Evening star., 1941-11-01
Of Stors, Men
And Atoms
Notebook Of Science Progress
In Laboratory. Field
And Study
BIZ Thomas r. Henrv.

BIZ Thomas r. Henry.
Tooth decay, the most widespread
disease Of civilization, may be prevented,
or greatly decreased, by very minute
amounts of the element huorine In
drinking water.
This is a conclusion Of United States
Public Health Service workers from .
crucial experiment in an Arkansas min
ing town, results Of which have just
been announced.
It has long been known that a disease
known as mottled enamel, causing un-
slightly brownish spots on the teeth, ap-
peared only in communities where there
was relatively large amount of this
element In the water. One of the worst
places in the United States was the town
of Bauxite. Ark. Practically every adult
had the disease. 1t was almost entirely
absent from the neighboring town Of
Benton. Bauxite got its water from deep
wells. Benton got its supply from the
| fluorine-free Saline River which flowed
nearby.
IN 1928 Bauxite started drawing its
water from the same river and no new
cases of mottled enamel developed This
was not an unmixed blessing. The town
had been one Of the freest communities
in the United States from dental decay.
Now this condition began to show up in
the spotlessly white teeth of the younger
generation.
Meanwhile cooperative studies OF the
Public Health Service and the Univer-
sity of Michigan had shown that very
minute amounts of fluorine in water
seemed" to inhibit decay in the teeth
of school children. There was a lively
dispute about it. Some claimed that the
element got into the teeth themselves
and hardened them Others maintained
that the inhibition was due to the action
of fluorine in the mouth on a micro
organism in saliva which plays leading
role in dental carries
The Bauxite experiment seems to set
tie this point. The inhabitants fell into
three groups. All those approaching
middle age, who had used the fluorine
water for at least II years, still had mot
tied enamel of moderate or severe
type. But the II years during which
they had drunk fluorine-free water had
not increased the amount OF tooth decay.
1t remained less than half that of the
people Of Benton in the same age group.
The second group was made up of
those born few years before the change
OF water was made and who were now
in middle or late adolescence when tooth
decay is likely to be most rampant. They
had no mottled enamel. Apparently they
had not used the fuorine water long
enough to cause this condition. Their
teeth, while not quite so good as those
OF their parents, were much better than
those of comparable groups Of young
people in other communities.
Third were those born after the
change was made and who never had
drank any f1uorine water. They showed
by far the highest incidence of dental
decay, although they had been exposed
to risk Of it for the shortest period.
Thus, the Public Health Service investi-
gators point out, it seems clear that the
element produces q permanent change,
probably by getting into the teeth them
selves.
How this can be taken advantage OF
In practice still is not clear. Fluorine
in any considerable quantities is poison.
The Bauxite well water had a concentra-
ton of IA parts Of the element to Il
million parts of water, and this is about
the maximum mixture that could be i'm
bided safely. Even this would produce
mottled enamel in few years.
Among the suggestions has been that
very minute amounts of the element
be placed in city water supplies. This
has been done for the past 20 years with
the equally poisonous element, iodine, a
deficiency of which in the water of large
sections of the United States used to
cause goitre. This might save millions
annually in dental bills but, Public
Health Service doctors say, much expert
mental work on the physiological effects
of the element would be required before
any such recommendation could be made.
At present drinking water over the
greater part of the United States is
enamel disease is known only from
few communities, mostly in the South.
- + X
Giant SQulrrelS faSt-runnlng rnl-
noceri and fantastic slothlike creature
of 100000 900 years ago are represented in
nearly two tons of fossilized bones Sc
cured in Southern Wyoming this sum-
mer by DR.. Charles L. Gain, Smithson-
ian Institution paleontologist.
DR.. Gain carried out his excavations
In the Bridger Basin, classic hunting
ground for mammal fossils from the
Middle Eocene period in geological his
| tory. This was the time when ancestral
lines of many extant animals were diff
| Terminating into something like their
| present forms.
Much of the material secured by DR..
Gain remains unidentified, but it is
fairly representative of the strange crea-
lures of the age. Notable is an incom-
plete skeleton of the stylinodont, an
animal very similar to sloth in general
appearance. It belonged, however, to an
entirely different line Of development
| and is not ancestrally related either to
the present-day sloths Of South America
or to the great sloth which survived in
North America through the last Ice Ages.
The line Of the stylinodont became en-
tirely extinct. It's remains are among
the rarest of all Eocene fossils and the
find is regarded as probably the best Of
the summer. The remains found by DR..
| Gain already has been partly excavated
by some pot hunters" and abandoned.