Exercise (physical activity) is a requisite of health, strength and development throughout the animal kingdom. Full development cannot be achieved without it. How suicidal, then, for us to cramp our bodies with tight clothes that do not admit of freedom of movement and confine ourselves indoors in inactivity. Even the caged bird, though limited in its sphere, skips from perch to perch for hours, for exercise, while we sit practically motionless for hours at a time at a desk, never getting any more exercise than is required to walk to the water fountain and back.

The incessant playful activities of young animals constitute a course in physical training that meets nearly all of their needs in this particular. Our own young are cooped up in class rooms and required to remain physically idle.

We have abandoned the old practice of tightly bandaging infants and confining them in swaddling clothes until they become blue from lack of air and from interference with circulation. We are killing fewer infants today than formerly partly because of having abandoned this cruel practice. We let them roll and tumble about and kick and use their limbs and body in freedom. Instinctively, they are as active and playful as the young kitten or puppy, or the fledglings in the nest flapping their wings as if trying to fly. Just as the fledgling thus educates his muscles for the act of flying, so the infant and young child is busy educating its muscles for future activities. Unfortunately, we interrupt this physical education at an early age by confining the children in class rooms and we do not adequately compensate for the enforced idleness.

Writing in the Herald of Health, January 1865, A. J. Wood, M.D., said: "Of all the Hygienic agencies as Food, Light, Water, Air, Sleep, etc., that should be used in correcting disordered action, none are more important than exercise." Obviously, this use of exercise in correcting physiological activity could not apply to acute disease. Exercise or physical activity serves its legitimate function in health and in many states of chronic disease.

Inertia, slothfulness and inactivity permit the body to become soft and flabby, its structures to deteriorate, its functions to weaken and its efficiency to decrease. The neglect of exercise by the medical profession was but one more of its crimes against the integrity of life. Graham pointed out that physical activity or exercise is absolutely essential to a proper flow of the body's fluids, hence to good nutrition. In its effects, exercise involves the whole body and not merely its muscles.