PRODUCTION OF VOCAL SOUNDS. 



613 



have the same tension ; only with a wide aperture, the 

 tone is more difficult to produce, and is less perfect, the 

 rushing of the air through 

 the aperture being heard at 

 the same time. 



No true vocal sound is pro- 

 duced at the posterior part 

 of the aperture of the glottis, 

 that, viz., which is formed by 

 the space between the ary- 

 tenoid cartilages. For, as 

 Miiller's experiments showed, 

 if the arytenoid cartilages 

 be approximated in such a 

 manner that their anterior processes touch each other, but 

 yet leave an opening behind them as well as in front, no 

 second vocal tone is pro- pig m ^^j 



duced by the passage of * 



the air through the pos- 

 terior opening, but merely 

 a rustling or bubbling 

 sound ; and the height or 

 pitch of the note produced 

 is the same whether the posterior part of the glottis be 

 open or not, provided the vocal cords maintain the same 

 degree of tension. 



* Fig. 174. View of the anterior of larynx from above, i, aperture 

 of glottis ; 2, arytenoid cartilages ; 3, vocal cords ; 4, posterior crico- 

 arytenoid muscles ; 5, lateral crico-arytenoid muscle of right side, that 

 of left side removed ; 6, arytenoid muscle ; 7, thyro-arytenoid muscle 

 of left side, that of right side removed ; 8, thyroid cartilage ; 9, cricoid 

 cartilage ; 13, posterior crico-arytenoid ligament. "With the exception 

 of the arytenoid muscle, this diagram is a copy from Mr. "Willis's figure. 



f Fig. 175. VieAV of the upper part of the larynx as seen by means of 

 the laryngoscope during the utterance of a grave note, c, epiglottis ; s, 

 tubercles of the cartilages of Santorini ; a, arytenoid cartilages ; z, base 

 of the tongue ; p7i, the posterior wall of the pharynx. 



