Recovery of T. gambiense from Tragelaphus spekei. 483 



observed and distinguished from those clumped. In some culture tubes, 

 rounded (involution) forms appear in great numbers on the third day to the 

 fifth day, and the virulence and properties of these forms are now being 

 separately studied. 



The percentage of successes varies very much indeed — from 1 tube in 25 to 

 6 in 6. Numerous other media have been used, giving invariably negative 

 results by the fifth day, including those consisting of frozen and thawed 

 rabbits' blood serum only. 



Further Observations on the Recovery of Trypanosoma gambiense 

 from Tragelaphus spekei on the Islands of Lake Victoria 

 Nyanza 



By Dr. H. L. Duke. 



(Communicated by Sir John Rose Bradford, K.C.M.G., Sec. R.S. Received 

 July 17, 1912.) 



In a paper* dealing with the recovery of a trypanosome from wild antelope 

 on Damba Island, Lake Victoria Nyanza, the diagnosis is discussed at some 

 length with a view to the exclusion of T. brucei. 



Fifteen subinoculation experiments were considered and the conclusion was 

 arrived at that the available evidence pointed to the organism being 

 T. gambiense. After a lapse of some four months this opinion has received 

 considerable support from a more prolonged investigation of the animal 

 reactions of the trypanosome. In the following table many of the original 

 subinoculations are followed to their conclusion on the death of the animal, 

 and several other experiments have been added to the list. 



It will be seen that the evidence supplied by the rat experiments is strongly 

 in favour of T. gambiense. 



In the six experiments conducted with rats the average duration of the 

 disease is 61 days. This constitutes very strong evidence against T. brucei. 

 In guinea-pigs (three experiments) the average duration is 67 days : in five 

 completed monkey experiments, 147 days. 



* ".Antelope and their Relation to Trypanosomiasis," 'Roy. Soc. Proc.,' B, vol. 85, 

 p. 15Q. 



