1910.] Reservoir of the Virus of Sleeping Sickness. 48 3 



Experiment 1451. 



Ninety laboratory-bred Glossina palpalis were fed for 10 successive days on a calf whose 

 blood contained Trypanosoma gamhiense. Tlie flies were starved for 72 hours. They 

 were then fed on a clean monkey daily for 45 successive days. The monkey failed to 

 develop Sleeping Sickness. 



When the remainder of the flies were dissected, one contained flagellates, but when the 

 contents of this fly were injected into a goat the animal failed to show any infection of 

 Trypanomrm gamhiense. 



Result. — Negative. 



Experiment 1269. 



The details of this experiment were similar to those of the last. After the Glossina 

 palpalis had been fed on two oxen whose blood contained Trypanosoma gambiense, they 

 were applied daily to a monkey. They were fed on this monkey for 35 consecutive 

 days and were then transferred to a second monkey. Both the monkeys remained 

 healthy. 



Two of the flies were found on dissection to contain flagellates, but when these were 

 injected into a monkey and a goat no development of Sleeping Sickness took place in 

 these animals. 



Result. — Negative. 



Experiment 1672. 



Here again the technique was similar to the last. The Olossina palpalis were fed, orp 

 alternate days for a lengthened period, on a clean monkey and a clean goat. Both, 

 animals remained healthy. 



Some infected flies were found on dissection, but when introduced under the skin of a. 

 goat and of a monkey did not give rise to Sleeping Sickness. 



Result. — Negative. 



The next two experiments, which were carried out in the same way as the 

 two preceding ones, were positive. 



Experiment 1566. 



The Glossina palpalis were fed on an infected ox, and after a starve of 72 hours were 

 fed on a clean monkey for 45 successive days. 68 days after the flies had taken their first 

 infected feed, this monkey developed Sleeping Sickness. 



When the fliies came to be dissected, nine of them showed flagellates either in the 

 proboscis or in the alimentary tract. Some of these were injected into goats and into a 

 monkey, but with negative results. 



Result. — Positive. 



Experiment 1602. 



Fifty laboratory-bred flies were fed for four successive days on an ox whose blood" 

 contained T rypanosoma gambiense. After a period of starvation they were applied to a 

 monkey and to a goat on alternate days. The monkey died before it could have become 

 infected, but the goat developed Sleeping Sickness 20 days after the flies had their fii-st 

 infected feed. 



The remainder of the flies, 32 in all, were dissected, and five were found to contain. 

 VOL. LXXXII. — B. 2 P 



