hydraulic press is presented by the chest cavity and the
larynx, considered as one apparatus. This fact is illustrated in the
following quotation: "If a bladder full of water be connected with a
narrow upright glass tube, heavy weights placed on the bladder will be
able to uphold only a very small quantity of liquid in the tube, this
arrangement being in fact a hydraulic press worked backwards. If the
tube be shortened down so as to form simply the neck of the bladder, the
total expulsive pressure exerted by the bladder upon the contents of the
neck may seem to be very small when compared with the total pressure
exerted over the walls of the bladder upon the whole contents." (_A Text
Book of the Principles of Physics_, Alfred Daniell, London, 1884.)

That the glottis-closing muscles are too weak to withstand a powerful
expiratory pressure is therefore an entirely erroneous statement. Owing
to the small area of the under surfaces of the vocal cords, the air
pressure against them is very small, in comparison with the total
pressure exerted on the contents of the thorax by the expiratory
contraction. The glottis-closing muscles are fully capable of
withstanding this comparatively slight pressure. The doctrine of
breath-control is therefore scientifically untenable. This doctrine has
no place in Vocal Science.

As the basic doctrine of breath-control is unsound, the singer does not
need any direct means for controlling the breath. The attempt to check
the flow of the breath in any mechanical way is entirely uncalled for.
This being the case, it is hardly to be expected that the systems
devised to meet this fancied need would stand the test of scientific
examination. Each of these systems of breath-control, opposed muscular
action and ventricular, is in fact found on analysis to embody a
misconception of scientific principles.

_Opposed-Action Breath-Control_

A curious misapprehension of mechanical processes is contained in the
doctrine of breath-control by opposed muscular action. This can best be
pointed out by a consideration of the forces brought to bear on a single
rib in the acts of inspiration and expiration. One set of muscles
contract to raise this rib in inspiration, an opposed set, by their
contraction, lower the rib for the act of expiration. In the
opposed-action system of breath-control, the action of the rib-raising
muscles is continued throughout the expiration, as a check upon the pull
in the opposite