64 RHAMNUS CATHARTICUS 



our supplies are chiefly obtained ; but the collectors commonly 

 prefer to supply the juice expressed by themselves rather than the 

 ripe fruit, and as this juice is generally, as shown by Umney, 

 largely diluted with water, the supply of the ripe fruit ought to 

 be insisted on. 



General Characters and Composition of the Juice. The fresh juice 

 is green, and has a very unpleasant odour, and a bitterish, some- 

 what acrid, disagreeable taste. Its specific gravity, according to 

 Umney, should be 1*070 to 1*080. By keeping, its colour 

 gradually changes to red, and its specific gravity, from a deposi- 

 tion of solid matter, is reduced to T035. 



Buckthorn fruit and juice have been repeatedly analysed, and 

 several colouring principles have been obtained from them and 

 similar parts of other species of Rhamnus, but at present we have no 

 satisfactory evidence of the source of their active purgative proper- 

 ties, although Winckler believes that this resides in a principle 

 which he has termed cathartin. A yellow crystalline principle 

 has also been indicated by Fleury, who named it rhamnine, and 

 more recently this has been examined by Lefort and other chemists, 

 but with very conflicting results. 



Medical Properties and Uses. Buckthorn juice is a powerful 

 hydragogue cathartic, but as its action is frequently attended with 

 severe griping, nausea, and thirst, it is but very little used at the 

 present day, except as a domestic remedy and in veterinary 

 practice. It is generally prescribed in the form of syrup for 

 children. 



Formerly buckthorn juice was frequently employed in cases 

 where an active cathartic was required, as in gout and rheu- 

 matism, obstinate constipation, and dropsical affections. Lately, 

 the bark of Rhamnus Frangula, Alder Buckthorn, which has 

 been long employed in Germany, has been highly recom- 

 mended for use in this country as being a valuable cathartic 

 without causing any of the distressing effects so frequently found 

 to accompany the action of buckthorn juice. (See Rhamnus 

 Frangula.) 



The pigment, so well known as sap-green, the vert de vessie of 



