ance chambers were thought to simply take up these
vibrations and determine nothing but the quality of tone.... It seems
probable that the vocal bands so beat the air within the resonance
chambers as to determine the rate of vibration of the air of these
cavities, and so the pitch of the tone produced." This at least shows
dissatisfaction with the old theory and attaches some share of their
due importance to the resonance cavities, but it still is far from
describing the correct phenomenon of voice-production.

Show a lateral section of a larynx to a trumpet or horn player and he
will at once recognize its similarity to the cupped mouthpiece and tube
of trumpet or horn, the cup in the larynx being formed by the ventricles
or pockets above the vocal cords. Extend the picture so that it includes
not only the larynx but the resonance cavities of the head as well, and
the cornet, trumpet or horn player will recognize the similarity to the
tube of his instrument as it turns upon itself. The manner in which the
lips shape themselves as the player blows into the instrument, the form
and size of the cup, the gyration and friction of the air within it and
within the bent portion of the tube, determine the pitch and the quality
of the tone that issues from the bell of the instrument.

The shape assumed by the lips, which are capable of many exquisite
variations in shape, conditions the form of the air-column as it enters
the cup of the trumpet or horn. This I believe to be one important
function performed for the larynx by the vocal cords, which Mackenzie,
with an aptness he could not have appreciated, called the lips of the
glottis. They are, in fact, the lips of the essential organ of voice,
the larynx. If they are looked at from below they will be seen to be
bevelled, and their resemblance to lips even more striking.

While, however, the importance of the vocal cords in tone-production
has been overestimated, I should be going to the opposite extreme if I
limited their importance to their function as the lips of the glottis.
Not only are they lips, but vibrating lips, their vibrations, however,
requiring enforcement through the sympathetic vibrations which they
generate within the cup of the larynx and in the cavities above. As
lips, the vocal cords shape the air-column as it enters the larynx, to
the required note; as vibrating lips--set into vibration by the very
air-column to which they have given shape--they start the vib