150 mr. darwin's work, etc. 



greatest contribution which has been made to biological 

 science since the publication of the " Regne Animal " 

 of Ciivier, and since that of the " History of Develop- 

 ment," of Yon Baer. I believe that if you strip it of 

 its theoretical part it still remains one of the greatest 

 encyclopaedias of biological doctrine that any one man 

 ever brought forth ; and I believe that, if you take it as 

 the embodiment of a hypothesis, it is destined to be the 

 guide of biological and psychological speculation for the 

 next three or four generations. 



