488  Oleoresin  of  Male  Fern.  { Am-£tuyi8p9?arm- 
composition  of  this  substance  has  been  variously  given  fLuck^ 
C26H30O9,  and  Grabowski,  CuH1805) ;  the  latter  points  out  that  by 
decomposition  with  a  caustic  alkali  butyric  acid  and  phloroglucin 
are  produced,  and  regards  it  as  a  dibutyrylphloroglucin  ;  the  former 
was  subsequently  inclined  to  regard  it  as  an  anhydride,  since  in 
several  of  its  compounds,  as,  for  instance,  its  lead  salt,  an  additional 
atom  of  water  is  included.  In  addition  to  filicic  acid,  the  ethereal 
extract  of  male  fern  contains  a  volatile  oil,  resin,  and  other  princi- 
ples, and  some  doubt  has  arisen  whether  the  activity  of  the  root 
does  not  in  part  depend  on  these ;  for  it  has  been  noticed  that  the 
crystalline  filicic  acid  does  not  always  seem  to  possess  very  active 
properties. 
Carlblom  found  it  sometimes  acted  as  an  anthelmintic,  sometimes 
it  was  without  effect,  and  another  observer,  Rulle,  noted  that  when 
he  gave  an  impure  filicic  acid,  made  by  simply  treating  the  extract 
with  ammonia  and  then  precipitating  the  filicin  by  hydrochloric 
acid,  he  obtained  an  active  anthelmintic,  but  when  he  purified  and 
crystallized  the  filicic  acid  in  the  precipitate  it  seemed  to  have  no 
effect. 
Poulsson's  investigations  explain  this  apparent  anomaly.  He,  too> 
finds  that  the  impure  precipitated  filicic  acid  is  an  active  poison  to 
rabbits,  but  the  crystalline  filicic  acid  does  not  produce  toxic  symp- 
toms in  a  rabbit  even  in  doses  of  twenty-two  grains.  He  finds, 
however,  that  if  the  pure  filicic  acid  is  dissolved  in  an  alkali  and' 
precipitated  by  an  acid  the  amorphous  precipitate  obtained  is  a 
poison  acting  like  the  liquid  extract.  His  investigations  have  led 
him  to  the  conclusion  that  the  amorphous  substance  is  the  true 
filicic  acid,  and  that  it  has  the  composition  C3.H42013.  The  crystal- 
line substance  hitherto  known  as  filicic  acid  is  the  anhydride  of 
filicic  acid  (C35H40O12)  and  he  proposes  to  call  it  fiilicin. 
Filicin  crystallizes  in  small  yellow  rhombic  plates,  is  insoluble  in 
water  and  quite  insoluble  in  cold  alcohol,  but  dissolves  in  boiling 
alcohol.  It  is  more  or  less  soluble  in  ether,  amyl-alcohol,  benzol, 
chloroform,  and  fat  oils.  In  alkalies  in  the  cold  it  is  only  soluble  in 
considerable  excess  of  the  solvent.    It  melts  at  184-5°. 
Filicic  acid  is  an  amorphous  white  powder  without  taste  or  smell. 
It  is  soluble  in  the  same  solvents  as  the  anhydride,  but  more  readily, 
and  it  is  especially  soluble  in  cold  alcohol;  it  is  very  easily  soluble 
in  alkalies  and  olive  oil.    At  iOO°  it  becomes  of  a  straw  yellow 
