The midland journal. (Rising Sun, Md.) 1885-1947, 1904-09-02
SECRET OF ORIENT PEARL
DISCOVERED TO. BE MERELY SEP.
ULcHRES OF DEAD PARASITES.

GtSSON ~ SEr
ULcHRES OF DEAD PARASITES.
The Gu.f Of Manaar, on the Coast Of
ceyIon, is the Chief Source-Fished
Up by Native Divers-Tombs OF
Baby Tape Worms.
For more than 1000 years the Gulf
of Manaar, on the northwest coast OF
Ceylon, has been noted as the chief
source of Orient pearls, which are
found in the bodies of pearl oysters
(Margaritifera vulgaris), more truly
described, however, as pearl mussels
The mollusks are fished up by ma
tive divers, though recourse will prob
ably be made to dredging in the flu
ture. The alarming decline in this
important fishery, the proceeds OF
which, amounting to hundreds OF
thousands of rupees annually, have
long been an important asset in the
revenue of the Ceylon government,
recently resulted In Prof Herdman OF
Liverpool being sent out to ascertain
the cause, and, if possible. to suggest
remedy.
The first volume of his report mas
just appeared, and the beneficial re.
suit Of his valuable suggestions is
already being felt. Mr.. James Hor-
nell, a we'll known naturalist. has
been associated with Prof. Herdman
in the matter, and is continuing the
work under the auspices of the Colo,
NAL Government. The most interest
ing outcome Of the whole thing is
the fascinating story which these ex
perts tell us about the mode of origin
Of oysters tears" Mr. Hornell has
just ascertained the facts which make
the story complete.
For nearly half a century it mas
been known that river pearls, which
once were the object of important
British fisheries, are caused by the
irritation set up by parasitic worms.
and forty years ago Kelaart proved
that this is also true of the marine
pearls Of Ceylon. But it has been re-
served for Herdman and Hornell to
work out in detail the story of the
parasite infesting the pearl oyster
adding one more romance to the fairy
tale book of modern science.
Living in Indian seas is voracious
stingray (Trygon), the intestines OF
which afford food and lodging to Pc
culiar little tape worm (Teirarhyn.
chus) This unwe:come guest holds
on for dear life to the lining of the
intestine by means of two suckers
and our long hooked tubes, project.
ing from it's head. AS in tape worms
generally, the hind end is made UP
of series of fiat joints, within which
innumerable eggs are developed The
ripe joints pass out of the body OF
the fish, and from the eggs minute
free-swimming embryos hatch out.
Some of these pass between the
shells of pearl oysters, burrow into
the bodies of the unfortunate inmates.
and there develop heads. But many
other things must happen IL they are
to get the chance of growing into
adult worms. One of the hereditary
foes of pearl oysters is the rough
skinned trigger fish (balistes), which 4
feeds on the sluggish bivalves, easily
crushing their hard shells with its
powerful chisel-ended teeth. If one
of these fishes happens to devour an
infested oyster the little parasites
bore through the walls of its .stom.
ach and imbed themselves in its flesh.
making it "measily." But the para,
site has yet to reach the interior OF
stingray before 1t can become adult.
and the transfer is often effected, for
the trigger fish Is favorite item in
the bill of fare of the stranger ray.
But what has all this to do with
pearls? Here Is - aanswer. Many
Of the juvenile tape worms that infest
the oyster die. and then become a
source Of irritation. To allay the tick.
ling, layer after layer of pearly sub
stance is formed around them. and in
due course we have pearls. Long-in.
tested oysters, of course, yield the
finest The economic bearing of these
facts is clear. Stingrays and trigger
fishes alike must be carefully pre-
served" otherwise the tape worm |
will become extinct, and then no
pearls, or. at least. none of the best
sort. Some varieties are very posi-
bly, caused by parasites of other
kinds. And small, inferior pearls may
be formed round sand grains or mi
mute. hard particles due to infiam-
disease. In ignorance Of the
facts related, 1t was proposed not
lclg ago to wage war a poutrance |
against the trigger fishes because they |
1evour pearl oysters If the step had
been taken the government pocket
would have been sorely depleted. So.
litter all, natural history has its uses
or practical men," and 1t is a pity
hat our government does not gen.
,rously endow scientific research in
his important subject.
The secret of the Orient pearl, as
low revealed, will suggest some GU.
'ious reflections to society beauties.
Or haua .nan Soma of tA,air