Moreover, the authors who have denied the existence of mixed races, have not denied that there are in Europe and elsewhere, numerous vivacious populations, formed by the intermixture of two or several distinct races. They merely asserted that mongrel breeds, whatever their origin, were necessarily inferior in reference to fecundity to individuals of pure blood, and that their direct descendants would become extinct after a few generations, unless they contracted new alliances with the mother races, or at least with one of them. If we object to this, that the mixed populations possess everywhere, as those of France and Great Britain, a vitality and fecundity which leaves nothing to be desired, they reply that this proves nothing; that the cross breeds are prolific in a collateral line, as is observed in cases of paragenesic hybridity, and they add that two cases may present themselves: 1. If among the two primitive races these obtain a very large numerical inequality, the predominant race soon absorbs the other. After two or three generations, the less numerous race counts scarcely one representative, and the cross-breeds are fused in the more numerous race. The latter thus returns to a state of original purity. The mixed race has only a transitory duration, and leaves no trace of its existence. 2. If, on the contrary, the two races, though numerically unequal, are in sufficient proportion that neither can absorb the other, both persist indefinitely beside each other upon the same soil. The hybrid race which they engender, seems also to persist indefinitely; but only in appearance, for they constantly intermarry with the pure races, while the latter marry between themselves. The mixed race gains thus, in every generation, a contingent equal to what it loses, those which represent it at present are not the descendants of those who represented the mixed race five or six generations back. It is not maintained by itself: existing only under the condition of being sustained by the races from which it is issued, and if there arrived a time when it is completely isolated from these two races, and reduced to its own forces, it would necessarily become extinct after a few generations. I might urge some objection against the first point, for it does not seem to me to be demonstrated, that in a mixture of very unequal proportions, the less numerous race exercises _no influence_ upon the other race. I acknowledge, however, that this influence, if it exists, is sufficiently slight to be set aside.