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or modify most of our plants up to their present standard of usefulness to man, we can understand how it is that neither Australia, the Cape of Good Hope, nor any other region inhabited by quite uncivilised man, has afforded us a single plant worth culture. It is not that these countries, so rich in species, do not by a strange chance possess the aboriginal stocks of any useful plants, but that the native plants have not been improved by continued selection up to a standard of perfection comparable with that
the plants in countries anciently civilised. |
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| In regard to the domestic animals kept by uncivilised man, it should not be overlooked that they almost always have to struggle for their own food, at least during certain seasons. And in two countries very differently circumstanced, individuals of the same species, having slightly different constitutions or structure, would often succeed better in the one country than in the
and thus by a process of "natural selection," as will hereafter be more fully explained, two sub-breeds might be formed. This, perhaps, partly explains
→what
has been remarked by some authors,
→namely, that the varieties kept by savages
have more of the character of
than the varieties kept in civilised countries. |
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| On the view here given of the
part which selection by man has played, it becomes at once obvious, how it is that our domestic races show adaptation in their structure or in their habits to
wants or fancies. We can, I think, further understand the frequently abnormal character of our domestic races, and likewise their differences being so great in external
and relatively so slight in internal parts or organs. Man can hardly select, or only with much difficulty, any deviation of structure excepting such as is externally visible; and indeed he rarely cares for what is internal. He can never act by selection, excepting on variations which are first given to him in some slight degree by nature. No man would ever try to make a
till he saw a pigeon with a tail developed in some slight degree in an unusual manner, or a pouter till he saw a pigeon with a crop of somewhat unusual size; and the more abnormal or unusual any character was when it first appeared, the more likely it would be to catch his attention. But to use such an expression as trying to make a fantail, is, I have no doubt, in most cases, utterly
The man who first selected a pigeon with a slightly larger tail, never dreamed what the descendants of that pigeon would become through long-continued, partly unconscious and partly
selection. Perhaps the
→parent bird of
fantails had only fourteen tail-feathers somewhat expanded, like the present Java fantail, or like individuals of other and distinct breeds, in which as many as seventeen tail-feathers have been counted. Perhaps the first pouter-pigeon did not inflate its crop much more than the turbit now does the upper part of its œsophagus, — a habit which is disregarded by all fanciers, as it is not one of the points of the breed. |
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| Nor let it be thought that some great deviation of structure would be necessary to catch the
eye: he perceives extremely small differences, and it is in human nature to value any novelty, however slight, in
own possession. Nor must the value which would formerly
set on any slight differences in the individuals of the same species, be judged of by the value which
now
set on them, after several breeds have
fairly been established.
→Many slight differences might, and indeed do now, arise amongst pigeons, which
are rejected as faults or deviations from the standard of perfection
each breed. The common goose has not given rise to any marked varieties; hence the
and the common breed, which differ only in colour, that
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