230 Drs. J. W. W. Stephens and H. B. Fantham. [Mar. 28, 



This table also appears to indicate that there are some differences in size 

 between T. gambiense and T. rhodesiense. 



If now the 1000 T. rhodesiense are divided according to length into three 

 groups— (a) short and stumpy forms of 13 to 21 microns, (b) intermediate 

 forms of 22 to 24 microns, and (c) long and slender forms of 25 microns and 

 upwards (as has been done by Sir David Bruce in his researches on trypano- 

 sonies), and comparison of them with Bruce's results for T. gambiense and 

 T. brueei be made, the following percentage distributions are obtained : — 



Table V. 





Short and stumpy, 



Intermediate, 



Long and slender, 





13—21 ft. 



22— 24 M . 



25—39 fi. 





per cent. 



per cent. 



per cent. 



T. gamliense 



51 "2 



23-1 



25 -7 





32 -8 



25 -5 



41 -7 



T. rhodesiense 



36 -1 



19 -8 



44 -1 



We note that T. rhodesiense is richest in long and slender forms and poorest 

 in intermediate forms. 



If the percentages in the three groups are calculated for (i) each of the 

 hosts infected with T. gamliense recorded in Bruce's Table III, and for (ii) 

 each of the hosts infected with T. rhodesiense recorded in our Table I, then 

 large variations are found to occur. Thus, from a comparison of 1000 

 T. gambiense, measured from seven species of animals by Bruce, on a variety 

 of [days, and 1000 T. rhodesiense, measured by us from eight species of 

 animals on a variety of days, the following results are obtained : — 



Table VI. 



T. gambie 



T. rhodesiense. 



13-21 

 22—24 



per cent. 

 32 -0 to 82 -1 

 14 -3 to 33 -3 

 3 -6 to 52 -0 



per cent. 

 28 -0 to 80 

 7 "5 to 37 -5 

 5 -0 to 57 -5 



Also the following table summarises the variation in 240 T. rhodesiense 

 from the same rat (Table I, Eat B 16) from the 4th to the 13th day of 

 infection. 



