Mason — Preliminary Notes on the Carbohydrates of the Musci. 15 

 ''A) Qualitative Work. 



(1) IDENTIFICATION OF SUGARS. 



An aqueous solution of the sugars, freed from tannin, gums, chlorophyll, 

 &c, is prepared in the usual way. 



A suitable quantity of the material to be examined is immersed in boiling 

 alcohol for five minutes, in order to destroy the enzymes. The alcohol is 

 decanted off and replaced by distilled water. After twelve hours' extraction 

 the water is filtered off and added to the alcoholic extract. The alcohol is 

 distilled off, and the chlorophyll thrown out of solution. Basic lead acetate is 

 added to precipitate the tannin and gums, which are removed from the 

 extract. 



The excess of lead is neutralized by sodium carbonate ; and the deleaded 

 extract concentrated and placed aside for examination. For this the following 

 tests have been employed. 



Reducing Sugar. — For the detection of reducing sugars freshly made 

 Fehling solution is quite satisfactory. 



Hexoses. — A. small quantity of the extract is added to a solution of two 

 parts phenylhydrazine chloride and three parts sodium acetate in twenty 

 parts of water. On heating for half-an-hour a yellow needle-shaped osazone 

 separates from the mixture in the presence of certain hexose sugars, viz., 

 c^-glucose, ^-fructose. 



Dextrose [d-glucose). — A small quantity of the extract is added to an 

 alcoholic solution of diphenylhydrazine. In the presence of glucose the 

 colourless diphenylhydrazones separate from the mixture after several days. 



Levulose {d-fructose). — A small quantity of the extract is added to an 

 alcoholic solution of methylphenylhydrazine, to which a few drops of acetic 

 acid have been added. The mixture is heated for ten minutes, and then 

 placed aside. After a couple of weeks the red-yellow osazone appears in the 

 mixture, if levulose is present. As a confirmatory test for levulose Pinoff s 

 ammonium molybdate solution has been found quite satisfactory. 



Maltose. — The greater solubility of the crystals of maltose phenylosazone 

 in hot water offers a means of separating it from the less soluble osazones of 

 other sugars, yet the influence of impurities modifies its character so greatly 

 that this means of identification is often rendered inconclusive. 



The increase in the amount of copper reduced after treatment with 

 takadiastase is undoubtedly the most reliable means of identifying maltose. 



Sucrose. — Sucrose is easily identified by means of the use of invertase. 

 The study of the enzymes offers a means of checking the results derived by 

 the above methods. 



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