According to P. N. Arata and F. Canzoneri1) the genuine Winter's bark of Drimys Winteri, Forst (family Magnoliaceae) contains 0,64 p. c. of a dextrogyrate volatile oil. In the main it consists of "winterene", a hydrocarbon boiling between 260 and 265°. According to the opinion of the investigators this is a triterpene. The boiling point, however, would indicate a sesquiterpene.