NEW  PROCESS  FOR  MAKING  FLUID  EXTRACTS.  83 
The  fluid  in  that  case  existing  naturally  in  the  substance ;  in 
this  case  it  has  to  be  added  in  the  shape  of  the  proper  solvent. 
This  solvent  is  added  part  at  a  time,  and  it  is  necessary  that  it 
should  be  so  regulated  in  strength,  alcoholically,  as  to  be  capable 
of  dissolving  out,  as  well  as  holding  in  solution,  all  the  medicinal 
substances  existing  in  the  crude  drug ;  it  is  believed  the  same 
strength  of  solvent  is  required  to  accomplish  both  objects.  The 
operation  is  a  simple  one,  but  requires  an  expensive  press  and 
considerable  skill  to  carry  it  out  properly.  The  drug  is  ground 
to  proper  fineness  in  such  a  manner  as  to  avoid  fine  dust  or  the 
necessity  of  sifting  out  fine  dust,  as  it  is  apt  to  contain  the  most 
valuable  parts  of  the  drug.  This  can  be  done  best  in  a  mill  of 
the  description  for  several  years  sold  by  me  to  the  trade,  and 
now  sold  by  Mr.  Charles  T.  Iredell,  of  Bristol,  Pa.  The  fineness 
must  necessarily  be  regulated  by  the  nature  of  the  substance — 
harsh  substances  can  be  ground  finer  than  those  of  a  soft  nature. 
After  being  ground,  the  drug  is  moistened  or  dampened  with 
part  of  the  solvent,  which  for  any  particular  lot  in  progress,  must 
always  be  of  same  strength.  After  being  allowed  to  stand  in  a 
closed  vessel  for  a  short  time,  it  is  submitted  to  a  powerful  pres- 
sure. This  operation  of  moistening  and  pressing  is  repeated 
several  times,  with  liquid  or  solvent  always  of  same  strength, 
until  the  same  amount  of  liquid  is  obtained  that  there  was  of  the 
drug  after  being  ground.  When  sufficient  liquid  is  obtained, 
nothing  further  is  necessary  but  to  mix  and  filter.  As  heat  and 
evaporation  and  long  exposure  to  atmospheric  air  are  all  avoided, 
and  if  the  moistening  and  pressing  are  properly  done  the  drug 
is  entirely  exhausted,  it  must  be  apparent  that  we  have  a  prepa- 
ration by  this  process  that  is  perfection  itself.  Its  superiority 
over  any  process  hitherto  known  must  be  apparent ;  as  in  avoid- 
ing heat,  we  avoid  the  changes  that  all  substances  are  subject  to 
by  cooking ;  in  avoiding  evaporation,  we  avoid  the  changes  in 
strength  of  solvent,  and  consequent  precipitation  of  substances 
more  or  less  valuable  ;  and  in  avoiding  exposure  to  atmospheric 
air,  we  avoid  all  chance  of  oxidation  and  evaporation  and  their 
consequences. 
On  examination  of  preparations  of  substances  of  a  fragrant 
nature  made  by  this  process — for  instance,  fluid  extracts  of 
