Strain of T. brucei from Zululand. 



505 



From this curve it will be seen that three passages through G. morsitans 

 has had little or no effect in changing the character of this trypanosome as 

 regards distribution of length. It has usually been thought that a trypano- 

 some kept under laboratory conditions, and without the opportunity of 

 passage through its invertebrate host, the tsetse fly, would tend to change 

 in morphology. These curves, on the other hand, show that a trypanosome, 

 after passage through horses and cattle for some years — exact time unknown 

 — is unchanged by three passages through its invertebrate host, G. morsitans. 



Table IV. — Distribution in respect to Length of 500 Individuals of T. brvxei, 

 Zululand Strain, 1913, after first passage through G. morsitans. 

















In microns. 























































A TPM OTA 

 - i > ciu n 



Animal. 

























































26. 















1 pti trt".}! 





16. 



17. 



18. 



19. 



20. 



21. 



22. 



23. 



24. 



25. 



27. 



28. 



29. 



30. 



31. 



32. 



Rat 





1 



1 



5 





2 



1 



1 



4 



1 





2 





2 









22 - 5 











1 



3 





4 



3 



1 



3 





1 



3 





1 





— 



23 -8 





— 



1 



3 





1 



4 



2 



4 



1 



1 



1 





1 



1 





— 





22 1 









3 





5 



2 



3 



3 



1 



2 









1 









21 -7 







1 



1 



1 



2 



6 



3 



1 



4 









1 











21 -4 





— 





2 





3 



6 



4 



2 



2 



1 

















21 -4 











3 



4 



4 



2 



2 



1 



1 





1 



1 









1 



22 3 









3 



1 



8 



3 





1 



1 



2 





1 













21 -0 









3 



3 



5 



1 



2 



2 









2 





2 









21 -7 









2 



2 



1 





; 



2 



2 



1 



1 





2 



4 



2 







24 -6 











3 



3 



1 







2 



4 



1 





1 



2 





1 



1 



24 -1 









1 



2 





1 





3 



4 



4 



1 



1 



1 



2 









24 -0 









2 



4 



1 



1 



4 





2 



3 





2 







1 







22 -4 









1 



1 



1 



1 



2 



2 



5 



3 



2 







1 





1 





23 -7 











1 



1 



2 



2 



3 



3 



3 



2 



1 





1 









23 3 







2 



I 



2 



1 



3 



1 



3 



2 



1 





2 





1 









21 -9 







1 



3 



1 



I 



3 



4 







4 







2 











2L "8 









2 



3 





5 



1 



5 





1 





1 













21 -3 









1 



5 





5 



1 









2 



1 





1 









21 -4 





1 





1 



1 



3 



3 



2 



4 



1 



1 







2 











22 3 









1 



5 



1 



4 



2 



1 



3 





1 







1 









21 9 









1 



4 



5 



4 



1 



2 





1 





1 



; 











21 3 









1 



2 



3 



5 



2 



2 



1 



1 



1 



1 





1 









22 -1 











1 



4 



4 



3 



1 



2 



2 



1 





i 





1 







22 7 







1 



3 



5 



4 



1 



~~ 





1 





2 



1 



2 











21 -3 



Total 



1 



7 



38 



56 



67 



71 



48 



47 i 



43 



40 



15 



18 



19 



21 



5 



2 



2 





Percentages . . . 



0-2 



1-4 



7-6 



11 -2 



13 -4 



14 -2 



9-6 



9-4 



1 



8 6 



8-0 



3 



3 6 



3-8 



4-2 



H 



0-4 



0-4 





