THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
lymphocytes, phagocytes, with all kinds of inclusions, also a few larger mononuclear 
and polymorphonuclear leucocytes, and a large number of red blood corpuscles. The 
same infiltration was found about the cells of the pia and accompanying it into the 
cerebral sulci and to a certain extent into the brain cortex itself. In the brain the 
infiltration occurred chiefly around the vessels of the deeper parts of the brain, those 
of the cortex showing relatively slight changes. 
The vessels in the deeper parts were very large and congested, the perivascular 
lymph space dilated, sometimes empty, at other times occupied by coagulated exudation 
or filled with lymphocytes. The proliferated endothelium projected into the lumen. 
The vessels in the more deeply situated parts of the brain were much more changed, 
especially in the region of the large grey basal ganglia. Here the vessels were 
surrounded by a thick layer of lymphocytes, filling up the perivascular space and 
extending into the brain substance. Amongst the exuded lymphocytes there were a 
good number of red cells. There were also cells resembling granulation-tissue cells, 
hyaline with a vesicular nucleus ; large cells (thirty to fifty /u. in diameter) with 
protoplasm stained reddish with eosine and having one to three nuclei ; a few 
phagocytes and an occasional plasma cell. 
The lumina of the vessels were often narrowed. Close to the vessels were various 
sized haemorrhages without any lesions of the vessel wall. 
Very often, external to the layer of white cells which surrounded a vessel, was 
a second layer of red blood cells infiltrating the brain substance in the neighbourhood. 
In some places the brain was altogether destroyed through haemorrhage, but no blood 
pigment was seen, and red softening was marked. Around the infiltrated 
vessels was usually a proliferation of glia cells. The endothelium of the vessels was 
proliferated and the vessels contained many white blood corpuscles, sometimes in so 
large numbers that they seemed to fill the whole vessel like a thrombus. The infiltration 
was in general equally pronounced both around artery and vein, but sometimes the 
vein was more changed than the artery. 
Here, and in other sections, where the vessel was seen in tangential section, red 
corpuscles were present in the media and adventitia. The ependyma of the lateral 
ventricle was proliferated, forming a dense fibrous layer. 
The epithelial cells of the choroidal plexus approached the columnar in type and 
often had gaps between them. 
Similar changes to those in the cerebrum were found in the pons, medulla, and 
spinal cord. 
The pons on section appeared much congested, the vessels were irregularly sheathed 
with a layer of cells of the same nature as those above described ; the intervals between 
them being occupied by coagulated fluid. Throughout the section of the pons were 
seen various-sized haemorrhages ; the endothelium of the vessels was thickened, and 
there were a fair number of white blood cells in the lumen. Similar changes but 
