2G4 INDUCTION OF NEBULOUS CORNEA, &C. 
When a clear case of chronic ophthalmia is brought before you, 
do not hesitate at once to blow into the eye, by means of a small 
canula or a quill, the red nitrate of mercury. What I have been 
in the habit of using is equal parts of alumen ustum and the red 
oxide. It acts better when combined than single, most likely from 
the alum constringing the conjunctival membrane, and thus con- 
fining the particles of the nitrate. However, this compound blown 
into the eye quickly produces intense discharge; the eyelids ra- 
pidly tumefy, become closed, and the discharge continues for a 
week or ten days. On inspecting the eye after its subsidence, 
I have found it completely restored, to the satisfaction of myself 
and owner. I generally order, during the discharge, a strong 
decoction of poppy, used as a fomentation, which promotes the 
secretion, keeps the parts clean, and prevents excoriation of the 
cheeks. 
I shall now speak of the various forms of cataract I have re- 
lieved. Horses deemed useless have been made useful by adopt- 
ing the plan of conjunctival irritation. The forms best suited for 
this treatment are those termed the lymph cataract, vitreous ca- 
taract, milky cataract, capsular and caseous cataracts. For the relief 
and cure of any of these forms of disease, counter-irritation of 
the conjunctival membrane must be kept up some time. When 
the first irritation has ceased, even a second or third must be ex- 
cited. On the true lenticular or crystalline cataract I have not as 
yet made a fair trial, but have not the least doubt that a great 
many of the numerous forms of cataract may be absorbed, and the 
animals rendered of service, by following this plan of counter-irri- 
tation. We have all of , us, perhaps, heard of or seen cataracts 
spontaneously absorbed : such being the fact, I do not see why 
their absorption may not be artificially promoted in the chronic or 
subacute ophthalmia, a sequel of the acute. 
Mr. Percivall, I think, recommends the administration of mer- 
cury, so as to affect the system. I have again and again tried 
mercury, but to no purpose : doses of only half a drachm have in- 
duced superpurgation. The only conclusion I can draw is this, 
that our horses in the country live on food very sparingly azotized, 
or charged with albumen, consequently their secretions are more 
active and are more easily excited by mercury ; while horses in 
cities or barracks live chiefly on food highly nitrogenized, and 
their secretions are not so active, bear the introduction of mercury, 
and are not so readily affected by its internal administration. I 
have now brought this paper to a close, and trust that it may 
answer the expectations of those who deem it worth a trial. 
