COPAIBA 493 



hard and brittle. The presence of fixed oil can also be detected by 

 the high ester value ; copaiba resin consists almost entirely of 

 resin-acids and has a very low ester value (seldom over 15 ; fixed 

 oils about 190). 



Volatile oils, such as turpentine, may often be detected by distilling 

 off the volatile oil in a current of steam and determining its specific 

 gravity (0-896 to 0'910), boiling-point (250 to 270), and optical 

 rotation ( 7 to 35) (sp. gr. of turpentine 0-850 to 0-880 ; b.pt. 

 155 to 165). The optical rotation is important; a dextrorotatory 

 oil would indicate the presence of African copaibas (compare also the 

 official tests for Oleum Copaibse). 



Colophony. Colophony may be added to thin copaibas without 

 making them suspiciously viscous. Copaiba should form a transparent 

 solution with one-third of its volume of solution of ammonia. 



Paraffin Oil. Five gm. of the copaiba boiled with 15 c.c. of 95 

 per cent, alcohol for one minute and cooled should not separate oily 

 drops (of paraffin oil). 



Gurjun balsam, an oleo-resin obtained by incision from the trunk 

 of Dipterocarpus turbinatus (N.O. Dipterocarpece) and other species, 

 large trees indigenous to eastern India and Burma, is used both 

 as a medicine and for various technical purposes. It somewhat 

 resembles copaiba hi odour and taste, but is usually darker in colour 

 and fluorescent. It contains from 40 to 80 per cent, of volatile oil 

 together with neutral and acid resins and has therefore a composi- 

 tion analogous to that of copaiba. Its presence in copaiba may be 

 recognised by adding 4 drops to a mixture of 5 c.c. of glacial acetic acid 

 and 4 drops of nitric acid ; a purple or reddish coloration indicates 

 gurjun balsam. It may also be detected by dissolving 2 drops of 

 the balsam in 20 drops of carbon disulphide and adding a drop of a 

 freshly prepared and cooled mixture of nitric and sulphuric acids ; 

 if gurjun balsam is present a violet coloration will be produced, 

 but it has been shown that a similar colour has been occasionally 

 yielded by genuine balsams. A similar test may be applied to the 

 volatile oil separated from the copaiba by steam distillation ; not 

 more than a faint violet colour should be produced. 



Sophistication by mixing a cheap thin copaiba with a more valuable 

 thick copaiba is difficult to detect. 



Uses. The active principles of copaiba are absorbed into the 

 blood, the volatile oil, at least, being excreted by the kidneys, bronchi, 

 and skin ; hence copaiba produces along the whole genito- urinary 

 tract, as well as in the bronchi, a stimulant and disinfectant action, 

 increasing the mucous secretion and exciting expectoration. It is 

 now chiefly employed in inflammatory affections of the bladder 

 and urethra, and occasionally in chronic bronchitis. The resin is 

 inert or nearly so. 



