Starting from the presumption that bating and puering are, in the main, bacterial processes, more or less successful attempts had been made previous to those of Wood, Popp and Becker, to substitute other fermenting substances for dung; and probably these efforts failed in many cases, not so much because they were wrong in principle, as from want of knowledge of the necessary details, such as the use of proper ferments, and the provision of suitable culture-media. Guano, prepared horse-flesh, urine, yeast, and fermenting vegetables have all been tried. A solution of glucose or treacle of about 10 per cent., to which 3 per cent. of pasty dog-puer is added about a week before use, was tried many years since in a morocco-factory, at the suggestion of the writer, as at least a partial substitute for puer, and is still in use there. The mixture keeps for some time in an active state, and is added to the puer liquors in the same way and in approximately the same proportions as the dung paste. Similar in principle is the solid bate supplied by an American firm, in which glucose is mixed with a small amount of nitrogenous matter and phosphates, together with a lactic ferment, and which only requires dissolving in warm water some little time before use. Its results are good for some purposes, but rather resemble those of a drench than a bate. In a similar way, puer may be added to bran-drench liquors, and induces in them a fermentation which brings the skins down much lower than the ordinary drench. It is probable that a weak glucose solution, with traces of mineral constituents similar to Cohn’s solution (see L.I.L.B., p. 269) and “set” with sour milk, or fermenting drench-liquor, might in some cases be used with advantage for drenching, with a saving of cost. A writer in ‘Hide and Leather’ describes a bate in which two parts by weight of glucose are dissolved in about 25 parts of water, and fermented, for about three days, till a foam gathers on the top, with about one part of old bran drench-liquor, or 0·1 part of pressed yeast, and then made up with water to 1000 parts. The goods are bated 24-36 hours at a temperature of about 35° C, and the bate is strengthened for a second pack with about one-fifth of the original glucose, a new bate being made at the end of a week, and set with one part per thousand of the old one. A short bating of say 10 hours produced very nice harness-leather, but the general tendency was to make the goods looser and more spongy than a dung-bate. It is obviously not a matter of indifference whether old drench, or yeast, is used to start the fermentation, since in the latter case only alcohol could be produced directly by the ferment introduced, though this might be fermented later, by other accidental organisms, into acetic acid. These mixed bates, containing glucose, are however probably wrong in principle, since the true puering and bating bacteria will not thrive in presence of acids, and require nitrogenous nutriment.