This examination was made within less than twenty-four hours after the demise of the lady.

During the epidemic of cholera here, in 1832, I examined a gravid womb at term within a very few hours after the death of the woman, in company with the late Dr. J. Hopkinson, then prosector at the University of Pennsylvania. He, though a practical anatomist, was unable, as I was, to detect anything broken, save mucous tractus, though the light and the glasses were good, and the most scrupulous care was used, without precipitation or rudeness in the operation.

A similar opportunity was enjoyed, a few years since, at the Pennsylvania Hospital, in a womb gravid with twins. Here, also, I detected nothing but mucous tractus. Another very fine specimen, at the seventh month, was afforded to me by Professor Pancoast at the Jefferson College. In this case, many medical students observed the divulsion of the surfaces without detecting any vessels. I have had other similar opportunities, and obtained the same results.

On Friday, Dec. 15th, 1855, I examined the dead body of Mrs. late a patient of Dr. Weevil, in presence of that gentleman, Dr. Condie, and Dr. E. Wilson. She died of phthisis near her term. In the act of detaching the placenta from the womb-surface, we all with entire unanimity declared that we could not perceive that any vascular tract was broken asunder by the gentle, very slow, and most carefully observed process of disruption or separation of the two surfaces, uterine or placental.

I had a similar opportunity lately at the Blockley Hospital, when many physicians agreed with me in declaring that no vessel was seen in separating the placenta from the womb.

These are the opinions I adopt; but when so many explanations abound, who is he that can feel perfectly assured of the soundness of his own? There is one argument against these opinions which I conceive it a duty to state; for that which I desire is, the truth. The argument may be presented as follows:

It is admitted that blood vessels, whether arteries or veins, or capillaries, when deeply inserted within the tissue of an organ or viscus, always leave their additional coats and go within the intimate tissue. solely as membrana vasorum communis. Professor Burdach calls this lining membrane ENDANGIUM, a word more easily pronounced than the common Latin term, or the long English compound word liningmembrane of blood vessels. I greatly prefer, therefore, to employ the word Endangium, after the illustrious German teacher. Raciborski, also, in his elegant treatise on the veins, published in the Transactions of the Royal Academy of Sciences, clearly shows that the true blood vessel is

in fact this very membrane, and that the other textures found in larger arteries and veins are merely the protectors of the real vessel in its transit from the heart to the distal point in which its essential offices are to be performed. On various occasions I have been struck with this appearance in the large sinuses of the womb, some of which are so capacious as to admit the introduction of a finger into them. Here, the lining membrane, endangium, or true blood vessel rests upon the very substance of the womb, having no fibrous or other coating interposed between it and its proper basement texture, the uterus itself. The strong fibrous coats of blood vessels are never formed until after the essential endangium has for some length of time conveyed the moving blood along its channels. No one will deny this who has observed, with a microscope, the circulation of the embryo chick on the second day of incubation. Strong additional coats are gradually formed, and only in proportion as they may be requisite to resist the injection force of the heart.

It should be remembered that the womb is subject to great changes of condition. In the virgin, it is 2 inches in length, and weighs about two ounces. At term, it is 12 inches long, and weighs as much as two pounds. After delivery, it makes haste, by involution, to return to its pristine weight of two ounces, which it would be impossible for it to do provided its great blood vessels should have been strengthened with fibrous or elastic coverings instead of consisting, as they do, solely of the endangium.

As the womb grows, in pregnancy, many of its venous trunks become extremely large, and as they run in every direction in the wombstructure, some of them come so near the inner surface as to leave small spaces where the outer aspect of the endangium is destitute of any uterine basement. These thin or vacant spaces are chiefly seen on the part of the womb that is covered by the placenta, and are described by Dr. Lee as a sort of valvular apertures, representations of which he has given in an excellent plate in his Midwifery. The blood of the uterine veins would here press so strongly on the unsustained membrana communis as to rupture it were it not supported by the placenta, which acts as a cover or stopper, for the foramen, the removal of which would be sure to be followed by a rush of the blood.

During the process of its development, the placenta, which at first is a half-diffluent, softish mass on the exterior of the chorion, becomes continually of a firmer consistence. While it is in this half-plastic state, the blood driven along in the uterine veins moves with a force. sufficient to cause the delicate endangium across the above-named vacant spaces to yield in form of a pouch or cul-de-sac, that impresses,

indents, and sinks more or less deep into the softish mass of the placenta. These pouches or culs-de-sac are not properly vessels, but rather they are a sort of varicose state of the endangium, which contain the blood of the mother, yet keep it from all direct contact or mingling with that of the foetus.

It is my belief that these culs-de-sac or varices of the womb-veins are the vessels which Mr. Hunter describes as curling arteries of the womb. In many and patient searches for them, I could never discover one single tube that could be called a curling artery, as Hunter denominates them, and I cannot believe they do exist as a normal condition of pregnancy. As to the idea of Hunter, strongly advocated still by eminent English writers, that the blood of the mother is poured into what they call the cells of the placenta, I am unable to comprehend how it is that very learned people do still adopt it, for if there are cells or vacuoles in the placenta, which I deny, any blood that might fill them can be none other than extravasated blood, and yet the gentlemen insist that this extravasated blood can and does return again into the sanguine circulation of the mother! It is as easy to suppose that blood taken into a basin in venesection should again enter the torrent of the circulation, or that the extravasated fluid of a thrombus or ecchymosis should find its way back again into the vascular system. If the mother's blood could be poured into the hypothetical cells or vacuoles of the placenta, it would die by coagulation, for coagulation, which must ensue, is the death of the blood.

