ELECTROPHYSIOLOGICAL STUDIES 

 DISCUSSION 



201 



We have only been able to record the electrical response from the whole 

 nerve trunk of the tympanic part of the chorda tympani of man. All our 

 attempts to split the nerve into fine strands have failed. We believe that 



0. 5M NaCl 



r TTii ii 



I II I I i 



«>■* 



0. 5% Acetic acid 



mm 



^ 



I i n II I l| 



0. OiM Quinine 



i*^4t«>-x 



IMi>4aiNMaM4NHH^ 



0. 5M Sucrose 



7M Ethanol 



Ii . Illli il II III 



i|i|i|i|i H tl M lilii)iil H lti # l H i(|i 



i iii O ii(iiiiiiiiii>i<li M iii i iii w iii<<iiiili>iii|ii i iii H ^ 



Fig. 10. Records from a fine strand of the dog's chorda tympani which 

 responded massively to sucrose but not to acid, salt or quinine. Note the 

 much stronger response to alcohol from this preparation compared to the 

 response to alcohol of the nerve strand recorded in Fig. 9. Time in seconds. 



U^ 



0.2 0.3 0.5 0.7 1 1.4 2 3 5 7 



B 



I I I ■ I 



0.2 0.3 0.5 0.7 1 1.4 2 3 5 7 



C 



0.2 0.3 0.5 0.7 1 1.4 2 3 5 7 



Fig. 11. Histograms showing the distribution of 13 subjects according to their 



threshold sensation of A sweet and B bitter. C shows the distribution of 



thresholds for the discrimination of alcohol solutions against water. 



this is mainly due to the physical properties of the chorda tympani in the 

 middle ear. It seems as if peripheral nerves lose a lot of their connective 



