Pearls were used in medicine until the eighteenth century, when it began to be suspected that chalk had the same effect. The tiniest pearls, known as pearl seeds, ground to a fine powder, were prescribed as an absorbent, antacid, and cordial. This powder was also used, says Pomet, “by ladies of quality to give a lustre and beauty to the face.” It was superseded before long by Lemery’s magistery of bismuth, which, however, retained the name of pearl white. Pomet further states that a magistery of pearl was made (apparently by quacks) by combining the ground pearl with acids; an arcanum, spirits, flowers, and tinctures were also prepared and credited with marvellous virtues, “to pick fools’ pockets.” Pearls, writes Jean de Renou (1607), “are greatly cordial and rejoice the heart. The alchemists consequently make a liquor of pearls, which they pretend is a marvellous cure for many maladies. More often than not, however, their pretended liquor is nothing but smoke, vanity, and quackery. I knew a barber in this city of Paris who was sent for by a patient to apply two leeches, and who had the impudence to demand six crowns of gold for his service. He declared that he had fed those leeches for an entire month on the liquor of pearls.” It is on record that Pope Clement VII took 40,000 ducats’ worth of pearls and other precious stones with unicorn’s horn within fourteen days. (See Mrs. Henry Cust’s “Gentlemen Errant.”) Emeralds had a great reputation, especially on account of their moral attributes. They were cold in an extra first degree, so cold that they became emblems of chastity, and curious tales of their powers in controlling the passions were told. Moses Maimonides, a famous Jew who lived in Egypt in the twelfth century, in a treatise he wrote by command of the Caliph as a concise guide in cases of venomous bites or poisons generally, declared that emeralds were the supreme cure. They might be laid on the stomach or held in the mouth or 9 grains of the powdered stone might be taken in wine. But recognising that emeralds were not always handy when the need arose, Moses names a number of more ordinary remedies.