Trypanosoma Evansi oy Horse Flies. 



165 



Trypanosoma Evansi, and which had itself been previously infected by 

 the bites of flies experimentally. On the seventh day the organisms 

 were found in the blood in small numbers, and steadily increased 

 during the next two days to swarming — that is, over fifty in the field 

 of a Zeiss D lens, and after oscillations the animal died on the tenth 

 day after the appearance of the organisms in the blood. Post-mortem 

 the usual lesions were found, the spleen being very much enlarged. 

 The right axillary glands were much enlarged, and contained the 

 organisms, while those of the left axilla were but half the size of those 



Chart of dog infected by the bites of horse flies which had just 

 previously bitten a surra dog. 



Or ganism s. 

 Swarming. 



Very 



numerous. 



Numerous. 



Few. 



Absent. 



Dotted Line = Temperature Curve. 



Continued Line = Curve of number of organisms 

 in the Hood. 



of the right side, which is of importance in connection with the fact 

 that the flies had been applied to the upper part of the right side of 

 the body within the area whose lymphatics pass to the right axillary 

 glands. The glands of the right groin were also larger than those of 

 the left, and also contained the organisms in large numbers. 



Unfortunately these experiments could not be extended to horses 

 on account of the necessary flies only being found at the height of the 

 Muktesar Laboratory (7 800 feet above sea level) during the three or 

 four hottest months, and they were not available in the rainy season 

 when a horse had been obtained for the experiment. The skin of this 

 animal, however, is so thin that it would be likely to be at least as 

 easily infected as a dog, while the facts above recorded will readily 



