ii6 THE FAMILY AND THE NATION 



One thing becomes very clear : that we are dealing 

 with a large number of separate factors — various 

 types of ability, various degrees of unsoundness of 

 body and mind, various qualities of temper and 

 character. Longevity, proneness to certain diseases, 

 height, colour of hair and eyes, all may be tabulated 

 as separate entities, and their combinations, separations, 

 and re -combinations watched throughout succeeding 

 generations. 



As we said in the beginning of this chapter, a study 

 of the effects of marriages with heiresses is a study of 

 a speciahzed form of infertility, interesting chiefly on 

 account of its social and economic bearings, important 

 because of the frequency with which such marriages 

 occur, disastrous because the type of man who marries 

 an heiress is usually one who has something to offer, 

 ability or good breeding, in exchange for the fortune 

 which sometimes accompanies the heiress and causes 

 her to be considered a desirable wife. 



The whole subject has been admirably set out and 

 treated by Galton in his book on Hereditary Genius 

 under the title of " English Peerages, their Influence 

 upon Race." To this work the reader who desires 

 further details or wishes fully to grasp the bearings 

 of the problem is referred. 



We have already produced evidence to show that 

 infertility in its various manifestations is hereditary in 

 the same way as other mental and physical attributes. 

 We should therefore expect that a woman who is 

 either the sole issue of a marriage or one of two or 

 three children would prove infertile herself or produce 



