Am.  Jour.  Pharm. 
June,  1921. 
Glycyrrhizin  in  Licorice  Root. 
407 
the  greater  solubility  in  the  increased  quantity  of  water.  The  super- 
natant liquid  is  poured  off  from  the  acid,  and  the  latter  washed  free 
from  sulphuric  acid  by  decantation  with  water  at  o°.  The  quantity 
of  water  to  be  thus  used  is  not  stated.    From  2  g.  licorice,  I  weighed 
0.  140,  0.1 5 1,  0.156,  0.160  g.  ammonium  glycyrrhizinate,  that  is  7-8 
per  cent.  This  amount  would  be  increased  to  12. 7-13. 5  per  cent,  by 
the  improvements  mentioned  below. 
These  values  are  too  low,  more  particularly  because  of  the 
losses  from  the  solution  remaining  on  the  filter.  I  found  the  loss 
from  4  g.  of  licorice  to  be  0.051  and  0.061  g.  of  glycyrrhizic  acid, 
1.  e.,  1. 25-1. 53  per  cent.  On  the  filter  there  remained  32  per  cent,  of 
insoluble  matter.  It  can  be  seen  from  the  above  that  this  method 
has  been  badly  worked  out,  and  the  necessary  directions  for  obtain- 
ing accurate  results  are  missing.  This  method  can  therefore  give 
only  unsatisfactory  results.  No  purification  is  prescribed,  and  Capin 
does  not  use  alcohol  in  spite  of  the  great  advantages  obtainable 
thereby.  The  ammonium  salt  weighed  is  therefore  very  impure. 
Capin  makes  the  very  interesting  experiment  of  decreasing  the  solu- 
bility error  by  adding  a  factor,  good  for  every  case,  to  the  value  ob- 
tained. In  the  introduction  I  have  already  pointed  out  that  Capin 
obtained  this  solubility  factor  by  shaking  up  an  excess  of  glycyrrhizic 
acid  with  water  and  estimating  the  soluble  part  at  15°  and  o°.  He 
calculates  the  factor  for  20  cc.  of  liquid  precipitated  and  so  obtained 
the  number  0.110  to  be  added  to  the  value  found  for  ammoniated 
glycyrrhizin.  This  improvement  is  wholly  undemonstrated  and 
lacks  any  real  basis.  The  following  objection  applies  to  it :  The  solu- 
tions used  in  glycyrrhizin  determinations  are  never  saturated,  but 
are  always  quite  weak.  This  is  particularly  the  case  with  those 
solvations  which  are  to  be  corrected  for  losses  through  washing. 
[Translator's  Note. — Here  follows  a  half  page  more  of  fur- 
ther objections  to  Capin's  method.  (P.  A.  H.)] 
4.  French  Pharmacopoeia  (1908). 
"Two  g.  licorice  are  taken  up  in  aqueous  solution,  filtered,  made 
to  100  cc.  and  30  drops  of  hydrochloric  acid  are  added.  After  stand- 
ing 24  hours,  the  liquid  is  poured  through  a  filter,  the  residue  and 
filter  washed  three  times  with  8  cc.  portions  of  water,  and  then  10-15 
cc.  water,  containing  5  drops  of  ammonia  per  10  cc.  is  poured  through 
this  filter.  The  filter  is  washed  with  distilled  water,  and  the  solution  of 
