Amjufy  ria2?arm" }        Glycyrrhizin  in  Licorice  Root.  461 
The  Tschirch-Erikson  Sugar  Determination. 
[Translator's  Note^ — Linz  goes  on  to  show  that  the  determin- 
ation of  glucose,  by  allowing  the  nitrate  from  the  glycyrrhizin  to 
stand  overnight  in  the  cold  with  Fehling  solution,  is  quite  inaccurate, 
Erikson  speaking  of  carrying  out  this  method  "according  to  Allihn," 
but  not  following  Allihn  at  all  as  to  method.  Erikson  does  not  at- 
tempt to  prove  the  accuracy  of  this  proposed  new  method,  and  she 
would  have  failed  had  she  attempted  it.  The  impossibility  of  the 
Tschirch-Erikson  method  is  so  evident,  that  the  translator  considers 
it  unnecessary  to  enter  into  the  full  details  of  Linz's  discussion. 
(P.A.H.)]. 
Linz  summarizes  as  follows : 
"The  experimental  method  of  Erikson  cannot  be  used  because  it 
does  not  give  correct  results  for  the  glucose  content  of  licorice  ex- 
tract. Erikson  has  not  attempted  to  test  her  glucose  determination 
on  pure  grape  "sugar.  Such  a  test  would  have  convinced  her  of  the 
inaccuracy  of  her  method.  She  also  takes  no  account  of  the  peculi- 
arity of  Fehling  solution  to  dissolve  the  separated  cuprous  oxide  by 
oxidation." 
[Translator's  Note. — Linz  goes  on  to  prove  that  the  method 
given  for  saccharose  (filtrate  from  glucose  determination,  boiled 
three  minutes  with  more  Fehling  solution)  is  also  quite  incorrect. 
He  shows  that  saccharose  needs  preliminary  inversion.  Also  that 
Erikson  did  not  test  the  method  on  pure,  cane  sugar,  which,  as  ex- 
pected, gave  Linz  a  negative  result. 
It  is  unnecessary  to  enter  into  Linz  experimental  details  which 
undoubtedly  refute  the  Tschirch-Erikson  method.  (P.  A.  H.)] 
Linz  says  "In  summarizing  this  part  of  Tschirch's  method,  as 
carried  out  by  Erikson,  1  cannot  avoid  accusing  the  latter  of  propos- 
ing a  new  method,  without  having  beforehand,  by  suitable  testing, 
convinced  herself  of  its  accuracy.  .  .  .  Not  only  the  glycyrrhizin 
determination,  but  also  that  of  the  individual  sugars  cannot  give  ac- 
curate results.  This  is  not  due  alone  to  the  practical  work  of  Erikson. 
Tschirch's  method  itself  unfortunately  cannot  be  used  quantitatively." 
12.  Guignard  (1912). 
"Five  g.  licorice  are  dissolved  to  500  cc.  with  water.   To  125  cc. 
of  this  solution  in  a  half  liter  beaker,  there  is  added  in  a  thin  stream, 
250  cc.  95  per  cent,  alcohol.    After  standing  24  hours,  and  filtering, 
