AsTptJemberhia9o^"}        Plant  Morphology  and  Taxonomy.  407 
In  considering  the  history  of  the  morphological  study  of  plants, 
mention  should  be  made  of  the  important  work  which  was  carried 
on  by  Sachs  (1 858-1875).  By  the  introduction  of  his  method  of 
plant  cultures  and  apparatus  for  controlling  the  conditions  under 
which  plants  grow  he  not  only  contributed  to  our  knowledge  of 
plant  physiology,  but  also  made  many  observations  having  a  bearing 
on  experimental  morphology.  The  methods  used  by  Sachs  have 
been  extended  and  perfected  in  recent  years,  and  in  the  hands  of 
Goebel  and  other  investigators  have  yielded  results  which  have 
materially  assisted  in  raising  plant  physiology  and  plant  mor- 
phology to  the  high  plane  which  they  now  occupy,  and  which 
furthermore  show  the  interdependence  of  these  two  divisions  of 
botanical  science.  In  the  same  manner  have  the  methods  of 
research  instituted  by  De  Bary  yielded  such  fruitful  results  in  the 
hands  of  Klebs  and  others  in  their  studies  on  the  lower  orders  of 
plants. 
Following  Hofmeister,  who  may  be  regarded  as  the  founder  of 
experimental  morphology,  Sachs  did  very  much  to  give  direction 
to  the  newer  morphology  which  has  been  developed,  particularly 
in  the  past  fifteen  or  twenty  years. 
Sachs  was,  however,  a  representative  of  what  may  be  considered  a 
transition  period  between  the  older  formal  morphology  which  con- 
sidered the  external  configuration  of  plants  independent  of  their 
function  and  physiological  activities,  and  the  newer  morphology 
which  considers  that  the  form  and  function  of  an  organ  stand  in  the 
most  intimate  relation  to  each  other.  In  the  chapter  on  "  Mor- 
phology of  the  External  Conformation  of  Plants,"  as  given  in  his 
text-book  of  botany,  Sachs  says 
The  parts  of  plants  which  are  ordinarily  termed  their  organs,  very  vari- 
ous in  their  form  and  serving  different  physiological  purposes,  may  be  con- 
sidered scientifically  from  two  different  points  of  view.  The  question  may  be 
asked  at  the  outset  :  How  far  are  these  parts  adapted,  by  their  form  and 
structure,  to  perform  their  physiological  work  ?  In  this  case  they  are  regarded 
from  one  side  only  as  instruments  or  organs,  and  this  mode  of  regarding  them  is 
itself  a  part  of  physiology.  Or  else  these  relationships  may,  for  the  time, 
be  completely  put  aside,  and  the  question  may  be  kept  out  of  consideration 
what  functions  the  parts  of  the  plant  have  to  fulfil,  and  the  only  point  kept  in 
view  may  be  where  and  how  they  arise,  in  what  manner  the  origin  and  growth 
of  one  member  are  related  in  space  and  time  to  those  of  another.  This  mode 
of  regarding  them  is  the  morphological  one.  It  is  obvious  that  this  mode 
is  as  one-sided  as  the  physiological ;  but  investigation  and  description  require, 
