BIOMETRIC IDEAS AND METHODS 63 



and what the utility of that measurement really is. 

 Failure to do this is bound to result in confusion 

 of thought. No description has any significance 

 unless the thing described has some meaning and 

 interest. Just here is where so much of the bio- 

 metrical work which has been done has failed. 

 Too often has there been an espousal of the forlorn 

 hope that the application of biometric methods 

 might inject biological interest and meaning 

 into a problem previously quite destitute of these 

 attributes. 



Further, it is of the highest importance for the 

 correct application of biometric methods to under- 

 stand thoroughly the biological implications of 

 the particular method employed. Failure to 

 do this is bound to lead one into all sorts of pit- 

 falls. It has been a very unfortunate boast of 

 some biometricians that their methods involved ' 

 no biological assumption or implication whatever. 

 Such a statement is seen upon critical examina- 

 tion to involve a logical difficulty. Biometric 

 methods, considered solely as pure mathematical 

 reasoning, certainly have no biological implica- 

 tions, but the moment they are applied to biological 

 data for the solution of biological problems they do 

 carry biological implications. Otherwise their 

 application is altogether irrational and futile. If 

 no biological meaning or implication attaches to 

 the determination of the degree of correlation 

 between parent and offspring, for example, it is 



