Appertizing, or, The art of canning : its history and development / by A.W. Bitting.
- Arvill Wayne Bitting
- Date:
- 1937
Licence: In copyright
Credit: Appertizing, or, The art of canning : its history and development / by A.W. Bitting. Source: Wellcome Collection.
36/870 (page 32)
![augmented, if the air be, at the same time, dry, and a frequent change of surface occur in it. Rut in this mode of preservation, the juices of the meat are in great part dissipated, and its flavour is considerably impaired : Neither, by the subsequent restoration of moisture, is the animal fibre re¬ stored to its former state of freshness, as happens to frozen substances from the reapplication of heat. Such substances are therefore less nutri¬ tious than in their recent state, and are with more difficulty acted on by the digestive organs. The employment of this method in the preservation of vegetable sub¬ stances, is practised to a great extent. The tendency to putrefaction in these bodies is much less than in animal substances; and the smallness of their hulk, or rather the thinness of their form, favours much their com¬ plete desiccation. Neither, by this process, do their more fixed ingredi¬ ents sufifer so much loss or change of properties as those of animal sub¬ stances ; and consequently, their nutritive powers are not so much im- ])aired. The most important vegetable substances preserved in this way, are the Gramineae, in the state either of corn or hay. The stems and seeds of these vegetables keep, as is well known, for a long time, if they are well got in, and properly stored. In the condition of grain, it is desirable that no alteration should take place, after it is oiice put into stack; but the qualities of hay are certainly much improved by its undergoing a gentle fermentation. In those districts of England where cattle are fattened on hay alone, great attention is given, that, in the making of it, the natural juices be so far preserved that it may properly heat, as it is called, in the stack. By this process of heating, the colour of the hay is deepened, its weight is increased, and it is rendered sweeter, the mucilage and starch of the stems and seeds being probably converted into saccharine matter, as occurs in the process of malting, or in the methods lately discovered of converting starch into sugar by the long-continued operation of heat and moisture. Sometimes, indeed, from unfavourable seasons, or from negli¬ gence in the making, the hay is not sufficiently dried ; and the fermentation then excited disengages so much heat as to consume the whole by a slow and smothered combustion, reducing it to the state of a dry charcoal. If, at this period, air be admitted into the mass, it breaks out into flame. The great heat thus manifested arises probably from the condensation of water, which, during the fermentation, is found entirely to disappear. Mr. Leslie has shown, that the simple absorption of a few drops of water, by a bit of very dry wood, paper, or linen, produces a considerable elevation of temperature; and the heat Iil:)erated when water is rendered solid in the slaking of lime is familiar to every one. Some vegetables, however, as potatoes and turnips, may be preserved a long time without change, though containing a large portion of water; 1)ut could they be deprived of this water, their preservation would be more easily and certainly accomplished, and their transportation greatly facili¬ tated. A process for effecting this i)urpose, was proposed some years ago, by Mr. Forsyth, advocate. It consisted in first cutting or breaking the ])otatoes into small pieces, and then dissipating their water, by exposing them on a metallic ])late, heated by the steam of boiling water. In this man¬ ner, they may be rendered dry, without risk of burning or scorching; and the flour or meal they yield, is said to have no disposition to attract moist¬ ure; and if closely {racked, may be preserved for any length of time. This](https://iiif.wellcomecollection.org/image/b29980768_0036.jp2/full/800%2C/0/default.jpg)
