Am.  Jour.  Pharm. 
May,  1907. 
The  Structure  of  the  Starch  Grain. 
219 
when  Arthur  Meyer  (ig)  demonstrated  that  the  substance  termed 
cellulose  by  Nageli,  and  which  was  termed  i(  farinose  "  by  Von  Mohl 
(2)  /3-amylose,  and  (3)  amylodextrin,  a  decomposition  product  of 
amylose.  He  also  expressed  the  opinion  that  inasmuch  as  there  is 
an  anhydride  of  dextrose  which  does  not  readily  take  up  water, 
there  is  probably  also  an  anhydride  of  amylose  which  even  on  boiling 
with  water  is  hydrated  with  difficulty,  and  that  this  is  the  substance 
that  has  given  rise  to  the  belief  that  there  is  present  a  starch  cellu- 
lose. This  latter  term,  according  to  Meyer,  has  been  used  for  a 
number  of  different  substances:  (i)  mixtures  of  amylodextrin  and 
a-amylose  ;  (2)  solutions  of  a -amylose  and  /3-amylose  ;  (3)  solutions 
of  /3-amylose  with  various  other  substances,  as  nitrogen-holding 
substances,  impure  fatty  products,  pure  amylodextrin,  and  the  walls 
of  plant  cells  which  are  contained  in  commercial  starches  unless 
carefully  purified.  He  obtained  the  a-amylose  upon  treating  starch 
paste  (Starkekleister)  with  malt  solutions  (Malzauszug)  and  by  the 
action  of  hot  dilute  solutions  of  hydrochloric  acid  upon  the  whole 
starch  grain.  The  portion  remaining  (/3-amylose)  is  distinguished 
from  the  portion  dissolved  in  that  it  is  not  soluble  in  water  and 
becomes  slightly  reddish,  and  not  blue  with  iodine. 
One  of  the  earliest  views  in  regard  to  the  development  of  the 
starch  grain  was  that  new  layers  were  added  to  those  previously 
formed,  these  being  separated  from  each  other  by  layers  of  air  which 
were  later  called  (i  Adhasionsflachen,"  "  Contactflachen,"  and 
"  Grenzflachen  "  by  Dippel  (22),  Strasburger  (23),  and  Krabbe  (24), 
respectively.  These  terms,  however,  have  been  mostly  used  by 
these  authors  in  describing  the  structure  of  cell  walls.  In  1858 
Nageli  (16)  advanced  the  theory  that  the  starch  grain  consists  of 
elementary  particles,  later  termed  by  him  "  micellae,"  which  he  sup- 
posed to  have  the  form  of  parallelopipedal  prisms  with  rectangular 
or  rhomboid  bases.  Furthermore,  according  to  Nageli,  these 
micellae  possess  a  watery  him,  are  embedded  in  a  mother  liquor 
which  differs  from  them  in  composition,  and  are  held  together  by 
certain  forces.  The  growth  of  the  starch  grain  is  effected  by  the 
interpolation  of  new  material  among  the  particles  already  formed, 
this  new  substance  being  utilized  in  part  in  increasing  the  size  of 
