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fleeting of characters, have lately been exhibited as distinct at our poultry-shows. |
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views
explain what has sometimes been noticed —
that we know
about the origin or history of any of our domestic breeds. But, in fact, a breed, like a dialect of a language, can hardly be said to have
a
origin. A man preserves and breeds from an individual with some slight deviation of structure, or takes more care than usual in matching his best
and thus improves them, and the improved
slowly spread in the immediate neighbourhood. But
→they will as yet
hardly have a distinct name, and from being only slightly valued, their history will
disregarded. When further improved by the same slow and gradual process, they will spread more widely, and will
recognised as something distinct and valuable, and will then probably first receive a provincial name. In semi-civilised countries, with little free communication, the spreading
→of a
new sub-breed
be a slow process. As soon as the points of value
→OMIT
are once
acknowledged, the principle, as I have called it, of unconscious selection will always tend, — perhaps more at one period than at another, as the breed rises or falls in fashion, — perhaps more in one district than in another, according to the state of
of the inhabitants, — slowly to add to the characteristic features of the breed, whatever they may be. But the chance will be infinitely small of any record having been preserved of such slow, varying, and insensible changes. |
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Circumstances
favourable
to →
Man
'
s
Power
of
Selection.
|
| I
now say a few words on the circumstances, favourable, or the reverse, to
power of selection. A high degree of variability is obviously favourable, as freely giving the materials for selection to work on; not that mere individual differences are not amply sufficient, with extreme care, to allow of the accumulation of a large amount of modification in almost any desired direction. But as variations manifestly useful or pleasing to man appear only occasionally, the chance of their appearance will be much increased by a large number of individuals being
→Hence, number is
of the highest importance
success. On this principle Marshall
remarked, with respect to the sheep of parts of Yorkshire,
"as they generally belong to poor people, and are mostly
in
small
they never can be improved." On the other hand, nurserymen, from
large stocks of the same
are generally far more successful than amateurs in
new and valuable varieties. A large number of individuals of an animal or plant can
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