WHISTLING. 237 



mation of sounds in the glottis includes that faculty which 

 man possesses of producing the sounds of whistling. This 

 .is certainly a much less important and less elevated function; 

 but it is nevertheless very interesting to the physiologist, as 

 it evidently nearly resembles that of the voice in its me- 

 chanism. 



In order to produce the sound of whistling, the lips form 

 a real glottis, which Dodart has named the labial glottis. The 

 opening between the lips varies in form; in the grave tones it 

 is nearly round in shape, and at its maximum in diameter ; in 

 the acute sounds it becomes elliptic, and is reduced to a 

 narrow slit; the tongue regulates the intonation, by approach- 

 ing more or less to the lower front teeth, touching them in 

 the acute sounds, and withdrawing itself in the grave sounds. 

 The space which separates the lips from the teeth varies also, 

 in the same relative degree, for the same reason. The tongue 

 sharpens the notes as in flute-playing; the grave sounds may 

 be produced in drawing in the air, as in breathing; in short, 

 the sound is acute or intense in proportion to the impulsion 

 of the air by the lungs. 



If a disk of cork be placed between the lips, about one- 

 fifth of an inch in thickness, with a hole about one line 

 in diameter in the centre, the sound of whistling can be pro- 

 duced through this aperture, and modulated the same as 

 with the lips. Cagniard de la Tour, to whom we are in- 

 debted for this experiment, concludes from it that the sound 

 does not proceed from the vibrations of the lips; but has its 

 origin in those of the air, excited by an intermittent friction 

 against their walls. Longet and Masson compare the appar- 

 atus for whistling in man to the whistle of a bird-catcher, and 

 they find a close analogy between the labial and the laryngeal 

 glottis. 



Fournie' rejects this theory, and supposes the sound of 

 whistling to be produced by mechanism analogous to that of 

 an organ-pipe, the air breaking against the stop, which is 

 represented by the upper incisors. Whichever doctrine we 

 may accept, it is certain that the lips, or the perforated disk 

 which replaces them, play an important part in the produc- 

 tion and modification of sound in ordinary whistling, for 



