866 
The  Theory  of  Percolation. 
!Am.  Jour.  Pharm. 
December,  1920. 
process  suitable  for  the  extraction  of  alkaloid  drugs.  Bird^  approved 
of  the  process  and  Musset^  recommended  repercolation  for  the 
preparation  of  •  fiuidextracts.  Scoville^  stated  that  repercolation 
is  satisfactory  for  the  extraction  of  resinous  drugs. 
In  expert  hands  the  process  of  Squibb  gives  excellent  results 
with  menstrua  which  do  not  contain  a  large  proportion  of  water. 
In  the  extraction  of  those  drugs  which,  like  gentian,  rhubarb,  kino, 
and  Phytolacca,  yield  large  quantities  of  extractive  soluble  in  diluted 
alcohol  the  simpler  process  is  preferable  but  repercolation  may 
PROF.  C.  LEWIS  DIEHL 
A  painstaking  worker  on  fiuidextracts  and  the  processes  of  percolation. 
be  applied  to  advantage  in  the  extraction  of  ginger,  cimicifuga, 
ergot,  hydrastis,  gelsemium,  and  especially  where  such  solvents  as 
acetone,  chloroform,  ether,  or  ligroin  are  used  as  menstrua. 
INTERRUPTED  PERCOLATION. 
Interrupted  or  suspended  percolation  is  the  name  given  to  a 
variation  of  the  ordinary  process  of  simple  percolation  by  C.  A. 
Seifert."^    The  practise  in  this  case  is  founded  upon  sound  principles 
^  Pharm.  Jour.  54,   158,  (1894). 
2  Pharm.  Centr.  1897,  862;  Proc.  A.  Ph.  A.  1898,  681. 
^  Proc.  A.  Ph.  A.  1910,  1 1 14.  (Discussion.) 
*  Proc.  Calif.  Ph.  A.  1892,  123. 
