Am.  Jour.  Pharm.  ) 
May,  1880.  / 
Diffusive  Properties  of  Iron. 
273 
the  same  amount  of  iron  as  that  used  in  the  preceding  experiment, 
namely,  /\.0'i  grains  Fe.  Dialyzed  for  two  days  it  gave  a  diffusate 
yielding  34-9  grains  of  ferric  oxide,  and  in  four  days  more  it  gave  a 
further  difFusate,  yielding  14*2  grains  of  ferric  oxide,  thus  making  the 
amount  of  iron  as  ferric  oxide  49'i  grains,  corresponding  to  34*12 
grains  of  iron,  diffused  in  six  days,  or  85'3  per  cent,  of  the  iron  put  into 
the  dialyzer. 
The  experiment  vi^as  carried  on  for  two  days  longer,  when  a  further 
diffusate  was  obtained,  yielding  4'i  grains  of  ferric  oxide,  making  the 
total  amount  of  iron  diffused  in  eight  days  equal  to  93  per  cent,  of  the 
whole. 
7.  Chloride  of  Iron^  Ferrous  Chloride^  FeCl2.4H20.  —  A  lO  per  cent, 
solution,  100  grains  in  1,000  grains  of  solution,  dialyzed  for  two  days 
gave  a  diffusate,  yielding  33*96  grains  of  ferric  oxide,  and  dialyzed  for 
four  days  more  it  gave  a  further  diffusate,  vielding  4-3  grains  of  oxide, 
making  38*26  grains  of  ferric  oxide,  corresponding  to  26-8  grains  of 
iron,  or  95*7  per  cent,  of  the  iron  contained  in  the  dialyzer,  diffused  in 
six  days. 
8.  Perchloride  of  Iron^  Ferric  Chloride.  — 100  grains  of  ferrous  chloride 
converted  into  a  ferric  salt,  and  diluted  to  i^ooo  .grains,  gave  results 
nearly  coinciding  with  those  of  the  ferrous  chloride. 
On  comparing  the  results  of  the  foregoing  experiments,  it  will  be 
seen  that,  while  the  sulphates  and  chlorides,  and  especially  the  latter, 
stand  pre-eminent  in  regard  to  the  extent  and  rapidity  with  which  they 
undergo  liquid  diffusion  through  a  membrane,  it  cannot  be  said,  in  a 
medical  sense,  that  the  scaled  preparations,  and  especially  those  made 
•  with  citric  acid,  are  deficient  in  diffusibility,  for  the  latter  being  given 
in  much  larger  doses  than  the  former  would  be  absorbed  into  the  sys- 
tem to  fully  an  equal  extent. 
9.  Dialyzed  Iron.  —  Although  most  of  the  experiments  hitherto  des- 
cribed in  this  paper  were  made  simply  for  the  purpose  of  showing  the 
relative  diffusibility  of  preparations  of  iron  which  are  used  in  medicine, 
without  reference  to  dialyzed  iron,  and  of  ascertaining  how  far  the  dif- 
fusive property  of  such  preparations  is  affected  by  their  crystalline  or 
amorphous  condition,  yet  as  the  immediate  object  of  publishing  the 
results  at  this  time  was  to  show  that  the  scaled  preparations  of  iron  of 
the  Pharmacopoeia  are  not  subject  to  the  objections  which  have  been 
recently  urged  against  dialyzed  iron,  I  have  been  led  to  make  some 
experiments  with  the  view  of  ascertaining  how  far  the  properties  ascribed 
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