[29] _Origin of Species_, p. 80, 6th ed. (1872). Here we have what may perhaps be regarded as a glimmering of the distinction between monotypic and polytypic evolution. But that it is only a glimmering is proved by the immediately ensuing sentences, which apply this analogy of unconscious selection _not_ to the case of monotypic, _but_ to that of polytypic evolution. So likewise, in the succeeding discussion on "divergence of character," the analogy is again resorted to for the purpose of showing how polytypic evolution may occur in nature. Thus far, then, it may be said that we have scarcely so much as a glimmering of the distinction between monotypic and polytypic evolution; and as the same discussion (with but a few verbal alterations) runs through all the editions of the _Origin_, it may well be asked why I should have alluded to such passages in the present connexion. Well, I have done so because it is apparent that, during the last years of his life, the distinction between selection as "methodical" and "unconscious" enabled Darwin much more clearly to perceive that between evolution as monotypic and polytypic. Thus in 1868 he wrote to Moritz Wagner (who, as we shall presently see, entirely failed to distinguish between monotypic and polytypic evolution), expressing his belief-- That in many large areas all the individuals of the same species have been slowly modified, in the same manner, for instance, as the English racehorse has been improved, that is, by the continued selection of the fleetest individuals, without any separation. But I admit that by this process two or more new species could hardly be formed within the same limited area[30]. [30] _Life and Letters_, vol. iii. p. 158. Again, in 1876 he wrote another letter to Wagner, in which the following passage occurs:-- I believe that all the individuals of a species can be slowly modified within the same district, in nearly the same manner as man effects by what I have called the process of unconscious selection. I do not believe that one species will give birth to two or more new species as long as they are mingled together within the same district[31]. [31] _Ibid._ p. 159. Two years later he wrote to Professor Semper:-- There are two different classes of cases, it appears to me, viz. those in which species becomes slowly modified in the same country, and those cases in which a species splits into two, or three, or more new species; and, in the latter case, I should think nearly perfect separation would greatly aid in their "specification," to coin a new word[32]. [32] _Ibid._ p. 160.