

ACTION OF ACCESSOEY VOCAL ORGANS. 495 



The fact that some singers can make the voice heard above the combined 

 sounds from a large chorus and orchestra is not due entirely to the intensity 

 of the sound, but in a great measure to the mathematical equality of the 

 sonorous vibrations and the comparative absence of discordant waves. 



Action of Accessory Vocal Organs. A correct use of the accessory organs 

 of the voice is of great importance in singing ; but the action of these parts 

 is simple and does not require a very extended description. The human 

 vocal organs, indeed, consist of a vibrating instrument, the larynx, and of 

 certain tubes and cavities by which the sound is re-enforced and modified. 



The trachea serves, not only to conduct air to the larynx, but to re-enforce 

 the sound to a certain extent by the vibrations of the column of air in its 

 interior. When a powerful vocal effort is made, it is easy to feel, with the 

 finger upon the trachea, that the contained air is thrown into vibration. 



The capacity of the cavity of the larynx 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 di- 

 ameter may be reduced by the action of the inferior constrictors of the 

 pharynx upon the sides of the thyroid cartilage. 



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

 means indispensable to the production of vocal sounds. In the emission of 

 high notes the epiglottis is somewhat depressed, and the superior chords are 

 brought nearer together ; but this affects the form of the resonant cavity only 

 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 action is not absolutely necessary or even very important, as 

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



The most important modifications of the laryngeal sounds are produced 

 by the resonance of air in the pharynx, mouth and nasal fossae. This reso- 

 nance 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 the opening into the 

 mouth is closed, and all of the cavities resound. As the notes are raised in 

 pitch, the isthmus contracts, the part immediately 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 

 re-enforced 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 backward. The point being curved downward, its 

 base projects upward posteriorly and assists in diminishing the capacity of 

 the bucco-pharyngeal cavity. In the changes which the pharynx thus under- 



