DARWIN, AND AFTER DARWIF 



AN' EXPOSITION- OF THE DARWINIAN THEORY 



AND A DISCUSSION OF 



POST-DARWINIAN QUESTIONS 



BY THE LATE 



GEORGE JOHN ROMANES, M.A., LL.D., F.R.S. 



Honorary Fellow of Gonville and Caius College, Cambridge 



III 



POST-DARWINIAN QUESTIONS 



ISOLATION 



AND PHYSIOLOGICAL SELECTION 



Cljicago 



THE OPEN COURT PUBLISHING COMPANY 



1906 



