226 WOODS 



Substitutes, &c. Commercial guaiacum wood turnings frequently 

 contain the sap wood as well as chips of other woods. These may 

 be detected by their floating in brine and by the amount of alcoholic 

 extract which should not be less than 22 per cent. 



QUASSIA WOOD 



(Lignum Quassiae) 



Source, &c. The official quassiawood is derived from Picrcena 

 excelsa, Lindley (N.O. Simarubece) , a tree of moderate size, common 

 on the plains and lower mountains of Jamaica. 



Quassia wood was introduced into medicine about the middle of 

 the eighteenth century, but was then obtained from Quassia amara, 

 Linne, a smaller tree than Picrcena excelsa, and indigenous to the 

 north of South America, whence its usual, distinctive name of Surinam 

 quassia. The wood of P. excelsa was found to possess the same 

 properties, and has been substituted for it in England, but Surinam 

 quassia remains official on the Continent. 



The trunks and larger branches with the bark attached are ex- 

 ported in logs and billets about 1J to 2 metres in length and 20 to 

 30 cm. in diameter. 



Description. The logs of Jamaica quassia wood are commonly 

 covered with a thin, dark grey or nearly black bark. The wood 

 is pale yellow in colour, light, rather dense, and easily split. When 

 the smoothed transverse section is moistened and examined with 

 a lens numerous, narrow medullary rays can be seen traversing some- 

 what irregular concentric rings. The latter are not annual rings, 

 but are produced by the distribution, in more or less concentric zones, 

 of bands of parenchyma (false annual rings) . The vessels are usually 

 in groups of two or three, and frequently extend from one medullary 

 ray to the next. 



Not unfrequently dark grey patches are visible in the wood ; they 

 are caused by a fungus, the dark hyphae of which penetrate the wood 

 through the cells of the medullary rays and wood parenchyma. 



The wood has no odour, but the taste is purely and intensely bitter. 

 For use in pharmacy it is usually cut across the grain by large knives 

 like chisels and the chips kiln-dried to prevent them becoming mouldy, 

 as the wood often contains much moisture. 



The student should observe 



(a) The pale colour and intensely bitter taste of the drug, 



(b) The distribution of the vessels. 



Constituents. According to Massute (1890), Jamaica quassia 

 wood contains two closely allied crystalline bitter principles, 

 a-picrasmin, C 35 H 46 O 10 (m.pt. 204), and ft-picrasmin, C 36 H 48 O 10 



