CHAPTER XI
AUXILIARIES IN FASTING
BREATHING. Nature has provided in the air that surrounds the earth a plentiful supply of oxygen, a gas that is essential to the maintenance of human life. Its function lies in replacing carbonic acid, a poisonous gas developed within the body by the breaking down of tissue, and delivered to the lungs in venous blood. In the process of breathing, oxygen is inhaled and appropriated, while carbonic acid is expelled. The act of respiration exposes the blood to the air, and by mutual diffusion the two operations of oxygenating the blood and freeing it from carbonic acid are accomplished at one and the same time. The muscular movements of respiration are not dependent upon the will, as the same process goes on in sleep and in other unconscious states. The number of respiratory movements in health varies from fourteen to eighteen per minute, and besides carbonic acid, watery vapor and a small
