1888-89.] Wood of certain Resin-Producing Trees. 383 



Naphtha Resin. — The solution on cooling shows whitish 

 flocculent matter separating, proving that at least a portion 

 of it is not very soluble in cold naphtha, and therefore 

 different from ordinary pine resin. It is brittle, semitrans- 

 parent, and pale yellow in colour. In cold alcohol this resin 

 is insoluble, but when the spirit is heated the resin turns 

 opaque,, and swells without wholly dissolving. Nitric and 

 sulphuric acids give with it no reactions. 



The alcohol resin of Sal is darkish brown in colour and 

 brittle. It is — 



1. Insoluble in bisulphide of carbon. 



2. Do. in spirits of turpentine. 



3. Do. in benzole. 



4. Do. in chloroform. 



5. Do. in olive oil. 



6. Very soluble in acetone. 



This resin has no marked reaction with sulphuric acid. 

 In nitric acid it dissolves, and turns dark brown. 



The ether resin is light brown and brittle. It crives no 

 reaction with sulphuric, but with nitric acid it turns dark 

 brown. The quantity of it obtained was too small to test 

 its solubilities. 



Lignum vit.-e. — The Giiaiacum officinale which yields this 

 wood is k slow-growing evergreen tree, native of Jamaica, 

 Cuba, and other West Indian Islands, and also of some of 

 the northern parts of the South American continent. The 

 older accounts of this tree state that it attains a great size. 

 On the other hand, Bentley and Trimen, in their recent 

 work on Medicinal Plants, give its height at from 20 to 30 

 feet ; while Laslett, an excellent authority, says that it is 

 from 30 to 40 feet high. Can it be, that, owing to Lignum 

 vitce being much in demand, the trees are now cut down at 

 a younger age than formerly ? 



The heart-wood of Cfuaiacum is of a brownish colour, 

 changing apparently to a peculiar greenish-brown, after a 

 fresh cut surface has been exposed a short time to the air. 

 As is the case with many other woods, the colour is due to 

 the resin which it contains. The sap wood, though durable, 

 is said to contain little or no resin, but I am not aware 

 whether this has been determined by experiment. The 



TRANS. BOT. SOC. VOL. XVII. 2 D 



