H. Bungener (BzLZZ. SOC. chim., 1886, [ii], 45, 487) confirmed the observation of Lermer (Zoc. cit.) respecting the occurrence of a crystalline acid, insoluble in water, which rapidly became yellow and resinous on exposure t o the air. H e designated the substance "lupulic acid," stating it to melt a t 92-93*, and to agree in composition with the formula C50H7008. It was furthermore considered that it is the resinous oxidation product of this acid which imparts bitterness t o a decoction of hops, and that this resinous product exists in hops together with the acid from which it is readily formed. Bungener and Fries (Zeitsch. ges. Brauw., 1885, 8, 267) have stated that hops contain asparagine, but although the method of separation was given, no analysis or other evidence of the identity of the substance appears to have been recorded. Issleib (Arch. Pharm., 1880, 13, 345), from the results of a somewhat extended investigation, has concluded that hops contain a peculiar bitter substance, " hop-bitter," of the composition C29H4,0,0. This, when treated with dilute sulphuric acid, is said to be converted into a resinous product, " lupuliretin," C10H1604, and a crystalline, bitter substance, " lupulinic acid,," C,,H8201,, which is insoluble in water, the change being represented by the following equation : 2C29H46010 + 3H20 =C10H1604 f C48H82019* The same author, furthermore, assigns to hop-resin the formula Cl0HI4O3, and assumes that by the simple addition of a molecule of water it is converted into " lupuliretin," C,,H160,. On the other hand, hop-resin, C10H1403, is considered t o be produced by the oxidation of the essential oil of hops, the latter being given the formula CloH180, and the change represented as follows : C1oH180 + 2 0 , = C,,Hl40, + 2H2O. Inasmuch as it is well known, however, that both hop-resin and the essential oil of hops are very complex products, the latter consisting largely of a sesquiterpene, Cl5HZ4, the fallacy of the above conclusions is apparent.