IX. 



ON THE HYPOTHESIS THAT ANIMALS AEE 

 AUTOMATA, AND ITS HISTORY. 



THE first half of the seventeenth, century is cne of 

 the great epochs of biological science. For though sug- 

 gestions and indications of the conceptions which took 

 definite shape, at that time, are to be met with in works 

 of earlier date, they are little more than the shadows 

 which coming truth casts forward ; men's knowledge was 

 neither extensive enough, nor exact enough, to show 

 them the solid body of fact which threw these shadows. 



But, in the seventeenth century, the idea that the 

 physical processes of life are capable of being explained 

 in the same way as other physical phenomena, and, 

 therefore, that the living body is a mechanism, was 

 proved to be true for certain classes of vital actions ; 

 and, having thus taken firm root in irrefragable fact, 

 this conception has not only successfully repelled every 

 assault which has been made upon it, but has steadily 

 grown in force and extent of application, until it is 

 now the expressed or implied fundamental proposition 

 of the whole doctrine of scientific Physiology. 



