s the rosy drop; or when an inflammation of the membranes of the
kidneys is translated to the skin of the loins, and forms one kind of
herpes, called shingles; in these cases by whatever cause the original
inflammation may have been produced, as the secondary part of the train of
sensitive association is more sensible, it becomes exerted with greater
violence than the first part of it; and by both its increased pain, and the
increased motion of its fibres, so far diminishes or exhausts the sensorial
power of sensation; that the primary part of the train being less sensible
ceases both to feel pain, and to act with unnatural energy.

3. Examples of the third mode, where the primary part of a train of
sensitive association of motions may experience increased sensation, and
the secondary part increased action, are likewise not unfrequent; as it is
in this manner that most inflammations commence. Thus, after standing some
time in snow, the feet become affected with the pain of cold, and a common
coryza, or inflammation of the membrane of the nostrils, succeeds. It is
probable that the internal inflammations, as pleurisies, or hepatitis,
which are produced after the cold paroxysm of fever, originate in the same
manner from the sympathy of those parts with some others, which were
previously pained from quiescence; as happens to various parts of the
system during the cold fits of fevers. In these cases it would seem, that
the sensorial power of sensation becomes accumulated during the pain of
cold, as the torpor of the vessels occasioned by the defect of heat
contributes to the increase or accumulation of the sensorial power of
irritation, and that both these become exerted on some internal part, which
was not rendered torpid by the cold which affected the external parts, nor
by its association with them; or which sooner recovered its sensibility.
This requires further consideration.

4. An example of the fourth mode, or where the primary part of a sensitive
association of motions may have increased action, and the secondary part
increased sensation, may be taken from the pain of the shoulder, which
attends inflammation of the membranes of the liver, see Class IV. 2. 2. 9.;
in this circumstance so much sensorial power seems to be expended in the
violent actions and sensations of the inflamed membranes of the liver, that
the membranes associated with them become quiescent to their usual stimuli,
and painful in consequence.

Th