By this term I mean, as already more than once explained, the preservation by
man of the most valued, and the destruction of the least valued individuals,
without any conscious intention on his part of altering the breed. It is
difficult to offer direct proofs of the results which follow from this kind of
selection; but the indirect evidence is abundant. In fact, except that in the
one case man acts intentionally, and in the other unintentionally, there is
little difference between methodical and unconscious selection. In both cases
man preserves the animals which are most useful or pleasing to him, and
destroys or neglects the others. But no doubt a far more rapid result follows
from methodical than from unconscious selection. The "roguing" of plants by
gardeners, and the destruction by law in Henry VIII.'s reign of all under-
sized mares, are instances of a process the reverse of selection in the
ordinary sense of the word, but leading to the same general result. The
influence of the destruction of individuals having a particular character is
well shown by the necessity of killing every lamb with a trace of black about
it, in order to keep the flock white; or again, by the effects on the average
height of the men of France of the destructive wars of Napoleon, by which many
tall men were killed, the short ones being left to be the fathers of families.
This at least is the conclusion of some of those who have closely studied the
effects of the conscription; and it is certain that since Napoleon's time the
standard for the army has been lowered two or three times.
Unconscious selection blends with methodical, so that it is scarcely possible
to separate them. When a fancier long ago first happened to notice a pigeon
with an unusually short beak, or one with the tail-feathers unusually
developed, although he bred from these birds with the distinct intention of
propagating the variety, yet he could not have intended to make a short-faced
tumbler or a fantail, and was far from knowing that he had made the first step
towards this end. If he could have seen the final result, he would have been
struck with astonishment, but, from what we know of the habits of fanciers,
probably not with admiration. Our English carriers, barbs, and short-faced
tumblers have been greatly modified in the same manner, as we may infer both
from the historical evidence given in the chapters on the Pigeon, and from the
comparison of birds brought from distant countries.
Public-domain text, read in full here on John Shaqi.
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