aste. In smelling, the nerves are touched by only
infinitesimally small particles of the substances reaching them, and are
only able to receive an impression from this excessive distribution.
This is also true of taste, to a certain degree, as it is impossible to
fully perceive a flavor until the substance is tolerably comminuted, as
we smack our lips to obtain it. Indeed, it may be questioned whether
the whole of taste may not lie in the capabilities of different
substances for great subdivision of particles. If quartz could be made
to dissolve into excessively minute particles as readily as sugar, it
might have its own special flavor. Some odors are offensive in dense
quantities which are highly agreeable when wafted to us in delicate
atoms,--musk, for instance. The rose secretes a volatile oil, the
wonderfully small atoms of which, on touching the nerves of smell,
communicate a peculiar sensation. This odor, like the sweetness, exists
only in the nerves affected; and a trifling disaffection of the nerves
suffices to destroy it entirely. The chemist can also analyze the oil,
but he does not enumerate in its elements odor. In fact, we have no
words to express the sensation of smell. We say sweet, sour, bitter; but
have no terms to express the differing sensations produced on us by the
rose, lily, violet, and pink. Their oily atoms awaken different
sensations in the delicate nerves they touch. The sensation awakened may
be due to chemical action induced by them in the system. But whether
chemical or physical, the result of their touch is a motion of matter,
an impulse communicated to the brain, the sensation of the organ
being--the reception of this initiative force being--what we designate
as odor. The fragrance of the rose lies, then, in the contractions of
special nerves, which thus respond to the touch of the oily particles
that are blown against them.

Does the trumpet sound? A vibration of matter causes the surrounding air
to vibrate in consonance with it; and the waves of air thus created,
breaking against the auditory nerve, awaken a peculiar sensation which
we call sound. The trumpet, vibrating variously, as the valves are moved
and the air forced through it, initiates waves of air of different
lengths; and as they are communicated to the surrounding air with
amazing rapidity, they successively strike the listener's ear. As the
waves of light touch the optic nerve, so do the grosser waves of air
touch the audit