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Show 298 FEAR. CHAP. XII. which slope backwards, are raised in opposite directions by the contraction of the occipito-frontalis or scalp muscle. So that this muscle seems to aid in the erection of the hairs on the head of man, in the same manner as the homologous panniculus carnosus aids, or takes the greater part, in the erection of the spines on the backs of some of the lower animals. Contraction of the platysma myoides muscle.-This muscle is spread over the sides of the neck, extending downwards to a little beneath the collar-bones, and upwards to the lower part of the cheeks. A portion, called the risorius, is represented in the woodcut (M) fig. 2. The contraction of this muscle draws the corners of the mouth and the lower parts of the cheeks downwards and backwards. It produces at the same time divergent, longitudinal, prominent ridges on the sides of the neck in the young; and, in old thin persons, fine transverse wrinkles. This muscle is sometimes said not to be under the control of the will; Lut almost every one, if told to draw the corners of his mouth backwards and downwards with great force, brings it into action. I have, however, heard of a man who can voluntarily act on it only on one side of his neck. Sir C. Bell 21 and others have stated that this muscle is strongly contracted under the influence of fear; and Duchenne insists so strongly on its importance in the expression of this emotion, that he calls it the muscle of fright. 22 He admits, however, that its eontraction is quite inexpressive unless assoC'iated with widely open eyes and mouth. He has given a pho- 21 'Anatomy of Expression,' p. 168. 22 Mecanisme de la Pbys. Humaine, Album, Legende xi. CHAP. XII. CONTRAC'l'ION OF THE PLATYSMA. 299 tograph ( copi d and r duced in the a ompanying woodcut) of the an1e old man as on form r occnions, with hi ey brows trono-ly rai d, hiR mouth opened, and the platy rna contracted, all by m an Fig. 20. Terror. From a photograph by Dr. J)ucb nne. of galvanism. The original photograph was shown to tw nty-four p rsons, and th y were sflparately ask d, with ut any xplanation b ing given, what expr o:sion was intended : twe11ty instantly answered, "intense |