FIG. 16.—Japanese officer (old style), born at Tokio.
Example of elongated face.
(Phot. Coll. Mus. Nat. Hist., Paris.)
The measurements in a straight line are more numerous and more important than those of angles and curves. Those which give the antero-posterior diameter or maximum length of the head (from the glabella to the most prominent point of the occiput, as on the cranium) and the transverse maximum diameter, are the first to note. We have already seen (p. [57]) that their centesimal relation constitutes what is called the cephalic index. Let us note afterwards the total height of the head (projection on a vertical plane), the maximum breadth of the face (between the zygomatic arches) and the different “lengths” of the face, the relation of which to the breadth constitutes the facial index. The latter is far from expressing the form of the face as well as does the cephalic index the form of the head, on account of its irregularity, and the want of agreement between anthropologists with regard to the “facial lengths.” Nevertheless we distinguish according to these measurements elongated faces or leptoprosopic (Fig. [16]), short faces or chamæprosopic (Fig. [17]), and medium faces, meso- or ortho-prosopic (Fig. [14]).
FIG. 17.—Two men, Nagas of Manipur.
Examples of large faces with prominent cheek-bones.
(Phot. Miss Godden.)
Other measurements taken are the frontal minimum diameter or minimum breadth of the forehead (between the temporal ridges of the frontal bone, which makes a projection under the skin); the distance between the inner angles or canthus of the eyes is a good measurement, especially if it be compared with the breadth of the nose, taken by just touching with the points of the callipers the alæ of the nose. Referred to the length of the nose (between the root of the nose and the point of insertion of the septum) reduced to 100 it gives the nasal index, one of the important characters in the classification of races. Among several other measurements may be mentioned the breadth of the mouth between the commissure of the lips, the subject being in repose; the length and the breadth of the ears, etc. All these measurements are taken either with callipers or with sliding compasses, similar to those used by shoemakers or engineers, or with special instruments.[66]
Measurements taken on the living subject can never be as accurate as those obtained on the cranium; but, on the other hand, they may be much more numerous, and the greater number of observations compensates largely for individual errors due to difficulties of the mode of operation. Further, when measuring heads of living subjects, there is the advantage of knowing sex, approximate age, and exact origin, while in the case of one-half the crania examined, one or more of these particulars may be wanting. All these conditions sufficiently explain why, in these latter days, the attention of anthropologists is directed towards measurements of living subjects, among which those of the head occupy the foremost place.
Do the measurements of the head of the living subject correspond to the measurements of the cranium? Various researches made with the object of elucidating this question leave it still unsettled. It was believed at first, for instance, that the bregma, or point of junction between the coronal and the sagittal sutures in the cranium (Fig. [11], O), corresponded in the head with the most prominent point of the line passing from the supra-auricular point to another perpendicularly to the horizontal plane; but the very careful researches of Broca and Ferré have shown that this point is always in front of the bregma by a quantity which varies according to sex and individual. The correspondence of the tourbillon of the hair with the lambda, or point of junction on the cranium of the sagittal and occipital sutures (Fig. [11], F), has not either been clearly demonstrated. The principal measurement, the cephalic index, does not appear always to correspond on the cranium and on the head of the living subject. A priori, the living head should have the index a little higher than the cranium, the muscles of the temporal region being thicker than those of the supra-occipital and frontal region. However, experiments made in connection with this subject are contradictory. According to Broca, two units must be subtracted from the index taken on the living subject in order to obtain the index on the cranium; this is also the opinion of Stieda and Houzé and a great number of anthropologists, while Mantegazza and Weisbach advocate the reduction of the index by three units; and Virchow and Topinard do not admit any. In the face of these divergent opinions, it is best to give the indices on the cranium and the living subject separately as they are, and indicate the rate of reduction or augmentation.