Of the membranes we need not again speak, but merely to remark that the ovum is contained in the double decidua, as the head in a doubled night cap, and that each is probably an inspissated exudation at different periods from the uterus (Scarpa). Between the chorion and amnios, in the early months, a collection of gelatinous matter is found; perhaps with the vesicula lactea, to assist in the nutrition of the foetus, while the circulation is yet incomplete; and in the latter, this space is occasionally filled by a serous fluid, styled the false waters; so that every discharge of water, in pregnant women, is not dangerous. If not attended with a discharge of blood, it is apparently harmless. These waters, however, have led some physiologists into an error, who supposed, that they had discovered a receptacle for the urine, called in quadrupeds tbe allantois, an oblong membranous sac between the chorion and the amnios. No such receptacle, however, is found in the human subject.

The placenta, as we shall afterwards show, consists of two parts. One is apparently derived from the decidua, and has been supposed a spongy inorganic substance, for the purpose of attachment; but it contains numerous blood vessels which can be injected exclusively from the arteries of the mother. The remaining part of the cake is an organ of the foetus, and its vessels can only be injected from the umbilical cord. These facts, which are now well established, prove that no circulation is carried on between the mother and foetus in continuous vessels; nor can any considerable nerves, indeed scarcely any, be traced from the uterus to the foetus part of the placenta. The foetus has therefore a system peculiarly its own in every respect, indebted only to the mother for support, warmth, and a supply of nutriment.

When the blood, through the funis umbilicalis, reaches the abdomen of the foetus, it is carried to the liver; and one half of the whole mass circulates in that organ. In the earliest stages, the liver is peculiarly large; and this considerable proportion of the vital fluid is seemingly designed to nourish it, for the bile is colourless, and without taste. This viscus does not indeed lessen, but its proportion is diminished by a more rapid increase of the other parts, and in every organ where a peculiar organic structure is necessary nature seems to form it very early of a large size. This is the case with the eyes, the liver, the lymphatic system, & c.; nor, when the relative sizes are considered, is the genital system of either sex an exception. The remainder of the blood is carried by the ductus venosus to the vena cava, where also the blood, after having circulated through the liver, arrives. We thus trace it to the right auricle; but, as the lungs are not yet expanded by air, the pulmonary system cannot contain the whole quantity, and one part, but its proportion is not exactly-known, passes through the foramen ovale, a hole in the septum, which divides the auricles. The rest proceeds to the right ventricle; but of this portion only a part enters the pulmonary artery for the reasons assigned, and the rest is conveyed to the aorta, through a duct styled the ductus arteriosus. Thus the entire mass of fluids is conveyed to the aorta, to be circulated through the whole machine.

The nutrition of the foetus has occasioned many controversies. We may just mention a friendly one between the first Dr. Monro and Mr. Gibson, in the first and second volume of an excellent collection, though too much neglected, the Medical Essays of Edinburgh; because they contain a greater variety of facts, respecting the foetus, than are to be found in any other work. The subject may now be drawn within a narrow compass. The foetus is probably not nourished by the liquor amnii, because this fluid is not nutritious; it contains but a small portion of animal gelatine, and a large one of neutral salts, and is rather excrementitious than wholesome. If employed for this purpose, it probably is not swallowed, since there are no faeces collected in the bowels, for the meconium is only the inspissated bile, and other fluids of the intestines, which have acquired a colour from the delay; and no allantois to receive an excrementitious discharge. It is not probably absorbed; for the surface of the foetus when born is covered with mucus, apparently designed to prevent its irritation. This fluid, however, is now found to belong to the foetal part of the ovum; so that were every fact adduced in support of the nourishment of the foetus by the liquor amnii to be admitted, we must still seek for a supply. This supply is undoubtedly afforded by the mother; but it is still doubtful whether in the maternal part of the placenta the blood undergoes any preparation. We know of none; we can perceive none: it is apparently deposited in cells, and again absorbed.

Since, then, the connection of the foetus and the mother is so slight; since there are no continuous vessels, and scarcely any, if any, nervous communication; what reason can be assigned for the reported influence of the mother's imagination on the child, either in impressing any peculiar mark, more essentially changing an organic structure, or mutilating it, in consequence of seeing similar objects? Such influence

Is Wholly Unfounded; The Offspring Of Fancy, Supported By Accidental Facts, Often By Designed misrepresentations. Sound physiology denies every such connection; nor can it be established, without admitting a connecting ether or aura, which on any change made in the mother's system is followed by a corresponding one in the foetus. We shall leave the establishment of such an aura to the visionary supporters of sympathetic medicine, or the modern dreamers, who believe in animal magnetism. No such exists, or at least the influence of no such medium can be perceived.

If we examine the various facts adduced, the marks, for instance, we shall find that they are as often seen without any previous affection of the imagination as with it; that the resemblance, when such fancies have occurred, is distant, and often imaginary. If we look at the changes of organization, we shall find, often, that the shock has taken place when the. bones were firmly united, and when the disposition could not be changed without violent mechanical force : the fact mentioned by father Malebranche. where the limbs of the foetus were fractured, from the mother seeing a criminal broken on the wheel, is evidently false, or the circumstances greatly misrepresented. When, in the advanced period of gestation, the sight of a mutilated person is apparently followed by a similar mutilation of the child, the influence of the sight is highly improbable. What becomes of the mutilated limb? It may be supposed to be deprived of life, and absorbed, since it is never found; but the time required for such a process is far beyond the whole period of gestation, and the putrid limb, long before it would be completed, must produce a fever of the worst kind, for it must be remembered that the foetal blood returns to the mother. We might allege, that of ten thousands exposed to such sights, in perhaps only a single instance will the supposed consequence follow; and that it sometimes occurs without the previous spectacle. When both then happen, the concurrence must be pronounced accidental only. It is evident, however, that the foetus is affected by the complaints of the mother. It has in many instances shared her eruptive diseases; sometimes seemingly her fevers; more probably her nervous complaints. If, with the little connection which we have shown to take place, it can partake of these diseases, it may be supposed to suffer more essentially, or it may appear that we have too rashly denied any nervous communication. These influences are, however, much less considerable than authors have supposed. The agitations of the nervous system must be conveyed to an organ so peculiarly irritable as the uterus, and any spasmodic contractions of that organ must be felt by the foetus. The additional warmth also of the blood, in fever, may be supposed to affect the irritable little being, not yet born; and the matter of the small pox, which we can only trace, because this of all the febrile exanthema alone leaves any cicatrix, may undoubtedly be absorbed from the maternal part of the placenta. Nature, however, seems to have anxiously guarded against any communication, and the child often survives uninjured the most violent diseases of the mother.