ru LIBRARY OF = CONGRESS, | | | UNITED STATES OF AMERICA. | THE REPRODUCTIVE PROCESS: ITS HISTOLOGY, PHYSIOLOGY, AND PATHOLOGY. DEMONSTRATING THE UNITY OF THE ANATOMICAL TYPE OF THE PLACENTA IN ALL THE MAMMALIA, AND THE PHYSIOLOGICAL UNITY OF THE NUTRITION OF THE FETUS IN ALL THE VERTEBRATES. BY f Pror. GIOVANNI BATTISTA ERCOLANI, PERMANENT SECRETARY OF THE ACADEMY OF SCIENCES OF BOLOGNA; CORRESPONDING MEMBER OF THE ACADEMY OF MEDICINE OF PARIS AND BRUSSELS, OF THE IMPERIAL ACADEMY OF BERLIN, OF THE AMERICAN MEDICAL ASSOCIATION, BOSTON GYNECOLOGICAL SOCIETY, ETC. IN TWO VOLUMES: ONE A QUARTO ATLAS OF ILLUSTRATIONS, ENGRAVED BY BETTINI, AND REPRODUCED BY THE HELIOTYPE PROCESS. TRANSLATED BY HENRY O. MARCY, A.M., M.D. PRESIDENT OF THE BOSTON GYNECOLOGICAL SOCIETY; LATE PRESIDENT OF THE AMERICAN ACADEMY OF MEDICINE; MEMBER OF THE AMERICAN MEDICAL ASSOCIATION, BRITISH MEDICAL ASSOCIATION, MASSACHUSETTS MEDICAL SOCIETY ; CORRESPONDING MEMBER OF THE MEDICO-CHIRURGICAL SOCIETY OF BOLOGNA, ITALY; LATE SURGEON U. S. A., ETC., ETC. Cree v »# My HOUGHTON, MIFFLIN AND COMPANY, New York: 11 East Seventeenth Street. Che Viiversive Press, Cambridge. 1884. 7 SK o> Copyright, 1880 and 1884, By HENRY O. MARCY, M. D. The Riverside Press, Cambridge: Electrotyped and Printed by H. 0. Houghton & Co. PREFACE TO THE SECOND EDITION. Tue first edition of Professor Ercolani’s works, translated and published in 1880, received the high- est commendation not only from the medical profes- sion but also from scientists, in both England and America, Fundamental facts necessary to the proper under- standing of many of the conditions of the pregnant state were for the first time presented, explained, and emphasized, and thereby much new light was thrown upon this most mysterious of all of Nature's processes. The present edition has been enlarged more than one fourth, including the long-continued and painstak- ing researches of the author upon the pathological changes incident to pregnancy. A careful study of these chapters can result only in profit and practical advantage to every practitioner of medicine. I have myself repeated many of the observations of the learned author, and have thus in assurance the correctness of his statements and conclusions. As if in the fore-knowledge of his untimely end, Professor Ercolani, only just before his death, reviewed his en- tire work wm extenso, with a long résumé of careful conclusions which is also included in the present vol- ume. HENRY O. MARCY. 116 BoyLsTon ST., Boston, March, 1884. TRANSLATOR’S PREFACE. THE translation and editing of the several mono- graphs of Prof. G. B. Ercolani has been undertaken from the conviction that their publication in English would be of service to science. The opinions, at a greater or less length, of this dis- tinguished scientist are quoted in nearly all the mod- ern text-books treating upon this subject, and yet so indefinitely in many instances, and even erroneously, that it is evident authors have not familiarized them- selves with the elaborate and painstaking studies of Professor Ercolani. So important are these demonstrations and the truths derived therefrom, so radically different are his teachings from the time-honored views still held and generally taught, that I have felt the medical profession and students of natural history would gladly avail themselves of the opportunity of care- fully examining these original investigations. Espe- cially have they seemed to me valuable because of the attention which the study of the human placenta has received of late by many careful observers, and still more so since their conclusions are by no means unanimous. Anatomists and physiologists have long experienced the great necessity of a clearer knowl- vi TRANSLATOR’S PREFACE. edge upon many of the reproductive processes. More recently the gynecologist seeks in the changes of the utero-gestation period a solution to many of the path- ological questions demanding his attention. Since the classic work of Wiliam Hunter a century has passed with only a very few additions to what was actually known in reference to the nutrition of the embryo. Professor Ercolani’s monographs appeared origi- nally in the Transactions of the Academy of Science of Bologna. The memoir was translated into French by Prof. R. Bruch and Dr. R. Andreini, for whom the Appendix here given was written, and has received an award from the Academy of Sciences at Paris. I am under a personal obligation to these gentlemen, since it was the study of their translation which prompted its reproduction for the English reader. To my friends, M. Smead and S. 8. Jacobs, who have so very thoroughly performed the work of translators, I would express my gratitude, for with- out their faithful aid this translation would never have been presented to the public. Whatever faults of diction or liberty taken with the translation for clearness of expression is assumed by myself. The work on my own part has been a labor of love. Stimulated by the teachings of the learned Professor Martin, of Berlin, during the last decade, I have im- proved every opportunity for original investigations in this direction, and have verified a number of the observations made by Ercolani. Original study never lacks interest or loses value. The author declares that “Science is pure and simple truth,” and states that his aim has been to establish the fact that the maternal portion of the placenta of TRANSLATOR’S PREFACE. Vil mammals and the human species is always a glandu- lar organ of new formation, and is developed for the secretion of a fluid, which serves for the nutrition of the foetus. The placenta consists in all animals of two distinct fundamental parts, the foetal portion, vascular and absorbent, the maternal, glandular and secretory. In no case do the vessels of the mother anastomose with the vessels of the foetus. He elucidates the nature and metamorphosis of the utricular glands of the uterus, and resolves affirmatively the question as to the presence of a uterine mucous membrane in woman. In the same manner as, in the first period of extra- uterine life, the young is nourished by the mother’s milk, absorbed by the villi of the intestine, so, during intra-uterine life, the foetus finds its nutriment in the maternal fluid secreted by the glandular organ. In the eggs of birds and reptiles there is elaborated be- forehand, by the mother, and stored up, all the nutri- tive material necessary for the development of em- bryonic life. | New teachings are rarely announced without find- ing opponents, and this is true of the work presented. Professor Ercolani writes, “ This opposition has been advantageous to me ; I was so sure of the facts that I should have perhaps remained inactive and not have taken the trouble to observe and follow the dif- ferent periods of development of the glandular organ in animals and in woman. I brought forward these new deductions from my recent observations in the public conference where I replied to the objections of Professors Albini, Palladine, and Ohel.” In this dis- cussion he stated in the frankest and most conscien- Vill TRANSLATOR’S PREFACE. tious manner certain errors of interpretation in the first facts announced. By these researches is opened an almost unex- plored field in the pathology of gestation, and this, too, is essentially the medical and more practical side of the subject. In the abnormal development of the placenta and in the modifications of the nutrition of the foetus will be found causes hitherto unknown of embryonic disease and arrest of intra-uterine life. Therefore it will be seen that the work of the Bo- logna professor has an intimate connection and bear- ing upon anatomy and physiology, chemistry and pathology, embryology and anthropology, biology and obstetrics. It destroys ancient and classic er- rors; it demonstrates an important new anatomical fact; it teaches a new physiological function, and clearly shows a simple and fundamental plan of em- bryonic life. The evident impartiality of the author, as shown in his numerous observations, the multiplicity of facts produced, the modest and conscientious expression of opinion, and the beautiful illustrations of his studies in the accompanying volume of plates appeal to the unprejudiced reader, and carry conviction that the deductions presented are the results of thoughtful labor, and not preconceived theories which he has endeavored to demonstrate. The establishment of such facts will cause the name of Ercolani to be classed with the great benefactors of science and be handed down to coming generations, honored alike with Eustachius, Malpighi, Morgagni, and other dis- tinguished anatomists of the early Italian school. HENRY O. MARCY. CAMBRIDGE, January, 1880. CONTENTS. CHAPTER I. PAGE. SEEM C TRONS hottie iat! el I e e A belt vas RO 0 Fy CHAPTER II. THE UTRICULAR GLANDS OF THE UTERUS IN THE MAMMALIA IN THE GRAVID AND NON-GRAVID ANIMAL. Their development and function ... +... + +... + 6-26 CHAPTER III. ON THE GLANDULAR ORGAN, OR THE MATERNAL PLACENTA, IN ANIMALS WITH A VILLOUS OR DIFFUSED PLACENTA. Opinions of the ancients. —- Histological changes of the uterine mu- cous membrane. — Illustrations drawn from the mare, as seen in Plate III., Figs. 1, 2.— Demonstrations, from the studies of com- parative anatomy, that there exists a true uterine mucous mem- brane in all animals, including the human species. — The trans- formation which the uterine mucous membrane undergoes during pregnancy to give rise to the neo-formation of a transitory glandu- lar organ constituting the maternal part of the placenta. — Pro- liferation of sub-mucous connective tissue. — Glandular follicles of new formation and their secretory function . . . +. +. . 27-46 CHAPTER IV. THE GLANDULAR ORGAN, OR MATERNAL PLACENTA, IN ANI- MALS WITH A MULTIPLE PLACENTA, AS IN THE RUMINANTS, OR THE UTERINE COTYLEDONS IN THOSE ANIMALS. Opinions held by the earlier writers. — The fluid furnished by the cotyledons : its character, chemical composition, etc. — Fabricius and his followers taught the direct communication of the maternal vessels with those of the fetus in the cotyledons. — Harvey main- tained that the fluid secreted by the cotyledons was absorbed by CONTENTS. the villi of the foetal placenta. — Formation and development of the cotyledons. — The structure and function of the utricular glands. — Histological characters as illustrated by Plates V. and VI. . e DI e e e e e e e e e e . e . . . e e 4 7-64 CHAPTER V. THE GLANDULAR ORGAN, OR MATERNAL PORTION OF THE PLA- Is CENTA, IN ANIMALS WITH A SINGLE PLACENTA. the placenta entirely feetal, or is it distinguishable into two parts, one maternal and the other fetal ?— Harvey, Fabricius, Wharton, Needham, Malpighi, of the early writers. — Views of Von Baer, Sharpey, Weber, Bischoff, Eschricht, Panizza, and others.— The doctrine erroneous that the exchange of materials for the nutri- tion of the fcetus is carried on by the process of endosmose and exosmose through the walls of the maternal and fcetal vessels. — Two different periods of fetal nutrition. — A glandular organ of new formation demonstrated by the aid of studies upon animals having a diffused or villous placenta. — The placenta of animals, although single, as distinct from that of the human species. — Plate VII. shows sections from the placenta of the rabbit, teaching its histological development. — Among the carnivora the dog has been selected, and Plates VIII. and IX. teach that the placenta is formed in the same manner as in the rabbit. . . . . . 65-101 CHAPTER VI. THE HUMAN PLACENTA. The changes which the surface of the uterus undergoes at the pla- cental site. — Opinions held as to the mode of formation and structure of the uterine decidua. — The decidua serotina so pecul- iar as to prevent its being confounded with the uterine and re- flected decidua. — The exterior membrane surrounding the villi of the chorion is furnished by the decidua serotina. — Hypertro- phy and hyperplasia of the anatomical elements constituting the connective tissue, and the transformation which gives rise to the development of special neutral cells, from which is formed the new glandular organ, or maternal portion of the placenta. — Plate X. represents a vertical section of the uterine surface of the placenta. — Distinctions between the human placenta and that of animals. — The utero-placental vessels and venous sinuses. — Lacunar circulation. — Ectasic condition of the maternal vessels. —TIn all the mammalia, including the human species, the mater- nal portion of the placenta is always a glandular organ of new formation Lis ala Ve Ole eR i re eee CONTENTS. XxX1 CHAPTER VII. I. CONCLUSIONS RELATIVE TO THE UTRICULAR GLANDS AND THE MUCOUS MEMBRANE OF THE UTERUS. Erroneous views of anatomists and physiologists who have held that in certain animals there were two species of uterine glands. — The uterine decidua of woman a product of the utricular glands. — The glandular secretion for the nutrition of the embryo until the development of the new glandular organ which constitutes the maternal portion of the placenta . . . . . +... . . 130-136 If. CONCLUSIONS UPON THE GLANDULAR ORGAN OF NEO-FORMATION, OR MATERNAL PORTION OF THE PLACENTA, IN THE MAMMALIA AND IN THE HUMAN SPECIES. The placenta composed of two parts entirely distinct both in struct- ure and in function: the fetal portion, vascular and absorbent; the maternal portion, glandular and secretory. —In no case do the vessels of the mother come in contact with those of the foetus. — The fcetus always nourished by the fluid secreted by the glandular organ and absorbed by the villi of the chorion. . . . . . 137-145 APPENDIX. I. THE FORMATION OF THE MATERNAL OR GLANDULAR PORTION OF THE PLACENTA IN THE HUMAN SPECIES AND IN CERTAIN ANIMALS . e ° ° ° ° e e DI ° CD ° e . . e CI . 147-150 II. FORMATION OF THE MATERNAL PLACENTA IN THE COW, SHEEP, MOLE, AND HIND . e e . e e . . D ° ° . O . 150-156 IIK FORMATION OF THE SINGLE PLACENTA IN THE CAT, THE HARE, AND DHE GUINEA-PIG e. ii 'ollebta le debiti «ss 107-168 IV. FORMATION OF THE PLACENTA IN WOMAN AND IN THE MON- KEY e CD) . e . . ° e ° e e e e e e e . è . 169-174 xii CONTENTS. MONOGRAPH. THE UNITY OF THE ANATOMICAL TYPE OF THE PLACENTA IN THE MAMMALIA AND IN THE HUMAN SPECIES, AND THE PHYS- IOLOGICAL UNITY OF THE NUTRITION OF THE FETUS IN ALL THE VERTEBRATES. i. Comparative anatomy reveals the structure of the human placenta and demonstrates the unity of the anatomical type in all animals. — Newly observed facts explain the origin of the elements of the decidua and the maternal portion of the placenta, hitherto lack- ing positive demonstration.— The complete destruction of the uterine mucous membrane, and the subjacent parts, indispensable in all cases to the establishment and development of the neo-for- mative changes, from which will result the maternal portion of the placenta. — Plate I. represents the gravid uterus of the rabbit about fifteen days after conception, at the beginning of the forma- tion of the placenta. — Plates II., III., and IV. further illustrate the destructive and neo-formative changes in different animals. — Deductions and conclusions . . . . . . .... « « 12665 II. PHYSIOLOGICAL UNITY CONTROLLING THE NUTRITION OF THE FETUS IN ALL VERTEBRATES. Maternal aliment, and the means by which it may be appropriated by the embryo. — Represented by the yolk of the egg in the ovip- arous animals and by the placenta in mammals. — Nature accom- plishes her purpose for the nutrition of the embryo by mate- rials furnished by the mother. — The Marsupialia. — Plate V. illustrates in diagram the unity of type in the various forms of placenta. — Relation between the fetal and maternal parts by simple proximity, contact, or by intimate cohesion. — Relations between the fetal and the maternal portion of the placenta in woman identical with those observed in single placente in the other mammifera. — Summing up of principal facts. — One law, a physiological modality governs the nutrition of the fetus in all the vertebrates . << . . 6 « 6 e's eee SUMMARY AND CLASSIFICATION. Acotyledonous placente: single, villous, and diffused. — Compli- eated villous. — Localized villous. — Cotyledonous placenta of in- complete and with complete vascularization.— With ectasia in the vessels of the maternal portion of the placenta. — Table of classification of the vertebrates. — Conclusions . . . . +. 272-296 CONTENTS. Xi DISEASES OF THE PLACENTA. n CHAPTER I. PATHOLOGICAL CHANGES OF THE UTERUS. Observations of different authors upon these morbid processes. — The confused and inaccurate opinions hitherto held concerning the anatomical structure and development of the placenta the cause for much of the uncertainty belonging to its pathology. — The principal difficulties that have prevented the author from ad- Vancino in his new researches. . è. + è + « « « « + 297-300 CHAPTER II. PATHOLOGY OF THE CHORIAL AND OF THE PLACENTAL VILLI. The villi of the chorion during the early months of pregnancy com- posed of two parts, internal or parenchymal portion. — External portion composed of an epithelial envelope. — Increase of these chorial villi in number and size. — The cells of the uterine de- cidua do not proliferate as do the cells of the serotina. — The chorial villi, if any remain, when the placenta is fully developed, still covered with an epithelial layer. — Placental villi lose this envelope. — The mucous tissue of the villi of two parts, one, in- ternal, homogeneous, in which is inclosed the other, formed of large nucleated cells. — Pathological changes occurring in the foetal portion of the placenta established in these elements of the RR wh, ilo ann ew) 0 CHAPTER III. HYPERTROPHY OF THE CHORIAL VILLI OR MYXOMA OF VIRCHOW. Parenchyma of the chorial villi formed of mucous tissue. — Opin- ions of authors as to the seat of the pathological change in hyda- tid placenta. — Demonstrations showing that the hypertrophy of the chorial villi and the microscopical pyriform productions are of epithelial origin. — The parenchyma of the villi do not aid in their formation, either in the external membrane of the hydatid cysts or in the liquid they contain, as believed by Miiller and Virchow 305-309 X1V CONTENTS. CHAPTER IV. HYDATID PLACENTA. Contradictions of various authors as to the genesis and development of the hydatid placenta. — The vesicles constituting hydatid pla- centa of twofold origin. — Myxoma of the hypertrophied chorial villi originates in a proliferation of the epithelium covering them ; myxoma of the placental villi begins upon the external envelope which belongs to and is a part of the glandular maternal organ. — Vesicles and pedicles a new pathological change of the epithelium. — Changes in the cells of the vesicles explaining the increase in volume, etc. — The cells of the pedicles seldom undergo any trans- formation. — Description of an hydatid placenta, showing the pres- ence of the parenchyma of the villi in the interior of the ves- icles, as absolutely impossible . . . . +. +. +. +... . 310-319 CHAPTER V. MYXOMA OF THE SEROTINA. Observations of earlier writers who maintained that hydatid pla- centa was a disease of the decidua. — Sirelius first to point out the relation of the feetal villi with the cells of the serotina, the ex- ternal envelope furnished later to these villi by the serotinal cells, and the idea of a maternal organ analogous to the glandular organ for the nutrition of the fetus. — Chorial villi never found amid the cells of the serotina, the placental villi always in the decidua serotina. — Description of a section of a placenta show- ing the denomination myxoma, given by Virchow to this disease of the chorial villi, incorrect . . . . .. . . =. . . 320-325 CHAPTER VI. FATTY DEGENERATION OF THE PLACENTA. All anatomists hitherto have regarded the scirrhous nodules and fatty masses due to bloody effusion. — Robin demonstrated the uncertainty of these views. — The preponderance and increase in volume of the cells in the mucous tissue of the placental villi the fundamental and peculiar characteristic of fatty degeneration. — Review of a case of sclerosis. — Reasons for giving the denomi- nation deformed cellular hyperplasia instead of sclerosis of the placenta ‘LL dui ace in È lA ee ERE E CONTENTS. XV CHAPTER VII. FIBROMA OF THE VILLI AND OF THE SEROTINA. Observations proving that connective tissue transformation may at- tack the serotina as well as the villi.— Fibrous change of the villi; different characteristics according to the period of the evo- lutive process of the mucous tissue of the parenchyma of the villi into fibrous tissue. — Change of the normal cells into fusiform cells, then into corpuscles of connective tissue. — Change of the liquid matter. — Description of a placenta aborted about the fourth month, showing the most interesting phenomena of fibrous change. — For- mation of lacune effected in a manner analogous to the process of vascularization in the erectile tissues. — Origin of the lacune . 339-352 CHAPTER VIII. MELANOSIS OF THE PLACENTA. Description of a placenta in which the lesion showed deposits of pigment in the villi, though there had not been a drop of liquid blood, for they had not yet reached vascularization. The materi- als of the maternal blood, destined to nourish the foetus, go out from the utero-placental vessels, are absorbed by the villi after being elaborated by the serotional cells, in passing through which they leave traces of hematoidin. This pathological lesion gives much light relative to foetal nutrition in the early period of intra- MERIC ROSVEIOPMENt i.e we, oi oe a) gd CHAPTER IX. SYPHILITIC LESIONS OF THE PLACENTA. The utero-placental vessels which penetrate into the serotina in- stead of dilating normally for forming lacune, increase and de- velop in the midst of cells which are the same in the decidua, serotina, and vera in the early period of gestation. — Syphilitic and non-syphilitic angiomata of the placenta and of the de- SIA se Tart ches os) ar Len cave env ares ec all tlc A uM OGM CHAPTER X. THROMBI, APOPLEXY, AND HA MORRHAGE. The localized collections of coagulated blood in the placenta a mor- bid form of disease often found in abortions of advanced preg- nancy. — Some believe true hemorrhage impossible, others that XV1 CONTENTS. apoplexy is always the result of a lesion of the villi.— Fatty de- generation the most common and potent cause of internal hemor- rhage of the placenta. — Hemorrhage usually the result of lacer- ation of the maternal vessels. — Review of vascularization of the placenta. — Causes of hemorrhage in the early months of preg- nancy. — Fatty degeneration extending into the cells of the de- cidua serotina at all periods of pregnancy an occasion of severe and fatal hzemorrhage . ..)-4e!\.)j2 is) Te eo ie pie =) ee CHAPTER XI. TRANSFORMATION OF BLOOD CLOTS AND NEOPLASIA OF THE PLA- CENTA. Changes in the blood coagulated from thrombi and remaining in the placenta. — The organization of blood clots. — The villi comprised in old clots present the obliteration of the vessels and fatty degen- eration accompanied with atrophied deformation when the clot is composed only of fibre [5 ie ee) Ss en eee CHAPTER XII. PLACENTAL CYSTS. Report of clinical cases of cystic degeneration of the placenta. — The denomination cyst incorrect. — The so-called placental cysts usually of traumatic origin, really a circumscribed hemorrhagic form of maternal'blood if. 9 0s (3s) ee CHAPTER XIII. CALCAREOUS CONCRETIONS OF THE PLACENTA. Calcareous concretions found generally upon the uterine surface, either stellated or needle-shaped. — Composed of carbonates and phosphates of lime and magnesia... . . . . .. +. + 3889-391 CHAPTER XIV. ABNORMAL DEVELOPMENT OF THE PLACENTA. Description of a placenta aborted at the fifth month, confirming many facts upon the formative process of the organ, and that in its evolution there may be anomalies of development causing abor- tion. — Are placental changes the consequence or the cause of the death of the embryo ?— When the dead fetus remains in the CONTENTS. xVil uterus and the placenta continues to develop isolated, the prob- lem cannot be solved. — Diseases of the maternal placenta of greater significance than those of the fetal . . . . . . 392-396 NEW RESEARCHES UPON THE NORMAL ANATOMY AND PATHOLOGY OF THE PLACENTA OF MAMMALS AND OF WOMAN. Review of the opinions held by early writers, and especially of the celebrated anatomist and embryologist, Professor Kolliker, upon the placental development in the deciduate and non-deciduate mam- mifere and animals. The author’s reasons for differing therefrom, containing his most recent observations. . . +. + . . + 397-417 EULOGY DELIVERED AT THE FUNERAL OF PROFESSOR ERCO- LANI, BY PROFESSOR GIROLAMO COCCONI. . .. » . 418-426 UTRICULAR GLANDS OF THE UTERUS. CHAPTER I. INTRODUCTION. THE observations which I have the honor to present upon the formation and structure of the placenta in the human species and among the mammalia have led me to such different conclusions from those which are generally admitted at the present day by anato- mists and physiologists that I feel it necessary, at the outset, to appeal to the benevolent attention of my readers. I shall further need indulgence, because I shall be obliged to describe very minutely a great number of researches which concur, in their whole, to explain the general idea of my work. For this reason, then, and for the sake of suitable method also, it seems advisable to begin with illustrating this gen- eral idea by afew diagrams, and afterwards to discuss the researches and observations of which that idea is the result, and which I will sum up as follows: There is produced in the pregnant uterus of mammals, in- cluding the human species, a glandular organ of new formation. This organ constitutes one of the two fundamental portions of the placenta, that is to say, the maternal portion, with which the foetus is brought into intimate relation by the villi of the chorion, 1 2 INTRODUCTION. which composes the other portion of it, or the foetal part. | The villi of this latter part of the placenta pene- trate always and obviously into the glandular organ or maternal part, in order to absorb the fluid which is there secreted, and thus to furnish the foetus with the materials necessary for its nutrition. The typical form of the new glandular secreting organ does not depart from the common form of a simple glandular follicle of the animal organism. Likewise the typical form of the foetal placenta, or absorbing portion, is that of a vascular loop, more or less elongated, or of a villus. This is observed, with a few rare exceptions, in the three fundamental species of placenta admitted by anatomists under the names of disseminated, diffused, or villous placenta, multiple placenta, and single placenta. In the diagrams, I have represented vertical sec- tions of the uterus and of the placenta of animals and of the human species, in order that the relations always existing between the two portions of the pla- centa may be more clearly demonstrated. Figure 1, Plate I.,is taken from the mare, as an example of the villous placenta. At the top is the chorion (a), from which issue the vascular pencils or tufts and the villi (4, ¢, ¢) of the foetal portion, which penetrate into as many simple glandular follicles (d) of the maternal portion, developed, during preg- nancy, over the whole surface of the uterus, the walls of which are indicated by e e. This is the sim- plest possible type of the double structure of the placenta. In Figure 2 of Plate I. I have in like manner indi- INTRODUCTION. 3 cated the same portions of the multiple placenta, taking as the type that of the cow, which offers the simplest form of this kind of placenta common to ru- minants. Although the glandular organ is here mod- ified, it does not lose its elementary form of simple follicle. The only change is in the degree of prox- imity and the position of the follicles. In the disseminated or diffused placenta we have seen the follicles placed vertically over the whole in- ternal surface of the uterus; here, on the contrary, they are parallel to the same surface, and superim- posed over each other, at the points where the vari- ous placentz are developed (d, d). The relations of the villi with the follicles are the same as in the pre- ceding case. As for the single placenta, we must not confound, in one type, that of certain animals and that of the human species. In the dog and cat (Plate I, Fig. 3) the typical form of the glandular follicle is not lost ; but, instead of being repeated in its simple form, as we have seen it in the cow, it is extraordinarily elongated into tubular glands, as it were, which are packed closely, by their walls, against the villi of the foetal placenta. The opening of the follicles on the surface of the placenta occurs at the place where the villi of the chorion penetrate (9). Their extremity, or closed end, is visible in the interior of the placenta towards its uterine face (9, g). Nevertheless, it is impossible to follow or isolate an entire follicle from its orifice to. its termination, on account of the complicated and sinuous structure of the enteriform loops, of their very intimate proximity to each other, and of their 4 RENTRODUCTIONE numerous connections with the substance of the pla- centa. It is in the human species that the structure of the glandular organ, or maternal placenta, differs in the most remarkable manner from the typical form of the simple glandular follicle. When discussing this organ, I shall point out the great differences which distin- guish it from that of the lower orders. For the pres- ent, I will only state that in the human maternal pla- centa the fundamental parts of the organ, that is to say the walls and the cells, — in a word, the secreting organ and the secretion itself, — are persistent; but all that relates to the form of a glandular follicle is completely lost. Figure 4 represents the human placenta. Contrary to what we observe in animals, that portion of the uterine surface which is in contact with the placenta is covered with a peculiar membrane of new forma- — tion, known to anatomists under the name of decidua serotina (7). This membrane, produced by the pro- liferation of the cells of the superficial or submucous connective tissue of the uterus, is the stroma whence originates the glandular organ which supports and envelops the villi of the foetal placenta in all their numerous subdivisions (d, d). The glandular organ accompanies the villosities as far as the chorion ; having reached this point, it loses its glandular structure and becomes altogether fibrous, in order to attach firmly to the chorion itself the ves- sels of which the umbilical cord is formed (9). By this prefatory general statement of the structure of the placenta in mammals and the human species, I have marked out the order which I shall follow in INTRODUCTION. 5 my work. As is well known, it has been taught and admitted by many authors that the uterine glands of animals, at least, if not those of woman, play a very important part in the formation of the placenta. It will therefore be fitting to treat first of these glands, then explain the structure of the placenta, — whether it is disseminated or villous, as in the soli- peds, or multiple, as in the ruminants, or single, as in the carnivora and noone ees conclude with the human placenta. I shall, moreover, preface each of these divisions by a few historical researches, for the special purpose of elucidating such of the new observations as appear to me of most importance. CHAPTER II. THE UTRICULAR GLANDS OF THE UTERUS. Matpicut was the first to make known the existence of the uterine glands. We learn from him’ that, hav- ing returned from Messina to Bologna, he resumed his well-beloved anatomical studies, and began at that time his researches upon the structure of the uterus. In describing these researches to Sponius, in a letter dated from Bologna in 16817? he wrote: — “Uterus interius membrana quadam ambitur, que minima et innumera habet orificia, glutinosum, mu- cosumque fundentia humorem, quo uterus ipse et vagina perpetud madent. Quare compresso utero prosilit hujusmodi mucosus ichor. Patent autem haec excretoriorum vasorum ora, si diù interior membrana aqua maceretur, et in ovibus precipue obvia sunt; quare probabile est, subvitellina exarata corpora his orificiis in uteri cavitatem hiare ; an vero his minime appendantur glandule, licet sensus non attingat, ratio tamen ex perpetuà operandi normà probabiliter eas suadet.” Although from this it is certain that the illustrious anatomist observed the fact in different species of animals, since he declares that we see in the sheep, better than in any other animal, the openings of the 1 Opera Posthuma. Venice, 1698, p. 46. 2 Opera omnia. London, 1686. UTRICULAR GLANDS OF THE UTERUS. 7 mucous membrane of the uterus, yet it will be well also to recall his words upon the opening of the uter- ine glands into the mucous membrane of the uterus in the cow: “In pregnantibus vero et precipue in vaccis, uteri stygmata obvia fiebant.” * These few words secure to Malpighi the merit of another quite important observation, namely, that the uterine glands increase in volume during preg- nancy. It is true that it was only from the orifices in the uterus that Malpighi inferred the existence of the glands, of which he had no demonstration by the senses. But we shall not venture to reproach him for this, if we reflect upon the limited means of inves- tigation at his disposal, and remember that the obser- vation was not repeated till one hundred and seventy years later. Besides, the learned anatomists who first repeated it, as the brothers Weber, at first consid- ered the uterine glands as villi of the decidua sero- tina.” It was not until some years later that they corrected their error, recognizing them for what they really are, and denominating them utricular glands of the uterus. Among the moderns, Baer? also, when he observed these same glands in the uterus of the sow and of the cow, took them for lymphatic vessels; and it was not until nine years later, after the observations and rec- tifications of the brothers Weber, that he recognized 1 Opera Posthuma, loc. cit. ? Disquisitio Anatomica Uteri et Ovariorum Puelle Septimo a Con- ceptione Die Defunct. Halle, 1830. ® Untersuchungen iiber die Gefissverbindung zwischen Mutter und Frucht in den Saugethiere. Leipzig, 1828. i 8 UTRICULAR GLANDS OF THE UTERUS. the glandular structure of the canaliculi which he had at first considered as vessels.’ Like Malpighi, Baer had observed the orifices in the mucous membrane of the uterus; but he had not been able to follow the canals to their extremity, for in the sow they are very long. It is evident that the brothers Weber and Baer, even while using the powerful means of observation which modern science has given us, judged by induction in their first re- searches, just as Malpighi had done. Now, if we compare the inductions and take into account the discouraging poverty of means at the latter’s disposal, we can only regard the great anatomist of Bologna with admiration. Following the development which the observation of Malpighi received in later times, we see that E. Weber, in the publication of the fourth edition of The Human Anatomy of Hildebrand,? claimed for himself the honor of having first recognized the ex- istence of the uterine glands, and of having named them utricular glands, giving, besides, a description of them in the uterus of the cow and the doe. I think we should not deny to Weber the merit of having established, beyond question, the existence of the uterine glands ; but if this is just with regard to Weber, equity also requires us to assign to Malpighi the merit which belongs to him. In 1854, Burkhardt? was acquainted with the labors of Malpighi, but he was ignorant of the first observa- tions of Weber and of Baer. So, notwithstanding the 1 Uber Entwickelungsgeschichte der Thiere. Konigsberg, 1837. 2 Brunswick, 1832. 8 Observationes Anatomice de Uteri Vaccini Fabrica. Basle, 1834. UTRICULAR GLANDS OF THE UTERUS. 9 teachings of the anatomist of Bologna, he did not recognize the tubular structure of the glands, and he described the uterine glands of the cow under the name of spiral vessels. He repeated his experiments upon the gravid and non-gravid uterus, and confirmed what had already been said by Malpighi, — that they increase in volume during pregnancy ; but, not being able, as he acknowledged, to form a precise opinion as to their office, he contented himself with suppos- ing that they were perhaps of some utility to the foetus. The later observations of Eschricht*® confirmed, in a great measure, those of Weber; he added a few upon the uterine glands of dolphins, and he noted some special features in those of cats. His observa- tions upon the latter animal are not exact, and their inaccuracy comes from the fact that Eschricht could not discover the orifice of the glands in the uterus. He does, however, notice the increase of volume which the glands undergo, in that animal, during gestation. So far, the observations upon the existence of the uterine utricular glands had no other importance than that of the knowledge of an anatomical fact which, though pomted out long ago, had not been demonstrated with the certainty desirable in such matters; and, indeed, apart from this demonstration, nothing had really been added to what Malpighi had said, either as to their existence or as to their in- crease in volume during pregnancy. This new anatomical idea did not become the point 1 De Organis que Respirationi et Nutritioni Fetus inserviunt. Co- penhagen, 1837. 10 UTRICULAR GLANDS OF THE UTERUS. of departure for a real scientific progress until Shar- pey! published his researches upon the uterine glands, especially those of the dog. He proved first, that in the dog there exist two species of utricular glands, the simple and the branching. He said that during preg- nancy the first do not increase in volume, like the second. He went still further: he taught that the branching uterine glands, which correspond to the point where the ovum is arrested after fecundation, un- dergo, near their mouths, a partial saccate dilatation, produced by the penetration of a villus of the chorion. We see that the idea that the fluid secreted by the utricular glands of the uterus served in some manner for the nutrition of the foetus was confirmed more and more. I say expressly that it was confirmed, for Burkhardt had beforehand suspected it, as it were, and Eschricht had taught more clearly and dis- tinctly that the uterine glands of the pachyderms, ruminants, and cetaceans elaborate a fluid destined for the nutrition of the foetus. Bischoff? repeated the observations of Sharpey upon the evolution of the embryo in the dog. He gave the name of crypts to the simple uterine glands of Sharpey, and demonstrated the fact of the penetra- tion of the villi of the chorion into the upper parts of the utricular glands. But he added that this fact is observed only during the first periods of gestation, and that, never having verified it later, he could not absolutely affirm it. It remained, however, fully es- tablished that, during the first period of intra-uterine 1 The observations of Sharpey are found in a note to the English trans- lation of Miller’s Physiology. 2 Entwickelungsgeschichte des Hundes. Brunswick, 1845. UTRICULAR GLANDS OF THE UTERUS. o life, the foetus is nourished by the liquid secreted by certain glands of the uterus. E. H. Weber! confirmed the researches of Shar- pey, describing the partial dilatations of the utricular glands and the attenuation of their walls, destined to favor the contact of the vascular net-work of these glands with that of the foetal vill, which fill their saccate dilatations. He limited his observations to the gravid uterus of the dog, and declared that he had not been able to demonstrate the same facts in that of woman. These studies, although lacking the clearness and precision to be desired in such matters, have remained an acquisition to science, and are met with in all re- cent works on physiology. But before deciding on their exact value, we must await further and more perfect observations. I ought not, however, to omit the mention of some opinions, published from time to time, which served to emphasize the importance of the uterine glands in the mammifera during gestation. Thus, the illustrious Professor Gurlt,* in speaking of the uterine glands of the mare, affirms that the villi of the chorion enter into openings of these glands, and, for that very reason, they are quite ob- vious in the gravid uterus. Colin says ? that they are the means by which the placental papille are united with the uterine mucous 1 Zusiitze zur Lehre von Baue und Verrichtungen der, Geschlechtsor- cane. Leipzig, 1846. 2 Handbuch der vergleichenden Anatomie der Haussaugethiere. Ber- lin, 1860. 3 Traité de Physiologie des Animaux domestiques. Paris, 1856. Vol. ll., p. 561. 12 UTRICULAR GLANDS OF THE UTERUS. membrane, and that this is true of almost all animals; and he quotes in support of this opinion, but not very appropriately, the views of Weber. To return, however, from assertions to actual ob- servations, Leydig recapitulated a few of those upon the uterine glands." He asserted that the mucous membrane of the uterus is of glandular structure in a great number of mammals. These glands are long and canaliculated in the mare, the sow, and the car- nivora, and very long in the ruminants. According to Barkow, they must have a very great develop- ment in the seals. Eschricht had already demonstrated their existence in dolphins. Myddleton has found them highly developed in the opossum. Leydig, who had not at first discovered them in the mole, after- wards recognized that they exist in that animal, and that they present a utricular form analogous to the glands of Lieberkuhn. In rats, instead of glands we find very distinct folds of mucous membrane. Yet, he says, considering the subject from another point of view, we may regard the spaces comprised between these folds as colossal glands. We should find the same conditions, in that case, as in the intestinal | glands of the batrachians, which consist of alveolar folds of mucous membrane, or of short sacs of consid- erable size. He affirms that the openings of these glands are infundibuliform in the ruminants; and he repeats what Malpighi had already written, — that during gestation their orifices are so dilated that they can be perceived with the naked eye. Finally, in these later times, Professor Spiegelberg,? at the close 1 Lehrbuch der Histologie des Menschen und der Thiere. Frankfort, 1857. 2 Zeitschrift fiir rationelle Medizin von Henle und Pfeufer. Band 21. UTRICULAR GLANDS OF THE UTERUS. is of some observations made upon the uterus of the ruminants, declares that the openings and the canals of the maternal cotyledons, into which the villi of the chorion penetrate, are nothing but remarkable expansions or dilatations of the uterime glands, and that they serve to establish the intimate union of the mother with the foetus. But before Spiegelberg, Bischoff had said, in speaking of the allantois of the ruminants, that, during gestation, the numerous ele- vated points upon the internal surface of the uterus, which are also observed in non-gravid cows, take on a great development, sometimes under the form of depressions, sometimes under that of rounded ele- vations with numerous excavations; that the latter appear to be formed only by the uterine utricular glands developed into tubes, into which the villi of the chorion are fitted; and that through their walls is carried on the exchange of materials between the blood of the mother and that of the foetus. This has been the condition of science upon this profound question from Malpighi’s time to our own day. The observations upon the penetration of the villi into the uterine glands have not since been confirmed, and nothing has been added to what Sharpey, Bisch- off, and Weber had taught us with regard to but one species of animal with single placenta, namely, the dog. However, the naturalist was almost forced to recognize the importance of such a conclusion, es- pecially after Gurlt had affirmed that this fact was very clear in all cases where the placenta is villous or diffused, as in the mare, and after the statements of Bischoff, and still more after those of Spiegelberg, who taught that the cotyledons of the ruminants 14 UTRICULAR GLANDS OF THE UTERUS. were only very remarkable dilatations of the extrem- ity of certain uterine glands. I regret that, in view of the order and the brevity which it is indispensable to bring into all that re- mains for me to say, I am forced, for the time being, purely and simply to negative all these observations. I shall point out the facts which have led me to this absolute negation, when I describe the means of union between the mother and the foetus in the different forms of placenta, and judgment can then be passed upon my researches and my opinion. For the present, I shall limit myself to a few ana- tomical considerations upon the utricular glands of the uterus of the different species of animals that I have been able to examine. The type of these glands does not change, in general, in the various species; but it cannot be said that there are no differences to be found. Thus, to begin with the least important, I will remark that if these glands are all formed by a canal of variable length, simply flexuous or tortuous, composed of a thin, fibrous, external membrane, and covered internally by an epithelial layer, nevertheless the thickness of the external membrane and the form of the epithelium vary in quite a remarkable manner. In some animals the glands are formed by a canal that is always uniformly spiral, as in the mare (Plate III, Fig. 1). In the cow, on the contrary, the diam- eter of the canal, as well as the form of the glands, is variable, owing to the very irregular saccate prolonga- tions, or projecting or goitre-like appendages (Plate IL, _ Fig. 2). In dogs and some other animals the very con- splcuous saccate appendages are never absent (Plate II., Fig. 1); and though they are irregular, yet, the UTRICULAR GLANDS OF THE UTERUS. 15 projecting or goitre-like form being wanting, their irregularity is less apparent than in the cow, and the term branching, which has been applied to them, is exaer (Plate Il, Fig. 1, a). In the cat the glands are pyriform (Plate IV., Fig. 2), and only upon the largest did I find any expansion or sinuous arrange- ment at their extremities. Among the ermaceade of Kurope, the utricular glands are formed by a uniform tube, which, after proceeding for a short distance from its orifice in almost a straight line, is rolled up in the shape of a ball, like the sweat glands in man. In all these animals the utricular glands le in an oblique direction, and are almost parallel to the in- ternal surface of the uterus. For this reason and on account of their length, it is often very difficult to examine one in its entire course, and to measure its exact extent. The direction of their course is also the cause of the constant obliquity presented by their orifices (Plate III., Fig. 3), which are usually tunnel- shaped (Plate II, Fig. 1, a, and Plate IV., Fig 2, a). In some other animals the opening is as round as the cavity of the gland, although it presents it- self obliquely, as in the mare (Plate II, Fig. 3). In some animals, again, the internal epithelium is paved, as in dogs and cats (Plate II, Fig. 1, and Plate IV., Fig. 2); in others it is cylindrical, as in mares and cows (Plate III, Fig. 3 ; Plate II, Fig. 2; and Plate V., Fig. 2). Of the utricular glands of the uterus in woman some are simple, others branching; their external membrane is excessively thin, and some anatomists, after M. Velpeau, call it anhistous or formless ; the in- ternal epithelium is delicate and cylindrical. It is not as easy to observe them as it isin animals. According 16 UTRICULAR GLANDS OF THE UTERUS. to Hirtl, the mucous membrane of the uterine cavity would be represented by these tubular glandules, united by a connective tissue, and by capillary blood- vessels. Yet sections of the glands, parallel or trans- verse to the mucous membrane of the uterus, have shown me that in the human species they are not so closely pressed against each other as is generally claimed, and that they were drawn from the imag- ination rather than from nature in the memoir of Weber. This has not, however, prevented Weber’s representation from being reproduced in a very great number of recent works upon human and compara- tive anatomy and physiology. In all animals, during gestation, the uterine glands increase in volume, and the epithelium becomes more transparent and more delicate. Anatomists and physiologists have accepted the opinion of Sharpey, confirmed by Weber and Bisch- off, that in the cat and dog there exist two species of uterine glands, the simple and the branching, to which some have been inclined to attribute very dis- similar functions: to the simple, that of secreting the uterine mucus; to the branching, that of contribut- ing to the nutrition of the foetus. It was very in- teresting to me to verify such an observation ; how- ever, as I have before stated, by vertical sections of the uterus only transverse cuts of the glands could be obtained. But it occurred to me that, in order to secure some simple glands, crypts, or follicles, and portions of the branching ones large enough for ex- amination and comparison, it would be necessary, perhaps, to remove, by the aid of a brush and by 1 Manuale d’ Anatomia Topografica. T. ii., p. 112. Milan, 1858. UTRICULAR GLANDS OF THE UTERUS. LT several washings, the surface layers of the epithe- lium of the mucous membrane; then to lift up with the forceps the most superficial envelope of the mu- cous membrane thus denuded, and cut this same en- velope at its base, that it might be stretched upon glass. I could then, with the aid of the microscope, easily discover in this thin layer what it was impor- tant for me to observe. ‘The experiment succeeded, and it will always be of the greatest value to those who shall desire to examine the uterine glands of animals. By this means, I have several times ob- tained entire utricular glands of the uterus of the dog as they are represented (Plate IL, Fig. 1, a, a); but all the experiments that I have repeated by this same method have never enabled me to find a single simple gland or crypt in the uterus of the dog. Since I often obtained complete utricular glands, I ought also to have found, and much more easily indeed, the short glands or crypts, if they had really existed. While studying in the same manner the uterine mucous membrane of the cat, I thought at first that I recognized the two species of glands of Sharpey and Weber; but on closer examination (Plate IV., Fig. 2, 6, 6) the volume and the variable length of the glands seemed to indicate varying degrees of de- velopment or difference of size in the same species of glands rather than to establish two distinct species of glands. Can it be possible that the number of ges- tations should have sufficient influence to account for the existence or absence in the dog also of what I had observed in the cat? Can it be possible that in certain individuals only the volume of these glands should be variable to such a marked degree? To 9 di 18 UTRICULAR GLANDS OF THE UTERUS. solve these questions, it would be necessary to devote one’s self to a great number of comparative researches, which I have not been able to do. But the observa- tions which I have adduced, although limited, suffice absolutely to refute the assumption of the capital fact of the existence of two distinct species of glands in the uterus of the dog and of the cat, — an alleged fact from which such grave physiological conclusions had been deduced by attributing to each species very dif ferent functions. But if we cannot admit two species of uterine glands in the dog and the cat, they are found and easily observed in other species, — for ex- ample, in the cow and the sheep. The demonstration of them is positive and easy, by cutting transversely the mucous membrane which covers the rudimentary cotyledons of the non-gravid uterus of those animals; we cannot remove the mucous membrane at the point indicated in the same way as in the dog or the cat. Until our own day, the existence of the crypts or sim- ple glands (which to avoid ambiguity I shall hence- forth call simple glandular follicles), had escaped the notice of observers. They are in reality very numer- ous, and are found agglomerated in the rudimentary cotyledons. Although they are not wanting in the rest of the uterine mucous membrane, 00; are there fewer and more disseminated. In vertical and transverse sections made near the in- ternal surface of the cotyledons of the cow (Plate V., Fig. 2), the follicles are almost always seen cut across; this, in my opinion, signifies that they have a sinuous form, and that they also, like the utricular glands, have an oblique direction. In a few cases, only, do we succeed, by vertical incisions, in cutting these fol- Een aaa ee Ln cin Be i Poni nin na" I UTRICULAR GLANDS OF THE UTERUS. 19 licles vertically also; they appear then under the form of extremely thin and irregular clefts or fissures. ‘They differ essentially from the utricular glands in that they are very much shorter and more attenuated, and because their internal epithelium is paved instead of being cylindrical, as in the utricular glands (Plate V., Fio. 1,.a). They both have one feature in com- mon, that is, they increase in volume during preg- nancy. In length, as well as in volume, the follicles vary sensibly among themselves. Those which are found agglomerated in the rudimentary cotyledons, and which are only the pedicle of the maternal coty- ledon in the gravid uterus, as well as the utricular glands which traverse it, probably pour out the fluid secreted at the base and in the interior of the mater- nal cotyledon, or glandular organ of new formation. In both it is very difficult clearly to distinguish the orifice. Near the base of the glandular organ, seg- ments of these follicles are often visible (Plate VI., Fig. 1, m), and what is most remarkable is not so much the increase in volume as the change in the secretion. In fact, their internal surface is no longer covered with pavement epithelium, and we discover upon it very diaphanous oval cells. It is difficult to say what their office may be; yet their increase in volume during pregnancy, their agglomeration in the cotyledons, and their change of secretion lead us to suppose that they are charged with an important func- tion analogous to that of the utricular glands. At all events, what I have said upon the simple glandu- lar follicles of the uterus of the cow, and especially those of the places where the placenta is formed, is sufficient, I think, to exclude the doctrines of those 20 UTRICULAR GLANDS OF THE UTERUS. who taught and believed in the existence of short or simple glands in the uterus of animals, attributing to them the very simple function of secreting the uterine mucus. In the centre of the uterine depressions which con- stitute the rudimentary cotyledons in the sheep we may observe, as I have said, numerous simple glandu- lar follicles. The distribution of these glands differs in the sheep, however, from that which we find in the cow. In the rudimentary cotyledons of the non-gravid uterus of this latter animal the openings of the utric- ular glands are intermingled with those of the follicles (Plate V., Fig. 2); while in the rudimentary cotyle- dons of the sheep the utricular glands open around the elevated border which circumscribes the cotyle- dons, and in the central depression or concavity we see only, in very great numbers, the simple follicles. I have several times stated that the utricular glands, as well as the follicles, increase in volume during pregnancy ; but though this observation may be traced back, as far as the glands are concerned, to Malpighi himself, the measure of their increase I have not found indicated by any one. The illustrious Professor Panizza! injected the utric- ular glands through their orifices, and he says that they are formed by a slender canaliculus, which is divided into two or three other smaller canaliculi, serpentine and goitre-like, terminating, after a course of three or four lines, in cu/s-de-sac. But he does not say whether he made the injections with the gravid or non-gravid uterus. It is very probable that it was during gestation, when the increase in volume of the 1 Sopra l’Utero d’Alcuni Mammiferi, page 10. Milan, 1866. UTRICULAR GLANDS OF THE UTERUS. ZI. glands renders the operation more easy; this, how- ever, we cannot assert positively. In the cow, the glands vary in length and in breadth in the gravid as well as in the non-gravid uterus, and the difficulty experienced in removing them entire and in sufficient numbers has prevented | me from establishing an approximate measure of their length. I have therefore contented myself with noting the differences to be met with in meas- uring their transverse diameter, the sections in this direction being made, as I have said, quite easily both in the gravid and non-gravid uterus. I have always tried to measure them near their opening into the cavity of the uterus, because at that point we do not find the total or partial dilatations which are met with along the course of the uterine glands of certain animals, as in the cow, and which would be a source of error. The following are the results which I have ob- tained: In the non-gravid uterus of the mare, the transverse diameter of the utricular glands, the thick- ness of the walls included, varies from 0.04 to 0.05 millimeters. In the uterus of the mare at term I have found the diameter to be from 0.05 to 0.06 mil- limeters. In the gravid uterus of the cow, these glands reach a much larger development. For greater exactness, I took, in this animal, measures of the transverse sections upon the cotyledon of non-gravid cows, and upon the pedicle of the cotyledon of gravid cows. In the first case, the transverse diameter, the wall in- cluded, was from 0.09 to 0.10 millimeters ; in the sec- ond case, in the third month of gestation, it increased from 0.14 to 0.16 millimeters. 229) UTRICULAR GLANDS OF THE UTERUS. I further measured the simple follicles from the same localities. In the non-gravid animals, the diameter of the follicles being, as we have seen, nor- mally very variable, it changed from 0.02 to 0.04 mm.; in the gravid ones, from 0.04 to 0.08 mm. We shall see, further on, how and why the inter- nal cavity of the uterus in woman and in the mare ought, strictly speaking, to be considered as covered with a mucous membrane. At present we can admit the universal opinion that the uterine mucous mem- brane presents remarkable differences in the different species of animals. This being granted, we shall be permitted to quote the peculiarities we meet with in the uterine mucous membrane of rabbits, in which certain learned anatomists, like Bischoff, are not sure of the existence ot the utricular glands, while others, like Leydig, have denied their existence in some of the rodents, as the rat, for example. The mucous membrane of the non-gravid uterus of the rabbit appears to be formed of very delicate follicles, which might be called mucous, pressed close together, having a very narrow cavity or canal, vary- ing in length from 0.05 to 0.08 mm. It was, perhaps, these follicles that Leydig, as I have before stated, compared with the intestinal glands of Lieberkuhn in the mole, without finding any essential difference be- tween the latter and the very elevated folds that are visible in the uterine mucous membrane of the rat. The opinion of Leydig receives strong confirmation when we examine comparatively the uterine mucous membrane of a gravid rabbit and the portions where no placenta has been formed. Here we meet large projecting linings or folds of the mucous membrane, UTRICULAR GLANDS OF THE UTERUS. 23 where the glandular follicles that I have mentioned have really acquired a colossal development. I shall speak of this more at length in treating of the formation of the placenta. For the present, I will simply observe that in examining the uterus of a pregnant rabbit, in which the upper portion of one horn had remained empty for about four centimeters of its length, I found the mucous membrane of this portion of the uterus covered with follicles of from 0.02 to 0.03 mm. in length, and 0.04 mm., or a trifle more, in width. They all had a much larger orifice, varying from 0.04 to 0.08 mm. In the largest, the opening, or central cavity, was 0.02 mm. in diameter ; the thickness of the wall and of the internal epithe- lial layer measured 0.03 mm. It was easy for me to ascertain these facts by lift- ing and detaching folds of the mucous membrane in the manner I have explained. By this means, we are assured of a very important fact, namely, that there exist no utricular glands in the uterus of the rabbit; while, from the vertical sections of the gravid and non-gravid uterus of this animal, there always necessarily remains something of uncertainty and doubt. We do, indeed, by the aid of such sections, easily see glandular tubes, but they are cut trans- versely and a little removed from each other (Plate VIL, Fig. 4, d, d). Without the method I have described, it was im- possible to form an idea of the length and distribu- tion of the so-called glandular tubes, which seem very few and scattered, when they are really only portions of the bases of the follicles, divided transversely, and included in the cutting of the preparation. 24 UTRICULAR GLANDS OF THE UTERUS. This explains the doubts of some, and the con- tradictions between those who maintained and those who denied the existence of the utricular glands in the uterus of rabbits. But what is of more im- portance is the further demonstration that the uter- ine utricular glands are really wanting in some of the mammalia. In that case, the mucous crypts or simple glands increase in volume during pregnancy in a truly extraordinary manner, and might lead us to suppose, with some appearance of reason, that they fulfill the function which belongs, under such circumstances, to the utricular glands and the simple follicles, when those organs are not lacking. From the very fact of the absence of the utricular glands, one can argue the great importance which they have during the period of gestation; but it is always very © difficult to say precisely what their office 1s. The numerous facts which I have just quoted give strong probability, I think, to the opinion expressed with fewer data by Eschricht, and adopted by several illustrious physiologists, namely, that these glands, to which I shall add the simple follicles, elaborate, dur- ing gestation, a fluid destined to furnish some ele- ments for the nutrition of the foetus, particularly when the organs which are charged with that office, or the villi of the chorion, are not fully developed. That both produce, in great measure, in the time of non-gestation, the fluid known under the name of uterine mucus is very probable; but what I emphat- ically assert is that there do not exist in the uterus of mammals two species of glands, distinct in form, volume, and office, as many authors have advanced. In speaking of the human decidua, I shall show UTRICULAR GLANDS OF THE UTERUS. 29 that it may be considered as a product of exudation, due for the most part to the utricular glands, and that the numerous openings which perforate it ob- liquely precisely indicate the mouths of those glands, which remain open in the decidua for the continual passage of the materials elaborated by the glands. The same thing, though with entirely opposite re- sults, is clearly seen in the foetal envelopes of the cow, most anatomists denying the existence of the uterine or true decidua in that animal. It does exist, how- ever, and it is easily seen in preparations hardened in alcohol or chromic acid. It is met with in the form of a yellowish pellicle, composed of epithelial cells irregularly stratified and covering the whole external surface of the chorion. The principal dis- tinction of this epithelial layer, which represents the human decidua, is, that instead of adhering to the in- ternal surface of the uterus, it adheres to the chorion, towards which is directed the product of the uterine glands. The result is that, instead of the cavities or sluices which we perceive in the human decidua, we find in the decidua of the cow, at the places corre- sponding to the uterine glands, small scales in the form of lids (of a yellowish, transparent substance, hard, and resisting the action of acids and alkalies), which infiltrate into the chorion itself, and there be- come assimilated. Burkhardt* was the first to speak of this, and no > 1 « Quum igitur uterum a chorio removissem, propius lente vitrea ar- mato oculo inspexi, et corpuscula minima lutea chorio inherentia ex oculis vasorum spiralium recedere observavi. Simula ex vasorum orificiis hee corpuscula remota fuerunt : guttule humoris lactei ex vasibus spirali- bus extillaverunt.’? (Observationes Anatomic de Uteri Vaccini Fabrica, page 24. Basle, 1834.) 26 UTRICULAR GLANDS OF THE UTERUS. one has repeated his observation. Now, on examining these scales, I have been able to remark that they are formed from a thin and larger lamina which rests upon the chorion, and that on the part facing the uterus, opposite to the orifice of the glands, there is upon the lamella an ovoid protuberance of the form of a large nut, sometimes smooth and with yellowish central granulations, sometimes irregularly ridged and granulated. The size of these solid scales or lids is variable; some are rounded, and others oval or elliptical. The total diameter of those which are rounded exceeds somewhat 0.10 mm.; and the central oval elevation is 0.06 mm. in its greatest diameter. Among those of an elliptical form, the largest meas- ured 0.30 mm. in their main length, and 0.16 mm. in breadth. The central elevation was 0.24 mm. in length, and 0.10 mm. in breadth. What I have said thus far will suffice for the uter- ine glands and their functions. But it remains for me to speak much more at length of the glandular organ of new formation in the uterus of the mam- mifera and of the human species, which always forms, as I have already said, the maternal portion of the placenta. CHAPTER III. ON THE GLANDULAR ORGAN, OR MATERNAL PLACENTA, IN ANIMALS WITH A VILLOUS OR DIFFUSED PLA- CENTA. THE ancient writers upon comparative anatomy maintained the absence of the placenta and of the cotyledons in the gravid uterus of certain animals, such as horses and swine. Modern writers have added that the villous or diffused placenta, as it is now called, is also met with in the camel, the drome- dary, the llama, and, according to Miiller, in the ce- taceans.! A new comparative study of the gravid uterus of these animals may lead to the discovery of quite interesting anatomical differences. It was long ago remarked that in the sow the papille (villi) of the chorion, instead of being short, very close together, and almost regularly distributed over the whole surface, are united in the form of pencils or tufts, the papille of the intervening spaces being much more thinly scattered. This condition constituted, it was thought, a transitional form be- tween the diffused placenta and the agglomerated placenta of the ruminants. For the time being, I shall examine only the villous or diffused placenta of the mare, not having been able to extend my ex- 1 Miiller: Manuel de Physiologie, t. ii., p. 731. Paris, 1851. ? Colin: Traité de Physiologie comparée des Animaux domestiques, b. il., p. 560. Paris, 1856. 28 ON THE GLANDULAR ORGAN. amination to that of other animals. Fortunately, it is claimed that the placenta of the mare presents a greater simplicity than that of the sow, and it should consequently be selected as a type for the observa- tions I am about to offer. On comparing the opinions that the science of the ancients has bequeathed to us upon this subject, we find that the teaching nearest the truth is due to our own Ruini. In the description of the placenta or secundine of the mare, he expresses himself as fol- lows: — “Upon these foetal envelopes exists the red flesh, spongy and thin, which is met with in the matrix and the horns of the uterus of gravid mares. It is formed by the first blood of the uterine veins, which emerges almost thickened and curdled from their open extremities over the internal surface of the uterus. Its form is that of the uterus itself, because it is disseminated over the whole surface of it. It differs from the form of the placenta or secundine in woman, the latter being round like a cake.” * As a result of my observations, I am persuaded that these words of Ruini relate really to the gland- ular organ, which I shall soon describe, and which is formed over the whole interior surface of the uterus. I would not, however, deny that by the words “carnaccia rossa e spugnosa” he may have intended to speak of the villi of the chorion, which were after- wards considered by authors as constituting, in them- selves alone, the placenta of the mare; or, he may have referred to these villi and to the glandular 1 Dell’ Anatomia e delle Infirmità del Cavallo, Lib. IV., cap. xii. (Anatomia). Bologna, 1596. ON THE GLANDULAR ORGAN. 29 organ or maternal portion of the placenta both to- gether. Eight years after Ruini, the celebrated Fabricius of Acquapendente, in his memorable work De For- mato Foetu, considered the villi of the chorion as rep- resenting the placenta in the mare. This opinion was known and accepted by the illustrious Albert Haller, who, in the development of the idea, asserted that “in omnibus omnino quadrupedibus chorion repeti- tur, etiam in lis, quibus vera placenta vix tribui po- test, ut in sue, ut omnino videatur naturam quad- rupedum posse placenta carere, chorio carere non posse.” ? Fabricius had also made another observation, which deserves special mention, both because he published it for the first time, and because it was afterwards either forgotten or repeated in a vague and uncer- tain manner. The observation is this: The small projections formed by the villi of the chorion enter into as many corresponding cavities of the uterus: “ Minima et innumera tubercula per chorion dispersa et sese quasi mutuo tangentia, que in cavitates, sibi in utero respondentes, intrant, quae sane carnea sub- stantiae vicem subeunt,” 5 Now, if we seek for the developments of this dis- covery, from Fabricius to our own time, we shall find nothing satisfactory; for it has been either simply repeated or entirely forgotten. “The chorion of the pachyderms,” -writes Baér, 1 Padua, 1604. 2 Elementa Physiologie Corporis Humani, t. viii, p. 185. Berne, 1766. 8 Hieronymi Fabricii ab Acquapendente: Opera Omnia, Anatomia et Physiologia. De Formato Fetu. Pars 11, page 89. Leyden, 1737. 30 ON THE GLANDULAR ORGAN. “is covered with villi, which do not increase very much in size; they correspond to innumerable de- pressions upon the internal uterine surface, disposed like the cells of a honeycomb, each of which receives a villus of the chorion.” ? . Some years afterwards, Miller, instead of adding anything clearer and more precise, was even more vague and uncertain than Baer. He says? that in the pachyderms the foetal placenta extends over the entire surface of the chorion, and that the maternal placenta is also distributed over the internal face of the uterus, which acquires a cellular texture and presents numerous depressions destined to receive the chorial villi. My unsatisfactory retrospective study does not stop here. The ancients knew that the union of the chorion with the uterus, in the mare and the sow, takes place only during the last months of gestation. Yet not only was this observation forgotten (and it assumes to-day a very great importance in connec- tion with the new formation of a glandular organ over the whole internal face of the uterus, which I ‘am about to demonstrate), but things have been taught which are directly contrary to truth. The first who drew the attention of anatomists and physiologists to this highly important fact was the Englishman Needham,’ who, after having affirmed that in the pregnant sow the chorion adheres in no manner to the uterus, up to the middle period of 1 Untersuchungen iiber die Gefisseverbindung zwischen Mutter und . Frucht in den Saugethieren. Leipzig, 1828. 2 Manuel de Physiologie, t. ii., p. 732. Paris, 1851. 8 Disquisitio Anatomica. De Formato Fetu, page 177, etc. London, 1767. ONY THE \GLANDULAR'ORGAN. ... 51 gestation, and that towards the end the projections or tubercles of the chorion adhere to it slightly, adds : — “ Equa quoque, ut sepius innui, prioribus mensibus fere eodem modo se habet et utero nusquam coheeret. Donec post aliquod tempus tubercula carnea exigua appareant orobi magnitudine. Hc paulatim augen- tur, invicem continuantur et digitulos (non glandu- loso corpore utero adnascenti!) sed ipsi uteri mem- brane interiori, satis insignes inserit. Ut revera con- tinuata quedam placenta per totum chorion extensa videatur, vel potius chorion ipsum ex membrana in placentam mutatum.” And a little further on, at page 181: “Tandem in posterioribus mensibus eo ventum erit, ut chorion, notabili jam crassitie insigne, placentam utero continuatam repreesentet, surculosque infinitos totidem venulis turgidos, uteri tunice® inte- rior! immittat.” Snape” observed further that the chorion of the mare adheres to the inner membrane of the uterus only towards the end of the sixth month, and that, in the last months of pregnancy, the villi of the chorion so augment in volume that it seems to have lost the appearance of a membrane, and to have be- come a placenta. : Wepfer* confirmed these observations, accrediting them to Graaf. But that celebrated anatomist really 1 In speaking of the sow he had said: Nulle hic glandule, nulla placenta.” (Loc. cit.) 2 Anatomy of the Horse. London, 1606. 8 This quotation was taken from the French translation of the work of Snape, by Garsault: L’Anatomie générale du Cheval, page 32. Paris, 1732. * Ephem. Natur. Curios. Dec. 1, An. 1. 8 obs., p. 129. DR ON THE GLANDULAR ORGAN. did nothing but repeat observations already published by others, as we have seen. Haller afterwards coòrdinated, so to speak, these scattered observations, but without adding anything of his own, and even leaving uncertainties, which must be kept in mind. Thus, after having said : — “Qui equo et sui nullam placentam esse docent, ii prima tempora foetus sola describunt, in quibus sola chorii membrana uterum sublinit. Nam etiam in his animalibus placenta sensim subnascitur, et in equo quidem chorion ex vasis nunc numerosissimis congesta in unam continuam placentam abit que cum utero confervet.” He adds a little further on :3 — “ Quee enim animalia eam conjunctionem [the union of the uterus with the placenta] habent leviorem lis etiam plus de chorii natura manet, et minus cum placenta humana convenit, ut equo et sui, et excusari possunt veteres, qui placentam pro crassiori chori particula habuerunt.” I will not deny that the old writers were excusable, but it seems to me that this illustrious physiologist has simply repeated what they had said. All of them thought that the placenta was formed by the villi of the chorion. The same uncertainty, although more marked, can be traced back to Fabricius, who, with antique simplicity, confesses his own ignorance : — 1 « In suibus vero per totam gestationem placenta nulla deprehenditur, at tantum chorii crassities quedam apparet: idem quoque in equibus primis gestationis mensibus observari dicitur, donec post mediam gesta- tionem in chorio exigua tubercula carnea excrescant, quorum beneficio illud utero cohereat.” (R. Graaf: Opera Omnia, page 207. Leyden, 1678.) 2 Idem, Physiol., t. viii., p. 238. Berne, 1766. 8 Idem, page 226. ON THE GLANDULAR ORGAN. 33 “In porcis autem et equis, quibus carnea moles nulla conspicitur, quid dicemus? Non certe quod aliquando Arîstoteles precepit ut rem obscuremus, cum ignoramus: sed magis cum aliqua concinna sen- tentia ignorationem tegamus: que est, ut in porcino et equino foetu carneam substantiam ut in ceteris non observemus, quoniam Deus providentiam et po- testatem suam multarum rerum mirabili varietate voluit ostendere.” A little further on he says also: — “ At cur equinus et porcinus foetus ea destituantur, nihil habeo quod asseram. Nisi forte dicamus, non prorsus deficere, cum exterius per totum chorion ex- igua, imo minima, innumeraque tubercula, quasi se tangentia conspiciamus, cavitates illas in utero re- spondentes intrantia. Cur vero in equino et porcino foetu ita habeant, explicet ille qui me felicior tanta- rum potuit rerum cognoscere causas.” ! All these observations upon the gravid uterus of the mare, which to-day may be called ancient, have not, since their codrdination by Haller, been devel- oped as they deserved to be. Succeeding authors and the moderns content themselves with the statement that the uterme mucous membrane of the pregnant mare is tumefied ; or, at most, like Baer and Muller, reproduce under a new but incomplete aspect what Fabricius and Needham had more clearly stated. None of them has ascertained or shown the real nature of the “carnaccia rossa” which was formed over the whole internal uterine surface, as was first pointed out by Ruini. The moderns, in general, have admitted the idea ! Hieronymi Fabricii ab Acquapendente, op. cit., page 89. 3 34 ON THE GLANDULAR ORGAN. that the villi of the chorion constitute of themselves è the placenta of the pachyderms, disseminated or dif- fused over the whole surface. The opinion, incor- rect indeed, of the celebrated Gurlt, that in those animals the chorial villi penetrate directly into the | utricular glands of the uterus, did not serve to change | this notion. If the opinion of Gurlt had been correct, it would | at most have confirmed, as to those animals, the ob- | servations of Sharpey and Weber upon the penetra- | | tion of the extremities of some of the villi into the | | first portion of certain uterine glands, where the pla- i centa is formed. I need only quote a few words of Colin to show how entirely forgotten in our own day have been | | the anatomical truths which I have just presented | to you, as taught, though incompletely, by ancient | writers: — | “ The mode of union of the placental papille (villi) | with the uterine mucous membrane is nearly the | same in all animals, whatever may be the form of || the placenta. On the uterine surface the mucous | | membrane presents, according to the careful obser- | vations of Berres and Weber, several kinds of folli- | | cles: some, broad and shallow, seem destined for the secretion of the mucus; others, very large and with | numerous ramifications, destined to receive each a Ht placental papilla and its various filaments. These follicles have, among the ruminants, enormous open- | wt | ings.” 2 i | © i Il 1 Handbuch der vergleichenden Anatomie der Haussiugethiere, page (N | 431. Berlin, 1868. | 2 Traité de Physiologie comparée des Animaux domestiques, t. ii., p. 561. Paris, 1856. ON THE GLANDULAR ORGAN. 35 . Unfortunately, the conclusion of these historical researches is not encouraging. After more than two centuries, what little of truth was known has been forgotten; while new observations have been pub- lished, either untrue or imperfect, which have led us to a series of errors that I have summed up in the short quotation from Colin. The comparative examination of the mucous mem- brane of the gravid and non-gravid uterus of the mare is of the greatest interest to anatomists and physiologists, because it reveals in all its simplicity and with clearness the constant double structure of the placenta. On comparing the mucous membrane of a non-gravid uterus with that of a gravid uterus almost at term of this species of animals, we remark, even by simple external and superficial observation, certain differences of form and color. In the non-gravid uterus, the mucous membrane is smooth and velvety, of a rose color, inclining to yellowish ; here and there it is doubled over into large and soft folds. In the gravid uterus, on the contrary, the folds are wanting, and over the whole surface of the mucous membrane are scattered vermi- form projections, winding closely against each other, of a very intense, deep red color, tending to violet; the surface, instead of being smooth, has a swollen appearance, and, as we observe it, we cannot help thinking of the “carnaccia rossa e spugnosa” of Ruini. On cutting vertically portions of the gravid uterus at an advanced period of gestation, and comparing them with similar sections in the non-gravid uterus, we perceive, even with the naked eye, that the mu- 36 ON THE GLANDULAR ORGAN. cous membrane, which is scarcely distinguishable in the latter. is considerably enlarged in the former, and that it constitutes a uniform layer, varying from a millimeter and a half to two millimeters in thickness, of a yellowish-red color, and on the interior of the cut surface having a swollen appearance. By care- fully disengaging the chorion, we easily succeed in seeing that the numerous and closely-packed villi which cover it, enter into the thickened layer, into which the mucous membrane seems to have been transformed. It is extraordinary that very respectable anato- mists and physiologists should have contented them- selves with these simple and superficial observations, and not have carried their researches further. I have until now added nothing of my own to what Fabri cius and Needham had taught, and von Baer and Miil- ler had repeated with somewhat less completeness. But microscopic examination quickly revealed to me the easy and positive explanation of these transfor- mations, which I shall now briefly point out. In Plate IIL, Figs. 2 and 1, I have represented ver- tical sections of the gravid and non-gravid uterus of the mare, very slightly magnified, in order to show, at first sight and a little more clearly, the differences which, as I have already said, are visible even to the naked eye. The dark line (Fig. 1, a, a) represents the epithelial layer which covers the whole internal surface of the non-gravid uterus in the mare. The letters 6, 5 indicate the utricular glands; some are entire, while others are cut in different directions. The magnifying power employed is so slight that we cannot distinguish any element of the sub-mucous, ON THE GLANDULAR ORGAN. 37 cellulo-vascular layer, in which the glands are im- bedded. Fig, 2 represents a like vertical section of the gravid uterus in the same animal; and what first strikes us is the increased size of the line marked a a, in the preceding figure. It is no longer a dark line, in which the cellular elements that compose it are not apparent, but a layer uniformly undulating, and formed by masses resulting from the union of small sacs or follicles pressed closely together (a, a). The masses are separated from each other by the secre- tory canals of the utricular glands (4, è), which, by reason of the thickness of the sub-mucous layer and their own increase in volume, are more easily cut transversely in the gravid uterus. From these few features that I have pointed out, there arises a two-fold and very important question : What is this uterine mucous membrane in the mare, and what portions ought to be comprised under that denomination? What parts of the mucous mem- brane undergo transformation, and thus give rise to the differences we have remarked ? In order to determine of what this mucous mem- brane consists, I must first of all recall the fact, that for a long time anatomists were uncertain whether the internal surface of the uterus in woman was or was not covered with a mucous membrane. Bischoff, in his treatise upon the development of the ovum, touched upon this question in speaking of the mem- brana decidua, and he says: “If the admission of a mucous membrane in the uterus of woman implies that it may, by the scalpel, by maceration, or by any other operation, be distinguished and separated into a8 ON THE GLANDULAR ORGAN. an internal layer, special and membraniform, as in the majority of the mammals, it must be allowed that the uterus of woman has no mucous membrane ; for even with the thinnest vertical sections, and with the aid of the microscope, there is nowhere visible even the trace of such a layer distinct from the uterine parenchyma.” Then he adds: “ If we consider the nature of the internal surface of this organ, we see that it has strong resemblances to a mucous surface.” It seems to me, to tell the truth, that Bischoff, in this way, has evaded rather than resolved the ques- tion. And what has been said concerning the uter- ine mucous membrane of woman may be also asserted in reference to the gravid or non-gravid uterus of the mare. With regard to this species of animals, we should fall into even greater contradictions; for in deciding that the uterme mucous membrane in the gravid mare is formed of the layer of glandular fol- licles, of which I have before spoken, it would also be necessary to affirm that in those animals the uterus is covered on its internal surface with a mucous membrane during gestation only, and that it is wanting in the non-gravid uterus, unless we chose to give the name of mucous membrane to a simple epithelial layer, and then the uterine mucous mem- brane would exist in the mare when not pregnant, and would be lacking during pregnancy. Now, the peculiarities that I have mentioned as existing in the uterine mucous membrane, when treating of the glands of the uterus, will enable me, I think, by again referring to them, to answer this question, which has some interest for anatomy as well as for physiology, ON THE GLANDULAR ORGAN. 39 and which has a special interest for me, forced as I shall be, constantly, to speak to you of the mucous membrane of the uterus. The solution of this problem, at first sight very complex and difficult, if we limit our researches to the human uterus, becomes, on the contrary, very easy, in my opinion, if we call to our aid compara- tive anatomy. Indeed, what composes the uterine mucous membrane in the animals in which it is ad- mitted by all without dispute? It is claimed that the mucous membrane exists when, without the aid of any method of dissection, a membraniform layer can be easily lifted from the internal surface of the uterus; it is claimed with yet more assurance when this layer rises under the form of folds or plaits, more or less apparent. But appearances should not be confounded with reality. In examining, with the aid of the microscope, the internal surface of the uterus of the mare or of woman, where a true mucous membrane, in the anatomical sense of the word, does not exist, and a festooned fold of the uterus of a rat, in which the existence of the mucous membrane is not disputed, the observer notes no real difference between their histological elements. It has already been said that in the mare it is an epithelial layer which rests upon a soft connective tissue of the internal uterine surface, while in woman the same thing is observed, with this sole difference, that the connective tissue is more dense, more com- pact, and more adherent to the epithelial layer. But in the rat the same thing holds true also, with this one peculiarity, that the connective tissue rises from 40 ON THE GLANDULAR ORGAN. the surface of the uterus, and produces fringes and festoons of the mucous folds. This is so true that on removing the connective tissue of one of these folds, so as to loosen the folds and festoons, we find the identical constitution of the parts which form the mucous membrane of the uterus of those animals in which, as well as in woman, the existence of this membrane is denied. I have already mentioned the fact that in the epithelial layer which covers the in- ternal surface of the non-gravid uterus in the rab- bit we see small, shallow depressions, or very simple glandular follicles. Such are the principal anatomical differences of structure in the uterine mucous membrane that I have been able to detect in the animals I have ex- amined, or that I have found to be indicated by the most celebrated anatomists. But, instead of deny- ing, after the study of these facts, its existence in woman and in certain animals, and admitting its pres- ence in others, it seems to me more logical and more in conformity with the truth, to affirm that the sim- plest form of the mucous membrane is represented in woman and in the mare by an epithelial layer; that its structure does not change essentially when the sub-epithelial connective layer is more or less soft, or when it rises above the level of the internal surface of the uterus in the form of folds and fes- toons; and that, further, the greatest apparent com- plication to be observed in this membrane is found in the epithelial depressions which we remark in cer- | tain cases, but these, even, lose their seeming im- portance when, with good reason, as I have tried to demonstrate with Leydig, we consider the large vi ec La Na, E i a = x iam e y > 1 i LITTA HI ON THE GLANDULAR ORGAN. 41 folds of the mucous membrane as colossal glandular follicles. Hence follows, as a consequence, the con- firmation of the idea that a pellicle (velamento) rep- resents the simplest and most fundamental form of the mucous membrane which lines the inner surface of the uterus of all mammals, the human species in- cluded, and that this form is modified, without radi cal change, in the distinctive appearances observed in the different species of animals.! Thus, it seems to me, is more clearly defined the somewhat vague opinion of the majority of anato- mists, who, while admitting a mucous membrane in the uterine cavity, have claimed that it is insepara- ble from the subjacent cellulo-vascular tissue, and not perceptible even with the most powerful means of microscopic observation. This, strictly speaking, amounts to the assertion, “ It exists, though we are not able to see it.” . The uterine mucous membrane, compared by Bisch- off with other mucous membranes of the animal structure, from a physiological point of view and in relation to other functions, presents differences much more important and much more essential, physiolog- ically speaking, which distinguish it from all other mucous membranes. The most fundamental of all, is the marvelous transformation which it undergoes, either at a fixed point, or over its whole extent, dur- ing pregnancy, in order to give rise, always and un- der all circumstances, to the neoformation of a tran- sitory glandular organ, constituting the maternal part of the placenta. I shall now limit myself to the explanation of what 1 See Appendix. 42 ON THE GLANDULAR ORGAN. takes place over the whole internal surface of the uterus of the mare during gestation, and I will begin with the exposition of this very important phenom- enon when fully developed, that is to say, when preg- nancy has arrived at term. The part which I have heretofore said had a tomen- tose appearance, the “carnaccia rossa” of Ruini, or the tumefied mucous membrane of the moderns, with its numerous depressions, is no other than a glandu- lar organ of new formation, constituting in the mare the maternal portion of the placenta. In Plate IV., Fig. 1, I have represented an entire follicle, from a vertical section of this glandular organ, which is in connection with the villi, the villi being also con- nected with the chorion. In Plate V., Fig. 1, I have reproduced a transverse-oblique section of the same glandular organ, to exhibit more clearly its intimate structure. The new glandular organ, which arises from the sub-epithelial connective tissue of the whole surface of the uterus, is formed by the aggregation of an in- finite number of simple glandular follicles, of which a few only have a double and even a triple cul-de-sac (Plate:N field, ao): The type of these follicles seems to be single as to form, and the bifurcation of the base of some among them appears to arise from the blending of two of these follicles which are pressed close together. Their average length is, as I have already stated, from a millimeter and a half to two millimeters. The diam- eter varies according as the measurement is made at the base or at the orifice, for they are pyriform. At the apex, or a little below the orifice, which re- ON THE GLANDULAR ORGAN. 