ON  A  TEST  FOR  THE  RESIN  OF  CANNABIS  INDICA.  25 
Messrs.  T.  and  H.  Smith,  of  Edinburgh,  who  have  studied 
hemp  resin  closely,  have  preferred  to  treat  the  gunjah  first  with 
water,  and  then  with  solution  of  carbonate  of  soda,  to  remove  in- 
ert matter  soluble  in  these  menstrua,  after  which  the  hemp  is 
dried  and  exhausted  with  alcohol.  The  tincture  is  then  treated 
with  milk  of  lime  and  filtered,  and  the  dissolved  lime  separated 
by  sulphuric  acid.  This  treatment  by  lime  is  probably  intended 
to  remove  fixed  oil,  and  any  other  resinous  matter  than  the  active 
one,  should  any  be  present.  The  tincture  is  then  decolorized  by 
passing  it  through  animal  charcoal,  evaporated  to  a  syrupy  con- 
sistence, and  precipitated  by  water  and  dried.  This  process 
produces  the  pure  hemp  resin,  but  is  far  too  tedious  to  pursue 
with  the  extract,  which,  if  wholly  soluble  in  alcohol  of  90  per 
cent.,  is  sufficiently  freed  from  the  inert  matter  of  the  gunjah. 
To  obtain  the  answer  to  the  query,  it  became  necessary  to  secure 
an  authentic  specimen  of  hemp  extract,  which  was  obtained  di- 
rectly from  gunjah  of  good  quality. 
One  thousand  grains  of  gunjah  were  reduced  to  powder,  with 
the  exception  of  the  stalks,  moistened  with  half  an  ounce  of  alco- 
hol pressed  in  a  funnel,  the  stalks  thrown  on  the  top,  and  the 
whole  slowly  percolated  with  alcohol  of  '817  sp.  gr.  until  eight 
fluidounces  of  the  tincture  had  passed ;  the  process  was  then  stopped, 
and  the  tincture  reduced  to  an  extract  by  careful  evaporation. 
The  product  was  soft,  of  a  dark,  dull  green  color,  had  the  pe- 
culiar odor  of  hemp  resin  well  marked,  and  weighed  110  grains, 
equal  to  9  per  cent. 
It  had  the  following  properties  : — 
Soluble  without  appreciable  residue,  in  strong  alcohol,  ether 
and  chloroform.  Benzole  dissolved  all  but  a  small  residue  of 
blackish  green  matter,  which  is  wholly  soluble  in  alcohol ;  and 
on  the  evaporation  of  the  benzolic  solution,  the  resin  retained  its 
odor  and  other  sensible  properties. 
Oil  of  turpentine  dissolved  it  quite  readily,  and  the  solution, 
on  standing,  became  coated  with  minute  scaly  crystals,  the  na- 
ture of  which  was  not  determined. 
Olive  oil  dissolved  it  completely,  forming  a  greenish  solution, 
which  has  been  suggested  for  pharmaceutical  use  by  Laneau  and 
by  Githens. 
