340 THE HUMAN BODY. 



are numerous, and are arrange'd (1) to pull the arytenoid 

 cartilages towards one another and so narrow the glottis 

 behind; then air forced through the narrowed slit sets the 

 cords vibrating and produces voice. (2) To increase the 

 distance between the arytenoid cartilages behind and the 

 thyroid in front: as the vocal cords are attached to both, 

 this action stretches and tightens them, and so raises the 

 pitch of the voice. (3) To pull the front of the thyroid 

 cartilage nearer the arytenoids and so slacken the cords and 

 lower the pitch of the voice. (4) To separate the arytenoid 

 cartilages, and with them the vocal cords, and thus widen 

 the glottis and allow air to pass through it without pro- 

 ducing voice. 



The Range of the Human Voice from the lowest note 

 (/"of the unaccented octave) of an ordinary bass to the 

 highest note (g on the thrice-accented octave) of a fairly 

 good soprano is about three octaves: the former note is 

 produced by 176 vibrations per second, the latter by 1584. 

 Celebrated singers of course go beyond this limit in each 

 direction: bassos have been known to take a on the great 

 octave (110 vibrations per second), and Mozart, at Parma, 

 heard a soprano sing a note of the extraordinarily high pitch 

 c on the fifth accented octave (4224 vibrations per second). 



Vowels are musical tones produced in the larynx and 

 modified by resonance of the air in the pharynx and mouth. 

 To get the broad, a sounds, as ah, the mouth is widely 

 opened and the lips drawn back; to get such vowels as 



State the uses of the muscles of the larynx. 



What is the ordinary range of the human voice? What notes 

 have celebrated singers taken beyond the ordinary highest and lowest 

 limits? 



What are vowels? Illustrate the influence of the shape given to 

 the mouth-cavity in the production of different vowels, 