43 sembles a small tunnel (Plate IV., Fig. 1, 7), they measure three one hundredths, towards the middle portion four or five one hundredths, and at the base from eight to twelve one hundredths of a milli- meter. The sub-mucous connective tissue proliferates and is found interposed between the follicles, so as to fur- nish a wall to the external membrane of each one of them. In proximity with the utricular glands, the connective tissue develops more abundantly in the form of interposed pyramids (Plate V., Fig. 1, c, c), and it accompanies the glands as far as to their open- ing into the internal surface of the uterus, and pre- cisely to the plane where we find the orifices of the follicles of new formation. From these pyramids di- verge as many septa, which communicate with the connective tissue surrounding each follicle. In the centre (Plate V., Fig. 1) we see one of these pyra- mids cut transversely, in the midst of which appears a venous vessel (4), and two utricular glands, also cut transversely (7, f ). The whole internal surface of the glandular follicles of new formation is covered with pavement epithe- lium, which is more easily distinguished in the trans- verse sections (Plate V., Fig. 1, 5, 5, è) than in the lon- gitudinal ones (a, a). From the uterus extends a rich vascular net-work, which has a very peculiar arrange- ment. From several tranks (Plate IV., Fig. 1) ram- ify smaller trunks or loops, assuming the form of a brush, which traverse the spaces between follicle and follicle from their base to the extremity (J, 2). From the stems of these loops diverge other lateral vessels (72, m), which anastomose with each other, and 44 ON THE GLANDULAR ORGAN. go to make up the dense vascular net-work which sur- rounds each follicle. The net-work is so thick that it is not rare to find entire portions of it in the transverse incisions of the glandular organ. In Plate V., Fig. 1, e, e, the vessels we have just spoken of represent the utero-placental vessels of an- imals which have a single placenta, and even those of the human species. Each villus of the chorion penetrates and fills a follicle (Plate IV., Fig. 1, c). It is formed of a vas- cular loop, ordinarily simple, sustained by the soft connective tissue which is furnished it by that of the chorion (f). All the villi are surrounded by an epithelium (d) which is continuous with that which covers the whole exterior of the chorion (5), the outer surface of which may be regarded as represent- ing the uterine decidua in the mare. In the same figure (a,a) we see the chorion formed of corpuscles of connective tissue, in the midst of which traverse the vessels (c) destined to form the umbilical cord. : The utricular glands of the uterus pour out their fluid between the glandular organ and the external surface of the chorion, where there is collected in abundance a whitish, albuminous liquid, resulting from a mixture of the above fluid with that which is secreted by the follicles of the glandular organ. At what period of gestation begins the formation of this new glandular organ, which represents the uterine or maternal portion of the placenta in the simplest manner and under the most simple forms by its general diffusion over the whole internal surface of the uterus? I cannot answer with precision. ON THE GLANDULAR ORGAN. 45 However, it is certain that the observation made by the ancient anatomists, that the villi of the chorion adhere to the uterus of this animal only during the last months of pregnancy, leads us to suppose, with reason, that this assertion should to-day be understood to signify that the glandular organ is formed late in the uterus. I have only been able to observe a portion of the uterus of a mare during the early periods of gestation. It had been preserved in alcohol for several years, and I discovered in it no trace of a glandular organ. Consequently, it is impossible for me to affirm any- thing probable with regard to the time and mode of formation of this new glandular organ! As a com- pensation, I was fortunate enough to be able to ex- amine the uterus of a mare killed fifteen or twenty hours after the delivery of a foetus at term. The glandular organ had remained entire in the uterus, It is certain, then, that the delivery of the animal is not accompanied by any traumatic lesion. The villi of the chorion come out from the follicles like the fingers of a glove. Yet the glandular organ had, after so short a time, undergone remarkable modi- fications. The livid red color had become yellow- ish; the volume had diminished by half; the follicles measured no more than a millimeter or a millimeter and a half in length ; their internal diameter, exam- ined by the microscope, was only a hundredth or one and a half hundredth of a millimeter at the ex- tremity, and from four to five hundredths at the base. The vascular net-work between: the follicles was no longer perceptible. 1 See Appendix. 46 ON THE GLANDULAR ORGAN. It also remains to be known how much time is nec- essary for the destruction of the glandular organ or maternal placenta, in what manner it is accomplished, and how the internal surface of the uterus is again covered with the epithelial layers which envelop it during non-gestation. I would gladly resolve these questions, and many others that relate to the period of formation and the mode of disappearance of this glandular organ or maternal portion of the placenta that I have described, in this too expensive animal. Now that I have made known the most important part of the phenomenon, it gives me pleasure to be- lieve that others, more fortunate, will meet with favor- able opportunities for observing its special features. CHAPTER IV. ON THE GLANDULAR ORGAN, OR MATERNAL PLACENTA, IN ANIMALS WITH A MULTIPLE PLACENTA, AS IN THE RUMINANTS ; OR, ON THE UTERINE COTYLEDONS IN THOSE ANIMALS. In the analysis given of the anatomical knowledge which the ancients have transmitted to us upon ani- mals with a villous or diffused placenta, we have seen that they had indicated or had glimpses of the truth, but that, in the course of centuries, it had been for- gotten, and erroneous doctrines followed. With re- gard to the cotyledons, or multiple placenta, we shall see that errors were at first committed, which ob- servers soon corrected, without, however, discovering the entire truth. It is claimed that Diocles described the uterine cotyledons, even in woman; and that Hippocrates spoke of them in his aphorisms under the name of “acetabula uteri,’* an error for which he was re- proved by Galen. Aristotle corrected the error of Diocles, affirming that “ dentata animalia cotyledones habent,” and that “ utrinque dentata non habent cotyledones.” ° 1 Quecumque mediocriter corpora habentes abortiunt, secundo aut tertio mense sine occasione manifesta: his ‘acetabula uteri’’ plena mu- coris sunt, et non possunt ex pondere foetum continere, sed disrumpun- tur. (Aphor., Sect. v. xlv.) Several commentators have affirmed that Hippocrates, after the example of Proxagoras, had given the name coty- ledons to the vascular orifices opening into the cavity of the uterus. 2 Arvistotle: Historia Animalium, cap. v. 48 THE MULTIPLE PLACENTA OF RUMINANTS. Our countryman Aldrovandi was the first to give a diagram of the cotyledons of the cow, but it is not a very good one. On the contrary, the illustrations produced by Hobokenius, especially those of Plates XIV. and XV., are very beautiful. Fabricius of Acquapendente ? and Marcus Aurelius Severin * were among the first to remark the differ- ences of volume which the uterine cotyledons un- dergo in the gravid and non-gravid uterus, particu- larly in the sheep and the cow. “Tn non gravidis,” wrote Severin, “ quidem similes grano tritici, In gravidis vero corporis raritale fora- minulenta similes hz cotyledones sunt spongiz can- dida.” But Aristotle had long before pomted out their increase during pregnancy, and after delivery “minora redduntur, demumque obliterantur.” ® | Needham had added that the caruncles of the cho- rion at the beginning of gestation are detached with difficulty from the uterine cotyledons, but that with the development of the foetus they separate easily, as If mature, “et sponte cum foetu abeunt.”® Then he continues: “ Glandule vero ipse in utero relict paulatim decrescunt.” Hobokenius also called the cotyledons of the ute- rus glands; but he described better than did the oth- ers‘ (and for the first time, I believe, under the de- nomination of ligament of the uterine glands) the 1 Aldrovandi, Ulis.: Quadrup. Bisule. Historia. Bologna, 1621. 2 Hobokeni, Nicolai: Secundina Vituline Anatomia. Utrecht, 1672. 8 De Formato Feetu Pat. 1604. * Zo6nomia Democritea. Nuremberg, 1645. 5 De Generatione Animalium, cap. v. 6 Disquisitio Anatomica de Formato Fetu, page 184. London, 1667. 7 Secundine Vituline Anatomia, page 143. Utrecht, 1672. OL ee ee THE MULTIPLE PLACENTA OF RUMINANTS. 49 pedicle of the cotyledons in the gravid uterus. He pointed out and sketched, with great exactness, the uterine vessels which go from the so-called ligament to the glands or cotyledons of the uterus. To this knowledge of the ancients Malpighi* added nothing; the moderns very little. It is generally taught that the uterine cotyledons in the ruminants are appendages of the mucous membrane; that they are perceptible in a rudimentary state, even in the uterus of the foetus; that they acquire some develop- ment after birth, become hypertrophied during ges- tation, and are persistent throughout the life of the animal. In describing the utricular glands of the uterus, I observed that Professor Spiegelberg had stated, very incorrectly, as we shall see, that the uterine cotyle- dons were nothing but expansions or dilatations of those glands. An illustrious Italian anatomist, Professor Panizza, in his last published work ? remarks, while treating of the cotyledons, that the mammillary elevations visible in the uterus of the heifer are only the rudiments of future internal cotyledons; and he speaks of the dif- ferences which they present in their development and size, according to age, the condition of gestation or 1 Observantur quoque quamplurimi in tota uteri et cornuum interiori superficie tumores inaequalis magnitudinis parum assurgentes, qui gravid- itatis tempore insigniter surgent et uteri appendices videntur seu vagin- ularum congeries unde cotyledonum nomine insigniuntur. Admittunt au- tem erumpente a chorio subintrantes radices ita, ut ex his duabus insitis partibus completa habeatur slandula, qua separatum ab utero alimentum feetui subministratur. (Opera Omnia. Epist. ad Sponivm, page 29. London, 1667.) 2 Sopra l’Utero gravido di Alcuni mammiferi, pages 11, 13. Milan, 1866. 4 50 THE MULTIPLE PLACENTA OF RUMINANTS. non-gestation, and the place which they occupy. He accepts the comparison of the ancients, likening the uterine cotyledons to the esculent egg-plant, and de- scribes the slender stem or peduncle which Hoboke- nius had pointed out under the name of ligament. Panizza states that it is flattened, formed by the uterine mucous membrane, supplied with vessels of all kinds and with nerves belonging to the cotyledon, and that the alvooli of this lattter organ, more or less large and deep, are subdivided into secondary alveoli. In advance of all others, this anatomist has touched upon the important question of the development of the cotyledons during pregnancy. And if he leaves much, perhaps, that we may desire to see explained in connection with this subject (especially after I shall have demonstrated that the portion of the maternal cotyledon is not so much the product of a hypertrophy of the preéxisting cotyledons as a veritable neofor- mation of a glandular organ at the place correspond-. ing to the mammillary tumefactions of the gravid uterus), I am yet happy to repeat his very words, be- cause they mark the date of those new and interesting researches which ought to be still further extended in order to ascertain how, after delivery, this glandular organ of new formation is destroyed or lost. Panizza writes thus :1! — “ By following in succession the early periods of gestation in the cow, we discover how the maternal or foetal cotyledons are developed. In the uterus of the cow, examined from the tenth to the thirtieth day after fecundation, we perceive the external mem- brane of the envelope of the foetus, the chorion, in 1 Op. cit., p. 13. THE MULTIPLE PLACENTA OF RUMINANTS. 5] simple contact with the internal surface of the uterus, and at those places only which correspond to the fut- ure maternal cotyledons. “The chorion becomes more opaque and full of small elevations, or soft, white points, more or less raised, according to the age of the embryo. Ob- served with the magnifying glass, these points appear more or less elongated and transparent. They are the rudiments of the cotyledons of the foetus, simply sup- ported upon the uterine parts which correspond to the rudiments of the cotyledons of the mother. As soon as it is recognized that the maternal cotyledons are only very soft expansions of the mucous membrane and of its corresponding small vessels ; as soon as it is un- derstood that the foetal cotyledons are vascular pro- jections of the vitelline membrane or chorion of the foetus, it is then clearly seen how, subsequently, with the development of these two parts, the maternal cotyledon must present an entirely alveolar surface.” The old writers have bequeathed to us but few observations upon the differences of the cotyledons in the various species of ruminants. These are very incomplete, and we have simply accepted them. As far as their form is concerned, Fabricius had said what the moderns repeat with Needham :* “ Ovis et capra, per omnia vacce similis est; praeterquam quod glan- des quee illic convex sunt, hic concave apparent et cotylae sive acetabuli nomen sensu maxime proprio ferunt.” We still agree with Harvey that the cotyledons of the hind resemble in form those of the cow, but they are much smaller and less numerous, since only five 1 Needham, op. cit., pp. 185, 188. — emme {@À (I SA E. TOTON._ EZN- TITTI. _____"_—zz==—_s 52 THE MULTIPLE PLACENTA OF RUMINANTS. have been counted in the hind, and more than eighty in the cow. The differences are not limited to the form of the uterine portion, concave in one and convex in the other. But I shall occupy myself with these diver- sities at another time. It has always been affirmed that the function of the cotyledons in the ruminants is to elaborate the nourishment of the foetus, but the ancients, as well as the moderns, have never been able to agree as to the manner in which this important process is carried on. Aristotle maintained that in the cotyledons! “ ve- luti mamma reponitur a natura foetui alimentum san- guineum.” Fabricius* admitted the direct communication of the maternal vessels with those of the foetus in the cotyledons. He saw an argument in confirmation of this opinion in certain cells containing a black pig- ment, which are often observed in some of the coty- ledons of the sheep: “ Plurimis atrisque punctis, que ab ruptura orificia venarum sunt.” William Harvey ? constituted himself the champion of the opposite doctrine: “ In cotyledones alimentum foetui reconditur non quidem sanguineum, ut Fabricius voluit, sed mucosum, ovique aloumen crassius plane referens. Unde etiam manifestum est bisulcorum foe- tus, ut alios omnes sanguine materno non ali.” Needham * was still more explicit than Harvey: 1 Op. cit., loc. cit. 2 Op. cit, p.) 39: ® Exercitationes de Generatione Animalium, page 579. Padua, 1656. Ss Opucit.,p. 20: THE MULTIPLE PLACENTA OF RUMINANTS. 53 ‘Per molem carneam filtratur succus nutritius in pla- centiferis omnibus et in glanduliferis, sive ruminan- tibus. In ruminantibus hoc peculiare obtingit, quod succus, priusquam carunculas carneas chorio accres- centes ingreditur, in glandulosa corpora extuberat, qua loculamentis quibusdam, quasi favoram alveolis ubique terebrata, surculos et digitulos a placentibus choril exporrectos recipiunt, iisdemque se mulgeri si- aunt.” Finally, not to quote too many names, I shall sim- ply notice that Haller! formulated this categorical sentence : — “In ruminantibus manifestum fit, matrem inter et foetum, non sanguinis, sed lactis esse commercium.” The ancients also gave to the cotyledons the name of uterine mamme ; and several among them, before Haller’s time, employed the term uterine milk to des- ignate the fluid which is found in the cotyledons. In speaking of the nature of this fluid, which he calls mucous albumen, Harvey says it was also known to Galen.? Vesalius declared it to be a mucous sub- stance. Malpighi* demonstrated that in the process of cooking it all the characteristics of albumen, sub- jected to heat, were plainly detected. With Need- ham, the majority were content to call it uterine milk, and to qualify it as a fluid resembling real milk. Vieussens pronounced it true milk.* Among the moderns, Duverney ° and Eschricht re- 1 Elementa Physiologie, t. viii., p. 296. Berne, 1766. 2 Op. cit., p. 574. 8 Opera Posthuma, page 162. 4 Nov. Vas. Syst., p. 41. $ (Euvres anatomiques, t. i., p. 588. 54 THE MULTIPLE PLACENTA OF RUMINAN GS. garded the uterine portion of the cotyledons as a true gland, asserting that its fluid, absorbed by the villi of the chorion, serves as nutrition for the foetus. Just here, we must not forget a comparison of Harvey’s with regard to the nutrition of the foetus in the ru- minants during the different periods of intra-uterine and extra-uterine life: — “Tdque manifestum est, quod de cotyledonibus in cervarum aliorumque bisulcorum carunculis supra diximus: nempe carneam molem in ils animalibus spongiosam esse, et, favi instar, infinitis pene acetab- ulis constare, eandemque mucoso albumine repleri, atque inde vasorum umbilicalium fines nutrimentum haurire, quod in foetum transferant: quemadmodum in jam natis anima libus venarum mesentericarum ramuli, per intestinorum tunicas diffusi, ex illis chy- lum absorbent.” ? Returning to the quality or chemical composition of the fluid found in the cotyledons, I will state that Prévost and Morin were the first to make an analysis of it, and they found it to be composed of albumen, fibrine, caseine, a gelatinous substance, a red coloring matter, osmazone, fat, and salts. Schlossberger, of Tiibingen, examined in 1855 the uterine milk of the ruminants, and he found that this fluid has the consistency of cream, and appears under the microscope to be composed of free nuclei, glob- ules of fat and epithelial cells; it possesses a slightly acid reaction, and contains albumen and salts, but no sugar. Dr. A. Gamgee ? has since shown that the reaction 1 Op. cit., p. 574. 2 Edinburgh Veterinary Review, No. 46. Edinburgh, 1864. THE MULTIPLE PLACENTA OF RUMINANTS. 55 of the liquid is alkaline, and he obtained the acid re- action only at the beginning of the process of de- composition. He has established the presence of water, albumen, alkaline albuminates, fat, and inor- ganic salts. Spiegelberg, of Freiburg, like Gamgee, found nei- ther sugar nor caseine in the fluid, and he does not think proper to give to it the name of uterine milk. As a fact which may be of importance in explain- ing the diversity of these results, we must remember that Bernard,’ in 1855, obtained sugar in the muscles and lungs of the sheep, the dog, the rabbit, and even of the human foetus, during the first periods of in- tra-uterine life. He also demonstrated its presence in the liquid of the allantois, of the amnion, and of the urinary bladder. He maintains that the sugar dis- appears from these liquids, as from the tissues of the foetus, just in proportion as the glycogenic function of the liver becomes established. Three years after, he affirmed that he had sought 1 The following are the results of the chemical analyses of Prévost and Morin and Dr. Arthur Gamgee. Prévost and Morin out of 100] Gamgee out of 1000 parts of fluid. parts of fluid from the cotyledons of | Alkaline reaction. Specific gravity, the cow. 1.038. Fahr. 60°. IA nn COST Waters a. see le RSI SEM a. 18.168 | Solid Parts’. lu © 47020.90 Albumen and fibrous sub. . 11.028} Albumen. . . . . + 104.00 Gelatinous matter. . . . 0.546| Alkaline albuminates . . 1.60 e als oh ee a OPO O Ra i ey SRL Memazone. ti ou . a 0.714 Inorganic salts «Uli . dista miracesvof salts =. + +0. 0714 2 Zeitschrift fiir rationelle Medizin von Henle und Pfeufer, b. 21. 1864. 8 Lecons de Physiologie expérimentale appliquée è la Médecine. Paris. 56 THE MULTIPLE PLACENTA OF RUMINANTS. in vain for several years for the glycogenic matter in the cotyledons of the sheep and of the cow, during the different periods of their life. He also thought he could demonstrate that if in animals with a single placenta we meet, mingled together, the vascular and glandular portions which, in his opinion, secrete the sugar, the same parts are developed separately upon distinct membranes in the ruminants; that is to say, the vascular portion upon the chorion, and the gland- ular portion upon the internal surface of the amnion. The glandular organ, or the glandular or glyco- genic cells, would be formed, according to him, by the whitish plates that are met with, during the first months of pregnancy, upon the internal surface of the amnion, and whose physiological significance was entirely unknown, even by those who had been ac- quainted with them before his time.! This subject awaits from chemistry a long series of experiments which shall interpret the phenomena in a positive manner, and clear up the difficult question of the nutrition of the foetus. I will simply state here, however, that in treating, either with nitric acid or by ebullition, the milky fluid of the cotyle- dons, which lubricated the internal uterine surface of a mare at term, I recognized the presence of albu- men; with the tincture of iodine and the addition of a drop of sulphuric acid, I obtained the characteristic reaction of starch; by using iodine alone, the disturb- | ance peculiar to dextrine was produced; finally, by a | solution of nitrate of silver there were visible traces i of the existence of chloride of sodium. In briefly i i i i | : i 1 | PI i : i | ' 1 Mémoire sur une nouvelle Fonction du Placenta. (Annal. des Sci. Nat., 4 Série, Zodlogie, t. x., p. 112. Paris, 1858.) THE MULTIPLE PLACENTA OF RUMINANTS. 57 reviewing the different opinions held concerning the structure of the cotyledons and the composition of the fluid which they secrete, I ought also to men- tion that, in recent times, Colin! has affirmed that the so-called fluid which they contain is only the product of an illusion, that is to say, the effect of post-mor- tem decomposition. Notwithstanding the assertions of Colin, these observations are so easily made and so palpable that they have been universally supported, and contradicted by no one else. The opinions which divided the ancients upon the functions of the cotyledons are then reduced to two. They are the same that still prevail to-day, modified and adapted, so to speak, to the language imposed upon us by the progress made in anatomy and physi- ology. The two chiefs of the school of antiquity are Fabricius, who admitted the direct communication of the maternal vessels with those of the foetus in the cotyledons, and Harvey, who maintained that the fluid secreted by the cotyledons was absorbed by the villi of the foetal placenta. Among the partisans of Fabricius we may at pres- ent reckon all those (and they form the greatest num- ber) who believe that the foetus is nourished in the uterus by means of an exchange of materials in the cotyledons between the maternal and the foetal ves- sels. In the number of the partisans of Harvey, we may rank all those who admit, for the ruminants at least, the absorption of the fluids separated by the cotyledons of the mother. To the latter opinion ad- here all those who think that the fluid secreted by the uterine glands serves as nutrition for the foetus, 1 Op. cit.; t. ii, p. 600. 58 THE MULTIPLE PLACENTA OF RUMINANTS. and that the cotyledons are nothing but the dilata- tions or expansions of the mucous membrane, or of a portion of the glands. This opinion has been em- braced by Spiegelberg, and was indicated by myself in speaking of the utricular glands in the ruminants. One teaching of the older anatomists, with regard to the maternal cotyledons of the ruminants, has reached us entirely unchanged, notwithstanding all the modifications introduced into the description of the fact. It is that in the uterus of the ruminants, even at the foetal period, we find rudiments of coty- ledons, which in extra-uterine life increase in size, are. greatly developed during pregnancy, and diminish after delivery, though always remaining in the uterus. Nor has this teaching been essentially modified by the views of those modern writers who, instead of attributing the development of the cotyledons, during gestation, to an enlargement of the mucous mem- brane, ascribed it to a dilatation of a portion of the utricular glands. No one suspected that this develop- ment depended upon the formation of a new gland- ular organ, which differs from that I have described as being observed in the uterus of the mare, in one feature only, namely, that in the latter animal the ne- oplasm takes place over the entire uterine surface un- der the simplest forms, and not over certain circum- scribed areas, with a more complicated structure, as in the ruminants. Before making this important observation upon the uterus of the mare, which opened the path to the in- vestigations of which I treat, I lost several months in the comparison of the structure of the maternal cotyledons of the gravid and non-gravid uterus of THE MULTIPLE PLACENTA OF RUMINANTS. 59 ‘cows. My patient fellow-laborer in these fruitless — researches was the excellent young doctor Severi. But we could never detect a single indication, how- ever vague, of the probability, to say nothing of the certainty, of the doctrine supported by Spiegelberg.! In speaking of the uterine glands, I stated that, by the aid of transverse sections of the cotyledons of the non-gravid uterus, I had assured myself that, besides the utricular glands, very numerous agglomerations of slender follicles were to be seen in them (Plate V., Fig. 2). Iwas very far from suspecting the neofor- mation of a special glandular organ in the uterus of all mammals, whatever might be the form of the pla- centa; and the observation did not allow me to admit either the dilatation or the expansion of the utricular glands in the formation of the cotyledons of the gravid uterus. I therefore sought for the solu- tion of the problem in these slender follicles, which I supposed must become hypertrophied during ges- tation, and remain atrophied during the period of vacuity. When I speak of the formation of the placenta in those animals in which that organ is single, and when I describe what I have seen take place in the small follicles of the uterine mucous membrane of rabbits, it will appear that it would have been an allowable supposition that the same phenomenon might be re- peated, with certain modifications, upon the mucous membrane of the cotyledons, in order to form their glandular portion. I prefer, however, to remain in doubt until facts shall have settled the matter con- clusively ; all the more, that certain observations 1 See the first part of this Memoir upon the Uterine Glands. 60 THE MULTIPLE PLACENTA OF RUMINANTS. seem to contradict this method of formation for the glandular or maternal part of the placenta in the ru- minants. In making vertical sections of the cotyledons and the walls of a gravid uterus, we observe three dis- tinct parts: first, the walls of the uterus; second, a fold of the mucous membrane, narrowed at its base, broadening towards the summit, whence arise pyram- idal dissepiments of connective substance, which go to make up the third part, or superior portion of the cotyledons. The fold of mucous membrane consti- tutes that which is at present called the pedicle of the cotyledon, or the ligament of Hobokenius, through. which the vessels are carried to the third and last part, that is to say, to the glandular portion of the cotyle- don of ancient and modern anatomists. The pedicle represents the old or permanent part of the uterine cotyledon of the cow. Ido not speak of the differences which are observed, in regard to this, in the sheep. The third or superior portion, more remarkable still, represents the glandular organ of new formation, which remains in the uterus after de- livery, and which then disappears, as we have seen occur with the uterine glandular organ of the mare. It remains to be demonstrated whether, in both cases, this complete disappearance is the effect of a simple i progressive atrophy; or whether, in the cow, the glandular portion of the cotyledons is destroyed by fatty degeneration, as the uterine mucous membrane is, at the place where the single placenta of the car- nivora has been formed. Yet, from the facts de- scribed above, it follows evidently and clearly that, as a result of pregnancy, the convex surface of the "J È a 2 THE MULTIPLE PLACENTA OF RUMINANTS. 61 old cotyledon has lost the form and anatomical struct. ure which it possessed. It is no longer smooth and slightly convex; for from its whole surface have arisen long and slender pyramids, which, in the sec- tions, appear almost digitate, and consist, in a great measure, of connective tissue of new formation (Plate VI., d, d), and of vessels which are a prolongation of the uterine vessels (Plate VI., f,7). Then, as a con- sequence of pregnancy, there takes place in the fixed and permanent portion of the cotyledons a neoforma- tion of connective tissue, which, we shall see, is the stroma of the new glandular organ. In short, there is produced, in a more complete and complex man- ner, what we have seen take place normally in ‘the uterine mucous membrane of certain mammals, in which, the uterus being non-gravid, this membrane rises in large, festoon-like folds. The examination of the pedicle by transverse or longitudinal sections allows us to see the vessels, much increased in size, arranged in the form of a close net-work upon the appendages of connective tissue, which separate the new or glandular part of the cotyledon into different compartments. The utricular glands and the follicles have also acquired a greater diameter; only they are perceived with more difficulty in proximity with the base of the glandular organ, and if we succeed in discovering them we find that they have lost the round form in their transverse diameter, and that they have acquired an elliptical form, or are even subdivided, and we are no longer able to distinguish the internal epithelial element, on account of their transparency. In the glandular follicles I have sometimes been 62 THE MULTIPLE PLACENTA OF RUMINANTS. able to see more easily the internal epithelium changed into very diaphanous granular globules (Plate VI, Fig. 1, m, m). As to the structure of the new glandular organ, anatomists, ancient as well as modern, contented themselves with asserting that it presented exter- nally several openings or points, which led Malpighi to compare it to the mushroom, called with us spon- zuola. Panizza remarked, with somewhat more pre- cision, that these external cavities are subdivided on the interior into several secondary alveoli. It is difficult, at the first glance, to form an exact idea of the internal anatomical arrangement of the glandular organ. I have tried to show it in diagram, Plate L, Fig. 2, and I hope that a precise idea may be had of the structure of this organ, by comparing it with Plate VI., Fig. 1, which represents in natural size, and also when magnified two hundred and fifty diam- eters, a portion of the glandular organ of a gravid cow, at the third month of gestation. I have stated above that from the surface of the uterine cotyledon, in vertical sections, columns or pyramids of connective tissue are seen to rise (Plate VL, Fig. 1, d, d). They form the walls of correspond- ing calices, somewhat irregular, joined and crowded close together, which open outwardly through sluices or clefts of various form and extent, to allow a passage for the villi of the chorion. Over the internal sur- face of these calices are distributed, in very great numbers, lamelle of connective tissue, which form tubes opening into the cavity. These tubes, covered over their inner surface and at their common orifice with pavement epithelium, constitute utricular glands, THE MULTIPLE PLACENTA OF RUMINANTS. 63 which are no longer vertical to the mucous mem- brane, as in the mare, but are placed along its trans- verse axis. Nor are they simple, as in the first case, but are superimposed upon each other. The form of the calices, the base being narrow and the outward opening quite large, renders it impossible to make vertical sections continuously upon any num- ber of these utricular glands, as they are represented in the diagram. In fact, they are cut in every direc- monn( Plate Vi. Wig. 1, 6,0, 6, 00)... At the. dirsi glance one sees only a quantity of openings, without any order; then, on fixing the attention upon the section (0, è, 6), at certain places, glandular follicles be- come visible, and, in their cavities, the cut chorial villi (a, a, c,c). There then remain for investigation the method of formation of the glandular organ, or of the portion of the cotyledon which is developed during pregnancy, and the retrograde metamorphoses by which the same organ disappears after delivery. I have been wholly without the materials necessary for making these observations. Panizza, as I have said, had pointed out how the chorial villi, or cotyledons of the foetus, were devel- oped at the places corresponding to the uterine cot- yledons, without stating anything precise upon the observation. Now I ought to note one fact that I have noticed in regard to the foetal cotyledons. I do not in the least doubt the assertion of Panizza ; however, the examination of the chorion of cows in the third month of gestation, or a little earlier, de- prived of the cellular envelope of its external surface which constitutes the decidua, and then subjected to the ordinary methods of imbibition, allowed me easily 64 THE MULTIPLE PLACENTA OF RUMINANTS. to establish the fact that the formative process of the cotyledons of the foetus obtains largely over the whole external surface of the chorion, and that they are de- veloped, in remarkable proportions, at those places only which correspond to the uterine cotyledons. Where these do not exist, the formative process of the foetal cotyledons aborts, so to speak, and, with the aid of the microscope, is seen only in the form of cer- tain small elevations, with broad, serpentine lines, formed of cells of fibrous tissues, which are supported upon a net-work of large corpuscles of connected tis- sue, with short and broad prolongations. On their walls we observe certain nuclei. The whole forms an extended and elegant mesh, which has lost the character of the corpuscles of the connective tissue without having acquired that of a real vascular net- work. The poverty of resources at my disposal, and the great difficulties to be met with in this kind of re- search upon such expensive animals, have forced me entirely to neglect some other phenomena which I should very much have liked to make clear. If, in the future, favorable opportunities are still to be de- nied me, I hope they will be offered to others who will take advantage of them, in order to fill up the blanks which, in spite of myself, I am forced to leave in this work. : CHAPTER V. ON THE GLANDULAR ORGAN, OR MATERNAL PORTION OF THE PLACENTA, IN ANIMALS WITH A SINGLE PLACENTA. RraLDpo CoLomso designated that part of the ovum which is brought into contact with the uterus of the mother, in the human species, by the name of pla- centa.. Accepted by the moderns, this name has been extended to all mammals, without regard to the form of the organ. However, in respect to differ- ence of form, it is distinguished as disseminated or diffused, multiple, and single placenta. Having already spoken of multiple and diffused or villous placenta, I am now to treat of single placenta, the structure and function of which have given rise to diversities of opinion that still prevail. I shall certainly not consider all of the many and various conceptions upon this subject, but shall simply confine myself to those that are in direct relation with the new observations I shall present, because I believe that even the imperfect observations and the errors 1 Realdi Columbi de Re Anatomica, lib. xii., p. 248. Venice, 1559. Vesalius, before him, had called it orbicular flesh, and he was the first to give a special name to this part of the fatal envelopes. At the present time it is generally believed that the term placenta is due to Fal- lopius, because in his Observationes Anatomice he wrote, ‘* Carnem que placenta a me dicitur;’’? but Noortwyck has justly remarked in his book (Uter. Human. Fab. et Heist., page 116, Leyden, 1743) that the observations of Fallopius were not published until 1561, and consequently two years after the publication of the Anatomy of Realdo Colombo. Ò 66 SINGLE PLACENTA IN ANIMALS. of our predecessors, in a determined order of ideas, are of great service in forming an exact judgment upon new researches. In these historical studies in connection with the single placenta, it seems to me that the most impor- tant point to be explained and placed in the clearest light is the question whether the placenta belongs entirely to the foetus, or whether it is distinguishable into two parts, one belonging to the mother and the other to the foetus. Harvey! had said concisely: “ Placentam partem esse foetus, non matris.’ This categorical formula, adopted by several authors, ought not to have been accepted, it would seem, after Hunter ? had so clearly demonstrated the existence of the vessels which go from the uterus to the placenta, named by him utero- placental. The existence of these vessels was after- wards wrongly denied, and a considerable number of modern observers® have believed only in a simple superposition of the two organs; and instead of con- sidering the decidua serotina as a means of union, they have attributed to it the characteristics of a thin and delicate inorganic tissue, destined to keep the two organs separate. The idea of the placenta being separable into two parts, the maternal and the foetal, is ancient, and, for certain animals at least, really belongs to Fabricius, 1 Op. cit., p. 290. 2 The Anatomy of the Human Gravid Uterus. London, 1794. 8 Lee, Philos. Transact., 1832, page 57. Velpeau, Embry. ou Ovolog. humaine, Brussels, 1834, pages 63, 70. Radford, On the Structure of the Human Placenta, Manchester, 1832. Seiler, Die Gebarmutter und das Ei des Menschen, 1832, page 31. Ramsbotham, Millard, and Noble, Lon- don, Med. Gaz., 1834 and 1835. SINGLE PLACENTA IN ANIMALS. 67 who declared that in guinea-pigs the placenta is double! However, the distinction of the two parts of the placenta is generally accorded to Wharton :* — “ Etenim ipsa placenta duplex est. Altera ejus me- dietas pertinet ad uterum, altera ad chorion. Atque hee medietates inter se apte committuntur, seu potius inoculantur. Constat enim ex ineequali superficie : nimirum alveolis et protuberantiis sibi mutuo apte respondentibus : ita ut alveolis unius medietatis pro- tuberantiam alterius in se excipiat et undique amplec- tantur.” The doctrine attributed to Wharton was soon com- bated, and Needham,’ after reviewing the passage I have quoted, adds : — “ Hee sententia ad literam vera est, si de rumi- nantibus sermo sit quibus omnibus uteri intima mem- brana statim a conceptu in tales glandulas exsurgit, et foeture preludat. At vero placentule a parte matris respondentes in solis glanduliferis [that is to say, the ruminants] occurrunt.” Notwithstanding this, Needham himself, who main- tained that the placenta is simple, ed soli chorio propria, in the carnivora as well as in woman, on comparing the gravid uterus in different animals, made with re- spect to the rodents an observation analogous to that which Fabricius had made upon the guinea-pig, and writes : — “In cuniculo placentz bine sunt, neutra tamen uteri dicenda est, utpote qua chorion in partu comi- 1 « At in porculis indicis privatim, duplex carnea moles, altera alteri superposita observatur.’’ (Op. cit., p. 39.) 2 Adenographia sive Glandularum Totius Corporis Descriptio, page 218. Amsterdam, 1659. 8 Op. cit., p. 26. enza OG 68 SINGLE PLACENTA IN ANIMALS. tantur cum eadem exeunt. Adeo ut haec animalia inter placentifera et glandulifera media videantur ; ” and a little further, still speaking of the placenta of rabbits :* “ Singulis nempe foetibus, singulas placentas impertit hoc animal, que tamen utero mediante glan- duloso corpore agglutinantur.” | This same fact was recorded by Graaf? though op- posed by him to the doctrine of Wharton :— “In cuniculis vero et leporibus et quibusdam aliis animalibus ea parte, quà chorio annectitur, rubet ; al tera vero, qua cum utero copulatur, albicat, et utra- que cum foetu simul excluditur, sic ut illa non magis quam altera ad uterum pertinere videatur.” Our own Malpighi, without describing them, di- vined more clearly than any other the two parts of the placenta, and assigned to each a different func- tion. According to him, the placenta “est glandula conglobata sui generis, in qua portio uteri, propria carne donata, receptum ab uterinis arteriis succum percolat, qui separatus in sinuosis cavitatibus recol- ligitur, donec sensim fistulosas alterius glandule parti radiculas subeat, et venarum surculis excipiatur.” ° The special observations and the doctrines of Fa- bricius, Needham, Graaf, and Malpighi were soon for- gotten, and opposite statements were made. Haller, for example, after having said that “ cu- niculi placenta ad humanum accedit,” * adds at page 243 : — ‘In cuniculo, placenta humane similis sanguine plenissima tuberculis suis ad similia tubercula uteri 1 Op: (cits. pp: 20, 180. 2 Opera Omnia, page 207. Leyden, 1678. 8 Opera Omnia, page 25. London. 4 Element. Physiol., t. viii., p. 224. Berne, 1766. SINGLE PLACENTA IN ANIMALS. 69 b) adherescit ;” and as to the glandular structure, he af- firmed that there was no trace of glands in the pla- centa.! Sixty years afterwards, Velpeau ? declared that no one believed in the presence of glandular parts in the organ. | Many years did not pass, however, before the idea that Malpighi had formed of the placenta was revived by the observations of von Baer? and Sharpey and all those who believed that in some animals at least the utricular glands of the uterus entered into the structure of the placenta. At the same time they disguised, as it were, the fundamental idea, by sup- posing that the extreme ramifications of the foetal vessels of the villi of the chorion were brought into contact with the vascular net-work which envelops the uterine glands, and that by the extreme attenua- tion of their walls the exchange of materials between the blood of the mother and that of the foetus was always carried on in the same manner. 1 «Ut nulle veri nominis glandule in placenta sint.” (Op. cit., p. 234.) 2 Op. cit. 8 The following are the thirty-first and the thirty-fourth of the gen- eral conclusions of von Baer’s work, Zusiitze zur Lehre vom Baue, und Verrichtungen der Geschlechtsorgane. Leipzig, 1846. ‘“ It cannot yet be admitted that the villi of the chorion in woman penetrate into the uterine glands, as in dogs, since woman alone possess- ing a membrana decidua which distinguishes her from other mammals, there may exist a difference of formation between the human placenta and that of the dog. “ Tf, in the end, it should be demonstrated that the villi of the chorion in woman as well as in the dog penetrate into the uterine glands and distend them, it would follow that the ramifications and terminal fila- ments of the villi of the chorion take on a delicate covering which pene- trates with them, and which they receive from the wall of the uterine glands. Even in that case we could hold the accepted doctrine upon the structure of the placenta and upon the mode of formation of its parts.” 70 SINGLE PLACENTA IN ANIMALS. It must be confessed, however, that the observa- tions of Sharpey and Weber gave rise to certain doubts in the mind of the illustrious Bischoff, whose exact words it is advisable to reproduce: “If it be true,” he wrote, “that the placenta of the dog, as Sharpey affirms, owes its origin to the penetration of the villi of the chorion into the glandular canals of the uterus, which are surrounded by a capillary net- work of uterine vessels, and that these canals and these villi, by continually augmenting in size and ramifying, become entangled with each other, as I have been able to prove by my observations upon the dog; if it be true also, as Weber and Sharpey af- firm, that the human decidua is formed only in great measure by the highly developed uterine glands, and that its sieve-like appearance depends upon the open- ings of these glands, it becomes very probable that in the human species likewise the placenta owes its genesis to the fact that the chorial villi, constituting the umbilical vessels, penetrate into the glandular canals upon one point of the internal face of the uterus, and that both, continuing their development, finally constitute its organization. It is evident, then, that the meeting of the two bloods in the placenta does not consist in a direct interchange of materials between them, but that the vessels and the uterine glands elaborate a secretion, which is seized upon by the villi and the umbilical vessels that have penetrated into the glands.” The doubt expressed by Bischoff was welcomed by certain eminent physiologists, even in our own day. 1 Entwickelungsgeschichte der Sdugethiere und des Menschen. Leip- zig, 1842. SINGLE PLACENTA IN ANIMALS. af No new fact has been brought forward, however, either to confirm or to contradict it. The opinion which has met with the greatest acceptation is that the uterine portion of the placenta is produced by the vessels of the mother which are conducted to it. Upon this point there was almost universal agree- ment. The divergences of opinion had reference to the manner in which the maternal vessels are brought into contact with those of the foetus. I have elsewhere said that I reckon among the defenders of the ancient doctrine, which maintained the direct communication of the blood between the mother and the foetus, those of the moderns who, while rejecting the basis of the doctrine, claim that the exchange of materials for the nutrition of the foetus is carried on by the process of endosmose and exosmose through the walls of the maternal and foetal vessels. The numerous defenders of this doctrine ought to be divided into two classes. In the first, I would rank all those who consider the placenta as nothing but a vascular net-work ; the second would comprise those who, while accepting the principle, admit fur- ther that the vascular net-work of the maternal pla- centa is sustained by the folds of the mucous mem- brane of the uterus or by the decidua serotina in the human species. Galen’ was the leader of the first class: “ Venas et arterias choril in uteri venas et arterias insertas esse principium secundinarum,” although he had said in another place ° that the placenta is a glandular flesh which is formed around the vessels of the uterus. 1 De Formato Feetu. 2 Aphorismi, 45. 72 SINGLE PLACENTA IN ANIMALS. Fabricius, among the ancients, maintained ener- getically the theory of direct vascular communication between the mother and the foetus. Though com- bated by other observers, the opinion of Fabricius has always found, up to the present day, both friends! and opponents.” I have already quoted a few of them. I will add that the illustrious Italian anato- mist, Panizza, summing up in his last work? the dis- cussions that took place on the subject at the scien- tific congresses of Naples, Florence, and Padua, shows that several able men have been led into error by certain processes (injections), which seemed to prove direct vascular communication between the maternal and the foetal blood; and he cencludes that this direct vascular communication does not exist, but that the sanguineous system of the mother and that of the foetus form a special circulatory apparatus, maintain- ing with each other an intimate and complicated vascular contact, even in the smallest loops of the arteries and veins. Long before Panizza, Bischoff had acknowledged that there remained one problem to be solved: to de- termine how the maternal and the foetal vascular sys- 1 Cowper: The Anatomy of the Human Body, 1698. Noortwyck: Uteri Humani Gravidi Anatomia et Historia, 1748. Vieussens: Disser- tatio de Structura et Usu Uteri et Placente Muliebris. Haller: Ele- menta Physiologie, t. viii., p. 255. Senac: Traité de la Structure du Ceur. (Paris, 1783.) Florens: Cours sur la Génération, page 138. (Paris, 1836.) 2 Monro: Edinburgh Medical Essays, vol. ii., p. 68, 1749. William Hunter: The Anatom. Descript. of the Human Gravid Uterus. (London, 1794.) Wrisberg: Comment. Medic., 1800. Bischoff: Entwickelungs- geschichte der Siugethiere und des Menschen. (Leipzig, 1842.) Jac- quemier: Archiv. génér., page 165, 1738. 8 Sopra |’ Utero gravido di Alcuni mammiferi, pages 14 and 15. Milan, 1866. SINGLE PLACENTA IN ANIMALS. lo tems are disposed in the placenta, and what are the parts which serve to support these systems. It is generally believed that they tend more and more, from the beginning of their existence, to coalesce into one uniform organ, the placenta, in which the two parts, the maternal and the foetal, are not distin- guishable except at the first period of development.' But as to the constitution, even primordial, of the maternal portion of the placenta, the only thing the best authors say about it is that “the vessels of the chorion are brought into relation with a correspond- ing and somewhat vascular portion of the uterine mucous membrane, of a reticulated and cellular ap- pearance, and that this portion constitutes the uterine part of the placenta.” ° Hirtl®? makes the same observation, and writes that “upon one point of the uterine mucous membrane there is developed a colossal net-work of venous ves- sels, forming the so-called maternal placenta, which receives into itself the prolongations or projections of the embryonic placenta.” I pass over in silence the moderns who repeat the doctrine of the ancient anatomists, according to which the point of the uterus where the ovum is arrested becomes almost fungous (caruneule uterimee), and the fungosities, constituting the maternal portion of the 1 Miller, Professor at the Veterinary School of Vienna, published at Berlin (Miiller’s Arch.) a memoir upon the structure of the placenta in the Dasyprocta Aguti. In this animal the two portions of the placenta remain distinct, though in vascular communication throughout the time of gestation. 2 Bischoff, Op. cit., Dell’ Allantoide. 8 Manuale d’Anatomia topografica, t. ii., p. 112. Italian translation. Milan, 1858. 74 SINGLE PLACENTA IN ANIMALS. placenta, mingle with those of the chorion, or foetal placenta, to form one single placenta. Madame Boi- vin and Velpeau,’ who did not admit the double pla- cental structure, said with reason: “If the placenta be thus formed, it remains to be known at what pe- riod and in what manner the fungosities or caruncles of the uterus are separated, the placenta being sep- arated from the uterus by the decidua serotina.” The theory that each of the two placental parts is formed by very thin folds or sheets irregularly doubled over each other belongs to Eschricht.2 According to him, those folds which constitute the foetal placenta project vertically from the chorion. As to the mater- nal placenta, he declared that he had seen, especially in the cat, that the uterine portion forms a vascular membrane, which, while originating in the mucous membrane of the uterus, differs from it completely ; it is transformed into very small folds, among which are set the villi of the chorion, which have also, he claims, a lamellated appearance. Among the rodents, also, the placenta consists of a uniform crossing of the lamelle of the chorion and of the vascular membrane of the uterus. Bischoff favored these opinions, and added that in rabbits, dur- ing the first period of gestation, when the placenta begins to develop, he had distinctly seen the folds of mucous membrane covered with an elegant vascular net-work. But in that animal he did not find uter- ine utricular glands inclosing the villi of the chorion, as is the case in the dog, in which latter animal he 1 Embryologie et Ovologie humaine, page 46. Brussels, 1834. 2 De Organis que Respirationi et Nutritioni Fetus Mammalium inser- viunt, pages 13 and 20. Copenhagen, 1837. SINGLE PLACENTA IN ANIMALS. 1D had been able to verify the observations of Sharpey and von Baer. Miiller* accepted these observations as demon- strated. He even set them up as a general princi ple, advancing the idea that the placenta presents two capital modifications: first, the development of branching villi of the chorion penetrating into the uterus; second, the formation in the uterus and the chorion of highly vascular folds which fit into each other. But shortly after, the same Muller, in speak- ing of the human placenta, forgets his general teach- ing, and declares that that organ is composed of two elements or two portions, the foetal and the uterine, which penetrate reciprocally into each other. The foetal placenta consists of vascular trunks rich in branching villi; the uterine is formed of the sub- stance of the decidua, which insinuates itself between the villi, and envelops them completely as far as the surface of the chorion. He adds that, according to Weber, the relation of these two parts is very differ- ent in the human being from what it is in the other mammalia. In the latter, the vascular villi of the foetus are prolonged like roots into the equally vas- cular sheaths of the uterine placenta, so that the two systems of capillary vessels touch each other, and there is thus an exchange of materials between them. In the human species, on the contrary, the villi of the foetal placenta penetrate deeply into the large san- guineous vessels proceeding from the maternal veins, so that the vascular loops of the foetus are bathed in the blood of the mother. 1 Manuel de Physiologie, t. ii., p. 730. Paris, 1851. AOP city Ps (94 76 SINGLE PLACENTA IN ANIMALS. On the other hand, Eschricht believed that in woman, as well as in the other mammals, it is only the capillary net-work of the decidua which enters into contact with the vascular loops of the foetal villi. In this case, the structure of the uterine placenta would be in every way the same as that of the foetal placenta. In the midst of so many uncertainties, it gives me pleasure to call your attention to an observation of Cuvier, amplified by Miller, namely, that in certain fishes (the squalde), such as the carcharias, the pri- onodons, and the scoliodons, the foetus is united to the uterus by means of a placenta; and that, moreover, in those animals the uterine placenta is formed of very elevated folds of internal uterine membrane, which correspond exactly to the folds of the foetal placenta, and they are as intimately blended as in the uterine and the foetal placenta of the mammalia. It has not been my privilege to confirm by my own researches this observation, which I do not hesitate to consider of very great importance for the class of subjects which I am laying before you. I pointed out at the beginning the change of the folds of the uterine mucous membrane into a glandular organ, when the placenta is single. The placenta of the squalide, according to Cuvier, would represent in the simplest and most elementary manner the placenta of the mammalia which have that organ single. Now, the perception of these progressive transitions of nature, as we may call them, always serves as a con- firmative argument, and as an elucidation for the most complicated observations. It establishes the great 1 Oprcib.yp ps a2o: SINGLE PLACENTA IN ANIMALS. FATE secret of the high utility and of the ever new and ever fresh interest of studies in comparative anat- omy. It is therefore with the greatest regret that I have been obliged to leave this blank unfilled.’ I shall now speak briefly of the principal opinions that have been admitted as to the functions of the placenta, further limiting my researches upon the subject to the main points which have or may have connection with the new observations which I shall present, putting aside altogether the functions, more or less probable, which observers have from time to time attributed to it, by induction. The opinion of Fabricius, that the placenta served only to hold and preserve the vessels,” found no par- tisans. Haller wrote:* “Nemo, ut puto, negat, ab utero in foetum, per placentam, succum aliquem ali- bilem percolari. De natura succi quesitum est, quem uterus in placentam mittat.” Among the old writers, several conceived the idea that, even in the case where it is single, the placenta elaborates a kind of fluid, analogous to milk, to serve as nutrition for the foetus. Although such a function was imagined without the support of any actual observation, yet the opinion of the ancients found advocates among certain of the moderns, who sup- posed the existence of such phenomena as would give it an appearance of truth. It is strange, how- ever, that other real phenomena, having a certain value as support for the ancient doctrine, although 1 See Appendix. 2 « Preecipuum utilitatis seopum in hac efformanda fuisse vasorum cus- todiam atque propugnaculum.’’ (Op. cit., p. 87.) 8 Elementa Physiolog., t. viii., p. 238. Berne, 1766. 78 SINGLE PLACENTA IN ANIMALS. observed by able anatomists and physiologists, have not been sufficient to bring it forward again. I believe that Wharton! was the first to affirm that the fluid elaborated by the placenta was in every re- spect like the milk of the mammalia. Harvey had merely contented himself with comparing, from a functional point of view, the placenta to the breast: “Jecur, inquam, est organum nutritium corporis, in quo est: mamma infantis; placenta embryonis.”? Graaf was much more explicit: “ Existimamus ita- que,’ he wrote, “non sanguinem sed lacteum quem- dam humorem esse, qui ab utero ad foetum defertur.” ® It would be tedious to name all those who accepted the doctrine of Graaf, modifying it somewhat,* or de- parting only slightly from it, and supposing the ex- istence of special lacteal vessels destined to convey through the placenta the maternal chyle to the foetus. The illustrious Haller, after having mentioned their opinions, does not hesitate to affirm: “ Sed li quidem viri® fabricam ruminantium animalium ad hominem traduxerunt.” Lauth ® restored scientifically, so to speak, an opin- ion of Hippocrates by describing numerous lymphatic 1 « Succus enim quem conficit in embryonis usum, lacteus plane est et lacti in mammilis genito simillimus.’? (Adenographia sive Glandularum Totius Corporis Descriptio. Amsterdam, 1659.) 2 Exercitatio de Generatione Animalium, page 574. Padua, 1866. 8 Opera Omnia, page 208. Leyden, 1678. 4 « Aliquid forte lacti simile ad ovum ex utero venire.” (Van-Swieten.) 5 Verhejen, Vieussens, Falconet, Jenty, Deidier, Fizes, and others. 6 «In muliere et pecoribus ejusmodi venulas et consimiles alias ad mammas et uteros ferri ; quodque iis vehitur pingue, cum ad uterum per- venit lactis formam habere, ita ut puer, quod in sanguine dulcissimum est, ad sese attrahat simulque aliquantula lactis portionis fruatur.’’ (De Natura Pueri, page 241. Geneva, 1657.) ¥ é ut SINGLE PLACENTA IN ANIMALS. 79 filaments, of a special kind, which pass from the ute- rus to the placenta. Before Lauth, Everard! had de- scribed, in rabbits, chyliferous vessels going directly to the uterus. The observation of Everard received no more confirmation than that of Lauth. Finally, I should notice that Arantius had claimed that the placenta not only prepared, but purified, the blood for the foetus; and since, in his time, this function was considered as belonging, for adults, to the liver, he named the placenta the uterine liver. Bartholin upheld this opinion. It is also this same opinion that Bernard? has restored to scientific repute in his re- cent observations, tending to demonstrate that there really does exist in the foetus a placental hepatic or- gan, which produces glycogenic matter; an organ. which disappears just in the same proportion as the liver of the foetus performs the same function. Prepossessed with such a conception, Bernard did not like to abandon it, even when he encountered gly- cogenic glandular cells in the placenta of certain an- mals. It was sufficient for him to have found sugar in the placental cells, to regard them as representing in themselves alone the glandular organ. I consider it useful, therefore, to give you at this point a sum- mary of the observations of this illustrious physiolo- gist; for although incomplete, they serve to confirm those I shall myself offer you. He wrote that® in - the placenta of rabbits and guinea-pigs a whitish sub- stance is met with, formed by agglomerated epithelial 1 Novus et Genuinus Hominis Brutique Exortus, pages 132 and 282. Middelburg, 1661. 2 Mémoire sur une nouvelle Fonction du Placenta. Paris, dans les An- nales des Sciences naturelles. Série quatrième, t. x. Zodlogie. Os OT Tene yal ys 80 SINGLE PLACENTA IN ANIMALS. or glandular cells. He found these cells, like those of the liver of the adult animal, full of glycogenic mat- ter, and they appeared to him to be placed in great- est numbers chiefly between the maternal portion and the foetal portion of the placenta. It seemed to him also that these cells became atrophied in proportion as the foetus approached the time of birth. Finally, he recognized that the placenta of rabbits and guinea- pigs is formed of two parts, which have distinct fune- tions, — one part vascular and permanent until birth, the other part glandular, which prepares the glycoge- nie matter and which has a more limited duration. In connection with these recent observations, we cannot forget the more ancient ones of Fabricius, Wharton, and Needham upon the placenta of the same animals. But, to return to Bernard and his researches, he proposed to himself to solve the ques- tion whether the function of the liver in the adult is likewise fulfilled by the hepatic placental organ, or whether, in the liver alone, the elements which elab- orate the amylaceous matter and those which form the bile are distinct from each other. ‘ I shall not enter upon this question, on account of the discussions which would arise, especially after the careful observations upon glycogenesis of my illustri- ous friend, Professor Seniff’’ I shall note, however, one physiological and anatomical fact to be observed in the placenta of dogs. This fact, indicated by Mar- cus Aurelius Severin? and by Needham, and which I have myself confirmed, was neither observed nor in- quired into by those of the ancients who, from the 1 Nouvelles Recherches sur la Glycogénie animale. Paris, 1866. 2 Zodtomia Democritea, page 307. Nuremberg, 1645. SINGLE PLACENTA IN ANIMALS. 81 point of view of function, compared the placenta to the liver. It was not even known by Bernard, who could have utilized it in his researches. In order to recall it, I shall quote the very words of Needham,’ who, in describing the placenta of the dog, said, “ In media parte tota rubet. EÉxtremis vero lateribus utrin- que viridis est: hujus rei ratio mihi nondum constat.” Neither have I been able to discover it. I will only add that the green matter in question is found more copiously elaborated by the epithelial cells covering the large folds of mucous membrane which rise around the placental edges, and the internal half of which has been transformed into a glandular organ in the placenta. We often find this green matter, which has the appearance of oil, accumulated between the folds or festoons of the mucous membrane. It dis- solves completely in alcohol, imparting freely to the alcohol its own color. I believe that it would be worth the attention of chemists to determine the nat- ure of it. Those very authors who had seen the villi of the chorion penetrating into the utricular glands of the uterus did not imagine that the secretion of these glands is concerned in the nutrition of the foetus. They either simply pointed out the fact, like Bisch- off, in a doubtful manner, or else they thought that it might take place in certain animals only, as did Mul- ler? who made an excellent review of the observa- tions of the most able modern anatomists and physi- ologists. It would result from these observations that the 1 Op. cit., p. 27. 2 Manuel de Physiologie, page 736. Paris, 1867. 6 82 SINGLE PLACENTA IN ANIMALS. cellular arrangement which envelops the villi of the chorion during the period in which they are deprived of vessels is destined to take up the substances which the villi afterwards transmit to the embryonic cells; and that when the vessels have penetrated into these villi they take possession of the nutritive substance, in order to carry it to the foetus, receiving it either from the maternal blood which in woman surrounds the villi, or from the white liquid of the uterine glands of animals. This meeting between the maternal fluids and the vessels of the villi in the foetus also takes the place of respiration, and is its equivalent. Notwith- standing this, some modern physiologists of great rep- utation * acknowledge that they do not yet understand clearly how the exchange of materials is carried on between the mother and the foetus in the mammalia. In the mammalia we must distinguish two different periods of foetal nutrition. At first, the ovum, while the placenta is not formed, finds the elements of its nutrition in the fluids which are poured out in abun- dance into the uterine cavity through the utricular glands; just as the young chicken finds in the white and in the yolk of the egg the albuminoid substances, the fat, the mineral matters, and the water necessary for its nutrition and development. But these ele- ments not being sufficient for the complete devel- opment of the embryo, there is established always, though at different periods, according to the differ- ent classes of animals, an intimate bond of union be- tween the mother and the foetus. And though it has always been admitted by all authors that this 1 Vierordt: Elementi della Fisiologia dell?Uomo, page 837. Milan, 1857. SINGLE PLACENTA IN ANIMALS. 83 relation is established by means of the placenta, we have just seen how many theories have been enter- tained as to the mode in which this organ performs its functions. Although the opinions I have indicated have refer- ence to a limited order of ideas, yet they leave a great uncertainty in the mind. This uncertainty would be greatly augmented if I were to quote the interpretations which were imagined without the aid of actual observation. Now, I have had the good fortune to demonstrate, in a positive manner, the neoformation of a glandu- lar organ over the whole internal surface of the ute- rus of an animal with a diffused or villous placenta, forming beyond all doubt its maternal portion. This fact, entirely new to anatomical science, aided me better to understand the same fact in cases where the placenta is multiple, as in the ruminants. These observations will also aid me now to demonstrate it in animals with a single placenta, in order to fix the idea firmly in our minds that always and under all circumstances, as I said at the outset, the relation between the mother and the foetus is established by means of a glandular organ of new formation, and that this organ constitutes a really special or mater- nal part of the placenta, very different in structure and function from the other or foetal part. This fact once proved and this new truth assured to anatomical science, the physiological study of the foetal nutrition and of the placental functions will find in clear and precise anatomical knowledge the basis which it lacked. It is not useless, therefore, to recall at this point the idea I have before advanced 84 SINGLE PLACENTA IN ANIMALS. as to the existence or non-existence of the uterine mucous membrane in the human species and in cer- tain animals. From the examination of the elements which compose it, I came to the conclusion that it always does exist; that its most simple and funda- mental form is that of a more or less thick epithelial envelope; that its greatest complications depend on the elevation of the sub-epithelial connective tissue ; and that on this elevation depend the different forms of simple or highly festooned folds, which, notwithstand- ing their development, always represent the extremely small epithelial follicles which we had observed upon the uterine mucous membrane of other animals. Now I will pass on to the demonstration of the fact I ad- vance, and I hope thus to give a clear and exact idea of the formation of the maternal placenta, even in cases where that organ is single. On the internal surface of the uterus of the mare, which is covered with the most simple and element- ary mucous membrane, the new glandular organ, formed in pregnancy at term, represents, much en- larged, the small and delicate follicles which I de- scribed in the mucous membrane of the non-gravid uterus of the rabbit. Likewise, the new-formed glandular portion which is developed upon the per- manent part of the uterine cotyledons of the cow, which are also covered, in the state of non-gestation, by an elementary mucous membrane, assumes more complicated and more perfect forms, analogous, how- ever, to the types of those folds with multiple depres- sions which, like the simplest type, are observed upon the uterine mucous membrane of other animals in the state of non-gestation. SINGLE PLACENTA IN ANIMALS. 85 So far, then, the new glandular organ, or maternal portion of the placenta, follows in its character and in its development the same typical forms which we have observed in the uterine mucous membrane of various species of animals. Now, on examining the same organ in animals with a single placenta, which possess normally a uter- ine mucous membrane with double folds or with the most elevated form of structure of this membrane, we shall see that, in these animals also, nature does not change the type of neoformation, and that it only modifies and amplifies preéxisting forms. In short, when the mucous follicles, or folds, or linings of the uterine mucous membrane preéxist, in certain ani- mals, it is they which augment in number and vol- ume during pregnancy, and which take on special exterior forms, without losing the typical form of a simple glandular follicle. These facts sufficiently confirm what Leydig had supposed relative to the signification of the depres- sions or festoons of the folds of the mucous mem- brane in certain species of animals. This purely anatomical conclusion acquires even greater value, from an anatomical as well as from a physiological point of view, when applied to the study of the gravid uterus; for we are led to that other very im- portant conclusion, that the new glandular organ de- veloped during the pregnancy of animals is always the result of a transformation and perfecting of the uterine mucous membrane, without ever departing from the type which it presents in the normal condi- tion of the non-gravid uterus. The most simple forms of the placenta would be 86 SINGLE PLACENTA IN ANIMALS. those that Cuvier and Miller have described in cer- tain fishes. Now these forms likewise would not de- part from the general law established by my observa- tions. They would rather demonstrate the same fact in its simplest and most elementary expression. So far I have spoken of the single placenta in ani- mals. Although all my predecessors, even the most illustrious, have sought aid and light for the study of the human placenta from the observation of that of animals, I believe that such a method must have in- jured the truth and become the sole cause of a great many errors that have been propagated. In the hu- man species alone, the uterine mucous membrane never assumes, during pregnancy, the character of a more perfect membrane. Consequently, the new glandular organ which is developed differs greatly from that to be observed in animals. In woman, while preserving the fundamental and typical or characteristic parts of glandular organs, it loses com- pletely all the accessory features or form-characters which we meet with in the different species of other mammals. I have said this from the beginning, and I repeat it at this point, that it may be understood why I am obliged to treat separately of the human placenta and that of animals, though the organ is single in both cases. | The placenta of animals is emphatically distinct from that of the human species, both in structure and in the disposition of the parts. The demonstration of this truth will be, if I mistake not, the greatest and most interesting conclusion of this work. I should consider myself happy if, in spite of the nu- merous gaps that I am forced to leave, I could at SINGLE PLACENTA IN ANIMALS. 87 least fill up this one; and I should regard myself as more than happy, if it were granted me, at some future day, to produce the results of a comparative study between the placenta of the monkey and that of woman. Do we belong, from the first moments of our exist- ence, to the simian family, by the same placental structure, or, rather, does their placenta, like that of brutes, remove them from us, as we are already sep- arated by the structure of that organ from all other mammals ? | Is there among us any one who can answer this question, at once so important and so interesting ? Good-will and courage are not sufficient for this' kind of study ; our poverty deprives us of all hope in this direction, for the love of science, which consoles us, is very often the saddest and keenest of misfortunes for us!? But before describing the structure of the fully- formed single placenta in animals, I believe it will not be without profit to present some observations upon the placenta in process of formation, obtained by examining the gravid uterus of a rabbit between the ninth and tenth days of gestation. In speaking of the uterine glands, I have said that we find upon the mucous membrane of the rabbit numerous simple epithelial depressions, which I have called mucous follicles ; and in speaking of the differ- ences to be observed in the examination of the mu- cous membrane of different species of animals, I have called attention to the fact that the anatomical and physiological signification of these follicles is the 1 See the last paragraph of the Appendix. 88 SINGLE PLACENTA IN ANIMALS. same as that of the numerous and often greatly ele- vated folds of this membrane, whether they be fes- tooned or not. In studying the formation of the placenta, I shall also adduce proof of this assertion. At present, it will be well to inquire what becomes of the very small mucous follicles in the gravid uterus of the rabbit. In order that I may describe and explain, clearly as well as briefly, the observations made during this research, I make use of microscopic sections, rep- resented at two hundred and fifty diameters, in Plate VII. I dught to say, in the first place, that the uterine mucous membrane of the rabbit, between the ninth and tenth days of gestation, presents certain differ- ences, according as we examine it near the place where the placenta began to be formed, or in the por- tions of the horns of the uterus that remain empty. Near the placenta and in the portions of mucous membrane which, with the development of the foetus, will be covered, or, more properly speaking, will be transformed into a placental organ, this membrane appears enlarged and tomentose. Examined with the microscope (Plate VII., Fig. 1), we see that this appearance is due to a remarkable development of those small follicles that I have indicated by the let- ters a, a. They are so close together that in the vertical sections of the figure we find several of them cut through at different points of their course (e, c). Around each of them we remark the proliferation of the connective tissue which forms the external wall of each follicle (d, d), and all around, as well as inter- SINGLE PLACENTA IN ANIMALS. 89 nally, the abundant formation of the epithelial element which is the essential part of all glandular organs. These same follicles, which we have seen so small in the non-gravid uterus, have acquired from 0.10 to 0.15 mm. in diameter, and from 0.22 to 0.30 mm. in length. Such hypertrophy at the place indicated is remarkable, for the outer edges of the growing pla- centa are made up of elevations or folds of the mu- cous membrane, which have on their exterior very apparent notches or festoons. In short, it is the outer edge of the last peripheral follicle, comprised in the formation of the placenta, which has been transformed into a festooned fringe of mucous mem- brane. The vertical section of portions of the horns of the uterus that have remained empty allows us to see, instead of the simple development of the follicles, the mucous membrane rising and forming very promi- nent folds, which diminish more and more as they ap- proach the enlargement of the horn where the ovum is arrested. On examining these folds with the mi- croscope (Plate VII., Fig. 4), one is struck with the elegant figure presented. It seems difficult at first, to get a clear idea of the intimate structure, from the cut represented in the above-named figure; but on looking more attentively, we easily perceive that it is produced by cup-like or tunnel-shaped elevations of the mucous membrane, pressed close together and having an undulating course, coiling themselves to- wards their free surface. I shall soon return to the anatomical and physiological signification of these projections or complicated folds in the gravid uterus of the rabbit. The important point to be ascer- 90 SINGLE PLACENTA IN ANIMALS. tained in the formation of the placenta is what has become of the follicles, so highly developed, which we saw in close proximity to the placenta at the be- ginning of its organization. For this study, the transverse sections of the pla- centa have seemed to me most useful for the pur- pose of demonstration. Figure 2 of Plate VII. shows a section from the placenta of the rabbit in process of formation, near the uterine surface. The large openings, limited internally by epithelial cells (a, a), already indicate the remarkable calicular expansion which the follicles have speedily acquired at the spot where the placenta is formed. The placental base, consequently, has been formed by the development of the follicles, and by a very abundant proliferation of the sub-mucous connective tissue of the uterus (¢,¢). It is not uncommon to find in this part of the placenta, that some of the follicles, closely crowded against each other (4), have blended their walls to- gether. In such cases, I have always observed that around the follicles in which the internal cavities, though contracted, were preserved, the transforma- tion of the connective tissue into epithelial cells was more active throughout the whole interior of such cavity, — a fact which is not observed in the preced- ing case. In Figure 3 of Plate VII. I have represented another transverse section of the same placenta, but close to the foetal surface. Here the cup-like cavities are seen rather narrower than at the base, and the form of already developed tubes predominates (a, a). I believe that this results from the sinuous and undu- lating course of the superior border of the calices which have grown out of the enlarged follicles, and SINGLE PLACENTA IN ANIMALS. 91 which by frequent contact blend their walls together and form almost as many crowded and slender tubes which open upon the foetal surface of the placenta.’ Indeed, from vertical sections of this part of the placenta in process of formation, we see by the mi croscope that the foetal surface is entirely covered with tracings, and that it has a tomentose appearance like a sponge. At the aforesaid period of pregnancy in the rabbit, we already perceive the openings of the tubes or canals which are nearly formed, and are filled with small oval cells, colorless and very trans- parent. When the vascular villi of the chorion are completely developed, they will find the openings of the glandular organ ready to receive them. Between the foetal surface of the placenta in proc- ess of formation and the neighboring part which 1 have had drawn in Figure 3 of Plate VIL, there is not only the difference that I have indicated in relation to the great number of orifices of the glandular folli- cles, crowded close together, but there is the further difference of a smaller quantity of true connective tissue interposed, having here rather the character- istics of a gelatinous substance than of an aggrega- tion of corpuscles of connective tissue. Hence the spongy and tomentose form noticed above. When the vascular villi of the chorion are formed and have penetrated into this gelatinous tissue, there are or- ganized large round cells, analogous to those of which we shall see the membrana serotina composed in the human species. They are neutral cells, which, by their multiple and rapid transformations, serve to perfect and complete the structure of the normal pla- 1 See Appendix. 92 SINGLE PLACENTA IN ANIMALS. centa and to establish an intimate relation with the utero-placental connective tissue, by means of which it is blended with that of the chorion. We shall see presently, more clearly, that these same rudimentary parts are preserved, with the ex- ception of some difference of form, in the completely organized placenta. But I wish first to direct your attention to the projections or folds of the mucous membrane which I have described in the unoccupied portions of the uterine horns; for it appears to me that they give better than any description a precise idea of the internal skeleton, so to speak, of the glandular organ or maternal placenta of animals with a single placenta. In a word, these folds of the mu- cous membrane (Plate VII., Fig. 4) are the rudiment- ary portions of the glandular organ or maternal part of the placenta, which has been arrested in its devel- opment, solely because the fecundated ovum has fixed itself at another point. This fact offers another quite important consideration for the physiologist, namely, that at the rutting period, and, still better, after fe- cundation, the whole internal surface of the uterine horns is prepared to be transformed into a placenta. This ought naturally to be the case, the point of the uterus where the ovum is to fix itself not being de- termined by any law. In the parts which form the glandular or maternal portion of the placenta, there take place successively other important transformations, which are established when the vessels appear in the foetal villi of the cho- rion, and when the neutral cells above referred to are formed. I do not insist upon this point, which is not yet sufficiently studied, and which, consequently, SINGLE PLACENTA IN ANIMALS. 93 opens, it seems to me, a large field for observation. The description of the development of the placenta in all its successive phases and transformations has appeared to me worthy of quite special study. The little that I have said, therefore, may suffice for the present as a help towards understanding the gland- ular structure of the completely formed maternal placenta. Among those of the carnivora that I have been able to examine, the placenta of the dog has seemed to me most suitable for demonstrating easily and clearly the glandular structure of the fully-formed maternal portion of the placenta. In dogs as well as in cats, we do not find the uterine mucous membrane disposed in extremely small follicles, but in more or less elevated folds. In these animals, however, the placenta is formed in the same manner as when the follicles do exist, as observed in the rabbit. The only difference is that as there are no follicles in the uterus of the dog and of the cat to be enlarged, we find instead an enlarge- ment in the excavations or festoons of the mucous membrane, which are nothing but highly developed follicles even in the condition of non-gestation. The elevation of the folds of the mucous membrane is seen quite plainly at the edges of the placenta in the cat and the dog, where we also easily perceive that the festoons of the inner side of a fold of mucous mem- brane, which face and touch the placenta, coalesce with it, while those of the outer side of the same fold remain entirely free. In making vertical sec- tions of the uterus and placenta of the dog or of the cat, after having hardened them in alcohol or diluted 94 SINGLE PLACENTA IN ANIMALS. chromic acid, it often occurred that I cut through united folds of mucous membrane, which had re- mained within the placenta without being trans- formed into a glandular organ, like those folds which touched immediately the internal parts of it. This fact proves also that the folds in question penetrate into the interior of the placenta, and there unite with each other. | This description is made clear by Plates VIII. and IX. | By detaching the placenta at the point where there is no penetration of considerable folds, and where, consequently, its relations with the uterus are the slightest; by making transverse incisions upon this face of the placenta, about half a millimeter in thickness, and examining them with the microscope, we easily distinguish glandular cavities, cut trans- versely and of different dimensions, which are only culs-de-sac of so many depressions in the folds of the mucous membrane. The internal epithelium which coats them is composed of agglomerated cells united in various ways; hence result the most dissimilar forms. In the vertical sections, also, these glandular organs are found cut more or less transversely, and we may conclude from this that their course is sin- uous (Plate IX., Fig. 1, d, d)2 On the ii in ine superior or foetal ‘eee of: the placenta, whatever may be the direction of the cut, we always see a uniform net-work of tubes, hav- ing an irregularly sinuous course, often communicat- ing with each other by means of very small commis- sures (Plate VIII., Figs. 1 and 2, a,5). Having reached 1 See Appendix. SINGLE PLACENTA IN ANIMALS. 95 the surface of the chorion (Plate VIIL, Fig. 1, c, c), these tubes terminate in openings of variable diam- eter, according to the number of tubes that are con- fluent into one opening. This fact, which is easily observed by using vertical sections from the foetal surface of the placenta of the dog, has not been re- marked by any one, unless Haller may have had reference to it when he wrote: “In cane dum villo- sum chorion, foraminulentum et reticulatum, detrahe- bam, succus serosus defluxit, et alius sanguinis suc- cessit.”* In any case, I have satisfaction in quoting these words of the illustrious physiologist ; for though brief and ambiguous, they have, I think, an important bearing upon the observations that I have just pre- sented to you, notwithstanding the utter neglect in which they have been left. The villi of the chorion penetrate into the orifices of the above-named sinu- ous tubes. It now remains for us to ask what the relation is between these tubes and the glandular organs formed by the enlargement of the depressions between the folds of mucous membrane which, as I have pointed out, are seen upon the uterine surface of the placenta by both vertical and transverse sections (Plate IX., d, d). Vertical sections are very useful for this purpose. At the bottom of Plate IX., a, a, is represented the connective tissue of the uterus, which, having become elevated by proliferation, has lifted higher the large festooned folds of mucous membrane, whose extrem- ity or cul-de-sac is represented at d, d, with magni- fied volume? The walls of these festoons or follicles, *MOpu Cit... t. vili, p. 248. 2 See Appendix. 96 SINGLE PLACENTA IN ANIMALS. already transformed into glandular organs, become blended together and go to make up larger cavities, surrounded by a peculiar layer of epithelium, which, as it is detached, forms a milky fluid that coagulates in alcohol. This fluid fills certain parts of the cavity into which it is poured. Upon the superior walls of these cavities open the tubes of which I have spoken (e,e); or, to speak more properly, these walls are con- tinuous with those which form the external wall of the tubes, while the internal cellular wall of the cav- ity is continuous with their internal wall. The villi of the chorion, the foetal placenta, do not penetrate into the inferior glandular cavities of the placenta, formed by the folds of the mucous membrane. These observations probably explain how Eschricht and Bischoff may have confounded these glandular cavities with the dilatations of the utricular glands that I have represented at 0, 6, and how from the sinuous progress of the villi of the chorion within the winding canals of the glandular tubes may have also arisen the idea of lamine constituting the foetal pla- centa of the uterus, crossing and meeting each other in different ways (Plate VIII, Fig. 2). The fact is that, even in the case of single placenta in animals, it is the mucous membrane that is transformed into a glandular organ; and this organ does not lose the type of simple glandular follicle, merely because one part of the follicles has a singularly flexuous arrange- ment and because they communicate with each other (Plate VIII. Figs. 1 and 2, e, e), We always find the form of a canal or tube, at one extremity of which is the orifice, the other terminating in a cul-de-sac, in which is inclosed a vascular loop of the chorion, SINGLE PLACENTA IN ANIMALS. 97 charged with absorbing the fluid resulting from the internal epithelial product of the glandular follicle.’ Even in the cases of single placenta, the maternal portion of it is glandular and the foetal vascular. The relation between these parts is more complete than where the placenta is multiple or disseminated, but there is very little difficulty in referring the structure back to its most simple and elementary forms. To convince ourselves of this, it is only nec- essary to examine Figure 1 of Plate IV., representing the structure of the placenta of the mare, and com- pare it with those which have served for the fa tion of the placenta of the dog. The same structure is i in the placenta of the cat; but for the descriptions as well as for the drawings, I have preferred that of the dog, because the greater volume of the parts in this animal ren- ders observation more easy. Now, on bringing together these observations, drawn from researches made upon the placenta dur- ing its development, the connective link which unites the different parts described is obvious. The base of the placenta in process of formation (Plate VIL, Fig. 2) corresponds entirely to what I have described and drawn in Plate IX., d4,d. The glandular tubes, already formed, represented in Plate VIII., Fig. 2, correspond to those that I have had drawn in process of formation in Plate VII., Fig. 3. Finally, the su- perficial, perforated, and spongy layer that I have described in the growing placenta is found indicated 1 For greater clearness compare the diagram of the placenta of the dog (Plate I., Fig. 3) with the microscopic sections described and represented (Plates VIII. and IX). 7 98 SINGLE PLACENTA IN ANIMALS. in the fully developed placenta represented in Plate VII, Wig. 2; | It is generally thought that in the delivery of these animals the foetal as well as the maternal por- tion of the placenta is expelled from the uterus, and that there is consequently a true traumatic lesion; and for this reason Weber’ proposed to divide the mammalia into two classes, according to the mode of separation between the two parts of the placenta, at the moment of parturition. In the first class he comprised all those animals in which the placenta are united so slightly that they separate without pro- ducing in the uterus the slightest traumatic lesion, as in the ruminants. In that case, according to him, the maternal placenta remains in the uterus, simply decreasing in volume. In the second class he placed the animals in which the two placenta are so clearly united that, at the moment of parturition, the uterine is detached at the same time as the foetal, so as al- ways to produce a traumatic lesion of the uterus. Among the latter he classed the carnivora, the rodents, and woman. For them all, the single placenta is only a caducous organ, which must be reproduced at every pregnancy. | Such a view of the subject, though adopted by the most learned anatomists and physiologists, is utterly incorrect. We have seen, beyond the possibility of doubt, how, in the solipeds, the maternal portion of the placenta, which is disseminated or diffused over the whole internal uterine surface, not only dimin- ishes in volume, but is entirely destroyed, and disap- 1 Froriep’s Notizen aus dem Gebiete der Natur und Heilkunde, No. 996. 1855. SINGLE PLACENTA IN ANIMALS. 99 pears after delivery; and how the same thing occurs to the portions of the cotyledons which are devel- oped during the pregnancy of those animals in which the cotyledons of the non-gravid uterus indicate only the points where the neoformation of the maternal placenta will take place during pregnancy. It fol- lows from these observations that in all cases, without exception, the maternal placenta is a caducous organ at the moment of parturition or afterwards, and that it must be reproduced at every pregnancy. As to the traumatic lesion of the uterus, admitted by Weber for the carnivora as well as for woman, I must repeat that such an assertion is also entirely incorrect. Examining, indeed, the uterus of dogs at different periods after delivery, we observe certain things wor- thy of attention. In the uterus of a dog killed two hours after parturition, I found the cavity noticeably stained by a fluid or mucus of a dark green color. This coloration is produced by the green matter elab- orated in great quantity, as I have said before, by the epithelial cells of the great folds of mucous membrane which surrounds the placenta. And what becomes still more important is that it is these very elevated folds that remain in the uterus and circumscribe the place where the placenta was formed, and this place, instead of being denuded by the loosening of the placenta, is found covered, on the contrary, with a layer which, from its external appearance, one would take for a thickened mucous membrane, in continuous relation with the folds which limit the placental re- gion. This is sufficient to show that traumatic lesion of the uterus in animals with a single placenta is very 100 SINGLE PLACENTA IN ANIMALS. slight and very limited. The appearances are differ- ent if we examine the uterus of those animals two or or even six days after delivery. Then the green sub- stance has disappeared; and, in the contraction of the uterus returning to its normal volume, the thick- ened mucous membrane which I remarked at the places where the placenta had been formed is found changed into numerous folds, close together, much elevated, and rather thin. What the membrane of which they are formed has lost in thickness, they have gained in length. The folding into close-lying fringes is the effect of the remarkable diminution in the size of the uterus. I was not able to repeat the observation until thirty days after delivery. The place where the placenta had been formed was still indicated by a thin, blackish crust, about as large asa penny. ‘The animal which had served for the examination was of medium size. It is then demonstrated that the large folds of uterine | mucous membrane which rise at the edges of the pla- | centa and contribute to its function with their inner- | most portion, as well as the strong layer, like thick- | ened mucous membrane, which occupies the whole | place where the placenta were organized, gradually | change and disappear, in order to make way for the production of the mucous membrane proper to the | non-gravid uterus. Briefly, in delivery it is the new | portion of mucous membrane transformed into a pla- | centa which is detached. The old mucous membrane | remains, in a thickened condition, undergoing as a | consequence of the uterine contractions the modifi- | cations indicated, to be at length slowly destroyed | altogether. SINGLE PLACENTA IN ANIMALS. 101 Now, on observing the large folds on the second and even on the tenth day after parturition, it has seemed to me that their progressive destruction is accomplished by means of a special and limited fatty degeneration. In this observation, as in the others which I have placed before you, I am forced to leave many deficiencies, on account of the serious difficul- ties to be encountered at each step in this kind of in- vestigation. I have not liked to pass over in silence the little I have been able to do, because, with the paucity of observations that we have on this subject, the facts stated may, in some degree, aid us to com- prehend how occurs after delivery the destruction of the glandular organ over the whole uterine surface of the mare and in the glandular portion of new for- mation of the uterine cotyledons of the cow, and may greatly modify the opinions at present enter- tained on the subject. Even from Weber’s point of view, man cannot be confounded with the animals. The traumatic lesion of the uterus, in consequence of delivery, either does not exist, as in cases of disseminated or multiple pla- centa, or it is very slight, when the placenta is sin- gle, as I have demonstrated in the dog. In woman only delivery produces a true and considerable trau- matic lesion of the uterus. This is what I am about to demonstrate, in passing to the description of the structure of the human placenta. CHAPTER VI. THE HUMAN PLACENTA. I HAVE several times stated that the structure of the human placenta differs greatly from that of the mammiferous animals, even those having a single pla- centa, not only in the shape and the disposition of its various parts, but in the manner of its formation and of its separation from the uterus in delivery. Not- withstanding these remarkable and important differ- ences, there exists also in the human placenta, as in the placenta of all mammals, the glandular organ of new formation, constituting the maternal portion, which is brought into direct relation with the villi of the chorion, that is to say, the foetal placenta. The real cause of all these differences is to be sought in the phenomena which are produced at the surface of the uterus upon which the placenta is formed, in order to give rise to the neoformation of the glandular organ; in the manner in which the villi of the chorion are brought into relation with this same organ ; and, finally, in the mode of distri- bution of the utero-placental vessels in the human placenta. The most notable modification that takes place upon the uterine surface, at the point where the pla- centa appears, is connected with the formation of the membrane called decidua serotina, a membrane THE HUMAN PLACENTA. 103 which is lacking in animals.’ In the latter, the devel- opment of the maternal or glandular part depends upon a direct metamorphosis of the uterine mucous membrane. But before inquiring into the intimate structure and functions of the membrane in question, it will be proper to quote in the first place a few of the numerous opinions that have been held, both as to the mode of formation and as to the structure of the true or uterine decidua. I shall speak particularly of those only which can aid me to demonstrate the very great importance that the decidua serotina has in the formation of the placenta and for the nutrition of the human foetus. It is this point, I think, which deserves the most attention. As to the mode of development and the relations of the decidua to the ovum, we encounter wide diver- sities of opinion. According to the observations of the most modern physiologists, of Vierordt, for exam- ple, the ovum, after its entrance into the uterine cav- ity, adheres to some point of the mucous membrane ; the membrane then swells around the ovum, embraces it like a capsule, and makes a nest for it, as it were, or constitutes, as it is named, the internal or reflected decidua. This mucous capsule enlarges along with the ovum more and more, and at the third month it becomes attached to the uterine mucous membrane which is covered with the external decidua ;? blended with the latter, it then makes but one single mem- brane, which gradually loses its vascularity. Formerly, it was believed that there was an entirely 1 See Appendix. ? Vierordt would prefer the terms external and internal decidua to those generally employed, uterine or true decidua and reflected decidua. | 104 THE HUMAN PLACENTA. different process. It was supposed that the uterine orifices of the Fallopian tubes became obstructed by the tumefaction of the mucous membrane, and that this membrane then enveloped the ovum at its en- trance into the uterus. Consequently, that part of the mucous membrane which, pushed by the ovum in its passage from the tube to the uterus, was folded back upon itself and thus enveloped the ovum di- rectly, was distinguished as the reflected decidua. This was the mucous capsule of Vierordt. The true decidua was formed by the portion of the uterine mucous membrane not folded back, which thus rep- resented the external layer of the envelopes of the ovum. The principal opinions held afterwards as to the structure of the membrana decidua in the human species are reduced to the following: it is either an- histous, analogous to the products of exudation or to pseudo-membranes ; or else it is a special, organized membrane. Among the partisans of the latter, we must distinguish those who believe that the decidua is formed by a sort of tumefaction or expansion of the uterine mucous membrane (“ membrana uteri in- terna evoluta,” as Seiler says), granting to it an organ- ization and vessels, from those who, after the teach- ings of Weber, claim, with Bischoff, that the decidua is made up from the layer of the internal glands of the uterus, in. the midst of which are found numerous vessels with an exuded, plastic matter, which is so in- timately united to the internal uterine mucous mem- brane that it seems to form one and the same struct- ure. This idea appeared to be well supported by the observation of the fact that by compressing the THE HUMAN PLACENTA. 105 walls of a gravid uterus we see the fluid burst forth from the utricular glands and from the numerous ori- fices with which the surface of the decidua is pierced, when it is completely detached from the uterus. These facts seemed to show the continuity of the glandular canals with the decidua. In speaking of the uterine glands, I have noted how in the decidua of the ruminants, which has the form of a thin epithelial envelope, we observe certain small opercula, found upon the external surface of the chorion, and which correspond to the orifices of these uterine glands. In the human species, on the contrary, the epithelium of the mucous membrane and that of the uterine glands mingled with the or- ganizable substance constitute the thick membrane called decidua; the latter adheres to the internal epithelial surface of the uterus, and the glandular se- cretion is so active and so continuous that it keeps the orifices of the glands open through the decidua. These numerous openings in the decidua give to it, when it is detached, the appearance of a membrane pierced like a sieve. During menstruation, there is also organized a spe- cies of decidua, sometimes quite remarkable, named catamenial decidua, which is always highly developed after conception.’ Such facts led Hunter, Seiler, Shar- 1 Quite recently the changes which the mucous membrane of the uterus undergoes during menstruation have been carefully studied by a number of good observers. Dr. J. H. Aveling published an article in the Obstet- rical Journal of Great Britain and Ireland in July, 1874, upon Nidation in the Human Female, which process he defines to be the periodical for- mation of the membrane lining the body of the uterus, which is devel- oped during the inter-menstrual period, and is dependent upon ovulation. He states that, the nidal decidua having reached its full development, 106 THE HUMAN PLACENTA. pey, and Weber to affirm that the uterine mucous membrane is already prepared during menstruation and no impregnated ovum having arrived to demand from it protection and sustenance, a process of degeneration takes place, its attachments are loosened, and it is expelled by the contractions of the uterus, some- times whole, in the shape of a triangular sac, but more frequently in mi- nute portions. How long this process occupies has not been determined, but it is probably completed during the menstrual period. The act of denidation probably determines that of menstruation, because it is from the denuded surface of the uterus, caused by the removal of the nidal decidua, that the menstrual flow comes. Dr. John Williams published a very interesting article in the same jour- nal for March, 1875, in which he claims that there is no interval of uterine rest, but that the nearest approach to this condition is during the flowing, when the mucous membrane is undergoing disintegration. Even then the subjacent muscular wall is in a state of active preparation for the forma- tion of a new mucous membrane. Menstruation, according to him, is pro- duced by a process of fatty degeneration of the uterine mucous membrane, always commencing just within the internal os, and gradually extending to the fundus. The time necessary for the removal of the membrane varies in different individuals. Disintegration not only extends to the glandular and mucous elements, but includes the walls of the superficial vessels, so that a lesion occurs and hemorrhage takes place. The devel- opment of the new mucous membrane follows the destruction of the old pari passu, and is completed in abouta week. This, he declares, is formed from the uterine wall direct, ‘muscular fibres producing the fusiform cells, the connective tissue the round cells, and the groups of round cells in the meshes formed by the muscular bundles the granular epithelium.” Dr. George J. Engelmann, of St. Louis, in an article published in the American Journal of Obstetrics, May, 1875, denies that processes occur such as Aveling and Williams describe. From carefully repeated micro- scopic studies he shows that the mucous membrane during menstruation is swollen; that its surface is puffy and wavy, and after removing the mucus it becomes more distinctly visible; and in vertical sections the glands themselves may be seen without the aid of a lens in their entire length as white stria. The microscopic changes of the membrane are equally noteworthy, showing a remarkable proliferation of cell character, producing hyper- trophy of its superficial layers, and raising its surface about the ostia of the glands, so that they appear like funnel-shaped depressions. The glands, except at their fundi, are very much enlarged, often two and four fold. ‘¢ The facts gathered warrant the conclusion that the mucous membrane THE HUMAN PLACENTA. 107 to receive the ovum, and that after conception it is transformed into the external envelope of the ovum. Now if, according to the preceding observations, the uterine or true decidua is only a product of ex- udation, due in great measure to the secretion of the uterine glands and to the transudation of organizable fluids from the internal surface of the uterus, it be- comes easy to comprehend the formation of the re- flected decidua which has been the object of so many discussions among anatomists. While the whole in- ternal surface of the uterus is covered with the uter- ine decidua, the ovum when reaching the uterus is also covered with a similar layer, formed by the same materials which further serve to fix it at some one point of the uterus. At this point the uterine and the reflected deciduz are soon mingled together, pre- cisely as will take place later, when the ovum, increas- ing in size, forces the reflected membrane which sur- rounds it against the uterine decidua, so that the two deciduse blend into one single membrane. The uterine and the reflected decidu@ are com- posed then of the organic materials elaborated by the internal surface of the uterus, and by the uterine glands. These products serve to nourish the ovum of the womb begins to increase in thickness as the time of menstruation approaches; that this tumefaction is most marked during the period itself, and gradually decreases after the cessation of the catamenial discharge. The hemorrhage in the menstrual womb is always confined to the sur- face of the lining membrane, and the fatty degeneration is likewise more marked in its upper layer.” My own studies confirm me in the belief that the conclusions of Dr. En- gelmann are correct, and that the uterine mucosa does not depart in its function physiologically from that of other mucous membranes in such an extraordinary manner as to destroy itself and be regenerated at every normal menstruation. — H. O. M. 108 THE HUMAN PLACENTA. before the formation of the glandular organ, with which the villi of the foetal placenta will be brought into relation when they shall have become vascular. This easily explains the fusion of the two decidua. The uterine decidua is probably thus developed in the human species, because the uterine mucous mem- brane does not rise in numerous and distinct folds, constituting enormous open glandular follicles, as it does in animals; it is by reason of this that in the latter a species of rudimentary placenta is formed from the first moments of conception, and perhaps from the time even that the rutting season begins. But if all this is not difficult to understand, and is confirmed by more or less exact observations of illus- trious authors, the same cannot be said for the deci- dua serotina, which, according to some, is simply the place or point where the two decidue have come in contact with each other, to fix the ovum against the wall of the uterus. The ancient anatomists remarked that the uterine surface of the human placenta is rendered uneven by the presence of elevations or rounded lobules, crowded together. Arantius* taught that this placental sur- face, called by him fungous, was covered with a deli- cate, thin, and whitish membrane. Fallopius? believed this membrane to be formed by an agglutinant mat- ter. Bojanus afterwards called it membrana serotina, and others utero-placental plate. No modern author denies its existence; but no agreement has been arrived at as to its formation and function. It has been called a subtile lamina of 1 Arantius: De Humano Feetu, cap. 10, p. 71. 2 Observ. Anatom. in Operibus Vesalei, page 754. THE HUMAN PLACENTA. 109 the uterine decidua, having the same structure as the latter. Some attribute vessels to it; others dis- pute their existence. It has been claimed that it served to unite the placental lobes or cotyledons, and the idea has been sustained that it penetrated not only between the cotyledons, but also between all the vascular filaments. Some have supposed that it is to be met with in all the periods of gestation ; others, that it exists only during the last three or four months. According to Haller, Rouhault! was the first to observe that the serotina extends as far as the concave or foetal surface of the placenta, through the clefts to be seen upon its uterine or convex sur- face. Hobokenius noted that the chorion, which cov- ers the placental furrows and descends into them, serves to unite the lobes of the placenta with each other.2 Thus we find that the chorion and the de- cidua serotina have been confounded.’ About thirty years ago, Burns’ maintained that the placenta was the result of the mingling of the uterine vessels with the external layer of the mem- brana decidua. Miller® claims, that the uterine placenta of woman is formed by the development of the decidua, 1 Rouhault denied, without reason, a membranous structure to the serotina, because it is pierced with numerous holes which allowed pas- sage, as he thought, to a great number of vessels. (Mém. de I Ac. R. des Sciences, page 182. 1714.) 2 Anatomia Secundine Humana Repetita, page 113. Utrecht, 1675. 8 Noortwyk believed for some time that the observation of Hoboke- nius was exact, but he afterwards denied it altogether. (Op. cit., p. 153.) 4 « Frequentissime etiam a partu; latas lacinias chorii reperio quae in utero, manserint.”’ (Haller, op. cit., t. viii., p. 235.) 5 Medical Gazette of London. PRO pw Cit. til, p. 781. - - — ide eee @-——r"u e na 7 110 THE HUMAN PLACENTA. which enlarges towards the foetal placenta and in- sinuates itself between the bundles of its villi, so as to join the internal surface of the chorion. He adds that the structure of the decidua serotina or sec- ondary decidua is analogous to that of the true de- cidua.! Vierordt does not depart very far from these as- sertions when he writes that “at the part of the chorion which faces or touches the wall of the uterus, the villi are developed; and that upon the uterine surface are formed the corresponding portion of the decidua, and the sanguineous vessels of the mother. From the fibro-muscular layer of the uterus,” says he, “ depart numerous small arteries which are dis- tributed to this portion of the decidua, there branch- ing off into capillaries; then their walls become more and more attenuated, and finally they disappear. During this period, the part of the decidua which has been often called decidua serotina is found riddled by areoli or cavities which contain blood, and which develop to such a degree that there remains almost nothing of its primitive and fundamental conforma- tion.” ? Thus it appears that the uncertainties which pre- vail in science as to the decidua serotina are very great, | In order not to have dwelt so long upon the sub- Ject to no purpose, I shall now explain my general idea concerning this membrane, as I have already done upon the uterine and the reflected decidue. I 1 Op. cit, 4. i, p.o714. 2 Fisiologia dell’ Uomo, page 789. Milan, 1862. THE HUMAN PLACENTA. wit have said that the place where the ovum is arrested is also the point where, in the beginning, the two de- ciduz come in contact and are blended, however thin the reflected membrane which surrounds the ovum may be at that time. Every one knows that it is here particularly that the villi of the chorion are de- veloped, which are at first the only means by which the ovum absorbs the nutritive elements from the materials that surround it. Not only do these villi increase greatly in magnitude, but they also become more complete, a fact due to the vessels proceeding from the allantois which traverse them. Absorption ought to be, consequently, very active at this point; and it is proved that this is the fact by the considerable development of the villi. It fol- lows that here especially the component elements of the decidue are more rapidly absorbed than else- where. During this time, the connective tissue of the subjacent internal uterine surface proliferates, and is transformed to such a degree as to constitute the most marvelous tissue known in the animal or- ganism. The structure of the decidua serotina is, as we shall observe, so peculiar as to prevent its being con- founded with the uterine and the reflected decidu®, a confusion which has been almost universal to the pres- ent day. We shall further see in the sequel, that in addition to very remarkable peculiarities of structure, the serotina ought to be considered as the stroma of the glandular organ or maternal portion of the pla- centa. For such is the noble and important fune- tion which nature has intrusted to this membrane, to which anatomists and physiologists have always at- 12 THE HUMAN PLACENTA. tached so little importance; I shall continue to call it the serotina so as not to cause confusion by introduc- ing a new nomenclature. Before giving you my own observations, I ought to fulfill the duty of historian. I shall do so with all the more pleasure because in quoting the microscopic ob- servations of Robin! and of Pouchet ? upon the struct- ure of the decidua serotina, it will be necessary to give the earliest researches that were made upon this subject, and that have not yet been repeated by other observers. Though incomplete, they support those that I shall myself offer you. Robin regards the grayish membrane which is seen upon the uterine surface of the placenta, and which is buried between the cotyledons, there augmenting in volume, as a portion of the decidua. This mem- brane, he thinks, is visibly continuous with the por- tion of the decidua which adheres to the chorion. The grayish tissue which forms it contains: first, an amorphous matter; secondly, molecular granulations of different nature ; thirdly, cells which have under- gone a considerable hypertrophy and which present the most diverse changes, simulating all the known and described varieties of cancerous cells. To dis- cover these cells, which have all the characteristic elements of cancer, it is only necessary, he adds, to scrape the uterine surface of a fresh placenta with the blade of the scalpel, and to examine with the micro- scope the pulp thus obtained. These epithelia so entirely altered are, however, 1 Mémoire sur quelques Points de l’Anatomie et de la Physiologie de la muqueuse Uterine. Paris, 1858. ? Précis d’ Histologie humaine, page 359. Paris, 1864. THE HUMAN PLACENTA. 1015 only normal elements or cells of the uterine mucous membrane that have undergone, in the midst of a normal tissue, physiological modifications which such elements ordinarily present, in the animal economy, only under a pathological influence. The nutrition of the foetus is carried on by means of an endosmotic interchange through this grayish layer which consti- tutes the decidua serotina. The results of the observations of Robin! are exact only in part, namely, in what relates to the existence of very singular cells in the decidua serotina. All the rest is erroneous, as I am about to demonstrate. I have stated that the decidua serotina is distin- guished from the true or uterine decidua and from the reflected decidua by anatomical characters. In order to prove what I have advanced, I shall begin with the study of the placental villi, because in in- vestigating the intimate structure of these and their relation to the decidua serotina, I shall necessarily describe the structure of the latter, and so better ex- plain its functions. The ancients were aware that the placental villi, which they called branching fibres, were surrounded with something that most authors were content to call a cellular web. Hobokenius spoke of it as nervous substance ; Needham said that it was gelatine: “In gelatinam leutam et multis in locis glandulosam con- crescit ut difficilius a vasis separari possit.”? Stuart called it a special carneo-spongy substance. Haller considered that “cum truncis vasorum advenit, qui- 1 Dictionnaire de Médecine, etc. Tenth edition. Paris, 1858. Art. Placenta. Op. cit.) p. 84. 8 4 THE HUMAN PLACENTA. bus est pro vagina, indeque ad minimas usque fibrillas comitatur;” and according to Albinus, “ altera super- est tenerior cellulositas qua a chorio propagata vas- cula singula obvolvit.” Thus he concluded that the placenta was composed only of vessels and of the cellular web. As to the function of this web, he contented himself with af firming that there were “ clarissimi viri, qui ex utero sanguinem malunt in cellulosam tetam deponi indeque per venulas placente resorberi.” * In the works of the moderns we find that it is a denser, more fragile, and less regular layer of the utero-placental plate ; and that it surrounds the vas- cular trunks. This led some among them to believe that the placental vessels were diffused throughout the thickness of the decidua itself, or that the chorion was composed of several sheets or leaves; that the decidua or anhistous membrane sent one leaf to the external surface, and another to the foetal surface of the placenta; and that the delicate pellicle formed by the latter was folded between all the lobes, lob- ules, and vessels of the placenta. We vainly seek in recent works for fuller informa- tion upon this subject. We must except, however, that given by Farre,? which it is well to present, as I have not seen his opinion upon this matter quoted by any one. According to him, each villus is com- posed of two distinct parts; that is to say, of an ex- ternal membranous layer, and of a softer and vascu- lar internal tissue, which is introduced into the other tOpwetts,spue2 4. 2 Farre, Arthur: the article, Uterus and its Appendages, from the Cyclopedia of Anatomy and Physiology, page 718, fig. 485. London, 1858. | i THE HUMAN PLACENTA. ES like the fingers ina glove. The distinction between these two tissues is not easily observed, except in cases where the external layer is torn, leaving the in- ternal substance exposed, or in case it happens that the placenta remaining for some days in the uterus and undergoing changes there, its internal part shrivels and separates from the external wall, so as to leave a small space between them. On examining a villus microscopically, we see that the external layer is formed by a transparent membrane, amorphous, and non-vascular, in which are set, or attached to the internal surface, numerous spheroidal cells, slightly flattened, forming a single layer. The internal portion, according to Farre, is formed of a soft and pulpy tissue which envelops the blood- vessels of the villi, and in the midst of which are found inclosed other numerous cells of the same nat- ure as those which exist upon the internal surface of the external layer. About ten years afterwards Vierordt, without be- ing aware of the observations of Farre, confined him- self to teaching that the villi are formed by a vascu- lar loop of connective tissue, and covered with an epithelium which would favor, he thought, the endos- motic exchange with the blood of the mother. But Farre does not inquire into the origin of the external layer of the villi which he had in part so well described; and even while saying ! that the villi come from the chorion and extend to the decidua, in which they become implanted and adhere as far as they penetrate into it, he excludes what is really ob- served in the phenomenon, namely, that it is the de- Loc. cit. ps 719. SSSA SSS assess aS SY Somes 116 THE HUMAN PLACENTA. cidua serotina, which is prolonged over the villi, en- wraps them all, and accompanies them even to the chorion. To proceed in an orderly manner, I will now state what I have seen in the study of the villi. The ob- servations of Farre are entirely exact, and confirm the doctrines of the ancients upon the cellular web, or external membrane, which surrounds the villi throughout their whole extent (Plate X., Fig. 2, b,b). By employing the customary processes of im- bibition it is easy to perceive that, in placenta at term at least, the cells are not inclosed in the sub- stance of the membrane, but that they form, on the contrary, a species of epithelial layer which lines the whole internal surface of it. Exercising suitable pressure upon portions of the villi, it often occurs that the wall which surrounds the vessels, whence proceed the smaller villi, is torn. In this case, the epithelial layer, formed by the above-named oval and granular cells, is very easily perceived. I have never succeeded in meeting with such cells in the diapha- nous substance that surrounds the vessels of the villi, in which, however, are clearly distinguished the fusi- form cells which make a part of it (Plate X., Fig. 2, a, @). | | I have stated above, that the exterior membrane surrounding the villi throughout their whole extent is furnished by the decidua serotina. I will now demonstrate it. In animals as well as in woman, there takes place upon the internal surface of the uterus, where the ovum is developed, an abundant proliferation of con- nective tissue, the elements of which not only be- THE HUMAN PLACENTA. 117 come more numerous, but each of them increases in volume. Between animals and the human species, however, there is this important difference: in the former, the hypertrophy and the hyperplasia of the sub-mucous connective tissue lift also the uterine mucous membrane, which is changed, as we have seen, into a glandular organ; while in woman, on the contrary, there is not only hypertrophy and hy- perplasia of the anatomical elements constituting the connective tissue, but those elements undergo trans- formation and give rise to the development of a tis- sue of special neutral cells, which are the stroma whence arises the glandular organ that constitutes the maternal portion of the placenta. Instead of the epithelial layer which represents the mucous mem- brane, the uterus where the placenta is formed in woman remains covered by the serotina. I owe to the kindness of our honored colleague, Dr. Belluzzi, the opportunity I have had to study the gravid uterus of a woman who died at the seventh month of pregnancy. Plate X., Fig. 3, represents a vertical section of the uterine surface of the placenta. At a, a, we see a layer of enormous fusiform cells, provided in part with short appendages. They show a hypertrophied and hyperplasic layer of cells of uterine connective tissue, of which we cannot say whether it belongs to the uterus, or is in process of transformation into the decidua serotina. It is cer- tain that when in delivery the placenta is detached, its separation from the uterus is effected normally in this very layer. On examining normal placenta after their expul- sion, and placing under the microscope the outer lay- 118 THE HUMAN PLACENTA. ers of the gray and jelly-like substance which covers their uterine surface, the very delicate cells which compose this layer are broken up, so that observing them thus, Robin was right in noticing their remark- able hypertrophy and their highly varied forms sim- ulating those supposed to be characteristic of cancer, especially since he submitted to microscopic exami- nation the pulp obtained by scraping. This process would necessarily detach thick round cells, with large nuclei, which form a second layer (Plate X., Fig. 3, 4, d), namely, the serotina. This part, whose cells are kept close together by interposed corpuscles of the connective tissue of the inferior layer I have described, presents the form of an elegant mosaic, on account of the rapid and re- markable metamorphoses which the cells of the sero- tina undergo. They are transformed into cells of fibrous tissue around the utero-placental vessels (Plate X., Fig. 3, 7), and pass through the same transforma- tion, in fulfilling their functions, as do real venous walls. About the venous sinuses which bear the blood from the placenta to the uterus (4), they are supported also against the villi of the chorion, and they have all around them a net-work of very deli- cate fibrous tissue which is the wall of the glandular organ ; for, in its internal part, we see developed the lacteal cells of the uterus (4). In favorable cuts from the base of the placenta we observe that, at the place where the villi are out- wardly covered by the cells of the serotina changed into fibrous tissue, they are continuous in the interior (that is to say, in the serotina itself) with the lacteal cells of the internal surface. In a word, the internal THE HUMAN PLACENTA. 119 surface of the cellular layer of the serotina is con- tinuous with the internal layer of the wall which surrounds the villi. At the base of the placenta the cells of the serotina are transformed into very apparent fibrous cells, and constitute quite a diaphanous fibrous tissue (c, e); in some places, as is represented in the illustration, may still be seen embedded the large round cells of the serotina. We also clearly perceive in the same fig- ure, that the cells of the serotina (4, d) are changed into fibrous tissue and cover the villi with fibrous cells. If higher up, in the external membrane of the villi, we no longer distinguish the fibrous elements, on account of its great transparency, nevertheless they are plainly seen at the place indicated, which is a continuation of the membrane which covers the villi in their smallest ramifications. The cellular or fun- damental elements of the glandular organ thus line the whole internal surface of the fibrous envelope which the serotina furnishes to the villi (Plate X., ie: 2,0, db). The villi increasing in size and multiplying their subdivisions, and the volume of the placenta aug- menting at the same time, the vascular loops which are formed push forward the primitive wall of the vascular branch or primordial villus, and we have the external wall which completely surrounds the villi. In this manner the glandular organ covers and envel- ops the subdivisions of the villi throughout their whole extent. On approaching the chorion, the wall of the glandu- lar organ which the serotina furnishes to the villi un- dergoes other modifications, Formerly granular, the 120 THE HUMAN PLACENTA. internal cells become transparent; their form, which was oval, is rounded; and they fill the whole inter- nal cavity of the glandular tube containing the ves- sels (Plate X., Fig. 1,d). Closely crowded together and in contact with the chorion, they are transformed into fibrous cells which, like large, tendinous cords, firmly fix the vessels to the chorion (e, e). This ex- plains why anatomists thought that the chorion fur- nished a membrane to the vessels. Others seem to have been also in the right when they said that the serotina dipped down into the interior of the pla- centa, and that the cellular structure, indicated as its uterine surface (Plate X., Fig. 3, 0, 8), appears still unaltered upon the internal surface of the chorion which adheres to the foetal surface of the placenta (Plate Xe Ried). | The modifications that I have always observed near the chorion in the internal cells of the glandu- lar organ in its normal state (Plate X., Fig. 1, d), I have also seen in some pathological cases toward the base or uterine surface of the placenta. The large, quasi-epithelial cells which fill the internal cavity of the villi proliferate near the chorion in so remarkable a manner over the whole extent of the villi, that they prevent the blood from circulating to such a degree that some vessels are seen almost obliterated, while others have even disappeared. By studying microscopically a placenta thus dis- eased, it is «seen composed of tubes closely pressed together, whose walls are formed by the increased development of the glandular structure about the vascular villi, which are in great measure atrophied by the enormous proliferation of the cells which has THE HUMAN PLACENTA. 121 been carried on in the internal wall of the glandular organ. The enlargement of the tubes is, in some places, so great that their exterior walls touch each other, and they leave in the utero-placental sinuses no space for the blood of the mother. I speak of this single pathological lesion of the pla- centa, because it satisfactorily confirms the normal structure of the placental villi in the human species ; and I point out thus the capital distinction between the human placenta and that of animals. Among the latter, we have seen that it is always a transformation of the uterine mucous membrane which gives rise to the development of the glandular organ or maternal portion of the placenta, without any departure from the ordinary typical forms of the most simple gland- ular organs. In the former, on the contrary, it is not a transformation or a perfecting of preéxisting parts, but the neoformation of a very special tissue, that of the serotina, which, if it has their fundamental char- acters, is yet widely removed from the typical forms of glandular organs in animals. From these facts follows another which further con- stitutes a distinction between the human placenta and that of animals. In the latter, the glandular organ originates from a transformation and expansion of the preéxisting mucous membrane, with hypertrophy and hyperplasia of the connective tissue and of the sub-mucous ves- sels ; it follows that the villi of the placenta are al- ways separated from each other by the walls of the follicle which receives it, and by the hypertrophied connective tissue interposed between the follicles, in the midst of which course the vessels that serve for 122 THE HUMAN PLACENTA. nutrition. Consequently, in animals, the villi of the foetal placenta are only and exclusively in direct con- tact with the fluid secreted by the glandular organ; in the human species, it has been in all times more or less well established that the villi of the foetal pla- centa float in the maternal blood. What I have just explained, upon the anatomical structure of the villi, must necessarily modify the general idea that has been formed with regard to them. In fact, the maternal blood directly bathes the external wall of the glandular organ furnished to the villi by the serotina. How is this accomplished ? In Plate X., Fig. 1, 9, 9, g, 1 have represented. the large cavities or lacune to be met with upon the in- ternal portion of the uterine surface of the placenta, as well as throughout its whole thickness, even to the surface of the chorion, which, full of blood, as in the figure, and united with each other by intercommuni cations, constitute the cavities or placental sinuses, in which swim the villi entirely surrounded by the glandular organ. Very different views are held by anatomists as to the manner in which the utero-placental vessels anas- tomose with each other to form these venous sinuses in the placenta. ! I have specified the large and numerous cavities which are easily seen in the internal parts of the hu- man placenta, in order to demonstrate that the exter- nal walls of the glandular organ, which surround all the villi, are continually bathed by the maternal blood. But this same observation leads me to believe that the utero-placental arteries empty directly into the lacune of the placenta as I shall presently explain. i THE HUMAN PLACENTA. 123 I have not, however, yet been able to collect positive evidence sufficient to satisfy me in what portion of the placenta this takes place, and how the arteries act at the places where they open. My present pur- pose is to establish the fact that in the human pla- centa the vessels act quite differently from what we observe in animals. For with them, the external walls of the glandular organ are never bathed di- rectly by the blood of the mother, and the utero-pla- cental vessels are easily distinguished at all points of the connective tissue in the placental sections (Plate VIIL, Figs. 1 and 2, 9, 9). The most illustrious anatomists, falling to grasp the fundamental difference which exists between the hu- man placenta and that of animals, and having often made use of that of the latter to explain that of the former, have necessarily fallen into contradictions and errors which have been the cause of no slight confu- sion. This severe judgment upon such respectable observers will be pardoned me if I repeat the precise words of the celebrated Bischoff : — “Hunter taught that in the same way as the de- cidua covers the remainder of the surface of the ovum, it covers it also as reflected decidua at the point where the placenta is formed; but that in the course of time it attains a considerable development at that point, and it there forms numerous cavities with very thin walls, into which the villi of the foetal part of the placenta insinuate themselves. He added that the uterine arteries and veins open into those small cells or cavities without branching or at most ramifying very little. The cavities are therefore always full of blood brought on one hand by the 124 THE HUMAN PLACENTA. arteries, and taken away on the other by the veins. The later researches of Weber accord with those of Hunter upon essential points, with this one difference, that what the English anatomist calls cells of the decidua, Weber styles origin of the veins or venous sinuses. Consequently, while in the other parts. of the body the arteries are divided into branches more and more slender, in order to be continuous, through the medium of the capillary net-work, with the equally minute roots of the veins; in the placenta, according to Weber, the uterine arteries are continuous, with- out furnishing any arborescent ramifications, with the sufficiently ample origins of the veins, which, anasto- mosing with each other frequently and at all points, appear to form thus a system of small cavities, to which the blood passes through venous trunks from the uterine arteries. The walls of the veins are ex- tremely thin in the placenta; they are reduced to the single internal tunic, and when they do not con- tain blood, they contract, so as to become almost in- visible. The villi of the chorion, constituting the foetal placenta, which are divided into extremely mi- nute ramifications, penetrate into the venous sinuses, where the delicate coating of the veins furnishes them with an envelope in the form of a sheath; so that they are always bathed by the maternal blood. Now, as the blood of the foetus travels a long and quite sinuous passage through the villi, the two bloods find frequent opportunities for a reciprocal exchange of materials.” This description of Weber’s, reproduced by Bischoff, has been pretty generally admitted in modern times. It agrees with the observations of Blokham, Knok,' 1 London Gazette. 1840. - THE HUMAN PLACENTA. 125 Reid, and Coste. But the researches of Eschricht raised doubts with regard to it. Basing his observations upon the placental structure of mammals, in which the two bloods of the mother and of the foetus seem always to be conducted towards each other by capil- lary vessels, he concluded that in the human species, also, two net-works of capillary vessels continually come in contact, and that the uterine arteries are con- tinuous with the uterine veins by means of a capillary net-work as tenuous as that which exists between the umbilical arteries and veins. He believed that prolongations of the decidua in the form of folds pen- etrate, in the interior of the placenta, between the ramifications of the chorion, and clothe them with a somewhat delicate membrane which serves as a sup- port to the capillary net-work placed between the uterine arteries and veins. This net-work has been imagined, it has not been seen, and the doctrine of Eschricht found no parti- sans; even a superficial inspection of the human pla- centa shows in its interior the large sinuses full of blood, in the midst of which float the villi. Hence Bischoff, as I have just said, attempted to reconcile the doctrines of Hunter and of Weber, and he was right. As for myself, it is sufficient, for the present, to have established that these illustrious men have been forced to admit, for the maternal vessels of the placenta, a different termination from the normal and ordinary one. Notwithstanding my strong desire to form a clear and precise idea of the doctrine of Weber upon the circulation of the maternal blood in the placenta, I must frankly confess that I have never been able to 126 THE HUMAN PLACENTA. succeed in comprehending how it could be that the villi of the foetal placenta were bathed by the blood of the venous sinuses, since, in admitting, with the illustrious author, as thin a wall as one can imagine, in the dilated placental veins, one cannot be per- suaded that the villi traverse it, and thus put them- selves in contact with their blood.’ If the author meant that the very delicate venous walls are folded over the villi, enveloping them with a sort of sheath, the walls of the vessels of the foetal villi would then necessarily be no longer in direct contact with the maternal blood, but rather with the wall of the vessel that contains them, and the cells and lacune which are quite distinctly seen could not be formed. The researches that I have often repeated in order to follow the utero-placental vessels, venous as well as arterial, beyond the membrana serotina, have been unsuccessful, though the diameter of both is quite re- markable and renders them consequently very easily perceptible in that membrane (Plate X., Fig. 3, 4, è). I am therefore disposed, as I have said before, to con- sider as correct the opinion of Farre, that the utero- placental arteries open directly into the sinuses of the placenta. But this subject deserves, in my opinion, 1 J have the good fortune to possess the memoir of Weber, ‘‘ Zusatze zur Lehre vom Baue und Verrichtungen der Geschlechtsorgane. Leipzig, 1846,’’ which belonged to Eschricht, and I find the following words in it underlined with a pencil, counter-marked besides by an exclamation point: ‘In diese Mutterblute fiihrenden Canale insinuiren sich die zar- ten, gefassreichen, von Embryoblute durchstromtens Zotten des Kindes- theils der Placenta, sie hangen daher in diese Canale hinein und werden vom vorbeistromenden Mutterblute umspult.’? The doubts of Eschricht confirmed my own, without convincing me, however, of the existence of the very fine anastomoses he had imagined. THE HUMAN PLACENTA. 127 to be better studied and more fully explained. For if these arteries open upon the internal surface of the serotina, where the orifices of the large utero- placental veins also exist, there would follow an out- pouring of blood into the large cavities or lacuna of the placenta, and there must be a continual mingling of the arterial blood of the mother with that which would have become venous. I believe this is what really does take place; and I hope I shall not lack the opportunity of demonstrat- ing it, when completing the observations which in the present work I have only alluded to. By this fact, the placental respiration would be explained in a sim- ple and clear manner, and we could also account for another observation made by certain anatomists, that in the process of injecting the human gravid uterus, the coloring matters pass easily enough, if we operate from the foetus to the mother; but this is not true, if we inject from the mother to the foetus. In the first case, by lacerating any one of the villi, the coloring matter which pours out into the placental sinuses communicating with each other, and which from there insinuates itself with ease also into the large orifices of the arteries and of the utero-placental veins, thus passes without obstacle into the uterus. I know no other example of lacunar circulation in | any organ of the superior animals; and it appears to me that this of the human placenta signally deserves the attention of observers. The existence of the utero-placental vessels, though formerly denied, is at present called in question by no one. Some doubt may still remain as to their genesis or mode of formation; and I do not pretend to re- 128 THE HUMAN PLACENTA. solve such a question peremptorily. I will only add | that, in the study of the uterine mucous membrane of a dog almost at term, I was agreeably surprised to find areally splendid example for demonstrating the rich and abundant genesis of new vessels, by the vas- cular transformation of corpuscles of connective tis- sue. Itisa phenomenon that one observes at the first glance, and which I have represented in Plate II, Fig. 1, d, d. The demonstration of the genesis of new vessels, by the method I have just indicated, not only serves to make these vessels understood, but is also usefully applied to several other questions of normal or pathological anatomy, and it furnishes a new and important argument to those who, like my- self, believe that the corpuscles of the connective tis- sue are provided with a special wall. At all events, the facility, on the one hand, with which we recognize, in vertical sections of the decidua serotina, the transverse cuts of the utero-placental arteries (Plate X., Fig. 3,2) and the large apertures of the veins (4), and their total absence in the por- tions of the serotina which become blended with the cells of which the chorion is composed (Plate X., Fig. 1, 7,7); and, on the other hand, the easy demonstra- tion of the large sinuses full of blood in the interior of the placenta, in which float the villi (Plate X., Fig. 1, 9,g); the impossibility that has always existed of demonstrating the capillary net-work of the utero- placental vessels in the placenta; the affirmations of Farre, and the numerous facts I have just stated, all lead to the conviction that the lacunar circulation, of which I have before spoken, is carried on in the pla- centa. THE HUMAN PLACENTA. 129 I do not pretend to have touched, even slightly, on all the very important questions which rise from the observations I have set forth. My aim has been to establish one single fact, namely, that the maternal portion of the placenta in the mammalia, and in the human species, has always a glandular structure. In the following chapter I shall sum up and arrange the statements deduced from this fact. 9 CHAPTER VII. I. “CONCLUSIONS RELATIVE TO THE UTRICULAR GLANDS AND THE MUCOUS MEMBRANE OF THE UTERUS. THE uterine mucous membrane in woman and in certain animals, as the mare for example, is repre- sented by simple epithelial layers. Small and narrow introflexions of the epithelial layer in some animals, in others, elevations of the sub-epithelial connective tissue, with numerous inflexions which form the folds of mucous membrane on the internal surface of the uterus, are not sufficient to establish real differences between the uterine mucous membrane of mammals and that of woman, still less to lead to the belief held by some illustrious anatomists, that the uterus of woman has no real mucous membrane. The utricular glands of the uterus are usually very numerous, and open into the epithelial layer of the mucous membrane, whether that membrane shows itself totally inseparable from the uterine tissue, or whether it is lifted up as a special membrane and dis- posed in more or less prominent, simple, or highly festooned folds. The great folds of the uterine mucous membrane, with their many festooned depressions, represent enormous glandular follicles which may stand for utricular glands. This fact is oftener remarked in MUCOUS MEMBRANE OF THE UTERUS. Lol certain animals in which the uterine glands are lack- ing. Some able anatomists have failed to observe them in the uterus of the rat, and Iam convinced that they do not exist in that of the rabbit. The absence of the utricular glands in the uterus of certain ani- mals with a single placenta is a fact of no slight im- portance, for it invalidates in some degree the asser- tion of those who claim that these glands play an important part in the formation of the placenta in the above-named animals. In those animals in which the uterine glands have been studied with attention, quite remarkable differ- ences are noted, in relation both to their form and to the kind of epithelium which lines their cavity. Since the observations of Sharpey and Weber, it has been admitted as a demonstrated fact in science that in the uterus of some animals, such as the cat and the dog, there exist two species of uterine glands, which, on account of their form and volume, have been named simple and branching.’ Moreover, small and not important differences are noticed in the utricular glands of the uterus in all animals and even in the human species. Hence the error of the anatomists and physiologists who claim that there are two species of glands with a double and widely dif- fering function, namely: the secretion of the uterine mucus for the simple glands, and a participation in the formation of the placenta for the branching ones. I have, however, observed two really distinct spe- cies of uterine glands in the cow and the sheep: the 1 Thave been unable to demonstrate that there are two varieties of these glands in the dog, and I have shown that in the cat there is only one species of glands, although they may vary greatly in volume. 132 MUCOUS MEMBRANE OF THE UTERUS. utricular or branching, of slightly variable volume, but always highly developed, and the simple glands, always extremely small, proceeding from very nar- row and sinuous inflexions of the epithelial surface of the mucous membrane. Moreover, these minute, slightly developed glands, which, to distinguish them from the others, I have called glandular follicles, pre- sent, on comparison with each other, marked differ- ences as to length and breadth. They are scattered over the whole internal surface of the uterus, and are constantly agglomerated in the places corresponding to the cotyledons, which, in the non-gravid uterus, appear covered with a thin, smooth, and compact layer of epithelium; this represents the most simple form of the uterine mucous membrane, as in woman. In the rabbit, instead of utricular glands, we find over the whole surface of the uterine mucous mem- brane numerous and very short glandular follicles, which are only inflexions of the epithelial layer, rep- resenting also, in that animal, the mucous membrane of the uterus. In this case the only difference is that the internal surface of the mucous membrane does not appear glossy and smooth as in woman. In all animals in which the uterine utricular glands exist, as well as in the human species, they increase in volume during pregnancy. The glandular follicles also augment in size during the gestation of the cow. The development of the glandular follicles in the gravid uterus of the rabbit is still more remarkable, and it has a much greater importance and significance. At the places where the ova are arrested after their fecundation, the follicles augment in volume and are transformed into a glandular organ or the maternal MUCOUS MEMBRANE OF THE UTERUS. 138 portion of the placenta. In the empty portions of the uterine horns the growth of the follicles causes the elevation of the mucous membrane under the form of peculiar folds; they seem destined to per- form, during pregnancy, the functions of the utricular glands, which are lacking in those animals. In cases where the placenta is villous or diffused, as in the mare, all the utricular glands, even after the glandular organ or uterine portion of the placenta is formed, empty the fluid which they elaborate directly into the space comprised between the chorion and the uterus. The uterine surface of the chorion of these animals is covered with an epithelial layer which clothes also the base of the tufts of its villi, and is continuous with the epithelium that covers them. The outer epithelial layer of the chorion may represent the uterine decidua in the mare. When the placenta is multiple, as in the ruminants, and especially in the cow, the uterine utricular glands, which do not correspond to the cotyledons, likewise pour their fluid between the chorion and the uterus. The epithelial layer which forms the decidua of the cow is a little more remarkable than in the mare. The utricular glands which exist in the so-called rudi- mentary cotyledons of the non-gravid uterus, as well as the glandular follicles agglomerated in those parts of the organ, probably open into the bottom of the cup-shaped elevations which constitute the new-formed glandular portion of the cotyledons of the gravid uterus. The small number of utricular glands at that point, the delicacy of the mucous follicles, and, still more, the increased attenuation of the walls of the glands, the transparency and the metamorphosis Cc eee n 134 MUCOUS MEMBRANE OF THE UTERUS. of their internal epithelium, never allowed me to see the precise point where they open in the interior of the glandular organ. The glands and the follicles, which are clearly seen in transverse sections of the peduncle of the cotyledon, are badly and imperfectly distinguished in vertical sections, and they become less and less marked the nearer we come to the sur- face of the peduncle where the glandular organ is formed. If the placenta is single, and if there exist utric- ular glands, as in the carnivora, those which corre- spond to the place where the placenta is developed open into the lower part or culs-de-sac of the glandular follicles of new formation, which are nothing but fes- tooned folds of the uterine mucous membrane trans- formed into a glandular organ. In the rest of the uterus, even in these animals, the utricular glands pour the secreted fluid between the uterus and the chorion. | The uterine decidua of woman, as well as the so- called catamenial decidue, is a product of materials elaborated by the utricular glands. Consequently, the decidua cannot be considered as a swelling of the. uterine mucous membrane, and still less as resulting from the extremities of the glands, from the connect- ive tissue, and from the vessels that surround them, as Weber and Bischoff have stated. The numerous openings or holes, which give the appearance of a sieve to the uterine decidua of the human species, only indicate the points corresponding to the orifices of the utricular glands in the cavity of the uterus which remain fully open to allow the constant pas- sage of the product of their secretion. MUCOUS MEMBRANE OF THE UTERUS. 135 The uterine decidua may be demonstrated also in the cow, though several authors have denied its ex- istence, on account of its attenuation. It has the same origin as the human decidua, but because in the cow, besides being thin, it is attached to the chorion and not to the uterus, as in woman, we do not ob- serve in it the numerous openings that are seen in the latter. In the vaccine decidua, instead of holes, there is a thickening of some of the elements which are secreted by the glands at the points correspond- ing to their orifices, which infiltrates as far as the chorion. Burkardt gave them the name of chorial squamule. These opposite conditions confirm the fun- damental fact concerning the origin and structure of the uterine decidua. In no species of animals, whatever the form of the placenta, do the villi of the chorion penetrate into the utricular glands of the uterus, as some anatomists have taught. The constant increase in volume of the utricular glands during pregnancy, in animals as well as in the human species, proves beyond doubt that they have an important function to fulfill for the life of the foetus. For the present, it appears to me reasonable to suppose that their principal function is that of furnishing materials for its nutrition, before the de- velopment of the new glandular organ which consti- tutes the maternal portion of the placenta in all mam- mals and in the human species. Although the fluid secreted by the utricular glands does not always min- gle directly with that which is elaborated by the ma- ternal placenta, as in the carnivora, the undeniable observation of this fact in some animals leads us 136 MUCOUS MEMBRANE OF THE UTERUS. reasonably to suppose that an important nutritive element is furnished by these glands for the nutrition and growth of the foetus. This seems more probable still, if we think of the very great number of these glands, of their constant increase in volume during pregnancy, and of the remarkable quantity of fluid they secrete in some animals, as in the mare, between the chorion and the uterus; and finally, if we take into account the fact that the whole uterine mucous membrane augments in volume during gestation, and multiplies its excavations or festoons, which exhibit enormous follicles in those animals in which the true utricular glands are wanting. MATERNAL PORTION OF PLACENTA. 137 II. CONCLUSIONS UPON THE GLANDULAR ORGAN OF NEO- FORMATION OR MATERNAL PORTION OF THE PLA- CENTA, IN THE MAMMALIA AND IN THE HUMAN SPE- CIES. In the uterus of all mammals, woman included, there is formed during pregnancy a new glandular organ, into the internal cavities of which the villi of the chorion always penetrate. The placenta is, therefore, formed of two parts, en- tirely distinct both in structure and in function: the foetal portion, which is vascular or absorbent, and the maternal portion, which is glandular or secretory. The blood of the mother always furnishes the ele- ments for the formation and secretion of the new glandular organ or maternal placenta. In no case do the maternal vessels cross each other and come in contact with those of the foetus; or, in other words, the parts constituting the foetal placenta are always in contact with the fluid elaborated by the new gland- ular organ, and are bathed by it. The doctrine, universally admitted by physiologists, of the foetal nutrition by means of an exchange of materials through the processes of endosmose and ex- osmose between the vessels of the mother and those of the foetus fails in the presence of actual observa- tion. In the same manner as in the first periods of extra-uterine life the child is nourished by the mater- nal milk absorbed by the intestinal villi, so during intra-uterine life the foetus finds its nourishment in 138 MATERNAL PORTION OF PLACENTA. the fluid or milk secreted by the glandular organ and absorbed by the villi of the chorion. Anatomical re- searches have led to the discovery of the simple fact. Physiology and chemistry will make known the se- crets of function. The new glandular organ or maternal portion of the placenta is developed at different periods of preg- nancy in different species of animals. In case the placenta is diffused, as in the solipeds, it appears over the whole internal surface of the uterus. When the placenta is multiple, it develops at certain circum- scribed points, as in the ruminants. Finally, it forms at the place where the ovum is arrested, when the placenta is single, as in the rodents, the carnivora, and the human species. The growth of the new glandu- lar organ is modified, according to the various forms of the placenta; but in animals it does not differ from the simplest types of glandular organs in adult indi- viduals. In short, in animals the maternal placenta always preserves the character of an open glandular follicle. The typical form of the simplest glandular follicle is, however, wanting in the human species. The anatomical cause of the differences between animals and the human species lies in the fact that, in animals, the new glandular organ, or maternal pla- centa, results from a modification and transformation of the preéxisting mucous membrane of the uterus ; while in woman the same portion of the placenta is formed by a stroma, which stroma is itself of new development, and is elaborated from the connective tissue of the internal surface of the uterus. This stroma is known by anatomists under the name of decidua serotina. MATERNAL PORTION OF PLACENTA. 139 The fundamental type of this new glandular organ is that of single follicles crowded close together and lining the whole internal uterine surface, as we see in animals with a disseminated placenta, and as I have demonstrated in the uterus of the mare at term. In animals with a multiple placenta, such as the rumi- nants, and particularly in the cow, as I have shown, a clear distinction has not hitherto been made be- tween the permanent part of the uterine cotyledons and the glandular portion of new formation (that is to say, the caducous or perishable part, which disap- pears after delivery), which is developed upon the cotyledons only during gestation. The persistent portions, which are observed even in the foetus, and which are called rudimentary cotyledons, simply indi- cate the places where, during pregnancy, the maternal or glandular portions of the placenta will be devel- oped. In the cow, the new glandular portion of the cot- yledon preserves the form of an aggregation of sim- ple, open follicles.. But if we compare them with the cotyledons of the mare, we find the only differ- ence to be their manner of union and position in the uterus. In the cow they are not simply glandular follicles lying near together, but they are super- imposed upon each other, and they are not found over the whole uterine surface, but only upon the portions of the non-gravid uterus called uterine cot- yledons. They are not vertical, like the former, but parallel to the line formed by the uterine surface. Neither do they open separately, nor directly into the cavity of the uterus, but indirectly by means of one large aperture corresponding to an internal cav- 140 MATERNAL PORTION OF PLACENTA. ity, into which many follicles empty themselves in common. It still remains to be known how and by what his- togenetic process the new and glandular part of the cotyledons is developed, and at what period of preg- nancy the glandular follicles are formed in the gravid uterus of the solipeds. Observations made upon the carnivora, which I shall presently describe, lead us to take these processes for granted, as they also allow us to infer the manner in which the new glandular portion is destroyed after delivery, in the mare as well as in the cow. But an exposition of the facts, when ascertained, will be better than conjecture, how- ever probable. In animals with a single placenta, such as the rodents and the carnivora, the glandular organ is strikingly modified by the forms which it assumes, without losing those characteristics which belong to the fundamental and simple type of a follicle. The changes which it undergoes relate only to the length and to the extremely sinuous course of the glandular follicles, and to the multiple communications which they have with each other. But the closed extrem- ity of the separate follicles of the uterine face of the placenta, and their orifices towards its foetal surface, are always easily observed. In all cases the chorial villi of the foetal placenta penetrate through orifices into the interior of the follicles; only, when the pla- centa is single, the chorion adheres to its foetal sur- Mace. The modifications I have pointed out in the new glandular organ of the uterus of mammals, according to the various forms of the placenta, recall and dem- MATERNAL PORTION OF PLACENTA. 141 onstrate, in a higher degree of development, the dif- ferences described in the mucous membrane of the non-gravid uterus. The slight and narrow depres- sions that are met with in the mucous epithelium of some animals are reproduced on a large scale by the structure and disposition of the maternal placenta in the solipeds. In like manner, the fold-like elevations of the mucous membrane, with numerous and broad lateral sinuses, which we have remarked in other ani- mals, are represented, under a more complex form, by the glandular portion of the cotyledons in the gravid cow. On the other hand, the long and sinuous follicles of the maternal or glandular portion of the single placenta in certain animals show only a re- markable augmentation of the follicles and depres- sions preéxisting in the uterine mucous membrane of other animals. The maternal portion of the placenta remains in- tact in the uterus during delivery, and is then de- stroyed gradually, in cases where the placenta is disseminated or multiple. In the mare there remains | no trace of it on the internal surface of the non- gravid uterus. In the cow it is preéxistent at preg- nancy; after delivery, we find the traces of the points where the new glandular organ was formed, and where it will be formed again in successive pregnancies. The trace of these places is known under the name of rudimentary cotyledons, even in the uterus of the foetus. In case the placenta is single, the portion of the uterus which was occupied by the placenta remains, after delivery, covered by a thickened mucous mem- brane, surrounded on the sides by very elevated folds. 142 MATERNAL PORTION OF PLACENTA. This thickened mucous membrane, quite wide and somewhat rough a few hours after delivery, appears three days later lifted into several closely-crowded folds. These changes should be attributed to the return of the uterus to its normal state. In delivery, only that portion of the elevations of the mucous membrane is detached which had been transformed in order to constitute the new glandular organ or maternal placenta. The portion of the mucous mem- brane remaining in the uterus, and whose changes I have described, is itself gradually and entirely de- stroyed by fatty degeneration. Thirty days after parturition I found it had completely disappear from the uterus of a dog. In the human species cays is there a total separa- tion and expulsion of the glandular organ in delivery. Consequently, in woman alone does there take place an extensive traumatic lesion of the uterus, on ac- count of the laceration of the parts, which leaves bare the uterine tissue over all that portion which had been covered by the placenta. In animals with a single placenta this lesion is limited to the connective tissue of the folds of the mucous membrane which has accompanied the elevation and the growth of the follicles of new formation. The uterine contractions, the drawing together of the parts by the diminution in volume of the uterus, bring prompt and efficacious relief to this lesion. There is an additional anatomical explanation, from these facts, of the sentence addressed to woman: “In sorrow thou shalt bring forth chil- dren.” Important differences are observed in the maternal placenta of the human species which remove it from MATERNAL PORTION OF PLACENTA. 143 the type common to animals. In woman it is not the uterine mucous membrane that is perfected, as in ani. mals, in order to form the glandular organ, but it arises from the neoformation of a layer made up of large cells furnished by the sub-mucous connective tissue of the uterus, and known by anatomists under the name of decidua serotina. . The large, neutral cells of the serotina are the stroma whence the maternal or glandular portion of the placenta takes its origin. The fundamental and typical parts of the glandular tissues are met with in the maternal portion of the placenta in woman. All the accessory characteristics, that is to say, those which relate to the form of a sim- ple glandular follicle, disappear altogether. The cellular structure of the serotina which lines the uterine face of the placenta is also observed with ease upon its foetal surface covered by the chorion, where the cells of the serotina are blended with the connective tissue. It is, therefore, demonstrated in a clear way, that the serotina penetrates into the in- terior of the placenta. There the cells of the serotina are transformed at different points into true fibrous tissue, more especially to circumscribe the large lacu- ne of the placenta which contain the maternal blood. The same transformation takes place in the substance of the serotina, to furnish a solid wall to the utero- placental veins before they reach the uterus. Fur- ther, the serotina clothes the villi of the chorion throughout their whole extent and in their numerous ramifications to the interior of the placenta. Every- where the cells of the serotina offer examples of the greatest and most rapid modifications. The most im- portant consists in the sheath which the serotina fur- 144 MATERNAL PORTION OF PLACENTA. nishes to the villi of the foetal placenta as far as the chorion. This sheath is formed on the exterior by a fibrous membrane, and by an internal epithelial layer, which together constitute the fundamental parts of the glandular organs. Near the chorion, the decidua serotina is trans- formed by degrees into fibrous tissue, and forms strong cords which serve to fix firmly the vascular trunks, whence depart the chorial villi. I have observed that this same thing had taken place, in an abnormal man- ner, in a morbid placenta, which produced the death of the foetus and caused abortion. When once the vascular trunks of the foetal pla- centa are enveloped by the serotina, transformed into a secreting glandular organ, the numerous villi that depart from it push before them, while increasing in volume, the walls of the sheath, and they are them- selves thus completely clothed with it, like the fingers of a hand ina glove. In this way the blood of the mother bathes directly the exterior wall of the sheath furnished by the serotina to the villi. In the human species only the utero-placental arteries and veins are not divided into trunks and branches in the placenta. ‘The maternal blood is poured out, in the interior of the placenta, into large cavities, lacune, or sinuses, which communicate with each other, and are circumscribed by the chorion on the foetal side and by the serotina on the uterine side. The cavities cireumscribed by the decidua serotina, transformed, at those points, into fibrous tissue, are in great measure filled by the blood and by the volu- minous tufts of the chorial villi that are covered by the serotina, changed into a glandular organ. MATERNAL PORTION OF PLACENTA. 145 The intimate union of the vessels with the chorion and the serotina, the internal prolongations of the latter, which are mingled with those of the chorion, limit the distention of the internal cavities or pla- cental lacune, — a distention which would necessarily be produced by the arterial blood which constantly comes from the mother to the placenta. This blood, which is poured into these lacun®, is mingled with that which has already become venous in the interior of the organ. The great cavities or venous sinuses, circumscribed by the serotina, carry back to the mother the blood which has fulfilled its office in the placenta by means of the utero-placental veins. In the human placenta, also, the vessels which bring the maternal blood never come in contact with those which belong to the foetus. So it is only in the human species that a mixed blood, arterial and venous, is brought in contact with the external face of the glandular organ which con- tains the vessels of the foetus; and this by a mode of lacunose circulation, of which, to the present day, no example has been met with in the superior ani- mals. It is in the human species alone that a mixed blood of the mother herself is brought back from the pla- centa into the general circulation. 10 APPENDIX. IL ON THE FORMATION OF THE MATERNAL OR GLANDU- LAR PORTION OF THE PLACENTA IN THE HUMAN SPECIES AND IN CERTAIN ANIMALS. Wuen Professor Bruch and my old friend Andreini proposed to me to publish my memoir upon the pla- centa in French, I had at first the idea of revising it, at least in part; for new researches and later ob- servations had shown me that it needed to be some- what modified, or to have some additions made to it. I afterwards decided to have it followed by an ap- pendix, in which are to be found the new observa- tions and the modifications resulting from them. Young persons who devote themselves to the study of the natural sciences may thus be convinced that the investigation of facts is not an easy thing, as oO? many seem to think, but that it is, on the contrary, 1 This Appendix, written for the French edition, was thoroughly re- vised and published in the Transactions of the Academy of Sciences of the Bologna Institute, second series, vol. ix., and illustrated by six plates. At first I thought to present it in place of the Appendix to the English reader. However, decision was made to retain the Appendix, and publish entire the professor’s more recent monograph on the Unity of the Anatomical Type of the Placenta in Mammals and in the Human Species, and on the Physiological Unity of the Nutrition of the Foetus in all the Vertebrates, published in the Transactions of the Institute, 1877.— H. O. M. 148 APPENDIX. always long and often laborious. For that very rea- son it is generally fruitful in valuable results. While truthfully presenting observations, one may sometimes be mistaken in the manner of interpreting them; however, the fact remains entire in its truth, and sooner or later it becomes useful to science. For example, in having drawings made of the large excavations in Plate IX., d, d, I regarded them as culs-de-sac of large folds of the uterine mucous mem- brane, upon which the maternal placenta of the dog had been formed. It was an error. Later observa- tions have proved to me incontestably that these large cavities are produced by a degeneration and special dilatation of the subjacent utricular glands at the place where the placenta is developed. The fact remains; its interpretation only is modified. In order to appreciate it fully, one must have followed it from its discovery to its development. It is thus that we teach ourselves and others, and throw light upon science, which is pure and simple truth. I hope, then, that not only for young students, but for all others likewise, it will be of great service to follow conscientious observers in the path which con- ducts them from error to truth, and I trust at least that my purpose will not be criticised. In my memoir I have scarcely touched upon the investigation into and the description of the histo- genetic process and the successive transformations of the primordial elements constituting the glandular organ, or maternal portion of the placenta. Such a research is pursued with disadvantage, on APPENDIX. 149 account of the difficulty one is under of procuring gravid animals at different periods of gestation. It is, however, of the greatest interest; for it is only by the exact and precise knowledge of those successive changes that a clear and certain proof of the neo- formation is deduced, and that the opinion can be re- futed of those who, not having had the opportunity of repeating minute and long-continued observations, think that the glandular organ is only an expansion, or a simple transformation, of preéxisting uterine parts, as has been said of the utricular glands. I shall therefore summarily describe in this Ap- pendix the results of my studies made after the pub- lication of the memoir. I shall limit myself to those which suffice to prove that, during pregnancy, there takes places a true glandular neoformation, and that, moreover, the glandular organ in its mode of develop- ment wholly departs from the ordinary and known laws which regulate the formation of glands in the animal organism. The permanence of the glands in beings that are organized and destined to live, and the necessarily temporary existence of the glandular organ of the placenta, reveal the purpose, if not the explanation, for the diversity of the laws which, in each case, di- rect their formation. Histologists agree in saying that all glands develop by means of an introflexion of an epithelial layer, and that the differences to be observed among them are only more or less remarkable modifications of this primitive and constant fact. In the formation of the maternal placenta, the glandular organ, though it be- gins in different ways in the different species of ani- ne APPENDIX. mals, is never formed by an introflexion of the uterine epithelium and of the sub-epithelial connective tis- sue. It is constantly the result of a production of histological elements unlike those that existed, and their successive changes constitute the glandular por- tion of the placenta. The placenta is destined to be loosened and expelled from the uterus in parturition, or slowly to degenerate and afterwards disappear, ac- cording as the maternal portion remains entirely at- tached to the uterus, as in the cow, or only partially so, as in the dog. I shall del describe these modes of placental formation in the cow, among the ruminants; in the cat, among the carnivora; and inwoman. I shall add to this the observations upon certain peculiarities of placental structure in animals that I had not before been able to examine. I. ON THE FORMATION OF THE MATERNAL PLACENTA IN THE COW, AND OF THE PLACENTA OF THE SHEEP, THE MOLE, AND THE HIND, SECTION I. THE COW. Amone the ruminants, the animal which has offered me the greatest facilities in my researches is the cow. The public abattoir has furnished me all the uteri of those animals killed in a condition of preg- nancy; and, notwithstanding the agricultural regu- lations of our country, which are opposed to their APPENDIX. 151 being thus slaughtered, I have been able to obtain two, of which the foetuses were found at that degree of development usually assigned to between the fif- tieth and fifty-fourth days of gestation. At this period of pregnancy, the glandular organ, though small, is already completely formed in the middle part of the full uterine horn. Below, and still better towards the extremity of the horn, smaller cotyledons are seen at different degrees of development, which are very well adapted to the study of the various phases of the neoformation of the glandular part of the placenta, that is to say, of the uterine cotyledon. To be brief, I shall review the facts that I have ob- served; and, to make them as clear as possible, I shall present, at the different periods of evolution, the most remarkable changes that I have noted, from the most simple or primordial to the formation of the large calices represented in Plate VI. First Perion. — We perceive only a slight tumefac- tion over the whole surface of the uterine cotyledons, —a surface which was level and smooth in the non- gravid uterus. According to the position of the uterus, the swollen surface of the cotyledons has the appearance of a soft crust, of a yellowish-white in some, and of a bright red in others. By the simple pressure of the uterine walls which touch the cotyle- dons, it is easy to make those which were yellowish turn red, and vice versa. This makes it certain that the different coloration of the cotyledons does not depend merely upon the fullness or emptiness of the blood-vessels; it proves also that the facility with 192 APPENDIX. which the two conditions are produced is connected with the extent of the vascular net-work which has been developed in the sub-epithelial connective tis- sue of the uterine surface of the cotyledons. If, for this experiment, we make use of a magnify- ing-glass, we easily distinguish this vascularization. We also see the large sinuosities of the more super- ficial new vessels, and we perceive that their convexi- ties are turned towards the uterine cavity. Consequently, if we examine with the microscope a vertical section of these cotyledons, it no longer appears even and smooth, as in the unimpregnated state, but everywhere slightly undulating. The first period of the neoformation would then be that of a vascular hyperplasia. This vascularization may be rapidly established, and in Plate IL, Fig. 1, d,d, I have already shown how it is produced in the uterus of the dog. The easy demonstration of the direct communica- tion of the corpuscles of connective tissue with the blood-vessels does not merely serve to explain the rapidity of the vascular neoformation, but it is also, I think, a beautiful method for illustrating the pas- sage of the white globules of the blood into the cor- puscles of the connective tissue. Cohnheim has, by his observations, forcibly called the attention of pathologists to this fact. Seconp PerIion. — At this stage of the neoforma- tion of the glandular organ, one may easily under- stand the sinuosity and the curvature assumed by the vessels of the sub-epithelial net-work of the cotyle- dons towards the internal cavity of the uterus. APPENDIX. 193 Tarn Perion. — Between this and the second pe- riod there is no essential distinction, but simply a dif- ference of volume or development in the vascular loops. They lose, in fact, the tenuity which they had on the old surface of the cotyledon, in order to form projections, rising and surrounding themselves with connective tissue, and becoming covered with a thin epithelium. They are thus organized into small and delicate villi, crowded close together. These simple papillae will become, in the fully formed glandular organ (Plate VI., a), the columns of connective tissue which rise and constitute the walls of the calices. FourtH Preriop. — We may assign to this stage the proliferation of these simple villi into other lateral villi. These lateral villi will be represented in the com- pletely formed cotyledon (Plate VI., 4, 5,) by the numerous horizontal follicles of the interior of the calices. Fiera Perron. — This comprises the union of the lateral ramifications of a villus with those of the neighboring villi. Srxta AND Last Perion. — It is now that, after the union of the above-named ramifications of the villi, the calices of the new glandular organ are complete, as well as the internal follicles that are superimposed upon each other. They are illustrated by diagram in Plate I., Fig. 2, and represented according to nature in Plate VI. 154 APPENDIX. _ SECTION II. THE SHEEP. In the memoir I scarcely touched upon the ana- tomical structure of the cotyledons in the sheep. I limited myself to the assertion that the differences between the cotyledons of cows and those of sheep were more remarkable and more important than had generally been stated, specifying the concave form in the one and the convex in the other. Now I am able to add that the cotyledons of the gravid uterus of sheep are formed on the interior by trabeculz clothed with epithelium. They rise irreg- ularly from its internal uterine walls, and are distrib- uted without order into lateral ramifications, which adhere to and cross each other, thus leaving spaces or intermediate and irregular cavities which are oc- cupied by voluminous tufts of chorial villi. It is thus that, while it exists and performs its functions, the glandular organ of the sheep preserves the forms indicated for the fifth genetic period of the cotyledon of the cow. Briefly, the glandular organ of the sheep repre- sents a normal arrest of the successive development of the glandular organ of the cow; it allows us to see constantly and with the unaided eye what in the lat- ter animal may be observed by the aid of the micro- scope for a limited period. SECTION III. THE MOLE. The simplest form of the uterine cotyledon that I have pointed out in the sheep is also observed in an APPENDIX. 