ich might
have terminated in death.

I have seen various instances where patients have complained of this
unusual depression, and inability to move: they have shown me
prescriptions in which the stimulant or tonic plan was recommended,
but instead of any alleviation the symptoms had become worse from
their use. This hint was generally sufficient, for if the disease of
predisposition had been asthenic, cordials and tonics ought to have
relieved it: if, on inquiry, I found the exciting powers had acted
too powerfully, I then, without hesitation, had recourse to the
debilitating plan, and with the greatest certainty of success. Before
I viewed diseases and their causes in this way, I must confess that I
often felt great hesitation in practice; and judging merely from
symptoms, which are frequently very fallacious, the operation of a
remedy often disappointed me, and I could not pretend to predict the
event with the certainty that I now can. This observation is of the
greatest consequence in the cure both of predisposition and of
disease. Though excitement regulates all the phenomena of life, yet
the symptoms of diseases which either its excess or deficiency
produces, do not of themselves lead to any proper judgment respecting
it. On the contrary their fallacious appearance has proved the source
of infinite error.

As excitement both depends on exciting powers and excitability, it is
evident that when a middle degree of stimulus acts upon a middle
degree of excitability, the most perfect effect will be produced.
This point, could we ascertain it, might be called the point of
health. For the sake of illustration, we may suppose that the
greatest excitability of which the living body is capable is 80
degrees: this may be supposed to be the excitability possessed by the
body at the commencement of its life, because no part has then been
wasted or exhausted by the action of stimuli. Now, if we suppose a
scale of excitability to be formed, and divided into 80 equal parts
or degrees, the excitability will be wasted or exhausted in
proportion to the application of stimuli, from the beginning to the
end of the scale. One degree of exciting power applied takes off one
degree of excitability, and every subsequent degree impairs the
excitability in proportion to its degree of force. Thus a degree of
stimulus or exciting power equal to 10 will reduce the excitability
to 70, 20 to 60, 30 to 50, 40 to 40, 50 to 30, 60 to 20, 70 to 10,