ON  RACEMIC  ACID. 
251 
from  tartaric  acid,  and  which  he  took  to  be  racemic  acid.  In  a 
letter  to  M.  Pelouze,  Mr.  White  stated  also  that  the  tartars  he  had 
been  in  the  habit  of  employing  were  imported  from  Naples,  Sicily, 
and  Oporto.  M.  Kestner,  when  informed  of  this  circumstance  by 
M.  Pelouze,  remembered  that  he  had  also  used  some  tartars,  the 
produce  of  Italy,  at  the  time  of  his  obtaining  racemic  acid.  About 
the  same  time,  also,  it  was  found  that  large  quantities  of  racemic 
acid  were  met  with  in  commerce  in  England,  although  this  product 
was  quite  unknown  in  the  English  manufactories  of  tartaric  acid. 
On  investigating  the  subject,  it  was  found  that  this  racemic  acid 
came  from  some  German  manufacturers. 
About  the  month  of  August  last,  M.  Mitscherlich  apprised  M. 
Pasteur  that  M.  Fikentscher,  a  skilful  manufacturer  in  Saxony, 
prepared  racemic  acid,  and  had  supplied  him  with  some.  In  con- 
sequence of  this  information,  M.  Pasteur  went  to  M.  Fikentscher's 
manufactory,  and  learned  from  him  that  this  acid  was  regularly 
produced  in  his  manufactory,  but  that  the  quantity  obtained  had 
very  much  fallen  ofF  since  his  employment  of  tartars  imported  from 
Trieste.  In  fact,  since  M.  Pasteur's  visit,  the  quantity  produced 
was  so  small  as  at  last  to  be  quite  lost  sight  of  altogether.  In 
operating  on  Neapolitan  tartars,  the  needle-shaped  crystals  of 
racemic  acid  were  scarcely  discernible,  on  account  of  the  smallness 
of  their  quantity,  amidst  the  large  masses  of  tartaric  acid  contained 
in  the  crystallizing  vessels.  In  addition,  these  small  crystals  of 
racemic  acid  did  not  make  their  appearance  in  the  first  crops  of 
crystals,  and  but  in  small  quantities  in  subsequent  crystallizations; 
whence  we  see  that  this  acid  is  but  extremely  little  soluble  in  a 
concentrated  solution  of  tartaric  acid. 
Knowing  that  M.  Kestner  formerly  obtained  racemic  acid  in  such 
quantities  as  to  be  able  to  sell  it  by  the  hundred-weight,  M.  Pas- 
teur was  much  surprised  at  the  smallness  of  the  quantity  produced 
at  M.  Fikentscher's  manufactory;  it  struck  him,  however,  that  the 
difference  might  be  accounted  for  in  the  circumstance,  that  whilst 
M.  Kestner  employed  the  rough,  unrefined  tartars,  M.  Fikentscher 
used  those  which  had  been  partially  refined,  and  it  appeared  clear 
to  M.  Pasteur,  that  if  racemic  acid  existed  ready  formed  in  the 
tartars,  the  principal  portion  of  it  would  be  remaining  in  the 
mother  liquors  of  the  refinery,  whatever  might  be  its  condition  in 
