an
attempt should be made, after exposing this, to purify and drain the
meningeal spaces. Temporary relief of symptoms sometimes follows the
withdrawal of cerebro-spinal fluid by repeated lumbar puncture,
bleeding by leeches or cupping, or the use of an ice-bag or Leiter's
tubes. The bowels should be freely moved by purgatives or enemata.

_Cerebro-spinal Meningitis._--This form of meningitis, which is due to
the _diplococcus intracellularis_, may occur sporadically, but is more
frequently met with in an epidemic form. It is attended with the
formation of a profuse sero-purulent exudate, which covers the brain,
the cord, the nerves, and the membranes.

The clinical features are similar to those of acute general
lepto-meningitis, and in sporadic cases the diagnosis is only
completed by discovering the diplococcus intracellularis in the fluid
withdrawn by lumbar puncture. Although recovery sometimes takes place,
the disease is attended with a high mortality. In the early stages,
before the exudate has become too thick, repeated lumbar puncture
followed by the injection of Flexner's serum has proved beneficial.
Recovery may be attended with paralysis of one or other of the cranial
nerves.

CEREBRAL AND CEREBELLAR ABSCESS

#Abscess due to Middle Ear Disease.#--The most common cause of abscess
in the brain is chronic middle ear disease, and the majority of
cerebral abscesses are therefore situated in the temporal lobe. Some
are due to direct spread from a collection of pus in relation to an
erosion of the tegmen tympani, either inside or outside the dura,
others to infection carried by the veins, and in this way the
infective material reaches the white matter; less frequently infection
from the middle ear takes place along the peri-vascular lymph spaces.
Macewen has pointed out that cerebral abscess never occurs from
pyogenic organisms passing from the middle ear by way of the internal
auditory meatus, although lepto-meningitis may do so. Cerebral abscess
is much more frequently met with in the white matter of the centrum
ovale than in the cortex, and in the majority of cases the abscess is
single.

The _pus_ is often of a greenish-yellow colour, or it may be dark
brown from admixture with broken-down blood-clot; in some cases it is
thin and serous and contains sloughs of brain matter, and it
frequently has a foetid odour. In quantity it varies from a few drops
to several ounces.

The _arachno-pia_ over an abscess