HARVEY'S IDEAS OE EMBRYONIC 

 NUTRITION* 



IN HIS LETTER of April 28, 1652, to R. MoiTson, M.D., of Paris, Harvey regarded 

 it as "... a most certain fact . . . that the embryos of all red-blooded animals 

 are nourished by means of the umbilical vessels from the mother, and this in 

 virtue of the circulation of the blood. They are not nourished, however, im- 

 mediately by the blood, as many have imagijied, but after the mariner of 

 the chick in ovo, which is first nourished by the albumen, and then by the 

 vitellus . . ." (p. 608). 



After considering conception in the deer in the month of December, Harvey 

 had concluded that: "From all of what precedes it is manifest that in both the 

 classes of viviparous animals alluded to, those, namely, that are provided with 

 carunculae or cotyledons, and those that want them, and perhaps in viviparous 

 animals generally, the foetus in utero is not nourished otherwise than the 

 chick in ovo; the nutritive matter, the albumen, being of the same identical 

 kind in all. . . . And this is further obvious from the fact of the extremities of 

 the umbilical vessels, when they are drawn out of the afore-mentioned mucor, 

 looking completely white; a certain proof that they absorb this mucilage 

 liquefied only, and not blood. The same arrangement may very readily be 

 observed to obtain in the egg. 



"The human placenta is rendered uneven on its convex surface, and where 

 it adheres to the uterus, by a nimiber of tuberous projections, and it seems 

 indeed to adhere to the uterus by means of these; it is not consequently at- 

 tached at every point, but at those places only where the vessels pierce it in 

 search of nourishment, and at those where, in consequence of this arrange- 

 ment, an appearance as if of vessels broken short off is perceived. But whether 

 the extremities of these vessels suck up blood from the uterus, or rather a cer- 

 tain concocted matter of the nature of albuynen, as I have described the thing 

 in the hind and doe, I have not yet ascertaiiied" (p. 497). 



"It seems manifest, therefore, that the foetus in utero is not nourished by its 

 mother's blood, but by this albuminous fluid duly elaborated. It may even be, 

 perhaps, that the adult animal is not nourished immediately by the blood, but 

 rather by something mixed with the blood, which serves as the ultimate ali- 

 ment; as may perhaps be more particularly shown in our Physiology^ and 

 particular treatise on the Blood" (p. 498). 



In his letter of July 13, 1655 (old style), to "John Dan. Horst," he likewise 

 declared, "I only say (keeping silence as to any other channels), that the nutri- 



* All quotations not separately identified are from \Villis' cdiiion (London: 1847) of 

 Harvey's works. The italics and words in brackets were introduced by the compiler. More 

 annotations and comments were precluded bv the unavoidable limits set. 



f Harvey is not known to have written such a treatise. 



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