n to suppose it is such a hindrance in the struggle
that those who have it disappear in consequence. It simply gets
cancelled in the course of generations by the adverse influences of
other stocks.

While biologists admit, or rather assert, that the peculiarity in the
blacksmith's arm which was born with him is transmissible, they deny, or
rather do not admit, that the other peculiarities of his arm, induced by
daily labour--its large muscles and strengthened bones--are
transmissible. They say that there is no proof. The Duke of Argyll
thinks that the inheritance of organs enfeebled by disuse is "not
generally disputed;" and he thinks there is clear proof that the
converse change--increase of size consequent on use--is also inherited.
But biologists dispute both of these alleged kinds of inheritance. If
proof is wanted, it will be found in the proceedings at the last meeting
of the British Association, in a paper entitled "Are Acquired Characters
Hereditary?" by Professor Ray Lankester, and in the discussion raised by
that paper. Had this form of inheritance been, as the Duke of Argyll
says, "not generally disputed," I should not have written the first of
the two articles he criticizes.

But supposing it proved, as it may hereafter be, that such a
functionally-produced change of structure as the blacksmith's arm shows
us, is transmissible, the persistent inheritance is again of a kind with
which natural selection has nothing to do. If the greatly strengthened
arm enabled the blacksmith and his descendants, having like strengthened
arms, to carry on the battle of life in a much more successful way than
it was carried on by other men, survival of the fittest would ensure the
maintenance and increase of this trait in successive generations. But
the skill of the carpenter enables him to earn quite as much as his
stronger neighbour. By the various arts he has been taught, the plumber
gets as large a weekly wage. The small shopkeeper by his foresight in
buying and prudence in selling, the village-schoolmaster by his
knowledge, the farm-bailiff by his diligence and care, succeed in the
struggle for existence equally well. The advantage of a strong arm does
not predominate over the advantages which other men gain by their innate
or acquired powers of other kinds; and therefore natural selection
cannot operate so as to increase the trait. Before it can be increased,
it is neutralized by the unions of those who have it with thos