PHYSIOLOGICAL STUDIES OF GUSTATORY MECHANISMS 251 



The test solutions and the wash (distilled water or Ringer's solution) were 

 maintained at 32-36°C by immersion in a water bath in order to minimize 

 stimulation of thermoreceptors whose axons run in the chorda tympani 

 nerves (Dodt and Zotterman, 1952). 



The neural responses recorded from the chorda tympani and lingual 

 branches of the glossopharyngeal nerves following the application of the 

 test solutions are illustrated in Figs. 1 1 to 16. The gain of the integrator was 



GOAT GLOSSOPHARYNGEAL NERVE 



I I 



I I I I 



1 SEC. 



Fig. 14. Records from the whole Hngual branch of the glossopharyngeal nerve 

 of a goat. Recording procedure same as in Fig. 1 1 except the region of the 

 tongue where the vallate papillae are located was stroked with a wooden probe 

 twice before and twice or more during the application of the test solutions. 

 Distilled water was applied to the tongue about 10 sec before each record was 

 made. A, Distilled water. B, 0.5 m sodium chloride. C, 0.46 m sucrose. D, 

 0.02 M quinine hydrochloride. E, 0.2 m acetic acid (Kitchell and Bell, 



unpublished). 



adjusted on the basis of the response obtained in the chorda tympani nerve 

 following the application of the 0.5 m sodium chloride solution. Once a 

 series was started neither the preamplifier nor the integrator settings were 

 adjusted until the series was completed. In most of the animals studied, 

 the integrated response following the appHcation of 0.2 m acetic acid to the 

 tongue was of greater magnitude than the integrated responses elicited by 



