ON  LACTIC  ACID. 
423 
On  the  average  of  two  concordant  analyses,  the  oil  consisted 
of— 
C  79-60  13  79-59 
H  12-31  12  12-24 
0       8-09  1  8-17 
If  we  suppose  that  most  of  the  oxygenated  oils  also  contain 
an  oil  free  from  oxygen  of  the  formula  C5  H4,  the  oxygenated 
oil  would  have  the  formula  C8  H8  0,  add  to  which  that  of  the  oil 
free  from  oxygen,  C5  H4 
=  Ci3  Hi2  a 
Lond.  Chem.  Gfaz.,  May  15,  1858,  from  Archiv.  der  Pharm. 
ON  LACTIC  ACID. 
By  A.  Bruning. 
The  author's  object  was  to  decide  whether  lactic  acid  written 
C12  H12  O12  saturates  4  equivs.  of  base,  or  regarded  as  C6  H6  O6, 
saturates  2  equivs.  of  base. 
The  lactic  acid  employed  in  the  experiments  was  prepared  by 
Bensch's  process.  From  this  the  author  always  first  prepared 
the  zinc-salt,  which  was  purified  by  recrystallization.  For  the 
solution  of  his  problem  he  selected  the  following  salts. 
Protolactate  of  tin,  prepared  by  mixing  a  solution  of  lactate 
of  soda  with  one  of  protochloride  of  tin,  has  the  composition 
012  H8  08+4SnO,  not  as  stated  by  Engelhardt  and  Maddrell? 
C12  H10  O104-4SnO.  Consequently  4  equivs.  of  hydrogen  are 
actually  displaced  by  SnO  in  the  lactic  acid. 
With  peroxide  of  mercury  the  author  did  not  obtain  a  tetra- 
basic  salt.  When  he  saturated  dilute  boiling  lactic  acid  with 
peroxide  of  mercury  in  accordance  with  the  directions  of  Engle- 
hardt  and  Maddrell,  he  observed  a  strong  evolution  of  gas  and 
and  an  odor  of  aldehyde.  The  salt  which  separated  by  crystal- 
lization was  a  protosalt.  This  does  not  agree  with  the  salt 
described  by  Englehardt  and  Maddrell  as  the  protosalt,  but  with 
the  colorless  salt,  regarded  as  a  persalt  by  those  chemists. 
This  salt  is  white,  is  not  decomposed  by  boiling  water,  and  loses 
no  water  at  212°  F.  Its  analysis  led  to  the  formula  of  the 
bibasic  protosalt,  C12  H10  Hg4  O12. 
