METHOD  OF  PERCOLATION  FOR  FLUID  EXTRACTS.  19 
60  different  drugs,  as  the  range  of  my  field  of  experiment. 
Having  procured  a  powder  moderately  coarse,  the  next  step  is 
to  mix  the  proper  menstruum  in  the  proportion  of  sixteen  fluid 
ounces  for  every  sixteen  troy  ounces  of  the  powder  to  be  per- 
colated, preparatory  to  the  next  step  of  the  process,  which  is  to 
dampen  the  powder.  I  find  that  four  fluid-ounces  of  the  prepared 
menstruum  is  quite  sufiicient  to  dampen  sixteen  troy  ounces  of 
the  powder,  unless  the  drug  is  unusually  bulky,  and  then  six 
fluid  ounces  is  enough.  And  in  dampening  the  powder  the 
liquid  should  be  thoroughly  incorporated  by  being  well  rubbed 
uniformly  through  the  powder,  so  as  to  avoid  any  agglutination 
of  the  finer  particles,  or  the  formation  of  small  pellets.  It  is  a 
practical  error  to  have  the  powder  wet  by  using  the  whole  of 
the  menstruum,  more  especially  in  this  method,  as  the  objeet 
aimed  at  is  to  combine  both  maceration  and  percolation  slowly 
during  the  four  days  of  rest,  and  if  the  process  is  conduatedl  in 
a  glass  funnel,  it  will  be  observed,  at  the  end  of  four  days^  that 
the  active  soluble  matter  of  the  drug  has  percolated,  or  settled 
in  the  bottom  of  the  funnel,  leaving  the  upper  layer,,  or  at  least 
one-third  of  the  packed  drug,  tasteless  ;  conse€|uenitl'y  it  is  more 
easily  forced  through  by  the  displacing  liquid.  Having  damp- 
ened the  powder  as  above,  the  next  step  is  to.  proceed  to  pack 
it,  uniformly  and  moderately  tight,  in  the  percolafear.  Having 
previously  placed  a  piece  of  sponge  in  the  neek  of  the  percolator 
or  funnel,  moistened  with  the  menstrisum,  then  cover  over  the 
surface  of  the  drug  a  disc  of  paper  and  proceed  to  pour  on  the  re- 
maining twelve  fluid  ounces  of  menstruum,  allowing  it  to  he- 
slowly  absorbed  or  percolated  through  the  packed  drug.  When 
the  liquid  is  observed  to  begin  to  saturate  the  piece  of  sponge 
in  the  bottom  of  the  funnel,  place  a  cork  tightly  in  the  orifice 
of  the  neck  of  the  funnel  and  allow  the  whole  to  macerate  four 
four  days.  At  the  end  of  that  time  remove  the  cork,  and  pour 
over  the  surface  of  the  drug  in  the  funnel  a  displacing  liquid  cor- 
responding to  the  menstruum  used,  omitting  glycerin,  as,  for 
instance,  if  the  menstruum  was  alcohol  and  glycerin,  let  the  dis- 
placing liquid  be  strong  alcohol ;  if  alcohol,  water  and  glycerin, 
use  for  displacing  liquid  dilute  alcohol ;  if  water  and  glycerin 
(as  used  for  wild  cherry  bark)  use  cold  water  as  the  displacing 
