144 SMELL. TASTE, ALLIED SENSES 



when acidic or basic substitutes are introduced into its 

 benzene nucleus. The introduction into a sweet molecule 

 of any considerable radical, especially an aromatic 

 one, is very likely to be followed by a change from 

 sweet to bitter. 



Cohn (1914) made an elaborate comparison of the 

 constitution of the sweet substances, as he did that of 

 the bitter compounds, and came to the conclusion that 

 these substances like the bitter ones contained particular 

 groups of atoms that determined their taste and that he 

 designated as glucogenes. Thus among alcohols one hy- 

 droxyl is accompanied with slight sweetness and four 

 or five with intense sweetness. But notwithstanding 

 the extent of Cohn's comparisons, Oertly and Myers 

 (1919) found his generalizations inadequate, and pro- 

 posed in place of his hypothesis one in which two groups 

 were assumed to be present in every sweet molecule. Fol- 

 lowing by analogy the terminology used for dyes, one of 

 these groups was called a glucophore and the other an 

 auxogluc. By a close comparison of the sugars, amino 

 acids, and halogen derivatives of the hydrocarbons, they 

 believed they could identify at least six glucophores and 

 nine auxoglucs. The glucophores are (1) CHoOH-CHOH-, 

 (2) -CO-CHOH-(H), (3) CO^H-CHNH,-, (4) -CH^ONO^, 



(5) Cgp-, and (6)C^3-x.QH2-y_ Tjie auxoglucs are (1) 



H-, (2) CH3-, (3) CH3GH2-' (4) CH3-CH.-CH,-, (5) 

 (CH3)2CH-, (6) CH2OH-, (7) CH3CHOH-, (8) CH.OH- 

 CH2-, and (9) radicals C„H2„,iO„ of nonnal polyhe- 

 dric alcohols. 



An illustration of the way in which Oertly and Myers' 

 theory may be made to apply to sweet substances is given 



