CHAP. VIL] SPECIAL MUSCULAR MECHANISMS. 1467 



to the man who could not sing ; for the power to sing is determined 

 not by the build of the larynx but by the possession of an adequate 

 nervous mechanism through which finely appreciated auditory 

 impulses are enabled so to guide the impulses of the will that 

 these find their way with sureness and precision to the appropriate 

 muscular bundles. And what is true of the difference between 

 singing and not singing at all is in a similar way true of the 

 difference between singing low and singing high, as well as of 

 the difference between singing superbly and singing indifferently 

 well. The physiological difference between a bass voice and a 

 tenor voice, between a contralto and a soprano probably lies not 

 so much in the mere natural length of the vocal cords as in the 

 constitution of the nervous and muscular mechanism ; experience 

 shews that cords of the same natural length may in one individual 

 be the instrument of a bass, in another of a tenor voice, or in one 

 individual of a contralto, in another of a soprano voice. Again, 

 though the " magnificent organ " of a distinguished artist may 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 ' chest voice.' The latter, which deals with rela- 

 tively high notes, is thin and poor, being deficient in partial tones, 

 is not accompanied by the same conspicuous vibrations of the chest 

 but is accompanied by vibrations of the. head ; hence the name 

 ' 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 relatively 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 



