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Wallace, Alfred Russel, 1823-1913

"Darwinism (1889)"


When any particular flower becomes fashionable and is grown in large
quantities, variations are always met with sufficient to produce great
varieties of tint or marking, as shown by our roses, auriculas, and
geraniums. When varied leaves are required, it is found that a number of
plants vary sufficiently in this direction also, and we have zonal
geraniums, variegated ivies, gold and silver marked hollies, and many
others.

_Variations of Domestic Animals._
Coming now to our domesticated animals, we find still more extraordinary
cases; and it appears as if any special quality or modification in an
animal can be obtained if we only breed it in sufficient quantity, watch
carefully for the required variations, and carry on selection with
patience and skill for a sufficiently long period. Thus, in sheep we
have enormously increased the wool, and have obtained the power of
rapidly forming flesh and fat; in cows we have increased the production
of milk; in horses we have obtained strength, endurance, or speed, and
have greatly modified size, form, and colour; in poultry we have secured
various colours of plumage, increase of size, and almost perpetual
egg-laying.


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