THE VOICE. 391 



so-called vocal chords or vocal ligaments. During respi- 

 ration the vocal chords are quite slack, the glottis is 

 rather wide, and a current of air passing through it 

 produces no sound; but in speaking and singing the 

 vocal ligaments are tightened by the action of the 

 muscles of the larynx, their edges are close together, 

 and the air, as in a reed-pipe, is compelled to force a 

 passage for itself between them; they are thus made to 

 vibrate, and a periodically interrupted current of air, 

 that is, a series of impulses, is produced. Although the 

 vocal chords are soft, indeed much softer than the 

 elastic plates of mouth instruments, their action, espe- 

 cially when they are stretched, is rather that of metal 

 tongues than that of soft plates, for their elasticity, and 

 consequently the pitch of the notes produced, does not 

 depend on the length of the aerial column before them 

 (that in the cavity of the mouth), but upon their ten- 

 sion: the note will be high or low according as the 

 vocal chords are tightened or relaxed. If the larynx 

 be removed from the body and air be blown through 

 it by a pair of bellows, sound is produced, and the 

 pitch may be varied by varying the tension of the 

 vocal chords. The quality of the sound emitted re- 

 sembles that of a reed pipe, but the human voice re- 

 ceives its peculiar quality from a variety of accidental 

 circumstances: it depends upon the formation of each 

 particular larynx, the primitive length of its vocal 

 chords, their elasticity, the amount of resonance of the 

 surrounding parts, and so on. 



Speech is voice modulated by the throat, tongue, and 

 lips, and the modulation is effected by changing the 

 form of the cavity of the mouth and nose by the action 



