HEREDITY AND VARIATION 



to experimenting with peas. For some thirty-five 

 years his work was left unnoticed, but within the 

 last lustrum it has come into its own, his essential 

 discovery being now regarded by many, in Pro- 

 fessor Bateson's words, 1 as "one of the lasting tri- 

 umphs of the human mind." 



Until the rediscoveries which have brought Men- 

 del's work into recognition, the popular view was 

 simply this: like produces not exactly like; this 

 fortuitous difference between parent and child we 

 call variation; by the operation of natural selec- 

 tion favorable variations are perpetuated, and 

 unfavorable ones die out; hence, the origin of 

 species subsidiary factors being ignored as non- 

 existent by the school of Weismann, and as rel- 

 atively unimportant by the majority of biol- 

 ogists. 



But natural selection selects; it does not originate 

 or create. And all these decades past, while fully 

 discussing the consequences of variation, we have 

 ignored the fundamental question, simply accept- 

 ing it as a mysterious fact hardly likely to repay 

 investigation. Now, let me attempt to show what 

 Mendel and his successors of this generation have 

 accomplished, premising that the facts if not, 

 indeed, the interpretation of them are no longer 

 in dispute, and that they will be familiar to every 

 amateur student in a decade. How satisfactory 

 to the students of Herbert Spencer are these latest 



1 Presidential address to the section of zoology of the 

 ish Association, Cambridge, 1904. 

 117 



