tends to burrow on to the chest wall beneath the pectoral muscles, and
upwards towards the shoulder-joint, which may become infected. When the
pus forms in the axillary space, the treatment consists in making free
incisions, which should be placed on the thoracic side of the axilla to
avoid the axillary vessels and nerves. If the pus spreads on to the
chest wall, the abscess should be opened below the clavicle by Hilton's
method, and a counter opening may be made in the axilla.

Cellulitis of the _sole of the foot_ may follow whitlow of the toes.

In the _region of the ankle_ cellulitis is not common; but _around the
knee_ it frequently occurs in relation to the prepatellar bursa and to
the popliteal lymph glands, and may endanger the knee-joint. It is also
met with in the _groin_ following on inflammation and suppuration of the
inguinal glands, and cases are recorded in which the sloughing process
has implicated the femoral vessels and led to secondary hæmorrhage.

Cellulitis of the scalp, orbit, neck, pelvis, and perineum will be
considered with the diseases of these regions.


CHRONIC SUPPURATION

While it is true that a chronic pyogenic abscess is sometimes met
with--for example, in the breast and in the marrow of long bones--in the
great majority of instances the formation of a chronic or cold abscess
is the result of the action of the tubercle bacillus. It is therefore
more convenient to study this form of suppuration with tuberculosis
(p. 139).