It has been recently declared by a dealer in precious stones that though diamonds and other stones can be very well imitated, yet pearls cannot be. This is hardly correct, as artificial pearls so well made as to defy detection by the casual glance of any but a professional expert are common enough. Who does not know the pathetic story by the greatest of French writers, Guy de Maupassant, of the wife of a poor Government clerk, who borrowed a necklace from another lady to wear at a reception at the “Ministry”? She lost the necklace (I forget whether it was of pearls or of diamonds, or both); but she and her husband were too proud to confess the fact, and purchased another necklace exactly like the lost one, for a sum the outlay of which reduced them for the rest of their lives to a state of penury and social exile. They returned the new necklace in place of the lost one without a word, and accepted their fate. By chance, the poor ruined lady, fifteen years afterwards, met her old friend, who had long since passed from her acquaintance, together with other prosperous people. Moved by her former friend’s kind reception, she related the true history of the pearl necklace of long ago. “Great heavens!” exclaimed the prosperous lady. “The necklace I lent you was made with imitation gems! It was not worth five pounds!” Too late! Nothing now could give back to the high-minded, self-respecting little couple the lost years of youth passed in privation and bitterness. 34. _The Nature of Pearls_ Pearls have been lately studied by zoologists, and their true history made known. They are a disease, caused, like so many other diseases, by an infecting parasite. It is common knowledge that they are found much as we see them in jewellery, as little lustrous spheres embedded in the soft bodies of various shellfish, such as mussels, oysters, and even some kinds of whelks. They are not found in the shellfish like crabs and lobsters, called Crustacea, but only in those like snails, clams and oysters, called Mollusca. Pink pearls are found in some kinds of pink-shelled whelks. A pearl-mussel or pearl-oyster has a pearly lining to its shell, which is always being laid down layer by layer by the surface of the mussel’s or oyster’s body, where it rests in contact with the shell, which consequently increases in thickness. If a grain of sand or a little fish gets in between the shell and the soft body of its maker, it rapidly is coated over with a layer of pearl, and so a pearly boss or lump is produced, projecting on the inner face of the shell, and forming part of it. These are called “blister-pearls,” and are very beautiful, though of little value, since they are not complete all round, but merely knobs of the general “mother-of-pearl” surface. These blister-pearls can be produced artificially by introducing a hard body between the shell and the living oyster or mussel.