398     PREPARATIONS  OF  THE  U.  S.  PHARMACOPOEIA,  1860. 
conducted,  the  valerian  being  in  fine  powder,  nearly  all  of  the 
volatile  portion  of  the  root  is  included  in  the  first  liquid,  and 
there  is  no  impropriety  in  evaporating  the  second  liquid  by  dis- 
tillation so  as  to  recover  the  alcohol ;  but  this  cannot  be  done 
with  the  first  liquid,  which  in  this  case  should  be  concentrated  at 
near  the  ordinary  temperature. 
Fluid  Extracts. 
In  no  respect  is  the  Pharmacopoeia  more  changed  than  in  this 
chapter.  Formerly  five  fluid  extracts  and  two  oleo-resins,  called 
fluid  extracts,  were  found  in  it ;  now  twenty-five  of  these  prepa- 
rations are  recognized,  and  public  medical  opinion  goes  much 
further,  calling  for  a  number  of  them  not  at  present  authorized. 
Ext.  Buchu  Fluidum. — In  the  original  formula  for  this  prepa- 
ration, suggested  by  the  writer,  (see  Amer.  Jour.  Pharm.  vol.  xx. 
page  85),  the  strength  was  half  a  troy-ounce  to  the  fluid-ounce. 
In  the  authorized  formula  it  is  made  ounce  to  fluid-ounce.  The 
most  difficult  point  in  the  proper  conduction  of  this  process  is  to 
get  the  drug  in  powder  without  injury.  It  should  be  at  least  as 
fine  as  the  Pharmacopoeia  directs,  a  50  mesh  seive  powder ;  but 
there  is  no  objection,  rather  an  advantage,  in  having  it  finer, 
provided  the  volatile  ingredient  of  the  buchu  does  not  suffer,  loss 
in  getting  it  so.  Very  much  depends,  in  the  formulae  of  which 
this  is  a  type,  upon  the  slow,  regular,  and  thorough  solvent  ac- 
tion of  the  menstruum  in  obtaining  the  reserved  liquid,  in  this  in- 
stance twelve  fluid  ounces  in  bulk,  as,  independent  of  the  isola- 
tion of  nearly  all  of  the  valuable  constituents  which  are  thus  ex- 
empted from  subjection  to  the  heat  of  evaporation,  there  is  less 
need  of  pushing  the  percolation  so  far  by  which  a  less  proportion 
of  alcohol  will  be  required — a  point  of  great  importance  at  the 
present  juncture. 
Buchu  leaves  contain  much  mucilage,  which  is  excluded  from 
this  preparation,  it  not  being  deemed  of  any  medicinal  value,  as 
was  supposed  in  constructing  the  original  recipe. 
Ext.  Cimicifugce  Fluidum.  In  this  preparation,  owing  to  the 
large  proportion  of  resinoid  matter  it  contains,  the  formula  re- 
quires the  use  of  stronger  alcohol  to  the  extent  of  a  fluid  ounce 
