OF A CERTAIN PENNSYLVANIA FAMILY. 



87 



individuals to 1 who is socially unfit and 1 on the border-line of fitness, 

 whereas in the following generation all, that is a total of 47, are socially 

 efficient. In Line D, the proportion of the socially unfit rises from 

 being roughly one-half in generations 2 and 3, it becomes two-thirds 

 in the two following generations. A census of the latest generation, 

 10 years hence, will undoubtedly further increase this ratio, since 

 many of the markedly deficient couples are still reproducing, and most 

 of their children, though apparently defective, are at present too young 

 for accurate determination and representation in the figure. 



v//'//////A ^"■•'"-■■"'- 



MM 



Fig. 1. 



Here the type of unfitness, too, shows considerable range, includ- 

 ing vagrancy and petty criminality, sexual immorality, and in a few 

 instances, alcoholism and imbecility. In Line E, on the contrary, 

 there is the constant presence of social unfitness, generally in the form 

 of imbecility, amounting to 100 per cent. The significance of these 

 ratios will be further discussed in the section on marriage selection. 



In the same way, the ratio of the socially fit to the socially unfit in 

 successive generations of Lines F and G have been calculated and 

 represented graphically in figure 2. We find here a similar decrease 

 in the proportions of the socially unfit, as we proceed from the earlier 

 to the later generations. This decrease is less marked for Line F than 

 for Line G, and in the former case has taken place by the failure of 

 many of its deficient members (men) to secure life partners. It 

 should be observed that in Line G the large proportion of the socially 

 fit in generations 3 and 4 is reached by the inclusion of many dull and 

 backward individuals. They are not aggressive and have not moved 

 far from the original home of the family; many of them did not 

 advance far at school, but they possess great vitality and a dogged 



