TRYPANOSOMA OF SLEEPING SICKNESS 557 



The sub-arachnoid fluid is sometimes in excess and occasionally 

 may even be purulent. The membranes of the spinal cord 

 show similar changes. The chief other feature is the presence 

 of enlarged lymphatic glands in the body, but otherwise there is 

 nothing special to note. With regard to the microscopic 

 changes the chief feature, according to Mott, is a proliferation 

 and overgrowth of the neuroglia cells, especially of those which 



Fm. 169. Trypanosoma gambiense from blood of guinea-pig. x 1000. 



are related to the sub-arachnoid space and the perivascular lymph 

 spaces, with accumulation and probably proliferation of lympho- 

 cytes in the meshwork. He further points out that the changes 

 in the lymph glands are of similar nature and resemble the in- 

 filtration of the perivascular lymphatics of the central nervous 

 system. These changes are specially significant in view of the 

 lymph ocytosis present in the blood, which has already been 

 noted, and which so often occurs in protozoal infections. In the 

 nervous structures there is comparatively little change, there 

 being merely, according to Mott, some atrophy of the dendrons 



