examiner. It is advisable on approaching the animal to stroke its face, and
in the horse to brush its foretop away. The hand should be carried slowly
to the front of the eye, and the lids separated with the fingers and thumb
if we wish to obtain a better view of the cornea. In cattle the best view
of these parts can be obtained by taking hold of the nose and lifting the
head. It is impossible to make a satisfactory examination of the eye
outside of the stable where the light is coming from all directions. The
most satisfactory conditions under which a general examination can be made
is to stand the animal facing a transom, window or open door. We may then
look directly into the eye and note the condition of the different
refracting media.

The lens should appear transparent and free from scars. The aqueous humor
free from any cloudiness or precipitate. Both pupillary openings should be
the same size, and not too small or too large in the bright light. As we
look through the pupillary openings, both the lens and the vitreous humor
should refract the light properly and not appear white or greenish-white in
color. The color of the iris should be noted. If it lacks lustre or appears
dull, this may indicate an inflammation. In periodic ophthalmia in horses
the iris loses its lustre and becomes a rusty-brown color. It is very
important to note this change in the appearance of the iris. We should
note, in addition, the expression of the animal's face, the position of the
ears and eyelids and manner of the walk. Horses that have defective sight
may show a deep wrinkle in the upper eyelid when startled or looking
directly at an object. Animals that are blind hold the ears in a
characteristic position, and may stumble and walk over, or run into objects
unless stopped. The ophthalmoscope is a very useful instrument for
determining the condition of the different structures of the eyes, when in
the hands of persons who are trained in its use.