PERIODIC OPUTilALMlA. 101 



employed. Mr. Cherry, the Principal Veterinary Surgeon to the 

 Cavalry, has used bichloride of mercury as a collyrium in the po- 

 tent form of solution in spirits of wine — 5J to the §j — and even 

 has touched eyes with the sublimate itself; and his note, in regard to 

 their effects, is — " it is of importance to remark how soon the very 

 considerable effect excited by the injection of corrosive subli- 

 mate in solution has subsided ; even the application of it in sub- 

 stance to the surface of the eye producing a scarcely perceptible 

 eiFect." By others, a rod of lunar caustic has been used. We 

 learn, indeed, both from practice and experiment, that our collyria, 

 to do good, have been in general applied in too weak a form : 

 Ave have not dared to do even what farriers before us did, and this 

 is one reason why our practice, in man}^ cases, has not turned out 

 so successful as theirs. After blood has been freely drawn, topi- 

 cally, and when the brunt of the disease is evidently confined to 

 the interior parts of the eyeball, the conjunctiva evincing but a 

 secondary or sympathetic sort of inflammation, I think we are 

 quite warranted in producing high counter-irritation in that mem- 

 brane ; and to effect this we shall find we must make use of 

 washes, or ointments, or powders, a great deal stronger than those 

 commonly used. At the same time I would introduce mercury 

 into the system as quickly as I could, compatible with safety, and 

 in some form or other establish counter-irritation; and when we 

 have done this, in my humble opinion, we have accomplished 

 somewhere about all that lies in our power by way of remedy for 

 an attack of periodic ophthalmia. 



In Chronic Ophthalmia, Mr. Dunn, V.S., is in the habit of 

 using with a good deal of advantage, as a topical application, an 

 unguent composed of chloride of mercury and honey or treacle. 



The Evacuation of the Aqueous Humour has, by Mr. 

 Wardrop, been highly lauded as a remedy for ophthalmia in man; 

 and I have often myself imagined that good might result from 

 such practice in the acute stages of periodic ophthalmia, though I 

 have never made trial of it. But there is a case on record, of 

 which the result would very much dispose us to test an operation 

 of the kind — one so simple that in proper hands it cannot well be 

 productive of any harm. This ''singular case" occurred to 



