It  was  soon,  however,  perceived  by  those  who  studied  the  Vegetable
Kingdom  profoundly,  that  no  improvement  could  be  made  in  the  knowledge
of  its  true  nature,  of  the  best  manner  of  arranging  it,  or  even  of  the  pur-
poses to  which  it  might  be  applied,  unless  the  philosophy  of  the  subject  was
investigated  ;  and  this  became  daily  more  apparent  as  the  materials  col-
lected by  botanical  travellers  accumulated.  It  was  found  that  the  few
thousand  ill-examined  plants  which  inhabit  Europe  gave  a  most  imperfect
idea  of  the  vegetation  of  the  globe  ;  that  methods  of  classification  which
were  tolerable  so  long  as  species  were  few,  became  useless,  or  an  incum-
brance as  the  number  increased,  and  that  no  real  progress  in  Botany,  as  a
branch  of  science,  could  be  hoped  for  so  long  as  a  few  arbitrary  signs  were
taken  as  the  basis  of  all  arrangement.  The  older  Botanists  knew  little  of
vegetable  physiology ;  and  of  the  laws  of  vegetable  structure  they  had  at  the
most  but  a  glimmering  perception.  Yet  those  subjects  are  the  founda-
tion of  all  sound  principles  of  classification.  The  recognition  of  that  fact
immediately  led  to  the  investigation  of  new  branches  of  knowledge,  in
which  discoveries  were  daily  made,  and  it  has  terminated  in  a  universal
adoption  of  the  principles  of  Ray,  improved  and  extended  by  the  admirable
views  of  Jussieu,  as  developed  in  his  Genera  Plantarum  secundum  Ordines

h2


XXIV  INTRODUCTION.
Naturales  disposita, — a  book  of  wonderful  sagacity  and  most  profound
research.
