284 
THE PRINCIPLES 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 wdiilst 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 
