Page:Popular Science Monthly Volume 50.djvu/785

Rh or eyes, the fallacy of direct comparison between the north and south of Europe again becomes apparent. In the third place, it is not easy to correct for the personal equation of different observers. A seeming brunette in Norway appears as quite blond in Italy because there is no fixed standard by which to judge. The natural impulse is to compare the individual with the general population round about. The precision of measurements upon the head is nowise attainable.

There are two principal modes of determining the pigmentation of a given population. One is to discover the proportion of so-called pure brunette types—that is to say, the percentage of individuals possessed of both dark eyes and hair. The other system is to study brunette traits without regard to their association in the same individual. This latter method is no respecter of persons. The population as a whole, and not the individual, is the unit. North of the Alps they have mapped the pigmentation in the main by types; in France, Norway, Italy, and the British Isles they have chosen to work by dissociated traits. Here again is a stumbling-block in the way of comparisons. The absolute figures for the same population gathered in these two ways will be widely different. Thus in Italy, while only about a quarter of the people are pure brunette types, nearly half of all the eyes and hair in the country are dark. That is to say, a large proportion of brunette traits are to-day found scattered broadcast without association one with another. In Europe, as a whole, upward of one half of the population is of a mixed type in this respect. In America the equilibrium is still further disturbed. Nor should we expect it to be otherwise. Intermixture, migration, the influences of environment, and chance variation have been long at work in Europe. The result has been to reduce the pure types, either of blonde or brunette, to an absolute minority. Fortunately for us, in despair at the prospect of reducing such variant systems to a common base, the results obtained all point in the same direction whichever mode of study is employed. In those populations where there is the greatest frequency of pure dark types there also is generally to be found the largest proportion of brunette traits lying about loose, so to speak. And where there are the highest percentages of these unattached traits, there is also the greatest prevalence of purely neutral tints, which are neither to be classed as blond or brunette. So that, as we have said, in whichever way the pigmentation is studied, the results in general are parallel, certainly at least so far as the deductions in this paper are concerned. Our map is indeed constructed in conformity with this assumption.