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 prime 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, which 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 readily surmised. 
Those who wish to examine Harvey’s views at first hand, 
without the burden of translating them from the Latin, will 
find an edition of his complete works translated into English 
by Willis, and published by the Ray Society, of London. 
As.is always the case with new truths, there was hostility 
