33i 
Some of the brain tissue was sent to Dr. Mott, F.R.S., by 
Professor Ross for his opinion. The report given by Dr. Mott 
appears below: — 
Report on the Examination of Brain Tissue sent by Major R. Ross 
Two small portions of brain embedded in paraffin were 
received; one was a small piece of cerebellum; the other was a small 
portion of white subcortical tissue, location not definable. Sections 
of 5/< were cut and stained by polychrome, Giemsa and Heidenhain 
haematoxylin methods. 
All the sections examined showed a well-marked perivascular 
infiltration with lymphocytes and plasma cells, indistinguishable 
from that which I have seen in all cases of sleeping sickness. The 
membranes were absent in both pieces of tissue so I cannot say they 
were affected. Apparently there was evidence of glia hyperplasia 
and proliferation in the subcortical tissue. Inasmuch as 
subcortical and cerebellar tissues always show a more marked 
perivascular infiltration than the cortex in early cases it would have 
been more satisfactory if different regions of the cortex could have 
been examined. For unless the perivascular infiltration affects 
diffusely the cerebral cortex (seat of consciousness) one would not 
expect marked lethargy. From an examination of a large number 
of cases of sleeping sickness I have come to the conclusion that 
the subcortical structures are affected primarily and that there is a 
parallelism between the depth of the lethargy and the intensity an 
diffuseness of affection of the meninges and cortical vessels wit 
neuroglia proliferation and changes in the nerve cells. A large 
number of the vessels show fibrin filaments indicative o 
pneumonic condition. 
