Finally gall in bating the derms may be of great importance inasmuch as its acids form easily soluble lime salts. Extensive experiments have shown that gall, as such, is adapted to dissolve a comparatively large quantity of lime. In hard water an addition of gall prevents the precipitation of calcium carbonate, and the roughening of the derm, which, for instance, has been noticed when pure bacteria cultures are employed, is prevented by the addition of gall. The intestinal juice contains in addition to carbonates and alkalis, enzymes which again exert a slighter bating action on the hide than those of gall. The intestinal juice alone has a similar action to pancreatic juice, but if intestinal juice be added to pancreatic juice, the most powerful enzyme of pancreatic juice, namely the albumen-decomposing trypsin is energised, and only in this way does the pancreatic juice fully acquire the property of dissolving albuminous substances.[150] [150] 1. See Abderhalden, “Text-book of Physiological Chemistry,” 1906, page 556. The proportions in which such mixtures best develop their actions, are those which obtain in animal organisms; the temperature also especially plays a great part. The maximum temperature lies about 40° C. From the above statements it is evident that it is possible to produce various actions with the juices of the pancreas, gall and the intestines, quite dependent on which are considered the most important in the bating. Similarly, as the proteolytic action of the mixture of the three juices may be increased or diminished by using larger or smaller quantities of intestinal juice and pancreas, the fat-decomposing and fat-dissolving action of the mixture may also be increased or diminished by using larger or smaller quantities of gall, and of gall and pancreas respectively. Finally the quantity of the gall to be added is decided according to the amount of lime contained in the water employed in the bating. Experience has shown that a relatively small addition of gall will act very advantageously. It must be especially remarked that artificial bates made in this way are extremely cheap as compared with the natural dogs’ dung, as gall and intestinal juice may be procured at very low prices and a considerably smaller quantity of the energised, more expensive, pancreatic juice is necessary than, for instance, would be necessary if this juice were employed in a pure condition.