the carrying out of the operation--as, for example, in
amputations at the hip or shoulder--the haemorrhage may be controlled by
preliminary ligation of the main artery above the seat of operation--for
instance, the external iliac or the subclavian. For such contingencies
also the steel skewers used by Spence and Wyeth, or a special clamp or
forceps, such as that suggested by Lynn Thomas, may be employed. In the
case of vessels which it is undesirable to occlude permanently, such as
the common carotid, the temporary application of a ligature or clamp is
useful.

#Arrest of Haemorrhage.#--_Ligature._--This is the best means of securing
the larger vessels. The divided vessel having been caught with forceps
as near to its cut end as possible, a ligature of catgut or silk is tied
round it. When there is difficulty in applying a ligature securely, for
example in a dense tissue like the scalp or periosteum, or in a friable
tissue like the thyreoid gland or the mesentery, a stitch should be
passed so as to surround the bleeding vessel a short distance from its
end, in this way ensuring a better hold and preventing the ligature from
slipping.

If the haemorrhage is from a partly divided vessel, this should be
completely cut across to enable its walls to contract and retract, and
to facilitate the application of forceps and ligatures.

_Torsion._--This method is seldom employed except for comparatively
small vessels, but it is applicable to even the largest arteries. In
employing torsion, the end of the vessel is caught with forceps, and the
terminal portion twisted round several times. The object is to tear the
inner and middle coats so that they curl up inside the lumen, while the
outer fibrous coat is twisted into a cord which occludes the end of the
vessel.

_Forci-pressure._--Bleeding from the smallest arteries and from
arterioles can usually be arrested by firmly squeezing them for a few
minutes with artery forceps. It is usually found that on the removal of
the forceps at the end of an operation no further haemorrhage takes
place. By the use of specially strong clamps, such as the angiotribes of
Doyen, large trunks may be occluded by pressure.

_Cautery._--The actual cautery or Paquelin's thermo-cautery is seldom
employed to arrest haemorrhage, but is frequently useful in preventing
it, as, for example, in the removal of piles, or in opening the bowel in
colostomy. It is used at a dull-red heat, which sears the divide