se breaks in both male and
female voices occur at certain pitches where the tone-producing
mechanism of the larynx changes action, and brings the vocal bands into
a new vibratory form. "A register consists of a series of tones produced
by the same mechanism."-- Emil Behnke in "Voice, Song, and Speech."
G. Edward Stubbs, in commenting upon the above definition, says:

"By mechanism is meant the action of the larynx which produces
_different sets of vibrations_, and by register is meant the range of
voice confined to a given set of vibrations. In passing the voice from
one register to another, the larynx changes its mechanism and calls into
play a different form of vibration."

The number of vocal registers, or vibratory forms, which the vocal bands
assume, is still a matter of dispute, and their nomenclature is equally
unsettled. The old Italian singing-masters gave names to parts of the
vocal compass corresponding to the real or imaginary bodily sensations
experienced in singing them; as chest-voice, throat-voice, head-voice.
Madame Seiler, in "The Voice in Singing," gives as the result of
original investigations with the laryngoscope five different actions of
the vocal bands which she classifies as "first and second series of the
chest-register," "first and second series of the falsetto register" and
"head-register." Browne and Behnke, in "Voice, Song, and Speech," divide
the male voice into three registers, and the female into five. They are
termed "lower thick," "upper thick," "lower thin," "upper thin" and
"small." Other writers speak of three registers, "chest," "medium" and
"head," and still others of two only, viz., the chest and the head.

Modern research has shown what was after all understood before, that, if
the vibratory form assumed by the vocal bands for the natural production
of a certain set of tones is pushed by muscular exertion above the point
where it should cease, inflammation and weakening of the vocal organs
will result, while voice-deterioration is sure to follow.
A physiological basis has reinforced the empirical deductions of the old
Italian school. In dealing with children's voices, it is necessary to
recognize only two registers, the thick, or chest-register, and the
thin, or head-register. Further subdivisions will only complicate the
subject without assisting in the practical management of their voices.
Tones sung in the thick or chest-register are produced by the full, free
vibration of