X22*KT}     Next  Steps  in  Botanical  Science.  69 
is  easy  to  interest  a  boy  in  the  thing  that  responds,  whether  it  be 
a  kicking  frog  stimulated  by  an  electrical  discharge,  or  a  green 
plant  whose  stimulation  is  a  properly  directed  beam  of  sunlight. 
And  yet  it  is  well  for  us  to  remember  that  the  plant  is  first  of  all 
a  structure,  whose  complexity  may  well  challenge  the  most  acute 
minds.  We  find  it  far  easier  to  record  the  responses  of  plants  to 
our  planned  stimuli  than  to  unravel  a  structural  complex,  and  so 
no  doubt  we  shall  continue  to  entertain  ourselves  and  our  students 
with  what  are  too  often  futile  experiments. 
In  this  part  of  the  botanical  field  are  pathology,  which  grew 
up  from  our  observation  that  organs  may  not  respond  normally ; 
ecology,  which  developed  from  the  observation  that  plants  tend  to 
live  in  communities  ;  and  phytogeography,  having  to  do  with  the 
means  for  and  the  results  of  distribution.  There  are  signs  that 
for  economic  reasons  pathology  may  become  rather  sharply  set 
off  from  physiology,  of  which  it  is  properly  a  part,  much  as  through 
the  zeal  and  enthusiasm  of  the  ecologists  there  was  once  the  sug- 
gestion of  a  physiological  schism.  The  latter  is  happily  no  longer 
imminent,  and  it  may  be  hoped  that  it  will  not  again  threaten  the 
unity  of  plant  physiology.  And  so  it  may  be  hoped  that  the 
pathologists  will  not  wholly  secede  from  association  with  the 
physiologists. 
Taxonomy,  or  as  we  used  to  call  it,  classification,  occupying  the 
third  division  of  the  field  of  botany,  long  received  the  almost 
exclusive  attention  of  botanists.  And  even  to-day  it  is  the  pretty 
general  opinion  of  our  non-botanical  friends  that  we  are  constantly 
employed  in  collecting  specimens,  and  in  seme  intricate  and  mys- 
terious way  determining  their  classification  and  affixing  to  them 
their  proper  Latin  names.  And  it  must  be  admitted  that  every 
botanist  does  a  good  deal  of  just  such  work,  quite  as  every  chemist 
makes  many  analyses,  and  tries  to  arrange  in  orderly  sequence  the 
chemical  substances  which  he  has  in  his  cabinet,  and  the  astronomer 
classifies  and  names  the  heavenly  bodies  with  which  his  science 
deals.  At  first  even  the  botanists  knew  but  few  plants,  just  as 
now  most  men  know  scarcely  more  than  a  score.  But  as  the 
botanists  came  to  know  a  larger  number  of  plants,  it  was  impera- 
tive that  they  should  be  named,  and  then  grouped  conveniently  for 
easier  reference.  Thus  arose  such  crude,  primitive  classes  as  herbs, 
shrubs  and  trees,  which  served  their  purpose  until  the  numbers 
became  too  great  a^ain,  when  additional  structural  differences  were 
