Am.  Jour.  Pharm.  1 
April,  1910.  J 
Correspondence. 
193 
Of  course  the  ordinary  process  of  percolation  always  involves 
a  certain  amount  of  maceration.  The  Pharmacopoeia  directs  that  a 
drug  shall  be  moistened,  allowed  to  swell  through  the  absorption 
of  the  liquid,  then  be  transferred  and  properly  packed  in  a  per- 
colator, be  covered  with  menstruum  and  allowed  to  macerate  or 
"  soak  "  for  a  certain  length  of  time ;  and  the  percolation  is  then 
carried  out  in  the  usual  way.  Such  maceration  as  this,  where  only 
a  relatively  small  amount  of  liquid  is  employed,  is  very  necessary. 
Even  where  the  menstruum  is  allowed  to  slowly  flow  upon  the 
drug  in  process  of  percolation,  maceration  is  taking  place  unless 
the  passage  of  the  liquid  through  the  drug  is  carried  on  with  undue 
rapidity.  Maceration,  however,  involving  the  use  of  an  excess  of 
liquid  and  long  standing,  we  consider  wholly  unnecessary  and  we  do 
not  find  it  desirable  even  in  the  manufacture  of  tinctures. 
The  above  statement  is  the  outgrowth  of  long  and  continued 
experience.  You  may  perhaps  remember  that  in  the  beginning  all 
of  our  fluids  were  prepared  by  this  process  of  maceration.  The 
drugs  were  allowed  to  stand  in  contact  with  the  liquid  for  days, 
sometimes  for  weeks,  the  liquid  was  drained  oft,  and  the  marc 
was  then  placed  in  a  hydraulic  press  and  the  remaining  portion 
of  the  liquid  contents  were  pressed  out.  This  old  process,  while  yield- 
ing very  good  results,  was  found  to  be  very  expensive  in  time  through 
the  loss  of  menstruum,  and  moreover  yielded  fluids  which  showed 
a  marked  tendency  to  precipitation  on  standing. 
Prof.  Leo  Eliel,  South  Bend,  writes :  There  has  been  so  much 
said  and  written  on  the  relative  value  of  percolation  and  macera- 
tion in  pharmaceutical  operations,  that  it  would  seem  as  though 
the  last  word  had  been  said.  This  subject  has  been  under  discussion 
for  fifty  years  to  my  knowledge.  But  the  fact  that  you  are  taking 
up  this  subject  for  discussion  at  your  pharmaceutical  meeting  would 
seem  to  show  that  there  is  still  something  to  differ  on. 
As  you  are  asking  for  my  personal  experience,  I  would  say  that 
it  is  decidedly  in  favor  of  the  process  by  percolation  ;  my  reason 
for  this  being  that  by  this  process  it  is  possible  to  have  a  definite 
quantity  of  the  soluble  drug  constituents  in  a  definite  quantity  of 
fluid.  This  is  not  the  case  in  maceration,  as  there  will  always  be 
an  indefinite  amount  of  soluble  constituents  left  in  the  marc.  How- 
ever, I  might  say  that  the  official  directions,  in  many  cases  at 
least,  do  not  allow  a  sufficient  length  of  time  for  maceration  before 
percolation.    My  practice  is  to  macerate  for  a  period  of  from  three 
