in any particular manner, were originally chosen. We must attribute the
result to the variations in these parts having been successively preserved,
and thus continually augmented; whilst other variations, excepting such as
inevitably appeared through correlation, were neglected and lost. Hence we
may infer that most plants might be made, through long-continued selection,
to yield races as different from each other in any character {220} as they
now are in those parts for which they are valued and cultivated.

With animals we see something of the same kind; but they have not been
domesticated in sufficient number or yielded sufficient varieties for a
fair comparison. Sheep are valued for their wool, and the wool differs much
more in the several races than the hair in cattle. Neither sheep, goats,
European cattle, nor pigs are valued for their fleetness or strength; and
we do not possess breeds differing in these respects like the race-horse
and dray-horse. But fleetness and strength are valued in camels and dogs;
and we have with the former the swift dromedary and heavy camel; with the
latter the greyhound and mastiff. But dogs are valued even in a higher
degree for their mental qualities and senses; and every one knows how
greatly the races differ in these respects. On the other hand, where the
dog is valued solely to serve for food, as in the Polynesian islands and
China, it is described as an extremely stupid animal.[530] Blumenbach
remarks that "many dogs, such as the badger-dog, have a build so marked and
so appropriate for particular purposes, that I should find it very
difficult to persuade myself that this astonishing figure was an accidental
consequence of degeneration."[531] But had Blumenbach reflected on the
great principle of selection, he would not have used the term degeneration,
and he would not have been astonished that dogs and other animals should
become excellently adapted for the service of man.

On the whole we may conclude that whatever part or character is most
valued--whether the leaves, stems, tubers, bulbs, flowers, fruit, or seed
of plants, or the size, strength, fleetness, hairy covering, or intellect
of animals--that character will almost invariably be found to present the
greatest amount of difference both in kind and degree. And this result may
be safely attributed to man having preserved during a long course of
generations the variations which were useful to him, and neglected the
others.