330 THE VOICE. [BOOK ITT. 



notes, and the width of the glottis is not always the same ; but it 

 is probable that throughout the voice the cords, in producing the 

 fundamental tone of any note sung, vibrate along their whole length, 

 and also through their whole breadth, the partial tones being due 

 of course, as in other musical instruments, to vibrations of segments. 

 In order to throw into vibration along their whole length such 

 relatively broad and thick cords a powerful blast of air is needed, 

 and hence the transmission of the vibrations downwards to the 

 chest. 



When the same larynx shifts to the head voice the vocal cords 

 appear to become narrow, thin and always distinctly tense. In 

 some cases the membranous glottis is closed before and behind, 

 so that the cords are free to vibrate in their middle portion only, 

 and here the slit is sometimes a relatively wide elliptical space ; 

 in other cases the glottis seems to be open along its whole extent, 

 though reduced to a mere linear slit; but it is probable that in 

 all cases the cords vibrate along a part only and not along the 

 whole of their length. In order to throw into adequate vibrations 

 the thin edges now presented, a less powerful blast is required, 

 and the vibrations are no longer felt in the chest, though they are 

 transmitted through the pharyngeal passages to the head. 



As subsidiary conditions we may mention that in the chest 

 voice the superior aperture of the larynx is widely open, the 

 transverse diameter being perhaps especially long, while in the 

 head voice the aperture is constricted, at times remarkably so. 

 In the chest voice the epiglottis is usually depressed so as to hide 

 from sight, in the laryngoscopic view, the front part of the cords, 

 while in the head voice it is usually raised, but many variations in 

 the attitude of the epiglottis may be observed. In the head voice 

 the cartilaginous glottis seems always to be completely closed, 

 whereas in the chest voice it is found in some cases to be closed, in 

 other cases to be more or less open. 



Making all allowance for discordance of opinion as to what are 

 the exact conditions of each kind of voice, and admitting the 

 imperfection of our knowledge as to both the purpose and the 

 mode of production of many of the differences observed, we may 

 at least draw the conclusion that in the case of each kind of voice 

 a certain general disposition of the mechanism is made, that a certain 

 ' setting ' of the machine takes place, by which the quality of the 

 voice is determined, and that the machine thus set is played upon 

 so as to produce a series of notes differing in pitch but all retaining 

 the same particular quality. The setting of the machine in the 

 chest voice is such that the notes produced by it are lower notes 

 reaching up to a certain pitch only, the setting not being adapted 

 for higher notes, and conversely the setting of the head voice 

 allows of the production of high notes only, being incompatible 

 with the production of low notes. 



It may be urged that the setting for the chest voice is really 



