However, in a general way, one may admit, and I admit in this book, the difference of two units between the indices of the cranium and the living subject. In this way the two may be compared by adding these two units to the index of crania and removing them from the index of the living subject. I have given (p. [57]) the divisions of the cephalic index of the cranium; those of the living subject are the same with the addition of two units.
We may now proceed to examine a little more closely the principal measurements and the indices on the living subject by beginning precisely with the cephalic index, which I believe to be, in spite of the recent criticisms of Sergi[67] and Ehrenreich,[68] one of the good characteristics of race, enabling us to make some secondary partitions in the principal partitions of the genus Homo, based, as we shall see afterwards ([Chapter VIII.]), on the colour of the skin and the nature of the hair. Assuredly this index cannot express by itself alone the true form of the head or the cranium, but it supplies very clearly a first indication which gives a much better idea than detailed description, useful, to be sure, but rendering the study almost impossible when it is a question of comparing with one another a great number of different types. On the other hand, this index has such a fixity within the limits of any given race, that it is difficult to conceive how it could be dispensed with. The figures given by different authors when they rest on a sufficient number of subjects agree so much among themselves as to the cephalic index, that it is impossible to deny its fixity. The recent researches of Gonner[69] on one hundred children of Basel, far from weakening the assertion, as it would appear, speak in its favour; made on only the new-born or children one month old, they confirm what was already known, that the cephalic index varies with age, and by no means contradict its fixity. Ordinarily, at birth children appear to be more dolichocephalic than the adults of their race, but from the first month the head grows faster in breadth than in length; thus at the end of the first month, according to Gonner, the head is broadened in 52 children in 100, and remains stationary in 9 per 100. My own researches lead me to believe that the heads of children increase at first in breadth, to arrive afterwards gradually at a definite form, which is fixed about the age of ten, twelve, or fifteen years, according to race.
If instead of comparing, as Gonner has done, children of one month old with their parents, he had taken children from ten years upwards, he would have arrived at the same results as Spalikowski, who on forty-eight infants at Rouen found forty-one of which the cranial form corresponded with their parents. The researches of O. Ammon, Johansson and Westermarck, Miss Fawcett and Pearson, as well as my own (yet unpublished), lead to the same result.[70]
The differences of the cephalic index according to sex are insignificant. According to my personal researches, this difference hardly exceeds on the average 0.7 in the living subject and 1.5 in the cranium; and even this latter figure is exaggerated. It may, in a general way, be admitted that the difference between the cephalic index of men and women hardly exceeds one unit—that is to say, the degree of personal error in the observation. This difference is, in any case, less than the discrepancies between the different series of a single and homogeneous race.
In the table of the cephalic index which appears at the end of this volume ([Appendix II].), however, I have given only the figures relating to men. A few series comprising individuals of both sexes appear there as exceptional cases. I have taken care to mark these with a letter S. In this table will be found side by side with indices taken on the living subjects some taken on crania, but no series contains measurements of crania and heads intermingled. The series of ten to twenty subjects or crania in the table appear there exceptionally, for the only series furnishing figures really exact are those comprising more than twenty individuals.
An inspection of the table shows us that there is a certain regularity in the distribution of the different cranial forms on the surface of the earth.
Dolichocephaly is almost exclusively located in Melanesia, in Australia, in India, and in Africa. Sub-dolichocephaly, diffused in the two extreme regions, North and South, of Europe, forms in Asia a zone round India (Indo-China, Anterior Asia, China, Japan, etc.), but is met with only sporadically in other parts of the world, especially in America. Mesocephaly is frequent in Europe in the regions bordering on the sub-dolichocephalic countries, as well as in different parts of Asia and America. Sub-brachycephaly, much diffused among the Mongolians of Asia and the populations of Eastern Europe, is very rare elsewhere. Lastly, brachycephalic and hyper-brachycephalic heads are almost exclusively limited to Western and Central Europe, to some populations of Asia, Turco-Mongols, Irano-Semites, and Thaï-Malays.
Has the form of the head, so far as the cephalic index can express it, an influence on the volume of the brain, and consequently on its weight, and even perhaps on the mentality? This question is subordinate to another, namely: To what point is the weight of the brain the expression of the psychical value of this organ? We shall see further, on p. [101], that the weight can only be considered as a very rough approximation for the solution of psychological questions. But even in recognising in the weight of the brain the exaggerated importance that too long has been attributed to it, it may be said that it is not in relation with the conformation of the skull. The only investigation made into this matter—that of Calori—restricted to the figures of adults (from 20 to 60 years) by Topinard,[71] shows us that among Italian men the brachycephalic have on an average 27 grammes of brain more than the dolichocephalic, while among Italian women it is the dolichocephalic who have the better of the brachycephalic by 21 grammes. The differences in the two shapes being so very trifling, one may consider one’s self equally intelligent whether dolichocephalic or brachycephalic.
Next to the form of the head, that of the face is of great importance in recognising races. It may be more or less long or broad, oval (Fig. [109]), ellipsoidal (Fig. [136]), or round (Figs. [119], [164], and [169]), with soft contours or very angular, and then it may be found as an elongated rectangle (Fig. [121]) or a square (Fig. [124]); it may approximate also to the pentagonal form (Fig. [17]), etc.
The forehead may be broad or narrow, low or high, retreating (oblique, Fig. [21]) or straight (Figs. [24] and [90]), it may present a medium protuberance, as for instance, among many Negro tribes (Fig. [140]), etc. The superciliary arches may be absent (Mongolian races) or very prominent, overhanging the eyes (Australians, Fig. [15]; Veddahs, Fig. [5]).