Am.  Jour.  Pharm. 
May,  1893. 
}  Adulteration  of  Castor  and  Olive  Oils. 
235 
We  applied  still  another  valuable  test — that  of  the  melting-point 
of  the  fatty  acids,  obtained  after  saponifying  a  quantity  of  the  oil  with 
alcoholic  potash,  breaking  up  the  soap  with  sulphuric  acid,  and 
washing  free  from  the  latter  with  distilled  water.  The  fatty  acids 
of  pure  olive  oil  obtained  in  this  manner  we  found  almost  liquid  at 
230  C.j  whilst  many  of  the  oils  before  mentioned  melted  at  as  high 
Our  melting-point  figures  for  the  oils  submitted  for  analysis  were 
very  much  higher  than  those  of  pure  olive,  whilst  they  were  slightly 
lower  than  those  of  cotton-seed  oil.  Our  general  figures  are  embo- 
died in  Table  II. 
On  examining  these  figures,  we  found  that  the  specific  gravity, 
combined  with  the  saponification  equivalent,  showed  the  absence  of 
a  hydrocarbon  oil.  The  difficulty  was  now  to  identify,  if  possible,  the 
foreign  vegetable  or  fat  oil  present.  Except  the  saponification 
figures,  no  others  agreed  with  those  found  by  us  of  oils  of  known 
purity.  Arachis  oil  of  the  poorer  quality  could  have  been  used,  the 
specific  gravity  of  the  poorer  class  being  -920 ;  but  we  examined 
for  this  oil  by  Renard's  test,  and  were  able  to  say  that  it  was  not 
present.  In  the  same  manner  sesame  oil,  on  account  of  its  gravity 
and  other  general  figures,  might  have  been  the  adulterant,  but,  care- 
fully using  the  color-tests,  we  were  able  to  dismiss  it  from  our 
minds.  We  next  turned  our  attention  to  cotton-seed  oil,  this  oil 
being  one  used  very  largely  for  the  purpose  of  adulterating  olive  oil, 
on  account  of  its  pleasant  taste  and  general  adaptability  for  eating 
and  culinary  purposes.  We  found  that  the  high  melting-points  of 
the  fatty  acids  of  the  samples  submitted  to  us  agreed  well  with  that 
of  cotton-seed  oil,  whilst  the  general  color-tests  and  elaidin  tests 
also  confirmed  our  suspicions. 
To  further  strengthen  our  opinion  that  cotton-seed  was  the  adul- 
terant, we  carefully  prepared  the  fatty  acids  of  the  suspected  oils  and 
dissolved  them  in  alcohol,  and  then,  after  the  addition  of  nitrate  of 
silver,  heated  some  to  the  temperature  of  boiling  water.  After  some 
little  time  the  silver  was  much  reduced,  and  much  blackening^ was 
observed.  It  may  also  be  remarked  that,  on  heating  the  fatty  acid 
obtained  after  saponification  for  some  time  at  the  temperature  of 
boiling  water,  the  characteristic  odor  of  cotton-seed  oil  was  noticed, 
so  that,  by  a  review  of  these  results,  we  were  enabled  to  return 
every  one  of  these  samples  as  adulterated  with  cotton-seed  oil. — 
The  Chemist  and  Druggist,  April  8,  1893,  p.  488. 
as  35 
5°C. 
