gaining none, becomes dry, and in consequence opake; for the same
reason, that wet or oiled paper is more transparent than when it is dry, as
explained in Class I. 1. 4. 1. The want of moisture in the cornea of old
people, when the exhalation becomes greater than the supply, is the cause
of its want of transparency; and which like the crystalline gains rather a
milky opacity. The same analogy may be used to explain the whiteness of the
hair of old people, which loses its pellucidity along with its moisture.
See Class I. 2. 2. 11.

M. M. Small electric shocks through the eye. A quarter of a grain of
corrosive sublimate of mercury dissolved in brandy, or taken in a pill,
twice a day for six weeks. Couching by depression, or by extraction. The
former of these operations is much to be preferred to the latter, though
the latter is at this time so fashionable, that a surgeon is almost
compelled to use it, lest he should not be thought an expert operator. For
depressing the cataract is attended with no pain, no danger, no
confinement, and may be as readily repeated, if the crystalline should rise
again to the centre of the eye. The extraction of the cataract is attended
with considerable pain, with long confinement, generally with fever, always
with inflammation, and frequently with irreparable injury to the iris, and
consequent danger to the whole eye. Yet has this operation of extraction
been trumpeted into universal fashion for no other reason but because it is
difficult to perform, and therefore keeps the business in the hands of a
few empyrics, who receive larger rewards, regardless of the hazard, which
is encountered by the flattered patient.

A friend of mine returned yesterday from London after an absence of many
weeks; he had a cataract in a proper state for the operation, and in spite
of my earnest exhortation to the contrary, was prevailed upon to have it
extracted rather than depressed. He was confined to his bed three weeks
after the operation, and is now returned with the iris adhering on one side
so as to make an oblong aperture; and which is nearly, if not totally,
without contraction, and thus greatly impedes the little vision, which he
possesses. Whereas I saw some patients couched by depression many years ago
by a then celebrated empyric, Chevalier Taylor, who were not confined above
a day or two, that the eye might gradually be accustomed to light, and who
saw as well as by extraction, perhaps better, witho