380 



Col. Sir D. Bruce and others. [^pr. 18, 



Only one experiment out of four'was successful. The flies became infective 

 21 days after their first feed on the infected dog. 



Experiment 574. 



Date. 



Day 

 of experi- 

 ment. 



Procedure. 



Result. 



Remarks. 





Positive. 



Negative. 



1909. 













Mar. 4—6 



1—2 



Flies fed on infected 

 dog 







500 flies iised. 



7—25 



3—21 



Flies fed on a fowl. 









„ 26—30 



22—26 



Flies fed on healthy 

 monkey, 649 



+ 





Mar. 25, 120 flies 



„ 31— 



27—30 



Flies fed on healthy 







alive, 



Apr. 3 





monkey, 650 







Apr. 14, 60 flies 



Apr. 4—8 



31—35 



Flies fed on healthy 







alive. 





monkey, 660 







May 3, 30 flies 



9—13 



36—40 



Flies fed on healthy 

 monkey, 678 







alive. 

 May 14, 22 remain- 



„ 14- 



41—70 



Flies fed on healthy 







ing flies dissected ; 



May 13 





monkey, 723 







all negative. 



Remarlcs. — Five hundred wild flies were fed for three days on a dog whose blood 

 contained numerous Trypanosoma dimm-phon. Twenty-one days after their first feed they 

 became infective. By the 27th day they lost the infection and did not regain it, 

 although kejit under observation for 71 days. None of the flies which died or were 

 killed and dissected showed any flagellates. It appears as if the infected fly had died 

 early in the experiment and had escaped notice. 



D. The Develop7nent of Trypanosoma dimorphon in Lahoratory-Brcd Glossina 



palpalis. 



Table VI. — Development of Trypanosoma dimorphon. in Laboratory-Bred 



Glossina palpalis. 



Experiment. 



No. of flies. 



No. of 

 days fed on. 



No. of days before 

 llii's became infective. 



No. of days flies 

 remained infective. 



1642 



50 



4 



14 



14 



1675 



50 



3 







1676 



50 



3 







1843 



140 



4 







Four experiments were carried out, as in the Lake-shore group, and ono 

 also was successful. 'J'Ih; flies became infective on or about the 14tli day. 



