In semi-civilised countries, with little free communication, the spreading of a new sub-breed will be a slow process.

As soon as the points of value 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.

I will now say a few words on the circumstances, favourable or the reverse, to man's power of selection.