158 SMELL, TASTE, ALLIED SENSES 



in a preceding section, that they result from a sensitizing 

 or a desensitizing of the sweet receptors by the sodium 

 chloride or the quinine, for it is extremely doubtful, as 

 Oehrwall (1891) has stated, whether true gustatory com- 

 pensation ever occurs. Ionic antagonism such as Crozier 

 (1915) has discovered in the reaction of the frog's foot to 

 salt solution has thus far not been identified in taste. 



16. The Gustatory Senses. When a general survey 

 of the so-called sense of taste is made, the most striking 

 feature that appears is the remarkable independence of 

 the four categories, sour, saline, bitter, and sweet. These 

 are excited by groups of different stimuli, they give re- 

 markable evidence of having separate receptors, they are 

 differently acted upon by various drugs, and they show 

 numerous other peculiarities that are interpretable only 

 from the standpoint of organic separateness. So im- 

 pressed was Oehrwall (1891, 1901) with these peculiari- 

 ties that he declared them to be in all essentials four 

 separate senses, a declaration entirely in accord with the 

 component theory as applied to taste. Although this 

 view has a certain radical element in it and has not been 

 favorably received by such workers as Kiesow, Nagel, 

 Luciani, and Henning, who have declared for the unitary 

 nature of taste, it is difficult to say why it should not pre- 

 vail. It has been urged that gustatory compensation is 

 inconsistent with Oehrwall 's hypothesis and possibly this 

 may be true. But gustatory compensation is so uncer- 

 tain a phenomenon that when compared with the sub- 

 stantial body of evidence in favor of the hypothesis, this 

 objection lacks force. Henning (1916) has declared that 

 the tastes of different substances, members of one cate- 

 gory, are not necessarily alike ; thus the saline tastes of 



