660 TRYPANOSOMIASIS 



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 to 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 Xissl's granules, and an excentricity 

 of the nucleus. 



Trypanosoma (jamhiense. — Before going further we must refer 

 to the observation of a trypanosome in the blood of persons not 

 evidently suffering from sleeping sickness. The first case of 

 this was recorded by Dutton in 1901, the patient being a 

 European then living at Bathurst on the Gambia. The progress 

 of the disease was here very slow, and was characterised by 

 general wasting and weakness, irregular rises of temperature, 

 local cedemas, congested areas of the skin, enlargement of spleen, 

 and increased frequency of pulse and respiration ; death occurred 

 a year after the case came under observation after an access of 

 fever, and a striking fact was the absence of any gross causal 

 lesion. During the time the patient was under observation 

 trypanosomes were repeatedly demonstrated in the peripheral 

 blood, and they also developed in the bodies of monkeys and 

 white rats inoculated with the blood. Pursuing further in- 

 quiries, Dutton and Todd demonstrated similar parasites in 

 other Europeans and in several natives in the Gambia region, 

 whilst about the same time Manson reported a case of the same 

 kind in the wife of a missionary on the Congo. It thus came 

 to be recognised that in man there occurred a disease having 

 characters somewhat resembling nagana and in which trypano- 



