Am,A°n"-i£Sarm-}  Castor  Oil  Adulteration.  41 
The  petroleum  ether  used  had  a  specific  gravity  of  '7033  at 
60°  F. 
Twenty  cc.  each  of  castor  oil  and  petroleum  ether  were  mixed 
by  brisk  agitation  in  a  tall  graduated  tube  and  maintained  at  a 
temperature  of  60°  F. 
The  mixture  never  became  clear,  and  on  standing  for  about  an 
hour,  a  layer  of  petroleum  ether  collected  on  the  surface  measuring 
3  cc.  This,  as  we  shall  shortly  see,  has  a  very  important  bearing, 
and  it  should  be  borne  in  mind  that  the  same  experiment  was  tried 
on  many  samples  from  various  sources,  and  that  never  in  any  in- 
stance at  a  temperature  of  60°  F.  did  a  clear  mixture  result,  and 
in  all  cases,  a  separation  of  petroleum  ether  took  place  on  standing, 
amounting  to  practically  the  same  volume.  If  on  the  other  hand  the 
mixture  be  made  at  a  temperature  of  70°  F.  the  whole  of  the  ether 
is  dissolved,  or  if  the  mixture  made  at  60°  F.  be  shaken  and 
raised  to  70°  F.  perfect  solution  takes  place,  but  on  cooling  again 
to  60°  F.  the  same  amount  of  separation  occurs. 
Thus  far  we  have  seen  the  behavior  of  petroleum  ether  with  genu- 
ine castor  oil,  and  we  shall  now  see  how  it  behaves  with  adulterated 
samples.  For  this  purpose  samples  were  made  each  containing  5  per 
cent,  of  one  fixed  oil,  such  as  cotton-seed,  cocoanut,  etc. 
These  samples  in  all  cases  made  a  perfectly  clear  solution  with  an 
equal  volume  of  petroleum  ether  at  60°  F.,  and  in  no  instance  did  any 
separation  take  place  on  standing. 
We  thus  see  that  so  small  an  amount  as  5  per  cent,  of  a  fixed  oil, 
other  than  castor  oil,  when  present  is  sufficient  to  cause  the  whole  of 
the  petroleum  ether  to  combine  and  form  a  perfectly  clear  solution, 
and  I  think  that  it  has  clearly  been  shown  that  the  test  is  a  reliable 
and  a  safe  one. 
So  far  I  have  only  made  use  of  this  as  a  qualitative  test,  but  I  have 
hopes  that  by  adopting  certain  precautions  it  can  be  made  a  quantita- 
tive one,  for  I  find  that  if  two  volumes  of  petroleum  ether,  be  used  in- 
stead of  one,  and  thoroughly  mixed  by  agitation  at  a  temperature  of 
60°  F.,  separation  takes  place  in  the  adulterated  as  well  as  in  the  pure 
samples,  and  that  the  volume  of  the  ethereal  layer  increases  with  the 
amount  of  adulterant  present  with  a  corresponding  diminution  in 
the  lower  castor  oil  layer. 
To  demonstrate  this  I  have  here  three  tall,  graduated  tubes  of  60 
cc.  capacity. 
