62 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
gangrenous, in such a part very few parasites will be found although the blood above 
the area may be swarming. Moreover, the movements of the parasites are slow and 
show degeneration and deformity, whilst phagocytes will be found containing the 
remains of trypanosomes. Acting on these observations experiments have been made 
with various bacteria. Guinea-pigs suffering from tuberculosis seem to be somewhat 
more susceptible to trypanosome infection than healthy ones. Mice, already infected 
with trypanosomes, and then inoculated with B. anthracis and the B. sui, show at times 
a certain amount of retardation of the disease. The parasites do not appear to 
augment so rapidly. Ordinary cultures of pyogenic cocci are too virulent for 
the animal. If a very attenuated culture of Staphylococcus pyogenes aureus is 
inoculated with T. dimorphon, the animals show a marked diminution in the number 
of parasites, but they persist for some days. Unfortunately, the subcultures never act 
in the same way and show increase in the virulency. In one or some eight rats 
infected with T. brucei and then injected with Leuconostoc mesenteroides there was a 
lessening in the number of the parasites ; this animal was subsequently injected 
intraperitoneally with a culture of Klasse's Gonodiplococcus of scarlet fever. The 
parasites disappeared, but the animal died one-and-a-half days later from a septic 
peritoneal infection due to the wounding of the gut. Cultures or B. typhi, B. coti, 
B. diphtheriae, so far as we have been able to observe, have proved of no avail. 
In connection with these observations it is interesting to record the work of Nissle ; 
unfortunately, only a review of his preliminary paper is available. He inoculated 
intraperitoneally a number of rats infected with the Nagana parasites with one-twentieth 
of a loopful of a B. prodigiosus culture grown on potato ; in twenty-four hours the 
trypanosomes disappeared, and some of the rats died from intoxication in half to three 
hours after injection. During the disappearance of the parasites he observed all kinds 
of endo-globular forms. It must be borne in mind that the injection of a culture 
causes a leucocytosis, and whether Nissle's results depend only upon this or upon the 
toxic products of the bacteria remains to be seen. It is hoped that this question will 
not be neglected. 
Conclusions 
From the experimental work with various therapeutic agents the following 
conclusions can be made : — 
1. That animals suffering from trypanosome infection react favourably to only 
a few agents, of which arsenic is the only drug which seems to exert a more than 
transient action. 
2. That the greater the amount of arsenic introduced into the system of the 
animal the greater and more permanent the effect on the parasite. 
3. That arsenic medication is indicated in the treatment of individuals suffering 
from Trypanosomiasis. That the treatment ought to be long continued and regularly 
