202 THE PROBLEMS OF EVOLUTION 



of essentials. Nothing of significance in the organ- 

 ism can fail to have its foundations in the heritage; 

 no character or function can fail to be related to 

 the other parts and functions of the body; and 

 nothing in the individual can be without an asso- 

 ciation, direct or indirect but vital none the less, 

 with the factors of external environment. The 

 organism, whether we speak of individuals or of 

 species, is a resultant coordinative mechanism 

 which arises through the harmonious interaction 

 of a self-perpetuating physico-chemical complex, 

 its heritage, and the intricate complex of conditions 

 under which it develops. This essentially epige- 

 netic view is not uncommon; it is ably developed 

 by Child ^ and is accepted by most modern biol- 

 ogists. 



It is true that the recognition of these facts 

 justifies the opinion held by many evolutionists 

 that the environment is merely directive, but the 

 emphasis that has been given to their point of 

 view seems wholly unwarranted. Even though an 

 acquired character is the product of a basic herit- 

 age and of many factors in the body, brought to 

 expression by an external stimulus, the fact re- 

 mains that the external environmental factor is 

 essential to its production, and that the hereditary 

 basis is due in part to other environmental condi- 

 tions of past life. These contributions from the 



^ Child, C. M., Physiological Foundations of Behavior, Ch. Ill, 1924. 



