372 
Powdered  Gamboge. 
Am.  Jour.  Pharm. 
July,  1896. 
per  cent,  and  less — of  starch,  a  quantity  too  small  to  be  classed  as 
an  adulteration,  and  yet  too  large  to  be  justified  by  the  Pharmaco- 
poeia. This  authority  recognizes  and  describes  only  pipe  gamboge, 
but  by  far  the  larger  number  of  druggists  buy  and  use  the  powder. 
So  it  happens  that  the  officially  described  article  is  not  the  one  in 
general  use. 
How  this  trace  of  starch  finds  its  way  into  the  drug  we  have  not 
been  able  to  determine.  A  well-known  firm  of  New  York  drug 
millers  being  asked  about  the  matter  replied  that  their  gamboge 
was  powdered  from  block  or  mass  and  broken  pipes,  upon  their  own 
premises,  under  their  own  supervision,  and  was  strictly  pure.  The 
only  explanation  they  could  offer  for  the  presence  of  starch  was 
that  block  or  mass  gamboge  was  moulded  in  forms  made  from,  or 
lined  with,  rice  straw,  of  which  a  very  little  becomes  mixed  with 
the  gum,  and  certain  qualities  are  occasionally  mentioned  in  London 
market  reports  as  blocky,  broken  and  ricey.  They  state,  however, 
that  they  have  never  observed  the  latter  in  the  American  market. 
Another  possible  explanation  is  that  the  mills  used  in  grinding 
contained  remnants  of  some  starchy  drug,  and  were  not  thoroughly 
cleaned  before  being  used  upon  gamboge.  However  this  may  be, 
it  is  certain  that  a  trace  of  starch  should  not  condemn  a  drug  other- 
wise pure,  and  if  a  starch-test  is  applied,  it  should  be  of  such  a  nature 
as  to  distinguish  between  small  and  excessive  amounts.  Far  better 
it  would  be  to  require  the  presence  of  from  75  to  80  per  cent,  of 
resin,  as  this  is  the  active  and  valuable  portion. 
In  order  to  ascertain  approximately  how  much  starch  powdered 
gamboge  contains,  a  convenient  quantity  was  exhausted  with  ether, 
the  small  amount  of  residue  dissolved  in  hot  water  and  cooled, 
when,  upon  adding  a  drop  of  iodine  solution,  a  faint  blue  color 
developed,  showing  the  presence  of  only  traces  of  starch.  This 
same  sample  gave  a  distinct  green  color  under  the  conditions  of  the 
official  test. 
Gamboge  resin  (cambogic  acid)  dissolves  completely  in  solutions 
of  the  caustic  alkalies,  and  is  precipitated  apparently  unchanged  upon 
the  addition  of  excess  of  acid.  Starch  also  dissolves  in  solution  of 
caustic  alkali.  Such  solution,  when  acidulated  with  hydrochloric  acid, 
shows  cloudiness,  but  no  perceptible  precipitate.  If  this  acidulated 
liquid  is  filtered  through  paper,  the  filtered  liquid  gives  no  reaction 
for  starch,  but  if  simply  strained  through  absorbent  cotton,  the 
