Having thus shown the presence of butyric, acetic, and formic acids in the drench, we proceeded to ascertain the quantities formed in a normal fermentation of bran without skins. For this purpose a drench was made in a clean vessel with 10 litres of distilled water and 200 grm. of bran mashed at a temperature of 38° C., and, after cooling to 33°, inoculated with bacteria from an actual drench which was fermenting vigorously; this was kept in the drench house so that the fermentation and general conditions might be exactly similar. In 48 hours all gases had ceased to be evolved, and the true fermentation was at an end. The liquid had an acid, not unpleasant smell, and was acid to litmus paper. The bran was strained off through muslin, washed with a little water, and well squeezed; the liquid measured 10 litres. Three litres of this were taken for the separation and estimation of the volatile acids, the remainder being set aside for examination and estimation of the non-volatile acids, etc. Two of the three litres were placed in a distilling flask with 5 grm. of pure CaCO_{3}, and distilled down to one litre. The distillate was _alkaline_ to litmus, and had a peculiar fishy smell; the remaining litre of drench was added, and the liquid taken down until the distillate ceased to be alkaline and only bad a faint smell. The alkaline distillate gave a yellow precipitate with Nessler’s solution, as well as the following reactions:-- AgNO_{3} A faint brown precipitate. HgCl_{2} A yellowish-white curdy precipitate. PbA A brownish-white precipitate. CuSO_{4} A dirty blue precipitate, which changed to a brownish turbidity on boiling. HCl was added to the distillate in slight excess and the liquid evaporated to a small bulk; to a portion chloroform and alcoholic potash were added, and the liquid heated; no smell of isocyanides was given off; the body is, therefore, not a primary amine. Phosphomolybdic acid gives no precipitate, therefore the body is not an alkaloid. From the above tests and its characteristic smell, we conclude that the body is _trimethylamine_. The platinum salt was formed by evaporating the above concentrated solution of trimethylammonium hydrochloride with excess of platinum chloride, a precipitate of the platinum salt insoluble in alcohol being formed. There was not, however, a sufficient quantity from the three litres to ascertain the molecular weight. Proceeding with the estimation of the volatile acids, 100 c.c. N HCl being required to completely neutralise the CaCO_{3} used, 50 c.c. were first added and the distillation continued; the distillate was only very faintly acid. Four fractions were now distilled off, using respectively 10, 10, 10, and 20 c.c. N HCl.[165] [165] Method recommended to us by Dr. Frankland. _Vide_ Jour. Chem. Soc. Trans. 59, p. 94. Appendix II. Determ. of Vol. Acids by dist. with HCl.