailed. From this he deduced the inferior angle of inclination of the pelvis (fgd) 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 73'8 millimetres. From these measurements they obtained the angle of the inferior pelvic plane with the horizon 16°’31. 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, they 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 (lelvis the two lines of the superior and inferior planes, when prolonged anteriorly, cut each other about li inch anterior to and below the pelvis (at c), containing an angle of about 30° c/) ; 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 pi ocess 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 was 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. Angle of Inclination of superior plane, or pelvic brim. Male (Weber). Female {Nae- gele). With transverse ) vertical plane - j With horizon 155° 65° 150° to 151° 59° to 60° Of inferior plane, or outlet. With transverse \ vertical plane - ) With horizon 106° 51' 16° 51' 101° to 102° 10° to 11°* By 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 33° with the horizon, and, by Osiander, at 30°. Cams gives the superior at 33°, and the inferior at 11° with the horizon. Angles of the anterior and posterior pelvic walls with the transverse vertical plane. — The pelvic inclination, in the opinion of Cm veilhier, depends upon the angle which the sacrum forms with the spinal column, giving more or less of obliquity to the inno.minate bones on each side. This angle {fig. 84. next page, a e t, and Jig.\\2. \. f a g, page 173), which maybe called the sacro-verlebral angle, I have, in as many opportunities as have oc- curred to me, endeavoured to ascertain and establish, with a view of coni|)aring 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 saernm. 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, show'ing 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 Naegele here given. Naegele remarks that the inferior angle is much more variable than the superior in ordinary cases. PELVIS. 131 III twenty-five males, Nine were from 1 1 6^ to II 2°, five from 1 15° to 1 17° 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 subjcjt, 118° only. Fig. 84. Diagram (^slightly altered from Naegele') of a well- formed female pelvin, showing the angles of inclina- tion and axes. From these we may deduce 117° as the average sacro-vertehral angle in the male., and 130° as the same angle in the female. This remarkable average difference of 1.3° shows the much greater suddenness of the altera- tion of direction in the spinal cohiinn 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 if 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 sacro-verte- bral was as large as the pelvi-vertebral angle. From these observations, which were very carefully taken, it would seem that the total jtelvic inclinalion does not exactly depend upon the sacro-vertebral angle ; and that, in mates, 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. « 5 A-), which will be found to betibout 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 |>elvic wall to be often at right angles to the plane of the inlet, but the posterior generally somewhat more than a right angle. Idle 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. Itio-ischial 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, ibrming an angle of 1 10° to 115° with the same rib of bone (see fig. .1 12. \. 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 o*" 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 ilio-pubic angle. Angle of ischio-piibic arch. — The angle at which the iscliio-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 figs. 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 ap[)lied 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 {Jig. 84. /, m). 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° (« 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 he 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 (n, 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 coccy.x is in a position of extreme extension, however, its tip describes the curve m,s, 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 (.? g d) dimmished. 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, ?■), drawn, like the former, from the point of junc- tion ot 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 urefxed, 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, q), as the coccyx moves bachwnrd in the curve (?h, s'), a de- viation which facilitates the exit of the fcetus in parturition. This forwaid direction of the axis at this part is increased also by the rounding off of the symphysis pubis at its inferior border. Each of the three portions passes midway between the corresponding and opposing surfaces of the symphysis pubis and sacro-coccygeal wall, the general vertical outline of which it nearly resembles, and be- tween the lateral ilio-ischial columns. The latter, being equally inclined to each other downwards, cause no deviations in the plane w'hich forms the centre of their lateral dis- tances. So that the so-called n.vis of the pelvic ca- vity is not one right line, as stated by Mul- ler and Koederer ; nor is it properly ex- pressed by perpendicular lines drawn from three planes, as Levret suggested ; nor bv a continuous geometric “ arc decercle,” from the superior to the inferior plane, as G. Bang, Choulaut, Camper, and Cams concluded ; nor by the meeting of the axes of the superior and inferior outlet, as is somewhat loosely' stated by some more modern writers on ob- stetrics ; but it is a more or less irregular parabolic curve, passing from tlie fixed axis of the brim, and moveable forwards at its inferior extremity with the moveable axis of the inferior outlet, with which it coincides below. It may be here added, to prevent mis- conception, that the line of direction of the inferior outlet is in the living female inclined forwards in a much greater degree {n, b), than that of the osseous pelvis, by the prolongation of the posterior wall in the soft parts of the perineum. General Development of the Pelvis. — In common with the inferior extremities, the pelvis, in the infant, is more tardy in arriving at adult perfection than the upper parts of the body ; and this delay is more evi- dent in the inferior or true than in the su- perior pelvis, and considerably facilitates its transit through the maternal structures. At birth, the iliac wings are flat, and their sur- faces are directed more forwards and less in- wards than in the com|)letely formed pelvis. From the narrowness of the sacrum, and the shortness of the pubes, the transverse di- mensions of the brim ami cavity are very small, and the antero -posterior diameter, from this cause, is larger than the lateral, by i to i an inch. The shape of the superior open- ing is less rounded than in the adult, being of a sub-quadrate rather than an oval form. The cotyloid part of the ilia is completely cartilaginous, contracted, and less projecting, while the pubic arch is narrow and angular, K 4 136 PELVIS. and tlie tuberosities of the istliia are near each other so as to present a small opening at the inferior outlet. Soenimening remarks that •the obturator foramen is more elliptical in the infant than in the adult. The depth and general apj)earance of the true pelvis is smaller than is proportionate to the iliac ■wings ; and it is of nearly equal breadth throughout. 'VUe parnllelhm of the lateral, as well as of the anterior and posterior pelvic walls is, I think, sufficiently marked and general to be considered as a characteristic of the con- formation of the infant pelvis, as we shall find it to be of that of most of the lower animals, giving to it a square-sidedness which is well seen in the adjoining figure. Fig. 85. Pelvis of the Child at birth. The sacrum and coccyx in the child at birth are much less curved, vertically, than they afterwards become, which causes the posterior wall to be longer than is propor- tionate. The coccyx, indeed, in many in- stances I have seen, was almost vertical. The sacro-vertebral angle is consequently much less marked than in the adult. Doubt- less, muscular action, increasing as the de- velopment of the bones progresses, has a great effect in producing the diminution of the sacro-vertebral angle backwards in after life. It is commonly stated by anatomists, that the infant pelvis is more obliquely placed on the spinal column than the adult pelvis. The inclination of the superior plane in the child has been placed by the brothers Weber at an angle of 15-I’66 with the transverse vertical plane. This is somewhat less than tlte in- clination in the male, according to the same observers, viz. 155°. The following table is the result of the measurements of the pelvic ant;lcs of five infants, made to ascertain the correctness of this statement. The angles were carefully taken, with much precaution against any ab- normal displacement, so readily occurring in the pliant structures of the infant, by making an antero-posterior vertical section of the pelvis and wdiole spinal column with the wiiole of the soft parts attached, ami in such a manner as woukl have tended rather to in- crease, than to diminish, the pelvi-vertebral angle. Angles. Pelvi- Sacro. verte- verte- hral. bral. 1. Foetus at 6 months, /cma/e 150° 155° 2. „ „ mule - 150° 145° 3. Infant at full term, 7 days ) 150° 145° old, female - - ) 4. Infant at full term, } female - - - y 5. Infant at full term, still j horn, large and well- > 150° 140° 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 adidt. 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 Cruveilhier, 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 {fig. 84.). In all the infant pelves 1 have just given, the ti]) of the coccyx reached as low as the lower border of the synqdiysis pubis ; both these points exactly coinciding with a line drawn perpendicular to the transverse verti- cal plane. This may, |)erhaps, 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, t\\e angle of inclination of the pubic symphysis to the transverse vertical plane was only 25°, but in the last female child it was, 40°, both being less than the mean adidt angle, 50°, before given, and showing, like the sacra- 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 [uiberty, a cir- cumstance very necessary to be borne in mind in opeiations on these viscera in chil- dren below that age. Hence one cause of the greater proininence 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 tliat 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 Autenrietb’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 two 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 %uliole 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 w’ill 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 groups 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 midlijidus spince, to the iqiper part of the posterior surface of the sacrum ; the interspinales, 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 lalissimus 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 cxter- nus and mternus, and iransversalis 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 [lectinea; 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 q^yf'amidalis abdo- minis, to the crest of the pubis ; and the josoas qjorvus, 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 wdiole anterior concave surface of the iliac wing — the qjsoas 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 cruris, semitendinosus, anti semimembranosus, to the depending middle and posterior parts of the ischial tuberosity ; and the gluteus maximus, 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 gracilis, to the rough internal border of the ischio- pubic rami and symphysis pubis. The abductor group. — The gluteus medius, to the dorsum of the ilium, between the crest and stqierior curved line ; the gluteus minimus, to the same surface between the curved lines ; and the tensor vagincB femoris, to the outer surface of the anterior superior iliac spine. The rotator group. — The pyriformis, 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 138 PELVIS. it is bent as over a pulley) ; the gemellus su- j)erior, to the outer surface of the ischiadic spine; the gemellus inferior, to the posterior extremity of the ischiadic tuberosity ; and the qiuulratus femoris, to the external border of the same tuberosity. 3. Aluscles acting on the perineum and ge- nitals.— The perineal group. The levator ani, to the middle of the inner surface of the symphysis pubis, to the inner surface of the ischiadic S[)ine, and to the tip of the coccyx; the ischio-cocci/^eus, 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 frans- versus perinei, to the middle of the inner border of the ischial tuberosity; the accelerator urincB (or, in the female, the sphincter vagince), to the anterior [>art 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 compressores 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 fascia;, which are susceptible of division into lumbar, abdominal, crural, pelvic, anil perineal. The lumbar fascia is formed by the junction of the tendon of the latissimus dorsi muscle with the fascia vertcbralis, 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 fascia; transversalis, attached along the inner li[) of the iliac crest, to Poupart’s ligament, and to the crest, spine, and pec- tineal line of the jnibis ; the fascia of fliequa- dratus lumborum muscle, or anterior division of the tendon of the transversalis, attached to the inner lip of the ]iosterior 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 iVmc portioTi, which separates tlie lateral abdominal from the external leg muscles ; the siiine, crest, angle, pectineal line, and descend- ing ramus of the pubis, to the jnibic portion, which separates the internal leg muscles from the anterior abdominal and anterior perineal group of muscles ; and the tuberosity aud ascending ramus of the ischium to the ischiadic portion, which separates the jiosterior leg muscles from the posterior muscles of the perineal group. The pelvic fascia is composed of two por- tions, the recto-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 and 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 s|)ine. 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 2>crineal fascia covers in the anterior perineal region, and is attached to tlie 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 Homan 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 wi'li 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 ivhole bodp, 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 Rokitanski, 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 voiissoirs, 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 cofylo- 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, wdiere it is almost circular. renders them less ableto support heavy weights; and on account of the greater distance to Fig. 86. I! A, diagram of the pelvic arches: — 6, o, cotylo- sacral arch; c, a, c', Ischio-sacral arch; h, d,U, cotylo-pubic tie; c,d,d, ischio-pubic tie. B, diagram of pelvic levers : — c,a, line of gravity; F, h, pubio lever ; f, w, cotylo-sacral lever ; w, p, posterior spinal or iliac lever ; p, c, direction of spinal power ; w, c, direction of spinal w'eight ; 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 outwards, 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- 1-iO PELVIS. sacral arcli, but it resists tlicir displacement inwards, which would result from tlie pressure of the femora in tlie direction of the necks of these bones. The effect of this pressure, when tlie pubes yield to it, is shown in the de- formity which has been termed the rostrated jielvis, resulting from the crushing of these bones together. The cotylo-pubic arch also receives, in its concavity, part of the weight of tlie 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 coecuni 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 viseera which the erect position ileniands, 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 tivo 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 synijiliysis 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 tripoil, on the apex of which the femur is sujiported. 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-sarral is the central and principal one, the ischio-sacral the lowest and next in strength, and the suj>eiior or indirect cotylo • sacral 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 dynamie 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 upwards and backwards, wdiile 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. u). Fig. 87. Dr-awing of a section o f the pelvis in the cotylo- sacral arch, removing the left iliac wing, a, a', line of falling in the transveree vertical plane of trunk ; c,e', line of weight passing through centre of sacro-iliac joint ; h,V, line of power or pubic pro- jection ; d, d!, line of sacral projection ; e,f, cotylo- sacral curve; al,V, 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 jtower, 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 weil- formed male pelves, the pubic arm of this lever is increased in power by being longer than the cotylo-sacral by -h or f of an inch, the one being 2 inches, the other 1 ^ inch, in PELVIS. HI direct distance from the centre of the cotyloid support (Jig. 87. a' b' , a' c').* This gives the anterior muscles of the thigh greater power in resisting the downward force of the trunk at the sacral extremity of the lever. But by the addition of the iliac and sacral projections posteriorly, the cotylo-sacral arm is increased in length by 2^ inches, as will be observed on reference to the figure (o', d'), a disposition which evidently increases the power of the glutei muscles in maintaining the habitual erect position, and resisting any tendency to fall forwards, by extending the femora on the [>elvis. Again, if we follow the lateral curve of the sacrum at the brim of tbe pelvis, we shall find that it projects forward in the promontory of the sacrum, immediately under the point supporting the spine, so that its profile, taken with that of the ilium, as seen in the figure (e f), presents a curve with the concavity for- ward, in the manner of a C spring. It is worthy of remark, that, in the erect position, a plumb line, dropped opposite to the centres of the bodies of the axis and last lumbar ver- tebra, passes across the centre of the sacral promontory, and directly between the centres of the cotyloid cavities, as was proved by the experiments of Weber. Such a plumb line marks exactly the line of the transverse vertical plane of the spinal column before mentioned, which, when continued down- wards, passes through the sacral extremity of the pelvic lever, and also through the cotyloid 'fulcrum, dividing equally and vertically the heads of the thigh bones, and crossing the ischio-pubic rami about their suture (a a'). Thus, the oblique C-!ike curve of the cotylo- sacral arch, or posterior bent arm of the lever, meets this plane at its two extremities, di- recting its concavity towards it like the arc of a circle to its chord ; and contributes, by its elastic reaction, to break the force of shocks operating through the spine and fe- mora. In deformed pelves, we generally find that the sinking of the sacrum, the crown of the pelvic arch, under the weight of the trunk, produces an increased curvature of the iliac bones forwards by the yielding of the C spring, and thus still further encroaches upon the dimensions of the pelvic brim. The above considerations will illustrate the fallacy of the deduction of Cruveilhier in re- spect to the statics of the pelvis. This cele- brated anatomist remarks, that “ the arti- culation of the vertebral column with the pelvis is situated at the back part of that cavity, while the articulation of the femurs is anterior and lateral. The distance between them increases the space in which the centre of gravity can oscillate, without being carried so far forward as to pass beyond a perpen- dicular, from the cotyloid cavity to the base * The line cc', in the diagram passes through the centre of thesacro-iliac joint, — at which point, aline drawn from the cotyloid fulcrum of the bent lever falls perpendicularly upon the line of action of the weight, transmitted obliquely in the sacral axis, — and this consequently, the effective point of power of the bent arm/, e. of support at the feet” (p. 514. vol. i. Anat. Descrip.). Now these experiments of Weber prove that the centre of gravity is directly ever the cotyloid support, and cannot oscil- late between these two articulations. The only oscillation of the line of gravity which can take place without falling is along the length of the basis of support — the feet. Soon after, in reference to the sitting po- sition, he says, “ the tuberosities of the ischia being a little anterior to the cotyloid cavities, and near the front of the pelvis, the centre of gravity tends to pass behind the base of support; and the body easily falls backward in that position.” Now, the tuberosities of the ischia, in the erect posture, are consider- ably behind tbe line of gravity, or transverse vertical plane, which crosses at or near the ischio-pubic ramal suture ; and though, in the sitting posture, they are brought a little nearer the line of gravity, yet a much more satisfactory reason of the trunk more easily falling backwards than forwards, is because of tile support of the hams in front, and the eleva- tion of the coccyx behind above the plane of support. Again, by the projection of the sacrum and tuberosities of the ilia behind the sacro-iliac joints, another lever, less powerful than the foregoing, is formed, having also the cotylo- femoral supports for its fulcrum, and the spinal column for its weight, the anterior arm of this lever being the cotylo-sacral arch (fig. 87. a', c'), and the posterior, the over- hanging tuberosities of the ilia and projecting sacrum ( c', d'). Measuring from the centre of the sacro-iliac articulation, the anterior arm is Ij inch in direct length, and the posterior about 2 inches and a half. The power in this lever resides in the power- ful muscles which pass from the sacral anti iliac bones posterior to the sacro-iliac joint, to the osseous spinal projections and append- ages above— viz. the longissimus dorsi and sacro-lumbalis, and its action is shown in the increase of the pelvic inclination on the change from the sitting to the standing position ; the principal movement taking place in the sacro- lumbar joint. It acts to the most advantage when the centre of gravity of the trunk, from which it is derived, is thrown in advance of the cotyloid fulcrum (a a'), so that the lever, though apparently one of the seconil order (i. e. in which p and w are on the same side of the fulcrum), is in reality one of the first order, (in wdneh the fulcrum may be between them, and supports both the pow'er, p, and the weight, w. Hence, in the drooping of the trunk forwards in old age, the action of these muscles contributes, to produce the in- creased obliquity of the pelvic lever in the manner before described. This may be made more evident by inspection of the diagram (fig. 86. b), which is taken from a small brass model made to illustrate this point. It will be seen that the pressure on the cotyloid fulcrum, F, could not be w — p, as in the second order of levers, but must necessarily be tv + p, and therefore in the first order of levers, p, in this case, may be represented 112 PELVIS. by the line p c, and the line of gravity of v/e shall find all these requirements beauti- the trunk, ea, and is doubtless considerably fully provided for. increased by the resisting tension of the an- First. Tlie sacrum is wedge-shaped, when terior abdominal muscles acting through the viewed at its anterior aspect, narrowing from extensors of the thigh on the femoral sup- above dowmvard, especially along the surface ports in the line c b, h d. immediately between the lower portions of its In the foregoing dispositions of the pelvic iliac articular surfaces in the plane b, e {fig. structure, the office fulfilled by the .memm is 88. a), which are inclined to each other at so compendious and important as to call for an angle varying from 15° to 30°, and aver- particular attention to the shape and position aging about 20°. When viewed from above at of that bone, and the manner in which it is its base, as in fig. 89. pnge 144.), it also pre- articulated with the ilia, so as to be at once sents a wedge shape with the base directed anfe- firm and strong as a keystone, yielding as a riorh/, the lateral masses of the base becoming spring, and moveable as a jointed bone. And narrower from before backwards ; so that the Fig. 88. n A, diagram of the sacral auricular facet, natural size and placed as in the erect position of the hodij, with the lines of tension and pressure, a, centre uf action of the posterior deep ligaments ; J'/V, arc of sacral groove, forming a quadrant with the lines of tension, a d, a e; d e, chord of the arc; d f, e f chords of the semi-arcs ; (/ 9 c, sacro-vertebral angle; f/ i c, triangle forming the sacral “ voussoir ;” b and [e, position of sacral “joggles.” K, diagram of a transverse section of the pelvis in the line of the saeral axis, posterior view'; a c h, angle of vertical sacral wedge; rf, e, depth of sacro-iliac articulations; f, interosseous sacro-iliac ligaments. .sacrum appears to be a double wedge, having its broadest part at the border of junction of the base with the anterior surface, and tapering from this point, both upwards and backwards and downwards and backwards. Hence it has been stated by Cruveilhier to be liable to dislocation downwards and for- wards, from the want of bony support in that direction. But the sacrum, in the erect po- sition of the body, is jdaced, not vertically, but obliquely, with its base directed more forwards than upwards, and its anterior sur- face more downwards than forwards, so that the upper limb of the auricular surface is placed nearly vertically, and the lower nearly horizontally, as seen in fig. 88. a. The di- minished breadth of the base of the sacrum posteriorly is due to the bevelling of the lateral surfaces for the implantation of the deep posterior and interosseous ligaments, as seen in fig. 88. (b, e),the bone not being here in apposition with the overhanging iliac tuber- osities,— the area of absolute contact being confined to the auricular surfaces themselves. Again, the increased breadth of the anterior surface at the auricular angle c {fig. 69.), W'ill be found, on careful inspection, to depend upon the presence of the pointed projections on each side, before desci'ibed as received into corresponding depressions on the au- ricular surfaces of the ilia, which latter, being circumscribed below bj' a raised border, cause the sacrum to bite on the ilia here to a consider- able extent, forming what is called, in engi- neering nomenclature, a “joggle” to the sacral “ voussoir.” By the iliac support thus re- ceived, the position of the sacrum is well protected against pressures, coming either directly downwards in the line d, b {fig- SG.a^ or downwards and forwards in the direction ot PELVIS. 113 the line a,b ; b being placed in the diagram upon the sacral projection. By measuring in eight sacra, the distances between the upper extremities of the auricular facets on each side, at the point d, marking them off’ on paper, and then taking the distances in like manner at c, which corresponds to the lateral notch opposite the second sacral vertebra {see fig. 78. A, h.), I found the line d, c to coincide pretty nearly w'ith the mean direction of the superior vertical limb, and with the superior half of the central curved groove d, e ; and to fall in a plane which was inclined to the one on the opposite side, so as to form with it an angle varying from 15'’ to 25°, and in all cases directed dnwmvards. Now, the sacrum is so placed in regard to the cotylo-sacral arch, and the line of pressure from above, that the angle formed by the surfaces of the base and anterior face is the narrowest point of a rapidly-expanding arti- cular wedge placed antero-posteriorly. This is better seen by a lateral view of the auricu- lar facet, with the bone in the natural oblique position, as in fig. 88. a. The facet will then be seen to have its angular projection pointing downwards and forwards in the direction of the cotylo-sacral arch in the line a b, and its two limbs diverging so as to pre- sent a broad surface of articulation with the ilia in the lines b d, be, forming with d e, the triangular “ voussoir db e. The depth of the keystone is the greatest distance between the anterior border of the superior limb, d, and the inferior extremity of in- ferior limb, e (fig. b), and is about 2|'inches in the adult male. The wedge shape formed by them is well seen in the posterior view of a transverse section along the sacral axis, as in fig. B, where the lines a c, b c show the obliquity of the w'edge, and form an angle a c^, of from 20° to 35°. In a direction downwards and backwards, then, the sacrum has, like an artificial “ voussoir,” or keystone, its broad end directed ttyj tea rtfs towards the point of pressure. But, as Cruveilhier has justly observed, forces acting in the curve of the lumbar vertebrae are partly counteracted by the elastic spring-like yielding of the lumbar and sacro-lumbar fibro cartilages ; and by the lumbar curve they are, at the same time, di- rected backwards as well as downwards (viz., — at first in the direction of the linetf, / (fig. 88. a), and then in that of f, e, which latter, produced to meet the vertical line d, b, at g, forms an angle d g c, of about 1 17°, coinciding with the average sacro-vertehral angle in the direction of the sacral axis'), — ’thus tending to drive the broad end of the sacral “ voussoir ” between the narrower iliac intervals ; and so, in relation to the direction of the y;nn- cipal forces acting on the pelvic arch, the sacrum becomes a true keystone. Another arrangement which would tend, from the obliquity of the bone, to counteract any forward displacement, is the sudden in- version of the vertical sacral wedge at the ex- tremity of the lower limb of the auricular surface (y?g. B, c), opposite the third sacral bone, at which point, we have mentioned in the description of the sacrum, the anterior surface becomes suddenly broader from above downwards; so that here the sacrum by an- other “joggle” again bites on the iliac. A third disposition preventive of this displace- ment has been pointed out by Mr. Ward, in the superiority of breadth of the posterior over the anterior surface of the sacrum, op- posite the point c. (fig. a.), the middle of the inferior articular limb in many instances. Behind and above the angular |)rojection on the sacral facet is an elongated depression or groove, which passes along the centre of both limbs of the auricular surface, and re- ceives a 'reciprocal elevation on tlie iliac articular surface (fig. 89./) Now this ridge on the iliac surface evidently bites in its turn on the sacrum, and presents another obstacle to anterior displacement in the superior limb, as well as to downward displacement at the inferior limb. The surfaces thus ajjplied to each other, being so curved, give a greater extent of ajiposition than if they were plane, and, at the same time that they allow of a limited yielding of the sacrum to pressure, keep the surfaces continually in contact. And we shall find that, although the general shape of the articular surface is rendered angular by the “joggle” b (fig. 88. a), the groove and corresponding iliac ridge form a regular cres- centic curve, or segment of a circle d,f e, of which, in fact, the central internal projec- tion of the tuberosity of the ilium above at a is the centre. Now it is to this prominence that the powerful deep posterior and interos- seous sacro-iliac ligaments are mainly fixed above ; and it is by being suspended by and moving on them in the radius a,f, that the sacrum slides on the ilia downwards and back- wards in the direction of this groove on the reception of force from above. That this motion, though limited, does take place, and in this direction, may very readil}' be proved, on the detached pelvis, by striking directly dowmwards on the upper extremity of three or four lumbar vertebras cut off' with it. The impulse wdll be almost entirely felt at the tip of the coccyx, in a direction upwards and backwards. That portion of it which is directed immediately downwards is checked by the powerful liga- ments above mentioned, and is but little felt at the sacral promontory. If a section of the whole pelvis, in the direction of the cotylo-sacral arch is made, as in the next figure, a very important element in the mechanism of the sacro-iliac articula- tion is brought to view ; viz., the deep pos- terior and interosseous sacro-iliac ligaments, (d, e.) These ligaments are continuous one into the other, becoming shorter dowmw'ards, as the distance between the bones becomes less. They narrow also antero-posteriorly, so as finally to be received into the retiring angle formed by the limbs of the articular facet, at which point they are seen in the transverse section in the sacral axis in fig. 88. b, f. They are attached, externally, to the central Ut PELVIS. prominence on the inner surface of tlie iliac backwards, and are curved also a little out- tuberosities, which project ujjwards and wards, the better to resist inw'ard traction, Fig. 89. Section of the pelvis and heads of the thitjh hones, made in the direction of the coti/lo-sacral arch, a little helow the pelvic hrun ; showing the iiiitero-iiosterior Scieral wedge, the suspending oliice and oblique direction of the posterior sacro-iliac ligaments, and tlie wavy section of the joint, a, iliac tuberosities; b, c, antoro-posterior sacral wedge; d, deep posterior sacro-iliac ligaments; e, interosseous ligaments; f, auricular groove; c, sacral joggle; g, c, cotylo- sacral rib. (Drawing made from a recent section.) following the lesser curve of the iliac crest. This thickened central portion of the tubero- sities is placed above the angle of the articidar facet, in the line of direction of the cotylo- sacral arch produced u|)wards through it. In the accompanying figure, the section, made al- most in the plane of the [lelvic brim, cuts di- rectly through it. Passing downwarils and in- wards, the powerful fibres of these ligaments are attached to the upper external part of the posterior surface of the sacrum, 6; and they suspend the sacrum between them some- what in the manner of a suspension bridge, of which the iliac tuberosities are the sus- pending buttresses. This arrangement evi- dently considerably adds to the yielding elas- ticity of the sacro-iliac joint, and does much to lessen the concussions passing through it. It is evident also that it is in these ligaments that the most powerful preven- tive to anterior and downward displacement of the sacrum resides; for this coidd not take place without absolute rupture of their numerous fibres, resisting, as they do, all motion of the sacrum, except, in the limited sweep of the radii they form, a motion which exactly coincides with the movement of the sa- crum proved by the experiment justmentioned. But these ligaments, from their oblique direction inwards, at the same time that they resist downward pressure, pull with a corresponding force the sacrum and the ilia more closely together, and render, by this constantly tightening and bracing process, all the before-mentioned provisions for resisting displacement more effective, and, by a gradu- ally increasing resistance, overcome the impel- ling foi'ce. To illustrate this effect, it may be mentioned that the effect of placing too much weight on the crown of an artificial arch is to cause the line of [iressure (c, a, c,Jig. 90. a), which ought to pass through the centres of the “ voussoirs ” perpendicular to their joints, to rise above the “ extrados” at the apex, a, and to be brought within the inner surface or “ intrudos" of the arch, b, on each side; and this causes the voussoirs, a d, d c, to turn on each other at the edges nearest the line of pressure ; and in consequence the crown of the arch sinks and opens below, b. PELVIS. 145 and the haunches rise and open above, d, d. the sacrum with regard to the ilia, forces The sacro-iliac joints, being the haunches of acting on the lumbar vertebrte have a ten- dency to throw the base or sacral promon- Fig. 90. tory downwards, and to tilt the apex with the A, diagram of a yielding arch, a, extrados; b, in- trades ; d, d>, the haunches ; c, a, c, dotted line of pressure. Ti, parallelogram of forces of sacro-iliac posterior deep ligaments. a, c, vertical or sustaining force ; c, d, lateral or tightening force ; h, c, diagonal direction of ligaments. the cotylo-sacral arch, have in like manner a tendency to separate, above and behind when the pressure on the sacrum is increased ; and this tendency is counteracted by the strong posterior sacro-iliac ligaments. By the law of the resolution of forces, this tightening ac- tion of the sacro-iliac ligaments may be ex- pressed by the opposite sides, a b, c rf, of a parallelogram {fig. b), of which the line of direction of the ligaments, h, c, forms the dia- gonal, and the remaining sides, a c, h d, the sustaining power. Lastly. Because of the oblique position of coccyx upwards, as is seen in the experiment of striking the separated extremity of the lumbar vertebrm before alluded to, by the im- pulse felt at the sacral promontory. It will be better understood by reference to the drawing and diagram of a model made to re- present the action {fig. 91. a. and b). The tendency of the saenun is to timi round the axis of the sacro-iliac joints in the curve d f e, {fig.SQ. A.), and round the centre a {fig. 91. o'). To counteract this tendency of the base downwards and forwards, the strong ilio-lumbar ligaments {a) pass backwards and outwards from the last lumbar vertebra to the crest of the ilium, upon which it obtains a long and broad hold. And to resist the tilting upwards of the apex of the sacrum, are attached the extremely powerful sacro-sciatic ligaments {b), which aid also the oblique sacro-iliac ligaments to resist backward displacement. Thus are constituted two strong yet elastic springs on each side acting upon the con- cavities of the lumbar and sacral curves, which have, perhaps, the most powerful influence of any that have been before mentioned, in breaking the force of shocks and concussions passing along the bones of the trunk and lower extremities. The importance of this office of the sacro-sciatic ligaments is seen in their great strength, and in the consolidation of the lower sacral vertebree to which they are attached. The forward direction of the base of the sacral wedge when taken antero- posteriorly, as seen by looking from above, facilitates this elastic yielding of the sacral spring, as it evidently could not take place if Fig. 91. 'ii, vertical section of the os innominatuin, with the sacrum and ligaments attached, in oi tha • ischio-sacral support, a, ilio-liunbar ligament ; b, saci'O-sciatic ligaments ; c, iliac tuberosity. (Drawm ' from a recent section.) B, model of the mechanism of the same structures, c', d represents tlie yielding motion of the po.sterior ' deep sacro-iliac ligaments. Snpp. L HG PELVIS. the double sacral wedge had a small diameter directed forwards as well as dmvmvnrds, in which case it would be prevented by the ilia from moving in that direction at all. Thus the pelvic supports of the trunk are a peculiar and admirable combination of the arch and the suspension bridge. Untler heavy weights, the preparatory tension of the pelvic muscles, as the psom, pyriformes, and great glutei, will, by more closely apjtroximating the sacrum and ilia, produce the conditions of the arch. But in sudden shocks, the strain will fall more immediately upon the ligamentous suspensory structures, as the sacro-iliac, sacro- scialic, and ilio-lumbar ligaments, more calcu- lated, by their resiliency, to break their force gradually, and finally overcome them. The thick, strong, and elastic fibro-cartilagin- ous pads inserted between the opposing os- seous surfaces of the sacro-iliac ami pubic symphyses may be mentioned also, as con- tributing to deaden and break the force of shocks passing through the pelvic arches; and these being generally, as we have seen, arranged in two layers allowing of limited sliiling motion between them, are better calculated to resist sudden shocks passing obUquehj than single discs, such as the vertebral, which are chiefly disposed to rci,Ki 'pressure passing directly. The posterior projection of the iliac tubero- sities protects the sacrum, deeply situated be- tween them, from direct force tending to produce anterior dislocation, while their in- ternal direction prevents that bone from slip- ping backward between them. The great breadth and size of the sacrum in the human pelvis — it being proportionally than that of any other animal — indi- cate its importance as the basis of support to the spine, and the crown of tiie pelvic arch ; and, in connection with the admirable mecha- nical and architectural arrangements just de- scribed, present a wide contrast to the pelvic structures of aniTiials ; and prove the erect position to have been designed for the habi- tual expression of the dignity of man. The thigh of man, when stauiling, forms one line with the trunk, and makes an obtuse angle with the posterior arm of the pelvic lever; but in quadrupeds it is directed much more for- wards, and forms an acute angle with both the ilia and the spine. In quadrupeds, the thighs are much closer together and more prcssetl upon the flanks, and, even when they rest on their haunches, they naturally support themselves on their fore legs. This is even seen to a great extent in the apes and monkeys, so difficult is it for them to maintain the centre of gravity in an erect posture. The extensors and flexors of the thigh on the pelvis are also more developed in man, in order to sustain with more firmness the erect posture. Hence the greater breadth of the hip and buttock, and the bulk of the thigh. The breadth of the pelvis also gives a greater leverage to these powerful muscles. In w'alking, the human pelvis is thrown alternately, on each side, upwards, forwards, and sideways, as the leg on that side is lifted ; the trunk keeping its centre of gravity over the bearing leg by swaying regularly to that side, the pelvic hoop being at the same time drawn over the supporting leg by the powerful abducting muscles, the glutei. On account of the greater width of the pelvis and trochanters in the female, the centre of gravity oscillates through a greater sjiace, and takes longer time to pass over from one leg to the other, and hence the greater amount of undulation in their gait, especially when running. Mechanism of the human pelvis in regard to qiarturition. — As a containing cavitj', when completed by its muscular and fascial struc- tures, the pelvis offers a basin-shaped struc- ture with a somewhat triangular superior aperture, the sides of which are formed by the psoae muscles, and the base by the pubes ; and with a moveable floor, formed by fasciae and the levator ani muscle, and perforated by the rectum and generative organs. Its walls are interrupted laterally by the sacro-sciatic and obturator foramina, wdiich are filled by soft and yielding muscular and ligamentous struc- tures, and give way considerably to |)ressure from within, enlarging the pelvic diameters opposite to them. They afford, in common with the superior and inferior openings, the outlets for the nerves and vessels passing from the lumbar and sacral plexuses and iliac trunks to the inferior extremities and peri- neum. The inferior outlet also transmits the external communications of the pelvic viscera. These are, the bladder supported by the pubis ; the rectum, supported by the sacrum and coccyx ; and the internal organs of gene- ration placed between them. In the female these internal organs are more bulky than in the male, and consist of the uterus ami its ovarian and vaginal appendages. That there is a relation between the greater size and the functions of these organs, and the greater extent of the female diameters, is evident from the consideration of their simul- taneous ilevelopment at the period of puberty, and corresponding increase afterwards. This lelative development of the pekis seems to extenil not only to sex, but to the varieties of mankind, either as an irrespective consequence of primitive formative type, or in regard to the adaptability of the foetal head to the pelvis in the processes of parturition. In either case this adaptation is strikingly illus- trated by the different pelvic forms prevailing in different races of men, which will be found, when considering that branch of our subject, to be markedly assimilated to the form of the skull. The pelvic bone, which is of the greatest importance in an obstetric point of view, entering as it does into the formation oi both the jielvic brim, cavity, and iiiferior outlet, is the ‘pubis; and deformities of this bone produce the greatest obstacles to par- turition. The sub-pubic arch is a peculiarity of the human species, it being only imper- fectly developed in the lower animals ; and it has an important bearing upon human par- PELVIS. 147 turition, in being compensatory for the great curve of the pelvic axis, and the change of direction forward of the inferior from the superior outlet. This curve is dependent upon, and follows the curve of, the sacro-coccygeal column, which, being more acute and di- rected more I'orwards below, affords the chief support in the earlier months of pregnancy to the uterus and its contents, which lie in the axis of the superior outlet, which axis, as we have seen, impinges below upon the coccygeal bone. Now, the coccyx, being principally held up in its forw'ard position by the elastic sciatic ligaments and by the resilient ischio- cocc3'geus and levator ani muscles, affords a resisting support which is at once powerful and yielding, and acts like an elastic spring in supporting the uterus and its delicate contents under the effects of accidental shock. The female cocc3'x is much more mobile at every age than the male, and when ankylosed to the sacrum it is less favourable both to pregnancy and labour. In the more advanced stages of pregnancy, however, the uterus rises into the abdominal cavit3', and rests mainly upon the smooth concave surfaces of the pubes and the soft muscular margins of the pelvic brim, being embraced and supported above and in front by the abdominal muscles. To allow the great expansion of the uterine contents, the broad ventral notch and expanding iliac wings are dispositions of great significance. During labour, the foetal head enters the brim of the pelvis in the oblique diameter, which being less encroached on by the muscles is the best adapted to receive it, as well as by its correspondence in form to the brim in that direction. Then traversing the pelvic axis, it passes, first downwards and backwards, and then, being turned forwards by’ the sacro- coccygeal curve, escapes under the pubic arch and through the inferior outlet. The foetal occiput is directed generally in the left oblique diameter, towards the left ilio-pubic junction (in 69 per cent, of the cases — Naegele — to 80 per cent. — Boivin), and in its progress is twisted gradually forwards and towards the median line by the impingement of the parietal protuberance upon the inclined plane of the pyriformis muscle and upon the projecting ischial spine, until it emerges under the sym- physis pubis, around which it turns vertically as round a centre ; the real centre of its motion, however, being, as we have before seen, a little in front of and below the pubis. The more anterior part of the foetal head, then, traversing the circumference of the sub- pubic circle, extends the coccyx, and passes between the tuber ischii, distending thesacro- sciatic ligaments and perineum, and turning, as it does so, on its own transverse axis. In a well-formed woman, according to Naegele, the superior plane of the pelvis will be horizontal when the trunk is between the sitting and recumbent positions (i. e. when it forms an angle of 30° with the horizon). In such a position traction on the head of the child should be perpendicular. In sustaining these evolutions, the pelvic circle necessarily is exposed to a force not hitherto considered, viz. pressure from within. In well-formed pelves this pressure will be exerted equally on all parts of the circum- ference, from the adaptation, before mentioned, of the child’s head to the form of the pelvis. The strain, however, will be most evidently exerted upon the ligaments of the and sacro-iliac st/mpli^ses. The question w'hether these ligaments yielded during labour sufficiently to enlarge materi- ally the diameters of the pelvis, is one which has attracted the attention of anatomists and obstetricians very much, particularly about the latter end of last century, when M. Sigault proposed, in lieu of the Ctesarian section, the section of the symphysis pubis, with a view of affording greater pelvic diameters. Among the older writers on this subject Mauriceau, Peu, Lamotte, Vesalius, Varan- dens, Menard, and Voigt denied that separa- tion of the pubic bones occurred during labour. Some believed it to occur only in young primiparous females ; others in primiparous females of advanced age ; and others again only in pelvic distortions or peculiar circum- stances of pregnancy. Ambrose Pare, Pineus, Bauhineus Eiveanus, Diemerbroek, Arniseus, Bianchi, Gregoire Pineau, Duvernay, Bertin, Levret, Santorini, Spigelius, and Smellie, have observed this se- paration in the dead parturient woman ; and Guillemeau, Hildanus, Van Solingen, Ves- lingius, Puzos, Soumain, Bikker, Arnauld, and Morgagni in the living subject. Pare and Peu asserted that they had seen cases where the ilia had been separated from the sacrum j and Smellie relates a case where great pain at the sacro. iliac joints rendered this probable. Of those who admit that relaxation of the ligaments and consequent separation do take place, Boivin, Louis, Severin, Pineau, and Meckel consider it to depend upon softening, thickening, and loosening of a single inter- pubic fibro-cartilage, and deposition of fluid in its meshes ; Meckel with Antoine Petit, deny- ing the frequent existence of a separation be- tween two plates of cartilage. ButTenon found, that although, in most cases, the inter-pubic fibro-cartilage was single in the male, in v\ oman it was generally double, and contained a slit or cavity, with no connecting fibrous tissue between the middle of the plates. And he found this to be the case in the young as well as the old, and before pregnancy as well as after ; sometimes the slit was capillary, but in one female, recently delivered, the cavity would admit the forefinger. In none of his examinations did he find any thickening, soften- ing, or la.xity of the fibro-cartilage itself, how- ever recent the accouchment, although the external investing ligaments of the joint were relaxed and elongated. He considers, that if in females where but one fibro-cartilaginous plate is present, separation of the bones occurs during labour, it must be by rupture of the fibres of the disc or its separation from the bone. It is, however, difficult to comprehend 148 PELVIS. why elongation of tliese fibres should not take place as well as of those of the investing liga- ments. Tenon also asserts, that he has observed relaxation of the pubic ligaments, even in the male, during life. Sandifort considered that in women who have borne many children the pelvic ligaments become permanently looser. In a female aged 79, dissected by Cruveilhier, the symphysis pubis was exceedingly moveable, the sub-pubic ligament had disappeared, and a fibrous capsule invested the joint. Stemmer- ring believes that separation of the pubes is not rare, even during easy labours, and that they remain permanently loose, and the pelvic diameters larger, after many labours. Ac- cording to the last author, the sacro-iliac joints have also been found separated by a cavity of the width of an inch in females who have died during parturition. But it is a (jiiestion, whether this was not caused by disease and deposit of pus. In a woman mentioned by Frank, in Textors Neuem. Chiron, (vol. i. p. 261.), the [telvis was so moveable every time she became ]>regnant, that she could not stand u[)right. Instances of separation of the pubic joint during labour are also mentioned by Eichclburg in liusl’s Mngfizinc (vol. xvii. part iii. p. 550.), and by Nicholson in Trans, of Physic, in Ireland (vol. iv. 1824). Dr. William Hunter, in his memoir upon this subject, gives two cases of parturient women, in which the fibrous tissue connecting the cartilages was replaced by a ca- vity lineil by a perfect synovial membrane, and forming a perfect arthrodial joint ; and he concludes, that a certain relaxation of the pelvic ligaments takes place in the latter months of [)regnanc3' and during labour, al- lowing of a slight increase of tlie pelvic ca- pacity, and a yielding to the shape of the foetal skull. On examining the pelves of five women who had diiul soon after delivery, Dr. Knox of Edinburgh' found, in all, a remarkable relaxa- tion of all the ligaments of the pelvic joints ; in one the bones could be made to slide over each other. This anatomist also inclines to the opinion that this process is a regular and healthy one in the parturient female. This opinion is also supported by the post-mortem researches of the celebrated Rokitansky of Vienna, who considers that, in parturient women, the jiclvic ligaments become soft, relaxed, and stretched. In addition to the testimony on this side of the cjuestion, M. Senoir read an essay on the “ Articnintions of the Female Pelvis,” at the Academy of Medicine of Paris, on the 1st of April, 1851 ; in which he concludes, 1st. That the articulations of the pelvis proper should not be considered as amphiarthroses, but as arthroses ; and, 2ndly. That analogy of structure and composition leads liim to thndc that an effusion of synovial fluid from the membrane lining the joints, causes the sepa- ration of the bones sometimes observed. (^Bulletin de I' Aradcmie Nation, de Medecine, t. xvi. No. l.'L April 15th, 1851.) It is, however, considered by Baudelocque, Boyer, Burns, Dewees, Denman, and I think most English writers on Obstetrics of the present day, that, in common cases, wo sensible relaxation of the pelvic ligaments takes place, and that, when such relaxation does occur, it should be rather considered in the light of a morbid condition, as it adds very little to the diameters, and is attended with severe in- conveniences from rupture of the sacro-iliac ligaments. Notwithstanding, comparative anatomtg par- ticularly in Cows, Seats and Guinea-pigs, to be presently considered, presents us with a strong analogical [troof in favour of the doc- trine of some parturient relaxation of the pelvic ligaments in women. CoMUAR.\TivE Anatomy of the Pelvis. — In the different races of mankind, the pelvis, as influencing in a very great degree the form of the body, presents considerable varieties. Camper, and afterwards Soemmerring, re- marked that Negroes hatl more slender loins ami hips than Europeans, consequent upon narrower pelves. Scemmerring gives a com- parative measurement of the diameters of the brim in a Negro and an European of adult size. In the Negro, he found 3 in. 1 11 lines, long or transverse diameter ; in the European, 4 in. 6 lines ; in the Negro the short or conjugate diameter was 3 in. 7i lines, and in the European, 3 in. 1 1 lines. From Cani|)er’s measurements, the long diameter was to the short one as 39 to 27i in an adult Negro, and as 41 to 27 in an adult European, who, nevertheless, was of much less stature than the Negro. The measurements in the table on page 151, were taken in the dissecting rooms of King’s College, from an adult male Negro C feet high. From the measurement of this pelvis, the antero-posterior diameters seem to pre- vail in the Negro, and the whole pelvis to be smaller than in the European. This is seen remarkably in the limited breadth of the sacrum, (3 in. 9 lines), and in the ap- proximation of the ischial spines (3 in.,) both much lower than the average European ; the latter, indeed, less than in the Chimpanzee. In fact, I have never met with an European sacrum so narrow as in the Negro above mentioned, especially in an individual so tall as 6 feet. This difference is remarkably contrasted in the pelvis of O’Byrne, the Irish giant, in the Hunterian Museum, in which the iliac wings are remarkably large in compa- rison with the true jiclvis, and the sacrum very broad. The superior pelvic outlet is in this skeleton disproportionately larger than the inferior, the ischiadic tuberosities being nearly as close together as in ordinary- sized pelves. This sudden narrowing of the pelvis has evident reference to the better sustaining of the viscera of the pelvis and ab- domen. It is supposed that in Negro women ge- nerally, from the easy labours they undergo. PELVIS. 149 there is much more proportionate pelvic ca- pacit}'.* The dimensions of the pelvis of a Negress of small stature, contained in Bonn’s Museum at Amsterdam, are given by Dr. Hull in his Second Letter to Simmonds, as follows; At the brim, the conjugate diameter, 4f inches ; the transverse, 4^ ; the oblique, also 4i inches. From the inner extremity of the superior pubic ramus, to the sacro-iliac joint >f the same side, 44 inches. At the oidlet, the an- tero-posterior diameter (measuring from the apex of the sacrum) was, 4 J- inches ; the transverse, 34 inches. The breadth of the sacrum was, 3J, inches, and the length the same. The angle of the sub-pubic arch measured only 6?4°- Ir> 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 SimicE. 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 Mi'. 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 laboui's are, on the contrary, “ry 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 d'ystochia IS not at all unfrequent even in the African iie- gresses. 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 theischia 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 die 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 ajjpearance to the sacro-sciatic notch. The posterior lateral parts of the sacrum are not unusually thickened, but the sacral spinous processes are well markeil 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 li'om 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 Collese Museum, however, the vulva seems to be placed unusually far back, which may pro- L 3 150 PELVIS. bahly depend upon great obliquity of the pelvis. The measurements of the Tahitian male pelvis, given in the table, corresponds, in the pro.xim.ity 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 shallowness of the true i)elvis. Otherwise, it is light and roomy, with well- expanded and very short ilia. The shape of the superior ojiening 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 neai ly related to the apes than the European, an examination of the adjoining table will show a very great pelvic difference between them and the highest apes, in the less proportionate [ireponderance of the antero-posterior over the transverse dia- meters, the shortness and expansion of the ilia, the less depth of the true jjelvis both in front, sides, and behind, and es|)ecially in the more marked sacro-vertebral angle. M. Vrolik describes the j)elvis of the Javanese as very light in structure, of small size, and of a characteristic circular form at the suiierior 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 diflerent races, Professor Weber reduced them to four principal forms, distinguished by the general shape of the pelvic openings. 1st. 2'he oval form. — The superior opening of an egg-shaped figure, narrow in fronf, 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- [lean 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., aiul 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. 2ml. 2'he 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, ami two Mestizos. 4th. 2'he 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 ap|>roach 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- cuudo ; 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 characteri.stic of race of any in the body, because of its great influence upon the shape of the trunk; and yet, from Weber’s researche.s, it would appear PELVIS. 151 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 e.Kclusive enough in its peculiarities to es- In the SimuB, and those even which most Comparative Pelvic Dimensions. II ^ X— - ’o 1 lu 8 E Negro (Male), Tahitian (Male). Bushman (Male) i fa 3 Adult Chimpanzci (Female), [-lunterian Museui Chimpanzee, (K. C. Museum. Adult Uran-Utar 3 s CJ c 3 Gibbon varia>, (Female.) (i)r. Knox.) •< 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 4 4f Antero-posterior - 4 1 4 0 3 3 4 6 5 9 5 6 5 0 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 i 3 9 4 0 2 9 3 0 Antero-posterior - 3 0 3 3 3 5 4 0 1 4 6 3 6 4 0 Between anterior superior iliac i spines - - - - - 8 6 8 6 7 3 8 3 5 6 11 0 4 0 Depth of true Pelvis- |io 0 Between sacral promontory and 1 tip of coccyx - - - 5 G 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 - 1 9 1 6 1 3 1 3 2 6 1 10 2 0 Depth of whole Pelvis. Between iliac crest and sciatic tuber : - - 8 0 7 0 7 6 10 9 9 0 9 6 5 Ah 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 Betw’een 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 1 3 0 2 3 3 3 Angles — Sacro-vertebral - _ 120° 11.5° 135° 158° 145^ 150° Pelvi-vertebral - - - - 145° 145° 140° Sub-pubic - - - - - - 60° 85° 90° 1 80° 60° 50° closely approach in osseous conformation the human race, as in the genera P'dhecus 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 Gibhon prevail greatly over the transverse ; that the dejHh 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 remarkabl}' 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 tlie 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. /g-9?-) ... This high position of the coccyx is owing partly to the shortness of the sacrum, which is composed of three large flat vertebras, 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 vertebras. 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(«) being placed directly over the cotyloid cavity ; and the crest (c) being, consequently, very short, terminating abrii|)tly at the vertical rib mentioned in the description of the human ilium. The (dec are more expanded in the Uran than the Chimpanzee. The crest does not present the lateral y-like curvature, and is less arched than in man. The anterior iliac spines are more widely separated, the inferior (h) 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 lluminants. The distance from the cotyloid to the sacro- iliac joint is 31 inches in the Hunterian Chim- panzee, and about 3 inches in the Uran, though, from the greater straiglitness 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 Simitc generally, the ilia are said to be jilaced 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 tlie same plane. I have, however, found the diu-vcrlebral angle in Chimpanzee, Uran, long- ar.med Gibbon, and brown Baboon to be very little, if at all greater than the human fdvi- vertebral, 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 siiine ; while in the Man- drill and many Monkeys they are almost pa- rallel. This characteristic, heightened by tliat 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. PeJvis of the adult Chimj^aixzee, ayiterior 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-kchicd 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 sjjines; 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 Shnice generally, may be more [)roperly called the iscliiu-jmbic 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 sntall, 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 pwics 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, formed by the su- perior ramus of the pubis with the cotylo- sacral arch of the ilium, is 120°, and in the Uran 123°; constituting a striking difference from the human pelvis, where the cotylo-sacral and [mbic 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 j)elves, and one which distinguishes them, as far as I have seen, universalli/, from the human species (see j>age 173. 112.2 — 13.). A remarkable consequence of this more horizontal direction of the'pubis in the Simue is the disappearance of the angle of the sympihysis, it being quite parallel with the spinal column. And this parallel jmsition 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 less 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, particularly in the glidd and gastrocnemii, the plumpness of which constitute the buttocks and calves charactei'istic 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- ' »r 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 Oraiigs ; but the cotyloid notch is present, though small, in the skeletons I have examined. In the Hylohatis 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 Jnwards. The cotyloid cavities are thus more widely separated, and the siqjerior 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 vertebra, 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 Callitkrix, Cercocebus, and Semnopilliecus 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 jnibes 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 Cercopithccus, or Baboon tribe, there is, in the brown Baboon, a well marked sacro-vertebral aTigle (155°) ; the two u[)per of the three sacral vertebrae only articulate with the ilia. The caudal vertebrm 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 are flattened, with an acute superior border, and rostrated at the symphysis. more marked ( 1 10°). In the Mandrill, Papio Alannon, 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, wdth much-expanded and flat tubers. The 2^^‘bes are at right angles, both to ilia and spine, and the ischio-pnbic 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 ; piu^cs 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 vertebras, except in the thicker transverse processes. Caudal vertebrre numerous. The pelvis generally is veiy weak, narrow, and short. The ilia 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-jnibic angle 120°. In Lj. 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; 2^uhes long, large, oblique, with no ilio-pectineal apo- physis; ischia short, with horizontal rami and tuherosities passing backward to articidate with the transverse |)rocesses of the iqjpcr cocc}'geal vertebra;, another bird-like arrange- ment. In L. indri the .s-«era/ [lieces are four, with complete ankylosis, the two or three iip|)er articulating with the ilia. 7//a expanded, with extended crest and external fossa, and reaching to the penultimate lumbar vertebra; ; ischia very short, w'ith more expaTideil tubers ; pubes less oblique. In L. vuluns, or Galco- pithccus, the sacrum has five vertebrae, the first only articulating with ilia. Ilia small and narrow ; ischia with lai'ge posterior angle; 2>ulnc si/nq^hijsis very short. In the sub- genus Stero2>s, the slender Loris presents a remarkably elongated and contracted pelvis. The sacrum is long and narrow, with the two up[)er pieces articulating with ilia. Ilia slender, long and columnar, and nearly parallel with spinal column ; ischia small, flattened laterally, jilaced in a line with the ilia, and very near each other, so that the cotyloid cavities are closely approximated ; the lateral diameters very short, Peh>is of the slender Loris, lateral view. The animals most allied to the preceding order of primates in the form of the pelvis, taken in conjunction with their general struc- ture, are the Carnivora. In these, as in most multidigital animals, the pelvis is so con- tracted that the trunk resembles an in- verted pyramid ; whereas in man, constructed for an erect |)osture, the base of the pyramid is in the pelvis. Climbing animals, such as the Apes, Bears, and Sloths, [iresent the nearest approach to the human structure in this particular. In estimating the sacro- and ilio-vertehral angles in the succeeding orders of Mammalia, it should be observed that, from the coin- cidence of the lumbar curve with the great dorsal curvature of the spinal column and the elevation of the neck, the vertebrae cannot be considered as being placed in one general plane, as in man. The line of direction of the lumbar vertebrae has, therefore, been taken for the sacral and iliac angles. The sacrum, in the Carnivora 94.), is narrow, flat, and triangular, with long and distinct spinous jn'oeesses, and placed almost in a right line with the spine. In the Bear, however, from its climbing habits, the sacrum is broader, larger, and more massy, and the sacro-vertebral angle more marked. The number of sacral vertebrae is three in the great majority of the species, the two upper articulating with the ilia ; but in the Hyaena there are but two, in the Tiger four, in the brovvn Bear five, and in the white Bear as many as seven. The coccygeal or caudal ver- tebrae {b ) are generally very numerous. The ilia arc moderately long, thick, and narrow in their whole extent, and are placed very obliquely upon the lumbar vertebrae, forming with them an angle of about 150° to 160° ; but in the Bear and Hyaena 140° only. The external surface of the elongated iliac wing is concave, and the internal flat and turned inwards towards the spine ; the crest (c) thick, narrow, acutely arched, and pro- jecting backwards beyond the spinal column. The ischia are long, strong, prismatic, some- what expanded posteriorly, and considerably divergent, but dii’ected in the same anlero- 2)osterior 2>lane with the ilia, forming toge- ther a very long ilio-ischion element. This disappearance of the antero-posterior, ilio- ischial angle, which commenced in the Apes, is, in the Carnivora, arrived at its greatest extent, and in the Tiger is even reversed or bent downwards in the opposite direc- tion about 15° (see Jig. 112. 5). With the great obliquity of the ilia, this affords, in the quadruped position, a longer and more power- tul leverage for the muscles of the hinder extremities to execute their characteristic bounds, and, like the reverse formation of the ilio-pubic angle, it is another great distinction between these and human pelves. The ischial tuberosities (e) have an outward direction, as well as the ischia generally, and the spine (g) is a mere rudimentary ridge. They;«5e« are short, and the symphysis (/’) is long, being formed generall^f both by the ischium and pubis. The ilio-2mbic angle varies from 110° in the Tiger, to 120° in the Lion and Leopard, and 125° in the Bear and Hyaena. The anterior pelvic outlet is smaller than the posterior, from the divergence of the ischia pos- teriorly ; and the cotyloid cavities are inclined outwards slightly, so as to overhang the femora in the prone position. The centre of gravity, in these animals, being placed much nearer the anterior than the posterior extremities, the former bear the most of the weight, while the latter act more as impelling agents in the powerful bounds which they execute. The ilia of the Bear are shorter, thicker, and more massive, with more expanded wing.s, a better-marked anterior superior spine, and a more marked lumbo-iliac angle ; the ischia short and widely expanded, and the 2^tibes remark- ably strong, with a very long sympliysis. At Fig. 93. and the inferior outlet a mere chink. The 2~>td}es 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 ])ortion with the iliac, the iUo-2nihic angle being 75°, or less than a right angle, the only instance of the kind I have met with. {See Jig. 93. a, b, c.). PELVIS. 15.5 the anterior pelvic outlet, the transverse dia- meter is a little larger than the antero-pos- E’ig. 9I. Pelvis of the Lion, side view. terior, and the acetabula are large and deep. In the Badger the ilia and ischia are large, expanded, and curved outwards at their free extremities. The iliac shaft is prismatic, with an ilio-liimbar angle of 140°. The piihes are rather long, with an elongated symphysis, and form an angle with the ilia of about 130°. The same general conformation is evident in the Racoons and Coatis, the ilio-ischial angle being, however, somewhat better marked, and the ilio- pubic about 145°. The Coatis have but one sacral vertebra. In the H}sena, also, the iliac wings are considerably spread, with a very pointed anterior spine. In the Dingo the ischio-pubic element is very short, the anterior outlet and obturator foramina small, but the posterior outlet larger. The Weasel has a very small pelvis, with but two sacral vertebrae, one only articulating with upper extremities of the long iliac shafts. In the PhoccE the samnn has four vertebrae, the first only articulating with ilia, and much wider in its transverse processes than the rest ; the ilia are extremely short, thick, and curved outwards, with very small external fossae ; the isckia are long and slender, with small tuberosi- ties almost touching the second coccygeal ver- tebra, with long rami not forming a symphysis, but directed backward to meet the pubis. The jmbes are very long, slender, and oblique, with a short symphysis, and including a very large, oval obturator foramen. The pelvis altogether somewhat resembles that of the Badger, with the superior opening much elongated antero- posteriorly, and triangular in shape, with the base at the sacrum. The shortness of the ilia alone indicates the great contraction of the posterior extremities for their swimming re- quirements. Dr. Knox has observed, in a pregnant female Seal, a separation of the symphysis pubis, and elongation of its liga- ments to the extent of nearly 2 inches, such as Le Gallois has described in the Guinea-pig. He found, moreover, that such a separation I of the bones produced much more enlarge- ; ment of diameters in these elongated trian- gular pelves than in the transverse oval form ' of the human female. In the order of pelvic development, the Pachpdermala occupy a very high place, being characterised by great massiveness, propor- tionate shallowness, and perpendicularity of pelvis, and large and overhanging acetabula, the better to support the immense weight of these animals, thrown more on tlie hinder ex- tremities than in the Carnivora, from their bulky dorsal structures and abdominal vis- cera. The ischial spinous ridges and anterior inferior iliac spines are faintly marked or wanting, the sacral spines are coalesced into a continuous crest, and there is little or no sacral promontory. The sacrum of the Elephant (Jig. 95.) is comparatively very narrow, flat, and short, and placed on the spine at an angle almost imperceptible ; the number of vertebrae being four only, according to Cuvier. The coccygeal vertebrae are numerous. The ilia are short, broad, massy, fan- shaped, and much expanded, with a large concavity or iliac fossa directed forwards and downwards, the dorsum being alter- nately concave and convex. The iliac crest (c) is large and flat-arched, with the anterior su- perior spine (a) hooked suddenl}' downwards, and the posterior inferior directed backward from the sacro-iliac joint, to afford leverage to the powerful sacro-iliac ligament. There are no well-marked iliac ribs, except the cotylo- sacral (d), which is very strong and massy. The ischia are moderately short, and form an ilio-ischial angle about 14-5°, presenting no spine, and having the tuberosities (e) directed Fig. 95. dorsally, and the rami (/) vertically towards the abclominal surface. The pubes are short, and directed almost horizontally inwards, with a well-marked ilio-pectineal spine (li). The symphysis (g) is parallel to the vertebrte, and very long, including the whole of the short ischial rami as far as the rough por- tion forming the tuberosity, so that the ischio-pubic symphysis extends as far back- wards as the tuberosities. The sciatic notches are wide and open, but the obturator foramina are smaller than the cotyloid fossae, which are very large and overhang much at the superior or dorsal part. The planes of the acetabula 15G PELVIS. are inclined from the perpendicular about 70° in the elephant, being about 5° more than in the fossil Megatherium and Mylodon. The pelvis of the Elephant is altogether remarkable for its perpendicular position, the lumho- iliac angle being about 120° only, and the pubes being advanced as far forward as the iliac crest, at an angle of 100° with the ilia. Thus the jiosterior limbs are brought more under the weight of the animal. The superior outlet is roundish, but broader at the [)ubes than at the sacrum, and the antcro-posterior diameter is but little larger than the trans- verse. In the fossil Elephant, however, the antero-posterior diameter is greater in pro- portion. The female Eleijhant has the pelvis more open than the male, and the borders more trenchant, according to Cuvier. Blumen- bach states that the round ligament, as well as the cotyloid depression, is wanting in the Elephant. The pelvis of the fossil Mastodon is much less depressed and expanded than that of the Elephant, according to Cuvier, and its outlets smaller, showing that its abdomen was of less size. The Rhinoceros has four sacral vertebrae, three articulating with the ilia, and supported by articulation with last lumbar transverse processes ; and the caudal vertebree numerous. The ilia are large, massy, short, and ex- panded, though much less so than in the Elephant ; with the anterior iliac fossa well marked, and the dorsum also generally con- cave from side to side, from the backward curvature of the inner border to be applied to the sacrum. The crest is large, and the anterior superior spine turned forwards, as in the Elephant, and forked at the end. The ischia are longer than in the Ele[)hant, with thick tuberosities, turned much outwards. Pubes long, and united at a sharper angle, with prominent ischio-pubic symphysis. The lumbo-iliac angle in the two-horned' variety is 125°, the ilio-iscitial 145°, and the ilio- ‘puhic 150°, making the pubis nearly at right angles to the spine. The whole pelvis is shallow, with the ischio-pubic portion placed more backward than in the Elephant. The anterior outlet is large and oval, with the longer diameter antero-posterior. In the fossil variety there is no fork on the anterior su[)erior iliac spine, and the obturator fora- mina are more elongated. In the Hippopotamus thesacrum is very broad and flat from side to side, though arched con- siderably longitudinally ; with a considerable angle, and articulated with last lumbar trans- verse processes. The iliac wings are almost plane with it, forming a lumbo-iliac angle of about 150°, and are less expanded, smaller, and more slightly convex, with the two su- perior spines directed much dorsally, espe- cially the posterior. The ischia are long and comparatively slender, and directed dorsally, forming a large angle with the ilia, and sup- porting large and massy tuberosities, which are parallel to each other, and project by a prominent tubercle dorsally above the coccy- geal vertebrae, a peculiarity which causes this pelvis to look altogether like that of the Ox. The pubes are elongated, and the ischio-pubic symphysis also long. The obturator foramen is large, and the plane of the acetabulum looks downwards and outwards, and is placed at an angle of about 50° from the perpen- dicular, being 20° less than that of the Ele- phant. The whole pelvis has an open, light, oblique, and flat appearance, with the ischio- pubic portion placed more backwards than either the Elephant or Rhinoceros. In the Hog the sacricm is narrow, the ilia and ischia more elongated, and the latter closer to each other, with prominent and parallel tuberosities. The whole [jelvis is elongated and approaches the Carnivora type, as is particu- larly seen in the iVio-piiUc angle (120°). The lumbo-iliac angle is about 145°. In the Tapir are three sacral vertebrae, the two upper articulating with ilia, and forming a sacrum arched considerably, both transversely and longitudinally, and with an imperceptible angle. Theilia are remarkable for their long and somewhat rounded shafts, and the sudden ex- pansion of the wings on each side, so as to form a T shape, of which the branches are directed obliquely antero-posteriorly, the posterior branch being articulated to the sacrum, into which they bite well. The crest is thus made slightly concave instead of convex. The sacro- iliac facet, which in most mammalia is lunated in shape, with the convexity directed to the acetabulum, and the concavity to the spinal column, is in the Tapir of a peculiar shape, narrowing suddenly between the two sacral vertebra, and then again expanding, forming two distinct sacral “ joggles.” The ischia are long, with tubers projecting dorsally ; pubes directed inwards. The lumbo-iliac angle is comparatively very acute (125°) ; the ilio- puhic large (14.5°); and the ilio-ischial well pronounced ( 140°). The whole pelvis is very like that of the Horse, but is distinguished by the greater breadth and curves of sacrum, and by more massy proportions, and more distinct T-shaped, and greater expansion of the ilia. The pelvis of the fossil Paleotheriurn has some resemblance to that of the Tapir, but the ilia are longer and more prismatic, and the ischial tuberosities less developed. That of the Anoplolherium is a link between the Tapir and Camel. The Solidungula form a connecting pelvic link between the foregoing and the Rumi- nants. The sacrum of the Horse is flat, not curved longitudinally so much as in Ruminants, and placed in the line of the dorsal curve. It is moderately broad between the ilia, but narrows suddenly posteriorly, and reaches as far backwards as the middle of the ischia. This is the same position as in the Pachyderms proper; but in the Ruminants, whose pelves are more oblique, the sacrum scarcely reaches to the symphysis pubis, as is seen in the pelvis of the Ox {fig. 97.). The sacral pieces are six in number, two only articulating with the ilia, and the sacral spines PELVIS. are not united in a crest. The ilia approach in shape to those of the Tapir, being in a less marked degree T-sliaped ; the posterior limb of the iliac wings projecting inwards as far as the sacral spines ; the anterior superior spine often presenting an epiphysis, and the shaft being long and blade-like. The ischia are comparatively long, and much more slender than in the Ruminants, being placed nearly parallel with the coccygeal vertebra, and with [)rolonged tuberosities. The pubes are small and short, and directed a little forwards, as well as downward and inward, with a marked ilio-pectineal eminence, and a very long ischio- pubic symph3'sis. The sciatic notch is wide, and the obturator foramen small. The an- terior outlet is large and squarish, and the posterior eigngated vertically and somewhat diamond shaped. Lumbo-iliac angle rather larger than that of the Tapir, being about 1.30°; ilio-iscliial, 145°; ?md. the ilio-pubic about 130°; making the lumbo^ubic rather less than a right angle. In the Rumhiantia the samiin is composed generally of four vertebrae, the two upper articulating with the ilia. In the Gazelle and Antelope, however, there are five, and in the common Stag only three. The sacrum is pro- portionably broad, and more arched, both longitudinally and laterally, than in the pre- ceding orders. The sacral promontory is also better marked, and the sacro-lumbar angle more perceptible. In the Ox, especially, this reaches to about 145° to 150°, and in the Fallow-deer 160°. The sacral spines are coalesced in a perfect crest in the ()x. Fallow-deer, and Stag (yfg. 96. e), and partially in the gigantic Irish deer. Gnu, and Equine antelope ; not so in the Giraffe and Camel. The caudal vertebrm are numerous. The ilia are long, with the crest (c) concave, and the aim expanding laterally at the top, especially in the heavier Ruminants ; being concave internail}', and convex externally, and projecting much over the dorsal surface of the spinal column, by the flattened and elongated posterior superior spine (b). They form little of the abdominal parietes, and are placed on the spine at an angle of 140° to 150°. The ischia are long and large, and placed on the ilia at an angle (c d e) of about 150° in the Deer and Sheep tribes, but much less in the heavier animals. This in- creased length and size of the ischia is jiarti- cularly marked in the Deer tribe ; and, as fulfilling the same mechanical requirements for affording a long and strong hold for the power- ful extensor group of pelvic muscles, allies them with the Carnivora, and other springing animals afterwards to be considered. The large and flattened tuberosities (e) project much on the dorsal surface of the pelvis. This is especially seen in the Fallow- deer, common Stag, and Ox, with a well- marked lateral tubercle (g), which is also pre- sent in the Gazelle and Roebuck. They present no ischial spine, except in the Lama, where it is well marked. The pubes are very short and slender, and are directed from with- 157 out almost directly inwards, forming an ilio- pubic angle of about 130° to 140°. The Fig. 96. ilio-pectineal spine is much marked in Red deer. Generally the ischia form part of the elongated symphysis (/). In the 0.x, the spmphysis is not placed quite parallel to the spine, as is usually the case in the inferior animals ; but is placed obliquelj/, as in the human species, diverging more from the spine at the anterior than at the- posterior extremity, and forming with it an angle of about 20°, and causing the anterior opening to be larger than the posterior (see Jig. 97./). The anterior opening is large and roundish, with a prevalence of the antero-posterior diameter. The posterior opening is more square, but irregular and looking much up- wards. The ischio-pubic portion of the pelvis is altogether very long, and opposed to the coc- cygeal vertebrae. In Deer, Goats, and Ru- minants generally, but especially in the Ox, the gradual upward curve of. the ischia, and the well-marked dorsal projection of their tuberosities, cause them to appear promi- nently on the rump, projecting on each side and above the coccygeal vertebrae (/gs. 96, and 97. e.) In the Ox the itio-iscliial angle is as much as 130°; and the lumbo-iliac angle hemg about 150°, the acetabula are thereby placed directly under the last bone of the sacrum, and at the apex of an inverted arch (c d e) formed by the ischium and ilium. B}’ this elevation of the ischia, the sacro-sciatic ligaments become a means of support to the sacrum, as well as the sacro-iliac, and thus that bone becomes suspended between two curved springs, formed by the ilio-ischion on each side. Thus in these animals the sacro-sciatic liga- ments resist motion of the sacrum in a di- rection downwards anil forwards, a direction totally contrary to those of the human pelvis, as considered in the section relating to the mechanism of that structure. And this change of function, so simply transitionary, results from the alteration of mechanical require- ments in the quadrupedal position of the trunk. About the period of parturition, the sacrum of the Ox is said to sink evidently between the ilia and ischial tuberosities, by relaxation of these ligaments. The elevation of the ischial tuberosities doubtless would 158 PELVIS. make such a change of position more evident in the Ox tlian in other domestic animals. Fig. 97. Pelvis of the O.r, showing the ilio-ischiid angle (c d e). It is somewhat interesting, that, in most animals with flat sacral hones, tlie axes of the anterior and posterior [lelvic openings, as well as tliat of the tnbniar cavity, coinciile in the same straight line. In the Cow, however, and in some other Ruminants, these axes form a considerable angle one with the other, on ac- count of the greater curve of the sacrum. This will, doulitless, have considerable in- fluence in producing the more lahorious par- turition of these animals, which usually re- (juires artificial a.ssistance. In tlie Ox the planes of the acetabula are inclined about 40'^ from the perpendicular. The pelvis of the gigantic Irish deer also presents markedly this arrangement. In the American elk, the pelvis is rather elongated and narrow, being small and weak in comparison with the rest of the skeleton. There is the dorsal projection of ischial tuberosities; and the ischio-pubic symphysis is long, and diverges slightly from the spine posteriori !/. In the Camel the sacro-vertebral angle is well marked ; the sacrum is much curved, and composed of four pieces. The ilia are long, strong, and blade-like, with the anterior spine prolonged downwards and the ala? convex anterioidy. The ischia are compa- ratively very short and feeble, set at a larger angle on the ilia, and present a feebly marked spinal ridge, and a well-marked outward projection at the tuberosities. The piihes are broail and moderately long, with a better markcil ilio-pubic an'^le (I -20°) than in the preceding, and the ischio-pubic symphysis is long and divergent anteriorly from the spine, as in the Ox, the centre being opposite the last sacral bone. The foramen obturatorinin is small, and the anterior outlet large and oval. The lumbo-iliac angle is about 140°, and the lumbo-pubic is rather less than a right angle. In the Giraffe the sacrum is narrow, and its angle with the spine indistinct. The ilia are not very long, and the crest, unlike most Ruminants, is convex instead of concave, the wings being expaniled and concave in- ternally. The ischia are long and curved upwards, with everted and laterally flattened tuberosities. The pubes short and very thick, with long symphysis, forming a thick tube- rosity, and much diverging from spinal column anteriorly. Ilio-pubic angle large, 140° ; lumbo-ilinc, 1 50°. In Sheep and Goats the sacrum is broad, and its angle indistinct. The ilia are long and blade-like, with scanty wings; lumbo-iliac angle, 145°. Ischia broad and short, with large later- ally projecting tuberosities ; and a rudimentary s[)ine in the Ram. The pubes are longer than in Deer, and directed horizontally inwards. The pelvic outlets are large, as also arc the sacro-vertebral and ilio-ischial angles. A very distinctive pelvic peculiarity is seen in the Mcminna, or Pigmy Chevrotain. The ilia and ischia are, in this curious animal, anicpiosed to the sacral vertebrae. The osseous ridges in the site of the oblique posterior ilio-sacral ligaments are very prominent, and the ossified sacro-sciatic ligaments are distinct and well marked. The sciatic notch is thus converted into a foramen, and the pelvis re- sembles in this respect that of the Sloth. In the Musk Deer, also, the last sacral transverse processes nearly abut on the short and dorsally j)rojecting ischia. In the heavier Ruminants, as the Camel, gigantic Deer, and Ox, the pelvis has somewliat of the heavy appearance and overhanging acetabula of the Pachyderms, but in the lighter Deer and Goats it becomes gra- dually more slender and elegant in form, and nx're oblique in direction. In the Rodentia, the pelvis is largely de- veloped for the support of the powerful hinder extremities in leaping, the most usual mode of progression of the generality of these animals. The sacrum is generally continued in a line with the lumbar curve in the long-tailed species. In Hares and Rabbits, however, the sacrum is considerably arched, longitudinally as well as transversely {fig. 98. a), and its angle with the spine marked 160°. There are generally four sacral vertebrae, but the first is much larger than the others, especially in its lateral masses (5), to articulate with the ilia. Tlie Rabbit and Jerboa, however, present only two; and the common Rat and Beaver three; while the number in the Marmot is as many as six. The spines are not coalesced except in some Rats. The caudal vertebrae are more or less numerous, and are remarkable in the Beaver for the great length of the transverse processes and anterior spines, for muscular hold on this its useful appendage. In the Squirrel and Jerboa also, the tail is long and strong, and in the habitual sitting posture of these animals it forms, with the ischia, the third leg of a tripod, on which the body is sustained. In the short-tailed Rodents, the caudal ver- tebrae are curved dorsally, in an opposite di- rection to the coccygeal bones in Man and the Simice. The ilia are long, prismatic, and slender in the shaft, having a central ridge passing up- wards from the cotyloid cavity, with a groove on each side of it externally, and continued forward into elongated alae, little more ex- PELVIS. 159 |)ancled than the shaft in most of the order. They form with the spine an angle of about Fig. 98. 165° in the Hare, and 150° in the Porcupine. In the Copyrus, Hats, Mice, and Guinea-pig, they are nearly parallel with the spine ; but in the Jerboa they cross the spine at an angle much less than in others, being about 140°. In the Jerboa the iliac wings are curved out- wards superiorly and projected much on the dorsum of the spine, reaching beyond the elongated spines of the last lumbar vertebra. The ilia of the Beaver, and, in a less degree, in the Hare, are expanded, with prolonged and irregularly' curved crests (c), a little everted at the spinous processes (g), anil propor- tionally short in the shaft. The ischia in Rodents are generally long, especially in the Beaver and Jerboa. In the latter animal they are directed much outwards, with tuberosities large, much expanded, and everted posteriorly, to give firm attachment to the strong sacro- sciatic ligaments. They are placed in a riglit line with the ilia, the ilio-ischial angle being wanting as in the Carnivora {see fig. 112. 8.). In the Hare the tuljerosities of the ischia are large, and present well-marked lateral pro- cesses (e), which are everted, and rise above the level of the coccygeal vertebrae. Thejoubes are long and slender, and generally join with the ischia in a long median sympliysis projecting in a sharp, anterior, vertical, ridge (/); except in the Porcupines, Rats, and Mice, which have a short sym[)hysis pubis. In the Jerboa there is a slight pubic s2}inous process, very externally placed ; this is better marked in Hares (d). Rabbits, and Beavers. Tlie ilio- pubic angle in Hares and Rabbits is about 120° to 130°. In the Jerboa it is more oblique, 145° ; and still more so in Rats and Mice, 150°. The sciatic notch is generally long and nar- row, especially in the Jerboa; and the obturator foramen very large, particularly in the Beaver. The pelvic cavity and outlets are large and capacious, especially in the Jerboa, in which, by the outward direction of the ischia, the poste- rior outlet is much larger than the anterior. In the Beaver also the transverse pelvic diameter is large, and separates widely the hinder e.x- tremities of these animals, to aid their swim- ming habits. In the Capybara however, the pelvis is of little ca[)acity. In the Guinea-pig it is compressed so much laterally, that the anterior opening is of a triangular shape, with the apex at the pubic symphysis. According to Le Gallois, it measures only 1 1 millimetres transversely in a full-grown female, while the foetal head measures 20 millimetres across. Three weeks before labour begins, the elastic liga- ment uniting the symphysis pubis becomes thick, soft, and moveable; and eight to ten days before, the pubes, turning on the sacro- iliac joints as on a hinge, begin to separate rapidly, till the time of parturition, when they admit one or tw'o fingers between them. After accouchment, the symphysis quickly returns to its original condition, and in a few days presents only a little thick- ness and mobility, the process being delayed only by age and sickness. Le Gallois found the sacro-iliac symphysis also very moveable, so as to allow of the retreat of the sacrum, and the increase of distance between its ex- tremity and the pubic symphysis when the foetal head pressed upon it. In this manner the pelvis of the Guinea-pig is widened, during labour, in all its diameters. Its young are produced in a very advanced state of de- velopment, and are able to run about and eat as soon as they are born. In the Marsupialia the pelvis is also much developed, both to aftbrd attachment to the powerful muscles of the tail and hinder legs, and, in some of the order, to support the ab- dominal viscera in their sitting posture and leaping movements. It is remarkable for the development, in most of the genera, of two extra bones {fig. 99. «.) characteristic of the order, which are attached to the pubes in the site of the crests and spines of these bones in other animals, and support the abdominal pouch peculiar to them and destined for the reception and more mature development of their young, expelled immature from the [telvic cavity. They are directed obliquely forwards and a little outwarils, in tlie direction of the fibres oftheaponeurosisof the external oblique muscle of the abdomen; in which, according to Owen and Laurent, these bones are de- velojied by ossification of the fibrous tissue. The free extremities are a little curved, and over them the cremaster muscles in the male animals play. The pelves of the Marsupials differ considerably, according as the mode of progression is quadrupedal, or by a succession of springs from the tail and strong hinder ex- tremities. The Wombat may be taken as an example of the former, and the Kangaroo of 160 PELVIS. tlie latter |)clvic type, which approaches in general form to the pelvis of the Jerboa, just considered. The sacrum of the Wombat is very fiat, and strong, and broad, in correspondence with the general squat and massy skeleton of the animal (see Jigs. 102. and 108. Art. Marsu- •pialui). Its curve is a continuation of that of the dorsal and lumbar vertebrae. The number of sacral vertebrae is seven, and the transverse processes are separated from each other, the tliree upper of which are long and strong, and are articulated by their tips to the ilia. The facet on the extremity of the first looks upward and outward, and that on the second, on the contrary, downward ami outward, and form projections which impinge upon the iliac facet. This arrangement in the Wombat like that in the Tapir, is closely ana- logous to the formation of the sacral “joggles,” and the alteration of the inclination of the sacral wedge in Man, at the point of the auri- cular surface opposite the second sacral piece, substituting for ujiward, backwards, and for downward, forwards, a change consequent on the difference between the prone and erect positions. Caudal [)icces are numerous. The Uia are comparatively short and ex- panded considerably, and are curved out- wards in a remarkably strong, broad, hook- like process at the anterior superior spine. They arc placed very obliquely on the spine, being at an angle of 160° with the lumbar portion of the great dorsal curvature. The ischia are thick, long, and massy, and in a right line with the ilia. They have cu- riously bifurcated tuberosities, one tubercular projection turning inward, and the other longer, curving outward, in another remark- able and strong hook-like process, to which formation we have before remarked a tendency in the Hare and other Rodents (fig. 98. c). These processes, like those on the ilia, afford a [jowerful hold and leverage to the strong muscles of the hinder extremities, much used by the animal in its burrowing habits. These hook-like processes of the ischia arc formed by a Y-shaped apophysis analogous to that of the tuberosity in man. The pubes are short and thick ; and the symphysis is parallel to the spine, very long, and joined in very ex- tensively by the vertically directed rami of the ischia. The marsjqnal bones of the Wombatare long, flat, rounded and expanded at their free extre- mities, and articulatevl to the anterior border of the pubes in the position of the crests by two articular facets separated by an arched interval. Ilio-pectineal spines are present, and of large size. The whole pelvis of the Wombat is large ami massy, though the openings and outlets are proportionably very small. It has a flattened appearance antcro-posteriorly, so that the anterior outlet has its greatest diameter trans- versely placed. In the Mprmecobius fasciatus this flattened appearance of the pelvis is still more remark- able. In the Opossums, Perameles, and Pha- langers, there is but one sacral vertebra, which, in the Phalangisla Cookii, is ankylosed to the last lumbar vertebra. The pelvis of the Thplacinus Cpnocephalus approaches closely in many respects to the type of the Carnwora, like many of the peculiarities of this animal. The sacrum pre- sents no angle ; the ilia are massy, somewhat short, and less oblique than those of the Wombat : the ischia are also short and thick, and are placed at an open angle (170°) with the ilia, while the pubes arc short and di- rected almost horizontally inwards, making an anlei'o-poslcrior angle with the ilia as little as 115°. The whole appearance of the pelvis is massy, with small openings. It has neither the oblique a])pearance and exaggerated pro- cesses of the Wombat, nor the elongation and wide outlets of the Kangaroo, while its well- marked ilio-puhic angle contrasts much with both, and shows a strong similarity to the Carnivora. In the Kangaroos, the sacrum is in the line of the lumbar curve, and differs in little but size and breadth from the preceding vertebra;. There are two sacral vertebra;, articulating with the ilia, their transverse processes being long and coalesced, but the s[)inous 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 (hi). The upper part of the iliac wing pi-ojects much on the dorsal aspect of the spinal column, forming with it an angle of 140° (see Jig. 112. 9.). The ischia are very long, broad, and strong, and have much-expanded tuberosities with an outward curvature (Jig. 99. e). These are united in a median symphysis by a single V-shaped epi- physis (c), divided, in the adult, ny a suture from the ischia. The tuberosities support also another epiphysis on each side posteriorly at c, the anterior ischial rami being almost deficient. The ilia and ischia are very nearly in a direct line. Iheptiibes 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-puhic angle is 135°. The marsupial bones (a, 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 (b). The ilio-pectincal spines (d) are very large, for the attachment of powerful psoaj muscles. The direction of the ischio-pubic symphysis 161 PELVIS. (y) in the Kangaroo, Phascognie, and Potoroo, is not parallel with the spinal column, but Fig. 99. Pelvis of ihe Kangaroo, shoiving the marsupial hones (a a) and inter-sciatic epiphysis (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- tebrs posteriorly. The sciatic notch is long and narrow, corresponding to the great length of theischia ; and the foramen obturatorium is large and elongated antero-posteriorly from the same cause. In the Dasyurus and Pc- tawists, 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 j)ro- jection of the caudal spines before mentioned. The pelvic cavity is deep in the Marsujnalia , and its openings are small in proportion to the size of the animal, since the feetus 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. 13ut 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 Petauruts, 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 psoae muscles, and behind by the powerful tail, used as a propelling organ by the sudden action of its flexor muscles. The pelvis of the Alonotremata resembles in general appearance the reptile type, although Sup2r. in some other respects these curious animals, especially the Ornithorhyncus, approach the Birds. The sacrum of the Ornithorhyncus is composed of two vertebrae, separated, as in the Saurian reptiles, and placed in the line of the lumbar curve, differing little in appearance from the lumbar vertebrte. In the Fchidna are three sacral vertebrte, also separated and all uniting with the ilia. The Uia are short, thick, and prismatic, and project above the spine at an angle of 140° as high as the sacral sjunes, 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 jmbes are broad and short, placed at a marked angle with the ilia, I 10° in the Echidna hystri.v and 1‘40° in the Ornitho- rhyncus, and uniting by broad plate-like rami with the ischial rami, which form wdth 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 {^s PC Jig. 177. Art. JMonotremata'). 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 hystriv, the union of these bones is, however, effected by cartilage only, and the acetabula are perforated by a consider- able oiieuing into the pelvic cavity,constitutmg another remarkable reptile-like peculiarity. Having traced the Mammalian pelvis to a form presenting somewhat of the reptile type in the Monotremes, we maj' now recur back to an order of animals which, from thei'- 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 iheSimicc 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- scialic ligaments. We have already noticed an exceptional example of this coalescence in the Kuminants, in the Memitina or pigmy Chevrotain. But the pelvis of the Edentata also presents a diminution of the pubic S3'in- physis, and the absence of the ischia from this junction, a separation which is carried M 1G2 PELVIS. still further in the Inscclivora and Cheiroptera. The increasing ohliqnity of the pubes also indicates an approach to the Bird type. The climl)ing liabits of the Sloths produce a habitual vertical position of the trunk, re- t|uiring for the .support of the abdominal viscera large open pelves. In the Ai (^Bradppus tridaetpliix') the [lelvis {Jig. 100.) is remarkably slender, expaniletl, shallow and horizontal in direction, tlie pelvic openings being very large and roinnl, and tlic antcro-posterior diameters little larger than the transver.se. The ankylosis of the innominate bones to the sacrum in these animals gives a great firmness to the siip[)ort of the otherwise feeble hinder e.\treinitie.s, aiul with the great distance of separation of tlie 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 Tardigradcs. Fig. 100. I'ehis of the Ai, anterior vieic. The sacrum is large, both in length and bi'eadth, very fiat, with lai'ge, open foramina, and presenting a flatteneil surface in place of the posterior spines ami tuberosities. It is composed of five vertebrae, of which the three up|)er (e) as well as the last lumbar (g) are ankylosed to the ilia (6). The union of the last lumbar seems to result from an extension of ossification in the ilio-lumbar ligament (i), and contributes much to increase the steadiness of the spinal column on the|)clvis. The cvcvp.v is triangular, little curved, l)road and sliort, and is composed of six pieces. In some species it is prolonged into a tail. The ilia are short and slender, witli much- expanded wings, having an anterior concavity ami a plane surface [)ostei’iorly. 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 {a), which gives to the angle of tlie bone an ex[ianded appear- ance, and encloses a round, wide sacro-sciatic foramen (d), above and behind the cotyloid cai'it}'. The tuberosities are small, and the inferior rami (/) are long and slender, enclosing witli the pubis a very large obturator foramen, having its long diameter from side to side, ami do not join in .symphysis. The pidocs (A) 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 [iresenting a very slight ilio-pectineal spine (1). Tlie lumho-iliac angle in the adult Bradnpusts about 145°, and the ilio-puhic about 155°, being only about 25° from a right line as in the human pelvis. The ilio-ischkd angle also approaches the human standard in being di- minished to 1.35°. Tills tliminution of the ilio-ischial angle is still more remarkably shown in the Mp- lodoH and jMegatherium fossil gigantic Sloths, whicli approach more closely to Man in this res]iect than any other Mammalian. The osseous system of the fossil Mplodon robnslus closely resembles that of the Sloths, differing from tliem, however, by presenting a continued sacral crest, and more expandeil ilia {Jig. 101.). According to Professor Owen, in his valuable monograpli on the specimen in the Iluntei'ian Museum, the sacrum really con- sists of seven vertebrm, 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 grailually increases in breadth to the sacro-iliac union (c), which is formed by the first, seconil, and third true sacral vertebrfE,and there presents its greatest breadth. It then contracts slightly, and, at the sixth and last, ex- pands again to join the ischia (rf). It is firmly united by ankylosis both to the ilia and ischia. Its anterior surface is curved both laterally and vertically. The spinal canal is very wide, and the foramina passing from it mark the |irimary vertebral divisions. The whole of the eleven spinous processes of the ankylosed vertebrae form a remarkable curved crest pos- teriorly (g). There are twenty*one caudal ver- tebra?, which doubtless, in the living animal, contributed to support the body by applica- tion to the limbs of the trees upon which it climbed, and wei’e strongly supported by the sacro-sciatic ossification. The innominate bones are very large. The iliac wiiig.s are much spread out, widel}' cui- cave anteriorly, and slightly convex posteriori}', tlie.se surfaces being directed forwards and backwards. The iliac crest presents a con- tinuous, well-arched curve, and at the inner |iart of its centre {m) it is prolonged and curved forward in a lip which overhangs the anterior fossa, and contributes to support the bulky viscera. The lips of the cre.st are remarkably s[)read. The posterior superior spine is continued by an oblique crest of bone {a) to the lateral tubercles of the lower sacral vertebra?, as if from ossification of the oblique sacro-iliac ligament. The posterior inferior spines are continued by a ridge to the borders of the fifth, sixth, and seventh sacral pieces into the bony ankylosis of these with the ischia, which are ankylosed to the .same PELVIS 163 parts, evulently in the position of the sacro- sciatic ligaments (d). The ischia (c) are comparatively short and directed obliquely backwards and downwards, and have remark- ably slender tuberosities, as is the general cha- racteristic of the Sloths. The inferior rami (k) slope much forwards, and join with the pubis in a plate of bone {h) before reaching the symphysis (/), which is very narrow and formed by the pubes only. The (i) of the Mylodon are long and very slender, and form an angle of about 160° with the ilia, the apex of the angle being directed forwards, a remarkable peculiarity, by which it differs, in common with the Ant-eaters, from the other Mammalia. The verlehro-illac angle is rather acute, being about 125°, and the ilio-ischial is as small as 120°, being very near the human angle. Fig. 101. 9 Pdvis of the 3fylodon rohustits, posterior view ; show- ing the ossification of the sacro-iliac and sciatic ligaments. The whole pelvis is remarkable for its breadth and shallowness. The anterior outlet is of an oval form, with the long diameters antero-posterior. The posterior o[)ening is somewhat pentagonal, and, from the great antero-posterior direction of the ischial rami and the ossified sacro-sciatic junction, pre- sents a flat level rim. The sacro-sciatic fora- men (1) is comparatively small, but the obtu- rator foramen (o) is large and oval. The pelvis is one of the most characteristic parts of the fossil Megatherium, as forming the fulcrum of muscular forces of unusual vigour. The sacrum is veiy narrow, and shorter proportionably than in the Mylodon, and is composed of five vertebrae, only the last being broader transversely. There is no ankylosis to the last lumbar vertebra. The iliac wmgs are large and expanded, with a concavity directed forwards, the ante- rior superior spines overhanging the femurs, and the e.xternal border very concave. They are more massy than in the Mylodon, and present no hook-like process on the crest. The ischia are broad, blade-like, and massy ; the tuberosities are not well marked, but rounded and ankylosed to the lower sacral vertebrte, enclosing a small foramen, and contributing, with the ankylosed ilia, to sup- port the weight of the animal. Ilio-ischial angle 125°. The pubes are slender and very oblique, and form, like the Mylodon, a reversed ilio-pubic angle of about 155°. The pubic symphysis is narrow', and presents anteriorly a rostrated projection. The acetabula are large and near to each other ; the planes are inclined from the perpendicular about 65°. The anterior outlet is oval, with long diameter antero-posterior. The posterior has the long diameter transverse. The obturator opening is comparatively small. The whole pelvis has a very massive appearance. The pelvis of the other Edentata presents the same general type as that of the Sloths. In the Armadillo {Dasyjms longicaudius) there is a sacrum of nine vertebrte, the three upper of which are ankylosed to the ilia, and the sacral spines are coalesced in a crest. The sacrum is narrowed to a remarkable extent between its iliac and its sciatic portions, ex- panding much in the latter part to meet and coalesce with the ischia, with which it forms a broad osseous plate in the site of the sacro- sciatic ligaments. The oblique sacro-iliac ridge is also w'ell marked- The caudal bones are numerous. The ilia are long, strong, broad, and pris- matic, and the alae are prolonged into broad lamellar plates, w'hich are ankylosed con- tinously to the sacrum, and assist to support the carapace. The ilia are much more ap- proximated to each other than the ischia. Luinbo-iliac angle 155°. The ischia are large, broad, and considerably divergent, with broad tuberosities prolonged dorsally to support the shell ; coalescing in a broad plate w'ith the lower sacral pieces, and enclosing a moderately sized sacro-sciatic foramen. The rami are at right angles to the body of the ischia. The ilio-ischial angle is marked, (14-5°). Tha pubes are slender and very obliquely directed back- wards, making an ilio-pidnc angle of 150°; and the symphysis is short, especially in the Weasel-headed Armadillo, in which also the ilio-j)ubic angle is smaller. (130°). The pos- terior pelvic outlet is much larger than the anterior, from the greater eversion of the ischia. In the Cape Ant-eater (fg. 102.) the sacrum is composed of six pieces, with the spines («) coalesced, but leaving foramina between them, and the last transverse processes (5) elongated. Caudal bones numerous {fig. 102.). The ilia are very thick and prismatic, and more perpendicular to the spine, with the an- terior and posterior borders thickened into a strong ridge. The aim are concave externally, the posterior superior spines (e) prolonged dorsally, and ankylosed to the sacrum, and the anterior superior (g), prolonged and curved outwards and downwards. The ischia are very long, expanding into a broad plate poste- riorly (c), but do not touch the last sacral vertebra. The ischial spines (i) are marked, ami the tuberosities present two tubercular projections, one directed outwards, long and sharp {k) ; and the other thicker, and directed M 2 PELVIS. I6i ilorsally (/). The (rf) are directed obliquely backwards with very short .sym- [)hysis (/), and the ilio- pectineal .spine (/;) is very large. The pelvis is altogether massy ami large, with long sciatic notches and con- siderable obturator foramina. Fig. 102. Pelvis nf the Cape Ant-eater, side vieu’. In the great American Ant-eater, both the ilia and ischia abut close!}' on the saci al trans- verse processes, [)resenting a faint suture at the line of junction. The pelvis is proportion- ately smaller anrl lighter, and the ]iroccsses and spines much less marked than in the Cape Ant- eater. The himho-i/iac rnig/e in the Ant-eatei s is 140°, the ilio-iscliial 140° ; and the i/io-pubic is reversed, and about 1.55°. The Manis possess pelves of the same ge- neral heavy appearance as the American Ant- eater. The ilia ami ischia are closely a[)proxi- mated, but not ankyloserl to the saertim. The symphysis pubis is short and not joined by the ischia, and the pelvic openings comparatively small. In the foregoing Sloths and Fdeniata, and in some of the Rorlents, we have remarked the temlency of the anterior symphysis to become shorter ami more imperfect by the absence of median union of the ischia, and that this is accompanied by a corres[rondiug increase of the bond of unioir between the sacrum and ilio-iscirian elements of the pelvis, by a closer appi'oximation or ossification of their uniting ligaments, to give greater firmness to the pelvis as its anterior connection fails. In the Inscctivora and Bat tribe, this separa- tion of the innominate bones is increaserl, and the pubes also fail altogether, in many in- stances, to meet in the median line. By the classification of animals according to their pelvci devclo[)nient, which is here adopted, these tribes are placeil much lower than their general osteology allows, in the general classi- fication commonly given by authors, ami are allied more closely to the Bird type in their pelvic formation. Of the Inscctivora, the Hedgehog presents the least pelvic de|)arture from the common mammalian type. The sacrum is narrow and triangular, and composed offour vertebras, three of which articulate with the ilia. The ilia ai e thin and elongated, and placed on the spine at an angle of 130°. The ischia are slender, projecting above the level of the sacrum, but not touching it ; and the rami are long and slemler, ami enclose with the pubes large obturator foramina. The pubes are long, slender, and obliquely directed, making an ilio-j)ubic angle of about 150°. The symphysis is very short, and the pelvic outlets large, with the long diameters antero-posterior. In the Tupaia, one vertebra only, out of three, unites with the ilia, and there is a good sized symphysis pubis, as is also seen in the Tenrecs. In the genus Desman tw'o sacral ver- tebrae articulate with the ilia and one with the ischia ; and \.hc pubes are very obliquely placed on the ilia, and, according to Blainville, are placed, anterioi’ly, rather in contiguity than in symphysis, giving to the pelvis very much' of the appearance of that of the Ostrich. In the Macroscelides there is a short and rudi- mentary [)ubic symphysis. The Mole {Talpa) and the Shrews (Sorex) are remarkable foi' a very narrow sacrum, com- posed, according to Blainville, of four ver- tebrae, but, according to Cuvier, of seven in the Mole and three in the Shrews. In the Mole the ilia are solidly ankylosed to nearly the whole length of the sacrum. In the Shrews the two first only of the sacral ])ieces are united with the ilia. The spines in both are coalesced into a prominent sacral crest. Caudal pieces numerous. Tile i//fl arc cylindrical, much approximated, and parallel to the spinal column. The ischia are much elongated, and elevated posteriorly above the sacral vertebrm. The pubes arc very short and slender, and though they unite with the short ischial rami to enclose a small obtu- rator foramen, do not meet in a symphysis, but jiresent an anterior interval, said to be wider in the female than the male, and causing the whole pelvis to assume very much a bird-like appearance. The pelvic cavity and outlets are so strait that the sexual and urinary organs and rectum pass altogether in front of it. In the Bats (CheiroiAera) the sacrum (fg. 103, e), is very narrow, compressed posteriorly into a straight continuous bone, with no lateral foramina, and composed of three to four ver- tebr;e, which are joined by ankylosis to three or four upper coccygeal vertebrae, or to more in the tailed species. 'I'here are six to twelve caudal bones, sometimes absent, as in Pterupus and Vampire. Fig. 103. Pelvis of the Tcrnafe Bat {natural size'), anterior view ; showing the inter-puhic separation {d, d'). The ilia (a,) are narrow and subcylindricai, with a thick anterior spine, placed parallel to the vertebral column, and anhylosed to the anterior sacral vertebrae. The ischia (c) are in the same right line with the ilia, and are PEL^■IS. 165 ankylosecl at the tuberosities with the last sacral vertebrae, and, as seen especially in the Ternate Bat, given in the above figure, pre- senting an appearance as if ankylosed to each other in one mass, from the extreme narrow- ness of the sacrum at that part, inclosing a small sacro-sciatic foramen. The pubes (b) are thick, short, and very oblique, joining with the short ischial rami at d, to form an elon- gated obturator foramen (/). The ilio-pectineal spine (/^) is very prominent, and recurved almost like a marsupial bone. This is especially seen in the Vespert'dio spectrum, in which it is considered by Wagner as the first indication of a marsupial bone. The pubic symphysis is totally wanting generally in the Bat tribe, leaving a large interval (d, d') ; but, accord- ing to Pallas and Schreger, the males of some species possess a symphysis, which is wanting in the female, a peculiarity curiously illustra- tive of the influence of sex on the pelvis. In a specimen in the Hunterian IMuseum the symphysis, or a close approximation of the bones, is certainly present, though veiy short. The cotyloid cavities in the bats are closely approximated, and are directed backwards as well as outwards, causing the retroversion of the feet seen in these animals. The pelvic cavity and outlets are much more capacious than in the Mole and Shrew. \n t\\e Cetacea, which are in other respects osteologically allied to the Pachydermata, the pelvic development suddenly becomes dege- nerated into small elongated bones, which may be considered as the homologue of the pubes, and which are imbedded in the muscles of the abdomen immediately in front of the ventral opening, and give attachment to the crura penis. They differ, only in being thicker and less transparent, from the pelvic bones of the true Fishes, between which and the INIammalia these animals are the connecting link, as the Bats to the Birds, and the Mo- notremata to the Chelonian reptiles. In the Dolphins these pubic bones are two simple, elongated, flat bones placed on each side of the median line. In some Whales they are connected by a cross piece, and assume a hyoid shape {^see fig. 257. Art. Cetacea). In the Dugong it is a V-shaped bone formed of four pieces, and articulated to one of the ver- tebrae by its free extremities. In the Manutus, according to Cams, they are entirely wanting. The pelvic structure of Birds is charac- terised by very evident distinctions from the mammalian type, the osseous parts being ac- cumulated, as it were, on the posterior and lateral parts, leaving the anterior parietes deficient, and being also thinner and more spread out, so as to leave smaller foramina. The sacrum {fig. 101. a) is generally broad and large, consisting of from eight to twenty pieces, being increased forwards by ankylosis to the vertebrte corresponding to the lumbar region of the Mammalia, and which contribute to support the iliac wings. This arrangement, as well as the extensive ankylosis of the ilia and ischia, has an evident relation to their bipedal support, and is compensatory for the deficiency of the pelvic circle anteriorly. It is much more extensive in the Ciirsores and those which use the legs as the most usual instruments of progression. The bodies of the sacral vertebras are raised in a continuous ridge on the anterior aspect, those imme- diately between the acetabula being larger and broader than the rest {fig. 105. a). The first five or six {s), which may be considered as the ankylosed lumbar vertebrtE, present marked spinous processes united in a high crest which intervenes between, coalesces with, and sup- ports the iliac wings at their inner margins {fig. lOI. b). Their transverse processes, which are also ankylosed to the ilia near their outer borders, are strong and well marked on the ventral sui fiice, and differ from those of the true sacral vertebrae in being more pro- minently advanced and having a direction more horizontally outwards instead of back- wards and upwards {fig. 105. r). the most pos- terior being the thickest and placed at the junction of the iliac wing with the shaft. A Fig. lOI. Superior or dorsal aspect o f the pelvis of the Duck : a, sacivun ; b, coalesced lumbar spines ; c, sacral suture ; d,‘_ ilium ; e, cotvlo-sacra! rib ; f, ischio-sacral buttress; g, sacro-iliac plate; h, sacro- sciatic plate; i, acetabulum; /;, ischium; I, sacro- sciatic foramen ; m, rudiments of ischial ramus ; n, spine; o, anterior obturator., foramen ; />, pubis; cj, ilio-pectineal spine ; r, anterior ischio-pubic union. little anterior to the acetabula, however, where the true sacral vertebrae may be con- sidered to commence, the spines graduallv become less marked as they emerge fi'om between the iliac wings and form a more or less flattened surface («), which is separated M 3 IGG PELVIS. from the coalesced transverse processes by two faiTitl^’-markcd longitudinal grooves. The transverse processes of the true sacral ver- tebra: present a very prominent framework of ridges anteriorly 105.), which have a direction upwartls aiul backwards as well as outwards, the most strongly marked being op])Osite the acetabula (A). They are coalesced on the superior asjiect, by a tliin plate of bone only. The sacrum, as seen from above {Jig. lOI.), has a diamond-shaped a[)- pearance, and is marked out from the iliac and ischial elements by a faintly-marketl suture (c). The sacrum in Birds is a continuation of the line of the great dorsal curvature. The coccyx is generally short, composed of from five to nine jiieces, generally perforated for the spinal marrow, and curved dorsally, as w'e have observed before in some Rodents, terminating in a spinous-shaped piece {see Jig. 107., a). The ilia are comparatively short and narrow : with a very short cotylo-sacral rib or shaft (c), directed upwards and forwards, and expanding into a wing {d), concave or grooved supe- riorly. The (da is (irolonged forwards on the posterior surfaces of the ankylosed lumbar vertebrae, coalescing with their spines and transverse processes; and also extends back- wards to a less degree, to coalesce with the upper bifurcation of the anterior extremity of the ischium, in a sort of lndlress{f),vi\'\\c\\ jirojects externally and overhangs the aceta- luduin posteriorly, presenting, below, a facet, against which rests the trochanter of the femur, and which is apparently a continuation of the articular cotyloid surface. This but- tress is continued from the ischium inwards, as a strong riiige, to the extremity of the strongest of the sacral transverse processes before mentioned {fg. 105. i), ojiposite the Fig. 105. Inferior or ventral view of the pelvis of the Par- tridqe — natural size: o, coalesced bodies of sacral vertebroe ; h, saci'al transverse processes ; n, ischial spine ; r, lumbar or pseudo-sacral processes ; s, anky- loseil lumbar vertebra:. The remaining letters refer to the same parts as in fig. 99. lateral angles of the diamond-shaped sacral plate, and evidently contributes in tlie greatest degree to support the trunk upon the femurs in the standing posture. The principal part of the ilium in birds is composed of the alse, w hich lie almost altogether on the dorsal aspect of the spinal column. The total axis of the ilium, however, crosses that of the spine at an angle of from 150° to 160°, and does not, strictly speaking, lie parallel to it, as is com- moidy asserted {see Jig. 112. 10.). From tlie posterior part of the inner border of the iliac wing passes backward a thin pfo/c oj bone {g), along the external borders of the diamond-shaped sacral plate, from which it is marked by a distinct line of suture (c). It is continuous, posteriorly and externally, vvith the sacro-sciatic ossification, to be presently men- tioned, from which it is also marked, especially in the Partridge and some other birds, by a raised line of demarcation {i). This thin plate is convex above and concave below, and enters into the formation of the pelvic cavity, being much hollowed in the Partridge and the Gal- linncecB generally {Jig. 105. g), to receive the pelvic viscera. It seems to result from the ossification of the sacro-iliac oblique ligament, and to form a separate pelvic element which may be called the sacro-iliac, or ilto-sacral. The ischia of birds (/r) are long, strong, and divergent posteriorly ; and, from the perfora- tion of the cotyloids, appear to be bifurcated at the anterior extremity. The inferior bifur- cation is horizontal, coalesces with the ilium and {)ubis, and separates the acetabulum (i) from the obturator foramen (o). The su|>erior bifurcation is vertical in direction, separating the acetabulum {/) from the sacro- sciatieforamen (/), and coalescing above, inter- nally with the long sacral transverse process {b) and ilio-sacral bone {g), and anteriorly w'ith the ilium in the ischio- sacral buttress (/), !)efore mentioned, which it principally con- tributes to support and form, and which maybe considered as tiie homologuc of the ischio-sacral arch in the human pelvis, separated from the cotylo-sacral rib {e) by a thin plate of bone above, and by the perforated acetabulum below. The posterior extremity of the ischium is much elongated, and constitutes the bulk of the bone. Its inferior border is spread out into a broad thin plate, slightly prolonged into an anterior process {m), which seems to represent the ascending ramus of Mammals, from its frequently uniting with the pubis and forming the posterior boundary of an obturator foramen. Its superior border is prolonged into a broad thin plate (/:) hollowed out in the pelvic cavity, and which constitutes the sacro-sciatic pelvic element, being evidently formed by ossi- fication of the sacro-sciatic ligaments, from .'ts completing posteriorly the sacro-sciatic foramen (/), and coalescing with the sacro-iliac plate (g), before mentioned, and, behind it, with the sacrum. The posterior extremity of the ischium is prolonged generally into a tlnn angular spinous process (w). The ischia m Birtls generally form a right line with the ilia; but in the Birds of pi'ty they constitute a remarkable exception, and make a very PELVIS. 1G7 marked ilio-iscliial angle in the reverse direc- tion to that of Mammals generally, i. e. with the retiring sides anterior {see jig. 107.). The imhes of birds are generally long, .slender, rib-like, and divergent, and are com- posed of a single curved branch {jj, having no angle, and never forming a true interpubic symphysis, though, in the Ostrich and Falco Fulvus, they are closely approximated at their posterior extremity, and form a sort of sym- physis. The ilio-imbic angle is very large, from 155° to 160°, except in the birds of prey above alluded to ; and the pubes and ischia are generally almost parallel. Sometimes the posterior extremities of the pubes and ischia unite to form complete elongated obturator foramina ; and they may be united also near their anterior extremities, forming a lesser an- terior division of the foramina, as in the Cur- sores {see jig. 106. hj Very often, the boun- daries of the obturator openings are incom- plete from the failure of this junction, and the ibramina are wanting altogether ; or the an- terior union and foramina only may be present, as in the Duck {jig. 104. r), from deficiency of the pubes posteriorly, or their entire approxi- mation to the ischia. The pelvic cavity is in- creased in size posteriori}', by the divergence of the pubes and ischia, and is capable of great enlargement by the yielding of their unfixed extremities. The ilio-pectineal emi- nence is generally present, and often large in size, constituting a spinous process {([). The acetahula (i) are perforated and placed almost close to the borders of the sacrum, and generally much anterior to the centre of the whole pelvic length, that the points of support may be nearer the centre of gravity. The bird’s pelvis thus constitutes a firm, compact, immobile, box-like structure, de- ficient inferiorly, affording a large and firm hold, by the elongated and strong ischia, for the extensor muscles of the leg ; and, by the large sacrum and ankylosed ilia, for those of the trunk, which is placed almost entirely in front of the supporting femora, and always more or less at an angle with them, except in the Grebes and Penguins. The centre of gravity is not, in birds, directly above these supports, as in the true erect position of man, but is placed considerably in advance of the femurs, and necessitates considerable flexion of the lower parts of the legs, and great length of toes, to keep the centre of gravity within the base of support. The long pelvic muscles, the tendons of which reach to the toes, by a constant tendency to flex them, contribute mainly to preserve this semi-erect position, even during sleep, and independently of the will of the animal. The pelvis of the Cursorcs {fg. 106.) ap- proaches most neaily in the massiveness of the bones to the Mammalian type, as well as, in the Ostrich, in the formation of a pubic symphysis. The sacrum {a) is very long and narrow, and is composeil, according to Cuvier’s tables, of twenty pieces in the Ostrich and of nineteen in the Emu and Australian Casso- wary. The spinous and transverse processes are distinct, and coalesced only at their ex- Fig. 106. Dorsal vieio of the pelvis of the Ostrich : a, coa- lesced sacral spines; 6, ilium; c, c', sacro-iliac i)late ; d, sacral chink ; e, ischium ; f, ischio-sacral buttress ; g, pubis; h, symphysis; i, acetabulum ; k, anterior ischio-pubic suture; /, anterior obturator opening; !«, ilio-pectineal spine ; o, posterior or greater ob- turator hole. tremities (a), in the Ostrich (the former being the only part of the sacrum appearing dorsally), presenting another close ap[.roximation to the Mammalian condition. The ccicc^.v is straight, and composed of seven pieces, which are perforated for the termination of tlie spinal marrow, and end in a conical bone. In the Rhea or American Ostrich, boih the .sacral ami coccygeal bones are much atrophied. The ilia {b) are comparatively very short, especially in the Rhea. Tlie aim are thick, short, and little curved, and lie close to each other at the u|iper half of their inner borders, by which they are ankylosed to the sacral spines, whose coalesced extremities are seen between them, forming a tent-like eminence above the anterior sacral vertebras and sup- ported by their spinous processes in the manner of tent poles. Anteriorly, they overla[) the posterior ribs ; and posteriorly, they are prolonged on the sides of the sacrum into a distinct and prominent dio-sacral element. This is an elongated piece of bone, with a superior (c) and a lateral {c') surface, nr 4 IG8 PELVIS. tapering gradually to the posterior extremity of the sacrum, where it terminates in an outward curve ; and placed upon the transverse processes, which it encases, like a frame, on each side, aiul to which it is firmly anky- losed by its inner surface. In the Ostrich, its thick upper surface or border does not unite with the similai- bone of tlie opposite side, nor with tlie sacral crest; but is separated from it by a chink, or oval opening, d, gradually narrowing posteriorly, in which the sacral spines (ff) are seen distinct and separate, and coalesced only at their extremities. 0|)posite the three last sacral spines, however, the ilio-sacral pieces are ankylosed to the sacral ridge, and terminate posteriorly the oval chink. In the Emu and Rhea, the ilio-sacral pieces are coalesced in their whole length with the extremities of the sacral spines, and a narrow diamond-shaped dorsal plate is formed, composed almost entirely of the united ilio- sacral plates, and having its angles at the massy ischio-sacral buttresses. The hchin (e) are very long and thick, and form, l)y the superior vertical bifurcation of the cotyloid extremity, a very strong isc/do- sacral Imflrcss (/), coalescing at that point w'ith the ilium, sacrum, and ilio-sacral plate. In the Ostrich and Emu the ischia are not connected [tosteriorly with the sacrum, but a wide and elongated sacro-scialic notch inter- venes. In the latter, the ischial extremities are free and tubercular. In the Rhea they are ankylosed, by their posterior four-fifths, not only to the sacrum, but, like the ischia of the Bats, to each other, passing in front of the coccyx anti greater part of the sacrum, thus excliuling tliem from the pelvic cavity, and enclosing complete sacro-sciatic foi'amina, which open into a sort of [tosterior pelvic cavity. The yjaici' (g) are long and slender, and are unitetl posteriorly to the ischia in the Ostrich and Rhea, completing the Obturator Foramina ; but, in the Cassowary, the [tubes, as well as the ischia, are free at their posterior extremities, and the obturator foramina are incomplete, like the sacro-sciatic. In the Rhea and Cassowary they are witlcly diverging ; but in the ostrich they a[)proacK each other in a wide curve [losteriorly, and unite in a median iiiterpubic symphysis (h), which curves forward anteriorly in a hook-like process, and completes an oblong anterior pelvic outlet with its longest diameter antero-posterior. The iUo-pid)ic angle is 140° in the Rhea, and 155° in the Ostricli and Cassowary. The ilio- [lectineal spines are well marketl, especially in the Ostrich (m). The acetabula (i) are per- forated, and open partly into the pelvic cavity, and [)artly upon the sacrum, and are so closely a|)proximated that the bodies of the vertebrae only intervene. Immediately below the ace- tabula, the ischia and pubes are connected, on each sitle, by the suture of an ischial apophysis with the pubes (A), across the obturator mem- brane, enclosing a smaller obturator opening (/), which transmits the vessels and nerves, and intervenes between the larger obturator opening (o) and the acetabulum. In the Apteryx the ilia are longer and more concave su[)eriorly,.antl the ilio-sacral prolon- gation short ; and both are separated more distinctly from the opposite ones by the coalesced extremities of the sacral spines, forming an elongated ridge of bone down the middle, and sejtarated from the ilia and ilio- sacral pieces by distinct parallel sutures. The ischia, in this bird, as well as in the fossil gigantic iJhionu',?, or wingless bird of New Holland, are not [)laced, as in the Cursores before mentioned, parallel with the ilia, but form an anteriorly retiring or reversed ilio- ischial angle of 140° ; and they do not coalesce posteriorly, either with the pubes or the sacrum, but have free truncated extremities, presenting a great general resemblance to the [)elvis of the Emu. The are parallel to the ischia, and, like them, free and diver- gent. In the Natatores the pelvis is long and broad, and generally much expanded posteriorly by' the divergence of the ischia and large sacro- sciatic ossification, for the attachment of the powerful muscles used in swimming ; and the great intercotyloid distance gives to their gait its peculiar waildle {see Jig. 104.). That of the Loons aiul Penguins, however, is remark- ably contracted, long, and narrow, with little intercotyloid distance. The usual number of sacral vertebrae is fourteen, as in the Swan; the Grebe has thirteen, and the Duck fifteen, and the sea Swallow ten only. The sacrum is usually very broad ; but in the Penguin and Loon it is unusually narrow, and in the former it is united by ankylosis to the last dorsal vertebra. The coccyx is usually composed of eight pieces. The Goose and Pelican have but seven, and the Barnacle Goose nine. In Penguins it is strong, and assists in the support of the body in its usual vertical position. It is usually curved much dorsally, affording a larger pos- terior pelvic outlet. The ilia are moderately long, and overlap the posterior ribs. In the Penguin they are said, by Wagner, not to be ankylosed to the sacrum, but connected only by ligamentous union ; thus increasing its loose and waddling gait. The uchia are very long, divergent, and largely expanded into a very broad sacro- sciatic element, enclosing a small sacro-sciatic foramen. They are prolonged posteriorly into a sort of styliforni process in the Auk and Puffin. The pubes are very long, slender, and divergent, and are expanded at the extremity, and curved inwards in the Swan, Diver, and Gannett. They do not generally unite with the ischia posteriorly ; but, in the Swan, Duck, anil Pelican, the obturator foramina are com- [deted by the union of these bones, and are small and elongated. The GaUinece have large and strong pelves, in correspondence with their powerful legs, used chiefly for progression and scratching up their food. The sacrum is broad, and composed of from ten pieces, as in the Tui’key, to fifteen in the Pheasant and common Fowl. The PELVIS. coccy.v has five pieces in the Pheasant and Turkey, and,’ in tlie latter, is said not to be perforated for the spinal chord. In the Pea- cock there are eiglit pieces, and the terminal bone is a horizontal oval plate to support the radiating feathers. In the tailless Manx va- riety of the common Fowl, the coccyx is aborted into a single tubercular projection." The i!ia and ilio-sacral ossifications are broad, and the ischia long, divergent, and widely expanded posteriorly into a very broad sacro- sciatic element, much hollowed out in the pelvic cavity, and enclosing a large foramen (see fig. 103./). This is especially marked in the Crown Pigeon, Bustard, Crested Curassow, and Guan. The pubes are long, and generally unite with the ischia to complete an elongated obturator hole (p). In the Dove, the pubes and ischia are united in their whole length, and the foramen is obliterated, while in the Crested Guan and Trumpeter it is subdivided into an anterior and posterior portion, as in the Ostrich and Rhea. In the Grallatores the sacrum is broad, and composed of from ten to twelve pieces, but in the Oyster Catcher there are fifteen. In the Snipe the transverse processes are more or less separated. The coccyx is in seven or eight pieces. The Uia and ischia are shorter and broader than in the Natatores, the former being placed more parallel to the spine, crossing it at about 165° ; and the latter forming an ilio- ischial angle of 160°. The inter-cotyloid dis- tance is very great, especially in the gigantic Crane, but in the Stork and Bittern the whole pelvis is smaller and more contracted. The pubes are long, diverging, and parallel to the ischia, especially strong in the Aptenodytes ; and enclosing often a large obturator foramen by coalescing with the ischia. In the Stork, Ibis, and Flamingo, however, there is no such union. In the Scansores, the sacrum of the Parrot is short and very broad, the ilia and ischia also short and broad, as well as the ilio- sacral and sacro-sciatic bones, inclosing a small foramen ; and the pubes, uniting with the ischia in two distinct places, encloses a subdivided obturator foramen. The coccyx of the Tou- can is long and very flexible. In the Passeres, the sacrum is composed of from ten to thirteen pieces ; but in the King- fisher there is but eight. The coccyx is in seven to nine pieces, very flexible in the Pies and Swallow; and in the Woodpecker very strong, and supporting on its anterior aspect, near the extremity, a remarkable, round, concave disc, formed by the coalescence and spreading of several of the bones anteriorly. Its use is evidently to support the body by being ap- plied to the stems of the trees to which it clings in the pursuit of its prey and attaching the spreading tail feathers. The ilia, ischia, and pubes are slender in the Passeres, and the obturator foramina generally incom- plete. The pelvis of the Raptores, or Birds of prey (fig. 107.), is narrower, the bones more corn- 169 pact and massy, and less expanded than in the foregoing orders. The sacrum is narrow, and composed gene- rally of eleven bones, which, in the Spat row- hawk, are ankylosed to the last lumbar ver- tebra. The coccyx is straight, and in seven or eight pieces, with a large and blade-like ter- minal bone directed dorsally («). The ilia (b) are proportionally larger, and project more dorsally than in the other orders, overlapping the spine with elongated wings, concave externally; and a strong tapering ?7io- sacral plate (g), w'hich is directed much down- wards, as well as backwards, to unite with the sacro-sciatic plate (rey. In some Falcons and Vultures, how- ever, according to Cams, they are united in their whole extent ; while, in the Owls, this union does not take [)lace at all. The Reptile pelves present some specimens which approach the Mammalian t3[)e, in the formation of a perfect [)elvic girdle by inter- pubic and inter-ischial symphysis. In these animals, however, the three conqionents of the innominate bones remain separate through- out life, and are connected in the acetabula by ligament only. The manner of articula- tion of the ilia with the sacrum is also cha- racteristic. We have seen that in Mammals this connection of the ilia takes place about the centre or at the anterior half; and in Birds by the whole length of the alas. In lleptiles it takes place by the tip only of the upper extremity of the ilia, giving much less strength, but far greater mobility to these bones. In the Chelonian and Saurian reptiles also, the ilia are directed forwards and down- wards instead o( backwards and downwards, as in Birds and Mammals, and thus the axis of the anterior pelvic outlet is directed upwards and forwards, and the lumbar vertebrre, instead of the coccygeal, form part of the posterior pelvic w'all. The pelvic bones are simple, aiul the sacro-sciatic notch can hardly be said to exist. In the Ophidians and some Saurians the pelvis, like the corresponding extremities, is totally wanting. In theChelonia, — the fresh-water, and the mnd Tortoise, or Trionyx, have a sacrum composed of three pieces, soldered, like the dorsal ver- tebrre, to the back-plate. Their long transverse processes project from it, and unite in a tuber- cle at their apices, to which the ilia are attached. The caudal vertebree are numerous. The ilia (Jig. 108. «.) are short, thick, curved roundish and clubbed inferiorly, and are di- rected outwards, forwards, and downwards, extending under the back jdate directly be- tween the sacrum (at i) and the acetabula. In the Tortoise and Trionj x 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, backw'ards and inwards, and unite in a median .symphysis (d), forming the real pelvic circle, and present- ing a sharp angle posterioily 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 openiTig, and the pubes and ischia have the appearance of large ribs connected at their ventral extremities. The pubes (b) are the Tig. 108. 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, uhic angle is about 160°, retiring posteriorly in the Great Monitor Lizard, and the ilio-iscliial angle is very acute, being 60° only (see fig. 112. 13,). In the Menepomaalteghani the sacral trans- verse processes are directed backwards, and support apophyses to which the ilia are at- * Lecture at the Koj-al Institution. tached. The pubes and ischia are short and oblong, and so approximated as to leave no obturator opening. Upon the pubic spine, in the Cameleon, are two cartilages, which have been stated by Duges to be of a marsujiial character. A Fig. 1 1 0. A, pelvis of the Great 3Ionitor Lizard. K, ilium, ischio-puhis, and marsupial cartilage of the Salamander (after IJuges), seen from below, and twice the natural size. From the pelvis of the fossil Ptcrodaclyle Cuvier concludes that the forward direction of the ilia, the anterior position and pointed extremity of the pubis, and the separation of the pubic and ischiatic symphysis, ally this animal to the Saurian reptiles. In the tailed Batracliia and Ichtkycic rep- tiles there is but one sacral vertebra supporting rib-like transverse apophyses which connects them to the ilia. The ilia are long and slender, and the pubes and ischia are blended together in one large, squarish, cartilaginous plate, not perforated, and loosel}' connected by ligament with the one of the opposite side. In the Proteus the ilia are small, and the w'hole pelvis very little ossified. In the Salamander, also, the ilia are small (see fig. 1 10. B, a). A cartilage, of a Y shape (d), is placed at the anterior margin of the ischio-pubic plate (h), which Duges looked upon as marsupial, but which Meckel has considered as part of the sternal elements, and which is a bifurcated pro- longation of the cartilaginous ischio-pubic sym- physis (c). There is also a very small obtu- rator opening in the ischio-pubic plate (h). The ossification of the pelvic bones in these animals, according to Duges, takes place in the same order as in man. The pelvis o( theAxolotl is, like that of the Salamander, not quite ossi- fied. In the Siren, according to Cuviei', there is no vestige of a pelvis. In the Ophisaurus, CeEcilice, and Amphisbcenn, there are onl}' rudi- raentarv vestiges of the ilia and ischia ; and in the apodal Saurians, as in the Ophidia, a single bone only is found, under the skin near the anus. In Pscudopus anguis and Acontia are simple elongated pelvic bones, articulated by ligament to the last dorsal transverse processes. In Eryx boa a pair of elongated bones lie parallel to the rectum, free from the spinal column. They are sometimes found in several distinct pieces. In the Sauroid reptiles the acctabida are di- rected horizontally' outwards, and the inflex- ions of the feet are made perpendicularly to the rachis or plane of motion, the thigh being 172 PELVIS. ilirectecl outwards, the knee always bent, and tlie body trailing. They walk on the fore and hinder legs alternately, and leap by a sudden flexion of the body. The pelvis of the Anourous Batmchia is interesting from the changes which affect it, in their transition from the ichthycic to the (juatlni[)eilal condition. The sacrum of the Frog {Jig. 1 11. A and n) is considered by Duges to be formed by the last dorsal vertebra, which closely re- sembles the preceding ones, except in having very long and strong transverse processes (e), to the tips of which the ilia are moveably arti- cnlatctl. In the liana pipa and Toad, how- ever, the sacrum presents evident indications of a division into two vertebrai, there being on each side a foramen for nerves, with two prismatic and very rough transverse pro- cesses. The coccyx of the Frog is composed of two [iieces {/), which, in the adult state, are ankyloseil together and to the sacrum, and consiilered by some to form part of that bone. They are formed, respectively, from three |)oints of ossification. In addition to these there is a long cylindrical terminal spinous or btyloid process (g), which is formed by a single separate ossific point, and becomes ankylosed so the other p.irt at the adult period. This is tonsidered by some to be a second sacrum, cud by others a coccyx. It has been supposed ay Duges to cause, by its progressive ossific development, the mortification and dropping off' of the tail at the period of transition from the tadpole condition, and thus closing up the spinal canal posteriorly. Fig. in. Trout. The (/^) are very long and cylindrical, and directed backwards,becoming almost horizontal in the liana -pipa. They suspend between them, by their ajiices, the long transverse processes and body of the sacrum, like the springs of a coach. At their opposite extremities tney are ankylosed, not only with the ischiaand pubes, but tinih each other (Ji) ; and thus the acetabula, of which they form the greatest portion, are closely ap[iroximated, and the pelvic outlet assumes a V shape with the base at the sacrum and the angle at the coalesced ex- tremities of the ilia. The and ischia of both sides are coalesced together in an azygos osseous plate (c), with a central rounded crest marking the position of the symphysis (r/), the pubes being the last to ossify. There is no foramen obturatorium. The iJosterior outlet of the Frog’s pelvis looks almost directly upwards, and the anus opens, at the extrenjity of the coccygeal spine, upon the dorsal aspect of the animal. In the immature Batrachian a triangular- shaped cartilage intervenes between the op- [)osing ilia and the other pelvic bones in the acetabula, which afterwards becomes oblite- rated by the ankylosis of the bones. Duges calls it an “ os paracotyleah” analogous to the “ [taraglenal” bone of the shoulder of the same animal. There are also epiphysial pieces on the ilia and ischia which represent the crest and tuberosity of those bones respectively. The soliility ami firmness of union of the ischio-pubic portion of the pelvis in the frog is a remarkable instance of modification and adaptation ofform to meet the requirements for a strong and firm hold for the powerful triceps cruris, external obturator, hamstring, and ^ad- ductor muscles in the thigh of this animal. The single pair of glutei also obtain an ex- tensive attachment from the long ilia, and the pyrifurmes from the long coccygeal spine, while the strong abdominal muscles, acting on the moveable ilia, give, as it were, an additional segment to the hinder extremities. In this manner the fiog’s [telvis is strikingly and di- rectly adapted to its leaping progression. In the Fishes the pelvic structures dwindle to elementary [jieces, such as we have men- tioned in the bimanal and apodal Reptiles, and finally disappear altogether. The pelvis is represented in these animals by two bones, sometimes coalesced into an azygos bone, which supitort the ventral fins. In the Pisces thoracici these are suspended by ligament to the coracoids, by whicli they are advanced anterior to the [tectoral fins, and connected to the head ; but in the Pisces abdominales they are detached from the coracoids, and are suspended in the muscles at the posterior part of the ab- domen. They are, however, subject to great diversity of position. Owen considers the pelvic bones of fishes to be the homologues of the pubes ; but, in the opinion of Cams, they are to be considered as iha. Their inferior and ventral position, their occasional union in a symphysis, their frequent coalescence, and their attachment to the generative organs, however, would support rather the conclusion of Professor Owen; the support of the bones of the extremities not being exclusively the iliac attribute, but also PELVIS. 173 usually contri'.'utecl to by tlie pubes and ischia. In Fishes, a supporting arch from the spinal column to the posterior limbs * is not wanted, but rather a free and unimpeded motion for the caudal extremity, used in propelling the body. In the Angler there are two pelvic bones, each consisting of a vertical portion, which, in this instance, seems to represent the iliim, and a horizontal one, w hich meets in a symphysis with the one on the opposite siile, and is the homologue of the pubis, the pectoral rays being attached to the angle of union of the two portions. In the Rays and Sharks, w'here the pelvic extremities are better de- veloped than in other fishes, the pelvic bones consist of one piece, placed transversely, resembling that which supports the pectoral fins, and suspended loosely, like it, by a ligament to the spine. In the Sharks and Chimera; are found, articulated to it, by means of an intermediate cartilage, two club-shaped bones, called claspers, which are used to em- brace the female in the generative act. In the Torpedo, and also in the Cyclobates oligo- dactplus, an extinct Ray, the pubic bone sends forward two processes, somewhat resembling marsupial bones. In the Sturgeon, the ptlvic bones are almost entirely separated from each other, and consist of small triangular pieces, with their apices directed forw-ards, and sup- porting the cartilaginous fin rats. In the Cod-fish there are two sub-triangular bifur- cated bones, connected to each other by liga- ment, and suspended from the coracoids, the rays of the ventral fins springing directly from them. In the Trout, the pelvic bones are also two in number, flat and of an elongated tri- angular shape, with the base directed pos- teriorly, and supporting the ventral fins (see Jig. 111. c). In the Haddock, there is a single bone, presenting a central oval opening with the shorter diameter transverse. In the Cyprinus, Scomber, and Zeus, they present backward spinous projections. In the Rhombus and Loricarta there is seen an ankylosis of the anterior caudal vertebra, forming a sort of sacrum, and presenting the first indication of the formation of this bone in the animal kingdom. Subjoined is a table, showing the compara- tive pelvic angles in Man and the principal genera of Mammalia, Birds, and Reptiles. The measurements were princi|)ally taken, with great care to insure correctness, from the specimens in the Hunterian Museum, through the kindness of Professor Owen. The rela- tive size or total disap|)earance of the verte- bro-iliac, sacro-vertebral, and the ilio-pubic and iUo-ischied angles in the different tribes, w'ill be here seen at one view. It may be observed that the two former may vary some- what through inaccuracies in articulating the skeleton, or with the variations of the ver- tebral curve, and that the results here given are to be taken in this particular, as approxi- mative only. But the ilio-pubic and ischial angles cannot, from the ossific union of the bones, be subject to such accidental variations. The accompanying diagram is intended to show the absolute lines of direction or axes of the pelvic bones and spine seen in profile, with the angles above referred to, in the prin- cipal pelvic types. Fig. 112. Lines of direction and profile angles of the pelvic hones. 1. Human type ; fac, V'ertebro-iliac angle ; fag, sacro-vertebral angle; acd, ilio-ischial angle ; acb, ilio-pubic line, forming an anji/e in all other animals. 2. Orang type. 3. Monkey type, no ilio-isebial angle. 4. Edentata tj-pe, ilio-pubic angle reversed. 5. Carnivora type, ilio-ischial angle reversed. 6. Pachyderm type. 7. lluminant type. 8. Rodent type, no ilio-ischial angle. 9. Kangaroo type. 10. Bird type, ?;o ilio-ischial angle. 11. Raptores t3'pe, ilio- ischial angle rencrsecl. 12. Clielonian type. 13 Saurian type, ilio- pubic angle reversed, and remarkably acute ilio-ischial angle. PELVIS. 17I Table of Comparative Pelvic Angles. 5 . f .2 Jl II £ ' “• .52 1. Man bcRreei. Degrees. Degrc'e.s. Deg. - 155 0 no 117 ‘i. Orang - 160 125 165 150 3. Cliiinpanzee - - 155 120 do. 160 4. Gibbon . - do. 130 0 170 5. Baboon (brown) - do. 110 0 155 (160 90) ti> 120 ) 6. Monkeys- - \ 0 0 ( 170 7. Lemur (albifrons) - 170 120 0 0 8. I. oris gracilis - - do. 75 0 0 9. Sloth (Ai) . 145 155 135 0 10. Mylodon (fossil) - 125 155 120 160 f’i'verscd 11. Megatherium (ditto) — do. 125 — rei/rj'scd 12. Armadillo _ 155 150 145 0 13. Ant-eaters - 140 155 do. 0 revi’rsi'd 14. Lion - 150 120 0 170 15. Tiger . 160 no 165 do. reversed 16. Leopard - - 1.50 120 0 do. 17. Hyicna - - 140 125 0 160 18. Bear (brown) - - do. do. 0 do. 19. Badger - do. 130 0 no 20. Hacoon - - ISO IkS 160 0 21. Elephant- - 120 100 145 170 22. Hliinoccros - 125 150 do. do. 23. Hippopotamus - 160 125 170 160 V4. Hog - 145 120 do. do. 25. Tapir - 125 145 140 0 26. Horse _ 130 130 145 0 ( } 27. Ox tribe - - 130 130 ISO (150) 28. Deer tribe . 1.50 140 150 160 29. Irish deer (fossil) 145 135 do. do. 30. Girafle - 1.50 140 145 170 31. Camel _ 140 120 155 1.55 32. Sheep and goats 145 130 150 170 33. Rats and mice 170 150 0 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) ISO 115 do. 0 •39. Ornithoriiyncus 140 120 155 0 40. Echidna (hystrix) do. 110 0 0 41. Hedgehog 130 150 0 0 42. Bat (Ternate) - 0 100 0 0 ( 150 ■ ( 160 155) 43, Birds, generally - to ■ 160) 0 0 44. Ostrich - 160 1 55 0 0 4.5. Rhea ating 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 ischio-pubic coales- cence is seen in the Batrachians and the saltatory Carnivora, Ruminants, and Marsu- pials ; its entire absence in some of the Che- lonian 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 vertebrae in quadrupeds characterised chiefly by saltatory quadrupedal progression, and requiring long iiokl for the great muscles of the hip, as the Carnivora, the Deer ti'ibe, the Monkeys, the Horse, and the Frog, — while it is contracted to a remark- able degree in the Walrus and Seal, which apjiroach in their habits the Cetaceans and F'ishes, in w hom the iliac element of the pelvis is the first to disappear altogether. Its alee we see elongated behind the sacrum in those animals whose pseudo-sedentary habits retiuire a long leverage for the muscles of the back arising from the iliac crest, such as some of the Rodentia and the Kangaroos — and its alee, on the contrary, to be expanded in those requiring support to the abdominal viscera, either from their size, as in the Pachydertnata, 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, ami 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 onlp, destined to the truly erect posture; — and in those animals formetl 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 ot the way of tlie approximated femurs, in their semi-flexed and angular movements on the pelvis; — hut 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, probabi}', to a ta|iering extremity and fish-like outline. The iliac crest and its j^osteiior spines and hibcrositp are the hypertro|)hied, coalesced, and s|)read-ont tubercles of the sacral ribs, a bomologue which will be made more evident by the consideration of the homologues of the j)elvic ligaments. The epipleural spines of Fishes, and the costal ap|)endages of Birds, show the serial homology of these processes. The Y-sluqied cpipltpsial cuh/loid bone of M Scrres has been considered by some to represent a marsupial bone ; but, seeing that in the marsupials themselves these Y-shaped bones anti 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 acetabtduin fsee fig. 110. Art. Marsii- pialla) ; and one of a similar nature and position is de.seribed by Geoffrey St. Hilaire as present in the acetabula 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 complementarj ossific points which are seen in the opposed articular surfaces of the bodies of the true vertebrm, ami also in the sacral ver- tehrm, and in the articular ends of some long bones, — as those forming the elbow-joint. From the piosition of the ilio-pcclincal emi- ncnce 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 [)roccss 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 of develop- ment with the marsu|)ial bone, the opinion that it I’epresents that bone, seems to be quite untenable. We have seen it most de- veloped in those animals whose posture or structure re(|uires largely-developed jjsoec parvcE muscles, as in the Marsupials arul 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 w'ould 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 sjnncs of \.he 2>ubes in Man and some animals ; and it would ajipear, 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 e.vternal j^illar of the ring, or PoujjarCs ligament, and which is implanted upon the pubic spine.* In support of this opinion, it may be stated that, in I’ou- part’s ligament near the s|)ine of the pubis, cornicles, similar to those in the stylo-hyoid ligament, are said to have been found in the luiman subject. The cartilages upon the ])ubic [)late 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 Dnges as having a marsupial character. The epiphysial jilatcs, forming the articular surfaces of the pubic symphysis in man, are analogous with those which form the auri- eulnr 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 atlult Kangaroo, we have seen that a single V-sha[)ed epi[)hysis is jdaced 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 7%. 99. c). These epiphyses appear to result from ossification, by independent centres, of the inter-pubic and inter-ischial fibi’o-car- tilages, and to constitute, in these animals, a serial homology with the central ossific jjoints of the sternum and xiphoid appendix ; and they may be consitlered as I’epresented in the human subject by the inter-pubic Jibro- cartilages, which are continued along the ab- dominal walls to their sternal homologues by the linca alba ; as the pubic and ischial ele- ments themselves are represented bythe/mc<2 Iransvcrsce, and their cotj loid junction by the external border of the ajyoneurosis of the ex- ternal oblique muscle and the linea semilunaris. The two cartilaginous plates of the pubic sym- physis would seem to be the homological re- jiresentatives of the double lateral ossific j^oints, often found permanently separated by an open- ing in the lower pieces of the human sternum, and in the bifurcated xi|)hoid appendage. We have seen tltat, while in the Kangaroos and the leapitig Rodents, Ruminants, and Carnivora, the ischial and pmhic symphyses are largely developed and coalesced, and seem, in many cases, to be compensatory for the weak- ness of the sacral portion of the pelvis; in the Sloths and some others the ischial symphysis is entirely wanting; and in the Bats, Shrews, Moles, and Birds, the elements of the pubic symphysis also entirely fail. A congenital and similar deficiency of this .symphysis has been observed in some human pelvic mal- formations, from arrest of development. This deficiency may be well compared to a like congenital absence of the sternum, some in- stances of which have been recorded. The loss of pelvic firmness consequent upon this is compensated for, in great part, in the animals just named, by the ossification of another pelvic element, the sacro-sciaiic. * Laurent anil Qcven consider theso bones as sesamoid trochlear ossicles. (See Art, Marsu- pinlia.) PELVIS. 177 These are represented in Man and Mam- malia generally by the sacro-sciatic ligaments, and appear to be ossified by extension from the epiphysis of the ischiadic tuberosity, and from the ischiadic spine. In Birds, they constitute an important element of the pelvis, and are separated, more or less, from the ischium and sacrum by a faintly marked suture, more evident, however, at the sacral extremity. Taken in a scientific point of view they represent two additional pelvic rib shafts, or •pleurajtophyses, of the two last sacral vertebrae, and are implanted on the sacrum, in the human pelvis, in the site of the two lower lateral epiphysial plates of that bone, exactly as the ilia are articulated upon the three upper. Their extension to the coccyx would also seem to connect them with the elements of the first coccygeal vertebrae ; — and their attachment to the ischia would be, in this point of view, a repetition of the kind of union of the latter bones with the descending pubic rami, as the cartilages of the false ribs are connected consecutively to each other iu the thorax. The obturator and sacro-sciatic foramina, considered in this light, constitute simply consecutive and enlarged inicrchondral and intercostal spaces respectively ; the lesser sa- cro-sciatic foramen becoming, in the Sloths, Bats, and Birds, entirely obliterated. This manner of viewing them explains the ap- parently indifferent wmy in which the boun- daries of these openings, especially the ob- turator, are left incompleted, or entirely obliterated, in Birds and Reptiles. The cotyloid notch may be thus considered as the commencement of the obturator separation, and the formation of two obturator open- ings, as in the Ostrich, may be readily ex- plained. The obturator membrane may also be thus related to the anteiior intercostal aponeuroses, and the membranous expansion of the upper border of the great sciatic ligaments (before mentioned as connected with the fasciae cover- ing the internal obturator and pyriformes mus- cles), to the posterior intercostal ligaments. The homologues of the ligaments of the sacro-iliac articulations are readily found in those connecting the head, neck, and tubercles of the thoracic ribs to the vertebrm. The a?tterior and superior sacro-iliac ligaments are evidently repetitions of the anterior or stel- late costo-vertebral ; the superficial fibres of the posterior sacro-iliac, repetitions of the posterior costo-transverse ; the deep fibres, or inter- osseous sacro-iliac, of the middle or interosseous costo-transverse ; and the ilio-lumbar and lumbo- sacral ligaments, of the oblique or an'erior costo- transverse ligaments of the ribs. The connec- tion of the last-named ligament with the trans- verse process of the vertebra above, and with the iliac crest below, is very similar to the oblique direction and attachments of the homologous costo-transverse. The ossifica- ;ion of these ligaments in Sloths, Bats, and ^specially in Birds, gives additional support to heir otherwise feebly connected pelves. The ligaments of the pubic symphysis find Slip]]. easily their homologues in the chondro-sternaf ligaments. The anterior and posterior peripheral inter-pubic ligaments are repetitions of the similarly placed and constituted chondro- sternal, which, like them, connect the hasma- pophyses together across the interposed elements, as well as directly to the endo- sternal bones and inter-pubic fibro-cartilage. The superior pubic ligament finds its homo- logue in the inter- clavicular, and the sub-pubic, in the chondro-xiphoid and interchondral fibres. It would be easy also to point out the mus- cular homologues of the two regions; but space will not permit more than to mention the evident ones of the external and internal oblique muscles with the similarly placed and directed intercostals ; of the levator ani with the diaphragm ; and of the pyriformes with the psocB muscles. The internal obturator imiscles would represent the triangtdaris sterni and transversalis abdominis; and the exter?ial, the lesser pectoral and external oblique muscles. The homologues of the pelvic bones with those of the shoulder are best seen in the Rep- tiles. According to Duges, the pelvis of the Salamander has a close resemblance to the shoulder of the Cameleon. The ilium is generally considered to be the homologue of the scapula ; the pubis, of the clavicle ; and the ischium, of the coracoid bone. Meckel considers the body of the ischium to represent the spine of the scapula; while, in the opinion of Oken, the jmbis represents the acromion pirocess, ani.1 the marsupial bones the clavicles. In the shoulder of the Cameleon, the sca- pula is longer even than the ilium, and the furcular clavicles and coracoids are ankylosed together like the ischium and pubis. And, in the pelvis of the Crocodile, we have seen that the ischium excludes the pubis from the formation of the acetabulum by an apophysis which overhangs that cavity, somewhat as the human coracoid process intervenes between the glenoid cavity and the clavicle. The ascending branch of the ischium may, further, be taken to represent the ejticoracoid bones of the Monotremes, Lizards, Batrachians, and some Fishes, as the Cod, Carp, and Perch, In the Cock-fish, Snipe-fish, and Lancet-fish, these bones are joined in a kind of symphysis, forming an independent arch behind the sca- pular arch. And those bones of the scapular arch oi the Fish, which are considered by Owen to be the coracoids, (but by Meckel, Agassiz, Geof- froy, and Spix to be clavicles,) unite also in a median symphysis, presenting an homologous affinity to the ischial symphysis seen in the Reptiles, — the whole of these symphysial ele- ments being represented, combined, by the elongated ischio-qmbic symphysis in many Mammalians, but especially in that of the Marsupials and Monotremes. {John Wood.) Bibliography. — Descriptive Anatomy, bv Quain, Cruvelhier, and Meckd. Ward, on the Bones. Ellis's Demonstrations. John James Watts, Ana- tomico- Chirurgical View of the Male and Female Pelvis. Encyclopedie Anatomique — Joiudan’s N 178 PELVIS. Translation ; — Osteologie and Syndesmologie, par M. Scemvitrring; Jlechanique des Organes de la Lo- comotion, par G. and/d. //Tier, vol. ii. — Dev^eloppe- nient de I’llomme et des Mainmiferes, par Dischnff', vol. viii. Bordlo, de I\Iotu Animalium. Welter, IF. and E., Mechanik der iMenschlichen Gehwerk- zeuge, Gottingen, IbSli. Memoirs de ITiistitiite, tom. vi., 180G. — Tcjinii, Memoir sur Ics Os du ISassin de la Femme, p. 14i). Saudiforf, De I’eh'e ejus in partu dilatatione. Xacc/ele, Des principaux Vices ;7io»n:A' to those of the ‘‘ standard” pelvis ; and, — Irregularities from ini'perfeet de- velopment, in which the shape deviates from, and the diameters are not in proportion to, those of the “ standard.” Equable deviat'ions. — “ Pelvis equabiliter justo major.” — The irregularity in this pelvis con- sists in all the diameters being in e.vcess. It is not uncommon. Burns records one ex- ample. Dr. Murphy has another in his pos- session, and there is in the Museum of King’s College a third, the brim of which measures G inches transversely, by 5 inches antero- posteriorly. The largest hitherto recorded is one by Giles de la Tonrnette, who gives in. The distance between iliac crests - - 12-|^ „ Antero-po.sterior diam. of - 6^ „ Transverse diam. of do. - 6j- Both the diameters of inferior outlet - The disadvantages of this pelvis are said to be prolapse and displacement of the viscera, sudtlen expulsion of the foetus, inversion of the uterus, and want of the [iroper impress of rotation on the head. Retroversion of the uterus and its prolapse in the impregnated state, are said by some to be most commonly ob- served in hirge pelves. “ Pelvis equabiliter justo minor. ” — In this pelvis, all the diameters are pro|)ortion- ately diminished. The diminution is said, by Churchill, to be generally about one-fourth. Naegele thinks it to be more common than had been supposed by Bandelocque and other writers on midwifery. Veljtean gives two cases of “ Etroitesse ahsolue ” {Journal Com- plementaire'), in which the diminution was so great that one woman died undelivered, and the other underwent the Ccesarian operation. It was considered by Alexandei' Shaw *, that proportionable contraction of the pelvic di- ameters is very common in rickety subjects, from want of proper osseous development, and that it is generally accompanied by correspond- ing diminution of the size of the bones of the lower extremities. The experience of Rokitan- sky also favours the opinion that this propor- tionate contraction, without distortion of the pelvis, may be produced by rickets. Naegele, however, records three female pelves affected with this deformity, which presented no ap- [learance whatever of rickety change, neither in strength, weight, nor texture, one being even heavier than usual ; nor were there any rickety symptoms in their history'. Two of the subjects died after severe instrumental labour ; ami the third, after one miscarriage, died undelivered of the second conception, from ru|)ture of the uterus; comparison «ith the child’s head afterwards showing, that de- livery of a liv'ing child would have been im- possible without the Cmsarian section. The diameters were generally above an inch less than the standard measurement. The ages of these subjects were from twenty-three to thirty-two years, showing that the contraction ' was an adult deformity. They were also ' about or above the average height. Women ' of low stature, indeed, have most commonly large pelves as well as large heads, and are i not more liable to this defoi mity than those ‘ * Mecl. Clhrurg. Transactions, vol. xvii. PELVIS. 179 of taller stature ; the height of the individual being dependent, chiefly, upon the length of the lower extremity and spinal column, which in these cases are disproportionate. The pelvis of the true dwarf, however, in common with, and in proportion to, the osseous system generally, is contracted and stunted in growth. In the Museum of the Edinburgh In- firmary, is the skeleton of a male adult ilwarf, in which the pelvic pieces and epiphyses are not united by bone, but there is no distortion. Tlie jaws are infantile. The pelvic bones in the well- known skeleton of the female dwarf in the Hunterian Museum are in a similar incom- plete condition. Sudden and universal “ar- rest of development^ is apparently the cause of this curious immature condition. In Naegele’s collection is the pelvis of a female dwarf, aged thirty-one years, whose height was 3 feet flinches, the measurements of which are given as a specimen of a distinct kind oi“ pelvis equahiliterjusto minor” by that eminent author in the Appendix to his valu- able work — “ Das schr'dg verengte Becken,” as follow — - . 2 7 conjugate diam. - 3 0 transverse do. - 3 7 antero-postr. do. - 3 3.1 transverse do. - 3 0 transverse diam. - 3 0 Between the sacral promont. and tip of coccyx - - - - 3 3 Between the sciatic tuberosity and iliac crest - - - - 5 5 Between sciatic tuberosity and linea innom. Cavity Length of pubic symphysis - - 0 1 1 The pelvis was perfectly regular and nor- mal in symmetry and proportion, presenting all the appearances, in these respects, of the adult “standard.” The sub-pubic arch, the sacral curves, the direction of the ischia and the curvature of the pectineal line were per- fectly regular. The sacral bones, however, and the three pieces of the innominate bones, were united by cartilage only, ossification not having taken place. In this respect only is this pelvis allied to the class of deformities re- sulting from imperfect development, or to an im- mature pelvis. These peculiarities may possibly be explained by supposing the “ arrest of de- veloqjment,” which dwarfed the woman, to have taken place after the age of puberty, anti the development of the sexual organs, but before the union of the sacral and innominate pieces, that is, between the fourteenth and sixteenth years. This supposition is moreover strength- ened by the fact, that the ischio-pubic rami were firmly united, that the woman had men- struated at the proper period, and that all the limbs were in normal proportion to the body. Neither in the history of the case, nor in the appearance of the skeleton, was there any sign of rickets. The woman had become pregnant, and by the advice of the medical attendants, premature labour was in- duced at the sixth month, and the patient was safely delivered by the forceps, but died ten * Khineland. days afterwards from the consequences of in- discretion in diet. Out of the three cases of pelvis equabiliter jiisto minor given by Pi'ofessor Busch *, and quoted by Dr. Bigby, there was a fatal termi- nation in two instances. In one case, the pelvic diameters were universally half an inch below the standard size. In another, which resembled that of a child, they were contracted in every direction three quarters of an inch. The last ought, probably, to come under the denomination of an inlantile pelvis. In the above cases, the contraction of the pelvic diameters is marked and absolute ; but there is a considerable class of cases, included among the variations of measurement of normal pelves, in which the diameters are diminished in a much less degree, and yet their relative ). The lower lumbar vertebrte and sacral promontory are twisted considerably towarils the left side, and dragged backwartls, the sacral promontory being also considerably raised up- wards (c). The pelvis is of exceedingly large general capacity, and otherwise well formed, showing evidently, by the preponderance of the conjugate diameter and appearance of the sacrum, the effect of the deformed spine upon it. The conjugate diameter of the brim measures as much as 5 and a half inches ; the transverse 5i inches. At the outlet, the distance between the tuberosities is only 31- inches, and the sub-pubic angle 75° ; but, from an unfortunate deficiency of the lower end of the sacrum, the antero-posterior diameter cannot be measured. In the same Museum there is a young male adult skeleton in which this form of pelvis is also well shown. It, also, is coexistent with, and dependant on, a backward cur- vature and shortening of the spine, and ex- tensive ankylosis of the vertebrae in the dorsal and lumbar regions. The lumbar ver- tebrae are inclined much backward, so as to drag in the same direction upon the upper end of the sacrum ; while the upper dorsal vertebra; incline forward, so as to bring the 1st dorsal over the centre of the pelvic circle. There is, in this case, no lateral deviation of the spinal column. The tibiae and fibulae have an inward curve, indicating the existence of a softened rickety state of the bones at an early period of life. In the Hunterian collection of pathological specimens is a young adult pelvis, nutnbered 3-l-“20, presenting the same kind of deformity, accompanying the same kind of backward angular curvature and ankylosis of the bodies of the vertebrae at the same |)lace — viz. the junction of the last dorsal and 1st lumbar. The 1st dorsal vertebra, in this skeleton, likewise occupies a [losition above the centre of the pelvic opening. The u|)per end of the sacrum is dragged backwards by the inclined lumbar vertebrae so as to increase the con- jugate diameter of the brim to 4^ inches. The lower end of the sacrum is tilted forward so as to bring the tip of the coccyx to within a short distance of the ischial spines. The cotylo-sacral arch is stretched out, and the transverse diameter of the brim reduced to 4 inches only. The acetabula are directed more downwards than usual, and the right iliac wing is pressed outwards by the 9th and 10th ribs, which rest on it, and the venter completely flattened out. I find that Rokitansky has met with in- stances of this oblong deformity of the pelvis, coexisting with backward angularity of the spine. In cases of backward angular curvature low tiown the spine, especially where there is no lateral deviation, there will be a tendency to production of this form of pelvis, especially if the bones be somewhat softened, as they usually are in these cases; and al- though such cases of pelvic distortion are, as far as 1 have seen, more common in the male, yet the same cause occasionally produces this effect upon the female pelvis, and may produce obstruction during parturition, not only by the contraction of the antero-posterior diameter at the outlet, but even at the brim, by the diminution of its transverse diameter. An acute angle in the lower part of the sacral curve may also produce this contraction of the inferior pelvic outlet. When this exists singly, the elevation of the coccyx is more considerable than usual, and the axis of the in- ferior plane directed more backwards. This bending upwards of the apex of the sacrum is, however, most usually seen in connection with more general pelvic deformity, and is some- times accompanied by ankylosis of the sacro- coccygeal joint. In a case recorded by Mr. Bell, the antero- posterior diameter of the inferior outlet was contracted to half-an-inch only, and in one of Naegele’s, it was even less than this, in both entirely precluding delivery. In so great a contraction, the sacral bend must have been unusually great, or the lower end of that bone tilted forward in the manner just de- scribed. PELVIS. 185 Distortions affecting the whole pelvis. — In these cases the pubic hones are always more or less extensively implicateJ in the distortion, and entering, as they do, into the formation of both brim, cavity, and outlet, all these parts of the pelvis are contracted or mispropor- tioned. At the brim, however, the obstruc- tion usually takes place, while the operations necessary to procure delivery through the natural passages are rendered more difficult by the distortion of the cavity and inferior opening. General distortions of the pelvis are com- monly divided into three kinds, named, from the shape of the brim, the ovate or elliptical, — the cordiform or angular, — and the obliquely ovate. The ovate, elliptical, or reniforni p>elvis. — In this distortion the sacrum is placed almost horizontally, so that the sacral pro- jects forward to a great degree, generally at the same time deviating from the median line, and considerably sunk in a direction forwards and downwards, so that the lowest lumbar vertebra forms the most projecting point. The lateral sacral curve is diminished, flat- tened out, and often bent backwards on each side the promontory. The vertical curvature is generally diminished and flattened in some degree, and directed more downwards by the more horizontal position of the bone; but occasionally there is an acute bend forwards at the lower part. The coccyx is generally bent acutely forwards. The ilia and ischia on each side are often removed to a greater lateral distance than normal. The iliac wings are flattened and directed more forward ; and the cotylo- sacral arch is more sharply curved, and often shorter and thicker than normal. The planes of the ischia diverge instead of slightly con- verging downward ; the spines anil tuberosities being likewise divergent, and the latter di- rected more outwards and backwards. The superior rami of the pubes are generally flat- tened out, having little anterior projection ; while the inferior rami are widely divergent, affording a wider and shallower expansion of the sub-pubic arch. In some cases, however, the sub-pubic arch is little altered. In some instances the symphysis of the pubis presents the appearance of being in- dented or pushed backwards, giving an out- line to the brim of an hour-glass shape. The diameter principally diminished is the conjugate of the brim, and often one or other of the oblique diameters. In one variety the transverse diameter of the brim is also con- tracted. The transverse diameter is, however, sometimes undiminished, or even increased. The transverse diameter of the inferior outlet is generally most considerably increased ; but the antero-posterior diameter is most usually con- tracted by the bend in the sacrum. In many instances, however, it is considerably enlarged. The depth of the true pelvis is generally dimi- nished, and its capacity lessened. The sacro-vertebral angle is generally much diminished, from the backward horizontal di- rection of the upper end of the sacrum. The inclination of the superior plane is some- times increased so much as to be vertical ; the axis of the brim being generally directed more forward than in the “ standard," and that of the inferior outlet more backward. Some- times, however, they are very little altered. The structure of the bones is light, slender, and fragile, indicating the origin of the dis- tortion in rickety softening. Examqiles of this kind of pelvis are nu- merous. One of the most well-known is that of Elizabeth Sherwood, who was delivered by Dr. Osborne by means of the crochet. The measurements of this pelvis are given as fol- lows:— From the most prominent point of the lumbar vertebra to the upper border of the pubic symphysis, li inch. From the same point on the left side to the left pectineal eminence, If inches. The same measurement on the right side. If inches. From the sacral promontory to the pubic symphysis. If inch. Transverse diameter of brim, 5 inches. Left oblique ditto, 4f inches. Right oblique, 4f inches. Antero-posterior of cavity, 2f inches. Tran.sverse ditto, 5 inches. Antero-posterior of outlet, inches. Transverse, 4f inches. Sub-pubic angle, 100°. The measurements of a very extreme case of this kind of distortion are recoriled by Dr. Ramsbotham (see fig. 117.) as follows: — Fig. 117. Ovate pelvis. {After Ramsbotham.') Conjugate or sacro-pubic diameter of brim, J of an inch onl}'- From right side of sacral promontory to right pubis. If inch. The same measurement on the left side, if inch. Antero-posterior diameter of outlet, 2 inches. Transverse diameter, 4f inches. The shape of the brim in this pelvis is hour-glass, the pubic symphysis being pushed back. Such a pelvis, in the opinion of the above-named writer, would necessitate the abdominal section. In a less extreme case, given by the same writer, the sacral promontory and lumbar curve bend much more considerably towards the left side. At the brim, the conjugate dia- meter is ]f inch; the right sacro-pubic, 2 186 PELVIS. inches; tlie left, -J of an inch only. The transverse tlianieter, measured in the lateral curve of the brim, GJ inches. At the inferior outlet, the antero-posterior, drl inches ; the transverse, 5i. In the figure of this pelvis given by the author, the long axis of the sacrum is represented as jdaced obliquely across the median line, its apex inclining to the right side; while the tuberosity of the right ischium is widely ilivergent, principally causing tlie increase of tlie transverse tlia- meter of the outlet. The left ischial tube- rosity and acetabulum are brought more tinder the line of gravity. The left superior pubic ramus is thus pushed nearer to the promontory than the right, causing a slight twist in the pubic sympliysis. In this pelvis the author considers that delivery might be efi'ected “ per vias naturales,” by craniotomy. In one of Dr. llull’s cases, that of Ann Lee, affected with this deformity, the con- jugate diameter was reduced to If inch, and the sacro-cotyloid on each side equal, and measuring 1^^ inch. The transverse diameter, in its widest part, amounted to inches only. There was little flattening of the pubes, the contraction being produced chiefly by the projection of the sacrum, the chief bend being near the sacro-iliac joints. The distance between the antero-superior iliac spines was only inches, but the dimen- sions of the cavity and inferior outlet were not materially diminished. In Mr. Thomson’s case of Cmsarian section, the pelvis was affected with this deformity. The normal lumbar curvature was so much increased, together with the pelvic inclination, that the sacrum was placed qiute horizontal, and the superior jtlaue directly vertical, and its axis consequently parallel with the hori- zon; but with little or no lateral deviation of the sacral promontory. The legs were crooked, and the acetabula faced directly forwards. The conjugate diameter ol' the brim was diminished to f of an inch ; the transverse was about 5 inches, and the inter- sciatic ap]tarently about If.* I)i'. Robert Lee gives the dimensions of a case of ovate delbrmity in wdiich the patient, after being deliveretl by craniotomy at an early jieriod of jtregnancy in the first labour, died in the second from rupture of the uterus. The conjugate diameter of the brim was 2 inches 1 line; the transverse, inches. At the outlet the distance between the sciatic tuberosities was 4i inches; between the tip of the coccyx and lower border of the jtubic symphysis, Sf inches. This obstetrician con- siders that if, in this case, premature labour had been imluced at or before the filth, in- stead of the seventh month, the patient might have been saved. j" It has been said that in pelves presenting the ovate deformity from rickets, the contrac- tions of the diameters of the brim are generally * ]\Ied. Observations and Inquiry, vol. iv., with plates. t Lectures in Med. Gazette, 1843, p. 181. accompanied by the enlargement of those of the outlet, and the numerous examples of enlarged transverse diameters of the outlet, in particular, are adduced. In an ovately deformed pelvisin the Museum of King’s College, liowever, in which the con- jugate diameter of the brim is 2 inches, and the ti-ansversc also contracted to inches ; at the outlet the inter-sciatic diameter is contrncied to as little as 3^ inches, and with it the sub- pubic angle is iliminished also, while the antero-posterior is increased to 41: inches. This pelvis is remarkable for the great flat- tening of the sacrum, the anterior surl'ace of which lies almost in a straight line, in which direction the coccyx also is nearly placed. The antero-posterior diameter of the cavity is thus reducetl to 3-1 inches. The distance between the ischiai spines is, however, 4 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 Ity 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 li inch, while the direct measurement is reduced to |i 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 thii-d, it is diminished to 4| inches. In many of these cases we may conclude that the cotylo-sacral rib was shortened as well ns bent backward. The transverse diameter of the inferior opening is not enlarged in all the above-mentioned cases. In one it amounted oidy to 3-|, and the suh-pubic angle (mainly depending on this diameter) is only 70°. Tlie antero-posterior diameter is, in' three cases, increased to from 4 to 4| inches, while in the remaining two cases it is diminished to 24 and 2|-. These latter measurements, doubtless, de|iend 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, wiiich is often found in these [lelves, is produced mainly by the shortening of the cotylo-sacral rib of the ilium in the line of,-- pressure, without any eversion of the lower • part of the innominate bones. A singular [lelvic deformity, related in some degree to this class, is represented in Moreau’s plates, in which, by an anterior PELVIS. 187 bend at tlie lower lumbar vertebras, tlie sacrum is placed horizontally backward, and the sacro-vertebral angle diminished to rather less than a right angle. The eifect 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 e.xception 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 angidar pelvia. — This distortion presents wide differences to the kind just described. The sacral promontory, though in some measure projecting forwards, yet is more decidedly 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 hollmu 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 acetahula 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-iliac 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 tuberosity, 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 wdiich 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, generall}' 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 [)oint the sides of the arch bulge outwards. In the rostrated pelvis, it is often completely obliterated or transformed into a mere chink. The acetahula are elevated and turned more forwards than normal, and in many examples of rostrated pelvis are directeil almost quite anteriorly. The angles of both the superior ami inferior pelvic planes with the vertebral column are lessened. In a case given by Xaegele, thesupe- 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 forwarti, 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. \ 18.), upon whom hysterotomy was per- formed by Dr. Hull in 179-1, 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 If inch in diameter would not pass through it at any part. At the brim, the 4-th 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 inches. The distance between tlie superior pubic rami at Fig. 118. tlie ])oint of angular bend, was of an inch. From the 4th lumliar veitebra at its upiier anterior border, to the left acetabulum, was only f of an inch ; on the right side The greatest transverse diameter was of inches. At the outlet, tlie distance between the sciatic tuberosities was inches ; between the spines 2|. The greatest contraction of sub- pubic arch was at the sciatic rami, which were only of an inch distant from each other; above this, the arch bellied out. Tbe sacrum was bent double, so that the tip of the coccyx was only l^V’'ich 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 Ctesarian sec- tion by Mr. Barlow, are given as follows : — From the fibrocartilage between the 4th and 5th lumlxir vertebrae (which is sunk down so as to occupy the normal position of the sacral promonton), 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 tbe same point, to the right acetabulum f of an inch ; to the left acetabulum If inch. Tbe greatest available space is, from the left side of the sacral promontory to the left ilium, and amounts to If inch. The greatest lateral space, following the curve, is 5f inches. At the outlet, the distance between the sciatic tuberosities is If inch. The coccyx and lower part of the sacrum are bent upwards, so as to bring the tip of the coccyx to within If inch of the sacral pro- montory, and to 2f inches from the point of contact of the ascemling 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 CtEsarian 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, 2f in- ches ; both the oblique, 3f inches. Cavity: — antero-posterior diameter, 3f inches ; trans- verse diameter, 2f inches. Outlet: — antero- posterior diameter, 3f inches ; transverse diameter, 2^ 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 tbe Ijrim is diminished by the projection of the sacral promontory, and the bend in the pubis, to If inch. The same measurement on the left siile of the promontory, 2|- inches ; on the right side, 2f inches. The longest transverse diameter is 4f 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 syni[)bysis measures 44 inches. In the opinion of this author, a foetus might be extracted from this pelvis by craniotomy. In Dr. Cooper's case of Ctesarian section, the pelvis was affected with the angular de- formity to the extent of reducing|the conjugate diameter of the brim to If inch.; and the trans- verse diameter of the otUlet to 4 an inch only.* In Dr. Kellie’s unsuccessful case of Ca;sarian operation, the pelvis was of the 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 tbe pelvic brim. The right lumbo-cotyloid diameter was only of an inch ; the left, Iffj. Between the lumbar vertebra, and the bend of the pubic rami, was only of an inch. At the outlet, the intersciatic distance was only 24(j ; antero-posterior, 3,% 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 14 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 tbe other case, the conjugate diameter was reduced to J 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 previou.sly' ; the last case four years before the ojteration.-f- Dr. Hamilton’s case was also rostrated, the * Med. Observ. and Inq. vol. v. p. 218. •j- Edinburgh Med. and Surg. Journal, vol. h'. PELVIS. 189 piibic rami being approximated at the angular bend to f of an inch. In a case wiiicli was operated on by Dr. Hfebeke, and described in U Experience (No. 140.), the inferior pelvic outlet was nearly closed up entirely, the ischial tube- rosities being approximated to within two lines only, 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. Churchdl {fig. 119.). In this pelvis the snpe/ior ptuhic ramus Fig. 119. 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 “ mollities ossium" or “ malacos- teo7i." 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 pubertj^ according to some authors. It is characterised * Lancet, 1840. t Metl. Chir. Trans, vol. vii. p. 264. 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 liy, 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‘G0 Carbonate of lime - - 2'66 Soluble salts . - . 0'62 Total of inorganic matter - 18 '88 Cartilage, vessels and fat - 81 T2 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. When 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 190 PELVIS. of the weight of the bone) in 100 pnrts — the great diminution of the eartliy nuitter will be evitlent. In rickets the bones of the lower extremities first exhibit deformity, which apjiears chiefly as an aggravation of the natural curves under ])ressure, ami as a yielding in the direction of the lines of muscular motion. The femurs, for instance, are bent, in most cases, with the con- vexity forwards and a little outwards ; the tibiae and fibulae generally with the convexity foi'wards and inwards, so that the knees are bent inwards and the feet thrown outwards and backwards (see 122. li and e.) The bones of the pelvis and spine become affected, and those of the upper extremities, ribs, and head afterwards follow. The s[)inal column may be extensively deformed, especially at its upper part, with- out any deformity whatever of the pelvis. An exani|)le of this is to be found in the Museum of King’s College, and many in the Hunterian Museum. Many others are also recorded. In most of these cases, however, the special curvature residts from caries of the vertebra;, or lateral curvature. Meckel remarks, that spinal curves result- ing from general disease of the bones, such as rickets, are usually accompanied by pel- vic deformity. The lumbar [tortion of the s[)ine is curved forwards and sideways, the thoracic portion backwards ; and sometimes, the bodies of the vertebra; become affected with caries, and produce angular curvature and ankylosis. The sacrum at the same time sinks under the weight of the spine, and the pelvis becomes iin()ressed, generally, with the complete ovale diUortion, or one of the partial deformities of brim, cavity, or outlet, which arc its commencements. In a good many cases, however, as we shall presently see, the rickety pelvis assumes the angular form of di.stortion ; and, in some, the oblong form jtreviously described. It is, however, univer- sally shallow, contracted, and of small ca- pacity. The iliac wings are thin, and pre.sent a greater central area of translucency than usual ; while the columnar masses of bone are shorter, lighter, and less dense, but often [>resent, as we have seen in the ovale jielvis with universally diminished diameters, a thickening of their bulk, corresponding to the shortening they have experienced by pressure. llokitansky mentions that this thickening takes place in common with all the osseous structures aboundinsr in diploetic tissue. In many instances, it evidently depends upon the excess of reparative osseous deposit, described by Stanley as taking place in the lines of the greatest [tressure. In all the siiecimens I have examineil, it takes place by far the most considerably in the cotylo-sacral rib, through which the greatest amount of pelvic pressure passes. Shaw pointed out that in most rickety deformed pelves, the contraction of the diame- ter at the brim is universal as well as dispro- portionate, from the absolute shortening and atrophy of the bones. In fourteen rickety fcmal adult [)elves, he found a general de- ficiency, in the measurements of the bones, of one quarter of the whole normal size. He also found that the bones of the lower ex- tremity generally are atrophied in this disease more than those of the u[)per.* Rokitansky also considers rickets to interfere with the general development of the bone. AloUities ossium or A'la/acosteon adidtorum is a disease, not very frequent, affecting the full-grown adult skeleton. It most commonly affects the female sex about the middle period of life, but seldom, according to Rigby, attacks women who have had no children. Three instances in which this disease occurred in the male subject are, however, given by Mr. Curling in the Med. Chir. Trans, (vol. xx. p. 360.). Nor does it seem to be confined to middle age — in Kellies’ case, the woman was aged only twenty-seven years — nor to par- turient women, as will be seen in Mr. Solly’s case. In many cases, it is said to depend upon the cancerous diathesis, and to result from the dissemination of cancerous matter throughout the system, infecting the nutrition of the animal matter of the bones, and replacing the earthy constituents ; thus causing the osseous structures to lose their cohesive power. By far the greater proportion of the complete cases of pelvic deformity, as well as the most extreme and universal contraction of diame- ters, have resulted from this disease. For the particular pathological instances of this remarkable disease the reader is referred again to the article on the Pathology of Bone (|i. 44-2. vol. i.) In addition to the cases there described, may be mentioned one which was brought before the Med. Chirurgical Society by Mr. Solly, and published in vol. xxiii. of the Transaction.s (p. 437.). The subject was a female who had never bori}e children, anil the fragility of the bones :ip- peared at as early an age as twenty-two. She had violent pains in the back, and a white sediment in the urine. At the age of twenty- four, the spine began to yield, and she had rheumatic pains in the head. At thirty-six years, the catamenia ceased, and the patient began to be unable to walk or stand, and had great pain ; the greatest deformity being then apparent about the hips and shoulders. The bones of the head then became thickened, and those of the lower extremities more curved, and fractured by the slightest force ; but the urine at this time was clear and natural. The patient died, worn out by the disease ; and post-mortem examination showed the long bones to be reduced to mere outer shells, which could easily be cracked by pressure with the linger and thumb. The interior was filled with grtimoLis matter, of hues varying from dark blood to light liver-colour. Both the femurs were broken, the tibi® and fibula; bent, the spine much curved, and the pelvis extremely reduced in its diameters ; but the joints and cartilages were all healthy. The cranial bones were much thickened, and so soft as to be easily cut with a knife. The * Med. Chir. Trans, vol. xvii. p. 434. PELVIS. 191 diploe was obliterated, the Haversian canals enormously enlarged, and the osseous cor- puscles {lacuncE) diminished in quantity. From an analysis made by Dr. Leeson, the fresh bone contained,— in 100 parts ; animal matter, 18'75; water, 52‘08; phosphate and car- bonate of lime, 29’ 17 parts. The griimous medullary matter contained, — in 100 parts ; animal matter, 2P78 ; water, 73'.39; and phosphate and carbonate of lime, P83 parts. Under the microscope, Rainey found many granular, roundish bodies, about the size of blood corpuscles, and some fat globules ; — Simon, in a different part, could find no new or mature cell formations, but plenty of cyto- blasts, and a few young fat cells. Mr. Curling considers the softening of mol- lities ossium to be eccentric ; i. e., to commence in the centre of the bone, and pass outwards, affecting first the denser parts, and then the areolar extremities of the bone. He looks upon it as the result of defective nutrition, and that both the constituents waste in nearly equal ratio throughout. This author remarks that the pains always precede fracture or dis- tortion, and are not the result of these condi- tions. In one case, he observed copious svveats and salivation ; in another, a foetid unctuous exudation from the hands and feet ; in a third, foetid |)erspiration ; in a fourth case, that of an old woman of seventy, who had been bedridden for four years from para- plegin, there were no deposits in the urine. The pelvic bones might be cut with a knife, but the ribs and vertebras were less affected. The enlarged cavities and areolae were filled with red patches, resulting from injected vessels, and an oily medulla.*' Rokitansky gives as a characteristic of one form of mollities ossium (to which he applies the names oi“ osteo-malachia^’ or rhachitismus adultorum"), affects principally the bones of the trunk, those of the extremities being affected in a subordinate degree ; that it occurs especially in childbed women, and is often associated with cancer of the internal organs. This eminent pathologist also states that, in this disease, the bony corpuscles {lacunce) are found empty, and without canalicidi ; that the lamellar structure is also lost, and the structure satured with fat. The extract ob- tained by boiling differs, both from chon- drine and from the normal animal matter of bone, a circumstance w hich he considers to be the most remarkable characteristic of the disease. He states further, that this form of the disease is painful, malignant, and has never been cured. In some cases, the muscles were in a state of fatty degeneration. Mr. Dalrymple concludes, from microsco- pical observations of one variety of mollities ossium, that it W'as a simple (\ingo\A, malignant condition of bone. He found the areolar spaces enlarged by the absorption of their partitions, and great increase in the vascu- larity of the lining membrane. The “lacunte” were also enlarged, and the “canaliculi” con- * Med. Chir. Trans, vol. xx. p. SCO. siderably shortened, in the parts most affected. The red, grumous matter contained in the cavities, exhibited a large quantity of blood corpuscles, together with numerous nucleated and nuclear cells, with many cytoblasts, and some few caudate cells. Many oil globules and fat cells were also present. He con- siders the disease to differ from malignant osteo-sarcoina, in there being no deposit of new bone, and that the caudate cells, instead of increasing, become disintegrated, resolved into granular matter and oil globules, and finally dissolved.* Professor Paget considers, that there are two kinds of mollities ossium, in one of which he places the EhacMihmus adultonim, described by Rokitansky, as well as that just quoted from Mr. Dalrymple, where the bones are re- duced to a soft, flexible anti cartilaginous con- dition simply. In the other variety, which he considers to result, like fragilitas ossium, from fatty degeneration of bone, he wotdd place all the cases which have occurred in this country, including that of Rlr. Solly’s before described. Of the former variety, this patho- logist has never seen a specimen, and he does not, apparently, consider it either a malignant or a frecpient condition of the bones. His observations have led him to conclude that the grumous contents of the bony cylinder in this disease, of whatever hue — yellow, pink, crimson or dark red — ■ are composed of dis- guised fat. In part of a femur presented to the Hunterian Museum by Mr. Tamplin, he found free oil globules in large quantity, fat cells filled with oil, or empty, collapsed, and rolled up, and crystals of margarine contained in or without the fat cells. The colour, which was yellow, pink and crimson, was owing to the hue of the oil globules, nuclei and granules of the colla|)sed fat cells. There was no excess of blood corpuscles whatever. In a portion of a femur presented by .Mr. How- ship, there was left, after boiling, only a smalt quantity of white crystalline matter.'j" John Hunter remarked, in a case of mol- lities ossium, described by Goodwin in the Med. Observ. and Inquiries, that the bony structures were spongy, deprived of their earthy' matter, and so soaked in soft fat as to resemble a fatty tumour. In the pelvic bones of a female past the middle age, affected with the rostrated variety of angular deformity, I found, on making sections, a large quantity of a yellowish fatty matter contained in the areolar structure. This was particularly the case, also, in the head and neck of the femur, wdiich even after long maceration, had entirely a smooth and greasy section. On applying heat to various portions of these bones, in order to ascertain the pioportion of earthy constituents, they ignited and burnt wdth a copious blueish, fatty flame, with much smoke, and continued to burn freely till all the fatty matter was ex- hausted. The bones, which were very light, * Dab. .Jour. vol. ii. 18J6. + Lectures on iNutrition, Med. Gaz., 1847, p. 234. 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 oft' the organic components — 100 grains of bone, — gra. From the body of an upper lumbar verte- bra left — of earthy matter - - 31 „ the last lumbar vertebra - • 27 „ lower end ot the sacrum - - 24 „ ilium (cotylo-sacral rib) - - 40 „ ischium (near tuberosity) - - 30 „ pubes (near acetabulum) - - 33 „ head of the femur - - - 22 ,, neck of the femur - - - 2.5 ,, shaft of the femur (below trochant) 58 When vve compare the foregoing pro[)or- tions of the two constituents of bone with those given by Schreger, as the normal pro- portions of adult boue — viz., 20‘18 animal, and 74'84 earthy matter — the diminution of the inorganic constituents appears vei'}' 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 IMr. Solly before given. The femurs were perfectly normal in shape, as also were the bones of the lower leg, but the [lelvis was a rostrated one, the superior pubic rami being bent in the midtile 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 ])ubes separated at these points ; showing that the connection and continuation of the bone in these places was purely ligamentous, or liy organic matter, as if resulting from an un- united fracture. The sudden diminution of the hard con- stituents in the head anil 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 ]iro|)ortion of earthy matter in the pubes, as compared with the ilium, and in the sacrum and lumliar vertebrae, as com- liared 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 wdiole weight.* In the analysis given, in Eokitar.sky’s * Med. Chir. Trans, vol. iv. W'ork before cited, of a portion of lione af- fected wdth 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 yu-ecerfe 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 tile foregoing analysis was taken, the bones had, most probably, at some former period been much softer than they vvere at the time of death. 8uch 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 ossiuin, 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 reiulercd necessary, from the conse- (juences of which the jiatient 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 siqterior iliac spine to the other, cut the u|)per 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 f : — * Erfalirungen und Abliandhmgen ; and Appen- dix to Das Schrag Verengte Becken. f The measurements used by Naegele, (Rhineland or I’russian,) are verj' 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, IG lines only ; to the junction of the 1st and 2nd sacral pieces, 101 lilies. 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, oii(^ 21 /ines. 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 [iroducing 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 craniotom}', 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 li inch, becoming gradually narrower on each side. Ca;sarian section was performed, under which she sank. After death, the sub-pubic arch was found to be so much contracteil, that the sciatic rami were little more than i 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 Ctesarian 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 li inch ; the right sacro-cotyloid, to 2^ ; the left, to inch. The last lumbar vertebra and sa- cra! 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. * Me.d. Observations and Inquiries, vol. v. t Kssays, p. 355. It was very ingeniously advocated by Dr. Hull in his Letters to Sy mmonds, 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 ot the angular cordifonn 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 cordifonn of mollities ossium, yet that “of necessity, the softened adult pel- vis would take the shape called cordifonn, 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 draw s 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 [H'essed 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, _\\\ which cases the pelvis will assume the cordifonn shajie. 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 alxlonien, caused by a great increase in the normal forward bend of the lumbar curve; with an equivalent [jrqjec- tion of the sacrum posteriorly, from the hori- zontal position of that bone ; so that the plane of the superior pelvic o[)ening 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 CEesarian section. On being examinetl, the lumbar vertebrae M'ere found much curved forwards, and small, slender, and weak. The sacrum was placetl nearly horizontal from before backwards, its posterior part projecting very much behind (see fig. 120. «). 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 9i lines, ami 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 walacostcon. 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 up|)er surface (d), and measureil 8 inches 7 lines. From the anterior inferior iliac spine to the posterior extremity of the linea innominata, measured on both sitles, 2 inches. From the ischial tuberosity Fig. 120. Angular rickety pehiis. (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 1 1 lines. The height of the pubic s3’mphysis was 18 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 (h), 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 tlistance 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 |)ubis 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 di.stance 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 of mol- 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 aflected with the deformity. In the Anatomical Museum at Breslau, also, on the authority of Professor Betschler, is another example of this kind, exhibited by the jielvis 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- i'ormity in rickety ])elves, but in a minor degree of rlistortion.* In the Musetim of King’s College, London, are two rickety pelves of children of about from four to six years old, both of which are aflected with angular deformity of the pelvis. Fig. 121. Angular child's pelvis 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 ike acetabula at the line of junction of the two upper pieces of the innominatum, and not in the sujjerior branchjof the pubis itself, as in m.ost of the cases resulting from mol/ities 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. 3d23.), in wdiich it has bent outwards, instead of inwards, and thus is produced an elliptical distortion of the pelvis. This skeleton is from a young subjecf, in wdiich 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 acetubulum 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- ward 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 pel vic 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- iical 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 molUties ossium of adults, and commenc- ing after the pelvis has attained its adult de- velopment and consolidation, w'hen the bend most commonly takes [)lace 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 distinguishingmark between the angular pelvis resulting from rickets, and that of the adult inullitics ossium. Whether, on the other hand, the adult pel- vis, softened by moltities 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 perpentRcular 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 vertebrm, in the tho- racic cavity, at the level of the sterno-xiphoid articulation (see fig. 122. a, a). In the most easy standing position, this centre of gravit}^ is placed directly above that of the ivhole body, at the sacro-lumbar articu- lation (a, c) ; so that per|5endicular 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 19G PELVIS. necessary that the line of gravity of the whole body — viz. that from the lower centre — should Fig. 122. A. Di.igram of the lines and centres of gravity of the trunk, a h; and of the whole body, cd. B. Oulline of the lines of pressure in the pelvis and legs in the ovate rickety distortion, during the standing posture. — a h lines of direction of the pressure of the heads of the femurs in the ace- tabida, — upwards and outwards. c. Outline of the pelvis anil legs in the angular rostrated pelvis of the adult, resulting from nioUi- ties ossium. a h, a c, direction of iiressure in the acetabula when the legs are not deformed, — uptvards and inwards. T>. A similar outline in the angular rickety pelvis of the child, wdien the legs are bent outwards, — di- rection of pressure inwards. K. Outline of abnormal antero-posterior curves of the spine, pelvis, and legs, a h, direction of the pressure in the acetabula 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 thesetwo lines falls upon the muscles and ligaments of the posterior part of thespinc,and acorresponding strain u[)on their attachments to the sacrum and posterior ]iart of the pelvis. This instance may be taken as an example of many others, in which the me- chanical |K)sition of the line of gravity in- dnences muscular action, the effects of both falling upon the lines of pressure and support in the [lelvis. For the preservation of the sitting position, it is only necessary that the line of gravity of the trunk (a h) 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, wdiich prevents it etjually from starting outwards or pressing inwards at the extremities ; that for the cot}lo-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, anti |)laced 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 hcaa of the femur. The cotylo-sacral portion also sustains, in addition, its upward and backward [tressurc. 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 {fg. 122. e). The next effect is to produce lateral curves, which present generally their concavities towards the line of gravity, anil 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 dn[)lication 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 S[)ine low' down, will also have its effect npo.i 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 chi.nges from mechanical pressure, there is, in this softened state of the bones, the powerful effect of combined muscular action. The influence oi continued posture on these changes will be found to be the origin ol most of the differences of form we have seen in pelvic distortions. Let us consider the effects of mechanical position and muscular action m the recumbent, — sitting, — and standing posi- tions respectively', on the softened pelvis In ti/ing upon the back, the softened pelvis PELVIS. 197 will have a tendency to become flattened antero-postei’iorly, 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- bala and increase the transverse diameters. This I ap|)rehend to be the commencement of the elliptical pelvic deformity, wdiich 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 tlie softening be great, and the position long-continued, the sj'mphysis pubis would also sink, producing the hour-glass form of [)elvis; a disposition which would be increased by the traction of the levator ani and weight of the bladder. There would 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, w'ill cause the lateral pelvic arches to yield and bend inwards at the cotyloid line of junction, in children as yet unosslfied, and produce the first bend or tendency to tlie angular deformity. The effect of these first impressions are, as Dr. llamsbotham 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 t\\e 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 elUjitical 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 backw'ards, 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 bj' the action of the powerful erector spinas muscles, and psoas and iliacus muscles, exer- cised in keeping the trunk erect u[)on the [lelvic lever (see fig. 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 pube.s upwards still nearer the sacral promontory, tlimiuishing 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. Jiut when the lateral pelvic arches are al- ready impre.sscd 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. Kigby 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 side only has been [iressed inwards bv the constant use of the lateral recumbent |io- 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 acquiretl 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 elli[)tical distortion. This effect is also contributed to in like manner, under the same circumstances, in the standing [losition, by the pressure being greater and more frequent upon one femur than the other ; and thus we have produced a sort of oblique deformity, of which I 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 deformit3’. 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 tow-ards the right side,and the lumbar curve and sacral projection towards the left ; so that the line of gravitv, and o 3 ' J98 PELVIS. consequentlj’ 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 ami 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- pnbic 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 vertebrre 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 dilferent “ 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 inclniles all the pelves which present a want of symmetry at the sides under the general term ol 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 saci um 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 the 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 backw'ards along the cotylo-sacral rib, which is the principal line of pressure, and, 2nd, inwards on the lateral [lelvic 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 (Jig. 122. u,a,b), then the |)ressure inwards of the heads of the fe- murs upon the lateral pelvic arches is taken off, there i.s traction instead of pressure on the puliic 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 fibulae bent much inwariis, 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 adiluction 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 siqiport the erect posture — viz., the great glutei and psoae, will be such as to increase the deformity (see Jig. 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 Of 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 xvpward and hncliward pressure, and the deformity is increased by the upright position (j?g. 122. c, ab,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 {fig- 122. u, a 6, a c). Naegele observes, that when the lower e.xtre- 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 e-Kperiments 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 j)roportion 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 cases, to its full extent, seem to be the first to give way in the more complete and rapid softening of “ inolUftes ossium 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 efifect 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 psote and iliacus muscles, and the ischial tuberosities and trochanters approxi- mated by the pressure of the great glutei, which, aided by the pyriforrnes, 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 partial 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, § 44-t. 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 fig. 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 sufTer the full-sized fetal head to pass entire. 2nd. Those through which delivery may be accomplished “per vias nnturales,” by means of premature labour, craniotomy, or mutilation of the fetus. 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 fetal 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 fetal head can pass entire : — Diameters Conjugate. Transverse. Rnmsbotliam, Churchill, Lee, and 7 „ , . , ■ most obstetricians - - j Aitken and Osborne . - - 3 „ „ sufficient. Josh. Clarke Si „ „ „ Burns, Davis, and Le Roi - - 3i „ „ ,, Barlow (Essays) - - - - 2f „ „ „ Busch (Berlin) - - - - 2ito3 „ „ 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. Ramsbotham - - ... If ms. by 3^ ins. or Osborne, Hamilton, and Gardien - ,, ,, 3 ,, Davis and Barlow - - - H >> l^atinf. outlet. Baudelocque - - - - 1| »> » Burns, Hull, and Churchill - 1? jt « .» Dcwees - - - - - 2 ,, ,, of ins. O i 200 PELVIS. In these cases, acconling to Ramsbotluim, it is rare that tlie transverse diameter does not exceed three inches. Less room is recinired if the brim alone be distorted, according to tlie same author. All pelves contracted in their diameters be- low the measurements given in tlie last list may undoubtedly be considered to require, for the delivery of a foetus of viable or full-grown size, the abdominal section. Dr. Ilobert 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 inch at the brim, this author considers that abortion should be induced before the fifth month. According to Kitgen, 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 f) lines ; in the thirty- fifth, when 2 inches 10 lines; in the thirty- sixth, when 2 inches II lines; and in the thirty-seventh, when exactly 3 inches. When above 3 inches, the case should be left to na- ture. Harlow thinks that premature labour should be induced when this diameter is con- tracted to 2J- or 2f 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 Caesarian operation. In a table given by Velpeau j-, 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, D inch; in twenty- three cases, 11 to 2 inches; in twenty-five cases, 2 to 2;j- inches; and in five cases, 2^ to 2f inches. These, wdthout 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. 7'/m “ pelvis oblique ovuta," or ohliquelij 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 ciiaracteristics {see fig. 123.): — I. Complete ankylosis of one of the sacro- iliac joints, with coalescence of the sacrum and ilium, generally leaving no cicatrix nor line of .luncti’in. — 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 tlie linea innoininata, contraction of the sa- cro-sciatic notch by the ankylosis, and con- traction of the lateral parts of the sacrum and" ilium com|)osing the sacro-iliac junction. — f. Shifting of the sacrum towards the anky- * Essays, p. 3.51. t Traits des Accoucliements, p. 457. losed side, and twisting of its anterior surface in the same direction, together with removal of the jnibic 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 sym|)hysis and acetabulum, its distance from the former varying with the degree of distortion. The bodies of the lower lumbar vertebrae are also, more or 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 ank3'losed, Naegele found the pubic bones widely divergent from each other. So that, on this side also, these jjelves 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 in the diaiueter which extends from the normal sacro-iliae joint to the op])osite acetabulum ; while it is not con- tracted, hut 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 ajjpearance of an oblique oval (or oblong), the longest diameter of which corresponds to one of the oblique [)elvic diameters, and the shortest to the other oblitjue diameter. From this ap- pearance of the brim he was led to ai)ply 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 siqjerior 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 lcs.s narrowed, and turned towards the thigh of the ankj'losed side. That the contraction of the sa- cro-sciatic notch, and the approximation ofthe sciatic spines, is proportionate to the degree of distortion. And, lastly, that the acetabu- lum of the ankylosed side is directed mo:-e 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. 20! opposing ones ; the ank3'loseJ innominate bone appearing as if pushed upwards. A remarkable peeuliarit}' of this deformity is, that, with the exception of the difference in the side where the anky losis had taken place, the pelves affected with it were extremel}' 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 promontorj' could not be reached by the finger. The patient was delivered, on the third day, with extreme difficult}' by the aid of the forceps, and died fifteen daj's afterwards from puerperal fever. The pelvis was found affected with the oblique deformity, but in strength, weight, and texture perfectly healthy {fig. 123.). The sacrum was Fig. 123. composed of four pieces onl}', and measured in length 2 inches 11 lines. The coccj'x 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 lines. The same measure- ment on the right side amounted to 5 inches 4 lines. At the hrlm 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 - 4 7 night, ditto, ditto - - 3 5 From the sacral promontory to left acetabulum - - 1 10 From ditto to right acetabulum 3 f> 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 11 „ „ ischial spines - 2 114 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 IMilan, 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 ankj losis, 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 thesacrum is imperfectly developed. The left oblique dia- meter is nearly 1 1 lines less than the right ; and the right sacro-cotyloid di.stance, 1 Onlines 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 lOi lines. One of them, in Naegele’sown collection has six instead of five sacral pieces. In none of these three jjelves, 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 PELVIS. 202 ankylosis of the fight sacro-iliac joint, but no atfophy of that side of the sacrum, thoiigli tlie oblique deviation was present in a small tlegree, the right innominate bone being a little more elevated, contracted, ami 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 e.K- 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 |)clvis in which both the last transverse processes were enlarged and bifur- cated ; the right being articulated by fibro- cartilage to the corres[)onding lateral mass of the sacrum, and the left (the side on which the sacro-iliac coalescence existed) similarly articidated 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 sitle-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. J lie bad seen two others similarly deformed, and mentioned examples in the collections of Sebastian at Groningen, and Vrolik at Amster- dam, anil many more in the Pathological Mu- seum at Paris, and others mentioned by Creve and lletzius. Such irregularities of the sacrum are not uncommonly founil. A young female pelvis is described by Dr. Knox as presenting an example of the ob- liquely defonned 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 vertebrm 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, ilefonned on the left side, and presenting a large exostosis on the last lumbar vertebra. In hisown 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 vvould pro- duce, if the specimens were entire, the oblique * T.afel xi. Das Schriig Verengte Becken. t Num. 10., tafel iii. Op. cit. j Heidelberg Klin. Anna!., 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 obliijue diameter of the distorted pelvis ; but when in the [)elvic 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 res[)ects, 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 inches, may appear, in the living subject, to be contracted to'2^ 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 j jq one side to the posterior su- p g j^ches. perior iliac spine of the other J 2. From the anterior superior iliac! from 10 s|)ine of one side to the pos- !- lines to 1 terior superior of the other J in. 1 1 lin. 3. From the spine of the last lum-'j from 8 bar vertebra to the anterior [- lines to 1 superior iliac spine J in. 4 lines. 4. From the trochanter major of! from 1 in. one side to the posterior su- p to 1 in. perior iliac spine of the other J 7 lines. 5. From the lower border of the! from 7 pubic symphysis to the pos- j- 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 luhich the sciatic tuberosity is nearer to the opposite posterior su- pei'ior 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 luhole 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 ejiiphysial sacral pieces, which form the auricular surface, appear in the ob- lique deformity to have failetl 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 ankHosis, 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. Rigby inclines to this theory, and thinks that ulcerative absorption must have existed in the joint, though probably in early- life. PELVIS. 201 Since we know that the foetus in utero is subject to similar pathological changes to those of childhood, it seems |)robable 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 consecpient upon this process in Joints — such as ankylosis, happening at a period of immaturity, coincident with, or consequent u|)on, an arrest of development in the structures implicated, and probably having the same ultimate cause. The three cases before quoted from Nacgele, in which the deficiency of the sacrum and the oblicpie 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 separate!} and indepen- dently of each other. These cases also prove beyond a doubt, that the sacro-iliac ankylosis of itself does not jiroduce 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 ank}losis 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- meti'ical one-sided distortion in the instances before alluded to, presents many differences to, and more variations of form than, the defor- mity under consideration. Tue mechanism of this deformity in re- spect to the bne 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, consequetitlv, flattened only, and not indented, the principal yielding and inward bend a|)pear- 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 Eokitansky, arising from a coa- lescence of the base of the sacrum with the body and transverse process of the last lum- bar I'ertebra, 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, am! describes a larger and shal- lower curve of the ‘Tinea 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 vertebrae are rotated, and their curve inclines to the opposite or smaller siile, 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 to wards the abnormal side. I have met with tw'o pelves presenting this abnormality. In one, that of n female, which is in the collection of Dr. A. Farre {Jig, 124.) Fig. 124. Oblique pelvis Jrom sacro-lumlar coalescence. the left half of the sacral base is ankylosed to the corresponding side of the body and trans- verse process of the last lumbar vertebra, v\ hich 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 ; aiul the corresponding half of the sacro-lum- bar fibro cartilage remains unossified. The last lumbar spine and laminEe are connected with the sacrum by very thin plates of bone, but preserve their own distinct outline. There is 710 ank\'losis of the sacro-iliac or lumbo-iliac Joints. The true sacral promontory projects little, but a prominent false one is formed by the last luml)ar vertebra. The sacrum is short and small, but presents four distinct sacral holes, and five jiieces. 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- inoveLl about i or | of an inch to the right of the median line. The other pelvis is that of a 7nale, 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 leftside. The true sacrum is large and w'ell 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 siiecimen. PELVIS. 205 Wliether 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 wbich can only be decided by ab- solute comparison of the specimens. A greater or more advanced development of one side of the pelvis tlian the other is said by 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 ovata” and which is also often seen between that of the true and false pelvis. Pelvis obstructed bp 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 vertebrm, as in a case describetl by Nagel in 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 follow'ed 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 Cffisarian sectiou was performed ; and the patient died soon afterwards. The tumour was found to be 7 inches long by 6 in. broad, reaching as high 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 showerl 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 aboirt 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 fig. 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. symphy'sis. 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 li 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 fetal 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 iiTan unmarried female lunatic, and grew from the posterior surface of the pubis, producing retention of urine.* Las- sus describes processes of bone, of a sty loid shape, projecting from the posterior surface of the pubis towards the bladder.']' 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 Pinteus, Ruleau, and Portal, from an anky - losed symphysis pubis. One is alluded to by Naegele, which was as * Guy’s Hospital Eeports, No. 14, April, 1842. ■j- Patliologie Chirurgicale (Paris, 1805, chap. 80.). 206 PELVIS. large as a filbert, projecting from the ischium 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 Trailc. Dr. A. Farre informs me that an osseous exudation from the anterior surface of the sacrum, consequent upon disease of that bone, bail 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 [telvis, in tlie 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 [)rojections 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. Rheitmatic and gouty patients seem to be predisposed to exostosis. The influence of such exostoses upon par- turition approaches closely to that of deformed jrelvis, in the contraction of the diameters and the danger or impossibility of their removal. The difftcidty of distinguishing them, wdien 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 Uimours sometimes pro- duce [lelvic obstruction, and generally grow from the joints or ligaments. One case oc- curred to Grimmell of 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 I f lb., attached to the periosteum only of the right sciatic spinous pi'oeess 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 “yjer va- giiinm.” 'I bis characteristic will distinguish these tuiuoiirs, in diagnosis, from exostosis ; tlieir partial hardness, from fibrous tumours ; their immobility, from tumours of the soft parts ; and their attachments to the side of the pelvis, from the faMal 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 1803 (vol. i. p. 20 ). Tlie 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 w’as 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, anil interposed between the bones and viscera, but wdth 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 aftervvards safely delivered and recovered perfectly well and very sireedily. The tumour was 14 inches in circumference, and weighed 2 lbs. 8 ounces. It grew from the right side, and filled the whole cavity of the pelvis so com- |)letely as to admit of one finger only being passed between it and the |)ubis, 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 wdiich 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 fcetal head and tumours of the soft parts, by the immo- bility of their attachments ; tfom 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 moUities ossiuni. 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 Ankt/losis 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 sympliysis. 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 sacroAiimhar 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 jjathological 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 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 Rokitansk}', 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 ossific 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 right 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 of ankylosedyjjiiic described by J. P. Mitchell, and given by Hull in his 2nd Letter, the whole of the fibro- cartilaginous disc was 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 hi]) joint, — all these circumstances indicating a rheumatic origin. Ossification of the ligamenium arciiatum is also mentioned as sometimes interfering with the urethra. Cases of imperfect ankylosis of the pubic joint are also mentioned by Siebold, Voigtel, Walter, and Bonnard.^ All writers agree that ankylosis of this joint is rare. Dr W. Hunter had never seen an instance of it. O.ssification 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 gi'eat 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 seqoaration of the bones at their articular surfaces. This, as a pathological jjrocess, takes place most frequently by deposits of pus, as a consequence of puerpal fever, which may entirely destroy the joint, and sejrarate the bones. From its moi'e exposed position and more open structure, this change has been most frequently observed in the symphysis 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, more 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 [)elvis 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 1 to f of an inch. The pubes are more ele- vated than normal, with their articular ex- tremities turned outward, and the symphy- * Obsei'v. Anat. Path., b. i. p. 115., tab. 8. t Journal de Med. de Paris, 1778. t. xxxix. p.433. j Compend. of Human and Corap. Anatomy. 208 PELVIS. sial surfaces forwards, by the action of tlie 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 residting diameters are; — antero-|)osterior, from the sacral promontory to the inter-pubic ligament, 4 inches ; the inter- cotyloid, inches ; and between the sciatic tuberosities, 61 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 entire'y wanting, and the lateral parts of the pelvic bones are fuseil 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 cones|iondig lower extremities ; or these parts may be stunted or coalesced. Injiuence of hip-joint disease iij:on the pelvis. — Caries anil necrosis of the [)clvic bones, although sometimes resulting idiopatiiically, or from bedsores and abscesses in the muscular sheaths or lymphatics, yet chiefly occur as the consequences of coxatgia, 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, ifoccurring 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 iibout 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 irregtdar 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 Sdiambeine. Berlin, 1782. t Bathological Anatomy, p. 259. Sydenham Societv’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- nominata. 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 ilisplaccd 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-i 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 lather 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/ni 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 s[)inal 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 iinvards 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 [)soas 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 dift'erences, as already explained in the fore- going pages. Fr.vcturks and Dislocations ofthepekic hones. — The sacrum, according to Boyer,is les.s frequently found fractured than the other pelvic bones, because of its thicknes.s, 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 injui’es 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 wull 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 bone 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 ofl‘ 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- lacation 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 S7ipp. 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 symphysis 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- j)laced 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 {Jig. 126.). Fig. I 26. Fracture of the pubis and acetabulum. This fracture, accompanied by that of the superior pubic ramui, 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 innominatum. 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 conmiinuted and spicular fragments in the true [lelvis, 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 j)eritonitis carries off' the |)atient, 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 ])lace from the torn vessels, (tangrene may, in these cases, succeed to a great extent, and destroy the patient. It is these injuries, and their coiiseipiences 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 e.xtremities, 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- wai'ds on the sacrum, and at the same time sejiarated 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. (n another case, the posterior part of the acetabulum was broken off', the fr.icture pass- ing across to the pubes, both innominate bones being broken arul displaced, and the femur dislocateil. The pubic symphysis was seiiaraterl about au inch, the fibro-cartilage adhering to one bone only. The knee and foot were turnerl inwards, and the whole limb shortened two inches ; but it w'as 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 CtEsarian 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 supfiosed 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 pelvis, 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 oblique ovaia of Naegele. A preparation of this kind is mentioned by Dr. Ramsbotham, as existing in the Museum of University College. Fublioguaiuiy. — Naegele, schrag yorengte Beckeii (and' Appendix). liighy. Midwifery (in Tweedio’s I’ract. Jlediciiie, vol. vi.). J)r. liohert Lee, Lectures on I’artiirition (in bond. Med. (Ga- zette, l«4o.). Ihdl, Defence of the Cwsarian Sec- REPRODUCTION, VEGETABLE (Vegetable Ovum). 2il 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). Paget, Lectures on Nutrition (in Med. Gazette, 1847). Meckel, Ma- nual of Deserip. and Pathological Anatomy. Lever, on Pelvic Tumours (in Guy’s Hospital Reports, April, 1842). T'e/peuK, Trai'te 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 Algm and Fungi were involvetl 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 ap[)earance 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 ; w>e 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 be the natural order of complexity of organisa- tion. A second result of the same causes is the confcision 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 iqton 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 [dace. 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 term “ 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, whicli 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 |)arent, and still umler 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 ; namel}', as expressing not only that it will, if it live long enough, transform itself into an embryo, but that it presents itself unifoimly in the same species under the same anatomical condi- tions. The term “ vegetable ovum,” [ilaced at the 212 REPRODUCTION, VEGE'I head of this article, is employed in order to connect it with tlie preceding one on the “animal ovum,’’ to which it is intended to form a sequel. In its usual acce|)tation in vegetable |)hjsiology, the word means the generative product of the Phanerogamia only. And even if we were to extend its meaning so far as to iucinde all those varieties of germ, for the development of which two organs mutually dependent on each other for the ac- compli-shment of their reproductive functions are necessary, we should still he obligeil to disregard one half of the vegetable kingdom. Part I. Alg/E, Fungi, and Lichens. 1. licp7'odiir/ion hj means of ospores. — Among the most sinqdy organised iufusory 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 Euglcna viridis, which is so common in all our shady ponds, though in active motion during the greater |iart of its life, manifests at other |ieriods a condition of plant-like repose. The contractility displayed in its rafiid and ever-varying changes of form is a property which, there can be little doubt, manifests itself frecjuently among undoubted plants ; * so that the transition from the Eu- glenas to many of the forms of the Proto- coccus-like Algas 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 [lossess 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. I'ABLE (Vegetable Ovum). pear-shaped, fusiform, or oval ; at the same time they are endowed with the power of F\g. 127. Cell of Protncnccvs ]>lavialis. containing moving Zoospores, about '20 eliam. (Cohn.) active motion, and are furnished with a pair of vibi'atilc cilia, emauatiug from their anterior Fig. 128. Free Zoospores of the same. (Cohn.) extremities. In the course of their further development, these actively moving bodies, which weshallcall Zoospore.s, become invested with a distinct membrane. This seem.s to be a [ireparatory 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 callable, 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, hut 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 (Ascidium acuminatum). 'I his species, which is found attached to stones or other objects, resembles the Protococcus piu- vialis in its general form. By the division of the protoplasma which lines its cell-wail, numerous zoos[)ores 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). 213 tions. In the liistory of their tievelopment we have an epitome of that of all the more simple Algae. In the family of Protococci the type may be said to be inchided to which all the green and olive-coloured Algte, with the exception, on the one hand, of the Des- mideae and their allies, on the other of the Fucaceae, may be referred. Among the Des- midete, 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 into a central mass, becomes divided into numerous secondary masses, the number of which is always a |)ower 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 zoos[)ores 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 Algte, many of which, though they are but little elevated above the Protococci as regards their struc- tural elements, present a general a[)pearance 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 Verjiuigung in der Natur) as well as by Caspary (Butanische Zeitung, 1850, S. 780.). The description in the text is after Braun, with whom Caspary agrees in every important par- ticular. extremities of the tubular branches. In these situations the cavity of the tube becomes completely filled, while at some [mint 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 3'et 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 bj' the Germans. A minute aperture, or pore, is Fig 129. a, termination of tubular frond of Bryopsis crowded with zoospores; 5, the same, after the escape of its contents. Each of these e.xhibits the lateral pore ; c, fully formed zoospores in active motion. a and h 150 diam, c 200 diam. then found at the extremity of the nipple-like projection, apparentl} 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 confer- voids, the frond consists ofa 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 Bryopsidete, the opening by which the zoospores make their exit, being situated at the upper part of the cell, imme- diately below the septum, which diviiles it from its successor. In other cases (as in Mi- crospora), the zoospores escape by a kind of * Thuret, Reoherclies sur les Zoospores des Al- gues. Aim. des Sc. Nat. xiv. 217. -214. REPRODUCTION, VEGETABLE (Vegetable Ovum). ilislocation of tlie tulie, 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 [irotoplasma is increased in quantit)’, 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 he closely related in form and structure to the Bryop- sideae, we observe this important difTerence, 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 Solierf, in which the relations of the s])ore cases to the frond are similar to those which exist in Derbesia, although the forms presented by the organs in question are infinitel}' various. 7. The researches of the authors above alhuled 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- os[)ores, 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 CEdogonium, 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, wliicli are arranged in the form of a crown. (See Thuret, 1. c. p. 2ZG.) t Derbes and Sober, Sur les Organes reproducteurs des Algiies. Ann. des Sc. Nat. xiv. 200. in the arrangement of their cilia. These organs, which are always two in number, are Fig. 1.30. Sporangium of Ectocarpus slliquosiis, 240 diam. Ectocarpus is one of the simplest forms of olive- coloured Algce, 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 ihe 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 (oo-iporangia, Thur.). which have been frequently described as single spores, in reality contain numerous zoospores. The other form {tricJio-sjoorangium, 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 regarils their reproductive func- tions. The sporangia (trichosporangia) of Cutleria, not only differ from those of other genera, in resi)cct of their greater size, but Fic’. 133. REPRODUCTION, VEGETABLE (Vegetable Ovum). 215 present well-marked distinctive peculiarities of structure. The frond consists of olive- coloured, irregularly divided jiabvU'i, on each Fig. 131. the resulting cavities, zoospores are to be found, which, though they altogether resemble in structure those of the other olive-coloured Algae, are about three times as large. The supposed antheridia of Cutleria communicate to the tufts of which they form a part, their 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 a, a portion of one of the tufts, or sori, of Cutleria, showing the mode of attacliment of the filaments which support the sporangia to tlie 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 {sori), 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 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. Contents of antheridium 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 ve.sicle, 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 apjdied, as they occur in the Fucacete. The fructification of these plants is, as is well Fig. 134. a, antheridia from the concepfacle of Halidrys 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, I’ 4 216 REPRODUCTION, VEGETABLE (Vegetable Ovum). or hermaphrodite, according to the organs which they contain. The male concepta- cles [)resent in tlieir interior an arrangement of hranclied filaments, or hair-like organs, whicli, taking their origin from the surrounding cellular tissue, converge towards the pore. At the summits of these filaments, the so- called antheridia are su[)ported, which consist of little ovoid transparent vesicles. They contain, in their early condition, a granular j)roto])lasmic material, but as they approach maturity, the so-called antherozoiils make their appearance. These last are hyaline corpuscles, not exceeding about g of an inch in their longest dimension. Each con- tains a (;ranule of a greyish or reddish orange colour, from which the organs of locomotion emanate. The form of the zoids differs ac- cording tothegeniis. InFucus, they are bottle- shaped, and each possesses a pair of cilia, one of which, the shortest, is directed forvvards from the neck, while the longest emanates from the coloured [mint and is pointed back- v\ards. In Halldrys, the zoid is ovoid or spherical, and the longest cilium is directed forwaixls. In Fucusand several other genera, the trans[)arent vesicle in which the zoids are immediately contained, is itself enclosed in a second of similar form. At the [teriod of matui'itv this last gives way at its apex : the internal sack is ex[)elled, and at once finds its way towards the external opening. In the meantime its delicate membrane disap- pears, and the liberated zoitls commence their active motions. 9. Although the antherozoids of the Fu- coideas differ from the zoos|)ores of the other olive-coloured Algae, in their not possessing the [tower of germination, there are yet remarkable [Joints of corres|)ondence between them, in their form, sfructui'e, and mode of develop- ment. Both are composed of a hyaline [iro- to[)lasma, and the [losition of the coloured granule, as well as the arrangement of the cilia, corres[)onds. They differ, in the first [jiace, in size, and secontlly, in respect of the chlovo- 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 zoos[)ores display the power of germi- nating without the slightest reference to the presence or absence of the secretion of the su|)posed male organ. Further, if, as all obser- vations which have been hitherto made, tend to prove, the zoospores of all the green Algae, anti 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 Fucoideas, we have certainly no evidence whatever that the antheridia [jerform 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 Bryopsidese, from which the Vau- chcritE 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 [jrotoplasma in the rounded terminations of the branches of the [)lant. This condensation is accompanied with an enlargement of the cylindrical filament, which soon appears club-shaped, and is com[)letely occiqjied by a confused and opaque dark -green mass. Shortly afterwards a septum is formed, which limits the terminal portion of the tube. Within the se|)arate 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 [tossesses 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 [jart 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 Fucaceas. In the case of the latter, the accuracy witli 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. ties Sc. Nat. 2'' S. xix. 269; Vauclier, Hist, des Conferves d’Eau douce, p. 24C; Karsten, Die FortpHanzimg der Conferva fontiualis, Bot. Zeit. 5 Stuck, 1852. REPRODUCTION, VEGETABLE (Vegetable Ovum). sj17 theridia ($ 8.), we described the general form of the conceptacles. In the monoecious and dioecious Foci, the female conceptacles are distinguished from the male by their olive colour. The spores ai'e 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-eiglit 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 Vaucherite 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 d'stinct surface. At this point the resem- blance ceases ; the protoplasmic membrane divides, just as in the spore-cases of the zo- osporous Algse, 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- 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 Tlmret.) 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 is immediately followed by germination.* * For the histoiy 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 spheroidal corpuscles unen- dowed with the power of motion, if not incapable of germination. In tliis 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 218 REPRODUCTION, VEGETABLE (Vegetaislk Ovum). 12. In the process of the formation of zo- ospores in Saprolegnia, we have an intermediate step between that of the zoosporous Algm on the one hand, and tliat of a class of plants which is usually placed among tlie Fungi on the other. I allude to the Fungi included in the class Cystosporete of Leveille ; on the intimate structure of this, as well as of many other allied groups, there are as yet hut few re- searches. We 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 Algte than to the Fungi. We shall take Pilobolus as an illus- trative exanijde. 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 |)laut, the spore-cell displays in its germination, a tendency to develoi)mcut 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 (irotoplasma 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 |)rotoplasma, 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. J3ot. Zeit. 28 St. 1852. For further information on Achlya, see Unger, Linnma, 1843, p. 129. ; Nagell Zeit. t. rviss. Bot. B. i. II. 1, 2. Pringslieim, Nova Acta Ac. L. C. 1851. porting cell with such force, that it is thrown like a miniature bomb for several inches.* 14. The Fungi which agree in theirdevelop- 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, wliich Schleiden considers as characteristic of the Fungi. On the otlier hand, the analogies between Pilobolus and Vaucheria are of the closest kind ; even the ephemeral periods observed in tlie development and ripening of the reproductive apparatus, being the same. The root-cell of Pilobolus the inferior of the three of wliich 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. 13. licproduclwn 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 Synsporese 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. Rail’s 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 Vaucheriacese, 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 earlie.’ period in Closterium, than in any other genus. The earliest description is thatofMorren, 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 mem- * Cohn, Die Entwickeliingsgeschiehte des Pilo- botiis crysiallinus. Nova Acta Ac. L. C. p. 49G. 1851. REPRODUCTION, VEGETABLE (Vegetable Ovum), 219 brane.* Wlien 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 partiallygives 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 halfof 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 diam. 