87 



taken from the stem of the living plant. Both the recent, 

 and that which has been kept, possess the fragrance already 

 alluded to, and which adapts it so well for burning as a 

 frankincense. Its fracture is bright and conchoidal, and it is 

 remarkably brittle under the knife or file. 



Chemical Properties. — It is only partially soluble in 

 alcohol. Upon evaporating, the alcoholic solution — a yellow, 

 oily-looking substance — remains, giving off whilst hot a 

 vapour which has a peculiar aromatic odour. This sub- 

 stance, the residue insoluable in alcohol, appeared however, 

 to be a mixture of volatile oil and resin. The colour is 

 associated with the oil and resin. The insoluble residue 

 was treated by ether, which appeared to extract the same 

 sort of substance as had been extracted by alcohol — viz., 

 the oleo-resinous matter. The white powder not soluable 

 in alcohol or ether was not dissolved by boiling water, nor 

 by a mixture of equal parts of rectified spirit and water. 

 Iodine did not render it blue. When heated per se, it gave 

 off a vapour which had an aromatic odour : it finally fused, 

 burnt with fuliginous flame, and left a carbonaceous residue. 

 The white powder insoluble in alcohol and ether, became of a 

 deep brick red colour in cold nitric acid. When acted upon 

 by hot nitric acid red fumes were given off, and an orange 

 red-coloured residue was obtained by evaporating the acid. 

 This residue had no bitter taste, This residue, after being 

 exhausted by alcohol and ether, yielded to water no gummy 

 matter. A small quantity only having been acted upon by 

 nitric acid, no evidence of oxalic acid could be detected. 

 When boiled in a solution of caustic alkali little or none 

 appeared to be acted on ; in winch respect, therefore, it 

 differs from the gum-resins. The essential oil of turpen- 

 tine scarcely acts upon it. 



From the foregoing chemical experiments, it may be 

 concluded that the substance in question cannot be classed 

 among the gum-resins, as shown by its indifference to certain 



