Am  \JpTiir'i9ihoarm' }       Cafamelization  in  Rivass  Test.  155 
lower  aqueous  layer.  A  fairly  large  amount  of  the  original  whiskey 
was  now  treated  with  the  proper  amount  of  Marsh's  reagent,  and 
the  colorless  aqueous  layer  drawn  off  by  the  aid  of  a  separator)' 
funnel.  This  lower  layer  immediately  became  brown  when  made 
alkaline,  showing  that  the  brown  color  was  due  to  some  substance 
extracted  from  the  whiskey  in  the  test.  These  results  show  the 
inadequacy  of  Marsh's  test  for  caramel  in  alkaline  liquids,  and  they 
also  indicate  the  direction  in  which  one  may  look  for  an  explanation 
of  the  brown  color  formed  when  glucose  is  heated  with  alkalies. 
Before  going  further  in  this  direction,  however,  some  other  experi- 
ments should  be  described. 
I  tried  to  obtain  spectroscopic  evidence  of  the  similarity  or  dis- 
similarity of  the  browned  glucose  solutions  and  the  solutions  of  the 
caramel  made  by  heating  glucose  at  200°  C,  and  the  solution  of 
"  caramel  brown."  But  none  of  them  showed  absorption  bands  in 
the  visible  spectrum,  under  the  conditions  of  the  experiment. 
Oxygen  gas  (from  an  S.  S.  White  cylinder  of  compressed 
oxygen)  was  then  bubbled  through  the  same  three  solutions.  The 
color  of  the  browned  glucose  solution  began  to  fade  very  soon, 
whereas  that  of  the  other  two  solutions  was  unchanged.  The  gas 
was  passed  through  the  solution  of  the  caramel  made  by  heating 
glucose  at  2000  C.  for  15  minutes  without  effect. 
The  last  experiment  performed  was  intended  to  test  the  validity 
of  perhaps  the  strongest  argument  for  the  assumed  formation  of 
caramel  when  glucose  solutions  are  heated  with  alkalies.  These 
solutions  are  described  in  some  works  on  urinalysis  as  smelling  of 
caramel,  especially  after  they  have  been  acidified.12  Now  it  is  true 
that  an  odor  of  burnt  sugar  is  frequently  associated  with  caramel, 
but  I  failed  to  find  this  odor  described  as  one  of  the  properties  of 
purified  caramel.1"  Because  I  noticed  that  the  solutions  when  hot 
and  acid  smelled  more  strongly  than  when  cold,  I  subjected  such  a 
solution  to  distillation  in  a  current  of  steam.  The  colorless  dis- 
tillate contained  the  odoriferous  substance.  I  presume  one  must 
now  abandon  as  misleading  any  argument  based  upon  the  so-called 
smell  of  caramel.    It  is  evident  from  this  one  experiment  that  the 
12  Hammersten,  Physiological  Chem.,  Mandel's  Translation,  N.  Y.,  1900, 
p.  80.    See  "  Moore's  Test." 
13  Sabanajeff  and  Antuschewitsch,  /.  russ.  Chem.  Soc,  1893,  p.  23;  L. 
Maquenne,  loc.  cit.,  p.  660. 
