LARYNX AND PEON AT ION. 359 



octaves, and according to whether these two octaves belong 

 to the upper or lower part of the scale of musical sounds, the 

 human voice has been classified, beginning with the lowest, 

 into the bass voice (from fa to re 3 ), the barytone (from la to 

 fa a ), the tenor (from do 2 to Ia 3 ), the contralto (from mi 2 to 

 do 4 ), the mezzo-soprano (from so! 2 to mi 4 ), and the soprano 

 (from si 2 to so! 4 ), the three latter being women's voices. The 

 differences between them are principally owing to variations 

 in the length of the lips of the glottis ; this length is repre- 

 sented in man by the number 25, in woman by 20, and by 15 

 in eunuchs, their voice being extremely high. 



A child's voice is very high, the glottis being smaller than 

 that of the adult. The change in the voice takes place at 

 the age of puberty, the development of the larynx causing 

 the voice to become an octave lower in the case of boys, and 

 two notes only in that of girls. In old age, the ossification 

 of the cartilages, and the atrophy of the muscular fibres (?) 

 cause the voice to become still lower, while its intensity is 

 also diminished; thus tenors become barytones (L. Mandl). 



The tone of the voice is first produced by the lips of the 

 glottis itself. Helmholtz has, we know, demonstrated that 

 the tone (see Organs of the Senses, Hearing) is due to the 

 fact that the sounds which appear to us so simple are really 

 composed of a fundamental note, and several accessory 

 netes, called harmonics (Sauveur). The varied combina- 

 tion of these harmonic notes, in different instruments, con- 

 stitutes their special tone. The vocal lips, like the membranous 

 pipes, beside the fundamental vibration of one sound, exhibit 

 partial vibrations which give rise to various harmonics of this 

 note : whence the different tones of the note produced by 

 the glottis. What, however, especially marks the tone of 

 the voice, is the manner in which these harmonic notes are 

 reinforced in the cavities and vibrating edges above the 

 glottis (the pharynx, mouth, nasal chambers, etc.), so as to 

 impress their peculiar features upon the voice (see p. 357). 



By studying these harmonic notes as being the means by 

 which the tone of the voice is produced, Willis, Wheatstone, 

 Bonders, Du Bois-Reymond, and especially Helmholtz, 1 have 



1 See Helmholtz, " Theorie Physiologique de la Musique." 

 Trad. fran. par Gueroult, Paris, 1868. 



Langel, " La Voix, POreille, et la Musique." D'apres lea 

 travaux de Helmholtz. In " Revue des Deux-Mondes." Mai, 

 1867. 



