The direct formation of alcohol from sugar by the action of alkalis appears first to have been observed by Duclaux [1886], who exposed a solution of glucose and caustic potash to sunlight and obtained both alcohol and carbon dioxide. As much as 2·6 per cent. of the sugar was converted into alcohol in a similar experiment made by Buchner and Meisenheimer [1904]. When the weaker alkalis, lime water or baryta water, were employed instead of caustic potash, however, no alcohol was formed, but 50 per cent. of the sugar was converted into inactive lactic acid [Duclaux, 1893, 1896]. Duclaux therefore regarded the alcohol and carbon dioxide as secondary products of the action of a comparatively strong alkali on preformed lactic acid. Ethyl alcohol can, in fact, be produced from lactic acid both by the action of bacteria [Fitz, 1880] and of moulds [Mazé, 1902], and also by chemical means. Thus Duclaux [1886] found that calcium lactate solution exposed to sunlight underwent decomposition, yielding alcohol and calcium carbonate and acetate, whilst Hanriot [1885, 1886], by heating calcium lactate with slaked lime obtained a considerable quantity of a liquid which he regarded as ethyl alcohol, but which was shown by Buchner and Meisenheimer [1905] to be a mixture of ethyl alcohol with isopropyl alcohol. It appears, therefore, that inactive lactic acid can be quite readily obtained in large proportion from the sugars by the action of alkalis, whilst alcohol can only be prepared in comparatively small amount and probably only as a secondary product of the decomposition of lactic acid. The study of the action of alkalis on sugar has, however, yielded still further information as regards the mechanism of the reaction by which lactic acid is formed. A considerable body of evidence has accumulated, tending to show that some intermediate product of the nature of an aldehyde or ketone containing three carbon atoms is first formed. Thus Pinkus [1898] and subsequently Nef [1904, 1907], by acting on glucose with alkali in presence of phenylhydrazine obtained the osazone of methylglyoxal, CH{3}·CO·CHO. This osazone may be formed either from methylglyoxal itself, from acetol, CH{3}·CO·CH{2}·OH, or from lactic aldehyde, CH{3}·CH(OH)·CHO [Wohl, 1908]. Methylglyoxal itself may also be regarded as a secondary [p099] product derived from glyceraldehyde, CH{2}(OH)·CH(OH)·CHO, or dihydroxyacetone, CH{2}(OH)·CO·CH{2}(OH), by a process of intramolecular dehydration, so that the osazone might also be derived indirectly from either of these compounds [see also Neuberg and Oertel, 1913]. Methylglyoxal itself readily passes into lactic acid when it is treated with alkalis, a molecule of water being taken up:-- CH{3}·CO·CHO + H{2}O = CH{3}·CH(OH)·COOH. Further evidence in the same direction is afforded by the interesting discovery of Windaus and Knoop [1905], that glucose is converted by ammonia in presence of zinc hydroxide into methyliminoazole,