DISEASES AND TREATMENT OF THE HORSE 219 
image of objects in front of the eye may be reflected upon 
the sensitive portions on the inside and thus carried by the 
optic nerve to the brain. In this manner animals are 
possessed of the sense of sight. Should the admission of the 
rays of light be obstructed from any cause, total or partial 
blindness is the result, according to the degree of obstruction. 
A cataract is an opaque, pearly white deposit across the 
pupil. It may be what is termed partial or complete for the 
reasons above stated, and may affect one or both eyes. 
Causes. — Cataract is sometimes present at the time of 
birth. Repeated attacks of inflammation such as in a case of 
ophthalmia will cause it. 
Symptoms. — The white portion is quite clearly seen. 
There is whole or partial blindness. 
Treatment. — Very little, if anything, can be done, unless 
by an operation, and such an operation is not attended with 
but slight success in the horse, because of the impossibility 
to regulate the sight with glasses as is done with people. As 
for medicine, when the cataract is well formed there can be 
nothing given which is effective. 
It is an important matter to examine the eyes of a horse 
carefully before purchasing him, to see that no indications of 
cataract are present. 
4. Star Gazer (Amaurosis). 
This is paralysis of the optic nerve, the function of which 
is to carry to the brain impressions reflected upon the retina. 
Causes. — A sudden jar or injury to the head, standing in 
a dark stable or sudden exposure to extremely bright light 
may paralyze this nerve. The loss of a great deal of blood 
sometimes causes a temporary paralysis, but the sight returns 
with the re-established circulation. 
Symptoms. — The eye has a large, glassy appearance, and 
the pupil of the eye is very much enlarged. If taken from a 
dark stable into the light the pupil of the eye does not close 
up to regulate the admission of light as if it were in good 
condition, but remains large. He generally carries his head 
high and steps high. 
Treatment. — If the case is of long standing nothing can 
be done for it ; if the result of injury by striking the head 
against something, or of bleeding, it can be treated success- 
fully. Give a teaspoonful of nux vomica in the feed three 
