AmNov.r;il8h6arm'}       Turmeric  and  its  Coloring  Matter.  557 
Hot  water  takes  up  a  little  more,  although  it  does  not  dissolve  the 
whole  of  the  coloring  principled 
Cold  alcohol  acquires  a  yellow  color,  and  dissolves  a  quantity  of 
the  resinous  matter,  but  hot  alcohol  dissolves  out  much  more,  and 
assumes  a  dark  reddish-brown  color. 
If  this  alcoholic  solution  be  evaporated,  and  the  residue  again  acted 
on  by  ether,  the  ether  will  dissolve  out  the  whole  of  the  yellow 
coloring  matter. 
If  the  solutions  are  evaporated  and  dried,  a  resinous  matter  of  a 
deep  brown  color  will  remain. 
The  simplest  method  of  extracting  curcumin  is  to  macerate  the 
powdered  root  in  boiling  water,  until  the  liquid  ceases  to  acquire  any 
further  tint.  Then  boil  the  residue  in  alcohol.  The  root  is  thus 
nearly  exhausted,  although  the  powder  always  remains  more  or  less 
colored. 
Mix  the  solutions,  which  should  be  of  a  reddish-brown  color,  and 
filter.  The  filtrate,  on  evaporation,  yields  a  brown  mass,  which 
should  be  dissolved  in  ether,  and  again  slowly  evaporated,  when  the 
curcumin  will  remain  in  thin  transparent  layers. 
When  carefully  dried,  and  reduced  to  a  fine  powder,  it  is  of  a  rich 
yellow  color,  having  the  odor  of  vanilla.  It  melts  at  a  temperature 
of  50°  C,  and  even  at  ordinary  temperature  the  powder,  if  fine,  be- 
comes soft  and  forms  into  a  mass. 
On  exposure  to  sunlight  it  gradually  loses  its  color  and  becomes 
nearly  white.  It  burns  with  a  bright  flame.  Curcumin  is  insoluble 
in  water,  but  soluble  in  ether,  chloroform  and  alcohol.  Insoluble  in 
dilute  acids,  but  soluble  in  strong.  With  strong  sulphuric  acid  it 
forms  a  solution  of  a  crimson  color,  which  disappears  if  water  is 
added,  and  the  curcumin  is  precipitated  in  yellow  flakes.  When 
treated  with  hydrochloric  and  phosphoric  acid  it  acts  in  the  same 
manner,  but  with  acetic  acid  no  change  in  color  is  produced. 
On  adding  some  boracic  acid  to  an  alcoholic  solution  and  evapo- 
rating, it  gives  a  beautiful  crimson  powder.  With  acetate  of 
lead  the  solution  gives  a  dark  red  precipitate,  and  with  nitrate 
of  lead  a  yellow  precipitate.  Nitric  acid  has  a  peculiar  action  on  cur- 
cumin. 
If  one  part  of  curcumin  is  mixed  with  2  parts  of  nitric  acid  and 
same  quantity  of  water,  on  the  application  of  heat  a  rapid  action  takes 
place  accompanied  by  a  brisk  ebullition.    If  still  kept  at  a  gentle 
