EXPERIMENTS WITH TSETSE. 273 



" The Tsetse differs from the mosquito in that both sexes are 

 blood-sucking flies. 



" It is said that the fly follows the large game, but I never 

 found them in any number in places in which a few minutes 

 before large herds of buffalo or wildebeeste had been standing. 

 Of course, the fly may have literally followed the game. One 

 day, after killing a wildebeeste, I certainly found a largo number 

 of Tsetse on the dead animal, and again on a dead butialo I 

 counted as manv as forty flies feeding on it at the same time " 

 (p. 3). 



Exjjeriments toitJi the Tsetse-fly (pp. 4-16). — These experiments 

 are divided into seven series, and were made with a view to the 

 elucidation of the following questions : — ■ 



" (a.) Is the Tsetse-fly capable of giving rise per se to any 

 local or general disease in susceptible animals ? 



" (6.) Can the Tsetse-fly convey the disease from an affected 

 animal to a healthy one? 



" (c.) How long does the Tsetse-fly retain this infective power ? 



"(<^.) How long does the blood of an aflected animal remain 

 capable of giving rise to the disease in a dried condition ? 



" (e.) How long does the blood of an aflected animal remain 

 capable of giving rise to the disease if kept in a natural con- 

 dition 1 



" (/.) Does the Tsetse-fly under natural conditions convey the 

 disease from animal to animal 1 



" (g.) Is the Tsetse-fly capable of giving rise to the disease if 

 taken out of the Fly Country into a healthy locality ? " 



(n.) Details are given of three experiments in which various 

 numbers of Tsetse-flies, brought from the Fly Country and then 

 Icept in captivity at Ubombo for some days, in order to give time 

 for the hwmatozoon to disappear, in case it had been present 

 in the bodies of the flies when they were caught, were sub- 

 sequently fed daily on dogs during periods varying from ten days 

 to two months. All the dogs remained perfectly healthy, and 

 continued so after the experiments were stopped. The author 

 adds : " The above experiments then prove, I trust satisfactorily, 

 that the Tsetse-fly is not capable of giving rise per se to any local 

 or general disease in susceptible animals " (p. 4). 



(6.) In connection with the question : " Can the Tsetse-fly 

 convey the disease from an affected to a healthy animal ? '"' the 

 author writes as follows (p. 5) : — 



" That all blood-sucking flies are not capable of transferring 

 the Fly Disease from affected to healthy animals is, I think, 



T 



