228 



The Philippine Journal of Science 



191S 



ments, but has never been seen in flies attacking animals in the 

 natural state. 



Considering that there might be a remote possibility of con- 

 veyance of infection through this peculiarity in feeding habits, 

 five experiments, based on this hypothesis, were attempted. 

 The technique was the same in all of the 5 guinea pigs used. 

 A highly infected guinea pig was used to contaminate the 

 flies. A portion of the skin of infected and healthy animals 

 was abraded with a razor and the flies applied individually in 

 tubes. The fly was permitted to lap the blood from the abrasion 

 on the infected animal for a minute or less and then transferred 

 immediately to the healthy animal, where it was induced to 

 apply its labellum for from five to ten minutes. 



Table III. — Attempts to transfer infection by the fly's labellum. 



negative.^ 



Results 



Date. 



No. of 



guinea 



pig. 



Flies 

 applied. 



Nov. 21 



85 

 91 

 110 

 104 

 123 



3 

 2 

 2 

 4 

 3 



Nov. 22 



Do 



Nov. 23 - 



Nov. 24 





* The experiment of gruinea pig 110 was checked by subsequent inoculation to which the 

 animal became infected. 



The results of all the trials were negative, although it was 

 ascertained that typical trypanosomes were present upon the 

 labellum of one of the flies and in the stomach of another fly 

 immediately after the experiment. 



These experiments were supplemented by an experiment at- 

 tempting to transfer infection to abrasions by the pulvilli of 

 the contaminated fly. This also resulted negatively. 



LENGTH OF TIME TABANUS STRIATUS HARBORS TRYPANOSOMES 



An attempt was made in this series of experiments to deter- 

 mine the maximum length of time surra organisms remain 

 alive in the gut of the fly. The fly was fed in each instance on 

 a guinea pig showing numerous trypanosomes in its blood. As 

 noted in Table IV trypanosomes indistinguishable from surra 

 organisms were found in suspensions from flies up to thirty 

 hours after biting a sick animal. Beyond ten hours, inoculations 

 of infected flies into susceptible animals were negative. 



