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THE AMERICAN NATURALIST [Vol. L 



lumped the data any more, nor have I " suppressed" data 

 any more than he has. On the contrary I have published 

 a great deal of exact data, in a series of papers from this 

 laboratory, regarding the character fecundity, its normal 

 variation, etc. 



VI 



The next point which Castle makes is that the changes 

 which occurred in mean flock production during the six- 

 teen years, for which figures were given in the paper which 

 he criticizes, were probably due to environmental, or at 

 least to non-genetic effects. In making this point he 

 calmly disregards all that I have ever published about the 

 experiments, the means taken to be sure that environ- 

 mental effects were not mistaken for genetic, etc., and 

 proceeds in his discussion as though all my work on the 

 subject had been absolutely uncritical and that I had never 

 given a thought to checking the correctness of the results. 

 In the first place he notes the changes in the numbers of 

 birds on which the average in different years are based, 

 and points out that these numbers change in a roughly in- 

 verse direction to the means. He then says : 



numbers possibly something to do with the result ? 

 They have not. Had Professor Castle been less eager to 

 demolish these fecundity results he might have noted that 

 I have repeatedly stated that since 1908 all birds in these 

 experiments have been kept in flocks of the same size, 

 namely 125 birds per flock. The number of such flocks 

 has at times varied, but not the number in each flock 9 ex- 

 cept by very small numbers, such as resulted from losses 

 by death, the necessity occasionally of putting a few extra 

 birds in a pen for a brief period and similar very minor 



