THE ACTION OF SOLUTIONS ON THE SENSE OF TASTE. 1 



Introduction. 



In order to be capable of affecting the sense of taste a sub- 

 stance must be soluble to a certain extent in the saliva, which 

 is, in most cases at least, the same as saying that it must be solu- 

 ble in water. Substances that are practically insoluble can 

 when introduced into the mouth produce only sensations of tem- 

 perature and of touch. The fact that a substance is soluble in 

 water is not of itself sufficient, however, to enable it to cause 

 sensations of taste, for there are many substances that are quite 

 soluble in water and yet their solutions possess very little or no 

 taste. It is evident that the effect of a solution on the sense of 

 taste depends upon the concentration of the solution, the chem- 

 ical nature of the dissolved substances, and the conditions in 

 which the latter exist in the solution. 



Investigations on the subject of solutions have been vigorously 

 pushed during the last ten years by workers in the field of physi- 

 cal chemistry, and as a result of their labors we have today a 

 far better understanding of the condition in which a substance 

 exists when dissolved than ever before. Indeed, van't Hoff's 1 

 theory of solutions and Arrhenius' 2 theory of electrolytic dis- 

 sociation have practically solved the mystery that has hereto- 

 fore engrossed the whole subject of solutions. 



Since substances must be dissolved in order to be tasted, and 

 since the taste of a solution depends upon the nature of the dis- 

 solved substance and its molecular condition when in solution, 



'Read before the Wisconsin Academy of Sciences, Arts, and Letters at its 

 meeting at Milwaukee, December, 1897. 

 2 Zeitschr. f. physik. Cbem. 1, 481, 1887. 

 3 Ibidem, 1, 631, 1887. 



