No one of these agents alone molds the tone, but their proper relation to each other constitutes resonant molds as definite as those into which melted ore is cast to give it form and stamp. This proper relationship cannot be secured by exercising the organs in any strictly mechanical way, but only by forming definite ideal tones in the mind and exercising the voice while these ideal tones are firmly fixed as steady objects of thought. If these mental objects drop from the mind at any time during the vocal practice, no mechanical ingenuity can possibly take their places in rightly affecting the voice. Later in this work, I shall more fully elaborate this point. =_RELATION OF THE PROPER USE OF THE VOICE TO HEALTH._= Many years of observation and study have convinced me that the voice exerts a powerful effect upon the whole physical system. It either builds up the body, sustains its power and adds to its health, or it devitalizes the body and brings a dangerous strain upon the entire system. The voice cannot be a reporter of the person, mental and physical, without holding the most delicate relations to mind and body. The exercise of the voice subtly and vitally affects the organs that promote health and give life. I could give many illustrations showing that the wrong use of the voice has injured health, and that its right use has promoted health; but if the principles involved in this chapter are fully understood, I need not relate incidents to prove that the voice is a life-giver or a death-dealer, depending entirely upon _how_ it is used. The Greeks were taught the right use of the voice as a part of their physical, intellectual, and moral culture. In modern times we have neglected voice culture to a very great extent, and have suffered much ill health in consequence. _RELATION OF THE PROPER USE OF THE VOICE TO THE VITAL ORGANS._ EFFECT OF THE VOICE UPON THE LUNGS. 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.