XVIII] TRANSMISSION 339 



placed in a partially dehydrated atmosphere. They were fed 

 every day on a healthy kid until the ninth day when they were 

 dissected and four were found to be infected. In another 

 similar experiment three out of fifteen flies became infected 

 and the kid succumbed to trypanosomiasis caused by their 

 bites In two control experiments, during which the flies 

 were kept in the ordinary atmosphere, eight out of twelve and 

 eight out of nine flies shewed flagellates and also infected a 

 succession of healthy kids on which they were fed. 



In another experiment, six flies hatched from pupae that 

 had been kept in dry air from their formation, were fed 

 on July 7, 8, and 9 on an infected goat and then returned 

 to dry air. On the i8th and I9th they were allowed to bite a 

 healthy kid and on the 27th and 28th yet another normal kid. 

 The next day the flies were dissected and two out of six were 

 found to be infected, moreover both kids suffered from a very 

 severe attack of trypanosomiasis. Roubaud accordingly is 

 of the opinion that if the modifying influence, such as dry air, 

 acts for a long time before the infecting feed is given, the 

 saliva regains its suitability as a medium for the development 

 of the trypanosomes. 



The action of saturated air was similarly tested and respec- 

 tively, one fly in eight and one infifteen became infected, without, 

 however, infecting a kitten on which they were fed. These 

 results tend to explain the author's observation that, in nature, 

 during the dry season more flies were found to be infected than 

 during the wet. 



REFERENCES. 



Bouet and Roubaud (1911). Bull. Soc. Path. Exot. vol. iv. p. 539. 

 Bouffard, G. (1909). Bull. Soc. Path. Exot. vol. n. p. 599. 



(1910). Ann. Inst. Pasteur, vol. xxiv. p. 276. 



Cazalbou, L. (1905). Compt. Rend. Soc. Biol. vol. LVIII. pp. 564-565. 

 Laveran, A. (1906). Compt. Rend. Acad. Sci. vol. CXLIII. pp. 94-97. 



(1910). Bull. Soc. Path. Exot. vol. in. p. 80. 

 Rodhain, Pons, van den Branden and Bequaert (1912). Bull. Soc. Path. 



Exot. vol. v. pp. 45-50 and 281-84. 



Roubaud, E. (1909). These de doctor at es sci. nat. Paris, June, 1909. 

 (1910)- Compt. Rend. Acad. Sci. 1910, pp. 729-32. 



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