1. The ultimate purpose of nature, in associating the two sexes in the human species, is to bring to maturity and produce, in a fit state to live and procreate, a constant succession of individuals, that shall perpetuate the species to the end of time.

2. This object is invariably accomplished by one uniform series of laws and phenomena, which have been studiously inquired into, accounted for, and, in most instances, explained in a satisfactory manner, amounting almost to demonstration.

3. The study of the function of reproduction, in all the other classes of animals, affords no other nor any dissimilar evidence. On the contrary, both by comparison and analogy, the study in question serves to confirm us in the notion, that Man differs in nought, in this respect, from the animated beings placed below him in the scale of creation. One same primary intention is manifest in their sexual distinctions; the means to ensure the ultimate purpose—their perpetuation—are the same; the same laws and the same phenomena mark the appearance, the development, and the final production of successive generations of individuals.

4. Any deviation from those laws—any violent change in those phenomena—and, still more so, any impediment to the accomplishment of the ultimate purpose of Nature, is a defeat of her intention.

5. Such a deviation, change, or impediment may occur at any time previously to the period established for the appearance of a new and perfect being. If it occur at such a time as shall be incompatible with the maturation, and consequently with the life of the new creature, or even with its maturation alone, (although tokens of life be observed at the time in question,) a MISCARRIAGE is said, in common parlance, to have taken place; for Nature has miscarried in her undertaking: she has been foiled in her expectations.

6. In the reproduction of the human species, such an event might justly be considered to have occurred, if, at any time before the completion of the natural period of gestation, the foetus be expelled, whether dead or alive. But as in many instances, notwithstanding its premature expulsion, the foetus has grown and has continued to live its extra-uterine life, in spite of the want of maturity, (a case known to have occurred even so early as between the sixth and the seventh month,) the expression, before mentioned, (5) is not applied to any untimely expulsion of the foetus that may take place later than that period—at which, and after which, and till the completion of the ninth month of gestation, such an expulsion would be called a premature labour. The distinction, however, is more specious than useful: it is an offering to social etiquette, rather than to science.

7. The premature expulsion of the produce of conception before the seventh month, has also received the name of ABORTION. This denomination has been generally adopted, and is used by the writers of every civilized nation, ancient or modern, according to their respective languages. It is that which has been employed in the following explanations of figures taken from nature, which are intended to exhibit several examples of abortion in the human species.

8. The study of abortion, in this point of view, (7) is an infinite source of interest, whether considered in reference to science and the important question of generation, or simply in reference to medical practice. On the continent of Europe, and even in the States of America, but more particularly in Germany, the subject, under its two-fold aspect, has engaged the serious attention of some of the most learned philosophers and most skilful practitioners. I know of no other professed writer on the same subject, besides Burns, in this country. His work on abortion is brief, and more valuable for the practical suggestions it contains, than for any luminous or accurate view of the various scientific points connected with that subject. But like every thing which proceeds from the hands of that able practitioner, the performance is respectable.

9. It is impossible, thoroughly and accurately, to comprehend the mode in which abortion takes place, without being previously acquainted with the origin, formation, progress, and metamorphoses of the foetus, and its connection with the mother. On all these points, we have, until lately, been in the habit of professing the same articles of belief as our predecessors: we have repeated what we heard them say, or what we read in their writings; and many, both here and elsewhere, repeat still the antiquated theories respecting conception and the structure of the human ovum, which they have learned on the obstetrical benches.

10. The great advancement—the great and forward strides which physiology has made in France, as well as in Germany, have contributed to explode those antiquated theories. Acute and indefatigable anatomists have been busy watching Nature in all her movements, from the first moment of her calling the rudiments of a human embryo into existence, until her magnificent work has been completed by the production of a new, life-gifted, individual of the species. They have called to their aid the much improved art of microscopical observation, and have thereby succeeded in almost tracing the very earliest instant of embryonic existence. The register of their observations constitutes the biography of the human foetus.

11. It is with the view of contributing to the common stock of new and interesting information on this all-important question, that I bring forth the result of my inquiries into the morbid state of the human Ovum, and its structure under circumstances of premature expulsion. If such inquiries have led me to adopt the improved notions of the more modern physiologists and anatomists in these matters (which I have professedly studied, and have had the most ample opportunities of studying for many years); they have, likewise, enabled me to detect some of the oversights of those observers, and to add a little to what has already been brought forward; while, at the same time, they have induced me to join that class of writers who dismiss, as inconsistent with facts, the theories and assumptions of olden times, whose strongest authority has been their mere repetition.

12. The ideas which are now entertained respecting fecundation, after the successful congress of the two sexes, in the human species—respecting its seat—respecting the first origin, station, and rudimental creation of the embryo—respecting the journey of the latter into the womb, its sojourn in that cavity, and the various metamorphoses it undergoes therein, up to the period fixed for its projection into the WORLD, may be comprised within a small number of propositions. I shall support those propositions by references to facts, or the quotations of competent authorities, and the allegation of anatomical discoveries. But as the object of the present work is to illustrate abortion, and not the complete life-circle of the foetus, I shall stop the number of my propositions at the fifth month of its intro-uterine existence. After that period, the various phenomena of foetal gestation are so uniform, that they afford less matter of interest to the philosopher.

13. Conception, or that result which follows sexual congress, in virtue of which one, or more individuals, of the same species is called into being, takes place in the ovarium of women. This is doubted by Meckel and others, who look upon all cases of ovaric gestation (see Plates IX. and X, A. and B.) as mere accidents, and as only proving that if conception has not before taken place in the womb, it may take place in some other part connected with it; but the point has been set at rest by the more recent experiments and microscopical observations of Professor Boer, of Koenigsberg. I adopt his conclusions. Their correctness is corroborated by the interesting experiments of Prevost and Dumas, although these experimenters admit not that fecundation takes place in the ovarium.

14. The intended receptacle of the embryo is the Ovulum. An ovulum exists in all the vesicles of Graaf, which the ovarium of a woman, who has reached maturity, contains.

15. Viewed by means of a powerful microscope, the ovulum is found to consist of a small yellow spherical body, placed within the vesicula Graafiana, with the upper portion of which it is, internally, in contact; so that it does not float freely in the liquid of that vesicle. This contact becomes more and more intimate as the ovulum enlarges, when that part of the capsule of the vesicle which lies over it becomes, in a correspondent degree, thinner.

16. At first, the little yellow body, being rather opaque, is distinctly seen even without a magnifying glass; but as it advances, it becomes more transparent and, consequently, less distinguishable.

17. This little yellow body is a minute spherical mass, with a roughish or slightly granular surface, and is hollow. Its parietes are thick; around them is an envelope of a much thinner texture, which is distinctly seen, owing to a small space lying between it and the surface of the little yellow body, which space is filled with a fluid substance of a peculiar nature.

18. When FECUNDATION takes place, that part of the vesicle of Graaf to which adheres, internally, the ovulum, bursts, and the ovulum escapes with its external envelope, together with a small portion of the liquid peculiar to the Graafian vesicle, and thus it passes into the fallopian tube.

19. Independently of the external envelope, and within it, the microscope has detected, after fecundation, the existence of another covering, completely investing the little spherical yellow body.

