3Q0 EXPERIMENTS ON GUAIACUM. 



been paid to the subject, since many of the alterations which 



it undergoes when treated with different solvents, have been 



mentioned by various authoi-s. 



External and Sect. I. — Guajacmn has a green hue externally ; is in 



.obvious charac- , , . 



tersofguaia- some degree transparent ; and breads' with a vitreous fracture, 



•^""^ When pulverised it is of a gray colour, but gradually be- 



comes greenish on exposure to air. 



It melts when heated, and diffuses at the same time a pun- 

 gent aromatic odour. 



It has when in powder a pleasant balsamic smell, but 

 scarcely any taste, although when swallowed it excites a very 

 powerful burning sensation in the throat. 



Its specific gravity is 1.2289. 

 AqaeoussoTu- Sect. II. 1. — When pulverised guaiaoim is digested in a 

 moderate heat with distilled water, an opaque solution i^ 

 formed, which becomes clear on passing the whole through 2 

 filter. 



The filtrated liquor is of a greenish-brown colour] it has a 

 peculiar smell, and a sweetish taste. 



It leaves on evaporation a brown substance, which is soluble 

 in alcohol, nearly soluble in boiling water, and very little acted 

 \ipon by sulphuric ether. 



This solution was examined by the following reagents. 

 Filtered soluti- Muriate of alumina occasioned a brown insoluble prccipi- 



by rea^nts? ^^^^^ ^^^^'^ ^^^^^ ^^^"'"^ ^'^'^ elapsed. 



Muriate of tin formed a brown flaky precipitate under the 

 same circumstances. 



Nitiate of silver gave a copious brown precipitate. 



Suspecting the presence of lime in the solution, I added a 

 few drops of oxalate of ammonia, when the liquid immediately 

 became trubid, and deposited brown flakes, which, after having 

 been treated with boiling alcohol, yielded traces of oxalate of 

 lime. 



These effects, therefore, indicate the presence of a substance 

 in guaiacum, which possesses the properties of extract ;* the 



* By the terms extract, I mean that substance, which by 

 cliemists is called the extractive principle of vegetables. Vide 

 Thompson's Syst. of Chemistry, 2d edit, vol, iv. p. 276. 



action • 1 



