PRODUCTION OF THtf VOICE. 497 



of rendering the vocal chords rigid and increasing the in- 

 tensity of their vibrations. 1 The great variations that may 

 be produced in the pitch and quality of the voice by the 

 action of muscles operating directly or indirectly on the 

 vocal chords render the problem of determining the precise 

 mode of action of the intrinsic muscles of the larynx exceed- 

 ingly complicated and difficult. It is certain, however, that, 

 in these muscular acts, the thyro-arytenoids play an impor- 

 tant part. Their contraction regulates the thickness and 

 rigidity of the vocal chords, while at the same time it modi- 

 fies their tension. Fournie regards the swelling of the chords, 

 which may be rendered regular and progressive under the 

 influence of the will, as one of the most important agents in 

 the formation of the tones of the voice. 3 



Mechanism of the Production of the Voice. 



It will save much unprofitable discussion to dismiss 

 quite briefly most of the theories that have been advanced 

 to explain the production of the voice, and to avoid com- 

 parisons of the larynx with different kinds of musical instru- 

 ments. Before the larynx had been studied in action by 

 means of the laryngoscope, physiologists, having the anatom- 

 ical structure of the parts for their only guide, presented 

 various speculations with regard to the mechanism of phona- 

 tion, which were frequently utterly opposed to each other in 

 principle. The vocal apparatus was compared to wind or 

 brass instruments, to reed-instruments, to string-instruments, 

 to the flute, etc., and some even refused to the vocal chords 

 any share in the sonorous vibrations. An apparatus was de- 

 vised to imitate the vocal organs, experiments were made with 

 the larynx removed from the body, and every thing seemed 

 to be done, except to observe the organs in actual function. 3 



1 LONGET, op. cit., p. 730. 



2 FOURNIE, Physiologic de la voix et de la parole, Paris, 1866, p. 121. 



3 Perhaps the most elaborate of the observations made before the discovery 

 of the laryngoscope are those of J. Miiller, who experimented very extensively 



32 



