396 RUBIACE^E 



branched, closely annulated with thickened, incomplete rings, and 

 usually exhibiting transverse fissures with vertical sides, through the 

 bark; fracture short, the very thick, easily separable bark whitish, 

 usually resinous, the thin, tough wood yellowish-white, without 

 vessels; odor very slight, peculiar, the dust sternutatory; taste bitter 

 and nauseous, somewhat acrid. It is stated by Rusby that the 

 Rio variety has almost ceased to arrive in the market, the Carthagena 

 variety being supplied. This is now mostly what is known as 

 Panama Ipecac. 



Carthagena ipecac is of a dull gray color, thicker, less frequently 

 and sharply crooked, and lacks the constrictions characteristic of 

 Rio ipecac, although it bears the annular thickenings, or merging 



FIG. 227. Ipecac Cross-section of root, (is diam.) A, Cork. B, Parenchyma of cortex. 

 C, Xylem. (Photomicrograph.) 



annulae. The thick bark, on cross-section, has rather a grayish color, 

 the medullary rays are more prominent and more numerous. 



STRUCTURE. The thin outer layer of cork cells contains a brownish-red 

 deposit, thought by some to be emetine in combination with ipecac- 

 uanhic acid. The thick inner cortical layer consists of starchy 

 parenchyma, free from medullary rays, but containing a circle of 

 stone cells filled with calcium oxalate crystals. Transverse sections 

 show rather a small layer of cork cells, a thick cortical portion con- 

 sisting of parenchyma, loaded with starch and rich in alkaloid. The 

 woody portion, radiate, contains little or no alkaloid. 

 Powder. Characteristic elements: See Part iv, Chap. I, B-. 



CONSTITUENTS. Emetine (i to 2 per cent.), cephaeline, psycho trine, and 

 a peculiar tannic acid called ipecacuanhic or cephaelic acid, starch, 

 resin, etc. The active principles exist only in the bark of the root, 



