The purposes of food are to promote growth, to supply force and heat, and to furnish material to repair the waste which is constantly taking place in the body. Every breath, every thought, every motion, wears out some portion of the delicate and wonderful house in which we live. Various vital processes remove these worn and useless particles; and to keep the body in health, their loss must be made good by constantly renewed supplies of material properly adapted to replenish the worn and impaired...