Am.  Jour.  Pharm. 
March,  1888. 
Percolation  of  Buchu  Leaves. 
137 
PERCOLATION  OF  BUCHU  LEAVES. 
Editor  American  Journal  of  Pharmacy  : 
In  reading  the  minutes  of  the  Pharmaceutical  Meetings  in  the  Jan- 
uary and  February  numbers  of  the  Journal,  I  noticed  the  remarks 
about  fluid  extracts  and  the  exhaustion  of  buchu  particularly.  I 
Avas  at  the  time  engaged  in  making  fluid  extract  of  buchu  by  re-per- 
colation, and  had  determined  the  amount  of  extraction  in  each  por- 
tion of  the  third,  fourth,  fifth  and  sixth  percolates,  operating  in  each 
case  on  473  grams  of  drug,  and  using  the  oflicinal  menstruum.  Re- 
cently I  exhausted  100  grams  by  simple  percolation  to  ascertain  the 
total  amount  of  extraction,  which  was  23.9  per  cent.,  and  also  the 
amount  in  each  100  c.c.  of  percolate,  which  is  given  in  the  following 
table,  as  well  as  the  results  of  re-percolation,  reduced  to  percentage  for 
comparison. 
Percola- 
tion. 
By  Re-percolation. 
Sii  o 
^  s  s 
o 
o  o  S  M 
a>  .  GO 
>li  oQ 
1st.  Portion. 
2d. 
3d. 
4th.  " 
5th.  " 
6th. 
7th. 
19.1  per  ct 
3.25 
0.95  " 
0.30 
0.20  " 
0.10 
18.38pr  ct 
5.60  " 
1.72  " 
1.03  " 
0.45  " 
0.22 
19.87pr  ct 
6.39  " 
2.26  " 
1.42  " 
0.93  " 
0.39  " 
21.29pr  ct 
5.99 
2.06  " 
1.57 
1.51 
0.83  " 
0.44 
20  25pr  ct 
5.79  " 
2.16  " 
1.34  " 
1.25 
0.98  " 
0.56  " 
Total  extract  per  ct.  of  drug. 
Eeserved  extract. 
Extract  carried  forward. 
Actual  extract  obtained. 
23.90  " 
19.10  " 
4.80  " 
27.40  " 
18.38  " 
9.02  " 
22.60  " 
31.26  " 
19.87  " 
11.39 
22.24  " 
33.69  " 
21-29  " 
12.40  " 
22.30  " 
.32.33 
20.25  " 
12.08 
19.93  " 
In  the  re-percolation  the  portions  of  percolate  were  473  c.c.  each. 
In  the  third,  fourth  and  sixth  percolations  tall  cylindrical  percola- 
tors  were  used.  In  the  fifth  percolation  an  ordinary  percolator  was 
used,  and  when  packed  the  drug  was  only  about  one-half  as  high  as 
that  in  the  tall  ones,  but  it  yielded  much  better  results,  giving  a  larger 
amount  of  extraction  in  the  first,  and  less  in  the  succeeding  portions ; 
showing  that  the  extraction  was  somewhat  retarded  by  the  longer  col- 
umn of  drug  it  had  to  pass  through  in  the  tall  ones. 
In  each  case  the  rate  of  percolation  was  about  the  same,  being  regu- 
lated by  a  rubber  tube  and  adjustment  of  the  height  of  the  receiver. 
