43 



results in two unequal individuals, and is therefore more 

 like the budding of a smaller daughter individual from 

 the larger parent. Further division of both results in an 

 aggregate of individuals (the parent always distinct) which 

 remain for a time grouped side by side in a ring, their 

 non-flagellate ends towards the centre. That kind of fission 

 seems to be intermediate between ordinary equal division 

 and another kind, called segmentation by rosette formation, 

 which is also characteristic of T. lewisi. The process is 

 as follows : the double nucleus divides into a number 

 of small double nuclei ; the body cytoplasm having been 

 rounded, the paired nuclei move to the periphery which 

 now becomes lobulated ; the splits are extended inwards 

 and the lobes thus become distinct segments or daughter 

 trypanosomes (each with a trophonucleus, a kinetonucleus 

 and a flagellum) ; they remain for a time connected to- 

 gether at the centre. In this way a rosette of small equal- 

 sized .Trypanosomes is formed and the identity of the 

 parent lost. 



What is the Importance of Trypanosoma Gambiense and 

 Trypanosoma Rhodesiense ? 



They are internal parasites in the blood of Man. The 

 presence of T. gambiense in the blood is the cause of Try- 

 panosome Fever (in West and Central Africa). When, 

 at a later stage, it occurs in the cerebro-spinal fluid, it 

 causes the deadly malady known as " Sleeping Sickness." 

 T. rhodesiense causes a form of " sleeping sickness " in 

 Nyassaland and North-east Rhodesia. 



How are Trypanosoma Gambiense and Rhodesiense trans- 

 mitted to Man ? 



By two-winged blood-sucking flies of the Genus Glossina 

 (Tsetse flies). When the infected insect " bites,'* i.e., 

 pierces the skin with its proboscis, it introduces the try- 

 panosomes while sucking the blood. . 



T. gambiense is transmitted principally by Glossina 

 palpalis, and T. rhodesiense by Glossina morsitans. 



