Am.  Jour.  Pharni.  ) 
Jan.,  z279.  J 
Dialyzed  Iron. 
1 
descending  from  the  point  of  the  septum  to  the  bottom  of  the  perco- 
lator. This  lasts  several  days.  If  thin  paper  is  used,  this  band  will 
assume  a  considerably  larger  diameter  and  descend  faster,  showing  that 
the  crystalloid  is  separated  more  copiously  than  before.  Another  point 
which  deserves  some  attention  is  that  from  the  outset  the  iron  solution 
in  the  dialisator  increases  in  bulk  to  an  almost  definite  quantity.  If 
evaporation  has  been  prohibited  by  placing  a  lid  on  the  apparatus,  the 
resulting  product  will  have  increased  from  9  fluidounces  to  between  16 
and:  17  fluidounces,  and  always  contain  5  per  cent,  of  solid  matter. 
This  is  certainly  very  convenient,  because  it  does  away  with  the  extra 
work  of  diluting  a  too  concentrated,  or  concentrating  a  too  dilute 
product,  especially  the  latter,  if  conducted  by  spontaneous  evaporation, 
being  a  most  tedious  process. 
Does  the  use  of  distilled  or  rain  water,  in  dialysis,  assure  a  better 
and  medicinally  purer  preparation  than  that  of  common  well  or  hard 
water?  No.  Well  water  has  been  used,  except  in  the  first,  in  most 
all  the  processes  described.  As  is  well  known,  if  common  hard  water 
is  mixed  with  dialyzed  iron,  precipitation  ensues  ;  consequently,  if  the 
iron  solution  were  contaminated  by  hard  water  during  dialysis,  precipi- 
tation ought  to  take  place. 
This  it  does  not.  The  water  used  was  taken  from  a  well  blown 
into  the  rock,  principally  composed  of  carbonate  of  calcium.  When 
oxalate  of  ammonium  is  added  to  the  water  a  copious  precipitate  results. 
When  the  dialyzed  iron  is  first  precipitated  by  ammonia,  and  oxalic 
acid  is  added  to  the  filtrate,  no  precipitate  occurs.  From  this  it  is 
apparent  that  although  common  well  water  cannot  be  used  for  the 
purpose  of  diluting  solution  of  dialyzed  iron,  it  can  be  used  in  dialysis. 
To  recapitulate  :  if  an  apparatus  is  employed,  arranged  in  such  a 
manner  that  fresh  portions  of  water  continually  come  in  contact  with 
the  septum  ;  if  the  iron  solution  can  be  made  in  a  short  time  ;  if  parch- 
ment paper  of  the  proper  thickness  is  used  ;  if  evaporation  is  dispensed, 
with,  and  if  proper  care  is  taken  that  the  product  does  not  become 
too  dilute,  a  5  per  cent,  solution  of  dialyzed  iron  measuring  1  pint  may 
be  prepared  in  5  days. 
Lowell,  N.  St.  Louis,  Mo,  Nov.,  1878 
