402 THE OUTGO OF ENEKGY 



threshold value. Einse the mouth, and then 

 swallow a much larger portion of the solution. 



The taste will be perceived more strongly, the 

 larger the area stimulated. 



Electrical Stimulation. 1. Connect two small 

 zinc electrodes through a simple key to a battery 

 of four dry cells. Apply one electrode to an in- 

 different region, the other to the tongue. Close 

 the key. 



Note the sour taste at the positive pole and 

 the alkaline taste at the negative. 



