Races of Mankind

RACES OF MANKIND. The study of the varieties of the human race has occupied the attention of thinkers from early times. Two entirely different forms of classification have been employed, one based on the study of the skull, the second, and more generally used method, on superficial characters, such as skin and hair, which may be observed on the living man. To some extent these two methods have been combined in modern times.

Cranial Form.

Apart from Sergi, who elaborated a method of classification based on cranial form, the shape being estimated by viewing the skull from on top, most anthropologists have pre f erred to take measurements, especial importance being attached to the cephalic index—the percentage ratio of the length to the breadth—but numerous other measurements have been made, mostly of little value for classification. W. L. H. Duckworth sug gested the combination of three characters on the skull, the cranial capacity, the cephalic index and the degree of prognathism (measured by taking the angle which the most projecting part of the jaw makes with the forehead). On the basis of the possible combinations of these criteria Duckworth divided mankind into seven groups.

Coefficient Method.

Karl Pearson devised a method, termed the coefficient of racial likeness, which aims by a method of averaging at including a very large number of measurements in a single figure. The method is complex, and depends on the differ ence between a series of measurements taken on a set of skulls belonging to one race, and those taken on a second set. There is less difference in those closely allied than in those more distantly related, and the coefficient is correspondingly smaller or bigger. The rather complex mathematical processes involved are the chief disadvantage of the coefficient method.

Colour

Groups.—The oldest grouping of mankind, still in popular use, is that of skin colour. It has been suggested that the degrees in pigmentation of the human skin are due to the effects of environment, either to sunlight or humidity or a com bination of both, the evolutionary changes which took place at an earlier date having become part of the heritage of the races we know to-day. Although the darkest skins are to be found in

the tropics, whereas the fairest occur in the temperate climate of western Europe, attempts to correlate skin colour and environ ment break down when specific cases are considered. Some ex ceptions can be explained by recent immigration, others again, especially in the individual, by racial admixture, for where races are mixed we may find members of the same family who are very differently pigmented. On the whole the average value of the skin colour in various groups is correlated with other criteria, which appear to be good bases for classification.

One of the most important of these is the cephalic index. Taking the length as too, the proportion of the breadth seldom falls below 7o or over 90, and it is usual to describe those peoples with an index below 75 as dolichocephalic (long-headed), those above 8o as brachycephalic (short-headed), the intermediate group being mesocephalic. Taken by itself, either in the individual or the race, the cephalic index is by no means a certain guide. We find brachycephalic, mesocephalic and dolichocephalic groups in all the greater divisions of mankind. In the individual, a series of 6,000 Japanese contained one man with an index of 69, and one of 96, and in a continuous series between these two extremes over 700 (about 12%) having indices between 8o and 81, the average being just under the latter figure.

Of the characters generally in use, however, the cephalic index shows most consistently the lowest relative variation within small groups. It is therefore of great value for classifying smaller units within the wider divisions, but deductions can only be drawn from the average of a reasonably large number of individuals, at least 5o of the same sex. The practice of artificial deformation may to a certain extent obscure the true head form, and where it occurs the cephalic index is often of little value.