sensorial power of
association; which power of association is excited by some previous or
concomitant motions of the parts of every great circle of actions. This
appears on going into the cold bath, because the shortness of breath
instantly occurs, sooner than one can conceive the diminution of the heat
of the skin could affect the lungs by the want of its stimulus; but not
sooner than the defect of the sensorial power of association could affect
them; because this must cease to be excited into action on the instant that
the cutaneous capillaries cease to act; whence in the first moment of
contact of the cold water the cutaneous capillaries cease to act from
defect of irritation; which is caused by defect of the stimulus of heat;
and in the second moment the capillaries of the lungs cease to act from the
defect of association; which is caused by the defect of the motions of the
cutaneous capillaries. Thus the universal torpor in the cold paroxysm of
fever is an example of direct sympathy, though occasioned in part by defect
of irritation, and in part by defect of association.

5. Thus in walking out in a frosty morning the skin is cooled by the
contact of the cold air, whence the actions of its capillaries are
diminished for want of their usual stimulus of heat to excite a sufficient
quantity of the sensorial power of irritation. Hence there is at first a
saving of sensorial power of irritation for the purpose of actuating the
other parts of the system with greater energy. Secondly the sensorial power
of association, which used to be excited by the motions of the cutaneous
capillaries, is now not so powerfully excited; and in consequence the
parts, which constitute the next links of the circles of associated
motions, are for a time actuated with less energy, and a temporary general
chillness succeeds; which is so far similar to the cold fit of intermittent
fever.

In this situation there is a curious circumstance occurs, which merits
peculiar attention: after a short time, though the external skin continues
cool by its exposure to the cold air, and the actions of its capillaries
are consequently diminished, yet the capillaries of the stomach act with
greater energy; as is known by increased digestion and consequent hunger.
This is to be ascribed to the accumulation of the sensorial power of
irritation, which now excites by its superabundance, or overflowing, as it
were, the stomach into increased action; though it is a