en the swelling
should be stimulated with a sharp cantharides blister, repeated, if the
case demands it, at intervals of a few days.

Should the swelling show distinct signs of pointing, and an abscess is
plainly the condition to be dealt with, its contents should be liberated by
a free use of the knife. In this connection it is important to insist on
the fact that the opening should be made large enough. One bold incision
from the uppermost limit of the swelling down to the coronary margin of the
wall is usually sufficient.

Even when pointing is not very evident, and suppuration is plainly more or
less diffuse, benefit may still be derived from the use of the knife. In
this case a deep scarification of the part is indicated. Three, four, or
more vertical incisions are made in the swelling, and from them obtained a
flow of blood mingled with a small quantity of pus from several different
centres. By this means sloughing of the diseased portion is quickly
obtained, and nothing but an ordinary open wound left for treatment. It
should be mentioned, however, that when sloughing can be in any way induced
to take place naturally it is better to allow this to take place. Even when
the necrosed portion is freely movable, and only adherent by its base, it
should not be forcibly removed, but left to the slower but more effectual
action of the tissue reactions. If torn forcibly away, we in all
probability leave in the bottom of the wound remnants of the dead tissue,
which, being small and consequently less productive of inflammatory
phenomena, are not so readily sloughed as the larger portion. These remain
as centres of infection, and prolong the case.

Once a suitable slough has occurred, the after-treatment is simple. It
consists in dressing the wound with reliable antiseptics, and maintaining
the parts in a healthy condition until Nature completes the cure by
repairing the breach. Solutions of carbolic acid, of perchloride of
mercury, of zinc chloride, or of moderately strong solutions of copper
sulphate, are all of them useful (see also treatment of coronitis on p.
236).

It is sometimes found that even with careful attention the wound left
by the removal of the slough shows a marked disinclination to heal. The
greater portion of the cavity becomes filled with granulation tissue, and
the epidermis gradually closes round until all is covered except a spot of
perhaps the size of half a crown or a crown piece. Here the regene