NEW  RESEARCP1ES  ON  STARCH. 
139 
it  began  to  assume  a  brown  color,  on  examining  the  granules  with  the  mi- 
croscope the  nuclei  were  observed  to  be  enlarged  and  the  striae  rendered 
more  distinct,  results  which  were  ascribed  to  the  action  of  vapor  produced 
by  the  heat,  within  the  cavities.  Another  experiment  which  had  been  tried 
consisted  in  mixing  starch  with  gum-water,  and  after  allowing  the  mass  to 
dry,  cutting  it  into  very  thin  slices,  when  many  of  the  granules  were  found 
to  have  been  cut  through,  and  on  examining  these  sections  with  the  micro- 
scope, especially  after  treating  them  with  solution  of  iodine  and  dilute  sul- 
phuric acid,  strong  evidence  of  the  existence  of  separate  layers  was  ob- 
tained. By  these  and  other  experiments  he  thought  it  had  been  pretty 
clearly  shown  that  the  starch  granule  was  composed  of  a  series  of  hollow 
scales,  and  he  believed  with  Schleiden  and  others,  that  these  were  deposited 
from  within  outwards.  Another  question,  however,  presented  itself, 
namely,  are  the  different  layers  in  the  granule  of  the  same  chemical  com- 
position, or  of  the  same  relative  density  ?  He  considered  that  the  layers 
varied  in  density,  the  inner  layers  being  more  aqueous  and  gelatinous  than 
the  outer,  which  appeared  generally  to  be  altogether  of  a  tougher  consist- 
ence. He  thought  the  layers  had  all  the  same  chemical  composition  in  the 
larger  and  perfectly  formed  granules,  but  it  might  be  doubted  whether  the 
small  rudimentary  granules  did  not  consist  of  a  transitional  substance  not 
identical  with  starch,  but  which  would  become  starch. —  Transactions  Pharm. 
Society,  in  Pharm  Jour.  Dec.  1854. 
NEW  RESEARCHES  ON  STARCH. 
By  M.  A.  Bechamp. 
During  some  researches  on  xyloidine,  the  author  has  studied 
the  action  of  nitric  acid,  sulphuric  acid,  crystallizable  acetic  acid, 
chloride  of  zinc,  and  caustic  alkalies  upon  starch.  He  considers 
that  the  insolubility  of  starch  is  not  dependent  upon  its  organi- 
zation, and  that  the  substance  soluble  in  cold  water,  known  to 
chemists  as  dextrine  colorable  hy  iodine,  is  a  modification  of  starch 
intermediate  between  it  and  pure  dextrine. 
If  starch  be  treated  with  very  concentrated  nitric  acid  (a  mix- 
ture of  equal  parts  of  NO5  4HO  and  NO5  HO,)  it  is  first  of  all 
converted  into  a  thick  paste,  which  at  last  dissolves  in  an  excess 
of  acid.*  The  addition  of  a  sufficient  quantity  of  concentrated 
alcohol  separates  the  whole  of  the  starch  in  the  form  of  a  sticky 
mass,  which,  when  washed  with  alcohol,  is  reduced  to  a  white 
powder,  perfectly  neutral  to  litmus  paper.    This  subst'ance  is 
*  The  liquid  obtained  is  entirely  soluble  in  cold  water,  &o  that  no  xyloidine 
can  have  been  formed. 
