is
advantageous. Boerhaave mentions one cured of a fever by eating
red-herrings or anchovies, which, with repeated draughts of warm water or
tea, would I suppose produce copious perspiration.

Antimonial preparations have also been of late much used with great
advantage as diaphoretics. For the history and use of these preparations I
shall refer the reader to the late writers on the Materia Medica, only
observing that the stomach becomes so soon habituated to its stimulus, that
the second dose may be considerably increased, if the first had no
operation.

Where it is advisable to procure copious sweats, the emetics, as
ipecacuanha, joined with opiates, as in Dover's powder, produce this effect
with greater certainty than the above.

8. We must not dismiss this subject without observing, that perspiration is
designed to keep the skin flexile, as the tears are intended to clean and
lubricate the eye; and that neither of these fluids can be considered as
excretions in their natural state, but as secretions. See Class I. 1. 2. 3.
And that therefore the principal use of diaphoretic medicines is to warm
the skin, and thence in consequence to produce the natural degree of
insensible perspiration in languid habits.

9. When the skin of the extremities is cold, which is always a sign of
present debility, the digestion becomes frequently impaired by association,
and cardialgia or heartburn is induced from the vinous or acetous
fermentation of the aliment. In this disease diaphoretics, which have been
called cordials, by their action on the stomach restore its exertion, and
that of the cutaneous capillaries by their association with it, and the
skin becomes warm, and the digestion more vigorous.

10. But a blister acts with more permanent and certain effect by
stimulating a part of the skin, and thence affecting the whole of it, and
of the stomach by association, and thence removes the most obstinate
heartburns and vomitings. From this the principal use of blisters is
understood, which is to invigorate the exertions of the arterial and
lymphatic vessels of the skin, producing an increase of insensible
perspiration, and of cutaneous absorption; and to increase the action of
the stomach, and the consequent power of digestion; and thence by sympathy
to excite all the other irritative motions: hence they relieve pains of the
cold kind, which originate from defect of motion; not from their
introducing a greater pain, as some have