With every inhalation, air is sucked in through the windpipe or trachea, which terminates in two tubes called bronchi, one leading to the right lung, one to the left. The air is then distributed over the lungs through a network of minute tubes, to the air cells, which are separated by only a thin membrane from equally fine and minute blood vessels forming another network of tubes.

The oxygen contained in the inhaled air passes freely through these membranes, is absorbed by the blood, carried to the heart and thence through the arteries and their branches to the different organs and tissues of the body, fanning the fires of life into brighter flame all along its course and burning up the waste products and poisons that have accumulated during the vital processes of digestion, assimilation and elimination.

After the blood has unloaded its supply of oxygen, it takes up the carbonic acid gas which is produced during the oxidation and combustion of waste matter and carries it to the lungs, where the poisonous gases are transferred to the air cells and expelled with the exhaled breath. This return trip of the blood to the lungs is made through another set of blood vessels, the veins, and the blood, dark with the sewage of the system, is now called venous blood.

In the lungs the venous blood discharges its freight of excrementitious poisons and gases, and by coming in contact with fresh air and a new supply of oxygen, it is again transformed into bright, red arterial blood, pregnant with oxygen and ozone, the life-sustaining elements of the atmosphere.

This explains why normal, deep, regular breathing is all-important to sustain life and as a means of cure. By proper breathing, which exercises and develops every part of the lungs, the capacity of the air cells is increased. This, as we have learned, means also an increased supply of life-sustaining and health-promoting oxygen to the tissues and organs of the body.