BELIEF m NOXIOUS FLIES IN AFRICA. 303 



able once more to call attention to the fact that, while a disease 

 that appears to be Nagana undoubtedly exists in Somaliland 

 (on the Webi Shebeli, in the Korayo Valley, the Aulihan 

 country and elsewhere),* with fatal effects to horses, camels, 

 donkeys, and mules, all the Tsetse- flies yet received from that 

 country prove to belong to Glossina longipennis, Corti. On the 

 other hand, the experience of Mr. W. A. Eckersley [134] near 

 Beira, in 1893,f lends force to the second of the above quoted 

 hypotheses of Sir Harry Johnston to account for the absence of 

 Tsetse-fly disease from the Uganda Protectorate, and goes to 

 support the suggestion at the end of Chapter I. that systematic 

 ettbrts should be made to study the geographical distribution of 

 the parasite of Nagana, as existing in the blood of wild animals 

 in Africa, by means of Colonel Bruce's method of injecting blood 

 from the latter into domestic animals. | 



As to the ([uestion whether the parasite of Nagana can be 

 conveyed by blood-sucking flies other than the Tsetse, it may be 

 remarked at the outset that were this the case to any large extent 

 the disease would probably be of much more general occurrence. 

 Nevertheless, a certain amount of evidence undoubtedly exists, 

 which, if reliable, can only be interpreted in one of three ways : 

 either the Tsetse occurs in localities where it has not yet been 

 identified, and the deaths of domestic animals ascribed by natives 

 to the agency of other and unknown flies are really due to it ; or 

 blood-sucking flies other than Glossina may in certain localities, 

 and perhaps only at certain seasons, convey a hyematozoon which 

 is either that of Nagana or an organism closely related to it ; or, 

 lastly, the disease in these cases, whatever it may be, is quite dis- 

 tinct from Nagana, and is possibly, like Texas fever, disseminated 

 by means of ticks. According to Marno [47]> the assertion that 

 " in certain parts of Africa at certain seasons domestic animals 

 are killed by the poisonous bites of flies, which in some countries 

 even make the keeping of particular domestic animals impossible," 

 has been constantly repeated since the time of Agatharchides.§ 



* Cf. [94, 124, 133, 150, 171]. 



t A survey party to which Mr. Eckersley was attached took two Natal 

 ponies through the Fly-belt between Beira and Chimoio without any 

 ill-effects to the animals, although Tsetse-flies (in this case doubtless 

 Gl. morsitans) settled on them in considerable numbers. 



J Cf. Chapter I., p. 30, note f, and Appendix A, p. 280. According to 

 Mr. R. J. Stordy (see Appendix C, p. 292), a parasite "the morphology of 

 which was identical with that found in animals suffering from Tsetse-fly 

 disease " occurs in ]\Iombasa in donkeys, which have never left the island, 

 although the Tsetse is said not to be found there. 



§ " Agatharchides ('AyaOapx'iSris) or Agartharcus {' Ayddapxas) , a Greek 

 grammarian, born at Cnidos, lived at Alexandria, probably about b.c. 130. 

 He wrote a considerable number of geographical and historical works ; but 

 we have only an epitome of a portion of his work on the Erythraean Sea, 

 which was made by Photius. It is printed in Hudson's Geogr. Script. Gr. 

 Minores." — Sinitlt's Classical Dictionary. 



