Resin  and  Gum  of  Gamboge. 
{Am.  Jour  Phann. 
April,  1879. 
rated,  leaving  a  white  crystalline  residue  corresponding  to  the  supposed 
porphyroxin  of  the  former  experiment,  and  was  probably  carried  down 
with  the  resin. 
The  filtrate  (?)  contained  a  small  quantity  of  the  supposed  alkaloid, 
which  was  precipitated  by  Mayer's  test.  The  filtrate  was  found  to  be 
free  from  tartaric  acid,  but  to  contain  both  citric  and  malic  acids.  A 
portion  of  the  powder,  previously  exhausted  with  water,  acidulated  with 
acetic  acid,  was  then  percolated  with  alcohol,  a  deep  red  tincture  being 
obtained.  This  produced  a  bright  red  precipitate  with  solution  of 
protochloride  of  tin.  A  portion  evaporated  to  dryness  and  treated  with 
water  gave  a  red  solution,  precipitated  by  ammonia  and  Mayer's  test, 
the  precipitate  being  sanguinarina.  The  residue  was  a  reddish-brown 
resin,  soluble  in  chloroform  and  ether,  giving  no  characteristic  reaction 
with  the  mineral  acids. 
THE  RESIN  AND  GUM  OF  GAMBOGE. 
By  David  Costelo,  Ph.G. 
{From  a  thesis  presented  to  the  Philadelphia  College  of  Pharmacy.) 
Gamboge  consists  of  resin  and  giim,  in  variable  proportions.  The 
amount  of  resin  represents  its  value  both  medicinally  and  as  a  pigment. 
Thinking  it  would  be  of  interest  to  ascertain  the  value  of  the  present 
commercial  varieties,  specimens  of  pipe,  lump  and  powdered  gamboge 
were  procured. 
Ten  grams  of  each  were  treated  with  alcohol  until  the  color  was 
entirely  removed.  The  gum,  which  is  insoluble  in  alcohol,  was  dis- 
solved in  cold  water  and  the  solution  filtered,  to  remove  insoluble 
matter.    The  results  are  given  in  the  following  : 
In  10  grams  of         Resin.  Gum.  Impurities.  Total. 
Lump,  6  76  grams.  2  74  grams.  -38  gram.  9*88  grams. 
Pipe,  7-93  1-945  '015  9-89 
Powder,  7*66  2*25  -07  998 
As  there  is  a  small  quantity  of  water  contained  in  gamboge,  the  dis- 
crepancy, in  the  above  total,  is  attributed  to  this  cause. 
The  resin  was  found  to  be  of  a  bright  reddish-brown  color,  translu- 
cent, very  brittle,  and  easily  rubbed  into  a  bright  yellow  powder.  This 
is  the  so-called  gambogic  acid,  C20H23O4.  Its  solution  in  alcohol  or 
ether  has  an  acid  reaction  to  test  paper,  and  it  unites  with  bases  to  form 
salts. 
