INHERITANCE OF WINTER EGG PRODUCTION 115 



bounds of probability are not exceeded in considering the 2:8 

 ratio a chance deviation from equahty. The same sort of 

 reasoning apphes if we recognize three sorts of winter layers 

 instead of two. 



In order to secure families (i.e., progeny of a single pair) of 

 sufficient size, hatched at the proper time, and fulfilling the 

 other conditions necessary, it is necessary to repeat identical 

 matings of a critical nature through a period of years. To do 

 this would require huge physical facilities. It will therefore be 

 difficult to secure suitable data. 



There is another consideration that affects the application of 

 small observed ratios to theoretical ratios. Any individual is 

 placed in one of two (three, respectively) classes. It is obvious, 

 then, that ratios such as the following 1:0, 0:1, 1:1, 1:2, 2:1, 

 1:3, 3:1, 2:3, 3:2 and so on will occur as a matter of chance.*^ 

 It is obvious, furthermore, that only when it is possible to 

 obtain a really adequate number of female progeny, not less than 

 20 from each pair, will it become possible to determine definitely 

 whether or not either theory has any basis in fact. As Castle 

 ('15, '16) has maintained, we may be dealing with a character 

 that is purely Continuous in its variation. 



The ease with which any observed set of ratios in small families 

 can be made to fit at least one theoretical ratio is emphasized by 

 the changes in management as given in an earlier paragraph. 

 Thus, no difficulty is experienced in securing a close fit between 

 expected and theoretical ratios in 1914, although the egg pro- 

 duction of the progeny of the males used that year was entirely 

 different from that of the same males in other years. Of course 

 it is necessary to assign the males to different gametic classes in 

 the different years. Under such circumstances, it is obvious 

 that Mendelian ratios may not express the true mode of 

 inheritance of fecundity. 



^The series for three classes are 1:0:0, 0:1:0, 0:0:1. 1:1:0, 0:1:1,. 1:0:1, 

 1:1:1, 2; 1:0, 2:0:1, 0:2:1, and so on. 



