of its exact dimensions arrived at. This is
carefully noted, and the horn of the wall for some little distance around
it then rasped down quite thin. Immediately over the sinus, and for a short
distance on either side of it, the horn is stripped away to the sensitive
structures. The cavity of the fistula is then opened up with a scalpel, and
every particle of diseased tissue removed with this instrument and a pair
of forceps. After-dressing consists simply in the application of suitable
antiseptics.

_When the Complication of Necrosed Tendon or Ligament exists_.--We may take
it as an axiom that wherever this exists, whether it is in the extensor
pedis, in the lateral ligaments of the joint, or in portions of the
flexors, all diseased structures should, where possible, be removed. This
is done either with a scalpel or with a curette.

When septic matter has gained the sheath of the perforans, and the
formation of pus therein is indicated by inflammatory swellings in the
hollow of the heel, it is sometimes advisable to lay the sheath open for 1
to 2 inches along the course of the tendons. This, if a fistula is present,
may be best done with a blunt-pointed bistoury, or with a cannulated
director and a scalpel. With the pus thus given exit, and an antiseptic
dressing regularly applied, the case sometimes ends in rapid resolution.
More often than not, however, it is found that the pus has been liberated
too late, and that it has gravitated in the sheath to the extent of
affecting the plantar aponeurosis. Or it may be, of course, that it was in
the plantar aponeurosis the disease commenced. Whichever may have been the
case, we have in the hollow of the heel one or more fistulous openings, or
an opening we have made ourselves, leading down to a necrosed portion of
the terminal expansion of the perforans.

In such cases we ourselves have derived benefit from a regular flushing
of the sinuses with a 1 in 2,000 solution of perchloride of mercury,
introduced by means of a glass syringe, followed later by flushing in the
same manner with a 1 in 40 solution of carbolic acid, the hollow of the
heel meanwhile being kept clean with an antiseptic pad and bandage, or by
liberal applications of an antiseptic powder.

The septic materials are in this way destroyed, and the wound heals without
further complication. We must admit, however, that the cure of the lesion
is generally at the expense of slight lameness, due, in all probability,