WHAT IS DARWINISM? 33 



tion having been effected since the glacial pe- 

 riod would be of some avail against those who 

 believe in an innate and necessary law of de- 

 velopment, but is powerless against the doc- 

 trine of natural selection, or the survival of 

 the fittest, which implies only that variations 

 or individual differences of a favorable nature 

 occasionally arise in a few species and are then 

 preserved." (p. 149) 



This process of improvement under the law 

 of natural selection includes not only chances 

 in the organic structure of animals, but also in 

 their instincts and intelligence. On entering 

 on this part of his subject, Mr. Darwin says, " I 

 would premise that I have nothing to do with 

 the origin of the primary mental powers, any 

 more than I have with that of life itself. We 

 are concerned only with the diversities of in- 

 stinct and of other mental qualities within the 

 same class." (p. 255) He shows that even in 

 a state of nature the instincts of animals of the 

 same species do in some degree vary, and that 

 they are transmitted by inheritance. A mas- 

 tiff has imparted courage to a greyhound, and 

 a greyhound has transmitted to a shepherd-dog 

 a disposition to hunt hares. Among sporting 

 dogs, the young of the pointer or . retriever 



