488  The  Germination  of  Belladonna  Seed.  {XveZ^r^u"1' 
margin  is  so  small  that 'it  can  hardly  be  taken  to  indicate  that  such  is 
always  the  case.  It  appears,  then,  that  the  small  seeds  are  in  no  wise 
inferior  to  the  larger  ones  in  so  far,  at  least,  as  concerns  the  ger- 
mination. What  the  relative  growth  and  development  of  these  plants 
will  be  is  an  entirely  different  problem.  There  was  little  to  choose, 
between  them  seven  weeks  after  sowing.  However,  any  inferiority 
due  to  seed  would  very  likely  not  become  evident  until  later  in  the 
plant's  development.  A  careful  study  is  being  made  of  this  phase 
of  the  problem  with  special  reference  to  the  relation  of  the  size 
of  the  seed  to  the  development  of  alkaloids  in  the  plants  grown 
therefrom.  It  is  interesting  to  note  that  the  progress  of  the  ger- 
mination is  very  similar  in  the  two  kinds  of  seeds,  as  Figure  2  plainly 
shows. 
Relation  of  Weight  of  Seed  to  Germination. 
While  the  size  of  the  seed  was  found  to  have  nothing  to  do  with 
the  germinating  power,  the  question  of  the  weight  of  the  seed  prom- 
ised to  be  of  greater  importance.  Like  most  other  seeds,  a  consider- 
able percentage  of  belladonna  seed  is  much  lighter  than  the  average. 
It  is  a  question  of  specific  gravity,  there  being  no  relationship  as  to 
size.  In  order  to  determine  the  percentage  of  the  seed,  which  is 
generally  found  to  be  inferior  as  to  weight,  a  method  of  separating 
the  light  from  the  heavy,  based  on  the  specific  gravity  of  the  seed, 
was  used,  which  was  briefly  as  follows:  10  Gms.  of  seeds  previously 
cleaned  from  husks  and  all  inert  matter  are  thrown  into  a  tall,  lipped 
beaker  of  1  litre  capacity  and  half  full  of  water.  After  thorough 
stirring  to  enable  all  the  seeds  to  become  wet,  the  water  is  brought  to 
a  stop  and  the  heavy  seeds  allowed  to  settle  on  the  bottom,  while  the 
light  ones  remain  on  or  near  the  surface.  The  latter  are  then  care- 
fully decanted  into  a  Gooch  crucible  (the  perforations  in  such  a 
crucible  are  just  small  enough  to  prevent  the  seeds  from  going 
.  through)  attached  to  a  vacuum  flask.  With  a  strong  current  of  air 
pulling  through  the  crucible  and  occasional  stirring  the  seeds  are 
soon  dry  and  can  then  be  weighed.  The  heavy  seeds  are  filtered  off 
and  dried  in  a  similar  way.  According  to  this  method,  six  10-gramme 
portions  from  one  general  lot  of  seeds  were  separated  into  the  light 
and  heavy  portions  to  determine  the  accuracy  of  the  method.  The 
volume  of  each  portion  was  determined  by  placing  the  seeds  in  a 
