The Dawson news. (Dawson, Ga.) 1889-current, 1910-11-09
THE ENERGY OF OUR JAWS
AN INVESTIGATION IN FURTHER
ANCE OF SCIENTIFIC EATING.
1t Is Impossible to Bite Bread

Is
Every Syllable at a Force of 60
Pounds, While the Man in Vehe-
ment Oratqry Crashes His. Teeth
With 1OO-POund Blows:
/ Do you know that it is an i'm
possibility to bite the bread that
mother makes?
An absurd question, you reply.
But if you think that you can
thrust your teeth through the parti-
cles of fluffy white bread you make
one of the greatest mistakes of your
| life. Such is one of the latest dis
coveries of science, announced as a
result of a series of tests made to
determine the amount of pressure
exerted by the human jaw in the
process of masticating food.
Do you know that the woman
who participates in the ordinary con-
versation of the gossip fest shuts her
| jaws together with force of so
| pounds every time she utters a syl-
liable, while the man in vehement
oratory makes teeth crash against
teeth with 100 pound blows
DR.. Green Verdeman Black is the
man who does know. He is the dean
| of Northwestern University Dental
School in Chicago. For II years
he has been testing the strength
! of muscles of the human jaw to
ascertain how hard men and women
bite. Of late he has directed his ex
periments to the number of pounds
of pressure exerted by the lower
| iou in tba m a ctioo+iop Of difforoDf
kinds of food.
The Pressure Registered.
The earlier experiments were car
ried on by means of the gnathody-
namometer which DR.. Black invent
ed. This resembles a pair of plyers
about five inches long. The jaws
of the device are held open by ap-
| paratus similar to that of spring,
which is inclosed between what
might be termed the handles of the
plyers. To this apparatus is at
tached a pointer that registers the
number of pounds of pressure ex-
erted on the jaws of the instrument
in closing or partly closing them.
The test with this instrument is
simple. The subject opens his mouth
half or three-quarters of an inch,
enough to admit the insertion Of
the jaws between his teeth, then
bites as hard as he can on the jaws
of the gnathodynamometer, which
are covered with hard rubber for
the protection of the teeth. The
pointer denotes the number of
pounds of pressue exerted, just as
that of a pair of scales denotes the
weight of a pound of sugar at the
custom house since the government
investigation began there.
With a class of six students Pro-
fessor Black obtained results show
ing wide differences in the power Of
the muscles to close the human
jaws. One student registered $50
pounds of pressure, another 1856,
a third 100, the fourth 220 pounds,
the fifth 225, and the sixth $50
pounds. In tests with other classes
there were subjects whose maximum
pressure was as low as 100 and as
high as 800 pounds. One student
brought the jaws of the gnathodyna-
mOmeter together with a snap re-
peatedly. The instrument he used
the only one available at the time,
had a maximum capacity of 275
pounds. The ease and rapidity with
which he closed it convinced Pro-
fessor Black that his jaw muscles
were capable of at least $50 pounds
pressure.
All these tests and many others
of the same kind had a specific OBJ
ject relating to the construction Of
false teeth and the filling of natural
ones. In fact, it was in futherance
of the scientific practice of dentistry
that DR.. Black Investigated the sub
| ject at all, and the same purpose
led him to the study of the press
ure of the jaws in the process of
mastication and conversation.
Impossible to Bite Bread.
Bread, says Professor Black, is
the mots difficult and damaging food
to the teeth. Even with a pressure
of 300 pounds it is impossible to
bite bread. In attempts to bite
bread the teeth are often broken.
Its mastication is made possible by
reason of the fact that the jaws of
man are so fashioned that the teeth
come together with a grinding mo-
ton. There is a scientific reason
| then for breaking bread into small
pieces before attempting to grind it
IN mastication. Even then whether
capable of so or 300 pounds all the
! strength of the jaw muscles, of pres