BUCKTHORN BARK 423 



1 to 7 cells in width, and from 10 to 30 cells in height; the cambium 

 margin is distinctly crenate or undulate due, to the shrinking inward 

 of the tissues at each of the medullary rays; nearly all of the cells, 

 with the exception of the lignified tissues, contain the oxy-methyl- 

 anthraquinones and are colored pinkish-red upon the addition of 

 the solutions of the alkalies. 



Adulterant. The bark of Prunus padus has been used as an 

 adulterant. (Jour. A. Ph. A., 1916, 5, p. 303.) 



Literature. Kraemer, Amer. Jour. Pharm., 1912, p. 385; John- 

 son and Hindman, Ibid., 1914, p. 387; Gathercoal, Jour. A. Ph. A., 

 1915, p. 65. 



FRANGULA. Alder Buckthorn Bark. The dried bark of the 

 stem and branches of Rhamnus Frangula (Fam. Rhamnacese), a 

 shrub indigenous to Europe, northern Africa and central Asia, and 

 naturalized in northern New Jersey and Long Island. The bark is 

 collected in spring and kept at least one year before being used, so 

 as to render inert the irritating and nauseating principles, which are 

 destroyed by a ferment during the curing of the drug. The same 

 results are said to be obtained by heating the bark at 37.7 C. for 

 48 hours. 



Description. In single or double quills, seldom in transversely 

 curved pieces, often crushed and flattened, from 2 to 20 cm. in length, 

 1 to 3 cm. in diameter, bark 0.3 to 1 mm. in thickness; outer surface 

 dark brown or purplish-black, longitudinally wrinkled, with numer- 

 ous lenticels 1 to 5 mm. in length, and with grayish patches of folia- 

 ceous lichens and groups of light brown or brownish-black apothecia, 

 older bark with a brownish, roughened cork ; inner surface yellowish 

 or dark brown, smooth, longitudinally striate, and reddened by solu- 

 tions of the alkalies; fracture short, with projecting bast fibers in 

 inner bark, being somewhat longer and coarser in thick bark; odor 

 slight; taste slightly bitter, astringent and acrid. 



Inner Structure. (Fig. 185.) Periderm of several layers of 

 rectangular brown cork cells, having a purplish-black content, dis- 

 tinguishing it from the cork of Rhamnus Purshianus which is reddish- 

 brown; primary cortex of thin-walled, starch-bearing parenchyma 

 and cells containing either a yellowish- or purplish-brown amorphous 

 substance, or numerous rosette aggregates of calcium oxalate from 

 0.010 to 0.025 mm. in diameter; inner bark with bast fibers in narrow, 

 interrupted rows, having thick, strongly lignified, yellowish walls 

 and narrow lumina, each group being surrounded by a layer of crystal 

 fibers, in which the prismatic crystals of calcium oxalate vary from 

 0.007 to 0.015 mm. in diameter; medullary rays 1 to 2 cells in width, 



