THE OLFACTORY STIMULATING EFFECTIVENESS OF HOMOLOGOUS SERIES OF SUBSTANCES STUDIED IN THE FROG

Abstract

1. The stimulating effectiveness of homologous series of alcohols, acetates and ethers were studied in the olfactory epithelium of the frog by successive and single application methods. The results obtained by both methods were entirely coincident.The stimulating effectiveness of a saturated alcohol vapour increases following the increase of carbon number, but it decreases beyond C6. The stimulating effectiveness of a saturated acetate vapour increases gradually as the carbon number increases. But that of ether vapour has a maximum at C3, and it decreases as the carbon number increases.2. The stimulating effectiveness of alcohol vapour from the aqueous solution was studied at the concentration of 0.001M and 0.01M. The results were different from those obtained by OTTOSON.3. The stimulating effectiveness was studied in the homologous substances of equal thermodynamic activities. It was found that they are nearly the same when the value of the thermodynamic activity is 0.01, but that they become different when the value exceeds it. It was made clear that BRINK-POSTERNAK'S rule (1958) is only applicable in a small range of the values of the thermodynamic activity in the frog.4. The stimulating effectiveness of alcohols was studied on the equimolecular basis. The results were coincident with the calculated values of the thermodynamic activities of these alcohols except at C7 and C8. The mechanism of such a deviation was considered.5. The relation between the steric configuration of the odorous substance and the stimulating effectiveness was studied.6. There were found a peak and a break in the curve which shows the stimulating effectiveness of homologous alcohols. The origins of these discontinuities were discussed.