actions. Try to ascend a single flight of stairs, performing
each elementary movement by a distinct volitional impulse. Pause on the
first step to secure perfect balance on one foot; raise the other foot,
bending the leg at the knee, then place this foot carefully on the next
higher step. Now gradually shift the weight of the body from the lower
to the higher foot; as the body inclines forward, exert the muscles of
the back and sides to preserve your balance; then contract the leg
muscles so as to raise the body to the higher step, with the weight
supported on that foot. Repeat this operation for each step. To mount
one flight of stairs in this way will tire you more than ascending a
half dozen flights in the ordinary automatic way.

All four of the types of involuntary muscular contraction just described
may be combined in a single instance. An inexperienced violin soloist,
such as a student playing at a conservatory recital, often exemplifies
this. Nervousness and awkwardness cause him to tremble; the scratchy
sound of his tones makes him twitch and start; meanwhile, the close
attention paid to his fingering and bowing stiffens his arms and
completes his difficulty.

The vocal organs are peculiarly subject to the forms of involuntary
muscular contraction under consideration. Each of the causes of muscular
tension may exert its special influence on the voice. Let us go over the
ground once more, this time with special reference to the actions of the
throat muscles.

_(a) Reflex Actions of the Muscles of the Vocal Organs, Independent of
Direct Sensory Excitation_

Involuntary actions of the vocal organs normally occur in response to
stimuli furnished by the emotions and feelings. Every one is familiar
with the shout of triumph, the sigh of relief, and the ejaculation of
surprise. Some emotions cause a convulsive stiffening of the muscles of
the vocal organs so complete as to render tone-production for a time
absolutely impossible. "Speechless with terror," "breathless with
apprehension," are expressions which accurately describe psychological
processes. A crowd of people watching a difficult rescue of a drowning
man is silent so long as the uncertainty lasts. A shout instantly goes
up when the rescue is seen to be safely effected. Both the silence of
the nervous strain and the shout of relief are normal involuntary
responses to the emotional states.

_(b) The Influence of Nervousness on the Vocal Action_

Nervou