155 animal with a single placenta. This animal is the European mole. Such a fact seems to me worthy of special mention. It not only brings the form of sin- gle placenta near to the cotyledons of the ruminants ; it does still more. In an interesting work of Professor Bruch, of Strasburg,’ with which I was not acquainted at the time my memoir was published, it is very clearly demonstrated and represented by plates that among the inferior vertebrates, such as the squalide, the in- ternal uterine surface is clothed during pregnancy with an infinite number of vascular villi covered with epithelium. In these animals, consequently, the maternal por- tion of the placenta would be represented by the first period of formation that I have noted in the cotyle- dons of the cow. SECTION IV. THE HIND. The anatomical differences that I have indicated are not the only ones to be met with in the gravid uterus of the ruminants; and I do not intend even to name them all. I have had, however, the opportunity to study a cotyledon of a hind (Cervus avis), and I have assured myself that the differences between it and those of the cow are not limited, as Harvey says, to the less number in the hind, nor to their reputed smaller size.” 1 Études sur l’Appareil de la Génération chez les Sélaciens. Stras- bure, 1860. 2 See Memoir, page 51. 156 APPENDIX. The cotyledon of the hind that I have been able to observe has the form of a kidney. Its longitudi- nal is much greater than its transverse diameter. The first measures a little less than eight centime- ters ; the second, a little more than five; the circum- ference twenty-one, and the thickness three and one half centimeters. This voluminous cotyledon arises from a narrow fold of the mucous membrane in the connective tis- sue, of which we perceive a rich net-work of large vessels. From the surface of this fold there is devel- oped a great number of tubes or glandular follicles crowded close together, of a length corresponding to the thickness of the cotyledon. These follicles are tunnel-shaped. The transverse sections show the different diameters, ten or twelve hundredths of a millimeter at the orifice which gives entrance to the villi of the chorion, and two or two and a half at their base. These transverse sections present the exact figure of a honeycomb with round cells. One can form a precise idea of the structure, as well as of the anatomical elements constituting the glandular portion, of the placenta of this species of deer by looking at Plate V., Fig. 1, 6, 6, which repre- sents a transverse cut of the maternal organ in the mare. APPENDIX. 197 III ON THE FORMATION OF THE SINGLE PLACENTA IN THE CAT, THE HARE, AND THE GUINEA-PIG. In treating of the anatomical structure of the sin- gle placenta in the mole, I have already pointed out the analogies which it has with the cotyledons of a ruminant, — of the sheep, for example. I have since met with other differences in various single placenta of certain animals. ‘These conditions, which I could not elaborate in my memoir, further confirm, by their great variety, the single type of the glandular organ. Here I shall content myself with reviewing the mode of formation of the placenta of the cat, and I shall add to this review some observations upon that of the hare and of the guinea-pig. They will serve to demonstrate that if a veritable and actual neoformation of the glandular organ is constant it may yet take place by means of a histo- genetic process different from that which I have de- scribed in the cow, namely, by the production of a special cellular tissue formed of cells proper, analo- gous to those I have represented in treating of the decidua serotina of the human species, in Plate X., fies. 0,6, and Fis. 2,/, f. In the edentata, also, the glandular organ is the product of the successive transformation of these cells; and in that case, as well as in man, this phe- nomenon takes place contrary to the ordinary laws which govern the formation and the development of the permanent glands in living beings. 158 APPENDIX. The existence of the decidua serotina in animals had been denied, as I have already remarked. I have pointed out the importance of it in the human spe- cies. In following the mode of formation of the placenta in the cat, I have become convinced that, in that ani- mal also, there takes place upon the surface of the folds of the uterine mucous membrane, at the place where the placenta is formed, a neoformation of very delicate cells, which finally, after successive transfor- mations, constitutes the new glandular organ. I have stated that the same thing takes place in woman, though in its forms the glandular organ pre- sents the same differences that I have noted between the placenta of woman and that of the dog. What I now add is, that in these two carnivora, the dog and the cat, the neoformation has the same origin as in woman, that is to say, in the special cellu- lar elements which represent the modified serotina. A very important peculiarity will be offered us in connection with this subject by the placenta of the - hare, of which I shall treat after having briefly indi- cated the formative process of the placenta of the cat. SECTION 1. THE CAT. The uterine mucous membrane of the cat under. goes, during pregnancy, remarkable modifications, both at the places where the ova are arrested and in the portions of the uterine horns which remain empty. I shall notice these changes separately, beginning APPENDIX. 159 with those which are observed in the empty portions of the uterine horns. It was already known that the mucous membrane of the uterus is swollen during the rutting period and the period of pregnancy. The changes which it presents during this tumefaction have not been speci- fied, that I am aware of, with the exception of a greater flow of blood and the expansion of the utricu- lar glands, remarked by Malpighi. Now my observations upon the cat have demon- strated to me that after the tenth day of pregnancy the uterine mucous membrane is so tumefied in the vacant portions of the uterine horns that the result is a complete obstruction of the cavity of the uterus. In this way the ovum remains confined at the point where it is arrested, in a cavity closed in upon all sides. In proportion as the ovum is developed, and as the placenta is organized, forming relations of a certain duration between the ovum and the uterus, the cavity of the horns is reéstablished, and that not in consequence of the decreased hypertrophy of the mucous membrane, but because the increase in vol- ume of the uterus enlarges the whole circumference of it, and the cavity of the horns also shares in the enlargement. The epithelial layer of the uterine mucous mem- brane, which forms a smooth and lubricated pelli- cle (velamento) in the non-gravid cat, is transformed, by means of the vascular hyperplasia and by the sub-epithelial connective tissue, into folds which pre- sent, during gestation, the appearance of voluminous elandular follicles, like those of the uterus of the rab- bit, as represented in Plate VII, Fig. 1. Upon the 160 APPENDIX. increase in volume of these folds depends the com- plete occlusion of the cavity of the uterus at the places where the ovum is not arrested. With the progress of the pregnancy and the reés- tablishment of the cavity, it is easy to distinguish that the folds present at the sides numerous festoons, a disposition that Leydig affirmed to be normal in the non-gravid uterus of certain animals. In recalling these observations in my memoir, I also remarked that that anatomist had suspected that these great festooned folds of the uterus of certain animals might represent under an enormous develop- ment the extremely small glandular follicles or mu- cous crypts to be met with in the uterine mucous membrane of other animals. The changes that I have named in the uterine mu- cous membrane of the cat represent successively the most remarkable forms and differences that anato- mists have found to exist in the uterine mucous membrane of mammals, and it appears to me that observations confirm the supposition that Leydig brought forward when writing philosophically upon the subject of anatomy. At all events, these obser- vations lend probability to it, and I believe support me also, when, according to Bischoff, I considered the epithelial layer which lines the uterus of woman, and the cotyledons of the non-gravid uterus of the cow, as the simple and elementary form of a mucous membrane. At the place where the ovum has been arrested the uterine mucous membrane of the cat assumes at first a follicle-like appearance, as is represented in the 1 See Memoir, page 41. APPENDIX. 161 rabbit (Plate VII, Fig. 1). The folds, and conse- quently the depressions, are very small. Where the placenta is not formed they promptly disappear, and the mucous membrane becomes again smooth on ac- count of the distention which the increase in size of the ovum produces upon the uterine walls. At the point where the placenta is formed, on the contrary, the epithelium which covers the slight follicles that have been developed seems to become soft and to take on a tomentose appearance. At the same time, from the sub-epithelial connective tissue, proliferates another tissue of rounded, soft, and delicate cells which blend with those of the softened epithelium. The form of the follicles is preserved by the elevation of this tissue of neoformation into straight, slender lamellae, at first vertical and covered with a delicate epithelium which corresponds to that which lined the uterine mucous membrane. Between these lamina produced by the cells of new formation are insinuated laminated prolonga- tions of the chorion, where, only later, do we distin- guish the vessels. During the progress of the formation and the de- velopment of the maternal portion of the placenta the lamelle are elongated without increasing in thickness, and, under the pressure of the growth of the ovum, they fold and refold over each other, until they present precisely the structure of the perfected glandular organ, as I have demonstrated in the pla- centa of the dog (Plate VIII., Fig. 2). There is, however, a capital difference. During this period of formation the lamina of the new tissue are single, but when the glandular tubes shall be 11 162 APPENDIX. formed, as in the above-named figure, each tube will be composed of the half of two folds which are united together, inclosing the vessels that have been formed in the chorial lamin®, interposed from the very origin of the placenta between the lamelle of neoformation. The volume of the folds which rise from the uter- ine connective tissue does not differ from that of the completely formed glandular tubes. It follows that it is easy, at first view, to take one for the other, and to confound a fold, sinuous in shape, with a complete follicle having the same kind of conformation. But it is not difficult to avoid this error by ob- serving with attention the distribution of the utero- placental vessels, whose canalization is soon distin- guishable in the midst of the cells of the new-formed lamina ; on the contrary, the vascularity of the cho- rial lamine, that is to say, the foetal portion of the placenta, is not yet formed. Continuing the observations upon the progressive development, it is also easily seen that while the vas- cularity of the lamina of the chorion is being estab- lished the vessels are surrounded by the lamina of new formation, and the half of a fold blending with that half which is in contact with it constitutes the long and sinuous glandular follicle which I have de- scribed in the placenta of the dog, and which is not different from that of the cat. The mode of union of the uterine lamin®, which form the glandular follicles and surround the vessels of the chorion, explains the numerous communica- tions which the vessels of the foetal placenta preserve with each other (Plate VIII., Figs. 1 and 2, e, e), APPENDIX. 163 which remain, however, all included in the complica- tions of the glandular follicles of the maternal pla- centa. I have nothing to add to what I have written upon the completely developed placenta. The addition or modification that is required does not, therefore, concern the fact itself, but my manner of judging it. I had believed that that which de- pends upon a neoformation of special histological ele- ments was itself dependent upon the transformation of the folds of the preéxisting uterine mucous mem- brane. I must now, with regard to the utricular glands, fill a vacancy left in my memoir. Positive observations upon what becomes of these glands at the place corresponding to the placenta were altogether wanting. Even those who had be- lieved that, at the beginning of pregnancy, at least, the villi of the chorion penetrate into the utricular glands, were forced to confess that they had never met any traces of these glands in the placenta. Florinsky very recently affirmed the same thing, after having made the most minute researches in or- der to find them.! Now, in following the mode of formation of the placenta in the dog, I have been able to establish a precise observation upon this point, an observation which led me to discover an error that I had com- mitted, as I have pointed out above. At the tenth day of gestation the dilatation of the utricular glands is already remarkable at the place 1 Protocols des Vereins russischer Aerzte zu S. Petersbourg, page 141. 1863—64. 164 APPENDIX. where the ovum was arrested. Their diameter ex- | ceeds by a third that of the same glands in the empty | portions of the uterine horns. This dilatation must be very rapid. Between the sixth and the tenth day at the point where the placenta begins to form the glands show themselves so enlarged and distorted that they resemble enormous cavities. Their epithe- lium is in proliferation. Consequently, those who do not follow closely the transformation peculiar to these glands from the beginning to the end of preg- nancy have great difficulty in recognizing them, and I was myself very far from the true inference while studying the fully-formed placenta. On reading my memoir again, it will be seen how I was deceived as to the cavities that I saw. In the dog, also, they are formed out of the utricu- lar glands thus distorted, and I took them for the culs-de-sac of the large folds of the uterine mucous membrane, of which I believed that the maternal pla- centa was formed. | In Plate IX., d, d, we see these cavities, which are really, as I have just said, only the utricular glands, thus dilated and distorted from the first periods of gestation. Now, the plate needs no change as re- gards anatomical truth; it is the interpretation I had given of it, which needs the modifying and correc- tion which I proceed to make. In the first period of placental formation in the cat, the production of the phenomenon is readily followed. It is also seen how the connective tissue surrounding the utricular glands serves as a direct support to the special new tissue, formed of delicate, rounded cells, analogous to those I had described APPENDIX. 165 in the serotina of woman, and which compose the lamelle that, as I have stated, are first lifted up and afterwards transformed in order to be reunited into glandular follicles. The dilatation and rapid degeneration of the utricu- lar glands lead us to believe that this phenomenon is produced in consequence of the occlusion of their ori- fices, occasioned by the prompt neoformation of the cells constituting the glandular or maternal portion of the placenta. We ought, therefore, to consider these cells as rep- resenting the serotina in the human species. I think it unnecessary to add that it is precisely the portion of the mucous membrane of the uterus where the transformation of the utricular glands takes place, which degenerates with them after deliv- ery into a fatty substance, and disappears gradually, as I stated in the study upon the dog. The cellular elements of new formation have no analogies in healthy adult organisms, but only in the tissue which Virchow calls mucous, and which abounds in embryo. This would suffice, without taking into account re- marks already made, to bring the mode of formation of the single placenta in certain animals near to that of the human placenta. In both cases alike, the glandular organ owes its origin toa neoformation of special cellular elements, which in woman takes the name of decidua serotina ; its existence being denied in animals for want of exact observations. But only after having observed the first periods of placental formation could this be positively asserted. 166 APPENDIX. SECTION II. THE HARE. In order to be convinced that the special cellular tissue which, as I have said, is formed of the sub- epithelial connective tissue of the uterine mucous membrane in the cat is truly that which constitutes the serotina in woman, it is only necessary to study the placental structure of the hare. In the hare (lepus tumidus) the phenomenon which I am about to explain is much more clearly seen than in the placenta of the rabbit; and this difference be- tween the placenta of these two so closely-allied spe- cies is not the only one. The placenta of the hare is developed by a thick layer of round cells, as voluminous as those of the serotina in woman. The transverse sections of this raised layer of sim- ply cellular tissue allow us to see in its interior nu- merous quite large cavities, various in form; the smallest are full of blood. This offers an example, or is rather the elementary form, of the large lacune of the human placenta seen in an animal. The larger cavities are filled with a somewhat dense fluid of a caseous appearance, especially at the bottom, that is to say, towards the uterine surface of the placenta. The presence of large cells in this fluid leads to the supposition that it is formed in the interior of the cavities by the deliquescence of the large cells of the thick serotina detached from the internal wall of these cavities. . Only towards the foetal surface of the placenta of the hare, the glandular tubes into which the very APPENDIX. 167 short villi of the chorion penetrate are formed by the cells of the serotina, which the walls have fur- nished to the larger cavities. In this animal, the ser- piginous character of the glandular tubes is only ob- served upon the most superficial layer of the foetal surface of the placenta. It is then settled beyond doubt, that in animals also a serotina exists. In the hare it is even very thick. The form of the elements which compose it is identical with that of the elements of the human se- rotina. To sum up, if the variation of development be- tween the placenta of animals and the human pla- centa is very great, the unity of the formative type of the glandular organ is only more clearly and surely demonstrated by this very difference. SECTION III. THE GUINEA—PIG. Another difference between the placenta of the rabbit and that of the hare is more clearly seen in the guinea-pig, and a very important conclusion may be deduced from it. In the hare, but much better in the rabbit and in the guinea-pig (cavia cobaya), when the placenta is completely formed, we see that the very numerous and complicated vascular loops which constitute its foetal portion are surrounded by a layer of large cells of the serotina, which have the appearance of large corpuscles of the connective tissue. This cellular layer presents the characters of the walls of the glandular follicle without in reality possessing all their anatomical parts. 168 APPENDIX. Is then my statement regarding the structure of the maternal portion of the placenta invalidated by this observation in some few animals? i On the contrary, it only confirms the anatomo- physiological aphorism already admitted by science, namely, that secretory cells are sufficient to repre- sent a glandular organ. But there is more to be said upon this subject. In the human species itself, during the first periods of placental formation, the villi of the chorion are in immediate contact with the cells of the serotina. Therefore the placenta of the hare, complete and at term, and yet more that of the guinea-pig and of the rabbit, shows in an easy and permanent way the transitory and incomplete first period of placental formation in woman; as the numerous vascular villi, observed by Bruch upon the uterine surface of the squalide, represent the first periods of formation of the placenta in the cotyledons of the cow. Thus it becomes necessary to modify the explana- tion of Plate VII., Fig. 3, from that given. What I had supposed to be the beginning of the neoformation of the glandular organ in the rabbit is in reality only the mass of the cells of the serotina, which lean against the villi without being trans- formed. The phenomenon in question is easily ob- served in the first stage of formation; but when the placenta is organized the enormous development and the very complicated ramifications of the vessels of the foetal placenta constitute a kind of agglomeration of vessels, crowded and pressed close together, which renders the cellular layer of the serotina much more difficult of demonstration. APPENDIX. 169 IV. ON THE FORMATION OF THE PLACENTA IN WOMAN AND IN THE MONKEY. SECTION I. WOMAN. In the human species, better and more surely than elsewhere, I had been able to study the formation of the glandular organ by the cells of the decidua serotina. The observations I have just described upon the development of the placenta in the cat, and upon the completely formed placenta of the hare, support my conclusions. Those I have since made directly upon the mode of formation of the human placenta will confirm them still further. The proliferation of the characteristic cells of the serotina (Plate X., Fig. 1, /, f, and Fig. 3, 6, 6) is much more abundant in the uterine region, which corresponds to the place where the ovum has been arrested. A part of the chorion is thus brought into immediate and direct contact with the new- formed cells, that is to-say, with the serotina. When the villi of the chorion begin to develop, even be- fore their vascularization, they insinuate themselves, spread out, and ramify between the cells of the sero- tina. Hence in the first stages of formation of the human placenta, in vertical sections as well as in horizontal ones, we find under the microscope the self-same figure of villi cut across, which resemble perfectly round disks in immediate contact with the cells of the serotina, and entirely clothed by them. 170 APPENDIX. Some of these villi are also cut in a longitudinal di- rection. In the latter, better than in the others, the external epithelium is clearly distinguished, which I had not been able to see with perfect certainty in the placenta at term. It follows from these facts, therefore, that during the first periods of development of the human placenta, the epithelium of the chorial villi is, without any doubt, in immediate contact with the cells of the sero- tina only. The vascularization of the maternal placenta takes place before the vascularization of the villi of the chorion, and before the complete formation of the foetal placenta. I have been able to pursue with ease the manner in which this is effected in two abor- tions, of one and of two months respectively. In the same way as the villi of the chorion penetrate into the foetal surface of the placenta between the cells of the serotina, so the vascular loops which spring from the uterine vessels insinuate themselves between the cells of the serotina through the uterine face of the placenta. The vascular loops are not distributed and do not ramify between the cells of the serotina; but during the early periods of gestation, they become diffused and dilated exactly like the capillary vessels in the erectile tissues. These dilatations augment by degrees and form large projections which rise towards the foetal surface of the placenta; still increasing in size, they at length surround the chorial villi, which remain, however, cov- ered with a layer of cells of the serotina. It is, in fact, these cells that are finally changed into a gland- ular organ (Plate X., Fig. 3). APPENDIX. 171 In the first stages, during which the small lacuna of the human placenta are formed, it is not difficult to ascertain the period when, together with the blood which they contain, the cells of the serotina are transformed into corpuscles of connective tissue, of which the fibrous walls of the same lacuna are after- wards formed, just as we see them clearly in the com- pletely developed human placenta (Plate X., Fig.1, 4). The transformation of the cells of the serotina into corpuscles of connective tissue, in proximity to the new lacune, which have an irregular shape, and in which it is not possible to distinguish the very thin wall of the dilated capillaries, might lead to the sup- position that these lacuna are the result of the rupt- ure of the capillaries, or of the gradual expansion produced by the sanguineous effusion. The observations of Robin and of Legros upon the dilatation of the capillaries in the erectile tissues do not permit this supposition ; and it is altogether elim- inated by the very easy demonstration which allows us to discover the epithelium of the circular sinus of the complete placenta, which forms a part of its lacu- nose system. The very delicate wall of the capillaries thus di- lated so enormously and strangely in the human pla- centa must of necessity lme the external walls of the glandular organ which surrounds the villi and which is composed of the cells of the serotina, I will state, however, that the most attentive and direct observa- tion has not yet enabled any one to distinguish this thin vascular membrane from the external membrane which covers the villi. All that I can add to what I have written upon the 172 APPENDIX. anatomical structure of the placenta has reference, as I have just indicated, to the first periods of its forma- tion, that is to say, its histogenesis. I review, therefore, what I have written upon this subject in the following manner. In no period of the development of the embryo does the maternal blood come in contact with the villi of the chorion. During the early period of development of the foetus, in the majority of the mammals that I have examined, the vessels are as much lacking on the part of the foetus as upon that of the mother. In the cat and in woman the nutrition of the foetus is carried on directly by an osmotic exchange be- tween the cells of the serotina and the mucous tissue of the villi, and in woman by means also of the epithelium, which I have not hitherto been able to observe in the chorial lamin® of the cat. When vascularization has taken place in the foetal and in the maternal placenta, the osmotic processes are established between the fluid secreted by the cells of the glandular part of the mother and the vascular part of the foetus. In the human species, and in certain animals with a single placenta, the glandular organ owes its origin to the neoformation of a tissue of special cells, which in the human species has received the name of de- cidua serotina, the existence of which in other ani- mals has, until the present day, been unjustly denied. The placenta at term in the hare and in the guinea-pig presents the first transitory period of the formation of the human placenta. When the cellular neoformation, or the serotina, APPENDIX. Le does not take place under the form of a layer of greater or less thickness, the maternal placenta is constituted by means of a special papillary neoforma- tion, such as we observe during its different stages of development in the cotyledons of the cow. In the elements of neoformation there is no change except in shape. In the cow, also, and in other ani- mals, the papillary projections show themselves un- der a special form of elements, which we call serotina when it presents a uniform layer of cells. This same mode of development may be reasona- bly supposed to exist in other ruminants, and even in some animals with a single placenta, as the mole, for example. With all this, I do not pretend to affirm that the two modes of placental formation observed and de- scribed are the only ones which take place among mammals. They are the only ones which I have so far been able to determine, and they seem to me suf- ficient to establish the fact that there is always a true and actual neoformation. The glandular organ which is the result of it de- parts during its development from all the known laws which govern the genesis of glandular organs in living beings; it cannot be confounded in any man- ner with the modifications of the mucous membrane, or of the preéxisting uterine glands. 174 APPENDIX. SECTION II. THE MONKEY. I come in the last place to fill another blank that I was forced to leave in my memoir. The conclusions which I had been able to make, up to that time, upon the anatomical structure of the completely formed placenta, not having been ex- tended to its mode of development, had led me to believe that the differences between the human pla- centa and that of animals were much greater and more important than they now appear. I then proposed a scientific question of positive fact, so to speak, and asked whether the placenta of the quadrumana would have the type of animals or that of the human species. In the mean time, my good fortune and the court- esy of my two colleagues, Professors Bassi and Ri- volta, of Turin, have enabled me to study a placenta at term of a Cercopithecus sabeus. Between the hu- man placenta and that of this species of monkey I have met with no notable differences. I can myself, therefore, answer the question which I had proposed in order that others might have the opportunity of resolving it. The type, and much more than the type, the anatomical structure, of the placenta of the monkey is identical with the placental structure of the human species. MONOGRAPH UPON THE UNITY OF THE ANATOMICAL TYPE OF THE PLA- CENTA IN THE MAMMALIA AND IN THE HUMAN SPE- CIES, AND THE PHYSIOLOGICAL UNITY OF THE NUTRITION OF THE FGETUS IN ALL THE VERTE- BRATES.! Wirg reverence do I recall the honored memory of Filippo Ingrassia, who, in the classic land which was the cradle of the revival of letters, eulogized at the close of the sixteenth century the fruitful union of human and veterinary medical science in his famous oration, published in 1568, entitled “ Quod Medicina Veterinaria formaliter una eademque sit, cum Nobili- ore Hominis Medicina.” Ata period so remote from our own, and when veterinarians were only poor far- riers, holding a very humble position compared with those skilled in human surgery, this was the happy intuition of a noble mind, which boldly outran the times, sowing the seed of that entire revolution which after three centuries comparative and experi- mental pathology have introduced into all medical instruction. The work of Ingrassia in Italy was carried on by others, among whom were Lancisi,? Ramazzini,’ Luigi, Galvani, and Gandolfi, who published at Bologna, in 1 Translated from the Transactions of the Academy of Sciences of the Bologna Institute, 1877. 2 Dissertatio Historica de Bovilla Peste. Rome, 1715. 8 De Contagiosa Epidemia que in Patavino Agro et tota fere Veneta Ditione in Boves irrepsit. Padua, 1712. 176 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 1817, “ Parallels between Human Maladies and those of Animals,” and Pucinotti, whose work on “ A Conta- gious Epizodty and on Contagions in General” ap- peared in 1825. It is unnecessary here to mention the numerous works of Alessandrini. It was he who, founding in Italy, and with us, the first museum of comparative pathological anatomy, procured a true glory for our university, which the most learned fol- lowers of medical science in Europe commended and admired as the ripe fruit of the good seed sown in Italy by the great Sicilian physician. This glory, all our own, was diminished not long since, and the ancient edifice erected with so much care and affection, and supported by the self-sacrific- ing labors of Italy’s most distinguished medical men, seems destined to immediate and certain ruin; but, happily, in the civilization of the present day, errors pass away and die with the men who taught them, while for science and its true followers the laborious conquests of human learning are never lost. Com- parative pathology will make its way among those who cultivate medical science throughout the civil- ized world, and history will gladly record the past glory of our Athens, where for a century was taught, not in vain, with Ingrassia, “ quod medicina veteri- naria formaliter una eademque sit, cum nobiliore hominis medicina.” But not by cherishing the memory of a glorious past, and not with the weak accents of useless com- plaint, is the pain of the present removed. It is with 1 By a royal decree, dated August 24, 1876, the Veterinary Institute was separated from the Medical Faculty in the Royal University of Bo- logna. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 177 study and unwearied application that the future is prepared and slowly matured. One of the most illustrious anatomists and histolo- gists of learned Germany has lately asserted that the human placenta, regarded as a whole, is a formation very spongy in character, abounding in blood, which does not easily allow investigation with the ordinary methods that are most useful in all anatomical re- searches, namely, the knife and injections, — and he finds in this the reason for the uncertainty that exists with regard to its intimate structure. The illustrious German somewhat forgets the important precept left us from the old Italian anatomical school, which was the same inculcated by Ingrassia for pathology, that it is of great service in clearing up intricate and diffi- cult questions of human anatomy and pathology to consult comparative anatomy and pathology. Kdolli- ker, in discoursing of the human placenta, contented himself with noticing simply and incompletely, by way of supplementary instruction, some of the mani- fold differences met with by observers in studying the placenta of mammals.’ He did not seek to ful- fill the more serious and important duty for an ana- tomical professor, who, after observing and studying the multiplied differences of form which are presented in one organ in different animals, endeavors, by means of careful and minute comparisons, to explain more readily the physiological unity or the office of the organ. Following the path traced out by our great mas- ters, and the instructions of Malpighi, advantageously 1 Kolliker: Entwickelungsgeschichte des Menchen und der hoheren Thiere, B. 1, s. 331. Leipzig, 1876. 12 178 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. applied by the moderns to inquiries into the process of evolution in the organs and tissues, I believe that by the aid of comparative anatomy I have attained the end aimed at in my long-continued studies on the structure of the placenta. I can now show, with some force and clearness, that where the usual ana- tomical methods fail in ascertaining the structure of the human placenta, comparative anatomy alone is able to reveal it, and to demonstrate the unity of the anatomical type of the placenta under whatever manifold forms and varying external appearances it may be presented in the different classes of mammals and in the human species. This conclusion, which I have reached after many years of assiduous research, is not only important in itself, but is the more so be- cause it goes beyond the limits of simple anatomy and invades the field of zodlogy. Learned men, like Owen, Huxley, and Kolliker, have placed as a basis of the fundamental distinctions in the mammalia the presence or absence of the placenta, or of facts con- nected with its intimate structure, which renders the path I now follow very difficult. If I shall be suc- cessful the merit will not belong to me, but to the university in which I was educated in medical knowl- edge, where my illustrious master learnedly ex- plained the pregnant teaching left us by Ingrassia, and to my having pursued in the study of the human placenta the method adopted by Fabricius of Acqua- pendente! three centuries ago. I shall divide my work into two distinct parts, since no better arrangement of the important subject I have undertaken presents itself to me. 1 De Formato Fetu. Padua, 1604. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 179 In the first I shall indicate some new observations of facts which serve to explain the origin of the ele- ments of the decidua and the maternal portion of the placenta, a point which hitherto has lacked a clear and positive demonstration. I shall notice some pe- culiarities in the rodents, heretofore unsuspected, rela- tive to the complete destruction of the uterine mu- cous membrane and the subjacent parts before the formative process of the decidua takes place. I shall then describe the structure of the fully developed placenta in the Cavia cobaya, in which, besides notable peculiarities relative to the reflected decidua, we find in a single placenta the remarkable example of the form and structure seen in the multiple placenta of a ruminant united with that which is observed exclu- sively in cases where the placenta is single. In sum- ming up these observations, I shall establish the fact of the destructive process not only of the uterine mu- cous membrane, but of the thick, glandulo-vascular layer beneath, leaving bare the inner muscular wall, —a process taking place beyond question in the ro- dents immediately after conception. Finally I shall endeavor to demonstrate that the same destructive process, differing only in degree, takes place in the uterus of all the mammalia, and is indispensable in all cases to the establishment and development of the neo-formative changes from which will result the ma- ternal portion of the placenta. These facts, hitherto imperfectly considered, or even entirely unknown, open the way for showing, in the second part, that, amidst the manifold and striking anatomical differences met with in the placenta in the different classes and species of mammals, there is 180 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. : always preserved an unfailing typical unity of ana- tomical structure, and that the variety and the multi- plicity of forms depend only on a few very simple modifications observable in the two fundamental parts which constitute the placenta in the mammifera and in the human species. This knowledge of the typical forms of the two constituent parts of the placenta wonderfully helps in judging of the villi, which are developed after con- ception in the gravid uterus of certain viviparous fish, and which represent the typical form of the ma- ternal portion of the placenta in mammals, as a pri- mordial manifestation of the placenta in vertebrates. By this link between the oviparous vertebrates and the mammalia is clearly shown, in all, the physio- logical unity, by the mode of nutrition of the , foetus, completing on this side the modern discoveries in embryology. IE The opinions which have hitherto been entertained concerning the origin of the cells which enter so largely into the formation of the maternal part of the placenta have been exceedingly vague and uncertain, when they were not altogether false, as were the teachings of those who asserted that the maternal portion of the placenta was merely a tumefaction or a transformation of the uterine mucous membrane. In time past I showed myself inclined to believe that these cellular elements might proceed from a trans- formation of the corpuscles of the sub-mucous con- nective tissue of the uterus, and from a proliferation of the newly-formed elements, but at the same time UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 181 that I pointed out the facts which seemed to confirm this idea, I stated that so distinguished an anatomist as Waldeyer had informed me of a suspicion he enter- tained, to the effect that the new cellular elements originally constituting the different portions of the decidua, and then the maternal part of the placenta, might proceed from the walls of the uterine vessels. For a long time no positive observation was afforded me for holding either opinion as demonstrated, and, for my own part, I confess that the answer to such inquiry did not at first appear to me to have the deep scientific interest that really belongs to it. Turner, in the first part of his last important work? on the placenta, although concisely affirming with Owen that without decidua there is no formation of placenta, does not touch the important question of the origin of the decidua; and Kolliker, a no less distinguished anatomist, confines himself to the re- mark? that “the decidua is a transformation of the uterine mucous membrane, and not a new membrane, or the product of an exudation, as was once believed,” and as farther on he says® that “the different por- tions of the decidua have originally the same struct- ure,” the meaning seems to be that the origin of the decidua is to be found in the transformation of the preéxisting elements of the uterine mucous mem- brane, which, as we shall see, is very far from the truth, the decidua being due to a real neo-formative process, as I of late have endeavored to prove. 1 Lectures on the Comparative Anatomy of the Placenta, page 113. Edinburgh, 1876. 2 Entwickelungsgeschichte des Menschen und der Hoheren Thiere, page 326. Leipzig, 1876. 8 Op. cit., p. 336. 182. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. It is, however, well to notice here that this famous anatomist does not attempt to show which elements of the mucous membrane they are that compose the decidua, nor by what means they are transformed, although such an investigation should be of the high- est interest for him, since the crypts or the simple and compound glandular follicles which I demon- strated to be of new formation, and to proceed from the previous neo-formation of the cells of the decidua, in the case of diffused and multiple placenta (obser- vations largely confirmed by Turner in the above- cited work), are with Kolliker only deepening de- pressions or tumefactions of the preéxisting uterine mucous membrane, formed during pregnancy and dis- appearing after delivery. The remote cause of these supposed tumefactions and hollows, as well as that of the transformation of the uterine mucous membrane for the development of the decidua, thus remained in the darkness of uncertainty. I have elsewhere remarked that in the females of multiparous mammals having a single placenta, whether of zonarial or of discoidal form, the fecun- dated ova, when they have descended into the ute- rus, remain sequestered in the places where they were arrested, because in the intermediate segments of the uterus between ovum and ovum, the uterine mucous membrane was so tumefied that .its longitudi- nal folds intersected each other in such a way as to | produce a complete occlusion of all the segments of the uterus that remained empty. I have met with this considerable tumefaction of the mucous membrane over the whole internal sur- face of the uterus of a dog in heat, and the turges- es Fe eS gr UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 183 cence of the mucous membrane was already such that the uterus being cut across, its internal cavity ap- peared like a stellate fissure, the tumefied folds of the mucous membrane being united with each other. In this state of turgescence in the uterus of the dog in the state of heat which precedes conception, as well as when conception has taken place, no change is observed in the histological elements in the portions of the uterus where the ova have not been arrested. The increase of volume in the utricu- lar glands which is very quickly initiated in the ear- liest periods of conception is not sufficient to cause the considerable enlargement in the part, which is evidently due almost exclusively to a strong vascular turgescence. This turgescence of the uterus, already observed by other anatomists at the commencement of gestation, has been very recently noticed by Tur- ner in the uterus of the cat,’ and it is the only known fact that serves to point out that in some cases prior to conception, in others at that period, all the inter- nal surface of the uterus is prepared for those later changes which will be indispensable at the indetermi- nate point or points where the ovum or the ova are to be arrested after fecundation. It is evident that the only way of ascertaining the origin of the cells of the decidua is to make the in- vestigations on the gravid uterus at the first moment of conception ; but this way had already been pur- sued with regard to animals having diffused and mul- tiple placenta, and with those also where the pla- centa is single, without obtaining facts so clear and evident as to warrant a positive opinion on this inter- I Opy ett; pu 72 184 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. , esting subject, and it has been only very recently that I have succeeded in solving the difficult question by examining the gravid uterus of a rabbit at the precise moment of the beginning of the formation of the placenta. I think the favorable time for this examination is very transient, and therefore offer the illustration of it in Plate I., Fig. 1. Fortunately, however, the ob- servation is convincingly repeated in the examination of the placenta formation in the carnivora, but of this I shall treat subsequently. The figure accurately represents the transverse section of a portion of the gravid uterus in the rab- bit, about fifteen days after conception, at the place where the placenta begins to be formed. Here are at once seen three parts clearly distinct from each other, which correspond (a, a) to the muscular tissue of the uterus, on the inner surface of which the pla- cental neoplasm projects (0, ¢). Above this is shown (d, d) the old uterine mucous membrane, tumefied, and about to be destroyed. If we give an attentive examination to these parts, two very interesting facts are at once apparent; first, that the utero-placental vessels (0,5) have a lumen almost double that of the uterine vessels from which they proceed (a’, a’), and, moreover, that notwith- standing their greater volume, they show on their walls none of the anatomical characteristics which serve to distinguish the arterial from the venous ves- sels, and which are clearly visible in the uterine ves- sels. The second fact is that these vessels, instead of the ordinary walls, are surrounded with a uniform envelope of cells of a special character, which are ex- UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 185 actly those found constituting the cells of the decidua serotina and the maternal placental tissue (c, c). At first sight the vessels of the vascular net-work, clothed with a layer of special cells which stand out from the uterine muscular tissue and represent the placenta in this first phase of development, might be supposed to be the vessels of the vascular net-work of the old mucous membrane that had undergone transformation, and which I have already described as remarkably tumefied in the uterus of the dog even before conception has taken place. But this suspi- cion is removed by the special characteristics before pointed out in the walls of the vessels, — a fact on which I shall hereafter have occasion to dwell in or- der to show that it is the endothelium alone that forms their walls. A stronger argument, however, than any minute observation, is the exceptional fact that all the old uterine mucous membrane, including the crypts that represent the utricular glands in this animal, and the underlying connective layer with its vessels and nerves, is already observed at this stage of development of the placenta, greatly changed, and in course of complete destruction, detached from the whole internal surface of the muscular tissue of the segment of the uterus where the ovum has been ar- rested, and above the placenta at the point where that is formed (Plate I., Fig. 1, d,d). This separation and great destruction of the uterine mucous mem- brane and of the connective layer beneath, which I shall examine more minutely in other rodents, I have pointed out and represented in the rabbit, be- cause they show, beyond all doubt, that the placenta in this animal cannot be produced by the transfor- 186 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. mation of the anatomical elements of the mucous membrane existing before the act of conception, and. that the utero-placental vessels as well as the uniform layer of cells which surround them are owing to a real neo-formative process. In all animals having a single placenta that have hitherto been examined, the decidua vera and the decidua reflexa are alike due to a neo-formative proc- ess. The decidua vera, when detached from the in- ner wall of the uterus, consists of the elements of new formation, which have been arrested in their de- velopment, and those of the uterine mucous mem- brane, which were superimposed upon the new- formed cells. According to this view, in the rabbit the decidua vera and, what is of more importance, the decidua reflexa are both wanting, being repre- sented only by the old uterine mucous membrane and the connective layer beneath, wholly detached from the inner surface of the uterine muscular tissue, and to be seen later in course of complete destruction between the external wall of the ovum and the inter- nal wall of the uterus. We shall presently obtain more noteworthy examples in other rodents of the destructive process so extensively sustained by the mucous membrane and the subjacent parts, as far as the uterine muscular tissue, immediately after con- ception, and of the neo-formative process of the de- cidua vera and reflexa. These conclusions, demon- strated by observations on the gravid uterus of the rabbit, confirm my previous statement, that the ves- sels themselves are of new formation, and from them are developed the cells of the serotina constituting the maternal portion of the placenta, and exclude by UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 187 a very evident fact any participation whatever of ele- ments preéxisting in the uterine mucous membrane in the formation of the placenta. The opinion, or rather the suspicion, thrown out by Waldeyer on the origin of the cells of the serotina was approximately true, but not the actual truth, since it is not from the preéxisting vessels of the uter- ine mucous membrane that these cells arise, but the vessels themselves are of new formation and of spe- cial structure, and therefore constitute an integral part of the placental neoplasm. I have above indi- cated that the origin of the cells of the serotina and placenta from vessels of new formation can be under- stood without difficulty by examining the structure of the placenta, even when fully developed, in the carnivora, which I shall now briefly consider. Carefully studying the observations instituted by Turner on the anatomical structure of the placenta of the dog, the cat, and the fox, as well as that of the seal and the hyrax, all of which have a common type, I was glad to find that so illustrious an anatomist has confirmed my first observations on the placenta of the cat and the dog, namely, that the villi of the cho- rion do not enter into the utricular glands to form the placenta, as Sharpey and Bischoff had taught;! that as these utricular glands do not open into the cotyledons of the gravid uterus in the cow, as Bisch- of, Eschricht, and Spiegelberg had admitted,’ so these glands do not open into the placental crypts in the cat ;* and that the crypts which are formed in the first period of gestation in the placental region of the carnivora are not owing to a simple enlarging of the 1 Turner, Op. Clty Pe Ca. 4.Op. cit, pi 69. 8 Op. cit., p. 74. 188 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. mouths of the glands, but are really of new forma- tion." | But I cannot agree with Turner that the aforesaid erypts, or, as I called them, glandular follicles, are produced in the dog and the cat, as well as in the sow and the mare, by an excessive growth of the in- ter-glandular part of the mucous membrane which is folded over to form them? Nor can I admit that the morphological elements of the placenta in the dog, the fox, the cat, and the seal are indubitably like the crypts of the mucous membrane in the mare, a ceta- cean, or any other animal having a diffused placenta. Upon examining and comparing the descriptions given by Turner, and his accurate figures of the in- jected placenta of the fox,* with my own prepara- tions and statements on the placenta of the dog and the cat, I at once perceived that, if the observations of Turner were exact, I had fallen into a serious er- ror in my opinion of the intimate structure of the placenta in the carnivora that I had examined, hav- ing mistaken the utero-placental vessels of the ma- ternal portion for the proper vessels of the foetal portion, and, in consequence of this error, having re- garded as closed and new-formed glandular follicles, or glandular crypts of new formation as Turner con- sidered them, parts which in their form have nothing in common with the crypts or glandular follicles prop- erly so called. All those who have attempted to study the inti- mate structure of the placenta, and know the serious difficulties encountered at every step in this pursuit, 1 Op: Cit, p) 1a. 2"Op. cit., ps 75: °Opifei pali. 4 Op. cit.; Plate I, Bio. 15 4, 70. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 189 will readily understand that, not having previously injected the placenta of the carnivora, the mistake I made was not only very easy but almost inevitable. Nevertheless, I do not seek to excuse myself by showing how one may be drawn into error, nor to shield myself with the illustrious name and teaching of Professor Turner, who, even after performing in- jections, fell into the same error, and received as true, as I have pointed out, my first incorrect conclu- sions. Enough for me, that, stimulated by the obser- vations of Turner, and after repeating them, I have been able to correct my mistake, and through cogni- zance of it I have at length come to understand that, though in certain animals the glandular structure of the maternal portion of the placenta clearly appears under the aspect of crypts or common glandular folli cles, as when it has the diffused or multiple form, on the other hand, when the placenta is single, whether zonarial or discoidal, the common glandular form is completely disguised, although without losing the fundamental character of a secretory organ. It was by repeating investigations in this direction that the idea was finally reached of the single anatomical type of the placenta in all mammals. But before coming to the conclusions let us examine the facts. In the dog and the cat (and, as I have elsewhere shown, the same thing occurs in the human species also) the subjacent utricular glands at the place where the placenta is formed are dilated and altered in shape so as to produce a sort of trabecula with large meshes, or a spongy tissue, which is found be- tween the surface of the inner muscular tissue of the uterus and the uterine surface of the placenta. There 190 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. is a slight indication of this spongy condition seen in Plate I., Fig. 2, a, a, which shows a section of a pla- centa of a dog at term, with the vessels of the mater- nal portion injected. The placental vessels have a uniform diameter, and form a net-work of not very large meshes, which reaches as far as the chorion, with which it is firmly joined (4,4). In the chorion (c) are seen, cut across, the foetal vessels which, uniting, go to form the um- bilical cord. Every ramification of the net-work of the injected placental vessels is in direct relation with the uterine vessels, and everywhere surrounded by a uniform and rather thick layer of cells (2, 6’); therefore all the maternal portion of the placenta in this animal is formed from the vascular net-work and the sur- rounding cellular envelope. We have, in short, in a more complex and permanent manner, the exact rep- etition of the fact transiently observed in examining the placenta of the rabbit at the beginning of its de- velopment, and represented in Plate I, Fig. 1. In some placente, then, even at the close of gestation, we obtain positive proof that the cells of the serotina and placenta originate from the walls of the placen- tal vessels, which, in this case also, lacking the proper anatomical characteristics of ordinary vessels, are to be held as being themselves of new formation and special even by their exterior cellular covering. Again, by injecting the foetal vessels we have a clear and positive demonstration of the relations es- tablished between the foetal and the maternal por- tions. The injection of these vessels affords con- vincing proof that the arterial, as well as the venous UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 191 vessels, which have a very considerable diameter in the chorion that adheres to the placenta (c) imme- diately below this, form a thin, close net-work of cap- illary vessels in contact with, and branching out in the cellular covering that clothes the maternal ves- sels. This relation is shown in Plate I, Fig. 3, rep- resenting a horizontal section of the placenta of a dog, injected and highly magnified. Not only is the minute capillary net-work of the foetal vessels distributed among the cells which cover the large-meshed, maternal, vascular net-work, but the vessels also ramify among the cells of this envel- ope, as is fully shown at the points where the mater- nal vessel was cut in the section (9,9). This figure perfectly corresponds with that given by Turner of the placenta of the fox. Therefore the idea of true glandular follicles, or crypts, as Turner calls them, identical with those in the cetacea, the solipeds, and the ruminants, is no longer in any way tenable; but of this question I shall treat more minutely in the second division of this subject. At present it suffices that I have represented the plan of the placenta in the dog, in Plate V., Figs. 11 and 12, in order that every one may judge of the eorrectness of the idea indicated in the diagram by a comparison with the exact natural figures which I have explained, for it is from such facts that one arrives at a conception of the single anatomical type of placenta in the mam- malia. The separation and destruction of all the uterine mucous membrane and the subjacent connective layer in the segments of the uterine horn of the rabbit, 1 Op. cit., Plate I., Fig. 5. 192 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. where the fecundated ova were arrested, and the knowledge gained from this fact, that new vessels with walls entirely special are formed in the placenta, © upon the external surface of which the cells of the serotina proliferate from the very beginning of its development, have allowed us to recognize this same fact in the placenta of the dog at term. But this knowledge is not always acquired with so. much cer- tainty, or when it can be obtained it is only during so limited a period, as we have seen, in the rabbit that the origin of the cells of the serotina in many cases remains uncertain because the observation was not instituted at the right time. Finally, there are not wanting certain cases in which we can in no way de- cide whether we are dealing with a true neo-forma- tion of which the origin is unknown, or, on the other hand, with a simple transformation of the preéxisting anatomical elements of the uterine mucous mem- brane. Careful examination and study of different animals at different periods of gestation can alone remove the many uncertainties met with in regard to this; and from neglect of this sole way of arriving at truth, able anatomists have been silent as to the origin of the cells of the decidua, or, what is worse, have con- sidered as a tumefaction, or a transformation of the uterine mucous membrane, the development of the placenta, which is a true and actual neoplasia. The better to prove these assertions of mine, I will now present the observations which I have in- stituted upon the changes which the mucous mem- brane of the uterus undergoes in the first periods of gestation in the rat, because they confirm not only UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 193 that, in these animals, the whole uterine mucous mem- brane is not tumefied or transformed, but also that it is completely destroyed after conception in the place where the ova are arrested. Furthermore, in the rat there takes place a complicated neo-formative proc- ess which shows clearly enough that the new-formed anatomical elements are identical in the decidua vera as well as in the decidua reflexa and serotina, and that consequently it depends upon the point where the ovum attaches itself whether the decidua be- comes serotina, reflexa, or vera. The process of destruction in the old, tumefied mucous membrane at the place where the ova have been arrested is very rapid in the rat, of which I ob- tained positive proof by examination of the gravid uterus of a Mus musculus and of a Mus decumanus a few days after conception. In Plate II., Fig. 1, is given the transverse and complete section of a uterine seg- ment of a Mus decumanus, in which the ovum had cer- tainly been just arrested, as it had not yet completed the phases of the segmentation (Fig. 1, ce, and Fig. 2, e); and it is interesting to notice that already, from the very first moments of gestation, the ovum is every- where surrounded with a cellulo-vascular neoplasm which completely isolates it at the place where it was arrested (Fig. 1,7, f, and Fig. 2, c). There were but few relics of the old mucous mem- brane in the segment of the uterus in question, name- ly, the remains of some portions of utricular glands not yet destroyed, near the inner muscular layer of the uterus (Fig. 1, 9, g, and Fig. 2, d, d), and in the presence of a small cavity of triangular shape, at an internal point opposite the place where the ovum 13 194 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. was arrested (Fig. 1, d), which is still covered with the old epithelium of the uterine mucous membrane. This cavity for a time represents the cavity of the horn before pregnancy, but with the progress of the development of the ovum it entirely disappears, and it is exactly below the concave base of this triangu- lar opening (Fig. 1, 4) that in the rat the placenta is always developed. At the period of gestation now under examination is seen a slight fissure extending from this cavity as far as the ovum (Fig. 1, e). This has been determined by the turgescence and trans- formation that have taken place in the uterine mu- cous membrane. At the edges of this fissure, and towards the place where we now find the ovum (Fig. 1, e), the epithelium of the old mucous membrane is already lost, but everywhere, whether the epithelium remains or has disappeared, instead of the old ana- tomical elements of the former mucous membrane there is observed a formless mass of cellular ele- ments, amongst which winds a minute, vascular net- work (Fig. 1, 4,7, and Fig. 2,c). To give an exact idea of the changes wrought in the uterine mucous membrane at the places where the ova were ar- rested, and in those which remained empty, I have given in Plate IL, Fig. 2, a longitudinal section of the same uterus from which the preceding preparation was taken. In the middle is clearly seen the ovum (e) surrounded by the cellulo-vascular neoplasm (e). In the segments of the uterus which remained empty the external and muscular walls of the uterus are indicated at 5, 6, and the cavity of the uterus at f, f. It is easy to observe, as shown at g,g, the tumefied uterine mucous membrane with its utricular glands UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 195 intact. In this section there is no longer any trace of the triangular cavity, nor of the fissure just now referred to in Plate I., Fig. 1, d, which also proves the rapidity with which certain changes occur, since the two preparations were taken from the uterus of the same animal. The origin of the wall of the vessels of new for- mation in the cellular mass (c), which imprisons the ovum at the place where it has been arrested, cannot in the rat be positively-ascertained in this first period of gestation, and were it not for the plain demonstra- tion obtained by examining the gravid uterus of the rabbit, the first idea suggested by the study of the preparations is, that the new-formed mass proceeds from a complete transformation of the preéxisting anatomical elements. But the proof that in the rat, also, all the decidua proceeds from a cellulo-vascular neoplasm, of which there is no trace in the non-gravid uterus, is clearly seen by examining a later phase of development of the decidua and the placenta in these animals, as represented in Plate III I wish here to state that all the preparations and drawings for this work have been very ably made by my excellent assistant, Dr. G. Pietro Piano. In Plate HI. is shown half of a complete transverse section of a segment of the gravid uterus of a Mus musculus, in which the placenta has not yet reached the last stage of development. The decidua vera at this period of formation is al- ready detached from the uterus through the whole extent marked f and g. The portion g corresponds to that part of the primitive decidua which at the beginning of conception we observed nearer to the 196 UNITY OF TYPE INPLACENTAL DEVELOPMENT. ovum, the placenta in the rat being always formed where we remarked (Plate II., Fig. 1, 4) the base of that narrow triangular canal which still preserved the old epithelium of the uterine mucous membrane, and which represents the former cavity of the uterus. Upon the inner surface of the muscular tissue of the uterus (Plate III, 5, 3), corresponding to the place whence the decidua vera has been detached, there is already formed a new epithelial layer which alone, at this period of gestation, contains all the future elements that constitute the uterine mucous membrane in these animals, as well as the thick, vas- culo-glandular layer below it which is destroyed im- mediately after conception. The decidua reflexa (c) is seen to be formed of two clearly distinct layers, — the outer (d), which is in relation with the inner surface of the uterine muscu- lar tissue, being composed of cells analogous to those which we found to constitute the uniform mass of the cells of the decidua soon after impregnation, and the inner layer (e), which appears to consist of a sort of trabecula composed of enormous stellate cells; the spaces interposed between these cells are no other than the lumen of large vessels cut across. In the portion of decidua vera ( f) continuous with this the external layer of the primitive cells has entirely dis- appeared, and there remains only the cellulo-vascular trabecula, the structure of which is also lost in all the remaining part of the decidua vera (9). It is to be noticed that a species of very imperfect pavement epithelium (0, 0) covers not only all the internal sur- face of the different portions of the decidua, but like- wise extends over the whole foetal surface of the pla- UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 197 centa as far as the place where the chorion adheres to it (m). If it had not been demonstrated that the old epithelium of the uterine mucous membrane dis- appeared completely from the earliest period of preg- nancy, the aforesaid epithelial cover of the decidua vera might be regarded as a permanent residue of this last, but the observations show that such an opinion is not to be maintained, and that here, too, is new formation. In the portion of decidua that has become serotina (h) there is seen at this period of gestation the cellu- lo-vascular trabeculae of the primitive decidua, like a layer between the two clearly distinct parts in the placenta of these animals, the uterine, which I have called glandular because destitute of foetal vessels (2), and the foetal, in which alone are distributed the vessels of the cord (7). The large stellate cells which surround the ectasic capillary net-work in this portion of the decidua serotina disappear altogether with the progress of development, and the two parts of the placenta are no longer to be distinguished except by the presence or absence of the foetal vessels among the placental cells that clothe the maternal vessels. In the period of pregnancy now under considera- tion, the chorion (x) adheres to the placenta only at its central part (m), the further blending of the cho- rion with the margins of the placenta not occurring until later, and then precisely at the place where, as I have pointed out, the decidua reflexa is observed (e). Thus is formed that chorial bursa which hermetically closes the whole foetal surface of the fully-developed placenta. When I before described the placenta of the rat, I mentioned the gigantic stellate cells found 198 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. at this place, and I can now positively state that these represent the old elements of the original de- cidua vera in the place where it has become re- flected. Observations instituted on the complete de- struction of the uterine mucous membrane and all the subjacent parts as far as the uterine muscular tissue, acquaintance with the elements, characteristic in size and shape, which constitute the primitive de- cidua, and the changes sustained by these peculiar elements in the place where the placenta is formed and elsewhere during the period of gestation, plainly prove that in the rat, also, it is not the old elements of the old mucous membrane that are tumefied and transformed, but that the decidua and the placenta are alike owing to a true and actual neo-formative process. Remarkable, and of no little interest, are the ana- tomical peculiarities which the study of the formed placenta of the Cava cobaya presents. I did not have a favorable opportunity for following step by step its earliest phases of development as I was able to do in the rat. But soon after the descent of the ovum into the uterus I observed with much certainty, in the uterine mucous membrane, the same facts which I have enlarged upon in the discussion of the uterine mucous membrane of the rat, in the segment of the uterus where the ovum is arrested. At this period the destruction of the mucous membrane cor- responds perfectly with that I have described and represented in Plate IL, Figs. 1 and 2. Observations are wanting with regard to the formation of the primitive decidua. Plate IV., Fig. 1, shows half of a complete transverse section of the uterus and pla- UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 199 centa of the cavia fully developed. The decidua vera (c) appears composed of anatomical elements al- ready altered, which give no suggestion of their pre- vious form. That the old mucous membrane and the underlying vasculo-glandular layer are completely destroyed in this animal, also, we have ample proof from the observation I have mentioned, from the thorough change in the mucous membrane early in the conception, and from the fact now known that the inner muscular layer of the uterus (a, a) is found to be covered by a simple epithelial layer (4), pre- cisely as we have seen in the rat, which itself alone represents all the parts that have perished. A no- ticeable peculiarity seen in the decidua vera of this animal belongs to the epithelial covering with which it is furnished, as well on its uterine surface (c’) as on its foetal or inner surface (¢”). The external surface of the decidua vera already completely detached from the uterus appears cov- ered with an epithelial layer, but it cannot be decided whether this is of new formation, or is only the outer- most layer of the new epithelium, which was devel- oped on the uterine muscular tissue (5) that remains adhering to it in the act of separation. In the rat we have obtained only indirect evidence for the as- sertion that the epithelial layer that covers the inner surface of the decidua was itself of new formation ; in the guinea-pig we have positive proof, because we see it in direct contmuation with the epithelium of the decidua reflexa (4), which in this animal has a special organization, and clothes not only the pedun- cle, but the whole of the placenta, even when it has reached its complete development (/, /). 900 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. In its general form the placenta of the cavia is pedunculate, and except in the central portion of the foetal surface, which adheres to the chorion (J), is all covered, as I have said, by the decidua reflexa, which presents special and differing characteristics in the part which invests the peduncle and in that which covers the surface of the placenta. The decidua reflexa all around the peduncle of the placenta (e, e) has the appearance of a large fringed fold, and is, on the exterior, covered with an epithe- lial layer which might be thought a festooned folding of the old hypertrophic mucous membrane. That it is really owing to a neo-formation is convincingly shown by the quality of the rounded and special cel- lular elements observed in its interior(z), in continu- ation with those which form the peduncle of the pla- centa, and which are entirely different from the or- dinary corpuscles of connective tissue. It is proved further by the entire absence of the utricular glands, and by the special characteristics of the large utero- placental vessels which traverse its external portion (e), in which are none of the anatomical elements that serve to distinguish the arteries from the veins, though in their normal state their diameter is far less. In the place, then, where this portion of the de- cidua reflexa is carried over upon the uterine muscu- lar tissue (4) the proof of the neo-formation is better shown by an interlacing of utero-placental vessels, which in their transverse sections are seen every- where surrounded by cells of new formation. This anatomieal disposition, which is observed in this ani mal at one point only of the decidua reflexa when fully developed, corresponds perfectly with the facts UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 201 which I have pointed out in the study of the forma- tive process of the placenta in the rabbit, where I ob- tained positive proof that the cells of the serotina originate from the walls of vessels, themselves of new formation. In a limited portion, therefore, of the de- cidua reflexa in the cavia, and also when the pla- centa has completed its development, we obtain con- firmatory evidence as to the origin of the serotinal or placental cells; nor is it only the decidua reflexa sur- rounding the peduncle of the placenta that presents characteristics important enough to exclude all suspi- cion that we are not dealing with neo-formed ele- ments, for the same conviction follows an examination of that part of the decidua reflexa which nearly envel- ops the body of the placenta. This special external covering of the placenta furnished by the decidua re- flexa, which I have observed only in the guinea-pig, is formed from the large cells of the serotina. Al- though there is evident trace of these cells at the point where the decidua reflexa of the peduncle is borne upon the body of the placenta, their volume gradually diminishes, until this covering of the pla- centa having reached the place where the foetal vessels penetrate and the chorion adheres to the pla- | centa, these cells and the firm neoplasm that sur- rounds them are blended with the connective ele- ments of the chorion (g). On the placental side this layer of decidua reflexa covers a sort of superficial and vascular sinus, and on its external face is lined with an epithelial layer of irregular thickness (t, è), on which are here and there epithelial prominences rising, like buds of various shapes and sizes, from the surface of the placenta. 202 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. This singular epithelium is in direct continuity. — with the uniform epithelial layer that envelops the decidua reflexa in the peduncle of the placenta, and with that which clothes the inner surface of the de- cidua vera; therefore the neo-formation of this, too, seems to me indisputable. The central part of the peduncle of the placenta (x) consists of a loose, delicate, and very peculiar tissue formed of cellular elements, varying in size (n’) from gigantic cells to small round nuclei, irregularly dis- tributed in a mass of protoplasm of gelatinous ap- pearance. In the midst of this singular tissue, which holds the place of the old elements of the uterine mu- cous membrane, is observed a net-work of capillary vessels, irregularly ectasic, from which are formed the utero-placental vessels. Eschricht had already remarked the dilatations of the maternal vascular loops in the placenta of certain animals, and Turner finally confirms this observation in the placenta of the cat, the dog, and the fox. With much acumen he considers such dilatations as a first intimation of the lacunose circulation witnessed in the placenta in the quadrumana and in the human species! The ectasia which I have now noted in the small vessels of the peduncle of the guinea-pig corroborates the opinions entertained by Eschricht and Turner. We shall see the importance of this fact later. The anatomical structure of the placenta in the cavia is most singular, since although, as in the rat, it may be clearly divided into two parts, yet that por- tion which I have called glandular in the rat has in the cavia the exact form of a cotyledon of the cow 1 Turner, op. cit., p. 85. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 203 (0); I shall therefore call it cotyledonal, reserving to the other the name of placental, properly so called, because the relation of the foetal portion with the maternal takes place in this in the manner which we have observed in the placenta of the carnivora (p). To form an exact idea of the structure of the pla- centa in the cavia, we may imagine it an empty tun- nel, closed at the lower, narrower part. The upper annular and peripheral part of the tunnel (p) is formed from the placental portion, the lower part, the cul-de-sac, from the cotyledonal portion (0); the internal cavity of the tunnel is filled with the tissue and vessels of the chorion (9). The cotyledonal portion (0) rises from that singu- lar tissue I have spoken of as forming the peduncle of the placenta. It has the shape of a cup, the con- cave part of which presents a surface elegantly undu- lated and festooned. This surface consists of a con- tinuous layer, not of uniform thickness, of similar round cells set rather close together, and, at the place where the wave-like folds rise, there is a rich net- work of small, irregularly ectasic vessels. All the concave, undulate surface of this cotyledonal portion is completely filled with chorial tissue (g), in the midst of which the foetal vessels ramify. The iden- tity in form of this portion of the placenta in the guinea-pig with that of a small cotyledon in the cow would be complete if the chorial elements did not ad- here to the surface of the undulate layer of the cells which I have just pointed out, and which are no other than cells of the serotina disposed as are the placental cells of a vaccine cotyledon. In the placenta of the cow both the foetal and ma- 204 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. ternal portions have a proper epithelium, and are separate from each other, while in the cavia the epithelium is wanting in both, and they are joined together. To give an exact idea of the anatomical structure of this cotyledonal portion of the placenta of the cavia, I represent a small section of it, highly magnified (500 diameters), in Plate IV., Fig. 3. At 6 is indicated the layer of cells that line the cavity of the cotyledon, at a the net-work of the maternal ectasic capillaries, from the walls of which is elabo- rated the before mentioned undulate cellular layer, at c and d the chorion and its vessels, to show clearly the relation existing in this place between the foetal and the maternal portions. The not very thick layer of cells over the whole of the cotyledonal portion is remarkably expanded upon all its upper edge, and constitutes the thick ring, as I have said, of the tunnel (Plate IV., Fig. 1, p). This placental portion is formed by a minute web of foetal and maternal vessels ; these last appear- ing of a black color because they were injected in the preparation. The maternal vessels are everywhere surrounded by a somewhat thick layer of cells, rather larger than those I have described in the cotyledonal portion. In the midst of these cells, which are so close together as to form almost a compact mass, traverse the foetal vessels, which, in the figure, are seen empty and of a white color. The chorial tissue (9) is still adherent, in this inner and central part, to the placenta, as we have seen it attached to the sur- face of the cotyledonal portion, and over the whole foetal surface of the placenta (2). I have not been able to ascertain with certainty that the vessels of UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 205 the central part of the chorion, which are spread out in the cavity of the cotyledonal portion, communicate with the foetal vessels that traverse the placental portion ; rather has it seemed to me that the refluent blood of these two parts of the placenta mingles only in the cord before being carried to the foetus. In the rat, and more clearly in the cavia, appears the interesting fact of a two-fold anatomical constitu- tion in the placenta, which allows us to infer that in these animals the double office of the placenta, that of providing for the nutrition, and the respiration of the foetus, may be carried on separately in each part. In Plate IV., Fig. 2, is represented, highly magni- fied (500 diameters), a section of the aforesaid vascu- lar portion of the placenta of the cavia, as here are best seen the relations of its two fundamental parts. At a are indicated the injected maternal vessels, everywhere surrounded by a layer of cells (0). The empty foetal vessels (c) course in the midst of these, and it is only their thick trunks, at some points sur- rounded by abundant elements of the chorion (e), that came in contact with the elaborated placental cells surrounding the maternal vessels. The minute researches, which I have now ex- plained, in the anatomical structure and formation of the decidua and the placenta in certain rodents have clearly shown some facts which had hitherto escaped the investigations of the most careful observers, and which are of no small interest, because they suffice of themselves to prove beyond all question the error of two different classes of anatomists, namely, of those who maintained that the placenta is formed by the entrance of the villi of the chorion into the utricular 206 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. glands, and of those who taught, as has lately been the case, that it is developed by a tumefaction or some transformation of the elements preéxisting in the mucous membrane of the non-gravid uterus. But besides the complete elimination of the preceding er- rors, the facts demonstrated show with equal clear- ness that the decidua and the placenta are owing to a true and actual neo-formative process, so that put- ting my previous observations on this fundamental fact with those of even greater force now presented, the following conclusions appear to me warranted: (1.) That in many animals and in the human spe- cies it is not merely the epithelium of the uterine mucous membrane, and perhaps a subtile, sub-epithe- lial layer, which is detached and destroyed after con- ception, to give place to the neo-formative process that produces the decidua and the placenta, but in certain animals (as the rodents), in the segments of the horns of the uterus where the ova were arrested, it is the whole uterine mucous membrane, including the underlying vasculo-glandular layer, which is sub- jected to a uniform and complete destruction. (2.) That when there occurs so considerable a de- structive process of the uterine mucous membrane, and of all the subjacent parts as far as the muscular tissue, it is not established in a uniform way. It may be called simple when, as we saw in the rabbit, the process is limited to the entire separation and com- plete successive destruction of all the parts above mentioned. The same changes in these parts may be called compound when a neo-formative process is mingled with the destructive, as we have seen in the rat from the very beginning of conception. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 207 (3.) When the destructive process is simple, so too is the neo-formative process of the placenta which has its point of origin from vessels of new formation that issue from a portion of the uterine muscular tis- sue that is left denuded. When, on the other hand, it is compound, as has been observed in the rat, the neo-formative process of the placenta is clearly dis- tinguished into two phases. In the first is formed the uterine decidua which lines all the inner surface of the segment of the uterus where an ovum has been arrested. In the second the neo-formative proc- ess becomes active at one point only of the inner sur- face of the uterus, and it is there that the placenta is developed. The neo-formation of the first phase, so plainly recognizable in the rat by the shape and size of the cells, is what constitutes the decidua vera. (4.) In the place where the placenta is formed, the decidua is denominated serotina and reflexa. The peculiar structure of the decidua in the rat has shown us the existence of the serotina even at a somewhat advanced stage of placental development, and forming, as it were, a line of demarkation be- tween the glandular and vascular portions so distinct in the placenta of these animals. In complete devel- opment every trace of the cells of the decidua sero- tina is lost in the interior of the placenta, and re- mains only at the edge where the decidua is styled reflexa. In the rabbit the neo-formative process of the placenta is much more simple, and is primarily established only at one point immediately below the old detached uterme mucous membrane. Of this we have positive proof by observation of the mucous membrane with its crypts and the subjacent connect- 908 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. ive tissue as far as the muscular wall in course of de- struction above the placental neoplasm. These de- tached and altered parts form the deciduse vera and retlexa; there is thus wanting in the rabbit that first phase of the neo-formative process which we have so plainly seen in the rat, constituting the decidua vera, the serotina, and the reflexa. In the place where the placenta is formed, it may be thought that the development of the decidua serotina and the reflexa is the same in the neo-formative process of the placenta, but in the structure of the decidua vera the differences are very considerable between the two species of rodents; the decidua vera in the rat resulting from special cellulo-vascular elements entirely different from the elements of the old mucous membrane, and from those of new formation accom- panying the destructive process of the mucous mem- brane, whilst in the rabbit the new-formed elements constituting the decidua vera are altogether wanting. (5.) The placenta of the Cavia cobaya, like that of the rat, is plainly separable into two parts, but in the cavia that part which I have called glandular in the rat has a better defined form, analogous to the structure of a vaccine cotyledon, thus presenting, united in a single placenta, two unlike forms of this organ ; that of a ruminant in its central part, every- where encompassed by that lace-work of foetal and maternal vessels found throughout the whole extent of the single placentze, whether of zonarial or discoidal form. This anatomical peculiarity, so well marked in the cavia and observed, although less perfectly, in the rat, may serve to explain the two-fold nutritive and respiratory office of the placenta in the mammalia. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 209 Besides this remarkable peculiarity, the placenta of the cavia presents another, relating to the decidua reflexa, which has, in this animal, a special impor-’ tance, throughout the whole period of gestation, in the anatomical constitution of the placenta. The new-formed elements of the reflexa, in addition to the modifications and the important offices they sus- tain in the peduncle of the placenta, constitute also its external wall, maintaining a peculiar structure up to the close of pregnancy. Very recent observations have proved that the neo-formative process which produces the maternal portion of the placenta has its origin in vessels which, although in continuity with the uterine ves- sels, yet even in the placental neoplasm present al- together special characteristics, — either because the arterial as well as the venous vessels lose their exter- nal walls and thus the anatomical peculiarities which serve to distinguish them, and are formed by the en- dothelium alone (as Kolliker has indeed observed in the human species), or because from their external surface are generated the secretory cellular elements which have their proper characteristics and are inte- gral parts of the maternal or secretory portion of the placenta. The origin of these cellular elements has always been uncertain, but we have obtained its positive demonstration by examining the placenta of the rab- bit during its first stages of development, and the uterine portion of the decidua reflexa in the cavia when the placenta has attained its complete develop- ment. With the aid of injections this important ob- servation can be readily made in the formed placenta 14 210 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. of the dog, which is identical with that of the 1S So well described and illustrated by Turner. I have until now followed the old method of col- lecting new facts and particulars relative to the mani- fold initial forms of the placenta, as shown in the dif- ferent species of mammiferous animals, but I think the time has arrived for leaving the analysis, and for attempting the anatomical synthesis of the placental organ. The conclusions which I have presented relative to the complete destruction of the uterine mucous mem- brane, including all the underlying vasculo-glandular layer, at once appear in open and marked contradic- tion to facts positively ascertained, which show that the utricular glands of the non-gravid uterus not only remain but certainly increase in volume during the whole period of pregnancy. At first sight the contradiction is so plain and striking that one is in- clined to believe that the production of the decidua in cases of diffused, multiple, or single placenta, when the old uterine glands remain and increase in volume, must be necessarily owing to an anatomical process entirely different from that observed in certain ro- dents, in which, from the very beginning of concep- tion, the whole glandular DI is completely altered and destroyed. But I do not think I err in asserting that the dif- ferences indicated, which seem so important, are only differences in degree, and therefore more apparent than real, and that even the two extremes which these facts include, namely, the destruction of the epithe- lium only of the uterine mucous membrane after con- ception, as takes place in the human species, and the UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 211 destruction of a thick layer of the mucous membrane and of the uterine glands, as seen in certain rodents, help in their turn to prove to us that the laws gov- erning the neo-formative process of the decidua, when it exists, and of the placenta in all cases, are identical in all mammals, whatever may be the form assumed by the placenta. I shall not enter into a minute analysis of this subject, reviewing separately my preceding observations at length, but shall limit myself solely to some brief considerations which seem to me sufficient for my present purpose. In the case of diffused placenta, it 1s known that in its simplest form, described by me in the sow, and by Turner in Orca gladiator, every trace of the old epithelium of the uterme mucous membrane of the non-gravid uterus is entirely lost, and that a new epithelium of different form covers the small crypts of new formation in which are disposed the villi of the chorion. In the solipeds the shape of the new crypts or glandular follicles clothing all the inner sur- face of the gravid uterus is better defined and more complete than what was observed in the sow and the cetacea ; evidently, however, the new formation takes its origin immediately below the old epithelium of the uterine mucous membrane of the non-gravid uterus, wherefore, in all cases, the destructive process of the former elements of the mucous membrane cer- tainly affects in these animals the old epithelial layer throughout, and for the most part extends to the more superficial layer of the sub-mucous connective tissue. Over all the internal surface of the uterus thus laid bare takes place the neo-formative process, at first of cellular elements only, from which as preg- i 912 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. nancy advances develop the crypts or follicles that constitute the maternal portion of the placenta. In. animals having a diffused placenta a decidua vera does not exist, since it is all the neo-formed elements that, over the whole internal surface of the uterus, are transformed into the new glandular organ constitut- ing the maternal portion of the placenta; or, if you please, the decidua vera, in the case of diffused pla- centa, is represented by the old epithelium of the mucous membrane which is detached; as in the rab- bit the decidua vera is represented by all the ele- ments of the mucous membrane, by the layer of sub- mucous connective tissue, and the glands which are separated from the uterus after conception. In those mammals having a diffused placenta, as in certain rodents with a single placenta, the neo-formative process is always preceded by a de- structive metamorphosis of old elements of the mu- cous membrane of the non-gravid uterus, the only difference being that in diffused placenta the de- structive changes are confined to the epithelial layer that covers the uterine mucous membrane, and the neo-formative process is extended and completes it- self over the whole inner surface of the uterus; while, on the other hand, in cases of single placenta, the destructive process attacks extensively and more deeply the entire uterine mucous membrane; but the neo-formative process, uniform at first, is afterwards always limited and circumscribed to that point only of the uterine surface where the placenta is attached. The decidua vera is composed of the new elements that are arrested in their development when the first phase of the neo-formative process takes place, as we have seen with certainty in the rat. