Page:Popular Science Monthly Volume 5.djvu/83

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73
MEASURES OF MENTAL CAPACITY.

general measure of the position of a vertebrate species in the scale of cerebral and mental development. As a mere "general rule," to which, as is familiarly said, "there are always exceptions," it is certainly invulnerable, and is too valuable to be dispensed with. Hence, naturalists, while declaring it to be unreliable, have made a general application of it to the species of vertebrates, and to the races of mankind. Not only so—they have attempted to find out the definite grains of allowance in its application to particular cases, to discover the corresponding defects in the instrument, and to correct, improve, and perfect it. May it not be that the mistake is not so much in the facial angle as in the misunderstanding of its significance? If this can be shown, naturalists and ethnologists ought to make haste to receive the much-honored and much-abused facial angle into more hearty favor than ever.

But it will hardly do to proceed to this pleasant task before stopping to notice the proposition of the article entitled "The Facial Angle," in the March number of The Popular Science Monthly, to replace Camper's facial angle by another and better. The writer repudiates the angle of the frontal line with the base-line of the face, and proposes to supersede it by an angle of the frontal line with the axis of the body. He says, what everybody will admit, that the frontal line of the face is on a line with the axis of the body or spined column, in the lowest vertebrates, and that the two lines are parallel with each other in man. The absurdity of finding a facial angle, or any other angle, between two parallel lines, is evident at a glance. It might take two or three glances, but no more, to convince the ordinary mind that those two lines, with the cerebrum and cerebellum between them, cannot come in contact with each other, and can therefore form no angle between them, even in the lower animals. Disregarding the interposition of the brain, and extending the front line of the face and the axial line of the body, in imagination, until they meet, the intersected angle is not facial, and in the anthropoids it is so high in the air overhead as to be essentially visionary. Perhaps this is the reason why we have to look in vain at the only facial angles represented in the article referred to, Figs. 2 and 3, to find an illustration of the new facial angle proposed, concluding finally that they were intended to illustrate the old one. The truth is, supposing the brain to unite, instead of separate, the frontal line of the face and the axial line of the body, the bending of the continuous right line formed by them in the lowest vertebrate fishes into the two parallel lines in man, the one facio-abdominal and the other occipito-dorsal, is not by angles at all, but by curvatures, and the union of the parallels is by an arch over the head. The arc in each case is a greater or less part of a circle, according to the grade of intellectual and moral development. For example: In the typical man, the facial and dorsal lines, being parallel and perpendicular, are united at the top by a semicircle, very nearly