I 
NOTE  ON  PURIFIED  ESSENTIAL  OIL  OP  ALMONDS.  135 
fluidounces,  the  remainder  of  the  twenty  fluidounces  being  lost 
by  evaporation. 
The  s.  g.  of  the  first  reserved  percolate,  namely,  the  tAvelve 
fluidounces,  is  -910  to  -912.  That  of  the  second  reserved  perco- 
late, namely,  the  sixteen  fluidounces,  is  *915.  That  of  the 
third,  namely,  the  twenty  fluidounces,  is  -912.  That  of  the 
whole  when  mixed  together  is  -914.  The  s.  g.  of  the  first  twelve 
fluidounces  of  the  three  percolations  is  '910,  -924,  and  -926.  In 
the  officinal  process  it  is  .914.  Each  four  fluidounces,  after  the 
twelve,  of  the  middle  percolation,  is  -887,  '873,  -867,  -862,  -855 
and  '848.  And  each  four  fluidounces  requires  about  two  hours 
to  pass  when  the  percolation  is  most  successful.  The  two  final 
portions  of  four  fluidounces  each,  set  away  for  the  next  making, 
have  specific  gravities  -867  and  -857. 
Although  one  percolator  is  sufficient  to  carry  out  the  process, 
the  time  may  be  considerably  shortened  by  the  use  of  two,  since 
the  second  one  may  then  be  packed  as  soon  as  the  second  por- 
tion of  the  percolate  from  the  first  is  received.  Flasks  marked 
to  the  measured  quantity  in  the  neck  should  always  be  used  to 
receive  the  percolate,  otherwise  the  evaporation  from  each  drop 
as  it  accumulates  in  a  slow  percolation  entails  great  loss. 
The  first  twelve  fluidounces  of  percolate,  both  in  the  officinal 
and  the  proposed  process,  must  represent  more  than  twelve  troy- 
ounces,  of  the  drug,  and  yet  its  s.  g.  is  far  below  that  of  the 
finished  officinal  preparation,  and  a  little  below  that  of  the  pro- 
posed preparation ;  thus  showing  that  s.  g.,  though  a  good  indi- 
cation of  exhaustion,  is  not  so  good  an  indication  of  medicinal 
value. 
The  avoiding  of  heating,  evaporating,  and  filtering  in  the 
proposed  process,  are  considered  to  be  of  primary  importance. — 
Proceed.  Amer.  JPharm,.  Assoc.,  1866. 
NOTE  ON  PURIFIED  ESSENTIAL  OIL  OF  ALMONDS, 
By  William  A.  Tilden,  F.  C.  S. 
Demonstrator  in  the  Laboratory  of  the  Pharmaceutical  Society  of  Great 
Britain. 
A  few  days  ago  I  came  upon  two  specimens  of  essential  oil 
of  almonds  which  I  had  prepared  in  1864  in  illustration  of  a  short 
