Am.  jour.  Pharm.)        Glycyrrhizin  in  Licorice  Root .  413 
June,  1921.        >  J  J 
9.  Evans'  Sons,  Lesher  &  Webb  (1910). 
"2.5  g.  of  finely  pondered  material  are  weighed  into  a  little 
beaker,  15  cc.  water  added,  and  warmed  on  the  water  bath  to  dis- 
solve. After  cooling,  23  cc.  technical  alcohol  mixed  with  2  cc.  water, 
are  added  with  stirring,  and  then  50  cc.  alcohol.  After  standing  for 
half  an  hour,  the  liquid  is  filtered  into  an  evaporating  dish  and  the 
precipitate  is  washed  with  a  mixture  of  50  cc.  of  technical  alcohol 
with  4  cc.  water.  The  filtrate  and  washings  are  evaporated  to  a 
syrup  on  the  water  bath,  transferred  to  a  thin-walled  glass  cylinder 
with  30  cc.  water,  cooled  in  melting  ice  and  mixed  with  3  cc.  sul- 
phuric acid  (1-30).  The  contents  of  the  cylinder  are  brought  to 
freezing  in  an  ice-salt  mixture,  and  the  glycyrrhizin  is  obtained  as  a 
solid  mass  on  the  bottom  of  the  cylinder  by  allowing  to  thaw  slowly. 
It  is  washed  by  decantation  with  50  cc.  water  ato°,and  as  much  of  the 
liquid  decanted  as  possible.  Two  cc.  ammonia  water  are  then  added, 
and  the  precipitate  transferred  to  a  weighed  crucible  with  absolute 
alcohol,  evaporated  and  dried  at  ioo°  to  constant  weight." 
This  method  is  founded  on  that  of  Parry.  The  numbers,  quanti- 
ties and  strength  of  alcohol  agree  exactly.  The  only  new  thing  is 
the  attempt  to  use  the  fact  that  glycyrrhizic  acid  is  more  difficultly 
soluble  in  water  at  o°  than  in  water  at  room  temperature.  Against 
the  practicability  of  this  idea,  which  is  good  in  itself,  I  have  objec- 
tions which  I  will  hereafter  explain.  This  method  was  only  avail- 
able to  me  in  a  translation  (Jahresbericht  der  Pharmazie,  1910,  p. 
239).  As  I  did  not  understand  the  expression  "Technical  alcohol" 
in  the  translation,  I  requested  information  from  the  Editor  of  the 
"Chemist  and  Druggist."  I  then  learned  that  "technical  alcohol" 
(Industrial  methylated  spirits)  has  the  same  significance  as  our 
"vergallten  spiritus."  This  spirit  is  denatured  with  wood  naphtha, 
which  corresponds  to  our  pyridin  bases,  in  the  proportion  of  19:  1. 
I  considered  that  I  might  dispense  with  the  use  of  denatured  alcohol 
in  my  check  experiments  since  its  use  is  only  explainable  by  the  fact 
that  pure  alcohol  is  so  extremely  expensive  in  England.  The  mixtures 
describing  this  method,  as  regards  strength  of  alcohol,  are  exactly  the 
same  as  Parry's,  so  that  my  remarks  on  the  latter  apply.  In  my 
opinion,  one-half  hour's  standing  is  not  enough  to  precipitate  all  the 
starch  and  gums.  At  any  rate,  in  a  control  experiment  it  was  found 
that  after  standing  and  filtering  according  to  directions  there  formed 
after  a  few  hours  a  further  light  precipitate,  which  could  only  consist 
