Willmar tribune. [volume] (Willmar, Minn.) 1895-1931, 1897-10-05
TANNING OF THE SKIN.
How Light and Heat Affect the Human
! Cufielo.

sclehtlnc Investigations nave developed
mary interesting facts. Contrary to
the former popular belief that sunburn
was due to the heat of the sun, it has
now been shown that it is the suns light
chiefly which affects the skin. That
severe sunburn may be produced with
out heat has been proved by the fact
that persons exposed to strong sunlight
on the tops of mountains at extremely
low temperatures have been burned
just as if they had undergone the suns
heat as well. Alpine travellers and those
who have taken long journeys over the
Show have had the experience of being
painfully burned by the reflected light
from the white, glittering surface, and
sunburn from reflections on the water
is equally we'll known. That heat alone
does not produce the effect is clear from
many evidences. Persons exposed to
the high temperatures which prevail in
tie firerooms of ocean steamers, in deep
mines and other places, do not become
tanned and burned in the same manner
as those who work in the sun.
According to the present theory, then.
sunburn, or tan, is produced by the &C
tinic rays of the suns light-that is,
those rays which possess the power of
affecting chemically certain substances
upon which they fall. In photography
it is we'll known that the blue or violet
rays of light have far more effect upon
the sensitive plate than the red rays,
and recent experiments have tended to
show that this is also true regarding
the rays end the human skin. The ex
periments have been conducted with
differently colored glass screens, placed
between the light and the skin. Red
glass, according to the principles of
physics, allows the red light rays to
pass through it freely, while rejecting
the complementary blue rays. In the
same way, blue glass admits the blue or
violet rays and excludes the red. Thus,
as the red rays have been shown to have
the least chemical power, any red SUBJ
stance which screened the skin, allow
ing only the comparatively harmless
the most effective protection against
sunburn.
A rather amusing but well authentic
Gated instance is a proof of this. A
woman who was travelling on foot with
a party of tourists wore a waist which
had alternate broad stripes of white
and red. After long exposure to the
sunlight she found that she had been
burned through the material of the
waist, and, to her utter establishment,
that the burn was in well-marked
stripes-intense under the white bars
OF cloth, and scarcely perceptible under
the red ones. white, which allows all
rays to pass through it, is practically
like no screen at ally This experience
would indicate that red wells, for in
stance, would be the best to protect the
face, and that the old-fashioned blue
wells worn a few years ago were of the
| most undesirable color possible.
That part of the skin which receives
the chemical action of the light rays SO
as to produce sunburn, tan, or freckles
is the pigment, or coloring matter. This
varies greatly in constituencies in diff
ferent persons, not always being gov
erned by the complexion, although, as
rule, blends and red-haired persons
arc more subject to sunburn than
others. Just why some people burn red,
while others freckle or tan, does not
seem to be definitely known. Doctors
| usually say that the difference is due
merely to the varying qualities of skins.
Generally, after months of exposure
to the sun, any skin becomes hardened
to its effects, takes on permanent
brown or bronze color, and is not
changed thereafter by any amount of
additional exposure. But there are ex-
| captions to this rule. There is an old
! fisherman down on the Great South bay,
who, though he has lived in the open air
all his life, is continually being burned
afresh by the suns rays. Year after
year his face peels and becomes sore
several times in a season. The skin
has never been able to accustom itself
to the burning sunlight.
''The darkening of the pigment in the
skin,'' said physician, els an effort of
| nature to interpose defense against
the inflaming light rays. The darker
the surface upon which they fall the
more difficult is it for them to pass
| through and injure the sensitive parts
beneath. Sunburn, however, does not
| do any real harm to the skin; in fact,
the light and air are rather beneficial
than otherwise, although the first eff
feet, if there is swelling and extreme
heat, is rather painful
When asked why wind often seemed
to produce burn as readily as sunlight,
| the doctor said:
''The wind, by irritating the skin, pro-
! duces certain amount of congestion,
and thus predisposes to the effect of the
sunlight. When the skin is even slight
~ congested it will burn quickly, even
in rather weak light. In the same
way heat also, by congesting the skin,
is predisposing cause to sunburn,
though not the direct cause, which is
to be found in the light"
In connection with the subject of the
| effect of light upon the skin it is inter
esting to recall the many cases in which
| the ;Roentgen rays have caused some
thing almost precisely like sunburn.
Persons avhO have oxnoSo1 +he;v ~