230 LEGUMINOS^. 



according to Engel/ it is produced by G. oficinalis, the Caniine of the 

 natives. 



The finest sort, called by the collectors white copaiba, is met with 

 in the province of Para, where Cross ^ saw a tree of a circumference of 

 more than 7 feet at 3 feet from the ground. Its trunk was clear of 

 branches to a height of at least 90 feet. The collector commenced the 

 work by hewing out with his axe a hole or chamber in the trunk about 

 a foot square, at a height of two feet from the ground. The base or 

 floor of the chamber should be carefully and neatly cut with a gentle 

 upward slope, and it should also decline to one side, so that the balsam 

 on issuing may run in a body until it reaches the outer edge. Below 

 the chamber a pointed piece of bark is cut and raised, which, enveloped 

 wdth a leaf, serves as a spout for conveying the balsam from the tree to 

 the tin.^ The balsam, continues Cross, came flowing in a moderate sized 

 cool current, full of air bubbles. At times the flow stopped for several 

 minutes, when a singular gurgling noise was heard, after which followed 

 a rush of balsam. When coming most abundantly a pint jug would 

 have been filled in the space of one minute. The whole of the wood cut 

 through by the axeman was bedewed with drops of balsam; the bark is 

 apparently devoid of it. Trees of the largest size in good condition will 

 sometimes yield four " potos," equal to 84 English imperial pints. 



Description — Copaiba is more or less viscid fluid, varying in tint 

 from a pale yellow to a light golden brown, of a peculiar aromatic, not 

 unpleasant odour, and a persistent, acrid, bitterish taste. Para copaiba 

 newly imported is sometimes nearly colourless and almost as fluid as 

 water.' The balsam is usually quite transparent, but there are varieties 

 which remain always opalescent. Its sp. gr. varies from 0'940 to 

 0*993, according as the drug contains a greater or less proportion of vola- 

 tile oil. Copaiba becomes more fluid by heat ; if heated in a test-tube 

 to 200° C. for some time, it does not lose its fluidity on cooling. It is 

 sometimes slightly fluorescent. It dissolves in several times its weight 

 of alcohol 0'830 sp. gr., and generally in all proportions in absolute 

 alcohol,^ acetone, or bisulphide of carbon, and is perfectly soluble in an 

 equal volume of benzol. Glacial acetic acid readily dissolves the resin 

 but not the essential oil. 



Copaiba that is rich in resin of an acid character, unites with the 

 oxides of baryum, calcium, or magnesium, to form a gradually hardening 

 mass, provided a small proportion of water is present. Thus 8 to 16 

 parts of balsam will combine as a stiflf compound when gentl}^ warmed 

 with 1 part of moistened magnesia ; and still more easily with lime or 

 baryta. 



Buignet has first shown (1861) that copaiba varies in its optical 

 power. A sample from Trinidad examined by one of us was strongly 



^ Zeitschrift der Oeselhchaft fiir Erdkunde garded by the dealers with suspicion, wc are 



2?t Berlin, v. (1870) 435. not of opinion that it was sophisticated. 



^ Report to the Under Secretary of State ' Such is the case with some very 



for India, on the investigation and collect- authentic specimens collected for one of us 



ing of plants and seeds of the india-rubber in Central America Ijy De Warszewicz, but 



trees of Para and Ceara, and Balsam of other samples which we had no reason to 



Copaiba. March 1877, — 8. supposeadulterated, left a certain amoimt of 



^ See figure in the above Report. white residue when treated with twice their 



* We saw such as this which had been loeight of alcohol sp. gr. 0'796. 

 imported into London in 1873 ; though re- 



