^"^l] THE TRYPANOSOMES 293 



REFERENCES. 



Austen, E. (1903). Monograph of the Tsetse-Flies, p. 95. 



(igii). Handbook of the Tsetse-Flies, -p. Ss- 



Davey, J. B. (1910). Bull. Entom. Research, vol. i. p. 143. 

 Koch, R. (1905). Deutsche Med. Wochenschr. vol. xxxi. Nov. 23. 

 Milne, A. D. (1910). S. S. Bulletin, vol. 11. p. 37. 



Neave, S. A. (1912). Bull. Entom. Research, vol. iii. p. 275. 

 Newstead, R. (1910). Ann. Trop. Med. and Parasit. vol. vi. p. 372. 

 Ross, P. H. (1908). Colonial Report East African Protectorate, No. 6490. 



(1910). Nairobi Laboratory Reports, vol. i. 



Sanderson, M. (1911). Bull. Entom. Research, vol. i. p. 292. 

 Stuhlmann, F. (1907). Arb. Kais. Gesimdheitsamte , vol. xxvi. p. 301. 



CHAPTER XVII 



GLOSSINA AND DISEASE 



THE TRYPANOSOMES 



Diagnosis, etc. The trypanosomes constitute a well-defined 

 group of flagellates inhabiting the blood of vertebrates, and 

 with few exceptions the known pathogenic species are mainly 

 transmitted by various species of Glossina. As many of them 

 are carried by more than one kind of tsetse-fly, it will be 

 convenient to discuss them collectively, instead of describing 

 each trypanosome separately under the heading of one of its 

 carriers. 



The genus Trypanosoma includes all those flagellates 

 characterised by the possession of a more or less elongated 

 fusiform body and a single anterior flagellum, which, at least 

 during some part of the hfe-cycle, arises near the posterior end 

 of the body, and for the greater part of its length is attached 

 to a fold of the periplast, known as the undulating membrane. 

 Occasionally the flagellum does not become free anteriorly but 

 is attached to the undulating membrane along its whole length. 



The dimensions of different species, or even of different 

 stages of the same species, may range from as small as 12 

 microns in length by 1-5 microns in breadth, up to more than 