20. The ovulum has been traced, after fecundation, into the cavity of the womb, where the external covering (17) becomes what Boer has called “the cortical membrane”, (cortex ovi of the present work,) improperly considered as a uterine production by preceding writers, and denominated the reflected caducous or deciduous membrane.

21. The more intimate covering of the yellow body of the ovulum, that which closely invests its surface, and appears only after fecundation, (19) is afterwards changed into what has been denominated the shaggy chorion: my observations and my plates shew this. Boer, however, professes not to know what becomes of it during the progressive intro-uterine development of the ovulum.

22. The hollow and spherical yellow body of the ovulum corresponds with the yelk or vitellus of the ovum of oviparous animals, and from it all the other several parts of the foetiferous ovum are derived or formed, as gestation advances, and a progressive development of the parts takes place, from within, without^[1].

23. The existence of the cortical membrane is proved in many parts of the present work, but particularly by Fig. 15, Plate III., and Fig. 17, Plate IV. in both of which specimens of abortion, the said cortex had persisted to a longer period than usual during gestation, and had become, consequently, thickened, opaque, fleshy indeed, and the cause of abortion. Figure 15, too, shews strongly the probability of my notion that the thin membrane investing the surface of the yellow body of the ovulum is, in good truth, what has been usually denominated the shaggy chorion.

24. Another proof, amounting to demonstration, of the existence of a cortical covering to the human ovulum, and that of the filiform envelope called the shaggy chorion within it, I find in a striking and beautiful preparation belonging to Sir Charles Clarke, marked 87. We there see a complete cast of the lining (caducous membrane) of the uterine cavity after fecundation, thrown off at a very early period, and with it the ovulum, (of the size of a Portugal grape,) exhibiting the cortex ovi, shelly and membranaceous, of a dense texture, yet flexible, which has burst like the pericardium of some seeds, and allows the shaggy chorion beneath it to be seen. It is a curious fact, that even Ruysch has, in his fanciful manner, represented a human ovulum of about three weeks with the cortex burst, yet still in situ, and the shaggy chorion beneath it, in every way resembling the specimen of Sir Charles Clarke’s in the Museum of St. George’s Hospital.

25. Even the errors of some of the very able anatomists of the present day come in beautifully to corroborate Professor Boer’s observations of the cortical membrane. Breschet and Velpeau, for instance, state, that within what they (with their predecessors) have looked upon as the decidua in the human ovum, there is a cavity containing a peculiar liquid which, in their opinion, is essential to the nutrition of the foetus. Now what is this but the very description of the ovulum by Boer (17), proving that there is a cortical membrane in the human ovum?

26. The cortical membrane is destined to be absorbed during the first months of utero-gestation, thus exposing the next membrane to the contact of the uterine lining (decidua), with which a connection takes place in that part where the placenta is to be formed. In that part, however, the cortex ovi is never altogether obliterated, but only made thinner; and, in process of time, it is converted into a mere pellicular envelope, which not only serves to divide the filiform vessels of the chorion into groups or cotyledons in order to form the placenta, but also covers all over those cotyledons or groups of vessels. (Plate I. Expl. of Fig. 1.) I have called this the membrana propria^[2].

27. While the process or metamorphosis of the ovulum noticed by Boer takes place in the ovarium, in consequence of fecundation, the cavity of the womb does not remain idle, but forthwith sets about weaving for itself a general lining—a sort of pseudo-textile membrane—which extends all over the cavity, descends partly into the cervix, and is often, (not necessarily always,) projected even into a great portion of the fallopian tubes.

28. This adventitious lining of the cavity of the womb is formed quite independently of the presence of the ovum, for it has been found in most cases of devious gestation, where the foetus was extra muros uteri (Plate VIII. IX. X. Fig. 1 and 2, and page 35), and has been found advanced in its progress of formation, while the ovulum was, as yet, on its way through the fallopian tube after fecundation. (Haller, Lobstein, Velpeau, Meckel, Pockels.)

29. To this adventitious lining described by many ancient authors, but by none better than by Harvey, the name of decidua already mentioned (24, 26) has been given by Hunter, because, viewed as a production of the uterus it is caducous and not permanent like its own natural lining; as, however, it is no more caducous than any other of the involucra of the ovum, the denomination is not strictly correct. It is, nevertheless, more generally adopted than that of epi-chorion, given to the same pseudo-membrane by Chaussier.

30. Its mode of formation and its structure have been differently explained by different authors. The explanation offered by Burns runs counter to facts and realities. That author speaks of all the minute steps of generation, with the same confidence as if all had been demonstrated. His imaginings respecting primary and secondary vessels shooting out from the inner surface of the womb to form the decidua must be gratuitous, as no other anatomist or physiologist, either before or after him, has been able to ascertain the reality of such a process.

31. It is probable that the decidua consists of two laminÆ, inasmuch as we always find it with one surface perfectly smooth and the other rough. If so, they are most intimately connected. It is at least one-twentieth of an inch in thickness during the first five or six weeks of uterofoetation, when its tissue is found to be more knotty, coarse, and full of short threads, (not unlike a very ordinary mat,) than a purely membranaceous or cloth-like lining would be. It is not until a more advanced period of gestation that the decidua becomes distinctly membranaceous, in which state it lines the entire cavity of the uterus. (Plate IX. and prep. 73, 75, 76, of Sir Charles Clarke’s Collection: also Dr. Agar’s beautiful specimen of impregnated uterus, Mus. Coll. Reg. Lond. Med., and several specimens in the College of Surgeons, particularly Sir W. Blizard’s case.)^[3]

32. Into this chamber, then, so lined and so prepared the fecundated ovulum, in the condition described by Professor Boer, is received after its journey from the ovarium through the fallopian tube.

33. The pre-existence of an ovulum in the VesiculÆ GraafianÆ, or Ovarian Vesicles—and its metamorphosis, after fecundation (14, 15, 16, 17, 18,) have been amply confirmed by Plagge of Bentheim, who published an account of his experiments and observations, illustrated by figures, in Meckel’s Journal of Physiology. (See also Prevost and Dumas, 3rd memoir.)

34. As soon as the Ovulum has departed from its vesicular nest in the Ovarium, the cavity which remains begins to fill up with a yellow substance, different in texture from the surrounding tissue of the Ovarium, and having, generally, a radiated centre of a whiter colour. This is the corpus luteum. (Plate IX., page 30 and 31; also, Spec. 3468 B and C, Gallery College of Surgeons, and Dr. Agar’s case Royal College of Physicians^[4].)

35. The presence of corpora lutea in the Ovarium of women, is always an indication that as many ovula have escaped from that organ; but it is not necessarily an evidence that the individual has been impregnated, as ovula have escaped without the congress of the two sexes.

36. It is inaccurate, therefore, to state that a woman has been pregnant because a corpus luteum has been found in one of the Ovaria after death, or to calculate the number of children she has borne from the number of corpora lutea so detected. Corpora lutea have been found in the Ovaria of very young girls, of unmarried women of the strictest virtue, in newly-born female infants, and lastly, in sterile animals, such as mules. (Brugnone, Joer. Roose.)

37. Sir Everard Home’s notion that the corpus luteum was formed first, and that, too, independently of sexual congress, and that the Ovulum was formed afterwards, is disproved by more accurate and recent observers. (Boer, Plagge.) There is reason to believe that Sir E. Home had been too precipitate in his inquiry^[5].

