IMAGE

n. Pm'aj. Gr., eliuov. Lat., imago. Fr., i. Ger., Bild. An optical or mental representation of a body. Accidental i. See After -i. Actual ophthalmoscopic-i. Fr., i. actuelle ophthalmoscopique. Ger., virtuelles ophthalmoscopisches Bild (oder Augenspiegelbild). See Indirect IMAGE. Aerial i. 1'he i. of an object when it appears suspended in the air. [L, 108.] After-i. An i. perceived by the retina after the exciting stimulus has been withdrawn. When these images are simply continuations of the sensation they are known as positive a.-i's; when they are of a complementary color they are known as negative a.-i's. [F, 25; L, 253 (a, 29).] Catoptric i's. I's reflected from polished surfaces, [a, 29.] Consecutive i's. I's which follow one another in regular succe ion, fa, 29.] Cro ed i's. Fr., i's croisees.' Ger., gekreuzte Doppelbilder. I's of objects existing in cro ed diplopia, due to divergence of the visual axes. [F.] Demi-i. (Fr.). See Half-L Diffusion i's. I's formed by rays of light from an object pa ing through a lens and falling upon a surface not at the focus, [a, 29.] Erect i. See Upright i. Half-i. Fr.,dem i-i. Ger., Halb-Bild. Of Helmholtz, one of the two double i's. cast by the same object, but not seen singly by the two eyes. [F.] Homonymous i's. Fr., i's homonymes. Ger., gteichnamige Bilder. Those double i's occurring on the side corresponding to the eyes; the right i. is corresponding to the right eye, and the left i. to the left eye. This form of diplopia is caused by convergence of the visual axes. [F.] I's croisees (Fr.). See Cro ed i's. I's hymonymes (Fr.). See Homonymous i's. I. renversee. See Inverted i. I. virtuelle. See Virtual i. Indirect i., Inverted i. Fr, i. renversee. Ger., umgekehrtes Bild. A real, magnified i. of the fundus of an eye, in which the emerging rays are focused by means of a convex gla before entering the eye of the observer. [F.] Multiple i's. Fr., i's multiples. Ger., vielfache Bilder. It., imagini multipli. Sp., imdgenes multdplices. See under POLYOPIA. - Real i. Fr., i. reelle. An i. formed by the convergence of reflected or refracted rays after their emergence from the reflecting source or the refracting medium; so called because actually existing at the spot at which it is seen, and capable of being thrown upon a screen placed at this spot. The i's formed by concave mirrors or concave lenses and the inverted ophthalmoscopic i. are real. [B.] Retinal i. Fr., i. retinien. The i. formed upon the retina by rays of light which pa from an external object through the dioptric mechanism of the eye. [a, 29.] Stereoscopic i. Fr., i. stereo scop i que. Ger., stereoskopisches Bild. The i. produced on the retina of the two eyes by uniting stereoscopically the i. of two photographs taken from one and the same negative. This gives an undeniable impre ion of solidity, although it is simply an optical illusion. [F.] Upright i. Fr., i. droite. Ger., aufrechtes Bild. An enlarged i. of the fundus of the eye, seen with the ophthalmoscope by aid of the dioptric apparatus of the eye, without the interposition of a bi-convex lens. [F.] Virtual i. Fr., i. virtuelle. Ger., virtuelles Bild. An i. formed by the prolongation of reflected or refracted rays back behind the reflecting surface or the refracting medium; so called because not actually existing at the spot at which it appears. The i. in a looking-gla , the i's formed by concave lenses and convex mirrors, and the ophthalmoscopic i. are examples. [B.] [s. 437]