n have a somewhat monstrous
character. It is also a most favourable circumstance for the production of
distinct breeds, that male and female pigeons can be easily mated for life;
and thus different breeds can be kept together in the same aviary.

I have discussed the probable origin of domestic pigeons at some, yet quite
insufficient, length; because when I first kept pigeons and watched the
several kinds, knowing well how true they bred, I felt fully as much
difficulty in believing that they could have descended from a common
parent, as any naturalist could in coming to a similar conclusion in regard
to the many species of finches, or other large groups of birds, in nature.
One circumstance has struck me much; namely, that all the breeders of the
various domestic animals and the cultivators of plants, with whom I have
ever conversed, or whose treatises I have read, are firmly convinced that
the several breeds to which each has attended, are descended from so many
aboriginally distinct species. {29} Ask, as I have asked, a celebrated
raiser of Hereford cattle, whether his cattle might not have descended from
long-horns, and he will laugh you to scorn. I have never met a pigeon, or
poultry, or duck, or rabbit fancier, who was not fully convinced that each
main breed was descended from a distinct species. Van Mons, in his treatise
on pears and apples, shows how utterly he disbelieves that the several
sorts, for instance a Ribston-pippin or Codlin-apple, could ever have
proceeded from the seeds of the same tree. Innumerable other examples could
be given. The explanation, I think, is simple: from long-continued study
they are strongly impressed with the differences between the several races;
and though they well know that each race varies slightly, for they win
their prizes by selecting such slight differences, yet they ignore all
general arguments, and refuse to sum up in their minds slight differences
accumulated during many successive generations. May not those naturalists
who, knowing far less of the laws of inheritance than does the breeder, and
knowing no more than he does of the intermediate links in the long lines of
descent, yet admit that many of our domestic races have descended from the
same parents--may they not learn a lesson of caution, when they deride the
idea of species in a state of nature being lineal descendants of other
species?

_Selection._--Let us now briefly consider the steps by which domestic race