I. Foreword Quantitative, serial surveys of the uropepsin output in the urine of the bathing patients in Kusatsu Spring have led us to a knowledge that there exists in the gastric secretion relationship between its activation caused by consecutive-bathing stress and its suppresion brought about as an effect of hot bathing. II. Experiment (1) Procedure: West's rennett method was employed in our investigation, using a buffer of sodium acetate with a pH of 5.3, and the results are given in terms of mg. value of the concentrated pepsin manufactured by the Mikuni Chemical Firm. (2) Nature of Spring Water and Way of Bathing: The hot springs at Kusatsu are of strongly acid sulfated water and of a high temperature of ca. 44°C. The subjects were ordered to take a bath three times a clay, in the morning, afternoon, and evening. (3) Subjects: The test subjects were chosen chiefly from among those patients, who were already almost restored to normal. III. The Fluctuation seen during Consecutive Daily Bathing (1) Uropepsin Output: See Chart 2. Six patients were examined. The uropepsin output gradually increased with bathing and reached its maximum in about 10 days, four times higher than at the start of the experiment, then followed a gradual decrease until it returned to its original value. (2) Diurnal Change: The urine for test was collected in such a way that the first portion was that of urination during the night from 10 p. m. to 7 a. m.. Then, the material was collected every three hours until 10 p. m., thus six separate urine samples were obtained. For control, similar test was conducted again in the same subjects without taking a bath. Comparative study with each corresponding materials showed clear decrease of uropepsin quantity in the 2nd, 4th, and 6th portion of the urine, which coincided with the bathing, as seen on chart 3. (3) Diurnal and Daily Fluctuation: Daily difference in uropepsin excretion and difference within a day were checked. Chart 4 shows the relationship between those two kinds of fluctuation in one case. Even at the height of uropepsin output, there was still noted a certain decrease in the portion of the urine, when the subject took a bath. IV. Discussion Stress increases uropepsin output with the stimulation of pituito-cortico-gastric system, as said by Gray et al. There are some reports, proved at our institute, that bath treatment brings a stimulation effect upon the adrenal cortical function, the climax being reached about 10 days after the start of treatment. Our findings agree with them. On the other hand, there are some reports that high temparature bathing brings supression of gastric secretion, which has been proved with Katsch-Kalks' method in our institute, too. Our study of diurnal fluctuation coincides with it. Serial quantitative determinations of uropepsin output enabled the study of these two simultaneously by and contradictorily working reactions, because temporary decrease of uropepsin excretion was observed even at the climax of consecutive bath effect, However, an increase of uropepsin output was noted in the total amount. V. Conclusion The action of consecutive bath treatment was studied through the quantitative determination of uropepsin output and it was proved that hot bath treament produces two different effects, that is, consecutive bath treatment having a stimulating effect on the adrenal cortex and hot bath a suppresive effect on gastric secretion.