The Protozoa 



145 



West Africa. Those living on wooded shores of lakes and rivers, such 

 as fishermen and canoe men, are subject to it. The parasite is carried 

 by the bite of the tsetse fly (glossina palpalis). Wherever this insect 

 is found the disease is likely to prevail. The fly lives on bushes on the 

 shores of lakes or river banks, and feeds on the blood of crocodiles, 

 antelopes, etc. The trypanosomes undergo various changes in the body 

 of the fly. The infectivity does not appear until the thirty-second day, 

 but continues for at least seventy-five days. 



The parasite is found mostly in the cerebro-spinal fluid and 

 less commonly in the blood. Hope of exterminating the disease seems 

 to lie in exterminating the game (crocodiles especially) on which the 

 tsetse fly feeds. 



FLAGELLATES OF UNCERTAIN POSITION. (Fig. 58.) 



5 6 7 



Fig. 58. 

 Kala-Azar organism. 1, from a patient in India; 2 and 3, individual flagellate, 

 (Leishmania Jonovani) ; 4, 5, 6 and 7, Leishmania infantum. (From Kolle- 

 Wassermann.) 



Leishmania donovani. 

 Leishmania infantum. 

 Leishmania tropica. 



Causes Indian Kala Azar (dum-dum fever), Infantile Kala Azar, 

 and tropical boil, respectively. Common in Asia. Causes lesions on 

 exposed surfaces of body, enlargement of the spleen, and anaemia. 



The bed-bug or a blood-sucking bug is 

 probably the common carrier because ingested para- 

 sites undergoing development into flagellate forms 

 have been found in the bed-bug. 



The infantile disease affects children only ; 

 probably through dog fleas, as dogs are spon- 

 taneously infected in the epidermic regions. 

 Class IV. Infusoria. 



Balantidium coli (or Entamoeba coli). 

 (Fig. 59.) 

 Fig. 59. A ciliated, oval-shaped infusorian with a 



Balantidium coli, from i„„i_„j i j i • i 



an ulcer of man's intes- bean-shaped marco-nucleus and a spherical micro- 

 Luhe.) (After Braun and nucleus. The organisms frequently exhibit changes 



