472 
Glycyrrhizin  in  Licorice  Root. 
5  Am.  Jour.  Pharm. 
\      July,  1921. 
It  is  true  that  none  of  these  methods  attempt  to  achieve  a  high 
degree  of  purity  of  the  glycyrrhizic  acid  weighed.  Particularly  in 
the  case  of  Parry  and  Evans'  Sons,  is  little  attention  given  to  the 
washing  of  the  glycyrrhizic  acid. 
According  to  my  experience  "with  the  individual  methods,  none 
of  them  completely  fulfills  the  requirements  which  are  demanded.  One 
must,  of  course,  leave  out  of  account  small  errors  which  are  un- 
avoidable in  a  glycyrrhizin  determination. 
Experiments  to  Work  Out  a  Glycyrrhizin  Determination. 
In  the  hope  of  obtaining  a  purer  form  of  glycyrrhizic  acid,  I 
have  treated  the  precipitated,  impure  acid  with  all  the  organic  sol- 
vents available  to  me.  All  such  attempts,  including  those  with  salts 
of  glycyrrhizin,  proved  to  be  quite  impracticable.  The  converse 
method  of  retaining  the  acid  and  dissolving  the  impurities  in  a  sol- 
vent, did  not  work  out.  I  further  attempted  to  find  a  glycyrrhizin 
salt,  more  particularly  of  a  metal,  which  I  could  purify,  and  then 
decompose  again,  perhaps  with  hydrogen  sulphide.  These  attempts 
were  also  unsuccessful. 
The  copper  salt,  of  a  fine  green  color,  seemed  to  promise  suc- 
cess, but  after  being  thoroughly  washed,  and  decomposed  with 
hydrogen  sulphide,  a  glycyrrhizin  was  obtained  which  was  just  as 
dirty  and  unattractive  as  before.  It  seems  therefore  that  the  impuri- 
ties are  themselves  acid  in  character,  and  are  in  every  case  attached 
to  the  metal. 
All  these  experiments,  which  consumed  much  time,  proved  to  be 
impractical.  It  therefore  seems  as  though  one  can  only  proceed 
along  the  lines  already  laid  down.  I  believe  that  the  object  is  best 
obtained  if  one  starts  out  from  the  method  of  Diehl. 
The  method  which  I  would  here  propose,  is  of  course  not  exact. 
I  have  often  emphasized,  that  in  my  opinion,  accuracy  is  not  to  be 
achieved.  It  gives  good  results,  however,  inasmuch  as  it  corrects 
some  of  Diehl's  mistakes,  and  makes  use  of  the  experience,  which  has 
meanwhile  been  gained.  Above  all  it  previously  purifies  the  glycyr- 
rhizic acid  weighed. 
My  Own  Method. 
Five  g.  licorice  are  treated  with  50  g.  distilled  water  with  fre- 
quent shaking  and  slight  warming,  until  disintegrated,  and  after 
cooling,  100  cc.  95  per  cent,  alcohol  are  added.    After  standing  six 
