332 VOCAL APPARATUS. L.ECT. XVIII. 



LECTURE XVIII. 



VOCAL APPARATUS. THE VOICE. 



ARGUMENT. Description of the human vocal organ. Experiments demon- 

 strative of the seat and mechanism of the voice : structure of the vocal 

 cords. Analogies between the human voice and musical instruments. 

 Description of reed-instruments. The human vocal organ is a reed-in- 

 strument with membranous lips. Results of Muller's experiments on 

 the larynx. Qualities of the human voice. The human vocal organ is 

 infinitely superior to any musical instrument. Artificial caoutchouc, 

 larynx. 



AFTER the lectures on the nervous force and muscular 

 contraction, I must immediately proceed to the considera- 

 tion of the production of sound in animals; which here, as 

 in all other cases, is caused by a vibratory movement. In 

 the vocal organ this movement is produced by the contrac- 

 tion of muscles, and of parts subjected to their influence, 

 and from them, therefore, the voice takes its origin. 



Organ of Voice in Man. In order that I may be enabled 

 to explain at sufficient length, the theory of the vocal organ 

 of man and animals, I must not pass over in silence the de- 

 scription of its constituent parts. It is easy to prove, ex- 

 perimentally, the position occupied by this apparatus. A 

 very superficial examination shows us that the voice is pro- 

 duced when air is expelled from the lungs ; and every one 

 knows that it is impossible to articulate sounds when we 

 close the mouth and nose. It is, therefore, evident, that 

 the vocal organ resides in a certain portion of the tube which 



