A  jaSy PS9rm"}    Emetine  '  Octoiodide  and  Alkaloids.  17 
sulphate.  The  amount  of  iodine  consumed,  multiplied  by  the 
suitable  factor,  gives  the  amount  of  alkaloid  present  in  the  quantity 
of  drug  taken. 
In  the  case  of  several  alkaloids  being  present  in  the  drug  a  mean 
iodometric  factor  can  be  deduced  in  the  same  way  as  is  done  in  the 
alkalimetric  assay.  It  is  to  be  noticed  that,  if  there  should  be  no 
precipitate  with  iodine,  but  only  a  slight  turbidity,  then  the  drug  is 
extremely  poor  and  for  the  assay  a  much  larger  quantity  than 
4  grams  should  be  taken.  On  the  other  hand,  if  after  adding  the 
alkaloidal  solution  to  the  iodo-potassium  iodide  solution  and  separ- 
ating the  periodide  by  shaking,  the  supernatant  liquid  should 
have  very  little  color  or  be  almost  colorless,  then  it  is  certain  that 
the  drug  is  very  rich,  and  either  a  smaller  quantity  of  the  drug  or  a 
larger  quantity  of  the  iodine  solution  must  be  employed  in  the  assay. 
The  method  of  extraction  described  above  presents  particular 
advantages  in  those  cases  where  several  alkaloids  soluble  in  different 
menstrua  are  present  in  the  drug,  as  by  using  these  menstrua  suc- 
cessively a  separation  of  the  alkaloids  can  be  easily  effected.  This 
principle  we  have  applied  to  the  assay  of  opium,  and  it  seems  also 
to  be  applicable  to  Hydrastis  canadensis,  upon  which  we  intend  to 
publish  a  report  in  the  near  future. 
This  method  of  extraction  of  alkaloids  for  assay  purposes  has 
given  us  very  good  results  with  all  drugs  experimented  upon,  except 
ipecac  root.  For  some,  unaccountable  reason  it  is  almost  impossible 
to  extract  completely  free  emetine,  which  is  liberated  in  our  process 
by  the  ethereo-ammoniacal  mixture,  from  this  root  by  percolation. 
Ether,  chloroform  and  acetone  were  tried  as  menstrua,  but  in  all 
cases  the  result  was  much  lower  than  that  obtained  by  Lyons'  pro- 
cess.10 Though  the  percolation  was  not  interrupted  till  a  few  drops 
tested  in  the  general  way  with  Wagner's  reagent  gave  no  reaction 
whatever,  the  very  low  result  as  compared  with  that  obtained  by 
Lyons'  method  shows  conclusively  that  the  exhaustion  cannot  be 
made  complete  by  percolation.  This  fact  would  possibly  explain 
why  Fliickiger,11  who  extracted  ipecac  by  percolation  with  ammo- 
niated  chloroform,  obtained  exceptionally  low  results. 
10  It  is  Lyons'  general  method,  not  his  modification  of  Dragendorff's  method, 
that  is  referred  to  here. 
nPharm.  Ztg.  1886,  No.  30.  See  also  Guareschi,  Einfiihr.  in  d.  Stud.  d. 
Alkal.    1896,  527. 
