96 PERIODIC OPHTHALMIA. 



stables would escape in situations in the open air; and that in 

 stables we find the proportion of cases less according as the animal, 

 at this trying time of his life, from his fourth to his fifth year, is 

 moderately fed, moderately worked, and kept in an atmosphere 

 unheated and uncontaminated. I believe that almost any thing 

 that will excite commotion in the system at this critical period of 

 age is likely to shew itself in the eyes — though not so likely as it is 

 to take effect upon the membrane lining the air-passages. Most 

 young horses, on being stabled, become affected by some catarrhal 

 or bronchitic disorder: some have swelled legs, or fly at the heels; 

 some few get strangles; one, here and there, may evince some 

 diarrhoeal affection ; others will have periodic ophthalmia ; and it 

 is common for attacks of these diseases — in particular of ophthal- 

 mia — to come on during the night, at the time when the miasm 

 of the atmosphere of the stable may be supposed to have attained 

 its most concentrated and active form. 



Is THE Disease local or constitutional? Most decidedly 

 constitutional. Not a simple conjunctival affection, although the 

 conjunctiva is a participant in it; but, essentially and primarily, a 

 disease of the internal structures of the eye. How these struc- 

 tures become affected by the causes which are said or thought to 

 give origin to the disease, I do not pretend to say : all I dare ven- 

 ture upon is an opinion, that the blood is the medium of contami- 

 nation. It would be worth while to transfuse the blood of the op- 

 thalmic subject into healthy veins, Avith a view of ascertaining 

 whether the disease were communicable in this manner. I cannot 

 help imagining, myself, some analogy — in causation at least — be- 

 tween this disease and glanders and farcy ; and in the latter we 

 know that the blood is infected. In fine, altogether, I am more of 

 a Colemanite in my opinions than any thing else ; still, not com- 

 pletely so. 



The Treatment of a disease, concerning whose nature the 

 medical practitioner feels compelled to confess a good deal of igno- 

 rance, is not likely to turn out very satisfactory ; and this happens 

 to be one of those diseases in the treatment of which, while the 

 result is such as is almost certain to deceive the owner of the horse, 



