o are frozen to
death.

If the deficiency of heat be in less degree, but yet so great as in some
measure to disorder the system, and should occur the succeeding day, it
will induce a greater degree of quiescence than before, from its acting in
concurrence with the period of the diurnal circle of actions, explained in
Sect. XXXVI. Hence from a small beginning a greater and greater degree of
quiescence may be induced, till a complete fever-fit is formed; and which
will continue to recur at the periods by which it was produced. See Sect.
XVII. 3. 6.

If the degree of quiescence occasioned by defect of the stimulus of heat be
very great, it will recur a second time by a slighter cause, than that
which first induced it. If the cause, which induces the second fit of
quiescence, recurs the succeeding day, the quotidian fever is produced; if
not till the alternate day, the tertian fever; and if not till after
seventy-two hours from the first fit of quiescence, the quartan fever is
formed. This last kind of fever recurs less frequently than the other, as
it is a disease only of those of the temperament of associability, as
mentioned in Sect. XXXI.; for in other constitutions the capability of
forming a habit ceases, before the new cause of quiescence is again
applied, if that does not occur sooner than in seventy-two hours.

And hence those fevers, whose cause is from cold air of the night or
morning, are more liable to observe the solar day in their periods; while
those from other causes frequently observe the lunar day in their periods,
their paroxysms returning near an hour later every day, as explained in
Sect. XXXVI.

IV. Another frequent cause of the cold fits of fever is the defect of the
stimulus of distention. The whole arterial system would appear, by the
experiments of Haller, to be irritable by no other stimulus, and the
motions of the heart and alimentary canal are certainly in some measure
dependant on the same cause. See Sect. XIV. 7. Hence there can be no
wonder, that the diminution of distention should frequently induce the
quiescence, which constitutes the beginning of fever-fits.

Monsieur Leiutaud has judiciously mentioned the deficiency of the quantity
of blood amongst the causes of diseases, which he says is frequently
evident in dissections: fevers are hence brought on by great haemorrhages,
diarrhoeas, or other evacuations; or from the continued use of diet, which
contains but little nourishment; or