hich, if
received into the stomach, would taint the whole mass of fluids, and
bring on speedy dissolution.

The seat of this sense is a soft pulpy membrane, full of pores, and
small vessels, which lines the whole internal cavity of the nose. On
this membrane are distributed abundance of soft nerves, which arise
chiefly from an expansion of the first pair of nerves coming from the
brain. This membrane is likewise plentifully supplied with arteries;
so that by means of this nervous and arterial apparatus, this
membrane is possessed of very great sensibility; but the nerves of
the nose being almost naked, require a defence from the air, which is
continually drawn through the nostrils into the lungs, and forced out
again by respiration. Nature has therefore supplied this part with a
thick insipid mucus, very fluid at its first separation, but
gradually thickening, as it combines with oxygen, into a dry crust,
approaching often to a membranous matter. This mucus is poured out,
or exhaled, by the numerous minute arteries of the nostrils, and
serves to keep the nervous apparatus moist, and in a proper state for
receiving impressions, as well as to prevent the violent effects
which might arise from the stimulus of the air and other bodies. The
sense of smell is the most acute about the middle of the septum of
the nose, where the nervous membrane which I have described is
thicker and softer, than in the cavities more deeply situated, where
it is less nervous and vascular. These parts are not however
destitute of the sense.

As taste proceeds from the action of the soluble parts of bodies on
the nervous papillae of the tongue, so smell is occasioned by minute
and volatile particles flying off from bodies, which become mixed
with the air, and drawn up with it into the nostrils, where these
small particles stimulate or act upon the nerves before described,
and produce the sensation which we call smelling.

The air therefore, being loaded with the subtile and invisible
effluvia of bodies, is, by the powers of respiration, drawn through
the nose, so as to apply these particles to the almost naked
olfactory nerves, which, as was before observed, excites the sense of
smelling. When we wish to smell accurately, we shut the mouth, open
the nostrils as wide as possible, and making a strong inhalation,
draw up a greater number of these volatile particles, than could be
drawn up by the common action of respiration, by which means the
o