NAN'NA, a species of sugar -which exudes from incisions made in the sterns of the manna ash (see Asti), a native of the mountainous parts of southern Europe. Sicily is the chief locality of the manna, and there, in July or August, the collectors make a deep cut through the bark to the wood near the base of the tree with a curved-bladed knife, repeating such incisions daily in different places. always, however, on one side only, and gradually rising until the branches are reached, and then some of the largest are also cut. The following year the other side of the tree is operated upon, and this .alternation gives the bark time to heal. If the weather is warm and favorable the manna begins to ooze out of the cuts slowly, and to harden in lumps or flakes, which are from time to time removed by. the collectors. Manna is a light porous substance, of a yellow ish color, not unlike hardened honey, but harder and drier. There are various qualities known in commerce, according to the time of collection, the goodness of the season, and .other causes. It is chiefly used in medicine, having a gentle purgative effect, which renders it valuable for administration to very young children. It consists principally of a crystallizable sugar called marmite, and an uncrytallizable sugar, which possesses the sweet and purgative properties. There are several other manna-yielding plants besides the ash, especially the manna-bearing eucalyptus of Australia (eucalyptus mannifera), which is non-purgative, and is a favorite sweetmeat with the children of that country.
Small quantities are found on the common larch (larix Europmus), in some districts; this kind is known under the name of ir -tnna of Briancon. Manna is also obtained in minute quantities from various mushrocms, and from the fronds of some sea-vveeds.
The nianna of the Israelites, which they ate during their wanderings in the wilder ness, appears probably, as shown by Ehrenberg in his Symbalce Physicee (Fasc. i. 1823), to have been the saccharine substance called _Mount Sinai manna, which is produced in that region by a shrub, tamarix mannifera, a species of tamarisk (q.v.), from the branches of which it falls to the ground. It does not, however, contain any rnannite, but consists wholly of mucilaginous sugar. The exudation which concretes into this manna is caused by the punctures made in the bark by insects of the genus coccus (C. manniparus), which .sometimes cover the branches. It is a kind of reddish syrup, and is eaten by the Arab and by the monks of Mount Sinai like honey with their bread. It has 'Seen very. generally supposed that the manna of the Jews was produced by a species of ca.mel's thorn (q.v.).