442 BOTANY OF SOCOTRA. 





1. 



2. 



c 



7810 



77-85 



H 



10-61 



1061 







11-29 



11-54 



10000 10000 



" The portion insoluble in ether dissolves in water, and, when evaporated to dryness 

 forms a hard, brittle, transparent, brown- coloured film. The aqueous solution has an 

 acid reaction, and gives with lead acetate a white precipitate, which does not dissolve 

 on boiling. This portion is either identical with, or very closely allied to, gum- 

 arabic. 



" ' Ameero ' is therefore a gum-resin, and appears to be identical with the ' olibanum ' 

 derived from various species of Boswellia. Our analyses of the resinous portion agree 

 fairly well with those of Johnstone (Watt's Diet., art. ' Olibanum '), the discrepancy 

 being probably due to our not having, before burning, purified with sufficient care, 

 the quantity at our disposal being somewhat limited." 

 Page 55, line 8 from top. An account of the anatomy of this Balsamodendron is not given 

 here, for the same reasons as are stated under note to page 49. 



Professor Dobbie and Dr G. G. Henderson have been so kind as to analyse the gum- 

 resin, and they report — 



" ' Logahan ' occurs in small, brittle, colourless, or light brown-coloured drops or 

 tears, which have a slight terebinthinous smell and taste. It is insoluble in water, 

 soluble in ether, chloroform, benzene, and carbon bisulphide, and partially soluble in 

 petroleum-ether, and alcohol. By the action of the last solvent it can be split up into 

 two distinct resins. The percentage composition of ' logahan ' is approximately 



Portion insoluble in alcohol, . . . 320 



Portion soluble in alcohol, . . . 65 



Volatile oil soluble in ether, . . . 1*5 



Impurity insoluble in ether, . . . 15 



10000 



" The portion soluble in alcohol is a hard, brittle, yellow, transparent resin, with a 

 pleasant aromatic odour. It is insoluble in water and petroleum ether, but soluble in 

 ether, benzene, chloroform, and carbon bisulphide. Three analyses gave the following 

 results : — 





1. 



2. 



3. 



c 



76-44 



7514 



7730 



H 



1012 



991 



1014 



O 



1344 



14-95 



1256 



10000 10000 10000 



" The portion insoluble in alcohol is a white resin, which melts and boils at a low 

 temperature, solidifying on cooling to a hard, brittle, transparent mass, insoluble in 

 water, and soluble in ether, carbon, bisulphide, benzene, chloroform, and petroleum- 

 ether. Two combustions gave the following numbers : — 



