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the pupil becomes visible. The kidneys, which at first were composed of numerous glandular lobules (seventeen or eighteen in number,) now unite and form a separate viscus on each side of the spine; sometimes they unite into one large mass, an intermediate portion extending across the spine, forming the horse-shoe kidney.

Lastly, the testes, which at first were placed on each of the lumbar vertebræ, near the origin of the spermatic vessels, now descend along the iliac vessels towards the inguinal rings, directed by a cellular cord, which Hunter has called Gubernaculum testis: they then pass through the openings, carrying before them that portion of the peritoneum which is to form their tunica vaginalis.

The length of a full-grown fœtus is generally about eighteen or nineteen inches; its weight between six and seven pounds. The different parts are well developed and rounded; the body is generally covered with the vernix caseosa;* the nails are horny, and project beyond the tips of the fingers, which is not the case with the toes; the head has attained its proper size and hardness; the ears have the firmness of cartilage; the scrotum is rugous, not peculiarly red, and usually containing the testes. In female children the nymphæ are generally covered entirely by the labia, the breasts project, and in both sexes frequently contain a milky fluid. As soon as a child is born, which has been carried the full time, it usually cries loudly, opens its eyes, and moves its arms and legs briskly; it soon passes urine and fæces, and greedily takes the nipple. (Naegelé's Hebammenbuch.)

Thus, then, in the space of forty weeks, or ten lunar months, from an inappreciable point, the fœtus attains a medium length of about eighteen or nineteen inches, and a medium weight of between six and seven pounds. As these observations on the development of the ovum show that the structural arrangement of the embryo undergoes a succession of changes, by which it gradually rises from the lowest to the highest scale of formation, so we shall find it furnished with a succession of means for its nutrition, each corresponding more or less to the particular grade of development which it may have attained. Its earliest source of nourishment is doubtless the vitellus, or albuminous contents of the vesicula umbilicalis. The radicle or primitive trace, in this respect, bears a strong analogy to the seed of a plant; it brings with it its own supply of nourishment for its first stage of growth; in the latter, the cotyledons afford nourishment to the little plumula, until, by the formation of roots and absorption of moisture from the surrounding soil, it is enabled to support the early rudiment of the future plant. The early function of the chorion is very analogous to that of roots; it is an absorbing apparatus, collecting nourishment by means of its numerous absorbing fibrilla: hence, according to Lobstein, the umbilical vein exists for some time previous to the umbilical arteries,

*The vernix caseosa is a viscid fatty matter of a yellowish white colour, adhering to different parts of the child's body, and in some cases in such quantity as to cover the whole surface; it seems to be a substance intermediate between fibrine and fat, having a considerable resemblance to spermaceti. From the known activity of the sebaceous glands in the fœtal state, and from this smegma being found in the greatest quantity about the head, arm-pits, and groins, where these glands are most abundant, there is every reason to consider it as the secretion of the sebaceous glands of the skin during the latter months of pregnancy.

and seems to perform an office in the fœtus similar to that of the thoracic duct at a later period; its radicles or absorbing extremities seem to absorb a milky fluid, which after the first two months is found in the placenta, and which must be looked upon as a means of nourishment which does not exist in the latter months. This milky fluid was noticed by Leroux, who even then expressed his doubts, whether the radicles of the umbilical vein receive blood from the mother, or whether they only serve to absorb a white fluid which resembles chyle. In some manuscript notes of Dr. Young's lectures, which were taken by the late Dr. Parry, of Bath, when a student at Edinburgh, we find the following observation: "There is evidently in the placenta, besides blood-vessels, some other substance, which serves to absorb juices from the uterus, and to convert these into a chylous matter, proper to nourish the foetus, and this matter is absorbed by the umbilical veins. This seems to be proved from the consideration of the placenta of animals which have cotyledons; for, on squeezing these glandular substances, we force out a sort of chylous liquor, and these are surrounded by the placenta, which absorb their liquor and convey it to the fœtus."

The absorbing power of the umbilical vein continues till the fifth month; during the second or third, the fœtus receives a good deal of nourishment from the liquor amnii, which at this period contains a considerable quantity of albuminous matter; this diminishes in the latter months of pregnancy. Moreover the body of the foetus begins to be covered with the vernix caseosa towards the seventh month, so that in the eighth and ninth months the absorption of liquor amnii by the skin is considerably impeded.

