ACUTE HAEMORRHAGIC ENCEPHALITIS. 
101 
In the first four brains the meninges were perhaps somewhat 
congested, but there was no trace of inflammatory exudate. 
The brain, however, was not uniform in consistency and soft 
fluctuating areas could be felt. Section of the brains shows 
these fluctuating areas to correspond with cavities in the brain 
substance, filled with a softened pulpy greyish yellow mass of 
necrotic tissue and a glairy, somewhat opalescent fluid. The 
necrotic material is in large part mixed with dark blood, and 
there are very numerous haemorrhages in the adjacent brain tis¬ 
sue. If a section be made through ^uch an area after first hard¬ 
ening the brain in formalin, the fluid described is found to be 
coagulated into a gelatinous mass like agar, in which lie shreds 
and masses of greyish brain substance. The adjacent tissue is 
somewhat greyish and opaque for a distance of about three 
mm., and is studded with haemorrhages. In other such areas 
the greyish, opaque, crumbly brain substance shows only small 
bands of the gelatinous material, but in all cases the haemor¬ 
rhages are prominent. 
The blood vessels in the region of such foci were carefully 
traced, but no occlusion of their lumen could be found. 
The situation of the lesion varies—in one brain there were 
cavities symmetrically placed in the superior portion of the an¬ 
terior lobes of the cerebral hemispheres—in front of the motor 
region and above the lateral and olfactory ventricles, which 
show no obvious alterations. On one side the cavity measured 
about 1x2 cm.— on the other side about 5 cm. in diameter; 
they extend about to the line between the grey and white mat¬ 
ter of the cortex, leaving the grey matter as a sort of roof. In 
another brain there was a large cavity in the white substance of 
the anterior lobe and a second smaller one in the temporal lobe 
of the same size, while the opposite hemisphere showed no le¬ 
sion. A third case showed a lesion in the occipital lobe as well 
as in the anterior. 
Microscopically sections through such a lesion with the ad¬ 
jacent brain substance show a complete disappearance of nerv¬ 
ous elements in the immediate neighborhood of the cavity. 
