558 OF THE VOICE AND SPEECH. 



the cartilages are harder, and are sometimes almost completely ossified. 

 The loudness of the voice depends in part upon the force with which 

 the air is expelled from the lungs ; but the variations in this respect 

 which exist among different individuals, seem partly due to the degree 

 in which its resonance is increased by the vibration of the other parts 

 of the larynx, and of the neighbouring cavities. In the Howling 

 Monkeys of America, there are several pouches opening from the 

 larynx, which seem destined to increase the volume of tone that issues 

 from it ; one of these is excavated in the substance of the hyoid bone 

 itself. Although these Monkeys are of inconsiderable size, yet their 

 voices are louder than the roaring of lions, and are distinctly audible at 

 the distance of two miles ; and when a number of them are congregated 

 together, the effect is terrific. 



980. The vocal sounds produced by the action of the larynx are of 

 very different characters ; and may be distinguished into the cry, the 

 song, and the ordinary or acquired voice. The cry is generally a sharp 

 sound, having little modulation or accuracy of pitch, and being usually 

 disagreeable in its timbre or quality. It is that by which animals 

 express their unpleasing emotions, especially pain or terror ; and the 

 Human infant, like many of the lower animals, can utter no other 

 sound. In song, by the regulation of the vocal cords, definite and sus- 

 tained musical tones are produced, which can be changed or modulated 

 at the will of the individual. Different species of Birds have their 

 respective songs ; which are partly instinctive, and partly acquired by 

 education. In Man, the power of song is entirely acquired ; but some 

 individuals possess a much greater facility in acquiring it than others, 

 this superiority appearing to depend upon their more precise con- 

 ception of the tones to be sounded, as well as their more ready imitation, 

 besides differences in the construction of the larynx itself. The 

 larynx of an accomplished vocalist, obedient to the expression of the 

 emotions, as well as to the dictates of the will, may be said to be the 

 most perfect musical instrument ever constructed. The voice is a sound 

 more resembling the cry, in regard to the absence of any sustained 

 musical tone ; but it differs from the cry, both in the quality of its 

 tone, and in the modulation of which it is capable by the will. In 

 ordinary conversation, the voice passes through a great variety of 

 musical tones, in the course of a single sentence, or even a single word, 

 sliding imperceptibly from one to another ; and it is when we attempt 

 to fix it definitely to a certain pitch, that we change it from the speak- 

 ing to the singing tone. 



981. The power of producing articulate sounds, from the combination 

 of which Speech results, is altogether independent of the Larynx ; being 

 due to the action of the muscles of the niQuth, tongue and palate. 

 Distinctly-articulate sounds may be produced without any vocal or 

 laryngeal tone, as when we whisper; and it has been experimentally 

 shown, that the only condition necessary for this mode of speech is the 

 propulsion of a current of air through the mouth, from back to front. 

 On the other hand, we may have the most perfect laryngeal tone without 

 any articulation ; as in the production of musical sounds, not connected 

 with words. But in ordinary speech, the laryngeal tone is modified by 



