THE STUDY OF AMERICAN FAMILIES 249 



duction of our best protoplasm in proper matings and we 

 cannot have proper matings unless our best protoplasm is 

 located and known. The day may come when in intelli- 

 gent circles a woman will accept a man without knowing 

 his biologico-genealogical history with as much hesitation 

 as a stock-breeder will accept as a sire for his colts or calves 

 an animal without a pedigree. Since restriction of the num- 

 ber of children seems, for better or Worse, to be the fashion 

 with our older families, let every effort be put forth to secure 

 that each child shall be of the best quality in respect to 

 inborn capacities.^ 



3. The Integrity of Family Traits 



We often hear persons who are impressed by the multi- 

 plicity of one's ancestors make hght of family pride in some 

 preeminent forbear. They ask of what significance can 

 such an ancestor be whose blood is diluted to one part in 

 a thousand? This way of looking at heredity is a relic of 

 a former view that a trait when mated to its absence pro- 

 duced a half trait in the progeny as skin color was consid- 

 ered to do, and which gave rise to the conception of quad- 

 roons, octaroons, etc., with successive lightening of the skin 

 '^o %, % and so on. Now that we know that even skin 

 color may segregate out in the ancestral full grades we are 

 ready to accept as practically universal the rule that unit 

 characters do not blend; that apparent blends in a trait 

 are a consequence of its composition out of many units. 

 Since this is so, a unit character (especially a negative char- 

 acter) which a remote ancestor possessed may reappear, 

 after many generations have passed, in its pristine purity. 

 A germ plasm that produced a mathematical genius only 



1 The need for a full Family Record is, we may hope, about to be filled by 

 Dr. J. Madison Taylor of Philadelphia. Meanwhile those who wish a copy of 

 the Family Records of the Eugenics Record Office may obtain it on applica- 

 tion. 



