THE NATURE AND INFLUENCE OF FOODS. 443 



to those of nutrition, which are not common to all ; so that some 

 foods more than others influence the action of the heart, lungs, skin, 

 brain, bowels, or other vital organ, while others have antagonistic 

 qualities, so that one may destroy certain effects of another. 



Foods are derived from all the great divisions of Nature and nat- 

 ural products, as earth, water, and air, solids, liquids, and gases ; and 

 from substances which are living and organic, or inanimate and inor- 

 ganic. The popular notion of food as a solid substance derived from 

 animals and vegetables, while comprehensive, is too exclusive, since 

 the water which we drink, the air which we breathe, and certain min- 

 erals found in the substance of the earth, are of no less importance 

 as foods. 



It is, however, of great interest to note how frequently all these 

 are combined in one food, and how closely united are substances which 

 seem to be widely separated. Thus water and minerals are found in 

 both flesh and vegetables, while one or both of the component parts 

 of the air, viz., oxygen and nitrogen, are distributed through every 

 kind of food. Hence, not only may we add food to food to supply the 

 wants of the body, but we may within certain limits substitute one for 

 another as our appetites or wants demand. The necessity for this in 

 the economy of Nature is evident, for, although a good Providence 

 has given to man an almost infinite number of foods, all are not found 

 everywhere, neither can any man obtain all foods found around him. 



Further, there seems to be an indissoluble bond existing between 

 all the sources of food. There are the same classes of elements in 

 flesh as in flour, and the same in animals as in vegetables. The vege- 

 table draws water and minerals from the soil, while it absorbs and in- 

 corporates the air in its own growth, and is then eaten to sustain the 

 life of animals, so that animals gain the substances which the vege- 

 table first acquired. But, in completing the circle, the vegetable re- 

 ceives from the animal the air which was thrown out in respiration, 

 and lives and grows upon it, and at length the animal itself, in whole 

 or in part, and the refuse which it daily throws off, become the food 

 of the vegetable. Even the very bones of an animal are by the aid 

 of Nature or man made to increase the growth of vegetables, and 

 really to enter into their structure ; and, being again eaten, animals 

 may be said to eat their own bones and live on their own flesh. Hence 

 there is not only an unbroken circle in the production of food from 

 different sources, but even the same food may be shown to be pro- 

 duced from itself. Surely this is an illustration of the fable of the 

 young phoenix arising from the ashes of its parent ! 



Food is required by the body for two chief purposes, viz., to gen- 

 erate heat and to produce and maintain the structures under the in- 

 fluence of life and exertion. The importance of the latter is the more 

 apparent, since wasting of the body is familiarly associated with 

 decay of life ; but the former is so much the more urgent, that, whereas 



