392  Glycyrrhizin  in  Licorice  Root.        j Am)lTJ,'m\*rm' 
of  glycyrrhizin  can,  in  general,  occur.  Under  these  circumstances,  it 
is  remarkable  that  since  Diehl,  and  also  quite  recently,  methods  have 
been  published  which  use  no  alcohol.  The  latter  are,  without  doubt, 
inferior  to  those  using  alcohol. 
Rump  in  1855  appears  to  have  been  the  first  to  propose  an  am- 
moniacal  solvent  for  licorice  extract.  As  I  already  mentioned  in  the 
introduction,  he  deduced,  from  the  fact  that  the  matters  insoluble  in 
cold  water  yielded  a  certain  amount  to  ammonia,  that  there  was 
present  a  glycyrrhizin  soluble  in  water,  and  one  soluble  only,  in  am- 
monia. Schroeder  also,  in  1883,  emphasizes  the  difference  between 
soluble  and  insoluble  glycyrrhizin.  I  consider  this  ammoniacal  ex- 
traction not  the  correct  method. 
In  the  introduction,  I  have  mentioned  that  Tschirch  considers 
the  ''glycyrrhizin"  of  the  root  present  as  a  potassium'  and  calcium 
salt  of  glycyrrhizic  acid.  He  arrived  at  this  view  on  the  basis  of  the 
following  experiment:  A  saturated  aqueous  infusion  of  the  root 
was  treated  with  an  equal  volume  of  alcohol,  filtered,  and  to  the  fil- 
trate three  times  the  volume  of  absolute  alcohol  added.  The  glycyr- 
rhizin compounds  were  thus  precipitated.  The  precipitate  was 
filtered  off,  dissolved  in  glacial  acetic  acid,  and  purified  by  crystal- 
lization. Tschirch  obtained  two  kinds  of  crystals,  which  showed  by 
qualitative  analysis,  the  presence  of  potassium  and  calcium. 
The  statement  of  Fliickiger  in  1867,  that  "glycyrrhizin"  is  the 
ammonium  salt  of  the  acid,  has  been  doubted  by  many,  among  them 
Sestini.  Tschirch  considerd  that  he  has  definitely  disproved  this 
view,  since  in  the  precipitate  mentioned  above,  he  found  no  ammo- 
nium compound.  The  opinion  which  has  been  published  in  one 
paper,  that  the  magnesium  salt  of  the  acid  is  concerned,  is  in  itself 
not  improbable.  It  has,  up  to  the  present,  not  been  contradicted.  In 
addition  to  the  combined  acid,  the  root  is  said  to  contain,  according 
to  statements  in  the  literature  which  agree  on  this  point,  also  small 
quantities  of  free  glycyrrhizic  acid. 
In  the  preparation  of  licorice  extract,  which  is,  in  part,  still  very 
primitive  (see  Tschirch's  "Handbook"  and  Anselmino-Gilg  "Com- 
mentary"), the  root  is  boiled  with  water.  The  small  quantities  of 
the  free  acid  are  certainly  neutralized  by  the  constituents  of  the  well- 
water,  or  by  salts  of  the  root,  so  that  it  may  be  taken  as  established, 
that  glycyrrhizic  acid  occurs  in  licorice  extract  only  in  combined 
form.   Without  wishing  to  decide  the  question  of  what  compounds 
