ON  SOME  SACCHARINE  SUBSTANCES. 
157 
which  one  is  capable,  and  the  other  incapable  of  fermentation  ; 
the  latter  must  be  placed  near  sorbine. 
Melitose,  as  extracted  by  water  from  Australian  manna,  crys- 
tallizes in  extremely  fine  needles ;  it  is  about  as  soluble  as 
mannite,  and  has  a  slight  sweet  taste.  It  rotates  the  plane  of 
polarization  to  the  right ;  its  rotatory  power  (with  reference  to 
the  transition-color)  is  — -f88°.  It  is  therefore  about  one- 
fourth  greater  than  that  of  cane-sugar.  When  crystallized  at 
the  ordinary  temperature,  melitose  has  the  formula  C12H12012-f- 
2HO.  At  212p  F.  it  becomes  semifluid,  and  loses  1  atom  of 
water.  At  266°  F.  it  loses  a  fresh  quantity  of  water  ;  at  a  higher 
temperature  it  undergoes  a  change  and  becomes  yellow,  and  at 
still  higher  one  it  diffuses  the  odor  of  caramel.  When  kept  at 
392°  F.  with  muriatic  acid  for  a  long  time,  it  is  converted  into  a 
blackish-brown  mass.  When  heated  with  baryta  for  some  hours 
to  212°  F.,  it  does  not  acquire  color,  and  retains  its  characteris- 
tic properties.  Melitose  does  not  reduce  the  copper  from  the 
solution  of  potash  and  oxide  of  copper ;  it  only  acquires  this 
property  by  boiling  with  sulphuric  acid.  By  this  means  it  also 
loses  about  a  third  of  its  rotatory  polarizing  power,  and  when 
isolated  it  is  uncrystallizable. 
In  contact  with  yeast  it  furnishes  alcohol  and  carbonic  acid. 
Melitose,  boiled  with  sulphuric  acid  and  with  baryta  at  212°  F., 
also  possesses  this  property.  All  these  properties  agree  very 
closely  with  those  of  cane-sugar.  But  during  fermentation  100 
parts  of  melitose,  C12H12012+2HO,  only  furnish  22-2  parts  of 
carbonic  acid  ;  100  parts  of  grape-sugar,  C12H12012-f  2HO,  give 
44«5  parts  of  carbonic  acid,  or  double  the  quantity.  The  fer- 
mented fluid  contains  a  saccharine  body,  which  is  not  acted  upon 
in  fermentation.    This  the  author  calls, — 
Eucalyne. — Its  composition,  dried  at  212°  F.,  is  C12H12012. 
Treatment  with  sulphuric  acid  does  not  render  this  body  capable 
of  fermentation*  Melitose  furnishes  exactly  half  its  weight  of 
eucalyne,  as  proved  by  direct  experiment.  Perhaps  also  treat- 
ment with  sulphuric  acid  only  converts  half  the  melitose  into  the 
sugar  which  reduces  the  copper  in  the  test-fluid. 
2.  Finite. — The  author  has  received  a  sugar  from  M.  Bourgier 
de  la  Riviere,  from  California.  It  is  said  to  be  derived  from 
Pinus  Lambertiana.    It  collects  in  concrete  masses  in  hollows 
