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; 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. 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,
then, that Nature's productions should be far "truer" in character than
man's productions; that they should be infinitely better adapted to the
most complex conditions of life, and should plainly bear the stamp of
far higher workmanship?

It may metaphorically be said that natural selection is daily and hourly
scrutinising, throughout the world, the slightest variations; rejecting
those that are bad, preserving and adding up all that are good; silently
and insensibly working, WHENEVER AND WHEREVER OPPORTUNITY OFFERS, at
the improvement of each organic being in relation to its organic and
inorganic conditions of life. We see nothing of these slow changes in
progress, until the hand of time has marked the long lapse of ages, and
then so imperfect is our view into long-past geological ages that we see
only that the forms of life are now different from what they formerly
were.

In order that any great amount of modification should be effected in a
species, a variety, when once formed must again, perhaps after a long
interval of time, vary or present individual differences of the same
favourable nature as before; and these must again be preserved, and so
onward, step by step. Seeing that individual differences of the
same kind perpetually recur, this can hardly be considered as an
unwarrantable assumption. But whether it is true, we can judge only
by seeing how far the hypothesis accords with and explains the general
phenomena of nature. On the other hand, the ordinary beli