CHAPTER VIII 

 EUGENICS AND EUTHENICS 



1. Heredity and Environment 



Admitting, as we must, the importance of hereditary 

 tendencies in determining man's physical traits, his behavior 

 and his diseases, we cannot overlook the question that must 

 occur to all— What relation have the facts of heredity to 

 those of environmental influence, to the known facts of in- 

 fection and bad conditions of life? Indeed, were we to 

 accept the teachings of some, environment alone is impor- 

 tant, good training, exercise, food, and sunlight can put 

 anybody'' in a ''normal" condition. 



So long as we regard heredity and environment as opposed 

 so long will we experience endless contradictions in interpret- 

 ing any trait, behavior or disease. The truth seems to be that 

 for human phenomena there is not only the external or en- 

 vironmental cause but also an internal or personal cause. 

 The result is, in most cases, the reaction of a specific sort of 

 protoplasm to a specific stimulus. For example, the contro- 

 versy as to the inheritableness versus the communicableness 

 of ''the itch'' receives a simple solution if we recognize that 

 there is an external agent, probably a parasite, that can, 

 however, develop only in persons who are non-immune. 

 Since such persons are rather uncommon and the absence of 

 immunity is inheritable, the disease tends to run in families 

 and can rarely be caught even through inoculation, by per- 

 sons outside such families. Even in cases where the heredi- 

 tary factor is universally admitted as in manic-depressive 



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