282 SUGARS AND [CH. XIII 



of CO 2 : filter, and evaporate down the solution : crystals 

 should be obtained if inulin was present.] 



The alcoholic nitrate is evaporated till the alcohol is 

 completely removed and the residue dissolved in water. 

 The alcohol may be condensed and preserved. 



The solution thus obtained is tested : 



(a) for reducing sugars, glucoses, maltose, 

 (6) for cane-sugar, 

 [(c) for mannite and pentoses.] 

 (a) Test portions with 



(1) Fehling's solution 



(2) Sachsse's 



(3) Barfoed's 



(4 p.c. crystallized cupric acetate + 1 p.c. acetic acid.) 



(4) Phenyl-hydrazin reaction. 



If positive results are obtained with (1) and (2) but 

 not with (3) and not easily with (4) it would indicate 

 that only maltose is present, but this is rarely the case. 



To ascertain whether maltose is present together with 

 glucoses, it is necessary to make roughly quantitative 

 experiments, and it is convenient to arrange these so as 

 also to include the testing for cane-sugar. 



Divide the solution into several equal parts. 



(1) Use one part to determine the original 're- 

 ducing power' of the solution. 



(2) Heat another part with citric acid and ascertain 

 whether the 'reducing power' of the solution has been 

 increased or not by heating with this acid. 



