EVOLUTION 99 



tions accumulate, and its combined forces and 

 activities turn now this way, now that. We 

 think of the totality of these changes as tak- 

 ing place through a process of evolution by 

 which not only novel features arise, but the 

 rich inheritance of the past is preserved and 

 handed on. When we reflect on the means by 

 which this social growth is accomplished, we 

 are driven to admit that it is in reality the indi- 

 vidual man. He it is, who, working with his fel- 

 lows, accomplishes all. What he inherits, what 

 he devises, what he can hand on, these are the 3y 

 elements that make up the totality of social 

 evolution. Did we but know with certainty 

 how all this change comes about, many of 

 our most momentous social problems would be 

 solved. 



To many naturalists of the Darwinian period 

 an experimental laboratory for the study of 

 evolution would have seemed to be resources 

 thrown away. These older workers supposed 

 evolution to proceed at so slow a pace that an 

 experimental investigation of it would be im- 

 possible, but for somewhat over a decade and 

 mainly in consequence of the discovery of Men- 

 del's writings, the study of evolutionary prob- 

 lems from the experimental standpoint has 



