230  SYRUP  OF  SENEKA. 
and  its  solution  may  be  completed  in  a  few  minutes,  by  placing 
the  bottle  in  hot  water  and  shaking  occasionally.  Lastly,  add 
the  glycerin,  mix  well  and  strain  through  muslin. 
When  the  demand  for  the  syrup  is  urgent,  the  sugar  may  be 
dissolved  in  the  filtered  liquid  at  once,  by  means  of  a  moderate 
heat  in  an  open  vessel,  in  the  usual  way  of  forming  syrup,  ob- 
serving to  supply  the  loss  sustained  by  evaporation,  by  adding 
sufficient  water  through  the  strainer  to  make  the  finished  pro- 
duct, when  cold^  measure  one  pint. 
Particular  attention  must  be  paid  to  the  packing  of  the  powder 
in  the  percolator  to  insure  a  perfect  result,  as  this  is  one  of  the 
most  important  steps  of  the  process.  Its  performance  requires 
the  exercise  of  but  little  judgment  as  to  degree  of  compression) 
as  it  can  scarcely  be  packed  too  firmly.  It  is  best  packed  in 
small  portions  at  a  time,  in  strata  of  not  more  than  a  quarter  or 
half  inch  in  thickness,  and  should  be  compressed  so  firmly  that 
the  tincture,  when  it  begins  to  flow,  will  not  pass  at  a  faster  rate 
than  from  ten  to  fifteen  drops  per  minute,  which  will  increase  as 
the  exhaustion  advances. 
I  have  tried  prolonging  the  preliminary  maceration  to  twenty- 
four  and  even  thirty-six  hours,  and  after  frequent  trials  could 
perceive  but  little  if  any  difference  in  the  result.  Six  hours  give 
ample  time  for  the  powder  to  expand  and  its  fibres  to  become 
thoroughly  permeated  and  softened  by  the  menstrum,  which 
seems  to  be  all  that  is  requisite  for  the  complete  exhaustion  of 
its  medicinal  properties. 
If  the  process  is  managed  with  any  degree  of  care  and  skill 
the  exhaustion  of  the  drug  will  generally  be  found  complete  by 
the  time  a  pint  and  a  half  of  tincture  have  passed.  But  in  order 
to  guard  against  inexperience  and  unskillful  management,  I 
have  given  the  precautionary  direction  to  continue  the  percola- 
tion "  until  the  drug  is  exhausted." 
Notwithstanding  my  strong  predilections  and  conviction  in 
favor  of  a  finer  grade  of  powders  than  are  generally  recommended 
for  percolation,  I  have  varied  that  preference  in  this  instance, 
and  have  selected  for  the  preparation  of  this  syrup  a  much 
coarser  powder  than  is  directed  in  the  U.  S.  P.  for  the  same 
preparation.    My  reason  for  doing  this  is  to  avoid,  in  a  measure, 
