530 
OBSERVATIONS ON SOUNDNESS. 
attention. The owner is of opinion the horse is sound; he 
offers him for sale at a fair; he succeeds in parting with 
him, subject to the examination of a veterinary surgeon. 
This may be in the month of July, August, or September, 
when the weather is extremely hot and the day bright. In 
all probability there is no house near the spot in which the 
horse can be placed for the examination of the eyes to be 
proceeded with. The muscles of the iris have effectually 
done their work, so as to baffle all the attempts of the 
examiner to look beyond the iris, and the horse is returned 
as a sound one, because of the contraction of the pupil, lie 
is said to be all right in this respect. A horse may 
be totally blind, and yet contraction of the pupil take 
place. 
In simple ophthalmia the eye generally becomes sound and 
healthy, unless a small feather-like opacity remains from the 
injury. In old cases of keratitis, we frequently find traces of 
disease which will, more or less, intercept the pencils of light 
as they proceed to the retina, AVith such cases it is not very 
difficult to deal. They are of necessity unsound. The diseases 
of the cornea, iris, capsule of the lens, lens, vitreous humour, 
and retina, are those we have chiefly to consider, although a 
passing thought may be spent upon the palpebrae; injuries to 
which now and then require that a portion of either one or 
the other be excised. 
I think the time has nearly passed for any person, however 
antiquated his views may be, to think of excising the cartilago 
nictitans, although I sometimes hear of such a complaint as 
the existing. Keratitis, or inflammation of the cornea, 
is a complaint of some moment to the veterinary surgeon, 
because an attack of simple inflammation is likely to extend 
to this structure. The fact of there being more than one 
layer in the cornea, renders the disease more complicated in 
its treatment than it would be if one only was present. 
Indeed, I think this remark holds good in the treatment of 
all diseases. 
It is not probable we shall have our attention directed to a 
case for inspection until it assumes a chronic stage, which 
can be readily known by the colour of the membrane. If not 
perfectly transparent it must be held an unsoundness. The 
aqueous humour is not liable to a distinct disease that I am 
aware of. The next tissue in order will be the iris. IritU 
often follows an attack of keratitis, and is frequently its accom¬ 
paniment; the result of which, if not taken care of by the prac¬ 
titioner, is an adhesion of some of the fibres of the iris to the 
capsule of the lens, which will interfere more or less with its 
