14 EXAMINATION OF HORSES 
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wheat husk purposely introduced under the upper 
eyelid of a horse suffering from cataract, for reasons 
too obvious to mention. 
The cornea, of all other structures of the eye, most 
frequently shows signs of previous disease; and when 
we allow ample room for enlargement of the pupil in 
comparative darkness, the cornea in front of the pupil 
so dilated claims our special attention; for any opa- 
cities, from whatever cause, are unsoundness so long 
as they may last, and it is for us to détermine whether 
they are temporary or permanent. The degree of 
opacity within this area must be entirely set aside, as 
there is no opacity which can be seen by us that 
will not materially interfere with the rays of light, and 
therefore with vision. When we come to remember 
how frequently the whip is abused, we must be care- 
ful in noticing the cornea of the right eye more espe- 
cially; and since we do not find the pupil fully 
dilated, we may safely allow that the eye is prac- 
tically sound if the opacity is so near the margin of 
the cornea as the sixth of an inch, and is of long 
standing—that is, that it is not progressive. Should 
any cicatrix from wound or ulcer, no matter on what 
part of the cornea it occur, alter its convexity, then 
it is unsoundness; indeed, you should always look at 
the convexity of the cornea; for if conical or too flat, 
we have not the means of rectifying the ingoing rays 
by lenses (spectacles) ; therefore such eyes cannot be 
considered sound. 
