•on  fractional  percolation. 
343 
appropriate  menstruse  as  to  render  them  equally  acceptable  in 
more  bulky  doses.  By  adopting  this  strength  a  great  number 
of  substances  could  be  made  available  in  a  concentrated  form, 
which  are  now  excluded  on  account  of  the  deleterious  effects  of 
lieat. 
On  looking  over  the  formulae  for  the  fluid  extracts  of  our 
Pharmacopoeia  it  will  be  observed  that  in  no  instance  (except 
perhaps  fluid  extract  of  ipecac)  more  than  four  fluidounces  of 
percolate  is  directed  to  be  obtained  from  one  troyounce  of  drug. 
Taking  this  for  a  basis,  I  have  framed  the  following  general 
formula  : 
Take  of  the  drug  (in  a  powder  of  the  requisite  fineness,)  16 
troyounces ; 
Of  the  menstruum,  a  sufficiency. 
Divide  the  powder  into  portions  of  eight,  five  and  three  ounces  ; 
moisten  i\ie  first  portion  (of  eight  ounces)  with  three  fluid  ounces 
of  the  menstruum,  pack  it  carefully  in  a  conical  displacer,  cover 
the  surface  with  a  disk  of  filtering  paper,  and  pour  on  men- 
struum as  required,  observing  that  the  surface  always  remains 
covered  with  it.  Reserve  the  percolate,  as  it  passes,  in  the 
following  fractional  portions  : 
First  fraction —  8  fluidounces — Reserve  A. 
Second     "       6  "        Percolate  No;  1  A. 
Third      "     14  "  "        "    2  A. 
Fourth  4  "  "         "    3  A. 
Proceed  to  moisten  the  second  portion  (of  five  ounces)  with  2|- 
fluidounces  of  percolate  No.  1  pack  as  above  and  pour  on 
successively  the  remainder  of  percolate  No.  1  JL,  followed  by 
percolates  Nos.  2  A  and  3  A,  and  sufficient  additional  men- 
struum to  produce  the  following  fractions  of  percolate  : 
First  fraction —  6  fluidounces — Reserve  B. 
Second    "        4       "  Percolate  No.  1  B. 
Third      "       10       "  "       ^"  2B. 
Fourth    "        4       "  "        "  3B. 
Then  moisten  the  third  portion  (of  three  ounces)  with  1 J  fluid- 
ounces  oi  percolate  No.  1  pack  as  above,  and  percolate  with 
the  percolates      and  additional  menstruum,  in  the  same  succes- 