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 213 The multiple placenta which I have studied in the cow, in the sheep, and in the deer are developed only at certain fixed points of the inner surface of the ute- rus, namely, in the cotyledons of the non-gravid ute- rus, and it is at these places only that the destructive and superficial changes occur. The neo-formative process, by which the uterine cotyledon of the gravid uterus is produced, is also limited to these same points. In these cases, likewise, a decidua vera is not observed. It does not exist on the uterine surface unoccupied by the cotyledons, because in this exten- sive portion of the uterus the parts which constitute the mucous membrane remain intact; it is not found in the cotyledons, since at those places the active pro- liferation of cells from the walls of the neo-formed vessels constitutes the placentai masses or uterine cot- yledons, which have been regarded by many, and recently even by Kollker, as simple tumefactions of the uterine mucous membrane. In the case of multi- ple placenta, also, the neo-formation is preceded by a metamorphosis of some epithelial elements limited to certain places only of the uterine mucous mem- brane of the non-gravid uterus. In short, there oc- cur at circumscribed points of the internal surface of the uterus the same changes which we have seen taking place over the whole of that surface in ani- mals having a diffused placenta. Observations which I have made on the formation of the cotyledons in the cow seem admirably to con- firm what I have just stated. It is generally thought that in the cow, during pregnancy, the neo-formative process takes place exclusively in the circumscribed spaces known under the name of cotyledons of the * 914 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. non-gravid uterus, but whoever examines the gravid vaccine uterus will not seldom find in the midst of the large, normal cotyledons small ones scattered here and there, from the size of a grain of millet to that of a bean, or larger. The true signification of these small cotyledons was rendered plain to me by a beautiful anomaly noticed by Dr. Rossi, municipal veterinary surgeon. Ina gravid uterus of the cow, where the inner surface was covered with these small cotyledons, and in some parts so extensively as to appear diffused in the midst of the normal ones, the anatomical structure (size excepted), even with re- gard to the foetal portion, was the same in the small irregular and in the larger normal cotyledons. Now these facts, in my opinion, show that in the uterus of the cow, at the time of conception, the de- structive process of the epithelium is not always lim- ited to the spaces occupied by the cotyledons, but extends to some points of the remaining uterine mu- cous membrane, and that in the instance mentioned it was exceptionally extended to a great part of the inner surface of the uterus; also, that in the special condition of the uterus at the moment of conception the occurrence of the epithelial denudation is suffi- cient to establish the neo-formative process, or the development of small cotyledons even on that por- tion of the uterus where they would not be developed normally. Accidentally in the uterus of the cow may be formed cotyledons of the gravid uterus out- side of the places preéstablished by nature (cotyle- dons of the non-gravid uterus), which I have else- where shown takes place normally in the uterus of Cervus Porcinus. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 215 The observations mentioned, both the normal and anomalous, show that the establishing of the neo- plasm on the part of the mother is all that is needed in order that from the opposite side the foetal portion may be developed in the chorion; and the anomaly observed in the cow explains how in the normal state the foetal cotyledons are formed in the chorion only, and precisely in the places corresponding to the maternal cotyledons. In the carnivora, as in the quadrumana and in woman, the destructive process is equally superficial, and limited to the epithelial layer; but in the car- nivora, as in other multiparous animals, it is confined to those segments of the uterine horns where the ova have been arrested, while in the quadrumana and in the human species it affects the epithelium of the whole cavity of the uterus. In these cases the neo-formative process is deter- mined by the extent of destructive changes; that is, it is limited to the segments of the uterine horns where the ova are found, or, on the other hand, ex- tended to the whole inner surface of the uterus. The neo-formative process, which is established wherever the uterme surface is denuded of epithe- lium, gives rise to the formation known as decidua, and whether this becomes vera, reflexa, or serotina depends on the place where the ovum is arrested and where the placenta will be formed. In advanced pregnancy, or at its close, the decidua vera represents the first phase of the neo-formation, which was arrested in its development because the placenta was formed at another part of the uterus, since at the place where the placenta was formed: 916 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. there is proof that the first neo-formative process continues and completes the phases of its growth, , constituting the serotina. The activity of the first destructive process and of the subsequent neo-formative one that uniformly fol- lows in the segments of the horns of the uterus in the multiparous females, or over the whole internal surface of the uterus in the quadrumana and the hu- man species, may be estimated by the thickness of the decidua vera before this is detached from the in- ternal wall of the uterus, because it represents the two facts which I have indicated above. We have observed these changes with greater exactness in the gravid uterus of certain rodents where it is the whole mucous membrane and also the thick glandular layer that are altered and detached in the first phase of the destructive process; but in the human species and in the rodents that we have examined where the epithe- lial layer alone is separated, the decidua vera is rep- resented by the neo-formed cells and the elements of the mucous membrane that have been affected by the destructive process, or by the last alone, as we have seen in the rabbit. Although, indeed, in woman only the epithelial layer is separated, yet it is the innermost layer of the muscular tissue of the uterus that remains uncovered, as we have seen to be the case in the rat, in the rab- bit, and in the cavia; so that, notwithstanding the considerable differences we find with respect to the parts attacked by the destructive process, the change that takes place in the cavity of the uterus is identical in all cases: it is always the internal muscular tissue of the uterus that remains uncovered and denuded. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 217 In the human species, as in the rodents examined, after the separation of the decidua vera from the in- ner surface of the uterus and during the period of pregnancy, the internal muscular surface of the ute- rus is clothed with a uterine mucous membrane iden- tical with that with which it was provided before conception. In woman, the reproduction of the sim- ple epithelial layer, which by itself represents all the mucous membrane of the uterus, is all that is needed in order that the internal surface of the uterus should be restored to the primary normal state that preceded the pregnancy. In the rodents the regen- erative process is much more extensive; the epithe- hal layer is indeed the first to be formed in these animals; but to return to the primitive state there must be a development of the utricular glands, and a renewal of all the anatomical elements that are found in the sub-mucous connective layer which normally is superimposed on the uterine muscular tissue. These summary considerations sufficiently prove, as I think, that the changes which are established in the uterine mucous membrane immediately after con- ception, while varying in degree, in extent, in impor- tance, do not vary in their intimate nature, which consists in a primordial destructive process, more or less marked, of the uterine mucous membrane, which is indispensable for the beginning and completion of the neo-formative process, from which, in all cases, re- sults the development of the maternal portion of the placenta. The unity thus maintained amid so great diversity of the conditions which, so to speak, govern the formative process of the placenta in the different mammals helps now in our inquiry on the unity of 918 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. the anatomical type of the placenta in the mammalia and in the human species, in connection with the physiological unity that controls the nutrition of the foetus in all vertebrates. 168 It is a well-known fact that during the period of embryonic life, the vertebrate animals, to whatever class they belong, in order to complete the marvel- ous phases of their development, require a special nutriment, which is always furnished them by the mother, and this whether the embryonic life is per- fected apart from the body of its mother, in the in- terior of an egg, or, on the contrary, within, by a di- rect relation with the uterus of the mother. Indispensable, therefore, in all cases, for the nutri- tion and the development of the foetus in the verte- brate animals, are both the maternal aliment and the means by which it may be appropriated and con- verted into its own substance by the embryo; and however many and considerable may be the differ- ences met with in these two fundamental factors, the unity running through them readily appears under two general forms, represented by the yolk of the egg in the oviparous animals and by the placenta in vertebrate mammals. The only difference in these two facts, at first sight so dissimilar, consists in this: that the nutritive material for the embryo of the mammalia is furnished by the mother by means of a special organ, the placenta, which elaborates it by degrees, as the embryo is developed; whilst in the oviparous vertebrates, the maternal aliment is stored up in a mass by the mother, and emitted with the UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 219 egg in the quantity needed by the embryo to com- plete its growth. The means available to the embryo for appropriating the maternal aliment are always, in every case, furnished by its vascular appendages, which are destined to absorb and convey to the foetus the materials needed for development. Considering the question from this general point of view, the two fundamental parts which constitute the placenta of the mammifera, the maternal and the foetal, are also found in the oviparous vertebrates, and therefore, strictly speaking, a perfect placenta in its two basic divisions cannot be denied to these ver- tebrates, because the growth of the embryo, both of the mammiferous and of the oviparous animals, is governed by one and the same law, and the great diversity of the methods adopted by nature in the two is subordinate to the unity of the mode in which she accomplishes her purpose, namely, the nutrition of the embryo from the materials which are furnished by the mother. But, more than this, even anatom- ically, the connecting link between the oviparous ver- tebrates and the mammalia is not wanting. Huxley’ found that in certain fishes, especially in the vivipa- rous selachu of the genera Mustelus and Carcharias, there exists a sort of rudimental placenta, formed by introflexions or numerous folds of the uterine mucous membrane, corresponding with as many similar ones in the walls of the umbilical sac. I am not aware that this important observation has been repeated and carefully investigated by others, and shall there- fore give the results of my own studies; but I ought 1 Manuale dell’ Anatomia degli Animali vertebrati, page 125. Flor- ence, 1874. 220 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. to mention that analogous observations were long ago made, and have been recently confirmed by able and minute researches, which are too important to be omitted. As early as 1787 Cavolini’ stated that he had seen in a gravid torpedo (Raja torpedo L.) the embryo almost developed in the uterus, with the yolk still attached by means of the umbilical cord; but this yolk was fastened to the interior of the uterus by means of an infinite number of red papille, existing upon the uterine wall and clinging to the body of the yolk. I endeavored to repeat this observation, which would have been of special importance in ex- plaining this part of my work, because the papille or uterine villi indicated by Cavolini would represent in certain viviparous fishes the elementary typical form, which I shall show exists in the maternal por- tion of the placenta of the mammalia. But if the statements of Cavolini are verified upon examination only of the gravid uterus of a torpedo, there arises some doubt as to their importance when we compare the gravid with the non-gravid uterus of this fish, since the mucous membrane of the non-gravid uterus is likewise covered with an infinite number of villi, which, in volume, form, and the anatomical elements composing them, are identical with those observed in the gravid uterus. One sole difference is noted, which, however, explains the observation made by Cavolini, and this is, that while the mucous membrane ‘ of the non-gravid uterus of the torpedo is uniformly covered with a villous coat, in the gravid uterus, on the other hand, this is found accumulated at certain 1 Memoria sulla Generazione dei Pesci e dei Granchi. Naples, 1787. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 221 points, and restricted to these, considerable portions of the mucous membrane being destitute of villi, or showing but few, and those far apart from each other. Any doubts, however, that may arise when limiting the investigation to the uterus of the torpedo are completely dispelled when the observations are ex- tended to other fishes, as was done by Bruck in his important work, in which he not only quoted the re- searches made by J. Miller and Leydig on the dispo- sition of the folds of the mucous membrane and the presence of numerous and large villi in the gravid uterus of different species of selachii, but by accurate examinations of his own proved that these numerous villi are developed only after conception has taken place. | He considers* the uterine mucous membrane the most important part for study, because in the vivip- arous species it is the seat of interesting modifica- tions at the period of gestation. In the non-gravid uterus the mucous membrane is of a pale red color, very smooth, appearing more velvety near the poste- rior extremity. Before the ovum arrives in the uter- ine cavity, the epithelium that covers the mucous membrane proliferates and the velvet-like appearance is more evident, because the wall of the cavity ac- quires a plainly villous aspect. In Pteroplatea alta- vela, the villi are so numerous that the mucous membrane is entirely covered ; they are from one to two centimeters long, from one and a half to two cen- timeters wide, and are so close together and so inter- 1 Etudes sur l’ Appareil de la Génération chez les Sélaciens. Stras- burg, 1860. 2 Idem, p. 58, etc. = 992 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. twined in all directions as to form an inextricable mass, soft and pulpy. When the uterus incloses one or two foeti the villi are so long and so numerous that the young seem as if hidden in a vascular nest. When the villi are fewer in number they present an arrangement more or less regular; according to Ley- dig they are disposed in longitudinal rows, very regu- lar, in Scymnus lichia and in Acanthus vulgaris; but in order to observe these dispositions, it is necessary, Bruck tells us, ‘to study the uterine mucous mem- brane at the beginning of gestation, since at a later period the villi are so long and so involved that all regularity seems lost.” These villi are composed of the same anatomical elements that form a villus in any mucous membrane whatever, and according to the author are developed to form a vascular envelope for the young, in which they shall find the materials necessary for their growth and development. Through the courtesy of my esteemed friend, Pro- fessor Salvatore Trinchese, I was recently enabled to study the uterine horn or chamber of a Mustelus levis at the close of gestation, in which I found six per- fectly formed young. After several careful examina- tions there was clearly shown the singular fact, which I have not seen mentioned, that every foetus with its envelopes was included and perfectly inclosed be- tween two large folds of the uterine mucous mem- brane, which had established an epithelial adhesion by simple contact, very close at the edges and through- out their whole length. The external membrane of the ovum, completely anhistous, and in direct relation with the internal surface of the two folds forming the UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 223 completely closed external sac, was covered with a somewhat dense layer of mucus. The long umbilical cord terminated in an ample umbilical vesicle, and this at its extremity adhered strongly to an elevation of the uterine mucous membrane, oval in shape, and about acentimeter in diameter. The uterine mucous membrane as well as the umbilical vesicle was at this point very richly furnished with vessels. I did not observe upon the surface of the umbilical vesi- cle the vascular appendages mentioned by Huxley.’ This species of rudimental placenta is also found in- closed in the sac formed by the folds of the mucous membrane, and precisely at the lower angle made by them, as they project and comprise the whole ovum in their interior. Huxley had already taught that in the aforesaid species of mustelus, and in others of carcharias, there | was observed this sort of rudimental placenta, formed by the doubling of the walls of the umbilical sac and of the uterine mucous membrane; and this kind of in- troflexion, as I have been able to verify, really exists, is very close and complicated, and the superficies of contact between the epithelium of the umbilical vesi- cle and that of the uterine mucous membrane is there- fore by far more extensive than had been supposed. These observations made on certain viviparous fishes are, In my opinion, of no little interest, because they represent in the most simple and rudimental way the same forms which are found in the placenta of the mammalia. The contact of the uterine mucous membrane with the foetal envelopes which I have noticed in Mustelus l Op. cit., p. 32. 994 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. levis may perhaps have its counterpart in the pla- centa of the marsupialia; but assuredly the simplest forms of diffused placenta of certain mammals, with a much higher and more complex structure, find their counterpart in the elementary form indicated in Mus- telus levis, while, according to the observations of Bruck, in other viviparous fishes we have, as we shall see, the primordial type of the maternal portion of the more perfect and complicated placenta of mam- mals, and even of the human species. It is sufficient now to notice that a very important link between the oviparous and the mammiferous ani- mals is established, and that, in the most elementary or primordial forms of placenta which are met with in certain viviparous fishes, there are found clearly distinct the two fundamental parts of the placenta of the mammals, namely, the maternal and the foetal. Later we shall ascertain that even in these elementary forms the placenta preserves the anatomical type of the organ, which is observed in its highest develop- ment in different mammals and in the human species. The inaccurate and often erroneous opinions hith- erto held upon the structure of the placenta in mam- mals have not been limited to the field of anatomical or physiological science, but have embraced a much wider sphere, since able men like Owen and Huxley, and very lately Kolliker, have marked out funda- mental distinctions among the mammiferous verte- brates, drawn from the presence or absence of the pla- centa, or from the occurrence of certain facts in the act of parturition, joined with the general forms which the placenta assumes in the different orders of mam- malia. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 225 All know that so illustrious a scientist as Owen taught this distinction among the mammals: that there were those without a placenta (mammalia im- placentalia), and those possessing a placenta, which he called mammalia placentalia. Among the implacentalia Owen placed the marsu- pialia, and direct observations on the monotremia being wanting he inferred that they too should be assigned to the implacentalia. Recently Kolliker® has proposed to substitute the name of mammalia achoria for Owen’s implacentalia, and that of mammalia choriata instead of placentalia. In his opinion, many mammals which, according to Owen, are placentate, and by many are improperly described as having diffused placenta, have none, and he explains his idea by stating * that “in those animals incorrectly classified as having a diffused placenta, the chorion is covered with small villi, which penetrate into simple cavities of the uterme mucous membrane, from which they are easily removed; hence formations that may be regarded as analogous to a placenta are entirely wanting;” and, treating of the placenta of the ruminants, he remarks that in these animals? “ the villi of the chorion have many ramifications which dip down into spacious hollows of the tumefied uterine mucous membrane, and, moreover, the foetal and ma- ternal parts stand so related as to constitute numer- ous formations analogous to placenta.” According to Kolliker, then, not only would the marsupialia be implacentalia, and perhaps the mono- 1 Entwickelungsgeschichte des Menschen und der hoheren Thiere, page 352. Leipzig, 1876. 2 Ibidem, page 354. 8 Ibidem. 15 226 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. tremia, as was taught by Owen, but also the cetacea ; of the pachyderms, the elephant, the hyrax, the hog, and the solipeds; among the ruminants, the comel- ide, as well as the genus manis among the edentata, — all of them animals in which the two fundamental parts of the placenta have been of late, by Turner and myself, in their most important particulars, minutely described and illustrated by numerous figures. I do not know if, when he says that in ruminants the coty- ledons “ constitute formations analogous to placenta,” Kolliker believes that these animals are not really placentate, a point with regard to which doubt is no longer permissible. At all events, the subject is im- portant enough for us to inquire how a man so dis- tinguished in science was led into so grave errors. In order to ascertain the structure of the placenta, this illustrious histologist made the study of the human placenta the foundation of his researches, and owing to the great difficulties which are met with in its in- vestigation with the ordinary anatomical methods he fell, or rather he was drawn, into the error of assert- ing! “that it was merely for the convenience of de- scription that one designated the human placenta as maternal and foetal.” This imperfect knowledge of the two fundamental parts of the placenta led him into the further error of regarding as simple depressions or tumefactions of the uterine mucous membrane those parts which have been shown by Turner and myself to be glandular follicles of new formation, constituting the secretory organ or maternal portion of the pla- centa, clearly distinct from the foetal and absorbent portion, composed of the villiof the chorion. Turner, 1 Op. cit., p. 331. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 227 with great clearness, has arrived at this conclusion when he states! that no precise idea or exact concep- tion can be formed of the intimate structure of the placenta except by considering the two surfaces in their relation to each other, to wit, the maternal or secretory surface, and the foetal or absorbent. As a necessary consequence of error, many animals would be considered by Kolliker as without placenta, when their possession of it has been proved beyond doubt, and that it is formed by the two fundamental parts which are indispensable in all vertebrates for their nutrition and for the completion of their period of embryonic life. I claim indispensable, although the illustrious Owen, from personal observations, maintained that in the marsupialia the placenta is wanting, and it was precisely upon these observations of fact that he founded the great distinction of mammifera impla- centalia and placentalia. Elimmating the erroneous amplification which Kolliker sought to introduce into mammalia impla- centalia, there remains the distinction founded by Owen, which indeed rests upon a single observation that he made upon the uterus of a pregnant female of a gigantic kangaroo, or Macropus major. This celebrated anatomist declared that the foetus was wrapped in an external membrane, rather delicate and without vessels, which had the appearance of be- ing, and probably was, a serous membrane; that be- low this was the amnion; the umbilical vesicle was furnished with large omphalo-mesenteric vessels com- 1 Lectures on the Comparative Anatomy of the Placenta, page 114. Edinburgh, 1876. 228 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. municating with the vessels of the amnion, but there was no trace of the allantois or its vessels. It ought, however, to be added that Owen himself, when he had occasion to examine a young kangaroo that had descended a little way into the marsupion or mater- nal pouch, observed in it the urachus, which extended from the vesicle as far as the umbilicus, and in this only two umbilical arteries in the interior, without the corresponding veins. From these observations, he admitted that in the kangaroo, towards the end of intra-uterine life, may be formed a small allantois, but that there is no relation established by it be- tween mother and foetus. However great the respect I hold for so eminent a scientist, yet it cannot be denied that the very facts that he has advanced give rise to grave doubts as to the entire absence of the placenta in these animals — doubts necessarily resulting from his own observation of the presence of an umbilical cord, although it was formed only by two umbilical arteries. If the illustrious Turner had not confirmed my ob- servations on the maternal portion of the placenta in the sow and the mare, and had not extended them to the cetacea in his description of the placenta of Orca gladiator, I might feel some hesitation in men- tioning that, at the time when Owen examined the uterus of the kangaroo, my own studies and those of Turner were unknown; and also the important changes which the mucous membrane in these ani- mals undergoes at the beginning of gestation, to give rise to the neo-formative process of the maternal por- tion of the placenta had not been described. There- fore, the observations upon the embryo of the marsu- UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 229 pialia, which led Owen himself to infer that even in these animals, at the close of intra-uterine life, an al- lantois might be formed, gave grounds for the suppo- sition, from facts afterwards learned, that although in the marsupialia also (less completely and later, in- deed) there may take place upon the mucous mem- brane the formation of the maternal portion of the placenta, and villi may be formed upon that serous envelope which was without them at the period of gestation, when Owen made his observation, yet this neo-formative period of the two parts of the placenta may be more delayed, and consequently of shorter duration, in the marsupialia than it is in other mam- mals having diffused placenta; and the presence of the two umbilical arteries noticed by Owen in a young kangaroo that had descended into the mater- nal pouch considerably strengthens such an infer- ence. Perhaps the form of diffused placenta found in these animals may be more elementary and simple than even that observed in the hog, on account of the peculiarities attending birth in the former, and therefore not easily noticed in a first or single exami- nation. But the facts, so far as known, rather con- firm than weaken the deduction that also in the mar- supialia there exists a placenta composed of its two fundamental parts, namely, the maternal and the foe- tal; and until our knowledge on this point shall be clear and certain, we cannot admit that it has been proved that the ovum of the marsupialia does not re- ceive for its development nutrition from a placenta, which, as I have remarked, cannot, strictly speaking, be denied even to oviparous vertebrates, and of the 230 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. existence of which in certain viviparous fishes we have positive proof. But even allowing as indisputable the demonstra- tion that every kind of placenta is wanting in the marsupialia, they yet could not be styled implacen- tate, because there would still remain the funda- mental fact characteristic of the placental organ, . namely, the contact of two surfaces,—the foetal or absorbent, represented by a chorion without villi, and the maternal or secretory, represented by the uterine mucous membrane, which I have proved exists as a rudimentary form of the placenta in the Mustelus le- Vis. From my earliest observations on the different forms of placenta in certain mammals, I stated the reasons for my conviction that the fluid secreted by the utricular glands serves for the nutrition of the foetus at the beginning of embryonic life, in the pe- riod, that is, which precedes the development and the | vascularization of the villi of the chorion, and the for- mation of the crypts or glandular follicles in the case of diffused or multiple placentz, or of the maternal portion of the placenta where that organ is single un- der the zonarial or the discoidal form. Turner’ was induced to believe, from the consideration of the vas- cularization of the chorion even in the extended zones or areas of it which in certain animals are destitute of villi, while the utricular glands, which stand opposite in the uterine wall, are increased in volume, that the vessels of the chorion in these zones were the absorb- ents of the materials furnished by the utricular glands during the whole period of gestation. He was not, LIO pci puo UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 231 however, able to decide positively as to the special office of the glandular secretion in the nutrition of the foetus. In certain animals having a diffused placenta, as in the solipeds, and in others with a multiple placenta, like the sheep, the inference of Turner can in no wise be disputed. In the solipeds, especially, it has been shown that the lacteal fluid that bathes all the uter- ine surface of the chorion must result from a min- gling of the secretion of the utricular glands with that separated by the glandular follicles or crypts of new formation which constitute the maternal portion of ‘the placenta. But in the gravid uterus of the sow, where the placenta is diffused, in the mare and in the cow, where it is multiple, in the sheep, where it is pluri-cotyledonal, I observed and described some anatomical facts which seemed to certify that in the latest period of gestation, against the aperture of the utricular glands, were constantly formed certain ob- stacles which prevented the free flow between the uterine surface and the chorion of the fluid secreted by the utricular glands! From these observations it appeared to me reasonable to believe that the impor- tance of the secretion of the utricular glands for the nutrition of the foetus might, in some animals, be limited to the earliest periods of their embryonic life, while in others it might continue during the whole term of foetal life. An analogous contradiction is noticed in different animals having the placenta single, and which by 1 Previous to my observations, Burckhard, in his memoir entitled De Uteri Vaccini Fabbrica, had already noticed the formation of this. obstacle in the uterus of the cow. 932 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. recent observations, even, has been brought out in a somewhat important way. In the greater number of cases where the placenta is single and in the human species itself, by the ample openings which the utricular glands maintain into the decidua vera, the inference drawn by Turner cannot be disputed. But the examinations which I have made upon the formation of the decidua and the pla- centa in certain rodents, in which all the old uterine mucous membrane, including the sub-mucous vasculo- glandular layer, is very quickly and altogether de- stroyed, in order to give place to the neo-formation of the decidua and the placenta, do not allow the belief that in these animals the utricular glands by means of | their secretion have any importance in the nutrition of the foetus. This is especially true in these animals, since the whole uterine surface not occupied by the pla- centa, and which is below the decidua vera of new formation, is clothed with a simple epithelial layer, which by itself represents, during gestation, all the elements of the uterme mucous membrane, the glands, and the underlying vessels which existed on the inter- nal surface of the uterus previous to conception. These observations prove beyond all doubt, in my opinion, that the fluid secreted by the utricular glands is not indispensable for the growth of the embryo in the mammifera, and much less is it indispensable to it through the whole period of intra-uterine life. Notwithstanding this conclusion, the observations made and the inferences drawn by Turner and my- self clearly show that if in some animals the fluid secreted by the utricular glands does not serve for the nutrition of the foetus even in the beginning of UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 233 utero-gestation, yet in others it may in some manner aid in nourishing the foetus during the whole period of intra-uterine life, while in most animals it may be the sole aliment that the ovum, separated from the ovary, finds in the uterus of the mother, and which of itself suffices, for a longer or shorter time, for the nutrition and development of the embryo. This, as is evident, does not imply a very wide dissension between the eminent Turner and myself, but merely a different appreciation with regard to the time in which, in the greater number of instances, the secretion of the glands is necessary for the nu- trition of the foetus. The importance of their secre- tion in the early period of pregnancy, or in some cases during the whole time of gestation, is not affected, and can in no way be absolutely excluded by the new facts which I have observed in the rodents. Now, as all are aware, the embryonic phases which in the mammifera are accomplished in the maternal uterus, are in the marsupialia divided into two dis- tinct periods: that of intra-uterine gestation, which is very short, and the rather long period of marsupial gestation, which comprehends the latest phases of the embryonic and the first period of the extra-uterine foetal life of the other mammals. Therefore, in the marsupialia, during the short period of their intra- uterine life, the fluids secreted by the utricular glands may suffice for nutrition and development ; and from observations made on other mammiferous animals this may be held as probable, until positive proof to the contrary is given, which has not yet been done. At all events, the want of villi in the chorion, as well as the absence of the crypts or glandular follicles | 234. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. during gestation, is not sufficient ground for pro- nouncing the marsupialia without placenta. There. may be a difference of form, but not an absence of the placenta, its two fundamental parts, the ab- sorbent or foetal and the secretory or maternal, being distinctly represented. In short, in the marsupialia the secretion of the utricular glands is observed as ex- ceptional and fundamental, which in other mammals generally is transitory; and even though it remains of use through the whole term of pregnancy, it is still associated with a glandular organ of new formation which is invariably present. In the marsupialia, then, we have in a higher degree the repetition of the fact observed by me in the Mustelus levis. We cannot therefore now positively assert that this new organ in its most elementary form is wanting in the marsupialia, or that it is represented only by an increase in volume and secretion of the utricular glands, which has been shown to take place in the gravid uterus of these animals; but it may be that in both these ways there is found in the marsupialia the simplest form of placenta among mammals, joined with the simplest but relatively higher form of dif fused placenta seen and described by Turner in the cetacea, and by myself in the sow. As early as 1829 the illustrious Cuvier had noticed that the marsupialia constituted a separate class, par- allel with that of the mammifera, the insectivora, the rodentia, the carnivora, the ruminantia, and the quad- rumana all meeting in it. The opinion of Cuvier, confirmed afterwards by the discoveries of Owen and | others in fossil marsupialia, would acquire a fine it demonstration should it be proved that the foeti of UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 235 the marsupialia have a large umbilical vesicle, from ‘which vessels extend to the chorion, which is folded. Who does not perceive the importance of such an observation, when placed beside those recorded above, on the most elementary forms of placenta found in certain fishes, in which the foetal nutritive vessels originate from the umbilical vesicle, and not from the allantois? The marsupialia would constitute a dis- tinct class, as Cuvier taught, which by its mode of placental formation would be the connecting link be- tween the viviparous fishes and the mammalia. But it is not in the marsupialia, where our knowl- edge of the placenta is so scanty and uncertain, nor in the monotremia, about which information is alto- gether wanting, that we are to look for the unity of the anatomical type of the placenta; such inquiry, to be useful, must be directed to those mammals in which the existence of the placenta cannot be doubted, whether diffused, multiple, or single, with either a zonarial or a discoidal form. . To these three principal forms of placenta corre- spond three fundamental facts, belonging to its ana- tomical structure, which may be divided into two general classes. In the first may be placed all the forms of placenta in which the glandular structure of the maternal portion is plainly evident; in the sec- ond those in which the glandular structure is obscure. The first division comprises diffused and multiple placentze : diffused, when the glandular organ of new formation takes the form of crypts, or of simple gland- ular follicles; multiple, when it assumes that of a 1 Huxley: Manuale dell’ Anatomia degli Animali vertebrati, page 337. Florence, 1874. 236 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. compound glandular organ. In the second division, the glandular structure of the maternal portion of the placenta is concealed, as in all cases of single pla- centa, from the fact that the vascular or absorbent portion of the placenta is in direct connection with the cells that constitute its maternal, glandular, or secretory portion. The close relation in these cases of the two parts of the placenta has been the only obstacle met with in forming an exact idea of its in- timate structure. The observations which I have made upon the in- timate structure of the placenta of the Cavia cobaya have proved that even in cases of single placenta there may be found united in one animal the visible glandular form and the hidden in the maternal por- tion of the placenta; and this union of two forms so different in one placenta has seemed to me to possess a certain importance, as showing in close relation what we have believed most dissimilar. Professor Turner, in his important work,’ came to the conclusion, elsewhere pointed out by me, that to form an exact idea of the anatomical structure of the placenta two surfaces are to be considered, — the foetal or absorbent, and the maternal or secretory (or, as I have named it, glandular). This funda- mental fact can no longer be regarded in any degree doubtful, but, formulated in so general a manner, this idea of Turner’s cannot be applied with certainty to explain the manifold differences met with in studying the anatomical structure of the placenta in animals and in the human species. 1 Lectures on the Comparative Anatomy of the Placenta, page 114. Edinburgh, 1876. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 237 Comparing the observations which I have been able to institute with those very carefully made by Tur- ner on many other animals, I think I have arrived at an ultimate conclusion, and have been able, in the midst of the manifold and striking differences pre- sented by the diverse forms of placenta in the mam- mals, man included, to fix upon a typical and funda- mental anatomical form of placenta, common to all. If I have demonstrated the truth in this new deduc- tion, which formulates anatomically the physiological notion accepted and learnedly illustrated by Turner, a somewhat singular consideration will be presented. Hitherto, the ablest anatomists, as we know, have been confused by the diverse structural appearances seen in the placenta of the various classes of mam- mals, and the differences seemed so wide and so im- portant as to mislead the most learned scientists.! Keeping in mind this fundamental anatomical unity, on the contrary, it will no longer be the remarkable differences that command attention, but we shall be impressed and surprised that with the few and simple means adopted by nature there should be so great a variety and multiplicity of forms as to conceal until now the unity of anatomical structure of the placen- tal organ. Leaving for the present the question relative to the formation of the placenta in the marsupialia and the monotremia, for the solution of which data and exact observations are wanting, although, as I have previ- ously remarked, the idea of contact of the secretory and the absorbent surfaces may furnish an accurate 1 See Kolliker: Entwickelungsgeschichte des Menschen und der hòhe- ren Thiere, page 352. Leipzig, 1876. 938 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. conception of its structure in those animals, we have for consideration all the clearly determined forms of placenta known to us, from the simplest, which is the diffused placenta in the sow, to the most complex, the single and discoidal in the quadrumana and in the human species. The typical anatomical form which I have noticed in the two fundamental parts of the placenta, what- ever may be the outer appearance, is identical in all cases: it is that of a villus of new formation, both in the maternal and in the foetal part, composed of an internal vascular loop, surrounded by protoplasm, which is furnished with an outer epithelium. The office only of the two villi is different, the foetal one serving for absorption and the maternal one for secre- tion. The two villi always come in contact with each other. This contact may be more or less intimate, but the walls of the two vascular loops never, in any instance, touch; and this is the most important fact, because it invalidates the ideas hitherto held as to the mode of nutrition of the foetus in the uterus. In the case of diffused and of pluri-cotyledonous or multiple placenta, the secretory epithelium that covers the vascular loop of the maternal villus is found separated, and only in simple contact with the absorbent epithe- lium of the foetal villus, and this is why in placenta of these kinds the appearance of a glandular organ plainly results. According to the different ways in which the secretory villi are united or distributed upon the internal surface of the uterus are consti- tuted the crypts or the glandular follicles, both simple and complex, which have been described by Turner | UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 239 and myself, and which Kélliker! even now regards as multilocular depressions or tumefactions of the uterine mucous membrane, into which the foetal villi enter. In cases of single placenta, whether of zonarial or discoidal form, the glandular character of the organ, as a whole, remains concealed, as I have stated, be- cause the relation between the two species of villi are very closely maintained. Although the epithelium of the maternal secretory villus is always present, that of the absorbent villus is wanting, on account of the intimate relation between the two villi; the vascular walls of the foetal loop can of themselves better fulfill their office of absorption by tenaciously adhering to the secretory epithelium which clothes the maternal villus. Accepting the idea of the typical and single form of the two fundamental parts constituting the placenta, it is readily perceived that all the manifold and apparently essential differences in the very simple structure of the two villi that are met with in exam- ining the diverse forms of placenta in the mammalia depend upon three factors only. These factors may be thus specified : — (1.) The manner, as has been stated, in which there is established either an intimate relation, or else merely a simple contact, between the two villi consti- tuting the two fundamental parts of the placenta. (2.) The absence, as I have shown, of the epithelium in the vascular loop of the foetal or absorbent villus, because of the intimate relation which is established, in cases of single placenta, between the vascular loop of the absorbent or foetal villus and the secretory epi- 1 Op cit., p. 363, 364. 940 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. thelium, which is never wanting, in the vascular loop of the maternal villus. (3.) Finally, on the form of the vascular loop in the interior of the maternal villus, which may maintain the usual regular diameter throughout its whole course, or may, on the other hand, offer dilatations or ectasize, which in the placentz of the quadrumana and the human species are actually enormous. A minute comparison of the condition of the three above-mentioned factors in the different forms of pla- cente hitherto known and described would require too much labor, and too much repetition of what I have heretofore had occasion to mention. But, as I am anxious to prove as well as I can the truth and the simplicity of what has been asserted, I have placed together in the two divisions of Plate V. the diagrams of the different forms of placenta observed. This seems to me the most suitable way of explaining and demonstrating the unity of the anatomical type in all the various forms of placenta, and of showing that all the striking differences met with depend solely on the three simple factors which I have just pointed out. In the upper division, A, I have represented the plans of the diffused and the multi-cotyledonous placenta ; and in the lower, B, the single zonarial or discoidal, including the human placenta. The drawings in both exhibit a complete perpendicular section of the uterus, and of the two fundamental parts constituting the pla- -centa; the letters in small type show the same parts in the two divisions; the numerals serve to indicate the plan of that form of placenta intended to be rep- resented. Thus, at a are represented the walls of the uterus, % UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 241 whatever may be the form of placenta drawn in dia- gram above. I have omitted any representation of the utricular glands, because they vary in condition, and, as we have seen, are either completely destroyed before the placenta is developed, or all remain, acquir- ing a greater volume in cases of diffused and multiple placenta, or they remain and augment in volume over all the surface of the uterus except the place where the placenta is formed. In this place, when it is single, they are altered and changed in shape, form- ing in woman that species of trabecula with large in- terstices which is met with between the inner wall of the uterus and the uterine surface of the placenta. At 6 is indicated the layer of cells forming in all cases the basis of the uterine surface of the placenta, or the old cells of the decidua serotina in the human species. At c is shown the innermost layer of the rich vas- cular net-work formed by the uterine vessels, so greatly increased in volume in the gravid uterus. At d are indicated the placental vessels, properly so called ; their relation will be shown when we come to explain the plan of the single placenta. At e is represented that layer of cells which every- where invests the placental vessels in all forms of the placenta. These are the parts which are situated upon the internal surface of the gravid uterus, and are in relation with the foetal portion of the placenta. The chorion is indicated at f; at g are the vessels that traverse the chorion in order to form the um- bilical cord; and, lastly, at 2 are shown the vessels of the foetal villi of the chorion itself. Coming now to the different forms of placenta, the 16 a: 942 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. numeral 1, of division A, represents the fundamental typical form of the foetal portion of. the placenta, consisting of a vascular loop communicating with the vessels of the chorion, and covered with its absorbent epithelium. At 2 is seen the typical form of the ma- ternal portion, similar to No. 1 except that the vascu- lar loop is in direct relation with the uterine vessels, and the external epithelium that clothes it is in di- rect continuity with the cells of the serotina. We thus notice that, while preserving the typical form in the two villi indicated, there may be obtained, by means of the three simple factors mentioned, the most varied forms of placenta, — from the simple and diffused, which has been observed in the sow, to the most compound and complicated, as seen in the quad- rumana and in the human species. Nos. 3-4 repre- sent the plan of the simplest form of diffused pla- centa, minutely described elsewhere in the sow; 3, the foetal portion of the placenta in this ‘animal, which does not differ from the first division of the diagram ; 4, an exact plan of the maternal portion of the placenta in the sow, which is formed by the villi, regularly arranged, constituting numerous folds of the uterine mucous membrane, in the depressions of which the villi of the chorion are inclosed. Carry- ing the loop or foetal villus of No. 3 between the two maternal villi, No. 4, we have the precise plan of a vertical section of the placenta of the sow, and of the cetacea, as was shown by Turner in the Orca gladiator. At 5-6 we have the plan of the diffused placenta of the mare; 5 indicates the foetal portion. The absorbent villi do not deviate from the typical form in No. 1, except that instead of being isolated UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 243 they are numerous, and joined together in a sort of tuft. In the maternal portion, No. 6, the secretory villi are also united, so as to constitute calyces or follicles, for receiving the loops of the tuft made by the villi of the absorbent or foetal portion. From these calyces, formed by the secretory or maternal portion, and diffused over the whole internal surface of the uterus, there results a sort of layer, composed of so many crypts or glandular follicles of new for- mation, each of which receives within it a villus of the foetal portion. Nos. 7-8 represent the plan of a multi-cotyledonal or multiple placenta, particularly that of the cow, — which is more complicated in form than that of the mare, but which yet presents the identical structure in both the foetal and the mater- nal portions. The glandular follicles, No. 8, are not simple, but compound, and the foetal villi have an ar- borescent form instead of a simple tuft, as m the mare. The peculiarities of structure which I found and de- scribed in the placenta of the sheep, and of Cervus axis and porcinus, still remain plainly included in the diagram, although in these animals considerable dif ferences might be observed on comparison with the placenta of the cow. The fundamental typical form of the two villi seems to me clearly confirmed in the placente having a diffused form, and in those which are multiple or multi-cotyledonal. It is only the ideal unity which is wanting and must necessarily be wanting, since this unity results from analyzing into their elements the facts that determine the forms of placenta exam- ined. | In all these forms the relation of proximity is evi- 944 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. dent, and of simple contact of the epithelium of the absorbent villus with the fluid furnished by the ma- ternal villus, which assumes the form of a secretory organ. Although the typical form of the foetal or absorbent villi is maintained distinct and clear in all cases, the form of the secretory villus is not on that account lost in the modifications assumed by the se- cretory or maternal portion of the placenta in the different species of animals which we have hitherto examined. In fact, in the sow and the cetacea (dia- gram 3-4) we have only a repetition, or an increase in number, of the typical villi in the foetal as well as in the maternal portion. In a higher degree of de- velopment of this same form of placenta, that of the solipeds (Nos. 5-6), we find, besides an increase in number, an increase also of volume, in the two sets of typical villi, and the union of many maternal villi no longer gives rise to the appearance of small crypts, as in the former case, but rather to that of simple glandular follicles. In the ruminants (Nos. 7-8), besides number and volume, there is a subdivision and ramification of the villi in place of the form hitherto under consideration, and therefore the form in the maternal portion is that of a compound glandular follicle. In all cases, how- ever, the typical or primordial form of the two parts constituting the placenta is easily discernible. Ap- parently of far more importance are the differences in the examples of single placenta which I have arranged in the second division, B. In all these placente the fundamental characteristic is that the epithelium of the foetal villus disappears, in order that the walls of the vascular loop may come UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 245 in direct contact with the secreting epithelium of the maternal villus, which is never wanting. This fact is represented in its simplest form in diagram Nos. 9-10. In the figure, the vascular loop of the foetal villus, No. 9, appears slightly apart from the epithelium of the maternal villus, for the sake of avoiding confusion. In fact, however, many single placente in different mammals appear to be formed only of a complicated web of maternal and foetal vessels, which are always separated from each other by a cellular layer belong- ing to the maternal vessels. Now, in order that the diagram should be exact, the wall of the vessel of the foetal villus, No. 9, ought to touch and adhere to the epithelium of the maternal villus, No. 10. Fig. 2, of Plate IV., which represents a section of the vascular portions of the placenta of the Cavia cobaya, shows the exact copy of a transverse section of the plan of placenta, figured at Nos. 9-10, as it is actually ob- served also in the placenta of other animals. Nos. 11 —12 give the plan of the placenta in the dog, of which I treated in the first part of this work. Accu- rate drawings of this may be seen in Plate I, Figs. 2 and 3. This form of placenta, common to different ‘carnivora, and which Turner has accurately described in the fox, 1s very well suited for demonstrating that the secretory epithelium, or the cells of the placental decidua, are elaborated from the walls of the maternal vessels, because the maternal portion of the placenta is formed, as I have said, of a large-meshed net-work of vasculo-cellular tissue (Plate I., Fig. 2). The course of the vessels is more or less winding in the placenta of different animals, and the sinuosity varies, also, ac- cording to the period of gestation, being greater or 946 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. more frequent when the placenta has perfected its development. In the diagram I represent at No. 12 the mater- nal portions, and the aforesaid net-work is reduced to two simple vasculo-cellular columns (d, e). In these forms of placenta, the vessels of the foetal villi ramify into a rich and minute vascular netting, which is dis- tributed upon the cellular envelope that surrounds the vessels of the maternal villus. This relation be- tween the two portions of the placenta, which is ac- curately shown in Plate I., Fig. 3, is very simply exhibited in diagram No. 11, h indicating the rich capillary net, with only three branches for each trunk of the foetal vessel. On comparing this with the pre- ceding division of the diagram it is plainly seen that there is only a change in the mode of distribution of the foetal vessels, and that also the fundamental fact, namely, of the vessel of the foetal villus, without epithelium in contact with the epithelium of the ma- ternal villus, remains unaltered in these forms of pla- centa. Moreover in all single placentze, whether they have a zonarial or a discoidal form (from which results the concealment of the glandular character in the mater- nal portion), another fact, exceptional, inasmuch as it is observed only in the placenta of the quadrumana and the human species, is the ectasia of the vascular loop of the maternal villus. This constitutes one of the few modifications to be seen in the typical villi, and which has been the cause of the greatest and most serious difficulties hitherto met with in ascer-. taining the intimate structure of the human placenta. In the fox Turner observed and described some UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 247 dilatations in the maternal vessels,’ and with Eschricht looked upon them as a first intimation of the large lacune which are seen in the human placenta, and which I have also represented in that of the quadru- mana. When describing the placenta of the Cavia cobaya I exhibited a beautiful net-work of ectasic capillary vessels, underlying the cotyledonous portion of the placenta in that animal. (Plate IV., Fig. 1, n, and Fig. 3, a.) That the lacune in the human pla- centa and the quadrumana were only enormous dila- tations of the placental vessels I had already pointed out in my previous works, but the whole truth had not presented itself to me, because I had not been able to obtain positive Knowledge that the cells of the decidua were elaborated from the walls of the ma- ternal vessels. Comparative anatomy has now very clearly demonstrated this. As we know, the illustrious Waldeyer referred the cells of the serotina to the group called by him plasmatic cells, having their origin from the connect- ive cells, and being in intimate relations with the ‘vessels. My own observations lead to the belief that the cells of the decidua are rather a perivascular cel- lular tissue. The exact knowledge of this anatomical truth has a much greater importance than might at first ap- pear. This I will now show by means of a diagram altogether imaginary, but which will presently find direct application when we inquire into the structure | of the human placenta. This ideal figure is shown at Nos. 13-14, which is the same as the preceding diagram of the placenta of the dog, Nos. 11-12, with LKOpwcit.:pygo, and Bl.) Rig. W 948 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. the addition of the imagined ectasis of the vessel of the maternal villus, which is represented in an incip- ient state on the left of the figure, — whilst on the right, the dilatation has reached its last stage of de- velopment. At the left the incipient and irregular ectasis of the maternal vessel has not yet carried the secretory epithelium with which it is clothed (e) into contact with the walls of the vessel of the foetal villi (h). At the right, on the contrary, this has taken place, as we plainly see it must, from the continued dilatation of the maternal vessel. Now simply looking at this right side of the figure three things appear as truths, which are, in reality, only deceptive appearances. ‘The first is, that instead of the primitive vessel there is formed a lacuna of blood (d), while it is only a real ectasis. The second deception is that the foetal villi (e) are furnished with a proper epithelium, while it is only the epithelium of the maternal vessel that has come in contact with them. And finally the third, that the foetal villi float in the blood of the lacuna, whereas they are always separated from it, by the wall of the maternal vessel and by the epithelium round it. Setting aside the deceptive appearances, it is evident that the relation between the absorbent foetal villi and the epithelium of the secretory villus is identical with that noticed in plans 9-10 and 11-12, the only difference con- sisting in the ectasia of the vessel of the maternal villus. Finally, at Nos. 15-16 is represented in dia- gram the human placenta. At first sight we per- ceive, on the right of the figure, that the phenomena apparent in the diagram designed upon the plan of the placenta of the dog are also met with in the plan UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 249 of the human placenta ; but the truth cannot be held as demonstrated, even by an exact resemblance, which in reality rests upon an imaginary induction, and in treating of the human placenta this point deserves to be more minutely studied. It is known that, in the earliest period of preg- nancy, the placenta in the human species is repre- sented by a layer formed of a rather compact cellu- lar mass, called decidua serotina or placental decidua, in the midst of which runs a rich net-work of capil- lary vessels. From the surface of the chorion which is in contact with this, villi are formed, at first sim- ple, which penetrate among the cells of the serotina. For a time the relation between these two parts of the placenta is not so close that they cannot be sepa- rated. It is known, moreover, that with the prog- ress of the development, the vessels of the primary capillary net become ectasic and the primary simple villi proliferate and become arborescent. If we could loosen and skillfully separate without tearing the compact mass formed by the cells of the decidua serotina (the placenta cells) before the vessels become ectasic, we should obtain exactly what com- parative anatomy has very clearly shown us in the single placenta of certain animals, especially that of the dog, namely, a large-meshed netting of placental vessels, everywhere surrounded by a cellular layer, or the cells of the decidua serotina. The villi of the chorion which in the early period of develop- ment were, as we know, in contact with those cells, although they have penetrated into the serotina, would, if this were disentangled, be found actually in contact with the cellular envelope that clothes the 250 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. vessels of the capillary net-work, and there would at once be repeated precisely what I have represented in diagram, at Nos. 9-10, which corresponds to the actual structure observed in the placenta of the cavia, as drawn from nature, in Plate IV., Fig. 2. It was long ago known that, with the progress of development, the foetal villi in the placenta of woman proliferate and become arborescent, and that, on the other hand, the net-work of the maternal vessels di- lates and becomes ectasic. On this point the emi- nent Charles Robin taught’ that, “in proportion as the villi of the chorion increase in volume, and are sub-divided, the superficial capillaries of the placenta are largely dilated and form delicate vascular folds interposed between the villi, which are still short, and in contact with the chorion as far as their peduncle, and that as the villi of the chorion multiply their di- visions, so the interposed capillaries increase their dila-. tations.” It results from this double series of facts, so well described by Robin, that in a compact mass, like that of the decidua serotina or placental, the new branches proliferating from the primitive villi are necessarily forced against the cells of the decidua and the walls of the maternal vessels. With the increase in number and volume, the cells and the walls of the vessels to which they adhere are introflected in the cavity which is formed in these vessels by their dila- tation. This afterwards, in the complete develop- ment of the placenta, appears in lacunose form, but by the process now indicated the villus remains al- 1 Mémoire sur les Modifications de la Muqueuse uterine pendant et apres la Grossesse. Paris, 1861. Mémoire sur la Structure intime de la Vésicule ombilicale et de 1° Allantoide chez l’Embrion humain. Idem. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 251 ways covered and in contact with the layer of parietal cells that primarily clothed the maternal vessel. I have pointed out the succession of these facts at (0) No. 15 in the diagram. In the human species when the placenta has been fully formed there is not the least trace of the primi- tive net-work of the maternal vessels, and the large arborescent masses of the foetal villi may be said to swim in the maternal blood in so many compartments called cotyledonous cavities. For this reason Kolli- ker says! that if we imagine the chorion and all the villi taken away and only the uterine portion and the septa of the cotyledons left, the maternal placenta would have almost the appearance of a bee-hive. Two of these cavities, or two actual cotyledons, are drawn in diagram at C (Nos. 15-16), indicating the formative beginning of a cotyledon, D a cotyledon in complete development. In this last, the envelopes of the parietal cells of the ectasic vessel have been forced against the chorion, to which they adhere, thus constituting the lamina of the sub-chorial decidua ‘(é). The closeness and the union of the cells of the walls of two or more neighboring ectasic vessels form the septa of the cotyledons (7). The apertures or perforations in the septa which place in com- munication the blood of two so-called lacune, and the observations of Virchow, Kirvisch, and many others, who have seen the arteries communicate di- rectly with the veins in the interior of the placenta by means of large openings, attest the permanence of that original vascular net-work, every trace of which 1 Entwickelunssgeschichte des Menschen und der héheren Thiere, page 337. Leipzig, 1876. 252 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. has been supposed to be lost in the fully developed placenta, which does remain, however, deformed by the extraordinary ectasia it has undergone, and by © the introflexion of its own walls determined by the proliferation of the villi. Hence it is an illusion that the foetal villi float in the maternal blood, as it is an illusion that the epithelium that covers them apper- tains to the foetus. Recent observations do not materially change my former opinion, when, with Schroeder van der Kolk, I believed the cellular envelope of the foetal villi to be furnished them by the maternal portion, and not to be their own epithelium, as is even now asserted by Kolliker.! At the beginning of the development of the placenta in woman, the villi have their own proper epithelium, which remains to them as long as they preserve a simple relation of contact with the cells of the decidua, but which they lose when the relation is intimately established in the manner before pointed out, and as we have seen it take place in cases of single placenta in all the mammalia. In short, in the epi- thelium of the villi of the human species we observe that to take place successively which is seen as sepa- rate and permanent in the different placenta of the mammiferous animals. The epithelium is preserved so long as there exists a simple relation of contact be- tween the maternal and the foetal portion, and is lost when the relation becomes intimate; and it is sin- gular that no anatomist had noticed the considera- ble differences which exist between the epithelium of the primitive villi and that supposed by them to clothe the villi when the placenta has completed its 1 Op. cit., p. 333. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 253 development, and when they describe the villi as swimming in the maternal blood. The relation of the foetal villus without epithelium to the secretory epithelium of the maternal villus is maintained in the human species also, thereby con- firming the physiological idea elsewhere mentioned by me relative to the nutritive process of the human foetus in the uterus of the mother. Late observa- tions change nothing except the interpretation given as to the manner in which the cells of the decidua come in contact with the foetal villi; and without the proofs now drawn from comparative anatomy regard- ing the origin of the cells of the decidua, the com- pact mass formed by them appeared to show that they took their origin from the connective elements of the uterus and were gradually transformed. With this conviction it was natural to believe that by means of the simple ectasia of the vessels the cells of the decidua might be carried over against the villi and enwrap them. The crowded and compact mass of the cells of the placental decidua, traversed by a net-work of capil- laries, completely obscured the perception of their origin from the walls of the placental vessels, a fact which comparative anatomy has to-day clearly estab- lished. Without knowing this, there was not, and there could not be, any knowledge of the exact struct- ure of the human placenta, which, I think, may now be obtained with some simplicity and much clearness by adding what has been learned concerning this origin of the cells to the facts already possessed about the ectasic process that invades the net-work of the capillaries of the decidua serotina and placenta, and 954 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. the proliferation at a determinate point and area of a single stem, or of a simple villus that becomes an ar- borescent trunk. Without knowledge of these things, and before as- certaining the constant fact of the relation that is es- tablished between the foetal villus and the cellular envelope that clothes the vessels of the maternal vil- lus when the placenta is single, the genetic process of the human placenta could not be understood. It never was suspected, and the illusive appearances of the villi swimming in the maternal blood, and pos- sessing an epithelium of their own, were held as dem- onstrated facts. it should, however, be mentioned that Robin, as early as 1861, had noticed the analogy existing in the relations between the maternal and the foetal por- tions in the first periods of development of the pla- centa in the human species with those permanently established in the placenta of certain mammals. I hope it will meet the approval of that eminent scien- tist if, following the way luminously marked out by him, I have succeeded in proving that those first re- lations in the placenta of woman do not change even when the placenta has completed its internal devel- opment, but are identical with those met with in the single placenta of all the mammalia. This knowledge also explains certain conditions really existent and observable in the interior of the placenta, but which had no reasonable interpretation. ‘I have shown that, reducing to its most elementary 1 Mémoire sur la Structure intime de la Vésicule ombilicale et de |’ Al- lantoide chez l’Embrion humain, dans le Journal de la Physiologie de l’Homme et des Animaux, page 334. Paris, 1861. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 255 simplicity the intimate structure of a cotyledon of the human placenta, and to a single maternal vessel the vascular net that passes among the cells of the sero- tina, it must necessarily happen, by the very fact of the ectasia alone, that the decidual cells clothing the apex of the vessel should be carried against the cho- rion (Plate V., Nos. 15, 16, 2); that these, placed along its longitudinal axis, must come in contact with corresponding ones in the neighboring vessels (J) forming the so-called septa, and that at length, the ectasia having become much more considerable, the cells placed at the base of the vessel must be carried over upon the uterine surface. Not aware of these very simple facts, Winkler imagined the existence of a species of decidual leaves or lamine within the pla- centa. He gave the name of leaf or lamina of closure (schlussplatte) to the layer of cells found under the chorion, and that of fundamental lamina or leaf (ba- salplatte) to the layer of cells touching the uterus, and Kélliker* accepts these useless distinctions, but wishes to call the first one decidua placentalis sub-cho- rialis, and the other decidua placentalis sensu stricti- Ont. Nor are these imaginary leaves or lamine enough. Some trunks of villi reach from the chorion to the uterine surface and there necessarily the wall of the _ maternal vessel is doubled and placed in contact with the cellular envelope of the vascular net, which is in direct relation with the uterine surface (m), and at this point there results a kind of collection of placen- tal cells, which I described in my first work on the placenta in 1868, in order to show that the placental l Op. cit., p. 887. 256 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. cells were continued over the villi. Two years later, this same observation was repeated by Langhaus! and lately Kolliker ® attributes to him the merit of this discovery, which he judged interesting because he thinks it proves that the union of the two parts of the placenta is much more intimate than had hith- erto been believed! and he proposes to call these ex- tremities of the villi by the special name of roots of attachment (haftwurzeln).° In the places where, through the ectasia of the maternal vessels, their walls come into a strict relation of contact, are formed by this alone, as I have stated, the so-called septa of the cotyledons, which Kolliker manages to divide into two layers,* and the apertures which are observed in these, and, as 1s believed, place in communication the blood of the alleged lacune, remain to represent the old capillary net-work of the primitive decidua. It is only by insisting upon the mode of forma- tion heretofore indicated that we can acquire exact knowledge of the intimate structure of the human placenta, and correct the fundamental errors hitherto prevailing that the villi possess a proper epithelium, and that they swim freely in the maternal blood by the formation of the lacune. From what has been demonstrated we must conclude that in the human species, as in all the mammals where the placenta is single, whether it be of zonarial or discoidal form, the foetal villus without a proper epithelium, or having lost it, if there were such, at an early period of devel- 1 Zur Kentniss der menschlichen Placenta, Centralblatt, No. 30, 1870. 2 Op. cit., p. 336. 3 Op. cit., p. 333. * Op. cit., p. 336. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 257 opment, as is the case in woman, always comes in direct contact with the secretory epithelium which clothes the maternal villus. It is therefore only the introflexion of the walls of the maternal vessels upon the villi, and their enormous dilatation, that consti- tutes in certain quadrumana, and in the human spe- cies, a difference of form, though none of intimate structure, between their placentz and those of all the mammalia having the placenta single. It is well known that the ablest anatomists, among ‘ whom I may name Hunter, Bischoff, Weber, and Esch- richt, not to mention others referred to in my first work on the placenta, were perplexed by the fact of the presence of the foetal villi in the midst of the maternal blood contained in the lacune. Kolliker, not finding any of the opinions previously taught tenable, has recently made the assertion’ “that the presence of the free villi within the maternal vessels can in no other way take place than by the increase of the tufts of the foetal villi; the neighboring por- tions of the maternal tissue of the placenta and of the walls of the capillary vessels being thus compressed and destroyed, the lacune are therefore formed.” Actual observations do not correspond to this sup- posed formation, but show in the placenta of early abortions the gradual development of the lacune by ectasiz from the beginning in the net-work of the capillaries amidst the mass of the placental cells, and while the villi of the chorion are still quite simple, as Robin has described with great accuracy. The for- mation of the lacune, therefore, precedes the forma- tion of the tufts of the villi, and cannot be an effect, 1 Op. cit., p. 341. 17 258 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. since observed before the existence of the cause as- signed by Kolliker. But I have been able to make an observation much more conclusive on the forma- tion of the lacunz independent of the presence of the foetal villi, having had occasion to study and describe the structure of the so-called uterine decidua in cases of extra-uterine pregnancy, and there found the ex- act and isolated anatomical structure of the mater- nal portion of the placenta in which existed lacune through ectasia of the vessels, without, of course, any trace of foetal villi. But it is not merely the inconsistency of the differ- ent opinions which have been broached for explaining the entrance of the foetal villi mto the lacune of the human placenta that helps us to the belief, based upon positive observations of comparative anatomy, that the relations between the two parts of the pla- centa are identical and constant in all the mammalia where the placenta is single, and, as I have said, of obscure glandular character. Other facts clearly ob- served in the human placenta, and demonstrated by men whose ideas are diametrically opposite to those which I have undertaken to prove, confirm the truth of my assertion, that the ectasia of the maternal ves- sels and the introflexion of their walls upon the villi constitute the only perceptible difference between the human placenta and that of the mammifera where it is single, and even in these the traces of ectasia are not, In some instances, wanting. Among the facts indicated, I shall mention those observations having reference to the transformation of the uterine vessels when they become placental, and those directed to the so-called double epithelium UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 259 of the villi. It has long been known that in the gravid uterus of woman are seen numerous small ar- teries with a spiral twist, of which arteries every trace is lost at the utero-placental limit and in the interior of the placenta. Farre formerly imagined that these said arteries might open directly into the placental lacune. Kol- liker has now taught that the short utero-placental arteries when they penetrate into the placenta lose their distinctive anatomical characteristics, that is, they no longer have muscular fibres or elastic ele- ments, and their whole wall is formed by an endo- thelial layer, covered with a thin sheath of connective tissue, which disappears and blends with the decidua serotina. Likewise the veins are no longer to be dis- tinguished from the arteries, and all traces of both are lost in the interior of the placenta, where alone the large lacune are found.’ Recently De Sinéty? has drawn attention to an im- portant demonstration, which completes those made by Kolliker. He noticed that the cells of the decidua . In woman form a circular sheath about the placental vessels, thus bringing a direct observation upon the human species into agreement with facts demonstrated with greater ease and certainty in some of the mam- malia, and which I have described in the rabbit and the dog. Unhappily, De Sinèty shows that he had not at all understood the ideas and the facts relating to the placenta, set forth by me in my previous works, and very inappropriately quoted by him. However, 1 Op. cit., p. 339. 2 Archives de Physiologie normale et pathologique, VIII. An., p. 345. Paris, 1876. 260 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. if the facts observed by him in the completely devel- oped human placenta harmonize with those already noticed early in its development, when there is seen a minute net-work of capillaries that become ectasic in the midst of the cells of the decidua or placental serotina, we shall be convinced that it is not that the walls of the utero-placental vessels are lost in these cells, as was indicated by Kolliker, but that so enor- mous a dilatation has taken place as to render it hard to perceive the endothelium, and to separate it from the placental cells that are elaborated by their ex- ternal walls. Positive demonstration of this will be obtained by bringing together certain accurate obser- vations which prove the endothelial wall of the ves- sels and their external cellular layer to be resting upon the foetal villi. Many anatomists and histologists used to affirm that in some portions of the villi they had observed two layers in the epithelium that covers the villi, and Kolliker has recently published! that, more especially when the epithelium is of suitable thickness, he has succeeded in distinguishing in it a deep layer with nu- cleated cells and a very thin surface, which, by means of acetic acid, may be detached under the form of a uniform membrane, in which the cellular limits are not very easily ascertained. The signification of these two layers, which, from the statements I have made, acquire no small importance, has not been brought out by any one, not even by Kéolliker, who, with much ability, has described the change in the histo- logical elements of the vessels, in their transition from uterine to placental. Even the observation repeated 1 Op. cit., p. 334. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 261 by him on the double epithelium led him only to re- mark that this second layer of epithelium of the villi had been frequently mentioned, and a little afterwards (holding only to the fact that in the extremity of the villi the epithelium appears single) he makes use of it to draw an argument in support of his opinion upon the mode of nutrition of the human foetus during ges- tation. ‘ In the extremities of the villi, at least,’ he writes,’ “ the foetal vessels are, so to speak, immediately beneath the epithelium, and as the capillaries of the villi have in this place only the endothelial typical wall, and the epithelial layer which there covers them is itself very thin, and since they swim in the mater- nal blood, the passage of the maternal fluid into the interior of the foetal capillaries must result without any difficulty.” From this it would appear that with- in the human placenta the osmotic process for the nutrition of the foetus would be easily carried on in the distal extremities of the trunks of the villi, but with difficulty in the villi, which are covered with the two layers of epithelium, and with still greater diffi- culty in the trunks, where abundant elements of the chorion surround the vascular loops and the minute net-work formed by them in the interior of the villi. Nor have the so-called epithelial buds of the villi, ob- served by so many anatomists in their different forms in the human placenta, hitherto had any signification whatever, but remained a simple recognition of fact. I have elsewhere pointed out and brought together observations to prove that the so-called buds of the villi were only partial hyperplasiz of the cells of the serotina which covered them, and within which pro- 1 Op. cit., p. 335. 262 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. truded an internal vascular loop of the villus, and it was owing to this that the branches of the primitive trunk remained always clothed in a cellular envelope throughout their manifold divisions. Modern opinions do not change the ancient idea, but determine the fact with greater precision, especially since the recent investigations which I have instituted upon the inti- mate structure of the villi in the human placenta. In Plate IV., Fig. 4, are represented the results ob- tained by these investigations. The means employed by me consisted in the immersion for some time, in an extremely diluted solution of nitrate of silver, of por- tions of villi from a fresh placenta, then treating them with acetic acid before putting them in glycerine, or treating them with nitrate of silver and submitting them to the ordinary methods of coloring with car- mine. With this and many other methods of treat- ment used by observers the double wall in the vill has been clearly demonstrated. In our illustration, and when the vessels of the villi are full of blood, they (a) are readily seen to be surrounded with the chorial tissue, in the midst of which appear large oval and granular nuclei (6). The chorial tissue and the foetal vessels form the internal mass of the villus, which is everywhere surrounded with a cellular layer (c, c') as this is, in its turn, with an external membrane that appears like a homogeneous and transparent layer (d'). This is best seen at the terminal extremities of the branches of the villi (d), exactly where Kolliker asserts that the so-called external epithelial layer is not visible, and that the deep-seated layer is simple and very subtile. Only seldom and with some dif- ficulty is any nucleus seen in this enveloping mem- brane. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 263 These observations of mine agree, then, at least in the fundamental part, with those made by Kolliker, and by many who have stated that the foetal villi of the human placenta are covered with two layers of epithelium. But how can that be called epithelium which is a uniform and compact membranous layer, in which, as Kolliker himself taught, the cellular ele- ments are only with great difficulty discovered ? With regard to the nucleated cells of the deep- seated layer, as it is called, all are agreed. Now, if we mentally picture the removal, from the tissue of the chorion and from the foetal vessels of a villus, of this double envelope by turning it back, do we not have a maternal placental vessel formed of a single wall everywhere surrounded by decidual cells, as we have observed in the placenta of many mammals having the placenta single? Have we not, in short, also in woman the elementary typical form of the maternal villus ? But, confining ourselves to the scrupulous exami- nation of fact, in the figure in question, at g is indi- cated the process by means of which occurs the rami- fication of a trunk of a villus. The protrusion of a vascular loop, which shall form a new branch of a villus, against the inner wall of the ectasic vessel oc- casions a new introflexion within its cavity (a sup- posed lacuna), not only of the mternal cellular wall, but also of its external wall, in which the structure of the endothelial cells is either much modified, or we have not been able clearly to demonstrate it. The mammillary shape of the epithelial buds of the villi, as is perceived at the apex of the branch of the villus in development (g), and the pedunculate form 264. