454  Examination  of  Opium  Alkaloids.      {Aoctob<£  wiT"' 
The  melting-point  of  narceine  is  variable,  depending  upon  its 
content  of  water  of  hydration.  Fully-hydrated  narceine  melts  at 
170 ° ;  the  anhydrous  base  melts  at  1630  to  1650;  admixture  with 
narceine  hydrochloride  lowers  the  melting-point. 
A  solution  of  narceine  in  hot  water  is  neutral  and  is  optically 
inactive. 
If  about  0.01  Gm.  of  narceine  be  dissolved  in  10  Cc.  of  water 
containing  a  few  drops  of  hydrochloric  acid,  a  few  drops  of  a  very 
weak  iodine  solution  (about  1  in  1000)  added,  and  the  mixture 
shaken  for  several  minutes,  a  dark  blue  precipitate  should  be  pro- 
duced (distinction  from  other  opium  alkaloids). 
If  about  0.01  Gm.  of  narceine  be  dissolved  in  10  Cc.  of  warm 
water  containing  a  few  drops  of  hydrochloric  acid,  the  solution 
cooled,  and  a  few  drops  of  potassium-zinc  iodide  solution  added,  a 
precipitate  of  white,  hair-like  crystals  should  slowly  be  formed; 
the  crystals  become  blue  on  standing  (distinction  from  other  opium 
alkaloids) . 
If  about  0.01  Gm.  of  narceine  be  dissolved  in  5  Cc.  of  water 
containing  a  few  drops  of  hydrochloride  acid  and  1  Cc.  of  chlorine 
water  added,  followed  by  an  excess  of  ammonia  water,  an  orange- 
red  coloration  should  be  produced  (distinction  from  thebaine,  which 
gives  a  reddish-brown  color) . 
If  about  0.001  Gm.  of  narceine  be  dissolved  in  0.1  Cc.  of  nitric 
acid  a  rapidly  fading  yellow  color  should  be  produced. 
If  about  0.001  Gm.  of  narceine  be  dissolved  in  0.1  Cc.  of  sul- 
phuric acid  a  yellowish-brown  coloration  should  be  produced ;  this 
slowly  changes  to  cherry  red  on  standing ;  more  quickly  on  warming. 
If  about  0.001  Gm.  of  narceine  be  dissolved  in  0.2  Cc.  of  sul- 
phuric acid  in  which  about  0.001  Gm.  of  gallic  acid  has  previously 
been  dissolved,  a  brownish-yellow  solution  should  be  produced;  on 
cautiously  heating  the  solution  it  successively  becomes  green,  bluish- 
violet,  and  finally  dark  violet. 
If  about  0.01  Gm.  of  narceine  be  evaporated  with  diluted  sul- 
phuric acid  on  a  water-bath,  a  violet  coloration  should  be  produced; 
this  changes  to  cherry  red  on  further  heating;  when  cold,  this  yields, 
on  the  addition  of  a  trace  of  nitric  acid  or  potassium  nitrate,  streaks 
of  a  blue-violet  color. 
If  about  0.001  Gm.  of  narceine  be  dissolved  in  0.1  Cc.  of  sulphuric 
acid  which  contains  a  trace  of  iodic  acid,  a  chocolate-brown  color 
should  be  produced. 
If  about  0.01  Gm.  of  narcotine  be  dissoved  in  1  Cc.  of  water 
