The action of atoxyl. 



4i 



That the motility of trypanosomes is preserved longer in serum 

 than in salt solution was noted years ago and has recently been 

 emphasized by Schern, 1 but the writer is not aware that anyone 

 has previously recommended suspending trypanosomes in serum 

 for experiments in vitro. 



31 (640) 

 The action of atoxyl. 

 By B. T. TERRY. 



[ From the Laboratories of the Rockefeller Institute for Medical 

 Research, New York. 



The action of atoxyl is paradoxical. In vivo it is effective 

 against certain parasites, in vitro it has little or no action. Ehrlich 

 believes that the medicament must be reduced in the body before 

 it becomes active. This view has been strengthened by Levaditi 

 and Yamanouchi who have shown that emulsions of liver, muscle, 

 and lung, when incubated with atoxyl, transform this medicament 

 into a toxic substance. Levaditi apparently believes that the 

 transforming agent is in the liver and other organs, while Yaman- 

 ouchi concludes that it is in the red blood cells only. My results 

 confirm much of the experimental work of Levaditi and Yaman- 

 ouchi, but lead to a conclusion that, in its entirety, is apparently 

 held by neither of these investigators. 



In my experiments, both liver and blood when incubated with 

 atoxyl (10 per cent.) at 37 degrees for 3 hours, transformed this 

 medicament into a toxic substance. 



The transforming agent in liver had characteristics, however, 

 which in some respects were quite different from those of the 

 active agent in blood. 



The active agent in liver was soluble in salt solution, was filter- 

 able through collodium, and was quite resistant. Liver emulsion 

 ground with sand in a mortar, or heated to 100 degrees for 10 m., 

 lost little or none of its activity. The addition of blood to liver 

 emulsion before incubation with atoxyl increased its activity, but 

 liver emulsion washed thoroughly to free it of red blood corpuscles 

 was inactive, probably because of the solubility of the transforming 

 agent. 



From the blood the active agent was apparently not extract- 



1 "Arbeiten aus dem kaiserlichen Gesundheitsamte," Berlin, 1911, xxxviii, 338. 



