998 DISEASES AND THEIE TEEATMENT. 



Cataract 



Is the name applied to a deposition of a pearly white substance 

 within the eye, and is a very common affection in this country. 

 It consists in an effusion of lymph, either on the middle humor 

 (crystalline lens), or on its capsule, and is variable in size, some- 

 times not larger than the head of a pin, while in other cases it 

 covers the whole lens. 



Causes. — It is generally a result of repeated attacks of specific 

 ophthalmia, or it may even supervene upon a first attack; it may 

 follow a severe injury to the eye. 



Symptoms. — The eyesight is either partially or completely 

 gone, and when covering the greater part of the lens, it is easily 

 known by its pearly white appearance. "When small, it is some- 

 what difiicult of detection ; the eye is smaller than in health, and 

 the pupil becomes greatly contracted when exposed to light. It 

 may be detected by placing the animal in a bright light, and care- 

 fully examining the eye; if the eye appears smaller than the 

 other, it indicates something amiss with it. He should then be 

 placed in a darkened stable, and allowed to stand quietly for ten 

 or fifteen minutes before being subjected to an examination. Stand 

 in front of him, and bring a lighted candle close up to the front 

 of his eye, when any alteration in the structure of the lens can be 

 readily detected. 



Treatment on the horse is useless, as when permanently es- 

 tablished, it cannot be removed. When the cataract is confined 

 to one eye only, it interferes but little with the horse's usefulness 

 for ordinary work. 



The cornea is frequently injured from the puncture of a nail, 

 allowing the aqueous humor to escape, and perhaps injuring the 

 crystalline lens, completely destroying vision. When the injury 

 is confined to the cornea, the humor may be reproduced. The 

 part should be diligently bathed, either with hot or cold water, and 

 the fomentations must be applied several times a day; and the eye 

 supported by means of a wet sponge or cloth, which tends to sub- 

 due the acute inflammation and allay the pain, and by keeping 

 the eyelids closed, it supports the lacerated parts. 



After a few days it may be necessary to stimulate the part, 



