344 
Assay  of  Vallefs  Mass. 
Am.  Jour.  Pharm. 
July,  1898. 
pose:  1-1573  grammes  of  the  sample  were  treated  with  distilled 
water,  the  insoluble  matter  collected  on  a  plain  filter  and  washed 
with  distilled  water  until  honey,  sugar,  other  soluble  organic  and 
inorganic  substances  were  removed.  The  filter  and  its  contents 
were  then  transferred  to  a  beaker,  mixed  with  distilled  water,  and 
the  mixture  treated  with  diluted  sulphuric  acid  until  it  acquired  a 
distinct  acid  reaction  and  effervescence  ceased.  The  contents  of  the 
beaker  were  then  poured  on  another  plain  filter,  and  the  pulp  of  the 
first  filter  washed  on  the  same  with  distilled  water  until  the  wash- 
ings failed  to  react  with  potassium  ferricyanide  test  solution.  The 
mixed  filtrate  and  washings  were  then  titrated  with  decinormal 
potassium  permanganate  volumetric  solution  until  a  permanent  pink 
tint  was  imparted  to  the  liquid.  When  1-1573  grammes  of  the 
sample  are  taken,  each  cubic  centimeter  of  the  solution  represents 
1  per  cent,  of  ferrous  carbonate. 
A  sample  of  Vallet's  mass  made  in  strict  accordance  with  every 
detail  of  the  Pharmacopoeia  was  assayed  by  the  foregoing  method, 
for  the  purpose  of  learning  how  much  ferrous  carbonate  the  fresh  pro- 
duct prepared  in  this  manner  should  be  expected  to  contain.  Every 
care  was  taken  to  lessen  the  chances  of  oxidation,  which  invariably 
takes  place  to  a  greater  or  less  extent.  The  finished  product  was 
looked  upon  as  a  fair  sample  of  the  preparation.  It  contained,  on  an 
average,  38  66  per  cent,  of  ferrous  carbonate.  The  duplicate  analy- 
ses of  it  showed  3879  and  38-54  per  cent,  respectively. 
There  is  not  sufficient  sodium  carbonate  in  the  official  formula  to 
completely  change  all  of  the  ferrous  sulphate  directed  therein  to 
carbonate,  but  by  using  perfectly  pure  crystallized  sodium  carbonate 
(the  U.S. P.  directs  it  to  be  at  least  98  9  per  cent,  pure),  and  assum- 
ing that  it  is  totally  consumed  in  forming  ferrous  carbonate ;  also,  that 
all  of  the  latter  is  precipitated,  and  that  none  is  lost  mechanically 
or  oxidized  in  manipulation,  the  official  product  should  contain  40-54 
per  cent,  of  ferrous  carbonate.  But,  as  is  well  known,  it  is  quite 
impossible  to  fulfill  all  of  these  conditions,  and  it  is  probable,  there- 
fore, that  a  sample  showing  38-66  per  cent,  of  ferrous  carbonate  is  a 
fairly  good  product  of  the  process  when  carried  out  on  a  small 
scale. 
For  the  double  purpose  of  more  thoroughly  testing  the  suggested 
method  of  assay  and  of  gaining  some  knowledge  of  the  quality  of 
the  preparations  on  the  market,  specimens  were  procured,  from  four 
