Most of the Placuna pearls are calcined and are used with areca-nuts and betel-pepper leaves in a very popular masticatory, one of the “seven sisters of sleep,” which is to the Hindu what opium is to the Chinaman, or tobacco to the American or European. The hard white areca-nut (_Areca Catechu_) is about the size and shape of a hen’s egg. Three or four thousand tons of the small, tender nuts are annually shipped from Ceylon to India for this masticatory, which is chewed by a hundred million persons. After boiling in water, pellets of them are placed in a leaf of the betel-pepper (_Piper betle_) with a small quantity of lime made from pearls or shells, according to the desired quality and value of product. It is credited with hardening the gums, sweetening the breath, aiding digestion, and stimulating the nervous system like coffee or tobacco; its most visible effect is tingeing the saliva and blackening the teeth, which is far from attractive, especially in an otherwise beautiful woman. A more recent use for these Placuna pearls is as an ingredient in a proprietary face powder and enamel, which is marketed in Europe. It is not alone the Orientals that have found medicinal virtues in pearls. Even in Europe they have occupied a prominent place in materia medica, especially during the Middle Ages when a knowledge of the occult properties of gems was an important branch of learning. Indeed, they could scarcely have been overlooked by people who at one time or another swallowed pretty much everything, from dried snake’s eyes to the filings of a murderer’s irons, in their quest for the unusual and costly with which to relieve and comfort themselves. During the Middle Ages in Europe, writers who gave attention to pearls, as well as to other gems, treated almost exclusively of their reputed efficacy in magic and in medicine; and most of the accounts from the ninth to the fourteenth century seem wholly without scientific value, and at times reach the climax of extravagance and absurdity in their claims for the wonderful potency of the gem. Albertus Magnus, the Dominican scholar born in Germany in the twelfth century, wrote that pearls were used in mental diseases, in affections of the heart, in hemorrhages, and dysentery.[360] The “Lapidario” of Alfonso X of Castile (1221–1284), called “The Wise,” the father of the Spanish language, states: The pearl is most excellent in the medicinal art, for it is of great help in palpitation of the heart, and for those who are sad or timid, and in every sickness which is caused by melancholia, because it purifies the blood, clears it and removes all its impurities. Therefore, the physicians put them in their medicine and lectuaries, with which they cure these infirmities, and give them to be swallowed. They also make powders of them, which are applied to the eyes; because they clear the sight wonderfully, strengthen the nerves and dry up the moisture which enters the eyes.[361]