as the womb grows larger in its progress, the umbilicus protrudes, because the ligamentous remainders of the umbilical vessels, which are deployed with the mass of the abdomen, can no longer draw it inwards. A pouting of the navel is, therefore, one of the consequences and signs of a pregnancy of six and more than six months' duration. Other tumors in the belly may make the navel to pout.

Cramps from Pregnancy.-Sometimes the gravid womb fills up by its bulk the cavity of the pelvis, so as to produce cramps in the legs by pressing too firmly upon and obstructing the sacral and obturator nerves. There is no remedy but patience and time.

Costiveness in Pregnancy.-When the womb has got fairly up into the cavity of the abdomen, it lies in front of the convolutions of the intestines; even the transverse colon lies rather behind the upper part of the fundus, so that when, in a gravid subject, the abdomen is laid open, nothing is to be seen but the uterus in front. The edge of the right lobe of the liver, or a segment of the greater curvature of the stomach, the omentum, and colon lie upon the top, and towards the reverse of the fundus uteri.

In this situation, it is impossible for the bowels to receive, in the same manner and degree, the stimulating and natural succussions of the abdominal muscles, as they receive them under ordinary circumstances. Those succussions are constant provocatives to a healthful activity of the peristaltic force, and are essential thereto. The failure of them tends to render the peristaltic motion languid or torpid, and therefore costiveness is a very ordinary state in advanced pregnancy. Let the Student reflect upon the evil effects of such torpor, in overloading the alimentary tube with the undischarged residuum of the digestions, by which the tension of the abdomen is increased, and the mesenteric and hepatic circulations and innervations brought into disorder, and which ought to be corrected by the proper remedies.

Alternate Hardening and Relaxation of the Womb.-As the womb approaches nearer to its term of gestation, the retentive faculty grows gradually less, from the deploying of the upper part of the cervix, which becomes a part of the general cavity for the accom modation of the ovum. The expulsive faculty makes frequent efforts to overcome the remaining antagonism of the cervix. These efforts, which doubtless lend a chief aid in the act of deploying the cervix uteri, are to be detected in the alternate hardening and softening of the globe of the uterus under one's hand placed upon the abdomen. If

the hand be placed upon the abdomen of a pregnant woman, it may be that the impression will first be received of a great softness and pliability of the textures, but, upon keeping the palm in situ, the tumor begins to grow harder and harder, until a very condensed condition of the organ is produced by this tonic contraction of its muscular tissue.

These contractions are not productive of the least pain or any disagreeable sensation, save a feeling which women designate as a "drawing" sensation. One feels surprised, sometimes, upon observing the very positive force of these contractions, to hear the woman say that they produce no pain in the back or hypogastrium; particularly as the same degree of hardening or contraction of the organ in a labor is accompanied with very decided pain. The reason of the difference is this-viz., the pains of labor are pains of the yielding but still resisting os and cervix; while these contractions, above described, do not cause any positive stretching and pain of either of those parts.

How the Cylindrical Neck becomes Conical.-These contractions are repeated very often during many weeks, and, indeed, it may be said they are reiterated throughout the whole duration of the pregnancy. The effect of them is gradually to reduce the cylindrical neck of the womb to the shape of a cone-or rather to the form of the lesser pole of an egg, and to make the os tincæ acquire a circular instead of its usual oblong or oval form, and to convert it into a dimple or pit in the apex of the now oviform uterus. When this dimple has become completely developed by the resolution of the cylindrical into the conoidal cervix, labor is ready to begin, and the next repetition of the contraction might justly be accounted as the first pain of the labor, for the labor pain is nothing else than contraction of the organ, by which the expulsive faculty strives to overcome the retentive faculty, and thus free the uterus of its contents, by thrusting them forth into the vagina, and thence into the world.

Size of the Gravid Womb at Term.-The uterus, rising upwards in the cavity of the belly, finally attains the length of full twelve inches. I measured the gravid uterus at term, in an individual who died suddenly before the onset of labor, during the month of June, 1848. It was twelve inches long, and eight inches in transverse diameter. The broad ligaments rise, of course, as the womb rises; and the ligamenta rotunda, which extend from the internal abdominal rings to the angles of the uterus, ought not, in a normal state, to be more than two and a half to three inches in length; yet by

the mounting upwards of the uterus towards the scrobiculus cordis, they acquire a length of five or six inches at least, serving to stay or steady the womb as it goes up, and, on occasions, to render it oblique to the right or left, in proportion as the right or left ligamentum rotundum is the readiest or the most reluctant to yield as the rising womb compels it to accompany the ascent. I call the attention of the Student to this condition of these ligaments, now, in order that he may in this connection clearly understand that, if the round liga. ments should not diminish their own longitude pari passû with the lessening of that of the womb after labor, and if they should continue elongated, or weak and relaxed, after the womb has returned nearly to its non-gravid dimensions, then the womb, having no support to prevent it from falling backwards, will be liable to dip its fundus below the promontorium, and be overset backwards, or retroverted. Whenever this accident happens, it is attributable to a fault of both the round and the utero-sacral ligaments; since, with round ligaments two and a half inches in length, the fundus could not pos sibly retreat far enough from the symphysis pubis to admit of the state of retroversion. Let the Student early learn that one of the common accidents of the lying-in state is this very accident, the noncontraction of the ligamenta uterina-and let him carefully estimate the effects, as to pelvic obstruction, pain, bearing down and general disturbance of the health, likely to arise from such an accident. While he is ignorant of these simple facts in pathology, he will permit his patients to suffer needlessly; but, well informed on this point, he will surely obviate by his precautions such sore distress. The accident is by no means an uncommon one after abortion at the third or fourth month. In such instances, and always, indeed, when the woman makes complaint of backache and pain within the pelvis, with tenesmus of the rectum or bladder, or both; and when she keeps her bed instead of getting up at the usual period and completely recovering as she might be expected to do a few days after the miscarriage, let the Student be careful to make a full exploration of the case. It is highly probable that all these complaints will be found to depend entirely on a retroverted state of the womb that has taken place because the ligaments could not contract soon enough and solidly enough to keep the organ in its proper position.

