Am.  Jour.  Pharm,  ) 
April,  1879.  / 
Resin  and  Gum  of  Gamboge. 
It  is  soluble  in  alcohol,  ether,  chloroform,  bisulphide  of  carbon, 
solutions  of  ammonia  and  potassa,  and  partially  soluble  in  petroleum 
benzin.  To  form  the  salts  of  this  acid  the  experiments  of  Johnston 
and  Buchner  were  followed,  with  slight  modifications. 
The  resin  dissolves  very  readily  in  warm  ammonia  water,  forming  a 
•dark  red  solution  of  gambogiate  of  ammonium.  The  potassium  salt  is 
made  bv  dissolving  the  resin  in  solution  of  potassa,  the  solution  being 
also  dark  reddish-brown.  On  standing  for  some  time,  a  gelatinous 
deposit  is  formed  in  each  of  the  above  solutions.  The  ammonia 
doposit  was  exposed  until  dry;  the  residue  left  was  hard  and  brittle, 
insoluble  in  water,  soluble  in  alcohol  and  ether,  and  in  appearance 
resembles  the  resin. 
To  form  the  sodium  salt,  a  portion  of  the  ammonia  solution  was 
treated  with  a  solution  of  chloride  of  sodium,  when  a  yellow  precipi- 
tate was  thrown  down.  When  the  solutions  are  heated  before  mixing, 
the  precipitate  is  much  more  dense. 
Another  portion  of  the  ammonia  solution  was  treated  with  a  solution 
of  chloride  of  barium,  when  a  dark  brick-red  precipitate  of  gambogiate 
of  barium  was  thrown  down.  The  calcium  salt  is  formed  by  using  a 
solution  of  chloride  of  calcium  as  the  precipitant  ;  the  precipitate  is  of 
a  brownish-yellow  color.  Both  these  salts  are  soluble  in  alcohol  and 
ether ;  on  the  evaporation  of  the  solutions  the  salts  are  left  in  the  form 
of  a  fine  powder. 
The  lead  salt  was  made  in  a  like  manner  by  precipitating  with  solu- 
tions of  neutral  and  basic  acetate  of  lead  ;  with  the  former  the  precip- 
itate is  yellow,  while  with  the  latter  it  is  of  an  orange-yellow  color. 
These  are  also  soluble  in  alcohol  and  ether,  and  are  likewise  left  in  the 
form  of  fine  powder  on  evaporation  of  the  solution. 
When  to  an  alcoholic  solution  of  the  resin  an  alcoholic  solution  of 
nitrate  of  silver  is  added,  no  precipitate  is  formed  until  after  the  addi- 
tion of  a  small  amount  of  ammonia,  when  the  gambogiate  of  silver  is 
thrown  down  as  a  yellow  precipitate  ;  on  exposure  to  the  air  this  pre- 
cipitate changes  very  rapidly,  becoming  of  a  dark  blackish-green  color. 
The  gambogic  acid  also  forms  salts  with  copper,  iron,  strontium, 
etc.,  by  precipitating  its  solution  with  a  solution  of  a  salt  of  these 
metals. 
The  resin  was  boiled  with  strong  nitric  acid  until  red  fumes  ceased 
to  be  given  off",  and  the  solution  became  of  a  thick  syrupy  consistence 
