8 
Percolation. 
(  Am.  Jour.  Pharm. 
t     Jan.  1,  1872. 
eration  the  loss  of  these  medicinal  herbs,  sustained  by  drying.  The 
following  table  is  compiled  from  observations  by  me,  with  plants  or 
their  parts  of  my  own  collection,  and  I  regret  that  other  notes  of 
the  more  important  medicinal  herbs,  growing  in  this  locality,  are 
now  not  at  hand.  Sufficient  care  was  invariably  taken  to  collect  and 
weigh  the  plants  free  from  external  moisture  by  dew  or  rain ;  the 
drying  was  effected  under  an  airy  shed  or  in  a  room,  protected  from 
rain  ;  and  the  final  weight  was  taken  when  the  plants  ceased  to  lose 
weight  in  an  ordinarily  dry  atmosphere  : 
Loss,   yield,  air-dry. 
per  cent. 
per  cent 
Chimaphila  umbellata,  leaves  and  stem, 
.  48-98 
51  02 
Mentha  canadensis,  the  flowering  herb, 
.  89-21 
10-79 
Scutellaria  lateriflora,        "  " 
.  77-68 
22-32 
Lobelia  inflata,                 "  " 
.  76-56 
23-44 
Brunella  vulgaris,             "  " 
.  76-39 
23-61 
Nepeta  cataria,                 "  u 
.  76-39 
23-61 
Eupatorium  perfoliatum,  the  flowering  tops, 
.  76-52 
23-48 
G-naphalium  polycephalum,        "  u 
.  63-34 
36-66 
Hypericum  perforatum,            "  " 
.  61-03 
38-97 
Datura  stramonium,  the  leaves, 
88-70 
11-30 
Hepatica  triloba,        "      "  . 
.  71-65 
28-35 
Cassia  marilandica     "       "              .  . 
.  70-92 
29-08 
Leontodon  taraxacum,  the  root  collected  in  Oct., 
.  72-40 
27-60 
The  above  data  are  too  few  in  number  to  allow  of  any  general 
deductions ;  it  seems,  however,  as  if  low  plants  from  wet  localities 
(mentha  canad.)  and  juicy  leaves  (stramonium)  may  yield  air  dry 
residues,  equal  to  about  one-ninth,  plants  from  dry  sandy  soil 
(gnaphalium  and  hypericum)  about  one-third,  other  plants  about  one- 
fourth  or  one-fifth  of  their  original  weight ;  the  large  yield  of  chima- 
phila is  doubtless  in  the  main  due  to  the  woody  stems,  and  in  part 
also  to  the  leathery  leaves. 
NOTE  ON  PERCOLATION. 
By  Louis  S.  Cohen. 
The  most  efficient  instrument  for  all  preparations  which  require  to 
be  made  by  percolation,  is,  in  my  opinion,  the  ordinary  glass-funnel 
of  an  angle  of  about  59°,  as  the  following  results  of  an  experiment 
will  clearly  show  : 
