being a greatful diluent in health, and salutary
in sickness, by attenuating viscid juices, promoting natural
excretions, exciting appetite, and proving particularly serviceable in
fevers, immoderate sleepiness, and head-aches after a debauch. It is
also added to the list of their ascribed virtues, that there is no
plant yet known, the infusions of which pass more freely from the body,
or more speedily excite the spirits. To a person of any physical
knowledge, these qualities will either appear contradictory in
themselves, or rather ultimately injurious, than absolutely beneficial.
As the full examination of these assumed qualities, by the rules of
science, would require a volume, instead of a few pages, which the
limits of this Essay will afford, the enquiry must be made as
perspicuous as the necessity of brevity will admit. Allowing they are
diluting in health, their constant use may so attenuate the liquids as
to destroy their natural force and tensity. But Boerhaave says, there
is no proper diluent but water; it is therefore evident it is the
water, and not the tea, which is the diluting medium. With respect to
its being an attenuative of viscid humours, it can never possess this
virtue from being a diluent, for an attenuant acts _specially_ on
the particles, by diminishing their bulk, while the diluent acts upon
the whole mass of the fluid.

The general body of the liquid may be diluted while the viscid humours
remain unresolved. Indeed, the operation of an attenuant is not easily
known; for many are surprised that a slight inflammation should be so
difficult to dissipate. But their surprise would cease, were they to
consider, that medicines act more generally upon the whole body than
abstractedly upon the part affected. Suppose to attenuate some
coagulated blood, six grains of volatile salt were given, how small a
proportion must come to the part diseased, when these grains, by the
laws of circulation, will mix with the entire mass of blood, consisting
at least of thirty pounds!

Teas being said to promote natural excretions, can be no recommendation
of what is generally used; for this constant effect must render them
too copious, and thus, according to all physical experience, the blood
must be thickened in the greater vessels, which frequently terminates
in an atrophy.

The appetite being excited by the drinking of tea, is more a proof of
its attrition of the solids than any stimulus to a wholesome desire of