f the
profession, particular care is required whilst endeavouring to mark
its diagnostic characters. It is sufficient, in general, to point out
the characteristic differences which are observable between diseases
in some respects resembling each other. But in this case more is
required: it is necessary to show that it is a disease which does not
accord with any which are marked in the systematic arrangements of
nosologists; and that the name by which it is here distinguished has
been hitherto vaguely applied to diseases very different from each
other, as well as from that to which it is now appropriated.

Palsy, either consequent to compression of the brain, or dependent on
partial exhaustion of the energy of that organ, may, when the palsied
limbs become affected with tremulous motions, be confounded with this
disease. In those cases the abolition or diminution of voluntary
muscular action takes place suddenly, the sense of feeling being
sometimes also impaired. But in this disease, the diminution of the
influence of the will on the muscles comes on with extreme slowness,
is always accompanied, and even preceded, by agitations of the
affected parts, and never by a lessened sense of feeling. The dictates
of the will are even, in the last stages of the disease, conveyed to
the muscles; and the muscles act on this impulse, but their actions
are perverted.

Anomalous cases of convulsive affections have been designated by the
term Shaking Palsy: a term which appears to be improperly applied to
these cases, independent of the want of accordance between them and
that disease which has been here denominated Shaking Palsy. Dr.
Kirkland, in his commentary on Apoplectic and Paralytic Affections,
&c. cites the following case, related by Dr. Charlton, as belonging,
he says, to the class of Shaking Palsies. "Mary Ford, of a sanguineous
and robust constitution, had an involuntary motion of her right arm,
occasioned by a fright, which first brought on convulsion fits, and
most excruciating pain in the stomach, which vanished on a sudden, and
her right arm was instantaneously flung into an involuntary and
perpetual motion, like the swing of a pendulum, raising the hand, at
every vibration higher than her head; but if by any means whatever it
was stopped; the pain in her stomach came on again, and convulsion
fits were the certain consequence, which went off when the vibration
of her hand returned."

Another case, which the Doctor de