1912.] Arsenphenylglycin and T. gambiense in G. palpalis. 21 

 Description of the three positive flies : — 



Fly 1. Gut : Few altered flagellates, all dead, with swollen posterior ends, 

 and generally altered. 

 Proventriculus : Nil. 



Salivary glands : Only one gland obtained ; this contained living 

 and apparently quite normal flagellates. 

 Fly 2. Gut and Proventriculus : Show no flagellates, living or dead. 



Salivary glands : Contained flagellates + + + , actively motile. 

 Fly 3. Gut : + + + , apparently normal. 



Prove ntriml us : Nil. 



Salivary glands : + + 4- , normal. 



Whether the condition of this fly is due to the original gut flagellates 

 having escaped destruction by the arsenic, or whether in the 10 days which 

 elapsed between the arsenic feeds and dissection the gut became reinfected 

 from the salivary glands, cannot be decided. In relation to the first 

 alternative it is improbable that a fly would refuse to feed upon two 

 successive days unless at the point of death. 



The mortality after the arsenic feeds should be noted in this and other 

 similar experiments. 



Expt. 357. — Positive Box of G. -palpalis. 



Date. 



Procedure. 



Remarks. 



Oct. 10—11 ... 



„ 12 



Fed on Monkey 452 24 — 48 hours after administra- 

 tion of arsenphenylglycin O'l grm. per kilogramme. 



7 flies die ; nil. 

 1 + fly found. 



„ 13 









(This box was killed by wood-smoke instead of the usual chloroform.) 

 Description of the positive fly : — 



Gut: Flagellates all dead, shape considerably altered, the posterior end 



being frequently swollen up to a marked degree. 

 Salivary gland : Numerous flagellates, but all dead ; shape perfectly normal. 



Apparently this curious condition of the gland flagellates was due to the 

 smoke. The effect of this treatment is very marked ; the glands show a 

 dark granular appearance very different from the clear transparent state 

 to be observed in normal specimens. This darkening of the glands proved 

 by subsequent experiments to be a characteristic of smoke-killed flies. 

 This condition has never been observed in flies killed with chloroform. 



Note the mortality after the arsenic feeds. 



