^""Mr^'issl:'™  }        Active  Constituents  of  Podophyllin.  105 
ing  point  is  from  200  to  210°C. ;  at  200^^0.  it  is  not  decomposed  but 
forms  a  soft  crystalline  mass,  possessing  all  the  properties  of  picropodo- 
phyllin.  Several  elementary  analyses  gave  carbon  67*71,  hydrogen 
5-31  and  oxygen  26'98. 
Podophyllotoxin  is  a  very  bitter,  amorphous  substance,  soluble  in 
dilute  alcohol  and  hot^  water ;  from  the  latter  solution  it  is  precipitated 
very  slowly  upon  cooling  in  the  form  of  fine  flakes,  so  that  the  water 
retains  the  bitter  taste  for  24  hours.  From  the  alcoholic  solution  it  is 
likewise  precipitated,  but  very  slowly  as  an  extremely  fine  powder  on 
the  addition  of  a  considerable  amount  of  water.  It  is  most  readily 
soluble  in  chloroform,  but  is  also  soluble  in  ether  when  completely  free 
from  podophyllinic  acid  ;  it  is  insoluble  in  petroleum  ether,  and  has  a 
slightly  acid  reaction.  Alcoholic  solutions  of  podophyllotoxin  are 
completely  neutralized  by  warming  with  the  alkaline  earths.  Aqueous 
solutions  of  the  caustic  alkalies,  potassa  and  soda,  neutralize  the  acid 
portion  of  podophyllotoxin  without  warming;  ammonia  water  neu- 
tralizes likewise,  and  after  its  evaporation  the  acid  reaction  again 
appears.  On  the  neutralization  of  the  etherial  solutions  of  podophyl- 
lotoxin with  lime  or  baryta  water,  a  portion  of  it  passes  into  the 
aqueous  solution  while  the  other  portion  crystallizes  from  the  ether  in 
the  form  of  white  silky  needles.  With  the  aid  of  the  microscope  this 
phenomenon  can  be  observed  immediately  after  the  addition  of  the 
solution  of  the  alkaline  earth  to  the  etherial  podophyllotoxin  solution. 
The  crystals  thus  formed  are  picropodophyllin.  When  the  solution 
of  podophyllotoxin  in  ammonia  water  or  in  dilute  alcohol,  in  which 
picropodophyllin  is  insoluble,  is  neutralized,  the  latter  crystallizes  in 
small,  fine,  stellate  groups  of  crystals,  which  with  the  resinous  picro- 
podophyllinic  acid  (accompanying  the  podophyllotoxin)  form  spheroidal 
granules.  These  spheroidal  formations  solidify  in  saturated  alkaline 
solutions  of  picropodophyllinic  acid  to  a  jelly-like  mass.  If  the  alka- 
line compound  of  the  acid  of  podophyllotoxin  is  now  decomposed  by 
any  acid  which  with  the  alkali  forms  a  soluble  salt,  then  one  can  obtain 
separately  the  crystalline  picropodophyllin,  as  also  the  acid  of  the 
podophyllotoxin  with  which  the  separated  picropodophyllin  w^as  asso- 
ciated. The  acid  of  the  podophyllotoxin  is  the  above-mentioned 
picropodophyllinic  acid.  The  separated  picropodophyllin  becomes 
dissolved  in  the  pi(;ropodophyllinic  acid  by  long-continued  heating, 
and  by  the  evaporation  of  this  solution  to  dryness,  an  amorphous, 
resinous  substance  is  again  obtained  which  possesses  all  the  j)roperties 
