adjustment of the vocal cords" (Mackenzie).

From a consideration of the above proposed definitions it will be seen
that for the successful or, at all events, complete or ideal
investigation of a subject so many-sided and difficult, many
qualifications are desirable, if not absolutely essential. It is not
too much to say that the ideal investigator of the registers should
have a practical knowledge of general anatomy and physiology, together
with a detailed and exact knowledge of the vocal organs; be versed in
the laws of sound; have an adequate knowledge of music; be capable of
examining himself with the laryngoscope (auto-laryngoscopy) as well as
others (laryngoscopy); possess an acute ear for the pitch and quality
of tones; be himself able to use his voice at least fairly well in
singing and speaking; be provided with the all-important ballast of
common sense, and an impartial mind longing above all things to learn
the truth.

As few can hope to unite all these qualities in themselves in even a
moderate degree, openness of mind, temperance in the expression of
opinion, and common sense with experience, must be largely relied on
to furnish working conclusions.

A discussion of a subject so difficult and complicated is not easy to
follow. It is but just to other investigators, and fair to the reader,
to present the views of those who have possessed special
qualifications for dealing with the questions involved. The author
will endeavor to present the grounds on which others have taken their
stand, in a few words and clearly, if the reader will patiently
follow. There will at first seem, possibly, to be little agreement,
but it will be shown that on some of the most essential points there
is substantial unity of opinion; and the subject is of such vital
moment, as the author will endeavor to make clear, that it is hoped
that the most patient examination will be given to the questions that
arise, from the beginning to the end of the discussion. For the author
to express a dogmatic opinion, and simply state his disagreement or
agreement with others, would be contrary to the whole spirit of this
work, and leave the subject where it once was--in the realm of
hopeless disagreement and controversy. If the problem of the registers
is to be solved to the satisfaction of the rational thinker, it must
be by evidence, and not the mere opinions of any teacher or writer,
however eminent. To lay this evidence before the reader is