616 
Exomination  of  Balsam  of  Peru. 
f  Am.  Jour.  Pharm.. 
\      Dec,  1882. 
with  0*30  gram  of  caustic  liniCj  without  the  addition  of  water,  and 
then  exhausted  with  petroleum  spirit,  which  dissolves  the  cinnamein 
(41  per  cent.)  of  the  balsam  together  with  all  the  castor  oil.  A  second 
quantity,  with  the  addition  of  water,  is  macerated  in  a  water  bath  for 
several  hours,  by  which  the  saponification  of  the  oil,  but  not  of  the 
balsam  is  induced.  Petroleum  spirit  then  dissolves  only  the  cinna- 
mein of  the  balsam.  The  difference  in  the  two  results  gives  the 
amount  of  castor  oil,  whilst  the  quantity  of  Peru  balsam  can  be  easily 
calculated  from  the  cinnamein.  Of  course  the  exactitude  of  the  result 
is  dependent  upon  the  complete  saponification  of  the  oil. 
6.  A  more  simple  plan  is  to  exhaust  the  sample  by  three  or  four 
shakings  with  petroleum  spirit,  and  then  to  estimate  the  soluble  con- 
stituents by  evaporating  the  solution,  and  the  insoluble  by  drying  the 
residue.  The  former  include  nearly  one-half  of  the  Peru  balsam,, 
together  with  castor  oil;  the  latter  more  than  one-half  of  the  Peru  bal- 
sam present.  By  subtracting  the  amount  undissolved  from  that  dis- 
solved, an  approximation  to  the  quantity  of  castor  oil  is  obtained. 
Example. — 1  gram  of  balsam  containing  23  per  cent,  of  added  cas- 
tor oil,  left  after  four  shakings  with  petroleum  spirit  0'40  gram  undis- 
solved, which  indicated  approximately  80  per  cent,  of  Peru  balsam. 
The  petroleum  spirit  left  upon  evaporation  0'60  gram  of  oily  residue,, 
which  quantity  indicated  somewhat  more  than  20  per  cent,  of  castor 
oil  (0-60— 0-40=0-20). 
(5).  Estimation  of  Admixture  of  Copaiba  Balsam. — a.  The  propor- 
tion of  Peru  balsam  is  estimated  directly  by  digesting  the  sample  for 
several  hours  with  caustic  lime  and  water,  exhausting  the  mass  com- 
pletely with  petroleum  spirit  and  leaving  the  filtered  liquid  to  evapo- 
rate. In  this  way  there  is  at  first  obtained  41  per  cent,  of  the  Peru 
balsam,  together  with  the  essential  oil  of  copaiba.  To  volatilize  the 
latter  the  residue  is  heated  in  a  water  bath  until  it  no  longer  percepti- 
bly loses  weight.  What  is  now  left  represents  41  per  cent,  of  Peru 
balsam,  whilst  the  loss  in  weight  gives  the  amount  of  essential  oil  of 
copaiba. 
b.  The  amount  of  copaiba  resin  is  found  by  means  of  the  caustic 
ammonia  test,  as  described  for  colophony.  If  to  this  be  added  the 
amount  of  essential  oil  as  obtained  in  the  preceding  experiment,  the 
total  will  represent  the  amount  of  copaiba  balsam  present. 
Example. — 1  gram  of  Peru  balsam  containing  30  per  cent,  of  added 
copaiba  balsam  after  being  digested  with  lime  and  water  gave  up  to> 
