204 M. Savart on the Mechanism of' the Human Voice. 



a cast of it by running into it plaster of Paris, and of this 

 cast Fig. 8 is an exact representation of the natural size, and 

 Fig. 9 a side view of it. The ventricles A A' sometimes rise 

 still higher than in the figure, and their summit touches the 

 fat body at the base of the epiglottis. I have seen two cases, 

 in which they were one Paris inch long from the bottom to 

 the summit. In general they are only half that height, viz. 

 5 or 6 lines. The intervals BB, Fig. 8 and 10, are filled by 

 the vocal ligaments, and the thyro-arytenoidian muscles, and 

 the intervals CC by the superior muscles. In the side view 

 Fig. 9, there is a better view of the extent of the fold of 

 the mucous membrane, which stretches from the epiglottis 

 to the corresponding arytenoid. This fold occupies the 

 space A ; BB' and terminates superiorly at the line AC. 

 Fig. 10 represents a section of the larynx on the line AL, 

 Fig. 9, dividing it into two parts. This figure gives a dis- 

 tinct idea of the interior form of the larynx, which has a very 

 great resemblance to the apparatus in Fig. 7. 

 . These facts being established, it becomes easy to explain 

 the formation of the human voice, by considering the vocal 

 organ as composed of the larynx Fig. 10, of the posterior 

 mouth, and of the mouth as a conical tube in which the air is 

 made to vibrate with a motion analogous to that in the 

 flute-pipes of organs. The vocal tube possesses all the pro- 

 perties that are necessary, in order that the mass of air which 

 it contains may be susceptible, in spite of its small volume, to 

 yield a sufficiently great number of sounds, and even very 

 grave ones. Its inferior part is formed with elastic sides, 

 which can assume all degrees of tension, while the mouth, by 

 opening more or less, and consequently changing the dimen- 

 sions of the column of air, exerts also a notable influence on 

 the number of vibrations conjointly with the lips, which, by 

 their approach and recession, transform at pleasure the vocal 

 tube into a conical tube, sometimes open and sometimes al- 

 most shut. 



It deserves to be remarked, that the sound of a conical 

 tube, slightly truncated at its summit, of the same capacity 

 nearly as the vocal tube of man, and of the same length, viz. 

 4 j inches, does not require to be much lowered, in order to 



