DISEASES OF THE EVE, ETC. 



347 



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 pro- 

 ducing a 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 nitrate of silver 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 generally 

 has to be repeated once more 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 bo 

 bathed with sulphate of zinc, 30 grains to half a pint of soft water, 

 several times a day, 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 

 circumstances the fungoid mass must be cut away, and the wound 

 cauterized with the nitrate of silver, or else the eye will soon bo 

 destroyed. When ulcers of the cornea appear indolent, with a tend 

 ency to slough, in addition to the treatment already prescribed, tonic 

 powders should be given twice a day mixed with the feed ; powdered 

 copperas, gentian, and ginger, equal parts by weight. Dose, ono 

 tablespoonful. 



STAPHYLOMA. 



This is a disease of the eyeball, in which the cornea loses its trans- 

 parency, rises above the level of the eye, and even projects beyond the 

 eyelids in the form of an elongated, whitish, or pearl-colored tumor, 

 which is sometimes smooth, at other times uneven. 



Causes.— Inflammation is the only known cause, although it may not 

 occur immediately; it frequently follows catarrhal conjunctivitis and 

 keratitis as a sequela. 



Treatment.— In a few cases restoration of sight may be effected by 



