Am.  Jour.  Pharm. 
Oct.,  1891. 
Oleoresin  of  Male  Fern. 
489 
'  color,  but  is  not  decomposed;  it  melts  at  1250.  Filicic  acid  is 
easily  transformed  into  the  anhydride.  If  a  concentrated  ethereal 
solution  be  boiled  crystals  of  the  anhydride  are  precipitated,  and  in 
a  few  days  a  further  quantity  falls  down. 
Poulsson  has  investigated  the  pharmacological  action  of  filicic  acid 
on  the  skeletal  muscles,  on  the  heart,  and  on  the  nervous  system. 
In  the  frog  (Rana  temporaria)  a  weak  alkaline  solution  injected  sub- 
cutaneously  caused  ejection  of  the  contents  of  the  stomach  and  intes- 
tines, motor  paresis,  twitching  of  the  muscles,  and  irregular  action  of 
the  heart,  which  tends  to  distension  in  diastole  and  eventual  cessa- 
tion of  the  beat.  Twitching  did  not  occur  after  curare  or  section  of 
the  sciatic  nerve.  Six  to  seven  mg.  cause  death  in  one-half  to  three- 
quarters  of  an  hour;  two  mg.  in  about  twelve  hours.  R.  esculenta 
are  not  so  easily  affected.  The  paralysis  produced  by  filicic  acid  is 
central  in  origin,  for  the  muscles  react  to  the  induced  current  as  well 
after  as  before  the  poisoning,  and  even  after  death  from  filicic  acid 
they  contract  well  to  the  faradic  current.  The  muscle  curve  is  not 
much  altered,  nevertheless  Poulsson's  experiments  show  that  the 
elasticity  and  capacity  of  work  of  the  muscle  is  decreased,  and,  there- 
fore, the  filicic  acid  is  a  muscle  poison.  Poulsson  is  of  opinion  that 
filicic  acid  depresses  the  heart's  action  in  the  frog  partly  owing  to  its 
action  on  the  muscle,  and  partly  owing  to  its  influence  on  the  auto- 
matic ganglia.  It  decreases  the  strength  of  the  beat,  and  causes 
arrest  in  diastole.  The  local  application  of  atropine  will,  under 
some  conditions,  excite  contractions  again. 
The  intravenous  injection  of  one  decigramme  in  a  rabbit  causes 
marked  muscular  relaxation  owing  to  spinal  paresis,  but  soon, 
increased  reflex  excitability  is  noticed,  later  on  twitching,  and  some- 
times tetanus.  The  heart  beats  after  the  respiratory  muscles  cease 
to  act,  yet  artificial  respiration  will  not  prolong  life. 
Given  by  the  stomach  jy2  grains  is  a  fatal  dose.  It  is,  however, 
so  slowly  absorbed  from  the  intestine  that  from  12  to  20  hours  the 
animal  may  remain  well.  Then  weakness  of  the  hinder  extremities 
comes  on,  and  symptoms  follow  similar  to  those  described  as  the 
effect  of  injection.  Death  occurs  in  24  to  48  hours.  The  action  is 
more  rapid  if  filicic  acid  is  given  in  oil.  Fern  extract  produces  the 
same  effects  as  filicic  acid. 
After  death  the  mucous  membrane  of  the  stomach  and  intestines 
is  found  turgid  and  hyperaemic — even  after  subcutaneous  injection 
