s one of the basic principles of Vocal Science. The most
influential published work in popularizing the doctrine of
breath-control was probably the book written jointly by Lennox Browne
and Emil Behnke, _Voice, Song, and Speech_, London, 1883.

This doctrine is of so much importance in Vocal Science and in modern
methods of instruction as to require a detailed explanation. The theory
of breath-control may be stated as follows:[3]

"In ordinary breathing the air is expelled from the lungs quietly, but
rapidly; at no point of the breathing apparatus does the expired breath
meet with resistance. In singing, on the contrary, the expiratory
pressure is much more powerful, yet the expiration must be much slower.
Furthermore, all the expired breath must be converted into tone, and the
singer must have perfect control over the strength and the speed of the
expiration. This requires that the air be held back at some point. The
action of holding back the breath must not be performed by the muscles
which close the glottis, for all the muscles of the larynx are very
small and weak in comparison with the powerful muscles of expiration.
The glottis-closing muscles are too weak to oppose their action to the
force of a powerful expiration. If the vocal cords are called upon to
withstand a strong breath pressure, they are seriously strained, and
their proper action is rendered impossible. In the same way, if the
throat be narrowed at any point above the larynx, so as to present a
passage small enough to hold back a powerful expiration, the entire
vocal mechanism is strained and forced out of its proper adjustment. The
singer must have perfect control of the breath, and at the same time
relieve the larynx and throat of all pressure and strain. To obtain this
control the singer must govern the expiration by means of the muscles of
inspiration. When the lungs are filled the inspiratory muscles are not
to be relaxed as in ordinary breathing, but are to be held on tension
throughout the action of expiration. Whatever pressure is exerted by the
expiratory muscles must be almost counterbalanced by the opposed action
of the muscles of inspiration. The more powerful the blast, the greater
must be the exertion by which it is controlled. In this way the singer
may have perfect control both of the speed and of the strength of the
expiration."

[Note 3: This statement of the doctrine of breath-control must not
be construed as an endorsement of the