f,
abounds with similar microscopic animals.

4. Young children have sometimes an eruption upon the head called Tinea,
which discharges an acrimonius ichor inflaming the parts, on which it
falls. This eruption I have seen submit to the internal use of vitriolic
acid, when only wheat-flour was applied externally. This kind of eruption
is likewise frequently cured by testaceous powders; two materials so widely
different in their chemical properties, but agreeing in their power of
promoting cutaneous absorption.

II. Absorption from the mucous membrane is increased by applying to its
surface the austere acids, as of vitriol, lemon-juice, crab-juice, sloes.
When these are taken into the mouth, they immediately thicken, and at the
same time lessen the quantity of the saliva; which last circumstance cannot
be owing to their coagulating the saliva, but to their increasing the
absorption of the thinner parts of it. So alum applied to the tip of the
tongue does not stop in its action there, but independent of its diffusion
it induces cohesion and corrugation over the whole mouth. (Cullen's Mat.
Med. Art. Astringentia.) Which is owing to the association of the motions
of the parts or branches of the absorbent system with each other.

Absorption from the mucous membrane is increased by opium taken internally
in small doses more than by any other medicine, as is seen in its
thickening the expectoration in coughs, and the discharge from the nostrils
in catarrh, and perhaps the discharge from the urethra in gonorrhoea. The
bark seems next in power for all these purposes.

Externally slight solutions of blue vitriol, as two or three grains to an
ounce of water, applied to ulcers of the mouth, or to chancres on the glans
penis, more powerfully induces them to heal than any other material.

Where the lungs or urethra are inflamed to a considerable degree, and the
absorption is so great, that the mucus is already too thick, and adheres to
the membrane from its viscidity, opiates and bitter vegetable and austere
acids are improper; and mucilaginous diluents should be used in their stead
with venesection and torpentia.

III. 1. Absorption from the cellular membrane, and from all the other
cavities of the body, is too slowly performed in some constitutions; hence
the bloated pale complexion; and when this occurs in its greatest degree,
it becomes an universal dropsy. These habits are liable to intermittent
fevers, hysteric paroxysms, c