Mechanism of the Larynx. 349 



the mesial plane are directed so as to draw the arytenoid towards B; but 

 this is counteracted by the fibres that lie farthest from the mesial plane ; 

 and as we may assume that the whole of the fibres of the muscle act at 

 once, the resultant of their action will be found as nearly as possible 

 perpendicular to the axis of articulation OP. 



A T ote D.—Page 336. 

 It is worth while to ascertain the state of tension of the vocal ligaments 

 when at rest, which we may readily infer from the application of the test 

 here described. If the finger be lodged in the space ED, Fig. 2, and a 

 bass note sounded, the larynx will descend from its position of rest, and 

 ED be enlarged ; if a high note be sounded, the larynx will ascend from 

 its usual position, and the space ED be diminished ; but an intermediate 

 note may be found, the sounding of which will not remove the larynx from 

 its ordinary position of rest, or alter the usual magnitude of ED, and this 

 note will be the average pitch of ordinary speech. Now, as I have shewn 

 that the space ED indicates the tension of the vocal ligaments, I infer 

 from this that in the position of rest these ligaments possess the tension 

 required for the average pitch of speech, requiring to be relaxed for deeper 

 notes, and stretched for higher. But as in this state of tension the breath 

 passes between them without being able to elicit vibrations from them, we 

 see the necessity of some such conditions as those I have described to 

 enable sounds to be produced at pleasure. 



Note E.—Page 338. 

 Some of the fibres of the arytenoideus transversus are attached to the 

 cricoid at one extremity, and are sometimes described as distinct muscles 

 under the name of arytenoidei obliqui ; they conspire with the transverse 

 fibres in drawing together the hinder portion of the arytenoids, and by 

 their oblique direction assist the cricoarytenoidei laterales in depressing the 

 arytenoids. 



