330 



[July, 



they again only to their daughters. Interesting support of 

 this view is derived from the results of castrating henny 

 cocks. It is well known that castration of normal cocks has no 

 marked effect, and that the plumage of the capon is similar to 

 that of the uncastrated bird. Castration of the henny cock, 

 however, results in the bird assuming the normal cock plumage 

 at the moult. This was first demonstrated by Morgan and 

 Goodale in America, and has since been confirmed by Dr. 

 F. H. A. Marshall in Cambridge. Plate 2 shows the skins of 

 a henny cock, and of a castrated henny cock which, after moult- 

 ing, assumed the plumage of a normal Brown Leghorn. Before 

 castration this bird closely resembled the henny cock shown in 

 Plate 2, Fig. 1. 



We must suppose that in the henny cock, as in the hen, the 

 henny type of feathering is due to some substance circulating 

 in the blood, inhibiting the production of normal male 

 feathering. Moreover, this substance must be produced by the 

 genital gland in the henny cock as in the hen. It may be pro- 

 duced by a testis as vrell as by an ovary. The hen is not hen- 

 feathered in virtue of her femaleness, but because she has 

 received from her mother a definite factor which she transmits 

 only to her daughters in the sex-linked w^ay. At some time or 

 other in the history of the fowl this factor went, as it were, 

 astray, and entered into a male -producing egg ; though how this 

 came about we do not at present know. When, however, the 

 dislocation happened it became possible to take advantage of it, 

 and to build it up as a breed character. It is well known that 

 the henny Sebright Bantams owe this peculiarity to a casual 

 henny bantam cock that Sir John Sebright noticed about a 

 century ago. Whatever may be the economic outcome, it is 

 evident that the analysis of such cases as that of the henny cock 

 is giving us a clearer insight into the problem of secondary sexual 

 characters, which can never be neglected by the breeder.* 



A few words may be said of some experiments undertaken in 

 order to investigate the characters of egg-colour and broodiness 

 in poultry.! That we were unable to work out these characters 

 in the way that we desired is due to circumstances brought 

 about by the War. When they were planned tliere was 

 a fair prospect of funds being found for the extension of the 



* A full account of this case will be found in the following- paper :— 

 Genetic Studies in Poultry. III. Ilen-feathered cocks, l)y R. C. Punnett and 

 the late P. G. Bailey. Journal of Genetic,^, XI, 1921. 



t Genetic Studies in Poultry. II. Inheritance of Egg colour and Broodi- 

 ness, by R. C. Punnett and the late P. G. Bailey. Journal of Genetics, X, 1920. 



