Abstract
Solutions of sodium chloride, sucrose, tartaric acid, and quinine sulphate were each presented in successive ascending series, both with and without interstimulus tapwater rinses, to six subjects. A tendency for detection and recognition thresholds to be raised on successive ascending series was noted for all stimuli. The effects were explained in terms of adaptation to stimulus residuals. When water rinses were taken between tastings, significantly lower thresholds were noted for sodium chloride and glucose. Although this trend did occur for tartaric acid and quinine sulphate, it was not significant. The literature was examined and seen to show similar trends.