The body creates nothing of itself, either of material or of energy; all must come to it from without. Every atom of carbon, hydrogen, phosphorus, or other elements, every molecule of protein, carbohydrate, or other compounds of these elements, is brought to the body with the food and drink it consumes, and the air it breathes. Like the steam-engine, it uses the material supplied to it. Its chemical compounds and energy are the compounds and energy of the food transformed (Atwater). A proof of this is seen in the fact that when the supply from without is cut off, the body dies. The raw material which the body uses is the air and food which it consumes, the greater portion of which is digested and distributed, through the medium of the blood, to all parts of the body, to renew and nourish the various tissues and to supply the material for the different activities of life. =Ways in which Food Supplies the Wants of the Body.= Food supplies the wants of the body in several ways--(1) it is used to form the tissues of the body--bones, flesh, tendons, skin, and nerves; (2) it is used to repair the waste of the tissues; (3) it is stored in the body for future use; (4) it is consumed as fuel to maintain the constant temperature which the body must always possess to be in a state of health; (5) it produces muscular and nervous energy.[23] The amount of energy of the body depends upon two things--the amount in the food eaten, and the ability of the body to use it, or free it for use. With every motion, and every thought and feeling, material is consumed, hence the more rapid wearing out of persons who do severe work, and of the nervous--those who are keenly susceptible to every change in their surroundings, to change of weather, even to the thoughts and feelings of those about them. We easily realize that muscular force or energy cannot be maintained without nutriment in proper quality and amount. An underfed or starving man has not the strength of a well-fed person. He cannot lift the same weight, cannot walk as far, cannot work as hard. We do not as easily comprehend the nervous organism, and generally have less sympathy with worn-out or ill-nourished nerves than muscles, but the sensibilities and the intellectual faculties, of which the nerves and brain are but the instruments, depend upon the right nutrition of the whole system for their proper and healthful exercise. So many factors enter into the make-up of a thought that it cannot be said that any particular kind of food will ultimately produce a poem; but of this we may be sure, that the best work, the noblest thoughts, the most original ideas, will not come from a dyspeptic, underfed, or in any way ill-nourished individual.