IN the second issue of the Zeitschrift fur Physio-logische Chemie for 1932, Prof. Windaus and his co-workers announce the isolation of the anti-neuritic vitamin B1 in what appears to be the pure state. In 1926, Jansen and Donath reported the preparation from rice bran of a crystalline substance having the formula C6H10ON2, which was believed to be the vitamin, but subsequent work, notably that of Jansen, Kinnersley, Peters, and Reader, in 1930, showed that the substance was not pure. In 1929, Windaus took up the preparation of vitamin B1 from yeast, and in the initial stages of purification lie followed well-known lines. From the neutralised raw extract he has recently prepared the gold salt, decomposed this with hydrogen sulphide, and from the filtrate isolated the picrolonate, which is dimorphous. Analysis of the picrolonate gave the surprising result that the vitamin contains sulphur as well as nitrogen: its formula is probably C12H17N3OS. The hydrochloride was prepared; its absorption spectrum gave a maximum at 250–260uu,and its potency, determined on pigeons, was 1.4-3.3, as against 97 found by Jansen and others for the substance isolated by the original method of Jansen and Donath. Prof. Windaus states his belief that he has now isolated the pure vitamin.