28 TEE FUNCTIONS OF THE UVULA. 



uvula and a small part of the central portion of the velum to rest on the 

 base of the tongue (Fig. 6), for sounds that passed mostly through the nose 

 and a little through the mouth; or, (d) still lower, so that its whole free 

 border rested on the base of the tongue (Fig. 4), for the formation of sounds 

 that passed the nose alone. In a few instances, as have been mentioned, I 

 have seen the second and third positions combined, i. e., the uvula resting 

 on the base of the tongue, and the azygos prominence touching the poste- 

 rior wall of the pharynx at the same time (Figs. 6 and 3). 



From the effects of these positions of the velum on phonation, it would 

 appear that one of its functions is to act as a valve, by directing the voice 

 from the larynx into the mouth alone for the formation of one kind of 

 tone; into the nose alone for another; and to divide the sound so as to allow 

 it to escape from both of these openings, for still others. It is evident that 

 while the velum is resting wholly on the base of the tongue, or is pressed 

 against the posterior wall of the pharynx, the liability for its free border 

 to vibrate by the force of the air is reduced to a minimum; but when this 

 valve is in either position that requires it to divide the sound between the 

 mouth and the nose, then, on account of its free edge being suspended and 

 placed immediately in the current of air from the larynx, the liability for 

 it to vibrate is increased to a maximum. 



A provision is necessary to prevent these vibrations. This provision, I 

 am led to believe from my observations, is found in the uvula and the azygos 

 prominence formed by the azygos uvulae muscles. It is located in the centre 

 of this very mobile palate or valve, and by its support in both of the posi- 

 tions that require suspension (Figs. 3 and 4), prevents it from being shaken 

 by the force of the current of air from the lungs. There can be no doubt, 

 that if there were no uvula and azygos prominence to prevent this thin 

 edge of suspended flesh from vibrating, it would be shaken to such a degree 

 as to impart a tremulousness to the tone of all sounds forcibly uttered that 

 pass through the mouth and nose at the same time. 



The following questions have been asked frequently: 



"1st; If the uvula is required to prevent the free border of the velum 

 from vibrating during phonation, will not its loss impair the voice?" 



"2d. How do you account tor the improvement of the voice in many 

 instances, after its removal?" 



The excision of the uvula can effect those sounds only which are formed 

 by its assistance, and not even then, if they are pronounced with the usual 

 strength of voice, because the contact of the central portion of the velum 

 on the base of the tongue will be support enough to prevent the velum from 

 being shaken; therefore, the difficulty in pronouncing, in high and loud 

 tones, those sounds that are required to pass mostly through the nose and 

 a little through the mouth, will be in proportion to the amount of loss of 

 support that the velum suffers; as usual excisions leave a stump of the 

 uvula and the central portion of the soft palate, these will prevent any vi- 

 brations during speech made with the usual force of the lungs. 



