156 Dr. H. L. Duke. [Feb. 26, 



products of the liver cells, preferably the bile pigments, carrying them 

 to the malignant growth. Hence the latter may wear both on its surface 

 and in its interior a distinct yellow appearance, due to the aggregation of 

 " jaundiced " pyrrhol cells. Since the tumour evidently surfers through the 

 application of the above-mentioned substances, it does not seem improbable 

 that the pyrrhol cell is also active in transporting substances to the tumour 

 which impede, and in many cases stop, its growth. 



Antelope and their Relation to Trypanosomiasis. 

 By Dr. H. L. Duke. 



(Communicated by Sir J. R. Bradford, Sec. R.S. Received February 26, — Read 

 March 28, 1912.) 



[Plate 2.] 



The flies on the Chagwe Lake shore are still capable of infecting monkeys 

 with Trypanosoma gambiense. Four years and a-half have now elapsed since 

 the Chagwe coast line was officially declared free of population, all villages 

 destroyed within a zone of two miles bordering the lake, and their inhabitants 

 removed inland. In spite of precautions, however, there is very little doubt 

 that the islanders continued secretly to visit the mainland until they also were 

 removed in 1909, and all the island villages destroyed. Since September, 1909, 

 therefore, there have been no natives in the fly area except the recalcitrant 

 few, who, at the risk of imprisonment, may from time to time return to their 

 old haunts on the mainland or the islands. Instances of this have indeed 

 occasionally occurred up to the time of writing. Apart from the captures 

 made by the Government patrol, I have on several occasions had to report 

 signs of recent native occupation within the prohibited area seen in the 

 course of excursions from Mpumu. 



In considering the question of the infectivity of the lake-shore flies, the 

 possibility of infected natives being available as a food supply must still be 

 considered, although this factor is apparently of small importance. These 

 natives would most likely only venture forth at night time, and would be 

 unlikely to approach the fly ground, which is visited almost daily by the boys 

 from Kibanga. There remain the canoemen and fly-boys employed by the 

 Laboratory, and in this connection it can only be said that, although 



