MOTION OF THE HEART AND BLOOD 



plants. This seems also to occur in insects which 

 hide away in winter and appear dead or show a 

 vegetative vitality. But that it happens in red- 

 blooded animals^ as frogs, turtles, or serpents may 

 justly be doubted. 



In larger, warmer, red-blooded animals there is 

 need for something with greater power to distribute 

 nourishment. So, to fishes, serpents, lizards, turtles, 

 frogs and such like, a heart is granted with both 

 an auricle and ventricle. Thus it is very true, as 

 Aristotle contended {Be Part. Animal., Lib. j), 

 that no red-blooded animal lacks a heart, by whose 

 beat the nourishing liquid is not only stirred up 

 more vigorously than by an auricle, but is propelled 

 farther and more quickly. 



In still bigger, warmer, and more perfect animals 

 with more fervent and spiritous blood, a more 

 robust and fleshy heart is needed to pump the nutri- 

 tive fluid with greater force and speed, on account 

 of the size and density of their bodies. Further, 

 because the more perfect animals need more per- 

 fect nourishment and more native heat, that the 

 aliment may be better concocted^ and delivered, 



^ Harvey just says "blooded animals." The oxygen carrying 

 pigment in invertebrates is not the iron containing hemoglobin but 

 a copper containing hemocyanin, which is not red colored. 



* It is interesting to watch the valiant groping towards the facts 

 regarding the oxygenation of blood in the lungs. The idea expressed 

 is that in order better to "perfect" blood from the food, more heat 

 is needed for the process in the liver, and, as was generally recog- 

 nized, a draft of air promoted burning and heating. But the tradi- 

 tional doctrines, which Harvey follows in his teleological speculations 



hi?] 



