PKEFACE TO THE AMEEICAK EDITION. 



The publication of Mr. Darwin's work on the 

 " Origin of Species," whether we consider the import- 

 ance of the questions it raises, the ability with which 

 he treats them, the boldness and originality of his 

 speculations, or the profound and universal interest 

 which the book awakened, must be looked upon as 

 marking an era in the progress of science. But while 

 it called forth a due share of candid discussion and 

 intelligent criticism, it has been vehemently and per- 

 sistently assailed by many who understood nothing of 

 its real character ; and the subject has hence been so 

 overloaded with prejudice and perversion that unscien- 

 tific people hardly know what to think or believe about 

 it. In these circumstances, those who disencumber the 

 subject of its difficulties, simplify its statements, relieve 

 it of technicalities, and bring it so distinctly within the 

 horizon of ordinary apprehension that persons of com- 

 mon sense may judge for themselves, perform an in- 



