306 SIR CHARLES BELL ON THE ORGANS OF THE HUMAN VOICE. 
raging him, when no sound proceeded, by saying that I could understand him 
by the motion of his lips, I have seen that in the attempt at utterance, the 
glottis moved as well as the lips. Although these occasions be too painful to ad- 
mit of protracted experiment, I could not omit observing that there is a motion 
of the glottis in correspondence with the efforts of the other organs of voice. 
We have already understood the necessity of the tongue of the organ-pipe 
being adjusted in its length, both to the force of the wind from the bellows, 
and that it may vibrate in correspondence with the column of air in the tube. 
Granting that the analogy between this instrument and the organ of the voice 
is just, we must acknowledge the very superior means possessed by the living 
parts, of drawing out the margin of the glottis, to that by which the tongue of 
the organ-pipe is adjusted. 
If we should adopt the fancy to compare the membrane which is stretched 
over the ligament to a drum, then the arytenoid muscles would be the braces 
to tighten the membrane, and the ligaments would be as the snares on the 
reverse of the drum. But all such comparisons serve to show that, taking this 
portion only of the apparatus for the voice, it surpasses every instrument in 
the property of accommodation — of sounding in unison with the rest of the 
tube, and with the column of air. 
Of the Pharynx, and of the formation of articulate Sounds. 
We come now to a division of our subject, which, notwithstanding its higher 
interest, has been imperfectly treated by authors, and where the actions essen- 
tial to articulate language have been altogether omitted. 
Tracing the volume of simple sound in its ascent from the glottis, we see 
how well the epiglottis is calculated to direct it on the passages above*. Im- 
mediately over the epiglottis hangs the velum palati ; this curtain is formed 
by certain muscular fibres, which draw down the mucous membrane from the 
back part of the bony palate into a great fold ; whilst other muscles, their 
opponents, furl it up. This velum forms a partition which divides the mouth 
from the posterior cavity, arriere-bouche, or pharynx ; and the velum, uvula, 
and arches of the palate vary their condition during the production of simple 
sounds. 
* See Plate IX. 
