DISEASES OF THE EYE. 385 



tnulated urine and dung. But these would produce no such effect 

 in a horse, unless he were predisposed to ophthalmia; and we find 

 that cattle and sheep are often fed to an enormous degree of obe- 

 sity, in far closer and worse ventilated stalls, without any prejudi- 

 cial effect upon their eyes. It may, then, be assumed, that these 

 organs in a horse have a tendency to put on inflammation ; but 

 though these words are true they explain nothing of the real cause, 

 and only serve to conceal our ignorance of it. There is another 

 question bearing upon this subject, which is of the highest import- 

 ance. Is the stock of blind horses more liable to blindness than 

 that of sound ones ? This has been discussed so often, that it is 

 scarcely possible to throw any fresh light upon it, chiefly because 

 it is so difficult to rely upon the facts adduced pro and con. Blind- 

 ness is often the result of accident, and such cases are believed to be 

 exceptional, and not at all likely to hand down the disease ; but, on 

 the contrary, I am inclined to believe that many of them show a 

 marked tendency to its development; for an accident never destroys 

 both eyes, and when one follows the other, it is a pretty sure sign that 

 there is a tendency to ophthalmia. On the whole, it may, I think, be 

 assumed, that the tendency to specific ophthalmia is handed down 

 from generation to generation, and, consequently, that the offspring 

 of a horse who has gone blind from that cause is peculiarly prone 

 to it. Its symptoms appear very rapidly, fhe eye having been 

 quite right over night, looks contracted and almost closed next 

 morning, and on inspecting it closely " the white" looks of a deep 

 red, the cornea looks muddy, and the colored part of the eye (the 

 iris) has lost its bright color, and often shows one or two white specks 

 upon it (these must not be confounded with specks on the cornea). 

 As the disease advances, the intolerance of light is very great, the 

 cornea and iris become gradually more muddy, and either lymph 

 is thrown out on the latter in the shape of white patches, or pus 

 is secreted and fills the chamber of the aqueous humor, in part or 

 wholly. If the treatment is sufficiently energetic, these signs 

 abate, the pus or lymph is absorbed, and the eye recovers its trans- 

 parency ; but there are generally some traces left behind. Bleed- 

 ing (either from the jugular or the angular veins of the face), 

 moderate purging, and a seton, are the remedies best calculated to 

 effect this object, conjoined with an airy stable and a light diet. 

 Unfortunately, however, iritis is almost sure to return on the 

 restoration of the usual food, and exposure to the elements ; and 

 hence it is of the utmost consequence in purchasing a horse to 

 examine his eyes for the marks left behind by it. If the case is 

 hopeless, it becomes a question whether or not it will be wise to 

 put an end to the inflammation by destroying the affected eye, for 

 it is well known that if it goes on for any length of time the other, 

 sound eye, becomes affected. The only difficulty consists in feel- 

 33 2B 



