Cassell's dictionary of cookery

"It is now easy to understand that, in the salting of meat, when this is pushed so far as to produce the brine above mentioned, a number of substances are withdrawn from the flesh which are essential to its constitution, and that it therefore loses in nutritive quality in proportion to this abstraction. If these substances be not supplied from other quarters, it is obvious that a part of the flesh is converted into an element of respiration — certainly not conducive to good health. It is certain, moreover, that the health of a man cannot be permanently sustained by means of salted meat, if the quantity be not greatly increased, inasmuch as it cannot perfectly replace, by the substances it contains, those parts of the body which have been expelled inconsequence of the changes of matter, nor can it preserve in its normal state the fluid distributed in every part of the body — namely, the juices of the flesh. A change in the gastric juice, and consequently in that of the products of the digestive process, must be regarded as an inevitable result of the long-continued use of salted meat ; and if, during digestion, the substances necessary to the, transformation of that species of food be taken from other parts of the organism, these parts must lose their normal condition." We come now to the preservation of food by the application of heat. This is the most successful method yet discovered and practically applied. It is properly termed ' ' preservation in vacito," and in its leading features is simple enough. The first simple process consisted in placing meat with a charge of water in a tin case with a small aperture, or " pin-hole " at the top, and then laying it- in boiling water nearly up to its top ; when the- steam has displaced the ail' the hole is stopped up with solder. This process has been improved upon, and there are now four methods, in a sense distinct from each other, of applying heat to the vessels and perfecting the preservation of their contents. These are — first, the ordinary Aberdeen process; second, the steam retort process ; third, the chloride of calcium process ; and fourth, Jones's patent vacuum process. " The older, or ordinary Aberdeen process," says the authority to whom we are indebted for the greater part of our infoi-mation on this subject, " is carried out as follows : — The raw meat, with or without a small quantity of fluid, is placed in tins, which are soldered down perfectly aii'-tight. They are let down on iron frames, or ' gridirons,' by means of pulleys into baths of boiling water, raised to a higher temperature by the addition of salt, and kept there for a certain time, according to the size of the tins ; the first bath of a six-pound tin, for instance, requiring two hours and a half. At the expiration of this time they are removed, and placed on a table near the bath, and the expanded air and vapour are let out through a minute aperture in the lid of the tin. This is done by one of the workmen touching with a hot iron the small piece of solder placed over the aperture, or ' pin-hole,' originally made in the lid. The steam at once rushes out, but within a few seconds another workman follows, and again solders down the ' pin-hole.' This part of the process is, in the vernacular, called ' brogging.' The tins are then returned to the boiHng brine for the same time as before, when they a