cream and
tea, or with milk, and holding it to your lips, as if going to drink it,
the imperfections of the cornea will appear like lines or blotches on the
surface of the fluid, with a less white appearance than that surface. Those
blemishes of the eye are distinguished from the muscae volitantes described
in Class I. 2. 5. 3. by their being invariably seen at any time, when you
look for them.

Ulcers may frequently be seen on the cornea after ophthalmy, like little
pits or indentations beneath the surface of it: in this case no external
application should be used, lest the scar should be left uneven; but the
cure should be confined to the internal use of thirty grains of bark twice
a day, and from five to ten drops of laudanum at night, with five grains of
rhubarb, if necessary.

After ulcers of the cornea, which have been large, the inequalities and
opacity of the cicatrix obscures the sight; in this case could not a small
piece of the cornea be cut out by a kind of trephine about the size of a
thick bristle, or a small crow-quill, and would it not heal with a
transparent scar? This experiment is worth trying, and might be done by a
piece of hollow steel wire with a sharp edge, through which might be
introduced a pointed steel screw; the screw to be introduced through the
opake cornea to hold it up, and press it against the cutting edge of the
hollow wire or cylinder; if the scar should heal without losing its
transparency, many blind people might be made to see tolerably well by this
slight and not painful operation. An experiment I wish strongly to
recommend to some ingenious surgeon or oculist.

* * * * *

ORDO I.

_Increased Irritation._

GENUS IV.

_With increased Actions of other Cavities and Membranes._

SPECIES.

1. _Nictitatio irritativa._ Winking of the eyes is performed every minute
without our attention, for the purpose of cleaning and moistening the
eye-ball; as further spoken of in Class II. 1. 1. 8. When the cornea
becomes too dry, it becomes at the same time less transparent; which is
owing to the pores of it being then too large, so that the particles of
light are refracted by the edges of each pore, instead of passing through
it; in the same manner as light is refracted by passing near the edge of a
knife. When these pores are filled with water, the cornea becomes again
transparent. This want of transparency of the cornea is visible sometimes
in dying peop