1911 Encyclopædia Britannica/Manna
|←Mann, Horace||1911 Encyclopædia Britannica, Volume 17
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MANNA, a concrete saccharine exudation obtained by making incisions on the trunk of the flowering or manna ash tree, Fraxinus Ornus. The manna ash is a small tree found in Italy, and extending to Switzerland, South Tirol, Hungary, Greece, Turkey and Asia Minor. It also grows in the islands of Sicily, Corsica and Sardinia. It blossoms early in summer, producing numerous clusters of whitish flowers. At the present day the manna of commerce is collected exclusively in Sicily from cultivated trees, chiefly in the districts around Capaci, Carini, Cinisi and Favarota, small towns 20 to 25 m. W. of Palermo, and in the townships of Geraci, Castelbuono, and other places in the district of Cefalù, 50 to 70 m. E. of Palermo. In the frassinetti or plantations the trees are placed about 7 ft. apart, and after they are eight years old, and the trunk at least 3 in. in diameter, the collection of manna is begun. This operation is performed in July or August during the dry weather, by making transverse incisions 1½ to 2 in. long, and about 1 in. apart, through the bark, one cut being made each day, the first at the bottom of the tree, another directly above the first, and so on. In succeeding years the process is repeated on the untouched sides of the trunk, until the tree has been cut all round and exhausted. It is then cut down, and a young plant arising from the same root takes its place. The finest or flaky manna appears to have been allowed to harden on the stem. A very superior kind, obtained by allowing the juice to encrust pieces of wood or straws inserted in the cuts, is called manna a cannolo. The fragments adhering to the stem, after the finest flakes have been removed are scraped off, and form the small or Tolfa manna of commerce. That which flows from the lower incisions is often collected on tiles or on a concave piece of the prickly pear (Opuntia), but is less crystalline and more glutinous, and is less esteemed.
Manna of good quality dissolves at ordinary temperatures in about 6 parts of water, forming a clear liquid. Its chief constituent is mannite or manna sugar, a hexatomic alcohol, C6H8(OH)6, which likewise occurs, in much smaller quantity, in certain species of the brown seaweed, Fucus, and in plants of several widely separated natural orders. Mannite is obtained by extracting manna with alcohol and crystallizing the solution. The best manna contains 70 to 80%. It crystallizes in shining rhombic prisms from its aqueous solution and as delicate needles from alcohol. Manna possesses mildly laxative properties, and on account of its sweet taste is employed as a mild aperient for children. It is less used in England now than formerly, but is still largely consumed in South America. In Italy mannite is prepared for sale in the shape of small cones resembling loaf sugar in shape, and is frequently prescribed in medicine instead of manna.
The manna of the present day appears to have been unknown before the 15th century, although a mountain in Sicily with the Arabic name Gibelman, i.e. “manna mountain,” appears to point to its collection there during the period that the island was held by the Saracens, 827-1070. In the 16th century it was collected in Calabria, and until recently was produced in the Tuscan Maremma, but none is now brought into commerce from Italy, although the name of Tolfa, a town near Civita Vecchia, is still applied to an inferior variety of the drug.
Various other kinds of manna are known, but none of these has been found to contain mannite. Alhagi manna (Persian and Arabic tar-angubīn, also known as terendschabin) is the produce of Alhagi maurorum, a small, spiny, leguminous plant, growing in Arabia, Asia Minor, Persia, Afghanistan, Baluchistan and northern India. This manna occurs in the form of small, roundish, hard, dry tears, varying from the size of a mustard seed to that of a coriander, of a light-brown colour, sweet taste, and senna-like odour. The spines and pods of the plant are often mixed with it. It is collected near Kandahar and Herat, and imported into India from Cabul and Kandahar. Tamarisk manna (Persian gaz-angubīn, tamarisk honey) exudes in June and July from the slender branches of Tamarix gallica, var. mannifera, in the form of honey-like drops, which, in the cold temperature of the early morning, are found in the solid state. This secretion is caused by the puncture of an insect, Coccus manniparus. In the valleys of the peninsula of Sinai, especially in the Wādy el-Sheikh, this manna (Arabic man) is collected by the Arabs and sold to the monks of St Catherine, who supply it to the pilgrims visiting the convent. It is found also in Persia and the Punjab, but does not appear to be collected in any quantity. This kind of manna seems to be alluded to by Herodotus (vii. 31). Under the same name of gaz-angubīn there are sold commonly in the Persian bazaars round cakes, of which a chief ingredient is a manna obtained to the south-west of Ispahan, in the month of August, by shaking the branches or scraping the stems of Astragalus florulentus and A. adscendens. Shir Khist, a manna known to writers on materia medica in the 16th century, is imported into India from Afghanistan and Turkestan to a limited extent; it is the produce of Cotoneaster nummularia (Rosaceae), and to a less extent of Atraphaxis spinosa (Polygonaceae); it is brought chiefly from Herat.
Oak manna or Gueze-elefi, according to Haussknecht, is collected from the twigs of Quercus Vallonia and Q. persica, on which it is produced by the puncture of an insect during the month of August. This manna occurs in the state of agglutinated tears, and forms an object of some industry among the wandering tribes of Kurdistan. It is collected before sunrise, by shaking the grains of manna on to linen cloths spread out beneath the trees, or by dipping the small branches in hot water and evaporating the solution thus obtained. A substance collected by the inhabitants of Laristan from Pyrus glabra strongly resembles oak manna in appearance.
Australian or Eucalyptus manna is found on the leaves of Eucalyptus viminalis, E. Gunnii, var. rubida, E. pulverulenta, &c. The Lerp manna of Australia is of animal origin.
Briançon manna is met with on the leaves of the common Larch (q.v.), and bide-khecht on those of the willow, Salix fragilis; and a kind of manna was at one time obtained from the cedar.
The manna of the Biblical narrative, notwithstanding the miraculous circumstances which distinguish it from anything now known, answers in its description very closely to the tamarisk manna.
See Bentley and Trimen, Medicinal Plants (1880); Watt, Dictionary of Economic Products of India, under “Manna” (1891). For analyses see A. Ebert, Abst. J.C.S., 1909, 96, p. 176.
- See Bombay Lit. Tr., vol. i. art. 16, for details as to the gazangubīn. A common Persian sweetmeat consists of wheat-flour kneaded with manna into a thick, paste.