Darwin’s Examples
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the remains of the Lamarckian theory of use-inheritance need not any longer encumber the great explanation which has superseded that fallacious and unproven theory and has rendered it totally unnecessary.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 Encyclopædia 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.