52 BIOLOGY AND ITS MAKERS 



most of the blood return to the heart; (VIII) the blood does 

 return to the heart by way of the veins. It will be noticed 

 that the proposition VII is the important one; in it is 

 involved the idea of applying measurement to a physiological 

 process. 



Harvey's Influence. — Harvey was a versatile student. 

 He was a comparative anatomist as well as a physiologist 

 and embryologist; he had investigated the anatomy of about 

 sixty animals and the embryology of insects as well as of 

 vertebrates, and his general influence in promoting biological 

 work was extensive. 



His work on the movement of the blood was more than 

 a record of a series of careful investigations; it was a land- 

 mark in progress. When we reflect on the part played in 

 the body by the blood, we readily see that a correct idea of 

 how^ it carries nourishment to the tissues, and how it brings 

 away from them the products of disintegrated protoplasm is 

 of prim.e importance in physiology. It is the point from 

 which spring all other ideas of the action of tissues, and until 

 this was known the fine analysis of vital processes could not 

 be made. The true idea of respiration, of the secretion by 

 glands, the chemical changes in the tissues, in fact, of all the 

 general activities of the body, hinge upon this conception. 

 It was these consequences of his demonstration, rather than 

 the fact that the blood moves in a circuit, w^hich made it so 

 important. This discovery created modern physiology, and 

 as that branch of inquiry is one of the parts of general biology, 

 the bearing of Harvey's discovery upon biological thought 

 can be readilv surmised. 



Those who wish to examine Harvey's views at first hand, 

 without the burden of translating them from the Latin, wnll 

 find an edition of his complete works translated into English 

 by Willis, and published by the Ray Society, of I>ondon. 



As is always the case with new truths, there was hostility 



