THE VOICE. 



597 



of muscles making up the sphincter of the larynx is contracted 

 when the inferior laryngeal is stimulated. 



Superior Face. Inferior Face, 



Fig. 436. — Cartilaginous pieces of tlie larynx of horsQ, maintained in their natural 

 position by the articular ligaments (Chaaveau), a, cricoid cartilage; b, b, aryte- 

 noid cartilages; c, body of the thyroid; c', c', lateral plates of the tfiyroid; d, epi- 

 glottis; e, body of the nyoid; /, trachea. 1, crico-arytenoid articulation; 2, capsule 

 of the crico-thyroid articulation; 3, crico- thyroid membrane; 4, thyro-hyoid mem- 

 brane; 5, crico-trachealis ligament. 



Above the true vocal bands composed of elastic fibers lie the 

 so-called false vocal bands (cords) to be regarded as folds of the 

 mucous membrane which take no essential part in voice-produc- 

 tion. Between these two pairs of bands are the ventricles of 

 Morgagni, which, as well as the adjacent parts, secrete mucus 

 and allow of the movements of both sets of bands and in so far 

 only assist in phonation. 



The whole of the supra-laryngeal cavities, the trachea and 

 bronchial tubes, may be regarded as resonance-chambers, the 

 former of which are of the most importance, so far as the 

 quality of the voice is concerned. There seems to be little 

 doubt that they have much to do with determining the differ- 

 ences by which one individual's voice at the same pitch differs 

 from another ; nor is the view that they may have a slight in- 

 fluence on the pitch of the voice, or even its intensity, to be 

 ignored. 



