one or two degrees. There is swelling and
tenderness along the line of the affected vein, and the skin over it is
a dull-red or purple colour. The swollen vein may be felt as a firm
cord, with bead-like enlargements in the position of the valves. The
patient experiences a feeling of stiffness and tightness throughout the
limb. There is often oedema of the leg and foot, especially when the limb
is in the dependent position. The acute symptoms pass off in a few days,
but the swelling and tenderness of the vein and the oedema of the limb
may last for many weeks.

When the deep veins--iliac, femoral, popliteal--are involved, there is
great swelling of the whole limb, which is of a firm almost "wooden"
consistence, and of a pale-white colour; the oedema may be so great that
it is impossible to feel the affected vein until the swelling has
subsided. This is most often seen in puerperal women, and is known as
_phlegmasia alba dolens_.

_Treatment._--The patient must be placed at absolute rest, with the foot
of the bed raised on blocks 10 or 12 inches high, and the limb
immobilised by sand-bags or splints. It is necessary to avoid handling
the parts, lest the clot be displaced and embolism occur. To avoid
frequent movement of the limb, the necessary dressings should be kept in
position by means of a many-tailed rather than a roller bandage.

To relieve the pain, warm fomentations or lead and opium lotion should
be applied. Later, ichthyol-glycerin, or glycerin and belladonna, may be
substituted.

When, at the end of three weeks, the danger of embolism is past,
douching and gentle massage may be employed to disperse the oedema; and
when the patient gets up he should wear a supporting elastic bandage.

The _infective_ form usually begins as a peri-phlebitis arising in
connection with some focus of infection in the adjacent tissues. The
elements of the vessel wall are destroyed by suppuration, and the
thrombus in its lumen becomes infected with pyogenic bacteria and
undergoes softening.

_Occlusion of the inferior vena cava_ as a result of infective
thrombosis is a well-known condition, the thrombosis extending into the
main trunk from some of its tributaries, either from the femoral or
iliac veins below or from the hepatic veins above.

Portions of the softened thrombus are liable to become detached and to
enter the circulating blood, in which they are carried as emboli. These
may lodge in distant parts, and give rise to