PHYSIOLOGY OF GUSTATION 145 



in the following table in which the resolution of a number 

 of sweet compounds into glucophores and auxoglucs 

 is indicated. 



Table VII. 



A table of sweet organic compounds (aliphatic series) showing the 

 constitution of the compound and its resolution into a glucophore and an 

 auxogluc, from Oertly and Myers (1919). 



Glycine CH 2 NH 2 -COOH -CHNH 2 -COOH H- 



Ethyl nitrate C,H 6 ONO 2 -CH,ONO 2 CH 3 - 



Notwithstanding the elaborate attempts of Cohn and 

 of Oertly and Myers to elucidate the chemoreception of 

 sweet substances, the subject must be admitted to be one 

 that is far from settled. What may be said with cer- 

 tainty is that the sweet taste, like the bitter taste, is ex- 

 cited both by ions and by organic molecules the details 

 of whose activity, however, are by no means fully 

 worked out. 



8. Inadequate Stimuli. Taste is somewhat remark- 

 able for its paucity of inadequate stimuli. Although the 

 tongue is very sensitive to temperature differences, these 

 changes do not seem to excite the gustatory receptors. 

 It is questionable whether mechanical stimulation, such 

 as tapping the tongue as practised by the older physiolo- 

 gists, will call forth sensations of taste. The only really 

 effective form of inadequate stimulus for the gustatory 

 organs seems to be the electric current. As early as 

 1752 Sulzer noted the peculiar sensations when two dif- 

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