Am.  Jour.  Pharni. 
Jan.,  1892. 
African  Copaiba  " So-called! 
35 
portion  had  a  specific  gravity  of  0-992  at  150  C.  It  yielded  by  dis- 
tillation with  steam  40-2  per  cent,  of  a  pale  yellow  essential  oil, 
boiling  from  264-2700  C,  (uncorrected)  and  having  a  specific 
gravity  of  09188  at  150  C.  The  oil  was  readily  soluble  in  petro- 
leum ether  and  ether  (735),  less  soluble  in  pure  ether  (720),  and 
only  slightly  soluble  in  rectified  spirit  and  glacial  acetic  acid. 
The  crystals  were  purified  in  the  same  manner  as  those  from  (A) 
and  found  to  have  the  same  melting  point  (1240  C.),  and  to  be  dis- 
tinctly acid.  This  melting*  point  is  somewhat  close  to  that  of  a 
crystalline  resin  obtained  by  Fliickiger1  from  gurjun  balsam  (m.  p. 
126-1300  C),  but  that  body  was  indifferent,  whilst  this  from  the 
African  oleo-resin  is  markedly' acid,  distinctly  electrical  by  friction, 
and  appears  to  resemble  in  general  characters  the  oxycopaivic  acid 
(melting  point  about  1200  C.)  found  by  Fehling2  in  a  deposit  from 
a  Para  copaiba.  From  neither  of  the  oils — of  specimens  (A)  and 
,(B) — could  crystals  be  obtained  by  passing  dry  hydrochloric  acid 
gas  through  them,  either  at  normal  temperature  or  immersed  in  a 
freezing  mixture,  as  has  been  stated  to  be  the  case  by  Soubeiran  and 
Capitaine3  with  Maracaibo  oil  under  similar  treatment,  but  they 
gave  reddish-brown  fuming  liquids,  agreeing  with  the  behavior  of 
an  oil  distilled  from  Para  copaiba  by  those  authors. 
I  have  failed,  notwithstanding  several  attempts,  to  obtain  crystals 
of  a  hydrochloride  by  this  method,  when  operating  on  the  oil 
obtained  from  the  Maracaibo  variety,  and  in  this  respect,  therefore, 
my  experiments  confirm  those  of  Brix,4  and  show  that  the  forma- 
tion of  this  crystalline  body  from  pure  copaiba  oil  appears  somewhat 
uncertain. 
A  ready  test  proposed  by  Fliickiger,5  for  distinguishing  between 
copaiba  and  gurjun  balsams,  and  which  has  been  made  official  in 
the  United  States  Pharmacopoeia,  consists  in  adding  to  a  solution  of 
the  balsam  in  carbon  bisulphide  a  drop  of  nitric  and  sulphuric  acids 
previously  mixed  and  cooled,  when  in  the  case  of  gurjun  balsam  an 
intense  violet  color  is  produced. 
On  applying  this  test  to  samples  (A)  and  (B),  in  comparison  with 
1  Pharm.  Journ.  [3],  viii,  725. 
2  Ann.  Ch.  Pharm.;  xl,  no. 
8  Journ.  Pharm.,  xxvi,  70. 
4  Monatshefte,  [2],  p.  507. 
5  Pharm.  Journ.  [3],  vii,  p.  2. 
