504- 



VOICE AND SPEECH. 



Above the pile of cartilaginous rings which compose the wind- 

 pipe is placed the cricoid cartilage ; the thyroid cartilage embraces 

 the cricoid, and is articulated to its sides so that its lower horn 

 turns round on a point as a fulcrum. Two small cartilages 

 called the arytenoids are articulated to the upper external 

 edge of the cricoid, and the vocal ligaments are stretched from 

 the thyroid to the arytenoids. The aperture between the edges 



Bird's-eye view of the larynx from above. 



G E H, thyroid cartilage, embracing 

 the ring of the cricoid r u X w, and 

 capable of turning on the axis x z, 

 which passes through the lower 

 horns C, seen in the preceeding 

 figure ; 



N F, N F, the arytenoid cartilages ; 



T V, T V, the vocal ligaments. 



From N to X run the right lateral 

 crico-arytenoid muscle, the left 

 having been removed. 



of the vocal ligaments is called the glottis ; and in all the theo- 

 ries which have been advanced it has been admitted that the 

 vocal sound is produced by the breath passing through this 

 aperture, though different explanations have been offered of the 

 way in which the voice is produced. Ferrein compared the vocal 

 ligaments to violin strings, and the current of air which puts 

 them in motion to a violin bow ; the different sounds he attri- 

 buted to various tensions of the ligaments. Dodart found an 

 analogy between the glottis and the embouchure of a flute ; the 

 pitch of the sound he supposed to depend on the size of the 

 aperture. Biot thought the way in which the sound of the voice 

 was produced more analogous to a reed, and particularly to that 

 kind of reed which has but lately been introduced into a variety 

 of musical instruments, Savart has lately endeavoured to prove 

 that the sounds of the voice are produced in the same manner 

 as in a lark-whistle, and that the pitch depends on altering the 

 tension of the elastic sides of the small conical tube formed by 

 the part of the larynx immediately before this aperture. 



There can be no doubt as to the way in which the sonorous 

 vibrations are produced in the larynx. If a piece of silk riband. 



