460 



M. E. COLLETT 



its position at the top of the list, the other cyclic and the fatty 

 acids (except formic) stand next, while the hydroxy acids and 

 hydrochloric are much less toxic than the rest. Evidence of like 

 nature has been obtained in experiments upon very different 

 sorts of material. In every case the relative efficiency of equi- 

 normal solutions failed to parallel their H ion concentration 

 exactly, and solutions of equal Ph were always unequal in effect. 

 Only one conclusion is possible. The H ion is an important 

 factor in the physiological effects of acids, but at least in organic 

 acids some other factor or factors are involved which makes 

 them more effective than their Ph alone would lead one to 

 expect. 



