612 
Iodine  in  Cod  Liver  Oil. 
/Am.  Jour.  I'harmk. 
I       Dec,  1883. 
IODINE  IN  COD  LIVER  OIL. 
By  Edward  C.  C.  Stanford,  F.C.S. 
"  It  is  proposed  to  verify  the  statement  in  Garrod^s  ^  Materia  Medica  ^ 
that  cod  liver  oil  contains  0*06  per  cent,  of  iodine.'^  See  "  Blue  List.^' 
If  this  statement  were  true,  cod  liver  oil  would  be  one  of  the  richest 
sources  of  iodine  with  which  we  are  acquainted.  At  present  the  marine 
algse  form  the  only  commercial  European  source  of  iodine.  The 
largest  quantity  of  iodine  found  in  the  deep  sea  tangle  or  stems  of 
Laminaria  digitata  amounts  in  the  fresh  plants  to  about  0*1  per  cent.. 
The  quantity  obtained  when  this  plant  is  burned  into  kelp  seldom 
reaches  0*05  per  cent.  The  average  yield  from  laminaria  drift  on  the 
large  scale  is  0*025  per  cent.,  but  many  thousands  of  tons  of  seaweed 
have  been  made  into  kelp  and  worked  for  iodine,  which  have  not 
yielded  more  than  0*005  per  cent.,  and  some  even  less  than  this,  so  that 
we  have  to  deal  on  the  large  scale  with  a  material,  and  constantly  to 
test  samples,  containing  very  small  percentages  of  iodine.  I  mention 
this  in  connection  with  the  process  daily  employed  for  many  years  in 
estimating  small  amounts  of  iodine  in  our  laboratory,  and  which  has 
also  been  employed  in  obtaining  the  results  from  cod  liver  oil  to  be: 
published  in  this  paper. 
Much  difference  of  opinion  has  arisen  amongst  former  observers  with 
reo^ard  to  iodine  in  cod  liver  oil,  and  the  statements  of  results  are 
extremely  conflicting,  some  chemists  having  failed  to  find  iodine  at  all,, 
others  only  in  some  specimens  of  this  oil.  Other  chemists  again  have 
estimated  the  proportion  of  iodine  as  much  higher  than  the  quantity 
above  indicated ;  and  it  has  been  assumed  that  this  element  represents 
an  important  factor  in  its  medicinal  value. 
In  a  well  known  work  on  materia  medica  the  editors  remark  that 
the  state  of  combination  in  cod  liver  oil  "  may,  perhaps,  tend  to  develop 
a  peculiar  action  of  iodine  and  bromine  and  endow  them  with  an  efficacy 
not  otherwise  attainable.^^ 
The  following  results  have  been  published  at  various  times  by  the 
authorities  quoted  : 
Iodine  per  cent.. 
Dorvault  found  in  cod  liver  oil  0*150 
Raie  found  in  cod  liver  oil  0*180 
Joseph  found  nearly  *  per  cent  0.487 
Machenroden  found  0*162  to  0  324 
Grager  found  in  light  brown  oil  0*0846 
Dr.  de  Jongh  found  in  pale  oil  0*0374 
pale  brown  0*040^ 
"  "  brown  0*0295 
All  these  are  extremely  high  and  improbable. 
