1912.] Trypanosoma gambiense from Tragelaphus spekei. 485 



noted that in the case of all the strains employed the trypanosomes had more 

 or less recently passed through Glossina palpalis. This is also presumably the 

 case with the Damba strain as found originally in the wild antelope. This 

 fact is of considerable importance in that it eliminates all idiosyncrasies 

 acquired during continued maintenance in laboratory animals. 



Origin of trypanosome strain. Duration 



G-uinea-pig 690 ... 



Kihanga flies direct 



Namusenyu flies direct | 



Human strain from Monkey 199 through laboratory-bred | 

 O. palpalis 



Monkey 597 by inoculation 



„ 563 „ 



„ 113 „ 



Unman strain from laboratory antelope 



Monkey 199 through laboratory-bred G. palpalis j 



The average duration of the disease in rats (three experiments) is 61 days : 

 in four guinea-pigs 68 days: in seven monkeys 119 days. 



From a comparison of the above two tables it will be seen that there is a 

 close similarity in the animal reactions of all the trypanosomes employed. 

 In no instance does the disease in rats approach the virulence assumed by 

 T. brucei. There is, therefore, no reason to doubt that the trypanosomes 

 recovered from wild Lake-shore flies and from the wild situtunga are indeed 

 T. gambiense. 



A visit was paid to Sese Islands where Carpenter had recently obtained an 

 infection in a monkey with some 6000 odd flies. G. palpalis were found to 

 be very numerous and many situtunga tracks were seen. The natural 

 conditions on the islands visited are, however, apparently very much less 

 favourable to the perpetuation of sleeping sickness by these animals than is 

 the case with Damba. There are tracts of open country, between and 

 behind the forests which fringe most of the Lake shore, where situtunga come 

 out to feed and where there are no tsetse. The antelope do not, therefore, 

 enter a fly area immediately upon leaving the shelter of the forest and 

 papyrus as is nearly always the case on Damba. 



Six situtunga were shot during the trip. Their blood was examined in the 

 fresh state, by stained films, and by inoculation into goats and monkeys. By 



VOL. LXXXV. — B. 2 M 



