ile
those that show a radiating arrangement are in the lens (lenticular),
the radiating fibers of which the exudate follows. Black cataracts are
formed by the adhesion of the pigment on the back of the iris to the
front of the lens, and by the subsequent tearing loose of the iris,
leaving a portion of its pigment adherent to the capsule of the lens. If
the pupil is so contracted that it is impossible to see the lens, it may
be dilated by applying to the front of the eye with a feather some drops
of a solution of 4 grains of atropia in an ounce of water.

_Treatment._--The treatment of internal ophthalmia should embrace,
first, the removal of all existing causes or sources of aggravation of
the disease, which need not be repeated here. Special care to protect
the patient against strong light, cold, wet weather, and active exertion
must, however, be insisted on. A dark stall and a cloth hung over the
eye are important, while cleanliness, warmth, dryness, and rest are
equally demanded. If the patient is strong and vigorous, a dose of 4
drams of Barbados aloes may be given, and if there is any reason to
suspect a rheumatic origin one-half a dram powdered colchicum and
one-half ounce salicylate of soda may be given daily. Locally the
astringent lotions advised for external ophthalmia may be resorted to,
especially when the superficial inflammation is well marked. More
important, however, is to instill into the eye, a few drops at a time, a
solution of 4 grains of atropia in 1 ounce of distilled water. This may
be effected with the aid of a soft feather, and may be repeated at
intervals of 10 minutes until the pupil is widely dilated. As the horse
is to be kept in a dark stall, the consequent admission of light will be
harmless, and the dilation of the pupil prevents adhesion between the
iris and lens, relieves the constant tension of the eye in the effort to
adapt the pupil to the light, and solicits the contraction of the blood
vessels of the eye and the lessening of congestion, exudation, and
intraocular pressure. Should atropia not agree with the case, it may be
replaced by morphia (same strength) or cocaine in 4 per cent solution.
Another local measure is a blister, which can usually be applied to
advantage on the side of the nose or beneath the ear. Spanish flies may
be used as for external ophthalmia. In very severe cases the parts
beneath the eye may be shaved and three or four leeches applied. Setons
are sometimes be