MASTIGOPHORA 



1087 



now recognized as stages in one and the same infection, human tryp- 

 anosomiasis : they were trypanosome fever, and sleeping sickness. It 

 is a chronic infection characterized by fever, lassitude, weakness, 

 wasting, and, in its terminal stages, by a protracted lethargy. 

 Sleeping sickness and trypanosome fever had long been known in 

 tropical Africa, and the disease at present is widespread and the 



FIG. 139. TRYPANOSOMA AVIUM IN CULTURE ON BLOOD AGAR. (X1500). (After 

 Novy and MacNeal. MacNeal, " Pathogenic Microorganisms," published by 

 P. Blakiston's Son & Co.) 



cause of tremendous mortality. It is estimated that one hundred 

 thousand deaths occurred during the ten years ending in 1910. It 

 is endemic in the lake region of Central Africa, and in the Congo 

 basin. It was early introduced into Martinique in the West Indies, 

 but did not spread and has now died out. 



Button and Todd found the parasite in 1901 in the blood of an 

 Englishman in Gambia, who died after a febrile illness of two years' 



