GENERAL JNTKODUCTION. XXV 



It thus appears that, in addition to settling whether 

 there is complete or almost complete reversion in form as 

 well as in colour, there is the question as to whether the 

 blue colour and the characteristic bars can be easily eradi- 

 cated ; and the further question, can the prepotency of 

 any given breed be increased ? can a fantail, e. g., be 

 made prepotent over a pouter ? * 



Let me deal first with the coloration question. Can 

 the blue colour be altered, and the dark wing bars be 

 eradicated ? Fanciers, as stated above, seem to agree 

 that while in certain breeds wing bars may not appear for 

 many generations if pure-bred birds are used, they almost 

 invariably come to the surface when intercrossing is re- 

 sorted to ; and they also believe that when once estab- 

 blished it is a difficult matter getting rid of them. 



As it happens, I soon succeeded in getting birds 

 without wing bars by making crosses, which could hardly 

 a priori have been expected to give positive results. I 

 crossed a well-bred dai-k blue fantail, having all the charac- 

 teristic bars of a rock-pigeon, with a less well bred fan- 

 tail, also blue, with the exception of the croup, head, and 

 tail, in which there were a number of white feathers. 



On two separate occasions these blue fantails produced 

 a well-formed absolutely white fantail. I believe this is 

 an instance of partial reversion, the explanation being 

 that the white offspring took after a white parent of their 

 sire. Fantails are an old breed, and white fantails are 

 especially common. However unlikely the result may 

 to some appear, I was quite prepared for it from what I 

 had already learned about reversion and inbreeding. I 

 next crossed a white fantail cock (which I believed to be 

 inbred) with a blue pouter hen. According to the 

 prevalent view the offspring should have taken after the 

 blue pouter at least in colour and markings, but as it 

 happens the cross-bred bird — there was but one — is 



* I need not say that in experiments of this kind the desired results, if 

 they come at all, seldom come at once. Even in the most expert hands 

 there is a large percentage of failure, but happily from failures something 

 can generally be learned. 



