Am.  Jour.  Pharm. 
May,  1884. 
Alkaloids  in  Belladonna  Root. 
283 
of  experiments  had  been  made  with  this  reagent,  and  also  in  reference 
to  the  decomposition  of  the  periodides,  we  devised  the  following 
method  for  estimating  the  purity  of  residues  of  atropine  and  hyoscya- 
mine.  The  alkaloidal  residue  is  dissolved  in  dilute  hydrochloric  acid 
and  to  this  liquid  is  added  excess  of  a  strong  solution  of  iodine  in 
potassium  iodide.  The  precipitate  which  at  once  agglomerates  is 
filtered  off,  slightly  washed  with  the  solution  of  iodine  and  decomposed 
upon  the  filter  with  a  solution  of  sodium  thiosulphate,  when  it  entirely 
dissolves,  forming  a  colorless  liquid  from  which  the  alkaloid  is  removed 
by  agitation  with  chloroform.  This  pTocess  gave  very  satisfactory 
results  with  pure  atropine,  and  the  following  results  were  obtained  with 
the  alkaloidal  residues  obtained  in  our  experiments : 
Residue  Pure  alkaloid 
taken.  found. 
1  0-020  0-0185 
2  0  019  0-0175 
3  0-078  0-079 
4  0-078  0-076 
These  figures  indicate  that  the  final  residue  of  alkaloid  obtained 
from  belladonna  root  by  the  process  which  we  have  described  consists 
of  pure  alkaloid.  It  should  be  noted  that  both  atropine  and  hyoscya- 
mine  are  much  affected  by  prolonged  exposure  at  100°C,  becoming 
sensibly  darker  in  color.  The  residues  of  alkaloid  obtained  in  the 
process,  and  which  usually  weigh  rather  less  than  0'1  gram,  are  light 
yellow  in  color  and  have  a  fused  appearance ;  crystals  of  the  alkaloids 
may  be  obtained  by  redissolving  in  chloroform  and  spontaneously 
evaporating,  when  silky  needles  will  remain  if  the  chloroform  was  free 
from  water.  The  following  is  a  detailed  description  of  the  process 
which  we  propose  for  the  estimation  of  the  atropine  and  hyoscyamine 
in  belladonna  root.  Twenty  grams  of  the  dry  and  finely  powdered 
root  are  exhausted  by  hot  percolation  with  a  mixture  of  equal  parts  by 
volume  of  chloroform  and  absolute  alcohol ;  if  an  extraction  appa- 
ratus is  used  about  60  cc.  of  the  mixture  is  required.  The  percolate 
is  agitated  with  two  successive  25  cc.  of  distilled  water,  which  are 
separated  in  the  usual  way.  These  are  mixed  and  well  agitated  with 
chloroform  to  remove  the  last  traces  of  mechanically  adherent  coloring 
matter.  The  chloroform  is  separated,  the  aqueous  liquid  rendered 
alkaline  with  ammonia  and  agitated  with  two  successive  25  cc.  of 
chloroform,  which  are  separated,  mixed  and  agitated  with  a  small 
quantity  of  water  (rendered  faintly  alkaline  with  ammonia)  to  remove 
