of which they are
the most easily observed examples. As a result of this squeezing there
is in some cases that reddening of the face and that tightness which
is often felt uncomfortably, and which is _straining_, because when
present in more than a very slight degree it is injurious, owing to
congestion or accumulation of blood in the blood-vessels, with all the
bad consequences of such a state of things. When the tightening does
not go beyond a certain point it is normal--indeed, such sphincter
action is inevitable; but it is the excess which is so common in
tenors and others who strain for undue power, and to produce tones too
high in pitch for their development or their method, which is so
disastrous to the throat and to the best art also.

[Illustration: FIG. 33 (Spalteholz). Shows various structures, and
especially well the false and the true vocal bands, with the space
between them (ventricle of Morgagni), but which has no special
function in phonation, unless it acts as a small resonance-chamber,
which is possible. This space is a natural result of the existence of
two pairs of vocal bands in such close proximity.]

[Illustration: FIG. 34 (Spalteholz). Parts have been cut away to
expose to view the whole of the inner surface of the larynx (lined
with mucous membrane). An excellent view of the vocal bands and of the
"ventricle" of the larynx, between them, is afforded.]

When the vocal bands are in action their vibrations are accompanied by
corresponding vibrations of the cartilages of the larynx--a fact of
which any one may convince himself by laying his fingers on the upper
part of the thyroid, especially when a low and powerful tone is
produced. This vibration is not confined to the larynx, but extends to
other parts--_e.g._, the chest itself, for when one speaks or sings a
distinct vibration of the chest walls can be felt, though the extent
to which this is present is very variable in different persons. As an
ascending scale is sung the larynx can be felt (by the fingers) to
rise, and the reverse as the pitch is lowered. This is due partly to
the action of those muscles attached to the larynx which are not
connected with the movements of the vocal bands, and partly to the
influence of the expiratory air-blast. The glottis, partially closed
as it must be in phonation, presents considerable resistance to the
outgoing stream of air, hence the upward movement of the larynx when
it is left free, and not held do