770 
The  Theory  of  Percolation. 
!Am.  Jour.  Pharm. 
November,  1920 
THE  THEORY  OF  PERCOLATION. 
By  James  F.  Couch, 
washington,  d.  c. 
The  process  of  percolation  stands  at  the  very  foundation  of  the 
art  of  Pharmac}^  for  it  represents  the  first  operation  in  the  prepara- 
tion of  a  plant  drug  for  medicinal  use.  The  list  of  organic  products 
is  small  whose  manufacture  does  not  involve  percolation  at  some 
stage,  usually  the  primary  process,  and  so  most  of  our  drug  compounds 
bear  witness  to  the  importance  of  this  process.  The  percolator  is  a 
truer  sign  of  pharmacy  than  the  gilded  mortar  and  pestle  which  so 
long  directed  the  wayfarer  to  the  apothecary  shop,  for  the  mortar 
suggests  little  more  than  the  grinding  together  of  the  bitter  ingredi- 
ents of  some  heroic  mixture  or  the  powdering  of  some  exotic  and  ex- 
pensive root. 
In  the  percolator,  however,  we  can  visualize  the  pharmacist's 
conquest  of  the  crude  materia  medica;  his  ability  to  select  and  reject 
among  the  constituents  of  leaves  and  barks;  the  softening  of  the 
rigors  of  medication ;  development  of  certainty  in  dosage ;  and  elimina- 
tion of  inert  and  deleterious  matters  from  pharmaceuticals.  With- 
out percolation  we  should  lose  a  valuable  means  toward  the  attain- 
ment of  these  ends. 
From  the  very  importance  of  the  process  we  should  expect  that 
pharmacists  should  give  it  much  attention  and  be  fully  informed  on 
the  various  phases  it  presents;  we  find,  however,  a  general  neglect, 
particularly  in  recent  years,  of  the  whole  subject.  Indeed,  it  has  too 
many  times  happened  that  pharmaceutical  assemblies  have  been 
bored  with  discussions  which  attempted  to  penetrate  farther  into  the 
mists  which  obscure  our  knowledge  of  the  process.  We  find  not 
only  neglect,  but  in  many  cases,  a  lamentable  ignorance  of  some  of  the 
first  principles  of  percolation.  We  see  gross  lack  of  judgment  in  the 
choice  of  menstrua;  carelessness  in  the  details  of  packing  the  drug, 
of  maceration,  or  of  rate  of  percolation,  and  frequently  no  discrim- 
ination in  the  handling  of  drugs  of  widely  different  character.  The 
work  of  extraction  in  pharmaceutical  factories  is  too  often  left  to  men 
of  small  education  who  have  but  the  slightest  knowledge  of  the  drugs 
they  are  extracting,  whose  ideas  of  the  process  are  sometimes  absurd, 
frequently  extravagant,  and  generally  erroneous,  who  do  not  ap- 
preciate the  delicacy  of  the  whole  operation  and  are,  therefore,  crude 
