The Washington times. [volume] (Washington [D.C.]) 1902-1939, 1916-04-04

" lREFL1ES and phosphorescent
- bacteria are not the only vital
substances which emit light. II
has been claimed recently by
spanish scientist that certain tissues
OF man, when grown In an incubator
IN the way Dr.. Alexis Carrel, Of the
Rockefeller Institute, first discovered,
emit mild glow in the dark.
Dr. iJbric Dahlgren, professor of biol
ogy AZ Princeton University, has Just
completed an Investigation which
proves that an immense variety of diff
ferent animals produce powerful lights
from the living fabric.
Even sDonRes alive on the bed OF the
ocean may exhibit luminosity. A tubful
OF dredgings from the bottom of the
Bay OF Naples was found to glow for
hours. Luminous worms and animal-
cules were distributed through the can
aus or the sponges and partly account
for the light. Sponges. Indeed, proba-
bly, emit no light OF their own.
certain worms-"coelenterata, as sa-
wants call them-give forth light. The
skins OF these animals contain tissues
which are analogous to the lightning
bugs abdominal tissues.
Som. OF the Oddities.
The capacity or function of light pro-
duction Is found only In the epidermis
OF the coelenterates. There Is no COM
plete or even surface wholly given over
to tho production of light. The Right
producing areas are scattered between
others that are non-light-prod
Freely swimming medusae or jelly
fish. as well as those attached to rocks
beneath the sea. are luminous. The
number OF species which produce light
Is large. ana their distribution is very
wide.
The common jelly fish or "sea-nettle"
In perhaps the best known of the, coel-
entcrates. II swims by a series of
rhythmic contractions of its umbrella"
most medusae do likewise
When this creature is lazily swimming
In It's home In the sea or in an aquarium
with plenty OF fresh sea water 1t gives
no light at all. Almost any irritation
or stimulant. however. such as mineral
acids. ammonia, or sharp touch,
causes II to show a light.
Under such circumstances, according
to Prof. Dahlgren and other investiga-
to cover the outer surface of the UNI
brclla. the arms and tentacles. The
light is greenish in color. such as APP
pears in an X-ray bulb OF incomplete
vacuum. The light lasts for several
minutes and then dies down very slow
ly.
A slight contact Of the finger or a
glass rod with the outer surface OF the
jelly-fish. causes q spot of light at the
point touched. II then spreads out and
partially covers the bell-shaped surface
Sometimes the light appears in lines
and streaks or In patches
A strange fact Is that the Illuminated
surface. however gently II Is touched
leaves the lighting material attached 70
the fingers. which II continues to shine
for d time.
One Hundred Per Cent Light.
II you strike the surface OF these ami
mas with moderate firmness while tho
creature is at rest and not alight. and
withdraw your finger instantly before
the luminosity appears, no light VIII
be seen on the fingers -
This proves that the vital Hight stuff
has not yet been thrown out OF the tbs.
sue which produces II. Moreover. u
the outer structures are scraped of
they will illuminate. bat the fabric
beneath them Will remain dark.
Experiments ,speh as these OF Prof
Dahigren show that light created by
those animals 1s'the result of bringing
the glandular substance or principle
called luciferiBeo tnto contact with the
free oxygen in sea water or air, as the
luciferine is expelled from the tissues
which make and store IL.
Many different kinds OF plants and