1. It has been shown that the fermentation investigated is due to a specific organism, of which we find no account, and which, pending further experiments, we have therefore provisionally named Bacterium furfuris.
2. That the starch and nitrogenous bodies in the bran, alone take part in the fermentation, the starch being first transformed into glucoses and dextrin by the action of an unorganised ferment or ferments; the glucoses and nitrogenous bodies only, being decomposed by the bacteria, with the formation of formic, acetic, butyric, and lactic acids, and the simultaneous evolution of hydrogen, carbon dioxide, nitrogen, and a small quantity of sulphuretted hydrogen. The following table shows the quantities found in an experimental drench per 1000 c.c.
| Grm. | |
| Formic acid | 0·0306 |
| Acetic acid | 0·2402 |
| Butyric acid | 0·0134 |
| Lactic acid | 0·7907 |
| ──── | |
| Total | 1·0749 |
| ──── |
We find in actual work that the quantity of acid produced varies from 1 to 3 grm. per litre.
3. That if these acids are applied to the skins in the same proportions as they occur in the drench, the action on them is the same, and much quicker than an ordinary drench.
4. That the gas therefore, has no action on the skins per se, with the exception of floating and distending them, and so enabling them better to take up the acids.
We are indebted to Mr. H. R. Procter, of the Yorkshire College, Leeds, and to Dr. Percy F. Frankland for valuable suggestions in carrying out some of the work.
II. On a Pure Cultivation of a Bacillus Fermenting Bran Infusions. By J. T. Wood and W. H. Willcox, B.Sc.(Lond.).
Reprinted from the Journal of the Society of Chemical Industry, 30th June, 1897, No. 6, vol. xvi. p. 510.
Isolation of Pure Culture.—In our previous communication on bran fermentation as applied in the manufacture of light leathers,[173] we gave an account of the actual fermentation and its products, together with the mode of action on the bran and on the skins for which this fermentation is used, reserving to the present paper an account of the products of a pure cultivation of the bacteria causing the fermentation.