35° 
Quiniretin. 
(  Am.  Jour.  Pharm. 
1       July,  1878. 
ning  at  the  surface.  By  and  by  it  becomes  turbid,  and  after  a  few  days 
a  flocculent  brown  matter  sinks  down,  amounting  when  dry  to  nearly 
the  quantity  of  quinia  originally  employed.  A  very  little  of  it  remains 
in  solution,  for  the  latter  remains  brownish  and  has  always  a  bitter  taste, 
reminding  of  quinia.  Yet  in  the  clear  solution  the  alkaloid  is  present 
in  so  trifling  an  amount  that  the  brown  liquid  becomes  but  very  faintly 
turbid  on  addition  of  either  tannic  acid  or  iodohydrargyrate  of  iodide  of 
potassium.  By  both  these  tests,  as  well  known,  precipitates  are  pro- 
duced in  a  solution  containing  even  less  than  1  part  of  quinia  in  2,300 
parts  of  water  before  it  is  submitted  to  the  action  of  light. 
The  transformation  of  quinia  into  the  brown  flocculent  substance, 
which  for  the  sake  of  brevity  may  be  termed  quiniretin,  is  due  to  sun- 
light exclusively.  If  water  is  boiled  in  order  to  deprive  it  of  air  as  much 
as  possible,  and  then  saturated  with  quinia,  the  cooled  filtered  solution 
keeps  perfectly  colorless  until  it  is  exposed  to  sunlight,  when  it  soon 
begins  to  turn  yellowish.  It  is  true,  however,  that  in  a  closed  tube,  in 
the  dark,  the  aqueous  solution,  if  quinia,  turns  red,  yet  not  brown,  as 
soon  as  it  is  heated  to  I70°C.  ;  at  3000  it  affords  an  intensely  red 
liquid.  The  effect  of  sunlight  is  the  same  if  the  solution  of  quinia  is 
deprived  of  air  by  a  current  of  hydrogen  and  the  tube  immediately 
closed  ;  the  solution  thus  absolutely  deprived  of  oxygen  becomes  brown 
in  sunlight. 
The  brown  substance,  which  I  call  quiniretin,  must  therefore  con- 
tinue to  have  the  same  composition  as  quinia,  but  it  is  modified  in  an 
extremely  remarkable  way  ;  it  is  neither  quinia  or  quinicia,  nor  does  it 
contain  a  trace  of  either.  Quiniretin  is  devoid  of  an  alkaline  reaction, 
insoluble  in  both  alcohol  and  ether  as  well  as  in  hot  or  cold  water, 
softening  but  a  little  in  boiling  water.  It  is  not  fusible,  but  melts  only 
far  above  the  melting  point  of  quinia,  yet  quiniretin  then  undergoes  a 
thorough  decomposition. 
Quiniretin  is  dissolved  by  acids,  but  unable  to  neutralize  them  or  to 
combine  with  them.  It  is  abundantly  soluble  in  hydrochloric  acid 
I'll  sp.  gr.  ;  this  solution  displays  an  intensely  brown  color,  and  may 
be  diluted  with  water  without  becoming  turbid.  Its  very  bitter  taste 
reminds  of  that  of  quinia,  but  it  is  at  the  same  time  somewhat,  I  may 
say,  aromatic.  The  hydrochloric  solution  of  quiniretin  is  not  precipi- 
tated by  tannic  acid  ;  this  is  likewise  in  favor  of  the  statement  that  it 
is  not  an  alkaloid.    The  solution  is  precipitated,  on  the  other  hand,  as 
