main ethnic types that go to make up the Occidental populations. The individuals in these communities are conceived to be, in virtually every instance, hybrids of the prevailing ethnic elements combined in the most varied proportions; with the result that they tend to take back to one or the other of the component ethnic types. These ethnic types differ in temperament in a way somewhat similar to the difference between the predatory and the ante-predatory variants of the types; the dolicho-blond type showing more of the characteristics of the predatory temperament—or at least more of the violent disposition—than the brachycephalic-brunette type, and especially more than the Mediterranean. When the growth of institutions or of the effective sentiment of a given community shows a divergence from the predatory human nature, therefore, it is impossible to say with certainty that such a divergence indicates a reversion to the ante-predatory variant. It may be due to an increasing dominance of the one or the other of the "lower" ethnic elements in the population. Still, although the evidence is not as conclusive as might be desired, there are indications that the variations in the effective temperament of modern communities is not altogether due to a selection between stable ethnic types. It seems to be to some appreciable extent a selection between the predatory and the peaceable variants of the several types.
This conception of contemporary human evolution is not indispensable to the discussion. The general conclusions reached by the use of these concepts of selective adaptation would remain substantially true if the
