152 SMELL, TASTE, ALLIED SENSES 



tested was near the tip of the tongue is probably the 

 occasion of the absence in the records of any papillae 

 stimulated exclusively by quinine, for this region is one 

 in which the bitter taste is least developed. Kiesow also 

 observed that the papillae presented a great variety of 

 combinations in taste ; some were open to stimulation by 

 two of the four reagents used, others by three and still 

 others by all four. It is known that each gustatory 

 papilla carries a number of taste-buds but whether in 

 those papillae that are open to stimulation by two or more 

 sapid solutions there is a corresponding number of kinds 

 of buds, one for acid, another for salt reception and so 

 forth, cannot be stated, for it is possible that this dif- 

 ferentiation may reach to the gustatory cells of each 

 bud. What can be affirmed, however, is that in those 

 papilte that respond exclusively to one taste all taste- 

 buds with their contained cells must be so constituted as 

 to be open to stimulation by one class of sapid substances 

 and to be closed to all other classes. Thus in a papilla 

 that is stimulated exclusively by acid the protoplasm of 

 the receptive cells in all its taste-buds must be organized 

 to receive acid stimuli and not to react to those for the 

 saline, bitter and sweet tastes. This conclusion amounts 

 to a very complete confirmation of Miiller's theory of the 

 specific energy of sensory nerves as it is interpreted in 

 modem physiology and to the component theory as ap- 

 plied to taste. 



^ 10. Action of Drugs on Taste. Certain drugs have 

 the remarkable property of temporarily diminishing or 

 even obliterating taste. Edgeworth discovered that af- 

 ter a person had masticated the leaves of the Indian 

 asclepiad Gymnema sylvestre, he was unable to taste 



