on Guaiacum. 
93 
by the alkalis. If heat be employed in forming this solution, 
the resin is speedily decomposed ; and if the whole of the 
acid be evaporated, there remains a black coaly substance, 
together with some sulphate of lime. 
6 . Nitric acid appears to exert a more powerful action on 
guaiacum than on any of the resinous bodies. 
100 grains of pure guaiacum previously reduced to powder, 
were cautiously added to two ounces of nitric acid, of the 
specific gravity of 1.39. The resin at first assumed a dark 
green colour, a violent effervescence was produced, attended 
with the emission of much nitrous gas, and the whole was 
dissolved without the assistance of heat, which is not the case 
with the resins in general, for when these bodies are thus 
treated with nitric acid, they are commonly converted into an 
orange-coloured porous mass. 
The solution thus formed, yielded while recent, a brown 
precipitate with the alkalis, which was redissolved on the 
application of heat, forming; a deep brown liquid. 
Muriatic acid also separated the guaiacum from this solu- 
tion, not however without having undergone some change. 
Sulphuric acid caused no precipitate. 
After this solution of guaiacum in nitric acid had remained 
undisturbed for some hours, a considerable proportion of 
crystallised oxalic acid was deposited. 
When guaiacum was treated with dilute nitric acid, the 
results were somewhat different. A slight effervescence took 
place, and part of the resin was dissolved, the remainder 
being converted into a brown substance, resembling the pre- 
cipitate obtained from the alcoholic solution as above men- 
tioned. (2. E.) 
