DEPORTMENT  OF  ALKALOIDS  WITH  REAGENTS,  ETC.  449 
precipitate  as  potassa  and  ammonia,  but  fail  to  redissolve  it  upon 
addition  in  excess.  Consequently  if  a  fixed  alkaline  carbonate 
is  added  to  a  solution  of  morphia  in  caustic  potassa,  Mo  -f  2  Aq. 
separates,  especially  after  previous  ebullition,  in  the  form  of  a 
crystalline  powder.  A  more  minute  inspection,  particularly 
through  a  magnifying  lens,  shows  this  powder  to  consist  of  small 
acicular  crystals.  Seen  through  a  magnifying  glass,  which 
magnifies  100  times,  these  crystals  present  the  form  of  four-sided 
prisms.  Bicarbonate  of  soda  and  bicarbonate  of  potassa  speedily 
produce,  in  solutions  of  neutral  salts  of  morphia,  a  precipitate 
of  hydrated  morphia  in  the  form  of  a  crystalline  powder.  The 
precipitate  is  insoluble  in  an  excess  of  the  precipitant.  These 
reagents  fail  to  precipitate  acidified  solutions  of  morphia  salts 
in  the  cold. 
The  action  of  strong  nitric  acid  upon  morphia,  or  one  of  its 
salts,  in  the  solid  state  or  in  concentrated  solutions,  produces  a 
fluid  varying  from  red  to  yellowish  red.  Dilute  solutions  do  not 
change  their  color  upon  addition  of  nitric  acid  in  the  cold,  but 
upon  boiling  they  acquire  a  yellow  tint.  Neutral  sesquichloride 
of  iron  imparts  to  neutral  solutions  of  morphia  salts  a  beautiful 
dark  blue  color,  which  disappears  upon  the  addition  of  an  acid. 
If  the  solution  contain  an  admixture  of  animal  or  vegetable  ex- 
tractive matter,  or  of  acetates,  the  color  will  appear  clouded  and 
less  distinct.  If  iodic  acid  is  added  to  a  solution  of  morphia 
or  a  salt  of  morphia,  iodine  separates.  In  concentrated  aqueous 
solutions  the  separated  iodine  appears  as  a  kermes-brown  pre- 
cipitate, whilst  to  alcoholic  or  diluted  aqueous  solutions  it  imparts 
a  brown  or  yellowish  brown  color.  The  addition  of  starch  paste 
to  the  fluid  considerably  heightens  the  delicacy  of  the  reaction, 
since  the  blue  tint  of  the  iodide  of  starch  remains  still  perceptible 
in  exceedingly  dilute  solutions,  which  is  not  the  case  with  the 
brown  color  imparted  by  iodine.  As  other  nitrogenous  bodies 
(albumen,  casein,  fibrin,  etc.,  etc.)  likewise  reduce  iodic  acid,  this 
reaction  has  only  a  relative  value. 
Second  Group. — Alkaloids  which  are  precipitated  by  potassa 
from  the  solutions  of  their  salts,  but  do  not  redissolve  to  a  per- 
ceptible extent  in  an  excess  of  the  precipitant,  and  are  precipi- 
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