THE INHERITED IMPULSE. 145 



inheritance." As the latest stages of development 

 have been repeated the least, we see the explanation 

 of the fact that these newest characteristics are the 

 most likely to vary slightly in consecutive genera- 

 tions and in different individuals. Professor Haeckel 

 remarked that " heredity is memory " ; and in this 

 sense we may say that the latest developments have 

 not been thoroughly committed to memory, i.e. have 

 not been repeated often enough to become indissol- 

 ubly associated in the inherited impulse. 



