504 



ZOOLOGY 



Recessive 

 characters 



Scientific 

 heraldry 



9. It has been suggested that whereas many of the 

 inherited human defects are recessive, it does not matter 

 if one possessing them marries a normal person. The 

 children will be cross-bred, to be sure, but they will 

 appear normal. They in turn will probably marry 

 normal individuals, and the pernicious determiners will 

 never lead to any recurrence of the objectionable 

 characters. With regard to this it must be said, in the 

 first place, that such cross-bred individuals may not 

 be wholly normal. In some cases the heterozygous 

 individuals may be decidedly different from homozy- 

 gous (pure-bred) dominants, and experienced breeders 

 say that among plants and animals they can often pick 

 them out by critical inspection. More serious, how- 

 ever, is the fact that the recessive qualities do not dis- 

 appear from the stream of inheritance ; their deter- 

 miners go from generation to generation, ready to 

 produce effects as soon as a chance combination brings 

 them together. Thus they are a trap laid for posterity, 

 and after perhaps one or several hundred years two 

 persons may come together, each with an unknown 

 determiner for feeble-mindedness. One fourth of the 

 offspring will then, on the average, be feeble-minded, 

 and people will wonder at the inscrutable ways of 

 Providence. 



10. To what extent may group C include measures 

 taken to increase good qualities ? This is a far more 

 difficult problem, since the complexity of human in- 

 heritance is so great. Yet it may be desirable and 

 prudent to pay more attention to the family record, 

 as well as to the personal attainments of individuals. 

 Strong objections would be raised to the publication 

 of a mass of unfavorable data, but we can imagine a 

 new sort of heraldry, by which families would be 



