112 



BIOMETRY 



On the theory of pure lines it is to be noticed that 

 the personal character of a particular ancestor has 

 no influence upon his descendants ; it is only the 

 type of the line to which he belongs which influences 

 the offspring, so that this theory is in perfect agreement 

 with Weismann's theory of inheritance as described 

 on p. 68. 



It is also to be observed that the principle of the 

 pure line applies only to quantitative characters 

 such characters of size, or of weight, or of proportion, 

 as are very seldom made use of by systematists for 

 the distinction of natural species. 



