416  Modification  of  Color  in  Plants.       \  Amj^9p2^rm' 
b.  Glucosides,  which  on  the  action  of  ferments  yield  color 
substances  as  those  forming  the  yellow  pigment,  quer- 
cetin. 
c.  Substances  which  possess  a  basic  radical  or  chromo- 
phore,  and  which  manifest  distinctive  colors  depending 
upon  the  arrangement  .  of  certain  groups  and  side 
chains.  There  is  a  disposition  by  some  authors  to  con- 
sider that  the  shades  of  color  are  due  to  an  enzymic 
action  on  the  chromatin.  It  is  not  easy  to  refute  this 
latter  claim  as  enzymes  are  always  present  in  the  plant 
cell,  and  it  is  not  always  easy  to  dissociate  the  action 
of  the  enzymes  from  that  of  other  substances  which 
are  capable  of  producing  equal  changes  in  the  color 
of  a  pigment.  That  there  are  very  many  substances 
capable  of  producing  color  changes  in  plant  pigments 
is  well  known,  but  unfortunately  these  changes  are  not 
due  in  the  plant  cell  to  the  replacement  of  the  hydrogen 
ion  with  some  basic  radical.  A  microscopical  study  of 
plant  organs  containing  anthocyanin  colors  usually 
show  in  the  different  cells  varying  reactions  which, 
while  they  might  be  ascribed  as  being  due  to  enzymes, 
are  more  likely  to  be  the  result  of  the  interaction  with 
other  substances. 
SOME  EXPERIMENTS  ON  THE  MODIFICATION  OF 
COLOR  IN  PLANTS. 
By  Dr.  Henry  Kraemer,  Mt.  Clemens,  Mich. 
The  study  of  color  in  plants  may  be  pursued  in  several  direc- 
tions: I.  They  may  be  biological  or  functional.  2.  They  may  be 
chemical  or  constitutional.  3.  Or  they  may  be  physiological  or  cellu- 
lar. Studies  involving  any  experiments  with  the  view  of  modifying 
color  in  plants  are  fundamental  studies  connected  with  the  physiology 
of  the  plant  cell. 
Probably  the  most  fundamental  studies  are  those  which  are  of 
a  chemical  nature  in  which  the  constitution  of  color  compounds  is 
