160         ON  SOME  OF  THE  APPLICATIONS  OF  GLYCERINE. 
apply  pure  glycerine  in  some  pharmaceutical  preparations. 
Among  the  most  important  of  these  was  its  introduction  into  the 
Mistura  Ferri  Composita,  of  the  Pharmacopoeia,  for  the  purpose 
of  preserving  the  protocarbonate  of  iron  from  change.  In  the 
Pharmacopoeia  formula,  sugar  is  ordered,  from  the  well-known 
property  it  possesses  of  arresting  the  conversion  of  the  protosalts 
of  iron  into  persalts.  Mr.  Wilson  says,  in  experimenting  with 
pure  distilled  glycerine,  it  was  found  to  possess  this  property  of 
sugar  in  a  marked  degree,  together  with  another — that  of  dissolv- 
ing the  carbonate  of  iron  immediaetly  on  its  formation,  yielding 
a  deep  green  solution,  which  remains  unchanged  after  long  ex- 
posure to  light  and  air.  A  concentrated  Mistura  Ferri  Qomfo- 
sita,  eight  times  the  strength  of  the  Pharmacopoeia  preparation, 
may  be  made  by  dissolving  the  carbonate  of  potash  and  proto- 
sulphate  of  iron  in  separate  portions  of  glycerine,  and  mixing 
the  solutions.  At  the  moment  of  mixture,  the  protocarbonate 
of  iron  formed  is  dissolved,  forming  a  bright  green  solution. 
This  may  be  diluted  with  water,  and  the  powdered  myrrh  added 
when  required.  The  carbonate  of  iron  separates  on  dilution  as 
a  flocculent  precipitate. 
Glycerine  was  also  tried  as  a  substitute  for  sugar  syrup  of 
iodide  of  iron,  but  here  it  did  not  appear  to  answer  as  well  as 
sugar. 
Among  other  applications  that  were  suggested,,  were  the  fol- 
lowing : — 
Solution  of  ammonio-citrate  of  iron  in  glycerine,  in  the  pro- 
portion of  eight  grains  to  the  fluid  drachm. 
Solution  of  citrate  of  iron  and  quinine,  in  the  proportion  of 
two  grains  to  the  fluid  drachm. 
Solution  of  disulphate  of  quinine,  two  grains  to  the  fluid 
drachm,  no  addition  of  acid  being  required. 
Solution  of  the  alkaloid  quinine,  in  the  proportion  of  one  grain 
to  the  drachm. 
Solution  of  tannin,  eight  grains  to  the  drachm,  the  tannin 
being  thus  preserved  from  the  decomposition  which  occurs  in 
aqueous  solutions. 
It  was  suggested  that  essences  of  senna  and  rhubarb,  eight 
times  the  strength  of  the  Pharmacopoeia  infusions,  might  with 
advantage  be  made  with  glycerine,  the  latter  masking  the  taste 
