PHYSIOLOGY OF GUSTATION 139 



faces of gustatory cells at different rates, their uniform 

 sour taste may then be ascribed to their common dissocia- 

 tion product, the hydrogen ion. How this is accomplished 

 is, according to Crozier, the second problem in gustation. 

 That the sour taste is in some way dependent upon hydro- 

 gen ions seems true beyond reasonable doubt. How these 

 ions become effective is still a problem. 



5. The Saline Taste. The saline taste is typified by 

 that of common salt. Sodium chloride, however, is not 

 the only substance that possesses this taste, for there is 

 a whole range of compounds that have the same property. 

 The chlorides of potassium, lithium, ammonium, and mag- 

 nesium, the hydro chlorides of monomethylamine and of 

 diethylamine, the bromides and iodides of sodium and of 

 potassium as well as their sulphates and nitrates are 

 all more or less saline in taste. 



Aqueous solutions of most of these salts show a high 

 degree of dissociation so that, beside undissociated mole- 

 cules, cations and anions are present in these solutions 

 as possible stimuli for the saline taste. Hober and Kiesow 

 (1898) have worked on this question and have declared 

 in favor of ions as the stimulating agents in contrast with 

 undissociated molecules. Kahlenberg (1898) arrived at 

 the same conclusion. He found that a solution of sodium 

 chloride, 0.02 molar, was scarcely to be distinguished by 

 taste from pure water. At 0.04 molar it was a trifle 

 saline. Corresponding solutions of sodium acetate were 

 almost tasteless and certainly not in the least saline. 

 Hence it is evident that the salty taste of sodium chloride 

 is due to chlorine ions and not to sodium ions. This con- 

 clusion is supported by the fact that 0.04 molar solutions 

 of potassium chloride and of lithium chloride are also 



