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M. E. COLLETT 



ever, is limited by the increasing toxicity of the salt itself. The 

 decrease in toxicity in the acid-salt mixtures is of course due 

 largely to diminished pH. 



It is interesting to note that the decrease in many cases is less 

 than would be expected. Thus, in formic acid plus 0.05 M 



TABLE 2 

 Toxicity of Na salts with and without their acids 



Na-f ormate Euplotes lives eight minutes, although in Na-f ormate 

 alone it lives sixty minutes and in HCl (of the same pH as the 

 mixture) 80 minutes. Other examples are given in the table 3. 

 The length of life in acid plus salt of non-toxic concentration is 

 less than the pH would indicate in the case of all the monobasic 



