440 VOICE. [CHAP. XXXT. 



active supporters of the explanation of the formation of voice, on 

 the principle of wind-instruments. He likened the larynx to a 

 bird-call, and referred the exact seat of the development of sound 

 to the air contained in the ventricles of the larynx, which would 

 be affected by the upward current from the trachea, just as the air 

 in the cavity of the bird-call is by the current from the mouth. 

 But, to pass over the argument, that it is very doubtful whether 

 the bird-call can be referred exclusively to the class of wind-instru- 

 ments, M. Savart's views are decidedly negatived, by the fact that 

 in the class of ruminants the superior or false vocal ligaments are 

 absent, and, consequently, the ventricle of the larynx. 



Ferrein was the first to show by experiment, that vibration of 

 the vocal chords was the essential cause of voice. His experiments, 

 published in 1741, were performed on the dead larynx. By them 

 he was enabled to show, that the note varied according to the 

 length and tension of the vocal chords, the same laws regulating 

 the production of sound by these chords as by strings which are 

 thrown into sonorous vibrations by currents of air. 



The most important experiments upon the production of vocal 

 sounds are those of Professor J. Miiller of Berlin, and of Professor 

 Willis of Cambridge. Miiller investigated the action of mem- 

 branous bands, or of tongues formed of caoutchouc, in generating 

 sound under the influence of a current of air. The human organ 

 of voice is imitated by a tube, capable of being varied in length ; 

 to one end of this are applied two membranous vibrating tongues, 

 attached to the wall of the tube, but separated from each other by 

 a chink, through which passes the current of air necessary for 

 throwing them into sonorous vibrations. Willis employed a similar 

 instrument. 



The results of these experiments may be thus briefly stated 



1st. That elastic bands, forming the lateral boundaries of a chink, 

 through which a current of air is driven by a pair of bellows, may 

 be thrown into vibrations so as to produce sounds which resemble 

 those of the human voice. 



2nd. That for such vocalization it is necessary that these bands 

 should have, in addition to a certain degree of tension, a particular 

 position likewise. This, which is called by Willis the vocalizing 

 position, consists in the parallelism of the margins of the bands. 

 In the quiescent state, during breathing, the lips of the glottis are 

 inclined from each other ; but in the vocalizing position, or that 

 necessary for the production of voice, they become parallel. In 

 the former condition, the glottis is a triangular space, with divergent 



