.

12. _Vertigo ebriosa._ Vertigo from intoxication is owing to the
association of the irritative ideas of vision with the irritative motions
of the stomach. Whence when these latter become much increased by the
immoderate stimulus of wine, the irritative motions of the retina are
produced with less energy by reverse sympathy, and become at the same time
succeeded by sensation in consequence of their decreased action. See Sect.
XXI. 3. and XXXV. 1. 2. So conversely when the irritative motions of vision
are increased by turning round, or by our unaccustomed agitation at sea,
those of the stomach become inverted by reverse sympathy, and are attended
in consequence with disagreeable sensation. Which decreased action of the
stomach is in consequence of the increased expenditure of the sensorial
power on the irritative ideas of vision, as explained in Vertigo rotatoria.

Whence though a certain quantity of vinous spirit stimulates the whole
system into increased action, and perhaps even increases the secretion of
sensorial power in the brain; yet as soon as any degree of vertigo is
produced, it is a proof, that by the too great expenditure of sensorial
power by the stomach, and its nearest associated motions, the more distant
ones, as those of vision, become imperfectly exerted. From hence may be
deduced the necessity of exhibiting wine in fevers with weak pulse in only
appropriated quantity; because if the least intoxication be induced, some
part of the system must act more feebly from the unnecessary expenditure of
sensorial power.

13. _Vertigo febriculosa._ Vertigo in fevers either proceeds from the
general deficiency of sensorial power belonging to the irritative
associations, or to a greater expenditure of it on some links of the trains
and tribes of associated irritative motions. There is however a slighter
vertigo attending all people, who have been long confined in bed, on their
first rising; owing to their having been so long unused to the apparent
motions of objects in their erect posture, or as they pass by them, that
they have lost in part the habit of balancing themselves by them.

14. _Vertigo cerebrosa._ Vertigo from injuries of the brain, either from
external violence, or which attend paralytic attacks, are owing to the
general deficiency of sensorial power. In these distressful situations the
vital motions, or those immediately necessary to life, claim their share of
sensorial power in the first place, ot