4  ECONOMY  IN  THE  USE  OP  ALCOHOL  IN  PERCOLATION. 
portions  of  percolate,  the  determinations  were  more  difficult  and 
less  accurate,  and  the  results  were  therefore  less  reliable ;  and 
beside,  the  extractive  matter  there  is  well  known  to  be  useful, 
and  not  inert.  This  decisive  confirmation  of  the  general  results 
obtained  with  the  cinchonas  is  important,  and  as  far  as  Cinchona 
and  Podophyllum  may  be  safely  accepted  as  types  or  representa- 
tives of  classes  of  drugs,  the  results  may  be  considered  as 
established  for  percolation  in  general.  It  is  a  remarkable  cir- 
cumstance, and  very  instructive  in  relation  to  percolation  in 
general,  that  with  powders  of  the  same  degree  of  fineness,  taken 
in  the  same  quantities,  managed  in  the  same  way  by  the  same 
hands  in  the  same  apparatus,  and  with  the  same  menstruum, 
Cinchona  requires  four  times  as  much  menstruum  and  four  times 
as  much  time  as  Podophyllum  to  attain  the  same  degree  of 
practical  exhaustion.  In  this  respect,  as  well  as  in  others,  it  is 
interesting  to  compare  the  tables  given  of  the  percolates  of  the 
two  substances. 
The  pair  of  percolations,  given  in  the  table  on  page  5,  are  se- 
lected from  three  which  compose  this  series,  as  being  very  success- 
ful and  accurate,  and  well  sustained  by  others  which  preceded 
them.  The  same  powder,  percolater,  menstruum  and  manage- 
ment was  used  with  both,  as  well  as  the  same  measuring  flasks, 
etc.,  and  pains  was  taken  to  avoid  all  sources  of  error  which 
previous  experience  had  detected,  and  the  drying  before  a  final 
weighing,  which  is  a  fruitful  source  of  error  in  all  such  research- 
es, w^s  continued  for  ten  days.  The  table,  it  is  hoped,  will 
sufficiently  explain  itself,  but  the  attempt  to  distinguish,  in  a 
column  of  remarks,  the  difference  in  the  appearance  of  the  differ- 
ent portions  of  resin  and  extract,  is  unsuccessful,  except  in 
showing  that  there  was  a  marked  difference. 
The  difference  in  the  successive  portions  of  resin  precipitated 
was  not  in  appearance  only,  but  also  in  physiological  effect  when 
taken.  It  having  been  first  proved  that  one-fourth  of  a  grain  of 
the  resin  as  obtained  altogether,  by  a  previous  process,  when 
taken  at  a  definite  hour  of  the  evening,  with  due  regard  to  condi- 
tion, diet,  exercise,  etc.,  would  produce  a  distinct  aperient  or  lax- 
ative effect  on  the  following  morning,  the  filter  containing  the 
