ore difficult to attack than the shark.

The merchants have to keep a very strict look-out on the divers on their
return to the shore, as frequently when the oyster is in the boat, and
left alive undisturbed for some time, it opens its shell. A pearl may
then easily be discovered, and, by means of a piece of wood, the shell
be prevented from again closing till the diver has an opportunity of
picking out the prize. Sometimes they will even swallow the pearls to
conceal them. As soon as the boats arrive on the shore the oysters are
put in holes or pits dug in the ground to the depth of about two feet,
fenced carefully round to guard them from depredation. Mats are first
spread below them to prevent them touching the earth. Here the oysters
are left to die and rot. As soon as they have passed through a state of
putrefaction and become dry, they can be easily opened without the
danger of injuring the pearl, which might be the case if they were
opened when fresh. The shell is then carefully examined for pearls.
Sometimes one is found in the body of the mollusc itself, but it is
generally in the shell. We afterwards, on going on shore, had a
specimen of the horrid odour which arises from these pits, but the
people who are accustomed to it do not appear to suffer; indeed, we saw
people groping about on the sands where the oyster pits had existed, and
learned that they were seeking for stray oysters, frequently pearls of
some value being thus discovered.

Emily and Grace, as well as Oliver and I, took great interest in
watching the proceedings I have described. I asked Mr Hooker how
pearls come to exist.

"Oh, I have read somewhere," exclaimed Emily, "that they are produced by
a kind of dew which falls from heaven into the salt water, where the
oyster swallows it, when it hardens and forms the beautiful white object
we call a pearl."

"A very poetical notion, Miss Emily," observed Mr Hooker; "but in
reality pearls are identical with the substance which we call
mother-of-pearl, which lines the shell of the oyster. It is, indeed,
the result of disease. When any substance intrudes into the shell the
animal puts forth a viscous liquor, which agglomerates and hardens till
the pearl is formed. It is said, indeed, in some places, that the
divers pierce the shells of the oysters, and thus increase the number of
pearls. It has also been discovered that oysters which have been
pierced by a certain small marine worm have