312 



CONSIDERATION OF CARBON COMPOUNDS. 



boiled with a solution of cupric sulphate in sodium hydrate, to 

 which some tartaric acid has been added. 



2. By precipitating metallic silver, bismuth, and mercury, 

 when compounds of these metals are heated with it in the 

 presence of alkalies. 



3. By easily fermenting when yeast is added to the solution, 

 alcohol and carbon dioxide being formed : 



C 6 H 12 6 = 2C 2 H 5 HO + 2C0 2 . 



Fruit-sugar, C 6 H 12 6 (Levulose). Occurs with glucose in sweet 

 fruits and honey ; it resembles glucose in most chemical and 

 physical properties, but does not crystallize from an aqueous 

 solution ; it may, however, be obtained in white, silky needles 

 from an alcoholic solution. 



Mannitose, C 6 H 12 6 . Obtained by the oxidation of mannite ; 

 it does not crystallize, and resembles grape-sugar. 



Inosite, C 6 H 12 6 (Muscle-sugar). Occurs in various muscular 

 tissues, in the lungs, kidneys, liver, spleen, brain, and blood. 

 Although identical in composition with grape-sugar, inosite 

 differs from the latter in not being fermentable and by not pre- 

 cipitating cuprous oxide from alkaline copper-solutions. 



Cane-sugar, Saccharum, C 12 H 22 U = 342 (Ordinary saccharose, 

 Common sugar, Beet-sugar}. Cane-sugar is found in the juices 

 of many plants, especially in that of the different grasses (sugar- 

 cane), and also in the sap of several forest trees (maple), in the 

 roots, stems, and other parts of various plants (sugar-beet), etc. 

 All plants containing cane-sugar do not contain free organic 

 acids, which latter would convert it into grape-sugar. 



Cane-sugar is manufactured from various plants containing 

 it by crushing them between rollers, expressing the juice, heat- 

 ing and adding to it milk of lime, which precipitates vegetable 

 albuminous matter. The clear liquid is evaporated to the con- 

 sistence of a syrup, which is further purified (refined) by filtering 

 it through bone-black and evaporating the solution in " vacuum 

 pans " to the crystallizing point. 



Cane-sugar forms white, hard, distinctly crystalline granules ; 

 it dissolves in 0.2 part of boiling, in 0.5 part of cold water, 



