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See page in:
1859
1860
1861
1866
1869
1872

Compare with:
1859
1861
1866
1869
1872

↑ 1 blocks not present in 1859 1860; present in 1861 1866 1869 1872
It will be admitted that the production of races so different as short-horn and Hereford cattle, race and cart horses, the several breeds of pigeons, &c., could never have been effected by the mere chance accumulation of variations of a similar character during many successive generations.
→ A fancier is 1859 1860
In practice, a fancier is, for instance, 1861 1866 1869 1872
→ tumbler-pigeons) 1859 1860
the sub-breeds of the tumbler-pigeon) 1861 1866 1869 1872
→ one man preferred 1859 1860 1861 1866 1869
of history, the men of one nation or district required 1872
→ another 1859 1860 1861 1866 1869
whilst those of another required 1872
→ by some breeders, 1859 1860 1861 1866 1869
in the one case, 1872
→ As 1859 1860 1861 1866 1869
Ultimately, after the lapse of centuries, these sub-breeds would become converted into two well-established and distinct breeds. As 1872
→ neglected, 1859 1860 1861 1866 1869
used for breeding, 1872
→ from 1859 1860
(though it was a long time before I saw how), from 1861 1866 1869 1872
this head from our domestic productions. We shall here find something analogous. ↑ →A fancier is struck by a pigeon having a slightly shorter beak; another fancier is struck by a pigeon having a rather longer beak; and on the acknowledged principle that "fanciers do not and will not admire a medium standard, but like extremes," they both go on (as has actually occurred with →tumbler-pigeons) choosing and breeding from birds with longer and longer beaks, or with shorter and shorter beaks. Again, we may suppose that at an early period →one man preferred swifter
horses,
horses;
→another stronger and
bulkier
more bulky
horses. The early differences would be very slight;
but, in
in
the course of time, from the continued selection of swifter horses →by some breeders, and of stronger ones
in the
by
other,
others,
the differences would become greater, and would be noted as forming two
sub-breeds.
sub-breeds;
finally,
finally,
after
after
the
the
lapse
lapse
of
of
centuries
centuries,
centuries,
the
the
sub-breeds
sub-breeds
would
would
become
become
converted
converted
into
into
two
two
well-established
well-established
and
and
distinct
distinct
breeds.
breeds.
→As the differences
slowly
slowly
became
become
greater, the inferior animals with intermediate characters, being neither very swift nor very strong,
would
would not
will
have been →neglected, and will
thus have
have
tended to
tended to
disappeared.
disappear.
Here, then, we see in
man's
mans
productions the action of what may be called the principle of divergence, causing differences, at first barely appreciable, steadily to increase, and the breeds to diverge in
character,
character
both from each other and from their common parent.
But how, it may be asked, can any analogous principle apply in nature? I believe it can and does apply most
efficiently
efficiently,
→from the simple circumstance that the more diversified the descendants from any one species become in structure, constitution, and habits, by so much will they be better enabled to seize on many and widely diversified places in the polity of nature, and so be enabled to increase in numbers.