AmKmeri£iarmi        Glycyrrhizin  in  Licorice  Root.  399 
I  have  found  a  different  way,  which  in  my  opinion  is  suitable  to 
determine,  fairly  accurately,  the  losses  in  glycyrrhizic  acid. 
I  evaporate  the  mother  liquor  and  wash  waters  to  a  syrup  after 
saturating  the  free  acid  with  ammonia.  I  transfer  this  saturated 
solution  of  ammonium  glycyrrhizinate,  and  ammonium  sulphate  or 
chloride,  to  a  narrow  glass  cylinder  graduated  in  y2  ccs.  The  solu- 
tion is  then  brought  to  such  a  volume,  that  for  every  gram  of  licorice 
extract  taken,  four  grams  of  solution  result.  I  then  precipitate  the 
glycyrrhizic  acid  with  sulphuric  acid,  of  which  for  every  gram  of 
acid  I  used  ten  drops.  After  standing  twelve  hours,  the  liquor  was 
filtered  through  a  fluted  filter,  5  cm.  diameter,  the  acid  was  collected 
on  the  filter  paper  and  washed  with  2  per  cent,  sulphuric  acid  at  2°  C. 
For  this  purpose  I  used  5  to  10  cc.,  according  to  the  quantity  of  the 
precipitate,  which  is  then  washed  with  5  to  10  cc.  of  water  saturated 
with  ether  at  20  C,  and  the  residue  is  dried  over  sulphuric  acid  in  a 
vacuum  desiccator.  The  filter  is  then  extracted  with  hot  95  per  cent, 
alcohol,  the  alcoholic  solution  is  evaporated,  and  the  residue  weighed 
as  glycyrrhizic  acid.  By  my  process  I  have  excluded  the  possibility  of 
decomposition.  Ammonium  glycyrrhizinate  is  so  stable  that  it  stands 
evaporation  even  to  dryness.  It  is  unfortunately  not  possible  to 
avoid  losses,  through  solubility  in  the  supernatant  liquid  from  the 
precipitation,  but  they  are  quite  small.  The  washing  of  the  glycyr- 
rhizic acid  also  causes  losses,  but  these  are  likewise  quite  small.  By 
following  the  above  experimental  procedure  I  believe  that  I  have  ob- 
tained practical  quantitative  results  which  are  interesting  in  showing 
the  losses  sustained  by  the  individual  methods. 
4.  The  Acid  Used  for  Precipitation. — Glycyrrhizic  acid  is  a 
weak  acid,  which  is  precipitated  by  most  other  acids.  For  the  quanti- 
tative determination  of  glycyrrhizin,  it  is  naturally  of  value  to  know 
which  acid  is  the  most  suitable  for  precipitation.  The  precipitants 
used  in  the  methods  to  be  investigated  are  sulphuric  acid,  hydro- 
chloric, and  absolute  alcohol.  I  made  comparative  investigations 
with  sulphuric,  hydrochloric,  boric,  oxalic,  tartaric,  phosphoric  and 
formic  acids.  I  made  such  a  solution  of  licorice  that  after  filtering, 
the  soluble  portion  of  the  licorice  was  present  in  the  proportion  1 : 9. 
Of  this  solution  10-gram  portions  were  treated,  in  wide  test  tubes,  with 
2.0  cc.  dilute  sulphuric  acid,  3.0  dilute  hydrochloric  acid,  5.0  phos- 
phoric, 15.0  hot  saturated  boric,  15.0  tartaric  (5  per  cent.),  3.0  nitric, 
10.0  formic.   The  contents  of  each  tube  was  made  up  to  25.0  cc.  By 
