II. Notes on the Constitution and Mode of Action of the Dung Bate in Leather Manufacture. Read before the Nottingham section of the Society of Chemical Industry, Oct. 26, 1898.
In a paper read before the Society of Chemical Industry (J.S.C.I., 1894, 219), the author gave an outline of the bating process as far as he had then investigated it. Further researches have shown that, although the views then put forward must be somewhat modified, in the main they are correct.
In 1895–96 a series of experiments was undertaken with a view of ascertaining how much of the reducing action of the bate was due to: (1) the chemical constituents; (2) the bacteria; (3) the digestive ferments and enzymes.
The puer used was dog dung obtained freshly every week from hunting kennels. It contained on an average: water, 85 per cent.; organic matter, 10 per cent.; mineral matter, 5 per cent.; about 3 per cent. of the organic is soluble and about 1 per cent. of the mineral matter.
According to Gamgee (Phys. Chem. 2), a dog fed on flesh diet excretes from 27 to 40 grm. of fæces in 24 hours, of which 12·9 grm. are solids. On a bread diet the amount of fæces is much more.
An ultimate analysis gave the following results:—
| — | Bread Diet | Meat Diet |
| C | 47·39 | 43·44 |
| H | 6·59 | 6·47 |
| N | 2·92 | 6·50 |
| O | 36·08 | 13·58 |
| Mineral matter | 7·02 | 30·01 |
These figures alone are sufficient to show what variable quantity is the puer employed in a tannery.