38. The Ovulum, on entering the womb, is about the size of a small pea. The cavity, on the contrary, into which it enters, from the very first, is of considerable dimensions. One cannot help being struck at this great disparity in the relative dimensions of the Ovulum and the cavity of the womb. When they first come in apposition, that of the latter is from ten to twenty times greater than that of the former. (See Sir W. Blizard’s case, Royal College of Surgeons, and Spec. 73, 75, 76, in Sir C. Clarke’s Collection^[6].)

39. The time at which the Ovulum enters the womb after fecundation is not precisely known. (Meckel.) The fimbriated end of the fallopian tube has been found actually applied to a Graafian vesicle after copulation. (Magendie.) An ovulum, containing the rudiments of an embryo has been observed in the human subject half engaged within the tube, and half still resting on the Ovarium. (Bussieres.) The Ovulum has been detected on its way through the fallopian tube.—(Burns, Haighton, Cruikshank, Prevost, Dumas.) It is said to have been detected in the uterine cavity on the eighth day. (Home.) Although it has lately been the fashion to doubt the accuracy of such a fact, there is reason to believe it to be correct, from the circumstance of M. Bauer’s microscopian examination of that Ovulum and description of its structure corresponding with more recent discoveries. (Boer.) The embryo contained in an Ovulum of a week’s growth has been seen and measured. (Autenrieth Supplementa ad Historiam Embryonis Humani.) The Ovulum, until the eighth day, has been observed in the uterus under a gelatinous form by another anatomist. (Walker.) Ovula in the fallopian tubes have also been seen on the eighth day by Prevost and Dumas.

40. I have had occasion, within the last two months, to see a perfect Ovulum ejected from the womb fourteen days after a single sexual congress, which had taken place the day after the cessation of the menses. Dr. Pockels (Isis, December 1825,) examined more than fifty human Ova, among whom four had been expelled from the womb between the eighth and sixteenth day after conception. On the fourteenth day the Ovulum is about the size of a Spanish nut. The chorion is surrounded by a thick membrane^[7].

41. An Ovulum at three weeks is mentioned by Hunter (Gravid Uterus). At twenty-two days a perfect Ovulum, with the embryo clearly defined, was shewn by Dr. Combe to Dr. Baillie. Blumenbach asserts seeing an Ovulum of the size of a small cherry, which could not have had more than twenty-three days’ existence. M. Ogle’s case, published in the “Transactions of the Society for the Improvement of Medical and Surgical Knowledge”, was one of an Ovulum in Utero at five weeks. These facts contradict Burns’ assertion, that at “three weeks or a month after impregnation no foetus is in the uterus.”

42. After being safely lodged within the cavity of the womb, the Ovulum continues to grow on its own life-principle, for a while, until its connection with the mother is effected, through the medium of the deciduous membrane, which becomes, at a more advanced period, as it were, a new and additional covering to the Ovulum. The growth of the Ovulum causes the cortex to burst, as happens with the receptacle or cortex of certain seeds, and with the outer shell of the ova of some oviparous animals. (See Plate I., fig. 1, 2, 3, 4.)

43. On the cortex bursting, the lanuginous or fibrillous membrane within it (21) is exposed, when the fibrils will forthwith entwine themselves with the flocculi of the decidua, and thus the Ovulum fastens itself to the uterus by one or more contiguous points. (Carus.)

44. The membrane having these fibrils on its surface, has been called the Chorion—and from the circumstance that these fibrils, both before the cortex which lies over them has burst, as well as afterwards, serve to promote the nourishment of the foetus, I have styled it, the nutritive membrane or involucrum of the foetus. It has been so considered by Ruysch, who calls the villous side of the Chorion, “succosa nutritioni foetus inserviens.”

45. The fibrils of the Chorion have generally been considered as filiform vessels. When examined with the microscope, they appear diaphanous and ramiform; some of them terminate into little bulbs like the ampullÆ of the villosities of the intestines. These bulbs adhere so firmly to the cortex ovi, that when an attempt is made to detach them, many are lacerated. (Carus.) It is only when the cortex bursts of its own accord that they are set at liberty. (43.)

46. These fibrils, however, are not all vessels. Some are only suckers, others are real vessels. (Carus.) The existence of any vessels among the fibrils of the Chorion has been denied very recently upon the same ground, namely, microscopical observations. (Breschet and Raspail.) But there must be an evident mistake in such observations; for the actual progress of those filiform vessels, and their gradual swelling into large veins and arteries, at an advanced period of foetation, have been noticed in examining various human ova of different ages. (Lobstein, Velpeau, Dutrochet, and myself.)

47. The nutritive envelope or involucrum, or membrane (Chorion) of the Ovum is bifoliated. I have a beautiful preparation of the transparent membranes of the Ovum, even after regular parturition, which proves this fact. It is probably even trifoliated. (Dutrochet.) A fluid has been found between the two laminÆ of the Chorion. (Meckel.)

48. The internal surface of the Chorion is likewise supplied with fibrils, which connect it with the next and innermost involucrum of the foetus, called the Amnion. Between the fibrils or filiform vessels of the two surfaces, a communication is kept up by small vascular trunks which meander between the two laminÆ of the Chorion. (Meckel and myself.)

49. The vascularity of the Chorion is further proved by its diseases, chiefly of an inflammatory character, ending in the thickening of its texture. (Plate III., page 12—Plate IV., page 13—Plate V., page 17—and many other examples in this Work.) There is a preparation in Sir Charles Clarke’s collection which shews the vessels of the Chorion as evidently as if they were injected.

50. But the vascularity of the transparent membranes is proved further by fine injections thrown into the vessels of the ovaria of women; on which occasion a beautiful net-work of minute vessels is rendered manifest, forming a species of vascular ring around the VesiculÆ GraafianÆ. The same observation has been made by comparative anatomists. (Cuvier, Home, Lobstein.)

51. These facts, demonstrative and corroborative of the vascularity of the Chorion, (45, 46, 48, 49,) explain and account for the reality of that self-existing life-principle inherent in the fecundated Ovum (42), which detaches it from its nest (vesicula Graafiana), enables it to travel through the tube, to grow or expand while thus travelling, and to maintain that same power of growth and development for a short time after its reception into the womb, until its final and effectual implantation on the maternal stock (uterus).

52. The same holds good with regard to the amnion, or inner transparent membrane of the Ovum, which, although normal anatomy has failed, morbid anatomy has succeeded in proving to be vascular. (Plate VI. fig. 20, and Description, p. 19, and Remarks, pp. 20–24.) (Haller, Monro, Chaussier, Meckel.)

53. If it be true that the amnion is a vascular membrane, there is no difficulty in viewing it also as a secreting membrane. Hence the source of that particular fluid, to which the name of Liquor Amnii has been given, and in which the embryo is suspended to the end of gestation. (Plate I. fig. 4, but particularly fig. 7, 8, and 9, and Remarks.)

