Constitution of the White Leghorn Breed. 213 



the games.* It suffices the present purpose to state that the barred 

 pattern did not appear in either Fi or F2 of the White Silky X Black 

 Hamburg crosses. 



In Fi of the matings between a White Minorca cf and Black 

 Hamburg 9 all the progeny were black, the d^ 6^ manifesting red 

 saddle feathers. In F2of this cross (1913) the results were: black 

 78, white 27, the expected being: black 78%, white 261^. No 

 barring appeared in either Fi or F2. 



V. General Summary and Conclusions. 



1. — In reviewing as a whole the results of the many crosses described 

 in the foregoing pages it becomes apparent that, as was stated at the 

 outset, the original aim of the investigation has not been realized. 

 The main purpose was (in 1909) to produce, and then to ''fix" the 

 barred plumage pattern by means of suitable matings of white with 

 dark birds, it being assumed tentatively that the barred plumage 

 pattern might represent, as many breeders have supposed, a hetero- 

 zygous condition of black and white, — a sort of a mosaic in the same 

 feather. It is true that a part of the aim has been attained, in so far 

 as a completely barred pattern was actually secured in F2 ; and a pure 

 strain of barred fowls has been built up from these barred F2 in- 

 dividuals. But a consideration of the nature of this barring, together 

 with a careful study of its manner of inheritance in the numerous 

 crosses mentioned above, leaves no doubt that it could not have been 

 produced de novo from the White X Black matings as first suspected, 

 but that it had its origin in a factor for barring present in the gametes 

 of the W. L. d^ . The evidence already presented indicates therefore 

 that the W. L. c?" is homozygous for this character B, while the 9 is 

 heterozygous. It also indicates that the W. L. cT" carries a factor, C, 

 or possibly other factors, for black pigmentation. This circumstance 

 would naturally bring out the barred pattern were it not for the 

 presence of an inhibiting fact, I, which represses the manifestation 

 of black, — a factor for which the W. L. cf is also homozygous. 



*This point, together with others which have arisen in the course of the investigations, will be 

 considered in detail in a later publication. 

 5 



