Am.  Jour.  Pharm. 
Jan.,  1884. 
Acidum  Oleicum. 
15 
also  objectionable,  therapeutically,  because  it  is  an  irritant,  and  there- 
fore there  should  be  a  limit  set  to  the  amount  which  is  permissible. 
The  test  given  for  the  absence  of  more  than  traces  of  palmitic  and 
stearic  acid  will  never  be  satisfied  by  any  oleic  acid  which  the  writer 
has  ever  seen  which  becomes  semi-solid  at  14°  C.  =  57  2°F.,  since  all 
the  solid  portions  at  this  temperature  are  margaric  or  palmitic  acids. 
Another  point  which  invalidates  this  test  is  that  a  soap  made  with  a 
carbonated  alkali  as  directed,  without  boiling,  will  always  give  a  pre- 
cipitate with  acetate  of  lead,  which  will  contain  carbonate  of  lead,  and 
this  of  course  not  being  soluble  in  ether,  would  be  accepted  as  palmi- 
tate  or  stearate  of  lead,  when  neither  the  one  nor  the  other  was 
present. 
The  principal  differences  between  the  oleic  acid  which  has  hitherto 
been  used  and  that  now  required  by  the  Pharmacopoeia  are,  the  odor, 
taste,  acidity,  specific  gravity,  and  solidifying  point.  And  the  greatest 
of  these  differences  is  in  specific  gravity.  All  the  others  may  be 
understood  as  being  differences  between  a  chemically  pure  acid  and 
one  that  is  less  pure,  and  the  question  would  be  whether  a  chemically 
pure  substance  was  needed  for  these  external  uses,  after  all  the  expe- 
rience made  with  the  oleates  has  been  from  an  acid  which,  though  of 
good  quality,  is  not  chemically  pure.  But  the  very  great  difference  in 
specific  gravity  must  mean  more  than  this,  and  it  led  the  writer  to 
make  the  following  investigations : 
On  referring  to  authorities,  it  was  found  that  Gmelin  quotes  Chevreul 
as  his  authority,  and  gives  '898  at  19°  C.  Watt's  Dictionary  of  Chem- 
istry also  quotes  Chevreul,  but  gives  *808  at  19°  C.  In  Wurtz  Dic- 
tionnaire  de  Chimic,  the  article  on  oleic  acid  is  written  by  P.  Schutzen- 
berger,  and  gives  *808  at  19°  C.  Other  authorities  seem  to  copy  almost 
exclusively  the  latter  figures,  and  the  temperature  being  the  same,  it 
seems  probable  that  all  come  down  from  Chevreul  who  wrote  seventy 
years  ago,  and  that  some  one  has  made  a  mistake.  Allen,  however, 
gives  *900  to  *905  for  commercial  oleic  acid. 
A  specimen  bottle  of  German  oleic  acid,  from  a  very  good  maker, 
costing,  wholesale,  $11  per  pound,  not  labelled  "  C.  P.,  was  carefully 
examined  in  comparison  with  the  above-mentioned  acid  from  red  oil. 
It  was  of  the  color  of  pale  sherry — not  lighter  than  the  best  specimens 
from  red  oil — had  the  same  peculiar  odor  and  the  same  acid  reaction. 
The  s.  g.  under  the  same  conditions  of  standard  and  temperature  was 
•8923  at  15°  C.  =  59°F.  and  -8864  at  25°  C.  =  77°F.;  and  it 
