DISEASES OF THE EYE, 347 



To remove opacity, after the inflammation has subsided, apply a 

 few drops of the following solution twice a day: lodid of potas- 

 sium, 15 grains; tincture sanguinaria, 20 drops; distilled water, 2 

 ounces; mix. 



Sometimes keratitis exists in a herd as a transmissible disease, 

 spreading like infectious conjunctivitis. Calomel, applied to the eye, 

 is especially useful in such cases. 



ULCERS OF THE CORNEA. 



An ulcer comes from erosion or is the consequence of the bursting 

 of a small abscess, which may have formed beneath the delicate layer 

 of the conjunctiva, continued over the cornea; or, in the very sub- 

 stance of the cornea itself, after violent keratitis, or catarrhal con- 

 junctivitis. At other times it is produced by bruises, scratches, or 

 other direct injury of the cornea. 



Symptoms. — The ulcer is generally at first of a pale gray color, 

 with its edges high and irregular, discharges instead of pus an acrid, 

 watery substance, and has a tendency to spread widely and deeply. 

 If it spreads superficially upon the cornea, the transparency of this 

 membrane is lost; if it proceeds deeply and penetrates the anterior 

 chamber of the aqueous humor, this fluid escapes, the iris may pro- 

 lapse, and the lens and the vitreous humor become expelled, thus 

 producing destruction of the whole organ. 



Treatment. — It is of the greatest importance, as soon as an ulcer 

 appears upon the cornea, to prevent its growing larger. The corrod- 

 ing process must be converted into a healthy one. For this purpose 

 nothing is more reliable than the use of solid nitrate of silver. A 

 stick of this medicine should be scraped to a point; the animal's 

 head should be firmly secured; an assistant should part the lids; if 

 necessary, the haw must be secured within the corner of the eye and 

 then all parts of the ulcer should be lightly touched with the silver. 

 After waiting a few minutes the eye should be thoroughly washed 

 out with a very weak solution of common salt. This operation gen- 

 erally has to be repeated at the end of three or four days. If healthy 

 action succeeds, the ulcer assumes a delicate fleshy tint, and the 

 former redness around the ulcer disappears in proportion as the ulcer 

 heals. 



In superficial abrasions of the cornea, where there is no distinct 

 excavation, this caustic treatment is not needed. The eye should be 

 bathed several times a day with sulphate of zinc, 30 grains to half a 

 pint of soft water, and protected against exposure to cold air and 

 sunlight. Excessive ulceration sometimes assumes the form of fun- 

 gous excrescence upon the cornea, appearing to derive its nourish- 

 ment from loops of blood vessels of the conjunctiva. Under these 



