1912.] Arsenphenylglycin and T. gambiense in G. palpalis. 27 



Expt. 715 (control). 



Date. 



Day of 

 expt. 



Procedure. 



Remarks. 



Apr. 17—18 , 



n 19 



20—25 

 „ 26—27 



„ 28 



„ 29 



„ 30— May 20 

 May 21 



1 



2 

 3—8 

 9—10 



11 

 12 

 13—33 

 34 



Fed on Monkey 597 (T. gambiense + ). 



Starved. 



Fed on cock. 



Starved. 



Fed on Monkey 724. 

 Fed on cock. 



Monkey 724 received 

 O'Oo grrn. per kilo- 

 gramme arsenphenyl- 

 glycin on April 25. 



1 + fly found out of 58 

 dissected = 1*8 per 

 cent. 







This positive fly showed only a slight gut infection ; no flagellates were 

 present in salivary glands or proventriculus. This is an extremely backward 

 state of development for the age of the fly. 



From these experiments it appears that ingestion of arsenic blood 

 immediately after the infecting feeds checks subsequent development of 

 flagellates in the fly. 



IV. To Investigate the Prophylactic Properties of Arsenphenylglycin against the 

 Bite of G. palpalis Infected with T. gambiense. 



In a paper summarised in the ' Sleeping Sickness Bulletin,' No. 24, vol. 13, 

 Mesnil and Kerandel give some experiments dealing with the proph} T lactic 

 action of arsenphenylglycin against inoculation of T. gambiense into monkeys. 

 The following experiments were undertaken on similar lines, but only the 

 smaller doses used by the French observers were employed. Thus in the 

 first series 0*1 grm. of the drug per kilogramme was inoculated sub- 

 cutaneously ; in the second - 05 grm. per kilogramme. Such proportions 

 when applied to man involve a relatively enormous dose of the arsenphenyl- 

 glycin. Nevertheless, although the practical application of the results given 

 below may be very limited, the much greater potency of the drug against 

 the fly infection is of considerable interest. 



In undertaking such experiments with living flies an obvious difficulty 

 arises in the uncertainty as to whether the infected fly has fed upon the 

 experimental animal. To insure this as far as possible without at the same 

 time vitiating the exactness of the experiment, each box of flies was placed 

 upon the monkey for two consecutive days, and on each day repeated efforts 

 •were made if the flies showed reluctance to feed. In the great majority of 



