For complete cataract nothing can be done. In man, operation or couching may be performed with success; but the horse can retract the eye and protrude the cartilago nictitans. Thereby difficulties are created; but these may be overcome. However, when an opening through the cornea is perfected, the spasmodic contraction of the muscles of the eye, acting upon the fibrous covering of the globe, is apt to drive forth the liquid contents of the organ in a jet: this is irreparable, of course. When so fearful a catastrophe does not ensue, still the capsule of the lens is always difficult to divide, and the lens itself cannot easily be broken down. The lens, therefore, must be abstracted; but that necessitates a large incision, which the previously named probability forbids. Displacement is the only resort left; but the lens, when forced from its situation into the posterior or dark cavity, is, by the contraction of the muscles, forced up again. The uncertainty of the result, even when the operation is successfully performed, is peculiarly disheartening. Half lose their eyes in consequence of the attempt; half the remainder are in no way benefited; to the rest, as these cannot wear spectacles to supply the place of the absent lens, of course the pain endured becomes useless torture. Where partial cataract is feared but cannot be detected, then artificially dilate the pupil. Rub down two drachms of the extract of belladonna in one ounce of water. Have this applied, with friction, to the exterior of the lids and about the eye; mind none gets into the eye. The belladonna, acted upon by the secretions, turns to grit; inflammation is the consequence, and the clearness of the cornea is impaired. When the belladonna is properly used, it dilates the iris and exposes the margin of the lens, thus enabling the practitioner to inspect the eye in a full light. [Illustration: DIAGRAM ILLUSTRATING THE ACTION OF BELLADONNA. The inner space represents the natural pupil, on which no cataract is to be observed. The second space represents the pupillary opening as it may be enlarged by the application of belladonna, whereon two partial cataracts are to be remarked. The other space merely represents the dilated pupil. ] To tell a spurious cataract, which defect is never permanent, first observe the spot. Note if it present any metallic appearance, and try whether, as the horse's head is moved, it alters in shape, catching irregular lights. Then inspect the exterior of the eye; see if it retain any signs of recent injury. Subsequently endeavor, so far as may be possible, to ascertain the exact position occupied by the defect: upon all this evidence put together, make up your opinion.