PREPARATION  OF  BITTER  ALMOND  WATER. 
159 
have  also  occurred  in  France,  where  it  is  still  largely  prescribed, 
and  the  preparation  of  a  water  of  uniform  strength  has  been 
made  the  subject  of  some  investigations  by  MM.  Ilepp  and 
Schlagdenhauffen.*  The  experiments  of  M.  Hepp  have  proved 
that  a  water  of  a  constant  strength,  containing  1  per  cent,  of 
Majcndie's  hydrocyanic  acid,f  is  obtained  when  from  a  given 
weight  of  bitter  almonds  an  equal  weight  of  water  is  distilled. 
Out  of  fifty-two  estimations  forty-seven  gave  exactly  1  per  cent, 
of  the  acid,  or  very  near  to  it. 
In  order  to  obtain  the  whole  of  the  hydrocyanic  acid  which 
bitter  almonds  are  capable  of  furnishing,  it  is  important  to 
facilitate  the  solution  of  the  amygdalin,  and  submit  it  to  the 
action  of  the  emulsine  under  conditions  the  most  favorable  to 
the  fermentation.  The  proportion  of  water  necessary  to 
promote  the  action  of  the  emulsine  on  the  amygdalin  is  not 
less  than  ten  times  the  weight  of  the  almonds  employed.  The 
almonds  deprived  of  their  fatty  oil  must  be  finely  powdered,  and 
allowed  to  ferment  for  three  days,  before  the  mixture  is  sub- 
mitted to  distillation.  Three  days  are  necessary  for  the  pro- 
duction of  the  whole  of  the  hydrocyanic  acid,  and  the  hydruret 
of  benzule  which  accompanies  it  after  three  days. 
M.  Schlagdenhauffen  has  assured  himself  by  experiment  that 
no  more  hydrocyanic  acid  is  produced,  but  beyond  this  lapse  of 
time  a  period  arrives  when  the  amount  of  acid  begins  to  diminish. 
The  still  employed  must  be  furnished  with  a  false  bottom 
perforated,  and  should  not  be  more  than  half  filled.  The  heat 
must  be  applied  very  gradually.  Any  amygdalin  which  may 
have  escaped  the  action  of  the  emulsine  during  the  maceration 
will  now  be  acted  on,  and  after  the  distillation  it  will  bo  found 
that  the  residue  has  been  deprived  of  all  bitterness,  and  will  give 
no  more  hydrocyanic  acid  by  the  addition  of  an  emulsion  of 
sweet  almonds. 
After  ebullition  has  commenced,  the  fire  may  be  quickened 
and  the  distillation  hastened,  taking  care,  however,  to  cool  the 
worm  well,  and  collect  the  product  in  a  vessel  carefully  joined 
to  the  end  of  the  worm. 
*  Reportoire  de  Chemie  Pure  et  Appliquee,  October,  1863,  p.  379. 
f  Majendie's  acid,  we  believe,  contains  4  per  cent,  of  real  acid. — 
Ed.  C.  N. 
