res. Different forms of
aphasia and interference with vision or with hearing follow
implication of the centres governing these functions. In the
pre-frontal and in the lower temporal convolutions no special symptoms
seem to follow. When the haemorrhages are extensive and numerous,
symptoms of compression may ensue, and these are aggravated when
oedema of the brain is superadded.

Localised haemorrhages also occur, although less frequently, in the
crura cerebri, the pons, the floor of the fourth ventricle, and the
cerebellum. In these situations they usually prove fatal by causing
rapidly advancing coma and interference with the respiratory and
cardiac centres. The temperature immediately rises to 106 deg. or even
108 deg. F., and a modified form of Cheyne-Stokes respiration is present.

(3) Still more gross lesions, in the form of distinct _lacerations_,
are comparatively common at the tips of the frontal, temporal, and
occipital lobes, on the surface of the cerebellum, and at the base of
the brain. These are usually associated with symptoms of compression
in its most typical form, and as a rule prove fatal. The grey matter
is torn, and extensive effusion of blood takes place into the brain
substance, and on the surface, filling up the sulci, and distending
the arachno-pial space (Fig. 184). In a compound fracture, brain
matter may be extruded through the opening in the skull.

(4) The extravasated blood may burst _into the lateral ventricles_,
in which case the pulse becomes small and rapid--130, 160, or even
170. The respiration also is rapid--45 to 60--and greatly embarrassed,
and the temperature suddenly rises to 103 deg. or 104 deg. F., and continues
to rise till death ensues.

(5) _Traumatic Oedema._--It is not uncommon for a diffuse oedematous
infiltration of the brain substance or of the arachno-pial membrane to
take place in the vicinity of the injured portion of brain. This
serous exude, on account of the natural adhesions of the arachno-pia,
usually remains limited to the damaged area, but it may become
generalised.

_Mechanism._--The explanation of these widespread haemorrhages is to be
found, according to Duret, in the disturbance of the cerebro-spinal
fluid which accompanies a severe blow on the head. This fluid not only
surrounds the brain, but it also fills the ventricles, and permeates
its substance in every direction in the peri-vascular and
perilymphatic spaces. As the brain tissue is incompress