48 TUB SOCIETY EOR TILE PRESERVATION OE 



hand, cattle (Bovidce) appear to bo without exception refractory to 

 inoculations with T. gambiense. 



' In Africa both nagana and sleeping sickness are transmitted 

 by the bites of certain species of tsetse-flies, the genus Glossina of 

 zoologists. Nagana is carried chiefly by the species Glossma 

 morsitans, G. pallidipes, and perhaps G.fusca and others; sleep- 

 ing sickness by G. palpalis. Hence these trypanosomiases have 

 been termed in a general way " tsotse-fly diseases." The tsetse- 

 fly is quite harmless in itself ; it is merely the carrier of the 

 infection : that is to say, if it has bitten an infected subject, it is 

 capable afterwards of 'inoculating a healthy subject with the 

 puncture of its proboscis. , 



'This, of course, raises the question as to whore the infection 

 comes from in the first instance, in the case of sleeping sickness 

 this question cannot at present be answered. It is highly probable 

 that there is some wild animal which harbours the parasite, and 

 from which the fly brings it to man ; but this " natural host " of 

 T. gambiense is at present hypothetical and has not been discovered. 

 The fact mentioned above, however, that Bovidce are immune to 

 inoculations with T. gambiense, makes it in the highest degree 

 improbable that the buffalo can be accused of any connection with 

 sleeping sickness. The general distribution of this disease 

 suggests that it has no connection with big game at all. In 

 Uganda it occurs only as a disease going from man toman; the 

 question of its origin must be studied, apparently, in regions 

 further west, perhaps on the Congo, where it is endemic. At 

 present, however, we can only make negative statements about its 

 origin, except where experimental evidence shows us that certain 

 animals are immune to it, evidence! which enables us to narrow 

 the field of inquiry, and to exclude, I think I may say, all Bomda, 

 and therefore also the buffalo. 



' The case of nagana, on the other hand, is quite different. 

 There exists definite evidence to show that Trypanosoma Brucn 

 occurs naturally in wild game and that the tsetse flies bring it 

 from game to domesticated animals. In the first place, try- 

 panosomes resembling '/'. Ilnwii, are to bo found in the blood oi 

 game. I have in my possession slides of the blood of wild 

 buffaloes showing such trypanosomes. In the second place, Bruce 

 was able to produce nagana in healthy domesticated animals by 

 inoculating them with the blood of freshly-killed wild animals. 

 The blood of eight buffaloes, injected each into a different dog, 

 infected one of the dogs; with 18 wildebeestes' blood, 8 dogs were 

 infected- with 4 koodoos' blood, 3 dogs were infected; and other- 

 infections were produced with the blood of a bush-buck and of a 

 hyena Hence there can be no doubt that the parasite of nagana 

 occurs naturally in wild animals, to which it appears to_ be 

 innocuous, though producing fatal results when inoculated into 

 domesticated animals. 



'To sum up: there is no evidence ol. any connection between 

 sleeping sickness and big game; the evidence that exists is all 



