1913.] causing Disease in Man in Nyasaland. 299 



Table XVII. — Measurements of the Length of the Trypanosomes of the five 

 Human Strains. The trypanosomes have been taken from various animals. 



Date. 



Strain. 



Name. 



Number 

 of 



trypano- 

 somes. 



Animals. 



ji. v critic 



length. 



In microns. 



T^Ta ti m n tti 



j UAllU ill! 



length. 



jMimmum 

 length. 



1912 



I 



Mkanyanga 



1220 



Various 



24 -1 



36 -0 



14 -0 



1912 



II 



E 



1500 





22 -2 



36 -0 



15 -0 



1912 



III 



Chituluka 



1500 



j) 



26 -1 



38 



15 -0 



1912 



IV 



Chipochola 



1000 





22 -5 



34 -0 



15 -0 



1912 



V 



Chibibi 



1000 



» 



22 -4 



37 -0 



15 









6220 





23 -5 



38 -0 



14 -0 



It must be acknowledged that, in spite of the fairly large number of 

 trypanosomes measured, there is a marked difference in the average length 

 of the five human strains — from 22 - 2 to 26'1 microns. Strains II, IV and V 

 are similar, varying only from 22"2 to 22 - 5. 



This difference in average length may be due to slight variations having 

 taken place in the different strains, resulting from the passage through more 

 or less resistant man. There is no evidence that this variation is due to 

 treatment by atoxyl or other drugs. It has been shown that the same 

 strain grown in two animals of the same species gives like results. 



Table XVIII. — Measurements of the Length of the Trypanosomes of the 

 five Human Strains. The trypanosomes have been taken from the rat 

 alone. 









Number 

 of 



trypano- 

 somes. 





In microns. 



Date. 



Strain. 



Name. 



Animal. 



Average 

 length. 



Maximum 

 length. 



Minimum 

 length. 



1912 

 1912 

 1912 

 1912 

 1912 



I 

 II 

 III 

 IV 



V 



Mkanyanga 



E 



Chituluka 



Chipochola 



Chibibi 



600 

 1000 

 1000 

 500 

 500 



Eat 



>! 

 J> 

 >t 

 >i 



25 -1 



23 -1 

 26*4 

 22 -5 



24 -0 



35 -0 

 32 -0 

 38 -0 

 34 -0 

 32 -0 



16 -0 



17 -0 

 15 -0 

 15 -0 

 18-0 









3600 





24 -2 



38 -0 



15-0 



VOL. LXXXVI. — B. 



Y 



