different
fashions prevail in different districts, leading to the preservation, and
consequently to the transmission, of all sorts of trifling peculiarities of
character. The same process will have been pursued with our fruit-trees and
vegetables, for the best will always have been the most largely cultivated,
and will occasionally have yielded seedlings better than their parents.

The different strains, just alluded to, which have been raised by different
breeders without any wish for such a result, and the unintentional
modification of foreign breeds in their new homes, both afford excellent
evidence of the power of unconscious selection. This form of selection has
probably led to far more important results than methodical selection, and
is likewise more important under a theoretical point of view from closely
resembling natural selection. For during this process the best or most
valued individuals are not separated and prevented crossing with others of
the same breed, but are simply preferred and preserved; but this inevitably
leads during a long succession of generations to their increase in number
and to their gradual improvement; so that finally they prevail to the
exclusion of the old parent-form.

With our domesticated animals natural selection checks the production of
races with any injurious deviation of {425} structure. In the case of
animals kept by savages and semi-civilised people, which have to provide
largely for their own wants under different circumstances, natural
selection will probably play a more important part. Hence such animals
often closely resemble natural species.

As there is no limit to man's desire to possess animals and plants more and
more useful in any respect, and as the fancier always wishes, from fashion
running into extremes, to produce each character more and more strongly
pronounced, there is a constant tendency in every breed, through the
prolonged action of methodical and unconscious selection, to become more
and more different from its parent-stock; and when several breeds have been
produced and are valued for different qualities, to differ more and more
from each other. This leads to Divergence of Character. As improved
sub-varieties and races are slowly formed, the older and less improved
breeds are neglected and decrease in number. When few individuals of any
breed exist within the same locality, close interbreeding, by lessening
their vigour and fertility, aids in their fi