11^ THE HORSE. 



been r jsortcd to for the purpose of removing this cloudiness. Chalk, and 

 salt, and suo-ar, and even pounded glass, have been introduced into the eye 

 mechanicull}' to rub off the film. It was forgotten that the cloudiness was 

 the efffct of inflammation, and that means so harsh and cruel were very 

 likely to recall the inflammation ; that these rough and sharp substances 

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

 is not a film on the surface of the cornea, but a dimness pervading its sub- 

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

 rubbed off. 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 corro- 

 sive sublimate, containing not more than a grain of sublimate to an ounce 

 of water. 



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 completely covers it. It is generally so white and pearly as not to 

 be mistaken : at other times more hazy, deceiving the inexperienced, and 

 occasioning doubt in the mind of the professional man. We have seen 

 maay instances in which the sight has been evidently affected or almost lost, 

 and yet a duferent opinion has been given by very fair judges. The eye 

 must be exposed to the light, and yet under the kind of shelter to which we 

 have previously referred, in order lo 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 which may be spreading over the lens. 



Cataract in ttie eye of a 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 

 operation ; 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 converged, 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 could not 

 adapt spectacles to the eye of the horse, or fix them there. 



GUTTA SERENA. 



Another species of blindness, and of which we spoke when describing 

 the retina, is Gutta Serena, commonly called the glass eye. The pupil is 

 more than usually dilated ; — it is immoveable, and bright and glassy. This 

 is the palsy of the optic nerve, or its expansion, the retina ; and is usually 

 produced by a determination of blood to the head. We have described it 

 as a consequence of staggers. So much pressure has been occasioned on 

 the base of the brain, that the nerve has been injured, and its function 

 destroyed. The treatment of Gutta Serena is quite as difficult as that of 

 cataract. We have heard of successful cases, but we never saw one ; nor 

 should we be disposed to incur much expense in endeavouring to accom- 

 ^iiisli impossibilities. Reasoning from the cause of the disease, we should 

 bleed, and physic, and rowel. If we succeed, it must be by constitutional 

 treatment; but in the majority of cases, the pressure would have long 

 ceased, although the mischief which it had effected remained. As to local 

 treatment, the seat of disease is out of our reach. 



