Am.  Jour.  Pharm. ) 
Jan.,  1880.  J 
Goto  Barks, 
23 
common  temperature  upon  cotoin  dissolved  in  chloroform,  evaporating 
the  solvent  and  crystallizing  from  hot  alcohol.  It  crystallizes  in  yel- 
low prisms,  melts  at  II4°C.,  is  nearly  insoluble  in  cold  water,  but  dis- 
solves gradually  in  boiling  water  with  a  dark  blood-red  color.  It  is 
readily  soluble  in  alcohol,  chloroform  and  ether,  and  is  colored  yellow 
by  cold,  and  dissolved  by  warm  sulphuric  acid  with  a  dingy-brown 
color.     Warm  nitric  acid  produces  a  reddish-yellow  resin. 
Triacetylcotoin^  Q.^^^^O^  {Q^^O.^^^  is  obtained  in  large  prisms  on 
heating  cotoin  with  acetic  anhydrid  in  a  sealed  tube  to  160°  or  lyo^C. 
for  two  hours,  and  recrystallizing  from  boiling  water.  It  is  freely  soluble 
in  chloroform  and  ether,  less  in  cold  alcohol,  and  is  not  colored  by  ferric 
chloride  or  warm  nitric  acid. 
DicoTOiN. — On  treating  crude  cotoin  with  boiling  water,  repeating 
the  operation  with  the  mother-liquor  from  the  crystallized  cotoin,  after 
a  whiTe  the  foliaceous  crystals  increase  in  quantity  and  require  to  be 
separated  mechanically  from  the  cotoin.  The  authors  formerly  called 
this  compound  cotonetin^  and  gave  it  the  formula  ^^^if^^^ ;  but  it  is 
now  regarded  as  dicotoin^  of  the  formula  C^^^Hg^O^j.  It  melts  in  boil- 
ing water  and  dissolves  sparingly,  separating  on  cooling  again  in  pale 
yellow  plates  like  cotoin.  On  dissolving  the  residue  in  ether,  treating 
with  animal  charcoal  and  evaporating  spontaneously,  a  yellow  amor- 
phous mass  is  obtained,  which  soon  changes  to  tabular  crystals  of 
cotoin.  Dicotoin  is,  therefore,  the  anhydrid  of  cotoin  \  it  crystallizes 
in  nearly  white  scales,  which  are  readily  soluble  in  alcohol,  aceton, 
ether,  chloroform,  ammonia  and  soda  solution.  Its  alcoholic  solution 
IS  colored  strongly  brown-red  with  ferric  chloride,  and  its  solution  in 
ammonia  yields  with  lead  acetate  an  amorphous  yellow  precipitate  of 
variable  composition. 
Paracotoin. — The  concentrated  etherial  tincture  of  paracoto  bark 
congeals  in  a  few  days  to  a  crystalline  mass,  consisting  of  paracotoin, 
leucotin,  oxyleucotin  and  dibenzoyl-hydrocoton.  This  is  expressed  to 
separate  the  resinous  mother-liquor  and  recrystallized  in  fractions  from 
hot  alcohol,  from  which  paracotoin  crystallizes  first.  It  is  pure,  when 
on  boiling  with  strong  nitric  acid  it  is  colored  yellow  or  brownish-yel- 
low, but  not  blue  green.  It  forms  pale  yellow,  shining  laminae,  melting 
at  I52°C.,  congealing  at  I48°C.,  and  subliming  at  a  higher  tempera- 
ture. It  is  easily  soluble  in  ether,  chloroform,  and  in  boiling  alcohol, 
aceton  and  benzol  \    also  somewhat  soluble  in  boiling  water  and 
