458  Glycyrrhizin  in  Licorice  Root.        j  Amjjfyri^iarm' 
termined  the  loss  on  4  g.  licorice.  It  corresponded  to  1. 0-1.25  per 
cent,  of  the  licorice.  The  matter  insoluble  in  the  alcohol-water  mix- 
ture was  50  per  cent.  In  examining  the  method  and  the  results  I  ob- 
tained with  it,  I  found  there  are  no  serious  objections  to  be  made  to 
it,  and  that  it  gives  practical  results. 
11.  Tschirch-Erikson  (ipio). 
"Ten  g.  licorice  extract  are  dissolved  in  a  100  g.  cold  water,  100 
cc.  of  90  per  cent,  alcohol  are  added  with  stirring,  and  the  mixture 
warmed  on  the  water  bath  for  half  an. hour.  It  is  then  filtered,  and 
washed  with  50  cc.  hot  alcohol.  The  alcohol  is  removed  from  the 
filtrate  on  the  water  bath,  and  the  volume  made  up  to  200  cc.  with 
distilled  water  in  a  volumetric  flask. 
Glycyrrhizin :  40  cc.  of  this  solution  are  taken  out  with  a  pipette, 
and  25  per  cent,  sulphuric  acid  is  added  as  long  as  a  precipitate 
forms.  After  standing  two  to  three  hours  it  is  filtered  through  a  small 
filter,  and  washed  with  5  per  cent,  sulphuric.  The  filter  with  the 
residue  is  heated  for  a  quarter  of  an  hour  on  a  water  bath,  in  a  small 
porcelain  dish,  with  50  cc.  90  per  cent,  alcohol.  It  is  then  filtered 
and  30  cc.  water  added.  After  driving  off  the  alcohol,  another  30  cc. 
of  water  and  then  25  per  cent,  sulphuric  acid  are  added  until  the 
glycyrrhizin  is  precipitated.  After  standing  for  one  hour,  the  liquid 
is  filtered  through  a  small  filter,  and  the  latter  treated  with  5  per 
cent,  cold  alkali.  After  solution  has  occurred,  it  is  filtered  at  once 
into  a  potash-glass  flask,  fitted  with  a  reflux  tube,  and  the  filter  is 
washed  out  with  100  cc.  water.  120  cc.  Fehling  solution  are  then 
added  and  boiled  for  15  hours.  The  precipitated  Cu20  is  deter- 
mined according  to  Allihn,  and  the  glucose  number  found  is  calcu- 
lated to  glycyrrhizic  acid  according  to  the  equation : 
360  :  896  =  quantity  of  glucose  :  X." 
The  method  of  Tschirch-Erikson  is  of  great  significance.  It 
points  out  an  entirely  new  way  to  a  complete  assay  of  licorice  root 
and  extract.  In  checking  up  this  method  I  shall  not  adhere  strictly 
to  the  title  of  my  subject,  but  shall  also  examine  Erikson's  proposal 
for  the  determination  of  sugars.  I  believe  this  is  all  the  more  neces- 
sary, since  as  can  be  easily  seen,  the  determination  of  sugars  is  diffi- 
cult to  separate  from  that  of  glycyrrhizin  in  this  method  for  licorice 