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. of the buds indicated at h, which are so frequently met with in the villi of the human placenta, very probably show, the first, an initial and progressive process in the formation of a branch of a villus, and the second, an arrest of development in that process. The accurate knowledge now presented upon the formative process of the placenta, upon the intimate structure of the new-formed placental vessels, upon the origin of the decidual and placental cells, as well as upon the ectasia of the maternal vessels in the placenta of the quadrumana and of woman, appears to me to be all in harmony, one part with another. The different observations that have been gradually accumulating, upon which a final decisive opinion was still wanting, receive a clear and simple interpreta- tion, and I do not believe myself mistaken in affirm- ing that the ideas acquired substitute simplicity and clearness for the many uncertainties and important errors which have hitherto been held as to the ana- tomical structure of the human placenta. By these researches we have moreover been able to demon- strate that the relations between the foetal and the maternal portion of the placenta in woman are per- fectly identical with those observed in single placenta in the other mammifera. We have traced amid the manifold and remarkable varieties of form the unity of the anatomical type of the placenta in the different classes of mammiferous animals, and discovered, as re- sulting from it, the physiological unity of the law that governs the nutrition of the foetus in all vertebrates, whether its life is completed within the body of the mother or in an egg outside of it. In summing up, then, the subjects discussed, the UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 265 principal facts may, I think, be comprehended in the following conclusions : — (1.) Immediately after conception, the first fact which is established in the uterus is a destructive process that affects its inner surface. In some ani- mals and in woman this process is limited to the mere epithelium, whilst in other animals, as in the rodents, the destructive process attacks the whole sub-mucous connective layer, including the vessels, nerves, and utricular glands found therein, as far as the inner surface of the uterine muscular tissue. These two facts, which seem in regard to their im- portance so widely divergent, have nevertheless, in the rodents as well as in woman, one common, ultimate, and identical result, namely: that of the denudation of the internal surface of the uterus. (2.) The extent and depth reached by the destruc- tive process in the full segments of the gravid uterus in rodents serve to show, very plainly and positively, that the formation of the decidua and placenta is due, neither to a tumefaction nor to a transformation of the anatomical elements preéxistent at the time of conception in the uterine mucous membrane; and that, if the utricular glands also are affected and destroyed before the placenta is developed, they are necessarily to be regarded as completely extraneous to the formation of the placenta. Though in other animals, when these remain increased in volume through the whole time of gestation, I cannot deny to them some share in the nutrition of the foetus, still the facts observed in the rodents prove that they are not essential to the nutrition of the foetus in all the mammalia. 266 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. (3.) The destructive process more or less deep on the internal surface of the uterus is in all cases indispen- sable, because this is what facilitates the setting up of the neo-formative changes from which will result the maternal portion of the placenta. The deep-seated destructive process which is observed in the rodents serves admirably to demonstrate the neo-formation of the decidua and placenta, which in the rat has been followed in its minutest particulars from the moment of the arrest of the ovum in the uterus. (4.) The neo-formative process of the uterine or maternal portion of the placenta consists in the pro- duction of new vessels, which are distinguished from the ordinary uterine vessels by two special character- istics: first, the arterial as well as the venous vessels have only a simple endothelial wall; second, from the external surface of this wall is elaborated a layer, more or less thick, of special cells not separable from the wall of the vessel. These are the so-called de- cidual and placental cells. That the foetal portion of the placenta is itself due to a neo-formative process has not been, and cannot be questioned. (5.) It is from the constant relation established between these two parts of new formation that the placenta is developed. The manner in which this relation is established gives rise to the different forms of placenta known in the mammalia. (6.) The elementary or primordial form of the two fundamental parts, from which results the placental formation, may- be anatomically determined by the form and structure of a simple villus, by the foetal as well as by the maternal portion; the function alone differs in the two villi, bemg absorbent in the foetal, and secretory in the maternal villus. UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 267 This elementary and typical form of the two parts constituting the placenta in the mammifera is not im- aginary, but is demonstrated in its simplicity by ob- servation. It is easily enough recognized in the foe- tal portion, in the villi of the chorion, especially in the simpler forms of diffused placenta, as, for instance, in the sow and in the cetacea, and at the beginning of development in the human species. In the mater- nal portion the simple, elementary form is found to be developed and maintained through the whole pe- riod of gestation in the uterus of certain viviparous fishes. (7.) The manner in which the relation between the two parts is established may be by simple prox- imity, contact, or by intimate cohesion. When the relation is that of simple nearness, the maternal por- tion of the placenta manifestly presents the form of a glandular organ and has its limitation by the repeti- tion of secretory villi upon the inner surface of the uterus, which, uniting with each other in various ways, give rise to the formation of crypts or glandu- lar follicles, simple or compound, into which enter the absorbent villi of the chorion. When the rela- tion is more intimate and an adherence takes place between the two parts before mentioned, as in cases of single placenta, whether of zonarial or discoidal form, the glandular character is concealed by the very fact of the adhesion, but the fundamental condition remains constant, the contact, in this case direct, be- tween the vessel of the absorbent villus and the epi- thelium of the secretory villus, which is never lost in any instance. (8.) Only two very simple changes occur in the 268 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. fundamental parts of the placenta when single, and they are the factors of the manifold differences which are met with: first, the loss of the epithelium of the absorbent villus, which is not important, since there is established direct contact of the vessel of the villus with the secretory epithelium of the maternal villus, and this fact is constant; second, the dilatation or ectasia of the vessel in the maternal villus, and this fact is remarkable only in the placenta of the quad- rumana and of woman. The ectasia in the maternal vessels, already shown under a rudimental form in the placenta of certain mammals, has been indicated by Eschricht and by Turner as representing the large lacune which are observed in the placenta of some of the quadrumana and of the human species. But these supposed lacune have been the chief, if not the only stumbling-block to the exact Knowledge of the structure of the human placenta, although anatomists were aware that ectasia took place in the placental vessels in their first phases of development. The belief that the lacune were really large cavities, as they had the microscopic appearance of being, and not the maternal vessels greatly dilated, was held by all as a truth proved and indisputable, and it was through this belief that two other deceptive appear- ances were received as actual truths, namely: that the villi floated in the maternal blood, and that the epithelium covering them appertained to the foetus instead of the mother. I have demonstrated as facts certain things ascer- tained with regard to the earliest period in the devel- opment of the human placenta, namely, first, that the maternal vessels which course in the compact UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 269 mass of the decidual cells and the placenta are af- fected by an ectasic process; second, that the foetal villi, when simple, are in contact with the aforesaid cells; third, that the simple foetal villi at first pro- liferate and then become arborescent. I have shown that, harmonizing these facts in their progressive de- velopment, there must of necessity occur a protrusion of the villi within the cavity of the dilating vessels, and that this protrusion cannot take place without an introflexion of the walls of the vessels that are pressed upon by the proliferating chorial villi; there- fore the first relation that is established in the human placenta between the chorial villi and the cells of the decidua is still maintained unchanged, even when the placenta has completed its development. Asa con- sequence of the intimate relation existing between the foetal and maternal portions, the villi lose only their primitive epithelium, and finally there is also established in the human species, between the two parts of the placenta, a relation identical with that which we have observed in single placenta in other mammals in which is wanting only the ectasia of the maternal vessels. Setting aside the fundamental errors, many facts already observed by able anatomists in the human placenta, which have remained doubtful or were wrongly interpreted, now receive a clear and precise explanation. (9.) The belief that the villi in the placenta of woman were floating in the blood of the lacuna gen- erated the physiological error that the nutrition of the foetus, not only in the human species but in all mammals, took place through an osmotic exchange 270 UNITY OF TYPE IN PLACENTAL DEVELOPMENT. of the two bloods, although in the case of diffused or multi-cotyledonal placentse, the facts openly contra- dicted such an assertion. Besides, in all cases, where the placenta is single, the vessel of the absorbent vil- lus (of the foetal portion) never comes in contact either with the blood or with the wall of the mater- nal vessel, but there is always interposed between the walls of the two vessels, and consequently of the two bloods, a cellular layer which is the epithelium of the maternal villus; and that this is secretory is confirmed by the obvious glandular appearance which is observed in many animals in the maternal portion of the placenta when it has the diffused or multi-cotyledonal form. (10.) The nutritive material which is to serve for the growth of the foetus in all the vertebrates is fur- nished by the mother. In mammals it is supplied by the maternal portion of the placenta, gradually, as the foetuses are developed. In the oviparous vertebrates the material, in the quantity necessary to the de- velopment, is emitted in a mass from the mother, in the form of yolk with the egg. In the mammiferous, as in the oviparous, animals the absorbent or foetal part of the placenta does not change, and it is by means of an absorbent villus, more or less complicated, that the material elaborated by the mother is con- veyed to the foetus. It is, therefore, but one law, a physiological modality, that governs the nutrition of the foetus in all the vertebrates. (11.) The observations made upon the primordial or rudimentary forms of the placenta in certain vivipa- rous fishes leave it doubtful if the marsupialia should be considered as mammals without placenta. From UNITY OF TYPE IN PLACENTAL DEVELOPMENT. 271 the very little known about it, even in these animals, there exists, for the nutrition of the foetus in the body of the mother, the relation of contact of a secretory surface, the uterine, with an absorbent surface, foetal chorion without villi. This relation is observed, in Mustelus levis, between the large umbilical vesicle without villi and the large folds of the uterine mu- cous membrane, which embrace and surround the foetuses and their envelopes. The exact actual obser- vations which have been also lately collected by Tur- ner in no wise, then, allow us to accept the recent opinions of Kélliker, who considers all the mammals of diffused placenta as implacentate. SUMMARY AND CLASSIFICATION. In the ten years that have elapsed since the publi- cation of my first inquiries into the intimate structure of the placenta in the mammals and the human species, I have not let pass a single favorable opportunity of procuring new material for study, either to confirm the observations already made, or to extend and en- large as much as possible the opinions I had published, and to correct them if erroneous. But the great difficulty met with in obtaining gravid females of animals at different periods of gestation renders the observations less complete than I could wish, and the poverty of those who in Italy cultivate the natural sciences prevented me from making any © investigation or acquisition abroad, as I very much desired, and my work would have remained isolated, certainly it would have borne little fruit, but fortu- nately during this period the distinguished anatomist, 1 Professor Ercolani writes me, in reply to inquiries as to the conclu- sions at which he has arrived, since the publication of his memoir, that while gratified that the ‘results of his long-continued studies are about to be presented to the knowledge of his colleagues in the great Amer- ican republic,’’ he confesses a hesitancy in offering further deductions because of the fear that his ‘‘long-continued labors might have led to conclusions so important, that in announcing them it would be a duty to furnish a long series of actual observations, with the inferences and de- ductions drawn from them.’’ Since opportunity is not afforded for doing this, he has kindly sent me what he considers ‘a brief and imperfect summary of the labor thus far accomplished.’? I take great pleasure in adding this to the present work, and believe it will be accepted by scien- tists as of great value. — H. O. M. SUMMARY AND CLASSIFICATION. 273 Professor William Turner, of Edinburgh, devoted him- self, with a rare steadiness of purpose, to this kind of investigation, and had the happy opportunity of be- stowing his learned and conscientious researches upon no small number of animals either rare in themselves or difficult to obtain in a state of pregnancy. He availed himself of the rich material for study which cultivated England can afford to her sons who honor- ably pursue the different branches of human knowl- edge. The studies and the numerous observations of Turner, and those more limited and fewer of Harting and Creighton, gave me the greatest satisfaction, be- cause they either confirmed those I had made, or, by extending them to other animals which I had not examined, largely established my fundamental dem- onstrations. At first there appeared a slight disagreement be- tween the observations of Professor Turner and my own. I had very concisely asserted, contrary to the doctrine taught by Sharpey and received by other able anatomists, that the utricular glands of the uterus not only did not receive in their interior the villi of the chorion, to form with them the placenta, but that they did not at all enter in any case into the formation of that organ, and had no important office in the nutri- tion of the foetus, since it, by means of its envelope, was placed in direct relation with the uterus of the mother. Turner, beginning his researches on the pla- cental formation of the Orca gladiator, showed him- self doubtful about accepting this general conclusion, so remote from the ideas then held by the most fa- mous anatomists, but afterward extending his investi- gations to other animals having a diffused placenta, as 18 274 SUMMARY AND CLASSIFICATION. has the orca, and to those where it is pluri-cotyledonal in form, as in the domestic herbivora, with noble sin- cerity he repeatedly declared that the utricular glands in no case took part in the formation of the placenta, and that the uterine crypts which receive the villi, even in the Orca gladiator, are to be regarded as alto- gether of new formation. Apart from this slight disagreement, which, as re- gards the manner of nutrition of the foetus in the uterus, was of secondary importance, the fact still re- mained, which had seemed to me of greater weight, and which I had sought to bring out clearly, namely, that in animals as well as in woman the nutrition of the foetus is in no case effected by means of an osmotic exchange between the two bloods, but always takes place by the neo-formation of a special secreting or- gan, furnished by the uterus of the mother. Turner, for the designation of glandular organ given by me to the secretory organ, substituted the more general and comprehensive name of secretory surface, which is either placed in simple contact, or else intimately united, with an absorbent surface appertaining to the foetus. The exactness and precision of the observations of Turner and others thus strengthened my own con- clusions, and with a generosity rather unique than rare, valuable material for study was placed at my disposal by the distinguished professors Theodore Bi- schoff and Milne Edwards, to whom I am happy to ex- press the sincerest gratitude. By means of the care- ful investigations I was thus enabled to institute, there was afforded me a good opportunity to enlarge the sphere of my views, and to extend the narrow circle SUMMARY AND CLASSIFICATION. 279 of the analysis and comparison of separate facts, to which for a long time I had been obliged to confine myself. The new facts observed, though adding some beau- tiful and interesting characteristics useful to be known, all relate especially to the manner of the structure of the placenta in different animals, and, so far from changing, they rather confirm all the deductions and the fundamental opinions which I had stated in my earlier works. To describe the anatomical peculiarities seen in the intimate structure of the placenta in those animals re- cently examined is not, I think, what you require of me, nor would this be the fit place for making a mi- nute and necessarily long exposition of them. I flat- ter myself, therefore, that it will be more satisfactory to sum up briefly all the anatomical facts relative to the most remarkable differences observed in the pla- cente of the different mammifera, and then to touch on the general conclusions which, in my opinion, are to be drawn, applying what has been learned to the taxonomy and the phylogeny of the mammals, sub- jects on which learned scientists spend, and have spent, many years of labor. While carrying on investigations upon the forma- tive process of the placenta in woman and in the fe- males of the mammiferous animals, I was led to trace out the unity of the anatomical type from the histo- logical point of view in all the different forms of pla- centa which up to that time had been observed. I endeavored to show that this unity consisted in the neo-formation of a simple villus, in the strict anatom- ical sense of the word, on the part of the mother as 276 SUMMARY AND CLASSIFICATION. well as on the part of the foetus (villus secretory or maternal; villus absorbent or foetal). I now add that to this single type are subordinated also the new forms of placenta which have been seen and described by others and by myself. I was at that time content with having shown that to the unity of the physiological process or office of the placental organ corresponds the histological unity of the anatomical type governing all the various forms under which the placenta is observed; that they owe their origin solely to a different relation which is es- tablished between the maternal and the foetal villi; a simple relation of proximity and contact in the dif- fused and many-cotyledoned, in which, whatever may be its form, the epithelium of the absorbent or foetal villus comes in contact with the epithelium of the secretory or maternal villus; a relation of intimate union, on the other hand, between these two species of villi in the zonarial or single discoidal placenta. I also stated that there were but two very simple fac- tors in these apparently very important anatomical differences; that they consisted in the loss of the epi- thelium in the absorbent villus when the simple rela- tion of contact is changed for that of intimate union, and in the ectasia or non-ectasia of the vessels of the maternal villi when we inquire into the differences be- tween the single discoidal placenta of animals and that of the human species. Later observations have shown me that not all the zonarial placenta have an identical intimate structure, as is generally believed, but that even in animals where it is single and of discoidal form there are ex- amples of the duplex and differing relation between SUMMARY AND CLASSIFICATION. 277 the foetal and the maternal villi, or between the ma- ternal and foetal portions of the placenta. This diver- sity has served zodlogists as a basis for the division of mammals into deciduate and non-deciduate. I think that these recent investigations may have some importance in disturbing the fundamental basis accepted by zodlogists for distinguishing the mam- malia, and that they may also, with some simplicity and clearness, lead to the recognition of the fact that not only the histological anatomical type, but also the microscopic anatomical type, preserves a true unity of form. Proof of this is obtained by examination of the initial or rudimentary forms in which the pla- cental organ manifests itself in certain cartilaginous fishes. Miller was the first to distinguish, among cartilag- inous fishes, the Plagiostomi into acotyledonous and cotyledonous, placing with the former those where the ova, after having been fecundated, remain up to their complete development in simple contact with the internal wall of the incubating chamber; and with the latter, those in which the ova, with a part of their large umbilical vesicle, become intimately united with the inner wall of the chamber or uterus, by means of mutual introflexion between the folds of the two surfaces. Later, Bruche described a villous neo-formation on the mucous membrane of the gravid uterus of certain species of fishes, the Selachu, which forms a sort of nest from which the ovum of those fishes derives the material necessary to the complete development of the foetus. All the principles that underlie exact knowledge of the intimate structure and real value of the manifold 278 SUMMARY AND CLASSIFICATION. microscopic appearances which the placenta assumes in all mammals are included, as I believe, in these few and simple facts observed in certain fishes. For if in the past anatomists and zodlogists were confused and embarrassed by the varied and manifold forms of the placenta in the different mammiferous animals, to-day we are, I think, on the other hand, forced to admire the simplicity with which nature maintains and exhibits unity exactly where there appeared to exist the greatest and most remarkable diversity. Uniting all the observations made by others or my- self upon the exterior forms and intimate structure of the placenta, which permit being judged of with certainty (many older observations not admitting of such accuracy),I shall now attempt to show that in a comparison of form and structure in the placental organ in the mammalia, the same very simple facts are repeated, though more fully and perfectly, which I have already pointed out as seen in certain carti- laginous fishes. It will be noticed that I have indi- cated rather more forms of placenta than are gener- ally recognized by anatomists, and, unfortunately, I am obliged in this communication to present as mere assertion that which needs to be demonstrated with a minute anatomical description of facts, to which I can here only allude. I trust, however, that for those who have pursued carefully scientific investigations of this character even these hasty suggestions on the different placental forms and structure may suffice to convey my idea in explanation and completion of the teachings left us by the illustrious von Baer. The facts adduced by this learned embryologist to distinguish two funda- SUMMARY AND CLASSIFICATION. 279 mental forms of placental development in mammals, from conception to the act of delivery, with or with- out traumatic lesion of the internal surface of the uterus, remain unchanged, because they are indispu- tably true, and correspond exactly to those observed by Miller and others in the acotyledonous Plagios- tomi without lesion of the chamber of incubation, and in the cotyledonous with lesion of the chamber by separation of the folds which were closely united dur- ing gestation. The distinction taught by von Baer occurs in certain cartilaginous fishes, and has its coun- terpart in that advanced by Huxley for the mam- malia, the acotyledonous Plagiostomi corresponding to the non-deciduate, and the cotyledonous to the deciduate mammals. Harmonizing these facts with what is known of the placental organ, the doctrine of von Baer may be thus expressed : — (1.) Mammalia in which the nutrition of the ovum takes place through simple contact of its absorbent surface with the internal or secretory surface of the uterus. (Acotyledonous Plagiostomi.) (2.) Mammalia in which the nutrition of the ovum takes place through the intimate contact and union of a part of the absorbent surface of the ovum with a part of the internal or secretory surface of the uterus. (Cotyledonous Plagiostomi.) Let us now see what are the successive changes, or modifications, which, still maintaining the funda- mental typical form seen in the fishes, are met with in the placente of those of the mammalia that have hitherto been observed and studied. 280 SUMMARY AND CLASSIFICATION. ACOTYLEDONOUS PLACENTZ. Under this denomination I include all those of pla- cental formation observed in mammals in which, not- withstanding the numerous and varied microscopic ‘ forms they present, there is maintained in all cases propinquity or simple contact between the absorbent or foetal and the secretory or maternal surfaces. As to the exterior forms the following species may be distinguished. ACOTYLEDONOUS PLACENTA, SIMPLE. This form, which, so far as is known, is that most nearly resembling that of the acotyledonous Plagios- tomi, may have been observed in the Ornithodelphia in Ornithorhyncus paradoxus, and among the Didel- — phia in Macropus major, but it must not be concealed that positive observations are still wanting to prove that in this last, at least, there may not take place on the internal surface of the uterus a villous neo-forma- tion analogous to, or representing, that foun in some fishes among the Selachii. ACOTYLEDONOUS PLACENTA, VILLOUS AND DIFFUSED. In this form of placenta the relation of simple con- tact between the two surfaces of absorption and se- cretion is greatly increased by numerous foldings of both surfaces, and by the neo-formation of many villi upon them. In this group are included the following: The simple diffused villous form in which the facts already indicated are confirmed; the very numerous villi of the two surfaces come in contact and are dis- posed in linear series or in groups on the folds of the SUMMARY AND CLASSIFICATION. 281 chorion and the uterine mucous membrane. This form of placenta has been observed in Sus scrofa, Propithecus Verrauxvi, Lemur rufipes, and in some species of the genera Lepilemur, Hapalemur, and Cheirogaleus. The compound diffused villous form differs from the preceding only in the fact that the secretory or maternal villi, over the whole internal surface of the uterus, are united to each other in such a way as to constitute so many small depressions, having the shape and the office of glandular organs, which re- ceive in their internal cavities the foetal absorbent villi. According to the greater or less degree of perfection of the neo-formed glandular organ in this general type of placenta, we may make a distinction between those in which the glandular organ is of cryptal form and those where it is follicular. The cryptal form has been described in Pangolinus, Del- phinus phocena, Balenoptera Sibbaldii, Orca glad- iator, Halicore dugong, Tragulus Stanleyanus and meminna, and in Hyomoschus aquaticus. The rhi- noceros and tapir families present this form. The follicular has been described in Equus caballus and asinus, in Camelus dromedarius, and in Monodon monoceros. ACOTYLEDONOUS PLACENTA, COMPLICATED VILLOUS. There is but a single example as yet known of this form of placenta, which has been observed only in Elephas indicus. It differs from those already men- tioned in this: at the poles of the ovum it presents a simple and localized diffused villous form instead of at its middle part, where is developed a species of 282 SUMMARY AND CLASSIFICATION. distinct zone, composed of villi closely crowded to- gether and received into numerous new-formed gland- ular crypts. ACOTYLEDONOUS PLACENTA, LOCALIZED VILLOUS. The simple contact between the absorbent and the secretory surfaces 1s maintained, as in the foregoing forms of placenta, save that the relation of contact is more or less complicated and is established exclu- sively at certain points, which may be very numer- ous, few in number, or even at one place only, more or less extended or limited. The glandular neo-for- mation thus localized upon the maternal surface is perfected and elevated in its structure, acquiring the forms of a compound follicular gland. By reason of this complication the chorial villi are given off from the foetal surface in tufts, or groups of tufts, of villi more or less branching or arborescent. I do not accept the name of pluri-cotyledonous, employed for these forms of placenta, because, as I shall point out, I have seen this structural type in placente of zonarial and even of single and discoidal forms. In this group, then, we may distinguish the following : — With diffused and extended localization over many points of the two surfaces. Examples of this are afforded by the well-known placental formation in Bos taurus, Ovis aries, and Capra hircus. Here, also, is to be referred the man- ner of forming the placenta in Camelopardalis gi- raja and probably also that of Hippopotamus am- phibius, in which, however, the centres of localization would be smaller and more numerous. SUMMARY AND CLASSIFICATION. 283 With localization limited to a few points only of the two surfaces. In this form are classified the placenta observed in Rangifer tarandus and in Cervus dama, capreolus, elaphus, axis, and porcinus. A remarkable peculiar- ity or exception relative to placental formation in the deer has lately been described in Cervus mexi- canus, in the gravid uterus of which were observed three large cotyledons, several dozen smaller ones, and also numerous small, simply villous spots. In this is thus afforded a fine example of passage from the forms of simple villous placenta to the far higher one now under consideration. With localization limited solely to the middle zone of the ovum. To this form are to be referred the zonarial placen- tee described in Phoca vitulina, Phoca bicolor (Mona- cus albiventer), Halicherus grypus, Hyrax capensis, and among the Hdentata in the genus Orycteropus. The same is met with also in Lutra vulgaris and in Mustela foina, martes, and vulgaris. I ought here to remark that the zonarial form which the placenta has in these animals has led anatomists to believe that therefore the intimate structure must also be identi- cal with that .of the zonarial placenta of the carnivora, which, as I am about to show, is entirely different. With localization clearly distinct at one point of the surface of the ovum. The placenta is single and of discoidal form. The intimate structure is that common to all acotyledo- 284 SUMMARY AND CLASSIFICATION. nous placenta. It has not hitherto been observed except in Talpa europea. COTYLEDONOUS PLACENTZ. I include under this generic name all those forms of placental structure which have been found in mammals where the fundamental character that dis- tinguishes them from those previously indicated is never wanting, namely, the intimate union, at a space of greater or less extent, between the secretory and absorbent surfaces, a union to which I have already called attention as taking place by means of certain folds in the incubating chamber in the Plagiostomi, for this reason called by Miller cotyledonous. The secretory surface in these placenta is formed by the maternal vessels which convey in the mater- nal blood the materials necessary to the secretion, and by the organic secretory elements, which consist of the peri-vascular or deciduate cells that, in all cases, surround the maternal placental vessels. The foetal or absorbent surface is also formed by the ves- sels which convey to the embryo the separate ele- ments capable of assimilation. The chorial villi, con- stituting the absorbent surface, coming in contact and close union with the deciduate cells of the secret- ing surface, lose very properly their external epithe- lium, rendered by this union useless and troublesome to the villi for the discharge of the duty they are to perform ; therefore these forms of placenta may be styled vascular, since the chief differences noticed among them depend upon the manner in which the union is effected between the two vascular surfaces. The species of these placentz are : — SUMMARY AND CLASSIFICATION. 289 Cotyledonous Placente of incomplete vascularization. Even the older anatomists distinguished two parts in these forms of placenta, one which belongs to the uterine surface, and which the vessels of the foetal villi do not reach (the maternal portion of the pla- centa); the other which is carried over it and to- wards the uterine cavity and the foetus. With this part alone come in contact the vessels of the villi of the absorbent surface, which, deprived of external epithelium, unite with the secretory cellular elements that surround the vessels of the maternal villi (the foetal portion of the placenta). This form of pla- centa has been observed in Cavia cobaya, Dasy- procta aguti, Mus musculus and decumanus, and in Lepus cuniculus and timidus. Cotyledonous Placente with complete vascularization. The foetal vessels of the absorbent surface divested of epithelium come in direct contact with the secre- tory cellular elements which surround the vessels of the whole maternal portion. Ordinarily in this kind of placental formation the diameter of the maternal vessels does not show partial ectasic dilatations, and only in a few cases are there rudimentary indications of them anywhere. But dilatations in the form of lacune are always wanting, and there is no distinc- tion of the placenta into two parts as in the preced- ing species. The shape of these placenta is zonarial in some animals, in others discoidal. It is zonarial in Canis vulpes and domesticus, and in Felis catus do- mesticus. It is discoidal, and has been studied, in Erinaceus europeus, in Vespertilio murinus and noc- 286 SUMMARY AND CLASSIFICATION. tula, in Pteropus medius, Noctilio leporinus, and Phyllostoma hastatum. Very probably this same form has been observed in Centetes ecaudatus. Cotyledonous Placente with complete vascularization and with ectasia in the vessels of the secretory sur- face, or maternal portion of the placenta. In this form of placenta the external surface of the dilated vessels of the maternal part conveys the peri- vascular and secretory cells against the walls of the vessels of the absorbent foetal surface, which, accord- ing to the degree of dilatation that takes place in the vessels, remains only in simple contact with these, or is co-involved with the secretory cells and with the walls of the maternal vessels. The external form of the placenta and the degree of dilatation of the utero- placenta] vessels may serve to determine some species of placenta in this group, also, e. g. : — External form bell-shaped and composed of many lobes united together, with regular and uniform dila- tation in the vessels of the secretory surface. This variety of placenta is found in Bradypus tri- dactylus and didactylus, or Cholepus Hoffmanni ; in this appear, also, certain larger dilatations at some points in the said vessels, representing the beginning of the formation of lacun®. External form unilobed, discoidal, or circular, with irregular ectasic dilatation of the vessels of the secre- tory surface, so as to produce lacune. Observed in Tamandua tetradactyla, and Dasypus gymnurus, novemcinctus, and sexcinctus. To this form SUMMARY AND CLASSIFICATION. 287 is probably to be referred that seen in Cyclothurus didactyla. External form bilobed, that is, composed of two masses of discoidal shape, more or less separate from each other. Lacunose ectasia in the maternal vessels. Observed in different species of Simie, as in Hapale jacchus, Mycetes ursinus and seniculus, in Cercopithe- cus sabeus, Cynocephalus sphinx, Semnopithecus nasica and mitratus, and in Macacus nemestrinus and cyno- molgus, etc. External form unilobed discoidal. Lacunose ectasia as n the foregoing. Observed in the Anthropoid apes, in Troglodytes niger, and in the Human species. Iam aware that some at least of the anatomical facts which I have simply indicated need to be minutely de- scribed in order to acquire such value as’ they may have, but it is impossible to do this in so brief a sum- mary as is here given, and I therefore confine myself to the outline as furnished. Iintend to make a full dem- onstration, with anatomical analysis of the facts, in order to show that there are animals having the pla- centa of zonarial and discoidal form which are not de- ciduate in the anatomo-zodlogical sense of the word as now employed by modern writers; and that the ecta- sia ofthe utero-placental vessels, even when presenting the appearance of large lacune in the interior of the placenta, not only is not an anthropological character- istic, as was once thought, of the human species, but besides being common to the Stmie has been also ob- served in the placenta of some among the Edentata. 288 SUMMARY AND CLASSIFICATION. In considering the various forms noticed in the placenta of the different mammals, others had been successful in detecting a gradual and progressive de- velopment from the simplest up to the highest, those of the monkeys and the human species; and that this regular progress in-the development of the pla- cental organ bore no direct relation to the rank held by the different species of mammals in the scale of being. The careful researches and minute distinc- tions which I have above recorded help to confirm these very important conclusions. I call them very important, because they are to-day brought forward to show that inquiries concerning the form and structure of the placenta have not, and cannot have, any useful application to zodlogical taxonomy and the phylogeny of the mammalia. I have already pointed out in preceding works, that I thought the basis accepted by zodlogists for distinguishing the mammalia into deciduate and non- deciduate to be erroneous, the uterine decidua repre- senting in all these animals the initial neo-formative process which gives rise to transformations, more or less extensive, of the secretory surface, or, in other words, to modifications which the new-formed villi undergo upon that surface. In mammals styled non- deciduate, having diffused placenta, whatever may be its species, the whole decidue or primitive villi are changed into secretory organs of more or less simple glandular forms, and the same fact is repeated, but limited to certain points only of the secretory surface, in non-deciduates having pluri-cotyledonous placenta. In woman, the type of the deciduates, the decidua, indeed, is formed upon the whole internal surface of SUMMARY AND CLASSIFICATION. 289 the uterus, but there is only one part of the new- formed decidua, that, namely, against which the ovum is fixed, that becomes placental; all the remaining portion is arrested in its development and becomes that external part of the foetal envelope which is known as decidua vera, concerning the origin and structure of which there is so much discussion by anatomists and obstetricians. According to these views the true deciduates par excellence, those, namely, in which the whole of the primitive decidua is transformed into maternal pla- centa, would be those mammals which are thought non-deciduate. If we restrict the name of deciduates to those in which, as was pointed out by Weber and von Baer, there takes place in the act of parturition a traumatic lesion of the uterus, through the caducity of the maternal portion of the placenta, even then the received basis is fallacious, since, as I have indicated, not only among animals having zonarial placenta would some be deciduate and others non-deciduate, but there might be an example of one considered deciduate, with the placenta single and discoidal, in which in the act of delivery the two parts constitut- ing the placenta become enucleated as happens in the cotyledons of some Ruminants. That among the Edentata there were some that should be classed with the deciduates, and others with the non-deciduates, was already known to zodlogists, who considered these facts as exceptional and con- fined to that order of mammals. It appears to me, however, that the exception goes too far, and as such can no longer have any actual value. Anatomists and zodlogists have always foreseen the 19 290 SUMMARY AND CLASSIFICATION. importance that studies on the placenta must have in a natural classification of the mammalia. The numerous attempts made from Everard Home down to Huxley show this unquestionably. But after so many toilsome and minute researches, anatomists and zodlogists have been led to conclusions entirely op- posed to the end for which they had expended so much time and labor. As step by step they acquired more extended and complete knowledge of the form and intimate structure of the placenta, the conviction deepened that the doubts already raised by Owen as to the applicability of these studies to zodlogical taxonomy would not lead to useful results, and to- day, through the labors especially of Rolleston and Turner, it is plainly asserted that researches on the placenta neither have nor can have any useful appli- cation to zodlogy. Is this assumed discrepancy between embryolog- ical and zodlogical studies to be held as sufficiently proved, and henceforth to be considered indisputa- ble ? I will also, on this most important question, briefly state the conclusions at which I have arrived. Not- withstanding the serious disappointments sustained by all those who had hoped for a blaze of light from the application of studies upon the placenta to z06- logical taxonomy and phylogeny, I do not think that there were many who were willing to abandon a con- viction which, though reached a priori, was yet deeply and generally felt by learned men, as the history of science shows. The idea appears too simple and too logical to be relinquished, that the form of the foetal envelopes and the placenta, which have so great a SUMMARY AND CLASSIFICATION. 291 share in the nutrition of the foetus, must have, in the embryological point of view, a nexus or closely con- necting bond with the forms which the animals will exhibit when arrived at their complete development. Though we may be compelled to abandon even the hope that the paths hitherto followed for applying the knowledge obtained about the form and structure of the placenta to zodlogy and phylogeny may lead. to useful results, yet it has seemed to me that re- calling to notice and expanding, by the knowledge now possessed, an idea which was expressed by von Baer, but neither by him nor by others sufficiently considered, we may arrive at some important conclu- sions. It was known to von Baer that in the foetal envel- opes of certain mammals, the umbilical vesicle in- creased in volume during the period of gestation, and remained voluminous even in the act of parturition ; and upon this fact, with that of the rapid disappear- ance of the aforesaid vesicle in other animals, von Baer proposed to classify the mammals as follows: — Persistent. Increase of the Allantois. The umbilical vesicle persistent but very small. Rodentia. Persistent, moderate size. Insec- tivora. Persistent, very large. Carnivora. The umbilical vesicle increases lit- tle. nt umbilical cord very long. Simic. Homo. Increases lit- tle, and the Allantois | ye isolated masses or is persistent cotyledons. Lumi- nantia. Umbilical Vesicle. | and the INERTE Pachyder- mata and Cetacea. | Placenta is 292 SUMMARY AND CLASSIFICATION. I shall not dwell on the many incongruities which observation of facts would reveal in this arrange- ment. I will only remark that the simple occurrence of the presence and volume of the said vesicle and of the allantois would give rise to not a few contra- dictions, or at least to very serious difficulties in its rigorous application. Later anatomists remarked that in some animals it was the allantois alone that took part in the forma- tion of the placenta, while in others, it, as well as the umbilical vesicle, had an important share. This fact, which I followed with some degree of attention in the Cheiroptera and some of the rodents, seemed to me of great value, and deserving of more careful consideration than to be allowed to remain in the field of simple anatomical observation ; adding, then, my own investigations to those of others, I endeav- ored to ascertain what would result from separating the mammalia into Allantoidea and Omphaloidea, ac- cording as into the constitution and the vasculariza- tion of the placenta the allantois alone entered, or both the allantois and the umbilical vesicle. The fol- lowing are the results, briefly stated, which were thus obtained. I have noticed only those groups in which in some species of the different genera the forms of the placenta are known. The table might serve for a natural zodlogical arrangement as well as for the phylogenetic order of the mammalia, not progressive in a direct series, but progressive, and in lines diverg- ing from each other. 293 SUMMARY AND CLASSIFICATION. SRI episdoAqyyoy | vpisdomevg sv ermydog e IYdjopogniuIio | vrydlepid | eIqd[opouo]{ CR) | pe AL | | d | | BIOAT]OISUT equepoy vaieqdoi1syO 8908490) eyeynsug | | | eprd [ey SI toprourqd[o | epnozuag FASE voplouxeeq | | QpI9OBULIH eJemsunque | | | | (squeurtana) (squeurwma-t0U) | ey Ajoe polly ey Ajoeponsy e | AJoRpossiieg BIOATUIGO, | | | = eprjemed epg eprjor1ss0uryy erpedraurg | | | | VplNsely, epruejododdry epriidey, SVpTpejsnyl | | | 110Ydo[309 epmby eprueg Baprlosoqolg | | | | | - epllaq eaproovt AFT C}eZUIPH PIRO eplinuey | e peruis | epiodo1gzuy owoH 294 SUMMARY AND CLASSIFICATION. I will not now enter into even an outline of the arguments of various kinds with which I seek to sup- port the basis of the general idea running through this attempt at a zodlogical arrangement which may reconcile embryology with the taxonomy and phylog- eny of mammals. The inferences from it are many and important, but I shall confine myself to asking attention to a few only of the clearest actual results ‘shown by comparison of the diverse forms of placenta as observed in the different animals which are re- ferred to the groups indicated in the table. Espe- cially will it be noticed that the various forms of pla- centz ordinarily included under the generic name of diffused placentz are observed only in the Allantoi- dea, and that there is not a single example of these forms among the Omphaloidea. In these latter there are not a few examples known of those forms of pla- centa which I have called cotyledonous with incom- plete vascularization, and of this form there is not a single example among the Allantoidea. In the Canide and Felide, the highest of the Om- phaloidea, though the umbilical vesicle takes no di- rect part in the formation of the placenta, as is the case in Cheiroptera and Rodentia, it yet not only remains very voluminous to the close of gestation, but during that period increases in size with the de- velopment of the embryo, to indicate the ancient common origin of these animals with the Ichthyop- sida and the Sauropsida. In the Omphaloidea the in- timate structure is elevated and perfected in acquir- ing greater size, of which the single and discoidal placenta, though of villous structure, in the mole is a fine example, especially taken with the zonarial but a SUMMARY AND CLASSIFICATION. 29% . perfected vascular placenta in Canide and Felide. In the Allantoidea, on the contrary, the placenta ex- hibits in all the groups the simplest form of diffused placenta, and is developed in structure by localization ; and if we consider the ascending series in the genera of the different groups, we easily perceive the verifi- cation of a fact of some interest, namely, that the lowest animals in every group have the placenta of diffused form, and that in proportion as the animals in the same group rise, it always tends to become lo- calized, until it is single and discoidal in the group of Quadrumana. Modern zodlogists, having observed that in the Lemuride the placenta is diffused, have proposed to form, on this account only, a distinct order of these mammals, separating the Lemuride from the Quadru- mana, — and anthropologists have made use of this same observation to combat the phylogenetic order taught by Haeckel, which, in the process of evolution, makes the lemurs precede the monkeys. In the or- der of Quadrumana is repeated the same fact noticed in all the groups of the Adlantoidea, and the doubts of zodlogists and the observations of anthropologists lose, therefore, it appears to me, their importance. But carrying the investigations still farther it will not be difficult to discover another fact, and one of real importance to phylogeny, namely, that all living animals that have the simplest forms of placenta, whether Allantoidea or Omphaloidea, have their rep- resentative in the fossil animals found in the oldest strata of the earth; and, on the other hand, those which present the highest forms of placenta were the last to appear on the surface of the globe, — which 296 SUMMARY AND CLASSIFICATION. furnishes a link that might not be suspected between embryology and paleontology. Difficulty is met with in illowine the arrange- ment I have pointed out, when we reach the group of the Edentata, but, happily, we are not the only ones who strike on this rock. All the most distin- guished zodlogists regard these animals as forming what they call a heterogeneous group, kept together because it is not known where to place them, some being deciduate and others non-deciduate. But even in this group of animals we see the fact repeated and maintained which we have observed in all the other groups of the Allantoidea: that some, as in the ge- nus Manis, the Pangolins, have the placenta diffused ; that in others it is perfected by localization, so far as to have the highest vascular structure with lacunose ectasia of the maternal vessels, as is seen in Dasypus and in Tamandua. It may be observed that all these animals appeared very late on the earth, and I vent- ure to suggest, if, instead of repeating that the Hden- tata form a heterogeneous group, which really means nothing, we may not rather suppose that the progress- ive evolution of beings having arrived at the pro- Quadrumana, these diverged into two groups, in the one progressive, which from the Quadrumana arrived at the apes and man, in the other atavistic, tending towards the older forms of animals, in which the pla- centa exhibits an irregular and incomplete develop- ment. HISTOLOGY AND PATHOLOGY OF THE HUMAN PLACENTA. CHAPTER I. Arr pathological anatomists, especially those who have studied the morbid changes of the placenta, agree that the utmost confusion exists in this branch of medical science; the use of the microscope not having served as yet to clear up the obscurity which envelops it. This judgment, severe as it may seem, is that also of Charpentier,’ who has devoted himself to the study of placental diseases. It is certain that the few and somewhat exact observations upon the morbid changes of the placenta are either too isolated, or incomplete and defective. Such, for example, in my opinion, are the fibrous changes of the villi as taught by Robin, and the cystic myxoma described by Virchow. Some have not sufficiently considered the relations existing between the diseased portions and the surrounding anatomical parts, or they have not carefully studied the differences which these changes themselves pre- sent, according as they affect the foetal or the mater- 1 Charpentier: Maladies du Placenta et des ses Membranes. Paris. 1869, 298 HISTOLOGY AND PATHOLOGY. nal placenta, or both at once. Others have believed, with Virchow, that the pathological processes attack certain anatomical elements, when in reality the origin of the disease is entirely different. Conse- quently, if there are any exact observations, they are found mingled with others more numerous which are obscure and erroneous. _ This admitted, it has seemed to me very important to attempt special studies and investigations which may become the basis of practical and advantageous application in determining more precisely these patho- logical changes. The confused and inaccurate opin- ions which have been hitherto held, concerning the anatomical structure and development of the placenta, have certainly been the cause of many of the doubts which belong to its pathology. Having demonstrated the anatomy and physiology of the placenta, it be- comes much easier to study its diseases, and thereby to verify the observations which we have already made upon its histology and development. Nevertheless, I must confess that, notwithstanding my previous studies, in examining the various dis- eases of the placenta which have come under my observation, I have found numerous and serious diffi- culties which have prevented me from advancing in my new researches as rapidly as I have desired. These difficulties arise from two principal causes. 1. The different affections are found united in the various constituent elements of the placenta; or, rather, those which are found in one portion of the organ are different, either in character or degree, from the changes in other portions. More commonly, diseases attack simultaneously the maternal placenta OF THE HUMAN PLACENTA. 299 and the villi, without our being able to establish any limited or well-marked relations between them; as, for example, a disease of the parenchyma of the villi may be complicated with an entirely different affec- tion of the glandular organ which envelops them. 2. The same lesions, well characterized, assume different appearances and produce results dependent upon the invasion of the pathological process affect- ing the portions of the placenta during the periods of evolution, or when its development has been com- pleted. The fibrous changes of the maternal placenta will present various characteristics as they attack it, either when represented by the cells of the serotina, or when the glandular organ has been already formed. In a word, the pathological changes have and must have different appearances, according as they affect the histological elements or the organs resulting therefrom. In the midst of so many difficulties, I have not the assumption to treat of all the diseases of the placenta; some, moreover, are very rare and ex- ceptional. I shall describe the more common patho- logical changes, and shall attempt to be as precise as possible, so that my observations may at least serve to place a little in order the knowledge already gained and present a guide to the investigators of the future. The anatomical structure of the placenta and its division into the maternal and the foetal would seem to indicate the method to be followed, namely, to sep- arate the lesions of the villi from those of the gland- ular organ and placental sinuses. But this classifica- tion can only be theoretical. We must in fact describe complex pathological results. Let these be once ac- curately known, and we could easily separate them 300 HISTOLOGY AND PATHOLOGY, ETC. into their elements and give a clear idea of the lesions which affect the distinct portions of the organ. It is from these considerations that I shall classify and | describe the placental diseases which I have had an opportunity to observe. CHAPTER II. THE PATHOLOGY OF THE CHORIAL AND OF THE PLA- CENTAL VILLI. I HAVE stated above, that the imperfect knowledge which we have hitherto had in regard to the anatom- ical elements of the villi has been one of the principal causes ofthe ignorance concerning some of the changes which affect them and the confounding of others with _ those which are peculiar to the different placental por- tions. Virchow was the first to observe that the pa- renchyma of the chorial and placental villi were formed of an elementary tissue which we find abundant in the embryonic state. He called it myxoma, mucous tissue. Yet, in the case of cystic myxoma or hydatid placenta, we shall see that this eminent pathologist considered as a disease of the mucous tissue of the villi a peculiar morbid change of the epithelium which covers them. Hence, taking for guidance the obser- vations of the most illustrious authors, still we find ourselves amid uncertainties and doubts, so that it is extremely difficult to separate that which is correct from that which is not. The villi, which during the early months of preg- nancy are developed over the whole surface of the chorion, are composed of two parts: an internal or parenchymal portion, which is in direct communica- tion with the chorion, and which Robin called chorial 302 CHORIAL AND PLACENTAL VILLI. tissue and Virchow mucous tissue ; and an external portion, which is composed of an epithelial envelope entirely surrounding them. The chorial villi, which are found situated near the uterine surface at the place where evolution of the placenta will take place, increase normally in number and volume, and consti- tute the foetal portion of this organ; the others, on the contrary, are arrested in their development and become atrophied largely by fatty degeneration. Robin was the first to make this observation, and he further noticed that the villi which become atro- phied contain not only yellowish, molecular granules, but also fatty granules and free fat. We shall see, moreover, he admitted that when the production of fat in the anatomical elements modifies and dimin- ishes the nutrition of the tissues, there is established the morbid form of the placental villi, improperly des- ignated by the denomination of fatty placenta. The villi destined to enter into the formation of the placenta remain from the commencement sur- rounded by the cells of the membrana decidua, which is abundantly proliferated in that portion, which has received the name decidua serotina, to distinguish it from that part which covers the surface of the uterus and which has been called decidua vera. Now the decidua serotina and the decidua vera are at first com- posed of a single bed of cells of new formation, with this difference, that subsequently the cells of the uter- ine decidua do not proliferate, as do the cells of the serotina, in the midst of which cells the villi pene- trate. The epithelium of the villi of the placenta is perceived some time after they have been enveloped by the cells of the serotina; then, in proportion as CHORIAL AND PLACENTAL VILLI. 303 these cells, little by little, from being round, become fusiform, in order to form the membranous envelope or glandular organ of the placenta, the epithelium of the villi disappears and we distinguish upon the villi only the internal epithelium of this maternal mem- branous envelope. In several cases of abortion, the chorial villi which should normally become atrophied increase in volume and are hypertrophied. Under these circumstances, the external epithelium is retained and proliferates considerably, so that it has been mistaken for that which covers the internal surface of the envelope, fur- nished to the villi of the placenta by the modified cells of the serotina. This error has caused some to declare that the placental villi are clothed with an epithelial layer, while others have considered them as covered with a membrane. When the placenta is fully developed, if there re- main any chorial villi, they are still covered with an epithelial layer; those, on the contrary, which de- velop to form the placenta lose this envelope, and are composed only of the fundamental parenchymal tis- sue which incloses the vessels of the foetus. The ex- ternal portion of the parenchyma of the villi is found then in contact with the internal epithelium of the glandular organ which surrounds them. The parenchyma or mucous tissue of the villi is composed of two parts ; one homogeneous, gelatinous, transparent, in which is inclosed the other, formed of quite large, rounded nucleated cells. In the normal condition, the intimate structure of the parenchyma does not change during the whole period of gestation, only at a certain time the vascular loop is developed, 304 CHORIAL AND PLACENTAL VILLI. which is wanting at first, but which, when once formed, remains until the end of pregnancy. It is precisely in these elements of the chorial and placen- tal villi that we establish the pathological changes occurring in the foetal portion of the placenta. CHAPTER II. HYPERTROPHY OF THE CHORIAL VILLI OR MYXOMA OF VIRCHOW. VircHow was the first to observe that the paren- chyma of the chorial villi, called endochorion to dis- tinguish it from the exterior epithelial layer named exchorion, is formed of mucous tissue which is found in abundance in the embryo during the early period of gestation. This tissue has the physical character- istics of mucus; chemical analysis has shown that it contains mucine, and it is a gelatinous substance, in which are suspended cells. From these observations, Virchow inferred that the hypertrophy of the chorial villi, so frequent in the aborted ovum, is an hypertrophy of the normal tissue of their parenchyma ; this change, having reached a high degree, gives place to the morbid form called by Wedl and Robin hydropsie of the villi, or hydatid placenta by earlier authors. Thus the two diseases, hypertrophied villi and hydatid placenta, are simply two degrees of an exaggerated development of the fundamental tissue which constitute the villi. Consequently Virchow agrees with Wedl and Robin as to the seat of the pathological change, but includes the two diseases under the same name, myxoma of the chorial villi. My own observations do not contradict in general 20 206 CHORIAL VILLI OR MYXOMA OF VIRCHOW. those of Virchow, they even confirm them in certain points, but in others are quite different. In order to render clear this difference, I shall treat separately myxoma of the chorial villi and hydatid placenta. It is certain, that in the greater number of cases the hypertrophy of the chorial villi represent, as Wedl and Virchow have shown, an early stage of hydatid pla- centa. In fact, we know that in certain aborted hu- man ova a large part of the exterior surface of the chorion is covered with long, large, arborescent villi which are precisely the same that must become atro- phied and disappear during the development of preg- nancy. > By careful examination, we see that the principal trunk of these villi proceeds from the external surface of the chorion with which 1t is in close relation; then it divides into three or four branches, which subdivide until they form very thin extremities, a little swollen at the end. The transverse diameter of the trunk near the chorion is from twelve to fifteen hundredths millimetres in its ramifications ; it diminishes to ten, eight, four, until at its extremity it measures only two or even one hundredth of a millimetre. Near the base of the trunk, the diminution of the diameter takes place with certain regularity, but this is not true in its ramifications. In a single branch of four to six hundredths of a millimetre in diameter, we find sometimes circumscribed enlargements which at- tain to twelve or even fourteen hundredths. The actual length of the hypertrophied villi which I have measured varied from eighteen to twenty-five milli- metres. By the aid of sufficient magnifying power, we de- CHORIAL VILLI OR MYXOMA OF VIRCHOW. 307 termine that the villi are formed of two parts united with each other, but yet distinct; an external epithe- lial layer; and the stroma, or internal, homogeneous, transparent substance, in the midst of which, by the use of carmine, we observe rounded or oval nuclei ar- ranged in longitudinal series. The external surface of the ramifications of the vill is covered with numerous pyriform appendages, irreg- ularly pedunculated; these appendages are some- times ovoid or triangular. When they are united, or developed one upon another, there results the most varied forms. These morbid productions, especially when in the state of formation, are developed by pro- liferation of the external epithelial layer. Muller! had already declared that these morbid changes commence with an enlargement of the exter- nal envelope of the villi, or exochorion, and that later they give place to internal cavities which afterward take the form of vesicles, analogous to those of the hydatid placenta, and are covered with a fibrous layer furnished by the endochorion, or interior portion of the villi. ) Virchow * agreed with Miiller that the epithelium is the point of departure of the production of the cysts, but he adds, that, in order to change them into vesicles, the basic substance of the villi must penetrate into the new epithelial product; that this is formed by buds of the parenchyma, and that the peculiar trans- formation of the fluid contained in the vesicles of the hydatid placenta takes place in the substance of the buds which penetrate into the epithelium. ' Thus, according to this author, the external wall of 1 Archives, 1843, 2 Krank. Geschw. 1 B. s. 409. 308 CHORIAL VILLI OR MYXOMA OF VIRCHOW. the vesicles of fibrous appearance is always formed of primitive epithelial cells which constitute the numer- ous pedunculated appendages of the exterior surface of the hypertrophied villi. It is certain, that examining with the microscope the hypertrophied chorial villi we see evidence of what Miiller affirmed, namely, that the morbid change is caused by the proliferation or enlargement of the epithelium of the villi. But we observe, also, that the surface of the small pyriform portions, which represent, in the embryonic state, the pedunculated vesicles of the hydatid pla- centa, produce others equally pedicellated, a few of which show a small cavity in their interior. These observations, which may be easily verified, demonstrate the error in the doctrines of Miiller and Virchow. ‘The internal substance of the villi cannot penetrate by pedicles, as Miiller would have us sup- pose, and thus, in a way unknown to us, envelop the globular portion of the pyriform appendices and fur- nish to them the external fibrous membrane, when the fluid which they contain changes them into ves- icles. Nor can we agree with Virchow, that the prolifera- tions of the mucous tissue penetrate into the new secondary and tertiary products which shall be devel- oped from the epithelium of the villi. The trace of an internal cavity in some of the thin epithelial prod- ucts indicates already the presence of a liquid which has nothing in common with the mucous tissue, or fundamental substance of the villi. The formation of cavities, filled with a hyaline liquid, was observed by Wedl! not only in the epi- 1 Gundziige der Pathologischen Histologie, Wien, 1854, p. 202. CHORIAL VILLI OR MYXOMA OF VIRCHOW. 309 thelial cells of the villi, but also in the epithelial prod- ucts which I have described, and even in the paren- chyma of the villi. Virchow confirmed this observation of Wedl and called the transparent cavities physalides and the cells affected with a similar change physalifores. Further minute researches upon the hydatid pla- centa and upon the structure of the external mem- brane of the vesicles demonstrate that the hypertro- phy of the chorial villi and the microscopical, pyriform | new-formations which we find in them must really be regarded as an early stage of this disease. They also prove that the extremely small pyriform productions are at first an epithelial new formation of the villi, and that they do not change, even when the disease has reached its last stage of development, but that these new productions have been replaced by large vesicles of the hydatid placenta. For the present, I shall content myself with having placed beyond doubt that the pedunculated new ex- crescences, various in form, whether containing liquid or not, are a morbid change, due exclusively to the epithelium of the chorial villi, and that the pa- renchyma of these villi takes no part in their forma- tion. In conclusion, what Miller and Virchow affirmed concerning their epithelial origin is demonstrated ; but, on the other hand, it becomes manifest that the parenchyma of the villi do not aid in their formation, either in the external membrane of the hydatid cysts, or in the liquid which they contain. This will be still more clearly seen by the examination of the hy- datid placenta. CHAPTER IV. HYDATID PLACENTA. Tue study of the hydatid placenta has occupied anatomists from Aristotle to Virchow. I shall not cite the opinions of each of them. Virchow has pointed them out in his Pathology of Tumors, and Charpen- tier has treated of them at length in his recent work. I will only remark that both have united in stating that there results only one clear fact from the ex- amination of these different opinions, namely, that there is a constant contradiction between the various authors. Virchow recognized the cause of these contradic-. | tions in the imperfect knowledge that exists concern- ing the structure of the chorial villi, or, as he himself admitted, an identity of structure between the villi which become atrophied and disappear during the progress of pregnancy, and the villi which constitute the foetal placenta; he has fallen also into the same mistake which he recognizes in his predecessors and has sanctioned some doubtful observations. Charpentier has, so to speak, formed, from various contradictory doctrines, a synthesis, by means of which he reduced to two general ideas the ruling opinions upon the genesis and development of the hydatid placenta. Some considered this simply a disease of the de- HYDATID PLACENTA. 311 cidua, others believed it consisted in a change of the parenchyma, whether it was a dropsy of the villi, as’ Wedl and Robin maintained, or an exaggerated de- velopment of the normal mucous tissue as taught by Virchow. To-day it is generally admitted that the hydatid placenta is in some way an exclusive product of the chorial villi. Ancelet, however, in 1868, re- turned to the ancient opinion and maintained that the hydatid placenta was a disease of the decidua.’ In reply it was urged that he committed an evident error, since the most complete and repeated observa- tions had placed beyond doubt that the disease had . its beginning in the chorial villi? By more careful study, I have succeeded in demon- strating the genesis of the hydatid placenta in the hypertrophy of the chorial villi, but this is not suffi- cient to exclude an entirely different method of pro- duction of the same disease. The exclusive doctrine of Virchow does not annul the observations of those who affirm that they have seen the grape-like vesicles | suspended from a membrane adherent to the uterine cavity, which signifies that this membrane was not the chorion, and that the vesicles were not diseased chorial villi. I have been unable in my own observa- tions to solve this delicate question, but, more than once, I have seen the same disease, which is consid- ered as a primitive form of hydatid placenta, when it occurs upon the chorial villi, attack the membrane of the placental villi which we cannot mistake for the epithelium of the chorial villi. I can therefore affirm, that if we observe a slight degree of myxoma in the hypertrophied chorial villi, 1 Gazette des Hopitaux. 2 Charpentier, op. cit. 32 HYDATID PLACENTA. we also meet it in the foetal villi of the interior of the placenta, so that, if the observation of the hydatid placenta arising from the decidua is wanting, we have no reason to reject the possibility of the fact, since we have really been able to notice its genesis. The rea- son, as I believe, why such a disease of the placental villi has not yet been demonstrated comes from the confusion which has been made concerning the struc- ture of the placental villi in their normal condition, and the structure of the chorial villi which have be- come diseased and hypertrophied instead of atrophied. This uncertainty must lead to contradictions upon the intimate structure of the villi which constitute the pathological fact under discussion. So far as we have given attention to it, we see that some have referred the observations made upon the hypertrophied chorial villi to the normal placental villi; while others, on the contrary, have referred the observations made upon these normal placental villi to the hypertrophied cho- rial villi. ° By showing the really twofold origin of the vesicles constituting the hydatid placenta, I shall be able to. treat with much more clearness myxoma of the hy- ‘pertrophied chorial villi and myxoma of the placental ‘villi. In the first case, I have stated that the disease ‘originates in a proliferation of the epithelium which «covers and is a part of the chorial villi; in the other ‘case, the disease begins upon the external envelope of the villi, which belongs to and is a part of the gland- ular maternal organ. There results, consequently, two kinds of myxoma, ‘at least in the beginning: myxoma of the chorial ‘villi, as Virchow termed it, and myxoma of the pla- HYDATID PLACENTA. 313 cental villi. Therefore, in order to avoid errors and contradictions upon the origin of hydatid placenta, we must determine which are the villi that form the subject of observation. Now, I shall treat first of myxoma of the chorial villi in an advanced stage, either of the placenta or of the hydatid mole, which I described in its early growth, when speaking of hy- pertrophied chorial villi; then I shall occupy myself with myxoma of the serotina, which I have stated has been studied in its origin in the placental villi. Myxoma of the chorial villi,.when it has reached the stage which we call placental or hydatid mole, constitutes a mass, more or less considerable, of pe- dunculated grape-shaped vesicles of various dimen- sions from the size of an hazel-nut to that of a very small granule scarcely perceptible to the naked eye. Their form is ovoid, spherical, or pyriform. Cayla! observed some of very singular form. He saw with the naked eye, in a hydatid placenta, the various forms of the vesicles which I have found in the hypertro- phied villi, and which I have studied microscopically. The hydatid vésicles are seen first at the place where the trunk of the villi branches; in its ramifi- cations we find some irregular swellings of the pedi- cles. Hach vesicle has its pedicle, but not every pedicle buds at the ramifications which proceed from a common branch, since from the external surface of the larger number of these vesicles there starts out others much smaller and equally pedicellated. However, Haller had already excluded such an idea, by stating that the vesicles originated from one another. In two hydatid placenta which I have exam- 1 Thèse Inaugurale. Paris. 1849. 314 HYDATID PLACENTA. ined, I was able to prove, contrary to what Virchow had affirmed, that the vesicles not only proliferate from those which are the largest, but also that they — are frequently larger than those from which they have origin. From the surface of little vesicles I have seen orig- inate pedicles which supported larger ones, and these still others of different volume. In some places I have even noticed that the terminal vesicles were the largest. This observation Ancelet also made, and he found terminal vesicles the size of a pigeon’s egg. In these reticulated clusters of vesicles we must consider the pedicle, the membrane, and the liquid contained therein. The pedicles are of two kinds, those which are formed by the trunks and branches of the villi, and those which are developed from the external surface of other vesicles. The first are com- posed of the external epithelial layer and of the. fundamental tissue of the villi, or mucous tissue of Virchow, and which Robin called chorial tissue on account of its identity with the tissue of the chorion. In discussing hypertrophy of the villi we have seen that the rudimentary vesicles produce other pedi- celled vesicles, and these like their pedicles are an epithelial proliferation. This singular change was observed by Haller, Cayla, and others. The pedicles were generally regarded as solid, and only in rare exceptions were they recognized as vesicular, at least in part. The vesicles, whatever may be their rela- tions, are always filled with a colorless, slightly gluey liquid which contains albumen coagulable in alcohol. . + The reddish color which the liquid sometimes pre- sents has been attributed by Robin to a kind of im- HYDATID PLACENTA. 315 bibition of the coloring matter of the blood, arising from the clots which are often found in the mass of the vesicles. There is no confirmed opinion concerning the struc- ture of the vesicular membrane. According to Robin and Cayla, it is formed of the tissue of the chorion ; after Pelvet! it is composed simply of molecular gran- ules of fibrous character; Louis? believes that the fusiform cells, which constitute it, contain an abnormal quantity of fatty granules; Ancelet® maintains that it is formed of two very thin but distinct and separa- ble membranes. He adds, there is no communication between them, except in case the vesicle springs di- rectly from the surface of another vesicle. Under such circumstances he succeeded sometimes in sepa- rating the vesicles without emptying them. When they are separated by a conical pedicle a part of the pedicle is permeable to the liquid, but the other por- tion being obliterated we can never make the liquid pass from one cyst into another: however, Skròkius and Vallisnieri have observed a complete communi- cation. From my own observations I have reason to ques- tion the correctness of this statement, having never been able to find it even in the pedicle; we can, how- ever, admit it as possible, considering that the internal layer of the pedicles is composed of the same ele- ments which are transformed into mucous fluid in the interior of the vesicles, and that the same transforma- tion can consequently extend itself into the interior of the pedicles. È 1 Bulletin de la Société Anatomique. 1865. 2 Charpentier, op. cit. 3 Gazette des Hòpitaux. 1868. 316 HYDATID PLACENTA. I have demonstrated elsewhere that the vesicles and the pedicles are a new pathological change of the epithelium of the chorial villi. No one hitherto has indicated this fact, however easy it may be to estab- lish it even when these changes have arrived at an advanced stage of development in the hydatid pla- centa. By detaching in the ordinary way the external layers of a vesicle, especially if it has remained some time in alcohol, and examining with the microscope, we perceive immediately that the resemblance of their structure with that of the fibrous tissue of the chorion — is only an apparent one. By the process of imbibition we readily observe that the vesicle is composed of various epithelial lay- ers, and that proliferation occurs upon the superficial layer in pyriform appendages as I have shown in hypertrophied chorial villi. In short, by the aid of the microscope we see upon the surface of the vesi- cles of an hydatid placenta in process of formation the same phenomena which we distinguish with the naked eye when the disease has reached its complete development. The changes and destruction of the cells in the deeper layers of the vesicles explains thus not only the increase in volume, but also the constant property of the fluid contained in them. The cells of the ped- icles, on the contrary, rarely undergo such a trans- formation ; oftener they assume the characteristics of a tissue similar to fibrous tissue which constitutes a kind of little central cord of homogeneous transparent substance ; in the centre of which, by the use of car- mine, we may cinaguie oblong nuclei blended with each other. HYDATID PLACENTA. SET Cayla found, in the fluid of the vesicles, cells which he thought were of a different kind, on account of their diversity of form. In reality they represent only different degrees of the change which they must undergo in being transformed into liquid. Cayla was unacquainted with the elementary structure of the walls of the vesicles. He could not, therefore, under- stand the origin of the cells which he found in the vesicular liquid. The formation of vesicles of the hydatid placenta from the epithelium of the chorial villi, the purely epithelial structure of the vesicular membrane and the proliferation of their exterior surface, without fre- quent communication with their internal cavity, dem- onstrate clearly, in my opinion, that the doctrine of © Virchow generally adopted, upon the subject of hy- datid placenta, is not confirmed by observation. Wedl, Robin, and others, regarding the anatomical observation as a fact, considered this disease an hy- dropsy or liquid degeneration of the villi. : Wedl de- scribed and represented, Fig. 32 in his “ Pathological Histology,” a portion of the villi containing hyaline fluid analogous to that which I have described in the epithelial neoplasms of the hypertrophied villi. Virchow declared that it was an hyperplasia of the preéxisting mucous tissue; with this he settled the question, yet he agreed with Wedl and Robin, in locating the point of attack of the disease in the pa- renchyma of the villi. I consider this affirmation of Virchow erroneous. I would even renounce the term myxoma, keeping it for the disease of the villi, of which I shall soon treat. However, opposed as I am to neologisms, I prefer 318 HYDATID PLACENTA. to retain the denomination which he has given to hydatid placenta, confessing at the same time that, while I accept the name, I cannot admit its signifi-- cation in its pathogeny. In order to justify my ob- jections to the doctrine of this real prince of pathol- ogy, I quote an observation as easy to repeat as it is convincing. The observation was made upon a series of vesicles from an hydatid placenta detached from the trunk or pedicle produced by the external membrane of an- other vesicle. The series were united by a filament or common pedicle. The length of the pedicle comprised be- tween two vesicles varied from three to eight milli- metres; they were from a twelfth to a fifteenth hun- dredth of a millimetre in their transverse diameters. They increased a little nearer the vesicles, but not in proportion to the size of the vesicles which had a transverse diameter from one to ten millimetres. The change of the pedicle from the form of a cord to the globular shape of the vesicles was very rapid; these last, emptied of their contents, showed plainly the oval form. Examining this series microscopically, we ob- serve that the pedicles and the external surface of the vesicles are covered with epithelium, and that the epithelium of the pedicles and of the external surface of the vesicles takes its origin in the pedicellated, pyriform corpuscles, identical with those of the hy- pertrophied villi. I have already elsewhere described the structure of the anatomical elements of the cen- tral portion of the pedicles of which we find no trace in the internal membrane of the vesicle. The inter- nal cellular elements of these vesicles are transformed HYDATID PLACENTA. — 319 into liquid, while the external layers proliferate and produce other vesicles. Thus, by means of this simple preparation, we ob- serve intermediate vesicles having at the two poles pedicles which are in connection ‘only with the epi- thelium of other vesicles, so that, by this fact alone, the presence of the parenchyma of the villi in their interior is demonstrated as absolutely impossible. If these observations are interesting in regard to the anatomical knowledge of the placenta or hydatid mole, they will be of far greater profit to the histolo- gist, who will thus be able to establish a new scien- tific fact, namely, the progressive metamorphosis of the external epithelial layers, at the same time with the retrogressive metamorphosis of the internal layer. CHAPTER V. | | MYXOMA OF THE SEROTINA OR OF THE GLANDULAR OR- | GAN WHICH ENVELOPS THE PLACENTAL VILLI. WirHour referring to ancient authors, who consid- | ered the hydatid placenta as a disease of the decidua, iù I will notice that Depaul! declared he had observed that the vesicles were in relation with the internal surface of the decidua. Martin, the younger, quoted by Ancelet, stated he had found a considerable num- |A ber of grape-shaped vesicles, as many upon the sur- | face as in the interior of a very large placenta. Pelvet? saw an hydatid mole still shut up in the uterus, and he maintained that the vesicles were at- tached at their extremity to the internal uterine wall. Other observations are not wanting which, though less positive, allow us to suppose that the membrane, | which we regard as the point from which the vesicles | proceed, is the decidua rather than the chorion. An- celet,? who was the last to report these observations, stated that the vesicles hung suspended in the uterine cavity, being attached to a membrane which clothed in part the wall of the uterus and in part the mem- branes of the ovum. He therefore concluded that the vesicles proceeded from the uterine and reflected de- cidua, and he endeavored to explain the fact by sup- 1 Mouvement Médicale, 1868. Lecons recueilles par M. de Soire. 2 Bulletin de la Société Anatomique. Paris, 1865. 8 Gazette des Hépitaux, 1868. MYXOMA OF THE SEROTINA. SZ posing that the liquid secreted by the utricular glands pushed before it the superficial layer of the decidua and was covered by it. He affirmed that Sirelius had already demonstrated that, in the normal condition, a layer of this membrane envelops the placental villi and serves as a sheath to them. He seeks in this way to support this erroneous opinion by an observation which he had imperfectly comprehended. The false interpretation does not however destroy the fact he had observed, and now it is established that the ve- sicular clusters are suspended in the interior of the uterus and that they originate from a membrane ad- herent to the uterine surface. This fact has but one interpretation for those who believe that the vesicles of the hydatid placenta are exclusively formed from the chorial villi. In my previous observations upon the structure of the placenta, I demonstrated that the cells of the ser- ‘ otina in the human species furnish a complete bed for the villi of the foetal placenta, and I argued, from numerous observations in comparative anatomy, that the external membrane of the placental villi repre- sents the glandular organ of the maternal portion which we find, in some animals, under more simple and more characteristic forms. At this time I was not aware of the observations of Sirelius and, conse- quently, could not quote them. I am desirous now to fill up the gap and add at the same time that the anatomist of Helsingsfors had likewise pointed out the fundamental physiological idea of my own studies. Sirelius* had already observed that, when the hu- 1 Om Placenta dass utvecklung och behandlung. 1861. Helsingsfor: È Archives de Toxicologie, April, 1876. 21 322 |. MYXOMA OF THE SEROTINA. man ovum penetrates into the uterus, failing in ves- sels and being enveloped by the cellular layer of the decidua, the absorption of the nutritive fluids must necessarily take place from this envelope. Afterward, | the external cellular layer of the placental villi, not | being as we have stated epithelial, but furnished by the decidua, it follows that the maternal blood and IÙ the vessels of the foetal villi are separated by cellular | . layers and by the parenchyma of the villi which cov- i ers the vessels, through which the nutritive fluid must traverse to arrive at the foetal blood. He added that all these parts must have a greater | or less influence upon the facility of assimilation of Il the liquids which traverse them, and that we must admit an analogy between the cellular layers of the serotina which envelop the villi and the glandular organs. Before the demonstration of my observations, Sirelius had really pointed out the relation of the foe- tal villi with the cells of the serotina during the early period of gestation, the external envelope furnished later to the same villi by these cells of the serotina, and the idea of a maternal organ, analogous to the | glandular organs, for explaining the nutrition of the ii foetus. No one had continued or noticed the studies | of Sirelius ; however, the General Archives of Medi- cine published a résumé of these in 1861, and Ance- let alone made use of them for his interpretation. Langhaus, who has very recently furnished a spe- cial treatise upon the human placenta, had no knowl- edge of the works of Sirelius or my own. He gives, as an entirely new observation, the intimate and close 1 Archiv fiir Gynecologie. Berlin, 1870. Zur Kenntniss des Mensli- chen Placenta. MYXOMA OF THE SEROTINA. 