The most formidable cases brought forward by Mr. Spencer are from
Darwin. I shall endeavour to show, however, that Darwin was probably
wrong in retaining the older explanation of these facts, and that the
remains of the Lamarckian theory of use-inheritance need not any longer
encumber the great explanation which has superseded that fallacious and
unproven theory and has rendered it totally unnecessary. Meanwhile I
think it is an excellent sign that Mr. Spencer has to complain that
"Nowadays most naturalists are more Darwinian than Mr. Darwin
himself"--inasmuch as they are inclined to say that there is "no proof"
that the effects of use and disuse are inherited. Other excellent signs
are the recent issue of a translation of Weismann's important essays on
this and kindred subjects,[15] the strong support given to his views by
Wallace in his _Darwinism_, and their adoption by Ray Lankester in his
article on Zoology in the latest edition of the _Encyclopaedia
Britannica_. So sound and cautious an investigator as Francis Galton had
also in 1875 concluded that "acquired modifications are barely, if at
all, _inherited_, in the correct sense of that word."
Darwin's belief in the inheritance of acquired characters was more or
less hereditary in the family. His grandfather, Erasmus Darwin,
anticipated Lamarck's views in his _Zoonomia_, which Darwin at one time
"greatly admired." His father was "convinced" of the "inherited evil
effects of alcohol," and to this extent at least he strongly impressed
the belief in the inheritance of acquired characters upon his
children's minds.[16] Darwin must also have been imbued with Lamarckian
ideas from other sources, although Dr. Grant's enthusiastic advocacy
entirely failed to convert him to a belief in evolution.[17]
"Nevertheless," he says, "it is probable that the hearing rather early
in life such views maintained and praised may have favoured my upholding
them under a different form in my _Origin of Species_"--a remark which
refers to Lamarck's views on the general doctrine of evolution, but
might also prove equally true if applied to Darwin's partial retention
of the Lamarckian explanation of that evolution. Professor Huxley has
pointed out that in Darwin's earlier sketch of his theory of evolution
(1844) he attached more weight to the inheritance of acquired habits
than he does in his _Origin of Species_ published fifteen years
later.[18] He appears to have acquired the belief in early life without
first questioning and rigorously testing it as he would have done had it
originated with himself. In later life it appeared to assist his theory
of evolution in minor points, and in particular it appeared absolutely
indispensable to him as the _only_ explanation of the diminution of
disused parts in cases where, as in domestic animals, economy of growth
seemed to be practically powerless. He failed to adequately notice the
effect of panmixia, or the withdrawal of selection, in causing or
allowing degeneracy and dwindling under disuse; and he hardly attached
sufficient importance to the fact that rudimentary organs and other
supposed effects of use or disuse are quite as marked features in
neuter insects which cannot transmit the effects of use and disuse as
they are in the higher animals.