404  Glycyrrhizin  in  Licorice  Root \        ^  AmjuSeri^arm* 
more  than  0.5  to  0.6  per  cent.  In  spite  of  the  greatest  care,  and 
keeping  experimental  conditions  as  nearly  alike  as  possible,  it  was 
difficult  to  obtain  values  which  agreed  well  Many  other  investi- 
gators with  glycyrrhizin  have  made  the  same  observation.  All  weigh- 
ings were  made  on  a  chemical  balance  to  within  one-half  mg.  Liquids 
were  evaporated  on  the  water  bath.  Drying  to  constant  weight  took 
place  in  a  water  oven  which  always  showed  980  C.  I  also  used  this 
oven  when  the  directions  called  specifically  for  ioo°,  being  convinced 
that  the  difference  of  20  was  of  less  importance  than  the  advantage 
of  always  having  a  uniform  temperature. 
SUMMARY  OF  THE  PUBLISHED  METHODS  FOR  GLYCYRRHIZIN 
DETERMINATION. 
A.  Extraction  liquid :  Water  without  the  use  of  alcohol. 
Precipitation  with  sulphuric  acid:  (1)  Rump,  (2)  Helfen- 
berger,  (3)  Capin. 
Precipitation  with  hydrochloric:  (4)  French  Pharmaco- 
poeia. 
B.  Extraction  liquid:  Water  with  addition  of  alcohol. 
Precipitation  with  sulphuric  acid:  (5)  Diehl,  (6)  Kremel, 
(7)  Py,  (8)  Parry,  (9)  Evans'  Sons,  Lesher  &  Webb, 
(10)  Houseman,  (11)  Erikson,  (12)  Guignard. 
Precipitation  with  hydrochloric:  (13)  Gadais  I,  (14)  Ga- 
dais  II. 
Precipitation  with  absolute  alcohol:  (15)  Trubeck. 
C.  Extraction  liquid :  Ammoniacal  water  without  addition  of  al- 
cohol. 
Precipitation  with  sulphuric  acid:  (16)  Schroder,  (17) 
Miintzer,  (18)  Morpurpo. 
Precipitation  with  hydrochloric:  (19)  Dutch  Pharmaco- 
poeia. 
D.  Extraction  liquid :  Ammoniacal  water  with  addition  of  alco- 
hol. 
Precipitation  with  sulphuric  acid :  (20)  Kinzey,  (21)  Ansel- 
mino-Gilg. 
Precipitation  with  hydrochloric:  (>22)  Stoeder,  (23)  Telle, 
(24)  Durier. 
E.  Extraction  liquid :  Alcohol-sulphuric  acid. 
Precipitation  with  sulphuric  acid:  (25)  Haffner,  (26)  Ce- 
derberg,  (27)  Schmidt  (Haffner). 
The  control  experiments  which  now  follow  are  arranged  in  the 
order  of  this  table. 
