ON  PERCOLATION  OR  DISPLACEMENT. 
317 
the  extracts  being  clear  below.  Agitation  easily  reunites  the  super  stratum 
with  the  clear  extract. 
We  confess,  however,  that  our  experience  is  in  favor  of  making  valerian, 
buchu,  cimicifuga  and  allied  drugs,  owing  to  their  virtues  to  oleo-resinous 
principles,  with  an  alcoholic  menstruum,  and  with  as  little  evaporation  as 
possible.  The  views  of  Prof.  Grahame,  (see  page  379,)  in  regard  to  fluid 
extract  of  valerian,  appear  to  meet  the  case,  and  if  by  the  aid  of 
careful  percolation  we  can  get  nine-tenths  of  the  active  matter  of  a  drug 
in  nine-tenths  of  the  bulk  of  the  fluid  extract  to  be  made,  we  believe  the 
problem  will  be  solved,  so  far  as  this  class  is  concerned ;  but  we  must  be 
careful  that  we  do  extract  all  that  the  physician  needs  in  the  preparation. 
There  are  cases  where  the  solvent  power  of  glycerin  may  come  into  play 
when  the  retention  of  alcohol  in  the  fluid  extract  may  prove  objectionable. 
It  is  certainly  very  desirable  that  fluid  extracts  should  be  homogeneous 
solutions,  and  to  this  end  let  us  strive  to  attain,  if  it  be  possible. 
ON  PERCOLATION  OR  DISPLACEMENT. 
By  William  Procter,  Jr. 
It  has  long  been  conceded  that  the  process  of  displacement 
or  percolation,  as  developed  by  the  Boullays  of  Paris  in  1833, 
is  calculated,  in  proper  hands,  to  work  a  complete  revolution  in 
the  manipulations  of  extraction,  as  applied  to  pharmacy.  Those 
who  have  understood  it  have  not  failed  to  get  results,  which,  if 
not  entirely  satisfactory,  have  so  far  exceeded  the  ancient  me- 
thods of  maceration  and  digestion,  that  they  have  won  for  it  the 
preference.  Why  then,  it  has  been  asked,  has  not  this  process 
been  universally  employed  ?  Why,  in  two  successive  revisions  of 
the  Pharmacopoeia,  has  it  been  but  partially  adopted,  giving  the 
preference  to  the  old  methods  ?  I  believe,  the  reason  will  be 
found  in  the  fact  that  the  practice  of  this  process  involves  more 
preparatory  labor  and  stricter  attention  to  certain  conditions, 
without  which  it  is  a  failure,  and  that  it  was  the  want  of  confi- 
dence by  the  Pharmacopoeial  authorities  in  the  ability  and  will- 
ingness of  those  who  have  in  charge  the  business  of  pharmacy, 
faithfully  to  carry  out  these  conditions,  that  caused  percolation 
to  be  offered  as  an  alternative,  instead  of  being  made  the  normal 
process  of  extraction.  The  very  simplicity  of  maceration  ren- 
ders it  easily  understood  by  the  novice,  and  any  irregularity  in 
the  preparation  of  the  materials  is  overcome  in  a  great  degree, 
by  the  longer  time  devoted  to  the  process. 
