1912.] Reservoir for Trypanosoma gambiense. 



307 



From June 3 to 10, 1911, 10 months after last evidence of infectivity, this 

 antelope was fed upon daily by Experiment 22. It was desired to ascertain 

 whether any degree of immunity to T. gambiense had been acquired, with a 

 view to further experiments with the serum. Bushbuck 2328 has, with the 

 exception of the first few months after infection, always proved negative. As 

 in the case of Waterbuck 2378, the last evidence of infectivity was obtained 

 some four months after infection, the other bushbuck and reedbuck remaining 

 infective for some considerable time longer. It appeared therefore very 

 probable that the trypanosome had died out in this particular antelope. 



Fly Experiments. 







Number of flies. 



Length 



of 

 experi- 



in 



Result 



of 

 feeding 



clean 





Expt. 

 No. 



Period for which 

 flies fed upon 2328. 



1st 



30th 

 day. 



Dissected 

 during 



Con- 

 taining 

 flagel- 



Remarks. 



194 



206 



July 12—17, 1911 

 July 18—25 „ 



76 

 95- 



65 

 78 



76 



95 





 



50 

 48 





Fed ou monkey through- 

 out the experiment. 





Totals 



171 



143 



171 



























Experiment 194 was fed upon cock's blood during the earlier part of the 

 experiment. 



Injection Experiments. 



Date. 



Expt. No. 



Quantity of blood injected. 



Result. 



Animal used for 

 injection. 



Pure. 



Citrated. 



18.4.11 



8 

 9 



c.c. 



c.c. 

 14 

 4 k 





White rat. 

 Monkey. 



18.4.11 



28.6.11 



176 

 177 



244 

 638 



5h 



1 



Hi 





Monkey. 

 White rat. 

 Monkey. 



28.6.11 



3.8.11 



6.2.11 



In the above table the line indicates the demarcation between experiments 

 carried out before and after the attempt at re-infection in June, 1911. It 

 will be seen that in no case did infection result. This antelope thus appears 

 to have acquired a certain degree of immunity to T. gambiense. 



