246 HEREDITY IN RELATION TO EUGENICS 



scores of family names so that its family signification be- 

 comes lost. 



The facts that we have been considering above lead to 

 a conclusion quite in line with modern experimental work 

 in heredity and with the interpretation of varieties. The 

 white race as seen in America to-day is made up of thou- 

 sands, yes, hundreds of thousands of kinds of protoplasm 

 which differ by the possession of at least one determiner 

 for a peculiar, differentiating trait. The potential strains 

 that are constituted by these different kinds are not, how- 

 ever, real strains because they are constantly crossed into 

 other strains. Only when there is a high degree of con- 

 sanguineous marriage, as in small islands, or mountain val- 

 leys, is this potentiality realized. Otherwise the traits soon 

 become dissociated from the family names of those who 

 brought them to this country and they become dissemi- 

 nated into many related families. But the potentiality for 

 the production of a strain or race remains. 



Now the fact of the existence of such strains in this 

 country has an important bearing upon studies made on 

 man. For example, our text-books on anatomy give an 

 account of structure that is based on the finding of mmierous 

 autopsies. The original author of such a work records for 

 each organ and part the condition in which he has found 

 it in the material that he has dissected. If he goes into 

 enough detail he has to state in connection with each de- 

 scription that it does not hold universally but that, on the 

 contrary, in one cadaver or another this and that modi- 

 fication has been found. The name of the family to which 

 the cadaver belongs, its ancestral history, is usually not 

 given (and indeed it frequently cannot be obtained), but it 

 is important that it should be ascertained; if possible, for 

 the same reason that it is important to know if the cadaver 

 were of a Caucasian or a Chinaman. Indeed, as a text- 



