158 
PREPARATION  OF  BITTER  ALMOND  WATER. 
three  drops  of  a  very  dilute  solution  of  chloride  of  mercury  are 
now  added  to  the  distillate,  and  then  excess  of  solution  of  caus- 
tic potash,  and  the  whole  well  shaken.  If  the  precipitated 
oxide  of  mercury  does  not  redissolve  even  on  warming  the  liquid, 
wood  spirit  is  not  present ;  should  complete  solution  be  effected, 
however,  the  mixture  is  warmed,  and  divided  into  two  portions ; 
to  one  acetic  acid  is  added,  which  causes  the  formation  of  a 
yellowish-white  bulky  precipitate  ;  the  remaining  portion  is 
boiled,  and  a  similar  precipitate  is  thrown  down,  thus  proving 
with  certainty  that  wood  naphtha  is  present.  In  applying  this 
test,  it  is  necessary  to  be  careful  not  to  add  too  much  of  the 
mercurial  solution,  as  in  that  case  an  insoluble  compound  would 
be  formed,  and,  as  a  consequence,  a  negative  result  arrived 
at.*  When  practised  as  I  have  now  described,  I  look  upon  this 
test  as  being  safe  and  reliable  ;  at  least,  so  far  as  my  experience 
with  it  goes,  I  have  always  found  its  indications  to  be  correct, 
and  not  liable  to  the  ambiguity  occasionally  occurring  with  the 
potash  test.  I  make  this  statement  not  on  merely  theoretical 
grounds,  but  from  information  gleaned  in  the  course  of  a  series 
of  comparative  experiments  with  pure  tinctures,  and  those  pur- 
posely adulterated  with  wood  spirit.  I  trust  that  this  reaction 
may  prove  useful  as  a  means  for  the  detection  of  an  adultera- 
tion which,  I  am  sorry  to  say,  numerous  analyses  have  shown 
me  is  practised  to  some  extent  in  this  city.f — Lond.  Pharm. 
Journ.,  Dec,  1863. 
ON  THE  PREPARATION  OF  BITTER  ALMOND  WATElv. 
The  preparation  of  bitter  almond  water  of  a  uniform  strength 
is  a  matter  of  some  importance.  A  number  of  lamentable  acci- 
dents, caused  by  the  variation  and  uncertainty  of  the  strength 
of  this  preparation,  has  caused  a  useful  and  agreeable  medicine 
to  be  almost  entirely  disused  in  this  country.    Many  accidents 
*  It  must  not  be  forgotten  that  oxide  of  mercury  is  soluble  to  a  slight 
extent  in  potash  ;  but  such  a  solution  would  not  yield  a  precipitate  on 
boiling,  or  on  the  addition  of  an  acid. 
f  I  may  mention  that  "  cleaned  spirit"  is  capable  of  reacting  with  the 
mercurial  salt  in  a  manner  precisely  similar  to  the  ordinary  "methylated 
spirit." 
