![]() ![]() These are small thickened inclusion cysts on the palate, but can also occur on the gums or palate. Spearing (1976).What are those hard white bumps on a baby’s gums?ĭepending on the size and spread over the jaws, there are two options: Willard, ed., Medieval English Verse and Prose (1948) studies by I. Bibliographyįor translations of the first, fourth, and fifth poems and for bibliography, see R. Erkenwald, is attributed by some authorities to the same anonymous author. If single authorship is accepted, the artistry displayed in this poem and in The Pearl make the so-called Pearl-poet in some respects a rival to Chaucer. Sir Gawain and the Green Knight, the fourth poem, which relates a fabulous adventure of Gawain, is perhaps the most brilliantly conceived of all Arthurian romances. The second and third poems, Cleanness (or Purity) and Patience, are homiletic poems on those virtues. The Pearl is usually explained as an elegy for the poet's young daughter in an allegorical vision of singular beauty he sees her as a maiden in paradise and becomes reconciled to her death. Pearl, The, one of four Middle English alliterative poems, all contained in a manuscript of c.1400, composed in the West Midland dialect, almost certainly by the same anonymous author, who flourished c.1370–1390. Inferior Chinese pearls are crushed and used in cosmetics and medicines. Although many freshwater pearls are irregular oblong “rice pearls,” round and near-round pearls are also produced. The quantity of freshwater pearls produced far exceeds that of saltwater pearls, and freshwater pearls are also significantly cheaper. To produce freshwater pearls, a small piece of mantle tissue from one mussel is placed into a second mussel shell beads and small seed pearls are also used. ![]() The oysters are then placed in cages that are suspended into sheltered bays for the period of time (up to 4 years) required for pearl formation.įreshwater pearl cultivation is dominated by the Chinese. These pearls are commonly produced by placing a small mother-of-pearl bead enclosed in a piece of mantle tissue in the body of the oyster. Nearly all of the world's supply of cultured saltwater pearls is produced by the Japanese, who have perfected the techniques of saltwater pearl cultivation. In ancient times the Red Sea was an important source. ![]() Other important sources are the coasts of India, China, Japan, Australia, the Sulu Archipelago, various Pacific islands, Venezuela, and Central America, and the rivers of Europe and North America. The largest natural pearl center is the Persian Gulf, which is said to produce the finest saltwater pearls. They are very soft and are injured by acids and heat as organic products, they are subject to decay.Ĭommercially valuable pearls are obtained from pearl oysters (especially of the genus Pinctada) and from freshwater pearl mussels (especially of the genus Hyriopsis). Pearls are not cut or polished like other gems. The iridescence which some pearls display is caused by the overlapping of successive layers, which breaks up light falling on the surface. The unique luster, or orient, of pearls depends upon the reflection and refraction of light from the translucent layers and is finer in proportion as the layers are thinner and more numerous. ![]() Black pearls, because of their rarity, are often highly valued. The best pearls are usually white, sometimes with a creamy or pinkish tinge, but may be tinted with yellow, green, blue, brown, or black. Pearls found attached to the inner surface of the shell are known as blister pearls. Pearls may be rice-shaped, round, pear-shaped, button-shaped, or irregular (baroque) and are valued in that order. The pearl is built up of layers of aragonite or calcite (crystalline forms of calcium carbonate) held together by conchiolin (a horny organic substance) its composition is identical to that of the mother-of-pearl, or nacre, that forms the interior layer of the mollusk shell. It is secreted by the epithelial cells of the mantle, a curtain of tissue between the shell and body mass, and is deposited in successive layers around an irritating object-usually a parasite in the case of natural pearls-that gets caught in the soft tissue of the mollusk. Pearl, hard, rounded secretion formed inside the shell of certain mollusks, used as a gem. Above Jackson, Miss., the Pearl's largest city, is Ross Barnett Reservoir, one of the state's chief water-storage areas. and flowing S to Lake Borgne, an inlet of the Gulf of Mexico its lower section (116 mi/187 km) forms the Miss.-La. Pearl, river, 485 mi (781 km) long, rising in E Miss. ![]()
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