238 
NEW  VARIETy  OF  BALSAM  OF  COPAIBA. 
Essential  oil       .       .       65  per  cent. 
Resin        .        .       .       34  « 
Acetic  acid  and  water  1  " 
100 
I  find  that  the  essential  oil  in  its  various  reactions  with  potas- 
sium, iodine,  nitric  acid,  &c,  and  moreover  in  taste,  exactly  cor- 
responds with  those  presented  by  pure  essence  of  copaiba.  The 
resin  left  by  distillation  of  the  balsam,  either  with  or  without 
water,  is,  if  deprived  of  the  whole  of  the  essential  oil,  extremely 
hard.  Its  entire  solubility  in  coal  naphtha  proves  the  absence -of 
any  of  the  soft  resin  which  exists  in  most  of  the  copaiba  of  com- 
merce. This  hard  resin  (copaivic  acid)  being  most  probably  the 
active  principle  of  balsam  of  copaiva,  I  am  induced  to  think  its 
quantity  and  purity  in  the  one  I  have  examined  is  indicative  of 
its  superior  value  as  a  medicament.  The  dark  color  of  the  bal- 
sam may  perhaps  limit  its  employment,  but  the  large  quantity  of 
copaivic  acid  it  contains  renders  it  valuable,  as  the  latter  may  be 
made  available  by  heating  the  filtered  balsam  to  the  boiling  point 
with  a  small  quantity  of  caustic  potash  or  soda  lye,  of  sp.  g%. 
1.34,  and  separating  the  resinate  of  potash  or  soda  from  the  es- 
sential oil.  The  alkaline  resinate  may  then  be  dissolved  in  wa- 
ter, giving  a  colorless  solution  (similar  to  Frank's  specific),  or 
the  balsam  may  be  treated  with  magnesia  to  form  the  ordinary 
copaiba  pill. 
I  have  in  conclusion  remarked  : — 
1st,  That  the  essential  oil  obtained  by  the  distillation  of  bal- 
sam copaiba  has,  like  several  other  hydrocarbons,  the  property 
of  dissolving  indigo. 
2dly,  The  new  variety  of  balsam  above  described  presents  the 
curious  property  of  becoming  gelatinous  (so  much  so  that  the 
tube  may  safely  be  inverted),  if  heated  to  230°  Fah.,  even  if  a 
sealed  tube  be  employed.  This  character  being  dissimilar  to  the 
one  given  in  the  same  circumstances  with  such  other  balsams  as 
I  had  at  my  disposal,  I  am  induced  to  attribute  it  to  the  large 
amount  of  "  hard  resin  "  it  contains. 
3dly,  Balsams  of  copaiba  in  general  give,  on  distillation  with 
two  per  cent,  sulphuric  acid,  a  beautiful  blue  volatile  oil.  Chlo- 
rine, hypochlorite  of  lime,  and  bichromate  of  potash,  give  a  si- 
