1088 



THE VOICE. 



[BOOK in. 



have certain inborn qualities which lighten the labours of the 

 nervous mechanism, it is the latter which is the real basis of 

 the artist's fame ; the former may be so slight or so abstruse as 

 to escape observation, and a larynx, the notes of which have 

 charmed the world, may yield through the laryngeal mirror a 

 picture of the most commonplace kind. 



That the build of the larynx is thus wholly subordinate to 

 the nervous mechanism is further illustrated by the fact that 

 the same larynx may and indeed does produce different kinds 

 of voice. The difference in the kind of voice which may be 

 brought about by the nervous system working the same larynx 

 in different ways is strikingly shewn by comparing what is 

 called the chest voice and the head voice. In the former, 

 which deals with relatively low notes, the sounds are full and 

 strong, and the lower resonance chamber which is supplied by 

 the trachea, bronchi and indeed by the whole chest, is thrown 

 into powerful and palpable vibrations ; hence the name 4 chest 

 voice.' The latter, which deals with relatively high notes, is 

 thin and poor, being deficient in partial tones, is not accom- 

 panied by the same conspicuous vibrations of the chest but is 

 accompanied by vibrations of the head ; hence the name 4 head 

 voice.' 



It is obvious that the dispositions of the larynx must be very 

 different in the two voices; but what the differences exactly 

 are has been and still is a matter of controversy, and indeed 

 extended laryngoscopic observation leads to the conclusion that 

 the change from the one voice to the other is not effected in 

 precisely the same way by all larynges. The evidence however 

 seems to shew that in the chest voice the vocal cords are rela- 

 tively broad and thick, and that the membranous glottis is 

 open along its whole length. The cords will of course vary as 

 to their tension through the range of the voice, being more 

 tense with the higher 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 



