Amjune,riSarmi        Glycyrrhizin  in  Licorice  Root.  395 
He  emphasizes  particularly,  that  he  did  not  make  this  experi- 
ment with  pure  acid,  for  the  reason  that  such  a  substance  is  not  ob- 
tained in  the  quantitative  determination.  Capin  in  his  dissertation, 
made  detailed  researches  on  the  solubility  determination,  but  the 
conclusions  which  he  drew  are  partly  incorrect.  I  will  here  only 
consider  his  solubility  determinations.  I  will  speak  of  their  applica- 
tion to  his  proposed  method  of  determining  glycyrrhizic  acid  when 
I  discuss  that  subject. 
When  one  adds  sulphuric  acid  to  precipitate  an  extract  of  licorice 
or  a  glycyrrhizin  solution,  the  supernatant  liquid  remains  colored. 
From  this  Capin  concludes :  "If  now  the  total  glycyrrhizic  acid  had 
been  precipitated  by  the  addition  of  sulphuric  acid,  it  is  evident  that 
the  liquid,  after  filtration,  would  not  show  the  least  color."  This 
conclusion  is  incomprehensible.  It  would  be  true,  and  only  then  con- 
ditionally, if  pure  glycyrrhizic  acid  were  colored,  or  better,  black. 
But  Capin  has  written  the  above  statement  in  spite  of  having  read 
the  researches  of  Tschirch !  In  order  to  determine  its  solubility, 
Capin  shakes  up  25  grams  glycyrrhizic  acid  (impure,  washed  with 
water,  alcohol  and  ether)  with  200  cc.  water,  and  allows  the  liquid 
to  stand  for  24  hours.  He  then  niters,  and  cools  the  clear  solution 
to  o°  in  a  mixture  of  ice  and  salt.  A  further  precipitate  is  formed, 
which  is  filtered  off  through  a  funnel  kept  at  o°.  He  then  dries  20  cc. 
of  this  filtrate  to  constant  weight,  and  obtains  0.110  grams  of  residue 
which  corresponds  to  a  content  of  0.55  per  cent,  (not  0.575  Per  cent., 
as  is  stated  in  Capin's  dissertation  in  consequence  of  a  misprint). 
Under  the  same  experimental  conditions,  he  then  determines  that  the 
solubility  factor  at  150  amounts  to  0.575  Per  cent.  These  two  num- 
bers, as  shown  above,  have  become  mixed,  and  the  error  has  been 
carried  into  the  French  journals  in  part,  for  example,  in  the  Reper- 
toire de  Pharmacie,  III,  24,  p.  14.  In  consequence  of  this  error, 
Anquet  has  called  the  attention  of  the  author  to  the  unusual  proced- 
ure in  prescribing  a  temperature  of  o°  although  the  solubility  ac- 
cording to  his  results,  is  higher  at  o°  than  at  150.  A  comparison  of 
the  dissertation  with  the  Bulletin  des  Travaux  de  la  Societe  pharma- 
ceutique  de  Bordeaux  shows  at  once  that  it  is  only  a  question  of  an 
oversight  or  a  printer's  error.  The  conclusions  of  Anquet  are  there- 
fore not  justified. 
The  observation  of  Capin,  that  a  clear  solution,  from  which  the 
glycyrrhizin  has  been  precipitated,  separates  a  further  quantity  of  the 
