"Care  must  be  taken,  however,  that  no  new  material  is
introduced  under  this  head.  The  object  is  still  to  prepare  the
mind  for  new  material  that  is  to  follow.  As  has  often  been  said,
the  mind  is  not  a  vessel  into  which  we  can  at  will  put  what  we
wish.  Only  in  proportion  as  the  new  comes  into  relationship
with  what  is  already  in  the  mind  will  the  mind  retain  it.  Only
in  proportion  as  the  new  is  assimilated  with  the  old  in  the  mind
can  the  mind  use  it.
