long-backed or long-legged quadruped in any peculiar manner; he exposes
sheep with long and short wool to the same climate. He 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 his eye, or to be plainly useful
to him. Under nature, the slightest difference 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 his
products be, 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 be said that natural selection is daily and hourly scrutinising,
throughout the world, every variation, even the slightest; rejecting
that which is bad, preserving and adding up all that is 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
only see that the forms of life are now different from what they
formerly were.
Although natural selection can act only through and for the good of
each being, yet characters and structures, which we are apt to consider
as of very trifling importance, may thus be acted on. When we see
leaf-eating insects green, and bark-feeders mottled-grey; the alpine
ptarmigan white in winter, the red-grouse the colour of heather, and
the black-grouse that of peaty earth, we must believe that these tints
are of service to these birds and insects in preserving them from
danger. Grouse, if not destroyed at some period of their lives, would
increase in countless numbers; they are known to suffer largely from
birds of prey; and hawks are guided by eyesight to their prey, so much
so, that on
parts of the Continent persons are warned not to keep white pigeons, as
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