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ARTIFICIAL  FORMATION  OF  TARTARIC  ACID. 
lichen  agrius  as  an  external  application,  also  to  the  excoriations 
from  eczema.  It  should  be  applied  with  a  camel's  hair  brush. — 
London  Pharm.  Journ.  Dec.  1859. 
ON  THE  ARTIFICIAL  FORMATION  OF  TARTARIC  ACID. 
By  Professor  Liebig. 
Professor  Liebig  has  lately  made  the  very  interesting  obser- 
vation that  tartaric  acid  is  among  the  products  of  decomposition 
of  sugar  of  milk  by  nitric  acid.  On  examining  the  acid  mother 
liquid,  after  the  separation  of  mucic  acid,  he  found  among  other 
constituents  an  organic  acid,  some  of  the  salts  of  which,  when 
analyzed,  yielded  results  differing  materially  from  the  salts  of 
the  same  bases  with  mucic  acid,  but  agreed  with  the  composition 
of  the  corresponding  tartrates.  A  comparison  between  the 
latter  and  the  salts  obtained  from  the  mother  liquor,  and  the 
further  examination  of  the  isolated  acid,  proved  the  identity  of 
this  acid  with  tartaric  acid.  But  besides  the  true  tartaric  acid, 
the  mother  liquor  appears  to  contain  another  acid  of  the  same 
composition,  but  somewhat  different  properties,  probably  a 
modification  of  tartaric  acid.  Professor  Liebig  is  still  occupied 
with  the  researches  on  this  subject,  and  expects  to  be  able  soon 
to  report  his  results. 
To  this  preliminary  notice  it  must  be  added  that  Professor 
Liebig  tested  the  sugar  of  milk  which  he  used,  for  tartaric  acid, 
so  as  to  remove  all  suspicion  of  the  sugar  having  been  accident- 
ally contaminated  with  the  acid. 
This  discovery  of  Liebig's  is  very  interesting,  as  it  appears  to 
be  the  first  observation  of  the  artificial  formation  of  tartaric 
acid.  Professor  Erdmann  of  Leipzig,  in  1836,  while  studying 
the  products  of  decomposition  of  sugar  by  nitric  acid,  for  the 
purpose  of  investigating  Guerin's  hydroxalic  acid,  obtained  an 
acid  which,  in  accordance  with  his  analyses,  he  took  to  be  a 
modification  of  tartaric  (metatartaric)  acid,  and  which,  as  he  ob- 
served, was  spontaneously  converted  into  tartaric  acid.  (Anna- 
len  d.  Pharm.  xxxvi.  1.)  Subsequently,  however,  on  investigating 
the  same  subject,  H.  Hess,  of  St.  Petersburg,  came  to  a  differ- 
ent result,  and  declared  Erdmann's  metatartaric  acid  to  be 
