pleasure or pain, with which they were formerly accompanied.

3. But as the efforts of the will frequently accompanied these painful or
pleasureable sensations, by habit the fibrous contractions became causable
by volition; and both the irritations and sensations ceased to be necessary
to their production. As the deliberate locomotions of the body, and the
ideas of recollection, as when we will to repeat the alphabet backwards.

4. But as many of these fibrous contractions frequently accompanied other
fibrous contractions, by habit they became causable by their associations
with them; and the irritations, sensations, and volition, ceased to be
necessary to their production. As the actions of the muscles of the lower
limbs in fencing are associated with those of the arms; and the ideas of
suggestion are associated with other ideas, which precede or accompany
them; as in repeating carelessly the alphabet in its usual order after
having began it.

II. We shall give the following names to these four classes of fibrous
motions, and subjoin their definitions.

1. Irritative motions. That exertion or change of the sensorium, which is
caused by the appulses of external bodies, either simply subsides, or is
succeeded by sensation, or it produces fibrous motions; it is termed
irritation, and irritative motions are those contractions of the muscular
fibres, or of the organs of sense, that are immediately consequent to this
exertion or change of the sensorium.

2. Sensitive motions. That exertion or change of the sensorium, which
constitutes pleasure or pain, either simply subsides, or is succeeded by
volition, or it produces fibrous motions; it is termed sensation, and the