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 So. Nat. Sen p. 325. the conjugation of two individuals, only one of the halves of each empties itself, the other remaining unaltered.* In other families of Desmideae, the pro- cess of conjugation, although variously modi- fied as to its less important details, is essentially the same as that which occurs in Closterium. f 17. In the Zygnemaceae, confervoid plants, which seem to have a close relation with the Desmidete, 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 Desmideac, 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 Mr. Ralfs, who, however, assigns to them a difierent origin. (See British Besmidea, tab. xx\fii. 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 Desmideai, 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- rnidea', affords an effectual safeguard against their otherwise possible extinction. J Rratm has observed the germination of the spores in a specimen of Sp^Togyra setiformis which had been collected for eleven months. (Braun, /. 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 [>lant. 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 [iresent themselves in a somewhat different and ven" remarkable form. Here two cells, probably the rcsidt of a series of ilivisions, 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 tliffers in noVespect 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. I 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 Vancheria 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 paii's along the whole course of the older filaments. In every pair of organs, one elongates so as to form a closed 137. Fig. A. portiun of the tiibtilar frond of Conferva fontinalis, showiny the arrangement of the sexual repro- ductive orgems. About 30 diam. (Karsteu.) 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 adark- greeu-coloured globe, supported ou 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 tlie germs are represented; one of wliich is in con- tact, by its smaller end, with tlie tabular organ which occupies the centre. (Karsten.) with sufficient distinctness by Karsten’s obser- vatioms, that an actual interchange of the *_ Vaucher, Conferves d’Eau douce, p. 4G ; Pring- sheim. Annuls of Nat. Hist. June, 1853. (Trans, bv Mr. Ileufrey.) contents takes place. All that we learn as certain i.s, 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- ceiled 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, G Stuck.) The process of which the details have been so well described in the above memoir, was known to Vaudier, and is mentioned by him in liis “ Histoire des Conferves d’Eau douce” (p. 17.). See also Najgeli (Vergl. Algensyst. p. 175.) ; Has.sall (British Fresh- water Algoe. vol. i. p. 175.) ; and Thuret (Annales des Sc. Nat. 2nd Ser. 1843), who gives a figure illus- trative of the conjugation of Vaucheria hamata. In T\ polysperma, a species described and figured by Hassall (1. c. PI. iv. f. 6.), the spore-bearing organs are very much more numerous than the curved tubular organs, a fact for the explanation of which observations are as yet wanting. 221 REPRODUCTION, VEGETABLE (Vegetable Ovum). of 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 w’hich 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. f 21. Reproductive organs of the red Algce or FlaridecE. — 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 polpspore 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 perisporanghm, by the rupture of which the sporidia which are formed from the endo- ehromes of the filaments, make their escape. Other forms, which it does not seem neces- sary to mention, are observed : they all agree in one particidar, 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 simple, and consists of a globular or ovoidal cell, con- taining in its interior a central granular mass, * Priagsheim, 1. 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 days in rain water, exposed to the light. By this method a crop of Saprolegnia may he obtained at any season. t Braun. 1. c. p. 318. 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 a[)pearance of special organs, which are called stichidia, as, for example, in Dasya.* 2.3. 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 Griffithsia, or enclosed in a transparent cylinder, as in Polysiphonia, or covering a kind of expanded disc of peculiar form, as in Laurencin.” -j- According to the researches of Derbes J and Niigeli §, each of these cellules contains a spermatozoid. Niigeli 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 antheridium 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 sinqjle 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 w hich 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. II. Harvey, Nereis Boreali Americana, Part ii. passim. New York, 18.52. The best descriptions of the organography of the Florideaj will be found in the Es.say of Decaisne on the Clas- sification of the Algaj in the Ann. des Sc. Nat. 1842 ; and in Nageli’s Zeitschrift, f. w. Bot. Heft. 3 & 4. Zurich, 184(). f Thm-et, Ann. des Sciences Nat. S'"® Ser. xvi. 14. J Derbe.5, Ann. des Sciences Nat. 3“' Ser. xiv. 2Ci.; Thbse de Botanique, p. 25. Paris, 1848. § Nageli, I. c H. 3 & 4. S. 224. Zwei Benier- kungen, &c. Bot. Zeit. 1850. 32 Stiick. 222 REPRODUCTION, VEGETABLE (Vegetable Ovim). is composcJ of little bunches of hyaline cells, which are arranged round a central axis, Fig. 139. Antheridia of GriJJithsia, 30 diam. a, a kind of involucre is formed by a whorl of six verticillate branchlets, at the points of bifurcation of each of which is borne an antheridiiim ; b, 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 of an inch. From the above details it will be seen that great difficulties lie in the way of a compari.son between the reproductive organs of the Flo- rideae and those of other families. Niigeli considers them to present a strong analogy with those of the llepaticte, with which he places the Floridcac in a parallel position. We shall see, as we advance, how little ground there is for stich a view. The Floiidete 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 Characece, we are, as yet, able to [lerceive 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 jdace until spring. It * Vaudier, Mem. Soc. Hist. Nat. de Geneve, tom. 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 s|)rings a cylindrical cell, the axis of which is perpendicular to its inner surface, so that each cell approaches the centre of the S[)here 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 jiassing 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 tlie segments the antherozoids have escaped ; two are in the act of escaping : h, fully formed antherozoids. 400 diam. (Thuret.) divided by transverse partitions into a number of segments. In each segment or cavity an autherozoid 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 Algte in which the phenomena of reproduction have been more or less completely investigated, we shall fiml that all the instances of the occurrence of bodies to * For further information see K. Muller, I>ie Entwick. der Cliaracecn, Hot. Zeit. 1845, p. 39'!. Kaulfuss, Hie Keimung der Cliaracecn. Leipzig, 1825. Varlej', On the Structure of Chara in the Microscropic Journal. Thuret, Ann. des Sc. Nat. xvi. p. 18. 223 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 ovoidal body : it is composed of transparent, colourless homo- geneous plasma, throughout the whole of which, with the ex-ception 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 tlie form which they exhibit being that which is always assumed by starch, not only among the Alga;, 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 zoospoi’e 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- caceae, of the Floridete, 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 Floriileae, 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. Germs, whose development is dependent on the combination of two organs the reproductive functions of which are complementary each to each. — Of tliese 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 Zygnemaceas. 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 Florideas, the stationary spores of Sapro- legnia, and others, of which, as they are still imperfectly known, sufficient has been said in the preceding [>age.s. 32. Fungi and Lichens. — While, on theone hand, the Fungi and Lichens present an endless variety in the organs which constitute their re[)roductive system (receptacle), their vege- tative system {mycelium, stroma, flocci, hjpo- thallus, Sfc.), 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 com[)licated 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 tlie organs which constitute the reproductive sys- 224. REPRODUCTION, VEGETABLE (Vegetable Ovum). tem take their origin, and, as its i)resence 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 de[)ended u|)on, and arrange them in such a manner as to serve as a foundation for a general view of the subject. The* most sim[ily 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 multi[)lies by the budding out of its membrane at one extremity into a projecting nipjile, which soon becomes se|)a- 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 accjuainted with of one-celled Fungi, come the innumerable Hyphoviycctes or thread Fungi,so called because their rej)roductive, bears so small a proportion to their vegetative system, that it is in many cases altogether overlooked. The growing terminations of the mycelium fdaments them- selves become iiulividualised, 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 \vhich Schleiden considers as the character which distinguishes the true Fungi from the Lichens*; thelatterdeveloping“many spores simidtaneously 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, clidt- 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.j- In other genera, the per[)endicular sporiferous filaments are woven together into more complicated structures, the varieties of which it does not come within our present purpose to describe. As resjtects their component elements and the * Sdileifien places all the ascophorous Fungi among the Lichens. We shall find, as we proceed, that such an arrangement is altogether inadmissible. (Schleiden, Principles of Scientilic Botany% p. 157.) f Corda, leones Fungorum, tom. i. p. 21. mode in which the spores are produced, they do not diflfer from those noticed above. Fig. 141. Branching ^poriferous 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 perj)endicular 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 husidiiim with its four husidospores, along with two other sterile basidiu ( Geaster rufescens'), 300 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 atmos|)here; 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 {(Jeaster), for the purpose of illustration. 225 REPRODUCTION, VEGETABLE (Vegetable Ovum). 35. At the period of the formation of the spores, the receptacle of Geaster (fimbriatiis) is a solid body of a depressed spheroidal form. It presents for examination a central mass and a peridium, the tissue of tiie latter being con- tinuous with that of the former only at the base. The central mass or kernel is originally Fig. 143. Diagram of receptacle of Geaster fimhriatus. The kernel, a, is surrounded bj’’ its reticular mem- brane, which is indicated by the inner of the tw’O double lines. The outer double line corresponds to the resistant external layer of the peridium. The intervening space, b, 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 w'hich 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 cork}', 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 Fig. 144. 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 basidii have been shown, by careful observation, t< 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 Lt/coperdons, 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 lacuna 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. \Ve 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 theem 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- 226 REPRODUC riON, VEGETABLE (Vegetable Ovum). sistence and of a dark-brown colour ; the other white and opaque. The former, which cor- Fig. 145. Section of part of the receptacle of a TruJJle, ahont 200 flam. a, outer layer of the peiulium consisting of a resistant tissue of thick-walled cells ; b, inner layer of the same, formed of filamentous tissue continu- ous with that of i>, one of the venaa interna^, or iiar- titions by which the comp.artments (originally cavities) of the truflle are bounded. Portions of two of these compartments are seen with the thecaa and septate filaments which they contain. responds to the partitions widt h, in the young state of the truffle, separated the cavities, is continuous with the external tissue whicli composes the envelope or peridiiun, and con- stitutes the vena internte 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 landnae. These tubes, which are the terminations of the filaments of which the landnm 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. f ■" Vittadini, Monog. Tuberacearum, p. 2. et seq. t L. K. & C. Tulasne, Histoire des Champignon.? hypogee's, 11-50. 37. Theascophorous Fungi are represented in their simplest form by the Uredinem, a family which has been studied by numerous observers on account of the destructive pro- [)erties 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 u|)on which it grows parasitically, may be aptly compared to a pustule, a grumou.s-looking substance, occupying, as it were, the place of the pus. On more minute examination of the cavity, we find that it is hounded 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 j enlarged extremities of the mycelium filaments, j with which many of them can be distinctly | traced to be connected. Towards the base of ■ the cavity other cells are developed, resem- i' 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 interiorly, so as to form a tubular pedicle ; while in the club-shaped upper ex- tremity it is lined by a considerable deposit of granular (>rotoplasma, 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 Sphceriaceae, to which they are evidently closely related. The cyst is formed (Qicidium) of a single layer of roundish cells.’f^ 38. From the Uredineae 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 the.se plants more satisfactory and instructive than that of any other family of the class. The’ Pyrenomycetes are represented bv 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 * L. R. Tulasne, Reclierches sur le.s Urecliiiees, &c. Ann. des Sc. Nat. 3me. S. t. vii. p. 12. 227 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 w'hich they are con- nected. The thecae are obovate cells, the Fig. 146. Thecce 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. Fig. 147. Ripe spores of Cenangium Frangulce, 350 diam. The contents of the spores, as is observed throughout the higher Fungi, consist of a fluid loaded with oily granules. The thecte are arranged with their long axes perpendicular to the inner surface of the peritheciurn from which they spring, and are intermixed with a greater or less number of slender, cylindrical paraphyses. The whole peritheciurn is usually enveloped in the filamentous stroma or my- celium, from which it takes its origin. The Discomycetes are repi'esented by the Pezizae; between these and the Sphoerim there are dif- ferences of external foi’m, which, though they strike the superficial observer as important, are in reality trivial. While the receptacle of the Sphceria 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 ascophoi’ous mem- brane, which resembles in every respect that of a Sphceria. 39. Along with the Pezizm and Sphoerim and those allied genera which resemble them in producing their spores enclosed in thecae, there are other forms also included in the 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 ap[)earance 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 Sphceria, and are entirely occupied by a pulpy nucleus, which con- sists of slender branched filaments, often so long as to project considerably bej ond 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 I’Appareil reproductcur dans les Lichens et les Champignons, Ann. des Sc. Nat. 3me. S. t. XV. p. 370. t Nouvelles Recherches, &c. Comptes rendus, Seance du 13 Dec. 1852. 228 It KPRODUCTION, VEGETABLE (Vegetable Ovum). upon tlieir upper surface thecee ami paraphyses like those of a Peziza. In other genera M M. Tulasne found that the ascophorous receptacles are preceded by capsules which produce, instead of the linear sporules above mentioned, cylindrical spores ofa 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 S[)ore-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 ado[)ted with advantage. The minute, linear s|)orules, which are produced at the extremities of branched filaments, like the pai'aphyses of Sjihwria, are called spermatia. The cylindrical bodies of much larger size, which are borne each at the extremity of a stipitiform cell, are named stylos[)ores ; while the term spore is reserved to those which are formed in the interior of a theca. ^3. bis. In a third “Memoire” which has appeared since the above [)aragraphs 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 inyfg. I4S. 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(/?g. 148. a) resemLdes 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 {fig. 149. a) which it contains, are Fig. 149. group of stjdospores, with a fragment of the wall of tire receptacle in which they are enclosed; b, similar group of spermatia. About 300 diam. curved, crescentic bodies, supported on pedi- cles, which have an arrangement perfectly similar to that observed in Scutula. The receptacles or cupules in which thecte are [)roduced 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 {fig. 149. b), these being supfiorted 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. Part of a dead branch of Rhamnus Frayir/uJa, with receptacles of Cenangimn. {Slightly magnified') Vertical section of discoid receptacle of Cenangium, about 300 diam. REPRODUCTION, VEGETABLE (Vegetable Ovum). 229 represented in 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 the}' 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 Verrucarite, 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 thesurface 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 foliaceous 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 I'Histoire organographiqiie et physiologique ties Lichens, Ann. ctes Sc Nat. 3mc S. t. xvii. pp. 6. and 173. Fungi. From the surface of the inferior layer are given olT numerous laminar root-like Fig- 151. Vertical section of the apothe.cium of a Lichen {Par- melia aipolia) and of the subjacent tissue of the thallus, 200 diam. a, Lamina proligera, consisting of thecoe and para- physes ; b, 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 w’ith 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, spermogonits, 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 gymnocarpous Lichens. In the AngiocarpecE, 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 lamina proligera. It is formed of two kinds Q 3 230 REPRODUCTION, VEGETABLE (Vegetable Ovum) of elements : first, tlie pamphyses, which are linear, claviform filaments, composed of from Fig. 152. Section of fruitful thallus of Sticta })uhnonacea, 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 theca:, which are obovate vesicles, each containing, almost in- variably, eight spores. These elements are arranged side by side, their long diameters being perpendicnlar 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 supjjosing 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 theca; and para|)hyses, 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 ol the fully formed spore is best ob- served in those species in which it is largest. The s])ore-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 theca; with an elastic force often sufficient to project them to a considerable height above the surface of the apothecium; a fact, which M. 'fulasne 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 (joints, scattered at irregular intervals. The form of these organs. Fig. 153. Spermogonia of Scutula Walhothii, 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. Tlieir external envelope is frequently hard and crustaceous, and usually blackish. The cavity may lie 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- cejjtacles. 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 w’hole 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. 1860. S. 913. 231 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 stipitiforni pedicles or basidia. In their Fig. 154. Pycnidis of the same, about 150 d'lam. The stylospores are escaping from the upper ori- fice of the organ. (The figures from 143 to 154 iu- cliisive, are after Tulasne.) general form they resemble the spermogonia;, 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 57)0^ to of 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 spermogonise. 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; 5. 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 Pyreno-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 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 spermogonife of the Lichens. The stylospores are also formed in special organs (pycnides, and the corresponding organs among the Fungi), which (lifter from the last only as regards the structure of the parts upon which the spore is immediately sup- ported. Lastly, the receptacles which bear thecEe 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 Sphoeria, and the apotheciuin 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 most 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 mycdium, 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 theFuci,orof 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 thethecce or their contents, and on these important points, therefore, we must look to further ob- Q 4 232 REPRODUCTION, VEGETABLE (Vegetable Ovum). servations for the grounds on which an opinion may be formed. 33. The filth and last variety of reproductive organ mentioned above, is the basidium. The Mush rooms, along with another group of Fungi, whicli is distinguished by the possession of loculate rece|)taclcs, each locidus 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- sporeae. 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 com|)aring the reproductive organs of the one with those of the other. The basidiospore 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 pecidiar and uniform arrangement, according to which the spores are developed in fours at the summits of the hasidia. Second Part. Higher Cryptogamia and Piianerogamia. 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 Algte, Fungi, and Lichens, we have en- countered difficulties at every step. The extension of the same inquiry to the higher Cryptogamia and Piianerogamia is much more satisfactory in its results. “ The comparison of the history of the development of the leafy Mosses and Hepatic® on the one hand, and of the Equisetace®, Rhizocarpa®, and Lycopodiace® on the other,” says Hofmeister, “ has shown the most complete corresjiondence 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.” * 53. The higher Cryptogamia and Phanero- * Hofmeister, VergleifhendeUutersuchungen der Keimung, Entfaltung u. Fruohtbildung hoherer Cryptogamcn. p. 139. Leipzig, 1851. gamia form a series, which, commencing with the frondose or membranous Hepatic®, ascends through the Jungermanni® and Marchanti® to the true Mosses. At this point, the thread is interrupted, but is easily resumed, and fol- lowed through the Ferns and Lycopodiace® to the Rhizocarpe®. Between these last and the Phanerogami®, 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 regnlar 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) isdestined 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 ofi’ 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 /n'sfoV/fdfa and antlieridia, and thus forms the starting point of a new development. 36. 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 distributionof the spore.s. 37. Among the lower Hepatic®, the vegeta- tive system (frond) consists of a simple mem- branous expansion, which may be considered equivalent to wbat 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 earliest 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 l®vis) as one of the most simple of the Hepatic® in its structures, the fully-formed frond is a lobed expansion of succulent, dark-green parenchyma, the genera! 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. 833 REPRODUCTION, VEGETABLE (Vkgetable 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 anlheridia 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 right 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 tvvo vertical columns. The penul- timate cell of one of these columns next * The following description is abridged from Hofmeister in loc. cit. pp. 4 — 9. 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 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 antheridium of the same, 250 diam. ; b, lenticular cellules containing antherozoids, COO 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 Hepaticse 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). otlier ol)ject than the admission of the anthe- rozoids. tig. 137. Archegonium of the same, 300 diani. a, origin of the archegonium ; the shaded vertical row of cells constitutes the rudiment of the organ ; b, archegonium immediately before impregnation. 61. Second period. — Frtictijication of the ar- chegonia. In the greater number of archego- nia, development ceases at the point above described. In tliose 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. 138. 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 bodv, 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- lidar 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-sha[)cd ; 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 e.xtremity 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 preparatorp 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. 139 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 andelaters, — 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. Develojtment 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). 235 a quantity of granular mucus. Soon this last arranges itself in two masses, at opposite Fig. 160. a Original parent-cell of spores of the same, 500 cliam. 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 Fig. 161. /, 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 cavitv. 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 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. Jungcrmayinia frondoscB. — From Antho- ceros wepass 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 penod. — 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 oft’ 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, he. cit. pp. 10 — 20. 236 REPRODUCTION, VEGETABLE (Vegetable Ovum). of the young shoot. Soon after their origin, there is formed, by the continued growth of Fig. 163. Antherozoids of Pellia, 400 diam. (Tlmret.) 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, suiTounded 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 comi)leted 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 Archegonium of Jungermannia bivaricata at period of impregnation, 400 diam. Cellules containing antherozoids are obseiwed 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 entrance of 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 graaually enlarge without dividing. The result of this process is the formation of a central ma.ss 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 capsnle, 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 237 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. In this 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 w'hich 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 Hepaticse. In the higher Jungermannise, 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 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 the last-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 bj’agrowth 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 nevv 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. Jllosses. — 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- * Recherclies Anat. et Phys. sur le Marchantia, M^m. de I’Acad. v. xiii. p. 380. t Transactions of Linna:an Society, vol. xxi. p. 106. 238 REPRODUCTION, VEGETABLE (Vegetable OvlmL neina),* resembling in all its relations to the future [)lant, the mycelium of the Fungi and Lichens. 73. First ^icriod . — Germination of the spore.-f — 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, lienee results an entangled network of filaments of a brilliant green colour, which spreads over the moist surface on which the sjiores 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. Develoj)ment of the antheridia and arclie- 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 cither 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 re[>ro- 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- gonium corres]ionds so completely with what has been described in the Jungermanniae, that * From the very recent observations of Grbnland (Me'm. siir la Germination des Spores de quelques llepatiques, Ann. des Sc. Nat. S. xx.), it appears tlrat among the higher Ilepaticae 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. t Hofmeister, toe. cit. pp. G5 — 71.; Bruch & Schimper, Bryologia Europaja, Fasc. i. p. 5. it is unnecessary to describe it. The fully formed antheridium of Phascum is a club- Fig. 1C5. Section of termination of fruitful stem of Phascum cus]/idatum,oO 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. Develojtment 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 sales. 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, wliich is subjacent to it, but of that of the conical summit of the stem. In 239 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. 1C6. 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 106 from Hofmeister.) ers of cells from the central portion, a cavity of the form of a hollow cylinder, the axis of which coincides with tliat 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 now formed at the surface of contact of the two vesicles by which the original cavity is bisected. In the cavity of each of the result- ing nucleateil cells, two new ones make their appearance, apparently by contraction of the primordial membrane, either before or imme- 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 fructifieil 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. Early condition of pruthaUium of Gytnnogramma chrysophylla, about 20 diam. (Henfrey.) 80. The atitheridia. — The antheridia are situ- ate on the under surface of the prothallium, * Hofmeister, 1. c. pp. 78 — 82. 240 REPRODUCTION, VEGETABLE (Vegetable Ovum). 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 thesedivisions, and subjacent to the last-formed septa, are again divided b^' 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. Antheridia of Ptcris aquilina, 2G0 diam. On the right is seen an anthcridinm 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. 1 69. Archegonium of Asplenium septentrionah, 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 Equisetacese, Lycopodiaceae, and Rhizocar- pete. 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. 241 REPRODUCTION, VEGETABLE (Vegetarle Ovum). which the nuliment is composed. According to Mr. Henfrey*, on tlie 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- pilla-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 Hofineister’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 Hepaticae, 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- niuin, 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 |.rothallium. 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 Linmnan Society, vol. xxi. p, 135. Supp, described below in the rudimentary sporan- gium of Equisetum, into a central mass ol nucleated cells, with grumous contents (parent cells), enclosecl 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; asecond (endospore), which is distinguished by its greater delicacy, being subsequently formed within it.* 85. EquisetacecB. — 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; thesmaller,thecontents 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 a''e formed. 87. Antheridium. — The rudimentary' antheri- ditnn 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 chlorophy lie, 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 * Schaeht, Entwick. des Sporangiunis eiuiger Farnikraeiiter Bot. Zeitung, 1849. p. 537. f Ilofmeister, 1. c. pp. 97 — 103. ; Milde, Entwicke- Umgsgeschichte der Equiseten, &c. Bonn, 1853. R 242 REPRODUCTION, VEGETABLE (Vegetable Ovum). every respect, those of the Ferns. The anthe- riclia of the Etjnisetaceae are placed, not upon Fig. 170. co° Antheiidia of Fquisetum, 300 diam. a, ripe antheridimn, from which the antherozoids are beginning to escape ; b, unripe antheridium. (Hofuieister.) the inferior surface, hut along each margin of the principal branch of the prothallium 88. Archegoiiium. — The archegonia were first discovered and figured hy Milde* in Equisetuin Tehnateia, and have been since more completely described by Hofmeisterfand BischofFJ 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 hy 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 hy a quadrilateral intercellular passage. The whole is supported on a base, which consists of two or three rows of cells Fig. 171. Archegonium of Equisetum Telmatda, 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- schotf.) * Zur Entwick. der Equiseten. Bot. Zeitung, St. 32, 1852. t lieitrage zur Kenntnisse der Gefasskryptogamen (referred to hy Bischoft'in the following paper.). X Ann. des Sc. Nat. S. t. xix. p. 234. (Ex- tract from Bot. Zeitung, St. C. Feb. 1853.). 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 aiid 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 sjMrophpUa. 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. 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 Sclaginella (§ 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 I 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 gruinous 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, ntuch 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 j vesicle, on the surface of which the cellulose membrane of the future spore is secreted, .as |j well as the two parallel, elastic fibres by | which it is surrounded. When the spore is i ripe, these last, which are external to the ■243 REPRODUCTION, VEGETABLE (Vegetable Ovum). spore membrane, and consequently formed before it, line the inner surface of the parent Fig. 173. Developynent of parent cells of the spores of the same- a, one of tlie 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, whicli 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. LycopodiacecB.* — 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 prothalliuin 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 * Ilofmeister, I, c. pp. 118 — 124. are originally developed i/i 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,vvhich 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.j Fig. 17a. Archegonium of the same immediately after impregna- tion, GUO 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 2^4. REPRODUCTION, VEGETABLE (VEGETAnLE Ovum). 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 siispcnsor, penetrates the single layer of cells which separate it from the in- ferior surface of the [irothallium, and buries itself in the cushion-like mass. A new deve- lopment now commences in the terminal cell, which is divided by a succession ofse[)ta Inclined alternately in opposite directions, Fig. 1 7G, Eyg-shapad rudiment of embryo of the same attached to the suspensor, from the terminal celt of which it has originated, 300 dium. 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 developeil. Fig. 177. p a, prothallinra, continuous at its periphery with b, the original inner membrane of the spore; c, cellular body subjacent to prothallium, which ))rojects into the cavity of the spore; a, com- mencement of secondary axis of growth of the embryo ; below p are observed the remains of the arehegonium within which the embryo origi- nated. Several other unfructilied 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 spoi'angia 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- iliately above the middle of the line of in- sertion of the leaf, is develojred to a nipple- shapetl 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 hlartensi, which have taken their origin from a single macrospore, 5 diam. on a short |)edicle. 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 encloseil 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 disajjpear. 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 structui'e of which has been already described, are formed upon its surface. No sooner is this process completed than the membrane of the [jarent 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. 9.'}. In those sporangia in which microsporcs 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 ooplwridium, 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 membiane, and external three-valvcd tegument, but differ 245 V' V ! I 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. Valvate dehiscence of microspore of SelafineHa hcl- vetica, six months after sowing, showing escape of antherozoids, 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. Rkhocarpere. — In describing the mode of reproduction of the Rhizocarpeae, we shall confine our attention to the genus Pilularia, respecting which 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. 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 tlie same position a delicate cell of similar form, the upper surface of which is in contact with the endosporal membrane, and is immediately 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-celi. The lower, which is tabular, divides repeatedly by vertical sejtta, 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. 181. Section of macrospore of Pilularia some time after germhiution, 50 diam. a, two lay'ers of the exospore, the outer, vertically striated, the inner, homogeneous ; b, cavity of endospore bounded superiorly by' the prothallium, the papilloeform summit of which projects through the canal of the exospore. which is surrounded by a white coriaceouf= 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. Pertical section of prothallium of the same at the period of impregnation, which passes through the axial canal of the archegonium, and exposes a, tlie germ-cell; b, cavity of macrospore; h, 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 metitioned. 99. The embryo. — In consequence of the presumed entrance of theantherozoids 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 •246 REPRODUCTION, VEGETABLE (Vegetable Ovum). increases by tlie repeated division of a ter- minal cell by alternately inclined septa. The Fig. 182. The samcaflo' impregnation, 150 diam. The papilla has been broken oft’ in making the preparation. direction of growth of this structure, which is the fu st leaf of tlie embryo, is obliquely u[)- wards. In its axil is formed the [)rimary axis^ Fig. 183. Kmhrxjo of Pihdaria ghhulifera, 10 d’am. The embryo is sti/i enclosed in the proihallium, the tissue o f 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 macrospore. and soon after, as a lateral development from this last, the second leaf. In the meantime the firsfcroot makes its appearance as a roundeil jirojection, which grows from the upper sur- face of the embryo, in a direction opposite to that of the first leaf. Both of tlie last-men- tioned organs finally burst through the remains of tlie prothallium, and become free. 100. Sjtorangia and s])ore.s. — 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 sjiorangia 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 fluiti, 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 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- jiearing. 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 wdien it is subjected to the influence of moisture. 101. The microspores are developed precisely as in Selaginella. The exosporal membrane Ulicrospore of the same, GOO diam. The inner membrane projects tbrougb the outer, which has given way. A few of the cellules containing spennatozoitls have escaped. dehisces in three valves, the proper membrane of the spore at the same time giving way irre- gularly, to allow the escajie 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. Fhanerognmia. — 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 Coniferte the embryo is formed iqion a plan which presents the most striking analogies to what is observed among the Rhizocarpese and Lycopodiacese ; 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 intheprevioussection,weshall confine our attention to the Abietineas, 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 ami thick nucleus of delicate cellular tissue, which is enclosed in a single, somewhat fleshy integument, leaving open a wide micropyle canal.* In the centre * 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). 247 of the nucleus there exists an ovoiclal embrvo- 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 Finns Austriaca, in the centre of which is observed the young embryo- sac, 150 diam. mucus, the nucleus which it at first contained having disappeared. It corresponds, as will be seen as we proceed, to the internal mem- brane of the ripe macrospore of the Rhizocar- peae and Lycopodiacete. The pollen grain in theConifersegenerallyitself reaches thesummit 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 w’alls 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, and 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 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 microp3le end of the embryo- Fig. 186. Section of naked ovule of Finns maritima, as ob- served in January of the second year, 150 diam. The spherical embrj'o-sac is filled with cells, the walls of which are already thickened by gela- tinous deposition. Two polleir gi-ains occupy the funnel-shaped space between the wide micropjde 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 are Fig. 187. Four cells which surmount the corpusculum of Finns sylvestris, seen from above, 200 diam. * To this tissue is commonly applied the terra “ albuminous body.” It corresponds in its mode of origin with the “ endosperm ” (§ 106.) of other Phauerogamia. R 4 248 REPRODUCTION, VEGETABLE (Vegetable Ovum). separated from each other hy as many vertical septa, meeting at right angles. Each corpiis- cuhim is likewise surrounded on all sides by a single layer of cellules resembling pavement epithelium, and exhibits in its interior a nu- cleus winch is usually placed at its superior extremity. After some time the nucleus dis- a[)pears, and now a number of transparent vesicles become visible, which accumulate for the most part towards the extremities of the corpusculum. Fig. 188. C(irpiiscuhi?n of the same in section, immcdiatcl y be- fore impregnation, 200 diani. Its cavity is tilled w'itU 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 Ci’yptogainia. 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 iminediatelj' after is jrene- trated liy the narrowed end of the pollen tube, which is brought into immediate con- tact with the summit of the cor(nisculum, the four cells which previously surmounted it having disappeared. At this time, the corpus- ciduni exhibits in its interior, at the end oppo- site tlie 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. Corpjisculum 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 bod3^ a, 300 diam. Earlier stage of development of lower end of the same. A single germ-cell is applied to its wall. h, 300 diam. Division of germ-cell into four by two vertical septa, of which one only can be seen 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 Hofineister). 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 vvhichthe 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 the Hepaticae and of the first leaves of the Ferns and Equisetacem,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. Fhancrogamia 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, 24-9 REPRODUCTION, VEGETABLE (Vegetable Ovum). 106. Hippuris vulgaris* — The already ana- tropous ovule of this plant consists of a C3 lin~ drical nucleus of delicate cellular tissue, along one side of which is observed a longitudinal fleshy ridge, terminating above in a short funi- culus, bj' which the ovule is suspended from the a[)ex of the one-celled ovary. One of the central cells of this nucleus becomes larger Fig. 190. Section of naked nucleus of Hippuris vulgaris at an early stage, about taU diam. The embryo-sac is seen as a large central nucleateJ cell. (Unger.) than the rest, from which it is further distin- guished by its containing a free vesicular uu- 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 finall}' 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. into a tubular superior, and a spheroidal and much smaller inferior compartment. The Fig. 191. Upper end of emhryo-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 divideil by a vertical septum into two hemispheres. In these two new septa are formed, also vertical, but at right angles to Fig. 192. The same imniediatety after impregnation. I'he germ-cell is now divided b}' a transverse sep- tum into two compartments, the inferior of which is the parent-cell of the embr3'o. 250 diam. the last. In the meantime, several new vesicles 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 embr3'o now divide by hori- zontal septa, which are succeeded by others parallel to its surface, and meeting their pre- dece.ssors at angles of 45°. The globular body which is thus formed, comsists of six- 250 HEPRODUCTION, VEGETABLE (Vegetabi-h; Ovum). teen eells, of which eiglit are superficial, and the other eiglit enclosed as a central spheri- Fig. 193. Later stage. Divisimi 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 1 94. Isolated sl.vteen-celled embryo of the same, with its flamentous 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 Annals of Natural History : — “ The ovide springs from the placental surface as a single [uqjecting 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. Farly condition of ovule of Orchis mascnla. The embryo-sac is exposed in consequence of the absorption of tlie 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 [irocess 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 2.51 REPRODUCTION, VEGETABLE (Vegetablh Ovlai). which is not evident, but which seems ana- logous to the suspen.sor, presently to be mentioned, meanwhile decays away.”* 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 /), after passing the wide exostome becomes sensibly narrowed as it penetrates the canal leading to the embiyo-sac, with the out- side of which its termination is in contact. 180 diani. 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 after impregnation. The remains of the pollen tube are observed to be still adherent to the sac. The mdiment of the embiyo 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 Eeproduction of the higher Cryptogamia, and the Phanerogamia. Annals of Nat. Hist., June, 1852. By continuous cell multiplication an organ is formed, in which may be distinguished a Fig. 199, Further developed embryo. {Orchis Jflorio.') 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 loculi. 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, whicli 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 follow'ed in all of them by disappear- ance of the nucleus, and consequent division of the contents of the cell (primordial mem- brane) into tvvo 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 layers. The inner 252 REPRODUCTION, VEGETABLE (Vegetable Ovum). layer consists of radiating prismatic cells, and is soon absorbed. The cells of the second layer are distinginshed 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. Revieiv of the onalogies which present themselves in the history of the development of the reproductive organs of the higher Crijptogamiaand of the Phanerogamic!. — The families in question are distinguished by the presence of what is called “sexual reproduction” from aU others. It is true that among the Characete, Conju- gatae, Vaucheriaceae, and Desmidese, the con- currence of two dissimilar (larts is necessary for the develo[)inent 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 comjilicated as in the plants under our consideration. Taking the sexual germ as our starting [)oint, in com- paring the history of the development of the Ijhanerogamous with that of the cryptoganious ()lant, 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- firce are observed, early in the development, two vertical series of pa[)ill® — 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, vvith 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. f 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 * Nageli, Zur Entwick. des Pollens, &c. Zurich, 1842 ; Wimmel, Zur Entwick. des Pollens, &c. Pot. Zeit. 1850. S. 225. t Hofmeister, Entwick. der Zostera. Bot. Zeit. 1851 ; Griinland, 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 succes.sively com[)aring the de- scriptions contained in § 89 and (> 108. It is remlered still more striking when we consider the very remarkable variations wdiich 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 contenqilation 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 Equisetum 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, the pxollen cell, and the parent cell of four spores — In approaching this, the most difficult part of our inquiry, we must refer to the Coniferse, 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 ofa spore in each, is entirely wanting in the Coniferse. 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 conqdetely fills the central cell of the arche- gonium, while in the Coniferm, very numerous germ-cells swim in the central cel! 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. 1 14-. In the Hepaticse and Mosses one sep- tum is formed, the inferior of the two re.sult- ing cells undergoing no further development, while the superior is transfoi'med 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). ' 253 ever, examples frequently occur, in w'liich its develo]Hnent is changed, under the influence of peculiar external circumstances, in such a manner that, instead of producing a sporan- gium it lengthens considerabl}', 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 Equisetace®, 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 confei va-like fila- ment, vvhich lengthens downwards by repeated division of a terminal cell. At length the youngest cell is transformed into an embryo. Among the Coniferse, the same process pre- sents itself, with this im[)ortant 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. 115. The organ to which the name stispen- sor is applied by Mr. Henfrey in Orchis Morio, differs materially from that of Selaginella, the Coniferas, or from that described in the pre- ceding paragraph. Its formation does not, like that of the true suspensor, precede, but tollow's the origin of the emhryo. In Hippuris, it appears to result from endogenous cell-forma- tion in the lengthened upper compartment of the original germ-cell. 1 16. The difference between the development of the pollen grain, and that of the microspore of Selaginella and of the Rhizocarpeas, 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) betvveen the two fluids, the union of which seems to constitute the essential condition of fecundation. 1 17. 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 Ilepaticte and Mosses, Hofmeister observed within the involucre of Jungermannia bivancata,z.ni\\e\'o- zoa “ which moved rapidly and played livelily round the archegonia.”* In this species, as well as in J. bicrcnata and bicusjndata, the same observer found a mucous substance of glass-like transparency, occupying the months 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 ; w'hile in the contrary case, the archegonia are abortive. 119. Origin and development of germ~cells m special organs destined for their reception, which are capable of transformation into rudiments of new plants, iviihout the concurrence of two organs of opposite functions. — Of this, rlistinct ex- amples occur only among the Hepaticas ; viz. among the leafy' Jungermanniae, and the Marchantiffi. In one ofthe latter, the 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 backw'ards 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 |)lane of which inclines slightly backwards and downwards. The upper wall is formed by the double epi- dermal membrane ; the lower by a membrane which isintimately united with the parenchyma of the frond, in its relations to which it re- sembles the tissue which lines the suhepider- mal air cavities. It consists originally of a single layer of tessellar cells, much smaller than those tqion 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, Vergleichende Untersuchungen, &c. S. 38. Vide supra, Fiy. 1C4. 254' REPRODUCTION, VEGETABLE (Vegetable Ovum). to the axis of the froml. This is followed on each side by transverse, and afterwards by Fig. 200. Vertical section of Jloor of gem-pouch of Lunulai-ia, 50 diani. The club-shaped rudiments of the gems are attached by their bases to the superlicial 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 lorin 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 vertic.al septum, on each side of which the com- mencements of several transverse septa are mo- delled out in the protoplasma. 400 diam. b, the same at a later stage, 250 cbam. 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 fi ond. 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 tlie 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- face grow out into ni[)ple-shaped projections, which soon become filamentous roots,andthe whole is transformed intoa riband-shaped frond. The organ, the development of which is de- Fig. 2ns. Outline of gem as observed two or three days after it has been 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 tUrection of growth of the 3'oung 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.” Tlie 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) wdiich 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. a JO REPRODUCTION, VEGETABLE (Vegetable Ovuji). 255 256 REPRODUCTION, VEGETABLE (Vegetable Ovum). 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 mav be supposed to exist between plants and animals, they are to be sought be- tween the lowest members of the two series. Wlietlier we conclude that it is or is not |)0s- sible to mark out the limit which separates the one kingdom from the other, it is not to be overlooked tliat the plicnomena of reproduc- tion, and consequently the whole circle of the development, of the zoosporous Algae resem- ble more those which [iresent 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-sha[)ed 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, wbich is not contractile, encloses it, and now it undergoes a kind of cleavage, whicli 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 l aving been for a time endowed with ac- tive motion, and with a power of ingesting food, the Vorticella enters into a state of re- [)ose, 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 rejiose, becoming at the same time enclosed in a new membrane. What follows this change, however, has not been as yet ascertained. * Stein, Wiegmann’s Arcliiv. 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 paragraj)h, 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 fi'om 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 w'ith 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 ilescribed by Kdl- liker*, afterwards by Siebold j", anti finally by Cohn. J According to the last-mentioned author, two neighbouring individuals after ajtproacbing 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 Cohn, 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-hke 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 he 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 Alga; (Pahnoglcea macrococca), we shall contrast the circle of development, as it presents itself in Palmogloea and Proto- coccus on the one hand, with that of Vorti- cella on the other, as follows ; — * Das Sonnenthierchen. Zeitsclirift fiir Wiss. Zool. i. p. 198. t Ueber die Conjugation des Diplozoon para- doxum, u. s. w. loc. cit. iii. p. 62. 1851. J Beitriigo zur Entwick. der Infusorien, t. c. iv. p. 252. REPRODUCTION, VEGETABLE (Vegetable Ovum). 2.57 Zoosporous Unicellular Alga. Conjugating Unicellular Alga. Protozoon.* Production of a series of Production of a series of sterile Production of a series Zoospores. Podophryce,, Blonads, which are transformed into Vor- ticellai. Cessation of motion. Cessation of motion. Transformation’of VorticelliE into sexual Y\,ctinophries. Conjugation of two Podophryie. Conjugation followed by Cessation of grow'th. 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 repeatedlj^ without the intervention of any sexual stage. So long as this is the case the two developments correspond completely. Here it ma}' be observed that in the stage of cessation of grosvtb, which, in the Pro- tozoon, as well as in the Protophyton, follow.s 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 (Cercarise). 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 foi'ms, 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 Algm 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. f (./. Bunion Sanderson.') * Carus, “ System der Tliieriscben Morph.,” s. 329. t A. Schneider, “Bcitriige zur Entwick. der lu- Supp. Bibliography. — AlGyE. — Koldreuter, Das en- deckte Geheimniss der Cryptogamie. Carlsruhe, 1777. Hedu'ig, Theoria Generationis et Fructifica- tionis Plant. Crypt. Leipsic, 1798. Voucher, His- toire des Conferves d’Eau donee. Geneva, 1803. Kaulfuss, Die Keimnng der Characeen. Leipsic, 182.5. Unger, Die Pflanze im kloraente der Thier- werdung. Vienna, 1843. Milller (AT.), Entwick. der Chara, Bot. Zeit., 1845, p. 410. Rolfs, British Desmidiie. London, 1848. Kiitzing, Pliycologia generalis. Nordhausen, 1845. Fungi and Lichens. — Blalpighi, De Plantis quae in aliis vegetant. Op. omn. t. i. 48. Meyen, Pflanzen-Ph}-siologie, v. iii. Bleyer, Entwick. der Flechten. Gottingen, 1825. Wallroth, Natur- gesch. der Flechten. Franld'urt, 1825. Unger, Die Exantheme der Pflanzen. Vienna, 1838. Karher, De Gonidiis Lichenum. Berlin, 1839. Sc/miiVz, Bei- trSge zur Anatomie und Physiologie der Schwamnie. Lininea, 1843. IlEPATicji: AND Mosses. — Schmidcl, leones Plantariim, 1762. fiet/aiii?, Fundamenta Hist. Nat. Muse. Frond. Leipsic, 1782. JVees v. Esenheck, Naturgesch. der Europ. Lebermoose, 1838. Bi- schoff eewA Lindenherg, Nova Acta A. L. C., xvii. and xviii. Blolil, Anatom. Untersuch iiber Sphagnum, Sporangien der mit Gefassen versehenen Cryptog. Tubingen, 1837. Schimper, Recherches sur les Mousses. Strasbourg, 1848. Lanzius Beninga, De Evol. Sporidiorum. Gottingen, 1844. Fep.ns and EquisetacEyE. — Agardh, awi. Vou- cher, Mem. du Mus. dTlist. Nat. de Gendve, 1822- 23. Arra/fass, Das Wesen derFarnnkriiuter. Leip- sic, 1827. Mold, Moiqihol. Betrachtungen iiber die Crjqitog., Tubingen, 1837. Bischoff, Entwick. der Equisetaceen, Nova Acta A. L. C., xiv., 1828. Ncigcli, Anther, der Farnnkrauter, Zeit. f. w. Bot., i. 168. Zurich, 1844. Leszczyc Suminskt, Ent- wick. der Farnnkrauter. Berlin, 1848. Merldin, Prothal. der Farnnkrauter. St. Petersburg, 1850. RhIZOCAEPEyE yVND LA'COPODIyVCE.E. — Bischoff, in op. cit. N'dgeli, in op. cit., extr. in Ann. des Sc. Nat., ix. 99. Milde, Entwick. der Equiseten und Rhizocarpeen, Nova Acta A. L. C., 1852. PhanerogamIyA. — Camerarius, Dissertatio de re Botanica, 1676. 4to. Tubingas, 1717. Grew, Anat. of Vegetables, &c., 8vo. London, 1672. Blalpighi, Anatome Plantamm. Op. omnia, t. ii., fol. Lon- don, 1687. Limiceus, On the Sexes of Plants. Lon- don, 1786. Blorland ( Samuel), Observations on the Parts and Use of the Flow’er and Plant, Phil. Trans., 1703, p. 1477. Treviranus, Die Entwick. des Em- biyo. Berlin, 1815. Amici, Mem. della Soc. Ital., xix., pp. 253-257. Padua, 1823. Brown (Robt.), Bo- tanical Appendix to King’s Voyage. London, 1826. Fritsche, Devel. du Pollen, Me'm. de I’Acad. de St. Petersbourg, 1835. Schacht, Entwickelungsges- chichte des Pflanzen -Embiyo. Amsterdam, 1850. The reader is further referred to various researches contained in the 3rd Series of the Ann. des Sc. Nat. fusorien,” Muller’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. s RESPIRATION, ORGANS OF. 258 RESPIRATION.—ORGANS OF. I. Hu- man and MmnmaVmii. — The respiratory system of organs in man ami mammalia comprehends the larynx, the trachea, and the lungs ; embry- ologically, tlie thyroitl and thymus glands should he 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 (ttveu/iwv, Gr. ; Pulmo, Lat. ; Fonmon,Vt.', Lungen, Germ. ; Langs 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 ca|)acious 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 abiuulantly 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, 'flic pleura pidmonalis and p>^eura parietalis 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, rounil, 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 towmrds the mediastinum. That of the left is hollowed out to receive the heart. The root of each lung is attached to the 2>ostcrior 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 low'er 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 Maljiighi 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 f 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 tlie relations of the lungs to the thora.x and to the neighbouring viscera, .sec art. Tuon.rx. j- See Art. Larynx. J “Trachea, 3J" — 4i" longa, 8'" — ]2"' lata, et 0 pariete anteriore ad posteriorem, 1"' — 9"' anipla est.” — Disquisitiones de Stnretura et Textura Cana- liuin acriferuui. Scripsit Ernestus Schultze. Mi- tavi® et Lip-si.!!, 1860. 259 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 u|)per 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 tracheaistherefore 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 dfiected 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 fle.xible 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 laryn.x it is crossed by the isthmus of the tliyroid 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 pleurte, 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. 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. 2'he tracheal mucous membrane is a develop- ment of the pharyngeal. (Henle). It forms a Fig. 204. Fertical cutting through the epithelial and suh-epi- thelial layer of the trachea. ( A fter Kolliker.') 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 — 0’04"' 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 O-OOS."' The supei'ficial 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 o f 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 RESPIRATION, ORGANS OF, from 0'015 to 0'02"', and in breadth from 0'002o to O’OOF^', according to the measure- ments of Kdlliker.* Tliis order of ciliated cells is dis[)osed upon a bed of cytohlasts in a double stratum of about O’OOG to O'OF", 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 0'003 to 0-Q{H5'" in length ; and, further, each nucleus bears a very visible nucleolus (, c, b, c) ; and the elastic (a, a, a), longitudinally. During the ingress of the respiratory column of air into the lungs, both these orders of fibres must be stretched ; during the egress of the air, the one must actively contract, the other must passively recoil. This constitutes an expiratory force. It is important to re- member that these two elements continue to prevail in the parietes of the bronchi as long as they retain the character of bronchi pro- perly so called — in other words, to the limits everywhere which denote the origins of the intercellular passages. At this point the muscular element ceases altogether ; so also does the ciliated epithelium ; but the clastic * Med. Cbir. Tr.ans. vol. xxviii., 1845. s d 261 RESPIRATION, fibres proceed, under a modified form how- ever, over the walls of the intercellular pas- sages and air-cells. The muscular and fibrous structures are discoverable in the walls of the bronchi ‘after these latter have penetrated within the bounds of the lobuli ; but never the cartilaginous. This latter element, how- ever, exists in the walls of the smallest of the extra-lobular bronchi. The exti'eme enil of each bronchus is the common mouth of the infundibulum of Rossig- nol ; the peduncle of the pulmonary vesicles of Reisseissen ; the origin of the interlobular passages of Addison. The bronchi divide on no constant or regu/ar 'plan. — Small branches sometimes proceed from a large stem, at different angles, from every point of its circumference. Fig. 210. Diagram of portions of the hiunan lung imperfectly injected with 2va.r, exhibiting the mode in which the intercellular passages a, a, a, spring from the ultimate bronchi b, b. These are smooth-walkd) those alveolated. ( Original.') Frequently they multiply dichotomously (b. Jig. 210 ); 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 ireduncles; 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 |)oint of attachment of the bronchus is the ape.v (a) of the lobule (b) ; the o|)posite point being the base. The angle of tlivision in the bron- chial tree is, for the most part, the obtuse. ORGANS OF. This disposition of the tubes favours, mecha- nically, both the ingressing and the egressing column of air.* It has been maintained by Dr. Radcliffe Ilall'l', 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 tlie 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 regidated 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. \V. 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 pulinonary tissue. — Lobules. — Historical b'lbliograjdiy. — Fi'om 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 lungs 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 separede channels. If 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 phis vari^ qite la longueur de ces rameaux, le mode de ramification qii’ils subissent, le nombre de leurs subdivisions et la direction que celles-ci aft'ectent. On pent cependant les rapporter il deux types principaux : le iireniier comprend les tubes aO'iens qui soiit soumis au mode de division par ramifications alternes ; le second, ceux qui sub- issent la loi de dicliotomie ou de tricliotomie.” — Re- clierches sur la Structure intime du Pouraon de riloinme, &c. piar M. Rossignol. Bruxelles, 1846. f Trans, of Prov. Med. Assoc. 1850. J Carpenter, Principles of Human Physiology, p. 514. § Edinburgh Monthly Journal, May, 1851. II IMarcellus Malpighi, Opera omnia, Lugd. Ba- tav. 1687, p. 320. Lettre premiere. ^ “ Ex trachea in ipsas mox ex una in alteram patens sitaditus et tandem desinent in contiuentem inenibranum.” 2C5 RESPIRATION, ORGANS OF. fend the theory of Malpighi.* Willis f came next in the list of disputants. By him it was argued, that the extreme bronchi deprived of their cartilages bulged on all sides into the “ vesicles” described by Malpighi, and that they communicated among themselves. After Willis came BorelJ:, and Duverney. § By the former it was denied that muscular fibres exist in the walls of the vesicles ; by the latter it was maintained that the extremities of the bronchi in man’s lungs, as in that of the bird, communicated amongst themselves. Helvetius ( 1718) 11 now sought to modify the views of Malpigiii as developed by Bar- tholin and Duverney. He also admits that the pulmonary tissue consists of a cellular or spongy tissue, of which the cells open the one into the other. Haller H now entered the arena. This illustrious anatomist doubted the existence of a system of air-cells in the lungs, because he could not see that those of one lobide were connected with those of the adjacent. Haller, at this period, was followed by Hales, Volelfart, Hamberger, Hildebrand, each in his turn advocating some modification of the opinions already stated. A new epoch now occurred in the history of this controversy by the publication of the far-famed “Disseiialion” of Reisseissen.** In the judgment of the Berlin academicians the researches of Reisseissen overthrew, by un- deniable fact and experiment, the theories of Willis, Malpighi, and antiquity. It was taught by Reisseissen, that the air-cells form the real terminal extremities of the bronchial tubes, each vesicle being independent of the others, and having its own separate bronchial peduncle.f f In 1825, Magendle published opinions with reference to the structure of the lungs, which were essentially a reproduction of the views of Helvetius. The facts adduced by Magen- die did not, however, satisfactorily overthrow the theory of Reisseissen. In England, Home and Bauer attempted at this period to show that the pulmonary vesicles did not consist of dilated air-tubes, as supposed by Willis and Reisseissen, but of polygonal cells of deter- minate form. They declared a preference for the theory of Malpighi. M. Bazin, in the year B.artholin, De Pulmoiium Substantia et IMotu Diatribe. S. 1. p. 355 of the edition added to the works of Malpighi, Op. Om. &c. 1687. f Willis, Thomas, Opera omnia, “ De Respira- tione et Usu,” p. 8. Genev. 1G80. I Bore], De Motu Animautium, pars secunda. Haga;, Com. 174.3. § Memoire de I’Acade'mie des Sciences, 1718, quoted by Reisseissen, De Rulnionis Structura. Argent, 1803. Memoires de I’Acade'mie royale des Sciences, anne'e 1718, p. 22. tom. i. Elementa Phys. Corp. Ilumani. Laus. etBeni. 1761, t. 3. et p. 178. ** Op. cit. tt “ Extremi surculi cylindri sunt ut reliqui rami, sed brevissimi, nec sphrericas vesiculas nec poly- edras, nec cubicas referunt.” Lemons sur les Phe'nombnes Phj'siques de la Vie, ii. 37. §§ Phil. Trans. 1827. 1832*, reproduced the opinions of Reisseis- sen. In 1839, M. Sereboulletf followed on the same side. About this period, M. Bour- gery in France, and Dr. W. Addison in Eng- land, combated severally the views of Willis and Reisseissen. To the theories of these anatomists, more especial reference will be afterwards made. Dr. Addison J, from a re- petition of the method adopted by Reisseissen, concludes, “ that the bronchial tubes, after dividing into a multitude of minute branches, which take their course in the cellular inter- stices of the lobules, terminate in their in- terior in branched air-passages and freely communicating air-cells.” Mr. Rainey, whose excellent memoirs have rendered great service to the cause of the minute anatomy of the lungs, more clearly defines the distinction be- tween the inter-cellular passages (the lobular passages of Drs. Todd and Addison) and the true bronchi. § M. Hiischke || in 1814 pub- lished researches which tended to support the views of M. Bourgery. At this time Dr. Eichholtzl^ contributed to anatomy the re- sults of careful investigations into the structure of the lungs. The dissertation of Dr. Mole- schott ** was also added to the rich list of wmrks on the organisation of these parts. The views of this excellent writer differ in no essen- tial respects from those of M. Rossignolf f, who describes the extreme bronchi as termina- ting in hifimdibula, which sacculate into lateral and terminal alveoli (air-cells). In the year 1848, Adrius Adrian! J J published a dissertation of considerable value. It is illustrated by draw- ings taken from their own preparations by Schroeder van der Kolk and Harting. To this admirable essay, special allusions will be afterwards made. An inaugural dissertation, also, by Ernest Schultz devoted chiefly to questions of structural anatomy, now appeared to enrich the literature of this subject. The standard writings of the English ana- tomists issued at this period express chiefly the views of the continental authors above quoted. In Carpenter’s Principles of Human Physiology, and Messrs. Todd and Bowman’s Physiological Anatomyq excellent chapters * Comptes rendus cle I’Acade'mie des Sciences, la Structm-e intime du Pomnon. Paris, 1832. t Sereboullet, Auat. Comp, de I’Appareil Respir. Strasbourg, 1838. t Phil. Trans. 1842. § See his Memoirs “ On the Minute Stmcture of the Lungs,” 1845 ; “ On the Minute Anatomy of an Emphysematous Lung,” 1848 ; and “ On the Alinute Anatomy of the Lung of the Bird,” in vols. xxxii. and xxxiii. of Aledic. Chir. Trans. II Sommering’s Lehre von den Eingenweiden (etc.), p. 268. H In Alullen, Archiv, fur Anat. und Physiolofrie, Heft V. ** De Alalpighianis PulmonumVesiculis. Heid. 1845. ft Recherches sur la Structure intime du Pouraon de I’Homme et des principaux Alammiferes, &c. 1846, Bruxelle.s. Dissertatio Anatomica Inauguralis de .'ubtiliori Puulmenum Structura. Trajecta ad Khenum, 1848. §§ Disquisitiones de Structura ct Textura Cana- lium aeriferorum, &c. 1850, Alitavai ct Lypsiie. 266 RESPIRATION, ORGANS OF. will be found on the structure of the lungs. The works of the Wiirzburg Professor (Kblliker) contain the most recent, and jirobably the most conclusive and imj)ortant, researches upon this subject.* In the details which arc now to follow reference will be fre- quently matle to the views taught by this distinguished anatomist. Fig. 211. A yronp nfhhuhs loosened from their mutual attach- ments, indicating the mode in which each lolmle (b) receives a single bronchial tube (a). {Original.') Ate is represented the dichotomous manner in which the primary and secondaiy orders divide ; at e, d, and /, is shown the irregular arborescent method in which the terminal lobular bronchi project from every side and point of the circumference of the secondary bronchial tubes. ]\rtmile Anatomi/ of the Lobule. — The proper pulmonary tissue {h,Jig.2 \ 1.) begins where the bronchial tubes 21 l.),cnd. The latter are convective channels, and fulfd onlya mechanical purpose; theformeris the immediate seat of the respiratory process. These two parts differ no less in anatomical structure than in mecha- nical conformation. The bronchi terminate in the “ intralobular bronchial ramifications ” (Addison) ; “ lobular passages” (Todd) ; “in- tercellular’passages” (Hainey); “mouths of tlie infundibula” (Rossignol). These are different designations only for one and the same thing. The passages in which the bronchi end are greater in diameter than the bronchi themselves. Their sides are at first smooth (a), like those of the bronchial tubes ; they become afterwards loculated (c) with cells or alveoli, like the terminal air-cells (c, h) (ycsicidce s. cellules aerece s. Alalpighianes, alveoli pulmonum * Mikroscopisch-Anatomie, Sweiterbnnd, Lcipsic, ]850, and Handbuch der Gew'ebelchre des Men- scheu, YOU Kblliker, Leipsic, 1802. Rossignol. Lnftzellen oder Lungenbliischen of the German writers). Looking down along a section through one of these passages, it is perfectly easy to ilefinc either an “ infundibu- lum,” or a broad-based passage bounded by Malpighian cells. It is, however, ]ierfectly certain that Rossignol has given in his illus- trations far more regularity of outline to these Fig. 212. {After Harting.) a is the termination of a bronchial tube properly so called, ending abruptly in an intercellular pas- sage marked by its cellulated parietes. b, e, cell- tissue. parts than they present in the actual prepara- tion. The intercellular passages (Rainey), then, are those continuous channels in the lobule which are laterally sacculated by cells. They conduct the air to and from every part of the lohule. They give rise to secondary passages (b, e,Jig.20S.), wliich again lead to a third, &c., all communicating with a group of air-cells. Each of these passages with its appended system of cells, if bounded by an imaginarp outline, may certainly be called an “ infundibulum.” The intercellular passages unite and divide {a, fig. 210.). They thus inter- communicate. In this particular they are distinguished from the bronchial tubes (b, fig. 210.; c,fig. 212.), which never inosculate. The latter are merely convective passages ; the former are expressly organised for the office of respiration. The bronchi diminish in ca- libre as they divide; the intercellular passages rather enlarge in diameter (f fig. 213.). The former preserve in their branchings one main direction ; the latter run through the lobule at every angle. They are perforated at every point by secondary passages (a, e, fig. 212.) of vary- ing lengths and directions : sometimes only by a deeper cell than ordinary. M. Bourgery saw in this arrangement only a “ labyrinth of canals” (canau.r ramifies bronchigties.) Home and Bauer, mistaking the intercellular passages for the bronchi, remark, “ the cells of the human lungs are not dilatations of the bron- chial tubes, but are regular cells in which the 267 RESPIRATION, ORGANS OF. tubes terminate.” This really coincides with the supposition of Reisseissen : — “ trachea rainos ita per pulmones distribui, ut facta par- titione multiplici, singuli quique coecis nec ampliatis tenninentur finibus, quibus vesicute aeriferte constituantur.” Moleschott has slightly modified the views of Reisseissen : — “ jam singulos ductus aeriferos, non uti Fig. 213. the chief interlobular dimsionsnf the bronchi. The latter are observed to multiply both on the dicho- tomous and arborescent plan. (^Original.') c, c, denote the smallest of the tme bronchi which contrast by their smooth -walls the alveolated intercellular passages a, a, a. The latter exceed tlie extreme bronchnles slightly in diameter. Un- like these bronchnles (c), which never inosculate, the intercellular passages (a), ramify in every direc- tion and at every plane, and frequently open into one another, establishing thus a free communica- tion for the air between all parts of the lobule. b,b,b, indicate the ultimate air-cells of the lungs. They correspond in size udth the alveoli (them- selves true cells) on the walls of the intercellular passages, e, e, bottom of the sub -pleural or most superficial air-cells. Reisseissen voluit, coecis nec ampliatis finibus terminari dicit, verum ad latera parietalibus vesiculis instructos esse testator.” Kblliker adopts the views of Rossignol, and constructs an illustration which expresses more perfectly the views of the latter author. * If a series of hollow cells were disposed linearly, the points of contact being converted into foramina, as represented in this diagram, * “ Mit denselben stehen dann die letzen Ele- inente der Luftwege, die Luftzellen Oder Lungen they would accurately answer to the descrip- tion of the “ intercellular passages ” ('a', fig. 210.; 212.'). Itis,therefore, obvious that tw'o different minds, contemplating the same Fig. 2U. Diagram of two lobules a, a, of the human lung. (^After Kblliker.} b, b, b, h, ultimate air-cells ; c, c, the finest bron- chial tubes. (Magnified 25 diameters.) objects under two different preconceptions, would see in them “passages” or “ A lung injected with wax readily misleads to the Fig. 215. n (^After Rossignol.} h, extreme bronchial tube of the human lung terminating in the “infundibula;” a, a, infundibula multiplied into cells on their parietes. error committed by Reisseissen of supposing each cell to be the separate termination of a separate bronchial branch. Rut it is certain bliischen, in Yerbindung, doch nicht so, wie man friilier glaubte, dass jedes feinste Bronchialastchen terminal fn ein einziges Bliischen ausgeht, sondeni in dem dieselben immer mit einer ganzen Gnippe von Bliischen sich vereinen. Diese Blaschengrup- pen entsprechen den kleinsten Lappehen trau- benfbrmiger Driisen, und es ist daher nicht die geringste Nbthiguiig vorhanden, dieselben mit einem andern Naraeu zu bezeichnen, wie Rossignol der sie infundibula nennt, wenn auch zuzugeben ist, dass ihr Bau in manchen eigenthilmlich sich ver- halt. Wahrend namlich in andern Ilriisen die Driisenblaschen, -wenn sie auch nicht so isolirt fiir sich bestehen, wie man bisher angenommen hat, doch eine gewisse Selbstandigheit haben sind, die ihnen entsprechen Elemente in den Lungen, die Luftzellen, in bedeuten Grade untereinander ver- sehmolzen, so dass alle einem Lappehen angehbri- gen Blaschen nicht in Abzweigungen der zu dem- selben tretendeu feinsfen Bronchialastchen, sondeni in einem geraeinsamen Hohlraiun einmunden aus dem dann erst das Luftgefass sich entwickelt.” — Mic. Anat., Zweiten Hiilfe, p. 309. 2G8 RESPIRATION, ORGANS OF. that Reisseissen mistook the infundibula of Rossignol which are loculated with the ulti- mate cells, both terminally and laterally, for the separate ends of separate bronchial tubes. It is no less certain that Rossignol has disposed with unnatural ()recision the “cells” and “[)assages” of wliich the lobule is composed. Scludtz, again, has erred in viewing the in- tercellular passages in the light of “bronchial petioles;” — Rronchioloruin continuationes ita constructas causis supra dictis commotus ap- pellaverim |)ctiolos, atque hanc dcnominationem uovam commeiulo, fines autem eorum aniplifi- catos nomine jam antea ipsis indito infundibula voco ; cos denicjue alveolos, (jui in pctiolis reperiuntur alveolos parietales, omnes vcro, qui in inl'undibulis occurruut, alveolos termi- nales noniino.”* Professors Schroder Van der Kolk,IIarting, Promotor,and their pupil Adrius Adriaiii, adopt the opinions of Rossignol in i-clatiou to the dis[)osition of the air-cells and passages within the lobuli. Whether the intercellular passages be distinguished by that name or by that of the hifiindibida, it is certain that they differ both from bronchial tubes and from the ulti- mate air-cells by a greater diameter. The nearer they are to the poitU of their attach- ment to the bronchial tubes, the more tubular or cylindrical their figure or outline ; the fur- ther, the more irregular and inosculating, until Fig. 21G. A sertimi at riijht anyh to the axes of the “ infun- dibula” showing the alveoli (b, e). After Jiossiyiwl.') finally they terminate in air-cells ; not after the manner supposed by Reisseissen in form of a Florence flask ; for the extreme cell has the same diameter as the tube itself. From the accompanying diagram, constructed by the author, the relation between the bronchi, * Disq. (le Struc. et Text. Canal, acrif. Scripsit Ernest Schultz, Lypsia;, 1860, p. 34. intercellular passages, and air-cells will be readily understood. It is, then, important to remember that the intercellular passages are open spaces between the ultimate cells, their walls being constituted of these latter. Like the ultimate cells, there- fore, they participate active/^ in the process of respiration. They arc not merely convective conduits. Since they proceed at every plane and angle from the centre of the lobule, a section of the latter in any direction will cut these [)assages both trausvei'scly and longi- tudinally. Ultimate Air-Cells of the Lungs. — Vesicular, s. ccllulee dercce, s. Malpighimue, alveoli jnd- monum; liossignol. — An air-cell in the human and mammalian lung is a space circumscribed by a single wall of reticulated capillaries, and varying infinitely in figure, and presenting in different parts of the lung numerous vai ieties of size ; each cell having an opening embracing a section, more or less considerable, of its circumference. The cells on the walls of the intercellular passages (the sides of the in- fundibulum of Rossignol) may be defined as mere cup-shaped depressions, sometimes perforated at the bottom by a large foramen opening into one or more cells. Under the pleura the air-cell occurs as a four or six-sided chamber, of which the bottom, presenting under the pleural membrane, is rounded, and might readily be mistaken for the fundus of a pear- shaped vesicle, the apex rimuing into abronchial tubule. If a cell, situated in the central parts of a lobule, be selected for examination, it will be found as a polyhedral alveolus, one or two or more of whose sides are deficient or con- verted into a foramina, through which its enclosed space communicates with those of contiguous cells. No cell is a perfect geome- trical figure — such, that is, as would be formed by regular plane sides ; because ridges and partial partitions, from the encroachment of the angles of neighbouring cells, project into and multiply its interior. It is not often that the eye falls upon a unilocular cell having only one opening: they occur most frequently as ir- regular, angular spaces, with one or more im- perfect sides, 219. Those cells which com- municate directly with the bronchial tubes and intei'cellular passages open 'into them by large circular apertures ; and they are themselves similarly perforated, to communicate with other vesicles, which again open into others beyond them ; so that each of the openings in the air- passage leads to a scries of cells, 'extending from it to the surface of the lobule. The vesicles which communicate directly with the air-passages are more minute, and have a closer vascular network than those which lie nearer to the surface of the lobule ; an arrangement which is in beautiful harmony with the relative facility by which the air in them respectively is renovated. The dia- meter of the human air-cells is about twenty times greater than that of the cajjillarics which are distributed u|)on their parietes, varying, according to the ineasurement of 269 RESPIRATION, ORGANS OF. Weber, from the to the Jir of an inch. It has been calculated by M. Rochoux that Fig. 217. as many as 17,790 air-cells are grouped round each terminal bronchus ; and that their total number in the lungs amounts to no less than six millions. The dimensions of the air- cells given by M.Moleschot*,are verymuch less than those of Rainey and Kolliker. Accord- ing to the former observer, they range from Y^otli to T^ooth of an inch : those of Car- penter and Kolliker correspond with those of Weber already stated. They continue to increase in size from birth to old age, and present in man a greater capacity than in woman. Dr. W. Addison supposed that the air-cells did not exist before birth, that they were mechanically formed by the first act of inspiration, and that the foramina between the cells were really ruptured partitions caused by the pressure of the atmosphere. Fig. 218. Ultimnte pulmonary tissue from afceius three months old. (^After Hartmy, quoted by Adriani.') a, a, a, primitive “infundibula,” of which the parietes are as yet composed only of minute oval cells (c) ; ft, 6, ft, elastic tissue occupying the inter- vals between the infundibula, exhibiting the nuclei of its cells. * Op. cit. It was, however, first proved by Mr. Rainey, and by Professor Hurting more lately, that they exist nearly as perfect in contour before as after birth. Neither the form, the num- ber, nor the disposition of the air-passages and cells can any longer be held as the off- spring of chance, but as the nicely adjusted products of marvellous foresight and design. The preceding statement will enable the reader to understand the sources of the dif- ferences by which the views of different writers upon the structure of the lungs are marked. It is easy to make a“ labyrinth,” a “passage,” or a “group of vesicles,” or “a funnel-shaped ar- rangement of cells,” out of the complex ap- pearance which a section of an inflated and dried lung presents. It is important to observe that the classification of the cells into the pa- rietal and terminal, as suggested by Rossignol, is calculated to lead to a false idea as to the real arrangement of the air-cells within the lo- bule. The capsule of the lobule encloses a pear-shaped space ; but this is not the infun- dibulum of Rossignol. This ingenious author applies this term to those parts which Mr. Rainey and Dr. W. Addison have distin- guished as the air-passages surrounded and terminated by secondary passages and air- cells. The septa bearing alveoli which pro- ject everywhere into the funnel of Rossig- nol, render the word parietal, as applied to them, altogether unmeaning. Every recent observer admits that the air-cells open every- where into one another, such that the air entering one intercellular passage at one part of the lobule would traverse its entire extent through the intervening labyrinth of cells, and return through another air-passage into the same peduncular bronchus. When two sides of two contiguous air- passages or cells come into opposition, the resulting partition is not composed of two layers, but one. If the cells were formed by the protrusive force of the air in enter- ing in the first act of inspiration, such par- titions would, of mechanical necessity, consist of two layers ; they are, however, formed by an act of organisation. This curious and distinctive fact in the history of the human and the mammal lung will be again referred to. As the partitions of the cells are organised before birth, it follows that the geometrical outline of each cell must be determined before the first act of inspiration. The same argument applies to the foramina between the cells. They are not accidental perforations ; they are definitively and de- signedly organised orifices, and are sustained in a permanently patulous state by an arch- like arrangement of elastic fibres, which will be afterwards described. As the air-cells of the lungs of mammals generally bear no proportion in size to that of the body of the animal, so in the human subject there is no relation between the di- mensions of these cells and the stature of the body ; and it is probable that no estimate can be formed of the vital capacity of the lungs 270 RESPIRATION, ORGANS OR from a calculation of the individual dimensions of the air-cells. It should be observed that the orifices, by which one cell communicates with another, are of tlie same shape and dimensions as those which exist between the first set of cells and tlie broncliial tubes ; they can be very distinctly seen by looking down upon the air-cells from the intercellular passages, focus- sing the'microscope at the same time. Since these openings are not necessarily in a straight line, the exact number of cells which com- municate cannot in this manner be determined; but the number will depend upon the dis- tance which intervenes between any given part of the bronchial passage and the surface of the lobule : so that when a bronchial passage arrives nearest the surface it will be separated from it only by a single terminal cell. The dimensions of the cells in different animals present many diversities. In the lung of the kangaroo, especially in those parts remote from the surface, the air-cells are very small, and disposed with the greatest irregularity. The lining membrane is also proportionally imperfect, being perforated in many places opposite the areolae of the plex- uses, so as to admit the air passing through them to come into contact with the coats of the vessels, as in the lung of the bird. In this mammal the minuteness of the air-cell is such, that it is too small to contain a single ciliated epithelium {Rainey). In the lung of the rat and mouse the air-cells are still more minute, and certainly many of them are not of a sufficient size to receive even an indi- vidual particle of the dimensions of the bron- chial ciliated epithelium. The air-cells are disposed with the same kind of irregularity, and the pulmonary membrane is deficient, as in the lung of the kangaroo. In the lung of the hare, the air-cells are very small, but [lerhaps not so much so as in the preceding species. The lung of the rabbit resembles that of the hare, but its air-cells arc rather lai'ger. In the lung of the dog the air-cells are larger than in the rabbit ; but still in the more central parts of the lung they are very minute, too minute, indeed, to be capable of having a lining of ciliated epithelium without being wholly unfitted for the purposes of respiration. In the monkey, the air-cells are large, and resemble those in the human lung. In the lung of the sheep and ox they are, upon the whole, about the same size, and very minute in both.* The diameter of one of the intercellulai * As the following passage expresses the views of S. van der Kolk, Harting, Kolliker, as well as that of the writer, Adriaui, I append it here at length : — “ Has cavitates antea cellulas dictas, nunc Dr. Eossignol alveoles nunciipavit, quod admitti potest, si nemo tantum huic noinini regularitatem inathe- maticam adjungat, qua; in alveolario apium inve- nitnr; in pliiribus locis enim alveoli infundibulorum aut rotundi sunt, aut niagis poljgonam ligurani referunt; eorum parietes vasis cinguntur minutis- simis, confertissimis, saepe optime materia colorata impletis, et tune rete subtilissimum constituenti- bus. Fibrao autem elastica; potissimum ad mar- passages ranges from to of an inch, and that of the cells from to {Todd and Bowman). In the lung of the calf these cells do not exceed By Dr. W. Addi- son they are stated, in the human lung, to measure from to of an inch. Minute Structure of the Air- Cells. — Three anatomical elements enter into the composi- tion of the air-cells : the epithelium, the blood- plexus, and the elastic tissue. The inter- lobular tissue is not here considered. 1st. The Epithelium of the Air-Passages and Cells. — It was first surmised by Dr. Thomas Addison, from the phenomena of the dif- ference between pneumonia and bronchitis, that the air-cells of the lungs must be desti- tute of epithelium. Dr. W. Addison contends that the air-cells “possess an epithelium in form of large round nucleated scales, and from one to fifteen or more nuclei may be counted in a single scale. A great many nuclei without auy epithelial envelope may be seen upon them ; but I have never satisfied myself that they possess the ciliated cylinder epithelium so abundant in the trachea and bronchi.”* Mr. Rainey denies the presence of epithe- lium of any descrijdion on the interior of the air-cells, the vascular plexus being lined only by a “pulmonary membrane.” Rossignol is the only subsequent writer who has sup- ported this view; — “ Neither does the ciliated epithelium lining the bronchial tubes extend into the intercellular passages, and from thence into the air-cells, or rather air-spaces (speak- ing of the bird’s lung), but it ceases where the bronchial membrane terminates. In the mammal, but especially in man, in whom the air-cells are very large, the fact of their having 110 epithelial lining can only be proved by a careful examination of the parts with the microscope, and therefore, with no other means than those of deciding this question, it might always remain sub judice, so long as persons are found who are more ready to confide in the assertions of others than submit to the pains and difficulty of examining the point for themselves. Rossignol says : “ Les parois alv^olaires sont formees ; 1° par une charpente de fibres qui laissent entre elles des espaces vides ou areoles ; 2° par une mem- brane transparente, qui n’offi'e aucune trace de fibres, qui recouvre la charpente precedente, et remplit les cspaces vides.” In this passage M. Rossignol has evidently adopted without inquiry the conclusion of Mr. Rainey, with whose writings he seems well acquainted. The opinion of all German and English anatomists is now finally formed with reference to this gines septorum, quibus alveoli constituuntur, de- cummt, tamen uti jam monuimus, nonnullffi pei parietes ipsos etiani decurmnt. Vasa capillaria niajora hac tela sustinentur. In ipsis parietibus infundibulorum alveoli inveuiuntur, in ipsos brnn- chiolomm ramos sese ostendentes; Rossignol, qui etiara illos vidit, eos alveolos parietales vocavit ; nos autem, antequam ejus coramentatio fuerat edita, ccUutas parietales vocavimus.” — P. 43. Op. cit. * Phil. Trans. 1842, part i. p. 1G2. I Rainey, Med. Chir. Trans, vol. xxxii. 1849. RESPIRATION, ORGANS OF. 271 Fig. 2 1 9. Ullimate cells of the human lung, showing the trahi- cular framework formed hy the elastic fibres of the walls, and the hyaline pavement epithelimn which lines the interior of the air-cells, f After Schroeder Van der Kolk, quoted hy Adriani.) By this distinguished observer it is repre- sented under the character of transparent pavement epithelium, the cells of wliich are * In suggesting the Tvord hyaline as a distinctive epithet for this variety of epithelium, I do not wish to be understood as denying, in its component scales, the existence of every form of visible element. The word should be accepted in a com- parative sense, as signifying that their nuclei and granules are less declared than those of any other description of epithelium. t This figure is thus described by Adri.ani : — “ Alveoli constant membrana subtilissiraa structura cai'ente, quas autem membrana mucosa tegitur epi- thelio pavimentoso (plaat epithelium') admodum pel- lucido, in quo potissimum ope acidi acetici nuclei conspiciuntur ; propter singularem autem pelluci- ditatem sacpe difficile est, illud epithelium rite dis- tinguere ; vid. fig. 12. nostrum, ubi ad alveolorum parietes conspicitur. Cellulai conica; ciliatm qum in bronchiolis minutis adhuc conspiciuntur, in alveolis penitus deficiuut ; hsec membrana cum epithelio pavimentoso obtegit vasa sanguifera per alveolorum parietes ducta ; propter singularem tenuitatem im- bibitio atque absorptio per hanc membranulam facillime perflci posse facile intelligitur.” — Op. cit. p. 61. A thin secfhm of a few air-cells fy'om the human lung, viewed by transmitted light. {After Kolliker.) a, epithelium lining the air-cells; h, elastic tissue arching over and between the cells; c, the flat wall of a cell, showing the scanty distribution of elastic fibres over this part of the cell. By Kolliker the cells of this epithelium (a, 7%. 220.) are stated to consist of polygonal par» tides of from 1 — 1600th to 1 — 2250th of an inch in diameter, and from 1 — 2800th to I — .3800th of an inch in thickness. They repose imme- diately upon the fibrous layer. They are normally shed; though not readily detected in health, it is easy to discover these epithelia in disease. This epithelium lines every part of the air-passages and cells except the bronchi. These latter tubes are furnished with a thick layer of ciliated epithelium, w'hich, as formerly stated, terminates abruptly at the commence- ment of the intercellular passages. It may * The following passage in the Jlieroscopic Ana- tom}' of Kolliker refers to the figure cited in the text. “ Das Epithelium der Lungenblaschen ist kein flimerndes, wie man frliher ziemlich allge- meine amiahm, sondeni ein gervuhiiliches Pflaster- epithelium, das mit polygonalem Zellen von 0-005 — 0-007'" Durchmesser und 0-003 — O-OOT" Dicke in einfacher Lage immittelbar auf der Faserhaut der Luftblaschen aufsitzt. Die Zellen sind alle kern- haltig, und haben meist ausserdem der Trachea und der Bronchien anzunehmen, dagegen konnen allerdings mehr zufallig oiler dann in Krankheiten der Luftwege einzelne Elemente desselben dem Bronchialschleime sich beimengen. Beim Menscheii fallen diese Zellen ungemein leicht ah und liegen dan frei in den Luftbliisohen und feinsten Bronchien, doeh kann man fast in jeder Lunge, wenigstens in einzelnen Alveolen dieselben noch in situ sehen und bei eben getiidteten Thieren bietet bei Beobachtung der I.agorung derselben nicht die geringsten Schwie- rigkeiten dar.” — Op. cit., p. 315. point. Carpenter, Quain and Sharpey, Kirkes and Paget, Kolliker, S. Van der Kolk, Harting, Adrian!, and Schtdtz describe a 2}avemc7it e]f- thelium on the interior of the air-cells of the lungs; and the author who has devoted many special examinations to this particular point is now convinced that a fine pavement epiithe- lium does cover these parts which he proposes to distinguish as the ‘■‘hyaline ejnthelhim.'’ * Messrs. Todd and Bowman, like Rossignol, adopt the views of Mr. Rainey, and teach that the air-cells have no epithelium of any hind. The adjoined is the illustration of the epithelium given by Schroeder Van der Kolk in Adriani’s Essay. -j- furnished with a nucleus and minute granules They are adjusted accurately, as a single layer, edge to edge. The description given by K61- liker coincides with the preceding.* Fig. 220. 272 RESPIRATION, ORGANS OF. then be accepted as a fixed conclusion in tlie histology of the kings that the air-cells are lined internally by a single layer of hyaUne epithelium.” This conclusion is corroborated by the minute structure of the respiratory organs in (ill animals. In none are the vessels absolutely naked. Elastic Tissue of the Air-Cells. — The exist- ence of this tissue is admitted by every ana- tomist who has studied the subject. Its dis- position amid the air-cells is less known. It fulfils a part, though mechanical, of the high- est consequence to the movement of the lungs in respiration. The fibres of this tissue belong to the yellow variety. Tliey resist both the action of acetic acid and liquor potassae. They are most visible in the lungs of the ce- Fig. 221. {After S. Van (hr KolJt.') a, h, elastic ' tissue (with thick yellow fibres) bounding an air-cell in the lung of the wdiale; o, a small portion of the wall of the same, showing the capillary web injected. tacei. They are readily detected in those of all mammals. They are limited chiefly, in distribution, to the edges and margins of cells. They encircle foramina, and maintain them by their elasticity, in a patulous state. They not unfrequently arch over the roof of the air-cells, constituting to the latter true traheculce. They pass from cell to cell, and form an important connecting tissue. They are everywhere arranged in bands or fascicles, or in a large meshed net- work of single fibres, as shown in the adjoined figure. When they are distributed over the flat surface of an air-cell, they are situated im- mediately under the epithelium. As there are two ej)ithelial surfaces to each cell-wall, the intermediate vascular plexus being single, it follows that the elastic fibres must run over and between this plexus ou both of its sur- faces. A real framework is thus constructed which is well adapted to support the capil- lary layer ; and this is an important function, which devolves on the elastic tissue. The framework formed by this tissue over the w'alls of the air-cells is so large-meshed that it does not obstruct the contact between the air and the blood. These two elements are separated only by a slender hyaline lamina Fig. 222. View of a thin section of the lung of a Cat, viliich had been injected hy the pulmonary artery with gelatine, so as to fill blood-vessels and air-cells, and had been sliced when cold. {After Todd and Bowman.') a, a, a, air-cells and lobular passage in section ; l>, h, tbeir fibrous wall in section ; c, their wall in face ; d, extremely faint nucleus in the same ; e, e, capillaries ; h, nucleus in wall of capillary ; n, small pulmonary artery, or vein with simple wall. (Mag- nified 250 diameters.) of epithelium and the coats of the blood- vessels. At the edges, angles, margins of cells and the foramina between the latter, the fibres of this tissue are gathered into dense and strong bands having an arched and cir- cular disposition. It is suspected by Kolliker that there may be muscular fibre-cells among this tissue in the air-cells, like those already described in the walls of the bronchial tubes. But the long nuclei which occur in the walls of the air-cells, seen also by Mr. Rainey and frequently by the author, are situated in the substance of the tunics of capillary blood- vessels. They are neither so large nor so long as the unstriped muscle nucleus. In the walls of the bronchi the elastic fibres were described as denser and stronger than those of the walls of the air-cells, and as observing almost exclusively a longitudinal arrangement, the muscular fibres being dis- posed circularly. Among the air-cells they exhibit that order and [dan which fit them best to subserve the mechanical exigencies of the part. Harting, S. Van der Kolk, and Promotor have detected these fibres in the sputum of phthisis, which they regard as cha- racteristic of the existence of a vomica. A failure in the mechanical property (elasticitO of this tissue amid the air-cells is probably one of the conditions of emphysema. Vascular System of the Lungs. — The blood- system of the lungs constitutes a separate RESPIRATION. 273 system : “ the second, pulmonary, or small circulation.” The nutrition of some parts of these organs is sustained by another order of vessels, distinct from these. The pulmonary artery, conducting venous blood, and proceeding from the right ventricle, is the channel by which the blood destined to be arterialised is conveyed to the lungs. It is circumscribed in its distribution to the area of the true pulmonary tissue as distinguished from the bronchial. The plexus formed by its branches is emphatically the rete mirahile. The branches of the pulmonary artery follow those of the bronchi as far as the origin of the intercellular passages ; a point at which they assume an irregular course over and between the cells. A lobule of the lung receives, with great regularity, only a single ramusculus from the pulmonary artery. It is not so large in size as the bronchial tube w hich it accompanies. Within the lobule, the artery coincides with the tube in its divisions, which are here more intimately bound to- gether than at the extralobular stages of their course. It w'as supposed by Bourgery that the artery formed a framework of vessels around the tube. This is not the case. Of course, many of the branches of the pulmonary artery course between the lobules in oi'der to reach others more distantly situated. Reisseissen conceived that he had traced a ranuiscule of the pulmonary artery to the root of each “ vesicle,” describing a venule on the other side. Krause supposed that each individual cell, with unvarying constancy, had its artery and vein, and intermediate plexus.* Berres believed that each cellule presented, on its circumference, a great many facets, like the eyes of insects, each facet having its own plexus. Rossignolf embraces the views of Krause which assign a separate arteriole and venule to each cell. In the accompanying figure, taken from the essay of Adriani, and drawn from a preparation by Schroeder van der Kolk himself, the branches of the pulmo- nary artery are seen to run, not only between the ultimate air-cells, but in many instances through the very centre of the walls. With this view’ the exact description of Mr. Rainey coincides : — “ In the mammal the number of capillary plexuses is not, as some have supposed, the same as that of the air- cells ; that is to say, a terminal artery does not divide into a plexus at any particular part of a cell, its branches uniting for the com- mencement of a vein on the opposite part. On the contrary, one plexus passes between and supplies several cells. In the interior of the lung the exact extent of an individual plexus cannot be determined, in consequence of the removal of some itart of it by the sec- tion necessary for its exhibition. But, on the surface of the lung, where the extent of these plexuses, in relation to the cells over which they ramify, can be easily made out, an individual plexus may be seen to spread ‘^Huschke, Encycl. Anat. Splundmologie, Op. cit. p. 66. Siipp. over an area of ten or twelve cells in some parts and in fewer on others, the exact num- Fig. 223. A thill slice (near the pleural surface') of the lunq of the Cow, with the pulmonary artery (a), and pul- monary vein (c), injected. (After Schroeder Van der Kolk.) a, large arterial trunk terminating abraptly in small branches (b, h, h), which travel between and along the borders of the aii'-cells, and in the ulti- mate capillaries e, e, by short trunks as shown at d; f f foramina arising from the sections of in- tercellular passages ; g, llbrous trabecula?, supporting by their elasticity the cells, and preserving their wall at a regulated tension. her depending in some measure upon the size of the cells.” * Around the foramina and margins of the cells very frequent anastomosis takes place be- tween the minute branches of the jmlmonary artery. With reference to this artery, it should, however, be stated, that it difi'ers from all other arteries in the extremely infrequent inoscula- tions which occur between its secondary and tertiary branches — and that its blood mingles with that of no other vessel ; it is poured en- tire into the pidmonary veins. “ The trunk” of a vessel is most certainly very seldom seen ; * Op. cit. p. 7. T 274 RESPIRATION. on the flat expansion of a cell-wall. But it is quite an error to suppose that each cellule has its own separate arterial ramuscule. Professors Ilarting and S. Van der Kolk’s injections place tliis point beyond doubt : — “ quod ad divisionein rainoruni arteriaruin at- tinet, animadvertenduin est, non alveolnm queinque singidum rainulum accipere, quinn hoc tantuni valeat de infnndibulis, ita ut lobulus, infundibula continens, accipiat truncuin arte- riae, ille truncus ad numerum infundibnloruin ilividatur et itcruin subdividatur.” (Adriani). From this description it results that the ca- pillary web without an intervening trunk stretches from cell to cell. One more iin- Fig. 224. Injected preparation of a single arterial twig and Ilie attendant vein, showing a single plane o f capil- laries oiwrlging the air-cells. The pleural capil- lary system is distinguished from that of the true pulmonary tissue hy the greater denseness of the vascular web and greater mhmteness of the meshes in the latter situation. (^After Kotliher.') portant fact remains to be stated with refer- ence to the capillary plexus. It is nowhere doubled upon itself, as it is in the lung of the reptile. Every cell-wall and every partition between tbe cells bears only a single layer of vessels. The opposed sides of such a layer must therefore bound two dift’erent cells, and the current of blood by which it is traversed must be subjected on both its flat sides to the action of air contained in the cells. If this plexus were double, only one side could re- ceive the influence of the atmosphere. This type is exemplified in the reptilian lung. All other things being equal the respiration of the mammal and man must be twice in amount that of the reptile. But this anato- mical fact has also an interesting pathological bearing. When the capillary layer, or rather the blood borne by it, is the seat of disease, the products of that disease must be poured into the two contiguous cells, between which it is interposed, at the same time and in the same amount. This accounts for the rapidity with which pneumonic infiltration occurs. In the most injected preparation the diasneter of the capillary vessels of the rete mirabile exceeds that of the meshes. This, however, is not an exact expression of their propor- tions in the living state. The diameter of a single capillary, measured in the injected state on the wall of an air-cell, does not exceed TTiW (Todd and Bowman.) The human red blood corpuscle ranges, in the same drop of blood, from tjoVo to of an inch in dia- meter, the average being from to s-ioo- Then two red-corpuscles may traverse any single cai)illary abreast ? When allowance is maile for the difference between the internal and external diameters of the vessel, it will appear very probable that in man and mam- mals only a single row of red-corpuscles tra- verse the pulmonary capillaries at a time. In the lung of the reptile it is to be proved by observation of the living circulation, that a double row of corpuscles really does move along the vessels. This fact must reduce the amount of oxygenation which in a given time a single corpuscle receives. The pulmonary Veins convey the blood, arterialised in the plexus just described, to the left auricle. The distribution of the pul- monary veins differs strikingly from that of the artery and bronchia. Each lobule has its separate arterial aud bronchial branch. This regularity does not obtain with respect to the veins. The pulmonary veins arise in the form of minute radicles in the capillary plexus of the air-cells. Now although, as formerly stated, the individual air-cells are not furnished with a separate arteriole and venule, the extreme branches of the |julmonary artery and the in- cipient venules are separated in different parts of the lung by areas of similar dimensions. It follows, therefore, that the time during which a globule of blood in different parts of the lung is exposed to the agency of the air is equal.; in other words, every drop of blood which enters the lung is arterialised to the same amount from the equality of the areas of exposure over which it passes. It should also be observed that as the capillary web is spread over several cells, every particle of blood in transitu from artery to vein traverses the circumferences of several cells. This is a beautiful provision for securing certainty to a vital process. The minute venules unite to form visible trunks, which course irregularly over aiul between the cells and intercellular passages. They observe a general diagonal direction, the bronchia and artery occu[)ying with great constancy the geometrical axes of the lobide. They emerge out of this lobular space not at its apex, in company with the air-tube and artery, but at every or any point of its circumference. This is more obviously the case as regards the lobular veins along the" surface of the lung. Those more central!} si- tuateil follow the bronchia more closely. This|F explains why Reisseissen, Cruveilhier, and* others have expressed very opposite opinions iqion this point. In the intralobular siiaces the I RESPIRATION. 275 veins proceeding from several lobules unite together into a trunk coininou to them all. The larger trunks, resulting from the conflu- ence of the smaller, converge towards the roots of the lungs, but by a route different from that of the bronchia and arteries. Thus the general mass of the lung may be regarded as containing two series of ramified canals ; one transmitting the bronchial tubes, the nerves and pulmonary artery, the other the pulmo- nary veins. This interesting fact was well described by Dr. Addison of Guy’s Hospital in a paper in the Medico Chirurgical Trans- actions in 18-10. At the root of the lungs four pulmonary veins result, which discharge their blood into the left auricle. “ The cause of the separate course of the pulmonary arteries and veins is to be found in the opposite posi- tion of their radicles in regard to the capillary net-work of the lobules, it being a convenient arrangement for the terminal arterial and venous twigs to hold alternate positions among the capillary net-work, so that each arterial twig dispenses its blood in all direc- tions, and each venous radicle collects it from all sides.” * The Brcnchial System of Vessels consists of arteries and veins. The bronchial arteries are commonly described as the nutrient vessels of the bronchial tubes. They arise from the front of the descending or thoracic aorta. They are, however, variable in number as well as in place of origin. They are commonly described as the inferior and superior. The superior, two usually in number, arise either separately or by a common trunk from the front of the aorta, opposite the third or the fourth dorsal vertebra, and one directed to each side adheres to the posterior surface of the bronchial tube, on which it divides into branches, and passes into the interior of the lung. The inferior, two or more in number, arise lower down than the preceding, and are distri- buted, like them, on the bronchus of each lung : these small arteries giv'e branches to the oesophagus, bronchial glands and pericar- dium. The superior bronchial artery of the left side may arise from the superior inter- costal artery. Every successful injection ex- hibits large and long branches from these ves- sels, leaving the tracks of the bronchi, and entering into the inter-lobular tissue and sub-pleural tissue, f The bronchial Veins accompany the arteries, * Physio!. Anat. by Todd and Bowman, p. 393. vol. ii. t In an excellent paper recently read before the Roval Society (June 9tb, 18.53), Dr. Heale states this fact still more strongly. He denies that the vascu- lar plexus, distributed over the walls of the bron- chial tubes, is derived at all from this system of vessels, but from the pulmonary rete. I have re- peatedly remarked, that the bronchial plexus cannot be injected from the aorta. I ascribed the circum- stance always to some imperfection in the attempt. It will be seen in the text further on, however, that my injections prove the presence of a bronchial plexus on the exterior of the bronchial tubes, though not on the interior. and the branches unite one for each side ; the right opens into the azygos vein, and the left into the superior intercostal vein. Many branches may be traced also to the (esopha- geal veins, and those of the posterior medias- tinum. Numerous branches of these veins may be observed to wander under the pleura, in the sub-pleural tissue. Anastomoses between the Bronchial and Pul- monary Systems of Vessels. — Since the days of Ruysch, Haller, Soemmering, and Reisseissen, this has proved a vexed question in anatomy. One point in this controversy has been over- looked. The bronchial arteries are said to be the nutrient vessels, not of the lungs, but of the bronchi. The tissue composing the struc- ture of the air-cells and intercellular passages of the lungs is nourished by the blood of the ^ndmonary system. In the lungs of Reptiles there exists no bronchial system of vessels. The solid walls of these organs are occupied exclusively by the pulmonary system. It is upon the latter, therefore, that the function of nourishing the substance, the parenchyma, of these organs must devolve in these animals. Thus is proved the capacity of this blood. The epithelial particles and elastic fibres,; of the air-cells derive the materials of their nu- trition from the blood of the plexus (the true pulmonary) on which they immediately lie. It is indisputable, therefore, that the afferent blood of the lungs, like that of every other gland, discharges a twofold office, — that pro- per to the gland, and that of nourishing its tissue. Two systems or layers of capillary plexuses are discoverable on the w'alls of the broncliial tubes ; one lies immediately under- neath the mucous membrane, and exhibits ex- tended oblong meshes, which run parallel with the yellow elastic fibres ; the other lies on the outside of the circular muscular layer, so tliat the stratum of muscles is interposed be- tween the two systems of vessels. This outer layer of vessels, its trunks and capillaries, run circularly with the fibres of the muscles and at right angles with those of the submucous layer. The blood of the former empties itself into the pulmonary vessels ; that of the latter (the outer) returns by means of the bronchial veins. This, in brief, is the result of the au- thor’s investigations. They are confirmatory of those of Adriani. The itiode in which the bronchial and pulmonary vessels communicate is stated differently by different authors. Some suppose that the blood of the bronchial arte- ries is poured directly into the pulmonary artery, with the venous blood of which it admixes, and like which, traversing the respi- ratory plexus, becomes arterialised before it reaches the left auricle. On this supposition the blood entering the left auricle vvould be purely and exclusively arterial. By other ana- tomists— of these Rossigndl is the most pro- minent*— it is contended that the bronchia * “ Dans les injections faites paries artferes bron- clnqnes, le liquide reveiiait en abondance par les veines pulmonaires, en bien moinclre quantite par les veines bronchiques, et on n’en retrouvait aucune trace duns les raineaux de I’artere puhnonaire.” T 2 276 RESPIRATION. blood is poured into the pulmonary s^'stem at the left side of the respiratory retc. The cur- rent, therefore, entering the left auricle is not pure arterial blood : it is alloyed by the venous rivulet received from the bronchial system, — a reptilian characteristic traceable in human organisation. By a third class of observers it is said, that the capillaries of the pulmonary and those of the bronchial system of vessels intimately inosculate. The jjrecise solution of this question is difficult, in consequence of the readiness with wdiich an injection thrown into one vessel will pass into another by cxtrava- satiun. Other anatomists suppose that the three above-described modes of communica- tion actually exist. It is certain that these two systems du communicate, and that only a part of the blood of the bronchial arteries re- turns by the bronchial veins. More recently, a new aspect has been given to this controversy by the statements of Dr. Ileale, to the effect that the bronchial and the pulmonary systems of vessels do not in anp manner or degree communicate. He maintains, on the evidence afforded by his injections, that the vascular web of the air-cells extends, and is prolonged over the internal surfaces of the bronchial tubes. Dr. Heale assigns to this extension ef the retc mirahile the [lower of prolonging the aeration of the blood. This is impossible. The bronchial tubes, the minutest, are inter- nally lined liy a dense ciliated epithelium. Such e[)ithelium does not exist on the true capillarp parts of the lungs of any vertebrated animal. Where there is ciliated ejiithelium, a universal [irinciple of structure requires in the higher vertebrated animals that the function of breathing shouhl be suppressed. Tiiis prin- ciple, however, does not obtain in respiratory organs of the invertebrata, and in the bron- chial organs of lower vertebrata. liespiratorp Organs of Birds. The lungs of birds are two in number, symmetrically developed, flattened, and ir- regularly triangular in figure. They are fixed, by means of areolar tissue, to the ribs and vertebral column, from the inequalities of which they receive deep impressions. They extend from the second dorsal vertebra as far as the kidneys, and laterally to the junction of the vertebral with the sternal ribs. In their fixed position under the back and near the centre of gravity, they contrast strikingly with the lungs of mammals, which float loosely in the thoracic chamber. In colour they are blood-red, and in general texture they are more fragile than the lungs of mammals. They are not divideil by deep “ Par les artbres pulmonaires, I’injection revenait en entier par les veines correspondantes et jamais par les artferes broncliiques.” “ Enfln, rinjection poussM par les veines pulmo- naires remplissait tons les autres vaisseaux san- guins du poumon, c’est-li-dire, I’artbre pulinonaire, les artbres et les veines broncliiques.” — Kossignol, Op. cit. p. Gi. fissures into lobes, like the mammalian lung ; lobuii, however, exist, although more length- ened in form than those of the mammal lung. In the former, as in the latter, a Fig. 225. A. Lobide of the tung of a Bird represented in ideal longitudinal section. {Original.') a, a, a, primaiy bronchi maintaining a uni- formity ofdiameter and terminating coecally ; l>, b, b, secondary bronchi, maintaining also a regularity of diameter and opening into a dense cubic laby- rinth of blood-vessels c, c. B. A small piece of the ultunate portion of the lung, representing the arrangement of the ultimate re- spiratory capillaries. lobule is a smaller lung. All its parts are complete. The lobidi are embraced and isolated by membranes of areolar elastic tissue. A pleural investment embiaces their sternal aspects, and an aponeurosis, proceed- ing from the diaphragmatic muscles below, blends its fibres with those of this covering. The trachea, after a course in the neck vary- ing with the length of this part, at its entrance into the lungs, divides into two primary bronchi, one for each lung. At the place of this bifurcation there exists, in most birds, a complex mechanism of bones and cartilages, moved by appropriate muscles, and consti- tuting the true organ of voice. This part is known as the inferior larynx.* The trachoa is composed of rings of cartilage which are not deficient at the posteiior third of the circle, as in quadrupeds. The successive rings are linked together into a cylindrical form by means of a highly extensile and elastic membrane. The whole cylinder is embraced in a second concentric cylinder of muscular fibre which belongs to the voluntary or striped variety. In this particular it differs from the trachea of mammals. In the latter, only the deficient portion of the rings is cou)posed of * See arts. Larynx, Voice, and art. Aves. 277 RESPIRATION. muscular fibre, and that too of the involuntary or unstriped kind. This muscular layer in birds e.\tends from the superior larynx to the com- mencement of the bronchi : these latter are, however, unsiipplied by muscular fibres. They are exclusively membranous.* The bronchi in the case of birds, on entering the substance of the lungs, divide and subdivide without decreasing in diameter (a, a, a. Jig. 225.) Patches of cartilage appear in the parietcs only of the largest order of these tubes. They are distinguishable into two principal classes : those, first, which course superficially along the inferior or sternal surface, and which terminate by wide openings in the thoracic ami abdo- minal air-receptacles. This class of tubes is perforated by the inter-cellular passages only on one side, the other being strengthened by cartilaginous semi-rings. The deep bronchi, resembling cylindrical tubes, traverse the lungs in many directions, and freely commu- nicate with each other, not, however, to form a network, for they run in nearly pa- rallel directions. These tubes are always patulous on dissection, and seem incapable of contraction and dilatation. They are lined internally by a well-marked ciliated epi- thelium. The submucous tissue in the true bronchi is strong and dense, composed chiefly of elastic fibres, none of a muscular character. It constitutes a distinct fibrous layer, like that which lines the trachea of quadrupeds. Those bronchi which do not end in open orifices on the surface of the lung terminate coecally. These coecal extremities are perfectly defined by a prominent lining of fibrous and mucous membrane. It was first proved by Mr. Rainey that in the lungs of birds the mucous mem- brane does not extend inwards in the direc- tion of the interior of the lungs beyond the limits of the bronchi. By the words mucous membrane Mr. Rainey desires to indicate that flocculent covering which is so vvell seen in his injected preparations. By this observer it is maintained that all parts of the lungs of birds beyond the extremes of the bronchi are literally devoid of all epithelial covering whatever, the extreme capillary vessels being included in nothing but their own proper tunics. It has been already shown that Mr. Rainey has mistaken the cessation of the ciliated epithelium at the ends of the bronchi for the termination of all the other elements of this covering. The apparently naked vessels of the air-cdls are really in- vested by a hyaline epithelium, coinciding with that which, in the instance of reptiles, will afterwards be described. The abrupt termina- tion of the bronchial tubes marks the abrupt commencement of the intercellular passages. These passages contrast remarkably in struc- ture with the bronchi. The membranous walls of these parts are reduced to the ut- most state of thinness ; those of the former are furnished with cylindrical epithelium aud a dense fibrous coat. But, what is extra- ordinary, the dense mass of vessels which * See art. Ayes, by Prof. Owen. bound these passages are not joined together into a continuous partition. Each vessel is separate from and unconnected with those adjacent. “ A wall” thus constructed is at every point between the vessels permeable to air. These “intercellular passages” {b,b,L, Jig. 225.) arise, with singular uniformity, from the sides of the bronchi, at right angles to the axes of the latter. This is so constant as to become a characteristic point of structure in the bird’s lung. The “spaces” between the vessels forming the walls of the intercellular passages lead to no definitely bounded cells or chambers. They lead only to the interval which divides the contiguous bronchi from each other (c, c). This interval is filled densely with the ultimate pulmonary vessels. (B,7?g. 225.) It was first determined by Mr. Rainey that these vessels, in the bird’s lung, are arranged in a peculiar manner. They do not form plane reticular definitively bounded air- chambers. Each ultimate capillary crosses an air-space of its own. It is thus surrounded by air. The ultimate vessels interlace and interloop in every direction, forming a cubic mass of capillaries permeated everywhere by the air. The apparently naked loops of the ultimate vessels may be seen projecting into the areas of the intercellular passages. No- thing can be conceived more mechanically perfect than this arrangement of the vessels for the exposure of the blood to the opera- tion of the air. The latter is in immeiliate contact with each individual vessel (b. Jig. 226.) It surrounds the blood-current borne Fig. 226. Slightly oblique section through a bronchial tube. {Aftei- Bainey.) a, cavity of the tube ; b, its lining membrane, containing blood-vessels with large areola;; c, c, perforations in tins membrane, where it ceases at the orifices of the lobular passages (d, d); e, e, spaces between contiguous lobules, containing the terminal pulmonary arteries and veins supplying the ca- pillary plexus (f,f) to the meshes of which the air gains access by the lobular passages. by the latter. Every part of the circum- ference of this current, less than -g-gVo of an inch, is under the dii’ect agency of the aerat- T 3 278 RESPIRATION. ing element. In the bird’s lung there exist, therefore, no ciir-eells. It is argued by Mr. Rainey that the. nUimatt vessels in the bird’s lung, as in the inanmial’s, are literally nuked ; that is, that they have no other covering whatever than their own proper coats, of which at irregidar intervals the cell-nuclei may be distinguished. In other words, that the e[)itheliinn, so perce|/- tible on the bronchi, is 7wt under ant/ shape continued beyond the termination of these tubes. To this view it has already been objected that it is at variance with all ana- logy ; the branchial and pulmonary vessels of fishes and am[)hibia are provided, as will be subsequently shown, with pavement epithe- lium, the scales of which may be seen to be continuous with those of the ciliated divi- sion of the membrane; that a law of ana- tomical structure aiiplying to the resjnratory organs of the lower vertebrata must also govern that of the higher. It is impos- sible to demonstrate on the injected vessels of the bird’s lung the presence of a separate investment of epithelium. The vessels do appear to be literally naked. But in the recent structure, in their sections through the bronchi and intercellular passages, it is perfectly easy to the practised eye to trace the epithelium of the bronchi over the larger vessels amid the intercellular passages just before the former break into the mass of the ultimate eapillaries. The continuity of the pavement epithelium of the larger vessels with the cylindrical of the bronchi may be un- doubtedly traced by the eye. Now, what is true of the larger vessels is very probably true also of the smaller. Although, therefore, it cannot be directly proved at |)resent that in the bird’s lung the ultimate capillaries, as in the branchise of fishes and the saccular lungs of amphibia, arc invested by a separate epithelium, the conclusion first stated ap[)ears at present to be most reasonable and most in accordance with analogy. In these examina- tions it is important not to mistake the 02it- line of the red corpuscles in the vessels for that of the epithelial scales on their parietes. According to the measurements of Mr. Rainey the areolce between the ca[)illary vessels, which in the bird’s lung are the real air- spaces, — equivalent to air-cells, — are gene- rally smaller in diameter than the capillaries themselves, and average in diameter about MbVo of ‘O’ ioch. An epithelial eell taken from the lining membrane of the bronchi in a pigeon measures in length -g-i^,and in breadth •g-Tfoo- It is therefore certain that, as Mr. Rainey contends, ej)ithclium of such magni- tude coidd not, by physical possibility, line spaces the diameter of which did not exceed ■s-f’oo of ”” incli- The error here eommitted consists in overlooking the difference between the dimensions of the cylinder epithelium which lines the bronchi, and those of the won- drously attenuated hyaline epithelium which belongs to the true respiratory, capillary, areas of the lungs of birds, reptiles, and mammalia. A similar distinction between the epithelium which lines the csecal exti .mlties of glandular ducts, and that covering the merely convective or excretory stages of the same ilucts, obtains in nearly all the simple and compound glands of the animal body. How singular if a prin- ciple so wide-sj)read should be violated in the instance of the lungs! llcspiratory Organs of Reptiles. Temporary branchial of Amphibia. — In the life of ail batrachian reptiles, the period which immediately follows the emergenee of the young from the ovum is remarkable for the existence of organs capacitating the animal to live in water. In different genera these or- gans vary in duration of existence. The larvae of the frog retain the external hrancliiae only for a few days, after which these organs be- come internal. Those of the toad remain in the egg state for a longer, and in that of the fish condition fora shorter, time than those of the frog. The tadpoles of the terrestrial sala- manders of this country retain the external gills only for a brief interval, early assuming an exclusively atmospheric life. Those of the aquatic species, exemplified in the familiar tritons of our pools, carry the external bran- chiae for a much longer period, affording thus, an opportunity for the study of the structure Fig. 227. Head and hranctuat appendages of the larva of the Water-newt {TriUm aquaticus vulgaris'). (Orig.) Tlie branchise are enveloped in a prolongation of the general cuticle of the body. Tlie cells of the epithelium covering the gills are, however, reduced to a state of great attenuation, compressed into scales, and polygonal in outline. The nearer the period of transition from the larva to the perfect reptilian type, the more intimate the resemblance between the epithelium of the branchise and that of the general body. For some time before their obli- teration, the branchiar cease to be distinguished by ciliary vibration. This results from the change which gradually occurs in the anatomical characters of the component celts. The branchise in the larva of the newt consist of a trilobed extension of the cuticle at either side of the head, the two posterior lobes, ■which, in figure, resemble compressed finger- like processes, presenting on either side secondary projections, by rvhich the respiratory area is mul- tiplied. In relation to the size of the bod3’, they are larger than those of the larva of the frog. and function of these appendages. The ge- nera syren, proleiis, and mcnobranchus are RESPIRATION. 279 those only in which the external gills are per- sistent throughout the whole term of adult life. Whether temporary, as in the caduci- branchiate, or persistent, as in the perenni- branchiate genera, the branchial organs of amphibia are supported by no skeletal frame- work analogous to that which sustains the soft parts of the breathing apparatus of fishes. They are, essentially, only “ productions,” un- der a modified form, of cutaneous structures. Contemplated only as a mechanical contri- vance, whether provisional or permanent, up- on which devolves the most important func- tion in the animal economy, it demands a more minute investigation than it has hitherto received at the hands of anatomists. The cartilaginous arches erected on the hyoid bone do not entirely disappear until the internal gills have ceased to be distinguish- able. The circulating system of the decidual branchiae consists, in its earliest stage, of a simjile artery and vein ; that is, a loop of one vessel. As the larva grows these two vessels become separated by an intermediate system of capillaries. In the latter phase they offer no remote analogy to the vascular apparatus of the branchite of fishes. The cardiac centres are composed only of a right auricle and one undivided ventricle ; the left or pulmonary auricle remains unevolved until the organic necessities attendant on growth create a ne- cessity in the system for the exercise of the pulmonary functions. The left auricle is then superadded, and the chamber of the ventricle is partially divided by a median partition, and the embryonic organism reaches the maximum limit of development. The pulseless ventral artery, the resultant of the united afferent vessels of the branchiae, undergoes oblitera- tion through disuse. These general observa- tions form no irrelevant introduction to a more special examination of the branchial organs. Temporary external Gills. — The larval branchim of the frog and toad are less endur- ing and less complex than those of the sala- mandridte. From the earliest almost to the latest moment of their existence they are furnished with a ciliated epidermis. The gills are not specially ciliated The whole cutaneous surface in the larva of the frog and toad is similarly endowed. The cilia are in active play for some time before the larva emerges out of the egg : an admirable instance of foresight in the provisions of nature. The covering of the external gills of the ranidse is strictly cutaneous. In this situation, as every- where else, the epidermis betrays its real nature by the presence of pigmental cells. It is little less dense than the ordinary covering of the body. Nor does the vascularity of these tem- porary branchiae much exceed that of the rest of the cutaneous surface. These facts pro- claim their provisional character. At first they consist of a single minute lobe. This increases into two and then into several. They are cylindrical, not flattened, processes. They bear a single vessel returning upon itself. In this particular of ultimate structure they dif- fer from the branchiae of the salaraandridte. In these a capillary net-work is constructed between the artery and vein. This greater Fig. 228. One of the gills of the Newt viewed transpareyithj. ( Original.') a indicates the right auricle, which with i\ the ventricle, constitutes the heart of the true fish ; a' shows the left or pulmonary' auricle, which, being superadded to the two former parts, raises the car- diac organ to the reptilian standard, marked by' the presence of two auricles and one incompletely' par- titioned ventricle ; b, b'. denote the circuit of the branchial system in conformity' with the pisciform ty'pe. This system of vessels being obliterated during the metamorphosis of the larva, the pul- monary' vessels (c c') enlarge, the rudimentary' lungs at the same time expand, the associated auricle grows in muscularity' and dimensions, and the fish rises to the grade of an air-breathing reptile, d, is an enlarged view of the gill of the larva of the newt soon after its escape from the ovum. Secondary processes (d, d, d, d) are extended backwards, which materially multiply the surface. The whole gill is clothed with ciliated epithelium, the cells of which lose their cilia, and become non-vibratile for some time before the cessation of the branchial breathing, and the oblong-cilia-bearing cells (e) are transmuted into epidermal scales ( f) entirely' destitute of cilia. elaboration coincides w'ith their longer dura- tion. What is ephemeral in purpose is tem- porarily formed. This is nature’s workman- ship. They consist literally of small pro- longations of 'the skin, which is everywhere, as here, ciliated. At the moment of their fullest development, the larval branchite of the frog consist of four filamentary lobes. These are sessile upon the body or stem of the branchite ; they are somewhat granular on the surface, and slightly irregular in form. There is also frequently a short additional branch at the base of the posterior one. In these interesting organs the movement of the blood is readily demonstrated. It is a beauti- ful spectacle. It advances in a single current along one side and returns along the other. No sooner have these exquisite organs at- tained their greatest development than they begin to diminish in size. They become ob- tuse, and are gradually so reduced as to be withdrawn within the branchial cavity, and concealed by a little operculum of the integu- ment. The nature of this change of structure, which attends the transition of the branchim from the external to the internal condition, has never yet been defined by anatomists. It will be immediately describeil. The e.riernal Gills of the Salamandridee ex- ceed the former in size, in the number of the appended lobules and in the complexity of T 4 280 RESPIRATION. their vascular system {figs. 227, 228.) Like those of tlie I'anidae they are clothed in a vibratile epidermis, numerously starred by pigmental cells, in common witii the rest of the body. For some time before tlie deca- ilence of these organs in thelarvte of the triton they cease to exhibit the phenomenon of ciliary vibration. The vibratile epidermis undergoes a change by which the ciliatetl cell becomes succedeed by the simple. Idiis event foretells the ap|)roaching extinction of the parts. In their earliest conilition the branchiae of the newt discover only four minute simple cylindri- cal filaments. Each grows in length and thick- ness, and throws out from the inferior surface a double row of pectinated processes. These arc more complexly coustructcrl than the pri- mitive fdaments. They carry not only an afferent and efferent trunk, but an elaborate plexus of caitillary vessels. The pigment cells are limited in their distribution to the larger lobes, ami to the line of the larger vessels. The epidermis of the secondary processes of the branchice is reduced to extreme teniuty. Through it the eye readily tracks the move- ments of the individual blood corpuscles on the branchial capillaries. These elliptical bodies move like a boat, their long axes coinciding with that of the channel in which they arc travelling. Sometimes several proceed abreast. The diameter of the vessels of the teni[iorary branchite is greater than those of the lungs. In general terms it can be confidently stated that the quantity of blood circidating in the temporary branchim of the amphibia, at the period of their maximum development, is far less in relation to the amount contained in the whole body than that which the lungs, when fully formed, are capable of carrying. This inferior amount of blood is physiologically ex- pressive of an inferior functional power in the case of the temporary organs. Their respira- tory function is really only supplemental to that of the whole body. The whole cutaneous surface, as in the Nannatoid annelids, is richly ciliated. It is organised like the branchim. On these [larts, however, the epidermal layer is not so attenuated as that with which the branchite are invested. On these latter there is, however, a very perceptible e|)idermal co- vering. Its scales exhibit the ordinary hexa- gonal figure. This demonstration, which dispels all doubt, establishes the physiological principle, that the presence of epithelium is compatible with the respifatoiy office of the [lart which it clothes. This law prevails throughout the class of fishes ; it has also been reduced to actual fact by the author throughout the whole sub-kingdom of the invertehrata. But it must not be forgotten that its office on the breath- ing organs is almost exclusively mechanical. In no known example among vertebrated animals does the eiiithelial investment of a respiratory surface develop itself into any of the forms of a secreting organ. No “follicles” are, at any time or under any circumstances, discovered on these localities, in this class of animals, hut in the inver- tebrata follicular glandules are constant on the surfaces of the respiratory organs. The constituent scales are therefore function- ally passive. Nuclei and a granular proto- plasm would find no purpose to subserve if they were present in a highly developed form. Thus is exemplified the law of “demand” and “supply:” disuse entails attenuation on all living structures. Either the gases by which the epidermis of respiratory localities is traversed suppress the glandular office of the scales, or these latter, from the first, re- ceive a special organisation. The scales of the branchial epithelium contain nothing but a pellucid iluid. This fluid condenses, fluidi- fies, the respiratory gases in transitu. This is the office of the refined covering under study. The “[jrinciple” that the epithelium of the breathing organs is required by the physical conditions of its office to be reiluccd to the state of the utmost thinness receives new proofs from the study of the internal branchias. From all that is known it is probable that in minute structure the branchiae of the per- euni-branchiates conform to the plan of the temporary organs just described. The ge- neral arrangement of the primary branchial vessels and the structure of the heart are identical. rhe internal temporary Branchiae of the Amphibia. — The process by which these or- gans are witlulrawn into the interior of the l>ranchial chamber is not simply that of short- ening. It is the lahour of a new organisation. The internal gills of the tadpole differ in type Fig. 220. The internal branchia: of the Tadpole of the Frog. h, e, are the primaiy trunks supported by the cartilaginous arch c, which give olf the looped processes a; d, is one of the vascular loops vierved transparently, and showing the arrangement of vessels in them, and the epithelium by which they are covered. of structure from the external. The ultimate vessels of the latter are differently looped. 281 RESPIRATION. In both they are simple loops, but a distinc- tion is obv'ious ; so evident as to render it impossible that the transition from the ex- posed to tlie concealed state of the branchim can consist in a bodily retractation. On the external organs, preparatorily to their disap- pearance, the vibratile cilia first cease, the epidermis then increases in density, the meshes between the blood-capillaries enlarge, and the vessels become obliterated. These declining changes are not limited to the extreme distal ends of the branchial lobules. They occur simultaneously on every part of the surface. Temporary arches (c) of delicate cartilage now arise within the branchial chamber. It is from the convexities of these arches after the manner of the pisciform type that the neia vessels (a) of the internal temporary gills proceed. They are appended under the character of de- licate flocculi. Enlarged, they appear as minute digitations. Each carries a looped vessel, and is loosely invested with a de- licate membrane (d). This membrane belongs to the mucous, not to the epidermal, class ; and yet it differs in a striking manner from that which lines the rest of the branchial chamber. Nowhere is it ciliated. That co- vering the branchial vessels is remarkably thinner than the parietal portion. The former, however, is true epithelium. Its constituent scales are distinctly traceable by their out- lines, though they are as structureless as a basement membrane. It is not often that it happens that the epithelium of a breathing organ overlies, as in this instance, perfectly homogeneous parts. Nothing but the proper coats of the vessel lie underneath. Tliey are literally structureless and hyaline. The cells of the superficial epithelium, therefore, admit of indisputable definition. It is not “ base- ment membrane,” but e[)ithelium, though attenuated, that here invests the respiratory vessels. By this demonstration a principle is established. Epithelium is not supplanted by any other structure on the organs dedicated to respiration. No other instance, however, is known within the limits of the vertebrate kingdom in which this epithelium is ciliated, than that afforded in the case of the tem- porary external gills of the Amphibia. On those of fishes these motar organLsms do not exist. Wherefore this distinction ? Why should they exist on the external and not on the internal gills? It is not a law of the mucous membrane that they should not exist, for they occur in other tracts of this same structure. These are questions of ultimate design which it is not given to science to answer. Air-bladder of fishes. — This organ repre- sents the prototypal form of “ the lung” in the animal kingdom. It is present in nearly all osseous fishes. It is always tensely filled with gas. In that of marine fishes, ox3gen predominates ; in that of fresh water, nitrogen. Humboldt found the gas in the air-bladder of the electric g\mnotusto consist of 96 parts of nitrogen, and 4 of oxygen. Biot found 87 parts of oxygen, nitrogen, and carbonic acid in the deep Mediterranean fishes. No hydrogen has ever been detected in this organ. It occupies the roof of the abdomen, between the kidneys and chyloporetic viscera, and sometimes (gymnoliis ophiocephahes, coins), beneath the caudal vertebrae to nearly the end of the tail. In some species of diodon, tetradon, daciylopterus, pernelodus, and poia- notus, it is bifurcated. In arius gagora, poly- pterus and lepidosiren, it is divided lengthwise into two bladders. In the cyprinidee and characinidcB it is divided transversly into two communicating compartments. Man^- other varieties of forjii occur. (IfiV/c art. Pisces.) The proper walls of the air-bladder consist of a shining silvery fibrous tunic, the fibres being arranged for the most part transversely and circularly, and in two la\ ers. They are con- tractile and elastic. This coat yields the finest gelatine. Its fibres belong to the white variety: they “swell” under the action of acetic acid. A stratum of vessels is inter- posed between the mucous membrane aiul the fibrous layer. The meshes formed by these vessels are considerably larger and more oblong than those of the pulmonary capil- laries. In the latter instance the meshes exceed the vessels in diameter. The arteries of this organ are derived sometimes from the abdominal aorta, sometimes from the caeliac artery, sometimes from the last branchial vein ; and in thelepidosiren they are continued from the aortic termination of the two non-rami- fied branchial arteries, and therefore convey venous blood to the cellular, lung-like, double air-bladder (Owen). The veins of the air- bladder return, in some fishes, to the portal vein ; in some to the hepatic vein ; in some to the great cardinal vein ; and in the lepido- siren, they penetrate by a common trunk the great portal vein formed by the confluence of the visceral and vertebral veins of the trunk. In the jirotopherus and ganoid fishes the vessels of this organ form no retia mirabiita and vaso-ganglions, but rather a diffused capillary network, more close and rich in the anterior than the posterior part. In the osseous fishes, several varieties of the vascular system of this organ occur. That of the carp forms tufts of capillaries throughout the whole interior of the organ, a variety of which tufts occurs in the [like. The (lerch and cod exhibit a vaso-ganglion, a body pe- culiar to the air-bladder of fishes. In the coil-fish, a large artery, a branch of the coeliac, and a still larger vein, which empties itself into the mesenteric, jierforate together the fibrous tunic of the bladder. Before they reach the inner surface, they divide into some branches wdiich then radiate and sub- divide upon the mucous membrane. The arterioles frequently anastomose with each other. Both are inextricably interwoven, and form the basis of the so-called “ air-gland,” which is essentially a larger “bipolar rete mirabile” (Miiller), or vaso-ganglion. In the cod the ultimate vessels of this gland have a loop-like arrangement, their free surface [a a), being covered over with another layer of 282 RESPIRATION. vessels anil epithelium This organ, however, is further composed of a number of pecu- Fig. 230. Plan of hlnod-vesseh in the pJnnd (aih ogcnic?') nf the aif-hladder nf the Cnd-fsh, shnwing the simply hoped character of the vessels. ( Original.') II, a, indicate a stratum of fibres, vessels, and epithelium lining the internal surface of the gland in common with the whole interior of the air- bladder. liarly arranged, elongated corpuscles, which descend in two rows from each vascular branch, and are hound together by a loose cellular tissue : the corpuscles are beset with fine villiform processes. Thus it should be noticed that the veins as well as the arteries concur to form the vaso-ganglions. The vaso-ganglions of the eel and conger arc placed at the sides of the opening of the air-duct, are “ bipolar,” and consist of arteries and veins ; their efferent trunks do not ramify Fig. 231. Plan nf the blood-vessels in the glands of the air- bladder of the Eel. They consist of straight pa- rallel nliimatc vessels of uniform diameters, of arteries, and veins, carrying streams of blood moving in opposite directions. {Original.) in the immediate margin of the vaso-ganglion from which they issue, as in the vaso-gan- glion of the cod, turbot, acerino, and perch, but run for some distance before they again ramify to form the common capillary system of the lining membrane of the air-bladder. In the parasitic and suctorial dennopteri and pleuronectidae and ray -tribe the air-bladder does not exist. The ductus pneumaticus exists in the cel, sturgeon, amia, erythrinus, Icpidosfcus, lepido- siren, polyplerus. It is remarkable that in these fishes the vaso-ganglion is not deve- loped. “ Under all diversities of structure and function the homology of the swim- bladder with the lungs is clearly traceable ; and finallv, in those orders of fishes which lead more directly to the reptilia — as, for example, the salamandroid ganoidei anil tojjteri — those further modifications are super- induced by which it becomes also analogous in function to the lungs of the air-breathing amphibia.” * The Lungs in the Batrackia. — In the ichthioid amphibia there existtwo longmembranouspul- mouary sacs, extending, like the air-bladder of fishes, far backwards into the cavity of the abdomen, above the other viscera, but freely moveable in the cavity of the peritoneum, and invested with this serous membrane. They consist of smooth plane-walled saes, and communicate with the pharynx by means of their membranous ducti jmeumatici or tra- cheae. This simple condition of the lungs occurs in a permanent form in the salaman- dridae. Each sac is provided with a pulmo- nary artery, which runs in a straight course along the outer side of the organ. From this vessel, branches proceed with great regu- larity at right angles and at definite distances. From the midpoint of the space between the arterioles, a venule arises to run round the opposite semi-cylinder of the organ into the chief trunk of the pulmonary vein. In con- sequence of this regularity iu the distribution of the arteries and veins, the true capillary interspaces present a regularity of area. It follows from this arrangement that each drop of blood, in its passage from the extreme artery to the extreme vein, undergoes in every part of the lung the same quantum of aeration. It is commonly supposed, by com- parative anatomists, that the simple lungs of the satamandridee present a perfectly smooth and uniformly plane surface internally, such that every spot participates with equal acti- vity in the office of aerating the blood. This, however, is not the case. The septa which, in the case of the frogs and toads, divide the internal superficies into cells, exist in a rudi- mentary state, but unquestionably in the lung of the newt. They are indicated by inter- secting lines of vibratile cilia. They coincide chiefly with the principal branches of blood- vessels. Bundles of elastic fibres also run parallel with the vascular trunks, which confer upon these delicate organs an uncommon amount of elasticity. To the next point in the minute structure of the lungs especial * R. Owen, Cat. of Phj's. Ser. of Coll. Snr. 4to, 1832-40; MUller, .J., Yergleicliende Anatomie tier Blyxinoideii : Abhand. Akad der Wissenschaften zu Berlin, 1834 ; Agassiz, Hist, des Poissons Fos- siles, 1833-4.5 ; Cuvier et Valenciennes, Histoire Nat. des Poissons, 1845; De Blainville, Annales des Sciences Naturelles, 1837 ; Bojanus, Versuch einer Deutung der Kiioclien in Kopfe der Fisclie, in Oken’s Isis, 1818 ; Yarrell on British Fishes, 8vo, 1836; Paley, Nat. Theol. 8vo, ed. 10. 1805; Bre seller, Recherclies sur I’Organe de I’Ouie des Pois sons, 1838 ; Monro, The Stiaicture and Physiology of Fishes explained and compared with those of Man and other Animals, fob 1785 ; Scarpa, De Au- dita et Olfactu, 1789; Hunter, Ohs. on the Ani- mal Economy, I’alnier’s ed., 1837; Ratke, iu Die Pli3 siologie vmn Burdach, 8vo, i. 1826 ; Allen Thompson, Jameson’s Journal, 1830-31 ; Duvernoy, Sur le Me'eanisme de la Respiration dans les Pois- son,s, in Ann. des Sc. Nat. 1839 ; De la Roche, Ohs. sur la Vessie Aerienne des Poissons, Ann. du Mu- sc'uin, t. xiv. 1809. , RESPIRATION. 283 attention is invited. The conclusions here- after to be drawn will be found opposed to Fig. 232. A small pnrUnn o f the lung o f the Newt laid open and examined by transmitted light, under a high power, such that only the surface {internal or mucous^ is infocus. {Original.) a, a leading branch of the pulmonary artery, giving off at ver}' regular intervals which break at once into the true capillaries c, c, c. ; d, d, d, denote the parenchyraous islets which fill up the meshes of the capillary plexuses. (They are the true pul- monary parenchyma.) g, marks the abrupit line which abruptly limits the distribution of the ciliated epi- thelium, which follows the larger vessels in tracts; d, c, c, c, coinciding wuth the true respiratory or capillary areas of the limg, are seen to be destitute of ciliated epithelium. the views of Mr. Rainey. This excellent observer* has affirmed the principle that, on the true breathing portions, or capillary seg- ments of the lungs, there literally exists no epithelial lining of any description wliatever, the vessels being as literally naked. To this “ principle,” deliberately enunciated and sup- ported by elaborate “ proof” by an acute and truthful observer, many anatomists have yielded implicit assent. First, it is here objected that such a “principle” violates directly all the lessons of analogy. Analogy ! Is not demon- stration better than analogy? In the science of organised beings, the connected reasoning founded on analogy cannot be despised. The closest scrutiny in individual instances may miss the truth. The manifold illusions of the microscope may readily mislead. Analogy supposes a mass of cumulative evidence. The general law neutralises particular errors. In no instance whatever, either in the vertebrate or invertebrate kingdom, has it been proved, in the course of the present extended inquiry, that the vessels of a real breathing organ can exist under a perfectly “naked form.” What is true of invertebrate animals as an organic law cannot be untrue of the vertebrate. The • Med. Chir. Trans. 1848. gills of fishes are furnished ■with a very marked epithelial covering. The temporary branchiae of the amphibia are clothed -(vith epiderinis. The air-bladder is provided with an epithelial lining, the cells of which admit of ready and conclusive demonstration. Why should it not exist in the case of the true pulmonary striu'tures ? No reason can be imagined; but the fact that it does not has been affirmed by Mr. Rainey. Mr. Rainey’s observations were instituted upon injected preparations. This is the source of the error into which he has fallen. If the lung of the newt be carefully, but quickly, laid open, co- vered, hut not jtressed, with a thin slip of glass, and examined under the microscope, it will be found that the vibratile cilia have a limited distribution. Under the favourable o[)por- tunities afforded by such a preparation it is perfectly easy to follow with the eye the continuation oj' the ejnthelial cells (c, c, fg. 232.) beyond the limits of the ciliary areas into the true capillary or active breathing segments. The ciliated portions of the epi- thelium (over the vessels b, b) exhibit a flocculent character, precisely as shown in the preparations of Mr. Rainey ; while the areas immediately adjacent appear smooth or naked. But under the use of a higher power anti a steady gaze the polygonal outlines of the epi- thelial scales can be distinctly discerned most readily between the islets of parenchyma (rf, t/). If this covering consist of “basement mem- brane,” then basement membrane is composed of scaliform parts ; but it is not. It is a true and real and unbroken continuation of the tracheal and bronchial mucous membrane. It is only the ciliary appendages to the cells that cease at a certain limit ; the cells them- selves continue to invest the udiole super- ficies of the lungs. It is full of interest also to note that the epithelial scales which cover the capillary areas of the lung of the newt (parts which coincide with air-cells of the mammalian lung) lose not only the e.rternal apitendages (cilia), but also their internal parts (nucleus and granules). This succes- sive reduction leaves nothing but a hycdine involucrum enclosing a pellucid fluid. This is the real structure, supported indeed by a hypothetical basement membrane, by which the capillary areas of the pulmonary organs are invested. It finds a parallel in the trans- parent scales which cover the cornea. In these ribless amphibia the operation of breathing resolves itself into an act of “swal- lowing” air. The glottidean chink is em- braced by tw'O minute semilunar pieces of cartilages and furnished with muscles for opening and closing the orifice. In the pa- rietes of the lungs no trace of muscular fibres can be discovered ; but elastic fibres are present everywhere among the vessels. It is by the agency of this elastic tissue, aided by the abdominal parietes, that the act of expira- tion is performed. The exterior of the lung is lined by peritoneum, the scales of which are much attenuated compared with those of other parts of the s;une meir.brane, as those 28t RESPIRATION. of the internal lining. It is a curious fact that the exterior of the lung shoukl he desti- tute of cilia, while they should he |)resent on that of the liver in the newt. They are, how- ever, on this last organ, limited to the rnargiiio Notliingis more easy than to exhibit the living circulation in the lung of the newt. The which forms a thin pavement coating. This surface is destitute of cilia. In the frog, as in Fig. 234. A small piece cnincidinf/ with the true capillary nr respiratory area from the lung o f the Newt, viewed by transmitted light under a high power. The blood-corpuscles in streams are see7i in the spaces between the islets a, a, a. Only these parts are in focus. The hyaline epithelium covering the near .face of the picture is out of sight. The eye looks beyond it. In this fresh rinirijccted state the blood- channels' do not appear to be bounded by separate and independent parietes. (^Original.) a, a, a, are parencliyiiiatons islets occupying the meshes of the capillary rete. Tliey are composed of cells carrying nuclei and granules. internal bore of the vessel viewed by trans- mitted light is much greater than the long diameter of the red corpuscles. The meshes (a, o) are mere points. The scene is one thick, rich, surpassingly beautiful network of moving blood. In the frogs and tocid.s the lungs consist of two large, shoi t, and broael, slightly cancellated shining bags. They are situated on either side of the spine, at the roof of the abdominal cavity. They are remarkably elastic, like those of the newt. They are capable of slowly expelling their contents even after the removal of the abdominal walls, and of draw- ing themselves u[) into little hard balls on cither side of the pharynx. They exhibit well the living circulation. The glottirlean aperture communicates directly with the interior of the organ. There is, therefore, no trachea. The orifice of the glottis is surrounded by rudimentary cartilages somewhat further de- veloped. The mechanism of breathing is the same in the frog and toad, in which, like the newt, the thoracic ribs are wanting, as in the salamanders. The steps of the process are, however, better studied in the frog. The outer surface of the lung in the frog is closely invested with peritoneum, the epithelium of the newt, the edges of the liver are fringed with motile cilia. The pulmonary artery (see art. Circui.ation), derived from the aorta, pro- ceeds along the outer side of the lung. It lies immediately underneath the peritoneal epi- thelium. The very reverse course is taken by the large venous trunk on the opposite side. This lies in immediate contact with the internal or mucous surface. By this ar- rangement the contact of the blood with the air is prolonged. The contributory branches of the vein course along the free internal edges of the septa bounding the cells. The branches of the artery occupy the opposetl fxed borders of the same septa. The flat surfaces, or sides of the cells, being the areas dividing the arteries and veins, arc the scenes of the capillary segments. To this rule, of course, the eye, by close scrutiny, may detect many exceptions. By this distribution of parts, every spot of the internal superficies is functionally utilised. The ciliary epithelium is limited, in its distribution, to the margins of the cells and the lines of the larger vessels. The true capillaiy areas whereon alone respi- ration actively proceeds are covered only by a hyaline epithelium, the cells of which can only be distinguished by their outlines (yfg. 232. c,c). The ciliated tracts, according to the manner alread}' described in the lung of the newt, terminate by abrupt borders. The epi- thelial cell only is continued over the capillary areas. There prevails an avei'age uniformity in the dimensions of these areas. Each particle of blood, therefore, in its transit from the artery to the vein across this area, is exposed, for the same period of time, to the influence of the air. In the lung of the frog and toad the sc2tta support two layers of reticulate vessels. i RESPIRATION. 285 one on either side of a fibrous partition. A plane of vessels disposed in such a manner can only receive the influence of the aerating element on one side. This fact constitutes a real anatomical distinction between the lung of a reptile and that of a mammal. In this latter case the partitions of the cells are composed only of a single stratum, both sides of which are exposed to the air. By this simple mechanical provision the amount of the respiratory agency is everywhere doubled. In the structure of the reptilian lung the elastic fibre forms a predominant element. It is a substitute for ribs and other accessory apparatus of breathing. The lungs of the frog, relatively to the cubic capacity of their interior, present a much more extensive active surface than those of the Salaman- dridae. Thus the purpose of “the cells” is fulfilled, of multiplying the operative surfixce. The “septa” project from the sides into the interior of the organ. In this respect they may be likened to the gills of fishes ; for, like the latter, “ they penetrate the surround- ing medium.” The lungs of ophidian rep- tiles are generally composed of true unsym- metrical, long cylindrical or fusiform sacs, extending from the pharynx far into the cavity of the abdomen, above the other viscera, and surrounded with the serous lining of that cavity. They are capable of con- taining a considerable quantity of air, which, when driven out with force, produces the “ hiss” peculiar to the serpent. In some ge- nera, as the coluber, typhlops and vipera, the lung of one side onl}’ is developed ; in others, as the boa and python, the tw'o lungs are sym- metrically or equally developed. The lungs, in these families, communicate, by means of a long and narrow trachea, surrounded by incomplete cartilaginous “ rings,” with the back part of the tongue. In all ophidia, the lungs display internally, but owZy on the anterior and upper parts, an elaborate system of alveoli or cells, more like secondary lungs than air-cells. The posterior tw’o thirds of the internal superficies are almost plane, or devoid of “ cells,” like the lung of the newt. The alveoli, traced from before backwards, become shallower and shallower, until at length they disappear. It thus appears that the serpent may store up in its lung a con- siderable volume of air which, slowly passing out over the vascular air-cells, prevents the carbonic acid, the eflfete product of the pro- cess, from contaminating the whole contents of the organ. Each “ alveolus,” separately examined by vertical section, is found to communicate by a single opening with the general chamber of the lung. Traced inw'ards, it divides and subdivides into secondary and tertiary tiers of “alveoli,” each cell being isolated by dissepiments of which the struc- ture is identical with those of the frog’s lung already described. Each cell is a separate cavity. It does not communicate with those adjacent by openings in the septa. These septa are utilised in the outspreading of the vascular rete. Each septum, as in the frog. carries two layers of capillary blood-vessels, separated from each other and supported by an intermediate stratum of elastic tissue. In the mechanism of breathing, this tissue enacts an important office. Over the interior of the ophidian lung, like the batrachian, the ciliated epithelium is limitedly distributed. The true capillary areas which chiefly co- incide with the flat sides and bottoms of the cells are clothed only with ‘ hyaline epithelium.’ Everywhere throughout the interior of the lung, along the courses of the larger vessels, the bortlers of cells, or along lines of thick- ened tissue, the phenomenon of ciliary vibra- tion may be readily detected. It is thus evi- dent that the office of cilia is mechanical, if not to cause determinate currents in the air, at least in the halitus and fluid which, by accumulating, may obstruct the respiratory function of the capillary areas. In the boa and python the length of the left lung is generally less by a third or half than that of the opposite side ; but in coluber, crotalus and others, it is much smaller and auite rudimentary, appearing as little more than an obliterated appendage. The genera Ccccilia and Amphisbcena have the left pulmo- nary organ developed, and the right short- ened : this arrangement probably varies ac- cording to the species. Vipers and other serpents possess only a single lung, which on that account is very long. The lungs of the saurian reptiles conform in character to those of the ranidcB and salamandridce. They are elongated sacs, cellulated internally. They extend far back along the roof of the abdominal cavity. Like those of the ophi- dians, they are divisible into a cellulated and smooth or non-cellulated portion. The former is limited to the upiper and anterior half of the organ ; the latter to the inferior wall and posterior half. There may be a mechanical reason in this peculiar distribu- tion of parts. The cells in the lungs of the saurians exhibit none of the regularity so characteristic of those of the o[)hidians. They are larger and more irregular. The partitions of the cells are more slender and more de- licately membranous. The whole interior of the lungs in the higher saurians is multiplied into cells. An axis without definite walls, like a trachea, runs from one end of the organ to the other, as is the case in the lung of the turtle. From either side of this axis, large orifices lead to the more subdivided portions, or secondaiy and tertiary air-chambers. On the contrary, each lung in Scincus officinalis forms a single continuous cavity ; but the entire surface of the parietes is cellulated by small projecting reticulate septa. The internal dorsal and anterior half of the lung of the chameleon is, as usual in the sauria, minutely cellulated. Further back the cells become larger, and the septa smaller, until at the posterior part the walls consist onlj' of plane membrane both less vascular and less can- cellated than the anterior. The coecal ex- tremity of the organ is drawn out into an 2Sf) RESPIRATION appeiKlage-like process, which reaches the fartliest boundary along the roof of the abdo- minal cavity. These appendages may be aptly compared to the abdominal air-cells of birds which communicate with open ex- tremities of the bronchial tubes. The “ dia- phragm ” in the mammals precludes this interblending of the thoracic and abdominal organs, or the diffusion of air into any of the cavities of the body. With reference to the minute structure of the lungs in the saurians, it coincides pre- cisely with the account given of those of the ranidcc. Each septum consists of a central basis or framework of elastic fibrous tissue lined on either side by a reticulate layer of vessels. This [ilexus is again overspread by a “ hyaline pavement epithelium.” Rich tracts of ciliary e[)itheliinn may be discovered along the margins of cells, the course of vessels, aiul the lines of condensed structures. The double layer of vessels borne by each septum may be noted as a point of structure dis- tinctive of the reptilian lung. The lungs of the chelonian reptiles are very voluminous. They extend over the whole dorsal part of the trunk as far as the pelvis. They are fixed by the pleura to the ribs, which also separate them from the cavity containing tlie digestive and generative organs. They are symmetrically developed on the two sides. Tlirongh the centre of each lung longitudi- nally an Miiwalled axis extends from the an- terior to the posterior extremities. This is the main road for the air-currents. I’rom this axis, secondary jiassages, parietal ly cel- lulated, radiate towards every jioint of the circumferences of the organ. The ultimate cells are very capacious. They communicate little with each other. Each group has its common outlet, thus resembling a lobule, in the re[)tilian lung, however, there exist no lobules; an anatomical [larticular in which they are distinguished from that of all mam- malia. It is a criterion of lower organisation. The vibratile cilia which line the nasal and buccal passages, the pharynx and oesophagus, the larynx and trachea of all reptiles are most remarkable for tenacity of life in the lungs of the chelonia. In the trachea of the turtle, along certain tracts of the lungs, the motion of cilia may be detected several months after death. The [ihysiological value of the breathing process in any given animal cor- responds, not with the volume of air inspired per any unit of time, but with the measure of the blood-surface exposed to its agency, the rate at which the blooil-current moves, the numerical pro[)ortion of its red corpuscles,and the frequency of the respiratory movements. The small, but minutely, subdivided lung of the mamma! presents a much more extensive surface for the outspreading of the rete mira- hilc than the very voluminous, but spacions- chambered lung, of the chelonian. The total volume of air inhaled by the mammal is less than that which the lung of the turtle is capable of containing ; but in the former case it is more minutely distributed and divided ; it is more effectually employed ; the contact between it and the blood-web is far more extensive and intimate ; vdiile it acquires a higher temperature than in the latter. In these several particulars, cold differ from warm-blooded animals. Tlesplratorp Organs of Fishes. The aquatic type, distinctive almost univer- sally of the breathing organs of invertebrate animals, obtains also in the lowest order of the vertebrata. Fishes and the lower amphibia respire on the branchial plan. The difference between a gill and a lung rests more on ap- parent than real and ultimate grounds. In the last anatomical analysis this difference vanishes, and the eye is arrested only by the close structural affinities which reduce the two varieties to an essential unity of type. In both, the blood is exposed to the agency of the aerating element by means of reticulated ves- sels, furnished with distinct parities, and pre- senting a diameter little in excess of that of the corpuscles of the blood; so that these lattei’ must travel through the true respiratory capillary in a single series. This fact denotes the extreme measure to which the subdivision of the blood-stream is carried. It is a funda- mental requirement of the breathing organ, that all structures interposed between the blood and the surrouniling clement should be reduced to the utmost degree of attenuation. Accordingly, it is found that the epithelium overlying the rete mirahile consists of a single layer of attenuated scales, perfectly destitute of those contained parts which give bulk and density. In no instance whatever within the limits of the’vertebrata (excepting, as stated already, the branchice of the amphibia) are the true respiratory capillaries covered by a ciliated epithelium. This rule applies also to the branchiae even of the higher inverte- brata, such as the Crustacea atid ce[)halojjoda. The gill of the fish differs from that of the crustacean in the extreme minuteness with which the blood current is subdivided, and in the existence of specially parieted vessels ; conditions which denote an ' intensified measure in the function of breathing in the instance of the vertebrate animal. — In the blood of the vertebrata the floating cells are infinitely more numerous, relatively to the bulk of the fluid, than in that of the inverte- brata ; — a fact more expressive than the former of the greater activity of the respira- tory process in the vertebrate than in the in- vertebrate animal. It is an axiom in physics, that no gas is capable of passing through an organic septum without first assuming the fluid form. This axiom destroys the apparent difference be- tween a gill and a lung. In contact with the gill the aerating medium is already fluid: in the case of the lung, it takes this condition only in the act of passing through the partition dividing the blood from the external medium. Between the gill of the fish and the true lung ofthe ver- tebrate animal there is discernible, however, this differential character, that in the former RESPIRATION. 287 the epithelium clothing the active capillary segments forms a thicker layer |than in the latter. This is the only true and ultimate anatomical distinction between a gill and a lung. The preceding general facts will form an appropriate introduction to the study of special details, on which it is proposed now to enter. The Lancelet (Branchiostoma) occupies the first grade in the vertebrate series. It exhi- bits the branchial organs under the least com- plex terms. A capacious branchial sac, the dilated oesophagus, occupies the mid-portion of the body. It communicates with the ex- terior in front by means of a large oesophageal opening, and behind by a branchial outlet and a short intestinal canal. The parietes of the stomach display special provisions for breath- ing under the character of membranous du- plications of the internal surface. These folds are invested with a vibratile epithelium. In this particular the branchiae of this fish ap- proach those of the lower molluscs, and de- part from those of all other fishes. A con- venient aiTangement of this subject will consist in first studying the mucous membrane of the branchiae of fishes ; 2nd. the blood- system ; and 3rd. the supporting frame-work. Mucous membrane of the hranchuE. — The gills of fishes are lubricated and defended by aglary viscid secretion ; this is the product of the epithelium. This latter, therefore, even on these parts enacts a secernent office. On the plane superficies of the leaflets, the epi- thelium constitutes a single stratum, resting immediately on the expanse of the rete m'lra- bile. In this situation, as in all others, the epithelial layer is supported by a limitary mem- brane. From its extreme attenuation, how'- ever, it does not easily admit of separate defini- tion. Neither cytoblasts, granules, or any other immature particles, mingle with or underlie this layer of adult epithelium. It is difficult to conceive the mechanism of their renewal. In the interior of its component cells, how- ever, the eye clearly distinguishes a nucleus and a few pellucid granules. It has already been proved that these latter parts are almost suppressed in the epithelium which lines the active capillary segments of the true lung. Of the branchial epithelium of fishes it may be said that it unites the glandular to the me- chanical function of the pulmonary epithelium, that its office is exclusively mechanical. The kalitus of the air-cells is not a secreted pro- duct. It is a transpiration. Viewed with reference to the principles of exosmoses, a layer of amorphous granules, the cytoblasts of future epithelia, interposed between the blood-vessels and the super- ficial strata of adult cells, w'ould obviously render the partition to be traversed by the gases engaged in respiration very inconve- niently dense. The structure presented by the epithelium of the branchias implies, that in the organs ofaquatic respiration the blood is brought less directly into relation with the external medium than in those of atmospheric breathing. The cells investing the branchial capillaries are not structureless, hyaline, flattened scales, devoid of nucleus and granules, as though the principle aimed at were merely the me- chanical one of thinning to the extrdnest practicable limit all structures between the blood and the outer medium. They constitute irregularly oval bodies, carrying a nucleus, and provided with a few pellucid molecules. No cilia exist in the gills of fishes. In their fixed condition, as in the cyprinoid families, in their concealed situation, as in the shark tribe, or their exposed and free position, as exhibited in the higher osseous orders, — forms enough diversified, these organs are charac- terised alike by the complete and uniform absence of vibratile epithelium. The Vascular System of the Branchice. — In fishes, the w hole force of the heart and bulbous aorta is expended upon the branchial circula- tion. The power of the heart is materially reinforced by the resilient structure which composes the parietes of the aortic bulb. This structure is remarkably contractile. By all standard authorities on comparative ana- tomy the muscular nature of the walls of the bulbous aorta is admitted without question. The interior of this “ bulb” is strengthened by carnics columnce. It is a fact of no common interest that the colour of the muscular struc- ture of the ventricle is higher or redder in ground-fishes than in those species of which the habitat is superficial in the water, and which are gifted with the power of active locomotion. These facts are indicative respectively of supe- rior and inferior degrees of muscular irritability, and well shown to conspire with other proofs to determine a difference in amount between the respiration of deep and surface-sw’imming fishes. The valves which guard the proximal and distal portions of the hulbus arteriosus vary in situation, number and size, in different families. The movement of contraction which takes place in this vessel is not instantaneous in duration, like that of the ventricle : it is slow and vermicular. The pressure which is thus exerted upon the column of the blood is continuous. The near proximity of the delicate capillary structures of the branchiae to these powerful centres of force, demands the graduated manner in which the aorta re- acts upon the stream of the blood. This mode of action also explains the purposes subserved by the “ valves,” which in some instances occupy an advanced situation in the vessel. The abdominal aorta, which results from the confluence of the branchial veins, differs con- siderably in structure from the pre-branchial division of the vessel : the parietes of the former resemble those of a vein. Ko pulsa- tions are detectible in the abdominal aorta of fishes. The pulsatile movement of the blood, derived from the systole of the ventricle, ceases at the branchial capillaries. In fish, therefore, arterial pulsations exist in no other part of the circulating system than in that limited segment which intervenes between the branchial network and the cardiac ven- tricle. Neither the head nor any other jiart 2S8 RESPIRATION. of tlie body receives blood directli/ from the cardiac ventricle. The carotids, the homo- logiies of tlie subclavian, the hyo-opcrcnlar and orbito- nasal arteries proceed from the abdominal aorta at the point of confluence of the branchial veins. In these vessels, there- fore, the blood is arterialised, while its move- ment is impulsatile or venous. The pro- pulsive agents, under the form of diminutive lym|)hatic hearts, which Dr. M. Hall*, M. Fohinanf, and .1. iNIiillerJ have shown to guard the several points of communication between the absorbent and venous .systems, probably renders as great assistance in cir- culating the contents of the latter as those of the foianer orders of vessels. In the white- bait {Chipea alba of Yarrell) these micro- scopic hearts can be most perfectly observed. From a consideration of tlie preceding traits distinctive of the circulation of fishes, it will be afterwards shown that the laws of aquatic respiration are destined to receive new eluci- dation. Miuufe Circnialion of l/ie Branclno'. — The branchial arteries proceed on cither side, symmetrica'ly, from the aorta, and travel through a groove along the convex border of the branchial arches, the veins lying to the outside of the artery, that is, next to the [lec- tinated fringes of the gills. The cartilage system of the arches and that of the penknife- shaped processes (bearing the ultimate bron- chial leaflets) are quite distinct and uncon- nected save liy fibrous structure. It is in the in- tervals between these .solid parts that the trunks of the vessels are disposed. As the pectinated jirocesses (a, fig. 235.) arise, when biserial, alternately from the arcli, the ai terial branches leading to them observe a similar arrange- ment. The arteries carrying venous blood invariably run along the thick border or outer margin of each [irocess, the vein occiqiying the innermost edge. A branchial process, attached at right angles to the convex border of the arch, resembles a |)enknife, the back of which corres|)onds with the thick and outermost borders, and the edge of the blade with the thin or acute side of the process. A string carried from base to point would mark the position of the branchial artery convey- ing venous blood ; brought back along the acute eilge, it would denote the line of the branchial vein bearing arterial blood. In the mai'supio-branchii (as the myxine, 1am- jirey', &c.), in which the gills are fixed and inopercidate, this is also the virtual arrange- ment of the secondary trunks. In the lopho- branebii (sea-horse, pipe-fish, cStc.), in which the branchiae are tufted, the disposition of the minute vessels is not dissimilar. The flat surfaces of the penknife-shaped process are gorgeously festooned by foliaceous multi- plications of the membrane (Jig. 235, b). In the annexed illustration, one of these leaflets has been shown. In length it does not coincide * Essay on the Circulation of the Blood. t Sangader system der VVirbelthiere. 1827. j Elements of Bhysiology, by Dr. Baly, 2nd ed. Loud. 1839. with the width of the process; the secondary trunks, passing through the substance of the Fig. 235. A. Two lamella; or 2>enltmfe-sliaped processes of the hranrldal arch (f the Cod-flsh. (Original.) h, the vascular respiratory' plicie, which extend only three-fourths across the flat surface of the l>rocess. They' are seated on the internal longi- tudinal half or edge of the penknife-shaped process. cartilage (b) at right angles with the primary (a) are longer than the corresponding se- condary veins on the opposite side of the bladelet ; hence the one-sided position of the Fig. 236. Bepresents a transverse section of one o f the penhnife- shaped 2>rocesses (with a single leaf bearing the vltimate reS2hrillaries on each side) ; the web of vessels forms a single layer, and is covered by a pavement epithelium. ( Original.) c denotes the elastic chord which runs along the circumferential border of the leaflet. leaflet (c) bearing the capillarti networlc. These membranous processes, by which the active breathing surface is so extensively’ multiplied, if.. 289 RESPIRATION. are placed, like the leaves of a book, in close apposition with each other, the unattached sides floating freely in the water, the current of which, as it traverses the branchial pas- sages, bearing directly on the flat surfaces or the leaflets, separates them effectually from each other. Viewed edgewise, as represented in the following sketch, the arrangement of these respiratory membranous extensions may be moi e fully understood. On the branchial processes of the eel these leaflets amount to 700 in number ; on those of the turbot, to 900 ; on those of the cod, to 1000; on those of the salmon, to MOO. Especial attention is invited to fg. 2.37. It shows that the mucous membrane (t. e. the layer ot epithelium and basement membrane) is doubled upon itself, so as to assume the form of folds, the stratum of capillary blood being single. From this beautiful arrange- ment it results that the blood, in its [lassage through the labyrinth of this plexus, must present two sides of an extremely divided stream to the agency of the circumfluent medium. If the network of vessels were duplicated upon a supporting basis, only one side of the sheet of blood could re- ceive the influence of the surrounding me- dium. Regarded mechanically, such a plan would present little of the delicacy and |)er- fection which really distinguishes this most elaborate specimen of organised structure. This single-l'Ayer disposition of the respiratory vessels, doubling thus the surface of exposure, obtains as the universally prevailing type of .structure in the breathing organs of aquatic animals. It is an arrangement which faci- litates in a very remarkable manner the inter- change of gases between the blood and the water. The capillary vessels of the branchite of fishes, in internal diameter, exceed very little the long axis of the blood-corpuscle. The internal calibre of these channels varies from to yig of an inch ; the blood-cor- puscle in the cod measure in the long dia- meter ysVt inch, and the channels forming the capillary network present in all [larts precisely the same calibre. Cartilage, or Supporting System of the Branckiee. — The skeletons of fishes are struc- turally distinguishable into three classes ; the osseous, fibro-cartilaginous, and true car- tilaginous. In the conventional language of comparative anatomists the last is described as the least com[)letely organised, and the first the most. This distinction, however, which obtains in the adopted nomenclature of science, has no counterpart in that portion of the skeleton which sustains the foliage of the branchiae. In the petroniyzon Jluvudis the wicker-work of cartilage which Miiller has called the cartilaginous basket of the branchise, and which Prof. Owen regards as homologous with the cpibranchial system of osseous fishes, detaches processes of almost membranous tenuity stretching inwards to supply a mechanical support to the slender respiratory foliage. In the myxinoid families, Cartilage and calcigerous structures are sub- stituted, in various parts of the body, by elastic fibres. In the osseous fishes the Fig. 237. Skeletal f raniework of the lamellcE of the gills in Fishes ( Original.') a, section of the branchial ai-cli, which, in osseous fishes, consists of well-marked bone, and in the car- tilaginous, of soft cartilage ; b, marks the junction between the system of the arch and that of the lamellre, proving that the latter is quite distinct from the former; c, illustrates that portion of the framework which occupies the obtuse border of the lamella, exhibiting its external thick marginal fluted channel destined to convey the branchial artery from the base to the apex of the lamellai d, denotes that part of the skeletal fabric which coincides in situation with the acute margin of the lamella ; e, marks the situation of the branchial vein, as it emerges from the innermost aspect of the axis supporting the lateral processes f, which, by tiieir elasticit}', keep open or stretched the true mem- branous respiratory leaflets. branchial skeleton presents itself under the most readily distinguishable characters. From this class, accordingly, the following illustrative details will be drawn. The respiratory segment of the skeleton com- prises the hyoid system and its dependen- cies, in which are included the branchio- stegal rays ami the branchial arches, on which, finally, is elaborated an exquisite arrange- ment of solitl points iqion which important mechanical functions devolve, in the move- ments of the ap[)aratus of respiration.* The • As it is the design of this paper to refer no more to the descrijitive departments of comparative anatomy than is found indispensable to elucidate questions of ultimate structure, I must refer the reader, for the solution of the homological and tele- ological details on this subject, to the work of Prof. u 290 EESPIRATION. gill-bearing arches are not composed of single undivided curveil bones, but of several ele- ments, adjusted with express reference to the elasticity and flexibility of the whole. .Six of these arches are primarily developed, and five permanently retained. The first four support gills, the fifth is beset with teeth which giiaril the opening of the gullet : this latter is termeil the pliaryngeal arch ; the rest the branchial arches. From the convex side of the branchial arclies a double series of interlocking penknife-shaped processes radiate. On the fiat surfaces of these pro- cesses a gorgeous arrangement of mem- branous leaflets is disposed in a transverse manner, each leaflet standing, as already tie- scribed, on its etlge(y%. 237.). This rich foliage, bearing the complex web of the respiratory capillaries, is itself sustained by a machinery of elastic solid parts, hitherto unknown in comparative anatom^'. The series of curvilinear bones denomin- nated the arches of the branchiae, and exhi- bited in section at a, fig 237., are interiorly attached to the sternal chain of bones, pro- ceeding upwards and backvvards, and describ- ing a curve, which in different genera varies in degrees of sharpness, and which finally affix themselves by means of ligtiments to the base of the cranial bones. These curved bones are constructed of several separable pieces, adjusted with artful reference to the resilient properties of the curvilinear figure. The act of opening the mouth in the fish deter- mines a consecutive series of movements, which end in the jireparation of the gills to be traversed by the branchial current. By an appropriate intervening mechanism the move- ments of protruding and retracting the mouth occasion irrespectively the approximation and separation of the branchial processes, accom- panied by an alternate inci'ease and tlecrease of the curvature of the sustaining arch. The straight penknife-shaped processes (1. 2. fig. 239. .r.),as stated, diverge from the convex- ities of the branchial arches. In nearly ail the osseous fishes, these processes form a double series, the gills being accordingly dis- tinguished as bherial. In those genera in which these processes form a single line the gills are said to be uniserial. In the genera coitus (bull-heads), lahroidcc (rock -fish or wrasses), sebastes, (Noiwvay haddock), scorpaenidae (hog-fish), Teidse (John Dory, &c.), the nilotic-fishes, polipterus, gobroidae (blennies and gobies), Icjiadogaslides, a genus of small sucker-fishes), and the cyclopterids or lump-fishes, may be ranged under one great group, chai'acterised by three biserial and one uniserial fiW. The genera sophiidae (angler), batrachoidae, the tetraodons (or globe-fish), Owen on Fishes: Ryiner Jones’s Animal Kingdom; Article Pisces, in this work, by Prof. K. Jones; Art. SivicLETON, by Mr. Maclise. I wish only here to observe, that the branchial arches appertain to the apparatus of the visceral skeleton, and in antero- posterior order succeed the hyoid arch, on the key- stone of which they are more or les.s dependant, and the altered configuration of which they more or less follow. the diodons (commonly called the sea porcu- pines), and that curious genus of monop- terus found on the seas of the Molluccas, the gill opening in which is united by transverse partitions of membrane, are characterised by three symmetrical biscrial gills. Other le-.s regular genera present other diversities in the disposition of the branchial processes * The [lenknife-shaped processes (^fig. 237.), which radiate from the convexities of the branchial arches are bony in the osseous fishes; but only that part of the solid basis of the process is bony which corresponds with and forms the substance of its blunt or thick margin. In the cartilaginous orders this por- tion is composed of cartilage, the component cells as well as the outline of which are very dissimilar to those of the former class. As in- dicated in the above illustration, that piece in the skeleton of the branchial process which forms the obtuse border exhibits a groove seen sectionaliy at (J), b, fig. 237.), serving for the lodgement of the processal branch (g) of the branchial artery. The internal edge of this bony piece is dentated by pro- jecting spines, adapted perfectly to support Fig. 238. Plan exhibiting the skeletal framework of the lamellre | of the gilts of Fish in transverse section. {^Ori- f ginal.') . a, shows the osseo-cartilage of the obtuse margin . of the lamella, presenting three distinct varieties of component cells, and on the external edge opening A. I into a groove for the lodgment of the branchial J' 1 artery a', from which, on either side, the ultimate j ramusculi, emptying themselves into the rete mira~ > bile of the leaflets, may be seen to proceed; b and [ c, c', define the beautiful framework which lies pa- J, rallel with the acute border of the lamella, the '■’r lateral processes c, c' stretching on either side along | the circumference of the membranous leaflets, pic- ' venting, by their continuously acting elasticity, ” - the injurious folding of the latter, and, tlierefore, i the tangling of the respiratory web of capillaries. The extremities of these processes are produced by means of the curled clastic fibres shown in the plan. The dotted lines define the area of tlie rc- sjiiratory membranous leaflets supporting the ca- 5 pillary network. J * See Yarrel on British Fishes ; Leijons d’Ana- tomie Coinparee, par M. Cuvier ; Owen's Lec- tures on Comparative Anatomy, vol. ii. ; Monro, on the Structure and Physiology of Fishes, 1785 ; Art. P1.SCES, in this Cyclopaidia ; Wagner’s Ana- ’ toni}' of Vertebrated Animals, by Tnlk, 1845. RESPIRATION. the soft structures. This part is re|)resented 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 labyrinth 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 with 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 ba.se to its extreme apex. From either side of this proces.s, at right angles, processes (f and ce)> still more slender, delicate, and trans- parent, are detached, to follow ibr some dis- tance the circumference or free margin of the membranous leaflet on which the vascular network is outsfiread. 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 oft' into a species of curl}' fibre, which Iravels accurately along the extreme margin of the membranous leaflets to the point (a) 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 with 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 jiarietes of the cartilage cells. It is not easy to misappre- 29i 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. ]\Iorhid 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 jjathologists. 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. Devi.ations 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. Hyperannia and Anaemia. h. Inflammations of the mucous membrane. U 2 292 RESPIRATION, 1. Catarrhal inflammation. a. Acute. h. Chronic. 2. Exudative processes (croupous inflam- mation.) 3. Pustular inflammation. 4. The tt'phous process on the mucous membrane of tlie air jtassages. c. Inflammation of the submucous areolar tissue. d. Ulcerous processes. e. UEdema of the mucous membrane of the air passages. f. Gangrene of the air passages. (j. Adventitious products. li. Diseases of tlie cartilaginous skeleton of the air passages a. Inflammation of the perichondrium of the laryngeal cartilages. A. Inflammation and softening of the epi- glottis. c. Ossification. d. Adventitious products. 7. Anomalies in the contents of the air pas.sages. Abiinrimd Conditions of the Lungs. 1. Deficiency and excess of formation. 2. Anomalies of size. — Hypertrophy and Atro|)hy. 3. Anomalies in form and position. 4. Diseases of texture. a. Itarefaction of the pttlmon.ary tissue ( Emphysema.) 0. Condensation of the pulmonary tissue. c. Ilypatremia (stasis). Apoplexy of the lungs. d. Anajmia of the lungs. e. Cl'idema of the lungs. f. Intlammiition of the lungs (Pneu- monia). 1. Croupous pneumonia, typhous ))ueumonia. 2. Catarrhal pneumonia. 3. Inflammation of the interstitial tissue of the lungs (Interstitial jmeumonia). g. Deposits m the lungs (Melastatic processe.s). h. Gangrene of the lungs. 1. Softening. h. Adventitious products. The preceding distribution of the morbid conditions of the air passages may he advan- tageously mctliodised under two heads : first, those ol tlie bronchi (as definetl in the account of their normal anatomy) ; secondly, those of tlie lungs. 'file bronchi are liable to several forms of inflammation : a. Acute bronchitis. b. Chronic bronchitis. c. Plastic bronchitis. Collapse of the lungs should be considei'ed, 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 saccidar. The * For an account of tlie morbid statis of the larynx, and upper part of the trachea, see Art. Laiyiix. 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 as]iects, 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 |iresents a dark violet colour as seen beneath the pleura ; internally it is red. In considering the causes which tend to [iroduce 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 ob.struction according as it is more thick and viscid ; and 2ndly, weakness or inefficiency of the respiratory power; 3rdly 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 bi'onchitic collapse of the lung is almost always associated emphysema of the unaffected portionsofthesamelung(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 superflcinl 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 tins 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 snr une Distinction nouvelle de deux Formes de la Bronchite; prdce'de de quelques considerations generales sur I'inflamination de la membrane mu- quese des voies-aeriennes. Par J. FI. S. Beau. Archives Gendrales de la Bledicine, Sept, et Oct. 1848. Mdmoire sur quelques Parties de ITIistoire de la Bronchite et de la Broncho-pneumonie chez les Enfants. (Archives Gdnerales, Oct. 1851, et suivantes.) Memoire sur la Broncho-pneumonie Vesicnlaire chez les Enfants. (Revue Mddico- Chirurgicale de Paris, 1852. Par les Drs. Barthez et Rilliet.) Traite Pratique des Maladies des Nouveaux-Nes, &c. Paris, 1852. Par 31. Bonchut. S A 3Iemoir by Legendre and Bailly, in the Archives ^ Gene'rales de 3Iedicin, on the “ e'tat foetal ” of the Ji lungs, tom. Ixiv. On the Diseases of the Organs of E Circulation and Respiration, Art. Atelectasis. By f Ilasse. Sydenham Society. Die Bronchio-pneu- nionie der Neu-gebornen und Siiuglinge. Berlin, 1837. By Seifert. Medico-chirurgical Trans., for 1830. By Dr. Alderson. Der Mechanismus der Re- spiration und Circulation. By 31endelssohn. Beitrilge zur Experimentellen Pathologie und Physiologic. By 31. Traube. Die Bronchitis der Kinder. Leipzig, 1849. Dr. Fuchs. Diseases of Infancy and Child- hood. West. RESPIRATION. 293 areolar tissue, being accumulateJ 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 hypertro2'ilig, mucous jiolypi, ejjilkelial growths, sponsp Mvl velvety thickening, relaxation of the muscular and fibrous elements, yo//ia(/ar ulceration, &c. The pathological conditions of the broncho- pulmonary 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 ofl' 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 ; haemorrhage; 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 [iliysical condition of the exuded product. The first is that of engorgement ; the second is that of hepalisation ; the third is that of grey 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 secondai'3’ nodules and primary infiltration, accompanied or not by tuberous formation on either mediastinum about the main right bronchus (Wa'sh). 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 seat 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. I'he 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 comlition of the nutritive material (Dr. C. J. B. Williams). Tubercle is composed of the products of inflammation , (Reinhardt). 'rubercle is composed of the dead-tissue elements (Henle). 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 judice. 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 collapse has hapjiened in another part. Em- physema fills up pneumatically the space lost by the collapse, and no more. The chest can only be filled ; it cannot be inflated beyond a given ins|iiratory 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 Wdliams.') STOMACH AND INTESTINE.— (Syn. Stomach, formerly Maw, Eng. ; Magen, Germ.; ffTo/j-axoc-, yaarnp, Gr. ; Slomachus, Ventriculiis, Lat. ; Stomaco, Ventricolo, Ital. ; Estomac, Fr. ; Estomaco, Sp. ; — Intestine or bowel, formerly gut, tripe, cut rail, Eng.; Darm., * See British For. Med. Clu'r. Rev., for January April, July, 1853 ; in which Nos. respective^ three e.xcellent articles by’ Paget, Jenner, and Sieveking, will be found. u 3 294 STOMACH AND INTESTINE. Germ. ; ivrepov, Gr. ; In{es!inum,ljat.;Inleslino, Ital. Sp. ; Intestin, Fr.#) Wliat are called the organs of the animal body consist of a tliversity of tissues, so groupeil and united with each other as to form a more or less continuous and aggregate mass ; — the functions of these various struc- tures hein;; also associated in a single general purpose, which may he 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- siile 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 wdiole, 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 [lerhaps 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 ; — Tlie word ycurTr,^ is radical. The stomach is so called from its connection with the month (irTo.M.oij. 3Iaw and viagen are de- rived from its relation to food {meat). Intestine, ivrt^cv, entrail, ventriculus, (and darm?) connote its internal and liidden position. Bowel (ImteHus), and tripe (v^iTEo;), refer to its convoluted or tortuous form ; gut (geotnn, 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 stibstance. 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 compound.s 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 |)roducts of a previous organization. The elaboration of the food repeats the lireceding 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 theanimal 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 mitritioussuhstance 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 |irehension 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 tenqierature often necessary to the operation, j- * Traces of this contrast between the anim.nl and plant daring life may be found in tliose proce.sses of putrefaction and eremacausis which respectively efl'ect 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 wliich mere reception is so predominant, that Ave might almost compare it Avith the absorption of the ch3une and chyle into the blood. As a kind of fanciful corollaiy to this, Ave might regard the crust of the earth, and the atmosphere Avhich sur- rounds it, .as forming a common stomach or recep- tacle of food for the Avhole vegetable kingdom. For theA' include, or receive, detain, and give up, the che- mical food of the plant ; — in quantities which, though STOMACH AND INTESTINE. 295 The reader will, however, observe, that the title of the following article does not announce an essay on the process of digestion, or tlie various organs which effect it ; but limits itself to two portions of the alimentary canal, hitherto uiidescribed in this work. But it is impossible to treat of the functions of the stomach and intestine except in connection with the entire process in which they take so large a share. While the numerous observa- tions and researches which have been marie since the appearance of the earlier article Digestion require some notice in the Supjilemeyit of which the present essay forms a part. For these reasons the author has felt it advisable not to confine himself too strictly to the exact limits which the heading “ Sto- mach and Intestine’’ might seem to imply. Hence, though the following essay will treat chiefly of the above segments of the alimentary canal, it will also comprise a very brief account of whatever is at present known concerning the whole digestive act. Commencing by a rough sketch of the anatomy of these parts in the animal kingrlom, 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. CoMPAitATiVE Anatomy. — In the Infuso- ria, whose minuteness places them at the lowest extremity of the animal kingdom, the 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 and exceptional condition : — viz. the absence of all traces of digestive cavity. Such are the parasitic Gregarina and Opalinn ; in whom, as in some of the Entozoa, digestion and absorption appear reduced to a simple phy- sical process of endosmo.se, which carries the nutritious substances dissolvetl in the fluid medium they inhabit at once into the mass of their corporeal juices. The Poli/gastria possess a plurality of stomachs or internal sacs ; and the relations of these to the intestine, together with the con- dition of the latter tube, subdivide this group into numerous families and genera. Thus many are named “anenterous,” because they appear to be devoid of intestine. Of these the Monas termo — which has four or five globular stomachs, of 2,ri_^th of an inch in diameter, appended immediately to its mouth — may be taken as the tjqie. Others possess similar sacs in connection with a simple Intestine ; and are chiefly distinguishetl by the sti'aight, curved, or wavy course of this canal, — or by the single or double character, and lateral or terminal position, of its apertures. Most of them devour a living prey of kindred Infuso- 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 class or species, and renewed by an artilicial supply. is aided by a dental apparatus, in the shape of a h-illow cylinder enclosing long teeth, — as in the genus Napula. The Rutifcra are so named from the cur- rents produced by their prehensile cilia ; which are here limited to groups surrounding the mouth of the animal. Many of them have an organ of mastica- tion. This usually consists of three pieces : — each of the tw o facets of a kind of anvil being worked upon by the rough or toothed terminal surface of a recurved jaw, the longer limb of which receives a muscle at its extremity. The intestinal canal generally exhibits a pharyngeal enlargement, which is followed by a narrow ‘’oesophagus,” of vatu ing length, ending in a wider “intestine.” In the Gasterodela a dilatation, called a stomach, pre- cedes the intestine. In the Rotifer vulgaris and others, an almost globular enlargement of the narrow canal is so immediately followed by the constricted cloaca, as to have been com- pared to a large intestine. The organ of digestion is also often complicated by the 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, or into the presumed gastric dilatation; — or, finally, as in the Diglrsna lacustris, a set of such tubes may occujiy both of these latter situa- tions. The various members of the order Entozoa are grouped together in obedience to a classi- fication which is here and there arbitrary and 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 Echinococci and their congeners — no trace of a special digestive cavity is present. Without mouth, stomach, or intestine, the creature floats free in the cavity of its enclosing cyst, or buries its barbed head in the tissues' of a living habitation; — whose juices, thus brought into relation with its exterior, are applied to its nourishment by what seems to be rather a process of endosmose than of digestion pro- perly so called. l3. In other genera belonging to the Cestoid and Tremntoid divisions, there is, however, a canal, which is apparentl3’ related to digestion, and the main features of which — repetition ami ramification — may be represented b}' the Teenia and IJistoma respective!}’. For example, in the Tape-worm, a minute mouth opens into a slender tube, the bifurca- tions of which reach the margins of the body 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 these canals possess valves. But whether tney have any constant or valid terminal ori- fices seems doubtful. u 4 STOMACH AND INTESTINE. Many species of Distcma or Flnke may l)e regarded as types of an arborescent or I'ami- fied dige.stive tube. From a inontli 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 scries of anastomosing twigs. y. In many creatures closely allied to the jireccding by conformation and habits, this raniifieil canal is reduced to its primary bi- I'urcations, the ends of which ai'e sometiinc.s slightly tlilated. Occasionally there is an enlargement, which has the situation of a [iha- rynx ; and which, in a few instances, encloses an apparatus perhaps masticatory. In the genus Diplostamum and others, a distinct set of vessels, which occupies the immediate neigh- boui'hood of the intestine, has been supposed to rc|)resent a chyliferous or vascular system. As regards these latter forms of digestive apparatus, it may be conjectured, that the ramilication witnessed in the Tama 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; whde it sometimes visibly coinciiles with the appearance of a new system of canals, con- nected with the circulation of a proper nu- trient fluid. In the Newatuid 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, Tricoccphahis, A.scaris, S/rongptiis, ami others — it witlens posteri- orly ; where it often ex|)criences a further dilatation, which only ceases near the anus. Karely, other indications of separation are added : — an oesophageal dilatation, as in the A.icaris lumbricoidcs ; or an enlargement cor- responding in position to a stomach, as in the Linguahda and Fi/aria. Kudiments of the organs accessory to di- gestion have also been detected. Jllind 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- gartled as salivary. While rarely there is a tube w'hich 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 Fiifozoa offers a marked contrast with the preceding. In the Stcrclmintha (or solid worms) the tube is scarcely distinguishable from the mass of the body. While in these Ccclelmintha (or hollow Ncmatoid worms), it is sus|)ended from the wall of the belly by filamentous [iroccsses. And though such an acquisition of an abdominal cavity is no doubt partly rcferrible to the isola- tion demanded by the organs of locomotion, yet not only does this itself imjdy a general advance of develo[)rnent, but it" is actually accompanied by a curious structure, which is apparently connecteil with nutrition, and pos- sibly renders the cavity of the abdomen the receptacle of a kind of chyle. Its more perfect form in the ylscaris lumbricoidcs 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 wdiich 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 Folpp exhibits so wide a range of development, that while by one extreme it approaches that of the sim- plest anentcrous Infusoria, by the other it attains a complexity akin to that of the highest Invertebrata. The Hydra is little more than a stomach or sac, fixed by a sucker at its closed extre- mity, aiul having at its other end a month 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 the animal; 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 Actinia — the folded bag formed by the stomach is separated from the mouth by an oesophageal constriction. It is at the same time attached to, ami isolated from, the general wall of the animal, by ratliating mus- cular bands ; which extend vertically dow n the whole depth of the organ, so as to resemble the septa of a popjiy capsule as seen in a transverse section. The comjMund 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 Anthozna 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, wdthin which they experience a kind of circulation. In the Tubularian Polyp, the canal is modi- fied by the aildition 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 [ilace of its attachment being marked by an internal constriction, through which the cavity of this apfiendix 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 297 STOZvIACII AND INTESTINE. species. Some of the circulatory movements its primary divisions attached by a kind of observed in their ingesta are perlia[)S accom- mesentery. plished by the aid of s"uch an apparatus. While In the Echinus, the anus generally opens on their vigorous and almost peristaltic character the up[)er or opposite surface of the boily. in other instances is due to structures, the Many of this genus have a complex inasti- voluntary ami powerful contractions of which catory organ, which is acted upon by powerful entitle them to rank as muscles. muscles. The first part of the canal opens 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 Acalephce 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 onl}'. 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 Ecldnodermata again presents us with an important advance of development in passing from its lowest to its highest members. Thus the alimentary canal of the Astcrias 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 cmca. In Comatida the cteca 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 into an intestine of much larger diameter, opposite to a bliml 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 exliibitinga 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 Holothurice 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 whicii 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, tliat it is diffi- cult to include all the varieties of their diges- tive apparatus within a mere brief sketch. Tlie 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 aitled by teeth, w liich, as in the Leech, perforate the skin of their prey; while in other.s — as in some of the Eirantcs — it is effected solely by a proboscis. In many of the marine Erranles 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 [>art of the tube is com- plicated by being (iroduced 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 Ajjkroditci, th.ey 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 tpphlosule. 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, that the animal, when alarmed, can shed the whole canal. This extraor- dinary act is presumed to he voluntary, and is only paralleled by tlie growth of another digestive ap'- paratus, which replaces that evacuated. STOMACH AND INTESTINE. 298 projecting into its cavit_v. Its interior surface is I'olded and villous. The whole structure ap[)ears to be connected with a kind of chy- lous absorption. The alimentary canal of the Epizoa differs from that of the cavitary Entozoa, in being generally surrounded by a glandular mass, the function of which is probably he[)atic. The Cirri)ieda have prehensile jaws, and a ter- minal mouth and anus. In some, the canal has a gastric dilatation. Hepatic follicles, similar to those already ilescribed, occur here also. Anil St. Ange and Serres have Ibund a tube analogous to the tyjdilosole. The digestive tube of' the Crmlncea may be reduced to two chief forms, which corre- s[)ond 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 wdiich are clustered a dense mass of follicles, supposed to constitute a liver. The hir.her Ci'ustaceans possess a complicated apparatus of forceps and jaws. A short cesopbagus 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 cffical 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 Xowerxlnnclida : being a straight tube, with a mouth and anus at opposite ends of the body. In many Hymenopterous larvae, the latter apertiu'e 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 doul)le 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 cfcca. In other instances, longer tube.s 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. Be.sides the complicated prehensile and dental a|)|iaratus, there is often an oesophagus, a crop, a muscular gizzard, a stomach, a small intestine, a large intestine, and a narrower I’ectum. 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 ci'op 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- nudation. ThegiK«a;Y/ 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 oesojihagus 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 cellnlated, or its cells are even prolonged into short cteca. 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 commeucementof thesmall 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 wdiich 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 Arachnidn 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 wdiich here, as often else- where, is only approximatively 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. The 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.” This is sometimes a mere dila- tation; sometimes is indicated by four sacculi, that radiate from a narrow tube; and sometimes presents a cavit}', 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- vaiy. And occasionally a special poison gland appears to empty itself in this neigh- bourhood. A middle set, called hepatic, often forms two pairs of lubes, with orifices much posterior to the gastric sacculi ; in other cases they are very numerous, and are con- cealed by a granular mas.s, which, occupies the same situation. The posterior set are one or two pairs of long cceca, 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 AloUusca, many of whom in- habit the sea, we may again trace a gradual ad- vance of development in the intestinal canal. The Turiicata is its lowest subdivision. Here a simple canal begins by a wide 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 ami outer surface of the animal. Sometimes the liver varies from this description in the fact that its follicles are aggregated. The Brachlopoda possess a digestive ap- paratus of nearly equal simplicity with the preceding. Dental structures are wanting ; and the liver is still follicular. The Lamellihranchiata 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 0|)en 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 a[>pa- ratus all reach a high development. The intestinal canal of the Ptcropoda 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 develojiment. Their mandibles form a powerful organ of mastication ; and, in many species, salivary glands co-exist. The moutli leads to a long and dilatable oesophagus, which descending, sometimes expands into a crop before it finally reaches the gizzartl or muscular stomach. 'J’his 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, ojiens into it by a single duct. The intestine continues hence as an uniform lube, which, after one or two’ slight curves, bends upwards to open at the base of the funnel. In some species we also find cascal 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 dilatation. The use of this implement is unknown ; but it lias 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 liave 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 (jEsophagus, a stomach, anil an intestine. The (esophagus is large, dilatable, and mus- cular. Its mucous membrane is generally simple, sometimes involuted or glaiukdar ; 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 siulden increase in this situation the above contrast of structure is often the only distinc- tion between the two cavities. The sfonmrh varies greatly in size and shape. Usually, however, it forms a cui'ved 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 tidiewitha 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 a[)proaches 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, covereil 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 cascal tube. The intestine has the usual three coats — serous, musculai-, 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 inte.'-tine 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 * M.miy anatomists, hoevever, consider the office of this gland to be fullilled by the cavity previously inontioned. 13nt strong arguments against this view might be derived from the development of glands in general, and of the pancreas in jiarticular ; both in the phases of individual life, and in the advance of the animal series. In addition to this, the gastric ch.aracter of this cavity, and the unfitness of a giz- zard for solvent or digestive functions, further justify us in preferring the above interpretation. t Tlie 'rctroilon mola. + In the Tench (Ci/prinus tinea), they are Striped. § Iteversing their ordinary arrangement in the Mammalia II As in the Branchiostoma. 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 ap2)endices pi/luricce, 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, w'hich are united by areolar tissue and vessels, and are enclosed in a muscular tunic. The alimentary canal of lleptiles 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 [lai'ietes 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 gi'cat 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 Ojihidians 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 mu.scular fibres, that radiate from a central tendon on each side of the organ. The second is a small pyloric pouch or diverticidum, which passes out of the gizzard at its upper part, close to where it receives the dilated ossophagus. 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. Tlie pj loric 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 -il' circular constriction or valve. 301 STOMACH AND INTESTINE. In the BatracJiian division, however, the separation into these two segments is some- times absent. While 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 cfficum. 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-cacal 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-csBcal valve, and often a well-marked caecum. 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 cesophagus, which leads to the first of those cavities, has a length corresponding to that of the neck which it occupies. Its width and ililatability 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 cesophagus, somewhere about the miilille 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, vvhich 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 proventriciihis, com- municates with the inferior part of the oeso- phagus, and corresponds, both in structure anti function, with the true stomach of the Mam- 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 S[)herical 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 that 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 granivoi'ous 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 Reirtilian 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 ami apirearauce of its convolutions ; — diflerences 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 cteca otter remarkable differences in length : — varying from papilliform ott'sets, 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 bird.s 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 oixlers of Mammalia, that it 302 STOMACH AND INTESTINE. will be necessary briefly to state its pecu- liarities in eacli. In the Carnivora the shape of the stomach ap[)roaches that of the human oi'gan : it has a cardiac pouch, ami a greater and lesser curvature. The intestine is short, its length being to that of the body as* 5 to 1 in cats and clogs, and 8 or 9 to 1 in the hyajna 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 ctECum is short, and scarcely w’ider than the rest of the large intestine.f And the latter segment of the canal is short, wide, and cylindrical. The /«.scc/tTOra 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 catcum, 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 ap[iroaches 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 bv sucking the blood of animals : it dilfers 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- ceiling. 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 oesophageal a[)erture, and is divided into two bv a slight constriction, w hile its terminal or pyloric third is bent back so as to be ])araliel 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 cesophagus — which is somewhat dilated — differs from the upper. The pylorus is well marketl 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 pos.sess a simple organ ; the cardiac * We o-ive these measurements to jMeckel. + 111 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 Manis, 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, spi'inging from the right of the ])vloric aperture. In the Tardigrade genera the stomach assumes much of the complexity seen in the lluminantia. For it has two cavities, a caixliac ami 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 tlivided by prominent folds, and by' differences in the chai'acter 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 memltrane, 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 Ilu- 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 cesophagus. The latter tube also exhibits a cul-de-sac, which is sometimes further divitled 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 lar<;e and small intestines, ami open by what are sometimes extremely minute a|)ertures.* The Ruminnntia 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 honeycomh 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 maniplies 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 fVecal matter. But in tlie Dasypus mus/e- tinus, the ileum ends by' a slit between tlie larger apertiires of two sucli tubes; and hence appears to admit of lieing closed by the lateral pre.ssure of their contents. (See Prof, Owen’s Catalogue of the Hun- terian 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. the villi, 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 cavil}' or abomasum, is the true stomach : it secretes the gastric juice, and possesses the ordinary tubular structure. As reganls 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 once from the oesophagus to the maniplies. Packi/dermala. — Tlie 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 extremit}', and an intermediate portion, which receives the oesophagus. 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 e.x- ternal indications of the same subdivi.sions : but the wliite epithelium extends over a wider surface; so that it is only the pyloric third, and the lower [)arts of the midtile and cardiac pouches, which exhibit the proper gastric or tubular structure. In the Hippopo- tamus, the stomach is long and tubidar, 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 03so[)liagus 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.* The stomach of the Solipeda has a rounded shape, and a cardia and pt lorus wdiich are close to each other. The cardiac half of the organ is lined by a white e[)idei inis, 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 jiossession 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 fetal 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. Hut the tough and wrinkled character of the mucous membrane which lined the supposed abomasum in the greater part of its extent seems to negative this view. sncculation of the csecum and colon which ob- tains in this and the Pachydermatous order per- haps compensates such a diminution in length. Theilio-ctEcal valve is represented by a narrow passage, the mucous membrane of which forms six or eight thick longitudinal folds. The emeum, smallest in the Pachyderm, attain, s 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 ctecal tubes open into the large intestine by wiile apertures. In the Bodentia 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 conqfficated by the addi- tion of glandular crypts and casca, the im- port of which is unknown. The intestine of the Rodent is very long and convoluteil, and the small and large intestine are of nearly equal diameter; but the latter is deeply sac- culated. The ccecum 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. jSIarsupiaUa, — In a large proportion of this order, the stomach has a consiilerable 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 wliich are distinctly referrible to the habits of its possessors. In some, how- evei’, a stomach of very similar outsitle shape exhibits a lesser cuivature, which is oc- cupied by a gastric gland like that of the Beaver, composed of numerous irregular crv[)ts. In the Kangaroo both the shape ami 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 inters))ace 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 suh.- ject to great differences. The carnivoj'ous members of the class are devoid of a caecum. STOMACH AND INTESTINE. aoi The insectivorous Marsu{)ials 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 liave bowels which are still longer, and a large cxcum of twice the length of the whole bod}'. 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 ctecum is, however, much shorter. One genus, the Wombat, has a vermiform a|)pendix. I'lie length of the whole intestine varies from two to ten times the length of the animal. In the jMonolremata 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 ; mid is divided by a deep constriction into a "lobular cardiac, and a conical [lyloric, portion. Two large ca3ca ojicn into it near this con- striction ; and a special glandular apparatus occu[)ies 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 mucotis tnembrane. The biliary duct often opens into a, d.lated cavity, the import of which is unknown. Idle intestine is longer in the herbivorous tli- vision. Here tbere is also a ctEcum ; which is sometimes large and glaiulular, but some- times small, short, and even bifid. In tbe 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 Quadrumuna possess a stomach the form of which approaches that of the human organ. In some cases, however, it is more elongatei.1 ; while in others it assumes a glo- bular shape, with a cardia and |)ylorus in close proximity. The latter deviation is generally found in conjunction with carnivorous or insectivorous habits. It is usually separated into two portions, a carrliac tind a pyloric ; and sometimes the latter, which is more globul ir than usual, is distinguished by an internal fold from a short tubular part, which termi- nates in the pyloric valve and the duodenum, liudimentary [tyloric ctEca have been remarked by Cuvier * in one instance. The Sent- 'iiopilhccus presents a form of stomach which * Leyons cl’Auat. 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 tliis 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 I ; in others as .3 to 1 only. The division into two [lortions, ami 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 vai'iety 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 raucous membrane has villi, but no valvulce conniventes. General remarks. — Although physiology at present scarcely pretends to interpret this various and complex develojiment of the ali- mentary canal, still some attempt at its expla- nation is indispensable. For without any clue to their im[jort, details like the preceding could hardly be recollected, fiir 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 attem|)ting their ex[danation, can one be rightly charged with breaking those rules which our great countryman has laid down for the pursuit of natui'al knowlctlge. All that is necessary to such a sujierstructure of theory is, that, how- ever slight and temporaiw , 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 cavilp is the first peculiarity which demands our notice. The few genera in whom this rare condition has been found all offer tlie greatest simplicity of structure; and further agree in the fact that they are para,sitic :—i.e. that they derive their nutriment from the juices of another animal, to whose body they are attached. Hence we need not scru|)lc to assign tiiis apparent defi- ciency of the digestive organ, |iartly to the pre- vious elaboration of a highly nutritious animal food, partly to the sim[)licify of the various tissues which are destined to be nouiished by it. But can we therefore say, that the function of dige.stion is absent, oi-' — what would be nearly equivalent to such an assertion — that it is reduced to a mere phy sical 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 aliinentarv 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 iuice at p. 337. Supp. in the stomach. And the same impunity ex- tends to another animal of its owm species which may have been swallowed wdiile 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 | 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 antitliesis 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 fi'om 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 stomaclial dilatation ; a subdivi- * It is interesting to notice that dift’erences of development, such as are obviously almost tanta- mount to diversity of species, appear to remove all barrier to this solvent action. Thus the Polypifoi'm Medusa devours and digests its Infnsoiy-like3munger brethren. t See p, 335. j The term “ chylific stomach,” sometimes made use of b>' comparative anatomists, seems especially to demand such a caution. For ive need scarcely point out that, in the higher animals, at any rate, this organ does not “make clnde.” X STOMACH AND INTESTINE. 306 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 (|iiality 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 [jurpose: — 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 a]iproaches that of the body and limbs respectively. But even this peculiarity of form is probably teleological. 3. Sufficient allusion has alreadyf been made to vegetative or irrelative re[)etition, 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 Distomae — 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. Tliey are generally, and * In this respect tlie inte.stinal canal may probably be contrasteil 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. 29.5. 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 boily, 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 as.sist 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 onr conjectures hy 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 ab.sorb 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. 307 STOMACH AND INTESTINE. 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 sanguims, 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 d 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,_/?g. 241.). An external constriction and an internal valve (p, fg. 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 cascuni 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, fig. 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, ciBcum ; a c, ascending colon; T c, transverse colon ; d c, descending colon ; s F, sigmoid flexure or sigmoid colon ; p,, rectmn ; 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 30B STOMACH AND INTESTINE. the trunk in which tlicy are enclosed ; and it limits, |)erniits, and facilitates those move- ments, vrliich 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 sup[)ly. The various modifica- tions undergone liy these constituents of the tube, in tiie 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. Fig. 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, and 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 240. Stomach and duodenum. The tube has been everted and inflated, and its mucozis membrane dissected off, so as to show the subjacent muscular coat. a ff, cardiac orifice; b h, pyloric valve; a e 6, lesser curvature, or upper border; g d f c h, greSiter curvature, or lower border. (The dotted lines joining a e, e b, and c h are intended to illustrate tbe inode in which extreme distention of the organ affects these curves) ; g d, cardiac pouch ; b h c e, pyloric pouch. (Ihe 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 ; ami hence its borders and its surfaces disappear by merging into each other. Its upjiennost part, however, is still distinguished as the lesser curvature {a, e, b, fig. 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 oeso[)hageal opening («), beyond which it projects for about three inches. At this aperture the oesophagus dilates gradually, so as to resemble an inverted fuuiv.l. To the right of the cesophagus, 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 (Jsb), 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 numeroustc' 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 rliameter 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 eftected by the continuity of its extremities * This woodcut is so far inaccurate, that the P3’loric constriction is shown more distinctly than it could be actually seen in such a view, in ivhich it would he partially concealed by the backward curve of this part of the stomach. 309 STOMACH AND INTESTINE. 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 altliough 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 jihreno- 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 gastro- splenic 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-hepntic or small omentum, vrliich de- scends from the transverse fissure of the liver. All of these folds are double; though the four layers of the reflected omentum niajus 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 hj pochondriac 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 ujiper 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 oblicjue 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 cesophagns 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 thep3loric extremity, and is often very sudden. 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 laminm, without undergoing any disturbance of its ner- vous and vascuhu’ 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 laminaj of peritoneum above mentioned, which split to enclose it w here they reach its various borders. Here they are very loosely connected to each other, and to the subjacent coat, by an abundance of higbly elastic areolar tissue. But towards the middle of the gastric surfaces, the peritoneum, though still clastic, 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 Meji- RRANES. The vntsailar 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 Jig. 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 to T^i^th of Fig. 241. \ \ Fibre-cell from the unstriped rmiscle of the intestine. 3Iagnified about 350 diameters. (After Koel- liker.') a, nucleus. an inch : their breadth from to ^’ooth 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 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 eonsist 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 (Jig. 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. 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 w'ould 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, ccsteris 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. 31 1 243.), it is inflected towards the axis of the stomach by a rather steep and sudden curve, which presents an almost vertical surface Fig. -243. Longitudinal section of the alimentary canal at the junction of the stomach and duodenum, to show the thickness of the pyloric valve. s, pyloric sac of the stomach ; d, commencement of the first portion of the duodenum ; p, pjdorus, formed by a thickening of the transverse lay^er of the muscular coat of the stomach. towards the duodenum. Those of the trails' 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,y%. 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 if, fig. 240.). The posterior or thinner part proceeds, not only from the depression (gyfig. 240.) on the left of the cardia, but also from the neighbouring up|ier 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 ofeach 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 “ fflsoeiiAGUs” and “ Pharynx.” X 4 312 STOMACH AND INTESTINE. stomach.* This coiulition 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 eliectively 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 oesophageal fibres, and how much to the shape, position, or structure of the stomach itself. Iiuleed, 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 ins[iiration, produces an increase of contrac- tion. f 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 movemrnts 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 marketl, 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. G2, 63., and elsewhere. Valentin, Lehrbuch der Phy- siologic, Band i. p. 269. Magendie, Precis eld- mentaire de Physiologic : Quatribmo edition, vol. ii. p. 70. f Op. cit. pp. 81, 82. X Magendie {he. cit.) and Mueller (Handbuch der Physiologic, Bd. i. p. 412) state that an alter- nating and rh3dhmical movement of the oesophagus accompanies digestion. It is independent of tleglu- tition. The contraction of the tube coincides with the period of inspiration ; and, vice versa, its relaxa- tion with expiration. But sucli results of vivisection cannot be safely regarded as the ordinaiy pheno- mena of the healthy body. As to how far the cardia is necessarilj' 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. § Blagendie, he. 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 w hatever. This fact, which is asserted by Dr. Beaumontf , from his obser- vations on the living human subjeet, 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 exce|)tion 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 eontracted 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 quantitj' 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 Babbit, 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 Babbit, both the stomach and intestine appear to be unusually sluggish ; as shown b,y 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 digestive 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- se'"ved ? (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). t 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 Phj-siological 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 (d, J?g. 24-4.), 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 (d). This retrograde course is, 2Jro tanto, a current ; and one which will be continually lengthened by the advance of the septum along the remainder of the tube. And the slow successive movement of a series of such septa would establish two con- tinuous currents in the liquid; a peripheral of advance, and a central of return.* Fig. 244. Diagram to illustrate the effects of peristalsis in a closed tube containing liquid. a, Closed end of the tube ; b, perforated septum, moved towards a, and causing the peripheral cur- rents indicated by the arrow's, in the same direction ; c, quiescent mass of liquid, giving origin to d ; d, central current, prolonged from the corresponding arrow, and passing through the perforated septum. The existence of two such currents would be little affected by the membranous nature or peculiar shape of the human stomach. Even comparative inactivity of the cardiac pouch would not prevent their occurrence, as a consequence of pyloric peristalsis. While very moderate contractions of this sluggish part would accurately define the axis and its cur- * The following description so well supplies the interval between such a model tube and the human stomach, that I cannot refrain from quoting it. “ The muscular action of a fish’s stomach consists of vermicular contractions, creeping slowly in continu- ous succession from the cardia to the pylorus, and impressing a twofold gyratory motion on the con- tents ; so that, while some portions are proceeding to the pylorus, others are returning tow'ards the cardia.” (Owen’s Hunterian Lectures, vol. ii. p. 236.). 314 STOMACH AND INTESTINE. rent, as that curved line wliich unites the car- diac and pyloric apertures (a, fig. 245.). Fig. 245. Diagram to show the general direction of movement impressed on the semiJJuid food in the digesting stomach. a, real axis of the stomach, uniting its cardiac and pyloric apertures ; J, situation of the abnormal opening in St. Martin’s case. (The arrows corre- spond to theperipherial current of advance, which is elFected by peristalsis; and the central current of return, which is reflected from the preceding at the pylorus.) (2.) The observations of Dr. Beaumont are as follows*: — “The bolus, as it enters the cardia, turns to the left, passes the aperture, descends into the splenic extremity, and fol- lows the great curvature towards the pyloric end. It then returns in the course of the smaller curvature, makes its appearance again at the aperture in its descent into the great curvature, to perform similar revolutions. These revolutions are completed in from one to three minutes; the bulb of the thermometer invariably indicates the same movements.” lie is careful to add, that there is an admix- ture of the ingesta, which implies that the movement is not simply a revolution ; for that, if this were the case, “ the central portions would retain their situation, until the outer or chymified part had passed into the duode- num.”f Now in order to render the movement thus observed perfectly compatible with that above deduced, we have but to recollect the situation of the aperture from which the inspection of St. Martin’s stomach was made. This was at the left extremity of the organ (5, fig. 245.). Whence it is obvious, that any backward movement along the real axis (rt), connecting the two orifices of the stomach, would be so near to the superior curved border, and so far from the point of view, that Dr. Beaumont could scarcely have avoided imputing to it the course which he has done. While, since every part of the stomach would be occupied by one or other of the two currents, the mutual interference of these at * Op. cit. p. 101. t Tins admixture he ascribes to a triturating or agitating motion, which is partly gastric, partly re- spiratory. But the existence of the circulating movement described sutRciently proves that tliis mixture was inherent to tlie process, and not (as his supposition would imply) a result of its disturb- ance. their borders must gradually cause an uniform diffusion of the various alimentary matter.s moving with them. And finally, the reflec- tion of one current into the other at the pylorus, insures an equal contact of all the semifluid food with the surface of the mucous membrane; since those portions of the in- gesta which occupy the axis of the stomach during one moment, are destined to move along its periphery during the next. 3. In the later stage of digestion, the move- ment seen in the Dog’s stomach soon after death differs from the preceding. The cardiac extremity appears even less active than before ; and the longitudinal shortening of the organ is also less marked. The chief visible commencement of contrac- tion is at the same place where it was for- merly increased, and where it now forms a deep constriction or hour-glass contraction. After this constriction has continued a short time, it sends onwards towards the pylorus a rapid peristalsis, which appears nearly to ob- literate the tube in its course, and ends by engaging the muscular ring of this valve. A slight relaxation closely follows this peristal- sis ; and is succeeded by a complete dilata- tion of the pyloric sac. Lastly, the hour- glass contraction itself sometimes disappears; and an interval of about two minutes precedes the repetition of the whole process. Often, however, the constriction remains until the peristalsis recommences. Dr. Beaumont’s observations ’’’ again seem to supply the counterpart to this description. He states that, when chymification has ad- vanced, the motion is quicker. And on attempt- ing to pass a thermometer tube towards the pylorus, it is stopped by a stricture f, which is situated about three or four inches from this aperture. A forcible contraction is first per- ceived ; but in a short time, there is a gentle relaxation, when the bulb passes without dif- ficulty, and is then drawn forcibly towards, the pyloric end for three or four inches. It is then released, and forced back with a spiral motion for the same distance, when it seems to be again obstructed by the stricture. But if pulled up through this, it moves freely in the cardiac portion, mostly inclining towards the .splenic extremity. The repetition of the con- traction is preceded by an interval of about three minutes, during which the food revolves as in the previous stage. It is scarcely necessary to point out, that when the almost obliterated pyloric tube is , filled by the tightly grasped thermometer bulb,‘ no axial current can possibly be produced by.;- the peristalsis. The pylorus having con-' tracted, and its pouch relaxed, the contrac- ■ tility of the whole organ would determine a rush of fluid around the bulb; and this would be reflected from the valve into the axis of the , * Op. cit. pp. 102. 104. t The similar narrowing seen in the digesting ■ stomach of animals has been called the “ transverse band” ; a term which is objectionable, inasmuch as it implies the presence of a special structure that does not really exist. STOMACH AND INTESTINE. 315 tube. We should thus get two currents, which, at least in situation, would be identical with those produced by the peristalsis of the succeeding interval. Action of the 'Pylorus. — The structure of the pylorus (TTvXoiphg, portce custos) has already been described. As regards its action, it is obviously the sphincter of the stomach. As such, it has been supposed to possess a kind of selective power ; by virtue of which it contracts against the food in the earlier stage of digestion, but subsequently relaxes to per- mit the passage of the chyme. This view, however, appears to me very doubtful. In the empty stomach, the pylorus is generally open, and readily* allows of the passage of bile from the duodenum. In the early stage of digestion, it is firmly shut ; and retains the contents of the organ against gravity, or even against such a manual pressure as readily expels them from the cardia. But just as in the second stage of gastric digestion, it is plain that the valve does not undergo any sudden or great relaxation, — for such would allow the passage of a large quan- tity of the moving and semifluid food, much of which would be still crude and undigested — so the very gradual diminution-}', noticed by Beaumont in the early stage, renders his in- ference,— that, even from the first, chyme is constantly passing into the duodenum — very probably correct. J Supposing this to be the case, it is evident that the action of the pylorus must be very similar at both these periods. And after numerous and careful observations on this part of the Dog’s stomach towards the close of its digestive act, I have never yet been able to substantiate any de- finite relaxation of the pylorus ; or any but an inconsiderable oozing of chyme at the time of that active peristalsis which has been described above. Hence I prefer to regard the passage of the chyme as produced by that great increase of force which the contractions of the pyloric sac acquire at this period; — a cause which appears so sufficient, that it seems scarcely justifiable to assume any additional one. The supposed relaxation of the pylorus seems also contradicted by a remark of Beaumont’s, that, even at the end of the process, when the passage of chyme is greatly accelerated, tlie above contractions still continue. In short, instead of a relaxed pylorus, through which a moderate peristalsis urges a selected portion of the food, it appears * Bile is almost always found in the empty stomach of Dogs and Cats. (Compare Beaumont, pp. 86, 87.) The diminution due to absorption would pro- bably be at first compensated by the addition of gastric juice. t According to Magendie ( Op. cit. p. 91.), the py- lorus of the Horse is always found open, and is pro- bably relaxed during life. It is only thus one can explain the well-kuowm fact, that the quantity of food taken by this animal at an ordinary meal has a bulk which amounts to four or five times that of its distended stomach. Indeed, water has been found in its cmcum six minutes after being swal- lowed. (Coleman in Abernethy’s Physiological Lectures, p. 180.) the state of this aperture during the close of gastric digestion is that of a contracted valve, through which the tolerably uniform chyme is being strained in small quantities, at fre- quent intervals, by a comparatively violent muscular contraction.* Hence the separa- tion of the chyme from the other contents of the stomach seems to be eflected by a pro- cess somewhat analogous to a coarse filtra- tion, aided by pressure. How little the pylorus could reject the “crude” portions of the tolerably homo- geneous chyme, to transmit its more fluid or dissolved constituents, is shown by the facility with which indigestible substances of various shapes and sizes pass into the duodenum. Of these we can only say, that it is probable they are generally carried through the con- stricted pyloric sac and valve by a very forcible peristalsis.-}- The weight and solidity of many such masses allow them to remain some time in the cardiac pouch, perhaps lodged behind the transverse constriction which separates this from the pyloric sac. Both of these circum- stances often defer their passage to the later stage of digestion. Smaller substances, how- ever, sometimes traverse the whole canal in so short J a space of time, that it is diffi- cult to avoid believing that they leave the stomach very shortly alter entering it. But while we may thus I'egard the pyloric valve as exerting but one and the same action during the whole period of gastric digestion, we shall find it difficult to substitute any other theory of its action for that local appreciation or selection which we have attempted to refute. Its contraction is ac- companied by that of the whole muscular coat of the stomach ; of which the pylorus forms, apparently, but a terminal thickening. And of the only two other facts which are co- temporaneous in their occurrence and dura- tion — viz., the presence of food, and of gastric juice — the first aflbrds little explanation ; while the second is more likely to be another effect of the cause, whatever it may be, which excites that co-ordinate muscular action in which the pylorus appears to play an im- portant, though simple, part. It is interesting to observe how little the action of the pylorus is connected with any stimulus other than a gastric one. The flow of bile into the fasting stomach may perhaps be regarded as a passage, such as this janitor might well concede to a fluid which is not only harmless, but recrementitious. But in * It is scarcely necessary to add, that the mecha- nism of such an act does not require that the cardia should he, however momentarily, the stronger v-alve of the two. For the force of an obliterating peri- stalsis would beat first almost spent upon the pylonis towards which it sets. While that of a weaker con- traction would be chiefly expended upon the py- loric sac. And the residual force of both would chiefly dilate the yielding and quiescent large ex- tremity. ■} A peristalsis, the energy of which it is pro- bable that they themselves increase. J Thus the author has known peas traverse the canal in two hours. 316 STOMACH AND INTESTINE. the obstructei! canal, fa;ces pass through it from the duodenum with equal facility, al- though the stomach soon resents their pre- sence hy vomiting ; — an act which seems generally to imply a shut pylorus. And Magendie* has observed, that the gases of this upper portion of the intestine can be made to pass the valve \vith equal facility ; while those distending the stomach excite its contraction. Under ordinary circumstances, whatever be the period during which the contents of the stomach sojourn in its cavity, or the movements they experience at this time, they are finally propelled onwards into the duo- denum. Sometimes, however, they take a backward course ; and [>ass through the (Esophagus, to re-enter the mouth, and be expelled from this cavity. Such a reversal of their normal direction occurs in the acts of eructation, regurgitation, and vomiting. These acts, however they may differ in their details, must (d priori) agree in the conditions of their oc- currence. They require a relaxation of ,tbe cardia, a closure -f- of the pylorus, and a com- pression of the stomach. The latter of these three requirements may either be the result of the contractions of the organ itself, or may be effected by an external or independent pressure. In simple eructation or belching, part of the gaseous contents of the stomach are ejected from the mouth. This act generally occurs towards the close of digestion, and in dyspeptic individuals ; the cpiantities of gas thus evolved being often very considerable. In what way the cardia is opened, or how far the evolution of large quantities of these aeri- form fluids in the stomach may not contribute to render it patulous, is at present very doubt- ful. But the intermittent character of the occurrence certainly looks unlike a mere leak- age of an aeriform fluid. While the frequency with which the human stomach contains gases, and the completeness with which the cardia resists their expulsion in vivisected animalsj, increase the difficulty of such a supposition, and, so far, tend to confirm that of a tem- porary relaxation of this aperture. The di- rect agent of the expulsive act seems equally uncertain. The contractions of the stomach seem quite sufficient to account for it. And there is certainly no violent abdominal pres- sure. But such mobile fluids would scarce require a remarkable effort. While, as far as can be judged, the act appears to coincide with the period of expiration. An examination of that voluntary eructa- tion which most persons can accomplish, may perhaps strengthen the conjecture, that some * Op. cit. p. 83. f Of course this closure need only be comparative : that is, the mere resistance of the contents of the stomach to compression would suffice to determine their passage through the more relaxed of its two orifices. J As in Magendie’s observations, elsewhere al- luded to. slight abdominal pressure is a constituent of the ordinary act. Here, by a kind of twitch- ing* action of the oesophagus, which is ac- companied by a sensation that is referred to the upper portion of this tube, air is intro- duced into its interior; and is then expelled, with a considerable sound, by a well-marked movement of expiration, during which the glottis appears to be at least partially closed. And the ex[)ulsion of the air artificially intro- duced is often accompanied by that of a por- tion which was previously contained in the stomach itself. So that involuntary and vo- luntary eructation may be said to merge into each other.