278  Preparing  a  Hematin  Product.  {Amjineyi£iarm 
(4)  Decant  the  liquid  from  the  precipitate  as  completely  as  possi- 
ble. Fill  the  bottles  containing  the  moist  precipitate  with  cold 
water,  let  settle,  decant,  and  repeat  this  until  the  washings  give  only 
a  faint  turbidity  with  acidulated  T.  S.  silver  nitrate.  When  this 
stage  has  been  reached,  pour  the  precipitates  into  a  large  evaporat- 
ing dish  and  dry  on  a  boiling  water-bath.  Pulverize  the  product  in 
a  wedgewood  or  porcelain  mortar. 
IV.  YIELD  AND  CHARACTERS  OF  THE  PRODUCT. 
On  account  ot  the  low  cost  of  the  materials,  the  absolute  yield  is 
of  little  importance.  We  have  found  it  to  vary  from  1-8  to  3  per 
cent,  of  the  defibrinated  blood,  according  to  the  care  used  in  neu- 
tralizing and  in  decanting. 
The  product  constitutes  a  black,  granular  powder,  non-hygro- 
scopic, odorless,  and  practically  tasteless.  Mixed  with  sugar  or 
chocolate,  it  constitutes  a  very  palatable  confection. 
It  dissolves  slowly  in  1  per  cent.  Na2C03  and  in  0-2  per  cent.  HC1 ; 
less  readily  in  I  per  cent.  HC1.  The  solutions  are  turbid,  reddish 
brown,  and  give  the  characteristic  hematin  spectra.  The  solution  is 
hastened  by  heating.  The  solubility  is  not  impaired  by  boiling  the 
solutions  or  by  heating  the  dry  powder  for  twenty-four  hours  at 
100°  C.  Strong  NaOH  yields  a  clear  dichroic  solution,  which  does 
not  give  the  biuret  test  for  proteids.  The  hydrochloric  solutions  do 
not  give  the  Prussian-blue  reaction  with  ferrocyanide,  showing  the 
absence  of  inorganic  iron. 
The  ash  of  the  product  varies,  of  course,  with  the  care  with  which 
it  has  been  washed.  In  the  sample  made  by  Mr.  Young  it  was  9-2 
per  cent. ;  in  one  made  by  myself,  5  per  cent.  Dried  at  no0  C.  to 
constant  weight,  the  former  sample  lost  5*57  per  cent,  of  water. 
The  determination  of  the  ash,  moisture  and  iron  were  made  by 
Dr.  R.  A.  Hatcher.  I  take  this  opportunity  to  thank  him  for  his 
willing  assistance. 
V.   IRON- CONTENT. 
Two  different  samples  were  each  found  to  contain  07  per  cent.  Fe. 
Nencki  and  Sieber's  formula  for  hematin  (Cs2H32N404Fe)  corresponds 
to  9-3  per  cent.  Fe.  It  follows  from  this  that  my  product  is  far  from 
being  pure  hematin.  Nevertheless,  its  iron-content  compares  very 
favorably  with  that  of  other  iron  products.  Even  pure  hemoglobin 
contains  but  0-4  per  cent.  Fe  (Hufner). 
