Amjune,ri£iarm'}        Glycyrrhizin  in  Licorice  Root.  405 
1.  Rump  (18 j 5). 
''One  part  of  licorice  extract  is  dissolved  in  three  parts  of 
water.  Half  an  ounce  of  the  solution  is  diluted  with  one  ounce  of 
water,  and  one  drachm  of  dilute  sulphuric  added.  The  washed  and 
dried  precipitate  should  amount  to  between  live  and  seven  grains." 
Converted  to  our  present  system  of  weights,  Rump  would  re- 
quire that  from  a  solution  of  3.75  g.  of  licorice  in  45  g.  water,  0.3  to 
0.42  g.  glycvrrhizic  acid  should  be  separated  by  3.75  g.  dilute  sul- 
phuric acid.  He  therefore  requires  8  to  11.2  per  cent,  a  content 
which  indeed  corresponds  approximately  to  present-day  require- 
ments. This  method  of  Rump  has,  of  course,  only  historical  inter- 
est, as  the  first  published  glycyrrhizin  estimation.  I  therefore  did 
not  attempt  to  check  it  up. 
2.  Helfenbcrgcr  Annalen  (i<?p7). 
"Five  grams  licorice  extract  are  dissolved  in  50  g.  water,  filtered, 
the  filter  washed  with  water,  and  5  cc.  dilute  sulphuric  acid  added  to 
the  nitrate.  The  precipitate  is  collected  on  a  small  filter,  washed 
well,  dissolved  in  ammonia,  filtered,  the  filtrate  evaporated  in  a 
weighed  dish,  and  the  residue  dried  at  iocr  to  constant  weight." 
A  solution  of  5  g.  licorice  in  50  g.  water  filters  with  great  diffi- 
culty. I  required  in  one  case,  eight  hours  to  filter  and  wash  that 
quantity  until  nearly  colorless.  The  method  in  its  description  is  so 
vague  that  one  can  obtain  results  which  agree  only  when  one  com- 
pletes the  missing  instructions.  He  says,  "Filter,  wash  with  water, 
and  wash  the  precipitate  thoroughly."  These  instructions,-  on  ac- 
count of  their  inexactness,  must  give  large  differences  in  the  values 
obtained.  To  wash  the  insoluble  residue,  I  used  50  cc.  of  water 
which,  however,  was  not  enough  to  obtain  a  completely  colorless  fil- 
trate. To  wash  out  the  acid  I  used  30  cc.  in  small  quantities.  Drop- 
ping ammonia  on  the  filter  paper  holding  the  acid,  was  not  practical, 
as  the  liquid  filters  with  great  difficulty.  As  the  instructions  may 
also  be  interpreted  I  hare  dissolved  the  acid  on  the  filter  paper  in 
warm  ammonia,  filtered,  and  washed  the  filter  paper  until  color- 
less. From  several  experiments,  I  obtained  between  6.9  per  cent, 
and  7.2  per  cent,  yield,  weighing  0.344,  0.348,  0.357,  0.360,  0.365  g. 
ammoniated  glycyrrhizin  from  5  g.  licorice.  From  the  method  given 
in  the  introduction,  I  obtained  as  the  loss  from  the  5  g.  licorice  0.18- 
°-I9   g-    glycvrrhizic    acid,    corresponding   to    3.6-3.8   per  cent. 
