A grain of sand gets between the folds of the oyster and its shell and irritates the beast.

In self-defense the oyster covers the sand with a fluid which hardens and forms a pearl." "I've always known that," said Flo, with a toss of her head.
"Yes; but I want you all to bear it in mind, for it will explain a discovery I have made.

Before I get to that, however, I want to say that at one time the island of Ceylon supplied the world with its most famous pearls.

The early Egyptians discovered them there, as well as on the Persian and Indian coasts.

The pearl which Cleopatra is said to have dissolved in wine and swallowed was worth about four hundred thousand dollars in our money; but of course pearls were scarce in her day.