342 
ON  FRACTIONAL  PERCOLATION. 
solid  extract  by  the  officinal  process  than  by  fractional  perco- 
lation, is  owing  to  the  fact  that  alcohol  is  used  in  the  former, 
previous  to  the  use  of  diluted  alcohol,  while  in  the  latter,  diluted 
alcohol  alone  was  used.  Had  alcohol  been  used  in  fractional 
percolation  previous  to  diluted  alcohol,  there  is  scarcely  a  doubt 
that  the  result  would  have  been  more  favorable  to  fractional  per- 
colation ;  as  the  previous  percolation  with  alcohol  appears  to 
enable  the  diluted  alcohol  to  exercise  its  solvent  power  more 
adily. 
With  but  limited  experience  in  the  matter,  I  feel  confident 
that  almost  all  drugs  can  be  exhausted  by  the  process  of  frac- 
tional percolation,  "  if  the  proper  menstruum  is  selected  ;  if  the 
drug  is  properly  comminuted ;  and  if  the  operator  possesses  the 
necessary  skill."  The  operator  must  be  competent  to  judge  of 
the  proper  fineness  of  the  powder,  and  whether  the  same  must 
be  packed  loose,  or  compact,  or  moderately  compact.  The  pro- 
cess does  not  admit  of  failure  during  any  of  its  stages,  and  re- 
quires the  utmost  care  and  observance  of  minutiae  and  detail, 
when  applied  to  the  preparation  of  fluid  extracts  of  the  present 
strength.  A  very  limited  amount  of  menstruum  must  be  used, 
and  we,  therefore,  possess  no  margin  to  make  up  for  any  neg- 
lect or  failure  during  any  part  of  the  process.  But  if  we  could 
use  powders,  as  prescribed  by  the  Pharmacopoeia,  for  fluid  ex- 
tracts, and  were  unable  to  use  for  each  fraction  of  powder  as 
large  a  proportion  (or  more)  of  menstruum  as  is  at  present  di- 
rected for  these  preparations,  the  process  could  be  made  uni- 
versally applicable,  with  scarcely  a  chance  for  failure  in  the 
hands  of  even  the  moderately  skilled. 
This  is  'possible  if  we  reduce  the  strength  of  fluid  extracts 
so  that  eight  troyounces  of  drug  shall  be  represented  by  one 
pint,  and  I  see  no  good  reason  why  this  should  not  be  done  !  We 
have  the  precedent  in  the  fluid  extract  of  cinchona  and  wild 
cherry  baric,  both  of  which  are  made  of  the  above  strength,  and 
are  yet  sufficiently  strong  for  all  practical  purposes.  And  is 
there  any  real  necessity  for  the  extreme  concentration  of  this 
class  of  preparations  ?  With  but  few  exceptions,  they  are  ad- 
ministered in  doses  of  a  fluiddrachm  or  less,  and  those  that  are 
given  in  larger  doses  could  perhaps  be  so  modified  by  the  use  oi 
