^'"£^■1882.™  }        Active  Constituents  of  Podophyllin,  107 
dophyllin,  which  latter  is  concealed  to  a  certain  extent  by  the  separa- 
tion of  the  former^  and  this  behavior  causes  the  gelatinous-like 
coalescence  of  officinal  podophyllin  on  treatment  with  alkalies. 
If  podophyllotoxin,  having  an  acid  reaction,  be  mixed  with  the 
aqueous  solution  of  an  alkaline  earth,  e.  g.,  with  lime  or  baryta  water,, 
and  warmed  upon  the  water-bath  with  the  occasional  addition  of  fresh 
portions  of  the  alkaline  earth  solution,  until  the  podophyllotoxin, 
which  slowly  dissolves,  has  become  perfectly  neutralized,  a  solution 
is  formed  which  is  only  slightly  turbid,  from  small  amounts  of  impuri- 
ties ;  upon  cooling,  this  solution  solidifies  to  a  gelatinous  mass,  which,, 
from  a  more  concentrated  solution,  can  be  obtained  in  the  form  of 
adhering  lumps.    If  to  the  hot  filtered  solution  an  acid  be  gradually 
added,  forming  with  the  barium  or  calcium  a  soluble  salt,  a  flocculent 
precipitate  is  produced  which,  under  the  microscope,  appears  as  a 
granular,  transparent,  gelatinous  mass,  in  the  spheroidal  granules  of 
which  exceedingly  delicate,  stellate  crystalline  forms  may  be  observed. 
The  liquid  is  now  filtered,  and  the  precipitate  on  the  filter  is  washed 
until  the  acid  is  completely  removed.    The  residue  upon  the  filter  is 
dissolved  in  water  by  the  aid  of  heat,  and  filtered  into  a  previously 
warmed  evaporating  dish.    Upon  slowly  cooling,  snow-white,  radi- 
ating groups  of  crystals  are  formed  within  the  gelatinous  mass,  and 
the  entire  substance  becomes  subsequently  like  jelly.    Under  the 
microscope  the  entire  mass  is  seen  to  consist  of  the  previously  men- 
tioned spheroidal  granules,  mixed  with  delicate,  needle-like  bundles ; 
the  crystals  are  picropodophyllin,  while  the  transparent,  gelatinous, 
granular  mass  consists  of  resinous  picropodophyllinic  acid,  in  which  a 
portion  of  the  picropodophyllin  is  dissolved  and  another  portion  crys- 
tallized ;  for  free  picropodophyllin,  when  not  dissolved  in  the  resinous 
picropodophyllinic  acid  or  glacial  acetic  acid,  can  only  appear  in  the 
presence  of  water  in  the  crystalline  form.    When  the  water  is  removed 
from  the  gelatinous  mass  by  evaporation  on  the  water-bath,  there 
appear  with  the  increased  concentration  snow-white,  needle-shaped 
crystals,  which,  after  the  complete  removal  of  the  water,  fill  the  entire 
vessel,  and  form  a  compact  felt-like  aggregation.    The  reaction  of 
this  crystalline  mass  is  acid,  and  in  consideration  of  the  uniformity 
of  the  snow-white  crystals,  they  could  be  easily  presumed  to  be  the 
crystallized  picropodophyllinic  acid.    The  author  himself  was  led  to 
this  incorrect  supposition,  but  finally  succeeded  in  separating  from  the 
crystalline  mass  two  special  bodies.    On  treating  the  mass  with  ammo- 
