Page:Popular Science Monthly Volume 5.djvu/85

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MEASURES OF MENTAL CAPACITY.
75

nostril to the occipital condyle, remains stationary. While the upper jaw maintains its fixed position, the lower jaw plays upon it; and so, while the base-line of the face in the upper jaw remains steadfast, the lines based and dependent upon it—the front facial line above, and the axial line below—are each effecting variations of 90° in relation to it, the one in relation to its anterior extremity and upper surface, and the other in relation to its posterior extremity and under surface, passing on the way through the angles represented in a b, Fig. 1, and ending as represented in a b, Fig. 2—the two variations together constituting

Fig. 1. Fig. 2.
Degrees of the Superior and Inferior Facial Angles.

the variation of 180°, or the half-orbit before mentioned. The base-line of the skull, so far from "varying irregularly," varies not at all, but is always straight, and in the most natural position of the head is always horizontal, while the frontal line of the face and the dorsal line of the body diverge more and more from the horizontal, and become more and more irregular in figure. The position of the head natural to social intercourse and to an outlook upon the horizon, as the general rule, is the one thing in which not only all men, but all vertebrate animals, are agreed, but they take infinite liberty to disagree in all other things, for the sake of showing the infinite diversity of individualities necessary to their harmonious interrelations and to the perfect individuality of the whole. When a man's "head is level," he is on a plane of equality, as a man and an animal, not only with his fellow-men, but with his fellow-creatures, and in a position to harmonize his differences with theirs. This horizontal position of the base-line of the face makes it the standard by which to compare the other lines, and by which to estimate the degrees of intelligence and affection as indicated by the degrees of the angles they make with it. When we consider how irregular in position and contour the spine and the features of the face become in the course of transition from the