224 



JIHEI KONISHl AND YNGVE ZOTTERMAN 



repellent, could not be distinguished from other inactive amino acids in its 

 gustatory stimulating effect. Urea, creatinine, NH3, lactic acid, citric 

 acid, cholesterine, bradykinin, kallikrein and parotine, salivary gland hor- 

 mone, all displayed a weak effect in low concentrations (Fig. 8). 



Fig. 8. Electrical responses from the carp's palatine nerve to the application 

 of the solutions of different substances which are contained in the human saliva 

 to the palatal organ. A, human saliva; B, 0.2% mixed solution of salts 

 (0.0836 g % KCl, 0.0468 g % K0HPO4, 0.0372 g % Na^HPOi, 0.0203 g % 

 CaHP04 and 0.00074 g % MgHPOi) ; C, 0.2% cattle submaxillary niucin in 

 0.2% salt sol. ; D, 0.2% submaxillary mucin and 0.004% KCNS in 0.2% 

 salt sol. ; E, human saliva ; F, boiled and filtrated saliva ; G, 3 mg % glycine ; 

 H, 3 mg % glutamic acid ; 1. 3 mg % serine ; J, mixed solution of vitamins ; 

 K, 0.1 M glucose ; L, 10 mg % lactic acid ; M, 10 mg % creatinine ; N, 

 cholesterine ; O, 30 mg % urea ; P, 20 B.U. % kallikrein ; Q, 5 mg % parotine. 



Time in seconds. 



In order to find the active substance, experiments were performed from 

 another direction. Saliva was fractionated by organic solvents. To the 

 saliva was added an excess of 99.5 per cent ethanol, and the precipitates of 



