22  The  Strength  of  Fluid  Extracts.      { mT' 
dent  therefore  that  the  Pharmacopoeia  should  direct  a  little  too  much 
menstruum  in  some  instances  than  not  enough  in  others. 
Extractum  CincJionce  Fluidum. 
Take  of  Cinchona,  yellow,  sixteen  troy  ounces. 
Alcohol,  four  pints. 
Glycerin,  eight  fluid  ounces. 
Grind  and  sift  the  cinchona  in  the  same  manner  as  directed  for 
buchu,  mix  the  glycerin  with  three  pints  of  the  alcohol,  and  with  six 
fluid  ounces  of  this  menstruum  moisten  the  cinchona,  and  pack  mod- 
erately in  a  glass  percolator  ;  pour  on  the  balance  of  the  alcohol  and 
glycerin,  and  then  the  remaining  pint  of  alcohol,  following  it  with 
water,  till  about  four  pints  of  percolate  have  been  obtained.    Put  the 
percolate  into  a  water-bath  still  and  distill  ofi"  the  alcohol  till  reduced 
to  the  measure  of  sixteen  fluid  ounces.    This  is  essentially  the  formula 
recommended  by  Dr.  Squibb  (Araer.  Jour.  Phar.,  vol.  39,  page  515), 
differing  only  in  this,  that  the  glycerin  forms  part  of  the  menstruum 
— thus  securing  its  solvent  as  well  as  its  preservative  influence,  and 
also  reducing,  to  the  extent  of  the  quantity  of  glycerin  present,  the 
amount  of  evaporation  necessary.    With  the  glycerin  diluted  to  the 
extent  it  is  in  this  formula  the  percolation  is  not  too  tedious. 
Fxtractum  Hyoscyami  Fluidum. 
Take  of  Henbane  Leaf,  sixteen  troy  ounces. 
Glycerin,  four  fluid  ounces. 
Alcohol  and  Water,  each  a  sufiicient  quantity. 
Mix  the  glycerin  with  twelve  fluid  ounces  of  alcohol  and  eight  fluid 
ounces  of  water,  and  with  six  fluid  ounces  of  this  menstruum  moisten 
the  henbane  previously  prepared  for  percolation.    Pack  firmly  in  a 
cylindrical  glass  percolator,  and  pour  on  menstruum  till  the  surface 
remains  covered  ;  macerate  for  twenty-four  hours,  then  proceed  with 
the  percolation,  using  the  remainder  of  the  glycerin  menstruum,  dilute 
alcohol  and  water  successively  till  at  least  three  pints  of  percolate 
have  been  obtained.    Of  this  reserve  the  first  twelve  fluid  ounces,  and 
distill  the  remainder  in  a  water-bath  still  till  reduced  to  eight  fluid 
ounces ;  to  this  add  the  reserve  percolate,  and  continue  the  distillation 
till  reduced  to  such  a  point  that,  when  cold,  the  finished  fluid  extract 
shall  measure  exactly  sixteen  fluid  ounces. 
In  the  same  way  prepare  fluid  extract  of  senna,  uva  ursi,  spigelia, 
sarsaparilla,  dulcamara,  serpentaria,  taraxacum,  and  gentian. 