How far the full-formed placenta, as seen after the fifth month, serves as a means of nutrition to the fœtus, may still be a matter of doubt; its chief use after this period is, as we have already shown, for the purpose of producing certain changes in the blood of the fœtus analogous to those of respiration; still, however, it would seem that its function of nutrition. is not entirely at an end, even at a late period of pregnancy. The numerous little granules of phosphate of lime, which are frequently found on the uterine surface of a full-grown placenta at a time when ossification is. rapidly advancing in the foetal skeleton, would surely lead us to infer that the placenta in some way or other supplies the materials for this process.

Fætal circulation. We have already shown, that, in the early stages of development, the heart of the embryo is single, consisting of one auricle and one ventricle; that a septum gradually divides these into two parts until the double heart is formed, leaving two openings of communication between the right and left sides, the one between the auricles called the foramen ovale, the other between the pulmonary artery and aorta, viz. the ductus arteriosus.

From these and other peculiarities it will be seen that the foetal circulation differs essentially from that of a child after birth; and, in order to comprehend the nature and mechanism of the changes which take

*Foureroy, it is true, has shown that the fatal blood is not only of a darker colour, but incapable of becoming reddened by the contact of atmospheric air, and that it coagulates very imperfectly. Others have shown that there is no perceptible difference in the colour of the blood of the umbilical arteries from that of the umbilical vein. Still, however, this by no means disproves what we have now stated, and which is now generally allowed to be the office of the placenta during the latter periods of pregnancy.

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place in it when respiration first commences, it will be necessary that these peculiarities should be thoroughly understood. The condition of the fœtus must also be remembered: surrounded by the liquor amnii, the fœtus does not respire; its lungs have as yet been unemployed; they are therefore small and collapsed, and present a firm solid mass, nearly resembling liver in appearance. In this state but little blood from the pulmonary arteries can circulate through them; for, as the extreme ramifications of these vessels are distributed upon the mucous membrane lining the bronchi and air-cells, the free passage of blood through them will in great measure depend upon a previous condition of the air-cells. The pulmonary arteries in the foetal state are therefore small, and transmit but a small quantity of blood into their numerous ramifications, just sufficient to keep pervious these vessels, which after birth are to be so greatly distended in this state the lungs when thrown into water sink.


Hence, as the pulmonary arteries do not afford a sufficiently free exit to the contents of the right side of the foetal heart, nature has provided it with a peculiar means for carrying off the overplus quantity of blood, which is poured into the right auricle from the vena cava. This is attained first by the foramen ovale, an oval-shaped opening in the septum between the right and left auricles, and furnished with a semilunar valvular flap, so constructed as to allow a free passage for the blood from the right to the left auricle, but none in the contrary direction. By this means a considerable quantity of blood is transmitted at once from the right to the left auricle, and, consequently, much less into the right ventricle and pulmonary artery. Still, however, more blood passes into the right ventricle than the pulmonary artery, in the collapsed state of the foetal lungs, is capable of conveying away. The pulmonary artery is therefore continued beyond its bifurcation into the aorta at its curvature, by means of the ductus arteriosus, which, in the full-grown fœtus, forms a short thick passage between these two vessels; and in this manner is the right ventricle enabled to get rid of its surplus quantity of blood. Thus we see that the foetal heart, although consisting of two auricles and two ventricles, continues to perform the functions only of a single heart, both ventricles assisting simultaneously to propel the same column of blood, viz. that of the aorta, and thus enabling the heart to act with considerable power.

The chief part of the blood, which flows through the iliac arteries, instead of being sent to the inferior extremities, is carried into the umbilical arteries, which passing up along the sides of the bladder meet the umbilical vein at the navel, and thus form the vessels of the umbilical cord. These arteries convey the blood of the foetus to the placenta, where, having undergone changes to which we have already alluded, it is returned by the umbilical vein. This vessel, which afterwards forms the round ligament of the liver, passes through the umbilicus along the anterior edge of the suspensory ligament; it supplies the left lobe with blood, and having given off a communicating branch to the vena portæ, which supplies the right lobe, it passes at once by a short passage, called canalis venosus, into the vena cava.

