402     PREPARATIONS  OF  THE  U.  S.  PHARMACOPOEIA,  1860. 
simple  syrup,  requires  careful  attention  to  the  conditions  of  the 
recipe  as  regards  the  separation  of  all  the  alcohol. 
Ext.  Lupulince  Fluidum.  In  making  this  preparation,  the 
granular  character  of  the  powder  renders  it  too  porous  for  slow 
percolation,  and  it  is  requisite  to  close  the  neck  of  the  perco- 
later  by  means  of  a  cork  until  the  percolate  drops  but  slowly. 
In  this  way  nearly  the  whole  of  the  oleo-resin  may  be  secured 
in  the  first  liquid.  When  operating  on  a  large  scale  a  portion 
at  least  of  the  alcohol  may  be  recovered  from  the  second  liquid. 
When  carefully  made  from  good  material  this  fluid  extract  is 
well  marked  in  its  character,  being  strongly  odorous  of  the  lu- 
pulin,  and  fully  represents  it. 
Extract.  Pruni  Virginians.  This  preparation  has  been  al- 
ready so  fully  remarked  on  in  this  Journal  (vol.  iv.  pp.  22  and 
106,  and  more  recently  in  Proc.  Amer.  Pharm.  Assoc.,  1863, 
page  243),  that  it  is  unnecessary  to  dwell  upon  it.  The  chief 
points  of  attention  are  to  secure  genuine  wild  cherry  bark,  in 
fine  powder ;  to  percolate  slowly  ;  to  free  the  preparation  from 
alcohol  before  adding  the  almond  emulsion,  and  to  give  the 
latter  time  to  do  its  work.  In  making  a  quantity  of  this  ex- 
tract I  have  always  preferred  to  use  a  muslin  filter  in  a  large 
glass  funnel,  and  as  the  strong  liquid  ceases  to  be  visible  above, 
to  add  water  so  as  to  chase  out  the  absorbed  portion.  If  well 
made,  this  preparation,  mixed  with  water  without  precipitation 
in  all  proportions,  has  a  strong,  hydrocyanic  bitter  taste. 
Extr actum  Rhei  Fluidum. — This  formula  needs  to  be  modi- 
fied. The  fault  is,  the  presence  of  so  much  alcohol  as  to  cause 
the  crystallization,  and  precipitation  in  granular  form,  of  a 
large  portion  of  the  sugar.  In  the  formula,  as  originally  sug- 
gested by  the  writer,  this  fluid  extract  was  not  subject  to  this 
fault,  but  was  considered  too  thick  in  consiscence.  To  avoid 
this  difficulty  he  suggested  (Proc.  Amer.  Pharm.  Assoc.  1859, 
p.  274),  to  employ  alcohol  instead  of  diluted  alcohol,  so  as  to 
avoid  much  of  the  gummy  matter,  and  reduce  its  specific  grav- 
ity, reserving  the  first  liquid  for  spontaneous  evaporation  until 
free  from  alcohol.    It  was  no  doubt  the  intention  of  the  re- 
