MECHANISM OF VOICE. 233 



The vocal apparatus of man is composed of the lungs, 

 acting as a bellows; the trachea, which conducts the air from 

 the lungs to the larynx, where the sound is formed; and of 

 the pharynx, the buccal, and nasal cavities, which increase 

 the sounds and modify their character. 



The air driven through the glottis by the lungs causes a 

 vibration of the vocal cords, and sound is produced; it is 

 increased by passing through the upper part of the larynx, 

 the mouth, and nasal fossae; it acquires more or less volume, 

 and its character varies according as these cavities are more 

 or less open and free; but it does not change its nature as 

 regards the tone. If, for example, the glottis emits a C, 

 it may be heard as a muffled, a natural, or a nasal sound, 

 according to the condition in which the cavities are through 

 which it passes; but the tone does not change, it is always 

 aC. 



Savants have held different opinions on the formation of 

 sounds in the larynx, and upon the functions of the constitu- 

 ent parts of the vocal organs. It being impossible to con- 

 sider all these opinions, or the many experiments which have 

 been made, the physical laws upon which they were founded, 

 or which were opposed to them, we shall confine ourselves 

 to a summary explanation of a few of them. 



We may be permitted, however, first to quote from the 

 Magasin Pittoresque an anecdote which very well illustrates 

 this point of our subject: 



In 1798 Cuvier, in reading an essay on the voices of birds 

 before the Academy of Sciences, remarked that some phy- 

 siologists considered the larynx as a stringed instrument, 

 others as a wind-instrument. An academician spoke and 

 denied this distinction, affirming that everybody knew that 

 the larynx was a wind-instrument. "You are in error," im- 

 mediately exclaimed another member, "it is a stringed in- 

 strument." 



These two theories have long divided philosophers. 



Galen looked upon the glottis as a reed; Fabricius Acqua- 

 pendente gave a remarkable description of the larynx in the 

 sixteenth century; he recognized the glottis as the essential 

 organ of the voice, and compared its action to that of an 



