52 
ON  THE  REVISION  OF  THE  U.  S.  PHARMACOPOEIA. 
as  for  thai  which  contains  no  chloride.  If  the  hydrochloric 
acid  be  of  full  officinal  strength,  it  will  contain  just  about  5  per 
cent,  of  chloride  of  silver. 
The  specimens  presented  are,  first,  that  made  by  Dr.  Smith 
containing  8  per  cent,  of  chloride  of  silver  added  in  the  form  of 
chloride  of  silver.  And  second,  that  made  by  the  writer  by  the 
above  formula. 
Ferri  Iodidum. 
In  the  management  of  this  preparation,  the  writer  greatly  pre- 
fers a  modification  of  the  process  of  Messrs.  Smith,  of  Edin- 
burgh, as  given  in  the  U.  S.  Dispensatory.  This  process  as 
now  used  by  the  writer,  reduced  to  the  scale  of  the  Pharmaco- 
poeia, is  as  follows: 
Take  of  Iodine,  two  ounces. 
Iron  Wire,  five  drachms. 
Distilled  Water,  three  fluid-ounces. 
To  the  iodine  and  water,  contained  in  a  glass-stoppered  bottle 
of  eight  ounces  capacity,  add  the  iron,  and  shake  the  mixture 
till  it  has  assumed  a  purely  green  color,  free  from  brown  tinge. 
Then  having  placed  a  flask  of  proper  capacity  over  a  spirit 
lamp,  or  gas-burner  which  is  just  ready  for  lighting,  filter  the 
solution  through  a  moistened  filter  into  the  flask,  allowing  the 
funnel  which  holds  the  filter  to  rest  upon  the  rim  of  the  flask 
neck.  As  soon  as  the  filtration  has  commenced,  light  the  flame 
beneath,  and  boil  the  solution.  When  the  solution  has  all  passed 
the  filter,  and  the  filter  has  been  washed  by  the  water  condensed 
from  the  boiling  solution,  remove  the  funnel  and  filter, 
and  introduce  a  long  piece  of  clean  iron  wire.  Boil  ac- 
tively till  the  iodide  begins  to  thicken,  and  then  gradually  re- 
duce the  flame,  and  continue  the  heating  gently  till  iodine  vapor 
appears  in  the  remaining  portions  of  watery  vapors  passing  off. 
Then  extinguish  the  flame,  and  allow  the  flask  to  stand  loosely 
stopped  for  half  an  hour  to  cool.  Finally,  break  the  flask  over 
a  warm  dry  mortar,  carefully  excluding  the  fragments  of  glass, 
break  up  the  iodide  and  transfer  it  to  small  bottles  with  good 
stoppers.    The  net  yield  is  1212  grains. 
Some  of  the  advantages  obtained  by  this  management  are  as 
follows  :    By  using  so  much  less  iron,  though  still  a  sufficient 
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