AmMa°yU,r^7h8arm'}      Fluid  Extracts  by  Repercolation.  227 
Then  moisten  a  third  portion  of  8  parts  of  the  Cimicifuga  with  2 
parts  of  the  second  percolate  from  the  second  portion  of  the  Cimici- 
fuga, and  conduct  the  percolation  in  exactly  the  same  manner  as  in  the 
second  portion,  reserving  the  first  8  parts  of  percolate. 
Then  moisten  the  remaining  8  parts  of  the  Cimicifuga  for  a  fourth 
percolation,  and  conduct  it  in  exactly  the  same  manner  as  the  second 
and  third  portions. 
Mix  the  four  reserved  percolates,  weighing  30  parts,  and  set  it  by 
as  finished  Fluid  Fxtract  of  Cimicifuga  :  and  having  properly  labelled 
and  numbered  the  separate  portions  of  weak  percolate,  set  these  by 
until  the  process  for  making  this  preparation  is  to  be  resumed,  and  then 
use  them  exactly  as  in  the  second,  third  and  fourth  percolations,  reserv- 
ing 8  parts  of  the  first  percolate  from  each  8  parts  of  powder  as  the 
finished  fluid  extract,  ever  after,  and  setting  aside  the  weak  percolates 
from  each  operation  to  be  used  in  the  next  succeeding  one. 
In  applying  this  formula  and  process  each  part  was  represented  by  a 
troyounce,  and  therefore  the  percolations  were  made  with  8  troyounces 
of  powder  each.  For  the  purposes  of  this  trial  the  percolate  was  sepa- 
rated in  portions  of  about  2  troyounces  or  62  grams,  each  instead  of  4 
troyounces  as  indicated  in  the  process,  and  each  separate  portion  was 
carefully  weighed.  A  cubic  centimetre  of  each  portion  of  percolate 
was  carefully  weighed  on  a  flat  watch-glass,  and  then  dried  and  the  dry 
extract  weighed.  Then  a  proportion  was  made  by  calculation  from 
these  data  to  find  the  total  dry  extract  in  each  portion  of  the  percolate, 
this  proportion  being  as  follows  :  As  the  weight  of  the  cc.  of  percolate 
is  to  the  weight  of  dry  extract  which  it  yielded,  so  is  the  whole  por- 
tion of  the  percolate  to  the  dry  extract  it  contains.  Having  thus 
obtained  the  total  dry  extract  contained  in  each  portion  of  percolate, 
the  sum  of  these  would  be  the  total  extract  of  all  the  portions.  But  as 
these  portions  varied  in  weight  the  series  would  not  represent  the  rate 
of  exhaustion.  Therefore  another  proportion  was  made  to  show  the 
rate  or  progress  of  exhaustion  by  the  percentage  of  dry  extract  con- 
tained in  each  portion  of  percolate.  The  formula  for  this  proportion 
is  as  follows  :  As  the  weight  of  the  portion  of  percolate  is  to  the  weight 
of  extract  which  it  contains,  so  is  100  to  the  percentage  of  the  dry 
extract  contained  in  the  portion  of  percolate.  The  difference  of  specific 
gravity  between  the  menstruum  and  the  percolate,  which  also  shows 
the  rate  of  exhaustion  was  obtained  by  a  small  s.  g.  flask. 
