THE  SOLUTION  OF  PERCHLORIDE  OF  IRON,  ETC.  327 
salts  yield  a  faint  green  color  only  with  an  excess  of  daphnetine, 
which  thus  resembles  aesculetine.  Its  composition  isz=  Cgg  H^^ 
O^g;  its  compound  with  lead  =  Cog  H^q  Pb^O^g. 
On  the  dry  distillation  of  the  alcoholic  extract  of  mezereon, 
the  empyreumatic  distillate  separates  crystals  of  daphnetine  and 
umbelliferon,  the  latter  of  which  is  not  precipitated  by  acetate 
of  lead,  crystallizes  in  colorless  rhombic  prisms,  yields  with  water 
a  colorless  solution,  which  appears  beautiful  blue  in  reflected 
light  and  sublimes  below  its  fusing  point=240'^  C,  (464^  F.) 
While  it  is  remarkable  that  Dr.  Sommer  could  not  obtain  um- 
belliferon from  ammoniac,  a  gum  resin  of  an  umbelliferous  plant, 
it  is  not  less  remarkable  that  Daphne  mezereum,  a  plant  not 
allied  to  the  umbelliferse,  yields  this  product  of  decomposition. 
—Ann.  d.  Oh.  and  Ph.  xxxix.  1 — 18.  J.  M.  M. 
PROCESS  FOR  OBTAINING  THE  SOLUTION  OF  PERCHLORIDE 
OF  IRON  NEUTRAL  AND  UNALTERABLE. 
By  M.  Adrian. 
The  following  process  has  been  communicated  by  M.  Adrian 
to  the  Academy  of  Medicine,  for  obtaining  the  officinal  (Paris 
Codex)  solution  of  perchloride  of  iron  neutral  and  permanent : 
*'  This  process,  which  I  have  long  used  in  my  store  for  making 
neutral  solution  of  perchloride  of  iron,  is  very  simple.  It  con- 
sists in  preparing,  by  means  of  chlorohydric  acid  of  the  usual 
Paris  strength,  a  solution  of  proto-chloride  of  iron  marking  25° 
Baume.  To  avoid  all  peroxidation  of  the  iron  by  the  air,  this 
preparation  is  put  immediately  into  a  series  of  Woolf's  bottles, 
into  which  a  rapid  current  of  chlorine  (previously  well  washed) 
is  passed  during  about  five  or  six  hours.  This  time  suffices  usually 
to  convert  all  the  protochloride  into  sesquichloride  in  the  first 
bottles  which  receive  the  gas.  The  last  bottles,  which  are  not 
saturated,  are  then  put  in  place  of  the  first  and  these  filled  with 
a  new  portion  of  the  protochloride,  if  it  is  desired  to  render  the 
operation  continuous.  The  solution  of  perchloride  of  iron  is 
now  thrown  into  a  porcelain  capsule  and  heated  to  a  tempera- 
ture not  exceeding  122^^  F.  during  an  hour.  The  operation  is 
finished  by  passing  into  the  liquor  a  current  of  air  which  re- 