54. The amnion is a sac formed by the reflected epidermis of the embryo. (Velpeau, Boer, Pockels.) It does not exist before the twelfth day. (Velpeau.) At the eighteenth day it is found as a bladder placed on the back of the embryo, and continuous to it along its edges or sides and at its extremities. (Velpeau.) It has been distinctly seen on the twelfth day. (Pockels.) It is then not a concentric membrane within the chorion, but a vesicle, on the outside of which the embryo rests as on a bed. Until the day in question the embryo is connected to the vesicular amnion at the back, by a cellular transparent membrane. From that time till the sixteenth day the embryo progressively gets into the cavity of the amnion, which before was connected with the chorion by one of its piriform extremities, while the other conical extremity penetrates slowly into the albuminous fluid of the chorion. (Pockels.)

55. While the embryo is within the chorion (nutritive involucrum) and rests on the vesicular amnion, the former membrane, or sac, contains a reddish transparent fluid having the consistency of the albumen of an egg, (54.) with a colourless and very slender membrane crossing it in various directions. (Pockels.)

56. The progressive increase of the Ovulum, from the time of its quitting the Ovarium until it has stationed itself firmly within the womb, has been demonstrated (Magendie, Prevost). In examining, between eight and twelve days after fecundation, the female organs of such of the mammalia as are multiparous at a single gestation, one Ovulum has been found near the fimbriated end of the fallopian tube of one size; a little farther into the tube another of a larger size; and lastly, near to the uterine orifice of the tube, a third of a still larger size; shewing the relative progressive increase that had taken place in such Ovula subsequently to a single act of fecundation, and proportionate to the time employed by such Ovula in travelling to the spot in which they were found. (Prevost, and Dumas’s 3rd Memoir on Generation.)

57. While thus circumstanced, the Ovulum is never connected with the part through which it passes. On plunging that part into water, the Ovulum is found not only to rise to the surface, but to float. (Home, Prevost, Dumas.)

58. What stronger proofs need be required of the existence of an inherent life-principle in the Ovulum, which is, at one time at least, (indeed I suspect throughout the period of gestation,) independent of any connection with the parent mother? (Plate I., and several of the explanations of figures throughout the work.) Yet none of the earlier writers who adopted the Ovarian theory of generation have ever asked themselves this question: What supports the vitality of a fecundated Ovulum after it has left the Ovarium, and previously to its becoming connected with the womb? In fact, the subject had never been mooted, before the more modern physiologists took it up and satisfactorily explained it^[8].

59. That the embryo probably lives in utero in virtue of its own life-principle, even through the entire period of gestation, (51, 56, and 58,) is rendered probable by many facts related by unimpeached authorities, which go to prove that when the whole intact Ovum has been expelled at an advanced period of gestation, or at the natural termination of that period, the foetus has continued to live, and the circulation of the blood has not ceased for an instant during a space of time of from nine minutes to a quarter of an hour. (Roederer, Wrisberg, Osiander, and Meckel, who repeated the experiments of the latter.) It has been asserted by a venerated authority that in an intact Ovum, expelled at seven months, the foetus lived upwards of an hour. (Harvey.) The truth of this assertion is confirmed by very recent observers (Green, Velpeau, Gardien, Dr. Campbell)^[9]. I once destroyed a female cat by prussic acid near the time of parturition; and having removed from the horns of the uterus the entire Ova, with their beautiful annular placentÆ, while the foetus in each of them was still perfectly lively, and could distinctly be seen, through the membranes, to move, I found that at the end of thirty-five, forty, and even forty-two minutes, some of them were still alive, the Ova remaining entire all the time, and upon the table^[10].

60. When the Ovulum has made good its fastening to the adventitious lining of the womb (decidua), the circulation of the blood in it is as yet imperfect. The Ovulum does not—cannot—receive the blood of the mother. How could such a gossamer-like being, organized as the Ovulum has been proved to be, during the first days after fecundation, be made a part of so impetuous a torrent as the circulation of the blood of the mother, without instant destruction to the produce of conception? No. The blood of the embryo is first formed within itself. (Prevost, Home, Magendie, Adelon, Serres, Rolando.)

61. The newly-engendered being passes through two striking metamorphoses previously to the enjoyment of its extra-uterine life. These are the Embryonic and the Foetal states. The latter succeeds immediately to the former; beginning at the moment when the new being is grafted on the maternal womb, and continuing until its expulsion from thence at the full period of gestation. It follows, therefore, that the Embryonic or former state is that in which the new being is as yet, without any direct or indirect communication with the mother, and still less so with external objects. This state persists for about two weeks after fecundation, during which the Embryo continues to derive its nourishment from the cortical membrane of the Ovum. (Boer, Soemmering, Plagge, myself.)

62. The growth and progress of the Embryo or Foetus follow a very irregular march. Up to the second month the increase is somewhat slow—it is accelerated during the third—it slackens again at the fourth and fifth months—between which and the last month the increase is more rapid, until it has acquired its proper maturity. (Autenrieth, Soemmering.)^[11]

63. The Embryo may be perceived, with the naked eye, at the fourteenth day after conception. It measures then 1–12th of an inch in length. (Dr. Pockels.) On the third week, it is 1–10th of an inch long. It is as large as a house-fly at four weeks, and as a horse-fly at six weeks. At two months it weighs twenty grains, and is one inch long. It weighs an ounce and a half at three months, and measures three inches; between which time and the sixth month it increases in dimensions from three to nine inches, and in weight from one ounce and a half to one pound. The relative weights of augmentation of length for the seventh, eighth, and ninth months stand thus:—from two to four pounds, and twelve inches; from four to five pounds, and seventeen inches: from five to eight pounds and twenty-two inches. (Averages of minute and accurate observations made by Autenrieth, Soemmering, Bichat, Pockels, Carus, &c.—confirmed by my own observations made on several early ova, and many foetuses examined in the course of seventeen years obstetrical practice.)

64. Towards the end of the first month it is easy to distinguish the head of the foetus, which has the appearance of a vesicle composed of thin membranes, and is as large as the rest of the body. The latter is straight—and there is in one part of the head a black dot, marking the spot for the eyes. (Plate I. fig. 5.)^[12] But it is during the second month that the various parts of the face, as well as the superior and inferior extremities, become visibly delineated in the foetus. The eyes are indicated by two black spots of considerable size, compared to the volume of the foetus. The eyelids are not spread over them until the tenth week, at which time the external concha of the ear, as well as the profile form of the nose, become properly defined. At this same period we find the mouth, which was at first a simple opening of no mean size, becoming more distinctly delineated, owing to the formation of the lips. These soon approach each other, leaving a simple transversal slit or depression between them. (Plate II. fig. 11 and 12.)

65. The extremities appear in the form of globular tubercles at first; the superior preceding the inferior by a short period of time. Until between the third and fourth month, the lower are smaller than the superior extremities. Even at the latter month they are shorter than the projection of the os coccygis. The parts of reproduction may then be distinctly seen. In the male as well as in the female, these parts are exceedingly prominent. (Plate V. fig. 18 and 19.) But the difference of the sexes may be deduced from other circumstances besides the sexual organs. Such as the particular structure of the thorax and abdomen, the form of the head, the extremities, and the dorsal spine. (Autenrieth, Soemmering, Meckel, Velpeau.)

