CHAPTER XXXVIII. 

 VOICE AND SPEECH. 



Voice consists of sounds produced by the vibrations of 

 two elastic bands, the true vocal cords, placed in the larynx, 

 an upper modified portion of the passage which leads from the 

 pharynx to the lungs. When the vocal cords are put in a cer- 

 tain position, air driven past them sets them in periodic vibra- 

 tion, and they emit a musical note; the lungs and respiratory 

 muscles are, therefore, accessory parts of the vocal apparatus : 

 the strength of the blast produced by them determines the 

 loudness of the voice. The larynx itself is the essential voice- 

 organ: its size primarily determines the pitch of the voice, 

 which is lower the longer the vocal cords; and, hence, shrill 

 in children, and usually higher pitched in women than in 

 men: the male larynx grows rapidly at commencing man- 

 hood, causing the change commonly known as the " breaking 

 of the voice." Every voice, while its general pitch is de- 

 pendent on the length of the vocal cords, has, however, a 

 certain range, within limits which determine whether it shall 

 be soprano, mezzo-soprano, alto, tenor, baritone, or bass. 

 This variety is produced by muscles within the larynx which 

 alter the tension of the vocal cords. Those characters of 

 voice which we express by such phrases as harsh, sweet, or 

 sympathetic, depend on the structure of the vocal cords of 

 the individual; cords which in vibrating emit only harmonic 

 partial tones (Chap. XXXV) are pleasant; while those in 

 which inharmonic partials are conspicuous are disagreeable. 



The vocal cords alone would produce but feeble sounds; 

 those that they emit are strengthened by sympathetic reso- 

 nance of the air in the pharynx and mouth, the action of 

 which may be compared to that of the sounding-board of a 

 violin. By movements of throat, soft palate, tongue, cheeks, 

 and lips the sounds emitted from the larynx are altered or 



