446  Preparation  and  Composition  of  Colchicin.  {^^sei,r'^si^"^' 
its  indiiference,  and  as  possessing  but  little  in  common  with  the 
organic  bases,  to  be  removed  from  the  latter  group.  It  melts  at 
145°C.,  assuming  a  brown  color,  and,  upon  cooling,  becomes  glass- 
like and  brittle ;  it  is  without  action  upon  polarized  light. 
A  portion  of  colchicin  which  had  been  repeatedly  purified,  and 
dried  at  105°C.,  afforded  upon  analysis  numbers  which  correspond  to 
the  empirical  formula  Ci^HgsNOg. 
ColcJiicein. — This  was  obtained  by  the  author  by  heating  1  part  of 
<3olchicin,  dissolved  in  about  30  parts  of  water,  with  2  parts  of  25  per 
cent,  hydrochloric  acid,  upon  the  steam-bath.  After  purification,  by 
means  of  boiling  water,  it  was  obtained  perfectly  white  and  odorless. 
It  dissolves  readily  in  alcohol,  chloroform  and  solution  of  potassa, 
with  a  yellow  color;  it  is  also  soluble  in  ammonia  water,  separating 
in  a  crystalline  form  by  the  evaporation  of  its  solution.  From  its 
solution  in  absolute  alcohol  or  chloroform  it  is  deposited  upon  evapo- 
ration as  a  yellow  varnish-like  coating,  which,  however,  when  dis- 
solved in  diluted  alcohol,  again  affords  upon  evaporation  crystals  of 
unchanged  colchicein.  It  melts  at  150°C.,  assuming  a  yellow  color, 
and  becoming  brittle  upon  cooling;  when  heated  to  200°C.  it  acquires 
a  brown  color,  and  can  no  longer  be  obtained  in  a  crystalline  form. 
Colchicein  crystallizes  in  two  different  forms  of  the  rhombic  system  : 
from  its  alcoholic  solution  in  rhombic  tables,  and  from  the  original 
hydrochloric  acid  liquid  in  rhombic  prisms ;  it  deviates  the  plane  of 
polarization  to  the  left.  When  heated  for  some  time  with  a  little 
water  at  the  temperature  of  the  water-bath,  it  is  converted  into  a  yel- 
lowish-brown mass,  which  is  uncrystallizable  and  has  great  similarity 
with  colchicin.  By  the  evaporation  of  the  mother-liquid  of  colchi- 
cein colchicin  is  likewise  obtained.  The  behavior  of  colchicein 
toward  reagents  is  in  general  the  same  as  that  of  colchicin,  but  it  is 
not  precipitated  by  tannic  acid.  When,  however,  a  saturated  aqueous 
solution  of  colchicein  is  allowed  to  stand  for  several  days,  it  then 
affords  a  precipitate  with  tannic  acid,  which  would  indicate  that  by 
prolonged  contact  with  water,  or  by  warming  therewith,  colchicein  is 
inversely  converted  into  colchicin.  Acid  solutions  of  colchicein  show 
the  same  behavior  towards  reagents  as  neutral  solutions;  its  most 
characteristic  reaction  is  with  ferric  chloride,  which,  even  in  very 
dilute  solutions,  produces  a  beautiful  green  coloration.  When  dried 
at  110°C.  it  lost,  as  an  average,  10*998  per  cent,  of  water,  and 
