118 SPECIFIC OPHTHALMIA. / 



parency — even the iris changes its colour, and the pupil is e.\Li KUi.gly contTacted 

 The veterinary surgeon has now an obstinate disease to comhat, and one that will 

 generally maintain its ground in spite of all his efforts. For three, or four, or five 

 weeks, the inllaniniaticn will remain undiminished ; or if it appears to yield on one 

 day. it will return with redoubled violence on the next. At length, and often uncon- 

 nected with any of the means that have been used, the eye begins to bear the lio-nt, 

 the redness of the membrane of the lid disappears, the cornea clears up, and the only 

 vestige of disease which rem.ains is a slight thickening of the lids and apparent un- 

 easiness when exposed to a very strong light. 



If the owner imagines that he has got rid of the disease, he will be sadly disap- 

 pointed, for, in the course of six weeks or two months, either the same eye under- 

 goes a second and similar attack, or the other one becomes affected. All again 

 seems to pass over, except that the eyy is not so perfectly restored, and a slight, 

 deeply-seated cloudiness begins to appear; and after repeated attacks, and alterna- 

 tions of disease from eye to eye, the affair terminates in opacity of the lens or its cap- 

 sule, attended with perfect blindness either of one eye or both. This affection was 

 formerly known by the name of moon-blindness, from its periodical return, and some 

 supposed influence cf the moon. That body, however, has not, and cannot have any- 

 tliing to do with it. 



What is the practitioner doing all this while ] He is an anxious and busy, but 

 almost powerless spectator. He foments the eyes with warm water, or applies cold 

 lotions with the extract of lead or opium, or poultices to which these drugs may be 

 added ; he bleeds, not from the temporal artery, for that does not supply the orbit of 

 the eye, but from the iniiitilur vein at the inner corner of the eye, or he scarifies the 

 lining of the lid, or subtracts a considerable quantity of blood from the jugular 

 vein. The scarifying of the conjunctiva, which may be easily accomplished with- 

 out a twitch, by exposing the inside of the lids, and drawing a keen lancet slightly 

 . over them, is the most effectual of all ways to abate inflammation, for we are then 

 iimnediately unloading the distended vessels. He places his setons in the cheek, 

 cr his rowels under the jaw ; and he keeps tlie animal low, and gives physic or 

 fever medicine (digitalis, nitre, and emetic tartar.) The disease, however, ebbs and 

 Hows, retreats and attacks, until it reaches its natural termination, blindness of one 

 or both eyes. 



The horse is more subject to this disease from the age of four to six years than 

 at any other period. He has then completed his growth. He is full of blood, and 

 liable to inflammatory complaints, and the eye is the organ attacked from a peculiar 

 ]>redisposition in it to Inflammation, the nature or cause of which cannot always be 

 explained. Every afiection of the eye appearing about this age must be regarded 

 with much suspicion. 



It is a common ojdnion that black horses are more subject to blindness than others. 

 There is considerable doubt about this, or rather it is probable that that colour has no 

 influence either in producing or aggravating the disease. 



As this malady so frequently destroys the sight, and there are certain periods when 

 the inflannnation has seemingly subsided and the inexperienced person would be 

 deceived into the belief that all danger is at an end, the eye should be most carefully 

 observed at the time of purchase, and the examiner should be fully aware of all the minute 

 indications of previous or approaching disease. They are a slight thickening of the 

 lids, or puckerimi towards the inner corner of the eye; a differei:ce in the apparent 

 size of tlie eyes; a cloudiness, although jxrhaps scarcely perceptible, of the surface 

 of the cornea, or more deeply sealed, or a hazj' circle round its edge; a gloominess 

 of eye generally, and dulncss of the iris; or a minute, faint, dusky spot in the cen- 

 tre, with or without minute fibres or lines diverging from it. 



The cause of this inflammation is undoulitedly a strong predisposition to it in the eye 

 of the horse, but assist(-d by the heated and empoisonid air of niany stables. The 

 heated air has much to do \\ ilh the production of the disease; the empois(inrd air a 

 great deal more: for every one must haA'e obseived, on entering a close stable early 

 in the morning, str^nu" liimes of hartshorn whicli were iiainful to his eyes and caused 

 the tears to flow. What must be the constant action of this on the eyes of the horse 1 

 The dwng of the horse, and the litter of the stables, when becoming prlnd, emit 



