384 Col. Sir D. Bruce and others. [Apr. 18, 



r. The Development 0/ Trypanosoma vivax in Laboratory-Bred Glossina palpalis. 

 Table IX. — Development of Trypanosoma vivax in Laboratory-Bred 



Glossina palpalis. 



Experiment. 



No. of flies. 



No. of 



days fed on. 



No. of days before 

 flies became infective. 



No. of days flies 

 remained infective. 



1591 



50 



4 



21 



21 



1638 



25 



6 







1698 



68 



4 



35 



35 



1700 



60 



4 



30 



30 



1870 



50 



? 







rive experiments were made with laboratory-bred flies. Three were 

 successful. 



Experiment 1591. 



Date. 



Day 

 of experi- 

 ment. 



Procedure. 



Result. 



Remarks. 



Positiye. 



Negative. 



1909. 

 Sept. 2—4 



„ 5—6 



„ 8-9 

 „ 10—30 



Oct. 1—3 



1—2 



3—4 



5 



6-7 

 8—28 



29—31 



Plies fed on infected 



calf, 1318 

 Flies starved. 

 Flies fed on infected 



calf, 1318. 

 Flies starved. 

 Flies fed on healthy 



goat, 1652 

 Flies starved. 



+ 





50 flies used. 



Oct. 4, 35 remaining 

 flies dissected; nega- 

 tive except 3, which 

 had infected pro- 

 bosces. 



Remarks. — Fifty laboratory-bred flies were fed for four days on an infected calf ; 

 21 days after their fiist feed they became infective ; 35 flies remained alive on the 

 32nd day. On these being dissected three were found with infected probosces. These 

 probosces were not injected into animals, so that it is not known if the flagellates were 

 infective by injection. 



Experiment 1G38. 



Date. 



Day 

 of experi- 

 ment. 



Procedure. 



Besult. 



Rciuiirks. 



Positive. 



Negative. 



1909. 

 Sept. 6—11 



„ 12—13 

 „ 14—29 



1—5 



6-7 

 8—23 



Flies fed on infected 



calf 

 Flics sdarvcd. 

 Fli<'s fed on licaltliy 



goat, 1082 







25 flics used. 



Sept. 29, 23 remain- 

 ing ilicH accidentally 

 killed ; negative on 

 dissection. 



Itcmarks. — Twenty-five laboratory-bred flics were fed for six days on a calf infected 

 witli Tn/panosowa vivax, and afterwards for 16 days on a healthy goat. Tiiis goat was 

 .not infected, and tlie remaining 23 flics when killed and dissected all proved negative. 



