154 COMPOSITION OF THE BODY. 



To a portion of the solution add caustic soda. No color is ob- 

 tained with iodine. In solution dextrins are not precipitated by 

 basic lead acetate alone, but by basic lead acetate and ammonia. 



A portion of the solution of the alcoholic precipitate may here 

 be tested for inulin. 



Add to some of the solution in a test-tube a few drops of strong 

 hydrochloric acid and boil. Cool the solution and add a few 

 drops of phloroglucin in alcohol. The presence of inulin is indi- 

 cated by a yellow-brown color. 



To another part of the solution add baryta water until no 

 further precipitate is formed. After washing the precipitate, de- 

 compose it in water with a current of CO 2 , filter and evaporate 

 the filtrate ; if inulin was present crystals should be obtained. 



After the precipitation of the dextrins the alcoholic filtrate 

 would probably contain most of the sugars, possibly glucoses, 

 maltose and cane-sugar. This filtrate should be evaporated to 

 remove all the alcohol and the residue dissolved in water. Test 

 portions of this solution with the following reagents : 



1. Fehling's solution. Fehling's solution should be first 

 tested by boiling a little in a test-tube. If red cuprous oxide is 

 not precipitated by this treatment the solution is still good. Add 

 some of the extract and boil. A greenish coloration followed 

 possibly by a yellow precipitate, which finally turns red, indicates 

 the presence of a reducing sugar. 



Fehling's solution should be kept in two parts to ensure its 

 preservation. Solution A should consist of 34.64 grams of pure 

 cupric sulphate dissolved in 500 cc. of distilled water. Solution 

 B should be made up of 173 grams of Rochelle salts (sodio- 

 potassium tartrate) in 100 cc. of pure caustic soda sp. gr. 1.34, 

 and water to 500 cc. When ready to use mix equal volumes of 

 A and B. 



2, Barfoed's solution. This solution gives a precipitate of red 

 cuprous oxide on boiling, if dextrose is present. Lactose, maltose, 

 cane-sugar, and dextrin when heated with it for a short time give 

 no reaction. 



