PUKIFICATION  OF  ESSENCE  OF  ALMONDS. 
351 
PURIFICATION  OF  ESSENCE  OF  ALMONDS. 
By  Mr.  T.  B.  Groves. 
The  case  of  poisoning  by  bitter  almonds,  which  occurred  some 
months  back  in  London,  has  once  more  directed  the  attention  of 
Chemists  to  the  means  of  depriving  the  oil  of  its  poisonous 
character. 
The  pure  oil  is  known  to  be  innocuous,  at  least  as  much  so  as 
any  merely  irritating  oil  can  be,  and  that  its  poisonous  nature  is 
entirely  owing  to  a  contamination  of  prussic  acid,  which  the  oil 
contains  in  addition  to  benzoic  acid,  benzoine,  &c.  The  propor- 
tion of  prussic  acid  varies  much,  some  samples  containing,  as 
stated  by  Taylor,  twice  as  much  as  others,  or  even  more.  Turner 
states  it  to  be  12.6  per  cent.,  others  eight  or  ten,  at  any  rate  it 
may  be  said  to  be  from  four  to  six  times  the  strength  of  the  acid 
of  the  London  Pharmacopoeia.  The  oil  itself  is,  I  believe,  seldom 
sold  without  dilution  with  spirit,  except  as  a  scent  for  pomades, 
in  which  case  the  presence  of  prussic  acid  would  be  of  no  import- 
ance. Instances,  however,  have  occurred,  when  it  has  been  sold 
as  almond  flavoring,  although  ill  adapted  for  the  purpose,  and 
fatal  accidents  have  resulted.  The  smallest  quantity  known  to 
have  produced  fatal  effects  is  stated  by  Taylor  to  be  seventeen 
drops ;  the  largest  quantity  from  which  the  patient  recovered 
thirty  minims.  The  importance,  therefore,  of  purifying  it  is 
evident.  The  usual  almond,  ratassia  or  peach  kernel  flavor,  is 
made  by  dissolving  one  part  of  the  oil  in  seven  or  nine  parts  of 
rectified  spirit.  I  prefer  the  latter  proportion,  and  the  essence 
is  more  manageable,  and  should  be  mixed  in  the  convenient  pro- 
portion of  one  drop  of  essence  to  one  ounce  of  liquid  to  be  fla- 
vored. In  order  to  purify  the  oil,  and  to  do  away  with  the  dan- 
ger attendant  on  its  use  in  the  crude  state,  it  is  recommended  to 
distil  it  from  a  mixture  of  proto-chloride  of  iron,  lime  and  water. 
To  these  ingredients  Mr.  Redwood  adds  peroxide  of  mercury, 
and  states,  that  without  this  the  whole  of  the  acid  is  not  re- 
moved. The  mixture  cannot  be  distilled  from  a  glass  retort,  on 
account  of  the  violent  burnings  that  would  occur — a  copper  or 
other  metal  still  is  indispensable  for  the  purpose.  On  account  of 
the  troublesome  nature  of  the  operation,  the  loss  sustained,  and, 
above  all,  the  fact  that  nine  chemists  out  of  ten  do  not  possess 
