864 
The  Theory  of  Percolation. 
I  Am.  Tour.  I'hann. 
\     December,  b)2(). 
definite  amount  of  percolate  is  taken  and  this  is  used  to  moisten  the 
second  quantity  of  drug.  Tiie  remainder  of  the  percolate,  from  the 
first  portion  is  used  to  percolate  the  second  quantity  of  drug. 
A  definite  volume  of  percolate  from  this  second  percolation  is  re- 
served, the  next  fraction  of  percolate  used  to  moisten  the  third  lot 
of  drug,  and  the  rest  used  to  percolate  the  third  lot.  The  percolate 
from  the  third  quantity  of  drug  is  handled  exactly  as  that  fron  the 
Chart  K. 
first  and  second  lots  and  so  with  the  fourth  fraction  when  all  the  re- 
served portions  are  mixed  together  and  used  as  finished  fluidex- 
tract  the  weak  percolates  from  the  last  percolator  being  set  aside 
for  the  next  extraction  of  the  particular  drug. 
Chart  E.  presents  in  graphic  form  the  results  reported  by  Squibb 
in  the  repercolation  of  red  cinchona  by  his  first  process.    Four  por- 