328 union of some foetal villi with the serotina, which he regarded as the maternal portion of the placenta. Finally, these various observations confirm what I have stated and now repeat. All the chorial villi are in the beginning of pregnancy covered with epithe- lium. This epithelium is preserved even when the villi are attacked with hypertrophy and myxoma. There is no necessity of confounding, as has been done until now, the external epithelium of the healthy or diseased chorial villi with the external envelope of the placental villi arising from the cells of the sero- tina. I shall now describe myxoma of the serotina. The intimate relation of the placental villi with the de- cidua and the resemblance of the cells of the serotina to those of the same villi have caused the epithelium of the chorial villi to be mistaken for the cellular en- velope which’ the serotina furnishes to the placental villi. Some consider the two envelopes as products of the serotina. Schroeder Van-der-Kolk confirmed the observation of Sirelius relative to the placental villi and regarded them as proceeding from the decidua, so that the placenta was wholly an elaboration from the mother. Without repeating my observations concerning the envelope which the cells of the serotina furnish to the placental villi, in order to constitute the gland- ular organ, I have quoted the observations of other anatomists who confirm the fact that the layer of cells of the serotina which covers the placental villi ought not to be mistaken for the epithelium of the chorial villi. A single remark is sufficient to prove this. The extremities of the placental villi, when 324 MYXOMA OF THE SEROTINA. completely developed, always penetrate deeply into the cells of the serotina; their ramifications alone re- main free and appear to swim in the blood of the la- cune; the chorial villi, on the contrary, are entirely free, and have only the relation of contact with. the decidua. In other words, the chorial villi are never found amid the cells of the decidua. The placental villi are constantly met with in that portion of the decidua, called serotina. It is their anatomical condition, and materially indispensable for their complete develop- ment. A placenta which I carefully examined, and from sections of which I made microscopic drawings, be- longed to a foetus aborted from the third to the fourth month. It had every normal appearance; both upon the interior and exterior its development was complete. The so-called placental parenchyma was composed of a complicated network of villi in the midst of lacunz limited upon the one side by the chorion, and upon the other by the cells of the sero- tina. With the microscope, we perceived upon the pedicles and the branches of the villi irregular swell- ings, formed by a layer of cells of the serotina which constitutes the enveloping membrane. In the cells, there occurred an arrest of develop- ment of the evolving process of the glandular organ and a proliferation of the little pedicelled bodies com- monly pyriform; a few of which, the physalides of Virchow, contain some liquid, as we have already ob- served in the epithelial proliferations of the villi of the hypertrophied chorion. The parenchyma of the villi was attacked with atrophy and fibrous transfor- MYXOMA OF THE SEROTINA. BIAS, ‘mation during the early stage of its development. This change, complicated by the separating of the en- veloping membrane, shows clearly the independence of the little pyriform bodies and of their contents from the parenchyma of the villi. In conclusion, it is clearly demonstrated by the preceding observations that, in reality, the denom- ination myxoma, given by Virchow to this disease of the chorial villi, is incorrect. It is moreover proved that hydatid placenta may have its origin in the cells of the serotina instead of having it exclusively in the chorial villi. We can at least affirm that the first pathological form of hydatid placenta which we ob- serve upon the chorial villi may also be seen upon the placental villi. CHAPTER VI. CELLULAR HYPERPLASIA AND HYPERTROPHY OF THE PARENCHYMA OF ‘THE PLACENTAL VILLI. (FATTY DEGENERATION OF THE PLACENTA.) THE disease of the placental villi which I designate | | under the name hyperplasia or cellular hypertrophy | of their parenchyma is that which pathologists have | hitherto denominated fatty degeneration of the pla- centa. This last name, the resemblance of the dis- ease to fibroma and to the obliteration of the ves- | sels of the villi, the relations which observers have wished to establish between it and placental heemor- rhage, have been the cause of the greatest confu- sion. The perplexity we encounter in treating separately of each disease is almost insurmountable. I shall give | | as proof of it simply the opinion of Charpentier who i affirms that the placenta is always attacked by only | one morbid change. In conclusion, writes he, the le- sion of the placenta is one; at first there is a fatty de- | generation and obliteration of the villi, then a bloody | extravasation and successive transformations of the I effused blood. These two lesions are, according to his opinion, only two successive degrees of one single and identical process. In the discussion of placental hemorrhage I shall treat more at length the conditions which Charpentier PATHOLOGY OF THE PLACENTAL VILLI. 327 especially emphasizes to be a rule of morbid unity. But I cannot avoid touching now this question, since the observations of the greater number of pathologists relate almost without distinction to fatty degenera- tion and hemorrhage. Generally we believe that the fatty degeneration of modern authors corresponds with many of the lesions which the ancients have called induration or encephaloid, scirrhous, cancerous, or tuberculous de- generation of the placenta. Indeed, fatty degenera- tion presents itself under the form of grayish or whitish masses, harder and more compact than the placental tissue in its normal state. These masses do not separate into filaments. They may occupy a part or the whole of a cotyledon; the fourth, half, or whole of the placenta. These characteristics justify to a certain extent the ancient denominations, but there are wanting the necessary facts to establish a sure diagnosis, and we cannot deny that thrombus and fibrous transformations have been mistaken for in- durations or scirrhus. ) Hitherto all anatomists have regarded the scirrhous nodules and fatty masses as constantly due to bloody effusion. They have attributed to the clot which’ surrounds the villi the suspension of their internal, circulation and the obliteration of the vessels. The yellowish color and lardaceous consistency of the dis- eased portions were the result of the slow transfor- mation of the elements of the blood, especially of the fibrine. Robin demonstrated the uncertainty of these opinions. He confirmed by his observations that the yellow induration of the placenta is not the result of the effusion of the blood; we never find there its 398 PATHOLOGY OF THE PLACENTAL VILLI. characteristic elements, globules, fibrine, crystals of hematoidin. He concluded, therefore, that the dis- ease consisted really in a fatty degeneration of the villi, adding that if we were ignorant of the morbid process we might be allowed to suppose that it was analogous to that which has for its result the normal disappearance of the villi of the chorion. In conclu- sion, the question under discussion resolves itself into this: Is there a true atrophied obliteration of the ca- pillary vessels of the foetus, complicated with thicken- ing of the cellular tissue which surrounds them, and fatty granular infiltration of the fibrous membrane furnished by the chorion? In consequence of these opinions Robin adopted the denomination fibro-fatty degeneration. The pathological fact thus determined is very ob- scure. According to Robin the fatty degeneration does not take place in the parenchyma of the villi, in which, however, he establishes the obliteration of the vessels, but rather in the fibrous membrane which envelops them, and which he believes proceeds from the chorion and not from the serotina. The cellular tissue of the parenchyma may be attacked with thick- ening. We therefore believe that he wished to point out the anatomical lesion of the mucous tissue of the villi which I described, if the term cellular tissue has not in the technical language of these later years a different signification from its ordinary use. His own expressions, moreover, prevent us from knowing ex- actly what he comprehended. Nevertheless, Barnes! and Robin? were the first to occupy themselves particularly with this lesion, 1 The Lancet. 1853. 2 Société de Biologie. 1854. PATHOLOGY OF THE PLACENTAL VILLI. 329 and to call it fatty change or fibro-fatty degeneration. Under this name they described a lesion of which the microscopical characteristics correspond in every re- spect with those of morbid placenta, in which with the microscope I observed the hyperplasia and cellu- lar hypertrophy of the parenchyma of the foetal villi, simple or complicated with central vascular oblitera- tion and lesion of the glandular organ. Barnes stated that placentze attacked with this dis- ease show the maternal surface deeply furrowed, with a coloration similar to that of the brain; the disease attacks one or several cotyledons, and the diseased lobes have the pale yellowish color of fat, the bottom of the grooves is red, but when all the cotyledons are affected with the disease the placenta appears blood- less. By means of vertical section we perceive more distinctly the yellow fatty matter which is found upon the side of the foetal surface, and although there re- mains some bloody coloration, we see no longer the characteristic appearance of the normal placental tis- sue. The miscroscopical observations of this author are too vague to be appreciated. He states that we can establish a very marked change of the villi near the uterine surface, but that there is none of it in the normal condition; in the most compact lobes the villi are fragile and deformed, the vessels have lost their distinctness of outline, and the varicosities of the vas- cular walls are greater and they contain more gran- ules than ordinarily. Robin added, that in some placentz the cotyledons are found plainly separated from each other by deep furrows, that the uterine surface shows salient lobes, distinct for each cotyledon, that they are harder than 830 PATHOLOGY OF THE PLACENTAL VILLI the normal tissue, friable, and susceptible of filamen- tary laceration. The diseased portions have a gray or yellowish gray color, sometimes yellowish white ; they are less humid than the healthy ones. Bringing the parts into a normal relationship, the morbid tissue retakes gradually its natural color, but always remains more compact, less red, and less humid. The diseased portions are composed of villi obliterated by cellular tissue, and only a few of these contain fatty granules. Charpentier, having repeated the words of Robin, de- clares that he has clearly described, under the name of obliteration, the true fibrous transformation of the villi, one of the two morbid forms of fatty placenta. There remains some uncertainty as to the precise signification he gives to the words, “ obliterated by cellular tissue.” Robin declared that he had found fatty granulations in the two morbid forms, and it was for this reason he gave to them the denomination of fibro-fatty degen- eration, which has been generally accepted. He re- marked, however, that the presence of fat was not established in both cases, and that in the whitest por- tions there were ramifications of villi which contained not a trace of fatty granulation. He concluded that the fatty deposits were a complication of the oblit- eration of the villi, and that the name fatty degenera- tion, given to placenta attacked with this disease, was not entirely correct. Robin thus pointed out the way to follow ulteriorly by designating under one common name two forms of lesion of the parenchyma of the villi; the fibrous transformation and hyperplasia and cellular hypertrophy. Unfortunately those who have followed him have increased the confusion, so that PATHOLOGY OF THE PLACENTAL VILLI. Doll many no longer distinguish placental hemorrhage from the disease called fatty degeneration. Charpentier relates the opinion given by Robin, adding, that it is difficult to be clearer or more ex- plicit in the description of the placental change called fibro-fatty degeneration. It resembles in no respect, says he, that disease .which Jacquemier and some others have described under the name placental apo- plexy, but the distinction between the two diseases is not as easy as one would think ; there are cases where we meet the two lesions in the same placenta. The most complicated observation is that which Hiffelsein and Laboulbène communicated to the Society of Bi- ology, in 1865, as fibro-fatty degeneration of the placenta. They stated, categorically, that placental apoplexy was found associated with fibrous oblitera- tion of the villi, thus falling again into the error which consists in mistaking vascular obliteration and fibrous transformation for cellular hypertrophy of the parenchyma of the villi, forgetting that Robin had designated the two diseases as two forms of fatty de- generation. Druitt? and some others have considered fatty degeneration of the villi as the normal condition of the placenta at the end of pregnancy, because of the partial cessation of the placental functions when the development of the foetus is complete. If the disease takes place during the early months of gesta- tion it occasions probably a deficiency of the nutritive elements which causes the death of the foetus. Ob- stetricians, In fact, have observed that pregnancy may reach full term notwithstanding the fatty degenera- 1 The Lancet: On Degeneration of the Placenta at the End of Preg- nancy. 1853. 932 PATHOLOGY OF THE PLACENTAL VILLI. tion of considerable portions of the placenta. I have . myself seen such instances, but in the most severe cases the foetus was badly nourished, and had even. perished some days before delivery. Notwithstanding this, it remains undisputed that the foetus had lived and been nourished much better than would have been supposed from the great changes which aecom- pany always the obliteration of the vessels of the villi. | Charpentier attempted to explain the phenomenon by admitting that fatty degeneration may attack nor- mally the chorial vill. I think this signifies nothing. The function of the chorial villi is not the same as that ofthe placental villi, since the latter are destined to nourish the foetus and the former to early become atrophied. It seems to me more probable that the villi diseased from hyperplasia and cellular hypertrophy, before and even after their vascularization, continue to perform their functions more or less perfectly, as do the villi not vascularized during the early months of preg- nancy. This imperfect function, added to that of the healthy portions, suffice probably for the nutrition of the foetus. All depends consequently upon the pre- ponderance of the healthy over the diseased portions. When the latter are pronounced, foetal nutrition must necessarily become more or less defective. The preponderance and increase in volume of the cells in the mass of the mucous tissue of the villi con- stitutes the fundamental and peculiar characteristic of the disease in question. Having only examined placente thrown off by abortion, I cannot affirm whether the cellular struc- PATHOLOGY OF THE PLACENTAL VILLI. 333 ® ture of the parenchyma of the villi in the early months of pregnancy should be regarded as pathological, or normal; this last hypothesis seems to me most proba- ble. On the contrary, we must confess that the lesion is more common in the early period of pregnancy, than has been supposed and that the villi deeply sit- uated in the cells of the serotina do not allow us, from superficial examination, to perceive the disease. The exclusive cellular structure of the parenchyma of the villi is, I believe, the normal condition of their primi- tive development; consequently I do not think the preponderance of cells sufficient to characterize the disease, but that it must be attended with an increase in volume which is wanting in very young placental villi. When we observe the lesion in the fully developed placente, and can determine by comparison of the healthy with the deceased villi, it is easy to recog- nize the disease in the mass of the parenchyma of villi, exclusively formed of cells, of different size, closely crowded together. | Notwithstanding the numerous observations of pla- cente which show the external characteristics of the so-called fatty placenta, in only one severe and com- plicated case of fibroma of the glandular organ was I able to demonstrate the traces of obliteration of the internal vessels of the villi. In another case, I found portions of the villi where the central vessels were much dilated, while in the villi of the most diseased portions, which were in greater number than the others, every vascular trace had disappeared from the centre. The dilatation of the vessels, exception- ally marked in some portions of the villi, appeared to 9394 PATHOLOGY OF THE PLACENTAL VILLI. me to be the result of the obstacle opposed to the circulation by the parts of the villi where the vessels were obliterated. This seems so much the more prob- able as the dilated villi were found near the chorion, precisely in the place where the disease was less se- vere and less extended. : We may, therefore, infer that this dilatation is only the result of the progress of the disease which at first invades and rapidly attacks the last ramifications of the villi, without extending completely to the trunks. When the traces of the obliterated vessels are visi- ble, we find the cause of the obliteration in the lateral pressure, produced by the surrounding cellular ele- ments, increased greatly, both in number and volume. We have, moreover, evident proof that this morbid form of the parenchyma of the villi may attack them even when they are perfectly developed and vascu- larized. A phenomenon worthy of remark is, the difficulty of observing in this disease the traces of the internal vessels of the villi, compared with the facility with which we discover them in the villi affected with fibrous transformation. As the diseased villi increase in size, they form com- pact masses of grayish white color, for the double rea- son that they dp not contain vessels and the mater. nal blood cannot longer circulate about them. The parenchymal cells composing the mass of the villi in- crease in number and in size in proportion to the duration and severity of the disease. The cells have always a rounded form with nuclei which one can easily render visible by the use of car- mine. In examining recent sections, I have some- PATHOLOGY OF THE PLACENTAL VILLI. 335 times found that the slightest pressure upon the cover glass was sufficient to detach the villus from its gland- ular serotinal bed. The glandular product appeared normal as well in the form of its thin membrane as in that of the inter- nal epithelial elements. I cannot account for this kind of friability, so to speak, of the maternal portion, but I think by hardening the preparations in alcohol or di chromic acid this friability would disappear. The cellular hypertrophy and hyperplasia of the villi may be complicated, as I have stated, with lesions of the maternal surrounding glandular structure. It is from this point of observation especially that I find those cases which present a complication of hypertro- phy of the villi and of fibroma of the glandular organ so interesting. A placenta of this character which I examined was expelled with a foetus of seven months, dead some days previous; it was much smaller and at the same time much thicker than in the normal con- dition, the color varied from deep red to yellow, and the foetal as well as the uterine surface was irregu- larly indented. Bustamante described, if I am not mistaken, a sim- ilar case, under the denomination of sclerosis of the placenta. However, I shall review the description which Charpentier gives of this condition. In sclero- sis, the placenta is seen in the form of a reddish, fleshy, lobulated, smooth mass, resembling the thymus gland. Uponi:section it is homogenous, compact, and separable into small lobes. The changed portion ad- heres partially to the villi of the normal part. Upon the borders of the foetal surface the placental tissue is so compressed that one can observe it in re- 330 PATHOLOGY (OF (THE “PLACENTAL Viiihig: moving the diseased portions. The mucous layer which covers the uterine surface can be removed con- trary to that which happens in the normal condition. We are unable to clearly distinguish with the micro- scope the villi of the morbid tissue, because in the section it presents a homogeneous appearance, having in the centre of the so-called lobules the little arte- rial vessels. It is composed of fibro-plastic elements regularly placed and forming concentric layers analo- gous to the vascular envelopes. The entire mass seems formed of villi closely pressed against each other without our being able to explain how it takes place. Neumann?’ described, under sclerosis of the pla- centa, a degeneration where this organ had lost its softness and sponginess because of the proliferation of the villi. These were developed in such an exagger- ated way that the placental spaces were obstructed by them; the circulation was consequently arrested and this condition modified greatly the structure of the villi. In the degenerated tracts Neumann found no trace of the placental spaces; they were filled with the villi and partitions of connective tissue which con- tained fatty and calcareous molecules. It is probable that this author, under the term sclerosis of the pla- centa, made allusion to the pathological form under discussion. However, it is very possible that, in the case under consideration, he confounded the forms of cellular hyperplasia and hypertrophy with the fibrous _ transformation of the villi, as had manifestly already been done by Robin. Microscopical examination of the diseased placenta | 1 Ueber die Sklerose der Placenta, Konig]. Med. Jahrbuch, 1860. PATHOLOGY OF THE PLACENTAL VILLI. 337 which I described above presented the villi very much thickened and the mass of the parenchyma completely formed of cells increased in volume. Only in a few villi did we observe the outline of the internal vessels; for the most part there was only a single vascular trace, that of the second vessel having disappeared. Although very rarely, the double contour was still seen in some places ; the obliterated vessels were filled with amorphous substance and with some granules of hematoidin. In such cases, the hypertrophied glandular organ forms a large fibrous envelope about each villus; in places where two villi are in contact, the external walls of the organ are interblended. The internal epithelium of the wall of the glandular organ was in part preserved, but considerably dimin- ished in size ; it had lost the ordinary oval form and was no longer granular, in some places it had even disappeared. On account of the extraordinary en- largement of the villi, the lacune remained filled with either clotted or unclotted blood. I have never been able to prove this fact in simple hyperplasia. Neumann rightly confirmed what Robin had stated, that is, that the limited portions of the placenta at- tacked with simple hyperplasia and hypertrophy are always bloodless. But this phenomenon is not suffi- ciently explained by simple increase in the size of the villi, unless we add also the proliferation of the dis- eased villi. The complication of the two phenomena allows us to understand better the nature of the pathological ‘masses which result from it. The observation that I give offers also a proof of the necessity of the prolifera- tion of the villi; notwithstanding their considerable 22 A ii ‘ 9938 PATHOLOGY OF THE PLACENTAL VILLI. - hypertrophy, some have been attacked with throm- bosis, owing to a clot of coagulated blood ; others re- tained the liquid blood, and the lacunary spaces have not disappeared. In consequence of all this and of the transformation of the parenchyma of the villi into a cellular mass, it seems to me established that the analogy between this morbid form and simple cellular hyperplasia and hypertrophy of the parenchyma of the villi is evident. However, we must not mistake one disease for the other, nor consider them as two degrees of the same disease. My microscopical observations authorize me to regard the last asa special morbid form which I shall call deformed cellular hyperplasia and hypertro- phy; I prefer this denomination to that of sclerosis of the placenta, which has already been used for des- ignating the same disease. CHAPTER VII. FIBROMA OF THE VILLI AND OF THE SEROTINA. Tue fibrous transformation of the villi of the pla- centa is a common disease. Notwithstanding this, we cannot quote an exact description, either of the dis- ease or of the changes which take place in the mu- cous tissue of the parenchyma, nor of the complica- tions which it presents in taking part in the fibrous transformation of the constituent elements of the ma- ternal placenta. Robin, we have seen, was the first to speak of fibroma of the villi, and he designated it as a form of fatty pla- centa. He wrote that in certain placenta we find one or several cotyledons, or parts of cotyledons, flattened . and harder, forming a compact mass, which is sepa- rated into fragments of a filamentary and irregular ap- pearance. The morbid tissue is composed of villi which show the fibrous obliteration in an advanced stage, that is, at the period when the fibres are crowded to- gether, so that the villi form incomplete and resist- ing cords. - In only a few did he find fatty granules. The villi, thus transformed, often adhere to each other by means of an amorphous and dense material. We must notice that Robin considered the parenchyma of the villi identical in its normal structure with the tis- sue of the chorion, which is formed of an amorphous, gray, resisting substance, rarely striated and fibrous, 340 FIBROMA OF THE VILLI. having oval nodules, disseminated in the central por- tion. Virchow, treating of pathological lesions of the pla- centa, describes a simple and diffuse form of syphi- litic endometritis, which produces very often thicken- ing and fibrous infiltrations, which lead to atrophy of the villi. These terms do not give a correct idea of the disease. However, without denying that syphilis may be the cause of it, I affirm I have several times observed the fibrous transformation ‘of the villi, under circumstances where syphilis could not be admitted. Meyer of Freyburg’ has recently described this dis- ease with more detail and precision. He states that the indurations formed by the connective tissue of the placenta develop in different parts of the placenta and thus produce different results. Sometimes, according to his view, they arise from the “ original tissue of the placenta,’ sometimes from “the interstitial tissue ’’ which is formed later. Oftener the disease commences in the oblong or round cells of the decidua, situated in the vascular tissue. This form is limited or diffuse; . by compression it leads to retraction and atrophy of the placental tissue. He believes that the disease be- gins upon the surface of the decidua serotina, produces at first a thickening, then by extending into the in- terior of the cotyledons, there results a connective tissue infiltration. In other cases the connective tis- sue proceeds from the foetal vessels, and causes an in- crease and hypertrophy of the external wall of the arteries, which, by enlarging, narrows their canal, and 1 Archives, 1861. Pathologie des tumeurs, t. ii. 2 Monatschrift fir Geburtskunde von Credé, Hecher and Martin, Ber- lin, 1868. Archives de Toxologie, Mai, 1876. FIBROMA OF THE VILLI. 341 produces irregularities of the vessels. In the first condition, it is the placenta that yields first to the dis- ease, then the foetus, and hemorrhage results. In the second, it is the foetus which is attacked first and very seriously. These observations are interesting because they prove that connective tissue transformation may at- tack the decidua serotina as well as the villi. But Meyer does not mention the process of fibrous trans- formation of the parenchyma of the villi and of the cells of the serotina, nor the complications dependent on the fibrous transformation of the external wall of the villi, that is, of the glandular organ. These lesions are often found united, and I have myself observed them in a placenta, in which I could follow the proc- ess of transformation. I shall discuss first the fibrous change of the villi, then that of the cells of the decidua serotina and of the giandular organ. The fibrous transformation of the parenchyma of the villi is frequently seen in placenta aborted about the third month of pregnancy, and even in placenta where the foetus was at full term. In this last case, the disease is always very limited ; on the contrary, in abortions at the fourth and fifth months of pregnancy, it may be very extensive, and cause the death of the foetus. The opportunity for observing the placenta of a foetus passing just beyond the ‘third month has failed me. We notice different characteristics, in ac- cordance with the period of the evolutive process of the mucous tissue of the parenchyma of the villi into fibrous tissue. In the beginning, the ovular shaped cells of the central portion of the mucous tissue become more 342 FIBROMA OF THE VILLI. elliptical, numerous, and we distinguish still upon the surface the basic substance, which acquires a more solid appearance and is almost vitreous. I have several times seen this morbid form in which the central cells were few and rounded, and I am dis- posed to consider it not as an early stage of fibrous transformation, but rather as a special morbid form of the parenchyma of the villi which I would call hyalin transformation, because the cells of the paren- chyma of the villi, thus changed, are very rare and the transparent amorphous element is abundant in it. Wedl,’ it seems, found this morbid form in a very advanced stage. In Fig. 32 of his work, he repre- sents a villi containing a fluid which he called hya- lin and which demonstrated a dropsical degeneration. He states that the villi had near their extremities a swelling which contained liquid ; the external epithe- lium was easily seen, and it was double its normal size. The trunks, which were not dilated by the liq- uid, were attacked with fatty degeneration. I have never made an analogous observation ; however, com- paring what I have just reported with that which Wedl observed, we may believe that in some morbid eases the liquid element of the fundamental portion of the villi acquires more density and increases in volume at the expense of the normal cellular ele- ment. The reason why I separate this morbid form from the fibrous transformation, notwithstanding the resem- blance in the physical characteristics of the two changes, is based upon the view I hold and which I demonstrated relative to the process of the fibrous 1 Gundziige der Pathologischen Anatomie, Wien, 1854, p. 202. FIBROMA OF THE VILLI. 343 transformation of the mucous tissue and the cells of the decidua serotina. The basic substance of the tendons is, as I believe, a product elaborated by the connective tissue cells, which are called corpuscles of the tendinous tissue. Now, in the commencement of the fibrous transforma- tion of the parenchyma of the villi, the normal cells of the mucous tissue are changed at first, little by little, into fusiform cells, then into corpuscles of the con- nective tissue, when the transformation is complete. The liquid matter changes into a transparent sub- stance. In the case of hyalin transformation the cellu- lar elements are rare and they retain the rounded form of the cells of the mucous tissue, while the other part acquires the characteristics of the elaborated fibrous substance; and yet there is not formed the elabora- . tive element, namely, the connective tissue cell. This hypothesis will be better understood when the doctrines upon the histology of the tendons shall be determined. I notice at present that in the various phases of fibrous transformation of the mucous tissue of the villi of the placenta we observe all the phe- nomena of tendinous tissue either in process of forma- tion, completely developed, or even old. The mucous tissue, previous to being transformed into fibrous tissue, undergoes in its cellular elements all the metamor- phoses which produce, successively, the characteristics peculiar to the cells of the fibrous connective tissue. In placenta, aborted at different periods of devel- opment, we find the fibrous transformation sometimes circumscribed at the trunks of the villi of the cotyle- dons, sometimes extended to all the placental villi, in a word, sometimes partial, sometimes general. The 344 FIBROMA OF THE VILLI. partial is frequently secondary and often complicated with hypertrophy of the villi included in the old clots. When the disease is primitive, it is never as cir- cumscribed as in the above case. In some circum- stances, without the microscope, we think the placenta healthy, and in others more marked, the thinness, hardness, and discoloration of the organ lead us im- mediately to recognize its fibrous degeneration. In less severe cases we sometimes find villi which assist the observation, being greatly wrinkled in their ex- ternal membrane, namely, the glandular organ. In some cases where the disease is less marked, villi have been observed upon which the external membrane, that is the glandular maternal portion, is deeply in- folded or wrinkled. This observation has been made by recent writers upon diseases of the placenta. How- ever, I believe that such an appearance, instead of consisting in a change of the external membrane of the villi, is more truly the result of a contraction of their parenchyma transformed into fibrous tissue, and that the phenomenon is produced as it were acciden- tally, in making the preparation for examination. It is a demonstration rather of the existence of an ex- ternal membrane of the villi or glandular organ. The obliteration of the vessels of the villi is almost a necessary result of the fibrous transformation of their parenchyma, for, in the greater number of cases, the two lesions are found united. I emphasize result, because, in some cases, even the trace of the vessels disappears from the midst of the villi, and in other ‘cases, where the process of the fibrous transformation is very active, we find some vessels not obliterated in FIBROMA OF THE VILLI. 345 the midst of a much larger number which have be- come occluded. The fibrous transformation of the parenchyma of the villi may exist alone or may be complicated with that of the glandular organ. Then, there is formed large fibrous cords, constituted by the fusion of several villi by means of their external walls, that 1s, the glandu- lar organ having become also itself fibrous. Finally, the fibrous transformation of the paren- chyma of the villi may take place at the same time as that of the cells of the serotina, before they have formed the glandular organ, constituting then fibrous spots of irregular shape, more or less extended upon some parts of the diseased placenta. The placenta which furnished me the most inter- esting phenomena of fibrous transformation of these various constituent elements belonged to a foetus which aborted between the fourth and fifth months of pregnancy. It was small and badly nourished. The placenta was from twelve to thirteen centimetres in diameter, and four to five in thickness, having the appearance of an atrophied membranous placenta. The chorion of the central portion could be easily separated ; it was thicker than normal, and fixed to the placenta by numerous whitish filaments or fibrous villi. Several veins and arteries of the foetal surface were obliterated by hyperplasia of their internal epi- thelial layer, as I have described occurring in certain cases of cutaneous tumors. Cut transversely, this pla- centa showed instead of the usual spongy condition a compact and uniform texture of darkish gray color. In the central and peripheral portions we observed the trace of the vessels which were obliterated in the internal part. pr E 346 FIBROMA OF THE VILLI. The complete absence of the villi in certain places. near the internal surface, where the lacune are ar- rested in their development, and the presence of fibrous villi amid the cells of the serotina in process of transformation, demonstrate clearly that the patho- logical process of the serotina and villi had taken place at an advanced stage of pregnancy, without prevent- ing the development of the placenta. Finally, the disease had attacked the borders of the central portion, completely developed, while in other — sections, especially peripheral, it had arrested the de- velopment of the constituent parts. In the greater part of its periphery, the villi of the foetal placenta were not developed, and were not, therefore, sur- rounded by the cells of the serotina, although these came in contact with the chorion, and were closely united with it; and in the midst of the villi was indi- cated the process by which was established the vas- cularization of the placenta, and the formation of the lacune. In other places the villi were developed and surrounded by the cells of the serotina, which were rapidly being changed into fibrous tissue. In the same placenta, I observed simple fibrous transforma- tion of the cells of the serotina and the same trans- formation associated with that of the parenchyma of the villi, which arrested its ulterior development ; È while in its central portion, where the normal devel- opment had already taken place, I observed the | fibrous transformation of the glandular organ and of i the villi. The trace of the obliterated vessels of the | villi demonstrate that the disease had attacked them in an advanced stage of pregnancy, and the bloody clots of the lacune confirm the fact. Tola iaia ii FIBROMA OF THE VILLI. BAT Now, in the description of a peripheral portion of this same placenta, we shall be able better to follow the histo-pathological process which changed the cells of the serotina into fibrous tissue. Moreover, we can show, by means of the traces that remain, that this morbid process, attacking the different parts of the organ, arrested its development in these places at an early period of pregnancy. In reference to the formative process of the human placenta, I have stated elsewhere that the villi of the chorion, during the first part of its formation, are completely surrounded by the cells of the serotina, and that they are at first developed more especially upon the side of the foetal surface. On the contrary, the vascularization, or placental lacuna, are formed primarily upon the opposite side, namely, on the ute- rine surface. The cells of the serotina in their normal condition are found crowded together without any regularity, and attain to a regular disposition only when, becom- ing fusiform, they envelop the villi. We observe that all the villi are imbedded in and form a net-work amid the cells of the serotina. The first change they pass through in forming the glandular organ is to be- come fusiform. When, on the contrary, they assume directly the characteristics of fibrous tissue, they re- tain their round form and their normal size diminishes. Their external membrane refracts more quickly the light, so that their outline seems clearer and more definite than in the normal condition. In their con- tents we recognize no longer as before numerous granulations, and the quite large nuclei are colored quickly by carmine. The exudation of the hyalin or 348 FIBROMA OF THE VILLI. tendinous substances, through the cellular walls, fol- lows this early period of transformation. Then takes place the disaggregation of the cellular series, which increases in direct proportion to the substance se- creted, and losing the round form, the cells take that of corpuscles of connective tissue with numerous ap- pendages in direct communication with each other. The size of the nucleus diminishes in proportion to the elaboration of the tendinous element, and the cor- puscles themselves, at the complete development of the fibrous transformation, are almost atrophied, and, as in the formed tendinous tissue, they are seen with difficulty. I do not wish to insist further upon the histological value which this observation may have in the ques- tion of the structure of the tendinous tissue, and upon the importance of said corpuscles of the connective tissue in the tendons. The fibrous tissue of the chorion on the side of the foetal surface adheres closely to the most superficial layers of the already transformed serotina. About the villi and in the cells which have under- gone the first changes for forming the glandular or- gan, the direct metamorphosis into fibrous tissue has really taken place. The lumen of the vessels of the villi still remains in a few, but is obliterated in the greater number. The fibrous tissue of the serotina is intimately blended with the new fibrous tissue of the villi. A large piece of fibrous tissue, traversed by obliterated vessels, rep- resents the fusion of several agglomerated villi by means of the cells of the serotina being transformed into fibrous tissue. Where the cells are less changed, è eo FIBROMA OF THE VILLI. 349 we perceive quite large round openings, which repre- sent dilated capillaries of the maternal placenta, ar- rested in the dilatation necessary for the formation of lacuna by the resistance which the cells of the sero- tina had acquired in process of fibrous transformation. The dimensions of the foetal vessels vary, especially the arterial. In some instances the canals are yet open, oftener they are entirely obliterated, but we can still have an idea of their size in the traces which re- main of them. The large vascular trunks, obliterated or not, un- questionably correspond to the trunks of the villi, the smallest, everywhere serpiginous and irregular, corre- spond to the capillaries which should have succeeded the ramifications of the villi in the midst of the cells of the serotina. The complete transformation of the cells of the ser- otina into fibrous tissue is observed more plainly and to a greater extent in some places near the periph- ery, especially upon the side of the uterine surface. Here it is seen that the formation of the lacune is farther advanced, but their development is always arrested, so that it is evident the fibrous transforma- tion of the cells had begun when the lacuna were already in process of formation. In describing the formation of the lacun®, I stated that the uterine capillary loops, which penetrate into the placenta, when it is represented simply by a cel- lular layer, form a net-work of meshes; that the ves- sels are dilated and enlarged amidst the cells, at first upon the uterine, afterwards upon the foetal surface, and that they are introduced by introflecting them- selves over the villi already clothed with the cells of 350 FIBROMA OF THE VILLI. the serotina, so as to form in the interior of each co- tyledon the so-called blood lacuna. Vertical sections of the inferior layer of the normal placenta, during the early period of vascularization, show a uniform cellular mass subdivided into numerous and vast ir- regular cavities filled with blood. In the morbid case under discussion, the transformation of the cells into fibrous tissue had partially prevented the formation of lacune ; however, we observe that which I pointed out in the normal condition, with only this difference, that the lamina which limit the lacun®, instead of being formed of the cellular elements of the serotina, were composed of the new elements of the fibrous tissue in various stages of development. I also stated, in reference to the formation of the lacunee, that this was effected in a manner analogous to the process of vascularization in the erectile tissues. in this circumstance, in fact, the arrest of develop- ment of the same lacune renders'clear the correct- ness of the analogy, by showing the appearance of a pathological erectile tissue. The arrest of develop- ment in the lacune furnishes, also, an important ana- tomical fact. It is only recently, and by special meth- ods, that anatomists have succeeded in demonstrating in the dilated vessels of normal erectile tissues the internal epithelial layer, so that we reject the former idea of lacune, and consider that the great cavities filled with blood are in reality enormously dilated capillary vessels. We therefore conclude that the villi of the foetal placenta, after having been enveloped by the cells transformed into the glandular organ, must also have their external surface covered by the walls of the di- FIBROMA OF THE VILLI. 351 lated capillary vessels which form the lacune. I must, however, add that, in the normal condition, neither the vascular wall nor the external epithelium of the villi are visible, except in some parts of the larger sinuses, as, for example, in the circular sinus of the placenta. The pathological case in question shows clearly the internal epithelium of the lacune, which covers en- tirely the cavities, arrested in its development. This demonstrates beyond doubt the origin of the lacune in the dilatation of the capillaries, but we have not yet been able to discover the extremely thin vascular mem- brane which should envelop the villi. In the central portion of this placenta these different parts had al- ready reached their complete development, when the glandular organ and the parenchyma of the villi were attacked with fibrous transformation. ‘The phases which the glandular organ passes through, in chang- ing into fibrous tissue, have not yet been studied as minutely as in the preceding case. The completely developed fibroma gives us to believe that the changes go on even more simply. The corpuscles of the connective tissue of the exter- nal membrane of the glandular organ are in their nor- mal state extremely minute, very transparent, and very difficult to distinguish ; now they are increased in volume and in number, and show the intimate structure of the wall which seemed amorphous. I have described, as an instance, simple fibroma of the external wall of the glandular organ, preserving in its interior an atrophied but not continuous epithelium. In reality the internal epithelium had completely disappeared and the fibrous tissue of the old glandular 352 FIBROMA OF THE VILLI. organ was lost in the fibrous tissue of the parenchyma ofthe villi ; in some places the external walls of some villi were interblended and formed numerous and large cords; these cords always allow the fibrous tissue of the villi to be distinguished from that of the glandu- lar organ on account of the different direction of the corpuscles. Vertical sections of the middle portion of this pla- centa, colored: with carmine, made most instructive and beautiful preparations. The lacune, obliter- ated by the coagulated blood, surround very transpar- ent fibrous cords, various in form and size, of which the fibrous corpuscles, deeply colored red, present different directions. The simple cords are formed by a single villus, a few show yet in their central wall a deeply granulated substance, which marks the place of the obliterated vessels; the circular arrangement of the fibrous, fusiform corpuscles, on the exterior of each villus, indicates that the glandular organ has be- come fibrous; the internal corpuscles represent the ~ fibrous cells of the old parenchyma of the villi The same phenomena is reproduced when several villi, crowded together, constitute cords of different form and volume. In reality, the fusion of the fibrous tissue of the villi with that of the glandular organ is complete, if there remains no trace of the epithelium which sepa- rates them. ) Finally, in reviewing the primitive normal change of the cells of the serotina, in process of development, of the glandular organ, we perceive that the pathologi-- cal process reduces the parts of the developed gland- ular organ to the primitive development. CHAPTER VIII. MELANOSIS OF THE PLACENTA. MELANOsIS of the placenta is a disease not recognized by pathologists. However, Dr. Beluzzi of Bologna furnished me a specimen for examination. _ The placenta belonged to a foetus of scarcely two months, the abortion was followed with considerable hemorrhage. He sent me the parts of the ovum which he could secure from among the blood clots; the envelopes were torn in several places, and there was no trace of the foetus. The external appearance of the pieces was of a thick, reddish-gray colored membrane; the color was uniform ; and thickness variable, from three to six mil- limetres, the thicker portions showed the so-called de- cidua serotina, that is, the part where the cellular proliferation commences which must constitute the maternal placenta. Vertical sections of these thick portions showed even to the naked eye a blackish line towards both surfaces. The microscopic examination demonstrated the tex- ture of the placenta: the villi upon one side; upon the other the commencing lacuna designating the foe- tal from the maternal surface. About the foetal sur- face, some villi were cut transversely, larger than ordinarily and attacked with melanosis in different stages. 28 + 354 MELANOSIS OF THE PLACENTA. The villi were in the midst ofthe cells, and the cells, which were in contact with them, had already become fusiform and completely enveloped them, forming a sort of ring about each of them. This is the first stage in the normal development of the cells of the serotina, which forms the glandular organ. In some of the villi numerous mucous cells were observed which constitute the parenchyma, but neither in the healthy villi nor in those containing pigmented gran- ules did, we find any trace of the epithelium which covers them in their early stage of development. During the early period of the development of the placenta, I have always observed that the parenchyma of the villi was wholly formed from cells as in the present case; and thus I am led to believe that this is their primitive structure. The disease, which I have called cellular hyperplasia and hypertrophy of the villi of the completely formed placenta is always only a return of the mucous tissue to its early phase of de- velopment. In the case under consideration, all the cells of the serotina had a greater transparency than normal, the nuclei and granular contents not being well defined. This led me to believe that they were attacked with an early degree of fatty degeneration. About the maternal surface portions of the small utero-placental vessels were wholly covered with granules of black pigment. | In the middle portions, the lacuna were in process of formation, and the cells which limit them were equally pigmented with like granules. Similar pig- ment granules were disseminated amid the cells of the serotina with only this distinction, that the larger ap- MELANOSIS OF THE PLACENTA. III peared rather to be interspersed than continuous. I think they represent cells of the serotina atrophied by melanosis. The lesion of this placenta is very interesting from the general anatomical and pathological stand-point. It shows, indisputably, deposits of pigment in the villi, where there has not yet been a drop of liquid blood, because they have not yet attained the period of vas- cularization. It would seem to follow that the most exact pathological deductions upon pigmentation and melanotic deposits may be erroneous. But consider- ing, very carefully, this phenomenon, the doctrine which makes the deposits of pigment depend upon hematoidin from the coloring matter of the blood! is further established and demonstrates clearly, I believe, how the nutrition of the human foetus takes place during the early months of pregnancy. Heschl? taught that the deposits of pigment could not take place as the result of stasis and hemorrhage, but only when the hematin abandons spontaneously the globules of the blood and becomes attached to the vascular walls. Now the pigmented utero-placental vessels are proof of it, and these are not the only vascular portions that I have seen diseased. I have gathered numerous and still more marked examples. That which calls for especial attention is the consider- able deposit of pigment granules which are formed about the utero-placental vessels, or infiltrated into the cells which limit the lacune, and reappear in equal if not a larger number in the interior of the foetal villi. 1 Non é luogo qui di parlare dei pigmenti derivanti da materali color- anti della bile. 2 Vedi Uhle e Wagner Patologia Generale, p. 304. 356 MELANOSIS OF THE PLACENTA. The interpretation of this fact seems clear to me. The materials of the maternal blood, which are destined to nourish the foetus, go out from the utero-placental vessels and are absorbed by the villi, after having been elaborated by the serotinal cells. In passing through the serotinal cells they leave there traces of hematoi- din which they contain in solution, then they are trans- ported and accumulate in the villi, where necessarily we find a greater number of melanotic granules. In conclusion, either I am greatly deceived, or this interesting pathological lesion of the placenta throws much light upon an obscure point in physiology: the nutrition of the human foetus, its early period of intra- uterine development. CHAPTER IX. SYPHILITIC LESIONS OF THE PLACENTA. Vircnow is the only author who has published any observations upon syphilitic lesions of the placenta; they, however, have been so limited that this illus- trious pathologist has not yet clearly formulated his opinions in regard to them. Before him, Lebert! had met several times placenta attacked with yellow granulations, having the same structure as tubercles, but to which he ascribed no especial importance. Mackenzie * observed in some foetal placenta a fibrous layer of fatty appearance. These facts are cited by Virchow* as incomplete observations. We must, according to his view, distinguish at first in the envelopes of the ovum the maternal and the foetal portion; then admit two forms of venereal endome- tritis, the placental and the decidual, according as it affects the decidua which takes part in the formation of the placenta, or that which surrounds simply the ovum. In accordance with this view Virchow grants, as acknowledged, that the decidua is not an exuda- tion, but is the superficial layer of the uterine mucous tissue modified by hyperplastic proliferation. I can 1 Compté rendu de la Société de Biologie. 1852. 2 Traité d’ Anat. Path. t. i. p. 242. 8 Canstantt’s Jahresbuch, 1854, p. 365. * Pathologie des Tumeurs, t. ii. p. 470. 5358 SYPHILITIC-LESIONS OF RHE PLACENTA here only refer to this subject, but it gives me much pleasure to find that the demonstrations which I have given upon the genesis of the decidua in the chapters upon the formative process of the placenta are con- firmed by so illustrious an author. Concerning endometritis, Virchow maintains that the simple and diffuse form produces thickening and fibrous indurations which may cause atrophy of the villi. The circumscribed form gives place to prolifer- ations which show sometimes the distinct character- istics of papules and condylomata. The first case observed by Virchow of this last kind was from an abortion at the third month of pregnancy, a primapara attacked with syphilitic ulceration of the pharynx during gestation. The principal changes were shown upon the decidua vera. It was thicker and covered upon the uterine side with growths almost polypoid, composed of very vascular, proliferating mucous tissue with no trace of little cells or fatty degeneration. Virchow states that if we cannot consider such a change as a gummy product we may find the greatest analogy with mu- cous papule or flat condylomata. He would not have doubted their syphilitic nature had not Strassmann! observed, afterward, the same lesion in a case where the mother had not the least symptom of venereal . disease. The question can be determined only by further observations. | Dr. E. Fabbri furnished me with the opportunity of examining a portion of the envelope of an ovum of about two months. The abortion was followed by severe hemorrhage. The piece examined had the ap- 1 Verhandl. der Berliner Geburts, Gesselsch. 1863. SYPHILITIC LESIONS OF THE PLACENTA. 359 pearance of a decidua showing the thickening which it has at such a period in the place where the placenta is about to be developed. Seven rounded excres- cences of various sizes, from that of a grain of wheat to that of a cherry, were suspended from the internal surface of the uterine cavity. A few somewhat larger were detached ; their surface was smooth, but some had a yellowish white color, others more or less deep red color. Microscopically, these excrescences seemed to be formed of a complicated net-work of vessels sur- rounded with young connective tissue. In vertical sections, we observed that the whitish color was su- perficial and formed, so to speak, an enveloping layer, a red and compact substance constituted the mass and gave a reddish color to those wanting in cortical substance. This diversity of color depended upon the vascularization in the red portions, the vessels were permeable and the blood circulated there freely; in the discolored peripheral portions, the vessels were completely obliterated, because of the proliferation of the internal vascular epithelium. I have mentioned under other circumstances this method of obliteration. I believe we must consider the pathological productions as true angioma, depend- ing upon an abnormal vascularization of the decidua vera or decidua serotina. Finally, if the process of vascularization sometimes produces irregularity of de- velopment in the decidua, it is certain that the most favorable conditions are oftener found for causing it in the serotina where vascularization commences with more activity. Microscopical examination demon- strated that the utero-placental vessels which pene- trated into the serotina, instead of dilating normally 860 SYPHILITIC LESIONS OF THE PLACENTA. for forming the lacune, increased and developed in the midst of cells, which, during the early period of pregnancy, are the same in the decidua serotina and decidua vera. The vessels preserved their type, but the decidual cells were transformed around them into fibrous con- nective tissue, and it is thus that the new pathological production takes place which gives, as a result, a vas- cular obliteration commencing on the periphery of the tumors. There is no reason to deny that syphilis may be, as Virchow maintains, the cause of such a change, but the case of Strassmann and that which I have just described, prove clearly that it may also be independ- ent of it. We may then have syphilitic and non- syphilitic angiomata of the placenta, or of the deci- dua; but it is certain that the angioma of the serotina, which is formed during the first months of gestation, must always cause abortion. Placental endometritis has been observed by Vir- chow only once. This was a case of abortion during the last months of pregnancy. The placenta, well developed, was covered upon the uterine side with a compact and thickened mass of the decidua, from whence arose several tumors of conical form, which penetrated into the cotyledons. Hach tumor was com- posed of a cortical or whitish fibrous capsular sub- stance and a central soft red substance with yellowish points. In some places, where the cortical layer was thicker, various yellowish cheesy spots were observed. The microscope demonstrated a dense connective tis- sue of large cells, with considerable masses of yellow cells, which had partially undergone fatty degenera- tion. The villi of the chorion were closely envel- SYPHILITIC LESIONS OF THE PLACENTA. 361 oped with this tissue by which their epithelium was supported; their structure was unchanged, only the parenchymatous tissue was shown here and there more compact and more abundant. I can give no observation, especially my own, which compares with this description. I will simply add, that many of the so-called hollow moles of ancient authors find prob- ably their place, as I believe, among the angiomata ‘ which I have just described. CHAPTER X. THROMBI, APOPLEXY, AND HAEMORRHAGE. Tue localized collections of coagulated blood in the placenta, or the more or less extended bloody extrav- asations, constitute a morbid form of disease, which is often found in abortions of advanced pregnancy or even at full term. Notwithstanding this frequency of placental disease, its causes are not as yet definitely understood. The disagreements of authors upon this subject are numerous. According to a few, apoplexy of the placenta is a true hemorrhage, consequent always upon laceration of the vessels. Coste, considering the lacuna as lakes of blood, in which the villi swim, declared that true hemorrhages are impossible. Bustamante, Virchow, and Bailly have maintained that placental coagula are only more or less large blood-clots, which they call thrombi of the sinus. Others, finally, believe that apoplexy is always the result of a lesion of the villi, usually fibro- fatty degeneration, which I have clearly demonstrated to be an hyperplasia and hypertrophy of the cells of the mucous tissue of the villi. My own observations convince me that if, in many cases, there are simple thrombi of the sinus, in other cases there is a real haem- orrhage. Before reporting the result of my study, I will review the contrary opinions which have been THROMBI, APOPLEXY, AND HEMORRHAGE. 363 advanced. Jacquemier published in 1339 a special work upon the bloody extravasations of the placenta, which was judged most complete. He held, as a dem- onstrated principle, that at least pathological lesions of the utero-placental arteries exist, and that hamor- rhages of the placenta are always the result of venous lacerations in the placental or decidual tissue. He es- tablished, in this manner, two forms of placental hzem- orrhages ; one where the extravasation is sub-chorial, and one where it invades the parenchyma of the pla- centa. In the first instance, the chorion is acciden- tally detached from the amnion, and hemorrhage takes place between the two membranes. Gendrin had found some facts of this kind, and, moreover, had seen a bloody infiltration in the mu- cous tissue surrounding the vessels of the unlacerated cord. | 3 ) In the second instance, the bloody extravasations are of three distinct kinds: 1. The extravasated blood hollows out an irregular cavity with prolongations in various directions, which sometimes causes even the separation of the chorion from the placenta, and the laceration of the coronal sinus which is always found in communication with the hemorrhagic centre. 2. The blood seems to be infiltrated into one or several lobes of the placenta, without any real apoplectic cen- tre. 3. The blood is shown in irregular and circum- scribed centres, of which the number varies from two to twenty, with different capacities, according to the successive transformations produced by coagulation. Joulin wrote in 1867 that the hxemorrhagic centres might have their origin either in the utero-placental mucosa, or in the substance itself of the placenta. 964 THROMBI, APOPLEXY, AND HEMORRHAGE. The bloody extravasations are, as he believes, the re- sult of fusion of the vessels, and the partial destruc- — tion of their primitive walls. The quantity of the effused blood and the pressure which it exercises upon the surrounding portions may occasion disturb- ance to a certain extent, and may cause the blood to penetrate into the neighboring cotyledons. The hemorrhages which occur upon the side of the uterine mucous membrane are proved by the clots which we find sometimes in the midst of the uterine decidua. I had an example of this in the envelopes of an embryo of about two and a half months. Not only were the hemorrhagic centres visible in the thickened portion of the serotina where the villi had already penetrated, but also in that portion where there was. no trace of them. In my previous studies, I have already demon- strated that, during the early months of pregnancy, the uterine decidua is traversed by reticulated capil- lary vessels, in the midst of the new-formed cells which constitute it, and that these cells are identical with those of the serotina. During pregnancy, the cells of the portion of the serotina corresponding to the place where the ovum is arrested proliferate, and are changed so as to form, with the chorial villi, the placenta. On the other hand, the cells of the uterine ‘decidua and the thin, vascular network which traverse them undergo a retrogressive change. Soon after the fifth month we no longer find the vessels, and towards the end of pregnancy the cells lose their form and give to the decidua the appearance of an exuda- tion. This only renders probable the fact that during THROMBI, APOPLEXY, AND HEMORRHAGE. 365 the early months of gestation the vessels of the uter- ine decidua may be broken, and produce hemorrhage between it and the chorion. But the observations of Jacquemier, and those more recent of Blot? and my own demonstrate it beyond question. In my own especial case I am not quite certain whether the various hemorrhages of the decidua were the result of an abnormal vascularization, that is from a tendency to form lacun® as in the serotina, or from a lesion of the walls of the capillary vessels, which rendered them incapable of resisting the pressure of the blood, or from a want of resistance upon the part of the cellular elements of the decidua. In the case under discussion, the cells of the serotina do not show clearly the fatty degeneration which is, when occur- ring in the cells of the serotina, the most common and potent cause of internal hemorrhage of the pla- centa in its various stages of development. In an- other case the fatty degeneration of the cells of the decidua vera was evident, but I could not determine if the haemorrhage was limited to this cause. Dubois and Desormeaux$ and also Simpson, ob- served the congestional condition in apoplexy of the placenta. The congestion may consist in an extraor- dinary accumulation of blood in the sinuses, or, as they stated, in the spongy mass of the placenta; the extravasation or apoplexy may be only a secondary phenomenon of this morbid state. It is deduced from the above that it is generally believed that the hamorrhage proceeds from the lac- 1 Archives de Médecin. 1839. 2 Société de Biologie. 1850. 8 Dictionnaire des Scienc. Med. 1840. a 366 THROMBI, APOPLEXY, AND HEMORRHAGE. eration of the maternal vessels. Millet,’ however, has maintained later that the apoplectic disturbances in the centres of the cotyledons are the result of the rupture of the vessels of the umbilical cord, and not from the maternal vessels. According to Charpen- tier, dilatations almost aneurismal have been found in the vessels of the cord near their placental insertion, and this supports the theory of Millet. It is certainly possible that the vessels of the cord or of the villi may be torn. I have already cited one case in which the dilatation of the villi was considerable ; if I am not mistaken in attributing this dilatation to a mechani- cal obstruction in the circulation, their rupture be- comes much more probable. But we cannot easily understand why the vessels of the villi, opening and pouring out the blood into the large placental sinuses, should form a clot rather than a mingling of the ef- fused and the maternal blood. We must add that the quantity of effused blood generally surpasses the amount of foetal blood, so that it is impossible that it can be furnished by it alone. Ido not deny the ob- servations of the ruptured umbilical vessels which Charpentier has mentioned, but these and those of the dilated vessels of the villi which I have noticed indi- cate only the possibility of a fact which will in reality occur only as a rare exception. In these later years, Dalton, Farre, Robin, and Coste, in studying the special manner of vascularization of the maternal portion of the placenta, have established that the foetal villi swim in the blood lacune corre- sponding to the cotyledons, and that the large internal areas are filled with maternal blood constantly in mo- 2 Thèse, 1861. 2 Maladies du Placenta, Paris, 1869, p. 9. THROMBI, APOPLEXY, AND HEMORRHAGE. 367 tion. In consequence of this new anatomical knowl- edge of the placenta, some pathologists have supposed that the above theories concerning placental heemor- rhage cannot be true. Bustamante,’ accepting as fact that the villi are directly bathed in the maternal blood, states that the placenta is found in a condition of constant hem- orrhage. He adds that the maternal blood, having entered the sinuses, undergoes forcibly, on account of the size and irregularity of the lacune, a slackening in its current, and that it is to this phenomena that the name of apoplexy or placental haemorrhage has been given. Finally, under the influence of this dim- inution of current and the condition of pregnancy, which modifies the temperature of the blood and pre- disposes it to coagulation, the bloody fluid becomes clotted and imprisons the villi, and as the coagulation is rapid or gradual, we have compact or stratified clots. He thought these diseases should take the name, thrombi of the placenta. One easy objection to be made to the theory of Bustamante is this: the anatomical and physiological conditions which, accord- ing to him, favor thrombosis, always exist without the thrombi being constant. Thus there must be some pathological element to produce them. Virchow,? while admitting the fact of thrombosis, has not be- stowed much attention upon the main point in ques- tion. He is content to affirm that the placental he- matoma are generally the result of partial thrombi. He does not deny that we meet with true hamor- rhagic clots, especially on the foetal surface of the placenta, but he believes they constitute a thrombus 1 Etudes sur la'Placenta. 1848. 2 Pathologie des Tumeurs. È per 868 THROMBI, APOPLEXY, AND HAIMORRHAGE. of the placental sinus. Bailly! examined the question more thoroughly, and after having communicated his views to Charpentier, he published and developed them himself. According to his views, the possibility of a placen- tal hemorrhage is not admissible, now that the struc- ture and the vascularization of the maternal portion of the placenta are known. Since the demonstration of the blood lacune of the cotyledons, in which the blood is always in motion, the necessary conditions for the formation of apopletic centres, and still more those of hemorrhagic centres are wanting, for the villi are always found immersed in the blood, in a state of continuous and physiological hemorrhage. That which might accidentally penetrate there, by ming- ling with the blood which traverses constantly the great cotyledonary lacune, would be carried along with this through the outlets of the blood lake. The question then would really be that of a new haemor- rhage in the midst of a permanent hemorrhage. Thus they are mingled together, producing no other results than a momentary increase of the fluid in circulation, and a tension of the blood against the walls of the lacunz. As to this, it is certain that so long as the placenta retains its normal anatomical constitution, and the inter-utero-placental blood-currents continue to traverse freely the spongy mass of the villi, the formation of apopletic clots is impossible. The opposite occurs when a fibro-fatty change of chronic character, gluing together the villi, and di- minishing or suppressing in these the maternal and the foetal circulation, has transformed the spongy and vas- 1 Gazette des Hépitaux. Agosio. 1870. THROMBI, APOPLEXY, AND HEMORRHAGE. 369 cular structure of the placenta into more compact and less or not all vascular tissue. In placenta thus changed, we understand easily the formation of blood clots, produced by the slackening of the course of the blood, which is the condition most favorable for coag- ulation. Bailly concludes* that the fibro-fatty degeneration, formerly known under the name of cancerous and tu- berculous induration, depends in no respect upon a preéxisting apoplexy of the organ, and that apoplexy is not the result, but is a preéxisting and necessary condition of the change. In these later years the re- lation of fibro-fatty degeneration of the villi with hem- orrhage of the placenta has been.the subject of long and obscure discussions. Dubois and others have regarded the placental plates, called scirrhous, and the absence of all vascu- larization in the hardened portions, as a direct result of an effusion of blood. Itis the blood that coagulates about the villi, stops the circulation, and occasions atrophy. The yellowish color and the lardaceous consistency depend upon the slow transformation of the blood, and especially of the fibrine. These are the precise changes I have described al- ready, under the denomination of hyperplasia and hy- pertrophy of the cellular elements of the mucous tissue of the villi. Robin had previously excluded, in a categorical manner, the bloody suffusion, by at- tributing the disease to the fatty destruction of the placental tissue, and more especially to an atrophied obliteration of the capillaries of the villi. Hence came the modern name fibro-fatty degeneration, con- 1 Gazette des Hòpitaux, 1870, pp. 366-379. 24 370 THROMBI, APOPLEXY, AND HEMORRHAGE. founding the fibrous change of the villi with the cellular hypertrophy and the complienolg, which fol. low from it. The observations of Robin have served to support a truth which contradicts the doctrine generally ad- mitted. They prove that the so-called fibro-fatty change is not the result of hemorrhage, and that it is caused independently of this phenomena. Bailly declared that we often find placenta affected with fibro-fatty degeneration without a trace of coagulated blood. He gee that such a change is an in- dispensable condition for the formation of apoplectic centres. His opinion was founded upon this, that he had never noticed a single. apoplectic centre which might not coincide with a fibro-fatty degeneration, or a kindred change of the placenta, and be located in the most diseased parts. The value of this argument is only apparent. It is certain that the villi comprised in a clot are always changed in consequence of the abnormal anatomical conditions in which they are found; in such instances, I have constantly verified the fibrous transformation and the atrophy of the vili. Admitting then for the moment, with the privilege of proving them real, that the thrombus and hemorrhage of the placenta are pos- sible, for a reason entirely different from that held by Bailly, it would follow, that the lesion of the villi, in- stead of being a necessary and preéxisting condition for developing blood clots, is, upon the contrary, an in- evitable consequence of the coagulation of the blood in connection with the solidity which thereby ensues. Bailly relates, in his last work, that having set forth his views in the thesis of Charpentier, Professor De- THROMBI, APOPLEXY, AND HEMORRHAGE. 371 paul presented to the Surgical Society a placenta, which proved that the apoplectic clots may exist inde- pendent of a fibro-fatty or any other degeneration which has preceded and predisposed hemorrhagic le- sion. Out of respect to his teacher, he limited him- self, in simply mentioning the precise fact; but we must admit that his peculiar theory was not entirely true or was too exclusive, though it may be regarded in a greater number of cases as true. * Hence, we must acknowledge, that there are very numerous doubts upon the subject of so severe and common a disease. The theory of Jacquemier is re- futed by the anatomical light we have acquired upon lacunary and maternal circulation in the placenta; that of Bustamante is too exclusive, since it is unde- niable that we find bloody coagulations and thrombi, as well as bloody extravasations or real hemorrhages, in lacerations of any part of the organ. The pathologi- cal condition of Bailly may explain, in some instances, the clots, but it does not account for the haemorrhages. Moreover, we have demonstrated that the two lesions may be independent of each other, and that, oftener, there is fatty degeneration without clots and without heemorrhage. I agree with the illustrious Depaul that we can have clots and placental hemorrhage without change of the villi. I have myself had occasion to verify it, but I cannot admit that in the example which he furnished some other lesion may not have existed which pre- ceded and caused the hemorrhage. The previous le- sion, which becomes the chief cause of clots and haem- orrhage, is the fatty degeneration of the cells of the decidua serotina. 372 THROMBI, APOPLEXY, AND HEMORRHAGE. I find no record of such observation, but from my previous studies upon the structure and method of formation of the placenta of woman, I am happy to be able to explain by this change the etiology of the va- rious hemorrhagic forms of the placenta which take place during pregnancy. For this purpose, it is wise to review, in a few words, the manner of vascularization of the maternal placenta, in order that we may see the anatomical cause of the frequency of placental hemorrhages dur- ing the early months of gestation. In the place where the ovum comes in contact with the decidua, the cells of the new formation proliferate more abundantly and form a thicker layer than elsewhere. During the first months of pregnancy, all the constituent elements of the placenta are found in this cellular layer, which has been named decidua serotina. The placenta, as many obstetricians believe, is developed only towards the third month; however this may be, the formative process commences in this bed of the decidua sero- tina, and, in vertical sections, we see here the villi imbedded in the portion toward the foetal surface, while the vascularization of the maternal placenta commences in the part near the uterine surface. In the case above referred to, of placental pigmen- tation, the change from the normal condition was only in the presence of granules of melanotic pigment, in the foetal, as well as the maternal portion, and in the fatty degeneration of the nuclei of the decidua sero- tina. The villi represented the foetal portion and the serotinal cells the maternal, in which the lacuna were + in the initiative process of formation. | During the early months of pregnancy, the cells of THROMBI, APOPLEXY, AND HEMORRHAGE. 373 the uterine decidua and those of the decidua serotina are traversed with a network, in large meshes, of ca- pillary vessels, which commence immediately to dilate and change, so as to form the lacune of the serotina, while they gradually disappear from the uterine de- cidua and this latter assumes the appearance of a sim- ple exudation. In the decidua serotina, the vascular dilatation takes © place very rapidly, and the formation of the lacuna is already far advanced in the uterine portion while as yet there is no trace of them in the foetal portion, where the villi are found. Different morbid causes may arrest the development of the lacune. The villi descending even to the uterine surface of the pla- centa, in the midst of the cellular partitions of the lacune, are enveloped by the glandular organ; at the same time, the lacuna extend, surround, and in- close the villi in the upper layer of the placenta and reach even to the chorion, retaining the same cellular nature which the layer of the serotina that touches the uterus maintains even to the close of pregnancy ; these partitions which extend even to the chorion serve to separate the cotyledons. Sirelius had already described these anatomical ar- rangements, and had further observed, without taking much notice of it, that the rupture of these separations caused severe hemorrhages in the interior of the pla- centa. | We know that placental hamorrhages frequently occur during the first three months of embryonic life, and that, at the third month, they take place more easily on the side of the foetal surface. Virchow, al- though favoring the view of the formation of thrombi 374 THROMBI, APOPLEXY, AND HEMORRHAGE. of the sinus, must admit that the sub-chorial blood extravasations should be considered as real heemor- rhages, because of their greater or less extension. In my numerous observations, I have always found — that the hemorrhages coexist with the fatty degener- ation of the cells of the decidua serotina, so that it appears to me easy to understand that the cells, thus transformed, support very poorly the pressure of the blood of the lacune and cause, by disintegrating, ver- itable haemorrhages. The so-called development of the lacune explains how it happens more easily in the early months of pregnancy, and why, at the third month, it occurs more frequently upon the side of the foetal surface. In short, the close relation of the pathological le-. sion of the cells of the decidua serotina with the ana- tomical conditions of placental development may be the cause of haemorrhage, especially when the lacu- nary circulation is about to be completed. I have re- cently examined a human ovum of two months which had the appearance of a large blood clot. The fatty degeneration was very considerable in the cells of the serotina, in the midst of which I observed a few im- perfectly formed villi. The cells of the uterine de- cidua were also fatty, being suffused and comprised in the clot. Does the blood which infiltrates, so to speak, the uterine decidua proceed from the ruptured lacune of the decidua serotina, or, on the other hand, both from those and the little vascular network of the decidua itself? Iam unable to solve the question. In every in- stance, the histological and clinical observation agree in demonstrating that the premature fatty degenera- THROMBI, APOPLEXY, AND HEMORRHAGE. 375 tion of the cells of the decidua serotina and of the uterine decidua causes dangerous and extraordinary hemorrhages during the first months of pregnancy. When the same change occurs later, when the vascu- larization of the foetal portion of the placenta is accom- plished, that is about the third month, the hemorrhage occurs more easily in this portion of the organ, so that we clearly perceive the effused blood under the chorion. When the fatty degeneration attacks the cells of the decidua serotina, at a period when the placenta is complete, it can extend to the layer of cells, which retain their form even to the end, only upon the uterine surface or in the inter-cotyledonary cavities. Hemorrhages of the uterine surface are conse- quently much more common ; those of the interior of the placenta are less frequent and occur in several places. The rupture of the layers of the serotina allows the blood to go from one cotyledon to another, and pro- duces necessarily a slackening in the circulation of the maternal blood in the lacuna. Then takes place the condition which Bustamante has in vain sought in the normal state, in order to find the cause of the blood clots which he attributed to a thrombus. We understand easily how the presence of a clot in the in- terior of the placenta, if abortion has not taken place, presents an obstacle to the lacunary circulation and a favorable circumstance for the formation of several circumscribed thrombi. Finally, we are also persuaded without any dif_i- culty to consider that the fatty degeneration, having extended into the cells of the decidua serotina, is at 376 THROMBI, APOPLEXY, AND HAMORRHAGE. all periods of pregnancy rather an occasion of severe and fatal hemorrhage than of thrombi. In pointing out the cause and the reality of placental hemorrhage, I do not exclude thrombus of the sinus, nor do I pre- tend that the blood may not coagulate in the lacuna at even a more extended point than that which has been observed. I have demonstrated it when describ- ing a form of hyperplasia and of hypertrophy of the cells of the mucous parenchyma of the villi, and in a case of fibrous transformation of the same villi. Now, it is evident that in the conditions which I have set forth the same phenomenon may be partially realized in consequence of lesions identical with portions of the villi, and produce circumscribed bloody coagulations, or, as some call them, partial thrombi of the sinuses. Fatty degeneration is very common in the cells of the decidua serotina during the early months of preg- nancy. We recognize it easily by the transparency and the brightness of the nuclei. At the commencement of the change the nuclei become more voluminous and their numerous internal opaque granulations dis- appear completely ; the outlines of the cells are less clear and distinct. In the most severe cases that I have observed, in place of the cells, I found a kind of transparent semi-fluid, strewn with oily masses of a yellowish color and various forms, which retained a certain regularity of distribution through it; so that we concluded that these masses were composed of the old nuclei of the cells of the serotina, the external wall of which we could no longer distinguish. In perfectly developed placente, and at the close of pregnancy, we find often fatty degeneration of some of the cells of the bed of the decidua serotina, which THROMBI, APOPLEXY, AND HEMORRHAGE. 377 ® is in contact with the uterus. In one instance of an old fibrous clot of this region, the size of a nut, com- prising a portion of the serotina and some fibrous villi, I observed that upon the surface of the clot the cells of the serotina had the appearance of a tissue of gray- ish color which, microscopically examined, showed no trace of its structural origin. The fatty degeneration was, perhaps, limited to a small portion of the placen- tal cells in the beginning of pregnancy, and the hem- orrhage which supervened was not sufficiently severe to disturb the course of gestation. CHAPTER XI. TRANSFORMATION OF BLOOD CLOTS AND NEOPLASIA OF THE PLACENTA. THE color of recent blood clots is always deep red ; even in cases of severe hemorrhage, determining promptly abortion, the blood is found coagulated in the interior of the placenta. This proves that the coag- ulation of the blood is rapid when there is a real heem- orrhage. When the blood coagulated in consequence of hemorrhage or thrombi remains long in the placenta, it undergoes remarkable changes. Generally we can say that the blood clots abound in white globules, that we find there amorphous or crystallized hematoidin, that gradually, if they are formed only of fibrine, as often happens, they become of a yellowish-white color. Formerly these old clots were considered as scirrhous, because of their hardness, or as tubercles, so called, from distribution in little masses, or their infiltrated character. In some instances the clots become soft- ened. When the blood globules are few and the fibrine is reduced to molecular granulations, then the fluid which results is considered, because of its appearance, as pus. The changes in the color of the clots depend on the time and method of formation. From the ef- _ fect of time the clot is condensed and becomes more firm, the discoloration commences in the periphery, except in those cases where it is formed by successive TRANSFORMATION OF BLOOD CLOTS. 379 superposition of more recent effusion. Under these circumstances the clot is hard and discolored in its centre; on the exterior, on the other hand, it. may have the characteristics of freshly coagulated blood. Stratified clots of various color and consistency have been observed in the different layers; sometimes we have found small cavities of dark fluid blood, or of yellowish substance, which Jacquemier has compared to that of meliceris, or soft adipose substance, analo- gous to steatoma. The most circumscribed clots, even, are never cystic, only in a few cases the ex- terior layer shows the appearances of one. Jacquemier has, moreover, stated that the villi in- closed in the clots were deformed and obliterated. I myself have seen them, as I have stated, atrophied by fibrous transformation. I am, therefore, disposed to believe with Bustamante, that the atrophy and oblit- eration of the vessels are the result of the compres- sion of the clots, contrary to Moreau and Bailly who regarded the lesion of the villi as primitive. Verdier,! reviewing the conditions he had observed in the clots, affirmed that they may be condensed and become per- manent, destroyed or organized. Before disappearing, the clots must go through va- rious phases; the fibrine assumes a lardaceous, yellow- ish aspect; the fibrillary appearance, at first, gives place to two kinds of granulations, the one of proteic nature, soluble in the alkalines and in acetic acid, the other of fatty nature, resisting these reactive agents. The white globules, having become fatty in the inte- rior, remain. Owing to these changes, the mass of the fibrinous clots is softened, becomes liquid, and takes the appearance of pus. 1 Thèse. Paris, 1868. sli 380 TRANSFORMATION OF BLOOD CLOTS. Brachet, in conformity with older authorities, re- garded this liquid as true pus, produced by inflamma- tion. We cannot deny that pus may not be formed in the placenta. Billroth observed the real transfor- mation of the blood into pus in thrombi. Vulpian, studying these purulent masses of the placenta, found very abundant fatty and fibrinous granulations, liquid matter, modified white cells, granules composed of fatty molecules, and an infinite number of crystals of hematoidin. The organization of the clots was, at first, denied by all pathologists, Virchow included, then demon- . strated by O. Weber in thrombi, and afterwards con- firmed by Virchow himself. I have myself described the successive transformations of the white globules in order to constitute the cicatricial tissue of the tendons. and their metamorphosis into bony corpuscles in the formation of the callus of fractured bones. We must, therefore, admit the possibility of the organization of placental clots in neoplasia; these diseases, however, are very rare, and it is not yet demonstrated whence they take their origin. Those who have observed the progressive changes of the blood clots have especially taken into consider- ation the time and kind of formative process. I have never observed the transformation either into fat or purulent masses, pus, or into neoplasia. I have, however, noticed that in apoplectic centres the diver- sity of color does not depend simply upon the time or method of change, but also upon the quality of the lacunary blood and the time employed in coagulation. In a placenta at full time I found, upon the uterine surface, amid the cells of the serotina, an old clot the TRANSFORMATION OF BLOOD CLOTS. 381 size of a small nut, exclusively formed of layers of hard, compact fibrine, of yellowish white color. The cotyledons contained several agglomerations of villi, attacked with fatty degeneration or cellular hyper- plasia of the parenchyma, inclosed in clots more or less soft and in different shades of red. About the foetal surface, in one of the morbid centres, they were agglutinated together by a soft, amorphous, yellow- ish, gray substance, with no trace of blood globules. The lesion was recent, and the pressure must have been moderate, for several villi showed their central vascularization very pronounced. The villi comprised in the really old clots always present the obliteration of the vessels and fatty degen- eration, complicated sometimes with atrophied defor- mation, when the clot is composed only of fibrine. Pathological observations have been especially directed to clots more or less circumscribed. I am not aware if any one has examined thrombi, diffused through the whole or greater portion of the lacunary sinuses, such as I have pointed out when describing cases of fibrous transformation of the parenchyma of the villi, cellular hypertrophy and hyperplasia. I found that the la- cune under these circumstances were less spacious, a fibrillated appearance of the coagulated fibrine was manifest in several of them, and in others the fibrine was reduced to a state of molecular granulation, while a few, placed in the midst of those which were entirely obliterated, allowed the maternal blood still to circu- late in them. Repeated observation has always shown that the condensation of the blood-clots of thrombi is the most frequent condition, and that cases where the clots are 382 TRANSFORMATION OF BLOOD CLOTS. transformed into purulent matter are rare. Charpen- tier in collecting these found only ten. Neoplasia of the placenta, whether they have, as a starting point, the blood-clots of the placenta or not, are, however, a very rare form of disease. Dr. Dun- yan, in 1844, described two cases of tumors of the placenta, excluding relatively from their nature mon- strosity, mole, fatty degeneration of the decidua, and cancerous change. He referred their genesis to for- mer blood extravasation. Dr. Pelzer? sent, in 1858, a placental tumor to Virchow, who gave a description of it. A certain number of smooth, round, hard swell- ings, the thickness of the hand, started out from the midst of the villous parenchyma. A closer examina- tion demonstrated that one cotyledon was much more developed than the others, and formed a heteromor- phous tumor, in a placenta otherwise normal. The increase in volume comprised the whole of the coty- ledon, for, on one side, it extended to the chorion, and, on the other, the secondary and tertiary divisions of the villi were equally affected by it. The central nod- ules, as large as a pigeon’s egg, were inserted by ped- icles into other nodules, whose volume varied from the size of a grain of millet to that of a hazel nut. The microscopical examination demonstrated that in the interior of the red nodules there were numerous and large vessels with strong walls. The mass of the tumor consisted of dense, areolar tissue containing cells with round nuclei, resembling greatly the pe- ripheral cells of the umbilical cord. Virchow states, that we must distinguish this pecul- 1 Journal de Chirurgie. ? Pathologie des Tumeurs, t. i. p. 415. Paris, 1867. TRANSFORMATION OF BLOOD CLOTS. 