PURIFICATION  OF    THE  ESSENTIAL  OIL  OF  ALMONDS.  349 
of  silver,  and  subsequently  decomposing  the  resulting  cyanide  of 
silver  with  hydrochloric  acid.  Since  the  publication  of  Dr.  Mac- 
lagan's  paper  I  have  tried  this  process,  and  the  oil  obtained  by 
it  was  submitted  to  Dr.  Stenhouse  for  examination,  and  pronounced 
by  him  to  be  entirely  free  from  hydrocyanic  acid.  Whether  it 
be  innocuous  I  leave  to  be  decided  by  others. 
When  commercial  oil  of  bitter  almonds  is  mixed  with  a  solution 
of  nitrate  of  silver,  and  the  mixture  allowed  to  stand  for  some 
time,  crystals  of  cyanide  and  nitrate  of  silver  are  abundantly 
formed. 
Thirty-two  parts  of  the  crude  essential  oil,  sp.  gr.  1.079,  were 
redistilled,  and  received  into  a  solution  of  nitrate  of  silver,  when 
an  abundant  deposit  was  formed  containing  cyanide  of  silver. 
The  oil  was  collected,  added  to  a  second  portion  of  nitrate  of 
silver  in  solution,  and  again  distilled,  yielding  six  parts  of  a 
colorless  oil  of  sp.  gr.  1.051,  in  which  no  trace  of  hydrocyanic 
acid  could  be  detected.  This  oil  retains  the  flavoring  of  the 
bitter  almond. 
In  distilling  the  essential  oil  from  almond  cake,  three  oils  dif- 
fering in  density  are  obtained.  The  mixture  of  these  oils  is  opaque, 
but  becomes  bright  on  being  filtered.  These  results,  however, 
are  not  peculiar  to  the  production  of  almond  oil.  Sassafras  yields 
two  oils,  a  ste'aroptene  and  an  odorless  salt,  very  like  common 
alum  in  appearance,  but  perfectly  soluble  in  the  oils  from  which 
it  is  deposited.  This  stearoptene  is  deposited  like  the  crystalline 
matter  in  oil  of  almonds,  but  so  far  as  my  experience  has  gone, 
the  product  from  sassafras  is  always  the  same,  which  in  the  case 
of  the  almond  I  have  not  found  to  be  so.  The  largest  crystalline 
deposit  from  oil  of  bitter  almonds  that  has  come  under  my  notice 
was  of  the  consistence  and  color  of  honey.  This  when  washed 
with  alcohol  afforded  the  lemon-colored  crystals  which  were  ex- 
amined by  the  late  Dr.  Pereira,  and  a  specimen  of  which  is  among 
the  collection  of  the  Pharmaceutical  Society.  Another  remark- 
able deposit  which  I  obtained  from  oil  of  bitter  almonds  was  ex- 
amined by  Dr.  Faraday,  and  said  to  be  either  benzoic  or 
amygdalic  acid. 
Subsequently  on  using  steam  for  distilling  the  oil,  all  the 
crystalline  deposits  I  have  obtained,  which  have  been  examined 
by  Dr.  Stenhouse  and  others,  have  been  designated  benzoic  acid. 
