“ Alkali fusion of eugenol gives protocatechuic acid. The amount of eugenol in oil of cloves can be estimated by acetylation, in presence of pyridine (A. Verley and Fr. Baelsing, Ber., 1901, 34, p. 3359) . Chavibetol, an isomer of eugenol, occurs in the ethereal oil obtained from Piper betle. ”