their connection with it, and the cold fit of fever
is produced.

VIII. There are many other causes, which produce quiescence of some part of
the animal system, as fatigue, hunger, thirst, bad diet, disappointed love,
unwholesome air, exhaustion from evacuations, and many others; but the last
cause, that we shall mention, as frequently productive of cold fits of
fever, is fear or anxiety of mind. The pains, which we are first and most
generally acquainted with, have been produced by defect of some stimulus;
thus, soon after our nativity we become acquainted with the pain from the
coldness of the air, from the want of respiration, and from the want of
food. Now all these pains occasioned by defect of stimulus are attended
with quiescence of the organ, and at the same time with a greater or less
degree of quiescence of other parts of the system: thus, if we even endure
the pain of hunger so as to miss one meal instead of our daily habit of
repletion, not only the peristaltic motions of the stomach and bowels are
diminished, but we are more liable to coldness of our extremities, as of
our noses, and ears, and feet, than at other times.

Now, as fear is originally excited by our having experienced pain, and is
itself a painful affection, the same quiescence of other fibrous motions
accompany it, as have been most frequently connected with this kind of
pain, as explained in Sect. XVI. 8. 1. as the coldness and paleness of the
skin, trembling, difficult respiration, indigestion, and other symptoms,
which contribute to form the cold fit of fevers. Anxiety is fear continued
through a longer time, and, by producing chronical torpor of the system,
extinguishes life slowly, by what is commonly termed a broken heart.

IX. 1. We now step forwards to consider the other symptoms in consequence
of the quiescence which begins the fits of fever. If by any of the
circumstances before described, or by two or more of them acting at the
same time, a great degree of quiescence is induced on any considerable part
of the circle of irritative motions, the whole class of them is more or
less disturbed by their irritative associations. If this torpor be
occasioned by a deficient supply of sensorial power, and happens to any of
those parts of the system, which are accustomed to perpetual activity, as
the vital motions, the torpor increases rapidly, because of the great
expenditure of sensorial power by the incessant activity of those parts of
the