THE  AMERICAN 
JOURNAL  OF  PHARMACY. 
JULY,  1884. 
BISMUTH  AN  J)  PEPSIN. 
By  R.  Bother. 
Considerable  uncertainty  still  exists  in  regard  to  the  constitution  of 
the  multiple  citrates.  The  writer  believes  to  have  elucidated  certain 
obscure  points  about  their  structure  and  to  have  greatly  simplified  the 
methods  of  their  production.  These  considerations  and  processes  are 
published  in  the  "American  Journal  of  Pharmacy"  for  March,  1876, 
April,  1876,  January,  1883,  March,  1883  and  April  1883.  It  is  there 
shown  that  in  case  of  the  iron  salts,  for  instance,  the  direct  application 
of  ferrous  or  ferric  citrate  is  vastly  more  definite,  practical  and  expedi- 
tious than  the  older  processes,  which  are  the  reverse  of  this.  The 
results  obtained  by  the  new  method  are  in  numerous  instances  chemi- 
cally identical  with  those  of  the  former  method,  and  in  the  remaining 
cases  a  close  approximation  to  them.  A  great  improvement  was  also 
made  in  the  production  of  bismuth  citrate,  and  as  an  immediate  con- 
sequence, in  that  of  the  ammonio-ch^u^  In  treating  of  this  latter 
compound  ("American  Journal  of  Pharmacy,"  March,  1876)  the  writer 
stated  that  a  crystalline  modification  of  it  exists.  On  this  occasion  a 
constitutional  formula  of  the  ammonio-citrate  was  given.  Subse- 
quently, however  "American  Journal  of  Pharmacy,"  March,  1 883), 
the  writer  was  enabled  by  means  of  a  different  method  to  establish  a 
more  accurate  formula.  The  fact  has  since  been  ascertained  that  the 
crystalline  salt  results  from  a  deficiency  of  ammonia  consequent  upon 
its  dissipation  by  the  action  of  heat  or  even  simple  exposure  at  ordinary 
temperatures.  The  writer  found  that  by  heating  one  m.  of  bismuth 
citrate  with  two  ms.  of  ammonium  bicarbonate  in  the  presence  of  about 
ten  times  their  weight  of  water,  a  perfect  solution  rapidly  results, 
attended  by  copious  effervescence  of  carbonic  anhydrate.  By  augment- 
ing the  citrate  further  combination  takes  place  and  thus  generates  the 
crystalline  compound  above  referred  to.  A  further  increase  of  the 
the  citrate  is  also  absorbed,  whilst  the  compound  becomes  more  and 
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