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ON  NATURAL  ORGANIC  ALKALOIDS. 
endeavored  to  substitute  for  common  ether  a  solvent  capable  of 
obviating  this  inconvenience.  This  substitute  he  has  found  in 
acetic  ether,  which  dissolves  morphine  at  least  as  well  as  alcohol. 
After  devising  a  method  for  rectifying  commercial  ether,  he 
makes  use  of  this  solvent  in  the  following  way : — 
The  substances  to  undergo  examination  having  been  treated 
as  far  as  possible  by  Stas's  method,  he  adds  to  the  residue, 
already  exhausted  by  ordinary  alcohol,  a  certain  quantity  of 
potash  and  acetic  ether,  which  take  up  any  morphine  there  may 
be  remaining.  On  evaporating  separately  the  simple  etherized 
liquid  and  the  acetic  ether  liquid,  the  morphine  left  in  the  resi- 
due left  by  the  latter  is  recovered,  all  other  vegetable  bases 
being  included  in  that  which  furnishes  the  simple  ether.  At 
this  point  it  is  necessary  to  ascertain  whether  these  residues  are 
indeed  the  alkaloids.  Their  usual  reagents,  such  as  tannin, 
chloride  of  gold,  iodised  water,  phospho-molybdic  acid,  &c,  not 
being  exempt  from  drawbacks,  the  author  prefers  the  reagent 
used  by  M.  de  Vry  in  researches  on  atropine  and  strychnine  ; 
that  is  to  say,  double  iodide  of  mercury  and  potassium.  M. 
Valser  finds  it  possesses  the  invaluable  property  of  entirely  pre- 
cipitating alkaloids,  it  being  so  exquisitly  sensitive  to  their 
presence  as  to  indicate  tottooo  °f  strychnine  in  a  liquid.  More- 
over, this  double  iodide  precipitates  none  of  the  other  principles 
contained  in  the  vegetables,  except  the  albuminoid  matters  ; 
but  the  presence  of  these  matters  is  not  encountered,  since 
they  are  eliminated  by  the  ether  in  Stas's  process. 
These  facts  once  admitted,  the  author  makes  use  of  this  rea- 
gent, whose  general  utility  and  sensibility  is  incontestible,  to 
establish  the  presence  of  alkaloids  in  oils  of  belladonna,  hem- 
lock, &c,  which  before  was  only  suspected. 
The  second  part  is  devoted  to  researches  on  the  distinc- 
tive characteristics  of  alkaloids.  Finding  the  most  characteris- 
tic reactions  on  these  matters  produced  by  oxidising  bodies,  the 
author  tried  each  of  them  successively  at  various  temperatures ; 
sulphuric  acid  alone  or  associated  with  binoxide  of  barium  or 
binoxide  of  lead  ;  hydrochloric  acid  with  binoxide  of  barium  ; 
chloride  of  gold  and  caustic  potash.  With  each  he  elicited  dis- 
tinctive characters. 
The  third  part  comprises  a  study  of  the  estimation  of  alka. 
