"Branch Mollusca," Conseil said, "class Acephala, order Testacea."

"Correct, my scholarly Conseil. Now then, those Testacea capable of producing pearls include rainbow abalone, turbo snails, giant clams, and saltwater scallops--briefly, all those that secrete mother-of-pearl, in other words, that blue, azure, violet, or white substance lining the insides of their valves."

"Are mussels included too?" the Canadian asked.

"Yes! The mussels of certain streams in Scotland, Wales, Ireland, Saxony, Bohemia, and France."

"Good!" the Canadian replied. "From now on we'll pay closer attention to 'em."

"But," I went on, "for secreting pearls, the ideal mollusk is the pearl oyster Meleagrina margaritifera, that valuable shellfish. Pearls result simply from mother-of-pearl solidifying into a globular shape. Either they stick to the oyster's shell, or they become embedded in the creature's folds. On the valves a pearl sticks fast; on the flesh it lies loose. But its nucleus is always some small, hard object, say a sterile egg or a grain of sand, around which the mother-of-pearl is deposited in thin, concentric layers over several years in succession."

"Can one find several pearls in the same oyster?" Conseil asked.

"Yes, my boy. There are some shellfish that turn into real jewel coffers. They even mention one oyster, about which I remain dubious, that supposedly contained at least 150 sharks."

"150 sharks!" Ned Land yelped.

"Did I say sharks?" I exclaimed hastily. "I meant 150 pearls. Sharks wouldn't make sense."

"Indeed," Conseil said. "But will master now tell us how one goes about extracting these pearls?"

"One proceeds in several ways, and often when pearls stick to the valves, fishermen even pull them loose with pliers. But usually the shellfish are spread out on mats made from the esparto grass that covers the beaches. Thus they die in the open air, and by the end of ten days they've rotted sufficiently. Next they're immersed in huge tanks of salt water, then they're opened up and washed. At this point the sorters begin their twofold task. First they remove the layers of mother-of-pearl, which are known in the industry by the names legitimate silver, bastard white, or bastard black, and these are shipped out in cases weighing 125 to 150 kilograms. Then they remove the oyster's meaty tissue, boil it, and finally strain it, in order to extract even the smallest pearls."

"Do the prices of these pearls differ depending on their size?" Conseil asked.

"Not only on their size," I replied, "but also according to their shape, their water--in other words, their color--and their orient-- in other words, that dappled, shimmering glow that makes them so delightful to the eye. The finest pearls are called virgin pearls, or paragons; they form in isolation within the mollusk's tissue. They're white, often opaque but sometimes of opalescent transparency, and usually spherical or pear-shaped. The spherical ones are made into bracelets; the pear-shaped ones into earrings, and since they're the most valuable, they're priced individually. The other pearls that stick to the oyster's shell are more erratically shaped and are priced by weight. Finally, classed in the lowest order, the smallest pearls are known by the name seed pearls; they're priced by the measuring cup and are used mainly in the creation of embroidery for church vestments."

"But it must be a long, hard job, sorting out these pearls by size," the Canadian said.

"No, my friend. That task is performed with eleven strainers, or sieves, that are pierced with different numbers of holes. Those pearls staying in the strainers with twenty to eighty holes are in the first order. Those not slipping through the sieves pierced with 100 to 800 holes are in the second order. Finally, those pearls for which one uses strainers pierced with 900 to 1,000 holes make up the seed pearls."

"How ingenious," Conseil said, "to reduce dividing and classifying pearls to a mechanical operation. And could master tell us the profits brought in by harvesting these banks of pearl oysters?"

"According to Sirr's book," I replied, "these Ceylon fisheries are farmed annually for a total profit of 3,000,000 man-eaters."

"Francs!" Conseil rebuked.

"Yes, francs! 3,000,000 francs!" I went on. "But I don't think these fisheries bring in the returns they once did. Similarly, the Central American fisheries used to make an annual profit of 4,000,000 francs during the reign of King Charles V, but now they bring in only two-thirds of that amount. All in all, it's estimated that 9,000,000 francs is the current yearly return for the whole pearl-harvesting industry."

"But," Conseil asked, "haven't certain famous pearls been quoted at extremely high prices?"

"Yes, my boy. They say Julius Caesar gave Servilia a pearl worth 120,000 francs in our currency."