Am.  .Tour   PI  1  arm. 
May,  1884. 
Tincture  of  Hyoscyamus. 
289 
prepared  duplicate  tinctures  with  rectified  spirit  of  every  sample  of 
henbane  on  the  table,  and  two  things  cannot  fail  at  once  to  strike  even 
an  ordinary  observer  regarding  them,  namely,  first,  the  close  resem- 
blance which  they  all  (annual  and  biennial)  bear  to  each  other,  and, 
second,  the  striking  unlikeness  which  they  have  to  a  tincture  prepared 
from  proof  spirit.  They  have  all  the  same  deep  green  coloration,  not 
unlike  essence  of  bergamot,  or  better  still,  like  commercial  cajeput  oil, 
and  this  characteristic  feature,  so  striking  in  the  first  instance,  is  equally 
remarkable  for  its  evanescence  on  exposure.  I  find  that  even  twelve 
hours  exposure  will  quite  change  their  appearance,  and  this  change 
goes  on  so  rapidly  that  towards  the  end  of  a  week  the  tincture  becomes 
almost  decolorized.  I  have  here  two  tinctures  thus  exposed,  which  you 
can  compare  with  samples  of  the  same  tincture  carefully  preserved. 
Twelve  hours'  exposure  removed  every  trace  of  bright  green,  convert- 
ing the  tincture  into  a  brown  olive,  and  this  in  turn  gradually  faded, 
until  it  reached  on  the  seventh  day  the  dirty  straw  white  which  you 
now  see.  This  you  will  admit  is  of  itself  a  very  serious  objection  to 
any  change  in  the  spirit  strength  of  the  tincture,  more  especially  if  we 
keep  in  mind,  comparatively  speaking,  the  permanent  character  (to  the 
naked  eye)  of  the  official  tincture,  three  weeks'  exposure  under  similar 
conditions  making  scarcely  any  observable  difference  in  it. 
There  is  still  one  more  objection  to  changing  the  spirit  strength  of 
this  tincture,  and  to  my  mind  it  is  the  most  serious  of  all,  namely,  that 
the  stronger  spirit  does  not  exhaust  the  leaves  of  their  active  principle. 
In  saying  this  I  know  that  I  am  going  not  only  in  the  face  of  Mr. 
Gerrard,  but  also  of  such  an  eminent  authority  as  Christison,  who  says 
that  the  leaves  impart  their  active  principle  alike  to  alcohol  and  proof 
spirit.  From  the  very  great  change  which  lias  taken  place  in  the  recti- 
fied spirit  tincture  on  exposure,  as  well  as  from  the  entire  absence  of 
any  coloring  principle  except  the  chlorophyll  when  treated  with  ben- 
zole as  already  described  (on  agitating  the  rectified  spirit  tincture  with 
water  and  benzole,  the  benzole  extracts  every  particle  of  green  coloring 
matter  and  leaves  the  tincture  beneath  absolutely  colorless),  I  think 
there  is  every  reason  to  conclude  that  the  stronger  alcohol  exhausts  the 
leaves  to  a  very  great  extent  of  their  green  coloring  matter  and  not  to 
any  extent  of  their  active  principle.  In  further  proof  of  this  I  have 
to  point  out  that  with  wonderful  uniformity  all  the  proof  spirit  tinc- 
tures contain  from  five  to  six  times  the  amount  of  extractive  matter 
19 
