in proportion to the energy of the
volition that excites them, and the quantity of sensorial power.

II. 1. The muscular motions above described, that are most frequently
obedient to the will are nevertheless occasionally causable by painful or
pleasurable sensation, as in the starting from fear, and the contraction of
the calf of the leg in the cramp.

2. In like manner the sensual motions, or ideas, that are most frequently
connected with volition, are nevertheless occasionally causable by painful
or pleasurable sensation. As the histories of men, or the description of
places, which we have voluntarily taken pains to remember, sometimes occur
to us in our dreams.

III. 1. The muscular motions that are generally subservient to volition,
are also occasionally causable by irritation, as in stretching the limbs
after sleep, and yawning. In this manner a contraction of the arm is
produced by passing the electric fluid from the Leyden phial along its
muscles; and that even though the limb is paralytic. The sudden motion of
the arm produces a disagreeable sensation in the joint, but the muscles
seem to be brought into action simply by irritation.

2. The ideas, that are generally subservient to the will, are in like
manner occasionally excited by irritation; as when we view again an object,
we have before well studied, and often recollected.

IV. 1. Innumerable trains or tribes of motions are associated with these
voluntary muscular motions above mentioned; as when I will to extend my arm
to a distant object, some other muscles are brought into action, and
preserve the balance of my body. And when I wish to perform any steady
exertion, as in threading a needle, or chopping with an ax, the pectoral
muscles are at the same time brought into action to preserve the trunk of
the body motionless, and we cease to respire for a time.

2. In like manner the voluntary sensual motions, or ideas of recollection,
are associated with many other trains or tribes of ideas. As when I
voluntarily recollect a gothic window, that I saw some time ago, the whole
front of the cathedral occurs to me at the same time.

* * * * *

SECT. X.

OF ASSOCIATE MOTIONS.

I. 1. _Many muscular motions excited by irritations in trains or tribes
become associated._ 2. _And many ideas._ II. 1. _Many sensitive
muscular motions become associated._ 2. _And many sensitive ideas._
III. 1. _Many voluntary muscul