622 TRYPANOSOMIASIS 



lymphocytosis in which the percentage of both the large and 

 small mononuclear cells is increased, so that the former may 

 constitute from 20 to 30 and the latter from 30 to 40 per cent, 

 of all the white cells present. As the disease progresses the 

 drowsiness increases till it deepens into a coma from which the 

 individual cannot be roused. Often during the disease there 

 occur irregular cedematous patches on the skin, and sometimes 

 erythematous eruptions, and effusions into the serous cavities. 

 Not every case runs a progressively advancing course. Some- 

 times along with enlargement of glands the chief early feature 

 is the occurrence from time to time of attacks of fever which 

 may be mistaken for malaria, and from these apparently com- 

 plete recovery may take place ; recurrence, however, follows as 

 a rule, and ultimately the typical terminal phenomena may 

 commence. Such cases may go on for years, and it is probable 

 that many patients die of pneumonia without exhibiting typical 

 manifestations of the malady from which they really suffer. 

 The disease is an extremely fatal condition, and probably no 

 case where the actual lethargy is developed ever recovers. 



On considering the disease from the standpoint of pathological 

 anatomy there is little to be said. As Mott described, the most 

 striking feature is the presence of a chronic meningo-encephalitis 

 and meningo-myelitis. The pia-arachnoid is sometimes opaque 

 and slightly thickened and may be adherent to the brain, and 

 its vessels usually show some congestion. The sub-arachnoid 

 fluid is sometimes in excess and occasionally may even be puru- 

 lent. 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 are related to the sub- 

 arachnoid space and the perivascular lymph spaces, with 

 accumulation and probably proliferation of lymphocytes in the 

 meshwork. He further points out that the changes in the 

 lymph glands are of similar nature and resemble the infiltration 

 of the perivascular lymphatics of the central nervous system. 

 These changes are specially significant in view of the lympho- 

 cytosis 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 of the 

 nerve cells, a diminution of Nissl's granules, and an excentricity 

 of the nucleus. 



