ined by
radium.

_Igni-puncture_ consists in making a number of punctures at different
parts of the naevus with a fine-pointed thermo-cautery, with the object
of starting at each point a process of cicatrisation which extends
throughout the naevoid tissue and so obliterates the vessels.

_Electrolysis_ acts by decomposing the blood and tissues into their
constituent elements--oxygen and acids appearing at the positive,
hydrogen and bases at the negative electrode. These substances and gases
being given off in a nascent condition, at once enter into new
combinations with anything in the vicinity with which they have a
chemical affinity. In the naevus the practical result of this reaction is
that at the positive pole nitric acid, and at the negative pole caustic
potash, both in a state of minute subdivision, make their appearance.
The effect on the tissues around the positive pole, therefore, is
equivalent to that of an acid cauterisation, and on those round the
negative pole, to an alkaline cauterisation.

As the process is painful, a general anaesthetic is necessary. The
current used should be from 20 to 80 milliamperes, gradually increasing
from zero, without shock; three to six large Bunsen cells give a
sufficient current, and no galvanometer is required. Steel needles,
insulated with vulcanite to within an eighth of an inch of their points,
are the best. Both poles are introduced into the naevus, the positive
being kept fixed at one spot, while the negative is moved about so as to
produce a number of different tracks of cauterisation. On no account
must either pole be allowed to come in contact with the skin, lest a
slough be formed. The duration of the sitting is determined by the
effect produced, as indicated by the hardening of the tumour, the
average duration being from fifteen to twenty minutes. If pallor of the
skin appears, it indicates that the needles are too near the surface, or
that the blood supply to the integument is being cut off, and is an
indication to stop. To cauterise the track and so prevent bleeding, the
needles should be slowly withdrawn while the current is flowing. When
the skin is reached the current is turned off. The punctures are covered
with collodion. Six or eight weeks should be allowed to elapse before
repeating the procedure. From two to eight or ten sittings may be
necessary, according to the size and character of the naevus.

_Excision_ is to be preferred for naevi of moderate