Page:The New International Encyclopædia 1st ed. v. 12.djvu/906

MANNA. stituents, as reported by many investigators, aro mannite CO to 'JO per cent.," glucose, Jimcilage, fraxin. resin, etc. In addition to its value in medicine, m.inna lias been extensively used for food, its value for this purpose depending upon the carbohydrates present.

In addition to that produced by various species of ash, manna or substances resembling it are excreted by many other species of plants. In Australia various species of Eucalyptus produce what is called manna or lerp. This saccharine substance is said to be without the laxative piop- erties of true manna and is eaten as food. Sim- ilar substances are obtained in Australia from the tea tree ( Leplospcnnum acDjiariiim). sandal-wood (Myoporum plati/carpum). and Australian blue grass (Andropofton ri)i)u(lntiis) . During a fam- ine in India a manna-like substance was exuded in suflicient abundance from a species of bamboo {Drudrocalamus sirirliix) to form an important food supply in some districts. It did not contain any mannite, the principal characteristic of true manna. Similar substances are obtained from the common larch of Europe ( Larix Europwa) the substance being known as Briancon manna; from Quercus rallnnrn, called Armenian manna; Persian manna from Alhagi cnntcloniin, the camel's thorn; tamarisa manna from Tamarix mannifera, believed by some to have been the source of the manna of the Israelites, while others attril)ute it to a lichen. Lccnnorn esculrnla : American manna, from the sugar pine IPiinifi Lambeiti<inn) : California manna, believed to be deposited from Phnifimite.t communis, etc. Some insects, as Laviniis me}Iifici(s, secrete a similar material. All of tliesc saccharine substances are usually groujied together as false manna. They contain as their principal constituent melitose or melezitose, but no mannite. A large number of plants do yield small ouantities of mannite in ad- dition to that found in the excretions of the ashes. For a discussion of their chemical com- position, consult Tollens, Handbuch der h'ohlen- hi/drate (Breslau, 1805).