One hundred grams of uric acid (0.595 mole) and 4.5 l. of hot (70–85°) water are placed in a 12-l. round-bottomed flask equipped with a mechanical stirrer. The stirrer is started, and a solution of 80 g. (2 moles) (Note 1) of commercial sodium hydroxide in 120 cc. of water is added. Stirring is continued until the uric acid is in solution (Note 2), after which the solution is cooled by means of a stream of water directed against the flask. When the temperature has fallen to 25–30°, 50 g. (0.32 mole) (Note 3) of potassium permanganate is added all at once (Note 4) to the vigorously stirred solution. Stirring is continued for fifteen to twenty minutes (Note 5), and the mixture is filtered (Note 6) at once through a 19-cm. Büchner funnel. The first fraction of the filtrate contains a small amount of manganese dioxide. This fraction must be collected separately and returned to the funnel. As soon as the filtrate becomes clear it is collected in a 12-l. round-bottomed flask which contains 130 cc. (137 g., 2.2 moles) of glacial acetic acid. The filtrate is tested with litmus to be sure that it is acid, and evaporated to a volume of 1.5–2 l. on a steam bath under reduced pressure (20–30 mm.). The solution thus obtained is allowed to stand in a cool place overnight, and the allantoin which crystallizes is filtered on a 9-cm. Büchner funnel (Note 7). The allantoin is dissolved in 800–900 cc. of boiling water, treated with 5 g. of Norite, and filtered rapidly through a fluted filter paper in a steam funnel. The filtrate is allowed to stand in a cool place overnight (Note 8), and the white crystals of allantoin are separated by filtration with suction. The yield of product melting at 230–231° (Note 9) is 60–71 g. (64–75 per cent of the theoretical amount). If the filtrate from the purification liquors is concentrated to 100 cc., there is obtained an additional 3–5 g. of allantoin.