AmjJu0i^'i9ooarm'}      Study  of  Astragulus  Caryocarpus.  323 
tion.  The  substance  was  amorphous.  It  dissolved  in  alcohol  with 
difficulty,  and  precipitated  out  on  evaporating  off  the  alcohol  as  a 
fine  crystalline  powder.  'When  first  precipitated  it  was  light  brown, 
but  on  standing  for  some  time  it  changed  to  a  dark  brown.  The 
purified  substance  had  a  melting  point  of  i86°-i88°  C.  An  analy- 
sis indicated  a  hydrazone  of  a  hexose. 
No  conclusion  can  be  drawn  from  the  above  facts  as  to  the  size 
of  the  molecule.  Many  of  the  more  complex  sugars  break  down 
by  treating  with  phenylhydrazine  into  simple  hexoses  and  then  form 
hydrazones.  It  is  possible  that  such  a  reaction  takes  place  here,  as 
it  is  necessary  to  boil  for  some  little  time  before  the  hydrazone  is 
formed.  Another  indication  that  the  substance  breaks  down  is  the 
fact  that  the  optical  activity  changes  by  boiling  or  on  standing.  As 
an  instance  of  the  change  in  the  specific  rotation,  a  half  pound  of  the 
once  purified  syrupy  mass  was  placed  in  a  desiccator  over  sulphuric 
acid  and  allowed  to  remain  for  several  months.  When  the  substance 
was  finally  removed  for  continuing  the  work,  it  was  found  to  have 
lost  its  optical  properties ;  it  had  become  practically  inactive.  At 
the  same  time  it  had  increased  its  reducing  power.  It  was  rather 
expected  in  the  beginning  that  this  sugar,  notwithstanding  the  fact 
of  its  peculiar  properties,  might  be  a  common  form,  either  dextrose 
or  laevulose.  The  data  obtained,  however,  practically  excluded  such 
a  possibility.  The  fact  that  it  becomes  inactive  on  standing  makes 
the  problem  complex.  In  becoming  inactive,  the  sugar  undoubt- 
edly breaks  down,  resulting  in  either  a  simpler  inactive  sugar, 
together  with  certain  inactive  by-products,  or  in  two  sugars  with 
equal  dextro  and  laevo  properties.  The  latter  is  only  a  bare  possi- 
bility, the  former  is  probable. 
From  recent  stereochemical  developments  of  the  sugar  group  by 
E.  Fischer,  a  great  number  of  isomeric  forms  is  possible.  Many  of 
these  forms  have  already  been  made  synthetically,  while  a  few  have 
been  found  in  nature.  Most  of  those  forms  thus  far  found  in  nature 
belong  to  the  so-called  mono-  and  di-saccharides,  although  it  is  quite 
probable  that  as  our  knowledge  of  the  group  grows,  simpler  forms 
like  erythrose  and  pentose,  together  with  more  complex  forms  like 
heptose,  octose  and  nonose,  will  be  found.  That  many  polymeric 
forms  of  the  monosaccharides  exist  is  evident  from  the  occurrence 
of  raffinose  and  gentianose  and  from  the  peculiar  nature  of  the 
starch  and  cellulose  groups. 
