220 MATER i A MEDIC A AND THERAPEUTICS. 



Characters. Deep red by reflected, green by transmitted, 

 light. 



Composition. Buckthorn juice contains an active prin- 

 ciple, rhamnicin, probably identical with cathartic acid, the 

 purgative glucoside of senna and rhubarb. 



Preparation. 

 Syrupus Bha-ynT". Dose, 1 fl.dr. 



ACTION AND USES. 



Buckthorn is an active cathartic, naturally resembling 

 senna and rhubarb. It is very seldom employed. 



Rhamnus Frangula. (Not Officinal.) The 

 bark of the Rhamnus frangula, or Black Alder. Im- 

 ported from Holland. 



Characters. Quills half a line thick, with a warty greyish- 

 brown exterior ; nearly inodorous ; taste sweetish bitter. 



Composition. Black Alder contains an active crystalline 

 principle, emodin, also found in Eheum (see page 317). 



Non-officinal Preparations. 



A Fluid Extract, and Lozenges. 

 Dose. 1 to 4 fl.dr. of the former. 



ACTION AND USES. 



Rhamnus frangula is a certain and pleasant aperient, 

 without griping or severe cathartic action, used in chronic con- 

 stipation, and especially suitable for children. 



Rhamnus Purshiana. (Not Officinal) The 

 bark of Gascara sagrada, or .Rhamnus purshiana. 

 From the North Pacific coast. 



Composition. A crystalline and various resinoid bodies 

 have been obtained from caseara, which requires to be further 

 investigated. 



Non-officinal Preparations. 



A Fluid Extract, and a Cordial. 



