TRYPANOSOMA 67 



binary longitudinal fission by which reproduction takes place 

 is sometimes unequal. In fission, first the blepharoplast divides, 

 then the parabasal body, and finally the nucleus, while the flag- 

 ellum and membrane are doubled, but probably not by division. 

 During the progress of the infection some of the trypanosomes 

 pass into certain of the internal organs of their host, especially 

 into the spleen and lungs. There they lose their flagella and 

 become an oval shape. In this condition they show resemblances 



Fig. 39. — Trypanosoma gamhiense, 

 A stained preparation of the blood of an infected guinea-pig, showing blood corpuscles and parasites. 



to the predominant phase of the organism known as Leishmania, 

 which is the cause of the kala-azar disease and of Delhi boil. 

 True Leishmania stages, which presently revert to the flagellate 

 condition, do occur in the life-cycles of other trypanosomes. It 

 has been supposed that these phases of T. gamhiense are of a 

 similar nature and that they revert and thus make good the loss 

 of flagellates in the blood when, as happens between the fits 

 of the fever, the flagellates are reduced in number by the secretion 

 of ' antibodies ' (p. 151) by the host. On this theory they have 

 been called ' latent bodies '. It is more probable, however, that 

 thev are individuals in a state of degeneration. 



