2 76 MANNA. 
ART. LXXV. — MANNA . 
By A. Leuchtweiss. 
Manna has been examined by Fourcroy and Vauquelin, 
Thenard, and Buchholz. The latter found in the best 
manna : — 
Mannite, 60 
Mucous sugar and coloring matter, - 5.5 
Gummy extractive, - - - - 0.8 
Gum, - 1.5 
A glutinous matter, - - - - 0.2 
Water, 30 
Thenard describes manna as containing mannite, 10 per 
cent, of fermentable sugar, and a nauseous uncrystallisable 
substance ; the latter may be separated by means of aether. 
To obtain pure mannite^ the sugar must be separated by 
fermentation, the filtered solution evaporated, the residue 
dissolved in boiling alcohol, of 0.833 specific gravity, when 
the mannite separates on cooling. By washing with cold 
spirit, it is obtained beautifully pure and white. Manna 
yields in this way from 32 to 42 per cent, of mannite. 
The analysis of three specimens gave : 
i. ii. in. 
Water - - - 11.6 13 11.1 
Insoluble constituents (impurities) 0.4 0.9 3.2 
Sugar - - - 9.1 10.3 15 
Mannite - - - 42.6 37.6 32 
Mucilage resin, an acid and nitroge- 
nous matter - 40 40.S 42.1 
Ash - - - 1.3 1.9 .19 
100 100 100 
The ashes of manna consist of potash, lime, magnesia, 
peroxide of iron ; phosphoric, muriatic, sulphuric acids, in 
minute quantities; and alumina and silica, probably from 
impurities. 
