62 



Sir D. Bruce and others. Try pano some 



In Experiment 1477 a portion of the intestine of the infected fly was 

 inoculated subcutaneously into a pig ; the pig did not become infected. 



Out of a total of 173 flies used in these experiments, 10 flies (5'8 per cent.) 

 became infected with a growth of trypanosomes in the intestines and in the 

 probosces. It will also be seen that only 1 fly in 31 (2 - 7 per cent.) 

 became infective when the flies were kept at ordinary room temperature, 

 whereas 4 became infected in 45 (9 per cent.) when the flies were kept at a 

 temperature of 28° C. 



General Considerations regarding the Development of T. simle in 



G. morsitans. 



All the flies dying during the progress of the experiments were dissected. 

 In the two positive experiments, out of 76 flies dissected, nine infected flies 

 were found. The following table gives the results of the dissection of these 

 nine flies : — 



Table VI. 



1 





Proboscis. 



















Time, 







Proventri- 





Fore- 



Mid- 



Hind- 



Procto- 



Salivary 



Expt. 







Crop. 



days. 



Labial 

 cavity. 



Hypo- 

 pharynx. 



culus. 



gut. 



gut. 



gut. 



deum. 



glands. 



754 



37 



+ + 





+ + 





+ + 



+ + 









754 



50 



+ + 





+ + 





+ + 



+ + 









1847 



16-26 











+ + 



+ + 









1847 



30-40 



+ 



+ 







+ + 



+ + 









1847 



31-41 



+ + 



+ 



+ + 





+ + 



+ + 



+ + 







1847 



31-41 



+ + 





+ 





+ + 



+ + 



+ + 







1847 



31-41 



+ + 



+ 



+ 





+ + 



+ + 









1847 



32-42 



+ + 



+ 



+ 





+ + 



+ + 



+ + 







1847 



32-42 







+ 





+ + 



+ + 









From this table it will be seen that in seven out of nine flies dissected the 

 labial cavity is found to contain trypanosomes. This is very different from 

 what is seen in the similar table relating to T. gambiense. There not a 

 single case of infection of the proboscis is recorded.* 



At what stage in the development of the trypanosome the proboscis takes 

 a part is not known. It is probable that the infection commences in the 

 intestinal tract and moves forward into the proboscis, but owing to the 

 difficulty of obtaining sufficient laboratory-bred G. morsitans the Commission 

 have not, up to the present, enough evidence to establish this detail. 



In the two infected flies found in the cage of flies, Experiment 754, it is 

 to be regretted that the contents of the hypopharynx were not noted, but 

 * 'Eoy. Soc. Proc.,' 1911, B, vol. 83, p. 516. 