+ In the act of regurgitation, more or less of the litiuid contents of the stomach are returned into the mouth. This act closely resembles the preceding, of which it often appears to be an accidental complication ; — a small portion of liquid being carried upwards, along with an eructation of gas. In other instances, how- ever, the liquid is unaccompanied by elastic fluid ; and rises so quietly, that it is only per- ceived on reaching the fauces and back of the tongue, where its acid taste causes it to be at once recognized. It is probable that the pro- cess which effects this expulsion is similar to that of eructation. If we could conjecture any difference, it would be, that the abclominal pressure plays a less important part. The act of vomiting differs from both of the preceding : not only in the miscellaneous character of the matters which it can expel from the stomach, and in the greater energy with which it is effected ; but also in the fact, that a pressure extrinsic to the organ itself here forms what is, at any rate, the chief agent of the process. This abdominal pressure, which has been before alluded to, we shall now proceed to describe. In those ordinary movements of respiration which are executed chiefly by the diaphragm and abdominal muscles, the bulk or capacity of the belly is little affected. For during the act of inspiration, the descent or contraction of the former, exactly coincides with the relax- ation of the latter muscular structures ; while during that of expiration, the compression which these exercise is neutralized by the re- cession or ascent of the now relaxed dia- phragm. Hence the moveable viscera of the belly themselves evade all pressure; and merely transfer a very slight force from the anterior to the upper wall of the cavity, or vice versa. But if, while the diaphragm re- mains depressed and contracted, the abdo- * This is often called a deglutition of air, although the movement is utterly unlike that of swallowing. + Thus the dyspeptic poor who crowd the out- patient rooms of hospitals, sometimes eructate so voluntarily, and even ostentatiously, that tlie act really seems to be done, not so much to expel gas from an over-distended stomach — as to attract com- miseration. And it is said that, in polite Chinese circles, a chorus of eructations .at the end of a banquet formally acquaints the host with the re- pletion of his grateful guests. STOMACH AND INTESTINE. 317 minal muscles be also brought into vigorous action, the whole force of either of these two muscular strata may be regarded as com- pressing the viscera within the abdominal cavity. And since many of these viscera are hollow organs, which enclose moveable con- tents, and communicate with the exterior of the bodj', such a forcible pressure will expel the contents from their interior, so soon as their terminal orifices are thrown open ; — whether by their relaxing spontaneously, or yielding to any superior force. In this way, the contraction of the walls of the belly plays an important part in the acts of defecation, micturition, and parturition, as well as in that of vomiting. Now in the three former of these acts, the intermittent abdominal pressure does but assist those more continuous expulsive contractions which are effected by the muscular walls of the hollow viscera themselves. And supposing that the cardia were open, and the pylorus shut, it is obvious that either pressure on the stomach, or contraction of its walls, would alike tend to expel its contents. Careful observation of the act of vomiting in any of the higher animals will show that it is always assisted by the abdominal pressure. And the vivisections which many experi- menters have practised, agree in carrying this investigation further ; and in stating, that this pressure, which ordinarily results from simultaneous contractions of the diaphragm and abdominal muscles, may be due solely to the latter * * * §, (as is normally the case in Birds f ), or to the former, or even to an inconsiderable compression exerted by the lower ribs upon the epigastric region.^ While the solitary observation of Maingault (J, which affirms the occurrence of vomiting in the absence of all such pressure, stands ex- pressly contradicted by the Committee of the French Academy appointed to report upon his Memoir. But whether the stomach really contracts during the act of vomiting, — and if so, what is the amount of assistance which it thus af- fords this process, — are questions which, long the object of physiological controversy, can even now scarcely be regarded as decided. On the one hand, there are not wanting experiments, which show that the act of vomiting may be effected without the aid of any gastric contractions whatever. Among such we may specially adduce the vivisection practised by Magendie ||, in which a Pig’s bladder was substituted for the stomach of a living Dog, and was subsequently emptied, by vomiting, of a large part of its contents. Such a result conclusively proves that gas- tric contractions are not essential to the physical act of vomiting, however frequently they may take a part in the process. And * Magendie, Sur le Vomissement, pp. 22. 37, 38. t Krimer in Horn and Nasse’s Arcliiv. 1816. j Bulletin de la Faculty de Medecine, 1813. No. 10. p. 481. et seq. § Sur le Vomissement. Paris, 1813. II Op. cit. p. 18. that inactivity of the stomach, which has been directly observed by many * physio- logists in the artificial vomiting of vivisected animals, has been all but actually seen in the living human j- subject. On the other hand, the observations in w hich a muscular contraction of the stomach has been seen to concur in this act, are even more numerous than the preceding. The amount of such contraction seen appears to have varied, having sometimes been so slight as to be scarcely visible. In all instances, it has specially engaged the pyloric extremity of the organ : and, in most, it is described as either circular J, and alternating with relaxa- tion; or peristaltic, like that found in the di- gesting stomach, independently of all vomiting. And though an anti-peristaltic movement is detailed by Haller and others, yet so far as I can find, this doctrine, which is expressly con- tradicted by the observations just referred to, rests only on one or two § vague descriptions of Wepfer, Rudbeck, and Schwartz. From these very brief allusions to both sides of this conflicted question, the author has been careful to eliminate every statement which does not refer to actual facts. And the reader must recollect, that not only does the stomach offer few obstacles to such direct observations ||, but that some of those summed up in the above statements, are ren- dered additionally trustworthy by being results quite at variance with the theories of their observers ; while others have been confirmed by very frequent and careful repetition. TT Hence, on the whole, I think we must con- clude as follows : — The act of vomiting is es- sentially, and perhaps sometimes solely, the result of powerful abdominal pressure on the contents of the stomach. It implies a pa- tulous cardia. The abdominal pressure which effects it, often coincides with, and is aided * Bayle, 'Wepfer, Chirac, Baciaecus, Senac, Schwartz, and (especially) Magendie. t Lepine, Bulletin de I’Academie de Medecine, vol. ix. p. 146. In this case, which has been strangely misquoted by mauj' Englisli authors, the stomach was protruded from a wound in the belly. It con- tained food and air, remained quite motionless, and could not even be excited to contract by manual titillation and pressure. But as soon as it tvas re- turned into the cavity of the belly, the abdominal efforts at vomiting, which had been previously ineffectual, discharged its contents. J Haller, Opera Minora, vol. i. p. 389. ; Schwartz, in Haller’s Disp. Anat. vol. i. p. 327. ; Wepfer, Sur la Cigue aquatique, p. 253. ; the Author, Op. cit. p. 11.; Betz, Wurteraberger Corr. Blatt. Bd. xx. pp. 145. et seq. § Rudbeck, quoted by Morgenbesser in Haller’s Disputationes Anatomica;, vol. i. p. 293. ; IVepfer, Op. cit. 251. and elsewhere ; Schwartz, loc. cit. Kud- beck describes it as a contraction, which began at the pylorus, and was followed by a systole of the rvhole organ, from the lorver to the upper orifice. While, according to Wepfer, it commenced in the duodenum, and passed hence towards the pylorus and the mid- dle of the stomach. II See remarks on the gastric movements, p. 312. ^ Although unable to quote exactly, 1 believe Magendie somewhere alludes to his own results as confirmed by the vivisection of about two hundred animals. 318 STOMACH AND INTESTINE. by, a contraction of the muscular coat of the stomach itself. But there is no sufficient reason for supposing that an anti-peristalsis ever obtains, far less for imagining that it constitutes a special element of this expulsive process. We may, perhaps, find some corroboration of this statement in the circumstances which constitute, so to speak, the juvantia and ladentia of this complex act. Perhaps the easiest varietj' of vomiting is that which fre- quently occurs in the sucking child. Here it is probable that three conditions, each of which might have some influence iu facilitating the return of food, are all present at once : — namely, a distended stomach, an active gas- tric movement, and the peculiar form of de- glutition which continuous sucking would imply.* The first of these three circumstances would mainly act by affording a greater re- sistance to the abdominal pressure; which although probably reduced to a minimum, is no doubt necessary to the process. And the second may perhaps constitute one of the chief occasions of this regurgitation, by impelling the contents of the stomach through the cardiac orifice. While the latter aperture might be thrown open by some slight anti accidental-]- irregularity in the act of degluti- tion. These conjectures are strengthened by the observation, that distention of the stomach, from any cause whatever, appears greatly to facilitate the occurrence of vomiting. That experience of this act, which a sea-voyage affords, may suffice to recall to most readers how much more easily the process goes on in a moderately full stomach than in an empty one. It is for the same reason that copious draughts of water are used to assist the action of emetics. And during the vomiting of both ManJ and animals^, the stomach is often gradually distended with air by a series of involuntary “ retchings,” which thus probably afford a similar assistance to the process. || In like manner, it is to that distention of the whole belly which intestinal obstruction pro- duces, that we must ascribe the peculiarly easy character of the vomiting that is then set up. The easy vomiting which occurs in cases of pyrosis may be similarly explained. In addition to these mechanical elements of the process of vomiting, there are others which, though less constant, must not be overlooked. * Schultz and Salbach (Valentin’s Lehrbuch, vol. i. p. 281.) seek to explain the vomiting of infants by the peculiar form of the stomacli at this age. But comparative anatomy entitles -us to doubt whether the mere absence of a cardiac pouch would imply such a result. And I believe that their de- scription somewhat exaggerates this peculiarity. For the stomach of the mature foetus often has a cardiac extremity not much less projecting than that of the adult. t Compare Beaumont, p. G2. j Ldpine, loc. cit. § Magendie, loc. cit. II This so-called deglutition of air has a close re- semblance to that which precedes voluntary eructa- tion. Its chief conditions seem to be, a spasmodic action of the cesophagus, and a patulous cardia. For not only do they take a frequent share in the phenomena of this act, but they also remarkably indicate its co-ordinate nature and arrangement. Thus the act is generally ushered in by a feeling of indistinct uneasiness, distention, or even pain, in the gastric region ; which is often attended by an increased secre- tion of saliva, and a loathing of food, that is soon heightened into positive nausea. This is shortly followed by giddiness, dimness of sight, and languor ; — symptoms which are evidently of cerebral origin. Next occur the retchings, or ehbrts at vomiting, before alluded to; which are probably irregular movements of the oesophagus, unaccompanied by abdominal pressure. Where the stomach is but little distended with fluid, these movements often seem to favour the subsequent occurrence of vomiting, by filling the organ with air. Finally, an uncontrollable effort so far re- verses the ordinary action of the muscles of respiration, as to bring into one period con- tractions which usually occupy different and alternate times. An energetic closure of the glottis follows the descent of the diaphragm ; so that this muscular septum is fixed by the distention of the thorax, as well as by the contraction of its own fibres. And the abdominal muscles now contract violently upon the stomach. During each actual effort of vomiting, the compression which is ex- ercised by the muscles of the trunk causes the head to become greatly congested ; so that the features are red and swollen, and the large veins of the face and temples visibly dilated. The pulse is also quickened ; and the skin often rises in temperature, and per- spires. The expulsion of the contents of the stomach from its cavity is sometimes attended by great pain, which is referred to the lower part of the oesophagus. And in spite of what is apparently a tolerable (though reversed) imitation of the movements of deglutition, a good deal of liquid generally eludes the curtain of the soft palate, and gushes through the respiratory channel formed by the nasal fossae and nostrils. The subsequent pheno- mena mainly depend on the origin of the vomiting. Where, as is often the case, its immediate cause is removed by the expulsive act itself, the patient soon recovers his normal condition. A proper consideration of the various causes of vomiting would belong rather to a medical than to a physiological treatise. We need but point out that they may all be divided into two classes; — (1) those in which there is an irritation of the nervous centre it- self ; and (2) those in which an irritation, applied to the nervous periphery, is trans- mitted thence to the centre, from whence it is reflected into the various organs which con- stitute the agents of the expulsive process. As examples of the first class, we may adduce the frequent instances in which vomiting ac- companies a cerebral injury * or disease. As * To such centric irritations might also be referred that kind of vomiting which sometimes results from 319 STOMACH AND INTESTINE. instances of the second, we might adduce, not only that ordinary form of vomiting which is brought about by a direct irritation of the stomach itself, but those numerous cases in which it follows the application of various stimuli to similar or different parts. Such are mechanical irritations of the soft palate, intes- tines, or peritoneum ; disgusting smells, sights, or sounds ; prolonged immersion in cold water; or even wounds of the extremities. The path by which these several kinds of peripheral irritation reach the nervous centre probably varies in different cases. Where they are mechanical, it is obvious that they are con- ducted to the central organ by the afferent or sensitive nerves upon which they impinge. Thus, as regards the stomach itself, irritation or section of the pneumogastric or splanchnic nerve often produces vomiting. But some emetic substances, such as antimony*, are equally active when introduced into the blood. And Magendie’s experiment f shows that — whether the poisoned current of this fluid ge- nerally exerts a local action upon the stomach or not — it is to its influence upon the ner- vous centres that the act of vomiting must mainly be referred. The various constituent phenomena of the process sufficiently indicate the medulla oblongata as that segment of the cerebro-spinal centre in which the reflection towards the periphery occurs. But the en- suing movement is by no means a simple reflex action. On the contrary, the number of organs linked together to produce it, and the alteration in them ordinary time.s, modes, and degrees of activity which they exhibit, render the whole process so complex, so truly co- ordinate, that, far from limiting our attention to the mere reflex course which its exciting cause sometimes takes, we ought rather to regard vomiting as an involuntary or physical nervous action of the highest order. The sensations that have been noticed as accom- panying it seem probably due to the cogni- zance taken by different organs, of changes which are perhaps themselves motor. At any rate, we are hardly justified in classify- ing them along with the “ reflex sensations” sometimes met with in disease. In some instances, a curious variety of the process of vomiting seems to return different purely mental emotion, and which is tj^jified in the exaggerated phrase of “ being sick ” of any thing or topic. * With respect to the vomiting produced by tar- tar-emetic, the author has made an observation which tends to show that, w'hatever the mechanical share taken by the stomach itself in the act, this organ does, in some instances, effect such a local secretion of the emetic from the blood into the gastric cavity, as may tend to remove the drug from the system. On injecting a solution of tartar-emetic into the superficial femoral vein of a dog, the mi- neral was found ten minutes afterwards in the fluid contents of the animal’s (digesting) stomach, in a state of concentration much exceeding that in which it must have been mixed with the mass of the blood. And there seem to be reasons for conjecturing that a similar local secretion occurs in the case of the salts of some other metals ; and, probably, of ipecacuan. t Quoted at p. 317. parts of the gastric contents at different inter- vals of time ; — the expulsion of more fluid and digested portions being followed, after the lapse of a considerable period, by that of crude and undigested masses of food. A small number of such cases perhaps depend on a peculiar hour-glass shape of the organ, aided by a casual constriction due to its muscular coat: — conditions which might unite to iso- late a part of the contents of the organ for a longer or shorter period. But most of them might probably be explained by the weight, bulk, and situation of the alimentary masses in the organ ; and by the other mechanical circumstances which favour or impede the act of vomiting itself. The last efforts of a prolonged vomiting often bring up a quantity of bile. But from what has already been stated, it is evident, that during the intervals of energetic vo- miting, a portion of the duodenal contents may easily find their way into the stomach, and be subsequently expelled thence. In- deed, it may be doubted whether the pylorus is completely occluded at the moment of the expulsive act : — especially in those cases in which the intestines are themselves distended with fluids exposed to the same violent pres- sure as the contents of the gastric cavity. Rumination. — There are certain individuals who are capable of returning, at will, a greater or smaller portion of the contents of the di- gesting stomach into the cavity of the mouth. This act has received the name of rumination, from its analogy to the ruminant process which forms a stage in the normal digestion of some animals. Like the latter, it is a vo- luntary return of the undigested food, wdiich is often followed by a re-mastication of its more solid portions. Apart from its voluntary character, it might be regarded in either of two points of view : — as a more complete form of regurgitation ; or as a peculiar variety of vomiting, akin to that seen in infants, and, like it, especially distinguished by the absence of nausea and of constitutional disturbance. The mechanism of the process appears to be precisely what these analogies would imply. A very deep inspiration is followed by a vo- luntary contraction of the abdominal muscles ; and, after a moment during which the trunk is kept motionless, the food rises into the mouth.* From hence, after more or less mas- tication, it is again sw’allowed in the ordinary way. The abdominal contraction sometimes requires to be aided by manual pressure in the gastric region. The date and duration of the act, as well as the frequency with which it is repeated, vary greatly in different cases. The precise share taken by the stomach itself in this rumination seems just as ob- scure— and is probably as variable — as that by which it assists in the act of vomiting. In many instances an examination of the organ after death has shown no peculiarity of * Magendie’s Physiofogie, tonieii. p. 152. 320 STOMACH AND INTESTINE. its muscular coats * ; in others, the oesophagus has been fouiul greatly thickened ; and in others f, this tliickening has also implicated the stomach itself. In other cases J, this organ has been found with a narrowed or hardened pyloric sac, or a dilated and relaxed cardiac extremity or aperture ; or even in a state of suppuration. From a com[)arison of these appearances, it would therefore seem, that the act is often at least assisted by vigorous gas- tric movements. And the existence of such movements is also implied by the fact, that this rumination occurs at the period of diges- tion, when the organ is distended, and its pyloric aperture shut. As regartls the main feature of the process — namely, its subjection to the will, — it is im- portant to notice that great variations obtain. Thus, in some of these cases, the expulsion of the food has required a violent effort. In the majority, it has been easily evoked or suppressed. While iu others, it has been al- most uncontrollable ; or its non-occurrence at the habitual time has been followed by a painful feeling of fulness, or by the act of vo- miting. On the whole, the variable condition of the stomach itself the slow acquisition of the habit in some subjects, its close resemblance to the easy vomiting of young children, as well as its analogy to voluntary eructation — all these circumstances favour the belief that the unusual effort of volition which forms the main feature of the act has for its object to open or relax the cardiac orifice and the lower part of the oesophagus. Without such a re- laxation, any further efforts on the part of the active pyloric sac would be inefficient : while, with it, their place might be more than supplied by the presence of powerful abdo- minal contractions. Finally, it is much more consistent with all we know of these two seg- ments of the alimentary canal to suppose the oesophagus capable of being slightly affected by a voluntary effort, than to imagine any part of the stomach placed in the anoma- lous position of a powerful voluntary muscle, its muscular coat sometimes remaining un- affected, sometimes being positively disor- ganized by structural disease. And the hy- pertrophy of the gastric coats, in some of the instances before alluded to, may be in- terpreted as the effect of rumination, quite as much as its cause ; in other words, as being possibly produced by that prolonged gastric movement which would result from such an act, in those instances in which the organ was otherwise healthy. Mucous viembrane, — The mucous mem- brane, on which the functions of the various parts of the intestinal canal essentially depend, is so modified in the stomach, as to offer a complex arrangement, such as remarkably * Voigtel. Path. Anat. vol. ii. p. 517. I Arnold’s Untersuchungen. Zurich, 1838, p. 211. ; Valentin’s Lehrbuch, vol. i. p. 273. J Arnold. Lehrbuch der Pathologischen Physio- logic, § 671. contrasts it with the simpler layer that lines the upper part of the tube.* And it is dis- tinguished from the compound membrane of the intestine by the possession of certain spe- cial structures : — namely, the proper gastric cells, or glandular epithelia, as they are some- times called. The remaining histological constituents of this mucous membrane are similar to those met with in other parts of the canal. A delicate membrane is variously involuted or moulded upon a quantity of areolar tissue. The latter texture, which is thus immediately subjacent to this “ basement ” membrane, forms the matrix of the mucous coat, and, as such, contains its vessels, nerves, and lymphatics, and connects it with the middle or muscular coat. While on its opposite side, the deli- eate limitary membrane sustains a number of minute cells, that bound the cavity of the tube. Examined by the naked eye in situ, the mucous membrane of the stomach is seen to be a tolerably firm but soft layer, of a pale pink colour, which everywhere loosely lines the interior of the muscular coat, and pro- jects from its surface in numerous wrinkled folds. These rugee chiefly occupy the cardiac half of the organ, forming convolutions which, though somewhat irregular, are mainly lon- gitudinal. They are effaced by distention of the stomach. And on putting the mucous membrane on the stretch, we may often discern that its whole internal surface is occupied by extremely minute pits or de- pressions'!-; the confluent and projecting intervals of which become so much longer as they near the pylorus, that they may almost be compared to very short and scat- tered villi. These depressions are the open- ings of the stomach-tubes or proper gastric glands. The stomach-tubes (c, a,d, fig. 246.) may be described as cylinders of basement membrane ; which are packed vertically side by side in a sparing matrix of dense areolar tissue, and are filled by a peculiar cell-growth. Below, they terminate in closed and rounded extremi- ties ((■/). Above, they expand slightly before reaching the free surffice of the membrane, where their margins finally become continuous with each other, so as to form a series of low ridges, the height and width of which vary somewhat in different parts of the stomach. The length of these tubes is, on an average, about J^th of an inch. But this estimate, which is tolerably accurate as regards the middle of the organ, may be almost doubled for the pyloric, and halved for the cardiac region, — a difference which forms the main cause of the vei’y different thickness of the mucous membrane in these two parts. * See articles Mouth, CEsophagus, and Pha- rynx. f Such details may be best verified b}^ everting andinflating a perfectlj^ fresh stomach ; and removing the adlierent mucus by pouring on it a very gentle stream of water, from a gradually increasing eleva- tion. STOMACH AND INTESTINE. 321 Their diameter is about g-ioth of an inch, but is also increased towards the pylorus. Thus their length has to their breadth a pro- Fig. 246. Stomach-tube from the middle o f the human stomach. Magnified \ if) diameters. a, wall of the tube, lined with large oval nu- cleated cells ; h, the same oval celhs isolated, and magnified 800 diameters ; c, nucleated cells of co- lumnar epithelium, occupying the upper parts of the tubes, and the intervening ridges ; d, blind ex- tremity of the tube. portion of about 10 to 1. Their form fre- quently so far deviates from that of a simple cylinder as to present slight constrictions or undulations. And occasionally they even exhibit a kind of caecal pouch or blind offset of greater or less length. These pouches usually spring from the lower extremities of the tubes, which generally have a somewhat increased diameter in their neighbourhood.^ But with these exceptions, the gastric tubes form simple, straight cylinders, which only widen where they open on the inner surface or cavity of the stomach. f * These appearances are generally more marked in the separated fragments of a specimen, or on its exposed edges and surfaces, and are certainly often absent. From this and other reasons I have long entertained the suspicion that they are chiefly due to mechanical violence. t A wddening of diameter which obviously cannot exceed the thickness of the matrix around each tube, and may therefore be easily estimated from the amount of this latter tissue seen in looking at any vertical section of the mucous membrane in situ. Supp. The limitary or basement membrane which forms these tubes precisely resembles this delicate homogeneous layer of the mucous structures generally, except perhaps in the fact of its possessing an even greater tenuit}’. It is usually seen only as a dark outline, bounding some part of a tube that happens to have been isolated entire. Rarely, however, it may be identified as a delicate, floating, and collapsed fold, which, on the addition of a dilute alkali, first swells up, and then alto- gether disappears. On the ridges which unite the tops of the tubes it is quite im- possible to separate it from the subjacent structures; — an intimate adhesion which forms a striking contrast to the ease with which we can often isolate the tubes themselves. The contents of these tubes appear to be every- where alike. In the upper fourth or fifth of their length, they contain a single layer of columnar epithelium (c,Jig. 246.). Seen as isolated cells, the particles of this epithelium have a cylin- drical shape, and enclose a very distinct nu- cleus near their attached extremity. But when we look at them in their natural situation, from the free side of the mucous membrane, we see that they are rather hexagonal prisms than cylinders; and contain nuclei, which appear to lie so near to their lower ends, as to be separated from the basement membrane by little more than by the cell-wall at this part. The remainder of the tube is occupied — and under normal* circumstances ap[)cars to be filled — by oval or somewhat angular cells {ad,andb, Jig. 246.) of considerable size. The largest of these oval cells are about oi" an inch in diameter. They have a more or less distinct membranous wall. The nucleus they contain is usually in contact with that side of their parietes which is attached to the base- ment membrane of the tube ; and it some- times exhibits a nucleolus. Their contents are finely granular, with here and there re- fractile dots that have a close resemblance to oil globules. And the author has been able to establish the fact, that a large proportion of these cells enclose, beside the above granu- lar material, numerous (5 — 15) pale, flat, and extremely delicate cytoblasts. Whether the centre of the layer formed by these cells constitutes a distinct calibre or cavity of the tube, — or whether it is merely an in- terval occupied by granules or cytoblasts — he is unable at present to decide. As has already been hinted, the gastric mu- cous membrane is distinguished from most other parts of the body, not only by the great delicacy of its structure, but by the com- plexity of its arrangement; and above all, by the remarkable facility and rapidity with which it undergoes disorganization and de- * It is very common to find portions of the tubes quite devoid of these cells, and occupied by a gra- nular substance, with nuclei and cytoblasts in vary- ing proportion. But I believe that this appearance, which is especially frequent in the blind ends of the tubes, is generally the result of mechanical injury of the original cells. (Compare p. 324.) , Y 322 STOMACH AND INTESTINE. composition. These clianges seem to be the result, partly of putrefaction, j)artly of a self- digestive process. And since we scarcely ever have any opportunities of examining the perfectly healthy stomach of Man imme- tliately after death, we are compelled to lay unusual stress upon the structure seen in those of the higher Vertebrate animals which approach most nearly to the human conforma- tion of this organ. Among the various domestic Mammalia most accessible for such purposes, the struc- ture and habits of the Dog rentier its sto- mach, in many respects, one of the best we can select for examination. In this animal, the tubes of the cardiac extremity (u. Jig. 248.) begin on the free or Fig. 247. Mucous memhrane from the middle of the Dog's stomach, as seen from the free surface. Magnified 150 diameters. a, ridges which intervene between the primary tubes, covered by columnar epithelium; b, primary tubes, lined by sinular columnar cells ; c, secondary tubes, given off from the preceding, and lined, at their commencement, by similar cells ; d, central calibre, or cavity, of a secondary tube. cavitary surface of the organ, by apertures which form the intervals of a kind of net- work of ridges. These apertures are polygonal, or irregularly six-sided, and the tube into which each soon merges has a diameter that is very little less than the distance between the ridges ; — on an average about Tj^j-th of an inch. The tube now proceeds down- wards for a short distance, before bifur- cating into two smaller tubes. And each of these again divides at a further stage of its descent. In this manner, what was at first a single large cylinder, ends as a bundle of about four or five small tubes, which are col- lectively enclosed in a portion of matrix thicker than that occupying their interstices. At the pyloric extremity of the organ, the tubes (a,j?w. 248.) commence by apertures, which have a diameter twice as great as those seen in the cardiac region, and from hence they pass vertically downwards for sonic distance, with a simple cylindrical form. All the ter- minal branches of these long pyloric tubes are for the most part given off at nearly the same height, so that they constitute only one-sixth, or thereabouts, of the whole thick- ness of the mucous membrane, instead of about five-sixths, as in the cardiac extremity. In both the above regions, however, the num- ber of these terminal tubes is rarely less than three, or more than six. Their diameter is generally about one-third that of the larger and simple tube from which they originate. And the total bulk of the bundle which they form, as seen on transverse section, is as nearly as possible equal to that of the primary tube. But these differences in the width and ramification of the cariliac and pyloric tubes are accompanied by a much more remarkable and important contrast in the form, size, and arrangement of their respective contents. The whole of the jiyloric tube {^s.,fig. 248.) is occupied by a single layer of columnar epi- thelium, the cylindrical or slightly |)rismatic cells of which are placed vertically to the basement membrane, and contain a very dis- tinct nucleus near their attached extremity'. The only difference offered by these cells 'in the terminal branches of the tube is, that they are shorter in proportion to their wiilth, and enclose darker and more granular contents. Fig. 248. 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 KoclUhcr. A. pyloric tube ; a, primary tube ; h, three second- ary tubes. B. cardiac tube ; a, primary tube lined by columnar epithelium; i, two secondary tubes; c, four terminal branches containing large oval cells. 323 STOMACH AND INTESTINE. They everywhere bound a tube with a dis- tinct calibre. In tlie cardiac region, it is only the ndges, and the upper part of the tubes, which are covered by columnar epithelium. At the first (b 6,/g. 24'8.) or second bifurcation of the primary tube, the character ol 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. Jig. 248.). 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 tliey generally bulge the basement membrane of the tube, so as to give it a somewhat moni- liforra outline. A closer examination shows this appearance to be caused by the prominent cells occu|)\ing 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 that in the higher part of the tubule, near where it opens into the ])rimary 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 dutinct 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, pale, 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 (A,y%. 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). Below, 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 irregular'y. 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,)%. 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. aj'ter Koelliker.') A. portion from the middle of such a cardiac tube j a, limitary membrane of tube ; b, large oval gastric cell ; c, smaller axial cells. B. Same seen in transverse section ; a, &, 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 b. Jig. 246.). The number of these cytoblasts ap- pears to vary from two to twenty in different cells. They are excessively delicate, of about ^j^jyth inch diameter : their shape is a flat- tened oval ; and they contain a bright spot or nucleus. They seem to be chiefly in contact witii 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 STOMACH AND INTESTINE. 32-I Fiipiil enclosmose of water. But they are very (juickly dissolved or burst, by contact with most of the fluids which are generally used in preparing such specimens for microscopie examination. During the five years that I have made the stomach an object of frequent (though inter- ru|)ted) research, I have examined numerous s|)ecimens 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, Babbit, 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 ramily. As resj)ects 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 anin)als 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 caixliac 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 ( FtdroDiyzun fhiviatile) no tubes are present. Finally, wliile there are many species in which the gastric structures appear to be softer anrl 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 jreriods. 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 producetl 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 adiled 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 oft’ 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, wherethcy 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 appenderl to some of the ordinary tubes, which it thus doubled in diameter. But the arrangement of these latter rlilatations,as well as the condition of the remainder of the specimens, left melittle doubt that they were due to accidental violence, which had distended the terminal branches of a tube with a large portion of its dis[)laced 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. J 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. ap. 18.52. p. 244.). Compare Bischoff (in Mueller’s Ar- chiv. 1838. p. 503.) f Bischotij 0/>. cit. p. 610. j Id. op. ; also Wasmanii (DePigestioneNonmilla. Berlin. 1830. p. 8.), and Koelliker, Op. cit. p. 150. STOMACH AND INTESTINE. 323 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 dilFerent 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 j)laced ; — the former being characterized, iio.t 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- poi’tant discover3’, 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 glandulis Brunnianis. Vratisl : 1846. tremities of the lubes. 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 throwm into folds by the contraction of the muscular tunic. It 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 2>ortcE, which rami- fies in the liver. The arteiies 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 a 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, lie-patic, and s}Aenic. Fig. 250. a, arteria covonaria ventriculi ; 6, gastric branches of the same ; c, arteria hepatica ; d, arteria gastro- duodenalis; e, arteria gastro-epiploica dextra; ff, arteria pylorica ; A, arteria splenica ; f, arteria gastro- epiploica sinistra. The arteria coronaria ventriculi {a. Jigs. 250, 251 .), or proper gasfi-ic 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. omentum ; 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-hepatic 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 brandies; 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 (eso- phageal and the gastric. The first are given off from the highest point of the vessel, or where it entei's the gastro-spleiiic omentum. They run upwards to the cesojihagus, and take a longitudinal course ; so as to [lass, wdth 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 {h,fig. 250.) run down- wards from tlie 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, wdth the gastro-epiploic branches ; and at the p}lorus, with the superior pyloric artery. 'The.arteria hepatica (c, ;?g.5. 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- lieiiatic 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 cadiac axis, as seen t:y raising the stomach, so as to e.rpose the arterial brandies behind it. a, arteria coronaria ventriculi ; c, artcria hepatica ; d, arteria gastro-duodenalis ; e, arteria gastro-epi- I'loica dextra ; f, arteria pancreatico-duoifenalis ; g, arteria pylorica ; h, arteria .splenica ; i, arteria gastro- e^iiploica sinistra. 'Yhe gastro-duodenalis ('f,7%i.250,251.) is the first and largest artery of these two. It leaves the hepatic vessel behind theduodenum, 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 gaslro-cpiploic, and a small pancrea- tico-duodcnal branch. lH[\e gastro-cpiploica de.vtra (c,y?g,s.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 desccnil from the stomach to form the “ epi- jdoon ” or apron-1 ike 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 toi'tuous direction. In this course, it gives off branches which pass upwards on both surfaces of the organ ; as w’ell 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- s|)onding branch, of smaller size, from the splenic artery. The jmna'eatico-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 w'ith 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. Jigs. 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 hefiatic arteiy opposite to the upper border of the duoilenum. More rarely it is derived from the commencement of its gastro- duodenal branch. In either case, it enters betvveen 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 froiii the cardiac extremity of the organ. It gives off numerous branches to both surfaces of the organ. The arteria splenica (h, figs. 250, 251.), or second branch of the cmliac 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 oft’ a left gaslro-einploic arterj' ; and STOMACH AND INTESTINE, 327 numerous small and short vessels, the vasa brcvia. 'Yhe gastro-epiploica shustra {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 gastro-epiploic arteries. The veins of the stomach are the superior pyloric, and the right and left gastro-epiploic. The vc7ia 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, fig. 281.) near its ter- mination in the liver. In other instances, it bends down to join the splenic vein. The vena gasiro-epiploica dextra corre- sponds to its artei‘3' in the greater part of its distribution. It usually ends by emptying itself into the superior mesenteric vein, just before this forms the vena portae by joining with the splenic vein {e, fig. 281.). The vena gastro-epiploica sinistra also runs with its artery, and joins either the splenic vein, or one of its primary brandies. 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 nnmerous 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 he, it becomes interesting to inquire what peculiari- ties of the circulation may be presumed to be con- nected ivith 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, Volkmann’s researches have shown that the anas- tomosis of channels diminishes the resistance in their interior; — a diminution which, if not met bj' 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,— w’hich have a distinctly muscular struc- ture, and are plentifull}' 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 wdth the stomach, chiefly refer to the distention of this organ. For as the stomach expands between the laminae of peritoneum, it graduall}' 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 tw'o broad and somewhat flattened networks : — one, which is composed of small arteries, anti 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 TsVofh to 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 o f the vessels o f the tmicous membrane o f the stomach, as they woidd be seen in a vertical section. a, arteries from the plexus occupying the sub- mucous areolar tissue ; b, superficial plexus of capil- laries occupying the ridges of the mucous mem- brane; c, veins passing dowmwards between the gastric'tubes ; d, capillaries between and around the tubes; e, plexus of arteries and veins occupying the submucous 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 vityth to ■j.^(jth of an inch in size. The capillaries which compose them are, on an average, little more than -go’g^th 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 abot e diameter (or Y -I 328 STOMACH AND INTESTINE, of an inch), but also in its meslies being nearly twice as close (or about ^^tb to 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 n f the mucous membrane o f the human stomach, from an injected specimen. Mag- nified 70 diameters. a, ridges intervening between tlie sto mach -tubes ; h, capillaries occupying the ridges ; e, orifice of a stomach-tube. regards the form of the superficial network, it imy 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 ca[)illary 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 tlie orifices of the tubes. In tlieir 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 ‘i” inch in diameter ; and by one or two suc- cessive unions of these and their resulting larger branches, they soon attain a widtii of about :j^oth of an inch. They now pass vertically down the intervals between the tubes, to open into the flattened venous plexus which occupies the submucous 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 netw'ork appears limited to this simpler form ; especially in the cai-diac region, where the intervals of the tubes are sm; 'lor. the other, renders it probable that the velo- city of their contents exceeds that of the blood, which circulates in the ca[)illaries of many other tissues. Such a pecidiarity 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 |)erfect 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 cavit}', 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. j See ante, p. 315. § 'I'he above remarks form a key to the following historical summaiw 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, howev'er, 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 (Mem. de I’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. Carmiiiati (Untersuchungen ueber die Natur des Magensaftes, 1785) also deduced his results from substances vomited ; and found that it was cnly the acid fluid secreted after eating which possessed antiseptic and digestive powers. Several observers, however, — among whom were Viridet "a r '■j: , ■ ; J 329 STOMACH AND INTESTINE. Physical Properlies.~Vw& gastric juice is a structureless, lini|)id, ami 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- (De Prima Coctione, Geneva, 1692), Brugnatelli (Crell’s Annilen, 1787), and John Hunter (Animal CEcononi}-, 2nd ed. p. 205. 1792)— had found that the stomach contained an acid. Macquart (M^moires 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 Physiologie, 1st & 2nd ed. 1825, vol. ii. pp. 11, 12.) analyzed a fluid obtained by volun- tarv 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 (Philosophic.al Trans- actions, 1824, pt. i. p. 45.). l)r. Children confirmed this statement from the gastric fluid of a dyspeptic patient (Annals of Philosophy, 1824, vol. viii. 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 THistoire 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 Versuchen. Leipzig, 1831). In 1833-4, Beaumont’s unique case afforded specimens for three analyses ; by' Dunglison, Sillim.an (Beau- mont, Op. cit. pp. 69. et seq.), and Berzelius (An- nuaire des Sciences chemiques, p. 282.). They all essentially corroborated Prout (Annales de Cheinie, t. lix. p. 348.) ; as did Braconnot in 1835, with gastric juice from the sponged stomach of animals. Was- 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 ^^ew, Leh- mann either preceded or confirmed him (Phy'siolo- 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 fistula; 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 andBarreswil (ComptesRendus, 1844, t xix. p.l285.) made use of the same method ; but denied the accuracy ofBlondlot’s chemical results in detail, and affirmed the presence of lactic acid. Pelouze corroborated some of their statements (Comptes Rcndus, 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 rvhich this vietv 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 flstulse (Be- richte der Gesell. der Wiss. zu Leipzig. Bd. i. teristic for each of the clifTerent* 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 month 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 lOOo’O. But from the condition of thespecimen heexamined, and the mode of weighingj" he adopted, very little reliance can be placed on this state- ment. I^assaigne f 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 100.5’0, 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 D9o in the gastric juice of a dog who had been made to swallow small pieces of limestone ; and at 1‘6 in that of a horse. Berzelius gives it at D27 in the specimen sent him by Beaumont; Lassaigne at P32, and Blondlot atl’O, from the gastric fistulm of dogs ; Frerichs (appa- pp. 100. et seq.; and Op. cit. Bd. i. s. 97.). And i'rerichs about this time came to the same conclu- sion (Wagner’s Handwoerterbuch der Physiologie, 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 fistultc an impure secretion. This he did by obliterating the ducts of the larger salivary glands. And the researches tvhich Bidder and Schmidt instituted upon the gastric juice thus pro- cured seem at length to have established, that it is the hydrochloric wdiich constitutes the proper acid of the gastric juice. [In preparing the greater part of this essay for the pres.s, 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 (Physiologische Chemie, vol. iii.) recent w'ork ; in the reports given of Huebbenet’s Dissertation by Scherer and Valen- tin, in Canstatt’s Jahresbericht (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 Jlan 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. ■j Beaumont, Op. cit. p. 72. j Loc. cit. pp. 183. et seq. 330 STOMACH AND INTESTINE. rently from tleacl animals) at E72, 1'80, 1'15, after feeding vvitli hay, hones, and pej)percorns respectively; Lehmann at an avei'age of 1’4 ; Bidder and Sclnnidt 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 L385 from a sheep. These latter higli niimhers indicate that, whatever may be the influence of an admixture of food or saliva in increasing the resitluum 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 ]003'3, — an estimate that tolerably agrees with the observationsof Lassaigueand Silliman. The quantiti/ 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 th of the weight of the whole body ])er hour, with a maximum of J^yth in the same |5eriod. 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 com[>osition 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 regartled 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 wall 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 view's of sufficient importance to demand * This calculation is founded on a method sug- gested by Schmidt, and quoted by Lehmann (O/). cit. Ikl. iii. pp. 4, 5, G.). 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 2G'938 grains of residuum would take the space of 23-617 grains of water; whence 1000—23-617 + 26-938= 1003-3. -)- In a person of average weight, the above pro- portion of ^'jth of the w'hole body would corresiioml 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 wc select son)e important details, wdiich 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 iqion chalk, and contains no chloride of calcium. He also states (or rather implies) that biidiosphate of lime is decomposed by incineration, so as to leave a neutral residue. Each of these statements is met by Lassaigne, Huencfeld, Melsens, Dumas, Bernard, and various other authorities, with a direct denial. And in a more recent Memoir, Blondlot himself lays especial stress u|)on the presence of a large quantity of chloride of cal- cium, the absence of w Inch salt he liad previously insisted on.J After these remarks, it is un- necessary to detain the reader by any further consideration of the various other errors — qualitative as w-el! 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 ])hysio- logy of digestion. Of the tw'o 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 decitle in favour of either: and those who could not suspend their judgment, w'cre 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 umnixed with food. While against the analyses ofProut§, Dimglison, Bracounot, Tiedemann, and others — in which hydrochloric acid was either lost from the * The formula of -which is CaO, 2 HO, 0^. -j- Lnc. cit. j Compare Op. cit. pp. 246. 260., and Comptes Eeiulus, t. xxxiii. p. 118. § This allusion to Dr. Prout’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 tvas 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 -svater, and tested with nitrate of silver for hydrochloric acid. It was presumed that the first method -would give the amount of fixed chlorides present ; the second, the total amount of 331 STOMACH AND INTESTINE. resitliuini, 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 j)eroxide 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 j^Tjth 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 ex|)ressly 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- hydrochloric acid, as well free as combined. The third method w'ould 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 h3'drochloric 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, such as sulphates and phosphates, were onlj‘ found in verj' small quantitj-. * Aided and confirmed b}' the observations of Blondlot {Loc. cit.), Huenefeld (Chemismus in der Thierischen Organization, Leipzig, 1840, p. 207. et seq.), and others. t VVith the “ astonishing quantitj' ” of chloride of silver obtained from the distilled liquid bj’ Dun- glison, there ought to have been at least half as much lactic acid in the (apparently uninjured) re- siduum. J Compare Op. cit. vol. i. p. 98. and vol. ii. p. 43. tallied, 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 the 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 efl'ects 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 J 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 * Lebmann (vol. i. p. 97.) urges against this ob- server, that, in a previous anah’sis, 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 inquir}’, 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. Sails. — As regards the salts of the gastric juice, we can only refer to the accurate anal3'ses alluded to above; — which, while they confirm the large quantity of chlorirles 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 exfiect. 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 Sanquinis. .Tiiice. Water - 903- 973-2 Animal matters - 88-5 17-0 Mineral substances 8-G 9-8 Chlorine - 3-6 5-6 Sodium - 3-3 12 Potassium (in dog, '2?) '3 •6 I’hospboric acid •2 •6 Phosphate of lime ■3 1-2 IMiosphate of magnesia *2 •2 (Lime corre.spondin g to ■G24 Ga. 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 StoftVechsel) has come into my hands. From it I may translate the fol- lowing paragraph (p. 44 ) ; “ The result of eighteen corresponding analyses w.as, that pure gastric juice of carnivora, after eighteen to twenty hours’ fasting, contained _/ree hydrochloric acid only, without a trace of lactic or any' other organic acid : while the gastric juice of herbivora contains, with free hyxlrochloric acid, small quantities of lactic acid ; which may, however, be referred to their more amylaceous food.” t 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 pho.sphoric acid, and neutral phosphate. sanguinis. While the amount ofits 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 stifficient to refer it to the chloride of sodium, which is the most plentiful chloiide 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 precijiitate ; 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 [iresent, 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 j-, of the extract of Pig’s stomach ; and one by Bidder and SchmidtJ of the pepsine obtained from pure gastric juice. They are as follows : — Pepsine. Vogel. Schmidt. Carbon - 57-72 53-0 Ilydrogen 5-57 G-7 Kitrogen Oxygen;( + other ele- 21-09 17-8 ments, and loss) IG-OG 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 m.'iny an.ilogies to an electrolysis. Bat, 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. 1G8. ; Ann. der Pharraacie, 1839, Apr. p. 3G. J Op.cit. p. 4G. 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 preci[)itate 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 pcpsine concoctio) : — a name to which there can be no objection, so long as its meaning is confined within proper limits ; and is not extended to imply a single and definite organic com- pound, capable of digesting all the aliment- ary principles.* The chemical properties of pepsine offer a striking resemblance to those of many albu- minous compounds. Its chief differences from these substances seem to consist in the fact, that it is little or not at all precipitated from its watery solution, by some of the salts which would throw down dissolved albumen. But the precise degree of this resemblance has been found to vary greatly in different obser- vations. Nor is this want of uniformity sur- pizing. For, as Frerichs has pointed outj-, the various watery extracts of stomach made * Here, again, the author thinks it better to sub- join in a foot-note the successive additions to our knowledge that have gradually built up the brief statement of the text, — to which many readers will probably prefer limiting their attention. As before mentioned, Keaumur, Spallanzani, and Carminati, may be regarded as having collectively determined that the gastric juice is an acid, anti- septic liquid, secreted on the introduction of food, and capable of dissolving certain alimentary sub- stances, even « hen removed from the body. The lirst attempt to analyze the organic matters of the gastric juice was made by Tiedemann and Gmelin (Loc.cit.). They announced the presence of mucus; an alcoholic extract or osmazome; and a substance, soluble in water and precipitated by various metallic salts, which they stated to be PUja- line. Eberle (Physiologie der Verdauung, Wuerzburg, 183T) adopted a more synthetical method of inquiry. He found that the addition of dilute acids to an in- fusion of the gastric mucous membraneformed an ar- tificial digestive fluid. Schwann (Mueller’s Archiv. 1836. pp. 70. et seq., 90. et seq. : and PoggendorlPs Annalen, Bd. xxxviii. p. 358.) went still further. He found that it was only the glandular part of the stomach which possessed this power. And by pre- viously removing the albumen of a gastric infusion, and neutralizing its acid, he was enabled to preci- pitate with bichloride of mercury a substance, which, when mixed with very dilute hydrochloric acid, and freed from this metal, formed a powerful digestive agent. He therefore named it Pepsine. Wasmann {Lnc. cit.) adopted a different method. He precipitated a very carefully prepared watery extract of stomach with aceta’e of lead or bichloride of mercury. After removing the metal and acid, he threw down the pepsine by' alcohol, and thus puii- fiedit from osmazome, which is soluble in this liquid. The various observers who have since corrobo- rated Wasmann’s statements do not seem to have ef- fected any important improvement in this process. Amorgst these w'e may enumerate Pappenheim (Zur Kenntniss der Verdauung, Breslau, 1839), Valentin (Repertorium, B. i., s. 64.), Elsaesser (Magenerwei- chuiig der Saueglinge, Stuttgart, 1846), Buchheim (De Albumine, Pepsino, et Muco. Lipsiai, 1845), Vogel (Op. cit.), Lehmann (Loc. cit.), Scherer, Stannius, and many others. t Op. cit. p. 780. use of in such experiments have all been mix- tures of gastric juice with a variable quantity of albuminous matters, from which substances the pep.sine is but partially set free by the sub- sequent process of purification. To tliis fact we may add, that it is not impossible the quantity and quality of the mineral constitu- ents contained in these impurities have also affected the results. Frerichs therefore exa- mined a quantity of the gastric secretion, which had been obtained from fistulae ; and from dogs who had been made to swallow in- digestible substances, such as pebbles and peppercorns. In such cases saliva would pro- bably form the only impurity. The reactions of gastric juice, and probably of pure pepsine, are as follows : it is not preci- pitated by boiling, by ferro-cyanide of [)utas- sium, sulphate of copper, alum, chloride of iron, or mineral acids. It is precipitated, though not com[)letely, by bi-chloride of mercury. Car- bonates of the alkalies give a precipitate of its lime salts. And the soluble salts of silver and lead throw down the chlorides of these metals. In all of these instances a portion of the pep- sine is carried down with the precipitate. In the case of the lead, the greater part of the pepsine is thus deposited ; but almost all of it may be recovered by washing. Action of the gastric juice. — It is to the repeated and careful experiments on artificial digestion, which were begun by Eberle, and continued by the various observers before alluded to*, that our knowledge of the details of stomach-digestion is chiefly due. This method of inquiry has not only allow’ed a continuous and close inspection of changes which must have escaped observation in the living body, but has so varied the several conditions of the solvent process, as almost to acquaint us with the share which each takes in the final and united result. In short, these “questionings of nature” have so far been answered, that we may be said to know, not only what substances the stomach digests, but by what means it digests them. Of the nature of this process, however, we are still ignorant ; or at most, can only find in its cir- cumstances some analogies, such as may justify and support a few vague conjectures respecting it. Temperature exercises an important in- fluence on the gastric solvent. At the or- dinary temperature of the atmosphere, the action of the gastric juice is scarcely percep- tible, even when continued during many hours. f Lower degrees of cold suspend its action still more completely. Heated to the temperature of the body — namely, to about 100° Fahrenheit — it acts very energetically. A further accession of temperature at first increases, but soon injures, and finally for ever destroys, all its digestive powers. The precise point at which this change of effect occurs is not clearly known; but it is probably at or near 120°. The dried pepsine of the artificial digest- * In the foot-note to this page. t Beaumont, Op. cit. p. 146. 334 STOMACH AND INTESTINE. ive fluid will, however, sustain a temperature of 160° without damage. But at a lieat above this, it becomes wholly inactive, and partially insoluble. And Dunglison* found the organic principle of the gastric juice to be insoluble in hot water. Alcohol, acids, and alkalies, when applied in excess, have also a destructive influence on the digestive power of pepsine. In the case of acitls, this injurious effect is much less marked. As might have been ex- pected from the constant reaction of the gas- tric juice, an acid is essential to its digestive efficacy ; — indeed, we might almost say, to its very existence. Even that incom|)lete loss of acid, which we have seen to be involved in the precipitation of its pepsine, must be compen- sated by an artificial acidulatiou, before the aijueous solution of this substance regains its foiiner digestive powers. Here, however, as in the case of heat, it is necessary that certain limits shoukl be obser- ved. Wasmann found that an addition of about 3 parts of hyilrochloric acid per 1000 formed a tolerably effective fluid: — a (juan- tity which corresponds with about half of that present in the gastric juice according to Bidder and Schmidt’s analyses. j- But much larger |jroportions of this acid may be added, not only with impunity, but even with advantage. Thus Schwann used from 6 to 12 parts [)er 1000. And Elsaesser thinks that the most favourable proportion for diges- tive purposes is about 3 or 4 [ler cent, of muriatic acid ; — a quantity which would be about five times as great as that present in the gastric juice. But the nature of the acid seems a matter of inditterence. J Nitric, phosphoric, sidphu- ric, acetic, and lactic acid, have all been suc- cessfully made use of. And the rangeof amount already spccifieil for hydrochloric acid might, d priori, [uepare us for the fact, that the re- quisite quantities of each of these acids seem solely related to their more or less dilute state; and do not allow us to recognize any trace of an equivalent chemical pro|)ortion. Applied in still larger quantities, all of these acids first weaken, and then destroy, the digestive power of the solution of pepsine. The comparative amount of injury inflicted by equal quantities of the different acids appears to depend, like their solvent efficacy, chiefly on the degree of their concentration, and that of the digestive fluid itself. How essential its acid is to the solvent powers of a natural or artificial gastric juice, is well shown by the effect of neutralizing it with an alkali. Under these circumstances, not oidy does it lose all action upon albu- minous substances, but if mixed with them, soon shares in the putrefaction which they are liable to undergo. An equally rapid putre- faction occurs in the simple aqueous infusion * Beaumont, Op. cit. p. 69. t The acid Wasmann added to the pepsinous fluid being liquid, would contain less than half its weight of true hydrochloric acid. I Bernard, Loc. cit. ; Lehmann, vol. if. p. 50. of stomach. Left to itself, however, the powers of the neutralized gastric juice are only suspended ; and can be restored by the addi- tion of a proper quantity of acid. But in the course of time, the neutral fluiil gradually becomes mouldy : — a process which appears to differ in its rapidity only from the similar decomposition that occurs in pure gastric juice, ajtparently after the slow evapora- tion of its acid.* A still larger quantity of alkali permanently destroys all its solvent powers, and is followed by its rapid putrefac- tion. That incomplete loss of acid which was noticed as occurring in the ordinary processes for obtaining pepsine, does not entirely sus- pend its specific action. On the contrary, its watery solution still retains the power of pre- cipitating large quantities of casein, and even of exerting a feeble digestive or solvent influ- ence. But while all such observations on the artificial digestive fluid agree in representing an acid as one of its most essential elements, some physiologists have gone further, and have asserted it to be so far the true and only prin- ciple of the gastric secretion, as to be capable of imitating its action. And others, who allow that the dilute acid is only rendered efficacious by the presence of the organic matters with which it is combined, have doubted the specific nature of the gastric prin- ciple; and have asserted that acidulated saliva or mucus, or an acidulated infusion of blad- der, diaphragm, trachea, or intestine, is ca- pable of effecting a solution of the protein com- pounds like that seen in artificial digestion. Each of these remarkable statements demands a passing notice. Many dilute acids — such as suljihuric, nitric, acetic, hydrochloric, and phosphoric — can certainly produce appearances resembling imperfect solution, in meat and many of the protein compounds. But such a solvent ac- tion, even when most marked — as in the steeping of small pieces of coagulated albu- men in dilute hydrochloric or phosphoric acid — differs greatly, both in nature and amount, from the true stomach digestion. It requires the aid of a much higher temperature ; it is ex- cessively slow, superficial, and imperfect ; and the resulting weak and turbid solution often parts with its dissolved constituents on the addition of the ordinary reagents. The same statement will apply to various experiments that have been made with an aci- dulated inl'usion of large or small intestine; in which the process of solution, though some- what -j- more energetic, is still so feeble, slow, and imperfect J, as to be scarcely comparable with that effected by the gastric juice. While we ought not to forget, that the superior * Beaumont, Op. cit. p. 71. ; BJondlot, Op. cit. p. 351. f Compare Valentin, vol. i. p. 366. ; Todd and Bowman, vol. ii. p. 203. ; and Frerichs, p. 795. J In any future ob- ervations of this kind it would be very desirable to institute a strict com- parison betw'een the reactions of the resulting solu- tion, and those of true peptone or aJbuminose. STOMACH AND INTESTINE. 335 efficacy of such infusions, and especially that of the duodenal membrane, is at least partially explained by the way in which the gastric juice is necessarily diffused, with the food, over the surface of the intestinal canal. The effect of the neutral salts on artificial digestion has scarcely been investigated with all the attention it merits. But it appears not improbable that many of these inor- ganic substances assist solution, when present in small quantities, but oppose it when added in excess. This is especially the case with chloride of sodium, the ordinary condiment of mankind and of many animals. The effect of this salt in facilitating the digestion of albu- men, fibrine, and casein, has been verified by Lehmann for the proportion of H per cent. The effect of alcohol is also regulated by its amount and concentration. Diluted, it seems to have no chemical action whatever. In larger quantities, as before remarked, it precipitates pepsine. And in still greater excess, it permanently destroys all its diges- tive energy. The way in which the process of gastric solution, whatever be its nature, is assisted by the minute division of the substances sub- mitted to it, as well as by the movements of the stomach, is too obvious to require any special mention. It only remains to add that, according to Purkinje and Pappenheim, an in- crease in the amount of the atmospheric pres- sure furthers the artificial solution of albumi- nous substances. These observers therefore regard natural digestion as somewhat "aided by the pressure of the gastric and abdominal parietes. The quantitative relations between this or- ganic principle and the proteinous substances which it dissolves, form a very important sub- ject for inquiry. An exact determination of the quantity of pepsine which these substances require for their solution, would greatly assist us in solving many problems with re- spect to the chemistry of digestion. Or con- versely, a knowledge of the exact numerical details of nutrition, and of the daily gastric secretion, would enable us to calculate the proportionate quantity of pepsine periodically required and used. But it is obvious that such calculations can only confirm direct ob- servations ; that they multiply all the known errors of their elements, and neglect their un- known ones. And the estimates derived from actual experiment are very conflicting : — if, indeed, they can be considered really compar- able. Thus that precipitation of casein, which is effected by the watery extract of stomach, is producible, according to Mit- scherlich*, by a quantity of pepsine amount- ing to jqooth of the milk made use of : while Schwann states to be required. Wasniann found that dilation of the pepsine to eooVbth did not destroy its power of dis- solving coagulated albumen. Frerichsf and * Bericht, &c. der Akademie der Wissenschaften zu Berlin, 1842, p. 147. et scq. t Op. cit. p. 794. Schwann give estimates, which (allowing for the impurity of the extract of stomach) may probably be regarded as an assertion, — that one part of pepsine will dissolve 500 of meat, or moist and finely divided albumen. With these statements may be contrasted those made by Beaumont, Blondlot, Lehmann, and Schmidt. In describing his observations con- ducted with gastric juice, Beaumont* implies that this secretion cannot take up more than 50 per cent, of roast meat. From what he says, however, as well as from some observa- tions by Blondlotf , it seems very doubtful whether even this can be regarded as a per- fect solution. And Lehmann would fix its sol- vent properties at about 2o per cent, for moist albumen. While the average and maximum power of Bidder and Schmidt’s pure gastric juice is stated by them at w'hat would be about 10 and 20 per cent, respectively for the same substance. Reducing gastric juice to pep- sine in accordance with their analysis, it would seem that one part of the organic prin- ciple cannot dissolve more than 12 of albumen. And even Beaumont’s highest estimate would but raise these 12 parts of albumen to 30 of the more digestible meat : — a quantity which is still small enough to form a striking con- trast with the larger proportion deducible from the statements of Frerichs. But it is scarcely necessary to observe, that the state of the substances used, the dilution of the fluid, and the amount of acid, will always ex- ercise a great influence on the results ; and may at least partially account for these great discrepancies. As already implied, the gastric juice is ca- pable of dissolving, not only albumen, but the protein-compounds generally, including in this term the various substances known by the names of fibrin, casein, globulin, vitellin, hcematin, &c. To these we may add gelatin, chondrin, and gluten. In the case of all these, however, their physical condition seems greatly to regulate the rate of the process : density and bulk rendering it very slow ; while, conversely, it is accelerated by minute division. Nor is it impossible that the quantities of the sol- vent required vary with the nature and aggre- gation of the particular substance. But in any case the ultimate elfect is the same — the production of a complete solution. The application of the term “ chyme,” by the older authors, to the food which had undergone stomach-digestion, sufficiently indicates that the mass possesses a comparatively uniform physical appearance. And even wffien further observation pointed out, that the chyme w’as liable to considerable variations in colour and consistence, the above opinions as to its uni- formity required but a partial modification. For physiologists then began to be aware, that the gastric change was not so much a stage in the digestion of the whole of the food, as the solution of a certain class of its * Op. cit. p. 133. t Op. cit. p. 264, 336 STOMACH AND INTESTINE. constituents. It was reserved for Miaihe* * * § to show, that the homoj;eneous physical con- stitution, which the whole contents of tlie stomach were erroneously supposed to assume at the end of its digestive act, is true in a much more important chemical sense, if limited to certain portions of the food. He found that the gastric digestion of the various protein compounds affords a solution which, what- ever the nature of the substance originally dissolved, possesses the same ])hysical and chemical properties ; — these properties being due to its containing a substance which, from its relations to albumen, he called albuminose. Lehmann f, who has confirmed and e.xtended Mialhe’s researches, proposes for this substance the better name of Peptone, — According to these observers, the following properties are common to all kinds of peptone, from whatever substances they may have been derived. Reduced to the solid form by careful evaporation, peptone is a white or yellowish-whitesubstance ; almost tasteless aiul inodorous; very solublein water; but inso- luble in alcohol of 83 per cent. Its watery solution reddens litmus; and is precipitated by chlorine, tannic acid, and metallic salts ; but is unaffected by boiling, by acids, or by alkalies. With alkalies and bases it forms very soluble neutral compounds or salts. An aqueous solution of these is still less preci- pitable by reagents than one of peptone itself. Thus it is thrown down only by tannic acid, bichloride of mercury, and a mixture of the acetates of ammonia and lead ; — the acetate of lead, and the ferrocyanide of potassium causing but a faint cloudiness; and even con- centrated acids, nitrate of silver, and alum, having no effect. The idtimate chemical composition of any particular peptone so closely resembles that of the substance from which it is formed as scarcely to require any further remark. In speaking of these chemical phenomena of stomach-digestion, there remains but to notice, that the addition of water, or a small quantity of fresh acid, is capable of re- storing some of its original digestive powers to saturated gastric juice, or a solution of peptone. The degree in which this renovation can be effected is obviously a question of great importance. But at present there are no exact observations on which to found any conjectures respecting it. It seems, however, sufficient to explain the discrepancy previously alluded to^ between the quantity of hydro- chloric acid which is present in the normal gas- tric juice, and that which is required to be * Journal de Pharmacie, t. x., pp. 161. et seq. t Op. cit. vol. ii. p. 50. J Both names being comparatively recent, there can he little objection to the adoplion of the prefer- able one. And “peptone” not only' connotes its relation to digestion, but avoids the disadvantage ot “ alhuminnse ” : — viz., that of giving an undue prominence to the connection of albumen with the gastric function. § See p. 334. added in preparing an artificial digestive fluid of maximum solvent power. The foregoing brief summary of the chief physical and chemical properties of the gastric juice, naturally leads us to the important question — What is the nature of its action? 1 . It is obvious that the phenomena of gastric digestion do not constitute a simple process of solution by a dilute acid. For the organic princi[de is essential. The substances are not merely dissolved, but exhibit altered reactions. And, finally, they are not restored to their original form by the neutralization of the acid. 2. Some have supposed that the organic principle exercises a contactive influence, like that of spongy platinum in the acetification of alcohol. 3. Others have imagined that it produces a fermentation, like that excited by yeast in a solution of sugar. But we have seen that gastric juice will not dissolve more than a certain quantity of protein-compounds. While, in both of the above processes, a small quantity of the con- tactive or fermenting substance excites an action, which continues until the whole mass has been oxidized or fermented, as the case may be. This objection appears fatal to both these theories. And as regards the latter ol them, we may further point out, that, unlike the particles of yeast, which are themselves undergoing metamorphosis, those of the di- gestive fluid are singularly stable, and enjoy a singular immunity from the putrefactive process. 4. Schmidt* has propounded a fourth theory, according to which the organic prin- ciple, and the acid, of the gastric juice are united to each other in the form of a complex acid, which he calls the hydrochloro-pejtsic. This is decomposed by heat into pepsine and hydrochloric acid. In the stomach it unites with protein-compounds as bases, to form so- luble combinations. When treated with an alkali its pepsine is precipitated. And even when saturated with a protein-compound the power of the gastric juice is restored by fresh acid; because the latter, by uniting with the base, sets free the hydrochloro-pepsic acid, and thus enables it to combine with another portion of proteinous substance. But in respect to the two latter statements, it would appear that an alkali precipitates from the gastric juice but a very small part of its pe|)sine; anil that even this portion is in com- bination with calcareous salts. While the re- actions of peptone show that the original pepsine is neither present as such, nor is ca- pable of being set free from its state of com- bination by the addition of an acid. And other facts, which seem to speak strongly in favour of this view, will as little bear a close investigation. Such are the close union of the acid to the organic principle; the definite amount of acid required for artificial digestion ; and the similarly definite amount of proteinous * Loc. cit. STOMACH AND INTESTINE. 337 substances which the gastric juice will dissolve. For the more abundant of the salts contained in the gastric juice appear to be almost as closely united to its pepsine as is the acid itself. The supposed complex acid has never been isolated; still less has its combination with the supposed base. The latter, again, does not saturate the acid, and has never yet been replaced by other bases. In like manner, the tolerably fixed proportions of acid and of protein cannot be reduced to definite equiva- lents. And, finally, while the restorative action of fresh acid cannot be fully explained, the equally marked effect produced by pure water is still more mysterious. We are thus gradually led to the conclusion, that neither of these four theories — solution, combination, contactive excitement, or trans- ferred metamorphosis — will afford an adequate explanation of that process of stomach-diges- tion, from the observed phenomena of which they all so widely differ. It is indeed scarcely to be \vondered at that we are unable to form a satisfactory theory. For it is probable we are still ignorant of many processes of organic chemistry. While it is possible that the action of the gastric juice is quite sui generis. And hence any view w'hich unites most of the circumstances of the case, will be certainly as useful, and probably as true, as one which, like each of the preceding, assumes an undue parallel for the sake of a full explanation. If we must connect the above details by some theory, we may first remark, that the gastric juice dissolves protein-compounds; that it renders them highly soluble ; and that it as- similates their form and reactions to its own, without changing their coni|)osition. For any parallel to such a process we can only look to those lower degrees of chemical action, where solution and combination, adhesion and affi- nity, maybe supposed to meet and merge into each other; where proportions are tolerably definite, but true equivalents indistinct ; and where, though form is changed and reactions modified, elementary composition remains little affected. Actions of such a kind may be found in the union of many substances w'ith water, or its elements, to form the compounds called hydrates. And the conversion of pro- tein into peptone, by the gastric juice, pre- sents so many analogies to the formation of a hydrate*, that it seems not impossible the chief office of this secretion may be, that of ena- bling water to combine with the various mem- bers of the albuminous groups of alimentary substances, in order to their acquiring that so- lubility, and uniformity of constitution, which must probably precede their admission into the current of the blood. To this vague indication of a theory, I will only add, that the mode in which a definite quantity of the organic [trin- ciple takes part in such a process cannot even be conjectured. Its action certainly appears no W'ay comparable to the effect of diastase on starch, or of emulsine on amygdaline. It seems to be an assimilation, in the strictest * Compare Dr. Prout’s treatise “ On Stomacli and Renal Diseases,” 5th edition, p. 470. et passim. Supp. chemical sense. It is not impossible that the acid commences the process by a slight, though genuine, solution of the more resist- ing substances. And at any rate, this con- stituent seems to have the power of checking putrefaction, if not of arresting all metamor- phosis, in the other ingredients of the secre- tion : — like the small quantity of oil of vitriol which is adtled by the chemist to hydrocyanic acid with the same object. Process of secretion. — The process by w hich the gastric juice is secreted from the mucous membrane of the stomach, forms one of the most interesting problems in physiological science ; and one which, if satisfactorily ex- plained, would probably throw much light on the morphology of secretion generallj'. Ever since the discovery of the stomach- tubes by Dr. Sprott Boyd, it has been generally assumed that the secretion of the gastric juice is mainly effected by a discharge of their glandular contents. The precise mode of this expulsion seems usually to have been left undecided : though it has been implied that the pressure of the muscular contractions of the organ upon the more or less solid food would almost compel an evacuation of the tubes. And more recently, Frerichs has asserted that the act of secretion is really aided by such an expulsion ; and that the food becomes enveloped in a layer of the large gastric cells, the discharge of which from the stomach-tubes leaves them collapsed and empty. To all of these statements the author ven- tures to offer a deliberate contradiction In re- searches upon this organ which have extended over some years, he has never seen these gastric cells free from the tubes except when there was good reason to attribute their ex- pulsion to mechanical violence. They are never present in large quantities. In the majority of examinations they are almost absent. With the proper use of the precau- tions previously alluded to, they will rarely or never be found. In addition to this, it may be added, that the arrangement seen in the Dog — where the stomach-tubes are lined by a continuous tube of epithelium, which is prolonged into the layer of columnar cells that occupies their intervening ridges — renders it almost impossible that these cells should be shed in their original form. Another part of this statement has already been contradicted. During every stage of gastric digestion, the tubes may be seen with precisely the same form, size, arrangement, and contents, which they exhibit during the fasting state. This remark even applies to that narrow calibre of epithelium, which is seen within the axis of the proper gastric tube in the Dog. And hence, ignorant as we are of the exact mechanical arrangement of the fibre-cells at the bottoms of the tubes, still the excessive delicacy of these secreting organs, taken in conjunction with this uni- formity of appearance, renders it highly im- probable that they are evacuated by any ex- traneous pressure. z 333 STOMACH AND INTESTINE. The anatomy of the fresh stomach also suggests other conjectures, which confirm the conclusion which we have deduced from the above sources. We have already noticed tliat, in the Dog, the columnar epi- thelium forms but a single row, and that it covers all the ridges during the digestive act. Hence the columnar cells can scarcely be stripped off in successive layers at this time. While the close attachment of each of these cells to those around it, together with their uniform ajtpearance m renders it alike im- jtrobable, either that a cell is extruded singly and then bursts, or that each, as it fills, rup- tures and collapses. All those within a tole- rably wide circuit of membrane seem absolutely similar and coeval. In some cases, however, the gastric juice does contain columnar ej)ithelia mingled with the food. In the Dog, this appearance is un- usual, and the number of such shed ceils is small. In the Rabbit, their separation is more frequent and extensive. While in the Pig, it often forms a more or less continuous layer, which is almost moulded to the ridges of the stomach and the mouths of its tubes*, and leaves the mucous membrane below denuded of this its proper covering. But it remains for future researches to show, whether this ap- pearance is due to mechanical violence; to commencing putrefaction; or to the distur- bances implied in the muscular contraction, the exsudation, and the other incidents of the act of death. And whatever the interest attaching to such a dehiscence of these columnar cells, it can scarcely have any but a very indi- rect relation to the healthy secretory pro- cess that obtains in the living man or dog, in whom the jHire gastric juice is coitipletely structureless. This fact, announced by Beau- mont, at a period when microscopy was much lass understood than at present, has since been repeatedly confirmed in observations on gastric fistidte which have been instituted by Bloudlot, Bidder, Schmidt, Iluebennet, and myself. And if great care be taken not to disturb the surface of the mucous membrane, we may often verify it in the fresh stomachs of dogs which have been killed immediately after feeding. Here again we may refer to Dr. Beau- mont’s numerous observations.f He made use of magnifying glasses, by the aid of which he could distinguish the spheroidal glandular follicles, and the papillae situated in their in- terstices. These papillae, or villi, he found to be scarcely visible until food was applied to the mucous membrane ; when they underwent a kind of erection, and protruded from its surface in the shape of small sharp processes. From these, according to this faithful observer, the gastric juice a|)pears to exsude. Its secre- tion begins by the gradual appearance of innu- merable lucid specks, which are smaller than the mucous follicles. These specks or points * Compare Koellikcr, p. 150. t Op. cit. pp. 95, 90, 128. et pasuin. rise through the transparent mucous coat: and seeming to burst, discharge themselves upon the very points of these vascular pa|)illae, as a thin, transparent, colourless, limpid, acid fluid ; which collects in small drops, and spreads over the whole gastric surface. So thoroughly persuaded was Dr. Beaumont that the fluid exsuded from the pa[)illae alone, that he had not the least doubt the excretory ducts of the follicles were enclosed in these villi, and terminated in the lucid specks just alluded to ; although he admits that he could not see any apertures here. Coinjiaring this description with w'hat we now know respecting the anatomy of the mu- cous membrane, it is difficult to avoid coming to the conclusion, that the large and nume- rous capillaries beneath its ridges are in some way intimately connected with the secretion of the gastric juice. And whether this conjecture be right or w rong, the charac- ters of this secretion corroborate the con- clusion already deduced from the anatomy of the dead stomach : — - viz. that the gas- tric juice is not composed of a shed epi- thelium. In like manner, the rapidity with which it exsudes seems to contradict any theory of even the most rapid solution of columnar* cells. And since anatomy shows that, until the end of gastric digestion, these cells, if dissolved, are immediately replaced by others, it follows, that to assume such a process of dehiscence w’ould imply a rapidity of growth and organization, such as has never yet been verified in the higher Vertebrate animals. The latter quantitative objection may be bet- ter carried out in detail. In Schmidt’s expe- riments, a dog secreted 2\>th of its weight of comparatively pure gastric juice in one hour. Transferring such an estimate to an average man of 140ll)S. weight, it would follow that the human stomach, the whole mucous membrane of which scarcely weighs 4oz.j can com- pletely reconstruct its entire cell growth, — which is, at most, only half of this weight, — about sixty times in a single hour ! As regards the source of the acid, the above statementby Dr. Beaumont is supported by an interesting obervation of Bernard j- ; who finds that it is only the surface of the mucous membrane which exhibits an acid reaction, cither in the digesting or fasting state. This statement I can confirm : al- * When freed from their attachment, these co- lumnar cells often undergo what seems to be a rapid solution in ihe surrounding fluid under the microscope. The first stage of this exhibits them as V. ry delicate husks, which appear to have emptied themselves after losing the lid of cell-wall at their larger extremities. Their .sides now often collapse: and increasing transparency .soon renders them invi- sible. This process’oeenrs so quickly as to resemble a digestive solution. But it is difficult to determine how far it is effected by the contents of tlie cell itself, apart from the surrounding fluid. A layer of iTuiens generally occupies the neighhonrhood of any cut surface of gastric mucous membrane, and ap- pears also to consist of the dissolved contents of cells. f Gazette Medicale, Mars Hi. 1844. STOMACH AXD INTESTINE. 339 though I have sometimes found below the surface a faint acidity, such as might have been due to a mere admixture or imbibition of the fluids above. But supposing Dr, Beaumont’s conclusion true — that the gastric juice exsudes chiefly from the papillary ridges that intervene be- tween the tubes — what office shall we assign to these latter structures themselves ? The occurrence of these tubes is the rule throughout the Vertebrate classes. And not only are the large cells which form their con- tents equally constant, but Goll and Koelli- ker’s* researches have shown that it is in these cells, — or at least in that part of the stomach which contains them, — that the digestive power chiefly, if not essentially, resides. Any indirect or collateral action seems insuffi- cient to explain such a close mutual associa- tion of structure and function •. — an association w’hich not only ranges a great part of organ- ized nature, but repeats itself in the organ of the individual. Hence, whatever the office of these cells, it is probably concerned with the elaboration of at least one important con- stituent of the gastric juice. It would seem that this constituent is not the acid. Shall w'C therefore conjecture it to be the organic principle ? This conjecture, which rests on foundations so slight that the author feels he has no right to propound it, except in the interrogative form in which it presents itself to his ow n mind, is perhaps more compatible with the facts at present known than any other that he can indicate. It is, however, possible, that the observa- tion of Dr. Beaumont just cited was based on some optical illusion ; — that, for instance, the lucid specks which he saw on the villi only, had in reality extended np these pro- cesses from dark and depressed openings of the tubes. But even supposing this to have been the case, the superficial acidity of the stomach may be regarded as showing, that the preparation of its secretion is only completed by the cell-growth which lines the lower [lart of the tubes. At any rate, it seems certain that the gas- tric juice is not composed of the dehiscent nucleated cells of the mucous membrane of the stomach. This fact appears so well esta- blished, that we ought not to shrink from re- ceiving it, however it may impugn what is ordinarily understood as the cell-theory. In respect to the latter doctrine, the author can only mention another view, which, though novel and plausible, he has long felt obliged to give up. After verifying the obscure cytoblasts which fill the large oval gastric cells, anti the more distinct ones which line the axis of the stomach tubef , as well as the gradual trans- * Op. cit. Bd. ii. p. 146. t It is interesting to notice the close structural analogy offered by these small axial cells to those which line the buccal and duodenal glands. The more so that the latter appear to secrete a fluid which possesses the capacity of effecting a rapid and impor- ition of these into the ordinary columnar epithelia covering the ridges, — it occurred to him that this structure, together with Bernard’s and Beaumont’s observations, were all sus- ceptible of a single explanation. According to such a view, it might be supposed that the mother-cell gradually enlarged, ruptured, and discharged its contained cytoblasts. These arranged themselves in the axis of the tube ; and urged by a gradual pressure, or by the growth of new cytoblasts below them, passed up the follicle to where the mother-cells ceased. There they became attached to the wall of the tube itself, and acquired a colum- nar form by' a gradual distention of their interior; — a distention, which increased as they approached the summit of the ridge, w'here they were finally extruded, or burst. Thus the cell which was constructed below, was filled above : — a subdivision of the secre- tory process, w'hich might be supposed to de- pend upon the solvent powers of the secre- tion being injurious, either to the production of blastema, or to the multiplication of cells. Such a view seemed more or less to account for the structure of the mother-cell; for the gradual transition of the cytoblast into a columnar cell ; for the superficial acidity, and for the vascular arrangements, of the mucous membrane. It also appeared to be con- firmed by the tendency of the columnar epithelia to cohere strongly with each other, and adhere slightly to the subjacent basement membrane. But the uniform anatomy of the ridges, and the completely structureless cha- racter of the gastric juice, were insurmountable objections, which ultimately led to the com- plete abandonment of this theory'. And as regards the whole theory of secre- tion by cells, surely it is high time to modify- it so that it might involve, not a less immediate action, but a somewhat less extravagant expen- diture, of these minute organs. For the impro- bability which we have shown to be implied in the application of this theory to the stomach, holds good in a far higher, not to say a very different sense, of many other secreting structures. Indeed in some of these, it is obvious, that their situation would involve an enormous w-aste of life and matter, sup- posing the bulk of their organic products to be really enclosed in deciduous or dehiscent cells. Amongst such we may specify the kidney, the most important duties of which are supposed to be executed by secretion into a cell-growth, from a venous surface — a cell-growth of which we may doubt whe- ther it even undergoes a rapid solution, while we can definitely predicate that it is not discharged entire, in any quantity at all com- mensurate with the large amount of solid constituents which is removed from the body in the urine. Small intestine. — The next portion of the alimentary canal is that which is included between the pyloric and ilio-caecal valves, and is named, from its diameter, the small intestine tant metamorphosis in another cltiss of organic sub- stances. (See p. 3G2.) 31:0 STOMACH AND INTESTINE. {h'At.Intcstinuvi tenue,Vr Intestin grele, Gevm. IJLienndarm). The shape of all this portion is c}linclrical. Its average length is about 20 feet ; its dia- meter about ll: inches.* But apart from those varieties in its dimensions which it presents in different individuals, the yielding nature of the tube allows it to be narrowed by artificial extension. While, vice versa, it is just as easily shortened by dilatation. And it is very difficult accurately to estimate those minor degrees of distention to which it is liable. Hence little stress can be laid upon the statement of Cruveilhier, that the small intestine tapers away from the duodenum to near its extremity, where it suddenly dilates to enter the large intestine. The small intestine occupies the cavity of the belly. Its commencement, at the [)yloric extremity of the stomach, is placed in the right hypochondriun); its termination, in the caecum that begins the large intestine, occu- pies the right iliac fossa, to which this part of the intestinal canal is fixed. The few inches of bowel immediately above this extremity frequently occupy the pelvic cavity. But almost all the intervening portion is so free to move, that each particular point of its length may be found in any part of the ab- domen or pelvis. * Trustworthy observations on this point are still to be desired. IMeckel states that the length of the whole intestine is from tliree to ten times the stature. And most authors have been content to fol- low him in estimating its average proportion as six times the height of the body. As 1 presume such a comparison of the two measurements was never in- tended to be more than an aid to the memory of the Anlhropotomist, I need scarcelj' point out its in- herent improbability, as well as the diffierdty of estaldishing a close ratio between a multiple assumed to be so high, and a multiplicand known to be so variable. Besides, differences in the dimensions of the canal are not easily' established, uniess their amount is very considerable. For the facility with which, in such a tube, length is conv'ertible into width, forms one palpable source of error, which can only be obviated by a very careful comparison of both the above measurements. The effect of a more or less complete removal of the mesentery is almost as obvious; and perhaps entitles us to suspect that all such estimates of the length of the-separated bowel represent it as somewhat greater than it would be in situ. And we are still more unable to determine that alteration of both dimensions which the simultaneous dilatation or contraction of its two muscular strata would necessarily effect. While it is only after we have either obviated, or al- lowed for, all the preceding causes of inaccuracy, that we can come to any valid conclusion respecting those differences which doubtless obtain in different individuals. The statement 1 have ventured upon in the text is based upon a number of measurements made by my- self. In making these, the healthy intestine was laid upon a board, and spread out to wbat seemed a proper avidtb, before taking its length. Their number (less than forty) is too small to justify us in regarding their average as a very valid one. They afford no information as to the effect of age or obesity. But they give what is probably a more accurate estimate than that ordinarily adopted by authors. And they agree with an average given by Cruveilhier, as well as with four cases, in which it seems not unlikely that he adopted precautions similar to those just alluded to. T/ie duodenum. — That upper part of the small intestine which is directly continuous with the stomach, is distinguished, both from this organ, and from the lower part, by certain peculiari- ties. And though these chiefly affect its exter- nal anatomy, still we shall hereafter find that they are nett unaccompanied by differences in the structure of its mucous membrane. Start- ing from the constriction before alluded to, as marking the site of the pyloric valve, the in- testinal tube forms a curve in the shape of a horse-shoe around the head of the pancreas ; Fig. 254. Shape and arrangement of the dandeman. {The stomach and liver are raised to shorn the pancreas.') St, stomach ; p>, its p3-loric valve ; I, liver ; g, gall- bladder; d, duodenum; 1, 2, 3, its first, second, and third portions; /ra, pancreas ; h, head of the pancreas, which is received into the concavity of the duodenum ; sp, spileen ; a, aorta, behind the in- ferior transverse portion of the duodenum ; sm, the superior mesenteric arterj', in front of it. receives the duct of this gland, as well as that of the liver ; and is closely fixed by perito- neum to the posterior wall of the belly. This fixed commencement of the small intestine has been named the duodenum, in consequence of its length being estimated at twelve finger- breadths {SahcKaSaKTuXov, zwoeljp.ngerdarm'). It has also been called the ventriculus succenlu- riatus, or supplementary stomach; — -a vague term, which was probably based upon an in- accurate notion of its office. Beginning at the pyloric constriction, the duodenum proceeds outwards, backwards, and a little u|)wards, to the under surface of the right lobe of the liver. It then turns down- warils, and a little inwards, in front of the right kidney ; so as often to impress a shallow fossa on the hepatic surface in front of that depression which corresponds to this organ. After a short perpendicular course, it finally makes a second bend, by which it regains a horizontal tlirection, and passes from right to left, and a little upward, in front of the vena cava, the aorta, the right crus of the diaphragm, and the vertebral column. It terminates opposite the leftside of the body of the second lumbar vertebra, at a point which corresponds to the commencement of the mesentery. Here the intestine becomes free, and is named the jejunum. The length of all this curve, when unfolded, is about ten inches. But for the sake of STOMACH AND INTESTINE. 311 greatei' exactness, the three chief portions of the duodenum may be described separately. The first portion is called tlie sujyerior transverse or hepatic. It is much the sliorter of the three, being scarcely two inches in length. It lies solely in the right hypoclion- drium ; and, near the neck of the gall-bladder, terminates by bending downwards to merge into the second portion. Like the stomach, it is invested by peritoneum on both surfaces. This membrane is derived from the gastric omenta previously described; the extreme right of the gastro-hepatic omentum being some- times called the ligamentum hepatico-dmdenale. The latter fold of serous membrane also forms the anterior boundary of the foramen of Wins- low, or opening by w hich the general sac of the serous membrane communicates with the bag of the omentum ; and it contains the hepatic duct and vessels. The above relations of this first portion of the duodenum to the peritoneum confer upon it a mobility which approaches that of the stomach ; while its close proximity to the gall-bladder explains that discoloration by bile which is generally seen in the dead intestine, — as well as the adhesion and ulceration of its parietes, which so frequently occur in the course of disease of the liver or gall-bladder. The second, the descending or vertical por- tion, which is rather less than three inches long, passes downwards, and slightly inwards, to the right side of the third lumbar vertebra. Above it is the right lobe of the liver. In front it is crossed by the right extremity of the transverse colon. Behind it is the inner border of the right kidney, together with a variable extent of its anterior surface, and its emulgent vein. On its right side is the ter- mination of the ascending colon. On its left it is intimately connected' with the head of the pancreas. Every one of these anatomical relations has more or less pathological im- portance. The partial covering of peritoneum received by this portion of the duodenum may be traced, from the front of the great omentum, to the anterior surface of the intestine ; and around its external or right side, to the wall of the abdomen. Here it is fixed to the right kidney, by an attachment that is sometimes termed the ligamentum duodeni renalc. The posterior and left surfaces of the intestine, which are devoid of this serous membrane, are connected with the neighbouring organs by a loose areolar tissue, that concedes to the tube a considerable degree of distention and movement. The third or inferior transverse portion is about five inches in length. In its course across the spine it lies upon the structures already named. Above it is the lower border of the pancreas. In front of it is the pos- terior or attached border of the transverse meso-colon, — the superior lamina of which covers it above, the inferior below, so as to leave an uncovered space along the line of their bifurcation. Anteriorly to this double process of peritoneum, is the large and moveable transverse colon which it serves to attach. And close to the commencement of the mesentery the end of the duodenum is crossed by the su[)erior mesenteric artery and nerves. Owing to this very partial covering of serous membrane, the inferior transverse portion of the duodenum is even less mobile and dilatable than either of the preceding. And, from the position of the pancreas above the intestine, distention of the latter cliiefly affects its inferior surface, which may thus be rendered so convex and bulging as to cover the aorta to within a very short dis- tance of its bifurcation. Hence the duodenum becomes most fixed in the second and third divisions of its course. Its fixation and curvature may together assist in delaying the passage of its contents, and in facilitating that admixture of the biliary and pancreatic secretions to which its attachment perhaps chiefly refers. Its use as a means of fixing the stomach has already been suffi- ciently alluded to. Its comparative immunity from hernia is explained by its site. The jejunum and ileum. — Below the duo- denum, the small intestine is loosely attached to the posterior wall of the belly by means of a double lamina of peritoneum which is called the mesentery (firros middle, ivTepov intestine.^ Behind, this fold is fixed to the cellular tissue that covers the aorta and vena cava, by a line of attachment which is not quite vertical, but descends from the end of the duodenum to the commencement of the caecum, passing very obliquely across the spine from the left to the right side of the lumbar vertebrae. In front, its two laminae split to enclose the bowel, around which they become continuous with each other. Its antero-posterior depth between these spinal and intestinal borders is about three or four inches ; but tapers away suddenly at its com- mencement and termination. We may, per- ha[)s, gain a better idea of the peculiar shape of this process of peritoneum by imagining it as a very obtuse triangle of some flexible material. Such a triangle we may suppose fixed to the spine by a truncated apex of three inches in length. While its broad base, which is about twenty feet long, is attached to the intestine, where it is plaited so as to occupy the least possible space. It is the extreme freedom of movement which such a mode of attachment concedes to the small intestine, that gives rise to the convoluted appearance so characteristic of this part of the tube. The exact figure of these convolutions is probably never quite alike at any two different times in the same indi- vidual,— being the conjoined result of the muscular movements of the canal, the nature and amount of its contents, the size of the neighbouring viscera, and the state of the abdominal parietes. The effect of dilatation resembles that seen in some other parts of the alimentary canal : — namely, distention of the tube always causes it to split up the loosely connected laminae of peritoneum, and z 3 3i2 STOMACH AND INTESTINE. extend hiickwards between them, so as to shorten the length ofits tether of mesentery. The terms jejunum and ik'um refer to a division of the small intestine which, though to some extent an arbitrary one, is not only too convenient to be altogether dispensed with, but is also connected with certain pecu- liarities in the structure of the mucous mem- brane, that will be hereafter alluded to. The jejunum includes the upper two-lifths, ancl the ileum the lower thrcc-fifths, of the small intestine.* Muscular coat. — The muscular coat of the small intestine consists of the fibre-cells pre- viously tiescribed, the bundles of which are arranged in two layers, — an outer or longitu- dinal, and an inner or circidar. The first con- stitutes a very delicate lamina, which is often scarcely visible at the mesenteric border of the tube, but is thickened at the opposite margin, where it is firmly uniteil to the perito- neum. The circularfibres form a much stronger and more perfect stratum ; and many of their bundles, like those of the same layer in the stomach, seem to take a slightly oblique di- rection ; so as to join with others above and below them. Both layers (and especially the transverse) are somewhat stronger at their commencement in the duodenum. But from the mitldle of the jejunum their thickness remains unaltered throughout the rest of the small intestine. Alovcments of the intestine. — The muscular actions of the intestine have long been re- duced to two: — -a normal pciistalsis, which urges the contents forwards towards the anus ; and an abnormal antiperistalsis, by which they arc propelled backwards towards the stomach. But each of these movements has rather been maintained as adoctrine, than vei'ified as a fact. From the mere tenuity of the muscular coat of the small intestine, we might infer that its movements are much less vigorous than those of the stomach and oeso[)hagus, in which this tunic has a thickness from two to six times as great. Indeed, an active and continuous peristalsis, like that which may be seen in these segments of the canal, would scarce tdlow the time necessary for the diges- tive act. Even a slow progressive contrac- tion of tw'o inches per minute would traverse the whole length of the intestine in from two to three hours : — a speeil which we have every reason to believe very unusual in the healthy subject. To obtain direct evidence respecting these movements, various methods have been re- sorted to. In the healthy living intestine, it is but very rarely that any definite muscular action can be seen or felt through the wall of the belly. In some of the Polyps, however, the * The former derives its name from the jejune or empty state in which it is usually found after death : and the latter either from its convoluted form (ecAeo), circumvolvo), its being the most fre- quent seat of the disease called ileus, or its relation to the iliac bone (os ilii). alimentary canal appears to exhibit a peri- staltic, but intermittent, movement. And in Man, the borborj/gmi which sometimes occur in conditions but little removed from those of health, constitute sufficient evidence of a valiil intestinal movement. While in cases in which abnormal obstruction of the intestine has been followed by an accumulation of fluid in the segment above the occluded part, the wall of the belly often becomes so extremely distended and thinned, as to allow us to re- cognise a progressive rolling contraction of the dilated bowel. Such observations at least prove that its muscular coat is capable of very vigorous contraction, while in this state of undue distention. When the intestines of a healthy living animal are exposed by vivisections, surgical operations, or accidental injuries, they are found at rest. Hence, could we implicitly trust these appearances, we should assign but a very slight mechanical value to the intestinal contractions. But such an estimate would obviously be at variance with that propulsion of their contents which we know them * to effect. And, apart from this implied contradic- tion, it is evident that such observations can never be regarded as affording us trustworthy evidence of what really obtains in the healthy uninjured animal. For not only is it possible that the slow and feeble contractions of the intestine are much interfered with by the pain and disturbance which such operations or accidents presuppose, but I would add, that there are considerable grounds for suspecting that irritation of the peritoneal tunic of the bowel can produce relaxation ofits subjacent muscular coat, f Until lately, it has been usual to augur the movements which occur during life, from an inspection of the intestines of healthy animals immediately after their death. On laying open the abdomen of a newly-killed animal, its intestines are seen lying perfectly still. But in a short time, those parts of them which are exposed to the air begin to experience vigorous contractile movements. In many instances, these contractions are irregular and undefinable, and are hence rather “vermicular” than “ peristaltic.” But in other cases, they take on appearances of a forward or backward course, or sometimes of each of these direc- tions alternately. Where transverse constric- tion is marked, it almost always takes a di- rection downwards, or towards the anus; and is [ireceded by a ddatation which stretches the intestine to the full length of its mesen- . tery. After a few minutes, the contraction of * It can scarcely be necessary to argue the ques-dr- tion which has sometimes been raised: — namely, T.' whether it is the muscular wall of the belly, or the muscular coat of the intestine, tliat propels the con- tents of this tube. For this is obviously an inquiry, which might be decided by a reference to its human and comparative anatomy, even in the absence of all direct observations as to the nature of its contrac- tions, and their necessary mechanical effects. f The effect of scratching the peritoneal coat (see opposite page) is perhaps partly due to an action of this kind. STOMACH AND INTESTINE. 343 the intestines generally gives them a nodu- lated or almost moniliform shape, and the movement gradually ceases. On uncovering portions of the canal hitherto concealed, all these appearances are repeated. The con- tracted state remains for some hours, and finally again disappears. Now the tranquillity of these portions of intestine previously to the atlmission of air, the irregular and diffuse nature of the con- tractions themselves, the final result on the intestine, and the effect of uncovering fresh portions — all these circumstances together offer the strongest probability, that the move- ments witnessed are due to the contact of the air. And hence, although it is interesting to notice that these contractions often assume the form of a peristalsis (that is, of a circular constriction which travels slowly in a direc- tion towards the rectum), still they do not warrant any conclusions as to the nature or force of those definite movements which are doubtless executed by the intestines during life. Nor are the movements which result from applying a local irritation to the bowel, under the same circumstances, much more uniform or conclusive. Unless excited before the commencement of the vermicular movements, or towards their close, they are obviously liable to be confused with these; — which, indeed, they closely resemble. Thus, when the surface of the bowel is irritated mechani- cally, a mere local contraction is sometimes produced. In other instances, and especially when the duodenum is the part attacked, the contraction extends downwards, or even upwards, from the irritated point. Sometimes this diffused contraction occurs almost imme- diately after the application of the stimulus ; sometimes onl3' after the lapse of a consi- derable interval of time. Sometimes, without any repetition of the stimulus, such waves are repeated; with short intermissions, and of gradually diminishing strength. Sometimes, instead of one continuous wave, a broken or interrupted one is produced ; — a condition which is chiefly seen in the small intestine. Similar contractions may also be excited by the mechanical or chemical irritation of the nerves which immediately supply the intes- tines. But irritation of the mucous membrane has little or no effect. Direct galvanic stimu- lation, by means of the rotaiy electro-magnetic apparatus, repeats many of these appearances. On api)lying the approximated electrodes to a given point, a short interval precedes the occur- rence of a local contraction ; and this con- traction endures after their removal. In some animals, this local contraction is ' jwly propa- gated onwards, for a variable distance, towards the rectum. This continuous movement may even be repeated without any fresh appli- cation of the stimulus. But that more diffuse irritation which may be produced by stroking the intestine with the wires gives rise to none but local contractions. While galvanizing the nerves reproduces the lively, but general, movements above alluded to. And finall}', whatever be the form of in itation, it ceases to have any effect, soon after the lapse of that period at which the vermicular movements usually cease. This departure of irritability may, however, be retarded by warmth, or by preventing the access of air. And the capacity for such movements may sometimes be re- stored by returning the divided and dead intestine to the belly of the living animal. Finally, though the repeated irritation of any one part soon exhausts its contractility, still, after a short interval of repose, it is at least partially restored. On mechanically irritating the exposed intestines of the living animal, very different results are obtained. Compressing them between the fingers produces a local con- traction, which lasts some few minutes, and then disappears. Scratching their peritoneal surface usually gives rise to elevations, which are just as local as the preceding depressions. These elevations, — which seem to be due to relaxation of the outer or longitudinal mus- cular layer, — are accompanied by contractions of the tleeper transverse fibres. And the latter can still be excited, after all possibility of pro- ducing the former has been destroyed by colli. Mechanical or chemical irritation of the mucous membrane, or pinching or section of the nerves, produces no movements what- ever ; — even where the degree of nervous sti- mulation is such as to cause convulsive move- ments of the hind feet of the animal. And distention of the bowel with water seems to be equally inefficacious; indeed, it appears to leave the ordinary irritability by local stimuli very little affected. The observations of Schwarzenberg and Ludwig *, upon dogs in whom intestinal fistulse had been carefully instituted, afford much more direct and trustworthy evidence respecting the normal intestinal movements. They introduced into the canal balls of wax, attached to slender lead wires ; and thus verified the following details. The contents of the canal are propelled by a slow continuous peristalsis, which has a definite direction towards the rectum. And although irritation always excites a local contraction, it only gives rise to peristalsis at definite times, during the intervals of which the intestine remains at rest. These times have a general connection with the digestive act: the period of minimum activity being before a meal ; while the maximum of movement is usually from four to six hours after it. But the act of peristalsis is essentially independent of the presence of food ; since it may be produced in a starving animal, or in an empty segment of tube. And not only does this intermittent character affect the general occurrence of the propulsive act, but even, to all appearance, its specific phenomena. For when applied at the proper period, a single continuous irri- tation produces a repeated and intermittent peristalsis. Flence it is obvious that, during * ZeitschriftfuerdieI!ationellenPathologie,Bd.vii. p. 315. z 4 3W STOMACH AND INTESTINE. the short intervals of this peristaltic act, the irritation is incapable of exciting contraction. We may perhaps sum u[) all these re- sults as follows. Direct irritation of this mass of organic muscle excites loca con- tractions ; which are of slower access, feebler power, and longer duration, than those of the striped fibre. Shortly after death, these con- tractions of the intestinal coat evince a general disposition to extend beyond the site of their origin. But during life, this tendency is so modified by some governing force, tliat, in obe- dience to the rec)uirements of the digestive organ, it is either exalted into a definite and effective peristalsis, or altogether suppressed. Tills definite peristalsis forms the ordinary mus- cular action of the bowel ; and is the chief agent in the proper propulsion of its contents. As regards its intensity, we can only conjec- ture that it is scarcely more than sufficient to propel the normal contents. As respects its character, it is essentially intermittent. As to its extent, it seems to traverse long segments of the tulie. But it remains very doubtful whether every — or indeetl any — contraction proceeds continuously throughout the whole length of the intestine. Finally, we have a right to suppose, that at least the more active forms of peristalsis have in them so much of rhythm, as to be not only repeated, but self- repeating, at definite intermissions of time. But the exact mechanism of this peristalsis remains in obscurity. Nay, more, the infor- mation at present at our disposal will not even enable us to take the first step in that process of induction by which alone it will [)robabIy be arrived at. In his admirable Essay on Muscular Move- ment, E. Weber* haswell illustrated the peculiar characters of the contractions which are ex- cited by the irritation of organic muscle. He has shown that in the Tench {Cypiinus tinea), in whom the muscular coat of the intestine is composed of striped or animal fibre, galvaniz- ing the chief nerves of the tube produces an immediate, powerful, ami coteinporaneous con- traction, in place of the slow, feeble, intermit- tent, and enduring action seen in the unstriped or organic intestinal muscle of the other Cy- prinoid species. He has also found that the Iris of various animals repeats the same con- trast of structure and irritability. Hence he argues, that the organic muscle is less directly influenced by the nerves; and that these are only connected with this contractile tissue in some such mediate way, as that by which irri- tation of the sensitive or afi’erent nerves gives rise to the reflex movements which are pro- ducible in voluntary or striped muscle. But do these facts warrant such a conclu- sion ? On the contrary, do they not render it more probable, that the above varieties of contraction are in some way inherent to the very structure in which these kindred animals ditt'er, rather than that they are brought about by supposed differences of the nervous centres or trunks : — differences (by the way) such as the existing state of our knowledge would rather * Wagner’s Handwoerterbuch der I’hysiolcgie. contradict than establish ? In the intestine of a single Cyprinoid species, the fibre-cell gives place to the striped fibre. Hence, failing all proof of other differences, is it not precisely to this remarkable contrast of struclure, that we must refer the parallel contrast which is observed in its contraction, when a stimulus is applied to its nerves ? This direct reference to the structure of the organic muscle seems to be most justifi- able in the case of the local contractions above alluded to ; many of the peculiarities of which are almost what might have been expected from the rudimentary structure, the little vascularity, and (especially) the mode of aggregation, of the fibre-cells. But as re- gards the less local contractions of the un- striped fibre, their tendency to peristalsis and intermission soon after death, appears to de- mand some wider and less continuous connec- tion of different points and times, than the tissue itself would directly afford. Such a means of association suggests itself in the ner- vous system. And, since the removal of the mesentery does not deprive the contractions of this peristaltic character, any supposition of this kind would appear to refer it to the nerves within the walls of the intestine. But it is difficidt to believe that these nerves have ganglia ; nor have any of these essential elements of a nervous centre ever been seen in this situation. While it has been pointed out by Wild, that the excision of a portion of the oesophagus prevents all propagation of its peristalsis beyond the interrupted point: — a fact which temis to show that the contraction of each segment is in some way conditionated by that of its immediate predecessor. The latter experiment, however, supposes such a serious interference with the tube, that any negative result can hardly be regarded as con- clusive. And hence, until future researches bring additional information respecting the ultimate distribution of the nerves of this un- striped muscular tunic, and the exact arrange- ment of its constituent fibre-cells, the relative share of the muscular and nervous tissues in these peculiar contractions can hardly be con- jectured. The stimuli by which we excite them in our experiments are in reality far too rude, diffuse, and uncertain in their a[)plication, to afford much ground for a decided preference of either muscle or nerve, as forming the chief modulator of that contractility which is, no doubt, essentially inherent to the sarcous sub- stance itself. From the appearances noticed in the healthy intestine soon after death, it may be doubted, indeed, whether even this last phrase is quite specific enough; — whether we ought not to regard* contraction itself (rather than an ab- stract “contractility”) as the inherent pro- perty of the living organic muscle. In the observations just mentioned, we have seen that the death of the animal was soon fol- lowed by an irregular, but distinct, contrac- * A contraction answering to what has been phi- losophically distinguished by Professor Bowman as “passive"’ in the case of the striped muscle. STOMACH AND INTESTINE. 313 tion of the unstriped muscular coat of its in- testine : — a contraction which was apparently excited by the air, but was certainly indepen- dent of the nervous centres. This remained for a time, and then disa[)peared, never to return. Hence it seemed, in short, “ a kind of precipitate 7-igor iiiorlk, hastened by expo- sure to the air.”* The truth of this analogy between the un- striped and the striped muscle is confirmed by observations made on corpses in which all ex- posure of the intestine has been avoided until an hour or two after death. A comparison of such examinations would show that the death of the intestine, like that of the ar- teries, is accompanied by the access of a definite ligor mortis, which is closely analogous to the sti&ning seen in the voluntary muscles. Both the access and disappearance of this contraction are, however, more rapid than in the striped fibres of the proper organs of locomotion. And its appearances are much less distinct. In the intestinal canal, it is chiefly recognized as a narrowing of the tube; which is attended by an increased thickness of its walls. But it is sometimes better evi- denced by intus-susception of the canal; or by irregular contractions of its calibre. But whatever the exact relation which the various contractions producible in the intes- tine bear to the specific structure that forms its muscular wall, it seems certain that the true propulsive peristalsis of the healthy living ani- mal is a complex and co-ordinate act, which is at least indirectly dependent upon the cerebro- spinal centre. And Weber’s experiments on the highly excitable intestine of the Tench point definitely to the medulla oblongata, as that segment of the nervous centre by which this connection is chiefly brought about. While, as might have been expected, numerous observations concur to represent the pneumo- gastric and splanchnic nerves as the channels by which this central organ influences the alimentary canal. But the exact degree in which the various vertebral and prever- tebral centres of the sympathetic can trans- mit, modify, or originate the nervous changes which pass to and from the bowel, is at present utterly unknown. There are how- ever various reasons for suspecting, that neither of the two main ganglia which inter- vene between any part of the intestinal sur- face and the cerebro-spinal centre, really limit the transmission of an afferent, or give origin to an efferent, change. Anti~perktalsis. — The ordinary theory of intestinal anti-peristalsis may be thus stated. At a certain stage of an intestinal obsti'uc- tion,the immoderate irritation which it implies reverses the natural peristalsis of the bowel ; so that, instead of proceeding towards the anus, it passes in the contrary direction. In this way it impels the contents of the tube towards the stomach ; whence they are vo- mited by the aid of an extension or reproduc- tion of the same action. About eight years ago, the author f was led * Author, op. cit. f Op. cit. to investigate this doctrine, until then uni- versally accepted. He was thus led to the conviction, that it ought to be uncondition- ally rejected ; that it was probably false ; and certainly had never been proved to be true. The following were his chief reasons for coming to such a conclusion : — 1. It is difficult even to conjecture any- thing in the degree or kind of irritation pre- sent in intestinal obstruction, which should limit the occurrence of anti-peristalsis to this state. 2. Since the physical state of occlu- sion is the necessary condition of fmcal vomiting, it is probable that the causa- tive process by which this occurrence is brought about must be physical also. 3. No anti-peristalsis has ever been observed ; — the movements which occur in the obstructed bowel after death being similar in their nature to those witnessed in the healthy intestine under similar circumstances. 4. The whole of the appearances seen after death in the obstructed bowel, show that its contents have been pro- pelled forwards towards the occlusion, and not backwards from it. 5. Distention of almost all the interval between the pylorus and the occluded part appears to be a condition of foecal vomiting ; — so much so, that the date of access of this symptom roughly indicates the locality of the obstruction. Hence, instead of an imaginary anti-peri- stalsis, the author ventured to propose a theory which seemed to deduce the process of fecal vomiting from the ascertained conditions of its occurrence. The complete obstruction of the intestinal tube at any point, gives rise to an accumu- lation of its contents above the scat of the structure. This gradual distention of the bowel is accompanied by an active propulsion, which may often be seen and felt through the wall of the belly, as a violent writhing peristalsis. After a variable period, vomiting either occurs for the first time, or if already present from other causes, it becomes fecal. But peristalsis in an obstructed tube dis- tended with fluid, not only implies a forward movement in the particles that occupy its peri- phery, but also necessitates more or less of a backward current in those which are situated in the axis or centre of the canal. And the uniform consistence of the distending fluid, or the return of solid feces, through many feet of tortuous bowel, into the upper [>art of the canal, constitute frequent phenomena, which are best explained by the mixture and circulation that these two currents must tend to establish. On the fecal fluid reaching the stomach, vo- miting is excited. And it is scarcely neces- sary to add, that this latter process, as usual, involves the more or less complete evacuation not only of the stomach, but also of the upper part of the distended small intestine. Mucous membrane. — Having thus briefly described the peritoneal and muscular coats of the small intestine, we may next proceed to consider its mucous membrane: — the struc- ture on wdiich its various functions essentially depend. STOMACH AND INTESTINE. 3-16 Tills tunic everywhere consists of the ordi- nary elements of a mucous membrane: — namely, a basement membrane, an epithelium, and a layer of areolar tissue that contains an admixture of the muscular fibre-cells. But, instead of forming a simple, flat expanse, it undergoes numerous modifications; which, un- der the names of valvulic connivcvles, intestinal tubes, villi, agminate follicles, solitary follicles, and racemose glands, will especially claim our notice. ValvxdcB conniventes. — Almost all the small intestine is complicated by the presence of transverse folds of mucous membrane ; which project from its inner surface into its cavity. These projections, which were known to many of the earlier anatomists, were named by Kerkring the valmdeje conniventes ; — apparently from his thinking that they ilelayed the intes- tinal contents, but still as it were, connived at their passage. They begin in the second portion of the duodenum, and only cease in the lower fifth or sixth of the small intes- tine. They are best shown by moderate dis- tention of the tube with alcohol ; which slowly hardens them, so that they retain their shape, even after a [lortion of the wall of the bowel has been rcmovetl to display its interior. — Fig. 255. Smnll Intestine distended and, hardened hi/ alcohol^ and laid open to shov) the vahnlae conniventes occnpyhiff its interior, (^From a preparation in the 3Iuseum of Kiny^s College.') Extreme distention greatly diminishes their size, but never effaces them altogether. And such a permanent character sufficiently distin- guishes these folds from those temporary creasings which are seen generally throughout the stomach and intestine, and which are sometimes spoken of as preceding them in the first part of the duodenum. At first they are very small and scattered, rise little above the general mucous surface, extend but a short distance across the tube, and break u|) at their extremities into stdl more minute creases, which often pass oblicpiely to join those next them, above and below. In the lower part of the duodenum, they gradually acquire a number and size, which are retainerl throughout the whole of the jejunum. But from the beginning of the ileum, they again diminish; first in frequency, and latterly in length and depth. And in the lower third of this segment, they generally disappear alto- gether. Each of these folds consists of a duplica- ture of mucous membrane, enclosing a process of the loose areolar tissue which everywhere separates the mucous from the muscular coat. t>pposite the attached border of the valvida, this layer is somewhat thicker; but does not ap[>ear to contain more than its ordinary small quantity of fibre-cells. The [)rocess which it gives off to each of the folds con- tains vessels, nerves, and lacteals. The relation of this tissue to thevalmda is well shown by the result of its inflation ; which produces a kind of artificial ein|)hysema, that completely oblite- rates the whole projection. When the cavity of the intestine is forcibly distended, the valvida’ are placed vertically to the general surface. But in the ordinary state of the bowel, they are easily moved by any ex- ternal force ; so that their free margin is generally directed obliquely upwards or down- wards. Their direction is nearly transverse to the axi.s of the tube. Their variable extent around the wall of the bowel forms one-half, two-thirds, or even three-fourths of a circle. Their greatest projection occupies the middle of their length, where they are often from one-fourth to half an inch deep. But towards either extremity, they gradually sink into the general mucous surface. In doing this, the valves usually swerve a little from their hither- to transverse and parallel course ; so that each joins by one or both ends with the fold imme- diately before or behind it. And sometimes a bifurcation of the tapering fold unites its extremity to two of its neighbours. The office of these permanent folds has been a matter of considerable speculation. It is evident that they increase the extent of the mucous surface to at least twice or thrice what it would be in a simple hollow cylinder of equal size. It is equally obvious, that their transverse position is peculiarly calculated to render this enlarged surface an effective one. For they are at right angles to the direction of peristalsis, and therefore to the genera! cour.se of the intestinal contents. Such an arrangement of the mucous membrane, taken in connection with the great mobility of these folds, must not only insure a thorough ad- mixture of the various constituents of the ch^me, but, by delaying its direct passage onwards, bring every portion of it into con- tact with the greatest possible extent of the active intestinal surface. Intestinal tubes. — The structure of the remaining constituents of the intestinal mu- cous membrane can only be seen distinctly by the aid of the microscope. Amongst these minute organs, the intestinal tubes — • or, as they are commonly calletl, the folli- cles of Lieberkuehn — are the first to de- mand our notice. For, with slight modifica- tions, they occupy the w'hole of the small and STOMACH AND INTESTINE. 347 large intestine. AiT allusion has already been made to the fact that, in many animals, they appear to usurp a portion of the gastric cavity. While the importance which this wide distri- bution would imply, is confirmed by their im- mense number ; which is such that we may estimate their aggregate surface as from ten to fifteen times that of the cylinder of intes- tine into which they open. Each tube may be described as a hollow cylinder, having a length which is about five times its width, and ending below in a rounded Fig. 256. Intestinal tubes from the Jejunum, asseen in a vertica section. {3Iaguified 80 diameters.) a. Limitary or basement membrane ; ft, nuclei of the columnar cells which line its interior; c, calibre or cavity of the tube ; d, mouths of the tubes opening into the general cavity of the intestine; e, blind extremities of the tubes, corresponding to the sub- mucous areolar tissue. blind extremity. Its average diameter is about -si oth of an inch, except at its orifice, where it is somewhat wider. The lower part of the tube is often slightly enlarged : and rarely it appears to bifurcate. But while it is doubtful whether these appearances can be depended upon*, it is certain that they are not sufficiently marked or frequent to alter the above general description. -|- This cylindrical tube is composed of base- ment membrane and epithelium. The former constituent needs no special description. The latter is a single layer of short columnar cells. It clothes the whole interior suiface of the tubes ; and becomes continuous, at their upper extremities, with the epithelium covering the villi, the constituent cells of which generally appear to be somewhat longer in shape. The cylindrical cavity bounded by these cells has * See foot-note to p. 321. f A more valid exception to the above statement may be found in the upper part of the duodenum of some of the domestic Mammalia ; in whom many of these tubes divide, a little below^ the surface, into three or four smaller ones. This condition may be regarded as a transition from the structure of either the pyloric tubes, or the clustered glands of Brunn, to that of the ordinary intestinal tube. From the appearances offered by the cylindrical epithelium that lines their interior, the first of these conjec- tures may be regarded as the more probable of the two. a diameter which amounts to about one-fourth the width of the entire tube. The arrangement of these tubes so precisely recalls that of the gastric glands into which their structure appears sometimes to merge, as scarcely to require any separate descrip- tion. Like these, they are placed vertically sitle by side, in a sparing quantity of dense fibrous matrix ; and are imbedded by their lower extremities in a layer of a similar ap- pearance. The latter contain much unstriped muscle, the characters of which can be seen Fig. 257. Vertical and longitudinal section o f the small intestine in the lower part of the jejunum, showing the general arrangement of its coats. (^Magnified 50 diameters.) a, villi ; ft, intestinal tubes ; c, submucous areolar tissue; d, circular fibres of the muscular coat ; e, longitudinal fibres, external to these, covered by peritoneum. ^ even more distinctly than in the analogous gastric structure. The aggregate mass of these vertical tubes forms the great bulk of the mucous membrane. So that a vertical section of this tunic exposes a dense pallisade of tubes, the depth of which corresponds to the thickness of the membrane: while a trans- verse one shows that the interstices of the cylinders are only occupied by a scanty matrix enclosing numerous vessels. The chief interruption to their presence is caused by the racemose glands, villi, and fol- licles, which will shortly be described. The ducts of the first of these three structures merely occupy a certain portion of space which would otherwise be taken up by follicles. But the two latter encroach upon the surface of the mucous membrane much more con- siderably. And since it is only between the villi that we find the intestinal tubes, so the number of such tubes which occupy the inter- vals of these processes must necessarily cor- respond to the thickness with which the latter are strewed over the surface. Over the more projecting parts of the follicles, the tubes are also absent ; in a circular space which is sur- rounded by a ring of apertures. The latter belong to the inflected upper extremities of 3i8 STOMACH AND INTESTINE. those tubes which immediately encircle each follicle. When fresh, these tubes always exhibit the structure just described ; tlieir only contents being a clear, structureless, homogeneous fluid. But from their minute size, it is obvious that this fluid can never he obtained from their inte- rior in sufficient quantity for any trustworthy analysis. While unless the secerning process were extremely ra|)id, even the secretion poured forth into the tube would often be mixed with those coarsely filtered contents ot the intestine which can enter its upper orifice from the general cavity of the alimentary canal. And as regards all fluids found in the gene- ral cavity of the intestine, we ought never to forget that to procure them in a state of abso- lute purity is impossible. Under normal cir- cumstances, the fluid present in any part of the bowel can only be regarded as a complex mix- ture of several ingredients, all of which are probably themselves undergoing a continual metamorphosis. Could we deduct from the contents of the intestine all chyme, bile, and pancreatic secretion, the residue would be strictly an intestinal juice. And by far the larger quantity of such a Juice would be com- posed of the secretion of the intestinal tubes. Now we shall hereafter find that analogy sup- plies us with some plausible conjectures re- specting the fluid secreted by the duodenal glamis. While the closed follicles which abut on the cavity of the bowel can scarcely furnish sufficient fluid seriously to affect the composition of any mixture which it may contain. Hence whatever the share taken by the villi, the secretory office of these tubes might ap|)arently be to some extent determined from an examination into the chemical and physiological properties of even such an im- pure or mixed intestinal juice. The reader will, however, hardly be sur- prised when he is informed, that these condi- tions have never yet been fulfilled; and hence, that a satisfactory account of this interesting fluid remains at present impossible. But he must not therefore think the above allusions superfluous. For it is only by a reference to these conditions of experiment, that we can judge how far we ought to accept the state- ments made by various recent observers re- specting this fluid. Thus Frerichs* * * § obtained intestinal juice from fasting cats and dogs, in whom a few inches of intestine had been emptied, and tied at both ends, about five hours before they were killed. Lehmann j- procured it from a fistula of the small intestine, which had fol- lowed an operation for hernia in the human subject ; and in which another fistula, higher up, gave passage to the ordinary mixed con- tents of this part of the alimentary canal. Zander j; instituted fistulae in animals. And, finally. Bidder § and Schmidt, who adopted Frerichs’ method without obtaining one drop * Op. cit. p. 850. t Op. cit. vol. ii. p. 112. j Koelliker, Op. cit. § Lehmann, Loc. cit. am] Bd. iii. s. 335. of intestinal juice, carefully compared the mix- ture withdrawn from simple fistulae, with a very small quantity of a purer fluid which was yielded by dogs in whom the pancreatic and biliary ducts had been tied, and the gall bladder made to discharge its contents externally. According to all these observers, the intestinal juice is a transparent, viscid, and strongly alkaline fluid. It contains nuclei, and round or columnar nucleated cells; — an abortive cell-growth, the admixture of which does not substantially affect the struc- tureless character of the secretion. Of its composition and reactions we can only saj', that it apjjears to contain mucus and the ordinary salts ; which together form a solid residuum, that amounts to about 2 per cent, of the whole quantity of fluid.* As regards the physiological properties of the intestinal juice, it has the power of con- verting starch into grape sugar. But however obvious the usefulness of this capacity, it is possessed in an equal degree by so many other animal substances, that it can hardly be re- garded as the specific purpose or function of this secretion.f But the recent observations of Zander, together with those of Bidder and Schmidt, claim for this secretion a much more impor- tant office : — an office which would entitle the whole of the small intestine to that ap- pellation of a “ ventriculus succenturiatus, ” which was formerly bestowed on the duode- num. These observers agree in the state- ment, that the intestinal juice dissolves protein- compounds, both in and out of the body. Anil from the careful quantitative researches of Bidder and Schmidt, it would follow, not only that its solvent powers upon these sub- stances are from three to four times greater than those of the gastric juice itself, but that in the Dog, about half the daily albumen of a flesh diet is habitually left untouched by the stomach, to undergo solution in the intestine by the secretion. Against such a conclusion I would suggest the following arguments, which together in- duce me to think that this doctrine ought not at present to be accepted. That a large organ like the stomach, with a definite and com- plicated structure, should so incompletely discharge its single chemical function, is a paradox which alone involves a great improba- bility. This suspicion becomes still stronger when we consider that, under normal circum- stances, gastric juice is always conveyed from the stomach into the intestine during the pro- cess of gastric digestion ; while it is evident that none of the experiments by these observei s quite exclude the possibility of such a transit. Nay more, if we suppose — what is surely not * Bidder and Schmidt observed a much larger quantity in the mixed fluid ; but point out that the fixed contents would be raised by the addition of the more concentrated secretions of the liver and pancreas. Hence I prefer quoting the estimate deduced by Lehmann from what was probably a purer fluid. ■f Compare the remarks on the pancreatic fluid, in a subsequent part of this article. STOMACH AND INTESTINE. impossible — that the juice carried onwards into the intestine is there concentrated hy the partial absorption of its watery part, some of the strange quantitative results obtained by Bidder and Schmidt cease to be altogether in- explicable. It may indeed be urged, that the alkaline character observed in the intestinal juice sufficiently proves that its digestive pro- perties are not derived from the stomach. But although the addition of a caustic alkali destroys the efficiency of gastric juice, still such a process seems very different from that absorption of acid, or that gradual admixture of a dilute alkaline solution, by which a similar reaction would probably be communicated in the living intestine. And, finally, is it like the ordinary economy of Nature, that an elaborate secretion should pass the pylorus, to be at once annihilated, and then replaced by a second and equally complex antagonist juice ? On such a supposition, indeed, there are many animals in whom almost all the gastric juice would be wasted. For example, there is great reason to suppose that the sojourn of food in the Horse’s stomach is so brief, that anj thing like the stomach digestion of Carnivora is imj)ossible. But are we therefore entitled to assert that this organ is utterly useless ? Such considerations appear to render it more probable, that the gastric juice may retain its digestive efficacy after passing through the pylorus ; and that the presence of this secretion in the small intestine suffi- ciently explains the solvent powers of the juice which is found in this situation. But we are not left to such arguments alone to disprove the solvent powers ascribed to the intestinal juice by the above observers. They receive a still more direct contradiction from the experiments made by Frerichs* and by Lehmann.j' These authorities concur to state, that neither in nor out of the body can it dissolve the protein compounds. And Leh- mann’s case may be regarded as affording much more than an ordinary negative re- sult ; since in it, all communication between the stomach and the fistulous aperture made use of, seems to have been excluded. Finally, we may recall to the reader that close parallel which was observed in the action of the gastric juice and the infusion of sto- mach ; — how, allowing for dilution and im- purity, we found the latter behaving just like the former. Now, in striking contrast to this significant fact, numerous observers J agree in representing the infusion of intestine as utterly incapable of that solvent action attributed by Bidder and Zander to its secretion. Indeed, Koelliker and Goll have found the cajia- city of digesting protein-compounds so inti- mately connected with the structure of the proper gastric tubes, as to be almost lost in the pyloric extremity of the Dog’s stomach ; where these begin to assume the characters * Loc. cit. {IjOc. cit. Koflliker, Valentin, Todd and Bowman, and others. 319 of intestinal tubes by losing their oval gastric cells. Hence all tliese 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 converse 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 cb.aracter 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 render 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 w hat is often only a single ring of capillary (b Jig. 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. STOMACH AND INTESTINE. laries of the neighbouring villi. And the venous radiclesof these latter processes usually unite with the branches formed by their coii- Fig. 258. Capillaries occupying the surface of the mucous mcm- Orane of the small intestine; as seen on examining an injected specimen hy reflected light, with a mag- nifying power of about 50 diameters, a, h, capillaries around the orifices of the intes- tinal tubes. At a their meshes arc more numerous and complex than at h, wliere 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 chylij'erous pa'pillee. 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 |)rocesses 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 (j^oth 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. Villus from the upper part of the jejunum, as seen in the Jasting state. Magnified 140 diameters, a, epithelium of the villus; h, parenchyma or sub- stance of tlie same. equal their own bulk. Here they also acquire their maximum length, which ranges from about to Jjjth, or even J^th or J^th of an inch. Their form, however, is still that of a flattened cone (comparey?g. 259. andyfg. 257. p..3'17.) ; — the breadth of the base of which is about ^th, and the depth about iJu^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 ^Joth of an inch in dia- meter. The villi cover the whole surface of the mucous membrane of the small intestine, in- cluding its valvulre 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, {a. Jig. 27'2, p. 358.) blunt, irregular, or even confluent, where they occupy their interstices. We have seen that each of the valvul® conniventes is a doubled fohl of membrane, separated by a layer of areolar tissue. While the minute intestinal tube may alniost 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, unstriped muscle, and numerous blood-vessels. And in ad- dition to these constituents, which may be found under various modifications throughout the whole 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. Jig- 259. and tz,y%s.264',265, 266.) consists of a single layer of c3lindrical 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. ^5- 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, (aa, Jig. 2QQ.) ofabout Ttroo*^h 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 oft' numerous capillaries, into which their own trunks entirely merge at about the middle of the height of the villus. The ultimate capillaries themselves (c c, 260. V a V a Vessels of two villi, injected. Magnified 100 diameters, a a, arteries entering tire 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; i, limitary or basement membrane of the villus, denuded of its epithelium Jig. 260.) are, on an average, about -^rd of the usually such, that the length of its meshes is aoove diameter. They constitute a net-work, five or six times their width. The capillaries which lies directly under the basement mem- are distinguished by their being apt to ex- brane ; and covers the whole villus so thickly, hibit a wavy and tortuous course (d. Jig. as to give it a vivid red colour in injected 260.) which often "causes their real length specimens. The shape and complexity of this 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 villus: — to the contrac- tion of the muscular layer of which it would appear to he chiefly, though not wholly, due. The veins (vv,fg.26Q.') 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 tlie bottoms of the tubes. It rarely presents any definite struc- ture. Sometimes, liowever,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 papilla? of the latter organ, the basis of wdiich 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, figs. 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 tbe whole of the structures wltich lie beneath the basement membrane. As regards the lactenls of the villi, few anatomical details have been more disputed than those which relate to the commence- ment of the chyiiferous 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 trustvvorthy 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 bj' 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 a[)ply 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 llabbit and Calf are es|)ecially suitable for examination. If pro[)er care be taken to examine the chyiiferous villi of these ani- mals instantly after ileath, with the aid of suitable fluids, we may easily convince our- selves of the [tresence of a single large lac- teal tube, with distinct walls, like that rejtre- sented in the annexed figure {Jig. 261.). Such Fig. 261. b d d b Two villi, dem/ded of epithelium, with the laetenl vessel in their interior. From the Calf. Magnified 350 diameters. {After KoelUker.') a, limitary membrane of the villus; h, 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,fig- 261.) which nearly doubles their width. In man, according to Frerichs *, thej' are scarcely more than one-half or two-thirds of this size. But it remains to be considered whether this * Op. cit. p. 761. STOMACH AND INTESTINE. 353 statement excludes the possibility of a net- work, such as has been afhimed to exist by Krause and others. Koeliiker, 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, — maj 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, Koeliiker 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. V^'e may add, that, in the various observations which have been made on executed criminals, the possibility of error has probably been in- cre.ased 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 blintl extremity. The vmsndar constituent of the villus was first discovered by Bruecke, ami has since been verified by Koeliiker in many Birds and Mammals. Its shape is that of a thin hollow cone, which closely imitate.s 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. * Op. cit. p. 100. et seq. t Op. cit. p. G84. Stij-ip, 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. Villus denuded of epithelium, treated with acetic acid. From a young kitten. Jflugnifed 350 diameters. {Afer Koeliiker.') a, outline of tbe villus ; h, nuclei beneath this ; c, nuclei of the unstriped muscle ; d, roundish nuclei in the centre of the villus. iinstripcd 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 ordinaiy 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 vi!lus, — to which it forms a kind of muscular and contractile envelope — has given rise to the suspicion, that it effects tbe 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 Koeliiker 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 irritation?. However A A 354. STOMACH AND INTESTINE. this to occur, it is evident that such a remittent contraction woukl not destroy the claims of tlie absorptive act itself to be eonsidered the chief force which propels the chyle. For in any case, the muscular apparatus would but limit and remove that distention of the lacteal which absor[)tion had previously ef- fected. It would thus, as it were, merely re- gulate and tr.ansfer 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 verily the action of this delicate muscular ap[)aratus ilur- ing life. Gruby and Delafond first instituted such observations on a variety of domestic animals ; and they have since been rejieated by Bruecke and Koeliiker. All of these authorities agree in remarking an alternate shortening and elongation of the villus : — 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 unstri[)cd 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 Villi contracted and shortened so as to offer circnlar nr transverse wrinkles. From the smalt intestine of the doq shortly after death. JUagnifed 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. » Por, — to say nothing of the pain, the irritation. v/rinkles or folds. A more minute examination shows that these folds consist of epithelium, which has sejiarated 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 villus 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 villus; b, granular matrix or substance of the same. those columnar cells which occupy the free extremity of the villus, fretiuently 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 villus witlulraws from its cellular investment with such uniformity, as to leave the extremity of the latter empty, smooth, and uninjured (_/?g. 264, ].), like the fingerof a glove. Frequently, how- ever, some of the epithelial cells are detached. It is obvious that all these appearances are rcferrible to a contraction of the un- striped fibres within the villus, 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 Delafond remark, that their surface becomes wrinkled ai'd 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 w'ould interpret them as part of a normal process. STOMACH AND INTESTINE. 335 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 [leriod, 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. ViUus of the dog about two hours after feeding ; show- ing the entry of fatty into scattered epithelia on its surface. 3Iagnified abotit 400 diameters. a, a, outline of the villus formed by epithelia with their ordinary contents ; b, b, epithelia rendered bright and retractile 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 {l>,Jig. 265.) and darker intervals.* Gradually, however, all the cells become similarly affected ; so that the entire villus 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. a Isolated epithelial cells from a villus, as seen during the absoiption of fat hito the lacteals. (^Altered from Koelliker.') Alagnified 350 diameters. a, columnar epithelial cell, occupied by fatty molecules; 5, similar cell, containing several small oil-drops; e, similar cell, enclosing a single oil- drop ; d, similar cell completely filled by a larger oil-drop. The upper or free end of the cell (at rf) js concave. but the result of the change is to give the columnar cell a darkly granular appearance (ff. 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-wall of the villus exceeds that of the * These appearances, alluded to by Frerichs (Op. cit. p. 854.) and detailed by Koelliker (Op. cit. p. 1 67.), were noticed by me eight years ago in the human subject. f Thelarger drops sometimes seen in this situation are, I believe, the result of accidental violence to the specimen. J Lemons sur les Phenomenes, &c., pp. 104, 5. § Op. cit. vol. i. p. 379. A A 2 35G 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 imlependent 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- dosmoineter. t)n 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 oil}' ; and not saponified, like such diffused fluids. And while the jiositiou 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 : that 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 f ; — changes, neither of which would probably have much direct effect on the ph ysical action of an indepenilent 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 <|uantity of fatty matter which can be absorbed. Hence when the amount of fat [iresent in any jtarticular region at all exceeds what its villi can take iqi, it is pa.ssed on to other portions of intestine ; failing absorption by which, it is ultimately discharged unchanged in the fieccs. IntcsHnal FvUiclcs.X — We pass on to the description of a class of structures which are essentially closed sacs; and vrhich, represented in the stomach by the lenticular glands, pervade all the remainder of the intestinal canal under the two forms of solitary and aymhiate 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 * Freriebs, Loc. cit. f Fenwick in “ Lancet ” for 1845, p. 64; J The etymology of the word '‘■follicle ” quite permits its application to these closed sac.s : to which indeed it seems desirable that w'e 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 gta?idulee Peyeriana; ; ar/inma Peyeri ; glandutce aggreyatce ; gtandulcB agmi- ■iiatai ; vesicnlarum agmbia ; plexus iiifestmalcs ; plaque, 14'0 and sundry animal matters . . . J 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 feces 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 feces into alimen- tary and secretory, w-e 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 Lehmann f, 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. Porterj; states that healthy feces, 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 feces of the Dog and Horse, which they found to contain 20 and 25 per cent, of ash respec- tively.T^ 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 tbe 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 Aimalen der Chemie mid Pharmacie, bd. Ixxi. p. 109. § Day’s Simon’s Chemistry, vol. ii. p. 375. j| Societe d’llistoire Xaturelle de Genbve, 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 37G STOMACH AND INTESTINE. absorption of lime than niagnes’a 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 ^tli or ^’oth 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 dilierent segments is probably a very uncertain as well as variable one. In diarrhcea, 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. Intestiml 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, liowever, 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 Chevillotf, 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 : — Whence obtained. Composition by Volume. V Oxygen. Nitrogen. Carbonic Acid. H5drogen. Carburetted Hydrogen. Sulphu- retted Hydrogen. Stomach - . - . Small intestine: average of three 1 analyses - - ' -j Coecuni - - - . Large intestine 1 2' ' Rectum - - - . Flatus expelled 7>er aniim (mean of ) two analyses by Blarchand) - j' 11-00 71-45 31-84 67-50 51-03 18-04 45-96 21-5 14-00 29-80 12-50 43-60 70-00 42-86 40-5 3-55 38-36 7-50 11-06 18-75 12-50 5-47 11-06 11-18 18-75 traces. traces. traces. -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 wdiich 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 Physiologie, 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. 377 STOMACH AND INTESTINE. circulates in the capillaries of the organ. And this difflision 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. While 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 w'ell 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 w'ould probably obey the same laws, and exhibit somewhat of the same eourse, 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 une.xampled 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- * Tlie legumen of which contains much of this element. 378 STOMACH AND INTESTINE. phuretted liydrogen — 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 tlieir secretion from it, to the extent men- tioned in tliese observations. To this we may add, that no parallel to such a process of gaseous excretion can he 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 arc 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 distinguishetl, 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 pro()ortion to the carbonic acid present, is increased from ^ Jijth in the former, to ^d, or even fths, 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 fooil 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 * Reclierches physiologiques sur les gaz intes- tinaux. 1824. t Oj/. cit., p. 866. these instances have absolutely excluded the presence of all alimentary substances; and that a very small quantit}' of liquid or solid matter would probably be quite sufficient to yiekl 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 alimejitary 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 defaecation 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 authors seem to be examples of a similar decompo- sition occurring in the blood and secretions con- tained in the cavity of the uterus. 379 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 coecum, and the first two-thirds of the colon. The Fig. 277. 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 ; f, 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 ce, ctecum ; a c, 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 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 ccBCum. 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 (i, fig. 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 coecum, and the lower {cjfig. 277.) towards the ileum. Thei/co- co/ic artery {b,fig. 277.), 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,fig. 277.), which passes tipwards 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 thelvessels 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,fig. 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 STOMACH AND INTESTINE. 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 successiv^e 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 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.* Distribution of the inferior mesenteric artery to the large intestine, a, abdominal aorta ; 6, inferior mesenteric arter}’ ; c, left colic artery ; cl, artery to the sigmoid flexure ; e, superior luEinorrlioidal artery ; /, middle colic artery ; g, large communicating branch between the left and "middle colic artery, s /, 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 occuj)ies the double fold of peritoneum (mcso-rectum) that attaches the rectum to the pelvis. This terminal portion of the vessel, which is called the sujcci-ior hee- morrhoidal artery {e,fi.g. 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 hcenwrrhoidat artery, which is itself given off to the rectum by the internal iliac artery, or sojne 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 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. I'eins 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 (a, fig. 279.), which passes upwards to the liver at some distance from the aorta and primary in- testinal branches.* • * See Art. Venous System. STOMACH AND INTESTINE. 381 third portion of the duodenum, it swerves towards the right side, from what was hitherto The veins of the intestines commence by a dense netw'ork, that receives the minute i i o. venous radicles into which the capillaries of an almost vertical course upwards ; and after the mucous and muscular coats return their blood. This plexus has the same submucous situation, and flattened shape, as the cor- responding arterial network already men- tioned; but, like the venous system in general, is composed of more numerous and larger branches. It gives off’ a number of veins ; wdiich 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 cceliac axis and the two mesenteric vessels. Many of Fw. 279. 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 ; f, pancreatico-duodenal veins ; g, branch of the portal trunk to the left lobe of the liver; h, similar branch to the right lobe. (The remaining letters indicate as in the pre- ceding figures.) them unite to form two chief trunks, the superior and the inferior mesenteric veins. While others open directly into the splenic vein ; or into the vena portce, which is formed by the junction of it and these mesenteric veins. The superior mesenteric vein (b. Jig. 279.), which receives the venous blood from that portion of intestine supplied by the artery of the same name, travels for some distance in company with the latter vessel ; lying on its right side, and somewhat superficially to it, and surrounded by very numerous lacteals and nerves. But near the lower border of the crossing in front of the duodenum at nearly a right angle, ends by joining the splenic vein behind the pancreas. This junction gives rise to the portal trunk (a,/g. 279.). The inferior mesenteric vein (c. Jig. 279.), — the origin of which also corresponds to the 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 {cl. 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 junction 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 S3 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 az\gos and portal veins. W^hile the lowest branches of the inferior mesenteric vein establish a similar and much more extensive anastomosis of the two systems, b\ their junc- tion w'ith a dense venous network — the hce- morrhoidal j)le.vus — which encircles the lower part of the rectum, and gives origin to the middle and inferior hoemorrhoidal branches of the internal and external iliac veins. The foregoing peculiarities in the vascular arrangements of the human alimentary canal are at present only susceptible of a very im- perfect explanation. As regards the arteries, their great number and size, and their large anastomosing chan- nels, would probably be attended by several ad- vantages. The variety of these channels w’ould concede to the circulation, not onl}' a large supply of blood, but one such as no ordinary local accident could at all interfere with.* The muscular fibre contained in their walls would allow these numerous tubes to exercise an unusual control over the amount of blood * Compare the remarks on the vessels of the stomach at p. 3Z7. 382 STOMACH AND INTESTINE. they from time to time convey. While on very sini[)Ie liyilranlic principles, these re- peated cross branches would so diminish tlie various resistances (of impact and adhesion) offered to the blood within the vessels, as to permit, either a greater rapidity of the cur- rent, and hence a more rapid renewal of the mass of blood contained in the capillaries ; or a more forcible pressure upon the latter fluid ; or even both of these effects simultaneously. It is [>erhaps a corroboration of the above conjectures, to trace their close relation to those which might be gathered from an inde- pendent consideration of the circumstances of the portal system. The trunk vein of this set of vessels leads to a second set of capillaries in the liver ; through which there is nothing to propel the portal blood, save the force of the heart, aided by a small amount of suc- tion, which the thorax exerts as it ex- pands during inspiration. And hence, how- ever large a quantity of the original cardiac pressure may be again amassed by the con- vergence of the various intestinal veins, still there can be no doubt that at least so much ol it will have been lost, as to require all the aid vvhich the above disposition of the arteries can afford it. But in spite of all such assistance, it seems probable, that the current of the portal blood is both far slower, and much more feeble, than that which occupies any of the arteries. Still it is no doubt quite sufficient for the exigencies of the circulation in the liver ; and especially for that secretion of bile, to which the various details of the organization of this gland chiefly refer. The Fool). — The function of digestion has for its chief object the replacement of that loss of substance which the body is con- stantl}' undergoing. Even the hardest materials of the globe we inhabit ex|)crience a gradual disintegration ; as the result of the various physical processes to which they are ex|)osed. Such processes may be instanced in the attrition and solution of solids, the eva|)oration of liquids, and the diffusion of gases. And hence, when we turn from these inorganic substances to the animal fabric ; and consider its slight cohesion, the friction which its locomotion implies, its large watery constituent, and the feeble chemical affinities which enchain its elemen- tary atoms — we shall scarcely be surprised to find, that the rapidity of its waste far ex- ceeds that of the inanimate solids around us. But the rate of waste, and the consequent need of replacement, both depend, far less on simple |)hysical causes of this kind, than on certain actions which are specific to the or- ganized body. These actions, which, in the aggregate, make up what we term Life, do not so much imply, as actually consist in, a per- petual process of flux and metamorphosis. This multiform change engages the whole of the corporeal tissues ; and conducts their various ingredients, through a number of suc- cessive phases of composition, to an effete and useless state, in which they are finally ejected from the organism. And hence, whatever the share taken by the physical actions of diffusion, solution, fric- tion, and evaporation, in the removal of the substance of the body, they are not in any sense the true causes of its process of waste ; or the real sources of its egesta or losses. They are but, as it were, the janitors of the animal fortress ; the nature and amount of the matters which pass out by them being controlled and regulated by the higher life that rules within. The ingesta, which replace these egesta, and thus form the opposite extreme of nu- tritional life, are equally influenced by the general requirements of the animal. Ex- cliuling, for the present, all consideration of that preponderance of absorption which de- termines the growth of a young animal, or the converse excess of excretion which results in the decrease and decay of an old one ; and limiting our attention to the mere maintenance of the adult body ; — we shall find that it is the composition of its structures, and the rate of their wear and tear, that chiefly determine the kind of food it makes use of, and the quantity it consumes within a given space of time. While as regards the exact degree of this dependence, we shall further find that, here as elsewhere, the operations of organized nature are only limited by wide general prin- ciples ; within which are apparently conceded great variety and fluctuation. The laws of nu- trition are, so to speak, universal in their range, but elastic in their application. In respect to the nature of the food, we may first notice, that by far the larger part of it is always derived from the organic, and never from the inorganic, world. In other words, the chemistry of the organism has little power of construction or synthesis. So that, although a proximate analysis of the tissues of the animal body presents us with compounds, which may be shown to consist chiefly of a few elementary substances united to each other in varying proportions, still the carbon, oxygen, hyilrogen, and nitrogen, which surround or penetrate the living animal, are never directly built up into these tissues. On the contrary, the various substances which form the proximate principles of the several structures of the organism are themselves produced by the metamorphosis of kindred compounds introduced iu the food ; — com- pounds which have been in their turn derived from the vegetable kingdom ; either directly, in the shape of plants, or indirectly, from sub- stances constructed out of vegetable tissues by the organism of another animal. And the inorganic substances introduced into the body seem to be almost restricted to the subordinate (though equally indispensable) office, of com- bining with these products of vegetable life, and modifying their actions in obedience to the necessities of the existing individual. The above statement as to the organic nature of the food suggests some interesting considerations. In the first place, it seems to shew that the living animal of to-day pre-supposes STOMACH AND INTESTINE. 383 another organization of yesterday ; — that its individual descent from two creatures of the same species is accompanied by a less evident, but quite as real, transmission of substance from several previous beings. In short, that the greater part of its entire mass might be regarded as the sum of various legacies, which have been bequeathed to the existing organism by the various plants and animals that lived before it. In the next place, it indicates a fixed and definite relation between the plant and the animal. The former is thus the chief agent in the constructive chemistry of the latter ; — a necessary link in that chain of processes which builds up organic principles, out of the elements of inorganic nature, or out of those simple products into which the particles of the animal body are finally converted by its waste during life, or its putrefaction after death. The carbonic acid given off by the living or dead animal may especially exemplify the latter remark ; converted as it is, by the vegetable, from a poisonous gas into a class of substances which are in the highest sense alimentary, and essential to the life of the animal. And lastl}^ since animal and vegettible life are thus complementary to each other, alike in their broader features and their minuter details, we may conjecture that, in the present disposition of our planet, they form what is in fact a tolerably constant magni- tude : — a sum of organized life, the amount of which is subject to but very slight varia- tion from one time to another. Nay more, we may almost suspect that the total of animal existence — the composition of which ranges thus regularly through vegetable or- ganization as an essential part of its cycle of metamorphosis — is in the main equally constant and fixed. Created by what even modern science must be content to own as a miracle, in the strictest sense of the word, it seems not improbable tiiat animal, as well as vegetable life, is sustained in consonance with some vast law of this kind. According to such a law, each by each, and both together, would make up certain constant units ; the innumerable constituent fractions of which might vary within vast limits without ex- ercising any effect on their respective sums. And thus the world of life around us would but parallel that perpetual flux, but un- altered quantity, which the chemist has long predicated of the various materials which compose the inorganic globe we inhabit. But if, on the one hand, the animal is in- capable of constructing its complex tissues from the simple elements of inorganic nature, still, on the other hand, it is not bound down by such rigorous chemical necessities, as to demand a food possessing an exact identity of composition with itself. A large propor- tion of the animal creation feed on a vegetable diet, the constituents of which deviate con- siderably from those of their own mass. And but very few of even the more carnivorous animals are in the habit of devouring their own species. Finally, though the blood forms the pabulum of all the tissues, and hence closely approaches their total composition, still it does not appear to form even an advantageous article of food, far less an indispensable one. And while such considerations may suf- fice to show, that there is no true identity be- tween the food and the tissues in general, the progress of modern physiological chemistry plainly indicates, that an identity of this kind would be equally impossible in detail. Thus it is not improbable, that the tissues of every individual possess chemical peculiarities more or less specific to himself. And it is all but certain, that the various proximate principles isolated by the chemist are not definite com- binations of certain elements in equivalent proportions — as are the salts, acids, and alka- lies of the inorganic world — but rather ever- varying mixtures. Those various forms of protein which it is so convenient to distinguish by the names of albumen, fibrin, and casein, may indeed be separated from the tissues of animals, and even of vegetables, by the same rough processes ; and may therefore respec- tively exhibit the closest resemblance in their composition and properties. But an accu- rate analysis would probably show, that the organic substance represented by either of these terms is never precisely identical in any two specimens. It is the total of a number of constituents, the result of a variety of pro- cesses, the end of a serial metamorphosis : rather than a definite and specific compound of carbon, oxygen, hydrogen, and nitrogen. And not only is there no identity in the composition of the organism and the ingesta, but It would seem that there are some tissues of the body which have absolutely no repre- sentative in the food : no kindred substance to which their formation can possibly be referred. Such are the various tissues that yield gela- tine ; a substance which, though it appears to escape assimilation when introduced into the organism from without, is yet constantly formed within it, from the metamorphoses of other parts of its substance. The chemistry of nutrition therefore implies neither construction, on the one hand, nor identity', on the other ; but something mid- way between these two extremes. Its forces occupy, so to speak, a debateable ground between the prehension of old materials, and the formation of new ones. And the food submitted to its action is only required to possess such a similarity of composition with the body, as will concede these limited changes, without implying any wider process of metamorphosis. Any exact definition of the degree of re- semblance thus requisite, would be foreign to our present object. Indeed, in the existing state of our knowledge, it is impossible to specify the precise nature of those metamor- phoses, which accompany the digestive act, and are bounded by the food and the organ- ism as their respective beginning and end. It is enough to indicate, that they appear to be intermediate between the forces of die- 384. STOMACH AND INTESTINE. mical affinity on the one hand, and homoge- neous and heterogeneous adhesion on the otlier; and that while they are sometimes * akin to the formation of hydrates, they oc- casionally resemble those still more recon- dite phenomena which are concerned in the production of isomeric or isomorphous com- pounds : — substances which, though identical in tiieir composition, offer striking differences in their solubility, as well as in many of their chemical properties and reactions. This very limited convertibility of the main components of the food, renders their variety almost as essential, as though each different tissue of the body had required the entry of its corres[)onding substance from without. In other words, within the range of the chemical parallelism just mentioned, the organism de- mands alimentary compounds containing all the different ingredients necessary to cover its own waste. This fact receives a good illustration from that selection which the instinct of most per- sons wouhl impel them to make. Lelt to himself, Man always chases a mixed diet, comj)Osed of proper quantities of animal and vegetable, liquid and solid, matter. Nay more, that almost equally imperious instinct which urges him to vary his diet, though often con- fused with the morbid cravings of luxury, is essentially nothing less than an expression of the natural wants of a healthy organism. Obscured, however, as these really natural instincts often are by the stereotyped tastes and habits of a highly artificial state of society, we gain a far better insight into the proper composition of food, by examining that store of nutriment which, in the shape of the yolk of the Bird’s egg, or the milk of the Mammal, Nature herself provides for the maintenance of the young of these classes. Of these two substances, the milk is Justly regartled as forming the very best example of a proper food : — both as regards the nature of its several ingredients, and the proportions in which they are mingled with each other. Milk. — The alimentary properties of the milk are due to the presence of a number of proximate constituents, the more impor- tant of which may be enumerated as fol- lows.— (1) A protein-compound, casein; (2) a hydro-carbon or fat; (3) a hydrate of carbon or sugar; (4) certain salts; and (5) the water in which the whole of these materials are suspended or dissolved. Of these five groups of substances, at least four are indispensable ingredients of every proper food. The hydrate of carbon and the hydro- carbon are, to some extent, capable of forming substitutes for each other. But with this ex- ception, (an explanation of which will be attempted by and by), the absence of any one of these constituents, or even its presence in insufficient quantity, suffices to destroy the capacity of any particular food for maintaining life ; so that an animal limited to such a diet * Compare tlie remarks on the gastric juice at p. .937. ultimately dies with appearances of inanition. And d fortiori, the ingestion of but one of these alimentary ingredients, — such as albu- men, fat, or sugar, — is soon attended with effects which still more closely resemble those of starvation. Such a diet does indeed essen- tially starve the entire organism, even while it supijlies some of the constituents of its lost substance. For although the unchecked waste of the remaining constituents of its mass tells upon certain of its textures with greater rapidity and energy than on others, still it ultimately involves the whole in a common destruction; — a fact which need little surprise us, when we recollect the mixed composition of the simplest tissues, and the intimate mutual dependence of the most distant and isolated parts. Constituents of food. — 1. The first group, consisting of what are called the protein- compounds, includes a number of proxi- mate principles, which are derived from both the animal and vegetable kingdoms of nature. The chief of these principles are albumen, fibrin, and casein. By digestion in solution of potash, and precipitation with an acid, either of these j ields a substance called ])ro- tcin : — a name that alludes to the relation this principle is supposed to bear to all the compounds from which it is thus obtained. It is regarded as their common starting-point {it(HiiTti)u),riuciples, however various their physical properties, have nevertheless the same chemical composition. And many of them are easily converted into grape sugar ; cither by the excitement of a limited meta- morphosis by an azotizetl ferment, or by expo- sure to the action of dilute acids. The sugary ingredient of the milk forms about i)er cent, of its quantity ; and is the only representative of the hydrates of carhon whicli it contains. The average amount of the substances belonging to this and the preceding group of alimentary constituents will of course vary greatly in the difierent kinds of food. Sjjeaking generally, however, these two groups may be stated to predominate by turns in the food derived from the two kingiloms of nature. Thus while the hydro- carbons are chiefly derived from the fat of animal food ; the hydrates of carbon belong even more exclusively to the starch and sugar of vegetable food. But, in strictness, no such marked difference can actually be made out between the two kinds of food in this re- S])ect. The milk, the liver,and even the blood of the animal, all contain sugar ; while inosit, a substance closely allied to sugar, forms au im- portant constituent of its various muscles. And not only do many |dants contain large quan- tities of oily matter stored up in various parts of their tissues, but even the seeds of thece- realia, which form the best vegetable diet, present an amount of fat ranging from '2 to 2 per cent. The purposes fulfdled by these hydrates of carbon in the animal economy, offer a marked contrast to those subserved hy the two pre- vious groups. The protein compounds form what is eminently the basis of the organism; — the [jlasma from w hich are developed the blootl and the tissues. They are thus his- fogcnetic and hannagcnetic, as the phrase is. The fatty matters of the body not only form a large constituent of the active nervous sub- stance, but are also retained and stored up in the more inert and passive form of adi- pose tissue. While the grape-sugar, into which the various hydrates of carbon are all finally converted, appears never to assume any permanent form in the body', but to he always rapidly eliminated from the blood. In wdiat shape, or after wdiat metamorphoses, it leaves this fluid, is at present uncertain. It - is, however, probable, that like the hydro-^^- carbons, these hydrates of carbon are essen-Ai^ .i 387 STOMACH AND INTESTINE. tially a species of fuel for that process of calorific combustion, which pervades the whole body, and which discharges its resulting car- bonic acid by means of the respiratory func- tion. And Liebig has adduced numerical data from the fattening of animals, which lead him to suppose, that these substances are also capable of undergoing a process of de- oxidation, that converts them into fat, and thus enables them to augment the adipose tissue. But this view rests on very insuf- ficient foundations*: and is curiously con- trasted with that oxidationf of hydro-carbons into sugar, which the researches of various recent observers seem to indicate as one of the chief functions of the liver .t 4. The importance of the water of the food is such as justly entitles this liquid to the rank of a fourth alimentary constituent. For it forms about four-fifths of the entire corporeal mass : and undergoes, at the va- rious excretory surfaces of the skin, the lungs, and the kidneys, a continual expenditure ; the replacement of which is obviously neces- sary to the maintenance of the proper com- position of the body. The way in which this large aqueous con- stituent facilitates the action of the various organs is not very difficult to conjecture. Their merely physical properties of hardness, flexibility, and the like, often seem chiefly determined by the quantity of the watery in- gredient which they contain. And their far more recondite vital properties seem quite as immediately under its influence. Thus not only do its solvent powers appear to be eminently useful in furthering the minute division, and the local transfer, of various organic substances, but we are justified in conjecturing that it gives a more specific chemical assistance to many of those pro- cesses of metamorphosis which are so inti- mately connected with life. In both of these respects, it would seem to afford a special aid to the function of digestion. While that act * The increase of fatty matter supposed to have been derived from these hydrates was calculated by subtracting the fat added in the vegetable food from the increase of the animal’s weight ; — this sur- plus being set down as due to augmented adipose tissue. Hence any error in estimating the fatty con- stituent of this food, on the one hand — or any neglect to calculate the watery and proteinous constituents of the increased adipose tissue, on the other — w'ould partially’ account for the difference observed. And it seems not unlikely that both of these inaccuracies actually occurred in these observations. t Assuming that such a metamorphosis really obtained, it would not be difficult to explainmostof Liebig’s results. For it is surely not impossible, that the presence of an excess of sugar in the liver might diminish the energy of this act ; in other words, that an excess of the product might lessen the activity of the process. Thus the copious in- gestion of sugar might check its formation, and diminish the metamorphosis of the fat supplied to the liver in the portal blood. And this retention of the fatty form might not only affect the hydro- cwbons of the food, but also those which are pos- sibly developed in the organism from its own pro- teinous constituents. t Compare the remarks on the liver, at p. 401. of absorption, which conveys the dissolved contents of the alimentary canal into the surrounding veins, is greatly facilitated by the heightened diffusive energy which the low specific gravity of water enables it to impart to the fluids with which it has been mixed. And finally, the use of water in relation to the opposite extreme of nutrition — namely, to excretion — may be well exemplified by the urine, in which a highly poisonous product of life is continually washed out of the system, through the instrumentality of a stream of this universal solvent. The details of death by thirst afford a fearful commentary on the above remarks ; — although, from reasons which will presently be mentioned, it will be obvious that even these cases rarely afford us true examples of the strict exclusion of all entry of water from without the body. After a period of ago- nizing thirst, the most distressing symptoms of which seem to be referred to the dry and inflamed throat and fauces, the deficiency of water is gradually revealed by a diminution — which is almost a suppression — of the various secretions that normally contain a large pro- portion of this liquid : namely, the sweat, the urine, and the faeces. Increasing muscular debility accompanies this change ; and is soon followed by delirium and coma, ending in death. And, conversely, the benefits afforded by water seem to receive an almost paradoxical illustration from its effects in the opposite states of starvation and of fattening. Thus, as regards the latter process, animals are stated to fatten much more easily and quickly when allowed the free ingestion of this liquid. And Becqiierel and Lehmann state, that when water is taken in excessive quantity, an in- creased amount of urea is excreted from the system of the healthy human subject.* While the researches of Bidder and Schmidt-f- show that, even after the withdrawal of all other ingesta, the copious use of water con- cedes to the starving animal a longer dura- tion of life; — diminishing, not only the waste of its protein compounds, but those collateral results of the vital processes, which are ex- emplified by the excretion of urea, carbonic acid, and salts. Hence water, which forms about 85 per cent, of the milk, is a universal constituent of the food of animals; and varies only in the proportion which its amount bears to that of the solid ingredients mixed with it, or dis- solved in it. In some of the lowest forms of animal life, its relative amount is so great, that the remainder of the food is only present in the state of a ver}' dilute solution. In cer- tain aquatic creatures of this kind, the medium around the animal seems to form a dilute alimentary solution, which only requires an act of absorption by the outer surface of its body. And even in the higher animals, in whom the other alimentary constituents are * An effect which is probably due to its favouring- the absorption of a larger quantity of protein from the same amount of food. t Op. cit. p. 34L C c 2 388 STOMACH AND INTESTINE. alwaj's taken into a stomach, or internal ca- vity, part of the total quantity of water which really accompanies them into the system is often intrmlucecl by the same mode of absorption. So that, although the amount of water consumeil by the organism has pro- bably a definite relation to tlie activity of tlie vital processes, the amount of tliis li<]uid habitually swallowed by any animal is greatly affected by the quantity introduced in other ways : namely, by the proportion contained in its solid food, the amount formed by the combustion of hydrogen in its body, and the quantity absorbed by its skin from the vaporous or liquid water of the surrounding media. Thus the ai)parently dry food of many herbivora is explained by the large amount of water, which is present as a chemical con- stituent of such food, and which accompanies its few digestible parts into the system. And the small amount of drink taken by many of the Batrachian reptiles is chiefly due to the active tegumentary ingestion last alluded to. The quantity of water contained in the va- rious kinds of food ordinarily made use of, will be referred to hereafter. But we may probably fix its average at about 75 to 80 per cent, (or about 5 lbs.) of the mixed fluid and solid food (about C'5 lbs.) of the human subject. 5. The salts of the food constitute the fifth and last group of its constituents, and that of which we may be said to know less than any of the others. For, while many of the more important are easily recognized in the ashes of the various fluid and solid aliments in which they are usually introduced into the body', still we are often at a loss to know the precise state of combination in which they are originally present in the food, far more that in which they enter into com- bination with the organism itself. In the case of many salts, we can, indeed, trace the actual changes of composition which occur in the organism. Thus the salts composed of the various organic acids united with the alkalies, are converted into car- bonates, prior to their dismissal from the body in the urine. And it seems possible that even the sulphates are occasionally decomposed in the alimentary canal ; their sulphuric acid being deoxidized into sul- phuretted hydrogen, while their bases unite with the carbonic acid formed in the system. Hence, although a careful and repeated ana- lysis of the salts contained in the organism and in its total excretions, might afford some clue to the qualities and quantities of the salts which ought to be introduced in the food, it would not by any means represent the details of these demands. While it is hardly necessary to add, that no such series of examinations has ever yet been made ; and that, however carefully conducted, it might easily overlook very small quantities of im- portant ingredients. Many discrepancies, however, it would probably clear up ; such as why animals which in one region seem indifferent to salt, in others seek it with the greatest avidity ; — why the diet which pro- duces scurvy in one person, leaves another little affected ; — and finally, why the roving population of the .South American Pampas can maintain a robust health on the fresh meat of the wild cattle which range these plains, while an apparently similar diet on the flesh of tame cattle has been known to destroy English soldiers. The more essential salts of the food seem to be the chlorides and phosphates of the alkalies ; and especially, the chloride of so- dium, and the phos[)hate of soda. Lime and iron arc also important bases. All of these ingredients are present in the salts of the milk ; together with some free soda and potash, which are probably combined with its casein. The phosphates are in large quantity ; espe- cially the phosphate of lime — the predo- minance of which is doubtless connected with the exigencies of ossification in the foetus. A Varieties of food. — The above grouping of the various constituents of the food, will afford us a valuable clue to the composi- tion of its principal varieties. For however widely these varieties may differ from each other, they always contain representatives from each of the preceding classes. And the best food for any particular animal will always consist of such a proportion of all these con- stituents, as best corresponds to the demands made by the waste of its whole body, and to the peculiarities of its organs of digestion. The food most natural to Man is a mixed diet. But though thus far omnivorous, he readily adopts an exclusively animal or vege- table food, according to the circumstances in which he is |)laced. And there are probably but few of the carnivorous and herbivorous animals, most properly so termed, in whom careful experiments would not detect a simi- lar, though scarcely equal, capacity for such a change of diet. Thus the herbivorous Horse and Cow may be brought to eat fish and flesh ; and the carnivorous sea-birds can be gradually habituated to the far more diffi- cult change implied in their feeding on grain. But many of the frugivorous Quadrumanaseem little susceptible of such alterations of diet. While there seem to be numerous Insects, which are not only strictly limited to a vege- table food, but even to certain species of plants, or particular |)arts of their structure. The influence of any S|)ecial variety of food on the human organism de|)ends chiefly on its physical and chemical [)roperties : — in other words, on its mechanical arrangement and admixture ; and on the constituents w'hich it ])resents ; either originally, or as modified by the operations of cooking. Hence these are the chief points which will be noticed in the following short description. It is obvious that the division of the various alimentary substances into solid and liquid, or food and drink, is an incorrect one. For, on the one hand, even the driest articles of solid food contain a large proportion of water of composition. And conversely, the purest liquids ordinarily made use of contain a certain quantity of solids, in the shape of STOMACH AND INTESTINE. 389' cHssolved salts, which are by no means in- diiferent to the organism. In the following cursory view of the ordinary articles of diet, we shall begin by contrasting the general characters of animal and vegetable food. We shall then sketch the chief va- rieties of each generally made use of. And, finally, we shall attempt to estimate the pro- portions of each contained in a suitable die- tary of ordinary mixed food. it is to animal food that we must on the whole assign the first rank as an article of diet. For not only do the tissues of one animal necessarily contain most, if not all, of the organic and inorganic substances required for the construction of another, and in some- thing like the proper proportions of their respective ingredients, but they are generally devoid of all noxious constituents. Besides these advantages, they otfer the equally im- portant ones of possessing such a structure, arrangement, and solubility, as materially aid their entry into the organism. Hence they are not only much more nutritious than an equal quantity of vegetable food, but are also di- gested and assimilated with far greater ease and rapidity. It is for this reason that the use of animal food is so much to be preferred in all circumstances where it is our object to avert the speedy exhaustion of the vital powers. Against these advantages, possessed by animal food, we must, liovvever, set oft’ the disadvantages, that it not only contains some substances which (like gelatine and the horny tissues) appear to be either useless or even to require a .speedy excretion ; but that, as a rule, it is deficient in those non-azotized elements, which are so important to the main- tenance of the combustion anti heat of the organism. For the limited quantity of fatty matters which it generally includes rarely suffices to make these hydrocarbons a proper substitute for the copious amylaceous and saccharine constituents of vegetable food. The main disadvantages of vegetable food are equally obvious. It generally contains but a small proportion of the protein com- pounds. And even this limited quantity is often virtually diminished by their insoluble state ; or by the indigestible form which is implied by their mechanical arrangement in the vegetable tissues. Many of its amyla- ceous constituents are also rendered useless in the same way : being enclosed in insoluble envelopes, which effectually sliield them from the digestive process ; or having a composi- tion which requires to be altered by a chemi- cal metamorphosis before they can be fitted for ab.soiqition. These objections can be to a great extent obviated by the ingestion of a larger quantity of such food, as well as by a more protracted sojourn in the alimentary canal. But, besides these disadvantages, the inorganic constituents of certain kinds of vegetable food appear to be insufficient for the replacement of the loss consequent on the waste of the animal. Thus the ash of many esculent vegetables is peculiarly deficient in the important ingredients of soda and the chlorides. The poisonous materials con- tained in the tissues of some plants constitute another objection to vegetable diet ; — an objection which is, however, generally ob- viated by the instinct of animals, and by the experience of Man, or by the purification which the process of cooking often aflbi’ds. Animal food. — The muscular substance, accompanied by more or less of its intersti- tial and investing fat and areolar tissue, forms what is called meat or flesh, in the ordinary acceptation of these words. The mechanical subdivision of a mass of meat would of course afford us the micro- scopic elementsof the above tissues;— namely, sarcolemma, sarcous substance, white and yellow fibrous elements, fat, and blood vessels ; together with a certain quantity of blood, and of the nutritional fluids which sa- turate each of these textures. Its chemical composition varies, not only" with the nature, but also w'ith the age, food, habits, and indi- vidual peculiarities, of the animal yielding it. Hence it is impossible to give any definite account of its quantitative chemistiy. We can only enumerate its principal constituents ; and, in the case of some of the more im- portant of them, approximatively estimate their amount. The protein-compound, that forms by far the greater part of the mus- cular fibres, is a substance which possesses characters closely' allied to those of fibrin, and has received the name of syntonin. It is usually present in a proportion of, about 15 or 10 per cent. The albumen of the juice which soaks the whole muscular mass, and the gelatin w'hich is extracted from it by boiling, may each be estimated at about 2 per cent. Its extractive, exclusive of salts, amounts to about 3 per cent. ; of which nearly half is dissolved by alcohol, half by water. This constituent has a very complex composition ; osmazom, lactic acid, inosit, kreatin, kreatinin, and a variety of other substances, having been detected in it by the labours of modern chemists. The salts of meat form about 1 j per cent, of its fresh substance, or about 5 per cent, of its dried mass ; nearly three-fourths of their quantity being phosphates of the alkalies, and two-thirds of the remainder phosphates of the earths, with a little iron. The chlorides of the alkalies are about one-fourteenth of the entire ash. They are remarkably contrasted with the chlorides contained in the ash of the blood, by the great proportion which the chloride of potassium bears to that of sodium. It is impossible to estimate the quantity of fat contained in meat as usually eaten. But even after the removal of all visible adipose tissue, Von Bibra has found fractions ranging from one-twentieth to one-fifth ; the smaller amounts corresponding to the flesh of the Hare and Deer, while the larger (in the beef of Oxen) were perhaps partially due to a more or less artificial fattening. The flesh of Birds contains less water and fat, and more albumen, syntonin, and kreatin, than that of most of the Mammalia hitlierto c c 3 390 STOMACH AND INTESTINE. examined. The muscular substance of Fishes contains a still greater quantity of albumen. That of the young of most animals is softer, and its fibres smaller and more digestible, than the flesh of the adult. The artificial preparation of animal food for the table probably induces a variety of chemical changes. 13ut the full import of these changes has yet to be made out. At pre- sent, we know little except some of the more obvious physical results which attend the processes of cooking. These are best seen in the cooking of meat. The increased digestibility of meat which has been killed some time previously to being eaten, seems to depeml, partly on the more uniform and softer consistence imparteil by the difl’nsion of its juices, ami partly on the imperfect decomposition which it has begun to undergo. The latter change to some ex- tent prepares it for digestion, by remlering it more soluble. But any a|)proach to abso- lute putrefaction reverses this advantage ; — at any rate, in the case of Man, whose natural judgment would probably in most instances lead him to reject putrid meat, as alike dis- gusting to the senses, hurtful to digestion, and dangerous to health. In the operation of roasting meat, the heat applietl to the exterior of the mass soon con- verts its superficial portion into a dense, hard substance. This compact crust consists chiefly of albumen which has been coagulated by heat. It is of essential service, not only in mode- rating the heat afterwards applied through it to the deeper portions of the meat, but also in retaining its various liquid and volatile [iro- ducts, which would otherwise be soon dissi- pated in the gaseous or vajiorous form. The moderate heat which permeates the mass probably aids the various juices of the meat in diflusing themselves throughout its whole texture; increasing its uniformity of consist- ence, and dissolving much of its gelatinous tissues. Its albumen is always more or less coagulated by the heat ; though, where much blood is [iresent, the colour and fluidity which it sometimes retains, appear to indicate an imperfect character of this change.* A variety of empyreumatic substances, which are de- veloped chiefly in the more heated exterior of the mass, next add the savoury odour and deepened colour, so characteristic of this method of cooking. If the process be unduly protracted, it will obviously burn the harder outside shell, and render the coagulated and contracted mass within too dense, tough, and insoluble for easy dige.stion ; while, if con- ducted too rapi.lly, the same combustion of the outside is of course attemled with the loss of all the ailvantages of cooking in the raw central portion. The changes induced by boiling meat, * Tins imperfect coagulation has been supposed to pvov'e that the heat (154°) at which the blood coa- gulates, has not been attained. But the appearances in meat boiled at 212°, and the temperature of roast meat itself, render s.ich a view very doubtful. partially resemble those which are caused by roasting it. For both of these processes are probably accompanied by a coagulation of albumen, a solution of osmazom, and a formation of gelatine in the mass itself. But they differ greatly from each other in many respects. From the lower tempera- ture applied in boiling, no empyreumatic sub- stances are developeil ; while the water which conveys the heat to the mass always extracts from it a certain proportion of its soluble constituents. This extraction may be to some extent diminished by suddenly plunging the meat into boiling water, so as to coagulate the albumen of its outer- most layers ; and conversely, the extractive process may be favoured, not only by in- creasing the surface of contact, but also by delaying the coagulation of the albumen, and prolonging the period of the solvent action. Hence, where it is chiefly the broth or watery solution of the meat which is intended to be nseil as food, the mass is preferably cut in very small jfieces, and the tern[)erature of the water raised very slowly to a degree of heat short of ebullition, and maintained there for a long time. The various modes of salting and smoking meat are chiefly intended to protect it from decomposition ; hence they scarcely require much notice here. In the former process, however, the i|ualities of the meat appear seriously damaged *, quite apart from the mechanical disadvantages which both it and smoking often impart. Fcit.—\n a purely animal diet, the amount of this oleaginous constituent is of indispensable importance. For, with the exception of that minute quantity of inosit or muscular sugar which is proper to the sarcous substance, the fatty matters contained in the various tissues of the body are the only representatives of the two groups of the hydro-carbons and hy- drates of carbon, which this kind of food possesses. Hence the fat of such a diet has to replace, as it were, the starch of the vege- tables which usually enter into a mixed diet ; and thus constitutes the sole non-azotized or respiratory element of animal food. And even in what are often miscalled vege- table diets, a large quantity of this animal sub- stance is commonly ailded to the other ingre- dients of the food. At least there seems to be a strong impulse towards such an admix- ture in most of the vegetarian nations and races of modern times : — an impulse which is well exemplified in the butter or ghee so copiously added by the Hindoo to the rice that forms his staple food. The quantity of fatty matter which may thus be taken into the system can scarcely have any definite limit assigned to it. In the Arctic climates it appears to attain a very * The liability of persons fed on such meat to scurv}', can scarcely be exclusively referred to the privation of vegetables. For large numbers of people appear to subsist with impunity on fresh meat only (see p. 388.). STOMACH AND INTESTINE. 39i large proportion. And it is impossible to avoid connecting this maximum of fat in the food, with the large amount of lieat that has to be evolved from the body in these cold regions, as well as with the energy of tlie combustion on which this evolution of tem- perature depends. As a rule, however, but a small quantity of fatty matter can be really digested at a time. Any excess over this amount is merely expelled from the intes- tinal canal with the faeces. The digestibility of fat depends chiefly on two circumstances : — its mechanical arrange- ment, and its chemical composition. In tlie adipose tissue, the fatty substances are en- closed in large nucleated cells ; the membranous walls of which consist of a proteinous sub- stance that is rather difficult of solution, and yet requires to be dissolved before its contents can enter tbe lacteals as chyle. And the three substances (stearine, elain, and marga- rine), which form the greater part of the fat of the Mammalia ordinarily slaughtered for food, possess very different degrees of solu- bility. Hence they are by no means equally easy of digestion; the first resisting its in- fluence much more obstinately than either of the other two. An animal which is fed exclusively on fat increases in size during a short period. Its nutrition, however, soon suffers ; and it finally dies, with those appearances of inanition which have already been mentioned as attend- ing all attempts to maintain life by the in- gestion of only one ingredient of the normal food. In the later stages of this process of starvation, its body gives off a repulsive odour, which appears to be due to the evolution of volatile fatty acids from the skin and lungs. The production of these acids may be re- garded as probably due to an imperfect oxida- tion of the hydro-carbons accumulated in the organism. The alimentary properties of various other tissues and organs of the animal body may be passed over w ith a vet’}' brief notice. The blood itself appears to be a far less valuable article of food than its composition would jead us to suppose; — abounding, as it does, in the important protein-compounds of fibrin and albumen. Some authors have supposed, that its digestion is rendered diffi- cult by the dense state of aggregation which its fibrin is so a[)t to assume in the act of coagulation. But however this may be, still its large albuminous constituent appears to be m a condition such as would eminently fit it for fulfilling the requirements of the organism. We are thus left to remark upon its almost total want of hydrocarbons*: as well as upon the contrast offered by its salts f to those of the muscular substance. _ The brain and nervous centres are so rich m albumen and fat, as to form highlj' nutri- tious artides of food; especially when they are mixed w'ith other substances, which are more * See p. 38G. of this article. t Compare pp. 332. and 389. capable of affording the requisite mechanical stimulus to the digestive organs. The various glands possess a dietetic value which is derived, partly from their physical structure and arrangement, partly from their chemical composition. Thus, the dense mechanical texture of the liver and kidney must decidedly oppose their usefulness as food : while the bile and urine which they respectively contain, necessarily superadd the properties of these secretions to those of the proteinous parenchyma that forms the bulk of their mass. And conversely, from both mechanical and chemical reasons, the pancreas is highly digestible and nutritious. The hard solid texture of bone, and its large gelatinous and calcareous constituents, to- gether render it of comparatively little use as an article of food. The eggs of oviparous animals contain, in addition to the embryo itself, a quantity of nutritive matter, which is destined for its nou- rishment during the process of incubation. Hence, the large eggs of many Birds form an excellent article of food, the dietetic virtues of which resemble, to some extent, those pre- viously attributed to milk. The white of egg contains about 15 per cent, of albumen. The yolk is composed of about 20 per cent, of the same protein compound ; together with about 30 per cent, of fatty matter — chiefly margarin and elain — in a state of subdivision and ad- mixture which eminently adapt it to digestive purposes. The general composition of the milk which forms the food of young Mammalia has already been mentioned. It only remains for us to notice its chief varieties, and the products which its artificial preparation adds to the bill of fare of the adult. The peculiarities exhibited by the various kinds of milk, are chiefly referrible to the species of the parent animal, the date of its lactation, the nature of its food, and its habits. Thus the milk of the Human female* contains about half the quantity of casein, and two-thirds the butter, of that of the Cow: while that of the Ass, which is still poorer in each of these constituents, greatly surpasses them both in the amount of its saccharine ingre- dients (being as 3 to 2). The rich colo- strum which is yielded in the puerperal state f soon gives place to a milk which is * From some analyses of this secretion, in two persons, L’lleritier concludes that the milk of Bru- nettes contains nearly twice as much casein, as that of Blondes; together with about one-half more butter, and one- sixth more sugar. This statement con- firms a belief generally entertained as to the superior qualifications of women of dark complexion as nurses. But, without much more extensive observations, it cannot be accepted as an established fact. If true, it would remarkably complete what rve may venture to call the structural and functional homologies of the mammary gland, all of which concur in regarding it as a highly-developed offshoot of the general integuments. f The composition of the colostrum seems to in- dicate, that it is partly derived from milk ivhicli has been concentrated in the breast subsequently to its secretion, by the re-absorptioii of a portion of C c 4 STOMACH AND INTESTINE. 392 poorer in all llie solid ingredients : and the iurther continuance oflactation appears cliiefly to increase its casein anil salts, and diminish its sugar. The copious ingestion of fatty or starchy substances seems to increase the buttery constituent. The over-feeding of a wet-nurse causes her to secrete a miik abnor- mally rich in butter and casein, and injurious to a delicate child. Finall)', vigorous exercise appears to diminish botli tliese constituents, especially the former. Butter. — The composition of the butter contained in milk is as yet but imperfectly known. That of the Cow is stated by Bronieis * to consist of about C8 per cent, of margarine, with 30 of elain, and 2 of fatty matters specific to butter. The exact nature of the latter constituents probably varies in different animals, as well as in different sjieci- mens of the secretion ; and also seems very liable to be altered by that rancidity which butter so easily acquires from a short exjio- sure to the air. Such circumstances quickly give rise to the formation of a variety of vola- tile fatty acids : — which are known under the names of butyric, caprylic, capronic, capric, and vaccinic acids. The dietetic value of butter can scarcely be rated too highly. It is probably by far the best and most natural form in which hydro- carbons can be suj)[)lied to the healthy organ- ism. It is not only attractive to the taste, but is easily assimilated : — even by children or adults, whose delicate digestive organs resent the introduction of the ordinary adipose tis- sue ol animal food. The quantity which may be advantageously consumed will of course var}- with the nature and amount of other food, and with the rate at which combustion proceeds in the body. But the very large amount of this substance habitually consumed b}' the Hindoos, and by the dairy-men in many of the Al[)ine highlands of Europe — in the latter case often reaching a pound daily — is a striking testimony alike of its harm- lessness to the digestive organs, and its value to the system generally. Cheese. — The substance known by this name consists chiefly of casein ; which has been precipitated from the milk in company with a variable quantity of its buttery con- stituent. Its dietetic value is of course very high. But its digestive properties vary greatly; according to the proportion of fatly matter and salts which it contains, the mechanical aggregation of its mass, and the degree of decomposition which it may have experienced. Thus as regards its admixture of butter, we may di.stiuguish three varieties of cheese : — one which is made from cream, or from milk with the addition of cream ; one from pure milk; and one from milk which has been skimmed or deprived of its cream. its watery ingredient. This view is corroborated by the fact, that colostrum-corpuscles have been found in the niilkj' contents of the male breast. * Annalen der Chem. und Pliarm. lid. xlii. s. 4G. et scq. In respect'to its salts, the chief distinction hitherto established appears referrible to the way in w hich the casein has been precipitated from its solution in the milk. Where the process has been effected by the addition of rennet, the caseous deposit contains a large proportion — about 3 or 6 per cent. — of phosphate of lime. But where the precipita- tion has been produced by the lactic acid which is gradually developetl in milk as the result of its own spontaneous decomposition, the dejiosit contains scarcely one per cent, of this salt. In such a case, how'ever, the smaller amount of phosphates appears to be partially compemsated by the presence of some free phos[)horic acid. The changes which cheese undergoes by keeping are chiefly manifested in the I'orma- tion of various volatile fatty acids, that gene- rally communicate their characteristic odour to the whole mass. Such alterations are usually most marked in those varieties of cheese, in which but a small proportion of rennet has been used, and much fatty matter is present. Hence they seem at least par- tially attributable to a metamorjihosis — pro- bably an oxidation — of the buttery con- stituents themselves. In addition to this change, however, the casein also undergoes a somewhat similar fermentation ; which is ac- companied by the production of oxides of casein, and volatile fatty acids. Occasionally the process is carried so far as to constitute a kind of putrefaction, in which the nitrogen originally present is given off in the form of ammonia. The highly poisonous properties which decayed cheese sometimes possesses, and the repulsive odour which it often gives offj may illustrate these statements. The value of cheese as an article of food may be to some extent inferred from the large amount of its proteinous constituent, which often forms more than 70 per cent, of its whole weight. This quantity of casein would corresiiond to about 1 1 1: per cent, of nitrogen : a quantity far beyond that contained in any other ordinary variety of azotized food. But just as this unexampled chemical com- position may suffice to indicate how largely such a [iroportion of the “ histogenetie” prin- ciples would require to be diluted wdth the “ respiratory ” or “ combustible” substances, in order to constitute a food in the true accep- tation of the term, — so it partially explains the fact, that cheese is anything but ea.sy of digestion. With many persons even milk is only digested with difficulty; so that much of its casein may be traced through the bowels, but little changed by the action of tlic gastric juice. And the mechanical aggregation of many kinds of cheese — their extreme hard- ness, dryness, and densit}', — often enable them almost to defy digestion. But minute divi.sion, cooking, or careful mastication,will obviate one of these objections ; and the other is easily met by a proper admixture of vegetable food. With such [irecautions, cheese becomes a most valuable article of food. So that we need be little surprised to find the extreme STOMACH AND INTESTINE. 393 value and importance assigned to this variety of azotized aliment amongst rural populations where meat is scarce and expensive. Indeed, the diet on which tradition states old Parr to have attained his remarkable age can hardly have been very unwholesome. And the natives of a country which, like ours, still boasts of large cheese-fairs in some of its country towns, can find little to wound their national pride in the quaint fancy of Mueller : — that cheese and freedom flourish together. Vegetable food — The general characters of vegetable food have already been alluded to. They are, however, modified by all cir- cumstances which materially affect the ar- rangement or composition of the vegetable tissues. Thus young plants, or the younger shoots of plants, are much more easily digested than the harder and less soluble textures of the older organism. While the approach of fruits towards their maturity determines a series of physical and chemical alterations, which have the result of rendering them much more nutritious. The mode of culture, and the peculiarities of the soil, also exercise im- portant influences on the resulting vegetable produce. Thus a rich soil, a warm climate, or a highly azotized manure, have all been noticed to increase the per-centage of protein contained in the corn grown under their in- fluence. And the influence of such circum- stances v/ill, of course, be in some degree extended to the persons and animals, whose staple food is thus partially dependent upon them. Corn. — The seeds of the cereaUa are not only the most important of all the varieties of vegetable food, but may even be ranked above all other alimentary substances, animal as well as vegetable. The history of mankind suffi- ciently attests the truth of this estimate, — an estimate which is confirmed by the appel- lation of “ the staff' of life,” that is applied to their chief product as prepared for food. An inquiry into their composition explains this remarkable value, by showing that the nutriment which such seeds place at the dis- posal of the vegetable embryo they contain, has a close resemblance to milk, both in the number and proportion of the alimentary principles of which it is composed. The y that slow metamorphosis, which dense starchy substances would here continue to undergo. But in animals like the Horse, whose aliment passes quickly through the stomach and small intestine into an enormous colon, it is difficult to avoid believ- ing, that a more or less modified gastric juice accompauies the insoluble albuminous com- pounds of the food into this segment of the canal, and continues its solvent action during their long sojourn in its interior. It would otherwise be almost impossible to explain the nutrition of such animals. How far the large intestine can take up fat remains un- known. But it seems certain that its share in the absorption of this alimentary principle is very slight compared with that of the small intestine. The entire process of digestion might there- fore be described as consisting in tlie apjilica- tion to the food of a variety of agencies, such as mechanical division, solution, and metamor- phosis. In whatever manner these are ap- plied (eitlier to the food as a whole, or to the several alimentary principles which form its constituents), and whether they operate in suc- cession or combination — in any case, they alt work towards the same object : namely, that of preparing the food for absor[)tion by the vessels and lacteals which occupy the walls of tile digestive canal. With this act of ab- sorption, the function of digestion terminates. The cliief agents of this process of division and solution, we have found to consist of certain liquid secretions ; which are poured into the canal, either by the ducts of several glands, or by the vast compound mucous mem- brane that lines the various parts of its cavity. In short, the food received into the intestinal tube, mingle.s with a large quantity of a mixed fluid ; wliich itself represents the aggregate contributions of the salivary glands, the pancreas, the liver, the stomach, and the__ in- testine. But the more accurate researches which have recently been made on the nature and amount of these secretions, confirm a suspi- cion that has long been entertained with respect to some of them by pliysiologists. Comparing tbeir quantity and quality with that of the faeces and the food, we can now confi- dently state, that but a very small fraction of their whole mass leaves the canal with tlie excrements ; by far the greater part of it being reabsorbed into the vessels of the ali- mentary canal. This proposition —so important to a cor- rect appreciation of the true office of the in- testinal canal, and of the relation of digestion to nutrition — has lately been placed in the clearest light by the admirable researches of Bidder and Schmidt upon animals. From their toilsome and accurate experiments, it would appear, that the total quantity of matter which thus leaves and returns to the cir- culation of an adult man, may be esti- mated at little less* than 20 pounds of liquid daily ; of which about 3 per cent, consists of solids in solution. The importance of these “recrementitious ” secretions to the system, is w-ell shown by the results which follow the establishment of an artificial biliary fistula. Unless the ensuing loss of bile is compen- sated by the digestion of a much larger quan- tity of food, the animal so operated on soon dies of inanition. And it is probable that the ex- haustion produced by diarrhasa, or by the discharge of the intestinal contents through an abnormal opening in the bowel, may be partially due to a similar loss of this and other rich organic fluids, which ought to be reab- sorbed. Whether the secretions experience any change prior to absorption • — whether any of them arc really modified, and thus far digested by their colleagues — remains at present in doubt. It may be conjectured, however, that they are so altered. At any rate, it would seem that, by provoking these secretions j-, the whole system of a starving animal may be for a time invigorated and restored. But the chain of these phenomena is at present too indistinctly seen, and their connection with various other organic processes much too obscure, to justify us in doing more than offer- ing this conjecture, as one of the most imme- diate explanations of certain well-known facts. But we know enough to state that, within the limits of ingestion and egestion, lie two corresponding acts of absorption and secre- tion. Each of these is, so to speak, the co- efficient of two elements. Absorption takes up food and secretions : secretion pours out, not only materials newly devoted to this purpose by the system, but others which have, in all probability, already subserved it many times before. The great mass of the intesti- nal secretions is thus continually revolving in a cycle : — forming a circulation the channel of which, placed in the intestinal canal, leaves and returns to the blood that flows in its walls ; and only allows a very small offshoot of its current to reach the outer world, bear- ing with it certain of its effete particles. The important chemical details of this cir- culation have yet to be won by sedulous and thoughtful “ questionings of nature.” But since, for the acquisition of such results, the liver offers what will probably be the easiest prize, it may be useful to point out how little even the vast progress of modern chemistry has hitherto been able to establish respecting its true physiological import. The portal blood, * Fi’om the greater proportionate waste of small animals, it is possible that this estimate (22 lbs. for an adult weighing 140 lbs.) is rather too large. t Some of the American Indians are alleged to eat clay with the object of alla3'ing hunger. The drinking of water is well known to have a similar effect, and has been shown to increase the quantity of these secretions without causing a converse dimi- nution of their density. And the benefit which a starving person derives from the minutest portion of food is sometimes so sudden and remarkable, that we can scarce!}^ avoid referring it to the same explanation. (Compare 1 Sam. xiv. 27. 29.) 40] STOMACH AND INTESTINE. charged with the water, fat, albumen, salts, and extractive, which it has taken up from the food, and from the secretions of the diges- tive organs, reaches a large gland. There it breaks up, as it were, into two streams of fluid: bile, and hepatic-venous blood. And hence, the composition of these two fluid products, compared with its own, might be expected to give us a clue to the process by which they originate, if not to the action of the secreting structure itself. Such an examination would show that the hepatic blood has lost almost all the fibrin, half the albumen, much of the water, and half the fat (even more of the elain) present in the portal vein. It has gained in extrac- tive, and especially (ten to sixteen times as much) in sugar. And its pale corpuscles are increased in number. On the other hand, the organic constituents of the bile are chiefly fatty substances, espe- cially the fatty cholic acid and its congeners. The quantity and quality of most of these sub- stances show that they have probably been formed in the liver : and hence that their pre- sence ill the bi!e is not to be explained as a mere transudation of certain dissolved con- stituents of the blood, followed by their con- centration in the gland, such as might be alleged in the case of most of its salts. But here for the present we rest. Sugar on the one hand, and certain fatty acids on the other, appear to be formed in the liver ; at the expense of fat, albumen, and fibrin. Until accurate quantitative researches establish whether the disappearance of the protein- compounds is sufficiently accounted for by the total increase of extractive and of pale corpuscles in the bile and hepatic vein, the exact source of these substances must re- main a mystery. Schmidt, indeed, suggests, that the fat of the portal blood is decomposetl in the liver into the sugar and cholic acid which its elements would exactly make iqi. But while we are justified in giving every consideration to a view which seems so con- sonant with the facts hitherto knowm, we must be careful to remember that it is on these facts, and not on the neatness of any formula, that its value entirely dcpends^ Un- supported by them, it would be a mere ar- rangement of certain letters and figures, de- void of all real significance, and destined to the oblivion to which thousands of its predecessors in the literature — not the science — of chemistry are daily being con- signed. Development. — The development of the alimentary canal, like that of other or- gans, offers a series of complicated changes, the details ofwhich often have but little visible or direct relation with the future function of the part. Hence any minute description of the process would be quite out of place in this essay. The author therefore limits himself to a brief sketch of its general outline ; and for all further details begs to refer the reader to the article “ Ovum.” Supp, Just as the completely developed intestinal tube might almost be described as the involu- tion of an extremely vascular cell-growth, so its origin distinctly refers it to those two genninal layers of the embryo from which such mucous and vascular structures are re- spectively derived. The centre ot the early ovum consists of three layers ; the upper or serous, the mitldle or vascular, and the under or mucous, lamina. A portion of each of the tw'o latter is folded inwards, to form the rudiment of the alimentary canal. And the whole history of the subsequent develo[)ment of this tube is little more than a recital of the various steps and processes, by which these mucous and vascular structures are so arranged as to result in the characteristic form, the nu- merous segments, and the complex structure, which have been briefly described in the fore- going pages. The formation of the tube begins by the separation of the united vascular and mucous layers from the serous lamina immediately above them. An increase of this separation prolongs their attachment to the serous layer into a simple and rudimentary mesentery. Each end of the canal is then mapped out, by the conjoined laminae being bent down- wards and inwards, so as to give rise to two shallow pits or fossae : which are named the fovea cardiaca, seu aditus ad mtesthmm ante- rior; and the foveola caudalis, seu aditus ad intestinuin jMsterior. These tw'o fossae, how- ever, do not correspond to the future mouth and anus ; but to the cardiac aperture of the stomach, and to the middle segment of the rectum respectively. And between them, a lateral inflection of the conjoined mucous and vascular layers gives the canal two sides, the lamincB intestinales ; which, like the similar vertebral plates of the serous layer, bound a shallow groove. This groove, the Jissura intcstinalis, is rapidly converted into a tube, by the closing in of its inferior or open surface. The process of closure begins at each ex- tremity of the groove, and runs rapidly to- W'ards its centre ; but is arrested here, so as to leave an opening or umbilicus, by means of which the intestine is connected with the umbilical vesicle that replaces the vitelline membrane and yolk. But there does not seem to be any direct continuity of the vitel- line and intestinal cavities with each other through the channel formed by this umbili- cal (“omphalo-enteric”) duct: — at least not such an aperture as to allow of the yolk itself being immediately received into the intestine. As the umbilical vesicle gradually removes from the intestine, this duct undergoes a cor- responding elongation. Its canal becomes obliterated prior to the degeneration and dis- appearance of the tube itself. The simple straight cylindrical canal, the development of which has thus been traced out, resembles the permanent intestinal tube of many of the lovver animals; with the ex- ception that, as above stated, it is deficient in both terminal segments. These it next ac- quires. And at the same time that it does so, U D 402 STOMACH AND INTESTINE. it assumes the length, form, and convolutions, proper to the perfect intestinal tube. As it already occupies the whole length of the abdominal cavity, any elongation of the canal will of course give it a curved shape. And since, at this period of foetal life, the abdomen opens by a wide vertical fissure in the situation of the future umbilicus, the first bend of the intestine renders it convex forwards, and then protrudes it through this aperture. Here it adjoins the base of the umbilical duct ; which opens into the point or angle of this convexity, so that the bowel appears like a bifurcation of the duct itself. The two forks of this bifurcation are soon producei-l into a spiral coil of intestine; which still lies outside the abdominal cavity, and only recedes into it at about the middle of the third month of uterine life. At this stage of its evolution, the intestinal canal may be conveniently described as con- sisting of three portions: an anterior, which extends from the beginning of the tube to the umbilical coil ; a middle, which is formed by this coil itself; and a posterior, wdiich reaches from the latter segment to tlie end of the canal. The anterior of these three portions may again be subdivided into three similar seg- ments. The first, which gradually elongates from the blind end that was formerly the fovea cardiaca, is developed diu'ing the evolu- tion of the thorax, so as to form the oeso- phagus. And it finally opens into the cavity of the mouth ; which is itself developed from an involution of the skin, and from the united ends of the anterior visceral arch. The second or middle segment dilates, turns on its left side, and then bends transversely to the axis of the body, to form the stomach. The pyloric valve is only visible some time after this change has occurred. And the third or lowest portion of this anterior segment is con- verted into the duodenum. The middle, umbilical, or extra-abdominal, part of the canal, is developed into the jeju- num and ileum, the ctecum, the vermiform appendix, and part of the colon. In this process, the change of form undergone by the small intestine is limited to a mere increase in its length and in the ilegree of its con- volution : — an alteration which is accom- panied by a further elongation of its mesen- tery. The upper boundary of the large intestine is first seen as a constriction and change of calibre, which occu[iy a point some distance below the insertion of the umbilical duct. Such a situation of the future ccecum conclusively shows, that the vermiform appendix is not that permanent intestinal end of the duct, which Oken supposed it to be. This commencement of the large intestine next enlarges into a projecting pouch of uniform width. But the lower end of this pouch soon ceases to enlarge, and remains as the vermiform appen- dix. While its upper part, increasing in size, becomes the ccecum. The valve appears at about the tenth week. But the proper shape and size of the ccecum are only acquired towards the end of fcetal life. The colon is developed from the lower part of the second, and the upper part of the third [)ortion of the rudimentary intes- tine. The ascending colon is at first a simple straight tube, which, commencing in the pouch just alluded to, runs forwards along the spinal column, lying to the left of the numerous coils of the small intestine. The succeeding backward bend of this tube has at first a median position, w'hich renders it par- allel with (and close to) the ascending colon. But this ])art of the canal soon elongates ; and, passing outwards towards the left side, forms the transverse and descending portions, as well as the sigmoid flexure, of the colon. Finally, the blind end which corresponds to the rec- tum is continually moved downwards by a gradual lengthening of the tube; so that it meets, and at last opens into, a cavity, which is sent inwards Ifom the skin to form the future anus. The sacculation of the large intestine only occurs in the latter half of uterine life. The valvulae conniventes appear still later, and are but rudimentary at birth. The develo[)ment of the various microscopic constituents of the canal may be almost as briefly summed up. The cell-growth (which is derived from the mucous lamina), and the fibrous tunic (which is developed from the vascular lamina), are at first very loosely united to each other. Hence they may be easily separated into distinct and comparatively plane strata ; of which the fibrous has about double or treble the thickness of the epithelial one. The cells of the latter affect an elongated or columnar form at a very early date of foetal life (about the sixth week). The various offshoots of tubes and other glands which are contained in the wall of the canal, are developed from a mass of cell- growth, which sprouts from the external surface of the mucous layer, and gradually acquires the definite form and cavitary ar- rangement specific to these minute structures. The larger accessory glands of the liver and pancreas are produced from a similar mass which lies external to the bowel : and they ultimately prolong their ducts so as to open into the cavity of the intestine. The fibrous layer, which is at first smooth and homogeneous, soon becomes roughened into little projections, which ultimately take the shape of conical processes. These, as they enlarge, pass upwards into the raucous or epithelial layer. Some of these projections not only separate the various tubes and glands from each other, but, by a further advance and enlargement, carry before them the general surface of the cell-growth. They thus form the future villi. While others — ■ and by far the majority — affect a lateral, instead of a vertical, growth ; uniting with their neighbours bj' cross ridges, which soon form a network, that extends between the tubes at all parts of their height, so as to constitute a matrix for these and the other structures derived from the mucous lamina. 403 STOMACH AND INTESTINE. Finally, the unstriped muscular fibres, and the white and yellow fibrous elements, repeat the ordinary steps seen in the development of these tissues generally. Ab.vormal Anatomy, Malformations. — The malformations of the digestive canal may be conveniently arranged in three groups: — 1. Those which appear to depend on an arrested or deficient de- velopment. 2. Those which are attended by an excess of size. 3. Those which can only be referred to errors of development, the causes of which are unknown ; or to mal- formations of adjacent parts. (1.) A deficient development of the whole lube may diminish either its calibre, its length, or both of these dimensions simultaneously. But malformations of this kind are rarely seen, in that marked degree in which alone they can be distinguished from from the differences which doubtless obtain in different indivi- duals. Among the results of a local failure of de- velopment, by far the most common is one, which we might expect to be so, both from the history of the evolution of the digestive canal, and from the analogy of malformations in other parts ; namely, the absence of one or both of the terminal orifices of the tube, to- gether with more or less of its adjacent seg- ments. Thus the imperforate anus, which is some- times limited to the mere occlusion of the lower orifice of the bowel by a thin mem- brane, is, in other instances, associated with the absence of a variable extent of the rec- tum, and even of the colon, ileum, or jeju- num. In such cases, a cord of more or less dense fibrous tissue generally replaces a vari- able extent of the absent segment of tube. The canal itself is usually dilated above its closed extremity. It may, however, com- municate with the neighbouring urinary or genital cavities ; or it may even open at the umbilicus.* The analogous deficiency of the oesopha- gus is of less frequent occurrence than the preceding, and is but very rarely associated with it. Here the pharynx ends below in a blind extremity ; generally forming a pouch, which sometimes communicates anteriorly with the adjacent trachea. The oesophagus below this pouch begins in a similar but nar- rower sac, which is separated from the pha- rynx, either by a membrane, or by a fibrous cord, or by an absolute interval of varying length. The deficiency of the stomach occurs chiefly in acephalous monsters. It is some- times accompanied by the absence of the duodenum, or part of the jejunum. * In that class of double monsters in which the trunks are distinct below, but united above in the upper part of the belly, a variable length of their two small intestines is sometimes similarly fused into a single tube, wdiich bifurcates above and below. The seat of the lorver bifurcation is some- times occupied by a (probabl}' true) diverticulum. An incomplete evolution of the remainder of the tube is evinced, either by a local nar- rowness of variable* extent and situation, or by a closure and interruption which (inutatis mutandis) repeat the various grades of this malformation seen in the occluded oesophagus and anus. Or it may exhibit a somewhat analogous tendency of the more complex parts of the canal towards the simply tubular shape. Thus the stomach may be devoid, either of its cardiac sac, or of its pUoric valve; or may present a cylindrical form, precisely like that of the small intestine. Or the valve or pouch of the projecting coecum, or its vermi- Ibrm appendix, may similarly disappear.f The maximum of this imperfection renders the whole intestine a narrow cylindrical tube, in which it is impossible to distinguish be- tween the large and small bowel. Almost all the foregoing malformations, where excessive, are accompanied by other deformities, which affect the neighbouring or- gans. Thus the deficiency of part of the rectum is a common coincident of the rao- nopodous state, in which the two lower limbs are fused into one. (2.) The excess of development to which we may refer the second class of malforma- tions of the digestive canal, consists in an increased length or width of the whole tube, or of any particular part of it. In the latter case, the large intestine, the coecum, and the stomach are the segments most frequently affected. The other local malformations which we may ascribe to such an excess, are those of subdivision of the canal on the one hand, and the production of diverticula or supplementary tubes on the other. Very few of the transverse subdivisions of the tube can, however, be regarded as really belonging to the category of excessive de- velopment. For even where these, as in the stomach, subdivide the cavity of the canal by imperfect septa, into abnormal portions, still the latter generally exhibit a diminished, rather than an increased size.J The longitudinal division of the tube pre- sents us either with a septum, which separates its interior into two channels, that communi- cate again below ; or with a double canal, of variable length and position. The double coecum which has sometimes been observed, might be regarded, either as a bifid or double state of the canal, or as the * In rare instances this narrowing is so great as to constitute a virtual occlusion. Thus cases are sometimes met with, in which the whole of the in- testinal canal below the duodenum or jejunum con- stitutes a tube, which retains the formal separation into large and small intestine, but evinces its checked development by^ its narrow calibre, and by the dilatation or pouch above it, that terminates the normal segment. t In some of these latter cases it is probable that the projecting cul-de-sac, which appears to be the coecum only, is in reality the undivided rudiment of both it and the vermiform appendix. J Some of these transverse subdivisions of the tube possibly imply a mere arrest of development in the site of the imperfect septum, without any excess of this process in the contiguous parts. D D 2 STOMACH AND INTESTINE. 40 i co-existence of a diverticulum with the nor- mal pouch of tliis part. Tlie diverticula of tlie intestinal canal seem to be of two kinds, which differ, not only in the frequency of their occin rence, but also in their situation, form, structure, and (in all probability) in their nature or import. The least common variety form pouches of variable length, width, and shape ; which may spring from almost any part of the canal, but are usually connected with the small intes- tine. Their structure vai'ies ; but, as con- trasted with the bowel itself, they usually exhibit more or less deficiency of the mus- cular coat.* The true diverticulum differs materially from these. It usually forms a short tube of in- testine, which leaves the ileum at from l.V to 2 feet above its termination ; by what is either a right angle, or is such as gives it an incli- nation towards the lower [lart of the bowel. Its width generally ap[>roaches that of the ileum, with which its cavity is continuous, by an aperture that is sometimes valvular. It jjossesses the ortlinary muscular and mu- cous coats. The former exhibits its usual transverse and longitudinal layers. The latter also presents its ortlinary structure: being occupied by villi, tubes, aiul follicles ; anti sometimes, by valvulae conniventes of remark- able tlistiuctncss for this region of the bowel. Its length is generally about three or four inches. Its shape is more or less cylindrical, oftener contracting than expanding towards its termination. It commonly sustains vessels, anti is attached by a kind of mesentery. Oc- casionally it exhibits, in adtlitiou to these vessels, a cellular cortl that evitlently contains the degenerated relics of some large artery. And finally, it sometimes extends upwai'ils towards the umbilicus ; and, in rare instances, opens here. From all these circumstances there can be little iloubt of its true import being that assigned to it by Meckel ; namely, that itis a highly developed and persistent por- tion of the duct of the umbilical vesicle. (3.) The thiixl or remaining group of mal- formations includes most of the congenital displacements of the digestive canal. These, as already mentioned, juay be ascribed to two very different causes. The transposition or displacement of the tube within the abdomen, whether total or partial, is a fact for which the history of its development affords no ex- jilanation or probable secondary cause.f While the situation of any part of the canal * Hence some anatomists regard these pouches as constituting a kind of hernia of the mucous membrane. But unless this view imply that they are, at least in part, of mechanical origin, it can only amount to a circuitous statement (and often an exaggerated one) of the above fact. It is however probable, that some of these diverticula really are the results of accident. t In rare instances, the stomach or colon take a vertical position, which, to some extent, suggest an arrest of their development. But little stress can be laid upon such a conjecture, unless it be con- firmed b}" other appearances of the same kind in these or neighbouring parts. externally to the cavity of the belly, is, in most instances, the mere result of a defi- ciency of the abdominal pariete.s. The partial displacement of the canal gene- rally affects the transverse colon, or some other segment of the large intestine ; and, more rarely, the stomach. Its total transpo- sition inverts the position of all the abdominal viscera with respect to the median line: so that, for example, the pylorus, the ccecum, and the ascending colon occupy the left side of the belly ; while the cardia, the descending colon, and its sigmoid flexure, are found on the right, or opposite side. The congenital inguinal hernias form the most familiar illustration of the second (or extra-abdominal ) class ofdisplacements. And when a similar arrest of development involves the anterior wall of the belly generally, the abnormal situation of the canal may assume any grade, from that of a limited umbilical hernia, to an external situation of almost all the intestinal canal. While the deficiency of the diaphragm may allow a valuable extent of the canal to occupy the cavity of the thorax. From obvious reasons, it is the commence- ment of the small intestine, which usually experiences this displacement. The stomach, above the hernia, is sometimes dilated. Morbid Conditions. — Size. — Alterations in the size of the alimentary canal, though they chiefly affect its calibre, ai'e generally asso- ciated with changes in its walls. Constriction. — Narrowing or diminution of calibre is sometimes general, but is more fre- (juently limited to a part of the tube. Its causes are various. 1. It often results from a process of con- traction, which specially engages the muscidar coat. Such contraction, generally passive, is well exemjrlifietl in the narrow empty tube, seen where the canal has for some time re- ceived no contents. Thus in persons who have died of starvation, the intestines are sometimes reduced to a tube, with pale thick walls, and a narrow calibre, like a tobacco- pipe. While a more local change of the same kind is often found in the empty seg- ment of the intestine immediately below an obstruction, or an artificial anus. During its rigor mortis, the dead intestine often presents similar appearances. These may, however, be distinguished by their originating in a more active contraction, by their exhibiting a more marked, but less permanent character, and by their involving a less extent of bowel. And lastly, various irritants and astringents have been found to excite the muscular coat to contractions, which can more or less imitate the diminution of calibre producible by the preceding causes. 2. Narrowing may also result from the con- traction of other intestinal tissues, besides the muscular coat. The constriction produced by the immediate or local action of the corro- sive poisons on the alimentary canal, may be partially ascribed to their direct chemical in- fluence on the various textures with which they come into contact. Such poisons, for STOMACH AND INTESTINE. 405 example, absorb the water of these tissues, coagulate their albumen, and thus corrugate and condense their mass. The narrowing which is produced by inflammation or by morbid growths, may be regarded as more mechanical. It results, either from the ex- sudation or deposit directly engaging more or less of the cavity of the tube ; or what has a similar effect, from its ultimate contraction first reducing the size of the diseased part, and then trenching upon that of the neigh- bouring healthy parietes. ^\'here the deposit of the new substance has been preceded by a loss of the normal tissue, — as often occurs in inflammation and ulceration — the con- striction which is thus subsequently brought about is of course much more considerable. 