AlApSr'i92iarm' }       Preparation  of  Nux  Vomica.  267 
simply  the  fact  that  the  quantity  of  alcohol  employed  is  notoriously 
insufficient  to  exhaust  completely  the  powdered  nux  vomica.  I 
have  already  shown,  in  my  thesis  for  Doctorate  in  Pharmacy,  that 
in  limiting  the  quantity  of  alcohol  at  70  per  cent,  to  only  six  times 
the  weight  of  the  drug,  a  month  is  necessary  in  order  to  extract  all 
of  the  alkaloids  of  nux  vomica,  provided  that  there  is  previously 
obtained  each  day,  by  the  method  of  macero-percolation,  a  weight  of 
percolate  equal  to  only  the  fifth  part  of  the  weight  of  the  drug,  the 
P 
velocity  V  of  macero-percolation  being  equal  to  —  .    In  complying 
to  the  rules  of  percolation  prescribed  by  the  Codex  (p.  383),  experi- 
ence proves  that  there  is  necessary  a  weight  for  dissolving  at  least 
equal  to  twice  the  weight  of  the  drug. 
II.  Cleaning  of  the  Liquid  Extract. — In  order  to  understand 
well  the  manner  of  this  delicate  operation,  it  is  necessary  to  read 
again  the  directions  of  the  Belgian  Pharmacopoeia  (1906  edition, 
page  218).  Here  some  of  it  is  explained:  "Extract  the  nux  vomica 
with  alcohol  and  concentrate  to  a  weight  of  200  gm.  If  the  liquid 
does  not  redden  litmus,  acidulate  it  with  acetic  acid.  Add  100  cc  of 
ether,  agitate  carefully,  decant  the  ether,  repeat  this  washing  as 
long  as  the  solvent  takes  up  oily  matter.  Evaporate  to  dryness  the 
product  thus  exhausted  by  the  ether."  These  few  lines  are  clear 
and  concise.  They  denote  that  the  liquid  extract  of  nux  vomica 
contains  at  the  same  time  oily  matter  and  alkaloids  (strychnine  and 
brucine)  in  the  state  of  neutral  salts  or  readily  acid  to  litmus.  If 
the  reaction  is  neutral  or  alkaline  (which  is  extremely  rare),  that 
proves  that  there  can  exist  in  the  liquid  extract,  free  alkaloids,  not 
salified,  which  will  risk  being  carried  away  by  successive  washings 
>f  the  ether.  It  is  necessary  therefore  to  begin  by  salifying,  if  there 
s  need  of,  these  alkaloids  by  a  sufficient  quantity  of  diluted  acetic 
icid,  after  which  the  washing  with  ether  can  be  effected  without 
fear ;  the  weight  of  the  alkaloids  carried  away  by  ether  should  be 
legligible.  It  is  advisable  to  place  the  flask  containing  the  mixture 
Df  liquid  extract  and  ether  in  a  freezing  bath,  in  order  to  avoid  the 
formation  of  an  emulsion.  It  is  admitted  to  be  less  precise  than 
that  of  the  French  Codex,  which  fixes  exactly  the  number  of  ether 
washings,  and  the  quantity  of  ether  to  employ  for  each  washing. 
Now,  that  quantity  is  almost  always  insufficient;  the  French  phar- 
