FAMILIES OF INFERIOR ABILITY 



359 



low. Only twenty have been known to learn a trade and ten of 

 these did so while in state prisons. 



The story of the Juke family indicates that weakness of char- 

 acter and low mental ability will give rise to offspring with little 

 moral or mental stability. Although this study does not prove 

 that a tendency toward wrong-doing is inheritable, it certainly 

 does show, at least, that weak character and low mental ability 

 give rise to a person who often becomes a criminal. The Jukes 

 lack the judgment, memory, and will power that enable people to 

 fulfill responsibilities toward their fellow men. 



The Kallikak family (the name is fictitious) throws still more 

 light on human heredity. Martin Kallikak, a normal, healthy 



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Intelligence and lack of intelligence seem to be inherited characters. One of the lines of 

 descent of Martin Kallikak shows feeble-mindedness inherited from a feeble-minded mother. 

 Of 480 descendants studied, only 46 were known to be normal. The other line of 496 descend- 

 ants from Martin Kallikak and a normal wife was practically all normal. 



young soldier who fought in the American Revolution, had a son 

 by a feeble-minded girl. This son had a family of ten children from 



