The fundamental conditions of singing demanded by Nature we find are as follows: 

  Natural or automatic adjustment of the organ of sound, and of all the
  parts.

  Approximation of the breath bands.

  Inflation of all the cavities.

  Non-interference above the organ of sound.

  Automatic breath-control.

  Freedom of form and action of all the parts above the larynx.

  High placing and low resonance.

  Automatic articulation.

  Mental and emotional vitality or energy.

  Free, flexible, vitalized bodily position and action.

It is not my intention here to enlarge upon these conditions to any extent.  I have already done so in my last book, “Position and Action in Singing.”  I know many writers on the voice, and many teachers, do not agree with me on this subject of conditions; but facts are stubborn things, and “A physical fact is as sacred as a moral principle.”  “The sources of all phenomena, the sources of all life, intelligence and love, are to be sought in the internal—­the spiritual realm; not in the external or material.”  “A man is considerably out of date who says he does not believe a thing, simply because he cannot do that thing or does not understand how the thing is done.  There are three classes of people—­the ‘wills,’ the ‘won’ts,’ and the ‘can’ts’:  the first accomplish everything, the second oppose everything, and the third fail in everything.”  These things [these conditions] can be understood and fully appreciated by investigation only.  There is no absolute definite knowledge in this world except that gained from experience.

The voice in correct use is always tuned like an instrument.  This must be in order to have resonance and freedom, and this is done only through natural or automatic adjustment of all the parts.  In singing there are always two forces in action, pressure and resistance, or motor power and control.  In order to have automatic adjustment these two forces must prevail.  When the organ of sound is automatically adjusted, the breath bands approximate:  This gives the true resisting or controlling force.  When the breath bands approximate we have inflation of the ventricles of the larynx, the most important of all the resonance cavities, for when this condition prevails we have freedom of tone, and the inflation of all other cavities.  And not only this; it also enables us to remove all restraint or interference from the parts above the larynx, and especially from the intrinsic and extrinsic muscles of the throat.  This automatic adjustment, approximation of the breath bands and inflation of the ventricles, gives us a yet more important condition, namely, automatic breath control; this is beyond question the most important of all problems solved for the singer through this system of flexible vitalized movements.