Ulcer of the Cornea. 387 



power of repair is -greatest. Finely powdered calomel or iodo- 

 form applied to the cornea will often prove effective. In case 

 potassium iodide has been given by the mouth, calomel or corro- 

 sive sublimate is liable to form mercurous or mercuric iodide 

 and cause ophthalmia. The same is true of iodoform if mercury 

 has been given internally. As a last resort tatQoing the spot has 

 been resorted to, to hide the opacity. 



UIvCER OF THE CORNEA. 



Infection of abrasions may cause ulcer. Age. House dogs-. Puppies on 

 vegetable food. Exhaustion. Starvation. Improper, insufficient diet. 

 Specific microbes and toxins. Symptoms : Ulcer with peripheral zone of 

 opacity. Photophobia. In marasmus little other local trouble. Diagnosis- 

 by oblique focal illumination or fluorescin. Granulation of Descemet's 

 membrane. Escape of aqueous. Keratitis. Panophthalmia. Staphyloma 

 Prognosis in debilitated, vigorous. Treatment : tonics, fresh air, good 

 food, sunshine, exercise, silver nitrate, mercuric chloride, iodoform, alcohol, 

 chlorine water, boric acid, cocaine, eserine, atropine, warm antiseptic com- 

 press, juice of fresh cassava. 



Causes. Wounds of the cornea, making an infection entrance 

 for pus microbes, are liable to lead to ulceration, and a corres- 

 ponding destruction of the epithelium and superficial layers by 

 inflammation, may start a similar ulcerative process. Apart from 

 these conditions, ulceration is especially liable to occur in very 

 old dogs, in closely confined house dogs, in puppies raised on an 

 exclusive diet of vegetable food, and in animals worn out by 

 disease, exhaustion, starvation, or improper and insufficient diet. 

 Majendie's dogs fed on sugar, starch and other imperfect .diet, 

 suffered in this way. Finally, the local action of certain specific 

 disease poisons, enzootic purulent ophthalmia, canine distemper, 

 dogpox (Trasbot), equine influenza (Schindelka), sheep-pox, 

 and blennorrhcea (MoUer), leads to ulceration. 



Symptoms. In keratitis there is usually a marked local opacity 

 in the centre of which the breach of the surface may be found. 

 The attendant photophobia with closure of the lids and pupil is 

 strongly suggestive of ulcer. In the specific diseases, the local 

 inflammation, the rapid progress of the lesion and the coexist- 



