INORGANIC SALTS 155 



irritability is ca 0.05 per cent, a value comparable with 

 that found for NaCl. Lithium chloride, nitrate, 

 sulphate, phosphate, and acetate all showed similar 

 action. All salts of the other alkali cations (NH4, K, 

 Rb, and Cs), in concentrations equivalent to 0.07 per 

 cent NaCl, promptly destroyed irritability. NaCl solu- 

 tions containing a little K and Ca (Ringer's solution) 

 were more effective in reviving irritabiHty than pure 

 NaCl solutions; irritability, however, was not sustained 

 by solutions containing Ca and K in the same propor- 

 tions, but sugar in place of NaCl. Na and Ca salts, 

 especially when both are present in the solution, antago- 

 nize the toxic action of potassium salts; this is readily 

 shown by using concentrations of KCl, which, acting 

 in pure solution, rapidly destroy irritabiHty. 



The addition of traces of CaCL and SrCla to isotonic 

 sugar solutions was found to delay the loss of irritabiHty, 

 and a slight revival was observed when sugar-muscles 

 were returned to weak solutions of Ca, Sr, Ba, or Mg 

 salts in isotonic sugar solution; but no restorative action 

 was observed in pure isotonic solutions of these salts. 



The results of experiments with nerve-trunks were 

 on the whole similar to those with muscle,^ although on 

 account of the structure of nerve a much longer immer- 

 sion in sugar solution (in the cold) was necessary in 

 order to abolish irritabiHty completely. The minimal 

 concentration of Na salts for preserving irritability 

 proved to be about the same as in muscle; on nerve as 

 well as on muscle K salts have a characteristic paralyzing 

 action, which is also antagonized by Ca and Sr in the 

 presence of Na salts. 



^ Overton, loc, cit. (1904). 



