In its historical and political applications far more significant and pregnant than Darwin. For certain questions, such as nationality, etc., only here has a basis in nature been found. E.g., he corrects the Pole Duchinski, whose version of the geological differences between Russia and the Western Slav lands he does incidentally confirm, by saying not that the Russians are Tartars rather than Slavs, etc., as the latter believes, but that on the surface-formation predominant in Russia the Slav has been tartarised and mongolised; likewise (he spent a long time in Africa) he shows that the common negro type is only a degeneration of a far higher one.