PROPOSED  ECONOMY  OF  ALCOHOL  IN  PERCOLATION,  ETC.  123 
different  parcels  of  the  same  article.  The  first  five  ceroons, 
called  here,  for  convenience  in  designating  the  two,  the  "  Old 
Bark,"  was  coarsely  powdered  ;  that  is,  was  in  the  condition 
officinalfy  defined  as  "  moderately  fine  powder."  The  second 
lot,  or  "  New  Bark,"  was  powdered  very  finely,  or  as  it  is  com- 
monly sold  as  powdered  bark. 
*  The  officinal  quantity  of  sixteen  troyounces,  or  7680  grains, 
was  taken  for  each  percolation. 
Both  were  percolated  in  cylindrical  percolators  with  the  offici- 
nal dilated  alcohol,  but  moistened  with  different  proportions  of 
the  menstruum,  for  the  purpose  of  arriving  at  the  best  propor- 
tion. 
The  percolates  from  the  old  bark  deposited,  on  standing,  much 
more  cincho-tannates  and  cinchonic  red  than  the  new ;  and  the 
latter  made  a  perfectly  transparent  fluid  extract  either  with  the 
use  of  glycerine  or  sugar ;  whilst  the  former  would  do  so  with 
neither  of  these  under  any  management  that  could  be  adopted 
with  the  percolates  after  they  had  passed.    In  four  instances, 
the  percolation  was  carried  beyond  the  officinal  quantity,  and 
always  with  the  same  result,  of  obtaining  a  proportion  of  solid 
extract,  which  diminished  very  slowly  ;  so  that  the  point  of  ab- 
solute exhaustion  was  never  attained.    And  the  percolates  to 
the  very  last  gave  precipitates  with  solution  of  iodo-hydrargy- 
rate  of  potassium.    It  may  therefore  be  stated  that  here,  as  in 
the  case  of  colchicum  seed,  no  reasonable  continuation  of  the 
process  of  percolation  will  absolutely  exhaust  the  substance  of 
soluble  matters  or  of  the  alkaloids  ;  but  that  a  point  is  reached, 
and  that  always  far  short  of  that  indicated  in  the  officinal  for- 
mula, where  practical  exhaustion  is  easily  and  economically  at- 
tained.   It  is  quite  certain,  that  in  this  and  in  all  drugs,  a  large 
per  centage  of  the  extract  yielded  is  medicinally  inert  and  use- 
less ;  and  it  is  extremely  probable,  if  not  proven,  that  when  the 
menstruum  is  well  selected  and  well  adjusted  to  the  greatest 
solubility  of  the  medicinally  active  portion  of  the  extract,  that 
that  portion  is  more  easily  and  more  rapidly  washed  out  in  per- 
colation ;  and  hence,  that  the  quantity  of  the  active  principles 
in  each  successive  portion  of  the  percolate  diminishes  in  a  more 
rapid  ratio  than  that  of  the  whole  extract.    For  example,  cali- 
