ruptions, and increased every kind of
inflammatory or sensitive fever.

The ease, which the patient experiences during sweating, if it be not
produced by much external heat, is similar to that of the warm bath; which
by its stimulus applied to the cutaneous vessels, which are generally
cooler than the internal parts of the system, excites them into greater
action; and pleasureable sensation is the consequence of these increased
actions of the vessels of the skin. From considering all these
circumstances, it appears that it is not the evacuation by sweats, but the
continued stimulus, which causes and supports those sweats, which is
serviceable in preventing the returns of fever-fits. And that sweats too
long continued, or induced by too great stimulus of warmth, clothes, or
medicines, greatly injure the patient by increasing inflammation, or by
exhausting the sensorial power. See Class I. 1. 2. 14.

_Secondly_, The sweats produced by exercise or labour are of the warm kind;
as they originate from the increased action of the capillaries of the skin,
owing to their being more powerfully stimulated by the greater velocity of
the blood, and by a greater quantity of it passing through them in a given
time. For the blood during violent exercise is carried forwards by the
action of the muscles faster in the arteries, than it can be taken up by
the veins; as appears by the redness of the skin. And from the consequent
sweats, it is evinced, that the secretory vessels of the skin during
exercise pour out the perspirable matter faster, than the mouths of the
absorbent vessels can drink it up. Which mouths are not exposed to the
increased muscular action, or to the stimulus of the increased velocity and
quantity of the blood, but to the cool air.

_Thirdly_, the increased secretion of perspirable matter occasioned by the
stimulus of external heat belongs likewise to this place; as it is caused
by the increased motions of the capillary vessels; which thus separate from
the blood more perspirable matter, than the mouths of their correspondent
absorbent vessels can take up; though these also are stimulated by external
heat into more energetic action. If the air be stationary, as in a small
room, or bed with closed curtains, the sweat stands in drops on the skin
for want of a quicker exhalation proportioned to the quicker secretion.

A _fourth_ variety of warm perspiration is that occasioned by stimulating
drugs, of which opium and al