Evening star., 1935-04-13
STARS, MEN AND ATOMS
Notebook of Science Progress in Field,
Laboratory and Study.
BY THOMAS r. HENRY.

gans only on account OF series OF
accidents.
Nature never intended him to have
them, according to report of V. E.
Negus. noted British anthropologist,
to the International Congress of An
thropology and Ethnology.
His ancestors were given vocal cords
for fixstion of the chest while the
forearms were used in climbing.
He is able to alter the rate Of vi
bration of these cords-and hence
produce tones-by the contraction of
certain muscles, the sphincteric
group, while air is being expelled
from the lungs. This muscle group
was given man for protection Of the
air tract leading to the lungs from
the entrance of food or water.
So man Is able to talk, DR.. Negus
points out, through the retrogres-
sion of various parts of his anatomy,
evolved for specialized purposes,
which have ceased to have their origi-
nal Importance and have undergone
changes that are of benefit as regards
speech"
Take, for example, the larynx. In
both man and the apes this organ
possesses "long membranouS folds, the
vocal cords, capable of vibrating and
thus interrupting the exploratory cur
rent of air in rythmical manner. But
in the apes, and particularly in glib
bons and chimpanzees, the valvular
nature of these folds is more marked
than in man. In the latter. diminished
use of the arms for climbing has
resulted in a degenration of the folds
as fixation valves, but with gain as
regards phonation.
THE production Of tones and the
means of alteration Of the rate of
vibration of the foldS-with conse-
quent rise in pitch of the sound pro-
duced-appears to be due to the con-
traction of the sphincteric group Of
muscles which surround the glottis,
while air is expelled from the lungs.
The sound produced at the larynx does
not represent the voice. The latter
depends on amplification and modi-
fication of the laryngeal tones by
various resonators. Certain overtones
are accentuated while others are sup
pressed, with resulting variations in
Lne qualify OF tilc VOiCc.
MAN is in a peculiarly favorable
position as regards these resonators.
Assumption Of the erect posture, as
sociated with alterations in the size
and position Of the mouth and tongue,
has changed the position Of the
larynx. 1t is placed at low level in
the neck, with a wide gap between
the epiglottis and the soft palate.
Degeneration of the sense of smell
has allowed this separation to occur
without loss of efficiency.
"The descent Of the larynx has
brought into existence q large
pharyngeal resonator capable Of
alteration In shape and size. At the
same time the sound can be allowed
to escape at will through the nose
or mouth or both. while the mobile
cheeks, lips and tongue can be used
for articulation. In lemurs and
monkeys the epiglottis Is normally in
contact with the soft palate and no
pharynx is available for vocal proc
esses. In the higher apes the larynx
lies at q somewhat lower level and
the epiglottis Just reaches the palate.
In these again there Is no pharyngeal
resonator comparable to that Of man.
$50 notifications for various rea-
sons have provided man with EN-
cient organs capable Of use for vocal
purposes. His superior intelligence
has enabled him to take advantage
oS hiS opportunities"