14  Emetine  Octoiodide  and  Alkaloids.  {^SyfistS™" 
The  number  of  cubic  centimetres  required  subtracted  from  io 
(cubic  centimetres  of  acid  used)  gives  the  number  of  cubic  centi- 
metres of  acid  saturated  by  alkaloids,  and  this  number  multiplied 
by  the  mean  of  the  molecular  weights  of  the  two  alkaloids  (0  0334 
-f-  O  0394  -f-  2  =)  0-0364,  gives  the  amount  of  alkaloids  obtained 
from  the  10  grammes  of  nux  vomica,  the  strychnine  and  brucine 
being  assumed  to  be  present  in  equal  proportions. 
Then  as  10  is  to  the  product  from  10,  so  is  100  to  the  percent- 
age of  the  mixed  alkaloids. 
J   ■ 
EMETINE  OCTOIODIDE  AND  THE  EXTRACTION  AND 
ESTIMATION  OF  ALKALOIDS  GENERALLY. 
By  H.  M.  Gordin  and  A.  B.  PrescoTT.1 
In  a  previous  paper2  we  have  shcfwn  that  most  alkaloids  form 
definite  compounds  when  treated  with  excess  of  iodo-potassium 
iodide,  and  that  it  is  possible  to  estimate  the  strength  of  aqueous 
solutions  of  alkaloidal  salts  by  means  of  standardized  solutions  of 
iodine  and  of  sodium  thiosulphate.  In  applying  this  method  to 
the  assay  of  medicinal  drugs  it  is  immaterial  what  method  of  ex- 
traction of  the  alkaloids  from  the  drug  is  employed,  provided  the 
final  alkaloidal  solution  be  sufficiently  deprived  of  non-alkaloidal 
matter.  The  simplest  and  quickest  method  of  obtaining  the  alka- 
loidal solution  sufficiently  free  from  foreign  matter  is  undoubtedly 
the  method  proposed  by  Dr.  A.  B.  Lyons.3 
This  consists  in  macerating  a  weighed  quantity  of  the  powdered 
drug  in  a  definite  volume  of  Prollius'  fluid  with  frequent  shaking 
for  several  hours,  drawing  off  an  aliquot  part  of  the  clear  liquid, 
evaporating  and  taking  up  the  residue  with  acidulated  water.  The 
alkaloidal  solution  obtained  by  this  method  is  generally  almost 
perfectly  colorless,  and  can  be  worked  up  further  for  a  gravimetric 
estimation  by  shaking  out  the  alkaloids  with  choloroform  and  am- 
monia. For  our  iodometric  method  the  filtered  solution  can  be 
treated  directly  with  excess  of  iodine,  the  excess  of  which  is  then 
estimated  by  sodium  thiosulphate.    For  the  alkalimetric  estimation, 
1  In  the  work  of  Research  Committee  D,  Section  2,  Committee  of  Revision 
and  Publication  of  the  Pharmacopoeia  of  the  United  States. 
2  J.  Am.  Chem.  Soc,  vol.  20,  p.  706,  Sept.,  1898. 
(<  Manual  of  Pharm.  Assaying,"  Haynes  &  Co.,  Detroit,  Mich.,  1886,  p.  20. 
