Pearls are the product of certain species of shell-fish, both marine and
fluvial. The cause and manner of their formation have not even yet been
completely ascertained. They do not constitute any part or organ of the
creature that contains them. They are not found in every shell, nor of
the same size and shape in any two. They are eccentric and accidental,
probably also morbid excrescences, thrown out by some individuals of the
species in irregular forms and at uncertain times. They probably owe
their origin to the presence of some minute foreign substance within the
shell, which is distasteful to its occupant. Not being able to cast out
the intruder, the feeble but diligent inhabitant covers it with a sort
of saliva, which hardens over it into a substance similar in consistency
and sheen to the interior surface of its own shell. The act of covering
a base substance of any shape with gold or silver by the process of
electrotype is in human art an analogous operation. When the material,
distilled in imperceptibly minute portions from the living mollusc, has
chemically agglomerated round the original kernel, the pearl is made.
The creature having covered the irritant atom with a coating at once
hard and smooth, can now endure with equanimity its presence within the
shell. Thus unconsciously it manufactures those indestructible and much
coveted jewels, for the sake of which its own life is sought and taken
by man.

In modern times pearl fishing has become a business, and is prosecuted
on a great scale in several far separated regions. Perhaps the increase
of production, through superior methods and instruments, may, here as
elsewhere, have contributed to depreciate the value of the article.[23]

[23] I have been informed by a British merchant who, under license
from the government of India, conducts the pearl fishing in the Bay
of Kuratchee, that the method pursued is to bring the shells to
shore as they are brought up from the bottom of the sea until a
considerable quantity has been accumulated, disposed in a series of
small contiguous heaps, and that then the men stand round the heaps,
open the shells, and search for the pearls. So much loss accrues
from the dishonesty of the men and the facility of secreting a
treasure that lies in such a small bulk, that the proprietor of the
fishing has had under consideration a suggestion to sell the heaps
of shells by auction to the natives, and permit them