th those of the skin; and hence their motions are so associated
together, that when one is affected either with quiescence or exertion, the
other sympathizes with it, according to the laws of irritative association.
See Sect. XXVII. 1. on haemorrhages.

Besides the quiescence of the minute vessels of the lungs, there are many
other systems of vessels which become torpid from their irritative
associations with those of the skin, as the absorbents of the bladder and
intestines; whence an evacuation of pale urine occurs, when the naked skin
is exposed only to the coldness of the atmosphere; and sprinkling the naked
body with cold water is known to remove even pertinacious constipation of
the bowels. From the quiescence of such extensive systems of vessels as the
glands and capillaries of the skin, and the minute vessels of the lungs,
with their various absorbent series of vessels, a great accumulation of
sensorial powers is occasioned; part of which is again expended in the
increased exertion of all these vessels, with an universal glow of heat in
consequence of this exertion, and the remainder of it adds vigour to both
the vital and voluntary exertions of the whole day.

If the activity of the subcutaneous vessels, and of those with which their
actions are associated, was too great before cold immersion, as in the hot
days of summer, and by that means the sensorial power was previously
diminished, we see the cause why the cold bath gives such present strength;
namely, by stopping the unnecessary activity of the subcutaneous vessels,
and thus preventing the too great exhaustion of sensorial power; which, in
metaphorical language, has been called _bracing_ the system: which is,
however, a mechanical term, only applicable to drums, or musical strings:
as on the contrary the word _relaxation_, when applied to living animal
bodies, can only mean too small a quantity of stimulus, or too small a
quantity of sensorial power; as explained in Sect. XII. 1.

3. This experiment of cold bathing presents us with a simple fever-fit; for
the pulse is weak, small, and quick during the cold immersion; and becomes
strong, full, and quick during the subsequent glow of heat; till in a few
minutes these symptoms subside, and the temporary fever ceases.

In those constitutions where the degree of inirritability, or of debility,
is greater than natural, the coldness and paleness of the skin with the
quick and weak pulse continue a long time aft