Abstract
Summary
Parotid gland secretion rate was measured in a group of 12 subjects selected as being relatively non-amenable to suggestion. Parotid fluid was obtained using a vacuum cup and collected in tubes graduated to 0.1 ml. Secretion rate was determined by measuring the volume secreted during a 10 minute stimulation interval. Solution concentrations were: citric acid—0.5, 1.0, 1.5, 2.0, 2.5, 3.0 g/100 ml; sucrose—5, 10, 15, 20, 30, 40 g/100 ml. After the subjects had experienced the gustatory sensations under control conditions (non-suggestion), and their secretion rate ascertained, they were asked to imagine various experimental (suggestion) conditions. It was observed that the parotid gland secretion rate was greater when the subjects received citric acid without suggestion than when citric acid was suggested to be sweet. The latter, in turn, was greater than the rate obtained when citric acid was suggested to be tasteless. The flow rate obtained when sucrose was suggested to be sour was greater than for sucrose without suggestion, while sucrose suggested to be tasteless evoked the lowest secretory rate in this triad.
Chi square analysis of the data indicated that the differences among secretion rates for each triad were statistically significant. However, when the variables were compared separately, using the sign test, it was observed that the differences between citric acid vs citric acid suggested to be sweet and sucrose vs sucrose suggested to be sour were not statistically significant.
The authors are indebted to David S. Calverley for his assistance in pretesting the subjects.
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