Thus far I have chiefly endeavoured to trace the effects of Tea as
a part of our diet. In medicine it has at present but very little
reputation amongst us. It is even scarcely ever recommended as a
part of the furniture of a sick chamber; it is seldom mentioned even
as a gentle diaphoretic: in cases, however, where it is necessary
to dilute and relax, to promote the thinner secretions, it promises
at least as much advantage as most other infusions. For, besides
its other effects, it seems to contain something sedative in its
composition (SECT. II. EXP. III. IV.), not altogether unlike an
opiate. Like this class of medicines, it mitigates uneasiness,
perhaps more than any other merely aqueous infusion: and, like
very small doses of opium, it sometimes prevents rest, and gives a
temporary flutter to the spirits.
Where, therefore, large quantities of the infusion must be taken,
to produce or support a considerable diaphoresis, a decoction of
Tea, or a strong infusion, may be administered with great propriety,
particularly in inflammatory complaints; the sedative power of
Tea, assisted by the diluting effects of warm water, generally
producing a diaphoresis, without stimulating the system. The Chinese
most commonly give it as a medicine in decoction, in a variety of
diseases; but if the infusion were drawn from a large proportion of
fine Tea, and soon poured off, that the finest part may be procured,
and drank warm, it would seem preferable as an attenuant and relaxant.
I have more than once given fine green Tea in substance with some
diluting vehicle, and observed the same effects nearly as are
produced from taking the infusion. Thirty grains of this kind of
Tea powdered, taken three or four times at as many hours interval,
generally relaxes the solids, diminishes heat and restlessness, and
induces perspiration. Such a dose as produces a slight nausea, which
this quantity usually does, more certainly induces a perspiration,
and a mitigation of the symptoms accompanying inflammatory
complaints. If this dose be doubled, the nausea and sickness will
be increased, and a disagreeable sensation or load is felt for some
time about the region of the stomach, which usually goes off with a
laxative stool.