PRISM

n. Priazm. Gr., irpto-^ta (from irpi , to saw). Lat., prism a. Fr., prisme. Ger., Prisma. A solid the sides of which are parallelograms and its cro -section a figure of three or more sides, [a, 48.] Abducting p's. P's to be held before the eyes with their bases directed toward the nose, so as to cause divergence of th eyes. Adducting p's. P's to be held before the eyes with the bases outward, so as to adduct or converge the eyes in ophthalinological examinations. [H. Schmidt-Rimpler (A, 319).] Enamel p's. Fr., prismes de Is mail. Ger., Schmelzprismen, Schmelz fas ern. The solid hexagonal p's. about 0'015 millimetre in diameter, which, standing side by side, form the enamel of the teeth. Generally they are placed at right angles to the surface of the dentin. and are implanted in minute depre ions in it. Isolated p's, when viewed on the side, present a wavy outline, as if alternately constricted and enlarged. [J, 24. 30, 35.] Muscle p's. 1. See Sarcous ELEMENTS. 2. The dark discs of a muscular fibre. [J, 31.] E, he; E, ell; G, go; I, die; I2, in; N, in; N, tank: [s. 332]