REVIEW  OF  PHARMACOPCEA  HELVETICA.  315 
merely  the  purified.  Bromide  and  iodide  of  potassium  are  made 
by  Frederking's  process,  thereby  avoiding  the  very  tedious  wash- 
ing of  the  precipitated  protocarbonate  of  iron,  rendered  necessary 
by  following  the  process  of  our  pharmacopoeia. 
The  proportion  of  carbonate  of  potassa  and  sulphur  in  Kalium 
sulfuratum  is  3  :  2. 
The  preparations  of  magnesia  are  all  made  in  chemical  manu- 
factories ;  the  solution  of  the  citrate  is  not  officinal. 
In  Europe,  sulphate  of  morphia  is  very  rarely  used  ;  instead 
of  it,  the  more  soluble  acetate  and  muriate  are  officinal ;  like- 
wise the  pure  alkaloid  ;  only  the  latter  is  directed  to  be  made  by 
the  pharmacist. 
All  our  soda  salts,  except  the  sulphite,  are  officinal.  We  con- 
sider it  an  unnecessary  nicety  to  prepare  the  phosphate  from 
phosphoric  acid,  made  of  phosphorus. 
Plumbum  jodatum  is  still  prepared  from  acetate  of  lead ;  by 
the  use  of  the  nitrate,  the  loss  of  iodine  would  be  less. 
Plumbum  tannicum  humidum,  for  external  use  only,  is  obtained 
by  precipitating  a  decoction  of  oak  bark  by  subacetate  of  lead. 
The  preparations  of  antimony  correspond  with  our  officinal 
ones,  except  Stibium  sulfuratum  aurantiacum,  golden  sulphur, 
which  is  very  properly  made  and  obtained  of  uniform  composition 
by  the  decomposition  of  Schlippe's  double  salt  with  sulphuric  acid. 
Veratrinum,  Strychninum  nitricum  and  purum  are  made  in 
chemical  laboratories. 
A  great  loss  of  ether  and  alcohol  takes  place  in  the  prepara- 
tion of  tannic  acid,  Tanninum.  Eight  parts  of  galls,  in  coarse 
powder,  are  digested  with  twelve  parts  ether  and  three  parts 
alcohol ;  the  operation  is  repeated,  and  the  filtrate  is  mixed  with 
one- third  volume  of  water;  after  separation,  the  aqueous  liquid 
is  evaporated.  If  .the  first  part  of  the  process  of  our  pharma- 
copoeia is  followed,  the  loss  of  ether  is  comparatively  little,  since 
a  considerable  portion  may  be  recovered  by  distillation. 
To  obtain  cream  of  tartar,  free  from  lime,  Tartarus  depuratus 
is  prepared  by  digesting,  for  two  days,  ten  parts  of  powdered 
bitartrate  of  potassa  with  ten  of  water  and  one  of  muriatic  acid, 
and  washing  with  water. 
Tartarus  boraxatus.    Three  parts  Tartarus  depuratus  and  one 
