166 SPECIFIC OPHTHALMIA. 



The most frequent consequences of this disease are cloudiness of the eye, 

 and cataract. The cloudiness is singular in its nature. It will change in 

 twenty-four hours from the thinnest film to the thickest opacity, and, as sud- 

 denly, the eye will nearly regain its perfect transparency, but only to lose it, 

 and as rapidly, a second time. 



The most barbarous methods have been resorted to for the purpose of remov- 

 ing this cloudiness. Chalk, and salt, and sugar, and even pounded glass, have 

 been introduced into the eye mechanically to rub off the film. It was forgotten 

 that the cloudiness was the effect of inflammation that means so harsh and 

 cruel were very likely to recall that inflammation that these rough and sharp 

 substances must of necessity inflict excruciating pain ; and that, after all, it 

 generally was not a film on the surface of the cornea, but a dimness pervading its 

 substance, and even sinking deep within it, and therefore not capable of being 

 removed. Where the cloudiness can be removed, it will be best effected by 

 first abating inflammation, and then exciting the absorbents to take up the 

 grey deposit, by washing the eye with a very weak solution of corrosive 

 sublimate. 



Opacity of the lens is another consequence of inflammation. A white speck 

 appears on the centre of the lens, which gradually spreads over it, and com- 

 pletely covers it. It is generally so white and pearly as not to be mistaken 

 at other times it is more hazy, deceiving the inexperienced, and occasioning doubt 

 in the mind of the professional man. We have seen many instances in which 

 the sight has been considerably affected or almost lost, and yet the horse has been 

 pronounced sound by very fair judges. The eye must be exposed to the light, 

 and yet under the kind of shelter which has been already described, in order to 

 discover the defect. The pupil of the horse is seldom black, like that of the 

 human being, and its greyish hue conceals the recent or thin film that may be 

 spreading over the lens. 



Confirmed cataract in the eye of the horse admits of no remedy, for two 

 obvious reasons : the retractor muscle draws the eye back so powerfully and so 

 deeply into the socket that it would be almost impossible to perform any opera- 

 tion ; and, could an operation be performed, and the opaque lens removed, the 

 sight would be so imperfect, from the rays of light not being sufficiently con- 

 verged, that the horse would be worse to us than a blind one. The man who 

 has undergone the operation of couching may put a new lens before his eye, in 

 the form of a convex spectacle ; but we cannot adapt spectacles to the eye 

 of the horse, or fix them there. 



Since the publication of the first edition of the " The Horse," some contro- 

 versy has taken place with regard to the occasional appearance and disappear- 

 ance of cataract without any connexion with the common moon-blindness. 

 Mr. Clay deposed in evidence, that cataracts might be formed in a fortnight 

 or three weeks that he had known many instances in which they had been 

 completed in less time, and without any previous apparent disease of the eyes ; 

 and that he had detected them when the owners had not the slightest suspicion 

 of disease in the eye*. 



Mr. Cartwright adds, that he has known two similar cases. The first was 

 of a horse that had two cataracts in each eye two of them of the size of a large 

 pin's head, and the other two treble that size. There was no vestige of former 

 inflammation ; and the person who bred him said that he never had been sub- 

 ject to inflammation of the eye. In December 1831, these cataracts were 

 plain enough ; but in the autumn of 1832 they had completely vanished. 



In November 1832, Mr. Cartwright saw a five-years old mare, and detected 



* Vetcrinariau, vol. vii. p. 41. 



