excretion; those medicines, which promote absorption only, are more
advantageous for the healing an ulcer after it is filled with new flesh; as
the Peruvian bark internally; with bandages and solutions of lead
externally.

5. There are many pains which originate from a want of due motion in the
part, as those occasioned by cold; and all those pains which are attended
with cold extremities, and are generally termed nervous. These are relieved
by whatever excites the part into its proper actions, and hence by opium
and alcohol; which are the most universal stimulants we are acquainted
with. In these cases the effect of opium is produced, as soon as the body
becomes generally warm; and a degree of intoxication or sleep follows the
cessation of the pain.

These nervous pains (as they are called) frequently return at certain
periods of time, and are also frequently succeeded by convulsions; in these
cases if opium removes the pain, the convulsions do not come on. For this
purpose it is best to exhibit it gradually, as a grain every hour, or half
hour, till it intoxicates. Here it must be noted, that a much less quantity
will prevent the periods of these cold pains, than is necessary to relieve
them after their access. As a grain and half of opium given an hour before
the expected paroxysm will prevent the cold fit of an intermittent fever,
but will not soon remove it, when it is already formed. For in the former
case the usual or healthy associations or catenations of motion favour the
effect of the medicine; in the latter case these associations or
catenations are disordered, or interrupted, and new ones are formed, which
so far counteract the effect of the medicine.

When opium has been required in large doses to ease or prevent convulsions,
some have advised the patient to omit the use of wine, as a greater
quantity of opium might then be exhibited; and as opium seems to increase
absorption more, and secretion less, than vinous spirit; it may in some
cases be useful to exchange one for the other; as in diseases attended with
too great evacuation, as diarrhoea, and dysentery, opium may be preferable;
on the contrary in tetanus, or locked-jaw, where inflammation of the system
might be of service, wine may be preferable to opium; see Class III. 1. 1.
13. I have generally observed, that a mixture of spirit of wine and warm
water, given alternately with the doses of opium, has soonest and most
certainly produced that degree