PROXIMATE CONSTITUENTS OF FOOD. 483 



added, the vegetable oils, whether solid or fluid, such as cocoa-nut oil, 

 olive oil, and almond oil. 



4. Amylaceous or starchy, gummy, and saccharine substances. 

 These comprehend the different varieties of starch, such as potato 

 starch, arrow-root, sago, tapioca, rice, and the starchy portion of wheat 

 and other grain. The gummy substances include, besides all the nat- 

 ural gums and mucilages of fruits and vegetables, the substance named 

 dextrin, which results from the transformation of starch, cellulose or 

 lignin, and also pectin, a constituent of succulent vegetables. The 

 sugars are the common, or cane sugar, and grape sugar, derived, as 

 such, from vegetables, or produced by the transformation of starchy 

 or gummy substances. There are also the sugar of honey, which is an 

 animal preparation ; the glycogen, or animal starch, often present in 

 flesh, but chiefly found in the substance of the liver ; inosite, or sugar 

 of muscle ; and lastly, the sugar of milk, lactose, or lactin, which, 

 though usually formed in the animal economy, can also be artificially 

 made, by acting upon starch with certain acids, at a high temperature. 



5. Stimulating substances. These consist of three classes : viz., 

 first, the various kinds of spices or condiments, the active properties of 

 which depend usually upon volatile or essential oils ; secondly, the 

 parts of vegetables, whether the leaves or berries, which contain the 

 alkaloids, thein, caffein, or theobromin, which are found in tea, coffee, 

 cocoa, and the Paraguay tea. With these should probably be associ- 

 ated, the substances named extractives, viz., cerebric acid, which exists 

 in nervous substance, and also in corn, especially in Indian corn ; cre- 

 atin and ereatinin* which are found in the juice of meat, in the brain, 

 and in the blood, the former being converted in the system into the 

 latter ; both of these act either as stimulants, or by retarding chemi- 

 cal change and loss in the albuminoid tissues. The thein and allied 

 bodies certainly stimulate the heart, muscles, and nervous system. 

 Thirdly, there are the various alcoholic beverages made by the fermen- 

 tation of saccharine substances, such as mead, beer, cider, wine, and 

 the stronger alcoholic fluids or spirits distilled from various fermenting 

 saccharine vegetable juices. These substances are probably not im- 

 mediately nutritive, or able to supply the waste of material, but appear 

 rather to act as stimuli to the nervous system, and also by preventing 

 waste. To these may be added, the several ethers formed in ripe 

 fruits, and in wines, from the action of the organic vegetable acids on 

 alcohol. This class may also include certain organic vegetable acids, 

 such as the acetic acid of vinegar, the tartaric, malic, racemic, oxalic, 

 and citric, derived respectively, from grapes or raisins, apples, goose 

 berries, the esculent rhubarb, and the lemon, lime, and orange ; and 

 lastly, the lactic acid existing in sauer-kraut, and in fermented cucum- 

 bers or beans, all of which are favorite articles of diet with some na- 

 tions. The prevalence of the desire for acids with the food is remark- 

 able. Lactic acid also exists in sour milk, which is much consumed, 

 and in the juice of meat, together with paralactic and inosinic acids. 



6. Saline, earthy, and mineral substances. These, which are, in 

 certain proportions, essential articles of food, soda for the blood, potash 

 for the muscles, and lime for the bones, consist of the chlorides of 