The blastoderm or germinal membrane is probably a progressive stage of the original maculæ germinativæ, or primary solid, and is stated to consist of three layers, which are the outer or serous layer, the inner or mucous layer, and the middle or vascular layer, for accounts of which I refer the Student to Rudolph Wagner's or Müller's Physiology. I shall not pretend to say that I know of a truth that the vascular layer gives rise to the sanguiferous system, the mucous layer to the digestive, and the serous one to the dermal and muscular system, ideas which, however well founded in anatomical truth they may be, seem at least to be altogether fanciful and hypothetical. Nevertheless, as there must be a germ-point, I have no objection to consider the macula as the blastoderm, and as the analogue of the cicatricula in the birds' eggs.

After the absorption of the ovarian ovule by a Fallopian tube, and its fecundation there, it increases rapidly in size, the segmentation of the yelk proceeds, and the fecundated egg moves slowly towards the womb, which it enters from the tube within some five or ten days. Being detained in the cavity by falling in some deep sulcus among

the convoluted mass of the swollen mucous tissue, it is there at last affixed, mesenterically attached, or conceived, for conception is synonymous with the permanent affixation of the germ.

It is presumable that the vitellary membrane which was originally what we called zona pellucida, now becomes transformed into chorion in part, and partly into the coating of the umbilical vesicle. The chorion is soon after this observed to be quite covered or clothed with innumerable villi or tufts, a kind of club-shaped conical or cylindric masses of cells that shoot out from the exterior surface and plunge their extremities like so many rootlets or pollen tubes into the orifices of the tubular glands, or wherever they may chance to find a resting place or materials for their endosmotic absorption. It is probably by means of these spongioles that materials for the nutrition of the ovulum enter within it; a view that derives some confirmation from the fact that the spongioles or tufts of the chorion disappear as soon as the placenta has acquired a sufficient degree of branchial and absorptive power.

The developing ovule is very soon covered completely up by the deciduous, or rather the muco-tubular mass in which it has fixed itself. The living point of womb surface to which it is affixed, now represents the utero-placental surface, for the placenta, growing from the exterior of the chorion, sits only there, but the ovule, hourly swelling or growing, pushes before it its covering that consists of the reflexed decidua or muco-tubular membrane which has invested the unattached portion of the ball like a cap or hood. Upon attaining a certain size in the course of the third month, this hood-like covering or reflexed decidua has become so much expanded and so thinned, as to give way before the enlarging ovum, which comes through the rent or hila and then applies its chorion directly to the muco-tubular membrane, or decidua vera which lines the whole interior of the womb. As the ovum grows onwards through the rent it has made in the reflex decidua, that body retires or shrinks back towards the placental disk and becomes a sort of ridge or cushion which we often find all round the placental margin.

The before formless mass within the ovum now begins to assume specific form and properties, by the evolution of a nervous and sanguiferous system; for, as has before been stated, the heart, originally a pulsating cylinder that thrust forwards a droplet of red blood, which ebbed back again as often as it was driven forwards, now begins to take on the proper forms and to be able to drive the red drop further and further into the softish, plastic mass until the track of the aorta is established. This aorta, after dividing itself as

was shown into two umbilical arteries, and completely setting up the omphalo-mesenteric system of circulation, rises, as we said, on the sides of the allantois to the inner wall of the chorion, which it pierces like a cribriform plate to go on the outer surface and there spread itself out in the shape of innumerable capillaries, arterioles and venules, whose tufted extremities apply themselves to the living wall of the womb. It is from that living surface that the placental vascular tufts draw the liquor sanguinis which the great umbilical vein next pours into the torrent of the foetal circulation, where it is developed and converted into red blood through the force inducted by the endangium. Thus only can the blood vessels be made; they are made by the blood itself which traces their paths, as it is injected by the heart into the soft and plastic sarcode mass. When once made, they ever afterwards restrain the blood, confine it within their own boundaries, and maintain its vitality by transmitting to it the forces of the nervous system of which they are the sole agents or machinery for this particular end; so that the blood, which created the vessels, becomes dependent on them for its whole subsequent life and powers.

The omphalo-mesenteric system appears to be designed as a means of maintaining the vitality of the yelk for a considerable period, indeed until the placental circulation being fully established there is no further use for it in the embryonal economy, after which it is laid aside and wholly disappears before the fourth month.

This omphalo-mesenteric apparatus does not, however, wholly perish, but loses only that portion of the vascular system that was spread on the umbilical vesicle. The artery, which is a mesenteric artery, and the vein, which is a mesenteric vein, is in fact the foundation of the whole portal system, on which depends the liver. The liver is supplied with blood from the portal vein and the hepatic artery, so that its great secerning office, so indispensable to the life of the creature, may with truth be said to spring in its origin from the omphalo-mesenteric circulation.

The Allantois is a sac or bladder that rises up from the pelvic or caudal extremity of the embryo, carrying on its sides the growing umbilical branches of the aorta. At first it is globular or oval in shape, because the abdominal walls of the embryo are still unclosed. But as these abdominal walls gradually lessen the aperture through which juts out the umbilical vesicle and the allantois, they all become confined in a narrowing opening which at last proves to be the navel. In fine, as the navel string attains its proper dimensions, they are inclosed within it in common with the omphalo-mesenteric vessels, so