Amongst other agents which have been found serviceable as antiseptics, and for which from time to time numerous patents have been taken out, are nitrate of potash, acetate and hydrochlorate of ammonia, the sulphates of soda and potash, and bisulphate of lime. The writer remembers partaking, some years since, of some Canadian turkey, which had been preserved by means of this latter substance, and the turkey having been killed some two months before being eaten. It was perfectly sound and of excellent flavour. In this instance the bird had been sent from Canada, with several others, packed in waterproof casks, filled up with a weak solution of bisulphite of lime.
In some cases the saline solution is merely brushed over the outside of the meat; whilst in others it is injected into the substance of the flesh.
Thiebierge’s process consists in dipping the joints for five minutes into dilute sulphuric acid, of the strength of about ten of water to one of acid. The meat after being taken out is carefully wiped and dried, and is then hung up for keeping.
Sulphurous acid also forms the subject of several patents for the preservation of meat. In the process of Laury, for which a patent was taken out in 1854, the gas was introduced into the vessels containing the food. In that of Belford, for which a provisional specification was granted the same year, the meat was soaked for 24 hours in a solution of sulphurous and hydrochloric acids (the latter being in the proportion of a hundredth of the volume of the former). The addition of the hydrochloric acid was made with the intention of decomposing any alkaline sulphites that might be formed by the combination of the alkaline salts of the meat with the sulphurous acid.
Dr Dewar’s process, which is very similar to the foregoing, proposes, instead of exposing
the meat to sulphurous acid fumigation, to immerse it in a solution of the acid of the same strength as that of the British Pharmacopœia. On being taken out of the liquid the meat, or other article, is, as speedily as possible, dried at a temperature not exceeding 140° F., so that the albumen may be preserved simply in a desiccated, and not in a coagulated condition.
In the patent of Demait, which dates from 1855, the meat was directed to be hung up in a properly constructed chamber, and exposed for some time to the action of the gas. More recently, Professor Gamgee has taken out a patent, which is a modification of Demait’s, and which consists in hanging up the carcase of the animal, previously killed when under the influence of carbonic oxide, in a chamber filled with this latter gas, to which a little sulphurous acid has been added, the chamber having been first exhausted of air. The carcase is allowed to remain in the chamber from 24 to 48 hours, after which it is hung in dry air. It is stated that meat subjected to the above treatment has been found perfectly sound and eatable after an interval of five months.
M. Lanjorrois proposes to preserve animal substances from decay by the addition to them of 1 per cent. of magenta. He states the process had been applied to slices of beef, which, after being kept for several months, yielded, after being washed and boiled, very good soup. Commenting on this suggestion for the preservation of meat, the ‘Chemical News’ very sensibly and properly remarks: “It is to be hoped the magenta employed will be free from arsenic.”
The patent of M. de la Peyrouse (which dates from 1873) also consists in excluding the air by enveloping meat in fat. In this process, however, the fat is mixed, when in a melting condition, with a certain quantity of the carbonates of sodium, potassium, and ammonium, as well as with some chlorides of magnesium and aluminium, with the object of preventing the fat becoming rancid and decomposing, and thus imparting a disagreeable flavour to the meat.
In M. George’s process the meat is partially dried, and then steeped in successive waters containing hydrochloric acid and sulphate of soda.