66. The external organs of the foetus are all well defined at the end of the fourth month. The abdomen is fully covered in; the intestines are no longer visible. By the sixth month the foetus is perfect in its shape and formation. In the seventh, eighth, and ninth months, its successive development is limited to mere size, volume, or amplitude, and a proportionate increase in weight. It is well to keep in mind, that although the growth of the various parts of the foetus bears a proportion to the general development of its body, that part of the body which is above the navel, measures in length more than the part below it, until the full and complete period of gestation, when the navel marks the precise middle of the length of the foetus. This circumstance assists us materially in forming our opinion respecting the age of any foetus, either as a matter of curiosity, or as a guide in questions of forensic medicine. (FoderÉ, Chaussier.)

67. It was supposed, until within the last fifteen years, that the nervous system was the first to be formed in the human embryo; but recent discoveries have proved that the vascular system has precedence of the former. The nerves invariably appear after the arteries which they are intended to accompany. The spinal marrow appears before the brain, and the latter before the cerebellum, and accordingly it is found that the arteries of the spinal marrow shew themselves before those of the brain, and the arteries of the brain become manifest before those of the cerebellum. In this respect the organogenesy of the human foetus is analogous to that of birds. (Serres, Desmoulins, Adelon.)^[13]

68. The blood is formed independently of the heart, and appears at two distinct points from it, and acquires a motion independently of it. (Prevost, Dumas, Baer.) The veins are formed first—next, the heart—lastly, the arteries, &c. (French Physiologists.) The arteries are, by an Italian physiologist, said to be the first to appear. (Rolando.)^[14]

69. The nervous system is not developed, beginning at the centre and proceeding towards the circumference of the embryo, but the reverse. Thus the lateral nerves of the head, trunk, and pelvis, are already formed, when the cerebro-spinal system is yet in a liquid state. It follows hence that those nerves cannot be considered (as it has all along been supposed) in the light of emanations from, but as distinct bodies proceeding to, that particular portion of the nervous system. (Serres.)

70. Of the apparatus for digestion, the intestinal canal is the first to appear. It consists, during the first days of its formation, of an open gutter, extending the whole length of the embryo, placed before the vertebral column, and gently curved like a canoe. It is in communication with the vesicula umbilicalis, or intestinal vesicle. (Wolf, Meckel, Oken, Baer.) The gutter, without losing altogether its communication with that vesicle or chamber during the first ten or twelve weeks, becomes closed at last, and extends, lengthens, and expands in a variety of ways. One of its extremities, the mouth, appears between the fourth and fifth week. It is open on the sixth. The other extremity, the anus, opens on the seventh week. About the ninth week, the outlines of a stomach are visible. (Meckel., Adelon, Velpeau.)^[15]

71. The Vesicula Umbilicalis (intestinal vesicle) corresponds to the vitelline sac of birds. The discovery is due to Bojanus. In the human embryo it measures about half an inch in diameter. It is situated immediately against the anterior surface of the embryo (Lobstein); but it gets further from it at the end of the first month, when it is found on the outside of the sheath of the cord. (Meckel.) It is composed of a granular membrane of considerable tenacity. It contains a whitish liquid, which gradually diminishes—becomes thicker, and ultimately, hardened; while the vesicle itself withers, and becomes opaque. It receives the blood vessels called omphalo-mesenteric. (Pockels.) It disappears generally about the third month. (Meckel.) It has been observed, though extremely rarely, at the full period of gestation—placed at a short distance from the insertion of the cord into the placenta, but not larger than when seen at between two and three months. (Hunter, Meckel.) It is connected, as stated before, by a short neck, and by vessels, with the smaller intestines at the termination of the ileum (Meckel)—or at the cÆcum, which is, in reality, the representative of the vesicula vitellaria drawn into the abdomen as in birds. (Oken.)

72. At the lower end of the anal intestines, there projects another vesicle or sac, to which the name of Allantoid has been given. It exists in birds—in all the mammalia—and in the human embryo. In the latter it appears about the fourth week, and by the sixth week it has almost disappeared. Its existence is therefore but short, while the size it attains is always trifling. Not so with the mammalia, in which it acquires great amplitude. The communication of this sac with the bladder, by a canal called the urachus, and which canal is found impervious after the first three or four months of gestation, is admitted by all observers. (Meckel, Baer, Dutrochet.)

73. The umbilical cord or navel string, in man, has been found to spring from a vesicle to which the discoverer has given the name of Erythroid. (Dr. Pockels.) This vesicle had been before observed in the mammalia. (Oken.) The cord appears at the end of the third week. (Pockels.) It then consists of a vein and two arteries, the urachus, a species of gelatine of a ropy nature, called the gelatine of Wharton, a portion of the intestinal canal, (larger in proportion as the embryo is younger,) the vesicula umbilicalis, in part, and the omphalo-mesenteric vessels, the whole enveloped by a sheath proceeding from the involucra of the ovum already described. The last three constituent elements of the cord, however, become obliterated or disappear after the third or fourth month of gestation—the others remain permanent throughout that period.

74. The umbilical vein and the arteries are spirally twisted together and in the majority of cases they are so from left to right. (Hunter.) The former contrivance is evidently intended for the purpose of giving the greatest possible extension of tubular passage for the blood compatible with the smallest increase in the length of the cord. The cord which is very short at five or six weeks, becomes at the conclusion of gestation from one foot six to two feet long. (Chaussier.)

75. The umbilical arteries, two in number, are a continuation of the primitive iliac arteries; they pass over the lateral regions of the bladder, ascend along the internal surface of the anterior abdominal covering of the foetus, approaching each other as they get nearer to the navel, through which they emerge in order to enter the sheath of the cord, winding round the vein in their way to the placenta. (77) The vein on the contrary which proceeds from the placenta is of a larger calibre than that of the two arteries taken together. It is soft and extensible—and after having slightly meandered within the umbilical sheath penetrates through the navel into the abdomen of the foetus, directs its course towards the inferior surface of the liver, enters the antero-posterior fissure of that viscus, unites with the left branch of the hepatic and vena portarum, and reaches under the name of the venous duct, the inferior cava. It has no valves, except one at its intro-abdominal bifurcation. This vessel, throughout its course, becomes obliterated after birth.

76. The omphalo-mesenteric vessels consist of a vein and an artery, the ramifications of which, externally to the foetus, are seen distinctly on the umbilical vesicle (vesicula intestinalis). They accompany the cord as far as the navel through which they pass into the abdomen. They then separate, the former proceeding on the right to join the trunk or one of the branches of the mesenteric vein, and the latter on the left to join the superior mesenteric artery. These vessels are obliterated, as the vesicula umbilicalis to which they belong disappear, and lastly disappear in their turn. They have, however, been observed sometimes in the cord of the full grown foetus, like whitish solid filaments. (Chaussier, Beclard.) In the recent case of an individual twenty years of age, who died of consumption, these vessels were found as pervious as when existing in the embryonic state, and contained blood. (Spakenberg.)^[16]

77. When the Ovum is advanced to the second or third month of its fecundated existence (for the period varies in different examples I have had under my observation); its attachment to the Uterus, is firm and complete. Many of the vessels of the external surface of the chorion, which by this time have increased in size, while their free ends have luxuriantly branched out in innumerable minute vessels, have clustered together and formed what are in reality cotyledons—by means of which the said attachment is principally effected. (Personal observations and experiments.) The congeries of these clusters of vessels constitute the principal part of what has been called the Placenta, which grows in size and expands as the gravid uterus expands progressively during gestation.

