INDIVIDUALS AND SPECIES 45 



conditions, such changes of environment could not 

 fail to produce characters hitherto not realized by 

 any of the individuals constituting the species. 



In view of the facts which have been considered 

 regarding the association of individuals and spe- 

 cies, it is a necessary conclusion that whatever 

 occurs in the individual is a part of the species. If 

 the onset of a new condition brings about the de- 

 velopment of new characters, they are as much a 

 part of the species as of the individual, for the 

 individual exists only as a component of the species. 

 If they disappear when the associated environ- 

 mental conditions disappear, they are none the 

 less a part of the species, for environment is as 

 much an essential in its existence as heritage. 



The great problem of evolution has hitherto 

 been treated as a question of the importance or 

 insignificance of these various factors. If a char- 

 acter appears only in the individual in response to 

 external conditions, can it be of importance in the 

 evolution of the species, or are those things which 

 come from within the only significant characters .^^ 

 This attitude seems a mistake. .How can anything 

 which appears in an organism, barring modifica- 

 tions due wholly to accident, such as mutilations, 

 fail to be of potential, if not of immediate and 

 obvious, evolutionary significance.'^ Keeping in 

 mind the facts laid down, that individuals exist 

 only as components of species, that heritage and 



