468 MUSCULAR MOTION. 



although we may conceive, that the larynx can produce voice and vary 

 its tones, in the manner of a reed instrument, we are unable to demon- 

 strate the particulars of its mode of action. 



All the more modern theories detailed above, at more or less length 

 agree, then, in considering the larynx to be a wind instrument of the 

 reed kind: they differ, chiefly, in the role which they assign to the 

 vocal tube in causing the variation of tones. 



M. Savart 1 has propounded a theory of voice, in which he differs from 

 MM. Cuvier, Dutrochet, and Magendie. He denies, that the mechanism 

 of the voice resembles that of the reed instrument, and returns to the 

 old idea, which referred the vocal organ to an instrument of the flute 

 kind. The sounds of the human voice have, he remarks, a peculiar 

 character, which no musical instrument can imitate; and this must 

 necessarily be the case, as they are produced by a mechanism founded 

 on principles which do not serve as a basis in the construction of any of 

 our instruments. He conceives that the production of the voice is 

 analogous to that of the sound in the tube of a flute; and that the 

 small column of air, contained in the larynx and mouth, by the nature 

 of the elastic parietes which bound them, as well as by the mode in 

 which it is thrown into vibrations, is susceptible of rendering sounds of 

 a particular nature, and, at the same time, much more grave than the 

 dimensions would seem to permit. 



In the tube of a flute, the column of air within is the sonorous body. 

 A sound is first produced at the embouchure of the .instrument, by the 

 division which the air experiences when blown in; and this excites similar 

 sonorous undulations in the column of air that fills the tube. The 

 sound, resulting in this way, is grave in proportion to the length of the 

 tube; and in order to vary its tones, the instrument has apertures -in 

 its sides, by means of which its length may be modified. 



In assimilating the human vocal apparatus to a flute, the great diffi- 

 culty has been to explain how, with so short a tube as the vocal tube 

 in man, and one so little variable in length, tones so different, and 

 especially so grave, can be produced. To account for this, M. Savart 

 establishes a number of physical facts, previously unknown or unno- 

 ticed. In organ-pipes of great length, the velocity of the current of 

 air, which acts as a motor, has but little influence on the number of 

 oscillations. When the length of the pipe, for instance, is twelve or fif- 

 teen times greater than its diameter, it is difficult to vary the sound a 

 semitone. When air is forcibly driven in, it rises an octave; and, 

 when its velocity is diminished, the sound becomes more feeble; but is 

 depressed an almost imperceptible quantity. In short pipes, on the 

 contrary, the influence of the velocity of the current of air is much 

 greater, and several tones can be elicited. The bird- 

 call used by sportsmen is illustrative of this principle. 

 It is a small instrument, employed for imitating the 

 notes of certain birds, and consists of a cylindrical tube, 

 about three-fourths of an inch in diameter, and a third 



of an inch hi S n ; closed at each end b J a thin > flat P late > 



1 Journal de Physiologic, v. 367, Paris, 1825; and Annales de Physique et de Chimie, 

 xxx. 64, and xxxii. 