3. To the above causes of constriction in- trinsic to the tube, we may add several which are extrinsic to it. These are chiefly impor- tant, either by the inflammation they excite, or by the obstruction which constriction beyond a certain limit is apt to produce. Hence they will be hereafter alluded to, in connexion wdth those displacements of the tube, by wdiich obstruction is most frequently brought about. Dilatation. — An increase in the calibre of the digestive tube may be the -result, either of distention of its cavity, or of relaxation of its walls, or of both of these causes conjointly. Thus that segment of the canal which is im- mediately above an obstruction, is always found in a state of distention : its dilatation being obviously produced by an onward trans- mission of the intestinal contents, to the point where their progress is arrested. And even in the absence of direct morbid obstruction, constant distention of the tube can to some extent imitate this state. Thus the colon of persons habitually constipated, frequently be- comes enlarged to a vast extent. And the stomach of the rice-eating Hindoo, or the potato-eating Celt, often acquires a similar in- crease of capacity. In many of these cases it is, however, pro- bable, that the passive distention of the organ is assisted by an actual relaxation of its walls. In the enlarged bowels of obese individuals there can be little doubt that this is the case. And most of the diseases at present asso- ciated under the name of ileus exhibit, as one of their characteristic changes, a relaxa- tion of the bowel, which may be distin- guished from the preceding by its rapid occur- rence, its morbid nature, and its usually con- siderable amount. Thickness. — It is seldom, if ever, that the walls of the intestinal canal are altered in their thickness only. Aiiart from the obvious physical effects of distention and constriction, by which their tenuity is respectively increased and diminished, the coats of the bowel rarely undergo changes in this respect, without pre- senting some other appearances, such as be- tray a more important lesion. Indeed, the foregoing alterations in calibre are often as- sociated with changes of texture. Thus, in persons who have died from slow starvation, the intestines become extremely thin, soft, and transparent. A similar change sometimes accompanies that atrophy of the tube, which is produced by tubercular perito- nitis or by diarrhcea, and is attended by an anmmic pallor of the canal. The dilatation caused by obesity is usually associated with an increased thickness of the intestinal pa- rietes; a condition which has been compared to hypertrophy'. Here, however, a careful examination will easily show that the real nutrition of the tube has by no means under- gone an increase commensurate with that of its bulk. The bowel is indeed enlarged ; but its muscular coat is softer, paler, and weaker ; and its whole appearances are those of a thickening, which is chiefly due to an increased effusion of fluids interstitial to the normal solid structures. Situation. — Changes in the situation of various parts of the canal are by no means uncommon. We have already alluded to the great freedom of movement which is natural to the small intestine*; and have specified the various regions of the abdomen which distention of the stomach or large intes- tine :|l may cause these segments respectively to occupy. We have also briefly mentioned the more frequent congenital displacements. We have therefore only to enumerate those displacements which are independent of the above causes. The abnormal positions of the different parts of the intestinal canal are naturally divi- sible into the extra-ahdorninnl, and the intra- abdominal; in other words, into those in which they are placed externally to the abdo- minal cavity'; and those in which their change ra situation is within the belly, and thus al- lows them still to be bounded by its walls. The first of these classes includes the various kinds of hernia; in -nhich an unna- tural deficiency or weakness of some part of the abdominal parietes allows a portion of the canal to be protruded through them ; forming a displacement which, according to the situation of the protrusion through the wall of the belly, is called inguinal, femoral, abdominal, umbilical, or diaphragmatic hernia. Amongst the second class of displacements, or those which are included within the pa- rietes of the belly, we may first mention some, which are attended with few, if any, symp- toms during life ; and are, at least in many instances, a mere adaptation of the canal to external pressure. Thus the habit of tight-lacing sometimes gives the stomach an hour-glass shape, some- times thrusts down its projecting cardiac pouch, towards the left hypogastric region and the pelvis. In like manner, the bulk of the organ may be forced aside into various un- usual situations by the pressure of any tu- mour in its neighbourhood. Thus, during the latter stages of pregnancy, the uterus so far encroaches upon the stomach, that the latter impedes the descent of the diaphragm, and * See p. 340. f See p. 309. J See p. 3G2. et .seq. n n 3 •1-OG STOMACH AND INTESTINE. tlms claims a consiilcrable part of the trunk which generally belongs to the thorax. The duodenum is so fixed as scarcely ever to be displaced, except when it is dragged out of its normal position, by displacements of the stomach or small intestine. It is in the large intestine that such devia- tions of position are most frequently found. In the coecuni, however, they are by no means common ; or if present, are generally limited to a descent of its dependent left extremity into the pelvis. The more frequent displace- ments of the ascending and descending colon seem usually |troduccd by changes, which principally engage the segments that imme- diately succeed them. Thus the transverse colon sometimes appears to he wanting; being converted into a narrow arch, with the con- vexity upwards, and having sides which are no way distinguishable from the ascending and descending colon. The reverse of this state is even more common, in which the arch, instead of being horizontal, has its centre depressed towards the hypogastrium, so as to form an abrupt vertical bend, with the con- vexity downwards. Here the neighbouring ascending and descending segments of the bowel are, as it were, drawn into the increased length of transverse colon, so as to be them- selves greatly shortened. And finally, the displacements of the sigmoid flexure, which are even more common than the preceding, resemble them in the modifications which they impress on the normal length and curva- ture of the tube. Sometimes they merely exaggerate the natural curve of this part ; sometimes they lengthen it at the expense of the descending colon, or even of the rec- tum ; and occasionally the curve is, as it were, transferred to the latter bowek Lastly, the sigmoid flexure is sometimes preceded by a long segment of tube, which carries it over to the right iliac fossa ; where it is so fixed, that the rectum which succeeds it, shares its displacement, is attached to the right sacro- iliac symphysis, and only gains the median line towards the middle of the sacrum. The origin of many of these displacements is scarcely at present ascertained. But there is little doubt that they are often produced by tight-lacing, as above alluded to. Such a con- jecture is confirmed by the fact, that they are almost limited to the female sex. They seem to occur most frequently in persons who have borne children. We have next to notice a form of accidental displacement, in which the change of situation, though limited in amount, is much more se- rious in its results, leading to an obstruction that is usually fatal. It includes the various kinds of torsion, and the intus-susception or inversion of the canal. In the /orshm of the intestine, a portion of bowel is more or less twisted, either around its own axis, or around a centre formed by a variable extent of the neighbouring mesen- tery. The parietes of the tube are thus brought into contact with each other, with the effect of completely occluding its calibre. In what way this twisting is effected, or why it is not soon effaced by the subsequent dis- tention of the bowel, it would be incompa- tible with the limits of this sketch to inquire. In intus-siisce-ption, the obstruction is ef- fected by the passage of a longer or shorter segment of the canal, with a portion of its adjoining mesentery, into the cavity of the next or following segment. The anatom\' of this displacement may be best traced by a brief narrative of the steps of its occurrence ; at any one of which death may intervene. Mobility of the tube is an essential condi- tion of its production. Hence intus-sus- ceptions are generally found in the small intestine, and sometimes in the large intes- tine ; but rarely or never in the duodenum. Irregular contraction of the muscular coat seems equally essential to their occurrence. Hence we often find them in dead bodies, as a result of the intestinal rigor mortis. While their occurrence during life can often be traced to a casual diarrhoea, which seems to form at least their exciting cause. They are almost invariably produced by the reception of a superior into an inferior segment of bowel. It would therefore seem that they “ originate as a kind of perverted peristalsis: — that, the longitudinal fibres re- maining quiescent, the intestine is surprized by a transverse constriction, the rapid advance of which hurries the contracting portion into the flaccid and dilated part immediately anterior to itself”* The whole of this process appears to be well illustrated by the ordinary action of the oesophagus, the lower end of which tube undergoes a temporary intus-susception into the stomach at the end of every act of deglutition.j- The way in which the transverse contrac- tion of a segment of intestine furthers intus- susception, receives some illustration by its frequent occurrence in cases where a poly- piform tumour is attached by a pedicle or stalk to the interior of the intestine. Here the traction exercised by the stalk of the tumour on the wall of the bowel from which it takes its origin, appears to assist the muscular contraction of the segment which immediately propels the tumour itself, in producing the intus-susception. The mechanical obstruction produced by an intus-susception is probably always an indirect result. It is perhaps aided by the obliquity of the received portion, the open end of which is always inclined towards the me- senteric border of the bowel. This obliquity seems due, partly to the pledget of mesentery, which shares the occupation of the outer or receiving segment of intestine ; partly to the greater distention undergone by the free mar- gin of the bowel above. In large intus-sus- ceptions, the mesentery thus forms a thick strong cord, that not only ties down the bowel by its inner margin, but constitutes the * Author, Op. cit, p. 17. . , STOMACH AND INTESTINE. 407 axis of the spiral and dilated segment of tube around it. The congestion and strangulation of the vessels of the peritoneal fold, as well as of those of the invaginated bowel itself, soon cause a swelling, that fixes the innermost segment firmly in its abnormal position. An exsudation of serum and 1\ mph next increases its size, at the same time that it renders these changes of situation permanent. The dila- tation of the preceding part of the canal, by the fluids passed into it from above, often further exaggerates the above changes. The sloughing which from all these causes finally ensues, sometimes has the effect of setting free the intns-suscepted segment in the cavity of the canal. Hence, if the patient survive until this separation occurs, the dis« charge of this segment from the bowels may terminate all the symptoms of obstruction ; and leave the bowel at the site of the intus- susception occupied by a ring of lymph, which gradually contracts into a firm cicatrix of fibrous tissue. From the preceding changes in the size, shape, and situation of the digestive canal, we pass on to consider the abnormal conditions of its texture. Softenbig is the first of these conditions which claims our notice. In rare instances, this change engages the whole of the digestive canal, to which it im- parts a semi-transparent gelatinous appear- ance, and a pulpy diffluent consistence. In this general softening, the walls of the canal are usually diminished, scarcely ever in- creased in thickness. Their colour is gene- rally pale enough to warrant us in regarding them as in a state of anaemia. But they sometimes exhibit those various shades of discoloration which are present in the more localized forms of softening. The latter are usually found in the sto- mach, where they especially occupy the car- diac pouch. But they are sometimes seen in the large intestine : — indeed, in most sub- jects, the mucous membrane of this part of the canal has a somewhat softer consistence than that of the small intestine. It is in the stomach, in which the process of softening occurs with most frequency and intensity, that we may best notice the details of this change, and the degrees in which it generally engages the different tissues of the coats of the canal. Of these the mucous membrane is that which always seems to suffer first and most ; in which the process appears to commence, and to which it is often limited. At first, the only noticeable change is a diminution of its consistence : a change which either occupies isolated patches of its surface*, or is spread over a considerable extent of the cardiac sac, rendering it liable to break down on the application of the slightest pressure. Hence if a portion be taken between the blades of the forceps, it will come away between them on exercising a very moderate traction. The mucous mem- * These are sometimes the projecting summits of the ridges formed by its mucous folds. brane next becomes absolutely broken down ; so as to form a granular pulp. This pulp covers the subjacent tissues with a layer of variable depth ; the deficiency of which, here and there, lays bare the submucous areolar tissue. The process may next engage this and the muscular textures ; either imparting to the latter a paler, softer, and thinner ap- pearance than natural ; or implicating the whole thickness of the gastric parietes, and giving them a gelatinous appearance. A con- siderable thinning of these parietes almost always accompanies this change, and is some- times so great as to cause the rupture of the organ, and the effusion of its contents. Fi- nally, in extreme cases, the contiguous tissues of the belly, and especially the muscular sub- stance of the diajihragm, become involved in an extension of this process from the sto- mach. The colour associated with this loss of consistence is very variable. In some cases, there is a complete anmmia of the gastric coats ; in others, this term is rendered some- what less ap[)licable by the [iresence of one or two large veins distended with blood. In other instances, w'e find the softened part of the stomach coloured a variable shade of brown, red, or even black ; according to the quantity of blood it presents, and the degree in which its hue has been altered by the gas- tric juice. Finally, in many cases the organ offers no appreciable contrast in this respect with its normal state. It is j)robable that these softened states of the digestive canal are capable of being produced by very different causes. Even after setting aside all those instances in which the softening has been preceded by symptoms of inflammatory action during life; and all those in which it has been due to the inges- tion of poisons which exert a direct chemical action of this kind ; we may trace the process to three causes, which often coincide in its production, and the exact share of which it is therefore often difficult to estimate in any particular specimen. These causes are, pu- trefaction, digestion, and altered nutrition. The amount of influence which has been exerted by putrefaction, might seem very easy to determine. But we cannot always esti- mate it by the date which has elapsed since death, or the temperature to which the body has been exposed ; since its access and rapi- dity vary remarkably according to the state of the organism, and the nature of the fatal dis- ease. The capacity possessed by the secretion of the stomach for digesting its coats after death is one which will obviously depend on the nature and amount of this fluid present : and will, other things being equal, attain its maximum in the case of the sudden death of a healthy person, soon after the ingestion of food. The softened state of intestines, which is often found in diarrhoea, lever, and other disorders, — as well as the peculiar softening* * The characters of this softening appear to in- D I) 4 408 STOMACH AND INTESTINE. of the stomach, long known to occur in ill- nourished infants, or in cases of hydrocephalus or brain disease, — point just as decidedly to the inlluence of an abnormal state of nutri- tion in favouring this state. Lastly, there are many cases of acute dis- ease, in which the softened stomach is more or less coloured by blood that has stagnated in its walls, where we have the additional dif- ficulty of determining whether this congested condition preceded or followed death. Ilypcnxmia. — The hyperaemia of the diges- tive canal constitutes an abnormal state, the correct appreciation of which is of gi'eat pa- thological importance. Of course, even the loosest interpretation of the term w'oidd limit it to an increase in the (jnantity of blood pre- sent in the vessels of the alimentary tube ; and would thus e.xclude a condition which is ca- pable of being confounded with it : namely, a transudation of the mere colouring matter of the blood from neighbouring parts. But there are many circumstances which render it very difficult exactly to determine the amount of true hyperaemia [iresent in any segment of the digestive canal after death. Thus, while there is little doubt that hyper- aemia is a stage of almost all the processes ordinarily regarded as inflammatory, as well as of those which result in the deposit of adventitious growths, the examination of the digestive canal after death shows that this condition by no means accurately coincides with these processes. On the contrary, it is often absent in the very cases in which the symptoms during life might best entitle us to expect it. Ami conversely, it is often [iresent where death has been the result of accident, or of disease no way referable to the organ which is the seat of the congestion. We are therefore bound to conclude: (l.)that the presence of hyperaemia in any part of the di- gestive canal does not necessarily prove this part to have been the seat of disease during life ; and, (2.) that the absence of hyperamia in the dead structure does not disprove its previous presence in the living organ. And we have therefore to inquire: — (I.) What causes can [iroduce it in the healthy tube? (2.) What circumstances can efface it from the diseased tube? And (3.), what are the marks by which we may recognize hyperaemia in the corpse, as a true and cliaracteristic relic of diseased action during life ? It is to the [ihenomcna of death, as this process usually affects the organs of circu- lation, that we must first look for an answer to the above questions. A very cursory allusion to these phenomena may suffice to indicate, in what manner they can by turns imitate, moilify, or efface the state of true hyperieqiia occurring during life. The rigor mortis of the dying arteries flushes and dis- tends the capillaries beyond them with an ab- normal quantity of blood. The degree, date dicate that although it is probably preceded and assisted by an iniliealthy state of the tissues of the stomacli, the gastric juice is at least the chief im- mediate agent of the change. and extent of this arterial contraction in dif- ferent vessels, will obviously be capable of imparting almost any moderate amount of distention or congestion to the terminal net- works they respectively supply. And at a later period after death, the gravitation of the now stagnant blood may distend the vessels of any dependent part of the body. But the congestion of one part implies — other things being equal — the drain of some others which are immeiliately contiguous to it. And hence the very occurrences which can cause mode- rate hyperaemia in a healthy segment of in- testine, may at the same time produce a cer- tain amount of anmmia in another ; and may therefore diminish — and, when moderate, re- move— a state of simple congestion due to disease. It would be easy to accumulate instances of the fact last alluded to. The state of really intense, though healthy, hypermmia, which is present during the [)eriodic activity of the stomach or other parts of the canal, rarely leaves any traces after death, unless in animals who are examined very speedily after this event, and before these new adjustments of its circulating fluids have had time to take place. In like manner, the increased vascu- larity of the intestines which accompanies cholera or diarrhoea is often just as com- pletely effaced after death: — disappears, in short, in the same manner in which the red- ness of erysipelas and various other eutaneous disorders rapidly fades away in the first few moments that immediately follow the last breath. But, even with all allowanees for sneh sources of error, the condition of liypertEmia is one of the highest significance in the patho- logy of the digestive canal. It is, generally, an important sign of disease. And, with proper attention to its collateral circumstances, its import need rarely be misinterpreted. Thus, as regards the extent of the process, an intense and minute congestion is almost always morbid ; and is obviously much less likely to be removed by the phenomena of death, than one of more moderate hyperaemia. Again, a long duration of the abnormal vascu- larity, as in the hyperaemia of chronic disease, generally brings about such a definite and per- manent enlargement of the vessels concerned, as evidently tends to enable them better to resist the action of these cadaveric changes. In other instances, a similar result appears to be produced by a process of exsudation around the vessels; and by changes in the structure of these tubes themselves. It must, however, be confessed, that we do sometimes meet with sjjecimens of tolerably intense con- gestion of a part of the alimentary canal, where it is only from the presence or absence of corresponding symptoms during life, that we can conjecture whether the state of hyper- ^ eemia has preceiled or followed death. Of course, the mere hyperaemia of any net- work of capillaries may be determined in tw'O* ways : — either by an increased afflux, or by a diminished reflux, of the blood. But the 409 STOMACH AND INTESTINE. first or “ active ” form of congestion may ge- nerally be distinguished from the latter or “ passive ” variety. The active hypercemia is immediately attended by an enlargement in the calibre of the afferent arteries; the pas- sive, by a diminution in that of the efferent veins. Again, the former usually has the colour of a tolerably scarlet or arterial blood ; the latter, that of a darker and more venous fluid. Lastly, the active form affects chiefly the minute arterial branches and the capil- laries ; the passive is most prominent in the veins which come from these ultimate vessels. The hyperaemia of enteritis and of cirrhosis respectively, might well illustrate this con- trast. Amongst the varieties of hyperaemia, we may notice a more or less complete limitation of this state to the capillaries of particular tissues. Thus the microscope sometimes reveals a congestion of the gastric or intestinal mucous membrane, that specially engages those capillaries which surround the mouths of its tubes. In other instances, their blind extremities exhibit a similar state of injection. The exact cause of such partial hyperaemia is scarcely known. But the first of these va- rieties appears to be generally connected with a very limited amount of congestion. In accordance with this fact, it seems frequently to occur during or after death. Hesmorrhage. — Haemorrhage is by no means an unusual morbid occurrence in the digestive canal. Of course, the mere presence of blood in some part of the alimentary tube, affords no proof that it has been derived from the vessels which occupy its walls. The blood which reaches the pharynx in cases of hcemoptj'sis, or of lesions of the nose, mouth, or pharynx, is often swallowed, and is thus introduced into the stomach or bowels. In like manner, blood effused into the ducts of the liver or pancreas, may be carried onwards through these tubes, so as to simulate liEemorrhage into the intestinal canal ; or the blood ex- travasated into cysts, abscesses, and tumours, may find its way, through some abnormal opening, into the cavity of the bowels. It was formerly supposed that, in many cases of haemorrhage, the walls of the vessels remained uninjured ; or, at least, unaffected by any definite solution of continuity: the blood being set free from its channels by “ exhalation ” through their porous walls. But we now know that this doctrine is in- correct ; that the walls of even the finest capillaries have no pores of appreciable mag- nitude, such as are necessary for the transit of blood -corpuscles ; and hence that the “ extravasation ” of these structures is, ipso facto, a proof that some blood-vessel has been ruptured. That, amongst the myriads of these minute tubes ])resent, we often fail to detect the exact seat of the lesion, need, of course, little surprise us. The frequency with which haemorrhage oc- curs in the diges'.ivecanal, seems related chiefly to the number and delicacy of its vessels, to the nature of its tissues, and to the mode in which these structures are arranged with respect to each other. Amongst such pre- disposing causes we may especially notice, that the greater part of its large vascular supply breaks up into a vast and dense network of capillaries, which is placed in the closest proximity to the free surface of the mucous membrane. While the latter structure not only has a consistence which disease can readily reduce below what is necessary for the mechanical support of these delicate ves- sels ; but is the constant seat of muscular movements, which agitate it in almost every conceivable plane. The extravasated blood may either occupy the interstices of the intestinal tissues, or may make its way into the cavity of the canal. The former case is much the less frequent of the two. As sve might infer from the ana- tomy of the tube, the areolar tissue around the submucous stratum of vessels is by far the most frequent situation of such intersti- tial hsemorrhage. The blood which is effused by htemorrhage into the cavity of the tube itself may be either fluid or coagulated, arterial or venous, pure or mixed, changed or unchanged. With respect to the latter alternative, we may ]ioiut out, that blood effused into the digestive canal not only becomes mingled with the various ingesta and secretions which may chance to be present, but gradually undergoes a kind of digestive process, that often has the effect of greatly modifying its colour and consistence. Hence, where the extravasated blood has been sufficiently exposed to this action, it will gene- rally be found to have acquired adark,grumous, or even black colour, and a peculiar tarry or almost piiltaceous consistence. While con- versely, if the effusion be excessive in quan- tity, or recent in occurrence, it may be pure enough to testify to its arterial or venous source. A small quantity of blood thus altered by digestion sometimes simulates the colour and appearance of inspissated bile. But by diluting the sanguineous mass with water, its dark-purple or blackish hue may be at once distinguished from the rich yellow colour which is proper to the biliary secretion. And a microscopic examination would, of course, assist (oreven replace) this means of diagnosis. The nature of these intestinal haemorrhages is very various. Apart from mechanical injuries of the canal by foreign bodies ap- plied to it from within or from without, we may classify (but scarcely separate) them into haemorrhages from two sources: — from abnormal states of the vessels themselves ; and from diseased conditions of the con- tiguous tissues. As examples of the former variety, we may adduce the haemorrhage produced by the rup- ture of an atheromatous artery; or the ex- travasation which occurs in cirrhosis from obstruction and distention of the portal veins. The htemorrhage of inflammation, of ulcer- ation, of atony, may be referred to the second 410 STOMACH AND INTESTINE. variety. Bat even here, just as it is evident that lesions of the vessel themselves always constitute the immediate cause of the ex- travasation, so we can liardly doubt that such lesions may (and often do) form a predomi- nant, thougli not an exclusive, element in the process. Infammation. — Inflammation constitutes the most frequent and important of all the morbid conditions of the alimentary canal. Indeed, there are very few of these condi- tions with which it is not more or less directly concerned. It is generally, if not al- ways, preceded by hypermmia ; often by down- right haemorrhage ; and itself usually precedes the occurrence of ulceration and gangrene. It is the necessary residt of mechanical in- jury to the various tissues of the tube ; and is often an immediate consequence of the dis- eases or injuries of neighbouring organs. There is little doubt that it is often concerned in the production of those conditions which we at present include under the name of hypertrophy. And it is also capable of being evoked by the presence of adventitious growths, even though their origin may be regarded as independent of its presence. Finally, it constitutes one of the most charac- teristic phenomena by which various diseased states of the blood declare their influence on the system. Such a diversity in the forms of the inflam- matory process, as it affects the intestinal tube, might well lead us to expect variations at least as considerable and numerous in its nature. These, however, the space allotted to the present article will not allow us even to sketch. As little can we enter upon the dif- ficult subject of its true pathological relations to the other morbid processes just alluded to. We must be content to accept the term in- flammation as it is ordinarily made use of; and to enumerate its aj^pearances, as they are usually seen in the dead body. The mere existence of congestion we have already found to be no certain indication of the inflammatory state ; but, on the contrary, one which would often deceive us, if viewed in this light. And though the presence of an exsudation forms a test which is far less frequently fallacious, yet even it requires some qualification, before it can be accepted as tantamount to proof of inflammation. For just as, to speak physiologically, it is the very office of the blood-vessels to mediate and permit an exsudative process of definite na- ture and amount, so slight differences of the exsuded fluid in both these respects, from that normally poured out, are not even in- compatible with health, much less character- istic of inflammation. Hence, in saying that “exsudation” is a main feature of inflamma- tion, we are using the word, not so much to express an isolated fact, as to imply a com- parison : — an exsudation, of such a quality, and in such a quantity, as to offer a marked contrast with the specific fluid which is poured out by a secreting organ, on the one hand ; or with the healthy nutritional fluid which bathes the interstices of its tis- sues, on the other. Of the two contrasts thus implied, that of quality is obviously much the more important. Thus, while the copious interstitial juices of the swollen but flaccid intestine of a very corpulent person, offer little difference from those of the typical healthy adult, save in their (so to speak) more diluted state, — or while the intestine of a dropsical abdomen is chiefly enlarged by an increase of the ordinary fluid of its submucous tissue, — the vessels of the inflamed alimentary tube take on what is more or less a new, as well as an increased action ; by virtue of which they pour out, into the tissues or the cavity of the canal, fluids which a^e very different to those nor- mally present in this situation. Using the term “ exsudation ” in this restricted sense, we should scarcely do wrong in regarding it as the chief feature of the inflammatory pro- cess ; and as an appearance which, when seen accompanied by the ordinary marks of hy- permmia, quite entitles us to affirm that the part in which it is situated, was the seat of inflammation during life. And not only does the presence of exsuda- tion form the characteristic mark of inflam- mation, but the basis of the classification under which we may best arrange the varie- ties of this process. Thus according as the characters of mucus, pus, or amorphous protein, predominate in the exsudation poured out, we distinguish the process which has given rise to it as catarrhal, jmriform, or croupy inflammation. The ra- pidity of its effusion is at least a frequent and important element of these peculiarities which are summed up in the epithets ‘’■acute" and “ chronic" And finally, as regards its extent and situation, it not only ranges from an in- flammation of the mucous surface only, to one which successively involves the subjacent muscular and peritoneal coats, but may even specially affect the submucous areolar tissue of the canal, or engage certain parts of its secretory apparatus in the shape of its tubes or follicles. Each of these modifications will be noticed in a few words. The catarrhal inflammation of the mucous membrane offers precisely the appearances seen in catarrh of other mucous surfaces. The numerous vessels of the membrane exhi- bit a state of more or less intense hyperaeinia, giving it a corresponding shade of that red colour which is generally producible by vas- cular injection. This increase of vascularity is stated by Rokitansky to be chiefly visi- ble, sometimes in the villi, sometimes around the follicles. But it seems to me that its being limited to the latter is often due to the contraction of the villi * having thrown back the blood they contain, into the adjoining fol- licular network with which they anastomose. The exsudation thrown out in this form of inflammation, may be traced in two situations; — in the textures of the canal itself, and in * Comp.ire p. 54. STOMACH AND INTESTINE. 411 its contents. In the former, it gives a soft- ened, swollen, relaxed, and watery appearance to all the coats of the tube, and especially to its epithelium and submucous areolar tissue. In the latter, we notice certain changes in the fluids poured out upon the inner surface of the tube. The contrast between these fluids and those whicli are present in health is probably closely analogous to that which obtains in other catarrhs. The specific normal secretion is arrested, and is replaced by a variable (usually a large) quantity of a thin watery fluid. The effusion of this fluid coincides with the detachment of the proper epithelium of the mucous coat from the subjacent base- ment membrane ; a process that is generally followed by the shedding of large numbers of imperfect or abortive cells, which take their origin in the same situation. The admixture of this cell-growth imparts to the catarrhal exsudation its w'ell-known gelatinous or mucous characters, and viscid consistence ; properties which the microscope shows are partially due to the solution and rupture of these delicate cells, causing the escape of their contents into the surrounding fluid. The latter is either transparent, or of a cloudy, whitish, reddish, or grayish colour. The last of these appearances, when not due to an admixture of foreign ingredients, is mainly derived from the quantity of these cells, many of which generally assume more or less of the characters of pus. The reddish hue is due to an admixture of blood, by that process of haemorrhage which so frequently results from congestion in the delicate mucous mem- branes. The 2»triform variety of inflammation might, at first sight, seem scarcely worthy of dis- tinction from the catarrhal. For the two merge into each other by innumerable grada- tions in the character of their exsudation. And the general tendency of catarrh of the mucous surfaces, to end in the production of pus, is too well known to require any com- ment. But while there always seems sufficient reason for distinguishing it as a separate stage of the inflammatory process in the digestive canal, there are circumstances which render it not improbable that the mucous and puri- form inflammations of the intestinal canal are often distinct, both in their origin and nature. Thus there are some catarrhal affections of the bowels, in which lapse of time seems to have no effect whatever in exchanging mucus for pus ; while there are others in which this mor- bid product appears to be formed very speedily, or even at once. And that there are many cases which we should find it difficult to assign to one or other of these divisions, is an objection which would equally apply, not only to all the other varieties just alluded to, but to almost all the classifications we are com- pelled to use in describing the various results of disease on the healthy organism. The presence of pus in any considerable quantity', is of course easily recognized by the glairy consistence and yellow colour it imparts to the exsuded fluid, as well as by its microscopical charactere. It is usually ac- companied by a swollen and sodden state of the various textures, such as greatly exceeds that noticed in the catarrhal inflammation. The redness and vascularity of these tissues is sometimes also increased in intensity. Often, however, the bowel acquires a grayish or ashy gray hue ; or a dark reddish brown, or even slate-colour. The latter appearances are chiefly characteristic (as Rokitansky points out) of the duration of the disorder. It may be conjectured that these varieties of colour depend upon phenomena of at least three kinds. The paler tint, where not due to an interstitial deposit of pus, seems dependent on an abnormal influence which the disease exercises upon the circulation of the part, obstructing in some w'ay the flow of blood in its vessels ; an obstruction which the micro- scope permits one to suspect is rarely due to the mere physical effects of the surrounding exsudation. The various shades of red and brown appear to be determined by the changes undergone by blood, which has either stagnated within the vessels or — what is much more frequent — been extravasated from them. And the darker bluish or blackish tints are evidently caused by a variable quantity of black pigment, which probably forms the last relics of a similar degeneration of the blood, in the shape of masses of accrete (and now insoluble) colouring matter. With ordi- nary care, an admixture of biliary colouring matter can rarely be mistaken for these ab- normal products. The production of pus may, however, take place in a less diffuse form, and by a much more rapid process, than that which causes the discharge of puriform mucus from an inflamed intes- tinal surf.rce. These acute local suppura- tions, as we may call them, often at once strip off the whole of the cell-growth that normally covers the basement membrane of the mucous coat ; and then immediately proceed to erode and ulcerate the subjacent textures. These ul- cerations seem peculiarly liable to form sinuses, by extending in various directions through the loose and yielding submucous areolar tissue. In rare instances, scattered abscesses are found in this situation ; — abscesses which are occasionally so isolated from each other, as to appear due to a process of purulent infec- tion bj' means of the vessels themselves, and not to any mere extension of a continuous suppurating cavity. Finally, in extreme cases, the whole of the tunics become so in- filtrated with pus throughout, as to form a soft or pulpy yellowish-gray mass ; which breaks or tears up on applying the slightest violence ; and, if life be sufficiently prolonged, becomes converted into a rotten membranous slough. The croupy or dij)htheritic variety of inflam- mation is distinguished, as its name implies, chiefly by the greater consistence of its exsu- dation ; which, in well marked cases, forms a more or less solid, opaque, white, or yellow mass, and is generally moulded to the shape of the inflamed surface, as a false membrane 412 STOMACH AND INTESTINE. of variahle thickness. It is almost always the result of a rapid or acute inflammatory process. Hence it is for the most part found connected with an intense redness and vas- cularity of the whole depth of tlie mucous membrane. And this appearance, which often extends to all the other tunics of the bowel, in some instances rapidly merges into a sloughy or even gangrenous state. The exsudation of this croupy lymph occurs in a variety of morbid conditions. As an idiopathic disease of the canal, its efhision is very rare. In some of the exanthemata, and especially in scarlet fever, it is occasion- ally poured out over a very large extent of the inflamed mucous surface of the alimentary tube. In the tuberculous cachexia it is also now and then effused. In the inflammation pro- duced by mechanical injuries, we may gene- rally observe it; mingled, of course, with blood, where there has been any lesion of the blood- vessels. Finally, in cases of poisoning by irri- tant substances, its presence is by no means uncommon. Here, however, it is important to distinguish it from the false membrane which is oiten produced by the chemical effect of the poison on the membrane itself, and on the exsudation it subsequently pours out. The mor[)hology of the proteinous mass poured out under these very different morbid states, seems to be even more variable than its physical and chemical properties. The observations which the author has hitherto been able to make, woidd lead him to infer the following conclusions : — (1.) The croupy ex- sudation of the intestinal mucous membrane generally contains a considerable proportion of a cell-growth; which is an abortive epithelium, homologous with that of the healthy struc- ture. (2.) The amount of this constituent attains its maximum in the tough white lymph thrown out during the acute inflammation of a previously healthy organism ; for example, in the lymph of the inflammation that follows mechanical injuries of the bowel, or in the croupy casts of the intestine, sometimes voideil in the earlier stages of scarlet fever or cholera. (3.) The form of this constituent is never that of the columnar cell proper to the healthy membrane ; but, even when best developed, rarely' exhibits more than its cytoblast, devoid of an outer cell-vvall. (4.) The degeneration of these cytoblasts, as marked by the disap- pearance of their distinct nucleus, and the appearance of more retractile and granular contents, mark their transition to the charac- ters of true pus-corpuscles; which thus be- come admixed with the croupy substance, and communicate to it the softer consistence and yellower colour of pus. (5.) The minimum of this modified cell-growth is found in the chronic forms of inflammations of the mucous membrane, and in the cachetic states of the system; — for example, in the exsudation as- sociated with the tuberculous state, (6.) The bulk of such deposits is a mass, which generally has a yellowish colour, and is rarely mixed with small masses of black pigment. This mass possesses a soft friable consistence. and presents an amorphous granular appear- ance under the microscope. In exceptional cases, it varies from this description : — in the firmer deposits, by offering an indistinctly fi- brillated texture ; in the softer, by exhibiting numerous highly refractile (and probably fatty) molecules of variable size. (7.) The applica- tion of re-agents under the microscope, seems to indicate a corresponding variety of compo- sition in these various forms of the croupy exsudation. At any rate, this very imperfect mode of examination permits us to conjecture tliat these exsudations consist in great part of protein-compounds, which possess very dif- ferent degrees of solubility in different cases, and are capable of undergoing a partial de- generation into a fatty material. The acute and chronic varieties of inflam- mation, like the preceding, merge into each other by infinite shades of resemblance. But they are contrasted by a number of cir- cumstances, all of which seem more or less dependent on the rate and duration of the process. Thus the acute inflammation presents a maximum both of hyperagmia and effusion ; the latter having usually either a croupy ap- pearance, or a more or less purulent compo- sition. It involves a greater depth of the mucous membrane ; and often spreads to the subjacent muscnlar and peritoneal coats, so as to cover various portions of the latter with lymph. In its most intense form, it may even convert the whole of the intestinal parietes into a comparatively uniform mass, of a dirty- red colour, and a rotten (or almost friable) consistence. The chronic variety of inflammation chiefly testifies to its duration by the presence of some one or other of the following pecu- liarities : — Its colour varies from pale red to dark brown or blackish red ; variations which are due to the exsudation being mixed with more or less of blood or pigment, as be- fore alluded to. Its consistence is less re- gularly affected, but is often increased by a kind of hypertrophy. The exsudation is, on the whole, in smaller quantity; and of a less croupy or albuminous quality. And finally, it is ex- ceedingly prone to pass into ulceration. Concerning the inflammations of the various microscopic constituents of the mucous mem- brane, it must be confessed that our knowledge is at present very limited. In most instances, the villi and tubes appear to share pretty equally in the disease. Of the two involutions of the mucous surface, how- ever, the villi seem the most liable to suffer; a fact for which it would be easy, though scarcely justifiable, to assign a mechanical ex- planation. In some instances, the blind ex- tremities of the gastric or intestinal tubes appear to suffer disproportionately, as com- pared with their upper extremities, and with ; the general surface of the canal. In such ca.ses we may often see the capillaries around these blind extremities deeply injected, or their ; blood extravasateil into the cavity of the tube; and in other instances, their natural cell con- STOMACH AND INTESTINE. 413 tents may be seen exchanged for a dark soft- ened granular mass. Precisely similar changes are often seen in the matrix of the tubes and of the villi ; in which latter situation they are generally accompanied by a loss of the in- vesting epithelium. The closed follicles of the alimentary canal are the seat of various changes : some of which are obviously connected with an in- flammatory state; while others probably have an equally definite, though less direct, relation to it. An unusual number of these follicles seems to be one of their most frequent abnormal conditions. In such cases we may often find them strewn thickly through the submucous areolar tissue of the stomach, the small in- testine, the large intestine, or even the entire alimentary canal. But not only may it be doubted w'hether this increase in their number is due to an in- flammatory process, but even whether it is a real occurrence. For in many instances there can be little question, that these follicles are not so much really multiplied in number, as re- vealed in increased nuntbers by their universal and extreme distention. We have seen* that their apparent number varies greatly in different individuals ; that, in children, they are generally very numerous and distinct ; and that even that healthy afflux of blood,which obtainsduringthe act of digestion, renders them unusually prominent and visible. Hence it is to the presence or absence of other circumstances indicative of disease, that we must look for evidence as to the really morbid character of an increase in the num- ber or size of these follicles. Wherever we find these alterations associated with a gene- ral dyscrasia, or with marks of congestion, he- morrhage, or inflammation in the surrounding tissues, or with a change in the character of the contents of the follicle itself, there we are entitled to regard them as indicative of a morbid process. And conversely, where none of these appearances are present, we must be content to suspend our judgment on this point. In typhoid fever, these follicles become the seat of a definite morbid process ; which not only constitutes a sjtecific element of the disease, but furnishes the pathognomonic lesion, which seems to dictate many of the de- tails that distinguish the t3’phoid from the other varieties of fever. The typhoid process in the intestine is almost limited to these follicles, of which it engages both the agminate and solitary va- rieties. Amongst the agminate follicles, those are most affected which lie nearest to the ilio- ccecal valve. The same rule applies to the solitary follicles, both in the small and the large intestine. In the latter segment of the canal, the change rarely extends beyond the follicles of the coecum and ascending colon. The process appears to commence by a stage of congestion or hypersmia. This is at first general, and engages the whole mucous mem- brane of the lower part of the ileum. It sub- sequently increases in intensity, and at the same time becomes limited to the neighbour- hood of the affected follicles ; so that these are surrounded with minute rings of injected vessels, which are visible from the mucous sur- face, or can be seen gleaming through the transparent peritoneum as dark vascular points or streaks. The microscope traces this conges- tion into the small vessels (and especially the veins) which intervene between the several follicles. The latter phase of congestion marks the access of the next stage : which corresponds to the exsudation and deposit of a new sub- stance within the follicles, and (to a lesser extent) in the submucous tissue of their im- mediate neighbourhood. The infiltration dis- tends the several follicles with a mass, which gives them a grayish, gra3ish red, or bluish- red colour ; and a more or less firm or pulpy consistence. They thus acquire a thickness ( 1 — 2 lines) that raises them considerably higher than the adjacent surface, and causes them to stretch the mucous membrane above. Below, they rest on the muscular tunic. Of course the shape, extent, and situation of the follicles thus brought into view, is that of the original structures. Thus, in the case of the agminate follicles, we see an oval or elliptical patch that runs lengthwise along the free margin of the bowel. While in the solitary' follicles, we find small round granules, of about the size of a millet seed, or a very small pea, irregularly scattered over the intestine. The mass itself exhibits under the mi- croscope, the ordinary constituents of the normal pulp of the follicle: mingled, however, with a variable quantity of blood ; and with an amorphous granular substance in larger quantity, and of a browner hue, than natural. The softening and breaking up of this pulpy mass constitutes the next stage of the change. In general, it occurs simultaneously over the whole of the agminate follicle : and thus de- taches from the subjacent muscular tunic, not only the new deposit, but the follicles them- selves; together with the areolar tissue by which they are connected to each other, and the tubes and villi of the mucous membrane by which they are covered. In other instances, the several follicles are softened and detached separately, or in clusters of two or three only; so as to leave some of the tubes and villi which normally occupy their intervals. In some cases, a portion of the patch undergoes a modified process ; in which the contents of the follicle seem to make their exit through small openings at their projecting summit, with little or no disturbance of the adjacent tissues. Finally, in certain instances, more or fewer of the follicles are said to undergo a retro- grade change, in which their contents undergo absorption, without either sloughing or de- hiscence. The removal of the new deposit leaves the characteristic typhoid ulcer ; the shape, size, and situation of which are therefore precisely See p. 3G0. STOMACH AND INTESTINE. 41'I indicated by the preceding description. The floor of the ulcer is formed by the rhuscular coat of the bowel, covered by a very thin stratum of areolar tissue. Its margin, some- what irregular in outline, is a reddish or bluish- gray edge of mucous membrane : which was formerly raised and almost detached from the subjacent tissue by the distended and pro- jecting follicles in its neighbourhood ; but has now fallen down upon it, so as to form a per- fectly flat, loose, and relaxed border, around the shallow ulcerated fossa of the patch. In its further progress, the ulceration may extend in two directions. In the horizontal plane, it generally follows the sha[)e, and rarely much exceeds the size, of the original patch. In the vertical plane, it may gradually destroy the muscular and [leritoneal coats, and thus give rise to perforation. Such a deepening of the ulcer is accompanied by a narrowing of its width, so that the aperture in the serous membrane is generally of very small size. Tlie cicatrization of the ulcer, which follows the cessation of the local and general malady, takes place by the devt'lopmeni of a firm, but very delicate layer of fibrous tissue, on the floor of the ulcer. This merges, by a gradual increase of its thickness, into the thickened margin be- fore alluded to, where the original mucous membrane becomes intimately blended with the new fibrous cicatrix. The latter exhibits under the microscope the ordinary characters of this variety of fibrous tissue, and is generally covered by one or two layers of irregular flattened cells. The junction of the old and new structures is often marked by wrinkles and puckers, which ajipear to radiate from the new tissue of the cicatrix ; and thus, as it were, measure and express its conti'action. In very rare instances, this contraction gives rise to an obstruction of the canal. That it does not oftener do so seems due, not only to the limited extent of the ulcer around the bowel — an extent which scarcely ever exceeds id or j:th of its circumference — but also to the little injury generally inflicted on the tex- tures subjacent to the ulcer, and to the amount and situation of the new tissue of the cicatrix. So little of this is deposited, and so exclu- sively is it limited to the surface of the ulcer, that the process of repair might almost be regarded as resulting in a mere conden- sation of those superficial layers of the original areolar tissue which are left intact by the ulcer. The above series of morbid changes in the solitary and agminate follicles, is accompanied by a somewhat similar alteration in the lym- phatic or mesenteric glands connected with the affected segments of intestine. This process closely resembles the preceding, except in the fact that it scarcely ever ends in the ulce- ration of the structures it engages. A stage of hy])ersemia is soon followed by one of enlarge- ment; the latter being tlue to the deposit of a substance, which gives to the glands affected, much the same grayish or reddish colour, and soft firm consistence, as that seen in the folli- cles. This deposit next undergoes a limited degree of softening : which is sometimes ac- companied by hrernorrhage, rarely by sup- puration, ulceration, or peritonitis ; and is followed by its gradual absorption. Tile latter process slowly restores the glands to their normal size and colour. Among the various inflammations of the different segments of the alimentary canal, there are only two to which we need accord any notice, apart from the general description as given above. These are, the gastritis pro- duced by tlie ingestion of irritant (or rather caustic) mineral poisons ; and the dysenteric inflammation which affects the large intestine. In the acute gastritis caused by caustic substances, the stomach presents appearances of two kinds: — one, which forms a series of effects produced by the mere chemical action of the (loison on the tissue, and which might therefore be to some extent imitated by in- troducing it into the stomach of a newly killed animal; and another, which represents the subsequent vital reaction of the tissue against the poison, constituting the phenomena of in- flammation, properly so called. The first of these will of course vary, not only with the nature of the poison, but also with a variety of other circumstances ; es- pecially with its quantity, concentration, and solubility, as well as with the amount and duration of its contact with the stomach. Thus according to the nature of the poison, the organ may either undergo softening and solution, or hardening and coagulation ; may either be blanched, or carbonized; coloured, or deprived of its colour; swollen by an im- bibition of fluid, or contracted by the loss of its own water of composition. The second or inflammatory class of ap- pearances will necessarily depend upon the ex- tent in which the first preceded them ; since it is chiefly in the tissue beneath the de- stroyed part, that the reactive inflammation is set up. Thus if the epithelium be the only structure which has been acted upon by the poison, it is soon replaced by the development of a new layer in the exsudation poured out ; a process which implies but a moderate hy- perasmia, and leaves no traces in the struc- ture of the j)art. While, if the direct action of the poison involve all the coats of the organ, it may give rise to a more or less extensive (and generally fatal) perforation. The intermediate degrees of this action are followed by a set of appearances which, with great differences in particular poisons and in- dividual cases, may be summed up as follows. The vascular changes consist chiefly in the production of an intense congestion or hyper- asmia. The blood-vessels thus injected com- municate to the mucous membrane a colour which takes every conceivable shade, from in- tense red to almost black. In the latter case, the microscope will often show that the blood is coagulated within the vessels, and here and there forms patches of hsemorrhage externally to them. The exsudation which accom- panies this congestion, renders the mucous STOMACH AND INTESTINE. 415 membrane swollen, soft and relaxed ; — a change which is generally due to the in- terstitial effusion of a large quantity of bloody serum. A similar fluid is also poured out into the interior of the organ in variable quantity ; and its effusion is generally attended with the detachment of the sloughs previously caused by the direct action of the poison. The ex- sudation also often distends the submucous areolar tissue, so as to separate the muscular and mucous tunics from each other. Some- times the former of these two tunics is only rendered paler and more yielding than na- tural. But in other cases, the whole parietes of the organ ultimately become converted into a rotten, brown, or reddish mass, in which scarcely any structure is distinguish- able. The details of those changes by which the moderately inflamed gastric membrane returns to a healthier state, are equally va- riable with the preceding. The separation of one or more flat sloughs lays bare what may be regarded as an ulcerated surface. The establishment of suppuration on this surface precedes the formation of the reparative tissue. When fully developed the latter substance exhibits the ordinary fibrous structure of ci- catrix. And since the process of exsudation previously extended to some little distance from the ulcer, the margin of the cica- trix blends gradually with the surrounding healthy mucous membrane ; while its base generally exhibits similar gradations of structure with the subjacent tissues. The subsequent contraction of the new tissue may materially alter the shape of the organ, and diminish its size. Indeed, where there has been much loss of substance at one point, it may even cause a more or less complete ob- struction or occlusion of its cavity. In dysentery, although the morbid changes appear to begin in the follicles, and often predominate here, still the relation of these structures to the process is far less intimate and specific than in typhoid fever. The dysenteric state may rather be regarded as an intense in- flammation of the whole of the mucous mem- brane; which engages these closed sacs with a rapidity and severit}' that seem to be not more than proportionate to their vascularity, and to the facilities which, as it were, their very construction offers to the exsudative process.* The morbid appearances chiefly affect the large intestine; and generally exhibit an in- crease in severity from the coecum towards the anus. In a subordinate degree, however, they not unirequently involve the adjoining segment of the ileum. The process begins as an enlargement of the solitary follicles of particular parts of the Dowel, which is quickly followed by appear- ances of inflammation in the adjacent mucous membrane. Red, swollen, and injected streaks are seen occupying the most projecting parts of some of the transverse folds of the bowel. * See p. 357. et seq. And on examining these streaks, we find that the epithelium is here and there raised from the subjacent tissues; either as a grayish flake, or as a semi-transparent vesication enclosing serum. Beneath this cell-growth is the raw and denuded mucous membrane; w hich is softened, reddened, and infiltrated (especially in its sub- mucous areolar tissue) with a bloody serum, that easily exsudes on making pressure. The above change soon extends, from these isolated streaks, to larger portions of the mu- cous surface ; so as to involve, not only the projecting folds of the bowel, but also their intervening depressions. The detached epi- thelium, which has a dirty gray colour, be- comes mixed with the subjacent reddish exsudation. The latter is generally thick and glutinous : but is sometimes of a denser and more croupy consistence ; which permits it to be detached and expelled as a more or less perfect cast of the inflamed segment of the bowel. The mucous membrane itself acquires a pale, or dirty-red, or even somewhat yellow- ish, colour; as well as an increased thickness, and a pulpy gelatinous consistence. The sub- mucous areolar tissue beneath it also becomes infiltrated with an exsudation that has the characters of bloody serum ; its enlarged fol- licles ulcerate or rupture ; and its interstices are here and there raised by effusion into protuberances, which give a mammillated aspect to the free inner surface of the intes- tine. In 'extreme cases, these projections multiply, enlarge, become confluent, and thus proportionally thicken the whole texture. These changes are usually accompanied by a more or less considerable dilatation of the intestine; the cavity of which contains, in addition to a large quantity of gases, a mixture of fasces, blood, epithelium, and lymph, in va- riable proportions. An increase in the intensity of the above ap- pearances rapidly converts the inflamed mem- brane into a sloughy or mortified mass. Prior to this event, it becomes dark red, brown, or almost black, from congestion and extravasa- tion of blood. Where less ecchymosis is ori- ginally present, and the blood poured out undergoes alterations after its effusion, it fre- quently offers a dirty gray or almost greenish colour. Subsequently to the separation or dissolution of the sloughy membrane, the de- nuded submucous tissue may be seen occupied by black masses of altered and coagulated blood, and by more or fewer of the vascular trunks formerly distributed to the destroyed tissues. And at this stage of the process, if not pre- viously, the adjacent muscular and peritoneal coats exhibit every evidence of their sharing in the disease. The former becomes infiltrated with blood, or serum, and of a dark, gray, or ash-coloured hue. While the peritoneum loses its smooth and shining appearance, ac- quires a dirty reddish colour and an injected state of its vessels, and often has its surface visibly occupied by a more or less purulent or sero-purulent exsudation. In extreme cases, these changes bring about an adhesion of the diseased bowel to neighbouring segments of 4-16 STOMACPI AND INTESTINE. the large or small intestine. The lymphatic glands connected witli the diseased intestine are also altered ; becoming swelled, injected, and of a red or bkiisli-red colour. These al- terations seem chiefly due to their irritation. The changes by which the diseased portions of intestine are restored to a healtliier state, of course vary with the intensity of the pro- cess, and with the e.xtent to which it has pro- ceeded. Thus, in slighter cases, the process is one of mere resolution. While, after the occurrence of sloughing and loss of sub- stance, the reparative act is much more imper- fect. It is effected by the development of a cicatrix ; which is gradually formed in the suppurating ulcer that is left by the detach- ment of the gangrenous portion of mem- brane. This cicatrix, though similar in structure to that noticed in the typhoid process, is very different both in its amount and arrangement. Its smooth (and apparently serous) surface often has to fill up the intervals of the irregular islands or isthmuses of mucous membrane which are left by the process of sloughing ; and hence the latter are often seen as thick projecting nodules, surrounded by a basis of new tissue. The base of the cicatrix extends to a va- riable depth in the subjacent coats of the bowel ; and, in chronic cases, often forms a thickened base, that sustains an ulcer of long standing and variable size. Finally, the great loss of surface which the cicatrix replaces, concurs with the two preceding circumstances to render its subsequent contraction of great influence on the sha])e and diameter of the bowel. Thus the ordinary situation of the sloughs in milder cases — on the projecting folds of the mucous membrane — seems at least a partial explanation of the frequency with which the contracted cicatrix takes the form of a cord or fold, itself more or less trans- verse to the axis of the tube, and hence very liable to cause obstruction of the canal. Ulceration constitutes a frequent termina- tion of the various inflammations of the alimen- tary canal. In this tube, as in most other parts of the body, it is associated with inflam- mation, chiefly as a secondary result ; which is conditionated, not so much by mere inten- sity of the process, as by a certain slow and chronic rate of its progress Thus in many of the abnormal conditions already alluded to, the sloughing occasioned by rapid and violent inflammation is often replaced by this inter- stitial mode of destruction, during the subsi- dence of the earlier and more acute sym- ptoms. While, in milder and more chronic cases, it occurs independently of the gan- grenous process. How far it is due to the vascular disturbance which inflammation pro- duces ; or to the direct effects of the ex- SLidation ; or finally, to a mere increase of the ordinary destructive absorption, or a decrease of assimilation; — it would be irrelevant to this sketch to inquire. The specific ulceration of typhoid fever has already been mentioned, as well as the secon- dary ulceration to which it often gives rise. The ulceration of tubercle and of cancer of the canal will be hereafter alluded to ; as being essentially due to the metamorphosis of certain deposits in the tissues of the organ, and to the reaction excited in the latter by their presence. Hence we need here only enumerate one or two of the remaining forms of ulceration most frequently seen in the stomach and intestines. It is but rarely that we find ulcerations of the tube which can be attributed to mecha- nical causes. In certain instances, however, the mere pres- sure of a neighbouring tumour, or of some diseased viscus, results in this process. But in such cases, the access of ulceration is usually preceded by the occurrence of exsu- dation and adhesion, which limit the amount of original substance it removes, and thus to some extent obviate the danger of its per- forating the walls of the tube. The impaction of solid masses in the canal more frequently leads to such a result. In rare instances, these masses find their way into the canal from neighbouring organs ; as is the case with gall-stones. In still rarer cases, they seem to be formed solely by the concretion of the liquid contents of the canal; resulting in intestinal calculi. In most instances, however, they are due to the in- troduction, from without, of various foreign bodies ; such as cherrj'-stones, pins, needles, or nails. In all cases, the ulceration depends, not only on the size, but also on the shape and surface, of the mechanical irritant. The most familiar examples of such ulceration are seen in the vermiform appendix ; where it is not uncommon to find perforation produced by an impacted mass ; which, on examination, proves to be some one of the small solids just alluded to, encrusted with rough calcareous matter, that has been derived from the con- tents of the canal. Ulcer of the stomacli.^\n the stomach and the first portion of the duodenum, the ulcera- tive process is often present in a peculiar form : namely, that which is usually called the simple or perforating ulcer. Of these two epithets, the first refers to the slight ap- pearances of inflammation often present in the neighbourhood of such ulcers ; the last, to the frequency with which they extend to such a depth, as to perforate all the coats of the organ. The size of these ulcers varies from that of a fourpenny piece, to that of a crown piece, or even larger. Their shape is usually circular; sometimes elliptical: occasionally, however, more irregular. In some instances,, this irregularity of outline is due to the fusion of two or more neighbouring ulcers into one, by an extension of their adjacent raargins.^v, But in a majority of cases, only single ulcers are present. Ac. The ulcer is generally situated, either in the neighbourhood of the pylorus, or near the lesser curvature of the organ : more rarely in front than behind ; and least frequently of all, . in the cardiac sac. STOMACH AND INTESTINE. 417 The mucous membrane in the neighbour- hood of the ulcer is sometimes a little swollen’: and the immediate margin of the excavation is often indurated and raised above the level of the adjacent mucous surface. But it offers no other appearances worth mentioning as indicative of inflammatory reaction in the con- tiguous tissues. The mode in which the ulcer penetrates the various tissues is somewhat characteristic. The smooth, sharp and vertical edge by which it passes through the mucous mem- brane, and reaches the submucous tissue, is here exchanged for a less regular one ; which forms a circle of smaller diameter than the opening in the mucous coat. In like manner, when the ulcer has gradually eaten its way through the muscular coat, it reaches the peritoneal coat, at a point which about occu- pies the centre of this smaller circle. Hence, the whole depth of the ulcer forms a cone ; the base of which is at the free or internal surface of the stomach, while its apex occupies the peritoneum. The latter membrane is scarcely ever destroyed by mere ulceration, except in those instances in which it has previously been strengthened and defended by an exsudation of lymph. Where this has not been deposited, the peritoneum becomes converted into a yellow slough ; the rupture or detachment of which gives rise to perforation of the sto- mach, and allows its contents to escape into the abdominal cavity. The process by which the gastric ulcer ori- ginates is at present unknown. Rokitansky thinks it probably begins as a haemorrhagic erosion, or a circumscribed slough ; and that it gradually extends by its basis throwing off a succession of laminated sloughs, or exlolia- tions. Some such process he has indeed observed in a few instances. On the other hand, if we may venture to regard that ulcer of the duodenum which sometimes occurs in severe burns, as analogous to the gastric ulcer, we should probably find reason for con- cluding, that the ulcerative process may some- times occur, without being preceded by he- morrhage, sloughing, or any appreciable ex- sudation, in the situation of the affected part.* The cicatrization of such ulcers may take place at almost any stage of their course. The precise details of its occurrence vary with the amount of destruction which has preceded it. Where the destructive process has been limited to the mucous membrane, there is little more than a condensation and thicken- ing of the subjacent areolar tissue ; which ul- timately forms a scar that has a shape similar to the ulcer. But where the muscular coat has been partially destroyed, its remaining la- mina, and the subjacent peritoneum, are gene- * See Pathological Transactions, vol. i. p. 258, for an instance brought forwai'd by Mr. Prescott Hewett ; where one of these ulcers seemed to be commencing as “ a slight depression in the surface of the mucous membrane, which in their neigh- hourhood presented some traces of increased vascularity.” Siipp. rally more or less folded or crumpled up, so as to bring the margins of the ulcer nearer to each other. Hence the resulting cicatrix has a much more irregular form ; and often con- tracts into a kind of thickened cord, with radiating extremities, which seriously affects the shape and diameter of the whole organ. The amount of contraction thus iin pressed upon the stomach varies, other things being equal, with the size and shape of the ulcer. The extension of the ulcerative process would always end in perforation, were it not this event is, in most instances, to .some extent guarded against by the occurrence of adhe- sion. From what has been already stated, it is evidently very doubtful whether the ulcer originates in an inflammatory state. And in many cases, it certainly seems devoid of all the ordinary appearances of inflammation during its progress. But it is often accom- panied, not only by swelling and induration of its mucous margin, but by exsudation and hanleiiing at its base, and by adhesive inflam- mation of the neighbouring tissues. Thus the peritoneal coat at the bottom of the ulcer becomes inflamed, and pours out upon its free surface a stratum of coagulable lymph; by means of which the stomach may become united to any adjacent viscus. In this man- ner the liver above the organ, or the pan- creas behind it, may become attached to the outer surface of the stomach, at a point cor- responding to the situation of the ulcer in its interior. But the more mobile diaphragm and anterior wall of the belly are less fre- quently the seat of such adhesions. The adhesion does not, however, replace the loss of substance in the gastric coats. And hence, in many of these cases (just as in adherent wounds of the stomach, attended with much loss of its parietes) the mucous membrane around the edges of the ulcer becomes prolapsed and protruded into it ; and thus comes into contact with the surface of the adhesion at its base. The substance of the adhesion itself may either ultimately become converted into a cicatiix : or it may be gra- dually drawn out by the constant traction wdiich the stomach exercises ; so as to form a hollow funnel-shaped tube, that is lined by a smooth surface having the a[)pearance of a serous membrane. The efficiency of the adhesion, as a means of [jrotection against [)erforation, varies wdth its situation, and still more with its structure. Where it is a mere thickening of a delicate fibrous netw'ork by inflammatory lymph, as is generally the case when it occupies the omentum, it is of little avail in this respect. While where the exsudation possesses a fibro- cartilaginous character, such as is often seen in the adhesions which unite the stomach with the liver, it forms a much more efficient protection against such an event. But in many instances, a continuance or renewal of the ulcerative process attacks and destroys the new tissue itself : and either penetrates the viscus (pancreas, liver, or spleen) E E 418 STOMACH AND INTESTINE. to which this is attached; or, by extending laterally, and opening into the peritoneum beyond the margin of the adhesion, leads to [jerforation. Ihemorrhage to a considerable extent generally occurs at some stage or other of the ulcerative process. In the earliest periods of the idcer, this hmmorrhage seems to proceed chiefly from smaller vessels. But after tlie coats of the stomach have once been penetrated, the larger vessels which run on its exterior surface become very liable to be attacked, erotled, and laid open. The haemor- rhage thus (jrodiiced is a frequent cause of death in this disease. The peritonitis i>ro- duced by perforation is, however, still more frequently fatal. Lieniery. — A peculiar ulceration of the fol- licles of the large intestine has been described by Rokitansky, umler the name of licnlcry. Like other ulcerations of this segment of the canal, diarrhoea is a constant symptom of its presence. The process begins by a disten- tion of the follicles, which is accompanied by a dusky-red injection of the vessels on and around their summits. The contents of the follicle next suppurate ; and are discharged from the resulting “ follicular abscess,” through an ulcerated or ruptured opening in the summit of the follicle itself. The follicle thus emptied is next removed by a process of ulce- ration ; the limits of which subsequently ex- tend, so as to form a round or oval ulcer, which has the size of a pea or a small bean. The mucous membrane at the margin of these ulcers is relaxed; and of a pale, grey, or livid colour. And the cellular tissue which forms their base exhibits similar appearances, which are sometimes combined with the various re- sults of slight extravasation of blood. The subsequent enlargement of these ulcers in various directions, and the fusion of several into one which may thus be brought about, constitute a secondary ulcerative process, which often lays bare a large surface of the submucous or muscular coat. The bases of these irregular secondary ulcers present cha- racters like those of the primary ulcers Just mentioned. Like the dysenteric process, this follicular ulceration increases in intensity from the coecum onwaixls towards the rectum. And in acute cases, it sometimes extends upwards into the ileum. Hypertroj)hy. — The hypertrophy generally described by authors as one of the abnormal conditions of the intestinal canal probably in- cludes, under one name, a variety of states ; which differ widely from each other, both in their nature and results^ ( 1 .) That thickened state of the tunics of the tube which is generally found behind an ob- struction of gradual origin or long standing, is the best (if not the only) instance, to which we can really ajtply the word hypertrophy ; in its strict sense of an excessive nutrition of tissue. Here the propulsive powers of the tube have to struggle against the increased resistance which is offered by the constricted or obstructed part : and this increased activit}' results in an exalted nutrition of the unstriped muscular fibres, which materially adds to their bulk. Such a true hypertrophy of the mus- cular coat may be seen in certain cases of .simple stricture of the rectum or oesophagus. And a similar condition is not unfrequently associated with the scirrhous constriction of the pylorus ; as a moderate hypertrophy of this tunic over a large part of the stomach. But a careful examination into the minute anatomy of this hypertrophy would generally show, that it can hardly be regarded as due to a mere exalted nutrition of previously ex- isting tissues. On the contrary, even in those instances in which it appears, to the naked eye, almost limited to the circular fibres of the muscular coat, the microscope often reveals evidence of a more extended change. The neighbouring submucous areolar tissue is always infiltrated with an exsudation, in larger quantity, and of more gelatinous consistence, than the nutritional fluid proper to the part. The partitions of areolar tissue by which the bundles of the unstriped fibres are normally separated from each other, are in- creased both in solidity and bulk. And, finally, the fibre-cells themselves not only present a more variable, as well as a generally increased size ; but are in many places sur- rounded by a more or less perfect layer of what seem to be developmental forms of these structures. (2.) In other cases of what is often called hypertrophy, a more partial and imperfect pro- cess of the same kind appears to take place, incidentally to the exsudation of a plasma, which may doubtless be referred to an in- flammatory origin. In such instances, an examination of the tunics of the canal gene- rally shows all of them to be more or less in- filtrated with a proteinous substance ; which renders them much thicker, whiter, and more resisting than natural. Mingled with this de- posit, we often find an unusual quantity of the unstriped muscular fibre. But it is not al- ways easy to verify the exact amount of true muscular hypertrophy that has taken place. For the exsudation, which generally predomi- nates in the submucous and subserous coats, has also a great tendency to involve the fibrous sheaths of the various bundles of the unstriped fibres; and is thus capable of com- municating to the muscular coat an increased thickness, which by no means implies a pro- portionate hypertrophy of its characteristic fibres. The author is inclined to conjecture, that, in these instances of interstitial exsudation, the muscular fibres are capable of being af- fected in either of three ways. In some in- stances they seem to be really hypertrophied ; a process which is possilily the indirect result of the immovable and thickened condition ot the tube, being such as to demand increased contractions, and stronger muscular struc- tures, in order to effect its various move- ments. In a second class of instances, they t STOMACH AND INTESTINE. 419 seem to be but little affected. Finally, in others — and especially in those cases injwbich the copious exsudation has subsequently con- tracted, so as to diminish the calibre of the tube, — the muscular fibres themselves seem to undergo a process of atrophy, which ends in their complete disappearance. (3.) The above remarks may serve to illus- trate a brief allusion to a third (and very fre- quent) variety of wdiat is called hypertrophy of the digestive canal, in which it is still more dif- ficult to determine the exact change that has taken place. In these cases an albuminous plasma exsudes into the coats of the canal ; either pretty equally throughout ; or with a more or less marked preference for the sub- mucous or subserous areolar tissue, and with marks of inflammation in the neighbouring mucous membrane or peritoneum respectively. When examined under the microscope, this albuminous plasma generally exhibits all the appearances which attend the abnormal de- velopment of fibrous tissue. But the fibres thus developed as the product of a diseased (and often an inflammatory) action, offer marked differences in their structure and ar- rangement from those of the normal areolar tissue among which they originate. While, as regards the changes undergone by the latter or healthier texture, it is often impossible to decide whether it has been augmented or hypertrophied ; or whether it has not rather experienced such an interference with its nu- trition, and such a loss of its substance, as amounts essentially to its atrophy. Folyin. — The tumours which have received the name of polypi agree in the common character of projecting into the cavity of the digestive canal, by means of a peduncle or stalk of variable length, that attaches them to its walls. Their size varies from that of a pea to a pigeon’s or hen’s egg. They are almost always covered by the mucous mem- brane : in the submucous areolar tissue beneath which they appear to be generally formed. It can scarcely be doubted that the shape of these polypi — like that of the papilliform tumours on the external integuments — is sometimes determined by a definite arrange- ment or development of the plasma out of which they are constructed. It is, perhaps, chiefly in this way that isolated malignant growths under the mucous membrane so fre- quently assume the pedunculated or polypoid form. But it seems certain that, in manj^ instances, their form is partly the result of a mechanical traction, such as the muscular contractions of the alimentary canal itself might exercise on almost any small tumour projecting from its mucous surface. The pe- dicle* ot the tumour is thus continually drawn out and lengthened. And the intus- * The movements of the intestines upon each other often seem to exert a similar meclianical in- fluence on tumours or deposits attached to their peritoneal surface. susception of that segment of intestine from which this pedicle arises, sometimes affords a remarkable testimony of the mechanical ac- tivity of the bowel. The interior of the non-malignant polt’- piforni tumours generally consists of a more or less completely developed fibrous tissue. In some cases, however, they contain a mass of adi[)ose tissue, which causes them to re- semble appendices epiploicte. In very rare instances, their contents approach the amor- phous character, and friable consistence, of a tuberculous deposit. And finally, they some- times constitute true mucous polypi ; which are distinguished by their lobulated form, their great vascularity, and their erectile and dilatable texture. The various small tumours which occa- sionally occupy the submucous tissue of the bowel scarcely require any separate descrip- tion. Cysts are comparatively rare in this situation. Fibrous, or fihro-cartilaginous masses are less infrequent. The latter rarely become the seat of a process of true ossi- fication. The inorganized earthy matters oftener found in their interior are formed, either by obsolete tubercle, or by the cretified contents of old abscesses, the pus of which has undergone a partial absorption. Tubercle. — The digestive canal is more frequently the seat of tuberculous deposit than any other organ of the body, the lungs only excepted. The pulmonary tubercle is, however, far more frequent than the intestinal. And the latter is not only generally preceded by the former ; but is rarely seen to any ex- tent, before the tuberculous matter deposited in the lungs has already reached the stage of softening and suppuration. The different segments of the canal are affected by it in the following order of fre- quency : the lower part of the ileum; the coscum; the large intestinegenerally; theupper part of the ileum ; the jejunum ; the duode- num ; and (very rarely) the stomach. Both forms of tubercle are met with in the intestinal canal. In a vast majority of in- stances, none but the crude, yellow, or caseous tubercle is detected. But in cases in which the disease has taken an unusually chronic course, the grey granulations are sometimes met with. The latter appear gradually to as- sume the caseous form ; the change beginning at their centre, and extending thence to their circumference. The deposit usually begins by' engaging the agminate and solitary follicles of the low'er third or half of the ileum ; filling and distend- ing their cavities with crude tubercle. A marked (and often intense) redness of this segment of the bowel usually accompanies the deposit; and remains, as a more or less distinct hyperseraia, during the remaining stages of the process. The caseous tubercle contained in these follicles next undergoes the process of soften- ing. The summit of the sac bursts or ulcerates; and its contents escape into the cavity of E E 2 420 STOMACH AND INTESTINE. the canal. The follicle itself is thus either evacuated or destroyed : and its situation is then occupied by a small excavated ulcer, va- rying in size from a millet-seed to a pea. This primary ulcer now becomes the seat of a process of secondary ulceration, which extends its size in the two directions of width and depth. Its superficial extension causes several of the small primary ulcers to become fused into one ; and sometimes widens the resulting secondary ulcer, so as to form a patch of ulceration that more or less encircles the bowel. Its vertical pi ogress successively engages the submucous and muscular coats, and thus finally reaches the peritoneum. The latter membrane, if not strengtheneil by the lymph of adhesive inflammation, now sloughs or ruptures; with the result of a fatal perfo- ration. This extension of the ulcerative process, and the means by which it is effected, together constitute the chief characteristics of tuher- cidar disease in the intestinal canal : and render the loss of substance it brings about in the walls of this tube, strictly analogous to that by which it excavates the tissues of the lung. The base and margins of the tubercu- lous ulcer have a ragged swollen appearance; are surrounded by a gelatinous infiltration ; and are themselves the seat of an interstitial deposit of cheesy tubercle. The softening of this deposit, and the suppuration of the ori- ginal tissues in which it is entangled, continu- ally increase the size of the ulcer ; and the inflammation thus produced tends as continu- ally to increase the deposit of new tubercle. Hence the tuberculous ulcer assimilates, so to speak, the adjacent tissues to itself: and is never bounded by healthy or heterogeneous tissues ; like those which adjoin the gastric ulcer, or the specific follicular ulcer of the typhoid process. As the tubercular ulceration extends, the intervening submucous tissue, even where hi- therto healthy, generally becomes the seat of a similar deposit and destruction. Hence, in well marked instances of acute intestinal tuberculosis, these ulcerations occu])y a large proportion of the affected surface of bowel ; leaving only small insulated patches, or fungous projections, of the original mucous membrane. And in extreme cases, they may even remove this tunic from a large con- tinuous segment of the bowel. The cicatrization of such ulcers is rarely seen, except in cases where the process has ceased in one part, while it has still been going on in another. In such instances, the removal of the softened mass already present ceases to be followed by any further interstitial deposit of fresh tubercle in the margin of the ulcer ; and a plasma, which exsudes on the bare and ulceratefl surface, is ultimately developed into a cicatrix of the ordinary structure and appearance. The subsequent contraction of this cicatrix is of course proportional to the loss of substance which it has had to replace. The zonular direction of the previous ulcer often gives it a form more or less approaching that of a cord or imperfect septum ; which lies transversely to the axis of the tube, and materially narrows its calibre. In rare instances, the cicatrix contains fragments of the cretaceous or other varieties of obsolete tubercle. Cancer. — Cancer affects the intestinal canal under all three of its chief forms ; namelj', scirrhous, medullary, and colloid or areolar cancer. And even its villous and epithelial varieties are occasionally present. The latter is, however, very rarely met with. In most instances the cancerous growth is at first seated chiefly in the submucous are- olar tissue; fiom which it gradually advances towards the inner and outer surface of the canal, so as ultimately to involve the whole of its coats. But the three forms of cancer fall with various degrees of intensity on different parts of this areolar layer. 'J'he scirrhous vari- ety begins in its deepest stratum ; and in those fibrous septa of the subjacent muscular bun- dles which are connected with it. The areolar or colloid variety chiefly affects the middle and looser laminte. While the medullary and the villous variety generally occupy the immediate neighbourhood of the basement membrane of the mucous tunic. Finally, in the e[)ithelial variety, there seems to be a definite metamorphosis of all the histolo- gical elements of the mucous membrane itself. Those rare instances in which the cancer seems to begin in the subserous areolar tissue are in reality cases of cancer of the perito- neum ; which membrane they almost always involve in its visceral reflexions (omentum and mesentery), as well as in some parts of its parietal latnina^.* The cancerous growth is generally primary ; but is sometimes secondary to a deposit in some neighbouring organ. In the latter case, the intestinal canal may either be involved by a mere extension of the disease from abso- lute contact ; or it may be affected through the intervention of the lymphatic glands and ves- sels. The first of these contingencies may be illustrated by the way in which the stomach is sometimes involved in a cancerous tumour of the liver : the second, by the far more nu- merous instances, in which the large intestine becomes cancerous, as the result of similar disease occupying the neighbouring lymphatic glands. The above varieties of the cancerous growth occur with very unequal frequency. The scirrhous is by far the most common, the medullary less frequent, and the colloid or areolar rarest of all. And while the former !s usually primary, the two latter are more fre- quently secondary ; or are often admixed, in varying proportions, with what was originally a scirrhous growth. In the latter instances, the scirrhus is sometimes said to have under- gone a transformation into medullary cancer. * Comp.'ire Art. Peritoneum. 421 STOMACH AND INTESTINE. But it is very rarely, if ever, that such a me- tamorphosis really occurs. In general the process thus designated consists merely in the deposit of new cancerous matter within, and especially around, the scirrhous mass ; and not in any true metamorphosis of 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 jiart. 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 resem'dance to the scirrhous deposit, that it seems worth while to enumerate the chief points of con- trast between them. Of these w^e 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 tw'o 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 evenl3’ 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 cai ti- laginous ; that of the hypertrophy is yellower, tougher, and more elastic. 4. The mus- cular substance is involved in hypertroph}' chiefly by the atrophy or enlargement of its bundles, w'ithin 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 ahvays offering the cell-forms charac- teristic of cancerous growth, in some part or other of its mass. Thus, for instance, even w'here 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 wdthin the meshes immediately around this harder nmss w’ill 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 membi'ane, 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 lieen enumerated in speaking of the differential diagnosis between it and hy pertrophy 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 com|)letely 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, the distention anil vascular disturhancc undergone by the latter gradually effects its disorganization. Its epi- thelium becomes detached; its surface ulce- rates or sloughs ; and more or less hoemor- rhage is e-Kcited. At this time, if not before, the cancerous process is generally so far mo- dified, as to give rise to the dejiosit 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 cotfee-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 jierforation of the organ. But this event is sometimes prevented by the adhesion of the |)eritoneal 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. Tlie 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, [lale, and ex- tremely delicate ; and their narrow outline is here and there bulged by persistent develop- tnental cells. The gelatinous mass which tliey 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 the.se 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. Sh'iclure of the intesthie. — 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, it.s 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 S|)eedily 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 hypertroph}-; 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 cause.s 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 inc- didlary fungus, or the deposit of a colloid or areolar mass upon the surface of the ulce- rated stricture, may of course increase the olistruction 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 arrangetl 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 sympathetic, 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 siile 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, th.oracic, 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 sitle 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 i v 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 Soemmering, 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 between 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. (b) Ascending or Carotid Branch. — This branch may be regarded as a prolongation up- wards of the synqiathetic cord. It is sol't, 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 wliich pass along the canal with the internal carotid artery, the one being sitiiateil rather to the inner, the other to the ontcr side of the vessel ; they form numerous intercommunica- tions with each other, giving rise to what is termed the internal carotid jtlexus. (c) Fhartjngcal 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. (d) 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 chieHy distributed to the blood vessels, they were named by Soemmering 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. iSome filaments also unite with the superior laryngeal nerve. (c) Superior or long cardiac Nerve, named also the 6U|)erficial cardiac branch, varies in tiiickness, 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 oi'the sympathetic cord, and passes behind or in front of the inferior tli3'roid 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 larymgeal nerves, and sometimes w'ith the phrenic. Not iinfrequently it is joined liy 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 jilexus. The nerve of the left side, after entering the chest, runs along the left carotid artery to the arch of the aorta, [lassing sometimes in front and sometimes behind that vessel. {f) 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 jiasses from the inferior extremity of the superior cervical ganglion, which sometimes seems to be prolonged dowmwards info it, along the surface of the rectus ciqiitis anticus major muscle, behind the carotid artery, and ratiier to the inner side of the pneuniogastric nerve, as i'ar as the inferior thyroid artery. Before sinking into the middle cervical gan- glion it sometimes divides into tw'O 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 su|)erior 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 oti 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 [tasses 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, wduch, in general, is more or less semilunar ; its convexity being ilirected downwards, its concave margin upwards. It is situated between tbe 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 laryngseal. {h) From the ganglion proceed several fine twigs, which surround the subclavian artery as well as its branches, forming small [)lexuses 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 ba.silar artery, upon the posterior cerebral and cerebellar arteries. Whilst situ- ated within the canal in the ti'ansverse ])ro- 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 vertebrae, 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 ple.Kus 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 b}' 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. 1 1. 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, rai'ely 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 * llemoire siir I’extremite cephalique du grand Bvmpalhetique dans riiomme et les aiiimaux mam- miferes. Par M. I. jM. Bourgery. Comptes Kendus, vol. XX. intercostal nerve : these are commonly double, sometimes three, short, and pretty strong. {b) Branches of small size pass fioin the ganglia to the descending aorta, forming a plexus around it ; others pass to the pul- monary and oeso[)hageal 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 vertebr®. 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 froin 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 cavify 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 coeliac 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 crus of the diapliragin. 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. Tlie 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. — {b) Branches also |)ass otffi'om the ganglia to the aortic, spermatic, renal and superior liypogastric plexuses. — (c) 42G SYMPATHETIC NEEVE, Krause describes branches as passing across the bodies of the vertebrae, forming a com- iminication between the ganglia of ojiposite sides. IV. Sacral portion of the Gangliated Cord. — The sacral [)ortion of the sympathetic cord is situated towards tlie 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 tlie 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 coininunica- tion [)ass 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 SVMPATHETIC. A. In the Head. — The chief plexuses of the synqrathetic which exist in the head are the internal carotid plexus, cavernous, and external carotid. There are also |)resent in dirterent 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 carotiil aitery during its passage through the carotid canal. The as- cending branch of the superior cervical gan- glion, as was already stated, diviiles into two portions, one of which passes along the outer and anterior aspect of the artery, while the other lies on the inner and [tosterior a.spect of the same vessel. The external portion is chiefly- concerned in the formation of the carotid plexus, the inner in forming the cavernous jdexus. 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, — (a) Two or three filaments of communica- tion with the sixth pair of nerves ; they join the nerve as it passes %long 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 ami passes to the ciliary ganglion, or to the spheno-pala- tine. (l>) Great or deep Petrosal Nerve. — This branch, commonly termed the deep branch of the Vidian nerve, may be regarded as passing from the fifth pair to the sympathetic, or vice versa. Regartling it as the latter, it may be de.scribed 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 terjninates in the ganglion of Meckel. In the interior of the pterygoid canal, the two nerves are merely placed side by siile 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 sup[)lied 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 tow’ards 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, {b) 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, (c) Communi- cating filaments with the ophthalmic ganglion, one or two in number, emerge from the an- terior part of the cavernous plexus, and enter the orint on the inner side of the ophthalmic division of the fifth nerve, either ending di- rectly in the posterior border of the ophthalmic ganglion, or joining the long root derived from the nasal branch of the ophthalmic. Occa- sionally one filament enters the posterior bor- der of the ganglion, the other along witli the long root derived from the nasal branch. (<7) One or two delicate filaments have been observetl by Fontana, Hirzel, and Arnold to pass from the cavernous plexus to the pituitary body. As this body is said to receive filaments from the sympathetic cords of either side, it has been supposed to hold the same rela- tion to these as the ganglion impar or coccy- geal ganglion at the opjto.site extremity of the trunk. Bock regarils the filaments, however, which have been described as entering tiie pituitary body, as solely destineil for its ves- sels, terminating in their coats. Weber states that he has examined with the greatest care SYMPATHETIC NERVE. 427 the sup|)osed communication between the S3'mpathetic and pituitary body in mammals and birds, but failed to convince himself that any such communication exists, (e) Arterial branches, accompanying the branches of the internal carotid arteries. These are described by Chaussier* and Ribes as passing not only along the anterior and middle cerebral arteries, but also along the branches of the ophthalmic artery, forming minute plexuses upon them. One of these plexuses is described by these authors, as well as by Rnself and Langenbeck, as accompanying the central artery of the retina into the eyeball. Ribes has also traced filaments irom the cavernous plexus upon the anterior communicating arteries, by means of which the sympathetic cords of either side are united, there being at their point of junction a small ganglionic enlargement ; this arrangement has been denied by Lobstein and others. 3. External Carotid Plextis. — The external carotid plexus formed as already mentioned by the union of the nervi modes from the su- perior cervical ganglion, commences at the origin of the external carotid artery. There is sometimes a ganglionic enlargement present, which from the fact of being situated at the point of bifurcation of the common carotid artery, was termed by Arnold the intercaro- tidean ganglion. The external carotid plexus extends along the artery of the same name, encircling it with nun)erous branches, on which frequently occur .small ganglionic en- largements. At its commencement numerous communications are formed between it and the branches of the glosso-pharyngeal and vagus nerves, which go to form the pharyngeal plexus. It also forms connections with the upper cardiac nerve, and, higher up, as it passes with the artery through the parotid gland, branches are given off for the supply of this organ, and also others, which become connected with the facial and auriculo-tem- poral nerves. Offsets are sent from it along the divisions of the external carotid artery, forming a number of plexuses around them, which are named according to the arterial branches which they accompany. One of these accompanies the superior thyroid artery into the substance of the thyroid gland ; it communicates with the superior laryngeal and upper cardiac nerves. Another accompanies the ascending pharyngeal artery, and is inti- mately connected with the pharyngeal plexus. The lingual plexus encircles the artery of the same name, giving off filaments to the sub- lingual gland, and forming communications with the lingual branches of the glosso-pha- ryngeal nerve. The facial plexus surrounds the facial artery and its branches, one or two filaments, which accompany the submental artery, pass to the submaxillary gland, and * Memoires de la Societe Med. d’Emulation, vol. vii. p. 97, t Tiedemann’s Zeitschrift. fur Phj'siol. band ii. p. 227. communicate with the ganglion of the same name. Small plexuses accompanying the occi- pital and posterior auricular arteries seem to terminate chiefly in the parotid gland. Most of the branches which accompany the super- ficial temporal artery appear to pass along the arteries going to the ear and eyelids. Nu- merous filaments, presenting here and there ganglionic enlargements, proceed upwards on the external carotid artery as far as its divi- sion into the temporal and internal maxillary arteries ; many of these appear to terminate in the parotid gland, while others accompany the temporal and internal maxillary arteries. Of the latter, one is described by Arnold as emanating from the plexus surrounding the middle meningeal artery, and passing to the posterior part of the otic ganglion. Subsidiary branches accompany the diflerent divisions of the internal maxillary artery. From the external carotid plexus several filaments pass downwards upon the common carotid artery, forming, with others derived from the middle cervical ganglion, a plexus around the vessel, which accompanies it and forms communications with the inferior thyroid plexus, as W'ell as with the superior cardiac nerve and cardiac plexus. B. Thoracic Plexuses of the Sympathetic. — The plexuses occurring in the thora.x in con- nection with the sympathetic are the cardiac plexus, and the plexus surrounding the thoracic aorta : it also contributes to the formation of the pulmonary and oesophageal plexuses. 1. Cardiac Plexus. — The cardiac plexus is formed by the union of the cardiac branches of the sympathetic already described, and by numerous filaments derived from the recurrent laryngeal, as well as from the vagus nerve it- self; a branch from the descendens noni nerve accompanies the superior cardiac nerve, and also terminates in the plexus. The superior cardiac nerves, the branches from the recurrent laryngeal and vagus nerves terminate in the upper part of the plexus ; the middle cardiac branches of both sides terminate commonly in its middle portion, while the inferior cardiac branches, with some of those derived from the recurrent laryngeal nerve, end chiefly in its lower part. The plexus is asymmetrical, and is situated in the upper part of the tho- racic cavity, extending from the transverse portion of the arch of the aorta to the base of the heart : it consists of a widely-meshed netw'ork of moderately fine filaments, some presenting a greyish, others a more or less white appearance. About the centre of the plexus, behind the arch of the aorta and in front of the bifurcations of the trachea, at the point of division of the pulmonary artery there is commonly present a ganglionic en- largement. This which is termed the cardiac ganglion (Ganglion cardiacum Wrisbertrii), presents a gre_\ish colour and irregular shape, generally more or less angular or oblong, and measures from one to two lines in length. That portion of the cartliac plexus which is 428 SYMPATHETIC NERVE. formed 1))^ tlie brandies of the sympathetic which pass down in front of the arteria in- nomiiiata on the right side, and tlie arch of the aorta on the left side, corresponds to what is termed by some the superficial cardiac |)lexus, while the portion formed by the iiranches of the sympathetic and vagus which descend behind the arcli of the aorta between it and the tracliea, is termed the deep cardiac plexus. The branches whicli proceed from the cariliac plexus are tlie following: — («) Nmiierous filaments pass off from tlie upper part of the plexus and surround the arch of the aorta, as well as the large arterial trunks which sjiring from the same, {b) Others pass along tlie right and left pulmonary arteries, and terminate in the pulmonary plexus, (c) Offsets are also sent along the coronary ar- teries, forming the anterior and posterior coronary plexuses. The anterior coronary plexus is chiefly derived from the superficial portion of the cardiac jilexus, and accom- panies the anterior or l ight corotiary artery and its divisions ; the posterior coronary plexus, chiefly derived from the left side of the dee[)er portion of the cardiac plexus, is situateil at first behind the aorta and pulmo- nary artery ; it then passes in front of the left division of the ptdmonary artery to the base of the heart, and reaches the posterior co- ronary artery, around which it forms an inter- lacement of filaments. Numerous filaments are distributed by it to the left side of the heart, especially to the left ventricle : the filaments of the anterior coronaiy plexus are chiefly distributed to the right ventricle. The nerve filaments which leave the coronai-y plexuses do not all accompany the branches of the coronary arteries, as was formerly sup- posed; by far the greater number of them run separately from the vessels, and are distributed to the muscular substance of the heart. As regards the arrangement of the nerves on leaving the coronary plexuses, they appear to be much more numerous on the ventricles than the auricles. The filaments distribut- ed to the former are very numerous ; they are directed from the base to the apex of the ventricle; those on the anterior surface passing obliquely downwards from left to right, those on the posterior surface from right to left ; they thus in general cross obliquely the direc- tion of the muscular fibres of the ventricles, and often also that of the blood vessels. Where they cross the latter, especially in the heart of the young ox, they appear to bifur- cate, so as to enclose the vessel in a loop ; and at this point there is frequently, as is re- presented by Dr. Lee, a small enlargement which occasionally contains ganglionic matter.* In their course along the surface of the ven- tricles, neighbouring filaments frequently unite, there being here also small ganglionic enlarge- ments. Accoriling to Dr. Lee there are dis- tinctly visible on the anterior surface of the * Dr. Lee, on the Ganglia and Nerves of the Heart. Phil. Trans. 1849. young heifer’s heart about ninety of these ganglia or ganglionic enlargements. The left ventricle appears to be more abundantly sup- plied with nerves than that of the right side : on the former they can be traced, extending from base to apex, on the surface of the latter they generally extend but a little way down, when they sink into the muscular substance. 2. Plexus of the Thoracic Aorta. This con- sists of delicate filaments which are derived from the thoracic portion of the gangliated chain of the sympathetic ; several filaments also pass between it and the oesophageal ]>lexus. Above, it is continued into the cardiac plexus, from which it derives some branches, and below it accompanies the ve.ssel through the aortic o[)ening in the diaphragm, to terminate in the cceliac plexus. C. Abdominal Plexuses of the Sympathetic — The abdominal [ilexuses of the sympathetic are larger and more numerous than those oc- curring in any of the other cavities of the body. They correspond in number with the branches of the abdominal aorta, and accom- pany them in their course to the different viscera. From the plexuses occurring on the larger arteries, off-sets pass, which form a number of subsidiary plexuses upon the smaller vessels. The chief abdominal plexuses are the cceliac, superior mesenteric, renal, inferior mesen- teric, and siqwrior and inftrior hypiogastric plexuses. I . The cceliac, solar, or epigastric pilexus is the largest of the plexuses of the sympa- thetic. It is situated in the upper part of the cavity of the abdomen, on both sides of the aortic opening in the diaphragm, extending across the anterior part of the aorta, and is covered in front by the stomach. It sur- rounds the cceliac axis, and extends down- warils as far as the origin of the superior mesenteric artery. It usually contains two ganglia; these present a somewdiat crescentic form, and have on this account been termed the semilunar ganglia. They are situated one on each side of the plexus towards its upper part, and are commonly surrounded by a num- ber of smaller ganglia. The solar plexus receives the s|)lanchnic nerves, also some branches from the posterior gastric plexus of the pneumogastric ; it likewise receives fila- ments from the plexus which has been de- scribed as surrounding the thoracic aorta, as well as others from the three or four iqiper lumbar ganglia. The offsets from the plexus present the same plexiform arrangement as the plexus itself, and are named according to the arteries which they accompany ; they are the phrenic, or diaphragmatic, superior coro- nary, hepatic, splenic, and renal plexuses. {a) The diaphragmatic plexuses are two in number, a right and left, and consist of several delicate filaments derived from the upper part of the semilunar ganglia. They often present several small ganglionic en- largements, and accompany the diaphragmatic'’ arteries, sinking with them into the muscular,' SYMPATHETIC NERVE. 420 substance of the diaphragm, where they com- municate with branches of the phrenic nerve. (6) The superior coronary plexus accom- panies tlie left coronary artery of the stomach, along its upper border, and is distributed to the anterior and posterior walls of the organ, its filaments uniting with the branches sup- plied b}' the pneuinogastric nerves, chiefly with those which are distributed to tlie posterior wall of the stomach. It extends to the pyloric orifice, where it joins branches of the hepatic plexus. (c) The hepatic plexus, of considerable size, ascends along with the hepatic artery ; it receives some filaments from the pneumo- gastric nerve, and also communicates, as has been already mentioned, with the superior coronary plexus of the stomach. Branches leave it for the duodenum and head of the pancreas ; and others pass with the right gastro- epiploic artery, along the greater curvature of the stomach, forming the inferior coronary plexus of the stomach. On entering the trans- verse fissure of the liver, the hepatic plexus divides into a right and a left portion, which accompany the divisions of the hepatic artery and vena ports, ramifying upon them — an off- set from the hepatic plexus passes to the gall-bladder, along with the cystic artery. (d) The splenic ple.xus surrounds the artery of the same name, passing with it and its branches to the spleen. Offsets pass from the splenic plexus to the pancreas, and to the stomach, wliich form the pancreatic and left gastro-epiploic plexuses. 2. The sieperior mesenteric Plexus appears as a prolongation downwards of the coeliac plexus, and is the largest of the offsets fur- nished by it : it also receives some filaments from the right pneumogastric nerve. It sur- rounds the superior mesenteric artery', form- ing for it a close plexiform sheath, and sends offsets along its branches, which accompany them as they pass between the layers of the mesentery to the duodenum, small intestine, coecum, and ascending and transverse colon. The highest of these unite with the nerves which pass along the pancreatico-duodenal ar- tery, while those which are distributed to the transverse colon communicate with the nerves derived from the inferior mesenteric plexus. The nerves which accompany the arteries to the intestines present at first a plexiform arrangement but in their course through the mesentery, several of them are seen to run alongside the vessels, sometimes separated a short distance from them. Communicating branches pass between them in the same way as between the arteries. On reaching the intestine they enter it at the part where the mesentery is attached, and dividing into finer twigs, soon disappear in the substance of its coats. Many appear to become lost in the muscular coats, while some may be traced through these, ending apparently in the mu- cous coat, or in the sub-mucous cellular tissue. 3. Renal Plexuses. — The right and left renal plexuses are formed by branches which pro- ceed from the coeliac and superior mesenteric plexuses, and likewise derive filaments from the aortic plexus. In their course along the renal arteries they receive filaments, which are sent off from the smaller splanchnic nerves, and others from the superior lumbar ganglia. Several small ganglia are present in the nerves of the renal [dexus. They divide along with the bi'anches of the renal artery, each arterial branch being generally accompanied by two nervous twigs. Fi'om the renal plexus fila- ments are sent off, which, with others derived from the coeliac and phrenic plexuses, form the supra-renal plexus destined for the supply of the supra-renal capsule. 4. Spermatic Plexuses. — The right and left spermatic plexuses consist of some delicate nervous filaments, which are derived from the renal plexus. As they pass downwards with the spermatic arteries, they receive some ad- ditional filaments from the aortic plexus, and appear to give off several filaments to the ureters ; in their course to the testes they are connected with the nerves which accompany the vas deferens. In the female they are dis- tributed to the ovaries and uterus. 5. The aortic ple.xus, situated along the abdo- minal aorta, and extending from the superior to the inferior mesenteric arteries, consists of filaments tlerived from the superior mesenteric and renal jdexuses. In its course downwards it also receives branches from the lumbar gan- glia : it terminates in the inferior mesenteric and superior hypogastric plexuses, and also, as has been already stated, contributes to the formation of the spermatic plexus. 6. Inferior JSIesenteric Plexus. — The inferior mesenteric [tlexus, formed by the left lateral portion of the aortic plexus, is less dense and less distinct than the superior plexus of the same name: its fibres present, however, the same whitish aspect and firm consistence, and sometimes have small ganglionic enlargements developed upon them. It accompanies the inferior mesenteric artery, dividing along with it, and forming secondary plexuses around its branches, which pass with them to the de- scending colon, sigmoid flexure, and upper half of the rectum. Above, the branches of the inferior mesenteric plexus form communi- cations with those derived from the superior mesenteric, and below, with others derived from the superior hypogastric plexus of the lel't side. 7. Hypogastric Plexus. — The hypogastric, a single plexus, situated in front of the fifth lumbar vertebra and promontory of the sacrum, between the two common iliac arteries, pre- sents an irregularly quadrilateral and flattened aspect. Nervous branches, about twelve in number, pass down to it on each side from the aortic plexus, and additional filaments are derived from the lumbar ganglia. From the plexus small offsets proceed along the common iliac arteries, and a few join the hemorrhoidal filaments derived from the superior mesenteric plexus : it then divides into a right and left 430 SYMPATHETIC NERVE, portion, which are continued forwards along the sides of tlie rectum, to form the inferior hypogastric plexuses. 8. Inferior llypognstric Plexuses. — These consist of a right and left plexus, formed in the manner just mentioned ; they contain several small ganglia. Filaments are likewise sent to them from the sacral ganglia, as well as from two or three of the sacral nerves. These plexuses are situated upon the sides of the rectum, the plexuses of opposite sides being united by cross branches. From the plexus proceed the following branches, {a) Some hcemorrlioiilal branches : these are termed the inferior ha2inorrhoidal nerves ; they are very delicate ami unite with the superior hemor- rhoidal branches derived from the inferior mesenteric plexus, and go to supply the rec- tum. {b) Vesical plexus . The nerves [)roceed- ing to this plexus come from the lower and anterior portion of the inferior hypogastric plexus, and pass to the sides and lower part of the blatlder. The nerves are most numerous near the neck of the organ, and have several minute ganglia developed upon them. From the neck numerous branches pass upwards on the sides of the bladder, and are chiefly dis- tributed to its muscular coats ; a few, however, may be traced through the muscular to the mucous coat. From the vesical plexus, fila- ments are given off’ which pass to the vesiculae seminales, around which they form a plexus ; others pass to the vas deferens and ramify around it, communicating on the spermatic cord with the nerves of the spermatic plexus, while a third portion passes to the prostate gland. The branches which pass to the latter are of considerable size, and form connections with the plexus around the vesiculte seminales. Some of the branches sink into the substance of the gland, others are continued forwards to the erectile tissue of the penis, constituting the so-called cavernous nerves, or cavernous plexus. From these branches are distributed to the membranous portion of the urethra. They then continue forwards, passing beneath the arch of the pubis to the root of the penis. By Miiller*, they are divided into nervi caver- nosi minores, and nervus cavernosus major. The former penetrate the crus of the corpus cavernosus penis, and spread out upon the cells of the erectile tissue : the latter runs along the dorsum of the penis between the tlorsal artery and vein. About the middle of the penis it divides into a number of branches anil forms communications with the dorsal branch of the pudic nerve : some of the branches accompany the dorsal vessels and unite with those of the opposite side ; the greater portion, however, penetrate the corpus cavernosum and are distributed to its sub- stance. 9. Uterine Plexus. — The nerves destined for the supply of the uterus are derived from the up|)er and posterior part of the inferior hypo- gastric plexus, and also from the superior * Ueber die organisehen Nerven der erectilen mannfichen Geschlechts-organe. Berlin, 1836. plexus of the same name. They pass between the folds of the broad ligament in company with the uterine vessels ; before reaeliing the uterus, however, the greater portion of them separate from the vessels, and are distributed to the substance of the neck and body of the organ. The portion derived from the superior hypogastric plexus appears to be chiefly dis- tributed to the fundus of the organ ; a fila- ment also passes, according to Dr. Beck*', from the ovarian artery to the fundus of the uterus. Besides the branches above mentioned there are others, according to Dr. Beck, derived also from the hypogastric plexus, which assume a plexiform arrange- ment around the vessels, and are characterised by the presence of several minute ganglia. Fig. 280. Small ganglion from the posterior wall of the cervix of an impregnated uterus of the Cow. Minute Anatomv. — The branches of the sympathetic nerve present to the naked eye certain characters which, more or less, dis- tinguish them from the proper cerebro-spinal nerves. They have a dull greyish-white ap- pearance, diff’erent from the white shining aspect which characterises the nerves belong- ing to the other class. This appearance is better marked in some parts of the nerve than in others, and is best seen in the branches which accompany the blood-vessels. By Valentin this gray appearance of the sym- pathetic nerves was attributed to the presence of the ganglionic corpuscles : this, however, as Remak observed, cannot be the case, inas- * On the Nerves of the Uterus. Phil. Trans. 1846. . i SYMPATHETIC NERVE. 431 much as the ganglionic corpuscles are not dis- tributed throughout the whole extent ot the nerve, but are confined to certain limited parts. Remak believed it to be due to the presence of structures termed by him oi'ganic nerve fibres : Volkmann and Bidder also believed it to be owing to a peculiar set of fibres, different, I'ig. 281. 1. Tubular nerve^fibres from the thoracic portion of the sympathetic cord in Man. 2. Fibres of Remak {pelatinous fibres') and fine tubular nerve-fibres, from the nerves of the spleen in the Sheep, however, from those of Remak. Whether it be due to tlie fibres of Remak or not, it seems to be, at least, best marked in those branches of the sj mpathetic in which these fibres are most abundant. The sympatlietic also differs from the cerebro-spinal nerves in consistence as well as in its appearance, being much softer and more readily torn across than the latter. This may be partly due to the want of the strong distinct fibrous sheath possessed by the latter, and parti}' also to a difference in the character of the nerve fibres themselves. The nerve fibres of the sympathetic are moreover not arranged into distinct fasciculi, but lie together imbedded in a mass of fibrous tissue which accompanies them, serving the purpose of a sheath. As regards the constituents of the sympa- thetic nervous trunk, when a portion of one of the main cords is examined with a pow'er of 250 diameters, it is found to be composed of the following elements: 1st. Tubular nerve fibres ; 2nd. Structures which present a homo- geneous flattened appearance, and contain a number of oval nuclei imbedded in them at intervals ; and, 3rd. a quantity of white fibrous tissue. The tubular nerve fibres which are present in the sympathetic, differ much in point of breadth from one another. Some of them measure about to of an inch in diameter : their contents present the arrange- ment of double contour and axis cylinder which characterise the fibres occurring in the cerebro-spinal nerves. Besides these fibres there are others present which have also the character of the tubular fibre, but are much finer, measuring only from the -zrsfio the ■yJg-j- of an inch. They present distinct margins, but have a paler aspect than the above, and do not possess the double contour which is seen in the broader tubular fibres, and many of them often have a tendency to the formation of varicosities. When running in bundles they have, according to Volkmann* and Bidder, who first called attention to their anatomical characters, a yellowish grey hue instead of the white pearly aspect of the cerebro-spinal nerves. Sometimes the two sets of fibres are intermingled and run side by side with each other, at other times they run in bundles more or less distinctly separated. The number of fine fibres which are present much exceeds that of the broader or coarser variety. The two classes of fibres do not, how- ever, appear to be distinctly marked off from one another, there being present fibres w'hich possess partly the characters of the one and partly those of the other. When one of the finer variety is examined at the same time with one of the coarser variety, and the two com- pared, the points of distinction are sufficiently Fig. 282. Broader, or animal, and finer, or sympathetic, pri- mitive nerve-fibres, from the common trunk of the vagus in the Frog. (^Bidder and Volkmann.') marked, but a gradual transition from the fibres belonging to the one set to those belonging to the other may, in some parts of the sympa- thetic, generally he traced. The finer the nerve tubules are, the less distinctly do their contents appear to be separatetl into central portion or axis cylinder, and white substance of Schwann. 2. In regard to the structures No. 2. which have been mentioned as occurring in the sym- pathetic, Remak-|-, their discoverer, describes Die Selbstaiidigkeit des sjnnpathischen ISTer- vensystems von F. II. Bidder und A. W. V^olk- mann, Leipzig; 18-12 ; p. 19. et seq. t Observationes Microscopica?, &c. Berol, 1838. §§ 6. 13. 432 SYMPATHETIC NERVE. them as being destitute of a sheath, naked, transparent, almost gelatinous, as presenting a number of longitudinal streaks, and as break- ing up into delicate fibrils, which in their course present oval ddatations or swellings, and have moreover a number of round or oval cor- puscles arranged upon them at intervals- Apparently, the same structures have been described by llenle under the name of “gela- tinous fibres.” According to him they are flat homogeneous fibres, measuring from the 0'002'" to the 0'003'" in diameter, and cha- racterised by the presence of numerous nuclei, some round, others oval, their long diameter being directed in the longitudinal axis of the fibre. They are dissolved by acetic acid, the nucleus becoming at the same time more dis- tinct. The fibres in question are well seen in the branches of the sympathetic which go to the spleen or kidney in the sheep or ox, as well as in the trunk of the sympathetic nerve itself. In the former situations they appear as a more or less transparent, slightly granular, pale mass, and marked by indistinct longitudinal lines into fibres presenting a diameter of about __i_th to inch, and characterised by the presence of round, oval, or elongated nuclei. On the addition of acetic acid they swell out, becoming perfectly transparent and in- distinct, while at the same time the nuclei are brought more clearly into view. AVhen treated with tartaric or citric acid, the effect produced upon them is much the same : solution of soda also causes them to swell out and be- come indistinct, the nuclei being at the same time also rendered more or less indistinct. The nuclei generally measure about the lir-ij^th to the „,r^-gth of an inch in length, and about __'__th to the of an inch in breadth, presenting the same characters and behaving towards reagents in [the same manner as the nuclei occurring in most other tissues. They are much softer than the tubular fibres, and are not easily se[)arated from one another. In some parts of the peripheral branches ofthe sympathetic these fibres present a much smaller diameter, measuring about of an inch, are finer and distinguished with difficulty from the white fibrous tisstie present. In the nerve they are placed parallel to one another, and are seen, when the preparation is pressed between the glasses, running along each side of the tubular fibres, which latter seem to be im- bedded amongst them. They differ from the tubular nerve-fibres in their flattened ap- pearance, want of distinct margin, and in the effects produced upon them by reagents, but are especially characterised by the presence of their nuclei. They are most abundant in the more grey-looking branches of the sym- pathetic, and seem to be the cause to which this appearance is chiefly owing. Sometimes when one of the smaller filaments of the sympathetic is examined, it seems to be en- tirely composed of these fibres, no tubular nerve fibres being at first seen ; solution of soda, however, which, as has been stated, renders the gelatinous fibres transparent, brings into view more or fewer fine tubular fibres. There can be no doubt that in many parts of the sympathetic, especially in the branches distributed to the arteries, the fibres of Remak, or gelatinous fibres, make up the greater portion of their constituents, the tubular nerve fibres existing only in comparatively small numbers Sometimes more or less grey and white bundles of fibres may be seen running along- side each other : such an arrangement is not unfrequently seen in the branches of com- munication between the sympathetic and the spinal nerves. In such cases, while the white chiefly or entirely consists of tubular nerve fibres, the grey contains a large number of gelatinous fibres, and always in addition to these more or fewer fine tubular fibres. The gelatinous fibres are present in dif- ferent proportion in different |)arts of the sympathetic : they appear to be more abundant in the neighbourhood of the ganglia than in other parts and in the larger peripherical branches they also exist in considerable pro- portion, but in the final distribution of these they either do not exist at all or only in small number. They appear to be more abundant in the sympathetic of the higher animals than in that of the lower vertebrata. In mammals and birds they exist in considerable quantity: in amphibia, according to Kolliker, they are present but only in small proportion. In some fish, as in the common Ray, the sympa- thetic ganglia and branches contain a very large proportion of structures which agree with the fibres of Remak in some respects, such as in their relation to the ganglionic corpuscles and tubular nerve fibres, as well as by the presence of a number of small oval nuclei ; they differ from them, however, in not being so much affected by acetic acid and in being firmer : the number of tubular fibres occurring in the sympathetic is very small compared with the number of these struc- tures. 3. The quantity of vvhite fibrous tissue present in the sympathetic trunk and branches is generally considerable; the fibres are arranged in the longitudinal direction for the most part ; other fibres, which from their relation to reagents appear to belong to the yellow elastic tissue, encircle the nerve, binding together, as it were, its constituents. After addition of soda or acetic acid the circular fibres are well seen ; at the parts where they occur there is frequently observed a distinct con- striction, the nerve being swollen out above and below by the reagent applied. With res|)ect to the nerve fibres occurring in the sympathetic, many of them present undoubtedly the same characters as those occurring in the nerves of the cerebro-spina! system. It has been maintained that the sympathetic also contains fibres which differ in their anatomical characters from the fibres of which the latter class of nerves are com- posed, and which have been termed organic or vegetative nerve fibres. Ehrenberg appears to have regarded the fine varicose tubular fibres which are present in the sympathetic, as constituting the peculiar SYMPATHETIC NERVE. 433 organic nerve fibres. According to Purkinje *, the ganglionic nerve-fibres are much finer than those belonging to the cerebro-spinal system or animal fibres. He describes the latter as containing two substances, — an outer, which runs in the form of a tube through the elementary fibre immediately within its sheath, and an inner, which occupies the hollow in- terior of the former. The tubular sheaths of the elementary fibres of the ganglionic system contain, on the other hand, no double substance ; their contents are homogeneous, and appear to correspond to the axis cy- linder or central portion of the animal nerve- fibres ; their sheaths are much stronger than those of the nerve-fibres of the cerebro- spinal nerves, and resist mechanical influ- ences in a high degree. In the foetus the animal nerve-fibres cannot, according to Purkinje, be distinguished at a certain stage of their formation from those which are cha- racteristic of the sympathetic in the full-grown animal ; and hence he regarded the latter as a less highly developed stage of the former. Pappenheim also appears to have recognised the fibres describetl by Purkinje, as consti- tuting the peculiar fibres of the sympathetic system. According to Remakj-, the fibres which have been described above as the gelatinous fibres or fibres of Remak, constitute the pe- culiar organic or sympathetic nerve-fibre, all the tubular nerve-fibres being considered by him as belonging to the cerebro-spinal system. The fibres in question do not take their origin, according to him, from the cerebro-spinal centres, but arise from the ganglionic corpuscles contained in the different ganglia, and then run along with the tubular fibres sent to the sympathetic by the cerebral and spinal nerves. It has been disputed, however, whether the fibres described by Remak are entitled to the character of nerve-fibres, and are not rather to be regarded in the light of accessory struc- tures which serve as a sheath to the true or tubular nerve-fibres. Valentin J, who adopts the latter view, states that the fibres in ques- tion do not arise from the ganglionic cor- puscles themselves, as was believed by Remak, but are continuous with the nucleated sub- stance which forms the sheath or capsule of these bodies, and are thence prolonged upon the nerve-tubes, and are to be viewed as merely discharging the part of a protecting covering or envelope to the latter. They do not, according to Valentin, present the most distant resemblance to nerve-tubes, which could scarcely be the case were they in reality a mere variety of the same structures : in their microscopic character, on the other hand, they agree in every respect with certain * Muller’s Archiv. 1839, p. 203. Valentin’s Re- pertorium, band v. p. 78. See also Bidder and Volkman, op. cit. t Log. cit. j Ueber die Scheiden der Ganglienkngeln und leren Fortsetzungen, in Muller’s Arcliiv. 1839. Mso Valentin’s Eepertorium, band iii. p. 70. et :eq., and band v. p. 79., &c. Siipp. forms of white fibrous tissue, especially at certain stages of its formation ; and they are Fig. 283. From the semilunar ganglion of man. A. Ganglionic corpuscles included within their nucleated capsules. B. Ditto liberated. entirely'wanting, or occur only' in small num- bers, in the main cord of the sympathetic, where the fibrous tissue is, as well as in many of the peripherical branches of the same, deficient. In the horse the fibres of Remak, which are present in the nerve-branches passing along the mesentery, were seen by Valentin to cease one or two feet from the point at which the nerves enter the intestine. Bidder* and Volkmann also appear to regard them merely as a variety of areolar tissue, observing that their anatomical characters are so different from the known elements of the nervous system as to exclude them from the character of true nerve-fibres. In the mammalia, according to these authors, the areolar tissue which is interposed between the different organs is very abundant, and in this class of animals the fibres of Remak also abound. In birds, where the quantity of such areolar tissue is smaller, these fibres are not so nu- merous ; and in the cold-blooded animals, where there is very little interposed areolar tissue, the fibres of Remak either fail al- together, or they exist only in very small numbers. From this it would appear that they regard the fibres of Remak as holding the same relation to the tubular nerve-fibres that the areolar tissue holds to the different organs between which it is interposed. They also agree with Valentin in regard to the very marked resemblance between these fibres and white fibrous tissue at certain stages of its formation, and accordingly adopt the view that they are rather to be regarded as white fibrous tissue which has not reached its full development than true nerve-fibres. They find, moreover, as will be afterwards noticed, * Op. cit. § 12. F F SYMPATHETIC NERVE. RU that the increase in point of thickness of the nerves leaving a ganglion over those which pass to it is clue, not to the presence of a greater number of the fibres of Remak, as might be e.xpected were these true nerve- fibres arising from the ganglionic corpuscles, but to an increased number of fine tubular fibres. Kdlliker * likewise agrees with the authors already mentioned in the view that the fibres of Remak are not to be regarded as true nerve- fibres, but rather as enveloping structures or sheaths to the tubular fibres. He believes, with Valentin, that they are not connected with the ganglionic cor[mscle itself, but with its sheath, and are thence continued along such of the tubular fibres as arise from the corpuscles, forming for them a protecting enve- lope or sheath. The capsules of the ganglionic corpuscles are, according to Kdlliker, a species of fibrous tissue; and so also tlie fibres of Remak, which are continuous with them, must be regarded as partaking of the same nature. Again, whilst, on the one hand, these fibres are very abundant in the neighbourhood of the ganglia, in the finer branches, on the other hand, they are much fewer in number, and in the ultimate distribution of the nerve do not exist at all. Similar structures have also been observed by him accompanying the very fine branches of some of the spinal nerves ; such, for example, as those going to the skin, while, at the same time, they are not to be found in the main or larger branches of the same. The chief grounds, then, on which it is held that the fibres of Remak are to be re- garded as enveloping structures, and not as true nerve-fibres, are, 1. the anatomical dif- ferences between these and the true or tu- bular nerve fibre ; 2. their resemblance to certain varieties of white fibrous tissue ; 3. their connection with the sheaths of the ganglionic corpuscles, and not with these bodies themselves; 4. their absence in the final distribution of the nerve ; 5. the in- crease in the thickness of the nerves leaving a ganglion being due, not to an increased number of fibres of Remak, but of fine tubular fibres. On the other hand, it has been stated that the anatomical difference between the tubular fibres and the fibres of Remak is not a suf- ficient ground for believing that the latter are destitute of the properties of nerve-fibres. All the nerve-tubes in the embryo, even after it is considerably advanced in development, present much the same character as these fibres, and even after birth nuclei may be occasionally found existing in them. Again, as noticed by Todd and Bowman, the nerve- fibres in the olfactory nerve resemble the fibres of Remak in containing nuclei, and also in the want of double contour, as well as in their soft homogeneous appearance. Wiien a nerve is divided, and a portion of it removed, * IMikroskopisclie Anatomie Oder Gew'ebelehre des Menschen, von A. Kolliker; Leipzig, 1850; zweiter band, p. 530. the structure by which its continuity is re- stored presents much the same appearance as the fibres of Remak, and this for some time after the part supplied by the nerves has, to a certain extent, regained its functions, showing tliat impressions may travel along structures not differing from the fibres in question. In reply to the second objection, it is stated that the difference between the fibres of Remak and white fibrous tissue is such as to preclude the notion of the one being a mere variety of the other. In the third place, it is said that it is by no means determined that the fibres of Remak are connected merely with the capsules of the ganglionic corpuscle, and, supposing they were so, that these also may be possessed of the properties of nerve-tissue. As regards the relation between the gan- glionic corpuscles and the fibres of Remak, the tubular nerve-fibres wliich leave the ganglia may not unfrequently be observed to have structures running along each side, which present the same characters as the fibres of Remak ; sometimes only a single row, at other times a doul)le row, of nuclei are placed along each side of the tubular fibre, indicating one or two fibres of Remak. These, on being Fig. 284. A r A. Ganglion corpuscles from one of the spinal ganglia in the Blouse, a, corpuscle continuous with a nerve-tube, h. (Mag. 250 diam.) E. Ditto from tbe Gasserian ganglon of the Cat. a, capsule of corpuscle and nerve-tube ; 5, cell- membrane of ganglion-corpuscle. c. Cell freed from capsule. traced inwards to the ganglionic corpuscle, are found to be distinctly continuous with the capsules of these bodies. When the ganglionic corpuscles are seen separately from one another it is found that these structures are connected only with such of the corpuscles as are still included in their capsules, those which are isolated from their capsules never having any such attached to them (see A, b, and c.jfg-. 284.) In their general aspect, as well as in their relation towards reagents, the fibres of Remak correspond with the capsules of the corpuscles ; moreover Kolliker has seen and distinctly figures the capsules of these bodies as directly continuous with the fibres of Remak. As regards their dissimilarity to white fibrous tissue, there can be little doubt that when SYMPATHETIC NERVE. 433 charactei'istic specimens of either are examined the difference is sufficiently marked ; yet in Fig. 285. some parts of the branches of the sympathetic in the higher animals it is difficult to limit the two species of tissue, and between the most characteristic of the fibres and many em- bryonic tissues the most marked resemblance exists. In the ultimate distribution of the sympathetic there seem to be, as Kdlliker observes, none but fine tubular fibres present. If, then, the fibres of Remak be kept out of consideration, as not being possessed of the properties of nerve-fibres, are there any fibres in the sympathetic which can be regarded as differing in their anatomical constitution fl ora those occurring in the nerves belonging to the cerebro-spinal system? In 1842 Bidder and Volkmann described particularly the distinc- tion in point of structure between the tubular fibres, which have been mentioned as being present in the sympathetic. They measured the tubular fibres, and found that while some of them had a diameter of 0‘00046 to O'OOOoS of an inch, others measured only 0‘00012 to 0‘00022; and between the two sizes they observed no fibres of intermediate breadth. They also measured the branches which enter and those which leave the ganglia in the frog. The latter were found to exceed the former in point of thickness, which could only be at- tributed to the addition of structures arising in the ganglia, and on examination they ob- served that the increase in thickness of the one over the other was due to the presence of a greater number of tubular nerve-fibres belonging to the finer variety ; and hence it was concluded that these are the peculiar organic or sympathetic fibre. The coarser variety they regarded as arising in the cerebro- spinal centres, while the fibres belonging to the finer variety always, according to them, take their origin in the ganglionic system. They describe these fibres as being about half the diameter of those belonging to the cerebro- spinal nerves ; they are further distinguished by their paleness ; the absence, under all cir- cumstances, of the double contour, and the small quantity of curdlike contents which they present even when examined some time after death, and by their yellowish-gray colour when in bundles. The distinctions between the broad and fine tubular fibres, as given by Volkmann and Bidder, were denied by Valen- tin, who stated that the fibres of these au- thors were merely fibres of Remak. Reichert, on the other hand, confirmed the observations of Bidder and Volkmann as to the difference in point of size and structure between the cerebro-spinal nerve-fibres and the sympathetic or organic fibres. The description which is given by Remak of the gelatinous fibre does not, as Volkmann and Bidder maintain, apply to the fibres which they have described ; they are much finer, ten times finer, than the cerebro-spinal fibres, whereas the fibres of Bidder and Volkmann are generally only a half narrower than these fibres. The relations of the two structures towards reagents as well as their general characters are also very dif- ferent. Kolliker agrees with Bidder and Volkmann that there are nerve fibres in the sympathetic which are not derived from the cerebro-spinal system, but arise from the ganglionic cor- puscles ; he farther confirms the observation of these authors, that all the fibres which arise in the sympathetic belong to the finer variety of tubular fibres, and that they present the characters which they were described by Bidder and Volkmann as possessing ; he de- nies, however, that they are peculiar to the sympathetic system. Fine fibres agreeing with these in structure arise, according to him, in the cerebro-spinal system, as well as in the sympathetic. Again, the diameter of the coarser and finer varieties of the tubular nerve fibres is by no means so strictly limited as Bidder and Volkmann believed, there being transitions from the finer to the broader or coarser variety. Besides occurring in the sym- pathetic, they are likewise present in the anterior and posterior roots of the spinal nerves, especially in the latter; and in the brain and spinal cord they exist in large num- bers. Another objection to the views of Bidder and Volkmann as to the peculiar na- ture of these fibres is derived from the fact that it is by no means uncommon for the broader tubular fibres to divide into finer fibres during their course to the periphery, becoming narrower and narrower, and at the same time losing their distinct double contour; and hence in their ultimate distribution they consist almost entirely of fine fibres, which cannot be distinguished from those described by Bidder and Volkmann as constituting the peculiar fibres of the sympathetic system. Volkmann himself now admits that the dis- tinction between the broad or animal nerve- fibre and the fine or organic is by no means always strictly defined, and also that the broad tubular or animal fibres, in their peri- pherical distribution, assume the characters of the others. It would appear, then, as Kdl- liker maintains, that there is no absolute dis- tinction between the fibres of the sympathetic and those belonging to the cerebro-spinal system ; the difference is merely one of rela- tion and degree : while the nerves of the latter system consist chiefly of broad tubular fibres, the sympathetic is composed of fine ones. F F 2 436 SYMPATHETIC NERVE. Ganglia. — The ganglia occurring on the sympathetic are, as has been already stated, very numerous, constituting the most distin- guishing character of this nerve. There are also ganglia |)resent on the posterior roots of all the spinal nerves, as well as on several of the cerebral nerves; and by many these are classified along with those of the sympathetic, constituting what has been termed the gan- glionic system of nerves. The ganglia present the appearance of nodules or swellings oc- curring on a nerve during its course. When e.xamined with the naked eye, they appear to consist of opaque and more or less pelliiciil portions, present a greyish colour, and are possessed of considerable consistence. Some- times they occur in the course of a single nerve, as is the case witli the ganglia in the |)osterior roots of the spinal nerves. The syni|)athetic ganglia commonly present the appearance of masses of various sizes connected with several nerve-branches which appear to pass oft' from tliem in different directions. The ganglia situated in dift'erent parts of the body are all more or less connectei.1 by means of bundles of nerve-fibres passing between them. As already noticed, many of them are arranged alongside the spinal column ; others are si- tuated on the different plexuses which are formed by the branches passing oft' from these, while numerous otliers of smaller size occur in the substance of the organs supplied by the sympathetic. All of them consist essentially of a number of bodies presenting peculiar characters and termed ganglionic corpuscles, and of nerve-fibres in more or less intimate connection with these. Ganglionic Cori^iiscles, ganglion-vesicles (Germ. GangUenlcngeln). — These bodies ap- pear to have been first noticed by Ehrenberg*, and were afterwards more fully described by Valentin. f They vary in size from the to the of an inch. Those in the ganglia of the cerebro-spinal nerves are generally con- siderably larger and not so delicate as those in the ganglion of the sympathetic. They commonly present a round or oval form; sometimes they are more or less pear-shaped. Their contents consi.st of a delicate clear fluid holding in suspension numerous finely granular particles, which give the cells a more or less grayish aspect. This substance is possessed of considerable viscidity, as shov/n by the fact that when removed from the corpuscle it does not separate into distinct particles, but remains coherent in a single mass which flattens out somewhat. Each of the ganglionic corpuscles contains a distinct rounded nucleus which in appearance resembles the corpuscle itself, only its contents are clearer. These measure from the goVoth to the of an inch in diameter, and are commonly situated rather towards one side of the cell. Withiti the nucleus there is commonly a third body, which presents a clear rounded a[>pearance like the * Poggendorf’s Annalen, band xxviii. p. 458., as quoted in Brim’s Anatomie. t Nova Acta, band xviii. p. 127., as quoted in Brim’s Anatomie. nucleus, and may be regarded as the nucleolus. Sometimes there are two such bodies present. In the ganglionic corpuscles there is also fre- quently contained a mass of pigmentary matter consisting of particles which are much coarser and darker than the rest of the con- tents. This mass is sometimes situated at a little distance from the nucleus, at other times it partly covers it, and occasionally it conceals it entirely from view. Its quantity varies much in different cells : it appears, as Kblliker observes, to be more abundant in the ganglion- corpuscles of old people than in those of the young. Sometimes he has observed it present in such quantity as to fill the entire cell. In the Gasserian ganglion of a man aged about sixty I observed several bodies present, which in size and shape corresponded with the gan- glionic vesicles : they appeared, however, to be less delicate, and presented a dark-brown colour, and in all probability were ganglionic corpuscles filled with dark pigmentary matter such as Kblliker notices. Connected with many of the ganglionic corpuscles are one or two delicate processes of different lengths, and presenting the same delicate finely-gra- nular appearance as the vesicle itself of which they appear to be a prolongation. In tlie corpuscles occurring in the ganglia these do not present the same branching character as they have been described to do in the brain and spinal cord by Purkinje, Remak, Hannover, and by Todd and Bowman, who in their de- scription of these bodies, which by them were termed “caudate nerve-vesicles,” hinted at the probability of the processes being continuous with nerve-tubes. The actual continuity of the process of the ganglion-vesicle witli the nerve- tube was, however, first observed by Kblliker* in the ganglia of the amphibia. He found that on tracing the process onwards from the cell it became continuous with a nerve-tube pre- senting distinct dark margins. The observa- tion of Kblliker in regard to the connection of the nerve-tube with the ganglion-corpuscle has since been confirmed by many other ob- servers, and especially by Wagner and others in the ganglia of the fish. Some of the gan- glionic corpuscles appear to be destitute of any such process ; others have a single process passing off from them, while others present two such processes, passing off at either extremity (A.G.y?g.286.). Occasionally the two processes pass off from a round cell, not at either extre- mity, but at a short distance from each other on one side of the body {Jig. 291.). The ganglionic corpuscles which are not connected with any process, or, as may be safely said, with any nerve-tube, have been termed by Stannius ^ aiwlar cells ; those from which one tube pro- ' ceeds are termed wiipolar, while the cells with which two such are connected are called by hiin_^. bipolar ganglionic corpuscles or cells. The^ nerve-tube which is connected with the uni-^ polar cell is always found to run periphcrically, ^ i. e. from the centre. In regard to the bipolat^" * Mikroskopisclie Anatomic, p. 508., zweitei^, band. ^ SYMPATHETIC NERVE. 437 cells, when the nerve-tubes come off at either them runs towards the periphery, the one at extremity, as they generally do, while one of the opposite runs towards the nervous centres. I’/g. 286. Ganglionic corpuscles from one of the spinal ganglia in the Say. In A, the granular contents reach quite to the margin of the vesicle; B, ganglion-corpuscle with a layer of clear round delicate bodies on the inner surface of its wall ; c, showing a clear space be- tween the granular contents and the cell-wmll, occupied bj' particles of oily matter similar to the contents of the nerve-tubes ; d, a corpuscle which has been treated with chromic acid ; E, ganglionic corpuscle of smaller size, with narrower nerve-fibre attached to it; f, one intermediate in size betw'een the larger and smaller corpuscles; G, apparent apolar and unipolar corpuscles; H, collapsed mem- brane of a ganglion-corpuscle ; j, liberated contents of the same. When both nerve-tubes pass off, not at op- posite extremities, but from one side of the corpuscle, they both run, according to Bidder, in the direction of the periphery. As regards the mode of connection between the ganglionic corpuscle and nerve-tube, the cell-wall of the former appears to be directly continuous with the membrane of the latter, while the contents of the vesicle seem to be prolonged down- wm’dsinto the nerve-tube, becoming continuous with its contents. The nucleated substance forming the capsule of the ganglionic corpuscle is also, according to Kblliker, prolonged along the nerve-tube which arises from the corpuscle itself (^fig. 288. and 289.). All the nerve-tubes which are thus connected with the ganglionic corpuscles in the ganglia of the sympathetic belong to the finer variety of tubular fibres already described. In the spinal ganglia, according to Kolliker, the nerve-tubes arising from the corpuscles are at first fine, mea- suring about O’OOlo — 0'0023 of a line ; but in their further course man}’ of them increase in diameter up to 0'003 — 0'004 of a line, or even to O'OOo — O’OOG of a line, so as to represent broad nerve-fibres, or fibres intermediate be- tvveen the broader and finer varieties. Most of the cells which are seen in ex- amining the ganglia of the mammalia belong either to the apolar or bipolar variety. It is pos- sible, however, that many of them, as Wagner, Robin, &c. maintain, although apparently apo- lar, are really uni|iolar or bipolar cells, from which one or both processes have broken off during the process of preparing them for ex- amination. That the bipolar cell exists in F F 3 438 SYMPATHETIC NERVE. man and other mammalia, is proved by the with the walls of the included ganglionic cor- observations of Schrceder van dcr Kolk in puscle, and appears to hold much the same A. Spinal ganglion from the Ray. (40 diain.) B. Portion of the same more separated. regard to the cervical ganglia of man, as men- tioned by Donders and Harting. Schaffner also describes a bipolar cell in the ganglion Gasseri of the sheep ; and similar cells have been observed by Corti* and Pappenheim in the acoustic nerve of the pig, and by Frey in the Gasserian ganglion of the cat. In the common trunk of the pneumogastric and sympathetic nerves in the middle of the neck, in the young calf, oval cells maybe seen which have distinctly attached at their peripherical extremity a nerve-fibre ; and some of them also appear to be connected with one at the opposite or central extremity. The different cells composing a ganglion are each surrounded by a more or less clear, homo- geneous substance, in which are contained a number of round or oval nuclei. These are seen to form a single or double row around the margin of the ganglionic vesicle, their long axis being directed in the axis of the cir- cumference of the cell {fig. 288.). Tliey are also seen upon the surface of the corpuscle (c, fig. 288.). Tills substance not unfrequently presents a more or less fibrous aspect, as if composed of spindle-shaped corpuscles. It re- sembles much (as has been already stated) the fibres of Remak. The nuclei measure from the to the ^„*^„th of an inch in breadth, and about ^th to , 5^00 th of an inch in length. The structure in question is closely connected * Kolliker’s Mikroskopische Anatomie, band ii. 519. Fig. 288. From the gastric ganglion of the Raj^ shewing ganglionic corpuscles embedded in a nucleated tibi'ous tissue. relation to it that the fibres of Remak hold to the nerve-tubes. It has been termed the capsule of the ganglionic corpuscle. The cap- sules surrounding the different ganglionic cor- puscles are also closely united to each other, so as to form a kind of framework, in the loculi of which the ganglionic corpuscles are placed (y?g.288.). It would appear also to be prolonged along the nerve-tubes connected with the gan- glionic corpuscles for some distance, forming for them an investment or sheath similar to that which it forms for the corpuscles them- selves. The quantity of this substance which is present varies in different circumstances. It appears to be more abundant in some cases than in others, and is commonly more so in the sympathetic ganglia than in those on the posterior roots of the spinal nerves. As regards the arrangement of the nerve- fibres in the ganglia, when one of the enter- ing branches in the ganglia of small animals, such as the mouse, is traced into the point at which it joins the ganglion, it is found to spread out somewhat, and soon breaks up into its component fibres. These separate from one another, running amongst the gan- glionic corpuscles, either singly or in bundles of two, three, or more. The nerve-fibres be- longing to one bundle leave it and join neigh- bouring bundles, so that a more or less com- plete interchange of the fibres contained in the different bundles takes place; and at the same time there is formed a sort of plexus or network, in the meshes of which the ganglionic corjjuscles are imbedded {fig. 287.). Some- times, as Valentin observed, one or more of the fibres of one of the entering bundles are seen to wind round the ganglionic corpuscles, and appear again to pass into another entering bundle, thus pursuing apparently a retrograde course. The fibres which thus surround the ganglionic vesicles were termed by Valentin umspinnende fasern ; whether they again really leave the ganglion in the direction in which they entered it, and in this way may be regarded as terminating in a looped arrange-^ SYMPATHETIC NERVE. 439 raent in the ganglion, it is difficult to deter- mine. Kdlliker*' has observed that the nerve- tube arising from a ganglionic corpuscle fre- quently makes one or two turns around it before pursuing its course towards the peri- phery ; and it appears probable therefore that many of the so-called unupinnende faseni may be of this description. That the nerve-fibres connected with the ganglia do not merely pass through it between the ganglionic corpuscles, as was formerly supposed, but enter into intimate organic connection with these bodies, either arising from them, or having these bodies developed upon them in their course from the centre towards the periphery, as seems to be the case with most of the bipolar cells, is quite certain. Aves. — In the bird the ganglia present much the same structure, both as regards the ganglionic corpuscles and nerve-fibres, as those of the mammalia. Reptilia. — In the frog, the animal in this class which has been most frequently ex- amined, the ganglionic corpuscles present the same general characters as those in the higher animals. The existence of apolar and uni- polar ganglionic corpuscles is much better seen in examining the small ganglia in the heart or bladder of this animal than in the ganglia of the mammal or bird. Bipolar cells have been described by Schiff; Valentinf has also de- scribed and figured bipolar ganglionic cor- puscles the nerve-tubes of which ran in opposite directions, one towards the centre, the other towards the periphery. They were found by him both in the small ganglia of the heart, and also in the ganglia occurring in the main chain of the sympathetic. The nerve- tube connected with these he describes as clear and transparent, differing from the broad nerve-fibres in its colour and general appear- ance, especially in its not presenting any oily contents, and thus appearing to belong to the fine variety of fibres. Kolliker describes the unipolar ganglionic corpuscles as being pyriform, and at their narrow extremity drawn out into a delicate process. This presents the same [lale and finely-granular appearance as the corpuscle itself, and measures from the to the , iluo-th of an inch in dia- meter ; after running a short distance from the ganglionic corpuscle it acquires a dark margin and slightly granular contents ; becoming, in short, a fine nerve-fibre (see fig. 289. a). Bidder has also observed in the ganglia of the heart of the frog bipolar cells, which, however, resembled the unipolar in the fact that both nerve-tubes ran in the direction of the periphery. In the ganglia of the frog there is a much smaller amount of the substance present, which has been described as consti- tuting the capsules of the ganglionic corpuscle, and there are also very few of the fibres of Remak. Pisces. — In certain animals belonging to this class, especially in the cartilaginous fishes * Mikroskopische Anatomie. t Valentin, Lehrbuch der Pliysiologie. Braun- schweig, 1848 ; band ii. p. 602. et seg. the 'connection between the ganglionic cor- puscles and the nerve-tubes is much better seen than in any of the preceding classes. In the torpedo and ray the bipolar variety of ganglionic corpuscles w’as first discovered by Wagner, and shortly afterwards by Robin. Similar observations were also made by Bid- der and Reichert, both as regards the car- tilaginous fishes, and, by the latter observer, in the cod, perch, and certain species of sal- mon, as well as in the pike.* In the common ray the ganglionic corpuscles, as occurring in the spinal ganglia, are generally more or less round or oval, and are much larger than in any of the higher animals. They measure from 4^th to the ^^th of an inch in dia- meter, and contain a more or less clear viscid fluid with finely molecular matter. On the addition of dilated acids or spirit, they be- come dark and granular. Each of the cells contains a clear round nucleus, in which there is also present one, sometimes two, nucleoli. The contents of the nucleus, like those of the cell itself, become dark and granular on add- ing the reagents above mentioned. In se- veral of the cells there are seen, apparently on the inner, surface of their wall, a num- ber of round corpuscles, generally clear and transparent, but sometimes more or less dark and granular. They measure about the of an inch in diameter, and seem, as Wagner and Robin describe, to form a single layer on the inner surface of the ganglionic corpuscles. The larger of the ganglionic corpuscles are generally more or less spheri- cal ; the smaller, on the other hand, present commonly a more oval sha|)e. Sometimes between the outer cell-wall and the contents of the vesicles there is, as Bidder describes, a clear space, varying in breadth, generally broadest at the points where the two nerve- tubes are connected with the corpuscle ; at other times this space does not appear to exist, the granular contents of the vesicle coming close up to the cell-wall (see a. and v.Jig. 286.). The wall of the corpuscle appears to be much stronger than that of those in the higher animals, and is distinctly prolonged at either extremity into the mem- brane of the nerve-tube, the two constituting one continuous structure, agreeing both in anatomical characters and in their relation towards reagents. When the ganglion-ve- sicle is ruptured, so as to allow its con- tents to escape, its cell-wall collapses more or less, and often ])resents the appearance of lines passing outwards towards the circum- ference, from a central point (ii. fiig. 286.) • this appearance is evidently due to folds in the membrane. In the clear space which has been mentioned as sometimes existing be- tween the cell-wall and the contents of the ganglionic corpuscle, there are often observed a number of particles, most abundant at the tvvo poles of the vesicle, which resemble in appearance the curd-like contents of the nerve- * Canslatt’s Jahresbericht, 1847, also Wagner’s Handwbrterbuch der Pliysiologie, baud ill. p. 361. et seq. F F 4 440 SYMPATHETIC NERVE. tubes, and are evidently continuous with the same (c, 286.). Sometimes the granular contents of the vesicle appear to be prolonged downwards into the nerve-tube Jig. 289.), Fig. 289. Ganglionic corpuscles from the gastric ganglion of the Torpedo. {After Wagner.) Sliowing, li, several of the cells still surrounded by the fibro-nucleated tissue, a, other cells de- nuded of it. while at other times, the oily contents of the latter reach quite up to the corpuscle, and seem either to become blended witli the granular contents of the same, or are pro- longed into the clear space. Wagner# be- lieves that the normal relation between the nerve-tubes and corpuscles is, that each pri- mitive nerve-fibre coming from the centre, retains its appearance of double contour up to the ganglion-cell, where its contents are interrupted by the finely granular matter of the latter ; at the peripherical extremity of the cell, the nerve-fibre commences in a quite similar manner. Thus then, according to Wagner, the oily contents of the nerve-tube cease on reaching the ganglionic corpuscle. Bidder-]-, on the other hand, regards the clear white space between the cell- wall anti the granular contents as a thin sheet of nervous matter, which serves as a connecting medium between the contents of the nerve-tube on either side of the ganglionic corpuscle. As regards the sym[)athetic ganglia in this animal, they apf>ear in some parts to be almost entirely composed of a fibrous structure and of a quantity of granular matter resembling, as Wagner and Robin observe, the gray granular matter of the nervous centres, and containing a number of bodies of a brownish- yellow granular appearance, which do not dis- * Ilandwbrterbuch der Pliysiologie, bandiii. p. 361. et scq. t Ziir Lebeii von dem Verliiiltnisz der Ganglien, kbrper zu den Nervenfasern, Leipzig, as quoted in Canslatt’s Jaliresbericbt, 1847. appear on addition of acetic acid. In other parts the ganglia contain corpuscles similar to those already described as occurring in the spinal ganglia, with the exception that they are in general perhaps somewhat smaller. They are imbedded in a fibrous structure, which seems to hold the same relation to them as the nucleated substance forming the cajisules of the ganglionic corpuscles in the higher animals. It is difficult to ascertain how far the ganglionic corpuscles in the ab- dominal ganglia are unipolar or bipolar ; ac- cording to Wagner, they are the same in this respect as the corpuscles in the spinal ganglia, being all bipolar ; one tube entering while another leaves the corpuscle. The nerve- tubes which are connected with them belong both to the broad and fine varieties ; in ge- neral, the narrower fibres are connected with the smaller corpuscles, the broader fibres with those of larger size {Jig. 290.). Ganglionic corpuscles from the 26th spinal ganglion of the Torpedo, drawn in outline in order to show the different size of the nerve-luhes. {After Wagner.) It has been already seen that it is almost certain that all the ganglionic corpuscles oc- curring in the ganglia on the posterior roots of the spinal nerves, at least in this animal, belong to the bipolar variety ; it remains to inquire whether all the nerve-fibres in the posterior root are connected with ganglionic corpuscles. When the ganglion, after addition of dilute solution of soda, is examined with a power of about 30 or 40 diameters, itis observed that while many of the fibres soon disappear among the ganglionic corpuscles, several of them can be traced from the point at which they enter the ganglion almost to its opposite extremity, without being connected with cor- puscles ; but I have never been able to trace them in this manner quite past the ganglion. Wagner, who counted the nerve-tubes con- tained in the posterior root of the nerve and also the ganglionic corpuscles, found that the number of each corresponded pretty closely, 441 SYMPATHETIC NERVE. so that he believes each of them is connected svith one of these bodies. Invertebrata. — The ganglionic corpuscles in the ganglia of the invertebrata appear to be the same in their essential characters as , those of the vertebrate animals. Will* re- cognises two kinds of ganglion-corpuscles in the lower animals. The one he describes as consisting of a membrane and nucleus, the space between the two being occupied by a clear transparent fluid, which becomes granular on the addition of water ; in the other variety there are imbedded in the clear transparent fluid numerous small round cells in which no nucleus is visible. The cells belonging to the former variety have always but one process attached to them which consists of a single tube, presenting no division so far as it can be traced, and thus corresponding to the uni- polar variety of corpuscle. In the second kind of corpuscles there are several such pro- cesses present ; the processes attached to some of these cells all run in one direction ; in others they pass oft’ at either extremity and run in opposite directions. In the leech, according to Bruch -f-, there are also two kinds of ganglion corpuscles. The one variety are round and are apolar ; the others are con- nected with nerve-fibres. The latter are situ- ated towards the lower part of the ganglia, and are more numerous than tlie former: they are more or less pyriform, their wider ex- tremity being directed outwards ; their nar- rower, terminating in a process, is directed towards the ganglia and the nervous cord. Peripherical ganglia, consisting of from one to six or seven cells, are always found at the points where the branches of the nerves di- vide. Ganglionic corpuscles were also seen by him in the interior of the nerve-tubes, and corresponding to the view taken by Bidder J of the constitution of the bipolar ganglionic corpuscle. Apolar and unipolar cells have also been described by Hannover and Leydig in several other invertebrate animals. From the fact that in such animals as the torpedo and ray, where the ganglionic cor- puscles are easily isolated from each other, they are all found to belong to the bipolar variety, Wagner, Robin, and Bidder believe that all the ganglionic corpuscles in other animals are also bipolar. Kolliker, on the other hand, while he admits that the bipolar cell is most frequent in the fish, maintains that the opposite is the case as regards the higher animals, most of the corpuscles in them belonging either to the apolar or uni- polar varieties; and so far as actual observa- tion goes, the views of Kolliker seem to be perfectly correct, inasmuch as, while apolar and unipolar cells are very frequently seen in these animals, the bipolar variety has been seen very seldom. It is possible, however, that many of these unipolar and apolar cells may, as Wagner and Bidder, &c. hold, be really bipolar cells, one or both nerve-tubes * Muller’s Archiv. 1844, p. 76. also in Canslatt’s Jahresbericht, ISl?. t Ibid. having been broken off during the manipula- tion required for submitting them to examina- tion. In the spinal ganglia of the ray the cells are very easily isolated from each other, whereas in the abdominal ganglia it is very difficult, owing to the amount of surround- ing fibrous structure, to isolate them. Now in the former only bipolar cells are seen, whereas in the latter, most of the cells, when isolated, appear to be unipolar and a|)olar, although it would appear from the observa- tions of Wagner and others, that they are all bipolar, like those in the spinal ganglia. In the higher animals, especially in the mam- malia, the ganglionic corpuscles are isolated from one another with as much difficulty as those in the abdominal ganglia of the skate ; and hence the probability that many at least of the unipolar and apolar cells which are seen in them, belong to the bipolar variety in reality. On the other hand that apolar and unipolar ganglion -corpuscles really exist, and that too in considerable numbers, in the gan- glia of the higher animals, and also in those of the invertebrata, seems to be shown by numerous observations on the smaller gan- glia, where no preparation is required, and where, consequently, the above source of fallacy cannot intervene. In the sympathetic cord of the frog, according to Valentin *, groups of ganglionic vesicles may be observed, without a single nerve-fibre connected with them ; Ludwig \ has also observed in the au- ricle of the frog’s heart small ganglia in which there were eleven ganglionic corpuscles, and only four or five nerve-tubes ; in a nerve passing to the bladder of the frog, and con- sisting of only two nerve-fibres, Valentin counted as many as seven ganglionic cor- puscles, \ while another, consisting also of only one or two nerve-fibres, was surrounded by twenty-four ganglionic corpuscles. In accordance with the view adopted by Wagner, that all the ganglionic corpuscles are bipolar, the nerve-tube connected with either extremity of the cell running in opposite directions, one towards the centre, the other peripherically, Robin believes that all nerve- tubes arise exclusively from the brain and spinal cord ; neither the spinal ganglia nor those of the sympathetic give origin to nerve- tubes ; the ganglion-cells are merely organs developed upon the nerve-tubes, between their central and peripherical termination, and several such may be present on a single nerve- fibre during its course. From what has been already stated, however, it seems probable that unipolar as well as bipolar cells exist in the ganglia, and consequently that nerve- tubes do originate in them. That nerve-fibres arise in the ganglia, is further shown by the accurate measurements of Volkmann and Bidder of the nerves passing to and those leaving the ganglia. The ciliary, Gasserian, and spinal ganglia in the frog were found by them to give oft' a far greater number of fine nerve- * Lehrbuch der Physiologie; Braunschweig, 1848 ; band ii. p. 602. t Muller’s Archiv. 1848, p. 142. X Ibid. 442 SYMPATHETIC NERVE fibres on the one side than they received on the opposite side. So also in the septum between the auricles of the frog’s heart Bidder has seen small ganglia, which gave off on the one side eight nerve-fibres more than they received on the otlier side. The obser- vations of Bidder and Volkmann have been confirmed also by Kdlliker. Engel*, moreover, describes a peri|)heral ganglion, to which no nerve-fibres passed, while a number of filires left it; an observation which, if correct, places beyond a doubt the question as to the origin of nerve-fibres in the ganglia. The ganglion in question he describes as being pear-shaped, and about 0'096 of a line in diameter ; it oc- curred in the perichondrium of the tracheal cartilage, and consisted of fourteen ganglionic corpuscles, with seven efferent nerve-fibres, each measuring about 0'0012 of a line in diameter. Even in regard to the bipolar gan- glionic corpuscles, it does not appear to be at all certain that they are all merely organs deve- 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 Kdlliker, has Fig. 291. spbial ganglion of a Fish. {After Bidder.') seen in the ciliary ganglion of Trigla, a bi- polar cell, both nerve-fibres of which were directed peri[)herically. 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 Zeitsclirift der Wien. Aerzte, iv. p. 307., as quoted in Kblliker’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 : thelarger 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 0 093 to 0T30 mm. in diameter, are spherical, and often flat at both poles; the smaller measures 0’080 to 0'115 mm. in length, and O'OaO to 0’070 mm. in breadth, and are commonly oval. ,ln 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 -)■ also agrees with Robin in separating the ganglionic corpuscles into two groups. In the pike the one set measure 0'042'", while the other set do not measure more than 0’018"': 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 Kdlliker, 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 Kdlliker, 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 * Aiinales des Sciences Naturelles, tom. septifeme, 1847, p. 282. ; also Canslatt’s Jahresbericht, 1847. t See Canslatt’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 ol 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 ran 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 Eemak in the Jlonatsbericht der Konigl. Preuss. Akademie der Wissenschaften zu Berlin fur Januar., 1854, translated also in the Edinburgh Monthly filedical 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 tlie 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, how'ever, in an examination of the Torpedo marmorata find such connections. On Connection between ike Sympathetic and Cerebrospinal 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 ivide 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 sheatb, form nerve-tubes with dark borders, wdiich 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 restifoime 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 motoiy 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 outer 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-cel's, 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 towmrds the cephalic and caudal extremities of the spinal cord. In the spinal ganglia the multipolar cells dis- covered by Eemak 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 Chimasra 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, w’hich 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 twe 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 com-se 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. toniists, the sympathetic was described as a continuation of the fifth and sixth cranial membrane. The number of processes varies between three and twelve; by speedily brandling 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 dilfer 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 Kemak, 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 s;ich, 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 sympathieus s. revehens) is, according to his observatious, gray, contains very fine (the fibres of Bidder and Volkmann) nerve-fibres, and very m.any 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 Wtitzer, &c., may be followed to both roots of the spinal nerves. Kemak has as j'et 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 siunal fibres with which they arc connected by means of nerves, reinforced by fibres sent to it from the differcnt-cerebro spinal nerves along its the multipolar ganglion-cells. There are no grounds for the assumption that (human) sj'inpathetic fibres exist which do not stand in connection with spinal fibres, and consequently not in connection with the great central organs of the nervous S3'stem. So also in the nerves passing off’ from the sj'mpathetic 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 s_ympathetic ganglia the angles ot 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 Lej’dig in the angles of branching of sensory fibres in CarinariaMediterranea. In the angles of branching of motor fibres gan- glion-cells are onlj' 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 servos 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 trvo 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 Gasserian ganglion of Chima;ra 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 foimd 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 sj'mpathetic motory ; through the mediinn 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 motoi-y upon the sj'mpathetic ganglion- cells and their motor processes. Besides the sj'm- pathetic sensory and sympathetic motory fibres, the assumption of a third set of sj'mpathetic fibres, serving immediately for nutrition, is not required by anj- fact in phj’siology, since it is possible to ex- phiin the. dependence of nutrition upon the nerves by the action of the latter upon the contractile walls of the blood-vessels. SYMPATHETIC NERVE. 445 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 p'resent 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 Vari entrap and Muller 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 b}' 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 Muller 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. Volkinann and Bidder, though agreeing with Valentin m regard to the fibres of Remak, still main- tained the opinion, that the 7'ami commuiii- contes 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 ties Sympathisclien Nervensys- tems von Bidder und V^olkmann, p. 29. t Ibid. J 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 diviiles 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. V. hen 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 periphericallv. In the fish and bird tliey 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, ai)proaching in this respect the appearance of the sympa- thetic nerves. Sometimes the white cord [)resents 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 cmnmunicuting filamvnt hehveen the sym- pathetic, and one of the lumbar nerves in the Cut, treated with acetic acid, showing fine nerve-fihres, and nucleated fibres of Remah. (^Mag. 250 diam.) bouring vessels, and are reduced in size before reaching the spinal nerves. Moreover, Kdl- 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 ffom the latter ; to the cerebro-spinal nerves. On tracing J the white portion of the rami communicatites 'i 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 1 corresponding spinal nerve, along with its | communicating branch, is dissected out, and I 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 inwai'ds 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 betvveen 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. n c, communicatin g branch ; c p, intercostal nerve ; c, its central extremity ; p, its peripheral extremity. Most of the fibres of the comiminicating 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 Wiitzer, Muller, 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 j", holding the view that this nerve is entirely composed of such fibres, believed that on joining the * Nerven-Physiologie in Wagner’s Ilandworter- buch, Eilfle Liefernng, p. 609. t De Functionibus Nervorum, § 152. 155. See also Quain’s Anatomjy by Sharpey. 448 SYMPATHETIC NERVE. main or gangliatcd cord they all run in a downward direction towards the pelvic ex- Fig. 294. Fibres from the root of intercostal nerve of a Rabbi t. Towards c (in the nerve chiefly con- sisted of fibres similar to (hose indicated by b ; towards b it consisted chiefly of broad fibres, A- ; o 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 tlie lex 2>ro- 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 comraunicantes, 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. Tliis view is opposed by Bidder and Volkinann*, 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 |3oint of junction with the sym- pathetic, they find that in so far as it consists of cerebro-s|)inal 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 Kdlliker, 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. Penpherical 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 diff'erent branches. In the whiter branches of the sympathetic, such as the s[jlanchnic 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 Selbstanclegkcit, &c., p. 31. . SYMPATHETIC NERVE. U9 in bundles containing from six to three nerve- rami intestinales present much the same cha- tubes forming a widely-meshed network. The racters as the nerves of the heart. Many of Fig. 295. HP, s}-mpathetic nerve ; H, ''cephalic side of the same; r, pelvic, cp, spinal nerve; c, its central, and p its peripheral end. a, portion of communicating branch running centrally; b, portion of ditto running pheriplierically ; c and d, fibres of the ramus communicans passing ufjwards in the direction of the head, and downwards towards the pelvis ; g, g, 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 cn 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, m 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 Pfeutfer's Zeitschrift, 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 tubidar 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 Ludwig on tlie neiwes of the kidney ; also by Fig. 296. Fourth thoracic rjangTion of Rahhit ; showing the course of the fibres cojitained 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 ; b, ditto passing towards the head. (^Magnified 70 diameters.') Pappenheiin on the nerves distributed to the SLijira-renal capsules. Schafliier* has also ob- served ganglionic corpuscles from which nerve-tubes jtroceeded, in the substance of the lymphatic glands. Small ganglia have also been described by Remak as occurring on tlie nerves distributed to the bronchi : they have also been observed by Kdlliker. The latter observer believes that he has seen nerve-tuhes 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 Henle und Pfeufter’s Zeitsclirift, band vii. p. 177. t IMuller’s Ai'cbiv. 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 [)ia 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, anil 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. Tiiey 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 Pappenheiin. 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 Pappenheiin) vessels pass to ligaments or tendons, nerves pass also. Development. — In the cow’s embryo of 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, presentiiig 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 ])laced 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, Bi.s- chofF found the gangliated chain distinctly formed, not only in the thoracic, but also in * Comptes rendus, 1845, p. 56G. f Luschka, die SStructur des Serosen Haute des Menscheii, quoted in Canslatt’s Jahresberidit. J Mulier’s Archiv. 1843. § Disser. Syst. Ilistor. F ormationis ac Evolution! Nervi Synipatliici : Munich, 1835; quoted in Bishoff’s Entwikelung und geschichte, French Translation. SYMPATHETIC NERVE. 451 the cervical region : the superior cervical ganglion presented the aspect of a small round nodule. In the cow’s embryo, measuring Fig. 297. Sixth thoracic ganglion of the left side, from the sym- pathetic of a Rabbit, treated with soda, and magni- fed forty diameters. Tr, main cord of sjunpathetic ; Ec, Rc, commu- nicating branches, each dividing into two portions ; Spl, splanchnic nerve ; S, small nerve proceeding probably to the blood-vessel ; G, ganglion-cells and fibres, passing into the main cord of the sympathe- tic. After Kb Hiker.') about 11 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 -HJjth of an inch in its longest diameter, soft and breaking down 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 -gtyth 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 Jg-th 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 vertebi'Ee, and concealed by the spinal cord. They presented an oblong or oval shape, mea- sured about T.jth of an inch in length and about gJg-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 Jrth 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 com.municating 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, how'ever, 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 slia[)e, about ^^tb of an incli in length and jyh of an inch in thickness, and still has the appearance of being prolonged downwards into the first thoracic ganglion. The thoracic ganglia are nuicli smaller, measuring about ^th of an inch ; and are more or less triangular iu shape, present- ing the lobulated aspect above described. The connecting cord between the diS'erent ganglia has a reddish grey colour, is flattened, mea- suring about of an inch in breadth, and presents the aj>pearance 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. Tl'.e 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 s[)lanchnic nerve, which is about 5th of a line in thickness, has a w hiter aspect than the main cord of the sympathetic. The nerves on the surlace 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 in 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 mule, 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 bumani firbrica, usu, et prorbis, 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 submaxillary ganglia formed ; and about the 6th month, the s[)heno-palatine ganglion appears ; and in the 5th month, ac- cording to the same author, the communi- cating branches between the sympathetic and cerehro-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 pn imperfect semi-lunar ganglion. In the foetus, at the full period, the superior cervical ganglion, according to Lobstein, mea- sures about 8i lines in length, and furnishes four filaments to the branches of the external carotid, while a fifth is lost on the crico- thyroitl 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. Fig. 298. , „ A 0 0 0 ® © ■ ® ^ ® ffii ® 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, 14 inch in length, consists of the following elements : 1st, bodies measuring from the yJ^^th 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 2oVofh to the lyVot'"* of an inch in dia- meter : they contain a finely molecular fluid, and also a nucleus. The hitter, 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- Fig. 299. A, Ganglion-corpuscles from the Gasserian gan- glion of a calf 7 inches long; b, nerve-flhres from the brachial plexus of the same animal ; c, from the superior cervical ganglion of the sympathetic ; i>, nerve-fibres from the main cord of the sympathe- tic in the thorax. her 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-w'all inclosing, besides a nucleus, a finely-granular fluid. They are commonly round ; some are more or less egg-shaped. The nucleus in the latter is generally situated towards the wider extremity of the cel', while its narrow end is prolonged into a delicate, granular process about the -yoaMh 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 1-|- 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 Kdlliker 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 strim, 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 4oVoth to the .jjyV(j-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 3 454 SYMPATHETIC NERVE. tinctly tubular character also ; in those of the 3rd, 4th, and 7tb, the double contour is more Fig. 301. Fr07)i the Gassei-ian ganglion of the same animal as the preceding figure. a, portion of ganglion with corpuscles in situ; h, three cor]iuscles included within a single capsule; c, ganglionic corpuscles freed from their capsules ; d, uerve-tiibes connected with the ganglion. or less distinctly visible. The optic nerve con- sists of fine tubular fibres mingletl with small round or oval bodies. The nerve-fibres iii 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 |)art of the thorax, tliere were embedded amongst its fibres ganglionic corpuscles similar in their character to tliose occurring in the ganglia of the cerebro-spinal nerves. Sometimes a single corpuscle lay imbedded iu a bundle of nerve- fibres ; in otlier parts two were seen, one situated above the other ; and in some parts there were as many a.s 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 [)resent 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. j\, nerve fibres from the brachial plexus of a Calf 18 inches long. B. a, nerve-fibres from the sjnnpa- thetic cord in the thorax ; h, tlie same treated with dilute solution of soda, showing the presence of tubular nerve-fibres, t t, similar to those in the cerebro-spinal nerves. there were no tubular nerve-fibres present ; it con.sisted 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-s|)inal system in the foetus measuring 6 to 8 inche.s 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. SYMPATHETIC 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 tbe muscles of the trunk, form e.xamples 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 manj' distinct nervous centres, each presiding over the actions of the parts to which it sends nerv'e-filaments, and each discharging its func- tions without any relation to the brain or the spinal cord. The involuntar}' 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, w'here the muscles supplied by cerebro- spinal nerves are all thrown into a state of more or less violent contraction, the muscular organs w'hich 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 ()arts 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 perfectlj', 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 ilistinct 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-s[)inal 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 wdth the rhythmical movements of the muscles of respiration. Again, there are organs which are supplied by nerves of cerebro-spinal origin, and w'hich notwithstanding resemble the organs supplied G G 4 456 SYMPATHETIC NERVE. by tlie sympathetic in the circumstance that the normal impressions whicli are made upon them do not reach the sensorium. Thus, the greater part of tlie mucous membrane which lines the bronchial tubes, as well as that of the cesophagus, I’eceives 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 sup[)lied, 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 tlie blood and 1\ in|)hatic 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 peculiaidty 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 sujjra-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 de])endent on the sym- pathetic is shown by the circumstance of few or no sympathetic fibres being sent to the extre- mities. Tlie 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 ajiplied to the spinal cord being capable of exciting contractions in the heart and intestinal canal, while on the other hand stimuli apjilied to the latter may also be ti'ans- mitted to the former. This is shown by the severe pain which is felt in organs stipplied by the sympathetic, when affected with disease, as well as by the circumstance that irritations of the intestinal canal not tin frequently 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 conveyed along the centripetal nerves to the spinal cord, and are there trans- ferred to the motor nerves wdiich pass to the voluntary muscles, exciting them to contrac- tions. As already stated, Y'alentin believes that all the true nerve-fibres which are pre- ftent 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 cei'ebro-spinal nerves. The sympathetic is therefore, according to him, a cerebi'o-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 numl)er 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 tlie 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 ott' in different directions ; some to the viscera, others to the extremities, along with the cerebro spinal nerves, and by means of which the nutritive jtrocesses are regulated. Thus, while the internal viscera receive sen- sory and motor nerve fibres from the brain and sjtinal 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 Remak-|-, R. Hall;!;, 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 tho.se 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 inwartls to the viscera, over whose movements and nutrition they preside, while others pass along with the eerebro- 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 Pliysiologie de Syst&me Nerveux, tome ii. p. 5G9. et seq. f Observat. Aiiat. et IMicroscop. de Systemat. f Nerv. Structura, Berlin, 1838. ■; J Edinburgh Medical and Surgical Journal, July, 1846, &c. § Wagner’s Handworterbuch der Physlologie Zelinte 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 tei'metl 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 circidation, 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 w'ay 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- five 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 coidd 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 tvere filled with coloured mucus ; such was observed to be the case even in animals whose sjfinal 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 obsei'ved 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, sore.s 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 wdth 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, hut 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 w'hich 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, fiEces, 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 Volkraann, 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 reffex 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 princi|ffe associates the muscular movements for the attainment of an organic object or purpose ; in the others this does not take place. When the re,gular 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 (juiverings 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 s[)inal 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 colla[)sed 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. Hailer 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 Dupny, k See Longet. op. cit. tom. ii. SYMPATHETIC NERVE. 4.59 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 ; alter- 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 || gives the followdng 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 similarl}’ 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. etles Ponc- tions du System. Nerv. p. 229., as quoted by Longet. t Rech. Experiment, sur les Fonct. du Systbme Nerv. Gaugl. 2nd edit, Paris, 1837, p. 357., as quoted by Longet. I Op. cit. ii. p. 56G. § Lehrbuch der Physiologie des Menschen, 1844, band ii. p. 421. II 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 mu.st 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 •pro'perties. — That the sy'inpathetic 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 Kurschner.f Mechanical or chemical irritation, but especially galvanic * Op. cit. p. 3G0., as qnoteci by' Longet. t Abbandlungen tiber das Nerven System, von M. Hall. Aus dem Eiiglisclien von D. C. Kursh- ner, IMarbm'g, 1840, Nachtraege, p. 182. 460 SYMPATHETIC NERVE. stimulus applied to the filaments of the sym- pathetic which pass to the lieart, 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 tlie sympathetic, especially in the intestines, spontaneously, at least under the stimidus of the atmosjthci'ic 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 ex[)criments 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 [tneumogasti'ic. 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 i 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 aoi'ta at the dis- tance of ith of a millimetre from the heart, or upon the surface of the right ventricle, no effect was [troduced. He concludes, therefore, that the .stimulus when ajtplied to the nerves was, in this case, more effectual than when ap|)lied to the muscular fibres themselves. As regards the function of those filaments which are sent by the pueumogastric to the heart, E. H. Weber -f- believes that they exercise a re- * Loc. cit. p. 427. t AVagner’s Handworterbuch der Pliysiologie, band iii., Abtbeilung ii. p. 45. straining influence over the movements of the organ ; stimulus applied to the pueumogastric, according to his experiments, having the effect of retarding or altogether stopping its move- ments. When the stimulus of the electro- magnetic rotation a|)paratus 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 pueumogastric 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 heart, a cessation of its movements is again produced. The circumstance that the heart, after the stimulus has been applied to the pueumogastric 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- erci.sed 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 pueumogastric. 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, among.st other branches, a slender filament which is destined for tlie 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. Schiflf 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 cert.ain 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 wdiich 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 speedily fatal. Haller J, 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. t Cerebr. Auatomia Nervorumque Descript, et Usus, p. 195. t Dissertat. siw I’lrritabilite, 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 tlie 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*, Budgef, Valentin t, 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 Handworterbuch, band iii., 2nd Abtheil, p. 44. •f Ibid. p. 415. &c. j Lebrbuch der Physiologie, 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 quadrigeniina were the I)arts to w'hich 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 w’ires 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 vertehrte. After repeating this ex- periment several times, and with the same result, he cut the spinal cord across in the I'egion of the second to the third vertebra ; when the stimulus was now a[)[)lied 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 tw'o lowmr 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, vvere now apfilied to the upper part of the spinal cord, in the region of the fir.st cervical vertebra, the heart, which was before at rest, commenced pulsating. The spinal cord w’as 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 ujion application of the wires, because the roots of the nerves were stimulated. When the heart was cut out of the bodj', and again placed in situ, the above experiment was repeated without effect. .lust 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 sjfinal 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 region 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 siiles, 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 bj’ 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- I 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 i stopping its action also illustrate the same ■ thing. j 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- liaritiesin the manner in which they are acted upon by the blood, the contact of arterial with 1 the lining membrane of the left cavities of the organ, that of venous blood with the lini.ig / membrane of those of the opposite side, fur- j nishing the proper stimuli, in obedience to i v/hich 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 :J also, while the contraction of the ventricles i causes the auricles to become again filled with blood from the veins, and so on indefinitely. This rhythmiea! 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 j it is composed, as may be seen on examin- I 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 aredescribed as passing between 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. Tliese 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, how'ever, 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 movem.ents 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. 616. &c. 46i 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 remler 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 hotly, 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 [irobable by several circumstances, but especially by the observation first made by Henry, and after- wards by Midler*, that solution of opium or of other narcotic substances, when applied to the outer surface of the heart, does not pi'oduce 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 ap|ilied 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 ap|)lied 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 tlirection to the different muscular parts of which the heart is composed ; and this can only be supposed to be effected through the metlium 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. If, 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 seej. 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 incisioiis 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 i,s 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 exerci.sed 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. Inieathial canal. QHsoiihagiis. — 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 c;so- phagiis ; 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. 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 s|)lanchnic 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. Volkmannf 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 Midler, by application of chemical irritants, such as potash, to the solar plexus. According to V^alentin, 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, ami 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 prodrtced in the particular por- tions of the intestine to which they are dis- * Op. cit. p. 609. + Muller’s Archiv. 1845, p. 414., &c. 465 tributed, while the rest of the gut remains quite motionless. Budge observed that move.ments 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 proiluced 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 Ct/prinus tinea, Weber has shown that very 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 ex[)eriments 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 proiluced 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 a|ipai atus 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 hrain and spinal cord have been destroyed. Bidder, as * Op. cit. p. 466., &c. 4C6 SYMPATHETIC NERVE. cited by Volkniann, fed several frogs with worms and immediately destroyed the spinal cord : on opening the animal twenty-four hours afterwards, the stomach was found distended vvitli lough slimy matters : if, on the other hand, forty-eight hours were al- loweil 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 de[)end. The contractions which take place may be ex[)lained 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, howevei’, that they are re- gulated by the ganglia of the sympathetic, especially since it has been observed by Henle*, that in [lieces of the intestine which have been cutaway close to the line of attach- ment of the mesentery, the contractions [iro- duced by application of local stimuli extend but a little way on either side of the point irritated, and are comparatively feeble. When a [lart 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 frecpiently 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 bkulder contractions .ire more easily pro- duced than in the ureters: sometimes shortly after ofiening 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- jilied to the sym|)athetic 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 apiilied to the two last lum- bar ganglia: the rabbit and guinea-pig were the animals on which this experiment wms made. In the latter animal the vesiculre seminales were also excitetl to contraction by irritation aj>j)lied to the lower lumbar and njiper sacral * Allgcmeine An.itomic, p. 724. t Op. cit. p. 4U8. 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 inlluence 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 sitle 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 spinal 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. J Molinelli regarded the effect pro- duced upon the pupil not as an immediate effect of the operation, but as an after result; * Bulettin de I’Academie de Medicine, tom. ix, p. 1124. j- Histoire de I'Acadeinie, 1727, 1729, Paris, p. 5. et seq. X See Budge, in Viorordt’s Archiv. fiir physio- logische Heilkunde, 1862, Ergiinzungs Heft. SYMPATHETIC NERVE. 467 by Dupuy, on the other hand, it was de- scribed as tlie immediate consequence of the same. Reid found in his experiments that tlie 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 piqal 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 pu])il has generally a circular form ; there are, however, occa- sionally seen particular inequalities in its margin which change from lime 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. Bifff 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 pu|)il; 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 syni])a- tlietic, 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 pliysio- logische Heilkunde, 1852, Erganzimgs 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. They might be supposed to arise in the inferior cervical ganglion, or to be derived from the spinal cord through the medium of the rami comraunicantes. 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, ditl 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 ot the spinal cord which has most influence on the pu[)il being that in the region of the first three thoracic vertebrce. 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 l)v 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 impression^ which are transmitted to the sensorium, must, Volk- mann observes, raise a suspicion that tlie very rich network of nerve-fibres which occurs in them are not posses.sed of sensory properties, and the results derived from experiments, as * Loc. cit. p. 601. 11 H 2 4C8 SYMPATHETIC NERVE. well as from surgical operations, would seem to show that such is the case. The coats of the blood-vessels he consiilersto 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. iind. 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 filjres 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, however, api)ear to take [dace. 3rd. It is not at all probable that fibres, which in ani- mals that have been beheatled, or are under the influence of strychnine, show so little connection with the spinal cord that] stimulus applied to them cannot excite any refle.x 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 inconsiderablcquantity 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 sym[)athetic, 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 cerebi'o-spinal fibres distributed to such parts is too small to explain it. Severe pain is frequently felt in bones when diseased, although, accoriling 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 [)ossessed of motor properties. They hold the relation of centripetal or afferent fibres to the ganglia of the syiiqiathetic. 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 synqiathetic 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 symita- 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 s|)inal 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*, Longctf* and others, they are denied this property. * Op. cit. p. 697., as quoted by Longet. t Op. dt. p. 678. 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 of sensory nerves, and are there transferred to motor nerve-fibres. Grainger -f-, 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 jl, 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 was 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. Longet^ 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. t Observations on the Structiue and Functions of the Spinal Cord. t Mhller’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 piobable. Kiirschner also adopts the view that the gan- glia are to be regarded as centres of refle.x action. On repeating Muller’s experiment of irritating the solar ganglion wdth potash, he observed that the movements thereby pro- duced in the intestines did not comn)ence at a single point, but in several different coils of the intestine at one and the same time. This mays 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 w’hich 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 Neue Notizen, band xii. p. 247., a* quoted by Kiirschner. H H 3 470 SYMPATHETIC NERVE. tliat no reflex action could be produced in the voluntary muscles. The heart was then laid bare, and during an interval oflOl 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 31 per minute. He then crushed with the blow of a hammer one of the hind feet ; and now, during the 104 th minute after the spinal cord hacl been de- stroyed, counted 70 pulsations. Tims, 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 symi^nthelic 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 exercisetl, while others hold that it exercises no influence in this respect which is not also exercised by the cerebro-spiual system. There can be no doubt that in the plant the processes of nutrition take [)lace without the co-operation of any nervous influence; and in the same wav 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 vnay 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 Drs. 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 upon 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 w'ound 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 ilivihion 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 tliat 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. I De vi motoriabasios encephali, p. 37., as quoted by Valentin. SYMPATHETIC NERVE. 471 while lane of no differentiation being directed inwards. If, for instance, we compare the young skin of a mammal wdth 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 3J 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- jjosed 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 c, on the other hand, is the dermic area of metamorphosis, the indifferent tissue gradually changing into connective tissue. It w’ill be observed here, that as the whole serous layer of the germ corresponds in struc- ture with the epidermis onlyy of the fully formed animal, so the wdiole integument of the Flydra 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 Flydroid 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- t^media’’ divides into its parietal and intes- tinal laminae. 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 Hydras, one contained within the other. Both the intestinal parietes, and those of the body, pre- sent the same distinction into a central 2)lane of no differentiation, from which growth and metamorphosis proceed inward and outw’ard 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 w hich 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, wdience 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, ivith its external and internal arece of nietamoiphosis collectively ; these being simply the exjoressions of two j)ro- 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 w’hich it can be properly enunciated. The term “Epidermis,” for instance, at |)resent, 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 with the derma. Nor have w'e any word for the boundary line be- tween the endogenous and exogenous are® 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 tw’o 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 growtli and metamorphosis, I term the FrotomorjMc line. The whole ex- ternal (free) area of metamorphosis I call the Ecderun ; the entire internal (deep) area of metamorphosis, the Enderon. It will he observed that tliese definitions rest wholly upon the mode of groivlh, 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 tliat mere structure affords no base for homology ; the eederon, for instance, presenting every variety from tlie structurelessness of a homo- geneous membrane, as in the Tmniadae, to the complex combination of the so-called enatnel, 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 |)lants 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 [leriosteal area of metamor|ihosis ; 3th, 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 camhial) 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 metamorphic area of the endophloeum or liber; within which is, 3th, the pi'oto- 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 (y?g.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 eederon and enderon in the animal ; a', inner protomorphic line between liber and wood of plant, between bone and periosteum of animal ; 6, b', cork and epidermic layers of plant ; cellular epidermis and scale of animal, fish,c.g. ; c, mesophloeum, enderon (derma) ; d, liber, periosteum ; e, e', wood and pith, bone and cartilage ; .r, axis; ?/, surface. The consideration of vegetable structures will aid us even further in understanding the manner in which the different varieties of in- tegumentary organs, with which we shall meet, are formed. For it is well known that the outer covering of a plant may ultimately be constituted in one of three ways. 1. The original cellular eederon may persist un- changed. 2. The “epiderm” persisting, a la- minated, but otherwise structureless “ cuticulaf may be developed ujion its outer surface, attaining sometimes a very considerable thick- ness. 3. The original ejiidermis is cast off, its place being taken by the development of a new layer of different, usually suberous con- stitution, beneath it, which then goes on growing endogenously, and constitutes the pennanent integumentary surface. Now, we find a precise [tarallel for all these conditions in animals. In the soft integument of most Mollusca and Vertebrata the first condition obtains, the general surface of the integument being constituted by the cellular “epidermis.” In the Annulosa, on the other hand, the integument has certainly, in many cases, and [ think probably in the great majority, the cha- racter of a vegetable cuticle, consisting as it does of layers developed from the outer sur- face of the cellular eederon. In this way also I believe that all molluscan shells are formed. Lastly, the fish-scale produced altogether beneath the cellular ecileron or epidermis, but growing endogenously after the manner of a true ecderonic structure, appears to he precisely analogous to the corky periderma of the plant ; and as the latter, though it is not the original epidermis, takes its place and grows in the same way, so in the fish the scale, which is assuredly not a calcification of the cellular eederon, yet represents it both in position and in mode of growth. ^ 2. Morphology of the integuments, — In the 11 ■•J TEGUMENTARY ORGANS. 477 embrvonic state of all animals, and in the adult condition of many of the lower forms, the in- tegument, constituted as above defined, forms a continuous investment over the surface of the body without any important processes or irregularities. Such is the case in many of the Worms, Polypes, and lower Mollusca. From such simple forms of integument as these the most rudimentary kinds of appendages or tegumentary organs are produced in one of two ways, — either the outer portion of the ecderon is thickened, and as a spine or as a plate projects beyond the common surface — e. g. cells of Hydroid and Polyzoic Polypes ; or the whole integument is developed into a spine-like or plate-shaped process, as in the so-called “bracts” of the DijihydEe, and in all the spines, hairs, and scales of the Insecta, Crustacea, and Arachnida. The shells and plates of Mollusca and Arti- culata belong principally to the former division, being simple laminated thickenings of the outer portion of the ecderon. In the Vertebrata the integument but rarely possesses appen- dages of so simple a nature. Simple plates of this kind, however, coat the surface of the beaver’s tail, in which animal, according to Heusinger, “ the epidermis is divided by a great number of clefts into hexagonal por- tions 4 lines long, whose whole edges ad- here to the cutis. They usually consist of a couple of superimposed laminse identical in structure with the rest of the epidermis ” (?. c. p. 168.). The polygonal horny plates of the Chelonia are of the same nature. The scales on the under surface of the tail of the rat and other rodents, and on the tarsi of birds, are similarly constituted ; but here one edge is thrown up, and we have a transition to the scales of the Pangolin, — to those of Ophidia and Sauria, — and to the nails, claws, hoofs, and hollow horns of Mammals, and the horny sheaths of the beak of Birds, all of which are constructed on essentially the same plan, being diverticula of the whole integument, the outer layer of whose ecderon has undergone horny metamorphosis. Among these the nails, horns, and hoofs of mammalia present certain complexities of arrangement which entitle them to particular notice. TVai/s are flattened horny plates developed from the upper surface of the jrhalangeal in- tegument only ; they are free at their distal extremities, but laterally and at their proximal ends they are enclosed within raised ridges of the whole integuments, the nail walls. The enderon beneath them in the space which is called the “ bed of the nail ” is raised into parallel longitudinal ridges or laminre, which fit into corresponding depressions of the under surface of the ecderon. Claws are nails which embrace a larger portion of the phalanx, being developed, not merely from its upper surface, but also from its extremity, and extending far round on its sides. In the dog and cat (j?g.305. a) the bed of the claw is laminated as in man, but pre- sents no papilltE (Gurlt), and a bony plate extends from the last phalanx into the pos- terior fold of the nail. The transition from the claw to the hoof\s readily understood if we suppose the terminal portion of the former to be blunt and cylindri- cal, instead of pointed and conical {Jig. 305.). The elephant and rhinoceros do in fact afford an actual passage from the nail to the hoof, inasmuch as their very flat nails are con- tinuous at their edges with the solid horny covering of the sole (Heusinger). The solipede hoof has been described in the article Solipedia; w-e need therefore only remark here that the luall corresponds with the nail in man, and may, by maceration, be separated from the sole and frog, which are developed from the termination and pos- terior surface of the phalanx. The ridge or “ bourrelet ” at the upper margin of the wall an- swers to the posterior nail-wall, and, as in the nail, the horny upper layer of the “epidermis ” is continued on to the hoof from it. The struc- ture of the bed of the hoof differs in its different parts. That portion wdiich corresponds with the sole and frog merely presents papillae, which fit into depressions of the horny ecde- ron ; that w’hich corresponds with the wall is produced into lamellae like those of the bed of the nail, so that the deep surface of the wall is laminated. In addition, however, long papillae extend from the “ bourrelet ” through the superficial portion of the wall, so that, on section, it presents a superficial series of canals, around which the horny matter is disposed in concentric layers. Fig. 303. A. Section of the foot in a kitten, b. In a fcetal Iamb. Each half of the hoof of a ruminant (Jg. 305. b), or of the pig, corresponds in general struc- ture with the entire hoof of a solipede, except 478 TEGUMENTARY ORGANS. that the frog is rudimentary. The horny ecderon presents botli tubuli and lainiiiEe. The excrescences on the inner surface of the leg of the horse are identical with the sole of the foot in structure — consisting of a horny mass penetrated by long papilla;. The hollow horns of the Ruminantia are, to all intents and purposes, Claws. The super- ficial cellular ecderon (epidermis) is continued upon them, and, when this is removed, we come to a laminated fibrous horny mass, which is formed and increased by apposition from the subjacent process of the enderon, supported by its bony axis — a process of the frontal bone. The enderon has neither villi nor lamellae, presenting only small irregular ridges ((Rirlt). The hui'n of the rhinoceros is commonly said to be constituted by a mass of hairs wdiich have coalesced. However, it consists of an aggregation of tubes, round which the horny matter is arranged in concentric lamina;, as in the horny excrescence of the horse’s leg ; and as there is no evidence of its having ever been enclosed within a sac, it is more probable that it belongs to the series of the claws anil nails. Glands, hairs, and feathers. — The Hairs and Spines of mammals, the of birds, and the Integumentary Glands agree in one essential point, that their development is preceded by that of an involution of the ecderon, within which they are formed, and by which the former are, at first, entirely en- closed. At an early period, the rudiments of the hairs, and those of the cutaneous glands of a foetal mammal, are indistinguishable. Tiiey alike consist of solid [irocesses of the ecderon, consisting of a homogeneous matrix, in which lie closely-set endoplasts, bounded internally by a clear, narrow, transparent “ basement membrane,” which at once sepa- rates them from, and connects them with, the enderon.* Externally these processes are con- tinuous with the rote mucosum of the ecderon. In the fcetal lamb, in which I have carefully traced the development of these processes, they increase in size without change of struc- ture, until, in the ordinary hairs, they have attained a length of inch ; for the vi- brisste, that of inch. Having reached this length, it is seen that an accumulation of the indifferent tissue of the enderon has taken place around their coecal ends, which gradually become pushed in, so that, from being rounded, they ajjpear truncated in section, and present a bulb with a hemisphe- rical involution, the rudiment of the papilla. In the ordinary hair no special accumulation of indifferent tissue takes place around the body of the involution; but in the vibrisste, which are ultimately to possess a thick outer capsule, its foundation appears in this form, and a capillary loop may be seen penetrating the rudimentary jiapilla. In the furthest advanced vibrissas the * The further development of the glands will be most conveniently considered, together with their histological structure, below. tissue of the axis of the sac was converted into horny cells, the rudiment of the “ fenes- trated ” or of the inner, horny rootsheath. Over the papilla the rudiment of the hair shaft was indicated by a conical process, horny at its apex and marked by radiating lines. Finally, on each side of the neck of the sac there was a bulging process, the centre of wdiich was occupied by a mass of fatty-looking granules, the future sebaceous glands of the hair. Hairs are not normally susceptible of inde- finite growth, but have, like the teeth, a fixed form to attain. This form is always that of a more or less elongated spindle, inasmuch as the hairs are sharp at their points, becoming broader and thicker in the middle, and dimi- nishing again to their proximal ends. When fully formed, and ready to fall out, in fact, this end of the hair is either pointed, or more or less ragged and brush-like. As soon as the finishing process of any hair begins the foundation of a new one is laid by the development of a diverticulum of the outer rootsheath towards its base, in which a young hair is developed, in the man- ner already described, and gradually pushes out the old one. The varieties of form and appearance pre- sented by the hairs of animals (for which see the works of Hensinger, Eble, Busk, and Quekett, cited at the end of this article) are produced ; 1st, by the relative proportions of the medullary and cortical substances, and the arrangement of the former with respect to the latter. Thus the [)eculiar appearance of Rodent hairs is due to the disposition of the medullary substance. 2nd, by the deve- lopment of the cuticular layer, whence arise the whorled scales of bat’s hair — the imhri- cated plates of seal’s hair, &c. ; 3rd, by the sha|)e of the shaft, which may be cylindrical, as in ordinary hair of the head in man ; or evenly flattened, as in the short curly hairs ; or narrow and cylindrical below, and wide and flattened above, as in the hairs of the deer tribe. The spines of certain mammals, such as Hystrix and Erinaceus, present some inter- esting peculiarities of form ; offering, as they do, a sort of transition between hairs aiui feathers.* The porcupine’s “ quill,” as it is called, is a cylindrical tube which gradually diminishes to a point above and below. At its apex the cavity of the quill is simply conical, but low'er down its section becomes polygonal, and, the angles of the polygon being prolonged, resem- bles a four-rayed star. Still further tow'ards the root of the quill, each ray of the star divides into two secondary rays, and then the secondary rays subdivide into two tertiary rays ; so that eventually the cavity of the spine is a complicated star with four and twenty branches. Below its middle, the quill dimi- nishes in diameter, and at the same time the complexity of its internal cavity likewise dis- * See Brocker (Eeicliert’s Bericht, 1849), fi'cni whom the account iu the text is taken, though the main points liave been independently verified. appears, the tertiary rays disappearing first, and then the secondary, &c., until at last the cavity is circular as at the apex.^ The boun- dary of the quill cavity is immediately formed by medullary substance ; but the cortical sub- stance follows to a certain extent the con- tour of the inner cavity, so that in a transverse section of the middle of the quill the cortical substance presents the same general outline as the medullary, though its processes and insec- tions are less marked. In the adult condition, the central cavity is filled by an irregular horny mass, \vhich Reichert and Brdcker regard as the dried-up pulp, but which is probably, as in the feather (vide infra), simply the last horny product of the pulp, filling up the space which the latter once occupied ; for it is certain that every por- tion of the porcupine quill has, like every por- tion of a feather, at one time constituted a cap over the corresponding portion of its pulp. The pulp, in fact, commences like that of a feather, as a smooth conical process upon which the apex of the quill is moulded. As it grows, however, the pulp assumes an angular form, and then, as that of a feather would do, becomes produced into lamellae. By the constant production of new elements at the surface of these lamellae and their cornification, the “quill” is produced, and retains internally the impression of the mould on which it was formed. Apart from the arrangement of the lamellce, the principal difference from a feather which tlie “ quill ” presents, is simply that it does not, as it is formed, split up along the lines of the lamellae of the pulp. In its main features, the process of deve- lopment of feathers is identical with that of hairs. A solid diverticulum of the ecderon is first formed, within which the primary change consists in the metamorphosis of cer- tain median cells into a cone composed of horny plates. There is thus formed, as in the hair, an outer rootsheath, resembling and con- tinuous with the rete mucosum, an inner root- sheath, and a central papilla, the so-called matrix of the feather (fig. 306.). The horny rootsheath (^g. 306. c) attains a very considerable thickness, and instead of stopping short of the mouth of the sac, as in the hair, its outer end is for a considerable time pushed forwards by its basal growth fari passu with that of the feather; so that it eventually projects for a considerable dis- tance beyond the surface. Finally, it opens and allows ofthe passage of the feather, which grows through it, the horny layer ultimately forming a true rootsheath around the quill. Like die rootsheath of the hair, this structure consists of two layers, an outer (c), denser and harder, and an inner (d), softer and more flexible. The latter from being marked by the projec- ting barbs of the young feather has been called the striated sheath. Both layers, however, have the same essential structure, being composed of rounded or polygonal horny plates, whose endoplasts are often distinctly retained even in the outer layers. The histological meta- morphosis of the feather will be described TEGUMENT ary ORGANS. 4.79 below, but the manner in which it acquires its ultimate complex general figure requires particular attention. Referring for further de- Fig. 306. Sectional view of feather in its sac : Fowl, e, barb ; /, pulp ; ff, venal. tails to the article Aves, I may state here, that every feather consists of the following parts : — the quill continuous with the shaft, or central axis of the feather, which supports the hori- zontally expanded vane, consisting of numerous long, narrow, flattened lamiiiEe ; the barbs or primary rays, pointed at their extremities and arranged with their edges u[)wards and down- wards more or less perpendicularly on the shaft. Arranged in a similar manner on the barbs, are the barbules, which therefore are disposed more or less parallel to the shaft ; from the sides of these, lastly, project short, toothed, curved, interlocking procesiw. All parts of the feather are solid, except the quill, which is hollow and occupied only by a dry shrivelled mass, the pith, in its up|)er part, while below, during life, it receives the pulp. Superiorly, on the under side, where the quill joins the shaft, there is a small aperture, which communicates with the interior, with a short canal in the shaft, and with a groove which runs along its under surface. It may be well to remember that the apex of a barbule resembles in structure one of its own processes ; that of a barb, one of its bar- bules ; that of the shaft, one of its barbs. The development of this complicated organ from its matrix or pulp takes place very simply, by a sort of exaggeration of the com- bination of hair development w ith that of the 480 TEGUMENTARY ORGANS. nails, which has already been described as occurring in the spines of the porcupine. On the surface of the leather-pulp a series of ridges are developed, running pretty nearly parallel with one another from an an- tcro-posterior groove upon the upper surface, which marks the position of the future shaft, to a line parallel with that groove upon the under surface or the process, which is called the rajihe. These ridges, therefore, bound as many grooves which branch olf from the niedio-dorsal groove, becoming gradually shal- lower, to the raphe. These secondary grooves, as they might be termed, how- ever, are not themselves simple ; their walls, the ridges, being again |n-oduced into short parallel laminae, and therefore giving rise to tertiary grooves, branching off from the secondary ones. Now, the whole surface of the matrix being covered by an ecderonic layer in process of conversion into the cor- tical and medidlary substances of the fea- ther, the (irimary groove becomes filled by the end of the shaft ; the secondary grooves by the terminal barbs, the tertiary grooves by their barbules, while the processes appear to be outgrowths from these. VV'ere all this conical horny cap to remain entire, the result would be a very complex sort of porcupine’s quill ; instead of this, however, it breaks up along the line of each ridge, and so we have a feather. The extremity of the feather being thus con- stituted, how is its remaining length developed ? According to Rcichei t, the whole pulp elon- gates, and as fast as a portion of the feather is completed, the corresponding segment of the pulp dries up, constituting for the vane what has been called the inner striated membrane {e'). However, I believe that this is not the case, the inner striated membrane being, like the outer, a mass of cornified cells detached from the surface of the pulp, just as we shall see the pith of the shaft to be, though this has been also declared by Reichert to be dried- up pulp. I believe that the growth of the feather, on the other iiand, resembles that of the hairs and nails; viz. the extremity as it is finished, is pushed up by the growth of the base, the pulp only supplying materials from its surface ; and I account for the inner stri- ated membrane by siqiposing that a compara- tively imperfect development of horny cell membranes takes place from that surface of the pulp which would otherwise be left bare, when the terminal cone or plume of the feather is pushed away. When the development of the shaft has gone on in this manner for a longer or shorter time, according to the length of the feather, a change takes ]dace. The pri- mary groove, which has gradually widened with the witlth of the shaft (to the exclusion of the secondary grooves, which gradually shorten and ultimately disappear) becoming shallower, extends all round the pnl[), and the formation of medullary feather substance ceases, that of cortical substance alone remaining. Thus is the hollow (juill formed, and its edges, not quite closing above, leave the minute um- bilical aperture by which the inner striated membrane is continued into the “ pith ”of the quill. This pith is produced by the throwing off of successive transverse horny partitions from the apex of the pulp, as the quill is pushed beyond it : thus protecting itself from the air admitted by the umbilical aperture, and which is visible, occiqjying the chambers thus formed (y?g. 3 1C. g). A full description of the various forms of feathers is given in the article Aves in a former portion of this work, to which the reader is referred. There can be no question as to the relations of the integumentary organs hitherto described to the primary constituents of the integuments, but it is different with regard to those cal- cified tegumentary appendages, the scales of Fishes, and the so called “ dermal” calcified plates of Reptilia and Mammalia. One point is quite certain with regard to these append- ages, that they are not, like the calcified shells of themollusca, the representatives of the outer portion of the originally cellular epidermis (are not therefore comparable to the “ cuticula” of a plant), inasmuch as the latter may always, in their young state, be traced over them. It is for this reason, I imagine, that they are at present ordinarily called “ dermal” organs. A truly dermal or enderonic organ, however, ought, if it continues to grow, to re- tain the same characters as the enderon of which it forms a part. It ought, therefore, to have its |)rotomorphic surface external and to grow exogenously. Now, no scale or plate of any fish, so far as I am aware, does this ; on the other hand, it holds good of all, whether Placoid, Ganoid, Cycloid or Ctenoid*, that they commence by the occurrence of acalcfiic deposit immediately beneath the cellular ecderon, and that they increase by continual addition to the inner surface of this primary deposit. There are two w'ays in which we ma}' conceive that these scales and plates are produceil. Either they are a gradual calcifi- cation of the whole enderon from without inwards (which is the view taken by Leydig, of the scales of Polypterus), in which case the only tissue of the enderon capable of increase (that of the protomorphic line) being arrested by the calcareous deposit, the whole enderen at these parts must cease to grow, whi.h would appear to be contrary to fact ; or the scale corresponds with the cork-layer of the vegetable integument, and like it, though develo|)ed beneath the ordinary cellular epi- deiTiiis, is still a truly ecderonic structure. A great deal might be said for both the.se views; and if in this place, I assume the latter to be more correct, it is because I think we must be guided by the homology of the scales with certain other organs, where these refla- tions are more definitely expressed. It may be taken as certain, I think, that the scales, plates, and s[)ines of all fishes are homologous organs; nor as less so that the tegumentary spines of the Piagiostomes are homologous with their * And I believe it will be found to be equally true of the “ dermal ” bones of reptiles and mammals. . TEGUMENTARY ORGANS. 481 teeth, and thence with the teeth of all verte- brata. Again, it appears to me indubitable that the teeth and the hairs are homologous organs ; they are therefore either both en- deronic or both ecderonic. Taking for granted the validity of a basement membrane as a mark of the boundary between ecderon and enderon, I elsewhere * arrived at the conclu- sion that the teeth are enderonic organs, and that therefore the hairs must follow them. Now, however, that a “ basement membrane ” turns out to be no test at all, there seems no reason why we should not be guided entirely by the direction of growth, and consiiler both hairs and teeth as ecderonic organs ; the former being a development of the cellular ecderon, and corresponding with the ordinary horny epidermis ; the latter, a development of a deep layer of the ecderon beneath this. It appears to me that we can do no other than admit this view for the teeth ; but if this be the case, we may apply it to the scales of fish (and the “ dermal plates ” of reptiles ?) also; as there are no difficulties about the latter which are not also presented by the teeth. There appear, in fact, to be but few ob- jections of any importance to the assump- tion of the ecderonic nature of fish scales, the principal ones being the continuation of the tissue of the ecderon over the upper surface of the scales; the apparent passage of the bony structure into the laminae of the connective tissue of the enderon below, and the vascularity of the latter. The continuity of the enderon over the scales will be seen below to be more apparent than real. I have not been able entirely to satisfy myself, as to the exact relations of the parts, in the case of the eel, but in the other fishes which I have examined the surface of the scale is very partially covered by the enderon, being in its centre, at any rate, in'contact with the cellular ecderon. The vascularity of the scale never extends to its most superficial layers, and may be ex- plained in the same way as that of the test of an Ascidian, which however is unquestionably an ecderonic structure. Thepassageof its deep layers directly into the connective bundles of the enderon, which Leydig has observed in Pol}'- pterus (and which I will not say|does not occur elsewhere, though I have not observed it), would appear to me only to indicate that this scale, and perhaps others, are composed of tvvo portions, a superficial ecderonic part e.xtend- ing as far as the most superficial vascular canals, and a deep portion beneath these be- longing to the enderon. However, all these points can only be de- cided by a much more extensive series of in- vestigations, principally directed to the ascer- tainment of the position of the protomorphic line and of the direction of growth of the constituents of every scale, than I have hither- to had time or opportunity to carry out ; and as the attention of other observers does * On the Structure and Development of the Teeth, Quarterly Journal of Micros. Science, 1852. Supp. not appear to have been directed to these par- ticular points, the question must for the present I'emain undecided. Professor Williamson in his valuable and philosophical contributions to our knowledge of this subject (Phil. Trans. 1849-1852) laid the foundation for a comprehension of the mode of development of fish-scales, by pointing out that Agassiz’s views, though essentially true, yet require a certain modifi- cation. For though a fish-scale does really grow by the apposition of layers to its deep surface, as Agassiz asserted, yet it is not in- cluded in a sac of the epidermis (if by that term we are to understand the ordinary cellular ecderon) ; and it is also true that its deeper portions grow by their superficial surface. Professor Williamson points out, in fact, that every fish-scale consists of at least two portions, a superficial homogeneous, or at most canaliculated, laminated layer, the ganoin (so called enamel or horny layer of authors), and a deeper, also laminated, fre- quently fibrous or osseous portion commonly traversed by Haversian canals. Now these two portions have a certain independence in their mode of growth, at any rate after their first formation, as may be easily understood by the accompanying diagram (y%. 307.), which represents a series of imaginary sections of scales from their first growth onwards ; a, is the protomorphic plane ; b, b", the deep ecde- ron; b', the superficial cellular ecderon, and the line X, the centre of the scales from which development commenced. Fig. 307. Suppose A to be the youngest scale, con- stituted merely by a thickening and calcifica- tion of the deep ecderon, which in b has added several layers by apposition to its inner surface, all of which retain the ganoin struc- ture except the deepest, which becomes fibrous in its texture, and forms the commencement of the “ Lepidine” layers of the scale ; — these layers, however, being as much a part of the ecderon as the former. In c the scale widen- ing, the edges of its “ Lepidine ” layer do not remain in contact with the ganoin layer; but it will be obvious that the re-entering angle thus formed by the protomorphic line between the two, is only, as it were, a fold of the deep surface. If the two layers go on increasing I I TEGUMENTARY ORGANS. i82 in this way, however, the ultimate effect will be that, although growing in reality by its deep surface as before, the “ Lepidiiie” layer of the scale will appear to grow by its superficial surface, anti that addition of layers to the upper surface of the scale observed by Pro- fessor Williamson, will take place. If the ex- planation here proposed, however, be correct, this will form no objection to, but a confirmation of, Agassiz’ views. It will be well, however, with this clue to turn from the theory to the facts of scale de- velopment. All that I have observed leads me to con- firm Professor Williamson’s conclusion, that there is no real line of demarcation to be drawn between placoid, ganoid, ctenoid, and cycloid scales ; all these forms passing into one another. Indeed, I conceive that the only method thoroughly to comprehend the cycloid and ctenoid scales is to examine, in the first place, the so-called placoid and ganoid forms. Hermann Mayer and Leydig have shown (and the fact is readily verifiable) that the scales and spines of the Plagiostome fishes are formed by the gradual deposit of calcareous matter in processes of the integument, which are at first coated by the ordinary cellular ecdcron. These diverticula, in fiict, originally re.semble other papillae of the skin, and like them, are bounded by a structureless proto- morphic layer, marking the boundary between the cellular ecderon and the enderon. When the formation of the placoid scale commences, however, instead of the successive division and multiplication of the endoplasts and the cellulation of the periplast of the ec- deron, which before went on, a deposit of cal- careous matter takes place at the boundary- line, and the structureless band remains as structureless or “ basement” membrane, in- vesting the future spine. The dej)osit in- creases until the enderouic pulp occupies but a very small space, or even completely disap- pears, and the spine projects as a cylindrical or conical tubercle. When it has attained its full length, the deposit does not cease ; new calcareous matter is continually added to its inner extremity, but rather in the direction of breadth than of length, so that, eventually, an irregular broad plate is formed with the spine projecting from its outer surface {Jig. 80S.). Fig. 308. It is particularly to be remarked, however, that the projecting body of the spine being once formed, the calcareous additions which give origin to its base (c) gradually cease to be in exact apposition with the original protomorphic zone ; and in proportion as the base of the spine extends, have we a wider and wider interval, occupied by the tissue of the enderon, between its upper surface and the under surface of the ecderon (/). Examin- ing it in the perfect state, then, it would appear that the spine is included in a sac of the en- deron ; and this appearance is very much strengthened if dilute hydrochloric acid be added, by which the enamel layer {a) is dis- solved out, and the structureless membrane enclosing the spine rendered distinct ; while its continuity with that structureless layer which bounds the enderon is at once obvious. From its development, however, it is clear that this is a simple appearance, and that the apparent sac results from the projection in- wards of the extremity of this truly ecderonic structure. In fact, inasmuch as the base of the spine grows like its shaft by continual ad- dition to its inner surface, while its apex is unquestionably an ecderonic structure, this base might be considered to be enveloped in an involution of the protomorphic plane of the ecderon {Jig. 307. c). I Now suppose such plates as these to have | acquired their maximum in width and mini- i mum in height ; furthermore, imagine them to r be so closely set in the skin that the posterior edge of one over-rides the anterior edge of the ' one next behind it, and we have the exact ar- rangement of the scales in the cycloid and ctenoid fish {Jg. 309.).* Fig. 309. Scale of the Roach (^Leiiciscus.') ■ j A, section ; B, surface. | * The flexible cycloid scale of the eel presents an I exact parallel to the tooth-like placoid scale of flie ' skate, except that it is flat instead of conical, and ) that, in the adult state, the scale appears to be com- pletelj^ included in the enderon, and is 'wholly | covered by the cellular ecderon. I believe this J appearance of inclusion in a complete sac to pro- ,1 ceed simply from the smallness of the original point il of contact of the scale 'U'ith the cellular ecderon, || and the rudimentary state in -^vliich the wfliole organ , <1 remains. 1 • M.'. I J TEGUMENTARY ORGANS, 483 A careful study of the scales of that remark- able animal the Sturgeon, which exhibits in this, as in so many other characters, its inter- mediate position between Teleostian and Pla- giostome fishes, appears to me to throw still further light upon the difficulties of scale development. The scales of the sturgeon are large, slightly convex, rhomboidal plates, set obliquely in the skin, so that, while the posterior two-thirds of their surface are bare and hard, the anterior third becomes gradually softer from the pro- longation of the integument over it. The posterior surface continues hard up to its sharp edge, but it is supported below by a soft thick layerof integument, which passes on to the an- terior soft coat of the scale behind, and thus masks the real overlapping of this scale by the posterior edge of that which precedes it (fig. 310. b). Fig. 310. Scale of Sturgeon. A, one of the detached tubercles highly magni- fied ; B, the enth'e scale. The surface of the scale is shining and glassy. It is marked by a median ridge, whence it shelves upon each side, and by an elegant sculpturing produced by raised, hard ridges of the same nature, which radiate from the margins centrally, for about a fourth of the semi-diameter of the scale. In the region within this zone, the ridges gradually lose their regularity, the radiating lines anastomo- sing with one another and forming an elegant polygonal network. The soft surface of the in- tegument of the anterior portion of the scale, is raised into many minute papillae (7?g.310. a,o), which may be followed for some distance on to the hard portion. Furthermore, it exhibits scattered round spots, with projecting centres of the same appearance as the ridges, and like them feeling hard to the touch. If a section of the scale be made (_/?g.310. b), Its under surface will be found to have a conca- vity corresponding with the convexity of the up- per. If the section has passed through one of the ridges, it is seen that the osseous tissue of the scale is of two kinds ; a superficial homoge- neous-looking, dense, comparatively thin layer, and a deep, thick, laminated portion. If traced from the centre of the scale to its an- terior circumference the superficial layer loses its continuity, breaking up into conical bodies, which are the sections of the detached calca- reous spots mentioned above ; the deep layer thins out, its laminae gradually becoming fewer, and leaving a soft membranous space between their upper surface and the under surface of these spots. In the centre of the scale again, a series of rounded apertures are seen in a tangential section, the sections of canals which radiate through the scale and become more numerous and wider towards its margin. They are connected below with vertical canals passing through the laminated layer, and anteriorl}' they pass into the wide membranous space above referred to. There is no histological difference of any importance in the structure of these two layers ; each is composed of true bone with radiated cor- puscles ; the upper being more dense and ho- mogeneous, the lower less dense and lami- nated. If a section be made through several of the ridges of the upper surface, it will be seen that they are entirely composed of the hard homo- geneous osseous tissue. On their sides, how- ever, and in the valleys between them, more or less of soft integument remains, whose pigment masses give the valleys a dotted ap- pearance. On the other hand, a section of one of the detached tubercles shows, except in its consisting of osseous tissue only, that it is identical with a single spine of the Skate ifg. 310. a). It appears to me, therefore, that there can be no doubt that the ganoid, over- lapping scale of the sturgeon commences by an isolated p'acoid spine; that other spines are developed around this, and their bases uniting, constitute a placoid scale, between whose elevations little valleys, bridged over by the soft integument, remain ; that to the base of such a plate as this, continual additions of osseous laminas are made, the radiating Haver- sian canals being left between the first laminae and the superficial plate ; and finally that, extending in size, the anterior face of this complex scale becomes over-ridden by the preceding one. Complicated as it may ap- pear, it is obvious that all this structure results from the continued endogenous growth and union of the primary ecderonic calcareous deposits, which constitute, as it were, so many centres of ossification for the large scale. The final structure, however, is (if we leave out of consideration its histological character), to all intents and purposes, that of a cycloid scale ; and its mode of growth is identical with that of the large cycloid scale described by Prof. Williamson. The increase of the scale is concentric ; addition being made to its posterior, as well as to its anterior edge and surface ; the only difference being, that in the latter case the development of the upper layer is less rapid than that of the lower, while in the former I t 2 484 TEGUMENTARY ORGANS. they are coincident; that soft membranous separation therefore, which exists between the two layers anteriorly, is far less developed posteriorly ; and tire soft continuation of the scale which is flat anteriorly, is inflected pos- teriorly; the process of addition being other- wise the same. Suppose, now, that each detached calcareous centre of ossification as it is added to the posterior margin of the scale, instead of being flattened, were produced into a spine as in the Rays, then it is perfectly clear that instead of a cycloid scale, the result would be a serrated ctenoid scale. And this appears to be exactly what takes place in the scales of the perch, according to Prof. Williamson’s descri[)tion. From all this, I think, we arrive at Prof. Williamson’s conclusion, that fish-scales are essentially tegumentary teeth ; that like the latter organs, tiiey result not from the calcifi- cation of the cellular ecderon covering those folds of the integument, upon which they are developed and which correspond with the dental jmlp, butby a calcareous deposit taking place beneath this, in what represents a deep layer of the ecderon ; finally that it is, for the present, an open question whether the deep layers of all scales are produced by a con- tinuation of this process, or whether in some cases a deep truly enderonic structure may be added to this superficial ecderonic constituent to constitute tlie perfect scale. A process of the latter kind would, at any rate, find its parallel in the eventual union of the teeth of many fishes w'ith their jaws, and in that of tire plates of the chelonia with the vertebral elements. § 3. Histology of the tegumentary organs. — Having thus arrived at a general idea of the mode in which the various forms of integumen- tary organs are produced from the primary morphological constituents of every integu- ment, we have now to consider their minute histological elements and the mode in which these proceed from the indifferent tissue of which all organs are primarily composed. The tegnmentary tissues, like all others, are produced by the metamorphosis of the pe- ri[)last of the protomorphic or indifferent tissue from which they take their origin, the endoplasts, to all appearance, taking but little share in the metamorphic processes. The chemical metamorphosis of the periplast may be either into horny, chitinous, calcareous, or cellulose matter; in form it may become fibrous, laminated, vacuolated, bony, prisma- tic, 6iC. As a general rule, the endoplasts tend to disappear, pari pawif, with the metamorphosis in form and composition of the periplast; but the differences presented by different tissues in this respect have given rise to the esta- blishment of a distinction between what is called the process of conversion and that of excretion. For instance, in the development of a hair oi‘ of a nail, the elements of the pro- tomorphic layer evidently pass, as such, into the perfect substance of these organs; the periplast simply becoming horny, andthe endo- jilasts remaining for a long while, or even always, visible in the cornified tissue. This is therefore a process of ‘■'conversion'” of the protomorphic tissue. On the other hand, the chitinous coat of the lower Annulosa and the shells of the lamellibranchiate and gasteropod Mollusks arise in a totally different manner. The elements of the protomorphic layer do not pass into them entire, but they are formed, like the cuticula of a plant, or like the den- tine and enamel of the teeth, by the successive outgrowth of layers of the outer portion of the periplast. No endoplasts, therefore, are ever found in them, and there is no conversion of the protomorphic tissue, but a process of excretion. * At first sight this distinction would appear to be very decided, and likely to afford a good ground for the formation of definite sub- divisions of the integumentary organs into classes. Unfortunately, it is often difficult in practice to assure oneself in what way a given tegumentary organ has been formed. While the presence of endoplasts in a meta- morphosed tissue is good evidence of its having been developed by conversion, their absence is no proof that the tissue has been developed by excretion ; inasmuch as it may simply be due to their very early disappear- ance. In fact, if any one affirm that the shell of a Unio or of a Crustacean, notwithstanding the impossibility of detecting endoplasts in its youngest laminae, is in reality formed by the successive apposition of entire layers of the protomorphic tissue, in which the endoplasts disappear so early that they cannot be de- tected, it would be very difficult absolutely to disprove the assertion, though we might ask for evidence of its truth. Disbelieving in the doctrine of the special vital activity of the endoplasts, I confess the question does not seem to me to be of much importance, and I have only enlarged upon the subject because great weight has by high authorities been laid upon these distinctions. It appears to rne that the processes of conversion and of excre- tion grade one into the other, and that no real subdivisions can be based upon the oc- currence of either to the exclusion of the other. I will, however, take care to indicate what appear to me to be clear instances of each. I shall now proceed to consider the histological structure of the integuments of animals in the following order : — 1. Hydroid and Actinoid Polypes and Beroidae. 