FORMULA  FOR  THE  FLUID  EXTRACTS. 
531 
bulk,  of  an  ounce  to  the  fluid  ounce,  except  in  the  oleoresins,  in 
the  way  least  calculated  to  injure  their  medicinal  virtues  and 
sensible  qualities,  leaving  the  resulting  menstruum  appropriate 
for  retaining  the  active  matter  in  solution. 
As  regards  the  means  for  their  preservation  from  decomposi- 
tion, alcohol  and  sugar  have  been  employed,  as  the  cases  de- 
manded, and  in  a  few  instances  acetic  acid  is  added  for  special 
reasons.  The  process  of  percolation  has  been  almost  invariably 
used,  as  best  adapted  to  effect  the  desired  objects,  and  the 
formulae,  both  in  manipulation  and  quantities,  are  based  on  the 
supposition  that  they  are  to  be  carried  out  in  the  shop  or  labora- 
tory of  the  apothecary,  and  not  on  the  large  scale  by  the  manu- 
facturer. 
Where  alcohol  has  been  used  as  the  agent  for  preservation,  it 
has  been  employed  in  the  form  of  the  first  dense  solution  ob- 
tained in  the  percolation,  regulating  the  quantity  reserved  for 
this  purpose  by  the  quantity  of  alcohol  to  be  retained  in  the  fluid 
extract,  and  evaporating  the  weaker  liquors  till  reduced  to  a  bulk 
sufficient  to  make  up  the  required  measure  by  an  indirect  heat 
of  about  150°  F.  in  an  open  vessel. 
When  sugar  has  been  employed  as  the  preservative  agent,  it 
is  added  to  the  percolate  before  the  completion  of  the  evapora- 
tion, so  as  to  take  advantage  of  the  well  ascertained  solvent 
power  of  sugar  in  regard  to  resinous  and  apothemic  matter. 
A  new  class  of  oleoresinous  fluid  extracts  has  been  suggested, 
in  which  the  stronger  aromatics  have  been  introduced,  such  as 
cloves,  cinnamon,  cardamom,  &c,  and  which  possess,  for  certain 
uses,  very  desirable  advantages  from  their  concentration. 
The  number  of  oleoresins  has  been  considerably  increased  on 
the  ground  that  they  represent  their  respective  sources  more 
completely,  and  in  smaller  bulks  than  any  other  form  of  fluid  or 
semifluid  extracts.  For  this  reason  also  it  is  insisted  that  they 
should  occupy  a  distinct  position  under  the  name  of  4 'Oleore- 
sins," and  thus  avoid  the  necessity  of  making  a  discrepancy 
in  the  proportional  strength  of  all  those  preparations  which  go 
by  the  name  of  fluid  extracts. 
In  bringing  forward  so  large  a  number  of  fluid  extracts,  it  is 
not  intended  to  recommend  that  all  of  them  should  be  introduced 
into  the  Pharmacopoeia,  but  to  afford  sufficient  scope  in  the 
