This section is from the book "Materia Medica Pharmacy, Pharmacology And Therapeutics", by W. Hale White. Also available from Amazon: Materia Medica Pharmacy, Pharmacology And Therapeutics..
Manna. - The concrete, saccharine exudation of Fraxinus Ornus Linne (nat. ord. Oleacea).
Basin of the Mediterranean.
In flattish, somewhat three-edged pieces, occasionally 20 cm. long, and 5 cm. broad, usually smaller; friable; externally yellowish-white, internally white, porous and crystalline; or in fragments of different sizes, brownish-white and somewhat glutinous on the surface, internally white and crystalline: odor honey-like; taste sweet, slightly bitter and faintly acrid.
The chief constituents are - (1) Mannit, C6H8(OH)6, 90 per cent. (2) Glucose. (3) Fraxin, C32H36O20. (4) Mucilage. (5) Resin. Manna is contained in Infusum Sennae Compositum. Dose, 1/2 to 2 oz.; 15. to 60. gm.