A CRITICAL EXAMINATION 11 



Galton himself was not able to solve com- 

 pletely the purely mathematical problems in- 

 volved in his study of heredity. This phase 

 of the work was undertaken by Pearson with 

 brilliantly successful results. He developed in- 

 dependently a very complete and adequate system 

 of dealing mathematically with biological data. 

 His results in this direction form a permanent 

 and epoch-making contribution to the working 

 technical equipment of science. The great value of 

 these results for the future development of biology 

 is not yet generally realized. Merz compares their 

 significance for biology to that of the mathemat- 

 ical inventions of Fourier for physics. I should 

 be inclined personally to rate them even higher. 



Pearson has applied this technique particularly 

 to the study of inheritance. The chief result in 

 his hands has been the elaboration of Galton's 

 "Law of Ancestral Inheritance." This law as 

 originally stated by Galton was as follows: 1 

 "There was found an average (contribution) of 

 one fourth from each parent and one sixteenth 

 from each grandparent. According to this geo- 

 metrical scale if continued indefinitely backward 

 the total heritage of the child would be accounted 

 for." Pearson 2 has put this in a more general form 

 which does not restrict the values of the fractional 



1 "Natural Inheritance," p. 195. 



2 Pearson, K. "The Law of Ancestral Heredity." Biometrika, 

 Vol. II, pp. 210-228, 1903. 



