on occasioned either by the subduction of the natural
stimuli of food, or water, or pure air, or by deficiency of external
influences, as of heat, or of solar or lunar gravitation. Or secondly, in
consequence of the exhaustion of sensorial power by great previous
exertions of some parts of the system, as of the limbs by great labour or
exercise, or of the stomach by great stimulus, as by contagious matter
swallowed with the saliva, or by much wine or opium previously taken into
it. Or lastly a torpor of a part may be occasioned by some mechanic injury,
as by a compression of the nerves of the part, or of their origin in the
brain; as the sitting long with one leg crossed over the other occasions
numbness, and as a torpor of the stomach, with vomiting frequently precedes
paralytic strokes of the limbs.

As sleep is produced, either by defect of stimulus, or by previous
exhaustion of sensorial power; so the accumulation of the sensorial power
of volition in those muscles and organs of sense, which are generally
obedient to it, awakens the sleeping person; when it has increased the
quantity of voluntarity so much as to overbalance the defect of stimulus in
one case, and the exhaustion of sensorial power in the other; which latter
requires a much longer time of sleep than the former. So the cold paroxysm
of fever is produced either by defect of stimulus, or by previous
exhaustion of the sensorial power of some part of the system; and the
accumulation of the sensorial power of irritation in that part renews the
action of it, when it has increased its irritability so much as to
overbalance the defect of stimulus in one case and the exhaustion of
sensorial power in the other; which latter requires a much longer torpor or
cold fit than the former.

But in the cold paroxysm of fever besides the torpor of one part of the
system from defect of irritation, the remainder of it becomes torpid owing
to defect of excitement of the sensorial power of association by the
lessened action of the part first affected. This torpor of the general
system remains, till the accumulation of the sensorial power of association
has increased the associability so much as to overbalance the defect of the
excitement of association; then the torpor ceases, and if the first
affected part has recovered its activity the other parts are all thrown
into excess of action by their increased associability, and the hot fit of
fever is produced.

9. In the contin