26 VEGETABLE DRUGS WITHOUT ORGANIC STRUCTURE. 



Irregular and brownish pieces, collected later in the 

 year, in which tears may be found, constitute the variety 

 of sorts. Often the manna spreads out on the branches 

 and is gathered as flattened pieces, flakes, which vary 

 widely in size. Fat manna is a type of sort manna which 

 is collected late in the year after finer varieties have been 

 utilized. It is darker in color, softer and hygroscopic. 

 It may contain some tears. It is liable to ferment rapidly 

 and break down into a soft, fatty and bitter mass. 



Chemistry. — Mannite, CgH8(0H)g, 25 to 80 percent.; 

 also other sugars, grape sugar, invert sugar, mucilage, 

 dextrin. Fraxin, CieK^gOj^, is stated by Fliickiger to 

 be absent in old manna. Bitter principle, citric acid. 

 Mannite, obtained by crystallization from alcohol, occurs 

 in white rhombic prisms, is soluble in 6.5 parts of water 

 (16° C), melts at 165° C, without change, and can be 

 sublimed. Manna does not reduce Fehling's solution. 

 Mannite is widely distributed in the plant kingdom. 



Other mannas are obtained from a variety of sources. 

 Tamarisk Galltca, by stinging of an insect. Coccus man- 

 nipanis, exudes a clear white manna which is supposed 

 to be the manna eaten by the Hebrews in the wan- 

 derings in the desert. Lecanora esculenta, a lichen, 

 also enjoys a similar reputation. Quercus vallonea and 

 Persica, Alhagi Maurorum, Astragalus adscendens, Salix 

 fragilis and a variety of other plants contain manna. 



Uses. — Demulcent, laxative, and as a food. Dose, 

 q. s. to 30 gm. (i oz.) in solution. 



SACCHARUM. SUGAR. CANE SUGAR. 



The refined sugar obtained from Saccharuni offlcinarum, 

 L., and from various species or varieties of Sorghum 

 (nat. ord. Gramineae) and also from one or more varieties 

 of Beta vulgaris, L. (nat. ord. Chenopodiaceae) . Formula 



The species of Saccharum and of Sorghum are from 