2. An- nulosa, including the Worms and Echinoderms. 3. Mollusca, including the Ascidians and Po- lyzoa. 4. Vertebrata. 1. Hydroid and Actinoid yolypes . — In these animals the integument consists either of a simple cellular ami vacuolated ecderon, or the outer layer of this is developed into a structureless coat, wliich may become thick- ened by repeated additions, and thus attain considerable dimensions. In the common * Using the word in the sense of “growth ovt,” not in the common perverted signification of fluid transudation and hardening. TEGUMENTARY ORGANS. 485 Cainparmlaria, for instance, the outer wall of the bull from which a polype is to arise consists, at first, of a mass of indifferent tissue. As development proceeds, the outer portion of the mass is converted into a structure- less membrane, which becomes detached from the body of the polype through its whole extent, and constitutes the future cell, the subjacent ecderon taking on the ordinary cellular structure. On the pedicle the same process goes on to a less extent, the struc- tureless layer becoming separated only at intervals, so that the pedicle acquires a ringed appearance. An integument of one or other of these descriptions is to be met with in all the Sertularian and Actinoid Polypes, and is obvionsly, in these cases, the result of a process of excretion. In the Meduscs and Beroidcc, on the other hand, where the integu- ment is thick and gelatinous, the ecderonic tissue is converted, as a whole, into what closely resembles rudimentary connective tissue, in which elastic elements and muscular fibres are developed. The presence of peculiar organs, called the ‘^Thread or Ur Healing cells" constitutes an extremely characteristic feature in the integument of these creatures. These Fig.^W. {fig. 311.) are composed of a delicate mem- branous sac (fl), enclosing a much thicker one (i), which is open at one extremity, the aperture being stopped by the end of a more or less irregular short stiff sheath (c), some- times giving attachment to several distinct rays or spines (d), applied together, which is fixed to the edges of the aperture, and oc- cupies the axis of the inner sac. To the ex- tremity of this sheath a long, frequently toothed filament is attached (e), and lies coiled up round the central sheath, and in close contact with the walls of the sac. The latter are very elastic, and seem to be tensely stretched by the contained fluid during life ; for, on pressure, the sac suddenly bursts, and its contents are evacuated so rapidly as hardly to allow of the process being traced. I be- lieve, however, that the long filament is pushed out by the side or through the axis of the central sheath, remaining still firmly attached to the latter, so that the result is the appear- ance exhibited in the accompanying figure (c), where the sac is seen empty, the long serrated filament being attached to the sheath, which, everted and with its spines spread out, is itself fixed to the margins of the aperture. The violent protrusions of these minute serrated filaments, aided, perhaps, by some aridity of the liquid of the sac, is in the larger kinds, such as those which exist in Physalia, exceed- ingly irritating to the human skin, and usually proves fatal to the minute creatures on wliich the Hydrozoic and Anthozoic polypes prey. Integument of the Annulosa. — The integu- ment of the lower Annulose tribes, of young forms and of the more delicate parts of a great majority of the higher Annulosa, con- sists of a thin structureless chitinous mem- brane developed from the subjacent cellular ecderon, in a manner essentially similar to what has been described in the Polypes. Leydig has particularly described this form ofinteguinent in Entomostracous Crustaceans, (Branchipus and Argulus) in insect larvae, (Corethra), and among the Annelids in Pisci- cola, Nephelis, Haemopis, Sanguisuga, Clep- sine and Lumbricus, where the integument consists of two portions — a deep cellular layer and a superficial layer, which is either abso- lutely structureless, or is fibrillated ; being in no case formed by the coalescence of the sub- jacent cells, but by excretion from them. A similar structureless excreted integument is found also in Planariae, Nemertidae, in many Cestoidia, Nematoidea and Trematoda, and, according to the late researches of Leydig, on Synapta, in the Echinoderms also. Where the integument is not very thin, and con- sists of several layers of chitinous matter, the added laminae commonly take on a fibrous structure. The Nematoid worms present par- ticularly good examples of this complication. Thus, for instance, the integument of Mermis albicans, which has lately been examined wdth much care by Dr. Meissner, consists of three layers, the middle of which is double. The outermost of these layers is either structureless or presents a distinction into transverse hex- agonal plates, each of which occupies ^ of the circumference of the animal. At the head and tail, small polygonal plate-like markings replace these, and such small plates could be detected, making up the large ones. Dr. Meissner calls them “ cells,” but expressly states that he never detected any nucleus in them, and it seems more probable that they are produced by modifications of the original external structureless layer, similar to those which, as will be seen, occur in the Crustacea and Mollusca. The middle substance of this integument is composed of tw'O layers of fibres one above the other. The fibres are parallel in the same layer, but those of the two layers cross one I I 3 48G TEGUMENTAKY ORGANS. another at right angles, so that they form two sets of opposite spirals. The fibres are sharply contoured, dense, and brittle, and those of each layer are divided into six sets, corre- sponding with the six sections of the body. At the sutures the fibres of each bend back upon themselves, and run in a parallel course to the opposite suture. The deep layer is the thickest ; it appears longitudinally striated on section, and may be split into lamellae of any thickness ; other- wise it is |)erfectly structureless. Ill the Nemertidae, according to the re- searches of Qnatrefages, the integument has essentially the same structure, consisting of a superficial structureless ciliated lamina, with deeper vacuolated and fibrillated layers. In the other Turbellaria the vacuolated struc- ture is predominant. This fibrous cliitinous integument is still better developed in the Insecta. According to Mayer (/. c.) the chitinous integument of Lucanus cervus is composed of glassy rods with sharply defined dark, paral- lel edges, which by their mutual apposition and anastomosis, and probably by the interposition of a connecting mass, form thin layers. The rods in each layer are parallel, but those of different layers cross one another at angles of from 45° to 90°; so that a horizontal section presents a sort of elegant cross-hatching, the lines of which are about 0'008 mm. apart. The outer surface of this laminated mass is invested by a transparent homogeneous sub- stance containing pigment, and above this by a layer of epidermic “ cells ” (O'OOo to 0 01 mm. in diameter), with'nuclei and nucleoli, their edges being separated by an intermediate substance. Internally, there is also a layer of epidermic “ cells ” which are polygonal from mutual pressure. They are without nuclei, but possess a short spine, arising from the centre of the cell, and ending by a sharp point. Quekett (/. c.) describes a similar structure, consisting of striated laminae, in the integu- ment of Dynastes Hercules. The integument thus described closely re- sembles that of the larger Crustacea (vide infra), and I should have placed it with them, except for the very distinct statement of Mr. Newport with regard to the development of the integument in Melbe. According to Mr. Newport’s researches, the integument of the young Melbe is at first composed of polygonal nucleated cells, the largest of which is about Woo in diameter. As the animal grows, the nuclei divide and subdivide by a process of fission, and the integument becomes composed of several layers. After awhile, the deeper of these undergo a fibrous meta- morphosis, and constitute a fibro-cellular structure, which gives attachment internally to the muscles, while the external layers continue to grow, and to be reproduced as distinct cells. II this were the mode of development which obtained in all Insecta we must con- sider their chitinous integument to be pro- duced by conversion of the ju'cviously e.x- isting cells of the eederon. However, Leydig’s statements are equally decided, that the in- tegument of Corethra presents no appearance of cellular origin, and the question may, there- fore, for the present, probably be considered undecided. The calcified integument of the Crustacea presents the same general structure as that of the other Annulosa, consisting of superposed chitinous, more or less fibrous lamellm, the outer of which are infiltrated with a calcareous deposit. In the small transparent Crustacea, as we have already seen, the integument is composed of structureless layers, developed by excretion on the surface of the eederon, and even in the largest forms, the minute hairs, &c., present precisely the same ap- pearance ; but in the thick integument of the Decapoda, certain layers of the shell have been described, not without considerable show of reason, as possessing a cellular organisation (Carpenter). I have carefully examined the shell of the common crab in relation to this point, and the following are the results of my investigation. It appeared to me in the first place, that, without seeking for a moulting crab, the structure of the integument in its uncalcified state might be readily ascertained by ex- amining the soft membrane connecting the articulations of the limbs, which, as is well known, is continuous on either hand with the calcareous integument, and passes into it. In a section of this soft layer (fig- 312. a), I found from within, outward, 1. The enderon (a) composed of connective tissue, excavated by vascular channels, and containing nume- rous aggregations of pink and yellow pigment, frequently disposed in a stellate form, or even forming anastomosing net-works along the ru- dimentary elastic fibres of the tissue. 2. The surface of this (b) was constituted by a proto- morphic layer, consisting of a homogeneous substance containing cndoplasts (c), w'hich sometimes adhered to the enderon, sometimes to the hard integument, when the latter was detached. 3. Superficial to this, wms the chitinous layer of the integument (c) com- posed of a number of laminae of great deli- cacy, and not more than aoVtr of an inch apart. The deep laminae were much softer than the superficial, and the outermost lamina of all was hardest, and of a brownish colour, constituting the structureless epidermis of Carpenter and Lavalle. In section, the deep laminae (b) presented only an indication of perpendicular fibrillation; but this became more marked superficially, the outer part of the section appearing closely striated. The deep laminae, when stripped ofi', presented no definite structure, but theyreadily fell into plaits ; while the superficial laminae ap- [)eared dotted over. I sought in vain for any appearance of endoplasts in the deep layer, where, however, had they existed, they must have been readily detected ; and I therefore conclude, that the chitinous lamellte are formed from the subjacent eederon, by a process of ex- cretion. It should be remarked, however, that 487 TEGUMENT ORGANS. a minute polygonal areolation is observable at times upon the most superficial “epidermic” layer. I do not know IVom what cause this A to E, from tlie crab ; f, g, from the shrimp. proceeds, but the areolae are certainly not cells. Such is the structure of the soft inter- articular integument, in which I could find no calcareous matter. If it be traced into the hard calcified shell, the only alteration observable is, that a dark calcareous deposit takes place, the earthy matter being infil- trated, as it were, through the laminae. The deposit affects, however, only the middle layers, the extreme outermost being left as the “horny epiderm;” while a variable number of the inner laminae remain as a more or less thick, soft coating upon the inner surface. These soft layers may be stripped off as a parchment-like membrane, with the muscles, and their relations to the enderon are then readily examined. They are here as struc- tureless as where they constitute the deep layer of the inter-articular membranes. The structure of the calcified layer has been carefully described by I)r. Carpenter, who showed, that in the crab and lobster they are traversed by tubules identical with those of dentine, and pointed out the error of Lavalle in regarding these as fibres. There can, I think, be no doubt, that in the crab and lobster. Dr. Carpenter’s doctrine is correct ; but I am equally of opinion, that for other Crustacea, such as the shrimp, M. Lavalle is right. I believe, in fact, that the tubular structure is produced by the horizontal lami- nation giving way, as the calcareous matter is deposited, to perpendicular fibrillation of the chitinous matrix, and that, eventually, the uncalcified fibrils disappear, and leave tubules in their piace. That at least appears to be a natural conclusion from the fact, that the perpendicular fibrillation of the soft tissue becomes more and more marked externally ; and thus, by decalcifying the calcified shell, we obtain horizontal separable laminre com- posed of short perpendicular fibres. The colouring matter has always appeared to me to be generally diffused through the upper layer, and not to be confined to what Dr. Carpenter describes as the “ cellular layer.” The latter is a very thin stratum, made up of only a few of the superficial laminre, which I have found to be most readily observable bj' detaching with a sharp knife a very thin scale from the upper surface of the crab shell. It is composed, exactly as Dr. Carpenter has figm’ed it, of regularly polygonal, often six- sided areae, frequently presenting a darker radiating patch in the centre, and, at first sight, irresistibly suggesting a true cellular structure. I believe, however, that it is in reality nothing of the kind, but that, like similar appearances in the molluscan shell, this is simply the result of the concretionary man- ner in which the calcareous matter is de- posited. We have seen, in fact, that there are no such appearances in the deep uncal- cified layers, nor in the thin layers which invest the minute transparent appendages — considerations which appear to me to be in themselves decisive against the cellular nature of these bodies. In addition, decalcification brings to light no endoplasts in the “ cells,” but in their place we observe clear polygonal spaces in the membrane (y%. 312. d) which present the same dots (section of tubules) as those which exist in the sim[dy laminated por- tion of the integument (yfg. 312. e). Finally, it the decalcified scale include a sufficient num- ber of layers, it is easy, by altering the focus of the microscope, to trace the areolation in- wards, until it becomes gradually fainter, and disappears, passing into the ordinary dotted laminm. I believe, then, that the “cellulai’” layer, results from a peculiar additional deposit of calcareous matter in the uppermost layers of the shell ; and this view is strikingly confirmed by what may be observed in the shrimp. The integument in this crustacean (e. g. the cara- pace) has exactly the same general structure as that of the crab, consisting of hard upper and soft deep layers, which are dotted and striated, and not tubular. The former owe I I 4 488 TEGUMENTARY ORGANS. their liarclness to a generally diffused, trans- parent, calcareous deposit, which allows the previous dotted structure of the larainse to he perfectly obvious. In some parts and in the superficial layers, this deposit is struc- tureless and homogeneous (fig. 312. g, a), but in other parts the youngest layer presents very delicate polygonal meshes, whose area; were about in. in diameter (fig.‘3\2. F, a). De- calcification completely destroys this appear- ance ; so that I imagine it to be caused merely by the mode in whicli the primary deposit in the membrane takes place, the areolae becoming almost immediately fused together by further dejiosit. Through these homogeneous hardened outer layers thus constituted, there are dispersed more opaque spots (fig.‘.i\2.v,(i,b'), more or less rounded in their outline, and varying in diameter from in. or less, to ten times that size. Tlie smallest of these bodies have e.xactly the appearance of cells (fig. 312. F, b), consisting of a dark centre, with a circular more transparent wall, and every variety of form may be observed between these and large masses, sucli as that figured (Jig. 312. g, U), witli a lobulated laminated circumference, and an irregidar centre, composed of small masses like dentine globules. In the former the dots of the original tissue may be still seen ; but in the latter they are not traceable and seem to be obliterated. If dilute hydrochloric acid be added wdiile the object is still under the microscope, however, these bodies are gra- dually dissolved out with effervescence, and the structure of the place they occupied is found to be identical with that of the other portions of the integument. They are, therefore, nothing but concretions of calcareous matter, whose deposit has taken place in a peculiar form, quite independently of the primary structure of the part ; this form being, in the smaller concretions, most deceptively cell-like. It appears to me that this case, in which the assumption of structure without cell develop- ment may be so plainly demonstrateil, has a most im])ortant application, not only to the mode of formation of Crustacean and Mol- luscan shells (vide infra), but to the develop- ment of the teeth, strongly confirming, I think, the view which I have taken of that pro- cess. Integument oftheMoIlusca. — Thesoft surface of the body of the Mollusca in general is con- stituted by an ordinary, commonly ciliated, cellular eederon, which needs no special de- scrijition. The hard or soft shells which so many of them possess, arise iti two modes ; the calcareous and horny integumentary append- ages being, I believe, invariably produced by excretion, while the Ascidian test, which con- tains cellulose, is formed by conversion. It will be advisable to treat of the structure and histological development of these two forms separately ; and, first, of the Excretionary integument of the Mollusca. — This is to be met with in its simplest form in the Polyzoa.in which the integument (ectocyst of Allman) is formed by a structureless membrane containing imbedded calcareous or silicious particles.* An admirable example of the calcareous integument formed by excretion is to be found in the shell of Unio and Anodon. The outer surface of the shell in these Lamellibranchs is, as is well known, covered by a brownish or greeni.sh irregular membranous substance, the so called “epidermis” of the shell. This substance, however, by no means constitutes a single membrane ; on the other hand, the surface of the shell is marked by an immense number of closely set, more or less parallel, concentric lines, some of which appear to be formed by rugte of the “epiderm,” while others are the free edges of epidermic laminae cropping out under those of older date. Viewing this surface of the shell by transmitted light with a low power, a number of polygonal closely-set are® come into view on depressing the focus through the thickness of the e|>iderm. The inner surface of the shell has, for the greater part of its extent, a pearly or nacreous lustre ; but along the gape of the shell, at a distance of from less than one line, to as much as two or three lines, from the free edge, the nacreous appearance ceases, and we find, instead, a brownish hue similar to that of the epiderm, and becoming gradually more intense till the very margin is constituted by a flexible brown membrane continuous and identical with the epiderm on the exterior. If the surfiice of the flexible zone be examined as before, its outermost portion appears quite homogeneous ; as we pass gradually inwards, however, dots appear in it, and the hard portion of the brown zone presents |)olygonal arese, precisely resem- bling those under the epiderm on the outer sur- face. Where the nacreous appearance com- mences, these areas disappear, becoming ob- scured by an opaque white substance, which is marked by elevations and depressions, corre- sponding with, though less prominent than, the principal ones upon the external surface. If, now, a section perpendicular to the surface and to the concentric lines be taken, and viewed in the same way by reflected light, the cause of the various apjiearances which have been described will become obvious. It will be seen that the thick middle of the shell is composed of three substances; of a very thin external brown layer, the “epi- dermis,” and of two other layers more or less equal in thickness ; an external, composed of minute polygonal prisms or columns set per- pendicularly to the surface, and an internal, which looks structureless, with a fracture like loaf sugar. The outer prismatic layer pre- serves its thickness as far as the “ brown zone” above described, and then gradually thins out into the flexible marginal membrane. The inner nacreous layer, on the contrary, gradually thins out, and ceases at the com- mencement of the brown zone. The ends of the prisms are, therefore, bare in the brown * I am indebted to Mr. Busk, whose extensive researches on these animals are well known, for the information on which this statement is based. TEGUMENTARY ORGANS. 489 zone, whence the polygonal areolation ob- served in it ; while its colour arises partly from the brown epidermis shining through, partly from a slight tinge of the same kind which runs through the prismatic substance, and renders it distinguishable, even to the naked eye, from the intensely white nacreous layer. Thin vertical sections of these shells pre- sent the following appearances under a high magnifying power. The external edge is con- stituted by a delicate brown band, the “ epider- mis,” in which no structure of any kind can be detected. Within this is the pris- matic layer, a dense transparent substance marked by strong parallel lines which run perpendicularly to the surface and either extend completely through the layer, or termi- nate by joining some other within it. In the former case, the spaces which they enclose appear like the sections of prisms (of of an inch, more or less, in diameter) : in the latter, they resemble longer or shorter cones whose bases are turned outwards. A number of such short cones are usually interposed between those ends of the prisms which are in contact with the epidermis. Internally, or at the line of contact of the prismatic with the nacreous layer, the lines either remain parallel or converge. The prisms are readily broken aw'ayfrom one another, and in this case, or in a sufficiently thin section of tlie whole layer, they are seen to be traversed by very closely set pa- rallel transverse lines about xouto apart. Each prism, however, does not possess a set of striae peculiar to itself; on the other hand, the parallel lines stretch without interruption through the whole length of the prismatic layer, as if the prisms were not there. A horizontal section of the prismatic layer pre- sents, as has been said, a coarse polygonal reticulation corresponding with the lines of contact of the prisms. The substance of the latter ajtpears granular, but without any other structure in fully formed portions (/g.313. A). Wlien a section of the prismatic substance is acted upon by dilute acid, the calcareous matter is extracted, and a membranous frame- work is left, presenting all the structural cha- racteristics of the original tissue, except that the prisms are now hollow, and from their trans- verse striations have been well compared by Dr. Carpenter to the scalariform ducts of plants. This membranous residuum readily tears up into lamintB, each of which corresponds, usually, to a number of the fine horizontal striae. The white nacreous substance — membra- neous shell substance of Dr. Carpenter — which constitutes the interior of the shell, presents, in a vertical section, a horizontally striated appearance identical with that of the prismatic layer, and when macerated in acid it breaks up into Kiorresponding laminae. In fact, if we leave out the vertical markings which give rise to the appearance of prisms in the latter, the two structures are identical. This point appears to me to have been overlooked and to have given rise to the impression that there is a much greater histological difference between the prismatic and membranous sub- stances, than really exists. The examination of the line of junction of the two substances {Jig. 313. b), however will at once show their fundamental identity. The ends of some of the prisms will be seen in fact to project beyond the others into the membranous sub- stance; but it will be observed that the hori- zontal lines of the latter pass without interruption through the prisms, and therefore that the laminae of the two structures are identical. If we reduce these facts to their simplest expression, it vvill result that these shells are composed throughout of superficial thin membranous lamina;, the outermost of which remains as epidermis, while the inner receive a deposit of calcareous salts. Next comes the question, however, how are the structural dif- ferences between the prismatic and membra- nous layers produced. Dr. Carpenter, in his well-known Essay, propounded the doctrine that both varieties of shell structure are the result of the development and coalescence of cells sup- plied by the mantle of the mollusk ; these cells remaining permanently distinguishable and coalescing in rows, in the prismatic struc- ture, but bursting and becoming confused into a homogeneous tissue, in the membranous substance. Nor, indeed, would it have been very easy in 1848 to arrive at any other con- clusion than this, to which so great a number of appearances at first sight tend. Enabled, however, by Dr. Carpenter’s great kindness and liberality to form my own judgment from his beautiful preparations, and having also worked over the fresh shells for myself, I have come to very different conclusions. I will not say that occasionally cells may not be en- closed in shell, but I believe I am in a posi- tion to show that, as a rule, shell-growth is not a case of conversion, but one of excretion, cells not being in any way directly concerned in the matter. We may consider, first, the growth of the shell as a whole ; and, secondly, that of its three constituents. Inasmuch as we know, that the shell of the young Unio or Anodon was once as thin as, or thinner than, the “epidermis” of the adult shell, and smaller than the smallest area, bounded by a concen- tric line on its outer surface ; further, since we know that no addition is made to the outer surface of the shell directly ; it is clear that the shell must grow in size by addition to its margin ; in thickness, by addition to its under surface. Furthermore, since the ex- treme margin of any shell is constituted by the horny “ epiderm,” internal to which is the gradually thickening layer of prismatic sub- stance, constituting the brown zone, within which again is the white nacreous area, formed by the superposition of membranous layers over the fully-formed thick prismatic sub- stance ; from all this, it appears to be equally 490 TEGUMENTARY ORGANS. certain that any given spot of the mantle of a young bivalve must give origin, directly or indirectly, first, to “epiderm;” secondly, to prismatic substance ; and, thirdly, to nacreous substance ; so that, on c.xamining the tree edge of a growing shell, we ought, since the “epiderm” is structureless anil transparent, to be able to observe the gradual formation of the prismatic substance upon its under sur- face. This is, in fact, the case. Fie. 313, a, represents such a free edge of the^shell of Anodon, a being the direction of the flexible zone ; b, that of the ])erfect prismatic sub- stance. Fig. 313. A to c, Unio ; D, Helix. Dr. Carpenter describes the appearances here figured in the following terms (/. c. p. 8.) ; “ Although the prismatic cellular structure has not yet been actually observed in process of formation, yet certain appearances, which are occasionally met with in the marginal portions of its newest layers, throw great light upon its mode of growth, and indicate its strong resemblance to cartilage in this respect ; for in these situations we find the cells neither in contact with each other, nor polygonal in form, but separated by a greater or less amount of intercellular substance, and presenting a rounded, instead of an angular form (_^^^314. c). Upon looking still nearer the margin, the cells are seen to be yet smaller and more separated by intercellular substance, and not unfrequently we lose all trace of distinct cells, the intercellular sub- stance presenting itself alone, but containing cytoblasts scattered through it. This appear- ance has been noticed by myself in Pinna and Unio, and by Mr. Bowerbank in Ostrea; so that I have no doubt that it is general in this situation. We may, I think, conclude from it that the cells of the jirismatic cellular sub- stance arc developed, like those of cartilage, in the midst of an intercellular substance, which at first separates them from each other, that as they grow and draw into themselves the carbonate of lime poured out from the subjacent surface, they approach each other more anil more nearly ; and that, as they attain their full development, their sides press against each other, so that the cells acquire a polygonal form, and the intercellular substance disappears.” I have given Dr. Carpenter’s statement at length, because it appears to me to express very distinctly the interpretation which one is at once tempted to put upon the appearance, but which I must reject for the following reasons; — In the first place, if we examine that portion (a') of the margin beyond the smallest granules {cytoblasts, Carpenter), it is seen to be either absolutely structureless or obscurely striated, not a trace of a cell or endoplast being anywhere visible. Secondly, if any dilute acid be added under the micro- scope, the apparent nuclei and cells vanish with effervescence, and leave behind them clear empty spaces, of exactly the same shape and size as they themselves had. Thirdly, the supposed cells have a peculiar concen- trically or radial ly-striatcd structure, resem- bling sections of urinary calculi on a small scale, and still more the corresponding bodies in the integument of the shrimp {supra.) For these reasons I think it must be granted that the appearances in question, how- ever cell-like, are, in reality, not the expres- sion of the development of a cellular struc- ture at all, but merely that of the mode in which the deposit of calcareous matter takes place in the membranous basis of the shell. In fact, I believe that the calcareous matter appears first in small and distinct globules (the “ cytoblasts”), and that more or less concentric deposits take place round these, the result of which is, that the membranous basis is more and more displaced, and that the deposited masses eventually come almost into contact. The regularity of the ultimate pris- matic structure results from that of the di.s- tances of the granules primarily deposited, and the even rate of addition to each subse- quently. There appears to me to be but one inter- pretation to be placed upon these facts; viz. that cells as such do not enter into the for- mation of the sliell of the Naiades at all, but that it is constituted by the successive excre- tion of membranous laminae from the surface TEGUMENTARY ORGANS. 491 of the epidermis of the mantle.* The outer laminre retain their membranous nature, only becoming so far altered as to assume the horny aspect of the so called “ epidermis ; ” in the next laminee, which are added to the inner surface of the young shell, calcareous matter is deposited in granules, additions to which are made in such a manner as to con- stitute the cellaeform concretions, and ulti- mately, the process going on in the same way in successive layers, the prisms ; in the inner- most laminae, finally, the calcareous deposit results in an even, homogeneous, folded or striated layer. By scraping with a sharp knife the inner surface of the shell oT Anodon, freshly detached from the mantle, I have obtained a distinct tough membranous la3'er, scattered through which were a vast number of close-set irregular granules of calcareous matter. A similar structureless layer without the granules constitutes the outermost surface of the ecderon of the mantle (fig- 313. c, b') and may occasionally be detached as such. Such a layer consisting of the thickened outer portion of the periplast of the ecderon of the mantle is by no means an anomalous structure, as we have a formation of exactly the same kind in the “ cuticle ” of plants, and in the chitinous lining of the intestine in Insects ; and I believe that the shells of mollusks in general consist simply of a multitude of thin layers successively thrown off, super-imposed and coherent, all the peculiarities of their struc- ture arising from subsequent modifications, which are altogether independent of cells. This view is in perfect agreement with all that is known of the nature of the shells of larval Gasteropoda and Acephala, which are invariably either of an absolutely structureless, thin, transparent, membranous character, or at most present a delicate striation. It may be added that not the slightest trace of a cel- lular structure is to be met with in the pellucid shells of the Heteropoda and Pteropoda. So much for the two primary forms of shell struc- ture, the membranous and the prismatic. A most interesting variety of the former is the nacreous (mother-of-pearl) lining which is presented by many shells, both of Ace- phala and Cephalopliora. The pearly iri- descence proceeds, as Dr. Carpenter has well shown, from the folding of the membranous layer into close plaits, and not, as has been supposed, from the alternate cropping out of calcareous and membranous layers. Dr. Car- penter proved this by decalcifying with acid a layer of nacre from Haliotis splendens. The iridescence remained; but if the plaits of the layer were pulled out by stretching it with needles, the iridescence disappeared. Another variety of structure usually, but not alone found in the membranous shell substance, is the tubular. “ All the different * This is, after all, only a return to the opinion of Poli, whose observations on shell structure are remarkably accurate, and should never be over- looked. See his Testacea utriusque Sicilim. Pars prima “in qua de Testarum natiua atque affec- tionibus disputatur.” forms of membranous shell structure are oc- casionally traversed by tubes which seem to commence from the inner surface of the shell, and to be distributed to its several layers. These tubes vary' in size from about the to the iTiVo of inch, but their general diameter in the shells in which they most abound is about 4-Aro of an inch. The di- rection and distribution of these tubes are extremely various in different shells; in general, when they exist in considerable numbers, they form a network which spreads itself out in each layer nearly parallel to its surface, so that a large part of it comes into focus at the same time in a section which passes in the plane of the lamina. From this network some branches proceed towards the nearer side of the section as if to join the network of another layer, whilst others dip downwards, as if for a similar purpose ” (Car- penter, 1. c. p. 14.). In other instances the tubes run obliquely through all the layers. The former structure was found by Dr. Carpenter in the outer yellow layer of Anoinia ephip- piium ; the outer layer of Liima scabra and in Chama, the latter in Area, Peciuncidus, and Trigonia. In the latter case, the tubules are not continuous, but are seen under a high power to be formed by rows of isolated vacuities, one for each lamina ; corresponding, I imagine, with the appearance, “ as if they had arisen from the coalescence of lineally arranged cells,” pointed out by Mr. Bowerbank and Dr. Carpenter. Having already given what are, I believe, sufiicient reasons for denying the existence of cells of any kind in molluscan shells, I need hardly add that I cannot think this to be the true explanation of the mode of development of these tubules. In fact, I con- sider that the tubular shell structure is iden- tical with that of dentine, and has precisely the same origin ; its tubuli arising not from cells, but like the canaliculi of bone, by a process of vacuolation in the calcified tissue. I regard the structure and mode ofdevelopment of the Molluscan like that of the Annulose shell, in fact, as evidence of the strongest and most unmistakable kind in favour of the views with regard to the formation of dentine which I ventured to put forth in my essay “ On the Development of the Teeth.” Tooth and shell completely represent one another, structure for structure; Nasmyth’s membrane is the homologue of the “ epidermis,” the enamel that of the prismatic structure, the dentine, that of the membranous structure ; and all three are produced without the inter- vention of cells by the differentiation of pri- marily structureless laminee. The existence of tubuli in the prismatic substance is not mentioned by Dr. Carpenter, but I have no- ticed them very distinctly in one of the sec- tions of Pinna from his cabinet. Finally in Rudistes and the sessile Cirrho- pods. Dr. Carpenter has pointed out the ex- istence of a peculiar cancellated structure “like that of Pinna on a large scale” only that the segments of the prisms are hollow instead of solid. These hollow prisms are 492 TEGUMENTARY ORGANS. covered externally and internally by a struc- tureless layer. To complete this view of the different varieties of shell structure, it may now be interesting to consider the mode in which they are combined in the shells of the vari- ous classes of the Mollusca. In the Bra- chiopoda, the calcareous shell is composed entirely of membranous laminm, which are superimposed at a very acute angle with the surface of the shell, and are further remark- able for being thrown into sharp folds ttoVo to of an incli apart, perpendicular to their planes. In tlie great majority of the recent species again, all the layers of the shell but tlie outermost are perforated by canals ■0006 to ‘0024 of an inch in diameter, each of which contains a coecal process of the mantle, corresponding with those processes which we have seen into tlie cellulose tunic of the Ascidians ; the shells of Lingula and Orhicida are composed of horny laminae perforated by oblique tubuli like those of dentine (Car- penter, 1. e.). The shells of those families of Lamellibranchs, in which the lobes of the mantle are more or less united, are similarly composed almost entirely of laminated mem- branous shell substance, e. g. Mytilus, Mo- diolus, Tridacne, Isocardia, Conchacece, Nym- phncecc. The tubular structure is met with in the ArcacecB, in Lithodomus, in Cardium, and has generally a marked relation with the costa- tions or sculpturing of the outer surface ; the membranous and prismatic structures are combined in the Myaccce and SolenacecB, and in those genera which have the lobes of the mantle disunited, as Ostrea, Unio, Pinna. In the Gasteropoda the shell substance is invariabl3’ membranous, but the laminaj of which the shell is composed, usually three in number, are marked by parallel lines into rhomboidal bodies, which are described by Dr. Gray as crystals, by Messrs. Bowerbank and Carpenter as elongated, mutually adhe- rent cells. I believe that neither of these expressions is exactly correct, but that these bodies have the same origin as the prisms of the lamelhbranchiate shell; a conviction in which I am strengthened by finding concen- trically laminated bodies, like those of the Lamellibranchiates, upon the inner surface of the shell of Helix {fig. 313. o). In Patella the middle layer is composed of perpendicular prisms, like those of Pinna. Chiton resembles it in this respect, but the outer layer is here composed of fibres parallel to the surface, and is pierced by short canals. In Haliotis, calcified plaited laminae alternate with structureless horny layers, in immediate contact with which, says Dr. Carpenter, “is a thin layer of large cells of a very pecu- liar aspect.” Dr. Carpenter considers that the plaited laminae are cellular in this shell also. Among the external shells of the Cephalo- poda that of Nautilus has an external “ cellu- lar ” layer as in Mya, and an internal nacreous layer like that of Haliotis. The shells of all Lamellibranchiata, Brachio- poda, and of the majority of Gasteropod Ce- phalophora are external, being from their very origin never included in any involution of the mantle. It is different, however, with certain Cephalopoda and pulmonate Cephalophora, in which the shell commences its development as an internal organ covered over by the outermost layer of the mantle, and may either remain so enclo3edduringlife(e.g. Sepia, Limax), or ulti- mately become naked as in Spirula and Clau- silia. Although, however, these shells are truly intei'nal (a distinction which, as I have endeavoured to show, carries with it some important conclusions),* yet the careful ob- servations upon their development in Sepia by Kolliker, and in Clausilia by Gegenbaur, appear to furnish abundant evidence that they are still truly ecderonic structures, and that they bear the same relation to ordinary shell as a nail bears to a horny epidermis among the higher animals. We know, in fact, that the nail, though to all intents and purposes mere cornified epidermis, is at first an internal structure, being covered over bj- the outer layers of the foetal epiderm. A nail remaining so covered would correspond with the shell of Limax or Sepia, while an ordinary nail represents that of Clausilia. Gegenbaur, in fact, has shown that the shell of the latter mollusk commences at first like that of Limax by the deposition of a layer of calcareous par- ticles in the midst of the cellular ecderon of the mantle beneath its outer layer of cells. The shell of Limax goes no further than this stage, while in Clausilia (and probably in Helix, &c.) it gradually increases by addition to its under surface, and finally bursts through the cellular investment which takes no share in its formation. It is the same with Sepia. Here the internal shell, or sepiostaire, is com- posed of two layers, a dorsal and a ventral ; the former, according to Kolliker, is a thin membrane composed of slightly wavy, parallel, somewhat dark fibrils 0'001-2 " broad, which frequently appear to be composed of still more delicate fibrillm. So far as this membrane cor- responds with the ventral layer, it is covered on both surfaces by a thin structureless la- mina of carbonate of lime, which has a pearly aspect on the ventral surface where it is not covered by the ventral layer ; while it is gra- nular on the dorsal surface, and on the ventral, where it is covered by the proper ventral layer, presents ridges to which the plates of the latter are attached. The thick ventral kwer of the sepiostaire is composed of lamella; set at a very oblique angle to the dorsal layer, and united together by close-set partitions at right angles to their surface. Acted upon by acid, this portion of the shell leaves behind it a membranous skeleton of exactly the same form, but presenting no further structure. Young embryos present merely a fibrous rudiment of the dorsal layer. The ventral * See Memoir on tlie Morphology of the Cepha- lous Mollusca, Phil. Trans. 185'2. 493 TEGUMENTARY ORGANS. layer is formed by the successive deposit of calcareous laminae inwards. When the first lamina has been formed, a deposition of small cylindrical bodies takes place upon its inner surface. These increase, widen and become ramified at their extremities, forming ramified- columns. A second calcareous lamina is now formed, connecting their ramified extremities, upon whose under surfiice the like process takes place, and this is repeated until the ven- tral layer has attained its full thickness. The ramified columns are regularly transversely striated; with the age of the shell additions are continually made to their lateral dimen- sions until they coalesce and constitute the septa of the perfect shell, upon which the strise remain visible. Kolliker was unable to find any cellular structure in the columns or laminae themselves, but describes a layer of nucleated cells under the shell, which he regards as the agents in its secretion. Some researches recently made by H. Muller (Gegenbaur, Kolliker and H. Muller, 1. c.) corroborate this view'. He finds the shell of the Loligidae invested by an ex- cessively vascular membrane, which is almost wholly covered by a layer of epithelial cells towards the shell. On the dorsal surface they are for the most part rounded ; on the abdo- minal surface, and particularly towards tlie anterior point, they form narrow cjdinders w hich attain a length of as much as 0‘07"'. They appear to give rise to the structureless layers of the shell. The lateral styles of the Octopods present similar relations. The structure thus described, though appa- rently so widely different from that of ordinary mollusks, does not really differ very widely from the cancellated sheli structure of Rudis- tes, &c., or still better of Pleurorhynchus as described by Dr. Carpenter. If we leave out the sides of the hollow prisms in the latter shell in fact, it will correspond exactly with one lamella of the ventral layer of the sepiostaire. For a comparison of the shells of Spirilla and Belemnites with those of Sepia and of Gasteropods, I must refer to Dr. Carpenter’s Memoir so often cited. 2. Conversionary integument of the AloUusca containing cellulose. — This form of integument has hitherto been found in the Ascidians alone, in which the existence of cellulose was first detected by Schmidt in 1845. Schmidt’s dis- covei-y was confirmed, the fact of the existence of cellulose in all the genera of Ascidians deter- mined, and the chief morphological characters of their test set forth in the memoirs by Ldwig and Kolliker “ Sur les Enveloppes des Tuni- ciers,’’ w’hich appeared in 1846, since when further investigations have been made by Schacht and by myself. I must refer the reader to these papers for an account of the various opinions which have been entertained with regard to the structure of the Ascidian test, as I can only lay before him what are in my belief the facts of the case. The test of the Ascidians is never composed of pure cellulose, but consists of an animal membranous matrix, to which the cellulose has the same relation as the calcareous salts have to the membranous basis of bone or of shell. The cellulose is, in fact, diffused through the membranous matrix, thoroughly impreg- nating it. This membranous nitrogenous matrix in which the cellulose is deposited, presents great diversities of structure in the genera of Asci- dians, representing, in fact, almost every known tissue. Thus in one genus w'e have a test re- sembling cartilage ; in another, like bone ; in a third, like connective tissue. It may either be without vessels or traversed by branched and ramified vascular processes of the body. It is in all cases, however, a product of the metamorphosis of the ecderon of the outer tunic or mantle and, complicated as its struc- ture may be, corresponds morphologically with the shell of other mollusks, or with the epi- dermis of the higher animals. In fact, if a section be made through the outer tunic and test of an Ascidian, as iny?g. 314. a, taking care not to disturb the natural relations of the parts, we observe at the line of contact between the outer tunic and the test («) an arrange- ment of the parts very closely resembling w hat exists at the junction of the derma with the rete Malpighii in the human skin. The outer tunic, like the former, is constituted by bundles of rudimentary connective tissue which run inwards to form sheaths around the muscles, leaving between them spaces, the sinuses of the blood vascular system, while externally they fuse together into a homogeneous substance containing endo- plasts, which is thrown into processes and passes insensibly outwards into a layer of similar substance, with very close-set endo- plasts almost perpendicular to its surface, which forms the commencement of the proper test. Externally to this rete iMalpighii, the deposit of cellulose commences ; the tissue un- dergoing at the same time a fibrous metamor- phosis. The line a is therefore a protomor- phic line, and the test is the product of the growth and conversion, by deposit of cellulose within its elements, of a true ecderon. The separation of the ecderon (or test) from the enderon (outer tunic) takes place with great readiness in some Ascidians, as Phallusia,&c. ; while in others, such as Boltenia, many Cynthias, Salpae, Ac., it can be effected with considerable difficulty, or not at all, and this difference has even been raised to the rank of a zoological distinction, the Ascidians having been in consequence divided into Monochito- nida and Dichitonida. I believe, however, that in all those Ascidians whose test is un- provided with vessels, it is, normally, closely adherent to the outer tunic, and I am inclined to think that this is equally true even of those forms, such as the PhallusiEe, in which in preserved specimens the test and outer tunic are so commonly found detached from one another. Here, however, as the test is pro- vided with an abundant vascular supply pro- ceeding from one point of the body, it may normally become separateil elsew here. Care- 494 TEGUMENTARY ORGANS. fill examination of fresh specimens can alone decide this point. Fisr. 314. The simplest form of Ascidian test is that presented by the Salpas. Here, we have merely a gradual growth of the periplast and a deposit of cellulose within it, the endoplasts either remaining as such or becoming sur- rounded by cell walls. The resulting tissue, in fact, is identical with cartilage, if we suppose cellulose to have taken the place of chondrin. In the Pyrosoinata, the test has a struc- ture which, on the one hand, resembles bone, on the other some forms of fibro-carti- lage. The endoplasts, in fact, have become surrounded by cell walls, which are produced into long, frequently anastomosing processes {fig- 314. d) ; these retain their animal com- position, while all the immediate tissue is strongly impregnated with cellulose. This is the fundamental structure of the test in the Phallusite and Clavelince also ; but here an additional complication results from the development in tlie substance of the test of a series of rounded cavities, which gradu- ally enlarge until they almost come into con- tact, and give rise to a spongy texture. The intervening septa at the same time frequently become obscurely fibrous {fig. 314. c). Now these “ vacuolae,” whose origin and nature ap- pear to me to show their identity with the “ cancelli ” of bone developed from cartilage, have been described by Lo wig and Kolliker, and by Schacht as cells ; and the latter has even stated that they possess a nitrogenous lining membrane. This is, however, a mistake, arising from the imperfect operation of the reagents by whicb the cellulose is detected ; it is simply less abundant close to the cavities of the vacuol®, but may with care be demon- strated to exist up to their very edges. Botryllus, Synoicum, Syntethys, Boltenia, and the Cynthise, present a new series of ap- [tearances : here the periplast of the eederon is metamorphosed into fibres, which, however, are not composed of pure cellulose, but of a nitrogenous substance impregnated therewith. In Synoicum the test is soft, and presents very much the structure of some forms of rudimen- tary connective tissue. We find, in fact, a more or less distinctly fibrillated basis with scattered endoplasts ; some of these are in- vested by round granulous nitrogenous cell- walls, while in others the cells are spindle- shaped and prolonged at each end into fibres (representing thus the elastic element of or- dinary connective tissue), or they may be stellate. Botryllus, Syntethys, and Boltenia, present a similar structure, varying, however, in the extent to which the nitrogenous cell- walls on the one hand, and the periplast im- pregnated with cellulose on the other, have undergone development. Thus the periplast is broken up into very obvious fibres in Bo- tryllus, while in Boltenia the fibrillation is pale and indistinct. On the other hand, I have nowhere met with so great a develop- ment of the nitrogenous cell-wall as in Synoicum. In Boltenia a more or less distinct lamina- tion makes its appearance in the test, and this peculiarity, as well as the fibrous structure altogether, attains its maximum in the Cyn- thite. In Cynthia papillate, for instance, the middle substance of the test is composed of numerous, very obvious laminae, which con- sist of fibres directed alternately parallel with, and perpendicular to, the surface of the test (314. i?.) At first sight, they appear as Lowig and Kolliker have described them, to be decussating sets of longitudinal and radiating ; but on a. careful examination of their sections I invariably found that the apparently radiating fibres bend round as they approach the apparently longitudinal set, and in fact pass into the latter. The longitudinal bands are, however, no thicker at one end of a section than at the other, so that the trans- verse fibrils cannot be merely given off from them. A transverse section, again, exhibits the same appearances as a longitudinal one ; so that I think the fibres must in reality have a more or leAs regularly circular arrange- TEGUMENTARY ORGANS. 495 ment around the centre of the spaces occupied by the radiating bands, the apparently longi- tudinally fibrous bands arising merely from the decussation of these circular fibres. Great numbers of granular corpuscles (en- doplasts?) are scattered through the midst of the “ transversely fibrous ” spaces. In Cynthia pomaria, Ldwig and Kolliker de- scribe peculiar “ cells ” in the inner layer of the test, consisting of such corpuscles sur- rounded by a thick circularly fibrous w'all, and the existence of these bodies appears to be additional confirmation of the view I have taken as to the mode in which the fibres in Cynthia papillata are disposed. If in the latter, the fibres were disposed more closely around particular corpuscles, the test would, in fact, break up into just such circularly fibrous cells. I have hitherto described only the structure of the middle, most characteristic portion of the Ascidian test ; it is next necessary to notice the inner and outer surfaces ; the former of which is ordinarily said to be covered by a cellular epithelium, the latter by a more or less structureless horny epi- dermic layer. The so-called epithelium is, I believe, in all cases merely the innermost unmetamorphosed layer of the ecderon, corresponding with the rete Malpighii of the “ epidermis ” of higher animals. As the Ascidian integument is ordi- narily examined (i. e. in spirit specimens), it is in the condition of the macerated integu- ment of one of the higher animals, and just as the “ epidermis” of the latter may or may not, if stripped off, bring away with it the deepest layers of the rete, so the Ascidian test, when detached from the outer tissue, may or may not retain the corresponding structure. The horny so-called “ epidermis,” on the other hand, is a structure well worthy of at- tention, as a similar element is, as we have already seen, to be met with in the widely different integuments of other Mollusca. In ail Ascidians I have found the outermost sur- face to be formed by a structureless homoge- neous layer, which contains less cellulose than the subjacent tissue, and often has a brownish horny aspect. In many Salpae, Phallusiae, and Cynthias, this outer layer constitutes merely a tough wrinkled investment. In others (Synoicum, Boltenia) it is prolonged with the subjacent la}'er into spines and processes, but without being much thickened. In other Bolteniae again, and in various Cynthise, it is greatly thickened, and almost by itself consti- tutes large spines or even tesselated plates. In Cynthia papillata {Jig. 314. b), the whole outer surface of the test is covered with spines (a), whose bases expand into polvgonal plates, which strongly resemble the spines of the Rajidse, to which reference will be made below. The brown substance here appears to have invaded the subjacent tissue, leaving spaces for the pre-existing endoplasts, so as to give rise to a structure precisely resembling the bone of the Plagiostomes, while to com- plete the resemblance, the pointed extremity of the spine is marked by lines which pass from its central cavity, parallel with one another, to the surface. I am not sure that there are tubes, but otherwise the appearance is exactly that presented by the pseudo-den- tine of the integumentary spines of the skate. It would appear, according to Milne Edwards, and the late observations of Krohn, that the rudiment of the mantle exists in the ovum of Phallusia before the cleav- age of the yolk commences, as a structureless pellucid coat, containing solitary or aggregated greenish cells; and it would seem as if the outer structureless layer with which we are at present concerned, arose from this coat, w hile the main thickness of the mantle is the product of the metamorphosis of the subse- quently developed ecderon. From all that has been said, I think it re- sults that the Ascidian test is formed from the ecderon of the animal by a process of conversion which consists in the deposit, through its periplast, of cellulose, and a coin- cident morphological change which may re- sult in the production of a tissue essentially resembling either cartilage, bone, connective tissue, or even dentine ; and that, therefore, an attentive study of the integument in this class alone is sufficient evidence that mere structure is no proof of the ecderonic or enderonic nature of any given organ. Integument of the Vertebrata. — In these animals there are two classes of integumen- tary organs, differing in structure, chemical composition, and mode of development. These are, 1st, the homy and glandular tegu- mentary organs produced by the conversion of the cellular ecderon ; and 2nd, the calefied tegumentary organs which appear very fre- quently to be developed by a process of exci'ction. Conversionary horny organs. — If a section be made of the integument of any mammal, it will be seen to be composed, leaving out of view its various appendages, of tw'o principal portions, the enderon or derm, and the ecderon or epidermis. The latter, separated by a more or less distinct transparent line from the for- mer, is internally composed of a homogeneous soft substance, in which are dispersed nume- rous oval or rounded endoplasts, set more or less perpendicularly to the surface of the enderon. Further outwards, they gradually become more distant and a cavity is de- veloped round each, so that the ecderon becomes distinctly cellular. Still more ex- ternally the cellular periplast becomes changed in composition, being converted into a denser horny substance, and the change usually takes place so suddenly that the horny external portion (epidermis) is sharply marked olF optically, and can be readily separated me- chanically and chemically, from the internal unaltered soft portion, the rete Maljlighii. The cell cavities at the same time become flattened, and by degrees almost obliterated, apparently by the pressure of the subjacent growing tissue ; but the endoplasts remain, and may always be detected if the horny layers are 496 TEGUiMENTARY ORGANS. distemleci and rendered transparent, b}’ the action of acids or alkalies. The horny stratum of the epidermis is therefore the result of the conversion of the walls or periplast of a whole layer of the cells of the ecderon into horn. The hard structures of nails, hoofs, and horns (1. c. horny sheath of the horns of Ruminants) are developed in exactly the same manner; nor am I aware that any tissue enters into these organs, which is not entirely produced by the horny conversion of a cel- lular 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 shrift of a hair is composed of three distinct structures, an external, the cuticle; a middle, the cortex; and an internal, the medulla. Fig. 315. A, B, n, K, F, from the nose; c, from the head. The cuticle {fig. 315. c, i), 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 (5) having the ajtpearance of minute rhomboidal cells, joined end to end ; the inner («) 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 oppressed 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. i 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 {fig. 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, h) 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 lay'er 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. 49 ' 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 strite 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 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. Supp. 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 aider (a) and the inner (c, d) ; 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 older 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 the rete 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 (y?g. 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- pjerforate 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 endo- K K 498 TEGUMENTARY ORGANS. plast. In the human hair sac there are usually only one or two laniinac in this layer, but ill 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 tliat of these cells, the inner are converted into the imperforate layer, wliile 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 [dates, at whose edges the clefts are commencing {fig- 315. f). It would appear, therefore, that tlie 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 com[)letely 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 cederon. The development of these from the indifterent tissue of the outer rootsheath, may be very clearly traced. The periplast first becomes enlarged and marked oft’ 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 eederon, — 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 sulistance composed of polyhedral horny cells. Fig. 317. Feathers of the neck of the common Fold, A, free edge of pulp ; B, c, medulla and cortex ;; D, transverse section of cortex ; e, a barb, willi, barbule partly detached from pulp; f, cornified relf' from rootsheath ; g, horny diaphragms in thf| quill. ' The section of the shaft of a fully-fonaec} feather presents exactly these constiiuenbjl except the cuticle ; the centre is occupied b|l medullary siibstanee (^fig. 317. B,a), coinposeiJ * See Brdcker (Reichert, Bericht. Midi. Archiv 1849). TEGUMENTARY ORGANS. 499 of a coarsely granular horny substance exca- vated by pol}'gonal cavities of about toVo 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 {fig- 317. d) appears as a clear, homogeneous or slightly granular mass, dotted over by minute aper- tures, about TW3WO 'n. in diameter, and ao’oo in. apart. In a longitudinal section, on the other hand (y?g. 317. c, /;), 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 quill 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 (y%. 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 arete ; it then acquires a horny consistence, and a stronger and stronger definition along the lines of demarcation, until polygonal “cells” (as in 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 {Jig. 317. b) of the pulp (c) with recently formed cor- tical substance (6), 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 tubnli 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, Untersuchungeii, &o. 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. F),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 membrane” of^the feather sac {supra, 5 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 acconnt of those organs, snch 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 “ raucous 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 ccecal glands are scattered over the whole surface of tlie 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 Molliisca 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 Puhnonata, and receives glands on each side. The existence of cutaneous glands in the Cephalopods appears doubtful — at least, H. Muller 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 Uig. 318. The cvtancnus 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 {fig. 318. b). These lead directly into spherical sacs (ifig. 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 bj' 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 {fig. 318. A. g.) {vide infra). Nerves (/) and vessels ))enetrate 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 Kblliker 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 ccecal tubes varying, in man, from Too to TTWo o* tin inch in 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 Bergniann and Leuckart to have an irritating property in Triton. f Asclierson : Haut-driisen d. Frosche, Miiller’s Arcliiv, 1841. Czermak: Haut-nerven d. Frosche. Ibid. 1849. 501 TEGUMENTRAY ORGANS. 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 cceca, which are very difficult to discover ; while on the ball of tbe 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- cvpenser and Polypterus 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 tbe 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 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 Czermak, 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 vvoukl 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 (Ou 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 (Muller), and in the truly bony semi- canals which are attached to the scales of the lateral lines of many fishes.” * Forthedetailsof thevarious modes in which Ganoin, true osseous tissue, and those va- rieties of tubular, more or less dentine-like tissues, to which Prof. Williamson 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 laminrn, 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 diagonall}'. 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 ; Eochen imd Haie, 1852, K K .3 302 TEGUMENTARY ORGANS. crease in size by the external addition of new concentric laminae; 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 matri.x in the Fish, the Mollusk, and the Crustacean alike ; while the deep uncalcificd layers of the scale are represented by the “ horny ” lamina? 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 luvertebrata 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 [)lates 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 eederon, 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 II. Miiller *, who has recently made some careful investigations on this subject, there lie beneath the cellular eederon in these ani- mals : 1st, a fibrous layer, usually colourless, but occasionally white and glittering. 2nd, the layer with the chromatophora ;«/). 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 * Beridit, &c. Zeitschrift fiir Wiss. Zoologie. 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 Fw. 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 iiTegular 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- 3 19.«), 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 luvertebrata (Annelids, Trematoda, Echinoderms, Crustacea, Mollusca). In other luvertebrata and in the higher Verte- brata, the pigment is confined to the eederon. In Fishes and Reptiles, however, a well- marked layer of pigment lies at the surface ot 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 extraordinarj' 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. Miiller, (whose observations T 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 difterent 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 Chamteleon, as is well known, presents similar phenomena. PapillcB 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 wlien 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. Miiller) are very probably both vascular and nervous papillm like those of fishes. Among the Vertebrata, fishes present large projecting papillte, particular!}' 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- fiice 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 eederon, so that a horizontal section of the eederon is like that of a horse’s hoof. In man, again, the papillae are, as is well knowm, so abuudantasto have given rise to the term pars iMinllaris, for the superficial layer of the eederon. 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 Leydig for showing that in certain Crustacea, Insecta, and Mollusca, it is very similar to what occurs in the vertebrate classes. Thus in Argidiis 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 satina, Branchipus stagnalis, and in the Heteropod Mollusk Carinaria, the termination of the tegumentary nerves is es- sentially similar. The larva of the Dipterous insect presents even jjeculiar 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 cellteform 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 Kdlliker 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 b}' 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 piu'poses 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. Kdlliker, who doubts their special relation to the tactile function, on the other hand, prefers to call these bodies, a.ii/e corpuscles. They are simply ovoid masses of im- K K d 501 TEGUMENTARY ORGANS. perfect connective tissue occupying the centre of the papillae, and further distinguished by having their endoplasts and imperfect elastic Fi^. 320. A papilla with its Corpusculum tactus surrounded hy three vascular papillce. 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 Kdlliker 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 feet, usually described under the latter name; but their small size and superficial position,thepaucity 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 a[ipearance of capsules aud 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 Leydig has discovered that these Savian 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- tifid series of researches, Leydig has shown that the mucus is furnished by the cellular eederon, 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 more 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 fishes, 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 Chimiera. Leydig insists with great justice on the identity 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 Leydig and myself. See Quarterly Journal of Micr. Science, No. V., and Siebold and Kblliker’s Zeit- schrift, B. v. Heft 1. TEGUMENT ARY ORGANS. 503 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 tactiis, 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” (Jig. 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. Vibrissa from the snout of the 3Iouse. a, “ sclerotic ” sac ; b, hair-sac ; c, nerve-trunk ; d, muscular fibres. Considering the difterent habits oflife of the mammal and the fish, I think one cannot but be struck wdth the similarity of plan between their vibrissa? 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 w'hich 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. Pacinian body (b) 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 tegumentary striped muscle, which attains an enormous development in the hedgehog, while a mere rudiment of it remains in man, as the platysma myciides. Here, however, the striped ‘Jeaucier” 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 enderon. — 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 tlirough the en- deron, and would almost seem to take the place of fat. In nudibranchiate mollusks, such as the Doridm, 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 oi the Echinoderms, is composed of calcareous networks of this kind, and globular masses of calcareous matter are scattered through the enderon of theTseniadae, though the clear spherical bodies observed in these worms are by no means always of this nature. Whether these enderonic 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 decideil by a very careful examination of the mode of growth of their so-called “dermal’’ bones. BinuiOGKArHY. — General Works. — IJeusinger, llistologie. Quekett, Lectures on Histology. Vertebrata. Gnrtt, Untersucli ungen liber die liornigen GebiUle d. Menschen u. d. llaus-sauge- thiero (Muller's Archiv., 183G). Idem, Vergleichende Untersuclumgen iiber die llaut der Menschen und d. Ilaus Saugethiere (iMtiller’s Archiv., 1835). Sleijer, Ilaut d. Cetaceen. Meyer, Baa d. Haut des Gurtelthieres (Muller’s Archiv., 1848.) Et>1e, Lehre von d. Ilaaren, (Consult also for the Hairs, &c. the works cited in Henle's Allgeineine An- atomie, and Kiittiker’s Mikroscopische Anatomie.) Feathers : — Dutrochet, Observations sur la Structure et la Regeneration des Plumes (Journal de Physique, Ixxxviii.). F. Cuvier, Obseiwations sur la Structure et Developpement des Plumes (Mem. du Museum, xiii.). Michet, (in Reil’s Archiv., xiii.). Sozith, Art. Zoology ( Encyclopcedia Metropolitana.) Scates and integumentary organs of fishes. — Leeuwenhoeck, Arcana Naturai. Reaumur (Mem. de 1 Acad. Roy. des Sciences, 1716). Mandl, Sur les Ecailles des Poissons (Annales des Sciences Naturelles, 1831).). 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 Pish (Phil. Trans. 1849). Williamson, On the Stracture and Development of the Scales and Bones of Fishes (Phil. Trans. 1851). Leydig, Histologische Bemerkungen iiber den Polyp- terus bichir (Siebold und Kblliker’s Zeitschrift, 1853). Leydig, Beitrage zur Mikroskopischen An- atomie und Entwickelungs Gesediichte der Rochen u. Haie, 1852. Leydig, Haut der Silss-vrasser Fische (Siebold u. Kolliker’s Zeitschrift, 1851). Leydig, Schleira-kaniile d. Knochentische (Muller’s Archiv., 1850). Peters, Report on the Memoirs of Mandl and Agassiz (Muller’s Archiv. p. ceix. 1841). Rathke, Fleber die Beschaffenheit des Lederhaut bei Am- phibien und Froschen (IMuller’s Arebiv., 1847). Czermah, Ueber die Haut Nerveu des Frosches (Muller’s Archiv., 1849.) Axnulosa- — Lavalle, Annales des Sciences Naturelles. Carpenter, Report on the Blicroscopic Structure of Shells (Rep. Brit. Assoc. 1848). Mayer, Ueber den Bau d. Ilornschale der Kafer (Muller’s Archiv., 1842). Newport, On the Natural History and Development of the Oil-beetle Meloe (Liun.Tan Transactions, 1845-7). Leydig, Ueber Argulus foliaceus (Siebold und Kbllikcr, Zeitsch. B. II.). Leydig, Zur Anatomie von Piscicola geo- metrica (Zeitsch. I.). Leydig, Ueber Artemia salina und Branchipus stagnalis (Zeitsch. HI.) Hollard, Recherches sur les Caraetbres anatomiques des De- pendances de la Peau chez les Animaux Articules (Revue et Mag. de Zoologie, 1851). Meissner, Beitrage zur Anatomie und Physiologie von Mennia albicans (Siebold und Kblliker’s Zeitschrift, 1853). Quatrefages, numerous Memoirs in the Annales des Sciences. Mollusca. — Poli, Testacea utriusque Siciliae, 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 Kbl- 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. Wiederlc'ducnde Tliiere, — a well defined 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 ])i’ovide for the ruminating act. Coecum large. Placenta generally in the form of cotyledons. Feet ungulate and bisulcate. This order forms two natural divisions, compri.sing the Hornless ruminants (akera- toj)hora. 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 clas.sification 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 : — I. Camelid.^e II. Cervidad III. Antilopidje - IV. OiGOSCEEIDiB - V. BoVIDiE - Camelus - Auchenia - ( Moschus - -! Cervus (Camelopardalis - {Antilope - Catoblepas {Capra Ovis Bovis Linn. Illiger Linn Linn. Linn, Linn. Smith. Linn. Linn. Linn. The Camelidce 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, — . 1 1 *■33’ 1 1 . 1 1 ’ p. m.- 2 2 1 1 3 3 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 Skeleton of the Camel. (From Panderand D’Alton.) have the toes distinct at the ti|) from the or cotyledonoid form of placenta. Professor sole.”* The uterine aiul foetal membranes Owen has demonstrated another remarkable are unprovided with the ordinary ruminant character arising out of the non-development 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 tlie lower six cervical vertebrae. This ana- tomical arrangement occurs in no other existing tribe of maminifers, but in an aber- rant form of fossil pachyderm (^Macrau- chcnia). Dr. Owen has detected the same anomaly, and has thus established an ad- ditional connecting link between the Pachy- dermata and Ruminantia. In the classification of the Cervidte 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, — The Musk-deer tribe have in addition two long and conspicuous canines in the upper jaw, jjrojecting in the males below the mouth. {Jig. 330.). The male Kijang or Muntjak {Ceivus mimtjac, Zimmerman) has likewise two prominent canines in the upper jaw Fig. {a. Jig. 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 ffigosceridae {Qigosceros, Pallas) we have brought together the closely allied genera Capra and Uvis. 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. 325. Skeleton of the Cow. (From Pander and D’ Alton. The Bovidaz present few anatomical pecu- liarities not shared by the preceding genera. As regards external configuration, fiowever, 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 {Jig. 33f). The forehead is usually straight and elevated, the orbits are placed wide apart, and the muzzle, except in Bovida;, * See “ Glands 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 The occij)ital bone (1 \,fg. 326.), as in most of the mammalia, is originally divided into four, one superior, one inferior, and two lateral pieces (\\', 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 (I 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 Cervidte they are of great size and some- times four in number, in which case two remain small. In CEgosceridae and Bovidse 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 Bovidre, where it lies below, and is separated from the frontal suture by the intercalated and narrow wedge-shaped parietal bone. The Qigosceridae 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 ip. Jig. 335.). It is broader in the goats than in the sheep. In Bovidae the parietal does not extend so far forward (6. Jig. 327.). In the Giraffe the lateral processes of the parietal are narrowed Fig. 327. Skull of the Ox, viewed 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 bones (8) are oflarge 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 laterally. (FromSpix.) by a transverse suture, w'hich 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 KUMINANTIA. vateJ posteriorly in BovidEe (c, fig. 327.) and prolonged toward the occipital crest, in the formation of which they apj)arently con- tribute,— a circumstance giving rise to tlie 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 Iti 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 o f the sknll o f a Gira ffe. (From a spe- cimen in Lond. Coll. Siirg. 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 Cervidm generally, the canal opens at the upper surlace by a longitudinal furrow (jig. 329.), but this is more particularly marked in Bovidae ( /?g. 333.). In regard to the cranial sutures in Cervidte, 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 surround 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” (^g. 320).*' The sjihenoid (12) articulates, except in Bovidae, with all the eranial 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 Cervidte 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 s[)henoid 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, Lemons d’Anat. Comp., 2'*^ edit. tom. ii. p. 36G. RUMINANTIA. 511 Front view of the shill 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 shill 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 Bovidee 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,Jig. 327.). Part of the body of the [)Os- 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 CEgosceridse the latter openings are somewhat compressed. The os etkmoides has the same relations as usual, its cells being greatly developed in the Gii'affe. 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 (fg. 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 tlie zygomatic apophysis, there is a large round foramen immediately above the external meatus. In Cervidsc and Antelo- pidac tlie post-glenoid apo[)liysis 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- lopidre 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 (y%. 331.), and, as we have before stated, in the I^ig. 331. Llamas also. In CEgosceridre 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 Bovidse the temporals (e. Jig. 327.) are partially hid by the overhanging frontals : they develope short and strong zygomatic apophyses ; their bullae (e', Jig. 327.) * F. Cuvier. are much narrowed, and their styloid pro- ^ cesses are divided at the tip into several needle- shaped points. W, Bones oj the face. — These are more nu- % merous than those of the cranium, and we shall only notice the more important of them in detail. ?! The nasals (7), which vary much in size, f • are long in the true Camels, a little spread "f ! out at the base and deeply notched in front, ,1 ! forming together three salient points : in the C, \ Llamas we find them very short and broad posteriorly. In Cervidae generally, the na- A f sals are much extended lengthwise and bifur- V.7 cate anteriorly { fig. 329.) : in the Muntjack > J {C. Munfjac) and in the Giraffe they are par- i ticularly wide apart at the upper or posterior M border (Jig. 331.) ; and in the latter species >tj they exhibit a gradual but marked rising ^ j towards the central eminence of the frontals >3 {Jig. 328.). The naso-frontal suture in the X-m genus Moschus is much denticulated. The y# nasals are very short in the Eland or Canna {J. areas, Pallas), and in the Moose-deer w (C. aloes, Linn.) In QHgosceridae and Bo- vidae the bones of the nose are moderately long, and slightly convex above in the former w' {f,Jig. 335.) ; in the latter family and in the m ' Goats they are divided in front {J, fig. 327.) ; 3. but in the Sheep they form together a single ?' V-shaped process {7, Jig. 332.). ^ Fig. 332. Slmll of the Sheep, front mew. (From Lend. Coll.' * Surg. Museum.) x,*- The hitermaxillanes (1) are usually much 7 prolonged, but they do not develope incisive teeth except in the Camelidac, and a few other species. In the Camels properly so called, and ^ in the aberrant cervine genus Moschus, the^^ outer rami of these bones incline at the supe-/,. rior part almost vertically upwards {Jig. 334.); j but in the Llamas they maintain througli-'; out an oblique direction as obtains in rumi-; Hants generally. In both genera they are com-7 ■ pressed laterally, and brought round in front, so as to resemble in some measure the beak oL a bird ; the incisive foramina are remarkablyii t RUMINANTIA. 513 small. In ffigosceridse 335.) and Cer- pardalis they exhibit a slight concavity at the vidffi, for the most part, the ascending rami in- upper margin. In this last named genus the in- cline at a very oblique angle, and in Camelo- tennaxillary bones are very long and extremely J%.1333. Froyit view- of the skvM of an Ox, with the right horny sheath detached from the core. (From LonJ. Coll. Surg. Museum.) attenuated at the tip {Jig. 328.) ; in Bovidae, on the other hand, they are of diminished length (g. Jig. 327.), straight, of great thick- ness and broad in front, giving to the muzzle an aspect characteristic of the group ( 1 ,Jig. 333.). The incisive openings are elongated, capacious, and widely separated in the Giraffe {fig. 328.), they are still more so in the Stags {fig. 329 ) and Antelopes {fig- 34-2.) ; and in OEgosceridas and Bovidae they form enormous clefts, especially in the latter {Jig. 333.). Several genera have a small free space be- tween the converging points of the inter- maxillaries; and this is particularly noticeable in the Giraffe ( fig. 328 ). The bones in question are of great length in the Eland or Cape Elk, and in the Moose-deer. The maxi/laries (2) usually carry six molars and premolars on either side ; excep- tions, however, occur in the Camelidae where one of the premolars is absent, and in this family, as also in the aberrant genus Moschus and in the male Cervus Muntjac, canines are developed {a. Jig. 331.). In all ruminants they send processes of greater or less extent to the inner and under part of the orbit, in the situation where these bones lie partly concealed by the jugular or malar bone. As regards the bones themselves there are few other peculiarities worthy of notice ; but we may remark, in passing, that in the Giraffe the maxillaries project more than two inches beyond the tips of the nasals. The sub- orbital foramina (6) are placed in the Came- lidae a little before the orbits and above the alveolar ridge, at a point corresponding with the line of juxta-position of the middle and third premolars (j%. 334.). In the Giraffe and in other Cervidae the infra-orbital aperture is seen further forward, on a level with the Siipp, first premolar : in Qigosceridas it is on a line with the second {/i, fig. 335.). The Bovidae have a long suborbital canal opening above the first premolar (/^', Jig. 327.), as in the Stags and Giraffe. Fig. 334. Lateral view of the skull of the Camel. (From a spe- cimen in Lond. Coll. Surg. Museum.) The lachrymals (3) are directed forward, and occupy a considerable extent of the cheek ; at their point of union with the frontal, nasal, and intermaxillary bones there is usually left a vacant space more or less patent. This space in the true Camels is stated to be of large dimensions ; but, out of four crania we have examined in reference to this particular, in one only was this opening distinctly visible ; in the others the extension of the periosteum, which closes the cavity in front, had ossified, leaving only a few small foramina, irregularly disposed. In the Llama the opening is significant and communicates with numerous sinuses. In regard to the true lachrymal passage in Camelidee this is represented externally by a single foramen placed directly behind the orbkar ring; but there is in the Camels a second hole which I. L 514. RUMINANTIA, is quite distinct, being connected with the spheno-palatine canal at about half an inch from its orbitar orifice. In Moschus the lachrymal bone is large; it does not articulate with the nasal, and there is no facial cavity : the foramen is close to and within the orbi- tal ring {Jig. 330.). In Camelopardalis the bone is moderately large and is separated fiom the nasal in front by an interspace {fig. 328.), which, in the single specimen we have dissected, is of a triangular form, and measures an inch and a half in length, and five-eighths of an inch in breadth. According to the experience of Professor Owen this vacant space is invariably present, though not always equally conspicuous. At the orbital ring, midway between the frontal and maxillary lines of articulation, there juts out a small tuberosit}', which is bounded on either side by a shallow groove ; and from this [joint the bone is carried downwards and backwards to form, in conjunction with the molar protuber- ance of the maxillary and the inner border of the malar bone, a shelf-like floor to the an- terior half of the orbit. In the specimen just mentioned there exists but one lachrymal foramen, which is of large size, infundibuliform, and situated nearly an inch distant from the anterior border of the orbital ring. In the Stags the lachrymals are hollowed out on the cheek for the reception of the special suborbital glandular apparatus, and they are of large size, but do not touch the nasals, being separated from them by a very ex- tended membranous interspace {fig. 329.). In the orbit these bones exhibit relations similar to those indicated in the Girafte ; but there are two foramina, one placed on each side of the lachrymal tuberosity, beneath which they intercommunicate. The posses- iF>g. sion of “tear-pits,” or suborbital sinuses, is not shared by all the Antelopidas, and in those species in which they do occur the degree of depression in the lachrymal bone is very vari- able, being in some comparatively shallow, in others well marked ; the same observation applies to the open space situated imme- diately above. Respecting the absence, pre- valence, or coexistence of these morphological peculiarities we may, according to M. F. Cuvier, divide this family into three groups : in the first are to be reckoned those which have both a lachrymal depression and a facial interspace, such as is seen in the Gazelle {A. dorcas, Pallas), the Stein-boc {A. iragulus, Licht.), and the Grys-boc {A. melanotis, Licht.) ; in the second, those possessing the “ tearpit,” but having no vacant space such as occurs in the genus Catoblepas, the Koba {A. koba, Ogilby), the Cambing-outan {A. Sumatrensu, Desm.), the Ciiickara {A. quadricornu, De Blainv.), the Caama (A. caama, Cuv.), and the Buhale {A. bubalis, Pallas) ; in the third, those having the inter- space, but no depression, such as takes place in the Reh-boc (//. caprcolus, Licht.), the Chamois (yl. rupicapra, Pallas), the Canna {A. oreas, P. ), and the Nil-ghau {A. picta, Ik). The CEgosceridae have the lachrymals very large and of great length, this being es- pecially the case in the Sheep, where they ar- ticulate with the bones of the nose{i.fig. 335.). The Goats have usually a small open space on the cheek, both of the above genera being provided with a small tubercle at the anterior margin of the orbit. The foramina are placed within the ring and are remarkably large in the Sheep. The lachrymals in Bovidae are of still greater size, and very conspicuous {fig. 327.); they develope prominent antorbital 335. Skull of the Sheep, viewed laterally. (From Cuvier.) tubercles and have the connecting sutures on the face marked by dee|)ly toothed inter- lineations. There is no membranous inter- space, and the foramen, which is funnel- shaped, is situated at the margin of the orbital ring immediately behind the tubercle. The malar or jngidar bones (4) do not offer any very striking peculiarities. They are bulky and strong in the Camelidae, and of great breadth below the orbit : in the Llamas they advance further forward upon the cheek than in the true Camels, and the zygomatic RUMINANTIA. 51a apophj'ses are very short. In Moschus the post-orbitar apophysis is of considerable size — that of the zygoma somewhat narrower (fig. 330.). In Antelopidse and Cervidae generally, the malars are slender, and have short zygo- matic apophyses: this latter feature is espe- cially noticeable in the Giraffe. They are broad and of great thickness in CEgosceridce (fig. 335.), in which family and in Bovidte they are much prolonged upon the cheek, in the latter being a little bifurcate anteriorly at the maxillary line of suture (fig. 327. j. The palatines (6) are largely developed. In Camelidae, where the roof of the mouth is very long, the palatal laminre have a great longitudinal diameter ; in the Llamas the transverse suture extends to a level with the anterior border of the first true molar ; the central palatal cleft, which is angular, reaches the front margin of the middle or second true molar, while the lateral notches proceed as far only as the anterior border of the last molar. In Cervidce the palatals occupy a large square space at the inner and lower part of the orbit, but this is not the case in the Giraffe, where this part of the bone is rather smaller and lies partly concealed by the shelf-like process of the lachrymal and the molar prominence of the maxillary bone. The lateral fissures at the guttural margin of the palate are very wide in this family and extend deeper into the roof of the mouth than does the mesial clel't. These three clefts are placed in the Giraffe nearly on the same level, the central fissure having a semi- circular outline. In the Muntjack deer the two lateral notches are much in advance of the mesial cleft. The guttural portion of the combined palatines in Qiigosceridae is of great breadth, and the fissures, which are not very deeply, notched, are all very nearly on the same level (n, fig. 336.) : the orbitar or Fig. 336. Base of the cranium of the Sheep. (From Lond. Coll. Surg. Museum.) ascending plates are large and square, but deficient at the upper part, where there intervenes a space or hole analogous to the spheno-palatine foramen. This opening is particularly capacious in the Sheep. In Bo- vidae the palatines occupy about a fourth part of the oral roof : the ascending or suborbitar portions, which are of enormous bulk, are almost entirely hid by the lateral overlapping of the posterior border and supra- molar prominences of the upper jaw ; the palatal notches are very deep, especially the two lateral, which are remarkably broad and somewhat in advance of the mesial. The vomer and ossa spongiosa sen turbinata, in consonance with the general extension of the facial bones in ruminants, are chiefly particularised for their longitudinal develop- ment. In the orbits the wings of the vomer are represented by very small laminae, which appear at the upper border of the opening corresponding to the spheno-palatine fora- men. In certain of the Stags the azygos portion descends between the pterygoid apophyses of the sphenoid to a level with the palate, dividing the mesial fissure in two and contributing to form in this region a backward expansion of the oral roof. The spongy bones will be referred to when de- scribing the organ of smell. The inferior maxilla or jaw'-bone proper is of great length; in which respect it follows the course of the bones of the upper jaw. Between the canine and first premolar of either side there is in the typical ruminant, an extended interval, at which part the body is constricted ; and immediately in front of the mental foramen (r, fig. 337.) it again ex- Fig. 337. Jaw-hone of the Sheep. (From Loud. Coll. Surg. Museum.) pands toward the alveolar margin to give support to the teeth. The angle of the jaw is prominent and rounded posteriorly ; in this situation also it is comparatively thin and broad, as in Solipeda. The coronoid pro- cesses of the rami (g, fig. 337.) are particu- larly long curved backward, and a little hooked at the summit. The glenoid apo- physis is short, and the facet flat and slightly concave, to admit of free lateral motion on the wide convex articular surface of the temporal zygoma. The sigmoid notch is L L 2 516 RUMINANTIA. shallow. In the Camel there is an additional process at the parotid border {w. Jig. 334.), analogous to the similar but more marked apophysis in Carnivora. Cranial peculiarities. - — Under this head we proceed to notice certain arrangements re- quiring further attention, and in the first place the remarkable sinuses which exist in the skull of the Giraffe. Though these be nothing more than an extension of the Fig. ordinary frontal, ethmoidal and sphenoidal cells, yet their significance is not the less apparent or important when considered in a physiological or teleological point of view. It has been consitlered necessary to pre- serve the cranium of the Giraffe at present in our possession entire ; consequently, we are unable to offer any account of these sinuses from personal examination, which is the less to be regretted, as Prof. Owen has placed 338, Sectional view of ihe 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 -|- ; — * Memoir on the Anatomy of the Nubian Giraffe, .;^ool. Trans, vol. ii. p. 235. f Dr. Cobbold, On the Anatomy of the Giraffe, Annals of Nat. Hist, for June, 1854. Length of cranium - - - - Breadth between orbits - - - Incisive angle to central eminence Length of horns - - - . Di.stance 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 - . - Inches 19 8^ 114 ; 64 04 ^ 3 24 ' 34 2* 154 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 basts of the horns — the length of the jaw — and more particularly the extended vertical di-i- i 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 uniqiie exam|)le 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 tnat 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 {Jig. 328.). As has been al- ready observed, the protuberances are formed in part by the parietal and frontal bones, the RUMINANTIA. 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 columnar 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, severally, half an inch apart, and the interfrontal suture is still distinct throughout its entire length. In regard to the asserted existence of a third horn surm.ounting 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. Ball, 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 Riippell.* 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. cla- phus), — and of the latter, in the Elk (C. alces) 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 " («, Jig. 339.), at which date the deer Fig. 339. Development of the horns hi 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 “spayard.’’ The horn of the fourth year assumes a more complex aspect (d, e), and the summit or “ crown ” of the stem begins to spjread and divide ; at this stage he is styled a “ staggard.” At the fifth year there are five or six branches, and at this period he is termed a “stag.” At and after the sixth and seventh vears 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 Rtippell, 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 he partly raised from the subjacent bone by the easy insertion of the finger-, nail under the margin. I. L 3 518 RUMINANTIA. “pricket” puts forth a simple “dag” or cylindrical shaft {a, iig. 340.), which is slightly bent forward. In the third year the branch- ing commences, and he is said to be a “sorel” (J>). The antlers in the fourth year grow more numerous, and the stem is bifiil 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 (f/) ; 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 se.Kes, but are some- what less branchetl 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 periotlical 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 dispro|)ortionate 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 Sivatheriuni {Jig. 341.) found inthetertiaryclepositsof Northern Front view o f the cranium of the Sivatherium. (From I a model in the Lend. Coll. Surg. Museum.) * India. Living instances of more than a J single pair are seen in the Four-horned Goat and Many-horned Sheep ; also in the Jung- liburka Antelope {A. siibquadricormdus') where the anterior pair are rudimentary, and in the it Chousingha (A. quadricor?iis'), several specie.s of which have been described by authorsfyfg.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 j 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 (7?g. 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. 519 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. Front view o f the cranium, of the Chousingha. (From a specimen in Lend. Coll. Surg. Museum.) ture and outlirre, and in those of the Cahrit 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 (yfg. .343.), Fig. 343, Horns of the Cabrft. (From a specimen in Lend. 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 trunli. — 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 : — D. u. s. c. TOT.vns. Camel - 12 7 4 17 47 Vicugna 12 7 5 12 43 Moschus 13 6 3 14 43 Ked Deer 13 6 4 16 46 Giraffe - 14 5 4 18 48 Gazelle - 13 6 4 14 44 Chousingha - 13 5 4 14 43 Goat 13 6 4 12 42 Sheep 13 G 4 16 46 Os 13 6 5 18 49 In Camelidae the bodies of the vertebrm 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 maramiferous 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 vertebra;) 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 Gwen. The anterior extremity of the “ cen- trum ” is convex {fig. 344.), and the poste- Fig. 344. Section of the cervical vertehree of the Camel, (From Coll. Surg. Museum.) rior concave, but there is no intervertebral 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. {Jig. 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 vertebrie 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- cluB, 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 Bovidm, and still more bulky in Camelidse. The transverse processes of the lumbar ver- tebra 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 Camelidse 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 ^ 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- KUMINANTIA. 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 bone 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 CEgosceridae, Cervidse, and Antelopidas, 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-S[)inal spaces is very striking ; usnally 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 Camelidce 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, loc. cit. 522 RUMINANTIA. intimately united, and, being connected to the humerus by a simple liinge 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 u[)right 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 hones (A.y?g. 34G.), and some have seven, which are disposed in two rows. In the upper may be recognised the os scaphoides (4), os lunare (5), os cuneifurme (6), and os pisiforme (7) ; in the lower the os trwpezoides (8 ) and os magnum (9), and in the Giraffe and Camel the os unci- Jbnne (c, a.). The mctacarpals are represented by a central cfflHHo?! bone (10), and in the Deer- tribe and Antelopes by two additional rudi- mentary s[)lint-like pieces, which are separated from the lower and back part of the former by the intercalation of four ossa sessamoidca. Fig. .347. c ection of the cannon hone. (From Loud. 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 com[)act osseous tissue (d), traversing the hollow eylinder from end to end ; and its duality is further evinced by the bifid character of the distal extremity (a, h), 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 |)achydermata. 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 (y?g.347.f, 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-g times seen behind this joint. The last pair ^ ' are more or less triangular, and their com- billed plantar surfaces form a semicircular, | disc, resembling that of the coffin bone of the v I Horse. In those genera which have super-* I numerary digits, the rudimentary phalanges .i 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 horizontal!}', 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. — Tlie hind and fore limbs are not of equal length, and if the actual extent of the individual bones be added together, the balance v/iil 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 decijihered from personal examination : — * Bridgewater Ti'eatise, “On the Hand,” p. 93. RUMINANTIA. 523 Dromedary " Fore limb. - 62 inches Hind limb. 65 inches Javanese Musk - - 74 »> 11 ,, Eed Deer - - 31" 38 ., Bein Deer - - 32 39^ „ Fallow Deer - 27 34 ., Irish Elk - - 51 60 „ Goat - 19 »> 244 „ Ox - - - - 38 }9 48' „ 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 {Jig. 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 quadratns 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. T\ie\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 {Jig. 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 calcis, and the astragalus. The bones of the tarsus, properly so con- sidered, are five in number, viz., — os calcis, (2) and os astragulus (3), 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 Cervidm 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, 348.). We have already Fia, 348. Bones of the hind limb of 3Toschus. (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 ossa 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 carwostw.— 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 tlie first place vve liave a broad band extending from the fore- part of the neck, and spreading toward the lips and forehead ; this constitutes the viuscidus cu- taneous faciei. Again, it is very strongly marked at the neck, especially in the Sheep ; here it is denominated the m. cutan. co/li. 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 developetl 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. ma.vimus seu 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 princijial 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 MarsupiattX*. Were it not for the constant and involuntary action of the muscle, the torture (to which many animals, particulai ly cattle, are subjected, from the stings and bites of flies and other insects), would become intolerable, and consequently we find in those creatures wdiich 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 the musculus prepu- tiatis seu umbilicus, the superficial orbicularis jialpcbrarum, 2iX\A 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. Theorbicularmuscle of the eyelid {5,fg. 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. Uluscles 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 thetrapezius properlyso calledf 10, 1 l,_/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 portion, which is somewhat shorter and thicker, becoming attached to the spinous Fig. 349. 1, orbicularis oris ; 2, levator labii supevioris ; 3, zygoraaticus ; 4, depressor palp, inferioris ; 4 *, nsonus ■Santorini; 5, orbie. palpebrarum ; 5 *, masseter ; 6, corrugator superc.iliorum ; 7, depressor auncu.ffi ; 8, 8, 8, deltoides ; 9, sterno-niaxillaris ; 10, 11, trapezius; 12, latissimus dorsi ; 13, pectoralis major; 14, obliquus externus ; 15, glutaeus maximus; 16, tensor fascim latm; 17, 18, biceps femoris. * Mercer, On the Structure and Uses of the Panniculus carnosus, Med. Gazette, 1840 — 41, p. 346. RUMINANTIA. 525 Fig. 350. Yiew 0 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, pvriformis ; 22, levat. caudae brevis; 23, lev. caud. longus ; 24, cocc)’geus ; 25, rectus femoris ; 26, vastus externus ; 27, adductor magnus ; 28, semitendinosus ; 29, adduct, tibiae longus ; 30, intertransversales eaudse. 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 vertebras ; its fleshy part is thick and strong, but 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 ligainentum nuchs, 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 proprius of Stubbs, the commu- nis capitis, pectoris et brachii of some, and the deltoides oi otliers (8,8,8,_;7g.349). 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, w’hile 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 michae, 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 sptlen. cervicis. In the 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, w'hich is narrow and insignificant, and a posterior of lai’ge 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 digastriciis to be inserted into the occiput, which Meckel thinks may constitute a rudimentary form of the s[denius 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 conplexus and digastriciis 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- tebrse 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-Iumbalis in man, called the cervicalis descendens — stretches from between the transverse apophyses of several of the lower cervical vertebrae to the oblique and transvei'se 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 develo|>ed in the Camel and Giraffe, presenting in the latter, according to Prof. Owen, four distinct masses, which take their origin “from * Memoir, t. c. 52G RUiMlNANTIA. tlie fourth, fifth, sixth, and seventh cervical vertebras, and are inserted into the manuhrimn sterni and first rib.” In the Sheep the fleshy bundles are very small ; they also arise fi'om the lowermost four cervical vertebrae ; but in tlie Camel they are connected to all the bones of the neck, except the dentata, the posterior scalenus being [)articularly short, and only attached to the last. The /ongus colli and recti have a similar dis[)osition to those of Man. The former is divided into a superficial and deep j)ortion, 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 minor, are com|)aratively 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-mastokleus 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 inuscle 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 Us 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 glaml. 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 pur()ose 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 hone. Fig. 331. indicates the relation of these parts in the sheep. Com- mencing from above, the first |)air — 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 firvonr muscular attach- ment. Their peculiar figure is due to the Fig. 331. presence of two apophyses at the temporal extremity (a a, h 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 cpi-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 cernto- 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-hyals, 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 lo antero-posterior elongation, which feature becomes very manifest in other vertebrata, and more particularly in birds ; it is to tms point that an additional element — the true lingual bone or glosso-hyal — is connected, in IIUMINANTIA. 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 Camelidm the basi-hyal presents no anterior protuberance. The fourth pair or thyro-liyah — 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 adistinct 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 attaohed 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- * See art. Tongue. named families and in the Pachydermata there is likewise a special muscle termed the masto- 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 b_v a tendon close to the inner side of the tendon of the genio-hyoideus ; its fleshy belly has a considerable antero- posterior extent, and diminishes to a very thin edge at its anterior margin. The digas- tiicus 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 digastricus, 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, 1. 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 hyuides one-third of the way down tlie neck ; such displacement, however, is neither required nor indeed compatible witli 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-kyoideus 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 u[)on the os hyoides with due power and extent of con- traction. Its insertion is by a small round tendon.” Tlie muscles of the back and tail present few deviations worthy of remark. The.s/u'«- aVis and lungisshniis 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. Tlie 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. Jeeger 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. Aiiat. (Fr. edit., tom. vi. p.212.) Muscles of the shoulder and fore-lhnh. — The trapezius has already been considered. The levator angulis srapulce {S,fg. 350.) varies little from the ordinary maramiferous type. The rhomhoideus (9) is usually represented by two muscles, r. minor and r. major; the former, sometimes called the suj)erior, arises in the Sheep from the ligamentum nuchas as far forward as the second vertebra of the neck, and the latter, or rhomhoideus inferior, proceeds from the spines of the first two or three dor- sal vertebrae, 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 vertebrae 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 die 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 ot 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 {\2, fig. 349.) is some- what feebly developed in ruminants, but its i attachments are similar to those in Man. The ; pectoralis major ( I'd, Jig. 349) is proportionately \ * Memoir, A c. 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 humerus, 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 communis. 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 ahd. brack, superior ( 1 4, fig. 330.) ; it generally exhibits two points of Jfig. 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, bracbialis intenms ; 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 externus. 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. Ihe external scapular muscles, viz., the. siqmi- Supp. spinatiis fig. .352.) and infra- spinatus (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 inlluminantia and Solipeda smaller than the teres minor or t. internus {2, fig. 35.3). The sub-scapularis (2, 2 fig. 333.) is of large size, and subdivided. The coraco-brachialis (fi,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 bice]3s brachii coraco-radialis or fie.xor cubiti longus (10, yfg. 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 fibro-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 (l,fig. 352, and l\,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 fi om 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 (3, fig. 333.) is the extensor magnus of Bourgelat ; the extensor brevis is the extemor inedius 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, fig. 35.3.). The Ruminantia and Solipeda are generally described as possessing neither supinators nor jyronators, but the above-named author figures in the 0.x a small muscular bundle, which he calls the protiator teres (13, fig. 333.) ; 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 e.vtensor carpi radialis (9, fig. 332.) is single in the Ca- IM M 530 RUMINANTIA. melidae, as in the Horse, rising from the ex ternal condyle and inferior fourth of the hu Fig. 353. Deep layer of muscles of the fore-Umh of the Ox, viewed from within. (Fi'om Guilt.) 1, supra-spinatus ; 2, 2, subscapularis ; 2*, teres minor; 3, teres major ; 4, latissimus dorsi ; 5, ex- tensor cub. longus; G, .anconeus longus; 7, an- con, internus ; 8, coraco-br.achialis ; t), pectoralis major ; 10, biceps brachii ; 11, bracbialis 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 Vne flexor carpi radialis 352.), the tendon of which is connected to the base of the cannon bone behind. The tendons of the extensores digitorum longior (II) and bre- vior (12, flg. 352.) separate in front of the foot, the divisions of the former being inserted into the base of the ultimate bones of the toes, and those of the latter into the distal extremities of the penultimate jihalanges. A muscle corresponding to the abductor poUicis (10) is present, notwithstanding the absence of the thumb, and becomes attached to the inner aspect of the inferior end of the cannon bone. The flexores carpi ulnaris extermis (1.3) and internus {\Q,fig. 352.) are both inserted into the pisiform bone. The tendons of the flexor digitorum sublimis {\o,fig- 352.) and of the flex, digit, ^trofundus jjerfurans remain dis- tinct, tile latter piercing the former as usual. - to be implanted into the base of the distal phalanges of either toe. Muscles of the haunch and hind-limb. — The gluteus maxbnus {lb, 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 latoe {\H,ftg. ,349.) ; the tendon proper to the glutaeus becomes inserted below the trochanter, while that of the tensor is continued on in front of the tibia, perform- ing in some measure the office of a flexor. The biceps femoris or vastus longus of Bourgelat (17, 18, /%. 349.), is a muscle of striking proportions in this order and in solipeds. It originates by two distinct heads, one of which proceeds from the tail ami sacro-sciatic fascia, and the other comes off from the tuberosity of the ischium ; the fibres of both proceed down- ward, and are inserted, the foi'mer chiefly into the head of the tibia, and the latter into the general aponeurotic covering of the leg. In consequence of the posterior border of the front division overlapping the ischiatic por- tion, there results a well marked groove or raphe, forming a characteristic feature exter- nally on the skin as when the muscle is in ac- tion; this is better seen in the Horse. The ar- li rangements of the iliacus internus {fit, fig- 350.), i' glutceus medius (18), and minimus (19), and ppriforniis, are similar to those in Man, differ- ing mainly in proportion, the last named being particularly small ; the same observation applies more or less to the obturator externus and internus, the genielli, quadratus femoris, ^vasti and adductores, the two groups of muscles !i comitrehended under the latter titles being chiefly interesting on account of their great ' size and strength. ■ Having already extended our myologica! ' descriptions beyond the prescribed limits, we conclude this part of our subject by observing that the muscles of the hind leg resemble those of Solipeda so closely as scarcely to demand a separate notice, while those acting upon the digits have the same general dis- position as in the fore limb. Integumentary System. — Under this head we proceed to indicate very briefly certain peculiarities of the hair, and more particularly the elastic cushion of the sole of the foot, and the remarkable protuberances situated on the back of the Camel. While the growth and condition of thecuti- cular layer of the skin in the different classes 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 RUMINANTIA. 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 vertebrm. 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 Camelidffi 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 tw'o 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 imraoveably together ; while at the same time it is particularly worthy of remark, that the hoofs are inerelv 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 Iluminantia 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 Cervidm 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 ordinaiy 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 j and, in order Fig. 334'. Foot of the Sheep. M M 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. 35-t. represents the position and dimensions of this organ in the Sheep. According to Sir Charles Bell there is yet another intention in tliis 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 Systeji. — Buccal Cavity. — The lining mucous membrane of the oral cavity is very rough, being covered throughout with very prominent pajiillas. 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 papillce 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 rugae 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 rugte are situated fiirther back, and are more fully marked, par- ticularly in those which swallow bulky and comparatively rough morsels, as in the ru- minants and solipeds.”f The oral roof of the Giraffe is m.arked 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 papillm attain their greatest size in the region of the cheek opposite the true mo- lars. Ill 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. t 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 papilla: 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 nuchas, rendering such a motion almost effortless. In CEgosceridse, Bovidte, and Cervidae 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, j 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 cemeiitum, 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 office^ 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 .'). These processes villous chorion universally adherent to the are highly vascular, and exhibit eminences uterine walls, these processes are not pre- and follicular depressions for the implantation of the tufted filaments of the cotyledons or * Memoir, ?. c. p. 241. UTERUS AND ITS APPENDAGES. 5-io sent. In the typical species, numerous trans- verse and prominent ruga3 are developed internally at the lower part of the uterine cavity ; they are somewhat irregularly dis- posed in parallel rows, and are more crow'deil together towards the os thicce, where they are split up, as it were, into fine longitudinal lamellae, imparting to the os, when viewed from below, a peculiar radiated aspect. This latter feature is very striking in the Camels and in the Giraffe. The vaginal mucous membrane («) is smooth throughout, and contracted inferiorlj' at the external orifice. In horned Ruminantia the clitoris is placed just within the vulv'j, but external to the vaginal outlet in the Camelida3 (Owen). Preputial follicles also occur in the female ruminant as well as Cowperian glands, which are situated near the root of the clitoris. In the gravid uterus of the typical species, the fcetal membranes — consisting of tlie chorion (1, Jig, 367.), amnion, and allantois — Fig. 367. Portion of the chorion of a Cow, showing the cotyledons. (.From Gurlt.) are connected to the walls of the cavity bj' numerous small placentulce or cotyledons (2, Jig. 367.), which embrace and dove-tail with a corresponding series of processes developed from the uterus. The cotyledons are pro- ductions of the chorion, and have an oval or rounded shape, more or less compressed, the exposed surface being usually cup-shaped ; after the expulsion of the fcetus these bodies come away with the membranes, and the uterine protuberances diminish considerably in size. In the Sheep aiul Cow the number of the placentulas varies from about seventy to a hundred. Like the chorion, the amnion is highly vascular. The allantois exists in the form of a closed sac, and only partially covers the amnion. In the Cameline ru- minants the ovum is retained in situ by a universally adherent villous chorion, such as is found in Solipeda and Pachyderraata. The mammary glands are situated in the inguinal region between the thighs ; the teats are four in number, except in Qigosceridae, where there are only two. Rudimentary Supp. nipples are occasionallv found in the male on either side of the scrotum ; in the Horse they exist on the sheath of the penis. Bibliogr.vphy. — Ray, J., S3'nop. Method. Ani- mal. Quadruped., &c., 8vo., 1G83. Linnaeus, Sj-stema Naturae, 1736 — 1738. Pennant, Hist, of (Quadru- peds, 1771. Pallas, Spieilegia Zoologies, 17(J7 — 1780. Daubenton et Buffon, Nat. Hist. 1748. lUi- ger, Prodromus S_vst. Mammal., &c., 1811. Azara, Don. F., Quadruped, de Paragu.a}-, 8vo., 1801. Lichtenstein, H., Magazin der Gesellschaft Natiirf. Freunde zer Berlin, 1812. Desmarest, IMammologie, 1822. Ruffles, Sir T. F. (quoted in), Linn. Trans., vol. xiii. 1822. Meckel, J. F., Sj'st. der Vergleicli. Anat. 1821, Fr. edit, par Reister et Sanson, 1829. Pander und D' Alton, Die SUelete der Wiederkatier, 1823. Riippell, E., Reise in Ndrdliehen Afrika, 1828. Gurlt, E F., Anat. Abbild. der Haus-SUuge- Thiere, 1824 — 1833. Cuvier, F., Hist. Nat. des Mammif. ; Cuvier, G., Lecons d’Anat. Comp., 2‘'<= edit., par M. Dume'ril, 1835 ; Ossemens Fossiles, tom. ii., 1821—1824. Wagner, R., Lehrbuch der Vergleicli. An.at. 1835. Ogilby, On the IIollow'- horned Ruminants, Zool. Trans., vol. ii., 1836 ; also, various art. in Penny C^xlopied. Smith, Col. H., in Griffith’s edit, of Cuvier’s Animal Kingdom, vol. V., 1827 — 1835. Blainrille, Osteographia, 1841 — 18.55. Owen, Anat. of the Giraffe, Zool. Trans., vol. ii., 1838, and vol. iii., 1839 ; also, numerous contrib. in the Pln-siological Series of Hunterian Catalogue, and in his Odontographv, &c. Zaglas, J., On the Muscular Structure of the Tongue (in rvhich he refers more particularlv to the anatomy of this organ in Ruminantia'), Goodsir’s Annals of Anat. and Physiol. 1850 — 1852. Franz Muller und C. U'edl, Beitrage zur Anat. des Zw'eibuckeligen Kamelees, Denkschrift. der Kaiserlieh. Acad, der Wissenschaft. 1852. Bendz, H. C. B., Icon. anat. mammal, domestic, fasic. osteog., 1850. T. Spencer Cobbold. UTERUS AND ITS APPENDAGES. — The reproductive organs in woman consist of the Ovaries, Fallopian Tubes or Oviducts, Uterus, Vagina, and Vulva. These are com- monly subdivided into the formative and copu- lative organs. To the first division belong the ovaries. Fallopian tubes, and uterus ; to the second the vidva; while the vagina, on ac- count of its offices in copulation and in labour, may be regarded as common to both. This division nearly corresponds with an- other and more artificial arrangement, by which these parts are subdivided into the internal and external generative organs; those being regarded as internal which are protected within the body and concealed from view, while those which can be easily seen are termed external : the line of demarcation being here at the entrance to the vagina. Of the several organs just enumerated, the uterus has doubtless, on many accounts, prior claim to attention. It is the largest of these pai ts. It is that which contributes the greatest amount of material to the new organism which it contains and protects. It is that part in which alone a direct connection of attachment subsists between the fruit and the parent. Its functions, so far as they con- tribute to each individual act of reproduction, are exercised for much longer periods of time than those of any other portion of the gene- rative apparatus. It exerts a powerlul refle.x N N 540 UTERUS AND ITS APPENDAGES. Fig. 368. Uterus and appendages of an adult virgin, posterior aspect. {Ad iVaf.) a, uterus; Ih, ovary; cc, Fallopian tube or oviduct; dil, fimbriated extremity or infundibulum of the tube ; ee, terminal bulb of the duct of lUiiller ; f'f, portion of broad ligament and blood-vessels ; g, vaginal portion of cervix uteri ; li, os uteri ex- teriinin ; i, anterior and /, posterior wall of vagina; III, ligameulum ovarii ; n, tubo-ovarian ligament. influence, especially tlnring pregnancy, upon other parts and organs. The diseases and accidents to which it is liable arc more nu- merous, and are attended by greater danger to life than those which tiflect any other portions of these structures, whilst its several morbid states, as well as its natural condition, may be ascertained during life with a degree of precision which virtually removes the ute- rus from the category of internal parts. But it is only in a practical or obstetric point of view that the uterus can be regariled as the most ini[)ortant of the generative organs. Physiologically considered, it is by no means cntitletl to the foremost place ; for although the presence of the uterus is neces- sary to the completion of the generative act in its regular course, yet reproduction to a certain extent may be accomplished without it. The uterus is necessary to reproduction, first, as aftbrding the only channel by which the seminal fluiil can obtain access to the ovum; and next, as constituting, together with the vagina, the only natural passage for the exit of the fully matured ovum, which re- quires this contractile organ to effect its expulsion by that passage : such expulsion not being essential to the generative act be- cause the foetus may be extracted by the Cae- sarean section v\ithout necessary loss of life either of the parent or offspring, while other parts — the Fallopian tubes for example — may, to a certain extent, perform the offices of a uterus in all that relates to the protection and nutrition of the ovum. Moreover, the entire removal of the uterus may have no other effect upon the individual than that of pre- venting impregnation ami menstruation by the simple abstraction of the parts necessary thereto. On the other hand, the ovary, tiiough con- stituting only a small portion of the re|>ro- ductive organ.s, is nevertheless that part to which all the rest are subservient. It is the organ wliich furnishes the generative element essential to the reproductive act. It is that part which, in a great measure, regulates the growth of the body, and determines the dis- tinctive characters of the sex. It is the organ upon the presence of which depends the sexual passion ami the process of menstru- ation ; whose congenital deficiency is indicated by the absence externally of all signs of a secondary sexual character ; whose artificial removal entirely unse.xes the individual, and the decline of whose functional activity, as age advances, is the cause of the generative faculty being lost in the female long before the ordinary term of life has expired, and at Fig. 308. 547 OVARY — (Normal Anatomy). a much earlier period than that at which the power of procreation ceases in the othei sex. In a physiological sense, theretore, the uterus, as well as every other part of the generative apparatus, must be regarded as an appendage of the ovary ; and the title “ Ute- rus and its Appendages” is employed, in ac- cordance with ordinary usage only, as the heading of this Article, in which it is pro- posed to consider the structure and func- tions of the entire female generative organs as they exist in Man.* OVARY. Normal Anatomy. (Syn. Ovarium, Testis Afuhebns, Lat. ; Ovaja, Ital. ; Ovaire, Fr. ; Eierstoclc, Germ. ; Eijerstok, Dutch.) The ovaries (7%. 368. h,b) constitute two follicular glands appropriated to the formation of the female generative element. They are perfectly closed, resembling in this respect the ductless glands. Each, however, is furnished with its proper excretory duct, {fig. 368. c, c) between which and the gland a temporary connection is established, at certain intervals, during that period of life over which the re- productive faculty extends. Form. — The ovary is not usually fully de- veloped until some time after the establish- ment of puberty. It is then of an oval form Fig. 369. c Ovary of a young adult virgin before the surface has become scarred by repeated discharges oj ova. {Ad Nat.) a, distal, and h, proximal extremity; c, superior, and d, inferior border. In the centre is laid open a Graafian follicle from which an ovum had recently escaped by spontaneous rupture. (fig. 368. b, and fig. 369.), flattened on its i sides, and somewhat resembling the testis in 1 figure, but rarelv or never, in a state of health, i attaining to the full size of that organ. The following division may be made of its I * For the comparative anatomy, as well as for the ' general treatment of the subject of generation, the i reader is referred to the articles, Generation, ORGANS OF; Generation; and to those descrip- tive of the different classes and orders of the animal kingdom throughout this Cyclopiedia. The oc- j casional introduction here of illustrations from com- . parative anatomj^ and physiology is employed for I the purpose of elucidating those questions which j cannot be clearly explained by observations made I only upon the human subject. 1 i superficies : viz., into two sides, situated anteriorly and posteriorly with regard to the body ; two extremities, outer and inner ; and two borders, superior and inferior. Of the two sides, that which is directed anteriorly (fig. 370. e) is both shorter and less Fig. 370. Vertical section of ovary. {Ad Nat.) The posterior surface,/", more rounded than the anterior, e; at /i are numerous blood-vessels divided ; qq. Graafian vesicles ; d, place of entrance of vessels between the layers of the broad ligament. convex than the posterior, which is generally rounded and gibbous (fig. 370. f). In this respect the ovary resembles the uterus, whose posterior surface is alwaj's more rounded than the anterior; by attention to this [)ecu- liarity the right ovary may be readily distin- guished from the left after these organs have been detached from the uterus. Of the two extremities, the outer or distal (/?g.369.and_,%. 372. a) is usually rounded and bulbous, whilst the inner(/'g4'. 369.and372. b) becomes gradually attenuated until its outline is merged in the proper ligament (fig. 368. ?u) by which the ovary is attached to the uterus. The upper and lower borders also differ from each other. The former (fig. 369. c) is con- vex, and forms a segment of a circle, whose diameter is continually diminishing as age advances. The latter is straight or slightly concave, constituting the base of the ovai/', or the line by which it is connected to the posterior duplicature of the broad ligament (figs. 369. and 370. d). (Dimensions and Weight. — The ovary of a healthy adult measures from 1" to 2" in length, from Q"' to 12"' in depth or perpen- dicular diameter, and from 3'" to 6"' in wndth or transverse diameter. These dimensions, which vary considerably in different individuals, exhibit a much wider range when the observations are extended to different epochs of life. The organ is then found to undergo far more remarkable changes in bulk and figure than are observable in the corresponding male organ. The following table, giving the highest, lowest, and mean dimensions of twelve healthy ovaries, taken indiscriminately from women in various conditions during the period of fer- tility, will serve to exemplify the first of these variations : — • N N 2 5 is UTERUS AND ITS APPENDAGES. Longitudinal. Perpendicular. Transverse. Highest 2" 1" 1'" 6'" Lowest 1" 6'" 3'" Mean 1" 4"' 9'" 44"' Another and more accurate method of esti- mating the l)ulk of the ovary consists in weighing. The following are the extreme and mean weights of five ovaries taken from healthy adults : viz., greatest wciglit, 135 grs. ; least, (iO grs. ; mean ( of five examples), 87 grs. On comparison of these results with Krause’s estimate of the weight of the testis, which gives the mean weight of tlie male organ, also in five instances, as 354'4 grs.’’', it appears tliat the ovary, though furnishing the larger portion of the generative element in the act of repro- duction, has an average bulk of less than one quarter of that of the corresponding male gland. Position and Connections. — The ovary is so intimately' connected with the uterus, in whose changes of position, both normal and ab- normal, it necessarily takes part, that it can- not be said to have any fixed or definite seat. It is most commonly found lying somewhat deeply in the lateral and posterior part of the cavity of the true pelvis, concealed from view by the small intestines, and in jiart covered hv the Eallopian tube of the same side. Rela- tively to the uterus, the ovary is placed on either side of that organ, at a distance varying from 4"' to 18'", and behind and a little be- low the level of the point of entrance of the Fallopian tubes (fig. 368.). Each ovary is invested by a layer of perito- neum derived from the posterior lamina of the broad ligament, to which the ovary is thus attached by a kind of mesentery. Besides this indirect connection with the uterus, through the intervention of the broad ligament, the ovary has also another and more direct attachment by the aid of its own proper ligament (ligamentum ccarii), which serves to bind it more securely to the uterus. (Pig. 368. ?w.) The ovary is further connected at its outer extremity to the mouth of the Fallopian tube by one of the processes of the pavilion, which serves to kee[) the organ always in close proximity to its excretory duct (fig. 368. 7i). The distance which intervenes between the ovary and the uterus varies considerably on each side, not only in different individuals, but also in the same subject, where it is very rarely found to be equal ; the right ovary, so far as my observations have gone, being farther removed than the left in the proportion of nine out of twelve instances. During pregnancy, the ovary suffers fre- quent changes of position. As the uterus ex- pands, it carries the ovary along with it into * See art. Testis, Vol. IV. p- 976. the abdominal cavity, at the same time the relative situation of these parts is mate- rially altered, the fundus uteri gradually ex- panding and rising above the former level of the ovaries, whilst the latter appear to be bound down more closely to the side of the utei'us, until at term their position is usually found to be below the centre of that organ. Component Parts. — The ovary is com- posed of, 1st, protecting parts, or tunics ; 2nd, a parenchyma, or stroma, in which are imbedded ; 3rd, the proper secreting struc- tures, in the form of closed sacs or vesicles, containing the ova ; 4th, vessels and nerves. 1. 21ie Protccthig Parts or 2\mics. — These are two in number, and corres|)ond precisely, both in structure and derivation, with the analogous coverings of the testis. 'Phe peritoneal covering (fig. 371. a) consti- tutes the outermost of these coats, and consists of thelayerof peritoneum derived from thepos- terior lamina of the broad ligament, which serves to connect the ovary with the parts adjacent. Except at its base, the ovary is so closely in- vested by this peritoneal lamina, that no ef- fort with the scal[)el will suffice to detach it from the tunic beneath. This intimate union, however, of the two coats ceases at the base of the oval'}’, where a white, irregular, and somewhat elevated line is observed on either side, extending in a horizontal direction, and rising higlier on the anterior than on the pos- terior surface of the gland. In its intimate texture, this covering of the ovary differs in no respect from the peritoneum covering the viscera generally. ,, The tunica albuginea, or tunica propria, (fig. | 371.BI!) constitutes the special or proper cover- ing of the ovary. It serves to give form and soli- J dity to the organ, and to protect the ovisacs j and ova from injury. This coat has a nearly J uniform thickness of , and forms a complete \ investment for the ovary, except at its lower j border, where the fibres are either very thinly i scattered and interlaced, or are altogether wanting, leaving a longitudinal space, termed ' the hilum or vascular fissure, by which the ' vessels and nerves enter the organ. This space measures 3"' — 4"' in width, and extends , along the entire base of the ovary. The tunica albuginea has been commonly i regarded as a more condensed portion of the I stroma, or parenchyma, of the ovary ; but ' from this it is readily distinguished, not only , by its clear white colour, and dense and almost cartilaginous hardness, but also by its micro- scopic characters. On account of its extreme i toughness, this tunic is not very easily sepa- 1 ruble into fragments sufficiently minute fori microscopic examination. But when small portions have been so obtained, the margmsoti the fragments exhibit numerous close-lying and irregularly arranged fibres of developed connective tissue, projecting from a dense, .■ structureless mati'ix interspersed with gra- ■ nules, which serves to connect the fibres to- gether, and to which apparently is due, in a|M great measure, the peculiar toughness of this ■ membrane, while its remarkable whiteness is ■ OVARY — (Normal Anatomy). 549 explained by the much smaller number of blood-vessels that it contains, as compared with the general parenchyma of the ovarj'. The tunica albuginea, therefore, is not merely a more condensed form of the ovarian stroma, but appears to result from a development of tissues which exist in the stroma in an ele- mentary or embryonic form, as well as from a more close conjunction and blending of those tissues. 2. ThcParencJn/manr Sb'omaXJig. 371.C,and Jig. 372. s) constitutes tlie proper tissue of the ovary. It lies immediately beneath the tunica albuginea, and fills up the whole of the inter- mediate space between the ovisacs, to which it acts as a germ bed, protecting the ova from injury, and servingfor the conveyance of blood- vessels to the ovisacs. This tissue is some- times of a pale-pink, but more often of a bright-red colour, from the large number of blood-vessels which it contains, whose ar- rangement proceeding from within, and radi- ating outwardly in all directions, gives to this tissue, when viewed by the naked eye or by Fig. 371. Ovary enlarged four diameters. {After Coste.') Dissected to shew, A, peritoneum; b, tunica albuginea; c, stroma; oddd, Graafian follicles in various stages of growth; EE, outer coat of the follicle (tunic of the ovisac) ; ff, inner coat of the follicle (ovisac) ; ggg, epithelial hnmg (meinbrana granulosa) ; hh, ovum and cumulus ; i, orifice by which the follicle has discharged an ovum; K, Fallopian tube; L, fimbriae; Ji, posterior ala of broad ligament or mesentery of ovary; n, tubo-ovarian ligament ; o, ligamentum ovarii. N N 3 350 UTERUS AND ITS APPENDAGES. a common lens, the appearance of being formed into bundles or laminae. The microscope, however, serves to resolve this tissue into its true elements. When so examined, the stroma is found to be composed mainly of blood-vessels, to which a great part of its strength and toughness is due, the in- termediate spaces being filled up by a fibrous structure not separable into bundles, like ordinary connective tissue, and having no dis- tinct fibrillar arrangement, its chief elements being single white fibres of ordinary connective tissue, numerous fusiform embryonic fibres,and elli[)tical and round cells or granules, the whole being coherent and strongly united together. 3. The (rranfian Vesicles. FoUicidi ovarii, s. Graafiani, s. Ovisacci. — When the substance of a healthy ovary is divided by a clean incision, if the sniiject be not too advanced in life, the section will be found to have included several vesicles varying in diameter from F" down to sacculi of microscopic minuteness. These Fig. 372. 1 joiujitud'mal section of adult ovary . (^Ad Nat.) a, distal ; h, proximal end ; s, stroma ; jr, Graafian follicles of the ordinary size before enlargement; h, stellate remains of follicles which have burst and shrunk after discharging their ova. vesicles, familiarly known as the ova of De Graaf, although the credit of antecedent ob- servation is certainly due both to Vesalius * and Fallopius f , are variously distributed through the ovary according to the age of the indiviclual. In infants and young subjects, the ovisacs are found only at the periphery of the organ, where they form a thick rind, the inte- rior of the ovary being occupied only by blootl- vessels and stroma. But after puberty the division into a cortical and central part be- comes less distinct, the ovisacs becoming buried deeper in the stroma, so that occasionally, in making sections of the part, they are encoun- tered as deep as the base of the organ. They are always, however, most numerous near the .surface. The number of developed vesicles contained in each ovary, and visible to the naked eye, varies considerably in different subjects. Up * De Corporis humani Fabrica, lib. v. cap. xv. p. 459. f Obs. .\iiat.. Op. omnia, IGOG, vol. i. p. lOG. to a very recent date it appears to have been assumed that their number was limited. They were usually estimated at 12to 20in each ovary; anil it was generally supposed that, when these were exhausted by child-bearing and miscar- riage, the power of procreation of necessity ceased. More recent and careful observation, however, has shown that the number of vesi- cles in each ovary amounts in healthy organs to 30,30, 100, or even 200;, whilst in very young subjects their numbers exceed all power of accurate computation. The vesicles are mo.st easily displayed in the adult ovary by making a perpendicular section through the organ in the direction of its longer axis. In this way the largest num- ber will have been divided by one incision ; and such a section, as in fig. 372., will often suf- fice to exhibit 8 to 12 vesicles of different sizes. On submitting the section, however, to the microscope, others of a smaller size, which had previously escaped attention, will be brought into view ; and in continuing the incisions in various directions, fresh vesicles will be laid open of various sizes and in dif- ferent stages of development. If the ovary of an infant be selected for observation, the organ should previously have been hardened by maceration for several days in spirit. A clean section is thus easily obtained by a sharp knife; and if this be examined by a 1-inch ob- ject glass, the little spherical ova, coagulated by the action of the spirit, will be readily seen, each one lying in its proper ovisac, by which it is immediately surrounded, and the whole so closely set and so numerous that a single sec- tion suffices to display several hundred of them at one view {fig- 373.). Fig. 373. Section of part of the ovary of an infant, aged '20 months. The central portion consists of stroma and blood-vessels only. The lighter peripheral part is composed entirely of close-set ovisacs, conlaining ova of variotts sizes. (^Ad Nat. x 16 diam.) The Graafian follicle, when not subjected to [iressure from surrounding parts, or from .ad- jacent vesicles, is spherical or oval in form, { fig. 371. DD, and fig. 372. g) and consists of cer- tain tunics and contents. The number and composition of its coats have been variously described by recent observers ; and upon tins subject a difference of views would be of coin- paratively little importance, if upon a right solution of this question did not depend the clear comprehension of those changes which occur in the Graafian follicle during preg- 551 OVARY — (Normal Anatomv). nancv, and which result in the formation ol the body termed tlie corptis luteum. Without entering upon the question of the number of lamiiiEe into which the walls of a Graafian follicle may be split by skilful mani- pulation, it will suffice to consider those only as distinct membranes or coats, which exhi- bit obvious differences of structure and rela- tionship, during the various phases of develop- ment and decay which the follicle undergoes from its first formation to its final disapjiear- ance. In this view the walls of the Graafian follicle must be regarded as being composed of three membranes ; and indeed but for the importance attached to the use of the third or innermost of these, which in any case is hardly more than a thin layer of granules, it would have sufficed if the coats of the vesicles had been enumerated as two only. The external fibrous or vascular coat {fig- .37-i. a. Jig. 371 . e) constitutes the tunic of the ovisac of Barry, the tunica fibrosa, S. theca fol- liculi of Baer. It forms no portion of the ori- ginal ovisac, but is a superadded part, derived from the parenchyma of the ovary. This coat closely embraces the ovisac, and partakes Fig. 37-I. Graafian vesicle of the rabbit x iW diameters. {After Barry.') a, outer coat or tunic of the ovisac ; b, ovisac ; c, epithelial lining or membrana granulosa, a por- tion of which has been removed in order to display dd, retinacula (here too distinctl)' marked) ; e, tunica granulosa of Barry immediately surrounding the ovum, consisting of, f, zona pellucida, within which is the 3'elk and germinal vesicle and macula. in its spherical figure ; it carries numerous blood-vessels, which pass from the ovarian stroma to become expanded in a vascular net- work over its walls (y%. 371. d). Examined by the microscope, this membrane is seen to be highly vascular. It is composed of a fine membrane, containing few fibres, but everywhere abundantly studded with oval nuclei, visible without the aid of acetic acid, and probably, in part at least, due to the pre- sence of so many blood-vessels in its tissue. This coat contains no oil globules. Its chief use appears to be to give increased support and protection to the true ovisac which it sur- rounds, and to convey blood-vessels from the ovary for its nutrition, and for the supply of the fluids which the ovisac contains. The second or internal coat, as it is com- monly termed, of the Graafian follicle is the ovisac itself. It constitutes at first an inde- pendent structure; but receiving afterwartls the before mentioned investment from the ovarian |)arenchyma, the tw'o coats unite to form the Graafian follicle. The ovisac is F'tg. .375. Structure of ovisac. {Ad Aat. x 350.) composed of embryonic fibres of connective tissue (fig. 375. a), of rounded cells or graiuiles, 6; and of a large proportion of minute oil globules, c. The embryonic fibre-cells lie [)arallel with each other, and together with the granules form the bulk of tlie tissue in nearly equal proportions. The oil drops are very numerous; and after the preparation has been under examination for some time they are seen to float uj) to the surface of the drop of water in which it is placed, and to collect upon the under side of the glass disc used for covering it. In addition tothese there is found a small quan- tity of developed fibres of connective tissue, which appear to give firmness to the whole. The Graafian follicle thus composed, contains, in close contact with its inner wall, a stratum of nucleated cells, forming an epithelial lining, termed the membrana granulosa (fig. 37-1. c, fig. 37 1 . g). The cells or granules which give a name to this membrane are so lightly held to- gether that it has beeji doubteil whether the stra- tum which they form is really entitled to the denomination of amernbrane. Nevertheless this structure appears to play an important part in regard to the ovum, which is always found lodged within a portion of it. At the com- mencement of the formation of the ovisac, ac- cording to Dr. Martin Barrj', these peculiar elliptical nucleated cells or granules are nearly equally difiiised through the fluid which it con- tains, the ovum lying in their centre. But about the time at which the ovisac unites with its covering or tunic to form the Graafian fol- licle, these granules are found to have become separated into little groups, leaving interspaces filled by fluid. Further, as this se[)aratiori ad- vances, the granules arrange themselves in such a manner as to constitute three distinct struc- tures. The principal portion collects upon the inner surface of the ovisac forming the mem- brana granulosa just described (fig. 374. c). A second portion becomes aggregated upon and around the ovum, taking its form and constituting a special investment for it. This is the tunica granulosa of Barry (fig. 374. e). A third portion collects to form a structure composed of a central mass in which the ovum with its tunica granulosa is imbedded, corresponding with the cumulus (fig. 371. h,h) of Baer, and of certain cortls or flattened bands, from two to four in number, which pass off from the central mass outwards, to become united with the layer of granules lining the follicle. These radiating bands or cords arc termed by Barry the reL'inacula, (Jig. 371. dd) N x 4 55:2 UTERUS AND ITS APPENDAGES. from tlieir supposed office in suspending the ovum, and retaining it in its proper situation in the Graafian follicle. That the retinacula, however, are not essen- tial structures is proved by the fact that they are wantiugin maiiyofthe Mammalia as well as in Man. They have been observetl chiefly in the Roilentia and Ruminantia, whei'c their form aiul nuinbei' are subject to considerable varia- tion. 'file .subjoined figure e.vhibits the ovum 370. Ocam of rahtnt siirrounihd by the tunica yranulosa and purtiuns o f retinacula. After Coste.') surrounded by the layer of granules which constitutes the /miica granulosa, and externally to this the radiating baiuls or retinacula, the whole of those ]>arts, external to the ovum, being composed of nucleated celbs. Besides these structures, the Graafian follicle contains a pellucid albuminous fluid, of a sliglitly yellowish colour, partially coagulable by heat. In this fluid float numerous grannies similar to those of which the parts just ile- scribed are formed, together with a varying quantity of oil-like globules. Lastly, in the midst of the granules at an early ]ieriod, and subsequently in that more de- finite arrangement of them which constitutes the tunica granulosa, is contained the ovum {Jig. 374. f, and Jig. 37G.), a full description of which is given in the article umler that title. 4. Vessels and Nerves. — The ovary de- rives its supply of blood chiefly from the ovarian (spermatic), but in part also from the utei ine arteries. So free, indeed, is the com- munication between these vessels, that the organ may be equally well injected from either source. The communication is effected chiefly by means of a branch of the ovarian artery, which passes inwards to inosculate with a ter- minal branch of tlie uterine artery, this anas- tomotic branch being occasionally so large as to constitute the [triucipal source of siqtply of the ovary. The terminal vessels are con- ducted to the lower border of the ovary be- tween the folds of the posterior duplicature of the broad ligament, where they lie in parallel lines, and are readily distinguished by their tortuous or spiral form. Having en- tered the base of the organ, they spread out into those numerous ramifications which pene- trate every part of the ovarian stroma, and give to this structure its pecidiar fibrous as- pect. From their extreme branches the blood is returned by the veins, which pass to the base of the organ, where they are very numerous (Jig. SfO. li). They form, near the ovary and between the folds of the broad ligament, a |)lexu.s termed the ovarian or pampiniform plexus, (Jig. 369. d) the vessels of which com- municate also with the uterine plexus. Valves are found in the ovarian veins only in exceptional cases. The ovary derives its nerves from the renal and inferior aortic [ilexuses.* The nerves enter the organ along with the blood-vessels. Functions of the Ovary. The ovary is to the female what the testis is to the male — the germ-|)reparing organ, the [lart in which is formed the female generative element, and therefore the essential portion of the entire sexual ap|)aratus. To it all other structures may be regarded as accessory or siqiei'added ; for in by far the largest proportion of the animal kingdom they are either found in a rudimentary state, or else have no existence. But not only is the ovary the organ in which the formation and evolution of the germ take place ; its offices farther extend to the separa- tion anil expulsion of the ova, when they have reached such a state of maturity as will render them susceptible of inqiregnation. This process, commonly termed ovulation, takes [ilace spontaneously, and without the intervention of the male, which is not nece.s- sary thereto. All animals possessing an ovary are subject to this law ; and Man constitutes no exception to the rule. But the functions of the ovary are exercised only during a cer- tain [leriod of life. The ova, which are formed at or near the time of birth, and sometimes before that event, are not called into activity until the body of the parent is sufficiently developed, to suffer the parturient act without destruction or serious detriment to its own tissues, such as would be incompatible with the continuance of its own life, and such as is witnessed in those lower tribes where the whole of the vital energies of the parent are exhausted by one effbrt of reproduction, or its tissues are even disrupted by the process which produces its kind. But long before the time arrives at which the generative faculty is capable of being fully exercised, it is probable that many of the ova which were first formed have perished, their place being continually supplied by new' formations, j- Their numbers, however, are so great that, if only the one thousandth part of those originally contained * Snow Beck, Phil. Trans. 1846, part ii. f Barr)', Phil. Trans. 1838, part ii. p. 319. Dr. Kitchie, Med. Gaz., vuls. xxxiii., xxxiv. OVARY — (Functions). 55S in the ovary remain, and no new ones are superadded, there will still be more than sufficient for all the purposes of reproduction. But as the functional activity of the ovary, so far as relates to the emission of ova in a state fit for impregnation, is restrained on the one side until the arrival of a certain stage of development of the parent, so on the other a period equally arrives, after which this power of producing and emitting ova altogether fails; and it is plain that both these restrictions con- tribute to one and the same end, the limita- tion, namely, of the office of reproduction to that period of life in which the vital energies of the producing body, having attained to full perfection, remain still unimpaired, so that the qualities of healtli and vigour in the parent may be transmitted undiminished to the oti- spring. From this it results that the ovary in Man, as well as in the Mammalia generally, has three noticeable periods : the first, of prepara- tion ; the second, of activity; and the third, of decay : and these correspond respectively with the periods of infancy and childhood, ot youth and prime, and of decline and old age. The condition of the ovary at each of these epochs will be traced ; but the middle period is obviously that to which the chief interest attaches. During certain portions of this epoch, and in some instances through more or less of its whole extent, the ovary is employed in ripen- ing and emitting ova. In this respect, how- ever, greater variation is perceptible in dif- ferent species than in any other particular. But in all alike this one circumstance is ob- servable, namely, that the emission of ova is a periodic occurrence. Now the periods of emission of ova may so occur as to make the times of parturition co- incident with the returns of those seasons which are most favourable for the rearing of the young. In such cases the capacity for impregnation may be limited to one period of the year, the ova being ripened and emitted only at that time. The roe affords an inter- esting example of this. The doubts which have been sometimes entertained as to the precise time at which the roe becomes impreg- nated have now been settled by the recent very careful researches of Bischoff*, who has proved that this occurs at the end of July and during the month of August, and that it is only then that the ovaries of the female con- tain ripe ova, and the testes of the male ripe semen. At other times these are not to be found ; hence it follows that in this animal im- pregnation is impossible at all other seasons. But in many animals the periods of ripening and discharge of the ova recur with much greater frequency ; and probably climate, food, domestic care and the like, exercise a certain degree of influence in modifying the returns of these periods. In the human female the same periodicity is observable; and it is now rendered in the high- est degree probable that in her case the times of ripening and generally of the discharge of the ova are coincident with the times of menstruation *, just as it has been proved beyond dispute that in other Mammalia the same process accompanies that more obvious condition of aptitude and desire for sexual intercourse to which the terms oestrus and rut are applied. A periodical maturation, therefore, of ova, accompanied by dehiscence of the ovicapsules and discharge of their contents, may be said to constitute the principal offices of the ovary during the prime of life. But notwithstanding that these processes are periodically performed, the ovary cannot at any time be said to be in a condition of perfect rest, except under cir- cumstances which will be presently noted; for whilst some ovisacs may be observed to be advancing and jireparing to emit ova, others may be seen receding or becoming obliterated. The climax, however, of each serial process is the dehiscence or rupture of one or more follicles. Upon this the whole force of the ovary is, as it were, for the time concentrated. This event being terminated, the activity of the ovary passes away as regards that parti- cular follicle. Enough, however, of vital energy remains in the now useless part to suf- fice for the healing of the wound, and the closing and obliteration of the cavity left after the escape of the ovum. But the blood gra- dually deserts the walls of the previously congested ovisac, the distended vessels in its neighbourhood shrink and become obliterated, and the action is transferred to another set of follicles, one or more of which pass through a similar order of changes. Two circumstances, however, arrest for a time this process. The one is the occurrence of utero-gestation, the other the performance of lactation ; and although occasional excep- tions may be observed, yet so far as this ques- tion has been examined, the evidence collected favours the belief, that in pregnant women and in those who suckle, no ova are emitted during the continuance of either of these processes. j- This view also, so far as relates to lactation, receives support from the well-knowm circum- stance that a considerable degree of immunity from impregnation occurs during the conti- nuance of lactation, a circumstance easily ex- pldined upon the supposition that at that time usually no ova are matured or emitted. It will now be necessary to trace in detail the process of ovulation, so far as regards the structures concerned in that process which properly belong to the ovary. A general account of the Graafian follicle in its mature state having been already given at p. 550., the changes which this important structure undergoes at different periods of its development and decay will now be examined, * The question of the connection between men- struation and the maturation and discharge of ova from tlie ovary, is considered under the head “ Men- struation” at page 666. t Negrier, liecherches stir les Ovaires, chap. ii. iii. Kntwick. des Rehes, 1854. UTERUS AND ITS APPENDAGES. First Stage. Origin of the Graafian Follicle. — The time of tlie first ap[)earance of the fol- licle within the ovary is subject to considerable variation in the different orders of Mammalia. In all it occurs at a much later period than the first appearance of the seminiferous tubes in the male. Bischoff, who has devoted much attention to the e.xainination of the follicle in its earliest stages of formation, has never been able to discover the least trace of it in the dog and rabbit before birth. This is also the case in most instances in the human embryo, although examples occur of the ovarian fol- licles being already formed in the new-born Fig. .377. Represents the mode of formation of the Graafian follicle. {After Bischoff.') A, portion of ovary of a foetal dog. The Graafian follicles are seen in the first stage of formation, consisting of little groups of primary cells in the midst of a tissue of similar structure. B, Portion of ovary of a dog four weeks old ; a de- licate fibrous coat now surrounds the groups of nucleated cells. c, Portion of ovary of a pig three weeks old. The follicle is here composed of transparent membrane, the outer surface of which, in the larger ones, is become fibrous. Its inner surface is lined by an epitlielium of pale cells (membrana granulosa) ; within this is the germinal vesicle, surrounded by granules resembling yelk granules. These contents are seen dispersed from a ruptured follicle at y. infant, and in ailvanced embryos. At first nothing is distinguishable in the ovary except a uniform mass of primaiy cells and cell nuclei. When the follicle or ovisac is about to form, there may be perceived little round or ovoidal aggregations of [irimary cells, forming groups which are distributed in considerable numbers through the ovary. These, from the circum- stance that the substance of the ovary is like- wise composed of similar cells, are scarcely distinguishable from the stroma in the midst of which they arise (fig. 377. a ). Now Barry, who also very carefully exa- mined the early formation of the follicle in the rabbit, maintains that within these little groups of cells the germinal vesicle is already contained. Barry re|)resents the germinal vesicle at its first formation as surrounded by minute oil globules, and a collection of gra- nules, forming together little elliptic masses which are distributed through the ovary. A comparison of the descriptions and illustrations of these two observers leaves no doubt that both refer to precisely the same object. Round these little groups of cells is now perceived a delicate transparent membrane, which is at first apparently destitute of or- ganisation. This is the ovisac in its first stage of formation (fig. 377. n, c). The precise mode of its development has given rise to much speculation, which is interesting chiefly with reference to the question whether the ovisac is to be regarded as the vesicle of evolu- tion of the ovum, or whether the ovum, or parts of it at least, are previously formed, and the ovisac is afterwards superadded. Bischoff explains the formation of the fine homogeneous membrane which is first seen surrounding the little groups of cells by sup- posing that those which form the peripheral layer become confluent, and that by their junction they constitute this boundary wall, whilst the original cell contents are dispersed. This membrane soon afterwards becomes lined with a stratum of endogenous cells, which i'orm an epithelium upon its inner surface. .A close examination shows further that this cell layer is bounded by a homogeneous tunica propria. Hence Bischoff concludes that the follic'e is, as Henle asserts, a primary secreting fol- licle, which, like all secreting follicles, is not composed of a primary cell membrane, but results from a confluence of cells. He has never seen in it, when still in the condition of a homogeneous transparent membrane, a ceil nucleus, as would be the case in a primary cell. The contents of the vesicle, according to Bischoff, consist of a clear fluid containing cell nuclei and granules ; the latter closely re- sembling the subsequently-formed yelk gra- nules. Somewhat lateris observed within these follicle vesicles, which in the meantime have become more developed and numerous, a se- cond transparent s])herical vesicle, containing a nucleus which closely resembles, and is con- sidered by Bischoff to be the germinal vesicle. Hence, whilst the observations of Barry, con- firmatory of the views of Baer, and supported OVARY — (Functions). 555 now by Dr. Allen Thomson*, led the former to conclude that the formation of the ovum commences before the existence of the ovisac, the researches of Bischoif point, on the other hand, to the ovisac itself, as the formative or- gan of the ovum. The general appearance of the ovisacj 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 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. I The ovisac is sometimes formed in the pa- rietes of an already developed Graafian fol- ! licle ; but whether originating here, or, as is 1 more commonly the case, in the proper sub- I stance of the ovary, it is always at first seen ! lying perfectly loose in a little cavity, exca- 1 vated, as it were, in the substance of the sur- I rounding tissues. Subsequently a covering, I or tunic, consisting of a rather dense con- I 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 I outer covering now becomes closely united. I 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 I that age a section be made of the ovary, it I will be seen to be composed of a parenchyma, j which is somewhat lax towards the centre I and base, but more dense in the peripheral j portion of the organ. The more lax central j * Page 76. of this vol.. Supplement. 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 up almost entirely of a mass of minute ovisacs, already containing ova (fig. 373.). These ovisacs, at present in a rudimental condition, are of various dimensions. In the example given, their average diameter was suo— Ttfeo"- But it happens, occasionally, that ovaries of a very early age are found to contain ovisacs or Graafian follicles of com- paratively large size. Thus, in a specimen in my possession from a child of seven months, one ovary contains a follicle of rather more than V" in diameter, whilst the other is almost entirely occupied by five follicles, the largest of which measures 2i-h \ and the smallest is one quarter of that size. In this case the entire length of the ovary is only T'". Second Stage. Growth, Maturation, and Pre- paration for JOehhcence 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 follicles 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 orary. Several, riper than the rest, are conspicuous by their size, a, unripe; b, riper follicles ; c, stroma. (After Fouchet.j Each grain, a, consists of a vesicle filled with a limpid fluid, albuminous, viscid to the touch, of a slightly j-ellow 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., of the ovisac itself. From four to six of these vesicles will be found to become simultaneously developed in each ovary (fig. 378.5,5). Theseare 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, apj)ear in the form of a rich network u[)on 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 ly" 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 rui>ture, 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 residt of this process is, that the ovum, 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 disputetl, 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 jtoint, 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, ai'e 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 oif 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 huffy 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 ru[)ture at a certain part of the parietes. The base of the follicle continues to be imbedded in the substance of the ovary (Jig. 379.), but the upper [)ortion projects free above this, being covered only by the usual ovarian in- vestments. Here, at the more salient portion of the projecting vesicle (^g. 379.), an in- creased vascularity is observable. The peri- toneum ami sublying tissues become exceed- ingly red, and an abundanceof blood isobserved 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- |)lete 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. F/'g. 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 Mamiiialia, 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- OV ARY — (Functions). 557 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 ovarV: sometimes near its surface, and at others buried more deeply ; but^ when they increase in growth beyond this size, and aie 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 airest attention, and to point out the part of the ovary in which the dehiscence -will next occur (/•c 380. a). Fig. 380. Ovary from a woman aged 22, who died on the tenth day after the commencement of her last menstriuxl period. (^Ad Nat.') 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 tvvo, 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 fi"' — 2i'", or even S'", it has now a di- ameter of 5\ — 7'", the breadth being usually somewhat less than the length, for it rarely hajipens 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 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. b). Beyond this circumference, the base of the promi- nence exhibits the usual white colour of the ovarian coverings. Numerous red vessels, chiefly veins (fg. 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; h, a blood-clot. Nu- merous follicles of the ordinary size are seen scat- tered through the ovary. (y%. 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 granulosa, 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 ont 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 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 tlie follicle ififi. 381.), which is due to the growth of the inner membrane having con- tinued after the outer coat has ceased to ex- panil. 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 a[)pearance 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. Celts 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 luteiim. (^Ad Nat. x ooO.) 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. b). 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- vessel.s, and of developed as well as embryonic fibres of connective tissue, which latter, how- ever, are only faintly indicated, and are con- nected together by a transparent membrane. 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 to 4oVo”> ^ut 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 mai'gins of which are very readily defined. There can be no doubt that these cells are the “peculiar 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 luteinn — 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 aj)[)earance 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. h) 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, ami 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. ' 'I'hird Stage. Period of Pupture or Dehis- cence of Ike Follicle, and Escape of the Ovumf-^ — This is termed by Pouchet the period of parturition, in which, after the preparatory ' changes already described, the ovum quits' i the Graafian follicle in order to enter the j. Fallo|)ian tube. It is therefore for the ovisac l| what the process of parturition is for the i; uterus, viz., the act by which the ovum, after being matured to a certain point of perfection, is expelled from its cavity. j The process by which the dehiscence of the follicle is effected in Mammalia is in some re- spects different from that which causes the |i expulsion of the ovum, from its containing ^ capsule, in the vertebrata below them. In \ birds, reptiles, and fishes, and, indeed, in the Invertebrata generally, the ovum is of so 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, 3 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 ol , 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 ovipnnte {ovi- ■ pent), 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. i 559 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 (fg. 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 ajjproach 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 \iill 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 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 w'hich 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 w hich form the centre of the membrana granulosa, at the moment when the laceration occurs, experiences the vis d 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 which 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 w hich lies immediately behind the lacerated coats, where the ovum is im- bedded, presents a surface for the operation of the vis d 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 wmight ot 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 jtasses 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 coinpressoriuni, 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 ilragging after it portions of the retinacula (g, 2.) is shown in the act of escaping from the follicle. Fig. 38.3. Ooum o f the rabbit in the act o f escaping from a rup- tured Graafian follicle. (^After JBarrg.) The ovum is surrounded bj' the tunica granulosa, jt, and draws after it tlie portion of membrana granulosa termed the retinacula, ; at h, wliere 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 rotintl aperture in the midst of a bright red spot, which is margined by a little net- work of capillaries filled with blood {Jig. 383. Ii). In the sow the aperture is generally oblong Fig. 38I. Portion of ovary of the sow. Three of the largest follicles have burst siimdtaneously, and exhibit wide lacerations. Others, less forward, remain unrup- tured, At the base are several unripe follicles. (^Afler Pouchet.') (Jig. 38I.), and from li to 7"' m length; the^B laceration in the latter sometimes extending™ through the entire diameter of the follicle, and V permitting the escape of the whole of its con-^B tents, together with the ovum. The laceration is not necessarily limited to^| a single follicle. In multiparient animals^W (Jig. 381.) all or a greater portion of those^H follicles which have attained their full de-^H velopment undergo laceration, and emit theii^B ova about the same time. In some of these, however, the effort may prove abortive, andjH the follicles may remain stationary until an-jB other impulse to rupture occurs, and the ova^J' 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 possess the proof in a case (Jig. 409. page 005.) 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 ; akhough 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 i 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 i 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 e of their walls, as we have seen, burst and i| emit their contents. The whole of these changes occur in regular sequence, and aflect j one or more follicles in succession. These H 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 — 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 these 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 sufflcient here to refer to the fact of the spon- taneity 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, wdiich 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. (Functions). 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 o| 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 fibrinous 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 dispasitiou which the inner membrane of the follicle takes soon after 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, having 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. o o 502 UTERUS AND ITS APPENDAGES. The inner coat becomes folded, and forms convolutions, which increase and become deeper in proportion as the retractility of the e.xternal tunic increases. Ihese convolutions in the inner and now yellow coat of the follicle are so distinct and striking (jtg. 385.) as to have suggested those coin[)arisons 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 foldinss, constituting ridges and snici, 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- rjg. 385. Section of the ovary o f a woman who was poisoned by opium. A large Graafian follicle, which had re- cently hurst 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 JVat.) responding with the convolutions of the ovisac, hy 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 empt}', 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. Tliese 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, he tlrawn 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 hy the time that one or more of the 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 (Jig- 372. h) 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 diam. Finally, whilst the foregoing changes are proceeding internally, a corresponding altera- tion takes place at the surface of the ovary. 503 OVARY — 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 (y?g. 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 Imjiregnaiion. — 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 — If 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- Jeration of those altered circumstances in which the generative organs are placed after mnception ; for, from the moment that im- )regnation has occurred, all parts of the gene- rative apparatus are brought under the influ- ;nce of a common stimulus, and all manifest n a greater or lesser degree some progressive (Functions). 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 ini|)regnation, 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 o o 2 5G4 UTERUS AND ITS APPENDAGES. wliich 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 tlie 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 |iresently considered ; or else it may happen that the cavity becomes obliterateil by the organisation of the clot by which it had been at first fdled. After conception it is probable tliat 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 wdiich it is usually found to have, in different instances, during the first four mouths of [iregnancy ; 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, solidity, and other par- ticulars obvious to the unaided senses, and all the histological changes are to be looked for w'ithiu the outer coat of the follicle. The latter appears to suffer no alteration, but simply to follow the movements of its contained l)arts, around which it remains loosely applieil. 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 w hose 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 surronnd- iug stroma into which the vesicle has now begun to sink, becomes more deeply plicated ; and since it can no longer extend outwardl3’, it must of necessity encroach rqion the cavity within. The latter thus becomes sensibly diminished, whilst the entire thickness of its boundary wall is m like proportion increased. At the end of the first tw'o months of ges- tation, the follicle i>ossesses consiilerable 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 consiilered 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 the,se and other changes which ensue is still the ob- literation of the structures in which they occur. Tlie process of obliteration, however, has at this time not [>roceeded so far as to have caused the removal or even diminution of any of the original parts composing the follicle, w’hilst some new structures are super- added or produced by metamorphosis of the original materials. The follicle at this period generally affords the best opportunity I'or observing the changes which result from im|n’egnation. It may therefore be selected fora critical examination of the subject. The extenial condition of the ovary in which such a follicle is contained serves at once to point out the j>recise seat which the structure occiqiies. 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 |iass through the centre, but to include only a |)ortion of the circumference of the follicle, the latter will present the condi- tion represented in /ig. 386. The follicle, in the Fig. 386. Section o f 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 projects above the stroma. {Ad Nat.) a, outer vascular coat (tunic of the ovi.sac) ; b, yellow inner coat (ovisac), from which a thin slice has been removed, not deep enough to lay open the cavity, but displaying the brain-like convolutions; e, portion of the follicle corresponding to b. form of a little globe, is seen to occupy aboul a fourth part of the ovary. Its solidity ant spherical form cause it to project considcrablj above the surface of the section. In this \vaj is exposed the outer coat by' which the folliclj is bounded. Upon this coat numerous blood vessels, derived from the ovarian stroma, raj mify. It is the tunic of the ovisac, the origil 563 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 tines it internally but the yellow ovisac. Neither between its outer nor its inner surfaces, and the 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 histological elements are sini[)ly 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 11'". In its substance may still be seen traces of the original foldings or convolutions. These are more easily showm upon the sur- face of the first section ()%. 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 follicle as in fig. 38G. 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) ; e, white membrane lining the cavity (a new forma- tion) ; d, cavity empty. coat shows greater solidity (Jig. .387.). Up to this time, however, anti 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, 1-1|'" 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, w'hich are at first also very minute, but soon collect and * Montgomery, Signs of Pregnancy, p. 227. 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 subsetpiently 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, transpai'ent membrane. The outlines of the Fig. 388. nuclei are very sharp and distinct, and wdthin 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 [ire- cisely the milk-w hite 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 b_v 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 semitransparent membranous medium as to be inse|)arable into distinct fibrillm, 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 ever}'- where seen scattered throughout the mass, and adherent to the detached fibrillm. 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 56G UTERUS AND ITS APPENDAGES. stance lias the appearance of a tissue whicli 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 occu[fying 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 may 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 dis[)oses 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 coinjilete obliteration approaches; but through all the subsequent changes of the I'ollicle the same anatomical structure and the same rela- tive position of parts is preserved. In the original preparation from which yfg. 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 mfig. 387. the cavity measured 3'" in diameter and con- tained a clear gelatinous hiiid. 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 followout 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 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 {Jig. 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 {Jig. 389.) caused by the folding of the white lining Fig. 389. Graajian follicle two days after mature delivery. The white tilling of the cavity 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.) memhrane 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 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 — Foes the discharge of ova from the ovary teke jdace independently of se.runl intercourse, or of any kind of injinence from 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 genera! 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). 567 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 demantled. 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 uniinpregnated ovum in the oviduct. The following case is related by Bischoff.* Alamb which had never received the male, and w'hich 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 i"'. 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 b"' 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 BischofFin 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 Puberty, p. 376. 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 bad 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 tuteum, 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 ovarij 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 I 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 UTERIjS and its appendages. taneous ovi[)ont in mammals is e.xceedingly 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, CosteJ.and Ponchet.§ The first only of these authors has given in detail the observations and experiments upon which he has enileavoured to found a law of spontaneous ovulation in the Mammalia. In several of these the coitus was permitted ; and although it is rendered highly |)rohahle, from the cir- cumstances narrated, that in some this had no effect in producing the discharge of ova, yet the introtluction in any form of the only con- dition that could vitiate the experiments de- tracts certainly from their value. In five, however, of Bischoff’s experiments it was known that coitus had not occurred, and in three of these ova were fountl discharged, ac- companied by the usual appearances in the ovaries indicative of the recent rupture of the follicle. II In a fourth case, the stale of the ovaries left no doubt that the ova, which could not he foumi, had escaped; while a filih 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 quoteil. 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 a|)parently from separate observations ; but these descriptions are not accompanied by any detailed ex- amples, nor any statement of the means used lo 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, w'hilst they differ as to the degree of strictness with which the universality of this law is enforced. Pouchet demands that the law should be received without aTiy 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 unabhiingigen periodischen Keif'ung und Loslosung der Eier, Sec. 184t. t De la Puljerte, et de la Ponte periodique. 1844. J Histoire du Dcvelopperaent. 1847. § Tlfoorie positive (le I’Ovulation spontanee. 1847. II 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 tanly, 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 advanee 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 ot being deter- mined by experiments on animals. All the earlier observers who directed their attention to the condition of the ovaries in relation to reprodtiction 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 e.-- cape, and he had almost given up the attempt in despair. If means be used to prevent the contact ot 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). 569 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 nnimpregnated 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- cessary to pursue the subject further here. (See page 660.) 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 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 (larticidar 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, coipus callosum, 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 betvveen 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 ” corpus 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. luit is calculated to mislead by suggesting tlie idea that the so-called “ true” corjms lutcum 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 for it may be possible to determine, from the physical a[)pearance of the follicle, whether im|)regnation 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 evitlence 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 detectecl 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 possibl}' 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 j'ellow - 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"'. 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'". The inner coat is of a bright yellow colour, and ex- hibits slightly wavy folds (Jigs. 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 wita that portion of the membrana granulosa wdiith lay beneath the scat of the rupture, has es- caped, or is about to escape. The follicle is beginning to collapse. Its walls, tio longer distended, become folded into numerous small plaits, producing, on section, the ap- pearance resembling cerebral convolutions. The cavity is comscquently 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 571 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'). id. 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, (Jig. 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 {fg. 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. — JV/iai evidence does the condition of the ova- rian follicle afford, first, as to the jrrevious 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 hy 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 afford 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 be diffi- 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 Altei'ations U’hich it undei'goes 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 w’hich 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 Societ}’ of London no trace of an ovai'3' 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 Wollfiana. 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'", 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 0‘U". 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 (y?g.4‘10.). In the fbetiis at term the ovary has usually attained a length of 4-5''', and a breadth of 1 ,5-2'" {fig. 44 1 . ). Its figure is an 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 10-12'", 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 approaclies, when it grows more rapidly and acquires the form and dimensions already described as characteristic of the ma- ture organ { fig.'idd.). 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. ill. 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 qirestion by Dr. Ritchie, who, after detailing a series of obseiwations upon the condition of the ovary at various periods of life, asserts that “ the Graafian vesicles contained in the ovaries prior to nienstm- ation are found, as they also are in every other period of life, in continued progression towards the circtimference 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.” i It should he 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. ' 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 twofohl. The surface becomes scarred in all directions by the closing up of Fig. 390. Ovary about the time of cessation of menstruation. {Ad Nat.) ■ tlie lacerated openings, whilst the successive discharges of the contents of the ovisacs gradually diminish the bulk of the entire or- {f‘S_- 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 ami tortuous Fig. 391. Ovary in old age. (^Ad Nat.) lines {fig. 391.). When sections are made of the ovary in this condition, it is found that all tracesof the Graafian folliclehavedisappeared; 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 jiarenchyma. 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 especiall' 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 u[Jon 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 on!y> however, is there a local hyperEeinia 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. 573 OVARY — (Abnormal Ana’iomy). Abnormal Anatomy of the Ovary'. Effects of extirpating the Ovary. — A natural deficiency of the ovary together with the oviduct of one side is known to prevail in the class Aves, hut 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 Yvas .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 ])erfect 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 tlierefore 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 time 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 e.xternally 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, how'ever, may not occur. The ovary may cease to grow after the third or fourth year, ami, under these circumstances, the whole organism manifests a corresponding tardiness of development. An interesting exam|)le 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 Yvithout having menstruated. The ovaries, as well as the rest of the organs, are no larger than those of a child of three years (seeyfg. 465.). In these cases the mammre 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 tile 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 bein 3 582 UTERUS AND ITS APPENDAGES. Fig. 39G. Part of the thick laminated wall of an ovarian cyat., covered on its inner surface with pyriform vesicles. (^After Paget.') The Cott/enf.s of Ovarian Cysls. — No cystic formations in any part of the body present such a variety of contents as those wliich are found in the ovary. These vary in every de- gree of consistence, from the thinnest fluids to the liardest substances, such as teeth ami hones. They may be subdivided according to tlieir densities and different degrees of organi- sation. And first may be considered : — The Fluid Cuntenls of Cysl.s. — 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, pi'esenting every variety of consistence fi'om 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 jiroduced 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 stateil, recent blood or the blood clot under- going fibrillation, or breaking down by putre- faction, may be frecjuently 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 coni|)osition. Thus, that which is obtained by a first tapping is often of the thin straw-co- loured variety, whilst that which results from subsecjuent 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 tlie 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 rlie 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 [uis, rough patches, apparently of ulceration, have been observed upon their internal walls. Quantify of Fluids and Rale of Effusion. — The structure anil situation of the ovary per- mit this organ to suffer a degree of distension which is rarely or never equalled in otlier parts. Probabiy the only limit to the increa.se 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 up.)u the cyst ; for the parietes of an ovarian c}St appear in most cases to possess an unlimited capability of multi[)lying the fibrous element of which they are princi|)ally composed, whilst, the power of rapidly replacing the fluid after their contents liave been drawn offj proves both the unrestricted capability of secretion inherent in the cyst walls, and at the sa'ne 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. Indioff* records a case in w'hich the light ovary contained 42 lbs. qt fluid. Duretf met with 50 pints ot water in * Acta Helvetica, vol. i., App. p. 1. f Mem. de I’Acad. de Gliir. t. ii. p. 457. 583 OVARY — (Abnormal Anatomv). a single ovarian cyst. And in the London Medical and Physical .Tournal (Aug. 1815) the particulars of a case are given in which the right ovary weighed nearly 52 lbs. But these are moderate examples compared with some of still larger growth. Camper* relates a case in which about 80 lbs. of serum were contained in the left ovary ; and Douglas also one in which the left ovary held 70 lbs., besides a considerable collection of fluid in the pleura and pericardium, f 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 lbs. 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 Saffbrd 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. PagenstecherjJ removed, in 35 operations, 1132 lbs. 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 || punctured the ovary 49 times, and removed in all 2786 pints of fluid. Heidrich* in eight years punctured 299 times, and removed 3289 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. INIartineau, 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 albumen 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 comparetl 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 lai'ge quantities for the express purpose of detect- ing that substance. The following table -j-, by Dr. O. Rees, gives the results of the analysis of four fluids drawn from secondary cysts of an ovarian tumour, compared with an analysis of the serum of blood. Ko. 1. Clear, light straw- coloured Alkaline. Sp. G. 1017. No. 2. Dark- coloured muddy neutral. Sp. G.1017. No. 3. Approaching in character to white of Alkaline. No. 4. Clear straw, coloured, containing flakes of a pearly scaly- looking substance. Analy.sis of the Serum of the Blood for comparison. Water ----- 190-9 190-70 195-2 187-7 181-2 Albumen with traces of fattv matter 4 1 4-25 1-8 7-6 10-5 Albumen existing in solution as Albu- \ 3*7 3-02 1*1 0-4 minate of Soda - - - I Alkaline Chloride, and Sulphate, with ) 4-0 Carbonate of Soda, from decomposed V 0-8 0-78 1-2 1-Gt> Albuminate - - - - j 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 i-eferred to by Meissner (Die Frauenzim- nierkrankheiten. Band ii.), in which a single ovary is said to have weighed 100, 120, and 150 lbs. re- spectively. t B. v. Siebold’s Sammlung, 1812, iii. Bd. § V. Siebold’s Journ. fur Geburtsh,b.vii. St. i.s. 93. 11 Medical Communications, vol. ii. 1790. * Dissert, sisteus Casum Memorabilem, Berol. 182.5. f F rom a valuable paper on Tumours of the Ovary, b)' Dr. Blight, in the Guy’s Hospital Eeports, vol. iii. p. 204. J Tlie whole of the Alkaline Salts are estimated together in the analysis of serum as indicated bt^ the line. p p 4 584 UTERUS AND ITS APPENDAGES. So far, therefore, as these analyses may he taken to represent the orilinary com|)osition' of the more Hiiiil contents of ovarian cvsts, it may be concluded that the action performed in these cases by tlie walls of the cyst is the separation from the blood chiefly of the watery and saline ingredients, with the exception of alkaline phosphates, wliilst the albumen is only in part removed, and none of tlie fibrine. Examined by the microscope, the more fluid contents of ovarian cysts frequently ex- hibit flocculi, composed of patches of e|)i- thelinm, 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 tlie jelly by tlie formation of pus cor|iuscles or minute granules, and sometimes the con- tents are wholly filamentous, and mixed with granular cells and other [iroducts 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 tlie 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 [lossession 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 stuff’ed 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 ?) Conqiara- 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. p A girl aged 17 had a swelling of the left ovary, vvhich 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 14 lbs., and contained also 40 lbs. of a thick, fatty, honey- like substance, mixed with short and long * Dr. J. H. Bennett on Encysted Tumours of the Ovary and Pelvis, Edin. Med. and Surg. Journ. Ko. 167. 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 ami 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 morbiil 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 pre,s- 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- rausch -|-, Lebertj;, and Paget. § “Upon their inner surface is producetl a growth of skin, with its layer of cutis, subcutaneous tat, epi- dermis, and all the minute appended organs of the pro|)er 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 ot 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 Siidoriqyai'ous Glands liave been shown by Kohlrausch and Heschl to be present in these cysts, where they have the same general arrangement as in the skin {fig. 397. c). Fatty Matter. — This occurs under two forms : first, as a loose granular fatty sub- * Anat. Pathol, tom. i. livr. xviji. t Muller’s Arebiv. 1843, p. 365. j Traite d’Anat. Pathol. § Lectures, vol. ii. p. 83. 585 OVARY — (Abnorjiai, 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 (Jig. 397. d). This fatty material is of a white or yellowish hue, and is commonly inodorous, hut 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 fetid pus has been formed within the cyst. The second condition under which fat is found is that of masses ^ — \" 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 (fg. 397. a). These present the ordinary character of adipose tissue, but pos- sess a smaller proportion than usual of the cellular element. Ilnir 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 ma}' 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 woolly hair of the head ; they were soft, smooth, red, or blonde, and some were silvery, 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 tat. 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 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 C3'st 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 lamelfe, Haversian canals, lacunte and canaliculi. Such bones often bear a sufficient resemblance to frag- ments of jaws and vertebrte to admit of a general comparison with tliose 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 matter., adi-' pose tissue, sebaceous glands, and hair follicles. (^After Cruveilhier.'j 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 teetli were contained in this cyst, togetlier with a portion of tegumental struc- ture, subcutaneous fat, hone, and hair. 586 UTERUS AND ITS APPENDAGES. of the cyst covered by integument are seen to be elevated, and it is in tlie substance of and beneath such elevations that the fatty tissue and bones are usuall}' fouml 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 ex[)lain 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 iiortions of a second fetus, 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 c}'sts 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, vvhosegenerative organs vvere 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 boily, 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- ])lied 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 towarcls 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- viou-sly fails to satisfy any imjuiry as to the * Royal Coll, of Surg. Pathol. Collect, prep. Ko. 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 (f) — OvarianGestation. — Graviditas Ova- ria. — Few facts in physiology have been more readily assumed without sufficient examina- tion than that the fetus 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 ini[)regnation 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 fetus has attained or approached to full growth, and the sac by which it is surrouuJed has already contracted adhesions. All the examples that I have had the oppor- tunity of dissecting, or of seeing exanjined, 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. 5S7 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 Faliopian 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, remlering 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 fetus, 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 few hours which succeed to the final de- struction, the parts decompose so rapidly that . the post-mortem examination, however early I it may be made, often reveals nothing but a I 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 exam[)les, 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’ fetus j- is seen hanging external to a sac, occupying the seat of the right ovary, in which it is supposed to have been once con- tained. The sac said to be in the inner and lower part 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 attem[)t 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 lan example of tubal, or ovario-tubal, as of i * Anat. Pathol, livr. xxxvi. pi. vi. I t 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. ovarian gestation. The fact also that the cyst had apparently burst and [termitted the escape of the fetus 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 dravvings, whicli he regards as an “ undisputed case of purely ovarian fetiferous ovum.” The uterus is considerably enlarged, but empty. “ The left ovarium presented a large swelling which contained within its own covering an ovum bearing a fetus with all its ap[)endages, 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 htemorrhage. 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 corres|)onding 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 per- 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 fetus 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 fetus. 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 fetus w'as not a cyst attached to the ovary. But the evidence in favour of ovarian gesta- tion consists chiefly in this, that the fetus- bearing cyst occupied the region of the ovary, and was independent of the Fallopian tube. Nevertheless this case constitutes the nearest aj)proach to the form of gestation wdiich 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 fecundum 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 embry o hung pendulous * Phil. Trans. 1820, and Graphic Illustrations of Abortion, Plates X, A, and B. t P. 27. pi. viii. UTERUS AND ITS APPENDAGES. r>88 from the yet visible nulimcnt of an umbilical coril. That embryo, however, is not now to be seen.” The female from whom ibis was taken was unmarried, but acknowledged her- self to be pregnant. The uterus was larger than in the nnimpregnated state. The Fallo- pian tube was not in the least involved in the enlargement. Tlie 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 regariling the reality of ovarian gestation,” is recordeil in the Transactions of the College of I’liysicians.-)- From the descrip- tion ami drawing which accompanies it the followina: chief particulars are learned. The uterus, from a woman aged .30 who iiad com- mitted suicide, was larger than the ungravid organ ; its body somewhat globular ; its sub- stance, exce|)t the cervix, spongy. A decidua nearly thick, soft, pulpy, and of yellowish- white appearance, lined the interior of the uterine boily. The cervix was filled with gelatinous matter, but not sealed up. The vessels of the broad ligament and appeiulages 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 a[ierture 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 ami 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. Tlie 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 distinguishetl. Around the ovum for some distance the ovary was loaded with blood elFused 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 peifect knowledge has been obtained of the various conditions of the ovary in health and disease. Changing the names employetl 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. X 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 cy st 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-vcssels, without an embryo to form them, and still more of explaining how the seminal fluid could reach the ovum through a membrane whicb is described as “ perfectly smootli,” 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 tiie 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 [larts 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 gestat'on, and of which it may be remarked that neithei arc. of recent date, tlie one having occurred thirty-eight years ago, and the other at least as earlj' — at a time, therefore, when ovarian gestation had not been questioned, and the, ovarian ovum in intui had not yet been discovered. The preparation, de- scribed and figured tiy Dr. Granville as belonging to the late Sir 0. M. Clarke, is now in the posses.non of IMr. Stone, whose kindness a more particular, examination of it has been permitted. For this purpose, the preparation was recently placed ;n the hands of Professor Owen, by whom it was remnycd from the bottle, and minutely examined under spirit. At this investigation, I was also present, together witli Mr. Stone and Dr. John Clarke, and I had the opportunity of making repeated microscopic exami- nations of everj' portion of the ovarian structures. The result of the investigation showed thai the structure supposed to be an impregnated ovum con- tained in the ovary, althougli it had such a general appearance as might without this examination have borne the interpretation whicli had been originally put upon it, was liothing else than an ordinary ova- j 589 OVARY — (AbnoRxMal 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 a strict ovarian gestation, and they serve to exliibit 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. riaii cyst. The walls of the sac showed no separa- tion into distinct membranes, and no trace wdiatever of the structures characteristic of either cliorion, 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 portions 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 hail 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 Eoyal College of Phy'sicians for 18'20, 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 appeal's 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- lomeiv’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 know’n 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. * A large collection is contained in the work of Dr. Campbell just cited. 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 w'ould 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 w'ay 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 w'hat 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 fetal membranes with the sac, been accurately traced. Nor has the condition of the yellow or corpus luteum coat of the follicle, of w hich 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 theuteriis 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 know'n to quit the ripe Graafian follicle by passing through an aperture spontaneously made in the walls of the follicle and of the ovar}', in order to enter the Fallopian tube and uterus, in one of which canals it is afterwards impregnated. * It is thought by Boehmer that these cases might be divided into external and internal. 590 UTERUS AND ITS APPENDAGES. It becomes a question whether this law, wliicli lias 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 fetus 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 nnimpregnated, 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 fetus 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 fetus 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 fi'equently doubted or denied, that these cysts derive their oi igin 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 anti Wedl may be considered as still holding uncei'lain 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 Wetll 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, w'hich originate in the dilatation of * There is nothing in this supposition incompa- tihle with the known facts relative to the spon- taneous opening of the follicle, and the power of penetration of the spermatozoa occasional!}' 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 Weed be adopted, that they consist in an excessive augmentation of volume of the areola 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 coni- jtosed 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 u|)on 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 fonnation once given in an organ, even by the primitive enlargement of Tiormal cavities, a marked tendency to the autogenous formation of cysts follows.* But even if no other explanation could be offered, the discovery of Barry, that the walls of a Gi'aafian 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, 1 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 develo[)cd 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 smiilar 1 formation and structure in every gradation of l size up to those examples in which the ovary il itself comes to be a mere appendage of the I Lcbert, loc. cit. p. 244. 591 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 ot life when the Graafian follicle is in a state ot 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 ot 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 Enlargemcuts 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 de[)osited 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 cancroid cases, most, if not all, of the specimens which have been described or preserved in museums as exanq)les of large fibrous tumours of the ovary, have been formed at the expense of the proper tissue of the uterus, and have had nothing 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 siqi- 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 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 tlie 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 amplilying 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 ivith Cysts, — These might have been classed. 592 UTERUS AND ITS APPENDAGES. as has been done by Rokitansk}- and Lebert*, But such an arrangement, whilst reco^nisino' with the other forms of cystic disease of the an important feature, often, but not dways'’ ovary, on account of the frequency with whicli observed in colloid cancers of the ovary, of this form of cancer is found associated with necessity dissociates these cases from other ovarian cysts, especially of the larger class, congeneric forms of disease. In this particu- F/g. 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 whicb, thougb 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 ec]uaHing 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 * Kokitansky, however, regards these eases 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 fiat- tened, in consequence of the [irofusion 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 slriic- j 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 ile pends the general hardness or softness of the mass. This intermediate substance is in soiiiel instances so thick that the cysts appear like excavations in a dense medium, but often the cyst walls are so thin that the peripheral folliclesi project in the form of thin-walled sacs from the surface, and the whole mass is sonietiniesj so feebly supported as to assume the appear ance of a trembling jelly. The thin-walletj cysts are generally richly supplied with blood-Ji vessels. Tliese cysts are filled with a viscid mucous like material, resembling half-liquid jelly, whiel is sometimes colourless, but oftener of a gray ish amber, yellow-green, or reddish hue. Inij 593 THE PAROVARIUM — (Normal Ai\atomy). 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 Cancer 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 difflision 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 he number and variety of the contiguous structures which may be thus involved, the jvary may sometimes be traced as the centre )r focus from which the cancerous deposit las spread. This was remarkably the case in in example of medullary cancer, which was or some months under my notice, where the lisease commenced apparently in the left ivary, and was found to have spread from his point upwards along the chain of ab- orbent glands on the corresponding side, as ;ar as the pancreas, and outwardly through the schiatic notch to the gluttei, and all the ad- 'acent muscles, including in its destructive march the os innominatum, which could be 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. 26-12. 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 ai’e b}' 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 (y%. 16. Atlas) occurring in a girl of 16, associated with tuberculous disease of the mucous membrane of the uterus. In eases 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 PAROVARIUM. Syn. Corpus Conicum. Neben-Eierstock, 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. Miiller. And it has recently been re- examined, and very accurately described by Kobelt J, in an essay devoted to this subject, in w’hich 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 Quasdam de Ovariis Embryonum et Foetuum humanorum. Leipsias, 1802. t Der Neben-Eierstock des VVeibes. Heidel- berg. 1817. 594 UTERUS A>JD ITS APPENDAGES. of peritoneum, after investing the Fallopian tube, passes off towards the ovary, to tbrin the |)OSterior duplicature which encloses the vessels proceeding to that organ, will be fonnd a small |)lexus of white tortuous tubes, {Jig. 403. «, 5, c) arranged somewhat in the foi in 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 12 — 20 tubules O’ 15 — 0’2''" in diameter. The tubes which contain nothing but a clear fluid consist of fibrous membrane, lined by a single layer of pale, cylindrical, epithe- lial cells. These tubular canals are not known to have an}- 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 iieculiar to foetal life, ami 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 epididtmis. Rathke believed that they became epididymis in the male, and disa|)peared in the female ; while Rosenmiiller, who discovered the paro- varium, compared this body to the epididy- mis. Some general conjectures also have pointed in themalesexto tVievascula aberranfia 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 |)retended ephemeral structure npt 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, (Jigs. 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 boily. To the inner side of each canal is attached a series of blind pouches {Jig. 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 ( fig. 399. and 400. a) and supra- renal bodies, {Jig. 399. f, 400. d) and as these increase, the Wolffian bodies diminish. The testes (fig. 399. e) and ovaria (Jig. 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 Aldller.') a, kidney; &, ureter; c, Wolffian body; rf, exore- | tory duct of the latter, which, according to the '! views of Muller and Kobelt, afterwards becomes the I vas deferens ; e, generative gland, afterwards be • j coming testes ; f, supra- renal capsules. j In the female chick, according to Muller, there is always seen an oviduct (Jig. 400. g). Fig. 400. Kidneys, Wolffian bodies, ovaries, and oviducts of a fatal bird, at a period when both oviducts are still of nearly equal size. Magnified. (After Muller.') a, kidney; b, Wolffian body, c, ovar}', the right* rather the smaller; cf, supra-renal capsule ;/, ex- cretory duct of the Wolffian body, which in the female becomes obliterated, but in the male is c.on- verted into vas deferens ; g, duct of Muller, after- wards oviduct or Fallopian tube. * The drawing has been reversed in engraving. The left, therefore, should be here the right side. 595 THE PAROVARIUM — (Normal Anatomy). distinct from the duct of the Wolffian body (_^g.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- tor}' 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. Thej', however, possess the same arrangement of transverse caecal tubes ( Jtg. 401. a — d), 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 Midler’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 ceecal tubes (y%. 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 (/i), 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 (k). This last cord. discovered by John Muller, is throughout destitute of any connection with the caecal pouches. (See also^g. 400. g.) Fig. 401. h The left If olffian body at the period of indistinction of se.v. (^After Kobelt.’) a a, entire collection of its component tubules divisible into three sets, viz., 5, upper; c, middle; d, lower set ; e, excretorv’ duct of the Wolffiim body into which all the tubules open, subsequently con- verted into vas deferens in the male, and becoming atrophied in the female ; f terminal bulb of the same, becoming afterwards the so-called hydatid, often seen attached, in the male, to the head of the epididymis (fg. 402. /), and in the female to the broad ligament 403. / and 408. p ) ; open- ing of theW’olffian body into .r, the uro-genital canal ; //, duct of iVliiller, afterwards Fallopian tube in the female, and becoming atrophied in the male ; i, ter- minal bulb of the same, becoming the hydatid of Mor- gagni (fg. 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 Muller with the uro-genital canal ; * show's 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 lii-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 (_^g.401. /), may be con- verted into testis (Jig. 402. /), or ovary (_fig. 403. /), and through the doubly existing ex- cretory duct of this gland, viz. the duct of Muller (y?g. 401.^), for the female, and the Q Q 2 Muller’s Physiology, by Baly, p. 1637. 596 UTERUS AND ITS APPENDAGES. excretory iluct of tlie Wolflian body (7?g.401, c) for the male, the capability of conver- sion into either sex exists at this time in every individual. The division of sex begins to he anatomi- cally discoverable by the development of one, Fig. 402. Adult testis and epididi/mis, anterior view. {After Kobelt.) a a, entire series of metainorpliosed tubules of the original Wolffian liody ; b, remains of tlie u|)per set, converted into the hydatid in the head of tlie epidi- dymis; c, the middle set converted into the coni vasculosi ; d, the lower set converted into the vasa aberrantia; e, excretory duct of tlie Wolffian body, now the canal of the epididymis and vas deferens ; f, bulb of the same, now a so-called hydatid ; /i, duct "of Muller, not destined to be developed in the male ; 1, 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. ami the stationary condition or disappearance of the other of these ducts. From this point. therefore, the course which each of these organs takes, is diHTerent for either sex. The male Wolffian body never disappears in all its parts, hut is converted into the epididy- mis in such a manner that the middle line of cascal tubes {Jig. 401.c c) is transformed into the 18 — 20 coni vasculosi (Jig. 402. c) ; while their straight and open ends, as vasa eff’eren- tia, establish a coniinnnication with the rete vasciilosiim testis. The upper blind pouches (Jig.W 1.17, b) and the bulb (f) of the excre- tory duet disajipear, or become converted into the hydatids (fig. 402. b, f) upon the head of the epididymis, while the inferior [louches (Jig. 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. f/). The excretory duct of the Wolffian body (J'g. 401. c) is converted into the canal of the epididymis, (y?g. 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, (Jig. 40.3. e) it constitutes a patho- logical condition when it occurs in the male. The terminal bulb (^fg. 401. i) of the duct of MLiller is converteil into the hydatid of Mor- gagni (,/ig. 402. /), whilst its inferior por- tion (jig. 401. it) still exists, at a later period in the anterior border of the epidi- dymis (/g. 402. b). Tracing the rlevelopment 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 Adult parovarium, ovary, and Fallopian tube. (After Kobelt.) a<7, 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; A, the former duct of Midler, now Fallopian tube, with its infundibulum, from which hangs i, the terminal bulb, now converted into a pedunculated hydatid ; I, generative gland, now the ovaiy. These three last figures are from Kobelt, whose views they illustrate. The letters refer to correspond- ing parts in each. it 597 FALLOPIAN TUBE OR OVIDUCT — (Normal Anatomy). pouches (fig. 401. c c), are converted into the 18 — 20tubules ofthe parovarium (^^.403. c), and tliese secerning tubes become organi- cally connected with the hiluni of the ovary, /. Tliey 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. fi/j), which are so commonly mistaken for morbid struc- tures. The inferior blind pouches 401. d) remain and represent the vasa aberrantia of Haller (fig. 402. d), 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 (fig. 401. e) in the female, undergoes a retro- gression in its whole length, and the lower end disappears entirely. (F/g. 403. e). The duct of Miiller (fig. 401, //) is con- verted into the Fallopian tube (fig. 403. //), 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 in fi'g. 368. e e, is very constantly present in the adult. Like the so-called hydatid (y?g. 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 consti ueted 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 paroYarium. 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. Puhce uteri vel FallopiancB ; oviducti ; vasa spermatica vel ejaculantia, Lat. ; Muttertrom- peten. Germ. ; Trompes uterines, Trompes de Fallope, Fr. The Fallopian tube (fig. 3G8. c c, and 404. a b c) is the e.xcretory 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 of 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 [losition 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 |)roduct. The action of the tube, however, is then imperfect ; and, when im- pregnation obtains, an abnormal form of ges- tation usually results. Form and dimensio)is. — 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 apitears to arise. The form of the tube was compared by Fallopius to that of a horn or trum(>et, w hich 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 (fig. 404. c), and proceeds outwardly gradually and regularly w idening up to its dis- tal extremity, w’here it contracts somewhat Q Q 3 598 UTERUS AND ITS APPENDAGES. suddenly just before terminating in a widely flexuosities, which produce an appearance of expanded funnel-shaped orifice. In the latter contraction at intervals. But that no such half of its course the tube exhibits certain contractions really exist is rendered evident by Left Falhpian tube from an adult. {After Richard.') a, pavilion and fimbrioe ; b, body of the tube ; c, abdominal orifice ; d, tnbo-ovarian ligament and fringes ; c, commencement of the tube; //.tubal mesentery; g, ovary; h, ligament of the ovary; i, uterus; I, round ligament. distending the tube with air or water ; a pro- eess which invariably removes this a|)pearance, and serves to demonstrate the unilbrm 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-^ — 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 |)roximal end. Just at the point of emergence from the uterine border, where the tube is firm and cord-like (Jig.iO-i.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, wdiere it measures 2^'" ; from this point the enlargement is moi e 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, anil 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 (j%. 404. c), 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. 3(38. 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- tacheil 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 tnbo-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 599 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 (/?g. 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 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 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 pnrts and divuions. — 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 nterina, expands into a gradually widening tube (fig. 405. c), 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 abdominale {fig. 404. c). But this does not form the termination of the oviduct, for the latter itnmediately widens into the trumpet- like orifice {infundibuhim)', 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 Uteras,” in this article. {fimbrice), (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, niorsus 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 demarcation 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 U 4 600 UTERUS AND ITS APPENDAGES. can no longer be discerned, and a slightly |)laited condition of the lining membrane of the canal begins to he distinguishable (fis,. 405. h). At this precise ])oint is found the true uterine orifice of the canal, the diameter of which varies in different subjects, hut 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 h, 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 patnlons to admit of the passage of a fine probe. Uterine portion of the tube, pars vtcrina. — This, as just stated, is the portion of the ovi- duct which traverses and is included in the suhstance 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 405. 5). 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, lint not laying open, the canal. The peculiar white colour of the tube is thus made to con- trast strongly with the surrounding darker uterine tis.sue ; and this (leculiarity 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 infnndiluilar-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 teft unopened. (^Ad Nat.) or more commonly turning rather suddenly downwards, and forming, with its first di- rection, an angle of 60° (fig. 406. and 4.31.). Strictly, the Fallo[)ian tube should be deemed to commence at this point ; and this should be regarded as the true ostium titcnnum, 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 cornn of the nterns 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 bodi/ 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 valviilae 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 nterns 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 — 'i'", and are themselves co- vered by an infinite number of little crests, often imbricated the one upon the othei, 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 oneofthe.se large folds always extends beyond the ori- fice. External orifice, ostium abdominale. — This occupies the bottom of the funnel-shaped expansion or trum[iet-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 nurgin in which they terminate. The aperture is fringed in its entire circumference by the plications of the memlirane already described (fig- 405.}. These radiating towards the centre appear nearly to obstruct the entrance of the tube. * Tlifeso, p. 35. 60] Fallopian tube or oviduct — (Normal Anatomy). which, however, during the middle period of life is usually of sufficient capacit}' 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 Infundibulum 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 anti construction as this, ami 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 descrijjtion 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 examinetl under water, has been commonly neglected. But without the support deriveil 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 leaflets, which are merely continuations of the larger and smaller plicas 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 [jrecisely 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 in figs. 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 mav 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 along the tubo-ovarian Fig. 407. Portion of Fallopian tube from an adult. (^Afler Richard.') a, external surface of the fimbrisB; h, line of demarcation between the mucous and serous membranes; cc, body- of the tube; d d, tubo-ovarian ligament, presenting scarcely any- trace of the fringes. ligament does not occur, but commonly the margin is uneven or scolloped, as shown in fig- 407. At this point, the opportunity occurs of examining an arrange ment of parts which is unique in the animal economy, viz., the con- junction of a serous with a mucous mem- brane. The line of junction of these two * Richard, Thbse, Anatomic des Trompes de i Ut€rus 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 Jig. 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 JhnbricE, lacimcB (Act/fi's), or morsiis 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 plicae, 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 finnly attached by both ends, while the body extends horizontally in the form of a flattened band among the rest of the fringes, as at Jig. 403. d. The backs of these are always covered by a continuation Fig. 408. Abdominal end of riyht Fallopian tube, from an adult. After Richard.') n, fimbrire irregularly formed ; cc, bristle passed through an accessoiT pavilion ; d, horizontal band across the mouth of the tube formed by one of the fimbrire having both ends fixed; g h, pedun- cle ending in fringed processes, probably the terminal portion of the Wolffian duct. (See fig. 401. f, and explanation.) i, 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 of the furrows formed between the plica;. The length of the fimbrite ranges from to s". 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 {Jig. 404.). The Tiiho-omrian ligament and fringes. — This so-called ligament {fg. 408.) consists of one of the fimhriae, 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 (Jig. 404. d and Jig. 405. e), be- tween the outer extremity of the ovary and the inner or lower border of the tube, it is mar- gined on either side by a row of leaflets, pos- sessing shapes as variable as those which characterise the rest of the lesser fringes. These leaflets, as well as the furrow' between them, are backed by a continuation of the peritoneal fold or mesentery, which, after enclosing the tube, here terminates abruptly on a level with its mouth, and thus is pro- duced the appearance of a ligament, whose use is simply to preserve the tubal orifice in contiguity to the ovary; but there is no FALLOPIAN TUBE OR OVIDUCT — (Normal Anatomy). reason to think that it performs, as the an- cient anatomists supposed, the office of a muscle in drawing these parts together. The lengtii of the tubo-ovarian ligament determines the distance to which the mouth of the tube can be separated from its corre- sponding ovary. This, in most instances, is sufficient to permit the tubal orifice to be easily applied over any portion of the gland of the same side ; so that from whatever part of the surface of the ovary an ovum is discharged, the reception of the latter by the tube is rendered possible by the range of motion which the mouth of the tube enjoys in relation to the ovary. The average length of this ligament, measured from its com- mencement at the margin of the ovary to the centre of the tubal orifice is 1|". Structure of the coats or tunics. — The Fal- lopian tube is composed of three coats : — viz., 1. an external investment of peritoneum ; 2. a [troper coat composed of fibrous tissue ; and 3. a mucous lining covered by epithe- lium. The tube has been already described as running horizontally within two folds of peritoneum, formed by the upper border of the lesser wing, or ala of the broad ligament, which serves also to form its mesentery, and to connect it with adjacent parts. This fold encircles the tube somewhat loosely, and con- stitutes the peritoneal coat. Betw'een this covering and the middle orpro- per fibrous coat of the tube is found a small quantity of fine and rather tough connective tissue, which serves to bind these coats to- gether. This intermediate tissue being more abundant in quantity towards the uterine end, permits a greater freedom of movement of the serous investment of the tube in this region than at the opposite or free extremity, where, in most subjects, the serous and pro- per coats cannot be separated without much difficulty. The middle or fibrous coat has been very generally regarded as containing muscular fibres, and as having a contractile power. Santorini described external, longitudinal, and internal circular fibres, and his state- ment has been reasserted by Meckel, Boivin, Velpeau, and many others. By Kdlliker, also, the middle layer of this tube is regarded as a smooth muscular coat, composed of a double layer of fibres. These statements have been called in question by Robin and Richard, who assert that there are in the proper walls of the oviduct only fibres of cellular tissue and fibro-plastic elements, but no muscular fibres of organic life. M. Ri- chard declares that it is impossible to recog- nise two distinct layers, at least they can be only artificially produced. The number of longitudinal fasciculi appears always to ex- ceed that of the transverse fibres, but these elements are interlaced in every direction, both longitudinally and transversely. The question is important, for unless we consider, with Haller, that the proper tissue of the tube resembles the cavernous body of 603 the penis and clitoris, and that, as some have supposed, the tube, when filled with blood, is capable of erection, for which conjecture there appears to be no good foundation, it is impossible, in the absence of a contractile fibrous coat, to explain those movements of the oviduct, which must necessarily occur whenever the abdominal orifice is applied to the surface of the ovary — or that peris- taltic action of the tube, witnessed by Bi- schoff in the Guinea-pig, by means of which the ova are carried backwards and forwards within the canal. See p. 611. With a view of resolving the doubts raised by these conflicting statements, I have micro- sco[)ically examined the fibrous coat of the oviduct in the human subject at different pe- riods of life, as well as in several genera of mammalia, and especially in Simia, Bos, Cer- vus, and Delphintis. With regard to these latter examples, I find the evidence of the presence of a smooth muscular layer, consti- tuting the niidtlle coat of the oviduct, more or less decisive in different genera, but the existence of such a coat was most satisfac- torily determined in Delphintis phoctena (preg- nant). Here not only were the smooth muscular fibres, collected into long bundles, easily distinguished, but they were still more distinctly shown at the broken extremities of the latter, which exhibited the characteristic fu.siform terminations of the individual fibre in such a manner as to leave no doubt as to the muscular nature of the tissue forming the principal portion of this coat, which contained besides an abundance of nuclear elements and common fibres of connective tissue. With regard to the human subject, it ap- pears to me that the assertion that the middle coat of the oviduct contains only fibrous tis- sue, may have been based upon the examina- tion of specimens taken from females advanced in life ; for, applied to such specimens, the statement is generally true, but in younger subjects, and when the proper reagents have been used, I have experienced no difficulty in finding more or less satisfactory evidence of the presence of smooth muscular fibres, provided only that a sufficiently high power, and the mode of illumination suitable to the discrimination of such tissues, were em- ployed. It must be observed, however, that the condition of this tissue is very variable. In some subjects, the greater portion appears to consist of nuclear elements which here and there are seen intermixed with fusiform fibres of greater or less length. In other instances, the tissue is more distinctly fibrillar, the fibres being collected in bundles consisting of flattened filaments with distinct fusiform ter- minations intermixed with bundles of white fibrous tissue ; while in some, and, I believe, generally in older subjects, tbe latter form of fibre, as just stated, abounds, and appears to constitute the principal portion of the middle coat of the tube. The arrangement of the fibres constituting this coat is chiefly in the direction of the 00+ UTERUS AND ITS APPENDAGES. axis of the tube. Tliis, iiuleed, a|)pears to be entirely so at the surface; but deeper towards the central canal, numerous flat l)uudles cross- ing the former at right angles are encoun- tered, and these become more abundant still nearer to the mucous membrane, although, so far as I have been able to trace them, they ilo not constitute so distinct and separate a layer as the outer longitudinal stratum. The general condition of the lining mem- brane of the tube, and its peculiar arrange- ment, having been already described, it is only needful here to explain the com[)osition and texture of this coat. This mendtrane, although commonly regarded as a mucous membrane, contains neither discoverable glands nor villi. It is composed of a very delicate pink or white soft layer, consisting of undeveloped connective tissue, mixed with numerous fusiform formative cells. This thin layer is united to the fibrous coat by a small quantity of submucous tissue, which is also found lying between the folds of membrane forming the plicae, or ridges, and serving to connect together the two layers of which they are composed. Covering this coat upon its inner surface is a thin layer of long cylindrical epithelial cells of a form pecidiar to the Fallopian tube, of which Ilenle has given a minute account.* These, which are conical or fdiform, are fur- nished with an oval flattened nucleus, and have at their broad, unattached end a dis- tinct row of cilia. These cells may be traced through the entire length of the ttdie, from the uterus to the free border of the fimbriae, where they gradually diminish in size, and, at the point of junction with the peritoneum, acquire the flattened form of the cells of pavement e|)ithelium. Under ordinary circumstances, and when the organs are healthy, the canal of the Fal- lopian tube contains only a small quantity of slightly viscid mucus. But when death has taken place during a menstrual period, the fluid is found to be replaced by blood which is usually of a dark colour, and uncoagulated. This fluid presents, under the microscope, the characters of ordinary blood, with which numerous epithelial scales, derived from the walls of the containing tube, are intermixed. Blond vessels and nerves. — M. Richard is, so far as 1 am aware, the only author who has been at the jiains to examine and de- scribe with anything like minuteness the pre- cise arrangement and distribution of the blood-vessels supplying the Fallo|iian tube. The following is bis account, the general accuracy of which I have verified by frequent in jections of these vessels. “ There exists always a special artery for the tube. S|)ringing from one of the nume- rous branches of the uterine artery, near the angle of the uterus, this vessel takes a direc- tion from within outwards, from the com- mencement of the oviduct, as far as the neighbourhood of the pavilion, describing. like the tube itself, a curve, the concavity of which looks towards the side of the ovary. The artery, which is lodged in the substance of the mesentery of the tube, takes a slightly sinuous course, jiarallel with the oviduct, and at the distance of one or two finger breadths from it. Situated in the middle of the fila- mentous cellular tissue, which exists between the two layers of peritoneum, it passes con- stantly behind the organ of Roseniniiller ; so constantly, that keeping this relation in mind, one could immediately, if the neighbouring organs were removed, distinguish the anterior from the posterior face of the lesser wing of the broad ligament. The artery is accom- panied by the two veins of the tube, and sur- rounded by very delicate nervous filaments. “ The branches furnished by this artery are lateral as well as terminal. The lateral branches are generally three in number. The first enters the inner third of the body of the tube, at a distance of three or four centi- metres from the uterus ; the second supplies the middle, and the third the outermost ex- tremity of the oviduct. These three branches before arriving at the tube bifurcate, the twigs resulting f rom which bifurcations are directed the one to the right and the other to the left to inosculate with each other. From this results a series of arches furnishing branches to every portion of the body of the tube. The innermost bifurcating branch anastomoses vr ith a branch derived from the proper artery of the uterus, so that a well-marked analogy between the distribution of the tubal artery and that of the mesentery is here observable. The terminal division is distributed to the |)avilion. It separates into a greater or less number of tortuous branches, each of which goes to supply a fringe of the pavilion ; the tubo-ovarian fringes also receive each a twig of the tubal artery. Sometimes, however, a small branch of the utero-ovarian artery, from which it is detached opposite to the external extremity of the ovary, establislies one of the anastomoses between the uterine and the utero-ovarian vessel. From the concavity of the tubal artery very small branches pro- ceed to the organ of Roseniniiller, and to the neighbouring cellular tissue.” But no adequate notion can be formed of the extreme richness of supply of vessels to this and the neighbouring organs until, after a successful minute injection, the parts have been dried and preserved in b.dsam. Nume- rous vessels which the o|)acity of the parts had previously concealed are then brought into view. They are seen running parallel with the surface of the tube, and mostly con- verging towards the fimbriae, upon and in the substance of which they lie as thickly as the pile of velvet, previously to their dis- persion into their final capillary terminations. It was probably this exuberance of vascula.” supply that led some former observers to imagine that the tube possessed an erectile tissue, a structure of which the most minute injections do not suffice to exhibit a trace. The veins, which follow the same course * Enoyclop, Aiiat. Gen. t. i. 605 FALLOPIAN TUBE OR OVIDUCT — (Functions). as the arteries of the tube, frequently an- astomose with one another by transverse branches, which serve to connect together the two principal trunks. These gather the returning blood and carry it into the ple.xus of uterine veins placed along the sides of the uterus. The lymphatics of the tube have the same common source as those supplying the rest of the internal generative organ. The nerves, which are very slender, follow the course of the arteries. They are de- rived, according to Dr. Snow Beck, from the hypogastric and aortic plexuses. Functions ot the Fallopian Tube. It has long been determined, with as much precision as the nature of the subject appar- ently admits, that the Fallopian tube performs the double office of receiving the ova from the ovary, and conveying them into the uterus, and of receiving the spermatic fluid from the uterus and conveying it in the direction of the ovary: the tube itself being, if not con- stantly, at least generally, the seat of im- pregnation ; or, in other words, the precise spot in which the material contact of the male and female generative elements takes place. These conclusions regarding the offices of the oviduct, are deducible from various ob- servations and experiments, both of a positive and negative kind, made upon mammalian animals, and the close correspondence which has been observed between these and similar observations, so far as they can be made upon the human female, leads also to the conclusion that there is little or no material difference between the mode in which these offices are performed in man and in the mammalia generally. With regard to the demonstrative evidence furnished by experiments and observations upon animals, as well as by observations upon the human subject, relative to the pre- cise offices of the oviduct in the conveyance of the ova from the ovary, the following points may be considered as established. The infundibular orifice of the Fallopian tube, together with the fimbrite by w'hich its margin is fringed, at the time of the dis- charge of ova, becomes expanded over a cer- tain portion of the ovary, the extent of the surface covered varying according to the form and proportions of the infundibulum relatively to the size of the ovary. In some mammalia, the cat for example, the infundibulum is sufficiently large to en- compass the entire ovary, so that an ovum escaping from any portion of its surface would fall within the receptacle thus provided for it, and be conveyed to the orifice of the tube, and thence into its canal. But in many animals of this class, as well as in man, the size of the infundibulum does not suffice to cover more than a portion of the ovary at any one time, half or a third it may be of the entire surface of the gland ; so that in all these cases a selection must be made of the exact spot from which the discharge of an ovum is about to take place, or else the ovum would be lost, by falling into the cavity of the abdomen. That this occasionally hap- pens is rendered evident by those cases in which the infundibulum is glued as it were to a portion of the ovary by morbid adhesion. But while the extremity of the oviduct is thus immoveably fixed, the process of ovula- tion still goes on from all parts of the ova- rian surface indifferently, so that those ova 011I3' which might happen to be discharged from the particular spot to which the tube is affixed, would by any possibility enter its Fig. 409. Ovary of a woman who died during menstruation. The coats of the ovary are attenuated in two places. Three apertures, r r, two being in juxtaposition, lead to as many Graafian vesicles from which ova have been recently discharged, escaping ap- parently into the cavity of the abdomen. The infundibulum is glued to the extremity of the ovaiy by morbid adhesion. The tube is distended by accumulated fluid; 0, ovary; i, infundibulum;/. Fallopian tube; I, broad ligament. (^Ad Fat.) 606 UTERUS AND ITS APPENDAGES. mouth, and all the rest would be lost. I have already adverted at p. 560. to such an example, and of this case a drawing is here subjoined. In this instance, three ripe Graafian vesicles had burst on one side of the same ovary, and had discharged their ova, while the mouth of the corresponding oviduct was inseparably united by morbid adhesions to the outer extremity of the gland, and was thus effectually prevented from re- ceiving any ova except such as might be dis- charged from the spot to which the tube was attached. By what power the mouth of the tube is directed to tlie particular portion of the ovary from whicli an ovum is about to be discharged remains entirely unknown, as, indeed, does also, to a certain extent, the [irecise nature of the mechanism effecting this movement. The part termed the tubo-ovarian ligament (Jig. 404. d) will at all times serve to keep the infundibulum in contiguity vvitli the ovary, but by what agency the orifice of the tube is drawn towards, and its fimbrim become ex- panded upon, tile ovary, cannot be very satis- factorily explained. These movements can only be referred to the contraction of the low form of fibre of which this part has been shown to be chiefly composed ; and although it is certain that in a great many of the in- vertebrata, a similar form of contractile fibre constitutes the sole agencj' by which their active and sometimes very ra|)id movements are effected, yet this is not commonly found to be associated with any considerable degree of movement in the higher animals. The temporary adhesion of the infundibulum to the surface of the ovary when an ovum is about to be discharged, appears to be ef- fected by the interposition of a slimy mucus, which possesses sufficient tenacity to require the employment of some slight force in draw- ing the [larts asunder, and which is furnished, probably, by those numerous minute folds or plicte so plentifully covering this portion of the tube. It was formerly supposed that this ap- position of the mouth of the tube to the ovary occurred only under tlie influence of the sexual orgasm ; an inference which was natural so long as the belief remained general that the ova were discharged from the ovary only as a consetiuence of sexual congress. But this circumstaiice admits of a modified explanation, now that the discharge of the ovum in mammalia is known to occur during the “heat,” or that period in which alone the coitus is permitted by the female. The ap- position of' the Fallopian tube to the ovary at such times is to be regarded as a move- ment providing for the safe passage of the ova to the uterus, and, in regard to time, as preceding the act of impregnation, although it might endure until after a fertilising coitus had taken place, and so the parts would occasionally' be found in such a state of apposition in an animal killed immediately or shortly after that event ; thus appearing to warrant the conclusion that the venereal orgasm had been the cause of this movement. The mode in which the ovum is expelled from the ovary has been already described at p. 560. In the form there represented, the ovum is received into, and is conducted along, the Fallopian tube ; and, on account of the interest which attaches to the earlier deve- lopmental changes occurring here, it has, |)erhaps, been more frequently examined in this situation than in anv other portion of the generative track. Barry’s tables include the particulars of ninety-three ovula, found in various parts of the tube in the rabbit, between 10 and 70 hours post coitum. Bischoff’s observations were made upon 60 or 70 ovula within the tube in the same animal, as well as upon many more in other mammalia. Several instances of the same kind have been already quoted, two of these being in the human subject; and almost every anatomical collection contains examples of the human ovum abnormally arrested and developed in the tube. In what way the ovum, after its reception by the mouth of the tube, is conveyed along that canal into the uterus, is explained by the peculiar construction of this part. The tube being lined longitudinally by slender folds which divide it into numerous capillary canals, and having every part of its inner surface co- vered by cilia, vibrating, according to Henle, in a direction towards the uterus, appears admirably adapted for the conveyance of the minute ovum downwards from the place of its formation to its seat of normal develop- ment. The peculiar form of the oviduct, which is more or less funnel-shaped, especially in the human subject, further conduces to this direction of the ovum downwards, while, in many instances, its course appears to be aided by that peristaltic action of the walls of the tube which many observers have noticed, and of which a further account will be presently given. The period of time occupied by the de- scent of the ovum through the tube does not usually exceed a very few days. This, how- ever, appears to be a variable feature in diflerent mammalia, and regarding which, even in those animals admitting of the readiest observation, it appears very difficult to arrive at definite conclusions, chiefly on account of the uncertainty belonging to the determination of the precise moment at which the ovum quits the ovary. In the bitch the ovum, after quitting the ovary, is supposed to remain in the tube susceptible of impregnation during 6 or 8 days; and its passage is probably quite completed in 10 days. In the guinea-pig the ovum makes its passage in a much shorter time, as it usually enters the uterus at the end of the third day. In the rabbit the time is nearly the same. The ovum, surrounded by a thick layer of albumen, passes from the oviduct into the uterus at the end of the third or beginning of the fourth day. While in the roe, although the time occupied is probably longer, yet, at the most, in a few days, the 607 FALLOPIAN TUBE OR OVIDUCT — (Functions). ovum, unaltered in size, as in other cases where it receives no albumen in the tube, reaches the uterus, and there, if impregna- tion has taken place, it remains four and a half months without undergoing any positive change. In man little is known accurately respecting the time occupied by the passage of the ovum through the tube. Only two instances have been recorded in which the human ovum has been actually seen in the tube (see p. 367.), with the exception of ab- normal cases. The attempt to determine this point in the human subject has generally proceeded upon a comparison of the condition of early ova found in the uterus, or prematurely expelled from it, with the last known date of inter- course or of menstruation ; but neither of these modes of calculation can afford any certain information : for it is obvious that the first can give no more than the date of insemination (as, for example, when a single intercourse has occurred), but will throw no light upon the question of the time which may have elapsed since the ovum quitted the ovary, and how long it may have re- mained unimpregnated in the tube ; while the second mode is rendered equally uncer- tain for want of more precise knowledge than we at present possess of the actual relation in point of time between menstruation and ovulation. See p. 669. The analogies which other mammalia fur- nish justify, to a certain extent, the suppo- sition, that the time occupied by the passage of the ovum through the tube in man is not materially different. But the circumstance that, in man, the periods of capacity for impregnation are not restricted to definite occasions, to the same extent that they are in brutes, greatly diminishes the value of any calculations which might be based upon these analogies. We may next examine the evidence by which it may be shown that the Fallopian tube serves, on the other hand, as a conduit for the spermatic fluid towards the ovary. That it performs this office, in addition to that of conveying the ova downwards into the uterus, is abundantly proved by the direct observations of Prevostand Dumas, Bischoff, Barry, Wagner, and many others ; whose experiments serve to show, also, to what extent the spermatozoa are capable of pene- trating within the tube, and of retaining their power of motion there. Bischoff, after repeatedly finding sperma- tozoa in active movement in the vagina, and particularly in the Fallopian tube of the bitch, though in this latter situation the movements had ceased, was so fortunate as to trace them in an animal that had been lined on two successive days, and was killed half an hour after the last coitus, not only in the uterus, but also in active motion through the whole length of the tubes, and between the fimbriae, and finally in the sac or cap- sule which the peritoneum forms around the ovary, and even upon the ovary itself. Wag- ner also found in a bitch, killed forty-eight hours after coitus, spermatozoa motionless in the vagina but active in the uterus, in whose cornua, as well as in the Fallopian tubes, their number and activity conspicuously in- creased as far as the abdominal extremit}', where they completely filled every fold of membrane, and were seen moving among the fimbrite, but none were found in the capsule or pouch that surrounds the ovary. By Barry the same fact of the possibility of the spermatozoa penetrating to the utmost ex- tremity of the tube, and even as far as the surface of the ovary, has been demonstrated. Of the latter he gives two instances ; but that the seminal fluid does not commonly penetrate so far as the ovary may be inferred from the statements of Prevost and Dumas, who could never find them in this situation, and of Barry, who, acknowledging the ac- curacy of those observers, says himself, that in seventeen out of nineteen instances in the rabbit, he was unable to detect the spermatic fluid upon the ovary, and in one of the two cases in which he had observed it there, the only evidence of the fact was the presence of a single spermatozoon. By no observer, so lar as I am aware, have spermatozoa ever been detected within the ovary of any mammal. The rapidity with which the spermatic fluid is capable of reaching and entering the tube is sometimes very considerable. Bischoff has observed spermatozoa within the oviduct of the Guinea-pig immediately after the coitus; in one instance, indeed, he traced them as far as the middle of the tube, in little more than three quarters of an hour after that event, though it had been commonly supposed that a period of nine or ten hours was requisite for the penetration of spermatozoa to the ex- tremity of the tube. The power by which the semen reaches the oviduct is partly the act of ejaculation, which may suffice to carry it to the end of the uterus, partly the jieristaltic action of the uterus and tubes, in those animals in which these parts have flexible walls ; partly, also, the movements of the spermatozoa themselves. But the cilia lining the tubes can in no way contribute to this effect, since their action would create a current in the contrary direc- tion to the ascent of the fluid. Thus it has been shown that the Fallopian tube, or oviduct, performs the double office of conveying the ova from the ovary towards the uterus, and of serving as a conduit for the passage of the spermatic fluid from the uterus towards the ovary ; and the conclusion is almost inevitable, that, by these combined operations, the encounter of the generative elements will most probably take place at some point within the tubal canal. It may, however, be objected, that since the sper- matic fluid has been known occasionally to reach as far as the ovary, impregnation may occur there ; or, on the other hand, that inas- much as this fluid must necessarily, in part at least, fill the uterus before it can occupy the UTERUS AND ITS APPENDAGES. 