1. The effect of temperature change on the chorda tympani response of the cat has been investigated, by carrying out the stimulation of the tongue by NaCl, KCl, HCl and quinine at varying temperatures. 2. The greatest response magnitude was obtained at 30°C for NaCl, HCl and quinine, while the response to KCl showed a maximum magnitude at 35°C. 3. The Q10 values for NaCl and KCl stimulation were small compared with those for HCl and quinine. A possible significance of this result for the mechanism in receptor-substance reaction was discussed. 4. The thermal responses in both the chorda tympani and the lingual nerve to temperature change of the tongue were described.