POMEGRANATE 461 



0.5 to 2 mm. in thickness; outer surface yellowish brown, with gray- 

 ish patches of foliaceous lichens, brownish-black apothecia and small 

 lenticels, longitudinally wrinkled; inner surface light yellow or yel- 

 lowish-brown, finely striate, smooth; fracture short, even, phello- 

 derm layer dark green, inner bark light brown, somewhat checkered; 

 odor slight; taste astringent. 



ROOT BARK. Dark brown, with slight longitudinal patches 

 and scales of cork, green phelloderm layer wanting, medullary 

 rays extending nearly to the outer surface. 



INNER STRUCTURE. See Fig. 200. 



Powder. Yellowish-brown to dark greenish-brown; calcium 

 oxalate crystals numerous, chiefly in rosette aggregates, also in 

 rhombohedra, from 0.010 to 0.018 mm. in diameter; starch grains 

 numerous, from 0.002 to 0.010 mm. in diameter; spheroidal, ellip- 

 soidal, bi-convex, polyhedral, or irregular, and single or compound; 

 fragments of whitish cork with strongly lignified walls; stone cells 

 mostly single, occasionally in small groups, the individual cells 0.050 

 to 0.180 mm. in length, the walls being very thick and strongly 

 lamellated; occasional fragments of wood with long slightly lignified 

 wood fibers associated with trachese possessing simple pores; tannin 

 cells having an irregular yellowish-brown amorphous content, pro- 

 ducing a deep blue color with solutions of ferric salts; and occasional 

 parenchymatous cells with marked centripetal thickenings; the pow- 

 der of the root bark is free from chloroplastids; the cork cells are more 

 numerous and the sclerenchymatous cells more irregular in shape. 



Constituents. Four alkaloids to the extent of 1 to 3 per cent in 

 the root bark, but only about half as much in the stem bark. The 

 most important of these alkaloids is pelletierine, the tannate of which 

 is largely used in medicine. Pelletierine (punicine) is a colorless, 

 volatile, liquid alkaloid, which readily absorbs oxygen and becomes 

 dark on exposure to air. Its sulphate is IsBvo-rotatory. Isopelle- 

 tierine (isomeric with pelletierine) is optically inactive and forms an 

 amorphous sulphate. Methylpelletierine somewhat resembles pelle- 

 tierine, but its hydrochloride is dextro-rotatory. Pseudopelletierine 

 (methylgranatonine) occurs in prisms, is optically inactive, and 

 resembles, in its reactions and decomposition products, tropinone. 

 The latter is formed from tropine, a compound which results on the 

 decomposition of most of the solanaceous alkaloids. Granatum also 

 contains 20 to 22 per cent of a mixture of tannins, one of which yields 

 gallic acid and the other ellagic acid. A yellow coloring principle, 

 considerable starch and calcium oxalate are also present in the 

 drug. 



