26 



Dr. H. L. Duke. Experiments with [Sept. 28, 



Monkey 426 became infected on November 27. On December 4, when 

 trypanosornes were showing -f + + + , it received - l grm. arsenphenylglycin 

 per kilogramme. Trypanosornes disappeared the following day and were 

 not seen again, although the monkey was examined daily until death on 

 J anuary 9. 



Expt. 417. 



Date. 



Day of 

 expt. 



Procedure. 



Eemarks. 



Sept. 30— Oct. 1... 



Oct. 2 



„ 3 



„ 26— Nov. 9 



Nov. 10—21 



„ 22— 24 



1 

 2 

 3 



4—25 

 26—40 



41—52 

 53 — 55 



Fed on Monkey 199 (T. gambiense + ). 

 Fed on cock. 

 Starved. 

 Fed on cock. 



Fed on cock. 



Monkey 494 becomes 

 infected. 



3 + flies out of 103 dis- 

 sected = 2 8 per cent. 



It is possible that the + fly in Experiment 416 did not feed upon 

 Monkey 426 on the first day after the arsenic feeding. The strength of the 

 drug to which the newly-imbibed trypanosornes were subjected would thus 

 be reduced. In any case, the trypanosornes in Monkey 426 at the end of the 

 experiment showed no resistance to arsenic. 



Experiments 428 and 429, in each of which 89 flies were employed, and 

 Experiments 350 and 351, in which 121 and 77 flies were used respectively, 

 were useless, as no flagellates were found in either the arsenic boxes or their 

 control. 



Expt. 714. 



Date. 



Day of 

 expt. 



Procedure. 



Eemarks. 



Apr. 17—18 



„ 19 



„ 20— May 20 

 May 21 



1 

 2 



3—33 

 34 



Fed on Monkey 597 (T. gambiense + ). 



Starved. 



Fed on cock. 



Dissected 



7 + flies found out of 

 61 dissected = 11'4 

 per cent. 



