Great wisdom is exhibited in the construction of the human lungs. In the arrangement of the air cells, the greatest possible amount of surface is presented in order that the air may freely enter the blood. The lungs are largely made up of blood vessels, bronchial tubes, and air cells. When a person breathes, the oxygen, entering the lungs through the trachea and the bronchial tubes, penetrates the thin walls of these cells and passes at once into the blood. When the blood enters the lungs it is dark in color, but when it leaves the lungs it is of a light vermilion hue. The oxygen which has been taken into the lungs has wrought this change. So wonderful is this element of nature that some have called it life. If there is an elixir of life in the material world surely it is oxygen, for it has to do minutely and intimately with every power of the human body. The more a person breathes this oxygen as it is mixed in the common air, the more life and power he possesses.
It is essential to perfect health that every avenue to the lungs should be kept open and free, and that the air cells should be kept clear, for if the walls of the cells thicken, oxygen cannot penetrate them. If these cells are not properly filled during respiration, the walls thicken, and substances collect in the cells. If any trouble occurs in the air cells, except for traumatic reasons, it will first be found in the apexes of the lungs. In the production of tone, whether on a low, high, or medium pitch, the vocal cords are drawn so closely together that the air cannot immediately escape from the lungs; therefore, unable to get out readily, it is pressed up into the apexes of the lungs by the expiratory muscles, filling the air cells to the utmost, thus keeping them clear and their walls thin and healthy. In correct singing or speaking, the apexes of the lungs are filled with air. Tubercule seeks devitalized tissue for its development. Therefore tuberculosis usually begins in the apexes of the lungs because they are not kept clear and healthy through proper respiration and vocal exercise. Voice was given to man to make him strong and expressive, to give him life and power.
THE EFFECT OF THE VOICE UPON THE STOMACH.
The stomach is the principal organ of digestion. Out of the nutriment taken into it all the tissues of the body are renewed. It lies under the diaphragm, and is held in place by the abdominal muscles. The stomach is moved during respiration, descending with every inspiration, and rising with every expiration.
In addition to this exercise during the production of tone, the stomach is held firmly between the diaphragm and abdominal muscles. At the close of the tone the muscles which thus hold the stomach relax.
A view of the Organs of Digestion, opened in nearly their whole length; a portion of the œsophagus has been removed on account of want of space in the figure; the arrows indicate the course of substances along the canal: 1, the upper lip, turned off the mouth; 2, its frænum; 3, the lower lip, turned down; 4, its frænum; 5, 5, inside of the cheeks, covered by the lining membrane of the mouth; 6, points to the opening of the duct of Steno; 7, roof of the mouth; 8, lateral half-arches; 9, points to the tonsil; 10, velum pendulum palati; 11, surface of the tongue; 12, papillæ near its point; 13, a portion of the trachea; 14, the œsophagus; 15, its internal surface; 16, inside of the stomach; 17, its greater extremity or great cul-de-sac; 18, its lesser extremity or smaller cul-de-sac; 19, its lesser curvature; 20, its greater curvature; 21, the cardiac orifice; 22, the pyloric orifice; 23, upper portion of duodenum; 24, 25, the remainder of the duodenum; 26, its valvulæ conniventes; 27, the gall-bladder; 28, the cystic duct; 29, division of hepatic ducts in the liver; 30, hepatic duct; 31, ductus communis choledochus; 32, its opening into the duodenum; 33, ductus Wirsungii, or pancreatic duct; 34, its opening into the duodenum; 35, upper part of jejunum; 36, the ileum; 37, some of the valvulæ conniventes; 38, lower extremity of the ileum; 39, ileo-colic valve; 40, 41, cœcum, or caput coli; 42, appendicula vermiformis; 43, 44, ascending colon; 45, transverse colon; 46, 47, descending colon; 48, sigmoid flexure of the colon; 49, upper portion of the rectum; 50, its lower extremity; 51, portion of the levator-ani muscle; 52, the anus.