PHYSIOLOGY OF GUSTATION 157 



such contrasts exist as extensively as was believed by the 

 older workers. It is a common opinion that after a sweet 

 drink a sour taste is more intense, but Oehrwall (1891) 

 was unable to confirm this experimentally nor could he 

 show that bitter increased the sensibik'ty to sweet. 

 Haycraft (1900) noted that when one border of the tongue 

 is rubbed with salt, the other border becomes hypersensi- 

 tive to sugar, but such a contrast is clearly not peripheral 

 but central in origin, and possibly other contrasts may 

 be thus explained. 



15. Taste Compensations and Mixtures. Mixtures 

 of sapid solutions do not as a rule give rise to tastes other 

 than those of their components. Lemonade has both the 

 sweet taste of the sugar and the sour taste of the citric 

 acid it contains. Sugar adds a pleasant element to cof- 

 fee, but does not destroy its bitter taste. In ordinary 

 food the flavor is the mixture of true tastes and odors 

 accompanied by the multitude of other buccal sensitivities 

 due to the variety of substances in the mouth and accep- 

 ted in a rather unanalyzed form by the central apparatus. 

 Yet in all this complexity the elements remain essentially 

 distinct. Competition rather than compensation seems 

 to be the rule. Kiesow ( 1894-1896 ) , however, has claimed 

 that a very weak solution of sugar and salt gives a taste 

 that is neither sweet nor saline but distinctly flat, and 

 Kremer (1918) has recently shown that a solution of 

 sodium chloride too weak to stimulate the saline taste 

 will, nevertheless, considerably increase the sweetness of 

 a cane-sugar solution. Quinine hydrochloride on the 

 other hand will, according to Kremer, reduce sweetness. 

 These instances may be evidence of gustatory compensa- 

 tion, but it seems much more probable, as was indicated 



