ROKITANSKY1AND SCHIFF,2in the 1840's, demonstrated clinically and experimentally a relationship between central nervous system abnormalities and gastric ulcer formation. In 1932, Cushing's3clinical findings confirming these earlier observations lent impetus to renewed interest in the evaluation of the responsible factors. One method of approach has been the assessment of the possible role of the autonomic centers in ulcerogenesis.4, 5Controversial results have been reported by investigators regarding hydrochloric acid production following hypothalamic stimulation.6,7Among the variable factors which may be responsible for the disparity in results are (1) the intensity of the stimulating current, (2) methods of collecting secretions, (3) short duration of experiments, and (4) the depth of anesthesia, resulting in varying thresholds to stimulation. In an attempt to clarify this problem, an experiment was designed to evaluate hydrochloric acid secretion following chronic hypothalamic stimulation at varying intervals in unanesthetized animals.