MELEZITOSE,  A  NEW  SPECIES  OF  SUGAR. 
61 
during  the  rather  tedious  evaporation,  a  few  drops  of  nitric  acid 
stirred  into  the  fusing  salt  clears  it  at  once,  by  converting  all 
the  carbonaceous  matters  into  carbonic  acid,  which  latter,  of 
course,  flies  off  with  the  excess  of  nitric  acid. 
The  writer  has  never  used  the  officinal  process  for  this  prepara- 
tion, having  at  first  given  a  preference,  upon  theoretical  grounds, 
to  that  wherein  the  iron  is  precipitated  by  freshly  prepared 
oxide  of  zinc  and  chlorine,  and  from  having  been  well  satisfied 
with  the  results  obtained. 
ON  MELEZITOSE,  A  NEW  SPECIES  OF  SUGAR. 
By  M.  Berthelot. 
In  pursuing  the  study  of  the  saccharine  matters,  I  found, 
some  years  ago,  in  the  manna  of  Brian gon — a  saccharine  exu- 
dation produced  by  the  larch  (meleze)  and  formerly  employed 
in  pharmacy—a  new  sugar  analogous  to  cane  sugar,  but  of 
which  I  was  unable  to  follow  up  the  study,  from  want  of  matter. 
Having  since  then  succeeded  in  procuring  a  sufficient  sample  of 
this  manna,  thanks  to  the  kindness  of  M.  Meissas,  formerly 
Professor  of  Mathematics  at  the  Lyce*e  Napoleon,  I  resumed 
the  study  of  it,  and  I  succeeded  in  isolating  and  characterising 
the  sugar  which  it  contains  ;  it  is  a  new  substance,  very  inter- 
esting from  its  analogy  to  cane  sugar ;  I  shall  designate  it  by 
the  name  of  melezitose. 
To  extract  it,  the  manna  of  Briancon  is  treated  with  boiling 
alcohol,  evaporated  to  the  consistence  of  an  extract,  and  left  to 
itself  for  some  weeks.  Melezitose  crystallises  in  a  syrupy 
mother-liquor;  it  .is  compressed,  washed  with  warm  alcohol, 
and  re-crystallised  in  boiling  alcohol;  very  small,  hard  and  bril- 
liant crystals  are  thus  obtained :  examined  in  the  microscope, 
they  appeared  to  be  oblique  rhomboidal  prisms,  analogous  to 
those  of  cane  sugar.  I  could  not  obtain  them  of  sufficient  size 
to  measure  their  angles.  These  crystals,  viewed  in  the  mass, 
present  an  opaque  appearance,  which  isolated  crystals  do  not. 
Their  taste  is  sweet,  analogous  to  that  of  glucose,  and  conse- 
quently much  weaker  than  that  of  cane  sugar.  They  are  very 
soluble  in  water,  almost  insoluble  in  cold  alcohol,  sparingly  sol- 
