VOCAL IMITATION, AND VENTRILOQUISM. 



255 



the upper part of it, or that immediately connected with the liyoid-bone, the 

 larynx : and it is this upper part or larynx alone that constitutes the seat 

 of the voice. 



The tube of the larynx, short as it is, is formed of five distinct cartilages; the 

 largest, and apparently, though not really, lowermost of which, produces that 

 acute projection or knot in the anterior part of the neck, and especially in the 

 neck of males, of which every one must be sensible. This is not a complete 

 ring, but is open behind ; the open space being filled up, in order to make a 

 complete ring, with two other cartilages of a smaller size and power; and 

 which together form the glottis, as it is called, or aperture out of the mouth 

 into the larynx. The fourth cartilage lies immediately over this aperture, 

 and closes it in the act of swallowing, so as to direct the food to the esopha- 

 gus, another opening immediately behind it, which leads to the stomach. 

 These four cartilages are supported by a fifth, which constitutes their basis ; 

 is narrow before, and broad behind, and has some*resemblance to a seal-ring. 

 The larynx is contracted and dilated in a variety of ways by the antagonist 

 power of different muscles, and the elasticity of its cartilaginous coats; 

 and is covered internally with a very sensible, vascular, and mucous mem- 

 brane, which is a continuation of the membrane of the mouth. 



The organ of the voice then is the larynx, its muscles, and other append- 

 ages ; and the voice itself is the sound of the air propelled through and 

 striking against the sides of its glottis, or opening into the mouth. The 

 shrillness or roughness of the voice depends on the internal diameter of the 

 glottis, its elasticity, mobility, and lubricity, and the force with which the air 

 is protruded. Speech is the modification of the voice into distinct articula- 

 tions, in the cavity of the glottis itself, or in that of the mouth, or of the nostrils. 



Those animals only that possess lungs possess a larynx, and hence none 

 but the first three classes in the Linnsean system, consisting of mammals, 

 birds, and amphibials. Even among these, however, some genera or species 

 are entirely dumb, as the myrmecophaga or ant-eater, the manis or pangolin, 

 and the cetaceous tribes, together with the tortoise, lizards, and serpents ; 

 while others lose their voice in particular regions : as the dog is said to do in 

 some parts of America,* and quails and frogs in various districts of Siberia.f 



It is from the greater or less degree of perfection with which the larynx is 

 formed in the different classes of animals that possess it, that the voice is 

 rendered more or less perfect ; and it is by an introduction of superadded 

 membranes, or muscles, into its general structure, or a variation in the shape, 

 position, or elasticity of those that are common to it, that quadrupeds and 

 other animals are capable of making those peculiar sounds, by which their 

 different kinds are respectively characterized, and are able to neigh, bray, 

 bark, or roar ; to purr as the cat and tiger kind, to bleat as the sheep, or to 

 croak as the frog. 



The larynx of the bird class is of a very peculiar form, and admirably 

 adapted to that sweet and varied music with which we are so often delighted 

 in the woodlands. In reality, the whole extent of the trachea or windpipe in 

 birds may be regarded as one vocal apparatus ; for the larynx is divided into 

 two sections, or may rather, perliaps, be considered as two distinct organs ; 

 the more complicated, or that in which the parts are more numerous and 

 elaborate, being placed at the bottom of the trachea, where it divides into two 

 branches, one for each of the lungs; and the simpler, or that in which the 

 parts are fewer, and consist of those not included in the former, occupying its 

 usual situation at the upper end of the trachea, which, however, is without an 

 epiglottis ; the food and other substances being incapable of entering the 

 aperture of the glottis from another contrivance. The lungs, trachea, and 

 larynx of birds, therefore, may be regarded as forming a complete natural 

 bagpipe ; in which the lungs constitute the pouch and supply the wind ; the 

 trachea itself the pipe ; the inferior glottis the reed, or mouth-piece, which 

 produces the simple sound ; and the superior glottis the finger-holes, which 



* Pennant, Arctic Zool. 



t Muller, Collect, of Russian Discoveries, vol. vii. p. 123. 



