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strument, Mr. Dodart was the first who shewed the 

 glottis to be the chief organ in producing it, and con- 

 sidered it bjth as a string and wind instrumentj far 

 more perfect than any which art can produce. 



The organs which form the various voices of other 

 animals, are likewise worthy of our attention. Those 

 of each species have peculiar sounds, whereby they 

 understand each other. Wherein do these organs re- 

 semble ours ? and wherein do they differ ? 



The human voice is almost wholly formed by the 

 glottis, and various tunes are produced by the various 

 modifications of it. But all these depend on one only; 

 tbe separation and junction of its lips. This compre- 

 hends two circumstances, the one capital and primi- 

 tive, the other, a consequence of it. The first is, 

 That the lips are more and more bent, from the 

 lowest to the highest note. The second, That the 

 more they bend, the nearer they draw to each other. 

 It follows from the first, that their vibrations will 

 be more frequent, as they come nearer the highest 

 tone, and that the voice will be exact when they are 

 equaily bent, and the reverse when unequally : which 

 corresponds perfectly well with the nature of stringed 

 instruments. It follows from the second, that the 

 higher the tone, the nearer they draw to each other. 

 And this agrees perfectly with those wind-instruments' 

 which are governed by reeds. From these simple, and 

 almost imperceptible variations, proceeds the infinite 

 variety of sounds. 



In most quadrupeds too the glottis is the principal 

 organ of the voice. So it is in cats, sheep, and several 

 others. But many have something more than a glot- 

 tis. As horses, asses, mules, and swine;. Some of 

 these have also a tendinous membrane, which concurs 

 in forming the voice. Others have several membranes: 

 others a kind of bags, which in some are membra- 

 nous and in others bony. Others have both mem brines 

 and bags. Others, lastly, have in -their larynx a kind 

 of cavity or drum, which assists them in, uttering very 

 strong and long continued notes. ~ 

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