ringency more than one
tried by the above writer, Dr. Priestley. Endeavouring to trace the
differences and ascertain the astringency and bitterness of vegetables
reciprocally bear to each other, he imagined he had found they were
distinct and separate properties, by the following experiment: Taking
two pieces of calf-skin just stripped from the calf, he immerged them
in cold infusions of green and bohea tea; at the expiration of a week
he found they were hard and curled up, and that there was no sensible
difference between them. He therefore concluded, that this experiment
afforded a striking proof of India tea differently affecting a dead and
a living fibre; this he considered as the greatest effect of a
medicine. But, with deference to so distinguished an author, I cannot
but attribute this astringency of the skin to the particular properties
of India tea; for all physical as well as medical experience proves
that vegetable produce afford some that are astringent, and others that
are relaxant, of the dead as well as the living fibre. Oak bark is
equally astringent, and hardens the fibres of the hide, as well as it
braces the living nerve of our bodies; therefore the effect produced by
the India tea upon the dead skin only proves, what we have before
related, that an infusion of it has a peculiar effect, which, being too
frequently applied to the nerves, destroys their tensity by their fine
fibres being either broken or relaxed by overbracing. Were any
astringent to be constantly taken, it must ultimately produce more or
less such an effect; so that while the above experiment of the learned
Philosopher demonstrates that India tea has the power of astringing the
dead as well as the living fibres, it does not prove that astringency
bitterness are separate qualities. On the contrary, bitterness seems to
be the characteristic taste of all that has the tendency to contract
whatever is the subject of its application. Thus galls, bark, rhubarb,
camomile tea, &c. &c. are all bitter and astringent. It is, therefore,
the immoderate use of such an astringent that ultimately relaxes and
debilitates: like the too frequent bracing of a drum, or any other
stringed musical instrument, destroys its tensity, the body is unnerved
by the overstretching of its fibres. Although we sometimes differ with
the celebrated Doctor in part of the conclusion he has drawn from his
experiment, yet the following sentiments so perfectly coincide with all