THE BIOMETRIC STUDY OF HEREDITY ;iU 



CHAPTER IV 



THE BIOMETRIC STUDY OF HEREDITY 



The biometricians are a comparatively young but 

 very important school of biologists, whose founder 

 is Mr. Francis Galton, Charles Darwin's first 

 cousin, and whose foremost adherent is Professor 

 Karl Pearson, to whom we owe the term biometry, 

 or biometrics. The characteristic of these workers 

 is that they study large numbers of individuals, or 

 individual characters ; that they express all facts 

 with the greatest exactness possible ; that they con- 

 sistently employ mathematical methods in all their 

 work ; and that they excel in the detection of 

 fallacies. Indeed they approach biological ques- 

 tions with a unique equipment in mathematics and 

 logic. 



A large number of conclusions of very various 

 kinds already stand to the credit of the biometri- 

 cians. In this chapter I intend to note the more 

 important of their researches which bear directly 

 upon the problems of heredity and variation. It is, 

 of course, a fair criticism that one should consider 

 these inquiries each in strict relation to the subject 

 of which it treats ; but, on the other hand, the dis- 

 tinctive peculiarities of the biometric method may 

 be held to justify this arrangement ; and tiie reader 

 will lind allusions to the work of this school when- 

 ever it bears directly upon the various subdivisions 

 of this book. It is necessary to remember that the 

 science of heredity is yet inchoate. The attempt to 



