176 
Bismuthi  Citras,  Etc. 
f  Am.  Jour.  Pharm. 
\      April,  1886. 
from  4  to  5  gallons  of  water  are  required,  and  with  less  acid  the  bis- 
muth is  apt  to  crystallize  out  before  water  can  be  added.  Mr.  Steph- 
enson's objection  is  alone  fatal  to  the  process,  but  I  believe  the  prin- 
ciple of  it  to  be  also  bad.  The  official  aim  is  to  bring  the  bismuth 
as  near  as  possible  to  the  basic  state  before  adding  the  alkaline  solu- 
tion. What  could  be  more  unreasonable?  We  require  a  normal  citrate 
and  try  for  an  oxycitrate !  I  have  obtained  a  citrate  free  from  nitrate, 
yet  not  wholly  ammonia-soluble,  and  this  I  take  to  be  due  to  oxyci- 
trate, the  reaction  between  the  basic  nitrate  and  the  oxycitrate  being — 
3  BiON03  +  H3C6H507  =  (BiO)3C6H507  +  3  HX03. 
In  this  case  this  is  a  subordinate  reaction,  no  doubt,  but  the  nature  of 
the  process  favors  it. 
We  have  the  same  error  of  principle  in  Rother's  process,  now  in 
the  U.  S.  Pharmacopoeia.  In  this  process  bismuth  subnitrate,  citric 
acid  and  water  are  boiled  together.  Here,  also,  though  the  subnitrate 
undergoes  complete  decomposition,  the  product  is  not  entirely  ammonia- 
soluble.  I  have  tried  repeatedly,  but  cannot  get  the  desired  result 
by  this  process,  and  others  in  whom  I  have  much  confidence  have  had 
the  same  experience. 
It  was  expected,  owing  to  the  introduction  of  oxide  of  bismuth 
into  the  1874  Addenda,  that  Wood's  process  would  have  been  adopted, 
and  Mr.  Umney  even  takes  the  new  process  as  Wood's,  but  it  is  not 
so.  In  Wood's  process  bismuth  oxide,  preferably  fresh,  is  dissolved 
in  a  mixture  of  solution  of  ammonia  and  ammonium  citrate.  This 
is  a  distinct  advantage  over  the  old  process,  but  it  has  an  objection,  viz., 
an  excess  of  ammonium  citrate,  which  we  know  to  be  unnecessary. 
In  a  paper  by  M.  Menu  (see  Am.  Jour.  Phar.,  1873,  p.  541),  we  have 
a  process  which  is  all  that  can  be  desired.  M.  Menu  dissolves  crystal- 
lized bismuth  ternitrate  in  a  strong  solution  of  citric  acid,  saturates 
one-half  of  the  mixture  with  ammonia,  then  adds  the  other  half  of  the 
mixture,  when  normal  bismuth  citrate  is  precipitated.  By  this  pro- 
cess, slightly  modified,  I  have  had  admirable  results.  The  citrate  is 
precipitated  in  a  bulky  condition,  and  when  dried  on  bibulous  paper 
in  a  hot  air  oven,  it  is  obtained  in  light  and  milk-white  flakes,  and 
forms  with  ammonia  a  bright,  almost  water-white  solution,  there  not 
being  a  particle  of  insoluble  residue.  Mehu  brings  the  process  for- 
ward ostensibly  for  the  direct  preparation  of  the  liquor,  but  as  his 
paper  does  not  contain  other  than  approximate  quantities,  I  give  a 
formula  for  a  pint  of  the  liquor. 