608 oviduct, the ovum may not become impreg- nated until after it has reached the principal cavity of the generative track. In order, therefore, to determine as nearly as possible the precise limits of the functions of the oviducts, it will be necessary to e.\- amine more particularly the evidence, which serves to show, that while the ovary is the [)art in which the ovum is formed, anil the uterus that in which it is developed ; the Fallopian tube, besides being the conductor of the ovum from the formative to the reci- pient organ, is also the seat of the second most important step in the process of genera- tion, namely, its fertilisation. Here human |)hysiology is so much at fault that it again becomes necessary to resort to the evidence furnished by e.xperiments, and observations made upon the mammalia ge- nerally. Now, one of the most remarkable circum- stances relating to the generative process in the mammalia is, that the [leriods of separa- tion of the ova from the ovary, and of their passage down the Fallopian tube, are coinci- dent with the oestrus. Bischodi indeed, has ascertained, in the bitch, that by the time the ovum has reached the uterus, or even the lower end of the oviduct, the period of heat, or desire for sexual congress, has passed away, and consequently the opportunity for impregnation is lost. In the Gninea-pig also it appears certain that the opportunity for impregnation is already gone by the time the ovum has quitted the tube, and has reached the uterus ; for the oestrus is then long passed, the coitus has long ceased to be permitted, and even the vulva is at this time again contracted. And although doubtless these conditions vary in different genera, yet a variety of circumstances, of which a more particular account will be presently given, renders it probable that the rule is general among the mammalia, that insemination shall occur coincidently with the passage of the ovum down the Fallopian tube. Next, it may be shown, by the ex|)eriments of Criiikshank, Haighton, Blundell, and Bischoff, which consisted in deligation or excision of portions of the tube, that when- ever the obliteration of the canal was com - plete, and had been effected prior to the act of copulation, fertilisation of the ovum was rendered impossible. These experiments were most satisfactory when performed on one side only of the ge- nerative organs, so as to leave free play for the natural functions of the other ; and thus the negative results obtained on the one half of the body being set off against the positive ones of the other, served to enhance the value of both. By such experiments it may be shown that mechanical obstruction of the tube, while interfering in no respect with the spontaneous separation of the ovum from the ovary, or its reception by the mouth of the tube, and descent as far as the seat of ob- struction (provided indeed that care is taken in the e.xpcriment not to destroy the vascular su|)ply of the parts), prevents the completion of the reproductive act, and stops it at this stage, by impeding the access of the sper- matic fluid to the ovum. But the results of such experiments will necessarily vary according to the time and |)lace of ap()lication of the ligature. Thus while division or deligation of the tube before, or even very shortly after, intercourse pre- vents impregnation of the ova, yet, according to Haighton, the same experiment performed sixty hours after coitus had no effect what- ever in impeding the development of the em- bryo, for in that time the encounter of the generative elements would have already taken place. But although these experiments may be infinitely varied, they cannot afford such sa- tisfactory information as may be derived from the actual examination of the contents of the tube where natural impregnation has been allowed to obtain, especially when these exa- minations have been conducted with the aid of the microscope. In this way may be ob- tained an amount of collective evidence that leaves little to be desired for the purpose of fully elucidating the history of the ovum dur- ing that brief but important period which intervenes between its quitting the ovary and its entrance into the uterus. But since an account of the development of the ovum does not come within the scope of this article, only so much of the subject will be given here as will be requisite to continue the ar- gument for the purpose of showing what is the precise part which the Fallopian tube takes in the process of impregnation. There can be no question that the mam- malian ovum, after an efficient coitus, enters the uterus in a condition differing in many important particulars from that in which it ordinarily quits the ovary. And although a certain amount of variation is perceptible in regard to the actual changes experienced by the ovum in difierent species, during its pas- sage through the tube, yet so constantly are the main features preserved, that the obser- vations made upon any one species will ge- nerally serve as a type of the rest, and cer- tainly the aggregate of these observations, agreeing closely as they do with one another, render the conclusion in the highest degree probable, that changes not very different from these occur also in the ovum in man. Barry asserts that “ there is no condition of the ovum, uniform in all respects, which can be pointed out as tbe particular state in which it is discharged from the ovary.” Ne- vertheless the ripe ovum which is about to be expelled, or one which has been just discharged, presents certain well-marked cha- racteristics, of which the following are the most important. The ovum is closely invested by a layer of nucleated cells. These form a portion ot the granular membrane or lining of the Graafian follicle in which it is imbedded, and when the ovum is discharged from the follicle, as described at p. 560., a portion of these gra- 609 FALLOPIAN TUBE OR OVIDUCT — (Functions). nules is carried with it into the mouth of the Fallopian tube. In ova which are not quite ripe, these nu- cleated cells are round, but during the oes- trus, in the riper ova, the cells become elon- gated and fusiform, having their pointed ends attached to the zona peliucida or bounding membrane of the ovum. They present a glassy swollen aspect, by which the fully ripe Fig. 410. Ripe ovum from the ovary. Guinea-pig. After Bischoff.) ova acquire an appearance of being sur- rounded by rays. This change occurs in most mammalia, as the dog, rabbit, sheep, rat, roe, and kangaroo. It is characteristic of the mature ova, and may be regarded as a certain sign of their ripeness. Corresponding with this external alteration in the appearance of the ovum, are certain internal changes, of which the chief is the disappearance of the germinal vesicle. This indeed seems to be an almost constant phe- nomenon throughout the mammalia, though, as to the precise mode, or even time, of dis- appearance of this important constituent of the ovum, observers are by no means agreed. By Barry it was considered, after close ob- servation, that the vesicle was not dissolved nor ruptured, as many now suppose, but that it became lost to observation by retiring to the centre of the ovum, where it was changed in character by an internal process of cell de- velopment. These changes, external and internal, are the precursors of impregnation, and charac- terise the ovum shortly prior to and at the period of its quitting the ovary. Arrived within the Fallopian tube, the first alteration which the ovum experiences is the stripping off of the ray-like appendage of nu- cleated cells with which it quitted the ovary. This change results apparently from a burst- ing and diffluence of these cells, now no longer capable of serving any useful [Uirpose; Swpp. for the conjecture that they might furnish materials for the construction of the chorion has not been supported by any direct obser- vations. On the contrary, numerous obser- vations of Bischoff show that this process of freeing the ovum from its surrounding layer of cells, takes place very soon after its en- trance within the tube, and generally in the upper third. Fig. 411. T/ie ovum on first airiving in the Fallopian tube. The ray-like appendages are nearly stripped off. {After Bischoff.) a, zona peliucida ; b, granular bodies between tlie zona peliucida and yelk. Rabbit. And now, if the coitus does not obtain, and no contact of the generative elements occurs, the ovum perishes ; observations at least relative to its further fate are wanting. But should the ovum have become fertilised, then a noticeable series of changes takes place, of which the following are the most im|)ortant. The zona peliucida, or transparent bound- ing membrane of the ovum, having been freed of its external granular investment, the entire ovum presents the condition represented in figure 412. Deprived now of all encum- brance, the surface of the ovum is in a condition eminentl}' favourable for the pas- sage through it of the spermatozoa, which penetrate readily that soft outer coat, and thus gain admission to the yelk. The fact of the penetration of the outer coat of the ovum by the spermatozoa, which has been so often asserted and denied, may now, after much controversy, be considered as established. In the mammalian ovum, this passage may take place apparently through any portion of the outer coat, just as it does in the ova of amphibia, and not through a special pore or microphyle, such as exists in the ova of osseous fishes. Following this act of penetration occurs a change which apparently affords the first distinct evidence that the power of the s[)er- matozoa has been efficiently exerted upon the ovum. The yelk, which had previously completely filled the zona, is observed to have become contracted, so that an inter- space is left between it and the zona, termed by Newport, who has carefully watched its formation in the ova of amphibia, the “ re- spiratory chamber.” Such a retiring of t!\e yelk, so as to leave an interspace between R u 610 UTERUS AND ITS APPENDAGES, the latter and the zona pelludda, vvhiclt in- terspace is filled by a transparent fluid, has been noticed in many maininalia, as the Guinea-pig, rabbit, &c. Fig. 412. The omim a little Ttiore advanced in the tube. {^After Bischoff.') The surface is perfectly smooth. Spermatozoa have penetrated the zona pellucida. The respira- tory chamber is formed between the latter and the yelk. The rotation of the yelk has commenced, as indicated by the arrows. The granular bodies ap- pear preparatory to tlie segmentation of tlie yelk. Several of these stages are seen commencing in the preceding figure. Kabbit. This change is preliminary to another oc- currence, which has been observed in the ova of many animals, both vertebrate and invertebrate, viz. the rotation of the yelk within the interspace just described ; — a ro- tation which is effected by the aid of cilia clotliing the surface of the yelk. About this time may be observed one, or ]rerhaps two, small granular bodies, whose formation has given rise to many and varied s[)eculations regarding their signification and use. They occupy a portion of the space between the yelk and zona pellucida, and appear to be common to the mammalian ovum and that of other classes. The most [)robable supposition regarding their use con- nects them with the division or cleavage of the yelk which follows their appearance. Whatever doubts may be entertained as to the dependence of the phenomena already described upon a preceding act of impregna- tion, all question is set at rest at this point, by the direct experiments of Newport, who Fig. 413. The ovum still more advanced in the tube. (^Afier Bischoff.) The lirst stage in the segmentation of the yelk has taken place. Rabbit. ascertained beyond doubt, that segmentation of the yelk is the result of impregnation alone, and that it never takes place in the unim- pregnated ovum. This segmentation of the yelk consists in a spontaneous cleavage of that body, at first into two, and then into four, equal parts; the process of division continuing in geometric progression until the whole is broken up into a mass of finely nucleated particles, between whicli the original sperm-force is probably equally divided. Segmentation of the yelk of the mamma- lian ovum has never been observed in its commencing stages anywhere but in the tube. The extent to which it proceeds before the ovum quits the oviduct to enter the uterus appears to vary in different species. Bischoff never saw more than four yelk-divisions in the ovum of the Guinea-pig by the time that Fig. 414. The ovum from the lower or uterine end of the Fallopian tube. (^After Bischoff) The yelk exhibits four divisions. Rabbit. it had reached the lower portion of the tube ; and it is probable that a further division into eight parts occurs in the extreme end of the duct, since, in the next condition of the ova found in the uterus, the yelk exhibited 12 — 16 divisions. The oidy remaining change in the condition of the ovum during its residence in the ovi- Fig. 415. The addition of a layer of albumen in the lower por- iioH of the ttibe — (observed only in, the rabbit.) (After Bischoff'.) The yelk exhibits eight divisions. ! FALLOPIAN TUBE OR OVIDUCT — (Functions). duct, which it is necessary here to notice, is the addition, sometimes, of a thick layer of albumen around the zona pellucida, which is formed upon it in the middle and lower por- tions of the tube. But this is certainly not a constant, and apparently not even a common occurrence. It occurs in the rabbit, but not in the bitch, Guinea-pig, or roe. These are the principal and more obvious changes which the ovum experiences in its passage down the Fallopian tube until it enters the uterus. So regular is the order with which they succeed each other that particular portions of the tube may be as- signed as the seat of each occurrence. Thus the first, or u[)per third of the oviduct is appropriated to the reception of the ovum, which, soon after quitting the ovary, is here deprived of its adventitious covering of nu- cleated cells, and is thus prepared for the full operation of the spermatozoa, whose active movements in this part of the tube have been frequently noticed. Here also spermatozoa have been frequently seen upon, and even within, the ova ; and here the first changes characteristic of the commencing operations of the sperm force, such as the formation of the respiratory chamber, and rotation of the yelk, may be noticed. In the middle of the tube the ova commonly exhibit still more decided evidences of impregnation. The cleavage of the yelk has already com- menced, and one or more granular bodies occupy the space between it and the zona. The ova found in the lower third, except those which may be destined to perish, al- ways show unmistakable signs of impregna- tion, of which the segmentation of the yelk, now advanced to the production of 12 — 16 divisions, is the most expressive. If the views of Bischoff be correct, it is in the upper third, or at farthest in the middle of the tube, that impregnation must occur, unless indeed it takes place at the ovary. For in the lower end of the tube the more definite developmental changes of the ovum occur, or otherwise the ovum perishes. In the dog and Guinea-pig, by the time the ovum has reached this spot, the oestrus is past, and the animal wdll no longer permit the coitus.* Connected apparently with some of the foregoing steps in the process of generation, though it does not appear precisely with which, is a phenomenon described by Bis- choff as occurring in the Guinea-pig. Several * Pouchet (L’D^mlation Spontanee) places the seat of impregnation lower down in the oviduct. He asserts that it is only about the middle of the tube, or more particularly in its lower portion, and even in the cavity of the uterus itself, that the material contact of the ova with the spermatozoa can occur. And he regards the passage of the semen as far as the extremity of the tube, and its arrival at the ovary, as an “ excessively rare ano- maly.” But these statements are based upon ex- aminations directed only to the detection of the presence of spermatozoa in the oviduct, and are not , connected with microscopic observations of those developmental changes in the ovTim, which are in- disputably the results of impregnation, and of which an account has been given in the text. Oil times Bischoff had the good fortune to ob- serve with a lens, and also under the micro- sco]ie, a peristaltie action in the walls of tlie oviduct, by which the contained ova, visible through them, were moved backwards and for- wards. The ova appeared to be surrounded by a transparent fluid, in which they floated. Now, such an observation is interesting, when viewed in connexion with two circum- stances, specially observed and proved by Newport, namely, that in the artificial im- pregnation of the ova of amphibia, although the process of impregnation is commenced at the instant of contact of the spermatozoa with the ova, yet a certain duration of contact is essential to its completion. And further, tliat although an exceedingly minute quantity of spermatozoa suffices to impregnate the ovum, yet impregnation takes place more tardily when the number is extremely limited than wlien the number is in full abundance ; while when the quantity is reduced below a certain amount, or the duration of contact is limited, then the phenomenon is incomplete, and partial impregnation, evidenced by imperfect segmentation of the yelk, and arrest of the further stages of development, is the in- evitable result. Since, then, it cannot be supposed that a less perfect or complete contact of the ova with the spermatozoa is needful to their im- pregnation in the higher than in the lower vertebrata, there seems to be good ground for conjecturing that this peculiar peristaltic movement in the walls of the Fallopian tube, which has been noticed also by other ob- servers, may have for one of its objects the more perfect commingling of the two gene- rative elements, the spermatozoa and the ova, which, proceeding as they do in opposite di- rections, and encountering each other in some portion of the canal, would thus be carried backwards and forwards, and thus a certain permanence of contact, such as Newport has shown to be necessary in the amphibia, would be insured to them. And this supposition may he further strengthened by the reflection that while an onward movement in either di- rection would serve for the conveyance of each element singly along the tube, a back- ward and forward motion alternating could onl}' retard either or both processes, and that there could be only one apparent advantage in such retardation, namely, the retention of both elements for a longer or shorter time in permanence of contact. To sum up the offices of the Fallopian tube, the following may be said to have been with certainty ascertained to belong to that division of the generative organs : To re- ceive the spermatic fluid from the uterus and convey it upwards through the entire canal, and as far sometimes as the ovary ; To receive contrariwise the unimpregnated ova, as they are discharged from the ovaiy, by means of its expanded open mouth, which in these cases, where the entire ovary cannot be grasped, is guided, by a process hitherto unexplained, to select and apply itself to that R R 2 G12 UTERUS AND ITS APPENDAGES. liarticiilar spot from which the ripe ovum is about to be expelled ; to convey the ovum in a direction opposite to tlie course of the fertilising fluid, so as to ensure the meeting and commingling of the generative elements, an event to which the limited calibre joined to the peristaltic action of the oviduct probably in a great degree contributes ; to afford pro- tection to the ovum during that brief sojourn in wliich the first effects of fertilisation are manifested upon its constituent i>arts ; to aid probably in certain changes which are operated upon the surface of the ovum, con- sisting first, in all cases a|)parently, in a strip- ping off of the adventitious covering with which the ovum is invested on entering the tube, and secondly, in some instances, in the addition of certain materials which in- crease slightly the bulk of the ovum ; and lastly, in transmitting onwards the ovum, so altered and prepared for more complete de- velopment, to the cavity of the uterus, or in conveying away those which, for want of impregnation, are destined to perish. In reference to these conclusions regarding the offices of the Fallopian tube, which the present state of physiology appears to war- rant, the question here naturally arises, how far they are applicable to the female of man, or to what extent her case may be viewed as exceptional on account of certain differ- ences in her organisation and habitudes. (fne of the most observable of these dif- ferences is the absence of that marked dis- tinction of periods alternating with each other, such as are shown in a greater or less degree in the females of most mammalia in regard to the activity of the sexual functions. That these alternating periods of desire and aversion to the coitus are strictly sig- nificant of correspomling temporary states of |)hysical capacity and incapacity for concep- tion, is placed beyond doubt, by the results of examination of the internal organs and their contents at these respective periods. In those animals in which the oestrus re- turns at short intervals, the male generally remains potent at all times. The temporary incapacity is on the side of the female, and occurs in the intervals between the successive acts of ripening and discharge of the ova from the ovary, together with their passage down the tube. It has been shown that during these events only will she receive the male, and therefore, on that account also, is con- ception then only possible. This circumstance is rendered more striking in animals in whom this interval is longest, as in the roe-deer, where the oestrus returns only once annually, and in whom the capacity for procreation is limited to a few weeks, for the reason stated by Bischoff, that then the ovary contains ripe ova and the testes ripe semen, ami at no other time. But in the human female, whatever views may be entertained regarding the connexion of a separate act of ovulation vvith each menstrual periotl, it is certain that here a marked astrus is wanting, and that although the capacity for impregnation is apparently greatest about the times of menstruation, yet, notwithstanding the assertions of those who maintain that there is a perpetual recur- rence of temporary incapacity for procrea- tion, there is no period at which the healthy human female can be shown to be positively incapable of conception during any part of menstrual life. It may, however, be asked whether the oc- casional occurrence of impregnation during an intermenstrual period, at a date more distant than usual from the last menstrual act can be explained consistently with a strict interpretation of the law that menstruation and ovulation are contemporaneous acts. This appears to be reconcilable vvith the circumstance that although these acts, so far as observation has yet gone, are very fre- quently and perhaps usually coincident, yet exceptionally an ovum may be emitted during an intermenstrual period, the ripening and not the time or the act of emission of the ovum being probably the essential feature, or that the ovum, supposing it to have been emitted from the ovary at the time of men- struation, may possibly remain in the tube susceptible of impregnation longer in the human female than in the mammalia gener- ally, or may even be impregnated after reach- ing the uterus. * That the Fallopian tube in the human subject is, occasionally at least, the seat of impregnation, is demonstrated by the occur- rence of the tubal form of extra-uterine ges- tation ; while the numerous examples already quoted of other mammalia render it highly probable, by analogical reasoning, that this is the normal seat of that function in man. That the first encounter of the generative elements may also take place either in the uterus or upon or even within the ovary, is plainly possible. That it occurs sometimes at or near the ovary is evidenced by the varieties of extra-uterine gestation termed ovarian and ovario-tubal. It is even possible that, in some of these, insemination may have been so coincident with the spontaneous opening of the Graafian follicle, that the spermatozoa, penetrating further than usual, may have reached the ovary at that precise moment when a passage had been prepared for the ovum, and some may have actually passed into the follicle and have impregnated the ^ ovum there. No argument certainly can be opposed to this on the ground of physical impossibility -j- ; while, on the other hand, it is also conceivable that impregnation may be ' delayed until after the ovum has entered the ' uterus, as in the case just suggested of a i fertilising coitus occurring later than usual | after the menstrual period ; but I am not ■ aware of any good anatomical or physiological i reason for regarding the uterus, as by pre- * These points are more fully considered under ^ the head “ Menstruation,” p. (!6y. , I t See the argument regarding the anatomical I evidence for this form of gestation at p. 58(5, | 613 FALLOPIAN TUBE OR OVIDUCT — (Development). ference, tlie seat of normal impregnation ; while such a view is opposed to those nu- merous observations upon the mammalian ovum generally, which show, that before the ovum quits the oviduct, the developmental changes in it are already advanced many stages, while, by the time that it arrives at the uterus, the opportunity for impregnation has already passed away for that occasion. Development of the Fallopian Tube. Whatever difference of opinion m.ay exist regarding the origin of the excretory duct of the male generative gland, there appears to be no doubt, that in birds at least the correspond- ing part in the female has its commencement in a structure which, as soon as it can be recognised as a distinct tube, is altogether separate from the Wolffian body. 'I'liis is called after its first observer, tne duct of Miiller* {fig- -100. g). The mode of origin of this duct has been already partly described in the account which has been given of the formation of the Paro- varium (p. 591.). Its development may be most conveniently traced in birds, where it can be easily shown that the oviduct is not a metamorphosis of the excretory duct of the Wolffian body, but may be distinguished lying near it, in the form of a tolerably thick tube ; which at first ends in a closed extremity, but afterwards exhibits a wide orifice. It runs along the outer side of the Wolffian body, while its infundibulum, which is soon distin- guishable, extends beyond and is entirely se- parate from that body. The oviducts a|ipear from the first in the form of white cylinders on both sides. They do not grow from below upwards, but are formed in their entire length from the com- mencement ; nor are they constructed out of a membranous lamina, rolled togetlier, as Meckel supposed ; but are in the beginning solid, and become gradually hollowed out into a tube. In this way also is formed the infun- dibular opening of the tube into the abdomi- nal cavity. Two oviducts exist originally in all birds, but as in this class the right ovary shrinks and disappears, so the right oviduct becomes lost, by gradually contracting and shortening from above downwards, f In mammals, before the distinction of sex becomes apparent internally', there is seen, running along the Wolffian body of each side in every embryo, a duct, which, according to Muller, may represent either a vas deferens, or an oviduct. These ducts lie upon opposite sides of the germ glands, which may become afterwards testis or ovary. Soon afterwards the internal organs begin to exhibit a distinction of sex. This is indi- * See IMliller’s Bildungsgeschichte der genita- lien. Diisseldorf, 1830. t Prof. Quekett has pointed out to me,in the col- lection of the Royal College of Surgeons, a remark- able preparation by Mr. Tegetmeir, in which the right oviduct is developed in the common fowl. cated in the future male by the duct, which runs along the outer side of the Wolffian body, sending off a white granular projection, extending towards the testis, which is met by a similar projection, given off by the upper end of the testis, and these two by their union form the rudiments of the epididymis. So that in the male mammal a new connexion is established between the duct, which after- wards becomes vas deferens, and the testis, without any agency from the Wolffian body, but through the development of new material. In the female these projections are wanting, both from the excretory duct and from the ovary. The latter remains attached only to the Wolffian body by a simple fold. The up- per end of the duct, which runs over the Wolffian body, [irojects somewhat beyond that body inferiorly, and terminates here in a glo- bular swelling, in which an aperture is formed at a later period. As the Wolffian body becomes atrophied the portion of the duct which takes its course over it, and which was previously straight, begins to be tortuous in the male, while in the female it remains straight, but becomes w'ider. Out of corresponding jiortions of the duct are formed, in the male, the head of the epi- didymis, and in the female the infundibular emi of the tube, while the inferior free por- tion of the duct, after it has quitted the Wolffian body becomes converted, in the male, into the vas deferens, becoming at the same time more and more elongated ; but in the female the corresponding portion of the duct is transformed into the inferior division of the tube, or into the cornu of the uterus.* In this stage of its development the inci- pient Fallopian tube is only beginning to be recognisable. It circumscribes the diminish- ing Wolffian body on its outer side in the form of a bow. Above the superior opening extends beyond that body, while below the short free portion becomes conjoined with that of the opposite side to form a single tube. These ducts have throughout the same breadth up to their union with each other. A division of the tluct into uterus or cornu, and narrower Fallopian tube, is still nowhere perceptible, and the place of this latter divi- sion is only as yet indicated by the addition of the substance which afterwards becomes ligamentum rotundum. Between the oviduct and the ovary lies the atrophied Wolffian body of a dirty yellow colour, in part surrounding the ovary ; but notwithstanding this conti- guity the tubuli of the Wolffian body form no union between the Fallopian tube and the ovary. The duct, or future Fallopian tube, which had previously preserved a perpendi- cular direction, now takes, with the rest of these parts, a more sunken position. But it still lies close to the Wolffian body, from which it is separated by a narrow fold of peritoneum. * The researches of Kobelt upon this subject have been already explained under the head of development of the Parovarium. R R 3 CI4 UTERUS AND ITS APPENDAGES. Fiff. 416. G e.mto-urinary organs of a foetal sheep. (After J. Muller.) a, kidneys ; 5, ureters ; c, ovaries ; cl, ‘Wolffian bodies ; e, uterine cornua and Tallopiau tubes ; f, infundibular end of the tubes ; g, middle portion of the uterus. In older female embryos the Fallopian tubes, now more completely formed, are tliicker and exhibit a somewhat undulating outline. The F?ff. 417. Internal generative organs of a foetal deer. {After J. Miilier.) a, middle portion of the uterus ; cornua; c. Fal- lopian lubes or oviduct; d, ovaries; e, remains of the Wolffian bodies. Wolffian bodies, much reduced in size, may be found lying in a duplicature of peritoneum, between the ovaries and the oviducts. The iiiferior portion of tlie latter becomes wi- dened,-and the division between the tubes and the horns, or cornua, of the uterus is established ; although the tube still remains relatively very broad, even up to its abdomi- nal end. In the human subject the opportunities for observation upon very early embrj'os being of not very frequent occurrence, the foregoing changes have not been so accurately traced in the first stages as in the embryos of birds and mammals ; but all the examina- tions which have yet been made lead to the conclusion that the Fallopian tube has its origin in a duct similar to that already described. This, with the rest of the in- ternal organs, is sufficient!}' developed by the third month of utero-gestation to leave no longer any douht as to the sex. By this period the oviducts have nearly acquired that horizontal position which, from the fourth month onwards, becomes a more marked cha- racteristic. In embryos of tbe fourth month the tubes run parallel with the now horizon- tally placed ovaries, whose elongated form corresponds with the tube in the greater por- tion of its length. By the end of this month the abdominal end of the tube is seen to be wide open, and traces of the fimbriae are dis- coverable in its already fringed margin. The lower ends of the tubes are still not so com- pletely united but that an indentation is per- ceptible at their point of junction, giving evidence of the still bi-corned condition of the uterus. From this period onwards the proper structure of the tube wall appears to grow with greater rapidity than the fold of peritoneum by which it is invested ; so that in advanced embryos, and in the foetus at term, the ovi- duct is usually found of a tortuous or serpentine form, its windings being easily dis- tinguishable through the peritoneal sheath. The tube now much exceeds the ovary in length, and its infundibulur end is beautifully margined with delicate fimbrias {Jig. 418.). Fig. 418. Uterus and appendages of human foetus at term. {After lUcliard.) d, pavilion of the left side ; a, the same of the right side (below it, in this specimen, is the remark- able variety of two separate accessory pavilions h and c) ; d. Fallopian tube, exhibiting numerous sinuosities in its outer half; f, round ligament; e, ovary. AitNORMAL Anatomy of the Fallopian Tube. Defect and Inqrerfecl Development. — Ab- sence of the Fallopian tube is of infrequent occurrence, and is usually observed in cases where there is a coincident deficiency of the uterus or ovary.* But when the two latter * Meckel, Handbuch der Patholog. Anatomic, B. I. 615 FALLOPIAN TUBE OR OVIDUCT — (Abnormal Anatomy). organs are perfectly formed it is exceedingly rare to find a deficiency of the oviduct. The oviduct may be deficient either upon one or both sides. Heusinger * has recorded an example of deficiency of the ovary and Fallopian tube of one side. Chaussierf met with a remarkable ex- ample of a woman who, notwithstanding the absence of one ovary and tube, and even of one side of the uterus, bore ten living children ; and whose death shortly after her last con- finement afforded him the opportunity of ascertaining this peculiar condition of the parts. After the observations which have been made regarding the function of the Fallopian tube, it is hardly necessary to observe here that deficiency of both tuljes will be neces- sarily productive of permanent sterility ; al- though absence of the tube of one side, as in the case of Chaussier, just quoted, need not entail any such consequence. Unusual shortness of the tube and the absence of the fimbriae have been also ac- counted as causes of sterility ; but the former, if associated with a very short ligamentum ovarii, would have no such effect, and could be only accounted a relative deformity when the ovary is placed at an unusual distance from the uterus, so as to be beyond the grasp of the infundibulum ; while the latter pecu- liarity, as already shown, may be merelj’ the result of age. Peculiarities of Construction. — Several Pa- vilions on the same Tube. — M. Richard, to whose researches regarding the Fallopian tube reference has been already made, has pointed out a previously unobserved condition of this part. In examining the appendages of the uterus in thirty women, he met with no less than five examples of this singular formation, which he thus describes : “ At a distance varying from several millime- tres to 2 or 3 centimetres behind the normal pavilion, are observed upon the course of the tube one or more accessory pavilions, formed like that which terminates the oviduct, of a mucous membrane divided into fimbrim. When the fringes of this pavilion are floated under water, they are observed to be pierced by an aperture leading into the canal of the tube ; and a probe introduced into this orifice may be made to escape either by the ostium abdominale, or by the ostium uterinum, ac- cording to the direction in which it is passed. Thus, then, the canal of the tube can, in certain cases, open into the cavity of the peritoneum by several distinct orifices.” The first of M. Richard’s cases occurred in an adult, and is represented in fig. 408. “ There is a normal pavilion of somewhat irregular form, and below it, at several milli- metres distance, a small opening, surrounded by two small fringes, covered on their inner sur- face by mucous membrane ; while the serous membrane terminates abruptly on their outer surface as in the true pavilion. A probe introduced escapes by one or other orifice indiscriminately.” The second example {fig. 418.) occurred in a foetus at term. The tube of the left side terminates in a single pavilion, but that of the right, besides its terminal pavilion, ex- hibits also two little secondary pavilions, com- municating each by a special orifice with the canal of the tube. But the most interesting example is that shown in fig. 419. from a woman who aborted Fig. 419. Extremity of Fallopian tube Qiumari) having two pavilions. {After Richardl) a a, fimbria: of the terminal or normal pavilion, exhibiting an unusual richness of folds; bb, accessory pavilion in the side of the tube, having two distinct orifices separated by a valvular fold; cc, a bristle introduced at the terminal pavilion escapes by one of these lateral orifices, but cannot be made to pass out by the other, or to enter the uterus on account of the valve; dd, a second bristle introduced from the lower end of the tube escapes by the other orifice of the accessory pavilion, but cannot be made to pene- trate as far as the terminal infundibulum. * Heusinger’s Zeitschrift fur die organische Phy- sick, II. 2. t Busch. Das Geschlechtsleben des Weibes, B. IV. p. 348. at the sixth month. The terminal pavilion, represented here of the natural size, exhibits a richness of fringes and folds rarely seen. R R 4 CIO UTERUS AND ITS APPENDAGES. Below this large pavilion is another, the fringes of which are large and floating. This abnormal pavilion exhibits two orifices se- parated from each other by a valve, which, being prolonged into the canal of the tube, interru|)ts all communication between that part of the canal placed above and that below it. The valve is formed of a fold of mucous membrane. A probe introduced by the ab- dominal orifice of the tube escapes by one of the two orifices of the supernumerary pa- vilion, whilst one passed from the uterus appears at the other orifice of the same accessory pavilion. M. Richard points out a very important influence which these abnormal openings may have upon the functions of the oviduct. An ovum having entered the terminal pavilion, if while endeavouring to gain the uterus it is directed along the wall of the canal which is opposite to the accidental opening, it will reach the uterine cavity ; but if, instead of cour.sing along the wall opposite to the so- lution of continuity, it descends along this wall itself, then it will almost inevitably escape by this abnormal orifice, and will fall into the peritoneal cavity. Now, if this ovum has not been fertilised, nothing remarkable will ensue upon its escape into the peritoneum ; but if the contrary, then it is possible that the fertilised ovum having escaped from the canal which should conduct it to the uterus will give rise to an abdominal pregnancy. Displacement of the Fallopian Tube. — This is, perhaps, one of those conditions of parts which would be the least likely to be detected during life, and it may on that account have been often overlooked. It is of necessity associated with displacements of certain other organs, whenever such displacements occur ; as, for example, with prolapsus inversion and retroversion of the uterus. In extreme pro- lapsus or procidentia uteri the tubes, along with the ovaries, are carried down and occupy a position on either side of the prolapsed organ, and between it and the walls of the inverted vagina, while in inversion the tubes are contained in the pouch formed by the reversed uterus.* In this latter case the rela- tive situation of all the parts is so altered that the uterine orifices of the Fallopian tubes may be sometimes discovered as forming oblique openings in the upper part of the va- gina, j But displacement of the Fallopian tube may occur alone, and constitute a true her- nia. Such an occurrence is recorded by M. A. Berard.f In this case the displacement took the form of a crural hernia, which was at first reducible, but after gradually increasing in size it could be no longer reduced. As fluid was distinguishable within the hernial sac a puncture was made, but peritonitis en.sued, followed by death ; and upon exami- nation it was found that the sac contained nothing but the hypertrophied Fallopian tube. * See Jiffs. 470 and 471. t Patholog. Museum, Roy. Coll, of Surg. Lond„ No. 2C54. J Revue Mddicale, Mai 1839. Meissner* has collected three other cases of hernia of the tube, one of which was con- genital. These are all instances of inguinal hernia of the tube. In the “Journal flir Geburtshelfer-j- ” an instance of displacement of another kind is recorded. The left Fal- lojnan tube had escaped through a rent in the walls of the vagina near the os uteri, and descended as far as the labia, so that the fim- briae could be easily distinguished during life. The most common displacements of the Fallopian tubes are those which result from adhesions consequent upon inflammation of their peritoneal coat. Such adhesions con- stituted by bands or extensive surfaces of false membrane, tie down the tubes to surrounding parts, and in most instances effectually pre- vent the performance of their pro[>er func- tions ; as where the tubes are adherent to the uterus, the sides of the pelvis, or the bladder or intestines. But the union is most com- monly found to have taken place between the extremity of the tube and some part of the surface of the ovary, so that these are inseparably united together (y%.409.),and very i frequently in some abnormal position (^g. i 420.) ^ ^ ^ I Obliteration of the Fallopian Tube. — In ij advanced life a natural contraction of the j tube takes place, and the fimbriae also di- ,j minish and lose their luxuriance of form ; but i it frequently happens that, independently of these natural changes, and even at an early I period of life, the tubes arc found nearly or | entirely obliterated. Such obliteration may ! be occasioned by tumefaction of the lining j membrane of the tube, or by a collection of | inspissated mucus in some part of the canal ; or the entire calibre of the tube may be ob- i| literated by cellular formation (atresia tuba:). | Occasionally calcareous concretions have j been found obstructing the tube ; and the i same result has been produced by growths ot a malignant kind. The occlusion, however, is generally con- ; fined to the abdominal end of the tube. In | these cases, usually, the fimbriae are destroyed, I the opening into the abdomen is completely closed, and the tube ends in a blunt cul-de- sac. Such a condition of parts is generally associated with an enlarged and tortuous state of the tube, the walls of which are usually thickened, and its canal filled with fluid. In such cases the obliterated end of the tube Hi may remain free and unattached, but it is far , more often found united inseparably to the ovaiy. This junction of the tube with the ovary by artificial adhesion is the most com- . mon of all the morbid conditions of the ovi- duct. It has been supposed by some to be | the result of certain libidinous habits and j practices ; but this conjecture is not supported | by any statistical evidence. The explanation | given by Rokitansky, that this form of adhe- , sion results usually from an extension ot ca- i| * Die Frauenzimmer Krankheiten, Leipzig, 184 o, I Bd. II. p. 203. I f Frankfurt u. Leipzig, 1787. I FALLOPIAN TUBE OR OVIDUCT — (Abnormal Anatomy). G17 Fi^. 420. The Fallopian tubes tied down by Jalse membranes to the ovaries and adjacent structures. After Hooper.') a, uterus ; b. Fallopian tubes (the infundibula obliterated) ; d, ovaries ; e e, bands of false membrane. tarrlial inflammation along the lining mem- brane of the tube, which, spreading to the fimbriated extremity, gives rise to peritoneal inflammation in the vicinity of the orifice, so that the free terminations of the tube are bound down to the adjacent parts, seems to offer the truest explanation of the nature and origin of this peculiar condition of the parts. See Jig. 409. In some of tliese cases, however, there ap- pears to have been something more than a mere process of exudative inflammation at work. The parts upon examination appear to have become blended by a combined pro- cess of absorption of the fimbriae, and at the same time of firm agglutination of the infun- dibular base to the surface of the ovary ; so that it may be difficult to find any precise line of demarcation betw'een these parts, except that which a difference of colour may furnish. Hypercemia or congestion of the tissues of the tube is very commonly observed. It is apparently a normal state during healthy menstruation, but may be regarded as morbid when associated at other times with deep congestion of the uterus and ovaries. A state of hyperaemia of the tube has been found associated with effusion of blood into its canal, and the escape of a portion of this fluid into the abdomen through the infundi- bular orifice. Hyperaemia of the tube occurs as a semi- normal condition in cases of tubal pregnancy. Inflammatory lesions of the tube may pre- sent the characteristic conditions of acute or of chronic inflammation. The former is com- monly seen in cases of puerperal metro-peri- tonitis, where the inflammation attacking usually the uterus first has extended to the ovaries and tubes. “ The tubes are tumified and infiltrated ; their mucous membrane is variously reddened, discoloured, excoriateil, softened and everted at the fimbriated ex- tremity. The passage of the tube is dilated, especially at its outer end, and filled with various products, purulent and sanious fluids, and in uterine croup with coagulable lymph, assuming the shape of a tubular concretion, the exudative process having extended from the uterus to the tube.” * But more commonly the traces of inflam- mation are found in the peritoneal coat, which highly congested and covered by flakes of lymph, partakes in the general inflammatory condition of the adjacent serous surfaces. In the non-puerperal state, or as a sequel of puerperal affections, inflammation usuallv takes the form of catarrh or blennorrhoea of the mucous membrane of the tube. The usual evidences of such an affection are, a certain amount of tumefaction of the mucous lining, with thickening of the delicate plicte covering it, and dark congestion of the capil- lary vessels. Within the tubal canal are found collections of mucus variously coloured, being sometimes viscid, or occasionally cream-like, yellow and purulent (flg. 421.). The chronic inflammations of the serous coat of the tube, which result in various ad- hesions of this part to surrounding structures, have been already noticed. Collections of fluid ivithin the tube result from a combination of two or more of tiie foregoing conditions. These fluiils consist of blood, menstrual fluid, mucus, serum, or pus, and sometimes of these in various states of ad- mixture. Collections of blood, or of a bloody fluid with- in the tube, are occa.sioned by hypermmia of * Eokitansky. Patholog. Anat. Vol. II. p. 32G. 618 UTERUS AND ITS APPENDAGES. the tube- walls, whose over-clistenJed capilla- the tube are patent, the fluid may escape into ries relieve themselves by sanguineous elTu- tlie uterus, or possibly, by the infundibulum, sion. In such a case, if both the orifices of into the cavity of the abdomen. Of such Fig. 421. The Fallopian tubes thickened bp inflammation, and distended by collection of fluid. (^After Hooper.') a, uterus ; b, distended tubes ; c, thickened lining of the same ; d, round ligament. elfusions there are many examples on record. Or should tlie abdominal end of the tube be closed in the manner already described, and should the uterine end also be temporarily obstructed, as, for example, by slight conges- tion of the mucous lining at this point, then the blood, having no outlet, will continue to accumulate within the tube, and a distension of the parictes, more or less considerable, will result. But all collections of blood within the tube are not necessarily the result of haemorrhage. The menstrual fluid has been frequenly ob- served to have accumulated here. And these accumulations may occur under various cir- cumstances. Thus, in the case of imperforate hymen, when the menstrual function has been established for some time, this fluid, after col- lecting behind the obstructed orifice of the vagina, gradually collects in anti distends the walls of the uterus, and ultimately mounts up into the Fallopian tubes, distending them also in the same manner as the uterus. But atresia of the vagina or uterus, causing such accumulations, is not necessarily con- genital, but may be consecutive on adhesive inflammation attacking these parts ; as in the instance of a woman, whose case is related in the American “Journal of Medical Sciences,”* and who, after her second confinement, had an attack of metritis, terminating in cohesion of the uterine walls and consequent occlusion * No. XXXV. of the cavity of the uterus. Behind this ob- struction the menstrual fluid accumulated until the Fallopian tubes became so enor- mously distended that at length one of them burst, and death resulted from the escape of the blood into the abdominal cavity. Or lastly, the menstrual fluid may collect in the tube after the manner of the blood in the case just described, where both the ori- fices of the tube are obstructed. Of such accumulations I have met with many ex- amples ; and it is interesting to observe that here, as under many like circumstances, the walls of the tube usually become hypertro phied in proportion to the degree of pressure caused by the accumulations of fluid which they are called upon to resist. These collections of menstrual fluid within the tube, which I have found to be consider- able in some instances, where I have ascer- tained beyond question that death had taken place during a menstrual period, are instruc- tive, as showing, upon strong probable evi- dence, that the menstrual fluid is supplied in part by the walls of the Fallopian tube as well as by those of the uterus itself. For I have seen it in cases where both orifices of the tube were obstructed ; and therefore in cases where it was not probable that the fluid could have regurgitated from the uterus into the tube. ■ Collections of serous fluid. Hydrops tubcB Hydrosalpinx. — In catarrhal inflammation of the mucous lining of the tube, whether oc- FALLOPIAN TUBE OR OVIDUCT — (Abnormal Anatomy). 619 curring in the acute or chronic form, the fluid, secreted more abundantly than in a state of health, may find vent by either or both of the tubal orifices, so long as these re- main pervious. It is probable that in this affection the superabundant fluid flows generally by the lower orifice into the uterus, and so escapes per vaginam, constituting one of the numer- ous forms of “ leucorrhoea.” But if both ex- tremities of the tube are closed, then, as in the case of hemorrhage or menstruation oc- curring under like circumstances, the fluid collects within the tube and mechanically distends its walls. The pressure producing this distension, when operating in only a slight degree, causes a nearly equable enlargement of the tube, so that its natural conical shape is still preserved. But as the quantity of fluid increases, the thin- ner and less resisting portions of the walls, which lie towards the distal extremity, give way more rapidly than those at the proximal end ; and the tube, after becoming irregularly tortuous, is at length converted into a series of sacculi, the largest of which, usually of a pyriform shape, occupies the extremity of the tube (Jig. 122. d). From the irregularity writh which different portions of the tube walls dilate under the Distension of the Fallopian tubes, with obliteration of both orifices. (After Hooper.') a, uterus ; b, vagina ; c, 03 uteri ; d and/. Fallopian tubes ; e, ovary. pressure of the accumulated fluid, it often happens that several angles are formed by the sudden bending of the parietes, and at these points the tube walls, extending inwards, con- stitute so many valvular projections which partition the tube into several irregular cham- bers, communicating together by narrow ori- fices. Such a condition of parts may be frequently observed upon both sides of the body, as in Jig. 422., where both tubes are affected in the same manner although in un- equal degrees. When these dilatations have attained to any considerable size the condition of the lining membrane of the tube becomes altered, so that the mucous gradually acquires the cha- racter of a serous surface, and the fluids collected . within these sacculi present the ordinary condition of the fluids of serous dropsies. The more simple of these fluids are thin, serous, and nearly colourless, and may be more or less albuminous. Not infrequently, however, they contain fiocculi, or are thick- ened by the admixture of various yellow, brown, or chocolate coloured denser fluids, consisting chiefly of pus and disintegrated blood. The quantity of fluid does not commonly exceed a few drachms, and in ordinary ex- perience six or eight ounces w'ould be a rather large accumulation. Yet it is certain that sometimes a much more considerable collec- tion has been observed. Thus in “ Bonnet’s Sepulchretum Anato- micum*,” a case is given in which one of the tubes held thirteen pounds of fluid ; and De Haen-j- mentions an instance in which the hypertrophied tube weighed seven pounds, while the quantity of fluid contained in it amounted to thirty-two pints. Other cases, of more or less authority, have been recorded, in which the collection of fluid has been estimated at 112, 140 and loO lbs. But it is exceedingly doubtful if the tube walls are capable of dilating to the extent that would be necessary to support so large an amount of fluid w'ithout laceration. For it is very well known that in tubal pregnancy rupture of the tube almost always occurs before the middle period of gestation is reached ; and even in those cases where the reports are founded upon post-mortem ex. * Lib. III. Sect. XXL Obs. 39. t Hat. Med. Toni. III. p. 29. C20 UTERUS AND ITS APPENDAGES. amination it is very possil)le that a part of the fluid was contained in tlie ovary, for a concomitant enlargement of both tube and ovary is a very common occurrence, as in the case represented in fig. 422.; and on tliis account no record of any very considerable dropsy of the Fallopian tube shouUl be con- sidered as complete, unless the condition of the corresponding ovary is also mentioned. Collections of piiriform fidd hi the tube. — Abscess of the tube. — The presence of pus in the Fallopian tube is most frequently asso- ciated with suppurative puerperal inflammation of the uterus and its appendages generally. But it may also occur independently of the puerperal state, and as a consequence of ca- tarrhal inflammation of the mucous lining of the tube which may have passed into the sup- purative stage. Tliese cases differ from the foregoing, not only in the nature of the con- tents of the tube, consisting here of pus or of puriforin fluiils with admixture of other in- flammatory products from the lining membrane of the tube; but also in respect of the great tendency which is here observable to the for- mation of adhesions and the establishment of fistulous openings into adjacent parts, as into the bladder, intestines, or peritoneum, into which cavities these fluids are occasionally discharged. Cpsts containing fluid attached to the tube. — Very commonly there may be observed one or more cysts containing a small quantity of transparent fluid, attached by a nairow pe- duncle to the tube, and particularly to the distal extremity ( fig. 368. c). The nature of these cysts has been already explained. (See p. 597.) They can only be regarded as morbid when they attain to an unusual size, as in fig. 421. They are occasionally found as large as a nut, l)ut they very seldom exceed, and indeed do not often attain even to this size. Fibrous tumours. — One of the most re- markable points of difference between the morbid conditions of the Fallopian tube and of the uterus respectively is the very gi'eat rarity of the occurrence in the former of those fibroid growths, which in the latter constitute its most common abnormal peculiarity. No- thing can mark more distinctly the difference of texture between these two parts than this very characteristic circumstance : since it is now known that the peculiar fibrous tumour of the uterus is formed at the expense of the natural tissues of that part. Occasionally, indeed, small fibrous tumours are found in the parenchyma of the tube, but these never attain to any considerable size. These oc- casionally undergo calcification, from a deposit of earthy material in their texture, and thus form little masses of stony hardness which project from the walls of the tube, and are covered by its peritoneal coat. Tubercle is occasionally formed in the Fal- lopian tube. It oceurs there usually in the form of tuberculous infiltration, which, in the opinion of Rokitansky, affects chiefly the mucous membrane of the tube. The occur- rence of tubercle here presents nothing re- markable enough to call for further special description. Cancer of the tube is not a common oc- currence. I have never met with it inde- pendently of cancer of the ovaries or uterus; but when either of the latter organs are exten- sively affected, the tubes are also occasionally involved. Upon the malignant diseases of the Fallopian tube most pathological writers are nearly silent ; nor has our literature been enriched by any considerable number of special records bearing upon this point in Pathology. Rupture of the Fallopian tube. — Spontaneous laceration of the walls of the tube occurs sometimes as a result of over-distension, or too great attenuation of its tissues, whereby the parietes are rendered no longer capable of resisting the increasing pressure of the fluids accumulated vvithin. In this way large col- lections of serous, purulent, or .sanguineous fluids are sometimes |)oured out into the cavity of the abdomen, unless, indeed, by the previous adhesion of the walls of the tube to surrounding parts, the point of rupture is directed to some neighbouring hollow visens by which the fluids escape externally. But rupture of the lubes will most frequently happen in connexion with the tubal form of extra-uterine gestation, which is next to be described. Detention and abnormal Development of the Ovum in the Oviduct. Tubal Gestation. Gra- viditas tiibaria. — This constitutes a second species of those aberrant forms of gestation, commonly termed extra-uterine, one of which has been considered under the title of Ovarian Gestation, (p. 586.) It has been already shown, that one prin- cipal office of the Fallopian tube is the con- I veyance of the ovum from the ovary, or place | of its first formation, to the uterus, or seat of I its final development ; and that the ovum, 1 whilst in transitu, not only becomes impreg- 1 nated, but also exhibits certain indisputable evidences of commencing development, which, however, has usually advanced only a few stages by the time that the ovum enters the uterine cavity. The tube, therefore, as well as being an oviduct, is also the seat of normal impregnation ; whilst, in addition, it serves to protect and possibly, in some slight degree, to add to the material of the ovum, although the actual operation of the tube walls upon the surface of the ovum in this respect must ne- cessarily be very slight in the mammalia, since it so rarely hap|)ens that any increase in it.s size is perceptible from the time of its quitting the ovary to that of its reaching the uterus. But the impregnated ovum, instead of en- tering the uterine cavity, may be accidentally detained in the tube, and undergo further de- velopment there. The extent to which this development may proceed will depend in a ^ great measure upon the capability of expan.don | of the tube walls ; a circumstance which i seems to vary greatlv in different individuals, : and also in some degree according to the 1 portion of tube which the ovum occupies. The differences observable in this latter | 621 FALLOPIAN TUBE OR OVIDUCT — (Abnormal Anatomy). respect have led to a division of cases of tubal gestation into three varieties, viz. tubo-ovarian, tubal, and interstitial. In the first variety, graviditas tubo-ovaria, the ovum becomes developed in a sac, of ■which a principal portion a[)pears to be fur- nished by the hypertrophied walls of the infundibular end of the tube, and the proper tissue of the ovary combined. In the second, graviditas tubaria, the developed ovum occu- pies some part of the canal of the free portion of the oviduct ; while in the third, graviditas interstitialis, the seat of development of the ovum is that part of the tube which traverses the uterine walls. In the first, or tubo-ovarian variety, the parts supplying the principal foundation of the cyst, which surrounds the foetus, are in the first instance probably chiefly normal struc- tures ; and it is easy to understand how, during the progress of growth of the ovum, when the limit of expansibility of these parts has been reached, there may be superadded to them materials for the extension and fur- ther growth of the cyst walls ; and in this way are apparently formed these large sacs, or artificial uteri, which have been sometimes observed to surround a fully developed foetus, and which in the course of their growth have come to include omentum, mesentery, or in- testine, and other portions of the abdominal viscera or parietes, by which the sides of the sac become strengthened and enlarged. As in the case of ovarian gestation for- merly described, so in the varieties termed ovario-tubal, it is only when death has taken place during the early stages of formation of these embryo-bearing cysts that the exact nature and relation of the parts originally composing them can be made out. Hence the difficulty of determining, in more advanced stages of gestation, when other parts have been superadded, in what precise situation the development of the ovum was commenced. And hence the probability that some at least of those cases which have been recorded from time to time as examples of the foetus deve- loped in the cavity of the abdomen, and among the intestines (graviditas abdominalis'), may have been originally cases of the tubo-ovarian variety, in which the cyst walls, commencing their formation by the artificial union of the expanded termination of the oviduct with a portion of the ovarian parietes, have in the course of their growth come to include many other parts. The second variety, which includes all cases strictly termed tubal (graviditas tubaria), con- stitutes by far the most common of all the forms of extra-uterine gestation. Here the ovum is developed within some part of the free portion of the tube, whose walls appear, from the examples which most of our mu- \ seums furnish, to be capable of a very limited • degree of expansion in most individuals. Hence, when the ovum has attained to a cer- ' tain size, and usually by the time that the second or third month of gestation has been \ reached, rupture of the tubal wall occurs. followed by rapid death from haemorrhage. And thus the parts are usually obtained for examination in such a state as to leave no room for question regarding the precise seat which the ovum occupies, and the nature of the parts enclosing it. For in these cases of early rupture the tube has contracted no adhesions with surrounding parts, and the walls of the embryo-bearing sac are formed of the parietes of the oviduct alone. The third variety of tubal gestation, distin- guished by M. Breschet under the title of Graviditas in uteri substantia; and by Profes- sor Mayer, of Bonn, as Graviditas interstitialis, has been made known, particularly by an essay of the former devoted to this subject.* This variety differs from the last mentioned chiefly in the circumstance, that the seat of development of the ovum is that portion of the canal of the tube which passes through the solid walls of the uterus. Here the sac surrounding the foetus is formed in a great measure at the expense of the proper uterine tissues, and consequently the parietes of these cysts exhibit under the microscope a very different composition from that which the tube walls show in the second variety. In interstitial cases the walls of the sac surrounding the ovum sometimes attain in parts a thickness nearly equal to that of the gravid uterus. On section of these portions the appearance which they present is precisely similar to that of the gravid uterus itself. There is here seen precisely the same arrange- ment of large vascular openings, being the divided canals or sinuses which everywhere permeate the solid walls, in whose composi- tion may be traced the same abundance of smooth muscular fibre, as in the ordinary gravid uterus. Within such a sac, formed out of the walls of the tube in the first instance, and in the case of this third variety further strengthened by the addition of a large quantity of tissue derived from the uterus, the ovum lies, pre- senting its ordinary character of an external chorion and inner amnion ; the fcetus or embryo itself, according to the period of ges- tation, being perfectly formed. The walls of the sac, being in this case usually much stronger than when the ovum lies nearer to the distal end of the tube, resist pressure for a longer time, and consequently the foetus may attain a greater growth. One of the most interesting questions con- nected with this subject is, whether a decidua is here formed. Schrceder van der Kolk, in his recent most valuable work on the struc- ture of the Placenta f, answers the inquiry iu the affirmative, in contradiction to the state- ment of Virchow J, by whom it is asserted that in the case of tubal gestation no decidua * Meraoire sur une nouvelle espece de grossesse extra-uterine. Par M. Breschet. I Waarnemingen over het Maaksel van de Men- sehelijke Placenta. Amsterdam, 1851, p. 88. et seq. J Virchow', ueher die Puerperal Krankheiten Verhand. dev Ges. fiir Geburtshelfe. Berlin, 18^8, B. 111. s. 180. 022 UTERUS AND ITS APPENDAGES. is to be found in the tube. According to Schrceder, a decidua is here formed in tubal pregnancy, notwithstanding that in tlie walls of the tube glandidte utriculares are entirely wanting. The villi are here embedded in little hollows of the decidua, upon whose walls the blood vessels terminate in open mouths, and thus the blood is poured out into the jdacenta. The decidua is, indeed, in this case firmer, and does not e.xhibit so many valvular openings as are present in an ordi- nary placenta ; probably from the absence of the utricular glands. In this case, also, an epithelial layer derived from the decidua covers the villi, and serves at the same time as a means of Junction between the parts.* Associated usually with the abnormal deve- lopment of the ovum in the oviduct is the for- mation of a decidua in the uterus, the nature of which structure will be considered in a subse- quent portion of this article (pp. C35. C32). And here it naturally occurs to inquire into the probable causes of the development of the ovum in a situation so unfavourable to its further and complete evolution. Since, not- withstanding the wonderful power of adapta- tion which is in these cases exhibited by the parts immediately surrounding and containing the ovum, it is plain that the oviduct how- ever altered, yet, on account of its peculiar form and texture, can but inadequately supply tbe offices of a uterus. It can serve but im- perfectly for the nutrition and protection of the foetus, and not at all for its expulsion, even should the latter reach the term of its dependent or intra-uterine life. One of the most remarkable circumstances relating to this curious subject, is the fact first noticed, I believe, by Dr. Oldham, that in a large number of cases of tubal gestation, the corpus lutcum, corresponding with the ovum impregnated, is found in the ovary of the op- posite side to that of the tube in which the ovum is developed. Thus if the left Fallo- pian tube contains the ovum, the right ovary will often display the corpus lutenm of a cor- responding date, and vice versa. Not being at first aware of Dr. Oldham’s observation, I had myself noticed the same circumstance in re- peated instances, and had arrived at the same conclusion as he has done in explanation of it, namely, that at the time of the ovum quitting the ovary, the tube of the one side embraced the opposite ovary, and conducted away the ovum, which being impregnated in the ordinary way, and then being delayed at the angle formed by the bending of the tube, has its further progress obstructed at that point until it attains too great a size to ad- mit of its subsequently passing the lower orifice and entering the cavity of the uterus. If it be objected that this explanation is not satisfactory, because it assumes the ap- parent improbability of the fimbriated ex- tremity of one Fallopian tube being able to * Upon this point I do not here give any obser- vations of my own, as I am preparing these for publication in another form. grasp the opposite ovary, then I can point to a preparation in the Cambridge University Anatomical Museum*, in which both the Fallopian tubes grasp the same ovary to which their extremities are affixed by morbid ad- hesion. Another and very different explanation of this remarkable circumstance of the impreg- nated ovum and corresponding corpus luteum being found on opposite sides, has been given by Dr. Tyler Smith -]-, who believes that the ovum, after descending the Fallopian tube of one side, traverses the upper part of the uterine cavity, and ascends the opposite ovi- duct, where it becomes developctl. I might also furnish the advocates of this doctrine with an argument founded upon a most in- teresting and curious observation of Bischoff, which ajjpears to have been overlooked, but which would at first sight seem to support this view. Bischoff, in his essay on the de- velopment of the ovum in the dog and rabbit, frequently noticed a remarkable apportioning of the ova between the two cornua of the uterus, so as to equalise their number on the two sides, when these had been ori- ginally unequal, as shown by the number of corpora lutea found in the ovaries. Thus, in the case of a bitch whose right ovary ex- hibited one, and the left ovary five corpora lutea, each half of the uterus contained threel ova, so that two of the ova must have tra-T veiled across from the right to the left side.'^ But it must be observed, that in tbe cases recorded by Bischoff the ova never ascended, the Fallopian tube, but only travelled fronF one cornu of the uterus to the other. J When, therefore, we take into considera- tion the great difference between the solid uterus of man and the intestine-like organ of the mammalia, on which these observations were made, there appears to be great diffi- culty in supposing that the ovum could alter once arriving at the uterus again enter an oviduct, especially when also it is remembered that while the conical form of the Fallopian tube, whose smallest aperture is towards the uterus, constitutes a provision for ensuring the arrival of the ovum there, this arrange- ment would greatly diminish the possibility of a retrograde movement taking place in tne human subject, if indeed it would not alto- gether prevent it. But to those cases of tubal gestation in which the corpus luteum is found in the cor- responding ovary, neither of these explanations would apply. Here it is only necessary to suppose, that either the developmental changes already tlescribed as occurring normally to t'lc ovum in the tube, have j)roceeded more rapidly than usual, or else, that the ovum, having been accidentally delayed for a longer time than ordinary in transitu, had acquired too great a magnitude to admit of its passage by the ute- rine orifice, even admitting, as some have supposed, that this orifice may, to a certain * No. 722. t Lancet, No. xv. vol. i. 1856. UTERUS — (Normal Anatomy). 623 extent, dilate, for the purpose of allowing the ovum to pass, just as the os uteri dilates at the time of labour. UTERUS. Normal Anatomy. (Syn. Womb, Mother, Eng. ; Mrirpa,‘''Ccrrepa, Ae\ I [rlicoe, having intermediate furrows, often II traversed by lesser plicae, which extend the j secreting surface, and furnish a more consi- derable seat for those numerous mucous crypts which abound upon almost every por- tion of this structure. 1 The forms which the cervical folds or , plicae 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. {J^ig. 431. c c.) Com- P 629 UTERUS — (Norsial Anatomy). mencmg 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 oft’ lateral plicte, 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 plicte, or those next to the raphe, often exhibit the same bulbous extremity; and these together fill the upper or narrowest [lortion 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 fidl 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 anil 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. -1-24.). 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 [losition 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 outwardly 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 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 ])lica;, 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 plicte in the Fallopian tube already described. After repeated pregnancies these plicm 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 arhor 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 pcnniform rugcB is more strictly applicable ; and to those cases in which several parallel folds, iifter ascending ob- liquely, form a series of lateral arches, or suddenly bend over and then ilownwards, the title of plicce palmatce, or as some employ \t, palmcc plicatcB, 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. Enlarqed 9 diameters. (After Tyler Smith, and Hassatl.')* * This figure is from a valu.able Memoir on the Pathology and Treatment of Leucorrhcea, in vol. XXXV. of the Medico-Chinirgical Transactions, 1852 ; 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 UTERUS AND ITS APPENDAGES. (hiO 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 ra])he is sometimes found, uniting a portion of the plicte ; blit 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 Irom it, under whatever form they may appear, constitute together a series of primary foUls, from which others of a secon- dary order are pi'oduced. These emerge from F/g. either side of the lateral plicae, 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 (Jig. 432.). Structure and arrangement of the tissiw.i 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 exam|)le, be separately displayed, because each passes so imperceptibly into the others, that although to the naked eye an apparent distinction may 433. Section of female pelvis and its conhdned viscera. (After Kohlransch,* — reduced.') A, uterus; n, bladder; cc, 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 tlie posterior wall of the cervix and the pieritoneum ; n, vagina. Zur An.itoinic und Physiologie der Bockenorg.ine, von Dr. 0. Kohlrauscli, Leipzig, 1854. 631 UTERUS — (Normal Anatomy). 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 proper 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 surfitce 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 {va'). Beyond this the whole of the remain- ing portion of the anterior wall of the cervix, measuring above one inch in length {bF), is left uncovered either by mucous or serous membrane. At the termination of this space the peritoneum, reflected ott'from the bladder, reaches the uterus, and after investing the organ, is continueil down to and beyond the fornix of the vagina {f). 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 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 Kblliker contractile fibre-cells, in which a single elongated oval nucleus may be occa- s s 4 632 UTERUS AND ITS APPENDAGES. sionally brought into view witli difficulty. They all contain minute dark granules easily distinguished, and they sometimes exhibit u|)ou their surface slight longitudinal folds or markings. These fibres have an average length of and breadth of gjfg-o". They are deeply imbedded in the uterine sid)stance from which they are with difficulty obtained separate, but they may be commonly seen projecting to the extent of about half their length from the torn margin of the |)reparation, and they are easily rendered Fig. 434. Smooth-muscular fibre of uterus, a, fibres united by amorphous matrix ; h, separate fibre and elementary corpuscles. {Ad Nat.) visible in its substance by the aid of dilute acetic acid. These fibres tio not apparently (tossess any distinct cell membrane. In very thin sections the ends of the fibres which have been transversely divitled are seen as if solid, and the cut fibres do not collapse, nor have I ever been able to detect any appear- ance of a flowing out of fluid contents, which would be the case if the individual fibres con- sisted of a cell wall containing fluid (.Jig. 434. «). 2. Round and oval nuclei, or elenienlary corjmscles. — These measure ia diame- ter. They are found in many parts inter- mixed with the fusiform fibres, but they are most abundant towards the inner layers of the muscular coat. They are ajiparently the elementary or embryonic condition of the fusiform fibre-cells Just described. For al- though the two extreme forms of round cor- puscles and fusiform fibres are the conditions under which these constituents of the mus- cular coat are most numerously seen, there may yet be traced a sufficient number of apparently intermediate stages to justify the conclusion that the one is but the embryo form of the other ; the round corjiuscles becoming at first oval, and then being length- ened out into the fusiform state (Jig. 434. h). 3. Amorphous or homogeneous connective tis- sue.— A considerable portion of connective tissue exists in certain ])arts 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, ajjpear to have scarcely any other connecting medium but this, especially in young subjects, while in the middle and outer- most laminae a large |)ortion of fibrillated tissue is adiled, and the amor|)hous 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 bunilles of muscular fibre, as shown wjig. 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. i Among them, however, ,and especially at the points where the laminae are separated, are seen numerous thin flat 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‘d curling lines, such as viould indicate the inter-* mixture of a small quantity of elastic tissue. 3. Elastic fibrous tissue. — The elastic form ;; . of fibrous tissue is also [iresent 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 develo|)ed single fibres matted together, of the finer kind, commonl\ known as nucleus fibres; and also more abundantly the peculiar fusi-',. form formative cells from which these arise. ,, 1 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 ! which 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 i channels, that the mottled appearance of tfic 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 633 UTERUS — (Normal 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. Mine. 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 after giving an account of what is seen upon the surface of the organ when the peri- toneum has been stripped off after prolonged maceration. INIore 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 lamina; 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 particulai ly 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 embr3- onic condition. Here the fibre-cells form bundles, situated between the ramified canals or utricular 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-cells 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 innermost 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. 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 iVat) caused by the intermixture of numerous mi- nute white lines ramitying within a darker substance, and dividing it into a multitude of small lozenge-shaped spaces. The vvhiter lines mark the course of the finer uterine vessels, together with the bundles of white fibrous tissue which accompany them. The browner lozenge-sha]ied 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 fig. 428., 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- nte, 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 laminm, 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 usuallv 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 liy acetic acid ; hut 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 Nut. 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 iu 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 \n fig. 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 com[)onent 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 considerabij 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 middie strata may be distinguished as the vascular laminae of the muscular coat. External to these again lie a series of thin sheet-like laminae (Jig. 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 C35 UTERUS — (Normal Anatomy). being inseparable from the peritoneum by which they are covered. These fiat, 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 anterior and [)osterior uterine walls ; meeting at length in a central perpendicular raphe, in which a few longitudinal bundles may be generally seen. These tegumental laminse are composed almost entirely of fusiform fibres, with very few embryonic corpuscles. They are united 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 amorithous 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 con,stituents 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 eoat ; Idniiig 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 {Jig. 438.). These ap[)arent 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', vvhile 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 toinentose or ap|)arently villous comlition of the surl'ace occasioned hy the loosening out and partial detach- ment of the capillaries which freely ramify within this meinl)rane is observed, The lining membrane of tlie uterus differs from mucous membranes in general in hav- irig no sub-mucous tissue, so 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 [treparatious are examined by transmitted light with a common lens, or witli 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 [termeate its substance, running chiefly in a direction iterpemlicular 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 disa])[)ear, 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 em|iloyed, 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 grailations, the ditlerence between them being then shown to be morphological rather than structural, at least, at the [joints of their confluence. The mucous membrane lining the uterine cavity is composed of the following elements, besides the utricular glamls, capillary vessels, and epithelium, viz., — free elementary cor- jmscles or nuclei, contractile fibre-cells, and amorphous connective tissue. 1. Free elcmentury corpuscles or nuclei. — These are in all res|)ecfs [irecisely similar to the elementary corpuscles already described as constituting apparentl}' the embryonic state of the contractile fibre- cells in the muscular coat. They form in conjunction with the amorphous matter 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 ver^' 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 largelj' into the composition of the utricular glands. It presents no special cha- racter retjuiring 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. II. Weber and Professor Sharpey, constitute the most remarkable cha- racteristic of the uterine mucous membrane. I3y 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 t 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- j stance of the parenchyma of the mucous ,| membrane towards its free surface, where they ' terminate each in a separate orifice. In Ruminautia and Pachydermata they are i large, and take a serpentine direction, so that j they may be easily mistaken for vessels. By i Burckhardt -j-, indeed, who has described them j in the cow, they were termed vasa spiralia. j Their spiral course is more obvious in the j 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 the.se require the aid of a lens for their detection. In the dog, two sorts of glands are de- scribed by Professor Sharpey j;, simple and I compounti. 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 Eobin and Keicliert ; vide Robin, “ liUmoire pour servir it I’Histoire Anat. et Path, de la Memb. Muqueuse j Ute'riiie; Arcliiv. Gen. de MAI. iv. sA'ie, torn. ||| xvii. ; Reicbert, Ueber die Bildung der hinfitlligeu j Hiiute; Muller’s Arebiv fur Anat. Phys. 1848. t t Observ. anat. de Uteri Vaceini Fabrica. j j Muller’s Physiology, by' Baly', 1837, p. 1574. ^ 637 UTERUS — (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 ramilying 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 chiefiy 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 Fis. 438. Section of the entire thickness of the uterine mucous membrane (decidua) in the unimpregnated state, with a smalt 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 JVat.) 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 re[)resents them, or * It appears to me that the well-known repre" sentations of the human uterine glands by E. H- IVeber (Zusatze zur Lehre voin 13aue und den Ver- richt tier Geschlechtsorgane, Taf. viii. f. d, 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. whether by any indirect communication with the uterine vessels, which many considerations both physiological and pathological seem to point out as at least [)ossible. The difficulties attending this part of the enquiry have been ably illustrated by Dr. Sharpe}’, and my own investigations fully confirm his statements upon this point. Nevertheless I have in many in- stances succeeded in distinctly 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 2^'' to sio '- In addition to the glands or canals already described, there may be often observed inter- mixed with them short mucous crypts, or even closed follicles. These appear to have been little noticed in the uterine cavity, but they are very distinctly seen when accidentally dis- tended by accumulation of fluid. They then constitute a variety of those growths, which in more advanced stages have been designated by Dr. Oldham channel polypi. The arrangement of the capillary vessels of the uterine mucous membrane is peculiar and Fig. 439. Net- work of capillaries on the surface of the mucous membrane of the uterus. a, from the body; b, from the canal leading to the Fallopian tube. In the centre of each of the meshes is the orifice of a uterine gland. (Ad Nat.) characteristic. The capillaries, which are of large size, usually descend between the canals of the uterine glands, giving to them a few * Upon this subject see further, p. 666. 638 UTERUS AND ITS APPENDAGES. small branches in their course. Having reached the surface of tlie mucous membrane they spread out into a meshwork of round oval and hexagonal spaces, in the centre of each of which may be usually observed the orifice of a uterine gland. This is most easily seen in the neighbourhood of the Fallopian tubes, where the capillary network and glandular orifices are usually arranged with greater regularity than in other portions of the uterine cavity. In many places, however, the small vessels furnishing the ca|)illaries of the mucous mem- brane may be seen in injected preparations, lying close beneath the surface with which they run parallel, and if the veins have been filled, one or two principal ones may be no- ticed on each half of the median line, running in the longitudinal direction, ami communica- ting by short branches with the cajtillarics just mentionetl, from which the blood is thus conveyed away through the muscular walls to the larger veins. The network of capillaries thus formed lies very superficially with regard to the uterine surface. The layer of epithelium covering them, and the nuclear corpuscles and amor- phous tissue supporting them, appear to have so little cohesion, and to form so slight a pro- tection, that the vessels are often seen to be nearly bare, while in some instances the indi- vidual capillaries may be observed hanging out loose into the uterine cavity, and giving to its surface a villous appearance. This constitutes one of those conditions which have led many anatomists to assert, and more to deny, that the mucous membrane of the cavity of the uterus is furnished with true villi. Structure and arrangement of the tissues composing the cervix. — The cervix is com- posed of nearly the same elements as those which form the body of the uterus, but they are difl'erently proportioned and arranged in the two organs. The cervix cannot be said to consist, like the body, of three coats. It receives a cover- ing of peritoneum only upon its posterior surface, while the anterior wall, as well as the lateral borders, remain uninvested. With the exception, therefore, of this partial cover- ing, the cervix consists of a muscular and a mucous coat only {Jig. 426 — 431.). Muscular coat of the cervix. — On account of the large admixture of fibrous tissue with the muscular element here existing, this might with almost as much propriety be called the fibrous coat of the cervix. The muscular element of the cervix consists of the same fusiform fibre-cells as in the body ; but the elementary corpuscles are here scan- tily seen. The fibrous element consists of long detached fibrils or of bundles of fibres of white fibrous tissue intermixed with much unformed material of the same kind, but stronger and tougher than that which unites the constituents of the muscular and mucous coats of the uterine body. These several tissues are arranged in a manner not materially different from the plan already described as observable in the body of the uterus. But the thin external strata which form the tegumental layers of the body are wanting in the cervix. There may, how- ever, be distinguished an outer and more vascular, and an inner and more dense series of lamina;. The laminae of the outer series are intermingled with numerous divisions of the cervical branches of the uterine vessels which traverse them obliquely in a direction from above downwards and from without in- wards. From the abundance of these vessels the external laminaa present a more s[iongy appearance, and when the part has been in- jected a much deeper colour than the inner layers, which are paler, more dense and closely set, and exhibit at the same time fewer sections of vessels, and these only of the finer kind. The large amount of white fibrous tissue, and the density and compact- ness of the lamince here formed around the cervical canal, give to clean sections of this part an appearance of circles concentrically arranged. But a low magnifying power is sufficient to resolve these into the lozenge- shaped spaces already described, consisting of bundles of contractile fibre cells bordered by fibrous tissue, and intermingled with bun- dles of the latter and blood-vessels of various sizes. Within these laminae and bundles the fibres take their course with as many varia- tions in direction and plan of arrangement as are noticeable in the muscular fibres of the rest of the uterus. (See Jig. 436.) The larger proportion of the fibrous ele- ment in the neck as compared with the body of the uterus, which the microscope serves to display, and which to a certain extent is ob- servable to the naked eye, may be more satis- factorily shown by the operation of dilute acetic acid ; this agent causing thin sections of the part rapidly to swell out and assume a gelatinous appearance. Mucous coat of the cervix. — This is com- posed of epithelium, basement membrane, and the usual fibrous and vascular tissues, together with certain papillse and follicles. It is of a more dense and uniform texture upon the outer or vaginal portion of the cervix than within the canal, where it is more delicate, but being here thrown into nume- rous folds and rugae, an appearance is given of greater thickness than the membrane really [iossesses. The average thickness of the mucous membrane upon the lips of the cervix is i — that of the membrane with- in the cervical canal, regardless of the folds, is somewhat less. The general plan of ar- rangement, and some of the more prominent forms which this membrane assumes within the cervical canal having been already con- sidered, it only remains here to describe the minuter structures of which it consists. The epithelium of the outer or vaginal por- tion of the ceiVix is tessellated or squamoits. It gives a smooth and even covering to the two lips of which this part of the cervix con- sists. Outwardly, this scaly epithelium is continuous with that of the vagina, but to- wards the os uteri it terminates at the margin 639 UTERUS — (Normal Anatomy). of either lip. Within the cervical canal the epithelium changes its form. It has been described here as constantly cylindrical or dentate; but upon all the finer structures here found, such as the filiform papillae, this so-called epithelial covering consists, as Reichert has well described, and Kilian ac- curately represented it, of elementary cells, whose cell membranes are closely united to- gether, having a polyhedral outline, and with- out undergoing such an amount of flattening as to lose their spherical form. They contain a slightly flattened nucleus with several nu- cleoli, surrounded by a clear somewhat thick fluid intermi.xed with molecular bodies, and sometimes oil globules. Some difference of opinion exists as to the part of the cervical canal in which the epithe- lium first becomes ciliated. Drs. Tyler Smith, and HassalJ, who have examined numerous uteri at an early period after death, with a view to anticipate post-mortem changes, state that the ciliation of the epithelium commences in the rugose portion of the canal, and ex- tends ii|) to the fundus, while the epithelium just within the os, though also cylindrical, is not ciliated.* It should be observed, however, that there is no particular portion of the cer- vical canal in which the membrane constantly becomes rugose, but that the rugosities often extend quite down to the margin of the os. According to Henlef, the cervix is provided with ciliated epithelium from the middle up- wards, and w'ith pavement epithelium from that point downwards. One peculiarity or variety in the arrange- ment of the epithelium upon the vaginal por- tion of the cervix requires special notice here on account of the singular degree of import- ance which has of late years been attached to it, and still more from the remarkable pa- thological speculations to which it has given rise. It occasionally happens that the tessellated epithelium of this part, instead of extending as far as the os, abruptly ceases at a distance of one or two lines from the inner margin of either or both lips, leaving a single or double crescentic patch where the ordinary pave- ment epithelium is replaced by a crop of close- set filiform papillae, projecting very slightly, if at all, above the general surface, and pre- senting to the touch that velvety feel, and to the eye, on account of their great vascularity, that florid aspect, which has often led to the supposition that this mere morphological va- riety of structure is the result of a pathologi- cal change, and that it constitutes a form of ulcer peculiar to the os uteri. Beneath the epithelium is a basement mem- brane, which, upon the outer portion of the cervix, extends in a smooth lamina over the papillm that everywhere crowd this part, but * Memoir on the Pathology and Treatment of Leucorrhcsa, based upon the mici'oscopical anatomy of the os and cervix uteri Med. Chir. Trans., vol. XXXV. 1852. t Allegem. Anatom., p. 246. within the cervical canal it dips into the furrows and follicles, or covers its numerous rugosities and projections. An unequal layer of fibrous tissue, traversed by vessels, and supporting and containing the numerous papillse and mucous crypts of vari- ous forms and sizes which characterise the cervical mucous membrane, completes this structure. Tough and coriaceous upon the outer portion, and thinner and more delicate within the canal of the cervix, it forms the chief substance of the mucous membrane, ami lies immediately upon the muscular coat, the fibres of which become intermingled with it. The pa-pillcB, or villi, as they are sometimes termed, of the cervix, exhibit considerable varieties of size and figure, being conical, verrucose, or tuberculated, dentate, clavate, and filiform. The clavate papillae are usually found fringing the surface and margins of the thinner plicm. The dentate usually form a border to those which are a little more fleshyq and are commonly seen at the margins of the lateral and upper mucous folds. The verru- cose papillte are seen in various situations, but are most constantly observed in the sharp lateral furrows which constitute the lines of demarcation between the two cervical walls. The filiform papillte are the finest of all. They are more slender and pointed than the clavate. They occur under two forms, and in two situations. One of these forms is invariably present on the outer or vaginal part of the cervix. The whole of this portion, from the margins of the os outwardly, is covered by numerous short close-set thread-like papillae, invisible to the naked eye, but with the help of a sufficient amplif\ing power easily distinguished by their white colour, through the somewhat dense layer of pavement epithelium and basement membrane that closely covers and binds them down. Similar papillte clothe the inner sur- face of the vagina, and form, with those just described, a continuous layer. The filiform papillae constituting the second variety are larger and longer than these, so that they may be discerned by the naked eye. They occur usually at the margins of the os, and may be traced to a variable distance within the canal. But their presence here is uncertain, while that of the former variety is constant in the situations indicated. These larger fili- form papillae may be sometimes seen to form the terminations of the longitudinal cervical plicte in those cases where parallel folds run down to the very margins of the os uteri. Here the folds, each ending in a little tuft or tassel, form by their junction a close-set crop of villi, which may merely border one or both lips with a narrow' fringe, or form a velvetty [)atch extending outwardly upon the lips of the cervix, and being here uncovered by the ordinary dense epithelial layer of this region, which, as just stated, sometimes, terminates at this spot with an abrupt margin, they may present the appearance already described as simulating an ulcer. Regarding the minute structure and compost- 640 UTERUS AND ITS APPENDAGES. tlon of the papillae, all but the finer kinds may be vievved as consisting of the same elements as the mucous meuibrane itself, for they ap()ear to be produced by mere notchings or indenta- tions, extending more or less deeply into that meuibrane ; they are, in fact, little more than repetitions of the plicae and sulci upon a smaller scale, with a slight difference ot form. They serve to extend the secreting surface, and possibly to ex[iose a larger aggregate superficies of vascular and nervous tissues. One or more long and slender blood-vessels may usually be traced from the muscular coat running into each |)apilla. These are suf- ficiently conspicuous in thin sections without the aid of injections. By the aid of the latter they may be seen to terminate in vascular loops upon the ends of the papillae, just as similar vessels maybe observed to form wavy coils upon the crests of the [ilicae by which the cervix is linetl. The filiform papillae, both larger and smaller, are more finely-constructed than the rest. They often end in a slightly bulbous extremity. Those upon the outer portion of the cervix are usually single, their length being from two to six limes that of their breadth. The free uncovered filiform papillae of the cer- vical canal and margins of the os are relatively much longer. These latter are commonly branched, and in conformation occasionally resemble the early villi of the chorion. Each villus, whether single or ramified, contains usually a single capillary loop, which returns upon itself, and at the base passes on to an- other villus. Covering the capillary loop is a delicate basement membrane, uniting toge- ther the clear granule-holding nucleated cells, which constitute the e|)ithelial covering as well as the substance of the villi, and of which a description has been already given. No nerves have been traced into the papillae, though Kihan* is of opinion that they are spe- cially tactile or sensitive structures, and from various circumstances to be hereafter con- sidered, it will appear probable that they are connected with the special nervous attributes of the cervix. I am disposed, however, to regard the sensibilities of the cervix, such as they are, as resident chiefly in the filiform papillae. The mucous crypts or follicles of the cer- vix are, for the most part, simple depressions in the mucous membrane, although in cer- tain situations they penetrate more deeply, and approach in form the ramified and tortu- ous canals of the uterine body. Scarcely any portion of the cervical canal is free from these follicles, which serve to increase the extent of mucous surface, and apparently to furnish the special secretions of this part. They not only fill all the interspaces between the pri- mary and secondary folds, but they are dotted over the ridges and prominences of the cervi- • See a valuable paper by Franz BI. Ivilian, en- titled, Die Structur des Uterus bei Thieren, in Henle and Pfeufer’s Zeitschrift, IX. Bd. cal lining membrane in countless numbers, extending from the interna! to near the ex- ternal os uteri. They commonly cease at a short distance from the margins of the latter, where a smooth space is often observable in one or both cervical walls. But they may be sometimes |>erceived at the very border of the lower orifice, and when in such a case one or both lips are slightly everted, as for example in certain hypertrophies of the cervical lining membrane, this follicular portion becomes protruded, while its florid colour, limited by an abrupt margin of the unaltered and paler scpiamous epithelium here suddenly commencing, an appearance is produced which may also easily be confounded with an ulcer. The mucous crypts seldom extend beyond the border of the os, except in the cases just quoted, when, in fact, the relative situation only of the parts is changed. A few, how- ever, may be sometimes seen scattered at tole- rably regular intervals over the vaginal por- tion of the cervix. They sometimes also occur here, as well as within the cervix, and even in the uterine cavity, in the form of clo.sed vesicles containing an opaline fluid, and per- haps may be regarded as in some instances pathological new formations. The cervical mucous crypts are lined by epithelium and basement membrane. They contain a small quantity of mucus, together with granule cells. Those upon and near the margins of the os uteri may be sometimes observed to contain short papilla within their margin. Blood Vessels of the Uterus. The Arteries are derived from two sources, viz. from the internal iliac and the ovarian or spermatics. The vessels supplied from the former source are termed the uterine arteries. These are two in number, one for each side. They arise from the anterior division of the internal iliacs, and proceeding downwards and in- wards pass between the folds of the broad ligament to the neck of the uterus. Here they take an upward course along the lateral border of the organ, describing several flexuo- sities, and giving off, in succession, branches to the upper part of the vagina, the neck, body, and fundus of the uterus ; the latter inoscu- lating with the branches derived from the spermatics. Free inosculations also take place in the substance and upon the surface of the uterus between the branches of the two sides, so that the entire uterus may be injected from either set of vessels. The branches tlerived from the spermatic or ovarian arteries also enter between the folds of the hroad ligament, and inosculate with the superior divisions of the uterine vessels near the fundus of the organ. When, after a successful injection, thin slices are cut from the substance of the uterus and dried, and afterwards placed in Canada balsam, the whole appears to be a mass ol ve.ssels ; the arrangement of which, however, may be easily UTERUS — (Normal Anatomv.) G-H observed by a liand lens or a low power of the microscope. Many of the arteries down to jjy"'' or in diameter are still seen to take a remarkable corkscrew coarse, with numer- ous very close spirals, especially in the outer half of the sections. Beyond these the ves- sels take a straighter course, and at length, in their finer divisions, run in parallel lines, sending off minute twigs at right angles, which cross the ultimate fibres of the tissue, in the manner peculiar to muscular structure. When the finer vessels of the body of the uterus have reached the mucous membrane, they dip down between the walls of the canals, termed uterine glands, and spread out in a network of ca|)illaries ; the meshes of which surround the orifices of those canals in the manner delineated in fis. 439. a and h. ; and from these the blood is again collected by the small superficial veins, the course of which is described at p. 637. The arteries which supply the cervix pene- trate that part in a direction downwards and inwards, pursuing the same corkscrew course until they have nearly reached the mucous surface, where they break up into finer ves- sels and capillaries, which ramify over the rugae in lines more parallel than those of the uterine body. Both the arteries and capillaries of the cervix are far less numerous than those of the body of the uterus ; and, indeed, the cervix generally in respect of its composition exhibits a lower degree of organisation thaa that of the princijial portion of the organ, although it appears to receive the largest sup- ply of nerves. The veins of the uterus take a course cor- responding with that of the arteries, and are distinguished by the same names. They are considerably longer and more numerous than the latter. They form along the sides of the uterus and within the folds of the broad liga- ment a very considerable pkxus (the uterine plexus), which, together with the venous chan- nels or sinuses ramifying in the uterine sub- stance, are more conveniently examined in the gravid organ, where they undei'go great en- largement. See figs. 444. 449. and 453., and the descriptions of these. Lymphatics. — These vessels are far more easily examined in the gravid than in the un- impregnated uterus. They are very numerous, and are divided by Cruveilhier into ’two orders; the superficial, which lie immediately beneath the peritoneum ; and the deep-seated, which ramify in several places in the sub- stance of the uterine walls. The lymphatics of the cervix terminate in the pelvic and sacral glands. Those of the body of the uterus, after traversing the broad ligaments and uniting with the lymphatics proceeding from the Fallopian tubes, ovaries, and round liga- ments, empty themselves in the glands situated in front ot the aorta and vena cava. Nerves. — The nerves which sup[dy the uterus are derived partly from the spinal, but principally from the sympathetic system. Ac- cording to the dissections of Dr. Snow Beck *, * Phil. Trans., 1840, part ii. p. 2U>. Siipp. the nerves which compose the hypogastric plexus, consisting of gelatinous and tubular fibres derived from the lower part of the superior aortic plexus *, on approaching the neck of the uterus begin to sepai ate, and on a level with the os uteri ate joined by branches which accompany the superior haemorrhoidal artery. The anterior portion of the hypo- gastric plexus, after receiving branches which accompany the iliac arteries, passes inwards by tbe broad ligament, and supplies the lower lialf of the uterus. These nerves, vthich are continuations of the hypogastric plexus, as they approach the body of the uterus se- parate, and each pursues a different distribu- tion. They lose the plexifonn character and form a number of distinct fine cords. These nerves, like all the nerves supplied to the uterus, are chiefly composed of gelatinous fibres, although some tubular fibres accom- pany' them ; but they are few in number, and appear to be far from forming the essential element of the uterine nerves. The middle [lortion of the uterus is sup- plied by a distinct branch from the inferior aortic plexus ; which, without communicating w'ith the hypogastric branches, passes to the upper part of the uterine body and then divides, to supply the part between the previously described branches and the Fallopian tube, sending also a braneb to the ovary. The fundus is supplied sometimes by a * According to Dr. Snow Beck, the white tubular fibres wliicli enter, pass through, and emerge from the semilunar ganglia, are all derived from cerebro- spinal nerves through the medium of the splanchnic nerve, while none of the tubular fibres actually' arise from the ganglia (as Bidder and Volkmann sup- pose). The same was found to obtain in every instance of sympathetic ganglia examined; the tubular fibres could alway's be traced to the white connecting cord between the spinal and sympathetic nerves, and thence to the branch of the spinal nerve from which it is derived. The gelatinous fibres, on the other hand, all take their origin in the corjmscles of the ganglia. In the white cords connecting the spinal and sym pathetic nerves, commonly regarded as roots of the sympathetic, the tubular fibres com- posing these, on being traced back to the spinal cord, were found to be derived from the motor and sensitive roots, in apparently equal proportions. The elements of-t|ie lower part of the superior aortic ple.rus resemble those which form the semilunar gatiglia, v'iz. tubular fibres derived from the lumbar nerves, and gelatinous fibres from the sympathetic ganglia. The inferior aortic plexus is a continuation of the branches from the plexus last described. These divide to form the two lateral hypogastric plexuses, and here a crossing of fibres of the opposite side takes place. The lateral hypogastric plexus is composed of gela- tinous and tubular fibres derived from the superior aortic plexus. The distribution of nerves to the uterus from this, their main source, is described in the te.xt. The sacral nerves, although they supply the vagina, clitoris, labia, sphincter and levator ani, bladder, and rectum, send no direct branches to the uterus ; nor is there, according to this author, any anatomical evidence to support the supposition which some have entertained, that filaments derived from these nerves might by a circuitous route reach the uterus after their union with the pelvic plexus. ITiil. Trails., 18-1(3, part ii. T T 642 UTERUS AND ITS APPENDAGES. branch which proceeds from the renal plexus in company with the spermatic artery, and is distributed also to the ovary. Another set, distinct from these nerves, comes also from the same continuation of the hypogastric plexus, hut forms a plexiform ar- rangement around the vessels ; and among these are found here and tliere minute ganglia. These nerves are very minute.* body of the uterus is formed in man ; while in those animals in which no middle portion or body exists, the cornua remain ununited. As the development of the uterus proceeds, the two cornua become gradually shorter, until at length they are lost, or, as it were, absorbed into the body or fundus of the uterus, which is thus at the same time developed. The accompanying figure, representing the The Develop.uent of the Uterus, and THE Metamorphoses which it undergoes AT Dieferent Periods of Life. a. The origin of the tderus, and its condition during foetal life. — In the human embryo, ac- cortling to the observations of Miiller, during the transformation of the Wolffian bodies, the efferent tube of the generative apparatus un- dergoes the following modifications. In the male, all that portion of the efferent tube which passes along the outer border of the corpus Wolffiannm is thrown into strongly marked convolutions, and this part contributes to the forjnation of the epididymis, while be- low this point the convolutions cease ; and here a hand or ligament, the gubernaculum testis of Hunter, which had been developed at a still earlier period, passes off to the inguinal canal. In the female, the following trans- formation occurs. The tube here remains free from convolutions, but a ligament, re- sembling that of the male, which is afterwards converted into the ligamentum uteri teres, passes off from the same point, to be extended to the inguinal ring. The part of the tube which lies below this point becomes the cornu uteri, and it is by the coalescence of the two cornua at their loiver exti'emities that the Fig. 440. The entire internal generative organs, from a foetus of three months. (After J. Mufter x 8.) a, uterus; ft, round ligaments ; e. Fallopian tubes; d, ovaries; e, remains of Wolffian bodies. condition of the foetal uterus at about the end of the third month of gestation, serves to illustrate these particulars. The ovaries pos- sess the elongated form characteristic of the early condition of these organs. Parallel with them run the Fallopian tubes, and between these are the remains of the Wolffian bodies. At the point where the round ligaments are given off, the cornua uteri begin, and by their junction, which is here not yet complete, so that a slight indentation is left, the uterus is formed. From this period of embryonic life, the |i uterus keeps pace in its growth with the other Fig. 441. Uterus and appendages of human fcetus at term. (After Richard.) a, pavilion of the left side ; a, the same of the right side (below it, in this specimen, is the remark- able variety of two separate accessory’ pavilions ft and c) ; d, Fallopian tube, exhibiting numerous sinuosities in its outer half; f, round ligament; e, ovary. viscera ; and at the time of birth it forms an organ of considerable size, lying high up in * Upon the subject of the origin and distribution of the uterine nerves, consult also Fr. Tiedemaim ; Tabulse nervorum uteri, Heidelberg, 1822 ; and the works of Ur. Kobert Lee, quoted at page G51., where the condition of these nerves in the gravid uterus, and the question of their enlargement during preg- nancy, is considered. And for the minute anatomy of the sy’mpathetic filaments and ganglia, see the Art. “ Sympathetic Nerve.” the pelvis, and occupying a conspicuous place midway between the bladder and rectum. The form, however, of the generative apparatus, at this stage of life, is very different from that i which characterises it at a later period. The I' vagina, cervix, and body of the uterus consti- jj tute one nearly straight stem or canal, horn which diverge, at right angles, the Fallopian j tubes and ovaries with their ligaments, much II in the form of the letter T. Of the two divi- sions of the uterus, viz. the body and cervix, UTERUS — (Development). C+3 the latter is the more considerable, for the bodv has not yet acquired breadth ; while the cervix, forming a tube of nearly equal calibre with the body, possesses almost twice its length. This greater length of the cervix, as compared with the body of the uterus, is one of the most striking characteristics of foetal life (^g.441.), one also which continues to be observed for many years after birth. b. The uterus from the time of birth to pu- berty.— From the time of birth until the approach of puberty, the internal generative organs undergo but little change. Gradually, but slowly, increasing in size, they still retain the princi[)al characteristics of the foetal pe- riod. The uterus consists still chiefly of cer- vix, the body being that part which is last developed. Thus in a child of three years (fig. 442.)< vvhom the entire length of the uterus is 13'", the cervix measures 1 1'", and Fig. 442. Uterus and appendages of an in fant. a, cavity of the body laid open ; h, of the cervix ; c, anterior lip of the cervix ; d, left ovary opened ; e. Fallopian tube ; /, right ovary ; g, internal os uteri, marking the division between the body and cervix. (Ad Nat.') the body only 4"'. These dimensions do not materially differ from tho.se of the uterus in the fir.st year of life, nor do they nmcli exceed those of the same organ at birth. But as puberty approaches, the relative proportions of the cervix anti 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 (^g. 442.), but now gradually acquires the shape already described as characteristic of the cavity of the adult uterus (fig. 431.). The folds or plicae also (fg. 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. 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 distinctl}' seen in tlie 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 up|>er 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. The.se are all imbedded in a semitransparent foritdess matrix, and dif- fer in no respect from the corresponding tissues in the adult, except that they are ge- T T 2 61-4 UTERUS AND ITS APPENDAGES. nerally softer and less tenacious in proportion as they are younger. c. 'Vhe uferws during menslnial life. — Tlie average duration of menstrual life is thirty years. It occupies usually the interval be- tween the ages of fifteen and forty-five. Tlie uterus in liealthy women, throu'.;hont 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 sympatliy, that every periodic change in the condition of the latter is, so far as the present state of our knowledge justifies the assertion, representeil by a corresponding preparatory change in the former. But tlie meusti’ual 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 catamenial 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 ami discharged ; the process of expulsion being accompanied by much suffering ami a greater escape of blood than occurs in ordi- nary menstruation. These dysmenorrhoeal membranes (fg. 443.) present all the cluu’ac- Uig. 443. Pnrliun of the lining membrane of the uterus cast off during painful menstruation, fAd Nat.f teristics of a true decidual structure, having upon their inner side, or that which liad 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 Hocculent appear- * For this illustration I am indebted to Dr. Oldham. ance characteristic of the outer surface of niemhraues 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 tlie description already given of the adult organ ; and these characteristics, if no pregnancy intervenes, it preserves until the perioil arrives at which menstruation, to- gether with the capacity for procreation, finally ceases. d. The ttlcrus during gc.stnlion. The fidhj 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 deve!o|)nient 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 front birth to puberty. The establish- meiat of the latter condition is characterised by a corrcsjtondingly rapid evolution of both these organs. But the pubertal age may not arrive ; the individual may retain, in respect of re[)roductive ca[)acity, 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 perLotl of natural decline in the organ commences, and this is the coi - 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 stinuihis of im()regnation, and partly by the growth o( the ovum, and abnormally by the formation ol * Compare /?jf. 465., repre.senting tlie pre-pubertal uterus in a woman aged nineteen, with fig. 442., of the uterus of a child at three }'ears. 6-1-5 U'l'ERUS — (Development). anv substance within the uterus, such as a polypus, which may cause distension of its wails ; or by the accumulation of fluid in its cavity, such as the menstrual fluirl collected in cases of atresia or imperforation 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 tlie fourth month of ordinary pregnancy. In cases where gestation follows an ordi- nary course, the development of the uterus is such, that the w-eight, at the end of the period, is found to be increased about twmnty-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 he considered. There is no example in man, and fevv 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 formation of the placenta, may he 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 w hich the organ exhibits at different periods of normal gestation. These may be expressed in calendar months as follows ; — RATE OF INCREASE IN SIZE OF THE GRAVID UTERUS ACCORDING TO MONTHS. Length. Breadth. End of 3 months 44 — 5 inches 4 inches. .. 4 „ 54—6 „ 5 „ 5 „ 6—7 „ 54 „ .. c „ »— 9 „ 64 „ „ 7 „ 10 „ 74 „ .. 8 „ 11 8 ., 9 „ 12 „ 9 The autero-posterior has usually an average ol one inch less than the lateral diameter. Weight. — The weight of the gravid uterus, when fully developed, is most correctly ascei- tained in cases where death has taken place during, or soon after, labour at term. In twelve examples, estimated by Meckel, the minimum weight was 2 lbs., and the weight, relatively to the imimpregnated organ, was as 24 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 autero-posterior diameter, pro- ducing the form of a flattened S[)here. 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 corre.-^ponding with these, take place in the cavity of the uterine body. Tbe walls of this flattened triangular chamber begin to sefiarate 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; wdiile 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 w’ords, 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 be bau 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, aiul that towards the end of pregnancy they become gradually much * The estimates of Heschl, given at page 668., differ somewhat from these. t W. Hunter. An anatomical description of the human gravid uterus, page 5. T T 3 04f) UTERUS AND ITS APPENDAGES. thiiinei'. lie found the thickness of the ute- rine walls, three weeks after conce|)tion, C"' Fig. 4-i-l. Jlumttn (jraoid uterus at eiijht months. 7'he vessels have heeii injected, and the peritoneum removed from the sides and fore- pari of the uterus. {After IFm. Hunter.') ((, conimencement of the cervix; hh, portion of the body corresponding with the brim of the pelvis ; ft', habopimi tube concealing the ovary; dd, round ligament; e, hypogastric artery, and /j vein; g, spermatic artery, and h, vein. at the conmicncement of the third month, F" ; :it the coininencement of the fourth month. At tlie end of the fourth month, in two cases, 4"' ; in a third, 3'" at the upper, and 4'" at the lower part ; in a fourth, 5"'. At live montlis, in one case, 3"'; in another, 2"' superiorly, and infcriorly. At six and seven mouths, rather less than 3'" ; at eight months, in one case, 2'", and 2}f"\ 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 tliffcreut 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 W" . * This circumstance is remarkably exemplified in prep. No. 36(1.5, in the Museum of the Royal College ol 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 wdiole 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 palmae plicatse become un- folded, and project in the form of frill-like expansions (./%. 440.) ; 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 repre.sented as seen from the vagina, va, vaginal walls divided ; h, walls of uterus. Half the natural size. {Ad Nat.) collecting here in the form of a plug, as.sists J in shutting out the uterine cavity and its in contents from contact of external air and J other influences. a The increase in size of the os and cervix, ^ which is gradually progressive through the 1 wdiole of gestation, will be sufficiently ex- ]iressed by comparing the dimensions of these parts in their two extreme states. The virgin cervix measures usually at the base 7 — 8''' in its shorter, and 11 — 12''' in its transverse dia- meter, and has an aperture of 3 — i'" w ide. It projects into the vagina to the extent of F" (fig. 425). At the end of pregnancy, the whole vaginal portion of the cervix would fill a circle of 14" diameter; the orifice measures transversely 10 — IE"; and that part which formerly projected into the fornix of the vagina, is now reiluced nearly to the level of the vaginal walls. During these changes, it is often observed, esjiecially in a first pregnancy, that, as gesta- tion advances, the projection of the cervix 647 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. 7'he 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, otli edit. p. 128. Regarding this explanation, which had been given hy many preceding authors (see Jlauriceau, tom. i. p. 97. ; Smellie, vol. i. p. 183. et seq.), but which Gooch was, I believe, the first to illustrate hy 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. 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 a, of uterine body. The cervical canal is nearh' filled by the expanded palmse plicata;. Half the natural size. QAd 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 ancl 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 pregnane)', 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 canal is only an occasional occurrence, limited to the last stage of pregnancy, and liaving nothing to do with that a[)parent shoytening 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 [losition. On the occurrence of pregnancy, the organ, at first concealed within the pelvis, sinks, by its increased weight, lovver tlran usual within that T T 4 6-18 UTERUS AND ITS APPENDAGES. cavity ; anti, pressing upon the hhuhler ami rectnin, occasions .sometimes an irritable con- tlition of these |)arts. lint nsnally at tlie eml ot the tliird month, the fundus may he felt emerging fi'om tlie pelvic cavity ; and in the course of the fourth month, it is tdways easily di.stinguishahle in the lower part of the hy[jo- gastric region, having then risen to the height of about three fintrei s-hreadth above the pelvic brim. In the fifth month, the hypogastric region is completely filled ; the abdomen then actpuring a consitlerahle rotundity in this situ- ation. By the termination of the sixth month, the umbilical region also is filled, and the fundus uteri may he felt on a level with, or a little above, the navel. In the course of the renuiining three months, the uterus rises gra- dually, until its fundus reaches the level of the ensiform cartilage. And this is very nearly the 1 imit of its ascent, though it occasionally, and chiefly in first pregnancies, rises slightly above that point. In women who have a roomy jielvis, and in those cases where the natural form of the uterus is' not altereil by over-distension nor mal-position of the foetus, there usually takes place, a few ilays or shortly before labour, a certain descent of tlie uterus, which has the effect of partially emjitying th.e 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 deternuned by various circumstances; and it is interesting to observe in what way the addition of so large a body as the fully develo[)ed uterus to the already occupied ah- domeu, is jtrovided for, without any of the viscera suffering injurious [tressure, and with- out that ini|5ediment to the circulating and resjfiratory 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 obliiiuity 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 4-4'7. Positinn of the uterus ut the end of preynancy. (^After Maygrier,') 649 UTERUS — (Dkvelopmknt). therefore occupy a position midway between the spinal column and the posterior uterine wall. The pressure of the sacral promontory, and of the lumbar vertebree, 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 sjjace between the fundus of the uterus and the diaphragm, while the rest of the abdomi- nal viscera lie laterally and [josteriorly 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 lax, 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 jabout 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 jis towards the right. This obliquity in the position of the uterus may be caused bv an ■unequal length of the ligaments, or more com- monly by the projection of the lumbar verte- brre, 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 w'ould 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. W. 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 a[>pearance 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 showm by measuring the alse, or cutting them off, and comparing them with the sane parts in the unimpregnated state, when little or no difterence 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 iri'egular 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, hiive 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. Tne 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- clei (7%.434.),which constitute their embryonic 650 UTERUS AND ITS APPENDAGES. condition. These, up to the time of impregna- tion, form the special and sole elements of the muscular tissue ; yet some physiologists even of the present day refuse to recognise in these a muscular character, although it is 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- inenorrboeal membranes, anti the painful con- traotions termed uterine colic, prove that the unimpregnated uterus is so endow ed. 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 Kblliker, 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 contractile fibre cells, instead of a length of 0‘002 — O'OOS"', and width of 0'002"', in the fifth month, present a length of 0'06 — Q‘12"'', and width of 0'0025 — O’OOO'^', or even O'Ol'", and in the second half of the sixth month, a length of O’l — Q'25"'', a width of O'OOI' — 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 ])lace. This is ob- served, according to Kblliker, 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, Syd. Soc. vol. ii. ]). 259. ; and Siebold and Kbllilier’s Zeitschrift, 18d8, Lid. I. p. 72. ments, whose terminations become inter- mingled with the adjacent cells. Fine longi. tudinal markings are often distinguishable, and some fibres exhibit an elongated nucleus. The interior of the fibre is finely granular, and the margins show often a sinuous outline. Fig. 448. FiOi-e cells of gravid uterus fully developed. (^After Wagner.') The fibrous tissue uniting the several layers of muscles appears also to increase considerably, and towards the end of preg- | nancy to exhibit a distinct fibrillation. These muscular and fibrous elements of the gravid uterus are arranged in numerous ! thin lamellae, a good view of which may be i obtained by cutting a thin slice perpendicu- larly out of the walls of the uterus at term. ’ Fig. 449. Section of the entire walls of the uterus after deli- very; showing the arrangement of the lamina: and the divided arteries and veins lying between them. {Ad Nat.)* J By gentle traction, the laminae may be drawn partly asunder. They are then .seen to be t ii * In order to obtain a correct representatioo of n tbe 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 tlie stretching, the breadth of the preparation is doubled, and the laminae are separated and rendered more distinct. 651 UTERUS— (Development). most densely and closely united towards the inner and outer surfaces, but to be more easily separable in the centre or vascular laj'er, 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 wails, 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- m.inae. 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. Kblliker 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 may 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, notv\ithstanding their great 'ividth, instead of containing three, possess 'pnly one layer of muscular fibre, which, toge- her with the epithelium, composes the entire oat of the vein."^ , * Siebold and Kdlliker’s Zeitschrift, he. cit. p. 81. 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 neurilemma was the constituent tissue of the ganglia and nerves which chiefly enlarged during preg- nancy.” Dr. Ilirschfeld 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 w'hen 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, No. 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 Uteras,” 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: — I)r. Snow Beck, Philosophical Transactions, 1846, Part ii. p. 213. ; and Papers in the Lancet, vol. ii. 1856 ; .Jobert de Lamballe, “ Kecherches sur la dis- position des Nerfs de 1' Uterus,” Comptes Eendus, 1841, p. 882. ; F. M. Kalian, “ Die Nerven des Ute- rus” ; Zeitschrift, fur Rat. Med., Henle und Pfeufer, Bd. X. 1851; M. Hirschfeld, “ Note sur les Nerfs de rUterus;” Gazette Me'dicale, Oct. 1852, No. 44.; C. F. J. Boulhird, M.U., “ Quelques mots sur I’Ute- rus,” 1853. 652 UTERUS AND ITS APPENDAGES. or conductor of nerve force, the former pro- pert}’ 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 miilti|)lieil or enlargeil during the process of utero-gestation. Regariling a new formation of nerve centres, there is at [iresent 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 jilace 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 |)oint. Di-. Kilian dis- covered, that in the imimpregnated 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 [lale-margined fibre which traverses the tissues as a slender trans- jiarent band, has ceased to form a cylinder filled with nerve granules, and constitutes now only a |iale sleiuler 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 grailually more distinct between the muscular fibres, and at a later period many of the fine tubes become filled with metlulla, which was wanting in the unim|)regnated 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 mednllated cylinder is formetl, so that medullated fibres not only proceed as far as the uterus, but also become developed with continually increasing dis- tinctness during pregnancy betw'een the mus- cidar fibres. These observations correspond exactly with changes which Kilian observed to take |)lace also in young 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 develo[)ment of the animal pro- ceeds, so that the nerves may be said to grow forward in the direction of the uterus. It shoulil 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 contrarv, a law of gradual diminution of the nerve is found to obtain in ail cases, although the changes now described cause the rate of this to he different in the uniinjiregnated and gravid uterus respectively. Kilian had no op[)ortunity 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 liiiing membrane, and which has for its object the fonnation of an immediate covering and pi'otection 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 jrresence 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 tlie size of the uterus, than 'H takes place in ordinary gestation. The phenomena which ensue immediatel} * In a paper on the Structure of the Placenta, a by John Hunter, published in 178ti (Animal Kco- j nomy), the decidua is described as composed of || coagulahle lymph. In another paper, 179J, on “the case of a young woman who poisoned herself in the first month of pregnancy,” the pulpy substance i lining the uterus, into which the blood-vessels of ' the uterus passed, and upon which they ramified, 1 is stated to have consisted evidently of blood coagu- | luted. The statements and descriptions in these two ; papers constitute the basis of the Plunteriah hypo- ,i thesis regarding the source of the decidua. Hut I Hr. William Hunter had, even at that early period, ' a clearer perception of what the decidua really was, i for in his posthumous work entitled “AnAncto- inical Description of the Human Gravid Uterus,” j edited by Dr. M. Baillie in 1794, the decidua is de- scribed in the following phrases: — “This mem-,:, brane is an effloi’escence of the internal coat of tbe ^ 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 ot the lining membrane of the unimpregnated uterus, in the same way that the muscular coat of the gra- vid orgair is orrly a rrroi'e advanced condition of the |i same coat before irrrpregnation, is now proved he- yortd question. Upon this subject consult, in addi tion to the works quoted at p. 63C., Sharpey, in I “ Muller’s Physiology, by Baly',” 1837, p. D74. J H Eschricht, “ lie Organis quae Eespirationi et Nutri- tioni Fcetirs Mammalium inserviunt,” 1837 ; , , Kilian, “Die Structur des Uterus bei Thieren,” in,' Henie and Pfeufer’s Zeitschrift, bd. ix. ; Schr’oeder . van der Kolk, “ Waarnemingerr over Het Maaksel , van de Meirschelijke Placenta;” and Coste, “His- toire Ge'nerale et Particulifere du De'veloppement des Corps Organises.” 653 UTERU S— (Development). upon tlie arrival of tlie ovum within the ute- rine cavity are, in the human subject, as t et unknown. Direct observation of the earliest stages are still wanting, and, unfortunately, the difference between these first steps in the nianiinalia (except Qiiadruniana) 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 dosed cavity, forming a continuous structure with the decidua which lines the rest of the uterine walls. In 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 chandler 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 decitlua, the former constituting the decidua rejiexa, the latter the decidua vera of Dr. W. Hunter. For greater distinctness, those names are sometimes exchangetl for decidua ckorii or ovuli, and decidua uteri. The latter, accord- ing to a suggestion of Dr. M. Baillie, is also occasionally termed iiarietal decidua. At this time all the uterine tissues have be^un 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 fetus. 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 fetal chamber enlarges, and the decidua reffexa becomes more expanded in consequence 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 will 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 riatter and less regular than these ; between them are nume- rous little furrows or channels. The whole 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 cavil}', 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 refle.xa, is often thrown off entire, forming a Fig. 450. The entire decidua or lining membrane of the uterus cast off in abortion. (After U'. Hunter.) A portion of tlie specimen has been cut away to show the interior, wliich had formed the uterine cai-ity. 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 liaving 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 bad 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 ciub-shaped ele- 654- UTERUS AND ITS APPENDAGES. vations, and between these much smaller cnp- 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 there may be often seen lying within and among these orifices, fine, thread-like ramified filaments, which some physiologists su])pose to be utri- cular glands, or tbeir epithelial lining, now becoming loosened out and falling away, — a view in which my own observations do not enable me to coincide. See fig. 451. Fig. 451. External surface of the decidua vera, from an ovum of about two months ; showing the oblique channels in its substance. (^After Schrceder van der Kolh.) 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 [teriod, or the corresponding portion of the uterus from which it had been torn off. {Fig. 452.) These cells, or areolar spaces, continue to be seen, more or less distinctly, in the decidua throughout pregnancy, but are most conspi- cuous near the margins of the placenta. Surface of the decidua vera more advanced. (^After Schrceder van der Kolk.') It is here represented as still attached to the walls of the uterus after Ihe chorion, together with a layer of the decidua, have been peeled off from it. From a uterus at the sixth month of pregnancy, ju.?t 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, Jig. 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 refiexa, 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 (t%.450.), although it may also be found near the lower orifice ( Hunter, “ Gravid Uterus,” p/. 34., ji%. 4.), or elsewhere, appears at first like a small superadded cavity upon .he outside of the larger one, or that formed bythe parietal decidua. But as the development pro- ceeds, the fcEtal 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 pregn.Mcy, should be compared with figs. 438, 439. and 448., 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 thei-r 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,” “Lv’mpb,” and “Decidua,” ivhen so emplo^-ed, should be read as convertible terms representing the same part in different stages of development. UTERU S — (Development). uterine cavity, but the lower forms an attached base of greater or less breadth, which is conti- nuous in its entire circumference with the parietal decidua. The two chambers are totall}' distinct, and have no communication with each other. In aborted specimens, an aperture may be sometimes seen in the base or outer suri'ace 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 655 pole of the little spherical chamber, which have the appearance of apertures recently closed. Coste, in his beautiful series of illus- trations*, directs attention, in several figures, to a similar spot in the same situation, having the appearance of a recently closed aperture, or umbilicus. These traces of openings in both the upper and lower poles of the spliere, are of consequence, in reference to the expla- nation which will be presentl}' offered of the 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 ; shouting the formation of the fatal chamber by the decidua reflexa, more adoanced than in fig. 450. {After Coste.) «, uterine walls laminated and traversed hy 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 0, the ovum, at this stage often still unattached ; c, corpus luteum. smooth. Upon it, however, are seen the bilicus, but become more distinct towards the orifices of numerous uterine glands. These * Histoire Generate et Particuliere du Udveloppe- are usually wanting near the centre, or um- ment des Corps Organise's. 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 Hat vessels, obviously veins, terminating in minute subilivisions, are seen ramifying over the whole surface, but be- coming very scanty, or ceasing near the cen- tral point. Tliey 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 nnetjual, so as to form patches of a bright pink, alternating with other portions of a [>alc flesh colour. The internal surface of the fcetal chamber, after the ovum has fallen out, or has been re- moved, presents a slightly uneven appearance, occasioneil 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 hotly of the embryo begins to acquire length, the entire ovum exchanges the spherical for the slightly oval form, aiui to this tlie fcetal 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 fcetal 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, anil 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 (Jig. 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 serotiiia. Here the chorion villi, which now form large ramified groups, attach themselves, and from the margins of the collections of sidci 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 [dacenta. 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- cidiarities 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 |)eriod of pregnane^', 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 utricular follicles, and in growing there draws around it the already formed, but soft and spongy decidua constituting the walls of the cavity. The chief support for such a conjecture, beyond its apparent jjrobability, is the fact ascertained by Bischofl, 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 ]>rocess 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 fetal chamber, may mark the spot at whi' h, 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, suppo.sed 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 Kunke’s “ Lehrhuch | der Physiologie,” 18.o7, in which the same sugges- ' tion is ottered, exemplilied by the same ca.se, which, || indeed, is the only one yet known. 637 UTERUS — (Development). am satisfied that no such union takes place ; hut that, when the decidua i^flexa 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 filth or sixth month, so completely attenuated by distension from the growth of the ovum within, that it is reduced to a mere film, of whicli 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 co^i- 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 Histology of the decidua. {^After Schroeder van der Kolh.) 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 lorm fibres ; c, the same from an ovum of five weeks; a, round and oval cells, much en- larged, and containing nuclei and fat granulations from the surface ; h, 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 coipuscles or nuclei, contractile fibre cells, amorphous tissue aud epithelium, together w'ith capillary vessels, and the tor- tuous canals termed uterine glands. These undergo important modifications, which serve to explain the great and rapid grovvth 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 iu the form of oval nucleated cells {fig- “iS-f. B a), with fine nuclei and fat granules, b, 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. In 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 w'ere 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, wfiicli 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 trans[)arent, 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 ailvanced 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 638 UTEHUS AND ITS APPENDAGES. uterine walls; while, between it and thennis- cular parietes, there appears a new formation of deciilua, at first soft and delicate, hut which gradually ac(|uires the peculiar characteristics of that nieinhrane. This layer is not thrown off at birth, nor dispersed in the lochia, hut rejiiains attached to the inner uterine surface, anil forms the foundation of the new mucous membrane, with which, after labour, the ute- rus is furnished. M. Robin sui)poses that this new soft layer is often mistaken for a product of inllammation occurring in puer- peral and other uterine maladies. c. The uterus after parturition. [mmediately after labour, the uterus, if entirely empty, occupies the whole of the pelvic cavity, together with the lower portion of the hypogastric region. The bidk 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 scrum, 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 |)roper 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- ce|)t that the large and voluminous plic® (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 fmtal 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 [)lacenta had been attached forms usually one-third of the entire inner sujtcrfiiies 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, wdiose truncated orifices obstructed by coagula here protrude slightly above the general level. U]5on 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 Ileschl, Robin, and Kilian, hereafter quoted. tenet! 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 |)ortion 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. I Changes in dimensions and weight. — Accord- ing to repeated estimates made by Heschl, i the weight of the uterus, immediately after d labour, ranges from 1 lb. 6 — 7 oz., ordinarily, ' to 2 lbs. 3 — 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 eftected 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 undiininished, its length and breadth are greatly reduced, and the thickness of the parietes correspondingly increased. In one respect, however, the en- i tire bulk and weight are less than they were before labour, because a much smaller qiian- tity of blood now circulates in the walls, but the solids remain unaltered. At the end of thefirst week, the diminution of the organ is not very considerable. Its weight is merely reduced from 1 lb. 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, 3 — 6oz.; and in the course of the second month, it is reduced to its ordinary weight of fli 14 to 2§oz. ; but it never entirely regains the 659 UTERUS — (Development). small size and dimensions characteristic of the virgin state. ^letamorpfiosis 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 pari ^lassu with that of the foetus, 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 laminse, while the cervix remains unchanged a few clays 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, mmmonly arranged in rows. The nucleus of :he fibre is pale, but distinct, until it becomes obscured by the increase of the oil granules ; while the extremities of the cells, on account I On this subject the following may be consulted ivith advantage: — Dr. R. Heschl, “ Uutersuchun- ;en iiber das Verhalten des menschlichen Uterus ■ ach der Geburt,” in the Zeitschrift der kais. kon. lesellschaft der Aerzte zu Wien. 1852. B. ii. |.228. ; F. M. Kilian, “ Die Structur des Uterus bei : hieren,” loc. cit. ; Schroeder van der Kollc, loc. cit. 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 ; and 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 novv 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 (Jig. 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 observetl 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 6G0 UTERUS AND ITS APPENDAGES. the ciix'uniference of ;i 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 jdace; so that, several months after labour, a tumour of more or less consitlerable size, formed at the expense of the uterine tissues, is found to occujiy 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 wdiich are occasionally dis- charged from the uterus, and are regarded as moles. The hktological. 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 corres[)onding 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 surlace of the uterus is covered by a more or less red soft [mlpy 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 mucotis membrane upon tlie uterine body is effected. Betw'eeu 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, Schroeder 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- mencetl long before the retrograde metamor- [ihosis is complete, the result of both is, that a restitution or reconstruction of certain tis- sues of the uterus, more or less complete, i 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 j series of fibres for the purpose of effecting its j expulsion, anil 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 Jl place. The same may also be said of the , decidua, though with certain diff’erences as to | the time and mode of its destruction and re- j novation. Regarding the fibrous tissue of the I uterus, little has been determined with accu- I racy ; but enough has been observed to ren- | der it probable that this also, to a certain extent, becomes subject to fatty transforma- i tion. The blood-vessels appear to be likewise | partly involved in a similar process, although I 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 I' it must suffer a corresponding involution. Regarding the puerperal alterations in the nervous system of the human uterus, but little is known. Kilian f, after examining a spe- i 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 puer|)eral state, the nerve fibres undergo the same involution process as the other tissues; viz. that then 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. 661 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 tlie fibre are transformed in the same manner that Giinther and Schdn (Henle, Allgeineine 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 pari passu with the development of the other tissues. f. The uterus after the menstrual epoch, and 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- F/g. 456. The uterus in old age; showing a return to the infantine proportions between the hodg and cerrir. 0, the shrivelled ovaries. This figure exhibits the parts of half the natimd size. (Ad Nat.) tion to a size as small sometimes as that of a child of two or three years, (Jig. 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 thecavitj', 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 may often observe, therefore, in the uterus of aged persons, a nearer approach to the form of the equilateral triangle, caused bv 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 hi old age, and return to the triangular form of the cavity characteristic of the infantine (fg. 442.) and undeveloped uterus (fig.iGh), (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 chmiges are not limited to tlie Imdy 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 [irobe. Fig. 458. 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 arc maintained in their highest state of efficiency. The growth of the body is nearly or quite completed before the sexual offices commence, ami 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, wliich exert a powei'ful 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 botli 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 3’ears, 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- tariled, 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, mouatlicher Fhiss, and tlie 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 ; au 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 wdth 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 greatlj- influenced by climate, ttc., see Robertson’s Essaj’s and Notes on the Physi- 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, Ue la Menstruation, 1842 ; Raciborski, Ue la Puberte, 1844. 663 UTERUS—, 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 difterent 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 iqton the constitution, such as general pallor, and some feebleness of the muscular system. Nature 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 foetid 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 * Whitehearl, loc. cit. p. 24. t Brierre de Boismont, op. cit. p. 68. t De Mul. Organ. Lug. Bat. 1672, p. 13-^. (Functions). 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 o f menstrual fluid according to M. Denis. Water ----- 82-50 Fibrine ----- O’Oo Hematosine - - - - 6-34 Mucus ----- 4-53 Albumen - - - - 4.83 Oxide of iron - - - - Q-Oo Osmazome and cruorine, of each - 0-1 1 Salts and fatty matter - - - 1-59 Alicroscopic 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 di-aw 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 r.abies. — C. Plinii, Xat. Hist, liber vii. § xiii. ed. CuHer, 8vo. vol. i. Paris, 1827. U U 4 66+ UTERUS AND ITS APPENDAGES. decline, when the discharge loses its deep red colour and assumes the hue of water in whitli raw flesh has been washed. Tliis is very com- monly the condition of tlie discluirge 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 : l^f invasion. A very few blood globules mixed with mucus may be observetl, together with imicous-corpu.scles and scales of e|)ithelium, mostly entire, floating in an abun- dance of limpid fluid. Almost all the mucous- cor[uiscles contain smaller globules or granules which form in them a central nucleus. 2. Sla.tis. Menstruation havingreachetl its apogee, the blood-globules are much more numerous than at the onset. The plates of epithelium usually remain entire. .3. Decline. The fluitl contains the same substances, and |)resents nearly the same appearances as at the time of commencement of the How. These observations agree generally with my own, ami also with those of Donne, who found the menstrual Hnid to consist of, J. 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 rnenslnial fluid . — But in order to determine the nature of the menstrual Huid as it issues from the uterine oi'itice, unmixed with the secretions of the vagina, it must be collected by a specidum accurately fitting the uterine neck. The fluid so obtained possesses properties very tlifferent from those of the flux already described. Its sensible characters, as observed in more than a dozen specimens, are w’ell described by Mr. Whiteheail. Thus procured, the fluid is never so dark in colour as ortliuary 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 a|)pears 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 com[)lete in three or four minutes. It sometimes passes otf 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, a|)pear 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 Bonchardat are the more valuable. The woman, a mnlti- para, w'as thirty-five years of age. To explain the large proportion of water Bonchardat states that she had subsisted chiefly on a vegetable and milk diet. Bojichai-dat’s analysis of pure menstrual blood. Water - - - - - 90-08 Solid matter - - - . (j-92 The solids were composed of — Fibrine, albumen, colouring matter - 75-27 Extractive matter - - . 0-42 Fatty matter - - - - 2-21 Salts 5-31 IMucus ----.. 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 antem sanguis velut a victima, et cito coagu- latin’, si Sana fuerit midier.” 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 etfiision, con- sists of pure blood, mixed only w’ith 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 [U’esent, for these bodies exist in * Muller’s Physiology by Paly, p. 1481. t Traite des Mai. des Fern. Gross, p. 45. 3rd ed. 1681. 6G5 UTERUS — (Functions). large quantities in every instance of a Iiealthy menstrual flux. Source of the menstrual fluid . — The vagina, the os and cervix, and the body of the uterus, have been severally regarded as tlie 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 cervi.x 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. 3. 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 vei'v probable, from observing that, in cases of death during menstruation, the tubes as well as the uterus contained blood, which 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. 'file 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 view's, denominated a secretion. But since it is now know'n 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 phi sical and chemical constituents, until after it has become mixed w'ith other and adventitious matters. (b.) 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 walls 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 (flg. 439.), may be occasionally observed de- nuded, and hanging forth in detacheil 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 ca[)illaries is the conse- quence of a vital action, whereby a portion of the epithelial and mucous surfaces are broken * Histoire du Developpement, tom. prem., 1 fasc p. 209. 1847. t I am not prepared to assert that this condition is always present dirring menstruation, or that it is limited to such periods. A larger number of ex- amples than those iu 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. * Whitehead, loc. eit. p. 24. 666 UTERUS AND ITS APPENDAGES. down, and subsequently discharged, along witli the menstrual fluid. According to the observa- tions of Pouchet* * * §, such au e.xfoliation of ute- rine epitlieliuni 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 se[>aration 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 iutermenstruatiou. Such an exfoliation, if it extended only to the e|)ithelial cells sur- rounding the uterine capillaries, would simply leave them hare, hut 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 j%. 539.) lying iq)ou the face of this membraue, and consequently woidd leave a surface of torn capillaries, from which the haeinorrhage might occur and this in fact takes place in cases when dysmenorrhoeal membranes are discharged {fig. 443.). (rf.) The blood is supposed to escape by |)ermanent vascular orifices. In the present state of our knowledge, the evidence iii su|)port of this view is not more conclusive than that upon which the preceding hypothesis is built : yet many circumstances leml colour to it. The (|uestion of a termina- tion of the uterine vessels by open orifices has been occasionally, though obscurely, touched upon by different authors. Thus, Madame BoiviuJ, a most careful observer, after sjteak- iug of the “ perspiratory orifices of extreme minuteness,” visible upon the inner uterine surface, evidently meaning the orifices of the now well-known titerine glands, tiescribes the manner in which the blood may be matle, by pressure, to ap[)ear in droplets upon the inner surface of the uterus when death has occurred during menstruation ; and, without giving a per- sonal opinion, she elsewhere <|uotes 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 iletermine what is the precise re- lation of the blood-vessels to these orifices * The'orie Positive, Iliiitifenie Lni. t Pouchet, wtio does not enter upon the question of the effect whicli such a monthly denudation of the inner surface of tlie 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 tiux. Thus the idea of a sep.arative 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 Mem. de I’Art des Accouch., quarto ed. p. Cl. et seq. § Muller’s Physiology by Baly, p. 1.579. in the ileciiliia 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 in jecting 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 |)owerful mental impressions, acting ap|)arcntly upon the muscular fibre of the uterus ; while many positive facts might be adduceil in support of such a view, such as the frequent bleeilings 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. IVhaf. is the purpose of ■menstruation? — ToV 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 eyidence 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 dun 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 ; hut 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. Menstruation is not established until the^^ ovaries have reached a certain stage of de-Jy velopment, and the maturation and discharge ce M 4 19 * 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). 667 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 attenuateil 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 attem|>t at menstruation is ever observed ; while, on the other hand, in cases where the ovaries are present but the uterus is deticient, 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^, 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 ; hut 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 follow'ing 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 liave been already noticed, p 572. t See Mr. Pott’s case, p. 573. j JMegrier'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 In women who have died during a men- strual period the ovaries have been fretjuently observed to present unmistakable signs of the recent rupture of one or more Gi'aafian fol- licles. Some examples of this fact have been already given. In one case the ovum itself w’as found in the Fallopian tube (p. 567.).* Conception is supposed to take place most frequently within a few days after a menstrual ]ieriod, 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 CBStrus, or rut, in the mammalia, anil in them it is only during the oestrus that ova are emitted from the ovaries, and that con- ception can take [ilace. 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 afibrding 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 [irobabilities 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 graduall3' declined ; the whole process occupying generally from ten to twelve days. It happened, unfortunately, that in this case the uterus and va- gina were deticient, so that menstruation could not take place ; but the case in one respect is the more interesting on that account, for notwdthstanding 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 atfecting the organs wdiich were not malformed, were here unmistakable. Tliese circumstances forcibly call to mind the painful condition of the ovaries which, in a similar case, induced Mr. Pott to extirp.ate those organs. * Upon the connection between the discharge of ova from the ovaries, and the phenomena of heat and menstruation, the followdng should be con- sulted, viz. : — E. Home, Lectures on Comparative Anatomy, vol. iv., anil Phil. Trans. 1817 and 1819; Power, Essays on the Female Econom)', 1821; 7f. Lee, Cj'clopiedia of Practic.al Medicine, art. Ovary, 1834 ; Gendrin, Traite Philosophique de Medecine Pratique, t. i. 1839; IK. Jimes, Practical Observations on Diseases of Women, 1839 ; Paterson, Edinb. Med. and Surg. Journ. vol.liii; Girdwood, Lancet, 18-12-43 ; in addition to the works of Bis- choff, Raeiborshi, Negrier, Coste, and Ponchet, al- ready quoted under the title Ovary, p. 5(18., wdiere 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 tlie 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 I'clation which the oestrus, or pei iod 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 he 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 con.monly during the first week. In sixteen instances noted hy 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 uniiuestionably occur during this time, and even within a day or two of the next menstrual How, 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 uo evidence for its support. Nothing, in- deetl, is known regarding the length of time during which the human ovum remains sus- * Tliese and similar facts have been commonly regarded as showing a greater aptitude for concep- tion shortl}^ after menstrnation ; but the influence of mere opportunity has not perhaps been suificieutly considered; for if, as in the case of the Jews under the strict requirements of the Levitical law, the whole of the first w'eek, or that period which is commonly regarded as most fiivourable 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 coiiijileted in ten days. Ill 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. Rut by the time that the ovum reaches the uterus,or sometimes even thelower end of the oviduct, in most of the mammalia yet observed, the oestrus is past, and with it also the oijportunity 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 throngh the whole of a menstrual interval, consisting of twenty-three or more days, although the period of this susceptibility vta^ be longer in man than in the other examples cited. But if this first hypothesis fails, the second ajipears 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 perioils, 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 incompatihle with the facts already stated regarding the occasional, though probably rare occurrence of concejttion 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-1 siderable modification of the ovular theory ofJ menstruation. To account for impregnationj at a later period than usual of a menstrual in.J terval, M. Coste supposes that a ripe or dis-1 tended Graafian follicle, having failed in reach-T mg the point of ru|rture, may remain stationary,! as it sometimes does in mammals and that ■ the influence of the male is sufficient to de- termine the dehiscence of a follicle in such a1 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. — 51. Pouchet believes that a slender decidua is always formed at the decline of each menstruation, which, together wdth 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 w'omau remains ' incapable of conception until the next menstrual . period, wdien 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. 508. 669 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 i 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 ma}^ 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 w'ithin four days after the cessation of the flovv. 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 ! ^rst 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 case Ji/teen days had ela[)sed, 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 j precise times of the menstrual flow. But • until a larger number of examples than yet I exists, showing the condition of the follicles during both the menstrual periods and inter- I vals, has been collected and carefully com- ; pared, no definite conclusions as to the exact 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, w'hile mammals become impregnated only during the cestrus. It is important, therefore, to determine, thirdly, how far the cestrus or rut in the mam- malia may' be regarded as comparable with the act ofmenstruation 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 tw'O functions are compared, the more plainly does it appear that although the cestrus 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, loc. 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 CEstrus 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 oigan ceases to secrete semen. In this series of recurrent periods, marked by irresistible impulse, alter- nating with total inapjietence for congress, nothing is more evident than that each corre- sponds with an internal jiliysical condition, of wiiich it affords a most intelligible explana- tion. The appetency occurring and remain- ing only as long as congress would be fruitlid ; the inappetency returning whenever this would be necessarily infertile. Now, with regard to the human subject, whatever may be possible during menstruation, yet essentially tlie intervals of the menstrual acts are the times of fertility in women. And the only cjuestion that can arise uj)on 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 tlie emis- sion of ova and the act of menstruation in the human subject. But in res|)ect of the inter- val, the great divergence of the facts here dis- played tends to embarrass and perplex ratlier 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 shoidd be made between the infln- ence of the ovaries in determining the |)ower 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 regardeil as inilisputably 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 mahiration 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- [tregnation. The |)urpose of the flux 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 [)regnancy, lactation, or disease, once in every lunar mouth, 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-i 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- j verted to no positive use. No office can bei^ assigned to it, such, for example, as has been suggested for the analogous escape of blood iiito the ripe ovisac — an effusion that has been termed the menstruation of the follicle.* But although tlie blood, after it has passed i 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- asmia of the uterine vessels returns, and the ' overplus is emitted in the form of menstrual See p. 656. 671 UTERUS — CFl'>sxtions). 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 ofRce 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 — 4'". This dilated ex- tremity of the vagina forms a pouch which re- ceives the exti'emity of the introniittent 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 tlie 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 ofa 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 Blundell lias 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 tluid 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 (lown, 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. 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 ot the human uterus, which are normally in such close apposition that sections made in certain directions scarcely suffice to display any appreciable cavity (Jigs. 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 W'ay, contribute to this result, if those observations are correct which agree in assigning to them a movement such as wouhl 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 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 {Jig. 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 bodv 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. cif.-, see also p. 611. of this article. t See this article, p. 607. I Newport, Phil. Trans. 1853. Pt. II. p. 267. t 672 UTERUS AND ITS APPENDAGES. wliose free einls moving rapidly, cause the whole to rotate. A most remarkable object Fig, 459. Spermatozoa of Lumbrims agricola in motion and forming cilia. (Ad A’^at.') 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 s|)ermatozoa, 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 and 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 lie ge- neral in spermatozoa, 1 am not aware ; but the circumstance is altogether too remarkable to be passeil over without mention here, as it may serve to explain how the onward move- ment of spermatozoa can, in some cases at least, be aitled by this peculiar property of the spermatic fdaments 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. T/ic 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 anuonneed his discover}' 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 whose lectures on the invertebrata this account appears. Lectures on the Comp. Anat. and Phys. of the Invertebrate Animals, by llichard Owen, F.R.S., 2nd edit. p. 257. f See p. 009. the uterine cavity. If no such contact of the generative elements as is necessary to the deT velopment of the ovum takes place, then the latter suffers no further change beyond that slight alteration in its condition during its ' |iassage through the oviduct, which has been . already describeil ; and ultimately it becomes lost, probably suffering decomposition, but at’ j least giving no evidence of its presence in the uterine cavity. But if the ovum has been fer- tiliseil, then commences that remarkable series of changes in the jjhysical condition of the uterus whereby this organ is fitted for the pro- tection and nutrition of the ovum during the tisual period of forty weeks in which the latter is normally retained within its cavity. As these changes involvevery 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.). Fhe office of the uterus in jjurturilion. — The act of parturition, or that ()rocess by which, in normal cases, the product of conception, after due development, is spontaneously sepa- rated anil expelled from the parent body, con- stitutes the last chief office of the uterus. I The labour process may be regarded as es- » sentially a contest between two opposing forces, which are resisting on the one hand,^; and pro2)ulsive on the other. Resistance is f '1 necessary to preserve the foetus in its place^y- Projndsion is reipusite to detach and expel it ^ froni 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-jT tures of the |)elvis 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, is or under any impnlsive movements of the, parent body. Their combined resistance is such j, as to require the operation of powerful mus- , ' cles to overcome them before the child can be#, expelled. This power is supplied by the uten.'s, 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 pre|)onde- 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, caeltris paribus, natural. Whenever they are greatly 1 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. j * The meclianical operation of the parts con- cerned in labour having been reserved for con- j; UTERUS — (Funct ions). 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 oflered 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, tbe 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 (Parturition, Mechanism of, Vol. III. of this Cyclopaedia), the vital endowments onlj’’ of the uterus, as far as these relate to the parturient act, are here examined. * Wigand, Die Gebui't 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, 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 which 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- low'ed 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 07+ 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- aai[)le, of cyprinus, the [lart 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 striatecl muscular fibre ensue.* In the same way the peristaltic action of the uterus, although exhibiting certain ditferences, 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 i)rinci[)ally 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, I3 ing 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 tlje action that ensues, will be, to a certain extent, dependent iqjon 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 the.se 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 feetus, 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 Muslieliewegung, in Wagner’s Ilandworterbuch. 1856, It is in favour of the views of Wigand, who | maintains that uterine action begins at the I cervix, and travels upwards, that the cervix! receives a larger supply of nerves than thej fundus, so that the action may be here first | established, and the fundus afterwards ex- 1 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, 3 irregular action and spurious pains ensue. B 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 Us 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- 1 seating part of the child. These occur-* rences do not commence coincidently, butU 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 v 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 I 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 — (Functions). force, for it is beyond question a healtliy ne- cessity which, for tlie jnirpose of advancing the process, demands this graduated change of the uterine rythm throughout labour. Rythin plainly does not, like peristaltic action, depend upon the structure of the organ w hich 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 de[)ends, 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 ry thins 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 I rythmic motion, though they may still be C75 artificially exciteil to repeated single ac- tions.* Rut 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 ap|)lication of tiie excitement. In this way rythm, so far as it is dependent upon nervous supply, is a[i- parently determined. But in the case of the uterus w'e observe that the rate of the rythm must be to a cer- tain extent limited by the |)eculiar 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, or a rithmic 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 ei got. 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 whicli 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 Kiwisch, 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, Crooniaii Lecture; Proceedings of Roy', Soc. vol. viii. No. xxvi. ■ 1857. X x 2 I 670 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 coinnnmieation 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 inal cord, it becomes finally ejected ; so the ovum is itself ajqiarently 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. AiiNon.iiAL Anatomy of the Uterus. A. Defective develupmcnt. — Imperfect or defective development of the uterus may oc- cur under two circumstances. There may be either an original defect in its organisation, arising li'om 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 passed. \st Class. Congenital defects. — Defects of this class may afl’ect 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. a, uterus; h, round ligaments; c, Fallopian tubes; d, ovaries; e, remains of Wolffian bodies. the inferior extremities of the ducts of Mid- 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 tbe malformations of the uterus which are dependent upon original vices of formation may be arranged in four groups, viz. : — Group I. 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. G42. C79 UTERUS — (Abnormal Anatomy). lined by mucous membrane. This constitutes the condition designated by Mayer the uterus bipartitus. 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 e.Nternal organs may be well formed, and there may be no deficiency of sexual charac- 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 boilies and e.xcretory duct of the generative apparatus are developed, yfg. 400. and 416., so that the failure in growth of 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 unicorms 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 e.xtremity 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 an_v, 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 tw’o 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 w'alls. 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 (y?g. 4GI .). 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. Rokitansky* 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 bodv of the uterus forming two cornua, which are still nearly horizontal, but .are united by a commissure at a higher point than in Jig. 461. ([uently the relative mutual position of the two uterine halves. The nearer the point of co- See Fallopian tube, p. 61.3. Loc. fit. p. 274. X X 4 C80 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 fissui’e (Jig. 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 re|)i esented in _/?g«.462. and 463. ^nfg. 462., although the commissure is placed at a higher point than in Jig. 461., so as to be much fLirther removed from the external os, there is still a considerable separation of the two cornua, and their direction is still mainly horizontal ; but \njig. 463., where a more per- fect coalescence of the two halves has taken Vig. 463. The cornua more completely united extemalh/, and the two halves hecominy 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 se()tmn which descends to a variable depth, and exercises a corres| end- ing inHuence upon the separation of the two halves. In cases where the commissure representing the fundus 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 downw'ards 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 Jig. 463., the separation of the two uterine halves is more complete, but there is still a common os externum, leading to the tw'o canals. The highest de- gree of division, and consequently lowest type of stiucture, is that in which the septum ex- tends not only through the cervix, but even to the extremity of the vagina, dividing the latter, 46 1 ., 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 |ioints 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 po.sterior uterine wall, may indicate the seat of that in- ternal vertical septum which more or less completely divides the uterine cavity into two halves, ami constitutes the uterus bilocularis (fig. 464.). Fig. 464. The body of the uterus showing only a slight indenta- tion externally. (After Busch.) An internal septum e, divides it into two loculi, a and h. 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 wdl 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, ami distending the closed sac forms there a haematometra.* Where the parts rej)resenting the uterus are entirely solid. See p. 697. 681 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 devil, 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. Tbe 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 bv only one set of vessels, the course of the pregnancy will probably suffer in a corre- sponding degree. 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 ill both. There is even reason to suppose that twins have been developed in one half, and also that superfaetation 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. imrturition, 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 right 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 fcEtus 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 womb, 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 puherty has arrived. The cavities of the body and cervix are laid open. (^Ad Nat.) a, cavity of the body retaining the triangular form and the lines or rugfe characteristic of infancy ; b, the cervix, the extent of which is indicated by the penniform rugae ; c, anterior lip of the cervix ; d, ovaries ; e, Fallopian tubes. From a female aged 19, who had never menstruated. (Compare with ^3. 442., repre- senting the uterus of an infant. Both these figures are of the natural size.) passed, and yet no corresponding enlargement or growth of the uterus may have taken place; * See a remarkable case of pregnancy in the rudimentary half of a uterus unicornis, ending in rupture of the sac and death in the third month, by the organ retaining the form and size which Rokitansky. (Pathol. Anat. Syd. Soc. vol. ii. p. 277.) The preparation is preserved in the Vien- nese Museum. * Loc. cit. 682 UTERUS AND ITS APPENDAGES. characterise it in infanc_y or childhood. Such may be the condition of the entire internal organs, as in tlie accompanying example (fig. 465.) of the undeveloped uterus from a female aged 19, who had never menstruated. In these cases, the body generally exhibits a corresponding feebleness of growth, and the sexual attributes are little, if at all, dis- played. The infantine condition of the uterus is here exhibited in every particular. The proportionately large size of the cervix, b, the small triangidar uterine cavity, a, with a raphe extending into it, and the thin parietes, are precisely such as are usually found in the infantine organ. In the last case, the ovaries exhibit also their ordinary infantine proportions ; but these may become developed, and the func- tions of menstruation may proceed naturally, svhile the external characteristics also are those of a well-formed female, but the uterus remains small, the vagina is short, and instead of terminating in the usual fornix, with a pro- jecting cervix, this canal ends in an aperture, which just admits a sound or probe, and is not furnished with the usual lips of the os tincse. These cases usually result in sterile marriage, and may be easily detected during life. Anomalies of form. — Deviations from the ordinary form of the uterus which are ac- quired during life, and do not proceed from original malformation, or imperfect develop- ment, such as that last noticed, will be here considered. The angular flexions of the uterus which lake the definite forms of a forward or back- ward curve, or of an inflexion towards either side, are distinguished as anti- and retro- flexion and lateral inflexion. a. Antificxion of the uterus is that condition of the organ in which, without any material change of position in the cervix, the body is bent forwards, so that the fundus, lying more or Fig. 466. Anliflexion of the uterus. (After Boivin and Duejes.) The point of flexure is at the junction of the body with tlie cervix. Botli canals are laid open. (The ligure is viewed from the right .side.) less horizontally, is directed towards the sym- physis pubis, while, according to the degree of inflexion, the anterior wall of the uterus is brought near to, or in contact with, the cervix in front, while the posterior wall looks up- wards, corresponding more or less with the plane of the pelvic brim. The point of cur- vature is always at the line of junction of the body with the cervix uteri, and here an angle more or less acute is formed. Fig. 466., giving a lateral view of the anti- flexed uterus, exhibits the relative situation of its various parts when this deformity exists in the highest liegree. Kow a slight amount of antiflexion of the body upon the cervix has been shown by figs. 426. and 43.3. to be natural to the uterus ; and it is not until one or two pregnancies have supervened, that this forward tendency, when excessive, is lost, and hardly even then, for the uterus may still retain that correspondence in form, with the curvature forwards of tlie pelvic cavity, which is so prominently ex- pressed in the curve of the sacrum, and is in accordance with the normal form of the ute- rine canal. In the foetus (fig. 46?.), and ! during early infancy, antiflexion exists as a Fig. 467. Natural state of antiflexion of the uterus in feetiil and infantine life. (After Bourgery.) a, body, and h, fundus of the iiteras ; c, point of junction of body and cervix ; d, cervix ; e, os tinea* ; f, vagina ; g, liyinen ; j, bladder ; h, rectum ; I, fal- lopian tube ; n, symphysis pubis ; m, labium. normal state, and it appears to me that this bias towards a forward inflexion ot the uterus ■ at the early periods of life is given by that *■ remarkable bending forwards of the lower ex- tremity of the spine which is observable in the early embryo. The part containing the structures that are afterwards developed into the uterus exhibits then an abrupt curve, which at this early period will probably be impressed upon the organs within, and being abnormally 683 UTERUS — (Abnormal Anatomy). retained by them after the pelvis has changed its form, may give rise to the malformation under consideration.* b. Retroflexion exhibits the converse pecu- liarity, the body of the uterus being bent back- wards upon the neck at such an angle that the fundus occupies a position more or less deep between the cervi.x and rectum, filling and distending the pouch of Douglas. This condition of the uterus ought not to be con- founded with retroversion or with those retro- uterine tumours produced by inflammation, and effusion into the cellular tissue (fg- 433., g) at the back of the cervix, of 'which an account will be presently given. See p. 688. c. Lateral inflexion. — The uterine body ex- hibits occasionally an inclination to lateral curvature, so that the fundus is directed to- wards one or other side. A curvature out- wards, in the form of an arch more or less deflected from tlie meridian, has been shown to be the usual condition of the uterus uni- cornus. But where a tendency towards either side is shown in the otherwise normally formed organ, this appears to arise from some inequality in the development of the two uterine halves; or it may depend upon one half undergoing hypertrophy, so that in either case one uterine angle lies higher than the other, and a vertical line would divide the organ into two unequal parts. The cervix is here curved as well as the body, or the latter may remain perpendicular while the body is bent so as to form an angle with the cervix. The former variety has been designated the retort-shaped uterus. Anomalies of Position. Obliquity of position, Hysteroloxia, ISIetro- loxica, Obliquitas uteri. — The foregoing defects should not be confounded with those devia- tions in position, without alteration of form, which constitute the various obliquities of the uterus ; — like the inflexions of the uterus they are distinguished according as the organ is directed forwards or backwards in the median line, or laterally in the transverse diameter of the pelvis. a. Anti- and retro-versions. Situs uteri obliquus anterior et posterior. — Anti-version of the uterus is by no means so common as retro- version. Both affections differ from the cor- responding anti- and retro-flexions of the organ in this respect, that while in the two latter cases the point of flexion is usually at the seat of junction of the body with the cervix uteri, in the former the uterus remains straight or nearly so, while the entire organ is directed forwards or backwards, and the seat of flexion is at the junction of the cervix with the va- gina. The dis[)lacement of the uterus is here far more considerable than in the former cases. In anti-version the degree of uterine dis- * See a paper in the Trans. Micr. Soc. vol. v. pl._7. ; Quarterly Journ. Microscop, Scien., July, 1857, in which I have figured a human embryo of four weeks, exliibiting this peculiarity in a marked degree. placement is limited by the bladder and an- terior wall of the pelvis, which generally prevent the fundus from sinking so far for- wards, as to give the entire uterus in the uniinpregnated state more than a horizontal direction. An extreme degree of anti-version however sometimes occurs at an advanced period of pregnancy in multipart, on account of an unusual laxity of the abdominal walls permitting the whole uterus to fall forwards, so as to occupy the artificial pouch formed by the pendulous abdomen, the fundus filling the bottom of the pouch, while the cervix and os uteri are tilted upwards and backwards, the latter being lifted out of the pelvis, and point- ing above the promontory of the sacrum. This malposition materially impedes labour by' reversing the natural direction of the uterine axis, so that the propelling force is expended upon those parts that lie opposite to the os, and the fcEtal head is prevented from entering the pelvic brim. Retro-version occurs in conditions of the uterus otherwise normal, or it may' happen when the organ is enlarged by disease or preg- nancy. When unimpregnated the displaced organ lies entirely, and when pregnant chiefly', within the pelvic cavity. In retro-version, on account of the excavation of the sacrum, the fundus readily descends so low as to admit of the normal relations of position of the os and fundus being nearly reve.'’sed. The latter being directed downwards and backwards towards the coccyx, while the former is tilted upwards Fig. 468. Retro -version of the uterus. (^Diagram.^ and forwards, so as to lie behind, or in ex- treme cases above, the symphysis pubis. In extreme retro-version a line drawn through the uterine cavity' would represent nearly the normal axis of this organ, but instead of pass- ing out backwards through the posterior cer- vical wall, it will pass out forward through the anterior wall, because the stretching of the vagina in these cases will cause a slight degree of flexion of the cervix downwanls. The sequels of this displacement in the case of the gravid uterus, when artificial or spon- 684 UTERUS AND ITS APPENDAGES. taneous reposition cannot be effected, are usually |)remature expulsion of the oviun or sloughing of the uterine parietes and slow discharge of the contents by fistulous open- ings into the vagina, rectuin, or other parts. b. Hernia of the idenis. Hi/sterncele, Me- trocele. — This dis[)lacement is rare. The uterus may escape from the pelvis by some of the natural openings which ordinarily ad- mit of hernia, or by an aperture artificially formed, as, for example, between the muscular fibres of the abdominal walls. In uterine hernia, the displaced organ is often accom- panied liy other [larts, almost always by its own appendages, and commonly by a portion of intestine, or omentum. Uterine hernia may be congenital or acquired. It may occur to the unim|)regnated or the gravid organ, and in the latter case the development of the foetus may proceed to the full extent while the organ occupies tins unusual situation. A careful examination of the recorded cases of uterine hernia leaves it doubtful if the pre- cise form of the hernia has been, or indeed could be, determined in every instance. Ventral hernia has been observed only of the gravid uterus, which may become, in part at least, included in a large umbilical hernia, or it may result in cases of separation of the recti muscles where the uterus has ascended sufficiently high to fall forwards over the brim of the pelvis. And it has been supposed to occur after the cicatrisation of a supra-pubic abscess, and as a consequence of a Caesarian section. Of crural hernia an interesting example is given by Lalleinand *, in a woman aged eighty- two, whose body he examined. The hernia appeared at the age of forty, after labour. It remained as an irreducible tumour in the right groin, and was twice accompanied by symp- toms of strangulation. After death, the sac of the hernia was found to contain the uterus, ovaries. Fallopian tubes, and upper part of the vagina, together with two folds of omen- tum. Inguinal hernia. — Chopart f relates a case of hernia in which the uterus with the Fallo- pian tube and left ovarium occupied a sac be- yond the inguinal ring. The uterus was small, flabby, and elongated. Lallemand % gives a corresponding case where the uterus and right tube and ovary were found in a hernial sac on the right side in a woman who lived to the age of seventy-one. The most remarkable examples are those in which the uterus either became |)regnant while so situated, or was protruded during pregnancy. In two examples of this kind, related by Sennert, the precise nature and situation of the hernia is, perhaps, doubtful, but they are nevertheless very interesting. In the first, a swelling in the left groin followed the blow of a stick. Soon the swell- ing expanded, and it became in time evident * Bulletin rte la Fac. de Med. tom. i. 1816. t Boyer, Traitd des Mai. Chir. t. viii. p. 381. j Mdm. Soc. Me'd. d’F.muIation, S™" Ann. p. 323. that this was caused by the presence of a gravid uterus. The tumour, covered by inte- gument, hung forward hke an oblong gourd; by degrees movements of the foetus were per- ceived, and the woman having at length reached her term of pregnancy, the integu- ment and uterus were laid open, and the child and placenta extracted. In Sennert’s second case, some injury had been received in the first confinement, but it was not until after the ninth delivery that a swelling appeared in the left groin, and gra- ' dually increased to the sizeof a cow’s bladder; finally it hung down to the knees. The tu- mour was opened, and a living child extracted. Both cases ended fatally to the mothers. The best authenticated case is one which occurred at Salamanca, and is related by Pro- fessor Ladesina. A woman, age 42, mother of seven children, and the subject of an irre- ducible inguinal hernia, when 3 to 4 months pregnant experienced a sudden increase of the tumour after stooping. The swelling, now of a different consistence, could not be reduced, and after a time fcetal movements were perceptible within it. Labour ensuing in the usual way, the liq. amnii escaped per vaginam, but it was necessary to extract the child by incision into the sac. The tumour contracted ultimately to the size of an ordi- nary scrotum, anil formed a permanent hys- tcrocele in the inguinal ring.* In addition to these forms of uterine hernia, a partial displacement of the organ through the obturator foramen or ischiatic notch ap- pears possible. This latter is distinguished by the not very appropriate title of hernia dorsalis uteri. Prolapsus. — Palling of the Womb. — Beanng down. — Two degrees of this displacement are recognised. In the first the uterus occupies., a situation lower than usual, the cervix rest-'^ ing upon or near the floor of the pelvis, yet without any protrusion of the organ exter- nally. In the second, the uterus is protruded partly or completely through the vulva. The former is distinguished as partial, and the latter as complete prolapsus or procidentia uteri. Prolapsus in the first degree is not neci s- sarily accompanied by any material change in | the condition of the uterus itself. The fol- | lowing alterations, however, in its relations i to surrounding parts usually result. The whole organ occupies a lower position than usual in the pelvis. The vagina is more or less completely filled, its upper partbecommg folded upon itself like the half inverted finger of a glove. The cervix is abnormally directed forwards. The uterine appendages become in part displaced in following the descent ot the uterus, while the neck and posterior wall ‘jj of the bladder, and sometimes a small portion of the rectum, are likewise drawn down on account of their attachments to the cervix uteri. • ,1 f In extreme prolapsus or procidentia, the Edinb. Month. Journ. Pt. vii. 1841. 685 UTERUS — (Abnormal Anatomy). entire uterus, or a great portion of it, hangs forth beyond the vulva, forming there a pyri- Fig. 469. Extreme prolapsus or procidentia uteri. (^Diagram.') form tumour of considerable size. At the bottom of this is the os uteri, greatly exceed- ing in dimensions in chronic cases the ordi- nary condition of the part. {Fig. 472.) The lips are swollen and hypertrophied, and usu- ally present a sore and granular surface on account of the friction to which they are con- tinually exposed. The external covering of this tumour, in all but its lower part, consists of the inverted vagina, the horizontal rugse of which are very conspicuous anteriorly between the cervix and pubic arch, where a fluctuating swelling is observed, caused by the presence of a portion of the displaced urinary bladder. {Fig. 469.) In chronic cases the surface of the inverted vagina gradually loses the character of a mucous membrane, and puts on the or- dinary appearance of common integument. After replacement, however, an extensive shedding of epidermal scales ensues, and the surface resumes in time the condition of a mucous membrane. In cases of great elongation of the cervix, the latter alone may protrude, while the body of the uterus remains within the pelvis. Such a combination of hypertrophy with dis- placement has passed with the ignorant for an example of hermaphrodite formation. Prolapsus is the most common displace- ment to which the uterus is subject. It is frequent in multipart, and in women who follow fatiguing occupations, especially those of a relaxed habit of body ; but it also hap- pens in nulliparae. In the latter, when it occurs at an early period of life, it is often associated with enlargement of the uterus or its appendages, whereby both the weight of the organ is increased, and a broader surface is offered for pressure from above. Elevatio uteri. Dislocation upwards. — This is the converse displacement to the foregoing. The uterus, in consequence of some enlarge- ment of the parts appended to it, as the ovary, or on account of the formation of morbid ad- hesions, may be drawn upwards to such an extent that no portion of it, or only a part of the cervix, is retained within the pelvic cavity. This displacement is also occasionally ob- served during pregnancy, and in multiparae, w hose abdominal walls are relaxed, and permit the uterus to incline forward, so that at the beginning of labour the os cannot be reached by the finger. Inversion. Eversion. — The uterus, either in the unimpregnated or gravid state, may become partially or completely inverted. The conditions which appear ordinarily to com- bine in producing this displacement, are, first, a distension of the uterine cavity*, as by pregnancy or the presence of a tumour ; and secondly, a force applied in the way of pres- sure from above, or traction from below, whereby the distended uterine walls become folded within each other, somewhat after the manner of the intestinal walls in intussuscep- tion. Inversion of the uterus appears always to begin at the fundus which is first depressed into the uterine cavity, and then, under the continued operation of the disturbing forces, the part is gradually protruded through the cervix and os uteri, 470., until it emerges in an inverted form into the vagina followed by the reversed walls of the uterine body, and ultimately by those of the cervix. The inver- sion of the uterus is now complete. The greater part of the organ lies beyond the vulva as a pyriform tumour, the base of which, formed by the fundus, is below, while above the narrower neck of the tumour consisting of the inverted cervix lies in part within the vagina, the up- per portion of which canal is also drawn down and partly inverted. The vagina is thus ma- terially shortened, and terminates in a cir- cular fold marking the point of reflexion or inversion, while the usual seat of the os uteri, which is necessarily obliterated, is occupied by the now inverted cervix {fig. 471.). Inversion constitutes the highest degree of displacement of wdiich the uterus is suscep- tible, for it is both prolapsed and inverted, so that the relative situation of the entire organ to surrounding structures, as well as of all its parts to each other, is completely changed. Inversion does not, however, always proceed to the highest degree, but may stop short at any of the intermediate stages just described. When inversion occurs to the gravid uterus, the accident usually happens during the ef- forts of the organ to expel the placenta. In this way, inversion may occur spontaneously, or it may be favoured or produced by injudi- cious attempts to extract the placenta, or by too much traction applied to the funis. In the unimpregnated uterus, a polypus attached by a stem to the fundus ma}' by its weight slowly produce the same results. That a sudden and spontaneous inversion of the un- impregnated uterus is possible, was proved to * Boyer, and some others consider that disten- sion of the uterine cavity is not an essential pre- liminary to inversion. 68(i UTEUUS AND ITS APPENDAGES. me ill a case which I witnessed of an aged verted liuring a convulsion. In tliis instance, woman wliose ntems became completely in- the onl}' apparent predisposing cause was the Fig. 470. Incomplete hwersion of the uterus. ( After J. G. Forhes.') - Tlie fundus is beginning to protrude throiigli the os uteri, dragging after it the Fallopian tubes, which I are drawn into the hollow formed by the inverted organ. ij dilatation of tlie uterine cavity by a tumour tlie size of a flattened apricot, which was e.x- pclled at the moment when the uterus came Fig. 471. Complete inversion of the tderus. {Diagram.') down completely inverted, — the violent ac- tion of the abdominal muscles and diaphragm probably here producing or aiding the ever- sion. After complete inversion, the uterus may remain incapable of replacement. Under these circumstances, the external surface of the protruding portion loses much of its original character of a mucous membrane, and be- comes covered by a thicker epithelial layer. It continues, however, more vascular than the surface of an ordinary procident uterus, and is especially liable to abrasion and ulceration,, from the friction to which it is exposed. Wlien this displacement occurs during men- strual life, and is permanent, tlie menstrual fluid may be observed at the periods exuding from the surface of the inverted organ. The internal relations of an inverted uterus dejiend upon the extent of the inversion. In extreme cases the interior of the tumour con- sists of a sac lined by the peritoneum, which originally formed the outer covering of the uterus. The centre indeed of the broad liga- ment may be said to be inverted so as to form a pouch in which are contained the Fallopian ’ tubes and ovaries, and occasionally a portion of small intestine {Jig. 471.). In minor degrees of inversion the uterus , remains within the vagina, and the peritoneal “ pouch in its interior contains only the roots i of the uterine appendages {Jig. 470.). Anomalies of Size. a. Atrophy. — Under this head maybe in- ^ eluded those examples in which the uterus appears to have been originally well deve- loped, but has since suffered atrophy of its tissues. Such cases are to be distinguished on the one hand from the imperfectly deve- ' loped and prepubertal forms already described ; , and on the other from examples of senile I atrophy as it occurs in its ordinary course. I Whenever atrophy attacks the uterus before the climacteric change the condition is to be deemed abnormal. Such a wasting may affect the entire uterus or some of its parts. In either case the tissues become pale, soft, and nearly bloodless. In atrophy of the uterine C87 UTERUS — (Abnorjial Anatomy). body the walls may not exceed in thickness or density those of the urinary bladder. Such a condition may occur under dilatation of the uterine cavity, whicli however is more com- monly attended by an increase in the thick- ness of the uterine parietes. The atrophy of the uterine walls which is accompanied by dilatation of the cavity, is distinguished as excentric, and that which occurs in combi- nation witli a diminished cavity as concentric atrophy. Atroph_v of the cervix may be combined with partial atresia of its canal, and is often associated with some malposition or morbid growth of the uterine hotly or its appendages. b. Hjjiiertrophy is of far more frequent oc- currence than uterine atrophy. According as this condition affects the entire uterus or only ■some of its parts, the organ either presents the ordinary figure but upon a larger scale, or else a greater preponderance is given to one portion, so that the uterus becomes malformed. Hypertrophy of the entire uterus commonlv I’esults from frequent pregnancy, from the growth of tumours, or from accumulation of ffiiid within the cavity. In the latter cases the uterine walls may acquire the same thick- ness as in pregnancy — and the hypertrophy is due also to the same cause, viz. to a deve- lopment of smooth muscular fibre, such as ordinarily 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 be a constant sequence. Ilere the hyper- trophy produces usually a uniform enlarge- ment of both lips, which form together an annular tumour divided transversely by a wide os tincae,_^g, 472. Fig. 472. But the cervix may become hypertrophied in the longitudinal dii’ection also. From this there results a remarkable elongation of the uterine neck, which may protrude to a con- siderable tlistance beyond the vulva without a corresponding degree of displacement or de- scent of the body of the uterus. In the ac- companying illustration, 7%. 473, the manner of grow'th of the elongated cervix is showm. The body of the organ being only partially displaced, a gradual addition to the length of Fig. 473. Elongation of the cervix uteri from longitudinal hy- pertrophy. (^Ad JVat.) /.fundus; fo, internal os uteri; cc, cervix; va, vaginal walls. the neck occurs until the vaginal portion pro- trudes at the vulva. The canal of tlie 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 fig. 472. Among the anomalies of size may also be included those examples of imperfect involu- tion of the uterus after pregnancy, in whicli the organ retains for several months the or- dinary' size characteristic of it shortly after labour. Pathological conditions of the separate tissues of the 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) the subperitoneal tissue; (3) the parenchyma; and (4) the mucous lining of the uterus. 1. Pathological conditions of the 2^(’i'itoneal coat. a. The external position of the peritoneal coat, and the small amount which it con- tribute.s to the bulk of the uterus, combine to 688 UTERUS AND ITS APPENDAGES. render tlie morbid conditions of this coat, re- garded singly, of less pathological importance than the abnormal states of tlie other tissues. The pathological conditions of the serous coat are chiefly those of acute or chonic meiroper'i- tonitis, terminating often in exudative processes and the subsequent formation of adhesions be- tween those portions of the uterus which are invested by |)eritoneum and adjacent struc- tures, such as the Fallopian tubes, ovaries. Jig. 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 atrojihied, 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 [jroceeded 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 suh-peri- toncal fibrous fisstie. a. Perimetritis. Partial chronic wetritis. Peri-uterine 'phlegmon. lietro-idcrine 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 ap[)arently 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 terra '’'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 yjcnwc/rfa/. In this article, however, inflammation of the subpe- ritoneal fibrous tissue will be designated peri- metritis, while inflammation of the peritoneum * Monat, Observation Medicale (Gazette des Hopitaux, 18.50.) Bernutz et Goupil. Reclierches Cliniques siir les Phlegmons peri-uterines. (Ar- chives Geiierales de Blddecine. Mars 1857.) 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 (/g-. 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 i /?g. 426. b b, and fig. 433. f.). ^ The anatomical conditions of these peri- nietrial 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 r. 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, byphj'sical 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. I The surface of the tumiour towards the tec- | turn, upon which it encroaches, is convex, ' and is either smooth or irregularly nodulated, |i while between the tumour and the neck of the uterus is usually perceived a notch more j 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 1 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 i Justify here a brief exposition of the peculiar j. anatomical condition and relation of parts which ,1 appear to me to conduce to its production.^ From the view of the pelvic viscera given in ' I" * I believe that it is often confounded not only ' i, W’ith retroflexion, but also with retroversion, fibrous tumour, and hypertrophy of the posterior uterine || wall, and tliat hence the frequency of its occur- rence has not been commonly recognised. ; It 689 UTERUS — (Abnormal Anatomy). {jig. 433.) it will be seen, that while the normal cervix projects obliquely into the upper part of the vagina, the fornix 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 [iressure, 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 some 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 {mar- cidifas}. In these cases the texture of the uterus may be pale and exsanguine, or in a state of hyperremia, with occasionally apo- plectic effusion. Rokitansky associates the latter condition with thickening, and some- times ossification of the uterine arteries. b. Parenchymatous injlammation of the uterus. Metritis. Metritis parenchymntosa. — 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 vessels 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 oedematous 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 maiter 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 commoidy the cervix is principally or exclu- sively involved, and the resulting enlargement is especially observable in its vaginal portion, the lips of w hich 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 fbrosus uteri. Fibro- muscular 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- conling 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 ■}- 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 ba.sis substance, which in these uterine formations has always a greyish or light brown colour, the latter being especially distinct in spirit pre[)arations. The difference between these two, however, is more appa- rent than real, consisting, as Paget suggests, rather in the mode of an angement 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 ilevelopment in different specimens, being in some large and wav\ , and in others very short, and often intermixed with cytoblasts 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 * Br. West has furnished some interesting sta- tistics upon this subject, (l.ectures on the Diseases of Women, Pt. i. p. 277. 1856.) j- For an account of these see Paget’s Surgical Pathology, Yol. II. Lect.Y. ; and also for those of the uterus. Bidder, in Walter ueber flrbrose Kdrper der Gebarmutter. Y Y 6&0 UTERUS AND ITS APPENDAGES. mass, so tliat a muscular rather than a fibrous it may fie easily detaclied and turned out of tissue residts. A small quantity of elastic its investing capsule {fg. 475 ). fifire is also occasionally found in these ute- rine formations. Fig. 475. Fig. 474. 'J’lie structural variations ofiservafile in fifiroid of the uterus, are de[)endent 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 111 size from a [lea 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, ai'e apparently nearly bloodless ; at least, injections cannot be matle to penetrate them. The different configurations which these masses of uterine fibroiil assume, appear to depend in a great measure upon accidental conditions. In this particular three varieties may be noticed. Irf 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 ttterus, but more commonly there exists a distinct boundary formed by loose cellular tissue with which the- tumour is so lightly connected that 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. Snbperilotiecil fibroid. — In this variety the fibroid mass or masses protrude i 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 i they remain attached to it by a peduncle. ' These masses consist entirely of fibroiil, having either simply an investment of perito- j 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 | ca()sule composed of the natural tissues of the ' uterusis formed arouml the tumour (y?g. 476.). 5 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 covei'ed 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 I polypi of the uterus. ' A ilistinction 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 ti>sue. The original position of the fibroid grow'tli 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- 691 UTERUS — (Abnormai, 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 fundus, 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 growth 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- ti.mes to tiiat 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 fig. 476. These sometimes appear to grow at the ex- pense of the whole uterine substance, so that the original organ is with difficulty discovered among the hypertrophied mass. Fig. 476. The uterus surrounded hy outgrowths of fibroid which have pushed the peritoneum before them, several having become pedunculated. (^Ad Nat. ) 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- 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 htEmorrhage, 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- blisheil, 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, w'hich 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 coin- |)osed 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 fibrinous or blood pol jpi. 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 fig. 477., is precisely that of the proper muscular coat of the uterus. Y Y 2 692 UTERUS AND ITS APPENDAGES. Fig. -177. Seclioii of a pnhjpus formed of the miiscidar tissue of the uterus. (After tVedl.) The fibres, arranged in bundles, run in diHerent directions. At u «, they hav'e been divided trans- versely, and in other parts obliquely. Conqiare with fuj. 4oti. The malignant polypi, and those which are funned of hypertrophied miicoiis structure, belong to another category, and will be de- scribed hereafter. 4. Pathological conditions of the mucous coat. — a. First uniler this head ma3' be noticed simple hyperlrophi/ of the uterine mucous membrane, followed often by a partial shed- ding of that structure in the form of the so- called Dysmenorrhoeal membrane. — Tlie term men- strual decidua wotild probably form a more appro|>riate 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 onli- nary condition *, except in the one particular, that it hiis undergone a certain degree of hypertrophy. (Ftg. 443.) Tlie hypertrophies which the mucous membrane of the titerus undergoes in various circumstances form a most interesting subject for study, but all of them are not pathological. The most familiar exanqile of normal hypertro|)hy 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 exjtands, ami its tissues become opened up by' an in- creased flow of blood, and a consequent rapiti 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 tho.se cases where the ovum never enters the uterus at all, but is developed externally to that cavity (extra-uterine gesta tion ). Flere a most perfect tiecidua is usually found lining the uterus. The exceptions are few in which the uterine mucous membrane, uniler these circumstances, does not exhibit any increase of thickness, but retains or nearly so, its ordinary' characters * See on the structure of the uterine mucous membrane, p. 636. 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 occiqried by one of these tumours, exhibits a delicate decidual lining. The deciilual membranes occasionally cast off from the uterus under circumstances of ilysmenori hcea, 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 ue- 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. j b. Hypertrophy of the follicidar .structures of the uterine mucous membrane. Follicular polt/pi. AIucous polypi. Cysts. — The patho- ' logical formations which take their origin in ' the mucous membrane lining the uterus, con- sist chiefly in hypertro[)hic growths of that membrane, and of its follicular structures. They pre.sent usually two varieties, according ^ as the follicular or the ordinary mucous tissue j 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 Fallofiian 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 |j and covered by a layer of epithelium, beneath which is a thin extension of the uterine mu- cous membrane. This is often sufficiently .'j 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. i Between these elongated follicles there ts a tu 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 C93 UTERUS — (Abnormal Anatomv). of that structure, including a variable propor- tion of the subl\ing 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. Pedunculated pnli/pus 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 {)a[>illary 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. Internall}' 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 reacb. 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 tbe cervical folds, or protrud- ing from the os uteri. These consist almost exclusively of distended Nabothian follicles. c. Hypertrophy of the filiform papiUce of the cervi.r. — A variety in the coiulition of the filiform pa|)illrE upon the vaginal portion of the cervix has been described at p. 6.39. These papillae, nstead of being short, and covered by pavement epithelium up to the very margin of the os utei i, as they are upon the rest of the cervical lips, may present the same condition which they have within the cervix, w here they are longer and larger, and are not bound dow n by a continuous lay er of covering epithelium. These papillae often appear at tbe margin of tbe 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 pa|)illas, that the hypertrophied I’ollicular structures, form- ing the cysts and polypi recently described, bear to the cervical follicles in a iiealthy con- dition. Both the hypertrophied and the na- tural papillte 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 iiiflammntory 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 tincse. This affection is usually com- bined with a corresponding hypertrophy of the projier 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. anil 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 cry pts, 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 C40. Y Y 3 694- UTERUS AND ITS APPENDAGES. the natural boundary between tiio lower edges of tlie cervical canal and the lips of tlie os tincaj being now transferretl 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 he observed upon only one lip, or upon both simultaneously. It re- quires special notice here, not so mucli 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 inflammalmn of the mucous coat. Endo-metritis. JMetritis calarrhalis. Me- trorrheea. Catarrhus uteri. Acute and chronic catarrh. Lcucorrhea. Fluor alhus. Tlie ordinary inflammatory affections of the uterine mucous membrane in the iinini|)reg- 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 hyperasniic 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 [>arts. In congestion of the mucous membrane lining the body of the uterus, the superficial capillaries, whose healthy forms are represented in Jigs. 4.39 a and h, 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-purnlent 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 betw'een 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. II. Hennet. 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, anil 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 papillai 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 mateiially 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, envelo[)ing 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 jiroducts 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 J affections. Ulceration of the mucous coat. MetroAiel- i cosis. Granular tdeer. Simple erosion, abra- sion and e.vcorintion. — These terms have been severally employed to designate certain con- ilitions 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’. il * This point, under both these condition.®, ' is illustrated with great fidelity in the coloured de-' lineations of Boiviu and Dughs. 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. Tj-ler Smith, in Vol. XXXV. of the Med. Chir. Trans. 695 UTERUS — (Abnorbial Anatoma’). 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- matorv 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 fidfil 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 may 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 ; and hypertrophic 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 ( Jig. +24.), and after running down to the very margin of the os tincae terminate there in a narrow bor- der, or tuft of filiform papillte, 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. Beunet, loc. cit. p. 79. miniature wheat-sheaves heaped together. Each papilla is perfectly free and possesses its own proper epithelial coat.* This little grou|), 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. Tliese papillte 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 jmrts 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 fi-om 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 aphthre 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 wdien 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. A' A' 4 (i9G UTERUS AND ITS APPENDAGES. enliiigeil muciparous follicles*, which in three different conditions or stages correspond with three varieties of psetulo- ulcers of the aph- thous kind. In the fir.st variet}' the follicles are closed ami pi'pject like millet seeds above the general level of the cervix. They contain a little glairy Huid, aiul may he compared to the distended closed follicles described at [). 640., as occurring within the cervical and uterine cavities. They are almost always |)laced at such regular intervals apart, that they must be regardeil as natural structures enlarged, rather than as pathological new for- mations. The second variety consists not of closed but o[)en follicles similarly arranged. Within and at the bottom of many of these may be seen the filiform [lapillae enclosetl, cup-like, and resembling the stamens in a half opened flower. Similar follicles to these occur some- times within the ccrvi.x under ordinary circum- stances. When these papillte become hypertrophied and sprout otit above the cup-like level of the containing follicles they form Horitl-looking ami elevated spots resembling granulations in ap[)earance, 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 tbe s|)ecultun during life exhibit appearances that are regartled by many ob- servers in the |)rescnt 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 regiirded 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 vjew, and also for the purpose of avoiding the confusion which from the time of Hunter downwards has at- tended the emjjloyment of various terms for the designation of ulcerative [>rocesses, of those at least by which the particles of open or exposed surfaces are removed, it may be w'ell to adojit some such distinction as that proposed by Mr. Paget, namely, to regard as abrasions or excoriations those conditions in which the epithelium or epiilermis of an in- flamed part is alone removed, and those only as ulcerations in which the removal extends lurther to the vascular or proper tissues be- neath the epidermis. J Judgetl by this test, there may be excluded, first, all those apparent sores which, begin- * See p. (!40. t Excellent re]ireseiitations of the varieties de- scribed above will be found in Boivin and Dugfes’ Atlas, pi. 25. 27. and 33,, and in Pichard, Blal. des Femmes, ]il. 3. I Surgical Pathology, vol, i. p. 119. ning invariably from within the margins of the os, and a[)[)earing 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- tlitions commonly assigned to ulcers of the uterine neck. These, almost without excep- tion, consist of the inflammatory conditions already ilescribed as hy[)ertrophies 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 noi-mal boundary of the os, or line of demarcation between the vaginal and cervical mucous membrane, now disturbed ami thrown out of its natural place. The granulations u|)on 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. The.se conditions of the uterine cervix in res[)ect 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 hypertro[)hies 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” afipears to be a more appropri- ate designation and [treferable 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 covei ing 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 (he 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. 697 UTERUS — (Abxorjiai, 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 tliis struc- ture. But it is deserving of consideration that the papillx- 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 of 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 w hich often accompany faulty states of ihe 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 [iroduces 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, liilfilling the conditions that would entitle them to be admitted into the category of true ulcerations. Dis/evsions of the uterine cavity, by liquid or gaseous contents, constitute the affections termed respectively hydrornetra, hcematometra, 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 atroph}- of the uterine walls. * Some of these morphological varieties have been described in a preceding page ; and sucb, 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. Hydrornetra 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 visens, 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. -j- The fluid which accumulates in such cases may be thin and watery, but it is more often pijriform, and in some instances, as in Dr. Hoofjer’s ex- ample, which resulted from the opening of an abscess into the uterine cavity, it consists of |)ure pus. To these cases, the term pyo-metra would be perha])S more appropriate. Collec- tions of these kinds amount usually to several ounces, or may reach one or tyvo 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 hydrornetra, 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 vetulurum of Mayer. Hydrornetra is to be distinguished from hydrorrhcea 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 h) men 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 fluirl, 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. t Hooper, Morbid Anat. of Uterii-S, pi. III. j Case. l)r. A. T. Thomson, iled. Chir. Trans, vol. xiii. 698 UTERUS AND ITS APPENDAGES. ings in tlie uterine wails ; or, if previous ad- hesions are formed, tlie finid may escape by the vagina or rectum. HoL'inatometra may occur also in certain malformations of the uterus, as already described (p. 680.). Physometra. Pneumatosis s. tympanites uteri. — This affection, known to Hip[)ocrates* * * § 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 accom|)anied 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 ]mtrida), 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 |iresence 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. fiS-i., but this is so rare an affection of the uterus that no anatomical collection, I believe, in this city contains an example of it. Rokitansky’s often-quoted casej 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 18-JO, 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 inferreil 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 acconqianied or [)ieceded 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 un(]uestionable evidence of a prior act of impregnation. Connected with these, when the degeneration is not much ailvanced, may be sometimes found an embryo per- * De Morbis Mulierinn. t Re Causis et Signis Morb. Diuturn. j Loc. cit. vol. ii. p. 291. § For descriptions and illustrations of these struc- tures see Wed 1, Pathological Histology (Syd. Soc.), p. 172. 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 |)arts. Obliteration of the external os uteri, either partial or complete, is the most common of j 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 entirely 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 atresise 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 oidy 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- i cesses by which the structure of the uterus is || metamorphosed or disintegrated and ultimatelv II 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 [irincipal varieties of enceph;i' 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 I 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. 699 UTERUS — (Abnormal Anatoafy). 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 traceil. 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 scra()ing, 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 irregidar funnel-shaped cavity, bounded below by hard rugged margins. Or fungous vascular growths, friable and easily bleeding, sprout fiom the part and entirely destroy its natural configuration. A yellow or greenish-brown sanious discharge, of a highly fetid odour, mixed occasionally with 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 puti efied 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 idcera- tion, while the fundus 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 {Jig. 'f79.). If life is Fig. 479. Cancer of the neck of the uterus (a), extending to tlie bladder {(>), rectum (r), and upper part of the vagina (u). {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 lay open the peritoneal cavity itself. The penetration of the bladder earlier than the rectum, which almost uniformly obtains, is explained by the ditferent modes of connexion of the cervix with these two parts. Since nothing but fibrous tissue intervenes between the bladder and the anterior cervical wall (Jig. 426. b b and 433 f j, 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 {Jig. 426. 433. g), the cancer mat- ter does not so easily penetrate tliroiigli this, not at least until adhesions have formed.* But cancer may commence in the fundus or body, instead of in tlie cervix, although this is rare ; or it mav extend to the utei us from the ovary. In this way extensive dis- organisation of the adjacent [tarts may occur, the cervix remaining intact. f Cancer, when thus developed, especially in the encephaloid variety, assumes often the form of distinct masses or tumours, rather than of an infiltration of the tissues. These tumours may be imbedded in the uterine walls, or form numerous irregular rounded and sometimes pedunculated masses, variously attached to, or projecting from their surface. On the other hand such a distinct mass formed in the substance of the uterine walls, or beneath the mucous membrane, may in the course of growth [lush the latter befoie it, and, subsetjuently acquiring a stem, may fill the uterine cavity or protrude into the vagina, and constitute a malignant polypus. In most cases of uterine cancer the uterus is the primary, and except in those instances where the disease has spread by direct ex- tension to adjacent parts, it may remain throughout the sole organ attacked. Or uterine cancer may be associated with like formations in tlie stomach, mamma, ovary, &c., and be develo[ied concurrently with or consecutively to these. Cancroid. Epithelial cancer. Cauliflower e.vcrcscence. — Cancroid of the uterus is li- mited in its commencement to tlie vaginal portion of the cervix, and [iresents the follow- ing [irincipal varieties. It may appear under the form of papillary growths, resembling con- dylomata, which spring from the mucous sur- face, and form little compact masses that gradually, by the growth and elongation of the [lapillae, become soft, [mlpy, and brittle, and easily bleed on being touched. After a time a basis of cancroid is developed in the cervical tissues, or the papillary growth appears upon a larger scale, forming a hard, knotty, and brittle mass, which grows with tolerable ra- [lidity, and ultimately more or less fills the vagina or protrudes from the vulva. In form the growth often resembles a cauliflower, to which it was likened by Dr. John Cllarke. The surface is of a bright flesh colour, and is covered with small projections or granules. These again are united into larger masses or lobes, set upon short and broad stems, that ultimately coalesce into a common basis formed by one or both lips of the cervix. The whole tumour has a certain firmness and solidity ; but the su[)erficial granules are so brittle that slight handling causes some to break away, a free haemoi rhage resulting. Or the cancroid, after being developed in and beneath the mucous membrane ol the cervix in the form of little granular masses, gradually * Ur. West is, T believe, the only author who has hitherto pointed out the true cause of this difference, f See case, p. 593. breaks through the surface ; while in the course of time ulcerations form upon the most prominent portions, and these coalescing, while increased deposits of cancroid take place in the sublying tissues, which in turn are also destroyed, a sore, more or less ex- tensive, is formed that in its further aspect and progress very nearly resembles encepha- loid cancer. Regarding the structure of these cancroid formations, they are, according to Virchow, at thecommencement simple papillary growths, and later assume the characters of cancroid. At first they apjtear in the form of small vil- lous [)iojections from the surface, composed of an outer very thick layer of peripheral epithelial plates, and an inner one of cylinder ephithelium, the interior of the villus consist- ing of large blood-vessels. These vessels are chiefly colossal thin- walled capillaries, which either form simple loops at the extremities of the villi between the layers of epithelium, or ramii'y in compound loops over the surface, or lastly, present a retiform arrangement. The great size, tenuity, and superficial posi- tion of these vessels ex[flains the profuse dis- * charge of watery fluid, and frequent bleedings, which constitute such striking features in the progress of the cauliflower excrescence, as ' W'ell as the entire collapse and almost total . disa[)|)earance of those tumours after death, so that only slight traces of them are found ' on post-mortem examination. ■ 5 At the commencement the papill® are --If 1 single and close-set, so that the surface, as ' (Jlarke desci ibes it, is merely granular. The i peculiar cauliflower form is occasioned by the branching of the papillm, which ultimatelyBI form fringes an inch in length. After thisEal superficial process of growth has continued Wl for a certain time, cancroid alveolar space-sSjal begin to be formed at the base, between thejBI fibrous and muscular layers of the organ. AtVI first these appear as simple spaces, withW I epithelial contents, but later are found alveoli,^ from whose parietes new papillae spring,')^ which also become ramified, constituting, arborescent proliferous growths. Corroding ulcer. — Here may be noticed anB| affection of the uterine cervix, whose exact^ pathological relations have not been deter^^l minetl with sufficient accuracy. The corrod-'*^' ing ulcer, first described by Dr. John Clarke,^ j and compared by Rokitansky to a phagede-^? nic (cancerous) sore of the skin, differs mainly from cancer in the absence of a cancer basis, or of cancerous infiltration of adjacent tissues, while it resembles the destructive march of cancer in its mode of gradually dis- ' integrating, and destroying the os and cervix,^] and even poi tions of the body of the uterus, and extending to the bladder, rectum, and ad- jacent structures. The characters of this ulcer are those of a ragged, irregular-margined sore, with a brownish or greyish base, from which issues a thick [jurulent or copious watery secretion. The margins and base may be thickenetl by inflammation, but there are no granulations. I UTERUS — (Abnormal Anatomy). 70i j - Upon tlie question of the nature of this I form of ulceration Foerster gives a useful hint. After describing a case which fell un- i | der his notice, and where he could find no I traces of either encephaloid or epithelial can- cer in the base of the ulcer, he mentions another which also to tlie naked eye ap- peared to have no cancerous basis, and yet on microscopic e.xamination the entire base I of the ulcer, to the depth of a line, was \ found to consist of cancer structure.* May I not the thinness of this layer, by limiting j the pabulum which feeds the progress of the ' ulcer, explain the slow advances of the latter ! observable in some cases of corroding ulcer ? Tubercle rarely etiects the uterus, and still )[ more rarely is it a primary disease of that : organ. 'I Tubercle of the uterus exhibits the follow- • 1 ing peculiarities. The tuberculous deposit is ij limited in the first instance to the mucous membrane of the body of the organ. Here I it occurs either in the form of tuberculous Ij granulations, isolated or collected in groups, i or more often as a uniform infiltration, limited at first to the mucous membrane, but ulti- t mately penetrating more or less deeply the It sublying uterine parenchyma, and accompa- i nied by hypertrophy of the muscular coat. ) In the subsequent metamorphosis of the tu- ^ bercular formation the infiltered membrane li softens and melts down, so that the cavity I becomes filled by a purulent pulpy fluid. The I tubercular infiltration terminates abruptly at ) the inner uterine orifice f ; or if rarely it k penetrates the cervical canal or appears upon I' the vaginal portion, it is then only in the I 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 comlition of fthe mucous membrane lining the Fallopian tubes. These latter are found distended and t their canals filled by caseous tuberculous i matter. < Solutions of Continuity. < Laceration of the walls of the uterus occurs if under various circumstances. It happens I rarely in the unimpregnated organ, more fre- i quently during pregnancy, and most commonly i during labour. I Rupture of the walls of the nnimpregnated ' j uterus can only occur under abnormal condi- 1 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 hmma- ' tometra. See p. 697. Rupture during pregnancy may happen at almost any period, but chiefly during the ' j latter half, although it may take place even as early as the second month, as from vo- miting.J Or it may be occasioned by violent * Handbueh der speciellen pathologischen Ana- tomic, 1854, p. 318. t Boivin and Dugbs’ Atlas, pi. xvi. j Case by Collineau. Journal Gen. de Mdd. 1808. spasmodic contraction, or from contusion or sudden concussion. It is most likely to happen in the case of the imperfectly de- velo[ied 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 reeordetl 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 ujtwards, 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 ap|)arently 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, {fig. 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' Ur. Merriinan. Synopsis of Difficult Parturition, 1826, p. 268. f 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 nipidly emptied, or under other circumstances vvhicli 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 relaxeil and undimiuished in size, or ;i 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 |)art or the vvhole 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 htemorrhage from the un- coutracted portions of the uterine walls. In explanation of these irregidar contrac- tions, it has been usually assumed that the contracted portions consist of the fibres that have retained their vigour, and the relaxeil 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 erroneous interjiretation of this phenomenon. It appears to depend rather upon arrested peristaltic action, which may indeed be, and |)robably 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 [)art 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 hemorrhage 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. — Tlie 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 w hich has been exposed by the separation of the [dacenta, 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 corre.sponding 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 r 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 arc 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 mors spongy, and redder than usual ; but in those forms of inflammatory action which rapidly pass into the puriform stage, the subjacent tissues become infiltrated and softened, so that they may be easily scraped away in the form 703 UTERUb — (Abnormal Anatomy). 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 w'alls, it may extend to the spermatic and hypogas- tric veins and their tributaries, either ui)on 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 [)lugs 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 fistula 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 lastl}' 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 UTERUS AND ITS APPENDAGES. TOi topical condition, which may be viewed as the local expression of the former. In a large niimitcr of instances, however, the affection of distant parts may be considered as the re- sult of a secondary blood infection, i. e. of a poisoning of the blood by the introduction of some products from the original nidus of dis- ease, and [)articiilarly of venous [lus 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 decitlua, the con- tents of the uterine cavity, consisting of va- rious puerperal products now exposed to the direct influence of the atmos])here, are brought into immetlitite relation with the patent ori- fice of the titerine veins terminating upon the placental sjiace. Through these a copious reception of the exndated 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 [tros- 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 [tarts and organs ; and of tleposits within the larger vessels, chiefly the veins leading from the uterus, or in the capdiaries of organs often far removed from the original seat of inflammation. Ihe effusions upon the jteritoneum 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 * Eokitansky, np, cit. vol. ii. of the intestines, w hich are later tiffected than the serous structures, a less sthenic form of exiulation is usually found, the effusion con- sisting here of sei'ous, gelatinous, or purulent extulations (the former contributing largely to the [jroduction of puerperal diarrhoea), and of infiltrations into the mucous and sub- mucous areolar tissues. These various exudative [trocesses, whose [ireference for particular tissues is probably in jiart 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 [uoducts bear exact relation to the nature of the previous infection, and of the dyscrasis arising out of it. The character aud modo 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 [iroduced 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 [jroducing the lobular infarctions, and in more advanced inflammatory stages, the so-called metastatic abscesses and sloughs of various organs and tissues. The obstruction to tee 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 conilitions of coagulation, forming long cylindrical plugs, as in crural phlebitis, or shorter clots, whose red coloration de[)ends upon the degree in w’hich the blood corpuscles may have been incorporated in its several laminte, or their, paler yellow colour, iqion the absence of the same, and the consequent greater purity of < J 705 UTERUS — (Ligaments of). tlie (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 vtero-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. Tims a vertical septum is formed, which divides the cavity of the pelvis transversely into two chanibers ; 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 40-i.y’. , 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 laminte 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 alminas together. This structure should be regard.ed 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 o the spine; while the interspace of the folds fuffices for the conveyance of vessels and lerves. The resemblance to a mesentery is note obvious in the bicorned and intestiniform ■’.terus of the mammalia generally, as well as Supp. of many other vertebrata in which it forms the mesomeirium. The utero-sacral ligameiits.- — 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 tw'O 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 ntero-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 tw'o slighter lateral folds, containing bundles of fibrous tissue. These constitute the anterior or utero-vesical ligaments. The round or sub-pubic ligament: Ugamen- tum I'otundum, Ugamentum uteri fcrc«. — 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 su|)erior 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 JMr. 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 Giin- 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 thelowerborderof the internal oblique and transversalis muscles, from which it is separated by a thin layer of fascia continuous with the fascia transversalis : it then gets betw’een the layers of peritoneum forming the broad ligament, along which it ]jasses backwards, downwards, and inwards to the point of insertion already described. ♦ On the Structure and Use of the Ligamentum Kotundum Uteri, Phil. Trans, p. 515. pt. if. 1850. z z 706 UTERUS AND ITS APPENDAGES. 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, lyni[)hatics 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 ineuinal canal, where it forms the canal of Nuclc. 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 previ nt, 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. Spn. Vulvo-uterme canal. — The vagina con- stitutes a flattened cylindroid, extemling from the vulvar orifice to the neck of the uterus. It lies entirely within the pelvis, between the blailder 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 u[)per 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, init apuears as if it were let into its upper wall (/g. 433.). IJiinensions. — 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 follow'ing 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 bv 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 1 . 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 muciparous follicles. Internal surface. — Upon the inner surface of the canal the mucous membrane is throw,! into folds, which, iu 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 columnae rvgarum, 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 ;i fimbriae of the Fallopian tube, es()ecially 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 uterme artery. These descend between the bladder and the vagina, supplying branches to both those parts. An abundant and intricate net- work is formed iu the vaginal walls by the ramifications of the smaller vessels denvedj from these sources, which interpenetrate the several coats down to the mucous membrane.' Vems. — 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 hulb, unite to form a considerable plexus, especially around the vulvar orifice termed the vaginal plexus. From this plexus branches pass to 707 VAGINA — (Abnormal Anatomy). the vesical, and hemorrhoidal, and uterine plexuses ; the blood being finally collected by large veins which empty themselves into the internal iliacs. Figs. 482. and 483. The hympatics 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 [)osi- 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 feetus 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 (/tg. 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 ini()erforate, 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 I'rom 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 Insemination, p. 671. t These cases are sometimes recorded as examples of imperforate hymen. 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 withiii that cavity. Prolapsus of the vagina occurs sometimes alone, but it is more often com- bined with procidentia or inversion of the uterus (fig. 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. (2^fg.468.) 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. Sohitions of continuity. — Laceration of the vaginal walls may occur during obstructed la- bour, and is then frequently associated w'ith 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 cloacce 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 (goiwrrhaea). In the more acute form the mucous membrane is highly vascular, and is sometimes excoiiated, from excessive shed- ding of epithelium. The discharge [>resents variable characters, from the viscid yellow puriform mucus, to the creamy, milk-hke, or thin, nearly watery, fluid (leucorrhaa^. Croupous exudations occasionally form upon the vaginal raucous membrane, chiefly in con- nexion with typhoid exanthematous or puer- peral processes. Epithelial desquamation. — 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- seepuent narrowing of the canal. In this state * I 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 thejyhave been confounded with the true dysnienor- rhceal membranes which consist of the lining mem- brane of the uterus. See fig. 443. z z 2 708 UTERUS AND ITS APPENDAGES. tlie vaginal walls are easily lacerable, or if snbjectetl to continued pressure pass readily into gangrene. Abscess forms occasionally in the vaginal walls, but many of the ab.scesses 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 u.sually either syjihilitic or cancerous. Gani’reue of the vagina occurs in conjunc- tion with gangrene of the vulva in septic [)uer- peral processes ; or it results from pressure in protracted labour. Spontaneous gangrene occurs also occasionally in infants and young children. Cysts and tumows. — The former, if of small size, mav 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 vvay, fibrous or osseous tumours growing from the perios- teum or ligaments of the [lelvis, ovarian, or even uterine tumours may, by pushing before them the walls of the v.igina, 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 ap|)cars most commonly as medullary can- cer, taking the form of tuberculated masses or ridges, which narrow or obstruct the passage, and cpiickly 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 fistulas 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. SvN. Vvlva. Pudendum. — These parts per- form subordinate offices in the act of repro- iluction. 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, whicli 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 exce[)tion 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. TiiE 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. 'I'he latter contains many sebaceous and hair follicles. The hair is not developed until the age of puberty. Fig. 480. K.rternal organs of generation, and commencement oj vagina. {After Huguier.') t, labium of left siile (that of the right side is divided and partly removed to expose the vagina and vulvo-vaginai gland); n, nympha ; c, gl.ms ditoridis; pc, preputium ditoridis; a, vestibule; «, orifice of urethra; va, vagina; g, vulvo-vagiiial gland, or gland of Bartholin and Duvernay; d, duet of the same. The Labia, termed also labia majora, to distinguish them from the lesser labia or nymphae, are two symmetrical tegumental folds(/g. 480. //), placed one on either side of the rima or fissure which leads to the vagina. The labia vary considerably in size and forni 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. 7(0 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 nuicous 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 uniteil above by a sliglit frenulum, 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 tlie former, just below the entrance of the vagina. The transverse boat- shaped furrow between these constitutes the fossa navicularis. 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 sejiarate. The normal descent of the testis into the scrotum in the male, about the seventh month of intra-uterine life, is rejtresented 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, nymphte, and vaginal orifice are brought into view. The Cutoris (figs. 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) (fig. 480. /ic), 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 sensitive mucous membrane, which is abundantly supplied with nerves ; this terminates the free extremity of the organ : a body (fig. 481. A), 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 jside. 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 chlorides'), composed of striped muscular fibre, are in- serted into the crura. They have the same relations, and, according to Kobelt, are I'ully as long as in the male (fig. 483. n). Blood-vessels. — Tw’o dorsal arteries ( fig. 481. l>), 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 f g, veins of deeper origin. These transmit the blood to the vena dorsalis ; h, dorsal artery; iii, dorsal nerves: h, the venous plexus, termed pars intermedia (shown also at d. Jig. 482., and e, Jig. 483.) ; 1, communicating venous branch between the glans clitoridis and pars inter- media ; Hi, ascending venous canals proceeding from the pars intermedia (li) to the under surface of the body of the clitoris; 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 ; g, 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 tnma dorsalis, d. From the cavernous bodies the blood is also collected by a series of vascular canals, of which an account wdll be presently given. Nerves. — The clitoris is richly endow'cd with nerves, i i, which arc relatii ely 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 ap[)arent. In the male, the groove along the under surface of the penis is closed in, and at the same time the ra|ihe of the scrotum is formetl ; while in the female, the parts corresponding with the bulb and corpus spongiosum urethree 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 develo])ed independently of them. NviMPiiai. — Labia minora v. interna. — These consist of two thin and slightly fleshy folds of mucous membrane {fig. +80. n), soinewhat 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 nymphm commence above by two roots. The inner one, thin and membranous, is inserted beneath the glans clitoridis, and forms with its fellow a kind o'l 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 w'ith 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 urethral 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 unfoliling 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 nyinpliEB correspond with that part in the male which forms the tegumental covering of the urethra, but which remains ununited in the female along the median line. The Vestiuui.e. — This term has been employed in two senses. In its widest sense it includes all the [larts which immediately sur- round the vaginal orifice. In a more restricted meaning, it is limited to that triangular patch of mucous membrane {fig. +80. 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 meatns urinarius, which forms here a slight prominence {fig. +80. 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 nympha;, 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 I’nrther narrowed by a fold of the vaginal mu- cous niemhrane, the hpmen, 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 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 valvula; ; 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 fcetiis 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 verlical slit-like orifice, the direction , of which is apparently due to the lateral com- j |)ression 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 I 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 other 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 vei tical. * Such is the condition of the hymen during J foetal and infantile life. But as growtlU| advances the posterior half becomes much j more developed than the anterior, just as J 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 semilunar fold, the concave border of which EXTERNAL ORGANS OF GENERATION. 711 is directed upwards or forwards, while that which had been in the foetus, the upper half, has now become unfolded or lost among the jdaits 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 t3pical form of the hymen. But the foetal form is also often re- tained, namely, the circular fold of mucous membrane, which, as the jjarts 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- fuselj' 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 foetus. The hymen with a central or nearly central circu- lar orifice, results from a flattening down and retiring within the vaginal orifice of the cone ; the retiring naturally following uj)on an expan- sion of the vaginal walls as growth advances. 