MOTION OF THE HEART AND BLOOD 



artery, and likewise constantly is drawn into the 

 left ventricle from the lungs, as is obvious from 

 what has been said and the position of the valves, 

 it cannot do otherwise than flow through contin- 

 uously. Then, as blood constantly pours into the 

 right ventricle of the heart, and constantly moves 

 out of the left, it is impossible, for the same reasons 

 as above, obviously reasonable, for it to do otherwise 

 than pass continually from the vena cava to the 

 aorta. 



It is evident from dissection that this occurs 

 through wide open channels in all animals before 

 birth, and from Galen's words and what has been 

 said previously it is equally manifest that it occurs 

 in adults by tiny pores and vascular openings through 

 the lungs.^ So it appears that, whereas one ventricle 

 of the heart, the left, suffices for distributing blood 

 to the body, and drawing it from the vena cava, as 



^ It is interesting to note how much Harvey relies on the tradi- 

 tional authorities to prove his points. The only contemporary au- 

 thority referred to is R. Columbus (1516-1559), although M, Ser- 

 vetus (1509-1553), and A. Caesalpinus (1524-1603) had also described 

 the pulmonary circulation. The latter, indeed, had discussed the 

 general circulation, so naming the phenomenon, and had postulated 

 vasa in capillamenta resoluta, or anastomoses between arteries and 

 veins. Dr. J. C. Hemmeter (Johns Hopkins Hosp. Bull., 16: 165, 

 1905) suggests, in his excellent essay, that since both Servetus and 

 Caesalpinus had offended the theologians, Harvey was afraid to men- 

 tion them. It has been observed (Chap. IV, Note 6) that Harvey 

 apparently had little fear of theological consequences. In view of 

 Harvey's honesty it is hard to believe that he really knew of the work 

 of these men. The "vascular openings" between arteries and veins 

 were first demonstrated in the frog's lung by Marcello Malpighi 

 (1628-1694), first great histologist. 



[67] 



