554 
Process  of  Percolation. 
/  Am.  Jour.  Pharm. 
t     Dec.  1,  1874. 
even  when  deemed  necessary  in  the  case  of  substances  that  are  tough- 
est, most  impenetrable  and  compact  in  texture,  such  as  nux  vomica 
and  other  similar  substances,  while  in  the  great  majority  of  cases 
from  eight  to  twelve  hours  will  suffice.  This  will  give  ample  time,  as 
I  have  remarked  in  a  former  paper  (Art.  Syrup  Senega,  Am.  Journ. 
Pharm.,  May,  1870),  "for  the  powder  to  expand  and  its  fibres  to 
become  thoroughly  permeated  and  softened  by  the  menstruum,''  and 
also  for  the  solvent  power  of  the  menstruum  to  become  exhausted, 
which  is  all  that  is  requisite. 
It  must  be  remembered,  too,  that  the  manufacture  of  fluid  extracts 
in  drug  stores  is  not  an  every-day  operation ;  it  is  therefore  impos- 
sible for  the  pharmacist  to  make  himself  familiar  with,  and  to  remem- 
ber from  time  to  time,  the  amount  of  pressure  required  for  properly 
packing  the  various  kinds  of  drugs  ;  so  that  even  the  most  skilful 
operator  will  occasionally  make  a  mistake,  and  get  his  powder  either 
too  tightly  or  too  loosely  packed.  In  the  former  case,  only  a  too 
tardy  percolation  may  be  the  result,  while  in  the  latter  an  imperfect 
and  unsatisfactory  result  is  attained,  a  circumstance  to  be  greatly 
deprecated  ;  and  in  the  new  process  there  is  no  provision  made  to  rem- 
edy or  to  compensate  for  such  a  defect  or  failure. 
If  the  officinal  process  for  percolation  is  so  economical  and  men- 
struum-saving, why  do  not  our  large  wholesale  manufacturers  of  fluid 
extracts  adopt  it  ?  for,  certainly,  if  there  is  any  class  of  manufactur- 
ers who  would  be  likely  to  seek  for  and  adopt  any  economical  pro- 
cess, that  would  yield  good  and  reliable  preparations,  it  would  be  the 
wholesale  manufacturers.  But,  upon  inquiry  among  our  largest  and 
most  reputable  manufacturers  of  this  class  of  products,  in  this  city, 
I  find  that  none  of  them  have  adopted,  in  their  establishments,  the 
officinal  process  for  fluid  extracts.  These  gentlemen  have  too  much 
at  stake  to  rely  upon  any  untrustworthy  or  uncertain  process  in  the 
manufacture  of  their  products. 
Another  very  objectionable  feature  attending  the  long  maceration 
in  funnels  or  other  percolators,  directed  in  the  officinal  process,  is 
the  constant  liability  to  loss  of  menstruum  by  evaporation  during  this 
long  period  of  repose,  and  especially  is  this  apt  to  be  the  case  in  hot 
weather,  if  a  strongly  alcoholic  menstruum  be  used,  as  the  subtle 
vapor  of  this  fluid  is  hard  to  imprison.  I  have  found  India  rubber 
cloth,  when  tightly  secured  over  the  top  of  the  percolator,  both  con- 
venient and  useful  for  the  purpose,  but  even  this  will  sometimes  per- 
