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1859
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his products be, 1859 1860 1861 1866
be his results, 1869 1872

every variation, even 1859 1860 1861 1866
OMIT 1869 1872

rejecting that which is 1859 1860 1861 1866
variations; rejecting those that are 1869 1872

1 blocks not present in 1859 1860; present in 1861 1866 1869 1872
In order that any great amount of modification should thus in the course of time be produced, it is necessary to believe that when a variety has once arisen, it again varies, after perhaps a long interval of time; and that its varieties, if favourable, are again preserved, and so onwards.

and the black-grouse that of peaty earth, 1859 1860 1861 1866
OMIT 1869 1872

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
Nature
during whole geological
periods!
periods.
Can we wonder, then, that
nature's
Nature's
Natures
productions should be far "truer" in character than
man's
mans
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
metaphorically be
said that natural selection is daily and hourly scrutinising, throughout the world, every variation, even the
slightest
slightest;
rejecting that which is bad, preserving and adding up all that
are
is
good; silently and insensibly working,
whenever
whenever
and
and
wherever
wherever
opportunity
opportunity
offers ,
offers,
at the improvement of each organic being in relation to its organic and
in organic
inorganic
conditions of life. We see nothing of these slow changes in progress, until the hand of time has marked the
long
long
lapse of ages, and then so imperfect is our view into
long-past
long past
geological ages, that we
see only
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,—
prey—
so much so, that on