558 VOICE AND SPEECH. 



Coming to the larynx itself, we find that the capacity of its cavity is capable of certain 

 variations. In fact, both the vertical and the bilateral diameters are diminished in high 

 notes and are increased in low notes. The vertical diameter may be modified slightly 

 by ascent and descent of the true vocal chords, and the lateral diameter may be reduced 

 by the inferior constrictors of the pharynx, acting upon the sides of the thyroid cartilage. 



The epiglottis, the superior vocal chords, and the ventricles, are by no means indis- 

 pensable to the production of vocal sounds. In the formation of higli notes, the epiglottis 

 is somewhat depressed, and the superior chords are brought nearer together ; but this 

 only affects the character of the resonant cavity above the glottis. In low notes . the 

 superior chords are separated. It was before the use of the laryngoscope in the study of 

 vocal phenomena that the epiglottis and the ventricles were thought to be so important 

 in phonation. Undoubtedly the epiglottis has something to do with the character of the 

 voice ; but its function in this regard is not absolutely necessary, or even very important, 

 as has been clearly shown in experiments of excising the part in living animals. 



The most important modifications of the laryngeal sounds are produced by the reso- 

 nance of air in the pharynx, mouth, and nasal fo^sse. This resonance is indispensable to 

 the production of the natural human voice. Under ordinary conditions, in the production 

 of low notes the velum palati is fixed by the action of its muscular fibres, so that there is 

 a reverberation of the bucco-pharyngeal and naso-pharyngeal cavities; that is, the velum is 

 in such a position that neither the opening into the nose nor into the mouth is closed, and 

 all of the cavities resound. As the notes are raised, the isthmus contracts, the part imme- 

 diately above the glottis is also constricted, the resonant cavity of the pharynx and mouth 

 is reduced in size, until finally, in the highest notes of the chest-register, the communica- 

 tion between the pharynx and the nasal fossae is closed, and the sound is reenforced 

 entirely by the pharynx and mouth. At the same time the tongue, a very important 

 organ to singers, particularly in the production of high notes, is drawn back into the 

 mouth. The point being curved downward, its base projects upward posteriorly and 

 assists in diminishing the capacity of the cavity. In the changes which the pharynx thus 

 undergoes in the production of different notes, the uvula acts with the velum and assists 

 in the closure of the different openings. In singing up the scale, this is the mechanism, 

 as far as the chest-notes extend. When, however, we pass into what is known as the 

 head-voice, the velum palati is drawn forward instead of backward, and the resonance 

 takes place chiefly in the naso-pharyngeal cavity. 



Mechanism of the different Vocal Registers. There has been a great deal of discus- 

 sion, even among those who have studied the voice with the laryngoscope, with regard 

 to the exact mechanism of the different vocal registers. It is now pretty well settled 

 how the ordinary notes of what is known as the chest-register are produced ; but, with 

 regard to the falsetto, the difficulties in the way of direct observation are so great, that 

 the question of its mechanism cannot be said to be definitively established. 



The following are the vocal registers now recognized by most physiologists : 



1. The chest-register, most powerful in male voices and in contraltos, and, indeed, 

 almost characteristic of the male. 



2. The falsetto register, which is the most natural voice of the soprano ; though this 

 voice is capable of chest-notes, not so full, however, as in the contralto or in the male. 

 In the female this is known as the middle register. 



3. The head-register, produced by a peculiar action of the glottis and the resonant 

 cavities above the larynx. This is cultivated particularly in tenors and in the female. 



Aside from the three registers, which belong to every voice, a practised ear can find 

 no difficulty in distinguishing the different voices in nearly any part of the scale, both in 

 the male and the female, by the following peculiarities : In the bass, the low notes are 

 full, natural, and powerful, and the higher notes nearly always seem more or less artifi- 

 cial. In singing, the passage from the natural to the artificial notes in the scale is gen- 

 erally more or less apparent. In the tenor the full, natural notes are higher in the scale, 



