lOG H. D. GOODALE AND GRACE MACMULLEN 



of male 3003, as given elsewhere, every case encountered falls 

 into line. The data, therefore, are reduced to a harmonious 

 whole — a fact that speaks strongly for the validit}^ of both 

 theories. It is also noteworthy, where families are large, 

 that they fit the scheme with practically no difficulty. We do 

 not feel entirely confident, however, that it would be possible 

 to accomplish the same results with a really adequate series of 

 data, in which the families are of sufficient size. On the other 

 hand, it is certain that one could use either scheme as a guide 

 in breeding only if one knew definitely the gametic constitution 

 of the birds he started with. This knowledge can be obtained 

 either by a series of breeding tests extending over several years 

 or else one must have available a progeny from each mother of 

 twenty or more daughters. It is impossible to start as we have 

 done and make the progeny and parental tests agree except by 

 constant shifting of birds among the various gametic classes. 



One family, sired by male no. 8027, when a division point at 

 60 eggs is used, fails to show a good agreement between observed 

 and theoretical ratios on Pearl's theory, due to a deficiency in 

 the expected number of birds laying over 60 eggs among the 

 daughters of high producers. Such a deficiency is explicable, in 

 part at least, because of the ease with which a record can be 

 depressed below the division point, tlirough environmental or 

 managerial factors, for 60 eggs is at or near the maximum pro- 

 duction for birds beginning to lay December I. Thus, it is easy 

 to understand why a portion of the daughters do not reach 60 

 eggs. 



The only real exception to the application of Pearl's theory to 

 our Rhode Island Red data is the case of the famih^ ^ired by 

 male no. 3003. The detailed data of this mating are given in 

 tables 6 and 7. 



In some respects the production of the daughters of this male 

 is similar to that of the daughters of the Cornish male described 

 in another section. In 1915 male no. 3003 was mated to several 

 poor-producing birds, primarily in order to secure a flock of 

 non-broody Rhode Island Reds. As will be observed from the 

 table, all his offspring are either mediocre or zero producers. 



