The larynx is a sound-giving organ belonging to that class of
wind instruments called reed instruments, although it differs in
various respects from all artificial arrangements of the kind.
The sound or tone-generating apparatus of the larynx consists of
tense, elastic _membranes_, the so-called _chordæ vocales_, which
are enclosed in a sounding case composed of movable cartilaginous
plates, and may be stretched by a certain apparatus of muscles in
very different and exactly measurable degrees. They are made to
vibrate audibly by a current of air impelled with various degrees
of force and at will by the lungs in expiration through the
narrow chink (glottis) formed by the fine edges of the chords.
Thus the lungs correspond to the bellows of the organ; the
trachea, at the top of which the vocal instrument is placed,
answers to the conduit (_Windrohr_), and the cavity of the throat
in front of the instrument with its two avenues, the mouth and
the nostrils, to the resonance pipe (_Ansatzrohr_).