Thus, then, the peculiarities of the foetal circulation may be considered as four, viz. the foramen ovale, or passage from the right to the left auricle; the ductus arteriosus, or communication from the bifurcation of

The pulmonary artery into the arch of the aorta; the umbilical arteries arising from the iliac arteries, and carrying the blood along the cord into the placenta; and, lastly, the canalis venosus, or passage between the umbilical vein and vena cava.

Let us now examine the changes which take place in the foetal circulation at the moment of the child's birth. The child, which had hitherto been immersed in the bland and warm medium of the liquor amnii, is at once exposed to the action of the external air. By means of the sympathy existing between the skin and respiratory muscles, sudden and convulsive efforts at inspiration take place; the air-cells of the lungs become partially inflated, and, after a short time, as the respiration increases in power and activity, become distended throughout their whole extent. The thorax rises; the flaccid diaphragm, which hitherto had been pushed up by the large foetal liver, now contracts, pressing down the liver into its natural situation. The lungs, from being a hard solid heavy substance, resembling liver, at once become inflated, elastic, and crepitous, light and permeable to air in every part.

The capillary terminations of the pulmonary artery, which ramify in the mucous membrane, forming the parietes of the air-cells, and which hitherto had been firmly compressed by the collapsed state of the fœtal lungs, are suddenly rendered pervious throughout their whole extent. By this means, a vacuum, as it were, is formed in the ramifications of the pulmonary artery; each inspiration is accompanied by a rush of blood from the right ventricle into the newly inflated structure. The pulmonary artery, at its bifurcation, swells, and becomes turgid: the blood is carried off into its numerous ramifications as fast as the right ventricle can supply it; this may be easily understood from the law, in anatomy, viz. that the area of two arteries is greater than that of the trunk from which they bifurcate. From this state of distention, the distance between the pulmonary artery and the aorta is increased; the ductus arteriosus, which has now become empty, is stretched, and thus partially closed; the right auricle, which, but for the foramen ovale, could not have cleared itself of the whole quantity of blood which was poured into it from the vena cava, is now enabled to transmit its entire contents into the right ventricle; the left auricle, which before birth was supplied only by the foramen ovale from the right auricle, is now rapidly filled by the blood brought into it by the four pulmonary veins;-the equilibrium between the two auricles becomes altered; the right, which hitherto had been somewhat gorged with blood, is now able to clear itself with facility; whereas, the left, which was but partially supplied, is now distended with a much greater quantity: there is now rather a disposition for the blood to regurgitate from the left to the right auricle; this, however, is prevented by the semilunar fold of the foramen ovale, which now acts as a valve, and generally becomes firmly attached to the septum. The obliteration of the canalis venosus at the posterior margin of the liver, and of the umbilical vein at the anterior edge, may, we think, be explained by the changes which necessarily follow the inflation of the lungs: the diaphragm, when it contracts, pulls down the liver into its natural situation; the distance, therefore, between the liver and the heart is increased, and the canalis venosus is.consequently stretched, and considerably pressed upon, and precisely the same results follow with the umbilical vein.









THERE is, perhaps, no subject connected with midwifery, which is of such importance, or which, from its difficulty and the serious questions it involves, demands such attentive consideration, and requires so familiar an acquaintance with every part of it, as the diagnosis of pregnancy. The responsibility which a medical man incurs in deciding cases of doubtful pregnancy, and in thus giving an opinion which may not only affect the fortune, happiness, character, but even life itself of the individual concerned, is rendered more painful by the perplexing obscurity of the circumstances under which these cases sometimes occur, being not unfrequently complicated with diseases which add still farther to the difficulty of coming at the truth, and occasionally rendered peculiarly obscure by wilful and determined falsehood and duplicity.

To render this subject more intelligible to our readers, we propose first to consider the general effects which pregnancy produces upon the system, and then to describe those changes and phenomena which are peculiar to this state, and which may therefore be taken as so many means of diagnosis.

Under all circumstances, the diagnosis of pregnancy must ever be difficult and obscure during the early months; the development of the uterus is still inconsiderable, and the effects which it may have produced upon the system, although appreciable and even distinct, are nevertheless too

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