78. The Cotyledons sometimes consist of only one short and very thick principal trunk—dividing itself, at a short distance from the surface whence it springs, into two, three, sometimes more, lesser trunks, and then again subdividing into thousands of smaller tubes;—at other times the cotyledons consist of two or three distinct straight trunks of different calibre springing from the chorion close to each other (as insulated clusters of lofty and straight trees are often seen here and there on a plain); in which case, the corresponding subdivisions being more numerous, the cotyledon is necessarily larger. (Personal observations, 1825, 1826.)

79. The main trunks of these cotyledons are ramifications of the umbilical vein and arteries, seen to spring from the subdivision of those vessels which are observed to run horizontally on the foetal surface of the placenta, and which are the termination of the umbilical cord. Between these cotyledons there are spaces of various sizes in which the surface of the Chorion is clear of all filaments, vessels, or any other attachment or projection whatever,—such surfaces are smooth and shining. (Personal experiments, 1825, 1826.)^[17]

80. The trunks of the cotyledons and their subdivisions whether springing from the vein or from the arteries of the cord have their coats made of the Chorion and amnion which accompany each cluster so as to form the thinnest pellicular receptacle for their ramifications. It follows hence, that when a coloured liquid, or even air is injected through the arteries of the cord, no escape of the injection takes place, nor can take place, from the terminal vessels of the clusters or cotyledons—and as it is found also that the same injection, if projected long enough (without lacerating any part of the gossamer-like structure we act upon) is brought back by the vein of the cord (which has no valves to prevent such a return) another conclusion is inevitable, namely that the terminal arterial vessels become, by a continuous arrangement, incipient radicles of the venous tubes. (Personal experiments, 1825, 1826.)

81. Now in as much as in the human placenta, expelled at the full period of gestation, before any experiment be undertaken to disturb its integrity, the lobes which it presents have each the appearance of a continuous mass, without any intervening spaces (79); and as these appear only clear, smooth, and shining, after maceration and much patient dissection that leaves nothing rough, or lacerated or divided by violence, behind; it follows that a something must have been removed, during the process of maceration and dissection, which before the employment of those processes occupied the spaces in question. (79.)

82. That something consists in a congeries of blood-vessels, arterial as well as venous, proceeding from the longitudinal vessels of the decidua covering the placenta (Dr. Hunter, Chaussier, Meckel, Lesauvages, myself). These vessels ramify in a manner analogous to that in which those of the foetus have been described to ramify, (78, 79.) They penetrate between the interstices left by the minutest branches of the umbilical cotyledons. Their direction is lateral, perpendicular, oblique, and variously tortuous, in reference to the plane of the decidua whence they originate. Wherever they form a thick cluster, they are found to occupy one of the spaces already described (79). To facilitate this arrangement, and to render the distribution of the decidual vessels throughout the masses of the umbilical cotyledons more effectual—the membrane itself (decidua) is found to dip among the latter, dividing the general mass into lobes of various sizes, by which contrivance the decidua acquires an additional extension. (Personal Observations and Experiments.)

83. The decidual vessels are formed by continuous arterio-venous tubes. They reach, but do not connect themselves with the chorion. In the same manner as the terminal vessels of the umbilical cotyledons reach, but do not connect themselves with the superimposed decidua. When an attempt is made to remove (peel off) the latter from the surface of the placental mass, we notice certain attachments between them which are torn in the removal. These are the decidual vessels (82) and not as stated incorrectly by some, the terminal vessels of the umbilical system. (Recent German, and French, and Personal Experiments.) In the same manner as the umbilical vessels are accompanied by the chorion, the decidual vessels are accompanied by a membrane peculiar to the placenta, which I have called the membrana propria.

84. If we take a placenta which has been expelled from the womb, in all its integrity, between the fifth and seventh month, when the vascularity of the decidua is considerable, and after carefully washing its surface in tepid water, we plunge it in a weak solution of alcohol, so as to harden the decidua in some degree, we shall be able to slice off the latter from the surface of the placenta, at the depth of about the tenth of an inch, without injuring the delicate texture of the membrane. This should then be carefully macerated by turning the under surface upwards, under water, when, after a time, much of the tomentous attachment seen floating, will gradually be detached, and leave part of a smooth surface behind. If the membrane be then viewed with a strong magnifying glass, on its upper surface several orifices, with regular edges, but of various aperture, will be observed, through which, if we introduce a slender pipe and blow air into them, not only the longitudinal vessels in the decidua will be seen to fill with that fluid; but the short fragments of their ramifications pendent from the under surface of the membrane, will be distended, and the air will pass through them bubbling up through the water, thus denouncing their own vascular nature and arrangement. This is an experimentum crucis. (Original, 1826–27).

85. The orifices in the decidua have been denied by one or two recent writers, particularly by Professor Lauth; but they are admitted by all the rest of the modern physiologists and anatomists, from Dr. Hunter down to the latest experimentalist on the subject. It is through these that the injection, thrown into the uterine vessels, while the placenta is still adhering to the uterus, passes into that part of the placental mass which is formed by the decidual ramifications. In a very beautiful and most accurately conducted experiment made at the Middlesex hospital, by Dr. H. Ley, (March, 1833,) the particulars of which, I hope, to see published by that able physician; a red injection was pushed, without any difficulty,—laceration,—or extravasation, towards the adherent placenta, from the uterine vessels of a pregnant woman, who died of a disease of the heart, undelivered; when it was found to have penetrated, in the most regular and uniform manner, to the very remotest terminal ramifications of the decidual vessels. The placenta was then carefully detached, the decidual surface was carefully examined with magnifying glasses, no laceration could be detected, except what had been made by accident or violence in a small part of its circumference while the placenta was being detached from the womb. Orifices, as distinct and as properly organized as orifices can be in membranous textures, were seen in many parts of it by more than one competent and unbiassed person; and air was blown through some of them, or a small silver pipe introduced, without effort or laceration. Not the slightest vestige of extravasation, or lump of injection, was observed in any part of the intact placenta when cut into. This same result has been obtained, it is understood, in a recent injection by Sir A. Cooper, but the nature of the experiment is not yet known. The same result was obtained by Dr. Hunter, whose positive affirmation has been so recently questioned. The same result has been obtained by Lobstein. The same result has been obtained by Chaussier. Such a result is believed to be correct by Magendie. Professor Mende, in a report to the Obstetrical Society of Gottingen, states having made the experiment of injecting the uterine vessels with air—and with milk, in the case of a woman who died (1830) after the CÆsarean operation, the placenta remaining firmly adherent to the uterus, and he obtained the like result—as Hunter and others. Can we, therefore, refuse credence to such a host of eminent men and experimenters?

86. The decidual vessels derive their fluid from the uterine vessels. The arteries which convey uterine blood to the decidual vessels, are tortuous and very small; they are the adventitious produce of the membrana propria of the womb acting under the influence of a peculiar stimulation which produces the decidual membrane, as inflamed surfaces produce organized exudations. Though the latter be formed in the uterus, even when the embryo is lodged, by aberration, in some other part of the abdomen, its presence must not be deemed, on that account, unessential to the embryo; for a vascular membrane, as nearly alike to it in texture as can be, has invariably been found to connect, by blood-vessels, the embryo to some vital part nearest to where that embryo has been casually deposited, that part having, at the same time, its circulation and vascularity greatly increased, and becoming, in fact, the parent of the connecting vascular membrane in question.

