No. 590] FECUNDITY IN THE DOMESTIC FOWL 



97 



freely and universally accepted by workers in genetics 

 lies in the fact that he has never presented his results in 

 such a form that any other interpretation of the data could 

 by any chance be tested. There is, from the methodolog- 

 ical standpoint, only one way in which an adequate test 

 can be made as to whether any observed change in the 

 composition of a population is the result of a sorting, or 

 of true germinal change, or an adequate idea gained of 

 how the change came about. This is the method of indi- 

 vidual pedigree analysis. Only one extensive mass selec- 

 tion experiment has ever been analyzed in this way, and 

 that is in Surface's 7 discussion of the Illinois corn results. 

 The Hagedoorns 8 called Castle 's attention two years ago 

 to the necessity of individual pedigrees before any just 

 opinion could be formed as to the meaning of the data. 

 To paraphase Castle's damning indictment of the present 

 writer I may be permitted to call attention to the fact that, 

 so far as concerns the individual pedigree of his rats, " in- 

 formation is denied us" by Castle. 



In bringing to a close this part of the discussion I wish 

 to emphasize that, in spite of Castle's assertion to the con- 

 trary, any unprejudiced person who will take the trouble 

 to examine the facts will find that, so far as concerns 

 methods of dealing with the data and presenting them for 

 publication, the method of their Mendelian analysis, the 

 method of presenting the results of selection experiments 

 by a series of averages, and other matters of method, my 

 work with fecundity in fowls exactly parallels at every 

 point Castle 's work with hooded rats, and is in every way, 

 so far as I am able to judge, exactly as critical as his. 

 His experiments are more extensive in scope than mine, 

 and the character fecundity is a more difficult one to deal 

 with, but so far as methodology is concerned the two re- 

 searches stand on precisely the same footing. I have not 



7 Surface, F. M., " The Kesult of Selecting Fluctuating Variations." 

 Data from the Illinois Corn Breeding Experiments. IV Conf. int. de Gen., 

 PP. 221-256, 1911. 



8 Hagedoorn, A. L. and A. C, "Studies on Variation and Selection," 

 Zeitschr. f. ind. Aist.—und Vererlungslehre, Bd. XI. pp. 145-83, 1914. 



