can have no other inducement to move its limbs but the taedium or
irksomeness of a continued posture.

The following case evinces, that the motions of stretching the limbs after
a continued attitude are not always owing to the power of the will. Mr.
Dean, a mason, of Austry in Leicestershire, had the spine of the third
vertebra of the back enlarged; in some weeks his lower extremities became
feeble, and at length quite paralytic: neither the pain of blisters, the
heat of fomentations, nor the utmost efforts of the will could produce the
least motion in these limbs; yet twice or thrice a day for many months his
feet, legs, and thighs, were affected for many minutes with forceable
stretchings, attended with the sensation of fatigue; and he at length
recovered the use of his limbs, though the spine continued protuberant. The
same circumstance is frequently seen in a less degree in the common
hemiplagia; and when this happens, I have believed repeated and strong
shocks of electricity to have been of great advantage.

4. In like manner the various organs of sense are originally excited into
motion by various external stimuli adapted to this purpose, which motions
are termed perceptions or ideas; and many of these motions during our
waking hours are excited by perpetual irritation, as those of the organs of
hearing and of touch. The former by the constant low indistinct noises that
murmur around us, and the latter by the weight of our bodies on the parts
which support them; and by the unceasing variations of the heat, moisture,
and pressure of the atmosphere; and these sensual motions, precisely as the
muscular ones above mentioned, obey their correspondent irritations without
our attention or consciousness.

5. Other classes of our ideas are more frequently excited by our sensations
of pleasure or pain, and others by volition: but that these have all been
originally excited by stimuli from external objects, and only vary in their
combinations or reparations, has been fully evinced by Mr. Locke: and are
by him termed the ideas of perception in contradistinction to those, which
he calls the ideas of reflection.

II. 1. These muscular motions, that are excited by perpetual irritation,
are nevertheless occasionally excitable by the sensations of pleasure or
pain, or by volition; as appears by the palpitation of the heart from fear,
the increased secretion of saliva at the sight of agreeable food, and the
glow on the skin of th