Abstract
The concentration of vitamin B_6 and pyridoxic acid in the rat urine began to increase immediately after a sound stimulation of 3000 cps, 115 phon for 8 hours per day, had been given and reached their maximum values in about a week, and then decreased below the normal values, reaching their minimum points in about 2 weeks, followed by returning to their normal concentrations. The most typical change was observed in the case of pyridoxic acid. Similar changes were observed in the vitamin B_6 and pyridoxic acid contents of liver, kidney, brain and blood. However, in the latter case, such a tendency was most remarkable in the change of pyridoxal.
