For one year between 1950 and 1951, specific weight of tissue powder of rhizomes without roots of Scopolia japonica Maxim., growing wild in a certain area, was measured by Koketsu's powder method and a marked seasonal variation was found to exist (Table I and Fig. 1). The cause of this variation was found to be due to the amount of starch accumulated (Table I and Fig. 2). Consequently, it was proposed that tne customary representation of its component content by the weight percentage was of little physiological significance. Therefore, the determined values of total alkaloid and total nitrogen were shown by the volume percentage calculated from specific weight of tissue powder (Table I and Fig. 3). From these values, a large seasonal variation of alkaloidal content could not be detected.