MANNITE ( from manna), A hexahydric alcohol found in the manna from Prtbrinus ()runs (Linni) , which grows in the basin of the Mediterranean. It was discovered hr that manna by Proust in 1806 and may be readily ex tracted from it with hot water or boiling weak alcohol. It is found also in many other vegetable produets. including onions, celery. a sparagus, many fungi. etc.; and it has been prepared artificially from several varieties of sugar, such as lievulose, dextrose, and mannose, by reduction with sodium amalgam. Vice versa. j,y careful oxidation of mannite with nitric acid a mixture of sugars may be obtained. to which the name mannitose is sometimes applied. Marmite is produced also when eane-smga• undergoes fermentation. It may be obtained either in the form of rhombic prisms. or in the form of silky needle-like crystals; it. melts at 165-166° C., and it is readily soluble in hot water or alcohol, but only moderately sal uble in cold water, and searcely solulde at all in cold alcohol and in ether. Its pure aqueous solu
tion has a very slight action on polarized light: the action is, however, greatly increased by the presence of free alkali as well as of certain salts. especially borax. Mannite is eapable of existence in three (list in et modifications. having the same chemical constitution and therefore much the same properties. yet differing from one another in their power of rotating the plane of polarized light. The chemical constitution of marmite is represented by the formula CIT,(0II) . CH (On CH(01I) . CH(OH) . CH(OH) CH (mu. The hexahydric alcohol .sor•bite found in plums, apples, pears, cherries, and other fruits, and the hexahydric alcohol dulcitc found in \ladagasear manna, are in many respects very similar to //infinite.