No. 576] SHORTER ARTICLES AND CORRESPONDENCE 761 



F x generation and found that this was accomplished in the F 25 

 generation, the amount of heterozygosis in each generation being : 

 F 6 , 75.000 per cent. F„, 94.312 per cent. F*, 98.710 per cent, 

 F T , 79.687 per cent. F ]4 , 95.398 per cent. F*, 98.956 per cent. 

 F s , 83.594 per cent. F^,, 96.277 per cent. F K , 99.155 per cent. 

 F 8 , 86.719 pe 



F«, 92.969 per cent. F 19 , 98.405 per cent. F^,, 99.638 per cent. 



With the approval of Dr. Castle and Dr. East I prepared to pub- 

 lish these figures. 



Shortly after this Dr. Pearl wrote to Dr. East asking for an 

 opinion upon his article. Dr. East, in the meantime, by a method 

 differing from mine,' had worked out the ratios independently. 

 Before answering Dr. Pearl's letter, however, Dr. East compared 

 his results with mine. They agreed. Dr. East then wrote to Dr. 

 Pearl, giving a short rebuttal of Dr. Pearl's arguments, enclosing 

 some of his own figures and adding that a student of Dr. Castle's 

 (myself) was thinking of publishing the complete figures. Dr. 

 Pearl immediately acknowledged his mistake and very gener- 

 ously asked if he should wait until I had published my article 

 before he published a correction. Dr. East replied that he could 

 see no. reason for delaying the correction and advised ] 

 reply. 



Since it seemed proper for Dr. Pearl to correct his 

 article, I decided to withhold my own figures and ir 

 them later in a paper bearing also upon other matters. Dr. 

 Pearl's second article came out in the American X.vtur.vltst for 

 January, 1914, and this paper together with the third article in 

 the same journal for June, 1914, shows that his work was en- 

 tirely independent of Dr. East's or my own. 



When Mr. Whiting asked me for a note giving the figures 

 showing what might be expected in the way of an automatic in- 

 crease in homozygosity when brothers were mated with sisters in 

 successive generations, as Mr. Whiting had done with his flies, I 

 naturally was pleased to have him accept my figures as correct- 

 ing his own, and at the same time give me an opportunity to ac- 

 knowledge my indebtedness to those who furnished the idea upon 

 which my figures were based. 



H. D. Fish 



Forest Hills, Mass. 

 August 18, 1914 



