io8 THE SCIENCE OF LIFE. 



ordinated according to definite plans. As every change 

 must have an adequate cause, we are compelled to infer 

 the existence of a co-ordinating force behind the action 

 of the bioplasts in each organism. That force is the 

 cause of form in organisms. It has as many types as 

 there are types of organisms, vegetable and animal." * 

 The same subtle power which co-ordinates, also differen- 

 tiates the cells. This power resides in the original germ, 

 before the organization of the individual form, and is 

 what we have already defined as Life, and is not explica- 

 ble by physical causes. "Collocation of parts in an 

 organism is precisely what materialism has never yet 

 explained." f 



* " Heredity," by Joseph Cook, p. 46. f Cook's " Biology." 



