already inclined to
act more powerfully; as the blood-vessels being less distended, there is
less resistance to the progress of the absorbed fluids into them. Hence
after evacuations opium promotes absorption, if given in small doses, much
more than it promotes secretion; and is thus eminently of service at the
end of inflammations, as in pleurisy, or peripneumony, in the dose of four
or five drops of the tincture, given before the access of the evening
paroxysm; which I have seen succeed even when the risus sardonicus has
existed. Some convulsions may originate in the want of the absorption of
some acrid secretion, which occasions pain; hence these diseases are so
much more certainly relieved by opium after venesection or other
evacuations.

IX. 1. Absorption is increased by the calces or solutions of mercury, lead,
zinc, copper, iron, externally applied; and by arsenic, and by sulphur, and
by the application of bitter vegetables in fine powder. Thus an ointment
consisting of mercury and hog's fat rubbed on the skin cures venereal
ulcers; and many kinds of herpetic eruptions are removed by an ointment
consisting of 60 grains of white precipitate of mercury and an ounce of
hog's fat.

2. The tumours about the necks of young people are often produced by the
absorption of a saline or acrid material, which has been deposited from
eruptions behind the ears, owing to deficient absorption in the surface of
the ulcer, but which on running down on the skin below becomes absorbed,
and swells the lymphatic glands of the neck; as the variolous matter, when
inserted into the arm, swells the gland of the axilla. Sometimes the
perspirative matter produced behind the ears becomes putrid from the want
of daily washing them, and may also cause by its absorption the tumours of
the lymphatics of the neck. In the former case the application of a cerate
of lapis calaminaris, or of cerussa applied in dry powder, or of rags
dipped in a solution of sugar of lead, increases the absorption in the
ulcers, and prevents the effusion of the saline part of the secreted
material. The latter is to be prevented by cleanliness.

After the eruptions or ulcers are healed a solution of corrosive sublimate
of one grain to an ounce of water applied for some weeks behind the ear,
and amongst the roots of the hair on one side of the head, where the mouths
of the lymphatics of the neck open themselves, frequently removes these
tumours.

3. Linen rags moiste