354: 
PURIFICATION  OF  ESSENCE  OF  ALMONDS. 
strength,  otherwise  those  who  had  been  accustomed  to  use  the 
weaker  preparation  in  considerable  quantity,  on  being  supplied 
with  the  stronger,  would  by  using  it  as  before,  incur  great  danger. 
This  danger  could  only  be  entirely  obviated  by  purifying  the  oil 
from  prussic  acid.  When  the  subject  was  brought  under  the 
notice  of  Pharmaceutical  Chemists  some  years  ago  by  Mr.  Grind- 
ley,  of  Chester,  who  was  then  a  pupil  in  the  School  of  Pharmacy, 
a  large  establishment  at  Liverpool  commenced  selling  essence, 
prepared  with  the  purified  oil,  but  this  was  afterwards  relinquished, 
the  public  giving  a  preference  to  the  essence  made  with  the  crude 
oil,  the  flavor  of  which  was  considered  to  be  better.  He  trusted 
that  the  subject  would  now  be  thoroughly  investigated  and  put 
upon  a  more  satisfactory  footing.  With  reference  to  the  difficulty 
experienced  in  distilling  the  essential  oil  in  glass  vessels,  which 
was  referred  to  in  Mr.  Grove's  paper,  he  would  mention  a  very 
easy  method  of  obviating  that  difficulty,  arising  from  the  bumping 
of  the  liquid,  which  was  to  coat  the  inside  of  the  glass  vessel 
with  silver.  This  may  be  very  readily  done  by  putting  into  the 
vessel  a  solution  of  nitrate  of  silver  rendered  slightly  alkaline 
with  ammonia  and  boiling  it  for  a  few  minutes  with  a  little  honey. 
The  vessel  should  not  be  used  for  a  few  days  after  being  thus 
coated,  otherwise  the  silver  would  be  liable  to  peel  off. 
Mr.  Greaves  stated,  that  at  the  request  of  Mr.  Whipple  he 
had  tried  the  effect  of  the  essential  oil  purified  by  the  process 
described  in  this  paper.  He  administered  forty  minims  to  a  cat, 
and  more  than  a  fluid  drachm  to  a  small  dog,  and  in  neither  case 
were  the  effects  different  from  those  which  any  ordinary  essential 
oil  would  produce,  and  from  which  the  animals  soon  recovered. 
Dr.  Normandy  observed  that  experiments  on  the  effects  of 
poisons  were  frequently  made  with  rabbits,  but  these  animals 
were,  from  a  peculiarity  of  their  organization,  quite  unsuited  for 
such  experiments.  These  peculiarities  sometimes  occurred  among 
animals.  Thus  it  is  well  known  that  common  parsley  wTas  a 
poison  to  parrots.  The  experiments  referred  to  by  Mr.  Greaves 
had  been  judiciously  made  upon  cats  and  dogs,  which  animals 
more  nearly  represented  man  in  the  manner  in  which  they  were 
acted  upon  by  poisons. 
Mr.  Pedler  thought  it  more  important  to  effect  the  purifi- 
cation of  the  oil  than  than  the  essence  of  almonds,  the  latter 
