CHAPTER IV 



BIOMETRY 



IN the present chapter we have to consider in some 

 detail the manner in which purely statistical methods 

 have been applied to certain biological data, a proceed- 

 ing to which the term biometry has been attached 

 by Professor Karl Pearson. Before concluding our 

 account we shall give a brief sketch of some of the 

 more important evidence bearing upon the problems 

 of evolution which has been brought to light by the 

 methods of biometrical science. 



The first investigator to apply the methods of 

 statistics to the solution of biological problems was the 

 Belgian astronomer, Quetelet. In 1845, in the form 

 of a series of letters addressed to the Grand Duke of 

 Saxe-Coburg and Gotha, Quetelet published an admir- 

 able account of the theory of probability and its 

 relation to human affairs, and one in which the use of 

 advanced mathematics was avoided. The pioneer of 

 biometry in this country is Francis Galton, whose book 

 on * Natural Inheritance ' embodies an extremely 

 lucid introduction to the statistical study of variation 

 and inheritance. From these two works are derived 

 most of the ideas submitted in the present chapter. 

 The more recent advances in biometry are mostly 



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