560 
Olive  Oil. 
f  Am.  Jour.  Pharm. 
\  November.  1901. 
This  oil  is  used  for  table  purposes  only,  while  that  obtained  from 
subsequent  pressings  of  the  residue,  and  which  is  a  very  inferior  oil, 
is  used  in  making  soaps,  liniments  and  lubricants. 
The  refuse  which  remains  after  the  oil  has  all  been  extracted  is 
used  as  a  fuel  or  for  manuring  purposes. 
THE  ADULTERATION  AND  PRESERVATION  OF  OLIVE  OIL. 
Fraud  is  often  practiced  in  the  manufacture  of  olive  oil,  by 
taking  olives  which  are  not  of  a  prime  quality,  or  which  have  be- 
come mouldy,  and  adding  leaves  of  the  olive  tree  or  seed  oil  to  the 
pulp  while  it  is  being  ground.    These  blend  perfectly  with  the  oil. 
To  keep  olive  oil  in  good  condition  the  clear  oil  must  be  sepa- 
rated from  the  turbid  at  once,  for  the  longer  it  remains  in  the  lees 
the  more  apt  it  is  to  become  rancid,  as  it  absorbs  oxygen  rapidly 
and  will  soon  reach  a  condition  unfit  for  food.  *  The  original  state 
can,  however,  be  restored,  as  a  general  rule,  by  washing  the  oil  with 
alcohol,  or  by  using  lime  water  in  equal  proportions.  It  congeals 
very  easily  when  exposed  to  a  low  temperature,  but  by  applying  a 
little  heat  it  will  return  to  its  original  liquid  state. 
VARIETIES  AND  TESTS   OF  OLIVE  OIL. 
Olive  oil  varies  greatly  according  to  its  physical  characteristics, 
the  finer  quality,  or  "  Virgin  oil,"  having  a  pale  yellow  color  with  a 
slightly  greenish  tinge  and  only  a  very  delicate  odor,  while  inferior 
qualities  have  a  more  pronounced  greenish  color,  a  very  unpleasant 
odor  and  a  decidedly  acrid  taste. 
The  specific  gravity  of  olive  oil  varies  from  0-915  to  0-918  at  15  0 
C.  When  heated  to  about  120°  it  becomes  lighter  in  color;  at 
220°  it  is  almost  colorless,  and  at  31 5°  it  boils  and  produces  a  very 
disagreeable,  rancid  odor. 
One  of  the  principal  adulterants  is  cottonseed  oil,  but  rape  oil  is 
also  used  to  a  very  large  extent.  Olive  oil  is  slightly  soluble  in 
alcohol  and  dissolves  very  readily  in  ether,  chloroform  or  carbon- 
disulphide. 
One  of  the  best  tests  for  olive  oil  is  the  following,  called — 
BECHI'S  TEST. 
If  5  c.c.  of  the  oil  be  thoroughly  shaken  in  a  test-tube  with  5  c.c. 
of  an  alcoholic  solution  of  silver  nitrate  (prepared  by  dissolving  ^ 
