QUASSIA. 149 



Schultze's maceration fluid is an invaluable help in the 

 study of the isolated parts of the wood and should be 

 constantly employed. 



QUASSIA. 



The wood of Picrcsna excelsa (Swartz), Lindley. Jam- 

 aica. 



In the German Pharmacopoeia both Jamaica (P. ex- 

 celsa) and Surinam {Quassia amara) Quassia are men- 

 tioned. In billets of various sizes, dense, tough, of 

 medium hardness, porous, with a minute pith and narrow 

 medullary rays, inodorous and intensely bitter. In the 

 shop it is met with in the form of chips or raspings of a 

 yellowish-white color. 



Description. — The bark is 0.5 to i.o cm. wide, and 

 breaks off quite readily. It is of a dark color and 

 'shows on cross-section a radial irregular structure. Be- 

 neath the end is a narrow, grayish layer, beneath which 

 is the main body of the wood, showing a number of ducts 

 and medullary rays. Central pith in the interior. The 

 cells of the periderm are oblong, the outer ones being 

 stained dark-brown. The parenchyma of the outer 

 layer is rich in calcium oxalate crystals. 



Jamaica. — Elements large; medullary rays two to 

 five, lying close to vessels. Single calcium oxalate 

 crystals in woody parenchyma. Pores elongated radially 

 (crystal cells) ; more bordered pores. 



The phloem contains bast fibres which are well marked, 

 cambiform cells, and sieve tubes which are somewhat 

 contorted and irregular. 



The medullary rays are some two or three cells in 

 width, contain starch, and widen out very markedly in 

 the phloem portion of the bundle. 



The xylem contains: Vessels, tracheids, woody fibres; 

 woody parenchyma and simple parenchyma. 



The vessels are large, two or three collected and 



