PREPARATION OF FOOD. 487 



heat, whether applied directly, as in roasting or baking, or indirectly, 

 through the agency of water, as in boiling, is to change the molar and 

 molecular condition of the cooked substances. Thus, the albuminoid 

 bodies are more or less coagulated ; the gelatin-yielding tissues become 

 swollen and partially gelatinized ; fat-cells are ruptured, and fats are 

 rendered more fluid; the various kinds of starch have their granules 

 pulpified, and the cellulose and lignin of vegetable tissue, are broken 

 up, so as to liberate the contents of the cells. The general result of 

 cooking is to disintegrate, and separate the animal tissues into minuter 

 portions, and to destroy the continuity of vegetable textures. Cook- 

 ing, therefore, produces both physical and chemical changes in the 

 food, the tendency of which is to facilitate mastication, and the subse- 

 quent action of the digestive fluids, thus rendering them softer and 

 more digestible. 



Man also has discovered and employed as drinks, numerous bever- 

 ages, obtained from the natural products of nearly every climate, by 

 the spontaneous, or the induced, alcoholic fermentation of saccharine 

 matter, whether this saccharine matter exist ready formed, as in the 

 juice of the grape, or other fruits, or whether it be artificially gene- 

 rated by the transformation of starch into sugar, as happens when 

 barley is manufactured into malt. Besides consuming the immediate 

 products of fermentation, in the shape of wine, beer, and other fer- 

 mented liquors, distillation is had recourse to by Man, in order to pro- 

 cure, in a more concentrated state, the spirit, or alcohol, generated in 

 that fermentation. Man, therefore, not only employs the art of cook- 

 ing, but also the chemical processes of fermentation and distillation, 

 in the preparation of food, using this term in its widest sense. The 

 precisa destination of alcohol in the system will be hereafter discussed. 



Other beverages are made by simple infusion or decoction, so as to 

 dissolve out certain nutrient or stimulating substances, as from tea, 

 roasted coffee, cocoa, and other vegetable products. Sugar is used in 

 solution, in the sweetening or preservation of fruits, in cookery, and 

 in preparing various articles of confectionery; it is a highly important 

 and useful form of food. Common salt, being contained in the blood 

 and tissues, is an essential article of food. Its use as a condiment, 

 and also as a preservative, especially of animal substances employed 

 as food, is very old and general. All animals are fond of salt. Its 

 injurious influence on the quality of the food preserved in it, has long 

 been recognized, the continued use of such food, in the form of salted 

 provisions, favoring the production of scorbutus or scurvy. Salt hardens 

 the muscular and other tissues preserved in it, by abstracting water 

 from them ; with this water, which appears in the brine, the soluble 

 potash and magnesia salts, as well as the creatin and other extractives, 

 are likewise abstracted from the meat, and pass into the preservative 

 liquor, thus leaving the meat destitute of many alimentary principles 

 essential to health. Indirectly, this may be the cause of -scurvy; or 

 that disease may partly depend on the direct action of the common 

 salt taken in excess. 



The employment of vinegar as a condiment, and the use of vegetable 

 acids, those universally favorite articles of diet, aid in the solution of 



