﻿184 
  Retrograde 
  Varieties 
  

  

  be 
  answered 
  by 
  long 
  and 
  arduous 
  work 
  in 
  well- 
  

   equipped 
  laboratories; 
  they 
  are 
  not 
  to 
  be 
  at- 
  

   tempted 
  by 
  every 
  one. 
  But 
  there 
  are 
  other 
  

   problems 
  which 
  the 
  most 
  complete 
  of 
  institu- 
  

   tions 
  are 
  not 
  able 
  to 
  study 
  if 
  opportunity 
  is 
  not 
  

   offered 
  them, 
  and 
  such 
  opportunities 
  are 
  apt 
  to 
  

   occur 
  more 
  often 
  in 
  fields, 
  gardens, 
  parks, 
  

   woods 
  and 
  plains, 
  than 
  in 
  the 
  relatively 
  small 
  

   experimental 
  gardens 
  of 
  even 
  the 
  largest 
  in- 
  

   stitution. 
  Therefore, 
  whosoever 
  has 
  the 
  good 
  

   fortune 
  to 
  find 
  such 
  sports, 
  should 
  never 
  allow 
  

   the 
  occasion 
  to 
  pass 
  without 
  making 
  an 
  investi- 
  

   gation 
  that 
  may 
  bring 
  results 
  of 
  very 
  great 
  im- 
  

   portance 
  to 
  science. 
  

  

  