ould not be affected by natural selection. It is not asserted
that natural selection induces variability. It implies only the
preservation of such varieties as arise and are beneficial to the being
under its conditions of life. Again, it has been said that I speak of
natural selection as an active Power or Deity; but who objects to an
author speaking of the attraction of gravity as ruling the movements of
the planets? It is difficult to avoid personifying the word Nature; but
I mean by Nature only the aggregate action and product of many natural
laws, and by laws the sequence of events as ascertained by us.

As man can produce, and certainly has produced, a great result by his
methodical and unconscious means of selection, what may not natural
selection effect? Man can act only on external and visible characters;
Nature, if I may be allowed to personify the natural preservation or
survival of the fittest, cares nothing for appearances, except in so far
as they are useful to any being. She can act on every internal organ, on
every shade of constitutional difference, on the whole machinery of
life. Man selects only for his own good; Nature only for that of the
being which she tends. Every selected character is fully exercised by
her, as is implied by the fact of their selection. Man keeps the natives
of many climates in the same country; he seldom exercises each selected
character in some peculiar and fitting manner; he feeds a long and a
short-beaked pigeon on the same food; he does not exercise a long-backed
or long-legged quadruped in any peculiar manner; he exposes sheep with
long and short wool to the same climate.

Man does not allow the most vigorous males to struggle for the females.
He does not rigidly destroy all inferior animals, but protects during
each varying season, as far as lies in his power, all his productions.
He often begins his selection by some half-monstrous form; or at least
by some modification prominent enough to catch the eye or to be plainly
useful to him.

But under Nature, the slightest differences of structure or constitution
may well turn the nicely-balanced scale in the struggle for life, and so
be preserved. How fleeting are the wishes and efforts of man! How short
his time! And, consequently, how poor will be his results compared with
those accumulated by Nature during whole geological periods! Can we
wonder that Nature's productions should be far "truer" in character than
man's produ