SCEPTICISM AS TO POWEES OF TSETSE. 35 



that he failed to find any such structure, since the salivary 

 glands, the secretion from which produces the irritation which 

 is experienced after a stab from a biting fly, are always situated 

 in the thorax. 



Sir Samiiel Baker [29], writing in 1866, mentioned the 

 Tsetse-fly as occurring in Obbo, to the south-east of Gondokoro, 

 a new locality. James Chapman, in his " Travels in the Interior 

 of South Africa" [30], published in 1868, gave copious details of 

 the occurrence, habits, and effects of the Tsetse in the country 

 to the south of the Zambesi, mentioning among other things an 

 instance of acquired immunity to Tsetse-fly disease in the case of 

 Makoha dogs, which " from time immemorial " have been bred 

 by natives in the Fly country. 



An early letter from Karl Mauch [36], the German pioneer- 

 explorer of the gold-fields of the northern Transvaal and 

 Mashuna Land, and subsequent discoverer of the ruins of 

 Zinibabye, published in 1869, is interesting from the fact that 

 it mentions an external application of Asafoetida, or internal 

 application of ammonia as possible remedies for Tsetse bite. 

 In the same year Mr. and Mrs. Petherick [37] encountei-ed 

 the Tsetse in the country of the Rhol Tribe, north-west of 

 Gondokoro. 



We now meet with the earliest expression of a certain 

 scepticism as to the reputed effects of the bite of the Tsetse 

 upon domestic animals, which, appearing first in the year 1870, 

 cfjutinued side by side with the orthodox belief until well into 

 the 'eighties. Mr. St. Vincent Erskine [38], an African traveller 

 well known at the time, addressing a meeting of the Natural 

 History Association of Natal on May 30, 1870, is reported to 

 have "combated the popular idea that the bite of the Tsetse-fly 

 was destructive to the life of certain animals, especially the ox, 

 horse, and dog." Mr. Erskine's theory " was that the deaths of 

 the animals were to be attributed more to change of grass or 

 climate than to the bite of such a small fly as the Tsetse." No 

 arguments are recorded in support of this belief, which is 

 evidently due to a revolt against the popular idea already 

 referred to, that the deaths of domestic animals bitten by the 

 Tsetse were caused by a poison secreted by the fly itself. The 

 belief in the existence of a specific Tsetse poison may be said to 

 have prevailed until the publication of the results o£ Col. David 

 Bruce's investigations in 1897 (see Chapter VII., Appendix A), 

 tliough, as we shall shortly see, the true state of the case was 



D 2 



