232  Expressed  Oil  of  Almonds.  {AmMay"'i889arm' 
following  statement :  On  mixing  one  part  of  oil  of  almonds  with 
four  parts  of  absolute  alcohol  and  immersing  the  test  tube  in  the 
water-bath  a  perfectly  clear  solution  is  obtained.  It  required  34  parts 
of  cold  absolute  alcohol  at  the  temperature  of  the  atmosphere  (about 
70°  F.)  to  make  a  perfect  solution.  With  alcohol  of  .820  sp.  gr.,  42 
parts  were  required  to  make  a  solution  at  the  boiling  point. 
Color  Reactions. — The  U.  S.  P.  gives  only  the  reaction  with  sul- 
phuric acid.  While  this  test  may  serve  to  indicate  the  adulteration 
with  cottonseed,  sesame,  peanut,  rape  and  poppy  oils,  it  would  not 
indicate  the  admixture  of  lard  or  olive  oils  or  the  entire  sophistication 
by  peach  or  apricot  kernel  oils.  The  Ger.  Ph.  introduces  the  follow- 
ing test  "  when  15  parts  of  the  oil  are  thoroughly  shaken  with  a  mix- 
ture of  2  parts  of  water  and  3  parts  of  fuming  nitric  acid,  a  whitish 
mixture  free  from  red  or  brown  color  should  be  formed  which  should 
separate  after  several  hours  into  a  firm  white  mass  and  a  nearly  color- 
less liquid.  This  test  will  serve  to  indicate  adulterations  with  peach 
kernel,  apricot  kernel,  sesame,  and  peanut  oil  if  present  in  consider- 
able quantity. 
The  reaction  with  an  equal  volume  of  hydrochloric  acid  and  a  frag- 
ment of  sugar  is  a  very  delicate  test  for  sesame  oil,  the  acid  liquid 
separating  of  a  bright  red  color  gradually  assuming  a  purplish  tint. 
While  testing  these  oils  with  this  test  it  was  observed  by  the  writer 
that  on  agitating  several  of  the  samples  with  an  equal  volume  of 
pure  hydrochloric  acid  (sp.  gr.  1.2)  the  oil  became  white  and  the  acid 
separated  assuming  in  a  few  minutes  a  bright  emerald  green  color. 
Thinking  that  this  might  possibly  be  due  to  some  metallic  impurities 
in  the  oil  the  acid  liquid  was  separated  and  tested  for  metals  with  a 
negative  result.  A  number  of  pure  oils  were  examined  to  determine 
the  cause  of  the  reaction,  but  none  of  them  would  give  similar  results. 
Various  mixtures  of  pure  oils  were  tried  and  from  these  the  conclu- 
sion was  derived  that  the  reaction  noted  was  due  to  a  mixture  of 
arachis  and  sesame  oils.  Pure  arachis  oil  gives  no  reaction  with 
hydrochloric  acid,  while  sesame  oil  gradually  assumes  a  reddish  color 
and  the  acid  becoming  also  of  a  faint  reddish  tint.  That  a  mixture 
of  these  oils  should  produce  this  reaction  has  I  believe  not  before  been 
observed.  Oxygen  seems  to  be  necessary  to  the  reaction  and  it  is 
noticeable  that  with  rancid  oils  the  reaction  is  more  distinct. 
The  following  table  exhibits  the  color  reactions  of  the  oils  and  also 
the  iodine  absorptions. 
