CH. XIl] GLUCOSIDES. 271 



Qualitative tests for Phloroglucin. . 



[Where a woody tissue has been extracted, phloroglucin 

 should be tested for in the aqueous solution obtained from 

 the alcohol extract as described above. 



Shake a portion of aqueous solution with ether, sepa- 

 rate the ether layer and evaporate off the ether, take up 

 the residue with water. 



Test portions of the neutral aqueous solution so ob- 

 tained with 



(1) Ferric chloride. 



Deep violet colour shows phloroglucin. 



(2) Freshly cut pine wood and hydrochloric acid. 

 Reddish-violet colour shows phloroglucin. 



(For further tests for Phloroglucin see Beilstein, 2nd 

 ed. vol. II. Phloroglucin.) 



If phloroglucin is present the whole of the aqueous 

 solution may be shaken with ether : the lower layer drawn 

 off and warmed (to expel ether) can then be used for 

 testing for tannins, etc.] 



Removal of Tannins before examining for 

 Sugars. 



As explained above all vegetable tannins do not 

 behave in the same way to reagents, excepting perhaps to 

 gelatin and lead acetate ; it is therefore advisable to try 

 the reactions of a small portion of the solution before 

 deciding which method to adopt for the removal of the 

 tannins. 



The methods may be tried in the following order 



