1. Postural reactions to caloric stimulation of the vestibular organ were measured in a group of 20 chronic schizophrenic patients and in a group of 20 normal persons. The blind-folded subjects were instructed to mark time in place, and the reaction was measured by the degree of rotation about the vertical axis of the body.2. The test was first administered without vestibular stimulation in order to determine the amount and direction of the rotation, which is an expression of the dominance of one side of the body. Such "basal trends," which were present in all subjects, were taken into account when calculating the amount of vestibular reaction.3. The mean total vestibular reaction measured in degrees of rotation was, in the patients, less than one-half that of the normal subjects. In spite of the great variability of the phenomenon studied, this difference is statistically highly significant.4. The total duration of the reaction, as well as the degree of rotation per time unit was found to be significantly less in the patients than in the normal controls. That is, the reaction of the patients was more fleeting and less intense than that of the normal controls.5. It is suggested that the difference found may be due either to the depressed activity of the nervous mechanisms involved or to a diminished muscle tonus of the schizophrenic patients.Abstract Teaser