Variation and Selection; a Reply. 



Hy W. E. Castle, Forest Hills (Massachusetts), library 



Harvard University, Bussey Institution. MEW YORK 



(Eingegangen am 1. Ajiril 1914.) 



In a paper entitled "Studies on variation and selection" recently 

 published in this journal. Dr. and Mrs. Hagedooen criticise severely 

 a series of experiments with hooded rats, which I have for some years 

 been conducting' with a view to testing the effectiveness of selection. 

 That investigation of this question is worth while will. T think, be 

 questioned by uo one, in view of its vital connection with theories of 

 heredity as well as with economic practise; but a difference of opinion 

 may exist as to what methods are best suited to solve the question. 

 Concerning this I wish iu passing to say a few words. 



The criticism of my methods and results is based wholly on a 

 paper ol very general character in which a detailed description of either 

 methods or results was imjwssible. I have since pul)lished jointly with 

 Dr. Phillips a more complete account which, to those who may chance 

 to read it, renders most of these criticisms superfluous, but for the 

 benefit of those who may not read the fuller account referred to, I wish 

 to correct certain wrong impiessions which are likely to be received 

 from reading only the account of my critics. 



1. 1 am charged (page 163) with using in my selection 

 experiments foundation stock which was not known to be 

 genetically pure for the character to be studied. 



This criticism begs the question at issue. The question under 

 investigation was: — Do pure races exist or can they be prodnced. Given 

 a pure I'ace to start with, what need would there be of investigating 

 its purity? I began with those rats about whose ancestry I knew most, 

 and endeavored, as my critics did in their own abortive experiments, to 

 obtain races as pure as possible by mating like with like. But I have 

 not yet succeeded (nor did the Hauedoorn's) in obtaining pure races, 



Induktive Abstammuu^s- und Vertrbungelehre. XU. tj^ 



bIJTANICAl. 



UAKiv;-.N. 