'I'he 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- fan9'. The hymen, however various its forms may he, consists of a double layer of raucous 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, y et 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 little fleshy bodies occasionally observed near the orifice of the vagina, termed carunculce myrt formes, 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 v/ith the hymen. The hymen 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 ammouiacal 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 (vestibular follicles, fg. 480. v~), around and upon the sides of the vneatus urinareus {urethral follicles, fg. 480. u ), and at the sides of the entrance of the vagina (lateral follicles of the vaginal orifice, fig. 480. vaf The muciparous follicles are composed of a delicate vascular mucous membrane ai'ranged 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' y-ears of age, who had previously been a prostitute, a tough membranous circular hynnen 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 ill a cnl-dc-sac. Tlie 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 vulvo-vaninal 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 redilish 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, anil their outer surface in relation with the con- strictor muscle of the vagina. The lobules composing this gland send otf 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 nymphas 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. Uniler 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 infimcy and early life it is very small, attaining its full develop- ment in the adult, anti again diminishing and even disappearing in old age. When the labia and nymphie arc abscised a series of vascular erectile structures are brought into view, which, together with a special muscle, surround the vaginal orifice. These are the vestihidar bulb, pars intermedia, and constrictor vaginee muscle. Pars intermedia. — From the dorsal vein of the clitoris {Jig. 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 cliloris in the form of a frill that completely occupies the angle contained in the curvature of the organ (Jig. 481. m and 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 urethrae and the corpora caver- nosa penis. After receiving branches from the glans clitoridis (Jig. 481. 1), ny mphae (r), and labia (p), they form on either side a series of convoluted veins (/r), which spread- ing downwards and outwards ultimately termi- nate below in the bulb of the vestibule (Jig. 482. and 483. a). This is the structure termed by Kobelt the pars intermedia. It corresponds with the coiqnis spongiosum ure- thrae of the male, which in the female remains divided into twm halves. The arteries of this APPENDAGES. Fig. 482. structures connected with it. {After Kobelt.) \ a, vestibular bulb of the left side ; 6, 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 I 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 ; y and i, lateral communicating i branches between the vena dorsalis clitoridis and I pars intermedia; h, vena dorsalis; h, bend of the |l clitoris ; /, crus clitoridis ; n, vulvo-vaginal gland. , structure {fig. 481. ping down sud- denly, and ])assing 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 latei'al. Lastly, when the vessels of the cord divide before arriving at the surface, they form x\\e 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, so.fi, 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 lahour 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 hy which the uterine arteries (fg. 484. a a) and veins pass fiom 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 oft’ 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 foetal 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 spoiiizy sub- stance, which is made up principally of count- less ramifications of the fcetal villi. These are attached at their base to the chorion, from 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 tin, 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 rf/j, decidual prolongations ■which form the dissepiments dividing the placenta into lobes funis ; am, amnion; ch, chorion; vf, fetal blood-vessels (divided) upon the surface of the placenta; vv, villi; us, uterine sinuses; aa, 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 fcetal surface of the placenta, are numerous slieet-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 — V" 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 vilU. — 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 loot 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 oft; 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 ilistinct 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 [)ulpy 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. 4Sfi. h). 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, i'orining generally a single layer. In the apex of a grovving tuft, or forming a distinct bud projecting from its extremity, may be often observed a group of similar cells which a[)pear to be passing off from a spot in the centre of the mass.* These cells perform important parts in the growth :md offices of the villi, which will be presently noticed. The internal portion {fig. 485. h) consists of a soft and [Hilpy structure which envelopes the blood-vessels of the villi. In its substance also are embediled numerous cells of a similar nature to those observed iu the structure- less sheath. Termination of the fcetal 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 ilivide 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 pul|iy 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, 1815. Fig. 485. a, terminal villus of a foetal tuft, from a placenta of six months. The arteries, veins, ami capillaries are minutely injected. The latter, w'hich 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, immediate!}' 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 Nut.) 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 foetus 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 iu 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 foetal 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 Schroeder van der Kolk, who, in his recent W'ork, has described and figured them in a placenta of three months. Scanzoni also (Lehrbuch der Geburtshilfe,_/7^. 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. 719 PLACENTA — (Development). 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 {Jig. 484. d p'), which divide its substance into separate lobes. Upon thefloor also of the placenta all round the margin, where the decidua turns dowmwards and inward.s 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. Tei'inination 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 tne 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 abov'e described, be- come supei-ficially 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 w'hich 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 ckih-like villi of equal size. The extremities of these villi are sinipl}’ 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. Festal 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 b) 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 w ithin 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 V tliat which is derived from tlie ch.orion, im- portant modifications occur in tlie intei'ior structures. Up to a certain period of gesta- tion, the choi'ion and its villi contain no blood-vessels. According to the author last (pioted, blood-vessels first appear in these parts when the allantois reaches and ap[)lies 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 ceco- 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 Schroeder 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 Jig'. 485. Before the end of ges- tation, however, the greater part or all of these fine capillaries have ilisappeared, 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 fcetal portion of the pla- centa. The changes occurring in the maternal portion, or that which is suftplied by the de- cidua, are not less remarkable. Maternal portion. — Four princijtal 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. 480.). This is the condition of the ovum in the early part of the fir.st month of gestation. The second stage is marked by the com- mencing attachment of the villi ail 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, * Loo. cit pi. i.jig. 1. t For an account of the formation of tlie foetal chamber, and of the early steps in the construction of that portion of the placenta which belongs to the decidua, see p. 653. APPENDAGES. Fig. 486. Decidua at the beginning of gestation, exhibiting the fcetal chamber in the first stage of its formation. The ovum, being at this time unattached, has dropped out of it. {After IF. 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, a nis quae respirationi et nutritioni foetus mammalium inserviunt. 1837. E. H Weher, in Ilildebrandl’s Anatomic, b. iv., and in Wagner, Elements of Phy- siology. 1841. J Beid, Edinb. Med. and Surg. Journ., No. 146. J. Balrymple, Meilico-Chirurgical Trans., vol. xxv. 1842. Gondsir. J. and E., Anatom, and Pathol. Observs. 1845. Schroeder van der Kolh, Waarnemingen over bet Maaksel van de Mensche- lijke Placenta, en over haren Bloods-omloop. 1851. PLACENTA 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, whicli ap- portion the entire organ into separate placen- tulsB, 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. I'he profuse development of fine capillaries within the foetal 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 n)ore 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 illastrations of this article marked, “ ad na- turam,” are from original drawings and preparations in the possession of the autlior. 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 -(Functions). 723 subjects, as well as to the books quoted in the foot notes of this article. UTERUS AND ITS APPENDAGES. OV^ARY. yofmal anaioniy. 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. Funciions of the Ovary. the developmental changes in the ovicapsules, and the process of emission of ova, 552. 1st stage, origin of the ovicapsules, .5*54. 2nd stage, growth, maturation, and prepara- tion for dehiscence, 5.55. 3rd stage, rupture or dehiscence, and escape of ova, .5.58. 4th stage, decline and obliteration of the ovi- capsules. 561. A. without impregnation, 561, B. alter 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, 671. Abnorn.al Anatomy of the Ovary. effects of fXtirpating the ovary, 573. deficiency and arrest of development, 573, atrophy and hypertrophy, 573, displacement, hernia, 573. diseases of the tunics, inflammation, 574. ulceration, rupture, 674. hypertrophy, calcification, 574. diseases oi the proper tissues, hyper.Tmia, 576. inflammaiion, 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 j fat; hair; teeth; true bone, 584. origin of the so'id 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, 6i 0. external orifice, 600. pavilion or infundibulum, 601. fimbria. 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 tlie ovum undergoes in the tube, 609. Development of the Fallopian Tube. formation of the oviduct out of the duct of Milller, 613. 3 A 2 724. UTERUS AND ITS APPENDAGES. FALI>OPIAN TUBE {c07itinued). Abnormal Anatomy of the Fallopian Tube. defect and imperfect development, 611. peculiarities of construction, 615. displacements, 616. obliteration of tlie canal, 617. hyperaemla ; 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, 620. UTERUS. Normal Anato^ny. situation and position, 623. form, 624. dimensions and weight, 624. regional divisions ; fundus; body; cervix, 621. external surface, 626, internal surface, and cavities of the body and cer- vix, 626. 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 ; composition, 635, utricular glands or follicles, 636. structure and arrangement of the tissues composing the cervix uteri, 638. muscular coat, 638. mucous co.it ; epithelium, 6.38. papillte, 639. mucous follicles, 640. blood-vessels of the uterus, 640. lymphatics, 641. nerves, 611 . 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. 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, 649. the peritoneum, Cf9. the muscular coat, 649. the blood-vessels, 651. nerves the question of enlargement of the uterine nerves during pregnancy, 65 1 . mucous or lining membrane of the uterus; development into the decidua ; decidua vera and reflexa, 652. histology of the decidua, 6-57. 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. Functions of the Uterus. a. the office of the uterus in menstruation, 662. 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 nnmixed menstriud fluid; analysis, 664. source of the menstrual flux, 665. the means by which the blood escapes during healthy menstruation, GG5. 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. h. 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, 672. the peristaltic action of the uterus, and its cause, 673. the rythmic action of the uterus, and its cause, 674. influence of the different nervous centres upon the uterus in parturition, 675. the exciting cause of labour, 767, UTERI^S {ccnihiued').' Abnormal Aiiatomy of the Uterus. defective development, 678. 1st class, congenital defects, 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 four groups: group I. uterus bipartitus, 678. group II. uterus unicornis, 679. group 111. 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, 68 1. 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-peritouitis, 687. 2. pathological conditions of the subperitoneal fibrous tissue ; 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,” 689. 4. pathological conditions of the mucous coal, 692. 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 papilla 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; leucorrhoea, 694. 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 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 glass contraction (arre ted peristaltic action), 702. incomplete and retarded involution, 702. puerperal inflammation, endo-metritis, 7o2. metro-phlebitis, 703. metro-peritomtis, 703. blood dyscrases, 704. LIGAMENTS OF THE UTERUS. Normal Anatomy. the broad ligament, 705. the utero-sacral 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). composition, 706. internal surface, 706. arteries; veins; lymphatics; nerves, 707. uses of the vagina, 707. Abnormal Anatomy. anomalies of form and size, 707. displacements, 707. solutions of continuity, 707. inflammation, 707. epithelial desquamation, 707. serous and sanguineous infiltration, 707. abscess ; ulceration ; gangrene, 708. cysts and tumours, 708. cancer, 708. 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 vaginte, 712. EXTERNAL ORGANS (continued). blood-vessels and nerves of the external organs, 713. Abnormal Anatomy. labia, 714. clitoris, 714. nymphae and vestibule, 714. hymen and ostium vaginai, 715. PLACENTA. Normal Anatomy. form, 715. dimensions and weight, 715. foetal surface ; amnion ; chorion ; foetal blood- vessels, 715. uterine surface, 716. circumference, 716. substance, 717. tufts and villi, 717. terminations of the foetal vessels, 718. decidua, 718. terminations of the maternal vessels, 710. Development of the Placenta. of the foetal portion, 719. of the maternal portion, 720. Functions of the placenta^ 721. {^Arthur Farrc.') ANALYTICAL INDEX TO THE SUPPLEMENTARY VOLUME. ANALYTICAL INDEX TO TnE SUPPLEMENTARY VOLUME. Ovum (in Animal Anatomy and Physiology), 1 . (See also GcneraHoiC). I. of the ovum in general as related to the sexual process of generation, 3, delinition, 3. ovulation, 3. the chorion, 3. tl»e spermatic substance or sperm, 3. the embryo-cell, 4. development, or embryo-genesis, 4. structural distinctive characters of an ovum, 5. II. of tlie non-sexual mode of generation, 5. 1. of the process of reproduction in 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, 15. Acalephas, 20. Mollusca, 22. Salpidas, 23. Entozoa, 24. Cystic Entozoa, 25. free tapeworms, 27. Trematoda, 29. Annelida, 32. Insecta: Aphides. 33. general remarks on alternate generations, 13. 31. the “ nurse” of Steenstrup, 37. parthenogenesis, 37. additional remarks, 4". of the ovum previous to the commencement of fcotal 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, 4G. first group, 46. second group, 46. third group, 47. § 2. further comparison of the ova of animals 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 Fi.shes, 50. in the Frog, 61. 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. h. structure of the ovaries ihemselves, as related to the production of ovula, 56. Supp. Ovuniy 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 chalazse (grandines), 64. formation of the external or accessory parts of the bird’s egg, 65. ovarian ovum of birds ; ovulura ; yolk and its contents, 68, microscopic structure of the ovum, 71. early condition and tirst formation of the ovarian ovum in birds, 74. morphology of tiie bAd'a egg, as ascer- tained from its first origin and develop- ment, 75. § 5. more detailed description of ova belonging to secoiLd 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, [82]. 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]. formation of the cumulus, [90], similarity of the structure of the ovum throughout the families of the class Mammalia, [90], except in the Monotremata, [90], ova of the Ornithorhynchus, [9J]. ova of Echidna hystrix. [91]. third group of the ova of Vertebrate Animal.s, [91]. Amphibia — Batrachia, [01], structure ol the ripe ovarian ovum in Amphibia ['.*2]. germinal vesicle [93], yolk-substance. [93]. formation of the ovum, and changes in its progress, [94]. Osseous Fishes, [98]. II. Invertebrate Animals, [104]. large-voked ova with partial cleavage, [105]. Cephalopoda, [105]. Gasteropoda, [105]. Acephal.i, [108J, Arthropoda. [1 10]. Insecta, [1 10], Arachnida, [114], Crustacea, [1153- Aniiulata, [i 17]. hotifera, [118], Tnrbellaria, [119]. Entozoa, [120], Nematoidea, [120]. Trematoda, [124]. Cestoidea, [124]. Echinodermata, [125]. B 730 ANALYTICAL INDEX Ovum, Invertebrate Animals Polypina, [12G], Acalephre, [12t<]. Protozoa, [129]. Porlfera, [129]. Recapitulation and conclusion, [130]. 1. definition of the ovum, as related to its own structure, and its history in connection with the reproduction of the species, [130]. 2. recapitulation of the most general facts ascer- tained by the comparison of tlie ova of different animals, [132]. 3. morphology of the ovum : homology of its ]>arts, and relation of the ovum to other organic structures, [134]. 4. phenomena attendant on maturation of the ovum, and its discliarge from the ovary, [136]. 5. relation of the ovum to fecundation by the male sperm, [130]. 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 i fthe ova of animals, [141]. the albumen or white, [Ml], vitelline, [141]. ichthine, [141]. ichthidine, [l U]. ichthuiiiie, [MIJ. Pancreas, 81 . I. Human Anatomy, 81. situation, 81. rcdations, 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, 81. duct of the pancreas, 84. vessels, 80. arteries, 86. lymphatic vessels 86. nerves, 86. II. T^Iicroscopic Anatomy, 86. gland substance, 86. (/.. 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 coluninal-looking layer, and leaving a central space unoccupied, 89. duct, 89. capillaries, 00. III. (‘omparative Anatomy, 90. Invertebrata, 90. Gasteropoda, 90. Cephalopoda, 90. Vertebrata — Fishes, 91. pyloric appendages, 91. Keptilia, 94. IJatrachia, 94. Ophidian Reptiles, 95. Saurian Reptilia, 95, Clielonia, 95. Aves, 96. table of pancreatic ducts in several orders of birds, 97. lilammalia, 98. IV, Physiology, 99. resulis of analyses of pancreatic secretion, 102. function of the pancreatic Ihiid, 105. V. Morl)id Anatomy, a. quantitatively perverted nutrition, 108. Iiypertrophy, 108. afropliy, 108. induration, 100. softening, 109. b, inflammation, 109. r. hajiiiorrliage, 1 10. (/. structural changes, 110. 1. non-ma'ignant 5 cartilaginous tiansforma tion, no. sleatomatous concretions, 110. cystic tumours ; hydatids, 110 fatty degeneration, ill. 2. malignant, 111. scirrhus and carcinoma, 111. fungo-h?ematoid disease, 1 12. e, calculous concretions in the pancreatic duct, 1 12. occurrence of fatty stools in connection ^^Uh pancreatic disease, 112. Pelvis, 114. innominate bone, 114. its office, 1 14. superior border, 1 14. anterior border, 11 1. inferior border, 115. PelviSy 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, 1 16. internal or pelvic surface, 117. iliac tuberosity, 1 17. sacral or auricular surface, 117. internal iliac fossa, 117. ilio-pcctineal line, 117. internal structure of the innominate bone, 117. sacrum, 118. its office, 118. base, 118. apex, i 18. anterior or pelvic surface, 118. posterior surface, 118. lateral surfaces, 110. 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-luvnbar ligament, 124. great sacro-sciatic ligament fligamentum pelvis posticum magnus), 124. lesser or internal sacro-sciatic ligament (ligaraentum pelvis posticum parvum), 121. 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 ap))earance 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 lirim, 129. in the cavity, 120. 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-ischial 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. adiluctor group, 137. abductor group. 137. rotator group, 137. 3. muscles acting on the perineum and genitals, 138, posterior perineal group, 138. anterior perineal group, 138. fascial attacliincnts, 138. lumbar fascia, 138. abdominal fascia;, 138 crural fascia or fascia lata, 138, pelvic fascia, 138 perineal 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, 146. comparative anatomy of the pelvis, 148. pelvis of Negro, 148, 149. pelvis of the Busliman, 149. Tahitian, 150. Australian. l-'iO. 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 Simi$, 151 of the Carnivora, 154. FhoccC, 155. Pachydermata, 155. Rummantia, 157. Rodentia, 158. Marsupialia, 159. Monotrem;ita‘, 161. Kdentata, 161. Insectivora, 164. Cetacea. 165. Birds, 165. Reptiles, 170. Fish.^s, 172. table of comparativepelvic 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 equabiiiter justo major, 178. pelvis equabiiiter justo minor, 178. cause, 179. irregularities from imperfect development — infantile pelvis, 179. masculine pelvis, 180. irregularities of the pelvi-vertebral angle, 181. 2, distortions, 181 . distortions affecting the brim only or princi- pally, 181. distortions affecting the cavity only or princi- pally, 182. vertical flatness of the sacrum, 182. inward projection of the sciaticspines,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-j'ostcrior 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. sacTO-vertebral angle, 185. inclination of the sup(^rior plane, 185. cordiform or angular pelvis, 187. sacral promontory, 187. ilia and ischia, 187. pubic symphysis, 187. angles of the 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. cause of the obliquely deformed pelvis, 203. mechanism of this deformity, 204. obstructions caused by osteo-sarcoma- tous tumours, 200. obstructions from fibrous tumours at- tached to the pelvic ligaments, 206. effects of carcinomatous growth, 206, pathology of the pelvic joints, 206. ankylosis, 20^ coalescence of the bones composing the sa- cro-lumbar articulations, z07. ossification of the sacro-iliac joint, 207. ossification of the sacro- sciatic ligaments, 207. separation of the bones at their articular surfaces, 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. diagnosi', 210. Pcproduction^ Vegetable { Vegetable Ovum)^ 211. Part I. Algae, Fungi, and Lichens, 212, reproduction by means of zoospores, 212, under the most simple conditions, 212. confervoid Aigte, 213. the frond, 213. UlvacecB, 214. zoospores developed in an organ specia’ly des- tined to the purpose, 214. zoosporous reproduction in the olive-coloured Algae, 214. fructification in the Fucaceae, 215. the antherozoids of the Fucacere compared with the z *ospores of the other olive-coloured Algae, 216. zoosporous reproduction in the family of Vau- cheriaceac, 216. and in the Saprolegnia ferox, 217. Pilobolus, 218. zoosporous reproduction in some fungi, 218. reproduction by conjugation, 218. in Desmidiae, 218. in Zygnemaceae, 219. in Palmoglea macrococca, 220. condition utider which conjugation takes place among the Algae, 220. plants obtained by the germination of the zoospores of Saprolegnia, producing repro- ductive organs of an entirely different cha- racter, 220. reproductiveorgansofthered Algae or Florida?, 221 . the first form — a polyspore, 221. the second form — a tetraspore, 221. the third form — the antheridium, 221. reproductive organs of the Characeae, 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, 224. receptacle of Geaster fimbriatus, 225. the theca or ascus of fungi, 225, the ascophorous Fungi represented by Uredineje, 226. Discomycetes and Pyrenomycetes, 226. researches of IMIM. Tulasne, 227. formation and development of the germ in Li- chens, 228. the thallus, 229. the hypothallus, 220. 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 thecie, 230. antheridia of lichens, 230. pycnidis, 230. summary, 231. Part II. Higher Cryptogamia and Fhanerogamia, 232. vegetative system among the low’er Hepaticre, 232. first period — from the germination of the spore, 233. developnv^’nt of the .'intheridia, 233. deveb'praent of the archegot 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 — germmnti'-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, 23?. 3 B 2 732 ANALYTICAL INDEX Reproduction, Vegetable {Vegetable Ovum) '—continued . Ferns, 230. first period — germination of tlie spore, 230, antheridia, 230. archegonia, 210, origin of eacli archegonium, 249. the embryo, 241. sporangia and spores, 211. Eqiiisetacea?, 241 . lirst period — germination of the spore, 241, antheridium, 241 . archegonium, 242. spores and sporangia, 242. Fycopodiacese, 243. commencement of the development of the prothal- lium, 243. archegonia, 243, embryo, 243, sporangia and spores, 243, Rhizocarpcce, 245, macrospore of Pilularia, 245. pruthallium, 245, embryo, 215. sporangia and spores, 246. Plianerogamia, 246, Phanerogamia gymnospermia, 246. Phanerogamia angiospermia, 24S, tlippuris vulgaris, 219. Orchis morio, 250. the anther and the pollen-cell, 251. review of the analogies whieli jiresent themselves in the history of Uie development of the repro- ductive organs of the higher Cryptogamia and of the Phanerogamia, 252. 1. analogies existing between the ovule, the anther, and llie 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 arc 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, 258. lungs, 258. in man, 258. apices of the lungs, 258. trachea, 268. structural anatomy of the trachea, 259 tracheal mucous membrane, 259. cilia, 260. tracheal glands, 260. iibrous structures, 261. tracheal cartilaginous rings, 2C1. traclieal muscles, 262. arteries of the trachea, 262. bronchi, 2G2. the bronchi divide on no constant or regu- lar plan, 264. ultimate pulmonary tissue — lobules — historical bibliography, 2Gi. minute anatomy of the lobule, 266. ultimate air-cells of tlie lungs, — Vesiculae, s. cellulae aerete, s. Malpighianae ; alveoli puU monum of llossignol, 268. 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-cclls 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 Anaiomy. 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. air-bladder of Fishes, 281. lungs in Batrachia, 282. respiratory organs of Fishes, 2H6. mucous membrane of the branchia, 287. vascular system of the brancliia}, 2'<7. minute circulation of the branchiae, 288. cartilage, or supporting system of the branchiec, 289. Respiration, Organs of — continued, III. Morbid Anatomy of tlie lungs and air-passages, 291 inllamma'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, 203. inllammation of the vesicular tissue, 293. engorgement,, 293. hepatisation, 293. grey hepatisation, 293. gangrene, 293. cancer of the lung, 293. phthisis, 293. seat 01 pulmonary tubercle, 203. nature of tuberculous matter, 203. mechanism of emphysema, 293. Ruminmitia, an order of M immalian quadrupeds, 506. essential characters of the order, 506. and of the sub-orders — Camelidip, 506. Cervidas, 508. Antelopida*, 508. CEgosceridae, 508, Bovidae, 508. Osteology, 508. bones of the cranium, 509. 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, 616. horns, 516. vertebral column and bones of the trunk, 519. atlas in Camels, 520. axis or dentata, 520. dorsal vertebrie, 520. ribs, 520. pelvic bones, 521. bones of the anterior extremity, 521. scapuhv, 521 . 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. panniculiis carnosus, 523. musculus cutaneus faciei, 524. m. cutan. humeri, 524. m. cutan. maximiis, seu abdominis, 524, other muscles of the same category, 624. muscles of the head and trunk, 52 ). trapezius, 524. broad muscle represented in man by the splenius capitis and splenitis cervicis, 52*5. trachelo-mastoideus, 525. great complexus and digastricus colli, 525. transversalis cervicis, 525. scaleni muscles, 525. longus colli and recti, 526. sterno-mastoideus or maxillaris, 526. rectus capitis anticus major, 526. hyoid apparatus, 526. muscles proper to hyoid cliain of hones. 527» sterno-hyoids and sterno-thyroids, 527. omo-hyoid, muscle analogous to, 527. stylo-hyoid, 527. ceratoido-lateralis, 527. inasto-stylo.d, 527. mylo-h3^oid, 527. genio-hyoids, 527. muscles connected with the liyoid ap- paratus of the Girafle, 527. 733 TO THE SUPPLEMENTARY VOLUME. Ruminantia — continuchali in which the trunk is more developed, with an imperfect thorax, iv. 901. acephali with a trunk composed of a thorax and an abdomen, with superior and inferior limbs, iv, 902. acephali in which some cranial bones are found, iv. 902. body and extremities perfectly developed, having a neck surmounted by the ears, iv, 902. acephali composed of the trunk only, without indica- tion of limbs, iv. 902. Acephalia, i. 744; ii. 219; iii. 718. Acephalia spuria, iv. 954. See Acrania. Acephalonjst y 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. Accphalocystis endogena, or pill-box hydalid of Hunter, ii. 117. exogena, ii. 117. Acephalo-ctjsius, or hydatid, of the upper jaw-bone, ii. 220. Accrotherium^ the. See Paciiydeumata. Acervulas of Soemmering, iii. 035. Acephahus mollusks, iii. 304. See Mollusca. Acctahula^ or suekers, of Dibranchiata, i. 528. See Cepha- lopoda. Acctabuhwty i. 249; ii. 776; s. 110. eartilage of tlie acot.djuluin, ii. 777. libro-cartilage, ii. 777. fovea or sinus, ii. 777. glands of Havers, ii. 777, 778. incisura acetabuli, ii. 776. ligaments, ii. 777. supercilium aceiabuli, ii. 776. abnormal conditions of tlie, ii. 797. fractures of the, ii. 802—804. i brim, or circular border of, s. 116. Acetic acid, or vinegar, action of, on fibrin, iv. ICO. considered as an article of food, s. 395. Achagua Indian, portrait of, iv. l;P59. Achi'ta doinestica, or house-cricket, 804. Achillis tendo, i. 150. Achromatic lenses, how obtained, iv, 1438. Achromalopst/^ or insensibility of the eye to colours, iv. 1452. relative frequency of the affection, iv. 1453. hereditary tendency, iv. 1453. influence ofsex, iv. 14.54. hypothesis as to causes of this affection, iv. 1454. congenital achromatopsy, iv. 1454. dichromatic Daltonism of Wartmann, iv. 1454. polycliromatic Daltonism of Wartmann, iv. 1 455. list of the most common confusions of colour, iv. 1450. cases, iv. 1456, 1457. non-congenital achromatopsy, iv. 1157. permanent, iv. 1457. cases, iv. 1457, 1458. temporary, iv. 1458. cases, iv. 1458 — 1460. cause of the confusion of colours, iv, 1400. hypothesis, iv. 1400, 1401. rcmeuial measures, iv. 1401. Acini, ii. 4Hl . 483. of the liver, iii. 165. of duodenal gland, s. 361. Arms, .^MMAL, i. 47. See Bone; Fat; Milk; Urine. Acids, in animals and vegetables, i. 1 25. considered as articles of food, s. 395. Acurmiu, or congenital want, and defective formation, of the trunk, iv. 963. a. only a j)art of the head formed, iv. 903. />. superior parts of the body formed, without the in- ferior limbs, iv. 904. c. monopodia, iv. 964. ft. sympodia, iv. 904. r. original defective formation of the pelvis, iv. 965. /. defective development of the spinal column, iv. 905. Acorn-shelis, i. 083. See Cirrhopoda. Acoustic nerve, ii. 539. See Auditory nerve. Acoustics* See Hearing (physiology of) ; Sound. Acrania, what is the cause of, iv. 9.57. Acrid substance^ considered as alimentary, s. 395. Acrita (a primary division of the animal kingdom), i. 47. nervous system of the, iii. 601. Acromial artery, i. 300. 303. inferior branch, i. 364. superior branch, i. 303. Acromial nerves, iv. 753. communicating branches, iv. 753. communicans noni,or internal descending cervical iv 7.')3. Acromion process, i. 300 ; ii. 167, lo8 ; iv. 434, 000. fractures of the, iv. 600. mode of union, iv. 600. in Carnivora, i, 476. See Carnivora. Acrydium, nervous system of, iii. 010. Actinia, a genus of Polypifera, iii. 001. nervous filaments of tlie, 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 tlie integuments of, s, 484. Actinia alcyonoidea, a species of Polypifera, iv.30. sociata (Ellis), Zoanlhus (Cuv.), a genus of Poly- pifera, iv.20. Actiniadee, a family of Polypifera, iv. 20. 38, characters ot 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. numl'er and description of ova, iv. 40. muscular and nervous sy.stem 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. 1137. Actinophrys, or sun animalcule, iv, 12. mode of reproduction of the, s. 8. Actinurus, genus of Kotifera, iv. 407. Actions of animals generally, i. 141. Activity of animals, property of, iii. 35. generally proportionate to the respiration, iii, 35. See Locomotion. Aculcata, a section of insects of the order Hymenoptera, ii.865. characters of the section, il. 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 suturae lambdoidalis, i. 737. squamosee, i. 737. Adduction, a motion of joints, i. 256. Adductor brevis femoris muscle, s. 137. longus femoris muscle, s. 137. inagn .s femoris muscle, s. 137. magnus muscle, nerve (or, iv. 765. ossis metacarpi s, opponens, ii, 621. minimi di"iti, 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. 63. 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. 414. formation of callus, i. 444. theories of the process of, 414, 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. Adfu sion of the cranium, i. 746. Adhcsio7i, gelatinous, ii. 742. Adipocere, i. 55. discovery (>f, i. 55. chemical projiercies 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. jiroximate 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. 264. in insects, ii. 975. See Insecta. GENERAL INDEX. 7i3 Adventitious products. See PRt'DtrcTs, Adventitious. AerometeVy construction and mode of operation of the, iii. 32. 33. Afferent functions of nerves, iii. 720 I. nervous fibres, iii. 646. origin of the people of the group of African na- tions, iv. 1364. cranium of ihe natives of, iv. 1321, et seq. variety in the complexion of the different races of, iv. 1334. See Vauieties of Mankind. African group oflanguages, iv. 1347. African races, physical and mental characters of the, iv. 1352. See Negroes; Varieties of Mankind. Affusion of cold water, beneficial effects of, ii. 681. Agdlma Okenii (fig. 8.), i. 38. Agastrica, the term proposed, iii. .532. Agoiui, or deatb*struggle, a sign of approaching death, i. 800. Age, growth, i. 65. height, 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. 662. syncope caused by old age, i. 798. of organised bodies, i. 123. Agouti (Dasyprocta), anatomy of the, iv. 373, ct seq. mode of locomotion of the, iii. 454. Agrostis segetum, ravages of the larva of, in turnip-fields, li. 867. A'iy 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 of the rays of light transmitted through it, iv, 1438. bulk of the air expelled in expiration, iv. 352, effusion of, into the cellular tissue, i. 616. ai>paratus for renewing the air in the lungs of the human species, iv. 333. intermixture of air in the upper and lower respiratory appariitus, iv. 362. actions between the blood and the atmospheric air, iv, 362. atmospheric, changes effected in, by the respiratory apparatus of animals, i. 1.33; iv. 342. quantity of carbonic acid gas in the expired air, iv. 345. effects of period of the day, iv, 346. digestion, iv. 34G. fasting, iv. 347. alcoht)!, iv. 347. conditions of the mind, iv. 348. exercise, iv. 348. temperature, iv. 343. 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 rt-spiratory move- ments for a time, iv. 352. 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 frog, iii. 448. air swallowed by the Diodons and Tetrodon'l for the purpose of rendering themselves buoyant, iii. 437. sound transmitted by, ii. 566. temperature of the, effect of, in producing hibernation, ii. 765. influence of the natural temperature of the air on that of the human body, ii. 658. 680. modifications when the air is in motion or at rest, ii. 681. temperature of the, compared with the temperature of hibernating animals, ii. 770. .<^/r-bladder of fishes, forma' ion and uses of, iii. 436 ; s.281. wanting inRays, and the want how met, iii. 438, Air- bubbles, secretion of, iv. 145. yffr-cells, pulmonary, basement membrane of the, iii. 487 ; s. 268. See Lungs; Respiration, Organs of. minute structure of the. s. 270. epitlielium of the air-passages and cells, s. 270. elastic tissue of the air- cells, s. 272. vf/r-pass.ages of birds, i. 345. See Aves. A~tce, the Chinese heteradelph, iv. 969. Akya7io-blepsis. See Ackroynatopsy; Vision, Ala, or wing, of the ilium, s. 115. Alacta!>a (Mas jaculus), anatomy of the, iv, 372, et seq. AI(b majores, i. 726, 727; ii. 213.' anterior border, i. 728. anterior surface, i. 727. Ala: — continried. external border, i. 727. inferior surface, i. 727. posterior border, i. 727. superior border, i. 727. upper surface, i. 727. AliS minores, i. 726. 728 ; ii. 213. inferior surfaces, i. 728. upper surf.tces, i. 728. Afa cordis of insects, i. 206. Alee of nose, cartilages of the, iii. 726. Alar ligaments, i. 251 ; iv. 521, of knee, iii. 46, 47. veins, 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. 8.5. partial whiteness of the body in some cases, i. 86. physical causes — hypotheses, i. 86, 87. Dr. Sachs, the albino, iv, 1461. Albugineous fibre of Chanssier, 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. rediiCtionof 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. 1G7. 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, iv. 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. h. albumen retained, iv. 93. See also Ovum. Alhiuninaria, or albuminous urine, iv. 91. See Albumen. Alhuminose, 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]. Atcyonin, 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. 26—29. nutritirm of, iv. 27. mode of reproduction, iv. 27. gemmae, iv. 28. Alcyonidium stellatum, iv. 29. vascular system of. iv. 29. reproduction of, iv. 29, 30. Alcyonium bursa, electricity of the, ii. 82. ova of, s. [127]. Aleurites triloba, fat of the, i, 58. Algae, mode and organs ol reproduction of, s. 2)2. reproduct on by means of zoospon s, s. 212. under the most simple conditions, s. 212. the confervoid Alg», s. 213. the frond, s. 213. the Ulvaceee, s. 214. zoospores developed in an organ specially destined to the purpose, s. 214. zoosporous reproduction in the olive-coloured Algae, s. 214. fructification in the Fucaceae, s. 21.5, the antherozoids of the Fucaceae compared with the zoospores of the other olive-coloured Algae, s. 210. zoosp >rous reproduction in the family of Vau- cheriaceae, s. 216. 74i GENERAL INDEX, Alg. transversi perinjei 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. ha?morrhoids, i. 185. inflammation at the verge of the anus, i. 61. morbid conditions, i. 183. prolapsus ani, i. 184, Anus, abnormal condition -- continued. syphilis, i. 183. imperforate anus, cases of, in (hefeetus in utcro ii. 336. artificial, formation of, in cases of hernia, ii, 747— 7.50. circumstances connected with the healing of an ar- tificial anus, ii. 750. A7ivil-hone, or incus, ii. 546. development, ii. 560. abnormal conditions, ii. 561. Aorta, i. 11. 187- 220 ; ii. 3. arch of tlie, i. 188. abdominal aorta, i. 189, anomalies, i. 190. branches, i. 192. 1. branches arising from tlie arch, i. 102. right anterior or inferior coronary arlerv. 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. oesophageal arteries, i, 193. posterior mediastinal arteries, i. 193. inferior or aortic intercostal arteries, i. 193. anastomoses, i. 194. HI. branches of the abdominal aorta, i. 194. phrenic arteries, i. 194. coeliac artery, i. 194. coronary artery of the stomach, i. 191. 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. 196. lumbar arteries, i. 196. middle sacral artery, i. 197. sinuses, lesser, of the aorta, i. 189, development, i. 190. thoraeic aorta, i. 189; s 428. diseased conditions, i, 191.235; iii, 584. Aortic plexus of nerves, iv. 982; s. 429. Apes, iv. 195, et seq. See Quadrumana. conformation of, compared with that of man, iv. 1205, et scq. Aphaniptera, an order of Insecta, ii. 8G7. characters of the order, ii. 867. Aphides, or plant lice, ii. 865. 868. mo(le of generation of, ii. 416. 468; s. 33 — 38. 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. 1‘23. from exposure to cold or damp, iii. 123. a symptom of tubercular consumption, iii. 119. treatment of, iii. 123. Aplirodda aculeata, or sea-mouse, description of the, i. 617. nervous system of the, i. 168; iii. 607, 608. muscles of the, iii, 538. Aphthous ulceration of the tongue, iv. 1155. Apices of the lungs, s 258. ApidcB, or humble and hive-bees, ii, 865. food of, ii. 865. Aplidium, or Alcyonium, a genus of Tunicata, iv. 1189, ct seq. characters of the genus, iv. 1189. Aplysia, 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. 7-54. 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 lamellte 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 Aponeurosis — continued. of external oblique, ii. 840. of foot, ii. 3.52. 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. Aponeurotic septa, i. 217. Apoplexie fondroyante, i. 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. 720 O. appearances presented by the brain in cases of, iii. 720 D. common form of, i. 797. death by, i. 264. meningeal, cause of, iii. 716. spinal, cause of, iii. 713. Apotkecia of lichens, s. 227. Apparatus ligamentosus cavitatis siuuos?e, ii. 343. Appendices epiploic®, i. 57 ; iii. 943 ; s. 366. use, s. 366. Appendix., vermiform, structure of, s. 365. uses of, s. 365. development of the, s. 402, xiphoid, or ensiform cartilage, iv. 1023. ossification of the, iv. 1024. Appetite., state of the, in cases of phthisis laryngea, iii. 121. Apple of Adam, iii. 102. 112. 573. physiognomical character of, iii. 573. Aprosterni., a tribe of Insects, ii, 861. characters of the tribe, ii. 861. Aptera, an order of Insecta, ii. 86S. characters of the order, ii. 868. Apteryx^ 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. 868, Aquecducius cochle®, i. 7.34 ; ii. .533. 536. Aquaductus Sylvii, iii. 676. 693. 698. Aqiueductus vestibuli, 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. Aqinda Cotunnii, ii. .536. labyrinth! membranacei, ii. 539- ArahiUy circumcision of females in, ii. 636. Arabs., complexion of, in various parts of Arabia, iv, 1333. of Algiers, characters of the, iv, 1357. Arachnida (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. 6-52. digestive system, i. 1. 202; iv. 232; s. 298. divisions of the class, i. 193. 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 system, i. 211. ova of Arachnida, s. [1 14.] formation of ova, s. [114.] almost all oviparous, s. [115]. copulation, oviposition, and development of the ova, i. 211. exclusion or hatching of the spider, i. 214. locomotion, organs and mode of, iii. 544. metamorphoses, i. 215. muscular system, iii. 539. m*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, iii 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. Araneidce, or spiders, i. 198. abdomen, i. 201 . cephalo-thorax, 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 cousuraptioii 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 Arachnida. Arbor vit® 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, iii 925. of veins, superficial, iv. 1407. deep, iv. 1407. Arckegonia, development of the, in the higher Cryplogamia 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 ardform fibres of medulla oblongata, iii. 680. Arctomys, or marmot, anatomy of the, iv. 370, et seq. Arcuatum ligamentum, i, 11. Arcus interior of Senac and Haller, i. 11. senilis, or gerontotoxon. i. 80 ; ii. 178. Arenicola, or sandvvorm, organs of circulation in tlie, i. 6.50. 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. 247. 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. 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. brachi®us 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, il 47, et seq. See Edentata. pelvis of the, s. 163. Armenian language, iv. 1349. Arsenic, action of, on the vital power of the heart, i. 723. 7P7. 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. 3 c 2 7-1-8 GENERAL INDEX, A nxE R I Es — continued. contractions of arteries, i. 6'’)5. coats of, extf'rnal, i. 222. GG5. middle, i. 222. elasticity of, ii. 58. course of, i. 220, 221. definition of, i. 220. development, progressive, i. 225. distribution of blood, mechanism for facilitating, i. 223. G58. divisions of, i. 221. elasticity of, i. 224 ; ii. 58. form of, i. 220. globulus Arantii, or corpus sesamoidcum, i. 223. irritabilify of, i. 225. GG5. nerves of, i. 224. origin of. i. 220. pathological conditions of, i. 22G. physical properties of, i. 224. elasticity, i. 224. power of resistance, i. 221. sheaths for, i. 221. specific gravity of, i, 221. structure of, i. 221. tendinous rings, ii. 587. tonicity of, i. GG7. torsion of, i. 221. tunics external, middle, and internal, i. 222, 223. valves, i. 223 ; ii. .589. mechanism of, i. 223. varieties, influence of, in the distribution of arteries upon the circulation, i. 678. venaj comites, i. 217. vasa vasorum, of i. 223. vital properties of, i. G65. influence of, on the circulation, i. 667. See Cir- culation. Arteries (pathological condition of), i. 226. ligatures, i. 229. 234, 235. morbid state of arteries, i. 230. aneurism, i. 230. aneurismal varix, i. 230. aneurism by anastomosis, i. 242. circumscribed false aneurism, i. 232. diffused aneurism, i. 237. traumatic aneurism, i. 237. true aneurism,!. 235. varicose aneurism, i. 242. torsion of arteries, i. 224. 228. wounds and injuries of arteries, i. 227. arteritis, i. 226. 232. gun- and cannon-shot wounds, i. 227. hsemorrhagp, arterial, i. 228. internal haemorrhage, and open or bleeding arteries, i. 233. natural suppression of, i. 229. permanent suppression of, i. 229. secondary haemorrhage, i. 238. calcareous deposits in the coats of arteries, iv. 87. atheromatous matter, iv. 87. white spots, iv. 87. cartilaginous patches, iv. 87. softening of the internal membrane of arteries, iv. 708. Arteries, or Artenj, in particular; — abdominal, i. 14 ; iv. 823. acromial, L 363. alveolar, i. 490. anastomotica magna, brachial, i. 466. of thigh, ii. 249. angular, of face, i. 487 ; iii. 93. aorta, i. 187. 220. abdominal, i. 189. arch of, i. 188. anomalies, i. 190. branches, i. 192. sinuses, i. 189. thoracic, i. 189. articular, superior external, iv. 64. internal, iv. 64. superficial superior internal, ii. 219. articular, of knee, inferior, iii. 48. middle, iii. 48. superior, iii. 48. auditiva, interior, li. 542. auricular, posterior, i. 448 ; ii. 542. 556 ; iii. 903. profunda, ii. 556. axillary, iii. 248 ; iv, 616. axis, cadiac, i. 189. 194. azygos, iv. 64. basilar, i. 236 ; iii. 674. 678. 704 ; iv. 820. branches, iv. 821. of bones, i. 434. 436. brachial, i. 216, 217 ; ii. 64. 363 ; iv. 1407. of brain, iii. 704. bronchial, i. 189. 193; s. 275. superior, s. 275. inferior, s. 275. buccal, i. 489 ; ii. 227. of bulb of clitoris, s. 713. of bulh of penis, iii. 934 ; iv. 1254. caecal, i. 196. Arteries — continued. cardiac, li. 192. carotid, i. 482 ; iii. 704. carotid, left, i. 189 ; iv. 820. external, i. 484 ; iii. 93. 1 10. 003. branches, i. 485—490 ; iii. 93. 1 10. internal, i. 490 ; iii. 93. branches, i. 491 — 493; iii. 93. to F.ustachian tube and promontory, 556. carpal, of radial, ii. 529 ; iv. 225. 1506. anterior, iv. 223. dorsalis, iv. 223. carpi ulnares posterior, iv. 225. anterior, iv. 225. central of retina, iii. 786. cerebellar, inferior or posterior, iv. 821 . superior or anterior, iv. 821. cerebral, anterior, i. 493. middle, i. 493. posterior, iv. 821. cervicalis profunda, i. 367. ascendens, iv. 824. superficialis, iv. 824. choroid, i. 492. ciliary, i. 491 ; iii. 786. anterior, i. 492. middle or long, i. 491. posterior or short, i. 401. circumflex iliac, i. 15 ; ii. 842. anterior, i. 364. posterior, i. 364 ; iv.43fi. circumflexus scapulte, i. 364; iv. 436. coccygeal, ii. 834. cochlear, ii. .542. coeliac, or coeliac axis, i, 189. 194. colic, right, i. 195, 196; s. 379. middle, i. 195, 196 ; s. 379. left, s. 380. comes nervi phrenici, iv. 822. communicans ulnte, iv. 226. coronaria ventriculi, s, 325. coronary, of heart, i. 189. 192. 194 ; ii. 584. labial, inferior, i. 486. superior, i. 487. of corpus cavernosum, ii. 836. corporis bulbosi penis, iii. 916. cavernosi penis, iii. 916. corpus spongiosum, iv. 1254. of cranium, i. 748, 749.. of crus penis, iii. 934. cystic, i. 195. dental, or maxillary, i. 489 ; ii, 227. diaphragmatic, ii. 4, inferior, ii, 227 superior, ii. 227. digital, iv. 226. 1407. dorsalis lingua?, iv. 1141. dorsal of foot, ii. 352. clitoris, s. 709. 713. ear, external, .and tympanum, ii. 656. penis, iii. 917; iv. 1254. hand, iv. 223. of dura mater, iii, 629. of ear, ii. 856. epigastric, deep, i. 15; ii. 842. superficial, i. 14 ; ii. 244. emulgent, or renal, i. 189 ; iv. 235. ethmoidal, anterior, i. 492 ; iii. 786. posterior, i. 492 ; iii. 786. of eye, iii. 93- facial or labial, i. 486 ; ii. 227. 556 ; iii. 93. 733. 949 transverse, ii. 227 ; iii. 903. of Fallopian tube, s. 603. femoral, i. 228. 230. 235 ; s, 713. fibular, ii. 235. of fore-arm, ii. 363. frontal, i. 492 ; iii. 786. gastric, i. 194 ; s. 325. gastro-dnodenalis, s. 326. gastro epiploic, i. 194 195 ; s. 327* left, s. 327. right, s. 326. gluteeal, or posterior iliac, ii. 250. 833, haemorrhoidal, external, ii. 835. inferior, i. 196 ; s. 380. middle, i. 386. 830. s. 380. superior, i. 196. of rectum, i. 181. helicin®, ii. 146 ; iii. 917. hepatic, i. 194, 195 ; iii. 171 ; s. 326, of hip-joint, ii. 779. hyoid, i. 485 ; iv. 1 141. hypogastric, i. 386. ileo-colic, i. 195, 196 ; s. 379. iliac, external, ii. 250. 837. internal, i. 181 . 386 ; ii. 250. 828 ; s. 640. primitive, i. 189. superficial anterior, ii. 244, ilio-lumbar, ii. 250. 829. infra-orbital, i. 490{; ii. 227 ; iii. 93. iiifra-spinal, iv. 435. GENERAL INDEX. 749 Arteries — continued. innominale, i. 189. 233; ii. 850; iii. 580 ; iv. H07. left, iv. 819. intercostal, i. 189. 193. 3G7 ; iii. 248. dorsal branches, i. 3G7. intercostal, anterior, iv. 822. superior, iv. 824. interlobular, iii. 171. interosseal, posterior, ii. 364. interosseous, iv. 225. intestinal, i. 195; s. 379. irregular, of prostate gland, iii. 933. ischiatic, ii. 833. of knee, iii. 48. labial or facial, i. 486. lachrymal, i. 491 ; iii. 93. 786. laryngeal, of superior thyroid, i. 485. of larynx, iii. 1 10. of leg, iii. 133. lingual, i. 485 ; iv. 1 141. hyoid of, i. 486. lobular, iii. 171 . lumbar, i. 189. 367. magna pollicis seu princeps of hand, iii. 224. of mamm®, iii. 248. mammary, internal, iii. 248 ; iv,822. malleolar, i. 150. internal, i. 150. masseteric, i. 489. maxillary, external, i. 486; ii. 227. internal, i. 489 ; ii. 227. 556; iii. 93. 733. 903. branches, i. 489, 490. or inferior dental, i. 489. of membrana tyrapani, ii. 5.56. median, anterior, iii. 656 ; iv. 821 . mediastinal, i. 193 ; iv. 822. meningeal, accessory, ii. 556. inferior, iii. 630. posterior, iii. 630. middle, i. 489. 734 ; ii. 556 ; iii. C30, posterior, i. 487. 731. mesenteric, inferior, i. 189. 196 ; s. 380. superior, i. 189. 195; s.379. metacarpal, of radial, ii. 629. modioli centralis, ii. 542. muscular, of orbit, i. 492. inferior, i. 492. superior, i. 492. musculo- spiral, ii. 160. musculo.phrenic, iv. 823. nasal, i. 487. 492 ; iii. 733. 786. dorsal, i. 487. external, common, i. 487. lateral, i. 487. ofseptum, i. 487. nutritia liumeri, i. 466. obturator, ii. 250. 831. 843. occipital, i. 367. 487* 748 ; ii. 542. 556. oesophageal, i. 193 ; iii. 759. oniphalo-mesenteric, i. 196. ophthalmic, i. 491 ; ii. 227 ; iii. 93. 733. 785. ethmoidal branch, i. 730. ovarian, s. 552. 640, palatine, inferior, i. 486 : ii. 556 ; iii. 949. superior, i. 490 ; ii.556. palpebral, inferior, i. 492 ; iii. 93. 786. superior, i. 492 ; iii. 93. 786. pancreatic, great, i. 195 ; s. 86. small, i. 195. pancreatico-duodenal, i. 194; s. 86. 326. perineal, ii. 835 ; s. 713. superficial, iii. 928. transverse, iii. 929. of penis, ii. 145, 146; iii. 916, 917 ; iv. 1254. perforating, of fore-arm, iv. 224. peroneal, i. 150 ; ii. 267 ; iii. 134. anterior, ii. 267. posterior, ii. 267. pharyngeal, inferior or ascending, i. 487 ; ii. 556 ; iii. 949. superior, i. 490. phrenic inferior,!. 189. superior, iv. 822. popliteal, ii. 243 ; iii.4S; iv. 62, profunda clitoridis, s. 713. femoris, ii. 244. humeri, inferior, i. 217. 465. superior, i. 217. 465. penis, ii. 146. of prostate gland, iv. 150. pterygoid, i. 489. pterygo-palatine, or superior pharyngeal, i. 490. pubic, internal, i. 386; il.843. pudenda, external, superior, s.713. inferior, s. 713. pudic, i. 181 ; ii. 244. 250 ; iii. 931. 934 ; s. 713. external or superficial, inferior, ii. 244 ; iv. 439. pudic, external or superficial, superior, ii. 244 ; iv. 439 ; s. 713. internal, i. 181; ii. 834. pulmonary, i. 220; ii. 598 ; s. 273. Arteries — continued, pyloric, inferior, s. 326. superior, i. 194 ; s. 326. radial, il. 363. 526. 529 ; iv. 221. 1407. radialis indicis, iv. 224. ramus pinnalis, i. 487. ranine, i. 485 ; iv. 1141. recurrent, of radial, iv. 223. of ulnar, anterior, iv. 225. posterior, iv. 225. renal, i. 189 ; iv. 235. of retina, central, i. 491. sacral, lateral, ii. 830. middle, or anterior, i. 197; ii. 828. satellite of right subclavian, iv. 816. brachial, iv. 1407. sciatic, ii. 250. scapular, posterior, i. 367 ; iv. 436. 824. septi nasi, i. 4h7. soporifer®. See Carotid. spermatic, i. 189 ; ii. 844 ; iv. 981. 983 ; s. 552. 640. spheno-palatine, i. 490. spinal, anterior, i. 731 ; iii. 656. 704. posterior, iii. 657. 704. splenic, i. 195 ; iv. 7H7 ; s. 326. for sterno-mastoid, i. 488. of stomach, s. 325, 327. stylo-mastoid, ii. 542. 556. subclavian, iii. 577, 578. left, i. 189. 230 ; iii. 110. right, iv. 814. 816. sublingual of lingual, i. 486 ; iv. 1 141. submental, i, 486. subscapular, i. 364 ; iv. 436. supra-orbital, i. 491 . 748 ; iii. 93. 786. of supra-renal capsules, iv. 833. supra-scapular, iv. 824. supra-spinal, iv. 435. superficialis vol®, iv. 223. temporal, i. 488 ; ii. 227. 556. anterior, i. 488 ; iii. 93. deep, i. 489. 748. middle, i. 488. posterior, i. 488. deep, i, 489. superficial, i. 748. thoracica acromialis, i. 360. 363. iv. 818. alaris. i. 358. humeraria, i. 359. longior, i. 358, 364 ; iii. 249. suprema, i. 359, 360. 364. thymic, iv. 822. thyroid axis, iv. 823. thyroid, inferior, iii. 759 ; iv. 823. 1 106. superior, i. 485. ii. 831 ; iii. 1 10 ; iv. HOG. middle, ii. 851. tibial, anterior, i.l50 ; ii. 355 ; iii. 131. posterior, i. 150 ; ii. 354 ; iii. 133. recurrent, iii. 131. tonsillitic, i. 486 ; iii. 949. of tongue, iv. 1141. of trachea, s, 262. transversalis colli, i. 367 ; iv. 436. 824. transverse facial, ii,227 ; iii. 93. of humerus, iv. 435. perineal, iii. 929. tympanic, inferior, ii. .556. superior, ii. 556. ulnar, ii. 363 ; 525. 529 ; iv. 221. 1407. umbilical, i. 220. urethra, iv. 1254. 1264. of urinary bladder, i. 386. uterine, ii. 831 ; s. 5.52. 640. vaginal, ii. 831 ; iii. 171 ; s. 706. vas deferens, iv. 983. vasa brevia, i. 15 ; s. 237. vertebral, i. 731 ; iv. 816. 819, 820. vesical, ii. 830. vestibular, ii. 542. vidian, i. 490 ; ii. 556. Willis’s lateral, or posterior communicating branch of internal carotid, i. 492. of villi of intestine, s. 351. Arteriuliths, iv. 88. Arteriotomy oi pericranium of temporo-parietal region, i. 749. Arteritis^ acute, i. 226. 232. Arthritic concretions, — tophi or gouty concretions, iv. 90. chemical composition of, iv. 91. Arthritis cox®, acute, ii. 790. anatomical characters, ii. 792. cases of, ii. 790. 791 . chronic strumous arthritis cox®, ii. 793. anatomical characters, ii. 795. cases of, ii. 795, 796. chronic rlieumatic arthiitis cox®, — chronic rheuma- tism, ii. 798. anatomical characters, ii.801. genu, acute, iii. 49. case of, iii. 54. combined with acute osteitis, iii. 64. 3 c 3 7.50 GENERAL INDEX. Arthritifi gmu, acute — contimiecf. combined with necrosis, iii. G4. chronic simple, lii. 55. rheumatic, iii. .57. strumous, iii. fiO. of the ra«iio-cnrpal and of the inter-carpal articula- tions, acute, iv. 1523. clironic rheumatic of wrist-joint, iv. 1.52fi. chronic strumous, or white swelling, of the wrist, Iv. 152-1. of the shoulder, acute, iv. 577. symptoms, iv. 577. anatomical characters of ar- thritis of tiie shoulder, iv. 577. chronic, iv. 577. chronic rheumatic, of shoulder joint, iv, 584. symptoms, iv. 584. diagnosis, iv. 585. anatomical characters, iv, 585. chronic rheumatic, of the tcmporo-niaxillary articu- lation, iv. 939. Articvlnr arterits of knee, superior, iii. 48. middle, iii. 48. inferior, iii. 48. superior external, iv. 04. artery, superficial superior internal, ii. 249; iv. 04. course and relations generally, ii. 249. eminence, i. 734. facets of sacrum, s. 118. fossa, i. 734. nerves, iv. 7C8. superior external, iv 7G8. inferior external, iv. 708. superior internal, iv. 709. processes of sacrum, s. IIH. tubercles of sacrum, s. 119, vein, iv. 1411. Arthrodia^ i. 256. characters, ligaments, and motions, i. 250. Arthropoda, ova of, s. [110]. AUTicttLATA (a primary division of the animal kingdom), i. 1. 244. subdivisions, i. 245, 240. I. Cirripeds, i. 245. See also CianiPEDA. 1!. Annelidans, i. 245. See also Annelida. HI. Insects, i. 240. See also Insecta. IV. Araclinidans, i. 246. See also Arachmda. V. Crustaceans, i. 240. See also Crustacea. organs of circulation in,i. G50. biliary apparatus of, iv. 446. nervous system of the, iii. 600, 607. ova of .^rticulata, s. [1 10.] spermatozoa of Articulata, iv. 488. Articulation, or Joint, i. 246. forms and classification of the articulations, i. 2.5-1, diarthrosis, i 25-5. arthrodia, i. 2.50. rotatorius, i. 250, enarthrosis, i. 250. ginglymus, i. 2-56. synartiirosis, i. 2.51. amphiarthrosis, i. 255. gomphosis, i. 2.55, schindylesis, i. 255. suture, i. 254. structures entering into the composition of joints, i. 247. bone. i. 247, cartilage, i. 247 ; iv. -522. various forms of articular cartilage, i. 247. diarthrodial, i. 248. synarthrodial, i. 249. fibro-cartilage, i. 249. menisci, i. 249. tibro-cartilages of circumference, i. 249. fibro-cartilaginous larninaj, i.250. lig-aments, i. 250. capsular, i. 2.50. elastic, i, 251, funicular, i. 251 . synovial membrane, i. 251, the articulations in old age, i. 79. ollice of the joints witli respect to locomotion, iii. 415. influence of the atmosphere in keeping the joints together, iii. 41-5, 410. Articnlndonn^ in paiticular. aslragalo-calcanien, anterior, ii. 342. posterior, ii. 342. astragalo-scaphoid, ii. 343. ralcaneo-cnboid, ii. 313. carpal, ii. 508. motions of the, ii. 508. carpo-metarcapal, ii. 509. ofthe tiuimb, ii. .509. chondro-sternal, iv. 1032. costo-vertebral, iv. 1032. of cranial bones, i. 7.30, crico-arytenoid, iii. I(i5. crico-tbyroid, iii. 104. Articulalions — continued. cuboido cuneen, ii. 343. cnneo-scaphuid, ji.313. of fingers, ii, 510. hip-joint, ii. 790. intra-coccygeal, s. 122. of the larynx, iii. 103. extrinsic, iii. 103. intrinsic, iii. 104. lumbo.pelvic, s. 121 . of maxillary, superior, i. 729. nietacarpo-piialangeal, ii. 510. metatarsal, ii. 3i5. metatarso-])balangeal, ii. 345, of nasal bone, i. 7^9. of pelvis, s. 121. phalangeal, of fingers, ii. 510. pubic sjmphysis, s. 125. radio-carpal, iv. 1505. radio-ulnar, iv. 228. sacro-coccygeal, s. 122. sacro-iliac, s, 122. 207. sacro-lumbar, s. 207, scapulo-humeral, iv, 573. shoulder joint, iv. .571. sphenoid bone, i. 728. tarso-metatarsal, ii. 31-1. temporo-maxillary, iv. 937. libio-fibular, iv. 1 118. of the toes, ii. 343. tracheo-cricoidean, iii. 104. Articxdatiom of insects, ii. 881. See Insecta. Artificial legs, remarks on the application of, iii. 130. Arvicola amphibius, or water-rat, iv. 389. Aryteno-epiglotlic folds, iii. 101. HI. Arytcno-cpiglotlidei muscles, iii. 110. action, iii. 1 10. Ayrienoid Cd.ri\\7\%QS, iii. 102. gland, iii. 110. muscles, iii. 101, 107. obliquus, iii. 107. trausversus, iii. 107. AscarideSy ii. 1 1.3. ovum of, s. [120.] Ascaris lumbricoides, or round- worm, ii. 125. description of, ii. 12-5, 129. 135. 143. parts of the bfidy infested by, ii. 125. nervous system of the, iii. 607. organs of digestion of, s. 296. Ascaris mystax, development and fecundation of the ova of, s. [120]. development of spermatic corpuscles in, s. [121]. Ascaris vermicularis, or worm of the larger intestines, ii. 125, 126. Ascidia, a genus of Tunicata, iv. 1187. characters of the genus, iv. 1 187- mode of reproduction of the, s. 23. Ascidia mammillata, nervous system of the, iii. 60.3. AscidiadeVy a family of Tunicata, iv. 1187, el scq. characters ofthe family, iv. 1187. genera, iv, 1187, 1188. ciliary motion in the, i. 623. Ascidium acuminatum, mode of reproduction of, s. 212. Ascites, analysis ofthe elfusion of, iii. 483. displacement of the diaphragm from, ii. 6, enlargement of abdominal veins attendant on, i. 1-5. increase of capacity of the bladder mistaken for, i. 395. Ascus, or theca of fungi, s. 225. Ashanli, physical and mental characters of the, iv. 13-53. Asia, High, the people of, probably the stock from which the globe was originally peopled, iy. 1364. races of, principal characters of the, iv. 1349. groups into which the Asiatic nations may be arranged , iv. 1350. Seriform stock, iv. 13-50. Turanian stock, iv. 1351. Peninsular Mongolidae, iv. 1351. Hyperborean Mongolidte, iv. 1351. Syro-Arabian, or Semitic, nations, iv. 1351. capacity of a skull of a Hindoo Brahmin, iii. 066. Asilidcu, ii. 807. Asilus crabroniformis, ii. 807. Asiniis vulgaris, — organs of voice of the, iv. 1492. See Ass i Equus Asinus. Asphyxia, i. 257. phenomena of, in the higher animals, i. 2-58. in the lower animals, i. 258, 2.50. appearances after death, i. 259. appearances of the brain in fatal cases of, iii. 720 F. by carbonic acid, condition of the epiglottis in cases of, iii. 123. 125. opinions of physiologists respecting, i. 260, changes in the blood of the pulmonary capillaries and arteries in, i. 677. syncope by, death from, i. 794. AspidiscinidcE (shield animalcules), a family of Polygastric animals, iv. 5. characters of the family, iv. 5. Asplenium septentrionale, archegonium of, s. 240. Asps, or hooded snakes (Naja), poison fangs of, iv. 291. GENERAL INDEX. 751 1 /iss (Eqims Asinns), Iv. 714. organs ol‘ voice of the, iv. 1 192. milk of the, iii. 362; s. 391. analysis of tlie, iii. 362. I Weberian organ of the, iv. 1420. Assassin, M. Sylvestre de Sacy’s derivation of the word, iv. 691, note. Assimiiaiion in animals, i. 144. ; Association, instinct of. See Congrcsation ; Instinct. > Aslacus aflinis, biliary organs of, iv. 448. fluvialilis, or river craw-fish, ovum of, s. [115], note, I (lobster), nervous system of the, iii. 613. ' Astasieadce, a family of Polygastric Animals, iv. 4, et scq. yfiTifrms, or scar-fish, ii. 31, scy. See Echinodermata, cilia in, i, 615. See Cilia. ova of Asterias, s. [125]. biliary apparatus of, iv. 446- nervous system of the, iii. 602. organs and mode of progression of the, iii. 440. alimentary canal of, s, 297. muscles of the, iii. 537. Aslhwa, exciting causes of, s. 293. of infants, or spasmodic croup, described, iii. 124. hypotheses as to causes of, iii. 124. thymic, of Kopp and Hirsch, iii. 124 ; iv. 1102. f Astigmatic lens of Professor Stokes, iv. 1468. Astragalo scaphoid articulation, ii. 343. ligament, ii. 343. Asti'agalo-calcanicn, anterior, articulation, ii. 312. posterior, ii. 342. Astragalus, i. 152; ii. 339. I structure and development, ii. 341. ; abnormal conditions of the, ii. 347. ; Astrea abnormalis, a genus of Polypifera, iv. 37 ‘ Alelt's, a genus of Quadrumana, iv. 210, ct scq. See Qua- 1 DRUMANA. characters of the genus, iv. 210. Alhalia centifoliee, or saw-fly, — ' organs of generation of the, ii. 992, 993. ravages of its larva in turnip fields, ii. 865. 870. Atheroma, i. 64^; iv. 97. Atheromatous deposits in the coats of arteries, iv. 87. in the carotid artery, i. 494. in the liver, iii. 183. in the scalp and eyelids, iv. 97. I in veins, iv. 1402. I of Dr. Latham, iv. 1358. Atlas of camels, s. 520. ; Atlas motli, size of the, iii. 423. Atmosphere, mechanical effects of atmospheric pressure on . animal structures, iii. 412. 415. 424 1 resistance of air, effect of, on animal motion, iii. 113. 419. I " Atomic Theory” of Dr. Daubeny quoted, iii. 159. . Atoms, ultimate, of matter, theory of, iii. 356. Atony of the muscles of the larynx, iii. 123. . Atresia ani urethralis, iv. 951. 969. narium, iii. 737. urethras, iv. 1256. • Atrium vaginas, or vestibulnm, iv. 1425. I Atrophy (in morbid anatomy), ii. 827. ' Atrophy in particular : — • of the bones, i. 443, 444. of the face, ii. 220. of the brain, iii. 720. marks of an atrophied state of brain, iii. 720. , senile atrophy, iii. 720. parts in whicii partial softening of the brain occurs, iii. 720 B. of the cranium, i. 745. of the epiglottis, iii. 122. of the foetus in utero, ii. 318. of the heart, ii. 642. of the liver, iii. 188. of the lung in aged persons, i. 78, note, of the muscles of the larynx, iii. 123. ol nerves, iii. 720 G. of the ovary, s. 573. oftlie pancreas, s. 108. of the prostate gland, iv. 150. of the spinal cord, iii. 714. of the testicle, iv. 991 . wasting, iv. 992. arrest of development, iv. 991. of the tibia in old persons, iii. 69. of the tissues : decrease of the nutritive processes, iii. 752. ; of the tongue, iv. 1 159. of the uterus, s. 686. of the valves of the heart, ii. 647. of the vagina or uterus, s. 618. AttoUens auriculam muscle, ii. 551. \ Attrakens auriculam muscle, ii. 552. i clitoridis, s. 713. j Audition. See Sound. Auditory apparatus of Fishes, iii. 1002. external foramen, i. 733, ’ internal foramen, i. 733. meatus externus, i. 733. • internus, i. 733. \ muscles (in comparative anatomy), iii. 5M. nerve, ii. 272. 530.539.; iii. 597, 707. Auditory apparatus of Fishes — continued. cochlear branch, ii. 540. nerve, vestibular branch, ii.540. third, or lowest, branch, ii. 540. peripheral expansion of the, iii. 597. lobule of the, iii. 692. development of the, ii. 558. passage. See Meatus auditorius. process, external, i. 733. Auloxoa (tubular polyps), a sub-class of Polypifera, iv. 20. 40. Aura seminalis, hypothesis of an, ii. 466. See Generation. Aural system of muscles, iii. 544. Aurelia, or pupa, form of insects, ii. 879. origin of the term, ii. 879. Aurelia aurita, mode of progression of, iii. 433. phosphorea, organs of digestion of, i. 43. Auricle, or auricula s. pinna, of ear, ii. 550. development and abnormal conditions, ii. 561. nerves of the, ii. 555. office of the, in tlie function of hearing, ii. 571 . 577. See Hearing, Organ of. Auricles of the heart (or pars cordis venosa), i. 633. capacity of the,i. 657, 658. See Heart (normal anatomy). Auricula dextra vel infeiior, atrium venarum cavarum, ii. 597. See Heart (normal anatomy), sinistra vel posterior, atrium seu sinus venarum pul. monalium, a. aorticum, ii.582. See Heart (normal anatomy). Auricular artery, posterior, i. 488. 748; ii. 542. 556; iii. 903. profunda, ii. 556. muscles, i. 749. nerves, external, ii. 294, internal, ii. 293. communicating branches, ii. 294. great, ii. 555; iii. 571. 903; iv. 753. brandies, iii. 903; iv. 753. auricular, superficial, hi. 903; iv. 753. deep, iii. 903; iv. 753. posterior, iv. 546. or iliac, articular surface of sacrum, s. 1 19. or maxillary, process, ii. 213. or Otic ganglion of Arnold, ii, 292. See Sympathetic Nerve. vein, posterior, iii. 903. Auriculo-tempural nerve, iii. 903. Am icnlo-ventricular tendinous rings, ii. 587. Auriculo-ventricular openings, ii. 5S0 — 587. tendinous structure in the, ii. 589. Australasia, peculiarity of all the known aboriginal mam- mals of, iii. 257. Australia, cranium of an aboriginal Australian, iv. 1326. portrait of an Australian chief, iv. 1363. physical and mental characters of the Australian abo- rigines, iv. 1363. affinities between the language of, and the Tamu- lian of Southern India, iv. 1363. pelves of natives of, s. 1-50. causes of the tendency to extinction in the aborigines of, iv. 1341. 1365. Western, cranium of a native of, iv. 1320. Autumn, why in some latitudes less dangerous than spi ing, ii. 681. Aves. i. 116. 265. absorbent .«;ystem. i. 327. ciliary motion of birds, i. 631. circulation, organs of, vascular system — heart, i. 329. arteries, i. 332. veins, i. 338. chyliferous system in, i. COl. digestive organs of birds, s. 301. stomach, s. 301. oesopha^,us, s. 301 . ingluvies or crop, ii. 11 ; s. 301. proper stomach or proveutriculus, s. 301. gizzard, ii. 11 ; s 301. intestine, s. 301. glands, i. 325. divisions into orders, i. 266. fossil bones of birds, i. 289. generation, organs of, i. 3-=<3 ; ii. 431. compared witli those of quadrupeds, ii. 453, note. male, i. 353. spermatozoa, ii. 1 12 ; iv. 477. female, i. 355. relation of the ova to the ovary of birds, s. 58. detailed description of eggs of birds, s. 60. quantity of matter, composition, &c. s. 60—63. structure of the external parts of the egg, s. 50. 63. ehalaza? (grandines), s. 64. formation of the external or accessory parts of the bird’s egg, s. 65. ovarian ovum of birds ; ovulum ; yolk aud its contents, s. 68. microscopic structure of the ovum, s. 71. yellow or external yolk substance, s. 71. substance of the cavity and canal, s. 72. cicatricula and cuirmlu.s, s. 73. 3 c 4- 752 GENERAL INDEX. AvfiS, microscopic structure of ovum — continued* vitelline membrane, s. 74. early condition and Hrst formation of the ovarian ovum in (>irds, s. 74. morphology of the bird’s egg, as ascer- tained from its first origin and develop- ment, s. 1^. heat, animal, of, ii. 649. G05. instincts guiditig association of birds, iii. 18. guiding Incubation, iii. 14. guiding migration, iii. 12 guiding modification, iii. 14. liver of birds, lii. 17'». niarsupium nigrum in, ii. 203. uses of the, ii. 201. myology, i. 290. cUiubing, i. 297. divinir, i. 297. fiiglit, 207. velocity of birds, iii. 429. powers of flight of birds, iii. 424. use of the tail in fiigln, iii. 429. See Motion, Animal. ]irogression on land, i. 297 ; iii. 4r>0. sailing, i. 297. swimming, i. 297. nervous system, i. 303 ; iii. 021. ’ brain, i. 298. hearing, organ of, i. 308 ; ii. 53G. lachrymal organs, i. 307. ta.sre, organ of, i. 31 1. touch, organs of, i. 31 1. vision, organ of, 1. 303. optic nerves of, iii. 704. chiasina of tlie optic nerves in birds, iii, 769. eyelids in, iii. 9"). eyelirows 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. 16-5. table of the number of toe phalanges in birds,!. 289. table of the number of vertebra; in birds, i. 272. pancreas of birds, s. 9i>. table of numbHi* of pancreatic ducts in several orders of birds, s. 97. peculiar secretions, i. 349. renal organ, iv. 233. resjiiratory organs, i. 341 ; iv. 331. 1021 ; s. 276. air-passages, i. 34.5. salivary glands, i. 316. snpra-renal glands, i. 348. tegumentary system, i. 349. development of feathers, i. 35). 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-maxiUar\ articulation in, iv. 041. vocal organs and voice of birds, iv. 1 195, et scq. Aves aerese of Nitzsch, i. 266, altrices, a division of Birds, i. 266. aquaticae of Nitzsch, i. 266. aquatic birds, mode of progression of tlie, iii. 438. praBCOces, a division of Birds, i. 2GG. terrestres of Nitzsch, i. 266. Axilla (surgical anatomy) i. 216, 217. 358. anterior wall, i. 359. inner wall, i. 360, 361. lympliatic 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. 656 Axillary artery, i. 300. 3G3 ; iv. 248. branches, i. 363. 1. acromial, i. 363. 2. superior thoracic, i. .364, 3. inferior thoracic, i. 364. 4. subscapiilar, i. 364. 5. posterior circumflex, i. 3G4. 6. anterior circumflex, i. 364. relations, i. 363. lesion of the axillary artery complicated tvitli luxation of the head of the humerus, iv. 610. aneurism, i. 233. lymphatic glands, i. 368 ; iii. 231. nerve, iv. 7*59. plexus, ii. 361 . vein, i. 360 ; iii. 249 ; iv. 407. Axiotoma Gaedii, i. 38. Axis of cochleee, ii. 531 . cceliac, s. 325. .^.r/s-cylinder of Rosenthal and Purkinjie, iii. 592. organs of respiration in the, i. 99 ; teeth of the, i. 95. Axungia articularis, secretion of, i. 253. Aye-aye ofMadagascar (Cheiromys psilodaclylus), iv. 221. anatomy of the, iv. 374, et scq. Azote, absorption and exhalation of, by the lungs, ii. 149. AZYGOS, the term, i. 364. Azygos artery, iv. 64, fins of fishes, bones of, iii. 845. process of the sphenoid lione, i. 255, 726. vein, i. 365; iv. 1381. 1404. dorsal, i. 36H. major, i- 3G5 ; iv. 1409. minor, or semi-azygos, i. 365 ; iv. 1409, superior, i. 366 ; iv. 1409, uvulae muscle, iii. 952. relations and uses, iii 952. B. Bahyroussa, or horned hog, teeth of the, iii. 865, Baboons, iv. \^l,ctseq. See Quadrumana. Back, Region of the (surgical anatomy;, i. .367. 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 or the, i. 368. first layer, i. 368. latissimus dorsi, i. 368. trapezius, i. 3G9. second layer, i. 370. levator anguli scapulae, i. 370. rhomboideus major, i. 370. minor, i. 37U. 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 descondens, i. 372. complexus, i. 373. longissimus dorsi, i. 372. sacro-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 c-pitis posticus major, i.373. posticus minor, i. 374. spinalis, or semi-spinalis, colli, i. 373. fasciculi : inter-spinales, iiiter-transversales,and mul- tilidus spina?, i. 374. Badgcr-txihQ (Melida?), dentition of the, iv. 913. BaUena. digestive organs of the, s. 304. Balaniidce, family of, i. 564. Bnl(e)ioptera rostrata, vocal organs and voice of, iv. 1401, 1495. Balanens nucum, or maggot of the hazel-nut, mode of locomotion of the, iii. 411. Balanidea, a genus of Cirrhopoda, i. 684. See Cirrhopoda. Ball and socket \o\wt ( Knarthrosis), i. 256. Bands, intercolumnal, i. 5. Bandicoots of Australia (Perameles), iii. 260. characters of the genus of bandicoots, iii. 260, 261. Bardbra.ox Berberines, changes in their complexion from that of their ancestors, iv. 1336, “ Barhadoes ” leg, iv. 1014. Barbary, races inhabiting, characters of the, iv, 1357. Barking oi ^ogs, 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. Bas-Jofid of the bladder, i. 379. Base of the cranium, I 725. Basidiuspores of lungi, s. 224. Basidinm, mode of reproduction of the fungi bj' the, s. 232. Basilar 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 Soemmerring, i. 726. 733. process, i. 732. of the occipital bone, i. 720. sinuses, I. 727. 732. sulci, i. 727. 732. vein, i. 216, 217. 360 ; ii. 63; 361,362 ; iv. 1407. median, iv. 1407. Basio-glossus muscle, iv. 1133. Basi~vc7'iohral veins of Brescliat, iii. 630. singing, iv. 1479. Batfnergus capensis, or white spotted orycterus, iv. 389. GENERAL INDEX. 753 Bathicrgus mariliraus, or Cape mole, anatomy of the, iv. 369, et seq. Batrachia, a class of Vertebrated Animals. See Amphi- bia. ciliary motion in, i. C28 — C30. digestive organs of, s. 301. lungs of, s. 282. effects of slightly elevated temperature on, iii. 3G. ova of, s. 51 . [91 -] structure of the ripe ovarian ovum, s. [9J.] embryonic development, s. [93.] yolk-substance, s. [93.] germinal vesicle, s. [93.] vitelline membrane, s. [9-1 ] formation of the ovum, and changes in its progress, s. [94.] pancreas of llatrachia, s. 91. pelvis of, s. 171. teeth of, iv. 885. thymus gland of, iv. 1098. thyroid gland in, iv. 1 109. tougue of, iv. 1 146. vocal organs and voice of, iv. 1502. Bats^ i. .594. See Cheiroptera. hibernation of the, ii. 764. See Hibernation. organs and mode of locomotion on land, iii. 455. pelvis of, s. 164. 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. 1 182. Bear, dentition of the, iv. 908. organs of voice of the, iv. 1489. Beaver (Castor fiber), anatomy of the, iv. .370, et scq. its mode of constructing its habitations, iii. 10, 11. digestive organs of the, s. 303. organs of voice of the, iv. 1492. urine of tlie, iv. 1280. Weberian organ in the. iv. 1419. 1428. BeeJ fat, chemical characters of, li. 233. Bees (Apidae), ii. 805. food of humble and hive-bees, ii. 865. sting of, lateral view of the, ii. 992. wings of, iii. 423. powers of H 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 bee.^, and their ac- commodation to circumst mees, iii. 19. murder of the drones on the approach of winter, iii. 20. humble (Bombus terrestris), thoracic spiracle of the, iv. 1505. .B(’e/-root, considered as an article of food, s. 395. composition of beet-root, s. 395, Beetles, li. 859. characters of, ii. 859. tribes and suu-tribes of, ii. 859, 8G0. various species of, ii. 859— 8G3. association ol the males of tloplia argentea, iii. 16. instance of mental operations in the proceedings of one, iii. 21. mode of flight of the, iii. 421. nervous system of the, iii 610. Belching, or simple eructation, s. 316. causes, s. 316. Beleynnitcs, or thunder-stones, i. 520. Belladonna^ use of, in case of muscular disturbance, iii. 721. H. Berber races, cliaracters of the, iv. 1357. Berberines. See Bardbra. 5(?roe pileus, i. 1l9; iii. 533. organs of locomotion "of, i. 38. mode of progression of, iii. 433. qviestion whether it has nervous filaments or not, iii. 602.. structure of the integuments of, s. 485. Bezoar scones, formation of, in the stomach of the chamois, iv. 85; s, 538. Biceps I'emoris muscle, iv, 61. flexor cubiti muscle, i. 216, 217. 359 ; ii, 63. 1G3. 261. 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. 163. Bicorne Uganienlum, i. 360. Bicuspid, or mitral, valve of left ventricle, ii. 583. Bile, i. 127. 374. method of analysing, iii. 811. analyses of, i. 374, 375. bile 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 witii certain normal elements of the blood, iv. 460. expulsion of the bile, iii. 180. quantity secreted, iii. 180. secretion ofbile, iii. 178. anomalous opening of the portal vein into ihe vena cava, iii. 178. effects of the suppression of the excretion of bile, ii. 150. metastasis of, iv. 462. uses of tlie 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 ofbile, iii. 195. alterations in physical properties of tlie bile, iii. 196. biliary calculi, iii. 195. entozoa, iii. 195. suppression of secretion ofbile, iii. 195. biliary congestion, iii. 187. effects 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 Gasvero- poda. in Crustacea, i. 775. Bimayies, a genus of Sanrians, 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 Aves. Bishari, mental and physical characters of the, iv. 1356. Bilch, milk of the, iii. 36:^. analysis of, iii, 362. Biventral lobe of cerebellum, iii. 689. 692. Blackbirds, their mode ot walking, iii. 451. Bladder (in anatomy generally), i, 376. Bladder uf 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. 3K7. peritoneal investment, iii. 944. membranous laminte, or tunics, of, i. 380. 1. serous or peritoneal, i. 3S0. 2 mucous, i. 380. .3. muscular, i. 380. 4. deep cellular, i. 384. organisation of the bladder, i. 386. a. arteries, i. 386. h. veins, i. 386. c. lymphatics, i 387. d. nerves, i. 387. regions of the bladder, i. 379 ; iii. 922. 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, i. 377. uvula of the bladder, i. 38-5, 386. urinary bladder in other animals, i. 377. Bladder, Urinary (abnormal anatomy), i. 389. congenital conditions, i, 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. 9-51. ectopia vesica? 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, fistulce, i. 398. fungous tumours, i. 401. hjemorrhage from ilie bladder, i. 401. liernice, i. 395. idiopathic softening, i. 399. inflammation,!. 396. introversion, i. 395. paralysis, i. 402. rupture, i. 398. sacculi or cysts, i. 393. schirrus and cancer, i. ¥-2. spasm, i. 403. varices, i. 402. symptoms of stone in the bladder, 721 H. tafiping the bladder, iii. 923. operation of lithotomy, iii. 923. 754 GENERAL INDEX. /ilapstdiP, or darkllng-bpotles, ii. 8C3. Blnps mortisaga, or darkling-heotlc, ii. 803. Blastema, iv JOO. Blaslemal formations, iv. 100. See Products, Advkn- TITIOUS. Blastoderm, germ-mass, or germinal membrane, .s. 4. Blattidee, or destructive cock-roaclies, ii. 864. Blinduess, exaltation of the sense of touch in cases of, iv. 1178. Blister-Jiies (Cantharida}), ii. 863. Blood, i. 401. arterial blood, i. 414. cliemical composition of the blood, i. 410. table ol analysis of the human blood, i. 41 1 . table of the solid and fluid parts of tlie blood, i. 412. in the human male, i. 412. female, i. 412. normal elements of, iv. 4G0. adipose matter present in the, i. 59. carbonic acid gas in the, i. 52. fibrine of the blood, ii. 258. .action of acids and alkalies upon, ii. 258. ultimate composition of fibrine, ii. 2.59. method of analysing the blood, iii. 809. the serum, iii. 810. the clot, iii. 810. coagulation, phenomena of, i. 413. means of preventing the coagulation oftlic, iv. 1G6. analysis of the cruor, crassamentum, or clot of blood, i. 413. colouring matter, heematozine or hematine, i. 411 ; ii. .503, .504. cause of the red colour, ii. -504. di.stribution of, mechanism for facilitating the, i. 223. existence of the elements of secretions in the blood, iv. 4-59. presence of urea in the blood, iv. 4.59. of uric and hippuric acid, iv. 4G0. of kreative and lactic acid, iv. 4G0. ultimate analysis of, ii. .504, globules, or blond corpuscles,!. 404 ; iii. 222. shape in different animals, i, 405. size, i. 405. structure, i. 408. table of the diameter of the globules of the blood in Mammalia. Aves, Keptilia, and Pisces, I. 407. physical qualities of the blood, i. 404. serum, i. 404. 411 . composition of serum, i. 411. transfusion, operation of, i. 409. 429. venous blood, i. 414. bile secreted from, iii. 179. 180, amount of blood conveyed to the brain, iii. 704. differences, chemical and physical, between arterial and venous blood, iv. 356. free gases in ihe l)lood, iv. 358. mutual actions of the blood and atmospheric air in respiration, iv. 3C1. causes of the change in the colour of the blood, iv. .365. analogy of milk to blood, iii. 3G2. tJalen’s doctrine of the four humours of the blood, — bills, sanguis, atra bilis, et phlegma, iv. 935. state of the, in the production of animal heat, ii. G81. Slates of the blood in the heart after death, ii. G48. phenomena of the powers moving the blood, i, 055. supply of, to the joints, i. 254. fatality attending the withdrawal of, in the lower animals, iii. 36. See also Circulation. Blood of the lower animals. See under their respective (leadings. Blood, Morbid Conditions of the, i. 415. albumen, i. 422. blastemal formations, iv. 100- See Products, Ad- VEN'j rnous. buffy coat, i. 419. coagulation, imperfect, i. 418. deficiency (anremia), i. 41G. different relations of the solid and fluid parts to one another, i. 416. .specific gravity of healthy and diseased blood, i, 416. table of specific gravities under several forms of disease, i. 417. specific gravity of the serum, i. 418. of the fibrine and red particles, i. 418. dycrasia, iv. 801. excess in quantity (plethora), i. 416. fibrine, alterations of the, i, 418. hmmorrhage, syncope from, i. 790. limmatozine, or hematine, i. 422. melanic deposit, iv. 116. chemical composition, iv. 116. alteration of ha?inatoziue, iv. 117. stagnation, iv. 117. extravasation, iv. 1 17. chemical action, iv. 1 17. oil, i. 422. parasitical animals in the blood, i. 429. polypi, i. 420. Blood, Morbid Conditions of Tm. — continved. saline constituents, in disease, i.423. Slate of the blood in inflammation, i. 423. in chlorosis, i. 428. in ciiolera, i. 428. in disease of the kidney, i. 426. in diabetes, i. 427. in fever, i. 424. in jaundice, i. 425. in scurvy, i. 425. Blood-letting, immediate and consecutive influences of, on animal heat, ii. 681. Bloodsuckers (Tabanidae), ii. 867. Blood-vessels, experiments respecting the formation of i. 51,62. of glands, ii. 487, 488. arrangement of the minute blood-vessels of glands, ii. 4S8. development of new or adventitious blood-vessels, iv. 141. under the simple mucous membrane, iii. 492, under the compound mucous membrane, iii. 493. of muscles, iii. 516. Blue -bottle fly (Musca vomitoria), pneumatic apparatus of the feet of the, iii. 443. tlioracic spiracle of the, iv. 1504. Blushing, cause of, iii. 722 Q. Boa constrictor, anatomy of the, iv. 272, el seq, its power of climbing, iii. 448. teelh of, iv. 886. Boar (Sus scrofa), anatomy of the, iii. 860. See P\- chydermata. effect of castration on the growth of the tusks of the, ii. 718. wild, the original of domesticated swine, ii. 131 1. Body of uterus, s. 625. See Uterus. Bolteniay a genus of Tunicata, iv. 1 188, et seq. characters of the genus, iv. 1 188. Bombus terrestris, or humble-bee, — thoracic spiracle of the, iv. 1505. Bombt/x mori, or silk-worm moth, its velocity in flight, iii. 423. ovum of, s. [133.] processionary, economy and mode of proceeding of the, iii. 17. Bone — Bone substance. See Osseous Tissue. Bone (general and normal anatomy), i. 430. arteries of bones, three kinds of, i. 434. 436. articular portions of, i. 247. chemical composition, i. 437. earth of bone, i. 437. component parts of, i. 437. earthy salts of bene, i. 437. in various animals, i. 437, 438. cartilage of bone, i. 437. proportion of earthy and animal matter, i. 437. lymphatics, i. 436. medulla, or marrow, of bones, i. 433. composition, i. 434. medullary membrane, i. 431. nerves of bones, i. 436. organisation of bone as part of the living system, i. 435. periosteum, i. 433. composition, i, 433. external surface, i. 433. uses, i. 433. vascularity, i. 433. physical properties and intimate structure of, in man, i. 430. colour, i. 430. elasticity, ii. 59. hardness, i. 430. shape, i. 430. specific gravity, i. 430. veins, i. 436. peculiarities in other animals, i. 4.38. Amphibia, i. 438. Aves, i. 438. Mammalia, i. 438. Bisces, i. 438. cartilaginous, i. 438. osseous, i. 438. bones of man compared with those of the lower animaB. iv. 1295—1299. In infancy, i. 69. in old age, i. 78. formation of, as passive organs of locomotion, iii. 413. See also Articulation. Bone (pathological conditions of), i. 438. diseases of the osseous system, table of, i. 439. Class T. Derangements of the internal functions, i. 439. atroi)hy, i. 443. fatty degeneration in a peculiar form of atro- phy, iv. 97. fragility, i. 441. mollities, i. 442. rickets, i. 440. Class II. Inflammation, osteitis, i. 443. adhesion, i. 444. GENERAL INDEX. 755 Bone (patliological conditions of) — coniinucd, mortification, i. 453. necrosis, i. 453. exfoliation, i. 453. scrofula, i. 454. suppuration, i. 448. syphilis, i. 450 . ulceration, i. 450. Class III. Structural diseases, i. 4-57. cancer, i. 463. bloody cellulated tumour within the bones, i. 4G4. exostosis, i. 449. 458. fungus haematodes, i. 463. enchondroma, or osteosarcoma, iv. 132 — 134. spina ventosa, i. 457. softening of the osseous framework of tlie body, iv. 712. permanent callus, or osseous tissue produced for the reparation of injuries, iv. 141. osteoma, or abnormal ossifications, iv, 1.34, accidents, i. 154. Bones in particular t — ankle-joints, i. 151. abnormal conditions of, i. 154. astragalus, i. 152 ; ii. 339. structure and development, ii. 339. basilar, i, 726. 733. of carpus, or wrist, ii. 505 ; iv. 1506. development and structure, ii. 506. of first row, ii. 505. of second row, ii. 506. clavicle, ii. 154. structure and development, ii. 156. coccyx, s. 120. of cranium, i. 725. articulations — sutures, i. 736. development, i, 741 . divisions, i. 725. surfaces, i. 737. abnormal conditions, i. 744. ciiboid, ii. 340. structure and development, ii. 341. cuneiform, of carpus, ii. 505 ; iv. 1506. of tarsus, external, ii. 341. internal, ii. .340. middle, ii. 341 . structure and development, ii. 341. of ear, ii, 546. development, ii. 560. positions, connexions, and articulations, ii, 547. of elbow-joint, ii. 65. 78. diseases of the, ii. 78. ethmoid, i. 728, 729, 730 j iil. 721, 725. of face, ii. 207. femur, ii. 165 ; iii. 44. structure and development, ii. 167. fibula, i. 151 . of fingers, ii. 507. of forearm, ii. 162— 1C4. fossil, of birds, i. 289. See Aves. frontal, in Carnivora, ii. 473. frontal, i. 728 ; iii. 725. of hand, ii, 505. of heel, ii. 339. huckle-bone. See Coccyr, humerus, i. 216 ; ii. 63. 66. 159 ; iv. 573. injuries to the, i. 362 ; ii. 69. structure and development, ii. IGi. hyoid, iii. 105; iv. 1123. incisive, or intermaxillary, ii. 210. incus, or anvil-bone, ii. 546. development, ii. 560. innominate, s. 114. intermaxillary, ii. 210. of knee-joint, iii. 44. lachrymal, ii- 212. structure and development, ii. 212. lenticular, ii. 547. lunar, of carpus, i. 240 ; ii. 505. malar, i. 728, 729 ; ii. 211. structure and development, ii. 212. malleus, or hammer hone, ii. 546. development, ii. 5G0. maxillary, inferior, ii. 213. structure and development, ii. 213. superior, i. 728, 729 ; ii. 207. structure and development, ii. 209. metacarpus, ii. 507. first, second, third, fourth, and fifth, ii. .507. structure and development, ii, 507. metatarsus, ii, 341. first, second, third, fourth, and fifth, ii. 342. structure and development, ii. 342. nasal, i. 729; ii. 210. 212 ; iii. 723, structure and development, ii. 212 ; iii. 724. navicular, of carpus, ii. 505, occipital, i. 726, 731. basilar, process of, i. 726. development, j. 731. os occipitis. i. 367. os basilare, i. 726. 733. Bones in particular — continued. os calcis, or heel-bone, ii. 339. structure and development, ii. 341. os epactate, or triangular, i. 744. os frontis, i. 728. os hyoides, iii. 105. os lenticulare, ii. 547. os magnum, ii. 506. os occipitis, j. 731. os parietale, i. 735. os planum, i. 731. os sphero-occipitalo, i. 733. os temporum, i. 733. os unguis, i. 729. ossicles, or small bones of ear, ii. 546. development, ii. 560, positions, connexions, and articulations, ii. 547. palate, ii. 210. development, ii. 21 1 . palatine, i. 728 ; li. 210. parietal, i. 735. angles, i. 736. borders, i. 736. connexions, i. 736. development, i. 735. surfaces, external and internal, i. 735. patella, or knee-pan, ii. 168; iii. 45. structure and development, ii. 168. pelvis. See Pelvis. phalanges of fingers, ii. 507. structure and development, ii. 507. of toes, ii. 342. structure and development, ii. 342. pisiform, ii. 505 ; iv. 1123. radius, i. 249; ii. 65—67, 163; iv. 228, 229, 1505. structure and development, ii. 164. tubercle of the, ii. 66. ribs, iv. 1024. sacrum, i. 367; s. 120. scaphoid of carpus, i. 249; ii. 505 ; iv. 1506. of tarsus, ii. 340, 343. structure and development, ii. 341. scapula, ii. 156; iv. 4.37. structure and development, ii. 157. 159. semilunar, or lunar, of carpus, ii. 505 ; iv. 1506. sesamoid, iv. 541. spheno-occipital, i. 733. sphenoid, i. 726. 728; iii. 725. azygos process of, i. 255. stapes, or stirrup-bone, ii. 547, 548. sternum, iv. 1022. of tarsus, ii. 339. anterior and posterior row of, ii. 339. motion of the tarsal joints, ii. 344. structure and development, ii. 311. temporal, i. 733. connexions, i, 735. development, i. 735. mastoid portion, i. 734. petrous portion, i. 733. squamous portion, i. 734. of temporo*maxillary, iv. 937. tibia, i. 151 ; ii, 1G8; iii. 45. structure and development, iii. 170, 171. of toes, ii. 342. phalanges, ii. 342. See Phalanges. trapezium, ii. 506. trapezoid, ii. 506. turbinated, inferior, ii. 213: iii. 725. structure and development, ii, 213 ; iii. 725. middle, iii. 721. superior, iii. 724. ulna, i. 249 ; ii. 65, 66. 164. fractures of, ii. 69. structure and development, ii. 163, 164. unciform, ii. 506. vomer, or ploughshare, ii. 213 ; iii. 725. structure and development, ii. 213. whistle-bone. See Coccyx, of wrist-joint, iv, 1506. Bone-caves ofWellington Valle}', Australia, iii. 259, note. Boring flies, ii. 865. Bos^ vocal organs and voice of, iv. 1494. Bostricidi/n/ucd. cranium, temporal bones, i. 473. forearm, i. 476. humerus, i- 476. metacarpal bones, i. 476. ribs, i. 475. sacrum, i. 475. shoulder, i. 475. acromion process, i. 476. clavicle, i. 476. coracoid process, i. 476. scapula, i. 475. sternum, i. 475. vertebral column, i. l74. cervical vertebrte, i. 47 1. coccygeal, i. 475. dorsal, i. 475. lumbar, i. 475. posterior extremity, i. 476. femur, i. 476. metatarsal bones, i. 477. pelvis, i. 476. tibia and fibula, i. 476. toes, i. 477. secretions, i. 481 . follicles producing peculiar secretions, i. 481, 482. urine, i. 4S1. Carotid nerve, ii, 555 ; iii. 887. Cakotid 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. 93. anterior branches, i. 485. 1. thyroid, superior, i. 485. branches, i. 48‘>. a. hyoidean branch, i. 485. b. superficial, i. 485. c. laryngeal, i. 485 ; iii. IIO. 2. lingual, i. 485. branches, i, 485. a. hyoidean, i. 486. b. dorsalis Unguis, i. 486. c. sublingual, i. 486. d. ranine, i. 486. 3. labial, or facial, i. 486. branches, i. 486. a. inferior palatine, i. 486. b. submental, i. 486. c. inferior labial coronary, i. 486. 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 ihe 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 auricularis 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 meningeal, i. 489. b. inferior maxillary or inferior dental, i. 489. c. posterior deep temporal, i.489. d. masseteric, i. 439. c. pterygoid arteries, i. 489. /. buccal artery, i. 489. g. anterior deep temporal, i. 489. h. alveolar, i, 490- i. infra-orbital, i. 490. l. superior palatine, i. 490. m. Vidian, i. 490. n. pterygo-palatine or superior pharyngeal, i. 490. 0. 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, ophtlialmic branches — continued. 4. ciliary arteries, i. 491. anterior, i. 492. hmg, i. 491. short, i. 491. 5. muscular arteries, i. 492. inferior, i. 492. superior, i. 492. 6. posterior ethmoidal artery, i. 492. anterior ethmoidal, i. 492. 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 of 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. 496. Carotid canal, i. 734 foramen, i. 734. branch of Vidian nerve, ii. 288. plexus of nerves, internal, s. 426. external, s. 426. Carpi teeth of, iii. 979. Carpal arteries, iv. 1506. articulations. See Carpus. branch of radial artery, ii. 529. Carpi radialis artery, anterior, iv. 223. dorsalis, iv. 223. ulnaris posterior, iv. 225. anterior, iv. 225. Carpo-mctacarpal ligaments of thumb, ii. 509. dorsal, ii. 509. palmar, ii. 509. articulations, ii. 509. joints, motions of the, ii. 509. of the thumb, ii. 509. Carpopkaga, 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. 360. Carrots, composition of, s. 395. considered as an article of food, s. 395. Cartilage of bone. i. 437. See Bone, Normal Anato.my. Cartilage, i. 495. chemical composition, i. 498. elasticity of, ii. 58. divisions, i. 495. A. temporary, i. 405. 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, ]. 243. II. non-articular, i. 496. differences depending upon age, i. 496. elasticity, i. 496. structure, i. 496. organisation, i. 496. physical properties, i 406. 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 condition.*;, i. 499. inflammation, i. 499. ulceration, i. 429, 500. See also Joint. primary, i. 499. secondary, i. 499, 500. 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. GENERAL INDEX. 700 Cartilage — continued. ensiform, or xiphoid appendix, iv. 1023. ossification of tlie, iv. 1024. fibro-triangular, iv. ITiOG. fil>rous and spongy, adventitious, formation of, iv. 142. of hip-joint, inflammation and ulceration of the, ii. 788. intervertebral . i. 250. of knee-joint, iii, 45. of larynx, iii. 100. diseased conditions of the, iii. 120. See Larynx, morbid anatomy and pathology, loose, iv. 538. of the nose, iii. 72G. superior, iii. 726. lateral, iii. 726. triangular, iii. 72G. inferior or pinnal, iii. 72G. structure, iii. 727. of the ribs, i. 249. sacro-iliac, s. 122. of Santorini, iii. 102, semilunar of knee-joint (cartilagines falcata^ s. lu- nata'), iii. 45. sesamoid, iii. 727. softening of, iv. 712. tarsal, iii. 78. 81 . ciliary, iii. 81. orbital, iii. 81 . thyroid, iii. 101. of tibio-flbular articulations, iv. 1119. triangular of wrist-joint, i. 249. Cartilaginous deposits m the diaphragm, ii. G. fibro-cartilaginous tissue, i. 127. patclies in the coats of arteries, iv. 87. rings of the trachea, s. 2GI. tissue, elements of the, i. 127. Cartilaginous fishes. See Pisces. Caruncula lachrymalis, iii. 80. 81. calculi in tlie follicles of the, iv. 82. seminalis, iv. 1252. See Caput gallinaginis. Carunculcc myrtiformes, s. 711. Caii/bdca marsupialis, organs of digestion of, i. 43. Cnruophyllia 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. 1(?2. ]>ropo»tion of, in various kinds of milk, iv. 168. mode of oblaining 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, ct scq. organs of voice of tlie, iv. 1 192. C a. y or rum., secretion of the drug, iv. 396. Castration, ii. 443. effects of. in the female, ii. 443. in the male, ii. 443. circumstances analogous in hermaphroditism, ii. 413. 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 lime 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. 085. 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 the, i. 255. organs of voice of the, iv. 1490. powers oi leaping of the. iii. 474. its love of the odour of Nepeta (cat-mint) and Vale- rian, iv. 702. Cat, flying, mode of flight of the, iii. 430. Catalytic tiQi\ox\ 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. 399. “ Catarrh of the dying,” i. 80i. Catarrhus uteri, s. 694. CaterpUlarSy dormant vitality of, iii. 1.57. See Insecta, larva of, Catodontidar, family of, i. 564, Caucasian race, iv. 1328. principal characters of the, iv. 1348. capacity of skull of the, iii. 666. Cauda, or exti emity, 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 nf■rve-^ esides, iii. 647. Caulifiower excrescence of the uterus, s. 700. Cava 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. MOL cobaya, Weberian organ in,iv. 1418. Cavia., or Guinea-pig, anatomy of the, iv. 372, et scq. paca (the paca), anatomy of the, iv. 372, et scq, Cdvicormia, anatmny of, s. 50S. horns of, s. 518. Cavities of the face, ii. 217. See Nose; Orbit. Cavity, in general, i. 500. definition, i. 500. abdominal cavity in particular, i, 500. epigastric region, i. 502. hyposastric region, i. 505. umbilical region, i. 504. abnormal conditions of the abdominal cavity, i. 507. congenital malformations of the abdominal pa- ncles, i. 508. morbid conditions of the abdominal parietes, i. 509, 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, Hi. 674. or fossa trochanterica, ii. 166. glenoid, i. 219. 735; ii. 340; iv. 573. of radius, ii. 163. of scapula, ii. 157. of tibia, external, ii. 168. internal, ii. 168. nasal, iii. 723, 724. of the pelvis, s. 127. peritoneal, iii. 910. sigmoid, greater, ii. G6. 162. lesser, ii. 66. of the ulna, iv. 229. Cavity, thoracic. See Thorax. of tlie tympanum, ii. 543. 546 of the uterus, s. 627. See Uteo-us. Cavum sen sinus laryngis. See Itima glottidis. Cavy of Patagonia (Chloromys Patagonica;, anatomy ot the, iv. 384, et scq. Cchina, or monkeys of the NewWorUl. iv. 210, et seq. a genus of Quadrumana , iv. 210, irr/. See Qua- DRUMANA. characters of the genus, iv. 210. Ceciliadce, a family of Reptilia, iv. 265, etseq. Cc/Levolution. See Adventitious Products, — blastemal formations. Cc/Z-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. Cellula ethmoidales, i. 731. Cellular, deep, membranous laminai of the urinary bladder, i. 384. Cellular Tissue, i. 500. arrangement, i. 509. common cellular membrane, i. 510. penetrating, i, 510. special, i. 510. development, i. 512. propnrties, i. 511. theories, i. 511. structure and organisation, i. 511. bloodvessels and lymphatics, i. 511. chemical composition, i. 511. nerves, i. 51 1. morbid conditions of cellular tissue, i. 513. I. inflammation, i. 513. a, acute circumscribed inflammation, or phlegm mon, i. 513. 1 . congestion of the bloodvessels, i. 513. 2. effusion, i. 513. 3. suppuration, i. 514. 4. ulceration, i. 614. 5. mortification, i. 514. h. 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, i. 516 ; ii. 333 ; iv,712. softening, iv. 712. IV. morbid growths, i. 516. V. foreign bodies, i. 516. See Adipose 7’issue ; 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. GExNERAL INDEX. 761 Celtic races, principal characters of the, iv. 1348. Cejnent of teeth (c^mentum, crusta petrosa), iv. 864, 865. Cenan^ium frangulae, ripe spores of, s. 227, 228. Cent:pedes, xW.hAb. nervous system of the, iii. 609. luminousness of some, iii. 198. Central 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 Vieussens), iii. 674 604. minus, iii. 674. fibres of the centrum ovale, iii. 723 B. tendineum, s. uerveum, s. phrenicum, ii. 2. Cephalic or radial vein, i. 216. 359, 360; ii. 63 ; iii. 249 ; iv. 1407. median cephalic, ii. 361, 302 ; iv. 1407. Cephalo-pharyngeal aponeurosis, iii. 945. Cephalopoda (a class of Iiivertebrata), i. 114- 517. characters of the class, i. 114. 517. arms, i. 517. branchi^, 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 otRcinalis, s. [105.] spermatozoa in Cephalopoda, iv. 4:^5. 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. 551 ; 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. Ceralo-glossus muscle, iv. 1133. Ceratohyal process, iv. 1 124. Cercarice, seminal, ii. 112. See Entozoa. mode of reproduction of, s. 30. vegetable, ii. 112. Cercopitkecus, a genus of Quadrumana, iv. 196, et seq. See Quadrumana. characters of the genus, iv. 196. Cerealia^ the, considered as food, s. 393. constituents, s. 393. bread, s. 393. Cerebellar arteries, inferior, iii. 704 ; iv. 821. posterior, iii. 704, 70.5. superior, iii. 704; iv. 821. fibres, or restiform bodies, of the medulla oblongata, iii. 683. 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. 6'Jl. corpus dentatum, or rhomb. »ideum, iii. 692. crus cerebelli, iii. 674. 677. 685. 692. peduncles of, iii. 693. inferior, ii. 272 ; iii. 693. middle, iii. 603. superior, — processus cerebelli ad tostes, 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. 732 ; iii. 687. horizontal, iii. 688. purse-like fissures, or posterior notch, iii. 688, semilunar, iii. 687. valley, iii. 687. laminge, 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. Sapp. Cerebellum, lobes — conlimicd. 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. 689 691. superior, iii. 689, 690. 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, 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, lunctions of the, iii. 722 X. fissure, great, of Bichat (transverse or horizontal of Cruveilhier), iii. 673. ophthalmic vein, iii. 94. sinuses, iv. 1374. or superior surface of the cranium, i. 733. veins, nerves of, iv. 1382. Ccrehric acid, iii. 587. Cerebrine, in the composition of the blood, i. 411. Cerebro-cerebellar commissures, or processus cerebelli ad testes, iii. 693. Cerebrospinal centre, iii. 650- See Cerehellmn ; Cere- brum; Encephalon ; Medulla oh\ong-^id>. \ MesocephalCi Spinal Q.oxd \ Nervous Cenires, Cerebrospinal &kx\6., 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. 693. nerves, connection bslween 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 7G2 GENEKAL INDEX. Cervical — continued. lynipliatic plaiuls, i. 3GS. liiiea alba, ii. 230. Cervical nerves, ii. 272. superior, ii. 272. posterior roots of, ii. 272. nerve, anterior, iii. r>71. descending, internal, iv. 753. first, posterior branch, iv. 707. 74S. 750. anterior brancli, iv. 752. second, posterior branch, iv. 750. anterior branch, iv. 752. superficial (supcrlicialis colli), origin of, iv. 753. ascending branch, iv. 753. descending branch, iv.753. third, anterior branch, iv. 752. posterior branch, iv. 751. ascending branch, iv. 751. descending br.mch, iv. 752. horizontal branch, iv. 751. fourth, anterior branch, iv. 752. anterior branches of the four inferior, iv. 754. l)Osterior root of, iv. 751. fifth, sixth, seventh, and eighth posterior branches, iv. 751. plexuses of nerves, i. 3G8. 748 ; ii. 555. posterior, iv. 751. Cjrvicul vertebra3 of Carnivora, i. 474. See Caiinivora. Ce.rvico-Jacial nerve, iii. 904. Cervicu-lhoracic septum, iii. 570. CcrvidcCy a sub-order of l^Iammalian quadrupeds, s. 508. anatomical characters of, s. 508, et scq. vocal organs and voice of the, iv. 1491. Cervix. See Neck. Cervix of the bladder, i. 387. Cervix of uterus, s. 625. structure and arrangement of the tissues composing the cervix, s. 038. muscular coat, s. G38. mucous coat; epithelium, s. 638. papillae, s. G39. mucous follicles, s. 640. arteries which supjily the cervix, s. 6-11. alterations in the form of the cervix during gestation, s. 615. 640. pathological conditions of the. See TJlerus. Cervus Muntjac (the kijang or muntjak), s. 508. cranium of, s. 512. Ccsloidca,cin order of Entozoa of Rudolphi, ii. IIG. See Entozoa ; Stcrelmintha. digestive organs of the, s. 295. ova of Ccsioidea, s. [121.] Cetacea (a class of Mammiferous Vertebrate Animals), i. 502. bones of the, i. 438. circulation, organs of, i. 576. digestion, organs of, i. 571 ; s. 301. divisions, i. 563. generation, organs of, i. 591. male, i. 691. female, i. .592. motion, organs of, i. 5G4. nervous system, i. 582. organ of sight, i. 581. 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. CetinCy chemical comi»ositiou of, ii. 234. CetoniidcCy ii. 859. Ceylon. Albinoes of, i. 84. Chacrelas. or Albino, i. 86. Chixtodon rostratus, its mode of taking its prey, iii. 8. ChcnlonotuSy a genus of Rotifera, iv. 401, ct seq. ChnJfer-h&Qi\es (Melolonthida?), ii. 860. Chalnxce of fowls’ eggs, s. 64. Chalky elTect of large doses of, in producing intestinal cal- culi. iv. 84. ChamcEleo7iidcVyB. family of Reptilia, iv. 265, 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, ChamoiSy formation of Bezoar stones in the stomach of tlie, s. .538. Chancre, co-existence of, with gonorrhoea, iv. 1258. incipient, treatment of, by lunar caustic, iv. 803. Charay germination of, s. 222. CharacccUy reproductive organs and mode of reproduction of, s. 222. Charactcfy individual ; share which the emotions take in the formation and development of, iii. 722 R. Charruan Indian, portrait of, iv. 1358. Cheeks (buccte), iii. 950. muscles, vessels, and nerves, iii. 950. use of the cheeks, iii 950. Chccscy chemical properties of, ii. 18 ; iii. 359 ; s. 392. considered as an article of food, s. 302. Ckeiro^leuSy a genus of Quadrmnana, iv. 21 5, et scq. See Quadrumana. characters of the genus, iv. 215. Cheiromys psilodactylus (aye-aye of Madagascar), iv. 221. anatomy of the, iv. 374, et seq. Cheiroptera (an order of Mammiferous Vertebrate Ani- mals), i. 694. characters by which the order is distinguished, i. 595. definition, i, 594. digestive organs, i. 599 ; s. 302, generation, organs of, ir 000. female, i. 600. male, i. COO. organs and mode of locomotion on land, iii. 455, wings and powers of flight of the, iii. 430. organs of the senses, i. 698. of hearing, i. 598. 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. 1005. Chcloniay an order of Reptilia, iv. 265, cl 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. 1 147. vocal organs of the, iv. 1502. Chclyosoma, a genus of Tunicata, iv. 1188, etseq. characters of the genus, v. 1 188. Ch'Viical rays of light, iv. 1437. Chemistry y organic and inorganic, similarity of the com- pounds supplied by each, i, 118. 124 ; iii. 152. ChcDiosis 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. cliiusma in Invertebrata, iii. 769. in Osseous Fish, iii. 7o9. in Cartilaginous Fish, iii. 7G9. in Birds, iii. 769. in Amphibia and Reptiles, iii. 769. in Mammalia and Man, iii. 7G9. use of the chiasma, iii. 771. C///c/rc«- breast, iv. 1039. Chills, influence of, on the state of general health, ii. C60. Chilodon ornatus, iv. 14, 15. Chilognathay an order of Myriapoda, iii. 545. characters of the order, iii. 545. Chilopoda, an order of Myriapoda, iii. 54G, et seq. characters of the order, iii. 546. Chinmey-sweeper's cancer, or cancer scroti, iv, 1014. Chimpanxee (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. 155. organs of voice of the, iv. 1487. Chinchillay anatomy of the, iv. 373, et seq. Chinese y cranium of, iv, 1325. women’s feet, ii. 346. language, method by which the relation between tlie dillerent 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. ChilinCy or entomoline, ii. 881. chemical composition of, ii. 882. Ch'ton niarmoratus, nervous system of the, iii. 606. ChlatJiypho7’us truncatus, description of the, ii. 53. 55. Chloride of gelatin, ii. 405. ChlorinCy action of, on protein, iv. 163, 164. Chloruformy effect of the inhalation of, iv. 697. 1182. Chloromys Patagonica, or cavy of Patagonia, anatomy of the, iv. 384, et seq. Chloroproteic acid, iv. 163, 164. Chloi'osis, state of the blood in, i. 428. Choci'oputamidcCy anatomy of the, iii. 859. See Pachyder- mata. Chceropusy a genus of Marsupialia, iii. 261, ci seq. CholclithSy 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. Cholesteoiomay iv. 98, in tumours, iv. 98, granules, iv, 98. patches, iv, 98. scales, iv. 98. CholesterinCy or cholestearine, in gall-stones, i. 376. components of, i. 376. in the composition ofthe blood, i. 410; iv. 4G0. general index. 703 C/iulcsterine — continued. ill the brain, iii. 587, 588. found in various morbid growths, iv. 98. method of determining the presence of, in organic sub- stances, iii. 796. 805. quantitative analysis of, iii. 798. Chondro-glossus muscle, iv. 1133. Chondro- or coito-xiphoid ligament, iv. 1033. Chondro.sternnl articulation, iv. 1032. Chondroptcrygii, a division of Fishes, iii. 956, et scq. characters of the division, iii. 956. Chorda tympani nerve, ii. 296. 5-19. 554 ; iv. 546. motor function of the chorda tympani, iv. 553. canal of, li. 556. Chordee tendinte, ii. 681. 583. 601. Chordie vocales, iii. 102. 105. inferior and superior, iii. 105. destruction of ihej by ulceration, iii. 119. morbid appearances, iii. 119. Chordee 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. Chorion, or external covering of ovum, ii. 453 ; s.3. 716. See Generation i Ovum 3 Uterus and its Appen- dages. production of, in insects, s. [113. J development of the, s. [84.] Chorion of palpebral conjunctiva, iii. 85. Choroid arteries, i. 492 ; iii. 704. coat or membrane, ii. 178, 179. corpus ciliare, ciliary processes, ii. ISO. orbiculus s. circulus ciliaris, — ciliaiy circle, ii. 180. piginentum 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. G93. plexuses of the lateral cerebral ventricles, iii, 634. crystalline formations in the choroid plexuses, iii. 635. deposit of lymph in the, iii. 720 F. eartliy concretions in the, iii. 720 F. vesicles in, formerly regarded as hydatids, iii. 720 F. Choroid gland, or muscle, in fishes, ii. 205. Chousi7iga, cranium of the, s. 519. Chromatic aberration of light, iv. 1438. 1441. Chromato-dijopsis. See Achromatopsy ; Vision. Chromato-metablepsis. See Achruinatopsy i Vision. Chromato-pseudopsis. See Ackroyyiatopsy i Vision. I hromato-pseudopsy. See Achromatopsy ^ Vision. Chrysalis form of insects, ii.879. Chrysididcc, or golden wasps, ii. 866. habits of the. ii. 866. Chyle, i. 29. 600, 601 3 iii. 222. formation of, s. 355. 398. analysis of chyle, i. 29 3 il. 19, 20 ; iii. 222. chemical and physical properties of, ii. 19 3 iii. 715. process of chylification, ii. 19. taken from the thoracic duct, iii. 252. before reaching the thoracic duct, iii. 223. animalisation of, i. 29. sanguification of, i. 35. chyle globules, iii. 221, 222. chyle grannies, iii. 221. motion of, hi. 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. Chyliferous System (in comparative anatomy), i. 600. in Amphibia, i. 601. See Amphibia. in Aves, i. 601. See Aves. in Mammalia, i. 601. See Mammalia. in Pisces, i. 601. See Pisces. in Reptilia, i. 601. See Reftilia. Chyliferous vessels, i. 601. See Chyliferous System. Chyme, i. 601 3 s. 335. description of, i. 293 s. 398. analysis of, i. 29. properties of, ii. 16. process of chymification, ii. 16. See Digestion. Cicada h$matodes, or tree-hopper, ii. 868, vocal organs of the, iv. 1503. CicadidcB, or tree-hoppers, ii. 868. Cicairicula, or embryo-spot of ovum, ii. 452 ; s 68. 70. 73. See Generation 3 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. campestris, i. 111. Cicindelitlce, ii. 860. Cigalce, 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 Ac;dephas, i 613. 5. in Actinia, i. 614. 6. in Echinodermaia, i. 614. uses, i. 616, 617. 7. in Annelida, i. 617. 8. in Mollusca, i. 619. A. Gasteropodous Mollusca, i. 619. a, Nudibranchiata, i. 619. h. Cyclobranch iata, i. 620. c. Pectinibranchiata, i. G2O. d. Pulmonifera, i. 621. P. Conebiferous Acephala, i.G2l, 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. 032. a. surface of the body, i, 632. h. respiratory system, i. 632. c. alimentary system, i, 632. d, rejiroductive 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 thecilia have no real existence, i. 636. 1 1. of the motion caused in fluids by the cilia, i. 636. summary, i. 636. Cilia. See Eyelashes; Eyelids. Cilia of animalcules, iv. 6. CV/mry 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 ox lenticular ganglion, ii. 281 ; iii. 785; iv. 622. Ciliary motion, i. 606. See Cilia. ol the lubuli 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. Ciliohrachiaia, digestive organs of the, s. 297. mode of reproduction of the, s. 22. C///og?‘rtrfa(Acalephae), i. 36. Ciliograde animals, mode of progression of, iii. 432. Cinerca gelatinosa, substantia, iii. 653. abdominis 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. 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. 612. Reptiles, i. 96. 643. portal circulation in, i. 646. Fishes, i. 646. portal circulation of, i. 647. in invertebrated Animals, i. 648. Acalephae, i. 6 >4. Annelida, i. 650. arenicola, or sandworm, i. 650. erpobdella, or leech, i, 651. lumbricus, or earthworm, i.G50. naides, i. 650. 3 D 2 '(64- GENERAL INDEX. C'lKCULATiON. Invertebrati'd .-Viiiinals, .\iinelida— ca;(((rt«rd. Arachnida, i, 652. Articulata, i. 650. Crustacea, i. 652. • Entozoa, i. 654. Inlusoria, i. 654. Inst’Cta, i. 651. Mollusca, i. 648. Polypi, i. 654. See also Cilia. Zoophytes, i. 65!i. Pchinoderniatn, i. 653. Planai ia, i. 6.53. III. phenomena of tlie circulation and powers moving the blood, i. 655. 1. n<)\v of the blood tlirough the heart, i. 65.5. 2. phenomena of the arterial circulation, i. 658 a. velocity of the blood in dillerent arteries, 1. 6.59. b. force ol the blood in the arteries and force of the heart, i. 661. r. arterial pulse, i. 663. rf. vital properties ofthe arteries, i. 661. c. influence of the vital powers of the arteries on the circulation, i. 067. 3. phenomena of capillary circulation, i. 669. a. structure and distribution of the capillary vessels, i. 669. b. properties of the capillary vessels, i. 6^19. 4. phenomena of the venous circulation, i. 674. IV. relation of the circulation to other functions, i, C75, 1 . to respiration, i. 675. 2. cii dilation within the cranium, i. 678. 3. influence of varie'ies 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 tlie di'Covery of the circulation, i. 681. Circu/atwn in the brain, iii. 704. arterial, iii. 704. venoU', 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 dr*ath. i. 801. disorders of the venous circulation of the live'-, i. 183. condition of the, during the sleep of iiiberuating ani- mals, ii. 771. animal and vegetable circulation compared, i. 1.33. circulation in comparative anatomy. See under the various headings. Circulus articuli vasculosus, i. 254. tonsillaris, ii. 497. C/rcumcision of females in Arabia, ii. 686. Cn'cnmduction^ a motion of joints, i. 256. Circuwjlex artery, external femoral, ii. 246. 770. a. ascending branch, ii. 246, b. descending branch, ii. 246. c. circumflex branch, ii. 247. internal, ii. 247. of scapula, iv. 436. poster) r, iv. 436. iiiac, 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. Circumflexus palati muscle, iii. 951. relations and action, iii. 951. scapulse artery, i. 364. Circumvallate papilla? of tongue, iv. 860. 1 122. CiURHOPODA (a class of Invertebrate Animals), i. 1 10. 683. characters of the class, i. 683. circulation, organs of, i. 689. deflnition, i. 6^3. division of the class, i. 681. external coverings and organs of support, i. 684. locomotion, organs of, i. 6K7 mortality and sensation, i. G88 ; 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 (Acalephae), i. 36. organs of digestion in, i. 41. food of, i. 43. locomotive powers of the, iii. 433. Cirripeda, characters of the class, i. 245. 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 Tunicaia, iv. 1188, et seq. characters of the genus, iv. 1188. ClavellinidiB y iamWy of Tunicata, iv. 1188, scq. characters of the family, iv. 1188. genera of, iv. 1 188. Clavicle, or collar-bone, ii. 154. development, ii. 156. structure, ii. 166. Clavicular extremity of sternum, iv. 1023. fascia, i. 360. nerves, iv. 753. Claws, structure of, s. 477. (7/fc/r-beetle (Elater noctilucus), ii. 861. 6Vr;;zu/e, influence of, in the production of animal heat ii (i70. effect of, on animal luminousness, iii. 199. constancy of the relation between climate and tlie 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 Fteropoda, iv. 171. integument of, iv. 171. muscular system, iv. 172. locomotive apparatus, iv. 173. respiration and circulation, iv. 173. nervous system, iv. 173. eyes, iv. 174. head-cowls and tentacnla, iv. 174. conical appendages to the head, Iv. 175. mouth, iv. 176. dental apparatus, iv. 176. generative system, iv. 177. Clio borealis, i. 113. Clitoris, s. 709. blood-vessels of. s. 709. 713. crura, glans, and prepuce of, s. 138. 709. ligaments and muscles of, s. 709. nerves of, s. 709. development, s. 710. high degree of sensibility of the, ii. 417. functions of, analogous to tliose 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. 686, 687, amputation of the, in Arabia and Egypt, ii.686. Chsterinidcc, a family of Polygnstric animals, iv. 4, et scq. Closterium, mode of reproduction of, s. 219. Clot ol blood, analysis of, i. 415. its importance in a curative point of view, i, 419. Clolhes-mQi\\s (Tineidee), ii. 867. Club-ioot, anatomical characters of varieties of, ii. 348. causes of, iii. 132. plan of opera'ion for cure of, iii. 132. treatment for union ofthe tendon, iii. 132. Clv-hiona claustraria, development of spermatozoa in, iv. 490, 491. Clupea harengus, or herring, eyes of, iii. 1002. tongue ofthe, iv. U4G. Clupeidce, a family of fishes, iii. 957. Coagulation of blood, phenomena of, i. 413. analysis of the crassamentum, i. 413. bufly coat, causes of, i. 414. iinjiortance of the clot in a curative point of view, i. 419. Coats, or tunics, of Fallopian lube, 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 ick, iii. 448. Cowper's gland, ii. 422. in man and in other animals, ii. 422. Coccidce, ii. 868. Coccine, or animal matter of cochineal, ii. 881. Coccinclla, or lady-cow, ii. 863. Coccygean branch of ischiatic artery, ii. 834. vertebrae of Carnivora, i. -174. bee Carnivora. Coccygeo-anal muscle, i. 176- Cuccoons, ii. 876. See Insecta — larva. Coccyx, ii. 500; s. 120. base, s. 120. apex, surfaces, and borders, s. 120. development of the coccyx, s. 121. tuberosities ofthe, s. 127. the coccyx in infancy, iii. 920. ankylosis of the coccyx, s. 207. cause of pelvic obstruction and protracted labour, s. 207. fractures of the, s. 209. Cochineal insect, fat of, ii. 235. Cochlea, ii. 531. aqueduct of, i. 734 ; ii. 532. axis columella, or modiolus, ii. 531. canalis spiralis cochlea?, ii. 531. lamina gyrorum, or tube of cochlea, ii. 532. lamina spiralis of, ii. 532. scales of, tympanic and vestibular, ii 532. GENERAL INDEX. 765 Cochlea — continued. nervous fibrils of the, ii. 541. development and abnormal conditions of the. ii. 557. office of the, in the function of hearing, li. 5G8. 577- Cochlear artery, ii. 542. Cochleai'iform process, i. 734 j ii. 544. Cock (Gallus domesticus), spermatozoa of the, iv. 478, 479. Cockchafer^ associations of males during the pairing season, iii. 16. Cockle^ nervous system of the, iii. 604. Cuck^roaches. destructive (Blattids), ii. 864. Cod-Jish (Gadus morrhua), brain and cerebral nerves of the, iii. 995. causes of its migration to the coast northward, iii. 13. form of, considered with respect to its mode and organs of progression, iii. 437. Ccecal foramen, of frontal bone, i. 729, 730. Ccelelmintha, ii. 111. digestive organs of the, s. 296. muscular and nervous system of the, iii. 535. Cecliac axis, or cceliac artery, i. 189. 194 ; s. 325, Cceliac, solar, or epigastric, plexus of nerves, s. 428. Ccendou, anatomy of the, iv. 372, et seq. Ccenurus, a genus of cystic Entozoa, li. 118, Coffee^ considered as an article of food, ii. 14 ; s. 396. chemical constituents of, s. 396. effects of coffee on the system, s. 396. “ Coffin‘\}ox\e ” of the horse, iv. 719. Coheision of germs, cases of, ii. 317. Cohesive strength, iii. 415. CWrf, its peculiar infiuence upon the spinal cord, iii. 21 H. ice applied to the spine in cases of muscular disturb- ance, iii. 721 H. effects of, on animal heat, ii. 660. G75. 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. Co/rf-blooded animals, temperature of, as compared with warm-blooded animals. See Heat, Animal. Colds in the nose, iii. 738. See Nose. Coleoptera^ an order of Insecta, ii. 859. characters of the order, ii. 859. tribes and sub-tribes of, ii. 859, 860. various species of, ii. 859 — 863, nervous system of the, iii. 610. wings and powers of flight of, iii. 421. ColepinidcE (box animalcules), a family of Polygastric animals, iv. 4. characters of the family, iv. 4. Coleps, 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 urethrae, iv. 1248. seminalis, iv. 1252. See gallinaginis. Colliers, peculiar disease of the lungs to which they are liable, iv. 117. Colliquamentum of the ova of Arachnidans, i. 213. Colloid, i. 694. Colloid cancer, characters of, iv. 137. of the testicle, iv. 1010. Culloma, iv. 135. Colloi'edo, Lazarus, the heteradelph, iv. 969. Cullum, See Neck. Colobus, a genus of Quadrumana, iv. 196, ct 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. 914 ; s. 365. sigmoid flexure, iii. 944 ; s. 365. appendices epiploicee, s. 366. movements of the large intestine, s. 3GG. mucous membrane of the colon, s. 368. development of the colon, s. 402. uses of, in digestion, ii. lu. Colostrmn, 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. Colpodeadcc (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. Culumba (pigeon), nervous system of the, iii. 622. Columella cochleae, ii. 631. Columna nasi, iii. 726. ColumncB carneae, teretes lacerti, ii. 581. loraminis ovalis, ii. 580. rugarum of vagina, s. 706. Columns of medulla oblongata, anterior pyramidal, iii. 679. Columns of mt dulla oblongata — continued. olivary, iii. 679, 083, 684. posterior pyramidal, iii. 679. 6s3, 634. resliform, iii. 678, 079 — 'i82. 684. of the rectum, iii. 921. of the spinal cord, functions of the, iii. 721 N. office of the aniero-lateral columns, iii. 721 O. of the posterior columns, iii. 721 O. manner in which the posterior columns may contribute to the exercise of the locomotive functions, iii. 72l 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, alimentary canal of, s. 297. muscles of the, iii. 537. Combustibles \ised.\\\ organic analysis, iii. 814. Combustion, hypothesis of, as the physical cause of animal hf-at, ii. 684. Combustion apparatus of Liebig for organic analysis, iii. 814. Commissural nervous fibres, iii. 646. Coinynissure of the optic nerves, iii. 673. 076 ; iv. 1446. antero. posterior of fornix, iii. 675. See Fornix» Coimnisswes of cerebellar hemispheres, iii. 685. of the brain, iii. 701. longitudinal commissures, iii. 701. superior longitudinal, iii. 701. longitudinal tracts, iii. 701. fornix, hi. 701 . tsenia 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, hi. 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- belli 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 tlhrd ventricle, anterior, iii. 670. posterior, iii. 676. soft, or grey. iii. 677. Communicans noni, or internal descending cervic.il 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 tlie, 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. Coinplexus muscle, i. 371. 732. Compressor narium minor, iii. 729. Compressor venee dorsalis penis muscle, ii. 446 ; iii. 916. Compressorcs urethrae muscles, iii. 932 ; iv. 1247 ; s. 138. Cofnpressorium, the, iii. 347. See Microscope. Conception, physical action in, iii. 72 1. ch inges 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. CoNCHiFERA (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, 095. nervous system, i. 704 ; iii. 603. organs of digestion, i. 695. of circulation, i. 698. ' of respiration, i. 699. of generation, i. 700 ; ii. 410, 3 I) 3 70)0 GENERAL INDEX. CoNci! iFH R A — continued. organsof motion, i. 700. skin an'l its appendages, i. 705. ! . mantle, i. 705. 2. siphons, i. 707. H. shell, i. 707. cardinal edge, i. 70R. general structure, i. 707. hinge, i. 707. ligament, i. 708. 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. the lunula, i. 71 1 . 5. the corselet, i, 71 1. internal surface, i. 712. formation of mother-of-pearl and of pearls, i. 712, 713. Concretions, or pseudo-calculi, iv. sG. See Products, Adventitious; found in tlie paunch and reticulum of Uuminantia, s. 538. polypous, in the heart, ii. G48. of prostate gland, iv. 1.58. Concussion, depression of the heart’s action consequent on. i. 723. Condillac's dreams, iv. G^7. Condiments, emidoyment of, in diet, ii. 15. Condyles of femur, iii. -14. humerus, external, i. 217. internal, i. 217. extensorius of humerus, ii. IGO. of the tibia, ii. iGh. Condyloid foramen, i. 732. posterior, i. 732. anterior, i. 732. processes, i. 732 j ii, 215. Condylopeda, i. 245. Conferva fontinalis, arrangement of the sexual reproduc- tive organs ofthe, s. 220. Confervoiti Algaj. See Alga* ; Keprohuction, Vegetable. Conflux of Majendie, anterior, iii. G40. inferior, iii. C40. posterior, iii. G38. G40. G88. superior, iii. G40. Congenital deformities. See Teratology. Conger, tongue of the, iv. IMG. Congestion of the liver, iii. 183. a. general congestion, iii. 181. h. hepatic venous congestion, iii. 184. e. portal venous congestion, iii. 1H4. of tlie venous sinuses of tlie spinal cord, iii. 713. convulsions, iii. 713. spinal apoplexy, iii. 713. Conglobate glands, i. 23. Congregatum, instinct of, both in man and in the lower animals, iii, IG. imperfect societies of insects, iii. IG. for society alone, iii. 16. of males in the pairing season, iii. IG. for emigrating togetlu'r, 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. 970. Conical appendages to head of Pteropoda, iv. 175. Conium. use of, in cases of muscular disturbance, iii. 721. II. Conjoined tendons, the, i. 6. Conjunctiva (in human anatomy), ii. 173. 17G; iii. 83. See Lachrymal Organs. structure of, ii. 176. Conjunctivitis, iii. 86. Conochilus. a genus of Uotifera, iv. 402. Conochilus volvox, a species of Rotifera, iv. 401, ct 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. 1 133. relations and action, iii. 952. pharyngis muscle, iv. 1102. pharyngis muscle, inferior, iii. 102, 946. medius, iii. 94G. superior, iii. 946. vaginse muscle, i. 178; s. 712. Consumplion, tubercular, aplionia a symptom in cases of, iii. 119. sympathetic ulceration of the trachea and bronchial tubes in cases of tubercular, iii. 1 19. Contractility, i. 716. 1. irritability, i. 717. 2. vital power or property of irritability, i. 719. 3. conditions accessaiy to the contractile power, i. 721. Contractility — continued, 4. laws regulating tlie vital powers of contr.aotilo powers, i. 723. conclusions, i. 724. Conlractility of muscle, i. 716 ; iii. 5l9. is it a property inlierent in muscular fibre ? doc- trine of the “ vis insita ” of Haller, iii. 519. source of contractility, whence derived, iii. 5-'0. relation of contractility to the state of nuti ilion 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 tlie mus- cular irritability, iii. 521. See Muscular Motion. of cavities of tlie heart, duration of, after death, ii. 607, 608. Contraction, or systole, ofthe auricles and ventricles ofthe heart, ii. 602, 603. See Heart, Physiology of. Conus arteriosus of Woolf, ii- 581, note. Convoluted tube forming the lymphatic gland, iii. 218. See Lymphatic System. Convolutiojis of tlie brain, iii. 693. lunctions of the cerebral convolutions, iii. 722 X. connexions of the functions of the mind witli 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. Conviilsiojis, congestion of the vessels of the brain conse- quent on, iii. 713. 720 F. cause ofthe convulsions of epilepsy, iii. 721 G. of tlie foetus in utero, ii. 321. Cooking, imp ortance of, in digestion, ii. 12. chemical changes induced in food by the process of cooking, s. 390. roasting meat, s. 390. boiling meat, s. 390. salting and smoking meat, s. 391. Cophias, poison fangs of, iv. 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-acroinial ligament, i. 3-50. Coraco-brachialis muscle, i. 217. 219. 359 ; ii. ICO; iv. 756. Coracoid notch (incisura semilunaris, lunula), ii. 156. jirocess, i. 350 : ii. 157 ; iv. 600. fractures of the, iv. 600. in Carnivora, i. 466. 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 tor the abode of man, iv. 33. Corallidic, 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. 393. constituents, s. 393. bread, s. 393. Com-tields, ravages of tlie wire-worm in the, ii. 861. Cornea, ii. 175 — 177. chemical composition, il. 177. development, ii. 178. size and shape, ii. 176; iv. 1440. structure, ii. 175. wounds and diseases of the cornea, ii, 177. conjunctival covering of the, iii. 87. opaca, ii. 175. 177. transparens, ii. 175, 176. conical, symptoms of, iv. 1464. Cornicula laryngis, or tubercles of Santorini, iii. 101, 102. Corns, hard, causes of, ii. 353. solt, causes of, ii. 3.53. on roots of fingers, ii.524. Cornu Ammonis, lii. 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 elans penis, iii. 914. Coronce, \. 728. See hone. GENERAL INDEX, 7G7 suture, i. 736. C'oronaria ventriculi, or proper gastric, arterj% i. 194 ; iii. 9-11 ; s. 325. ventriculi vein, iv. 1414. Coronary arteries, i. 189. 192. 194 ; ii. 584. labial, inferior, i. 486. superior, i. 487. ligament, i. 251 ; iii. 161. of the liver, iii. 940. plexus of nerves, superior, s. 429. sinus, iii 6.'13. 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. 162. 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. 264. mammillaria, or albicantia, iii. 673. 676. 701 . fibrous matter and connections, iii. 701. structure, iii. 701. olivaria, olivge, 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. Araiitii, i. 223 ; ii. 581. callosum, the, iii. 025. 674. longitudinal tracts of, iii. 674. 702. connexions, iii. 702. fibres of corpus callosum, iii. 702. development, iii, 702. anterior reflected portion, Ui. 675. office of the corpus callosum, iii. 723 D. cavernosum clitoridis. erectile tissue of, ii. 44G. cavernosum penis, iii. 912. structure, iii. 912. crura penis, iii. 912. ligamentum suspensorium penis, iii. 912. trabeculae, iii. 912. septum pectiniforme, iii. 913. vaso-cellular 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. conicuin. See Parovarnon. dentatum, or rhomboideum, cerebelli, iii. 683, 684. 692. fimbriatura, iii. 675, 676, geniculatum, externum, iii. 700, internum, iii. 700. fornicis, iii. 676. glandulosum, iv. 146. See Prostate Glaisd. urethra, iv. 1264, 1265. Highmori, iv. 977. luleum, nature of a, s. 564. 569. origin and formation of the, ii. 449. lobular structure of the, ii. 449. 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. sesamoideum, 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. 075. Corpuscles of the blood, i. 404. See Blood. appearance of, in the chyle, iii. 222. ganglionic, structure of, s. 43G. Malpighian, iv. 775 — 779. functions of the, iv, 799. Corpuscles — continued, of Morgagni, ii. 581. or cells of bones, iii. 850. See Osseous Tissue. Pacinian. See Pacinian Bodies. of pus, iv. 111. seminis. See Spermatoxoa. Corpusculum Weberianum. See Vesicula Prostatica Corrugaior supercilii muscle, i. 748 ; ii. 222 ; iii. 80. See Cranium, Muscles of the. Cortical substance of the kidney, iv. 236. polyps. See Corallidce. Coryne, ova of, s. [127.] CoryphodoUi the. See Pachydermata. Cost(S, or ribs. See Ribs. Costal cartilage, iv, 1024. 1031. muscles of Vertebrata, iii. 542. sulcus, iv. 1026, Cosfo-abdominal muscle, i. 5. -coracoid ligament, i. 3G0, -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 ligament, iv. 1033. Coiugno, liquid of, ii. 536. Colunniixs^ nerve of, ii. 287. Cotyloid cavity, or acetabulum, s. 116. fossa, s. 116. 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, et seq. Coursing birds (Cursores), characters of, 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. Com, morbus, iv, 434. Coxalgia, 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. CrabronidcB, a family of the order Hymenoptera, ii. 865. Cratnp, or spasm, iii. 720 K. Cranial aponeurosis, i, 748. sinuses, iv. 1387. Cranio-vertebral nerve, iii. 707. Cranium (in human anatomy), i. 725. analogy between a cranium and vertebra, i. 740. and several vertebrae, i. 740. articulation of the cranial bones— sutures, i. 736. bones of the cranium, i. 726. 1. sphenoid hone, i. 726. articulations, i. 728. body of the bone, i. 72G. cells, sphenoidal, i. 726. development, i. 728. - surfaces, i. 726. 2. frontal bone, i. 728. articulaiions, 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. 73! . 732. connexion, i. 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. 3 D 4 GENEKAL INDEX. ?C8 Cranium, bones of — continued. U. parietal bone, i. 73'). ancles, 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 witliin the, i. 678. motions observable at each arterial pulsation, i. 678. development of the cranial bones, i, 7*11. divi.sions of the cranial bones, i. 725. base, i. 725. anterior, i. 739. mid istatella niucedo, 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 seq. } teeth of, iv. 895. tongue of the, iv. 1146, 1147. vocal organs and voice of the, iv. 1502. Crocodilidee, a family of lleptilia, iv. 265, et seq. Crop, craw, or ingluvies ol birds, uses of, ii. 11 ; s. 301, of insects, s. 298. Crotalus durissus (rattlesnake), anatomy of the, iv. 283, ( t seq, Cioton sebiferum (tallow-tree), i. 58. Croup, or acute laryngitis of children, iii. 115. age at which it occurs, iii. 1 15. condition of the lungs and brain in fatal cases of, iii. 116. false or adventitious membrane of croup, iii. 116. origin of, iii. 1 15. stages of, described, iii. 115. first stage, iii, 1)5, second stage, iii. 115. third or last stage, iii. 116. bronchial, s. 293. acute asthenic, of adults, or diphtherite, iii. 117. cerebral. See Cro?/p, spasmodic, spasmodic croup described, iii. 124. hypotheses as to causes of, iii. 124. Crojtpy or diphtheritic inflammation of the alimentary canal, s. 4] 1. Crown of the head, i. 747. Crucial ligaments, i. 251. of knee, anterior, iii. 46. posterior, iii. 40. Cruor of blood, analysis of, i. 415, Crura cerebelli, ii. 270. 272 ; iii. 674. 677. 685. 692. peduncles of crus cerebelli, iii. 693. inferior, iii. 693, middle, iii. 693. 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. 11 ; ii. 3. jienis, Iii. 912 ; s. 138. artery of the, iii. 934. Crnrreus muscle, nerve for the, iv. 763. GENERAL INDEX. 769 Crural arch, i. 5, note^ 13 ; ii. 756, 757 • canal, ii. 757. fascia, or fascia lata, s. 138. nerve (femoral), iv. 762. branches, iv. 763, 7G4. anterior, ii. 779 j iv. 761. ring, ii. 757. passage of the testicle through the, iv. 988. vein, anterior, ii. 838. Crural or femoral hernia, ii. 756. See Herni.a. symptoms and progress of the disease, ii. 759. Crusla petrosa of teeth, iv. 864, 865. Crustacea (a class of Articulated Animals),!. 111. 246. 750. arrangement of the class, table of the, i. 751 . blood and circulation, i. 652. 775. branchO'Cardiac (efiferent) 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. 762. nervous system, i. 762 ; iii. 608. senses, organs of the, i. 707. 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 j iv. 309. moult, or process of renovation of the tegumen- tary skeleton, 1. 759. reproduction of extremities, i. 760. temperature of, ii. 650. periodical exuviation of the shell of Crustacea, iv 571. list of Crustacea possessing the properly of luminous- ness, iii. 197. See Luminodsness, Animal. effects of atmospheric electricity on, iii. 36. Cryptogamia, mode of reproduction of the higher, s. 232. vegetative system among the lower Hepatic®, 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 Jungermanni® frondos®, 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. 236. changes preparatory to the development of the spores, s. 236. Mosses, s. 237. first period — gemination of the spore, s. 238. development of the antheridia and ardiegonia, 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. 24 !. sporangia and spores, s. 241. Equisetace®, s. 241. first period — germination of the spores, s. 241. antheridium, s. 241. archegonium, s. 212. spores and sporangia, s. 242. Lycopodiace®, s. 243. commencement of the development of the pro- thallium, s. 243. archegonia, s. 243. embryo, s. 243. sporangia and spores, s. 243. Rhizocarpe®, s. 245. macrospore of Pilularia, s. 245. prothallium, s. 245. embryo, s. 245. sporangia and spores, s. 246. Crypfogamia — continued. 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, 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 and development of germ-cells in special organs destined for their reception, s. 253. Cryptomonadinidcs, a family of Polygastiic Animals, iv. 3. characters of the family, iv. 3. Cryptops^ a genus of Myriapoda, iii. 547, et seq. Crystallme lens, or crystalline humour, of the eye, ii. 194. 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. CtiIus. 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-scaphoid articulation, ii. 343. Cupola of cochlea, ii. 531. Curculiomdcc^ ii. 864. Curd and whey, mode of converting milk into, s. 53s. Cursores, or coursing birds, characters of, i. 26H. Curvature of 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 anticus, 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. peron®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 sapb®nus nerve, iv. 764. Cuticle, the, iii. 489. Cutis, 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. sepiuni, or cuttle-bone, i. 531. 546. ink-bag of, iv. 453. ova of, s. [10-5], [106.] Cuttle-fishes, or Sepiad®, i. 521. CyaJiea aurita, ova of, s. [129.] Cyanogen, discovery of, iii. 15i. combinations of, ■with metals, iii. 151. effect of, on the action of the heart, i. 797. Cyanosis, i. 190. a sub-tribe of Insects of the order Coleoptera, ii. 862. characters of the sub-tribe, ii. 862. Cyclidmid(Z (disk animalcules), a family of Polygastric Animals, iv. 4. characters of the'family, iv. 4. Cyclobranchiata, ii. 379. See Gasteropoda. Cyclodus nigroluteus, teeth of, iv. 891. Cycloglena, a genus of Rotifera, iv, 404. Cyclopia, iv. 944. 958. 9' 7. Cyclopian, or Cyclocephalian, monsters, congenital defect of the nose in, iii. 737. optic nerves in human cydopian monsters, iii. 777. abnormal conditions of the brain in, iii. 719. 770 GENERAL INDEX. Cyctostomata, ;m order of Fislies, iii. 9r«7, ct svq. characters ol the order, iii. 957. nervous system ol the, iii. GH. Cydippe pileus, the, iii. .“iSS. organs of locomotion in, i. 39, 40. CydoJiium Mullcri, a genus of polyp, iv. 19. Cylindrical eye, iv. MG7, method of detecting the defect, iv. 14G8, 1409. Professor Stokes’s astigmatic lens, iv. 14G8. treatment, iv. 1409. fibro-cartilages, i. *249. Cylindrosoma, a genus of Myriapoda, iii. .54G, ct scq. maligna, iii. 118. ItiO, 121. anasarca consequent upon, iii. 118. p.arotidea, or mumps, iv. 430. Cynipklce, or gall-flies, ii. 8G6. habits ofthe, ii. 8GG. Cynoccphalus (baboon), a genus of Quadrumana, iv. 197, ct scq. See Quadiujmana. characters of the genus, iv. 197. Cynthia, a genus of Tunicata, iv. 1 187, ct seq, characters of the genus, iv. 1 IH7. nervous system of the, iii. C03. Cynthia Dione, i. 112. Cyphonautcs, a genus of Rotifera, iv. 402. Cypvinidce, a family of Fishes, iii. 957. dental api)aratus of, iii. 979. 0/67, i. 7H7. definition, i. 787. develojimem, i. 790. first class of cysts, i. 788. second class of cysts, i. 789. See also Adhesion. 0/6/ worms. See Entozoa ; Sterclminlha. Cystic artery, i. 195. duct, iii. 1G4. 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 Kn- TOZOA ; Sterchnintha. Cysticercus cellulosai (Mydatis Finna of Rudolphi), an entozoon of the human muscles, ii. 1 18, 1 10. 127. 131. case of one found in the anterior chamber of the eye, ii. 1 19. and in the brain, in. 720 E. fasciolaris in the river of rats, ii. 115. no nervous system discovered in the, iii. C07. mode of reproduction of, s. 2G. Cyslin, or cystic oxide calculus, iv. 70. deposit of, in urine in disease, iv. 1283. Cystingia, a genus of Tunicata, iv. 1188, ct scq. characters of the genus, iv. 1188. Cyslis fellea. See Gi7//-bladder, Cystitis, acute, i. 397- characters of the urine in, iv. 1292. Cijtahlastcmal formations, iv. 100. See Products, Adven- titious. Cystocele, i. 395. Cystoma. See Pseudo-tissues, serous. CV/6/6, 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. multii)le, s. .570. muliilocular, compound, or proliferous cysts, s. 580. contents of ovarian cysts, s. 582. fluid contents of cysts, s. 5H2. 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. fadus 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 tlie cortical portion of the kidney, iv. 200. in the substance of the testicle, iv, 1010, in thyroid gland, iv. 1116. of the tongue, iv. 1 157. of the urinary bladder, i. 303. D. Dacryoliihs, or lachrymal calculi, iv. 82. example of the formation of, iv. 82. Dactylopferns, or flying fish, mode of flight of the, iii. 429. Dahoinans, physical and mental characters of the, iv. 1353. J)(iUonis7n, \v. 1452. Achromatopsy ; Vi.sion. Dancing, injuries of the tendons of the leg caused by, iii. 132. Daphnidec, ovum of, s. [116.] [127.] Darien, Isthmus of, Albinoes of the, i. 84. 7)//r/.7/«g-beetle (Blaps mortisaga), ii. 863. Da)tos, or tunica, scroti, iv. 438. 9S6. Dasyprocta, or agouti, anatomy of the, iv. 373, et scq. 79a6^/ms longicaudus, or armadillo, s. 163. Dasyurus, a genus of Marsupialia, iii. 259, et scq. 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, tlie 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. 1.53. irritability, extinction of, i. 793. nutrition, arrest of the fluid of, i. 792. depravation of the fluid of, i. 792. 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 org-ins, 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, i. 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. 808. Iividilies of the surface, i. 808. rosy hue of the cheeks, i. 807. state of the eyes, i. 807. changes in the tissues, 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. 80S. mean ago at, iv. 1470. Death-rattle, i. 801. Death-sti'uggle, or agony, as a sign of approaching death, i. 800. Dcath-vatche% (Ptinidoe), ii. 862. their ravages in houses, ii. 862. Dccapoda, nervous system of the, iii. 609. organs and mode of locomotion of the, on solids, iii. 436. 444. Decay of animal structures, iv. 4-56. periodical decomposition, iv. 4.56. carbonic acid the first product of animal deca}', 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. 4.56. hydrocarbon of biliary secretion, iv. 458. nature of faecal matter, iv. 458. Decay of man, i. 77. Decidua, ii. 455. 457. Decidua reflexa, or decidua cbordii 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. 6-56. Deer, anatomical characters of, s. 508, et scq. connexion of the generative tunction 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 of the, iii. 454. speed of the, iii. 454. pelvis of, s. 1.57. GENERAL INDEX. 771 Beer — continued. skeleton of the, s. 507. skull of, s. 511. Weberian organ of the, iv. 1421. 142'^, Deer. red(Cervus elephas), calculus of the— “ deer’s tears,” iv. 82. Defeecntion, 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. 180. part taken by the abdominal muscles in aiding, i. 16, 17. sketch of the phenomena of, s. 371. the faeces, s. 372. See Ftsces. condition of, during the sleep of hibernating animals, li. 768. 772. Bef(Ecation of hair, iv. 142. Bejiuration of a virgin during ordinary sleep, iv. 6S2. Beformitij., congenital. See Teratology. Deglutition^ process of, ii. 8; iii. 760 ; s. 311. 398. analysis of the act of, iii. 721 1. exciting cause in the movements of, iii. 722 K. function of the pharynx, mouth, and palate, in deglu- tition, iii. 953. function of the cesophagus in, iii. 759. involuntary nervous action in, iii. 589. uses of the salivary glands in, iv. 429. functions of the tongue in, iv. 1152. first stage : oral, iv. 1 152. second stage : pharyngeal, iv. 1152. third stage; oesophageal, iv. 1153. difficult cases of deglutition, iii. 119, 120. Bcilephila Elpenor,.or Elephant sphinx, ii. 8G7. BeirodoHy teeth of the, iv. 886. * Bdh'iuin 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. Belnhinidce, 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, ICO. Dementia., iv. 686. preceding death, i. 799. Dendrodoa., a genus of Tuuicata, iv. 1 187, et seq. characters of the genus, iv. 1 187. Dendrodus, teeth of, iv. 869. Deiital, 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. 214. nerve, inferior, ii. 292. 294. course, ii. 294. posterior superior, ii. 289. anterior superior, ii. 289. vein, inferior, iv. 1405. system (in comparative anatomy). See TfeETH. Dentate body, iii. 692. fascia, ii:. 675. Dentated ligament (serrated membrane of Gordon), iii. 645. office of the, iii. 645. Dentine y iv. 864, 86*>. Dentes 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. 234. adventitious, on the heart, ii. 644. atheromatous, in veins, iv. 1402. Depressor al® nasi (musculus myrtiformis), ii. 223 ; iii. 728. relations and action, iii. 728. anguli oris muscle, ii. 225. relations and action, ii. 225. labii inferioris muscle, ii. 225. relations and action, ii. 225. septi narium muscle, iii. 729. relation and actions, iii. 729. urethrae muscle, iv, 1264. Derbesia, mode of reproduction of, s. 214. Dermal system of Amphibia, i. 102. Dermaptera, an order of Insecta, ii. 863. 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. Desnendens noni nerve, iii. 721 ; iv. 754. Desmidice, mode of reproduction of, s. 218. Desiccalioyi of organic substances, iii. 793. method of per'orming, iii. 797, 794. apparatus for desiccation of organic subst.ances, iii. 813. Detrusor urinae muscle, i. 381 ; iv. 1263. Devil of Van Diemen’s Land (Dasyurus ursinus), iii. 259. mellitus, iv. 97. specific gravity of the blood in, i. 416. state of the blood in, i. 427. effects of diabetes on the circulation, i. 798. 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, eflects 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, il. 4. muscles, ii. 2; iii. 544. costal, upper, true, or greater, il. 2. centrum tendineum.cordifoi m tendon, ii. 2. ligamentum arcuaium 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 diaphragmatica, iv. 2. relations to the pleura, peritoneum, Sic., ii. 4. veins, ii. 4. malformations and diseases, ii. 6. absence, ii. 6. cartilaginous and osseous deposits, ii. 6. displacement from ascites, See. ii. 6. gangrene, collection of pus, tumours, &c., ii. 6. inflammation, ii. 6. openings, ii. 6. rupture, — risus Sardonicus, ii. G. ulcers, ii. G. wounds, ii. G. uses of the diaphragm, ii. 4. l>art performed by the, in respiration, iv. 324. 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. Diaphragmiiis, ii. 6. Diarrhoea, syncope from, i. 797. colliquative, occurrence of, in animals reduced by star- vation, iii. 752. DiarUirodial ca.TX.\\nge, 1. 248. 255. See Articula i ion. Diarthrosis, class of articulations, i. 255. arthrodia, i. 256. onarthrosis, i. 2-56. ginglymus. i. 256. rotatoria, i. 256. synarthrodica, form of articulation, i. 266. 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. 1190, et seq. characters of the genus, iv. 1 190. Dihranchiata, i. 519. characters of the order, i. 519.* Dichitonida, a sub-class of Tuuicata, 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 Pachydermata. Dictyotacece, mode of reproduction of the, s. 216. Dicynodon lacerticeps, skull of, iv. 889. Didelphys, a genus of Marsupialia (opossums), iii. 261, et seq . characters of the genus, iii, 261. species of, iii. 261. Didelphys cancrivora, iii. 261. opossum, organs of voice of, iv. 1491. cyuocephalus, or hy$na of Van Diemen’s Land. iii. 258, et seq. Virginlana, 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. 1190. Didus ineptus (dodo), account of the, i. 269. 772 GENERAL INDEX. Diet and regimen, eflfectof, on tlie evolution ofanimal heat, ii. 082. Dietaries, observations on, s. 396. quantity of lood required per diem, s. 397. Digastric muscle, iii. 105. 563. action and relations, iii. .563, 5G-1. nerve, iii. 949 ; iv. 5-17. space, iii. 564. .570. 581. anterior division, iii. 581. posterior division, iii. 581. sulcus, i. 734. Digestion, ii. 6. definition, ii. G. I. description of the organs of digestion, ii. 7. moutli, with its appendages, ii. 8. lips, ii. 8. salivary glands, ii. 8. teeth, ii. 8. cesophagus and deglutition, ii. ft. stomach and intestinal canal, ii, 9, 10. movements of the stomach at the commence- ment of, s. 312. a. when a large quantity of food is hastily swallowed without mastication, s. 312. 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 tlie stomach in the later stages of digestion, s. 314 changes in the stomach during digestion, s. 328. gastric juice, s. 328. physical propenies, s, 329. specific gravity, s. 329. quantity, s. 3.30, chemical composition, s. 330. action, s. 333. process of secretion, s. 337. changes in tlie villi of tlie intestine during di- gestion, s. 355. llieories of the process of stomach digestion, s. 336, 337. peculiarities of the digestive organs in different classes of animals, ii. II, 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, ii. 17. 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 peculiar 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. 39H. gastric digestion, s. 398. intestinal digestion, s. 398. the bile, s, 399. effects 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. 768. See also Nutrition. animal and vegetable digestion compared, i. 132. Digestive Canal (in comparative anatomy), ii. 27. See the various classes of Animals, under their liead- ings. Digi.at arteries, iv. 226. 1407. cavity, or fossa trochanterica, ii. 166; iii. 674. nerves, iii. 904. first, iv. 757. second, iv. 757. third, iv. 757. fourth, iv. 757. fiftli, iv. 757. terminal, iv. 757. Digitalis^ action of, on the vital power of the heart, i. 723 797 Digiti pedis, toe bones, ii. 342. Diglcna, a genus of Uotifera, iv. 404. Diglena lacustris, digestive organs of the, s. 295. 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 ihe, at a distance, iv. 1446. instance of Napoleon Bonaparte, iv. 141'). Dimyaria^ i. 695. See CoNChieera. Dingo, or wild dog of Australasia, iii. 257, note ; iv. 1305, 1307. Dinobryna, a family of Polygastric Animals, iv. 4. Dinocharis, a genus of llotilera, iv. 406. paupera, iv. 412. Dinornis, pelvis of the, s. 168. Dinotherium, anatomy of the. See Pacuydermata. teeth of the, iv. 9.31. Diodons, mode of progression of the, iii. 437. teeth of, iii. 980. Diceewus reproduction, or generation with d'slinct inili viduals of different sexes, ii. 435. See Generation. Dioptric phenomena, iv. 1440. Diphtherite of M. Bretonneau, iii. 117. symptoms and appearances of, iii. 1 17. sloughing, iii. 118. differences between it and croup, iii. 118. diphtheritic deposit, iv. 118. white thrush, iv. 1 18. white cheesy substance, which forms on blistered surfaces, iv. 118. Di- hyda (Acalephae), i. 36. Diphyrs campanulifera, i. 38. Diplj'e, condition of, in erysipelas, i. 745. Dii’Logenesis, i. 509. Diploic plexuses of vein«, iv. 1388. DiplosUmium volvens, an Entozoon infesting the eyes of animals, ii. 121, 122. 132. organs of digestion of the, s, 296. Diploxoort 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 her.siiies, or jerboa, anatomy of the, iv. 369, et seq. Direction, sense of, of some animals, iv. 702. Disarticulations of hand, ii. 529. Discoboli, a funily of Fishes, iii. 957. Drscomycetes, 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 a magnify- ing power, iii. 346. instruments for microscopic dissection, iii. 346. Swammerdam’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 Uotifera, iv. 404. Disioma (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. deiuiculatum, ii. 127. ferox, ii. 127. Iiepaticum (or liver-fluxe), description of the, ii. 12- 132. in veins, iv. 1402. nervous system of the, iii. 607. Ilians, development of the young of, ii. 1 43. 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 ot Tunicata, iv. 1 190, et seq. characters of the genus, iv. 1 190. Diuinn, day-fliers or butterflies, a section of Insects of the order Lepidoptera, ii. 866. characters of the section, ii. 866. O/yersf/fes of mankind, iv. 1315. See Varieties of Man- kind. Diverticula of intestinal canal, s. 401. Diving~hc\\, distressing tension of the tympanum when in the, ii. -575. relief obtained by the act of swallowing, ii, 575. 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. 713 Dog — continued. dentition of the, iv. 907. 909. 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. 1.307. dingo, or wild dog of Australasia, iii. 257. note ; iv. 1.305. 1307. Newfoundland dog, feet and organs of locomotion in water, iii. 439. Dog-fish (Spinax acanthias), sexual organs of the female, iii. 1009. Dolphm^ cardiac pericardium of the, i. 57. Do7nestication of animals, tendency to variation in, iv. 1304. Dondos. See Albino. Dormant vitality, iii. 141. 154. See Life, Vitality, Dor- M.ANT Dormouse (Myoxus), anatomy of the, iv. 376. et scq. digestive organs of the, s. 303. hibernation of the See Hibernation. Dorsal arteries of clitoris, s. 709. 713. artery of penis, iii. 917 ; iv. 1254. of tongue, iv. 1141. 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. 700. intercostal branches, iv. 700. special characters of, iv. 700, internal, iv. 758. of penis, iii. 918 : iv, 766. veins of clitoris, s. 709. of penis, iii. 917. 933 : iv. 1254. vertebrae of Carnivora, i. 475. See Carnivora. Dorsalis pollicis artery of hand, iv. 223. Dorsi-spinal^ems., iv. 1410. Durso-abdominal vessels, i. 170. Dorsum pedis, or instep, ii. 339. 351. 3'7. See Foot. muscles of the. ii. 358. Doublets of Herschel and Wollaston, iii. 335. 338. See Microscope. Draco volans, anatomy of, iv. 272, et seq. Dracunculus^ or Guinea worm, ii. 122. See Entozoa ; Filaria Medinensis. Dragow-flies (Libellulina), ii. 864. wings and mode of flight of. iii. 423. mode of progression of the larvie of some species, iii. 434. Drea7ning, iv. 678. 687. definition, iv. 687. chief feature of the state of sleep, iv. 687. reasoning processes and the imagination, iv. 687. incoherence and incongruousness of the thoughts and images which pass through our minds in dreams, iv. 688. absence of contr- l over the muscular system, iv. 088. incubus, or n’ght-mare, iv. 688. direction of the current of thought often given by impressions on the organs of sense, iv, G8S. rapidity with which trains of thought pass through the mind, iv. 689. analogous action of narcotics on the nervous system, iv. 690. the hachisch or dawamesc of the East, iv. 690. intense dreaming, — somnambulism, iii. 723 B. Dromedary^ structure of the hump and cushion-like sole- pad of the, s. 531 . Dropsical effusions in the fcetu.s in utero, ii. 332. Dropsy, anasarcous, consumption of fat in, i. 63. characters of the fluid of dropsy, iv. 144. of the spinal medulla, iv. 957. Drowning^ death by, appearance of the body after, i. 269. Drowsiness, cause of, i. 416. Drum of the ear, or tympanum, ii. 543. See Hearing, Organ of — tympanum. Drunke7iness, a cause of wasting of the brain, iii. 720. delirium tremens, iii. 720. Duct, cystic, iii. 164. efferent, of epididymis, iv. 979. or excretory, of the lachrymal glands, iii. 89. discovery of the, iii. 89. uses of the, iii. 89. of the testicle (vas deferens), iv. 980. hepatic, Hepatic 6.nct. , Liver. ofMiiller, s 594.597. 613. nasal, iii. 90. 92. 725. See Kasai duct, pampiniform, iv. 982. of pancreas, s 84.89. calculi of the, iv. 86. of parotid gland, or duct of Steno, iv. 423. of Rivinus, iv. 425. Steno’s, iv. 1404. thoracic, iii. 579 ; iv. 816. Wharton’s, iv. 424. Ducts, hepatic, in Carnivora, i. 479. See Carnivora. Ductus adiposi, i. 59. arteriosus, i. 190. Ductus — conlmutd. communis choledochus, i. 386; iii. 164. venosus, fissure for the, iii. IGl. Dvgong, digestive organs of the, s. 304. teeth of, iv. 866. Dumb7iess, reason why persons born deaf are also dumb, iv, 1173- £)2<7?g^-beetle, ii. 860. Duodc7ial glands, s. 361, 362. loliules of, s. 361. Duodcnu7n, the, s. 308, 300. 340. curvatures of, s. 308. first, or superior transverse, or liepatic portion, s. 341. second, or descending, or vertical portion, s. 341. third, or inferior transverse portion, s. 341 . peritoneum of the. iii. 943. development of the, s. 402. uses of, in digestion, ii. 10. See also Stomach and Intestine. Dura mater, iii. 627. cranial, iii. 628. processes of the cranial dura mater, iii. 62?. falx cerebri, iii. 629. falx cerebelli, iii. 629. tentorium cerebelli*, iii. 629. spinal, iii. 628. affections of the dura mater, iii. 713. vessels of the cranial dura mater, iii. 630. sinuses, iii. 631. cavernous, iii. 633. circular, iii. 633. lateral, iii. 632. longitudinal, inferior, iii. 631. superior, iii. 631. occipital, iii. 632. petrosal, superior and inferior, iii. G32. strait, iii. 631. torcular Herophili, iii. 631. transverse, iii. 632. vessels of the spinal dura mater, iii. 629. abnormal anatomy of the dura mater, iii. 715. general or partial deficiency, iii. 715. acute diseases, 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. Duration of human life. See Vital Statistics. in the organic and inorganic world, i. 121. Dycrasia, iv. 801. Dynaniic office of the nerves, iii. 586. Dyyiastcs Hercules, ii. 861. Dynastidee, ii. 859, 8G0. Dysentery, chronic, condition of the adipose tissue in, i. 63. morbid appearances in, s. 415. progress of the disease, s. 415. ulceration of the tongue, iv. 1154. small circular ulcers, iv. 11.54, severe and deep-seated ulcers, iv. 1155. aphthous ulceration, iv, 1155. Dysphagia, occasioned by abscess in the neck connected with diseased vertebrae, i, 452. lusoria, iv. 818. Dyspnoea, iv. 1083. cause of, i. 416. aftpr section of the inferior laryngeal nerves, iii. 894. action of the auxiliary muscles of respiration in cases of, iv. 335. glottic, operation for, iii. 573. hysteric, of young females, iii. 124. Dyticidee, a sub-tribe of Coleoptera, ii. 860. Dyticus marginalis, nervous system of the larva of, iii. 611. Dzigguctaif or Equus hemionus, iv. 714. E. Eagle, brain of, iii. 765. pelvis of the, s. 169. Ear, the, ii. 529. See Hearing, Organ of. in infancy, i. 73. in old age. i. 80. muscles of the (in comparative anatomy), iii. 544. of Cetacea, i. 586. See Cetacea. of Fishes, iii. 1002. of Marsupialia, iii. 296. Ear-bulb, ii. 529. 557. See Hearing, Organ of ; La- byi'inth, osseous. Ear-cockle, or Purples, of wheat, cause of the, ii. 113. Ear-drum. See Hearing, Organ of; Tympanu7)i. Ear-wax. See Cerumen ; Hearing, Organ of. Earthu’or/n, organs of generation in the, i. 172. See An- nelida. vitality of separated portions of the, i. 172. luminousness of the, iii. 198. nervous system of the, iii. 607. GKN EKiVL INDEX. 774^ Earthwor^n — cotiliuucd. organs ol' circulation in, i. G50. organs and mode of progression of tlie, iii. 4 U. Earthy concretions in the pituitary body, iii. 70^i. degeneration of the arteries in old age, i. '.^31. of the laryngeal cartilages, iii. 121. particles of bones, absorption of, i. 44-1. salts of bone, i. 437- in various animals, i. 437, 438. Earung,s (rorliculida:), ii.863. mode of flight of tiie, iii. 4*21. EcchymosiSy cause of, i. 422. 515. subconjunctival, iii. 85. Echidna, a genus of IMonotrcmata, iii. 367. species of, iii. 367. characters of the genus, iii. 3C7. See Monotkemata. generative system of, ii. 409- organs and mode of locomotion of the, iii. 440. Echidna hystrix, described, iii. 367, ct scq. See Monotue- MATA. pelvis of the, s. 161. structure of the spines of the, S..498. structure of the ovum in, s. [91.] setosa, df'seribed, iii. 367, ct scq. See Monotkemata. Echimys. or porcupine rat of Azara, anatomy of the, iv. 372, ct scq. Echmococczis, a genus of Rntozoa. ii. 117. See Entozoa. digestive organs of the, s. 295. mode of reproduction of, s. 25. hominis, ii. 118. an entozoon found in the brain, iii. 720 E, mode of reproduciion of, s. 26. Echinodeumata (a class of Invertebrate Animals), i. 109; ii. 30. systematic arrangement of the class, ii. 30. digestive organs, ii. 36. in Asterias, ii. 36. in Echini, ii. 38. in Holothuria?, ii. 39. generation, organs of, ii. 44. 409 ; s. 297. in Asterias, ii. 45. in Echini, ii. 45, in llolothuria}, ii. 45. ova of, s. [125.] mode of reproduction of, s. 14. spermatozoa in Echinodermata, iv. 498, motion, organs of, ii. 34 ; iii. 440. in Asterias, ii. 34. m Echini, ii, 35. in llolothuria;, ii. 36. muscular system of the, iii. 537. nervous system, ii. 44 ; iii. 602. in Asterias, ii. 44. in Ecliini, Ii. 44. in Holotliuriae, ii. 44. regeneration of lost parts in Asterias, ii. 45. respiratory organs, ii. 40. in Asterias, ii. 40. in Echini, ii. 41. in Holothuria?, ii. 41, tegumentary system, ii, 31 ; iv. 669 ; s. 485. in AstcriavS, ii, 31. in Ecliini, ii. 32. in Holothurite, ii. 33. vascular system, i. 6-53; ii. 41. in Asterias, ii. 41. in Echini, ii. 43. in Holothuriee, ii. 43. list of Echinodermata possessing the property of lumi- nousness, iii. 198. Echinorhynchus gigas, a species of Entozoa hominis, ii. 127. digestive organs of, iii. 133. muscular and tegumentary system of, ii. 127, 128, 129. generative organs of, ii. 139. EchinuSy ii, 31 . alimentary canal of the, s. 297. cilia in, i. 615. 617. See Cilia. ova of, s. [125.] nervous filaments not found in the, iii. 602. muscles of the, iii. 537. lamina of shell of, iv. 567, 568. See Echinodermata. Echinus esculentus, i. 109. description of, i. 617. ciliary motion in, i. 617. uses, i. 617. See Cilia. EchoeSy phenomena of, ii. 566. Ectocarpus siliquosus, mode of reproduction of the, s. 214. Ectopia cordis, or malposition of the heart, iv 43. 949. congenital, ii. 630. as a consequence of disease, ii . 635. of the thoracic and abdominal viscera, iv. 949. Edentata (a group of Mammiferous Animals), ii. 46. osseous system, li. 48. anterior extremity, ii. 50. cranium, ii. 48. pelvis, ii. 50. posterior extremity, ii. 50. vertebral column, ii. 49. Edentata proper, ii. 51. circulation, organs of, ii. 54. Edentata — conlinu d. digestive organs, ii. .53; s. 30*2. tegumentary system, ii. 54. thymus gland of, iv. 1097. salivary glands of Uuminantia, iv. 433. Eel (Anguilla acutirostris), vasa vasorum of, iv. 13. 8*2. caudal venous heart of, iv. 1383. brain of, iii. 764. respiration of, iii. 985. EJJcrcnl ducts of epididymis, iv. 979. functions of nerves, iii. 7*20 I. nervous fibres, iii. 646. Effusions into sub-arachnoid and arachnoid cavities, iii 716. of serum, iii. 716. of blood, iii. 717. into spinal cord, iii, 715. of pus, iii, 717. Egagropilesy or hair-balls, in the intestines of the lower animals, iv. 84, Egesla and ingesta, s. 382. See Food. See Ovum. white of. See Albumen. nutritive properties of, ii, 13. See Food. of viviparous animals, nature of the, ii. 434. Sec Chneka'i ion ; Ovum. of insects, ii. 869. Egg-shell, formation of the membrane of, iii. 748. Egypt, ophthalmia of, iii. 86. Egyptians, ancient and modern, physical characters of llie, iv. 1357. 7iA/t*r-duck, velocity of the, in flight, iii. 429. Eighth pair of nerves, iii. 684. See Glosso-piiakvngeal ; PakVagum; Spinal Accessory. scminismuscle, iii.929. See Acccleratores uriniu. Ejaculatory duct, calculi in the, iv. 86. Elaine, i. 59. Elasmotherium, the. See Pachydermata. Elastic fibrous organs, yellow. See Fibrous Tissue. ligament, {. 251. tissue, iv. 512. formation of adventitious, iv. Ml. Elasticiiy, ii. 5.5. 1 general remarks, laws, 8rc., of elasticiiy, ii. .56, elasticity and coniractility compared, ii. 56, .57. See Contractility. II, tissues of the body, in the order of their elasticitv. ii. 58. 1. yellow fibrous tissue, ii. 68. 2. cartilage, ii. 68. 3. fibro-cartilage, ii. 58. 4. skin, ii, 69. 5. cellular tissue, ii. .59. 6. muscle, ii. 59. 7. bone, ii. 59. 8. mucous membrane, ii. 59. 9. serous membrane, ii. 60. 10. nervous matter, ii. 60. 11. fibrous membrane, ii. 60. III. instances in which elasticity plays an important part in the mechanism of organised beings, ii. 60. 1. in the protection of the body and its parts, ii. CO. 2. as a substitute for muscular contraction, ii. 61. 3. as preserving the patulous condition of certain outlets, ii. Cl. 4. as subservient to locomotion or movement ge- nerally, ii. 61. 5. as a means of dividing or transferring muscular force, ii. 62. 6. as a means of converting occasional or inter mitting into continued forces, ii. 62. Elasticity of arteries, i. 224. Elatcr noctiJucus, or click-beetle, or West-Iiidian fire- beetle, ii. 861. Elatcridce, a family of Insects, ii. 861. Elbow, Articulation of the, ii. 65. bones, ii. 65. ligaments, ii. 66. motions, ii. 67. extension, ii. 67. flexion and semiflexion, ii. 67. lateral motion, ii, 67. Elhow-juinty abnormal conditions of the, ii. 67. I. Accidents, ii. 68. simple fractures, ii. 68. of the humerus and its condyles, ii. 68. of the ulna, ii. 69. of the olecranon, ii. 69. luxations, ii. 69. of both bones of the fore-arm backwards, ii. 69. of tlie bones of the forc-arm laterally, ii. 71- backwards and outwards, ii.7‘2. backwards and inwards, ii. 72. of the ulna alone directly backwards, ii. 72. of the upper extremity of the radius from tlic humerus and ulna, ii. 72. of the radius at the elbow-joint forwards, ii. 73. of the radius alone laterally, ii. 73. of the radius alone backwards, ii. 74- GENERAL INDEX. 776 Elbow-joint : accidents — continued, sub-luxation of the upper extremity of the radius, with elongation of the coronary liga- ment, ii. 74. congenital or original luxation of the upper head of the radius backward, ii. 75. 2. Diseases, ii. 77. of the synovial membrane, synovitis, ii. 77. of the cartilages — inflammation, softening, ab- sorption, ii. 77. of the bones — caries, clastic white swelling, ii. 78. rheumatism, ii. 79. foreign bodies in the cavity of the joint, ii. 80. Elbow, Region of the, ii. 02. anterior, lateral, and posterior surfaces, ii. 63. aponeurosis, ii. 64, brachial artery, ii. 6l. See Br.\chial Artery. development, ii, 64. lymphatic vessels, ii. 64. nerves, subcutaneous, ii. 64. skin and subcutaneous tissue, ii. 63. varieties, ii. 65. veins, ii. 63. selection of a vein for phlebotomy, ii. 65. Electric eel (Gymnotus), intestinal tube of, iii. 982. light, rapidity of, iv. 1444. Electricity, Animal, ii. 81. electrical fishes, ii. 81. other electrical animals, ii. 82. 1. circumstances under which discharges from electri- cal fishes take place, ii. 82. exhaustion consequent on a continued succession of discharges, ii. 83. 2. motions of the fish in the act of discharging, ii. 83. 3. physiological effects of animal electricity, ii. 83. 4. magnetical effects, ii. 85. .5. chemical effects, ii. 86. 6. results of experiments on the transmission of the discharge through various conducting bodies, ii. 86. 7. production of a spark and evolution of heat, ii. 87. 8. results of experiments in which the nerves, electrical organs, and other parts, were mutilated, ii. 87. 9. anatomy of the electrical organs, ii. 87. in the Gymnotus, ii. 91. in the bilurus or Malapterurus electricus, ii, 93, in the J'orpedo, ii. 88. analogies of animal electricity, ii. 93. manifestations of animal electricity in animal sub- stances and in living animals, ii. 95. uses ot animal electricity, ii. 97. animal and vegetable electricity compared, i. 137. evolution of electricity during the ordinary processes of growth of plants and animals, iii. 154. Elects icily ^ atmospheric, effects of, on some fishes and Crustacea, iii. 36. electric influence the best test cf irritability, iii. 29. 35. is the vis nervosa electricity ? iii. 720 Q. discovery of Galvanism, iii. 29. elpciricity considered as a vital stimulus, iii. 147. Elendnts Templetonii, ii. 866. Elephant, iii, 858. anatomy of the, iii. 859. See Pachyderma ta, brain of the, iii. 696. absolute weight of the brain of the, iii. 664. section of cranium and tusk of the, iv. 9:^3. dentition of tlie genus Elephas, iv. 023. tusks of the, deciduous and permanent, iv. 923, pelvis of the, s. 155. stomach of the, s. 303. teeth of the, iv. 871 . urine of the, iv. 1280. organs of voice of the, iv ] 494. ^Vebel•ian organ in the, iv. 1419. Elephant sphinx moth (Deilephila Elpenor), ii. 867. ElephnnHasis of the Greeks, iv. 993. the disease described, iv. 1013. Elevator auris muscle, ii. 551. £//w-trees, injuries done to, by the Scolytus destructor, ii. 862. ' EXpeivOti irk»TUix.i and of Aristotle, ii. Ill, See Entozoa. Blmbithoida, i. 245. Emasculation. See Castration. Embryo-ceW, s. 4. See Ovum. -genesis, s, 4. Embryology. See Ovum. Eminence, ilio-pectineal, s. 115. thenar, ii. 358. articularis, i. 734. carpi radialis superior, ii. 505. interior, ii. 506. ulnaris superior, ii. 505. inferior, ii. 506. capitata, ii. 65. frontalis, i. 729. pyramidalis, ii. 530. natifoimes, iii. 677. testiformes, iii. 677. papillaris s, protuberantia pyramidalis, ii. 544. Emotion, considered as a mental nervous action, iii. 589. influence of, on the body. iii. 711. Emotional excitement, part of the brain most directly in. fluenced by, iii. 722 P. Emphysema, i. 51G ; 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 j iv. 235, vein, iv. 236. 238. Enciliosaurs, teeth of, iv. 895. Enantiotreta, a section of Polygastric Animals, iv. 5. Enarihrosis, or ball and socket joint, i,251. 256. Encauslum, or enamel of teeth, iv. 865. Encephalic nerves, iii. 629. 707. Encephalitis^ characters of the urine in, iv. 1291. Encephalocele, or hernia cerebri, i. 744; iii. 719; iv. 954. 95G hydro-encephalocele, iv. 956. of the f^uetus in uiero, ii. 320. Encephaloid czxiccT, characters of, iv. 137. of the lungs, s. 203. of the testicle, iv. 1010. of thyroid gland, iv. 1116. tumours in the muscular substance of the licart, 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 withthatoftheencephalicnerves, 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. 663. table show ing the relative weight of entire body to encephalon, cerebrum, cerebellum, ^cc., iii. 663. conclusions, iii. 6G4. absolute weight of the brain of tlie 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 Tiedeinau deduced from his obser- vations, 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. 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. G70. 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 albicaiitia, iii. 673. crura cerebri, iutercrural space, substantia perforata, pons Tarini, iii. 673. transverse or horizontal fissure, iii. 673. circle of Willis, iii. 673. posterior segment, iii. 073. 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. G74. parts seen in the lateral ventricles, iii. 675. fifth ventricle, iii. 674. fornix, iii. 675. third ventricle, iii. 076. anterior commissure, iii. 677, pineal gland, iii. 677. soft commissure, iij. 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, ancerior 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. arciform, iii. 680. decussating, iii. 680. 776 (iENEKAL INDEX, Encephalon : Medulla oblongata — continued. fissure of, median anterior, ill. 679. posterior, iii. 679. nerves connected with the medulla oblongata, iii. 084. shape of medulla oblongata, iii. G84. transverse sections of the medulla oblongata, iii. 683. Mesocephale, or mesencephale, iii. 684. corpora quadrigemiua, iii. 685. pons Varolii, iii. 685. processus cerebelli ad testes, iii. 686. valve of Vienssens, iii. 686, conclusions, iii. 686. Cerebellum, iii. 687. arbor vitee, lateral and median, iii, 602. castratinn, alleged effects of, on the cerebellum, iii. 687. commissures, iii. 691. long and bidden, iii. 691, short and exposed, iii. 091. single, iii, 691. corpus dentatum, or rhomboideum, iii. 692. crus cenbelli, iii. 692. peduncles of, iii. 693. inferior, iii, 693. middle, iii. 693. supeiior, — processus 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, iii, 687. horizonial, iii. 688. purse-like fissures, or posterior not.h, iii. 688. scmi-Iunar. iii. 687. valley, iii. 687. lamina, iii. 689—691. lobes and lobules, iii. 689. amygdala, iii. 689. 092. biventral, iii. 689. G92. 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 Keil, iii. 691. 692. uses, iii. 691. square lobe, iii. 689. 691. nodule, iii. 690. 693. shape of the cerebellum, iii. 687. .•iections of the cerebellum, iii. 692. horizontal, iii. 692. vertical, iii. 692. si/e ami 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. 70S. mesocephale, iii. 769. cerebrum and cerebellum, iii. 709. brief statement of the probable modus operand! of the brain, iii. 710. Abnormal anatomy of the brain and its membranes, iii. 715. membranes, iii. 715. dura mater, iii, 715. general or partial deficiency, iii. 715. acute disease, iii. 715. causes, iii. 716. 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. Encephalon — continued. ellusions 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. 710. 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. hypereemia, 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 U. cancer of the brain, iii. 720 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. j)arts most frequently affected bv, 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 0. flocks of Ileil, 722 0. 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 cadosum, iii. 723. fornix, iii. 7z3 D. pons Varolii, iii. 723 E. summary of the physiology of the encephalon, iii. 723E. Encepkalosis, or medullary sarcoma of the liver, iii. 193. Encephalous Mollusca, iii. 364. See Mollusca. Encheliadce (rolling animalcules), a family of Polygastiic Animals, iv. 4. characters of the family, iv. 4. Enckelisy or revolving animalcule, iv. 12. Enchondroma. iv. 132. 139, 140. form and colour, iv. 133. progress of, iv. 134. Encrinus., the, lii, 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. Enderon — continued. corpuscula tactus, s. 503. Panician bodies [see also Panician Bogies], 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. Endolymph, ii. 539. Endo~metritis, s. 694. 702. Endo-skeleton of Cephalopoda, i. 519. Endosmosis, 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. Ensijoi-m cartilage, or xiphoid appendix, iv. 1023. Enterocele, ii. 738. ossification of the, iv. 1024. Entcrode.la, a class of Polygastria, iv. 3, et seq. Entero-epiplocele, ii. 738. Enteroplea, a genus of Rotifera, iv. 404. Entomoline, or chitine, ii. 881. chemical composition of, ii. 882. Entomophaga, a tribe of Marsupialia, iii. 259, et scq. characters of the tribe, iii, 259. genera of, iii. 260. Eniomosiraca, ovum of, s. [116.] Entczoa (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, 1 1. 24. cystic Entozoa, s. 2.5. free tapew'orms, 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, h. 111. division into three classes, ii. 111. Protelmintha, ii. 111. Sterelmintha, ii. 111. Ccelelmintha, ii. 111. families of the first class, Protelmintha : — Cercariadte, 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 Rudolph! : — Cystica, ii. 1 15. 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. 1 17. Acephalocystis endogena — Pill-box hydatid, ii. 117. Ascaris Inmbricoides, 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. T®nia 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. 720 E. existence of worms in the intestines of the foetus in utero, ii. 336. in the heart, ii. 647. acarus folliculovum, iii. 730. Gregarinae, process of reproduction in, s. 7. of the human liver, iii. 196. in veins, iv. 1402. Supp. Eolis Farrani, biliary organs of, iv. 449. j Eosphora, a genus of Rotifera, iv. 404. I Ephemera, iii. 539. vulgata, or M.ay-fly, ii. 864. Ephemeridce. or May-flies, ii. 864. characters of the, ii.864. Epkippial process, anterior, or anterior clinoid, i. 726. 728. Ephippium, 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. 602. solar, or coeliac, plexus of nerves, s. 428. veins, deep, iv. 1412. superficial, iv. 1411, 1412. Epigastrium, i. 4. Epigenesis, theory of, ii. 428. See Generation. Epiglottic iii. III. Epiglottis, the, iii. 103. foramina of the, iii. 103. ligaments of the, iii. 104. ligamentum thyro-epiglottideum, iii. 104. hyo-epiglottideum, iii. 104. glosso-epiglottideum.iii. 104. morbid aratomy and pathology of the epiglottis, iii. 122, 123. destruction of the, by ulceration, iii. 1 19. 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 hypercemia in cases of epilepsy, iii. 720 C. dilated state of the ventricles of the brain in old epi- leptics, iii. 720 E. Epiplocete, ii. 738. Epiploic veins, iv. 1414. Epiploic\ effect of, on some of the Mollusca and Insecta, iii. 7. Feathers., structure of, s. 498. the shaft, s. 498. the quill, s. 498. development of, s. 479. formation of the, for flight, iii. 424. See Aves. Fecundation^ phenomena of, ii. 457. circumstances on winch the fecundating property of the seminal fluid depends, ii. 461. course of the seminal fluid within the female organs, ii. 464. difference between the fecundated and unfecundated ovum, ii. 462. nature of the fecundating principle — hypothesis of an aura, &c., ii. 466. relation of the ovum to fecundation by the male sperm, s. [137]. immediate effects of fecundation on the ovum : seg- mentation and first changes of the ovum related to the commencement of embryonic development, s. [138]. changes which the ovum undergoes in the process of, s. 1. See Ovum. is material contact of the semen necessary ? ii. 462. properties of the seminal fluid, ii. 457, 458. seminal fluid, ii. 457 — 4.59. spermatozoa, ii. 459. See Spermatozoa. testicles the only source of fecundating power, ii. 458. general conclusions respecting fecundation, ii. 467. Felidw., organs of voice of the, iv. 1490. Felis Leo, organs of voice of, iv. 1490. Fermented liquor, as an article of diet, ii. 14. Femoral Artery, i. 228. 230 ; ii. 235 ; s. 713. branches, ii. 243. 1. superficial epigastric, ii. 243. 2. external pudic, ii. 244. 3. anterior iliac, ii. 244. 4. profunda femoris, ii. 245. branches, ii. 246. (1.) external circumflex, ii. 246. (2.) internal circumflex, ii. 247. (3.) first perforating arter}*, ii. 248. (4.) second perforating artery, ii. 248, (5.) third perforating artery, ii. 248. (6.) termination of the profunda, or fourth perforating artery, ii. 249. 5. anastomotica magna, or superficial superior in- ternal auricular, ii. 249. other branches, and considerations on the collateral circulation of the thigh, ii. 249. anastomoses of the branches of the femoral artery, ii. 2.50. course and relations of the femoral artery generally, ii.235. course and relations particularly, ii. 237. in its superior portion, ii. 237. in Its second or middle portion, ii. 242. in its inferior portion, ii. 242.. Femoral Artery — continued. femoral canal and femoral sheath, ii. 237. obstructions, effects of, at different points in the course of the artery, ii. 251. operations on the profunda artery, ii. 2.57. operative relations of the femora'l artery, ii. 2i)2. varieties, ii. 243. Femoral canal, ii. 237. 240. nerve, iv. 762. sheath, ii. 237. 240. ring, ii. 757. veins, superficial, ii. 238; iv. 1412. origin and course, iv. 1412. Femur., ii. 165 ; iii. 41. definition, ii. 165. description, ii. 165, 166, interior process of, ii. 166. exterior process of, ii. 166. head of the femur in hip-joint, ii. 777. development, ii. 167. mean measurements, ii. 166. surfaces, ii. 166. structure, ii. 167. femur of man compared with that of the lower Mam- malia, ii. 168. dislocations of the, iii. 721. fractures of the, iii. 67. Fenestra of cochlea, or fenestra rotunda, ii. 533, 543. development of, ii. 559. ovalis s. fenestra vestibuli, ii. 530. 544 ; iv. 546. Fenestrated or striated membrane of veins, iv. 1370. Ferce, Weberian organ in, iv. 1417. 1428. Fer-de-lance (Trigonocephalus), poison fangs of, iv. 291. 888. Fern-chafer., association of the males during the pairing season, iii. 16. Ferns, vegetative system of, s. 239. germination of the spore, s. 239. antheridia, s. 239. archegonia, s. 240. origin of each archegonium, s. 240. the embryo, s. 241. sporangia and spores, s, 241. Ferrein, red and yellow substances of, iii. 181. See Li- ver. Feuillet, psalterium, manyplies, or omasum, of Ruminantia, s. 537. Fever, asthenic, accompanying affections of the larynx, iii. 118. characters of the urine in various forms of, iv. 1289. 1292. haemorrhage into the adipose tissue in, i. 62. rheumatic, or inflammation of the joints, iii. 53. putrid and typhous, condition of the blood after death from, i. 418. 424. tropical, absence of the salts of the blood in, i. 423. appearance of the blood in, i. 424. typhous deposits, iv. 103. analysis of, iv. 104. Fibres of medulla oblongata, antero-posterior, iii. 680. 685. arciform or arched, iii. 680. decussation of, iii, 680. muscular, of the heart, ii. 590. arrangement of the, ii. 619. fatty degeneration in the muscular fibres of the heart, ii. 642. of muscles. See Muscle. Fibrine, ii. 257. analysis of, iv. 162. composition of, iii. 151 ; iv. 165 — 167. average proportion of fibrine in several animal pro- ducts, iv. 165. method of determining the presence of, in organic sub- stances, iii. 795. 805. quantitative analysis of fibrine, iii. 797. fibrine of the blood, i. 410 ; ii. 258. action of acids and alkalies upon, ii. 258. ultimate composition of fibrine, ii. 259. diseased conditions of the, i. 418. muscular fibre, ii. 259. action of acids upon, ii. 259 . 260. fibrine regarded as the plastic element of the nutritive fluids, iii. 743. as an adventitious product in the secretions, iv. 93. fibrinous calculi, iv. 81. fibrinous effusions, iv, 533. vegetable fibrine, iv. 169. Fibro-cartilage, ii. 260. classification of fibro-cartilages, ii. 260. 1. movable fibro-cartilages of articulation, i. 249 ; ii. 260. See Articulation. forms of its connexion w'ith the joints, i. 249. structure of, i. 250. uses, i. 249. 2. fibro-cartilages of tendinous sheaths, ii. 260. See also Articulation. 3. those whose two surfaces are adherent in their entire extent to the bones between which they are placed, ii. 260. chemical composition, ii.261. flexibility, ii. 260. 3 E 3 782 GENERAL INDEX. Fibro-cartilage — continued. microscopic characters, ii. 2G1. cartilaginous corpuscles, ii. 2G1. structures belonging to the class of fibro-cartilages in man and the Mammalia, ii. 2G2. in the inferior Vertebrata, ii. 2G2. morbid conditions of fibro-cartilage, ii. 2G2. See also Cartilage. inflammation and ulceration, ii. 2G2. ossification, ii. 262. substances similar to fibro-cartilages, ii. 2G2. Fibro-cartilages of circumference, or cylindrical fibro-car- tilages, i. 2-19. of hip-joint, ii. 777. interosseous, ii. of knee-joint, iii. 45. interarticular, of the temporo-maxillary articulation, iv. 937. jp/!*ro-cartilaginous laminae of the-vertebr®, i. 250. -cellular matrix of tlie kidney, iv. 239. Fibroma., or adventitious fibrous growths, iv. 130. form and colour, iv. 130. constituents of, iv. 130. Fibrous membrane, elasticity of, ii. 60. concretions in the, iv. 90. membrane of pharynx, iii. 945. 948. polypi of the nose, iii. 740. structures of trachea of man, s. 2GI. system of Bichat, i. 250. Fibrous Tissue, ii. 263. elements of the, i. 127. classes of, ii, 263. I. white fibrous organs, ii. 263 ; iv. 512. absorbents, ii. 263. blood-vessels, ii. 263. chemical properties, ii. 263. nerves, ii. 263. properties, ii. 263. essential properties of each individual class, ii. 264. 1. periosteum, ii. 264. 2. fascise,ii. 264. See Fascia. 3. tendinous sheaths, ii. 264. 4. fibrous coverings, ii. 264. 5. ligaments, ii. 264. 6. tendons, ii. 265. See Muscle. TI. Yellow elastic fibrous organs (tela elastica), ii. 265; iv. 512. organisation and properties, ii. 265. morbid anatomy, ii. 266. 1. inflammation, ii. 266. II. cartilaginous transformation and ossification, ii. 266. III. fungus, ii. 266. IV. osteo-sarcoma, ii. 267. See Serous and Synovial Membranes. contractile fibrous tissue of penis, iii. 913. induration of fibrous tissue, iv. 713. adventitious formation of fibrous tissue, iv. 141. Fibula, i. 151 ; ii. 170. development, ii. 171. extremities, ii. 170, 171. form and size, ii. 170, structure, ii. 171. surfaces, ii, 170. fibula of man compared with that of the lower Mam- malia, ii. 171 . fractures of the, i. 156 ; iii. 135, 136. difficulty of preserving its proper position in frac- tures of, iii. 135. amputations of the leg, iii. 134. Fjbular Artery (arteria peronea), ii. 267. absence, ii. 267. branches, ii. 267. anterior peroneal, ii. 267. posterior peroneal, ii. 267. origin and position, ii. 267. relations to operation, ii. 268. Fifth Pair of Nerves (trigeminal or trifacial nerve), in human anatomy, ii. 268. general .structure and encephalic connexions in man, ii. 268. in inferior animals, Ii. 275._ external, or extracephalic portion of the nerve, ii. 278. divisions, ii. 279. first or ophthalmic division, ii. 279. branches, ii. 279. recurrent branch of first division, n. 279. 1. frontal nerve, ii. 270. 2. nasal nerve, ii. 281 . 3. lachrymal nerve, ii. 282. second division, or superior maxillary nerve, ii. 283. branches, ii. 284. 1. temporo-malar, ii. 284, 2. spheno-palatine, ii. 284. 3. spheno-palatine ganglion, organglion of Meckel, ii. 285. 4. dental, posterior superior, ii. 289. anterior superior, ii. 289. 5. facial branches, ii. 289. Fifth Pair of Nerves— third division, or inferior maxillary nerve, ii. 290. branches, ii. 291. 1. masseteric, ii. 291. 2. deep temporals, ii. 291. 3. buccal, ii. 291. 4. pterygoid, ii. 291. 5. otic or auricular ganglion of Arnold, ii. 292. 6. sui>erficial temporals, ii. 293. 7. inferior maxillary or dental, ii. 294. 8. lingual, ii. 29.5; iv, 1141. 9. chorda tympani, ii. 295, 10. sub-maxillary ganglion, ii. 297. ganglion of the fifth nerve (ganglion semilunare Gas- seri), ii. 298. vital properties of the fifth pair of nerves, ii. 299. 1. sensibility, ii. 299. 2. influence upon sensation and volition, ii. 299. Bell’s experiments, ii. 299. Majendie’s experiments, ii. 300. Mayo’s experiments, ii. 300. 3. relation to the special senses, ii, 305. (1.) smell, ii. 305. (2.) vision, ii. 307. (3.) hearing, ii. 3U9. 4. influence upon the nutrition of the parts to which it IS distributed, ii. 309. progression, ii. 315. 5. influence of disease on the functions of the nerve, ii. 316. anastomoses of branches of the ninth with branches of the fifth, iii. 722. Fifth ventricle of the brain, iii. G74. 704. Filaria bronchialis, ii. 122, 123. description of the, ii. 123. oculi humani, li. 122. described, ii. 122. Medinensis, or Guinea-worm, i. 517 ; ii. 122. endemic in the tropics, ii. 122. generation of Filarise, ii. 143. parts of the body affected by it, ii, 122- size and form, ii. 122. organs of digestion of Filaria, s. 296. File-fish, iii. 977. termination of the pia mater (filum terminale), iii. 633. Filtration of organic substances, iii. 795. method of performing, iii, 795. Fi?nbri physical properties, ii. 17 ; s. 329 specific gravity, s. 329. quantity, s. 330. chemical composition, ii. 17, 18; s. 330. gastric acid, s. 330. saline constituents, s. 330. organic substance, or pepsine, s. 330. chemical properties of pepsine, s. 333. antiseptic power, ii. 18. property of coagulating albumen, ii. 18, solvent power, ii. 18. action of the gastric juice, s. 333. peptone, s. 334. nature of the action, s. 336. process by which the gastric juice is secreted, s. 337. Gastric juice — continued* digestion of food, process of, s. 398. effect of mental emotions on the secretion of, iv. 466. effects of the lesion of the vagi upon the, iii. 900, Gastric artery, s. 325. branches of the nervus vagus, iii. 899. veins, iv. 1414. Gastritis, acute, appearances of the stomach in, s. 414. Gastrocnemius muscles, ii. 357 ; iii. 127. 132. I3S ; iv. 62. relations, iii. 138. omentum. See Omentum, great. ‘duudenalis artery, s. 326. ^enteritis, i. 797. ^epiploic ’a\'X.%xy, i. 194, 195. dextra, iii. 942 ; s. 326. sinistra, iii. 942 ; s. 327. vein, s. 381. right, s. 327. lelt, s. 327. -hepatic, or small, omentum, s. 309. ^intestinal calculi, iv. -lineale ligamentum, iv. 771. Gaslro^nele, iv. 969. G astro-pulmonary tract of the mucous system of man, iii. 495. -splenic omentum, s. 309. Geaster fimbriatus, receptacle of, s. 225. Gecko, organs and mode of progression of the, iii. 449. Gechotidcc, a family of Reptilia, iv. 265, et seq. Gelatin, ii. 404. characters of, ii. 405. chloride of, ii. 405. combination of gelatin and tannin, — tanning leather, ii. 416. definition, ii. 406. ultimate composition of gelatin, ii. 40G. gelatin in bones, i..437. Gelatiivjorm cancer of the liver, iii. 193. Gelatinous adhesion, ii. 742. nervous fibres, iii. 599. polypi of the nose, iii. 740. ti&sues, analyses of, iii. 806. cortex of sponges, iv. 67. Gelatino.7uucous secretion in the vagina in Marsupialia, iii. 318. Gemellus inferior muscle, s. 138. superior muscle, s. 138. muscles, nerves for, iv. 767. Gemmee, or buds, of Polypifera, which see. Gt'77imati07i, or budding, process of, as a mode of repro- duction, s. .5. 211. Gemmiparous generation, ii. 407. 433; s. 5. external, i. 145. internal, i. 145. See Generation; Generation, Organs of. Generation (in human and comparative anatomy), organs and means of, ii. 406. fissiparous generation, ii. 407. gemmiparous generation, i. 145 ; ii. 407. 453 ; s. 5. 21 1 . oviparous generation, ii, 407. 1st Division. — Animals in which ovigerous organs only have been clearly recognised, ii. 409. 2d Division. — Animals provided with ovigerous organs combined with an additional se- creting structure, probably subservient to the fertilisation of the ova, ii. 410. 3d Division — Ovigerous and impregnating or- gans co-existent, but the co-operation of two individuals necessary for mutual impregna- tion, ii. 411. 4th Division, — Sexes distinct; that is, the ovi- gerous and impregnating organs placed in separate individuals, ii, 412. Insects, ii. 413. See Insecta. Arachiiida, ii. 413. See Arachnida. Crustacea, ii. 417. See Crustacea. Mollusca, ii. 4l7. See Mollusca. Vertebrate Ovipara, ii. 418. Fishes, ii. 418. See Pisces. Reptiles, ii. 419. See Reptilia. Birds, ii. 421. See Aves. Mammalia, ii. 421, See Mamm.^lia. accessory vesicles, ii. 423. Cowper’s glands, ii. 422. penis, structure of, iii. 423. prostate gland, ii. 422. testes, ii. 422. organs of, in infancy, i. 73. first steps in the process of impregnation, s. 608. muscles of the, iii. 544. muscles acting on the genitals, s. 138. female external organs of generation, s. 708. normal anatomy, s. 708. the mons veneris, s, 708. labia, s. 708. clitoris, s. 709. nymphae, s. 710. vestibule, s. 710. vaginal orifice and hymen, s. 710. origin, varieties, and siguification of the hymen, s 710. 788 GENERAL INDEX. Generation, female external argava—confinucd . sebaceous and muciparous glands and follicles of the vulva; vulvo-vaginal glands, s. 711. bulb of tlie vagina; pars intermedia; con- strictor vaginze, s. 712. blood-vessels and nerves of the external or- gans, s. 713. abnormal anatomy, — labia, s. 714. clitoris, s. 714. nymphte and vestibule, s. 714. hymen and ostium vagin®, s. 715. abnormal conditions of the, in cases of hermaphrodit- ism. See Hermaphroditism. Generation (in physiology), ii. 424. definition, 421. I. Function of reproduction generally considered, ii. 42G. 1. introductory remarks, ii. 42fi. 2. theories of generation, ii. 427. epigenesis and evolution, ii. 428. 3. spontaneous generation of animals, ii. 429. II. Sketch of the principal forms of the| reproductive functions in different animals, ii. 432. 1. non-sexual reproduction, li. 432. s. 2. 5. three forms of, s. 2, 3. fissiparous generation, ii. 432. gemmiparoiis generation, ii. 433. reproduction by separated buds or sporules, ii. 433. of the process of reproduction in Protozoa, or animals in which the sexual distinction has not yet been discovered, s. 6. of the possibility of primary, direct, or non-pa- rental production of animals, or of so-called spontaneous and equivocal generation, s. 9. production of dissimilar individuals among sexual animals by a non-sexual process: so-called “ alternate generations,” s. 12. embryological development, s. 12. metamorphoses, s. 12. metagenesis, s. 13. 3S. larva, s. 13. alternating reproduction of — Evhinodermata, s. 14. Polypina, s. IG. Acalephae, s. 20. Mollusca, s 22. Salpidse, s. 23. Entozoa, s. 24. cystic Entozoa, s. 2.'S. free tapeworms, s. 27. Trematoda, s. 29. Annelida, s. 32. Insecta: Aphides, s. 33. general remarks on alternate generations, s. 13. 34. the ” nurse ” of Steenslrup, s. 37- parthenogenesis, s. 37. 2. Sexual reproduction, ii. 434. nature of tlie ovum, ii. 434. ovum in general as related to the sexual process of generation, s. 3. essential conditions and phenomena of the sexual mode of generation, s. 4. relation of the ovum to fecundation by the male sperm, s. [137.] action of the spermatozoa on the contents of the egg, s. [137,] [138.] hermaphrodite generation, ii. 434. dioecious reproduction, or with distinct in- dividuals of different sexes, — oviparous and viviparous generation, ii. 435. See also Ovu M. varieties in respect to utero-gestation and the development of the young, ii. 43G. Marsupiate generation, ii. 43G. Monotrematous generation, ii. 437. comparison of animal aud vegetalde reproduc- tion, ii. 437. synoptical table of the various forms of the reproductive process, ii. 438. HI. Reproductive functions in man and higher animals, ii. 438. sketch of this function in man, ii. 438. See Ovum ; Uterus and its Appendages. organs of reproduction, ii. 438. puberty, ii. 439. structural differences of the sexes, ii. 439. menstruation, ii. 439. See Menstruation. periodical heat in animals, ii. 441. age at which puberty occurs, ii. 441. period during which the generative function is exercised, ii. 442. variations in the lower animals, ii. 442. effects of castration, ii. 443. sexual feeling, ii. 443. relation of reproduction to the brain, ii. 444. Gall’s views of the connexion of the cere- bellum with the sexual functions, iii. 722 S. Generation, reproductive functions — continued. distinction of species — mules, ii. 344. functions of external organs of reproduction, ii. 445. erection, ii. 445. IV. Changes consequent on fruitful sexual union, ii. 447. 1. As regards the female chiefly. — Conception. ii. 447. turgescence of the generative organs after conception, iii. 447. approximation of the fimbriated extremities of the Fallopian tubes to the ovary, ii. 447. changes in the ovary ; bursting of the Graafian vesicles, ii. 448. formation of the corpus luteum, ii. 449. descent of the ovum. — Its structure and changes during its passage, ii. 45). time at which the ovum arrives in the ute- rus, ii. 453. change in the uterus after conception, ii. 454. irregularities in the descent of the ovum, ii. 455. circumstances influencing liability to concep- tion, ii. 456. signs of recent conception in women, ii. 457. office of the uterus in insemination, s. 671. See Uterus. office of the uterus in gestation, s. G72. gestation in Fallopian tube, s. 620. varieties of, s. G21 . 2. As regards the male, ii. 457. fecundation, ii, 4.57. properties of the seminal fluid, ii. 457. chemical properties, ii. 458. spermatic animalcules, ii. 459. table of their sizes in different animals, ii. 4C0. See also Semen. circumstances on which the fecundating property of the seminal fluid depends, ii. 461 . difference between the fecundated and unfecundated ovum, ii. 462. is material contact of the semen and ovum necessary ? ii. 462. external and artificial fecundation, ii. 462. course of the seminal fluid within the female organs, ii. 464. nature of the fecundating principle. — Hypothesis of an aura, &c., ii. 466. general conclusions respecting fecunda- tion, ii. 467. V. Miscellaneous topics relating to the preceding history of generation, ii. 468. 1. superl'oetation, ii. 469. 2. influence exerted by parents on the qualities of their offspring, ii. 470. 3. number of children and relative proportion of the male and female sexes, ii. 478. causes of variation of sex, ii. 479. table of the proportion of males to females born in different countries, ii. 478. See also Ovum ; Uterus and its Appendages. Gestation. See Generation ; Ovum; Uterus and its Appendages. Genial processes, ii. 214. Genicular nerve, internal, ii. 241, Geniculate bodies, iii. 700. external, iii. 700. internal, iii. 700. their relation to the optic nerves, iii. 768. ganglion, iv. 549, 550. muscle, iv. 1125. 1133. action and relations, iv. 1133. Genio-h?/o-glossus muscle, iii. 565. action and relations, iii. 565. GcnioJiyoideus muscle, iii, 105. 565. action and relations, iii. 565. Gcnito-crural nerve, ii. 838 ; iv. 761, 762. crural branch, iv. 762. Genito-urinary organs, motor influence of the sympatheiic nerve in reference to the, s. 466. Genito-urinary tract of the mucous membrane of man, iik 495. 497. Geodvphaga, or ground-beetles, ii. 859. characters of the sub-tribe, ii. 859. Geodia^ a family of Porifera, iv. 65. characters of the family, iv. 65. GeometrcB, organs and singular mode of progression of the, iii. 442. Gcomys bursarius, or Canada rat, iv. 386. Georgian nation, changes in the anatomical conformation of, iv. 1328, 1329. Gcotrupes stercorarius, or dung-beetle, ii. 860. nervous system of, iii. 610. Gerbilles, anatomy of, iv. 371, seq. frcr?«-mass, blastoderm, or germinal membrane, s. 4. vesicle, or germ-cell, of ovum, s. 3. 70. [87.] [133.] ii. 452. See Generation ; Ovum. GENERAL INDEX. 789 Gerontoloxon, or arcus senilis, i. 80. Gibbons, iv. 195, et seq. See Quadrumana. organs of voice of the, iv. 1487. Giddiness of anaemic patients, iii, 723 C, mode of treatment of, iii. 723 C. Gills, or branchiae, iv. 331. of Amphihiae, s. 278. of Fishes, i. 646. Gimbernat's ligament, i. 5 ; s. 137. Ginglunius^ angular and lateral, i. 256. Giraffe^ anatomy of the, s. 508, et seq. cranium of, s. 510. 516. horns of, s. 516. skeleton of the, s. 520, brain of, s. 542. intestine of, s. 539. organs and mode oflocomotion of the, iii. 454, pelvis of the, s. 15S. tongue of the, s. 533. Gi^xard of birds, i. 320. See Aves. functions of, ii. 11, 12. structure of, s. 301. Glabella, i. 729. Gland, ii. 480. definition, ii. 480 development, ii. 492 ; iv. 455. divisions and kinds of glands, ii. 481. organisation, ii. 481 ; iv. 455. blood-vessels, ii. 487. arrangement of their minute subdivisions, ii. 488. excretory ducts, ii. 486. interstitial cellular tissue, ii. 489. investing membrane, ii. 489. lymphatic vessels, ii. 489. minute structure of glands, ii. 481. simple forms, ii. 482. complex forms, ii. 483. nerves of glands, ii. 489. See Secretion. secreting canals and excretory ducts, ii. 486. situation of glands, ii. 481. See Kidney; Lachrymal Organs; Liver; Pancreas. Gland, Cowper’s, ii. 422. in Man and In other animals, ii. 422. lachrymal, iii. 88. 784. inferior, iii. 89. parotid, iii. 581. 902 ; iv. 423. relations, iii. 902. pineal, iii. G76, 077. prostate, ii. 422 ; iii, 932 ; iv. 146. See Prostate Gland. relations, size, and density, iii. 933. capsule, iii. 933. vesico-prostatic plexus of veins, iii. 933. prostatic diseases, iii. 934. sublingual, ii, 214 ; iv. 424. submaxillary, iv. 424. thymus, iv. 1087. functions of the, iv. 445. thyroid, iv. 1 102. functions of the, iv. 445. Ghmds, absorbent. See Lymphatic and Lacteal System. axillary lymphatic, iii. 231. of Brunn, or racemose glands, s. 361, 362. buccal, iv. 426. ceruminous, ii. 553. conglobate, of Sylvius. See Lymphatic and Lacteal System. Cowper's, iii. 930; iv. 1247. 12-52. duodenal, s. 361, 362. Haversian, i. 253 ; ii. 777, 778. hypogastric, or internal iliac, i. 387. labial, iv. 426. of the larynx, iii. 110. arytenoid gland, iii. 110. epiglottic, iii. 111. lenticular of the stomach, s. 324. ofLittre or Morgagni, iv. 1250. lingual, anterior, iv. 426. posterior, iv. 426. lymphatic. vSee Lymphatic and Lacteal System. lymphatic, axillary, i. 368. cervical, i. 368. inguinal, 1. 368. mammary, ii. 481. Meibomian, iii. 81, 82. mesenteric, iii. 943. molar, iv. 426. mucous, of tongue, iv. 1140. of nipple, iii. 246. oesophageal, iii. 7-59. of Pacchioni, i. 729. 735. palatine, iv. 426. pancreas, s. 81. parotid, ii. 481. racemose, or glands of Brunn, s. 361, 362. salivary, iv. 422. subsidiary, iv. 425. sebaceous, of eyelids, iii. 82. sebaceous and muciparous, and follicles of the vulva, s. 711. sudoriparous, s. 499. Glands -‘Continued. superficial inguinal, ii. 238. teguinentary, s. 499. tracheal, s. 260, 261. secretion of, s. 261. testes, ii. 481. utricular, or follicles of uterus, s. G3C. viilvo-vaginal, s. 712. Glandula innominata, iii. 88. GlanduUe concatenatae, iii. 577. cougregatae, iii. 89. Pacchioni, or cerebral granulations, iii. 629. 631. description of tliem, iii. 644. are they natural structures ? iii, 645. suprarenales, sen renes succenturiati. See Supra- renal Capsules. Tysoni (odoriferae), iii. 914. Glandule of Harder, iii, 98. in Mammalia, iii. 98. in Birds, iii. 93. in Reptiles, iii. 98. secretion of the, iii. 98. Glandules of breasts, iii, 248, Gians clitoridis, s. 709. t^-xture of which it is composed, ii. 446. penis, ii. 424 ; iii. 914 ; iv. 985. corona glandis, iii. 914. glandulcB Tysoni (' doriferae), iii. 914. meatus urinarius, iii. 914. microscopic anatomy of the glans penis, iii. 914. Glasserian fissure, i. 733. 735 ; ii. 545, Gtauco^na, or pearl animalcules, ii. 192; iv. 13. Glejio-humeraly 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. 168. ligament, ii. 157; iv. 573. carpal anterior, ii. 508. posterior, ii. 608. of metacarpo-phalangeal joints, ii. 510, Glenophora, a genus of Rotifera, iv. 401, et seq, Gliduig motion of joints, i. 2.'6. Glisson's capsule, lii. 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, iii. 484. distinction of the pus and mucus, iii. 484. Globuline of M. Lecanu, i. 41 1. 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. Glossantkrax, or malignant pustule of the tongue, iv. 1156. Glossitis, erectile, iv. 1153. suppurative, iv. 1153. mercurial, iv. 1 154. Glosso-epiglottid io\ds, m. Ill ; iv. 1121. ligament, iii. 104. Glosso-pharyngeal nerve, i. 732 ; ii. 49-1 ; 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. 407 — 500 ; iv. 500. Glosso-staphylinus muscle, iii. 952; iv. 1132. action and relations, iv. 1133. Glottic 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. Glut.ral Region (in surgical anatomy), ii. .500. arteries, ii. 501, 502. boundaries, ii. 500. definition, ii. 500. muscles, nerves, and veins, ii. 501, 502. Glutceal artery, ii. 250. 833. course and distribution, ii. 833. impression, s. 1 15. muscle, maxiraus, i. 61. 177; ii. 166. 501. 833; s. 115. 137. medius, ii. 500—502. 833 ; s. 1.37. minimus, ii. 501, 502. 833; s. 137. 790 GENERAL INDEX. G luta*al —coni inucd. nerve, stiperior, iv. 766. branches, iv. 766. inferior, iv. 7GG. veins, iv. 1412. Gluten, nutritive properties of, ii. 13. Gli/crrine in the brain, iii. .'?8S aciileatum. a parasitic worm, ii. 134. accessory glands of the digestive system of, ii. 130. Gnats (('ulicidae), ii. 8G7 ; iii. 539. societies of, iii. 16. emigration of societies ofthe larvse of, iii. 16. Goats, anatomical characters of, s. 508, et scq. 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 orjan of the, iv. 1420, 1421. 1428. Ooat-suc/ie7\eir night-jar, habits of, iv. 679. Gobidae, a family of Fishes, iii. 957. Cto//;'C, or hronchocele, iii. -575. danger of operations for the extirpation of tumour in, iii. .576. treatment with iodine, iii. 576. goitre hereditary, iii. 471. (Fringilla carduelis), nervous system of the, iii. 622. Gomphosis, form of articulation, i. 25.5. Gonidia of lichens, s, 227. Gonium pectorale, mode of propagation of. ii. 407. puivinatnm, mode of generation of, ii. 407. Gono7‘7-hcea,\\. 12.58; s. 707. pathological changes in the urethra from this disease, iv. 12.58. chordee, iv. 1258. hernia humoralis, iv. 12.58. co-existence of, with chancre, iv. 1258. consequences of this affection, iv. 1258. Goose (Anas anser). pancreas of the, s. 96. Goi'dins, or hair-worm, muscles of the, iii. .538. formation of the ova and fecundation of, s. [123.] Goi’gonia nohilis. iv. 31. umbraculum, iv. 30. veriucosa, iv. .32. ova of, s. [127.] luminousness of, iii. 198. Gorgonocepfiali, 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. Granfiari vesicles, or follicles, s. 56. [81.] structure of, s. 550. form, s. 5.50. 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. 655. 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. Grallatoi‘es, or wading birds, characters of, i. 269. mode of flight of the, iii. 429. pelvis of the, s. 169. Gramdnr excrescences on the valves of the aorta, i. 191. Granulation of fractured bones, theory of, i. 446. 602, 603. See Cicatrix. development of, i. 52. Granulation, semi-transparent grey, iv. 105. Granulations, cerebral. See GlandaUe Pacchioni. Granules of chyle, iii. 221. osseous, iii. 848. See Osseous Tissue. Grasshopper, powers of leaping of the, iii. 47 1. 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, ofthe 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. animals. See Congregation; 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 of form of the elements of grey nervou.s matter, iii. 649. ])igrnent, iii. 647. 649. See Nervous Centres. GriffWisin, antheridium of, s.221, 222. Grom, region of tlie, i. 4, 5. Groin, Region of the (in surgical anatomy), ii. 503. See Abdomen; Fi-moral Artery; Hernia. Groove, infra-orhitar, 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-))ubic, or obturator, s. 116. Gj’ooves of palate bones, ii. 21J. of ribs, iv. 1031. Gi-ound~beet\es, ii. 859. Growth of man, i. 65. Growths, malignant, method of performing tlie analysis of, iii. 806. in the oesophagus, iii. 761. GryUotalpa 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. domesticLis, or house-cricket, mode of flight of the, iii. 421. powers of leaping ofthe, iii. 474. Gi'ypoj’hynchus pusilUis, a parasitic worm, ii. 127. Guanches of the Canary Islands, language of the, iv. 1357. Guber of Sudan, characters of the, iv. 1352. Guhcrnnculum testis, i. 7 ; iv. 982. Guinea-pig (Cavia), anatomy of the. iv. 372, et scq. 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 (gingivie), iii. 951. See also Palatine Arch, vessels and nerves of the gum.s, 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 Cwcum. great, s. 365. See Colon, straight, s. 368. See Reciuin. See also Stomach and Intestine. Guthrie's muscles, iii. 930; iv. 1264. Gymnica, a section of Polygastric animals, iii. 5. (iymnndontes, a family of Fishes, iii. 957, et seq. Gymnogramma chrysophylla, prothallium of, s. 240. Gymnoius 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. Gyrodactijlus auriculatus, a cestoid parasitic worm, i . 130. H. liabcncc, 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, H. of Reptiles, ii. 649. of Fishes, ii. 649. of Insects, ii. 650. 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 of internal parts, ii. 654. relations in point of temperature between external parts, ii. 655. difference of temperature according to dej'th, 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. <>73, influence of temperature on the vitality of warm- blooded animals, and of man, in the states of health and disease, ii. 674. effecls of various other causes of modification in ex- ternal agents, ii. 680. means for etlecting 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. G81. sudden transitions of, ii, 68l. bloodletting, ii. 681. diaphoretics and purgatives, ii. 682. diet and regimen, ii. 682. 3 F 79-t GENERAL INDEX. Heat, Animal — continued. means lor eftecting an increase of animal heat, ii. GH2. quinia, ii. 682. confirmation of general results, ii- 6S2. of t"e physical cause of animal heat, ii. G83. 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. 721 S. impaired evolution of heat during the sleep of hiber- nating animals, ii.7G7. influence of diflerent media upon temperature, ii. 659. effects of external temperature upon an isolated part of the body, ii. 660. eflects of partial co iling, 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 tlie bodily temperature differs from that of the adult age, ii. 663. 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 presenti-d by hibern.iting 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 ainmals which are born blind when removed from the contact of their parents, li. 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 ( Erinacead®), ii. 994. muscular and spiny covering of the hedgehog, ii. 999. uses of, ii. 1004, 1005. structure of the sjnnes of the, s.498. [)elvis of the, s. 164. hibernation of the, ii. 764. See Hibernation. Hi cl-bonc, or os calcis, ii. 339. Height of the human body at different ages, i. 74. Hchmys (Cape jerboa, or jumping hare), anatomy of the, iv. 372, et scq. Helix, ii. 5.50, 551. helicis major muscle, ii. 552. minor muscle, ii. 552. Helix albolabris, biliary organs of, iv, 443. pomatia, generative process of, ii. 397, 398. spermatozoa in the, ii. 113 ; iv. 486. J-Llocera, a tribe of Coleoptera, ii. 860. characters of the tribe, ii. 860. Hcmadyriamonietery of Poiseuille, i. 662. HcmcroUidcE, or lace-winged flies, ii. 865. Hemicephalia, iv. 954. See Acrania. Hejnielliptical fovea, ii. 530. Hemiplegia, iii 37 — 40. effects of galvanism in cases of, iii 38. 41. Hemiptera, an order of Insecta, ii. 868. characters of the order, ii. S68. nervous system of the, iii. 610. Hemispheres of the brain, iii. 078. 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. 320. 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 plexus, iii, 169. interlobular ducts, iii. 169. lobular ducts and lobular plexus, iii. 169. termination of tlie biliary ducts, iii. 170. vascularity of the biliary ducts, iii. 170. mucous membrane and follicles of the biliary ducts, iii. 171. See also Liver. Hepatic y\Qyi\x% of nerves, iii. 174; iv. 1414; s. 429. trunks, iii. 173. veins, iii 172 ; iv. 1414. inb'rlobular veins, iii, 173. sub-lobular veins, lii. 173. hepatic trunks, id. 173. venous canals, iii. 173. llcpaficce, vegetative system among tlie lower, s. 232. first period — from the germination of the spore, s. 233. development of the antheridia, s. 233. of the arcliegonia, 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, s. 234. Ilepatico-duodenal ligaments, s. 341. Hepatitis, lobular, id. 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 physical, phenomena of the transmission of, from parent to offspring, ii. 471. IlERMAPnuoDmsM, Or llermaphrodism, ii. 684. classification of hermaphroditic malform.itions, ii» 685. I. Spurious hermaphroditism, ii. 685. A. in the female, ii. 685, 1. abnormal development or magnitude of the clitoris, ii. 68G. in some of tlie lower animals, ii, 689. 2. prolapsus uteri, ii. 690. B. 'in the male, ii. 690. 1. extroversion of the urinary bladder, ii, GDI. 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, perineum, &c., ii. 691 in some of the lower animals, ii. 695. II. True hermaphroditisin, ii. 695. A. lateral hermaphroditism, ii, 696. 1. ovary on the leftside and testes on the right, ii. 698. 2. testicle on the left and ovary on the right, ii. 700. B. transverse hermaphroditism, ii. 701. J. 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 vesicul® semiuales, kc.., superadded to organs of the female sexual type, ii. 707. 2. imperfect female uterus, &c., superadded to a sexual organisaiion essentially male, ii. 707. 3. Co-existence of female ovaries and male testicles, ii. 711. two testicles and one ovary, li. 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-existeuco of a female uterus with ttsticles and other organ of a male sexual type, ii. 730. 3. fallacies in tlie supposed co-existence of tes- ticles and ovaries, ii. 731. physiological degree of sexual perfection in herma- phrodites, i. 14-5; ii. 434. 732. causes of hermaphroditic malformations, ii. 733. hermaphroditism in double monsters, ii. 736. See also Teratology. llermclla, ovum of, s. [117,] [118.] Hermit-crab, nervous system of the, iii. 613. Hernia (morbid anatomy), ii 73S; s. 405. circumstances under which protrusions of the abdr*- minal viscera take place, varieties, &c., ii. 738. enterocele, epiploce!e,and entero-epipiocele, ii. 738. arrangement of herni®, ii. 741. irreducible hernia, ii. 741. 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. 745. effect of strangulaiion on the viscera within the cavity of the abdf>men, ii. 745. symptoms and progress, ii. 745. congenital hernia, ii. 740. crural or femoral hernia, ii. 756. affection.^ which may be confounded with it, ii. 7G0. symptoms and progress of the disease, ii. 759. definition, ii. 738. hernial sac, ii. 738. GENERAL INDEX. 79o Hernia — 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 from oblique hernia, ii. 756. umbilical hernia, ii. 761. congenital, ii. 761. of more advanced periods of life, ii. 762, 763 symptoms, ii. 764. Heinia in particular: — cerebri, or encephalocele. iii. 719; iv. 141. 954. 956. of the foetus in iitero, ii. 320. 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. inlercolumnal bands in old herniae, i. 5. of ovary, s. 574. perineal, 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 urinary bladder, i. 395. at the crural ring, i. 396. at the perineum, i, 396, through the vagina, i. 396. of ihe uterus, s. 684. ventral, congenital, iv. 950. Hernial tumours of the glutaeal region, ii. 502. Herophilus^ press of, iii. 63). Herring^ an inhabitant of the arctic seas, iii. 13. mode of migrating in shoals, iii. 13. eyes of, iii. 1002. pyloric caeca of the, s. 94. tongue ol the, iv. 1146. Hi-tcradelphi, iv. 968. Hclerogangliatay a division of Mollusca, iii. 364. muscular system in the, iii. 540. Heteromera^ a section of the order Coleoptera, ii. 863. characters of the section, ii. 863. Hexaprotodony an extinct genus of Pachydermata, which see. 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. 1, Of sleep, ii, 776. II. Of the sleep of liibernating 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. 263 ; ii. 768. condition of the several functions in hibernation, ii. 768. circulation, ii. 771. defascation, ii. 768. 772. 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. 15.3. methods adopted by hibernating animals for secu- ring themselves from disturbance and excite- ment, ii. 774 ; iii. 12. IV. Of revivescence, ii. 774. V. Of torpor from cold, ii. 775. difference between torpor and hibernation, ii. 775. See also Irritability. difference between simple sleep and hibernation, iv. 678. Hibernating ova, s. [117.] [127], [12S], See Ovum. of Rotifera, s. [U9]. Hibernation of plants, iii. 1.57. Hiluyn of the kidney, iv. 234. Hihis lienalis, iv.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. 778. 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. 1. 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 synovial membrane and other structures, ii. 787. arthritis coxae acute, ii. 790. anatomical characters, ii. 792. cases, ii. 790, 791. arthritic cox«, chronic strumous, ii. 793. anatomical characters, ii. 795 cases, ii. 795, 796. arthritic cox®, chronic rheumatic— morbus coxae senilis, — chronic rMeuraatij-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. 78S. “ diffuse ” inflammation, case of, ii. 783. synovitis cox® with periostitis, ii. 788. symptoms of the early stages of 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, ii, 802. A. fracture of its fundus, ii. 802. post mortem examination of a case, ii. 803. B. fracture of its brim, ii. 803. 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- plicat-’d 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. b. dislocation backwards or towards the ischiatic notch, ii. 818. anatomical characters, ii. 820. c. dislocation upwards and inwards on the pubes, 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 of the head of the femur, ii. 824, upwards and outwards, ii. 824. downwards and backwards, ii. 824, Hippobosca equina, or forest-fly, ii. 867. Hippocampus, iii. 986. Hippoca7Upus major (or cornu Ammonis), iii. 675. 693. minor (or ergot), iii. 675. 698. 3 F 2 796 GENERAL INDEX. Il/ppomanes, iv. 74-J. JJ/ppupo(amus, anatom}' of tlie, iii. 8G0, cl scq. See Pachy- DERMATA. stomach of the, s. 303. pelvis of the, s. 156. Ilippun'c, or urobenzoic, acid, iii. 800. analysis of, iii. 800 ; iv. 1270. in diseased urine, iv. 1283. presence of, in the blood, iv. 400. JUppuris vulgaris, development of, s. 240. ll/rcic acid, ii. 233 ; iii. 362. llirciTis ii. 233. Jlirudhtes, (or leeches), organs and mode of progression of the, iii. 441. ovum of, s. [117.] llirudiuvicB^ eyes of the, i. 167. respiration of the, i. 171. IJoarscncss and loss of voice, causes of, iii. 123. ilog^ parasites in the muscles of the, ii. 120. pelvis of the, s, 156. teeth of the, iv. 905. Jlolloiuoi the sacrum, s, 127. Uoluphrya, or woolly animalcule, iv. 13. Ilolothuria, i. 109 ; ii. 31. lloluthuria tubulosa, ova of, s. [12.5]. Muller’s discovery of the micropyle ai>erture, s. [125]. nervous filaments of (?), iii. 602. muscles of the, iii. 537. generative system of, ii. 410. alimentary canal of, s. 297. See liCHINODEUMATA. llomalopleray an order of Insecta, ii. 867. characters of the order, ii. 867. Homogangliata, iii. 537. muscular system of the, iii. 538. llomogany^Uate nervous system of the Articulata. See Articulata. llomop/era, an order of Iiisecta, H. 868. characters of the order, ii. 868. Ihmcy^ method used by collectors of honey to discover bees’ nests, iii. 423. Hood, or head-cowl, of Pteropoda, iv. 174. Hoofs, structure of, iv. 437 ; s. 477. of horses. See Solipeda. of Ruminants, s. 531. object of the cloven foot, s. .531. Hooked worms, ii. IIG. See Entozoa. Hordeohn)}, or stye, iii. 83. Hornets (Vcspidi), habits of, ii. 865. their habitations, iii. 11. Horns, sacral, s. 119. Horyis of thyroid cartilage, iii. 102. Horny tissue of animals, i. I i7. “ Horns," or adventitious Iiorny matter, iv. 139. Horiis of Ruminantia, structure of, s. 47><. 516. Horse, anatomy of the, iv. 715. See Solipeda. stomach and intestines of the, s. 303. M^eberian organ of the, iv. 1419. causes of “ roaring ” t. superior curved line of the, s. 1 14. Imago, the, or perfect state of insects, ii. 880. Imbecilihj preceding death, i. 799. Impression , deltoid, iv. 571. gluteal, s. 115. Impulse of the heart, ii. 604, Inanition, syncope by, i. 797. Incident nerves, iii. 720 II . 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. majoris, s. Santorini, muscle, ii 553, semilunaris, lunula (coracoitl process), ii. 156. Incubation See Ovum. instincts guiding, of birds, iii. 14. Crustacea, i. 785. Incubus, or night-mare, iv. GS8. Incus, or anvil-bone, ii. 516. development, ii. 560. abnormal conditions, ii. 561. hidia, variety in the complexion of the different races of, iv. 1336, 1337. Indian Arcliipelago, inhabitants of the, iv. 1363. elephants, iii. 858. See Pacuvdermata. ink, the Cliinese pigment so called, i. 536. Indicator^ or extensor proprius primi digiti manus, muscle, ii. 370. 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. Inferobranchiata, ii. 377. See Gasteropoda. /7//;-rt-clavicular nerves, iv. 755. J///rrt-costaies muscles, iv. 1056. action, iv. 1056. /w/;-rt!-maxillary nerve, iv. 548. ////m-orbital artery, i. 490 , ii. 227 ; iii. 93. 733. nerve, ii. 284. filaments of nerves, iv. 547. vein, iv. 1404. //y/crt-oi bitar canal, ii. 208. or canine fossa, ii. 207, 208. groove, ii. 208. /rt/'rr7-spinal artery, iv. 435. Infra spinatus muscle, i. 217 ; iv. 436. /7///-<7-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 Cephalopod.v. Infusoria, theory of the first origin of, ii. 4:0. organs of circulation in, i. 654. digestive 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 luminous- ness, iii, 198. ingesta 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. 368. 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-cutaneous 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 tlie innominate artery, iii. 580, 581. Innominate bone, ii. 776 ; s. 114. its office, s. 114. border, superior, s. 114. anterior, s. 1 14. inferior, s. 1 14. posterior, s. 1 14. surface, external or femoral, s. 115. acetabulum, or cotyloid cavity, s. 116. descending ramus, or body, of the ischium, s. 1 16. horizontal ramus, or body, of the pubis, s. 116. ascendii g ramus of the ischium, s. 1 16. 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. 1 17. iliac tuberosity, s. 1 17. 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. Insnlivation of food, process of, s. 397, lunction 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 tlu system of Mr. Stephens, ii 850. Sub-class I. Mandibulata, ii. 859. Ord. I. Coleoptera, ii. 859. II. Dermaptera, ii. 861. III, Orthoptera, ii. 864. IV. Neuroptera ii. 864. V. Trichoptera, ii. 865. VI. Hymenoptera, ii. 863. VII. Strepsiptera, ii. 866. Sub-class II. llausteilata, ii, 866. Ord. Vlll. Lepidoptera, ii. 866. IX. Diptera, il. 867. X. Homaloptera, ii. 867. XI. Aphaniptera, ii. 867. XII. Aptera, ii. 863. XIII. Ilemiptera, ii. 868. XIV. Homoptera, ii. 868. different states of existence, ii. 869. the egg, ii. 8G9. 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 larv®, iii. 441. mode of progression of the pedate larv®, iii. 441. growth and changes of the larva, ii. 874; iii. J| 539. the pupa, nymph, aurelia, or chrysalis, ii. 879. the imago or perfect state, ii. 880. *5 circulatory system, i. 651 ; ii. 976. ^ the heart, or great dorsal vessel, ii, 976. generation, organs of, ii. 441. 990. "* ova of insects, s, [1 10.] spermatozoa of Insecta, iv. 488. mode of reproduction of, s. 33. GENERAL INDEX. 799 Insecta — coniinued. dermo-skeleton, ii. 881. its chemical composition, — chitine or ento- moline, ii. 881. its thirteen segments, ii. 882. abdomen, ii. 918. articulations, ii. 883. head, table of the parts and appendag’es of the, ii. 885. account of these, ii. 885. antenn®, ii. 890. development of the head, ii. S09, internal parts of the liead, ii. 892. mandibles, ii. 888. maxill«, 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. 926. file, ii. 928. neuration, or distribution of the trachea? in the wings, ii. 926. use of the wings of insects, iii. .5.39. powers of flight of insects, iii. 419. See Mo* TiON, Animal. powers of leaping of insects, iii. 475. velocity of predaceous insects, iii. 443. locomotive powers of aquatic insects, iii. 434. thorax, ii. 91 1. meso-thorax, ii. 914. meta-thorax, ii. 914. pro-thorax, ii. 914. table of parts, ii. 913. muscular system, ii. 934 j iii. 538. muscles of tl>e 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. nerves of the head, ii. 945. of the 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. 9(51. vision, ii. 960. optic nerves of the’ compound eyes of insects, iii. 775. nutrition, organs of, ii. 965. alimentary canal of larva, ti. 966; s. 298, appendages ofT:he canal, ii. 973. alimentary canal of perfect insect, ii. 905; s. 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. U42. 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. 982. function of respiration, ii. 987. See Respiration. Insecta^ — respiratory movements of insects, iv. 1019. tegumentary appendages, — hair, scales, spines, ii. 993. temperature of, ii. 650. hermaphroditism among, ii. 721. In.secta — 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. Erinacead®, or hedgehogs, ii. 994. Soricidse, or shrews, ii. 994. Talpidae, or moles, ii. 994. • Tupaiadee, or Tupaia family, ii. 994. Insectivora — 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 Insectivora during winter, ii. 764. lnses$ores, 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 Ilcil, 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, ct scq, I. Instincts designed for the preservation of tiie 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. II. 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. nid.fication, 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 creation 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 ol 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 w'ill 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. Ijitonpcrance, \or\g coniinued, a cause of wasting of the brain, iii. 720. delirium tremens, iii. 720. IntensUp of the human voice, iv. 1475. Interar'ticular 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-humeral branches of, i. 360. great, of the older anatomists, s. 423, See Sym- pathetic Nerve. second, i. 217. third, i. 217. 3 F 4 sno GENERAL INDEX. Iiitcrcoslal — continued, veins, i. 3G5 ; iv. 1400. left superior, iv. 1400. Intcr-costo-hu77U'ral nerve, iv. 7fi0. Intcrcrural or interpeduncular space, iii. G73. luicr-l'nniiiar fibro-cartilaKinous tissue, s. 1‘25. Interlobular iii. 171. ducts, iii. 169. fissure of liver, iii. 160. spaces of liver, iii. 166. veins, iii. 166, 167. 171 ; iv. I4M. Iniermaxillary\ie>\\Q^ ii. 210. InlermUtcnt fever, characters of the urine in, iv. 1292. Iniermu'icidar ligaments, i. 217. external, i. 2i7. internal, i. 217. Interosseal artery, posteri r, ii. 364 ; iv. 225. ^eins, palmar, iv. 1107. Intcrossei externi digitorum manus muscles, ii, 251, relations and uses, ii .522. interni digitorum manus muscles, il. 521. relations and uses, ii. .522. pedis dorsales rel externi muscles, ii. 358. pedis plantares muscles, ii. 358. //iA7*t>ssut 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 condyles, iii. 67. oblique fracture of the lower end of the femur, iii. 67. into the knee-joint, iii. 68. by detachment of the outer condyle, iii. 68. bv detachment of the inner condyle, iii. 68. Tl fracture, iii. 6S, 802 GENERAL INDEX. Knee-Joint, abnormal conditions — continued, fractures of the tibia near the knee, iii. 69. oblique into the joint, iii. 09. transverse, iii. G;i. fracture of the patella, iii, G9. dislocations, iii. 71. of the femur from the tibia at the knee- joint, iii. 71. signs of the accident, iii. 71 . of the femur backwards, iii, 71 . forwards, iii. 72. lateral luxations of tlie 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. 71. 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 tl>e quadriceps extensor tendon from its attachment to the superior border of the patella, iii. 77. rupture of the llgamcntum patellte, iii. 78. Knee-pan^ ii. 168. See Patella. L. l.abia. See Lips. Labia pudendi, or majora, s. 708. minora, v, interna, s, 710. abnormal anatomy of the labia, s. 714. development oflabia 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 leporinnm duplex cum palato fisso, iv. 953. sternal labium of Arachnida, i. 203, Labimr proce.ss. See Parturition. LabrideVy a family of Fishes, iii. 957. Labyrinth, membraneous, ii. 533. 63G, 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, 55S. 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. Lahyrinthodun, teeth of, iv. 867, 868. Lacerated foramen, anterior, i. 734. posticum in hasi cranii, i. 732, 733. orbital fissure, inferior, i. 72H. superior, i. 728. orbital foramen, anterior, i. 728. superior, i. 728. iMcerta viridis (Lizard), nervous system of the, iii. 620. organs and mode of progression of the, iii. 449. Sec also Lizards. Lacertidee, a family of Reptilia, iv. 26.5, et seq. Lace-winged flies (Hemerobida?), 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, e.xcept the orbit and muscles), iii. 78. 1. Eyelids, iii. 78. general description, iii. 78. rima palpebrarum, iii. 79. movements of the eyelids, iii. 79. winking, iii. 79. Lachrymal Orcan.s, — continued. Meioomian follicles, iii. 79. adaptation of the eyelids, iii. 79. cantlii, iii. 79. secondary fissure of inner canthus, iii. 79. lachrymal papilla and puncture, iii. 80. lacus lachrymalis, iii. SO. lachrymal caruncle, iii. 80. plica semilunaris, 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 palpehra 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. hordeolum, 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 inferior 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. meinbrana 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 conjunctival secretion, iii. 85. intimate structure of the palpebral conjunctiva, iii. 85. chorion, iii. 85. papillary body, iii, 85. epithelium of palpebral conjunctiva, iii. RG. intimate structure of sclerotic conjunctiva, iii. 86. papillce ( ?), 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. 99. 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. lachrymal muscle (tensor tarsi), iii. 02. origin, iii. 92. relations, iii. 92. actions, iii, 93. nerves, iii. 93. from first division of the fifrli, 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. 03, 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 Lachrymal — continued. Comparative anatomy and development, iii. 94, 1. Eyelids, 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. flocculeiit 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, iii. 98. 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. 99. eyelids, iii. 99. tarsal cartilages, iii. 99. lachrymal gland, iii. 99. inner canthus, iii. 99. lachrymal caruncle, iii. 99. Lachrymal calculi, or dacryoliths, iv. 82. process, ii. 213. tubercle, ii. 208 ; iii. 783. Lachrymaria, or lachrymatory animalcule, iv. 13. Lachrymo-nasal canal, ii. 208. Lacmg, tight, injurious effects of, on the liver, iii. 188. Lacmhe^ timbri®, or morsus diaboli, of Fallopian tube, s. 602. Lacinularia, a genus of Rotifera, iv. 403. formation of ephippial ovum in, s [119], [127.] Lacrymce, or tears, iii. 90. chemical composition, iii. 90. Lactation, usually a preventive to conception, ii, 457. cessaLion of menstruation during, i. 440. a predisposing cause of fragility of the bones, L 411. Lactcais, 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. 800 ; iv. 1271, constitution and chemical properties of, iii. 800 : iv. 1271. a normal element of the blood, iv. 460. Lncuncc of urethra, iv. 1250. lacuna magna, iv. 1250. diseased Conditions of the, iv. 1262. of bones, iii. 850. See Osseou.s System. Lacus lachrymalis, iii. 80. Lady-cow (Coccinella), ii. 863. Lag07ny^, or rat hare, anatomy of the, iv. .374, et seq. Lagephthabnos, or morbid retraction of the upper eyelid, iii. 79. Lagoihrix, a genus of Quadrumana, iv. 210, et seq. See Quaurumana. characters of the genus, iv. 210. Laguncula repens, a species of Polypifera, iv. 56. mode of reproduction of, iv. 56, 57. Lamhdoidal suture, i. 737. Lamellibranchmta, digestive organs of the, s. 299. renal organs of, iv. 232. Lamellicornes , 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. 6brous, of valves of veins, iv. 1379. gyrorum, or tube of cochlea ii. 532. median fibrous, iv. 1134 Lamina — contimied, recto-vesical, of the pelvic fascia, iii. 933. spiralis, ii. 532. LamincB of bones, iii. 849. See Osseous Tissue. of cerebellum, iii. 689, et seq. intestinales, s. 401. membranous, of the bladder in man, i. 3S0. of sacrum, s. 118. of vertebra, i. 250. Laminated ligaments, ii. 264. Lamisca, a genus of Myriapoda, iii. 546, et seq Lamna, teeth of, iv. 8G6. 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. 9G3. LajnpyridcB, or glow-worms, ii. 862. characters, ii. 862. lumiiiousness of. See Luminousness, Animal. Lancelet (Amphioxus lauceolatus), 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. 1346. the amalgamate type, as the classical languages, iv. 1346. the anaptotic type, as English, iv. 1346. principal groups under which the various languages may be studied, iv. 1347. affinities between the Australian and Tamulian of Southern India, iv, 1363. cranium, iv. 1322. Lard, chemical characters of, ii. 232, lAirits cyauorhynchus (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 larvte 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. 8S6, 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 !3. phenomena observed when the recurrent nerves are diseased, compressed, or cut, iii. 113. spasmodic closure of the rima glottidis, iii. 113. laryngismus stridulus, iii. 113. 124. effects of the lesion of the laryngeal nerves in en- feebling tlie voice, iii. 895. crowing sound after section of the inferior laryngeal nerves, iii. 894. Lat-yngismus 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. 118. diphtherite, iii. 117. erysipelas, iii. 118. oedema of the submucous tissue, iii. 116. varieties, iii. 1 17. idiopathic, iii. 117. traumatic, iii. 1 17. oedema without evidence of inflammation, iii. 117. causes of death, iii. 117. spasm of the glottis, iii. 117. scarlatina anginosa, or angina maligna, iii. 117. symptoms and appearance, iii. 117. sloughing, iii. 1 18. symptoms, iii. 1 17. thickening by gradual deposit, iii. 117. ulceration, in. 1 19. 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. 1 19. .symptoms, iii. 120. Laryngotomy, operation for, iii. 573. Larynx (in general anatomy), iii. 100, general description, iii. 100. Sihl GENERAL INDEX, Larvnx — continiicd. 1 . cartilages, Hi. 100. cricoid, iii. 101. thyroid, iii. 101. arytenoid, iii. 102. corniciila laryngis, iii. 102. cuneiform cartilages, Hi. 103. einglottis, iii. 103. 2. articulations and ligaments, iii. 103. extrinsic articulations, iii. 103. hyo-thyroid articulation, iii. 103. ligainentum thyro hyoideum medium, iii. 104. ligamenta hyo tliyroidea lateralia, iii. 101. ligaments of the epiglottis, iii. )()1. ligamentuin thyro-epiglottideum, iii. 104. ligamentum byo epiglottideum, iii. 104. ligainentum glosso-cpigloUideum, iii. 104. tracheo-cric >itlcan articulation, iii. 104. intrinsic articulations, iii. 104. J. crico-thyroid articulation, iii. 104. crico-thyroid ligament, iii. 101. lateral crico-thyroid ligament, iii. 104. 2. crico-arytenoid articulation, iii. 105. tliyro-arytenoid ligaments or chordte vo- cales, iii. 105. inferior, iii. 105. superior, iii. 105. 3. muscles, iii. 105. extrinsic, iii. 10.5. See Neck, Muscles of the. intrinsic, iii. 105. aryteno-epiglottMei, iii. 1 10. action, iii. 1 10. arytenoidei, iii. 107. obliquus, iii. 107. transversns, iii. 107. crico-arytenoidei laterales, iii. 107. postici, iii. 100. crico.thyroidei, iii. 105. action, iii. 100. thyro-arytenoidei, iii. 108. action, iii. 100. thyro-epiglottidei, iii. 110. recapitulation of the action of the intrinsic muscles of the larynx, iii. 1 10. 4. blood-vessels, iii. 110. 5. structures called glands, iii. 110. arytenoid gland, iii. 110. epiglottic gland, iii. 111. 0. mucous membrane, iii. 111. glosso-epiglottic folds, iii. 111. aryteno-epiglottic folds, iii. III. rima gloitidis, iii. 111. ponuim Adnmi, iii. 112. ventricles of the larynx, iii. 112. 7. nerves, iii. 112. superior laryngeal, iii. 112. inferior or recurrent laryngeal, iii. 113. functions of the laryngeal nerves, iii. 1 1.3. motions of the glottis during respiration, iii. 113. phenomena observed when the recurrent nerves arc diseased, compressed, or cut, iii. 113. spasmodic closure of the rima glottklis, iii. 1 13. laryngismus stridulus, iii. 113. description of the larynx deprived of its extrinsic muscles, iii. 1 14. anterior aspect, iii. 114. lateral, iii. 1 14. posterior, iii. 114. inferior, iii. 114. internal, iii. 114. vocal functions of the larynx. See Voice. the larynx in infancy, i. 70. in old age, i. 79. Larynx, morbid anatomy and pathology of the, iii. 114. general remarks on the recency of accurate knowledge of the abnormal conditions of the larynx, in. 1 14. general remarks on diseased conditions of the laryn- geal mucous membrane, iii. 115, ot the cartilages, iii. 115. ligaments, iii. 115. muscles, iii. 115. submucous tissue, iii. 1 15. 1. acute inflammation of the mucous membrane, iii. 115 of the child, or croup, iii. 115. age at which it occurs, iii. 1 15. condition of the lungs and brain in fatal cases of, iii. 116. false or adventitious membrane of croup, iii. 116. origin of the disease, iii. 1 15. stages of, described, iii. 1 1.5. first stage, iii. 1 15. second stage, iii. 1 15. third or fatal stage, iii. ! 16. of the adult, iii. 116. causes, iii. 116. cedema of the submucous tissue, iii. 116. varieties, iii. 117. Larynx, o?dema of submucous tissue — coiilhined. symptoms, iii. il7. thickening, iii. 117. ulceration, iii. 1 19. symptoms, iii. 120. varieties, iii. 119, See also Laryngitis. gangrene of the softer tissue.s of the larynx, iii 120. 2. diseased condition of llie cartilages of the larynx iii. 120. phthisis luryngea, iii. 120. causes of, and localities attacked, iii, 120. progress of the aisease, iii. 121. post mortem appearances, iii. 120, 121. symptoms, iii. I2l. treatment for cure of, iii. 121. alteration in size and shape of the epiglottis (by. pertrophy and atrophy), iii, 122. leaf-like expansion, iii. 122. 3. derangements of the function of the larynx un. attended with organic change, iii. 122. exceptions to the use of the epiglottis, iii. 122. epiglottis, inert, iii, 123. condition of the epiglottis in an animal asphyx. iated by carbonic acid, iii. 123. 4. pathological conditions of the muscles of the larynx, iii. 123. 5. diseased conditions of the laryngeal ligaments, iii, 126. Laserpilium, iv. 862. Lateral fasciculi, ii. 269. ligaments, i. 251. of wrist-joint, external, iv. 1507. internal, iv. 1507. of metacarpo-phalangeal joints, ii. 510. internal, i. 152. process, i. 732. sinus, i. 732. sulcus, i. 736. Latissimus colli muscle of Albinus, iii. 5G6. dorsi muscle, i. 5. 217. 362 3'.8 ; iv. 435. 576j s. 137. Laxaior tympaui muscle, i, 728. Lcad^ method of determining the presence of, in organic substances, iii. 804. Leaping, injuries of the tendons of the leg, arising from, iii. 132. Leaping powers of various animals, iii. 474. of the cat, iii. 474. cricket, iii. 474. grasshopper, iii. 474. leopard, ii). 474. tiger, iii. 474. in insects, iii. 475. in quadrupeds, iii. 475. in man, iii. 478. estimate of the expenditure of muscular action in leaping, iii. 478. increase of the respiration and circulation in leaping, iii. 479. Leather, art of making, ii. 404. Leaves of ))lants, sleep of, iv. 678. Leeches (Hirudines), organs and mode of progression of the, iii. 441. organs of circulation in the, i. 651. eyes of, i. 167. vascular system of, i. 170. organs of generation, i. 171. muscles of the, iii. 538. T.ceuwenhoeh's discovery of the Rotifera, iv. 397. “ Leg, Rarbadoes,” iv. 1011. Leg-bones, ii. 168. See Fibula ; Tibia. Leg, regions of tlie, iii. 126. general survey, iii. 127. external form of the leg, iii. 127. integument, iii. 127 causes of slowness of the healing process on the front and outer part of the leg, iii. 127. inflammation and abscess of the cellular tissue, iii. 128. varicose condition of the capillaries of the integn- ment, iii. 128 ; iv. 1398. superficial fascia, iii. 128. superficial veins, iii. 128. major saphena, iii, 128. minor saphena, iii. 128. varicose ulcer, its treatment, iii. 1.30. superficial nerves, iii. 130. internal saphenus, iii. 130. external sajihenus or communicans tibialis, iii. 130. superficial lymphatics, Hi, 130. aponeurosis, iii. 130. of the anterior region, iii. 130. of the posierior region, iii. 130. superficial layer, iii. 130. deep layer, iii. 130. anterior region of the leg, iii. 131. muscles, iii. 131 . anterior tibial artery, recurrent tibial, iii. 131. operations for ligaturing, varieties^ iii. 132. relations, iii. 132. GENERAL INDEX. 805 Leg — continued. posterior region of the leg, iii. 132. muscles, iii. 132. superticial layer, iii. 132. gastrocnemius and soleus, iU. 132. division of tlie teudo Achillis, iii. 132. plantaris, iii. 133. deep layer, iii. 133. arteries, iii. 133. posterior tibial, iii. 133. course, iii. 133. relations, iii. 133. operation for ligaturing, iii. 133. peroneal, iii. 134. course, iii. 134. relations, iii. 134. operations for ligaturing, iii. 134. venae comites, iii, 134. nerve, iii. 134. deep lymphatics, iii. 1.34. difficulty of preserving the proper position of the fibula in fracture, iii. 134. precaution witli respect to the projecting angle which the tibia, when amputated, presents anteriorly, iii. 135. 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*». liability of the tibia to disease, iii. 136. curve of the tibia iii. 136. fracture of the leg, iii. 136. of the fibula alone, iii, 136. Leg, muscles of the, iii. 137. anterior group, iii. 137, 1. tibialis anticus, iii, 137. 2. extensor longus digilorum, 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 brevis, iii. 13f^. combined action, iii. 133. posterior group, iii. 138. superficial layer, iii. 138. 1. gastrocnemius, iii. 138. relations, iii. 138. 2. soleus, iii. 138. relations, iii. 138. tendo Achillis, iii. 139. action, lii. 139. 3. plantaris, iii. 139. action, iii. 139. . deep layer, iii. 139. 1. popliteus, iii. 139. 2. flexor longus digitoruni. iii. 130. accessory muscles, iii. 139. 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. 41 1. 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. J^eguminous seeds, properties of, as food, ii. 13; s. 394, constituents of, s. 394. i.emmmg., economy and mode of proceeding of, iii. 17. Lcwon-juice, considered as an article of food, s. 395. Lc7nu)\ a genus of Quadrumann, iv. 215, et seq. See Qua- DHUMANA. characters of the genus, iv. 215. organs and mode of locomotion of the, iii. 456. flying (Galeopithecus), teeth of the, iv. 870. tardigradus, iii. 456. a family of Quadrumana, iv. 214. et scq. characters of the family, iv. 214. genera and species of, iv. 214, 215. Lews, crystalline, of the eye, ii. 194, See also Crystalline lens ; Eye. form of the lens, iv. 1440. retractive index of the surface of the lens, iv. 1440. Lenses, influence of convex and concave, on the rays of light passing through them, iii. 331, convex lens described, iii. 337. Dr. Brewster’s lens of diamond, sapphire, or carbuncle, iii. ,337. Dr, Wollaston’s doublet, iii. 338. Coddington lens, iii. 339. Lenses — continued. Stanhope lens, iii. 339. achromatic lenses, how obtained, iv. 1438. Lenticnlar bone, ii. 547- or ciliary ganglion, ii. 281 ; iii. 785 ; iv. 622. glands of the stomach, s. 324. nerve, ii. 281 ; iii. 785. process of incus, ii. 547. Leopard, organs of voice of the, iv, 1490. powers of leaping of the, iii. 474. urine of the, iv. 1279. l.epadella, a genus of Holifera, iv. 406. Lepadicea, a genus of Cirrhopoda, i. 6^4. See Ciruhopoda. J.epas, nervous filaments of the, iii. 607. l.cpidoptcra, an order of Insecta, ii. 866. characters of the order, ii. 866. divisions into sections, ii. 866, 867. mode of flight of the, iii. 421. mode of flight of the nocturnal Lepidoptera, iii. 422. nervous system of the, iii. 61 1. ovum of Lepidoptera, s. [111.] [113.] Lepidosiren, iii. 990. respiratory and circulatory apparatus in the, iii. 990. muscles of the, iii. .543. Leptoclinum, a genus of Tunicata iv. 1 191, ct seq. characters of the genus iv. 1191. Leptopus longipes, organs and mode of progression of the, iii. 445. Lepus, or hare, anatomy of the, iv. 369, ct seq. Lepus cuniculus (rabbit), nervous system of the, iii. 623. organs of voice of the, iv. 1491 . Lesueura vitrea, nervous system of, iii. 602. Lethargy. See Hibernation. Leucitthiopes, Lcuca^thiupia, and Leucopathia. See Al- bino. Lcucin, iv. 164. Leucoma of the cornea, ii. 177 Leucorrhea, s. 694. 707. Lcucophrys, or ciliated animalcule, iv. 13. Levator alae nasi proprius muscle, iii. 729. anguli oris muscle, ii. 224. relations and action, ii. 224, 225 anguli scapulae muscle, i, 370 ; iv. 576. anl muscle, i. 178 ; iii, 944'; iv. 1246 ; s. 138. 369. action, i. 179. origin, i. ]178. labii superioris alteque nasi muscle, ii. 222. 224 . iii. 728. relations and action, ii. 222, 224 ; iii. 728 menti muscle, ii. 225. relations and action, ii. 225. palati muscle, i. 734 ; iii. .951, 952. relations and action, iii. 952. palpebrse superioris muscle, iii. 79 82. 784. action of the levator, iii. 788. Levatores breviores costarum muscles, iv. 334. 1055. longiores costarum. iv. 1055. prostatae muscle, iv. 147. 1246 uriuae muscles, i. 178. Jxver, theory of the, in animal dynamics, iii. 410. See Mo I ION, Animal. Libellulina, or dragon flies, ii. 864. characters of the section, ii. 864. wings and mode of flight of the, iii. 423. Lichanotus, a genus of Quadrumana, iv. 215, c/ scq. See Quadrumana. characters of the genus, iv. 215. Lichens, reproductive system of, s. *228. formation and development of the germ, s. 228. the thallus, s. 229. the hypothallus, s. 229. the receptacles within or upon which the spores or spore-like organs are produced, s. 229. varieties, apothecia, s. 229. spermogonise, s. 229. pycnides, s. 229, 230. lamina proligera, s. 229. paraphyses, s. 230. thecae, s. 230. antheridia of lichens, s. 230. function of, s. 230. pycnides of lichens, s. 230. summary of reproductive organs of lichens, s. 231. Lien. 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. 1469. 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. 36. associated with a high degree of irritability of the muscular fibre, iii. 36. Life, iii. 14!. I. General views, iii. 141. definition, iii. 141. tendency of the changes exhibited by a livin® being, iii. 141. method of prosecuting the inquiry, iii. 1 11. 80(j GENERAL INDEX, Life — continued- diflicuUy in the attainment of genera) laws in some departments of science, iii. 141. difficulties which beset the investigation of the laws of vital action, iii. M2, conditions required for the production of vital actions, — organised structure and stimulus, iii. M2. vital properties due to the act of organisation, iii. U2. II. History of opinions, iii. M3. abstract terms used in the earlier ages of the world expressing a vague idea of a property inherent in a body that exhibiis it, iii. M3, the term life as applied by the older philosophers, iii. 143. tendencies in the unenlightened mind from whicli the foregoing modes of explaining vital pheno- mena have resulted, iii. 144. modification which the forcmentioned doctrines have undergone, iii. 144. distinctness of life and mind, iii. M4. doctrine of the vital principle put forth by Barthez, vis medicatrix naturie of Hofl'man and Cullen, nisus formativus of Blumenbach, organic agent of Dr. I'rout, and organic force of Muller, iii. M.*). Hunter’s doctrine of the vital principle, iii. 145. precise import attached to the term, iii. 146. Dr. Front’s definition, iii. 146. III. Nature and causes of vital action, iii. 146. all clianges 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. 1 18. 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 ihose forms of it capable of be- coming organised, iii. 148. total change effr'Cted 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 Irom 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 d'le to tire 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 pi-evious existence of life, considered, iii. 15b. many actions perfoi-med by living beings common to tiiem 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 Iiave 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 cliemists to produce organic com* pounds probably due to their want of ac- quaintance witli 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 — conthuicd. VI. Vitality in a dormant 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. agent.s 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. 1.57. hibernation of plant.s, iii. 157. hibernation of aiiimals, iii. 157. animals enclosed in rocks and trees, iii. 158. syncope, iii. 159. suspension of vital action in parts of the human body, iii. 1.59. atomic theory of Dr. Daubeny, iii. 159. Ligament^ accessory, of capsular, ii. 779. alar, iv, 521. annular or orbicular, iv. 2l!9. of carpus, dorsal, ii. 505. articular, i. 250. capsular, i. 250. definition, i. 250. elastic, i. 251. funicular, i. 251. uses, i. 250. astragalo-scapboid, ii. 343. auriculaj anterius, ii. 551. posterius, ii. 551 . broad, of uterus, s. 705. calcaneo-scaphoid, external, ii. 343. inferior, ii. 343. capsular (capsula fibrosa ossis femoris). ii. 778 : iv. 874. coronary, of tlie liver, iii. 940. chondro- or costo-xiphoid, iv. 1033. coraco-humeral, or accessory, iv. 574, .575. costo-transverse, anterior or long, iv. 1032. posterior, iv. 1032. cotyloid (ligameiiuim cotyloideum, fibro-cartilagi- neum, labium cartilagineum acetabuli' ii. 777. crico-thyroid, iii. 104. lateral, iii. 105. dorsal, of tarsus, ii. 343. falciform, iii, 160. of the liver, 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. 1 124. hyo-epiglottideum, iii. 101. iliac, posterior lateral, or lateral sacro iliac of Soem- mering, s. 124. ilio-lumbar, s. 124. interosseus, iii. 131 ; iv. 1506. of tarsus, ii. 34.3. astragalo-calcaneal. ii. 343. lateral, of wrist-joint, external, iv. 1.507. internal, iv. 1507. lumbo-.sacral, or sacro-vertebral, s. 121. mucous, of knee, iii, 46. of the notch, iv. 434. odontoid, i. 732, phrenico-gastticum of Soemmering, iii. 941. phrenico-lineale seu suspensorium, iv. 771. plantar, of tarsus, ii. 343. Poupan’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. 1.506. round (ligamentum teres capitis femoris, seu liga- mentum 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, s. 124. sacro-sciatic, great, s. 124. 207. lesser, s. 124. 207. sacro-vertebral, or lumbo-sacral, s. 121. stellate, iv, 1032. GENERAL INDEX. 807 J.igament^ continued. stylo-maxillary ligament, ii. 2U ; iv. 93v^. sub-pubic, or ligamemum arcuatum, s. 126. 207. suspensory, iii. 926; s. 709. of liver, iii. 160, thyro-epiglottideum, iii. 10-1. tliyro-hyoideum medium, iii. lOJ. transverse ff acetabulum, ii. 777. triangular, iii. 930. of urethra, iv. 1247. Ligamenta inter-vertebralia, iv. 1022. pubo-prostatlca media, iv. 147. lateralia, iv. 147. radiatim disjecta, iv. 1032. subrtava, ii. 263 ; s. 12!. subflava of the vertebrae, i. 251. suspensoria of mammary glands, iii. 248. Ligaments in general ; — essential properties and offices of, ii. 264. office of the ligaments with respect to locomotion, iii. 41-5. predominating forms, ii. 264. 1. ca]>sular, ii. 264. ' 2. I^unicular, ii. 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 thumb, 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, li. 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- byo-rhyroidea lateralia, iii. 104. interosseous, of carpal bones, ii. 508. inter-spinous, s. 121. of jaw-b(*ne. 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. r>10. palmar annular, of carpus, ii. 508. carpo-metacarpal. ii. .509. palpebral, external, iii. 81. internal, iii. 81. of pelvis, s, 121 . phalangeal, oflingers, 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. supra-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 voca(es), 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, s. 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. 263. Ligamentum arcuatum, or sub-pubic ligament, s. 126. externum, ii. 3. internum, ii. 3. hicorne, i. 360 ; iv. 1407. deutatum, or serrated membrane of Gordon, iii. 645. office of ihe ligament, iii, 616. Ligamentum — continued. diiodeni renale, s. 341. hepatico-duodenale, s. 341. latum pulmonis, iv. 2. nuchjB, i 732. of Pachydermata, iii, 876. patell(£, 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. 335. correction, iii. 335. spherical, iii. 334. correction, iii. 3.34. 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. 136. 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. IJghts. See Lungs. Lightning, action of, on the vital power of the heart i. 723. syncope by. i. 797. Limax ater (common black slugl, nervous system of the, iii. 606. inaximus, tongue of, iv, 1142. 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. imc'? alba, i. 3*, 4"^. 9, 10,18. cervicalis, ii. 230. aspera, iii. 44. ilio pectineal, or Hnea innominata, s. 117. 127. ilio-pectinea muscle, i. 5. semilunaris, i. 6. temporalis, i. 729. 735. Linear transverse, i. 9. of sacrum, s. 1 18. Lingua. See Tongue. Lingual artery, i. 485 ; iv. 1141. branches, iv. 1 141, glands, anterior, iv. 426. posterior, iv. 426. muscles, iii. 544. 565; iv. 553. transverse, iv. 1126. vertical, iv. 1 126. lateral, iv. 1126. inferior, iv. 1 126. longitudinal, iv. 1126. nerve, li. 292. 295 ; iii. 949 ; iv. 820. 1 141. branch of the fifth nerve, iv. 858. 1141. branches of glosso-pharyiigeal nerve, ii. 497. quinsy, iv. 1154. veins, iv. 1406. Linguntula, a 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. 9.54. Liquamcn, 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. !50. puris in which pus floats, iii. 754. seminis, iv. 472, 473. Lilhates, deposit of, in urine in disease, iv. 1282. Lithic acid, iv. 1270. constitution and chemical properties of, iv. 1270. de]>osits of, in urine in disease, iv. 1282. Lithobius, a genus of Myriapoda, iii. 547, et seq. 560, et seq» Lithotomy, operation of, iii. 923, 931. 933. surgical considerations in, i. 174. bilateral and lateral methods, iii. 932. 934. supra-j ubic. operation of, i 9. situation, iii. 160. 608 GENERAL INDEX. Liver, Normal Anatomv of the, ii. 1^3, -181 ; iii. IGO. form, iii. IGO. position, iii. 160 relations, iii. 160. ligaments, iii. 160. coronary ligament of the, iii. 010. falciform ligament of the, iii. 036. OH. base and apex of the ligament, iii. 936. surfaces of the falx, iii. 036. triangular ligaments of the, iii. 010. lobulus caudatus, iii. 037. fissures, iii. 161. lobes, iii. 162. coverings, iii. 162. peritoneum of the, iii. 01.3, b.isement membrane of the, iii. -187. internal compo.ition of the liver, iii. *107 colour, iii. 162. texture, iii. 163. dimension^, iii. 163. chemical analysis of human liver, iii. 163. of bullock's liver, iii. 163. varieties in form, iii. 163. of po.sition, iii. 163. gall-bladder, iii. 164. relations, iii. 164. coats, iii. 164. excretory ducts of gall-b'adder ami liver, iii. 161. coats, iii. 164. v.arieties in the gall-bladder, iii. 164. structure of the live**, iii. 164. the terms lobule and acinus as used by Malpighi, Muller, and Kiernan, iii. 165. Glisson’.s capsule, iii. 166. vaginal portion, iii. 107. interlobular portion, iii. 167. lobular portion, iii. 167. portal vein. iii. 167, vaginal branches and vaginal plexus, iii. 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 ducts, iii. 170. vascularity of the biliary ducts, iii. 170. mucous membrane and follicles of the biliary ducts, iii. 171. hepatic artery, iii, 17!. vaginal arteries, iii. 171. interlobular arteries, iii. 171. lobular arteries, iii. 171. distribution, iii. 171. hepatic veins, iii. 172. interlobular veins, iii. 173 suhlobular 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 ot portal and caval veins, iii. 176. hepatic veins of diving animals, iii. 176. development of the liver in the embryo, li'. 177. in the fowl, iii. 177. in the human subject, iii. 177. uses of the liver, iii. 178. 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 Ferrein, iii. 181. researches of M. Dujardin, iii. 182. the liver in infancy, i. 68. liver in various animals, iv, 415. See under the various headings. (Dbtomahepnticunn), ii. 121. Liver, Pathological Anatomy of the, iii. 182 1. diseases of the serous membrane, iii. 182. acute inflammation, or membranous hepatitis, iii. 182. chronic inflammation, iii. 183. depositions in the subserous tissue, iii 183. 2. diseases of the mucous membrane, iii. 183. <7. thickening, iii. IH3. b. softening, iii. 183. c. ha?morrliage, iii. 183. (t. pu«, iii. 183. €* abnormal deposits, iii. 183. I..IVER — conihmed. 3. disorders of the venous circulation, iii. 183. n. general congestion, iii. I84. b. hei>atic venous congestion, iii. 181. c, portal venou.s 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. eflectsof 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. induration, iii. 190. /. fatty degeneration, iii. (90. unhealthy formation of fatty matter in the liver, iv. 94. causes, iv. 95. g. abscess, iii. 190. h. tubercle, iii. 192. i. scirrhus, iii. 192. scirrhous tubercle, iii. 102. tubera diflusa of Farre, iii. 193. characters of, iii. 193. k. medullary sarcoma, iii. 193. seal of origin of carcinoma, iii. 104. /. fungus haematocles, iii. 194. m. melanosis, iii. 194. C. disorders of function, iii. 104. 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. 106. 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, ct scq. 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. 1 117. Lobes of organs. See those organs, of cereheliiim. See Cerebellum. of the lungs, s. 258, See Lungs; Respiration, Or- gans OF. Loh}\ or head-cowls, of Pteropoda, iv. 174. Lohophyllia angulosa, a genus of Polypifera, iv. 19. Lobster, the, i. 704. See Crustacea. mode of progression of the, iii. 436. nervous system of the, iii. 613. Lobular 2iriQ\\e.s,, 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 car, ii. 551 . of kidney, iv. 233, 234. of the liver, iii. 165, 166 ; s. 369. of the lungs, s. 264. minute anatomy of the lobules, s, 266. Lobulus caudatus, iii. 161, 162. 937. quadrafus, iii. 162 ; s. 309. Spigelii, iii. 161, 162; s. 309. Locomotion, function of, in animals generally, i. M5. See Motion, Animal. manner in which the posterior columns of the spinal cord may contribute to the exercise of the locomotive functions, iii. 721 Q. locomotion of animalcules, iv.5. See Polygastrta. and in Crustacea, i. 761. system of Pteropoda, iv. 173. of insects, ii. 924. See Insecta. in the larva of insects, ii. 873. Locus niger of the crus cerebri, iii. 647 ; 722 M. porforatus anticus of base of brain, iii. 672. Locusts (Locustidm), ii 864. association of, in. 16, 17. their economy and mode of proceeding, iii. 17 ova of the Loligo, s. [lOG.] guttati, i. 114. London, sanitary condition of the population of, tested by the mean age at death, iv. 1471, 1472. Longicorncs, a tribe of Insects of the order Coleoptera, ii. 862. characters of the tribe, ii. 862- Longissimus dorsi muscle, i. 10. 372 ; s. 137 Longitudinal commissures of the brain, iii. 701. superior, iii. 701. GENERAL INDEX. 809 Lo)}gitudinal 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. 735. tracts of corpus callosum, iii. G74. Longu$ colli muscle, iii. 661. ],ophiodon, anatomy of the. See PachydjiRMata. Lophim piscatorius, nervous system of the, iii. 615. teeth of the. iii. 978. nostrils of, iii. 998. Lophobranchii, an order of Fishes, iii. 957. characters of the order, iii. 957. Lophopus Bakeri, formation and structure of the ova of, s. [127.] crystallinus, winter ovum and embryo of, s. [128. J 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. 42.5. nerves, anterior branches of, iv. 761. posterior branches of, iv. 752. plexus of nerves, iv. 764. veins, iv. 1413. Zww5o-abdorainal muscle, i. 7. plexus of nerves, iv. 761. XwwAo-ili-abdominal muscle, i. 7, Xww5o-pelvic articulations, s, 121. movements of tliis joint, s. 121. iwm^o-sacral ligament, s. 121. nerve, iv. 761. Lumbricales manOs muscles, ii. 521. relations and uses, ii. 521. pedis muscles, ii. 3.58. agricola, ovum of, s. [1 17 ] terrestris (common earth-worm), nervous system of the, iii. 607. organs of circulation in the, i. 650. organs and mode of progression of the, iii. 441. Lucanus cervus, or stag-beetle, ii. 861, note. Luminousness, Animal, iii. 197. I. enumeration of animals possessing the property of emitting light, iii. 197. II. characters and properties of animal light, iii. 198. colour in various animals, iii. 198. intensity, iii. 198, 199. smell, iii. 199. evolution of beat in connexion with animal lu- minousness, iii. 199. III. circumstances in which light is given out, and by which its intensity is aifected, iii. 199. 1. natural circumstances, iii. 199. a. influence of temperature, iii. 109. b, solar light, iii. 199. c. lunar light, iii. 199. d, abrupt collision with other bodies, iii. 199. e» loud noises, iii. 2u0, /. internal movements 'of the animals them- selves,— will, &c., iii. 20U. 2. artificial circumstances, iii. 200. a. accumulated electricity and electrical cur- rents, iii. 200. h. immersion in various fluid and gaseous media, iii. 2C0. c. pressure of their bodies, iii. 201. d. removal of the luminous organs, and re- moval of these and other organs, iii. 201. e. exposure to various degrees of lieat and moisture, iii. 201 . /. immersion in vacuo, iii. 201. g. removal from all foreign sources of light, iii. 201. IV. seat of luminousness in different animals, i. 45 ; iii. 201. V, anatomy of light-giving organs, iii. 202. VI. geographical distribution of luminous animals, iii. 203. VII. theories of animal luminou'ness, iii. 203. VIII. uses of animal luminousness, iii. 204. IX. luminousness of animals not innate, and other allied phenomena, iii. 204. luminousness of the human body, and emission of light from the eyes of vertebmte animals, iii. 204, luminousness of dead fishes and other dead animals, iii. 205. I.unar light, influence of, on animal luminousness, iii. 1D9. Lunar, or semilunar, bone of carpus, ii. 505. articulations, ii. 505. Lungs, in infancy, i. 67. air-cells, pulmonary, basement membrane of the iii. 487. a-symmetry of the, iv. 846. lymphatics of the, iii. 229, 230, pulmonary branches of nervus vagus, iii. 896. 902. pleura, iv. 1. mediastinum, iv. 1. ligamentum latum pulmonis, iv. 2. pleura pulmonalis, iv. 2. costalis, iv. 2. diaphragmatica, iv. 2. Supp. Lungs — continued. elastic power of the, iv. 1058. muscular contractility of the lungs, iv. 1060. of the volumes of air expelled from the lungs, iv. 1066. See also Respika tion, Ghgans of ; Thorax. Lungs, morbid anatomy of the, s. 292, atrophy of, in aged persons, i. 78, note. collapse of the lungs, s, 292. bronchitic, s. 292. associated with emphysema of the unaffected portions of the same lung, s. 292. asthmatic affections, s. 293. condition of the, in fatal cases of croup, iii. 116. excretions from the lungs (watery vapour and carbonic acid), ii. 149. fatty accumulation in the lungs, iv. 96. formation of concretions in the parenchima of the lungs, iv. 90. forms of disease recognised by English pathologists, s. 293. pneumonia, s. 293. inflammation of the lung, s. 203. three stages of, s. 293. gangrene, s. ^3. case of, iii. 120. cancer of the lung, s. 293. phthisis, s. 293. hepatisation of, in the foetus in utcro, ii. 331. induration of the, iv. 707. modes of cicatrisation of the, i. 604. morbid changes in the lungs after dividing the vagi, iii. 898. softening of the lungs, iv. 707. introduction of black-coloured substances from without into the lungs, iv. 1 17 causes, iv. 1 17. lungs of colliers, disease of, iv. 1 1"^, tubercle in the lung, iv. 104. causes of the lormation of tubercles in the lungs, iii, 754. seat of pulmonary tubercle, s. 293. character of tubercle, iv. 104 ; s. 293, tuberculous masses, iv. 104. infiltrated tubercle, iv. 105. grey tubercle, iv. 105, vellow opaque tuberculous matter in, iv. 105. gelatiniform tubercle, iv. 105. microscopical condition of the yellow tu- berculous 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 particles, 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. analyses of tubercle, iv. 106, 107. growth — mode of enlargement of tubercle, iv. 107. changes wliich tubercle undergoes, 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'Callcd “ transfonnatiou,” iv. 108. by elimination, iv. 108. tubercular cavities in lungs, iv. 108. size of cavities, iv, 109. course and event of cavities, iv. 109. Lttngs, comparative anatomy of the, iv. 331. Lunularia vulgaris, development of, s. 253. Lutrn vulgaris, organs of voice of the, iv 1490. Luxations of the bones of the fore-arm, ii. 69. of the hip-joint, congenital (“original” of the Conti- nental surgeons), ii. 780. of various joints. ^ See those joints, under their head- ings. Lycopodiacecc^ vegetative system of, s. 243. commencement of the development of the prothalUum, s. 243. archegonia, s. 243. embryo, s. 243. sporangia and spores, s. 243. Lycopodium of Peru, dormant vitality of, iii. 156. Lymph, description of, i. 50 j iii. 219. analysis of, iii. 220. microscopic appearance of, iii. 221. analysts of chyle, iii. 222. taken from the thoracic duct, iii. 222. before reaching the thoracic duct, iii. 223. 