sensorial exertion, and a consequent quiescence of a great part of the
system. This quiescence continues, till the sensorial power becomes again
accumulated in the torpid organs; and then the usual diurnal stimuli excite
the revivescent parts again into action; but as this kind of quiescence
continues but a short time compared to the cold paroxysm of an ague, and
less affects the circulatory system, a less superabundancy of exertion
succeeds in the organs previously torpid, and a less excess of arterial
activity. See Sect. XXXIV. 1. 6.

2. In the diseases occasioned by a defect of sensorial exertion, as in cold
fits of ague, hysteric complaint, and nervous fever, the following means
are those commonly used. 1. Increase the stimulation above its natural
quantity for some weeks, till a new habit of more energetic contraction of
the fibres is established. This is to be done by wine, opium, bark, steel,
given at exact periods, and in appropriate quantities; for if these
medicines be given in such quantity, as to induce the least degree of
intoxication, a debility succeeds from the useless exhaustion of spirit of
animation in consequence of too great exertion of the muscles or organs of
sense. To these irritative stimuli should be added the sensitive ones of
cheerful ideas, hope, affection.

3. Change the kinds of stimulus. The habits acquired by the constitution
depend on such nice circumstances, that when one kind of stimulus ceases to
excite the sensorial power into the quantity of exertion necessary to
health, it is often sufficient to change the stimulus for another
apparently similar in quantity and quality. Thus when wine ceases to
stimulate the constitution, opium in appropriate doses supplies the defect;
and the contrary. This is also observed in the effects of cathartic
medicines, when one loses its power, another, apparently less efficacious,
will succeed. Hence a change of diet, drink, and stimulating medicines, is