20 



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



varying periods after the feeds upon the arsenic monkey. I have here to 

 express my indebtedness to her for the description of the flagellates found. 

 It was constantly noticed in the ease of flies which had fed upon a recently 

 inoculated monkey that the walls of the intestine were unduly brittle and 

 friable, and clean dissection very difficult. This was to a great extent 

 avoided by starving such flies for several days after the ingestion of the 

 arsenic blood before dissecting them. In the following experiments various 

 changes were noted in the flagellates in the fly, due presumably to the action 

 of the drug in the blood imbibed : — 



Expt. 29. — Positive Box of G. palpalis. 



Date. 



Procedure. 



Remarks. 



Oct. 1—2 

 „ 3 



Fed on Monkey 418 24 — 48 hours after 

 administration of - 1 grm. arsenphenyl- 

 glycin per kilogramme. 



1 fly dies ; nil. 



Monkey 502 becomes infected. 



2 flies die ; nil. 

 Monkey 427 becomes infected. 



1 fly dies ; nil. 

 1 + fly found. 



„ 4 



5 



„ 6 



Fed on clean Monkey 427 



Description of the positive fly : — 



Gut : Shows flagellates very much modified, with swollen posterior end ; 

 many dead. 



JProventriculus and thoracic gut : N o flagellates seen. 



Salivary glands : Normal, though somewhat slight infection. 



It will be noted that for two consecutive days after feeding on the arsenic 

 monkey this fly was infective to monkeys. The condition in this fly affords 

 strong confirmation of the theory that the salivary gland flagellates are the true 

 infecting form. 



Expt. 74. — Positive Box of G. palpalis. 



Date. 



Procedure. 



Remarks. 



Oct. 24—25 

 „ 26 



Fed upon Monkey 488 24 — 48 hours after 

 the administration of arsenphenylglycin, 

 - 1 grm. per kilogramme. 



9 flies die, among which is 

 + Fly No. 1. 



2 flies die, one negative, the 

 other + Fly No. 2. 



Monkey 503 became infected. 



1 fly dies ; nil. 

 + Fly No. 3 found. 



„ 27 



„ 28 



Fed on cock. 



„ 29— Nov. 1... 

 Nov. 2—4 



„ 5-6 



Fed on cock. 



