CHAPTER IV 



INFLUENCE OF ENVIRONMENT 



The development of an individual or the evolution of a race 

 is dependent upon the interaction of two sets of factors or causes, 

 the intrinsic and the extrinsic. The former are represented by 

 the organization of the germinal protoplasm, the latter by all 

 other conditions; the former are known as heredity or constitu- 

 tion, the latter as environment or education; or in the words of 

 Galton, these two sets of factors may be called "nature" and "nur- 

 ture." The great problem of development is the unraveling of 

 these two factors, the assignment of its true value to each, and 

 the ultimate control of development so far as this may be possible 

 through the knowledge thus gained. 



A. RELATIVE IMPORTANCE OF HEREDITY 

 AND ENVIRONMENT 



The distinction between these two factors of development is 

 generally recognized and the question of the relative importance 

 of the two has been discussed for ages. Which is the more im- 

 portant, constitution or environment? What characteristics are 

 due to nature and what to nurture? To what extent is man the 

 creature of heredity, to what extent the product of education? 

 The old question "Which of you by taking thought can add one 

 cubit to his stature," is a vital question to-day. To what extent 

 may nature be modified by nurture? To what extent may educa- 

 tion make up for deficiencies of birth? 



i. Former Emphasis on Environment. Formerly very great 



