Am  Jour.  Pharm. 
Jan.,  1892. 
}  Preservation  of  Syrup  of  Iodide  of  Iron. 
19 
No  change  is  perceptible  in  the  syrup  from  prolonged  contact 
with  the  gas,  the  color  and  transparency  remaining  to  the  last. 
Several  methods  for  the  automatic  generation  of  the  gas  were 
tried,  and  the  two  simple  pieces  of  apparatus  shown  by  the  photo- 
graphs exhibited  were  found  efficient. 
A  bottle  of  about  the  same  size  as  the  syrup  bottle,  and  partly 
filled  with  dilute  sulphuric  acid,  is  connected  through  the  cork  by 
means  of  a  siphon  tube  with  a  smaller  bottle  containing  a  concen- 
trated solution  of  carbonate  of  sodium,  and  the  gas  is  supplied  to  the 
well-corked  syrup  bottle  by  another  tube  fitted  into  the  corks  of 
the  acid  and  syrup  bottles.  When  a  portion  of  syrup  is  drawn,  the 
partial  vacuum  formed  in  the  bottles  causes  the  solution  of  the 
carbonate  to  flow  over  into  the  acid,  generating  sufficient  gas  to 
replace  the  syrup  drawn  ;  the  excess  of  gas,  if  any,  escaping  through 
the  siphon  tube  and  the  carbonate  solution.  In  another  apparatus 
of  more  recent  construction,  the  gas  is  kept  under  slight  pressure 
by  the  weight  of  the  liquid  in  the  tube  B  and  reservoir  C  as  shown 
in  the  line  diagram,  which  clearly  shows  its  construction. 
I  find  the  specific  gravity  of  the  officinal  syrup,  very  carefully 
made,  and  accurately  tested,  to  be  1-429. 
Sharon,  Pa.,  Dec.  14.,  i8gi. 
