408 
ON  LIQUOR  FERRI  IODIDI. 
Prom  the  various  examinations  which  have  been  undertaken 
with  this  oil,  it  seems  that  it  is  composed  of  two  different  oils, 
one  containing  oxygen  and  the  other  not.  The  first  belongs  in 
the  group  of  oils  composed  of  carbon  and  hydrogen  in  the  atomic 
relations  of  5  to  8,  which  group,  in  combination  with  hydrochlo- 
ric acid  gas,  forms  both  solid  and  liquid  compounds,  of  which 
turpentine  oil  is  the  type. 
ON  THE  CHANGES  TO  WHICH  LIQUOR  FERRI  IODIDI  IS  SUBJECT, 
AND  ITS  RESTORATION. 
By  J.  M.  Maisch. 
With  many  apothecaries  it  is  customary  to  cover  their  bottles 
and  vials  containing  the  solution  of  iodide  of  iron  with  dark 
colored  paper,  to  protect  it  from  the  action  of  light,  whilst  many 
others  do  not  deem  it  necessary  at  all.  The  practice  of  covering 
these  bottles  arises  from  the  supposition  that  the  light  has  a  de- 
cided effect  on  the  combination  of  this  solution,  by  gradually 
setting  iodine  free  and  depositing  sesquioxide  of  iron.  In  my 
own  experience  I  have  found  the  liquor  in  small  bottles,  well 
stopped  and  not  quite  full,  keeping  for  months  unprotected  from 
the  diffused  daylight  without  any  perceptible  change  of  color ; 
and  on  the  other  hand,  I  have  noticed  it  changing  to  a  dark 
orange  red  in  larger  bottles,  carefully  covered  with  dark  paper, 
which  had  to  be  opened  occasionally  to  dispense  their  contents 
according  to  prescriptions.  The  U.  S.  Pharmacopoeia  directs  it 
to  be  "  closely  stopped,"  and  the  U.  S.  Dispensatory  does  not 
mention  any  thing  about  the  action  of  light. 
Referring  to  the  American  Journal  of  Pharmacy,  I  find  in  vol. 
xiv.  page  59,  an  article  by  Dr.  A.  T.  Thomson,  which,  after 
speaking  of  the  consistency  of  his  "  thick  "  syrup,  has  the  follow- 
ing :  "It  is  unnecessary  to  preserve  the  syrup  in  stopped  bottles, 
or  to  seclude  it  from  light,"  and  "  this  syrup,  well  prepared,  un- 
dergoes no  decomposition  when  it  is  exposed  to  the  air  or  the 
light."  Messrs.  T.  and  H.  Smith,  in  the  Pharm.  Jour.,  (Am. 
Journ.  of  Pharm.,  1847,  102)  direct  it  to  be  kept  "  in  small 
vials  carefully  corked,  and  covered  with  dark  colored  paper." 
W.  Tozier  (Am.  Jour,  of  Pharm.,  1853,  58)  speaks  of  a  syrup  of 
iodide  of  iron,  which  in  8  fl.  ounces,  contains  7  oz.  of  sugar,  as 
