110  Researches  on  the  Cinchona  Alkaloids.     |  ^™Mrr.' 'i^si ™ 
ohloric  acid ;  its  aqueous  solution  becomes  milky  on  the  addition  of 
iodide  or  sulphocyanide  of  potassium  solution,  and  produces  finally 
resinous  precipitates.  Tlie  chloroplatinate  is  a  beautiful  yellow, 
amorphous,  flocculent  precipitate. 
Apocinchonidiay  C19H22N2O,  into  which  alkaloid  also  ^  cinchonidia, 
produced  from  cinchonidia,  is  transformed  by  longer  heating,  being 
very  sparingly  soluble  in  moderately  dilute  alcohol ;  its  preparation  in 
a  pure  state  presents  no  difficulty,  and  even  by  recrystallizing  the  crude 
product  once  from  boiling  alcohol,  the  pure  base  may  be  obtained.  It 
crystallizes  in  small,  shining  laminae,  difficultly  soluble  in  ether  and 
chloroform,  and  almost  insoluble  in  cold  water;  the  alcoholic  solution 
has  an  alkaline  reaction.  It  melts  at  225°C.  (uncorr.),  acquiring  a 
dark  color ;  it  deviates  the  plane  of  polarized  light  to  the  left,  dis- 
solved in  alcohol,  —129*2°  ;  and  in  water  with  3  HCl  —160-4°.  It 
dissolves  readily  in  dilute  acids  and  is  precipitated  from  these  solutions 
by  ammonia  or  soda  in  white  amorphous  flakes,  which,  after  a  short 
time,  become  crystalline.  Its  solutions  have  a  strongly  bitter  taste,  and 
are  not  fluorescent.  The  neutral  hydrochloric  acid  solution  is  not  pre- 
cipitated by  Rochelle  salt  until  completely  saturated  with  this  salt, 
when  a  small  amount  of  a  resinous  precipitate  is  produced,  which, 
however,  upon  the  addition  of  water  again  disappears. 
The  neutral  hydrochlorate.  like  the  neutral  sidj)hate,  is  amorphous  and 
readily  soluble  in  water  and  alcohol.  The  chloroplatinate  forms  at 
first  a  flocculent  precipitate,  afterwards  becoming  crystalline,  and  is 
very  difficultly  soluble  in  water. 
Apocinchonia,  0^91122^20. — For  the  separation  of  the  apocinchonia 
from  diapocinchonia  the  contents  of  the  tube  are  nearly  neutralized  by 
ammonia,  then  an  equal  volume  of  alcohol  is  added,  the  mixture  heated 
to  boiling,  and  mixed  Avith  an  excess  of  ammonia;  the  apocinchonia 
is  thus  precipitated,  and  after  the  solution  has  become  cold  may  be 
collected,  washed  with  diluted  alcohol,  dried  between  filtering  paper, 
and  finally  recrystallized  from  boiling  alcohol.  It  is  in  colorless  prisms, 
melting  at  209°C.  (uncorr.),  insoluble  in  water,  difficultly  soluble  in 
ether  and  chloroform,  but  quite  readily  soluble  in  alcohol,  particularly 
on  boiling  ;  the  alcoholic  solution  has  an  alkaline  reaction  and  bitter 
taste.  It  deviates  the  plane  of  polarized  light  to  the  right,  dissolved 
in  alcohol  +160-0°  ;  in  water  with  2  HCl  +212-5°,  and  with  3  HCl 
+  212-3°.  Apocinchonia  crystallizes  anhydrous,  dissolves  readily  in 
acids,  and  is  precipitated  from  these  solutions  by  ammonia  or  other 
