wakens by association motor centres in the brain that preside over the
innervation currents necessary for the approximation and minute alterations
in the tensions of the vocal cords requisite for the production of a
particular note. We are not conscious of any kinaesthetic (sense of
movement) guiding sensations from the laryngeal muscles, but we are of the
muscles of the tongue, lips, and jaw in the production of articulate
sounds. It is remarkable that there are hardly any sensory nerve endings in
the vocal cords and muscles of the larynx, consequently it is not
surprising to find that the ear is the guiding sense for correct modulation
of the loudness and pitch of the speaking as well as the singing voice. In
reading music, visual symbols produced by one individual awakens in the
mind of another mental auditory perceptions of sound varying in pitch,
duration, and loudness. Complex neuro-muscular mechanisms preside over
these two functions of the vocal instrument. The instrument is under the
control of the will as regards the production of the notes in loudness and
duration, but not so as regards pitch; for without the untaught instinctive
sense of the mental perception of musical sounds correct intonation cannot
be obtained by any effort of the will. The untaught ability of correct
appreciation of variations in the pitch of notes and the memorising and
producing of the same vocally are termed a musical ear. A gift even to a
number of people of poor intelligence, it may or may not be associated with
the sense of rhythm, which, as we have seen, is dependent upon the mental
perception of successive movements associated with a sound. Both correct
modulation and rhythm are essential for melody. The sense of hearing is the
primary incitation to the voice. This accounts for the fact that children
who have learnt to speak, and suffer in early life with ear disease, lose
the use of their vocal instrument unless they are trained by lip language
and imitation to speak. The remarkable case of Helen Keller, who was born
blind and deaf, and yet learned by the tactile motor sensibility of the
fingers to feel the vibrations of the vocal organ and translate the
perceptions of these vibrations into movements of the lips and tongue
necessary for articulation, is one of the most remarkable facts in
physiological psychology. Her voice, however, was monotonous, and lacked
the modulation in pitch of a musical voice. Music meant little to her bu