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An audiovisual stimulus was made contingent upon the rat’s licking at the water spout, thus making it analogous with a gustatory stimulus. When the audiovisual stimulus and the gustatory stimulus were paired with electric shock the avoidance reactions transferred to the audiovisual stimulus, but not the gustatory stimulus. Conversely, when both stimuli were paired with toxin or x-ray the avoidance reactions transferred to the gustatory stimulus, but not the audiovisual stimulus. Apparently stimuli are selected as cues dependent upon the nature of the subsequent reinforcer.

Beidler derived an equation relating the magnitude of neural response to a gustatory stimulus with the concentration of that stimulus. In the derivation, he assumed the amount of stimulating substance removed from the solution by the receptors was small enough not to change the stimulus concentration appreciably. An equation without this assumption is derived, and is evaluated in the light of existing data. The hypothesis for a dissociation reaction in taste inception under some circumstances is given support.

The concentrations of protein and protein-bound carbohydrates in human submaxillary saliva depended on salivary flow rate and not on the specific type of gustatory stimulus. “Unstimulated” saliva had the highest concentration of protein-bound carbohydrates. Low flow rates were associated with the lowest concentrations of protein and protein-bound carbohydrates, and as flow rate was increased, there was an accompanying increase in the concentrations of these substances. The concentrations of protein-bound carbohydrates were highly variable in “unstimulated” saliva. Stimulated saliva was relatively more predictable in composition. Protein concentration averaged 122 ± 76 (S.D.) mg%; however, the change in concentration from the lowest to the highest value recorded represented an increase of 1600%. Similarly, the concentration of protein-bound carbohydrates varied as much as 450% in the case of galactose. Average concentrations (μM) for protein-bound carbohydrates were: galactose, 395 ± 235; hexosamine, 290 ± 169; sialic acid, 151 ± 83; fucose, 160 ± 108. Secretors of blood group substances had concentrations of protein-bound carbohydrates higher than non-secretors, except for sialic acid concentration which was similar for the two groups. The sialic acid/fucose ratio for secretors was 0.64 ± 0.12 and did not vary with flow rate. The ratio for non-secretors was 1.40 ± 0.35 and rose with increasing flow rate.