"^"sepr'issr'"' }  ^'^^eparation  and  Composition  of  Colchicin.  445 
Of  the  reactions  of  colchicin  many  are  not  afforded  by  colchicoresin 
without  possessing  other  characteristic  reactions.  The  color  reaction 
with  potassium  nitrate  and  sulphuric  acid,  or  with  solution  of  potassa^ 
is  produced  the  same  as  with  colchicin  ;  with  tannic  acid  or  with  iodi- 
nized  potassium  iodide  a  turbidity  is  only  produced  after  some  time,, 
while  with  phosphomolybdic  acid  a  precipitate  is  immediately  pro- 
duced. Ferric  chloride  produces  in  very  dilute  solutions  a  brownish- 
green  coloration.  At  100°C.  it  becomes  soft,  like  wax,  and  melts  at 
a  higher  temperature  without  decomposition. 
By  treatment  with  mineral  acids.two  other  substances  were  obtained^ 
which,  together  with  colchicein,  appear  by  the  decomposition  of  col- 
chicin with  mineral  acids,  viz.,  a  resinous  substance,  insoluble  in  water 
(beta-colchicoresin),  and  a  substance  readily  soluble  in  water ;  but  no 
colchicein  could  be  obtained  therefrom.  Colchicoresin  is  without 
action  upon  litmus,  and  indifferent  in  its  behavior  towards  polarized 
light.  When  dried  at  100°C.  until  of  constant  weight  it  afforded 
0'73  per  cent,  of  ash,  and  gave  upon  analysis  numbers  which  corres- 
pond to  the  empirical  formula  C5iHgQN20^5. 
Colchicoresin  is  not  contained  in  the  unripe  seed  or  tubers,  but  is 
present  to  a  considerable  extent  in  the  dead  leaves  surrounding  the 
tuber,  and  also  in  the  dried  seed  and  tubers  to  an  amount  equal  to 
that  of  the  colchicin,  so  that  it  may  be  accepted  that  the  color  of  the 
ripe  seed  is  due  to  the  colchicoresin. 
Chemical  Properties  of  Colchicin. — As  prepared  by  the  autlior  it  i& 
amorphous,  and,  when  obtained  from  the  dried  seed,  and  in  its  purest 
possible  form,  of  a  sulphur-yellow  color,  while  from  fresh  summer 
tubers  it  is  obtained  colorless  and  transparent.  It  could  not  be 
obtained  by  any  method  in  a  crystalline  form.  It  possesses  a  very 
slight  alkaline  reaction,  which  only  appears  upon  litmus  paper  when 
the  latter  has  become  nearly  dry,  so  tliat  this  may  possibly  be  depend- 
ent upon  the  formation  of  ammonia,  while  the  basic  properties,  as 
described  by  Geiger  and  Hesse,  Schoonbrood  and  Maisch,  could  not  be 
observed.  Colchicin  is  much  rather  a  very  indifferent  body,  which  is 
capable  of  combining  with  proportionately  very  few  bodies,  and,  as  it 
would  appear,  combines  with  no  acid  to  form  a  chemical  compound. 
It  does  not  combine  with  ethyl  iodide,  and  the  only  known  compound 
worthy  of  consideration  is  that  with  tannic  acid,  which  also,  accord- 
ing to  Hiibler's  analyses,  does  not  possess  a  constant  composition.  It 
deserves,  therefore,  as  Hiibler  has  previously  observed,  on  account  of 
