EVOLUTION AND HEREDITY. 13/ 



of the special biological problems which Galton^ set 

 before himself to solve by anthropology, were : (i) The 

 share contributed to the offspring by each of its several 

 ancestors. The nearness of kinship of different degrees 

 of relation. (2) The causes of stability of type observed 

 in large populations through many generations. (3) 

 Nature v. Nurture, or the share contributed by inheri- 

 tance and environment respectively to personal charac- 

 teristics. 



I. Stature is an heritage which blends ^ and which 

 therefore enables us to determine with precision the 

 contribution of each ancestor. We find that the mid- 

 parent contributes \ the total heritage ( = father \, 

 mother \ with transmutation for sex). The mid-grand- 

 parent ( = grandfather 3V' grandmother -3^ contributes 

 ■^g, etc. There is in every one an unused or " latent " 

 heritage as shown by the fact of his transmitting ances- 

 tral peculiarities he himself does not exhibit, but the 

 store of latent heritage is not necessarily from all or 

 even from many of his ancestry. As the personal heri- 

 tage from each parent is but one quarter, the total being 

 one half, it follows that both the personal and latent 

 heritages must be reduced by one half. 2. In heredi- 

 tary inquiry we must study fraternities and compare all 

 the members of one generation with those of another. 

 The main line of hereditary connection unites the set of 

 elements out of which both the parent and the child are 

 evolved. The main line is a chain of which the personali- 

 ties ai'e pendants. Stable forms represent the groupings 



1 See his " English Men of Science," " Inquiries into Human Faculty," 

 and " Natural Inheritance." 



2 Eye color is an example of characters which do not blend. 