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 and 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. 203. inner tunic, iii. 208. fibrous tunic, iii. 208. lymph hearts of the lower animals, iii. 20D. external tunic, iii. 209. valves, iii, 209. mode of origin of the lymphatic, ii'. 21 1. 403. lymphatic or absorbent gland?, iii. 217. blood-vessels, iii. 2IH. 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. 210. 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 renma)-y Glands {in comparative anatomy), iii. 251. in the Kangaroo, iii. 251. in the Ornithorhynchus, iii. 251. in Cetacea, iii. 251. number of efferent ducts in various animals, iii. 252. Ma))wiary nerves, iv. 753. veins, iv. 823. internal, iii. 249; iv, 1408. Mammilliform fibrous processes, s. 125. * Mammilla, or nipple, of mamm®, iii. 246. Mammillary bodies, or corpora albicantia, iii, 673. 676. 701. fibrous matter and connexions, iii. 701. structure, iii. 701. processes or papill®, iv. 237. Mammoth (Elephas pritnigenius), 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. Mandihulata, a sub-class of Insecta, ii. 859. Mandrill, anatomy of the, iv. 201, el seq, Mauis, structure of the, ii. 47. See Edentata. electricity of a species of, ii. 82. pelvis of the, s. 164. MantidcB, or praying insects, ii. 864. “ Mantle” of the .acephalous Mollusca, i. 7C5. Mani/plies, psalterium, omasum, or feuillet, of Ruminantia, s. 537. Marasmus, causes of, iii. 752. effects of certain forms of, on the action of the heart, i. 798. Marchantia polymorpha, vegetative system of, s. 237. Marble, iv. 37. radiating lamiii® of, iv. 37. Mare, milk of the, iii. 362. analysis of the, iii. 362. Margarita of the cornea, ii. 177. Marine animals, luminousness of. See Luminousness, Animal. ( Arctomys), anatomy of the, iv. 370, ct seq. Ma)'quesans, physical characters of the, iv. 1362. Mai’row of bones, fat in, i. 58. spinal. See Spinal Cord. Marsupialia, iii. 257- essential external and internal characters, iii. 2-"‘7. general remarks on the geographical distribution, &c. of the Marsupialia, iii. 257. Classification, iii. 258. Tribe I. Sarcophaga, iii. 258. Genus Thylacinus, iii. 2.58. Dasyurus, iii. 2-59. Phascogale, ill. 259. Tiibe II. Entomophaga, iii. 2.59. Group fit, Gressoria. iii. 260. Genus Myrmecobius, iii. 260. Group /3, Saltatoria, iii. 260. Genus Perameles, iii. 260. Chceropns, iii. 261. Group y, Scansoria, iii. 2 >1. Genus Didelphis, iii. 261. 3 G 2 812 GENERAL INDEX. Marsupiama, Classification — continvcd. Tribe III. Carpophaga, iii. 2G2. Genus Phalangista, iii. 262. Petaurus, iii. 263. Pliascolarctus, iii. 265. Tribe IV. Pocphaga, iii. 265. Genus Hypsiprymmis, iii. 265. Macropus, iii. 266. Tribe V, Khiznphaga, iii. 207. Genus Pliascoloniys, iii 267. Osteology of the Marsnpialia, iii. 268. the skull, iii. 268. composition of the cranium, iii. 269. occipital bone, iii. 209. temporal, iii. 209. sphenoid, iii. 271 . parietal, iii. 272. frontal, iii. 272. lachrymal, 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 Thylacotheriuni, iii. 275. vertebral column, iii. 276. cervical vertebrae, lii. 276. dorsal, iii. 277. lumbar, iii. 278. sacrum, iii. 278. caudal vertcbi£e, iii. 278. thorax, iii. 280. ribs, iii. 2R0. 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 ; s. 159. os innominalum, iii. 2H3. 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 muscles in a male Phalanger, iii. 287. external cblique, iii. 287. internal oblique, iii.2>'8. transversalis abdominis, iii. 288. jiyramidalis, iii 288. cremaster, iii. 288. muscles of the pectoral extremity in Peramcles lagotis, iii. 289. trapezius, iii. 2H9. latissimus dorsi, iii. 289. omo-anconeus, iii, 280. serratus magnus. iii. 289, supra-spinatus, iii. 289. dcltoides, iii. 289. subscapularis, iii. 289. teres major, iii. 289. triceps extensor, iii. 289, pectoralis major, iii. 289. biceps, iii. 2s9. pronator teres, iii. 290. flexor carpi ulnaris and radialis, flexor subli- mis digitoriim, iii, 290. flexor profundus, iii. 290. pronator quadratus, iii, 290, supinator longus, iii. 290. muscles of the pelvic extremity, iii. 200. ill the Kangaroo ; sartorius, &c., iii. 290. in a Dasyure ; sartorius and glutei, iii. 290. ill Perameles lagotis; sartorius, rectus femo- ris, and biceps flexor cruris, lii. 200. in Dasyurus macrurus ; plantaris, soleus, tibi- alis posticus, flexor longus pollicis, flexor communis digitorum, iii. 200. in Phalangista vulpinea; muscles of the ante- rior part of the leg, iii. 291. in Perameles lagotis; gastrocnemius, soleus, and plantaris, iii, 201. nervous system, iii. 201. 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. 208 ; iv 933. cheek pouclirs, iii. 209. fauces, iii, 209. Marsupiama, digestive system — conihmed. alimentary canal, iii. 299. sebaceous follicles of the rectum, hi. 303, proper spliincter of the 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. -iaS. absorbents, iii. 305. blood, iii. 305. heait, iii. 306. arteries, iii. 307. veins, iii. 308. respiratory organs, iii. 309. tracheal rings, iii. 309. tliyroid 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. 31 1. vesicultc seminales, iii. 311. membranous and prostatic portion of the urelhra, iii. 311. Cowper’s glands, iii. 311. penis, iii. 311. spermatozoa, iii. 312. erectores penis, iii. 312. retractor penis, iii. 312. levator jienis, iii. 313. sphincter cloacae, iii. 313. Weberian organ, iv. 1418. female organs, iii. 313. ovaries, iii. 313. review of the female generative organs in otlier groups of vertebrate animals, iii. 316. uteri and vaginae in various species, iii. 316. arrangement of the vaginal rugfe, &c., iii. 317. purposes answered by the different forms of the generative organs of marsupial females, iii. 317. gelatino-miicous secretion in the vagina, iii. 318. clitoris, iii. 318. development of Marsupialia, iii, 318. review of tlie different opinions which have been expressed on the subject, iii. 318. experiment performed witli a view to ascertain the 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-gestatiori, 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 foetus of Didelphys Virginiana, and sub- sequent growth of the young, iii. 325. condition of the young Kangaroo wliilst in the marsupium, iii. TJ5. relative size of tlie brain of the embryo Kangaroo compared with that of the embryo of the sheep, iii. 326. traces of the umbilical vessel?, urachus, &c., in the mammary foetus of Kangaroo, iii. 326. dissection of a small mammary foetus of Kangaroo, iii. 326. larynx of the mammary foetus of Kangaroo, iii- 327. maturation of the mammary foetus, iii. 327. mammary organs, lii. 327. marsupium, lii. 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 Marsupiaua, iii. 330. '^larsupiate generation, mode of, ii. 43f>. Marsupium^ or pouch of Marsupialia, iii. 327. development of the, iii. 327. l^Jars-upium nigrum, or pecten in Aves, ii. 2(»3. Mascula Sapplio. ii. 686. !>Iass(i carnea Jacobi Sylvii, ii. 3-)8. Maasetcric artery, i. 4K9. branch oflnlerior 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. miLScles used in, iii. 542. uses of the salivary glands in, iv. 428. function of tlie tongue as an organ of, iv. 1 152. Masticaturij nerve, ii. 271. Mas/i(f, brain of the, iii 696. I\Iastigocerca, a genus of llotifcra, iv. 406. GENERAL INDEX, 813 Nastodon giganteus, anatomy of the. See PAcnYDEUMATA. tusks of the, iv. 927. pelvis of the, s. 156. Tilastoid 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. T^laternal affection, or Iattcr, organic, considered, iii. 152. See Life. Mattirity of man, i. 76. osseous system at, i. 438. Jl/rtw;, etymology of the word, s. 294, note. MaxillcB^ or lesser jaws, of insects, ii. 8b9. office of the, ii. 8S9. of .Arachnida, i. 202- Maxillary^ or inferior dental, artery, 1. 489. external, or facial artery, i. 486 j ii. 227. internal, i. 489 ; ii. 227. 556 ; iii. 93. 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 interinaxillare, ii. 210. structure, ii. 209. surfaces, ii. 207. 1 . facial, ii. 207. 2. posterior, or zygomatic, ii. 203. 3. internal, or naso-palaiine, ii. 208. 4. superior, or orbitar, ii. 208. in the inferior animals, li. 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, inferior, ii. 294. nerve, inferior, i. 749 ; ii. 291, 292. 204. 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, internal, iii. 903. 949 ; iv. 1405. l.UadQws^ ravages of the wire-worm in, ii. 8G1. Meal-heetles (Tenebrionulze), ii. 863. Meandrina cerebriformis, a species of Polypifera, iv. 36. mode of growth, iv. 37. Meandrincp^ genera of Polypifera, iv. 36. ^lcasles^ traces of, in the fcetus in utero, ii. 333. “ Measly pork,” cause of, ii. 120. Meat. See Muscle. Meaty or fl*»sh, as food, s. 389. See Food. Mealus auditorius cartilagineus-membranaceus, ii. 552 development and abnormal conditions, ii. 561. auditorius externus, i. 733. internus, 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. office of the, in the function of hearing, ii. 571. 677. nasal, i. 731. middle, i. 731 ; iii. 725. superior, i. 731 ; iii. 724. urinarius, iii. 914 ; iv. 1244 ; s. 710. of female, iv. 1264. MeckeVs ganglion, ii. 285. 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, iv, 757. Mediastinal arteries, i. 193 ; iv, 822. Mediastinum^ iv. 1. testis, iv. 977. Medical Statistics. See Statistics, Medical, Medicamc7its, action of, on the system, ii. 1.5. iVerfewa, or Guinea, worm, ii. 122. SeeENTOZOAj Filaria Medinensis. Medulla^ or marrow of bones, i. 434. composition, i. 434. condition of, in rickets, i, 440. See lUdcels. 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-po.sterior, iii. 680. 685. arciform, iii. 680. decussating, iii. 680. fissure of, median anterior, iii. 679. posterior, iii. 679. nerves connected with the medulla oblongata, iiL 684. shape, iii. 679. transverse sections of the medulla oblongata, iii. 683. sketch of the microscopic anatomy of the medulla 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. motility and sensation of, i. 41, note t d. organs of digestion in, i. 42. organs of generation in, i. 46. Mediisroof of the physio- logical conformity of the several races of man- kind, iv. 1337. table of cases of first menstruation in Ilindosian and in England, iv. 1338. exciting causes of early menstruation, iv. 1338. office of the uterus in menstruation, s. 662. periods of duraiioii and recurrence, ii. 440 ; s. GG2. quantity of menstrual fluid, ii. 440; s. 663. nature of the catamenial discharge, ii. 440 ; s. 663. composition of the menstrual fluid, analysis, s. 6l3. microscopic examination, s. 663. iinmixed menstrual fluid ; analysis, s. 664. source of the menstrual fluid, s. 665. means by which the blood escapes during healthy menstruation, s. 665. 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. 463. menstrual discharge regarded as an excretion, ii. 150. effects of the suppression of the evacuation of, ii. 1 50. Meyistruation — 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 lactation, ii. 440. character of the various races of mankind, remarks on the, iv. 1342, etseq, foramen, ii. 214. fossa, ii. 211. 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 htemoptoe, i. 232. effect of the protracted use of, on the bones, i. 449. ulcerations of the larynx caused by, iii. 1 19. Mermis albicans, development of ova in, s. [122.] ni,irescens, mature ova of, s. [124.] Mescnceplialc. See Mcsoccphalc. Mesenteric artery, superior, i. 189. 195 ; s. .379. inferior, i. 189. 196; s.380. glands, iii. 943. Mesenteric plexus of nerves, superior, iv. 982 ; s. 420, interior, iv. 1414 j s. 3»1. 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. Mesiaji line, ii. 500. Mesmeric or hypnotic experiments, iv. 694. 696. 703. Mesoce^cnm, i. 14; Iii. 943. Mesocephale, or mesencephale, iii. 668. 677. GS4. corpora qiiadrigemina, iii. 677. 685. plan of section of the mefocephale, iii. 686. pons Varolii, iii. 67*^. 685, processus cerebelti ad te.stes, iii. 677. 685, 686. valve of Vieussens, iii. 678. 6S5, 686. intrinsic and extrinsic elements which enter into the formation of the mesocepliale, iii. 686. functions of the mesocepliale, 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 lelt, i. 14. transverse, iii. 942 ; s. 365. layers, iii. 942, 943. Mesorectu77i, iii. 943 ; s. 380. ISletacarpal, branch of radial artery, ii. 529. iViece, iii. 355. micrometry by means of the camera lucida, iii. 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 aidiiig, i. 17. difficult micturition in cases of disease of the prostate gland, iv. 158. Migration, instincts connected with, iii. 12, 13. migrating pigeons of America, iii. 18. propagation and support of offspring one of the objects 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. 358. 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 nervous system on the secretion of milk, iv. 4Gi. remarkable cases, iv. 465. Milk-tuhes of Mammalia, iii. 248. See Mam.mary 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 deaf, 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. cariiosa, iv. 944. cruenta, iv. 944. fungosa, iv. 944. tendinosa, iv. 944. Molar glands, iv. 426. Mole family (Talpidee), ii. 994, et seq* Mole (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. il/o/e- 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. 120. Molgula, a genus of Tunicata, iv. 1187, et seq. characters of the genus, iv. 1 187. Mollities ossium, or malacosteon adultorum, i. 442; s. 189, 190. causes, i. 442. cases recorded, i. 442, 443. condition of the bones in, iv. 712. Mollusca, iii. 3G3. 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 Tunicaia; 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, 365. touch, iii. 365, 3 G 4 81G GENERAL INDEX Mollijsca — continued. respiratory system, iii, 3Gr>. uropoietic system, iii.SOG. shell of Mollusca, iv. 5G9. integuments of the Mollusca, s. 48S. excretionary int^'gumGnr, s. 488. membranous shell-substance of Dr. Carpenter, s. 489. conversionary integument of the Mollusca con- taining cellulose, s. 493. temperature of, ii. G50. list of Mollusca possessing the property of luminous- ness, iii. 197. See Luminousness, Ammai.. effect of fear on some of the, iii. 7. Nollusca pinnata. See Pteropuda. J^lelolonthido!, ii. 8G0. ?>Ionad atoinos of Muller, ii. 133. Mu7iadinid(v, a family of I’olygastric animals, iv. 3, et seq, cliaracters of the family, iv. 3. Monads (Monadinida?), iv. G. l.o. their extreme minuteness, iv. 6. Mongalla tribe of Africans, woman of the, iv. 1354. languages, iv. 1349. Mongolian race, pyramidal cranium of the, iv. 1322. piiysical characters of, iv. i:Ui4. variety in tlie complexion of the, iv. 1334. See Va- rieties or Mankind. peninsular and hyperborean, characters of the, iv. 1351. Monitor \\z~n<\ of South America, iv. 8'JO. pelvis of the, s. 171. Monkei/s, iv. l'.)5, et scq. See Qu,\drum.\Na. organs and mode of progression of the, iii. 455. brain of, iii. G24. G9G. organs of voice of the, iv. 1487 Monies^ alleged atrophy of the testicles of, iv. 993. Monocera, a genus of iloiifera, iv. 401. Monochitonida^ a sub class of Tuiiicala, iv. 1192, ct scq. Monocuti., ovum of, s. [MG.] Monolttbis, a genus of Uotifera. iv. 407. Monoiuyaria. i. G95. See Conciufera. Islonopodm, iv, 9C4. Mo7iorchides. or persons with only one testicle, iv. 987. Monostoma nmtabile, a species of Treinatode Lntozoa, ii. 142. Monostyln, a genus of Rotifera, iv.40fi. Mo7iotia, or deficiency of the under jaw, iv. 9G7. M'jNotuemata (an order of Mammalia), iii. 3GG. general characters, iii. 366. J'lchitlna, iii. 307. Ornithorliynchus, iii. 3G7. osteology, ill. 3GS. skull, Echidna, iU. 3GS. occipital bone. iii. 360. parietal bone, iii. 309. temporal bone, iii. 370. frontal bone, iii. 370. nasal bone, iii. 370. palate bone, iii. 370. superior maxillary bone, iii. 370. coinjiarison with the skull of various Edentate and Marsupial animals, iii. 371. skull, ()i nithorliynchus, iii. 371. occipital and temporal hones, iii. 371 . parietal and frontal bones, iii. 373. foramina in tlie 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 tlie craniam, iii. 374. interior of the skull, iii. 374. lower jaw, iii. 374. vertebral column, iii. 374. true veriebrcG, iii. 374. ribs and costal cartilages or sternal ribs, iii. 375. sternum, iii, 375. sacrum, iii. 375. caudal vertehrje, iii. 375. pectoral extremities, iii. 37G, ])elvic extremities, iii. 378 ; s. IGl. muscular system, Ornithorhynchus, iii. 3.79. nervous system, iii. 382. brain, Ornithorhynchus, iii. 382. Echidna, iii. 382. spinal cord, Ornithorhynchus, iii. 385. Echidna, id. 385. olfactory nerves, Ornithorhynchus, iii. 385. Ecliirina, iii. 38'-*. optic nerves, iii. 385. eye, ill. 385. third and fourth pair of nerves, iii. 386. fifth pair, iii. 38G. sixth and seventh pair, iii. 386. acoustic nerve, iii. 38G. ear, iii. 386. eighth and ninth pair of nerves, iii. 386. brachial plexus, median nerve, iii. 387. lumbar plexus, ischiadic nerve, iii. 387. digestive system, iii. 387 ; s. 304. alimentary canal, Ornilliorbynchus, iii. 3S7. Echidna, iii. 387. Monotremata, digestive system — continued. salivary glands, iii. 383 j 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. vena? cavje and renal veins, iii. 391. portal vein, iii. 391. respiratory system, iii. 391. lungs, iii. 391 trachea, iii. 391. l.irynx, hi. 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, hi. 391. testicle, iii. 392 penis, iii. 392. levator and retractor muscles, hi. 092. Cowper’s glands, hi. 392. female organs, iii. 393. ova of, s. 90. ovaries, iii. 394. Fallopian tubes and uteri, iii. 394. uro-genital canal, ih. 394. common vestibule, ih. 395. . clitoris, iii. 395. Cowper’s glands, iU. 395. products of generation, iii. 395. ovum, iii. 395. the young — Ornithorhynchus — external cha- racters, iii. 399. dissection, iii. 399. mammary organs, iii. 402. crural gland and spur, iii. 405. Monotj'cmatous generation, mode of, ii. 437. Moris Veneris, s. 2 ; i. 708. Monstrosity. See '1'eratology. Monura, a genus of Rotifera, iv. 406. Moon-fish (Telrodon mola), nervous system of the, iii. 615. Moral faculties in animals generally, i. 144. Morbus coxa?, ii. 789; iv. 434. case of, ii. 789. morbus cox*e senilis, ii. 793. Mormo maura, nervous system of the, iii. 612, 613. Morocco^ Southern, characters of the Shelahs of, iv. 1357. Morsus diaboli, or fimbria?, of Fallopian tube, s. 602. Mortality^ rate of, iv. 1473. Mortification of arteries, i. 239. of bones, i. 453. exfoliation, i. 453. necrosis, i. 453. of the hone of the cranium, I. 756. See Necrosis. Moschus, tlie, s. 508. cranium of, s. 511. Mosses^ vegetative sy.stem of the, s. 237. germination of the spore, s. 238. development of tlie antheridia and the archegonia, s. 238. in the genus Phascum, s, 238. development of the fruit, s. 27:8. sjiores, s. 239. dormant vitality of, iii. 156. Motacilla (red-start), nervous system of the, hi. 622, Mother of -pearl, formation of, i. 712. Molhei-'s mark, or nsevus maternus, i. 242. Moths, ii. 866, 867. See Lrpidoptera. changes from the larva state into tliat of the perfect insect, ii. 874, et seq. mode of flight of, iii. 421. Motion, Animal; Animal Dynamics; Locomotion ; or Progressive Motion of Animals, ih. 407. general remarks, iii. 407. Sect. 1. Fundamental axioms, hi. 408. composition and resolution of forces, iii. 408. parallelogram offorces, iii- 408. polygon of forces, iii. 408. parallelopipedon of forces, iii. 408. centre of gravity, iii. 409. the lever, ih. 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 efi'ects of fluids on animals immersed in them, iii. 412. resistance of fluids, hi. 413. passive organs of locomotion, iii. 413. bones, hi. 413. joints, iii. 415. ligaments, ih. 415. muscles, hi. 416. force of musclc.s at various stages of their con- traction, iii. 418. GENERAL INDEX, 817 Motion, continued. Sect. II. Flying, iii. 419. flight of insects, iii. 419. Coleoptera, iii. 421. Dennaptera, iii. 421. Lepidoptera, iii. 421. nocturnal Lepidoptera, iii. 422. Neuroptera, iii, 423. Uymenoptera, iii. 423. Liptera, iii. 423. table showing the areae of the wings and 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 aniin.ils, iii. 429. Dactvlopterus and Exoc$tus, iii. 429. Draco volans, iii. 429. Galeopithecus and Pteromys, iii. 430. Pterodactylus, iii. 430. Cheiroptera, iii. 430. amount of force necessary for aerial progression, iii. 431. Sect. III. Swimming, iii. 431. ciliograde animals, iii. 432. Porifera and Polypifera, iii. 432. cirrigrade animals, iii. 433. pulmograde animals, iii. 433. syringograde animals, iii. 433 ; iv. 1241. vermiform animals, iii. 434. aquatic insects, iii. 434. Decapods, iii. 436. Cephalopods, iii. 436. Pteropods, iii. 436. Pisces, iii. 437. shaped like the salmon, cod, and mackerel, iii. 437. flat fishes, hi. 437, analysis of the act of swimming in fishes, iii. 438. aquatic birds, iii. 438. quadrupeds, iii. 439. Man, iii. 439. Sect. IV. Progression on solids, ill. 440. Radiata, iii. 440. Echiuida, iii. 440. Annelida, iii. 441. Insecla, iii. 441. apode larv$ of insects, iii. 441. pedate larva?, iii. 441. ]ierfect 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. LacertiB, iii. 449. Chelonia, iii. 450. birds, iii 450. mammiferous quadrupeds, iii. 451. horse, iii. 452, walk, trot, gallop, iii. 452. Marsupialia, iii. 453. Rodentia, hi 454. Ruminantia, iii. 454. Proboscidia, iii. 454. Carnivora, iii. 455. Cheiroptera, iii. 455. Quadrumana, iii. 455. Sect. V. Man, iii. 456. the vertebral column, iii. 456. the legs, iii. 457. walking, iii. 459. tables of the measure of inclination of trunk in various modes of j^rogression, 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. T^Iotion, muscular, iii. 516. See Muscular Motion. Motions of joints, i. 255, 256. abduction, i. 256. adduction, i. 236. 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 oculorum nerves, iii. 707. Moult, or renovation of the tegumentary skeleton 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 Insecta. of Marsupialia, iii. 297. Mozablie Arabs of Algiers, portraits of, iv. 1357, Mozambique, native of, iv. 1354. Muciparous follicles of vulva, s. 711. Mucous fluid lubricating the bladder, i. 586. glands of the longue, iv 1140. Mucous Membrane, iii. 484. definition, iii. 484. ultimate structure of the mucous membrane, iii. 4S6. basement membrane, hi. 486. of kidney, iii. 486. testis, hi. 487. salivary glands, iii. 487. liver, iii. 487. pulmonary air-cells, hi. 487. alimentary canal, iii. 487. skin, iii. 488. cutaneous follicles, ii. 4S2 ; iii. 489. epithelium, hi. 489. lamelliforra or scaly variety, iii. 489. prismatic, iii. 490. spheroidal, hi. 491. non-ciliated and ciliated, iii. 492. elementary tissues appended to the mucous system, iii. 492. 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. 495. gastro-pulmonary tract, iii. 495. genito-urinary tract, iii. 495. peculiarities of the skin, mucous membranes, and glands, iii. 496. skin, iii. 496. mucous membranes, iii. 496. glands, iii. 497. liver, iii. 497- kidneys, iii. 498. testis, iii. 498. salivary glands, iii. 49S. 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 difierent 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 hccmorrhage 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 crecuin, s. 363. of the colon, s. SG8. 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, hi. 733, 739. of the cesophagus, iii. 759. of small intestine, s. 343. valvulffi conniventes, s. 346. intestinal tubes, or follicles of Lieberkiilin, s. 346. villi, s. 350. intestinal follicles, s. 356. agminate, s. 356. solitary, s. 360. racemose, or Brium’s, glands, s. 361. of the stomach, s. S2U. rugfe, 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, s.322. tubes at the pyloric extremity of the organ, s. 322. 818 GENERAL INDEX, Mucous meynbrane — continued. tracheal, s. 259. ofurethra, iv. 1249. 1250. of the uterus, s. 655. Mucous ijolypi of the nose, iii. 740. Mucus, iii. 481. detinition, 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 winch the term mucus should be a[>pUcd, iii. 483. analyses of ovarian effusions, eliusion 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. Mugillidcc. a family of Fishes, iii. 957. flutes, 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. Muller, duct of, s. 594. 597. hl3. Multijhlus spinaj muscles, i. 374. ill tlie loins, s. 137. Mumps, or cynanche parotidei, iv. 430. effect of mumps on the testicle, iv. 993. Muntjak, or Kijang (Cervus muntjac), s. 508. cranium of, s. 512. Murania conger, or conger, tongue of the, iv. 1146. Mas rattus, anatomy of the, iv. 371, ct seq. spermatozoa of the rat, iv. 476. jaculus, or alactaga, anatomy of the, iv. 372, ct scq. porcellus, or guinea-pig, anatomy of the, iv. 372, ct seq. Musca domestica (or house-fly), powers of flight of the, iii. 4^-4. 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.] Musenrdin (M. avellenarius), anatomy of the, iv. 386, et scq. digestive organs of the, s. 303. MuscuUv, or common house-flies, iii. 867. Musci.e, iii. 506. definition, iii. 506. general description of muscular tissue, iii. 506. characteristics of voluntary and involuntary muscles, i 710 ; iii. 506. contractility, i. 717. See Contractility. a. striped elementary fibre, ii. 259 ; iii. 506. 1. length, iii. 507. 2. thickness, lii. 507. 3. figure, iii. 507. 4. colour, iii. 507. 5. internal structure, iii. 508. microscoj)ical aj>pearance, iii. 508. transverse stripes, id. 508. longiiudinal lines, iii. 508. discs, iii. 508. librilla?, 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, id. 513. 8. attachment of the extremities of the fibres to other structures, iii. 513. 0. development, iii. 513. h. uustriped 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. venajcomitcs accompanying 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. f. chemical constitution, i. 719; iii. 519. See also Fi- BUINE. historical sketch of, iii. 527 — 529. relaxation of the, a sign of approaching death, i. 800. action of acids upon muscular fibre, ii. 259, 2GU. fibres of the urethra, .supposed, iii. 915. comparison of the structure of striped muscle with that of the ccrebro-spinal nerve, iii. 693. Muscle (morbid states of). See Heart (morbid states of I tlie) ; and Hypertuopii v and Atpopiiy. atrophy of muscles, various causes of, iii. 752. abnormal conditions of the muscles in chronic strumous i, arthritis coxa?, ii. 797. : unhealthy formation of fat in the muscles, voluntary and involuntary, iv. 96. microscopic parasite of the human, ii. 113, 114, i Muscles of particular organs, parts, or regions. See those i organs, parts, or regions. I in infancy, i. 79. | in old age, i. 79. Muscles in particular : — ;! abdominal, i. 16. i abductor minimi digit! manils, ii. 520. pedis, ii. 358. pollicis mantis, ii. 519. ]>edis, ii, 358. acceleratores urina?, iii. 915. 929 ; iv. 1255 , s. 138. adductor brevis femoris, s. 137. ! longus lemoris, s. 137. i magnus femoris, s. 137. ossis metacarpi, ii. 521. pollicis manCis, ii. 520. pedis, ii. 358. 1 ancona?us, ii. 65. 368. I anomalus of Albinus, iii. 729. | of ankle, i. 150. of anus, i. 175 ; s. 369. ' aryteno-epiglottidei, iii. 110. arytenoid, iii. lUl. 107.| attoliens auriculam, ii. 551. i attrahens auriculam, ii. 552. clitoiidis, s. 713. auricular, i. 749. azygos uvula?, iii. 952. basio-glossus, iv. 1133. I biceps flexor cubiti, i. 216, 217. 359 ; ii. 63. 163. 264. 363: iv. 575, 576. ' | cruris, vel femoris, iii. 44; iv. 61. 1118: i s. 137. ' biventer cervicis, i. 372. brachialis anticus, i. 217. 219; ii. 64, 65. 160.363: iv. ' 756. j, externus, i. 220. ! canine, ii. 224. j; cerato-glossus, iv. 1133. cervicalis dcscendens, i. 372. j chondro-glossus, iv. 1133. i circumflex i>alati, iii. 951. ,! coccygco-anal, i. 176. ; complexus, i. 373. 732. compressor narium minor, iii. 729. f n.isi, iii. 728. I uretline, iii. 952; iv. 1247; s. 138. I vciue dorsalis penis, ii. 446; iii. 916. I constrictor ani, i. 176. ! i>thmium faucium, iii. 952; iv. 1133. of larynx, inferior, iii. 102. pliaryngis inferior, iii. 946. medius, iii. 946. superior, iii. 946. vaginte, s. 712. coraco-brachialis, i. 217. 219. 359 ; ii. 160 ; iv. 756. ' corrugator sui>ereilii, i. 748; ii. 222 ; iii. 80. costo-abdominal, i. 4*. of cranium, i. 747. 749. cremaster, i. 6. 8 ; iv. 982. 984. cnco-arytenoidei postici, iii. 101. 109. iaterales, iii. 101. 107. crico-thyroid, iii. 101. 105. deltoid, i. 216. 3.19 ; ii. 159, 160 ; iv. 435. 571. depressor ala; nasi, ii. 223 ; iii. 728. anguli oris, ii. 224. labii inferioris, ii. 225. | septi nariiim, iii. 729. i uretlu'cC, iv. 1264. I detrusor iirina;, i. 381. I of diaphragm, ii. 1 ; iii. 544. j costal, or greater, ii. 2. ! vertebral, or smaller— crura, pillars, or appendices, ! ii. 3. digastricus, iii. 105. 563. dilator narium, iii. 728. anterior, iii. 729. posterior, iii. 729. 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. cUtoridis, s. 138. 709. spime, i. 372. extensor brevis digitorum pedis, ii. 357. carpi radialis brevior, ii. 369. longior, i. 217 ; ii. 160. 366. carpi ulnaris, ii. 369. coccygis, s. 137. communis digitorum, ii, 369 ; iii. 131. longus digitorum pedis, ii. 352; iii. 137. ossi metacarpi pollicis, ii.369. GENERAL INDEX. 819 Muscles in particular — extensor proprius pollicis pedis, ii. 352 ; iii. 137. primi digiti manCls, ii. 370. primi internodii, ii. 370. sccundi internodii pollicis, ii. 370. flexor brevis digitorum pedis, i. 150 ; ii. 358. minimi digiti p^is, ii. 358. minimi digiti inanOs, ii. 520. pollicis manOs, ii. 520. pedis, ii. 358. carpi radialis, ii, 361. 365, 366. ulnaris, ii, 367. communis digitorum perforatus, ii. 367. digitorum profundus perlorans, ii. 368. digitorum accessorius pedis, ii.358. communis, iii. 133. longus digitorum, iii. 139. pollicis pedis, i. 150; iii. 133. HO. ossis metacarpi, ii. 519. perforatus pedis, ii. 358. of fore-arm, ii. 65. 365. frontal, i. 747. fronto-nasal. See pyramidalis. gastrocnemius, ii. 357 ; iii. 127. 132, 138 ; iv. 62. gemellus inferior, 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 ; s. 137. medius, ii. 833 ; s. 137. minimus, ii. 833 ; s. 137. gracilis, s. 137. Guthrie’s, iii. 930 ; iv. 1264. helicis major, ii. 552. minor, ii- 552. hyo-glossus, iii. 105. 565; iv. 1133. hyo-thyroid, iii. 102. iliacus internus, i. 11 ; s. 137. ilio-abdomiiial, i. 6. ilio-lumbo-costo-abdominal, i. 6. ilio-pubUcosto-abdominal, i. 4*". indicator, ii. 370. infra-costales, iv. 1056. infra-spinatus, i. 217 ; iv. 436. intercostal, external, iv.334. 1013. internal, iv. 334. 1043. action of, iv. 1044. interossei manOs, ii. 521. dorsales, ii. 521. ' palmares, ii. 521. pedis dorsales, 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-pehnealjiii. 929. of joints, i. 253. lachrymal, or tensor tarsi, iii. 92. of larynx, extrinsic, iii. 105. intrinsic, iii. 105. latissimus colli, iii. 566. dorsi, i. 4*, 5. 217.362 . 368; iv. 435. 576; s. 137. laxator tympani, i. 728. of leg, iii. 137. levator anguli oris, ii. 224. scapulas, i. 370 ; iv. 576. labii superioris, ii. 224. aleeque nasi, ii. 222. menti, ii. 225. palati, i. 734 ; iii. 951, 952. palpebr® superioris, ii. 222 ; iii, 79. 82.784, 788. prostatae, iv. 147. levatores ani, iii. 944; iv. 1246 ; s. 138, 369. costarura, iv. 344. breviores, iv. 1055. longiores, iv. 1055. lingual, iii. 544.565; iv. 1126. transverse, iv, 1126. lateral, iv. 1126. . inferior, iv. 1126. longitudinal, iv. 1126. oflips, ii. 223. longissimus dorsi, i. 10. 372; s. 137. longus colli, iii. .561. lumbo-abdominal, i. 7. lumbo-ili-abdominal, i. 7. lumbricales manus, ii. 521. pedis, ii. 358. malleus, external, great, ii. 548. muUifidus spince, i. 374 ; s. 137. mylo-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 ; s. 137. ascendens, i. 6. descendens, 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, 7sL 789. obturator externus, s, 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. palpebrarum, ii. 221 ; iii. 80, 81. of orbit, iii. 784. orbito-palpebral, ii. 222. palato-glossus, iii. 952; iv. 1121. 1133. palato-pbaryngeus, iii. 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 ; iii. 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. 5n6. of popliteal region, iv. 61. popliteus, iii. 139 ; iv. b2. pronator quadratus, ii. 368. radii teres, ii. 63. 566. psoas magnus, i. 10 ^ ii. 838 ; s. 137. parvus, i. 11 ; iii. 838; s. 137. pterygoid, i. 727. pyramidalis abdominis, i. 10; s. 137, nasi, ii. 222 ; iii. 728. pyrifbrmis, s. 137. quadratus femoris, s. 138. lumborum, i. 10; s. 137. menti, ii. 225. quadriceps extensor, iii. 77. recti capitis amici 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. 7S8. rectus capitis lateralis, i. 732 ; iii. 561. femoris, s. 137. superior, iii. 784. retractor anguli oris, iii. 5G6. retrahentes auriculam, ii. 552. rhomboidei scapulce, iv. 576. rhomboideus major, i. 370; iii. 729 ; iv. 755. minor, i. 370. risorius Santorini, iii. 566. sacro-coccygean, anterior, s. 122. posterior, s. 122. sacro-lumbalis, i . 10. 372; s. 137. sacro-spinalis, i. 10. sartorius, s. 137. scalenus ar.ticus, iii. 562; iv. 335. 817. posticus, iii. 562 ; iv. 335. 817. minimus, iv. 817, of scapular region, iv. 433. semi-membranosus, iv. 61. semi-spinalis dorsi, i. 372. colli, i. 373. semi-tendinosus, ii. 2W ; iv. 61 ; s. 137. serratus magnus, i. 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,!. 176; s. 369. internus, i. 176, 177 ; s. 13S. 369. oris, ii. 233. vaginae, s. 138. spinalis, or semi-spinalis, colli, i- 373. dorsi, i. 372. splenius capitis, i. 371. colli, vel ccrvicis, i. 371. sterno-costalis, iv. 1055. sterno-cleido-mastoideus, i. 734; iii. 565; iv. 817. sterno-hyoid, i, 483; ii. 851 ; iii. 102. 105. 562; iv. 1022; s. 259. 820 GENERAL INDEX. Muscles in particular — can/inued. sterno-inastoid, i. 749; ii. 851. sterno-thyroid, I 483; ii. 851 ; iii. 105. 5G3 ; iv. 1022; .8. 259. subclavius, i, 360 ; iv. 755. sub^capular, i. 362 ; iv. 755. supinator radii brevis, ii. 369. radii longus, i. 217 ; ii. 63. IGO. 3G5. stylo-"lossus, i. 734. stylo-hyoideus, i. 734; iii. 105. 5G4. stylo-pharyngcus, iii. 947. temporal, i. 729. 734. 7-19. tensor membraiia tympani, i. 73-1. palati, i. 727 ; iii. 951. tarsi, iii. 92. tympani. i. 734; ii. 548. 574. vaginae femoris, ii, 264 ; s. 157. teres major, i. 217. 360. 362 ; iv. 43G. minor, i 217 ; iv. 436. thyroid, iii. 101. thyro-arytenoideus, iii. 108. thyro-epiKlottideus, iii. 110. tliyro-hyoideus, iii. 105. 5G3. of testicle. See Cref?2aster. tibialis anticus, ii. 352; iii. 151. 137. posticus, iii. 1.33. 140. of tongue, iii. 504. 565 ; iv. 1125. of trachea, s. 262. traclielo-mastoideus, i. 373. 732. 734. transversalis abdominis, i. 7. 17; ii. 840; s. 1.37. colli, i. 373. I edis, ii. 358. transversus perinei, s. 138. trapezius, i. 369. 732; iv. 434, 4.35. 476. triangularis nasi, ii. 222 ; iii. 728. oris, ii. 225. sterni, iv. 1022. 10.55. triceps extensor cubiti, i. 216, 217. 362. sura} of Meckel, iii. 132. 139. urethral, iv. 1247. 1251. vastus extcrniis, iii. 44. internus, iii. 44. vertebral, or smaller, of diaphragm, ii. 3. ^Vil^on’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 Ilaller. iii. 519. 2. source of contractility — wlience 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 ammal kingdom the vascular supply is accurately proportioned to tlie 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 fibrills, iii. 523. 2. on active and passive contraction, iii. 524. ])assive 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. 52n. development of heat, iii. .526. appearances presented by ruptured muscle, iii, 526. 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, cf scq. Muscular IMotion — co?ili/iucd, mental and physical stimuli, i. 718. See Contractility. Muscular System (in comparative anatomy) shown to ho in conformity with the development of the nervous system, iii. 530. non-existent in the Acrita, iii. 533. as ai)parent in Rryozoa, iii. 535. in Ccelehnintha, iii. 534. in Echinodermata, iii. 537. Encrinus, Comatula, iii. .537. Asterias, Echinus, iii. 537. llolotiiuria, Siponculus, iii. 537. in Epizoa, iii. 536. in ilcterogangliata, 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 R.ays, iii. 543. in Lepido-siren, iii, 543. in Siren lacertina, iii. 543. in Proteus, iii. 543. in Ophidia, iii. 543. in Sjuria, iii. 543. muscles used in mastication, iii. 543. nasal system, iii. 544. ocular system, iii. 544. opercular system, iii. 544. tegumentary system, iii. 543. vertebial s>stcm, 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 lamina? of the bladder, i. 380. tissue, elements of tlie, i. 126. See Muscle. of auricles, ii. 593. of ventricles, ii. 590. Musculi papillares, ii. 581. 601, pectinati, ii. 580. il/«scw/o-phrenica artery, iv. 823. i^i^^i•c^^^-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. 3/i/scw/u-spiral artery, ii. 160. nerve, i. 217. 361 ; iv. 758. branches : internal cutaneous, iv. 759. for the internal liead 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 brancii, iv. 759. internal terminal branch, iv. 759. deep terminal branch, iv, 759. Mtfshrooms, 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 Uie reeds of, iv. 1481. Musk, i. 482. Musk-deer, the, i. 508. Musk-gland of the crocodile, iv. 325, MussM, sea, description of the, i. 621, 622. ciliary motion in tlie, i. 622. in the embryo of, i. 627- nervous system of the, iii. 6(^4. j)reparations of the nerves of, iii. 605. Mustard considered as food, s. 395. MusieluLv, or Weasel tribe, dentition of the, iv. 913. Mutto7i fat, chemical characters of, ii. 223. Mycetes, a genus of Quadrumana, iv. 210, et seq. See Quadriimana, characters of the genus, iv. 210. Mycodermatous vegetations, iv. 144. T^IycUtis, characters of the urine in, iv. 1291. Mygalc, nervous system of the, iii. 6(*9. ?iIylodon robustus, pelvis of the, s. 162, 163. iV^'/o-hyoid groove, ii. 214. muscle, iii. 105. 564. action and relations, iii. 564. ridge, ii. 214. Myopia, or near sight, i'L 1432. GENERAL INDEX. 821 Myopia — coniinved. causes, iv. 1463. usual course of the affection, iv. 1464. treatment, iv, 1464, 1465. myopic spectacles, iv. 1466, 1467. Myopotamus^ or conia, anatomy of the, iv. 373, et seq. Myoxus, or dormouse, anatomy of the, iv. 376, et seq. Myrianida fasciata, mode of reproduction of, s. 33. Myriahoda, 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. 6( 9. 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. 198. Myriapoda chilognatha, iii. 545. Myrmccobius, a genus of Marsnpialia, iii. 260, et seq. characters of the genus, iii. 260. fasciatus, iii. 260. Myrmecophagay or ant-eater, its mode of taking its prey, iii. 8. MijrmelconideB^ or ant-lions, ii. 865. Myrtiform fossa, ii. 207* muscle, ii. 223. Myiilus (mussel), nervous system of the, iii. 604. preparations of the, iii. 605, Myxina glutinosa, or hag-fish, iii. 976. teeih and parasitic habits of, iii. 976. N. Navus maternus, or mother’s mark, i. 242 ; ii. 333. classification of neevi, i. 243. speculations as to structure of, i. 243. vascular naevi of the face, ii. 22& yaides, organs of circulation in the, i. 650. Nails, structure of, s. 477. adventitious formation of, iv. 139. 143. of cats, i. 255. Najay asps or hooded snakes, poison fangs of, iv. 291. Nape of the neck, or nucha, i. 367. furunculi in the, i. 368. Narcotics, efiects of, on the heart and bowels, iii. 50. on nervous system, analogous to dreaming, iv. 690. Nares internse, or cav30 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. 4S7, 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. surfaces, 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. plicae and villi, iii. 92. secretion, iii. 92. structure, hi. 92. fossae, i. 731 ; ii. 212 ; hi. 723. infundibulum, iii. 724. internal, or ethmoidal, branch of the fifth pair of nerves, iii. 733. lamella, i. 731. meatuse.s, i. 731. inferior, iii. 725. superior, hi. 724. muscles, ii. 222. nerve, ii. 281 ; 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. 203. 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 muscle, iii. 729. relations and actions, hi. 729. A’dfw- labial is muscle, ii. 224. ATz^o-lobar nerve, ii. 282. Nh.‘fo-maxillary, or anterior border of superior maxillary bone, ii. 209. A^(Z50-orular nerve, ii. 281. Niwa.palatine ganglion, ii. 257. 371. nerve, ii. 282. or internal surface of superior maxillary bone, ii. 208. Natatores, or swimming-birds, characters of, i. 269. pelves of, s. 168. Natchez Indians, remarkable custom of the, iv. 1360. Kates (of brain), iii- 677 . 685. Nausea, sensation of, ii. 26. causes of, ii. 27. vomiting, ii. 26. Nautilidie, 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*. NenPs-foot oil, chemical characters of, ii, 233. Nebulce of the cornea, h. 177. Neck., iii. 561. definition, iii. 561. I. Muscles, iii. 561. a. anterior vertebral group, iii. 561. longus colli, iii. oil. 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-glossns, iii. 564. stylo-glossus, iii. 565. genio-hyo-glossus, iii. 565. lingualis, iii. 565. genio-hyoideus, iii. 565. . e. superficial on the side of the neck, iii. 565. sterno-cleido-mastoideus, iii. 5G5. platysma myoides, iii. 566. risorius Santorini, iii. 566. II. Fascise, ii. 230; iii. 566. superficial or subcutaneous areolar tissue, iii. 5G6. cervical, iii. 568. ])rc-vertebral, iii. 569. cervico-thoracic septum, iii. 570. III. Regional or surg'cal anatomy, iii. 570. su[)erficial veins and nerves, iii. 571. 1. mesial region of the neck, iii. 572. laryngotomy and the parts concerned, iii. 573. tracheotomy and the parrs concerned, iii. 574 crico-tracheotomy, iii. 574. 2. antero-inferior triangle, iii. 574. thyroid body, iii. 575. bronchocele, iii. 575. asophagotomy, and the parts concerned, iii. 576. 3. antero-superior triangle, Ui. 576. glandulffi concatenatae, 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. 5S2. 8. relations of the sterno-cleido mastoidcus, iii. 583. 822 GENERAL INDEX. Neck — continued. Tractical observations relating to the anatomy ami 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, 953. l^eck of rib, iv. 1026. of the scapula, iv. 573. Kecropkaga, a sub-tribe of Coleoptera, ii. S60. 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 tlie 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. 61. displacements occurring in chronic necrosis in the vicinity of the knee, lii. 65. Negrito race, physical and mental characters of the, iv. 1362. Negroes^ characters of the. iv. 1352. cli.'itinclive characters of the crania of, iv. 1321. portrait (ff young Negro of JJenguela, iv. 1321. characteristics of the brain of, iii. ca[)acity and weight of skull of the Negro, iii. 666. comparison of the Negro brain with that of other races, iii. 666. anatomical conformation of the Negroes, cited as an ex- ample of the permanence of the physical charac- ters of races, iv. 1329. proofs to the contrary, iv. 1329. size of the pelves of Negroes compared with those of Europeans, s. 148. causes of the tendency to extinction in the African races, iv. 1341. 1341. psychical characters of Negroes, iv. 1344. Semitic affinity of the Negro nations, iv. 1353. Negroes liable to anorthopia, iv. 1402. Nigh of tlie horse, iv. 1492. Ncmatoideny an order of Entozoa of Rudolphi, ii. 116. Sec Entozoa ; Sterelminiha. formation and fecundation of ova of, s. [123.3 Nematoncura^ characteristics of, i. 47, 48. organs of digestion of, s. 29 >. ova of, s. [12U.3 Nepa cinerea, or water-scorpion, ii. 868. Nephritis, acute suj)purative, iv. 257. desquamative, iv. 257. clironic, iv, 258. characters of the urine in nephritis, iv. 1201. Nereis, muscles of the, iii. 538. Nekm:, iii. .591. structure of cerebro-spinal nerves, iii. 591. neurilemma, iii. 591. ultimate nervous fibre, 591. tubular membrane, iii 591. white substance of Scinvann, iii. 592. flattened band of Remak, iii. 592. changes produced by the action of water and other re-agents, iii. .592. varicose appearance of nerve-tuhes, iii. 593. table of measurements of nerve-tubes in Man and the other Vertehrata, iii. 593. absenceof anastomoses in nerve-tubes, iii. 593. comparison of nervous with muscular tissue, iii. 593. branching of nerves, iii. 594. anastomosis, iii. 594. decussation of the primitive fibres within the trunk of a nerve, iii. 594. anastomosis of descending branch of the ninth nerve with the cervical plexus, iii. 594. commissure of optic nerve, iii. 595. aiiastomo>is by fusion ; Volkmann's observations, iii 595, nervi nervorum, iii. 595. plexuses, iii. 595. ongin of nerves, iii. 595. See also Nervous Ce\- THES. in muscle, iii. 596. peripheral expansion of nerves on sentient sur- faces, iii. 596. papilla? of the skin, iii. 596. retina and optic nerve, iii. 596. olfactory nerves, iii. 597. the auditory nerve, iii. 597. structure of the ganglionic nerves, iii. 5D7. neurilemma, iii. 597. ramification, iii. 597. peripheral distribution, iii. 598. ))lcxuses, iii. 598. nerve-tubes, iii. 598. cells, iii. .598. gelatinous fibres, iii. 599. difTerence between the structure ofthesympnthetic and the ccrebro-spinal fibre, iii. 599. Nerve — continued. nerves of the Invertebrata, iii, 600. development of nerve, iii. 600. recapitulation, iii. 601. Nervous System, iii. 585. general observations on the disposition and composi- tion of nervous matter, the nature of nervous ac- tions, and the subdivisions of the nervous system, iii. 5S6. nervous matter, iii. 586. how disposed through the animal kingdom, iii, 5Sfi. chemical composition, 587. Vauquelin’s analysis, iii. 587. Fremy’s method of analysis, iii. 587. cerebric acid, iii, 587. oleophosphoric acid, iii. 587. cholesterine, iii. 588. variation of the quantity of phosphorus in dif- ferent periods of life, and its small amount in idiotcy, iii. 588. L'lleritie’s analyses of cerebral matter of in- fants, youth, adults, old men, and idiots, iii. 588. ncrvou.s actions, iii. 588. mental nervous actions, iii. 588. actions of perception, in. 588. common sensibility, iii. 588. special sensibility, iii. 589. actions of emotion, iii. 589. physical nervous actions, iii. 589. contraclion of the iris occasioned by the stimu- lus of light, iii. 589. deglutition, iii. 589. excitement of the respiratory muscles by the sudden application of cold to the surface of the body, iii. 589. reflex action, iii. 590. anatomical subdivision of the nervous system ; — brain, spinal cord, and ganglions, iii. 590. the nerves in infancy, i. 72. conditions furnished by the nervous system to the maintenance of the contractile power of muscles, i. 722. influence of the nervous system upon the circulation, i. 679. See Circulation ; Contractility; Heart. relation between the nervous and absorbent systems, i. 34. elasticity of nervous matter, ii. 60. influence of the nervous system on the secreting pro- cess, iv. 464. theories as to this influence, iv. 469. reflex nervous action, iii. 5, note. Nervous System (comparative anatomy), iii. 601. in the Acrita, iii. 601. in the Polypifera, iii. GOl. Actinia, lii. 601. in the Radiata, in. 602. in the Mollusca, lii. 603, Tunicata, iii. 603. Ascidia maminillata, iii. 643 I'hallusia intestinalis, iii. 603. Conchifera, iii. 603. Gasteropoda, iii. 605. Limpet (Patella), iii. 605. Chiton inarmoratus, iii. 606. Aplysia, iii. 606. Scylla?a pelagica, iii. 606. Limax ater, iii. 606. in the Articulata, iii. 606. Ilelminthoid Articulata, Hi. 607. Entozoa, iii. 607. Rotifera, iii. 607. Cirropoda, iii. 607. Annelida, iii. 607. Entomoid Articulata, iii, G08, Crustacea, iii. 6(i8. Myriapoda, iii. 609. Arachnida, iii. 609. Insecta, iii. 609. See also Tnsecta. Ranatra linearis, iii, 610 Geotrupes stercorarius, iii. 610. Dyticus marginalis, iii. 611. Saturnia pavonia minor, iii. 611, 612. Mormo Maura, iii. 6 >2. motor and sensitive function of ganglionic and non-ganglionic cords, iii. 613. concluding general remarks, iii. 614. in the Vertehrata, iii. 614. Pisces, lii. 614. anatomy of the Amphioxus lanceolatns, iii. 615. neuro-skeleton, iii. 615. nervous system, iii, 615. brain of Fishes, iii. 618. weight of the brain compared with that of the body, iii. 618. olfactory tubercles, or first cerebral mass, iii. H18, oi)tic lobes, or second cerebral mass, iii. 619. cerebellum, or third cerebral mass, iii. 619. GF.NERAL INDEX. 82i Nervous System, Vertebrata — continued. Amphibia and ReptiUa, i. 100; iii. 620. brain, iii. 620. weight compared with that of the body, iii. 620. olfactory tubercles, iii. 621. brain and spinal cord of lizard, iii. 621. optic lobes, iii. 621 . cerebellum, iii. 621. Aves, iii. 621. brain, iii. 622. weight compared with that of the body, iii. 622. cerebral hemispheres, 622. optic lobes, iii. 622. cerebellum, iii. 623. Mammalia, iii. 623. table of the relative proportions of the brain and spinal marrow in the tour classes of Verte- brata, iii. 623. table of relative proportions of body and brain in the four classes of Vertebrata, iii. 62-t. cerebral hemispheres, iii. 624. corpus callosum, iii. 625. ventricles of brain, iii 625. olfactory nerves, iii. 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., of animals. Nervous Centres (in human anatomy), ill. 626. definition, iii. 626. general and descriptive anatomy of the nervous centres, iii. 627. Coverings of the nervous centres, iii. 627. of tlie 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. 629. tentorium cercbelli, 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, lii. 631. strait, iii. 631. torcular Herophili, iii. 631. lateral sinuses, iii. 632. occipital, iii. 632. petrosal, superior and inferior, iii. 632. transverse, iii. 652. cavernous, iii. 633. circular, iii. 633. pia mater, iii. 633. of the spinal cord, iii. 633. of the brain, iii. 634. continuations of the pia mater into the cerebral ventricles, iii. 634. choroid plexuses of the lateral ventri- cle, iii 634. velum interpositum, iii. 635. 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, iii. 636. arachnoid, iii. 636. spinal, iii. 636. arachnoid bag or sac, iii. 636. sub-arachnoid cavity, iii. 636. internal arachnoid, iii. 637. cerebral, lii. 637. cerebro-spinal fluid, iii. 638. fluid in the cerebral ventricles, iii. 640. oriflce of communication, as described by Majendie, between the fourth ventricle and the sub-arachnoid space, iii. 640. estimate of the quantity of the sub-arach. noid fluid, iii. 64l. cerebro spinal fluid in reference to patho- logy, iii. 642. manner of its secretion, iii. 643. physical and chemical properties of the cerebro-spinal fluid, analyses, iii. 643. use of the cerebro-s})inal fluid, iii. 643. glandulbale, iii 684. pons Varolii, iii. 685. corpora quadrigemina, iii. 68.5. processus cerebelli ad testes, iii. C86. valve of Vieussens, iii. 686, conclusions, iii. 686. cerebellum, iii. 687. arbor vitae, lateral and median, iii. 692. castration, alleged efiects of, on the cere- bellum, iii. 687- commissures, iii. 691. long and hidden, iii. 601. short and exposed, iii. 691. single, iii. 691. corpus dentatum or rhomboideum, iii. 692. crus cerebelli, iii. 692 peduncles of, iii. 69.3. inferior, iii. 693. rnUhllc, iii. 693. superior, processus cerebelli ad testes, or cerebro-cerebdlar 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. laminoe, iii. 689 — 691. lobe^ and lobule.s, iii. 689. amygdala?, iii. 689. 692. biventral, iii. 689. 692. median, iii. 689. posterior, iii. 689. 692. pyramid of Red, iii. 691. uses, iii. 691. posterior superior lobe, iii. 689. 692. slender, iii. 689. spigot of Reil, iii. 691, 692. uses, in. 691. square lobe, in. 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. 690. ventricle, fourth, iii. 693. aqucductus Sylvii, iii. 693. calamus scriptorUis, iii. 693. chor(»id plexuses of the fourth ven- tricle, iii. 693. Nervous Centres, cerebellum —cowif/n/rrf. 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. 693. 695. convolutions, iii. 693. indicat'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, 69.5, primary convolutions in the fox, iii, 696. in the dog, iii. 696. in cats and hyenas, iii. C96. secondary convolutions in ruminants, iii. 696. in the elephant, iii. 696. in the monkey, iii. 696. in the human subject compared witli that of the inferior animals, ill. 696. symmetry, iii. 096. constant convolutions in the hu- man brain, iii. 697. 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, in. 698. disappearance of the convolutions in hydrocephalus, iii. 698. corpora striata, iii. 698, course of fibres, iii. 699. vesicular matter, iii. 699. oi>tic thalami, iii. 700. corpora genicukita, iii. 700. corpora maminillaria, iii. 701. commissures of the brain, iii. 701. longitudinal commissures, iii. 701. 1. superior longitudinal commis- sure, iii. 7oi. 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. 703. 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 ot the microscopic anatomy of the spinal cord and brain, iii. 7(j7* of spinal cord, iii. 707. medulla oblongata, iii. 708. mesocephale, iii. 709. cerebrum and cerebellum, iii. 709. Briefstatement of the probable modus operand! of the brain, iii. 710. Nerves and Nervous Centres (abnormal anatomy), iii. 712. regeneration of nervous matter, iii. 712. abnormal anatomy oftbespinal 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 ol blood, iii. 715. tubercle, iii. 715. cancer, iii. 715. GENERAL INDEX. 825 Nerves and Nervous Cui^TnEs^con/fmied. Abnormal anatomy of the brain and its membranes, iii. 715. 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. 71fi. effusion of blood, iii. 716. arachnoid, iii, 716. acute inflammation, iii. 71^. opaque condition of, iii. 716- causes of opacity, iii. 716. adhesion, iii. 716.. deposits of bone or cartilage, iii. 716. effusions into the subarachnoid and arach- noid cavities, iii. 716. of serum, iii. 716. of blood, iii. 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 hemispjieres, iii. 71H. 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, iir. 72u C. anaemia, iii. 720 C. cerebral h?emorrhage, 720 D. cancer, iii. 720 E. tubercle, iii, 720 E. entozoa, iii. 720 E. morbid states of the ventricles, iii. 720 E. thickened and opaquecondition of the lining membrane, 720 T. 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 covering.^, iii. 720 F, abnormal anatomy of nerves, iii. 720 G. 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 of voluntary nerves, iv. 141. fatty accumulation in the, iv. ps, Nertoos System (physiology of the), iii. 7.20 G. vital endowments of nerves and of nervous centres, iii. 7-20 G. nervous polarity, iii. 720 IT. sensitive and motor, incident and reflex nerves, iii. 720 H. the stimuli of nerves, iii. 720 K. mental stimuli, iii. 720 K. physical stimuli, iii. 720 K. effects of the galvanic stimulu.s, iii. 720 L. of the conditions necessary for the maintenaiice of the power of developing nervous force, iii. 720 0 . nervous influence or energy, i. 722. vis nervosa, Iii. 29. vis in.sitain 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 V iii. 720 Q. conclusions respecting muscular and nervous forces, iii. 720 S. of the functions of nerves, iii. 720 T. of the roots of spinal nerves, iii. 720 U. of the nervous centres, 72J X. of the spinal cord, 420 X. facts in the physiological history of the spinal cord, iii. 720 X. physical nervous actions of the cord, iii. 721 A. Nervous System — continued. sympathetic actions, iii. 721 A. Whyit’s view's, iii. 721 B. summary of Prochaska’s w’ork, 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, sulstances 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 concerned, iii. 721 I. Dr. Marshall Hall’s doctrine regarding, 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 N. antero-lateral columns, iii. 7210. 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- cUo-motory system ef nerves and true spinal cord, iii. 721 U. hypothesis of Muller and others that every nerve-fibre in the body is continued into the brain, iii. 722 B. Todd and Bow’man’s hypothesis that all the nerves are implanted in the grey matter of the segments with whicli 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. mesocephalc, 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, ill. 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. 723 B. corpus callosum, iii. 723 D. fornix, iii. 723 l3. pons Varolii, lii. 723 E. summary of the physiology of the encephalon, 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. abducentes oculi, iii. 707. accessory, i, 731. acoustic. See auditory, acromial, iv. 753. branches, iv. 753. for adductor magnus, iv. 765, anastomotic branches ofaciomial, iv. 751. of ankle, i. 151. of anus, i. 181. arterial, i. 224. articular, iv. 768. auditory, ii. 272, 530. 539; iii. 597. 692. 707. 826 GENERAL INDEX. Nerves in particular — continued. auricular, great, iii. 90S ; iv. 753. superncial branch, iv. 753. deep branch, iv. 753. external, ii. 294. 555. iriternal, ii, 293. 555. l^osterior, 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, j. 436. for brachialis anticus, iv. 756. buccal, ii. 291 ; iii. 950 ; iv. 547. of bulb of penis, iii. 918. calcaneal, superior and inferior, iv. 770. internal, iv. 7T0. cardiac, inferior or small, ii. .595. 851 ; iii. 575 . 687 ; iv, 815 ; s. 42.5. left, ii. 595. middle, ii.595, left, ii. 596. superior, or long, ii.595 ; iii. 722. cardiac branch of vagus, iii. 887. 896. 9U2. of ninth jjair, iii. 722. carotid of glosso-pharyngeal, ii. 496. of Vidian, ii. 288. cerebro-spinal, s. 443. cervical,! 748; ii. 272; iv. 754. descending, iii. 721. internal, iii. 721 ; iv. 753. superior, ii. tl2. 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. 361 ; iv. 436. GOG. 759. clavicular, iv. 753. of clitoris, s. 7(i9. for coclilea, ii. 534. 540. communicans fibula?, iv. 76S. tibialis, iv. 62. iioni, iv. 753. communicating of acromial, iv. 753. to coraco-brachialis, iv. 756. of Cotunnius, ii. 287. of cranium, i. 748, 749. for crura?us, iv. 763. crural anterior, iv. 761. femoral, iv. 762. cutaneous, external, i. 217- 361 ; ii. 64 ; iv. 756. internal, i. 217. 361 ; ii. 64 ; iv. 755. 763. malar, ii. 284. middle, iv. 763. long, ii. 252. of arm, internal, ii. 361. of Wrisberg, iv. 756. ]>a!mar, iv. 757- peroneal, iv. 768. of shoulder, 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. descendens noni, iii. 721 ; iv. 754. of diaphragm, ii. 4 ; iv. 754. digastric, ill. 9(i4 ; iv.547. of glosso-pharyngeal, ii. 496 ; iii. 949. digital, first, iv. 757. secoml, iv. 757. third, iv. 757. fourth, iv. 757. firth, 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, 228, 229. See Fifth Pair of Nerves; Seventh Pair of Cerebral Nerves. facial, ii. 228, 289 540. 544. 554, 555; iii. 707. 919. See Fifth Pair of Nerves; Seventh Pair of Cere- bral Nerves, of Fallopian 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 ; iii. 784. frontal, ii. 279 ; iii. 93. 784. internal, i. 748. Nerves in particular — continued. ganglionic, iii. 547* gastric of vagus, i i. 899. for gemelH muscles, iv. 767. genicular, internal, ii. 241. genito-crural, ii. 833 ; 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. hfemorrlutidal, inferior, iv. 766. hypo-gastric, iii. 9IS. hypo-glossal, iii. 707. 721 ; iv. 1141. ilio-hypogastric, iv. 761. ilio-scrotal, iv. 761 . infra-ciavicular, iv. 755. infra-maxillary, iv. 548. infra-orbital, ii. 284. infra-trochlenr, 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-huineral, iv. 760. interosseous, iv. 757. 768. of musculo-spiral, iv. 759. of Jacobson, ii. 495. 554. of kidney, iv. 2‘36. 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-sacial, iv. 761. of lymphatic glands, iii. 218. malar, ii. 284. branch of optic, iii. 788. cutaneous, ii. 284. malleolar, iv. 769. of inamm«, 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, 291. median, i. 361 ; iv. 756. in arm, i. 217. 361 ; ii. 524. in hand, ii. 527. muscular branches, iv. 756. anterior intero.sseous nerve, iv. 7.56. palmar cutaneous branch, iv. 757. terminal digital branches of the median, iv. 757. of medulla oblongata, iii. 684. to membram tympani secundaria, ii. 549. molles, i. 224. motor linguEe, 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, lii. 595. ninth, iv. 721. 1141. obturator, iv. 761. 764. 766. accessory, iv. 764. deep, iv. 765. long cutaneous, iv. 765. superficial, iv. 764. cesophageal, ii. 3 ; iii. 759. 895. POI. olfactory, iii. 625. 707. 731 ; iv. 698. to omo-byoid, iii. 721, 722. oidUhalmic, ii. 279 ; iii 93; iv. 621. branches, ii. 279 — 282. GENERAL INDEX. 827 Kerv^s in particular — continued. optic, iii. 595, 596. 676. 707. 762. 785, origin and course, iii. 762. orbicular, iv. 5-17. orbitar, i. 749. orbital of superior maxillary, iii. 787. palatine, ii. 286 ; 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 vagum, 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. 917, 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 Vidian, il 288. pharyngeal of glosso-pharyngeal, ii. 496. branch of vagus, iii. 885. 892, 901. phrenic, ii. 3, 4; iv. 754. 815,816. left, iv. 754. right, iv. 754 . plantar, internal, iv. 770. external, iv. 771. branches, iv . 770, 771. pneuinogastric, i. 732; ii. 3.554; iii. 112.572. 692. 707. 759. 949 ; s. 262. popliteal, external, iv. 62. 7G8, 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. 292. pudendal, inferior, iv. 439 ; s. 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 quadratus 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. 887, 888. 895. 901. renal, iv. 236. for rhomboideus, iv. 755. respiratory internal, iv. 754. sacral, iv. 752 765. saphenus, i. 148; ii. 352. accessory, iv. 763. external, or communicans tibiali.s, iii. 130; iv. 770. internal, iii. 130. satellite of femoral artery, iv. 763. sciatic, iv. 459. lesser, iv. 766. greater, iv. 767. for semi*membrano5US, iv. 768. for semi-tendinosus, iv. 767. septual of olfactory, iii. 732. to serratus magnus, iv. 755. seventh pair, iv. 543. sixth pair, iii. 787 ; iv. 621. spermatic, external, iv. 762. 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. 547. for subclaviiis, iv. 755. subcutaneous of the hand, ii. 524. suboccipital, iii. 658. 707; iv. 750. subscapular, inferior, i. 361 ; iv. 755. superior, i. 361. superficial of neck, iii. 571. temporal, i. 749 ; ii. 284. 293. supra-acromial twigs, iv. 571, Nerves in particular — continued. supra-davicular, iv. 753. 755. 818. supra-maxillary, iv. 548. supra-orbicular, iv. 547. supra-orbital, j. 748. of supra-renal capsules, iv. 833. supra-scapular, iv. 434. 755. supra-trocheator, i. 748. supra-trochlear, ii. ^0 ; iii. 93. branches, ii. 280. sympathetic, i, 423; iii. 598, 599. 949 ; iv. 621. 816; s. 262. of Vidian, ii. 288. of taste, iv. 8.^. temporal facial, ii. 283. 555 ; iii. 904. superficial, i. 749; ii. 284. 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, iii. 787. thoracic, i. 361. anterior, or short, i. 361 ; iv. 755. middle, i. 361. posterior, or respiratory, i. 361. of thymus gland, iv. 1094. to thyro hyoid, iii. 722. of thyroid gland, iv. 1107. tibial, anterior, i. 151 ; iii. 132. 134 ; iv. 62. 768, 769. posterior, i. 1.50. 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. 55*4, 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, i. 387. of uterus, s. 641. vaginal, s. 707. vascular branch of vagus, iii. 887. for vastus internus, iv. 703. 1381. vestibular of auditory, ii. 540. Vidian, ii. 287. of Wrisberg, i. 360. AV>w-iubes. See Nerve. AVrac-vesicles, caudate, iii. 647. Nemous tissue, element of the, i. 126. of birds. SeeAvES; I.n'stinct. Neumatoneura, locomotion of the, iii. 534. Neuralgia, ii. 229 ; iii. 720 K. of the urethra, iv. 1263. Neu7‘ile?na, ii. 185. of nerves, iii. 591. wavy course of the nerve-tubes within the, iii. 593. Neurinc, iii. 593. Neuroma, or tumours formed upon nerves, iii. 720 G ; iv. 141. Neui'optcra, 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 equina; in summer, ii. 8o7. Newton, 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. Night-maj'e iv, 688. Night-ynoths (Nocturna), ii. 867- A’^o/ic nations, mental and physical characters of the, iv. 1356. Ninth pair of Nerves, iii. 684. 721 ; iv. 1141. origin and course, iii. 721. branches, iii. 721. of communication with the superior cervical gan- glion, iii. 721. de.'cendens noni, iii. 721. omo“hyoiil branch, iii. 721. plexus, iii. 7‘22. 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 di^trlbation, iii. 722. comparative anatomy, iii. 722. root of the ninth nerve in the ox, iii. 722. in birds, iii. 723. in fishes, iii. 7*23. physiology of llie ninth nerve, iii. 723. Nipples, or mammillae, iii. 246. cuticle, rcte inucosum, and cutis of nipple, iii. 246. 3 II 2 828 GENERAL INDEX, N/ppIes — continued. I'orm and position, iii. 246. alterations iii form during lactation, iii. 246. glands and papillcC, iii. 246. the areola, ii. 247. cliange in colour after impregnation, iii. 247. cuticle and cutis of the areola, iii. 247. tubercles of the areola, iii. 247. i^innldo*. or hirrl-lice, ii. 868. Kisus lonnations of IMumenbach. theory of, iii. 145. l>sitric 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, lii. 81 6. of a hotly containing nitrogen, iii. 817. nitrogen thrown off by decaying bodies, iv, 456. Isitroleucid aciil, iv. 165. j\7//-o-saccharic acid, ii. 40.5. y(ib(itcu.t physical characteristics of the existing descendants of the, iv. 1.366. yochlhorn^ a genus of Quadrumann, iv. 9.\lyCtscq- See OUADRGMANA. characters of the genu?, iv. 211. Noctuj-na^ or night-moths, a section of Insects of the class Lepidoptcra, ii. 867. characters of the section, ii. 867. Nodes described, i. 440. 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, lii. 723. bones, iii. 723. structure of, iii. 726. cartilages, iii. 7-C. structure of, iii 727. muscles, iii, .541-. IT}. pyramidalis, iii. 728. levator labii superioris ala*quo nasi, iii. 728. triangularis, iii. 728. depressor aUe nasi, iii. 72S. depressor septi nanum, iii. 729. muscubir fasciculi which dilate and compress the nostrils, iii. 729. rhomboideus, iii. 729. purjioses served by the muscles of the nose, iii. 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. bulh, iii. 732. branches, iii. 732. sei)tual, iii. 732. labyrinthic, iii. 733. other nerves, iii. 733. See Fifth Pair of Nerves ; Seventh Pair of Nerves. vessels, iii. 733. mucus of the, iii. 481. analy.sis of, iii. 482. chemical characters of, iii. 482. development of the nose, iii. 7.3k physiology of the nose, iii. 735. See also Face; La- rynx; Mucus; S.MF.LL. 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. 73S. thickening of the mucou? membrane, iii. 738. ulceration, iii. 739. polypi, iii. 739. vesicular, iii. liO. gelatinous, iii. 740. fibrous, iii. 740. malignant, iii. 740. enlarged appearance of, in hard drinkers, ii. 228. nasal calculi, iv. 82. Nostrils, iii. 7'/6. cartilages of the, iii. 726. Notch of acetabulum, ii. 776. cotyloid, s. 1 1 6. ligament of the, iv. 434. of palate bone, ii. 211. posterior, or purso-like fissure of the cerebellum, iii. 688. sacral, s. 119. sacro-sciatic, s. 127. sciatic, great, s. 1 1'>. « 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. Noto?nmata, a genus of Rotifera, iv. 404. longiseta, jv. 410. inyrmeleo, iv. 413. Nourisfwient of the young, instincts guiding parents in procuring, iii. 15. Nubinns, mental and physical characters of the, iv. 1356. Nuchti, or nape of the neck, i. 367. I'uruncuU in the, i. 368. ligament of, of Fachydermata, iii. S76. Nnchus, ligament of, i. 732. Nuclc^ canal of, iii. 943 ; s. 706. Nuclei of intestinal calculi, iv. 84. animal, vegetable, and inorganic, iv. 84. Nudn, characters of the family, i. 523. Nudibranchinta, ii. 377. See Gasteropoda. “ Nurse ” and “ grand-nurse ” of Sleenstrup, 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. reduciionof every protein compound to albumen, iii. 742. change from albumen to fibrin, iii. 743. formation of tissue, lii. 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. 751. Jiypcrtrophy, iii. 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. Nijmph form of insects, ii. 879. Nymplue, 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 nymphie, s. 710, O. OaJc trees, injuries to, by the Scolytus pygmaeus, ii. 862. Vat-7nenl, effect of abundant use of, in producing inte.>tinal 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. 7S9« 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. ineirbrane, s. 124. 126. ossification of the, s. 207. vein, iv. 1412. GENERAL INDEX, 82'J Ocearit effect of animal life at the bottom of the ocean on the economy of the world, iv, S8. absolute darkness of the, at the depth of 800 to 1000 feet, hi. 204. Occa«/c nations, mental and physical characteristics of the, iv. 1j6I. variety in the complexion of the, iv. 1334. OcelUi 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. develojiment, 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. 6-9. sulcus, i. 732. 734. tubercle, external, i. 732. vein, iv. 1405, 1406. ventricle, iii. 674. Occipito-Jrontal region, i. 746. See Cranium, regions and muscles of. muscle, i. 732. 747. 749. Occiput^ i. 725. OctopodOf i. 520, divisions of the tribe, i. 521. parasitic nature of the, i. 544, 545. Octopus vulgaris, its mode of creeping on the shore, iii. 446. eyelids of the, iii. 95. Ocular conjunctiva, iii. 83. See Conjunctiva. peduncles of Crustacea, i 758. Oc2//o-cerebral congestion, a cause of myopia, iv. 1464. Ocythoe^ genus ofTestacea, i. 523. Odontoid ligament, i. 732. Odontoliths^ or tartar, of teeth, iv. 83. Odorous emanations, hypotheses of the nature of, iv. 697, 698. (Ecistes, a genus of Rotifera, iv. 402. (Ecistinay a family of Rotifera, iv. 4'JI, et sei, characters of ihe family, iv. 401. genera of, iv. 402. (Edcma^ i. 5l6; iii. 82. 85. (Egoscerida^ a sub-order of Mammalian quadrupeds, s. 5U8. anatomical characters of, s. 508, et seq. (Esophageal arteries, 1. 193; s. 326- branches of nervus vagus, iii. 895. 901. nerves, ii. 3. plexus, left, iii. 889. right, iii. 889. CEsophagds, i. 11 ; iii. 758 ; iv. 816, 817. definition, iii. 758. normal anatomy, iii. 758. dimensions, iii. 758. directions, iii. 7.78. mucous membrane, iii. 759. oesophageal glands, iii. 759. relations, iii. 758. cervical, iii. 758. thoracic, iii. 758. abdominal, iii. 758. structure, iii. 758. vessels and nerves, iii. 759. ce.sophageal blanches of the nervus vagus, iii. 895. motor influence of the sympathetic in refer- ence JO the oesophagus, s. 464. function of the oesophagus, iii. 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. oes»'pliagotomy, iii. 576. oesophagus of fishes, iii. 981. of Uuminantia, s. 535. (Estridee^ or gad-flie.s, ii. 867. (EstruSt li. 127. Offence .QXid defence, instincts designed for the purposes of, iii. 7. Oil, nutritive properties of, ii. 13. Oil-heetles (CaiUharidae), ii. 863. Old age. See Age. Olecranon process, i. 217 ; ii. 63. 66. 162. surfaces, ii. 162. structure, ii. 16>. fractures, ii. 169. Oleophosphoric acid, iii. 587. Olfactory ajiparatus, 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. 597. l»rocess, or lobe, iii. 597 . 698. 722 N. convolutions which enclose the fissure of the, iii 698. 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, psalterlum, m-nnyplies or feuillet (third stomach), of Ruminantia, ii. il ; s. 537. Omentum, i. 51. greater, or gastro-colic, i. 502; iii. 937, 938. 941. s. 309. sac of the, iii 938. layers of, iii. 941. vessels and nerves of, iii. 942. use of, iii. 942. homology of, iii. 942. lesser, iii. 94i. 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. 3U9. phreno-gasiric, s. 309. hernia of, ii. 763. See Hernia. condition of the omentum in cases of umbilical Iiernia, ii. 763. Omichmyle, iv. 1270. O^/20-clavicular space, iv. 817. 0/?m-hyoid muscle, i. 483 ; iii. 105. 563. action and relations, iii. 563. branch of ninth pair of nerves, iii. 721. 0?«;j/m/o-enteritic duct, s. 401. Ow/^/m/o-mescnteric artery, i. 169. Onagga, or Dauw (Equus montanus), the, iv. 714, Ondatra, anatomy of the, iv. 370, el scq. Onyx or hypopion', ii. 203. Opacity and transparency of bodies, iv. 1438. Opalina, digestive organs of, s. 295, Ophidia, an order of Keptilia, iv. 265. 272, ct seq. Ciliary motion in, i. 63l. digestive organs of. s. 3Ul. teeth of, iv. 888- tongue of, iv, 1 147- ’ organs and mode of progression of the, iii. 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. Ophrydinidte (loricated bell animalcules), a family of Poly- gastric animalcules, iv. 4. characters of the family, iv. 4. Ophryocercinidee (swan animalcules), a family of Polygastrlc animals, iv. 5. characters of the family, iv. 5. Ophthalmia, catarrhal, causes of, iiL 86. 94. Egyptian, causes of, iii. 86. Ophthalmic artery, i, 491 ; ii. 179. 186. 227 ; iii. 93. 733.785. branches, i. 491, 492. 730. nerve, ii. 279 ; lii. 93 ; iv. 621. branches, ii. 279 — 282. See Fifih Pair of Nerves. ganglion, ii. 281. pustula, ii. 176. tentacles of Cephalopoda, i. 526. See CEriiALOPOUA. vein, ii. 228 ; iii. 786. cerebral, iii. 94. facial, iii. 94. Opiothrix fragilis, ovum of, s. [126.] OpUtholonos, i. 719. Opium, efiect of large doses of, on the action of the heart, i. 797. its peculiar influence upon the spinal cord, iii. 721 H. Oto? or laserpUiura, iv. 862. Opossums, lii. 261, et scq. habits, peculiarities, &c. of, iU. 261. pelvis of, s. 16l). 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. Ofiponcns 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, 186; iii. 707. 7G2. 785. descriptive anatomy, iii. 762. apparent origin, iii. 762. tractus opticus, iii. 762. chiasma, iii. 762. optic nerve proper, iii. 762. first stage, iii. 762. second stage, iii. 762. communication with other nerves, iii. 763. organisation, iii. 763. real origin, iii. 763. evidence derived from comparative anatomy, iii. 76-t. Fish, iii. 7Gi- Keptilos, iii. 764. Birds, iii. 761. in Man the optic nerves derive some roots from ilie tubercula quadrigemina, iii. 765. the tubeicula quadrigemina probably fulfil other purposes besides that of affording origin to the optic nerves, iii. 766. tile human optic nerve probably derives roots from the optic thalamus, lii. 766. corpora geiiiculata: their relation to the optic nerves, iii. 763. tuber ciiiereum: its relation to the optic nerves, iii. 768. commissure of, in, 595. 676 ; iv. 1446. peripheral expansion of the, iii. 596. of the chirisma of the optic nerves, iii. 768. in Invertebrata, Osseous Fifh, iii. 769. Cartilaginous Fish, iii. 769. Bird.s, ill. 7f9. Amphibia and Reptiles, iii. 769, Mammalia and Man, iii. 769. use of the chiasma, iii. 771 . some remarkable varieties ol optic nerves, iii. 774. optic nerves in certain Ceplialopods, iii. 774. optic nerves of the compound eyes of Insects, iii. 775. plaited optic nerves, iii. 776. optic nerves in cyclops monsters, iii. 777- general developmetic of the optic nerves in the higher classes of animal'j, iii. IT.. Fish, ill. 777. Birds, iii 777. Mammalia, iii. 777. functions of the optic nerves, iii. 778. tiie optic nerves when present are essential to vision, iii. 778. in tiiose animals which possess special optic nerves the tilth fiair are totally inadequate to support vision, iii. 778. absence of proof that 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, Ui. 782. Optic pore of optic nerve, iii. 186. 192. thalami, iii. 675. 700. corpus geniculatum externum, iii. 700. internum, iii. 7UU. fibres, iii. 700. commis.'^ures, 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 Optical principles governing the construction of micro- scopes, iii. 331. See Microscope. OptoU/n/ surfaces, iv. I44U. Optometer of Dr. I'orterfield, i v. 1141. Orbicular, or annular, ligament, iv. 229. nerves, iv. 547. Orbicularis palpel^rarum muscle, iii. 80, 81. 211. 221. tendon of tlie, iti. 81. action, ii. 221. relations, ii. 221. uses of the, iii. 82. See also Face. or sphincter oris muscle, ii. 223. relatioiv^, ii. 223. actions, ii. 224. Crt)iculus s. circulus ciliarls, — 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. '?83. lachrymal gland, iii. 784. fourth nerve, iii. 784. frontal nerve, iii. 784. lachrymal nerve, iii. 784. muscles, iii. 784. levator palpebras 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. oplithalmic 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 palpebree, iii. 788. recii, iii. 788. obliqui, iii. 789. consensual movements of the two eyes, iii. 791. adaptation of the eye to distances, iii. 792. See also Vision. Oibital foramina, i. 730, 731. nerve, i. 749 ; iii. 787. process, i. 73U, 731 ; li. 211. or external, surface of lachrymal hone, 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, 2U8. borders, ii. 208. Or5/Yo-palpebral muscle, ii. 222. Orchis morio, mode of origin and early development of the cmliryo in, s. 250. Orchitis, iv. 1UU4. acute, iv. lo04. chronic, iv. 1006. syphilitic, iv. 1008. Organic Analysis, iii. 792. 1. Pro.ximate 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. 796. quaiititative;;^analysis, iii. 796. process, iii. 796. sjiecial 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. 800. oxalic acid. ivi. 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. 803. iodine, fluorine, and sulphur, iii, 803. bases, iii. 803. potash, soda, ammonia, iii. 804. iron, lime, magnesia, lead, iii. 804. copper, iii. 805. GENERAL INDEX, 831 Organic Analysis, Proximate — c(mtmued. B. Analysis of animal solids, lii. 803. cholesterin, iii. 805. uric acid and urates, iii. 805. cystic oxyde, iii. 805. albumen and fibrin, iii. 805. gelatinous tissues, iii. 806. hairs, iii. 806. earthy phosphates, iii. 806. carbonate of lime, iii. 806. o.xalate of lime, iii. 806. C. Analysis of individual secretions, iii. S07. 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, iii. 811. 4. of bile, iii. 8l I. 5. of saliva, iii. 812. II. Ultimate analysis, iii. 813. analysis of a solid not containing nitrogen, iii. 814. 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, iii. 819. Organic life, i. 263. Orgnmc matter, considered, iii. 152. presumed impossibility of artificially producing 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 compounds probably due to their want of acquaintance with the form or condition in which their cumpoiients must be brought together, in order to enter into tlie 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. Orga7iisation and stimulus, conditions required for the pro- duction of vital actions, iii. 142. vital properties due to the act of organisation, iii. 142. connexion of organisation with vitality, iii. 148. See Life. bodies compared with unorganised, i. 118. See Ani.mal. Ornithorhynchus paradoxus, the, iii- 367, ct seq, description of the animal, iii. 367. 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. Orthopfera, an order of Insecta, ii. 8G4. characters of the order, ii. 854. nervous system of the, iii. 610. Orycteropus^ or Cape Ant-eater, teeth of the, iv. 870. 0)-yctei-us, white-spotted (Bathiergus capensis), iv. 389. Oryctes nasicornis, nervous system of, iii. 610. Oscula of sponges, iv. 67. Ossa maxillaria superiora, ii. 207. palatina, ii. 210. spongiosa, v. turbinata infima, ii, 212. triquetra, triangularia, suturarum, supranumeraria, 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. “ Oiscoi/s juice,” ancient theory of, in theadhesion of bones, i. 444, 445. Osseous labyrinth, ii. 533. liquid contained in the, ii. 536. membrane lining the, ii. 533. Osseous system, i. 438. See also Bone. diseases of the, i. 4 ^9. in early life — growth, i. 438, nativity, i. 438. old age, i. 439. Osseous System (comparative anatomy), iii. 820. general remarks, iii. 822. enumeration of tiie parts of a perfect vertebrate endo- skeleton, iii. 823. skeleton of the Crocodile, iii. 823. spinal column, iii. 8i'3. elements of a vertebra, iii. 824. autogenous parts, iii. 824. exogenous parts, iiu 824. Osseous System — continued* skull, iii. 825. occipital vertebra, iii. 827. parietal vertebra, iii. 827. frontal vertebra, iii. 827. bones of the cranium, iii. 828. frontals, iii. 828. anterior frontals, posterior frontals, iii. 829. parietals, iii 829. external occipitals, lateral occipitals, inferior occipital or basilar, iii. 829. sphenoid, alars, iii, 829. squamo-teinporal, petro-temporal, iii. 829. ingrassial bones, iii. 829. ethmoid, vomer, nasal bones, iii. 830. inferior turbinated, iii. 830. maxillary, intermaxillary, iii. 830. suborbital, pr^nasal, supra-temporal. iii. 831. palatine bones, transverse bones, internal pterygoid, zygomatic, masto-teinporal, iii. 832. styloid, symplectic, iii. 833. lower jaw, iii. 833. opercular, angular, articular, iii. 833. hyo-branchial apparatus, iii. 833. hyoid, iii. 833. branchiostegous rays, iii. 834. branchial arches, id. 834. pharyngeal bones, iii. 834. condition of the os hyokles in Reptiles, iii. 835. metamorphosis of the os hyoides, iii. 835. thorax, iii. 8c6. vertebral ribs, iii. 836. sternum, iii. 837. sternal ribs, iii. 833 limbs, id. 839. anterior, iii. 839. scapula, iii. 839. clavicle, iii. coracoid, iii. 840. humerus, id. 840. fore-arm, iii. 840. carpus, iii. 840 metacarpus, iii. S41. phalanges, iii. 84i. posterior, iii. 842. ilium, ill. 842. ischium, iii. 842. pubis, iii. 842. marsupial bones, iii. 84?. femur, iii. 843. tibia, iii. 843. 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. 845. supra-temporal, iii. 845. bones of the azygos fins of Fish, iii. 845. OssEOi.’s Tissue,!. 127; iii. 847. general description, 847 hyalitic substance, iii. 847. lamina, iii. 849. Haversian canals, iii. 849. corpuscles or cells, iii. 850. growth of bone, iii. 853. madder experiments, id. 853. development of os.'^eous tissue, iii. 854. ossification of permanent cartilage, iii. 857. abnormal osseous plates in the suit tissues, 857. formation of osseous tissues in the union of fractures, iii. 857. Ossicles or small bones of the ear, d. 546. See Hearing, Organ of. office of the, in the functions of hearing, ii. 573. 377. 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 gall-bladder, iii. 183. 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, id. 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 cssifying tumour, iv. 135. OsteoJna, or abnormal ossification, iv. 134. in the natural tissues, iv. l.Li. healing of fractured cartilage, iv. 134. osteophytes, iv. 134. osteoma, iv. 135. osteoid, or ossifying fungous tumour, iv. 135. bone formation in the interior of new products, iv. 135. Osteomalacia, iv. 97., 3 H 4 832 GENERAL INDEX, OstcophijtcSy iv. 134, 135. Oat^opfcri/^Uy a division of Fishes, ill. 95o. characters of the division, iii. 956. Osteosarcoma^ osteosteatoma, spinaventosa, enchondroma, i. 460; iv. 132—1.34. description of, i. 460. loralitics attacked, i. 460. ])rogress of, i. 462, symptoms, i. 462 of tile hones of the face, ii. 220. malignant, of the hand, ii. 516. benign, of llie hand, ii. 514 — .516. remarkable case of, ii .515. Oo7co-s.ircomatous tumours of tlie i>elvis, s. 206. Ostcum sinus, ii. 538. internum aqueductus vestibuli, ii. .530. sive apertura, scalae vesUhuli cochloie, ii. 530, tubuli, ii. 538. Ostium abdominale, s. 599, 600. uterinum, s. 599. vei ti. See Anus. Osirca (oyster), nervous system of the, iii. 604. Ostrich, pelvis of the, s. 1^. velocity of the, iii. 451. Otic, or auricular, ganglion of Arnold, ii. 292. 555. Sec SvMPAi'iiETic Nerve Otitis of ihc membraiKi tymiiani, ii. 575. Oto Indian, pf»rtrait of, iv. 1368. Otoconia, ii. 539. See IIeaiung, Organ ok — membraneous labyrint h. oftiee ot the, in (he function of hearing, ii. 567. Oto^lcna, a genus of Rotifera, iv. 404. Otulicnii , a genus of Quadrumana, iv. 214, et scq. See Quadhumana. characters of the genus, iv. 214. Oioliihi, ii. 539. Sec Hearing, Organ of — membraneous labyrinth . office of tlie, in the function of liearing, ii. 567. of fishes, iii. 1004. Otter, feet and mode of progression of the, in water, iii. 430. Ourang-cctan (Simla satyrus), anatomy of tlic, iv. 198, ct scq. organs and mode of progression of the, iii. 455. pancreas of the, s. 98. organs of voice of the, iv. 1487. Ova snbvcntanea, ii.455. Oval fenestra, or fenestra vestibuli, ii. 530. for.imen ofspfienoid, ii.53U. pelvis of car, ii. 530 Ovariitn arteries, s. 552. 640. cllusions, analjsis of, iii. 483. veins, iv. 1 413. Ovaritis, or inflammation of the ovary, s. 576. Ovary, s. 547. normal anatomy, s. 52. 547. form, s. 547- dimensions and weight, s. 49. 547. position and connexions, s. 548. component parts, s. 548. ]. protecting parts or tunics, s. 548. jjeiitoneum, tunica albuginea, iii. 944; s. 56. 548. 2. ]iarenrliyma or stroma, s. 549. .3. Graafian vesicles, ii. 449; s. 56, 550. 4, bloodvessels and nerves, s. 552. relation of the ovaries, ovum, oviduct, and uterus in Mammalia, s. 53. 51. relations of the form of the ovaries to thedischarge of ova, s. 54. structure ot the ovaries themsedves, as related to the production of the ovula, s. 56. functions of the ovary, s. 552. apjiroximation of the timbriated extremities of the Fallopian tuiies to the ovary after iruitful sexual union, ii. 447. vascularity of, during and after sexual union, ii. 447, 418. influence of the, in developing the general sexual peculiarities of the female, ii. 714, ct scq. the developmental changes in the ovicap.^ules, and the process of emis.vion of ova, s. 5:>2. 1st stage, origin of the ovicapsules, s. 5.54. 2nd stage, growth, maturation, and prepara- tion for dehiscence, s. 555. Sid stage, rupture or dehiscence, and escape of ova, s. 558. 4th stage, decline and obliteration of the ovi- capsules. s. 561. A. without impregnation, s. 561. li. after impregnation, s. 663. spontaneity of the emission of ova, .s. 566. n.iture of the corpus luteum, ii. 419 ; s. 5b4. .56 \ da^si^^ed arrangement of all the condition^ whicli the Giaafiaii follicle exhibits during evolution and involution, s. 570- summary of the cone usions which the e conditions afford with reference to questions in obstetric and forensic medicine, s. 571. development ami involution of the ovary, s. 571- the origin of the ovary, and the alterations which U imdcrg'ies at difteicnt periods of life, s. 571. Ovary — continued* abnormal anatomy of the ovary, s 573. cdlects 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 ofthe proper tissues, s. 576. hypersemia, 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 cf cysts, 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 ofthe solid contents ofeysts, s. 586. fa^tus contained in the ovary (?) ; the question of ovarian gestation considered, s. 586. examples of supposed ovarian gestation, s. .587. origin of ovarian cysts in general, s. 590. solid enlargements, of the ovary, s. 5;U. cartilaginous and ossific formations, s. 591. cancer, colloid or alveolar, medullary and scirrhous, s. 591. scrofulous tubercles, s. 593. Ovicnpsule. See Graiifinn follicle. Oviduct, s. 597. See I'alloyian tube. Oviposition in Arachnidans, i. 211. See Araciinidans; Ovum. Ovis, anatomical characters of, s. 508, ct scq. Ovis Aminou, vocal organs and voice of, iv. 1494. Ovisac, structure of the, s. 551. (Jvo~viv/pa7‘ous animals, i 146. generation, ii. 424. 407. 434. See Generation; Ge- neration, Organs ok. Ovology. See Ovum. Ovulatijn, s. 3. See Ovum. Ovuium, or unimpregnaled ovum, ii. 4.51. Ovum (in animal anatomy and physiology), s. 1. See also Generation, definition, s. I, review of the topics to be discussed, s. 1 . sexual and noii-scxual modes of reproduction, s. 2. I. of tiie 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 emhryo-cell, s. 4. development, or embryo-genesis, s. 4. structural distinctive characters of an ovum, ii. 4-34. 448. 451 ; s. 5. II. ofthe non-sexual mode of generation, s. 5. 1. of the process of reproduction in Protozoa, or aniTTials in which tlie sexual distinction has not yet been discovered, s. 6. Gregarina?, s. 7- 2. of the possibility of primary, direct, or non-pa- rental production of animals, or of so- called sjiontancous 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. 1 3. alternate reproduction of — Echinodennata, s. 14. Polypina, s. 16. Acaleplue, s. 20. Moilusca, s- 22. Salpida?, s. 23. Entozoa, s. 24. cystic Entozoa, s. 25. free tapeworms, s. 27. Trematnda, s. 29. Annelida, s. 32. Insecta: Aphides, s. 33. general remarks on alternate generations, s. 13. 34. tlie “ nurse ” of Steenstrup, s. 37. parthenogenesis, s. 37. additional remarks, 4fk Ovum * of GENERAL INDEX. 833 — continued. the ovum previous to the commencement of foetal development, s. 43. anatomical structure, chemical composition, origin, and formation of tlie ovum in man and animals, £ 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, s. 53. in oviparous Scaly Beptiles, 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. b. 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 t\iajirst groiq)^ s 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 ; ovu.ura 3 yolk and its contents, s. 68. microscopic structure of the ovum, s. 71. yellow or external yolk substance, s. 71. substance of the cavity and canal, s. 72. cicairicula, 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 small granular yolk and complete seg- mentatioujS. 80. ovum of Mammalia and of the human species, s. [81]. uniformity in size, &c., s. [8IJ. Graafian follicles, s. [8IJ. tunica or membrana granulosa, s. [82]. external tunic, or zona pellucida, s. [82]. 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]. manner in which tlie ova of Mammalia may be procured, s. [88 J. origin and formation of the mammiferous ovum, s. [89]. formation of the ovules, s. [89]. origin of the Graafian follicles, s. [89]. formation of the cumulus, s. [90]. similarity of the structure of tlie ovum throughout the families of the class Mammalia, s. [90]. except in the Monotremata, s. [90]. ova of the Ornithurhynclius, s. [91]. ova of Echidna hystrix, s. [91]. third group of the ova of Vertebrate Animals, s. [91]. Amphibia — Batrachia, s. [91]. structure of the ripe ovarian ovum in Amphibia, s. [91] embryonic develojnncnt, s, [93]. yolk substance, s. [93]. germinal vesicle, s. [93]. vitelline membrane, s. [94]. formation of the ovum and changes in its progress, s. [94]. Ovum, Vertebrate Animals — continued. Osseous Fishes, s. [98]. structure of ovarian ovum, s. [ 8]. yolk-substance, s. [99]. germinal vesicle s, [99]. membranes, s. [*-9]. micropyle, s. [101]— [103]. development, s. [I03j, [IW]. Invertebrate Animals, s. [104]. laige-yoked ova with partial cleavage, s. [105]. Cephalopoda, s. [105]. Gasteropoda, s. [106] Acephald, s. [108].' Arthropoda, s. [110]. Insecta, s. [ 1 lOJ. Arachnida, s. f 114], Crustacea, s. [115.'. Annulata, s. [117]. Rotifera, s. [118], Turbellaria, s. [119]. Entozoa, .s. [120.] Nematoidea, s, [120] Trematoda, s. [i24j.‘ Cestoidea, s. [124]. Echinodermata, s. [125]. Polypina, s. [126J. Acalephae, s. [129]. Protozoa, s. [129], 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 lacts 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. [136J. 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. 669. functions of Fallopian tube, reception and transmission of ova by the Fallopian tube, s. 6U5. 5. relation of the ovum to fecundation by the male sperm, s. [156]. 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 unfecuii- dafed 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. [141 J. ichthidine, s. [141]. ' ichthuhne, 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- molahotryoidesjor 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. Oiols, eyelids of, iii. 97. Ojt, anatomical characters of the, s. 508, et scq. cranium of, s. 5U9. 513. muscles of the, s. 524, 52.5. effect of castration on the growtli of the horns, 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. S06. deposit of, in urine in disease, iv. 1283. Oxalic acid. iii. 80O. method of determining the presence of, iii. 800. syncope from, i. 797- Oxides in animals ami vegetables, i. 125. 83i GENERAL INDEX. Oxygen, respiration of, in animals, i. 133. 257, 258. quantity of, abstracted from tlie atraospliere by respi- ration, iv. 326, 327. 354. ^veight of oxygen gas in the atmosphere upon every part of the earth’s surface, iv. 327. Oxytrichinid.ee (hackle animalcules), a family of Polygastric animals, iv. 5. characters of the family, iv. 5. Oxyuri, ii. 113. Oysters^ nervous system of, iii. 60f. See Concuikeua. OXiCnat iii. 739. P. Paca (Cavia Paca), anatomy of the, iv. 372, el scq. Pacchionian bodies, iii. 629. 631. 691. description of them, iii. 644. are they natural structures ? iii. 645. gland', i. 729. 735^ iii, 629. 631. 64-1. 645. fossae, i. 729. 735. PACiiYDEa.MATA, ail Order of Mammalia, iii. 858. enumeration of genera, iii. 859. osseous system, lii. 859. cranium, iii. 859. occipital hone, iii. 8.59. parietal bones, iii. 860. frontal bones, iii. 860. ethmoid, iii. 8i)0. sphenoid, iii. 861. ribs and sternum, in. 861. anterior extremities, iii. 862. scapula, ill. 862. clavicle, iii. 8()2. humerus, iii. 862. radius and ulna, iii. 362. carpus, iii. 863. metacarpus, iii- 163. phalanges, iii. 863. posterior exiremilies, iii. 864. pelvis, iii. 864. lemur, iii. 8ii4. tarsus, ui. 864. metatarsus, iii. 864. phalanges, iii. 864. teeth, iii. 865. of Suldie, iii. 865. Choiropotainidae, iii. 865. Hippopotamidee, iii. 866. Toxodon, Elasmotlienum, iii. 806. IlhinocerutidtE, iii. 866. iJinotherium, iii. 867. Proboscidia, Elephant, ui. 867. digestive system, lii. 871 ; s. 303. stomach and inteatine.s, liver, iii. 871, 872. spleen, lii. 871. salivary glands, iii. 872. os hyoides, in. 872. circulatory and respiratory system, iii. 872. thymus gland, iv. 1097. urinary organs, iii. 873. generative organs, in. 873. male, iii. 873. female, iii. 873. pelvis, s. 155. Weberian organ of, iv. 1419. nervous system, iii. 874. brain, iii. 874. special senses, iii. 874. touch, iii. 874. Biiout, iii. 874. proboscis of the eltphant, iii. 875. smell, iii. 875. frontal, maxillary, and sphenoidal si- nuses, ill. 875-6. eye, iii. 876. ligamentum nucha5, iii. 876. organs and mode ol locomotion, iii. 454. Pacinian I^odies, lii. 876 ; s. 504. general description, iii. 876. stalk, iii. 878. channel for the stalk, iii. 878. capsules, lii. 878. ariery, iii. 878. central cavity, iii. 878. nerve tube, iii. 879. function, or use, ni. 879. comparison with the electrical organs of the torpedo, iii. 879. anatomy of the, iv. 376, cf SC7. Paf^urus (liermit-crab;, nervous system of the, iii. 613. Paieotherium, anatomy of the. 8ee Pachvdekmata. palate, liard, iii. 950. See Palatine arch, soft, lii. 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. inferior, ii. 211. interior, ii. 210. superior, ii. 211. Palate — continued. connexions, ii. 21 1, development, ii. 21 1. 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 amygdala?, 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. 72o. canal, anterior, ii. 203. glands, iv. 426. hiatus, i 727- holes, accessory, ii. 210. nerves, ii.286; iii. 951. great, ii. 286. lesser, ii. 286. miildle palatine, ii. 286. posterior palatine, ii. 287. process, or plate, ii. 208. 210. veins, iv. 1404. Po/«/o-glossus muscle, iii. 952 ; iv. 1121. 1152. relations and action, iii. 952 ; iv. 1133. 7^n/«/o-pharyngeus muscle, ii. 947- 952 ; iv. 1121. relations and action, iii. 952. Pa//7^o-staphylinus muscle, iii. 952. palm-cats, dentition of the, iv. 91 1. 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. Palmcllece, mode of reproduction of the, s. 220. 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* fa.scia, 227- fissure, or rima palpebrarum, iii. 79. ligaments, exiernal, iii. SI. 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. Pancueas, 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. 83, upper border, s. 82. lower border, s. 83. anterior suiface, s. 83. posterior surface, s. 83. size and weight, s. 83. general appearance, s. 84. internal structure, s. 84. duct of the pancreas, s. 8 k vessels, s. 86. arteries, s. 86. lymphatic vessels, iii, 226; s. 86. nerves, s. 86. II. Microscopic anatomy, s. 86. gland substance, s. 86. oc.. the basement or limitary membrane, s. 87. (B. epithelium, s. 88^ y. occasional appearance of a central cavity in eacii follicle, the epithel um lining it in a single coluinnal-looking layer, and leaving a central space unoccupied, s. 89. duct, s. 89. capillaries, s. 90. III. Comparative anatomy, s. 90. Invertebrata, s. 90. Gasteroi>oda, s. 90. Cephalopoda, s. 90. Vertebrata— Fishes, iii. 982; s. 91. pyloric appendages, s. 91. Reptiha, s. 94. Batrachia, s. 94. Ophidia, s. 95. Sauria, s. 95. Chelonia, s. 95. GENERAL INDEX 835 Pancreas, Comparative Anatomy — continued. Aves, i* 327 j s. 96. table of pancreatic ducts in several orders of Birds, s. 97. Mammalia, s. 98. of Marsupialia, iii. 305. of Rodentia, iv. 390. in Ruminantia, s. 541. of the horse, iv. 732. IV. Physiology, s. 99. opinions of old authors, s. 99, et scq, results of analyses of the pancreatic secretion, s. 102. function of the pancreatic fluid, s. 105. V* Morbid anatomy, s. 108. a. quantitatively perverted nutrition, s. 108. hypertrophy, s. 108. atrophy, s. 108. induration, s. 109. softening, s. ’09. b. inflammation, s. 109. c. haemorrhage, s. 110. d. structural changes, s. 110. 1. non-malignant ; cartilaginous transforma- tion, s. 110. steatomatous concretions, s. 110. cystic tumours j hydatids, s. 110. fatty degeneration, s. 111. 2. malignant, s. 111. scirrhus and carcinoma, s. 111. fungo-h$matoid disease, i. 112. €, calculous concretions in the pancreatic duct, s. 112. occurrence of fatty stools in connexion with pan- creatic disease, iv. 95 ; s. 112. See also Glaxo. Pancreas Asellii, i. 479. See Carmvora. Panci'eatic arteries, L 195 ; s. 8d. calculi, iv. 86. juice, i. 127. share taken by the pancreatic juice in the process . of digestion, s. 39^ vein, iv. 1414. Pancrfa^fco-duodenalis artery,!. 194 j s. 86.326. vein, s. 381. Pandora (Acalepb$), i. 38. Panniculus curnosus of the Porcupine, Hedgehog, &c. iii. 544. Panorpa communis, or common scorpion- fly, ii. 864. Panoiyina, or scorpion flies, a section of Insects of the order Neuroptera, ii. 864. characters of the section, ii. 864. Papilla: of various parts of the body, iv. 1165. vascular and nervoussupply to thepapillce, iv. 1165. of cervix uteri, s. 639. lachrymales, iii. 80. 91. of nipples, iii. 246. of the tongue, iv. 1136. circurnvallate, iv. 860. 1122. 1136. fungiform, iv. 860. 1137. conical or flliforra, iv. 860. 1138. simple, iv. 860. 1139. structure of, iv. 1139. functions of, iv. 1140. morbid conditions of, iv. 1159. hypertrophy of circurnvallate and fungiform papilla, 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. 1161. healing and reparation of the papilla, iv. 1161. Papillary body of palpebral conjunctiva, iii. 85. Par Vagum Nerve, iii. 881. origin, course in the cranium, iii. 882. ganglion superius, iii. 882. communicating filament with the glosso-pharyn- geal, iii. 882. auricular branch, iii. 883. passage of the vagus along the neck, iii. 884. 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, iii. 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. 891. Par Vagum Nerve, physiology — continued. sensitive filaments, iii. 892. functions of the various branches, iii. 892. auricular branch, iii. 892. j)haryngeal branches, iii. 892. laryngeal branches, iii. 893. effects of the laryngeal nerves on phona- tion, iii. 895, CBSopliageal branches, iii. 895. cardiac branches, lii. 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 motifeious filaments? in. 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 ga^tric juice, iii, 900. upon tile 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. Paraceyiiesis abdominis, operation of, i. 6. 9. recto-vesical, iii. 923. vesica 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 hypersemia 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. 4U2, 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. ParaphrenitiSy ii. 6. Paraplegia, iii. 37. 40. state of the urine in cases of, iv. 407. Parusitesy human, ii. 111—137. See Entozoa. animal. See EiXroZOA, vegetable, iv. 143. Parasitical animals in the blood, i. 429. in the cellular tissue, i. 516. acephalocy»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, CO. Parenchymay 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. 229. Paronychia 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. 902 ; iv. 423. position, iv. 423. relations, iii. 902. form and dimensions, iv. 423. duct of the parotid gland, or duct of Steno, iv. 423. 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 Region (in surgical anatomy), iii. 902. parotid gland, iii. 902. relations, iii. 902. arteries, iii. 903. external carotid, iii. 903. internal maxillary, iii. 903. transversahs faciei, iii. 903. posterior auricular, iii. bU>. 83G GENERAL INDEX. Parotid Region — continued. veins, iii. 903- temporal and inlernal maxillary, iii. 903. ])Osterior auricular, iii. 903. transverse facial, iii. 903. exteiual jugular, iii. 903. nerves, iii. 903. great auricular, iii. 903. branches, iii. 903. auiicular, superficial, iii. 903. dee)), iii. 903. auriculo. temporal, iii. 903. superficial temporal, iii. 19. auricular branch, iii. 903. porlio 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. sirucuire ami ilevelopment, s. 593. abnormal states, s. 597. Parrot, its inoile of clinibmg and apparatus for prehension, iii. 4^)1. cyclitls of, iii. 97. vocal organs and voice of the, iv. 1500. Parrot-Jishe&, dental apparatus of, iii. 979. teeth 01 the, iv. 871. 878. Parthcno^s.enesis, s. 37. pAUTURmoN, Meciiani.sm of, iii. 904. in the lower animals, iii. 904. attitude and position of the fadus, 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 poNition, iii. 90^. jiresentation of the lower extremities, iii. 908. cross presentation, iii. 908. mechanism of the pelvis in parturition, s. 146. changes in tlie uterus after parturition, s. 658. process of involution of tlie gravid uterus, s. 653. changes in dimensions and weight, s. 658. met.imorphosis and restoration of the component ti'sncs. s. 659. office of the uterus in parturition, s. 672. general sketch of the labour process, s. 672, 673. ]»eristaltic action of the uterus and its cause, s. 673. rhythmic action of tlie uterus and its cause, s. 674. influence of the difierent nervous centres upon the uterus in pir u it. on, s. 675. the exciting cause of labour, s. 677. part taken by the abdominal muscles in promoting, i.l7. immediate agent of expulsion in, iii. 721 L. influence of the obliquely contracted jiclris upon par- turition, s. 2('2. pathological condition of the uterus after jiarturition, s. 7u2. irregular contraction; hour-glas.s contraction (ar- rested peri.staltic action), s. 702. incom))lcte and retarded involution, s. 702. puerperal inflammations, s. 702. emio-metritis, s. 702 mctro-jililebitis, s. 703. inetro-pentoiiitis, s. 703. blooil-dycrases, s. 704. Passcrcs, jiclvis of the, s. 169. “ Pastern, great,” of the horse, iv, 719. PatcLa, or Knee-pan, ii. 168. de^ elopment, ii. 168. loiin ami position, ii. 163. structure, ii. 168. ligaments of, i. 251 ; iii. 45, 46. surfaces, li. 168. compared with that of the lower Mammalia, ii. 1C8. fracluies, iii. 69. (li>l()i utions, iii. 73. rupture of ligament of patella, iii. 78. Patella vulgaris (limpet), nervous system of the, i. 113; iii. 605. Pathelici nerves, ii. 370; iii. 707. distribution, ii. 370- function, ii. 370, 571. origin and cranial course, ii. 370. See also Orbit, Musi les of hie. Paunch, or pause, of Uumiiiantia. ii. 11 ; .s 535. PavUion, or infundibulum, of Fallopian tube, s. 601. Pearls, formation of, i. 713. Pecan', stomach of the, s. 30 k Pecten, or marsupium nigrum in Aves, ii. 203. Pecten i.or scallop), nervous sysrein of the, iii. 604. Pectines of scorpions. See Scorfdons. Pectinibi anchiata, ii. 378. See UAbi'EROPODA, Pcctincus muscle, s. 137. nerves to. iv. 763. pectoral extremities of Marsupialin, iii. 280, Pcctornlis major muscle, i. 217. 359. minor, i. 359; iv. 573. Pedate larva? of insects, mode of locomotion of, iii. 441, Pediastrum, mode of reproduction of the, s. 2j3. Pedicellina Felgica, a species of Polypifera, iv. 59. mode of reproduction of, iv. 59, GO. ova of, s. 23. development of true ova of, s. 23. [1273- PedicuVidce, ii. 868. Pcdunculi, or crura, cerebri, iii. 678, 679. of crus cerebelli, iii, 693. interior, iii. 693. middle, iii. G93. superior, — processus cerebelli ad testes, or cerebro- cerebellar commissures, iii. 693. of the pineal gland (haben®), 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, 236. Pelonaia, a genus of Tunicata, iv. 1193. et seq. Pelouaiudcc, a family of Tun.cata, iv. 1193, ct scq> cliaracters of the family, iv. 1193. Peloic fascia, ii. 231 ; iii. 933. Pelvis, s. 114. definition, s. 114. innominate bone, s. 114. its office, s. 1 14. 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. 116. descending ramus of the pubis, s. 116. obturator or tbjroid foramen, s. 116. sub-pubic or obturator groove, s. 116. - internal or |>elvic surface, s. 117. iliac tuberosity, s. 117. sacral or auricular surface, s. 117* internal iliac fossa, s. 117. ilio-pectincal hue, s. 117- internal structure of the innominate bone, s. 117. sacrum, s. 1 18. its office, s. 118. base, s. 1 18. apex, s. 118. anterior or pelvic surface, s. 118. Iiosterior surface, s. 1 18. lateral surfaces, s. 119. internal structure of the sacrum, s. 119. coccyx, s. 12U. development of the pelvis, s. 120. innominate bone, s. 120. sacrum, s. 120. coccyx, s. 121 . pelvic articulations and ligaments, s. 121. lumbo-pelvic articulations, s. 121. proper or intra-pelvic articulations, s. 121. sacro-coccygeal joint, s. 122. motions of the joint, s. 122. sacro-ihac 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-ihac ligaments, s. 123. the deep and supeificial layers of fi- bres, s. 123. ilio lumbar ligament, s. 124. great sacro-sciatic ligamci.t (ligamentum pelvis posticum magnus), s. 124. lesser or internal sacro-sciatic ligament (ligamentum pelvis posticum parvuin), 8. 124. movements of the sacro-ihac 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 apjiearance of the articulated pelvis, s. 126. its interior aspect, .s. 126. lateral aspects, s. 126. jjostei ior 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. 138. inferior aperture of the male [lelvis, iii. 919. position and shape of the, iii. 919. axes of the male pelvis at d.Hcrent 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. l.^O. inclination of the pelvis, s. ISl. angles of the anterior and posterior pelvic walls with the transverse vertical plane, s. 133. ilio-ischial angle, s. 134. angle of ischio-pubic arch, s. 134. axes of the pelvis, s. 134. axis of the brim, s. 135. of the inferior outlet, s. 135. general development of the pelvis, s. 135. the pelvis of infants, s. 136. in advanced adult age, s. 137. muscular attachments of the jrelvis, s. 137.’ 1. muscles acting on the trunk and spine, s. 137. posterior spinal group, s. 137. abdominal group, s. 137. 2. muscles acting on the leg, s. 137. flexor group, s. 137. extensor group, s. 137. adductor group, s. 137. abduclor group, s. 137. rotator group, s. 137. 3. muscle^ acting on the perineum and genitals, s. 138. posterior perineal group, s. 138. anterior perineal group, s. 138. fascial attachments, s. 138. lumbar fascia, s.^138. abdominal fasciee, s. 138. crural fascia or fa-=cia lata, 8. 138. pelvic fascia, s. 138. perineal fascia, s. 138. crura of the penis or of the tliforis, s. 138. mechanics of the human pelvis, s. 138. in regard to parttirition, s. 146. comparative anatomy of the pelvis, s. 148. pelvis of Negro, s. 14S, 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. 130. 3. the square or four-sided form, s. 150. 4. the cuneiform or oblong form, s. 150. pelves of the Simia?, s. 151. of the Carnivora, s. 154. of the Phocas, s. 155. of the Pachydermata, s. 155. Runiinantia, s. 157. Rodentia, s. 158. Marsupialia, iii. 282; s. 159. IVIonotrcmata. s. 161. Edentata, s. 161 . insectivora, s. 161. Cetacea, s. 165. Birds, s 165. Reptiles, s. 170. Fishes, s. 172. table of comy)arative pelvic angles, s. 174. 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, AD^^oR.MAL .Anatomy of the, s. 178. pelvic deformities and obstructions, iv, 945; s. 178. 1. Normal irregularities, s. 178. equable deviations, s. 178. pelvis jpquabiliter justo major, s. 178. pelvis «quabiliter justo minor, s. 178. cause, s. 179. irregularities from imperfect development — infantine pelvis, s, 179. masculine pelvis, s. ISO. irregularities of the pelvi-vertebral angle, s. J81. 2. Distortions, s. 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. 182. inward projection of the sciatic spines, s. 182. distortions affecting the outlet only or pr inci- pally, s. 183. contraction of the transverse diameter, s. 183. special cause of this deformity, s. 183. contraction of the antero-posterior dia- meter, s, 183. distortions affecting the whole pelvis, s. 18.5. ovate, elliptical, orreniform pelvis, s. 185. ilia and ischia, s. 18.5. symphysis pubis, s 185. Pelvis, ovate, elliy tical, or reniform — continued. Uiameter, s. 185. sacro-vertebral angle, .s. 185. inclination of the superior plcne, s. 185. cordiform or angular pelvis, s. 187. sacral promontory, s 187. ilia and ischia, s. 187. pubic symphysis, s. 187. angles of the superior and inferior pubic planes, s. 187.^ diameters, s. 187. causes of the foregoing pelvic distortions, s. 189. rickets, s. 189. m'dlities ossium or malacosteon aduUo- rum, s. 190. mechanism of the preceding pelvic distortions, s. 195. influence of the centre of gravity of the trunk, s. 195. the line of pressure, s. 196. influence of continued posture, s. 196. lying upon the back, s. 196. lying upon the side s. 197., tendency of the sitting posture, s. 197. degree of obstruction, s. 199. the pelvis oblique ovata, or obliquely con- tracted pelvis, s. 200. cause of the obliquely deformed pelvis, s. 203. mechanism of this deformity, s. 204. obstructions caused by osteo-sarcoma- tous tumours, s. 206. obstruct'ons from fibrous tumours at- tached to the pelvic ligaments, s. 206. effects of carcinomatous growth, s. 206. pathology of the pelvic joints, s. 206. ankylosis, s 207. coalescence of the bones composing the sacro- lumbar articulat ons, s. 207. ossification of the sacro-iliac joint, s. 207. ossification of the sacro sciatic ligaments, s. 207. separation of the bones at their articular surface.^, s. 207. ether congenital abnormalities, s. 208. siren formation of pelvis, s. 208. influence of hip-joint disease upon the pelvis, s. 208. fractures and dislocations'of the pelvic bones, s. 208. fracture of the sacrum, s. 208. coccyx, 209. innominate bone, s. 209. dislocation of the sacro-iliac or pubic joints, s. 209. disjilacement, s. 2(i9. diagno.'is, s. 210. Pelvis of kidney, iv. 238. epithelium of pelvis of kidney, iv. 254, ovalis of ear, ii. 530. Pemphigus of the feetus in utero, ii. 333. Penis, lii. 909. definition, iii. 909. comparat've anatomy, iii. 909. in Infusoria and Botifera, iii. 909. in Entozoa, iii. 909. in Annelida, iii. 90'\ in Cirrhopoda, iii. 909. in Crustacea, iii. 909. in Insecta, iii. 910. in Mollusca, iii. 910. in Veitebrata. iii. 910. Fishes, iii. 910. Amphibia, iii. 910. Ophidia, iii. 910. Sauria, iii. 910. Chelonia, iii. 910. Aves, iii. 911. Mammalia, ii. 423 ; iii. 91 1. Quadrumana, iii. 911. in Man, iii. yil. ii'tegument, iii. 911. prepuce, iii. 910. rra?niim prseputii, iii. 910, subcutaneous areolar tissue, iii. 912. fascia penis, iii. 912. corpus caverno'um, iii. 912. structure, ii. 14.5. 423. 445 ; iii. 9i2. trabeculje, iii. 912. septum pcc tiniforme, iii. 913. vasco-cellular structure, iii. 913. contraciile fibrous ti.'^sue, iii. 913. corpus spongiosum and glaus penis, ii, 423, 424. 445 i 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 peni.s, iii. 915. acceleratores uvina?, iii. 915. jschio bulbosus, iii. 915. compressor vente dorsalis penis, iii. 916. 838 GENERAL INDEX. Penis in Man — continued. arteries, ii. 146; iii. 916. arteria 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 ven® corporis cavernosi, iii. 917. dorsal vein, i. 388 ; iii. 917. ultimate arrangement of the blood-vessels, iii. 917. arteria? helicina?, iii. 917. lymphatic ve.^^scls, iii. 918. nerves, iii. 918 ; iv. 766. development, iii. 9IS. local changes con.«;equent on puberty, ii. 439. mode of union of the arteries with the veins, ii. 446. bone of penis in some animals, ii. 446. urethra. See UiiETim,\. causes of erection, ii.445, 446. influence of the spinal cord on the, iii. 721 B,721 E, 721 T. conddion 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. VenicilUum verticillatum, organs of reproduction of, s. 224, Pennntula grisea, a species of Polypifera, iv. 38. pliosphorescence of, iv. 38. PennatuUdcpy a family of Polypifera, iv. 20. 38. characters of the family, iv. 20. genera, iv. 2(), Penniform rug® of uterus, 8. 629. 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. 395. Peranieles (or bandicoots), a genus of Marsupialia, iii. 260, ct seq. characters of the genus, iii. 260. Perdti climbing, conformation of the, iii. 986. Perching birds ( Insessores), characters of, i. 267. Percidee^ a family of Fishes, iii. 956, et seq. characters and genera of the family, iii, 956. Perfornns Casscrii nerve, i. 561. 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 fadiis in utero, ii. 334. Pericardhun, ii. 597, .698 ; iv. 522, .523. uses of the pericardium, ii. 598. ve.ssels within the pericardium, relative position of the, ii. 598. affections of the pericardium in the fo?tus in utero, ii. 334. congenital absence of the pericardium, ii. 633. hydrops pericardii, ii. 645. ossification 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 PIeart. Perichondrinmy i. 248. Pericranium, i. 748, 749. Peridina’adcc (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. Perineal artery, superior, s. 713. superficial, iii. 928. trans\er-^e, iii. 929. hernia, iii. 932. muscle, transverse, iii. 920. nerve, external, iii. 938; iv. 439. 766; s. 714. internal, iv. 439. cutaneous, iv. 767. fascia, s. 138. deep, s. 138. superficial, s. 138. Perineum (in surgical anatomy), Hi. 919, bony and ligamentous boundaries, iii. 919. axes of the pelvis at different ages, iii. 919. rectum, iii. 920. course, &c. iii. 920. relations, iii 921. coats, iii. 921. bladder, vesicul® seminales, and vasa deferentia, iii. 922. urethra, iii. 923. prostatic portion, iii. 924. ineinbranous portion, iii 925. hulband spongy portion, iii. 925. Perineum — continued. dissection, iii. 926. superficial compartment, iii. 926. integument, iii. 926. superficial fascia, iii. 927. central tendinous point of the perineum, iii. 928. superficial perineal artery and veins, iii. 928. inferior or sujierficial division of the pudic nerve, iii. 928. transversalis perinei artery, iii. 929. accelerator urina? 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. 932. 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. ])assage of the testicle into ihe perineum, iv. 988. fissure of the, a cause of spurious liermaphroditism, 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 omnium, i. 749. Peristalsis, or transverse constriction of the stomach, s. 313. Perisfaphylivus externus muscle, iii. 951. Peritoneal covering of ovary, s. 548. inflammation of, s .574. or serous, lamin® 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. 935. relations of the diaphragm to the peritoneum, ii. 4. continuity of the peritoneum traced, iii. 936. omenta, mesenteries, and ligaments, iii. 940. 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. 942. homology of, iii. 942. transverse mesocolon, iii. 942. mesentery, iii. 943. ascending and descending mesocolon, &c., iii. 943. appendices epiploic®, iii. 943. recto- vesical folds, iii. 943. broad ligaments of the uterus, iii. 943. recto-uterine and vesico-uterine folds, iii. 943. other slight folds and de])ressions, 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. 945. minute anatomy. See Serous Membrane. softening of the peritoneum, iv. 708. malformation, i. 508. Peritonitis, iii. 945. abnormal adhesions and other results of peritonitis, iii. 94.5. effects of. on the action of the heart, i. 797. Peritreyna of the stigmata of Arachnidans, i. 204, 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: peron®al cutaneous, iv. 768. peron®al saph®ruis, iv. 768. suj)erior external articular, iv. 76^, inferior external articular, iv, 768* brevis muscle, i, 152; iii. 131. 138. action and relations, iii, 138. GENERAL INDEX, 839 Peroneus — continued. longus muscle, ii. 355. 357 » iii. 131. 138. action and relations, iii. 138. tendon of, i, H9. 152. tertius muscle, ii. 352 ; iii. 131. 137. relations, iii. 137. action, iii. 138. tendon of, i. H9. Pcrophora. a genus of Tunicata, iv. 1188. characters of the genus, iv. 1188. Persistence of the urachus, i. 393- Perspiration or sweat, sensible, i. 127 ; ii. 1-19. constituents of, ii. 149. quantity excreted in twenty-four hours, ii. 149. See also Sweat. PerUy evidences of the high degree of civilisation attained by the ancient inhabitants of, iv. 13d0. Pes anserinus, i. 485; iii. 581. equinus, anatomical characters of, ii, 349. PetaiiristSy or Flying Opossums, iii. 263. PelauruSy a genus of Marsupialia, iii. 263, ei seq. characters of the genus, iii. 263. species of the, iii 264. Pelaurus flaviventer, iii. 264. pigmaeus, iii. 264- taguanoides, iii. 224. PetechicCy causes of, i. 422. Petity canal of, ii. 193. Petro-occipital suture, i. 737. Petro-sphenuidnl suture, i. 737. Petroiny~on marinus (or lamprey), iii. 976. teeth and parasitic habits of, iii. 976. respiratory app.aratus of, iii. 976. organs of generation of, iii. 1U06. Petrosal sinus, inferior, or basilar, sinus, i. 752 ; iv. 1406. sulcus, i. 733. nerve, superficial, ii. 554; iv. 545. small petrosal, iv. 54G. minor Arnoidi 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. patches, s. 356. Follicles y intestinal; Stomach AND Intestine. in the intestine of the giraffe, s. 539. glands, iv. 839. Pezizts, rejnocluctive system of, s. 227- PhacochceruSy or wart-hogs of Africa, iv. 870. teeth of the, iv. 870. See Pachvdermata. Phagedcenic ulcers cf the tongue, iv. 1157. Phalangeal ]o\nXSy motions of the, ii. 345. PhalangeVy 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, ii. 342. of fingers, ii. 507- 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 CiUiditions, ii. 511. Phalangisla. a genus of Marsupialia, iii. 262, et seq. characters of the genus, iii. 262. species of, iii. 262, 263. Phalangista Cookii, iii. 262, et seq. Phallusia intestinalis, nervous system of the, iii. 603. Phanerogamia, vegetative system of the, s. 246. Fhanerogamia Gymnospermia, s. 246 Angiospormia, s. 248. Hippuris vulgaris, s. 249. Orchis morio, s. 250. the anther and the pollen-cell, s. 251. review of the analogies which present themselves in the history of tlie development of the reproduc- tive organs of the higher Cryptogamia and of the Fhanerogamia, s. 232. 1. analogies existing between the ovule, the anther, and the sporangium, s. 252. 2. analogy between the embryo-sac, pollen-ccll, and parent cell of four spores, s. 2.72. origin and development of germ-cells in special organs destined for their reception, which are capable of transformation into rtidiments of new plants, without the concurrence of two organs of opposite functions, s. 253. Pharyngeal artery, inferior, or ascending, i. 487; ii. 556; iii 949. proper pharyngeal branch, i. 4S7. posterior meningeal, i. 487. origin and course, iii. 949. superior pharyngeal, or ptcrygo-palatine, artery, i.490. nerve, ii 288. branches of glosso-pharyngeal nerve, ii. 496. branch of vagus nerve, superior, iii. 885. 892. 901. inferior, iii. 885. 893. 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. 887. muscles, iii. 105. plexus of nerves, li. 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. 948. 5. vessels and nerves, iii. 949. See also Par Vagum ; Glosso-pharyngeal Nerve; Spinal Accessory Nerve. mouth, iii. 949. lips, iii. 949. cheeks, iii. 950. palatine arch and gums, iii, 950. gums, iii. 951. velum palati. iii. 9.71. muscles of, id, 951. circumflexus palati, iii. 951. levator palati, iii. 952. palato-pharyngeus, iii. 952. palato-glossus, iii. 952. azygos uvulae, iii. 952. glands of the soft palate, iii. 952. tonsils, or amy'gdalse, iii. 952. course of the mucous membrane, iii. 953. functions, iii. 945. 953. morbid anatomy cf the pharynx and mouth, id. 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. polypi, iii. 954. pouching of the mucous membrane, iii. 954. cancrum oris, iii. 954. calculi of. iv. 83. congenital malformation of the, id. 760. P^rr?7/;), i. 36. Physometrn, s 097, 698. huinida, s. 698. putrida, s. 698. Phytophaga, a tribe of Insects of the order Coleoptcra, i. 561 ; ii. 862. characters of the sub-tribe, i. 563; ii. 862. Phytoxoa. See Polypifera, Pill mater, iii. 633. of the spinal cord. Hi. 633. of the brain, iii. 034. continuations of the pia mater into the cerebral ven- tr.cles, iii. 634. choroid plexuses of the lateral ventricles, choroid plexuses of the fourth ventricle, i crystalline formations in the chore uses, &ia mater, iii. 636. ill refertMire to pathology, iii. 636. abnormal anatomy of the cranial pia mater, iii. 717. injected st.ite of the vessels, iii. 717. tubercle, iii. 7 17. abnormal anatomy of the spinal pia mater, iii. 713. congestion of the venous sinu-es, iii. 713. causes of spinal apoplexy, iii. 713. inflammation of the pia mater, iii. 713. “ Piching of the bcd-clothes ” a sign of approaching death, i. 80n. PicromeU Callenstoff, i. 375. pig, stomach of the, s. 303. urine of the, iv. 1280. See PAcnvDERMAr\ ; scrofa. Pigeon (Columba), nervous system of the, iii. 622. migrating pigeons of America, iii. 18. Pigeon-breast, iv. 1039. pigment in the grey nervous matter, iii. 649. granules of the skin, iii. 496. inclanic, iv. 116. See Products, Adventitioiis. Pigpnentnm r^igrum, ii. 180. chemical composition of, ii. 181, uses, ii. 181. Pilimiction, 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. Hi. 676. anterior, iii. 676. posterior, iii, 676. Pill-hox hydatid, ii. 117. See Entozoa. Piloholus, mode of development and reproduction of, s. 218. Pihdaria. development of, s. 245. Pineal gland, i. 72 ; iii. 676, 677. accrvnlus of the, iii. 677. peduncles or haben$, iii. 677. Pinguedo, i. 57. Phinal cartilages, iii. 726. Pinnipedia, VVeberian organ in, iv. 1418. Pinus Austriaea, development of, s. 247. maritima, development of, s. 247. sylvestris, development of, s. 247. Pipe-fishes, iii. 986. 1010, 1011. Pisces, i. 114 ; iii. 955. general characters, iii. 955. classiflcation, iii. .056. osseous system, iii. 957. skeleton of Osseous Fishes, i. 438 ; iii. 958* vertebral column, iii. 958. 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 vortical fins, iii. 962. skeleton of Chondropterygii, 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 Brancliiostoma, iii. 967. cartilages of the articulations, i. 249. pelvis of fishes, s. 172. Sec also Osseous Fishes, arthroidal system, iii. 967. muscular system, Hi, 968. great lateral muscles, iii. 968. superior and inferior slender muscles, iii. 908. muscles of the pectoral fins, iii. 968. of the ventral fins. iii. 968, of the jaws, iii. 968. of the pahito-tympanic arch, iii. 968. of the operculum, iii. 969. of the os hyoides, iii. 969. of the branchiostegous membrane. Hi. 939. branchial and pharyngeal apparatus, iii. 969* peculiarities of the muscular system in particular fishes, iii, 969. in Ostracions, Hi. 969. in Raida?, iii. 969. muscles of the jaws in Cartilaginous Fishes, Hi. 070. in Sharks, iii. 971 . in Petromyzonidie, iii. 971. tegumenfary system, iii. 971. the skin in general, iii. 971. ]iigmcnt, iii, 972. mucous foll’cles, 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, coil, and mackarel, iii. 437. flat fishes, iii. 437. analysis of the act of swimming in fi.shes, 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. 3C0. oesophagus, s, 300. stomach, s. 300. intestine, s. 300. appendices pyloricie, s. 300. teeth, iii 975 ; iv. 873. in Cyclostomatous Fishes, iii. 976. position, form, mode of implantation, anddeA'e- lopment, iii. 977 ; iv. 873. 880. examples of peculiar dentition, iii 978. Cyprinida?, 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. cesophagus, 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 OvSseous Fishes, iii, 985. in Lophobranchii, iii. 986. in Sturionidte, iii. 986. in Plagiostome Cartilaginous Fishes, iii. 986. in Cyclostomata, iii. 987. in Branch iostoma, iii. 988, hyoid apparatus, iii. 988. branchial cavity, iii. 988. circulatory system, i. 646 ; iii, 988. heart, iii- 988. bulbus arteriosus and branchial arteiy, iii. 989. vascular system, iii. 989. branchial and systemic arterial vessels, iii. 989. systemic veins, iii. 990. organs of respiration of fishes, s. 281 286. air-bladder, s. 281. formation and uses of, iii. 436. mucous membrane and vascular system of, s. 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. Osseous Fishes, ciiiasma of the optic nerves 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 Branchiostoma, iii. 998, senses, iii. 998. smell, iii. 998; iv. 699. eye, iii. 999. sclerotic coat, iii. 999. membrana 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 ofthe eyeball, iii. 1001. eyelids, iii. 95. 1U02. auditory apparatus, ii. 536; iii. 1002. in Petromyzon, iii. 1002. in Osseous Fishes, iii. 1003. membranous vestibule, iii. 1003. sac of the otolilhe, iii. 1003. otolithes, iii. 1004. semicircular canals, iii. 1004. auditory nerves, iii, 1005. ear of Plagiostome Cartilaginous Fishes, iii. 1005. generative system, ii. 418 ; iii. 1005; s. 55. in Cyclostomata, iii. 1006. in Osseous Fishes, iii. 1006, in Plagiostome Cartilaginous Fishes, iii. 1007. male, iii. 1007. female, iii, 1008. in Syngnathidze, iii. 1010. ova of Osseous Fishes, s. [98]. structure of the ovarian ova, s. [98]. yolk substance, s. [99]. germinal vesicle, s. [99]. membranes, s. [99], micropyle, s. [101]— [103]. development, s. [I03J, [l04]. Sapp. Pisces — continued. external forms of ova of Cartilaginous Fishes, s. 51. spermatozoa in fishes, iv. 483. urinary apparatus, iii. 1011. renal capsules, iii. 1011. animal heat of fishes, ii. 649. periodical migration, iii. 13. the migration of the cod, mackarel, thunny, her- ring, salmon, &c., iii. 13. luminousness of fishes, iii. 198. dormant vitality of, iii. 157. Piscicoltti ovum of, s. 117. Pisiform bone. ii. 505. articulations of the, ii. 508. Pitch of the human voice, iv. 1475. 1485. Piiheciciy a genus of Quadrumana, iv, 211 seq. See Qua- DRUMANA. characters of the genus, iv. 211. Pituitary body, iii. 70S. colour, iii. 7('3. earthy concretions, iii, 703. position and connexions, iii. 703. size and weight, iii. 703. structure, iii. 703. fossa, i. 726. membrane, iii. 730; iv. 698. or anterior, surface of nasal bone, ii. 212. process, iii. 673. 703. Placenta^ ii. 424; s. 7i5, 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. terminations of the fcetal vessels, s. 718. decidua, s. 718. terminations of the maternal vessels, s. 719. development of the }ilacenta, ii. 455 ; s. 719. of the foetal portion, s. 719. of the maternal portion, s, 720. functions of the placenta, s. 721. congenital abnormal conditions, iv. 946. separation of the placenta into lobes or cotyledons, iv. 946. Plagiostomay a family of Fishes, iii. 956, ct scq. characters of the family, iii. 956. Plague, syncope induced by, i. 797. Planaria^ a genus of Entozoa of Muller, ii. 116. See Entozoa ; Stcrelmlntha. lactea, a species of parasite, ii. 128. 130. Planari<£, a genus of parasites, ii. 128. 133. ovum of, s. [119]. Planes of the ischia, s. 127. Flanta pedis, or sole of the foot, ii. 339. See Foot. Plantar arch, ii. 355. artery, external, ii. 355. internal, ii. 355. fascia, ii. 354. ligament of tarsus, ii. 343. muscle, iii. 132, 133. 139. action, iii. 139. nerve for the, iv. 62. 769. nerve, internal, iv. 770. branches, iv. 770, 7/1. external, iv. 771. branches, iv. 771. region of the toot, ii. 353. sensibility of the integuments of, ii. 354. muscles of the, ii. 358. veins, ii. 355. deep, external, iv. 1411. internal, iv. 1411. Plants, respiration of, iv. 328. cellular, type of the process of nutrition in, iii. 742. sleep of, iv. 678. sleep of leaves, iv. 678. of flowers, iv. 678. symmetry of, iv. 852. table of the analogies in the development of the different classes of plants, s. 255. Plastinin, dense, ofthe turtle, uses ofthe, iii. 450. sternal, of Crustacea, i. 757. Platypus anatiiius, or Ornithorhynchus p.iradoxu?, which see. See .VIOXOTREMATA. Platysma myoides muscle, i. 483 : ii. 226. 851, 852 ; iii. 565. action and relations, iii. .566. Plcctognathi, an order of Fishes, iii. 957. characters of the order, iii. 957. Plethora, causes and effects of, i. 416. jieriodical in women. See Menstruation. Pleura, iv, 1. 522, 523. 816. mediastinum, iv. 1. ligamentum latum pulmonis, iv. 2. pleura pulmonalis, iv. 2. 1035 ; t. 258. costalis, iv. 2. 1035. dia]diragmatica, iv. 2. parictalis, s. 258. 3 r 84-2 GENERAL INDEX. Pleur \ — continued. relations of the diaphragm to the pleura, ii. 4. softening of the pleura, iv. 7o8. Plcuritis, characters of the urine in. iv. 1291, eases of, in the fcctus in utero, ii. S32. PleuronccteSy a family of Fishes, in. 957. PleuYOtrocha^ a genus of Kotifera. iv. 404. Plexus, lobular biliary, iii. 168, 1G9. 498. 502 ; iv. 451. Plexuses of nerves, iii. 595. Plexus and Plexuses of nerves in jiarticular : — abdominal, of sympathetic, s. 428. aortic, iv. 982; s. 429. 603. inferior, .s. 552. axillary, ii. 361 ; iv. 754. brachial, i. 368 ; iv. 435. 754. 818. cardiac, s. 427- carotid, internal, s. 426. external, s. 426. cavernous, s. 426. cervical, i. 3G8. 748 ; ii. 555 ; iii. 571. deep, iv. 752. posterior, iv. 751, 752. choroid, iv. 525. of brain, iii. 675. of the fourth ventricle, iii. GDI. of the lateral cerebral ventricles, iii. 634. abnormal conditions of tlic, iii. 720 F. coeliac, solar, or ejiigastric, s. 428. coronary, of heart, left, ii, 596. right, ii. 596. superior, s. 429. dia))hragmatic, left, s, 428. right, s. 428. e])igastric, cadiac, or solar, s. 428. gnnglilormis nervi vagi, iii. 884. gula}, iii. 759. hsemorrhoidal, s. 430. Iiepatic, iii. 174; iv. 1414; s. 429. hypogastric, iii. 918 ; iv. 982; s. 4-9. G03. inferior, s. 429. lumbar, i. 10. lumbo-abdominal, iv. 761. mesenteric, superior, iv. 982; s. 429. inferior, s. 429. of ninth pair, iii. 722. o'sophageal plexus, left, iii. 889. right, iii. 889. pharyngeal, ii. 497 ; iii- 949. renal’, iv. 982; s. 429. 552. sacral, iv. 439. 7G5. solar, ccelinc, nr epigastric, s 428. spermatic, iv. 982; s 429. splenic, s. 429. sympathetic, s. 426. of thoracic aorta, s. 428. uterine, s. 430. vesical, s. 430. Plexuses of veins, iv. 1387. 1412. 2’lcxus and Plexuses of veins in particular . — cardiac, great, ii. 596, dii>loic, iv. 1388. liacmorrhoidal, s. 581. intra-spinal, posterior, iv. 1410. lobular, iii. 168; iv. 1414. piiaryngeal venous, iii. 949. prosiatic, iv. 1254. transverse, iv. 1410. uterine, iv. 1412. vaginal, iii. 167 ; iv. 1412. vesico-prostatic, iii. 933; iv. 1412. Plica jjolonica, iv. 144, semilunaris, iii. 80. 84. in comparative anatomy, iii. 84. Plir(V of uterus, s. 629. I'loughshnre bone, or vomer, i. 726; ii. 213 ; iii. 725. Plnrality of urinary bladders in one person, i. 390. paradox us, mode of reproduction of, s. 15. Pjicamatuyucler, construction and mode of operation of the, iii. 31 — 33. l^ncumatosP^ s. tympanites uteri, s. 698. Pneu7)i()(icrma, a genus of Pteropoda, iv. 180. anatomy of, iv. 180. Pneumogaslric nerve, ii. 3. 554; iii. 707.759.881.949; s. 262. See Par vagum. branches of, to the larynx, iii. 112. in foramen jugulare or lacerum, i. 732. flocks or lobules of the, iii. 692. Pneumunia, s. 293. acute, case or, iii. 120. jjcrcussion signs of pneumo-thorax in cases of pneu- monia, iv. 145. characters of the urine in, iv. 1291. Pneumopericardium, ii. 645. Podex. See Anus. Pudophi/rn, or radiated foot animalcule, iv. 13. Pocplioga, a tribe of IVlarsupialia, iii. 265, cl scq. Points, lachrymal, iii. 80. 91. l^oiseuillc's hasmadynamometer, i. 662. his experiments on the force of the blood in the arteries, i. (jf)2. Poison faiigs of serj*eiits, iv. 290. Sb7. glands of serpents, iv. 888. Poisons, action of certain, on the heart, i. 723. s\ ncope by, i. 797. Polarity, nervous, iii. 720 H. Polyarthra, a genus of Rotifera, iv. 404. Polyclinina, a tribe of Tunicata, iv. 1189, et scq, ’ characters of the tribe, iv. 1189. genera, iv. 1189, 1190. Polyclinum, a genus of Tunicata, iv. 1189, ei scq, characters of the genus, iv. 1189. Polydesmidee, a tamily of Myriapoda, iii. 546, ct scq. Polydesmus, a genus of Myriapoda, iii. 546, ei scq. PoLYGASTRiA, a class of iTiicroscopic animalcules, i. 108 ; iii. GUI ; iv. 2. their division into families by Ehrenberg, iv. 3. locomotion of animalcules, iv. 5. nutritive system, ii. 28; iv. 14: s, 295. cilia in animalcules, i. 607. dental system, iv. 15, muscular system, iv. 15. nervous svstem and organs of sense, iii. 601; iv. 16. secretions, iv. 16. reproduction, ii. 408; iv. 16; g. 6. tissiparous generation, iv, 16. gemmiparous reproduction, iv. 17. sporiferous reproduction, iv. 17. Polynesian races, physical and mental characters of the, iv. ite. Polypi organs of circulation in, i. 654. ‘of the digestive canal, s. 419. in the heart and larger vessels, i. 420. concretions in the heart, ii. 648. of tlie nose, iii. 739. vesicular, iii. 740. gelatinous, iii. 740. flbrous, iii. 740. malignant, iii. 740. of the pliarynx, iii. 954. of the rectum, i. 187. of uterus, s. 689—693. -like tumours of the tongue, iv. 1157. PoLYPiFEBA, a class of Zoophytes, i. 1U8 ; iv. 18. division of, into sub-classes and families, iv. 19. organs of digestion of, s, 296. nervous and muscular tissues not discernible, iii. 533. nervous system of the, iii. 601. structure of the integuments of, s. 484. IlydrcG described, iv. 20. extensors of the tentacula, iv, 22. Alcyonid$ described, iv. 24. nutrition of the Alcyonidaj, iv. 27. Corallidas, or cortical polypes, iv. 30. Corallium rubrum, iv. 31. Isis hippuris, iv. 32. MadreporiUae, Madrephyllidae, iv. S3. Fungiae, iv. 33. Pennatulidas, iv. 38. Actiniada*, iv. 38. Aulozoa, iv. 40. Xubularida?, iv. 40. tentacular apparatus, iv. 41. digestive system, iv. 41. circulation, iv. 42. reproduction, iv. 42. mode of propagation, iv. 42. 1. by continuous gemmation, iv. 42. 2. by free geinm®, iv. 43. 3. by simple ova, iv. 46. 4. by ova with a multiple vitellus, iv. 46. 5. by free gemmation and ova com- bined, iv, 47. Tubiporida?, iv. 47. mode of propagation, iv. 47, 48. Sertularida?, iv. 48. Bryozoa, iv. 50. muscular system, iv. 52. alimentary system, iv. 54. reproduction, iv. .55. by gemmae, iv. 55. by ova, iv. 59. development by ova, iv. 60. Polyphyllia, a genus of Folypifera, iv. 36. Polypina, mode of reproduction of the, s. 16. ‘ova of, s. [126J. See also PolypiI’Era. Polysarcia adiposa, i. 6J. Polyspore of red Algae, or Floridae, s. 221. Polystoma pinguicola, an entozoon of the human body, description of the, ii. 121. venaruin, an entozoon of the liuman body, ii. 121. Polystomum integeirimum, a trcinatode parasitic worm, ii. 130. PolyxenidcB, a family of Myriapod®, iii. 546, et scq. characters of the family, iii. 546. Pulyxenus, a genus of Myriapoda, iii. 546. laguius, iii. 546. Pomeridiana, a section of Insects of the class Lcpidoptcra, ii. 867. characters of the section, ii. 867- Pumum Adami, i. 7U; iii. 1U2. 112.573. physiognomical character of, iii, 573. GENERAL INDEX. 843 liopatis, iii. 161. Tariiii, iii. 673. 676. 703. Varolii, i. 732 ^ ii. 270. 272, 273; iii. 673. 678. 685. oftice of the pons Varolii, iii. 723 E. Popliteal aneurism, i. 236. See Aneurism ; Artery. artery, ii. 243 ; iii. 48. branches to knee-joint, iii. 48. Popliteal nerve, iv. 768, internal, iv. 62. external, iv. 62. vein, i. 242 ; iii. 128 ; iv. 1411. origin and course, iv. 1411, 1412. Popliteal Region and Popliteal Autery, iv. 60. definition, iv. 60. muscles, iv. 61. nerves, iv, 62. popliteal artery, iv. 62. varieties, iv. 63. branches, iv. 64. operative relations, iv. 64. PopUtcus muscle, iii. 139. ; iv. 62. relations and action, iii. 139. nerve for the, iv. 769. Porcupiney common (Hystrix cristata), anatomy of the, iv. 372, et seq. quill, of the structure of the, s. 478. 498. Porcupine-rat of Azara (Echimys), anatomy of the, iv. 372, et seq . PoRiFERA, or Amorphozoa (Sponges), i. 108; iv. 64. definition, iv. 64. division into families, iv. 65. skeleton, iv. 66. gelatinous cortex, iv. 67. irritability, iv. 67. circulation of water, iv. 67. liypotheses, iv, 68. reproduction, iv. 69 ; s. 6. gemmules, iv. 70. ova of, s. [129]. non-existence of muscles in the, iii. 532. nervous system of the, iii. 6(/l. organs of locomotion in, i. 40. Porpitay mode of locomotion of the, iii. 433. Porri^o favosa, iv. J44. Portal canals, iv. 1414. Portal vein, iii. 167 ; iv. 250. 1414 ; s. 381. veins which form the portal, iv. 1414. inferior mesenteric, iv. 1414. splenic, iv. 1414. superior mesenteric, iv. 1414. trunk of portal vein, iv. 1414. hepatic veins, iv. 1414. anastomosis of portal and caval veins, iii. 176. vaginal branches and vaginal plexus, iii. 167. interlobular veins, iii. 167. lobular veins, iii. 168. abdominal and hepatic origins of the portal vein, iii. 168. formation of the portal vein in the various Vertebrate classes, iii. 176. anastomoses of the portal and caval veins, iii. 176. 178. nerves of, iv. 1382. dura, or facial nerve, i. 748, 749; iii. 93. 572.707. 9U3 ; iv. 544. posterior auricular branch, iii. 904. digastric branch, iii. 904. stylo-hyoid branches, iii. 904. media, or intermedia, of the seventh pair of nerves, iv. 545. 548. mollis or auditory nerve_, iii. 707. Portuguese, man-of-war, i. 35. 45. See Acalepidf.. Porus opticus, ii. 186. 192. Pol ish, action of, on protein, iv. 164, 165. and on fibrin, iv. 164. PotatOy composition of the, s. 394. considered as the staple aliment, s. 394. and as mixed with other kinds of food, s. 394. ravages of the wire-worm on the potato crops, ii. 861, note Potoroos, or Hypsiprymnus, a genus of Marsupialia, iii. 265, et seq. characters of the genus, iii. 265, 266. Pouchy recto-vesical, s. 369. Pouches of monkeys, iv. 208» uses of, iv. 208, Poupart's ligament, i. 3*. 5; ii. 235, 236. 757 ; s. 137. Prawn, mode of progression of the, iii. 436. Praying insects (Mantida?), ii. 86k Pregnanepy position of the uterus at the end of, s. 648. usual cessation of menstruation during, ii. 440. duration of, constancy of, throughout all the races of mankind, iv. 1341. enlargement of abdominal veins attendant on preg- nancy, i. 15. pregnancy, a predisposing cause of fragility of the bones, i. 441. urine of pregnant women, characters of, iv. 1294. Prehension of food, s, 397. the tongue as an organ of, iv. 1151. PrepucCy pra'putium, iiu 910. Prepuce — continued. fr$num pra:putii, iii. 910. monk’s. head prepuce, iv. 1256, preputial calculi, iv. 82. Preputium clitoridis, s. 709. FreshyopiayX. 80; iv. 1451. 1465. causes, iv. 1465. treatment, iv. 1466. presbyopic spectacles, iv. 1466, 1467. Presentation of the feetus in parturition, iii. 907* of the head, iii. 907. first position, iii. 907. second position, iii. 907. of the face, iii. 908. first position, iii. 908. second position, iii. 908. of the lower extremities — nates presentations, iii, 908. cross presentation, iii. 908. causes, iii. 908. Pre-vertebral fascia of tlie neck, iii. 569. Primitive vein, right, ii. 828. Prisiis antiquorum, or saw-fish, rostrum of, iii. 97. 980. Proboscidia, organs and mode of locomotion of the, iii. 454. Proboscis of the elephant, iii. 875. Procerus muscle, iii. 728. Process and Processes : — acromion, i. 360; ii. 157, 158; iv. 600. angular, external and internal, i. 729. arciformes, iii. 680. articular of sacrum, s. 118, auditory, external, i. 733. auricular or maxillary, ii. 213. azygos (rostrum), i. 726. of the spheroid bone, i. 255. basilar, i. 726. 732. brevis mallei, ii. 546. ceratohyal, iv. 1124. cerebelli ad medullam oblongatam, iii. 693. cerebelli ad testes, iii. 677 . 686. 690. 693. 704. 722 O. ciliary, of choroid, ii. 180. of the vitreous humour, ii. 193, 194. clinoid, or posterior ephippial, i. 726. cochleariform, i. 734; ii. 544. condyloid, i. 732; ii. 215. coracoid, i. 359; ii. 157. coronoid , ii. 66. 215. of ulna, ii. 162. structure of the, ii. 163. cornu, of acetabulum, ii. 777. cribriformis, i. 730. cristate of the ethmoid bone, i. 729, 730. cubital, ii. 160. dentate, i. 251. ephippial anterior, or anterior clinoid, i. 728. posterior, or clinoid. i. 726. ethmoidal, i. 728 ; ii. 213. femoris, exterior, ii. 165. interior, ii. 166. frontal, i. 729. genial, ii. 214. gracilis, ii. 545. 561. hamular of lachrymal bone, iii. 90. of sphenoid bone, i. 727. internus, or sustentaculum cervicis tali, ii. 339. jugular, i. 732. lachrymal, ii. 213. lateral, i. 732. lenticularis incuclis, ii. 547. development, ii. 560. abnormal conditions of, ii. 561. longus mallei, ii. 546. malar, ii. 208. mammilliform fibrous, s. 125. mastoid, i. 734. maxillary, or auricular, ii. 210. 213. mental, ii 213. nasal, i. 729, 730 ; ii. 208. 210. or lachrymal, of lowest spongy bone, iii. 91. olecranon, i. 217 ; ii. 63. 66. 162. fracture of the, ii. 69. structure of the, ii. 163. olfactory, iii. 597- olivaris, i. 728. orbital of frontal bone, i. 730. orbitar, L 731 ; ii. 211. palatine, ii. 208, 210. pituitary, iii. 673. 703. primi genii, i. 729. pterygoid,!. 727; ii. 211. semicircularis, i. 733. spermatic, ii. 841. 844. spine of the scapula, ii. 157. spinous, posterior superior, s. 114. anterior superior, s. 114. inferior, s. 115. of the ilium, posterior superior, s. 11.5. anterior superior, ii. 500. of sacrum, s. 118. of sphenoid, i. 727, 728. 3 I 2 841 GENERAL INDEX. Process and Processes — continued. styloid, i. 734; iv. 1506. of temporal bone, i. 727, 728. of ulna, ii. 163, 164. transverse sacral, s. 118. turbinated, superior, i. 731. middle, i. 731. of the sphenoid bone, i. 72G. vaginal, i. 734. vermifoTm, inferior, iii. 678. 6S9, 690. superior, iii. 678. 68S. villus-shaped, of alar ligament, iv. 521. zygomatic, of temporal bone, i. 734. Prochaska^ G., summary of his work on the Functions of tlie Nervous System, iii. 721 C. Procidentia ani, i. 184. PuonucTs, Adventixious, iv. 71. dehnition, iv. 71. Group I. Solid adventitious products, iv. 72. Class I. Non-plastic products, iv. 73. Sub'Class I. Saline precipitates, iv. 73. § 1. Crystalline or amorphous particles, iv. 73. ^ 2. Masses, iv. 74 A. Calculi, or true calculi, iv. 74. a. urinary calculi, iv. 74. 1. uric acid calculus, iv. 77. 2. urate of ammonia calculus, iv. 78. 3. oxalate of lime calculus, iv. 78. 4. cystin or cystic oxide calculus, iv. 7S). 5. phosphate of ammonia and mag- nesia calculus, iv. 80. 6. neutral phosphate of lime cal- culus, iv. 80. 7. mixed pho.sphates or fusible calculus, iv. 80. neutral phosjihate of ammonia and magnesia, iv. 80. bibasic phosphate of ammonia and magnesia, iv. 80. phosphate of lime, iv. 80. 8. xanthic oxide (uric oxide, xanthin, urous acid) calcu- lus, iv. 80. 9. carbonate of lime calculus, iv. 81. 10. carbonate of magnesia, iv. 81. 11. urate of magnesia calculus, iv. 81. 12. urates of soda, potassa, and lime, iv. SI. 13. phosphate of magnesia, iv. 81. 14. chloride of sodium, iv. 81. fibrinous calculus, iv. 81. renal calculi, iv. 81. 256. calculi of prostate gland, iv. 82. pra'putial calculi, iv. 82. h. lachrymal calculi, iv. 82. c. nasal calculi, iv. 82. d frontal sinus, calculi of, iv. 82. €. calculi of month, |v. 82. /. salivary calculi, iv. 83. of i>arotkl gland, iv. 83. of teeth, iv. 83. g. tonsils, calculi of, iv. 83. h. pharynx and cesophagus, iv. 83. L gastro.intcstinal calculi, iv. 83. animal, vegetable, and inor- ganic nuclei of, iv. 8k k. biliary calculi, iv. 86. /. pancreatic calculi, iv. 86; s. 112. 771. seminal calculi, iv. 86. V. mammary calculi, iv. 86. 0. vaginal and pudendal calculi, iv 86. р. uterine calculi, iv 86. B. Concretions, or Pseudo-Calculi, iv. 86. a. elementary cell, iv. 86. b. foetal (petrifaction), iv. 87. с. placental, iv. 87. d vascular, iv. 87. arteries, iv. 87. 1. parietal — calcareous depo- sition in the coats of arteries, iv. 87. 2. central — arteioliths, iv. 88. veins, iv. 89. 1. parietal, iv. 8P. 2. central — phleboliths, iv. 89. c. lympliatic and lacteal, iv. 89.* f. in the serous and synovial cavities, iv. 90., g. in the fibrous membranes, iv. 90. h. cerebral concretions, iv. 90. f. uterine concretions, iv. 90. k. pulmonary, iv. 90. 1. artiiritic, iv. 90. m. cutaneous, iv. 90. Products, Adveivtitious — coiHinucd. \ Sub-class 11. Animalised precipitates, iv. 91, i ^ 1. Protein compounds, iv. 91. A. Albumen, iv. 91. a. albumen in the secretions, iv. 91. albuminaria from an unna- ' tural state of the blood, iv. ' 91. I albuminaria from morbid , states of the genito-uriiiary ' organs, iv. 92, ! albuminaria from accidental | admixture of genital pro- I ducts, iv. 92. j albuminaria from a doubtful ji cause, iv. 93. [ h. albumen retained, iv. 93. I| B. Fibrin, iv. 93. !| a. in the secretions, iv. 93. ^ C. Casein, iv. 94. i D. Globulin, iv. 94. j § 2. Fat, iv. 94. | A. Fatty infiltration, iv. 91. i a. in the liver, iv. 94. b. in the pancreas, iv. 95. I c. in the mamma, iv. 95. d. in the kidney, iv. 95. ' e. in the testicle, iv. 96. I J. in the lungs, iv. 96. \ g. arteries and cardiac valves, iv. i 96. I h. muscles, iv. 96. 1. voluntary, iv. 96. 2. involuntary, iv. 96. i. tendons, iv. 96. k. nerves, iv. 96. l. bones, iv. 96. 771. in adventitious products, iv. 97. I B. Fatty matters excreted in the fluid i or semi-fluid state, iv. 97. i a. in the urine, iv. 97. | b. in the faeces, iv. 97i c. in the saliva, iv. 97. d. in the sweat, iv, 97. C. Encysted fats, iv. 97. I atheromatous, meliccric, and sto- ! atomatous matter, iv. 97. ! analysis of encysted fats, iv. 97. j D. Cholesteric fats, iv. 98. ! in tumours, iv. 98. [ in granules, iv. 98. ■ in patches, iv, 98. ■ in scales, iv. 98. i development of masses of cho- I lestealoma, iv. 99. ' { 3. Sugar, iv. 99. saccharine diabetes, iv. 99. theories of the pathology of, iv> 99, 100. Class 11. Plastic products, iv, 100. Sub-class I. Blastemal formations, iv. 100. pliysical nature of, iv. 101. chemical constitution of, iv. 101. potential qualities of different blastemata, , iv. 102. Order I. Deposits, or non-stromal forma- tions, iv. 103. § 1. typhous deposit, iv. 103. §2. tuberculous deposit, or tubercle, iv. 104. § 3. purulent deposit, or pus, iv. ] 10. liquor puris, iv. HI. j plus corpuscles, iv. 111. analyses of pus, iv. 112. semi-fluid matters to be dis- tinguished from pus, iv. 114. «. mucus, iv. 114. b. softened fibrin, iv. 114. c. epithelial fluid, iv. 115. process by which pus is formed, : iv. 115, 116. § 4. melanic deposit, iv. 116. chemical composition, iv. 116. a. alteration of ha?malosine, iv 117. stagnation, iv. 117. 1 extravasation, iv. 117. ! chemical action, iv. 117. | h. introduction of black-coloured substances from without, iv. 117. into the lungs, iv. 117. disease of the lungs of colliers, iv. 117. § 5. diphtheritic deposit, iv. 118. white thrush, iv. 118. white cheesy material which i forms on blistered surfaces, iv. 118. GENERAL INDEX, 845 Products, Adventitious, Plastic — cotitinued. Sub-class I. Order II. growths, or stromal formations, iv. 118. elements of growths, iv. 118. a. granules, iv. 118. b. cells, iv. 118. contents of cells, iv. 119. c. nuclei of cells, iv. 119. d. fibrils, iv. 119. physiology of growth, iv, 120. mode of origin and increase, iv. 120. decay of growths, iv. 121. removal of growths, iv. 121. cicatrisation of the ulcerated sur- faces of growths, iv. 121. local and distant reproduction of growths, iv. 121. chemical composition of growths, iv. J2i, 122. pathology of growths, iv. 122. effects produced by growths on surrounding tissues, iv. 122. mechanical, iv. 122. vital, iv. 122. conditions oflocalisation, iv. 122. inoculability of growths, iv. 124. Sub-order I. Non-infiltrating growths, iv. 125. of protein basis, iv. 125. § 1. hteraatoma, iv. 125. § 2. sarcoma, iv. 126. § 3. cystoma, iv, 127. § 4. angeiectoina, iv. 127. § 5. melanoma, iv. 128. of fat basis, iv. 129. § 1. lipoma, iv. 129. § 2. steatoma, iv. ISO. § 3. cholesteatoma, iv. 130. of gelatin basis, iv. 130. § 1. fibroma, iv. 130. § 2. enchondroma, iv. 132. § 3. osteoma, iv. 134. of undetermined basis, iv. 135. colloma, iv. 135. Sub-order II. Infiltrating growths, iv. 136. cancer or carcinoma, iv. 136. Order 111. Pseudo-tissues, iv. 138. induration matter, iv. 138. simulating the natural tissues, iv. 139. extra-vascular tissues, iv. 139. epithelium, iv. 139. nail, iv. 139. 143. cartilage, iv. 139. simple vascular tissues, iv. 110. cellular tissue, iv. 140. serous tissue, iv. 140. fibrous and elastic pseudo- tis.sues, iv. 141. osseous pseudo-tissue, iv. 141. nervous pseudo-tissue, iv. 141, blood-vessel, iv. 141. erectile tissue, iv. 142. lymph vessel, iv. 142. fibrous and spongy cartilage, iv. 142. hair, iv. 142, tooth, iv. 142. cutaneous, iv. 143. mucous, iv. 143. glandular, iv. 143. muscle, iv. 143. unstriped fibres, iv. 143. Sub-class II. Germ-formations, or parasites, iv. 143. Order I. Animal parasites. See Entozoa. Order II. Vegetable parasites, iv. 143. Group IT. Liquid ailventitious products, iv. 144. Group 111. Gaseous adventitious products, iv. 145, Profunda artery, inferior brachial, i. 217. 465. superior, i. 217. 465. musculo-spiral branch of the, i. 217. clitoridis, s. 713. femoris, ii. 244. general relations, ii. 245. origin, ii. 245. branches, ii. 246. 1. external circumflex, ii. 246. a. ascending branch, h. 246. b. descending branch, ii. 246. c. circumflex branch, ii. 247» 2J internal circumflex, ii. 247. 3. perforating arteries, ii. 24S. first, second, and third, ii. 24S. operations on the profunda artery, ii. 257. vein, iv. 1412. Pro;inathous crania, iv. 1321. Progressive motion of animals. See Motion, Animal. Prolapsus ani, or procidentia ani, i. 184. recti, development of the rectum in, i. ISO, of the tongue, iv. 1158. Prolapsus — continued. uteri, falling of the womb, or bearing down, s. 684. development of the rectum in, i 180. a form of spurious hermaphroditism, ii. 690. cases recorded, ii. 690. vesicee urinaria inversa, iv. 952. Pro7uontory of the sacrum, s. 127. of tympanum, ii. 531. 543. groove or canal of, ii. 543. Pronation and supination of hand, how efifected, ii. 164. Pronator quadratus muscle, ii. 368. radii teres muscle, ii. 63. 366. Propago cinerea interna, iii. 732. Propensities of animals generally, i. 144. Prorodoiiy or toothed rolling animalcule, iv, 13. Prostate Gland, ii. 422 ; iii. 932 ; iv. 146. form, position, and adjacent viscera, iii. 933 ; iv. 146. levator prostata, iv. 147. ligamenta pubo-prostatica media et lateralia, iv. 147. uvula vesica, iv. 149. vesico-prostatic plexus of veins, iii. 933. intimate structure, iv. 149. liquor prostaticus, ii. 458; iv. 150. sinus pocularis, iv. 151. 1246. uterus cystoides, iv. 151. development of the prostate and vesicula prostatica, iv. 153. question of a prostate in women, iv. 1265. function of the prostate gland, ii. 459 ; iv. 153. morbid anatomy, iii. 934 ; iv. 154. hypertrophy, iv, 154. atrophy, iv. 156. inflammation, iv. 156. abscess, iv. 156. ulceration, iv. 156. tubercles, iv. 157. cancer, iv. 157. softening, iv. 712. fibrous tumours, iv. 1.57. cystic prostate, iv. 157. prostatic concretions, iv. 158. prostatic calculi, iv. 82. 159. analysis of, iv. 159- comparative’anatomy. iv. 160. prostate in Mammalia, iv. 160. in the ape, iv, 1(>U. in the tarsier, iv. 163. in the galeopitheci, iv. 160, in the roussette, iv. 160. in the dormouse, iv. 160. in the hedgehog, iv, 160, in the mole, iv. 160. in the bear, iv. 160. in the otter, weasel, and marten, iv. 170. in the ichneumon, iv. 160. in the dog and cat, iv. 160. in the hyena, iv. 160. in the marmot, iv. 160. in the rabbit, iv. 160. in the squirrel, iv. 160. in the rat, iv. 160. in the agouti, iv. 161. in the guinea-pig, iv. 161. in the elephant, iv. IGl. in the wild boar, iv. 161. in solipedes, iv. 161. in ruminants, iv. Ifil. in the slag, axis, and buflklo, iv. 161. in the cliamois, iv. 161. in the seal, iv. 161. in the cetacea, iv. 161. in the marsupial sub-class, iv. 161. in the opossum, iv. 161. in the wombat (doubtful), iv. 161. among amphibious reptiles are found glands ana- logous to the prostate, iv. 161. prostatic portion of urethra, iii. 924. 1246. Protein, iv. 162. analysLs of fibrin, albumen, and casein, iv. 162. tritoxide of protein, iv. 163. binoxide of protein, iv. 163. third oxide of protein, iv. 163. action of chemical agents on protein, iv. 163. protein and chlorine,— chloioproteic acid, iv. 163, 164. protein and nitric acid, — xanthoproteic acid, iv. 164. protein and sulphuric acid,— sulphoproteic acid, iv. 164. sulphobiproteic acid, iv. 164. protein and hydrochloric acid, iv. 164. protein and potash, iv. 1G4. erythroproliii, iv, 164. protid, iv. 164. leucin, iv. 164. nitroleucid acid, iv. 165. natural modifications of protein, iv. 165. fibrin, iv. 165. albumen, iv. 167. casein, iv. 168. globulin or crystalline, iv. 169. 3 I 3 8i6 GENERAL INDEX. ruoTEix — con/ini/cd. protein and its compounds in the vegetable kingdom, iv. 169. vegetable fibrin, iv. 169. albumen, iv. 169. casein, iv. 169. protein of food as an essential condition, s. S81. Vrotclminiha^ a class of parasitic animals, ii. 111. Proteus anguinus, organs of respiration of the, i. 99. vocal organs of, iv. HOo. muscular system of the, Hi. 543. j)elvis of the, s. 171. I^rothalliuvi of Lycopodiacca?, commencement of the deve- lopment of the, s. 243. Protidf iv. 164. kennesianus, or red snow, H. 117. pluvialis, mode of rcproiluction of the, s. 212. viridis, Agardh, or green matter of rrieslly, ii. 117. Protoi7ietrii, iv. 1252. 1265. Protoxoay i. 48. process of reproduction in Protozoa, s. 6. ova of I’rotozoa, s. [129J. Protuberance, annular, or pons Varolii, iii. G85. ProventriculiiSy or proper stomach of birds, s. 301. Proximate analyses of animal solids and fluids. See Or- ganic Analysis. Pryosoina, a genus of Tunicata, iv, 1192, ct seq. characters of the genus, iv. 1192. Psalferitony manyplies, omasum, or feuillct, of Ruminantia, s. 537. pA’cwf/o-nalculi, or concretions, iv. 86. See Products, Adventitious. Pscudopodia, a section of Polygastric Animals, iv. 5. Pjcwr/o-tetramera, a section of Coleoptera, ii. 8G2. p4r»^fu-trimera, a section of Coleoptera, ii. 863. characters of the section, ii. 863. Psoas, or lumbar, abscess, its resemblance to inguinal her- nia by direct descent, ii. 760. case of, ii. 797. Psocc muscles, ii. 828. psoas magnus muscle, i. 10 ; ii. 166. 838 j s. 137. parvus, i. 11 ; ii. 838; s. 137. 7’500-iliac aponeurosis, ii. 838. fascia, ii. 838. and ioiY.y meaning of the terras as used by the Greeks, ill. 143, 7iote. Pteris aquilina, antheridia of, s. 240. Ptyodactyliis, organs and mode of progression of, iii. 449. organisation of the, for flight, iii. 430. Plerodina, a genus of loricated Rotifers, iv. 408. Ptcromys volltans, or flying squirrel, anatomy of the, iv. 3f)8, et seq. flight of the, iii. 430. PTEROPODA,an order of Mollusca, i. 113; iv. 170. characters of the order, iv. 170. list of genera, iv. 170. organisation ami habits of Pteropoda, iv. 170, 171. peculiar method of swimming, iv. 171. Clio, iv. 171. integument, iv. 171. muscular system, iii. 541 ; iv. 172. locomotive apparatus, iii. 436; iv. 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. 175. mouth, iv. 176 ; s. 299. dental apparatus, iv. 176. salivary glands, iv. 432. generative system, iv. 177. Pteropus, digestive organs of tiie, s. 302. PAT/ygu-palatine, or superior pharyngeal, artery, i. 490; iii. 733. or posterior, border of the superior maxillary bone, ii. 20 f Pterygoid arteries, i. 4S9. fossa, i. 727. muscle, external, iv. 938. interior, i. 727. nerve, external, ii. 292. internal, ii. 292. or internal, surface of lower jaw, ii. 214. or posterior, border of palate bones, ii. 210. plate, internal, iii. 724. processes, i. 727 ; ii. 211. vein, iv. 1405. PtinidiL’, or dcatii-watch insects, ii. 862. Plyagura, a genus of Rotifera, iv. 401, ef seq. inelicerta, a species of Rotifeia, iv. 401. Pfyaliths, or calculi of the salivary glamb, iv. 83. Puberty, age at which it occurs, ii. 441, 442. climate, efll'cts of, ii. 442 ; iv. 984. variations, ii. 412. average age of puberty in Hindustan and England comiiared, iv. 1,338. structural and functional changes consequent on, ii. 439. See Generation; Ooary 0\u:, a family of Tunicata, iv. 1192, ct seq. characters of the family, iv. 1192. genera, iv. 1192. Python, anatomy of the, iv. 272, et seq. its powers of climbing, iii. 448. Pyura, a genus of Tunicata, iv. 1 191, c/ 5v’<7. characters of the genus, iv. 1191. Q- Quadratus femoris muscle, nerves for the, iv, 767 ; s. 138. lumborum muscle, i. 10; s. 137. fascia of, s. 138, menti muscle, ii. 225. relations and action, ii. 225. Quadriceps extensor muscle, iii. 77. rupture of tendon of, iii. 77- Quadrumana, an order of Mammalia, iv. 19k digestive organs of the, s. 304. teeth of, iv. 917. larynx of the, iii. 103. pancreas in the Quadrumana, s. 97. thymus gland in, iv. 1095. organs and mode of locomotion on the ground, iii. 455. conformation of the Quadrumana compared with that of man, iv. 1295, et seq. Weberian organ in, iv. 1416. 1428. division into Simi® and I,emurinae, iv. 195. I. Simi£e (Monkeys), iv. 195. 1. Simla? verowers of leaping of, iii. 475. Quagga (Eqnus quaccha), iv. 714. organs of voice of the, iv. 1493, Quill of tile porcupine, structure of the, s. 478. 498. Quinia, its power of restoring the normal production of animal heat, ii. 682. Quinsy, iii. 954. lingual, case of, iv. 1154. R. Rabbit (Lepus cuniculus), anatomy of the, iv. 370, et seq. mode of locomotion of the, iii. 454. nervous system of the, iii. 623. organs of voice of the, iv. 1491. urine of the, iv. 1281. Weberian organ in the, iv. 1418. 1428. Racemose glands, or glands of Brunn, s. 361, 362. Races of mankind. See Varieties of Mankind. brain of different races, iii. 665. Rachidian veins, or veins of the spine, iv. H04. 1409. Rachitis, i. 440. See Rickets. condition of the bones in, iv. 712. Rachiti&mus infantilis, s. 190. Radial Artery, ii. 526; iv. 221. 1407. course, ii. 363. its relations, iv. 222. a. in the forearm, iv. 222. b. in the wrist, iv. 222. c. in the palm, iv. 223. branches of the radial artery, ii. 529 ; iv. 223. 1. arteria radialis recurrens, iv. 223. 2. arteria superfidalis vote, iv. 223. 3. arteria anterior carpi radialis, iv. 223. 4. arteria dorsalis carpi radialis, iv. 223. other smaller branches, iv. 223. arteria dorsalis pollicis, iv. 223. arteria inagna seu princeps polticis, iv, 224. arteria radialis indicis, iv. 224. posterior perforating, iv. 224. varieties of the radial artery, iv. 226. varieties of origin, iv. 226. higii origin, iv. 226. varieties of distribution, iv. 226. diseases and injuries of the radial artery, iv. 226. aneurism, iv. 228. false aneurism, iv. 228. Radial nerve, i. 217 ; ii. 64. 160 ; iv. 759. or cephalic, veins, ii. 63; iv. 1406. cutaneous brunch of, ii. 362. R.adialis indicis artery, iv. 224. Radiata, organs of locomotion in the, iii. 440. nervous system of the, iii. 602. spermatozoa in Radiata, iv. 498. articulation, iv. 1505. ligament anterior, iv. 1506. posterior, iv. 1506. Radio-ulnar Articulations, iv. 223. 1. upper radio-ulnar articulation, iv. 228. round head of the radius, iv. 228. sigmoid cavity of the ulna, iv. 229. annular or orbicular ligament, iv. 229, synovial membraixe, iv. 229. movement, iv. 229. 2. lower radio-ulnar articulation, iv. 229. lower extremity of the radius, iv. 229. lower end or head of the ulna, iv. 229. triangular fibro-cartilage, iv. 230. synovial membrane, “ sacciforrais,” iv. 230. movement, iv. 23*'. pronation and supination, iv. 230. dislocation of these joints, iv. 231. diseases, iv. 231. Radius, ii. 65— 67. 163 ; iv. 1505. development, ii. 1G4. form, ii. 163. structure, ii. 164. surfaces, ii. 163, 164. tubercle of the radius, ii. 66. head of the, iv. 228. movement of, iv. 229. fractures of the radius, ii. 364. Rami of lower-jaw, ii. 214. Ramus ad tensorem tympani, ii. 555. anastomoticus magnus branch of the brachial artery, i. 217. auricularis nervi vagi, ii. 554. 556. pinnalis artery, i. 487. tympanicus nervi glosso-pharyngei, or nerve of Jacob- son, iii. 495. Rana temporaria (frog), nervous system of the, iii. 620. Ranatra linearis, nervous system of the, iii. 61U. Ranine artery, i 485, 486 ; iv. 1141. vein, iv. 1404. Rannla, the disease so called, iv. 420. 431. Raphi of the penis, iii. 912. of scrotum, iv. 438. 3 I 4 848 GENERAL INDEX, liaptores, or birds ot’ prev, i. 266. chara?ters of tlie. i. 266. pelvis of the, s. 169 Jlas)rcs^ or scratching birds, cliaractcrs of, i 26S. Hat ( Mils raltus), anatomy of the, iv. 371, el Si-q. digestive organs of the, s. 303. spermatozoa of the rat, iv. 476. of Canada (Gcoinys bursarius), iv. 586. sliort-tailed, or campagnol of France, iii. i7. water (Arvicola aniphibius), iv. 389. hare, or hay-maker (Bagoinys), its mode of providing f'lod for the winter, iii. 12. anatomy of the, iv. 374, et srq. mole (Spalax typhlus), anatomy of the, iv. 369, ct scq. porcupine of Azara (Echimys), anatomy of the, iv. 372. cl seq. lialaria cordata, i. 40. organs and mode of progression, i. 40 ; iii. 433. Ratllcsnake^ anatomy of the, 283, ct scq. its mode of progression, iii, 443. poison fangs of the, iv. 888. characters of the urine of the, iv. 1281. Itatlulus, a genus of Uotifera, iv. 404. llay, iii. 963, ct seq. brain of the, in. 764. muscles oftlie, iii. 543. mode and organs of progression of the, iii. 437. Ite-a^cnls employed in analyses, iii. 793. Jieasia, a genus of Myria{>oda, iii. 546, et scq. Henson ofman compared with tlie will of the lower animals, iii. 2, ct seq. of lichen-spores, s. 227. Lichens ; Repro- duction, Vegetable, Jyeccpiaculimi cliyli, iii. 206. 224. Hcctoaircthral space, iii. 932. triangular, iii. 932. Recto^utenne peritoneal folds, iii. 943, Hccto vesical fascia, iii. 922; s. 138. lamina of the pelvic fascia, iii. 933. folds, iii. 943 pouch, S- 369 Hecti muscles, i. 3. Hcctus abdominis muscle, i.8; s. 137. external, iii. 787. internal, iii. 787. inferior, iii. 787. superior, iii. 784. action of tiie recti inu-cles, iii. 788. nerve tor the rectus muscle, iv. 763. capitis anticus major muscle, i. 732 ; iii. 561. minor, i. 374 : 561. posticus major muscle, i. 373. 732. minor, i. 732 ; iii. 732. lateralis muscle, i. 732 ; iii. 561. femoris muscle, s. 137. Hcctiem. or straight gut, anatomy of the, i. 175.179 ; iii. 920; S.368. origin, course. &c., iii. 920. relations, iii. 921. coats, iii. 921. columns of the rectum, iii. 921. form and position, s. 368. tile three portions of tlie rectum, s. 363. first, or oblique, segment, s. So8. middle, or arcuate, segment, s. 3t>9. third, or terminal, portion, s. 3Gi). stiucture of the rectum, s. 369. arU'rios, i. 181. muscles of the anus, i. 180; s. 369. sphincter ani externus, s. 369. intermis, s. 36'J. levator ani, s. 369. nerves, i. 181. veins, i. 181. movements of the rectum, s. 370. defa?cation, s. 370. agents of the process of, i. 180 ; s. 37(i, 371. sketch of the phenomena of dcfa’cation, s. 371. mucous membrane of the rectum, i. 180 ; s. 371. contents of tlie large intestine, s. 372. peritoneum of the first portion of the rectum, iii. 94-1. abnormal and pathological conditions of the, i. GI. 64. 182. Rcciwrotl artery, radial, iv. 223. tibia), iii. 131. ulnar, iv. 22.5. anterior, iv.225. posterior, iv. 225. nerves, iii. 113. 594 ; iv. 816. effects of the lesion of the recurrent nerves in en- feebling ihe voice, iii. 895. branch of nervus vagus, iii. 887, 888. 901. of ophthalmic nerve, ii. 279. of pneumogastric nerve, s. 262. Hcd men of America, iv. 1358. nose, iii. 738. See Nose. Heilstart (Motacilla', nervous system of the, iii. 622. Heduvlus serratus, electricity of, ii. 82. Heed, abomasus, or caillette, of Ruminantia, s. 537. HerJ's of coral, furmution of, iv. 33. Reefs of coral — continued* mode in which they are converted into liabitablo islands, iv. 33. Reflex actions of nerves, iii. 720 K, 721 B. nerves, iii. 720 H. Refrigcratmg effects of cold water applied to the extre- mities, ii. 660. Regeneration of lost parts In Echinodermata, ii. 45, Regurgitation^ act ol, s. 316. causes of, s, 316. Reil. island (insel) of, iii. 672. Rein-deer^ larynx of the, iv. 1494. Rejuvenescence, s. 211. Relaxation, or diastole, of the auricles and ventricles of llie heart, ii. 602,603. See Heari’, Puysiulogy of. Ren. See Gland; Kidney. Renal arteries, i. 189 ; iv. 234, 235, 236. calculi, iv. 81. 256. plexus of nerves, iv. 982 ; s. 429. 552. vein, iv. 236. 238. 1413. capsules of fishes, iii. 1011. Rennet, s. 538. Reproduction, animal, organs of. See Generation; Ovum; Uterus and its Appendages; and the various classes of animals. Reproduction in animals generally, i. H5. fissiparous, i. 145. gemmiparous, external, i. 145. internal, i. 145. sexual, i. 145. ^ ol liermaphrodites, i. 145. animal and vegetable reproduction compared, i. 129. of lost parts in Crustacea, i. 760. in Gasteropoda, ii. 402. Reproduction, Vegetable (Vegetable Ovum), i. 122; s. 211. Fart I. Alga?, Fungi, and Lichens, s. 212. reproduction by means of zoospores, s. 212. under the most simple conditions, s. 212. confervoid Alga?, s. 213. the frond, s. 213. UlvaceiE, s. 214. zoospores developed in an organ specially des- tined to the purpose, s. 214. zoosporous reproduction in the olive-colourcd Alga?, s. 214. fructification in the Fucacea?, s. 215. the antheiozoidsof tlie Fucacea; compared with the zoospores of the other olive-coloured Algce, s. 216. zoosporous reproduction in the family of Vau- cheriacea?, s. 216. in the 8aprolegnia ferox, s. 217. Pilobolus, s. 218. zoosporous reproduction in some Fungi, s. 218. reproduction by conjugation, s. 218. in Dcsmidiae, s. 218. in Zygncmaceae, s. 219. in Pulinoglea macrococca, s 220. condition under which conjugation takes place among the Algie, s. 220. plants obtained by the germination of the zoo>pores of Saprolegnia, producing repro- ductive organs of an entirely different cha- racter, s. 220. reproductive 01 gans of the red Alga? or Floridear, s. 221. the first form — a ];olyspore, 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 zoosporoid bodies, s. 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, s. 223. Fungi and Lichens, s. 223. formation and development of the germ in Fungi, s. 224. basidios[)orous Fungi, s. 224. receptacle of Gcaster fimbriatus, s. 225. the theca or ascus of fungi, s. 22,5. the ascophorous Fungi represented by Uredineae, s. 226. Discomycetes and Pyrenomycetes, s. 226. researclies of MM. 'I'ulasne, s. 227. formation and development of the germ in Li- chens, s. 228. the thalliis, s. 229. the hypothallus, s. 229. the receptacles within or upon which the spores or spore* like organs arc pro- duced, s. 229. force with which the spores are dis- charged from the theca?, s.23U. antheridia of lichens, s. 230. pycnidis, s. 230. summary, s. 231. GENERAL INDEX. 849 Reproduction, Vegetable (Vegetadle Ovum) — cojiiinucd Part II. Higher Cryptogamia and Phanerogamia, s, 232. vegetative svstem among the lower Hepaticje, s. 232. first period — from tlie germination of the spore, s. 233. development of the antheridia, s. 2.33. development of tlie archegonia, s. 233. second period — fructification of tlie arche- gonia, s. 234. clianges preparatory to the development of ttie spores, s. 234. development of the spores, s. 234. vegetative system in Jungermanni® frondos®, 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. Mosse.s, s. 237- first period — germination of the spore, s. 2.38. development of the antiieridia and arche- gonia, s. 238. in the genus Phascum, s. 238. development of the irmt, s. 238. of the spores, s. 239. Ferns, s. 239. first period — germination of the spore, s. 239. antheridia, s. 239. archegonia, s. 240. origin of each archegonium, s. 240. the embryo, s. 241. sporangia and spores, s. 241. Equisetacc®, s. 241. first period — germination of the spore, s. 241. antheridiuin, s. 241. archegonium, s. 242. spores and sporangia, s. 242. Lycopodiace®, s. 243. commencement of the development of the pro- thallium, s. 24.3. archegonia, s. 243. embryo, s. 243. sporangia and spores, s. 243. Rhizocarpe®, s. 245. macrospore of Pilularia, s. 245. prothallium, s. 245. embryo, s, 245. sporangia and spores, s. 246. Phanerogamia, s. 246. Phanerogamia gymnospermia, s. 243. Phanerogamia angiospermia, s. 248. Hippuris vulgaris, s. 249. Orchis morio, s. 250, the anther and the pollen-cell, s. 251 . review of the analogies which j)resent them- selves in the liistory of the develop- ment of the rei)roductive 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, the pollen-cell, and the parent cell of four spores, s. ^2. 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, s. 253. Appendix. — On the relations which exist between the animal and vegetable kingdoms, as regards the function of reproduction, ii. 437 ; s. 256. Reptilia, a class of Vertebrate Animals, i. 115 ; iv. 264. definition, iv. 264. division into orders, families, and species, iv. 265. abdomen in Reptilia, i. 1. osseous system. See Osseous System. pelvis of, s. 170. osteology of Chelonia, iv. 265. pla^trum or ventral cuirass, iv. 266. ])elvis, iv. 267. bones of the carpus, iv. 267. feet, iv. 268. tarsus, iv. 270. osteology of Ophidia, iv. 272. myology of Chelonia, iv. 273. muscles of the neck and head, iv. 275. of the shoulder, iv. 275. of the arm, iv. 276. of the forearm, iv. 278. of the hand, iv. 279. of the thigh, iv. 279. of tlie leg, iv. 280. myology of Ophidia, iv. 281. muscles of the sj>inc, iv. 281. of the libs, iv. 281. Reptilia — continued. muscles of the head, iv. 282. anterior temporal, iv. 282. middle temporal, iv. 282. posterior temporal, iv. 283. muscles of the head of the rattlesnake, iv. 283. mu>cle$ of the throat, iv. 284. organs and mode of progression of the Cheloni.a, iii. 445. myology of the salamander, iv. 285. muscles of the head, iv. 285. of ihe trunk, iv, 285. of the extremities, iv. 286. temporo-maxillary articulation in reptiles, iv. 941. teeth of Reptilia, iv. 287. 882. number, iv. 883. situation, iv. 883. form, iv. 883. attachment, iv. 883. substance, iv. 884. structure, iv. 884. development, iv. 884. batrachian modifications, iv. 885. poison fangs and poison glands of serpents, iv. 887, 888. of saurians, iv. 889. crocodilia, iv. 288. 895. development, iv. 896. of the lizard, iv. 288. of the boa constrictor, iv. 289. poison fang of serpents, iv. 290. poison apparatus of the viper, iv. 291. development of teeth, iv. 291. tongue of reptiles, iv, 292. digestive organs of, s. 264. 300. oesophagus, s. 300. stomach, s. 296. 300. intestine, s. SCO. in Batrachia, s. 301. in Ophidia, s. 301. in Chelonia, s. 301. salivary glands of Reptilia, iv. 432. viscera, iv. 297. renal organs of Reptiles, iii. 1/5 ; iv. 233. thymus gland of Reptiles, iv. 1098. tliyroid gland, iv. 1108. lymphatic system, iv. 300. lymphatic hearts, iv. 302. venous system, iv. 303. arterial system, iv. 303. organs of respiration, iv. 306. circulation of the blood, i. 96. 601 ; iv. 307. the heart, iv. 307. nervous system, iii. 620 j iv. 3C9. the brain, iv. 309. sympathetic system, iv. 312. organ of hearing, iv. 313. organ of vision, iv. 314. appendages to the eye, iv. 514. lachrymal apparatus, iv. 316. urinary apparatus, iv. 316. the kidneys, iv. 316. organs of generation, ii. 419. male organs of generation, iv. 317. spermatozoa of, iv. 480. female organs of generation, iv. 321. oviducts, iv. 321. development of the egg, iv. 322. external forms of different eggs of reptiles, s. 50. tegumentary system, s. 324. 941. musk gland of the crocodile, s. 325. anal glands, s. 325. optic nerves of, iii. 764. eyelids in Chelonia, iii. 95. glandule of Harder in, iii. 93. secreting and derivative apparatus in, iii. f-8. ciliary motion in Reptiles, i. 628. animal heat of Reptiles, ii. 649. Reservoirs of breasts, iii. 248. See Mammary Glands. Rcspiratio7i. artificial, i. 263, 264. Respiration, organs of, s. 258. respiratory a[>paratus of animals generally, i. 140. 143. I. Human and Mammalian, s. 258. definition, s. 258. lungs, s. 258. in man, s. 258. apices of the lungs, s. 258. trachea in man, s, 258. structural anatomy of the trachea, s. 259. tracheal mucous membrane, s. 259. cilia, s. 260. tracheal glands, s. 260. fibrous structures, s. 261. tracheal cartilaginous rings, s. 261. tracheal muscles, s. 2n2. arteries of the trachea, s. 262. bronchi, s. 262. the bronchi divide on no constant or regular plan, s. 264. ultimate ])uhnonary tissue— lobules—historical bibliography, s. 264. minute anatomy of the lobule, s. 266. general index. S50 Kespiratiom, organs of — continued. ultimate air-cclls of the Inng.s, — Vesicula? s. ccllulaj H(ireje, s. Malpighianae ; al- veoli pulmonum of Ilossignol, s. 2G8. minute structure of theair-cells, s. 270. ihe epithelium of the air-passages and cells, s. 270. tiie elastic tissue of the air-cells, s. 27-2. 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. broncliial veins, s. 275. anastomoses betweet) the bronchial and pulmonary systems of vessel.s, s. 275. use of the nose in respiration, iii. 7- 5. breathing by the nose and mouth comj>arc(1, iii. 735. See also Thouax. II. Comparative anatomy, iv. 270. in Acalepha?, i. 44. in the Annelida, i. 170. in Arachnidans. in Eeliinoderinata, ii. 40. in Cetacea, i. 579. in Crustacea,! 177. in Entozoa, ii. 13G. in Gasteropoda, ii. 389. in Mar.su[)ialia, iii. S('9. in Mollusca, iii. 365. in Monotremata, iii. 391. in Myriapoda, iii. 549. in I’achydermala, iii. 872. in Pteropoda, iv. 173. in Quadrumaiia, iv. 209. in Keptiles, iv. 306. in Rotiftra, iv. 413 in lluminantia, s. 512. respiratory organs of birds, i. 341 j iv. 276. 333. s. 276. of reptiles, s. 278. temporary brancliis of Amphibia, i. 98: s. 278. temporary external gills, s. 279. external gills of the Salmandridri*, s. 279. internal temporary branchia? of Amphibia, s. 280. air-bladder of Fishes, s. 281. lungs in Batrachia, s. 282. re.spiratory organs of Fi.shes, iii. 985 ; s. 286. mucous membrane of tlie branchiffi, s. 287. vascul.ar system of the branchiae, s. 287. m’niute circulation of the branchia}, s. 288. cartilage, or supporting system, of the branchiae, s. 289. III. Morbid anatomy of the lungs and air-passages, s. 291. inflammation of tlie bronchi : — a. acute bronclhtis, s. 292- b. chronic broiKhiiis, s. 292. c. plastic broiu’liitis, 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 tlie 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 hroiichitis, s. 293. bronchial croup, s. 293. astiimatic atfections, s. 293. forms of disease recognised by English pathologists, s. 293. inflammation of the vesicular tissue, s. 293. engorgement, s. 29.3. hepatisation, s. 293. grey hep.atisation, s. 293. gangrene, s. 293. cancer of the lung, s. 293. phthisis, s. 293. seat of pulmonary tubercle, s. 2.93. nature of tnbcrcuious matter, s. 293. mechanism of empliy'sema, s. 293. desquamation of the epithelium of the air-i)assagcs, s. 293. diseases of the larynx, iii. 114. See Larynx. Respiration, function of, iv, 32.5. preliminary remarks, iv.S25 — 327. respiration of plants, i. 1.32 ; iv. 328. respiration of animals, i. 132 \ iv. definition, iv. .329. conditions which regulate the energy of the function, iv. 329. Respiration, function of — continued. respiratory membrane, iv. 331. gills or branchia, iv. 331. trache?e, 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. 7-21 I. tiie medulla oblongata the centre of respiratory movements, iii. 722 K. importance of the oxygen of the atmosphere to animal existence, iii, 31. relation of tlie circulation to, i. 675. relation wliich the pulse bears to the re.'^piration, iv. muscular movements in inspiration and expiration, iv. 334. measure of force of the muscular movements ofinspiration and expiration, iv. 336. frequency of the respiratory muscular move- ments, iv. 338. motions of the glottis during, iii. 113. excitement of 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. 7C6. stale 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. 312. 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. fa^ting, iv. 347. alcohol, iv. 347. conditions of the mind, iv. 3-18. 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, cliemical 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 tlie lower parts of the respiratory apparatus become intermixed, iv. 352. 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 tlie 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, liestijorm bodies, iii. 678, 679. 682. function of the, iii. 722 K. Retc mucosuin, or rete Malpighii, iii. 490; iv. 1333. testis, iv. 977. 979. Rciepedes of Scopoli, i. 266. Reticidu7n, bonnet, or honeycomb, of the second stomach of lluminantia, ii. II. of the camel, s. 536. Retiform or reticular plexus, s. 712. Retina., ])<^ripheral 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. M52. GENERAL INDEX. 851 Bclinacula of Barry, s. 551. 560. Retractility of muscles, iii. 524. Retractor anguU oris muscle, iii. 566. Retrahentes auriculam muscles, ii. 552. Reviviscence of hibernating animals, phenomenon of, ii. 774. causes of, ii. 774. Rhagades, or fissures, of the tongue, iv. 1156. 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. Rheumatis77i^ characters of the urine in. iv. 1293. chronic, or nodosity of the joints of the hand, ii. 518. of the liip (or cl ronic rheumatic arthritis), ii. 798. anatomical characters ii. 80l. history of the disease, ii- 798. similar disease affecting other articula- tions. See Elbow 3 Hand j 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 Pachvdeiimata. 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. RhizocarpecBy vegetative system of, s. 245. macrospore of Pilularia, s. 245. prothallium, s. 245. embryo, s. 245. sporangia and spores, s. 246. RkizoduSy teeth of the, iii. 978. RUizophaga, a tribe of Marsupialia, iii. 267, et scq. genera of, iii. 267. Rhizophysa melon, i. 38. Rhizopoda, mode of reproduction of the, s. 6. ova of, s. [129.] Rhizostoma cserulea, i. 40. digestive organs of, i. 42. mode of progression of, iii. 433. ova of, s. [129.] Rhomboideus muscle, iii. 729 j iv. 755. scapulae muscle, iv. 576. Rhynchophora, a tribe of the order Coleoptera, ii. 862, characters of the tribe, ii. 862. Rhynchosaurus, teeth of, iv. 890 Rhypnphaga, a sub-tribe of Insecta, ii. 859. Rhythm of the heart, ii. 614. Rhydsma, reproductive system of, s. 227. Rhyzoyni-s of Sumatra, anatomy of the, iv. 371, ct scq. Ribs, iv. 1024. classification of the ribs, iv. 1025. general characters, iv. 102.5. special characters, iv. 1027. pleura costalis, iv. 2. cartilages of the, i. 249. See Tciorax. Rice, properties of, as food, ii. 13. Rickets (rachitis), i. 44U ; s. 189. causes of, i. 'i40. consequences, immediate and remote, i. 440. symptoms, i. 440. cases of, in the foetus in utero, ii. 337. Ridge, canine, ii. 207. malar, ii, 208. mylo-hyoid, ii. 214. turbinated, 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. Rima glottidis, in. 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. snake (Col. natrix), nervous system of, iii. 620. Rings, cartilaginous, of the trachea, s. 261. of Crustacea, i. 753. Risorius Santorini muscle, iii. 566. RiS7is Sardoiiicus, cause of the, ii. 6. Rivinus, 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. Rodentia, an order of Mammiferous Vertebvata, iv. 363, bones of the cranium of various species, iv. 3G9. face, iv. 374. carpus, iv. 379. clavicle, iv. 38U. PvODENTia — 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 j s. 303. stomach, iv. 386. intestinal canal, iv. 389. liver, iv. o90 pancreas, iv. 390; s. 97. spleen, iv. 390. thymus 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. Rosenmilller, organ of. See Parovariutn, s. 593. Rotation of joints, i. 256. Rotatoria, or Rotifera. See Rotifera. 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 viulity after apparent perfect desiccation, iv. 398. Ehrenberg’s division into families, iv. 40o. 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.] ovarian ova, s. [118.] spermatozoa of Annelida, iv. 498. Khrenberg’s summary of the general relations of the Rotifera, iv. 415. Round ligament of the liver, iii. 936. Round-worm ( Ascaris lumbricoicles), ii. 125. Rove-beetle (Creoi>hilus maxillosus), ii. 863. liugcB of mucous membrane of the stomach, s. 323. penniform, of uterus, s. 629. Rumen, or paunch of Ruminantia, s. 302. structure of the rumen, s. 535. Ru.minantia, an order of Mammalian Quadrupeds, s. 506. essential characters of the order, s. 506. of the sub-orders — Camelidce, s. 506. CervidtB, s. 508. Antelopid«e, s. 508. jEgoscerid®, s. 508. Bovida?, s. 508. Osteology, s. 508. bones of the cranium, s. 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. niaxillaries, s. 513. lachrymals, s. 513. palatines, s. 513. vomer and ossa spongiosa seu turbinata, s, 5i5. interior maxilla or jaw-bone proper, s. 515. cranial peculiarities, s. 516. horns, s. 516. vertebral column and bones of the trunk, s. 519. atlas in camels, s. 520. axis ordentata, odontoid process of the, s. 520. dorsal vertebra;, s. 520. ribs, s. 520. pelvic bones, s. 156. 521. bones of the anterior extremity, s. 521 . scapula, s. 521. humerus, s. 521. bones of the fore-arm, s. 521. carpal bones, s. 522. metacarpals, s. 522. phalanges of the cloven font, s. 522. 852 GENERAL INDEX. Ru.mixantia — continued. bones of the posterior extremity, s. 522. femur, s. 523. patella, s. 523. tibia, s. 52.3. bones of the tarsus, s. 523. metatarsals, s. 523. Myology of Iluminants, s. 523. paiiniculus carnosus, s. 523. musculus cutaneus faciei, s. 52K m. cutan. humeri, s. 524. m. cutan. maximus, sen abdominis, s. 521. other muscles of tiie same category, s. 524. muscles of the head and trunk, s. 524. trapezius, s. 524. llie broad muscle represented in the human subject by the splenius capitis and s[)lenius cervicis, s. 525. trachelo-inastoideus, s. 525. great compk XUS and digastricus colli, s. 525. transvcrsalis ccrvicis, s. 525. scaleni muscles, s. 525. longus colli and recti, iii. .52(3 sterno-mastoideus or maxillaris, s. 523. rectus capitis anticus major, s 526. liyoid apparatus, s. 526. muscles proper to the hyoid chain of bones, s. 527. sterno-hyoids and sterno-thyroids, s. 527. oino-hyoid, muscle analogous to, s. 527. stylo-hyoid, s. 527. ceratoido-latcralis, s. 527. inasto-styloid, s. 527. mylo-iiyoid, s. 527. geuio-hyoids, s. 527. muscles connected with the hyoid apparatus of the girafle, s. 527. muscles of the shoulder and fore-limb, s. 528. levator angulis scapulae, s. 528. rhomboideus major and minor, s. 518. serratus magnus or major, s. 528. minor, s. 528. latissimus dorsi, s. 528. pectoralis major, s. 528. ambibracliialis communis, s. 529. abductor longus brachii, or abd. brach. supe- rior, s. 529. supra-spinatus and infra-spinatus, s. 529. teres major, e.xternus, minor, and iiUernus, s. 529. coraco-bracliialis, s. 529. biceps brachii, coraco-radialis, or flexor cubiti longus, s. 529. braciiialis internus, or flexor cubiti longus, s. 529. extensor cubiti, s. 529. brevis, s. 529. brachialis externus, s. 529. anconeus internus, s. 529. protiator teres, s. 529. extensor carpi radialis, s. 529. flexor car[)i radialis, s. 539. extensorcs digitorum, longior et brevior, s. 530. abductor pollicis, muscle corresponding to, s. 530. flexores carpi ulnaris externus ot internus, s. 530. flexor digitorum sublimis et flex, dig, pro- fundus perlorans, s, 530. muscles of the liaunch and hind-limb, s. 530. gluteus maximus, s. 530. tensor fascia? latae, s. 530. biceps fenioris, or vastus longus, s. 530. iliacus internus, gluteus medius et minimis, and pyriformis, s. 530. obturator externus et internus, the gemclli, quadratus fcinoris, 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 CamelidEp, s. 531. im]>ortant changes co-existing with the shedding of the antlers in the solid-horned lluminautia, 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. l)apilla? 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. cesoj)hagus, s. 535. stomach, ii. 11 ; s. 535. paunch, rumen, ingluvies, or panse, s. .302. 535. reticulum, bonnet, or water-bag, s. 536. psaltcrium, manyplies, omasus, or feuillet, s. 302. 537 IlUMiNANTlA, stomach — continued. reed, abomasus, or caillctte, s. 302. 537. ruminating function, s. 537. concretions found in the paunch and reticulum, s. 538. the bezoar stones formed in the stomach of the chamois, s. 538. inverted action of the cesophagus in returning tlie 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 Kuminantia compared with those of the Carnivora, i. 479. larynx of the, iii. 103. organs of circulation, s. 541. ot 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. Ru77iinationy or chewing the cud, ii. 11. causes of, ii. II. I)ower of rumination possessed by some individuals, s. 319. mode in which it is eflected, s. 319, 320. Runnings iii. 471. principles upon which walking and running difler, iii. 471. 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 the pia mater, iii. 635. in the pineal gland, iii. 635. SaCf lachrymal, iii. 91. finis C33CUS sacci lachrymalis, iii. 91. Sacc2ili., or cysts, of the urinary bladder, i. 393. Saccnlus, ii. 569. laryngis of Hilton, iii. 112. size, form, and uses, iii. 112. rotundus, ii. 538. Sacral ganglia, s. 425. artery, middle, i. 197 j ii. 828. lateral, ii. 830. origin and distribution, ii. 830. canal, s. 118, 119. crest, s. 119. foramen, s. 118, 119. nerves, iv. 765; s. 641, note. anterior branches of, iv. 765. first, second, tliird, 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-cocci/geal 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. articulations, i. 249 j 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, s. 124. ilio-lumbar, s. 124. sacro-sciatic, great, s. 124. lesser, s. 124. lateral sacro-iliac, or posterior lateral iliac, of Scemmering, s. 125. movements of the joint, s. 125. ossification of the, s. 207. Sncro-lumbaUs muscle, i. 10. 372 ; s. 137. GENERAL INDEX, 653 5/rn*(?-/7w/6rtr articulations, coalescence of t!ie bones com- posing the, s. 207. Sacro-sciaiic ligament, great, s. 124. lesser, s. 124. ossification of the, s. 207. notch, s. 127- Sacro-spinalis muscle, i. 10. Sacro-vertehraly or lumbo-sacral, ligament, s. 121. Sacru7ti^ i. 367 ; s. 118. its office, s. 1 18. 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. Saf^itlal suture, i. 737. Sahara^ characters of the Tuaryks of, iv. 13'7. Salamander (Salamandra terrestris), myology of the, \v. 285, et scq. American (Menopoma alleganiensis), cranial bones of the, i. 92. vertebrw in the, i. 93,94. teeth of the, i. 95. cutaneous secretion of the, i. 102. eyelids of salamanders, iii. 95. ciliary motion in the larva of salamanders, i. 628, 629. 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. 127 ; iv. 415. method of analysing, iii. 811. quantity secreted during the day, iv. 415. physical qualities, iv 415, specific gravity, iv. 416. chemistry, iv. 41$. '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 teetl), 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 saliva, 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, pt^aliths, or tartar deposited 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, \v. 404. excretory canal, or Wharton’s duct, iv. 424. arteries, veins, nerves, and lymphatics, iv. 424. sublingual gland, iv. 424. position, form, anckdimensions, iv. 425. ducts of the sublingual gland, iv. 425. arteries, veins, lymphatics, and nerves, iv. 425. subsidiary salivary glands, iv. 425. labial glands, iv. 426. buccal glands, iv. 426. 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 fistulae, iv. 431. ranula, iv. 420. 431. morbid condition of the labial glands, iv. 431. Comparative anatomy, iv. 431. Entozoa, iv. 431 . Echinodermata, iv. 431. Myriapoda, iv. 431. Insecta, iv. 431. Cirrhopoda, iv. 432. Pteropoda, iv. 432. Gasteropoda, ii. 388 ; iv. 432. Cephalopoda, i. 532 ; iv, 432. Pisces, iii. 982 ; iv. 432. Reptilia, 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. Snlivai-i/ mucus, chemical characters of, iii. 482. Salivationy mercurial, analysis of the saliva of, iv. 421. spontaneous, analysis of the saliva of, iv. 421. Sal)72on, migration of die, 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 ca?ca of the salmon, s. 93. SahnonidcUy a family of Fishes, iii. 957. Salpa, a genus of Tunicata, iv. 1193, et seq. characters ofthe genus, iv. 1193. Salpa cristata, mode of progression ofthe, iii. 434. SaipidiTy a family of Tunicata, iv. 1192, et seq. characters ofthe family, iv. 1192. mode of reproduction of tlie, s. 23. Salpina, a genus of K'ltifcra, iv. 406. Salty common, or chloride of sodium, ofilee it subserves with reference to nutrition generally, ii. 15 j 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. SaltatoriCy a group of Marsupialia, iii. 261, et scq. Salts of corn, s. 393. Snncturiajiy or insensible, perspiration, iv. 841, 842. Sandy grains of, in the jna mater, iii. 635. in the pineal gland, iii. 677- Sandivich Islanders, physical characters ofthe, iv. 1362. Sanouijicationy process of, entirely or partially arrested during the sleep of hibernating animals, ii. 768. Sanguine temperament, iv. 936. Satiguineous excretions from the bladder, i. 401. Saiitoidniy fissures of, or incisurs Santorini, ii. 553. muscle of, ii. 553. tubercles of, iii. 102. Saphena vein, i. 15. 148 ; ii. 238 3 iv. 61. internal or long, iv. 1411. cutaneous and communicating brandies, iv. 1111. posterior, external, or short, iv. 1411. major, iii. 128. course of, ii. 351. minor, iii. 128. course of, ii. .351, Saphenous nerve, ii. 352 ; iv. 764. cutaneous tibia! or reflected branch, iv. 764. accessory, iv. 763. external or communicans tibialis, iii. 130. internal, iii, 130. short, iv. 76-3. tibial, iv. 770. Saphenous trunks, iv, 1411. Sappho, ii. 686. Saprolcgnia ferox, mode of reproduction of, s. 217. plants obtained by the germination of the zoospores of Saprolegnia, producing reproductive organs of an entirely different character, s. 220. Snreina ventricuii in the fluid of pyrosis, iv. 141. Sarcolemmay or tunic of the elementary fibre of muscle, iii. 512, See Muscle. trichinia} of sarcolemma, iii. 512, 513. Sarcojua, iv. 126. composition of, iv. 127. adipose, i. 63 ; iv. 129, SO. medullary, in the cranium, i. 746 of liver, Hi. 193. of pancreas, s. 112. Sarcoynatous poh pi of the nose, iii. 740. SarcophagOy a tribe of IVtarsupialia, iii. 258, ci scq. genera of. iii. 258, 259. Sarcous elements, or primitive particles of muscle. Sec Muscle. tissue. See Muscle. 851) GENlillAL INDEX. Slardoivc smilo, cnuso of the, ii. 6. Sarturius muscle, s. 137. Saiellite nerve of the femoral artery, iv. 763. veins of brachial artery, iv. 1407. of gustatory nerve, iv. J404. of the right subclavian artery, iv, S16. Satietify effect of the lesion of the vagi uijon the sensation of, iii. 809. Satinmia Carpini, ovum of, s. [113.] pavonia minor, nervous system of the larva of the, iii. 611,612. Safijriasisy iv. 985. Sauna, an order of Reptilia, iv. 265, ct scq. ciliary motion in, i. 631. pelvis of the, s. 170. dental system of the, iv. 889. tongue of, iv, 1 147. pancreas of, s. S5. thymus gland of, iv, 1098. thyroid gland in, iv, 1108. muscles of, iii. 543. organs and mode of locomotion oftlie, iii. 448. Saiv-Jish, osseous spines of, i. 255. rostrum of, iii. .977. 980. Saw-JUcs, a family of Insccta, ii. 865. ravages of its larva in turnip-fields, ii. 86.5. 870. migration of, in myriads, iii. 16. organs of generation of the, ii. 992, 903. Scal.\ii Region (descriptive and surgical anatomy of), iv. 433. definition, iv. 433. muscles, iv. 433. See Arm ; Back; Neck. supra- and infra spinal fossae, iv. 434. sujira-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. 4.35. 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, 407. . ■ veins of the scapular region, iv. 437. lymphatics, iv. 437- u.ses of the scapula, iv. 437. furuncular infiammation of tlie scapular region, iv. 438. anthrax, iv. 438. chronic abscesses, iv. 438. fractures, iv. 438. ablation, iv. 438. 5c/7/ii//o-liumcral articulation, iv. 572. See Suoulder- JoiNT (normal anatomy). Scajddium^ a genus of Kotifera, iv. 404. Scarlalina., syncope induced by, i. 797. Scarlatina anginosa, iii. 117. Scarf, or parrot-fishes, dental apparatus of, iii. 979 ; iv. 871. 8/8- Scents, or odorous emanations. See Smell. Schindylesis, form of articulation, i. 255 ; ii. 219 ; iii. 90. ScliLsiozomus reflexus, iv. 949. Schneideriany or pituitary, membrane, iii. 726. 730. Schwann, white substance of, iv. 1140. Sciii'nida:, a family of Fishes, iii. 956, et scq. 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 oftlie, s. 182. vein, iv. 1412. Semcidee, a family of Reptilia, iv. 265, ct seq. Scuicoid lizard.s, teeth of, iv. 891. Scincus officinalis, teeth of, iv. 891. Scirrhns cancer, characters of, i. 515; iv. 137. of mamnicp, iii. 255. Madder of scirrhus of maiumse of Dr. Benedict, iii. 255. of the membranes of the urinary bladder, i. 402. of the muscular substance of the lieart, ii. 637. of pancreas, s. 111. of thyroid gland, iv. 1116. Sciiirns vulgaris, or squirrel, anatomy of the, iv. 730, ct s''q. sj)crmato2oa of the, iv, 475. Sclerodcrmes, a family of Fishes, iii. 957, et scq, Sclcrogenida, 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, it. 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. C22. Scolopendra, a genus of Myriapoda, iii. 547, et scq. Scolopendrn morsilans, nervous system of the, iii. 609. •' Scolopcndrid(U, a family of Myriapoda, iii. 547, et scq. Scolytus destructor, its ravages amongst elm trees, ii. 862. pygmseus, its ravages amongst oak trees, ii. 862. Scomber scombrus, or mackarel, eyes of, iii. 1002. thyiinus (tunny), iii. 975. 994. Scoynheridee, a family of Fishes, iii. 9~>7. Scorbutus, effects of, on the action of the heart, i. 798. Scorpion-f\\es (I^anorpina), ii. 864. l^inorpa communis (common scorpion-fly), ii. 864. Scorpions, alimentary canal of, i. 204. apparatus for secreting the irritating or poisonous fluid, i. 208. eyes of, i. 207, 208. generative system of, i, 210, nervous system of, i. 205. pectines of, i. 21 1. digestive organs of the, s. 299. muscular system of the, iii. 539. ova of scorpions, s. [115.] uses of scorpions in warm climates, iii. 27. See Araciinida. Scratchuig birds ( Rasores), cliaracters of, i, 268. Scrubiculus 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 frem a scrofulous cause, i. 450. caries cf tlie spine, i. 451. progress of tlie 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. sejitum 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 adijiose tissue in, i. 62. Snitibranchiata, ii. 379. See Oasteropoda. Scutigern, a genus of Myriapoda, iii. 546, ct scq. GENERAL INDEX, 855 Scutigcra livkla, iii, 547. Scutigeridce^ a family of Myriapoda. iii. 5-lG, scq. characters of the family, iii. 54G. Scutipedes of Scopoli, i. 2o6. Scutula Wallrothii, spermagonia of, s. 230. })ycnidis of, s. 23]. Scyllcea pelagica, nervous system of the, iii. 606. ScJjphia, d. family of Pcrifera, iv. 65, characters of the family, iv. 65. of cochlea, ii. 532. Seu, phos[>horescence of the, iii, 198, ct seq. See Lumi- nousness, Animal. physical effects produced by a particular display of the I’uminousness of the sea, iii. 198. Sea-aneuwne, digestive organs of the, s. 296. Sea-gull (Larus cyanorhynchus), nervous system of the, iii. 622. Sea-jelly, or sea-nettle, i. 35. See Acalephj^. digestive organs of the, s. 297. Sea-mouse, description of the, i. 617- ciliary motion in the, i. 618. Sea-scurvy, condition of the blood after death from, i. 418. Sea-sickness, iv. 1174. Sea-urchin, ii. 3(», et seq. See Echinodermata. ciliary motion in the, i. 615. 617. See Cilia. Sea-water, its absorption of the ray.s of liylu transmitted through it, and loss of transparency, iv. 1438. Seal, common (Phoca vitulina), organs of voice of the, iv. 1491. Weberian organ in the, iv. 1418. grey (Halichccrus grypbus), dentition of the, iv. 915. Seasonmgs of food, s. 395. See l'ot)i). 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. 0 of the nose. iii. 729. follicles of the vulva, s. 711. Sebu?n, i. 57- Second intercostal nerve, i. 217. jSe’CJ'ef/wg canals, ii. 487, 488. Secretion,!. 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. 444. 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 otf by decaying bodies, iv. 456. hydrocarbon of biliary secretion, iv. 458. nature of fWcal 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 ]>rocess, iv. 464. on the secretion of milk, iv, 464. by mental emotion, iv. 464. on the secretion of saliva, iv. 466. gastric juice, iv, 466. tears, iv. 466. 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. 80^ of milk, iii. 811. of bile, iii. 811. of saliva, iii. 812. Secretions Carnivora, i. 481. See Carnivora. follicles producing peculiar secretions, i. 481, 4S2. of Polygastria, iv. 16. of Mammalia, hi. 235. xSeeds, dormant vitality of, iii. 156* Seeing. See Vision. Seg7)ientntion of the ovum of animals, process of, s. [138.] bee Ovum. Sctaginella, vegetative system of, s. 243. Sella turcica, i, 726, Semen, ii. 457 ; iv. 472. definition, iv, 472. histiological elements of the semen, iv. 472. spermatozoa, iv. 472, liquor seminis, 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. 4S4. in Cephalopoda, iv. 485. in Gasteropoda, iv. 435. in Acephala, iv. 487. in Articulata, iv. 488. in Insecta, iv. 4S8. in Arachnida, iv. 4*^0. in Mynapoda, iv. 492. in Crustacea, iv. 493. in Annelida, iv. 496. in Bryozoa, iv. 497. in Ro'tifera, iv. 498. in Radiata, iv. 498. in Echinodermata, iv. 498. in Acalephte 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 j)roperties, ii. 458; iv. 505. circumstances on wlhch the (ecundating projicrty 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. &.)1. 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. vesiculje seminales, ii.458. See also VEsicuLiE Semi- NALES. physiological office of the semen, iv. 507. See also Ovum ; Semen. Sc7nib7ilb, or bulb, of the vagina, s. 712. Semicircular canals, h. .530. 53/. ampulla, U. 530, 531. 557. horizontal, ii. 531. posterior, ii. 531. superior, ii. 531. development ot the, ii. 558. function of the, ii. 569. 577. process, i. 733. tsFnia, iii. 675. Seynidiurna, a section of Insects of the order I.ei>idoptera, ii. 867. characters of the section, ii. 867. Semilunar, or lunar, bone of carpus, ii. 505 ; iv. 1506. articul.ations, ii. 50.5. Scynilunar cartilages of knee-joint (cartilagines falcatce, s. lunatceh iii. 45. ganglion, ii. 298 ; s. 641, note. folds, 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. Se7ni7nembranosvs muscle, iv'. 61 ; s. 137. nerves Ibr the. iv. 768. Se77iinal cercari®, ii. 112. Sec Entozoa. vesicles. Sec Vesicul^-. Se;»iinales. Scmi spinalis dorsi muscle*, i. 372. Se7n2-tendi7iosus muscle, ii. 264 ; iv. 61 ; s. 137. nerve for, iv. 767. Sc7niiic, or Syro- Arabian, group of languages, iv. 1347. characters of the Semitic nations, iv. 1347. coniplexion of the, iv. 1333. See Varieties of Mankind. Sc77inocebus, a genus of Quadrumana, iv. 215, ct scq. See Quaprumana. characters of the genus, iv. 215. Sc7nnopithecus, a genus of Quadrumana, iv. 195, ct seq. See Quadrumana. characters of the genus, iv. 195. Scmnopiihccus, digestive organs of the, s. 304. Senegal, characters of the inhabitants of, iv. 1352, 1353. 856 GENERAL INDEX. Sensation, i. M4 ; iii. 723 A ; iv. 508. definition, iv. .'jOS. cause of, iii. 720 K. common and special sensations, iv. 509. objective and subjective sensations, iv. 510. refiex sensations, iv. 510. the optic thalami the centre of, iii. 722 M, 723 E. probable modus operand! 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. 7^2. in Annelida, i. 1G7. Sensrs, 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 II. plant, iv. 679. Sensorium, iv. 677, et scq. See Sleep. Sensorhan commune of Prochaska, iii. 720 K ; 722 A. its functions and seat, iii. 721 E. Sepia, the Italian pigment so called, i. 536. liexapodia, electricity of the, ii. 82. Sepiudee^ or cuttle-fishes, i. 521. characters of the family, i. 521. ova of the Sepia, s. [10.>], [106J. fossil shells of the, i. 520. Sepimn, or cuttle-bone, of cuttle-fish, i. 531. 546. Septa aponeurotic, i. 217. oftlie urinary bladder, i. 390. Septum nasi artery, i. 487. Septual branches of olfactory nerve, iii. 732. Septiwj, antero-posterior vertical, of the ciiest, iv. 1, ccrvico-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. transversum, ii. 2. 538. vcntriculorum, ii. 584. thickness of the, ii. 584. abnormal conditions of the, ii. 632. Sequcstrtiyn, or dead bone, i, 455, 456. Senform, or Indo-Chinese, group of languages, iv. 1347. characters of the Seriform nations, iv. 1350. Seroliny method of determining the presence of, in organic substances, iii. 798. In the composition of the blood, i.'4ll. Serous cavities, calcareous deposits in the, iv. 90. Serous and Synovial Me.mbuanes, iv. 511 . organisation of, i. 51. elasticity of, ii. 60. white and yellow fibrous tissue, iv. 512. areolar tissue, iv. 513, 514. bursa?, iv. 513. subcutaneous bursa?, iv. 514. covering of the internal surface by acell-growth, iv. 514. character of the cells, iv. 515. arrangement of the cells, iv. 515. subtendinous bursa?, iv. 516. cartilage corpuscles, iv. 517. synovial membranes, i. 251 ; 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.-25l. secretion of the unguen articulare, i. 253. serous membranes, iv, 522. description of these membranes, iv. 523. basement membrane, iv. 523. areolar tissue, iv. .324. 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, 52cS. morbid anatomy of serous and synovial membrane*, iv. 530 serous or dropsical effusions, iv. 530. physical and chemical i)ropcrtics, iv. 531. Serous anmi Synovial Membranes — 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 ii. 77. ’ loose cartilages, iv. 538. Serous membrane of the abdomen. Sec Peritoneum. or peritoneal, laminfe of the bladder, i. 380. adventitious serous tissue, iv. 140. SerpcntidcCy a family of Reptilia, iv. 26.5, ct scq, SerpentSy 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 dentatmn iii. 645. ' office of the, iii. 646. Sen’ofus inagnus muscle, i. 5. 361 ; iv. 755. magnus anticus muscle, iv. 576. minor anticus muscle, 1. 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. lumiuousness of, iii. 198. Scriularidce, a family of Polyj)ifera, 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. 460. 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 sesamoid 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. Set(S of animalcules, iv. 6. Seventh Pair of Nerves, iv. 543. origin, iii. 684. connexions, iii. 6S4. facial and auditory nerves, iv. 543. auditory nerve, iii. 684; iv. 543. its apparent origin, iv. 543. course, iv. 541. facial nerve, or portio dura of theseventh pair, iii. 6S4 ; iv. 544. description, iv. 544. course, iv. 545. in the cranium, iv. 545. ])ortio intermedia, iv. 545. in the temjjoral bone, iv. 545. connexion with the superficial petrosal nerve, iv. 54^. brancli from the facial to the membrane which close.s the fenestra ovalis, iv. 546. filament to the stai>edius muscle, iv. 546. chorda tympani, iv. 546. its connexion with the facial, iv. 546. connexion of the facial and vagus nerves, iv, 516. course external to the cranium, iv, 546. 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 scventli nerve, iv. 543. in the human subject, iv. 548. GENERAL INDEX. 857 Seventh Pair of Nerves — continued, general results of examinations in comparative anatomy, iv. 550. physiology 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. 553. 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. 554. Sexes, structural differences ofthe, 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 Gener.ationj Ovary; Ovum; Uterus and ITS Appendages. Sexual desire, ii. 443. 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 Hermaphroditism. reproduction, ii. 434. See Generation ; Ovum. Sharks, iii. 963, et seq., 981. Sheath, arterial, i. 221. brachial, anterior, i, 217. posterior, i. 217. femoral, ii. 237 240. Sheep, anatomy of the, s. 508. cranium of, s. 512. 5J4, 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. 362. analysis of, iii. 362. Shelahs, or mountaineers of Southern IMorocco, characters ofthe, iv. 1357. Shell, iv. 556. definition, iv. 556. general observations, iv. 557. shells of Mollusca, iv. 557. Echinodermata, iv. 555. Crustacea, iv, 569- periodical exuviation of the shell in Crus- tacea, iv. 571. shell-substance, membranous, of Dr. Carpenter, s. 489. Shclh of Cephalopoda, i. 543. of Gasteropoda, ii. 379, et seq. See Gasteropoda. of Tunicata, iv. 1193. design in the formation of shells, iii. 414. Shin, or crest of tibia, iii. 45. Shoulder-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. Shoulder-joint (abnormal conditions ofthe), 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. sim))le 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. Supp, Shoulder-joint — continued, chronic rheumatic arthritis of the shoulder-joint iv. 584. symptoms, iv. 584. diagnosis, iv, 585. anatomical characters, iv. 585. bones, iv. 586. cases, iv. 589, et seq. cases of partial luxation which have been pub- lished as the result of accident, but which are 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. 6(K). C. Fractures of the neck of the scapula, iv. 601. diagnosis, iv. 601. D. Fracture of the superior extremity of the humerus, iv. 601. J. intra-capsular fracture of the humerus, iv. 601. dissection, iv. 602. 2. extra-capsular fracture through the tu- 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 epiphysis 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, 615. 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, iv. 618. case, iv. 618. anatomical examination of the joint, iv. 619. congenital malformation of the shoulder-joint, wiih displacement of the head of the humerus on the dorsum of the scapula, iv. 619. case, iv. 620. Shrews, pelvis of, s. 164. Shrimps, muscles of, iii. 540. mode of progression of. iii. 436. Siah-Posh, a tribe of Northern India, physical characteris- tics of, iv. 1336. Sioinnng. anatomy of the, iv. 199, et seq. Siamese Twins, ii- 317 ; iv. 970. portrait of one of them, iv. 1323. Sid7iijum, a genus of Tunicata, iv. 1190, et seq. 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. 3189, et seq, characters of the genus, iv. 1189. Sigillina australis, iv. 1190. 3 K 858 GENERAL INDEX. Sigmoid cavity, great, ii. G6. 1G2. lesser, ii. 66. of tlie ulna, iv. 2f?9. flexure, s. 362. 365. use of, s. 366. notch, ii. 214. valves, ii. 58J. of arteries, i. 223. i’/V/.'-vesscls, or salivary glands, of the larva? of insects, ii. hysiology of liie sixth nerve, iv. 622. comparative anaiomy, iv. 622. paralysis of the nerve from disease in the neighbour- hood, iv. 622. SizCy in the organic and inorganic worlds compared, i. 118. SknfeSy muscles of llie, iii. 543. Skeleto.v, i. 141 ; iii. 821; iv. 622. definition, iv. G‘-2. Skeleton — continued. \ endo-skeleton, iii. 823. See Osseous System. \\\ skeleton of a crocodile, iii. 822. |m oxo-skeleton, iii 844 See Osseous System. law of unity in variety, iv. 622. j| Prop. I . VertebrjB are unequal quantities, iv. 624. ' [' II. even the one vertebra is not of equal quan- j. tity in all individuals of the same species, iv.625. III. all vertebra? contain a greater or less 14 amount of known elemental pieces, iv. ' , 625. : IV. the dorsal vertebra of human anatomy is an | i artificial figure, iv. 62c>. P V. the cervical vertebra developes the costal !| aj>pendages also. iv. 626. j VI. all the cervical vertebree develope costal appendages, iv. 627, VII. the lumbar vertebra developes the costal I' appendage, iv. 627. ji VIII. all the lumbar vertebrse develope costal j appendages, iv. 628, IX. the sacral vertebra? develope costal appen- ; dages, iv. 628. ii X. the coccygeal vertebrae are deprived of their ! costal a|)pendagcs, iv. 629. XI. the first seven thoracic costo-vertcbral figures are whole or plus quantities, iv. 629. XII, the five asternal costo-vertebral forms are j' proportionals metamorphosed from five sternal costo-vertebral plus quantities, iv. j 630. I XIII. the five lumbar vertebree are proportionals ! metamorphosed from five sternal costo- j vertebral archetypes, iv. 630. '■ XIV. the sacro-coccygeal series of vertebr$ are | proportionals degraded from sternal costo-vertebral circles, iv. 631. XV. the seven cervical vertebra? are proper- tionals degraded from seven stenio-coslo- vertebral whole quantities, iv. 631. XVI. the mammalian spinal axis consists of a series of segmental quantities, whose only |. variety or specific ^distinction dej>ends upon proportioning from whole thoracic quantities, iv. 631. ' XVII. uniformity of structure is a condition proper jl to the plus thoracic originals of the jj] .spinal axis of the mammalian body, iv. 632. ; XVIII. every spinal segment which is lesser refers , to every spinal segment which is greater ; J' and all lesser segments refer to that '' which is greatest, iv. 633. | XIX. structural uniformity cannot characterise j such spinal segments as are proportionally :[j or quantitatively various, iv. 633. jl XX. specific variety is none other than propor- |j tional variety, iv. 633. ' XXI. the knowledge of the differential quantity ; between all spinal segments, renders 1: them exactly uniform in idea, iv. 633. 'i XXII. without knowing the full dimensions of j] whole or uniform quantities, we can jl never rightly understand tlie real charac* Ij ter of lesser and special forms, and there- fore can never otherwise understand the ' law of formation, iv, 634. XX II I. the mammalian cervix is not limited to the fixed number of seven cervical vertebra?, iv. G34. ' XXIV. the number of cervical vertebrae in the ■ mammal cervix depends upon the num- I; her of archetypal costo-vertcbral figures whicii have suffered metamorphosis, iv, 635. I XXV. the presence of cervical ribs subtracts from the number of cei vical vertebra?, and adds !, to the number of thoracic archetypes, iv. j; 636. S XXVI. the length of the thorax depends upon the number of persistent costo-vertcbral 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 series 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 vertebrated animals are only as GENERAL INDEX. 859 Skeleton — coniimicd. the variable proportionals of sterno- costo-vertebral archetypes, iv. 638. XXXII. the hyoid 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. 644. XXXV. marsupial bones, pubic and ischiadic bones and ribs, are identical parts of the costo- vertebral whole quantities or archetypes, iv. 618. 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. 651. 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 sterno-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. XLIl. the sterno-costo-vertebral quantity is a pro- portional of the dorso-ventral quantity, iv. 667. XLIII. the scapulary and pelvic j^airs of limbs are proportional quantities metamorphosed frri7-niHxilIary nerve, iv. 548. 5tt/irrt-orbicular nerves, iv. 547. 522/?r£i-»)rbital artery, i. 491. 748 j iii. 93. 7S6. nerve, i. 748 ; iii. 784. vein, iv. 1404. 5wjD;'fl-orbitar cerebral convolution, iii. 096. 6’w/jra-orbitary foramen, i. 729. 6'w/;ra-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 Vertebrata, 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 difierent 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’es, glandular succenturiatte, 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. 8G8 GENERAL INDEX. i9//;)r^-rGnal vein, iv. 833. 1-113. iSw/>?Yj:-scapnlar artery, iv. 135, 8*24. branches, iv. 435. origin and relations, iv. 8*24. nerve, iv, 431. 755. iSw/)?'c-spinal artery, iv- 435. .S'w;?ra-spinata fossa, il. 157. 6’w/5rfl:-spinntus muscle, iv. 434. Si/;j7*«-spinous ligaments, s. I2I. iS'7/;;7Yi-trochcator nerve, i. 748. \o^y ^ 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. integumetit of the Vertebra^’a, s. 495. conversionary horny organs, s. 495. structure of hairs, spines, and feathers, s. 496. composition of the shaft of a liair, s. 49G. cuticle, s. 496. cortical tissue, s. 49G. medullary substance, s. 497. hair sac, s. 497. outer root-sheath, s. 497. fenestrated inner root-sheath, s. 497. imiierforate root-sheath, s. 497. spines and feathers, s. 498. the sliaft, s. 498. the quill, s. 499. tegumentary glands, s. 499. sud(»riparous glands, s. 500. scales of fishes, s. 501. structure of the enderon, s. 502. pigment of the enderon, s 502. papilla? of the enderon, s. 503. sensory appendages of tlie enderon, s. 503. the corpnscula tactus, s. 5( 3. Panician bodies [see also the article Panician Rodies], s. 504. muscles of the enderon, s. 505. calcareous deposits in tlie enderon, s. 506, muscles used in the legumentary system, iii. 543. Tegumentary organs of Edentata, ii. 54. See Edentata. of Insectivora, ii. 1004. See Insectivora. Keplilia, iv. 324. Amphibia, i. 102. Rirds, \. 3»9. See Avfs. Fishe.s, iii. 968. Insects, ii. 993. See Insects. of the Arachnida, i. 201 . Crustacea, i. 752. Gasteropoda, ii. 379. See Gasteropoda. Fchinodermala, ii, 31. ICntozoa, ii. 125. Tunicata, iv. 1 103. Uotifei’a, iv. 409, Tegumentary system of tongue, iv. 1 135. cutis, iv. 1 135. basement membrane, iv. 1135. epii helium, iv. 1 135. papillary structure of the tongue, iv. 1136. different papilla, iv. 1136 — 1139. structure, iv. 1 139. functions, iv. 1 140. Tela 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, iv. 935. sanguine temperament, iv. 936. melancholic, iv. 936. phlegmatic and choleric, iv. 933. nervous temperament, iv. 936. Tcyjiperature of the air, effect of, in producing hibernation, ii. 765. influence ofclimate 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. 'l\mporal 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. 731. fascia, i. 749. fossa, i. 727. 729. 734. 738. line, i. 729. 735. muscle, i. 729. 734. 749. nerve, deep, i. 719 ; iii. 787 ; iv. 547 branch of lachrymal nerve, ii. 283. external, ii. 281. 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. Tmporo-facial nerve, iii. 904. 2‘^w//joro-malar nerve, ii. 284 ; iii. 787. external temporal branch, ii. 284. malar branch, ii. 2S4. Temforo-Maxillary Articulation, iv. 937. ill human anatomy, iv, 937. bones, iv. 937. interarticular fibro-cartilage, iv. 937. synovial bursa?, iv. 937. ligaments, iv. 937. muscles, iv. 93H. motions of the joint, iv. 933. abnormal anatomy of the temporo-maxillary joint, iv. 938. accidents, iv. 938. dislocation of the condyle of the lower jaw, iv. 938. both condyles dislocated, iv. 938. one condyle only dislocated, iv. 939. congenital malformation, iv. 939. congenital luxation of the inferior maxilla, iv. 939. disease, iv. 939. chronic rheumatic arthritis, iv. 939. necrosis of the condyle of lower jaw of a scro- fulous boy, iv. 939. anchylosis, iv. 939. comparative anatomy, iv. 940. jn Mammalia, iv. 940. Aves, iv. 941. Roptilia. iv. 941. Pisces, iv 941. homology of the joh»t, iv. 941. TV’wporo-maxillary vein, iv. 1105. communicating branch from, iv. 1406. 7V///poro-parietal region, i. 749. Tewporu-zygomaiic, or internal, surface of malar bone, ii. 211. Tendinous cords, ii. .581. 583. 601. rings, arterial, ii. 587. auriculo- 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. 5H7. Tt’wdu Achillis, i. 1.50; iii. 139. rupture of, iii. 132. division of the, in cases of club-foot, iii. 132. oculi, 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. Tenebrionidec, or meal-beetles, ii. 163. Tensor membrancE tympani muscle, i. 734. palati muscle, i. 727 ; iii. 951. relations and action, id. 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'nge femoris muscle, ii. 264 ; s. 137. TenfflcZcs, brachial, labial, and ophthalmic, of Cephalopoda, i. 526. See CephalopuDa. Tentacula of Pteropoda, iv. 174, 175. TenthredOy or saw-lly, migration of, iii, 16. Tentorium cerebelli, i. 728. 732, 733; iii. 620. 673.687. partial deficiency of the tentorium, iii. 713. Teratology, iv. 942. definition, iv. 942. 1. original malformation of the germ, iv. 942. a. ascribable to the mother, iv. 942. 5. to the father, iv. 912. IT. deformify of the originally well-formed germ, iv. 942. 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 foetus, iv 943. 4. impeded development of the foetus by some remote and unknown cause, iv. 944. Malformations of the Ovum. iv. 916. 1. mola botryoides or h\ datica, — hydrometra aqua- lica, iv. 94G. 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. 948. 8. persistence of the umbilical vesicle, iv, 948. 9. constriction of the umbilical cord, iv. 948, 10. the umbilical cord too thick, iv. 948. IMalfomiatlons of the Feetns, iv. 948- A, Monstrosities produced by an Arrest of deve- lopment, iv. 948. I. Non-closure of the anterior part of the body, iv. 948. 1 . fissure of the whole anterior wall of the body, iv. 948. complete ectopia ofthe 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. b. congenital umbilical hernia, iv. 950. c. congenital ventral hernia, iv. 950. d. 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 vesicse urinarice, iv. 952. d. inversio vesic® urinaria?, iv. 952. 5. cervical fissure (fistula colli congenita), iv, 953. C. fissure of (he fnee, iv. 953. a. complete fissure of the face, iv. 953. h. 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, — acrania, iv. 954. fifit type: want of the brain and expo- sure of the whole basis of the skull, iv. 954. second type: the denuded surface of the basis craiiii occupied by a spongy sub- stance instead of brain, iv. 9-55. 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 foetus without a head, iv. 958. first type: acephali in the form of a rounded mass, without any indication of extremities, iv. 960. second type: acephali in the form of a rounded mass, with indication of feet, iv. 960. third type: acephali in which the trunk is more developed, without a head and thoracic or superior extremities, but composed of an incomplete trunk with an imperfect inferior extremity, iv. 961. fourth type: acephali in which the trunk is more developed, without a thorax and without superior limbs, and composed of an abdomen, genital organs, and two inferioi limbs, iv. 961. fifth type: acephali in which the trunk is much more developed, with an im- perfect thorax, composed of some dorsal vertebr® and limbs,— the superior limbs wanting, iv. 961. sixth type: acephali with a trunk com- posed of a thorax and an abdomen, and with two superior and two inferior limbs, iv. 962. seventh type: acephali in which some cranial bones are found, iv. 962. eighth type : body and extremities per- fectly well developed, and having a neck, which is Avanting in the other types, — the neck surmounted and ter- minated by the < ars, iv. 962. ninth type: acephali which are com- posed of the trunk only, without the lea^t indication of superior or inferior limbs, iv. 962. 872 GENERAL INDEX. Teuatoi.ogy, rrjalformations of foetus — continued. VI. Want, and defective formation, of the trunk, — Acormia, iv. 963. a. only a part of head formed, iv, 963. b. superior parts of the body formed with- out the inferior limbs, iv. 964. c. monopodia, iv. 964, d~ sympodia, iv. 964. e. original defective formation of the pelvis, iv. 965. /. defective development of the spinal column, iv. 965. VII. Defective formation of the extremities, iv. 965. 1. want of all the extremities, iv. 965. 2. want of the intermediate parts in the extremities, so tliat 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 fingers and toes, iv. 966. 6. coalesced fingers and toes, iv. 966. 7. abnormal direction of the foot. See Foot, Abnokmal 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. lilontrosiiies produced by Excess of develop- ment, iv. 967. I. Foetus in feetu, iv. 967. 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. h. in the abdomen, iv. 967. c. in the anterior mediastinum, iv. 968. d. in tile scrotum and testes, iv. 968. c. in the stomach, iv. 968. /. in the intestinal canal, iv. 968. g. in the orbit, iv. 968. k. 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 bv the external integuments, iv. 968. a. to the cheek, iv. 968. b. to the neck, iv. 968. c. to tlie 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 Jess perfect, and the other merely an appendix to it, — heter- adelphi, iv, 96S. first sjiecies : 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: the 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 du{)licity, iv. 972. 5. superior duplicity, iv. 972. generalisations, iv. 972 — 976. hermaphrodism in double monsters, ii. 736. Instinct guiding the formation of its habitation, iii. 9. Terehrantia, a section of Hymenoptera, ii, 86"», 866. characters and habits of the section, ii. 805. Teres ligament of the hip-joint, i. 13. 251. major muscle, i, 217. 360. 362 ; iv. 436. minor muscle, i. 217 ; iv. 436. Terctes lacerti, ii. 581* Termites, or white ants, ii. 865. See also Anis.^ white. Termitiuay a section of Neuroptera, ii. 865. characters of tlie section, ii. 865. Terrestria, a section of Hemiptern, ii. 86S, Test, or shell, of Tunicata, iv. 1193. TestaceUf characters of the family, i. 521. Testes (of brain), iii. 677. 685. 'I'ESTiCLE, 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. 498 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. 9H0. 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 foetal 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 feetus, and its passage into the scrotum, iv. 982. VI. functions of the testicle, iv. 984. influence ol the brain and testicles upon each other, iv. 985. 994. influence of tlie, in developing the general sexual peculiarities of the male, ii. 714, et seq. the testicles the only source of the fecundating power, ii. 458. quantity of semen emitted from the testicles at each coitus, iv. 1434, 1435. envelopes of the testicle, iv. 986. superficial or external spermatic fascia, iv. 986. cremaster muscle, iv. 986. deep spermatic fascia, iv. 986. spermatic 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. 9H7. origin of these defects, iv. 988. influence of these deficiencies and imper- feciions 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 Hermaphro- ditism. 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. 990 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. 999. encysted hydrocele of the spermatic cord, iv. 1000. complications of hydrocele, iv. 1001. hsematocele of the testicle, iv. 1002. encysted haematocele 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, iv. 1000. encephaloid cancer, iv. 1009. colloid cancer, iv. 1010. melanosis, iv. 1010. cystic disease of the testicle, iv. 1010. rssific deposits in the testicle, iv. 1011. loose bodies in the cavity of the tunica vaginalis, iv. 1011. foetal remains in the testicle, iv. 1011. varicocele, iv. lOll. scrotum, morbid anatomy of the, iv. 1013. elephantiasis, iv. 1013. hypertrophy of the scrotum, iv. 1014. cancer scroti, or chimney-sweeper’s cancer, iv. 1014. carcinoma scroti, iv. 1015. melanosis scroti, iv. 1016. fibrous tumours of scrotum, iv. 1017. See also Generation, Organs of. Tesiudince^ a family of Reptilia. iv. 265, et $eq, Testudo elephantopus, organs and mode of progression of the, iii. 450. mydas (turtle), nervous system of the, iii. G20. Tetanies, fatal, appearances presented by ruptured muscle in, iii. 526. 529. Tethea cranium, a species of Porifera, iv. 66, 67. lyncurium, a species of Porifera, iv. 66. Telhium, a family of Porifera, iv. 65. characters of the family, iv. 65. propagation of, iv. 70. Tetrabranchiata, i. 518. descri])tion of the order, i. 518, Tetraodon electricus, ii. 81. localities inhabited by the fish, ii. 82. physiological effects of its electrical discharge, il. 84. Tetraodons, teeth of, iii. 980. mode of progression of the, iii. 437. Tetrarhynchus, mode of reproduction of, s. 27* Tetrnspore of red Alg$, or Florideae, s 221. Tetrodon mola (moon-fish), nervous system of the, iii. 615. Teuthidee, calamaries, i. 521, characters of the class, i. 521. Textus cellularis intermedins v. laxus, v. 510. strictus, i. 510. stripatus, 1. 510. Thalamiy 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. Thallns of Lichens, origin of the, s. 227. Thebi'sius, foramina of, ii. 580. valve of, or lesser Eustachian valve, ii. 580 j iv, 1415. veins of, or venje miuimae, ii. 597 ; iv. Mlo. Theca or ascus of Fungi, s. 225. 230. Theca folliculi of Baer, s. 551. 555. Thenar eminence, ii. 358. Theodaclylus, organs and mode of progression of, iii. 449. Theorus, a genus of Rotifera, iv. 401. Theutidee, a famih' of Fishes, iii. 957. Thickening of mucous membrane of nose, Hi. 738. Thief, test for the discovery of a, in India, iv. 466. Thigh, superficial fascia of the, ii. 238. Thigh-bone, W. 165. See FVww?*. Third nerve, iii. 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 of death by, s. 387. Thoracic aorta, i. 189. See Aorta. aneurism of the, i. 192. artery, iv. 818. duct, iii. 206. 579 ; iv. 816. detected by Eustaebius, 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 acromialis artery, i. 360. alaris artery, i. 358. 364. humeraria artery, i. 359. longior artery, i. 359.361 ; iii. 249. suprerna artery, i, 3*>9, 360. 364. Supp. TAoroczVo-cervical 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. 1021. 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 (mediastinal or cardiac), iv. 10^2. borders of the sternum, iv. 1023. 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 ihe sternum, iv. 1024. ossification of the appendix, iv. 1024, ribs, iv. 102 1. 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, postfiior extremity, iv. 1030, of the head, iv, 1030. neck, iv. 1030. tubercle, iv. 1031. angle, iv. 1031. groove (specific ditferences), 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 vertebra, iv. 1032. with the transverse processes of two vertebra, iv. 1032. a. the posterior costo-trans- verse ligament, iv. 1032. b. the middle or inter-osseous costo-trans verse liga- ment, iv. 1032. c. the anterior or long costo- transverse ligament, iv. 1032. diameters peculiar to certain costo-vertebral articulations, iv. 1032. with the sternum (chondro-sternal articulation), iv. 1032. connexions of the ribs with tlieir cartilages, iv. 1033. articulations of the costal cartilages one with the other, iv. 1033 ligaments of the sternum, iv. 1033. 3 L 874 GENEllAL INDEX. Thorax — cn-nUnued. ol' the tliorax in general, iv. 1033. boundaries ot the thoracic cavity, iv. 1034. contents of the tliorax, 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. 103G. anterior region, iv. 1030. posterior region, iv. 1037. lateral region, iv. 1037. base of thoracic cavity, iv. 1037. conformation as afiected 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. 8«8. lymphatics, iii. 229. of the respiratory muscles, iv. 1042. intercostal muscles, iv. 1042. external, iv. 1013. 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. Icvatorcs costaruin, iv- 1055. triangularis sterni (sterno-costalU), iv. 1055. action, iv. 105''. infra-costales, iv. 1056, action, iv. 10.56. of the elasticity of the ribs, iv. 10.56. of the clastic power of the lungs, iv. 1058. of respiratory muscular power, iv. lOGO. the hoemadynamometer, iv. 1000. 10G3. of the respiratory volumes, iv. 1064. of the volumes of air expelled from the lungs, iv. 10G6. vital capacity, iv. 333. 10G8. 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 weieht, iv. 1073. relation of vital capacity to the circumference of the thorax, iv. 1077. affected by age, iv. 1077. by disease, iv. 1078. of the respiratory movements, iv. I(i79. profile view of the breatiiing 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-syimnetrical breathing movements, iv. 1084. reversed breathing movements, 'iv. 1084. massive breathing movements, iv. H'84. i.iterrupted breaihing movements, iv. 1084. partial breathing movements, iv. 1084. quick and slow breatiiing movements, iv. 1085. irregular breathing, iv. 1085. double breathing, iv. 1085. of tile 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. 10®6. Thvrax^ congenital abnormal conditions, iv. 949. fissure of the thorax, iv. 949. ectopia cordis, iv, 949. Thn'pidce, a family of Insecta of the order Homoptera, ii. 8G8. Thrush, white inniguct French), iv. 118. Thumb, carpo-metacarpal articulations of the, ii. 509. abnormal conditions of the, ii. 511. Thunny, instincts of the, iii. 13. Thygroma, i. 469. ThylacinuSy a genus of Marsupialia, iii. 258. characters of the genus, iii. 258. species of, iii. 258. Thylacinus llarrisii, or “hy£ena” of Van Diemen’s Dand, iit. 258. Thijlacolherium, dental peciiliaiities of the, iii. 2G0. Thy77ius artery, iv. 822. 1094. vein. iv. 1094. 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. vasculcir 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. luberciilar disease, iv. 1102. scirrhus, iv. 1 102, atrophy, iv. 1102. hypertrophy, iv. 1102. a hypothetical cause of spasmodic croup, iii. 124. morbid conditions of the feetus in utero, ii. 331. T/^yro-arytenoid ligaments (chorda? vocales), iii. 102. 105; iv. 1479. inferior and superior, iii. 105. mtiscle, iii. 108. action, iii. 109. See also Voice. 7’//^?o-epiglottid muscles, iii. 110. ligament, iii. 104. Th7jroA\yo\o-pharyngeal nerve, ii. 497. 7'o72.vf/jf or amygdalae, iii. 952 ; iv. 1121. vessels and nerves of the tonsils, iii. 953. calculi of the, iv. 83. Tophiy or goiuy concretions, iv, 90. chemical constitution of, iv. 91. Torcular 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, 8«0. lircumstances under which the discharge of electricity takes place, ii. 82. exhaustion from a succession of discharges, ii. 83. localities inhabited by the lish, 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. prodnciion 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, 76-5. 768. 775. causes of, i. 416 ; ii. 768. 775. diflerences between torpor and hibernation, ii. 77-5, 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. 450. uses of its carapace and plastrum, iii. 450. land, urine of the, iv. 1281. mud. or trionyx, pelvis of the, s. 170. Torvla of the human subject, iv. 144, Torul- mucous fibroid; fibrous and muscular “ polypi,” s. 689. 4. pathological conditions of the mucous coat, s. 092. simple hypertrophy ; dysmenorrhccal 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. 693. simple inflammatory hypertrophy, with extroversion of the cervical mucous membrane (pseudo-ulcer), s. 693. catarrhal inflammation of the mucous coat of the uterus ; endometritis ; leucorrhoea, s. 694. ulceration of the raucous coat : erosion, abrasion, and excoriation, s. 694. distensions of the uterine cavity, s. 697. hydrometra, s. 697. hsematometra, s. 697. pljysometra ; 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. 698. pathological conditions involving several of the uterine tissues, s. 698. cancer, s. 699. caiicroul; epithelial cancer; cauliflower excrc 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. 90. softening and induration ot the, iv. 712. cystoides, iv. 151. mascuUnus. 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. tlie round or sub-pubic ligaments, s. 705. Vagina, s. 706. normal anatomy, s. 70G. dimensions, s. 706. external surface, s. 706. GENERAL INDEX, 883 Uterus and its Appendages, vagina — coniinu d. composition, s. 706. internal surface, s. 706. arteries; veins; lymphatics; nerves, s, 707. uses of the vagina, 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. External organs of generation, s. 708. normal anatomy, s. 708. the mons veneris, s. 708. labia, s. 708. clitoris, s. 709. nympliae, s. 710. vestibule, s. 710. vaginal orifice and hymen, s. 710. origin, varieties, and signification of the hymen, s.' 710. sebaceous and muciparous glands and follicles of the vniva ; vulvo-vaginal gland, s. 711. bulb of the vagina; pars intermedia; con- strictor vagina, 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. e dimensions and weight, s. 715. foetal surface ; amnion ; chorion ; fcetal blood- vessels, s. 715. uterine surface, s. 716. circumference, s. 716. substance, s. 717. tufts and villi, s. 717. termination of the fcetal vessels, s. 718. decidua, 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. Vtero-^cslatiun, varieties in respect to, and the develop- ment of the young, ii. 436. See Ovum. Vtero-vesical ligaments, s. 705. sacral ligaments, s. 705. Utricular glands or follicles of uterus, s. 036. Utriculus prostaticus, iv. 151. 1252. development of, iv, 15.3. See Vesicula Prostatica. Vvea^ or spherical choroid membrane, ii. 178. See Choroid coat, or iris. ii. 182. See Iris. flocculent growth of the, in the horse, iii. 95. Uvulay i. 385, 386 ; iii. 961. vesica?, iv, 147. V. Vacuum produced by the suckers of the feet of the house- fly, iii. 443. by limpets, iii. 44-5. Vagina, s. 706. normal anatomy, s. 706. dimensions, s. 706. external surface, s. 706. composition, s. 706. internal surface, 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 Hermaphroditism. calcareous accumulations in the vagina, iv. 86. Vagina vasorum, iv. 772. 788. Vaginal artery, ii. 831. branches of hepatic duct, iii. 169. artery, iii. 171. branches of portal vein, iii. 107. Vaginal — continued, bursJE, deep, i. 468. orifice, s. 710. hymen, s. 710, 71 1 . 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, i. 734. veins, iv. 1414. Vaginitis, s. 707. Vagus nerve, iv. 546. 815, 816. See Par vagum. Valgus, anatomical characters of, ii. 348, 349. Valley, or vallecula, of Haller, iii. 688. Valsalva^s sinuses of the aorta, i. 189. Valve, Eustachian, ii. 580. ileo-caecal or ileo-colic, s. 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, li. 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. 1H77. different forms of valves, iv. 1378. epithelium of valves, iv. 1379. fibrous lamina, iv. 1379. sinuses in the walls of veins, iv, 13S0. 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. 580. triglochis v. tricuspis, ii. 581. Valvula conniventes, s. 346. I'an Diemen's Land, the ‘‘ hytena ” 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. Varices of the anal veins, i. l85, 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, 1399. 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. 1399. hemorrhoids, iv. 1309. pathological conditions of varicose veins, iii. 129. varicose veins of the leg, causes 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 characteristii.s of man, iv. 1294. his two hands, iv. 1291. erect attitude, iv. 1295. cranium, iv. 1295. 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. 1297. form of the trunk, iv, 1297. visceral apparatus, iv. 1297. conformation of the brain, iv, 1299. 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. TIT. general survey of the diversities, in physical and psychical characteis, presented by different races of mankind, iv. 1315. GENERAL INDEX, 881 Varieties of Mankind, general survey ^continued. aiialomical difierences by which the several races of mankind are distinguished from each other, iv. 1319, 1. conformation of the cranium, iv. 1319. prognathous type, iv. 1321. pyramidal type, iv. 1322. oval or ellipticMl 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. 133.'’. 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 clianged their mode of life, iv. 133d. 5. colour, texture, and mode of growth of the hair, iv. 1337. pliysiological conformity or diversity of the several races, iv. 1339. average duration oflife, 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. 1311. duration of pregnancy, iv. 13(1. fertility of hybrid races, iv. 1311. psychical comparison of tlie various races of mankind, iv. 1342. philological evidence of a common origin, in language, iv. 1345. aptotic type, iv. 1346. agglutinate type, iv. J346. 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. 1318. European nations, iv. 1348. Asiatic nations, iv. 1318. African nations, iv. 1352. American nations, iv. 1358. Oceanic nations, iv. 1361. general recapitulation, iv, 1363. addendum on the causes of tlie tendency to extinction in the races of aborigines, iv. 1365. Vitrij-, aneurismal, i. 2ll. See Aneurism; Artery, Pathological conditions of. f 'di us, ii. 318. I'as deferens artery, iv 983. deficiencies and imperfections of the, iv. 987. ejaculatorium, iv. 147. f'asa brevia, i. 195 ; iv. 1414 ; s. 327. efferentia, iii. 208. 231. of epididymis, iv. 979. deferencia, i. 380 ; ii. 457, 458 ; iii. 922 ; iv. 1431. inferentia or afTerentia, iii. 207. 231. pampiniforinia, iv. 982. va'Orum, i. 223 ; iii. 233 ; iv. 1381. Vascular branch of nervus vagus, iii. 887. rami carotid, iii. 887. ramus ad divisionem arterise carotidis, iii. 887, rami vasculares posteriores et interni, id. 887, anteriores et interni, iii. 887. Vascular system. See Circulation. }’asculu7}i aberrans, iv. 980. V asco^ceUular structure of penis, iii. 913. Vastus externus muscle, iii. 44. interims, iii. 14. nerves for, iv, 763. Valeria Indica. tallow- like fat of the, i. .58. Vauchen'acecPy 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. 169. food, s. 389. 393. See Food. nuclei of intestinal calculi, iv. 84. parasites, iv. 143. VegctableSy compared with animals, i. 124, cellular tissue, i. 125. chemical composition, i. 121. immediate principles, i. 125. acids, i. 125. oxides, i. 125. circulation, i. 133. digestion, i. 132. electricity, i. 137. forms, i. 124. ln'at, i. 136. hibernation of plants, iii. 157. injurious eflects of forcing a new crop in an un- naturally short interval, iii. 107. light, i. 136. motion, i. 139. nutrition, i. 130. Vegetables — continued. organic composition, i. 135. reproduction, i. 129. See Reproduction, Vege- table. respiration, i. 132 ; iv. 328. secretion, i. 135. sensation, i. 139. size, i. 124. symmetry of plants, iv. 852. tubular or vascular tissue, i. 125. vital manifestations, i. 127, ultimate elements of vegetables, ii. 12. substances used as food, ii. 13. on the relation which exists between the animal and vegetable kingdoms, as regards the funciion of re- production, s. 256. Vein, iv. 1367. literary lustory, iv. 1367. I. structure, iv. 1368. epithelium, iv. 1369. fenestrated membrane, iv. 1369. internal tunic of longitudinal fibres, iv. 1371. middle coat of intermixed circular and longitudinal fibres, iv. 1372. external coat of longitudinal fibres, iv. 1373. minute veins, iv. 1373, regions in which the veins undergo striking modi, fications in structure, iv. 1375. veins at their junction with the heart, iv. 1375. cavae, passing through the diaphragm and jio- l icardium, iv. 1376. cerebral sinuses, iv. 1376. umbilical vein, iv. 1376. venous valves, iv. 1377. structure of valves, iv. 1379. fibrous lamina, iv. 1379. sinuses in the walls of the veins, iv. 1380, office of valves, iv. 1381. vasa vasorum, iv. 1381. nerves of veins, iv. 1382. comparative structure, iv. 1382. caudal venous heart of eel, iv. 1383. II. physical and vital properties, iv. 1384. vital contractility, iv. 1384. venous tonicity, iv. 1385. III. general remarks upon veins: origin, course, anasto- moses, plexuses, &c., iv. 1385. origin of veins, iv. 1386. course, anastomoses, plexuses, &c., iv. 1386. IV. function of veins, iv. 1389. circulation in the veins, iv. 1389. as diverticula and reservoirs of blood, iv. 1389. venous absorption, i. 24; iv. 1390. V. development of veins, iv. 1390. as capillaries, iv. 1390. morbid anatomy of veins, iv. 1391. phlebitis, iv. 1392. plastic phlebitis, iv. 1392. suppurative phlebitis, iv. 1394. obliteration of veins, iv. 1395, healing of wounds in veins, iv. 1305. effects of ligatures on veins, iv. 1396, phlebectesis ; varix, iv. 1397. varices of the leg, iv. 1398. varicocele, iv. 1399. haemorrhoids, iv. 1399. rupture or perforation of veins, iv. 1399. alFections of the valves of veins, iv. HuO. pblebolites, iv. 1400. calcareous degeneration of veins, iv. 1402. fatty tumours, iv. 1402. entozoa in veins, iv. 1402. calcareous deposits in the coats of veins, iv. 89. 1. parietal, iv. 89, 2. central, iv. 89. intra-venous air, secretion of, iv. 145. adventitious formations in the, iv. 102. Vein-stones, or phlebolites, iv. 1400. I'cms in particular ; — abdominal, i. 15. alar, iv. 1407. alveolar, Iv. 1404. angular, iv. 1404. of ankle, i. 150. ar'icLilar, iv. 1411. auricular post*-rior, iii, 903. axillary, i. 360; iii. 249; iv. 1407. azygos, i. 365; iv. 1381. 1404. I4e9. dorsal, i. 368. major, i. 365; iv. 1409. minor, or semi-azygos, i. 365 ; iv. 1409. superior, i. 366. left, iv. 1409. basilic, i. 216. 360; ii. 63.361.302; iv.1407. median, iv. 1407. b isi-vertebral of Breschet, iii. 630. of brain, iil. 704. of bones, i. 436. brachio-cephalic, ii. 851 ; iv. I lOS. of brain, iii. 704. bronchial, i. 366; iv. 1 109. GENERAL INDEX. 885 ydns — continued, buccal, iv. 1404. cardiac, great, iv. 1414. posterior, iv. 1414. cephalic, i. 210. 359, 3G0 ; ii. 03 ; iii. 249 ; iv. 1407. median, iv. 1407. cerebral, iv. 1382. ophthalmic, iii. 94. coronaria ventriculi, iv. 1414. coronary, great, ii. 596 ; iv. 1404. 1414. smaller posterior, ii. 597 ; iv. 1415. anterior, ii. 597 of clitoris, s. 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 ren;il, iv. 236. 238. epigastric, superficial, iv, 1411, 1412, deep, iv. 1412. epiploic, iv. 1414. from evelids, 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, 6i*3. femoral, superficial, ii. 238 j 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. 32-5. gastro-epiploic, right, s. 327 . 381. left, s. 327. gluteal, iv. 1412. hsemorrhoidal, 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. 1 108. intercostal, i. 365 ; iv. 1409. left superior, iv. 1409. interlobular, iii. 167. 173; iv. 1414. interosseal, palmar, iv. 1407. intestinal, s. 3^0. iutra-lobular, iv. 1414. jugular, anterior, i. 732 ; iii. 571. 579. internal, iv. 815, 816. 1406. external, ii. 227 ; iii. 571. 903 ; iv. 1105. of knee-joint, iii. 48. laryngeal, iv. 1406. of leg, iii. 128. lingual, iv. 1406. lobular, iii. 1G8. lumbar, iv. 14)3. mammary, iii. 246. 249; iv. 823. 1408. masseteric, iv. 1404. maxillary, iii. 903. 949; iv. 1405. median, ii. 63. 362. 524. basilic, ii. 23. 361, 382. cephalic, ii. 64, 361, 362. of membranous 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. cesophageal, s. 326. ophthalmic, ii. 228 ; iii. 786. cerebral, iii. 94. facial, iii. 94. ovarian, iv. 1413. palatine, iv, 1414. palpebral, iv. 1414. paticreatic, iv. 1414 ; s. 86. pancreatico-iluodenal, s. 381. of parotid region, iii. 903. Veins — continued. of penis, iii. 917 ; iv. 1254. dorsal, iii. 933; iv. 1254. of perineum, iii. 933. pharyngeal, iii. 949 ; iv. 1406. phrenic, iv. 1413. planiar, ii. 355. deep, internal, iv. 1411. external, iv. 141 1. popliteal, i. 242 ; iii. 128 ; iv. 1411. portal, iii. 167 ; iv. 2.50, 1332. 1414 ; s. 381. primitive, right, ii. 828. profunda, iv. 1412. pterygoid, iv. 1405. pubic, superficial, iv. 1411. pudic, iv. 1412 ; s, 714. pulmonary, ii. 581, 582; s. 274. pyloric, superior, s. 327. 381. rachidian, iv. 1401. 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. 14u9. 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, iv.l41 1 . posterior, or external, iv. 1411, major, ii. 351 ; iii. 128. 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. splenic, iv. 788. 1414 ; s. 381. stomach, s. 325. subclavian, iii. 578. 817 ; iv. 815. 1407. subcutaneous of elbow, ii. 63. sublobular, iii. 173; iv. 1414, submental, iv. 1404. subscapular, iv. 1407. superficial, of neck, iii. 571. of supra-renal capsules, Iv. 833. supra-orbital, iv. 1404. sural, iv. Mil. temporal, iii. 903 ; iv. 1405. deep, iv. 1405. temporo-maxillary, iv. 1405. communicating branch from, the, iv. M05. of Thebesius, or vence minima, ii, 527 ; iv. 1415. thoracic, iv. 1407. thyroid, iv. M07. inferior, ii. 851 ; iv. 1408. superior, iv. M06. middle, iv. 1406. tibial, iv. 1411. transverse, iv. 1 107. facial, ii. 127 ; iii. 933. ulnar, ii. 63 ; iv. 1407. umbilical, iii. 936 ; iv, 1374. of urethra, iv. 1254. in female, iv. 12C4. 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. of villi of intestine, s. 352. Velelln limbosa, mode of progression of the, iii. 433. Velocity, in insects and birds. See Motion, Animal. of the camel, iii, 4.54. of fishes, iii. 438. See Motion, Animal, of the hare, iii. 4.53, 4.54. of predaceous insects, iii. 443. of some species of Quadrumana, iii. 456. of sound. See Sound. Velum interposiium, iii. 635. 676. palati, iii. 95i. or trigone, of the bladder, i.385, posterior medullary, iii. 690. Vena alba thoracis of Eustachius, iii. 206. cava, i. 11 ; ii. 828. superior, U. ; iv. 1404. 1403. veins which form the, iv. 1404 — 1410. inferior, or vena cava ascendens, ii. 679, 580 : iv, 1411.1413. origin, course, and relations, iv. 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. 68G GENERAL INDEX. t\na cava — contmucd, anastomoses of vena cava and portal vein, iii. 17G. 178. fissjire for the. iii. 161. coronaria cordis minor, ii. 597. maxima cordis, ii. 59G. innominata. right, iv. 815, 81G. portce, s. 3*25. 327. 3H1. sulcus of, iii. IGl. prjeparata, or frontal vein, i. 748. salvatella, iv. 1407. saphena, i. l'>. 148; ii. 238. major, iii. 128. minor, iii. 128. Vents comites, i. 3G0 ; iv. 1407, ei srn. accompanying arterial vessels of muscles, iii . 51G. of br;ichial artery, i. 217. innominatre of Vieussens, ii. 507. magnae Galeni, iii. G31. G40. 705. miniinae. or veins of Thebesius, ii. 507 ; iv. 1415. Venereal disease, suppurating node a symptom of, i. 449. Vbnous 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. 1401. facial vein, iv. 1404. temporal vein, iv. 1105. superficial, iv. 1405. middle, iv, 140.\ internal maxilUiry, iv. 1405. occipital, iv. 1405. 2. veins of the neck, iv. 1405. jugular vein, external, iv. 1405. anterior, iv. 1405. internal, iv. 140G. collateral branches, iv. 140G. vertebral vein, iv. 1406. spinal veins, iv. 140G. 3. veiiis 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 (venlexus of the, iii. 691. fifth, iii. 674. 704. development, iii. 675. lateral, iii. 674. body of, iii. 671. 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, 658. See Heart (normal anatomy), of the larynx, iii. 112. of septum luciduin, iii. 674. development, iii. 675. Ventriculus o,merior, s. dexter, s. pulmonaFs, 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. Sqq Duodenum. J'enus decussata, ovarian ova of, s. [109]. Vcrclillum. ova of, s. [127]. Vermecelli marini, ii. 401. Vermes snetorii. See Entozoa ; Sterchnintha, teenlaeformes. See Entozoa ; Sterclmintha. tcretes. See Entozoa ; Sterelmintha, vesiculare.c. See En iozoa : Sterelmintha. unciati. See Entozoa ; Sterelmintha. Vermiform animals, mode of progression of, iii. 4.34, appendix, development of, s. 402, process, inferior, iii. 078, 689. superior, iii. 678. 688. Verrucarits, organs of rcpro7. 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. 541. vein, iv. 815. 822, 1406. 1408. Vei'tebrata, muscular system of, iii. 541. nervous system of, reviewed, iii. 614. Vertexy or bregma, i. 725. See CraniUiM. Vertigo, 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. Vesica natatoria of fishes, i. 376. urinaria, i. 376. See Bladder of Urine. Vesical arteries, ii. 830. , fascia, i. 388, plexus of nerves, s. 430. veins, i. 387 ; iv, 1412. Vesicle, germinal, of Purkinje, s. 70. [87]. [133]. Vesicles or follicles, Graafian, s. 56. [81]. [89], See Ovum. 7 V^fco-prostatic plexus of veins, iii. 933 : iv. 1412. /^ejjfco-uterine folds, iii. 943. Vesrcula spermatica spuria, iv. 151. development of, iv. 153. Vesicui.a Prostatjca, iv. 151. 1252. 141.5, definition, iv. 1415. development, iv. 153. I. anatomy, iv. 1415. Man, iv. 141.5. Quadrumana, iv. 1416 1428. Volitantia, iv. 1417. Insectivora, iv. 1417. Ferge, iv. 1417. 1428. Pinnipedia, iv, 1418. Marsupia’iia, iv. 1418. Rodentia, iv. 1418. Cavia cobaya, iv. 1418. Edentata, iv. 1419. Pachydermata, iv. 1419. Solidungula, iv. 1419. Kuminantia, iv. 1419. Cetacea, iv. 1421. II. physiology, iv. 1422. III. morphology, iv. 1423. addendum, iv. 1424. VesicuUe s. cellulse aerejB, s Malpighianas ; alveoli pulmo- num, Rossignol, s. 268. minute anatomy, s. 270. epithelium of the air-passages and cells, s. 270. elastic tissue of the air-cells, s. 272. Vesicul® 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, Vesicule copulatrice, i. 376, Vespa crabro, or hornet, ii. 865. Vespertilionidcs. Seg Cheiroptera. Vespertina, a section of the order Lepidoptera, ii. 867. characters of the section, ii, 807. Vespiiia*, or hornets and wasps, habits of, ii. 865. Vestibular artery, ii. 542. Vestibule 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, .558. office of the, in the function of hearing, ii. 567. 577. Vestibule, the. atrium vagina?, iv. 1420; s. 710. bulbus vestibuli, s. 712. abnormal anatomy of the vestibule, s. 714. Vestigium foraminis ovalis, ii. 580. Vibratory movements of membranous structures, theories of, iv. 1475. VibrionidcB, a family of Parasitic animals, ii. 113. organisation of the, ii, 113. VibrionidcE , a family of Polygastric animals, iv. 4. characters of the family, iv. 4. Vidian artery, i 490 ; ii. 556 ; iii. 733. canal, i. 727 ; ii. 287, 288. nerve, i. 727. vein, i. 727. nerve, ii. 287. sulcus, i. 733. Vkussenian valve, iii. 678. 086. C90. Villi of cervix uteri, s. 639. intestine, s. 350. epithelium of the villi, s. 351. basement membrane, s. 351. blood-vessels, s. 351. basis of the villus, s, 352. cyioblasts or nuclei, s. 352. lacteals of the villi, s. 352. muscular constituent of the villi, s. 353. changes in the villi during digestion, s. 355. abnormal conditions of the, s. 412. of the lacteals. i. 21, placental, s. 717. J'iiK'gar, or acetic acid, considered as an article of food, s. 395. Viuegar^eeh or Anguillula aceti, ii. 113. J’i7ious 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. 448. Vis insita of Haller, doctrine of the, iii. 519. in connexion with the vis nervosa, iii. 30. medicatrix naturge, 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. Viscache, anatomy of the, iv. 373, et scq. J'ision, phenomena of, Vision, iii. 337 ; iv. 1436. Dr. Buckiand 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, Iluyghens, and Young, iv. 1436. velocity of luminous undulations, or rapidity with wliich light travels, iv. 1436, 1437. white light, composition and proportion of, accord- ing to Newton and Fraunhofer, iv, 1437. colours of which the solar spectrum in reality consists, iv. 1437. calorific rays of Sir W. Herschel, iv. 1437. chemical rays of Dr. Wollaston, 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. Porterfield, 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. 14.52. hypothesis of single vision, of Newton and Wol- 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. 14.53. hereditary tendency, iv. 1453. influence of sex, iv. 1454. hypotheses, iv. 1454. congenital achromatopsy, iv. 1454. dichromatic Daltonism of Wartmann, iv. 1434. polychromatic Daltonism of Wartmann, iv. 14-55. list ot the most common confusions of colour, 1456. cases, iv. 1456. 1457, non-congenital achromatopsy, iv. 1457. pernianent, iv. 1457. temporary, iv. 14.58. causes of the affection, iv. 1460. remedial measures, iv. 1461. hyperchroraatopsv, iv, 1461. anortliopia, iv- 1462. 888 GENERAL INDEX, Vision — continiu'd, myopia, or near sight, iv. 1462. causes, iv. 1463. course of the affection, iv. 1464, treatment, iv. 1464, 1465, presbyopia, iv. 1465.* causes, iv. 1465. remedial measures, iv. 1466. spectacles for myopic and presbyopic vision, iv. 1466, 1467. cylindrical eye, iv. 1467. method of detecting the defect, iv, 146ft, 1469. Professor Stokes’s astigmatic lens, iv. 1468. treatment, iv. 1460. 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 N Envoi’s 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 countie.s, cities, towns, of town and country, and of the several dis- tricts of large cities, iv. 1471. used as a test of tlie 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 profession^, without refer- ence to their place of residence, iv. 1473. rate of mortality, iv. 1473. expectation of life, iv. 1474. mean duration of life, iv. 1474. probable duration of life, iv. 1474. VitalUyy dormant, or inactive, iii. 141. 151, dormant vitality of seeds, eggs, &c., iii. 155. length of lime 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 tlieir structure and composition, iii. 1 5r,. dormant vitality of plants 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. 159. suspension of vital action in parts of the human body, iii. 159. the “ Atomic theory ” of Dr. Daubeny quoted, iii. 1.59. Vitelline membrane, structure of, in various animals, s. [133]. [137]. chemical composition of, s. [141]. See Ovum. Vitcllas, 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. J'lvcrridcBy or palm-cats, dentition of the, iv. 911. Viviparous animals, i. 146. generation, ii. 424. Vocc (ii 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. 1475- vibratnrv movements of the vocal organs, iv. 1475. 14'76. experiments, 1477. vital state of the voeal ligaments, iv. 1480. influence of variations in the hygrometri*- and fher- 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. 1181. tlie 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. MSG. 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. llodentia, iv. 1491. Edentata, iv. 1492. Pachydermata, iv, 1492. Puminantia, iv. 1494. Cetacea, iv. 1494. Birds, iv. 1495. epiglottis, iv. 1495. rima glottidis, iv. M95. muscles, iv. 1496. larynx, superior and inferior, iv. 1496. bones of the inferior larynx, iv. 1496. membrana tyinpanifornus, iv. 1497. arytenoid cartilage, iv. 1497. trachea, iv. 1500. physiology of the voice of birds, iv. 1500. Reptilia, iv. 1501. Sauria, iv. 1502. Chelonia, iv. 1.502. Batrachia, iv. 1502. Ophidia, iv. 1502. Insecta, iv. 1503. buzzing or humming of insects, iv. 1504. vocal muscles in comparative anatomy, iii. 544. J'oleSy vsater, anatomy of the, iv. 370, et seq. Volitantia, Weberian organ in, iv. 1417. Vo^ion^ the corpora striata the centre of, iii. 722 L, 723 VolvocinidiVy 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. 2i3. structure, ii. 213. surfaces, ii. 213. 1. right, ii. 213. 2. left, ii. 213. Vomilinfi, act of, s. 316. causes, il. 26 ; s. 316, 317. inverted action of the oesophagus in, iii. 760. Vorticella convallaria, iv. 397. cyathina, iv. 7. microstoma, mode of reproduction of, s. ft. VorticellcBy 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. VorticellinidiS (bell animalcules), a family of Polygastric animals, iv. 4. characters of the family, iv. 4. Vulva, the, s. 708. J'ulvo-uterme canal, s. 706. See Vagina, /'24/y£>-vaginal glands, s. 712. W. Wading birds (Grallatores), characters of, i. 269. Walking power of man, iii. 459. tables of the measure of the inclination of the trunk in various modes of progression, iii. 460. estimate of forces employed in walking, iii. 461. principles upon which walking and running differ, iii. 471. Walrus {Trichechus rosmarus), dentition of the, iv. 916. irrrrw-hlooded animals, temperature of, as compared with cold-blooded animals. See Heat, Animal. Wart-hogs (Phacochcerus) of Africa, teeth of the, iv. 870. Warts on fingers, ii. 528. warty excrescences of the anus, i. 184. Wasps ( Vespidaj). 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 (Chrysididae), ii. 8GG. habits of, ii. 866. Waste of the organism of animals, s. 382. 385, GENERAL INDEX, 889 Water in the composition of the blood, i. 410. removed from living bodies by the skin, iv. 450. 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. 3M7. mode of aqueous action on the various organs, s. 387. quantiiy of water contained in the various kinds of food ordinarily made use of, s. 388. sound transmitted by, ii. 506. IValer-beetleSy ii. 860. characters of, ii. 8G0. Waier-bra^ky or pyrosis, causes of, iii. 760, Water^cells of the camel’s stomach, s. 507. 536. Water-rat (Arvicola amphibius), iv. 3S9. hibernation of the, ii. 764. See Hibernatiox. Water-scorpion (Nepa cinerea), ii. 8f8. jrater-sna/ces (Hydrophyli^, mode of progression of the, iii. 434. Watc7'-spide)\ instinct guiding the formation of her singular habitation, iii. 9. Watery vapour exhaled from the lungs, ii 140. il'a^ of the ear. See Cerumen; He.aring, Orgxn of. Weasel tribe ( Mustelidcc), dentition of the, iv. 913. Weevil^ its ravages in granaries, ii. 862. Weight of the human body at different ages, i. 74. Whales^ i. 5G2, et scq. spouting apparatus, i. 580. brain of, iii. 696. absolute weight of the brain of the, iii. G6t. chemical characters of whale oil, ii. 233. vocal organs and voice of whales, iv. 1494, 1495. See Cetacea. Whao'tun's duct, iv 424. Wheat, cause of the ear-cockle or purples in, ii. 1 13. Wheel animalcules, generative organs of, ii. 410. dormant vitality of, iii. 157. Whhlivigs, societies of, iii. 16. Whistle-bone^ or huckle-bone. See Coccyx. White of the eye (tunica albuginea), ii. 17-1. White matter of the nerves, iii. 586. C46. 654. See Ker- vous 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. 78. or chronic strumous arthritis of the knee, iii. 60. anatomical characters of the disease, iii. 62. first stage, iii. CO. 62. second stage, iii. 61, 62. prognosis, iii. 61 . symptoms, iii. 60, 61. of the wrist, iv. 1524. false, ii. 528. H hi/tl's views of the physiology of the nervous system, iii. 721 B. Willis, circle of, iii. 673. 705. lateral, or posterior communicating, branch of internal carotid artery of Willis, i, 402. IVilsori’s muscles, iii. 932. Wings ol insects, ii. 419. 539. 924. articulations of the wings, ii. 926. file of the wings, ii. 928. neuration, or distribution of the tracheas in the wings, ii. 926. origin and development of the wings, ii. 925. table showing the areas of the wings and the weight of the body in various species of insects, iii. 424. of birds, iii. 421. Winking, action of the eyelids in, iii. 79. Winslow, foramen of, i. .502. Winter egg, or hibernating ovum, 8. [117]. [119]. [127], [128]. See Ovum. Jf’ire-worm, ii. 861. ravages of, in meadows and corn-fields, ii. 861. Wolf-Jish, dental apparatus of the, iii. 978. W<'lfitin bodies, iv. 982 ; s. 594. Womb. See Uterus. Wombat, characters of the, iii. 267, et scq. Wombat, digestive organs of the, s. 304. pelvis of the, s. 160. Women, depravity of, among the ancients, ii. 686. Wood-mouse, hibernation of the, ii. 764. See Hiberna- tion. Woodpeckers, mode of climbing and apparatus for prehen- sion, iii. 451. Wormiana ossa. See Cranium. Worms (.Annelida), digestive organs of the. s. 297. eartli-worms, organs and mode of progression of the, iii. 441. ova of, s. [117]. luminousness of the earth-worm, iii. 193. parasitic. See Entozoa. found in the liver, iii. 196. See Liver — Entozoa. Wounds of arteries, cannon-shot anti gun-shot, i. 2j7. of the cornea, ii. 177. ol' the diaphragm, ii. 6. ll'rasse, teeth of the, iii. 973. Supp. Wrisberg, nerves of, i. 360. cutaneous nerve of, iv. 756. Wrist-Joint, iv. 1505. normal anatomy, iv. 1505. bones which constitute the wrist-joint, iv. 1505. radius, iv. 150.5. scaphoid, semilunar, and cuneiform bones of the carpus, iv. 1.506. fr?T5^-joint, triangular cartilage of, i. 249. mobility of the. i. 256. ligaments, iv. 1.506. anterior radio-carpal, iv. I5C6. posterior radio-carpal, iv. 1506. external lateral ligament of the w'rist-joint, iv. 1507. internal lateral ligament, iv. 1507. synovial membrane, iv. 1507. rnechanical 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. 15!3. of the bones of the forearm backwards, with displacement forwards of thecarpus, 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 tlie bones of the carpus, iv. 1516. fractures of the lower extreniity 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 iow’er extremity of the ulna, iv. 1521. disjunction of the lower epiphysis of the radiu-S, iv. 1.521. cases, iv, 1521. disease, iv. 1523. acute artliritis of the radio-carpal and of the inter-carpal articulations, iv. 1523. chronic strumous arthritis of the wrist, or white swelling, iv. 1524. anatomical characters of the disease, iv. 1525. chronic rheumatic artliritis of the wrist, iv. 1526. anatomical characters, iv. 1527. synovial tumours of the region of the wrist, iv. 1.528. morbid condition of the synovial burs® of the flexor tendons, iv. 1528. painful crepitation of tend- ns around the wrist, iv. 1529. surgical anatomy of the wiist. See Hand. wrist-joint couti'asted wiih ankle-joint, i. I5i. X. Xnntkic oxide (xanthin) calculus, iv. 80. Xanthoproteic 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. 1021. Y. Y-skaped cartilage of pelvis, s. 117. 120. Yapock, or fresh-water opossum, iii. 261. Yawning, probable causes of, iii. 722 K. sympathy in, iv. 852. influence of. on paralytic limbs, iii. 40. IVrt.s^-plant, mode of leproduction of the, s. 224. Yelk, yolk, or vitellu«, of egg, s. 3. 68. See Ovum. }«)lk-mass, s. [86]. Youth, periods of, at wliich the animal heat differs from that of the adult age, ii. CC3. 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 srq. Zephroniadee, a family of Myriapoda, iii. .516, ct scq. characters of the family, iii, 546. 3 M 890 GENERAL INDEX. Toanthidcc, a family of Polypifera, iv. 19. characters of the family, iv. 19, 20. genera of, iv. 20. Zoanihus (Cuv.), Actinia sociata (Ellis), a genus of Poly- pifera, iv. 20. Zc^/> ami meaning of the terms, as applied by the Greeks, iii. 143, no/e. Zona pelUiclda, or external tunic, of ovum of Mammalia, s. [HZ]. contents of ovum, or parts within the zona, s. [HO]. Zonula membrauacea laminae spiralis, s. zona Valsalvae, ii. .'=>34. Zoophuta, organs of circulation in, i. G53. litt of Zoophytes possessing the property of luminous- ness, i:i. 198. 7jOOspcr)7is^ or Spermatozoa, ii. 112. See Entozoa j Sper- viati>xua. Zoophaga^ tribe of, characters of, i. 563. Zoospores, 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. Zygncinacccc, mode of reproduction of the, s. 219. Zygoma, i. 749. Zygomatic 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. Zygo7naticus major muscle, ii. 221. relations and action, ii. 224, minor, ii. 221. relations and actions, ii. 224, Zi/gowG/o-maxillary, or external, surface of palate bones, ii. 210. THE END. J.ONPON rUlNTED P>Y SPoniSWOOnR AND CO. NEW-SrilELT SQUARE. C03V3PLETS0IS3 ©F DR. ©©PL^WO’S IViEDlCAL DleT3©^3ARY Just published, Pauts XTX. and XX. (a double Part, completion, with classified Contexts and a copious Index) price 9s. sewed; and YoLUiiE III. (in two Parts) 8ro. price £2. Ils. cloth, A DICTIONARY OF PEACTICAL MEDICINE. 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I.ight — Darkness — Heat — Cold — Electricity — Magnetism— Food— Exercise — Climate- Modes of ascertaining the Effects of Medicine — Active Forces of Medicines — Changes effected in Medicine by the Organism — Physiological Effects of IMedicines — Therapeutical Effects of Medicines — Parts to which Medicines are Applied — Classification of Medicines — Remedies acting on tlie Organs of Respiration — Remedies acting on the Nervous System— Remedies acting on the Digestive Organs — Remedies acting on the Perspiratory System — Remedies acting on the Sexual Organs — Water — Distilled Waters — Sea Water —Mineral Waters— Plumbago— Carbonic Acid — P.orax — Phosphorus — Sulphur — Sulphuric Acid — Chlorine — Iodine — llromine — Nitrogen, and its Compounds witli Oxygen and Hydrogen — Ammonia — Potash - Soda— Soap— Rosin— Li me — M agnesia — Mmnen — Chromic Acid — .Manganese — Arsenic — Antimony— Bismuth— Zinc — Tm — Lead — Iron and its Compounds— Copper— .Mercury— Silver -Gold- Platinum — Irish .Moss— Corsican Moss— Wall Lichen — Yeast or Barm — Mushroom — Champignon — Maidenhair— Rice— Oats— Darnel — Wheat— Bread — Rye— Ergot of Rye — Sugar — Sugar-Cane— Sago — Areca-Nut— Saffron -Mellehore— Aloes -Indian Aloes _ Stiuill — Garlic — Saffron Crocus — Arrow-Root — Ginger— Turmeric— Vanilla — Sarsaparilla— Turpen- tine— Oil of Torpe'ntine — Tar— Savin— Willow — Gall, or Dyer’s Oak— Cork— Hemp — Hop — Black Pepper — White Pepper— Cuheh Pepper— Croton Oil— Castor Oil— Snake-Riiot — Cinnamon — l-aurel — Nutmeg— Rhuharh — Peppermint — Horehonnd — Foxglove — Deadly Nightsli.ade—Tliornapple— Tobacco (Virginia) Potato — Tea — Coffee — Cocoa — Chocolate — Scam- mony— Jalap— Gentian — Nux Vomica, or Strychnia — Olive — Manna — Storax — Beiuoic Acid — Gntta Perclia— Indian Tobacco — Elecampane— Dandelion — Chicory — Valerian— Ipecacuanha— Dover’s Powder — Bark (Cinchona)— Elder — Caraway — Coriander — Assafoetida — Ammonia — Galhanum — Hemlock — ■ Colocy nth— Wild Cucumber — Clove— Pomegranate — Almond— Prussic Acid— AlmoncI Milk— Wild Cherry — Rod Rose — Bean — Balsam — Vetch — Acacia — Logwood— Senna — Copaiva— Poison Oak — Myrrh — Rue— Angustura Bark— Oxalic Acid — Tartaric Acid —Gin —Brandy — Spirits of Wine — Ethyle — Ether — Metliylated Spirits — Acetic Acid — Chloroform — Gamboge— Lemon-Tree and Fruit— Orange-Tree and Fruit — Mallow — Flax — Violet — Horse Raddish — Poppy — Opium — Laurlanum — Morphia — Cocculus Indiciis — Black Hellebore — Monkshood— Geranium — Creasote— Sponge— Oyster— Leeches— Spanish Fly — Cochineal — Honey — Isinglass — Cod Liver Oil — Mnsk Animal— Stag— Ox— Beaver — Badger — Tabular View of the History and Literature of Materia Medica. London: LONGMAjS!, BEOWAT, .'inci CO., Paternoster Eow. I Todd V.5 1859