Genetics of Sensory Thresholds: Variations within Single Individuals in Taste Sensitivity for PTC

Abstract

The ability of some persons and the inability of others to taste crystals of phenyl-thio-carba-mide and the taste acuteness for solutions'' of different concentrations are due to innate hereditary differences. A critical study of the methods used in determining these thresholds showed that at any one time a temp. range from 8 to 55[degree] C does not affect the threshold. An individual does not taste the substance in below-threshold dilutions even when large quantities are held in the mouth for several minutes. The threshold of individuals may vary from a factor of 2 to one of 256 during a day or from day to day. It was not possible to correlate these changes with routine daily habits. It is suggested that changing thresholds may be connected in some way to changing physiological states. Greater refinement in methods will be useless until such correlations are analyzed.