383 iar condition of hematomatous nodules, resulting from partial thrombi of the tissues, from the myxomatous products, designated under the denomination hyper- plastic myxoma. This description seems to me to give a correct idea of the intimate structure of the neoplasia under dis- — cussion ; if myxoma, according to the German pathol- ogist, is the epithelial production of hypertrophied villi and the vesicles of hydatid placenta which I have described, we cannot see the analogy they have with this new form which he declares is richly furnished with vessels. I must notice that the illustrious President 1 of our Institute has demonstrated the existence of vessels in the mucous tissue of the umbilical cord, called gela- tine by Wharton, contrary to the declaration of Vir- chow who denied their existence. In supporting the observations of Calori, we must admit, a priori, vascu- lar myxoma, and I have already clearly shown how far removed the opinions of Virchow are from the true re- lation to the pathogenesis of myxoma of the hyper- trophied chorial villi and from hydatid placenta. It seems to me superfluous to inquire if the case which he describes, and which he himself calls astonishing, should not be considered as an unusual development of the morbid form which I have observed in the state of formation in the placental villi, and which I have described as myxoma of the decidua serotina in order to conform to the classification of Virchow which has been adopted by science. Eberth in 1867 and Vinogradow in 1870 observed 1 Calori, Memorie dell’ Accademia delle Scienze dell’ Instituto di Bo- logna, ser. 2, t. 1. p. 208. 384 TRANSFORMATION OF BLOOD CLOTS. true myxoma of the chorion in the limited signification given to this word by Virchow. That of Vinogradow! was situated three inches from the placenta between the chorion and the amnion, large as a goose egg, pale © grayish color, soft as gelatine, and its form variable as if filled with fluid. However, separating the chorion from the amnion so as to examine better the tumor, no liquid escaped from it, and it was perceived that the neoplasm adhered to both membranes by means of delicate fibres which separated and traversed its gelatinous substance. The microscope showed that this was composed, for the most part, of homogeneous and transparent inter- cellular matter, and, in part, of granulous and filamen- tous substance, in the midst of which were found cells of different shape, star, fusiform, or irregularly pro- longed. The prolongations anastomosed with each other and formed an elegant network, in which were seen large cells having the characteristics of mucous corpuscles filled with fine granulous substance. Acetic acid ren- dered more apparent the cellular elements and the delicate fibrils, by causing the basic granulous sub- stance to disappear. The observer diagnosed a neo- plasm formed of matter identical with the gelatine of Wharton, which had its origin in the mucous tissue of the chorion. 1 Archives, etc., September, 1870. CHAPTER XII. PLACENTAL CYSTS. Very few observations have been made upon cystic degeneration of the placenta. Bustamante in 1848 described one case, Millet cited two others in 1861, and Charpentier reported two in 1869. Placental cysts have only been observed upon the foetal surface. The exterior wall is formed by the chorion. They are round, or pedicellated in form, and vary in size from a cherry-stone to a hazelnut. Millet declared that the fluid they contain is identical with the gela- tine of Wharton. Bustamante believed these cysts have an origin from hematocele, and are partly fluid and partly solid. The liquid, slightly gluey, is of a lactescent lemon color and contains blood globules. Heat and nitric acid show the presence of albumen, and in the bottom of the cystic cavity is found a yellowish-white substance, composed of coagulated fibrine. In one of the two clinical cases reported by Char- pentier, there was a small, pyriform cyst on the foetal surface of a placenta of the sixth month of pregnancy. The contents of the cyst was of a brown color, con- sistency of mucus, and showed microscopically, well- preserved blood clots and leucocytes containing gran- ules and free fat. In the second case the foetal surface showed three cysts having the characteristics de- 25 386 PLACENTAL CYSTS. scribed by Bustamante. The inferior, solid portion contained villi surrounded and glued together with reticulated granulous fibrine. Upon the uterine sur- face and in the interior of the placenta, several other apoplectic centres, or thrombi, were observed. I have had opportunity of examining only two cases of this kind. One had been preserved for a number of years in the Anatomical and Pathological Museum in a so- lution, at first of bichloride of mercury, afterwards in alcohol. Its preservation was imperfect. The whole foetal surface of the placenta was strewn with round tumors, covered with the chorion, the largest of which was the size of a cherry. A few had been opened, in which solid matter still remained, and resembled those described by Bustamante ; others showed a cer- tain solidity. On section, I found the cavity of the growth was filled with coagulated fibrine, in the midst of which rounded and agglomerated masses of granu- lous hematin could be distinguished. Because of im- perfect preservation the histological relationship of its parts could not be determined. The following ob- servations I made upon a placenta from an abortion soon after the third month, and which had remained in the uterus some time after the death of the foetus. The manifest condition of the freshness of the placenta contrasted singularly with the signs of saponification beginning in the foetus. The cord was very thin, and its vessels atrophied and obliterated. Upon the foetal surface we could plainly see three hemorrhagic cen- tres, of red color, round form, each having the size of a small pea. Others were less raised and more irreg- ular in form. Examining those which exteriorly re- sembled a cyst, I was assured that this was not real. PLACENTAL CYSTS. 387 The external wall was formed by the chorion, and covered all the bloody mass which composed half of the sphere arising from the foetal surface. ‘The other half was buried in the placental tissue, in immediate contact with the effused blood. The denomination of cyst is therefore incorrect. The portions of the placenta which constitute the basis of these tumors are villi, having undergone fibrous transformation, pressed upon by the interposition of coagulated fibrine which forms a compact and circum- scribed layer. In this layer we notice here and there deposits proceeding from the cells of the decidua sero- tina, a few of which show clearly fatty degeneration of the nuclei. Amid this mingling of portions united together by means of lamellated fibrinous clots, we perceive also in large numbers little calcareous con- cretions, various and irregular in form, scattered with- out any order. I have already observed that upon the foetal sur- face of this placenta, we noticed blood clots; not spher- ical, but almost flat in shape, which scarcely elevated the chorion. A few of these clots penetrated even to the uterine surface, forming irregular and very ex- tended haemorrhagic centres. Others, some very small, were seen in the central portions. They were formed by villi surrounded with fibrinous deposit and blood. Here, as in the hemorrhagic centres, the villi were affected with fibrous transformation. In the midst of the blood clots there were fatty particles and cal- careous concretions, similar to those which I have described above. These observations are offered in evidence that the so-called placental cysts have gen- erally traumatic origin, and are really a circum- 388 PLACENTAL CYSTS. 0 ; scribed hemorrhagic form of maternal blood. The differences demonstrated in the clots agree with the changes observed by Millet, and are filled with mate- rial analogous to the gelatine of Wharton. It is true Charpentier examined a cyst of this kind in a pla- centa, for which he offered other than hematic origin ; but this argument is not, I believe, sufficient to refer to a special transformation of the elements of the clot, the peculiar characteristics of the contained liquid. Instead of supposing that the mucous tissue may be accumulated in certain portions of the pla- centa, I prefer to leave the question unsettled, and wait until further observations shall determine its solution. — The observations of Ebert and Vinogradow, de- scribing true myxoma of the chorion, may indeed explain the above indicated differences of the cyst, but at the same time the denomination of cyst for true myxoma of the placenta is incorrect. CHAPTER XIII. CALCAREOUS CONCRETIONS OF THE PLACENTA. CaLcaREOUS concretions of the placenta have been observed from the most remote time. I shall there- fore only report the facts which science possesses upon this subject, and which my own studies have confirmed. Calcareous concretions are found gener- ally upon the uterine surface, either stellated or needle-shaped. Depaul remarked that when they are numerous and somewhat developed they give to the touch the sensation of a soapy surface. In one case which I myself examined, the little stellated de- posits were so exact and uniform that the touch gave no sensation of them. The numerous appendices of these little concretions led Lobstein and others to be- lieve they were vascular ossifications. Robin demon- strated that the calcareous matter was deposited in the mucous layer which covered the placenta, namely, in the cells of the decidua serotina. He stated, more- over, that it was not very rare to find a portion of the placenta strewn with little calcareous granulations which form by intermingling more or less large con- cretions. Upon the uterine surface, they constitute sometimes plates which Carestia has seen upon the foetal surface. Deker and Millet cited one case of this kind, in 390 CONCRETIONS OF THE PLACENTA. which they counted more than two hundred calculi, the largest of which was the size of a hazelnut. The small concretions, that I have observed in large numbers, belonged to a placenta from a seven months’ foetus which had remained in the uterus some time after the foetal death. All the villi were affected with fibrous transformation. I mentioned in the preced- ing chapter these same granulations limited to a por- tion of the placenta. We know the calcareous con- cretions in the interior of the placenta are generally found in the inter-cotyledonary spaces, which we now believe to be composed of the cells of the serotina. I have observed only one case of this kind, and that belonged to a placenta largely affected with cellular hyperplasia of the parenchyma of the villi. The con- cretion was the size of a cherry-stone, situated under the chorion amid the cells of the serotina, which sep- arated two cotyledons. In placenta, of which the villi are affected with fibrous transformation, the lit- tle concretions are not found in the interior of the villi, but upon their external wall, to which they firmly adhere. They have an irregular form and vary in size from a few hundredths of a millimeter to one or more millimeters. | According to Robin, they are composed of carbon- ates and phosphates of lime and magnesia. I believe it probable that the calcareous productions are a meta- morphosis of adipose substance, and that consequently they have generally their beginning in the fatty de- generation of the cells of the serotina; the coincidence of the calcareous production in the places where, nor- mally, these cells are found and their frequent occur- rence upon the uterine surface, where, shortly before CONCRETIONS OF THE PLACENTA. 391 delivery, many of these same cells undergo regularly fatty transformation, support such a theory. We may, however, consider doubtful such relation to the calca- reous granulations which we find on villi affected with fibrous degeneration, since these have not the char- acteristics of the concretions of the uterine surface, which have a pale yellow color and are formed of a fine granulous substance ; those affecting the villi seem like compact masses radiating in very sharp angles, almost vitreous, of a deep color in the inte- rior and brilliant upon the borders of the angles. There are also examples of, and I have myself found a few, calcareous concretions, and even ex- tended calcifications, of the parenchyma of the villi under the form of small calcified ramifications. CHAPTER XIV. ABNORMAL DEVELOPMENT OF THE PLACENTA. AutHoucH the complicated and successive phases through which the normal development of the pla- centa passes render probable many anomalies and marked modifications, still they have not yet been defined, much less demonstrated. When treating of syphilitic lesions of the placenta, I cited a morbid form which I called angioma of the decidua vera and serotina. This change might easily be classified in the category under consideration, and be reduced definitely to a phase of abnormal vascular- ization. As a further contribution to the subject, I now offer the description of a most interesting spec- imen which takes away all ambiguity and teaches much in relation to the irregularity and abnormal placental development. The specimen belonged. to an abortion at the fifth month. No lesion was noticed in its fresh condition, and not until microscopic exami- nation was made. After being hardened in alcohol and cut vertically, it showed, imperfectly formed, two layers, one, the more dense, towards the uterine sur- face, and the other spongy, having the normal pla- cental characteristics about the foetal surface. Microscopical examination of the sections showed that the development of the placenta was normal in the spongy portion, but that the villi had not yet DEVELOPMENT OF THE PLACENTA. È 393 reached the compact layer, and the development of the lacune was arrested in the state of their early formative process. The cells of the serotina preserved their form and ordinary size; the lacune were very small, and a few of them presented the characteristics of dilated vessels. Towards the uterine surface, a ute- ro-placental vessel, somewhat dilated, had no resem- blance to the lacuna. Towards the foetal surface, the dilatation of the utero-placental vessels had been ar- rested, and they were in the condition of ordinary ves- sels; yet nearer to the foetal surface, in the spongy portion, they had undergone the regular dilatation of true lacune in this whole portion of the organ. The commencement of the large lacune was easily de- fined in the midst of the villi which extended to the cells of the serotina and were surrounded by them. The parenchyma of the villi was slightly affected with hyperplasia of the cellular elements of its mucous tissue, that was arrested in its primitive condition. The cells of the serotina, even while forming the ex- ternal wall of the envelope of each villus, had not un- dergone any of the modifications which transformed them into the glandular organ. An analysis of these conditions shows that the phases of the development of this placenta had been inverted. In the internal uterine portion the commencement of the formation of the lacune had been suddenly arrested, perhaps because the villi did not descend between the sep- arations which limited them. On the contrary, the lacune were completely developed towards the foetal surface, and the cells of the serotina were attached regularly to the villi, without any of the.rapid changes which they undergo in being transformed into the 394 DEVELOPMENT OF THE PLACENTA. glandular organ, when even there are severe patho- logical lesions such as in the case of melanosis. The irregular development of the various parts of the placenta confirms, I believe, several facts indi- cated in this work and the preceding one, upon the formative process of the organ; but the most impor- tant result is, that in its evolution there may be anomalies of development capable of occasioning abor- tion. Pathologists and obstetricians have for a long time agitated the question whether the placental changes were the consequence or the cause of the death of the embryo. The greater number of modern authors agree that placental diseases cause the death of the foetus; however, some seek to substantiate the doctrine of Aristotle, namely, that the morbid changes of the placenta are due to the death of the foetus. Clinical observations having never established with certainty, whether in abortion the disease of the em- bryo has preceded that of the placenta, or vice versa, we must determine it upon other grounds. Now, lay- ing aside all hypothesis and limiting myself to simple deductions from the facts which I have mentioned, it seems to me that we may reach certain conclusions. The fatty change of the cells of the serotina, which proliferate directly from the anatomical elements of the uterus, and which we so often observe during the early months of pregnancy, is a very potent, if not the only, cause of true hemorrhage. It belongs en- tirely to the maternal organ, and the foetus, in these cases, is the victim of an original placental disease. We may demonstrate the same in cases of melanosis in which the anatomical elements of the foetus are at- tacked by morbid materials which come from the ma- DEVELOPMENT OF THE PLACENTA. 399 ternal blood. In cases which relate to circumscribed lesions of the foetal villi, the same certainly does not exist, since we may question if the disease is not con- sequent upon deficient or too abundant nutrition. «In some instances we may regard as very probable, that the lesions of the villi have their origin in the organic activity of the ovum and of the embryo, as, for ex- ample, in the hypertrophy of the chorial villi and in the cellular hyperplasia of their parenchyma, espe- cially when it is limited to only a few of the villi. But doubt always remains, and we cannot definitely deter- mine the question. Virchow and some others believe that the uterine irritations are communicated to the ovum. At first sight, in the case of the irregular develop- ment of the placenta which I have just described, we might believe ourselves authorized to affirm that the irregularity was the cause of the death of the embryo and of abortion. But the foetal villi also were not normal, so that we may believe that their imperfect and incomplete development was the beginning of the anomaly of the maternal portion of the placenta. ‘The close rela- tion between the foetus and the placenta, the intimate bond which unites the foetal to the maternal portion explain the difficulties which we find commonly in establishing where the disease began. If we consider the important placental functions and complicated evolution of this organ as the probable conditions of its lesions and of the death of the foetus, we must also take into account the very complex and admi- rable evolution of the ovum and of the foetus, and conclude that on this side also exist multiple ele- 296 DEVELOPMENT OF THE PLACENTA. ments of changes without the aid of the maternal organs. It suffices to fix a little our attention upon abdomi- nal pregnancies to form an idea ‘of the activity of the ovum, but it is not less true that the influence of the placenta upon its normal development is also great. Finally, we have not collected as yet sufficient pos- itive facts to settle, in all instances, so obscure a question, which some observations have even ren- dered much more difficult. When a dead foetus re- mains in the uterus, and when the placenta, or por- tions which remain, continue to develop isolated, the problem cannot be solved. I cited a case of this kind when treating of placental cysts. The maternal or- gan contained clots of blood which contrasted singu- larly with the condition of saponification beginning in the foetus. In this case the placenta was affected with a severe disease, the origin’ of which, the em- bryo having been already dead for some time, could not be determined. In various other circumstances less grave we have established the same fact. In short, we may conclude that the diseases of the maternal placenta have a greater significance and importance than those of the foetal placenta, in deter- mining abortions and premature deliveries. NEW RESEARCHES UPON THE ANATOMY AND PATHOLOGY OF THE PLACENTA OF MAMMALS AND OF WOMAN. I nave believed that a new confirmation, by new observations, of the results which I have for many years been laying before the Academy upon this sub- ject, will be in some degree acceptable to those anat- omists who, in Italy and abroad, have confirmed my investigations by their own. I cannot, however, fail to perceive that, notwithstanding my publieations, and those more especially of Romiti in Italy, of Turner in England, and Marcy in America, the great majority of anatomists and obstetricians continue to hold as true the doctrines which others as well as myself have shown to be erroneous. It was in England that my observations began really to enter the domain of science ; and this because the illustrious Turner, with repeated investigations and numerous works published from 1871 to 1876, fully confirmed all the fundamental observations which I had published as early as 1868. Thus it has hap- pened that many of the observations which really be- long to myself are attributed to Turner, and in the same way in Germany, those, which I had much ear- 1 Given in the form of three letters addressed to Prof. Albert Kolliker and published in the Memorie dell’ Accademia delle Scienze dell’ Isti- tuto di Bologna. Bologna, 1883. 998 PLACENTA OF MAMMALS AND OF WOMAN. lier made upon the so-called roots of attachment of the foetal villi in the placenta of woman, are assigned to Langhaus. I do not intend to reclaim for myself the priority of these observations, which indeed others have already attempted; as, for instance, Romiti, affirming that even illustrious German anatomists have published some of his observations without, however, crediting him. Still less do I propose to show how, especially by some in France, an account of my labors has been rendered in a manner truly strange and very far from true, — for time brings the remedy for these petty wrongs to which the votaries of science in Italy have for years been accustomed. In giving the results of my new researches, I have deemed that it might be, therefore, proper to inquire with some minuteness into the reasons which have led my opponents to er- roneous views, placing in relief the uncertainties and the open contradictions which they are forced to ac- cept as truth in following doctrines opposed to my own observations. Unhappily, among those who are adverse to my ‘observations must be reckoned one of the most dis- tinguished of anatomists and embryologists, Albert Kolliker. However regretfully, I am constrained to adopt the ungracious office of critic, and to combat the teachings which he, the head of an illustrious and famous school, has given, as well on the placenta of the mammifera as on that of woman. This is so much the more painful to me because, when my act- ual observations are confronted with the teachings of Kolliker's school, the discord appears so serious PLACENTA OF MAMMALS AND ‘OF WOMAN. 399 and far-reaching as to give to some minds ground for suspicion that the words used sound sharp, or less than reverent, toward the great anatomist. But facts, not words, make the contrast To remove even the shadow of this, which I would consider an injurious suspicion, and to give clear and positive proof of the high esteem which I profess for the eminent anatomist, I wish to address to Kolliker himself these new investigations in the form of letters, knowing well that true and great scientists live only for the search of truth and its development. In the first of the letters I will show the causes by which the celebrated anatomical school of Kolliker was led into errors of opinion concerning the placenta in the non-deciduate and the deciduate mammiferous animals, The first question which I discuss is: How and why is it, since all recognize and assert that compara- tive anatomy alone seems to clear away the doubts and the great obscurity that surround the exact knowledge of the intimate structure of the placenta in woman, and since all have pursued the same path, that, at the end, they are conducted to opposite con- clusions? I believe that it is because, though the way prescribed was the same, they yet traversed it in opposite directions, the point which for the one party was the beginning of the journey being for the other party its end. Thus, Professor Kélliker, seek- ing to elucidate the differences observed in the devel- opment of the placenta in the mammifera, takes as the basis of his opinions certain conceptions held as correct about the human placenta; while, laying aside every preconceived idea, and ascending in my re- 400 PLACENTA OF MAMMALS AND OF WOMAN. searches from the simplest to the most complex forms of placentation observed in the mammifera, I avail myself of the knowledge acquired to judge the more complex facts observed in the placenta of woman, which I have found identical in structure with that of the superior simix. Entering into details, I show that, in the opinions held concerning the non-deciduate mammifera, the fundamental cause of error was this: that, to decide upon the existence of the organ in the uterus of the gravid females of the said mammifera, Kolliker set out with the preconceived idea that, if existing, it must present certain characteristics such as those ex- hibited in the human placenta, — that is to say, a cir- cumscribed structure and much vascularity, characters which are necessarily wanting in the non-deciduates, where the placenta is diffused, or which do not corre- spond with any exactness in cases where the placente are multiple, as in the ruminants. The admission of the preconceived general principle was, of necessity, followed by the error of affirming that the placental organ was wanting in these animals; while it was not the organ that was wanting, but there were wanting to the organ those characters of circumscribed mass (‘ mole”) and great vascularity observed in the placenta of woman. This first error necessarily led to a second, name- ly, the belief that, the placenta being wanting, ‘the foetal villi were received into depressions (glands) which were formed in the swollen mucous membrane of the uterus. On this subject I must refer to my past observa- tions, which have had wide and repeated confirmation oe PLACENTA OF MAMMALS AND OF WOMAN. 401 through investigations made by others in Italy and elsewhere, and by which it has been demonstrated that, after the act of conception, in some of the non- deciduates, from the whole internal surface of the uterus, in others at some points only of the surface, the epithelium falls off, and from the denuded surface there takes place a new formation of cellular elements (decidual), from which are formed, according to the different animals, either crypts or true glandular fol- licles, into which the foetal villi enter; that the said follicles, new-formed after the act of conception has taken place, remain in the uterus during the whole period of pregnancy, and disappear after parturition, the internal superficies of the uterus (the epithelial stratum of the mucous membrane being renewed) thus reassuming its condition prior to conception. In the deciduate mammifera, in which the placental organ has either the zonarial or the discoidal form, there exist the two general characters inferred from the human placenta; and here the fundamental cause of the errors taught by the school of Kélliker comes . from the supposition that, in these animals, as well as in the human placenta, that organ was developed by a transformation of the preéxisting uterine mucous membrane, with this difference only: that in woman the whole uterine mucous membrane was transformed, while in the deciduates it was only that portion of the membrane in which the placenta was developed. The new observations which I have made on the uterine horn of the Myoxus glis (dormouse) in a state of repose, in the period of heat, during pregnancy and the forming of the placenta, and at various epochs after parturition, demonstrate more fully the fact, 26 402 PLACENTA OF MAMMALS AND OF WOMAN. which I had previously remarked in gravid females, of other mammiferous deciduates (rodents and insec- _ tivora), — namely, that in some of these it is the whole uterine mucous membrane that becomes swol- | len and enlarged in the period of heat, and that after the act of conception it is not only the epithelial stratum that disappears, but all the elements which compose the mucous membrane (submucous connec- tive tissue, vessels, and glands) are completely de- stroyed to give place to a new formation of special cellular elements (decidual) from which the placenta will be formed. The new-formed parts being thrown off at parturition, the cavity of the uterus by degrees is clothed with a new mucous membrane, and so the “uterus returns to the state in which it was before im- pregnation. By these observations, which I minutely described and illustrated with plates, it is completely proved that in certain deciduates, at least, it is not a portion of the uterine mucous membrane that is transformed to produce the placenta, since this membrane, with its different component parts, is completely destroyed before the placental organ is formed. In other de- ciduates —as, for example, in the canide and the felidee — the destruction of the uterine mucous mem- brane does not occur even in the places where the placenta is developed; the epithelial stratum alone disappears, and thus in these animals is witnessed a fact worthy of special notice, because it serves to ex- plain the origin and the formation of the non-cadu- cous stratum of the placenta in woman. In the canide and the felida the uterine mucous membrane is furnished with a thick layer of loose PLACENTA OF MAMMALS AND OF WOMAN. 403 connective tissue, in the midst of which stand the numerous and long utricular glands. The decidual new formation in the place where the placenta is de- veloped closes their discharging apertures, and, as the secretion in them does not cease, the moisture sepa- rated becomes accumulated in their interior, and in the midst of the connective tissue they become de- formed, and acquire a degree of dilatation truly enor- mous. | In woman are repeated the same facts in the place where the placenta is formed, but the local conditions differ, as we shall presently see. Returning to the deciduates, the erroneous belief that the placenta was in these derived from a partial transformation of the mucous membrane would neces- sarily lead, as it did, to other and not a few errors of a secondary order. These demonstrate the profound differences observed in the intimate anatomical struct- ure of the placenta of different deciduates, as well in those having the zonarial as the discoidal form ; I re- ject the general character indicated by the intimate structure of the organ for those mammifera, namely, that the two parts constituting the placenta are so intimately united that both are thrown off in the act of parturition, while in the non-deciduates only the foetal'parts would be emitted, segregating themselves from the maternal parts. This observation, which is due to Weber, is per- fectly exact, but does not serve to distinguish the ani- mals from each other. By reviewing the observations of others and my own, it is easy to show that in de- ciduates, as well in the zonarial as in the discoidal pla- centa, the relations between the two parts of the pla- 404 PLACENTA OF MAMMALS AND OF WOMAN. centa are the same as are observed in the non-decid- uates, which is of simple contact, and not of intimate union between the two parts. } Thus it may be said that in the opinions held con- cerning the genesis and the structure of the placenta, both in the non-deciduate and the deciduate mam- — mals, the school of Kolliker was led into erroneous conclusions from the preconceived idea that in all cases the mucous membrane of the non-gravid uterus took an active part, representing the maternal por- tion of the placenta as simply swelling or becoming hypertrophic in the non-deciduates, or becoming par- tially transformed in the places where the placenta is developed in the deciduates. By my former and more recent investigations, how- ever, setting out from facts observed and followed in their minutest details, I have arrived at the opposite conclusion, that neither the mucous membrane as a whole, nor any of the parts that enter into its compo- sition, take an active share in forming the maternal portion of the placenta, and that in all cases this re- sults from a new formation of special elements, to which the mucous membrane of the non-gravid uterus does not always serve as substratum. An indispensable condition for the new formation is the denudation of the internal surface of the uterus, which is limited to the simple destruction of the epi- thelium in the greater number of instances precisely as was also observed in woman; but this indispensa- ble destructive process extends in some of the mam- -miferous deciduates to all the parts that form the mucous membrane in the non-gravid uterus, and the new formation is, in this case, established directly upon the internal muscular surface of the uterus. PLACENTA OF MAMMALS AND OF WOMAN. 405 In the act, or subsequent to parturition, the new formation that constituted the maternal part of the placenta is always more or less carefully expelled from the uterus, and the process of renewal, in order to restore the internal superficies of the organ to its state previous to conception, stands in direct ratio to the course of the aforesaid destructive process. It is with the new-formed decidual elements that, the villi or foetal vessels exclusively hold any relation. In the non-deciduates this relation is one of simple contact; but this same relation has been likewise ob- served in mammiferous deciduates, whether they have the zonarial or the discoidal form of placenta. In all these cases the decidual elements acquire, as the preg- nancy goes on, the form of a glandular organ more or less simple or complex; it is, therefore, not true that in the non-deciduates alone the foetal part separates itself from the maternal. In the mole, which is decid- uate, with the discoid form of placenta, the intimate structure of the organ is that of a cotyledon in the ruminants. In many deciduates, and in those in which the two parts constituting the placenta are intimately con- Joined, the decidual elements are proliferous, but re- main always in the state of cellular elements, and it is solely and exclusively with these that the vessels of the foetal part come into relation. Without prior decidual new formation there can in no case occur the development of the placenta, what- ever the form it assumes in the different species of mammals. Based upon mistaken observations of facts, the fundamental division of the mammifera into de- ciduates and non-deciduates was accepted by zoùlo- gists. 406 PLACENTA OF MAMMALS AND OF WOMAN. On this important point, however, I think no fur- ther discussion necessary, since the illustrious founder of the said distinction, Professor Huxley, has done me the honor of writing to me that he, too, has abandoned the distinction indicated. The nature of this review, moreover, permits me to touch merely, in passing, upon observations heretofore published, to show how the great differences of structure remarked in the pla- centa of vertebrate mammalia might readily reconduct to a unity of anatomical type, — an anatomical unity to which the physiological unity corresponds, — the foetal part, namely, or absorbent surface in contact with the maternal part or secreting surface. I will now examine the causes by which the ana- tomical school of Kolliker was led astray in its decis- ions concerning the intimate structure of the placenta in woman, which, as has been said, is identical with that of the superior simiz. The origin of the mis- takes with regard to woman is twofold. Some of them arise from the same idea that hindered a knowl- edge of the structure of the placenta in the mam- mifera, namely, that the decidua and the placenta are the product of a transformation of the whole uter- ine mucous membrane. Others have arisen from the fact that in studying the intimate structure of the organ the opinion has been derived from its examina- tion when completely developed, without taking into account the changes that must of necessity take place in its interior from the first. period of development, in which the two parts, maternal and foetal, which compose it, can easily be separated (as in the non- deciduates and in some deciduates), till the organ progresses and arrives at the second period or at com- PLACENTA OF MAMMALS AND OF WOMAN. 407 plete development, in which the two component parts are so intimately united as in no wise to admit of separation. My observations made on the formative process of the decidua and the placenta in the verte- brate mammifera warrant the assertion that if the de- cidua in woman was really derived from a transfor- mation of the preéxisting uterme mucous membrane, it would be a. fact quite exceptional for the human species, or, rather, which the human species would have in common with only the higher simie. Before undertaking to show the uncertainties and contradictions which one is compelled to accept as truths, — in entertaining the opinion that the decidua in woman is derived from a transformation of the uterine mucous membrane, and not from a neo-for- mative process, as in all the mammifera, — I would call attention to the not recent observations of Bischoff on the peculiarities of the mucous membrane in the uterus of woman, which he has from the beginning of his labors striven to place in clearer light. And let it be observed that although Professor Kolliker, in his “Treatise on Embryology,” repeatedly asserts that the decidua is developed by a transformation of the mucous membrane, without a hint of the peculiarities observed in this mucous membrane, he has yet re- corded and described them in his “ Treatise on His- tology.” But, without entering into minute particulars on this subject, which I have treated at length in my preceding works, I am content to notice one fact, unanimously recognized by anatomists, namely, that the mucous membrane in the uterus of woman does not present, and cannot be detached in folds from the 408 PLACENTA OF MAMMALS AND OF WOMAN. uterine muscular tissue beneath, as can easily be done in the ordinary mucous membranes of other organs. The reason of this fact consists in this: that the mu- cous membrane of the uterus in woman is not fur- nished with a rich stratum of submucous connective tissue, as is the case in the uterus of all the mam- mifera, the higher simize excepted. Now, this simple and general circumstance being | overlooked, and the assertion made that the decidua is derived from a transformation of the mucous mem- brane, as if this were an ordinary mucous membrane in the strict anatomical sense of the word, occasion is given for not a few ambiguities and uncertainties. — “The decidua is,” according to the school of Kolliker, “nothing but the uterine mucous membrane trans- formed, and even in the first stages of pregnancy it is exclusively formed from the hypertrophied uterine glands.” And yet everybody knows that, when the fifth month is past, the decidua is detached from the ute- rus, and its component elements undergo regressive phases. Is it then, perhaps, that new uterine glands begin again to form? Surely not, since Kolliker him- self affirms that he has found them hypertrophied and immersed among the innermost layers of the ute- rus during the whole period of pregnancy. How is it, then, that they are transformed, and that from them alone the decidua is developed, if, at the same time, they remain hypertrophied in the uterus? Is it, then, only the stratum of submucous connective tissue that is transformed? But this, as has been stated, does not exist in the uterus of woman. Per- chaps the transformation is due only to the epithelial PLACENTA OF MAMMALS AND OF WOMAN. 409 stratum of the mucous membrane. But Kolliker him- self has shown that this disappears immediately after the act of conception. What part, then, is it of the uterine mucous membrane that is transformed to be- come decidua ? The decidua in the uterus of woman, as in that of the mammifera, is developed from the elements of new formation called deciduates, which derive their origin from the capillary walls of the vessels that re- main uncovered by the denudation of the epithelium. Nevertheless, these cellular elements are not found opposite to the discharging apertures of the uterine glands. The hypertrophic condition of these and the fact of the hypertrophy attest their increased func- tional activity, and the moisture separated from them must necessarily make a passage for itself through the surrounding new-formed cellular elements. The apertures or outlets of the decidua, however, are not glands, as is believed; they are the openings that correspond to the discharging mouths of the said hypertrophied glands in the uterus. But, moreover, in that portion of the decidua against which the ovum rests, and which, therefore, will become the ma- ternal portion of the placenta, every trace of glands is very quickly lost, as Kolliker himself asserts. The reason of this singular fact, in a part which has been declared to be exclusively formed from the hyper- trophied utricular glands, deserves to be sought for, —all the more, since in the subjacent stratum which touches the uterus evident traces of altered glands are found, even when the pregnancy has reached its term; and the reason is found in the altogether special form which vascularization assumes in the placenta of 410 PLACENTA OF MAMMALS AND OF WOMAN. woman, —a form of vascularization that completely wastes away the glands. Now, Kolliker tell us, in the said part, the glands have already disappeared before the completion of the first month; and as we know that the special form of vascularization — vascular aneurism, that is, or lacune — is not established until about the third month, an effect is thus ascribed to a cause which, at the very time when it was supposed to be operating so energetically, did not yet exist. From what has heretofore been said, it clearly ap- pears that, for me to proceed in the minute criticism of separate particular facts, in order to exhibit the uncertainties and contradictions which they include, it would be necessary to quote Kolliker’s work in great part. It will be sufficient to mention that the examination of the well-developed uterine decidua, observed in cases of extra-uterine pregnancy, con- vincingly show that in woman, as in the deciduates and non-deciduates, the decidua is developed by means of a neo-formative process, and that the new- formed cellular elements take their origin from the walls of the capillaries. I have studied the changes which the uterus under- goes from the arrival of the ovum in the uterus up to the complete development of the placental organ in that portion of the decidua against which the ovum was arrested. I thus know how those who defend . the transformation of the mucous membrane are themselves forced to recognize a process of active proliferation in the decidual elements to account for the formation of the decidua reflexa. Held by this, the ovum is fixed against the new-formed decidual elements, which are vigorously proliferous, and with PLACENTA OF MAMMALS AND OF WOMAN. 411 the ovum form the obstacle to the exit of the fluid separated by the underlying utricular glands. These glands are, from the pressure exercised by the sepa- rated fluid, dilated and altered; thus are developed the two strata constituting the uterine or maternal part of the placenta, the spongy stratum near the uterus, or the non-caducous portion of the placenta of Kolliker, formed from the altered utricular glands, evident traces of which may be observed even at the termination of pregnancy ; and the stratum over this, developed from the new-formed decidua, or the cadu- cous stratum of the placenta’in which there never are traces of glands, because there never were any glands there. It is in this stratum that the placenta is formed; and all anatomists agree in recognizing that in the first months of pregnancy this is developed from a mass of cellular or decidual elements, traversed by a vascular network with endothelial walls only, and that among the said decidual elements the foetal villi are buried. This is the first period of the development of the human placenta which is observed in the first three months of pregnancy ; and as long as it lasts, the foe- tal part can be separated without laceration of the maternal part, as happens in the mammiferous non- deciduates. The second period of development, in which the organ is perfected and completed, and which renders it first difficult, and, later, impossible to disjoin the foetal portion from the maternal, begins, by the uni- versal consent of anatomists, with the establishing of two facts— the rapid and exuberant proliferation of branches from the trunks of the villi, and the ectasie 412 PLACENTA OF MAMMALS AND OF WOMAN. process in the network of the maternal vessels. Now, these two facts occurring contemporaneously in a lim- ited and circumscribed space, as the result of simple physical and mechanical laws, it must necessarily fol- low that the branches of the proliferating villi should press against the endothelial walls of the vessels, which . are at the same time dilated ; and the ultimate result is, that the walls of the vessels, at first simply bent in toward the internal cavity of the dilating vessel, must, as the process of aneurism becomes more and more pronounced, completely invest the villus the more, as this fact is helped by the tension exercised upon the walls of the vessel by the proliferous branches of the villus. That this takes place has been heretofore ob- served by Weber and by Virchow, when they de- scribed in human abortions the occurrence of tufts of villi making complete hernia in a maternal vessel. It is not possible here to sum up in a few words the observations which I have made, and to follow mi- nutely the succession of these facts in the develop- ment of the human placenta. It will suffice to point out how the observations of Weber and Virchow give, in what may be styled a rudimentary form, the exact conception of the intimate structure of the completely developed human placenta, because as in this there is the appearance of the foetal villi swimming in the blood of a lacuna, it may likewise be the case in the observations cited, while in reality it is the villi that have caused hernia in the lumen of the dilated vessel, bending inward the walls at the place where they seemed to penetrate. With these views, all the uncertainties sata incum- ber the knowledge of the intimate structure of the PLACENTA OF MAMMALS AND OF WOMAN. 413 placenta of woman entirely disappear, and it is no longer necessary to suppose the penetration into the interior of the placenta of two plates, the one called by Wincler fundamental, the other of inclosure, the placental caduca and the subchorial stratum of the placenta, according to Kélliker, who does not himself know when they have been transmitted thither from the decidua and the reflexa. The explanation is clear that the so-called lamina of inclosure is not continu- ous, this depending on the arrival or non-arrival at the chorion of the wall of the enlarged vessel resem- bling the lacune. It is no longer necessary, in order to understand the formation of these last, to have re- course to the hypothesis that the villi, in proliferating, corrode the maternal tissue and the walls of the ves- sels, determining a sort of physiological hemorrhage. There is reason for the internal divisions of the pla- centa being constituted of two plates, although they spring from one uniform and continuous stratum. It could not be otherwise, since they represent the walls of two adjacent enlarged vessels, furnished on their external surface with the decidual elements which these vessels elaborate. There is also reason for the manner in which are formed the so-called roots of attachment, the dis- covery of which has been erroneously attributed to Langhaus. In short, by substituting the observation of the neo- formative process of the decidua for the imaginary doctrine of the transformation of the preéxisting mu- cous membrane, and by following the formative proc- ess of the placenta from its first to its second phase of development, not only are all the uncertainties and 414 PLACENTA OF MAMMALS AND OF WOMAN. all the errors avoided, which are generally taught at this time, but there is acquired a simple and clear acquaintance with the histological structure of an or- gan so important, not merely in woman, but also in all the mammifera. i As to the human placenta, it may be said that the chief difficulty of the question is contained in the opinion held upon the nature of the external clothing of the foetal villi in the placenta at term. I have demonstrated that this investment is supplied to the villi from the mother. By Kolliker, such an assertion is not even to be discussed, because the foetal villi are covered with a peculiar epithelium from the first moments of ‘their development. Apropos of this we would call attention to the strik- ing differences of form and size between the true foe- - tal epithelium, clothing the villi during the first period of development in the human placenta, and the cov- ering shown by the same villi when the placenta has completed its phases of development, thus, for the most part, overthrowing Kolliker’s reasoning. But the clearest and most convincing proofs .for confirming my conclusions are drawn from the obser- vations made in the field of comparative pathological anatomy. By these observations I am enabled to confirm the opinions offered upon the intimate normal structure of the placenta in the mammifera as well as in woman. As an illustration for the mammifera, I found the maternal portion of the placenta at the close of preg- nancy in the uterus of a female Myozus glis (dor- mouse), in which that part of the organ continued to PLACENTA OF MAMMALS AND OF WOMAN. 415 develop in three segments, besides the ten which were full, notwithstanding that in the said three the embryos had died at the beginning of the pregnancy, the foetal part of the organ had been necessarily ar- rested in its development, and that part atrophied which was developed before the embryos died. Professor Cesare Belluzzi furnished the material for an analogous observation obtained in a woman who was delivered of a. nine-months placenta, to which was united, by an atrophied cord, a small shrunken embryo, of about the size of the human foetus in the second month of intra-uterine life. The examination of the foetal villi in this placenta showed that the pa- renchyma of the villi was atrophied, and here and there changed by a chalky, granular degeneration, and that the so-called external epithelium of the villi was notably enlarged by hypertrophy and hyperplasia of its cellular elements. Since it would be absurd to believe that certain elements of a dead part might not only live, but be proliferous, this observation fur- nishes an evident demonstration that in this woman were repeated the conditions found in the Myorus gls, namely, that the maternal part of the placenta had continued to develop after the death of the embryo, and that, consequently, the hypertrophic covering of the foetal villi can be maternal only, and not foetal. ‘The examination of two human placenta that re- mained in the uterus after parturition “ at term,” the one for two, the other for three months, offered me a favorable opportunity to make comparison with the aforesaid observation, and to exhibit the differences met with in conditions that may be styled analogous: _ when the maternal part of the placenta overruns its 416 PLACENTA OF MAMMALS AND OF WOMAN. ordinary phases of development, and when the life in it is maintained beyond the ordinary term by an accidental cause. For proof that the exterior covering of the foetal villi is furnished by the endothelial walls of the pla- cental vessels, and by an external stratum of the de- cidual cells elaborated from their walls, I offer my own observations, largely confirmed by Professor Ro- miti and others. Such observations are not difficult to make in examining villi of placenta of human abortions, in which, through the alteration of the parts that determine the abortion, a state is kept sta- tionary which is only transitory in the normal condi- tion, — that is, the persistence of the chorial epithe- hum of the villus, although it may be surrounded by the maternal covering which remains separate from it. To complete, from the pathological point of view, the .observations and the conclusions reached upon the intimate structure of the human placenta, I would cite the anatomical lesions observed in a syphilitic placenta at term, in which I found the process of in- filtration of lymphatic cells, and of complete mucous or colloid degeneration in the portion called by K6l- liker caduca of the placenta, and which, by universal consent, exclusively appertains to the mother. I ob- served the same pathological process in the so-called epithelioma of the villi in woman; and it is evident this process of infiltration of new elements, and sub- sequent colloid degeneration, which determines a swelling of the external wrapper of the villi, has been by learned writers designated by the improper name of deforming hypertrophy of the villi. My labor thus ended, I turn to the illustrious anat- PLACENTA OF MAMMALS AND OF WOMAN. 417 omist to whom I have addressed these letters, confi- dent in the belief that he will at least concede that I have not been prompted by a selfish personality in thus controverting his views taught upon this subject, but that, the rather, I was drawn to it by the love of truth, and that, after long and repeated investigations, I have felt bound to obey the first duty of inquirers, whether great or humble, namely, to act in the best way possible to them for the discovery and promotion of truth. 27 TT | | | EULOGY DELIVERED AT THE FUNERAL OF THE COUNT, KNIGHT-COM- MANDER, PROFESSOR GIAMBATTISTA ERCOLANI. By PROFESSOR GIROLAMO COCCONI. THE profound sorrow felt by Bologna at the sad announce- ment of the irreparable loss of Giambattista Count Ercolani, calls us to-day, reverent and desolate, around this bier for the last farewell to the illustrious and excellent citizen. But it is not the mourning of Bologna only ; all Italy with emotion lifts the funeral shroud, and salutes the corpse of one of her most famous and favorite sons. Wherever darted the swift, electric fluid, conveying the sad intelligence, a cry of grief burst from all who knew the man or his reputation. Scientific academies, universities, bodies of learned men, politicians, civil and military authorities, civic, municipal, and provincial associations vie with each other in rendering this tribute of respect, affection, and sorrow to the man who had such claims on the public regard. The press of the city, every class of liberals in politics, are unanimously showing the general grief. An eminent scientist, an upright citizen, a fearless patriot, Felsnia boasts of having given birth to this patrician who sought fame in the results of study rather than in the federal parchments of his ancestors. Educated in the school of the great Antonio Alessandrini, whose learned diligence he early imitated, in the most la- mentable poverty of means, he contributed to the foundation of those monuments of surprising activity, the museums of comparative anatomy, and veterinary pathological anatomy. PROFESSOR COCCONIS EULOGY. 419 But this youth of so brilliant promise Bologna lost in 1849, for he belonged to that pleiad of distinguished patriots who were guilty of having loved Italy, when, with the evil rulers who kept it enslaved and divided, the love of country was counted a crime. The events of 1848, the historic incidents of August 8th, and the memorable defense of Rome in which he took part, found him warm with this holy sentiment. When the last bulwark of Italian liberty fell by the arms of the French Republic, and the Sacerdotal power was re- established, Ercolani, as a member of the Roman constituent assembly was driven into exile. He repaired with other Bolognese to Tuscany where the régime of the Restoration seemed milder; but the persecu- tion of the government that was constituted in the name of the Pontiff was not confined to the limits of the State; it could not tolerate in a neighboring territory an asylum for the banished, and by constant pressure exercised upon the mind of the Grand Duke obtained from him the dismissal of all the patriots who had taken refuge in his dominions. Ercolani, obliged to leave the Tuscan territory at twenty- four hours’ notice, went to Piedmont which alone held aloft and honored the Italian flag. There, with scanty means, he dwelt in a poverty sweetened by the sympathy of his wife and a beloved child, and by the friendship of the most emi- nent patriots throughout Italy. But his mental endowments were quickly recognized, so that being by royal decree made a Piedmontese citizen, the government conferred on him the office of Assistant Professor in the Veterinary School of Turin, with trifling salary in- deed, more not being allowed in the financial condition of Piedmont after the disaster of Novara. Our Ercolani was, however, by no means discouraged. On the contrary, with the feverish activity which always distin- guished him, he was able, even from this humble position, quickly to emerge, and to make himself known to the scien- tific world. 42.0 PROFESSOR COCCONI’S EULOGY. Among the principal works of this period are especially his “ Researches Historic and Analytical on the Writers of the Veterinary Art,” a critical and biographical work en- tirely new, by the publication of which, ancient manuscripts existing in various libraries were brought forward and inter- preted. With difficulty Professor Carlo Lessona, of Turin, founded in 1852 the first Italian journal of Veterinary Medicine for which, even then, the illustrious Professor Herring found words of praise and encouragement. But the destinies of the country which, in 1849, appeared so adverse, brought forth, ten years later, that grand epic poem in action, from which Italy shone out one and inde- pendent. In the first days of this unity, the minister Mamiani, re- arranging the two veterinary schools of Turin and Milan, nominated Professor Ercolani to that of Turin. So that, from the lowest of the professorships, the lowest in seniority and compensation, he sprang to the highest position, which his deep learning had procured for him. But a grievous family misfortune was quickly to bring days of renewed wretchedness, and to plunge again into sorrow the life of the poor Ercolani. His only daughter, the flower of his house, the comfort of her parents in long years of mis- fortune, who, although married, lived with her husband in her father’s family, suddenly died when but little over twenty. The parents, stunned and unable to endure such a loss, repaired to Bologna, bearing with them the anguish which can never find relief. Thus the school of Turin lost its il- lustrious Director, and science also seemed menaced with the loss of one of its most ardent votaries; Ercolani, in the trouble of his mind, having firmly decided to withdraw from teaching. But the minister of that day, to whom it was highly important that Ercolani should not be lost as an in- structor, releasing him from the duties of Director and Pro- fessor of the school of Turin, appointed him regular Profes- PROFESSOR COCCONI’S EULOGY. 421 sor of the Veterinary Institute in this illustrious University of Bologna. Here he attained the highest offices, being several times President of the Medical Faculty, and twice Rector of the University. His indefatigable industry and his love for zo6tomical sci- ence did not permit him to drag out life in the mere germ of a veterinary school, carrying on alone the teaching ot the various branches, and hardly aided by a single assistant. Hence he conceived the idea, and gradually attained it, of endowing Bologna with a complete superior school of veter- inary medicine. Aided by the liberality of the Province, and by govern- ment grants, he was enabled to enlarge the ill-adapted build- ings, to erect new ones, and to procure the better accommo- dations that were demanded in order that the school might be adequately equipped for its purposes. The shortness ot the time that separates us from his death, the grief which oppresses our minds, deprive us of the ability even to enumerate his works, most of which are inserted in the memoirs of the Academy of Bologna. It suffices to say that, endowed with an exquisite acuteness of intellect and with an iron will, he spent almost his whole life in subtle investigations, aimed at raising the edges of that veil under which Nature conceals herself in her choicest workings. That he was a decided microscopist, when the microscope was in the hands of few, and an impassioned fol- lower of both medicine and surgery, as well as of natural history, is shown by his numerous discoveries in the field of normal and pathological histology, of comparative teratology, of elmintology, of pathological anatomy, of embryology. In a very learned work of historical and bibliographical curiosities, he restores to Carlo Ruini, a Bolognese senator, ‘ the glory of the discovery of the circulation of the blood, this, too, carried off by foreigners, who assign it to Harvey, a physician in the time of Charles First of England. Noteworthy among his many works are his patient “ Re- ADR PROFESSOR COCCONI'S EULOGY. searches on the Genetic History of Trematodic Worms, and the Adaptation of their Species to the Surrounding Fluid,” in which is shown his great skill as an observer and naturalist. “The Formative Process of the Osseous Callus in the Dif- ferent Fractures of the Bones of Men and Animals;” “ The Interior Structure of Tendinous Tissue, and that of the Fi- brous Tissue ;” The Transformation of the Histological Elements in the Animal Organism,” and other works of minute anatomy, attest his skill as a histologist. But the work that gained most attention from the learned of both continents was a series of papers regarding The Intimate Structure of the Placenta in Woman compared with that of other Animals ;” observations which led him to de- termine the unity of anatomical type and of nutritive func- tion of the foetus in all the vertebrates. These works, of which we are at a loss to say whether they most exhibit his acuteness of observation, his intellectual strength, the exactness of his deductions, or the vast extent of his knowledge, were reviewed in many foreign languages, and honored with a literal translation into English by Dr. | Henry O. Marcy, of Boston, in order that the book might be in the hands of the physicians of England and the United States. In opposition to the universal applause with which the scientific press received the discoveries of Ercolani upon the structure of the placenta, one of the most famous anatomists and histologists of Germany, Kolliker, maintained the old doctrines, and did not accept the new observations and infer- ences of Ercolani. The latter could not leave unanswered the objections of such a man as KGlliker, and published three long letters, rich with new facts and observations drawn from the fields of comparative and pathological anatomy, which, with much courtesy of manner, he addressed to his distin- guished opponent. And in this last work, which fell from his pen when the cruel disease which was to slay him had already developed PROFESSOR COCCONTS EULOGY. 423 its deadly germ, in this his profound learning especially shone, like a torch which flashes brightest before it is extin- guished. But among the most important scientific treasures which he left as results of his intellectual labors should be reckoned a valuable collection of works on the veterinary science, rich in manuscripts and rare editions, patiently collected by him in the course of many years, and sometimes at heavy cost, a collection which would have been unfortunately scattered if he had not, with munificent forethought, secured it for one of the libraries of this learned city. His wide reputation had made him a member of the prin- cipal national academies, such as the Royal Academy of Turin, the Lombard Institute of Science and Letters, the Academy of Science, Literature and Art of Padua and of Palermo, the Medical and Surgical Academy of Genoa, the Physical, Medical, and Statistical Academy of Milan, the Academy of the “ Quirite” and that of Agriculture of Flor- ence, the Scientific and Literary Academy of the “Con- cordi” and that of Physical and Mathematical Science at Naples, the Medical and Surgical Society of Bologna, of which he was also President; the Royal Society and Na- tional Academy of Veterinary Medicine of Turin, of which he was honorary President; and many others which escape recollection. But strangers also wished to adorn his name. ‘Three foreign veterinary schools, that of Stuttgart, of Dorpat, and of Kasan, named him honorary Professor. He was a mem- ber of the French Academy of Medicine, and of the Central Society of Veterinary Medicine of Paris, of the Royal Acad- emy of Belgium, the Imperial Academy of Berlin, the Veterinary Society of St. Petersburg, the Royal College of Veterinary Surgeons of London, the Numismatic and Anti- quarian Society of Philadelphia, the American Medical As- sociation, the Boston Gynecological Society, the Veterinary Union of Wirtenberg, and he had a friendly correspondence with the most eminent European scientists, among whom 424 PROFESSOR COCCONIS EULOGY. may be cited the great names of Virchow, Owen, Turner, and Milne Edwards. Such, in short, was the patriot, the man of science. What was the citizen? The object of public esteem, he was a member of the mu- nicipality of Bologna, and provincial Councillor, President of the Agrarian Society and of the local committee, member of the Provincial Sanitary Council, offices which he filled with love and honor. Though a student, and apart from the strife of politics, he three times accepted a deputation to Parliament, not to sat- isfy a devouring ambition, but from loyalty to the party to which from conviction he belonged. He sat always “on the Right” from deference to his honorable political friends, and because his tendencies drew him to that party which had — united the great Italian family. He took no active part in parliamentary labors; the scientific life, to which he was now devoted, not tolerating occupations foreign to study, and re- coiling from the barren party strifes that are carried on in the parliamentary arena. Deeply convinced of the goodness of our institutions, sin- cerely liberal, abhorring doubtful measures, jealous of med- dling with internal arrangements, he appeared to oppose the Important reforms which were introduced by the ministers “of the Left.” But this was not in him a blamable venting of systematic opposition, rather was it a natural result of excusable preferences and firm convictions. The Italian government held him in high esteem, and availed itself of his wise assistance in many important con- tingencies. The high renown which he had acquired in the sciences, and his services procured him many honors. He was Knight of Civil Merit of Savoy, Knight Commander of the Order of Maurice, and of that of the Crown of Italy. He was a mem- ber of the Royal Commission for the publication of the clas- sics in the Province of Emilia, and the colleges of all the universities of the Kingdom, without distinction between medical and veterinary, twice appointed him to the Superior | Council of Public Instruction. PROFESSOR COCCONIS EULOGY. 42.5 Of such honorable tributes Ercolani was truly worthy, be- cause he did not seek them, nature having constituted him modest and disinterested. Affable in manner with all, and especially so with the young, not rigidly bound to routine, but scrupulous in the duties of instruction, he was beloved by the youth whom he had as pupils for a period of more than thirty years. Cordial with friends and inferiors, he strove as much as possible for the advantage of all without injustice to any. Men so excellent, intellects so supreme, must not disappear, though they depart this mortal life. . But those inmost secrets of the organism which Ercolani so many times sought to unveil by his minute researches seemed at last to rebel against him, fierce to destroy such ro- bustness of intellect and potency of investigation. Heart cannot endure to recall the sufferings that preceded his end — sufferings borne by him with touching resigna- tion. There cannot be imagined a more cruel torture, against which strove in vain all the resources of that ungrateful sci- ence which he had so much loved. With him gradually passes away a generation of deserving professors who, having for their mission the progress of sci- ence, as well as its teaching, leave the indelible impress of their steps upon the earth as they move across it. Adieu, Giambattista Ercolani ; science salutes thee for thy learned industry with which thou hast made the Italian name honored far and wide. Adieu, Giambattista Ercolani; Italy in thee salutes one of those excellent patriots who, with self-denial, exile, and martyrdom, prepared the triumph of her holy cause. Adieu, Giambattista Ercolani, worthy citizen; Bologna, from whose walls thou hast departed forever, salutes thee, her ornament and pride. Adieu, Giambattista Ercolani, illustrious professor, at- tended by the sorrow of the colleges of this ancient seat of learning — Bologna — famous for so many ages for the re- nowned men who resembled thee. 426 PROFESSOR COCCONI’S EULOGY. Accept these, our unadorned but sincere words, as a poor tribute of the love we bear thee. In this woeful affliction, fain would we find for Re: desolate companion, who in thee loses the last of those dear to her, some accent which might soothe her grief, but the word 2 upon our lips, for we also have need of comfort. BoLognA, November 19, 1883. £ er SS OO ee n INDEX OF AUTHORS. è ; PAGE Albinus, Bernhard S. (German anatomist and physician, 1696-1770) 79, i 114 Aldrovandi (Bologna, 1621) . - . : . . : - 48 Andreini, Dr. R. . j ‘ È 3 IAT Arantius (Julius Cesar, Bologna, 1530-1589) è , Thos Aristotle (Greek sa 384-322 B. C.) A MI AA? Aveling, Dr. J. H. . : : : 2 . : . 105, 106 Baer, Karl E. von (1792-1846) 7, 8, 29, 33, 36, 69, 75, 279, 289, 291 Barkow . : ; : : 5 1% Bartholin, homes (@ovenhasen, 1616- _1680) : : . - 79 Bassi, Professor (Turin) . - . . : - . - . 174 Belluzzi, Dr. 7 : ; STIA Bernard, Claude (professor of phpeioloayon in Paria! 1813- —1879) 55, 79, 80, 81 Berres . : : 3 . . 34 Bischoff, Flicodore Luci (Munich, 1807) Bh WO) Mes SEZIONI 6° 104, 123-125, 134, 187, 256 Blokham . > : : È : . 124 Boivin, Madame Brose 1834; 17 73-1841) _ : : : : 74 Bojanus . : . . . : 2 - 108 Bruch, Prof. R. ico Sage =) : : : SARI Bruck, Prof. R. (Strasburg, 1860) . . e 147, 155, 221, 222, 224 Burkhardt (Basle, 1834) . - : . : . «0 20 Burns (London) . 7 . . . : : : ar LOG Cavolini (Naples, 1787) . ia a - . » | -220 Cohnheim BRIO A RIT ceereatrs . + e BOD Colin (Paris, 1856) . : : . è 11, 27, 34, 35, 57 Colombo, Realdo (Venice, 1559) : : . : . . - 65 Coste, Jean F. (French physician, 1741-1819) . : : See 125 Cowper, William (English anatomist, 1666-1709) . at 428 INDEX OF AUTHORS. PAGE Creighton .~ . : . - x : mw Cuvier (French nape 17 73-1838) . ai | 86, 234, 235, 237 Diocles . : : : = AT Duvernoy, George Tare (French ee: ae e. 1777- A855) il a pee. 53 Edwards, Milne . z : x 3 È ae ee Engelmann, Dr. George J. (St. Liouîsi 1875) : ; . : . 106 Eschricht (Copenhagen, 1837) . 8, 12, 24, 53, 74,96; 125, 002/02 Everard (Middelburg, 1661) È : : : 2 = : 79 Fabricius, Girolamo of Acquapendente (Italian anatomist, Padua, 1537-1619) . . . 29,32,33, 48, 51, 52, 57, 66, 70, 72, 80, 178 Fallopius (Italian anatomist, 1523-1562) . : : : . 108 Farre, Arthur (Cyclopedia of Anat., London, 1858) 114-116, 126, 259 Florinsky (St. Petersburg, 1863) . : : : : è . 163 Galen, Claudius (Rome, 131-201) : ; : : 4. At, be Gamgee, Dr. Arthur (Edinburgh, 1864) . ‘ : x 54, 55 Hi Regnier van (Leyden, 1641-1678) . 3 ; 31, 68, 78 Gurlt, Professor (professor of surgery in Berlin, 1860- -—1868) 11, 13, 34 Haller, Albert (Berne, 1708-1777) 29, 32, 53, 68, 77, 95, 109, 113-273 Harting . : ; : ‘ 6 Le CZ Rouhault (member of Rona Mee dewey of Sana 1714) ; = 109 Ruini (Bologna, 1596) . A 5 ; . 5 298902 Schiff, Professor (Paris, 1866) . 6 : : . : È ISO Schlossberger (Tiibingen, 1855) . 5 o . - : È 54 Seiler i È È 3 4 : : : : . 104, 105 Severi, Dr. (1832) : . 7 . . : 59 Severin, Marcus Aurelius bore, 1645) > 5 : . 48, 80 Sharpey, William (professor of anatomy, London) 10, 13, 17, 34, 69, 70, 75, 105 Sinèty, De (Paris, 1876) , : é ° : È 2 é 259 Snape (London, 1606) ST, Mal Spiegelbere ae 1864) : : : 12, 13, 48, “49, 55, 59, 187 Stuart d : 3 : È 3 A : A Lia Trinchese, Prof. Salvatore . x 222 Turner, Prof. William (Edinburgh, 1876) 181, 187, 202, 210, 228, 230, 232, 236, 237, 245, 273, 290 430 INDEX OF AUTHORS. PAGE Velpeau, M. Alfred (Brussels, 1795-1867) . . . - 66, 69 Vesalius, Andreas (1514-1564) . : : . : . . 53 Vieussens, Raymond (1641-1720) . : . . 53 Vierordt (Milan, 1857) ° . . 89, 103, 104, 110, 115 Virchow, Rudolf (professor of pathological snacomys in Berlin, 1821-) 165, 251 Waldeyer (professor of pathological anatomy in Breslau) 181, 187, 247 Weber brothers : : 5 . . . - . Hiss Weber, E. H. (Leipzig, 1827-1867) 8, 10, 11, 16, 34, 70, 98, 104, 106, 124, 125, 134, 257, 288 Wepfer. È - - - 31 Wharton, Tete. (Aandtordara! 1659: 1610- “1673) . .67, 68, 78, 80 Winkler : 5 . - 2 ° 4 - -MUIRDI Williams, Dr. goa (1875) e e ot tl e e ° ° 106 INDEX OF SUBJECTS. Absence of the placenta and of the cotyle- dons in the gravid uterus of certain an- imals maintained by the ancients, 17. Acanthus vulgaris, 282. Achoria, mammalia, 225. Acotyledonous placenta: simple, 277- 280; villous and diffused, 281; compli- cated villous, 282; localized villous, 282. Albumen, one of the constituent elements of the cotyledonal fluid, 54. Albuminoid substances, 82. Alkaline albuminates, 55. Allantoidea, the placenta exhibits in all the groups the simplest form of diffused placenta, and is developed in structure by localization, 292-296. Allantois of the ruminants, 13; in kanga- roo, 228; increase of, 291, 292. Alveolar surface, 51. Alveoli of the cotyledons, 50. Amorphous matter of the grayish tissue of the uterine surface, 112. Amylaceous matter, 80. Analysis of the anatomical knowledge of the ancients relative to diffused pla- centa, 27-48 ; of single placenta, 34-40; of multiple placenta, 48-56; of the fluid secreted by the uterine cotyle- dons, 55. Anatomical structure of the placenta in the cow, the sheep, and the hind, 151- 160; truths taught by the ancients con- cerning the uterine mucous membrane, 32-38 ; structure of the villi, 116-122. Anatomists’ opinions upon the utricular glands, 6-11; opinions upon the uter- ine mucous membrane, 27-40. Anthropoid apes, 287. Anthropoide, 293. Anthropologists, observations of, 295. Apertures in the septa, 251. Appendix, 147-174 Arteries, 251. Artiodactyla, 293. Aves, 293. Baer, von, classification of mammals by, 291; doctrine regarding placental de- velopment, 279. Balenoida, 293. Balenoptera Sibbaldii, 281. Batrachians, intestinal glands of, 12. Bos taurus, 282. Bradypus didactylus and tridactylus, 286. Branching utricular glands, 10-15. Bursa, chorial, 197. Calices of the utricular glands, 62; of the new glandular organ, 153. Camelide, 293. Camelopardalis giraffa, manner of form- ing placenta in, 282. Camelus dromedarius, 281. Canaliculi, glandular structure of, 8-20. Canaliculus, 20. Cancerous cells, so-called, 112. Canide, 293. Canis vulpes and domesticus, 285. Capillaries, net-work of, 253; of the villi, 261. Capillary blood-vessels, 16. Capra hircus, 282. Carcharias, rudimental placenta of, 219. Carnivora, observations upon the glandu- lar organ of the, 140; intimate struct- ure of the placenta in, 188. Caruncles of the chorion separate easily from the uterine cotyledons in the de- velopment of the foetus, 48. Caseine, one of the constituent elements of the cotyledonal fluid, 54. Cat, changes in the uterine mucous mem- brane of, 158-164; formation of new glandular organ in the, 163. Catamenial decidua, established during menstruation, and highly developed during conception, 105; the product of materials elaborated by the utricular glands, 134. Cavia cobaya, placental development of, 167; transverse section of placenta of (Plate IV., Fig. 1), 198. Cells, metamorphoses of serotinal, 118; of embryonic, 82; of glandular, 80. Centetes ecaudatus, 286. Centetide, 293. Cercopithecus sabeus, 287. Cervus dama, capreolus, elaphus, axis, porcinus, mexicanus, 283. 432 INDEX OF Cetacea, 293. Cetaceans, uterine glands of, 10. Changes in the ovum in the rat during gestation, 193-198; in the uterine mu- cous membrane of the Cavia cobaya during gestation, 198-205. Cheirogaleus, 281. Cheiroptera, 292. Chemical composition of the cotyledonal fluid, 54. Cholaepus Hoffmanni, 286. Choriata, mammalia, 225. Chorion, villi of, 23-35. Chyliferous vessels, 79. Classification of the mammalia, 272-296; table of, 293. Conclusions upon the utricular glands and mucous membrane of the uterus, 130-136; upon the glandular organ of new formation or maternal portion of the placenta, 137-145; relative to the development of the decidua and pla- centa in animals and in the human species, 206-209; relative to the de- structive and neo-formative processes, 265-271. Cotilophori, 293. Cotyledonous placenta of incomplete vas- cularization, 151-157; with complete vascularization, 285 ; with complete vas- cularization and ectasia of vessels, 286. Cotyledons, maternal, 13; rudimentary, 18; diameter of uterine, 21; differences in volume during pregnancy, 48; devel- opment of uterine, 58; anatomical structure and functions of, in the cow and the hind, the, 57. Cow, rudimentary cotyledons of, 13-21; formation of placenta in, 150-153. Cryptal form of the new glandular or- gan, 281. Crypts, simple glandular, 10-18; placen-. tal in cat, 187-190. Cyclothurus didactyla, 287. Cynocephalus sphinx, lacunose ectasia in the maternal vessels of, 287. ‘ Dasyprocta aguti, 285. Dasypus gymnurus, novemcinctus, and sexcinctus, 286. Decidua, catamenial, 105, 134; human, 25; reflected, 107; serotina, 111-116; uterine and reflected, fusion of the two, 107; placentalis sub-chorialis and sen- Aeon 255 ; early researches upon, 12. Decidua reflected, serotina and vera, structure and function of, in the Cavia cobaya, 196-202. Defenders of the doctrine of the direct communication of the blood of the . mother with that of the foetus, 11-82. Delphinoidea, 293. Delphinus phocena, 281. Demonstration of the fact that there exist SUBJECTS. two species of uterine glands in some animals, 18. Destruction of the old uterine mucous membrane, 193. Destructive processes carried on during gestation, 196. Development of the placenta, 93-101; of the glandular organ of neo-formation, 138; of the utricular glands, 14-26. Diagrams representing vertical sections of the uterus and placental develop- ment of animals and of the human spe- cies. (See Atlas.) Diameter of transverse canal and of the utricular’glands, 14-21. Diaphanous fibrous tissue, 119. Didelphia, 280, 293. Differences in gravid and non-gravid ute- rus of torpedo, 220; in the diameter of the utricular glands, 21. Dilatation of the vascular loop during gestation, 170; of utricular glands, 11- 23 Discoidal form of the placenta, 282-286. Distinctions between the human placenta and that of animals, 121-129; among mammals, 225. Dog, typical form of the glandular folli- cles preserved in the placenta of, 93; section of the placenta of dog at term, 190. Dolphin, uterine glands of, 9. Duplicidentata, 293. Ectasia of chorial villi, 176; in maternal vessels, 268; in utero-placental vessels, 287. Ectasis of maternal vessels, 202. Edentata, some called deciduates, some non-deciduates, 289, 293. Elephas indicus, example of complicated villous placenta, 281. Embryo, development of, 82; nutrition of, 218. Embryonic cells, 82. Endosmose, fetal nutrition carried on by, 137. Envelopes, foetal, 28; of the parietal celis, 251. Epithelial buds of the villi, 261; cells, 81; layer, 14, 19. Epithelium, internal, 14; of old mucous membrane, 196; of the villi, 261; of maternal secretory vessel, 241; of the chorial villi, 176. Equus caballus and asinus, 281; example of follicular placenta, 285. I Erinacead®, 15. Erinaceidz, 293. Erinaceus europeus, example of discoidal form of placenta, 285. Exosmose, foetal nutrition carried on by means of endosmose and, 137. Experiments upon the uterina mucous membrane, 16-20. INDEX OF Expulsion of glandular organ in delivery, 142. Exterior membrane surrounding the villi, 116. External form of placenta, 287. Factors upon which the essential differ- ences in the structure of the two villi in the various forms of placenta in the mammalia depend, 239. Fallopian tubes, 104. Fecundation, 92. Felide, 293. Felis catus domesticus, of zonarial form, 285. Fibrine, one of the constituent elements of the cotyledonal fluid, 54. Filaments, lymphatic, 74. Feetus, nutrition of, 137, 172. Folds of the mucous membrane, 92. Follicles, simple, glandular, 2, 10, 18, 80; type of these, 42. Function of cotyledons in ruminants, 52; in animals with single placenta, 65. Fusiform cells, 116. Genesis of new vessels by vascular trans- formation, 128. Gestation, changes occurring in the mu- cous membrane during the period of, 15-20, 193. Glands, utricular, 9; two species of uter- ine, 16; increase in volume during ges- tation, 8-12; secretion of, 44. Glandular organ of new formation, 27- 46; cells of, 80. Glycogenesis, 80. Glycogenie cells, formation of, 56. Guinea-pig, development of the placenta in, 167; description of the fully formed placenta in, 198-202. Halicherus grypus, 283. Halicore dugong. 281. Hapale jacchus, 287. Hapalemur, 281. Bere, development of the placenta in, 66. Hepatic placental organ, 80. paid, development of the cotyledons, 5d. Hippopotamide, 293. Hippopotamus amphibius, 282. Histogenetic process by which glandular follicles are formed, 140. Histologists, opinions of, relative to the utricular glands, 6-16; the glandular organ, 26-38; in animals with multiple placenta, 47-57; in animals with single placenta, 65-81; upon the human pla- centa, 102-112, 177-181. Homo, 293. AI decidua, a product of exudation, 5. Human placenta, structure of, 102-129; 28 SUBJECTS. 433 peculiarities of, 121; lacunar circulation of, 127. Hyomoschus aquaticus, 281. Hyperplasia and hypertrophy of sub-con- nective tissue, 117-121. Hyracoidea, 293. Hyrax capensis, cryptal form of placenta in, 283. Ichthyopsida, 293. Implacentalia, applied to the marsupialia ; monotremia, cetaceans, 225. Insectivora, 234, 293. | Introflexion of the walls of the maternal vessels upon the villi, 257; of the epi- thelial layer, 180. Lacune, formation of, 257; upon the in- ternal portion of the uterine surface of the placenta, 122; placental, 145. Lacunar circulation of the human pla- centa, 127. Lacunose ectasia in the maternal vessels, 287; circulation, 145. Lamelle, uterine, formed by the eleva- tion of new tissue, 161, 162; representa- tion of, Plate X., Fig. 1(9, g, g). Lamina of the sub-chorial tissue, 251. Lemurida, 293. Lemur rufipes, villous placenta, 281. Lepilemur, villous placenta, 281. Lepus caniculus and timidus, 285. Lesion, traumatic, of uterus, 142; patho- logical, of placenta, 121. Lumen of utero-placental vessels, 184. Lutra vulgaris, 283. Macacus nemestrinus and cynomolgus, 287. Macropus major, 227, 280. Mammalia, different periods of nutrition in, 82; one law governing the forma- tive process of the placenta and the nu- trition of the foetus in all the, 217; em- bryonic phases of, 121; classification into Allantoidea and Omphaloidea of all the, 293; factors upon which depend the diverse forms of placenta in the, 239; two fundamental parts, one vascular and absorbent, the other maternal and secretory, in the placenta of all, 224; nutrition of the foetus during intra- uterine life, 137; classification into de- ciduates and non-deciduates, 279. Mammals, species of glands in, differing in structure, volume, and office, in all, 24, 131; single anatomical type of the placenta in all, 184; multiparous, 182; with diffused placenta, 212; classifica- tion of, 291, 293. Mammifera, uterine glands in, 6-27; im- placentalia and placentalia, 224-227. Manis, 296. Mare, utricular glands and uterine mu- cous membrane of, 6-38; development 434 INDEX OF SUBJECTS. of placenta, 97; vertical sections of gravid and non-gravid uterus, 36; changes over the whole uterine surface during gestation, 42-46. Marsupialia, classed by Owen with impla- centalia, 225; simplest form of placenta joined with the simplest but relatively higher form of diffused placenta found in the, 230-237. Membrane, existence or non-existence of the uterine mucous, 84; changes in the same, 106; functions of, 135. Memoir, placental development in all mammals, including the human species, 6-146. Metamorphoses of the cells of the serotina, | 118. Modifications of the new glandular organ in certain mammals, 140. Mole, uterine cotyledons of the, 154. Monacus albiventer, 283. Monkey, placental development in, 174. Monodelphia, 293. Monodon monoceros, 281. Monograph, unity of type in placental development, 176-271. Monotremia, 225. Muride, 293. Mus decumanus, 285; transverse section of a gravid uterus of, 193. Mus musculus, 285; segment of the gravid uterus of, 195. Mustela foina, martes, and vulgaris,283. Mustelide, 293. Mustelus levis, description of uterine horn, 219-222. Mycetes ursinus, 287. Neoplasm, cellulo-vascular, 193-195. Noctilio leporinus, 286. Nutrition, foetal, 54, 82; during intra- uterine life, 137. Observations of the ancients upon the utricular glands, 6-13; upon the villi of the chorion, 27-33; upon the uterine cotyledons, 47-52; upon the structure and formation of the placenta, 65-85. Omphaloidea, 292-294. Orca gladiator, 281. Ornithodelphia, 280, 293. Ornithorhynchus paradoxus, 280. Orycteropus, 283. Oviparous vertebrates, 219. Ovis aries, 282. Ovum, nutrition of the, 82; changes dur- ing gestation, 193; development of the, 163. Pachyderms, uterine glands of, 10; foetal and maternal placenta of, 29-31. Pangolinus, 281. Papille, placental, 27-34. Pedicle of the cotyledon, 60-64. Peduncle of the placenta, 200-204. Perissodactyla, 293. Phoca bicolor and vitulina, 283. Phyllostoma hastatum, 286. Phylogeny, importance of the study of the structure of the placenta relative to zoological, 290-296. È Pinnipedia, 293. Placenta, multiple, 47-64; single, 65-101; human, 102-129; conclusions relative to the maternal portion of, 137-145; formation of the glandular portion of, 147-174; histological unity of the ana- tomical type of, 176-218; unity of the physiological processes and office of the, 218-271; microscopical studies showing the unity of type of the, 277- 296. Placente, simple acotyledonous, 280; villous and diffused acotyledonous, 280; complicated villous acotyledonous, 281; localized villous acotyledonous, 282- 284; cotyledonous, 284; cotyledonous, of incomplete vascularization, 285: cot- yledonous,of complete vascularization 285. Plagiostomi, acotyledonous, 279; cotyled- onous, 279. . A Proboscidea, 293. Processes, destructive, 186; neo-forma- tive, 265. Propithecus verrauxii, 281. Pteroplatea altavela, villi of mucous membrane of the, 221. Pteropus medius, 286. Quadrumana, classification of, 293-296. Rabbit, uterine glands, 22-25; develop- ment of the placenta of, 90-93; changes in the uterine mucous membrane, 88- 96. i Raja torpedo, embryo of, 220. Rangifer tarandus, 283. Reptilia, 293. Rhinocerotide, 293. Rodentia, 293. Ruminants, difference of opinion as to the cotyledons of, 51-56; development of maternal cotyledons of, 58-64. Sauropsida, 293, 294. Scymnus lichia, 222. Selachii, villous neo-formation in the mu, cous membrane of the gravid uterus of- 277; viviparous, 219. Semnopithecus nasica and mitratus, 287. Serotina, differences of opinion as to the character and function of the decidua, | 108-114. Sheep, rudimentary cotyledons of, 154. Simiz, 287-291. Simiada, 293. Sinuses, placental, 122. Solipeds, lacteal fluid of, 231. Squalide, placenta of, 76. : INDEX OF Subungulata, 293. Suide, 293. i Summary, including anatomical facts as to the most remarkable differences seen in the placenta of the mammifera, with their application to taxonomy and phylogony, 272-296. Sus scrofa, 281. Talpa europea, 284. Talpide, 293. Tamandua, 296. Tamandua tetradactyla, 286. Tapiride, 293. Taxonomy, reconciliation of the embry- ology of mammals with, 294. Trabeca, cellulo-vascular, 197. Tragulida, 293. Tragulus Stanleyanus and meminna, 281. Troglodytes niger, 287. O, perivheral part of cotyledonal, 03. SUBJECTS. 435 Ungulata, 293. Uterus, utricular glands and uterine mu- cous membrane of, 6-26; formation of new glandular organ in the gravid, 27- 46 ; conclusions relative to the utricu- lar glands and mucous membrane of, 130-136. Veins, circulation of maternal blood in, are utero-placental, in human species, Vertebrata, 293. Vertebrates, oviparous, 219; mammifer- ous, 224. Vespertilio murinus and noctula, 285. Vessels, injection of fcetal, 190; utero- arterial and venous, 191; placental, 44. Villi, chorial, 10-30; structure of placen- tal, 113-121. Woman, development of the placenta in, 69-173. Tui AI Age vow eS * e eC pe rn "n FI IDI EP IID DIPS INIST ‘os b> RAISI N | sell N ASIA = & Ù è 1, . K = ig mi Î % a i I > ® x Petes _ otf Ù 9 > 9 - ye r . a a 7 È < Pe Li N) 2 p be + ‘ si i> x 7 is ai A È 3 \ » n s - - A - A 1 . - - E 4 La 3 " ’ x 7 7 i È a ) or # 7 4 4 = . > V a ig . à x = a n e 9 PA Se è » + 5 - > bs i E Pet - È - - SS - d ¥ x > E 4 = = . = > , x n 2 E Pac = 5 i x “ i Soe Sa LIE L - n 2 Ù b C . ye È , CSI - si = x a é i - è 3 o - 7 F . 3 e a 2 2 ga mr 7 Pt = * Y LS = pai Vr = 4 + . 5 > a va . i ‘ 3 ‘ N A x” 1 i È e. i - ~ = la - E; - ’ 1 x si ca - = ‘ Co 4 È di Sai - = è Sa sn - ie - >. - - fr! a - E - = ae = gi = n % ” ‘ - a & . - . 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