568 
MR. BISHOP ON THE PHYSIOLOGY 
Muller also states that the arches of the palate may be touched by the finger without 
altering the pitch, which could not be the case on the hypothesis of Bennati. It is 
to be remarked that neither Muller nor Bennati mentions the opening of the crico- 
thyroid chink on sounding the first note in the falsetto register; neither do they men- 
tion the simultaneous falling of the larynx, and they deny the existence of a third 
register. According to the hypotheses of Lehfeldt and Muller, any increased in- 
tensity of vocal sound ought to raise the pitch of the voice ; but if this were the case, 
the performance of prolonged vocal sounds on the same note, but of variable inten- 
sity, would be rendered impossible without a simultaneous adjustment between the 
tension of the vocal ligaments and the current of air; whereas, by examining the 
state of the crico-thyroid chink during the utterance of such sounds, it is found that 
no such adjustment takes place. The exquisite quality of the sounds of the larynx, 
when modified by the oral and nasal cavities, renders the human voice far superior 
to any artificial musical instrument ; since its tones glide through all the en-harmonic 
intervals between successive notes, an effect which no such instrument can perfectly 
imitate. Dodart estimates the number of tones, which can be produced by the voice 
and appreciated by the ear in the compass of an octave, at three hundred: a striking 
proof of the complete control exercised by the laryngeal nerves over the vocal ap- 
paratus. 
The action of the vocal organs in producing speech is a distinct branch of the phy- 
siology of voice which the author does not intend now to investigate. It is well 
known that the vowel sounds have been imitated by Kratzenstein, De Kempelen 
and Willis by means of mechanism, and that the principles on which they depend have 
been successfully analysed by the latter: but this is a subject which would require a 
very lengthened examination to render it the justice which its importance demands*. 
Having now completed the investigation of the physiological character of the 
human organs of voice, and having for the sake of simplicity considered them in 
three distinct lights ; namely, as membranous ligaments obeying the laws of musical 
strings, as a reeded instrument, and as a membranous pipe with a column of air 
vibrating within it, the results of the various experiments which have been noticed 
would certainly seem to warrant the conclusion that each of these views is cor- 
rect ; for it cannot be denied that these experiments clearly show the vocal apparatus 
to be influenced by the air expelled from the chest in precisely the same way as if it 
were a stretched cord, a reed, or a vibrating tube. Why then should, we hesitate to 
adopt the obvious conclusion that the vocal organs do in fact combine the properties 
of these various instruments, and are themselves the perfect types of which these in- 
struments are only imperfect imitations? The error of those who have preceded the 
author in this inquiry seems to consist in viewing the organs of voice, not as a coin- 
* The Abbe Mical, Faber and Mr. Wheatstone have succeeded in producing articulate language by means 
of artificial mechanism ; the Abbe, having so far completed the apparatus as to be capable of performing almost 
any sentence, appears to have destroyed his machinery owing to pecuniary disappointment. 
