Amjui°y  ri92farm' \        Glycyrrhizin  in  Licorice  Root.  459 
extract,  and  in  the  case  of  root,  cannot  be  separated  from  it  at  all. 
If  I  take  a  long  time  over  this  work,  this  is  done  because  at  the  time 
it  was  published,  it  was  taken  up  in  all  the  journals,  including  the 
foreign  ones,  .and  was  praised  by  them.  Further,  a  detailed  control 
of  the  method  does  not  appear  to  have  been  attempted  by  them.  But 
above  all,  because  the  name  of  the  author  appears  to  guarantee  that 
Tschirch's  method  could  perhaps  be  accepted  without  such  a  control. 
The  hydrolysis  of  glycyrrhizic  acid  appears  to  have  been  finally  ex- 
plained and  established  by  formulas  by  Tschirch  and  his  pupils.1  By 
the  hydrolysis  with  acids  or  alkalis,  there  is  formed  from  glycyr- 
rhizic acid,  glycyrrhetic  acid  and  glucuronic  acid. 
I  here  quote  Erikson  word  for  word,  "As  an  aldehyde,  glucu- 
ronic acid  reduces  Fehling  solution,  and  if  it  is  possible  to  decom- 
pose glycyrrhizic  acid  quantitatively  into  its  components,  a  process 
based  on  this  reduction  must  lead  easily  to  a  quantitative  determina- 
tion." "On  the  reducing  capacity  of  the  glucuronic  acid,  split  of! 
by  hydrolysis,  Tschirch  has  based  his  method  for  the  determination 
of  glycyrrhizin.  And  since  both  glucose  and  saccharose  also  reduce 
Fehling  solution,  but  under  different  conditions,  so  must  the  three 
most  important  ingredients  of  licorice  root  (and  Erikson  also  arrived 
at  this  conclusion),  be  capable  of  quantitative  determination  through 
their  behavior  towards  this  reagent." 
The  method  stands  or  falls  by  the  answer  to  the  question :  Can 
glycyrrhizic  acid  be  determined  quantitatively  by  hydrolysis  by 
means  of  Fehling  solution?  Unfortunately  I  must  definitely  answer 
this  question  in  the  negative.  Although  the  proof  of  this  statement 
would  prove  the  inadequacy  of  the  method,  I  wish  to  enter  into  the 
whole  procedure  of  the  method,  because  it  contains,  both  theoretically 
and  practically,  a  good  deaLwhich  is  open  to  controversy. 
[Translator's  Note. — Linz  then  proceeds  to  the  fact  that  an 
exact  quantity  of  sulphuric  acid  is  not  specified,  particularly  in  wash- 
ing with  5  per  cent,  sulphuric  acid.  He  found  that  heating  the  alco- 
hol-sulphuric acid  solution  for  a  quarter  of  an  hour  carbonized  the 
solution,  and  mentions  a  whole  series  of  other  manipulative  difficul- 
ties. He  thinks  an  actual  oversight  occurs  at  one  place  in  Tschirch's 
method,  and  that  Tschirch  intends  potash  to  be  used,  but  omits  to  say 
1  Archiv  d.  Pharm.,  245,  97;  246,  545. 
