jfi8 
probable that injections of the Sodium salt of Araino-phenyl-stibinic 
acid would be far less irritating and permit the introduction of a larger 
amount of Antimony into the organism without toxic symptoms. 
After many unsuccessful attempts, we succeeded in preparmg the 
i>.ni. and o. amino-phenyl-stibinic acids. The action of the p. and 
compounds has been studied on experimental animals infected with 
various laboratory strains of pathogenic lr)panosomes; the o. 
compound was, after a few tentative experiments, given up as 
impracticable. 
I. EXPERIMENTS WITH m. AMINO-PHENYL-STIBINIC ACID 
ni. amino-phenyl-stibinic acid was used in the form of its acetylated 
derivative. This latter proved itself in the first experiments the less 
toxic, and produced no appreciable irritation at the site of inoculation, 
whereas the ui. compound caused marked swellings and abscesses. 
A. Rats. 
Medium-sized rats of the weight of 180-220 grammes were used 
for the following experiments. Untreated animals succumbed to an 
infection of T, brucei in 4-6 days on the average. Treatment was 
usually started when numerous parasites were present in the peripheral 
blood. In a few experiments the compound was injected only at a 
late stage, some hours before death ; but then the animal always died 
from the infection. The toxic dose was found to be 075 c.c. of a 
5 % solution ; an injection of 0-5 c.c. of the same solution corresponding 
to 0*025 gramme of the drug was usually well borne. No abscesses 
were noticed at the site of injection. After the administration of this 
dose the parasites disappeared from the blood in 12-16 hours. SmaUer 
doses were only able to effect a disappearance of the parasites from 
e 00 , when repeated The parasites, however, often reappeared 
comparatively short time ; a further injection of the drug again 
resulting in the disappearance of the parasites. 
able I shows the details of the result of treatment on thirty-three 
rats: only one rat is still living after 136 days. 
