COMBINATION  OF  GLYCERINE  WITH  ACIDS. 
359 
that  is  necessary  to  separate  the  glycerine  is  the  precipitation  of 
the  ether  produced  by  water  (except  in  the  case  of  acetic  ether) 
and  the  evaporation  of  the  aqueous  fluid.  It  still  contains  a  little 
free  acid,  to  get  rid  of  which  it  is  agitated  with  a  little  oxide  of 
silver,  and  filtered  after  the  addition  of  water.  The  concentrated 
fluid  furnishes  pure  glycerine,  presenting  all  its  characters.  I  have 
reproduced  it  in  this  manner  with  each  of  the  combinations  formed 
with  benzoic,  valerianic,  acetic  and  sebacic  acids. 
The  acetic  compound  (acetine)  is  very  distinctly  soluble  in  water  ; 
it  possesses  an  agreeable  odor,  similar  to  that  of  acetic  ether,  but 
much  more  permanent-  Submitted  to  a  carefully-conducted  frac- 
tional distillation,  it  may  be  volatilized  without  sensible  decomposi- 
tion. After  this  operation,  it  preserves  its  pleasant  odor,  and  pre- 
sents the  appearance  of  a  limpid  and  colorless  oil,  possessing  a 
taste  which  at  first  is  saccharine  like  that  of  glycerine,  afterwards 
acrid  and  ethereal.  Treated  with  muriatic  acid  gas  and  alcohol,  it 
is  reduced,  as  before  distillation,  into  acetic  ether  and  glycerine. 
The  mixture  of  acetic  acid  and  glycerine,  saturated  at  212°  F.  with 
muriatic  acid  gas,  only  begins  to  furnish  this  substance  after  a 
week's  repose.  Several  natural  oils,  examined  by  M.  Chevreul 
and  others,  and  especially  cod-liver  oil,  yield  acetic  acid  on  saponi- 
fication ;  it  is  possible  that  acetine  may  form  one  of  the  principles 
of  these  oils. 
The  valerianic  compound  (valerine)  is  more  readily  obtained ; 
it  possesses  a  peculiar,  but  faint,  semi-ethereal,  semi-valerianic 
odor.  These  are  properties  possessed  by  the  phocenine  of  M. 
Chevreul,  one  of  the  principles  of  the  oils  of  the  dolphin,  which  is 
separable  into  phocenic  or  valeric  acid  and  glycerine.  The  quantity 
of  phocenine  in  these  oils  may  amount  to  a  fourth  or  a  third  of 
their  weight. 
The  benzoic  compound  (benzoicine)  is  formed  in  a  few  hours. 
It  is  more  viscous  than  the  two  preceding.  Its  taste  is  aromatic 
and  somewhat  like  pepper. 
The  sebacic  compound  (sebine)  is  formed  in  large  quantity  in 
twenty-four  hours.  It  is  an  example  of  a  neutral  compound  of  a 
bibasic  acid  and  glycerine. 
The  existence  of  these  substances  adds  support  to  the  facts  al- 
ready known,  in  showing  that  neutral  fatty  bodies  really  consist  of 
fatty  acids  and  glycerine. 
