Am May^t"11, }     Fluid  Extracts  by  Reper  eolation.  22$ 
not  exceed  the  weight  of  the  powder  ;  nor  need  the  rate  be  slower 
than  to  obtain  the  weight  of  the  powder  in  48  hours,  although  as  a 
general  rule  the  slower  the  rate  the  better  the  results.  After  the 
reserved  portion  the  rate  may  be  increased  gradually  so  that  the  last 
portion  be  received  in  about  6  hours.  The  separate  portions  of  weak 
percolate  should  not  exceed  the  weight  of  the  powder. 
Eighth,  that  a  good  practical  exhaustion  requires, — as  a  general  rule, 
— for  the  first  percolation,  with  fresh  menstruum,  that  the  total  perco- 
lates should  weigh  3*5  times  the  weight  of  the  powder.  That  for  the 
second  percolation  or  first  repercolation,  the  weight  should  be  4*5  times 
that  of  the  powder.  And  for  all  subsequent  repercolations  the  weight 
should  be  5,  6  or  7  times  that  of  the  powder,  according  to  the  nature  of 
the  substance  percolated,  and  the  skill  and  care  with  which  the  process 
is  managed. 
Ninth,  that  the  relation  of  weight  for  weight,  instead  of  minim  for 
grain,  should  be  established  under  proper  controlling  conditions.  But 
that  unless  properly  guarded  in  the  quality  and  moisture  of  the  drug 
used,  the  new  relation  is  liable  to  be  even  more  inaccuate  than  the  old, 
because,  the  poorer  the  quality  of  the  drug  the  less  dense  will  be  the 
percolates,  and  the  greater  will  be  the  volume  for  the  prescribed 
weight,  and  this  involves  the  serious  difficulty  that  when  the  fluid 
extract  is  made  by  weight  but  administered  by  measure,  the  poorer  the 
drug  from  which  it  was  made  the  smaller,  as  well  as  the  weaker,  the 
dose  will  be. 
Tenth,  that  some  good  practical  method  of  comparing  fluid  extracts 
by  a  standard  is  very  much  needed ;  and  that  for  such  drugs  as 
Cinchona,  a  method  of  arithmetical  dilution  would  be  easy  and  prac- 
tical if  well  worked  out. 
Whilst  the  above-mentioned  work  on  Cinchona  was  in  progress  a 
paper  by  Mr.  J.  U.  Lloyd  of  Cincinnati  appeared  in  the  "Am.  Jour. 
Phar.,,  for  1878,  p.  1,  upon  Fluid  Extract  of  Cimicifuga.  This  paper 
contains  so  many  valuable  observations  made  without  bias,  and  with 
such  care  and  labor  as  at  once  to  command  attention.  The  results 
however  were  in  many  important  respects  so  at  variance  with  those  of 
the  previous  experience  of  this  writer  as  to  force  upon  him  the  con- 
clusion that  Mr.  Lloyd  might  have  misinterpreted  some  of  his  obser- 
vations ;  and  if  so  it  was  important  that  his  work  should  be  gone  over 
in  the  light  of  the  many  useful  suggestions  it  contains  for  those  who* 
J5 
