the inferior than to the superior race. It soon disappears, and gives place to a race which may represent, in a mental respect, a kind of mean between the two races, but morally is inferior to either of them. Half-breeds have never made a society advance; the part they have played has been to degrade the civilizations of which they have by chance been the heirs. The disastrous results of such mixtures of superior races with inferior were clearly perceived by the most ancient civilized peoples. This was doubtless the origin of that rule of castes, preventing unions between persons of different races, which we find in many ancient societies. Without it, man would never have risen above the dawn of civilization.
But, while the mixture of races which have reached very unequal stages of evolution is always disastrous, the result is otherwise when these races, although still possessing different qualities, have arrived at nearly the same period of development. Their qualities can then very usefully complement one another. The republic of the United States has been formed by precisely such a mixture of races, already elevated in civilization and having qualities complementary to one another. The people owes its astonishing vigor to the fact not only that it is constituted of a mixture of elements—English, Irish, French, German, etc.—already highly developed, but also that the individuals through whom the crossing was effected were themselves the results of a selection from among the most active and vigorous members of those nations.
The general laws which we have just summarized can of themselves furnish the explanation of a large number of historical events.' They show, for example, why one conquest was the origin of a brilliant civilization, and why another introduced an era of disorder and anarchy; why the Oriental has always easily imposed his yoke and his customs upon Orientals whose mental constitution was like his own; and why struggles between Orientals and Westerners have been so ferocious, and usually terminated in pitiless massacres of the conquered. They likewise tell us why certain peoples have been colonizers, and how they have been able, naturally, if they were of the race of the conquered, or by respecting their customs and creeds if they were of a different stock, to maintain their authority over distant nations.
A question has arisen as to whether the steady advance of man tends to equalize races, or to differentiate them more and more. To it we have to answer that the upper level of civilization is always ascending; but by this fact itself, and since there are always nations at the lowest step, the gulf between them and the higher races is constantly growing deeper. There is progress, it is true, even in the most backward groups. But the law of this