156 PLANT AND ORGANIC CHEMISTRY 



chloride and sodium chloride solutions did not precipitate 

 it. The gum was boiled with dilute acid, and heated over a' 

 water bath with Fehling's solution, which it reduced. A few 

 drops of hydrochloric acid and stronger alcohol were mixed 

 with the concentrated gum solution for the separation of ara- 

 bin. It was not separated. 



Carbhydrates. 



The nitrate and wash alcohol from the gum precipitate 

 were mixed, and evaporated to a syrupy consistency at a tem- 

 perature of 70 to 80 C. The concentrated solution was treated 

 with four volumes of stronger alcohol, and the resulting pre- 

 cipitate of carbhydrates rapidly filtered off. It was soluble in 

 water. It was not precipitated from aqueous solution by basic 

 acetate of lead, and by this means it was distinguished from 

 vegetable mucilage. The carbhydrates were boiled with dilute 

 acid, and the solution was rendered alkaline, and heated over 

 a water bath with Fehling's solution. The latter was reduced. 

 The percentage of carbhydrates as estimated, amounted to 

 0.2 per cent. An aqueous carbhydrate solution was mixed with 

 a solution of barium in 40 per cent, alcohol. It yielded no pre- 

 cipitate. 



Carbhydrate Filtrate. 



The carbhydrate filtrate was concentrated at a low tempera- 

 ture in a current of carbonic acid until the alcohol was dis- 

 sipated. The residue was examined for glucose, organic acids, 

 saponin, and tannin. Traces of glucose were detected quali- 

 tatively by Fehling's test; the amount of cuprous oxide pre- 

 sent was too small to estimate gravimetrically. A part of the 

 carbhydrate filtrate residue was boiled with 83 per cent, alco- 

 hol, and filtered while hot. On cooling, a precipitate formed. 

 This precipitate was identified as saponin. It was almost in- 

 soluble in stronger alcohol. Baryta- water precipitated it from 

 aqueous solution. Its aqueous solutions frothed on shaking. 

 When agitated with chloroform and on evaporating the chloro- 

 form solution, a light-colored residue was obtained. A few 

 drops of concentrated sulphuric acid mixed with it gave a red- 



