106  Active  Constituents  of  Podophyllin,         { "^"'Mr" 'issJ.'"'"' 
of  podopliyllotoxin,  /.  e,,  when  treated  as  above  mentioned,  it  yields 
picropodophyllin  in  the  form  of  snow-white  crystals,  etc.  By  the 
precipitation  of  the  alcoholic  solntion  of  this  horn-like  mass,  pnlveru- 
lent  podophyllotoxin  is  obtained ;  this  succeeds  still  better  when  the 
solution  in  chloroform  is  precipitated  with  petroleum  ether.  The  ele- 
mentary analysis  of  podophyllotoxin  is  given  in  the  further  description 
of  picrodophyllinic  acid.  Podophyllotoxin  is  admirably  assimilated 
by  the  animal  organism,  as  well  by  the  introduction  of  its  solutions  in 
very  dilute  alcohol  into  the  stomach  as  also  by  sub-cutaneous  injection. 
The  action  is  precisely  the  same  as  with  picropodophyllin,  since  this 
forms  exclusively  the  active  principle  of  podophyllotoxin,  the  latter 
acts  even  more  quickly,  as  in  the  organism  the  picropodophyllin  cannot 
crystallize  from  the  podophyllotoxin  solutions  unless  free  alkalies  are 
present  in  the  stomach,  or  have  been  added  to  the  medicine  containing 
the  podophyllotoxin ;  the  separation  of  the  picropodophyllin  then 
takes  place  in  proportion  to  the  amount  of  free  alkali  present.  .Pure 
podophyllotoxin  forms  a  white,  resinous  powder,  which  is  completely 
soluble  in  chloroform,  and  in  the  latter  solution  the  addition  of  ether 
should  not  produce  a  flocculent  precipitate,  which  would  indicate  an 
admixture  of  podophyllinic  acid.  The  podophyllotoxin  solution  should 
also  not  produce  a  dark-brown  color  with  ferric  chloride,  indicative  of 
an  admixture  of  podophylloquercetin. 
Picropodophyllinic  acid  is  in  respect  to  its  action  without  significance,, 
but  is  so  far  of  interest,  as  it  holds  in  solution  the  only  active,  and  in 
water  insoluble,  constituent  of  the  officinal  podophyllin, — the  crystal- 
line picropodophyllin, — and  renders  the  latter  for  the  animal  organ- 
ism capable  of  assimilation.  The  acid  is  with  great  difficulties  freed 
from  the  last  traces  of  picropodophyllin,  which,  after  the  neutraliza- 
tion of  the  picropodophyllinic  acid  by  means  of  alkalies,  crystallizes 
out.  It  is  a  resinous  acid,  separates  on  the  addition  of  water  to  the 
alcoholic  solution,  and  is  precipitated  in  a  flocculent  form  when  the 
aqueous  solutions  of  its  compounds  with  the  alkaline  earths  are  acidu- 
lated. If  these  flocculent  precipitates  be  dried,  they  form  granules 
of  a  horny  appearance,  which  are  readily  soluble  in  alcohol,  chloro- 
form and  ether.  After  the  decomposition  of  the  above  compounds  by 
acids,  a  portion  of  the  picropodophyllinic  acid  remains  at  first  dissolved 
in  the  water,  but  is  gradually  also  precipitated  in  a  flocculent  form. 
In  hot  water  the  acid  is  soluble,  but  separates  again  upon  cooling.  Of 
more  interest  are  the  relations  of  picropodophyllinic  acid  to  picropo- 
