ROLE OF STOMOXYS CALCITRANS. 



493 



Table VIII. — Representing successive interrupted feeding from infected to 



healthy guinea pigs. 



Date. 



Infected 

 animal 

 used. 



Condition of blood 

 of donor relative 

 to trypanosomes. 



No. of 



healthy 



guinea 



pigused. 



Num- 

 ber of 

 flies 

 ap- 

 plied. 



Length 



of time 



fed on 



surra 



host 



(average 



per fly). 



Interval 

 between 

 feedings 

 (average 

 per fly). 



Time re- 

 quired to 

 complete 

 meal on 

 healthy 



host 

 (average 

 per fly). 



Duration 

 of experi- 

 ment. 



June 20 

 June 21 

 June 22 

 June 23 

 June 24 

 June 25 

 June 26 

 June 27 

 June 28 

 June 29 

 June 30 

 July 1 

 July 2 

 July 3 

 July 4 

 July 5 

 June 30 

 July 1 

 July 2 

 July 3 

 July 4 

 July 5 



127 

 127 

 127 

 127 

 127 

 127 

 127 

 127 

 C 



c 

 c 

 c 

 c 

 c 

 c 

 c 



A 

 A 

 A 

 A 

 A 

 A 



Swarming 



Numerous 



Swarming 



do 



177 

 177 

 177 

 177 

 177 

 177 

 177 

 177 

 187 

 187 

 187 

 187 

 187 

 187 

 187 

 187 

 129 

 129 

 129 

 129 

 129 

 129 



6 



5 



6 



5 



5 



4 



6 



5 



4 



4 



4 



4 



3 



8 



3 



3 



31 



28 



25 



20 



42 



60 



Seconds. 

 35 

 30 

 20 

 20 

 25 

 25 

 25 

 20 

 20 

 20 

 20 

 20 

 25 

 20 

 25 

 20 

 15 

 15 

 20 

 20 

 20 

 20 



Seconds. 

 36 

 60 

 60 

 10 

 30 

 5 

 15 

 30 

 10 

 50 

 40 

 20 

 25 

 20 

 30 

 35 

 50 

 25 

 35 

 30 

 25 

 30 



Mi. sees. 



3 30 



4 00 



2 00 



3 00 

 3 30 

 2 30 



2 00 



3 00 

 2 30 

 2 00 

 2 00 

 2 00 

 2 00 



2 00 



3 00 

 3 00 

 3 00 

 3 00 



1 30 



2 00 



3 00 

 1 30 



Hr. mine. 



1 00 



1 00 



80 



86 



20 



40 



80 



26 



20 



26 



15 



20 



25 



16 



16 



10 



6 00 



6 00 



3 00 



1 00 



8 00 



8 00 



do 



Numerous 



Swarming 



do 



Numerous 



Scanty 



Moderate 



-... do . . . 



Numerous 



Swarming 



do-.._ 



Numerous 



Scanty ... 



Moderate 



Numerous 



Moderate 



do 





The guinea pigs employed in the first two experiments were 

 negative up to August 1, 1912, when they were inoculated 

 with blood of a guinea pig positive for surra. Both reacted in 

 the usual manner, showing numerous trypanosomes on the fifth 

 and sixth days, respectively. Both were alive and positive for 

 surra up to August 26, 1912. 



A positive result was obtained in the third experiment with 

 guinea pig 129 which showed scanty trypanosomes on July 11, 

 six days after the last lot of flies was applied to it. On the 

 following day trypanosomes were present in moderate numbers, 

 and two guinea pigs were inoculated with its blood. These 

 showed trypanosomes on the seventh and eighth days after inocu- 

 lation. Guinea pig 129 was examined daily until August 11, 1912, 

 during which time trypanosomes were seen in numbers from 



