A CRITICAL EXAMINATION 9 



possible practically to delimit either category 

 precisely, and, for present purposes certainly, 

 this is not necessary. 



We may now turn to the second division of our 

 program. 



II. Methods of Research in Genetics 



1. The Biometric. 



The biometric mode of attacking the problem 

 of heredity owes its inauguration to the late Sir 

 Francis Galton, and its great development to 

 Professor Karl Pearson. Galton was the first to 

 perceive the importance of dealing with heredity 

 on a statistical basis. As Pearson has well said, 

 the recognition of this fact was one of the "greatest 

 services of Francis Galton to biometry." Merz l 

 has pointed out that Galton in his own mind 

 sharply separated the problem of heredity into 

 two parts, the one having to do with the material 

 basis of hereditary phenomena, the other with 

 the phenomena themselves. His early experi- 

 ments dealt with the first of these problems. 

 By means of blood transfusion he hoped to test 

 and further develop Darwin's theory of pangene- 

 sis. Certain now obvious technical difficulties of 

 dealing experimentally with the problem in this 

 way undoubtedly had much to do with turning 

 Galton to the study of the other phase, towards 



1 Merz, J. T. "A History of European Thought in the Nine- 

 teenth Century," Vol. II, p. 613, 1903. 



