112 THE FAMILY AND THE NATION 



With the one marriage in generation IV. we reach 

 the turn of the tide. The future of the two families 

 depended on one individual B, Had that individual 

 married into another infertile stock, it is probable that 

 both families would have become extinct. But the 

 stock chosen happened to be a very fertile one, and 

 two children resulted. One of these children again 

 married into a strong and fertile stock and had a large 



Pedigree II. — Infertility 



0=f=0 



=0 © 0=f=0 #=0 OrO 



^ = married, without family. ^= unmarried. 



family. Thus two alliances with fertile blood re-estab- 

 lished the families we are considering when they were 

 well-nigh gone. 



A second family, totally unconnected in blood and 

 locality with the previous example, shows the same 

 phenomenon of infertility. 



Here a large family of marked ability has dwindled 

 away in two generations in precisely the same manner ; 

 we see the same evidence of correlated forms of infer- 

 tility in the sterile marriages, the two small families of 

 one and two children respectively, who in their turn did 

 not marry, and in the three unmarried members of the 

 original large family. There is no symptom of any 