87. Nothing proves more distinctly, (it might be said, almost to demonstration,) the accuracy of the views (82, 83, 84, 85) which tend to establish the fact of a vascular communication between the arterio-venous system of the mother and the placenta (by intermediate decidual circulation) and to shew the fallacy of those who deny such a communication, than the very phenomenon just noticed (86). Here, morbid anatomy again comes to the assistance of normal anatomy and physiology, and affords evidence which is not liable to the errors that have been unjustly affixed to experimenters with injected fluids. Of the many examples that might be quoted in support of this proposition, the one which is stamped with the authority of Lallemand may be selected as the most striking^[18]. In a case of ventral aberrant foetation, which had proceeded to the end of the sixth month, before it destroyed the patient, a vascular and tomentous membrane had been formed on the surface of the peritoneum, to which adhered the regular placenta and chorion of the foetiferous ovum. This membrane resembled in every respect the decidua, at six months—it was thicker, and more red and vascular where the placenta was adherent than any where else. “Vessels as visible as those of the inflamed conjunctiva,” observes the author, “passed from the highly injected peritoneum, opposite the placenta, into the membrane which lay between them; while other vessels from the placenta reached as far as the same membrane, and were lost in it where they probably anastomosed by their very minute terminal ramifications.” (Lallemand). The conclusion which this really eminent physiologist and good man has come to, upon this subject, is striking, and truly to my purpose. “The decidua,” says he, “has no other function to perform than that of serving as a capillary system, intended to be the medium of communication between the blood-vessels of the mother and those of the foetus” (page 21).

88. It is possible that the venous blood of the decidual vessels may be returned through the great uterine sinuses, the large open orifices of which, covered with an almost valvular flap, have been described by the best anatomists, as being applied to the surface of the decidual placenta. Magendie^[19] thus states his opinion on this subject. “In women large openings, which communicate with the uterine veins, are observed on that part of the uterus to which the placenta adheres; but it is not clear whether these venous orifices are destined to absorb the blood of the foetus, or to suffer that of the mother to escape on the surface of the placenta. I am inclined to admit the latter idea—but no proof whatever exists of its correctness.” (page 554).

89. Such is the real structure of the human placenta (77 to 88, inclusive). Its description is founded on positive and direct experiments, first-rate authorities, and anatomical inquiries, which may be repeated, referred to, or ascertained any day, and to which many can bear witness: any other description differing from it and not so grounded, must be erroneous. This view of the real structure of the placenta differs from that of Dr. Hunter only in the non-adoption of that great man’s notion that continuous vessels go from the uterus, through the decidua, direct into appropriate cells or laminÆ, where he supposed that the arteries deposited their blood, which the veins pumped back into the uterine system of the mother, after it had served the purpose of bathing the terminal or cotyledonic vessels of the foetus. The existence of cells, however, has been frequently denied, and by none more stoutly than by Professor Lauth, of Strasburgh, and others; but as these individuals deny, at the same time, that which a hundred anatomists of great skill and veracity have seen, namely, the transmission of fluids, by means of decidual vessels, from the uterine system into the placenta, their opinion is liable to suspicion. However, it is unquestionably true, that on looking at the appearance exhibited by the fluid injected from the uterine vessels, in those portions of the placenta which it reaches, (Experiment at the Middlesex Hospital, 85,) we feel more inclined to consider it as dendritic and ramose, than extravasated or diffused. I entertain the former opinion. I submitted a thin section of the injected placenta (March, 1833) (85) to a powerful magnifying lens before a very strong flame of an argand burner, and could not perceive any sensible difference between the appearance of the red and that of the yellow injection. Now, that the latter, which was thrown in through the umbilical vessels, had been deposited within minute vessels, and not within cells, no one doubts. It is, therefore, likely that the other fluid is also so deposited. If Hunter and his followers were wrong in their conclusions, (though accurate in their experiments,) Professor Lauth, and the author of a paper on the placenta, inserted in the Philosophical Transactions for 1832, (who, by a most singular coincidence repeats all that Lauth had said long before him respecting the non-existence of cells and of continuous vessels from the uterus in the placenta) are not less chargeable with even greater errors; inasmuch as they have denied anatomical facts which have been observed and ascertained by many. They have overlooked the function of the decidual vessels, and they have said not a word of that beautiful arrangement of the foetal vessels of the placenta which Dr. Hunter compared to the “vascular portion of the chorion forming part of the placentulÆ in a calf,”^[20] and which I have succeeded in demonstrating in a human placenta prepared for that purpose, and still in my possession (79, note). It is evident that under such negative circumstances their view of the structure of the human placenta, and its connection with the uterus, will be repudiated.

90. The circulation of the blood in the Ovum is independent of that of the mother (personal experiment (59), and all the more recent physiologists). The embryo creates its own blood, and through it, sustains its own existence. But its blood, like that of all other animals, whether during its intro or extra-uterine life, requires to undergo certain changes at every minute period of that life—and those changes it experiences through the influence of the blood of the mother. (Magendie, Mende, Pockels, Baer, Chaussier).

91. The function of the Placenta, therefore, seems to be to facilitate, and in good truth to effect, the necessary changes in question (90). The decidual vessels receive the arterial blood of the mother. This is spread over a very considerable surface of tubular structure, which being, in its distribution, made to come in apposition with the infinite ramifications of the umbilical placental vessels, at innumerable points, (like the inspired air distributed through the bronchial passages is made to come in apposition with the myriads of vascular rami of the lungs); the required changes in the blood of the foetus are produced, just as the changes called for in the pulmonic blood, are produced by the peculiar arrangement of that part of the animal economy. When the arterial blood of the mother has produced the desired effect on that of the foetus—it is returned by the decidual veins to the uterine sinuses applied, like absorbing mouths, to the surface of the decidua, when it enters into the general venous system of the mother (Magendie; Personal Observations).

92. Of the two vascular systems, forming the machinery of the utero-decidual and foeto-placental circulation, (82 and 77,) that of the former is the smallest and least extensive (See injections in all the Museums). In point of origin, also, the latter has precedence. The Umbilical vessels unite the foetus to the chorion before any regular placenta is formed outside of the membrane. Up to the tenth week the decidual vessels are as yet slender, straight, and insulated; while the umbilical vessels begin already to arrange themselves into minute cotyledons^[21]. The reason of these arrangements is obvious. The embryo needs growth. This it gets through the maternal blood. But as its gossamer frame, for the space of two and three months, requires but little assistance from such a source for the promotion of growth; and as a large supply of maternal blood, at that early period, would overwhelm, instead of enlarging, the embryonic fabric, such an arrangement of means only obtains, in the reciprocal circulation, as is calculated to ensure the desired effect (Personal Observations).

93. This effect is nutrition. “Considering the power which the Ovulum displays when it first reaches the uterine cavity, of imbibing matter for its growth, together with the facility with which, according to Dutrochet, fluids may be drawn through animal membranes, it is not difficult to believe that nourishment is directly imbibed from the vessels of the mother by the circulating fluid of the embryo, through the fine intervening membranes.” (Mayo’s Outlines of Physiology, p. 437. 3d. Edit.)

