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. Bad Effects of Shallow Breathing Very few people breathe correctly. Some, especially women, with tight skirtbands and corsets pressing on their vital organs, use only the upper part of their lungs. Others breathe only with the lower part and with the diaphragm, leaving the upper structures of the lungs inactive and collapsed. In those parts of the lungs that are not used, slimy secretions accumulate, irritating the air cells and other tissues, which become inflamed and begin to decay. Thus a luxuriant soil is prepared for the tubercle bacillus, the pneumococcus and other disease-producing bacilli and germs. This habit of shallow breathing, which does not allow the lungs to be thoroughly permeated with fresh air, accounts in a measure for the fact that one-third of all deaths result from diseases of the lungs. To one individual perishing from food starvation, thousands are dying from oxygen starvation. Lung culture is more important than other branches of learning and training which require more time and a greater outlay of time, money and effort. In the Nature Cure regimen, breathing exercises play an important part. Breathing Exercises General Directions The effectiveness of breathing exercises and of all other kinds of corrective movements depends upon the mental attitude during the time of practice. Each motion should be accompanied by the conscious effort to make it produce a certain result. Much more can be accomplished with mental concentration, by keeping your mind on what you are doing, than by performing the exercises in an aimless, indifferent way. Keep in the open air as much as possible and at all events sleep with windows open.