^°'Dec"'"i8^82'''''"'}        Examination  of  Balsam  of  Peru.  611 
Castor  oil  passes  so  completely  into  the  upper  ethereal  layer  that 
the  ammoniacal  layer,  upon  being  aeidified,  s.-arcely  separates  a  single 
oil  globule. 
In  the  case  of  colophony  solution  and  copaiba  balsam  the  resin  com- 
bines with  the  ammonia,  so  that  when  the  lower  layer  is  rendered  acid 
and  boiled,  a  considerable  separation  of  solid  resin  takes  place. 
With  purified  storax  there  is  scarcely  any  separation  into  two  layers, 
but  it  yields  a  stiff  homogeneous  jelly  that  will  hardly  flow  from  the 
glass. 
This  holds  nearly  good  for  a  mixture  of  equal  quantities  of  Peru 
balsam  and  purified  storax ;  if  less  storax  be  present  there  is  a  separa- 
tion into  layers,  but  gelatinous  lumps  are  to  be  seen  smimming  in  the 
ethereal  solution.  Whilst  also  with  Peru  balsam  the  lower  ammoni- 
acal layer,  when  separated  and  supersaturated  with  acetic  acid,  appears 
only  slightly  turbid  upon  boiling,  the  lower  liquid  layer  from  a  balsam 
adulterated  with  copaiba  balsam  or  colophony,  when  similarly  treated, 
shows  a  separation  of  more  or  less  solid  resin. 
D.  Action  of  Strong  Sulphui^ic  Acid  on  Balsam  of  Peru. — If  Peru 
balsam  be  mixed  with  at  least  an  equal  quantity  of  concentrated  sul- 
phuric acid,  the  mass  becomes  hot,  blackened  and  thickened.  Upon 
washing  it  with  hot,  and  afterwards  with  cold  water,  it  is  at  first  plas- 
tic, but  after  cooling  becomes  solid  and  brittle.  If  it  be  spread  out 
smooth,  dried  superficially  with  blotting  paper,  crushed  and  placed  in 
a  test  tube  with  several  times  its  quantity  of  ether,  complete  solution 
takes  place  in  a  short  time.  When  a  small  quantity  (1  to  2  grams)  of 
Peru  balsam  is  used  no  smell  or  frothing  or  evolution  of  vapor  is 
observed  when  the  mixing  takes  place ;  but  with  larger  quantities 
these  phenomena  are  manifested,  sulphurous  acid  being  set  free.  When 
the  test  is  used  with  the  adulterants  mentioned,  their  behavior  in  small 
quantities — 1  gram — exactly  resembles  that  of  genuine  Peru  balsam  ; 
except  in  the  case  of  copaiba  balsam,  with  which,  even  in  the  smallest 
quantity,  there  is  strong  frothing  and  an  evolution  of  white  vapor  and 
sulphurous  acid.  With  colophony,  benzoin,  storax  and  castor  oil, 
these  appearances  are  first  manifested  with  a  quantity  exceeding  two 
grams.  Consequently,  if  frothing  and  evolution  of  sulphurous  acid 
commences  when  the  quantity  is  limited  to  1  gram,  the  presence  of 
copaiba  l^alsam  may  l)e  concluded. 
The  washed  resinous  mass  is  completely  soluble  in  ether,  as  before 
mentioned,  so  long  as  it  contains  neither  benzoin  nor  storax.    But  if 
