1912.] Antelope and their Relation to Trypanosomiasis. 157 



frequently examined, they have never shown any sign of Sleeping Sickness 

 either clinically or upon blood examination. 



As all the mainland flies in the following experiments were caught upon 

 a short stretch of shore to the west of the mouth of Buka Bay, which is 

 visited several times weekly, it is extremely improbable that stray natives 

 alone could account for the prolonged infection. The suspicion that either 

 the antelope or reptiles which frequent the lake shore are acting as a reservoir 

 for T. gamhiensc becomes increasingly probable the longer the wild flies remain 

 infective. As to whether reptiles can serve as a reservoir, the difficulty of 

 obtaining live crocodiles or water-lizards has, up to the present, prevented 

 any satisfactory investigations being carried out on this point. That the buck 

 are important in this connection was foreshadowed by results obtained in the 

 laboratory experiments with these animals, some of which have proved 

 capable of infecting laboratory-bred Glossina palpa/is more than twelve 

 months after their original infection with T. gambiense. If an infected buck 

 took up its quarters in the forest behind the fly ground, it might account for 

 the recent outburst of infectivity among the fly after a long period of relative 

 quiescence. From prolonged observation, it would appear that bushbuck, at 

 any rate, among the antelope frequenting the lake shore are very limited in 

 their feeding range. 



The objection that these animals would not, by virtue of their nocturnal 

 habits, be exposed to the bites of the fly, may be dismissed at once. On 

 several occasions I have seen bushbuck feeding at the water's edge as late as 

 8.30 A.M., long before which time the sun is powerful and the fly actively 

 aggressive. Upon one occasion a herd of waterbuck was seen actually in the 

 water at 11 A.M., in the full glare of the sun. Situtunga also, as will be seen 

 later, are by no means so exempt from the attentions of the fly as the general 

 impression of their habits would suggest. 



Against the objection that the thick hair of an antelope would prevent a 

 fly from piercing the skin over the greater part of the body, I may say that 

 I have observed Stomoxys in numbers vigorously sucking blood on the 

 haunches and sides of the body of a newly-killed bushbuck, regions where 

 the hair is exceedingly thick. 



As regards the possibility of the longevity of the fly affording a solution of 

 the problem, I am unaware of any evidence of G. palpalis surviving for more 

 than 227 days — an observation recorded by Dr. Kleine. With a view, then, 

 to completing the chain of evidence incriminating the lake-shore antelope, the 

 experiments given below were undertaken. Owing to the nature of the 

 country, the expectations of a positive result from the mainland were 

 extremely poor, as the places where buck can be shot are not necessarily 



