98 WILLIAM HARVEY 



What is commonly said in regard to these two great com- 

 munications, to wit, that they exist for the nutrition of the 

 lungs, is both improbable and inconsistent; seeing that in 

 the adult they are closed up, abolished, and consolidated, 

 although the lungs, by reason of their heat and motion, must 

 then be presumed to require a larger supply of nourishment. 

 The same may be said in regard to the assertion that the 

 heart in the embryo does not pulsate, that it neither acts 

 nor moves, so that nature was forced to make these com- 

 munications for the nutrition of the lungs. This is plainly 

 false; for simple inspection of the incubated egg, and of 

 embryos just taken out of the uterus, shows that the heart 

 moves in them precisely as in adults, and that nature feels 

 no such necessity. I have myself repeatedly seen these mo- 

 tions, and Aristotle is likewise witness of their reality. 

 " The pulse," he observes, " inheres in the very constitu- 

 tion of the heart, and appears from the beginning as is 

 learned both from the dissection of living animals and the 

 formation of the chick in the egg." 1 But we further observe 

 that the passages in question are not only pervious up to 

 the period of birth in man, as well as in other animals, as 

 anatomists in general have described them, but for several 

 months subsequently, in some indeed for several years, not 

 to say for the whole course of life; as, for example, in the 

 goose, snipe, and various birds and many of the smaller 

 animals. And this circumstance it was, perhaps, that im- 

 posed upon Botallus, who thought he had discovered a 

 new passage for the blood from the vena cava into the left 

 ventricle of the heart; and I own that when I met with the 

 same arrangement in one of the larger members of the 

 mouse family, in the adult state, I was myself at first led 

 to something of a like conclusion. 



From this it will be understood that in the human embryo, 

 and in the embryos of animals in which the communications 

 are not closed, the same thing happens, namely, that the 

 heart by its motion propels the blood by obvious and open 

 passages from the vena cava into the aorta through the 

 cavities of both the ventricles, the right one receiving the 

 blood from the auricle, and propelling it by the pulmonary 



1 Lib. de Spiritu, cap. v. 





