EXHAUSTION  OF  DRUGS  BY  PERCOLATION. 
387 
divided  into  four  classes,  viz.,  alcoholic,  hydro-alcoholic,  acetic 
and  saccharine,  but  bj  my  method  will  consist  of  only  two  classes, 
viz.,  alcoholic  and  hydro-alcoholic.  The  first  or  alcoholic,  with 
one-fourth  glycerin,  and  they  may  be  enumerated  as  follows : 
buchu,  lupuline,  valerian,  veratrum  viride,  ginger.  The  men- 
struum used  in  the  hydro-alcoholic  or  second  class,  composed.of 
one-half  alcohol,  one-fourth  water,  one-fourth  glycerin ;  under 
this  head  are  the  following,  including  the  saccharine  and  acetic 
fluid  extracts :  cimicifuga,  cinchona,  colchicum  root,  colchicum 
seed,  conium,  dulcamara,  ergot,  gentian,  hyosciamus,  ipecac, 
rhubarb,  sarsaparilla,  sarsaparilla  compound,  senna,  serpentaria, 
spigelia,  taraxacum,  ura  ursi.  The  Pharmacopoeia  directs  that 
a  fluidounce  of  a  fluid  extract  should  faithfully  represent  one 
troyounce  of  the  crude  drug,  excepting  cinchona  and  wild  cherry 
bark,  which  are  directed  to  be  one-half  the  above  strength,  both 
of  which  drugs  I  have  prepared  of  full  strength,  so  that  there 
should  be  no  exception  as  to  the  uniform  strength  of  all  adopted. 
In  order  to  prove  the  accuracy  of  my  method  in  exhausting 
cinchona  bark,  I  took  the  residue  in  percolator  after  I  had  ob- 
tained sixteen  fluidounces  of  extract  from  sixteen  troyounces  of 
the  bark,  dried  it,  redampened  it,  and  repacked  it  in  the  funnel, 
and  passed  six  pints  of  dilute  alcohol  through  it  until  it  came 
away  colorless,  then  evaporated  it  to  a  soft  extract,  which 
weighed  two  drachms,  of  a  slightly  nauseous  taste,  but  devoid 
of  bitterness,  thus  proving  conclusively  the  success  of  my  ex- 
periment, as  to  the  almost  entire  exhaustion  of  the  drug  of  all 
its  active  matter.  Cinchona  bark  has  been  admitted  to  be  one 
of  the  most  difficult  drugs  in  the  whole  catalogue  to  exhaust.  In 
making  a  fluid  extract  of  wild  cherry  bark,  I  used  a  menstruum 
composed  of  equal  parts  of  glycerin  and  water,  making  it  as  I 
said  before,  ounce  for  ounce,  and  it  will  be  found  to  faithfully 
represent  the  bark  having  the  natural  taste  and  odor  in  a  marked 
degree. 
My  method  consists  in  first  obtaining  a  powder,  moderately 
coarse,  dampening  it  with  the  menstruum,  and  then  packing 
uniformly  in  a  glass  funnel,  having  previously  placed  a  cork  in 
the  end  of  the  funnel,  also  a  piece  of  sponge  in  the  neck 
moistened  with  the  liquid ;  then  covering  the  surface  with  a  disc  of 
