[Description: Fig. 11.--Drawings after Dr. French's photographs in Sir
Felix Semon's lecture on the Voice, (1) Appearance of vocal cords of
contralto singer when singing F# to D; it will be observed that the cords
increase in length with the rise of the pitch, presumably the whole cord is
vibrating, including the inner strand of the vocal muscle. At the break
from D to E (3 and 4) the cords suddenly become shorter and thicker;
presumably the inner portion of the vocal muscle (thyro-arytenoid) is
contracting strongly, permitting only the edge of the cord to vibrate. For
the next octave the cords are stretched longer and longer; this may be
explained by the increasing force of contraction of the tensor muscle
stretching the cords and the contained muscle, which is also contracted.]

When we desire to produce a particular vocal sound, a mental perception of
the sound, which is almost instinctive in a person with a musical ear,
awakens 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 kinæsthetic (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