152 PLANT ORGANS OR PARTS OF PLANTS. 



both forms of quassia is quassin. Besides this, there is 

 some resin and starch. The wood of the Surinam variety 

 yields 3.6 per cent, and its bark 17.8 per cent, ash, while 

 the figures for the Jamaica variety are respectively 7.8 

 and 9.8 per cent. 



HiEMATOXYLON. LOGWOOD. 



The heart wood of Hcematoxylon Campechianum, Linne 

 (nat. ord. LeguminoscB). 



This is a tropical tree, 8 to 1 2 metres (24 to 36 feet) high, 

 a native of Central America, but since 1715 cultivated in 

 Jamaica and other West Indian islands. The trunks and 

 branches of the trees at least ten years old are collected, 

 and the yellowish sap wood removed. 



Description. — The wood comes in logs about three feet 

 long and weighing about 50 kilograms. It is bluish 

 black or greenish externally, fibrous, splitting easily, the 

 fresh surfaces shining red brown. The wood also often 

 occurs in commerce in the form of chips or powder which 

 have been exposed to air and moisture and have assumed 

 a greenish-black color. In this state it should not be 

 used as a drug. The odor is pleasant, the taste sweet 

 and astringent. It colors the saliva red. 



Histology. — A cross-section of the root shows in general 

 a number of irregular transverse bands, alternately 

 light and porous and dark and dense. The former form 

 the groundwork in which the unconnected, sinuous, 

 diamond-shaped masses of shining sclerenchymatic wood 

 tissue are embedded. Fine medullary rays divide the 

 whole into equal sections. These are one to three cells 

 wide and contain a red brown pigment. The dense 

 masses are made of long, polygonal, thick- walled, finely 

 dotted wood cells, colored a deep red brown. The 

 porous ground tissue consists of polygonal slightly thick- 

 walled parenchyma through which run the large pitted 

 vessels, singly or in couples. They often occupy the 