The Placenta.—A placenta is a vascular flesh excrescence from the exterior surface of the chorion, and is formed not before, but some time subsequently to the assumption by the embryo of its earliest form. Being produced solely by the chorion which belongs to the ovum, it has nothing to do with the womb except to attach itself to

it as a base on which it is to grow. At first it is probably a mere microscopic point situated upon a similar point in the uterus; it enlarges daily and exactly in the same ratio as the womb enlarges. It does not overgrow its base, nor does the base on which it rests overgrow it-they must augment at an equal rate.

In the primary stages of connection betwixt the ovum and the womb, the tufts of the chorion, which are merely masses of cells attached together as clubs or cylinders, do probably sink into the orifices of the tubular glands of the uterine mucous membrane, and derive from the secretions by their endosmotic power some cytoblastema that is appropriated to the earlier processes of development of the fecundated ovum. In the mean time, those curious acts called the segmentation of the yelk go on until the faint traces of the embryo come at last to be made manifest. The heart is a cylindrical tube that expands and contracts by turns, driving forwards into the soft and diffluent materials a drop of blood, which flows back again in the diastole. Little by little the quantity of blood increases, and is jetted further and further from the fountain of the circulation, making the track it is to follow, which gradually acquires the characteristics of a blood vessel. Each renewed jet drives the vessel further and further from the heart, and the omphalo-mesenteric vessels and the aorta are gradually formed. The aorta reaches the point of its bifurcation, and one branch becomes the right and the other one the left umbilical artery. These two vessels attached to the growing allantois extend with the expansion of that organ, and at length reach the inner wall of the chorion, through which they make their way, to be divided on the external wall of the same chorion into myriads of capillaries and venules and arterioles that convey the blood which is driven into their tubes by every systole of the embryonal heart. These blood vessels on the outer surface of the chorion lie in contact with the inner lining wall of the womb, carry their blood close along on its surface, and when they by the reunion of many capillaries have acquired the nature of veins, they serve as channels of return through which the placental blood is conveyed back into the body of the embryo.

Thus it appears that when the embryonic heart contracts it propels the blood through the aorta, the umbilical arteries, the placental capillaries and small veins into the great umbilical vein, and so, back into the heart from whence it was driven by the systole. In this circulation it has not at all mixed with the blood circulating in the vessels of the womb, nor has it acquired any blood, as such, from the parent. Yet it has absorbed, as it passed along her living surface, a portion of her oxygen. It has also imbibed by endosmosis portions

of plasma, or liquor sanguinis, which it is transporting to the interior of the embryo, in order that the said plasma may be by the power of the embryo or foetus converted into foetal blood. This plasma, or liquor sanguinis, is water containing dissolved albumen and salts that are susceptible of passing, by exosmose, out of the mother's vascular tubes, and by endosmose into the interior of the foetal vessels. It contains the elements of blood, to be elaborated within the economy of the embryo or foetus.

The Student now perceives that I would inculcate the opinion that the placenta only sits on the womb as a basis to rest on and as a living surface out of which to take oxygen and liquor sanguinis-that there is no inosculation of maternal with foetal blood vessels, and that the placenta is wholly and solely a product of the living ovum, with which the womb has no part nor lot, except to afford a point to rest on and a feeding ground from which to procure the alible materials of the

ovum.

The nature of the connection thus formed is the subject of great differences of opinion, that have not been settled even by the authority of John Hunter, who first proposed a rational explanation of this difficult point, in his article on the placenta, which may be consulted in his volume of papers on the Animal Economy. According to Mr. Hunter, the placenta is a symmetrical organ, consisting of two parts, one derived from the womb and the other from the child.

Seiler, in his work Die Gebaärmutter, und das Ei des Menschen, stoutly denies that the placenta belongs to the mother; and Velpeau, in his Ovologie ou Embryologie humaine, p. 65, says: "Et j'ose affirmer avec plus d'assurance que jamais que le placenta humain est entièrement foetal." I declare, with greater confidence than ever, that the human placenta is entirely fœtal.

While the celebrated Velpeau thus resolutely rejects the Hunterian doctrine that there is a uterine portion of the placenta, other very eminent persons equally insist that an important portion of the mass is actually derived from the womb; and that, whenever it is extruded by the contractions of the organ, not only is the foetal portion expelled, but the whole of the uterine portion also, which is detached at the same time, comes off with the foetal half; from which, indeed, there is afterwards no possibility of separating it, nor even of distinguishing them, the one from the other.

Prof. Owen, of London, is one of the distinguished naturalists who contend that the placenta is constituted of materials, part of which belong to the mother and part to the ovum. Mr. Owen says, after having carefully compared the Hunterian preparations with the results