296 



RHAMNACE^E 



dish principle, exists in the old bark; these develop by age. Two 

 products are obtained from frangulin by hydrolysis emodin, CisHio-. 

 Og, and rhamnose, C 6 Hi 2 O 5 . Frangula-emodin differs from the rhu- 

 barb-emodin in melting-point, and in some color reactions. Senna and 

 aloes also contain an isomeric emodin. (See Rhamnus Purshiana.) 

 Ash, not exceeding 6 per cent. 



FIG! 168. Rhamnus frangula Branch. 



Preparation of Frangulin. Macerate the bark for four days in carbon disul- 

 phide. Evaporate; exhaust residue with alcohol; evaporate alcoholic solution 

 to dryness; crystallize from ethereal solution. Forms sublimable yellow crys- 

 tals; becomes purple when treated with alkalies. Dyes cotton, silk, wool, etc., 

 yellow. 



ACTION AND USES. A mild laxative or cathartic, acting like senna and 

 often used in its stead. Dose: ^ to 2 dr. (2 to 8 Gm.). 



OFFICIAL PREPARATION. 



Fluidextractum Frangulae, ....... .Dose: 



to 2 fl. dr. (1.3 to 8 mils). 



