4 
ON  COD  LIVER  OIL. 
beautiful  red  color.  Its  chemical  composition  is  C25  H23  09.  Cod 
Liver  Oil  also  contains  about  sixteen  per  cent,  of  margaric  acid  ; 
nine  per  cent,  of  glycerin*  ;  a  small  proportion  of  butyric,  acetic, 
phosphoric,  and  sulphuric  acids ;  besides  traces  of  iodine,  bro- 
mine, iron,  lime,  soda  and  magnesia.  Iron  is  found  in  the  brown 
oil  only,  derived,  it  is  said,  from  the  iron  vessels  in  which  it  is 
manufactured.  This  statement  appears  doubtful  to  me,  as  large 
quantities  of  the  paler  oils  are  also  prepared  in  iron  vessels.  The 
brown  oils  contain  a  larger  amount  of  butyric  and  acetic  acids 
than  the  pale.  On  the  other  hand,  the  pale  varieties  contain  a 
larger  proportion  of  soda,  magnesia,  lime,  and  iodine.  The  reason 
ascribed  for  the  greater  quantity  of  salts  being  found  in  the  pale 
varieties  is,  that  this  part  being  first  separated  from  the  livers, 
dissolves,  and  carries  with  it  the  soluble  salts. 
In  regard  to  the  relative  value  of  the  different  varieties  of  oils 
for  medicinal  purposes,  physicians  differ.  Some  imagining  they 
had  seen  better  effects  derived  from  the  brown  oil  than  from  the 
white.  Others  again  could  perceive  no  difference.  Experience 
seems  to  shew  that  the  pale  oils  are  quite  as  effectual,  and  possess 
the  very  great  advantage  of  being  much  less  disagreeable  to  the 
palate,  and  Jess  liable  to  produce  nausea  when  swallowed.  Another 
objection  to  the  pale  oil  by  some  persons  is,  that  being  derived 
mostly  from  the  shore  fisheries,  it  is  more  mixed  up  with  oil  de- 
rived from  the  Gadus  Pollachius  or  Pollock.  This,  however,  need 
scarcely  be  an  objection,  as  it  is  now  generally  admitted  that  it 
is  not  necessary  that  the  oil  should  be  derived  from  the  Gadus 
Morrhua  alone,  as  the  oil  derived  from  all  the  varieties  of  this 
family  possesses  the  peculiar  medicinal  properties  in  nearly,  if 
not  quite  an  equal  degree. 
As  the  oil  used  for  medicinal  purposes  brings  a  much  higher 
price  than  the  ordinary  fish  oils,  a  great  temptation  is  held  out  to 
the  fisherman  and  dealer  in  oils  to  adulterate  the  officinal  article 
with  the  common  train  oil,  which  is  composed  of  a  variety  of  oils 
derived  from  fish,  which  are  generally  not  used  as  an  article  of 
food  by  man. 
*  [The  writer  had  not  seen  the  paper  of  Dr.  Winckler,  Am.  Jour.  Pharm. 
vol.  xxiv.  343, -who  has  shown  that  no  glycerin  exists  in  cod  liver  oil,  its  place 
"being  supplied  with  hjdrated  oxide  of  propyl,  a  distinguishing  feature  of  cod 
liver  oil. — Editor.] 
