THE VOICE. 311 



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 approximated 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 

 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 



Epiglottis 

 False Vocal Cords ... 



True Vocal Cords ~ 



i 

 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. 



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 touch- 

 ing at one end and considerably separated at the other end, we would 

 have a pretty fair resemblance to the larynx. 



Reenforcement of Vocal Sound. As in many musical 

 instruments, the vibrations of the membrane alone would 

 be too feeble to have much effect. In the violin, piano, 

 drum, etc., the vibrations are reenforced by the vibration 

 of a body of air contained within. So here the vibrations 

 of the cords are reenforced and modified by the air spaces 

 above. 



Loudness of Voice. The loudness of the voice depends 

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



