94 HEREDITY AND SOCIAL FITNESS 



XVI. MARRIAGE SELECTION. 



Our conclusions concernmg the effect of selective matings have been 

 indicated in the preceding sections. This will accordingly consist largely 

 of a presentation of views as to certain factors conditioning such selection. 



At the risk of wearying the reader, we wish l^efore considering these 

 to recapitulate once more the effects of selective mating. All members 

 carry weaknesses; where these are relatively few or so slight as not to 

 seriousl}^ impair their efficiency, the chance of their marrying strength 

 in these traits is relatively great. In most instances a partner was 

 secured who supplied a higher grade of the trait or other valuable 

 characters. The trait is thus strengthened or the defect made good, 

 and does not again make its appearance unless there is subsequent 

 marriage into a strain having the same weakness or defect. In the 

 histories under consideration this has occurred in only a few cases, so 

 that the grosser defects have been practically blotted out from three 

 lines of this network. On the other hand, when defect has been marked 

 or a number of minor weaknesses has occurred in such combination 

 as to entail social inadequacy, mating has usually occurred with those 

 equally defective. Where these defects w^ere similar, the result has 

 been a fairly uniform type of inefficiency. Where the defects were 

 dissimilar, the result was a diversity of degenerate condition. We 

 may now inquire, A\Tiat w^ere the essential factors involved in these 

 matings? We will study these factors in the Rufer network, where the 

 most marked diversity occurs and where our data are more complete. 



There were several agencies at work here which resulted in the 

 separation of those members of the family showing superior mentality 

 and aggressiveness from their less fortunate brothers and sisters. 

 The factor determining the better mating has generally lain in the 

 superior endowment of the one who migrates. An example of this 

 occurs in Line C, whose founder secured an able, aggressive wife. 

 Subsequent removal of the couple to a part of the State where the 

 family was not known enabled their children to secure abler consorts, 

 which, for at least three members, meant marriage into better strains. 

 In the second generation of Line A, the cause which led to the separa- 

 tion of the superior from the inferior members of the fraternity, was 

 in the first instance the death of the father and the scattering of the 

 children among strangers. Later, the desire for better advantages led 

 the superior brother and sister to a different section of the State, 

 where they made better marriages than the two who remained behind. 

 Later generations of both branches have seen a repetition of this pro- 

 cess wdth further deviation from the inferior lines. Thus it was the 

 superior qualities which led to a new environment. This new environ- 

 ment meant enlarged opportunity, one of whose chief values lay in 



