A. W. Meyer 433 



of the mother does not circulate in the fetus, but because he held that in pre- 

 natal life the placenta plays the nutritional role that the mother plays in post- 

 natal life, and when discussing the role of the "humours"*— or uterine and 

 embryonic fluids— he declared, "... I nevertheless most confidently assert my 

 belief that these humours are at the commencement destined for the nourish- 

 ment of the foetus, just as the colliquament and albumen are in the case of 

 the chick; but that, in course of time, when the thinner and purer portions 

 are absorbed, the remainder takes on the character of excrementitious matter, 

 but still has its uses, and in some animals especially conduces to the safety of 

 the foetus, and also greatly facilitates birth. For just as wine becomes poor 

 and tasteless when the spirit has evaporated; and as all excreted matters owe 

 their origin for the most part to what has been previously food; so, after all 

 the nutrient portions of the fluid contained in the chorion have been taken 

 up by the foetus, the remainder becomes excrementitious, and is applied to 

 the above-mentioned uses. But all the fluid of the amnioji is usually consumed 

 by the time of birth; so that it is probable the foetus seeks its exit on account 

 of deficiency of nutriment" (p. 559). 



Although he thought of the conceptus as becoming attached to the uterus 

 for the purpose of taking up nutriment, Harvey emphasized that "At the 

 commencement the 'conception' (like an egg placed within the uterus) is found 

 in contact with every part of the uterus, yet at no point is it adherent; but 

 produces and nourishes the embryo out of the humours contained within it, 

 as I have explained in the instance of the hen's egg. This adhesion, or giowing 

 together, first takes place, and the fleshy mass (constituting the bond of union 

 between the 'conception' and the uterus) is first produced, when the foetus 

 becomes perfectly formed, and, through want either of different or more abun- 

 dant notirishment, dispatches the extremities of the umbilical vessels to the 

 uterus, that from hence (as plants do from the earth by their radicles), it may 

 absorb the nutrient juices. For in the beginning, as I have said, when the 

 'punctum saliens' and the blood can alone be seen, the ramifications of the 

 umbilical vessels are only visible in the colliquament and amnion. When, 

 however, the fabric of the body is completely formed, the ramifications extend 

 further, and are distributed in vast numbers throughout the chorion, that 

 from the albuminous fluid which there exists, they may obtain nourishment 

 for the foetus. 



"Hence it is manifest that the young of viviparous animals are at the begin- 

 ning nourished in exactly the same manner as the chick in the eg^; and that 

 they are detained within the uterus in order that (when they can no longer 

 supply themselves with nutriment from their own stores) they may form ad- 

 hesions to it by means of this fleshy substance, and receiving more abundant 

 supplies of food from the mother, may be nourished and made to grow. 



* By humours, as here used, Harvey understood both uterine and fetal fluids but he also 

 thought of the ovum or primordium of the new being, as "formed out of the humours of the 

 lUerus. " 



