essary to their health as well as to their pleasure, that
those children, which are too much confined from it, not only become
pale-faced and bloated, with tumid bellies, and consequent worms, but are
liable to get habits of unnatural actions, as twitching of their limbs, or
of some parts of their countenance; together with an ill-humoured or
discontented mind.

Agitation in a carriage or on horseback, as it requires some little
voluntary exertion to preserve the body perpendicular, but much less
voluntary exertion than in walking, seems the best adapted to invalids; who
by these means obtain exercise principally by the strength of the horse,
and do not therefore too much exhaust their own sensorial power. The use of
friction with a brush or hand, for half an hour or longer morning and
evening, is still better adapted to those, who are reduced to extreme
debility; and none of their own sensorial power is thus expended, and
affords somewhat like the warm-bath activity without self-exertion, and is
used as a luxury after warm bathing in many parts of Asia.

Another kind of exercise is that of swinging, which requires some exertion
to keep the body perpendicular, or pointing towards the center of the
swing, but is at the same time attended with a degree of vertigo; and is
described in Class II. 1. 6. 7. IV. 2. 1. 10. Sup. I. 3. and 15.

The necessity of much exercise has perhaps been more insisted upon by
physicians, than nature seems to demand. Few animals exercise themselves so
as to induce visible sweat, unless urged to it by mankind, or by fear, or
hunger. And numbers of people in our market towns, of ladies particularly,
with small fortunes, live to old age in health, without any kind of
exercise of body, or much activity of mind.

In summer weak people cannot continue too long in the air, if it can be
done without fatigue; and in winter they should go out several times in a
day for a few minutes, using the cold air like a cold-bath, to invigorate
and render them more hardy.

III. CATALOGUE OF THE INCITANTIA.

I. Papaver somniferum; poppy, opium.

Alcohol, wine, beer, cyder.

Prunus lauro-cerasus; laurel, distilled water from the leaves.

Prunus cerasus; black cherry, distilled water from the kernels.

Nicotiana tabacum; tobacco? the essential oil, decoction of the leaf.

Atropa belladona; deadly nightshade, the berries.

Datura stramoneum; thorn-apple, the fruit boiled in milk.