ges between predisposition and disease,
but does not in general actually reach disease; or rather, it is a
state of the excitement, so far departing from the point of perfect
health, that the functions are not performed with that alacrity, or
vigour, which ought to take place; but labour under that disturbed
and uneasy action, which, though it cannot be called actual disease,
yet deviates considerably from the point of perfect health.

This is a new view of these diseases, but the more I have examined
it, the more I am convinced that it is just. Indeed, the name,
nervous, has generally been given to an assemblage of symptoms, which
the physicians did not understand; and when the patient relates a
history of symptoms, and expects that his physician shall inform him
of the name, and nature of his complaint, he generally receives for
answer, that his complaints are nervous, or bilious; terms which
convey no distinct ideas, but which serve to satisfy the patient, and
to conceal the ignorance of the physician, or spare him the labour of
thinking.

Indeed, the idea of nervous diseases, which I have already pointed
at, is not only new, but could only have arisen from such a view as
we have been taking of the states of excitement and excitability.
This view will not only lead us to form a more just idea of the
manner in which these diseases originate, but will point out a
distinction of them into two classes, of the utmost use in practice,
but which distinction has totally escaped the attention of
practitioners; for though these complaints have been generally
thought to arise from a lowness of the nervous energy, or some kind
of debility, or weakness of the nervous system, and, on this account,
the stimulant and cordial plan of cure has been recommended, I am
convinced, from observation, that nearly one half of them, if not
more, originate from a state of the excitement verging towards
sthenic disease; and in these cases, this general mode of treatment
must be highly improper.

It has been already shown, that when the common exciting powers which
support life, act in such a manner, that a middle degree of exciting
power, acts upon a middle degree of excitability, the most perfect
state of the system, or a state of perfect health, takes place: it
is, however, seldom in our power so to proportion the state of
excitement and excitability to each other. The action of the exciting
powers is continually varying in strength; and t