100 OF THE VOICE AND SPEECH. 



154. The part of the larynx most concerned in pro- 

 ducing the voice, is the glottis, or narrow opening of 

 the windpipe, having the epiglottis suspended, and, in 

 a manner, fixed upon it. It is clearly ascertained, that 

 the air, expired from the lungs, and striking properly 

 upon the margins of the glottis, becomes sonorous. 



155. But it has been disputed what changes the 

 glottis undergoes in modulating the voice : whether it 

 is alternately widened and constricted, as Galen and 

 Dodart supposed, or whether, according to Ferrein, 

 the variations of voice are effected rather by the tension 

 and relaxation of its ligaments. 



The latter, consistently with his opinion, compared 

 the larynx to a violin ; the former, more consistently 

 with nature, to a flute.* 



Every thing considered, we must conclude that the 

 glottis, when sounding, experiences both kinds of 

 changes ; since the grave and acute modulation of the 

 voice must depend very much upon the alterations 

 produced in the glottis by the ligaments, especially the 

 inferior thyreo-arytenoids the vocal chords of Ferrein^ 

 and by the corresponding modification of the sinuses or 

 ventricles of the larynx.^ 



156. That every degree of motion in the glottis is 

 directed by the numerous muscles of the larynx, is 



* Kratzenstein viewed the glottis and larynx as a kind of drum, with its head 

 bisected. Tentamen de natiera ct charactere Sonorum Litterarum Vocaliwm. 

 Petrop. 1781. 4to. I would, in some sense, compare it to an Eolian harp, 

 particularly one of the description found by LabillardUire in Amboyna. Voyage 

 it fa Recherche de la Permise. T. i. p. 326. 



f See some experiments made at Gbttingen with the view of settling this 

 controversy, in J. G. Runge's Dissertation De Voce ejttsque Organis.. L. B. 

 1753. 4to. Also consult Jos. Ballanti, Commcntar. Institnti Banon. T. vi- 

 and Vicq.-d'Azyr, Mem. dc I'Mad. dcs Sc. d Paris, 1729., 



