396 Col. D. Bruce and Capt. H. R. Bateman. [June 6, 
To ascertain uf the Filtered Blood of White Rats suffering from Nagana is 
infective. 
Experiment 40. 
December 17, 1907.—A white rat, suffering from nagana, and whose blood was swarming 
with 7. brucet, was killed to-day. The organs and bone-marrow were made into an 
emulsion with 1 per cent. sodium citrate in salt solution and filtered in the usual way. 
Half a cubic centimetre of the filtrate was then injected into the peritoneal cavity of a 
white rat. 
March 16, 1908.—This rat has never shown trypanosomes in its blood. 
Haperiment 41. 
December 17, 1907.—This rat was also injected with the same quantity of filtrate as in 
Experiment 40. 
April 1, 1908.—Trypanosomes have never appeared in the blood. 
EHaperiments 42 and 43. 
December 24, 1907.—A nagana rat, whose blood was swarming with trypanosomes, was 
killed and the organs, etc., emulsified and filtered. One cubic centimetre of the filtrate 
was injected intra-peritoneally into two white rats. 
March 30, 1908.—Both rats healthy. 
Experiments 44, 45, 46, 47, 48, 49, and 50. 
This procedure was repeated seven times in exactly the same way and always with a 
negative result. 
Conclusion. 
From these 11 experiments it would appear that the blood of nagana rats 
filtered through a Berkefeld filter is not infective. 
To ascertain vf the Filtered Blood of White Rats suffering from Nagana or 
Surra, and treated for various Periods with Antimony, is infective. 
It was thought that the effect of treatment on animals suffering from 
nagana might lead to the development of small resting forms of the 
Trypanosoma brucei which might be capable of passing through a Berkefeld 
filter. The effect of certain drugs on animals suffering from nagana is 
marvellous. The blood may be swarming with trypanosomes, yet within 
an hour of the injection not a single one can be seen. They may remain out 
of the blood for weeks or months, in some out-of-the-way place, and, perhaps, 
in some resistant form. 
Experiment 28. 
March 26, 1908.—A white rat, whose blood was swarming with 7’. bruce, was treated 
with 3 cc. of a 4-per-cent. solution of sodium antimony] tartrate. The rat died half an 
hour after receiving this dose. The organs and bone-marrow were emulsified and 
filtered in the usual way, and 1 c.c. of the filtrate injected subcutaneously into a white 
rat. 
May 7, 1908.—Trypanosomes have not appeared in the blood. 
