Five years after this, another pre-Darwinian was unearthed, and, like Patrick Matthew, in unsuspected company. Dr. W. C. Wells read a paper before the Royal Society in 1813 on a White Female Part of whose Skin resembles that of a Negro, but this was not published till 1818, when it formed part of a volume including the author's famous Two Essays upon Dew and Single Vision. In his Historical Sketch Darwin says that Wells "distinctly recognises the principle of natural selection, and this is the first recognition which has been indicated; but he applies it only to the races of man, and to certain characters alone.... Of the accidental varieties of man, which would occur among the first few and scattered inhabitants of the middle regions of Africa, some one would be better fitted than the others to bear the diseases of the country. This race would consequently multiply, while the others would decrease; not only from their inability to sustain the attacks of disease, but from their incapacity of contending with their more vigorous neighbours." When the simplicity of the long-hidden solution is brought home, we can understand Huxley's reflection on mastering the central idea of the Origin: "How extremely stupid not to have thought of that!" Twelve years elapsed before Darwin followed up his world-shaking book with the Descent of Man. But the ground had been prepared for its reception in the decade between 1860 and 1870. Quoting Grant Allen's able summary of the advance of the theory of Evolution in his Charles Darwin: "One by one the few scientific men who still held out were overborne by the weight of evidence. Geology kept supplying fresh instances of transitional forms; the progress of research in unexplored countries kept adding to our knowledge of existing intermediate species and varieties. During those ten years, Herbert Spencer published his First Principles, his Biology, and the remodelled form of his Psychology; Huxley brought out Man's Place in Nature, the Lectures on Comparative Anatomy, and the Introduction to the Classification of Animals; Wallace produced his Malay Archipelago and his Contributions to the Theory of Natural Selection (Bates, we may here add to Mr. Allen's list, published his paper on Mimicry in 1861, and his Naturalist on the Amazons in 1863); and Galton wrote his admirable work on Hereditary Genius, of which his own family is so remarkable an instance. Tyndall and Lewes had long since signified their warm adhesion. At Oxford, Rolleston was bringing up a fresh generation of young biologists in the new faith; at Cambridge, Darwin's old university, a whole school of brilliant and accurate physiologists was beginning to make itself both felt and heard. In the domain of anthropology, Tylor was welcoming the assistance of the new ideas, while Lubbock was engaged on his kindred investigations into the Origin of Civilization and the Primitive Condition of Man. All