166 
Ferric  Multiple  Citrates. 
( Am.  Jour.  Pharro. 
I       April,  1887. 
oils,  which  heretofore  have  been  difficult  to  distinguish  on  account  of 
similar  chemical  and  physical  tests,  (though  varying  greatly  therapeu- 
tically) can  now  be  readily  distinguished. 
At  the  request  of  Prof.  J.  U.  Lloyd,  I  am  now  engaged  making 
some  special  investigations  in  the  oils  of  fireweed  and  erigeron,  having 
distilled  them  in  twenty  fractions;  the  results  of  which  may  form  the 
subject  of  another  article. 
ISOMEEIC  FORMS  OF  FERRIC  MULTIPLE  CITRATES. 
By  R.  Rother. 
The  market  supplies  two  pretty  distinct  kinds  of  normal  ferric  cit- 
rate, as  the  writer  had  previously  pointed  out  (Amer.  Jour.  Phar,, 
Oct,  1885). 
It  is  not  implied  that  these  are  metameric  forms  of  one  another. 
The  ruby  tinted  kind  is  simply  an  impure  article  which  in  consequence 
of  extraneous  or  disproportional  admixture,  always  yields  an  apprecia- 
bly smaller  product  of  double  salt  than  is  theoretically  indicated.  But 
the  product  as  a  rule  does  not  materially  differ  in  character  from  that 
given  by  the  garnet  tinted  citrate. 
It  is  well  known  that  elixirs  containing  citro-salts  of  iron  with 
cinchona  alkaloid  salts  are  extremely  prone  to  discoloration.  Neither 
does  this  indicate  a  constitutional  transformation  of  the  iron  com- 
pound. The  effect  is  certainly  attributable  to  the  agency  of  the  acidic 
radicles  in  perverting  the  sugar  of  the  excipient,  the  alkaloid  or  both. 
Day  light  when  permitted  to  obtrude  is  doubtless  also  a  perceptible 
factor  in  the  case,  and  may  here  be  instrumental  in  reducing  the  iron 
to  the  ferrous  state  providing  no  means  are  present  for  retaining  or  re- 
converting it  as  ferric  salt. 
The  writer  has  elsewhere  (Amer.  Journ.  Phar.,  April  1883) 
pointed  out  that  the  constitutional  symbols  of  the  ferric  citro-salts  are 
legitimately  expressible  in  alternative  forms  rationally  indicative  of 
imtameric  products.  The  writer  has  succeeded  in  obtaining  at  least 
two  well  marked  compounds  of  this  nature.  When  for  instance  one 
molecule  of  ferric  citrate  previously  dissolved  in  water  by  means  of 
heat,  reacts  with  one  molecule  of  sodium  bicarbonate  the  compound 
constitutionally  symbolized  as  follows  results : 
(OH) — Fe=Ci — Na  (1) 
By  treating  this  sodio-ferric  hydro  citrate  with  one  m.  of  disodic 
