cold paroxysm had not recovered itself, as of
the spleen, liver, kidnies, or of the stomach and intestines, or absorbent
vessels, as above mentioned.

3. Other causes are the deficiency of the natural stimuli, as hunger,
thirst, and want of fresh air. Other causes are great fatigue, want of
rest, fear, grief, or anxiety of mind. And lastly, the influence of
external ethereal fluids, as the defect of external heat, and of solar or
lunar gravitation. Of the latter the return of the paroxysms of continued
fevers about six o'clock in the evening, when the solar gravitation is the
least, affords an example of the influence of it; and the usual periods of
intermittents, whether quotidian, tertian, or quartan, which so regularly
obey solar or lunar days, afford instances of the influence of those
luminaries on these kinds of fevers.

4. If the tendency to torpor of some viscus is considerable, this will be
increased at the time, when the terrene gravitation is greatest, as
explained in the introduction to Class IV. 2. 4. and may either produce a
cold paroxysm of quotidian fever; or it may not yet be sufficient in
quantity for that purpose, but may nevertheless become greater, and
continue so till the next period of the greatest terrene gravitation, and
may then either produce a paroxysm of tertian fever; or may still become
greater, and continue so till the next period of greatest terrene
gravitation, and then produce a paroxysm of quartan ague. And lastly, the
periodical times of these paroxysms may exceed, or fall short of, the time
of greatest diurnal terrene gravitation according to the time of day, or
period of the moon, in which the first fit began; that is, whether the
diurnal terrene gravitation was then in an increasing or decreasing state.

V. _Sensation excited in Fever._

1. A curious observation is related by Dr. Fordyce in his Tract on Simple
fever, page 168. He asserts, that those people, who have been confined some
time in a very warm atmosphere, as of 120 or 130 degrees of heat, do not
feel cold, nor are subject to paleness of their skins, on coming into a
temperature of 30 or 40 degrees; which would produce great paleness and
painful sensation of coldness in those, who had been some time confined in
an atmosphere of only 86 or 90 degrees. Analogous to this, an observing
friend of mine assured me, that once having sat up to a very late hour with
three or four very ingenious and humorous companions, and dran