322 EASTERN ETHIOPIA xxvi 



Usoga and aloiio- the east side of the lake to Kisuniu. 

 It spread to, and practically depo2:)ulated, the islands of 

 the Sesse and the Buvuma Archipelagoes, and the 

 lacustrine districts in the C4erman sphere of interest. 

 In Uganda it is very prevalent and no age is exempt. 

 Race plays no important part, for many Europeans 

 have contracted the disease. 



For a long time Sleeping Sickness baffled all attempts 

 to determine its cause, but in 1902 Castellani examined 

 the cerebro-spinal liuid from patients with this disease 

 for organisms and detected the presence of trypano- 

 somes in this fluid. This discovery was confirmed by 

 Sir David Bruce, and Drs. Nabarro and Greig. 



The trypanosome is a protozoan parasitic in the blood 

 of vertel)rate animals. It lives freely in the serum of 

 the blood, never within or attached to blood corpuscles, 

 and possesses an undulating membrane which runs 

 down one side of its more or less spindle-shaped body. 

 At, or near, one extremity of the trypanosome is placed 

 the blepharoplast, and from this structure, or in its 

 immediate vicinity, the ilagellum takes origin and runs 

 along the free edge of the undulating membrane to 

 the opposite end of the body, where it continues its 

 course as a free Ilagellum. 



When these parasites oljtain an entrance into the 

 liodies of men, certain mammals, and birds, they 

 flourish, multiply, and, certainly in the case of man, 

 disturb the health : in the majority of instances tliey 

 destroy life. Infection by these parasites is termed 

 trypanosondasis. So far as we know the chief disease 

 resulting from their presence in the blood of man is 

 known as Sleeping Sickness, or Negro Lethargy. The 

 Baoanda call the disease Kubongota " to nod." The 

 species more j^articularly connected with man is known 

 as 2\ (jamhiense. When these parasites colonise the blood 

 they are carried in this medium through the " natural 

 gates and alleys of the body" so that when blood is 

 extracted either from the trunk, the tip of the toe, finger, 



