432 Harvey's Ideas o£ Embryonic Nutrition 



same aliment farther elaborated, as if feeling a diviner influence, boasting a 

 higher grade of vegetative existence, the gelatinous mass of the body is changed 

 into flesh, the organs of motion are distinguished, the spirits are perfected, 

 and motion begins; nor is it any longer nourished like a vegetable, by the roots, 

 but, living the life of an animal, it is supported by the mouth" (p. 441-442). 



"These and other observations of the same kind [upon prenatal deglutition, 

 suckling, and intestinal contents] make it extremely probable that the chick 

 in ovo is nourished in a twofold manner, namely, by the umbilical and by 

 the mesenteric veins. By the former he imbibes a nourishment that is well nigh 

 perfectly prepared, whence the first-formed parts are engendered and aug- 

 mented; by the latter he receives chyle for the structure and growth of the 

 other remaining parts" (p. 440). 



"All admit this distinction of fluids. But I, as I have already said, distinguish 

 two albumens in the egg, kept separate by an interposed membrane, the more 

 external of which embraces the other within it, in the same way as the yolk 

 is surrounded by the albumen in general. I have also insisted on the diverse 

 nature of these albumens; distinguished both by situation and their surround- 

 ing membranes, they seem in like manner calculated for different uses. Both, 

 however, are there for ends of nutrition, the outermost, as that to which the 

 branches of the umbilical veins are earliest distributed, being first consumed, 

 and then the inner and thicker portion; last of all the vitellus is attacked, and 

 by it is the chick nourished, not only till it escapes from the shell but for 

 some time afterwards. 



"But upon this point we shall have more to say below, when we come to 

 speak of the manner in which the foetuses of viviparous animals are developed, 

 and at the same time demonstrate that these all derive their origin from eggs, 

 and live by a twofold albuminous food in the womb. One of these is thin- 

 ner, and contained within the ovum or conception; the other is obtained by 

 the umbilical vessels from the placenta and uterine cotyledons. The fluid of the 

 ovum resembles a dilute albumen in colour and consistence; it is a sluggish, 

 pellucid liquid, in all respects similar to that which we have called the col- 

 liquament of the egg, in which the embryo swims, and on which it feeds by the 

 mouth. The fluid which the foetus obtains from the uterine placenta by the 

 aid of the umbilical vessels is more dense and mucaginous, like the inspissated 

 albumen. Whence it clearly appears that the foetus in utero is no more nour- 

 ished by its parent's blood than is the suckling afterivards, or the chick in ovo; 

 but that it is nourished by an albuminous matter concocted in the placenta, 

 and not ujilike white of egg" (p. 447-448). 



The placenta "in like manner [as the liver], prepares for the foetus alimen- 

 tary matters which have come from the mother . . ." and ". . . so, too, the 

 placenta . . . abounds in an albuminous fluid, and is only to be found at the 

 period of pregnancy" (p. 563). 



Harvey did not hold these views because he rightly believed that the blood 



