Manna.—Manna. The concrete, saccharine exudation, in flakes, of Fraxinus ornus Linné (Nat. Ord. Oleaceae). Dose, 3 j— oz ij, according to age.

Composition and Properties

Manna has a sweetish, rather mawkish taste; is soluble, when pure, in three parts of cold water, and in its own weight of boiling water. It contains a sugar—manna-sugar or mannite, which constitutes from seventy to eighty per cent of the best specimens of manna. It is said to contain dextrin, or a mucilage having similar reactions, and ether extracts from it in small quantity a slightly acrid, reddish-brown resin, on which the laxative property of manna probably depends.

Actions and Uses

Manna is a very mild laxative, but, when administered alone, is apt to cause griping. It is rather slow in its operation, but is free from irritating qualities, and leaves no unpleasant after-effects. It is most frequently combined with other purgatives—senna chiefly—the operation of which it aids, and at the same time renders less drastic. It is rarely given alone, and only to children and pregnant women. Formerly it was used as a laxative in haemorrhoidal affections.