82  Extracts  containing  Chlorophyll      { A $fg* 
EXTRACT  OF  HENBANE. 
Quantity  Amount  of  ChlorophylL 
Samples.                         employed.  obtained. 
No.  1       .        .        100  grains       .  .        16  grains. 
No.  2  .        100  grains        .  .        11*5  grains. 
No.  3       .       .        100  grains       .  .        18*5  grains. 
No.  4       .        .        100  grains       .  .        14  grains. 
The  consistence  of  the  samples  was  good. 
EXTRACT  OF  WILD  LETTUCE. 
Quantity  Amount  of  Chlorophyll 
Samples.  employed.  obtained. 
No.  1        .        .        100  grains       .        .        13  grains. 
No.  2        .        .       100  grains       .        .  1  grain. 
No.  3        .        .        100  grains       .        .  1  grain. 
No.  4       .        .        100  grains       .        .  9*5  grains. 
Nos.  1  and  4  were  tolerably  firm,  but  Nos.  2  and  3  were  of  the 
consistence  of  thick  treacle. 
In  these  experiments,  excepting  Nos.  2  and  3  of  extract  of  aconite, 
the  coloring  matter  was  separated  by  dissolving  the  extracts  in  hot 
distilled  water ;  transferred  to  tared  filters,  they  were  washed  with 
warm  distilled  water  until  the  latter  passed  through  colorless  ;  the 
chlorophyll  was  then  dried  in  an  air  bath  at  100  C,  until  the  weight 
became  constant.  The  insoluble  matter  in  some  samples  of  extracts 
of  aconite  and  lettuce  was  very  small,  amounting  to  only  one  and  one 
and  a  half  per  cent.,  and  in  extract  of  lettuce  was  not  green  but 
brown ;  whether  this  change  is  due  to  age  or  not  I  am  unable  to  say. 
From  these  varying  results  it  is  clear  that  extracts  containing  the 
coloring  matter  are  not  of  anything  like  uniform  strength  ;  so  much 
so  is  it  the  case  that  I  venture  to  bring  the  subject  before  the  Society 
in  the  hope  that  discussion  will  elicit  opinion  as  to  the  desirability  or 
otherwise  of  eliminating  this  cause  of  varying  strength  in  prepara- 
tions, which  it  is  so  very  desirable  should  be  of  constant  and  unvary- 
ing strength. 
Dr.  Harley*  has  shown  how  valueless  the  extract  of  hemlock  of  the 
Pharmacopoeia  is,  and  the  value  he  attaches  to  the  preserved  juice. 
It  is  evident  from  his  experiments  that  the  prolonged  application  of 
heat  employed  to  evaporate  the  juice  to  the  consistence  of  an  extract, 
dissipates  so  much  of  the  active  principle,  conia,  that  very  little  of  it 
*  On  the  Preparation  of  Extract  of  Oonium  of  the  British  Pharmacopoeia, 
1864  and  1867,"  Pharm.  Journ.,  Yol.  VIII,  1866-67.  Amer.  Journ.  Pharm., 
1867,  266,  &c. 
