230 



LEGUMINOS^. 



natives. 



^ 



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

 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 



The collector commenced the 



branches to a height of at least 90 feet. 



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 

 with 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 de.void 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 

 irom 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 

 ™<;h remain always opalescent. Its sp. gr. varies from 0-l}40 to 

 0-99 3 according as the drug contains a greater or less proportion of vola- 

 l % o ^<^Paiba becomes more fluid by heat ; if heated in a test-tube 

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

 sometimes slightly fluorescent. It dissolves in several times its weight 

 1 ^l,, ^'^'^^ ^P- S^-' 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 

 les of baryum, calcium, or magnesium, to forma gra 

 mass, provided a small proportion of water is present 



•^ i-iL — lesiii or an acia cnaracttJi, uiiii't>>j .-— - . 



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

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

 parts of balsam will combine as a stiff compound when gently warmea 

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

 baryta. . =■ ' 



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

 ^er. A sample from Trinidad examined by one of us was sivongiy 



power 



zu Berlin, v. (1870) 435. 



fnr iV^ ^"^ ^^'^ Under Secretary of State 

 IZ A T '^^ i^^^^tigation and collect 

 trfef o^f P ' ^"""^ T^^^ «f ^^^ india-rubber 



! See figure in the above Report. 



imrZZr^.^''T^ f *^^« ^l^i^h had been 

 imported into London in IR?-? . +i,^, ' i „ 



we are 



garded by the dealers with suspicion, « 

 not of opinion that it was sophisticatea 



«Snch is the case >^ith /^'"^'fS 

 authentic specimens collected tor o' 

 in Central America by Do W^rs2c« la- ^ ^^ 

 other samples which we had no re-^^ ^ 

 suppose adulterated, left a f r**}".^^?, (heir 

 white residue when treated with iu^^ce 



weiijlit of alcohol sp. gr. O'yOo- 



