27 
THE CEYLON PEAEL INDUCING WORM. 
A BRIEF REVIEW OF THE WORK DONE TO DATE. 
By T. SOUTHWELL, A.R.C.Sc. (Lond.), F.L.S., F.Z.S. 
Deputy Director of Fisheries for Bengal. Late Scientific Adviser 
and Inspector of Pearl Banks to The Ceylon Company 
of Pearl Fishers Limited. 
I PROPOSE in this paper reviewing very briefly the work which has 
been done on the Ceylon pearl-inducing worm, during the last ten 
years. This is particularly appropriate at the present time as the Pearl 
Banks—which have been under lease to a London Syndicate, who have 
spared no pains or money in the investigation—may at an early date 
revert back to the Government. It remains to be seen to what 
extent the Ceylon Government will profit by these investigations, and 
whether they will continue the work with the vigour which has 
characterised the Company’s administration. 
Most people are familiar with the ancient and poetical beliefs 
regarding pearls, viz. that they were the tears of Nereids, or con¬ 
solidated drops of dew, or caused by lightning flashes. Later on these 
romantic beliefs were superseded by others which attributed the origin 
of pearls to the irritating effect caused by the presence of grains of 
sand, and other foreign bodies, in the tissues of the oyster. 
Kelaart, as a result of a few years work on the spot, about the year 
1858, observed that pearls were intimately connected with the presence 
of “worms” in the oyster, and in 1894 Thurston confirmed Kelaart’s 
results and identified the worm as the larva of a Platyhelminth. 
These results represent all that was actually known regarding the 
pearl-inducing worm up to the year 1902. 
About this time the intermittent nature of the Pearl Fisheries 
seriously occupied the attention of the Colonial Government, as these 
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