154 DR. J. KIEK ON THE TSETSE FLT OF TROPICAL AFRICA. 



All affirm that on entering certain localities by day the oxen die 

 shortly afterwards : this they have proved, not in the small num- 

 bers of twenty or forty noticed by Europeans, but in herds con- 

 sisting of hundreds ; whether in great or small numbers they have 

 found the result alike. They have further learned that these 

 deadly places may be crossed with safety by night if sufficiently 

 narrow to allow of the cattle being driven through before sunrise. 

 This has been tested by Europeans and found also correct ; 

 further, that goats remain vinaffected ; and sheep suffer in a less 

 degree than oxen. 



From observing a fly constantly present in these deadly parts, 

 the natives have drawn the natural inference that it is the cause 

 of the loss : nor indeed can I suggest a better theory ; the fly is 

 the only thing constant in all such parts, and absent from others 

 with which we are acquainted. The fact that the sucking calf 

 lives, while the mother dies, at once suggests the idea of some 

 poisonous herb ; Major Vardon's experiment, however, makes us 

 doubt this ; and the dog and cow both die, whose food is so unlike. 



On the other hand, we find the confines of the fly and the dis- 

 ease exactly correspond ; also when the fly is dormant no mischief 

 ensues. The fly avoids human excrement, so the natives told us, 

 and we have found it true, and they say that cattle have been 

 passed by day through fly country when smeared with a compo- 

 sition containing this. Native doctors have an herb to which 

 they attribute a similar eflect, but even they never assert that it 

 will save all ; only a small per cent, of the cattle exposed is the 

 most they claim. 



It has been suggested that lung-sickness, African distemper, or 

 some such disease is the cause of death. Is it likely that a num- 

 ber of intelligent men, all of whom had previously been acquainted 

 with these diseases, should have failed to recognize them again ? 

 Besides, they differ manifestly from the " Tsetse " disease in being 

 contagious and spreading from one place to another and from 

 one animal to another, whereas only those bitten by the fly die ; 

 and no danger has been apprehended, or experienced, by such 

 cattle mixing with others. 



As to what that disease is I can say almost nothing. I have 

 seen the animals become languid, lose flesh, droop the ears, swell 

 at the eyes, which gave a discharge, tlie coat began to stave : as to 

 the bites, they simply showed the smallest swelling, and a little 

 moisture on the hair around. On dissection (the animals being 

 killed when these first symptoms appeared) the flesh had in some 



