SCOPE OF GENETICS 43 



would be interesting, but its importance is 

 greatly increased by the fact that we know 

 two cases in birds which are closely compar- 

 able. The simpler case to which alone I shall 

 refer has been observed in the Canary. Like 

 the Currant moth it has a kind of albino, 

 called Cinnamon, and males of this variety 

 when mated with ordinary dark green hen 

 canaries produce dark males and Cinnamons 

 which are always hens ; while the green male 

 and the Cinnamon hen produce nothing but 

 greens of both sexes. This case, which has 

 been experimentally studied by Miss Durham, 

 offers a certain complication, but in its main 

 outlines it is exactly like that of the moth, and 

 the same interpretation is applicable to both. 

 The particular interpretation may be im- 

 perfect and even partially wrong; but that we 

 are at last able to form a working idea of the 

 course of such phenomena at all is a most 



