14 
Adum  Oleicum. 
Aiu  Jour.  Pharai. 
Jan.,  1884. 
distilled  in  a  current  of  superheated  steam,  it  becomes  a  pale  brownish 
yellow  oily  liquid,  transparent  at  summer  temperature,  but  at  15°  C 
=  59°  F.  it  deposits  about  half  its  volume  of  crystalline  white  palmitic 
or  margaric  acids  The  transparent  portion  separated  and  subjected 
to  a  temperature  of  about  10°C.=  50°  F.  deposits  an  additional  por- 
tion of  the  solid  acids.  These,  when  carefully  filtered  out  at  or  below 
this  temperature,  leave  the  oleic  acid  which  has  been  used  and  sold  by 
this  writer. 
It  is  a  pale  brownish  yellow,  oily  liquid,  varying  in  depth  of  color 
between  that  of  pale  and  ordinary  sherry  wine,  sometimes  as  deep  in 
color  as  almond  oil,  and  it  becomes  slightly  browner  by  age.  Thus 
far  it  practically  agrees  with  the  Pharmacopoeia  description.  But  it  is 
never  neutral  to  test  paper,  but  always  acid,  and  it  does  not  become 
rancid  and  acid  to  any  considerable  extent  by  any  ordinary  exposure. 
A  specimen,  exposed  to  the  air  in  a  shallow  basin  for  two  or  three 
weeks,  changed  very  little  in  sensible  properties,  and  in  its  action  on 
litmus  paper.  A  little  oxyoleic  acid  was  present  at  first,  and  probably 
increased  a  little,  but  1  cc.  of  10  pc.  solution  of  ammonia  in  50  c.c. 
of  water,  shaken  with  50  cc.  of  the  oleic  acid,  deprived  it  of  its  acid 
reaction,  both  in  that  portion  which  had  been  exposed  and  that  which 
had  not.  Therefore,  the  proportion  of  oxyoleic  acid  must  be  so  small 
as  to  be  insignificant,  and  yet  is  sufficient  to  give  an  acid  reaction 
always. 
This  oleic  acid  is  not  "  odorless  or  nearly  so,"  but  has  a  peculiar,  dis- 
tinct odor  that  is  not  that  of  rancid  fat,  but  is  suggestive  of  that  odor, 
though  it  is  not  disagreeable  to  most  persons,  and  the  taste  is  like  the 
odor,  but  it  is  not  the  acrid,  almost  pepper-like  taste  of  rancid  oils, 
though  it  gives  a  distinct  after  taste  of  acridity  in  the  fauces.  The 
s.g.  compared  with  water  at  4°  C.  is  not  "0*800  to  0*810,"  but  is 
•8955  at  15°  C.  =  59°  F.,  and  '8896  at  25°C.=  77°  F.  It  is  com- 
pletely soluble  in  alcohol,  but  the  other  solubilities  stated  were  not 
tried.  "At  14°  C.  (57-2°  F.)"  it  does  not  become  semi-solid,  but 
remains  transparent  at  4°  to  5°C.  It  may  not  be  of  any  great  dis- 
advantage to  the  oleic  acid  for  medicinal  uses,  to  leave  in  it  the  very 
considerable  amount  of  palmitic,  margaric  or  other  acids  of  higher 
melting  points  permitted  by  this  test,  but  the  test  simply  rules  out  an 
oleic  acid  which  has  less  of  these  other  acids  in  it.  The  small  pro- 
portion of  oxyoleic  acid  doubtless  lowers  the  solidifying  point  of  all 
the  fatty  acids,  but  not  to  a  very  great  extent.    The  oxyoleic  acid  is 
