it if continued too long by
direct sympathy; so in the circumstance above mentioned the action of the
stomach is increased by direct sympathy with that of the skin; and the
tendency to vomit, which was owing to its diminished action, ceases.

3. _Cessatio aegritudinis cute excitata._ The cure of sickness by
stimulating the skin. This is explained in the preceding article; and
further noticed in IV. 2. 2. 4. and in IV. 1. 1. f.

Similar to these is the effect of a blister on the back in relieving
sickness, indigestion, and heart-burn; and, on the contrary, by these
symptoms being frequently induced by coldness of the extremities. The
blister stimulates the cutaneous vessels into greater action; whence warmth
and pain are produced at the same time, and the fibres of the stomach are
excited into greater action by their association with those of the skin. It
does not appear, that the concomitant pain of the blister causes the
increased energy of the stomach, because the motions of it are not greater
than natural; though it is sometimes difficult to determine, whether the
primary part of some associated trains be connected with irritative or
sensitive motions.

In the same manner a flannel shirt, to one who has not been in the habit of
wearing one, stimulates the skin by its points, and thus stops vomiting in
some cases; and is particularly efficacious in checking some chronical
diarrhoeas, which are not attended with fever; for the absorbents of the
skin are thus stimulated into greater action, with which those of the
intestines consent by direct sympathy.

This effect cannot be ascribed to the warmth alone of the flannel shirt, as
being a covering of loose texture, and confining air in its pores, like a
sponge, which air is known to be a bad conductor of heat, since in that
case its use should be equally efficacious, if it were worn over a linen
shirt; and an increased warmth of the room of the patient would be equally
serviceable.

4. _Digestio aucta frigore cutaneo._ Digestion increased by coldness of the
skin. Every one has experienced the increase of his appetite after walking
in the cool air in frosty days; for there is at this time not only a saving
of sensorial power by the less exertion of the cutaneous vessels; but, as
these consent with those of the stomach and bowels, this saving of
sensorial power is transferred by reverse sympathy from the cutaneous
capillaries and absorbents to those of the stomach and in