514  Alkaloids  and  Alkaloidal  Drugs.     { ^vemle^S' 
FURTHER  WORK  UPON  THE  ESTIMATION  OF  ALKA- 
LOIDS AND  THE  ASSAY  OF  ALKALOIDAL  DRUGS.1 
By  H.  M.  Gordin  and  A.  B.  Prescott. 
In  a  paper  presented  by  us  a  year  ago,2  we  offered  a  method  for 
the  volumetric  estimation  of  alkaloids  by  use  of  standard  solution 
of  iodine.  We  then  reported  upon  the  method  for  use  with  six  al- 
kaloids, morphine,  atropine,  strychnine,  brucine,  caffeine  and  aconi- 
tine.  And  we  had  succeeded  in  making  the  method  a  trustworthy 
and  convenient  one  for  five  of  these  alkaloids,3  all  those  just  named 
except  aconitine.  In  each  instance  we  had  obtained  in  purity  the 
higher  periodide  of  the  alkaloid,  the  one  formed  in  our  method  of 
estimation,  and  had  found  the  analysis  of  this  periodide  to  give  a 
molecular  factor  which  was  closely  verified  when  put  to  the  volu- 
metric test.  A  volumetric  method,  of  course,  requires  that  the 
alkaloid  be  first  brought  into  aqueous  solution,  nearly  free  from 
other  matters.  In  the  case  of  opium  we  had  reported  a  method  of 
extraction  from  the  crude  drug,  together  with  the  volumetric  esti- 
mation of  the  morphine,  in  one  assay  process,  having  advantages  of 
a  nearer  approach  to  complete  recovery  of  the  morphine  content, 
and  of  promptness  of  operation.  As  to  methods  of  extraction  for 
other  crude  drugs,  we  mentioned  a  year  ago  that  we  had  work  in 
hand,  and  said  that  it  was  too  early,  as  yet,  to  make  definite  propo- 
sals for  pharmacopcetal  adoption  of  the  method  for  any  of  the  alka- 
loidal drugs  or  galenicals. 
During  the  past  year  we  have  worked  upon  the  application  of  the 
iodometric  method  to  five  more  alkaloids,  emetine,  hydrastine,  ber- 
berine,  colchicine  and  quinine,  and  have  already  made  the  method 
entirely  satisfactory  for  emetine,  berberine  and  hydrastine.  For  ber- 
berine  the  estimation,  though  iodometric  in  one  sense,  rests  on  the 
formation  of  an  insoluble  hydriodide  instead  of  a  periodide,  and  re- 
1  In  the  work  of  Research  Committee  D,  Section  2,  Committee  of  Revision 
and  Publication  of  the  Pharmacopoeia  of  the  United  States,  1890-1900.  Read 
at  the  meeting  of  the  American  Pharmaceutical  Association,  September, 
1899. 
2  "  Certain  Alkaloidal  Periodides  and  the  Volumetric  Estimation  of  Alka- 
loids as  Higher  Periodides."  A.  B.  Prescott  and  H.  M.  Goidin,  "  Proc.  Am. 
Phar.  Assoc.,"  189S,  p.  355. 
3  For  caffeine  the  method  had  been  completed,  with  analysis  of  the  periodide 
and  other  perhalides,  by  Gomberg,  in  this  Laboratory,  in  1896. 
