trolled by pressing in a
direction backward and slightly upward against the brim of the pelvis,
midway between the symphysis pubis and the anterior superior iliac
spine.

The abdominal aorta may be compressed against the bodies of the lumbar
vertebrae opposite the umbilicus, if the spine is arched well forwards
over a pillow or sand-bag, or by the method suggested by Macewen, in
which the patient's spine is arched forwards by allowing the lower
extremities and pelvis to hang over the end of the table, while the
assistant, standing on a stool, applies his closed fist over the
abdominal aorta and compresses it against the vertebral column.
Momburg recommends an elastic cord wound round the body between the
iliac crest and the lower border of the ribs, but this procedure has
caused serious damage to the intestine.

When digital compression is not available, the most convenient and
certain means of preventing haemorrhage--say in an amputation--is by the
use of some form of _tourniquet_, such as the elastic tube of Esmarch or
of Foulis, or an elastic bandage, or the screw tourniquet of Petit.
Before applying any of these it is advisable to empty the limb of blood.
This is best done after the manner suggested by Lister: the limb is held
vertical for three or four minutes; the veins are thus emptied by
gravitation, and they collapse, and as a physiological result of this
the arteries reflexly contract, so that the quantity of blood entering
the limb is reduced to a minimum. With the limb still elevated the
tourniquet is firmly applied, a part being selected where the vessel can
be pressed directly against a bone, and where there is no risk of
exerting injurious pressure on the nerve-trunks. The tourniquet should
be applied over several layers of gauze or lint to protect the skin, and
the first turn of the tourniquet must be rapidly and tightly applied to
arrest completely the arterial flow, otherwise the veins only are
obstructed and the limb becomes congested. In the lower extremity the
best place to apply a tourniquet is the middle third of the thigh; in
the upper extremity, in the middle of the arm. A tourniquet should never
be applied tighter or left on longer than is absolutely necessary.

The screw tourniquet of Petit is to be preferred when it is desired to
intermit the flow through the main artery as in operations for aneurysm.

When a tourniquet cannot conveniently be applied, or when its presence
interferes with