HUMAN LIFE 



father and grandfather, Otto and F. G. 

 W. Struve, respectively, were also em- 

 inent astronomers, all three having been 

 gold medalists of the Royal Astronomical 

 Society. Three sons of Charles Darwin 

 have shown mental capacity above the 

 average. 



But if unusual mental capacity is 

 heritable so also is unusual mental in- 

 capacity, and because marked incapacity 

 becomes a social danger or, at least, 

 burden, much special study has been 

 given it in recent years. The matter 

 interests not only students of heredity, 

 but sociologists, educators, and criminol- 

 ogists. For mental incapacity or in- 

 sufficiency revealed in children as marked 

 backwardness and feeble-mindedness per- 

 sists in adults as feeble-mindedness and 

 imbecility, and poses a series of grave 

 problems concerning the social relations 

 of these unfortunates. 



One of the most interesting practical 

 outcomes of this intensive study of mental 

 sub-normalcy has been the development 

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