This  conception  appears  still  more  plainly  in  another  passage,
in  which  he  compares  the  germ-plasm  (the  *  stirp ')  to  a  nation,
and  those  gemmules  ^that  achieve  development,'  —  «>.,  become
transformed  into  the  corresponding  parts  of  the  body  —  *  to
the  foremost  men  of  that  nation,  who  succeed  in  becoming  its
representatives.'

Excellent  as  these  similes  are  in  themselves,  I  cannot  help
thinking  that  they  lead  to  error  if  intended  as  an  explanation
of  ontogeny.  If  we  take  up  the  position  which  Galton  occupies
with  regard  to  the  essential  part  of  the  theory  of  pangenesis,  we
must  suppose  that  a  large  number  of  gemmules  —  many  more
than  are  necessary  for  the  construction  of  the  body  —  are  con-
tained in  the  stirp;  that  is,  in  the  germ-substance  of  the  fer-
tilised egg.  For  only  one  gemmule  is  required  for  each  cell  of
the  body,  but  nevertheless  a  large  number  are  present;  and
these,  so  to  speak,  struggle  for  the  precedence,  the  successful
gemmule  alone  becoming  converted  into  the  cell  which  is  to  be
formed.  In  this  conception  the  fact  is  entirely  overlooked
that  ontogeny  itself  cannot  possibly  depend  on  this  struggle,
but  would  take  place  just  the  same  if  only  one  gemmule  were
present  in  the  *  stirp'  for  each  cell,  and  that  the  cause  for  the
progress  of  development  must  therefore  be  sought  elsewhere
than  in  the  rivalry  between  homologous  gemmules :  it  must  be
due  to  the  right  succession  of  the  gemmules.  Galton  considers
that  the  *  purely  step-by-step-development '  assumed  by  Darwin
in  his  theory  of  pangenesis  is  insufficient,  but  I  think,  neverthe-
less, that  Darwin's  opinion  is  the  more  correct  one.
