306 OF THE VOICE AND SPEECH. 



may be added, that the partial closing of the epiglottis seems to assist in the 

 production of deep notes, just as the partial covering of the top of a short pipe 

 fixed to a reed will lower its tone ; and that something of this kind takes 

 place during natural vocalization, would appear, from the retraction and 

 depression of the tongue which accompany the lowering of the front of the 

 head, when the very lowest notes are being sounded. The arches of the 

 palate and uvula become contracted during the formation of the higher tones; 

 but no difference can be perceived in their state, whether these tones be falsetto 

 or not ; hence it would appear, that they have no concern in this peculiarity ; 

 and the purpose of their increased tension is probably to maintain their power 

 of resonance. The experiments of Savart have shown that a cavity which 

 only responds to a shrill note when its walls are firm and dry, may be made 

 to afford a great variety of lower tones, when its walls are moistened and 

 relaxed in various degrees. This observation may probably be applied also 

 to the trachea. 



412. These and numerous other muscular actions which are employed in 

 the production and regulation of the voice, are effected by an impulse which 

 can scarcely be termed Voluntary, and the nature of which is a curious sub- 

 ject for inquiry. It may be safely affirmed that the production of sounds is in 

 itself an Instinctive action ; although the combination of these, whether into 

 music or articulate language, is a matter of acquirement. Now it might be 

 supposed that the Will has sufficient power over the vocal muscles, to put 

 them into any state requisite for its purposes, without any further condition ; 

 but a little self-experiment will prove that this is not the case. No definite 

 tone can be produced by a Voluntary effort, unless that tone be present to the 

 mind, during however momentary an interval, either as immediately conveyed 

 to it by an act of Sensation, recalled by an act of Conception, or anticipated by 

 an effort of the Imagination. When thus present, the Will can enable the 

 muscles to assume the condition requisite to produce it ; but under no other 

 circumstances does this happen, except by a particular mode of discipline 

 presently to be adverted to. The action itself, therefore, must be reduced to 

 the class of consensual movements ; and we must suppose that the Will is 

 exercised in preparing the conditions requisite for it, rather than in directly 

 exciting it. That those who are unfortunately labouring under congenital 

 deafness, are thence debarred from learning the use of Voice in the ordinary 

 manner, is well known ; the consensual action cannot be excited, either through 

 sensations of the present, or conceptions of the past ; and the imagination is 

 entirely destitute of power to suggest that which has been in no shape expe- 

 rienced. But such persons may be taught to speak in an imperfect manner, 

 by causing them to imitate particular muscular movements, which they may 

 be made to see ; and it is evident, that they must be guided in the imitation 

 and ordinary performance of those movements, by the common muscular sen- 

 sations which accompany them, and not by the sensations conveyed through 

 the Auditory nerve, which are ordinarily by far the most precise guides. 

 Many instances, indeed, are on record, in which persons entirely deaf were 

 enabled to carry on a conversation in the regular way ; judging of what was 

 said, by the movements of the lips and tongue, which they had learned to 

 connect with particular syllables ; and regulating their own voices in reply, 

 by their voluntary power, guided by muscular sensation.* 



[In the foregoing account of the Physiology of Voice, the Author has been chiefly 

 guided by the excellent paper by Mr. Willis in "the transactions of the Cambridge Philo- 

 sophical Society, vol. iv., and by the elaborate investigations of Mailer and his coadju- 

 tors, as detailed in the Fourth Book of his Physiology.] 



* See Johnstone on Sensation, p. 128. 



