The great physiologist, Johannes Müller, fastened a larynx, which he
had cut out with the whole trachea belonging to it, to a board, and,
stretching the vocal chords by a weight that could be increased or
diminished at pleasure, caused vibrations in it by blowing through
the trachea with a pair of bellows, or through a tube with his own
breath. In this way he succeeded in producing almost all the tones
of the human voice, and even some which are beyond the compass of
this organ.
He distinguished two different kinds of tones, to which he gave
the names of the chest register and the falsetto register. The
chest tones were produced when the vocal ligaments, slackly
stretched, were made to vibrate easily in their whole breadth;
the falsetto tones came merely through the vibration of the fine
inner edges of the vocal chords when they were more tightly
stretched. At a moderate stretching of the vocal chords, it
depended upon the manner of blowing whether a sound corresponding
to the chest voice or to the falsetto were produced, or whether
it were higher or lower for several tones, often for a whole
octave. A series of tones of more than two octaves could thus be
produced in the same larynx, with, however, gaps and places at
which the vocal chords, instead of being stretched gradually,
have to be _stretched at once very strongly, in order that the
succeeding higher half tone may be reached_. Such a place Müller
indicates from c² to c♯², or d² to d♯², with the remark that it
differs in different larynxes, being in some higher and in some
lower. But in order to render practicable the proper stretching
of the exsected larynx, muscles and membranes have to be cut,
which sufficiently proves that the functions of the organ of
singing in the living must be differently carried on.
_Dr. Merkel_, in Leipzig, has continued these experiments, and
by means of a peculiar contrivance has succeeded in producing
all the tones in the exsected larynx, without mutilating it.
But these investigations, interesting as they are, throw no
certain light upon the formation of sound by the vocal organ
in the living.
The celebrated singing master, _Manuel Garcia_, now living in
London, was the first to adopt the right mode of scientific
inquiry in this department, with favorable results. He undertook
to apply the laryngoscope (previously invented by the Englishman,
_Liston_) to the larynx in the act of singing. The interesting
results of these observations were published by him in the
Philosophical Mag. and Journal of Science, vol. x. p. 218. While
men of science immediately repeated Garcia's experiments and
applied them with the greatest advantage to pathological purposes,
they were received with distrust, scarcely noticed, and in many
instances entirely rejected, by teachers of vocal music. The few
who attempted to follow the path thus opened soon gave it up,
because they lacked either patience or the anatomical knowledge
necessary to such investigations.
The laryngoscope is well known among medical men. It is a small
plane mirror of glass or metal, having a long handle. Before it
is introduced into the throat, it is first warmed, to prevent
its becoming dimmed. The reflecting surface of this instrument
is directed downwards and forwards, so that it receives the
reflection caught from a concave mirror, and presents to the
eye of the observer a picture of the illuminated larynx. In
using it upon oneself, there is need of a second mirror, which
must be so held that the image may be seen in the laryngoscope.
The use of the laryngoscope requires in the observer a certain
adroitness and long-continued practice--almost more in the
observer than in the subject of observation. In self-observation
one must first learn to overcome the irritation always caused
at the first by the contact of the mirror with the back of the
throat. Once accustomed to the contact, one soon succeeds in
obtaining a sight of the larynx, sufficient for the most part
for pathological purposes. But it requires long practice before
one can control those organs, usually not immediately submissive
to the will, and raise the epiglottis, so as to be able to see
into the whole larynx. But this is absolutely indispensable, in
the observation of the formation of sound, to the attainment of
any substantial results. Garcia says himself that _one-third
of the glottis_ was always _hidden_ from him by the epiglottis,
and to this circumstance is the unsatisfactory character of his
observations to be ascribed. But even when, after long practice,
one is able at last to bring the whole glottis into view, this
is not by any means enough. Not until observation has been so
long continued that all the movements of the vocal organ are
normal, notwithstanding the unnatural drawing back of the
epiglottis, and not until the process that goes on is found
again and again to be always the same, can it be recognized
as fact.
As Garcia is the most eminent of singing masters now living,
and as he has sought, solely in the interest of vocal music,
to ascertain the mechanism by which sound is formed, and as
his observations have been confirmed by men of science, I
give them here in his own words.
In order that what follows may be better understood by those
unacquainted with anatomy, a brief anatomical description of
the vocal organ will be found in an Appendix to the present
work.