ACTION  OF  LIGHT  ON  CITRATE  OF  IRON  AND  QUININE.  829 
Benzine,  ether  and  chloroform  dissolve  anhydrous  sulphurous 
acid  ;  the  two  first  afford -yellow  solutions. — Jour,  de  Pharmacie^ 
Mai,  1869. 
THE  ACTION  OF  LIGHT  ON  CITRATE  OF  IRON  AND 
QUININE. 
By  C.  H.  Wood,  F.  C.  S. 
I  was  engaged  about  two  years  ago  in  preparing  some  citrate 
of  iron  and  quinine,  and  by  scaling  my  product  in  a  hot  cupboard 
I  obtained  good  sized  scales — bright,  of  a  golden  green  color, 
and  perfectly  soluble  in  water.  Remembering,  however,  that 
potassio-tartrate  of  iron  gives  far  better  scales  when  scaled  in 
the  sun's  rays,  than  by  any  artificial  heat  (a  fact  I  learnt  from 
Mr.  Braithwaite),  I  spread  some  of  my  solution  on  plates  of 
glass,  and  exposed  them  in  a  window  to  an  April  sun.  I  was 
soon  surprised,  however,  to  observe  the  citrate  becoming  darker 
in  color  and  exhibiting  a  very  good  photographic  image  of  some 
bottles  which  cast  their  shadows  on  the  plates.  After  a  time, 
but  while  still  wet,  it  gradually  became  opaque,  as  if  the  quinine 
had  been  precipitated.  It  ultimately  came  off  in  minute  brown- 
ish colored  powdery  scales.  The  two  results  from  the  same  so- 
lution were  as  different  as  they  possibly  could  be.  The  sun- 
scaled  specimen  when  put  into  water  became  white  and  opaque, 
and  only  dissolved  after  the  lapse  of  a  long  time.  The  scales 
produced  by  heat,  when  thrown  on  water,  rapidly  melted,  retain- 
ing their  perfect  transparency  to  the  last.  The  salt  contained 
17  per  cent,  of  quinia. 
I  then  thought  it  would  be  worth  while  to  ascertain  whether 
the  strong  solution  only  is  subject  to  this  change,  or  whether  the 
finished  product  would  be  also  affected  in  like  manner  by  exposure 
to  light.  About  a  drachm  of  the  good  citrate,  scaled  by  heat  and 
dissolving  freely  without  opacity,  was  therefore  spread  out  on  a 
sheet  of  white  paper  and  laid  in  the  sun's  rays.  After  a  quarter 
of  an  hour's  exposure,  it  was  perceptibly  deepened  in  color.  In 
twenty  minutes  it  had  become  brownish,  and  when  put  into  water 
became  at  once  white  and  opaque.  The  white  spongy  bits  floated 
about  in  the  liquid,  and  gradually  but  slowly  dissolved.  Some 
samples  of  citrate  of  iron  and  quinine  were  then  obtained  from 
