28         ON  A  TEST  FOR  THE  RESIN  OF  CANNABIS  INDICA. 
Sulphuric  acid  acts  slowly  on  the  resin  in  the  cold,  more  rapid- 
ly hot,  without  intumescence,  and  when  diluted  with  water,  a 
greyish  precipitate  falls. 
Nitric  acid,  sp.  gr.  1*38,  when  cold,  slowly  attacks  the  ex- 
tract, but  when  heated,  rapid  reaction  occurs,  red  fumes  are 
evolved,  and  the  resin  is  converted  into  an  orange  red  resinoid 
substance,  about  as  abundant  as  the  resin  treated.  This,  when 
washed  with  water  and  dried,  has  the  appearance  of  minute  frag- 
ments of  gamboge,  which  it  closely  resembles  in  color. 
This  substance  is  readily  soluble  in  alcohol,  ether  and  chloro- 
form, and  does  not  crystallize  from  these  solutions  on  evapora- 
tion ;  it  is  also  soluble  in  solutions  of  potassa  and  ammonia  and 
methylic  alcohol,  but  is  insoluble  in  benzole  and  acetic  acid,  and 
appears  to  possess  an  acid  reaction  with  litmus. 
Liquor  potassce  acts  but  slightly  on  this  extract,  apparently 
removing  little  besides  matter  soluble  in  water,  and,  perhaps, 
fatty  oil  when  present,  and  a  part  of  the  green  coloring  matter. 
Of  these  reactions  those  best  calculated  to  indicate  true  hemp 
resin  extract,  are  : — 
1st.  Its  odor  when  moderately  heated. 
2d.  Its  indifference  to  alkalies. 
3d.  Its  solubility  in  alcohol,  ether,  chloroform,  benzole  and 
turpentine ;  and 
4th.  The  reaction  of  nitric  acid,  which  is  the  best  marked  test. 
Before  trying  other  resins  it  was  deemed  best  to  procure  some 
American  grown  hemp,  and  make  an  extract  from  it  with  the  same 
menstruum.  Fortunately  that  this  was  easily  accomplished,  and 
the  tops  only  of  vigorous  specimens  of  the  cannabis  were  selected, 
dried  and  powdered.  The  color  was  deep  grass  green,  the  odor 
rank,  but  different  from  gunjah.  Three  hundred  grains  were 
reduced  to  powder,  and  treated  with  the  same  alcohol  in  like 
proportion  as  in  the  preceding  experiment,  and  a  soft  extract, 
weighing  thirty-seven  grains,  was  obtained. 
The  color  of  this  extract  was  a  brighter  green,  and  its  odor 
quite  different  from  the  extract  of  gunjah;  it  rubbed  down  readily 
with  liquor  potassoe,  making  a  dark  colored  liquid,  not  all  in 
solution.  When  treated  with  hot  nitric  acid,  rapid  effer- 
vescence   of    nitric    oxide    followed,   leaving    a  yellowish 
