510 Description of a Strain of T. brucei from Zululand. 



go a good long way to make the ordinary unprejudiced man chary of exposing 

 himself too carelessly to the so-called harmless nagana. His serum may save 

 him as a rule, but there may come a time when — his resistance being lowered 

 either by fatigue, or some other cause — the trypanosome may gain a footing, 

 and then his belief in the written word of the text-book will receive a rude 

 shock. 



Breadth. — The long and slender average 2*76 microns in breadth, the 

 intermediate 3 - 25, and the short and stumpy 3 "53. This measurement was 

 made across the broadest part of the trypanosome and includes the 

 undulating membrane. Most previous measurements of breadth have not 

 included this. 



In regard to the shape of this trypanosome, contents of cell, nucleus 

 micronucleus, undulating membrane, and flagellum, it is not proposed to 

 describe these characters separately for this strain as was done in the case of 

 the trypanosome causing disease in man in Nyasaland. Suffice it to say that, 

 after the most careful comparison, no difference whatever can be made out in 

 the morphology of the two trypanosomes. At the end of this paper three 

 plates are given, one representing the short and stumpy, another the inter- 

 mediate, and a third the long and slender forms. If these plates are 

 compared with those given in previous papers* it will be seen that in 

 morphology the Nyasaland and Zululand trypanosomes are identical. 



Conclusions. 



1. The trypanosome described in this paper under the name of the 

 "Zululand strain, 1913," is the same species as that discovered by Bruce in 

 Zululand in 1894 ; reported on by Kanthack, Durham and Blandford in 

 1898 ; and named T. brucei by Plimmer and Bradford in 1899. 



2. As regards its morphology, this trypanosome is absolutely identical with 

 the trypanosome causing disease in man in Nyasaland, the T. rhodesiense of 

 Stephens and Fantham. 



DESCRIPTION OF PLATES. 

 Plate 21. 



Trypanosoma brucei, Zululand strain, 1913, short and stumpy forms, x 2000. 



Plate 22. 



Trypanosoma brucei, Zululand strain, 1913, intermediate forms, x 2000. 



Plate 23. 



Trypanosoma brucei, Zululand strain, 1913, long and slender forms, x 2000. 



* 1 Roy. Soc. Proc.,' B, vol. 85, p. 433 (1912), and vol. 87, p. 35 (1913). 



