HEREDITY AND GERMINAL CONTINUITY 321 



parent, etc., and arrived at the following conclusions: "The 

 parents together contribute one-half the total heritage, the 

 four grandparents together one-fourth, the eight great-grand- 

 parents one-sixteenth, and all the remainder of the ancestry 

 one- sixteenth." 



Karl Pearson has investigated this law of ancestral inher- 

 itance. He substantiates the law in its principle, but modifies 

 slightly the mathematical expression of it. 



This field of research, which involves measurements and 

 mathematics and the handling of large bodies of statistics, 

 has been considerably cultivated, so that there is in existence 

 in England a journal devoted exclusively to biometrics, which 

 is edited by Karl Pearson, and is entitled Biometrika. 



The whole subject of heredity is undergoing a thorough 

 revision. What seems to be most needed at the present time 

 is more exact experimentation, carried through several gen- 

 erations, together with more searching investigations into 

 the microscopical constitution of egg and sperm, and close 

 analysis of just what takes place during fertilization and the 

 early stages of the development of the individual. Experi- 

 ments are being conducted on an extended scale in endowed 

 institutions. There is notably in this country, established 

 under the Carnegie Institution, a station for experimental 

 evolution, at Cold Spring Harbor, New York, of which C. B. 

 Davenport is director. Other experimental stations in Eng- 

 land and on the Continent have been established, and we 

 are to expect as the result of coordinated and continuous 

 experimental work many substantial contributions to the 

 knowledge of inheritance. 



