Origin of Species Variorum

Comparison with 1872

When further improved by the same slow and gradual process, they will spread more widely, and will be 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 and knowledge of any new sub-breed will be a slow process. As soon as the points of value ... are once fully 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 civilisation 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.

Circumstances favourable to Man ' s Power of Selection.

I will now say a few words on the circumstances, favourable, or the reverse, to man's 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 kept. Hence, number is of the highest importance for success. On this principle Marshall has remarked, with respect to the sheep of parts of Yorkshire, .. "as they generally belong to poor people, and are mostly in small lots , they never can be improved." On the other hand,

When further improved by the same slow and gradual process, they will spread more widely, and will get 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 would be a slow process. As soon as the points of value in a new strain 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 civilisation 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.

Circumstances favourable to Mans Power of Selection.

I must now say a few words on the circumstances, favourable, or the reverse, to mans 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 kept; and hence this comes to be of the highest importance to success. On this principle Marshall formerly remarked, with respect to the sheep of parts of Yorkshire, that, "as they generally belong to poor people, and are mostly in small lots, .. they never can be improved." On the other hand,