If gifted with these qualities, and he studies his subject for
years, and devotes his lifetime to it with indomitable perseverance, he
will succeed, and may make great improvements; if he wants any of these
qualities, he will assuredly fail. Few would readily believe in the natural
capacity and years of practice requisite to become even a skilful
pigeon-fancier.

The same principles are followed by horticulturists; but the variations are
here often more abrupt. No one supposes that our choicest productions have
been produced by a single variation from the aboriginal stock. We have
proofs that this is not so in some cases, in which exact records have been
kept; thus, to give a very trifling instance, the steadily-increasing size
of the common gooseberry may be quoted. We see an astonishing improvement
in many florists' flowers, when the flowers of the present day are compared
with drawings made only twenty or thirty years ago. When a race of plants
is once pretty well established, the seed-raisers do not pick out the best
plants, but merely go over their seed-beds, and pull up the "rogues," as
they call the plants that deviate from the proper standard. With animals
this {33} kind of selection is, in fact, also followed; for hardly any one
is so careless as to allow his worst animals to breed.

In regard to plants, there is another means of observing the accumulated
effects of selection--namely, by comparing the diversity of flowers in the
different varieties of the same species in the flower-garden; the diversity
of leaves, pods, or tubers, or whatever part is valued, in the
kitchen-garden, in comparison with the flowers of the same varieties; and
the diversity of fruit of the same species in the orchard, in comparison
with the leaves and flowers of the same set of varieties. See how different
the leaves of the cabbage are, and how extremely alike the flowers; how
unlike the flowers of the heartsease are, and how alike the leaves; how
much the fruit of the different kinds of gooseberries differ in size,
colour, shape, and hairiness, and yet the flowers present very slight
differences. It is not that the varieties which differ largely in some one
point do not differ at all in other points; this is hardly ever, perhaps
never, the case. The laws of correlation of growth, the importance of which
should never be overlooked, will ensure some differences; but, as a general
rule, I cannot doubt that the continued selection of sl