ii6 THE KALLIKAK FAMILY 



laws of inheritance and the ultimate effect of the 

 operation. 



CONCLUSION AND RESUME 



The Kallikak family presents a natural experiment 

 in heredity. A young man of good family becomes 

 through two different women the ancestor of two lines 

 of descendants, the one characterized by thoroughly 

 good, respectable, normal citizenship, with almost 

 no exceptions ; the other being equally characterized 

 by mental defect in every generation. This defect was 

 transmitted through the father in the first generation. 

 In later generations, more defect was brought in from 

 other families through marriage. In the last genera- 

 tion it was transmitted through the mother, so that we 

 have here all combinations of transmission, which 

 again proves the truly hereditary character of the de- 

 fect. 



We find on the good side of the family prominent 

 people in all walks of life and nearly all of the 496 

 descendants owners of land or proprietors. On the 

 bad side we find paupers, criminals, prostitutes, drunk- 

 ards, and examples of all forms of social pest with which 

 modern society is burdened. 



From this we conclude that feeble-mi ndedness is 

 largely responsible for these social sores. 



