Am.  Jour.  Pharm. 
July,  1909. 
Charles  Darwin. 
35i 
entitled  "  Power  of  Movement  in  Plants,"  where,  with  this  title  as 
a  text,  Darwin  shows  that  apparently  every  growing  part  of  every 
plant  is  continually  circumnutating  though  often  on  a  small  scale, 
and  in  this  universally  present  movement  we  have  the  basis  for  the 
acquirement  of  the  most  diversified  movements.  Thus,  the  great 
sweeps  made  by  the  stems  of  twining  plants  and  by  the  tendrils  of 
other  climbers  result  from  a  mere  increase  in  the  amplitude  of  the 
ordinary  movement  of  circumnutation.  The  leaves  of  various  plants, 
as  the  clover,  sleep  at  night,  in  other  cases  various  organs  show 
movements  to  the  light  or  from  the  light,  as  again  are  equally 
prevalent  movements  of  stems,  etc.,  towards  the  zenith,  and  of  roots 
towards  the  centre  of  the  earth.  Darwin  laid  the  foundation  for  the 
ecologic  study  of  these  various  tropisms  which  the  use  of  modern 
experimental  methods  of  research  have  extended  and  made  more 
exact  by  the  automatic  recording  of  the  movements  by  suitably 
designed  apparatus  connected  with  the  growing  plant. 
Other  botanists  may  have  exceeded  Darwin  in  the  extent  and 
variety  of  their  discoveries,  but  Darwin  represents  an  era  of  philo- 
sophic thought,  and  as  the  centre  of  the  intellectual  maelstrom 
which  his  theories  created,  he  naturally  stands,  as  Saul  did  of  old, 
head  and  shoulders  above  his  scientific  contemporaries.  One  of  the 
greatest  of  these  was  Karl  Naegeli.  He  was  one  of  the  first  among 
German  botanists  to  introduce  a  strict  method  of  thought,  but 
Naegeli's  method  was  applied  to  facts  which  as  facts  were  in- 
accurately observed.  Darwin  collected  data  from  the  literature 
in  support  of  an  idea,  Naegeli  applied  his  logic  to  observations 
which  were  in  part  untrustworthy,  but  this  much  must  be  said  that 
Darwin's  "  Origin  of  Species,"  published  in  the  year  1859,  delivered 
us  from  the  unlucky  dogma  of  constancy.  He  removed  the  medise- 
vally  placed  shackles  from  the  theories  of  the  organic  world  and 
introduced  a  new  philosophy  more  in  harmony  with  the  facts — the 
end  of  which  is  not  yet. 
