268 



THE PATHOGENIC FLAGELLATES 



of 100 per cent. According to Bruce ('05) the disease is rapidly spread- 

 ing, now that Africa is being opened up. In regard to this he says : 

 "This sleeping sickness, which occurs on the west coast of Africa, 

 particularly in the basin of the Congo, has within the last few years 

 spread eastward into Uganda, has already swept off some hundreds 

 of thousands of victims, is spreading down the Nile, has spread all 

 around the shores of Lake Victoria, and is still spreading southward 

 around lakes Albert and Albert Edward." (Science, 1905, vol. xxii, 

 p. 298.) 



Just how the ill effects are produced is not known. There is evi- 

 dence, supported by the facts of acquired immunity in other forms, 

 that a toxin is produced causing more or less chronic inflammation, 

 or rapid destruction of erythrocytes. In man it produces a gradually 

 increasing lethargy, with mental and physical degeneration, rapid pulse, 

 increasing emaciation, all finally resulting in marked drowsiness, which 

 passes into a state of coma ending with death (Fig. 105). Mott ('99) 



FtG. 105 



Sleeping sickness; shortly before death. 



explained the lethargy as due to the action of some toxin, probably 

 of microorganism derivation, in the cerebrospinal fluid and acting 

 on the neurons. Bruce regards the disease as essentially "a disease of 

 the lymphatic system, and the irritation and proliferation of the lym- 

 phocytes is probably due to a toxin secreted by, or contained in, the 

 bodies of the trypanosomes. The characteristic symptoms of the 

 disease are, no doubt, due to the accumulations of these lymphocytes 

 in the perivascular spaces of the brain, compressing the arteries and 

 so interfering with the normal nutrition of the brain cells." (Bruce, 

 1907, p. 483.) 



It is still too early to speak of a cure for human trypanosomiasis, 

 and it is outside the limits of this work to enter into a discussion of the 

 various attempts that have been made to cure. The preliminary 

 success with atoxyl, alone or in combination with other salts, gives 

 reason to expect an ultimate control over the disease. 



