1910.] The Development of Irypanosomes in Tsetse Flies. 377 



Experiment 1651. 



Date. 



Day _ 

 of experi- i 

 meut. 



Procedure. 



Eesult. 



Eemarks. 



Positive. 



Negative. 



i 



1909. 

 Sept. 11—14 ; 



„ 15—16 

 „ 17—24 



„ 25— 

 Oct. 29 

 Oct. 30—31 



1—3 



4—5 

 6—13 



14—48 



49—50 



Flies fed on infected 



monkey 

 Flies starved. 

 Flies fed on healthy 



monkey, 1651 

 Flies fed on healthy 



monkey, 1720 

 Flies starved. 



+ 





60 flies used. 



Monkey 1651 died 

 on 13th day. 



Nov. 1, 32 remaining 

 flies killed and dis- 

 sected ; 4 found in- 

 fected. 



Remarks. — Sixty laboratory-bred flies were fed daily for four days on an infected 

 monkey. Forty-one dnys after their tirst infected feed they became infective. Four 

 flies infected with flagellates were found among the 32 which remained alive on the 

 51st day. They were not injected into animals. 



Experiment 1712. 



Date. 



Day 

 of experi- 

 ment. 



Procedure. 



Eesult. 



Eemarks. 



Positive, j Negative. 



1909. 

 Sept. 23— 



Oct. 5 

 Oct. 6—7 

 „ 8- 

 Nov. 2 

 Nov. 3 



1—12 



13—14 

 15-40 



41 



Flies fed on infected 



monkey 

 Files starved. 

 Flies fed on healthy 



monkey, 1790 

 Flies starved. 







50 flies used. 



Nov. 4, 31 remaining 

 flies killed and dis- 

 sected ; 1 found in- 

 fected. 



Remarks. — Fifty laboratory-bred flies were fed daily for 13 days on an infected monkey. 

 The flies became infective 32 days after their first feed. On dissection of the remaining 

 31 flies on the 41st day, one was found to be infected with flagellates, but it did not give 

 rise to the disease when injected into a healthy monkey. 



Experiment 1760. 



Date. 



Daf 

 of experi- 

 ment. 



Procedure. 



Ees\ilt. 



Eemarks. 



Positive. 



Negative. 



1909. 

 Oct. 1—5 



. 6-7 

 „ 8- 

 Nov. 6 

 Nov. 7 



1 - 



1 



I 



1—4 



5—6 

 7—36 



37 



Flies fed on infected 

 1 monkey 



Flies starved. 

 1 Flies fed on healthy 

 1 monkey, 1760 

 \ Fhes starved. 



+ 





60 flies used. 



Nov. 4, 1 infected fly 

 injected into healthy 

 monkey. 



Nov. 8, 28 remaining 

 flies killed and dis- 

 sected ; all negative. 



