438 
Olive  Oil  and  its  Adulterations. 
Am.  Jour.  Pharru. 
Sept.,  1887. 
the  same  way.  The  addition  of  another  oil  to  olive  oil  renders  it  far 
less  agreeable  to  the  palate,  and  by  increasing  its  tendency  to  become 
rancid  makes  it  more  likely  to  offend  and  derange  the  stomachs  of 
those  who  consume  it.  When  pure  and  fresh,  olive  oil  is  most  whole- 
some as  an  article  of  food  and  as  a  condiment.  In  addition  to  the 
specific  gravity  the  following  tests  will  aid  in  determining  its  purity. 
1 .  Olive  oil  loses  its  transparency  and  begins  to  solidify  at  32°-36° 
F.,  and  is  completely  solidified  when  a  small  quantity  is  surrounded 
by  ice  or  a  freezing  mixture ;  but  when  mixed  with  poppy  oil  it  re- 
mains partly  liquid,  even  when  the  latter  forms  only  one-fourth  of  the 
mass.  If  more  than  one-third  poppy  oil  is  present,  it  does  not  solidify 
at  all,  unless  cooled  much  below  32°  F. 
2.  The  elaidin  test  is  a  very  useful  one  in  the  examination  of  olive 
oil.    There  are  several  methods  of  applying  this  test : 
A.  Mix  the  oil  with  j%  part  of  its  volume  of  a  solution  of  4  oz.  mer- 
cury in  8  oz.  6  dr.  nitric  acid  of  the  specific  gravity  of  1*5. 
B.  Make  a  mercurial  solution  by  dissolving  6  parts  mercury  in  7J 
parts  nitric  acid,  sp.  gr.  1*35  without  heat.  Then  add  1  part  of  this 
solution  to  every  48  parts  of  the  oil,  and  shake  it  well  every  30 
minutes,  until  it  begins  to  solidify.  A  temperature  of  90°  F.  will 
cause  the  oil  and  coagulum  to  separate  perfectly  from  each  other. 
3.  Add  to  the  oil  in  a  test  tube  a  small  globule  of  mercury,  or  some 
copper  turnings,  and  then  pour  in  nitric  acid.  If  the  olive  oil  is  pure, 
it  becomes  in  3  or  4  hours  after  the  application  of  these  tests,  like  a 
firm  fat,  without  any  separation  of  liquid  oil,  and  after  24  hours  the 
mass  will  be  found  so  hard  that  some  little  force  must  be  used  to  push 
a  glass  rod  into  it.  The  other  edible  oils  do  not  behave  in  this  way. 
The  solidity  of  the  mass  is  inversely  proportionate  to  the  quantity  of 
drying  oil  present.  When  the  sophistication  is  equal  to  \  of  the  whole 
a  distinct  layer  separates.  When  the  sample  contains  J  its  volume  of 
an  inferior  oil,  \  only  of  the  mixture  becomes  solid,  and  the  other  half 
remains  liquid.  When  the  adulterant  is  an  animal  oil,  the  mixture 
solidifies  in  about  5  hours. 
But  in  this  case  the  coagulum  contains  the  animal  oil,  whilst  the 
olive  oil  floats  on  the  surface,  and  may  be  decanted  off  for  further  ex- 
amination. The  coagulum  in  this  case  when  heated,  exhales  the  odor 
of  rancid  fat  or  tallow. 
Bach's  method  of  testing  olive  oil  with  nitric  acid :  5c.c.  of  sample 
are  shaken  in  a  convenient  tube  with  5  c.c.  of  nitric  acid,  sp.  gr. 
