would be the Scotch verdict, "not proven." And this not because much, if
any, additional evidence of the actual wearing out of any variety has
turned up since, but because a presumption has been raised under which the
evidence would take a bias the other way. There is now in the minds of
scientific men some reason to expect that certain varieties would die out
in the long run, and this might have an important influence upon the
interpretation of the facts. Curiously enough, however, the recent
discussions to which our attention has been called seem, on both sides, to
have overlooked this.

But, first of all, the question needs to be more specifically stated. There
are varieties and varieties. They may, some of them, disappear or
deteriorate, but yet not wear out--not come to an end from any inherent
cause. One might even say, the younger they are the less the chance of
survival unless well cared for. They may be smothered out by the adverse
force of superior numbers; they are even more likely to be bred out of
existence by unprevented cross-fertilization, or to disappear from mere
change of fashion. The question, however, is not so much about reversion to
an ancestral state, or the falling off of a high-bred stock into an
inferior condition. Of such cases it is enough to say that, when a variety
or strain, of animal or vegetable, is led up to unusual fecundity or of
size or product of any organ, for our good, and not for the good of the
plant or animal itself, it can be kept so only by high feeding and
exceptional care; and that with high feeding and artificial appliances
comes vastly increased liability to disease, which may practically
annihilate the race. But then the race, like the bursted boiler, could not
be said to wear out, while if left to ordinary conditions, and allowed to
degenerate back into a more natural if less useful state, its hold on life
would evidently be increased rather than diminished.