1 80  Detection  of  Castor  Oil  in  Copaiba.     { AmxJPX Iz%!m' 
Etherial  extract.    Insoluble  por- 
Ten  grams  Soluble  in  strong       Alcoh.  extract       Sol.  in       Insol  in    tion  dissolved  in 
Comp.  extr.  colocynth,  strong  alcohol.         sol,  in  ether.       benzin.      benzin.    KHO,  then  aci- 
dulated by  HC1. 
Remains 
dis.  Precip. 
Theoretical  Yield,  7*78  2-00  -17        1-83        1*32  -51 
Own  make,  7*11  4-12  '90       3*00       2*55  -45 
Manufacturer,  770  4*35  roo       3*25        2*13  I'ii 
On  comparing  the  results  in  the  last  table,  it  will  be  seen  that  they 
do  not  exactly  correspond.  The  amounts  soluble  in  stronger  alcohol 
are  nearly  alike.  The  ether,  on  the  contrary,  dissolved  twice  as  much 
when  the  ingredients  were  all  mixed  together  as  when  they  were 
treated  separately.  In  order  to  verify  this  by  direct  experiment,  I  took 
one  gram  of  the  compound  extract  of  colocynth,  also  one  gram  of 
£ach  of  its  ingredients,  put  them  separately  into  six  two-ounce  vials, 
and  treated  them  respectively  with  one  and  a  half  fluidounces  of  ether, 
shaking  them  occasionally  for  two  days.  The  ether  was  next  poured 
off*  and  evaporated,  and  by  weighing,  it  was  found  that  the  soluble  por- 
tion of  the  compound  extract  of  colocynth  weighed  a  little  more  than 
twice  as  much  as  the  sum  of  the  soluble  parts  of  the  ingredients, 
treated  separately,  calculated  in  the  same  proportion  as  they  exist  in 
the  compound  extract.  The  petroleum  benzin,  as  well  as  the  solution 
of  potassa,  dissolved  more  of  the  compound  extract  of  colocynth  than 
they  did  of  its  component  parts,  when  treated  with  them  separately  ; 
while  the  dilute  muriatic  acid  did  not  throw  down  as  much  precipitate 
as  was  calculated,  from  the  amount  of  scammony  resin,  which  was 
expected  to  be  the  only  principle  remaining  in  solution.  It  will  be 
seen  from  the  above,  that  there  is  something  else  in  this  extract,  besides 
the  resin  of  scammony,  that  is  soluble  in  solution  of  potassa,  and  not 
precipitated  by  dilute  muriatic  acid.  It  may  be  that  the  soap,  or  some 
of  the  other  ingredients,  act  as  solvents. 
I  tried  to  separate,  from  the  compound  extract,  the  aloes,  soap  and 
part  of  the  extract  of  colocynth,  by  treating  it  with  water  ;  as  the  two 
first  are  almost  entirely  soluble,  and  the  latter  partially  so,  in  that  men- 
struum. By  experiments  it  was  found  that  nearly  all  of  the  compound 
extract  of  colocynth  was  dissolved,  which  was  undoubtedly  due  to  the 
solvent  action  of  the  soap. 
A  METHOD  of  DETECTING  and  ESTIMATING  CASTOR 
and  OTHER  FIXED  OILS  in  BALSAM  COPAIBA.1 
By  Dr.  Muter. 
This  oleo-resin,  commonly  but  wrongly  termed  a  balsam,  has  been 
said,  in  books,  for  many  years  back,  to  be  subject  to  admixture  with 
1  Read  before  the  Society  of  Public  Analysts,  November  15th,  1876.  From 
**'  The  Analyst,"  November  30,  1876. 
