In 1813 Dr. W.C. Wells read before the Royal Society "An Account of a White Female, Part of whose Skin resembles that of a Negro." In this paper the author distinctly recognized the principle of natural selection, but applied it only to the races of man, and in man only to certain characters. After remarking that negroes and mulattoes enjoy an immunity from certain tropical diseases, he observed, first, that all animals tend to vary in some degree, and, secondly, that agriculturalists improve their domesticated animals by selection. He added that what is done in the latter case by art seems to be done with equal efficacy, though more slowly, by nature in the formation of varieties of mankind fitted for the countries which they inhabit. Again in 1831 Mr. Patrick Matthew published a work on "Naval Timber and Arboriculture," in which he put forth precisely the same view concerning the origin of species as that propounded by Mr. Wallace and by Darwin. Unfortunately for himself, the view was cursorily suggested in scattered passages of an appendix to a work on a different subject, so that it remained unnoticed until Mr. Matthew himself drew attention to it in 1860, after the publication of the "Origin of Species." We observe finally that Mr. Herbert Spencer, in an essay published in 1852, and republished six years later, contrasted the theories of the creation and the development of organic beings. He argued from the analogy of domestic productions, from the changes which the embryos of many species undergo, from the difficulty of distinguishing species and varieties, and from the principle of general gradation, that species have been modified; and he attributed the modification to the change of circumstances.