526 THE HORSE. 
they cannot fail to perceive the disease. When cataract is clearly proved 
to exist, all idea of treatment may be abandoned, as nothing but an 
operation can procure a removal of the opacity ; and that would leave the 
horse in a more useless condition than before, since he could see nothing 
clearly, and would only be subject to continual alarms. In the human 
being, the operation is performed with great success, because the lens 
which is sacrificed can be replaced externally by means of convex glasses; 
but in the horse, nothing of the kind can be done. Hence, it is useless 
to dream of effecting any improvement in this disease ; and if both eyes 
are the subject of cataract, the horse is incurably blind. But supposing 
there is a cataract in one eye only, is the other sure to go blind, or may a 
reasonable hope be entertained of its remaining sound? Here the history 
of the disease must be examined before any opinion can be formed. If 
the opacity followed an accident, there is no reason for concluding that the 
other eye will become diseased ; but if it came on idiopathically, either 
preceded by inflammation or otherwise, there is great risk of a repetition 
in the sound eye. Nevertheless, instances are common enough of one eye 
going blind from cataract, while the other remains sound to the end of 
life ; and those are still more frequent in which the one sound eye con- 
<inues so for six or seven years. 
AMAUROSIS. 
THIS 1s A PALSY of the nervous expansion called the retina, produced by 
some disease, either functional or organic, of the optic nerve, which is 
generally beyond the reach of our senses, in examining it after death. 
The symptoms are a full dilatation of the pupil, so that the iris is shrunk 
to a thin band around it, and is so insensible to the stimulus of light, in 
confirmed cases, that, even when the eye is exposed to the direct rays of 
the sun, it does not contract. In the early stages, this insensibility is 
only partial ; and though there is such complete blindness that the horse 
cannot distinguish the nature of surrounding objects, yet the pupil con- 
tracts slightly, and the inexperienced examiner might pass the eye as a 
sound one. The unnaturally large pupil, however, should always create 
suspicion ; and when, on closing the lids and re-opening them in a strong 
light, there is little or no variation in its size, the nature of the disease is 
at once made apparent. The treatment of amaurosis must depend upon 
the extent to which it has gone, and its duration. If recent, bleeding and 
a seton in close proximity to the diseased organ will be the most likely to 
restore it. Sometimes the disease depends upon a disordered condition of 
the stomach, and then a run at grass will be the most likely means to 
restore both the affected organs to a sound state. Generally, however, an 
amaurotic eye in the horse may be considered as a hopeless case. 
BUCK EYE. 
A BUOK EYE is, strictly, rather a congenital malformation than a disease ; 
but practically, in reference to the utility of the animal, it matters little. 
It depends upon an excess of convexity in the cornea, by which the focus 
of the eye is shortened too much, the image being thus rendered indistinct 
as it falls on the retina. No treatment can be of the slightest use. 
SURFEIT. 
Aw pRvPTION of the skin, which shows itself in the form of numerous 
small scabs, matting the hair, and chiefly met with on the loins and 
