1912.] 



Arsenphenylglycin and T. gambiense in G. palpalis. 23 



Fly 2. Gut (empty forward with a little pale fluid posteriorly) : Some 

 tendency towards posterior swelling, but still active. 

 Salivary glands : + + + , active and normal. 

 Fly 3. Gut (containing altered blood) : + + + , active, but some show 

 posterior swelling. 

 Salivary gland : + + , apparently normal. 

 Fly 4. Gxd (containing altered blood) : + + + , few dead, many altered in 

 shape but still slowly motile, others active. 



The flagellates of these flies show less effect from the arsenic than is usual 

 at this period. 



It may be remarked, as justifying the conclusion that the above departures 

 from the normal in the flagellates are due to the action of the drug, that such 

 alteration in form and motility have never before been seen in positive flies. 



The dead flies are removed every morning, and in the normal course of 

 events the flagellates are always seen to be actively motile with no such 

 morphological changes as those described above. Moreover, in cases in which 

 the normal flies have been left until the flagellates are moribund, death occurs 

 without the characteristic swelling of the posterior part always to be observed 

 in the presence of arsenic. 



Expt. 550. — Positive Box of G. palpalis. 



Date. 



Procedure. 



Remarks. 



Jan. 31— Feb. 1 ... 



Feb. 2 



„ 3 



Fed on Monkey 632 48— 72 hours after 

 administration of arsenphenylglycin, 

 - 1 grm. per kilogramme. 



Starved. 



+ Flies 1 and 2 found. 







Description of the two positive flies : — 



Fly 1. Gut : + + + , normal (no traces of blood seen). 



Salivary glands : + + + , normal. 

 Fly 2. Gut : + + , a few are altered as described above. 



Salivary gland : + + + , normal. 



A very slight effect appears to have been exerted in Fly No. 2 by the 

 arsenic. Fly No. 1 either fed very slightly or not at all on Monkey 632. 



