Following Ueda-Yasuda's procedure, the author observed changes on the portal blood circulation time, the blood pressure and the pulse rate of five normal men following a bath in radioactive hot spring water. Measurements were taken three
times: 30 minutes before the bath, immediately after the bath, and 30 minutes after the bath (the bath waS either 5 or 10 minutes in duration, and ranged in temperature from 41° to 43℃). Portal blood circulation time immediately after a 10 minute bath waS found to be significantly prolonged as compared with that taken 30 minutes before the bath. The changes in blood pressure and pulse rate observed after bathing were similar to those reported by other authors.