Experiment 108. —Guinea-pig. From March 13 to 27, 1904, 194 larvae were 
fed. The blood was examined regularly until the end of May, and then at long 
intervals until September, 1905 (death from pneumonia) ; trypanosomes were never 
seen. 
III. TWELVE HOURS INTERVAL 
To infect a susceptible animal with Trypanosoma gambiense by 
the bites of larvae fed at least 12 hours* previously on an infected 
animal. 
Experiment 60.—Guinea-pig. From December 30, 1903, to April 27, 1904, 454 
larvae were fed. The blood was frequently examined until May, 1904, and then at 
intervals until October, 1905 (death from pneumonia) ; trypanosomes were never 
seen. 
II. EXPERIMENT WITH ANOPHELINES 
The mosquitoes used in this experiment were bred from larvae 
caught at Leopoldville; they were practically all Pyretophorus 
costalis. 
To infect a susceptible animal with Trypanosoma gambiense 
by the bites of anopheles fed on an infected animal at least 24 hours 
previously. 
Experiment 53.—Guinea-pig. From December 15, 1903, to May 8, 1904, about 
75 mosquitoes, fed from twelve to 72 hours previously on infected animals, 
fed on this guinea-pig. The blood was examined regularly without result until the 
animal was accidentally killed on August 8, 1904 ; no trypanosomes or signs of 
trypanosomiasis were seen at the autopsy. 
HI. EXPERIMENT WITH SIMULlUAl 
During the rainy season there were legions of Simulium about 
the sleeping sickness hospital at Leopoldville. It was hoped to do a 
series of experiments with them, but they were found to be so difficult 
to manage that the idea was given up. 
Some of these flies, freshly caught at the hospital, were, however, fed on a 
guinea-pig; five of them had in addition fed an hour previously on a heavily 
infected guinea-pig. The animal was kept under observation for 22 months ; it 
never became infected. 
IV. EXPERIMENTS WITH ORNJTHODOROS MOUBATA 
Because of the following observation, it was thought that this 
tick might disseminate sleeping sickness. 
At Nyangwe, out of four women presenting themselves as suffering from fever 
alter ih e bites of Ornilhodoros moubata, three were infected with trypanosomiasis. 
AH four women were wives of an arabised chief and inhabited a house, " 
Ornilhodoros moubata swarmed, in a well-kept village situated in open count J ’ 
tsetse-flies were consequently very rarely seen in the neighbourhood of their 
dwelling place. _ 
.I*te larvae were used several Umts and therefore some 
anS‘ entS I07a ’ 168 and 60 had P° ssibl y fed seVCral UmeS 
of those employed in 
previously on infected 
