Different Amounts of Transformed Atoxyl Produced by Incubating One per Cent. and Ten per Cent. Atoxyl in Blood

1. 10 per cent. atoxyl in blood incubated at 37 degrees C. for 1 hour gives rise to a solution that is much more than ten times as toxic as a 1 per cent. solution of atoxyl similarly incubated. 2. When the comparison is made after incubation for 3 hours instead of for 1 hour, the toxicity of the 10 per cent. solution is but slightly greater than ten times that of the 1 per cent., provided the red blood corpuscles are not removed from the dilutions. 3. If the corpuscles are removed from both the 10 per cent. and the 1 per cent. atoxyl solutions immediately after incubation at 37 degrees for 1 to 3 hours, the dilutions of the 10 per cent. atoxyl are much more than ten times as toxic as the corresponding dilutions of the 1 per cent. atoxyl. 4. After incubation with atoxyl at 37 degrees for 1 to 3 hours, red blood corpuscles left at room temperature in dilutions made from the 10 per cent. and 1 per cent. solutions in blood increase markedly the toxicity of the dilutions made from the 1 per cent. atoxyl, but increase very slightly the toxicity of the dilutions made from the 10 per cent. atoxyl. 5. If one desires to produce a large amount of transformed atoxyl by incubating atoxyl in blood at 37 degrees for 1 to 3 hours, strong solutions of atoxyl should be chosen in preference to weaker solutions.