THE VOICE AND SPEECH. 55 



of the vocal cord under different circumstances. Thus, in ordinary tran- 

 quil breathing, the opening of the glottis is wide and triangular (B) 

 becoming a little wider at each inspiration, and a little narrower at each 

 expiration. On making a rapid and deep inspiration the opening of the 

 glottis is widely dilated (as in c), and somewhat lozenge-shaped. At the 

 moment of the emission of sound, it is narrowed, the margins of the 

 urytenoid cartilages being brought into contact and the edges of the vocal 

 cords approximated and made parallel, at the same time that their tension 

 is much increased. The higher the note produced, the tenser do the 

 cords become (Fig. 298, A) ; and the range of a voice depends, of course, 



FIG. 299. View of the larynx and part of the trachea from behind, with the muscles dissected; 

 ft, the body of the hyoid bone; e, epiglottis; f, the posterior borders of the thyroid cartilage; c, the 

 median ridge of the cricoid; a, upper part of the arytenoid; s, placed on one or the oblique fasciculi 

 of the arytenoid muscle ; 6, left posterior crico-arytenoid muscle ; ends of the incomplete c'artilagi- 

 nous rings of the trachea; I, fibrous membrane crossing the back of the trachea; n, muscular fibres 

 exposed in a part (from Quain's Anatomy). 



in the main, on the extent to which the degree of tension of the vocal 

 cords can be thus altered. In the production of a high note, the vocal 

 cords are brought well within sight, so as to be plainly visible with the 

 help of the laryngoscope. In the utterance of grave tones, on the other 

 hand, the epiglottis is depressed and brought over them, and the arytenoid 

 cartilages look as if they were trying to hide themselves under it (Fig. 

 391). The epiglottis, by being somewhat pressed down so as to cover the 

 superior cavity of the larynx, serves to render the notes deeper in tone, 

 and at the same time somewhat duller, just as covering the end of a 

 short tube placed in front of caoutchouc tongues lowers the tone. In 

 no other respect does the epiglottis appear to have any effect in modify- 

 ing the vocal sounds. 



