kingdoms to prosperity; or discover and improve the sciences, which
meliorate and adorn the condition of humanity.

* * * * *

SECT. XI.

ADDITIONAL OBSERVATIONS ON THE SENSORIAL POWERS.

I. _Stimulation is of various kinds adapted to the organs of sense, to
the muscles, to hollow membranes, and glands. Some objects irritate our
senses by repeated impulses._ II. 1. _Sensation and volition frequently
affect the whole sensorium._ 2. _Emotions, passions, appetites._ 3.
_Origin of desire and aversion. Criterion of voluntary actions,
difference of brutes and men._ 4. _Sensibility and voluntarity._ III.
_Associations formed before nativity, irritative motions mistaken for
officiated ones._

_Irritation._

I. The various organs of sense require various kinds of stimulation to
excite them into action; the particles of light penetrate the cornea and
humours of the eye, and then irritate the naked retina; rapid particles,
dissolved or diffused in water or saliva, and odorous ones, mixed or
combined with the air, irritate the extremities of the nerves of taste and
smell; which either penetrate, or are expanded on the membranes of the
tongue and nostrils; the auditory nerves are stimulated by the vibrations
of the atmosphere communicated by means of the tympanum and of the fluid,
whether of air or of water, behind it; and the nerves of touch by the
hardness of surrounding bodies, though the cuticle is interposed between