in THE SENSE OF TASTE 155 



heat. He also found that all the papillae investigated, including 

 the non-gustatory, were sensitive to tactile and thermal stimuli. 



Goldscheider and Schmidt also tested the papillae with solu- 

 tions of quinine and sugar mixed; they sometimes obtained a 

 sweet taste only from one papilla and bitter only on another. 



Kiesow's researches on the same subject were both a control 

 and a continuation of those of Oehrwall. An important differ- 

 ence between the methods of the two observers is that Oehrwall's 

 subjects were aware of the nature of the substance employed, 

 while Kiesow kept them in ignorance. The substances used were 

 solutions of sodium chloride (which Oehrwall gave up), sugar, 

 hydrochloric acid, and sulphate of quinine. The hydrochloric 

 acid was in 0'2 per cent solution, the others in almost saturated 

 solutions. 



The results practically agree with those of Oehrwall, and show 

 that the greater part of the papillae investigated do present 

 marked functional differences. 



Of 39 papillae examined, 4 gave no reaction to any of the 

 four substances. The other 35 (excluding doubtful reactions) 

 gave the following results : 



18 reacted to salt. 3 to salt exclusively. 



26 reacted to sweet. 7 to sweet exclusively. 



18 reacted to acid. 3 to acid exclusively. 



13 reacted to bitter. to bitter exclusively. 



This table shows that of the 35 taste papillae 



9 did not react to sweet. 

 17 salt. 



17 acid. 



22 bitter. 



This confirms the fact already brought out with another 

 method by Kiesow and Hiinig, that at the tip of the tongue sensi- 

 bility is maximal to sweet and minimal to bitter, the reverse of 

 what is observed at the base of the tongue. 



Kiesow further noted the interesting fact that within the 

 small space of a single fungiform papilla four senses may be 

 represented taste, touch, pain, and temperature ; the sense of 

 taste and the thermal sense can, moreover, be present in different 

 qualities of sensation, as sweet, acid, warm, cold. 



Kiesow also observed effects of peripheral fatigue which 

 Oehrwall neglected. And lastly, he found that in dealing with 

 these minute gustatory surfaces it was often difficult to distinguish 

 between the salt and the acid tastes, as he had previously noted 

 in his experiments upon children. 



These results of the effects of isolated excitation of separate 

 gustatory papillae seem to afford direct evidence that the different 

 qualities of tastes are based on a specific differentiation of proto- 



