roperly simply an inaptitude to muscular motion, the limbs remaining in
any attitude in which they are placed. One patient, whom I saw in this
situation, had taken much mercury, and appeared universally torpid. He sat
in a chair in any posture he was put, and held a glass to his mouth for
many minutes without attempting to drink, or withdrawing his hand. He never
spoke, and it was at first necessary to compel him to drink broth; he
recovered in a few weeks without relapse.

10. _Hemiplegia._ Palsy of one side consists in the total disobedience of
the affected muscles to the power of volition. As the voluntary motions are
not perpetually exerted, there is little sensorial power accumulated during
their quiescence, whence they are less liable to recover from torpor, and
are thus more frequently left paralytic, or disobedient to the power of
volition, though they are sometimes still alive to painful sensation, as to
the prick of a pin, and to heat; also to irritation, as in stretching and
yawning; or to electric shocks. Where the paralysis is complete the patient
seems gradually to learn to use his limbs over again by repeated efforts,
as in infancy; and, as time is required for this purpose, it becomes
difficult to know, whether the cure is owing to the effect of medicines, or
to the repeated efforts of the voluntary power.

The dispute, whether the nerves decussate or cross each other before they
leave the cavities of the skull or spine, seems to be decided in the
affirmative by comparative anatomy; as the optic nerves of some fish have
been shewn evidently to cross each other; as seen by Haller, Elem. Physiol.
t. v. p. 349. Hence the application of blisters, or of ether, or of warm
fomentations, should be on the side of the head opposite to that of the
affected muscles. This subject should nevertheless be nicely determined,
before any one should trepan for the hydrocephalus internus, when the
disease is shewn to exist only on one side of the brain, by a squinting
affecting but one eye; as proposed in Class I. 2. 5. 4. Dr. Sommering has
shewn, that a true decussation of the optic nerves in the human subject
actually exists, Elem. of Physiology by Blumenbach, translated by C.
Caldwell, Philadelphia. This further appears probable from the oblique
direction and insertion of each optic nerve, into the side of the eye next
to the nose, in a direct line from the opposite side of the brain.

The vomiting, which generally attend