65 RHAMNUS FRANGULA 



Pharmacopoeia of the United States. But it is official in the German 

 Pharmacopoeia and some other European Pharmacopoeias. 



Collection. The bark should be obtained in the spring from 

 the young trunks and large branches, and carefully dried ; that 

 obtained from the old trunks should not be collected, as it is 

 altogether different in taste and other characters from the younger 

 bark. 



General Characters and Composition. The official Cortex 

 Rhamni Frangulae of the German and other European Pharma- 

 copoeias, is also commonly known as Black Alder, and Alder Buck- 

 thorn bark. It is in small quills, averaging about J a line in 

 thickness. It has a grey, brownish-grey, or blackish-brown colour 

 externally, and is marked by whitish, warty, transversely 

 lengthened protuberances. Internally it is smooth and brownish- 

 yellow. It has a compact, somewhat fibrous texture; and is 

 without any marked odour; but with a pleasant, sweetish taste. 

 Baildon, of Edinburgh, who has recently recommended this 

 bark for medicinal use in Great Britain, says that the bark in 

 small quills should alone be used, as that ' ' taken from the thick 

 part of the trunk is altogether different, and the decoction made 

 from it is nauseous to the taste, whereas that made from the 

 quilled bark is singularly pleasant, with a slight almond or prussic 

 acid flavour." 



Black alder bark has been analysed by Gerber, Binswanger, 

 Buchner, and other chemists. The principal constituents appear to 

 be RJtamnoxanthin or Frangulin ; two resins, one soluble in ether, 

 and the other soluble in alcohol, but insoluble in ether ; a bitter 

 matter also of a resinous nature ; a little tannic acid ; and extractive 

 matter. Ehamnoxanthin is a yellow crystallisable colouring 

 principle. It is accompanied, according to Casselmann, by an 

 amorphous resinous yellow substance, and is most abundant in 

 the bark of the older branches, that of the younger branches con- 

 taining a larger proportion of the resinous constituent. We have 

 no positive evidence of the constituent in which resides the 

 purgative property of the bark, but Binswanger attributed it to 

 the bitter matter of a resinous nature. This bitter matter of 



