Am.  Jour.  Pharm.  ) 
December,  1920.  ) 
The  Theory  of  Percolation. 
863 
This  idea  was  not  favorably  received  however,  and,  in  the  next 
year/  Squibb  pubHshed  the  details  of  his  process  of  repercolation, 
"Improved  Process  for  Officinal  Fluid  Extract  of  Buchu,"  following 
it  with  an  application  to  cinchona^  and,  much  later,  with  an  exten- 
sive study  which  may  well  be  considered  a  pharmaceutical  classic.^ 
In  the  earlier  directions  for  his  process  Squibb  adopted  the  custom- 
ary evaporation  of  weak  percolate ;  later  he  revised  the  procedure  so 
that  a  fluidextract  was  obtained  directly  from  the  process  with- 
out evaporating  and  the  weak  percolates  were  preserved  and  used 
on  the  next  batch  of  drug. 
DR.  E.  R.  SQUIBB 
Originator  of  the  process  of  repercolation. 
At  about  the  same  time  a  similar  process  was  developed  in 
England  by  R.  W.  Giles.^ 
The  fundamental  principle  of  repercolation  is  to  saturate  thor- 
oughly the  first  fractions  of  percolate  by  mixing  them  as  macer- 
ating menstruum  with  fresh  portions  of  the  drug.  In  the  revised 
process,  the  drug  is  divided  into  three  or  four  portions  which  may  be 
of  equal  weight  or  which  may  decrease  in  weight  from  the  first  to 
the  last  to  be  treated;  the  first  portion  is  percolated  in  the  ordinary 
fashion  and  a  definite  amount  of  percolate  reserved;  a  second 
1  Proc.  A.  Ph.  A.  1866,  81. 
2  Proc.  A.  Ph.  A.  1867,  391. 
3  This  Journal,  Vol.  50,  209,  (1878).    Ephemeris,  3,  993,  (1887). 
^  Pharm.  Jour.  26,  219,  (1866);  33,  521,  (1873).    Proc.  A.  Ph.  A.  1867,  140, 
