Am.  Jour.  Pharm.  \ 
March.  1899.  j 
Assay  of  Belladonna  Leaves. 
117 
the  extraction  with  15,  10  and  5  c.c.  of  the  solvent ;  while  this  last 
portion  is  separating,  run  the  other  portions  through  a  small  filter 
into  a  clean,  dry  flask  of  about  120  c.c.  capacity;  rinse  the  smaller 
separator  with  the  last  extraction  and  transfer  to  the  filter;  the  stem 
of  the  larger  separator  is  rinsed  with  5  c.c.  of  the  solvent  and  this 
portion  used  to  again  rinse  the  smaller  separator  before  transferring 
to  the  filter;  now  rinse  the  stem  of  the  smaller  separator  with  a  few 
cubic  centimetres  of  the  solvent,  allowing  this  portion  to  run  on  the 
filter,  and  wash  the  filter  and  funnel  with  several  small  portions  of 
solvent.  Any  aqueous  solution~transferred  to  the  smaller  separator 
should  be  prevented  from  getting  on  the  filter  and  the  latter  should 
be  covered  as  much  as  possible  to  prevent  evaporation  of  the 
solvent.  Should  an  emulsion  form  at  any  stage  of  the  extraction  of 
the  alkaline  solution,  add  a  small  fragment  of  stearic  acid  and 
manipulate  as  described  on  page  112. 
Distil  off  the  solvent  on  a  water-bath,  warm  until  the  odor  of 
chloroform  disappears,  dissolve  the  residue  in  5  c.c.  ether,  evaporate, 
redissolve  residue  in  5  c.c.  ether,  evaporate  and  heat  until  the  odor 
of  ether  disappears  ;  dissolve  in  8  c.c.  neutral  alcohol,  add  30  c.c. 
water  and  3  drops  hematoxylin  solution  and  titrate  with  stand- 
ardized HC1  to  the  disappearance  of  any  red  shade  or  the  formation 
of  a  pure  yellow  color. 
In  this  assay  process  in  which  so  much  inert  matter  is  present,  it 
frequently  happens  and  particularly  in  the  absence  of  stearic  acid 
that  a  pulverulent  yellow  precipitate  separates  from  the  alkaline 
solution  and  must  be  transferred  to  the  smaller  separator  and  from 
there  to  the  filter,  where  it  impedes  filtration. 
The  alkaloidal  residue  generally  has  a  light  greenish  color,  but 
this,  as  a  rule,  does  not  interfere  with  the  end  reaction  in  the  titra- 
tion ;  in  only  two  out  of  fourteen  assays  was  there  any  difficulty  in 
the  titration. 
It  is  unnecessary  to  make  more  than  the  following  comments 
upon  this  assay  process :  it  is  not  a  quick  process ;  it  has  for  its 
object  the  complete  extraction  of  the  alkaloids  from  a  definite  weight 
of  the  drug  or  preparation ;  one  of  its  most  important  uses  will  be 
the  determination  of  the  value  of  any  shorter  assay  process. 
The  results  on  page  120  were  obtained  by  this  assay  process : 
