the _glide_ of the glottis. This is often a matter of great
difficulty, requiring much patience and perseverance on the part of the
teacher as well as on that of the student. The _glide_ of the glottis is
particularly hard to eradicate, and in many instances the case seems to
be hopeless. Do not, however, despair, but try this: Pronounce
vigorously the word "Up." Then _whisper_, but still very vigorously and
distinctly, three times the vowel _u_, as you just had it in the word
"up." Immediately afterwards _sing_ "Ah." Thus--

UP! _u_, _u_, _u_, Ah.
(_spoken_) (_whispered_) (_sung_)

I recommend this device from extended personal experience, and hope my
fellow-teachers may find it as useful as I have found it myself. Another
point of importance in practising the exercise for strengthening the
opening and the closing muscles is the breathing after every tone; and
this must be done gently and without effort, the only perception which
the singer should have of it being a slight movement of the midriff.
When you can sing the exercise in this manner on _F_, your supposed
speaking tone, then go up the scale, semitone by semitone, to _B_ or _C_
above, and down again, semitone by semitone, to _B_ or _C_ below. Of the
quality of tone I will say nothing here, because that part of the
subject will be discussed later on in connection with the tongue and the
soft palate.

The next thing in connection with the physiology of the vocal organ from
which we can deduct a practical lesson is the action of the muscles
governing the pitch of the voice. This process is a very complex one,
and can be made clear only by _viva voce_ explanations, with the help of
good models and moving diagrams, by demonstrations with the
laryngoscope, and by carefully watching external signs. There is no
doubt, however, that a set of muscles, described as the "Stretching and
Slackening Muscles," play the most important part in this matter, and I
advise the reader to study carefully the chapter on "The Movements of
the Voicebox," and try the experiments mentioned in it. It will thus be
seen that the flexibility of the voice depends in a great measure upon
the control we have over the muscles governing the pitch; that is to
say, upon the readiness and exactness with which we are able to allow
them to contract or to relax.

Performers upon various instruments, as for instance the piano and the
violin, know that certain exercises are indispen