become torpid. As explained in
Sect. XVIII. 15. In respect to medicine, two drams of valerian root in
powder three or four times a day are recommended by Fordyce. The bark.
Steel in moderate quantities. An emetic. A blister. Opium, half a grain
twice a day. Decayed teeth should be extracted, particularly such as either
ache, or are useless. Cold bath between 60 and 70 degrees of heat. Warm
bath of 94 or 98 degrees every day for half an hour during a month. See
Class IV. 2. 2. 7. and 8.

A solution of arsenic, about the sixteenth part of a grain, is reported to
have great effect in this disease. It should be taken thrice a day, if it
produces no griping or sickness, for two or three weeks. A medicine of this
kind is sold under the name of tasteless ague-drops; but a more certain
method of ascertaining the quantity is delivered in the subsequent materia
medica, Art. IV. 2. 6.

12. _Odontalgia._ Tooth-ach. The pain has been erroneously supposed, where
there is no inflammation, to be owing to some acrid matter from a carious
tooth stimulating the membrane of the alveolar process into violent action
and consequent pain; but the effect seems to have been mistaken for the
cause, and the decay of the tooth to have been occasioned by the torpor and
consequent pain of the diseased membrane.

First, because the pain precedes the decay of the tooth in regard to time,
and is liable to recur, frequently for years, without certainly being
succeeded at last by a carious tooth, as I have repeatedly observed.

Secondly, because any stimulant drug, as pyrethrum, or oil of cloves,
applied to the tooth, or ether applied externally to the cheek, so far from
increasing the pain, as they would do if the pained membrane, already acted
too strongly, that they frequently give immediate relief like a charm.

And thirdly, because the torpor, or deficient action of the membrane, which
includes the diseased tooth, occasions the motions of the membranes most
connected with it, as those of the cheek and temples, to act with less than
their natural energy; and hence a coldness of the cheek is perceived easily
by the hand of the patient, comparing it with the other cheek; and the pain
of hemicrania is often produced in the temple of the affected side.

This coldness of the cheek in common tooth-ach evinces, that the pain is
not then caused by inflammation; because in all inflammations so much heat
is produced in the secretions of new vessels and flui