To determine the acids of the acetic group, Kohnstein and Simand proceed as follows:--100 _c.c._ of the liquor are distilled, in a flask or retort with a good condenser, to about 30 _c.c._, allowed to cool a little, made up again to 100 _c.c._, and again distilled; and this is repeated till about 300 _c.c._ have passed over. The distillate is then made up to 300 _c.c._, well mixed by shaking, and the acid is determined with standard soda. Methyl orange and sodic carbonate is not so suitable for this titration, as caustic soda and litmus, since methyl orange is not very sensitive to vegetable acids. If it be desired to ascertain what quantity of acids of the acetic group exist in combination with lime and other bases in the liquor, small excess of sulphuric acid may be added to the residue in the retort, and the distillation repeated, when the organic salts will be decomposed and the volatile acids come over. To determine the total free organic acids, Kohnstein and Simand shake about 80 _c.c._ of the liquor with 3-4 _grm._ of freshly ignited magnesia, quite free from carbonate and from lime, and allow to stand for some hours with frequent vigorous shaking, till the liquor, which at first is brown or dirty green, becomes almost colourless and gives no reaction of either acid or tannin. The mixture is then filtered, and the tannin and colouring matter are retained on the filter in combination with magnesia, while the organic salts of magnesia, which are mostly soluble, pass through with the filtrate. 10-30 _c.c._ of the filtrate, according to the amount of acid present, is evaporated to dryness, and gently ignited so as not to decompose any magnesic sulphate present. The residue is moistened with water saturated with carbonic acid, to convert any magnesic oxide into carbonate, and then dried, in order to make the mass powdery, and easier to wash, It is next taken up with hot distilled water, filtered and well washed. Any sulphate which is present passes into the filtrate, while the carbonate, which corresponds to the organic salts present before ignition, remains on the filter, and after solution in hydrochloric acid, is estimated as magnesic pyrophosphate. To the hydrochloric solution is added excess of ammonia and sufficient ammonic chloride to redissolve the precipitate formed, and prevent the precipitation of the magnesia; the solution is heated and then ammonic oxalate solution, first dilute, and then concentrated, is added to precipitate any lime which may be derived from lime salts present in the liquor. After filtering out and washing the precipitate, 10-15 _c.c._ of 10 per cent. sodic phosphate solution is added, and the liquid is stirred with a glass rod without touching the sides of the beaker, and allowed to stand 12 hours. The crystalline precipitate is then rinsed on to a filter, and washed with a mixture of 1 of ammonia and 3 of water, till the washings no longer give any milkiness with silver nitrate.