1908.| Have Trypanosomes an Ultra-microscopical Stage? 397 
Haperiment 29. 
March 27, 1908.—A white rat, whose blood was swarming with 7’. evansi, was injected 
with 4 c.c. of a }-per-cent. solution of sodium antimony] tartrate. This rat died half an 
hour after receiving the dose. Emulsion of the organs and bone-marrow made and 
filtered in the usual way, and 1 cc. of the filtrate injected into two white rats. 
April 29, 1908.—Both rats remain well. 
Experiment 33. 
March 30, 1908.—A white rat, whose blood was swarming with 7’. evansi, was injected 
subcutaneously with 4 ¢.c. of a }-per-cent. solution of sodium antimony] tartrate. This 
treatment was continued for a month, the animal receiving in all 11 doses. 
May 4, 1908.—Rat killed and its organs and blood emulsified and filtered. Half a 
cubic centimetre of the filtrate was injected intra-peritoneally into two rats. 
June 4, 1908.—Both rats healthy. 
Experiment 66. 
_ March 8, 1908.—A white rat, whose blood was swarming with 7’. brucez, was injected 
with two drops of a 1-per-cent. solution of sodium antimonyl tartrate. This treatment 
was continued for a month, the animal receiving in all eight doses. 
April 10, 1908.—Rat killed and its organs emulsified and filtered in the usual way. 
‘One cubic centimetre of the filtrate injected into two rats. 
May 11, 1908.—Both rats healthy. 
Experiment 19. 
March 8, 1908.—A. nagana rat, whose blood was swarming with 7. brucez, was injected 
on the third day of disease with 2 minims of a 1-per-cent. solution of sodium antimonyl 
tartrate. 
March 9, 1908.—Repeated injection. A few trypanosomes in blood. 
March 11, 1908.—Repeated injection. A few trypanosomes in blood. 
March 13, 1908.—No trypanosomes in blood. 
March 18, 1908.—Blood swarming with trypanosomes. Injected 4 c.c. of a t-per-cent. 
solution of sodium antimony] tartrate. Rat died five minutes later. Organs emulsified 
and filtered and 4 c.c. of the filtrate injected into a white rat. 
March 26, 1908.—This rat’s blood is found to be swarming with trypanosomes. It is 
evident that something has passed through the filter capable of infecting a rat with 
nagana ; but it is possible that the filter has become defective on account of wear. It 
was tried again with a cultivation of Micrococcus melitensis in broth and failed to keep 
back the micrococci from the filtrate. It was, therefore, concluded that the filter was 
defective, and this experiment null and void. 
Conclusion. 
From these experiments it may be concluded that the blood of white rats 
suffering from nagana and treated for varying times with antimony salts 
does not contain ultra-microscopical forms of 7. brucez. 
