PHYSIOLOGICAL STUDIES OF GUSTATORY MECHANISMS 247 



care must be taken not to remove or damage small fasciculi lying near the 

 surface of the nerve. After the nerve is properly prepared a " pool " is con- 

 structed from the skin and surrounding tissues. Mineral oil is placed in the 

 pool. The temperature of the mineral oil is maintained at 35 to 37°C. The 

 chorda tympani nerve is placed across silver wire electrodes connected to 



CAIF CHORDA TYMPANI NfRVI 



m 



^ 



1 SEC. 



Fig. 1 1 . Records from the whole chorda tympani of a calf. In each are recorded 

 from the top to bottom : The integrated response, the direct response and a 

 signal indicating that the stopcock of the dispensing burette is open. In the 

 last two records a 5 sec segment has been deleted. In each instance the first black 

 signal line indicates the application of distilled water and the second indicates the 

 application of the following solutions. A, 0.5 m sodium chloride. B, 0.46 m 

 sucrose. C, 0.02 m quinine hydrochloride. D, 0.2 m acetic acid (Bell and 

 Kitchell, unpublished). 



a Grass P5 low level a.c. preamplifier. The output of the amplifier is dis- 

 played on one beam of a dual-beam Dumont oscilloscope for photographic 

 recording. An integrator is connected in parallel to the output of the 

 amplifier. The output of the integrator is displayed on the second beam of 

 the oscilloscope. In certain of the experiments the output of the Grass P5 

 preamphfier was connected to a Grass 5P3 preamplifier and integrator. 

 The output of the integrator was recorded by the polygraph. 



The difficulties encountered in quantitating and interpreting activity in 

 nerves from the tongue has been discussed previously (Zotterman, 1935 ; 



