72 THE PRINCIPLES OF HEREDITY 



produced thirteen lambs, all perfectly black. Mr. Fox 

 believes that this ram belonged to a breed which he has 

 himself kept, and which is always spotted with black and 

 white ; and he finds that Leicester sheep crossed by rams of 

 this breed always produce black lambs ; and he has gone on 

 re-crossing these crossed sheep with pure white Leicesters 

 during three successive generations, but always with the 

 same result. Mr. Fox was also told by the friend from whom 

 the spotted breed was procured, that he had likewise gone on 

 for six or seven generations crossing with white sheep, but 

 still black lambs were invariably produced." l 



125. " My attention was first called to this subject, and I 

 was led to make numerous experiments, by MM. Boitard and 

 Corbie having stated that, when they crossed certain breeds 

 of pigeons, birds coloured like the wild Columba lima, or 

 the common dove namely slaty-blue, with double black 

 wing-bars, sometimes chequered with black, white loins, the 

 tail barred with black, with the outer feathers edged with 

 white were almost invariably produced. ... I selected^ 

 pigeons belonging to true and ancient breeds, which had not a 

 trace of blue or any of the above specified marks ; but when 

 crossed, and their mongrels re-crossed, young birds were often 

 produced, more or less plainly coloured slaty-blue, with some 

 or all of the proper characteristic marks. I may recall to the 

 reader's memory one case, namely, that of a pigeon hardly 

 distinguishable from the wild Shetland species, the grand- 

 child of a red spot, white fantail, and two black barbs, from 

 any of which, when purely bred, the production of a pigeon 

 coloured like the wild G. lima would have been almost a 

 prodigy." 2 



126. " I was thus led to make the experiments recorded in 

 the seventh chapter on fowls. I selected long-established 

 pure breeds in which there was not a trace of red, yet in 

 several of these mongrels feathers of this colour appeared ; 

 and one magnificent bird, the offspring of a black Spanish 

 cock and white Silk hen, was coloured almost exactly like the 

 wild G-allus bankiva. All who know anything of the breed- 

 ing of poultry will admit that tens of thousands of pure 

 Spanish and of pure white Silk fowls might have been reared 

 without the appearance of a red feather. The fact, given on 

 the authority of Mr. Tegetmeier, of the frequent appearance 

 in mongrel fowls of pencilled or transversely-barred feathers, 

 like those common to many gallinaceous birds, is likewise 



1 Animals and Plants, vol. ii., pp. 3, 4. 

 2 Op. cit., p. 14. 



