158 PLANT AND ORGANIC CHEMISTRY 



a weighed porcelain-covered crucible, and the percentage of 

 ash calculated. 



Weight of precipitate by stronger alcohol yielded 1.70 per cent. 



" " ash yielded 0.34 " 



Carbhydrates. 



The nitrate and wash-alcohol from the gum precipitate were 

 concentrated at a low temperature, and the residue was mixed 

 with four volumes of stronger alcohol. The precipitate was 

 rapidly filtered off, and the percentage of carbhydrates calcu- 

 lated gravimetrically in the usual way, from the amount of 

 cupric oxide reduced from Fehling's solution. It yielded 2.75 

 per cent. 



Carbhydrate Filtrate. 



A portion, representing a certain volume of the aqueous 

 extract, of the carbhydrate filtrate was evaporated, dried, and 

 weighed. It yielded 7.65 per cent, of the total solids of the 

 aqueous extract residue. A known weight of the carbhydrate 

 filtrate residue was dissolved in water and heated over a water 

 bath with Fehling's solution, and the amount of glucose pre- 

 sent estimated gravimetrically from the weight of the cupric 

 oxide. It was estimated as 4.47 per cent. Another portion of 

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

 hol. A precipitate formed on cooling, which was collected on 

 a weighed filter, dried, and weighed. It yielded 1.98 per cent. 

 The 83 per cent, alcohol precipitate was identified as saponin 

 by the usual tests. The carbhydrate filtrate residue was preci- 

 pitated by acetate of lead and the precipitate examined qual- 

 itatively for organic acids. The lead precipitate was decom- 

 posed by sulphuretted hydrogen and filtered, and the filtrate 

 concentrated over a water bath, and mixed with lime-water 

 until turbid. The turbidity did not clear on adding dilute acetic 

 acid. 



The aqueous extract was examined for tannin, and with 

 negative results. Calcium oxalate was present. 



