558 
Preparation  of  Dialysed  Iron, 
(  Am.  Jour.  Pharm. 
t      Nov.,  1877. 
more  slowly,  when  the  test  solution  in  a  capsule  was  placed  under  a 
small  bell  glass  and  exposed  for  some  time  to  the  vapor  of  different 
essential  oils  emanating  from  cotton  wadding  on  which  they  had  been 
dropped,  or  from  a  little  vessel  containing  them.  In  some  few 
instances,  however,  by  using  the  test  in  this  way,  it  enabled  me  to  dis- 
tinguish very  quickly  the  pure  oil  from  the  same  kind  which  had  been 
mixed  with  a  minute  quantity  of  alcohol,  and  it  may,  therefore,  in  some 
cases  be  of  use  in  detecting  such  adulteration,  or  at  least  in  distin- 
guishing differences  in  various  samples  of  the  same  description  of  oil  ; 
but  I  found  that  this  way  of  employing  the  test,  though  much  simpler, 
was  not  so  generally  applicable,  nor  so  trustworthy  in  its  indications, 
as  the  method  already  described. — Pharm.  fourn.  and  Trans. ,  Sept. 
15th,  1877.   
ON  THE  PREPARATION  OF  DIALYSED  IRON. 
By  E.  B.  Shuttleworth. 
As  there  appears  every  possibility  that  dialysed  iron  will  become  quite 
popular,  at  least  for  a  time,  a  few  practical  directions,  unincumbered  by 
unnecessary  facts  or  speculations,  may  serve  a  useful  purpose. 
Many  methods  and  modifications  of  methods  have  been  proposed  for 
obtaining  the  solution  for  dialysis,  and  most  of  them  may  be  followed 
successfully.  The  .  object  is  to  prepare  a  solution  tolerably  concen- 
trated, fully  saturated  with  ferric  hydrate,  and  containing  as  little  acid 
as  possible.  I  shall  describe  two  methods,  each  of  which  has  its  pecu- 
liar advantages.  Where  time  is  not  an  object,  as  far  as  duration  of  the 
process  is  concerned  ;  and  also  in  point  of  economy  of  labor  and  mate- 
rials, the  first  may  be  adopted.  Where  it  is  desirable  to  produce  a  solu- 
tion that  may  be  finished  quickly  by  dialysis,  the  second  process  has  the 
advantage,  and,  taken  altogether,  I  believe  it  to  be  the  best. 
The  first  consists  in  adding  ammonia  to  a  solution  of  perchloride  of 
iron  so  long  as  the  precipitate  formed  is  redissolved.  A  solution  is 
produced  which  contains  ferric  hydrate  dissolved  in  ferric  chloride,  with 
free  chloride  of  ammonium.  Either  the  Liq.  Ferri  Perch  lor.  fort.  B.  P., 
or  the  Liq.  Ferri  Chloridi,  U.  S.  P.,  may  be  conveniently  used,  and  the 
liq.  ammoniae,  sp.  gr.  -959  or  '960,  of  either  pharmacopoeia,  will  be 
found  a  convenient  strength.  It  will  be  remembered  that  this  is  made 
by  adding  to  the  strong  ammonia  of  commerce  about  twice  its  bulk  of 
distilled  water.    If  the  ammonia  be  added  to  the  stronger  solution  of 
