432 



Col. Sir D. Bruce and others. Trypanosome [May 24, 



But when we compare the curves representing the distribution by 

 percentages in respect to length of 1000 and 1220 individuals of each 

 species, the similarity of the two parasites is remarkable. In T. brucei 

 there are 26 per cent, non-flagellated forms, in the trypanosome of Nyasaland 

 25 per cent. 



Again, if we divide the 1220 Nyasaland trypanosomes, by length, into 

 short and stumpy (13-21 microns), intermediate (22-24 microns), and long 

 and slender (25 microns and upwards), as has been done in the case of 

 T. brucei and T. gambiense, the result is as follows : — 





Short and stumpy. 



Intermediate. 



Long and slender. 





51 -2 



23 -1 



25 -7 



T. brucei 



32 -8 



25 "5 



41 -7 



Nyasaland trypanosome 



30 -8 



18 -4 



50 -8 



This shows the percentage of the short and stumpy to be almost the same 

 in T. brucei and the Nyasaland trypanosome, and the latter to be rather 

 better off in the long and slender forms. 



Comparison of the Trypanosome of the Human Trypanosome Disease 

 of Nyasaland with T. rhodesiense (Stephens and Fantham). 

 Dr. J. W. W. Stephens, of the Liverpool School of Tropical Medicine, at 

 Sir David Bruce's request, kindly measured 1000 trypanosomes of the strain 

 from a case of Sleeping Sickness from the Luangwa Valley, North-east Bhodesia, 

 which he has named T. rhodesiense. This proposed new species is characterised 

 by posterior nuclear forms, and a snout-like prolongation of the posterior 

 extremity. These are also, as we have seen, characteristics of the Nyasaland 

 trypanosome. The following chart has been prepared from the figures 

 supplied by Dr. Stephens, and shows that the similarity of the curve 

 prepared from 1000 individuals of T. rhodesiense to that prepared from 

 1220 individuals of the Nyasaland trypanosome is still more remarkable 

 than in the case of T. brucei. Dr. Stephens measured 100 trypanosomes 

 from man, 40 from the monkey, 40 from the horse, 40 from the dog, 40 from 

 the rabbit, 100 from the guinea-pig, 600 from the rat, and 40 from the 

 mouse. 



