ON  ACONITE. 
519 
stand  the  product  I  obtained  by  adding  ammonia  to  the  liquid 
containing  the  aconitine  in  the  presence  of  iodine,  and  washing 
with  sulphuric  ether,  nor  at  all  comprehend  why  an  alkali  of 
some  sort  did  not  precipitate  the  alkaloid  from  such  a  solution.  It 
appeared,  however,  that  the  hydriodate  of  aconitine  is  not  de- 
composable by  alkalies,  and  that  when  such  a  mixture  is  shaken 
with  abundance  of  sulphuric  ether  the  hydriodate  in  a  pure  state 
is  the  only  thing  taken  up.  An  additional  embarrassment  is 
felt  by  the  inutility  of  shaking  the  sulphuric  ether  holding  the 
hydriodate  in  solution  with  acidulated  water  with  the  view  of  re- 
covering the  alkaloid  as  a  muriate  or  nitrate. 
To  return  from  my  digression.  The  liquid  filtered  from  the 
iodide  of  silver  contains  now  nitrates  of  mercury,  of  silver  (in 
minute  quantity),  and  of  the  alkaloid,  and  the  latter  may  at  once 
be  obtained  in  a  pure  state  by  adding  an  excess  of  carbonate  of 
potash,  and  washing  two  or  three  times  with  ether.  But  I  pre- 
fer first  removing  the  mercury  by  sulphuretted  hydrogen,  as  it 
renders  the  washing  with  ether  so  much  easier  and  neater.  The 
ether  evaporated  or  recovered  by  distillation  leaves  a  residue  of 
a  pale  brown  color,  which  is  partly  crystalline,  partly  translucent 
like  a  fused  resin,  and  exhibits  a  strongly  alkaline  reaction.  On 
the  average  I  obtained  of  this  rather  more  than  ten  grains  per 
pound  of  root,  or,  making  allowance  for  that  remaining  in  the 
marc,  twelve  grains  per  pound. 
The  aconitine  is  then  dissolved  in  water  with  a  very  slight  ex- 
cess of  nitric  acid,  filtered,  and  set  aside  to  crystallize.  This  it 
commences  to  do  at  Once,  one-half  or  thereabout  of  the  aconitine 
being  so  obtainable.  I  find  it  crystallizes  much  more  easily  as 
nitrate  than  as  sulphate  or  hydrochlorate.  The  crystalline  form 
of  the  nitrate  appears  to  be  the  rhombic  prism,  commonly  with 
dihedral  summits.  They  readily  effloresce  when  heated,  losing 
their  transparency,  as  is  the  case  with  the  specimen  exhibited, 
which  was  accidentally  exposed  to  the  direct  rays  of  the  sun. 
The  nitrate  does  not  dissolve  readily  in  cold  water  ;  from  its 
solution  in  hot  water  it  crystallizes  with  unusual  facility. 
Tried  on  the  eye  of  a  cat,  it  produced  during  the  first  half-hour 
no  effect  beyond  irritation  of  the  neighboring  membranes  ;  after 
an  hour  it  caused  permanent  dilatation  of  the  pupil.    Its  color- 
