SPONTANEOUS  SAPONIFICATION  OF  OILS  IN  SEEDS.  355 
by  the  action  of  sulphuric  acid  upon  colza-oil,  but  that  they  con- 
tain principally  double  acids,  and  that  they  cannot  furnish  fatty 
acids  without  at  the  same  time  eliminating  a  certain  quantity 
of  sulphuric  acid.  A  sample  of  one  of  these  residues,  sent  to 
me  from  Lille  by  M.  Kuhlmann,  was  entirely  soluble  in  cold 
water,  although  from  its  appearance  it  might  have  been  mistaken 
for  oil.  M.  Thenard,  who  is  the  founder  of  the  system  of  purifying 
lamp  oils,  now  become  one  of  the  principal  industries  of  the  north- 
ern departments,  observed  that  the  purification  does  not  take 
place  well  except  with  very  concentrated  sulphuric  acid  ;  this 
circumstance  is  now  explained  by  our  exact  knowledge  of  the 
nature  of  the  residue  of  the  purification. 
The  new  facts  contained  in  the  memoir  of  which  the  preceding 
is  an  abstract,  are  not  without  their  application.  Thus  linseed- 
meal  is  either  neutral  or  acid,  according  as  it  is  new  or  old,  and 
must  consequently  act  differently,  as  a  medicament.  That  which 
has  long  been  prepared  must  be  rejected,  even  though  it  may 
have  been  kept  in  well-closed  vessels.  I  have  several  times  found 
linseed-meal  in  the  shops,  in  which  all  the  oil  is  completely  acidi- 
fied. Milk  of  almonds,  freshly-prepared,  contains  neutral  oil  of 
almonds ;  by  the  following  day  acidification  has  already  com- 
menced. Any  edible  oil  will  have  a  different  composition  and 
taste,  according  to  the  length  of  time  that  has  elapsed  before  the 
seed  from  which  it  was  extracted  was  submitted  to  pressure.  The 
best  oils  for  the  table  are  those  which  have  been  extracted  im- 
mediately after  the  crushing  of  the  seed.  - 
Old  oil-cakes  may  be  advantageously  employed  in  the  manu- 
facture of  an  economical  soap.  All  that  is  necessary  is  to  mix 
them  with  an  alkaline  solution  ;  but  the  quantity  prepared  must 
be  small,  as  the  albuminoid  matter  contained  in  them  begins  to 
d<  compose  in  about  a  fortnight,  producing  a  very  disagreeable 
odor. — London  Chem.  Gaz.,  May  1st,  from  Comptes  Bendus, 
March  19,  1855,  p.  605.* 
f  The  important  bearing  which  many  of  the  facts  contained  in  this 
paper  have  on  various  preparations  and  processes  in  pharmacy,  renders  it 
worthy  of  a  careful  perusal  by  our  readers.  Many  anomalies  in  the  solu- 
bility of  the  fixed  oils  and  of  their  tendency  to  rancify,  may  be  cleared 
up.— Ed.  Am.  Journ.  Pharm.] 
