Amjune,r,^7h8arm"}  The  Cinchona  Alkaloids.  301 
dextrogyre,  and  show  no  fluorescence.    The  sulphate  2C20H24N2O, 
S04H2-f-2H20  crystallizes  from  water  in  compact  prisms. 
Cinchonicia,  C20H24N2O,  anhydrous  monobasic  sulphate  of  cincho- 
nidia  or  cinchonia,  heated  to  I30°C,  or  until  they  melt,  are  transformed 
into  sulphate  of  cinchonicia.  The  alkaloid  rotates  the  plane  of  polar- 
ized light  to  the  right,  is  amorphous  and  never  present  in  cinchona 
barks.     Some  salts  are  crystallizable. 
Dicinchonia,  C40H48N4O2,  may  be  expected  in  the  chinoidin  of  such 
barks  which  contain  a  large  percentage  of  cinchonidia  or  cinchonia. 
As  yet  it  has  not  been  obtained  entirely  free  from  diconchinia. 
Homocinchonidia,  C19H22N20  (Koch's  cinchonidia,  1877),  crystal- 
lizes from  strong  alcohol  in  large  prisms  and  from  diluted  alcohol  in 
scales,  and  deviates  the  plane  of  polarized  light  to  the  left.  The 
sulphate,  —  2C19H22N20,S04H2-|-6H20,  crystallizes  in  very  delicate 
needles,  which  have  a  gelatinous  aspect,  and  while  still  moist  melt  at 
about  30°C.j  when  carefully  dried  it  resembles  magnesia  in  appearance, 
is  usually  anhydrous,  and  in  this  condition  swells  with  chloroform  to  a 
jelly-like  mass.  The  cinchovatina  (aricind)  of  Winckler,  from  Cinch, 
ovata,  is  mainly  this  alkaloid. 
Homocinchonia,  C19H22N20,  is  probably  identical  with  Skraup's 
(1877)  cinchonia^  and  appears  to  be  present  in  the  bark  of  Cinch.  rosu~ 
lenta. 
Homocinchonicia,  C19H22N20,  an  amorphous  alkaloid,  is  formed 
when  the  anhydrous  monobasic  sulphate  of  homocinchonidia  is  melted* 
Its  oxalate,  =  2C19H22N20,C2H204+4H20,  greatly  resembles  the 
corresponding  salt  of  cinchonicia. 
Dihomocinchonia,  C38H44N402,  is  amorphous,  rotates  the  plane  of 
polarization  strongly  to  the  right,  yields  amorphous  salts  and  is  also 
present  in  the  bark  of  Cinch,  rosulenta. 
ghiinamina  (chinamin),  C19H24N202,  discovered  by  the  author  (1872) 
in  the  bark  of  C.  succirubra  grown  at  Darjeeling,  and  subsequently  in 
all  barks  of  the  same  species  from  British  India  and  Java,  in  Mutis' 
Quinquina  rouge,  and  in  the  barks  of  C.  nitida,  C.  erythrantha,  C. 
erythroderma,  C.  rosulenta,  C.  calisaya  var.  Schuhkrafft  and  C.  cali- 
saya,  known  in  English  commerce  as  Para-bark.  It  is  separated  from 
the  amorphous  alkaloids  by  precipitating  the  dilute  acetic  acid  solution 
with  potassium  sulphocyanide  until  the  liquid  is  pale  yellow  ;  when 
clear  it  is  supersaturated  with  ammonia,  agitated  with  ether,  the  etherial 
