232 
Adulteration  of  Castor  and  Olive  Oils.  { 
Am.  Jour.  Pharm. 
May,  1893. 
mixed  with  an  equal  weight  of  sulphuric  acid — that  is,  2  volumes 
of  oil  to  I  of  sulphuric  acid  (97  per  cent.) — our  figures  do  not  agree 
with  those  recorded  by  other  observers.  Alien  gives  65 0  C,  Arch- 
butt  gives  460  C,  and  we  have  repeatedly  found  720  to  74°  for 
castor  oil  of  undoubted  purity. 
Taei,k  I. 
I, 
2, 
3, 
4, 
5, 
6, 
7, 
S, 
Specific 
Gravity. 
Saponification  Iodine 
Equivalent.  Absorption. 
Temperature 
Rise. 
•9735 
400 
•9721 
420 
•9723 
400 
•9740 
445 
■9766 
428 
•9752 
403 
•9739 
440 
•9719 
440 
67 
65 
64 
6oc 
62c 
63c 
6oc 
62c 
6ic 
6oc 
62c 
The  usual  adulterants  of  castor  oil  are  poppy  seed,  cocoanut,  lard, 
rosin  and  blown  oils.  The  figures  above  quoted  practically  exclude 
all  but  rosin  and  blown  oils.  Moreover,  in  every  case  the  samples 
were  freely  soluble  in  glacial  acetic  acid,  which  is  a  further  indica- 
tion of  the  absence  of  other  oils.  Since  the  gravity  of  blown  oil 
seldom  rises  above  -970,  and  its  saponification  equivalent  seldom 
exceeds  284,  we  were  confident  that  rosin  oil  was  the  adulterant 
used.  The  high  gravity  and  saponification  equivalent  were  con- 
firmatory of  this,  as  was  the  low  iodine  absorption.  And  if  our 
observations  on  pure  castor  oil  were  correct,  as  we  certainly  believe 
them  to  be,  in  the  case  of  the  rise  in  temperature,  the  observed  rise 
in  the  case  of  the  impure  samples  pointed  to  the  presence  of  hydro- 
carbons. To  absolutely  confirm  our  suspicions  we  used  three  further 
tests  of  extreme  simplicity,  but  of  great  utility.  A  drop  of  the  oil 
was  placed  on  the  back  of  the  tongue,  and  in  a  minute  nothing  but 
the  disagreeable  taste  of  rosin  oil  could  be  detected.  The  samples 
did  not  appear  fluorescent  in  bulk,  but  when  mixed  with  an  equal 
volume  of  ether  and  examined  in  tubes  they  were  distinctly  fluores- 
cent. This  is  the  usual  method  of  observing  the  fluorescence  of  oils, 
but  in  the  case  of  viscous  oils,  like-castor,  we  have  found  the  fluores- 
cence much  more  intense  when  the  sample  without  admixture  with 
ether  is  allowed  to  run  down  the  side  of  a  thin  glass  tube  and  the 
