A. P. MATHEWS 



work any ion can do must depend upon its available potential energy ; 

 i. e., upon the product of the difference of potential between the 

 protoplasm and the ion multiplied into the quantity of energy 

 transferred before the potentials were equalized. Of two positive 

 ions holding different quantities of available potential energy, that 

 which has the more energy can do the more work. The total amount 

 of work any number of positive ions can do will depend on the con- 

 centration of the the ions and amount of available potential energy in 

 each ion. If we take as a standard a certain amount of work let us 



X = Ionic Potential. 



FIG. i. Ordinates represent the dilution of the minimum fatal dose 

 Abscissae represent the cation potential. 



