disorders in which the
exercise of the senses is in a great measure destroyed, or suspended, as in
the hydrocephalus, and apoplectic palsy, it happens not uncommonly, that
the appetite and digestion are better than in health."

* * * * *

ORDO III.

_Retrograde Irritative Motions._

GENUS I.

_Of the Alimentary Canal._

The retrograde motions of our system originate either from defect of
stimulus, or from defect of irritability. Thus sickness is often induced by
hunger, which is a want of stimulus; and from ipecacuanha, in which last
case it would seem, that the sickness was induced after the violence of the
stimulus was abated, and the consequent torpor had succeeded. Hence spice,
opium, or food relieves sickness.

The globus hystericus, salivation, diabaetes, and other inversions of
motion attending hysteric paroxysms, seem to depend on the want of
irritability of those parts of the body, because they are attended with
cold extremities, and general debility, and are relieved by wine, opium,
steel, and flesh diet; that is, by any additional stimulus.

When the longitudinal muscles are fatigued by long action, or are
habitually weaker than natural, the antagonist muscles replace the limb by
stretching it in a contrary direction; and as these muscles have had their
actions associated in synchronous tribes, their actions cease together. But
as the hollow muscles propel the fluids, which they contain, by motions
associated in trains; when one ring is fatigued from its too great
debility, and brought into retrograde action; the next ring, and the next,
from its association in train falls into retrograde action. Which continue
so long as they are excited to act, like the tremors of the hands of infirm
people, so long as they endeavour to act. Now as these hollow muscles are
perpetually stimulated, these retrograde actions do not cease as the
tremors of the longitudinal muscles, which are generally excited only by
volition. Whence the retrograde motions of hollow muscles depend on two
circumstances, in which they differ from the longitudinal muscles, namely,
their motions being associated in trains, and their being subject to
perpetual stimulus. For further elucidation of the cause of this curious
source of diseases, see Sect. XXIX. 11. 5.

The fluids disgorged by the retrograde motions of the various vascular
muscles may be distinguished, 1. From those, which are produced by
secretio