LIQUOR  BISMUTHI  ET  AMMONITE  CITRATIS. 
263 
tion,  deposits  well  formed  crystals  of  the  ternitrate.  These  may- 
be drained  on  a  funnel,  and  dried  by  exposure  to  the  air  on  a 
porous  tile,  or  on  white  filter  paper.  They  are  perfectly  definite 
in  composition,  having  the  formula  Bi  (N03)3,  5  H20,  and  they 
undergo  no  change  by  keeping.  By  long  exposure  to  the  air 
they  slightly  effloresce,  but  that  is  all.  If  the  salt  be  prepared 
from  commercial  bismuth,  a  second  crystallization  only  is  re- 
quired to  render  it  pure.  The  preliminary  purification  of  the 
metal  may,  if  desired,  be  thereby  dispensed  with.  995*15  grs. 
of  this  salt  contain  430  grs.  of  bismuth,  and  is,  therefore,  the 
quantity  to  be  used  in  lieu  of  the  metal  and  nitric  acid  ordered 
by  the  Pharmacopoeia. 
The  process  I  follow  is  arranged  for  a  gallon  of  liquor,  and  is 
as  follows : — 
Cryst.  ternitrate  of  bismuth    .    .    18J  oz.  (av.) 
Citric  acid  20  oz. 
Liq.  ammon.  fort  1  pint,  (Imp.)  or  q.  s. 
Distilled  water  q.  s. 
The  citric  acid  is  dissolved  in  two  pints  of  the  water,  and  the 
crystals  of  nitrate  added.  They  rapidly  dissolve,  and  after  a 
little  time  a  white  precipitate  begins  to  form.  As  soon  as  the 
nitrate  was  dissolved,  the  ammonia^  diluted  with  an  equal  bulk  of 
water  is  added,  little  by  little,  until  the  precipitate  is  dissolved, 
and  the  liquid  is  neutral.  The  resulting  solution  is,  if  necessary, 
filtered,  and  diluted  to  the  volume  of  one  gallon. 
It  will  be  observed  that  I  employ  rather  more  citric  acid  than 
the  P.  B.  orders.  This  I  find  to  be  desirable  when  the  crystals 
are  employed  in  lieu  of  the  nitric  solution. 
The  quantities  for  a  pint  are  as  follows  : — Ternitrate  of  bis- 
muth 995  grs.;  citric  acid  2J  oz.;  liq.  ammonise  and  water  q.  s. 
It  might  have  been  an  advantage  if  Mr.  Tichborne's  process 
had  been  given  in  the  Pharmacopoeia  instead  of  the  present  one, 
but  this  would  have  necessitated  the  introduction  of  the  crystal- 
lized ternitrate  as  a  distinct  preparation,  and  the  authors  may 
have  considered  that  confusion  would  arise  if  two  nitrates  of  bis- 
muth were  officinal. — Pharm.  Jown.,  March,  1868. 
