Gb H. F. Nuttall 
205 
The number of trypanosomes counted for every 1000 red blood 
corpuscles in a stained film of peripheral blood gives an adequate idea of 
the degree of infection both before and at various times after treatment. 
Thus in Mouse I. there were 12 trypanosomes per 1000 r. b. c. present 
in the blood before treatment. Two hours after treatment the propor¬ 
tion was 8 : 1000, and after 5 hours only 0'2 : 1000. No parasites were 
subsequently discovered. 
Whereas before treatment 95 °/ 0 of the trypanosomes contained no 
dark red or purplish spherical granules in their blue-staining proto¬ 
plasm, and 92 °/ 0 showed blue-staining protoplasm protruding beyond 
the blepharoplast in the characteristic beak-like manner (Diagram 2, 
Fig. 1), already one hour after treatment only 5 °/ 0 of the parasites 
were free from granules and none showed the beak-like process 
posteriorly. After two hours all of the trypanosomes showed granules 
(Diagram 2, Figs. 2, 3). As will be seen from the table, the proportion 
of trypanosomes containing 1—2 or 3—5 granules was very high one 
hour after treatment, but their number became less subsequently. 
On the other hand, the proportion of trypanosomes containing many 
granules increased after the second hour and decreased slightly after 
the third hour. After three hours no less than 12 °/ 0 of the trypano¬ 
somes stained faintly (Fig. 4), some taking on a violet tint, whilst 9 °/o 
had become rounded or were breaking up. After five hours (Figs. 
5—7) only a few pale-staining parasites, fragments of parasites, or loose 
flagella could be found. During the first three hours after the admini- 
stration of the drug 21 to 29 °/ 0 of the trypanosomes were found in 
various stages of longitudinal division as evidenced by the existence of 
two blepharoplasts and partial separation into two of the flagellar 
filament. These dividing forms, however, showed the same appearances 
of degeneration as those described above for the ordinary single 
parasites. 
A second experiment was now carried out as follows. Two mice, 
each weighing about twenty grammes were inoculated at 10 a.m. on 
15. ii. 1910 with a small amount of blood obtained from the tail of a 
mouse infected with Tr. brucei. A very few r trypanosomes were detected 
in the blood of both mice on 17. II. Counts of the number of trypano¬ 
somes in the blood of these mice were made commencing on 18. n., 
blood-films being prepared at intervals as stated in the protocols. One 
mouse (II.) was treated with arsenophenylglycin while the other (III.) was 
left untreated. There were 10 trypanosomes per 1000 r.b.c. present in 
the blood of the mouse (II.) immediately before treatment; blood-films 
