116 THE HORSE. 



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

 salt, and sugar, and even pounded glass, have been introduced into the eye 

 mechanically to rub ofFtbe film. It was forgotten that the cloudiness was 

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

 hkely 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 corrosive sublimate, containing not more than a grain of the 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 

 many instances in which the sight has been evidently affected or almost 

 lost, and yet a different 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 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 which may be spreading 

 over the lens. 



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 

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

 usually produced by determination of blood to the head. We have de- 

 scribed it as a consequence of stagoers. So much pressure has been oc- 

 casioned 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- 

 plish impossibilities. Reasoning from the cause of the disease, we should bleed 

 and physic, and rowel. If we succeeded, it must be by constitutional treat- 

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

 although the mischief which it had effected remained. As to local treat- 

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



