THE AMERICAN JOURNAL OF SOCIOLOGY
versed in anthropological technicalities, to offer some brief pre- liminary explanations. Europe is populated mainly by three racial groups, and by types in which two, or even three, of the racial strains blend, but which may nevertheless be regarded usually as belonging in preeminent degree to some one of the three primary races. These three races are designated by the terms, Homo Europceus (referred to also as the dolichocephalic blond, and sometimes, loosely, as the Aryan race); Homo Alpinus (referred to also as the brachycephalic, and sometimes, rather erroneously, as the "Celtic" or "Celta-Slav" race); and the so-called Mediterranean race (referred to also as the dolicho- cephalic brown or the southern dolichocephalic). These races may be distinguished, first, by their respective physical, and, secondly, by their respective psychological peculiarities. Homo Europ&us, in pure strain, is tall, light of skin, hair and eyes, long of face and head. Homo Alpinus is shorter, darker, and round- headed. The Mediterraneans have the long, narrow form of the head, but are prevailingly short, dark-skinned, dark-haired, dark- eyed ; hence their designation as the dolichocephalic brown race. For the purposes of the ethnical analysis of a given popula- tion it is desirable to find a single trait that will serve to identify a group of individuals with one or another race. Where, as in northern and western Europe, the population is mainly com- posed of the two first-mentioned races, the form of the head, as expressed by the cephalic index, serves as such a means of classi- fication and analysis. The cephalic index expresses the ratio of the breadth of the head to its length. It is found by dividing the breadth X 100 by the length. Thus, for example, a head measuring 189 millimeters in length by 150 in width would give a cephalic index of 79.8. Thus, low indexes indicate a dolicho- cephalic, and high indexes a brachycephalic population. 1
- In this article, for the sake of simplicity, the terms "dolichocephalic" and
brachycephalic" are employed simply as adjectives of description and comparison. In a more exact and technical sense they are sometimes employed as two terms in the seriation of indexes, thus : Indexes from 65 to 69, dolichocephalic ; from 70 to 74, sub-dolichocephalic ; from 75 to 79, mesacephalic ; from 80 to 84, sub-brachycephalic ; from 85 to 89, brachycephalic.
