1912.] Causing Disease in Man in Nyasaland. 431 



The above table shows that 81 of the intermediate forms are under 

 22 microns in length, and that seven short and stumpy forms are above 

 21 in length. If the trypanosomes are separated into non-flagellar and 

 flagellated, then there are 24-8 per cent, of the former and 75"2 per cent, of 

 the latter. 



Comparison of the Trypanosome of the Human Trypanosoma Disease 

 of Nyasaland with T. bruoei. 

 The coloured plate which accompanies this paper, when compared with 

 that of T. brucei* or T. gambiense^ shows that the three species are much 

 alike. The chief difference is the tendency of the Nyasaland trypanosome, 

 as has already been pointed out, to show numerous posterior nuclear forms. 

 The Commission has had no opportunity of examining T. brucei for posterior 

 nuclear forms under the same conditions as the Nyasaland organism, but it 

 may be assumed that T. brucei does not show these aberrant forms to the 

 same extent, or the fact would have been noted long ago, no species having 

 been studied so often or so closely as T. brucei. Another difference between 

 the two species is the occurrence of the broad, blunt-ended forms — the 

 hippo-heacled— among the short and stumpy, a form which rarely, if ever, 

 appears in Bruce's trypanosome. 



Chart 2.— Chart giving Curves representing the Distribution, by Percentages, in respect 

 to Length, of 1000 Individuals of T. brucei, and 1220 Individuals of the Trypanosome 

 of the Human Trypanosome Disease of Nyasaland. 





Microns. 





13 



14 



15 



16 





xS 



19 



20 



Zl 



22 



23 





25 



26 







2S 







3- 



.'53 



34 



35 



36 



37 



























































12 























































II 























































IO 



























































to 























/ 



N 































<6 8 

 c 7 















A 





* 



/ 







■4 





\ 





V 





















I 6 













V 









V 



































Q- 5 























































4 











* 

























X 





















3 























































z 









y 















































I 





=5* 



.jf 

















































— Trypanosoma brucei ?ooo . 



^ Trypanosott&e of Jfyasaland /zzo. 



* < Eoy. Soc. Proc.,' 1911, B, vol. 83, Plate 2. 

 t Ibid., vol. 84, Plate 13. 

 VOL. LXXXV. — B. 2 H 



