Note 142 — Chapter XI · PEARLS.

All this theory is, of course, totally imaginary. The pearl itself is nothing else but a diversion, so to speak, of the juices, whose duty it is to line the interior of the shell, to thicken and so amplify it; and consequently, the pearl is the result of some malady. It is possible for them to be found in all shell-fish; but they have no beauty in them, unless the interior of the shell, or, as we call it, the mother-of-pearl, is lustrous and beautiful itself. Hence the finest of them come from the east, and are furnished by the kind of bivalve, called by Linnæus, “Mytilus margaritiferus,” which has the most beautiful mother-of-pearl in the interior that is known. The parts of the Indian sea which are mentioned by Pliny, are those in which the pearl oyster is still found in the greatest abundance.