VOCAL COEDS. 325 



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

 and nearly parallel. As the air is forced past the approxi- 

 mated edges of the vocal cords, they are set in vibration, and 

 produce the sound called the voice. The principle of the 

 action of the vocal cords can be illustrated by the common 

 toy known as the the squeaking 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, 



Epiglottis 

 False Vocal Cords 



True Vocal Cords 



Glottis Narrowed, High Note Glottis Wider, Quiet Breathing 



Fig. 95. The Larynx, as Seen by Means of the Laryngoscope, in Different 

 Conditions of the Glottis. 



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. As in many musical instruments, the vibrations of 

 the membrane itself alone would be too feeble to have much 

 effect. In the violin, piano, drum/ etc., the vibrations are re- 

 enforced by the vibration of a body of air contained within. 

 So here the vibrations of the cords are reenforced and modi- 

 fied by the air spaces above. The loudness of the voice de- 

 pends on the force with which the air is driven past the cords, 

 together with the size and condition of the cords themselves. , 

 Pitch depends on the rapidity of the vibrations, which is de- 



