268 Physiology. 



The Position of the Vocal Cords. While we are quietly 

 breathing, the vocal cords lie back, like low ridges, against 

 the sides of the larynx, and offer nearly the whole channel 

 of the larynx for the free passage of air for breathing pur- 

 poses. But when we wish to produce vocal sound, the 

 vocal cords are made to stand out farther from the side 

 walls, and interfere with the free passage of the air. The 

 vocal cords are attached close to each other in front, but 

 at the back of the larynx they diverge widely, forming a 



. Epiglottis 



_ False Vocal Cords 



True Vocal Cords 



Glottis Narrowed, High Note Glottis Wider. Quiet Breathing 



Fig. 105. The Vocal Cords, seen from Above. 



letter V, with the angle of the V just back of Adam's 

 apple. " When changes in the voice or in breathing are 

 being made, the white glistening vocal cords may be seen 

 to come together or to go apart like the blades of a pair of 

 scissors." In a high note the cords are close together and 

 nearly parallel. As the air is forced past the edges of the 

 vocal cords, they are set in vibration, and produce the 

 sound called the voice. 



Illustration of the Vocal Cords. The principle of the action of the 

 vocal cords can be illustrated by the common toy known as the squeak- 

 ing balloon, or "squawker." Here the air is driven out past a band of 

 rubber stretched across the inner end of the tube. If instead of one 

 band with both edges free, we were to tie on the inner end of the tube 

 two bands of rubber, each covering the outer edge of the tube, leaving 

 the inner edge of the rubber free, and with the two bands touching at 

 one end and considerably separated at the other end, we would have a 

 pretty fair resemblance to the larynx 



