TESTING  OPIUM. 
369 
DETECTION  OF  PIGROTOXIN  IN  BEER. 
Kohler's  method  for  the  detection  of  picrotoxin,  the  active 
and  poisonous  principle  of  cocculus  indicus,  is  based  upon  the 
fact,  that  when  ammonia  is  present,  acetate  of  lead  precipitates 
as  insoluble  matter  from  beer,  such  substances  as  dextrin,  gum, 
glucose,  while  the  picrotoxin,  which  is  not  thus  precipitable,  can 
be  removed  by  means  of  ether  from  an  acidified  fluid.  The  beer 
to  be  tested  is  first  mixed  with  ammonia  until  it  is  distinctly 
alkaline,  the  ensuing  precipitate  of  phosphates  is  allowed  to 
settle,  and  after  the  fluid  has  become  clear,  a  boiling  hot  and 
concentrated  solution  of  acetate  of  lead  is  cautiously  added  as 
long  as  a  precipitate  ensues  ;  excess  of  lead  solution  should  be 
avoided.  The  precipitate  so  obtained  should  be  collected  on  a 
filter  and  washed  with  hot  alcohol  for  a  short  time ;  from  the 
filtrate,  the  lead  is  removed  by  means  of  sulphuretted  hydrogen 
gas,  the  sulphide  of  lead  removed  by  filtration,  and  the  filtrate 
evaporated  on  a  water-bath  to  the  consistence  of  a  syrup ;  the 
fluid  obtained  is  treated  with  ether,  the  latter  separated  from 
the  aqueous  residue,  and  the  ether  removed  by  evaporation. 
Picrotoxin  reduces  the  oxide  of  copper  to  protoxide,  is  soluble 
in  sulphuric  acid,  exhibiting  a  safi"ron  yellow  colored  fluid.  When 
bichromate  of  potash  is  added  to  the  sulphuric  acid  solution,  a 
violet  coloration  ensues,  which  ends  by  becoming  bright  green. 
If  the  beer  contains  strychnia  simultaneously  with  picrotoxin,  or 
extract  of  cocculus  indicus,  the  strychnia  remains  behind  in  the 
syrupy  fluid  which  remains  after  the  ether  is  separated  there- 
from by  means  of  a  stoppered  funnel. — Lond,  Chem,  News, 
Aprils,  1869; /rom  Zeitsch.  f.  Anal.  Chem. 
TESTING  OPIUM. 
Professor  Schneider  has  proposed  in  the  6th  revised  edition 
of  the  Pharmacopoeia  Austriaca,  the  following  method  for  test- 
ing the  goodness  of  opium.  Ten  grammes  of  previously  dried 
and  powdered  opium  is  treated  with  a  mixture  of  150  grammes 
^  of  distilled  water,  to  which  20  grammes  of  pure  hydrochloric 
acid,  sp.  gr.  1  12,  is  added  ;  the  residue,  after  extraction,  should 
not  exceed  4"5  grammes  weight ;  to  the  acid  fluid  20  grammes 
24 
