ON  FRACTIONAL  PERCOLATION. 
339 
three  hours  the  percolate  began  to  pass  at  the  rate  of  thirty  drops  to  the 
minute,  and  gradually  faster,  until  towards  the  end  of  the  process  it 
passed  at  the  rate  of  about  eighty  drops  to  the  minute.  The  percolate 
was  collected  in  the  following  fractions  : 
First  fraction — 7*5  f.  ounces — designated  Reserve  A. 
Second    "       6*        *'  "       Percolate  No.  1  A. 
Third      "      10-5       "  "  "  "    2  A, 
Fourth    *'      31-        "  "        Exhaust  percolate  A. 
The  second  portion  (of  eight  ounces)  was  moistened  with  part  of  percolate 
No.  1  A,  packed  as  above,  the  remainder  of  the  percolate  poured  on,  and 
as  soon  as  absorbed,  followed  by  percolate  No.  2  A,  and  this  by  diluted 
alcohol.    The  percolate  was  collected  in  the  following  fractious  : 
First  fraction — 6  f.  ounces — designated  Reserve  B. 
Second  4         "  Percolate  No.  1  B, 
.     Third  €-5       "  "  2  B, 
Fourth  27.  "        Exhaust  percolate  B. 
The  third  portion  (of  six  ounces)  was  now  treated  with  percolates  No.  1 
B,  and  No.  2  B,  and  diluted  alcohol  in  the  same  manaer  as  the  second 
portion,  and  the  percolates  collected  in  the  following  fractions  :  _ 
First  fraction — 10'5  f.  ounces — designated  Reserve  0. 
Second    "       22*  "        Exhaust  percolate  C. 
The  reserve  portions  A,  B  and  0  were  now  mixed  in  an  accurately  tared 
flask,  and  after  ascertaining  the  weight  of  the  finished  fluid  extract,  a 
fractional  portion  was  evaporated  as  near  to  dryness  as  possible,  in  order 
to  determine  the  amount  of  solid  matter  contained.  The  exhaust  perco- 
lates A,  B  and  C  were  also  mixed  and  a  fractional  portion  evaporated  to 
dryness.    The  following  is  the  result: 
Amount  of  solid  extract — 
lo  24  f.  ounces  of  fluid  extract  2,B80  grains. 
In  1  f.  ounce        "        "  120  grains. 
In  exhaust  percolates  for  24  f.  ounces  of  fluid 
extract  432  grains. 
In  exhaust  percolates  for  1  f.  ounce  of  fluid  extract  18  grains. 
From  1  troy  ounce  of  Alexander  senna,  .  138  grains. 
Experiment  2. — Twenty-four  troyounces  of  the  same  lot  of  powdered 
Alexandria  senna  were  exhaasted  according  to  the  Pharmacopceia  direc- 
tions and  three  percolates  obtained,  as  follows  : 
First  fraction —  24  f.  ounces — designated  Reserve, 
Second    *'       48       "  "       Additional  percolate. 
Third      "      105  "  Exhaust 
Fractional  portions  of  each  of  these  percolates  were  evaporated  with  the 
following  results : 
Amount  of  solid  extract — 
In  reserve  for  24  f,  ounces  of  fluid  extract       2,304  grains. 
