Domestic Encyclopædia (1802)/Manna

MANNA, the juice obtained from several species of ash, particularly the Fraxinus rotundifolia and Ornus, growing in Italy and Sicily. When naturally concreted on the tree, this juice is called manna in the tear: but, if it exude on straws or chips of wood affixed to the tree for that purpose, it is called canulated, or flaky manna.

This drug, commonly sold in the shops, is obtained by making incisions in the tree, after the spontaneous exudation has ceased: it consists of larger masses, and is of a deeper red than that which flows without wounding the tree.

The best Calabrian manna is imported in oblong, light, friable flakes, or pieces, of a whitish, or pale yellow shade, and somewhat transparent. The inferior sorts are moist, unctuous, and of a darker colour.

Manna is a mild and agreeable laxative, which may be safely administered to children and the aged; though, in some constitutions, it is apt to induce flatulency, and to distend the bowels; but this inconvenience may be remedied by the addition of a little cinnamon water, or other warm aromatic. The dose for children is, according to their age, from one to three drams; and for adults, one ounce, or one ounce and a half: as, however, its operation, when taken by itself, is very mild, and sometimes imperceptible, it is generally given in laxative mineral waters, or combined with salts, senna, rhubarb, or similar aperient medicines.

Lastly, we can speak from experience, that manna is one of the most useful demulcents in the humid asthma, and similar pituitous as well as inflammatory affections of the breast; that it beneficially promotes expectoration, and is of peculiar service in the second stage of the small-pox, or during the suppuration of the pustules.