152  Caramelization  in  Rivas's  Test.       {^Aprif  i9ioarm' 
of  a  new.  prepared  milk,  "  Monia  Milk,"  at  a  meeting  of  the  Phila- 
delphia Section  of  the  American  Chemical  Society,  caramelization 
was  again  resorted  to  as  an  explanation.4 
Caramel  is  a  dark  brown  substance  formed  when  sugar  is 
strongly  heated.  The  action  of  heat  on  cane-sugar  may  be  sum- 
marized as  follows:  When  heated,  cane-sugar  melts  at  1600  C, 
approximately.  Above  its  melting  point,  the  sugar  becomes  colored, 
and  finally  changes  into  a  brown  mass  called  caramel.3  The  action 
of  heat  produces  serious  disturbances  in  the  sugar  molecule.  This 
has  been  established  since  Lipmann  observed,  in  the  manufacture 
of  candy,  the  formation  of  small  quantities  of  dimethyl  furfurol, 
pyrocatechinol,  trioxybutyric  acid,  and  trioxyglutaric  acid.6  Stone 
later  proved  that  acetone  is  formed  simultaneously  with  caramel.7 
On  glucose,  the  action  of  heat  is  as  follows :  The  ordinary 
monohydrated  glucose,  C6H12Oe  +  H20,  loses  its  water  gradually 
and  without  fusion  at  temperatures  between  50 0  and  60 0  C.  This 
dehydration  is  completed  at  8o°  C.  with  partial  fusion.  Anhydrous 
glucose  melts  at  144 0  to  1460  C.  At  1700  C.  glucose  is  transformed 
into  glucosan,  C6H10O5,  with  the  loss  of  one  molecule  of  water.  At 
about  200 0  C.  it  darkens  and  forms  a  caramel  similar  to  that  obtained 
from  cane-sugar.8 
Caramel  then  is  distinctly  a  product  formed  from  sugars  at 
elevated  temperatures.  If  it  is  caramel  that  is  formed  at  tempera- 
tures below  the  boiling  point  of  water,  for  example  when  syrup  of 
ferrous  iodide  ages  at  ordinary  temperatures  or  when  glucose  or 
milk-sugar  is  warmed  with  alkalies  as  in  Rivas's  test  for  B.  Coli. 
it  would  present  a  case  of  exceptional  interest.  I  should  regard  it 
as  hazardous  to  assert,  without  experimental  proof,  that  because 
caramel  is  a  brown  decomposition-product  of  sugar,  therefore  every 
brown  decomposition-product  of  sugar  is  caramel,  and  every  process 
producing  brown  colors  from  sugar  is  a  process  of  caramelization. 
By  such  argument,  errors  enter  the  literature  of  science  masquerad- 
ing as  facts,  and  in  direct  opposition  to  the  aim  of  science  to  eradi- 
cate the  errors  from  the  data  accumulated. 
The  first  experiments  to  test  his  assumption  of  caramelization, 
4  Meeting,  Nov.  18,  19x19. 
5  Les  Sucres  et  Principatix  derives,  L.  Maquenne,  Paris,  1900,  p.  656. 
6  Ber.  Chan.  Gesell,,  Berlin,  26,  p.  3057. 
1  Chetn.  News,  70,  p.  117. 
s  L.  Maquenne,  he.  cit.,  p.  486. 
