XVIII] MORPHOLOGY 349 



Kleine and Fischer, in the region of Lake Tanganyika, have 

 found both sheep and antelopes naturally infected with a try- 

 panosome that seems to agree with nanum in its characters. 



In cattle, T. nanum produces a disease which develops 

 slowly ; the main symptom is the well-marked anaemia, which is 

 accompanied by a gradual emaciation and usually ends in the 

 death of the infected animal. 



The parasites are usually present in the peripheral circula- 

 tion, sometimes in considerable numbers, and can be easily 

 recognised. 



T. nanum can readily be inoculated into cattle and goats, 

 but all the smaller laboratory animals are refractory to infec- 

 tion, for monkeys, dogs, rats and mice have been inoculated 

 without becoming infected. 



Morphology of the parasite. Laveran has given the following 

 diagnosis of Trypanosoma nanum : 



' The trypanosomes measure 10 to 14 ^ in length, by 1-5 

 to 2 ^ in breadth. Their structure is that of flagellates 

 belonging to the genus Trypanosoma ; yet, contrary to the 

 rule, the protoplasm is prolonged at the anterior end, in such a 

 manner that there is no free flagellum, or the free part of the 

 flagellum is extremely short. The undulating membrane is 

 very narrow and in consequence only slightly evident. The 

 posterior extremity is conical, not drawn out, otherwise a little 

 variable in form." 



" The oval nucleus is situated about the middle of the body 

 of the parasite. The centrosome (= kinetonucleus) , rounded 

 and rather large, is found almost at the posterior extremity. 

 ' The protoplasm is homogeneous, without granulations. 



" Some of the forms, a little larger than the others, shew 

 two centrosomes and a flagellum divided for a greater or lesser 

 extent from the origin in the centrosome ; these are evidently 

 multiplication forms." 



In Uganda the length of the parasite may extend up to 

 16 microns as shewn by Bruce, Hamerton, Bateman and Mackie, 

 and also by Duke. 



Mode of transmission. The experiments of Duke in Uganda 

 have shewn that Glossina palpalis may serve as the intermediate 



