one or
through the temporal fossa, according to the site of the abscess and
its seat of origin. The primary focus of infection must also be dealt
with.

In _infected compound fractures_, an abscess may form in the cortical
grey matter within a few days of the injury from direct spread of
infection from the bone and membranes. This is usually associated with
a spreading lepto-meningitis, the symptoms of which predominate. The
condition usually proves fatal, but by opening up the original wound,
removing depressed fragments of bone, and establishing drainage, the
patient's life may be saved.

There is evidence that an abscess may form in the brain after a simple
contusion without fracture or other external injury (Ehrenvooth).

An abscess may develop in the white matter of the centrum ovale some
weeks, or even months, after an injury, particularly if a fragment of
bone or a foreign body has been driven into the brain. If the
infection has spread along the track of the missile, the abscess is
usually near to the seat of the brain injury, but if it is due to
spread of a thrombo-phlebitis it may be a considerable distance from
it, even on the opposite side of the head. These chronic abscesses are
usually in the parietal or frontal lobes, and as the pus is
encapsulated they may remain latent for long periods, during which
they may cause some degree of headache, neuralgic pains in the
distribution of the trigeminal nerve, and occasional rises of
temperature. When the abscess becomes active, general symptoms similar
to those of other forms of abscess develop, and there may be localised
paralysis of the opposite side of the body, the distribution of which
depends upon whether the cortical centres or the motor fibres are
implicated.

The treatment consists in opening up the original wound, removing any
depressed bone or foreign body that may be present, and establishing
drainage.

_Bronchiectasis_ and other infective diseases of the lungs are less
common causes of cerebral abscess, which is usually single, and may
occur in any part of the brain.

_Disease of the bones of the skull_, such as osteomyelitis or
syphilis, may be followed by cerebral abscess.

Abscesses of _pyaemic_ origin are usually multiple, and may occur both
in the cerebrum and in the cerebellum; they are not amenable to
surgical treatment.

SINUS PHLEBITIS

Inflammation of the intra-cranial venous sinuses is due to the spread
of infection from a l