284 THE PEINCIPLES OF Part II. 



stances have already been given with the breeds of the 

 fowl and pigeon ; and under nature analogous cases are 

 of frequent occurrence. With animals under domesti- 

 cation, but whether under nature I will not venture to 

 say, one sex may lose characters proper to it, and may 

 thus come to resemble to a certain extent the opposite 

 sex ; for instance, the males of some breeds of the fowl 

 have lost their masculine plumes and hackles. On the 

 other hand the differences between the sexes may be 

 increased under domestication, as with merino sheep, in 

 which the ewes have lost their horns. Again, characters 

 proper to one sex may suddenly appear in the other 

 sex ; as with those sub-breeds of the fowl in which the 

 hens whilst young acquire spurs ; or, as in certain 

 Polish sub-breeds, in which the females, as there is 

 reason to believe, originally acquired a crest, and sub- 

 sequently transferred it to the males. All these cases 

 are intelligible on the hypothesis of pangenesis ; for 

 they depend on the gemmules of certain units of the 

 body, although present in both sexes, becoming through 

 the influence of domestication dormant in the one sex ; 

 or if naturally dormant, becoming developed. 



There is one difficult question which it will be con- 

 venient to defer to a future chapter ; namely, whether 

 a character at first developed in both sexes, can be ren- 

 dered through selection limited in its development to 

 one sex alone. If, for instance, a breeder observed that 

 some of his pigeons (in which species characters are 

 usually transferred in an equal degree to both sexes) 

 varied into pale blue ; could he by long-continued 

 selection make a breed, in which the males alone should 

 be of this tint, whilst the females remained unchanged ? 

 I will here only say, that this, though perhaps not 

 impossible, would be extremely difficult ; for the natural 

 result of breeding from the pale -blue males would be 



