On the composition of food and how it is adulterated : with practical directions for its analysis / by W. Marcet.

  • Marcet, W. (William), 1828-1900.
Date:
1856
Catalogue details

Licence: Public Domain Mark

Credit: On the composition of food and how it is adulterated : with practical directions for its analysis / by W. Marcet. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    of cold is also extensively used to prevent too rapid a decomposition of food in hot weather, as in the case of fish, butter, &;c. I have nothing to add on the state of food thus preserved; if it has not undergone the sHghtest decomposition, it is exactly in the same condition as when quite fresh, and consequently, as healthy and nutritive. 2. Preservation by exclusion of air.—There is no doubt that if an article of food be so prepared, the atmosphere can have no access whatever to it, this food will pre- serve for a very considerable length of time ; the practical objection attending this method is the difficulty of pre- venting completely the contact of the atmosphere with organic substances. Articles of food intended for preserva- tion, by exclusion of air, may be fluid or solid \ if fluid, they are first to be thoroughly boiled, in order to expel the air they may contain dissolved within them, and next to be intro- duced through a small opening into metallic or earthenware vessels; when the vessel is overflowing, the opening must be soldered or stopped up ; it is difficult, however, to pre- vent a very small quantity of air from being enclosed in the vessel. Such liquids, when kept in metal jars, may dissolve small quantities of the metal of which the vessel consists, and thereby acquire a very objectionable character. Food is preserved on a very large scale by the ex- clusion of air and destruction of the small amount of oxygen contained in the jar; this is known as Appert's method. For this purpose, the jars, or boxes of tin plate, containing the article for preservation, are thoroughly corked or soldered, care being taken that the vessel be quite full, they are afterwards immersed in boiling water for a certain length of time; the air left in the jar is thereby de-