CH. XIIl] QUANTITATIVE. 285 



chloric acid, and the distillate tested for furfurol (furfur- 

 aldehyde) by the colour reaction with aniline acetate. 



[BROWN and MORRIS did not find pentoses in leaves of 

 TropOBolum : but compare the paper by DE CHALMOT, 

 Amer. Chem. J. xv. (1893).] 



Quantitative. 



It is not generally necessary to estimate dextrins, but 

 if necessary the precipitate by alcohol may be estimated 

 by the method described for starch ; or it may be dissolved 

 in water, dried at 110 C., and weighed as anhydrous dex- 

 trins. 



Estimation of glucoses, maltose, cane-sugar. 



For an account of the volumetric methods of esti- 

 mating the reducing power of solutions by Fehling's, 

 Pavy-Fehling's, or Sachsse's solutions, consult SUTTON, 

 Volumetric Analysis, pp. 259 269, where full details are 

 given for preparing the standard solutions, and performing 

 the operations. 



[For standardising these solutions, pure anhydrous 

 glucose (dextrose) can now be obtained from dealers in 

 pure chemical reagents.] 



Divide the solution in which the sugars are to be 

 determined into three equal parts ; 100 c.c. each is 

 generally convenient. 



(1) Use one part for the determination of the original 

 'reducing power' of the solution. 



(2) Use another part for the determination of the 

 'reducing power' after 'inversion' with citric acid. 



(3) Use another part for the determination of the 



