s of Gelatin._--Three or four ounces of a 2 per
cent. solution of white gelatin in sterilised water, at a temperature of
about 100 F., are injected into the subcutaneous tissue of the abdomen
every two, three, or four days. In the course of a fortnight or three
weeks improvement may begin. The clot which forms is liable to soften
and be absorbed, but a repetition of the injection has in several cases
established a permanent cure.

_Amputation of the limb_ is indicated in cases complicated by
suppuration, by secondary haemorrhage after excision or ligation, or by
gangrene. Amputation at the shoulder was performed by Fergusson in a
case of subclavian aneurysm, as a means of arresting the blood-flow
through the sac.

TRAUMATIC ANEURYSM

The essential feature of a traumatic aneurysm is that it is produced by
some form of injury which divides all the coats of the artery. The walls
of the injured vessel are presumably healthy, but they form no part of
the sac of the aneurysm. The sac consists of the condensed and thickened
tissues around the artery.

The injury to the artery may be a subcutaneous one such as a tear by a
fragment of bone: much more commonly it is a punctured wound from a stab
or from a bullet.

The aneurysm usually forms soon after the injury is inflicted; the blood
slowly escapes into the surrounding tissues, gradually displacing and
condensing them, until they form a sac enclosing the effused blood.

Less frequently a traumatic aneurysm forms some considerable time after
the injury, from gradual stretching of the fibrous cicatrix by which the
wound in the wall of the artery has been closed. The gradual stretching
of this cicatrix results in condensation of the surrounding structures
which form the sac, on the inner aspect of which laminated clot is
deposited.

A traumatic aneurysm is almost always sacculated, and, so long as it
remains circumscribed, has the same characters as a pathological
sacculated aneurysm, with the addition that there is a scar in the
overlying skin. A traumatic aneurysm is liable to become diffuse--a
change which, although attended with considerable risk of gangrene, has
sometimes been the means of bringing about a cure.

The treatment is governed by the same principles as apply to the
pathological varieties, but as the walls of the artery are not diseased,
operative measures dealing with the sac and the adjacent segment of the
affected artery are to be preferred.

ART