ty: and the effect produced by this
action, we call excitement.

2. The state of accumulation, produced by the absence or diminished
action of the accustomed stimuli.

3. The state of exhaustion, produced by the too powerful action of
stimuli; and this may be produced either by the too powerful, or long
continued action of the common stimulants which support life, such as
food, air, heat, and exercise; or it may be caused by an application
of stimulants, which act more powerfully on the excitability, and
which exhaust it more quickly, such as wine, spirits, and opium,
musk, camphor, and various other articles used in medicines.

The state of health, or tone, if we use that term, consists therefore
in a certain quantity or energy of excitability necessary to its
preservation. To maintain this state, the action of the stimuli
should be strong enough to carry off from the body the surplus of
this irritable principle. To obtain this end, a certain equilibrium
is necessary between the excitability and the stimuli applied, or the
sum of all the stimuli acting upon it must be always nearly equal,
and sufficient to prevent an excess of excitability, but not so
strong as to carry off more than this excess. It is in this
equilibrium between the acting stimuli and the excitability, that the
health, or tone of the living body consists.

When the sum of the stimuli, acting on the body, is so small, as not
to carry off the excess of excitability, it accumulates, and diseases
of irritability are produced. Of this nature are those diseases to
which the poor are often subject, and which will be particularly
considered hereafter.

When the sum of the stimuli acting on the body, is too great, it is
deprived not only of the excess of excitability, but also of some
portion of the irritable principle necessary for the tone of the
body: or, to speak more distinctly, the body loses more excitability
than it receives, and of course must, in a short time, be in a state
of exhaustion. This gives rise to diseases which afflict drinkers, or
those who indulge in any kind of intemperance, or persons born in
climates where the temperature is moderate, but who emigrate to those
which are much warmer.

Thus we have endeavoured, after the example of Dr. Brown, to
ascertain the cause of the healthy state, before the causes of
diseases were investigated; and though this is contrary to the
general practice, yet it must be evident to every one, that