THE VOLATILE PART OF PLANTS. V7 
ture of the three sugars with some gum. The mannas of 
Syria and Kurdistan are of similar composition. 
The older observers assumed the presence of glucose in 
the bread grains. Thus Vauquelin found, or thought he 
found, 8.5°|, of this sugar in Odessa wheat. More recent- 
ly, Peligot, Mitscherlich, and Stein have denied the pres- 
ence of : any sugar in these grains. In his work on the 
Cereals and Bread, (Die Getreidearten und das Brod, 
1860,) p. 163, Von Bibra has reinvestigated this question, 
and found in fresh ground wheat, etc.,a sugar having 
some of the characters of saccharose, and others of glucose 
and levulose. It is, therefore, a mixture. ; 
Von Bibra found in the flour.of various grains the following quan- 
tities of sugar. 
PROPORTIONS OF SUGAR IN AIR-DRY FLOUR, BRAN, AND MEAL. * 
Per cent. 
Wheat out cxcsccieccinaancmaaaws one ers 2.33 
ROS NORE ci ciaciavcartiniunnciiaarne oe Ll 
Wheat brattiiss sis essengoass weevemiw venue 4.30 
POH DIAN 5 ssa neces ndsenen dadunananaae on 2.70 
RSS TL OUT esac ciate severe aja svete’ es wracoiate ietatetaee aferainiaie 3.46 
RYO SD EOI o.ce sda sig aisicisiatiseinded tenaisio gs cadvestenaer 1.86 
Barley Meal oicic oss cece ssa snaig eisicnsivcwisisrs a eats viccsre 3.04 
Barley Dratlss ss csavs sincagresxeense eens ena 1.90 
Oat MCA cia sun wisnacanarny Ae anetud wane cenmiere 2.19 
Rice MOUP iscawsisewenceovswasemee ese em weed 0.39 
UG DOU sc cesuaueteentieverrnteasanees 1.30 
Maize meal o.6 one cvorgrerwascnased nesses ee 3.71 
Buckwheat meal...........seceeeeeeeereeee 0.91 a. 
Glucosides.—There occur in the vegetable kingdom a 
large number of bodies, usually bitter in taste, which con- 
tain glucose, or a similar sugar, chemically combined 
with other substances, or yield it on decomposition. 
Tannin, the bitter principle of oak and hemlock bark; 
salicin, from willow bark; phloridzin, from the bark of 
the apple-tree root, and principles contained in jalap, 
scammony, the horse chestnut, and almond, are of this 
kind. The sugar may be obtained from these so-called 
glucosides by heating with dilute acids. 
