408'  Ammoniac al  Compound  of  Glycyrrhizin.  {^"'siprxsyt'"'' 
glycyrrhizate  of  ammonia.  This  precipitate  is  washed  rapidly  on  a  fine 
cloth  with  a  mixture  of  equal  parts  of  alcohol  and  ether,  pressed  and 
dried  in  a  current  of  warm  air  or  over  sulphuric  acid.  The  ammoni- 
acal  glycyrrhizin  so  obtained,  which  the  author  considers  to  represent 
the  true  sweet  principle  of  licorice  root,  is  of  a  yellowish  tint,  very 
light,  and  en.tirely  and  rapidly  soluble  in  water,  to  which  it  communi- 
cates an  amber  color  and  an  extremely  sweet  taste.  It  can  be  rendered 
more  dense  by  re-dissolving  it  in  a  small  quantity  of  water,  and  evap- 
orating the  solution  on  a  plate  or  on  a  glass.  It  is  thus  obtained  ir> 
very  brittle,  translucent,  shining  scales,  which  are  readily  detached.  In 
either  form  pure  ammoniacal  glycyrrhizin  is  unalterable  in  the  air,  non- 
hygroscopic,  and  dissolves  nearly  instantaneously  in  cold  water,  forming 
a  pale  amber  solution,  having  an  intensely  sweet  taste.  The  solution 
froths  upon  agitation. 
One  gram  of  pure  ammoniacal  glycyrrhizin  dissolved  in  a  litre 
of  water  gives  a  solution  which  is  very  sweet.  The  same  quantity 
dissolved  in  two  litres  of  water  gives  a  solution  that  is  more  agreeable 
to  the  taste  and  resembles  closely  that  of  the  licorice  root.  If  a  very 
small  portion  of  ammoniacal  glycyrrhizin  be  placed  upon  the  tongue  it 
develops  instantaneously  a  sweet  taste,  so  strong  as  to  be  disagreeable 
to  most  persons. 
That  glycyrrhizin  itself  is  nearly  insoluble  in  water  and  insipid,  and 
only  acquires  its  sweet  taste  when  in  combination  with  an  alkali,  may 
be  shown  by  taking  a  solution  of  i  part  of  ammoniacal  glycyrrhizin  in 
300  of  water,  which  would  be  a  very  sweet  liquor,  and  adding  to  it 
sufficient  of  any  acid  to  saturate  the  ammonia,  and  set  free  the  glycyr- 
rhizin. The  liquor  immediately  loses  its  sweet  taste,  and  after  a  time 
flocks  of  glycyrrhizin  are  precipitated.  With  more  concentrated  solu- 
tions (i  in  100  or  I  in  50),  and  acetic  acid,  the  precipitate  forms  more 
slowly  as  a  firm  transparent  jelly.  This  jelly  has  no  taste,  but  if  there 
has  been  no  excess  of  acid  used  a  slight  taste  of  licorice  is  gradually 
developed  in  the  mouth,  due  to  the  natural  alkalinity  of  the  saliva.  A 
small  quantity  of  ammonia  re-dissolves  the  flocks  and  restores  instan- 
taneously the  primitive  taste. 
The  author  considers  that  these  facts  explain  simply  several  phenom- 
ena that  have  hitherto  been  obscure.  Frequently  licorice  is  met  with 
that  has  but  little  taste,  especially  when  the  drying  of  the  root  has  been 
slow  or  incomplete,  or  when  it  has  been  kept  in  a  damp  place.  The 
result  he  attributes  to  a  commencement  of  fermentation  by  which  acid 
