CRUDE DRUGS. 6oi 



E. longifolia, E. Maidcni, E. Globulus, E. pulvcrulciita, E. cinerea, 

 E. Stuartiaua, E. Stuartiana var. cordata, E. Morrisii, E. Sinithii 

 and E. sideroxylon. 



UVA URSL RED BEARBERRY. The leaves of Arcto- 

 staphylos Uva-iirsi (Earn. Ericaceae), a procumbent shrub indig- 

 enous to Europe, Asia and the Northern United States and 

 Canada (p. 357). 



Description. Obovate. spatulate, 18 to 30 mm. long, 6 to 10 

 mm. broad; apex obtuse; base acute, tapering; margin entire, 

 slightly revolute ; upper surface dark green, glabrous, finely retic- 

 ulate ; under surface yellowish-green ; petiole about 3 mm. long, 

 slightly pubescent ; texture coriaceous, brittle ; odor slight ; taste 

 slightly bitter, astringent. 



When a solution of vanillin and hydrochloric acid, to which a 

 few drops of fresh ferrous sulphate solution are added, is applied 

 to a section of Uva Ursi a crimson color is produced which dis- 

 tinguishes the drug from its adulterants, with the exception of 

 Vacciiiiujn J'itis-Idcea. It is distinguished from leaves of the 

 latter plant as well as other adulterants by becoming bluish-black 

 with ferrous sulphate. 



Constituents. Two glucosides arbutin and ericolin ; a 

 crystalline, resinous principle ursone ; tannin about 5 per cent. ; 

 gallic acid ; ellagic acid ; a yellow, crystalline coloring principle ; 

 calcium oxalate ; ash about 3 per cent. 



Arbutin forms colorless, bitter needles, which are soluble in 

 water and alcohol, the solutions being colored azure blue upon 

 the addition of an alkali followed by phosphomolybdic acid. It 

 yields on hydrolysis hydroquinone (arctuvin) and methyl hydro- 

 quinone. 



Ericolin is a yellow, hygroscopic, bitter substance, which 

 yields on hydrolysis the volatile oil ericinol. Ursone occurs in 

 tasteless needles insoluble in water and capable of being sublimed. 



Allied Plants. ^Various other species of Arctostaphylos 

 contain principles similar to Uva Ursi. The leaves of trailing arbu- 

 tus {Epigaa re pens) contain ericolin and possibly arbutin. Erico- 

 lin occurs in a number of species of Ledum and Rhododendron, 

 and European huckleberry (Vacciniuiu myrtilhis) , small cranberry 

 {Oxycoccus paJnstris) and heather (Calluna vulgaris), all of 



