Am.  Jour.  Pharm.  ) 
January,  1910.  j 
Maceration  and  Percolation. 
39 
Before  the  A.Ph.A.,  in  1858,  Prof.  Israel  G.  Grahame  read  an 
excellent  paper:  "The  Process  of  Percolation  or  Displacement,  its 
History  and  Application  to  Pharmacy,"  6  in  which  he  makes  the 
following  remarks  which  still  hold  good  to-day:  "  If  I  have  a  just 
conception  of  the  principle  upon  which  it  is  based,  it  is,  that  the 
substance  to  be  treated  and  the  menstruum  should  be  presented  to 
each  other  under  such  circumstances,  that  each  particle  of  the  sol- 
vent shall  be  fully  charged  with  soluble  matter  and  immediately 
displaced  with  another  particle,  to  become  in  its  turn  saturated  in 
a  like  manner ;  and  if  all  the  conditions  of  the  process  have  been 
properly  observed,  these  saturated  particles  collect  and  escape  from 
the  apparatus,  and  contain  to  the  fullest  possible  extent  all  that 
the  menstruum  is  capable  of  taking  up  and  even  more  than  could 
be  taken  up  by  any  other  means/'  Prof.  Grahame,  aside  from  sug- 
gesting the  use  of  the  funnel  as  a  percolator,  deserves  credit  for 
advocating  the  use  of  powdered  drugs  of  regular  and  definite  degree 
of  fineness,  as  well  as  the  proper  moistening  before  packing  it  in 
the  percolator;  both  of  these  suggestions  are  even  now  considered 
indispensable  to  successful  percolation. 
A  committee  of  the  A.Ph.A.,  consisting  of  E.  Parrish,  I.  J. 
Grahame,  and  C.  T.  Carney,  presented  a  report  on  percolation  at 
the  1859  meeting,  giving  an  account  of  the  introduction  of  the  kind 
of  titration  commonly  called  displacement  into  U.S. P.  1840,  its 
extended  use  in  U.S. P.  1850,  and  a  proposed  general  description  of 
percolation  for  U.S. P.  i860.7 
Four  pages  (pp.  3-6)  are  devoted  to  percolation  by  U.S. P.  i860, 
"  The  kind  of  filtration  known  as  percolation  or  the  process  of 
displacement,"  the  use  of  a  funnel  being  also  permissible  and  the 
uniform  powder  being  moistened  with  one-quarter  to  one-half  its 
weight  of  the  menstruum.  In  U.S. P.  1870  we  find  the  same  general 
description  (pp.  3-6),  with  the  exception  that  the  powder  is  to  be 
moistened  with  a  specified  quantity  of  the  menstruum.  In  U.S. P. 
1880  and  1890  this  chapter  has  been  improved  by  giving  more  ex- 
plicit directions,  by  passing  the  moistened  powder  through  a  sieve, 
by  the  attachment  of  a  long  rubber  tube  to  the  percolator  to  regulate 
the  flow,  by  directions  to  percolate  the  dregs  of  a  tincture,  and  by 
authorizing  repercolation  in  the  preparation  of  fluidextracts.  In 
U.S. P.  VIII  this  chapter  has  been  further  improved  by  dividing 
it  into  distinct  paragraphs,  as  percolators,  the  process,  repercolation, 
rate  of  flow,  and  maceration,  stating  under  the  latter  that  percolation 
