Evening star. [volume] (Washington, D.C.) 1854-1972, 1928-11-30
OySTERSTEW PEARL
IS DECLARED MYTH.
Edible BivaIve Incapable of
Producing One of Value,
il Scientists Say.

The frequent reports Of fine pearls
ruined in oyster stews are unfounded
for the edible oyster is physically in
capable of producing pearl OF value
Oysters may be loosely claSSed into two
groups, the pearl producing and the
non-pearl producing species
First of all, what are pearls? The
ancients believed pearls to be drops of
dew or tears of the angels that had fall
len into the open shell of the oyster.
They would have been closer the truth
had they referred them to tears of tor
ture, for pearls are due to an accident
Detailing the oyster which forms them.
The lodgrnent of grain of sand or of
some parasite in the heshy tissue of the
animal eXcites the pearl formation, for
the oyster, in order to free itself from
the irritating object, SecreteS about it
a shelly capsule, the nature of which
depends entirely upon the species of
oyster producing 1t.
Pearl Oyster Described.
The pearl oyster, for instance, will
cover the foreign object, layer upon
layer, with calcium carbonate and chit
inou5 matter heavily laden with So
luton of pearly nacre, thus producing
a fine pearl The non-pearly or edible
oyster. on the other hand will cover the
object with a case of calcium carbonate
and chitinous matter which is entirely
devoid of the solution of pearly nacre
necessary to the production of fine
pearl. The absence of the pearly nacre
in the edible oyster is purely phys
biological condition peculiar to that Spe-
cieS of oyster and is in no way mtiu-
enced by geographic environment. The
so-called pearls sometimes found In ed
ible oysters are therefore nothing more
than dark-colored shelly concretions
which are interesting purely as curiosi-
ties and have no value from a jewelry
standpoint.
Clam Shell Is Producer.
Although most fine pearls come from
the pearly oyster, the unio margarifer,
common river-muSsel, and other bivalve
shells produce fine pearls. These clam
shells are found in freSh-water streams
the world over, being especially abund-
ant in the streams of the United States.
The oyster or oriental pearl is probably
finer than any but the very exceptional
freShwater pearls, yet some OF the nm
est of the latter frequently approach
the oriental in quality.
1t is a popular belief that pearls de-
teriorate very readily, yet the observ-
ance of few simple rules is sufficient
to care for them properly. Pearls
should always be kept in as even tenn
perature as possible, for they expand
and contract on exposure to heat and
cold. When they are not in use, they
should be carefully wiped and stored
in places where the atmosphere is
relatively pure and even. The compo-
sition of the pearl is 90 per cent car
Donate of lime, per cent organic
matter and 2 per cent water. It IS
R,nl &1asc nfI
water be retained in the pearl. In
order that this be accomplished pearls
should be kept in a container lined
with fine quality of oil silk rather than
in receptacle lined with absorbent
material.
Calcium Carbonate a Destroyer.
Calcium carbonate, of which the pearl
is largely composed, is easily attacked
by strong acids, and II allowed 70
come in contact with certain Of the
stronger acids, the pearl will dissolve
almost Immediately. The weaker acids
such as vinegar and lemon juice, on
the other hand. even though they
would impair the luSter very readily,
win not dissolve pearl completely for
several days, so that it is altogether |
doubtful if the story OF Cleopatra and
her pearl, which she Is alleged TO have
dissolved in vinegar and swallowed In
order to win wager with Antony, is
founded on truth.
Many women religiously wear their
pearls next to their skin day and night
under the impression that the pearl Is
thus preserved. This is, in part at least,
a mistaken idea. Queen EliZabeth's
earrings, the four great pearls which
hang beneath the arch in the Kings
state crown, have probably never been
worn next to the skin. Although Queen
Elizabeth died 800 years ago they are
still in a good state of preservation
and may remain so for several GEN.
turtles more. They are kept in per-
fectly alright compartment and at an
even temperature.