18 
Acidum  Oleicum. 
f  Am.  .lour.  Pharm 
t       Jan.,  1884. 
saponification,  is  doubtless  partly  due  to  the  palmitic  acid  present  in 
the  first,  and  entirely  absent  in  the  last  portion. '  But  the  boiling  oil  of 
so  much  vapor  in  the  heating  of  the  latter  portion,  and  the  consider- 
able reduction  in  quantity,  leads  to  the  inference  that  before  heat- 
ing the  acid  is  a  hydrate,  and  by  heating  parts  with  a  molecule  of 
water.  If  this  be  the  case,  the  difference  in  s.  g.  before  and  after  heat- 
ing would  be  accounted  for. 
These  data  show  conclusively  that  all  the  authorities  referred  to 
give  a  very  erroneous  s.  g.  for  oleic  acid,  excepting  Gmelin,  while  this, 
as  well  as  the  other  authorities,  quote  from  Chevreul ;  and  it  is  not  at 
all  strange  that  the  Pharmacopoeia  should  have  fallen  into  this  very 
popular  error.  It  seems  pretty  clear,  too,  how  the  error  occurred. 
Some  printer  or  copyist  has  probably  made  Chevreul's  *898  into  "808 ; 
not  a  difficult  thing  to  do,  especially  when  the  old  style  figure  9  is  used, 
as  it  may  have  been  seventy  years  ago.  It  is  rather  curious  that  no 
redetermination  of  this  s.  g.  has  reached  the  prominent  authorities 
referred  to,  since  doubtless  such  redeterminations  of  so  important  a  sub- 
stance must  have  been  often  made. 
The  Pharmacopoeia  is,  however,  wrong  in  its  temperatures  of  solidi- 
fication, since  by  these  it  permits  a  large  proportion  of  palmitic  acid  to 
be  present  in  the  oleic,  and  afterward  gives  a  hypercritical  test  for 
excluding  palmitic  acid  almost  entirely. 
Not  one  of  the  specimens  of  oleic  acid  made  for  this  investigation 
was  either  pale  yellow  in  color,  or  was  nearly  odorless  or  tasteless,  and 
the  after  taste,  in  the  fauces,  was  in  all  cases  very  pronounced. 
The  general  practical  conclusion  reached  here  is  that  for  medicinal 
uses  a  well  prepared  oleic  acid  from  red  oil  is  unexceptionable  and 
should  be  continued  in  use,  and  the  writer  will  still  continue  to  use  it, 
although  he,  with  all  others  who  do  use  it  now,  must  state  on  the  label 
that  it  is  not  the  oleic  acid  of  the  U.  S.  P.  of  1880.  Then  those  who 
can  get  an  acid  which  will  answer  the  officinal  tests  will  of  course  not 
take  this,  nor  be  liable  to  be  deceived  by  it. 
It  is  possible,  and  perhaps  even  probable,  that  oleic  acid  from  animal 
fats  is  better  for  use  in  the  animal  economy  than  one  from  vegetable 
fats,  for  the  same  reason  that  ointments  have  always  been  made  from 
animal  fats  rather  than  vegetable.  But  this  has  been  neither  proved 
nor  disproved.  It  is,  however,  a  more  important  question  now  than 
ever  before,  since  the  most  important  use  of  oleic  acid  now  is,  as  a 
vehicle  for  the  introduction  of  medicinal  agents  into  the  circulating 
