XL 

 EVOLUTION IN BIOLOGY. 



IN the former half of the eighteenth century, the 

 term " evolution " was introduced into biological writ- 

 ings, in order to denote the mode in which some of 

 the most eminent physiologists of that time conceived 

 that the generation of living things took place ; in op- 

 position to the hypothesis advocated, in the preceding 

 century, by Harvey in that remarkable work* which 

 would give him a claim to rank among the founders 

 of biological science, even had he not been the discov- 

 erer of the circulation of the blood. 



One of Harvey's prime objects is to defend and 

 establish, on the basis of direct observation, the opinion 

 already held by Aristotle; that, in the higher animals 

 at any rate, the formation of the new organism by the 

 process of generation takes place, not suddenly, by 

 simultaneous accretion of rudiments of all, or of the 

 most important, of the organs of the adult ; nor by 

 sudden metamorphosis of a formative substance into a 

 miniature of the whole, which subsequently grows ; but 



* The " Exercitationes dc Gencratione Animalium," which Dr. George 

 Ent extracted from him and published in 1651. 



