178 THE PROBLEMS OF EVOLUTION 



they are not necessarily a source of deep concern in 

 the problem before us. 



At the outset of its individual existence the body 

 of the organism takes over the control of its en- 

 vironment in some degree. It has been guaranteed 

 the attainment of autonomy, barring accidents, by 

 the actions of its parents; it may be guaranteed a 

 certain amount of protection and training during 

 the more vulnerable period of its infancy; but its 

 own body thereafter provides properly for the 

 gradual consummation of the remaining steps in 

 its development and adult life. It is still subject 

 to external and internal influences which lead to 

 modification, but it is self-determinative within 

 certain limits. In this condition all of the factors 

 in organic existence are realized. Heritage, internal 

 environment, and the physical and organic factors 

 of external environment, are all operative in shap- 

 ing the course and development of the indi\ddual. 

 Nothing which appears in it during its normal life 

 can be separated from the heritage; none of its 

 characters can fail to involve factors in the internal 

 environment; and none can be without a funda- 

 mental association, direct or indirect, with the 

 conditions which the organism encounters in the 

 world about it. 



The concept of the origin of life which follows 

 inevitably from the physico-chemical interpreta- 

 tion of the organism and from modern evolution is 



