386 
EXHAUSTION  OF  DRUGS  BY  PERCOLATION. 
Struum  in  the  proportion  of  one  pint  for  every  sixteen  troy- 
ounces,  by  allowing  it  to  macerate  for  four  days  in  a  conical  per- 
colator, previous  to  percolation.  The  subject  is  riot  a  hastily 
formed  theory,  but  is  one  that  is  offered  as  the  result  of  actual 
experiments  with  its  results  and  residues  open  for  inspection  and 
consideration.  I  have  taken  the  liberty  to  differ  from  the  pre- 
scribed menstruum  laid  down  in  the  Pharmacopoeia,  by  following 
out  Mr.  A.  B.  Taylor's  suggestions  on  the  use  of  glycerin  as  a 
solvent  for  the  various  active  properties  of  drugs,  and  have 
been  surprised  at  the  results  obtained  from  its  use  ;  and  it  is  with 
pleasure  that  I  fully  confirm  his  views  regarding  its  use  and 
adoption  by  the  present  revisers  of  the  Pharmacopoeia,  in  the 
various  menstruums.  In  all  the  experiments  I  used  Bower's 
Glycerin.  I  have  adopted  as  a  grade  of  fineness  of  powder  for 
percolation,  that  which  is  known  in  the  Pharmacopoeia  as  mode- 
rately coarse,  or  which  will  pass  through  a  sieve  of  forty  meshes 
to  the  linear  inch,  as  one  within  the  means  of  any  retail  pharm- 
aceutist to  powder  himself.  I  find  that  about  five-eighths  of  the 
whole  quantity  can  be  obtained  of  this  fineness  by  means  of  a 
Swift's  drug  mill ;  also,  I  deem  a  greater  fineness  of  powder  than 
this  as  being  an  unnecessary  and  unwarrantable  waste  of  time 
and  physical  force,  since  maceration  is  what  is  w^anted,  and  not 
fineness  of  powder,  to  make  a  successful  percolation.  The  com- 
mon glass  funnel  I  have  found  to  be  the  best  percolator,  both  in 
point  of  convenience  and  cleanliness,  also  its  conical  shape, 
allowing  the  proper  expansion  of  the  material  whilst  macerating, 
previous  to  percolation.  The  query  has  frequently  presented 
itself  to  my  mind  as  to  what  is  a  fluid  extract,  or  what  is  it  sup- 
posed to,  or  should  it  represent.  If  I  understand  aright,  a 
fluid  extract  is  a  concentrated  tincture,  or  solution  embodying 
all  the  sensible  and  remedial  properties  of  a  drug  or  drugs,  and 
should  represent  the  drug  as  it  is  thrown  into  the  hands  of  the 
pharmaceutist  from  nature,  not  one  or  two  active  principles  of 
the  drug  alone  to  be  represented,  but  should  approximate  as 
closely  as  possible  in  its  character  and  properties  to  the  crude 
drug  itself,  in  smell,  taste,  and  remedial  effects ;  bearing  these 
points  in  mind,  I  undertook  the  following  experiments,  with  what 
success  the  samples  will  prove.    The  officinal  fluid  extracts  are 
