y6  Extractum  Ipecacuanha  Liquidum.  {AFebruaryTi8a99m* 
mined  by  titration.  Owing  to  the  fact  that  when  chloroformic 
solutions  of  the  alkaloids  of  ipecacuanha  are  evaporated  the  solu- 
tion rapidly  darkens  and  a  colored  residue  is  obtained,  it  was  found 
necessary  to  carry  out  this  operation  in  a  very  dilute  solution,  and 
in  order  to  obtain  strictly  comparative  results  exactly  the  same 
conditions  were  observed  in  every  case.  Each  residue  was  dissolved 
in  io  grammes  of  rectified  spirit  and  diluted  with  600  grammes  dis- 
tilled water.  Excess  of  N-10  H2S04  solution  was  then  added,  and 
the  mixture  titrated  back  with  N-100  NaOH  solution,  using  tincture 
of  cochineal  as  indicator.  The  number  of  cubic  centimetres  of  soda 
solution  required  was  divided  by  ten  and  subtracted  from  the  num- 
ber of  cubic  centimetres  of  acid  added,  giving  the  following  figures : 
Official  Method— 
No.  1  "386  equal  13*97  c.c.  N-10  acid. 
No.  2   '393  equal  14*18  c.c.  N-10  acid. 
Suggested  Method — 
No.  1  "417  equal  14*88  c.c.  N-10  acid. 
No.  2  '426  equal  15*24  c.c.  N-10  acid. 
The  residues  recovered  from  the  lead  precipitate  were  also 
titrated. 
No.  1     '031  equal  1*02  c.c.  N-10  acid. 
No.  2   "028  equal  1      c.c.  N-10  acid. 
From  these  figures  the  following  calculations  can  be  made,  show- 
ing that  within  the  limits  of  experimental  error  the  residue  yielded 
by  the  suggested  process  is  as  rich  in  alkaloid  as  that  of  the  official 
one : 
By  Official  Method  from — 
No.  1  assay  1  gr.  alkaloidal  residue  equal  .  .  .  .   36*2  c.c.  N-10  acid. 
No.  2  assay  1  gr.  alkaloidal  residue  equal  ....   36    c.c.  N-10  acid. 
By  Suggested  Method  from — 
No.  1  assay  1  gr.  alkaloidal  residue  equal  ....   357  c.c.  N-10  acid. 
No.  2  assay  1  gr.  alkaloidal  residue  equal  ....   35*8  c.c.  N-10  acid. 
As  far  as  can  be  seen  at  present,  titration  appears  useless  as  a 
means  of  estimating  the  alkaloids  of  ipecacuanha.  If  we  take  the 
molecular  weight  of  emetine  (248)  and  cephaeline  (234)  as  given  by 
Paul  and  Cowniey,  and,  assuming  these  alkaloids  to  be  present  in 
about  equal  quantity,  we  take  the  mean  of  their  molecular  weights 
(viz.,  241),  then  every  cubic  centimetre  of  N-10  acid  used  should 
correspond  to  .0241  grammes  of  the  mixed  alkaloids.    If,  however,. 
