868 
The  Theory  of  Percolation. 
[  Am.  Jour.  Pharm. 
(    December,  1920. 
Table. 
Senna.  Cinchona.  Ginger. 
S. 
G. 
Per  1 
Cent. 
S. 
G. 
Per  < 
Cent. 
S. 
G. 
Per  Cent. 
Fraction  i 
025 
15 
00 
0. 
952 
1 1  , 
66 
0. 
885 
25- 
00 
2 
I . 
050 
22  . 
•50 
0. 
976 
26. 
66 
0 . 
05c 
1  ■ 
50 
3 
044 
20 
.00 
0. 
994 
28, 
33 
0. 
842 
3 
33 
4 
I . 
036 
20 
.00 
I . 
020 
38 
.00 
0 . 
836 
I 
.66 
5 
I . 
018 
16 
.CO 
010 
31 
.66 
0. 
827 
0 
.83 
Finished  Fldext. 
I . 
035 
18 
.00 
I . 
000 
26 
.66 
0. 
846 
6 
.66 
Seifert  does  not  state  the  quantities  of  drug  taken  nor  the  vol- 
ume of  percolate  collected  but  inspection  of  his  paper  leads  to  the 
opinion  that  he  used  i,ooo  Gms.  of  drug  and  collected  200  Mil.  por- 
tions of  percolate.  He  suspended  the  percolation  for  24  hours 
between  the  collection  of  each  fraction  of  percolate  and  did  not 
vary  this  period  during  the  process.  His  results  plainly  show  the 
advatages  of  alternate  periods  of  maceration  and  percolation. 
Many  years  earlier  Alonzo  Robbins^  investigated  the  effect  of 
interrupting  percolation  in  connection  with  some  other  work  and 
his  results  led  him  to  conclude  that  no  advantage  came  of  it.  Rob- 
bins,  however,  did  not  give  the  method  a  fair  trial;  he  shortened 
the  period  of  maceration  as  the  time  went  on  instead  of  lengthening 
it  or  keeping  it  uniform  and  also  abandoned  the  macerating  after 
four  periods  of  maceration.  Nevertheless  a  critical  scrutiny  of  his 
results  show  a  slight  advantage  in  the  interrupted  process. 
In  the  same  year  Uoyd^  published  the  results  of  an  experi- 
ment on  the  extraction  of  cimicifuga  by  what  he  termed  "inter- 
rupted" percolation,  proceeding  as  follows:  24  troy  ounces  of 
drug  were  moistened  and  packed  and,  without  macerating  one  fluid- 
ounce  of  percolate  was  run  off.  The  operation  was  then  suspended 
and  the  drug  was  allowed  to  macerate  for  sixteen  hours  at  100°  F. 
Then  seven  portions  of  one  fluidounce  each  were  percolated  off. 
The  drug  was  again  macerated  one  day  and  eight  fluidounce 
portions  of  percolate  were  collected.  After  32  fractions  had  been 
collected  the  percolate  was  taken  in  two-ounce  fractions  until  the 
drug  was  exhausted.  Results  from  this  experiment  are  plotted 
in  Chart  F.  This  experiment  clearly  shows  the  increased  concentra- 
tion due  to  the  maceration.  The  idea  of  combining  maceration 
with  percolation  was  apparently  favored  also  by  Squibb  for,  in 
^  This  Journal,  Vol.  50,  329,  (1878). 
2  This  Journal,  Vol.  50,  437,  (1878). 
