172 
SOLUTION  OF  CITRATE  OF  MAGNESIA. 
/' 
thing  more  natural  than  that  operators  should  follow  their  own 
inclinations  in  this  respect.  Hence,  we  see  those  who  invaria- 
bly adhere  to  the  pharmacopoeia,  where  such  a  possibility  exists^ 
prepare  but  a  few  bottles  of  it  at  a  time,  from  day  to  day,  as 
the  demand  requires.  In  this  case  the  preparation  is  not  finished 
until  called  for,  when  the  final  addition  of  the  potassium  carbo- 
nate is  made.  But  this  resort  is  very  impractical,  yet  it  is  the 
only  recourse  for  those  who  vow  allegiance  to  the  pharmacopoeia. 
Others,  out  of  ignorance,  substitute  magnesium  carbonate  for 
the  oxide  in  the  same  quantity,  and  thus  obtain  a  permanent 
solution  of  the  bimetallic  salt,  with  its  excessive  quantity  of 
acid.  Again,  others  see  fit  to  reduce  both  acid  and  oxide, 
usually  substituting  carbonate  for  the  latter,  upon  economical 
ground,  although  preserving  the  proportion  of  magnesium  by  the 
change.  A  solution  about  half  the  strength  of  the  officinal  keeps 
much  better,  in  their  experience. 
Yet,  by  far,  the  greater  number  do  not  dispense  magnesium 
citrate  at  all,  but,  under  the  pretence,  and  in  bottles  labelled 
magnesium  citrate,  variable  solutions  of  sodium  tartrate,  or  so- 
dium citrate,  either  alone,  a  mixture  of  the  two,  or  separately, 
but  contaminated  with  insignificant  admixtures  of  the  corres- 
ponding magnesium  salts,  are  largely  thrown  into  market,  and 
consumed  with  as  much  relish,  and  as,  apparently,  happy  effects, 
as  though  it  were  the  pure  citrate. 
Now,  since  the  sodium  tartrate  and  citrate  are,  therapeutical- 
ly, similar  to  the  corresponding  magnesium  salts,  and  in  them- 
selves stable  preparations,  and  much  cheaper  products,  there  is 
no  reason  why  they  should  not,  officinally,  replace,  in  whole  or 
part,  the  pharmaceutically  obnoxious  magnesium  compound. 
The  universal  desire  is  to  obtain  a  permanent  preparation  that 
is,  therapeutically,  identical  with  the  magnesium  citrate,  and 
can  either  replace,  or  pharmaceutically  modify  the  latter. 
We  know  that  a  solution  about  half  the  strength  of  the  offici- 
nal is  much  more  permanent,  and  that  this  permanence  is  ren- 
dered indefinite  by  a  sufficient  quantity  of  sodium  citrate;  and 
as  sodium  citrate  is,  therapeutically,  identical  with  the  former, 
and  equally  taseless,  there  exists  no  just  reason  that  can  prevent 
an  officinal  substitution  to  be  made. 
