is possible,
which shows the futility of the more or less violent effort involved in
pure diaphragmatic or abdominal breathing. Moreover, the hollow vein
(vena cava) which leads the blood back to the heart, passes through the
diaphragm, or, to be more exact, through its central tendon, and any
violent action of the diaphragm in taking in breath tends to stretch
this vein and, after a while, to create dizziness.

I should be sorry if what I have said regarding the diaphragm were to be
construed as belittling its importance as an aid to artistic breathing.
My comments are directed against the exaggerated importance attached to
it by advocates of wholly diaphragmatic or abdominal breathing, when it
is capable of physiological demonstration that violent effort will
accomplish no more with the diaphragm than that accommodating muscle
accomplishes of its own accord when the singer, in taking in breath,
correctly applies the principles of mixed costal and diaphragmatic
respiration. In women only one-fifth and in men only one-sixth of the
cavity needed for the inflation of the lungs can be made by sinking the
diaphragm, the remaining four-fifths and five-sixths being created by
the expansion of the ribs. Therefore, the diaphragm would be obliged to
move five or six times as far downward as the ribs move upward, in order
to make room for the same amount of air. In other words, the ribs need
only make about one-fifth or one-sixth as much effort as the diaphragm,
and effort--conscious, noticeable effort--is one of the first things to
be avoided in any art and especially in the art of singing. "If a full,
pan-costal inspiration be taken after a complete expiration," writes
Dr. Harry Campbell in his "Respiratory Exercises in the Treatment of
Disease," "no more air, or at all events only a small quantity, can be
inhaled by means of the diaphragm." This, however, should be construed
as meaning that, after the diaphragm has performed its correct function
in inspiration, any further violent effort on its part is practically
futile. For the term "full, pan-costal inspiration," substitute "mixed
costal and diaphragmatic," which will imply that the diaphragm has done
its duty by the singer--and it is that apparently effortless performance
of its duty that gives it its real importance. The diaphragm really is a
most courteous and accommodating muscle when its assistance is politely
invited, but most obstreperous when one tries to force it in