^epimbw^ifloS'*}        Plant  Morphology  and  Taxonomy.  409 
propositions  respecting  the  arrangement  of  their  organs,  considered  as  so  many 
inert  parts  ;  and  though  we  may  establish  several  wide  conclusions  respecting 
the  separate  and  combined  actions  of  their  organs;  without  knowing  anything 
definite  respecting  the  forms  and  positions  of  their  present  organs  ;  yet  we  can 
not  reach  such  a  rationale  of  the  facts  as  the  hypothesis  of  evolution  aims  at, 
without  contemplating  structures  and  functions  in  their  mutual  relations, 
Everywhere  structures  in  great  measure  determine  functions  ;  and  everywhere 
functions  are  incessantly  modifying  structures.  In  nature  the  two  are  insepara- 
ble co-operators  ;  and  science  can  give  no  true  interpretations  of  nature  without 
keeping  their  co-operation  constantly  in  view.  An  account  of  organic  evolu- 
tion in  its  more  special  aspect,  must  be  essentially  an  account  of  the  inter- 
actions of  structures  and  functions,  as  perpetually  altered  by  changes  of  con- 
ditions. 
At  the  present  time  Goebel  probably  stands  as  the  chief  exponent 
of  the  newer  morphology,  In  his  book  on  the  organography  of 
plants  he  has  presented  some  of  the  arguments  in  favor  of  this 
newer  conception  in  regard  to  plant  structures,  and  in  a  most  charac- 
teristic and  clever  manner  has  substituted  the  word  *'  organography  " 
for  that  of  "  morphology,"  and  thus  frees  himself  of  the  older  con- 
ceptions in  regard  to  the  subject,  and  at  the  same  time  adopts  a 
more  expressive  term.  According  to  Goebel  the  morphologist 
should  look  upon  the  form  of  plants  as  an  expression  of  living  pro- 
cesses. He  should  endeavor  to  determine  in  what  degree  the  form 
of  an  organ  shows  an  adaptation  to  external  conditions  and  to  what 
extent  it  is  dependent  upon  these  and  internal  conditions.  To  make 
a  practical  application  of  his  meaning,  Goebel  says  that  he  considers 
it  infinitely  more  important  to  determine  the  factors  which  cause  the 
inequilateral  development  of  a  leaf,  as  of  begonia,  than  to  construct 
a  phylogenetic  hypothesis  unsupported  by  facts,  and  in  summing  up 
his  arguments  on  the  subject  of  morphology,  or  organography,  he 
says : — 
The  idea  that  morphology  has  nothing  to  do  with  the  function  of  organs 
has  been  acquired  entirely  because  the  fact  has  been  overlooked  that  the  trans- 
formations seen  in  organs  are  conditioned  by  a  change  of  function.  Their 
functions  therefore  have  been  treated  as  subordinate  in  determining  the  charac- 
ters of  organs,  and  the  external  relations  alone  have  been  taken  as  the  chief 
points  for  consideration.  But  the  relationships  of  mere  form  are  by  no  means 
the  permanent  ones  'in  the  tide  of  phenomena.'  They  also  change,  The 
determination  of  this  change,  that  is  to  say,  of  the  alterations  which  have  taken 
place,  and  are  believed  to  take  place,  in  the  formation  of  organs  of  a  natural 
group,  is  one  of  the  weightiest  tasks  of  organography.  If  we  separate  function 
from  form  we  are  at  once  led  into  altogether  unfruitful  speculations. 