94. It is possible, also, that other means may be at play in the promotion of such an effect (93) in the foetus, besides the one before mentioned (91). We may instance as a probable one, lymphatic absorption. The probable existence of lymphatics in the placenta was admitted by Dr. Hunter. “It is most probable that it (the foetus) is nourished by thousands of small lymphatic vessels which absorb nourishment from the blood of the mother and carry it along the navel-strings. It is true we cannot see any lymphatics running upon the navel-string, yet it is reasonable to conclude they do.”^[22] Hunter’s conjecture has since been realized (Chaussier, Fohman, Uttini, Lauth). The second of these anatomists has delineated them in rich profusion, extending from the placenta along the funis, leaving the funis at the navel, and directing their course to the groin (Mayo).

95. Some have ascribed the nutrition of the foetus to a regular deglutition and digestion of the amnionic fluid. Many facts render this opinion probable (Meckel). But there are also facts which would make nutrition by such a means impossible (Dr. Hunter). 1st. An embryo, at an early period, cannot be nourished by the mouth. 2dly. The amnionic fluid is mere water with a vestige only of albumen, the only nutritive quality in it. 3dly. A foetus was seen whose intestine, a little below the duodenum, was impervious and divided through, and the lower end began at some distance from the higher portion. (Dr. Hunter’s MS. Lect.) 4thly. A full grown child was brought into the world without head, heart, lungs or intestines (Dr. Cooper, in Dr. Hunter’s MS. Lect.) 5thly. A kitten was sent to the Royal Society, full grown, born without either nose or mouth. (Dr. Hunter, ibid.) 6thly. I have the drawing of a pig (the preparation of which I exhibited at the Med. Ch. Soc. in 1814,) which was born, at the proper period, and full grown, without any vestige of the under jaw, and consequently without either mouth or any passage into the stomach.

96. Some have thought that the amnionic fluid was absorbed through the pores of the skin (Osiander), others through the mammÆ of the foetus (Oken). That the vesicula intestinalis (umbilicalis) contributes to the growth of the embryo is a great deal more probable (Blumenbach, Soemmering, Lobstein, Joerg.) It is also not improbable that the gelatine of Wharton, contributes to that object (Lobstein). But these are all conjectures, for the probability or improbability of which as many arguments and real facts have been alleged on equally unquestionable authority. “Ce sujet,” observes Magendie, “a souvent exercÉ l’imagination des physiologistes, sans aucun profit rÉel pour la science.”

97. I am more inclined to believe in the existence of respiration in the foetus as an additional means of facilitating growth and entertaining inherent life (Geoffroy St. Hilaire, MÜller). The presence of air, analogous to atmospheric air, in the amnionic fluid, has been detected (Lassaigne). I once had in my possession an intact ovum at five months (30th June, 1826,) which served me for the purpose of studying more particularly the real structure of the placenta, and which contained, besides the amnionic fluid, a bubble of air about the size of a small plumb. Only a portion of this was, through the awkwardness of my assistant, received in a glass tube containing distilled water, while I punctured, under water, the membranes in the centre of the bubble. This portion was afterwards made to pass through a saturated solution of lime in water, and produced a visible cloudiness denoting the presence of carbonic acid. The respiration of the foetus is supposed to be effected by the cutaneous pores, as in aquatic insects (Geoffroy St. Hilaire). In addition to which the placenta is looked upon as performing the office of lungs (MÜller). Dr. Edwards’s experiments on the asphyxia of the Batraciens, may serve to throw light upon this question (Breschet).

98. The nature of the changes which the blood in the foetus may be supposed to undergo from arterial to venous, and the converse, has not been satisfactorily ascertained. The colour of the blood in the umbilical vein is something lighter than that in the umbilical arteries (Mayo). This alleged change is not admitted by others (Meckel). I have never been able to detect the least difference between the arterio-umbilical and venous-umbilical blood, in the many cases I have examined. But the absence of any change of colour does not necessarily imply the absence of any inherent change in the blood of the two systems. The globules of the foetal blood do not resemble those of the blood of the mother (Experiments alluded to by Dr. Breschet).

99. Connected with the subject of the nutrition of the foetus and the changes which take place in the blood of it, may be mentioned certain recent discoveries^[23], which would lead to the belief, that the function of the placenta is probably analogous to that of the liver during the intro-uterine life of the foetus, and that the presence of bile in the blood of the placenta, discovered by modern chemists, is necessary to the maintenance of foetal life (Breschet).

100. It is of the utmost importance to bear in mind the great distinction which exists between the independence of the foetus, quoad life, and its dependence, quoad nutrition, in respect to the mother. The former state is secured by a total separation of the two circulations (maternal and foetal). The latter by the close reciprocal contact of the organs of those circulations. Thence is it that we find the foetus to live on, notwithstanding that its connection with the mother has been partially and sometimes even wholly, severed;—while on the other hand we cannot help admitting that, albeit this independence, the influence of the mother over the fabric of her offspring is unquestionable.

101. Here are two important positions. I have mentioned my experiments on the intact ova of the genus cat, (59,) to illustrate the first of them, and Dr. Prevost has since come to my assistance with as strong a case in further support of it^[24]. This gentleman having observed an ovum still alive in the uterus of a ewe, which was a short time advanced in gestation, removed it and placed it upon a warm glass plate exposed to the rays of the sun, and attentively examined it with the microscope. The beatings of the heart became more lively. He noticed the blood arise to the surface of the chorion from the foetus, there ramify plentifully, and by anastomosing vessels, return to two of the larger trunks which were the veins of the embryo. He concluded, therefore, that the ovum was an isolated substance.

102. In proof of the accuracy of the second position, we have equally strong evidence founded on experiments. Magendie introduced camphor into the veins of a pregnant bitch, and he found that the blood of the foetus had, at the expiration of a quarter of an hour, acquired distinctly the smell of that drug (Physiology, 2d Edit. 1825). Quadrupeds carrying young were made to take with their food four ounces of madder-root. The colouring matter of that substance was found to have passed from the mother to the foetus; as all the serum of the blood of the latter, the urine, the liquor amnii, the teeth and the bones were tinged with it (Dr. Mussy, 1829)^[25]. In 1827, I undertook, at the request of Sir E. Home, a set of experiments on the human subject, with a view to ascertain the truth of my second position. Six gravid patients of one of the lying-in institutions under my direction, who required the constant use of aperient medicines, were instructed, towards the close of their time of gestation, to take at night, for a period which averaged about a week, from ten to fifteen grains of rhubarb in powder. After two or three days the effect was visible in the colour and smell of the urine of the patients previous to their confinement, and in one of them, in the colour and smell of the transpiration also. During the labour care was taken to preserve part of the amnionic fluid in a cup, the umbilical vessels were suffered to bleed on the side of the child after their recision, and the blood set apart so as to separate the serum, which was obtained in small quantity only.—Lastly, the first urine of the child was collected in sufficient portions. Each of these secretions appeared distinctly tinged by the yellow root, and bore the smell of it. When carbonate of magnesia was mixed with the fluids their colour became lateritious, and a reddish sediment was thrown down, evincing the presence of the drug which the mother had ingested. (MS. notes.)