over the whole extent of the
tumour, sometimes only over a limited area. Frequently the margin only
is of a bright-red colour, while the skin in the centre resembles a
cicatrix. The swelling is reduced by steady pressure, and increases in
size and becomes tense when the child cries.

[Illustration: FIG. 68.--Mixed Naevus of Nose which was subsequently
cured by Electrolysis.]

_Prognosis._--The rate of growth of the subcutaneous and mixed forms of
naevi varies greatly. They sometimes increase rapidly, especially during
the first few months of life; after this they usually grow at the same
rate as the child, or more slowly. There is a decided tendency to
disappearance of these varieties, fully 50 per cent. undergoing natural
cure by a process of obliteration, similar to the obliteration of
vessels in cicatricial tissue. This usually begins about the period of
the first dentition, sometimes at the second dentition, and sometimes at
puberty. On the other hand, an increased activity of growth may be shown
at these periods. The onset of natural cure is recognised by the tumour
becoming firmer and less compressible, and, in the mixed variety, by the
colour becoming less bright. Injury, infection, or ulceration of the
overlying skin may initiate the curative process.

Towards adult life the spaces in a subcutaneous naevus may become greatly
enlarged, leading to the formation of a cavernous angioma.

_Treatment._--In view of the frequency with which subcutaneous and mixed
naevi disappear spontaneously, interference is only called for when the
growth of the tumour is out of proportion to that of the child, or when,
from its situation--for example in the vicinity of the eye--any marked
increase in its size would render it less amenable to treatment.

The methods of treatment most generally applicable are the use of radium
and carbon dioxide snow, igni-puncture, electrolysis, and excision.

For naevi situated on exposed parts, where it is desirable to avoid a
scar, the use of _radium_ is to be preferred. The tube of radium is
applied at intervals to different parts of the naevus, the duration and
frequency of the applications varying with the strength of the
emanations and the reaction produced. The object aimed at is to induce
obliteration of the naevoid tissue by cicatricial contraction without
destroying the overlying skin. _Carbon-dioxide snow_ may be employed in
the same manner, but the results are inferior to those obta