4 
Dialyzed  Iron. 
(  Am.  Jour.  PhanoEi, 
"I       Jan.,  187^. 
The  capacity  of  this  apparatus  is  one  pint  and  a  quarter.  One  princi- 
pal point  in  its  favor  is,  there  being  quite  a  column  of  water  below  the 
dialisator,  ample  room  is  afforded  to  the  saturated  saline  solution,  which 
is  dialyzed  from  the  iron  solution,  to  settle  to  the  bottom,  and  thereby 
allow  fresh  portions  of  water  to  continually  come  in  contact  with  the 
septum,  consequently  facilitating  dialysis  considerably. 
Having  sufficiently  described  the  apparatus,  the  second  question  can 
now  be  considered,  viz.,  What  iron  solution  is  preferable  for  dialysis  P 
Two  solutions  only  were  experimented  with.  The  first  was  made  by 
dissolving  freshly  precipitated  oxide  of  iron  in  solution  of  chloride  of 
iron  to  saturation  ;  the  second  bv  adding  water  of  ammonia  to  solu- 
tion of  chloride  of  iron  so  long  as  the  precipitate  is  re-dissolved.  The 
first  solution  was  prepared  in  the  following  manner  :  4  fluidounces  of 
solution  of  tersuiphate  of  iron  were  added  to  sufficient  water  or 
ammonia  to  precipitate  all  the  oxide  of  iron.  The  magma  was  washed 
and  subjected  to  powerful  pressure  until  nearlv  all  the  water  had  been 
expelled,  and  a  hard  cake  was  left,  which  weighed  2  troyounces  and 
54  grains.  This  was  crushed  in  a  porcelain  mortar,  and  sufficient  solu- 
tion of  chloride  of  iron  was  added  (3  fluidounces)  to  effect  solution. 
It  was  accomplished  in  about  three  hours,  the  product  having  the  con- 
sistence of  a  thick  transparent  jelly.  After  standing  over  night  a 
change  had  taken  place  ;  the  transparency  of  the  jelly  had  given  place 
to  a  dull  liver  color.  The  appearance  was  as  if  a  portion  of  oxide 
had  separated  and  was  held  in  suspension.  In  reality  this  was  not  the 
case,  as  no  precipitation  occurred  upon  dilution,  neither  could  any  pre- 
cipitate be  separated  by  filtration.  In  thin  layers,  by  transmitted  light,, 
the  jelly  was  transparent,  but  by  reflected  light  opaque  or  dull  liver 
colored.  Diluted  with  distilled  water  to  8  fluidounces,  the  resulting 
solution  had  the  consistence  of  thick  syrup ;  4  fluidounces  of  this 
solution  was  placed  in  the  dialisator.  In  eleven  days  the  process  was 
completed,  and  the  resulting  solution  of  dialyzed  iron  measured  15. 
fluidounces.  It  still  retained  the  dull  liver  color,  and  100  grains, 
evaporated  to  dryness,  left  5  grains  of  solid  matter.  It  had  no  per- 
ceptible odor,  exhibited  no  astringency  to  the  taste,  and  gave  no  acid 
reaction,  but  after  one  month's  keeping  it  had  gelatinized,  and  because 
thorough  resolution,  by  the  addition  of  distilled  water  and  diligent 
stirring,  could  not  be  effected  ;  it  had  to  be  thrown  away.  The  remain- 
ing 4  fluidounces  of  syrupy  iron  solution,  after  standing  a  short  time, 
