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THE POPULAR SCIENCE MONTHLY 



which give the results of a portion of the actual experiments. As the 

 experiments were rather extensive, it is not possible here to present 

 anything like the complete material. Only representative matings are 

 here given. Table II. gives the results of some of the B. P. R. X B. P. B. 

 matings in detail, in order to show, not only the accordance between 

 observation and theory, but also the distinctness of the classes of fecun- 

 dity segregated (shown by the average winter production in each segre- 

 gated class). 



From the data set forth in the above table there can be no doubt as 

 to the fact of the Mendelian segregation of fecundity, nor as to the 

 entire distinctness of the things segregated. 



In order to give a general survey of the results, and to demonstrate 

 the reality of segregation over the wide range of material included in 

 the experiments, the summary Table III is presented. 



Table III 



Showing the Observed and Expected Distribution in Respect of Fecundity of the 

 Adult Female Offspring from all Matings in each of the Classes Tested 



in the Experiments 



Considering the nature of the material and the character dealt with 

 the agreement shown between observation and hypothesis is certainly 

 as close as could reasonably be expected. Such discrepancies as are 

 shown in the above table are fully discussed and their probable physio- 

 logical explanations set forth in detail in the complete account of these 

 experiments. 



The detailed data given in the complete paper, of which the above 

 discussion and tables give merely a very incomplete abstract, appear 

 definitely to establish the following points: 



1. That fecundity in the domestic fowl is inherited strictly in 

 accordance with Mendelian principles. 



2. That observed individual variations in fecundity here depend 

 upon two separately inherited physiological factors, L x and L 2 . 



3. That high fecundity is manifested only when both of these factors 

 are present together in the same individual. 



4. That either of these factors when present alone whether in homo- 



