Larynx

a cartilaginous box placed between the windpipe and the tongue, and inclosing membranous bands--the vocal cords. All air taken into or sent out of the lungs must pass through this box; and it is the vibrations of the elastic bands in this box that produce voice. In ordinary breathing the vocal cords are separated so that when the air passes through them no sound is produced. In talking, singing, or shouting, the cords are drawn inward and backward by the cartilage--muscles--so that a very narrow slit is formed, and the air, in passing, is forced out. This sets the edges of the bands in vibration, and the vibrations produce sound. The loudness of the sound made depends upon the force with which the air is driven between the cords. The pitch of the sound depends upon the tension of the cords. If these are stretched, the pitch is high; if relaxed, the pitch is low. The quality of the voice--whether harsh or sweet--depends upon several conditions, such as the form and condition of the throat, nose, and mouth cavities, and the general health of the body. Articulate speech is the result of changes in the resonance cavities, mouth, throat, and nose, and in the modifications produced in the voice by the lips, tongue, and teeth. The larynx of a child is smaller proportionately than that of an adult. At the age of twelve to fifteen years the larynx widens and the cords lengthen. This change causes a deepening of the tone of the voice. Clearness and quality of voice can be improved by practice. See Adam'S Apple