week later the threads
are removed and the minute punctures are sealed with collodion. The
action of the threads is to convert the cyst wall into granulation
tissue, which undergoes the usual conversion into scar tissue. If the
cyst re-forms, it should be removed by open dissection under local
anaesthesia. Puncture with a tenotomy knife and scraping the interior,
and the injection of irritants, are alternative, but less satisfactory,
methods of treatment.

_Ganglia_ in the substance of _tendons_ are rare. The diagnosis rests on
the observation that the small tumour is cystic, and that it follows the
movements of the tendon. The cyst is at first multiple, but the
partitions disappear, and the spaces are thrown into one. The tendon is
so weakened that it readily ruptures. The best treatment is to resect
the affected segment of tendon.

The so-called "compound palmar ganglion" is a tuberculous disease of the
tendon sheaths, and is described with diseases of tendon sheaths.

CHAPTER XI

INJURIES

CONTUSIONS--WOUNDS: _Varieties_--WOUNDS BY FIREARMS AND
EXPLOSIVES: _Pistol-shot wounds_; _Wounds by sporting guns_;
_Wounds by rifle bullets_; _Wounds received in warfare_; _Shell
wounds_. _Embedded foreign bodies_--BURNS AND
SCALDS--INJURIES PRODUCED BY ELECTRICITY: _X-ray and
radium_; _Electrical burns_; _Lightning stroke_.

CONTUSIONS

A contusion or bruise is a laceration of the subcutaneous soft tissues,
without solution of continuity of the skin. When the integument gives
way at the same time, a _contused-wound_ results. Bruising occurs when
force is applied to a part by means of a blunt object, whether as a
direct blow, a crush, or a grazing form of violence. If the force acts
at right angles to the part, it tends to produce localised lesions which
extend deeply; while, if it acts obliquely, it gives rise to lesions
which are more diffuse, but comparatively superficial. It is well to
remember that those who suffer from scurvy, or haemophilia (bleeders),
and fat and anaemic females, are liable to be bruised by comparatively
trivial injuries.

_Clinical Features._--The less severe forms of contusion are associated
with _ecchymosis_, numerous minute and discrete punctate haemorrhages
being scattered through the superficial layers of the skin, which is
slightly oedematous. The effused blood is soon reabsorbed.

The more severe forms are attended with _extravasation_, the
extravasated b