VOICE. 





the base of the cranium. By placing the 

 finder on the pomum Adaini this motion can 



irresistibly to the conclusion, that there exists 

 a constant adaptation between the tension 



he easily felt, and at the same time the thyroid and the vibrating length of the thyro-an tenou 



cartilage is drawn up within the os-hyoides, ligaments and the walls of the vocal tube, i,i 



and presses on the epiglottis; the small space the production of tones of the ordinary re- 



A l -i J __ J "'ii ,i - /' i 



between the thyroid and cricoid closes, the 

 pharynx is contracted, the velum palati is de 



gister; for we have seen that the variations 

 of the vocal cords, at least as far as relates 



pressed and curved forward, and the tonsils to the modulation of sound, are perfectly in- 



approach each other : the reverse of these dependent of the length of the "vocal tube, 

 phenomena takes place during the descent of and consequently the changes in its length 



which we have just described are riot at all 

 necessary for that purpose. Again, the vocal 

 tube is so short, that, as has been ascertained 

 other changes being, on account of their situ- by Weber and others, it could not, were it 



the voice. These are the principal pheno- 

 mena common to most mammalia which can 

 be recognised by external observation; the 



Btion, invisible. 



The effects of these variations on the tone 

 of the voice have been hitherto little under- 

 stood. It has always appeared incomprehen- 

 sible why the vocal tube should apparently 



rigid, affect the pitch of the note produced by 

 the glottis. As however this tube is com- 

 posed of flexible materials, its effects are 

 similar to those observed in M. Savart's ex- 

 periments ; that is, the relaxed state of the 



in length in the production of the parietes compensates for its want of length, 



acute tones, and shorten in the grave ; a cir- and enables it to vibrate synchronously, and 



cumstance which theoretically presents an therefore to give forth sounds equally grave 



acoustic paradox. Dodart and many others with those of the glottis, thereby reinforcing 



have conceived the elevation of the larynx to the tone which would indeed be produced, 



be merely for the purpose of shortening the though with much less intensity, without this 



vocal tube in the supra-laryngeal cavity, and aid, 



have considered the trachea as producing no The Falsetto, or voccdi testa, has always been 

 effect on the pitch of the tone. Majtndie considered a most embarrassing subject of re- 

 has also pointed out the shortening of this search, and its peculiar quality has excited the 

 part of the tube. In order to ascertain the attention both of the physiologist and of the 

 effect of these changes, the following expeii- musician. Its most remarkable characteristic 

 ments were made on the dead body. Having consists in its being less reedy in tone and 



I - "It-- -._*!__ 1 f* II. _,. 1 " 1 / . 1 1 rt 



laid bare the vocal organs of an adult male, 

 1 raised the larynx to the position it would 

 occupy by the elevation of the voice to an 

 octave, being about half an inch, and at the 



partaking nearly of the quality of the har- 

 monic sounds of stringed and wind instru- 

 ments. The change produced in the voice 

 when passing from the falsetto into the corn- 



time minutely observed the position of nion tone, or the reverse, is in some persons 

 the lowest ring of the trachea with reference very sensible to the ear, whilst in others it is 

 to the sternum. By this operation 1 found the almost imperceptible. Some individuals, more- 

 over, have the faculty of producing in the same 

 pitch as many as eight or ten tones, possessing 

 either the falsetto or the common character. 



trachea was raised out of the chest, nearly 

 to the same extent as the larynx had been 

 elevated towards the base of the skull. The 



next step was to examine whether any change The falsetto has been general!}' ascribed to 



I 1 .*. . . 1 _ 1 A 1 i f+ . i .1 * 1 1 . . " / . i 



had taken place in the diameter of the tube. 

 For this purpose, having measured the diame- 

 ter of the trachea in its natural position, the 

 larynx was again elevated to the same extent 

 as before, when the diameter was found 

 diminished one-third. These experiments 



some particular adaptation of the upper liga- 

 ments of the larynx. Dodart * has attempted 

 to prove that it is a supra-laryngeal function, 

 and that the nose becomes the principal tube 

 of sound instead of the cavity of the mouth. 

 Bennati f also considered these tones as being 



prove that, contrary to the general precon- modulated by the supra-laryngeal cavity alone, 

 ception, the elevation of the larynx shortens 

 the tube independently of the contraction 

 between the thyroid cartilage and os-hyoides, 

 and at the same time lessens its diameter. 



This hypothesis, however, is untenable, since 

 it supposes the column of air not to be in- 

 fluenced by the trachea, which is contrary to 

 experience. In order to detect some of the 



The same effects may easily be detected dur- movements of the larynx while the voice is 

 ing life by placing the finger on the trachea passing from the first to the second, or falsetto 

 immediately above the sternum during the register, it is only necessary to place the point 

 elevation of the larynx, when the trachea is of the finger in the crico-thyroid chink, when 



it is found that at the moment the transition 

 from the primary to the secondary register 

 takes place, this chink, which was closed dur- 

 ing the production of the highest note of the 



diameter may also be perceived by grasping ordinary register, suddenly opens on the pro- 

 the trachea with the finger and thumb during duction of the first note of the falsetto register, 



found to ascend out of the chest, and alter" 

 wards to return to its former position ; a 

 movement in which the lungs and bronchi 

 participate. The alteration of the tube in 



the elevation and depression of the larynx.* 

 These movements are so striking as to lead 



* Essays by the author, in the London and Edin- 

 burgh Philosophical Magazine, for September, Oc- 

 tober, and November, 1836. 



and consequently the thyro-arytenoid liga- 

 ments are relaxed at the same moment the 



, * Mem. de 1'Acad. 1707. 



f Ptecherches sur le Mechanisme de la Voix 

 humaiue. 



