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See page in:
1859
1860
1861
1866
1869
1872

Compare with:
1859
1860
1861
1866
1872

→ the sub-breeds of the tumbler-pigeon) 1861 1866 1869 1872
tumbler-pigeons) 1859 1860
→ 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
→ (though it was a long time before I saw how), from 1861 1866 1869 1872
from 1859 1860
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 →the sub-breeds of the tumbler-pigeon) 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
become
became
greater, the inferior animals with intermediate characters, being neither very swift nor very strong,
will
would not
would
have been →neglected, and will
thus have
have
tended to
....
disappear.
disappeared.
Here, then, we see in
mans
man's
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
→(though it was a long time before I saw how), 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.
We can clearly
see
discern
this in the case of animals