This instrument
is a small, round mirror which is introduced into the throat at such an
angle, that if horizontal rays of light are thrown upon it, the larynx,
which lies directly beneath, is illuminated and reflected in the mirror
at the back of the mouth-- the laryngoscope. Very many singers and
teachers, of whom Manuel Garcia was the first, have made use of this
instrument to observe the action of their vocal bands in the act of
singing, and the results of these observations are of the greatest
value. Still, as before said, the laryngoscope does not reveal all the
secrets of voice-production. While it tells unerringly of any departure
from the normal, or of pathological change in the larynx, it does not
tell whether the larynx belongs to the greatest living singer or to one
absolutely unendowed with the power of song. Also, the subject of vocal
registers is as vexing to-day as ever.

While, then, we may confidently expect further and more complete
elucidation of the physiology of the voice, there is yet sufficient data
to guide us safely in vocal training, if we neglect not the empirical
rules which the accumulated experience of the past has established.

The organ by which the singing-voice is produced is the larynx. It forms
the upper extremity of the windpipe, which again is the upper portion
and beginning of the bronchial tubes, which, extending downward, branch
off from its lower part to either side of the chest and continually
subdivide until they become like little twigs, around which cluster the
constituent parts of the lungs, which form the bellows for the supply of
air necessary to the performance of vocal functions. Above, the larynx
opens into the throat and the cavities of the pharynx, mouth, nose, and
its accessory cavities, which constitute the resonator for vocal
vibrations set up within the larynx.

The larynx itself consists of a framework of cartilages joined by
elastic membranes or ligaments, and joints. These cartilages move freely
toward and upon each other by means of attached muscles. Also the larynx
as a whole can be moved in various directions by means of extrinsic
muscles joined to points above and below.

The vocal bands are two ligaments or folds of mucous membrane attached
in front to the largest cartilage of the larynx, called the thyroid, and
which forms in man the protuberance commonly called Adam's apple; and,
extending horizontally backward, are inserted posteriorly into the
ary